¿Estamos ganando terreno sobre la infección ocular?

<div dir="ltr" style="text-align: left;" trbidi="on"> Visualización optima 1600x900 pixel Comenta.esta.publicación<br /> Para Publicaciones en otros idiomas te invitamos a utilizar el traductor incorporado en infolentes<br /> <br /> <br /> <h5 style="background-color: #fefefd; font-family: Tahoma, Arial, Helvetica; font-size: 13px; margin: 0px 0px 10px; padding: 0px;"> <span style="font-family: Tahoma, Arial, Helvetica, sans-serif;"><span class="">Las fluoroquinolonas tópicas de nueva generación son algunos de los antibióticos más eficaces que he visto nunca. </span>Pero, aumento de la resistencia bactericida sigue siendo una preocupación.</span></h5> <span style="background-color: #fefefd; color: #333333; font-family: Tahoma, Arial, Helvetica, sans-serif; font-size: 12px;">Por Elizabeth D. Muckley, OD 12/17/2012</span><br /> <span style="background-color: #fefefd; color: #333333; font-family: Tahoma, Arial, Helvetica, sans-serif; font-size: 12px;"><br /></span> <div style="text-align: justify;"> </div> <div class="MsoNormal"> <span style="background: #FEFEFD; color: #333333; font-family: "Tahoma","sans-serif";">Sin embargo, todas las fluoroquinolonas de nueva generación se utilizan fuera de las indicaciones para numerosas condiciones de queratitis ulcerativa en la prevención de infecciones en la atención pre-y post-quirúrgicos.<span class="apple-converted-space"> </span>Mirando hacia atrás en los últimos 20 años, debemos preguntarnos si estos medicamentos están cumpliendo con su promesa y lo que será el futuro de la gestión de la infección ocular y la prevención como aspecto?<span class="apple-converted-space"> </span>En cualquier caso, nuestra mayor preocupación en el futuro es el desarrollo de nuevos patrones de resistencia a las fluoroquinolonas tópicas.<span class="apple-converted-space"> <o:p></o:p></span></span></div> <div class="MsoNormal"> <span style="background: #FEFEFD; color: #333333; font-family: "Tahoma","sans-serif";"><span class="apple-converted-space"><br /></span></span></div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKgXrk1he8uc_HPWIfpt_Dd-oLpW8JdYerN1oXPQt2U4mI5_p6G_94TgisApCPZzrguOCRT0gMYF6QCvY-UaazcE0XvKVsTcXGgj12pPNMTqLJodPdoJorciLk7mMqe30tMCaFftFV-ro/s1600/038_ro1212_f2-1.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKgXrk1he8uc_HPWIfpt_Dd-oLpW8JdYerN1oXPQt2U4mI5_p6G_94TgisApCPZzrguOCRT0gMYF6QCvY-UaazcE0XvKVsTcXGgj12pPNMTqLJodPdoJorciLk7mMqe30tMCaFftFV-ro/s400/038_ro1212_f2-1.gif" width="400" /></a></div> <div class="separator" style="clear: both; text-align: center;"> <br /></div> <div class="separator" style="clear: both; text-align: center;"> <strong style="background-color: #fefefd; color: #333333; font-family: Tahoma, Arial, Helvetica, sans-serif; text-align: start;">Este paciente se presentó con un pronunciado <em>Pseudomonas</em> úlcera. ¿Cuál es la estrategia de tratamiento más eficaz?</strong></div> <div class="separator" style="clear: both; text-align: center;"> <strong style="background-color: #fefefd; color: #333333; font-family: Tahoma, Arial, Helvetica, sans-serif; text-align: start;"><br /></strong></div> <div class="separator" style="clear: both; text-align: center;"> </div> <div class="MsoNormal" style="text-align: justify;"> <span style="background: #FEFEFD; color: #333333; font-family: "Tahoma","sans-serif";">Sin embargo, todas las fluoroquinolonas de nueva generación se utilizan fuera de las indicaciones para numerosas condiciones de queratitis ulcerativa en la prevención de infecciones en la atención pre-y post-quirúrgicos.<span class="apple-converted-space"> </span>Mirando hacia atrás en los últimos 20 años, debemos preguntarnos si estos medicamentos están cumpliendo con su promesa y lo que será el futuro de la gestión de la infección ocular y la prevención como aspecto?<span class="apple-converted-space"> </span>En cualquier caso, nuestra mayor preocupación en el futuro es el desarrollo de nuevos patrones de resistencia a las fluoroquinolonas tópicas.<span class="apple-converted-space"> </span></span></div> <div class="MsoNormal" style="text-align: justify;"> <span style="background: #FEFEFD; color: #333333; font-family: "Tahoma","sans-serif";"><span class="apple-converted-space"><br /></span></span></div> <div class="MsoNormal" style="text-align: justify;"> <span style="background: #FEFEFD; color: #333333; font-family: "Tahoma","sans-serif";"><span class="apple-converted-space"></span></span></div> <div style="font-family: Tahoma, Arial, Helvetica, sans-serif; margin-bottom: 12px; text-align: -webkit-left;"> <span style="font-family: Arial;"><strong style="font-family: Tahoma, Arial, Helvetica, sans-serif;"><span style="color: brown;">Mechanism of Action</span></strong> <br style="font-family: Tahoma, Arial, Helvetica, sans-serif;" />Topical fluoroquinolones are antibiotic agents that block bacterial DNA synthesis by inhibiting the topoisomerase enzymes. Older-generation topical fluoroquinolones (ciprofloxacin, ofloxacin and levofloxacin) specifically target the DNA enzyme topoisomerase IV, which is more susceptible in gram-negative bacteria.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">1,2</sup> However, the fourth-generation fluoroquinolones (moxifloxacin, gatifloxacin) contain a substitution of a methoxy group at position eight of the quinolone ring, which additionally facilitates topoisomerase II (DNA gyrase) inhibition in gram-positive organisms. </span></div> <div style="font-family: Tahoma, Arial, Helvetica, sans-serif; margin-bottom: 12px; text-align: -webkit-left;"> <span style="font-family: Arial;">This dual mechanism of action promotes increased bactericidal activity against gram-positive organisms without sacrificing the gram-negative coverage provided by older-generation fluoroquinolones.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">3</sup> Most importantly, targeting both topoisomerase II and IV likely reduces resistance because concomitant mutations in both genes are much less likely to occur than a single mutation in one gene.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">4,5</sup> </span></div> <div style="font-family: Tahoma, Arial, Helvetica, sans-serif; margin-bottom: 12px; text-align: -webkit-left;"> <span style="font-family: Arial;"><strong style="font-family: Tahoma, Arial, Helvetica, sans-serif;"><span style="color: brown;">Drug Penetration and Tissue Concentration</span></strong> <br style="font-family: Tahoma, Arial, Helvetica, sans-serif;" />For topical fluoroquinolones to be effective in the treatment of ocular infections, they must exhibit satisfactory minimum inhibitory concentration (MIC) scores, high penetration rates into ocular tissues/aqueous and broad susceptibility profiles, as well as posess the ability to thwart resistance. </span></div> <div style="font-family: Tahoma, Arial, Helvetica, sans-serif; margin-bottom: 12px; text-align: -webkit-left;"> <span style="font-family: Arial;">The MIC is defined as the lowest possible concentration of an antibiotic that is able to prevent overnight micro-organism growth in a tissue culture. Typically, MIC90 (the MIC score required to inhibit bacterial growth in at least 90% of targeted strains) is the standard measure of bactericidal efficacy for topical anti-infective agents. Note that the lower the MIC90 value, the more potent the agent is against a given isolate.</span></div> <div style="font-family: Tahoma, Arial, Helvetica, sans-serif; margin-bottom: 12px; text-align: -webkit-left;"> <span style="font-family: Arial;">The ocular surface poses a challenge to drug administration and pharmacokinetics. Tears act as a drug-delivery barrier, effectively diluting the agent and facilitating drainage via the nasolacrimal system upon rapid blinking following instillation.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">6</sup> Therefore, MIC scores derived from in vitro laboratory testing may not accurately reflect on-eye MIC values. Delivering the drug to the target tissue, as well as remaining there long enough to be effective in vivo, is of equal importance. Compared to their systemic counterparts, topical antibiotics often must be dosed at higher concentrations to increase drug penetration and sustain effective therapeutic levels. </span></div> <div style="font-family: Tahoma, Arial, Helvetica, sans-serif; margin-bottom: 12px; text-align: -webkit-left;"> <span style="font-family: Arial;">The fourth-generation fluoroquinolones offer the best penetration profile; in particular, moxifloxacin and 1.5% levofloxacin fared well in corneal penetration studies.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">7-9, 15-18</sup></span></div> <div style="font-family: Tahoma, Arial, Helvetica, sans-serif; margin-bottom: 12px; text-align: -webkit-left;"> <span style="font-family: Arial;"><sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;"><br /></sup></span></div> <div style="font-family: Tahoma, Arial, Helvetica, sans-serif; margin-bottom: 12px; text-align: -webkit-left;"> <table bgcolor="#F0C2CC" bordercolor="" cellpadding="" cellspacing="" style="border-collapse: collapse; border: 0px; color: #333333; font-size: 12px; height: 444px; margin: 10px; text-align: center; width: 494px;"><tbody> <tr><td colspan="5" style="padding: 3px; text-align: center;" valign="top"><span style="font-size: small;"><strong>Commonly Prescribed Topical Fluoroquinolones</strong></span> </td></tr> <tr><td style="padding: 3px; text-align: center;"><em><span style="font-family: Arial; font-size: x-small;">Generic Name</span></em></td><td style="padding: 3px; text-align: center;"><em><span style="font-family: Arial; font-size: x-small;">Brand Name and Approval Date</span></em></td><td style="padding: 3px; text-align: center;"><em><span style="font-family: Arial; font-size: x-small;">Manufacturer</span></em></td><td style="padding: 3px; text-align: center;"><em><span style="font-family: Arial; font-size: x-small;">Classification</span></em></td><td style="padding: 3px; text-align: center;" valign="middle"><em><span style="font-family: Arial; font-size: x-small;">Indication</span></em></td></tr> <tr><td style="padding: 3px; text-align: center;"><span style="font-family: Arial; font-size: x-small;">0.3% Ciprofloxacin</span></td><td style="padding: 3px;"><div style="text-align: center;"> <span style="background-color: transparent; font-family: Arial; font-size: x-small;">Ciloxan, </span></div> <span style="font-family: Arial; font-size: x-small;"><div style="text-align: center;"> <span style="background-color: transparent;">December 1990</span></div> </span></td><td style="padding: 3px; text-align: center;"><span style="font-family: Arial; font-size: x-small;">Alcon, generic </span></td><td style="padding: 3px; text-align: center;"><span style="font-family: Arial; font-size: x-small;">2nd Generation</span></td><td style="padding: 3px; text-align: center;" valign="top"><span style="font-family: Arial; font-size: x-small;">Bacterial Conjunctivitis</span></td></tr> <tr><td style="padding: 3px; text-align: center;"><span style="font-family: Arial; font-size: x-small;">0.3% Ofloxacin </span></td><td style="padding: 3px;"><div style="text-align: center;"> <span style="background-color: transparent; font-family: Arial; font-size: x-small;">Ocuflox, </span></div> <span style="font-family: Arial; font-size: x-small;"><div style="text-align: center;"> <span style="background-color: transparent;">July 1993  </span></div> </span></td><td style="padding: 3px; text-align: center;"><span style="font-family: Arial; font-size: x-small;">Allergan, generic </span></td><td style="padding: 3px; text-align: center;"><span style="font-family: Arial; font-size: x-small;">2nd Generation</span></td><td style="padding: 3px; text-align: center;" valign="top"><span style="font-family: Arial; font-size: x-small;">Bacterial Conjunctivitis</span></td></tr> <tr><td style="padding: 3px; text-align: center;"><span style="font-family: Arial; font-size: x-small;">0.5% Levofloxacin </span></td><td style="padding: 3px;"><div style="text-align: center;"> <span style="background-color: transparent; font-family: Arial; font-size: x-small;">Quixin, </span></div> <span style="font-family: Arial; font-size: x-small;"><div style="text-align: center;"> <span style="background-color: transparent;">August 2000</span></div> </span></td><td style="padding: 3px; text-align: center;"><span style="font-family: Arial; font-size: x-small;">Vistakon</span></td><td style="padding: 3px; text-align: center;"><span style="font-family: Arial; font-size: x-small;">3rd Generation</span></td><td style="padding: 3px; text-align: center;" valign="top"><span style="font-family: Arial; font-size: x-small;">Bacterial Conjunctivitis</span></td></tr> <tr><td style="padding: 3px; text-align: center;"><span style="font-family: Arial; font-size: x-small;">0.3% Gatifloxacin</span></td><td style="padding: 3px;"><div style="text-align: center;"> <span style="background-color: transparent; font-family: Arial; font-size: x-small;">Zymar, </span></div> <span style="font-family: Arial; font-size: x-small;"><div style="text-align: center;"> <span style="background-color: transparent;">March 2003  </span></div> </span></td><td style="padding: 3px; text-align: center;"><span style="font-family: Arial; font-size: x-small;">Allergan </span></td><td style="padding: 3px; text-align: center;"><span style="font-family: Arial; font-size: x-small;">4th Generation</span></td><td style="padding: 3px; text-align: center;" valign="top"><span style="font-family: Arial; font-size: x-small;">Bacterial Conjunctivitis</span></td></tr> <tr><td style="padding: 3px; text-align: center;"><span style="font-family: Arial; font-size: x-small;">0.5% Moxifloxacin</span></td><td style="padding: 3px;"><div style="text-align: center;"> <span style="background-color: transparent; font-family: Arial; font-size: x-small;">Vigamox, </span></div> <span style="font-family: Arial; font-size: x-small;"><div style="text-align: center;"> <span style="background-color: transparent;">April 2003  </span></div> </span></td><td style="padding: 3px; text-align: center;"><span style="font-family: Arial; font-size: x-small;">Alcon</span></td><td style="padding: 3px; text-align: center;"><span style="font-family: Arial; font-size: x-small;">4th Generation</span></td><td style="padding: 3px; text-align: center;" valign="top"><span style="font-family: Arial; font-size: x-small;">Bacterial Conjunctivitis</span></td></tr> <tr><td style="padding: 3px; text-align: center;" valign="top"><span style="font-family: Arial; font-size: x-small;">1.5% Levofloxacin </span></td><td style="padding: 3px;" valign="top"><div style="text-align: center;"> <span style="background-color: transparent; font-family: Arial; font-size: x-small;">Iquix,</span><span style="background-color: transparent; font-size: x-small;"> </span></div> <span style="font-family: Arial; font-size: x-small;"><div style="text-align: center;"> <span style="background-color: transparent;">March 2004</span></div> </span></td><td style="padding: 3px; text-align: center;" valign="top"><span style="font-family: Arial; font-size: x-small;">Vistakon</span></td><td style="padding: 3px; text-align: center;" valign="top"><span style="font-family: Arial; font-size: x-small;">3rd Generation</span></td><td style="padding: 3px; text-align: center;" valign="top"><span style="font-family: Arial; font-size: x-small;">Bacterial Corneal Ulcers</span></td></tr> <tr><td style="padding: 3px; text-align: center;" valign="top"><span style="font-family: Arial; font-size: x-small;">0.6% Besifloxacin</span></td><td style="padding: 3px;" valign="top"><div style="text-align: center;"> <span style="background-color: transparent; font-family: Arial; font-size: x-small;">Besivance,</span><span style="background-color: transparent; font-size: x-small;"> </span></div> <span style="font-family: Arial; font-size: x-small;"><div style="text-align: center;"> <span style="background-color: transparent;">May 2009 </span></div> </span></td><td style="padding: 3px; text-align: center;" valign="top"><span style="font-family: Arial; font-size: x-small;">Bausch + Lomb</span></td><td style="padding: 3px; text-align: center;" valign="top"><span style="font-family: Arial; font-size: x-small;">Novel (no systemic equivalent)</span></td><td style="padding: 3px; text-align: center;" valign="top"><span style="font-family: Arial; font-size: x-small;">Bacterial Conjunctivitis</span></td></tr> <tr><td style="padding: 3px; text-align: center;" valign="top"><span style="font-family: Arial; font-size: x-small;">0.5% Gatifloxacin</span></td><td style="padding: 3px;" valign="top"><div style="text-align: center;"> <span style="background-color: transparent; font-family: Arial; font-size: x-small;">Zymaxid,</span><span style="background-color: transparent; font-size: x-small;"> </span></div> <span style="font-family: Arial; font-size: x-small;"><div style="text-align: center;"> <span style="background-color: transparent;">May 2010</span></div> </span></td><td style="padding: 3px; text-align: center;" valign="top"><span style="font-family: Arial; font-size: x-small;">Allergan</span></td><td style="padding: 3px; text-align: center;" valign="top"><span style="font-family: Arial; font-size: x-small;">4th Generation</span></td><td style="padding: 3px; text-align: center;" valign="top"><span style="font-family: Arial; font-size: x-small;">Bacterial Conjunctivitis</span></td></tr> <tr><td style="padding: 3px; text-align: center;" valign="top"><span style="font-family: Arial; font-size: x-small;">0.5% Moxifloxacin</span></td><td style="padding: 3px; text-align: center;" valign="top"><span style="font-family: Arial; font-size: x-small;">Moxeza,<span style="font-family: Tahoma, Arial, Helvetica, sans-serif; font-size: x-small;"> </span>November 2010 </span></td><td style="padding: 3px; text-align: center;" valign="top"><span style="font-family: Arial; font-size: x-small;">Alcon</span></td><td style="padding: 3px; text-align: center;" valign="top"><span style="font-family: Arial; font-size: x-small;">4th Generation</span></td><td style="padding: 3px; text-align: center;" valign="top"><span style="font-family: Arial; font-size: x-small;">Bacterial Conjunctivitis</span></td></tr> </tbody></table> </div> <div style="font-family: Tahoma, Arial, Helvetica, sans-serif; margin-bottom: 12px; text-align: justify;"> <strong style="background-color: #fefefd; color: #333333;"><span style="color: brown; font-size: small;">Drug Enhancements</span></strong></div> <div style="font-family: Tahoma, Arial, Helvetica, sans-serif; margin-bottom: 12px; text-align: -webkit-left;"> </div> <div style="text-align: justify;"> <span style="background-color: #fefefd; color: #333333; font-family: Arial;">In an effort to amplify antibiotic concentration on the ocular surface and improve penetration, many ocular pharmaceutical companies developed enhanced or reformulated versions of existing fluoroquinolones during the last eight years. For example, Vistakon released Iquix in 2004, which contained more than double the concentration of levofloxacin in Quixin.</span><sup style="color: #333333;">10</sup><span style="background-color: #fefefd; color: #333333; font-family: Arial;">Also, in May 2010, Allergan brought Zymaxid to the market, which contained 0.2% more gatifloxacin than Zymar.</span><sup style="color: #333333;">11 </sup></div> <div style="background-color: #fefefd; color: #333333; margin-bottom: 12px;"> </div> <div style="background-color: #fefefd; color: #333333; margin-bottom: 12px; text-align: justify;"> <span style="font-family: Arial;">Then, in November 2010, Alcon released Moxeza as a successor to Vigamox. In this instance, the concentration of moxifloxacin was not increased. Instead, the company reformulated Vigamox with a new delivery vehicle, xanthan gum. In clinical trials, the xanthan gum facilitated increased corneal penetration of moxifloxacin. Most significantly, the increased drug penetration of Moxeza permitted b.i.d. dosing vs. t.i.d. dosing for Vigamox.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">12</sup></span></div> <div style="background-color: #fefefd; color: #333333; margin-bottom: 12px; text-align: justify;"> <span style="font-family: Arial;">Bausch + Lomb’s release of Besivance (besifloxacin) in 2009 was a significant development in ocular antibiotics. Besifloxacin was developed for the sole purpose of ophthalmic use, and has no systemic counterpart.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">13</sup> This unique aspect could potentially help minimize resistance to the drug over the long term. The drug features a unique chlorine group located at position eight of the quinolone ring, as well as an aminoazepinyl component at the C-7 location, which may enhance activity against gram-positive bacteria.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">14</sup> </span></div> <div style="background-color: #fefefd; color: #333333; margin-bottom: 12px; text-align: justify;"> <span style="font-family: Arial;">Additionally, Besivance uses the DuraSite vehicle (InSite Vision), which prolongs the drug’s contact time on the ocular surface and enhances corneal penetration. Finally, it is important to note that Besivance just received an additional FDA indication for the treatment of conjunctivitis associated with <em style="font-family: Tahoma, Arial, Helvetica, sans-serif;">Pseudomonas aeruginosa</em> in September 2012.</span></div> <div style="background-color: #fefefd; color: #333333; margin-bottom: 12px;"> </div> <div style="text-align: justify;"> <strong><span style="color: brown;">The Effect of BAK </span></strong></div> <span style="font-family: Arial;"><div style="text-align: justify;"> For many years, researchers have debated the potential benefits and limitations of the preservative benzalkonium chloride (BAK) in topical antibiotics. In topical medications that are commonly used long-term, such as glaucoma agents, the presence of BAK has been shown to cause ocular surface inflammation and corneal damage.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">15</sup>However, it has been suggested that, because BAK disrupts the ocular surface, it actually may enhance corneal penetration of the drug. Furthermore, BAK has been shown to increase epithelial permeability and trans-scleral drug delivery.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">16</sup> Currently, Vigamox, Moxeza and Iquix are the few topical fluoroquinolones that do not contain BAK.</div> </span><br /> <div style="background-color: #fefefd; color: #333333; margin-bottom: 12px; text-align: justify;"> <span style="font-family: Arial;">Interestingly, some studies indicated that BAK-preserved Zymar is more effective at targeting methicillin-resistant<em style="font-family: Tahoma, Arial, Helvetica, sans-serif;">Staphylococcus aureus</em> (MRSA) than BAK-free Vigamox in vitro.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">17</sup> Other in vitro research suggested that, while BAK may enhance an antibiotic’s effect, it is cleared by the tears rapidly.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">18</sup> More specifically, the study author noted that the concentration of BAK in the tears is undetectable five minutes after installation.18</span></div> <div style="background-color: #fefefd; color: #333333; margin-bottom: 12px; text-align: justify;"> </div> <div style="margin-bottom: 12px; text-align: -webkit-left;"> </div> <div style="text-align: justify;"> <strong><span style="color: brown;">Bactericidal Resistance</span></strong><span style="font-family: Arial;"> </span></div> <span style="font-family: Arial;"><div style="text-align: justify;"> In addition to corneal penetration, pharmacodynamics (e.g., kill rates, resistance patterns and susceptibility profiles) is another crucial aspect of topical fluoroquinolones. Studies suggest that MICs for fourth-generation fluoroquinolones are lower (better) than second-generation fluoroquinolones for all gram-positive organisms.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">19,20</sup>The MIC90 for ciprofloxacin was lower in gram-negative bacteria compared to the newer-generation fluoroquinolones, and was the most effective against <em style="font-family: Tahoma, Arial, Helvetica, sans-serif;">Pseudomonas</em> among all topical fluoroquinolones tested.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">19,20</sup> </div> </span><br /> <div style="margin-bottom: 12px; text-align: justify;"> <span style="font-family: Arial;">Bactericidal resistance is a result of many factors, including overprescribing and negligent prescribing of antibiotics (e.g., errant use of antibiotics for a viral condition), improper dosing (including patient non-compliance), and widespread use of antibiotics in the livestock industry. Infection by drug-resistant organisms such as MRSA and methicillin-resistant <em style="font-family: Tahoma, Arial, Helvetica, sans-serif;">Staphylococcus epidermidis</em> (MRSE) is a growing concern in the ophthalmic community. According to the Centers for Disease Control and Prevention, 1.5% of the population (4 million Americans) are MRSA carriers.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">21</sup> Patients in nursing care facilities, health care workers, and those who live in communities where skin-to-skin contact is prevalent are at higher risk for MRSA infections.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">21</sup></span></div> <div style="margin-bottom: 12px; text-align: justify;"> <span style="font-family: Arial;">The Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) study was designed to monitor antibiotic susceptibility trends in ocular isolates.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">22</sup> The results indicated that 39% of <em style="font-family: Tahoma, Arial, Helvetica, sans-serif;">S. aureus</em> ocular isolates were methicillin resistant and 38% were fluoroquinolone resistant. Among the coagulase-negative staphylococci isolates sampled from ocular infections, 53% were methicillin resistant and 43% were fluoroquinolone resistant.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">22</sup> This is similar to the original data collected by The Surveillance Network (TSN) from 2001 to 2006, which revealed multidrug-resistant MRSA in ocular isolates.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">23</sup> Of interest, TSN researchers noted that trimethoprim was the most effective agent against MRSA.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">23 </sup></span></div> <div style="margin-bottom: 12px; text-align: justify;"> <span style="font-family: Arial;">Currently, the Ocular Tracking Resistance in the United States Today (TRUST) program is the largest annual, longitudinal, nationwide surveillance of antibiotic resistance. Since the program’s launch in 2005, Ocular TRUST researchers have evaluated the in vitro susceptibility of <em style="font-family: Tahoma, Arial, Helvetica, sans-serif;">Staph.</em>, <em style="font-family: Tahoma, Arial, Helvetica, sans-serif;">Strep.</em>, and <em style="font-family: Tahoma, Arial, Helvetica, sans-serif;">Haemophilus</em> ocular isolates to numerous antibiotics.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">24</sup> The most recent data from Ocular TRUST suggests that just 15% to 30% of MRSA isolates are susceptible to currently available topical fluoroquinolones (Besivance was not evaluated, because it was not yet FDA approved at study initiation).<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">24 </sup></span></div> <div style="margin-bottom: 12px; text-align: justify;"> <span style="font-family: Arial;">The combined results from ARMOR, TSN and Ocular TRUST show that resistance to multiple antibiotics is prevalent among ocular bacterial pathogens. Again, keep in mind that in vitro resistance does not necessarily equate to in vivo resistance. Still, eye care clinicians must consider the potential danger associated with such expanding resistance patterns.</span></div> <br /> <br /> <br /> <br /> <div class="MsoNormal" style="text-align: justify;"> <span style="background: #FEFEFD; color: #333333; font-family: "Tahoma","sans-serif";"><span class="apple-converted-space"><table align="center" bgcolor="#F0C2CC" bordercolor="" cellpadding="" cellspacing="" style="border-collapse: collapse; border: 0px; color: #333333; font-family: Tahoma, Arial, Helvetica, sans-serif; font-size: 12px; margin: 10px;"><tbody> <tr><td style="padding: 3px;"><strong>Recommendations for Fluoroquinolone Use</strong></td></tr> <tr><td style="padding: 3px;"><div style="margin-bottom: 12px;"> <span style="font-family: Arial; font-size: x-small;">• <strong style="font-family: Tahoma, Arial, Helvetica, sans-serif;"><em>Don’t underdose an active infection. </em></strong>Antibiotics with the lowest MIC values and the highest delivery concentration are best suited to eradicate ocular infections. For active infections, dose antibiotics at their recommended frequency to eliminate the bacteria quickly. The greatest risk for the development of antibiotic resistance comes from sustained sub-therapeutic dosing, which doesn’t eradicate the infection but potentially affords it time to mutate. </span></div> <div style="margin-bottom: 12px;"> <span style="font-family: Arial; font-size: x-small;">• <em style="font-family: Tahoma, Arial, Helvetica, sans-serif;"><strong>Be judicious in prophylactic use. </strong></em>When used for surgical prophylaxis, antibiotics can be discontinued sooner than in cases of active infection. A recent study found that repeated fluoroquinolone use after intravitreal injection led to increased rates of resistance.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">30</sup> So, instead of using prophylactic antibiotics, many retinal specialists now are using facemasks and iodine/aseptic techniques during injection to minimize the risks of infection. For infection prevention in cataract surgery, good wound architecture is critical. Today, with femtosecond laser-assisted surgery, wound leaks and consequent endophthalmitis risks may be less likely.</span></div> <div style="margin-bottom: 12px;"> <span style="font-family: Arial; font-size: x-small;">• <strong style="font-family: Tahoma, Arial, Helvetica, sans-serif;"><em>Avoid overprescribing. </em></strong>Improper diagnosis of red eye is a specific instance when topical antibiotics frequently are overprescribed. Too often, pediatricians, urgent care physicians and even optometrists/ophthalmologists prescribe antibiotics for conditions other than bacterial conjunctivitis, when the diagnosis is not clear. Overprescribing propagates bactericidal resistance, so exercise good clinical judgment when using an antibiotic. </span></div> <div style="margin-bottom: 12px;"> <span style="font-family: Arial; font-size: x-small;">• <strong style="font-family: Tahoma, Arial, Helvetica, sans-serif;"><em>Choose an appropriate antibiotic. </em></strong>Consider reserving a “big gun” antibiotic, such as a fourth-generation fluoroquinolone, for the most serious infectious cases. Second-generation fluoroquinolones, aminoglycosides or azithromycin (Azasite, Merck) are alternative antibiotic choices for infections that are not sight threatening. Such alternatives may be effective, and choosing them could potentially limit fourth-generation antibiotic resistance. Also, review the FDA drug safety classification for children and pregnant patients. For example, Azasite may be a good choice for pregnant or nursing mothers because it is a Category B drug.</span></div> <div style="margin-bottom: 12px;"> <span style="font-family: Arial; font-size: x-small;">• <strong style="font-family: Tahoma, Arial, Helvetica, sans-serif;"><em>When in doubt, culture.</em></strong> Smears and cultures are recommended in cases that involve a large infiltrate (>3mm); are chronic in nature or appear unresponsive to broad-spectrum antibiotic therapy; or that exhibit atypical clinical features indicative of fungal, amoebic or <em style="font-family: Tahoma, Arial, Helvetica, sans-serif;">Mycobacterium</em> keratitis. The sensitivities from cultures can help guide appropriate antibiotic selection.</span></div> <div style="margin-bottom: 12px;"> <span style="font-family: Arial; font-size: x-small;">In cases of suspected bacterial keratitis, fourth-generation fluoroquinolones routinely are used off-label and are widely accepted as first-line therapy. Depending on its location and severity, microbial keratitis can be a sight-threatening condition. For central or severe keratitis, a loading dose (q15m for the first hour) followed by frequent applications (q1h around the clock) is recommended. </span></div> <div style="margin-bottom: 12px;"> <span style="font-family: Arial; font-size: x-small;">For drug-resistant pathogens, such as MRSA or MRSE, fluoroquinolones may not prove effective. If a bacterial infection is not clinically responsive to aggressive treatment with a fluoroquinolone, suspect MRSA/MRSE. Consider treatment with fortified vancomycin, trimethoprim or sulfacetamide.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">31</sup> In these instances, be certain to obtain cultures in an effort to select the most effective antibiotic. Additional therapeutic options that may be effective against MRSA/MRSE include bacitracin ointment, cefazolin injection and oral linezolid. Concurrent use of oral rifampin and linezolid have been shown to be more effective in the treatment of preseptal cellulitis/cutaneous infections than intravenous vancomycin.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">32 </sup></span></div> <div style="margin-bottom: 12px;"> <span style="font-family: Arial; font-size: x-small;">• <strong style="font-family: Tahoma, Arial, Helvetica, sans-serif;"><em>Be wary of </em>Mycobacterium<em>. </em></strong>Regarding refractive surgery, infection rates fortunately are low. But, if an infection occurs, atypical <em style="font-family: Tahoma, Arial, Helvetica, sans-serif;">Mycobacterium</em> infiltrates may be of greatest concern. Although rare, <em style="font-family: Tahoma, Arial, Helvetica, sans-serif;">Mycobacterium</em>are found in ultrasound water baths used for instrument processing or in surgical field moisture. In any confirmed case of <em style="font-family: Tahoma, Arial, Helvetica, sans-serif;">Mycobacterium</em> <em style="font-family: Tahoma, Arial, Helvetica, sans-serif;">chelonae</em> infection, researchers at Johns Hopkins recommend 500mg clarithromycin b.i.d., topical tobramycin and a fourth-generation fluoroquinolone.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">33 </sup></span></div> <div style="margin-bottom: 12px;"> <span style="font-family: Arial; font-size: x-small;">• <strong style="font-family: Tahoma, Arial, Helvetica, sans-serif;"><em>Consider the cost. </em></strong>Because of rising medication prices, patients are sometimes forced to use generic antibiotics in lieu of branded medications. Newer-generation fluoroquinolones have the broadest antimicrobial spectrum. But, if patients cannot afford these, which generic agent is best? To date, no studies offer a real solution to this question, and practitioners are faced with the ongoing dilemma of cost vs. efficacy. </span></div> <div style="margin-bottom: 12px;"> <span style="font-family: Arial; font-size: x-small;">However, generic trimethoprim-polymyxin B should be considered when there is a risk of MRSA. Despite being an older drug, more than 90% of MRSA isolates were susceptible to trimethoprim in vitro.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">28</sup> Also, the second-generation fluoroquinolones are cost effective, and have a broad spectrum of coverage. They are a good choice if a generic is needed. Regardless, educate patients about the potential risks associated with having to choose between the lower cost of generic medications and the therapeutic superiority of branded drugs.</span></div> </td></tr> </tbody></table> </span></span></div> <div class="MsoNormal" style="text-align: justify;"> <span style="background: #FEFEFD; color: #333333; font-family: "Tahoma","sans-serif";"><span class="apple-converted-space"></span></span></div> <div id="content_container" style="font-family: Tahoma, Arial, Helvetica, sans-serif; position: relative; text-align: -webkit-left;"> <div style="font-size: 12px; margin-bottom: 12px;"> <span style="font-family: Arial; font-size: x-small;"><span style="color: brown; font-family: Tahoma, Arial, Helvetica, sans-serif;"><strong><span style="font-size: small;">Use in Surgical Prophylaxis</span></strong></span> <br style="font-family: Tahoma, Arial, Helvetica, sans-serif;" />Topical antibiotics are used routinely for infection prevention in all forms of ocular surgery. The discussion about appropriate use of prophylactic antibiotics is a hot topic among eye care professionals due to increased resistance patterns. Some studies have reported increased endophthalmitis rates since 2000 despite prophylactic antibiotic use.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">25</sup></span></div> <div style="font-size: 12px; margin-bottom: 12px;"> <span style="font-family: Arial; font-size: x-small;">There are several possible reasons why endophthalmitis is on the rise. For example, more surgeons perform cataract surgery using sutureless, clear corneal incisions, which are more prone to leakage. Additionally, intravitreal anti-VEGF and steroidal injections are being administered more frequently for the treatment of macular degeneration and diabetic eye disease. </span></div> <div style="font-size: 12px; margin-bottom: 12px;"> <span style="font-family: Arial; font-size: x-small;">Most cases of postoperative endophthalmitis are due to <em style="font-family: Tahoma, Arial, Helvetica, sans-serif;">S. epidermidis</em>, followed by <em style="font-family: Tahoma, Arial, Helvetica, sans-serif;">S. aureus</em>.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">26</sup> Further, epidemiologic evidence suggests that MRSA is responsible for approximately 3% of all endophthalmitis cases.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">26 </sup></span></div> <div style="font-size: 12px; margin-bottom: 12px;"> <span style="font-family: Arial; font-size: x-small;">The overall rate of endophthalmitis after uncomplicated cataract surgery in patients who received prophylactic treatment with gatifloxacin and moxifloxacin was 0.07%.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">26</sup> Another study found a similar endophthalmitis rate for those who received gatifloxacin and moxifloxacin (0.056%), but a higher incidence in patients who were treated with ciprofloxacin and ofloxacin (0.197%).<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">27</sup></span></div> <div style="font-size: 12px; margin-bottom: 12px;"> <span style="font-family: Arial; font-size: x-small;">These data suggest that the fourth-generation fluoroquinolones are more effective against gram-positive organisms and may be the superior choice for surgical endophthalmitis prevention. Fortunately, the risk of post-surgical infection is extremely rare. And ultimately, the low rates of endophthalmitis also make it exceedingly difficult to compare the prophylactic efficacy of different antibiotics exhaustively.</span></div> <div style="font-size: 12px; margin-bottom: 12px;"> <span style="font-family: Arial; font-size: x-small;">During the last few years, intracameral antibiotics have been evaluated for use in ocular surgery. A recent study by the European Society of Cataract & Refractive Surgeons (ESCRS) showed that cefuroxime injection can reduce endophthalmitis risk in cataract surgery.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">28</sup> Further, intracameral injections have the potential to help reduce postoperative patient noncompliance/drop confusion, and could be more cost effective than topical anti-infective use. </span></div> <div style="font-size: 12px; margin-bottom: 12px;"> <span style="font-family: Arial; font-size: x-small;">The primary barrier to wider adoption of intracameral antibiotic administration in the United States is the lack of a commercially available drug. Cefuroxime, for example, must be compounded manually, which exposes the patient to bacterial contamination and toxic anterior segment syndrome. </span></div> <div style="font-size: 12px; margin-bottom: 12px;"> <span style="font-family: Arial; font-size: x-small;">In lieu of cefuroxime, some American cataract surgeons are using intracameral administration of moxifloxacin and vancomycin to reduce or eliminate postoperative antibiotic drops.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">29</sup> However, we must be cautious in recommending this practice––especially considering that, in the ESCRS study, patients still used levofloxacin postoperatively for one week.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">28</sup></span></div> <div style="font-size: 12px; margin-bottom: 12px;"> <span style="font-family: Arial; font-size: x-small;"><br style="font-family: Tahoma, Arial, Helvetica, sans-serif;" />Newer-generation fluoroquinolones have become the topical antibiotic of choice in the prevention and treatment of ocular infections due to their high tissue concentrations, low MIC rates and broad spectrum of coverage. Nonetheless, eye care providers must be educated about the rising rates of increased fluoroquinolone resistance in certain pathogens, including MRSA. </span></div> <div style="font-size: 12px; margin-bottom: 12px;"> <span style="font-family: Arial; font-size: x-small;">We should make every effort to ensure an accurate diagnosis of bacterial infections to avoid unnecessary overuse of antibiotics. In cases where topical antibiotics are indicated, use them aggressively for a defined period. For infections that do not respond, perform cultures. </span></div> <div style="font-size: 12px; margin-bottom: 12px;"> <span style="font-family: Arial; font-size: x-small;">Today, we are fortunate to have several extremely effective antibiotic agents in our armamentarium. But, to prevail in the battle against ocular infection, we must use these drugs in a judicious capacity to limit further bactericidal resistance. </span></div> <div style="font-size: 12px; margin-bottom: 12px;"> <em><span style="font-family: Arial; font-size: x-small;">Dr. Muckley is the director of optometric services at Northeast Ohio Eye Surgeons in Kent and Stow, Ohio. She has no financial interest in any of the products mentioned. 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Clinical Ophthalmic Pharmacology. Boston, MA: Little Brown & Co;1987:1-52.<br />7. Holland EJ. Human ocular concentrations following topical fluoroquinolone adminstration relative to susceptibility of ocular pathogens. Invest Ophthalmol Vis Sci 2006;47: E-Abstract 1881.<br />8. Donnenfeld ED. Human aqueous humor concentrations of besifloxacin, moxifloxacin, and gatifloxacin after topical ocular application. J Cat Refract Surg. 2011Jun;37(6):1082-89.<br />9. McCaulley JP. Fourth generation fluoroquinolones penetration into aqueous humor in humans. Ophthalmology. 2006 June;113(6):955-59.<br />10. Woodcock J, Toigo T. Iquix. New Drug Application: Clinical Review. March 1, 2004. Available at:<a href="http://www.accessdata.fda.gov/drugsatfda_docs/nda/2004/NDA%2021-571_Iquix_AdminCorres.pdf" style="color: #003366;" target="_parent">www.accessdata.fda.gov/drugsatfda_docs/nda/2004/NDA%2021-571_Iquix_AdminCorres.pdf</a>. Accessed November 17, 2012.<br />11. Lloyd RA. Zymaxid. New Drug Application: Clinical Review. July 30, 2009. Available at:<a href="http://www.fda.gov/downloads/Drugs/DevelopmentApprovalProcess/DevelopmentResources/UCM214207.pdf" style="color: #003366;" target="_parent">www.fda.gov/downloads/Drugs/DevelopmentApprovalProcess/DevelopmentResources/UCM214207.pdf</a>. Accessed November 17, 2012.<br />12. Lindstrom R, Lane S, Cottingham A, et al. Conjunctival concentrations of a new ophthalmic solution formulation of moxifloxacin 0.5% in cataract surgery patients. J Ocul Pharmacol Ther. 2010 Dec;26(6):591-5.<br />13. Murphy MD, Mathis LL. Besivance. Executive Summary: Best Pharmaceuticals for Children Act Drug Use Review in the Pediatric Population. January 5, 2011. Available at:<a href="http://www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterials/PediatricAdvisoryCommittee/UCM255069.pdf" style="color: #003366;" target="_parent">www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterials/PediatricAdvisoryCommittee/UCM255069.pdf</a>. Accessed November 17, 2012.<br />14. Ward KW, Lepage JF, Driot JY. Nonclinical pharmacodynamics, pharmacokinetics, and safety of BOL-303224-A, a novel fluoroquinolone antimicrobial agent for topical ophthalmic use. J Ocul Pharmacol Ther. 2007 Jun;23(3):243-56.<br />15. Noecker RJ, Herrygers LA, Anwaruddin R. Corneal and conjunctival changes caused by commonly used glaucoma medications. Cornea. 2004 Jul;23(5):490-6.<br />16. Okabe K, Kimura H, Okabe J, et al. Effect of benzalkonium chloride on transscleral drug delivery. Invest Ophthalmol Vis Sci. 2005 Feb;46(2):703-8.<br />17. Blondeau JM, Borsos S, Hesje CK. Antimicrobial efficacy of gatifloxacin and moxifloxacin with and without benzalkonium chloride compared with ciprofloxacin and levofloxacin against methicillin-resistant Staphylococcus aureus. J Chemother. 2007 Apr;19(2):146-51.<br />18. Friedlaender MH, Breshears D, Amoozgar B, et al. The dilution of benzalkonium chloride (BAK) in the tear film. Adv Ther. 2006 Nov-Dec;23(6):835-41.<br />19. Oliveira AD, D'Azevedo PA, Francisco W. In vitro activity of fluoroquinolones against ocular bacterial isolates in Sao Paulo, Brazil. Cornea. 2007 Feb;26(2):194-8.<br />20. Kowalski RP, Yates KA, Romanowski E, et al. An ophthalmologist's guide to understanding antibiotic susceptibility and minimum inhibitory concentration data. Ophthalmology. 2005 Nov;112(11):1987.<br />21. Gorwitz RJ. Understanding the success of methicillin-resistant Staphylococcus aureus strains causing epidemic disease in the community. J Infect Dis. 2008 Jan 15;197(2):179-82.<br />22. Haas W, Pillar CM, Torres M, et al. Monitoring antibiotic resistance in ocular microorganisms: Results from the Antibiotic Resistance Monitoring in Ocular micRorganisms (ARMOR) 2009 surveillance study. Am J Ophthalmol. 2011 Oct;152(4):567-574.e3.<br />23. Asbell PA, Sahm DF, Shaw M, et al. Increasing prevalence of methicillin resistance in serious ocular infections caused by Staphylococcus aureus in the United States: 2000 to 2005. J Cataract Refract Surg. 2008 May;34(5):814-8.<br />24. Asbell PA, Colby KA, Deng S. Ocular TRUST: nationwide antimicrobial susceptibility patterns in ocular isolates. Am J Ophthalmol. 2008 Jun;145(6):951-8.<br />25. Colleaux KM, Hamilton WK. Effect of prophylactic antibiotics and incision type on the incidence of endophthalmitis after cataract surgery. Can J Ophthalmol. 2000 Dec;35(7):373-8.<br />26. Moshirfar M, Feiz V, Vitale AT, et al. Endophthalmitis after uncomplicated cataract surgery with the use of fourth-generation fluoroquinolones: a retrospective observational case series. Ophthalmology. 2007 Apr;114(4):686-91.<br />27. Jensen MK, Fiscella RG, Moshirfar M, Mooney B. Third- and fourth-generation fluoroquinolones: retrospective comparison of endophthalmitis after cataract surgery performed over 10 years. J Cataract Refract Surg. 2008 Sep;34(9):1460-7.<br />28. Barry P, Seal DV, Gettinby G, et al. ESCRS study of prophylaxis of postoperative endophthalmitis after cataract surgery: Preliminary report of principal results from a European multicenter study. J Cataract Refract Surg. 2006 Mar;32(3):407-10.<br />29. Shorstein NH, Winthrop KL, Herrinton LJ. Decreased postoperative endophthalmitis rate after institution of intracameral antibiotics in a Northern California eye department. J Cataract Refract Surg. 2012 Oct 1. [Epub ahead of print]<br />30. Milder E. Changes in antibiotic resistance patterns of conjunctival flora due to repeated use of topical antibiotics after intravitral injection. Ophthalmology. 2012 Jul;119(7):1420-4.<br />31. Asbell PA. Ocular TRUST 3: Ongoing Longitudinal Surveillance of Antimicrobial Susceptibility in Ocular Isolates. Poster presented at: Annual Meeting of the American Society of Cataract and Refractive Surgery: April 3-8, 2009; San Francisco.<br />32. Bababeygy SR, Silva RA, Sun Y, Jain A. Rifampin and linezolid in the treatment of methicillin-resistant Staphylococcus aureus preseptal cellulitis. Ophthal Plast Reconstr Surg. 2009 May-Jun;25(3):227-8.<br />33. Hoffmann CJ. Mycobacterium chelonae. Johns Hopkins Antibiotic (ABX) Guide. Available at:<a href="http://www.hopkinsguides.com/hopkins/ub/view/Johns_Hopkins_ABX_Guide/540364/all/Mycobacterium+chelonae" style="color: #003366;" target="_parent">www.hopkinsguides.com/hopkins/ub/view/Johns_Hopkins_ABX_Guide/540364/all/Mycobacterium+chelonae</a>. Accessed November 17, 2012.</span> </span></div> <div style="font-size: 12px;"> <span style="font-family: Arial; font-size: x-small;"><br /></span></div> </div> <br /> </div>

¿Estamos ganando terreno sobre la infección ocular?

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Sepa cómo hacer ventas a través del celular en una tienda usando la billetera electronica

<div dir="ltr" style="text-align: left;" trbidi="on"> Visualización optima 1600x900 pixel Comenta.esta.publicación<br /> <br /> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjSil2yqaSlq87UsQtntyFXZN2hWFL64E2hntI7ZWfKtYDS9lA5AiH9d0OFn6CS63KNvzipARya8i3Z1bmvNsaIp3yNVa-AKDHaOb-cxK9klqjxWSjJrpiIZlBDXbIz_qG7b_JNnhywPu0/s1600/40564_ciencia-y-tecnologia.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="172" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjSil2yqaSlq87UsQtntyFXZN2hWFL64E2hntI7ZWfKtYDS9lA5AiH9d0OFn6CS63KNvzipARya8i3Z1bmvNsaIp3yNVa-AKDHaOb-cxK9klqjxWSjJrpiIZlBDXbIz_qG7b_JNnhywPu0/s320/40564_ciencia-y-tecnologia.jpg" width="320" /></a></div> <br /> <br /> <br /> <div style="text-align: justify;"> <span style="font-size: small;">El dinero electrónico pronto será una realidad en el Perú, pues la legislación para regular su uso de forma masiva está lista para ser debatida por el pleno del Congreso. En la actualidad este sistema funciona solo en algunas bodegas de Lima a manera de prueba.</span></div> <div style="text-align: justify;"> <span style="font-size: small;">Así, <b>dentro de poco, todos podremos pagar, comprar y enviar dinero usando nuestro celular como una billetera electrónica,</b> sea este un smartphone de última generación o un modelo antiguo que solo envía mensajes de texto.<br /><br />La empresa Yellow Pepper <b>realizó una demostración a RPP Noticias de la forma en que se usará el celular para realizar una compra en una tienda a través de un terminal POS</b>, que actualmente se usa para pagos con tarjetas.<br /><br />Con este sistema, el celular emite un código único que deberá ser ingresado en el POS, el cual es validado por el sistema y el dinero es debitado de su billetera electrónica.</span></div> <div style="text-align: justify;"> <br /></div> <h1 class="txt_t32-gris" style="text-align: justify;"> <span style="font-size: small;">SBS: Norma sobre dinero electrónico facilitará inclusión financiera</span></h1> <h1 class="txt_t32-gris" style="text-align: justify;"> <span style="font-size: small;"> </span></h1> <div style="text-align: justify;"> <span style="font-size: small;"> La Superintendencia de Banca, Seguros y AFP (SBS) señaló que <b>la Ley que regula las características básicas del dinero electrónico, promulgada este miércoles por el presidente Ollanta Humala, facilitará la inclusión financiera en el país</b>. <br /><br />Indicó que la norma tiene como objetivo promover el uso de dispositivos electrónicos como canales de acceso a servicios financieros, sobre todo para los sectores de la población que actualmente no son atendidos por el sistema o que se encuentran alejados geográficamente.</span></div> <div style="text-align: justify;"> <span style="font-size: small;">La promulgación de esta <b>norma permitirá que mediante el uso de un celular simple o con tarjetas pre pago, las personas puedan hacer pagos y transferencias de manera segura de la misma forma que lo harían con efectivo.  </b></span></div> <div style="text-align: justify;"> <span style="font-size: small;">"Este impacto será importante teniendo en cuenta el nivel de penetración que los servicios de telefonía móvil tienen en el país (más de 24 millones de líneas) y el crecimiento de la red de cajeros corresponsales del sistema financiero (más de 13 mil)", indicó la SBS en un comunicado.</span></div> <div style="text-align: justify;"> <span style="font-size: small;">Sostuvo que para facilitar este servicio la ley establece una regulación mínima a efectos de promover el desarrollo de productos y servicios que permitan lograr la inclusión financiera.</span></div> <div style="text-align: justify;"> <span style="font-size: small;">La norma precisa que el dinero electrónico es almacenado en un soporte electrónico (como un celular o tarjeta pre pago), es aceptado de manera general como medio de pago, es emitido por un valor igual a los fondos recibidos y puede ser convertido nuevamente a efectivo por el saldo que mantenga el titular.</span></div> <div style="text-align: justify;"> <span style="font-size: small;">También precisa que este dinero almacenado no constituye depósito y no genera intereses.</span></div> <div style="text-align: justify;"> <span style="font-size: small;">De igual forma, con la finalidad de garantizar servicios de pago seguros y confiables para la población, la ley establece que <b>los servicios de dinero electrónico serán prestados solo por empresas que estén bajo el ámbito de supervisión de la SBS,</b> las cuales se encuentran sujetas, entre otras, a estándares y normas de gestión de riesgo operacional (tecnológico), transparencia de información al usuario y prevención del lavado de activos y financiamiento del terrorismo.</span></div> <div style="text-align: justify;"> <span style="font-size: small;">Además, para generar competencia y con ello comisiones menores se señala que el servicio de emisión de dinero electrónico podrá ser brindado por las empresas de operaciones múltiples ya existentes, como los bancos, financieras, cajas municipales y rurales de ahorro y crédito (CMAC y CRAC), cajas municipales de crédito popular y Entidades de Desarrollo a la Pequeña y Micro Empresa (Edpyme).</span></div> <div style="text-align: justify;"> <span style="font-size: small;">Igualmente, por un nuevo tipo de empresa, también supervisada por la SBS, denominada empresa emisora de dinero electrónico. <br /><br /> Para resguardar los recursos obtenidos de la emisión de dinero electrónico, la ley establece que <b>los emisores deben constituir fideicomisos por el valor del dinero electrónico emitido y, asimismo, la SBS regulará otras garantías para proteger dichos fondos</b>.</span></div> <div style="text-align: justify;"> <span style="font-size: small;">En tanto, la información del usuario del dinero electrónico y de las operaciones que realice estará sujeta a la Ley de Protección de Datos Personales.</span></div> <div style="text-align: justify;"> <span style="font-size: small;">Finalmente, la SBS indicó que a efectos de lograr la masificación del dinero electrónico en condiciones competitivas, la ley establece que los servicios de telecomunicaciones que se utilicen para la prestación de servicios financieros (por ejemplo celulares) deberán ser brindados en igualdad de condiciones a todas las empresas que provean estos servicios financieros.</span></div> <div style="text-align: justify;"> <br /></div> <h1 class="txt_t32-gris" style="text-align: justify;"> <span style="font-size: small;">SBS: ´Monto mensual máximo de dinero electrónico será de S/.3.700´</span></h1> <h1 class="txt_t32-gris" style="text-align: justify;"> <span style="font-size: small;"> </span></h1> <h1 class="txt_t32-gris" style="text-align: justify;"> <span style="font-size: small;"><b>El monto máximo de dinero electrónico que podrán usar en un mes los peruanos cuando empiece a funcionar el sistema será de una Unidad Impositiva Tributaria (UIT), es decir S/.3.700</b>, así lo indicó el superintendente adjunto de Riesgos de la Superintendencia de Banca, Seguros y AFP (SBS), Alejandro Medina.<br /><br />Vale indicar que <b>el valor de una UIT varía a inicio de cada año, por lo que monto a usar será modificado con el transcurrir de los años.</b><br /><br />“Hoy día tenemos un símil en los depósitos bancarios implicados, lo cual ya existe y es un producto que probablemente sea lo primero que vea el ciudadano en los próximos meses”, manifestó en <b>RRP Noticias.</b><br /><br />Señaló que <b>las transacciones hechas de manera electrónica estarán resguardadas por el seguro de depósitos, siempre y cuando estén relacionadas a una cuenta bancaria. </b><br /><br />En caso que el movimiento sea hecho desde los fondos de una empresa de dinero electrónico, <b>el capital estará protegido a través de un fideicomiso o un respaldo continuo en los bancos.</b><br /><br />“Lo que se busca es asilar completamente la responsabilidad de la empresa que emite con los fondos que administra”, puntualizó.<br /><br /><b>Una vez instaurado el sistema las personas no deberían cargar grandes cantidades de dinero en su soporte móvil (ya sea teléfono celular o tarjeta pre pago)</b>, afirmó.<br /><br />“El dinero electrónico lo que busca es el monto que se tiene en la billetera o un monedero y ninguna persona prudente lleva en sus bolsillos grandes cantidades de dinero”, refirió.<br /><br />Por otro lado <b>el superintendente aseguró que las personas que manejarán su dinero electrónico a través de su teléfono móvil no tendrán riesgo de desfalco en caso de robo del aparato, pues existen mecanismo de seguridad ligados a la transacción financiera.</b><br /><br />En ese sentido exhortó a la población a <b>no guardar sus claves en las memorias de sus teléfonos.</b><br /><br /><b>Tarjetas </b><br />Finalmente graficó a la población que <b>el dinero electrónico que se usará a mediados de año mediante tarjetas es similar a una tarjeta del Metropolitano o del Tren Eléctrico</b>, con la diferencia que estos plásticos solo pueden ser usados en las respectivas estaciones. </span></h1> <div style="text-align: justify;"> <div style="text-align: justify;"> <span style="color: #351c75;"><b><b>¿Cómo usar la billetera móvil?</b></b></span></div> <div style="text-align: justify;"> <span style="color: #351c75;"><b>La billetera electrónica Wanda solamente funcionará –en un principio- con los celulares de Movistar, ya sean smartphones o teléfonos básicos y el sistema opera de manera similar al envío de los mensajes de texto. Los pasos para empezar a operar son los siguientes:<br /><br />1.- Acudir a cualquiera de los agentes del BCP o puntos de recargas de Movistar con tu DNI y afiliar gratis su celular al sistema de billetera móvil de Wanda. <br /><br />2.- Depositar el monto de dinero que se desee utilizar y crear un código pin personal para tener seguridad al momento de realizar transacciones.<br /><br />3.- Para ingresar al sistema debe marcar desde el celular *122# y escoger en el menú el tipo de operación, ya sea pagos de servicios, transferencias o consultas. Si decide realizar una transferencia a una persona, debe colocar el número de celular que recibirá el pago.<br /><br />4.- Al realizar cada operación recibirá un mensaje de texto de confirmación de la recepción del dinero y aparecerá el saldo restante en el celular.</b></span></div> </div> <h1 class="txt_t32-gris"> <span style="color: #073763;">  </span></h1> <div style="text-align: justify;"> <br /></div> </div>

Sepa cómo hacer ventas a través del celular en una tienda usando la billetera electronica

Visualización optima 1600x900 pixel Comenta.esta.publicación El dinero electrónico pronto será una realidad en el Perú, pues la le...

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Una técnica que congela los tumores puede servir contra el cáncer de mama

<div dir="ltr" style="text-align: left;" trbidi="on"> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3jdaVFo9wMFN45ImsK_FD8RIbqFpmGTninjAm7Kn8T2WRJGfHfJ4jGEw7iKUHMdKNz0Jwj0seO13sxvmSJ_jddBHrOImoX7R9is1EFwfHShyphenhyphenN8aD9kQRr8oh3K8jrsQTYqJVpWt-jchM/s1600/123.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3jdaVFo9wMFN45ImsK_FD8RIbqFpmGTninjAm7Kn8T2WRJGfHfJ4jGEw7iKUHMdKNz0Jwj0seO13sxvmSJ_jddBHrOImoX7R9is1EFwfHShyphenhyphenN8aD9kQRr8oh3K8jrsQTYqJVpWt-jchM/s1600/123.jpg" /></a></div> <div class="separator" style="clear: both; text-align: center;"> <br /></div> <div class="separator" style="clear: both; text-align: center;"> </div> <div style="background-color: white; border: 0px; color: #333333; font-family: arial; line-height: 21px; margin-bottom: 20px; outline: 0px; padding: 0px; text-align: start;"> </div> <div style="text-align: justify;"> <strong style="border: 0px; margin: 0px; outline: 0px; padding: 0px;">PAOLA MONTES ITURRIZAGA</strong></div> <div style="text-align: justify;"> El Comercio</div> <br /> <div style="background-color: white; border: 0px; color: #333333; font-family: arial; line-height: 21px; margin-bottom: 20px; outline: 0px; padding: 0px; text-align: justify;"> Una nueva técnica para eliminar tumores mamarios cumple de sobra con uno de los objetivos de la cirugía moderna: obtener buenos resultados mientras se reduce la invasión por cirugía en el cuerpo del paciente.</div> <div style="background-color: white; border: 0px; color: #333333; font-family: arial; line-height: 21px; margin-bottom: 20px; outline: 0px; padding: 0px; text-align: justify;"> La crioablación es un procedimiento por el cual se convierte el tumor en una bola de hielo para eliminarlo. Fue diseñado hace pocos años por científicos de la <a href="http://www.umich.edu/" style="border: 0px; color: #003871; margin: 0px; outline: 0px; padding: 0px;" target="_blank">Universidad de Michigan</a> (EE.UU.), pero la compañía israelí Ice Cure Medical perfeccionó la técnica y, para ello, creó un dispositivo llamado IceSense 3.</div> <div style="background-color: white; border: 0px; color: #333333; font-family: arial; line-height: 21px; margin-bottom: 20px; outline: 0px; padding: 0px; text-align: justify;"> Esta máquina permite realizar una cirugía con cicatrices imperceptibles, capaz de ser realizada en el consultorio y ya no en una sala de operaciones.</div> <div style="background-color: white; border: 0px; color: #333333; font-family: arial; line-height: 21px; margin-bottom: 20px; outline: 0px; padding: 0px; text-align: justify;"> El frío produce un efecto anestésico, por ello el paciente no experimenta dolor durante y después de la sesión.</div> <div style="background-color: white; border: 0px; color: #333333; font-family: arial; line-height: 21px; margin-bottom: 20px; outline: 0px; padding: 0px; text-align: justify;"> El médico utiliza anestesia local para que el paciente no sienta la inserción de la delgada aguja. Gracias al ultrasonido, una ecografía mostrará en pantalla el interior de la mama para guiar a la fina aguja hasta el fibroadenoma (tumor benigno de mama).</div> <div style="background-color: white; border: 0px; color: #333333; font-family: arial; line-height: 21px; margin-bottom: 20px; outline: 0px; padding: 0px; text-align: justify;"> La aguja, que se parece a la usada para practicar una biopsia, bombea nitrógeno líquido en el tumor para congelarlo a una temperatura tan baja (-170 °C) que produce su destrucción.</div> <div style="background-color: white; border: 0px; color: #333333; font-family: arial; line-height: 21px; margin-bottom: 20px; outline: 0px; padding: 0px; text-align: justify;"> “El tumor, así como cualquier parte de nuestro cuerpo, está constituido por agua; y el agua se congela. En el ámbito vascular, se produce una constricción, y al no haber irrigación, el tejido muere debido al congelamiento”, explicó a <strong style="border: 0px; margin: 0px; outline: 0px; padding: 0px;">El Comercio</strong> el doctor Luis Riva, oncólogo de la clínica Internacional y presidente de la Junta Directiva de la Sociedad Peruana de Oncología.</div> <div style="background-color: white; border: 0px; color: #333333; font-family: arial; line-height: 21px; margin-bottom: 20px; outline: 0px; padding: 0px; text-align: justify;"> Debido a la efectividad mostrada por el sofisticado dispositivo, en EE.UU. se han iniciado los ensayos clínicos para comprobar la eficiencia de IceSense3 en pacientes con cáncer de mama.</div> <div style="background-color: white; border: 0px; color: #333333; font-family: arial; line-height: 21px; margin-bottom: 20px; outline: 0px; padding: 0px; text-align: justify;"> La sospecha de que el método podría ser efectivo para el cáncer de mama también llevó al doctor Eisuke Fukuma, presidente del Centro del Seno del Kameda Medical Center en Kamogawa (Japón) a realizar en junio del 2012 las primeras pruebas con pacientes cuyos tumores malignos estaban aún pequeños (no más de 1 centímetro).</div> <div style="background-color: white; border: 0px; color: #333333; font-family: arial; line-height: 21px; margin-bottom: 20px; outline: 0px; padding: 0px; text-align: justify;"> En los resultados se observó que los tumores fueron destruidos en su totalidad, lo que podría significar un paso importante hacia la eliminación de tumores de cáncer de mama sin requerir las cirugías abiertas de extirpación. Además, se espera la remisión de los tumores malignos, tal y como se ha reportado con los fibroadenomas.</div> <div style="background-color: white; border: 0px; color: #333333; font-family: arial; line-height: 21px; margin-bottom: 20px; outline: 0px; padding: 0px; text-align: justify;"> Aunque IceSense 3 pueda entusiasmar a médicos y pacientes, el doctor Riva sugiere ser cautelosos: “Se debe considerar, sí, pero hay que recordar que es un elemento que está en fase de ensayo clínico y no es un estándar. Se trata de un reemplazo a la cirugía inicial, y esto no quita que el paciente continúe los tratamientos estándares de quimioterapia o radioterapia”.</div> <div style="background-color: white; border: 0px; color: #333333; font-family: arial; line-height: 21px; margin-bottom: 20px; outline: 0px; padding: 0px; text-align: justify;"> Debido a que el tumor se elimina in situ y no se extirpa, los desarrolladores indican que este será asimilado por el propio organismo mediante un proceso natural y seguro.</div> <div style="background-color: white; border: 0px; color: #333333; font-family: arial; line-height: 21px; margin-bottom: 20px; outline: 0px; padding: 0px; text-align: justify;"> “Es cierto que los tumores se absorben con éxito luego de la crioablación porque prácticamente es tejido muerto, y el cuerpo lo procesa bien”, finaliza el doctor Riva.</div> <div style="background-color: white; border: 0px; color: #333333; font-family: arial; line-height: 21px; margin-bottom: 20px; outline: 0px; padding: 0px; text-align: justify;"> Además de su principal objetivo –que es la destrucción del tumor– la técnica IceSense 3 ofrece otras ventajas. Una es que la fina aguja desarrollada permite un mejor control de la cantidad de nitrógeno líquido que se utilizará, asegurándole al especialista que el tejido sano no será dañado. En cuanto a la cicatrización, al no requerirse una sutura, el paciente abandona el consultorio solo con un pequeño parche sobre la zona de la pequeña incisión por donde ingresó la aguja.</div> <div style="background-color: white; border: 0px; color: #333333; font-family: arial; line-height: 21px; margin-bottom: 20px; outline: 0px; padding: 0px; text-align: justify;"> La <a href="http://elcomercio.pe/tag/242831/fda" style="border: 0px; color: #003871; margin: 0px; outline: 0px; padding: 0px;" target="_blank">Agencia de Alimentos y Medicamentos</a> (FDA) de Estados Unidos aprobó la crioablación para eliminar el fibroadenoma de mama en el 2010.</div> <br /> Visualización optima 1600x900 pixel Comenta.esta.publicación</div>

Una técnica que congela los tumores puede servir contra el cáncer de mama

PAOLA MONTES ITURRIZAGA El Comercio Una nueva técnica para eliminar tumores mamarios cumple de sobra con uno de los objetivos...

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Un incendio afectó un edificio en el Centro de Lima afectando a varias ópticas

<div dir="ltr" style="text-align: left;" trbidi="on"> Visualización optima 1600x900 pixel Comenta.esta.publicación<br /> <br /> <span style="background-color: white; font-family: Arial, Helvetica, sans-serif; font-size: 14px; line-height: 21px;">Los bomberos lograron controlas las llamas luego de mas de una hora de ardua lucha.</span><br /> <span style="background-color: white;"><span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: 14px; line-height: 21px;">varias ópticas en el centro de lima fueron afectadas con el cierre temporal de sus locales </span></span></span><br /> <span style="background-color: white;"><span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: 14px; line-height: 21px;">y otras cerraron por prevención.</span></span></span><br /> <span style="background-color: white;"><span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: 14px; line-height: 21px;"><br /></span></span></span> <br /> <div class="separator" style="clear: both; text-align: center;"> <iframe allowfullscreen="allowfullscreen" frameborder="0" height="266" mozallowfullscreen="mozallowfullscreen" src="https://www.youtube.com/embed/aoYvL01A1RY?feature=player_embedded" webkitallowfullscreen="webkitallowfullscreen" width="320"></iframe></div> <br /> <span style="background-color: white;"><span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: 14px; line-height: 21px;"><br /></span></span></span> <span style="background-color: white;"><span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: 14px; line-height: 21px;"><br /></span></span></span> <span style="background-color: white; font-family: Arial, Helvetica, sans-serif; font-size: 14px; line-height: 21px;"><br /></span> <span style="background-color: white; font-family: Arial, Helvetica, sans-serif; font-size: 14px; line-height: 21px;"><br /></span> <span style="background-color: white; font-family: Arial, Helvetica, sans-serif; font-size: 14px; line-height: 21px;"><br /></span></div>

Un incendio afectó un edificio en el Centro de Lima afectando a varias ópticas

Visualización optima 1600x900 pixel Comenta.esta.publicación Los bomberos lograron controlas las llamas luego de mas de una hora de ardua...

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Consumo de viagra aumenta pero uso constante afecta la visión

<div dir="ltr" style="text-align: left;" trbidi="on"> Visualización optima 1600x900 pixel Comenta.esta.publicación<br /> <br /> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9aZYZNtFa4u_hDcqxPieXGiuexSdGdytWI5KZ1WQtHVhGl1bSKQBy5kQGEseOKOzweP3uNcMuC0dOXIx4jCwVbjGJ4A8jcP75NUIJCaK6GwjVqkE_JaGDzNwV2emRnW-bP7umRqDwF7A/s1600/123456.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9aZYZNtFa4u_hDcqxPieXGiuexSdGdytWI5KZ1WQtHVhGl1bSKQBy5kQGEseOKOzweP3uNcMuC0dOXIx4jCwVbjGJ4A8jcP75NUIJCaK6GwjVqkE_JaGDzNwV2emRnW-bP7umRqDwF7A/s640/123456.jpeg" width="640" /></a></div> <br /> El consumo de este medicamento se incrementó en 60% el último año en Perú, pero su uso constante sin supervisión médica puede terminar afectando la visión.<br /> <br /> <div style="text-align: justify;"> <span style="font-size: small;"><strong>El consumo de medicamentos para tratar la disfunción eréctil, como el sildenafilo</strong> (conocido comercialmente como viagra), se incrementó en 60% el último año en Perú, pero su uso constante sin supervisión médica puede terminar afectando la visión, advirtieron hoy especialistas.</span></div> <div style="text-align: justify;"> <span style="font-size: small;">El presidente de la Sociedad Peruana de Urología, Alberto Pazos, dijo que <strong>el uso de este producto tiene una gran incidencia entre la población menor de 40 años, </strong>principalmente por una adicción psicológica causada por la inseguridad de mantener una relación sexual que complazca a su pareja.<br /><br /><strong>“Es una adicción psicológica, son personas (jóvenes) inseguras que no tienen la confianza para mantener una relación sexual porque creen que no van  rendir. </strong>Por eso tienen que depender del medicamento”, aseveró Pazos Franco en declaraciones a la Agencia Andina.<br /><br />Pazos cuestionó, asimismo, el hecho de que<strong> se venda este producto de manera indiscriminada,</strong> y sin receta médica, tanto a adultos mayores que tienen problemas de disfunción eréctil, como a jóvenes que lo adquieren solo para mejorar su rendimiento.<br /><br />Señaló, por ejemplo, que de acuerdo a recientes estudios, <strong>el 40% de pacientes mayores de 65 años han presentado problemas de disfunción sexual severa.</strong> Pazos asoció la disfunción eréctil a problemas de estrés, sobrepeso, uso de alcohol, drogas, así como a enfermedades como la diabetes.<br /><br />Por su parte, el químico farmacéutico de la Dirección General de Medicamentos (Digemid), Aldo Álvarez Risco, coincidió en que <strong>el uso constante del viagra puede causar problemas en la vista.</strong><br /><br />Cuestionó la función que cumplen las redes sociales para desinformar al público joven sobre el uso de medicamentos como el viagra, olvidando que <strong>existen médicos especialistas que les pueden instruir profesionalmente sobre sus dudas.</strong><br /><br /><strong>“Estos jóvenes enfrentan su primera experiencia sexual </strong>y quieren asegurarse de cumplir un excelente papel con su pareja, dejándose llevar por lo que dice la gente por las redes sociales”, concluyó.</span></div> <div style="text-align: justify;"> <br /></div> </div>

Consumo de viagra aumenta pero uso constante afecta la visión

Visualización optima 1600x900 pixel Comenta.esta.publicación El consumo de este medicamento se incrementó en 60% el último año en Per...

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Ratones ciegos recuperan la visión con solo una inyección

<div dir="ltr" style="text-align: left;" trbidi="on"> Visualización optima 1600x900 pixel Comenta.esta.publicación<br /> <br /> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmPJYCIuqgfY9TKYA1uhvTNpoBVTqhbY_cVbYvFcy2Y_F0vXftOsvxwnZLS1YwnAk43gzUJl67RBTlP1Y8LnCzETr6W1swGnx3s9zDKiGFnWQNEv5yfa1aihQ-1o6EnYZudORPHKJoHiw/s1600/123.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="263" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmPJYCIuqgfY9TKYA1uhvTNpoBVTqhbY_cVbYvFcy2Y_F0vXftOsvxwnZLS1YwnAk43gzUJl67RBTlP1Y8LnCzETr6W1swGnx3s9zDKiGFnWQNEv5yfa1aihQ-1o6EnYZudORPHKJoHiw/s320/123.jpg" width="320" /></a></div> <div class="separator" style="clear: both; text-align: center;"> <br /></div> <div class="separator" style="clear: both; text-align: center;"> <span style="background-color: white; color: #262626; font-family: Arial; font-size: 12px; font-style: italic; line-height: 15px; text-align: start;">Científicos británicos lograron restaurar la visión de ratones totalmente ciegos con una inyección de células fotorreceptoras en el ojo.</span></div> <div class="separator" style="clear: both; text-align: center;"> <span style="background-color: white; color: #262626; font-family: Arial; font-size: 12px; font-style: italic; line-height: 15px; text-align: start;"><br /></span></div> <div class="separator" style="clear: both; text-align: center;"> <span style="background-color: white; color: #262626; font-family: Arial; font-size: 12px; font-style: italic; line-height: 15px; text-align: start;"><br /></span></div> <br /> <div style="background-color: white; border: 0px; color: #555555; font-family: arial; font: inherit; line-height: 19px; margin-bottom: 15px; padding: 0px; text-align: justify; vertical-align: baseline;"> <strong style="border: 0px; font: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">Un equipo de científicos de la Universidad de Oxford logró restaurar la visión de ratones totalmente ciegos con una inyección de células fotorreceptoras,</strong> capaces de convertirse en los fundamentos de una retina una vez que están dentro del ojo.</div> <div style="background-color: white; border: 0px; color: #555555; font-family: arial; font: inherit; line-height: 19px; margin-bottom: 15px; padding: 0px; text-align: justify; vertical-align: baseline;"> Para el estudio, los investigadores utilizaron ratones con una carencia total de células fotorreceptoras en la retina. <strong style="border: 0px; font: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">Los ratones no podían ver la diferencia entre la luz y la oscuridad debido a una retinitis pigmentosa, enfermedad que provoca la pérdida gradual de las células fotorreceptores de la retina, encargadas de permitir la visión en condiciones de baja luminosidad</strong>, según informa la BBC.</div> <div style="background-color: white; border: 0px; color: #555555; font-family: arial; font: inherit; line-height: 19px; margin-bottom: 15px; padding: 0px; text-align: justify; vertical-align: baseline;"> "Logramos recrear toda la estructura, básicamente es la primera prueba de que puedes tomar a un ratón completamente ciego, inyectarle las células y reconstruir toda la capa fotorreceptora", dijo Robert MacLaren, quien dirigió el estudio.</div> <div style="background-color: white; border: 0px; color: #555555; font-family: arial; font: inherit; line-height: 19px; margin-bottom: 15px; padding: 0px; text-align: justify; vertical-align: baseline;"> El profesor MacLaren añade que la nueva investigación fue como "<strong style="border: 0px; font: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">restaurar toda la pantalla de una computadora y no sólo repara pixeles individuales</strong>".</div> <div style="background-color: white; border: 0px; color: #555555; font-family: arial; font: inherit; line-height: 19px; margin-bottom: 15px; padding: 0px; text-align: justify; vertical-align: baseline;"> Los expertos sostienen que este campo de investigación está avanzando rápidamente, pero todavía hay algunas dudas sobre la calidad de la visión que se ha logrado restablecer.</div> <div style="background-color: white; border: 0px; color: #555555; font-family: arial; font-size: 14px; font: inherit; line-height: 19px; margin-bottom: 15px; padding: 0px; vertical-align: baseline;"> <br /></div> </div>

Ratones ciegos recuperan la visión con solo una inyección

Visualización optima 1600x900 pixel Comenta.esta.publicación Científicos británicos lograron restaurar la visión de ratones totalmen...

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Unlocking Leber’s Hereditary Optic Neuropathy

<div dir="ltr" style="text-align: left;" trbidi="on"> Visualización optima 1600x900 pixel Comenta.esta.publicación<br /> <br /> <br /> <div class="ceintro" style="background-color: #fefefd; color: #333333; font-family: Arial, Helvetica, sans-serif; font-weight: bold; margin-bottom: 12px;"> Promising new research offers a glimmer of hope for an otherwise intractable disease.</div> <div class="ceauthor" style="background-color: #fefefd; color: #333333; font-family: Arial, Helvetica, sans-serif; font-style: italic; font-weight: bold; margin-bottom: 12px; margin-top: -8px;"> By Jerome Sherman, O.D., and Jinyoung Choe, B.A.</div> <div class="dates" style="background-color: #fefefd; color: #1b4475; font-family: Tahoma, Arial, Helvetica, sans-serif; font-weight: bold; height: 35px; margin: 0px; padding: 15px 0px 0px; text-transform: uppercase; width: 627px;"> <span style="color: #333333; font-family: Arial, Helvetica, sans-serif;">EXPIRATION DATE: NOVEMBER 1, 2015</span></div> <h2 style="background-color: #fefefd; color: #1b4475; font-family: Arial, Helvetica, sans-serif; margin: 15px 0px 2px; padding: 0px; text-transform: uppercase;"> <span style="font-size: small;">GOAL STATEMENT:</span></h2> <div style="background-color: #fefefd; color: #333333; font-family: Arial, Helvetica, sans-serif; margin-bottom: 12px;"> Leber’s hereditary optic neuropathy is an uncommon presentation in the optometrist’s office, but its quickly advancing effects will devastate a patient’s vision. While the condition was identified more than a century ago, there are no effective or approved treatments for it. However, at least one promising treatment is in the offing. This course reviews the characteristic ocular signs of Leber’s hereditary optic neuropathy and its typical progression, and also offers some new information on the potential treatment for this devastating condition.</div> <h2 style="background-color: #fefefd; color: #1b4475; font-family: Arial, Helvetica, sans-serif; margin: 15px 0px 2px; padding: 0px; text-transform: uppercase;"> <span style="font-size: small;">FACULTY/EDITORIAL BOARD:</span></h2> <div style="background-color: #fefefd; color: #333333; font-family: Arial, Helvetica, sans-serif; margin-bottom: 12px;"> <strong style="font-family: Tahoma, Arial, Helvetica, sans-serif;"></strong>Jerome Sherman, O.D., and Jinyoung Choe, B.A. He is the past president of the Optometric Retina Society and one of the founding members of the International Foundation of Optic Nerve Disease (IFOND).</div> <h2 style="background-color: #fefefd; color: #1b4475; font-family: Arial, Helvetica, sans-serif; margin: 15px 0px 2px; padding: 0px; text-transform: uppercase;"> <span style="font-size: small;">CREDIT STATEMENT:</span></h2> <div style="background-color: #fefefd; color: #333333; font-family: Arial, Helvetica, sans-serif; margin-bottom: 12px;"> This course is COPE approved for 2 hours of CE credit. COPE ID <strong style="font-family: Tahoma, Arial, Helvetica, sans-serif;">36331-NO</strong>. Check with your local state licensing board to see if this counts toward your CE requirements for relicensure.</div> <h2 style="background-color: #fefefd; color: #1b4475; font-family: Arial, Helvetica, sans-serif; margin: 15px 0px 2px; padding: 0px; text-transform: uppercase;"> <span style="font-size: small;">JOINT-SPONSORSHIP STATEMENT:</span></h2> <div style="background-color: #fefefd; color: #333333; font-family: Arial, Helvetica, sans-serif; margin-bottom: 12px;"> This continuing education course is joint-sponsored by the Pennsylvania College of Optometry.</div> <h2 style="background-color: #fefefd; color: #1b4475; font-family: Arial, Helvetica, sans-serif; margin: 15px 0px 2px; padding: 0px; text-transform: uppercase;"> <span style="font-size: small;">DISCLOSURE STATEMENT:</span></h2> <div style="background-color: #fefefd; color: #333333; font-family: Arial, Helvetica, sans-serif; margin-bottom: 12px;"> Dr. Sherman is on the Speakers Bureau for Carl Zeiss Meditec. Ms. Choe has no relationships to disclose. Dr. Sherman lectures and consults for Zeiss, Optovue, and Diopsys.</div> <hr style="background-color: #fefefd; color: dimgrey; font-family: Tahoma, Arial, Helvetica, sans-serif; height: 1pt;" /> <br style="background-color: #fefefd; color: #333333; font-family: Tahoma, Arial, Helvetica, sans-serif;" /><div style="background-color: #fefefd; color: #333333; font-family: Arial, Helvetica, sans-serif; margin-bottom: 12px;"> A century and a half ago, ophthalmologist Theodor Leber discovered an acute onset optic neuropathy that typically affects males in their 20s and invariably leads to bilateral optic atrophy and irreversible blindness.</div> <div style="background-color: #fefefd; color: #333333; font-family: Arial, Helvetica, sans-serif; margin-bottom: 12px;"> This disorder, now known as Leber's hereditary optic neuropathy (LHON), usually occurs in young men aged 15 to 30 years and less commonly in women of the same age.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">1</sup> It presents as an acute or subacute disease resulting in characteristic sudden, painless, sequential, bilateral loss of central vision, and ultimately in the formation of centrocecal scotomas.</div> <div style="background-color: #fefefd; color: #333333; font-family: Arial, Helvetica, sans-serif; margin-bottom: 12px;"> During the acute phase, the optic disc appears swollen and peripapillary retinal telangiectasias (corkscrew-appearing vessels) are typical. However, there is no disc leakage observed on fluorescein angiography (<i style="font-family: Tahoma, Arial, Helvetica, sans-serif;"><a href="http://www.revoptom.com/continuing_education/tabviewtest/lessonid/108694/#fig1" style="color: #003366; text-decoration: initial;">figure 1</a></i>).</div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgzoXNvJ-XZh5eEnFp6nYi2I9zmxrWI1wmDIYJmUoEdTBxRwm-l52cLm0_eQ4p47FOCjKaywU3E-qoWLthXwXkctCx5k8h4Ow7SNDBXziaAM4v2bcOOLDam93AhbnksIQsVW-iZ_GKm3jk/s1600/img1.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="385" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgzoXNvJ-XZh5eEnFp6nYi2I9zmxrWI1wmDIYJmUoEdTBxRwm-l52cLm0_eQ4p47FOCjKaywU3E-qoWLthXwXkctCx5k8h4Ow7SNDBXziaAM4v2bcOOLDam93AhbnksIQsVW-iZ_GKm3jk/s400/img1.jpg" width="400" /></a></div> <div class="separator" style="clear: both; text-align: center;"> <br /></div> <div class="separator" style="clear: both; text-align: center;"> </div> <div style="background-color: #fefefd; color: #333333; font-family: Arial, Helvetica, sans-serif; margin-bottom: 12px; text-align: left;"> In the vast majority of cases, vision loss is sequential—involvement of the second eye occurs weeks to months after the first. Visual deterioration is extreme, with acuity often plummeting to worse than 20/200 in each eye; vision reduced to bare light perception is common. Reports of LHON have usually described its course as a rapid visual deterioration (with the exception of one study that reported cases of slow and insidious visual loss).<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">5</sup></div> <div style="background-color: #fefefd; color: #333333; font-family: Arial, Helvetica, sans-serif; margin-bottom: 12px; text-align: left;"> In addition to LHON, Dr. Leber also described a congenital retinal disorder similar to retinitis pigmen-tosa but present at birth. This outer retinal disorder, termed Leber's congenital amaurosis (LCA), affects the photoreceptors and RPE but has no relationship to the optic nerve disorder LHON.</div> <div style="background-color: #fefefd; color: #333333; font-family: Arial, Helvetica, sans-serif; margin-bottom: 12px; text-align: left;"> Electroretinograpy (ERG), the best overall objective test of the retinal function of photoreceptors, is often extinguished or dramatically reduced in LCA. The outer retina (containing the photoreceptors) is normal in patients with LHON; hence, the ERG will be normal. Because LHON is an optic nerve disorder, the visual evoked potential (VEP) will be abnormal. Of interest, the VEP can demonstrate transmission delays even prior to vision loss in LHON.</div> <div style="background-color: #fefefd; color: #333333; font-family: Arial, Helvetica, sans-serif; margin-bottom: 12px; text-align: left;"> Another inherited optic neuropathy is Kjer's or auto-somal dominant optic atrophy. It can be transmitted by either parent and can be present in every generation. It is now believed that Kjer's is a mitochondrial optic neuropathy with involvement of the OPA1 gene.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">6</sup> These patients have a slowly progressive bilateral loss of visual acuity, color vision and central visual fields.</div> <h2 style="background-color: #fefefd; color: #1b4475; font-family: Arial, Helvetica, sans-serif; margin: 15px 0px 2px; padding: 0px; text-align: left; text-transform: uppercase;"> <span style="font-size: small;">CURRENT AND EMERGING TREATMENTS</span></h2> <div style="background-color: #fefefd; color: #333333; font-family: Arial, Helvetica, sans-serif; margin-bottom: 12px; text-align: left;"> Although the disease was identified in 1871, there are no effective or approved treatments for LHON or other related mitochondrial optic neuropathies.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">7</sup> Attempts to treat LHON have been largely unsuccessful, but early identification of LHON and avoidance of trigger mechanisms—such as smoking and alcohol—are now stressed to those with the genetic predisposition.</div> <div style="background-color: #fefefd; color: #333333; font-family: Arial, Helvetica, sans-serif; margin-bottom: 12px; text-align: left;"> Recently, a small open-label trial of an experimental therapeutic, EPI-743, which is being developed for life-threatening inherited respiratory chain diseases of the mitochondria, has demonstrated preliminary success in treating patients in the acute conversion phase of LHON.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">7</sup> EPI-743 arrested LHON progression and reversed vision loss in four out of five treated patients. Hopefully, the results of this pilot study will be validated through upcoming multicenter randomized controlled studies.</div> <br /> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjfvIyN2E4lcegEwdEIpnaMHfSpwPn_LMcwK16-nIzoaO62lnTw8veLc37IS5SxLSh8XLKvHPWxCornLvXFoJ1SLlc154LdVy8HqTBmmua9F7DJOAKX2HSsUDfouvr2TXX2GrbrSFj0zSw/s1600/chart1.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="288" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjfvIyN2E4lcegEwdEIpnaMHfSpwPn_LMcwK16-nIzoaO62lnTw8veLc37IS5SxLSh8XLKvHPWxCornLvXFoJ1SLlc154LdVy8HqTBmmua9F7DJOAKX2HSsUDfouvr2TXX2GrbrSFj0zSw/s640/chart1.gif" width="640" /></a></div> <div style="background-color: #fefefd; color: #333333; font-family: Arial, Helvetica, sans-serif; margin-bottom: 12px;"> <br /></div> <div style="background-color: #fefefd; color: #333333; font-family: Arial, Helvetica, sans-serif; margin-bottom: 12px;"> </div> <div style="margin-bottom: 12px;"> EPI-743 may be the first effective treatment for LHON—which has a well-known history of irreversible vision loss in patients (save for those cases with the 14484 mutation)—as well as other diseases with mitochondria-based pathophysiologic conditions. Edison Pharmaceuticals, the developer of the drug, announced in September 2012 that all subjects with Leigh syndrome—a severe neurological disorder in children with mitochondrial inheritance and with no approved treatments—treated with EPI-743 exhibited reversal of disease progression.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">8</sup> This is remarkable because Leigh syndrome is considered to be 100% progressive and 100% fatal.</div> <div style="margin-bottom: 12px;"> Gene therapy also is emerging as a possible, attractive option. A team at Bascom Palmer Eye Institute has reported the use of mitochondria-targeted adeno-associated virus (AAV)-based gene vector in experimental models of LHON.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">9</sup> These experiments suggest that this safe virus vector may act as a vehicle for the introduction of almost any mitochondrial gene into the adult organelle. The researchers have used this intervention to restore functional ND4 levels in LHON; hopefully, more promising research advances are on the horizon.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">9</sup></div> <h2 style="color: #1b4475; margin: 15px 0px 2px; padding: 0px; text-transform: uppercase;"> <span style="font-size: small;">CASE PRESENTATIONS</span></h2> <div style="margin-bottom: 12px;"> Because Leber's is a relatively uncommon presentation in the optometrist's office, and because diagnosis and treatment of LHON are experiencing revolutionary changes, let's take a closer look at this condition through three different clinical case studies.</div> <div style="margin-bottom: 12px;"> <b style="font-family: Tahoma, Arial, Helvetica, sans-serif;">Case 1: Left Eye Follows Right</b><br style="font-family: Tahoma, Arial, Helvetica, sans-serif;" />A 15-year-old Filipino male with an established family history of LHON mt 11778 was followed closely prior to and during the acute phase of LHON. Vision loss began in his right eye and was followed by similar changes in his left eye several months later. His progression to blindness was well documented with GDx scanning laser polarimetry (Carl Zeiss Meditec), Stratus OCT (Carl Zeiss Meditec), Humphrey automated perimetry (Carl Zeiss Meditec), visual evoked potentials and fundus photography.</div> <div style="margin-bottom: 12px;"> Both OCT and scanning laser polarimetry have shown that retinal nerve fiber layer (RNFL) thickening can precede vision loss, and that it occurs in a specific temporal sequence typically starting in the inferior temporal quadrant.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">10</sup> Temporal pallor several months after the acute onset correlates with the attenuation of the RNFL in the papillo-macular bundle, which was well documented in the patient's right eye. At the same time, thickening of the remaining RNFL was well revealed with the GDx.</div> <div style="margin-bottom: 12px;"> Several months after the RNFL thickened in the right eye—most likely as a result of both axoplasmic stasis and upregulation of mitochondria—it began thinning and resulted in optic atrophy.</div> <div style="margin-bottom: 12px;"> Although the patient had no symptoms from age nine to 12 and had 20/20 best-corrected visual acuity (BCVA) in each eye during this period, both discs were not normal and displayed the characteristic findings of LHON carriers who are at risk of converting. Symptoms and VA reduction began in the right eye in May 2007 (at age 15). By August of that year, VA was reduced below 20/400 and serial fundus photos revealed progression to marked temporal pallor.</div> <div style="margin-bottom: 12px;"> Advanced serial analysis, using the September 2004 GDx as a baseline, first revealed thickening and then thinning of the RNFL. Similar RNFL findings on OCT have been reported in other LHON patients.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">11</sup></div> <div style="margin-bottom: 12px;"> The patient's VA was 20/20 in September 2004, but the right disc revealed the characteristic peripapillary telangiectatic microangiopathy. In April 2007, slight worsening of the disc, and increased RNFL thickness on GDx, was documented at the time of conversion. By May 2007, we observed temporal disc pallor and the VA had dropped to 20/400 O.D. By August 2007, the entire disc appeared pale and BCVA was now reduced to counting fingers (<i style="font-family: Tahoma, Arial, Helvetica, sans-serif;"><a href="http://www.revoptom.com/continuing_education/tabviewtest/lessonid/108694/#fig2" style="color: #003366; text-decoration: initial;">figure 2</a></i>).</div> <div style="margin-bottom: 12px;"> <br /></div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjPNC6H-laE5Ao-fXbfZij0cHzjkBdQxi-HKRlKktk4pr_s8oqOJB9wQ0_g12WMvDmO7yZrVOYD7zB2jb-ftMDqV2BJP_C6gn3IP38DKmUEZ8AqFr9aHK0fJ4vEK4tQolyL3-w8WZH8tV8/s1600/img2.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjPNC6H-laE5Ao-fXbfZij0cHzjkBdQxi-HKRlKktk4pr_s8oqOJB9wQ0_g12WMvDmO7yZrVOYD7zB2jb-ftMDqV2BJP_C6gn3IP38DKmUEZ8AqFr9aHK0fJ4vEK4tQolyL3-w8WZH8tV8/s640/img2.jpg" width="520" /></a></div> <div class="separator" style="clear: both; text-align: center;"> <br /></div> <div class="separator" style="clear: both; text-align: center;"> </div> <div style="margin-bottom: 12px; text-align: left;"> The left disc and surrounding structures were nearly normal back in September 2004, except for slight disc hyperemia and subtle relative opacity of the RNFL. During the April 2007 visit, the disc and surrounding retina appeared relatively unchanged. BCVA in the left eye at this time was 20/20. Perhaps there was a slight increase in the relative opacity of the RNFL in the left eye in May 2007. BCVA was still 20/20 O.S.</div> <div style="margin-bottom: 12px; text-align: left;"> But by August 2007, progression of disc and changes in the surrounding retina were appreciable in the left eye. There was observable increase in disc hyperemia, increased thickness of the RNFL and the presence of some telangiectatic (corkscrew) vessels on and surrounding the optic disc in the left eye. BCVA had dropped to 20/40 O.S.</div> <div style="margin-bottom: 12px; text-align: left;"> Likewise, GDx Advanced Serial Analysis did not reveal any major change in the left eye until August 2007. During this visit, GDx revealed marked increased thickness inferior temporally in the left eye. Meanwhile, VA had dropped to 20/40 O.S., and the disc and surrounding RNFL had visibly worsened.</div> <div style="margin-bottom: 12px; text-align: left;"> Between September 2004 and April 2007, increased RNFL thickness was visualized in the right eye but not as marked in the left eye.</div> <div style="margin-bottom: 12px; text-align: left;"> Since the right eye converted first, we expected that increased disc pallor (representing optic atrophy) would be more evident in the right eye from May 2007 to August 2007 (<i style="font-family: Tahoma, Arial, Helvetica, sans-serif;"><a href="http://www.revoptom.com/continuing_education/tabviewtest/lessonid/108694/#fig3" style="color: #003366; text-decoration: initial;">figure 3</a></i>).</div> <div style="margin-bottom: 12px; text-align: left;"> <br /></div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgzh9BVFKu7tHjGwMK5PM8rU78DzjIWCyYxNTvrJuPW7IOQ5hBv3k2eR3E9SkvSjoHyR4t8hmaI_cJpoELoFRQshHb0MJMpAILUZyHhQfwmyDa6OEDbyo4vHTypDCQPCUGOPE8dSMSre8g/s1600/img3.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgzh9BVFKu7tHjGwMK5PM8rU78DzjIWCyYxNTvrJuPW7IOQ5hBv3k2eR3E9SkvSjoHyR4t8hmaI_cJpoELoFRQshHb0MJMpAILUZyHhQfwmyDa6OEDbyo4vHTypDCQPCUGOPE8dSMSre8g/s640/img3.jpg" width="628" /></a></div> <div style="margin-bottom: 12px; text-align: left;"> <br /></div> <br /> <div style="margin-bottom: 12px;"> On the same day that the RNFL was attenuated in the right eye (as revealed on the August 2007 visit), the RNFL in the left eye was increased in thickness. The RNFL was markedly reduced inferiorly in the right eye but increased in the left eye (<i style="font-family: Tahoma, Arial, Helvetica, sans-serif;">figures <a href="http://www.revoptom.com/continuing_education/tabviewtest/lessonid/108694/#fig4" style="color: #003366; text-decoration: initial;">4</a> and <a href="http://www.revoptom.com/continuing_education/tabviewtest/lessonid/108694/#fig5" style="color: #003366; text-decoration: initial;">5</a></i>). Within the next year, both RNFLs were profoundly and equally reduced in thickness and both discs were equally pale</div> <div style="margin-bottom: 12px;"> <br /></div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYNrlYBCNZ4lAFP9nC2-pDVzl5B73Ck9pI-c3RoKvR5KSyK7pvKYBdK4MV3zLuRdQu69Ra53_XwORvVhwlOXvdybb_MhSz-oxr-3CJQQltAcLM43pv97uyXCdA4Htrt6YgWSYj2jZk7uo/s1600/img4.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="532" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYNrlYBCNZ4lAFP9nC2-pDVzl5B73Ck9pI-c3RoKvR5KSyK7pvKYBdK4MV3zLuRdQu69Ra53_XwORvVhwlOXvdybb_MhSz-oxr-3CJQQltAcLM43pv97uyXCdA4Htrt6YgWSYj2jZk7uo/s640/img4.jpg" width="640" /></a></div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhCeWKmsTf6fqCiXX9RfcvM9IwfUFeTWNUHrMLr2gS3fjlksNFck-y6norXlGfbtpW3ZlvpAZrowGzEcGw7KN8CF8JwD2repTeKghEj5IuvNaYqxl-kQIdCJvKhYa7MKOFv4RmFbgtrEzQ/s1600/img5.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="272" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhCeWKmsTf6fqCiXX9RfcvM9IwfUFeTWNUHrMLr2gS3fjlksNFck-y6norXlGfbtpW3ZlvpAZrowGzEcGw7KN8CF8JwD2repTeKghEj5IuvNaYqxl-kQIdCJvKhYa7MKOFv4RmFbgtrEzQ/s640/img5.jpg" width="640" /></a></div> <div style="margin-bottom: 12px;"> </div> <div style="margin-bottom: 12px;"> By April 2007, there was an obvious central sco-toma in the right eye. Most of the visual field was lost during the next five months. By the August 2007 visit, a central-cecal scotoma was documented in the left eye. The field loss was far more dramatic in the right eye during this period.</div> <div style="margin-bottom: 12px;"> About a year later, the field was profoundly reduced and equal in each eye. Currently, the patient has visual acuity of counting fingers O.U.</div> <div style="margin-bottom: 12px;"> <b style="font-family: Tahoma, Arial, Helvetica, sans-serif;">Case 2: A Trial Treatment</b><br style="font-family: Tahoma, Arial, Helvetica, sans-serif;" />The mother of a 27-year-old white male called and reported that her son began experiencing blurred vision in his right eye several weeks earlier. The patient has a family history of optic atrophy, and genetic testing nearly two decades earlier revealed a mitochondrial mutation at 11778, confirming Leber's hereditary optic neuropathy.</div> <div style="margin-bottom: 12px;"> We suspected acute or sub-acute conversion from a carrier state to affected state, so we evaluated the patient that evening. With a low myopic correction, BCVA was a slow 20/25- O.D. and 20/20 O.S. Pupils were normal with no relative afferent pupillary defect (RAPD). (Of interest, the pupil is often spared in LHON due to the preservation of the melanopsin retinal ganglion cells.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">9</sup>) OCT fundus images revealed the characteristic signs of disc hyperemia and telangi-ectatic vessels (<i style="font-family: Tahoma, Arial, Helvetica, sans-serif;"><a href="http://www.revoptom.com/continuing_education/tabviewtest/lessonid/108694/#fig6" style="color: #003366; text-decoration: initial;">figure 6</a></i>).</div> <div style="margin-bottom: 12px;"> <br /></div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgJ6jghNC_ioOF2qPa85XcTX6OxwWjLVr_hVLN9Dk4fDe35buxAxDLIJjb7q4I3-wg4BX93cXZatjzZJwyRGo5mS4Is3Yf1OikYsLKKUuzf3M-bH_p8AXUECaW2rciz41JCxUOYq9YPlAE/s1600/img6.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="410" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgJ6jghNC_ioOF2qPa85XcTX6OxwWjLVr_hVLN9Dk4fDe35buxAxDLIJjb7q4I3-wg4BX93cXZatjzZJwyRGo5mS4Is3Yf1OikYsLKKUuzf3M-bH_p8AXUECaW2rciz41JCxUOYq9YPlAE/s640/img6.jpg" width="640" /></a></div> <div style="margin-bottom: 12px;"> <br /></div> <div style="margin-bottom: 12px;"> </div> <div style="margin-bottom: 12px;"> A Macular Integrity Assessment (MAIA, Ellex) central field was obtained in each eye. This device uses a near infrared scanning laser ophthalmoscope to provide high-resolution retinal images; it is designed to evaluate the patient's macula threshold, fixation stability and change over time. The MAIA monitors eye position 25 times each second and then adjusts the placement of each stimulus onto the intended location regardless of fixation errors.</div> <div style="margin-bottom: 12px;"> For the patient's MAIA sensitivity map and threshold histogram O.D., sensitivity values depicted in green are normal, those in yellow are borderline and those in red are reduced significantly (<i style="font-family: Tahoma, Arial, Helvetica, sans-serif;"><a href="http://www.revoptom.com/continuing_education/tabviewtest/lessonid/108694/#fig7" style="color: #003366; text-decoration: initial;">figure 7</a></i>). The patient's fixation was determined to be quite stable in the right eye. The pattern of sensitivity reduction corresponded to the papillo-macular bundle.</div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhE0L3cmbg7Ql-4A_buoeLKKJeN3zZQEHb9tnGX1Z9CPCDdFMkhRSUfIBcLSPmKsB1dUw7RqZr636di_O3WuWRVJLBe2bJ5qNnmyoqqJOdJjIUX76rHZ87CXiOEnfcIm9D9xgRiGpzob8E/s1600/img7.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="510" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhE0L3cmbg7Ql-4A_buoeLKKJeN3zZQEHb9tnGX1Z9CPCDdFMkhRSUfIBcLSPmKsB1dUw7RqZr636di_O3WuWRVJLBe2bJ5qNnmyoqqJOdJjIUX76rHZ87CXiOEnfcIm9D9xgRiGpzob8E/s640/img7.jpg" width="640" /></a></div> <div style="margin-bottom: 12px;"> </div> <div style="margin-bottom: 12px;"> In the traditional 30-2 visual field, the defect is located primarily in the central superior field. In the MAIA field, the defect is projected back onto the corresponding retina.</div> <div style="margin-bottom: 12px;"> In the right eye as in the left eye, fixation was stable, and four points had a mildly reduced sensitivity to 23dB.</div> <div style="margin-bottom: 12px;"> Virtually all patients with the LHON mt 11778 progress to profound vision loss within weeks to months following initial vision loss. The second eye becomes affected within just several months, and final VA is typically the same in each eye. Visual fields are far better than VA to assess any change over time. When VA drops, many patients with various optic nerve and macula disorders change fixation to a more sensitive retinal location. With standard fields, the visual field loss "moves" when fixation is altered. Unlike standard fields, MAIA monitors eye position, corrects for changes in fixation (25 times per second) and tests the same points on any future MAIA visual field.</div> <div style="margin-bottom: 12px;"> Although the BCVA was 20/25-O.D. and 20/20 O.S., the MAIA visual field (<i style="font-family: Tahoma, Arial, Helvetica, sans-serif;"><a href="http://www.revoptom.com/continuing_education/tabviewtest/lessonid/108694/#fig7" style="color: #003366; text-decoration: initial;">figure 7</a></i>) demonstrates a dramatic difference in the central visual field sensitivity between the two eyes.</div> <div style="margin-bottom: 12px;"> The ganglion cell complex, or GCC (which is composed of the RNFL, the ganglion cell layer and the inner plexiform layer), appeared normal and equal in each eye. Very minor differences between all GCC measurements suggest that the central field loss at this point is reversible because the ganglion cells and corresponding axons and dendrites are still intact.</div> <div style="margin-bottom: 12px;"> All the findings supported the diagnosis of acute-onset LHON. Accordingly, we recommended that the patient take the first plane the next morning to Los Angeles for possible treatment with Edison Pharmaceutical's new drug EPI-743. All the data, including the previous genetic confirmation of LHON mt 11778, was shared with the group at Doheney Eye Institute, USC Keck School of Medicine. Within a week, treatment was initiated once the FDA approval was obtained.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">7</sup> As mentioned previously, favorable results in four other patients with LHON will perhaps lead to an FDA clinical trial in the near future.</div> <div style="margin-bottom: 12px;"> The MAIA was repeated 24 days after the initial visit (two weeks after the initiation of treatment). The sensitivity of many points decreased significantly in the right eye. But in the left eye, sensitivity of various points tested improved slightly, although none reached statistical significance. Take note that the drug has only been tested on a small number of people with LHON, so we have only limited information about how long the drug takes to work. The consensus among researchers involved with EPI-743 is that the drug does not demonstrate a significant effect until six to eight months after initiation of treatment.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">12</sup></div> <div style="margin-bottom: 12px;"> Because the patient in this case was treated very early in the course of the disease, improvement in visual field sensitivity is still possible because the ganglion cell complex has yet revealed no loss of cells.</div> <div style="margin-bottom: 12px;"> <b style="font-family: Tahoma, Arial, Helvetica, sans-serif;">Case 3: Atypical, Early LHON </b><br style="font-family: Tahoma, Arial, Helvetica, sans-serif;" />A 7-year-old hyperactive white male was evaluated because of possible reduction of VA and possible disc pallor. He was previously diagnosed with attention deficit hyperactivity disorder (ADHD), which likely explained the difficulty in examining the patient. A female resident who spent considerable time with him was able to correct his VA to 20/20 O.D. and O.S. Although ophthalmoscopy revealed temporal pallor, it was unclear whether this was physiologic or pathologic (<i style="font-family: Tahoma, Arial, Helvetica, sans-serif;"><a href="http://www.revoptom.com/continuing_education/tabviewtest/lessonid/108694/#fig8" style="color: #003366; text-decoration: initial;">figure 8</a></i>). Digital tonometry revealed soft globes.</div> <div class="separator" style="clear: both; font-size: 13px; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglAmSPdunom707esLs_5R6c3Hdv_KNQBgXDm1yoADbaQZgyU9eW9qdpCR-sS8cjATEaskfIcszDd-L_1MdDiCoWKL3BzTJsUd1YDIOgXTIZWqOZxclV0qwnTdGkFeEe8hWlU9P1e8cgkM/s1600/img8.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="384" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglAmSPdunom707esLs_5R6c3Hdv_KNQBgXDm1yoADbaQZgyU9eW9qdpCR-sS8cjATEaskfIcszDd-L_1MdDiCoWKL3BzTJsUd1YDIOgXTIZWqOZxclV0qwnTdGkFeEe8hWlU9P1e8cgkM/s640/img8.jpg" width="640" /></a></div> <div style="font-size: 13px; margin-bottom: 12px;"> <br /></div> <div class="separator" style="clear: both; font-size: 13px; text-align: center;"> </div> <div style="margin-bottom: 12px;"> Optovue iWellness Exam revealed normal sections through the retina (not shown) in the posterior pole but a profound reduction of the thickness of the GCC in both eyes (<i style="font-family: Tahoma, Arial, Helvetica, sans-serif;"><a href="http://www.revoptom.com/continuing_education/tabviewtest/lessonid/108694/#fig9" style="color: #003366; text-decoration: initial;">figure 9</a></i>). Note the comparison to a normal patient below.</div> <div class="separator" style="clear: both; font-size: 13px; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjH7SIlJeMFeCeieiMofPOoVd8ehcAgORE8hFsSUrtaW6o8NtiRQTYG57RFhKQUa_sEJ6J9J6JVdM-8mXG9I7-RQ38DPoq_KWtZ8niWTk_mLUXXf3CRfXSjuwk0kmOv-lnfibfZ51e2ZX8/s1600/img9.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="550" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjH7SIlJeMFeCeieiMofPOoVd8ehcAgORE8hFsSUrtaW6o8NtiRQTYG57RFhKQUa_sEJ6J9J6JVdM-8mXG9I7-RQ38DPoq_KWtZ8niWTk_mLUXXf3CRfXSjuwk0kmOv-lnfibfZ51e2ZX8/s640/img9.jpg" width="640" /></a></div> <div style="font-size: 13px; margin-bottom: 12px;"> <br /></div> <div style="margin-bottom: 12px;"> Diopsys VEPs were obtained under NOVA-DN conditions (<i style="font-family: Tahoma, Arial, Helvetica, sans-serif;"><a href="http://www.revoptom.com/continuing_education/tabviewtest/lessonid/108694/#fig10" style="color: #003366; text-decoration: initial;">figure 10</a></i>). The amplitudes of the VEP under both high contrast and low contrast conditions were normal in both eyes. However, the latency was abnormal under all conditions tested. The amplitudes are consistent with the normal VA, but the large latency increases clearly indicate a bilateral optic neuropathy. Automated visual fields were attempted but were not possible on either of two visits due to the boy's ADHD.</div> <div style="font-size: 13px; margin-bottom: 12px;"> <br /></div> <div class="separator" style="clear: both; font-size: 13px; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjlM-JhMZTUmlkm7Bfo7zpstdTCca_o2xEazb3QBl7Ynw7uGfVnu4DOFqVnilJel5tlEYLOStOyHKSFCT4_AOiWFUy3ZQszo88O22j6mlg_Sg7pn6S8tmS0tzlcICPuZzmbT_VNlarJbko/s1600/img10.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjlM-JhMZTUmlkm7Bfo7zpstdTCca_o2xEazb3QBl7Ynw7uGfVnu4DOFqVnilJel5tlEYLOStOyHKSFCT4_AOiWFUy3ZQszo88O22j6mlg_Sg7pn6S8tmS0tzlcICPuZzmbT_VNlarJbko/s640/img10.jpg" width="566" /></a></div> <div style="margin-bottom: 12px;"> </div> <div style="font-size: 13px; margin-bottom: 12px;"> <br /></div> <div style="margin-bottom: 12px;"> The dramatic reduction in ganglion cell complex and the VEP delays in both eyes confirm an optic nerve disorder. So what could the etiology of this optic neuropa-thy possibly be?</div> <div style="margin-bottom: 12px;"> Because our 7-year-old appears to have pale discs without cupping and soft globes, glaucoma is effectively ruled out. But other non-glaucomatous optic neuropa-thies need to be considered, which can be done using the VITAMINES mnemonic (<i style="font-family: Tahoma, Arial, Helvetica, sans-serif;"><a href="http://www.revoptom.com/continuing_education/tabviewtest/lessonid/108694/#vitamins" style="color: #003366; text-decoration: initial;">below</a></i>).</div> <div style="font-size: 13px; margin-bottom: 12px;"> <br /></div> <div class="separator" style="clear: both; font-size: 13px; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJ_u2wtIo-bWtRbSywg3NThDB-QyANOr47-qHrUxkWUOyZCPRWV8sGPgKo9UbteH3eyj3HEk6gNNCnhiDNxXe3U6Aw87nBwV2g516H10N0FrKjtg6spFfT9Z_ApwmVV-R8EoQG4yjdENU/s1600/take-your-vitamins.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJ_u2wtIo-bWtRbSywg3NThDB-QyANOr47-qHrUxkWUOyZCPRWV8sGPgKo9UbteH3eyj3HEk6gNNCnhiDNxXe3U6Aw87nBwV2g516H10N0FrKjtg6spFfT9Z_ApwmVV-R8EoQG4yjdENU/s640/take-your-vitamins.jpg" width="504" /></a></div> <div style="margin-bottom: 12px;"> </div> <div style="margin-bottom: 12px;"> MRIs were obtained, which were within normal limits. However, a detailed family history revealed an optic neuropathy, specifically LHON with a point mutation at mt 4360. Hence, our VITAMINES mnemonic was helpful in guiding the differential diagnosis and workup.</div> <div style="margin-bottom: 12px;"> Although LHON is considered to be an acute-onset disorder at an average age of 25, it can occur in the first decade of life with a subacute presentation.<sup style="font-family: Tahoma, Arial, Helvetica, sans-serif;">10</sup> The entire family is in the process of being evaluated. A confirmed diagnosis of LHON is more important than ever because treatment may soon be available.</div> <div style="margin-bottom: 12px;"> This was an unusual case in that the patient had normal VA but showed dramatic reduction in the ganglion cell complex and delayed VEPs. Currently, this patient (and his older brother and sister) are being followed very carefully for any change.</div> <div style="margin-bottom: 12px;"> In summary, acute-onset LHON typically begins in one eye followed within several months by the other eye. Disc hyperemia and peripapillary telangiectasia correspond to an increased RNFL thickness, as revealed with fundus photography, GDx and OCT. As the first eye begins to experience RNFL loss and disc pallor, the second eye may begin the same sequence. Within a year or so after the initial acute presentation in one eye, both eyes appear very similar.</div> <div style="margin-bottom: 12px;"> One goal in the treatment of LHON is to prevent the second eye from converting. For the first time in the 150 years since Dr. Leber reported this progressive optic neuropathy, an effective treatment to meet this goal may be on the horizon. It may be instituted at the time of initial vision loss in the first eye. If successful, perhaps the second eye can be protected from converting and a large difference between the two eyes will still exist a year or so following the initiation of treatment.</div> <div style="margin-bottom: 12px;"> <i style="font-family: Tahoma, Arial, Helvetica, sans-serif;">Dr. Sherman is a distinguished teaching professor at State University of New York College of Optometry and the Schnurmacher Institute of Vision Research. He also practices at The Eye Institute and Laser Center, New York City, and is the current president of the Optometric Retina Society.</i></div> <div style="margin-bottom: 12px;"> <i style="font-family: Tahoma, Arial, Helvetica, sans-serif;">Ms. Choe graduated from University of Califor-nia-Berkeley with a B.A. in Integrative Biology. 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Unlocking Leber’s Hereditary Optic Neuropathy

Visualización optima 1600x900 pixel Comenta.esta.publicación Promising new research offers a glimmer of hope for an otherwise intractab...

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