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24 January 2012

Researchers develop gene therapy that could correct a common form of blindness

A new gene therapy method developed by University of Florida researchers has the potential to treat a common form of blindness that strikes both youngsters and adults. The technique works by replacing a malfunctioning gene in the eye with a normal working copy that supplies a protein necessary for light-sensitive cells in the eye to function. The findings are published Jan. 23 in the Proceedings of the National Academy of Sciences online.
Several complex and costly steps remain before the gene therapy technique can be used in humans, but once at that stage, it has great potential to change lives.
"Imagine that you can't see or can just barely see, and that could be changed to function at some levels so that you could read, navigate, maybe even drive -- it would change your life considerably," said study co-author William W. Hauswirth, Ph.D., the Rybaczki-Bullard professor of ophthalmology in the UF College of Medicine and a professor and eminent scholar in department of molecular genetics and microbiology and the UF Genetics Institute. "Providing the gene that's missing is one of the ultimate ways of treating disease and restoring significant visual function."
The researchers tackled a condition called X-linked retinitis pigmentosa, a genetic defect that is passed from mothers to sons. Girls carry the trait, but do not have the kind of vision loss seen among boys. About 100,000 people in the U.S. have a form of retinitis pigmentosa, which is characterized by initial loss of peripheral vision and night vision, which eventually progresses to tunnel vision, then blindness. In some cases, loss of sight coincides with the appearance of dark-colored areas on the usually orange-colored retina.
The UF researchers previously had success pioneering the use of gene therapy in clinical trials to reverse a form of blindness known as Leber's congenital amaurosis. About 5 percent of people who have retinitis pigmentosa have this form, which affects the eye's inner lining.
"That was a great advance, which showed that gene therapy is safe and lasts for years in humans, but this new study has the potential for a bigger impact, because it is treating a form of the disease that affects many more people," said John G. Flannery, Ph.D., a professor of neurobiology at the University of California, Berkeley who is an expert in the design of viruses for delivering replacement genes. Flannery was not involved in the current study.
The X-linked form of retinitis pigmentosa addressed in the new study is the most common, and is caused by degeneration of light-sensitive cells in the eyes known as photoreceptor cells. It starts early in life, so though affected children are often born seeing, they gradually lose their vision.
"These children often go blind in the second decade of life, which is a very crucial period," said co-author Alfred S. Lewin, Ph.D., a professor in the UF College of Medicine department of molecular genetics and microbiology and a member of the UF Genetics Institute. "This is a compelling reason to try to develop a therapy, because this disease hinders people's ability to fully experience their world."
Both Lewin and Hauswirth are members of UF's Powell Gene Therapy Center.
The UF researchers and colleagues at the University of Pennsylvania performed the technically challenging task of cloning a working copy of the affected gene into a virus that served as a delivery vehicle to transport it to the appropriate part of the eye. They also cloned a genetic "switch" that would turn on the gene once it was in place, so it could start producing a protein needed for the damaged eye cells to function.
After laboratory tests proved successful, the researchers expanded their NIH-funded studies and were able to cure animals in which X-linked retinitis pigmentosa occurs naturally. The injected genes made their way only to the spot where they were needed, and not to any other places in the body. The study gave a good approximation of how the gene therapy might work in humans.
"The results are encouraging and the rescue of the damaged photoreceptor cells is quite convincing," said Flannery, who is on the scientific advisory board of the Foundation Fighting Blindness, which provided some funding for the study. "Since this type of study is often the step before applying a treatment to human patients, showing that it works is critical."
The researchers plan to repeat their studies on a larger scale over a longer term, and make a version of the virus that proves to be safe in humans. Once that is achieved, a pharmaceutical grade of the virus would have to be produced and tested before moving into clinical trials in humans. The researchers will be able to use much of the technology they have already developed and used successfully to restore vision.

**Source: University of Florida Health Science Center

¿Células madre para la ceguera por degeneración macular?

¿Pueden las células madre contribuir al tratamiento de la ceguera por degeneración macular? Los resultados "muy preliminares" obtenidos por un grupo de científicos liderados por Steven D. Schwartz, oftalmólogo del Instituto Jules Stein Eye (EEUU), así lo sugieren.
En el estudio se trataron a dos mujeres. Ambas sufrían degeneración macular por edad. A sus 80 años, esta pérdida de visión progresiva complicaba la vida de Sue Freeman y otra mujer que no ha hecho pública su identidad. "A causa de la enfermedad había perdido casi toda la visión y ya no podía reconocer las caras, leer, cocinar o salir a la calle sin miedo", explica Freeman a 'National Public Radio'.
Los investigadores utilizaron células madre de embriones para crear las células del epitelio pigmentario (capa de células pigmentadas que aparece en el exterior de la retina) en el laboratorio. Según explica en 'The Lancet', donde se publica el trabajo, Schwartz y sus compañeros inyectaron alrededor de 50.000 de estas células en el ojo derecho de la señora Freeman.

Los investigadores piden cautela: "Es demasiado pronto para sacar conclusiones", repite el doctor Schwartz. "En principio el estudio estaba diseñado para determinar cómo se comportaban las células inyectadas, pero no para saber si en realidad podrían ayudar a los pacientes", explica. "Para este estudio los pacientes recibieron dosis muy bajas y como su visión estaba tan dañada no pensábamos que las células madre pudiesen ayudarles", comenta.
"Estoy muy emocionado con todo esto porque el impacto en este grupo de pacientes es enorme", explica este oftalmólogo, que reconoce que el número de pacientes es ínfimo para saber si hablamos de un futuro tratamiento.
"Todavía es demasiado pronto para saber nada con seguridad. Los pacientes podrían seguir mejorando, pero también su visión podría volver a deteriorarse de nuevo", analiza. "Necesitaremos muchos más pacientes y más tiempo para saber si estamos ante un tratamiento seguro y que es responsable de la mejora".

Un estudio afirmar que es clave detectar la dislexia antes de desarrollarla

La dislexia podría detectarse incluso antes de que los niños aprendan a leer. Según un equipo de investigadores de EEUU, su actividad cerebral muestra algunas diferencias fáciles de captar por resonancia magnética y así lo confirman en un artículo publicado en 'Proceedings of the National Academy of Sciences'.
Ya se sospechaba que este tipo de problemas de aprendizaje de la lectura y la escritura "seguramente tienen alteraciones neurobiológicas y funcionales a nivel cerebral (temporal o frontal)", aclara Gustavo Lorenzo, neurólogo infantil del Hospital Ramón y Cajal de Madrid. Los resultados de esta investigación, realizada en el Hospital Infantil de Boston, suponen un nuevo apoyo a esta teoría.
Después de hacer resonancias magnéticas a 36 niños (con una edad media de cinco años) mientras decidían si dos palabras comenzaban con el mismo sonido, los autores de este trabajo observaron que los que tenían historial familiar de dislexia mostraban menos actividad metabólica en algunas zonas cerebrales.
Concretamente, en las uniones entre los lóbulos occipital y temporal y en los lóbulos temporal y parietal. Lo que indica, asegura la principal autora de la investigación, Nora Raschle, es que "la capacidad del cerebro para procesar los sonidos del lenguaje es deficiente, incluso antes de que estos niños aprendan a leer". Por el contrario, quienes presentaban una alta activación en esta región cerebral, tenían mejores habilidades lectoras, como la rima, el conocimiento de las letras y sus sonidos.
Para Raschle, este hallazgo una buena noticia: "La identificación precoz de los niños que probablemente desarrollen dislexia puede ayudar a reducir las consecuencias negativas a las que se enfrentan desde el punto de vista social y psicológico". A lo largo del artículo recuerda que muchos estudios han demostrado que los afectados suelen tener malas experiencias en la escuela, son calificados como perezosos o desmotivados, y su frustración a veces conlleva comportamientos impulsivos y antisociales, además de un mayor riesgo de abandonar el colegio.
Una aplicación muy positiva que requiere cierta prudencia. "Es muy difícil determinar con exactitud qué áreas están afectadas. El cerebro es muy complejo", matiza el doctor Lorenzo. Además, agrega, "hay que tener en cuenta que quizás esa reducción de actividad metabólica en determinadas zonas cerebrales no se deba a una posible dislexia sino a que el niño aún no ha desarrollado dicha área (y la puede desarrollar después)". A esas edades, en el transcurso de un año, las diferencias madurativas son importantes y no significan un problema. Para entenderlo mejor, "puedes hablar con dos o tres años, pero se considera normal no hacerlo hasta los cuatro".
En definitiva, "hasta que no llega el momento de poner en práctica la habilidad de la lectura y la comprensión (a los seis años, aproximadamente), no se puede hacer nada. Sólo entonces, se recomienda un apoyo continuo en la etapa escolar de rehabilitación y trabajo específicos para ayudar al afectado", argumenta el neurólogo español. Después, cuando sea adulto, "será consciente de esta dificultad y sabrá que tiene que dedicar más tiempo, atención y esfuerzo, como cuando lees en inglés y no eres bilingüe. Sabes que tienes que ir más despacio".
Se calcula que entre el 5% y el 17% de los pequeños tiene dislexia, es decir, problemas con la lectura, la mala ortografía, dificultad para reconocer palabras con fluidez y para comprender lo que leen. Los que vemos en la consulta de neurología, afirma el doctor Lorenzo, "además de dislexia tienen otros problemas, sobre todo de atención e hiperactividad y por eso les mantenemos en tratamiento farmacológico". Pero la dislexia aislada sólo requiere trabajo, rehabilitación y constancia, "no para curar sino para evolucionar".

**Publicado en "EL MUNDO"

Researchers quantify muscle soreness



Quantifying how sore a person is after a long workout is a challenge for doctors and researchers, but scientists from Loma Linda and Asuza Pacific Universities think they may have figured it out. Their research article describing a new technique to measure muscle soreness will be published in the Journal of Visualized Experiments (JoVE). Delayed onset muscle soreness (DOMS) or exercise-induced muscle damage (EIMD) is one of the most common sports injuries, but without a reliable method of quantifying muscle soreness, assessing treatments is difficult.
Traditionally, muscle soreness has been measured using the visual analogue scale (VAS). Participants mark their level of agreement to a statement along a continuous line. Rather than measuring soreness subjectively, the researchers used thermal imaging to detect subtle changes in the temperature of the skin above exercised muscles.
"The main advantage of this technique," said paper author Dr. Jerrold Petrofsky, "is that unlike visual scales, which are kind of a subjective measure of whether someone is sore or not, this technique gives you quantifiable, absolute data."
"There is no gold standard for measuring DOMS and other techniques, such as needle biopsies, are invasive and painful for patients," said JoVE Editor, Leiam Colbert. "The technique presented here allows for earlier diagnosis and quicker treatment of soreness."
The very visual technique was published recently in JoVE, the world's only peer reviewed, PubMed indexed science video journal.

*Picture:(c) Journal of Visualized Experiments
**Source: The Journal of Visualized Experiments

Una campaña viral para alertar de las dificultades de los discapacitados para obtener un empleo logra 100.000 visitas

Lifelong brain-stimulating habits linked to lower Alzheimer's protein levels



A new study led by researchers at the University of California, Berkeley, provides even more reason for people to read a book or do a puzzle, and to make such activities a lifetime habit. Brain scans revealed that people with no symptoms of Alzheimer's who engaged in cognitively stimulating activities throughout their lives had fewer deposits of beta-amyloid, a destructive protein that is the hallmark of the disease.
While previous research has suggested that engaging in mentally stimulating activities -- such as reading, writing and playing games -- may help stave off Alzheimer's later in life, this new study identifies the biological target at play. This discovery could guide future research into effective prevention strategies.
"These findings point to a new way of thinking about how cognitive engagement throughout life affects the brain," said study principal investigator Dr. William Jagust, a professor with joint appointments at UC Berkeley's Helen Wills Neuroscience Institute, the School of Public Health and Lawrence Berkeley National Laboratory. "Rather than simply providing resistance to Alzheimer's, brain-stimulating activities may affect a primary pathological process in the disease. This suggests that cognitive therapies could have significant disease-modifying treatment benefits if applied early enough, before symptoms appear."
An estimated 5.4 million Americans live with Alzheimer's disease, but the numbers are growing as baby boomers age. Between 2000 and 2008, deaths from Alzheimer's increased 66 percent, making it the sixth-leading killer in the country. There is currently no cure, but a draft of the first-ever National Alzheimer's Plan, released this week, revealed that the U.S. government is aiming for effective Alzheimer's treatments by 2025.
The new study, published Jan. 23 in the Archives of Neurology, puts the spotlight on amyloid -- protein fibers folded into tangled plaques that accumulate in the brain. Beta-amyloid is considered the top suspect in the pathology of Alzheimer's disease, so finding a way to reduce its development has become a major new direction of research.
The researchers note that the buildup of amyloid can also be influenced by genes and aging -- one-third of people age 60 and over have some amyloid deposits in their brain -- but how much reading and writing one does is under each individual's control.
"This is the first time cognitive activity level has been related to amyloid buildup in the brain," said study lead author Susan Landau, research scientist at the Helen Wills Neuroscience Institute and the Berkeley Lab. "Amyloid probably starts accumulating many years before symptoms appear. So it's possible that by the time you have symptoms of Alzheimer's, like memory problems, there is little that can be done to stop disease progression. The time for intervention may be much sooner, which is why we're trying to identify whether lifestyle factors might be related to the earliest possible changes."
The researchers asked 65 healthy, cognitively normal adults aged 60 and over (average age was 76) to rate how frequently they participated in such mentally engaging activities as going to the library, reading books or newspapers, and writing letters or email. The questions focused on various points in life from age 6 to the present.
The participants took part in extensive neuropsychological testing to assess memory and other cognitive functions, and received positron emission tomography (PET) scans at the Berkeley Lab using a new tracer called Pittsburgh Compound B that was developed to visualize amyloid. The results of the brain scans of healthy older individuals with various levels of lifetime cognitive activity were compared with those of 10 patients diagnosed with Alzheimer's disease and 11 healthy people in their 20s.
The researchers found a significant association between higher levels of cognitive activity over a lifetime and lower levels of beta-amyloid in the PET scans. They analyzed the impact of other factors such as memory function, physical activity, self-rated memory ability, level of education and gender, and found that lifelong cognitive engagement was independently linked to amyloid deposition.
Notably, the researchers did not find a strong connection between amyloid deposition and levels of current cognitive activity alone.
"What our data suggests is that a whole lifetime of engaging in these activities has a bigger effect than being cognitively active just in older age," said Landau.
The researchers are careful to point out that the study does not negate the benefits of kicking up brain activity in later years.
"There is no downside to cognitive activity. It can only be beneficial, even if for reasons other than reducing amyloid in the brain, including social stimulation and empowerment," said Jagust. "And actually, cognitive activity late in life may well turn out to be beneficial for reducing amyloid. We just haven't found that connection yet."



El pico máximo de la gripe se espera en España para finales de este mes



El virus de la gripe necesita un ambiente frío y seco, como un buen Martini, y cuenta ahora con las condiciones perfectas para expandirse. Los últimos datos de la Red Nacional de Vigilancia Epidemiológica muestran cómo la infección invernal se ha intensificado este mes y alcanza ya una situación epidémica en el centro del país y algunos puntos del Norte. En la segunda semana de febrero, Madrid, Castilla-La Mancha, sur de Extremadura y algunos puntos del norte de España tenían los niveles más altos de intensidad gripal. Cantabria, según datos regionales —no publicados aún por la red nacional— tiene ya una situación epidémica. En Andalucía, Aragón, Cataluña y Navarra y La Rioja, la intensidad de la gripe aún es media. Aunque está en aumento en toda la Península. Solo se libran de la gripe Canarias y Melilla.
El pico máximo de la gripe se alcanzará previsiblemente a finales de este mes.
Tres muertes
Esta temporada la infección no distingue edades. Aumenta en todos los grupos, aunque es significativo en los menores de 65 años. La edad sí que cuenta en la gravedad de los casos. Desde que comenzó la temporada de gripe el otoño pasado se han registrado 28 casos graves en seis comunidades autónomas que han necesitado hospitalización y tres muertes debidas a la infección, todos mayores de 44 años. Dos de los fallecidos tenían factores de riesgo, susceptibles de sufrir una complicación severa por la gripe. En general, los problemas más graves se han registrado en niños muy pequeños, entre 1 y 4 años, y entre los más mayores, a partir de los 64. En casi todos los casos, los pacientes presentaban factores de riesgo, como son las enfermedades cardiovasculares y respiratorias. El 96,4% correspondieron a infecciones por el virus de la gripe A , que llegó a España para quedarse.
En el resto de Europa la intensidad de la actividad gripal era aún baja, durante la primera semana de febrero. Se ha detectado en Italia, Suecia, Holanda, Noruega y Reino Unido, aunque está en claro aumento, como en España. La buena noticia es que hasta el momento, los virus gripales que circulan por el continente europeo no muestran resistencias a los antivirales específicos para su tratamiento, oseltamivir (tamiflu) y zanamivir.






**Publicado en "ABC"

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