lunes, agosto 28, 2006

Videos estres y cerebro

Estrés y placer, extremos encontrados
Clip de la entrevista de Eduard Punset con el biólogo Robert Sapolsky. Más
información en texto en smartplanet.
video en youtube

'Stress, Neurodegeneration and Individual Differences' by Robert Sapolsky
video en Google


domingo, agosto 27, 2006

Articulo en Quo

Un artículo con varias cosas criticables, pero como para lerlo:

Recarga tu mente        

¿Hasta dónde llegarías para sacar el máximo partido a tu cerebro?
El doping intelectual es ya una tentación a tu alcance.


viernes, agosto 25, 2006

Fechas de vencimiento de los suplementos y drogas

Q Is there any problem in taking vitamins a year or so past the expiration date? Are there specific vitamins that would deteriorate so much that one shouldn’t take them?

A This is a commonly asked question, and the answer must be qualified. Regarding drugs, the FDA has monitored what they call the shelf life extension program (SLEP) of drugs for the past 20 years for the United States Department of Defense.1 Extensive pharmaceutical stability data indicate that in 88% of the drugs tested (122 in all, representing 3005 different lots), shelf life was extended for at least one year beyond the originally indicated expiration date—and by an average of 66 months! However, there was a lot of variability during the extended period, and the FDA reported that the only way to be assured of continuing potency was through periodic testing and systematic evaluation of each lot.

Regarding supplements such as vitamins, minerals, amino acids, and other nutrients, no large study has ever been undertaken, as far as I know. (With all that testing, the cost of the SLEP study must have been staggering!) But we do know, from stress and stability studies of individual supplements, that there is a great deal of variability, just as there was in the SLEP study.

The principal factor that determines shelf life is initial quality. The supplement must have essential material as much as is reasonably possible and, by the same token, low levels of nonessential material. It must also have low levels of prooxidative residues, as little moisture as possible, and, if synthesized (as most vitamins are), great chemical stability. Herbal materials must have nearly unmeasurable levels of bacteria or be sterilized. The supplement must be packaged in opaque and secure containers in a clean or sterile, dust-free, air-conditioned, dehumidified environment and not be subjected to extremes in temperature. Finally, as you have undoubtedly seen on the labels, the supplements should be stored in a cool, dark, dry place.

Products made under the above conditions, if stored properly in unopened bottles, should last at least two years before any loss of potency occurs, and, once opened, they should hold up for at least one year.

Initial quality is paramount. For example, the vitamin C developed by Hoffmann-La Roche has been found to outlast other vitamin C products by many years (unopened samples have maintained their purity and potency for up to 20 years). Other vitamin C products have been found to darken, changing color from brown to gray to black in only a few years. This darkening reflects the formation of dehydroascorbic acid, an oxidized form of vitamin C that is undesirable to ingest. Life Enhancement Products uses only vitamins manufactured by the successor company to Hoffmann-La Roche, as well as amino acids, hormones, herbs, and other supplements from the world’s premium producers.

Lyon RC, Taylor JS, Porter DA, Prasanna HR, Hussain AS. Stability profiles of drug products extended beyond labeled expiration dates. J Pharm Sci 2006 Jul;95(7):1549-60.

Supplement Expiration Dates: How Reliable Are They?

jueves, agosto 17, 2006

BBC - Radio 4 Memory Experience - Improve your memory

BBC - Radio 4 Memory Experience - Improve your memory: "Tips and techniques to improve your memory
Memory Strategies - do what the experts do!

Memory isn't like a muscle, something specific you can exercise. It's a way of organising information in your brain. So to improve your memory, you need to change and re-organise the way you think and this will help to support how your memory works."

martes, agosto 08, 2006

Curcuma para el Alzheimer

En hay una nota en Español que pongo abajo sobre lo que mencioné antes de la curcumina y el Alzheimer:

El pigmento del curry, nueva esperanza para el Alzheimer

La curcumina (Curcuma longa, azafrán de Las Indias), pigmento amarillo utilizado en la elaboración del polvo de curry, podría constituir una nueva esperanza en el tratamiento de la enfermedad de Alzheimer. La revista Journal of Biological Chemistry publica en su edición preliminar online un estudio de investigadores de la Universidad de California en Los Ángeles que muestra cómo la curcumina inhibe in vivo la formación de ß-amiloide (ßA).

La curcumina ya ha demostrado con anterioridad fuertes propiedades antiinflamatorias y antioxidantes, siendo capaz de suprimir el daño oxidativo, la inflamación, los déficit cognoscitivos y la acumulación de amiloide.

Dado que la estructura molecular de la curcumina sugería su potencial de ligarse al ßA, los autores de este estudio decidieron investigar si su eficacia en modelos de enfermedad de Alzheimer podría explicarse mediante sus efectos sobre la agregación del ßA.

Bajo condiciones de agregación in vitro, la curcumina no sólo inhibe la agregación, sino que también muestra poder de desagregación del ßA(40) fibrilar, indicando una estequiometría favorable para la inhibición. Demostró ser mejor inhibidor de la agregación del ßA(40) que el ibuprofeno y el naproxeno, e impidió la formación y toxicidad del oligómero ßA(42). Estos efectos de la curcumina no dependían de la secuencia del ßA, sino de su conformación fibrilar. Unos cortes cerebrales incubados con curcumina, procedentes de ratones transgénicos modelo de enfermedad de Alzheimer, revelaron un marcado preferencial de la placas de amiloide.

Los estudios in vivo demostraron que la injección de curcumina por vía periférica atravesaba la barrera hematoencefálica y se ligaba a las placas de amiloide en ratones transgénicos de avanzada edad. Usada como alimento en viejos ratones transgénicos Tg2576 (un modelo transgénico de enfermedad de Alzheimer) con avanzada acumulación de amiloide, la curcumina marcaba las placas y reducía tanto los niveles de amiloide como la carga de placas.

Por lo tanto, la curcumina se liga al ßA bloqueando su agregación y su conformación fibrilar, tanto in vitro como in vivo.

Los autores afirman en sus conclusiones que ". . . Estos datos sugieren que la curcumina a dosis bajas desagrega eficazmente el ßA evitando también la formación de fibrillas y oligómeros, respaldando la argumentación para el uso de la curcumina en ensayos clínicos de prevención o tratamiento de la enfermedad de Alzheimer".

F. Yang et al. Curcumin inhibits formation of Aß oligomers and fibrils and binds plaques
and reduces amyloid in vivo. J Biol Chem 2004, 10.1074/jbc.M404751200

La curcuma mejora el cerebro en ancianos

Popular curry spice is a brain booster
04 August 2006
From New Scientist Print Edition. Subscribe and get 4 free issues.

Call it yellow ginger, haldi, turmeric or E100, the yellow root of Curcuma longa, a staple ingredient in curry, is turning out to be gratifyingly healthy. Now Tze-Pin Ng and colleagues at the National University of Singapore have discovered that curry eating seems to boost brain power in elderly people.

Curcumin, a constituent of turmeric, is an antioxidant, and reports have suggested that it inhibits the build-up of amyloid plaques in people with Alzheimer's. Ng's team looked at the curry-eating habits of 1010 Asian people unaffected by Alzheimer's and aged between 60 and 93, and compared their performance in a standard test of cognitive function, the Mini Mental State Examination. Those people who consumed curry "occasionally" (once or more in 6 months but less than once a month) and "often" (more than once a month) had better MMSE results than those who only ate curry "never or rarely" (American Journal of Epidemiology, DOI: 10.1093/aje/kwj267).

"What is remarkable is that apparently one needs only to consume curry once in a while for the better cognitive performance to be evidenced," says Ng, who says he wants to confirm the results, possibly in a controlled clinical trial comparing curcumin and a placebo.
From issue 2563 of New Scientist magazine, 04 August 2006, page 18

lunes, agosto 07, 2006

Caidas en ancianos pueden indicar problemas cerebrales

Hay una interesante nota en que explica que ciertas lesiones cerebrales como hemorragias producidas por golpes (aún golpes leves o movimientos bruscos de la cabeza en un cerebro que ya está afectado por el encojimiento, lo que produce tensión en los vasos sanguíneos que pueden sangrar), pueden ser la causa de caídas o cambios del comportamiento. Se requiere atención para evitar el paso de tiempo sin atender el problema de base.

As the years go by, the adult brain slowly atrophies, like a desiccated orange detaching from its rind. The shrinkage can cause problems. Cerebral veins are tethered to the superior sagittal sinus, the large blood vessel that runs front to back along the underside of the skull. As the brain contracts, these bridging veins must stretch, making them vulnerable to shearing forces caused by rapid head movements or even modest contusions. Without sufficient brain tissue to support and compress the bleeding site, small, low-pressure venous leaks may go unstanched. The blood seeps into the gap between the arachnoid membrane that encloses the brain and the lining of the skull, or dura mater. Bleeding into this space is called a subdural hematoma.

Acute subdural hematomas result from severe head trauma and expand quickly. Chronic subdural hematomas, on the other hand, often spread slowly—and without visible symptoms. What really scares emergency physicians—and has me repeating to patients and their families, "Return if there's any change in behavior"—is that older people who have fallen can look fine for weeks before the bleeding causes symptoms. By then, relatives will have forgotten the long-ago head knock, attributing Granddad's confusion to the heat, the cold, or a dizzy spell. Without that critical, sometimes lifesaving clue, precious time is lost.

Vital Signs: Why is Grandpa Falling?    
A seemingly simple stumble provides clues to serious injury.    
By Tony Dajer   
DISCOVER Vol. 27 No. 08 | August 2006 |

miércoles, agosto 02, 2006

Suplementos para el deterioro mental

Monday, July 31, 2006
Dietary supplements for mental decline (Alzheimer's)

Knowledge of Health, Inc., Blog – August 1, 2006: So mom’s in the nursing home, loaded up with ineffective drugs to help overcome signs of senility and memory loss, plus other drugs for blood pressure and circulation. A small study of 35 such patients (average age 71 years) shows that the addition of dietary supplements (multivitamin, vitamin E, lipoic acid, coenzyme Q10, omega-3 oils) along with physical exercise and sound dietary measures slowed the decline in brain function and actually improved memory and other brain functions. [American Journal Alzheimer’s Disease 20: 21-26, 2005] Now all you have to do is get the doctor to go along with the idea. –Copyright 2006 Bill Sardi, Knowledge of Health, Inc.

martes, agosto 01, 2006

Alimentos que deprimen o estimulan

Según la Médico naturista Albertinazi (en una entrevista con Chiche Gelblung por radio) hay alimentos de deprimen o estimulan.

Deprimen (o mejor dicho sedan):

Azúcar blanco
Demasiada proteína cansa
vegetales verdes, sedantes por contener vitamina B6
tronco de la lechuga

, ponen alegre:

ácidos grasos Omega 3, de pescado de aguas frías (que comen Krill) o de semillas de lino, semillas de chía u hojas verdes. Las semillas agregadas al pan pierden los omega en la cocción.
alimentos crudos dan energía (fruta, zanahorias, repollo crudo, no el repollo fermentado que sin embargo mejora la digestión)
jengibre da energía pero eleva la presión, se puede tomar una cucharadita por día o en té para los resfríos