Mostrando entradas con la etiqueta Biotecnología. Mostrar todas las entradas
Mostrando entradas con la etiqueta Biotecnología. Mostrar todas las entradas

Descubren cómo se reorganiza el cerebro después de un trasplante de manos por Antonio Martínez Ron

En el año 2008,  Chris Pollock perdió las dos manos en un accidente mientras manipulaba su tractor. Cuatro años después puede agarrar cosas y ha recuperado parte del tacto gracias a un pionero trasplante de manos realizado en el hospital de Pittsburgh (Pennsylvania, EEUU). "Al principio no sientes nada, tienes que adivinarlo todo", aseguraba Pollock al programa Good Morning America, "pero ahora coges cosas sin darte cuenta de que lo estás haciendo".


El éxito de este tipo de operaciones llevó a un grupo de científicos del mismo hospital a interesarse por el proceso de reconexión neuronal que se produce tras el trasplante de un miembro. El equipo del doctor Anto Bagić, en colaboración con el grupo de Fernando Maestu en el Centro de Tecnología Biomédica de la Universidad Politécnica de Madrid, ha analizado durante un año la evolución de dos sujetos que recibieron un trasplante de manos y ha descubierto el proceso por el cuál se recupera la conexión neuronal con los nuevos miembros.




El primer paciente, Chris Pollock, de 41 años, fue objeto de un doble trasplante: un brazo a la altura del codo y una mano. El segundo esJoshua Maloney, un ex marine de 24 años que perdió una mano en la invasión de Iraq de 2003 cuando un compañero activó por error una carga explosiva. Tras una operación de 11 horas, el doctor Andrew Lee le implantó la mano de un donante en una de las primeras intervenciones de este tipo en EEUU.
Un proceso de un año
"Hemos medido el tiempo de reacción del cerebro a distintos estímulos de presión y contacto en dos grupos de personas, el primero con manos propias y el segundo con manos trasplantadas", explica  Bagić a lainformacion.com. "La señal, que es mucho más lenta en los miembros trasplantados, mejora sensiblemente con el tiempo y se aproxima a la de los sujetos sanos al cabo de un año". Con ayuda del equipo español, los investigadores han medido también la reorganización a nivel cerebral de las señales y han descubierto el proceso por el que la mano trasplantada se va integrando de nuevo en el cerebro.
Evolución de las conexiones tras el trasplante de la mano derecha.
El cerebro debe comunicarse físicamente con la nueva mano, explica Anto Bagić, y los nervios deben ir creciendo para restablecer las conexiones. "El nervio crece aproximadamente un milímetro por día", asegura el investigador. Mediante resonancia magnética funcional y magnetoencefalografía los investigadores han observado este proceso gradual de recuperación de estímulos entre el cerebro y el miembro trasplantado. "A medida que transcurren los meses", apunta Bagić, "el cerebro recupera las conexiones y el trasplante es más funcional".
La investigación también ha permitido medir una asimetría en la recuperación según el segmento amputado. El brazo trasplantado a la altura del codo tardó más tiempo en ser funcional que la mano, puesto que los nervios receptores tienen que crecer una distancia mayor para alcanzar la mano, según Bagić. "Un trasplante más corto", resume, "se hace funcional en menos tiempo".
Seguir leyendo en La información.




Africa needs biotech crops


In a strongly worded editorial in Science magazine this week, Calestous Juma, the director of the Agricultural Innovation in Africa program at Harvard's Kennedy School, called for a government-led initiative to introduce biotechnology into Africa. "Major international agencies such as the United Nations have persistently opposed expanding biotechnology to regions most in need of its societal and economic benefits," he wrote.
Genetic modification has had a huge impact on agriculture worldwide. More than 15 million farmers now plant GM crops on almost 370 million acres, boosting yields by 10% to 25%. Despite opponents' fears that the technology would poison people, spread superweeds and entrench corporate monopolies, it's now clear that the new crops have reduced not only hunger but pesticide use, carbon emissions, collateral damage to biodiversity and rain-forest destruction.
Yet, while much of North and South America, Australia and Asia are expanding the use of GM crops, only three African countries have adopted them (a further four are conducting trials). Mr. Juma argues that Africa is the place that most needs a boost from biotech: Many of the continent's farmers cannot afford to buy pesticides, so corn and cotton that are genetically insect-resistant could make a big difference there. Over the past five decades, while Asian yields have quadrupled, African yields have barely budged.
Yet political squeamishness abounds. In an article this week for the Alliance for a Green Revolution in Africa (AGRA), John Kufuor, the former president of Ghana, argued that "Africa's agriculture has been cut off from the scientific advances which have transformed yields in many other parts of the globe"—but he did not mention GM crops. AGRA, whose chairman is former U.N. Secretary-General Kofi Annan, says that the group "does not fund the development of GM crops."
Africa grows a diverse range of crops as staple foods: not just corn, rice and wheat but cassava, yams, black-eyed peas and bananas. Genetic modification has so far focused mainly on the big commercial crops. Ironically, this is because of immensely complex biosafety regulations demanded by environmental pressure groups in the West, which don't apply to crop varieties produced by other means, including mutation by irradiation.
Only big firms can afford this ordeal by red tape, and only for big crops. The pioneering Swiss biologist Ingo Potrykus, who has watched his not-for-profit invention of vitamin-enhanced "golden rice" tied up for 13 years by regulatory procrastination, is no longer in the mood to mince words. He recently wrote that he holds "the regulation of genetic engineering responsible for the death and blindness of thousands of children and young mothers."
Biotechnology's potential in Africa is illustrated by the case of the black-eyed pea, a crop that is attacked by an insect called the Maruca pod borer, which causes $300 million in annual losses to small-scale farmers there and can be controlled only with expensive pesticides that many cannot afford. A university in Nigeria has developed an insect-resistant GM black-eyed pea, but Nigeria does not allow the commercial use of GM crops.
In Uganda, where people often eat three times their body weight in bananas a year, a GM banana that is resistant to a bacterial wilt disease, which causes $500 million in annual losses and cannot be treated with pesticides, is being tested behind high security fences. The fences are there not to keep out anti-GM protesters, as in the West, but to keep out local farmers keen to grow the new crop.
"By creating institutions such as the Convention on Biological Diversity that seek to smother biotechnology at birth," Calestous Juma tells me, "sections of the U.N. are no more than the Pontius Pilate of innovation."

Bioengineering Methuselah. Nick Shulz




Extracts:

Scientists across the world, Ms. Arrison says, are working on engineering close to two dozen different human organs in the lab, including bladders, lungs and hearts. Progress is slow, and it might be decades before bioengineered organs are commonplace, but the trend-line is clear. A force behind the movement is the U.S. military, an eager funder of restorative and regenerative engineering. Dr. Robert Vandre, chairman of the Armed Services Biomedical Research Evaluation and Management Committee, thinks that "ultimately, we will be able to grow limbs" for wounded soldiers.


And if humans do begin living to 150, then what? If Medicare and Social Security are in trouble now, what happens when they must support multiple generations of retirees? In Ms. Arrison's mind, we'll be living healthy, productive working lives until very near the end. The more pressing concerns, for her, have to do with the strain on natural resources and the added pollution of a swelling world population.



Biotech Beets Banned by Ronald Bailey‏

Beet ban will hurt farmers while strengthening massive seed monopolies

Last week, a federal district court judge in northern California issued an injunction against planting biotech sugar beets next year. Why? He accepted the activist argument that the U.S. Department of Agriculture (USDA) must issue a full environmental impact statement (EIS) under the National Environmental Policy Act before permitting the improved sugar beets to be grown. An EIS is required when a federal government agency engages in actions that might be "significantly affecting the quality of the human environment."

So how are biotech sugar beets (already approved by the USDA, mind you) significantly affecting the human environment? Activists at the Center for Food Safety and the Sierra Club argued in federal court that sugar beets improved to resist the herbicide glyphosate might result in the development of superweeds or might interbreed with organic chard and regular beets.

Let’s consider a few background facts. Sugar beets are the source of half the sugar produced in the U.S. Biotech sugar beets were approved as safe for growing by the USDA five years ago. The frankenbeets at issue in this case are now so popular with farmers that they constitute 95 percent of the current crop. In fact, there may not be enough conventional seeds to replace biotech seeds for next year’s planting.

Meanwhile, weeds treated with any herbicide tend to become resistant to those that are applied to them, this is not something peculiar to biotech plants. And most sugar beets are grown nowhere near organic chard or red beets and so will have no chance to interbreed with them. (Even if they did, sugar beets are typically harvested before they flower and so don’t get a chance to produce pollen in the first place.)

In the bigger picture, it might be fair to ask why regular farmers who are growing biotech crops are forced to worry about meeting unscientific process standards that organic farmers have imposed on themselves. If organic farmers insist on no cross pollination from biotech crops, they can pay local beet farmers to grow something else or look into other options besides an across the board ban. The U.S. government has also subsidized the production of sugar from beets and limits the import of sugar from cheaper foreign producers, so if anti-biotech activists really want to substantially cut the growing of biotech beets, opposition to sugar subsidies and sugar import tariffs might be a better place to start.

More worryingly, these unscientific attacks on agricultural biotechnology are producing another consequence that the same anti-biotech activists often decry—the increasing consolidation of the seed industry over the past two decades.

I regularly cover activist gatherings at which the biotech agriculture company Monsanto is denounced as the devil incarnate. Why? Because the St. Louis company is allegedly monopolizing seeds. Last year Dupont, which owns Pioneer Hybrid Seeds, a big competitor of Monsanto, claimed in filings with the U.S. Justice Department that 95 percent of all the soybeans and 60 percent of all the corn planted in the U.S. contained genes licensed from Monsanto. Monsanto responded that it actually sold a much lower percentage of seeds on the market, although the company admitted that most independent seed companies licensed and sold seeds using its herbicide and insect resistant traits. In fact, biotech crop varieties are so popular with American farmers that seeds for non-biotech corn, cotton, and soybeans constituted only about 13 percent of the varieties offered last year.

Decades ago there were hundreds of seed companies competing for farmers’ business. Now the U.S. seed market is dominated by Monsanto, Dupont, and Syngenta, which sell more than 40 percent of seeds for all major crops in the U.S. In the 1990s, agricultural chemical companies began to integrate with seed companies, offering farmers very attractive packages of high quality seeds and the chemicals that would protect them from weeds. How attractive? As one California cotton farmer explained recently to Forbes magazine, his organic fields cost $500 per acre to weed by hand while killing weeds by spraying Monsanto’s glyphosate on his biotech herbicide resistant cotton fields costs only $30 an acre.

This process of consolidation is being substantially abetted by the growing web of regulations and litigation pushed by anti-biotech activists. Already biotech crops must pass muster through the USDA, the Environmental Protection Agency, and the Food and Drug Administration for health and environmental safety. The system is becoming almost as complicated and onerous as the gauntlet that pharmaceutical companies must run in order to get their products to patients. By treating crops like drugs, the government and activists make sure that getting them approved costs ever more. “The result is that only large firms, pursuing high-value commodity crops are willing to front the money to get a transgenic crop approved for commercial cultivation,” notes Gregory Conko, a Competitive Enterprise Institute policy analyst and co-author of The Frankenfood Myth: How Protest and Politics Threaten the Biotech Revolution. Conko adds, “The EIS requirement will, of course, add considerably to the time and expense of getting a crop through the regulatory apparatus.” Monsanto's shareholders will be the biggest beneficiaries.

Unlike drugs which can sell for beaucoup bucks, crops are commodities that sell for dollars per bushel. So only big companies can marshal the financial and legal resources required to get approval for crops that sell by millions of bushels and bales, corn, soybean, canola, and cotton. Meanwhile the biotech improvement of smaller niche crops, say tomatoes and green beans, that might benefit even backyard gardeners remains stymied.

Conko also points out, “The EIS requirement long ago ceased being just about a look at likely ecological impacts, and now must include any and all potential effects on the ‘human environment’. Courts interpret that to include economic effects, social effects, what have you.” Of course, new crop varieties will have economic and social effects—they’re supposed have economic and social effects, e.g., lower production and food costs. Clearly, the National Environmental Policy Act must be reined in, but in the meantime the USDA should pursue a comprehensive environmental impact statement that can scientifically demonstrate to meddlesome judges that new biotech crop plants do not significantly affect the human environment and therefore an individual impact statement is not required for each new variety.

Ultimately, biotech crops should not be subject to any more regulatory scrutiny than any other crop varieties. Making those changes would go a long way toward breaking up the nascent seed monopolies that the overregulation favored by anti-biotech activists has produced.

Ronald Bailey is Reason's science correspondent. His book Liberation Biology: The Scientific and Moral Case for the Biotech Revolution is now available from Prometheus Books.

Disclosure: I think I am still some kind of adjunct fellow at CEI. Many years ago I owned some Monsanto stock. I probably should have held on to it.