August 15th, 2011 by admin

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Herceptin, or Trastuzumab is employed to treat certain types of breast cancer with high efficiency. The drug consists of a monoclonal antibody raised against a protein called Her2, which is highly abundant in some tumours with high probability of migrating and becoming metastatic. Tumours found to have high levels of her2 are called “Her2 positive“. When injected the drug binds to the surface of the tumour cells that have Her2 and make them an easy target for the immune system. Herceptin is used with increasing frequency but the costs associated to its use are very high. The high costs make it difficult to sustain long-term administration and thus the efficiency of the treatment may become compromised. Now, Canadian scientists have developed a method to produce Herceptin in tobacco plants. They inserted the genes encoding the antibody into special tobacco plants and let them grow. After a while, they crushed the leaves and purified active Herceptin in large amounts. They have tested their product and showed that is seems to work as well as the normal Herceptin. This exciting study brings big hopes as it will help bring down the costs of the expensive Herceptin treatments.
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Category: Biology, Cancer, Chemotherapy, Medicine, Oncology |
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April 14th, 2008 by admin
Humans love the taste of sugar so much that the word “sweet” refers not only to this basic taste quality but also something that is highly desirable or pleasurable. This attraction goes so far that sugar (and sugar-rich foods) overconsumption is probably the main factor driving the current obesity epidemic.
But why are we so fond of sugar, when other animals appear to be so ‘self-restrained’ when it comes to diet and nutrition? The answer seems to lie on our evolutionary history. Refined sugars (e.g., sucrose, fructose) were absent in the diet of most people until very recently in human history. Biologists speculate that the human attraction for intense sweetness results from an inborn hypersensitivity to sweet tastants (molecules that taste sweet). In most mammals, including rats and humans, sweet receptors evolved in ancestral environments poor in sugars. Being able to detect carbohydrate-rich nutrients constituted an advantage that was selected favourably as it allowed to choose foods more effective in providing energy. However, natural foods are usually sugar-poor, so our ancestors were not not adapted to the high concentrations of sweet tastants present in our present-day products that contain refined sugar or corn syrup.

Overconsumption of sugar-dense foods or beverages is initially motivated by the pleasure of sweet taste and is often compared to drug addiction. French investigators attempted to explore this relationship by using rats that were offered either sweetened water or highly addictive doses of cocaine. The results were stunning: the vast majority of the rats (94%) preferred the sweet treat over the drug, demonstrating that intense sweetness can surpass cocaine reward, even in drug-sensitized and -addicted individuals.
A plausible explanation for the addictive power of sugar is that the supranormal stimulation of the sweet receptors by sugar-rich diets, such as those now widely available in modern societies, would generate a supranormal reward signal in the brain, with the potential to override self-control mechanisms and thus to lead to addiction.
Category: Addictions, Biology, Diabetes, General health, Medicine, Obesity, Weightloss |
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