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Archive - May 8, 2009

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Alcohol Flushing Response May Indicate Cancer Risk

The alcohol flushing response, seen in approximately 36% of East Asians (Japanese, Chinese, and Koreans), may be an indictor of a much increased risk of esophageal cancer from alcohol consumption in these individuals, according to a recent article in PLoS Medicine. This is particularly unfortunate as esophageal cancer is one of the deadliest cancers worldwide, with five-year survival rates of 15.6% in the United States, 12.3% in Europe, and 31.6% in Japan, the authors noted. The flushing response is predominantly due to an inherited deficiency in the enzyme alcohol dehydrogenase 2 (ALDH2), and there is accumulating evidence that individuals deficient in ALDH2 are at a much higher risk of esophageal cancer than are those with normal levels of ALDH2. The authors advised that doctors should counsel their ALDH2-deficient patients to limit alcohol consumption and thereby reduce the risk of developing esophageal cancer. Clinicians can determine ALDH2 deficiency simply by asking about previous episodes of alcohol-induced flushing. As a result, ALDH2-deficient patients can then be counseled to reduce alcohol consumption, and high-risk patients can be assessed for endoscopic cancer screening. In view of the approximately 540 million ALDH2-deficient individuals in the world, many of whom now live in Western societies, even a small percent reduction in esophageal cancers due to a reduction in alcohol drinking would translate into a substantial number of lives saved, the authors asserted. [PLoS Medicine article]

Gecko’s Night Vision May Be Basis for Better Cameras, Contact Lenses

The key to the exceptional night vision of the nocturnal helmeted gecko is a series of distinct concentric zones of different refractive powers, according to a study published in the online Journal of Vision. Nocturnal geckos are among the very few living creatures able to see colors at night. "We were interested in the geckos because they, and other lizards, differ from most other vertebrates in having only cones in their retina," said project leader Dr. Lina Roth of Lund University in Sweden. "With the knowledge from the gecko eyes, we might be able to develop more effective cameras and maybe even useful multifocal contact lenses." The nocturnal gecko’s multifocal optical system is comprised of large cones, which the researchers calculated to be more than 350 times more sensitive than human cone vision at the human color vision threshold. The nocturnal gecko’s optical system gives them an advantage because light of different ranges of wavelengths can be focused simultaneously on the retina. Another possible advantage is that their eyes allow them to focus on objects at different distances. Therefore, the multifocal eye would generate a sharp image for at least two different depths. Geckos that are active during the day do not possess the distinct concentric zones and are considered monofocal, the researchers said. [Press release] [Journal of Vision abstract]