Letters.Antioxidants Antioxidants Substances that reduce the damage of the highly reactive free radicals that are the byproducts of the cells. Mentioned in: Aging, Nutritional Supplements antioxidants, n. ups and downs ups and downs pl.n. Alternating periods of good and bad fortune or spirits. ups and downs Noun, pl alternating periods of good and bad luck or high and low spirits The article "Antioxidants may help cancers thrive" (SN: 1/1/00, p. 11) would better have been titled "Deprivation of dietary antioxidants leads to selective tumor inhibition." The issue of antioxidants and cancer is an area of controversy, but the great preponderance of literature on this subject supports the use of antioxidants as sole therapy and with conventional oncologic care. These effects have had limited usefulness in human cancer treatment, however. Although deprivation of antioxidants may increase apoptosis in cancer cells, so may administration of exogenous antioxidants such as melatonin melatonin: see pineal gland. melatonin Hormone secreted by the pineal gland of most vertebrates. It appears to be important in regulating sleeping cycles; more is produced at night, and test subjects injected with it become sleepy. , vitamin A, flavonoids flavonoids, n.pl common plant pigment compounds that act as antioxidants, enhance the effects of vitamin C, and strengthen connective tissue around capillaries. , and vitamin E. Davis W. Lamson and Matthew S. Brignall Kenmore, Wash. Whose genes, and where? In sequencing the human genome ("One down: A human chromosome sequenced," SN: 12/4/99, p. 356), what is used as a blueprint so as to avoid sequencing mutations? Nicholas L. Seachord Washington, Kan. From the U.S. office of the international Human Genome Project. "The human genome reference sequence will not represent an exact match for any one person's genome. Samples from several different anonymous individuals comprise a genome library that is used for sequencing. The DNA DNA: see nucleic acid. DNA or deoxyribonucleic acid One of two types of nucleic acid (the other is RNA); a complex organic compound found in all living cells and many viruses. It is the chemical substance of genes. in the libraries is gathered from sperm (male) and blood (female).... Ultimately, an estimated 10 to 20 individuals will have their DNA used extensively in producing the first reference genome sequence." This reference genome may well contain individual mutations, but identifying such genetic variability is the next major task for geneticists This is a list of people who have made notable contributions to genetics. The growth and development of genetics represents the work of many people. This list of geneticists is therefore by no means complete. Contributors of great distinction to genetics are not yet on the list. . Since the DNA comes from apparently healthy people, those mutations presumably pre·sum·a·ble adj. That can be presumed or taken for granted; reasonable as a supposition: presumable causes of the disaster. aren't harmful. --J. Travis I find the headline and article kind of silly. What kind of news is it to say chromosome 22 is the first human chromosome to almost be fully sequenced? Further down in the article you say: "Twenty-two pairs of chromosomes, plus the X and Y chromosomes, carry almost all of a person's genes." Almost? My decades-past college biology course didn't mention anyplace else where humans had genes. Michael Sakarias Juneau, Ark. Mitochondria, the energy-producing organelles within cells, carry a small number of genes separate from those in the cell nucleus. --J. Travis |
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