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LE Magazine May 1999

MEDICAL UPDATES

Studies from throughout the world that can help you live longer

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May 1999
Table Of Contents
 
  1. Vitamin D3 and human Melanoma cells
  2. Dietary flavonoids interact with endogenous antioxidants
  3. Vitamin E reverses the age-related deficit in brain
  4. Tea extracts inhibit lung cancer cell growth
  5. DHEA inhibits smooth muscle proliferation
  6. Tea antioxidants in cancer chemoprevention
  7. Amantadine as treatment for Parkinson's disease
  8. Risk of Parkinson's disease with farming
  9. Bone mineral density and GH replacement therapy
  10. Effects of multivitamins on HIV-infected women
  11. Foods, beverages and gastric cancer
  12. Inhibition of ultraviolet B damage by Genistein
  13. Use of percentage Free PSA in prostate cancer detection
  14. Deprenyl protects against brain cell death
  15. Aspirin cuts death rate among diabetics
  16. Cranberry extract inhibits LDL oxidation
  17. Curcumin inhibits free radical generation in leukocytes
  18. Lycopene uptake and tissue disposition
  19. Role of tomato products in disease prevention
  20. Vitamin D3 protects against kidney damage
  21. Nutritional status with Crohn disease
  22. Phyto-oestrogens: Where are we now?
  23. Dietary fat and advanced prostate cancer

  1. Vitamin D3 and human Melanoma cells

    Full source: Cell Adhesion and Communication, 1998, Vol. 5, Iss 2, pp 109-120

    In the present investigation, the effect of vitamin D3 on melanoma cells was examined. Melanoma cell proliferation was shown to be inhibited in response to the vitamin D3. After exposure for 6 days, it was found that the level of receptors on the melanoma cell surface was reduced by more than 40%. This was accompanied by a reduced ability of the cells to adhere to an artificial basement membrane. In conclusion, the present investigation shows that besides having an antiproliferative effect on melanoma cells, vitamin D3 is also able to inhibit the surface cell receptors.



  2. Dietary flavonoids interact with endogenous antioxidants

    Full source: Biochemistry and Molecular Biology International, 1998, Vol. 44, Iss 5, pp 1069-1074

    Green tea catechins (flavonoids) were given to healthy volunteers under a controlled diet for four consecutive weeks. Plasma concentrations of ascorbate, urate, alpha-tocopherol, beta-carotene, and blood levels of total glutathione were measured. The results showed that catechin intake provided antioxidant protection through a cascade involving antioxidants originating in the body. Vitamin E and beta-carotene were spared by the catechins, resulting in an overall protection against oxidative modification of red blood cell membrane polyunsaturated fatty acids (PUFA).



  3. Vitamin E reverses the age-related deficit in brain

    Full source: Journal of Biological Chemistry, 1998, Vol. 273, Iss 20, pp 12161-12168

    Long term potentiation (LTP) in the hippocampus of the brain is impaired in aged rats, and this has been associated with an age-related decrease in membrane arachidonic acid concentration. Groups of aged and young rats were fed a) a diet supplemented with Vitamin E or b) a control diet, and assessed for their ability to sustain LTP. Aged rats fed on the control diet exhibited an impaired ability to sustain LTP. Tissue prepared from these rats exhibited increased interleukin-1 beta, increased lipid peroxidation, and decreased membrane arachidonic acid concentration compared with young rats fed on either diet. However, aged rats fed on the supplemented diet sustained LTP in a manner indistinguishable from young rats. The age-related increases in interleukin-1 beta and lipid peroxidation and the decrease in membrane arachidonic acid concentration were all reversed. The observation that vitamin E reverses these changes supports the hypothesis that some age-related changes in the brain might come from oxidative stress.



  4. Tea extracts inhibit lung cancer cell growth

    Full source: Carcinogenesis, 1998, Vol. 19, Iss 4, pp 611-616

    The growth inhibitory effects of tea preparations and purified tea polyphenols were investigated using four human cancer cell types. The green tea catechins, made up of epigallocatechin-3-gallate (EGCG) and epigallocatechin (EGC), displayed strong growth inhibitory effects against lung tumor cells. The results suggested that the growth inhibitory activity of tea extracts is caused by the activities of different tea polyphenols. Tea polyphenols induce the production of hydrogen peroxide (H2O2), which may mediate cell death, and this may contribute to the growth inhibitory activities of tea polyphenols.



  5. DHEA inhibits smooth muscle proliferation

    Full source: Journal of Pharmacology and Experimental Therapeutics, 1998, Vol. 285, Iss 2, pp 876-883

    DHEA has been shown to reduce the growth of immortalized and malignant cells. This study explored the effects of DHEA on the growth of smooth muscle cells in the trachea (air tube extending from the larynx into the thorax). An increase in the number of cells (hyperplasia) may lead to obstruction of the fixed airways and hyperresponsiveness in severe chronic asthma. DHEA dramatically reduced proliferation of rat smooth muscle cells in the trachea. DHEA caused a later DNA response important for expression of genes that mediate DNA synthesis and cell cycle progression. The results suggest that DHEA may impair activation of secondary tumor growth genes and may prove useful for treatment of asthma.



  6. Tea antioxidants in cancer chemoprevention

    Full source: Journal of Cellular Biochemistry, 1997, Suppl. 27, pp 59-67

    In recent years, the concept of cancer chemoprevention has matured greatly. Significant reversal or suppression of pre-malignancy by chemopreventive agents appears achievable. Tea is cultivated in about 30 countries, and is the most widely consumed beverage in the world. Three main commercial tea varieties are usually consumed, but most experimental studies demonstrating the anti-cancer effects of tea have been conducted with green tea extract. The majority of these studies have been conducted in mouse skin tumors. Green tea polyphenols (GTP) has been shown to exhibit anti-cancer activity and inhibit carcinogen and UV-induced skin cancer in humans. Tea consumption has also been shown to protect against chemical carcinogen-induced stomach, lung, esophagus, duodenum, pancreas, liver, breast, and colon cancer. Several polyphenols present in green tea have been shown to possess anti-cancer activity. The most active is epigallocatechin-3-gallate, which is also its major constituent. The mechanisms of broad cancer chemopreventive effects of tea are not completely understood. Some theories include a) inhibition of UV and ornithine decarboxylase, cyclo-oxygenase, and lipoxygenase activities, which are tumor promoters, b) antioxidant and free radical scavenging activity, c) enhancement of antioxidant glutathione, and d) inhibition of lipid peroxidation, and anti-inflammatory activity. These properties of tea polyphenols make them effective chemopreventive agents against the initiation, promotion, and progression stages of multistage cancer.



  7. Amantadine as treatment for Parkinson's disease

    Full source: Neurology, 1998, Vol. 50, Iss 5, pp 1323-1326

    Amantadine is a well-tolerated and modestly effective antiparkinsonian agent. This study looked at the effects of amantadine on dyskinesia (impairment of the power of voluntary movement) and motor fluctuations in Parkinson's disease. In 14 patients with advanced Parkinson's disease, amantadine reduced dyskinesia severity by 60% compared to placebo, without altering the antiparkinsonian effect of levodopa. Motor fluctuations occurring with patients' regular oral levodopa regimen also improved. These findings suggest that amantadine given in conjunction to levodopa can markedly improve motor response complications. Amantadine has for years been part of the Foundation's Parkinson's protocol.



  8. Risk of Parkinson's disease with farming

    Full Source: Neurology, 1998, Vol. 50, Iss 5, pp 1346-1350

    This study assessed exposure to pesticides, farming, well water use, and rural living as risk factors for Parkinson's disease (PD). It consisted of men and women greater than or equal to 50 years of age who had primary medical care at Henry Ford Health System in metropolitan Detroit. The results showed a significant association of occupational exposure to herbicides (95%) and insecticides (96%) with PD. No relation was found with fungicide exposure. Farming as an occupation was significantly associated with PD (97%), but there was no increased risk of the disease with rural or farm residence or well water use. The results suggest that Parkinson's disease is associated with occupational exposure to herbicides and insecticides and to farming.



  9. Bone mineral density and GH replacement therapy

    Full Source: Clinical Endocrinology, 1998, Vol. 48, Iss 4, pp 463-469

    Past studies have assessed the effects of long-term GH replacement therapy on bone mineral density (BMD) in patients with adult onset GH deficiency. To date no study has looked at the long-term impact on BMD after a short course (6-12 months) of GH replacement. This study observed BMD either (a) after 3 years of continuous GH replacement or (b) 2 years after completion of a short course of GH. Group A, (3 females) all received GH replacement continuously for 3 years. Group B, (8 females) 6 received GH replacement for 6 months and 2 received GH replacement for 12 months with BMD being measured at 6 monthly intervals. In group A, BMD had increased significantly by 3.7%. In group B, only trochanter BMD changed significantly, increasing by 5.9%. After completion of GH therapy, however, BMD increased significantly at lumbar spine, Ward's area and trochanter but not at the femoral neck or forearm. Thus, long-term (3 year) GH replacement therapy for three years appears to have beneficial effects on bone in patients with adult onset GH deficiency particularly at the lumbar spine and trochanter. A short course (6-12 months) of GH replacement therapy results in an increase in trochanter BMD several years later, and after an initial decline in BMD while on GH replacement, lumbar spine and Ward's area BMD return towards their starting values. These results emphasize that not all types of bone and skeletal sites respond to GH therapy identically. Furthermore, a short course of GH replacement over 6-12 months may result in significant changes in BMD several years later.



  10. Effects of multivitamins on HIV-infected women

    Full Source: Lancet, 1998, Vol. 351, Iss 9114, pp 1477-1482

    In HIV-infected women, poor micronutrient status has been associated with faster progression of HIV-1 disease and adverse birth outcomes. The effects of multivitamins and vitamin A on birth outcomes and counts of T lymphocyte subsets were measured in 1075 HIV-infected pregnant women in Tanzania at between 12 and 27 weeks' gestation. The results showed 49 (39%) more fetal deaths among those not on multivitamins compared with 30 among women assigned multivitamins. Multivitamin supplementation decreased the risk of low birthweight by 44%, severe preterm birth by 39%, and small size for gestational age at birth by 43%. Vitamin A supplementation had no significant effect on these particular variables. Multivitamins, but not vitamin A, resulted in a significant increase in CD4, CD8, and CD3 counts (immune system T-cells). Thus, multivitamin supplementation is a low-cost way of substantially decreasing adverse pregnancy outcomes and increasing T-cell counts in HIV-infected women.



  11. Foods, beverages and gastric cancer

    Full Source: International Journal of Epidemiology, 1998, Vol. 27, Iss 2, pp 173-180

    The daily intake of six beverages, cigarettes and alcohol and the weekly frequency of intake of 13 foods and food groups was estimated with a short food frequency questionnaire to 11 907 Japanese residents of Hawaii who were selected randomly. Over an average follow-up period of 14 years, 108 cases of gastric cancer (44 women, 64 men) were identified. The consumption of fresh fruit seven or more times per week was associated with a 40% reduced risk of gastric cancer, compared to lower levels of consumption. The more fresh fruit and raw vegetables consumed, the lower the risk of gastric cancer. No significant relationships were found between gastric cancer incidence and the intake of pickled vegetables, miso soup, dried or salted fish, or processed meats. Compared to non-drinkers, men who drank one cup of coffee per day had a significantly elevated risk of gastric cancer 97.5%. Cigarette smoking and consumption of alcohol were not related to gastric cancer, in analyses restricted to the men. The results related to fruit and vegetable intake can be explained by the actions against nitrates/nitrites) effect of these foods. (Nitrates and nitrites are carcinogenic agents implicated in the development of gastric, brain and other cancers). However, the unexpected association between coffee consumption and gastric cancer is difficult to explain and may represent a chance finding. Vitamin C and green tea also have potent effects against these nitrates/nitrites.



  12. Inhibition of ultraviolet B damage by Genistein

    Full Source: Carcinogenesis, 1998, Vol. 19, Iss 4, pp 649-654

    In this study, UVB irradiation substantially increased detectable effects of cancer genes in mouse skin. Topical application of Genistein 60 minutes before UVB radiation reduced these effects. Inhibition was stronger in skin exposed to the low dose than to the high dose of UVB radiation. Applying Genistein after UVB exposure reduced the effects to a lesser extent compared with pre-application. The results on human skin cancer cells showed that Genistein exhibited similar effects. Suppression of UVB-induced cancer gene expression in mouse skin suggests that Genistein may serve as a potential preventative agent against photo damage and photo-carcinogenesis.



  13. Use of percentage Free PSA in prostate cancer detection

    Full Source: Journal of the American Medical Association, 1998, Vol. 279, Iss 19, pp 1542-1547

    The percentage of free prostate-specific antigen (PSA) in serum has been shown to enhance the accuracy of PSA testing for prostate cancer detection. The percentage of free PSA may be used in 2 ways: 1) perform a biopsy for all patients at or below a cutoff of 25% free PSA, or 2) base biopsy decisions on each patient's risk of cancer. This study looked at a total of 773 men (379 with prostate cancer, 394 with benign prostatic disease) 50 to 75 years of age with a PSA level of 4.0 to 10.0 Ng/ml. Group 1 detected 95% of cancers while avoiding 20% of unnecessary biopsies. The cancers associated with greater than 25% free PSA were more prevalent in older patients, and generally were less threatening in terms of tumor grade and volume. For group 2, a lower percentage of free PSA was associated with a higher risk of cancer (8-56%). The percentage of free PSA was an independent predictor of prostate cancer and contributed significantly more than age or total PSA level. Use of the percentage of free PSA can reduce unnecessary biopsies in patients undergoing evaluation for prostate cancer, with a minimal loss in sensitivity in detecting cancer. A cutoff of 25% or less free PSA is recommended for patients with PSA values between 4.0 and 10.0 Ng/ml and a palpably benign gland, regardless of patient age or prostate size. This study is the largest series to date evaluating the percentage of free PSA in a population representative of patients in whom the test would be used in clinical practice.



  14. Deprenyl protects against brain cell death

    Full Source: Journal of Neurochemistry, 1998, Vol. 70, Iss 6, pp 2510-2515

    In Parkinson's disease, the cell death of dopamine neurons has been proposed to be mediated by an apoptotic (programmed) death process, in which nitric oxide may be involved. This study showed that deprenyl protected the cells from the DNA damage induced by nitric oxide or peroxy nitrite almost completely. The protection by deprenyl was significant even after it was washed from the cells, indicating that deprenyl may activate the intracellular system against apoptosis. These results suggest that deprenyl or related compounds may be neuroprotective to dopamine neurons through its anti-apoptotic activity.



  15. Aspirin cuts death rate among diabetics

    Full Source: The American Journal of Medicine 1998;105:494-499

    According to researchers in Israel, aspirin significantly cut the death rate from cardiac disease and other causes among 2,368 non-insulin-dependent diabetic patients who had coronary artery disease. The benefit of aspirin was greater in diabetic patients than in those without diabetes (8,586).

    Among the 10,954 patients, 52% of the diabetic patients and 56% of nondiabetic patients reported taking aspirin to reduce their heart risk. Both cardiac and other causes of mortality were substantially less common among diabetic patients taking aspirin in comparison to those not treated with aspirin. Among diabetics, the aspirin users had a 10.9% mortality risk from cardiac diseases while the nonusers had a 15.9% risk. Diabetics who took aspirin had an 18.4% risk of mortality from all causes compared with 26.2% for diabetics who did not take aspirin. Among nondiabetic patients, the mortality risk from cardiac diseases among aspirin users was also lower (4.8%) compared with that in those not taking aspirin (6.9%). They concluded that it is essential for all diabetic patients with coronary artery disease to be prescribed aspirin therapy unless there is a contraindication present.



  16. Cranberry extract inhibits LDL oxidation

    Full Source: Life Sciences, 1998, Vol. 62, Iss 24, pp PL381-PL386

    Cranberry juice consumption is often used for the treatment of urinary tract infections. When low density lipoprotein (LDL) oxidation took place in the presence of diluted cranberry extracts, the formation of thiobarbituric acid reactive substances (TBARS) and LDL electrophoretic mobility were reduced. LDL electrophoresis is the movement of particles in an electric field used to separate and purify biomolecules. This study suggests that cranberry extracts have the ability to inhibit the oxidative modification of LDL particles.



  17. Curcumin inhibits free radical generation in leukocytes

    Full Source: Japanese Journal of Cancer Research, 1998, Vol. 89, Iss 4, pp 361-370

    Curcumin exhibited significant inhibitory effects on free radical generation and intracellular peroxide formation in immune system cells treated with TPA (free radical generator). The inhibitory effects of curcumin on hydrogen peroxide (H2O2) formation in female mouse skin were further examined. Each TPA application induces 2 distinct biochemical events, 1) recruitment of inflammatory cells to the inflammatory regions, and 2) activation of oxidant-producing cells. Double pretreatment of mice with curcumin before each TPA treatment significantly suppressed H2O2 formation in the mouse skin. Thus, curcumin significantly suppress TPA-induced oxidative stress via both interference with infiltration of leukocytes into the inflammatory regions and inhibition of their activation.



  18. Lycopene uptake and tissue disposition

    Experimental Biology and Medicine, 1998, Vol. 218, Iss 2, pp 109-114

    Clinical studies suggest that tomato consumption may reduce the risk of cancer. Lycopene, is the major carotenoid in tomatoes and, as a potent free radical scavenger, has been considered to be the biologically active agent responsible for the reduction of cancer risk associated with tomato consumption. However, little is known concerning lycopene absorption or biological activity. This study provided information regarding the uptake and tissue disposition of lycopene. Betatene (a carotenoid mixture extracted from tomatoes) was added to the diet of 344 rats for 10 weeks. The results showed that 55% of administered lycopene was excreted in the feces. Lycopene concentrations were highest in the liver. Physiologically significant levels were detected in prostate, lung, mammary gland, and serum. Other carotenoids present in Betatene (i.e., z-carotene and beta-carotene) were also absorbed and stored in the liver. These results indicate that lycopene is absorbed in both male and female rats in a dose-related manner and can be detected at nanogram levels in a variety of organs.



  19. Role of tomato products in disease prevention

    Full Source: Experimental Biology and Medicine, 1998, Vol. 218, Iss 2, pp 140-143

    During the last 30 years, research in the field of nutrition and chronic disease causation has led to exciting, significant progress in providing an understanding of specific risk factors and chemopreventive agents. The major health problems considered are cardiovascular diseases and the nutritionally linked cancers, including those in the stomach, colon, breast, prostate, ovary, and endometrium. The major elements considered were salt, type and amount of fat, and heterocyclic amines formed during cooking. Bran cereal fiber, as well as vegetables, fruits, and tea have been shown to inhibit the complex processes of initiation and development of these diseases. One aspect involved in initiation and development of both cardiovascular diseases and cancer are abnormal oxidative processes leading to the generation of free radicals. In part, the protective role of vegetables, fruits, and tea is to provide antioxidant vitamins and specific polyphenols that display a powerful inhibition in oxidative reactions. Populations with a regular intake of tomato products, such as in the Mediterranean region, have a lower incidence of these chronic diseases noted. This article looked at the varied mechanisms of action of tomato products in general, and one of the active principles, lycopene. Cooking is a factor in releasing the desirable antioxidants from tomatoes. Cooked tomato products allow absorption of the active principles and are preferable to the raw vegetable or juices derived from tomatoes. Optimally, absorption of lycopene, a highly fat-soluble chemical, is improved in the presence of a small, but essential amount of oil or fat. Research in the field of nutrition and health has shown that monounsaturated oils such as olive oil or canola oil are most desirable, since such oils do not increase the risk of atherosclerosis, coronary heart disease, or the nutritionally linked cancers.



  20. Vitamin D3 protects against kidney damage

    Full Source: Kidney International, 1998, Vol. 53, Iss 6, pp 1696-1705

    Vitamin D-3 has known antiproliferative properties and has also been shown to inhibit kidney growth. Growth of capillaries (glomeruli) in kidneys can lead to the development of glomerulosclerosis (deposits or scarring within the kidneys). Rats with partially removed kidneys were treated with both vitamin D3 and ethanol or vitamin D3 alone. Glomerular volume and glomerulosclerosis was significantly less in the group treated with vitamin D3 and ethanol vs. vitamin D3 treatment alone. Albuminuria (protein in urine) was significantly lower in vitamin D3 group than in ethanol treated group. Vitamin D-3 showed antiproliferative actions during the compensatory growth of kidney cells in response to partial kidney removal. This demonstrates that Vitamin D-3 reduces kidney cell proliferation and capillary growth as well as glomerulosclerosis and albuminuria, which are indicators of progressive glomerular damage.



  21. Nutritional status with Crohn disease

    Full Source: American Journal of Clinical Nutrition, 1998, Vol. 67, Iss 5, pp 919-926

    Malnutrition is an important complication in patients with Crohn disease (CD) which is an inflammatory condition of the intestine. Four measures of nutritional status in 32 patients and 32 healthy control subjects were assessed: 1)body composition, 2) dietary intake, 3) biochemical indexes of nutrition, and 4) and muscle strength. The results showed average daily intakes of fiber and phosphorus were significantly lower in CD patients than in control subjects. Serum concentrations of several nutrients (beta-carotene, vitamin C, vitamin E, selenium, and zinc) and activity of the enzyme glutathione peroxidase (the body's natural antioxidant defense) were also significantly lower in CD patients, as were antioxidant status and serum concentrations of magnesium and vitamin D. Percentage body fat and hamstring muscle strength were significantly lower in male CD patients than in control subjects. This study showed a variety of nutritional and functional deficiencies in patients with long-standing CD in remission, especially in male patients with a high lifetime prednisone dose.



  22. Phyto-oestrogens: Where are we now?

    Full Source: British Journal of Nutrition, 1998, Vol. 79, Iss 5, pp 393-406

    The human Western diet is relatively deficient in phyto-oestrogens compared with societies where large amounts of plant foods and legumes are eaten. Phyto-oestrogens exert biological effects characteristic of estrogenic hormones. Evidence is beginning to mount that they offer protection against a wide range of human conditions, including breast, bowel, prostate and other cancers, cardiovascular disease, brain function, alcohol abuse, osteoporosis and menopausal symptoms. The two main classes are 1) isoflavones and 2) lignans. The isoflavones are under intensive investigation due to their high levels in soybeans. Like the 'anti-oestrogen' Tamoxifen, these seem to have oestrogenic effects in human subjects in the cardiovascular system and bone. Isoflavones were previously only available from food, but are now found in supplements and drinks. Tablets may soon be available over the counter as 'natural' hormone-replacement therapy. Anti-oestrogenic effects are thought to be important in combating cancer. Genistein, the active substance in soy, induces wide-ranging anti-cancer effects independent of any hormone-related influence. There are few indications of harmful effects at present. In infants, the effects of high levels in soya milk formulas are uncertain. The second class, lignans, have been less investigated despite their known anti-oestrogenic effects and more widespread occurrence in foods. The investigation of the possible benef its of phyto-oestrogens is hampered by lack of analytical standards. Hence, there are inadequate methods for the measurement of low levels in most foods. This problem may prove to be a major dilemma for regulatory authorities, clinicians, and others wishing to advise the public on whether these compounds really do have the health benefits attributed to them.



  23. Dietary fat and advanced prostate cancer

    Full Source: Journal of Urology, 1998, Vol 159, Iss 4, pp 1271-1275

    A diet history questionnaire was administered to 384 patients 45 years old or older with prostate cancer, including 142 with advanced and 242 with local stages I and II disease. Cases in the highest quartile of saturated fat consumption had a statistically significant odds ratio. In addition, the relation increased proportionally and significantly with saturated fat intake. Inverse associations of borderline significance were observed between advanced cancer, and polyunsaturated fat and linoleic acid intake. A positive trend was observed for total animal fat intake, while a negative trend was noted for total vegetable fat intake. This study suggests an association between saturated fat consumption and prostate cancer progression. If other similar studies confirm these results, dietary fat intake modification may be a promising intervention to prevent prostate cancer progression.

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