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LE Magazine February 2000

MEDICAL UPDATES
Studies from throughout the world that can help you live longer

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February 2000
Table Of Contents

  1. Effect of dietary lycopene on abnormal growth in the colon
  2. Vitamin D-3 blood levels and Colorectal cancer
  3. Effects of Ginkgo biloba extract on memory
  4. Protective effects of Biostim, a bacterial immunomodulator
  5. Tocotrienol: A review of its therapeutic potential
  6. Effects of ginkgo biloba on depression
  7. DHEA dose and serum levels
  8. Zinc protects against ultraviolet-induced DNA damage
  9. Lifetime exercise activity and breast cancer risk
  10. The effects of Chlorella on natural killer cells


  1. Effect of dietary lycopene on abnormal growth in the colon

    Full source: Nutrition Research, 1999, Vol 19, Iss 9, pp 1383-1391

    Studies have suggested a protective role for lycopene, an antioxidant carotenoid, in the prevention of chronic diseases including cancer and coronary heart disease. Tomatoes and tomato products are the major dietary source of lycopene. This study investigated the bioavailability, tissue distribution, and the antioxidant properties of lycopene and its role in colon cancer. Lycopene was incorporated into a rat diet and a colon carcinogen was administered. Blood and tissue lycopene levels were measured as estimates of lycopene uptake and tissue distribution. Blood TBARS and thiols were measured as indicators of lipid and protein oxidation. Incidence and size of aberrant crypt foci (ACF) (atypical cells) were measured as pre-cancerous markers. Results showed an increase in blood thiols and a decrease in serum TBARS in rats fed the lycopene diet. Incidence of ACF in lycopene fed rats showed a trend towards reduced numbers and size. The beneficial effects were more pronounced when lycopene was fed during the cell growth promotion stage than during the cell initiation stage. Based on these results it is concluded that dietary lycopene is absorbed by rats and distributed to various tissues. It acts as an antioxidant in reducing oxidation and thereby may protect against chemically induced ACF incidence. Lycopene may play an important role in protecting against free radical damage and colon cancer.



  2. Vitamin D-3 blood levels and Colorectal cancer

    Full source: Cancer, 1999, Vol 86, Iss 3, pp 391-397

    Studies have demonstrated an opposite relationship between dietary calcium plus vitamin D intake and the incidence of cancer of the colon and rectum. Elevated blood levels of vitamin D-3 are associated with a major reduction in the incidence of these tumors. Calcium supplements normally reduce tumor size and number, but this beneficial action was neutralized by a vitamin D-3 deficiency. Vitamin D blood levels have not been determined previously in colorectal cancer patients. This study compared serum vitamin D-3, and parathyroid hormone (PTH) levels of 84 colorectal carcinoma patients (10 with Stage I, 29 with Stage II, 25 with Stage III, and 20 With Stage IV) and 30 healthy controls, all of whom were normocalcemic and not taking calcium or vitamin D supplements. Results showed blood vitamin D-3, and PTH levels higher in cancer patients than controls, irrespective of stage. Blood vitamin D-3 decreased with advancing stage of cancer: 73, 48, 39, 34, and 75 pg/mL in Stages I, II, III, IV and controls, respectively. There was a corresponding increase in blood PTH levels: 58.0, 73.7, 79.0, 100.4, and 51.2 pg/mL in Stages I, II, III, TV, and controls, respectively. Blood vitamin D metabolite levels did not correlate with gender, age, tumor localization, or histologic grade. Thus, an opposite relationship between blood levels of the active metabolite of vitamin D and colorectal cancer stage has been demonstrated for the first time, in colorectal cancer patients. Because vitamin D-3 has been shown to inhibit proliferation of colon cells, having decreased blood levels of vitamin D-3 may facilitate the growth of colon and rectal cancer and influence its biologic behavior.



  3. Effects of Ginkgo biloba extract on memory

    Full source: Phytotherapy Research, 1999, Vol 13, Iss 5, pp 408-415

    Thirty-one volunteers aged 30-59 years received Ginkgo biloba extract (GBE) 120 mg, 150 mg, and 300 mg, and placebo for 2 days. Following baseline measures, the medication was administered at 9am for the single doses and at 9, 12 and 9pm for the multiple doses. The testing and measuring of mental and psychologic ability, efficiency, potentials, and functioning was administered pre-dose (08:30am) and then at frequent intervals until 11am post dose. The results confirm that the effects of GBE extract on aspects of cognition in asymptomatic volunteers are more pronounced for memory, particularly working memory. They also show that these effects may be dose dependent though not in a linear dose related manner, and that GBE 120 mg produces the most evident effects of the doses examined. Additionally, the results suggest that the cognitive enhancing effects of GBE are more likely to be apparent in individuals aged 50-59 years.



  4. Protective effects of Biostim, a bacterial immunomodulator

    Full source: International Journal of Immunopharmacology, 1999, Vol 21, Iss 9, pp 561-574

    Biostim is an immunomodulator extracted from Klebsiella pneumoniae (a bacterium which causes pneumonia and other respiratory infections). In humans, it is able to reduce the duration and severity of chronic bronchitis. In this study, oral Biostim strongly protected against bacterial infections by preventing lethal septicemia (infection of the blood), and, to a lesser extent, protected against the intracellular pathogen Listeria Monocytogenes. Administration of Biostim leads to the mobilization of newly dividing T and B immune cells in the thoracic duct lymph. This reflects the ability of the drug, to induce an immune response in gut-associated lymph tissue. In cells isolated from lymph nodes and spleen, Biostim leads to a release of the proinflammatory cytokines interleukin (IL)-12 and/or interferon (IFN)-gamma, as well as IL-IO, a cytokine involved in inhibiting the synthesis of these latter cytokines. Biostim also increases the serum total immunoglobulin IgM concentration and elicits IgM and IgG antibodies against the drug. Infection of mice with Klebsiella pneumoniae has similar functional consequences. Thus, pretreatment with Biostim of infected mice, leads to a fall in the high levels of proinflammatory cytokines (high levels could be detrimental), and to an increase in IgG antibodies (which are protective). (The FDA does not allow Biostin to be imported into the U.S., even though Europeans have safely used it for decades.)



  5. Tocotrienol: A review of its therapeutic potential

    Full source: Clinical Biochemistry, 1999, Vol 32, Iss 5, pp 309-319

    Tocotrienol is a natural analogue of tocopherol (vitamin E). The biological activity of vitamin E has generally been associated with its well-defined antioxidant property, specifically against lipid peroxidation in biological membranes. In the vitamin E group, alpha-tocopherol has been considered the most active form. However, recent research has suggested tocotrienol to be a better antioxidant. In addition, tocotrienol has been shown to possess novel hypocholesterolemic (cholesterol-lowering) effects together with an ability to reduce the atherogenic apolipoprotein B and lipoprotein (a) blood levels. In addition, tocotrienol has been suggested to have an anti-clotting and anti-tumor effect indicating that tocotrienol may serve as an effective agent in the prevention and/or treatment of cardiovascular disease and cancer. The physiological activities of tocotrienol suggest it to be superior to vitamin E in many situations. The role of tocotrienol in the prevention of cardiovascular disease and cancer may have significant clinical implications.



  6. Effects of ginkgo biloba on depression

    Full source: General Pharmacology, 1999, Vol 33, Iss 3, pp 249-256

    This study examined the effects of Ginkgo biloba on depression of the central nervous system (CNS). Ginkgo, given 60 minutes prior to sodium barbital, significantly shortened barbital-induced sleeping time and the effects were reflected as increases in time period leading up to sleep and with decreases in the number of mice that slept. At the behavioral level, these potent bodily effects of Ginkgo resemble those of certain antidepressants. At the molecular level, it is hypothesized that interactions with channels of the CNS may be involved. This may explain the clinically observed "vigilance-enhancing" and "antidepressant-like" actions of Ginkgo biloba.



  7. DHEA dose and serum levels

    Full source: Clinical Biochemistry, 1999, Vol 32, Iss 5, pp 355-361

    Studies from both experimental animals and humans suggest that administration of DHEA may have beneficial endocrine-metabolic, immunologic and neurologic effects. Several groups have administered DHEA to humans, but no one at this point has published a summary of the relationship between the administered dose of DHEA and the serum levels of steroids attained. The full article summarizes the relationship between the administered dose of DHEA and the resulting serum level of DHEA and DHEA-S, in humans, from 18 published articles. It shows that serum levels of DHEA and DHEA-S increase with increasing doses. Doses above 50 mg/day result in levels that are at or above the upper limit of normal for healthy young adults. At doses above 300 mg/day, the increment of serum DHEA and DHEA-S appears to reach a plateau. Those wanting to use supplemental DHEA might consider that doses of 300 mg/day are maximal; they clearly result in supraphysiologic concentrations (denotes a dose that is larger or more potent than would occur naturally) and above this level doses may have increased side effects without significantly increasing the effective level of serum hormone. (Editor's note: Life Extension recommends doses of 15 to 75 mg a day of DHEA.)



  8. Zinc protects against ultraviolet-induced DNA damage

    Full source: Biological Trace Element Research, 1999, Vol 69, Iss 3, pp 177-190

    Ultraviolet (UVA) radiation generates free radicals, and this oxidative stress is known as a mediator of DNA damage and of apoptosis (cell death). Human skin cells were exposed to UVA radiation and showed an immediate significant increase of DNA strand breaks in exposed cells. UVA radiation induced an early (8 hour) and a delayed (18 hour) apoptosis. Delayed apoptosis increased in a UVA dose-dependent manner. Zinc is an important metal for DNA protection and has been shown to have inhibitory effects on apoptosis. The addition of zinc (6.5 mg/L) as zinc chloride to the culture medium significantly decreased immediate DNA strand breaks in human skin cells. In addition, zinc chloride significantly decreased UVA1-induced early and delayed apoptosis. This data shows for the first time in normal cultured skin cells that UVA1 radiation induces apoptosis. This apoptosis appears higher 18 hours after the stress. Zinc supplementation can prevent both immediate DNA strand breakage and early and delayed apoptosis. Thus, this suggests that zinc could be of interest for skin cell protection against UVA1 irradiation.



  9. Lifetime exercise activity and breast cancer risk

    Full source: British Journal of Cancer, 1999, Vol 80, Iss 11, pp 1852-1858

    Lifetime exercise activity has been linked to breast cancer risk among young women. However, no study has specifically evaluated its relation to breast cancer risk of post-menopausal women. This study looked at post-menopausal white women (1123 newly diagnosed cases and 904 healthy controls) aged 55-64 who lived in Los Angeles County, California, USA. Although neither exercise activity from the age of menarche (establishment of the menstrual function) to age 40 years, nor exercise after age 40 separately predicted breast cancer risk, the risk was lower among women who had exercised each week for at least 17.6 MET-hours (metabolic equivalent of energy expenditure multiplied by hours of activity) since menarche than among inactive women. However, exercise activity was not protective for women who gained considerable (over 17%) weight during adulthood. Among women with more stable weight, breast cancer risk was substantially reduced for: 1) those who consistently exercised at high levels throughout their lifetime, 2) those who exercised more than 4 hours per week for at least 12 years, and 3) those who exercised vigorously (24.5 MET-hours per week) during the most recent 10 years. Thus, strenuous exercise appears to reduce breast cancer risk among post-menopausal women who do not gain sizable amounts of weight during adulthood.



  10. The effects of Chlorella on natural killer cells

    Full source: Immunopharmacology and Immunotoxicology, 1999, Vol 21, Iss 3, pp 609-619

    This study demonstrated the effects of oral administration of Chlorella vulgaris (CV) on Natural Killer cells (NK) activity of mice infected with Listeria monocytogenes (bacteria that produce upper respiratory disease, septicemia (blood poison), and encephalitic disease). Results showed that Chlorellaproduced a significant increase on NK cells activity in normal (non-infected) animals compared to the animals that received only water. Similarly, the Listeria infection alone produced a significant increase on NK cells activity, which was observed at 48 and 72 hours after the inoculation of Listeria. However, when CV was administered in infected animals, there was an additional increase in NK cells activity which was significantly higher than that found in the infected groups. Finally, CV treatment of mice infected with a lethal dose for all the non-treated controls, produced a dose-response protection which led to a 20% and 55% survival, respectively.




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