LE Magazine, February 2001 - Medical Updates

February 2001
Table Of Contents

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2. CLA reduces breast tumor metastasis

   Full source: CANCER LETTERS, 2000, Vol 150, Iss 1, pp 93-100

   Conjugated linoleic acid (CLA) can inhibit the initiation and incidence of breast tumors in rodents. A study showed that CLA, had a significant effect on the latency, metastasis, and number of breast tumors in mice fed 20% fat diets. When concentrations of dietary CLA increased, the volume of tumors in the lungs, as a result of metastasis, decreased proportionately. The tumors had significantly decreased numbers of pulmonary nodules when compared with diets containing no CLA. The decrease in the number of pulmonary nodules by CLA was nearly as effective as the drug, indomethacin, a known suppressor of tumor growth and metastasis in these malignant tumors. Thus, the effects of CLA on breast cancer growth may go beyond the reported alterations in tumor incidence and effect later stages, especially metastasis.

   
   
   

3. Genistein shows synergistic effects on prostate cancer cells

   Full source: CANCER LETTERS, 2000, Vol 151, Iss 1, pp 103-109
   
   Habitual consumption of green tea is associated with a reduction in cancers, including prostate. Soybean isoflavones are also associated with prevention. A study compared the anti-proliferative effect of black tea polyphenol, alone or combined with the isoflavone genistein, on human prostate cancer cells. The black tea polyphenol administered alone did not result in any alteration of cell growth. However, when combined with genistein, the black tea significantly inhibited cell growth and caused the cell cycle in the G2/M cell division phase to cease progressing. This indicates the potential use of combined phytochemicals to provide protection against prostate cancer.
   
   

   
   
   

4. Vitamin C, blood pressure, and heart disease in older persons

   Full source: JOURNAL OF HYPERTENSION, 2000, Vol 18, Iss 4, pp 411-415

   A study determined the effect of oral vitamin C supplements on ambulatory blood pressure. Vitamin C (500 mg daily or matching placebo) was given to 40 men and women aged between 60 and 80 years for 3 months. Daytime ambulatory blood pressure showed a significant fall in systolic blood pressure (2.0 mmHg; 95% confidence interval 0-3.9 mmHg) but not in diastolic blood pressure. With increasing beginning daytime blood pressure, the fall in blood pressure with vitamin C supplementation increased. In women, but not men, HDL cholesterol increased significantly by 0.08 mmol/l. Thus, in older adults, high intakes of vitamin C lower high systolic blood pressure, which could contribute to the reported association between higher vitamin C intake and lower risk of cardiovascular disease and stroke.

   
   
   

5. Melatonin and colon cancer

   Full source: EXPERIMENTAL AND TOXICOLOGIC PATHOLOGY, 2000, Vol 52, Iss 1, pp 71-76

   In rats with artificially stimulated tumor growth, colon tumors developed in 100% of the animals exposed both to a carcinogen alone, or to the carcinogen plus melatonin. However, only 65% of the animals exposed to the carcinogen plus melatonin developed colon cancer. The multiplicity of colon tumors was also reduced in rats under the influence of melatonin. The pineal hormone (production of melatonin) has an inhibitory effect on division and growth of cells. Melatonin has a stimulating effect on apoptosis (programmed cell death) in colon tumors. Long-term treatment with melatonin was followed also by the decrease in the area of lymphoid infiltrates in the mucous membrane of the colon of tumor-bearing animals.

   
   
   

6. COQ10 supplements make the heart resistant to ischemia-reperfusion injury

   Full source: AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY, 2000, Vol 278, Iss 4, pp H1084-H1090

   A study examined whether nutritional supplementation of coenzyme Q(10) (CoQ(10)) can reduce ischemia-reperfusion injury of the heart. One group of pigs was fed a regular diet supplemented with CoQ(10) and another group a regular diet supplemented with placebo served as a control for 30 days. The hearts were subjected to regional ischemia (deficiency of blood due to ischemia). The result showed contractile function of the left ventricle was better recovered in the CoQ(10) group. In addition, CoQ(10)-fed pigs revealed less heart attach and less creatine kinase release from the heart outflow. The COQ10 group also demonstrated a smaller amount of malonaldehyde (a marker of free radical stress) in the heart outflow and a higher content of the endogenous antioxidants ascorbate and thiol. In addition, there was significant ubiquitin mRNA activity caused in the hearts of the CoQ(10)-fed group. The results of the study demonstrate that nutritional supplementation of CoQ(10) renders the heart resistant to ischemia-reperfusion injury, probably by reducing free radical stress.

   
   
   

7. Effects of saw palmetto for benign prostatic hyperplasia

   Full source: JOURNAL OF UROLOGY, 2000, Vol 163, Iss 5, pp 1451-1456

   A study tested the effects of a saw palmetto herbal blend in 44 men (45 to 80 years) with symptomatic benign prostatic hyperplasia (BPH). Saw palmetto herbal blend and placebo groups had improved clinical parameters with a slight advantage in the saw palmetto group. Neither prostate specific antigen (PSA) nor prostate volume (PV) changed from starting point. Prostate epithelial contraction was noted, especially in the transition zone, where percent epithelium decreased from 17.8% at baseline to 10.7% after 6 months of saw palmetto herbal blend. Tissue studies showed that the percent of atrophic glands increased from 25.2% to 40.9% after treatment with saw palmetto herbal blend. The mechanism of action appeared to be nonhormonal. There were no adverse effects of saw palmetto herbal blend. Thus, saw palmetto herbal blend appears to be a safe, highly desirable option for men with moderately symptomatic BPH.
   
   

   
   

8. Effect of soy protein foods on LDL oxidation

   Full source: METABOLISM-CLINICAL AND EXPERIMENTAL, 2000, Vol 49, Iss 4, pp 537-543

   Plant-derived estrogen analogs (phytoestrogens) may offer significant health advantages including cholesterol reduction, antioxidant activity, and possibly a reduced cancer risk. However, the concern has also been raised that phytoestrogens may be disrupt endocrine activities. A study assessed the effects of soy foods as a rich source of isoflavonoid phytoestrogens on LDL oxidation and sex hormone receptor activity on 31 individuals with high levels of lipids in the blood. There were two 1-month low-fat metabolic diets in the study. The major differences between the test and control diets were an increase in soy protein foods (33 g/day soy protein) providing 86 mg isoflavones/2,000 kcal/day and a doubling of the soluble fiber intake. The results of the test diet showed that consumption of high-isoflavone foods was associated with reduced levels of circulating oxidized LDL (56 vs. 63 mu mol/L.), even in those already using vitamin E supplements (400 to 800 mg/day), with no evidence of increased urinary estrogenic activity. Therefore, soy consumption may reduce cardiovascular disease risk without increasing the risk for hormone-dependent cancers.

   
   

9. Effect of vitamin C supplementation on immune response

   Full source: VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY, 2000, Vol 74, Iss 1-2, pp 145-152

   A study divided chickens into two groups. One group was fed a diet supplemented with 1000 ppm vitamin C and the other group was fed an identical diet, but not supplemented with vitamin C. Both groups were vaccinated against infectious bursal disease (IBD) at 7 days of age and then given a lethal-dose IBDV 14 days later. The results showed that the number of CD8(+) cells in spleen and IgM(+) cells at 7, 21 and 31 days of age were significantly higher in vitamin C supplemented group. The production of interleukin-2 (hormonal-like substance which stimulates immune system) by splenocytes (lymphocytes, that fight infection and disease) was higher in the vitamin C supplemented group. The number of antibody secreting cells in spleen at 21 and 31 days of age were significantly higher in the vitamin C supplemented group. Thus, the dietary supplementation of vitamin C may improve the suppression of the immune system caused by vaccinations and improve humoral and cellular immune responses.

   
   

10. Vitamin D-3 inhibits liver cancer

    Full source: CANCER LETTERS, 2000, Vol 151, Iss 1, pp 97-102

    A study looked at the effect of vitamin D-3 on the proliferation of a number of types of human and rat liver cancer cells, as well as the rate of growth of liver cancer cell grafts in mice. Vitamin D-3 significantly inhibited the proliferation of three different cell types, while two were more resistant to the inhibitory effects of the vitamin. Thus, the treatment of tumor bearing mice with different doses of vitamin D-3 significantly retarded tumor growth without the development of hypercalcemia (excess of calcium in the blood).
    
    

    
    

11. Role of telomerase in cell aging and cancer

    Full source: ANNUAL REVIEW OF MEDICINE, 2000, Vol 51, pp 65-79

    The ends of chromosomes are capped by specialized structures called telomeres. Telomeres are metabolic precursors of nucleic acids that, in combination with specific proteins, protect against degradation, rearrangement, and fusion of chromosomes, preventing reunion with any fragment after a chromosome has been broken. Telomeres are reported to be a central mechanism in cell aging. There is a net loss of telomeric sequences that occurs at each cell division. It has been proposed that this cumulative telomeric erosion limits replicative capacity of chromosomes, and sends a signal for the start of cellular aging. To proliferate beyond this "checkpoint" of aging, cells must restore telomere length. This can be achieved by telomerase, an enzyme with reverse-transcriptase activity. Ironically, this enzyme is absent in normal tissues, but telomerase reactivation has been detected in most tumors. Investigative effort is focusing on telomere dynamics with a view to possible manipulation of cellular proliferative potential. The potential exists for the use of telomerase in diagnosis and treatment of tumors.

    
    

12. Grape seed extract fights tumors

    Full source: ANTICANCER RESEARCH, 2000, Vol 20, Iss 1A, pp 423-426

    Grape seed extracts were more toxic to cancer cells than grape peel extracts. 70% extracts of grape seed selectively killed two human oral tumor cell lines, more efficiently than human gingival (mucous membranes) cells. A test of inflammation revealed that these extracts produced radicals under alkaline conditions and enhanced the radical intensity of vitamin C at higher concentrations. On the other hand, lower concentration of these extracts slightly reduced the radical intensity of vitamin C and scavenged superoxide anion free radical. These properties of grape seen extracts suggest their possible application for cancer prevention.
    
    

    
    

13. Resveratrol in grapes decreases PSA

    Full source: ANTICANCER RESEARCH, 2000, Vol 20, Iss 1A, pp 225-228

    Resveratrol is a polyphenol present in red wines and various human foods. It inhibited the proliferation of prostate cancer cells and the activity of a prostate specific gene, PSA. A 4-day treatment with resveratrol reduced the levels of intracellular and secreted PSA by approximately 80%, as compared to controls. This decrease was tested to determine whether this decrease was coordinated with changes in activity of androgen receptor (AR, male hormone). Little or no change in AR expression could be detected between control and resveratrol-treated cells. Thus, it would appear that the activity of prostate tumor marker PSA is lessened by resveratrol, by a mechanism separate from changes in AR.

    
    

14. Excess mortality associated with increased pulse pressure

    Full source: JOURNAL OF HYPERTENSION, 2000, Vol 18, Iss 4, pp 417-423

    A 15 year follow-up study of 9,603 men and women assessed the risk of death from coronary heart disease, stroke, all cardiovascular diseases and all-cause mortality associated with pulse pressure among the middle-aged population (45-64 years). Each survey included a self-administered questionnaire with questions on smoking and antihypertensive drug treatment, measurements of height, weight and blood pressure and the determination of the serum cholesterol concentration. The risk of coronary heart disease, stroke, cardiovascular disease and all-cause mortality increased with the increasing pulse pressure, independent of the diastolic blood pressure level. Only in women with diastolic blood pressure greater than or equal to 95 mmHg was the risk of fatal stroke not statistically significant. After adjustment for systolic blood pressure, the positive association between mortality and increasing pulse pressure disappeared. Thus, increasing pulse pressure is a predictor of death from coronary heart disease, stroke, cardiovascular disease and all causes in men and women aged 45-64 years, but the increase in risk is entirely associated with the increase in systolic blood pressure.

    
    

15. Inhibitory effects of carotenoids on liver cancer cells

    Full source: CANCER LETTERS, 2000, Vol 151, Iss 1, pp 111-115

    The effects of carotenoids - alpha-carotene, beta-carotene, lycopene, beta-cryptoxanthin, zeaxanthin, lutein, canthaxanthin, astaxanthin - on the invasion from rat liver tumor cells were investigated. All the carotenoids examined inhibited the invasion in a dose-dependent manner. Cancer cells previously cultured with hypoxanthine (HX) and xanthine oxidase (XO) showed a highly invasive activity. However, the carotenoids, 5 mu M of beta-carotene and astaxanthin, suppressed this free radical invasive capacity. The results suggest that the anti-invasive action toward the tumors be a result of the antioxidant properties of these carotenoids.
    
    

    
    

16. Effect of curcumin on bone marrow

    Full source: ENVIRONMENTAL MUTAGENESIS, 2000, Vol 465, Iss 1-2, pp 131-137

    Dietary antioxidants are showing evidence of preventing chromosomal damage in non-tumor cells, which is induced by anti-tumor drugs. Curcumin is a dietary antioxidant that has been reported to protect against disruption or breakages in chromosomes. A study investigated the effects of curcumin on chromosomal aberrations in rat bone marrow cells and whether there is any enhancement of these effects with the combination of curcumin and vitamin C. Animals treated with curcumin plus a single dose of cisplatin (an anti-tumor drug), between 18-72 hours after the drug. The results showed a significant reduction in the total amount of chromosomal damage and in the number of abnormal metaphases (2nd stage of cell division). Thus, curcumin could prevent damage to chromosomes, caused by a tumor suppressor drug, by acting as a free radical scavenger.