Selenium, calcium channel blockers, and cancer risk--the Yin and Yang of apoptosis?

Immunomodulatory Effects of Premna tomentosa (L. Verbenaceae) Extract in J 779 Macrophage Cell Cultures Under Chromate (VI)-Induced Immunosuppression

OBJECTIVE

In the present study, the immunomodulatory effects of Premna tomentosa extract against chromate (VI)-induced toxicity was assessed in J 779 macrophage cell line.

DESIGN

The cells were analyzed for cytotoxicity, phagocytosis, oxidant burst, antioxidant status, and cell proliferation.

RESULT

Chromate treatment resulted in a significant increase in cytotoxicity and free radical production. Furthermore, there is a significant decrease in reduced glutathione (GSH) levels and glutathione peroxidase activity (GPx). There was an appreciable decrease in cell proliferation and phagocytosis by macrophages in the presence of chromate. However, pretreatment of the cells with P. tomentosa extract (500 microg concentration), 30 minutes prior to chromate (VI) treatment resulted in a significant inhibition of chromate-induced cytotoxicity and reactive oxygen species production. The extract also restored the antioxidant status, cell proliferation, and phagocytosis similar to that of control cells.

CONCLUSION

The results confirm the cytoprotective and immunomodulatory effects of the leaves of P. tomentosa and its possible usage in immunosuppressed conditions.

Joint effects of citrus peel use and black tea intake on the risk of squamous cell carcinoma of the skin

BACKGROUND

Differences in tea drinking habits and/or citrus peel use are likely to vary by populations and could contribute to the inconsistencies found between studies comparing their consumption and cancer risk.

METHODS

A population-based case-control study was used to evaluate the relationships between citrus peel use and black tea intake and squamous cell carcinoma (SCC) of the skin. Moreover, we assessed the independent and interactive effects of citrus peel and black tea in the development of SCC.

RESULTS

Hot and iced teas were consumed by 30.7% and 51.8% of the subjects, respectively. Peel consumption was reported by 34.5% of subjects. Controls were more likely than were cases to report citrus peel use (odds ratio (OR) = 0.67) and hot tea intake (OR = 0.79). After adjustment for hot and iced tea intake, the ORs associated with citrus peel use were 0.55 and 0.69, respectively, whereas the corresponding adjusted ORs for hot and iced tea intake after adjustment for citrus peel use were 0.87 and 1.22 respectively. Compared with those who did not consume hot black tea or citrus peel, the adjusted ORs associated with sole consumption of hot black tea or citrus peel were 0.60 and 0.30, respectively. Subjects who reported consumption of both hot black tea and citrus peel had a significant marked decrease (OR= 0.22; 95% CI = 0.10 - 0.51) risk of skin SCC.

CONCLUSION

These results indicate that both citrus peel use and strong (hot) black tea have independent potential protective effects in relation to skin SCC.

Digitoxin is a potential anticancer agent for several types of cancer

The ability of digitalis to block cell proliferation has been well established for some time. Recently, digitalis in non-toxic concentrations has been showed to induce apoptosis in different malignant cell lines. In light of the pivotal role of apoptosis in cancer development and progression and this new experimental finding concerning digitalis, it seems probable that the apoptosis-inducing capability is explained by mechanisms other than just Na+/K+ ATPase inhibition. In this article, features of the cardiac glycosides which make them interesting to evaluate further as potential anticancer drugs are discussed. Some new data concerning inhibition and apoptosis in three human glioblastoma cell lines by digitoxin are also presented.

High-dose biotin, an inducer of glucokinase expression, may synergize with chromium picolinate to enable a definitive nutritional therapy for type II diabetes

Glucokinase (GK), expressed in hepatocyte and pancreatic beta cells, has a central regulatory role in glucose metabolism. Efficient GK activity is required for normal glucose-stimulated insulin secretion, postprandial hepatic glucose uptake, and the appropriate suppression of hepatic glucose output and gluconeogenesis by elevated plasma glucose. Hepatic GK activity is subnormal in diabetes, and GK may also be decreased in the beta cells of type II diabetics. In supraphysiological concentrations, biotin promotes the transcription and translation of the GK gene in hepatocytes; this effect appears to be mediated by activation of soluble guanylate cyclase. More recent evidence indicates that biotin likewise increases GK activity in islet cells. On the other hand, high-dose biotin suppresses hepatocyte transcription of phosphoenolpyruvate carboxykinase, the rate-limiting enzyme for gluconeogenesis. Administration of high-dose biotin has improved glycemic control in several diabetic animals models, and a recent Japanese clinical study concludes that biotin (3 mg t.i.d. orally) can substantially lower fasting glucose in type II diabetics, without side-effects. The recently demonstrated utility of chromium picolinate in type II diabetes appears to reflect improved peripheral insulin sensitivity--a parameter which is unlikely to be directly influenced by biotin. Thus, the joint administration of supranutritional doses of biotin and chromium picolinate is likely to combat insulin resistance, improve beta-cell function, enhance postprandial glucose uptake by both liver and skeletal muscle, and inhibit excessive hepatic glucose production. Conceivably, this safe, convenient, nutritional regimen will constitute a definitive therapy for many type II diabetics, and may likewise be useful in the prevention and management of gestational diabetes. Biotin should also aid glycemic control in type I patients.