A three-year study has been conducted for prevention of infectious hepatitis with supplementation of table salt fortified with 15 ppm anhydrous sodium selenite to the general population of 20,847 persons in a township M.Z. at Qidong County, Jiangsu Province, China. The results showed that the incidence of virus hepatitis infection in the test township was significantly lower than that of controls provided with normal table salt. The incidence rate of infectious hepatitis in the treated township M.Z. was 1.20 and 4.52 per 1,000, whereas the average incidence in the 6 surrounding control townships was 2.96 and 10.48 per 1,000 in 1986 and 1987, respectively. The incidence of hepatitis B surface antigen (HBsAg+) was 13.2% vs 19.23% for males and 10.42% vs 12.24% for females in the supplemented vs nonsupplemented neighboring township, respectively. Epidemiological studies have demonstrated that a low grain Se content is associated with a high regional incidence of hepatitis B virus infections.

Adult↗

PubMedDate not supplied

Selenium chemoprevention of liver cancer in animals and possible human applications.

An inverse correlation between geographic distribution of liver cancer incidence and the selenium (Se) contents of whole blood and grains was observed in Qidong county, Jiangsu province, a high liver cancer area of the People's Republic of China. Animal experiments demonstrated that supplementation of Se reduced the incidence of liver cancer in rats exposed to aflatoxin B1. Se was also shown to inhibit the growth of transplanted tumors. A lower incidence of liver preneoplastic alterations and reduction of hepatitis B virus infection in ducks by Se-supplementation was observed, and three pilot studies for a Se-intervention trial on human liver cancer were carried out on the residents of Qidong county. A protective effect on the cellular DNA damage induced by aflatoxin B1 was observed in lympocytes from human with Se-supplements.

Aflatoxins↗

PubMedDate not supplied

Biochemical and cellular aspects of the anticancer activity of selenium.

Aberrant differentiation is a frequent hallmark of tumors, suggesting that modulators for differentiation and proliferation play a role in multistage carcinogenesis and that their use can also be exploited in cancer chemoprevention and therapy. We have demonstrated that selenium (Se) may be a modulator for the differentiation and proliferation of tumor cells. Evidence has been obtained that Se exerts the following effects: reversing changes of biochemical phenotypes toward normal levels, including reduction of cGMP level and cAMP-dependent protein kinase isozyme type I; increase in cAMP level and cAMP-dependent protein kinase isozyme type II, and altering membrane properties. Furthermore, we have obtained support for this hypothesis utilizing experiments on cultured human liver cell lines. It is demonstrated that Se can lead to the following changes: a. reduction of mitotic index; b. increase in the adhesiveness of cells; c. decrease in confluent saturation density and induction of an early contact inhibition; and d. decrease in tumorigenicity. For the purpose of comparison, the effects of Se on the normal counterparts was also studied. Contrary to what was observed above, there was no significant change in both biochemical and cellular aspects of normal cells treated analogously.

Animals↗

PubMedDate not supplied

Comparative direct-acting mutagenicity of 1- and 2-nitropyrene: evidence for 2-nitropyrene mutagenesis by both guanine and adenine adducts.

The mutations and DNA adducts produced by the environmental pollutant 2-nitropyrene were examined in Salmonella typhimurium tester strains. 2-Nitropyrene was a stronger mutagen than its extensively studied structural isomer 1-nitropyrene in strains TA96, TA97, TA98, TA100, TA102, TA104 and TA1538. Both 1- and 2-nitropyrene were essentially inactive in TA1535. The mutagenicity of 1- and 2-nitropyrene in TA98 was much higher than in TA98NR and the activity of these compounds in TA100 was much higher than in TA100NR. While 1-nitropyrene exhibited similar mutagenicity in strains TA98 and TA98/1,8-DNP6, the mutagenicity of 2-nitropyrene in TA98/1,8-DNP6 was much lower than in TA98. Analysis of DNA from TA96 and TA104 incubated with 2-nitropyrene indicated the presence of two adducts, N-(deoxyguanosin-8-yl)-2-aminopyrene and N-(deoxyadenosin-8-yl)-2-aminopyrene. The results suggest that 2-nitropyrene is metabolized by bacterial nitroreductase(s) to N-hydroxy-2-aminopyrene, and possibly by activation to a highly mutagenic O-acetoxy ester. DNA adduct formation with deoxyguanosine and deoxyadenosine correlates with the mutagenicity of 2-nitropyrene in tester strains possessing both G:C and A:T mutational targets.

Adenine↗