Selenium, a metalloid mineral micronutrient,is an essential component for the adequate and healthy life of human, animals, and some other microorganisms.Selenium has antioxidative and oxidative effects on living organisms.Selenium deficiency has been associated with impaired function of the immune system.Selenium deficiency appears to enhance the virulence or progression of some viral infections.Selenium deficiency results in decreased activity of glutathione peroxidase, increasing oxidative damage and the likelihood of mutations in the viral genome.The safe range of selenium intake is relatively small and excess selenium intake can readily result in toxicity.This review summarizes the updates of benefitial and adverse effects of selenium on health.

Objectives To evaluate the value of detecting p53 gene point mutations in sputum samples and its validity and reliability as a surveillance index in the early diagnosis of lung cancer in suspicious patients.Methods Sputum samples were collected from 54 cases identified as lung cancer and 114 cases identified as pulmonary benign disease. The polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) was performed for the detection of point mutations at exons 5-8 of the p53 gene, and sputum smears were also used for each sample. Conclusion Detection of p53 gene alterations in sputum samples by PCR-SSCP-silver stain can be used as a follow-up surveillance index for the early diagnosis of lung cancer in suspicious patients.