1-p-D-Arabinofuranosylthymine (ara-T), a metabolite of the sponge Tethya crypta, has shown selective activity against herpes simplex virus (HSV) replication (G. A. Gentry and J. F. Aswell, Virology 65:294-296, 1975 responsible for the selective antiviral activity of ara-T. This conclusion was further supported by experiments that showed that the replication ofa variety of dPyK-mutants of HSV-1 and HSV-2 were not affected by ara-T and that ara-T inhibited the phosphorylation of deoxycytidine and deoxythymidine by HSV-1 dPyK, but not by host deoxycytidine and deoxythymidine kinases, respectively. Ara-T also selectively inhibited the replication ofequine herpesvirus type 1 (EHV-1) in vitro and was effective against EHV-1 infection in vivo in hamsters. Further, EHV-1 was inhibited by ara-T and by bromodeoxyuridine in LM cells lacking a cytosol thymidine kinase, suggesting that EHV-1 induces a dPyK. Finally, spectrophotometric assay for thymine suggested that ara-T is not a substrate for nucleoside phosphorylase of hamster liver, and a microbiological assay indicated that substantial amounts of ara-T were excreted in the urine of uninfected hamsters that had received a single injection of 5 mg of ara-T, the amount given in each injection in the in vivo experiments with EHV-1.1-p-D-Arabinofuranosylthymine (ara-T; spongothymidine) was first isolated, rather by coincidence, by Bergmann and Feeney (5) in a study of the sterol content (4) of Tethya crypta, a sponge first described as growing almost buried in the ocean floor off the Bahamas (16). Subsequently, ara-T was found to have little effect on the multiplication of tumor cells in culture (11,15) but was later shown to be somewhat inhibitory to herpesvirus replication in vivo (17,18,53,54,56). The demonstration (26) that herpes simplex virus (HSV)-infected cells contain a pyrimidine deoxyribonucleoside kinase (dPyK) with a broad substrate specificity (29,30) suggested that ara-T might be phospho- showing that ara-T at 2 x 10-M completely blocked the replication of HSV type 1 (HSV-1) and HSV type 2 (HSV-2) in BHK cells but had no measurable effect on the multiplication of uninfected BHK cells subcultured at low cell density and followed for several generations (23). It has subsequently been shown that several other deoythymidine (dT) analogs have similar selectivity against HSV, including 5'-amino-2',5'-dideoxy-5-iodouridine, 5-ethyldeoxyuridine, 5-propyldeoxyuridine, 5-allyldeoxyuridine (8, 10); 5-bromodeoxycytidine, 5-iododeoxycytidine (13,20, 24,31); and 5-methoxymethyldeoxyuridine (2,3). This suggests that the HSV-specified dPyK may be a useful tool in

Levels of selenium in whole blood, plasma, erythrocytes and platelets, glutathione peroxidase (EC 1.11.1.9; GSH-Px) activity in erythrocytes and platelets and vitamin E, low-density-lipoprotein (LDL)-cholesterol and vitamin E: LDL cholesterol in plasma were measured in seventy-five healthy subjects aged < 65 years and twenty-eight healthy and twenty-three institutionalized elderly people aged > 65 years. Healthy elderly subjects had significantly lower levels of Se in whole blood and plasma when compared with younger subjects. Other measurements of Se status were not significantly different. In the healthy subjects plasma levels of vitamin E and LDL-cholesterol increased with age to 60 years and decreased above 80 years. Vitamin E: LDL cholesterol values were not affected by age. Measurements of Se and vitamin E status in the institutionalized elderly compared with the healthy elderly were all reduced with the exception of platelet Se levels and erythrocyte GSH-Px activity. Ageing per se had minimal effect on Se and vitamin E status but intercnrrent illness and decreased food intake can lead to reduced levels in the elderly. Selenium: Vitamin E: Old age.