Biomedical subjects

Gregory E Glass

Publications and source records attributed to Gregory E Glass.

21 records · Page 2Linked to original sources

PubMed2002

Satellite imagery characterizes local animal reservoir populations of Sin Nombre virus in the southwestern United States.

The relationship between the risk of hantaviral pulmonary syndrome (HPS), as estimated from satellite imagery, and local rodent populations was examined. HPS risk, predicted before rodent sampling, was highly associated with the abundance of Peromyscus maniculatus, the reservoir of Sin Nombre virus (SNV). P. maniculatus were common in high-risk sites, and populations in high-risk areas were skewed toward adult males, the subclass most frequently infected with SNV. In the year after an El Niño Southern Oscillation (ENSO), captures of P. maniculatus increased only in high-risk areas. During 1998, few sites had infected mice, but by 1999, 1820 of the high-risk sites contained infected mice and the crude prevalence was 30.8%. Only 118 of the low-risk sites contained infected rodents, and the prevalence of infection was lower (8.3%). Satellite imagery identified environmental features associated with SNV transmission within its reservoir population, but at least 2 years of high-risk conditions were needed for SNV to reach high prevalence. Areas with persistently high-risk environmental conditions may serve as refugia for the survival of SNV in local mouse populations.

Animals↗

PubMed2002

Neonatal sex steroids affect responses to Seoul virus infection in male but not female Norway rats.

Previous studies illustrate that after inoculation with Seoul virus (i.e., the naturally occurring hantavirus found in Norway rats), adult male rats produce higher antibody responses, exhibit higher Th1 responses (i.e., IgG2a, IL-2, and IFN gamma), and shed virus longer than females, but these difference are not altered by manipulation of sex steroids in adulthood. To determine whether sex steroid hormones organize adult responses to hantavirus infection, at 2-4 days of age, male rats were gonadectomized and female rats were injected with testosterone. As adults, animals were inoculated with 10(4)pfu of Seoul virus. Neonatally gonadectomized males (NGM), control females (CF), and neonatal testosterone-treated females (NTF) had lower anti-Seoul virus IgG and IgG2a responses than control males (CM) 20, 30, and 40 days post-inoculation. Neonatal testosterone treatment had no effect on female antibody responses to infection. NGM, CF, and NTF shed virus in saliva and feces for a shorter duration than CM. There was no effect of neonatal hormone manipulation either on the percentage of animals with detectable virus or on the number of virus copies within each target organ. Genetic males, regardless of hormone manipulation, had higher virus replication in lung tissue than did genetic females. Neonatal sex steroids influence the sexual dimorphism in host immune function but do not modify virus replication in target tissues.

Animals↗

PubMed2002

Early exposure to genistein exerts long-lasting effects on the endocrine and immune systems in rats.

BACKGROUND: Although the immunologic effects of endogenous and synthetic estrogens are well studied, few studies have examined the hormonal effects of phytoestrogens (i.e., plant-derived estrogens) on the immune system. The primary goal of this study was to compare the effects of perinatal exposure with life-long exposure to genistein, an estrogenic compound in soy, on the endocrine and immune system in adulthood. MATERIALS AND METHODS: Pregnant female rats were exposed to no, low (5 mg/kg diet), or high (300 mg/kg diet) genistein diets throughout gestation and lactation. At weaning, male offspring exposed to genistein perinatally were either switched to the genistein-free diet or remained on the genistein-dosed diets. At 70 days of age, immune organ masses, lymphocyte subpopulations, cytokine concentrations, and testosterone concentrations were assessed in male offspring. RESULTS: Data were analyzed based on the diets that males were exposed to during gestation and lactation because life-long exposure to genistein had no additional effect on any of the dependent measures. Relative thymus masses were greater among males exposed to the high genistein diet than among males exposed to no genistein. Although the proportions of splenic and thymic CD4+ T cells were not altered by genistein, the percentages of CD4+CD8+ thymocytes, CD8+ splenocytes, and total T cells in the spleen were higher and the percentages of CD4-CD8- thymocytes were lower among males exposed to genistein than among males not exposed to genistein. Synthesis of interferon-gamma (IFN-gamma) was marginally higher and testosterone concentrations were lower among genistein-exposed than genistein-free males. DISCUSSION: These data illustrate that exposure to genistein during pregnancy and lactation exerts long-lasting effects on the endocrine and immune systems in adulthood. Whether exposure to phytoestrogens during early development affects responses to infectious or autoimmune diseases, as well as cancers, later in life requires investigation.

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