Immune homeostasis in the permanent inhabitants of mountain regions

Based on the study of 66 miners in the subclinical stage of manganotoxicosis the principle functional changes have been ascertained in the given condition. Revealed in the above series were an increased content of manganese in the hair of more than 3 mg% (95.5%-100.0%), the presence of neurosis-like condition presenting with elements of somatized depression, anxiety, asthenization, slight decline in the mnestic functions (69.6%-93.5%), mild impairment of the power of voluntary movement, parasympathetic type vegetative dystonia (42%-73.7%), slight changes in cerebral and peripheral hemodynamics (36.6%-68.6%), disordered bioelectrical activity of muscles of the extrapyramidal type (53.7%-83.2%), breakdown of mechanisms of adaptation of the sympathoadrenal (19.1%-49.3%) and cholinergic (26.3%-57.9%) systems.     

Glutathione modulates lipid composition of human colon derived HT-29 cells

Glutathione (GSH) is important in maintaining intracellular thiol status. The present study looked at the effect of GSH depletion on lipid composition of colon-derived HT-29 cells. GSH was depleted in HT-29 cells by incubation either with buthionine-S, R-sulfoximine (BSO) or diethylmaleate (DEM). GSH was restored during early periods of cells growth by supplementation of growth medium with either GSH ester or N-acetyl cysteine (NAC). Lipids were analysed following GSH depletion and supplementation. Among the neutral lipids, an increase in free cholesterol and diacylglycerol and decrease in cholesteryl ester and triacylglycerol were seen in GSH-depleted cells as compared to control cells. There were no detectable free fatty acids either in control or GSH-depleted cells. Among the phospholipids, a decrease in phosphatidylcholine and phosphatidylinositol and an increase in phosphatidylethanolamine were observed. These changes were a completely reversed by supplementation of BSO-treated cells with GSH ester and partially reversed by N-acetyl cysteine. These results suggest that the GSH status of the cell plays an important role in the lipid composition of the cells.     

Electromyographic response of the labial muscles during normal liquid swallows using a spoon, a straw, and a cup

PURPOSE: To determine if ethnic and gender differences in smoking (lifetime prevalence and 30-day prevalence) exist among a cohort of Asian, black, Hispanic, and white inner-city adolescents during the 3-year middle school period. METHODS: Students in 22 urban schools completed self-report questionnaires and provided carbon monoxide breath samples at three annual assessments. Chi-square analyses were conducted to test for associations between ethnic group (Asian, black, Hispanic, and white) and smoking and to test for gender differences in smoking within each ethnic group. Additional analyses examined differences in smoking between two Hispanic subgroups (Puerto Rican and Dominican). RESULTS: Ethnicity was associated with lifetime smoking prevalence at all three assessment points but was only associated with 30-day smoking prevalence at the 2-year follow-up. However, there were no differences in smoking between Puerto Rican and Dominican youth. Black girls reported higher lifetime smoking prevalence than black boys at all three assessments. At the 2-year follow-up, Asian boys reported higher lifetime smoking prevalence than Asian girls; Hispanic girls reported higher 30-day prevalence than Hispanic boys. CONCLUSIONS: White and Hispanic adolescents were at higher risk for smoking relative to Asian and black adolescents. With the exception of white youth, gender differences were found within each ethnic group.     

Capillary electrophoretic study of the complex formation between DNA and cationic surfactants

Due to the growing interest in the use of cationic surfactants for the construction of liposomal genetic delivery systems, the study of complex formation between DNA and quaternary ammonium detergents is of fundamental importance. In this context, we undertook the study of this complex formation using capillary zone electrophoresis (CZE) with suppressed electroosmotic flow, a technique that allowed us to both monitor the change in mobility of DNA as a function of added surfactant in a precise and reproducible manner and evaluate the potential of CZE to reflect the change in hydrodynamic friction upon binding. Nevertheless, CZE must be applied with caution for binding studies where strong cooperativity occurs, because of the presence of peak splitting at concentrations close to the half-point of binding. Also, a comparison between this experiment and Manning's polyelectrolyte transport properties theory on one hand and Tirado and Garcia de la Torre expression for hydrodynamic friction of rod-like molecules on the other hand is given.     

Ectopic expression of metallothionein-III causes pancreatic acinar cell necrosis in transgenic mice

Mice express four distinct metallothioneins (MTs) that have similar metal-binding properties. MT-I and MT-II are expressed coordinately in most organs, whereas MT-III is expressed predominantly in a subset of neurons and MT-IV is expressed in certain stratified epithelia. The restricted expression of MT-III suggests that it may severe a specialized function. To test this hypothesis, transgenic mice were generated that express MT-III in the wider expression domain of MT-I. Similar transgenic lines expressing extra MT-I under the same regulation were generated as controls for the effect of over-expression of MT. Transgenic mice that express MT-III ectopically frequently die at 2-3 months of age. The pancreata of moribund mice were abnormally small and histological examination, at various ages, revealed a progressive degeneration of the acinar cells. At early stages multifocal acinar cell eosinophilia and swollen nuclei were seen and this pathology progressed to multifocal acinar cell necrosis and fibrosis. The terminal stages were characterized by a loss of the acinar compartment, leaving the islets embedded in a fibrotic remnant. Other organs of these mice were grossly and histologically normal. All organs examined from mice expressing excess MT-I were unremarkable even though expression of either MT-I or MT-III transgenes resulted in similar accumulations of zinc and copper in the pancreata. This study indicates that pancreatic acinar cells are unusually sensitive to chronic expression of MT-III. The mechanism by which MT-III disrupts pancreatic function is unclear, but the results provide further evidence that MT isoforms exhibit distinct properties and probably serve distinct biological functions.     

Response of V79 cells to low doses of X-rays and negative pi-mesons: clonogenic survival and DNA strand breaks

Mammalian cells are hypersensitive to very low doses of X-rays (< 0.2 Gy), a response which is followed by increased radioresistance up to 1 Gy. Increased radioresistance is postulated to be a response to DNA damage, possibly single-strand breaks, and it appears to be a characteristic of low linear energy transfer (LET) radiation. Here we demonstrate a correspondence between the extent of the increased radioresistance and linear energy transfer of 250 kVp X-rays and plateau and Bragg peak negative pi-mesons. The results support our hypothesis since the size of the increased radioresistant response appears to correspond to the number of radiation induced single-strand breaks. Furthermore, since survival prior to the increased radioresistant response (< 0.2 Gy) was LET-independent, these data support the notion that the increased radioresistant response may dictate the overall survival response to higher doses. However, while these data provide further circumstantial evidence for the involvement of DNA strand breaks in the triggering of increased radioresistance, more direct conclusions cannot be made. The data are not accurate enough to detect structure in the single-strand break profiles, the production of single-strand breaks being apparently linear with dose.