Physical working conditions in young cattle production in Sweden.

This study investigated physical work environment conditions and sought to identify risk factors in terms of main potential hazards, exposure to physical strain, and the 12-month prevalence of musculoskeletal disorders (MSD) through two postal surveys of Swedish farmers rearing red veal calves (8 to 11 months slaughter age) during April-June 2008 and young bulls (12 to 24 months slaughter age) during March-May 2009. Among 155 red veal producers, the response rate was 45% (n = 59), while among 241 young bull producers finishing 100 or more bulls per year the response rate was 42% (n = 101). A questionnaire was used to obtain general facts about the farm, work time, and frequency of predefined daily and non-daily work tasks. Perceived physical exertion in relation to each work task was assessed by the farmers using the Borg CR-10 scale and further analyzed according to duration and repetitiveness in a physical work strain (PWS) index. The average physical work strain during the predefined work tasks in red veal and young bull finishing was estimated at 3 (moderate strain) on the CR-10 scale. Up to 42% of the surveyed farmers experienced stress and worry about beef production and high levels of potential hazards. High daily work pace and an uncomfortable work climate were other problematic factors. Highly repetitive tasks and physically demanding animal handling were risk factors that increased PWS significantly The 12-month prevalence of MSD was 51% among red veal producers and 65% among young bull producers. Work-related injuries were reported by 20% and 39% of respondents on red veal and young bull farms, respectively, of which 96% and 89% of the cases were related to working with animals.

Increased immunoreactivity of glutathione-S-transferase in the retina of Swiss Webster mice following inhalation of JP8 + 100 aerosol.

The current study was designed to determine whether exposure of mice to aerosolized jet fuel (JP8 + 100) resulted in changes in the cellular distribution or immunoreactivity of the enzyme glutathione S-transferase (GST), a biomarker of toxicant exposure. Male mice were exposed to JP8 + 100 at 1000 mg/m3 or 2500 mg/m3 in aerosol for 1 h per day for 7 days and then sacrificed. The retinas were studied by immunohistochemical methods. The JP8 + 100 exposure caused a marked increase in the immunoreactivity of anti-GSTM antibodies with the radial glial cells of the retina, the Müller cells. These results are consistent with the hypothesis that JP8 + 100 acts as a toxicant to mouse retina by permitting the flux of materials across the blood-retina barrier. The findings are relevant to humans because recent studies indicate that Air Force personnel assigned to clean and maintain fuel pods may be exposed to concentrations of JP8 + 100 exceeding 1000 mg/m3.

Increased levels of glutathione S transferases and appearance of novel alpha class isoenzymes in kidneys of mice exposed to mercuric chloride. I. Biochemical and immunohistochemical studies.

Glutathione S transferases (GST) are a family of enzymes that detoxify electrophilic xenobiotics. This enzyme family was examined in kidneys of mice exposed to mercuric chloride, a known nephrotoxin, because GST have been shown to protect cells against toxicant-induced damage and may serve as biomarkers for toxicant exposure. The purpose of this study was to determine the effect of mercuric chloride on GST activity, isoenzyme levels, and cellular localization in the kidney of Swiss Webster mice. The cellular localizations of alpha, mu, and pi class GST in the kidneys of control and mercuric chloride treated mice were studied immunohistochemically. The GST isoenzyme levels were measured by high-performance liquid chromatography. The mice treated with mercuric chloride had (1) increased amounts of GSTA1/A2 protein in kidney homogenates as compared with controls when analyzed by chromatography and electrophoresis; (2) two new isoforms of the alpha isoenzyme in kidney as demonstrated by Western blot, polyacrylamide gel electrophoresis, and high-performance liquid chromatography, and (3) increased reactivity between antibodies, against GSTA1/A2 or GSTM1 isoenzymes, and cells in the proximal and distal renal tubules as shown by immunohistochemical techniques. The authors conclude that the GSTA1/A2 may protect those cells in the proximal and distal tubules of the renal cortex from toxicant effects of mercuric chloride. This would be one general mechanism for cell protection against a wide variety of toxicants including heavy metals and halogenated aromatics.

Cellular localization of glutathione S-transferases in retinas of control and lead-treated rats.

PURPOSE: The glutathione S-transferases (GSTs) constitute a family of cytosolic isoenzymes that are involved in the detoxication of electrophilic xenobiotics. The purpose of this investigation was to determine the concentration and cellular distribution of the various classes of cytosolic GSTs in the retina of control and triethyl lead-treated rats and thereby reveal mechanisms by which the cells are protected from damage by lead and other toxicants. METHODS: The regional and cellular distribution of cytosolic GSTs in rat retina of control and lead-treated animals was studied by immunohistochemistry. Enzyme activity was determined by a spectrophotometric assay. The GST subunit distribution of the entire retina of control and lead-treated animals was determined and quantified by reverse-phase high-performance liquid chromatography (HPLC). RESULTS: Polyclonal antibodies against mu-class Yb1 and Yb2 GSTs were primarily and strongly reactive with Müller cells and their processes. Anti-Yb1 also reacted with photoreceptor outer segments. Antibodies against two alpha-class GSTs (Ya and Yk) were strongly reactive with Müller cells and their cell processes. Antibodies against Yp and Yc GSTs were reactive with amacrine cells and their processes, and anti-Yp antibodies were reactive against retinal ganglion cells. Treatment of rats with triethyl lead caused diminished reactions of the antibodies against Yb1 and Yp GSTs and increased reactions of anti-Ya with its retinal targets, whereas the total GST activity did not change significantly. CONCLUSIONS: The positive reaction between the amacrine neuronal cells of retina and the anti-Yp and anti-Yc class antisera broadens the class of neurons that contains GST enzymes protective against toxicant insult. It also has been shown that Müller cells are strongly immuno-positive for Yb1 and Yb2 GST. Because these phagocytic cells are in contact with the vitreous fluid and proximate to pigmented epithelial layer of the eye, these GSTs may protect the cells from toxicants accumulated from this fluid.