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Biomedical subjects

G Hotter

Publications and source records attributed to G Hotter.

72 records · Page 4Linked to original sources
PubMed1992

Human and experimental studies on renal eicosanoid response to long-term cadmium exposure.

In order to assess the effects of long-term exposure to cadmium (Cd) on the renal metabolism of eicosanoids, the urinary excretion of 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), prostaglandin E2 (PGE2), prostaglandin F2 alpha (PGF2 alpha), and thromboxane B2 (TXB2) was determined in 37 workers exposed to Cd and in female Sprague-Dawley rats given 100 ppm Cd in drinking water for 10 months. Urinary output of sodium and calcium was also determined. The Cd-exposed workers showed an increased urinary concentration of 6-keto-PGF1 alpha, PGE2, sodium, and calcium. The rise of 6-keto-PGF1 alpha was related to Cd levels in blood and weakly correlated with urinary sodium. Calcium in urine was not related to the concentration of the metal in blood and urine. A slight elevation in urinary TXB2 was also observed in workers with blood Cd higher than 5 micrograms/liter. After 10 months of exposure to Cd, female Sprague-Dawley rats presented an enhanced urinary excretion of albumin, transferrin, beta 2-microglobulin, sodium, and PGE2 in urine. The latter was significantly correlated with albuminuria and transferrinuria. In conclusion the results show that chronic exposure to Cd induces changes in the urinary excretion of some eicosanoids. The possible relation of these changes to Cd-induced kidney dysfunction are discussed.

6-Ketoprostaglandin F1 alpha↗
PubMed1992

Pancreas prostanoid production in ischemia and reperfusion.

This study was carried out to investigate the proportion of the 6-keto prostaglandin F1 alpha (6-keto PGF1 alpha) and thromboxane B2 (TXB2) alteration that is due to ischemia in pancreas transplantation against the proportion due to reperfusion. For this purpose, Lewis rats were divided in three experimental groups: Group I = Control, Group II = Donor pancreas subjected to 15 minutes of cold ischemia, Group III = Same as group II but pancreas were transplanted to the recipient individual and then subjected to reperfusion. The results indicate that increases in pancreas 6-keto PGF1 alpha occur as a consequence of cold ischemia while TXB2 remains unchanged. When blood flow was restored, 6-keto PGF1 alpha remained unchanged compared to the ischemic group while pancreatic levels of TXB2 were significantly increased. These results suggest a different induction of prostanoid metabolism during ischemia and reperfusion in pancreatic tissue.

6-Ketoprostaglandin F1 alpha↗
PubMed1992

Altered systemic and tissue prostacyclin in cerulein induced acute pancreatitis in rats.

Prostacyclin metabolism in rat acute pancreatitis was evaluated by measuring the tissue levels of 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) and the urinary excretion of 2, 3-dinor 6-keto-PGF1 alpha. Acute pancreatitis was induced by i.v. cerulein perfusion and was confirmed by the pancreas enzyme changes and the histological findings. Significantly enhanced tissue and urinary prostacyclin levels were found in acute pancreatitis rats, when compared to the controls. Concomitantly, an enhanced tissue phospholipase A2 (PLA2) activity was also found. These data show the importance of 2, 3-dinor PGF1 alpha as an inflammatory marker in cerulein-induced pancreatitis.

6-Ketoprostaglandin F1 alpha↗
PubMed1991

Altered levels of tissue and urinary prostacyclin in rats subjected to pancreas transplantation.

Significant increases of TXB2 and PGE2 are reported to occur in pancreas transplantation. These increases are prevented with scavengers of oxygen-free radicals. In this communication, we report on changes of prostacyclin metabolites such as tissue 6-keto prostaglandin F1 alpha and urinary 2,3-dinor 6-keto prostaglandin F1 alpha in rats subjected to pancreas transplantation after different periods of organ cold preservation ischemia as well as the effect of superoxide dismutase (SOD) on these changes. For this purpose, male Lewis rats were classified as follows: Group I, Control; Group II, syngenic pancreas transplantation after 15 min of organ preservation in Collins solution at 4 degrees C; Group III, same as II but with 12 hours of organ preservation; Group IV, same as III, but with SOD pretreatment. Results have shown significant posttransplantation increases of both tissue 6-keto PGF1 alpha and urinary 2, 3 dinor 6-keto PGF1 alpha, the latter being a useful marker to evaluate systemic prostacyclin (PGI2) production by rat pancreas. This effect was prevented when the organ had been exposed to SOD during the period of cold preservation ischemia. These results confirm the implication of oxygen-free radicals (OFR) in the ischemia-reperfusion process associated to rat pancreas transplantation leading to enhanced arachidonic acid metabolism.

6-Ketoprostaglandin F1 alpha↗
PubMed1991

Tissular prostanoid release, phospholipase A2 activity, and lipid peroxidation in pancreas transplantation.

Free radical species have been implicated as important agents in ischemia-reperfusion injury associated to transplantation procedures. This study was carried out to investigate the possible relationship between phospholipase A2 activity (PLA2), lipoperoxidation, and the changes in arachidonic acid metabolism during ischemia reperfusion injury in pancreas transplantation, as well as the effect of a free radical scavenger such as superoxide dismutase on these changes. For this purpose male Lewis rat groups (n = 7) were classified as follows: group I--control; group II--syngenic pancreas transplantation after 15 min preservation in Collins solution at 4 degrees C; group III--syngenic pancreas transplantation after 18 hr preservation in the same conditions; group IV--same as III but with administration of SOD (i.v.) immediately before revascularization in the recipient rat. The results indicate that significant increases in PLA2 activity and lipoperoxide levels occur concomitantly with an increase of thromboxane B2 (TXB2) and 6-keto prostaglandin F1 alpha (6-keto PGF1 alpha) in pancreatic tissue after pancreas transplantation. The counteracting effect of a free radical scavenger such as SOD supports the role of oxygen free radicals (OFR) mediating activation of PLA2 and subsequent formation of eicosanoids in pancreas transplantation.

Animals↗
PubMed1990

Prostaglandin E2 and thromboxane B2 levels in rats subjected to pancreas transplantation.

This work undertakes the study of changes in urinary, plasmatic and tissue levels of Thromboxane B2 (TXB2) as well as in tissue Prostaglandin E2 (PGE2) after pancreas transplantation and the effect of superoxide dismutase (SOD) on these changes. For this purpose, streptozotocine induced diabetic rats were subjected to pancreas transplantation. Experimental groups were classified as follows: Group I: Control; Group II: Animals subjected to 15 min of pancreas arterial flow occlusion followed by reperfusion; Group III: Syngenic pancreas transplantation after 12 hours of organ preservation; Group IV: Same as III, but with additional SOD (13 mg/kg) pretreatment. The results indicate that significant increases of PGE2 and TXB2 levels occur as a consequence of the surgical removal, preservation and implantation of the organ. For TXB2 these increases, immediate in plasma and tissue, are not detected in urine until 24 hours after transplantation of the pancreas. The release of TXB2 and PGE2 was effectively prevented in the SOD treated group supporting the role of oxygen free radicals and lipid peroxidation in the processes of ischemia-reperfusion associated to transplantation of the pancreas.

Animals↗
PubMed1989

Modern high-performance liquid chromatographic-radioimmunoassay strategies for the study of eicosanoids in biological samples.

An evaluation of the most recent literature on the determination of eicosanoids by immunoassay methods confirms that owing to the inherent lack of specificity of many of the antibodies used for this purpose, immunological assays (radioimmunoassay or enzyme immunoassay) are often preceded by solid-phase extraction followed by further purification of the antigens of interest by routine reversed-phase high-performance liquid chromatographic methods. In this way the analytical potential of radioimmunoassay is remarkably enhanced and accuracy and precision of the assay are ensured.

Animals↗
PubMedDate not supplied

Application of totally automated on-line sample clean up system for extraction and high-performance liquid chromatography separation of peptide leukotrienes.

We have developed a fully automated on-line extraction-purification method for peptide leukotrienes in biological fluids using a column-switching technique. Individual leukotrienes in HPLC-collected fractions are determined by immunoassay techniques. Leukotrienes were extracted from nasal lavage samples and eluted from the solid-phase extraction cartridge into the HPLC column with methanol-ammonium acetate buffer (60:40, v/v) pH 5.4, as a mobile phase. This method provides good recoveries, excellent resolution of leukotrienes and is suitable to be combined with off-line radioimmunoassay (RIA) or enzymoimmunoassay (EIA). The most important losses are observed after evaporation-concentration and lyophilization. We also have compared RIA with EIA determination. Significant differences are found between RIA values and EIA values.

Autoanalysis↗
PubMedDate not supplied

Xanthine oxidase activation in cerulein- and taurocholate-induced acute pancreatitis in rats.

Oxygen free radicals (OFR) are postulated to play a role in the pathogenesis of acute pancreatitis. The aim of this work was to examine the role of xanthine oxidase in the generation of OFR and the activity of the endogenous defense mechanisms as reflected by pancreatic superoxide dismutase (SOD) activity in a model of edematous pancreatitis induced in rats by administration of cerulein at supramaximal doses, as well as in necrohemorrhagic model induced by intraductal administration of sodium taurocholate. Comparison between these two models of pancreatitis suggests important differences in origin and importance in the evolution of injury. In necrohemorrhagic pancreatitis OFR can be produced by xanthine oxidase activity probably associated to cell death. By contrast, in cerulein induced pancreatitis, other sources of oxygen free radicals, such as inflammatory cells, can be of more importance.

Acute Disease↗