The effects of magnesium sulphate on the contractile activity of uterus in an animal model of preeclampsia.

PURPOSE: This study was undertaken to evaluate the effects of magnesium sulfate (MgSO4) on the contractile activity of the uterus in a pregnant rat model of preeclampsia induced by N-nitro-arginine methyl ester (L-NAME). MATERIALS AND METHODS: Twenty-eight, 160-220 gram, three to four month old female Sprague-Dawley rats were used in this study. After conception was confirmed by vaginal smears on the first day of pregnancy, the animals were allocated into four groups according to the chemicals fed in their drinking water as control (nothing administered), L-NAME (50 mg/kg L-NAME), MgSO4 (600 mg/kg MgSO4), and MgSO4 + L-NAME group (600 mg/kg MgSO4 + 50 mg/kg L-NAME). The pregnant uterus strips were isolated on the 19th day and the contractile activity of uterus was examined by applying 0, 0.1, 0.2, 0.4, 0.8, and 2.5 mIU/ml oxytocin to each group and responses are recorded accordingly. RESULTS: There were no statistically significant differences regarding fetal parameters and peak amplitudes of the oxytocin stimulated pregnant rat myometrial strips among groups. In L-NAME group at 0 and 0.1 mIU/ml oxytocin, the contraction frequency in a ten-min period was statistically lower than the control group (Z = -2.850, p = 0.004; Z = -2.902, p = 0.004, respectively). In MgSO4 group only at 0 mIU/ml oxytocin, the frequencies of the contractions in ten-min period were statistically lower than the control group (Z = -2.973,p = 0.003). In L-NAME + MgSO4 group at 0, 0.1 and 0.2 mIU/ml oxytocin concentrations the frequencies of the contractions in ten-min period were statistically lower than the control group (Z = - 4.018, p = 0.000; Z = -3.237, p = 0.001; Z = -2.902, p = 0.004, respectively). In L-NAME + MgSO4 given group at each oxytocin concentrations, the frequencies of the contractions in ten-min period were lower but not statistically different than the L-NAME group. CONCLUSION: MgSO4 has no significant effect on the amplitude of spontaneous or oxytocin induced myometrial contractions, but decreased the frequency of spontaneous contractions. At each doses of oxytocin, MgSO4 has no significant effect on the frequency of contraction in a pregnant rat model of preeclampsia induced by L-NAME.

The effects of levamisole on oxidative stress induced by copper intoxication in broilers.

AIM: To determine the effects of Cu and levamisole on concentrations of Cu and Fe in plasma and liver, and the effects of levamisole on lipid peroxidation induced by Cu intoxication in broiler chickens. METHODS: In a 2×4 factorial study, 80 one-day-old Ross PM3 broiler chicks were fed diets for 21 days containing either 8 mg/kg Cu (Low Cu) or 250 mg/kg Cu (High Cu) and were treated with 0 (L0), 4 (L4), 8 (L8) or 16 (L16) mg/kg bodyweight levamisole per day from Day 7 of the study, on three consecutive days in their drinking water. This treatment was repeated three times, at 3-day intervals. On Day 21, blood samples were collected from each bird for analysis of concentrations of Cu, Fe and malondialdehyde, and activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), superoxide dismutase, catalase and glutathione peroxidase (GSH-Px). The birds were killed and liver samples collected for analysis of Cu and Fe. RESULTS: Mean concentrations of Cu and Fe in plasma, and Cu in liver, were increased overall in the High Cu groups compared with the Low Cu groups (p<0.001). Compared with the L0 treatment group on the High Cu diet, treatments L4, L8 and L16 decreased concentrations of Cu in plasma, and L8 and L16 increased concentration of Cu in liver (p<0.05). Mean activities of AST and ALT were increased in untreated birds (L0) fed the High compared with Low Cu diets (p<0.01). In birds receiving the High Cu diet, treatments L4 and L8 decreased activities of AST, and L4 and L16 decreased activity of ALT, compared with L0 (p<0.05). The High Cu diet induced an oxidative stress characterised by increased mean concentrations of malondialdehyde and decreased activities of superoxide dismutase, catalase and GSH-Px (p<0.001). Concentration of malondialdehyde, and activities of superoxide dismutase and catalase were not changed following levamisole treatment in birds on the High Cu diet, and activity of GSH-Px was decreased by the L4 and L8 treatments compared with the L0 group. CONCLUSIONS AND CLINICAL RELEVANCE: The results of the study suggest that treatment with levamisole might alleviate the harmful effects of Cu on the liver, as demonstrated by decreased activities of AST and ALT induced by a diet containing 250 mg/kg Cu.

Size distribution of luteal cells during pseudopregnancy in domestic cats.

Experiments were designed to investigate the size distribution of queen steroidogenic luteal cells throughout pseudopregnancy. Corpora lutea were obtained from the queens following ovariohysterectomy on days 7, 15 or 25 of pseudopregnancy. Luteal cells were isolated from the ovary by collagenase digestion. Steriodogenic cells were identified by staining of cells for 3beta-HSD activity. Cell diameters were measured using a microscope. Luteal cells having steroidogenic capacity covered a wide spectrum of sizes ranging from 3 to 35 mum in diameter. There was a significant increase in mean cell diameters (p < 0.01) as pseudopregnancy progressed. Mean diameter of 3beta-HSD positive cells increased from 10.41 +/- 0.7 microm, on day 7 of pseudopregnancy, to 19.72 +/- 1.3 microm on day 25 of pseudopregnancy. The ratio of large (>20 microm in diameter) to small (3-20 microm in diameter) luteal cells was 0.08 : 1.0 on day 7 of pseudopregnancy, with the 7.5-10 microm cell size class predominant. By day 25 of pseudopregnancy, the ratio of large-to-small cells was increased to 0.87 : 1.0, and 20-25 microm cell sizes become predominant. In conclusion, this study has demonstrated that the cells of the corpus luteum undergo continuous differentiation during pseudopregnancy in queen. This study also demonstrates that luteal cells dissociated from pseudopregnant queen can be used as a model to study the physiology of corpus luteum in pregnant cats.