950 resultados para Prostaglandin E2


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Los efectos de la prostaglandina (PGF2α) vs CIDR y eCG (gonadotrofina coriónica equina) en la dinámica de la población folicular y su relación con las concentraciones plasmáticas de P4 fueron investigadas en ovejas cíclicas. Fueron utilizadas 14 hembras ovinas de la raza Bergamascia; el Grupo 1 (Gl) se sometió a dos aplicaciones de PGF2α, y, el Grupo 2 (G2) tratado con CIDR durante 14 días siendo que, en el momento de su retirada, se administraron 500 UI de eCG. La dinámica folicular ovárica fue monitoreada por medio de ecógrafo. Se monitorearon todos los folículos ≥ mm y se gráfico su posición diariamente, observándose el desarrollo individual folicular. Desde el día anterior a la aplicación de la segunda dosis de PGF2α, (Gl) y desde la administración de eCG (G2) hasta el décimo día del ciclo estral se colectaron muestras de sangre para el análisis de P4. Hubo diferencia significativa (P<0,001) en las concentraciones plasmáticas de P4 entre los tratamientos. La sincronización del estro y ovulación utilizando CIDR + 500 UI de eCG, incrementó la cantidad de folículos reclutados, además de aumentar el diámetro máximo y la tasa de crecimiento de los folículos grandes en la primera onda folicular. En consideración a los resultados se puede concluir que la sincronización del estro y de la ovulación en hembras ovinas, utilizando el CIDR y 500 UI de eCG, incrementa la cantidad de folículos reclutados, además de aumentar el diámetro máximo y la tasa de crecimiento de los folículos grandes. La asociación CIDR+500 UI de eCG provoca aumentos significativos en las concentraciones plasmáticas de progesterona (P4) al inicio de la fase luteal en hembras ovinas.

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The objective was to evaluate the effects of giving prostaglandin F(2 alpha) (PGF) to donor mares 48 h prior to embryo collection. Non-lactating donor mares (n = 20 estrous cycles in 10 mares), ranging from 2.5 to 10 y of age and 400 to 500 kg of body weight were used from September 2004 to February 2005 in the southern hemisphere (Brazil). Donor mares were randomly assigned in a cross-over design study. During a Treated cycle, 7.5 mg PGF was given 48 h prior to embryo collection, whereas in the Control cycle, 7.5 mg PGF was given at embryo collection. In Treated Cycles, serum progesterone concentrations decreased between the day of PGF treatment and the day of embryo collection (13.9 +/- 5.4 and 0.5 +/- 0.3 ng/mL, respectively; P < 0.05). In Treated versus Control cycles, the interovulatory interval was shorter (14.9 +/- 0.9 vs 17.5 +/- 1.1 d, P < 0.05). However, there was no significant difference between these groups for the interval from PGF to ovulation (average, 9.8 d), embryo recovery rate (average, 75%), embryo quality, uterine protein concentration, and pregnancy rate in recipient mares (average, 87% at 15 d after ovulation, with no pregnancy loss detected by 60 d). In conclusion, giving donor mares PGF 48 h prior to embryo collection reduced the average interovulatory interval by approximately 2.5 d, thereby potentially increasing the numbers of embryos that could be collected during a breeding season, with no deleterious effects on embryo recovery rate, embryo quality, or pregnancy rate in recipient mares. (c) 2011 Elsevier B.V. All rights reserved.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The present study aims to compare the effects of lower doses of cloprostenol intramuscular (IM) or into vulvar submucosa (IVS) on estrus induction and pregnancy rate in Nelore cows. A total of 100 cycling Nelore cows with body condition score (BCS 3.5) 1 to 5 scale (Radostitis; Blood, 1986) and 170 +/- 11 days postpartum. Females were randomly divided in 5 groups (N=20) G1 to G5 and treated with cloprostenol (Ciosin (R)) on day 0 (D0) and on day 11 (D11) if not detected in estrus. Cows were injected with 500 mu g IM (G1), 250 mu g IM (G2), 125 mu g IM (G3), 250 mu g IVS (G4) and 125 mu g IVS (G5). Estrus was observed twice a day and the females artificially inseminated 12 hours after heat detection. There was no statistical difference (P>0.80) between groups in the estrus induction (first injection to estrus interval): 16/20-96.00 hours (G1), 13/20-90.42 hours (G2), 10/20-84.45 hours (G3), 15/20-87.86 hours (G4), 12/20-81.25 hours (G5) and second injection (P>0.10): 4/20-67.50 hours (G1), 7/20-85.50 hours (G2), 10/20-57.00 hours (G3), 5/20-70.60 hours (G4), 8/20-60.00 hours (G5). There was no statistical difference (0.65(ns)) between groups in the pregnancy rates: 40% (G1), 45% (G2), 50% (G3), 40% (G4), 40% (G5). The results demonstrate that the treatments with lower doses of cloprostenol intramuscular or into vulvar submucosa may be used to induce heat with similar pregnancy rates in cycling Nelore cows with good body condition.

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The objective was to compare pharmacological strategies aiming to inhibit prostaglandin F2 alpha (PGF(2 alpha)) synthesis (flunixin meglumine; FM), stimulate growth of the conceptus (recombinant bovine somatotropin; bST) and progesterone (P(4)) synthesis (human chorionic gonadotropin; hCG), as well as their combinations, regarding their ability to improve pregnancy rates in beef cattle. Lactating Nelore cows (N = 975), 35 to 70 days postpartum, were synchronized and inseminated by timed artificial insemination (TAT) on Day 0. on Day 7, cattle were allocated into eight groups and received one of the following treatments: saline (S) on Days 7 and 16 (Group Control); S on Day 7 and FM on Day 16 (Group FM); bST on Day 7 and S on Day 16 (Group bST); bST on Day 7 and FM on Day 16 (Group bST + FM); hCG on Day 7 and S on Day 16 (Group hCG); hCG on Day 7 and FM on Day 16 (Group hCG + FM); bST and hCG on Day 7 and S on Day 16 (Group bST + hCG), or bST and hCG on Day 7 and FM on Day 16 (Group bST + hCG + FM). The aforementioned treatments were administered at the following doses: 2.2 mg/kg FM (Banamine (R); Intervet Schering-Plough, Cotia, SP, Brazil), 500 mg bST (Boostin (R); Intervet Schering-Plough), and 2500 IU hCG (Chorulon (R); Intervet Schering-Plough). Pregnancy diagnosis was performed 40 days after TAI by transrectal ultrasonography. Pregnancy rates were not significantly different among treatments. However, there was a main effect of hCG treatment to increase pregnancy rates (63.0 vs. 55.4%; P = 0.001). Concentrations of P(4) did not differ significantly among groups on Day 7 or on Day 16. However, consistent with the higher pregnancy rates, hCG increased P(4) concentrations on Day 16 (10.6 vs. 9.6 ng/mL, respectively; P = 0.05). We concluded that hCG treatment 7 days after TAI improved pregnancy rates of lactating Nelore cows, possibly via a mechanism leading to induction of higher P(4) concentrations, or by reducing the luteolytic stimulus during maternal recognition of pregnancy. (C) 2011 Elsevier B.V. All rights reserved.

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Histamine release from guinea pig heart treated with compound 48/80 was potentiated by the cyclooxygenase inhibitors indomethacin and piroxicam but not by aspirin or phenylbutazone. This differential effect suggests that the potentiation is not merely due to an inhibition of prostaglandin synthesis. Piroxicam potentiated the histamine release induced by cardiac anaphylaxis whereas indomethacin reduced this effect. The SRS-A antagonist FPL 55712 inhibited histamine release induced by cardiac anaphylaxis, but not that evoked by compound 48/80, and also prevented the potentiation due to indomethacin and piroxicam. In total, these data suggest that the potentiation of histamine release by piroxicam and indomethacin is probably due to a diversion of arachidonic acid metabolism from the cyclooxygenase to the lipoxygenase pathways. The resulting lipoxygenase products may then regulate histamine release, with the secretion due to antigen being more sensitive to such modulation than that evoked by compound 48/80.

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The authors looked for the verification of the fatigue of retentive clasps utilized on the removable partial denture. According to this, it was idealized and built on assay machine, that through movements, simulate the insertion and removal of the clasp for a pattern tooth, manufactured on cobalt-chromium which has all the preparation normally utilized to the correct confection of this type of prosthesis. It was utilized three different commercial alloys based on cobalt-chromium: L1-Biosil; L2-Steldent; L3-Duracron. It was utilized the T clasp of Roach, with was tested upon three different proportions among width and thickness: E1-1.7;E2-2.0 and E3-2.3 and was casted through two casting techniques: F1-oxygen-gas and F2-oxygen-acetylene. The clasps were tested on the machine, which allowed the reading of the number of insertion and removal cycles made until fatigue appeared. The obtained results were submitted to the statistic analysis and the authors concluded that: a) L3 (Duracrom) obtained the best results followed by L1 (Biosil) and finally L3 (Steldent); b) among the analyzed thickness, the best results were obtained by E3, followed by E2 and after this E1; c) form the casting techniques, F2 gave us the best results.

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The authors tested the T clasp of Roach in three differents proportions among width and thickness: E1-1.7; E2-2.0 and E3-2.3, with a constant length of 15 mm. These clasps were casted with three cobalt-chromium alloys (L1-Biosil; L2-Steldent and L3-Duracrom), through two casting techniques (F1-oxygen-gas and F2-oxygen-acetylene). The fatigue of the clasps were verified by using and assay machine, that through movements, simulate the insertion and removal of the clasps for a pattern which were obtained from a premolar, prepared in a surveyor. This machine detect the fatigue of the clasps and count the number of cycles of insertion and removal realized. The obtained results of the interaction between the analysed factors, were submitted to the statistic analysis and the authors concluded that: a) the interaction of factors, Alloy x Thickness, Alloy x Casting Technique and Thickness x Casting Technique did not change the order of effects that the factors showed separately but gave rise to effects of different magnitude for any observed sense; b) the simultaneous interaction of the factors Alloy x Thickness x Casting Technique confirmed the superiority of the L3 alloy, the thickness E3 and the F2 casting technique.

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Norepinephrine (NE) and clonidine produce a phasic, dose-dependent contraction of the isolated guinea-pig terminal ileum. The effect of NE was blocked by prazosin which produced a parallel rightward shift of the concentration-effect curve to NE, with a significant depression of maximum effects. Yohimbine and indomethacin noncompetitively blocked, whereas practolol potentiated, the contractile effect of NE. The contractile effect of clonidine was not antagonized by indomethacin or atropine. These results suggest that the isolated guinea-pig terminal ileum has excitatory receptors sensitive to clonidine stimulation and excitatory alpha receptors sensitive to blockade by prazosin, and that the activation of the latter may be related to the activation of endogenous prostaglandin synthesis.

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The present studies were conducted to determine the role of prostaglandins in the etiology of a rise of body temperature observed in rats after electrolytic lesion made on the dorsal mesencephalic areas. This hyperthermia was abolished by intraperitoneal administration of indomethacin, an inhibitor of prostaglandins synthesis. These results strengthen the suggestion of a similar mechanism for both neurogenic hyperthermia and the fevers produced by pyrogens. However, until further experiments are carried out, the possibility of lesion in producing hyperthermia by different mechanisms cannot be ruled out.