Role of nitric oxide in the periaqueductal gray in defensive behavior in mice: influence of prior local N-methyl-D-aspartate receptor activation and aversive condition

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

Bed nucleus of the stria terminalis and the cardiovascular responses to chemoreflex activation

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

Increased pancreatic islet mass is accompanied by activation of the insulin receptor substrate-2/serine-threonine kinase pathway and augmented cyclin D(2) protein levels in insulin-resistant rats

It is well known that glucocorticoids induce peripheral insulin resistance in rodents and humans. Here, we investigated the structural and ultrastructural modifications, as well as the proteins involved in beta-cell function and proliferation, in islets from insulin-resistant rats. Adult male Wistar rats were made insulin resistant by daily administration of dexamethasone (DEX; 1mg/kg, i.p.) for five consecutive days, whilst control (CTL) rats received saline alone. Structure analyses showed a marked hypertrophy of DEX islets with an increase of 1.7-fold in islet mass and of 1.6-fold in islet density compared with CTL islets (P < 0.05). Ultrastructural evaluation of islets revealed an increased amount of secreting organelles, such as endoplasmic reticulum and Golgi apparatus in DEX islets. Mitotic figures were observed in DEX islets at structural and ultrastructural levels. Beta-cell proliferation, evaluated at the immunohistochemical level using anti-PCNA (proliferating cell nuclear antigen), showed an increase in pancreatic beta-cell proliferation of 6.4-fold in DEX islets compared with CTL islets (P < 0.0001). Increases in insulin receptor substrate-2 (IRS-2), phosphorylated-serine-threonine kinase AKT (p-AKT), cyclin D(2) and a decrease in retinoblastoma protein (pRb) levels were observed in DEX islets compared with CTL islets (P < 0.05). Therefore, during the development of insulin resistance, the endocrine pancreas adapts itself increasing beta-cell mass and proliferation, resulting in an amelioration of the functions. The potential mechanisms that underlie these events involve the activation of the IRS-2/AKT pathway and activation of the cell cycle, mediated by cyclin D(2). These adaptations permit the maintenance of glycaemia at near-physiological ranges.

Effect of pH of colloidal suspension on crystallization and activation energy of deep levels in SnO2 thin films obtained via sol-gel

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The Poisson-exponential regression model under different latent activation schemes

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Tobacco smoke-induced left ventricular remodelling is not associated with metalloproteinase-2 or -9 activation

Aim: To investigate the role of MMP-2 and MMP-9 in cardiac remodelling induced by tobacco smoke exposure in rats.Methods: Rats were allocated into two groups: C (n = 9): control animals; ETS (n = 9): exposed to tobacco smoke. After 4months, the animals underwent echocardiography, morphometric study and determination of MMP-2 and MMP-9 activity.Results: ETS rats had larger diastolic (C= 15.6 +/- 1.2 mm/kg, ETS = 18.0 +/- 0.9 mm/kg; p < 0.001) and systolic (C= 7.3 +/- 1.2 mm/kg, ETS = 9.2 0.9 mm/kg; p = 0.001) ventricular diameters adjusted for body weight. Fractional shortening (C= 53 +/- 4.8%, ETS = 48 +/- 3.3%; p = 0.031) and ejection fraction (C= 0. 89 +/- 0.03 5 ETS = 0. 86 +/- 0.02; p = 0.03 0) were smaller in the ETS group. Myocyte cross-sectional area (C= 245 8 mu m(2), ETS=253 8 mu m(2); p = 0.028) was higher in ETS rats. There were no differences in MNtP-2 (C=50 +/- 14%; ETS 43 +/- 11%, p 0.22 +/- 8) or MMP-9 (C=0.36 +/- 0.3%; ETS=0.62 +/- 0.3%, p=0.630) activity between the groups.Conclusion: MMP-2 and MMP-9 did not participate in the remodelling process induced by tobacco smoke exposure. (c) 2007 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.

Platelet activation: ultrastructure and morphometry in platelet-rich plasma of horses

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Modulatory effect of prostaglandins on human monocyte activation for killing of high- and low-virulence strains of Paracoccidioides brasiliensis

The effect of indomethacin (Indo), a cyclo-oxygenase inhibitor, on the monocyte-mediated killing of a low-(Pb265) and a high-(Pb18) virulence strain of Paracoccidioides brasiliensis was examined. The Pb18 strain was not killed by either non-activated or interferon-gamma (IFN-gamma)-activated human monocytes but these cells did show fungicidal activity if pretreated with Indo. In contrast with IFN-gamma tumour necrosis factor-alpha (TNF-alpha) was very effective at stimulating the fungicidal activity of monocytes. While the low-virulence strain, Pb265, could not be killed by monocytes, cells preincubated with IFN-gamma demonstrated fungicidal activity. The killing of this strain was also induced by pretreatment of monocytes with Indo. The results suggest a negative role for prostaglandins, which are synthesized via the cyclo-oxygenase pathway, in the regulation of monocyte-mediated killing of virulent and avirulent strains of P. brasiliensis and that TNF-alpha generation during the fungus-monocyte interaction is more important in the killing of Pb265 than Pb18.

Artificial oocyte activation using calcium ionophore in ICSI cycles with spermatozoa from different sources

The present study evaluated the effect of artificial oocyte activation (AOA) with calcium ionophore A23187 oil intracytoplasmic sperm injection (ICSI) cycles using spermatozoa from different sources. The 314 cycles evaluated were divided into three groups according to sperm origin, the ejaculated group (n = 92), the epididymal group (n = 82). and the testicular roup (n = 140). Each group was further split into experimental subgroups, depending oil whether or no AOA was performed. In additions the cycles of women younger than 36 years were evaluated separately. For each experimental group, ICSI outcomes were compared between subgroups. No significant difference was observed between subgroups for all sperm origin groups. When evaluating only the cycles of women younger than 36 years of age, AOA increased the percentage of high-quality embryos (74.5 versus 53.0%. P = 0.011) and the implantation rate (19.3 versus 10.5%, P = 0.0025) when it was used with ejaculated spermatozoa, and the percentage of high-quality embryos (64.4 versus 50.3%, P = 0.006) when epididymal spermatozoa were used. These results may suggest that both sperm maturity and oocyte quality play a role in oocyte activation. However. this study is to be continued to confirm these findings.

Artificial oocyte activation with calcium ionophore A23187 in intracytoplasmic sperm injection cycles using surgically retrieved spermatozoa

Objective: To evaluate the effect of artificial oocyte activation (AOA) on intracytoplasmic sperm injection (ICSI) cycles using surgically retrieved sperm.Design: Laboratory study.Setting: Fertility/assisted fertilization center.Patient(s): Couples undergoing surgical sperm retrieval for ICSI (n = 204).Intervention(s): Application of calcium ionophore A23187 for AOA.Main Outcome Measure(s): Cycles were divided into experimental groups according to the origin of the sperm used for injection and the type of azoospermia: [1] testicular sperm aspiration in nonobstructive-azoospermic patients (TESA-NOA group, n = 58), [2] TESA in obstructive-azoospermic patients (TESA-OA group, n = 48), [3] and percutaneous epididymal sperm aspiration in obstructive-azoospermic patients (PESA-OA, n = 98). For each experimental group, cycles where AOA was applied (subgroup: activation) were compared with cycles in which AOA was not applied (Subgroup: control). The fertilization, high-quality embryo, implantation, and pregnancy rates were compared among the subgroups.Result(s): For patients undergoing TESA, AOA did not improve ICSI outcomes for either type of azoospermia. However, for cases in which the injected sperm were retrieved from the epididymis, a statistically significantly increased rate of high-quality embryos was observed with AOA.Conclusion(s): Artificial oocyte activation may improve ICSI outcomes in azoospermic patients when epididymal, but not testicular spermatozoa, are injected. (Fertil Steril (R) 2009;92:131-6. (C)2009 by American Society for Reproductive Medicine.)