426 resultados para BRACHIAL PLEXUS


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The objective of this paper was to study the effect of sympathetic innervation on morphological and histochemical aspects of skeletal muscle tissue. Rabbit masseter muscle was studied using histochemical and immunohistochemical methods for periods of up to 18 months post-sympathectomy. The morphological and enzymatic characteristics of control masseter muscles were similar on both the left and right sides. The main features were muscle fibres with a mosaic pattern and a predominance of type IIa fibres, followed by type I. Type IIb fibres showed very low frequency. Sympathectomized animals showed varying degrees of metabolic and morphological alterations, especially 18 months after sympathectomy. The first five groups showed a higher frequency of type I fibres, whilst the oldest group showed a higher frequency of type lib fibres. In the oldest group, a significant variation in fibre diameter was observed. Many fibres showed small diameter, atrophy, hypertrophy, splitting, and necrosis. Areas with fibrosis were observed. Thus cervical sympathectomy induced morphological alterations in the masseter muscles. These alterations were, in part, similar to both denervation and myopathy. These findings indicate that sympathetic innervation contributes to the maintenance of the morphological and metabolic features of masseter muscle fibres.

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The aim of this study was to analyze the morphoquantitative features of the nitrergic myenteric neurons from the body of the stomach of diabetic rats. The body of the stomach of five normoglicemic rats and of five diabetic rats were prepared as whole-mounts stained by the histochemical technique of NADPH-diaphorase. Decreased body weight and increased daily ingestion of water, fast glicemia and glycated hemoglobin were verified in diabetic animals. According to the data obtained, significant difference in the density of nitrergic neurons was not observed between the two groups, but the areas of the neuronal cell body profiles in the diabetic rats were significantly larger. Results showed that the streptozotocin that induced diabetes does not accelerate the death of the nitrergic neurons, but increases the expression of these cells.

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In this study we investigated the effect of the acetyl-L-carnitine (ALC) supplementation on the myenteric neurons of the jejunum of rats made diabetic at the age of 105 days by streptozotocin (35 mg/kg body weight). Four groups were used: non-diabetic (C), non-diabetic supplemented with ALC (CC), diabetic (D), diabetic supplemented with ALC (DC). After 15 weeks of diabetes induction the blood was collected by cardiac puncture to evaluate glycaemia and glycated haemoglobin. Next the animals were killed and the jejunum was collected and subjected to whole-mount preparation to evidence the myenteric neurons through the histochemical technique of the NADH-diaphorase. The neuronal counts were made in 80 microscopic fields, in tissue samples of five animals of each group. The profiles of the cell bodies of 1000 neurons per group were analysed. Diabetes induced a significant increase in the area of the cell body and decrease in the number of NADH-diaphorase positive myoenteric neurons. ALC suplementation to the diabetic group promoted smaller hypertrophic effects and less neuronal loss than in the myoenteric neurons of the diabetic rats, and in addition diminished the body weight decrease and reduced the fasting glycaemia. © 2005 Blackwell Verlag.

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The present study had the objective of evaluating calcium accumulations in muscle fibers and their correlation with the canine muscular dystrophy. After the deaths of the animals (13 dystrophic and 3 non-dystrophic), samples of the skeletal muscles were collected. The material was stained with hematoxylin-eosin, Gomori's modified trichrome and alizarin red S technique (pH 4.3). The histopathological changes were analyzed and the proportions of calcium-positive (CPF) and negative muscle fibers were evaluated. Histopathological changes such as muscle fiber diameter changes, necrosis, hyalinization, presence of inflammatory infiltrate and fatty atrophy were identified in all the dystrophic muscles. Statistically significant differences in numbers of CPF between dystrophic muscles and non-dystrophics were observed for the masseter (6%), brachial biceps (5%) and triceps, sartorius and femoral biceps (4%) muscles. The identifying calcium is of interest as a parameter for helping in diagnostic screening.

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Although canine visceral leishmaniasis (CVL) has been extensively studied, muscular damage due to Leishmania (Leishmania) infantum chagasi infection remains to be fully established. The aim of this study was to describe the electromyographic and histological changes, as well as search for the presence of amastigote forms of Leishmania spp, CD3+ T-lymphocytes, macrophages and IgG in skeletal muscles of dogs with visceral leishmaniasis (VL). Four muscles (triceps brachial, extensor carpi radialis, biceps femoris and gastrocnemius) from a total of 17 naturally infected and six healthy dogs were used in this study. Electromyographic alterations such as fibrillation potentials, positive sharp waves and complex repetitive discharges were observed in, at least, three muscles from all infected dogs. Myocyte necrosis and degeneration were the most frequent muscular injury seen, followed by inflammatory reaction, fibrosis and variation in muscle fibers size. Immunohistochemistry in muscle samples revealed amastigote forms in 4/17 (23. 53%), IgG in 12/17 (70. 58%), CD3+ T-lymphocytes in 16/17 (94. 12%) and macrophages in 17/17 (100%) dogs. Statistically positive correlation was observed between: inflammatory infiltrate (p=0. 0305) and CD3+ immunoreaction (p=0. 0307) in relation to the number of amastigote forms; inflammatory infiltrate (p=0. 0101) and macrophage immunoreaction (p=0. 0127) in relation to the amount of CD3+; and inflammatory infiltrate (p=0. 0044) and degeneration/necrosis (p<0. 0001) in relation to the presence of macrophages. Our results suggest that different mechanisms contribute to the development of myocytotoxicity, including celular and humoral immune responses and direct muscular injury by the parasite. Nevertheless, the catabolic nature of the disease can probably interact with other factors, but cannot be incriminated as the only responsible for myositis.

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The aim of this study was to evaluate the electromyographic and histopathological changes in skeletal muscles of dogs naturally infected by L. infantum. Twenty five mixed breed adult dogs with parasitological, molecular and serological diagnosis were selected. The evaluated muscles were: triceps brachial, extensor carpi radialis, biceps femoris and gastrocnemius. One dog had locomotor clinical signs with hind limbs paresis associated with severe muscle atrophy. Twenty-three (92%) had some type of muscular change, and in 22 (88%) such changes were directly identified by electromyography. Even without any clinical signs of the disease, 10 (40%) dogs had electromyographic and histopathological changes. Leishmania antigens were detected in muscles of four (16%) dogs. The electromyographic evaluation indicated the occurrence of chronic polymyositis in 13 (52%) dogs, the presence of both acute and chronic muscle inflammation four (16%), acute myopathy in two (8%) and absence of electromyographic abnormalities in three (12%) dogs. The most frequently observed histopathological changes were degeneration and necrosis of myofibers and inflammatory infiltration observed in 12 (48%) dogs. Other changes were decreased diameter of muscle fibers in 15 (60%) and peri or endomysial fibrosis in 14 (56%) animals. The changes observed in the present study showed that even in the absence of clinical signs, most dogs infected by Leishmania infantum have chronic polymyositis.

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

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The 2,4 dichlorophenoxyacetic acid (2,4-D) is a systemic herbicide whose effects in animal organic systems have been examined in previous studies, being the neurotoxicity considered the predominant effect. However, the studies that detect the 2,4-D neurotoxicity have merely focused in the central nervous system, and therefore, little is known about the effect of this herbicide in the enteric nervous system. This study aimed to verifying the 2,4-D effects on the myenteric neurons in duodenum of Wistar rats. Ten 60-day-old male Wistar rats (Rattus norvegicus) were divided in two groups: control group (C) that did not receive 2,4-D and experimental group (E) that received 5.0 mg of 2,4-D/kg for 15 days. At the end of experimental period, the animal were euthanized, the duodenum was collected and processed for NADPH-diaphorase histochemical analysis in order to expose the nitrergic myenteric neurons (NADPH-dp). In the light microscopy analysis, the whole-mount preparation obtained from duodenum of each animal were image-captured in 120 and 40 fields, for quantitative and morphometric analyses of myenteric neurons, respectively. The neuronal density was not affected when comparing the two groups, but an increase (p > 0.05) of 8.5% was observed in the cell body area of neurons in the E group. In conclusion, the ingestion of 2,4-D at a dosage of 5.0 mg/kg body weight for 15 days does not change the neuronal density, but promotes the hypertrophy of NADPH-dp myenteric neurons in duodenum of the rats of this study.

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Objectives. To compare maternal flow-mediated dilation (FMD) of the brachial artery and nitrite concentration between third trimester of pregnancy (3rdT) and postpartum (PP) period. Additionally, we will evaluate whether FMD correlates with nitrite concentration in both periods. Methods. Eligibility criteria was healthy women with singleton pregnancy, gestational age >28 weeks, nonsmokers, and no personal or family history of vascular disease. Each women was examined during 3rdT and between 8 and 12 weeks PP to evaluate FMD and nitrite concentration in whole blood. Women not examined in both periods were excluded. Values between both periods were compared using paired t tests. Correlation between FMD and nitrite was examined by Pearson correlation coefficient. Significance level set as p<0.05. Results. We invited 42 pregnant women. Among them, 35 were eligible and 7 of them were excluded for not attending the PP evaluation resulting in 28 participants analyzed. We found no significant change in FMD (10.39±5.57% vs. 8.42±4.21%; p=0.11; 3rdT vs. PP, respectively) and no significant change in nitrite concentration (257.41±122.95nmol/L vs. 237.16±90.01nmol/L; p=0.28). Baseline brachial artery diameter had a significant reduction (3.11±0.30 to 2.75±0.34mm; p<0.01). No significant correlation between FMD and nitrite during 3rdT (r=-0.13; p=0.50) or PP (r=0.14; p=0.48) was found. Conclusions. We did not observe significant changes in both FMD and nitrite concentration between third trimester and the PP period. FMD did not correlate with nitrite in both periods. More studies are needed to confirm our findings. © Informa Healthcare USA, Inc.

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Amphibians have melanin-containing cells in visceral organs that are similar to pigmentary cells from the epidermis. Both of them are derived from the ectodermal neural crest. Epidermal cells respond to α-melanocyte stimulating hormone (α-MSH), which is associated to the dispersion of melanin granules within melanocytes. Therefore, our aim was to test whether a non-degradable analogue of the α-MSH changes the superficial colouration of organs of Eupemphix nattereri. The hormone rapidly increases (within 12 hours) the colouration on the surface of the pericardium, heart, testes, nerves of the lumbar plexus, and lumbosacral parietal peritoneum. Colouration increased late (after 24 hours) in the kidneys and mesentery following hormone administration. However, this hormone did not change colouration of intestine, rectum and lungs. Our findings could be explained by the similarities between epidermal and visceral melanocytes, since both cells have a common embryonic origin. Furthermore, the increase in visceral colouration may be related to the dispersion of melanosomes within melanocytes, which causes the darkening of organs. Our results demonstrate for the first time that the visceral colouration is responsive, thereby altering the internal pattern of organs' colouration in anurans. © 2013 Copyright 2013 Unione Zoologica Italiana.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)