124 resultados para Muscle tissue


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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 IIb 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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Um experimento foi conduzido com o objetivo de verificar os efeitos de diferentes relações flúor:fosforo na alimentação sobre o desempenho de frangos de corte. Foram utilizados 1.000 pintos de corte de 1 dia distribuídos em um delineamento inteiramente casualizado, com quatro tratamentos e cinco repetições de 50 aves por boxe. Os tratamentos consistiram de quatro fontes de fósforo com relações flúor:fósforo de 1:40, 1:60, 1:80 e 1:100. O experimento foi dividido em três fases experimentais: 1 a 21, 22 a 42 e 43 a 49 dias de idade. em cada fase, avaliou-se o consumo de ração, o ganho de peso e a conversão alimentar. Ao final do experimento, foram abatidas duas aves de cada repetição para coleta da tíbia e de músculos do peito para análise das concentrações de flúor, cálcio, fósforo e magnésio desses tecidos. As relações flúor:fósforo avaliadas não afetaram o desempenho dos frangos de corte. A deposição óssea de flúor é proporcional à sua concentração na dieta, no entanto, a elevação dos níveis de flúor da dieta não influencia sua deposição nos músculos.

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Com o objetivo de estudar o efeito da restrição alimentar sobre as características da carcaça de caprinos leiteiros, realizou-se um experimento utilizando 27 cabritos castrados da raça Saanen. Os animais (PV inicial de 20 kg) foram distribuídos nos tratamentos alimentação à vontade e 30 e 60% de restrição, sendo abatidos aos 35 kg de PV. Foram avaliados o rendimento comercial e biológico, os cortes comerciais, a área de olho-de-lombo e a composição tecidual da perna. O rendimento biológico não foi afetado pela restrição alimentar, mas o comercial diminuiu com o aumento da restrição. A elevação no nível de restrição alimentar promoveu diminuição do lombo e da 6ª a 13ª costelas e aumento da paleta e do pescoço, proporcionalmente à meia-carcaça. A proporção de ossos aumentou e a de gordura total diminuiu com o aumento da restrição. O tecido muscular não foi afetado pela restrição. A restrição alimentar de até 30% não prejudicou a qualidade da carcaça de caprinos leiteiros.

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The acute toxicity of 2,4-dichlorophenoxyacetic acid (2,4-D), a herbicide, was studied in chicks dosed with 100, 300, 500, or 600 mg 2,4-D/kg BW, by the oral route. Clinical, laboratory, and histopathological methods were used as indicators of toxicity. After acute exposure, the herbicide decreased motor activity and induced muscular weakness and motor incoordination; decreased weight gain; increased serum creatine kinase (CK) and alkaline phosphatase (AP) activities and serum uric acid (UA), creatinine (CR), and total proteins (TP) levels; and did not change serum aspartate aminotransferase (AST) or alanine aminotransferase (ALT) activities. These changes were time-and dose-dependent and reversible. The LD50 (lethal dose 50%) calculated for oral 2,4-D in chicks was 420 mg/kg BW (385 to 483). Chromatographic analysis of the serum of the intoxicated chicks showed the presence of the herbicide; the amount found was dose-and time-dependent, increasing from 2 to 8 h after exposure and decreasing afterwards. Histopathological post-mortem studies conducted on intoxicated chicks showed hepatic (vacuolar degeneration of the hepatocytes), renal (tubular nephrosis), and intestinal (hemorragic) lesions. Taken together, the observed alterations mainly reflected kidney and muscle tissue damage, although hepatic toxicity may also have occurred after acute 2,4-D intoxication.

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Avaliaram-se o desempenho e a qualidade da carne de frangos de corte alimentados com diferentes níveis de sorgo, do cultivar SAARA, com 0,49g/kg de tanino, em substituição ao milho. Os 2600 pintos sexados de um dia de idade, da linhagem Ross 308, foram distribuídos em delineamento inteiramente ao acaso, com esquema fatorial 5×2 (cinco níveis de sorgo - 0, 25, 50, 75 e 100% e dois sexos), e quatro repetições de 65 aves por unidade experimental. Não houve efeito (P>0,05) da substituição do milho pelo sorgo sobre as características de desempenho, de rendimentos de carcaça, carne de peito e pernas, de composição química e sensoriais. O pH observado nas carnes de peito e pernas foi maior para os machos (P<0,05), e houve diminuição do pH à medida que se aumentaram os níveis de substituição. Os machos apresentaram os maiores valores nas medidas de comprimento, largura e espessura do filé. Na carne do peito dos machos, ocorreu maior perda de peso por cozimento e força de cisalhamento (P<0,05). Observou-se diminuição (P<0,05) dos valores de a (vermelho) e b (amarelo) e aumento de L (luminosidade) à medida que aumentaram os níveis de substituição.

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The activities of the enzymes aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LD), creatine kinase (CK), amylase (AMS) and angiotensin converting enzyme (ACE) have been used to assess the toxic effects of xenobiotics that have hypoglycaemic action in hepatic, pancreatic, renal and muscle tissue. Using a validated experimental model of diabetes mellitus in rats, we ascertained whether this syndrome itself affected the serum activities of these enzymes over a 53-day period. Levels of hepatic enzymes AST, ALT and ALP were higher in the streptozotocin (STZ)diabetic rats (group D), but were controlled by insulin therapy (group DI). AMS was reduced in group D and unchanged in group DI rats. Proteinuria was detected 1 day after STZ administation and partially controlled by insulin (group DI); its early presence in group D rats, and the lack of any change in serum ACE in this group, indicates that proteinuria is the better marker for microangiopathy. Microscopic examination of liver, kidney, heart and skeletal muscles (soleus and extensor digitorum longus) revealed various alterations in group D rat tissues, which were less pronounced in group DI. The liver, pancreas and kidney tissue-damage was consistent with the altered serum levels of AST, ALT, ALP and AMS and proteinuria. We conclude that: (i) rigorous control is required when these serum-enzyme levels are used as indicators of tissue toxicity in experimental diabetes, and (ii) LD, CK and bilirubin serum levels, which are unaffected by diabetes, can be used when testing effects of xenobiotics on tissues.

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Skeletal muscle fibers areas, the weight of body, carcass and muscle, the gastric content and the length of intestines and caecum of Norfolk rabbit from neonate to 26th week were measured. Types of fibers and areas were studied in -70-degrees-C frozen blocks of flexor carpo radialis muscle. Some sections were stained with Haematoxylin and Eosin and others were submitted to SDH, NADH-TR and m-ATPase, followed by acid and alkali preincubations. All parameters revealed a high degree of correlation. Carcass weight/body weight ratio reached 55,1% at 10th week. From neonate to 26th week, the areas of SO, FOG and FG muscle fibers increased of x9.1, x12.4 and x22.2. While SO and FOG fibers tend to stabilize their growth at 10th week, FG fibers were active at this age. Due to early stabilization of SO and FOG fibers growth, the additional increase in muscle tissue in attributed mainly to hypertrophy of FG fibers.

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The aim of this work was to evaluate the morphological, growth characteristics of skeletal muscle tissue III Pirarucu (Arapaima gigas) using alevins (50 days old) and juveniles (1 year old). Muscle samples were collected from dorsal, lateral cranial mid lateral caudal regions, and then frozen in liquid nitrogen. Histological frozen sections (10 [mu]m) were stained with HE and Gomori Trichrome for morphological analysis, and NADH-TR to evaluate muscle fiber oxidative metabolism. Morphometric analysis samples were obtained from dorsal and lateral cranial regions, and the smallest-diameter white fibers were measured. White dorsal muscle was thicker, and two muscle fiber compartments were identified in the lateral cranial region: red (superficial) mid white (deep) muscle. Hyperplasia muscle growth predominated in alevins mid hypertrophy in juveniles.

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The acute, subchronic and chronic toxicities of 2,4- dichlorophenoxyacetic acid (2,4-D) were studied in rats. Animals were exposed acutely (600 mg/kg), subchronically (200 ppm for 30 d) and chronically (200 ppm for 180 d) to 2,4-D by the oral route. Clinical, laboratory and histopathological methods were used as indicators of toxicity. After acute exposure, the herbicide decreased locomotor activity and induced ataxia, sedation, muscular weakness (mainly of the hind quarters) and gasping for breath; increased aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), alkaline phosphatase (AP), amylase activities and creatinine levels; decreased total protein (TP) and glucose levels; and increased hematocrit values. Subchronic and chronic 2,4-D exposures did not induce overt clinical signs or symptoms of intoxication. However, subchronic herbicide exposure increased AST activity and albumin and hematocrit values, and chronic exposure increased AST, AP and LDH activities, decreased amylase and glucose levels, but did not change hematocrit values. Chromatographic analysis of the serum of chronically exposed rats showed the presence of the herbicide; the amount found (3.76 ± 1.16 mg/ml) suggested the absence of 2,4-D accumulation within the body. Although macroscopic or histopathological lesions were not observed in acutely, subchronically or chronically 2,4-D exposed rats, the laboratory data obtained suggest tissue injuries after dosing, since the results are considered early indicators of primarily hepatic and muscle tissue damage.

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Lys49 snake-venom phospholipase A2 (PLA2) homologues are highly myotoxic proteins which, although lacking catalytic activity, possess the ability to disrupt biological membranes, inducing significant muscle-tissue loss and permanent disability in severely envenomed patients. Since the structural basis for their toxic activity is still only partially understood, the structure of myotoxin II, a monomeric Lys49 PLA2 homologue from Atropoides nummifer, has been determined at 2.08 Å resolution and the anion-binding site has been characterized. © 2006 International Union of Crystallography. All rights reserved.

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In the present study, we evaluated three techniques, mouse bioassay, histopathology, and polymerase chain reaction (PCR) to detect Toxoplasma gondii infection in tissues from experimentally infected pigs. Twelve mixed breed pigs, seronegative for T. gondii using an indirect immunofluorescent antibody test (IFAT), were used. Ten pigs were infected with 4 × 104 VEG strain oocysts, and two were maintained as uninfected controls. Animals were killed 60 days pos infection. Muscle (heart, tongue, diaphragm, and masseter) and brain samples were collected to investigate the presence of T. gondii tissue cysts by the different assay methods. For the bioassay, samples of brain (50 g) and pool of muscle samples (12.5 g of tongue, masseter, diaphragm, and heart) were used. PCR was performed using Tox4 and Tox5 primers which amplified a 529 bp fragment. The DNA extraction and PCR were performed three times, and all tissue samples were tested individually (brain, tongue, masseter, diaphragm, and heart). For histopathology, fragments of tissues were fixed in 10% of buffered formal saline and stained with HE. Histopathological results were all negative. PCR showed 25/150 (16.6%) positive samples, being 17/120 (14.1%) and 8/30 (26.6%) from muscle, and brain tissues, respectively. Tissue cysts of T. gondii were identified by mouse bioassay in 54/98 (55.1%) samples, being 31/48 (64.6%) from muscle samples, and 23/50 (46.0%) from brain samples. Toxoplasma gondii isolation in muscle samples by mouse bioassay was higher than in PCR (P < 0.01). Results indicate that DNA from pig tissues interfered with 529-bp-PCR sensitivity, and mouse bioassay was better than PCR in detecting T. gondii in tissues from pigs. © 2006 Elsevier Inc. All rights reserved.