958 resultados para Cerebral blood flow


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Gastrointestinal problems are common, especially in endurance athletes, and often impair performance or subsequent recovery. Generally, studies suggest that 30-50 % of athletes experience such complaints. Most gastrointestinal symptoms during exercise are mild and of no risk to health, but hemorrhagic gastritis, hematochezia, and ischemic bowel can present serious medical challenges. Three main causes of gastrointestinal symptoms have been identified, and these are either physiological, mechanical, or nutritional in nature. During intense exercise, and especially when hypohydrated, mesenteric blood flow is reduced; this is believed to be one of the main contributors to the development of gastrointestinal symptoms. Reduced splanchnic perfusion could result in compromised gut permeability in athletes. However, although evidence exists that this might occur, this has not yet been definitively linked to the prevalence of gastrointestinal symptoms. Nutritional training and appropriate nutrition choices can reduce the risk of gastrointestinal discomfort during exercise by ensuring rapid gastric emptying and the absorption of water and nutrients, and by maintaining adequate perfusion of the splanchnic vasculature. A number of nutritional manipulations have been proposed to minimize gastrointestinal symptoms, including the use of multiple transportable carbohydrates, and potentially the use of nutrients that stimulate the production of nitric oxide in the intestine and thereby improve splanchnic perfusion. However, at this stage, evidence for beneficial effects of such interventions is lacking, and more research needs to be conducted to obtain a better understanding of the etiology of the problems and to improve the recommendations to athletes.

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Several reconstructive methods of the alveolar ridge have been reported to make possible future rehabilitations with implants. Many of these methods come from studies done in animals, mainly rats. With this clinical practice based on scientific evidence, any experimental procedure that can be undertaken in real life is fundamental. Thus, any research that emulates as closely as possible those techniques used in humans are important. This study describes the modification of the technique for block bone graft fixation (onlay) in rats using the lag screw-type technique, normally used in clinical procedures for grafts in humans. The conclusion was that the execution of the described procedures minimizes interference of blood flow in the area because of the maintenance of the muscle insertion in the buckle aspect of the most anterior region of the mandible, providing better stability to the graft and better contact interface of the graft and receptor bed.

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

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The control of blood flow during exercise involves different mechanisms, one of which is the activation of the renin-angiotensin system, which contributes to exercise-induced blood flow redistribution. Moreover, although angiotensin II (Ang II) is considered a potent venoconstrictor agonist, little is known about its effects on the venous bed during exercise. Therefore, the present study aimed to assess the Ang II responses in thefemoral vein taken from sedentary and trained rats at rest or subjected to a single bout of exercise immediately before organ bath experiments. Isolated preparations of femoral veins taken from resting-sedentary, exercised-sedentary, resting-trained and exercised-trained animals were studied in an organ bath. In parallel, the mRNA expression of prepro-endothelin-1 (ppET-1), as well as the ETA and ETB receptors, was quantified by real-time PCR in this tissue. The results show that, in the presence of L-NAME, Ang II responses in resting-sedentary animals were higher compared to the other groups. However, this difference disappeared after co-treatment with indomethacin, BQ-123 or BQ-788. Moreover, exercise reduced ppET-1 mRNA expression. These reductions in mRNA expression were more evident in resting-trained animals. In conclusion, either acute or repeated exercise adapts the rat femoral veins, thereby reducing the Ang II responses. This adaptation is masked by the action of locally produced nitric oxide and involves, at least partially, the ETB- mediated release of vasodilator prostanoids. Reductions in endothelin-1 production may also be involved in these exercise-induced modifications of Ang II responses in the femoral vein.

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Doppler ultrasound enables the assessment of blood flow in real time and has been widely used to aid in pregnancy diagnosis and monitoring in dogs and cats. This technique has a diferencial when compared with the B-mode ultrasound, as it allows the evaluation of vascular hemodynamic characteristics, while the two-dimensional ultrasound allows the diagnosis of pregnancy and fetal viability. Thus, the objective of this review is to describe how circulation is characterized in the uterine and fetal arteries in bitches during pregnancy using Doppler ultrasonography.

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An equine, American Troter, female, 5 years of age, was referred to the Diagnostic Imaging Sector at the Veterinary Hospital of the FMVZ, Unesp, Botucatu Campus, with suspected jugular thrombosis. Ultrasonographic findings were heterogeneous tissue at the lumen of the right jugular vein with blockage of its diameter and collateral blood flow formation.

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Portal hypertension (PH) is the pathological increase in portal vein pressure above normal limits. Two variables control the pressure in the portal system: the resistance to blood flow and blood flow volume in the portal system. If one these variables changes, PH may develop. Classification: Pre-hepatic (e. g. compression of the portal vein), intrahepatic (e. g. chronic hepatitis and cirrhosis) or post-hepatic (e. g. right heart failure). The invasive methods (intravenous catheter) were replaced by an indirect method of diagnosis: Doppler Ultrasound. This technique does not measure portal pressure, but indirectly allows the diagnosis of PH. Average speed of portal flow decrease (<10 cm/s) and hepatofugal flow have been reported in cirrhotic dogs with PH. Currently, the focus of the ultrasound is the detection of acquired collateral portal circulation (ACPC), closely correlated with hepatic encephalopathy. The characterization of these vessels is essential to differentiate them from congenital shunts. They are usually multiple vessels, small and tortuous, with turbulent flow, near to the kidneys, and/or a single and larger vessel, draining into the left renal vein (dilated gonadal vein). Gastric, esophageal and mesenteric varices may occur. After identifying the PH, it is important to determine its origin in order to treat the underlying disease. B-Mode Ultrasound and Doppler are the best choices in cases of suspected PH, because they may recognize not just the hypertension, but also its complications and origin.

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Portosystemic shunt, an hepatobiliary anomaly, much common in dogs and less frequent in cats, can be detected by several diagnostic methods. Among them, the one which stands out is ultrasonography due to its numerous advantages: noninvasive, quick, accessible, relatively low cost and provides useful information relating to the other systems, apart from being a highly sensitive method. Portosystemic shunt diagnosis using ultrasonography becomes highly sensitive when associated with B-mode, color Doppler and pulsed Doppler. A bibliographic survey about portosystemic shunt ultrasonographic diagnosis was carried out, and the main ultrasonographic signals were: decreased hepatic size, difficulty in blood vessels visualization, presence of an anomalous vessel, tortuous with turbulent flow and, finally, increased portal blood flow velocity near the shunting vessel

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The Doppler ultrasound allows the assessment of blood flow and the differentiate vessels according to each spectral pattern, location and organ that irrigate, helping the examinations and disease diagnosis. The main methods used are Pulsed Doppler, Color Doppler and Power Doppler. In Brazil veterinary medicine, it shows progress since 1990, but its use is limited by the equipment high cost, the need for operator experience and patient cooperation. There are studies in obstetrics and reproduction of dogs and cats, such as evaluation of the testicular vasculature, including the use of contrast material, and attempts to evaluate prostate in healthy dogs or pathological conditions (cancer and testicular torsion , orchitis and benign prostatic hyperplasia; estrous cycle monitoring, evaluation of irrigation in follicles and corpus luteum, uterus and breasts (mammary tumors) in bitches; monitoring pregnancy from the assessment of maternal, fetal and placental hemodynamics, both in dogs as in cats, and aspirations for early detection of pregnancy in dogs. However, new studies are still required, given the lack of these species, especially cats

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Legg-Calvé-Perthes disease is a non-inflammatory aseptic necrosis of the head of the femur that is found in both young animals and humans before the gap in the femur head closes. In the fields of both human and veterinary medicine the cause of this condition is not known for certain. Various factors have been put forward in the literature as being responsible for the incidence of this condition such as: abnormalities in coagulation, changes in blood flow in the arteries, a septic obstruction in the draining of the epiphysis or the upper parts of the femur, trauma, growth cycle, hyperactivity in a child, genetic influences and dietary factors. Case histories in dogs show that the first stages of the condition progress slowly but that limping or putting weight on the limb worsens at 6 to 8 weeks. Some owners talk about a sharp onset in clinical lameness. Other clinical symptoms may include irritability, loss of appetite and knawing at the hair surrounding the affected hip. In the course of physical examination manipulating the hip joint will cause pain to the animal. The advanced stages of the disease may result in restricted amplitude of movement, muscular atrophy and fracturing. In humans the clinical signs are similar, although progression of the disease is slower so that it can be diagnosed at an earlier stage. In veterinary medicine the diagnosis is, in the main, based on case history, clinical symptoms, physical examination and certain related procedures such as radiography. The various diagnoses include physical trauma and dislocation of the medial patella. In human medicine many people have been correctly diagnosed. Whatsmore, there is a range of related procedures that are virtually not available to veterinary medicine such as magnetic nuclear resonance, that show up necroses with great clarity before radiography and cintilography do, and is considered... (Complete abstract click electronic access below)