41 research outputs found

    Misperceptions in the Trajectories of Objects undergoing Curvilinear Motion

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    Trajectory perception is crucial in scene understanding and action. A variety of trajectory misperceptions have been reported in the literature. In this study, we quantify earlier observations that reported distortions in the perceived shape of bilinear trajectories and in the perceived positions of their deviation. Our results show that bilinear trajectories with deviation angles smaller than 90 deg are perceived smoothed while those with deviation angles larger than 90 degrees are perceived sharpened. The sharpening effect is weaker in magnitude than the smoothing effect. We also found a correlation between the distortion of perceived trajectories and the perceived shift of their deviation point. Finally, using a dual-task paradigm, we found that reducing attentional resources allocated to the moving target causes an increase in the perceived shift of the deviation point of the trajectory. We interpret these results in the context of interactions between motion and position systems

    Primary biliary cirrhosis

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    Primary biliary cirrhosis (PBC) is an immune-mediated chronic cholestatic liver disease with a slowly progressive course. Without treatment, most patients eventually develop fibrosis and cirrhosis of the liver and may need liver transplantation in the late stage of disease. PBC primarily affects women (female preponderance 9–10:1) with a prevalence of up to 1 in 1,000 women over 40 years of age. Common symptoms of the disease are fatigue and pruritus, but most patients are asymptomatic at first presentation. The diagnosis is based on sustained elevation of serum markers of cholestasis, i.e., alkaline phosphatase and gamma-glutamyl transferase, and the presence of serum antimitochondrial antibodies directed against the E2 subunit of the pyruvate dehydrogenase complex. Histologically, PBC is characterized by florid bile duct lesions with damage to biliary epithelial cells, an often dense portal inflammatory infiltrate and progressive loss of small intrahepatic bile ducts. Although the insight into pathogenetic aspects of PBC has grown enormously during the recent decade and numerous genetic, environmental, and infectious factors have been disclosed which may contribute to the development of PBC, the precise pathogenesis remains enigmatic. Ursodeoxycholic acid (UDCA) is currently the only FDA-approved medical treatment for PBC. When administered at adequate doses of 13–15 mg/kg/day, up to two out of three patients with PBC may have a normal life expectancy without additional therapeutic measures. The mode of action of UDCA is still under discussion, but stimulation of impaired hepatocellular and cholangiocellular secretion, detoxification of bile, and antiapoptotic effects may represent key mechanisms. One out of three patients does not adequately respond to UDCA therapy and may need additional medical therapy and/or liver transplantation. This review summarizes current knowledge on the clinical, diagnostic, pathogenetic, and therapeutic aspects of PBC

    Hepatic enzymes' level during chronic use of anticonvulsant drugs Dosagens de enzimas hepáticas em pacientes em uso crônico de drogas antiepiléticas

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    We studied retrospectively 894 adult epileptic patients treated during the period from 1983 to 1992. Hepatic enzymes abnormal values were seen in 49%(n=438). In 22.3%(n=200), at least 2 enzyme levels in different moments were altered. They were divided in three groups: GI with alterations at transaminases (3%, n=6), GII with alterations at GGT and AP enzymes (72%,n=144) and GIII with alterations in both groups (25%, n=50). No patient developed clinical symptoms of liver disease. The increase of gamma-glutamil-transferase (GGT) and alkaline phosphatase (AP) levels is frequent and not necessarily pathological. Slight increase of transaminases can occur with no clinical correlation. The routine screening of hepatic enzymes level during the chronic use of anticonvulsivant drugs in adults has a questionable value.<br>Oitocentos e noventa e quatro pacientes epiléticos adultos tratados no período de 1983 a 1992 foram estudados retrospectivamente. Valores anormais de enzimas hepáticas foram detectados em 49% (n=438) dos casos. Em 200 pacientes (22,3%), ao menos duas dosagens obtidas em momentos diferentes estavam alteradas. Estes últimos foram divididos em 3 grupos: GI, com alterações de transaminases (3%, n=6); GII com alterações de gama-glutamil-transferase (GGT) e fosfatase alcalina (AP) (72%, n=144) e GIII com alterações nos dois grupos de enzimas (25%, n=50). Nenhum paciente desenvolveu sinais ou sintomas de doença hepática. O aumento de GGT e AP em pacientes em uso de drogas antiepiléticas é frequente e pode não ter significado patológico. Pequenos aumentos de transaminases também podem ocorrer sem correlação clínica
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