32 research outputs found

    Antiarrhythmic and antioxidant activity of novel pyrrolidin-2-one derivatives with adrenolytic properties

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    A series of novel pyrrolidin-2-one derivatives (17 compounds) with adrenolytic properties was evaluated for antiarrhythmic, electrocardiographic and antioxidant activity. Some of them displayed antiarrhythmic activity in barium chloride-induced arrhythmia and in the rat coronary artery ligation-reperfusion model, and slightly decreased the heart rate, prolonged P–Q, Q–T intervals and QRS complex. Among them, compound EP-40 (1-[2-hydroxy-3-[4-[(2-hydroxyphenyl)piperazin-1-yl]propyl]pyrrolidin-2-one showed excellent antiarrhythmic activity. This compound had significantly antioxidant effect, too. The present results suggest that the antiarrhythmic effect of compound EP-40 is related to their adrenolytic and antioxidant properties. A biological activity prediction using the PASS software shows that compound EP-35 and EP-40 can be characterized by antiischemic activity; whereas, compound EP-68, EP-70, EP-71 could be good tachycardia agents

    Functional Changes in Muscle Afferent Neurones in an Osteoarthritis Model: Implications for Impaired Proprioceptive Performance

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    Impaired proprioceptive performance is a significant clinical issue for many who suffer osteoarthritis (OA) and is a risk factor for falls and other liabilities. This study was designed to evaluate weight-bearing distribution in a rat model of OA and to determine whether changes also occur in muscle afferent neurones.Intracellular recordings were made in functionally identified dorsal root ganglion neurones in acute electrophysiological experiments on the anaesthetized animal following measurements of hind limb weight bearing in the incapacitance test. OA rats but not naïve control rats stood with less weight on the ipsilateral hind leg (P = 0.02). In the acute electrophysiological experiments that followed weight bearing measurements, action potentials (AP) elicited by electrical stimulation of the dorsal roots differed in OA rats, including longer AP duration (P = 0.006), slower rise time (P = 0.001) and slower maximum rising rate (P = 0.03). Depolarizing intracellular current injection elicited more APs in models than in naïve muscle afferent neurones (P = 0.01) indicating greater excitability. Axonal conduction velocity in model animals was slower (P = 0.04).The present study demonstrates changes in hind limb stance accompanied by changes in the functional properties of muscle afferent neurones in this derangement model of OA. This may provide a possible avenue to explore mechanisms underlying the impaired proprioceptive performance and perhaps other sensory disorders in people with OA

    Observing many researchers using the same data and hypothesis reveals a hidden universe of uncertainty

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    This study explores how researchers’ analytical choices affect the reliability of scientific findings. Most discussions of reliability problems in science focus on systematic biases. We broaden the lens to emphasize the idiosyncrasy of conscious and unconscious decisions that researchers make during data analysis. We coordinated 161 researchers in 73 research teams and observed their research decisions as they used the same data to independently test the same prominent social science hypothesis: that greater immigration reduces support for social policies among the public. In this typical case of social science research, research teams reported both widely diverging numerical findings and substantive conclusions despite identical start conditions. Researchers’ expertise, prior beliefs, and expectations barely predict the wide variation in research outcomes. More than 95% of the total variance in numerical results remains unexplained even after qualitative coding of all identifiable decisions in each team’s workflow. This reveals a universe of uncertainty that remains hidden when considering a single study in isolation. The idiosyncratic nature of how researchers’ results and conclusions varied is a previously underappreciated explanation for why many scientific hypotheses remain contested. These results call for greater epistemic humility and clarity in reporting scientific findings

    Propriocepção de joelho em jovens e idosas praticantes de exercícios físicos Knee proprioception in physically active young and elderly women

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    A propriocepção é um mecanismo neuromuscular que descreve informações neurais originadas nas articulações, músculos e tendões. Este estudo verificou a propriocepção de joelho em jovens e idosas praticantes de exercícios físicos. Participaram do estudo 44 mulheres - 22 idosas (média de idade 69,4 anos) e 22 jovens, idade média 22,5). A propriocepção foi avaliada pelo senso de posição articular, sendo a participante solicitada a reposicionar o membro inferior dominante previamente estendido ou flexionado pelo avaliador. Os ângulos de flexão e extensão do joelho foram sorteado, utilizando-se nos testes um goniômetro fixo à perna da participante. Considerou-se como variável o valor absoluto do erro, isto é, a diferença em graus entre o ângulo proposto e o ângulo reproduzido pela avaliada. Os dados foram tratados estatisticamente, com nível de significância de p<0,05. A média de erro das idosas foi 6,75±3,01º e, das jovens, 5,73±4,24º, não havendo diferença estatisticamente significativa (p=0,249) entre os grupos. Concluiu-se que, apesar da propriocepção sofrer um declínio com a idade, possivelmente devido à prática de exercícios físicos o grupo de idosas apresentou resultados similares ao das jovens, sugerindo que a prática de exercícios físicos constitui uma estratégia benéfica para atenuar o declínio provocado pelo envelhecimento.<br>Proprioception is a neuromuscular mechanism that describes neural information originating from the joints, muscles and tendons. This study aimed at verifying proprioception of the knee in young and elderly women with regular physical activity. Subjects were 44 women - 22 elderly, mean age 69.4 years old, and 22 young women, mean age 22.5 years old. Proprioception was assessed by the sense of joint position, the subject being asked to reposition the dominant leg previously flexed or extended by the examiner. Flexion and extension angles were randomized, and measured by means of a goniometer attached to the subject's leg. The variable considered was the absolute error value, that is, the difference between the angle proposed and the angle shown by the subject. Data were statistically analysed and significance level set at p<0.05. The elderly group mean error was 6.75±3.01º, and the young ladies', 5.73±4.24°; no significant difference (p=0.249) was found between the groups. Hence, although proprioception is known to decline with age, the elderly group showed results similar to the youths, possibly due to the practice of physical exercise, which suggests that the latter constitute a beneficial strategy to lessen the aging natural decline
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