No abstract

The data indicate that fatigue perceived by MS patients is associated with measures of fatigability. This observation helps in the understanding of mechanisms underlying the increased levels of fatigue perceived by MS patients. These data also emphasize that for comparison of fatigue-related parameters between groups, correction for individual maximal force is essential.

A Fitts' task was used to examine whether the large movement asymmetry in subjects with spastic hemiparesis can be reduced or eliminated when both limbs are required to perform functionally equivalent tasks. Furthermore, it was determined whether any such benefit was expressed as mutual accommodation, or whether one hand "slaves" the other. Finally, the effect of increased task constraints on the magnitude of the asymmetry was considered. A group of ten students served as controls. Subjects had to grasp small balls and subsequently place them into holes. As expected, large total response time differences were present between the hands of the hemiparetic subjects in the unimanual conditions. However, 92% of the difference between hands was eliminated in the bimanual conditions. It is argued that the observed temporal invariance, or time locking, between hands in the bimanual conditions might be facilitated through the activity of bilateral controls exerted from each hemisphere and neural crosstalk at different levels of the central nervous system. Still, an asymmetric tendency remained in the bimanual conditions: a tendency existed for the impaired hand to reach the "target" later in time compared with the dominant hand. This tendency was enlarged as the asymmetry in task demands for the two limbs increased.

Volatile agent-induced hypotension may contribute to anaesthetic-related morbidity and mortality in horses. Dobutamine is commonly used to support arterial blood pressure (ABP) but little is known about its cardiovascular effects under clinical conditions. The aim of this clinical study was to elucidate the relationship between cardiovascular function and dobutamine infusion in isoflurane-anaesthetized horses. Forty-four horses anaesthetized for a variety of surgical procedures were studied. Premedication with acepromazine, methadone and detomidine was followed by induction of anaesthesia with ketamine and midazolam. Anaesthesia was maintained with isoflurane vaporized in oxygen. Routine anaesthetic monitoring was applied and cardiac output was measured by lithium dilution. Dobutamine was infused to maintain mean ABP above 70 mmHg. The relationship between dobutamine infusion rate, heart rate (HR), ABP and cardiac index was investigated immediately prior to (T(0)) and 15 min (T(1)) after dobutamine infusion started, followed at 30 min intervals (T(2), etc.). Arterial blood pressure increased significantly after dobutamine infusion started, HR and cardiac index increased significantly only with dobutamine infusion in combination with surgical stimulus. Although isoflurane decreases blood pressure mainly by vasodilation, dobutamine is an effective treatment for hypotension under clinical conditions in isoflurane-anaesthetized horses. The effect of dobutamine is not directly proportional to dose and surgical stimulus probably contributes to the cardiovascular improvement.