Distinct adaptation patterns between grip dynamics and arm kinematics when the body is upside-down.

In humans, practically all movements are learnt and performed in a constant gravitational field. Yet, studies on arm movements and object manipulation in parabolic flight have highlighted very fast sensorimotor adaptations to altered gravity environments. Here, we wondered if the motor adjustments observed in those altered gravity environments could also be observed on Earth in a situation where the body is upside-down. To address this question, we asked participants to perform rhythmic arm movements in two different body postures (right-side-up and upside-down) while holding an object in precision grip. Analyses of grip-load force coordination and of movement kinematics revealed distinct adaptation patterns between grip and arm control. Grip force and load force were tightly synchronized from the first movements performed in upside-down posture, reflecting a malleable allocentric grip control. In contrast, velocity profiles showed a more progressive adaptation to the upside-down posture and reflected an egocentric planning of arm kinematics. In addition to suggesting distinct mechanisms between grip dynamics and arm kinematics for adaptation to novel contexts, these results also suggest the existence of general mechanisms underlying gravity-dependent motor adaptation that can be used for fast sensorimotor coordination across different postures on Earth and, incidentally, across different gravitational conditions in parabolic flights, in human centrifuges, or in Space.NEW & NOTEWORTHY During rhythmic arm movements performed in an upside-down posture, grip control adapted very quickly, but kinematics adaptation was more progressive. Our results suggest that grip control and movement kinematics planning might operate in different reference frames. Moreover, by comparing our results with previous results from parabolic flight studies, we propose that a common mechanism underlies adaptation to unfamiliar body postures and adaptation to altered gravity.

Acamprosate and diazepam differentially modulate alcohol-induced behavioural and cortical alterations in rats following chronic inhalation of ethanol vapour.

The effects of Acamprosate (the calcium salt of an acetylated form of homotaurine) and the benzodiazepine-receptor agonist Diazepam, were investigated on the alcohol-induced behavioural preference towards alcohol following chronic alcoholization by inhalation. We also examined the effects of Acamprosate and Diazepam on the blood alcohol level (BAL) and on the cortical microvascular network. Acamprosate (50, 100, 200 and 400 mg/kg daily per os during the alcoholization period) did not significantly reduce either BAL or alcohol-induced cortical hypervascularization. Increasing dosages of Acamprosate (i.e. 50, 100, and 200 mg/kg/day), however, progressively reduced preference for alcohol as expressed in a free choice beverage procedure, whereas 400 mg/kg/day of Acamprosate immediately stopped this behaviour. Acamprosate (50 mg/kg/day) also reduced the spontaneous activity of rats during the withdrawal syndrome. By contrast, Diazepam (5 mg/kg) induced inversion in the animals' choice (i.e. increased water consumption versus decreased alcohol intake) during the same experimental procedure, and potentiated the alcohol-induced hypermotility of the animals during the withdrawal syndrome without altering cortical hypervascularization. Taken together, our data provide evidence that both substances exert dose-dependent effects on preference towards alcohol, but display opposite profiles on spontaneous motor activity during the withdrawal phase without any modification of brain microvascularization or blood alcohol levels.

Naftidrofuryl in the treatment of subacute stroke.

In a placebo-controlled, double-blind study, 82 patients in the subacute stage of a disabling stroke were studied to assess the effect on clinical improvement of 600 mg naftidrofuryl against placebo. Forty-two patients were treated with the drug and 40 with placebo, in each case administered for 60 days. All patients received 100 mg aspirin and 300 mg dipyridamole daily and entered a similar program of rehabilitation therapy. At the start and the end of the study, the motor functions of the upper and lower limbs, the ability to walk and to perform daily activities, the comprehension and expression of speech, and the mental progress were assessed with quantitative linear scales. In the group treated with active drug, a greater overall tendency of improvement was observed, reaching statistically significant levels for walking and activities of daily life when compared to placebo-treated patients. Overall improvement was negatively influenced by advancing age, but the statistically significant effect of treatment on walking and daily activities was not interfered with by age. Right-sided lesions showed better improvement under active drug than left-sided lesions. This may be due to a correctional effect of naftidrofuryl on hemispatial neglect.

In vitro fertilization and embryo transfer as related to endogenous luteinizing hormone rise or human chorionic gonadotropin administration.

After ovarian stimulation with clomiphene citrate combined with human menopausal gonadotropin for in vitro fertilization, the appearance of a spontaneous luteinizing hormone (LH) surge before fulfillment of the minimal criteria of follicular maturity (at least one follicle greater than 19 mm and serum estradiol [E2] greater than 400 pg/ml/follicle greater than 17 mm) is associated with reduced pregnancy rates. In these cases, follicles are smaller and serum E2 values are lower at the time of the LH surge. Oocyte recovery rate is reduced, embryonic anucleate fragments are more frequently observed, and the level of luteal progesterone on day 4 after oocyte retrieval is lower. Hyperandrogenic patients are more prone to display such premature spontaneous LH surge. We concluded that in case of an untimely LH rise, laparoscopy for oocyte retrieval should be cancelled.