This study was designed to investigate the change of postural control while repeatedly imposing the horizontal floor vibration in upright stance. A vibration table mounted with a force platform was vibrated sinusoidaly in anteroposterior direction under the condition of 2.5 cm amplitude and 0.5 Hz frequency. Ten female subjects, aged from 18 to 21 years, were equally divided into O-group and C-group. The subjects maintained the standing posture on the vibration table, for one minute with open and closed eyes in both groups in the first trial, for two minutes with open eyes in O-group and with closed eyes in C-group in the 2 nd to 11 th trials, and for one minute with closed eyes in O-group and open eyes in C-group in the 12th trial. The fluctuation of the center of foot pressure (CFP) in anteroposterior direction and EMGs of m. tibialis anterior and m. gastrocnemius were analyzed. The controllability of standing posture was evaluated by the mean speed of the CFP fluctuation. The muscle activity was examined with EMGs. The results were summarized as follows :
1) In a great number of subjects, the controllability of standing posture rapidly improved till the 3rd trial in each eye condition, while after the 3 rd trial changes of controllability were relatively small. Accordingly, it was suggested that by investigating the change of controllability for 5 trials, we could sufficiently detected an individual difference of the learning ability of postural control.
2) At the beginning of the practice, the controllability with open eyes was greatly superior to that with closed eyes. Although the difference of controllability between open and closed eyes decreased with advance of practice, in the 11 th trial that difference was obviously observed.
3) In a great number of subjects, the phase lag of the CFP fluctuation to the floor vibration increased till the 3rd trial according to improving controllability. In some subjects, the change of controllability was relatively small, the change of phase lag was small and also, correlations between the postural controllability and the phase lag weren't significant.
4) M. gastrocnemius was active when the CFP fluctuated forward and m. tibialis anterior when the CFP fluctuated backward greatly. In each eye condition, the magnitude of muscle activity decreased with practice and m. tibialis anterior was inactive in a great number of subjects in the last stage of the practice.
5) The controllability with open eyes didn't show a significant change after practice with closed eyes. By contrast, the controllability with closed eyes improved greatly after practice with open eyes and was approximately equal to that in the last stage of practice with closed eyes.

We examined the time course of soleus muscle fiber type composition. Soma area and succinate dehydrogenase (SDH) activity of soleus motoneurons during three weeks of hindlimb suspension (HS) in rats. Adult female Wistar rats (n=34, 252-288g BW) were divided into four groups: control (n=8), hindlimb suspended for one week (HS 1 wk, n=8), two weeks (HS 2 wk, n=9), and three weeks (HS 3 wk, n=9) . Soleus muscle fiber composition was calculated from transverse sections stained for myosin ATPase (preincubation pH 10.3, 4.3) . The fiber type composition did not change in the HS 1 wk, but in the HS 2 wk and HS 3 wk, the proportion of type I fibers decreased and that of type IIc and ha fibers increased. Using a fluorescent neuronal tracer nuclear yellow, motoneurons innervating the soleus muscle were identified, and the soma area and SDH activity were measured. The soma area did not change for up to two weeks of HS, but decreased in the HS 3 wk. Compared with control, SDH activity of soleus motoneurons decreased in the HS 1 wk. However, in the HS 2 wk, the activity increased to the level of control. In the HS 3 wk, the activity tended to increase further. Generally, muscle fibers and their motoneurons have unitary characteristics. However, these results suggest that change in soleus muscle fiber composition are not accompanied by changes in soma area and SDH activity in soleus motoneurons during three weeks of HS.

BACKGROUND: Mutations in the quinolone resistance-determining regions (QRDRs) of Acinetobacter baumannii DNA gyrase (gyrA) and topoisomerase IV (parC) are linked to fluoroquinolone (FQ) resistance. We developed a mismatched PCR-restriction fragment length polymorphism (RFLP) assay to detect mutations in the gyrA and parC QRDRs associated with FQ resistance in A. baumannii. METHODS: Based on the conserved sequences of A. baumannii gyrA and parC, two primer sets were designed for mismatched PCR-RFLP to detect mutations in gyrA (codons 83 and 87) and parC (codons 80 and 84) by introducing an artificial restriction enzyme cleavage site into the PCR products. This assay was evaluated using 58 A. baumannii strains and 37 other Acinetobacter strains that have been identified by RNA polymerase β-subunit gene sequence analysis. RESULTS: PCR amplification of gyrA and parC was successful for all A. baumannii strains. In 11 FQ -susceptible strains, the gyrA and parC PCR products were digested by the selected restriction enzymes at the site containing gyrA (codons 83 and 87) and parC (codons 80 and 84). PCR products from 47 FQ-resistant strains containing mutations in gyrA and parC were not digested by the restriction enzymes at the site containing the mutation. As for the non-baumannii Acinetobacter strains, although amplification products for gyrA were obtained for 28 strains, no parC amplification product was obtained for any strain. CONCLUSIONS This assay specifically amplified gyrA and parC from A. baumannii and detected A. baumannii gyrA and parC mutations with FQ resistance.