The involvement of type IV pili and the phytochrome CphA in gliding motility, lateral motility and photophobotaxis of the cyanobacterium Phormidium lacuna.

Phormidium lacuna is a naturally competent, filamentous cyanobacterium that belongs to the order Oscillatoriales. The filaments are motile on agar and other surfaces and display rapid lateral movements in liquid culture. Furthermore, they exhibit a photophobotactic response, a phototactic response towards light that is projected vertically onto the area covered by the culture. However, the molecular mechanisms underlying these phenomena are unclear. We performed the first molecular studies on the motility of an Oscillatoriales member. We generated mutants in which a kanamycin resistance cassette (KanR) was integrated in the phytochrome gene cphA and in various genes of the type IV pilin apparatus. pilM, pilN, pilQ and pilT mutants were defective in gliding motility, lateral movements and photophobotaxis, indicating that type IV pili are involved in all three kinds of motility. pilB mutants were only partially blocked in terms of their responses. pilB is the proposed ATPase for expelling of the filament in type IV pili. The genome reveals proteins sharing weak pilB homology in the ATPase region, these might explain the incomplete phenotype. The cphA mutant revealed a significantly reduced photophobotactic response towards red light. Therefore, our results imply that CphA acts as one of several photophobotaxis photoreceptors or that it could modulate the photophobotaxis response.

Prospective, blinded, randomized crossover study of gait rehabilitation in stroke patients using the Lokomat gait orthosis.

OBJECTIVE: Treadmill training with partial body weight support has been suggested as a useful strategy for gait rehabilitation after stroke. This prospective, blinded, randomized controlled study of gait retraining tested the feasibility and potential efficacy of using an electromechanical-driven gait orthosis (Lokomat) for treadmill training. METHODS: Sixteen stroke patients, mostly within 3 months after onset, were randomized into 2 treatment groups, ABA or BAB (A = 3 weeks of Lokomat training, B = 3 weeks of conventional physical therapy) for 9 weeks of treatment. The outcome measures were the EU-Walking Scale, Rivermead Motor Assessment Scale, 10-m timed walking speed, 6-minute timed walking distance, Motricity Index, Medical Research Council Scale of strength, and Ashworth Scale of tone. RESULTS: The EU-Walking Scale, Rivermead Motor Assessment Scale, 6-minute timed walking distance, Medical Research Council Scale, and Ashworth Scale demonstrated significantly more improvement during the Lokomat training phase than during the conventional physical therapy phase within each 3-week interval. CONCLUSIONS: Despite the small number of patients, the present data suggest that the Lokomat robotic assistive device provides innovative possibilities for gait training in stroke rehabilitation while eliminating prolonged repetitive movements in a nonergonomic position on the part of the physical therapist.

Preserved cutaneous silent periods in severe entrapment neuropathies.

Noxious digital nerve stimulation during isometric contraction of hand muscles leads to transient suppression of the electromyographic activity, the so-called cutaneous silent period (CSP), which is mostly due to a spinal reflex mediated by A-delta fibers. We investigated two patients with carpal tunnel syndrome (CTS) and two patients with ulnar entrapment at the elbow (UNE), in whom routine sensory conduction studies failed to document afferent fiber continuity across the lesion site. In three patients, motor nerve conduction studies and electromyography failed to demonstrate intact efferent fibers. Noxious stimulation of digit II elicited distinct CSPs in ulnar-innervated hand muscles in both patients with CTS, and stimulation of digit V evoked CSPs in median-innervated hand muscles in both UNE patients. The presence of a CSP can only be explained by preserved A-delta fibers crossing the respective lesion site. Thus, preserved CSPs may serve to document residual nerve continuity in severe entrapment neuropathies when fast-conducting fibers are so compromised that their continuity cannot be detected by standard electrodiagnostic techniques.