Artificial organs
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Spinal cord injured patients with a suprasacral lesion usually develop a spastic bladder. The hyperreflexia of the detrusor and the external sphincter causes incontinence and threatens those patients with recurrent urinary tract infections (UTI), renal failure, and autonomic dysreflexia. All of these severe disturbances may be well managed by sacral deafferentation (SDAF) and implantation of an anterior root stimulator. ⋯ SDAF is able to restore the reservoir function of the urinary bladder and to achieve continence. Autonomic dysreflexia disappeared in most of the cases. By means of an accurate adjustment of stimulation parameters it is possible to accomplish low resistance micturition. The microsurgical technique requires an intensive education. One has to be able to manage late implant complications.
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The aims of the present study were to investigate whether temporal summation of the nociceptive withdrawal reflex depends on the stimulation site on the sole of the human foot, and to characterize the reflex receptive fields (RRF) of lower limb muscles to repetitive stimulation. The cutaneous RRFs were assessed in 15 subjects in sitting position by recording the EMG from five lower leg muscles and the kinematic responses (ankle, knee, and hip joints) to repetitive painful electrical stimulation. The stimulus consisted of a series of five stimuli (frequency: 3 Hz) delivered randomly at 10 different sites on the sole of the foot. ⋯ The enlargement of the RRF reflects spinal temporal summation leading to gradually stronger reflex responses. The degree of temporal summation was dependent on stimulation site. The facilitation of the withdrawal reflex responses due to repetitive stimulation might have potential applications in the rehabilitation engineering field, where these reflexes could be used to assist gait of patients with central nervous system injuries.
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To investigate the alterations of mechanical properties in pre- (A) and post- (B) stenotic aortic regions after an experimentally induced stenosis in the descending thoracic aorta. ⋯ A nonhemodynamically significant experimental stenosis located at the level of the descending thoracic aorta induced reverse blood flow before and after the stenosis. The higher the reverse flow, the more collagen fibers were produced and the stiffer the aortic wall. Since hypercholesterolemia can be ruled out as a hardening factor in the present study, disturbed flow seems to be an independent factor which activates fibroblasts to overproduce collagen and to eventually reduce the aorta's compliance.