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Biomedical subjects

U Jonas

Publications and source records attributed to U Jonas.

At least 289 records · Page 16Linked to original sources
PubMed1975

[Cytostatic therapy of tumors under conditions of partial synchronisation with particular reference to malignant tumors of the testicle (author's transl)].

Cytostatic therapy under conditions of "partial synchronisation" is reported. 12 patients with extensive metastases of malignant testicular tumors and 5 other patients with other rapidly growing metastasizing tumors were treated. They had all previously undergone extensive operation, irradiation and some also treatment with cytostatics. Vincristine/ifosfamide and bleomycin/ifosfamide were given as stosstherapy and trofosfamid (Ixoten) as maintenance therapy. There was complete remission of the lung metastases in 8 of the metastasizing testicular tumors. Retroperitoneal and supraclavicular metastases became operable. In 2 patients there was a partial remission lasting 4-6 months. Complete remission could be obtained in the other patients.

Adult↗
PubMed1975

Recovery of bladder function after spinal cord transection.

All dogs having undergone spinal cord transection in our study exhibited a postoperative phase of spinal shock, with complete urinary retention and areflexic detrusor. This shock phase lasted between 2 and 6 weeks. Sequential pressure studies of paraplegic dogs substantiated the clinical supposition that urinary retention during spinal shock phase is caused by an unresponsive detrusor. The sphincteric mechanism could be the implicated as an etiologic agent. Return of detrusor reflex activity was observed in all animals.

Animals↗
PubMed1975

Studies on vesicourethral reflexes. I. Urethral sphincteric responses to detrusor stretch.

For the purpose of studies on vesicourethral reflexes, a model was established wherein the vesicosphincteric unit is divided into two separate compartments. In one group, the compartments were formed by single mucosal separation but muscular continuity was maintained. In the other, complete interruption of muscular continuity was performed by full bladder wall thickness separation. To maintain the proper nerve and blood supply to the upper compartment, the separation was made below the ureteral orifices and urinary diversion was accomplished through ureterosigmoidostomy. Postoperative cystographic studies demonstrated the complete separation. Detailed pre- and postoperative physiologic studies were done. Spontaneous contraction of the upper compartment excited contraction of the detrusor component of the lower compartment where muscular continuity was maintained. Contraction of the upper compartment induced reflex relaxation of the sphincteric element, regardless of whether the muscular continuity was maintained or interrupted. Flaxedil and Regitine both led to a drop in resting urethral pressure and abolished the drop in urethral pressure in response to contraction of the upper detrusor compartment. Although muscular contraction might be a contributory factor, it is clear that a nerve-mediated spinal reflex exists that induces drop in urethral resistance in response to detrusor contraction.

Animals↗
PubMed1975

Studies on the feasibility of urinary bladder evacuation by direct spinal cord stimulation. I. Parameters of most effective stimulation.

In 30 female dogs, spinal cord stimulation was tested to find the optimal parameters producing good voiding and, hopefully, total bladder emptying. Twelve different electrodes or application modifications were examined. Variable frequencies, stimulus duration, and voltages were applied. Search of the site of highest detrusor response (micturition center) was easily identifiable. It became obvious that electrode design was not of critical importance: the responses were basically the same whether we used the wrap-around electrode, which stimulates an entire level, or the coaxial electrode which theoretically limits the current spread around its minute exposed tip. The stimulation parameters that gave the best results were: 2 to 5 volts; frequency: 10 to 15 cps; duration 1 msec. The site of highest detrusor response was round vertebral level L5 1/2, corresponding to cord level S2-4. Generally, no voiding was obtained because of too high sphincteric contraction during stimulation; it appeared that a sphincteric center overlaps the micturition center in either direction. To achieve successful voiding during stimulation, a separation of these two centers with selective stimulation of the detrusor center is necessary, eleiminating sphincteric contraction.

Animals↗
PubMed1975

Studies on the feasibility of urinary bladder evacuation by direct spinal cord stimulation. II. Poststimulus voiding: a way to overcome outflow resistance.

Electrical stimulation of the spinal cord micturition center is effective in inducing strong detrusor contraction. Simultaneous sphincteric contraction, however, prevents voiding from occurring. At the end of stimulation a sharp drop in sphincteric activity takes place, with a concomitant and slower drop in intravesical pressure--resulting in a short poststimulus phase where bladder pressure exceeds urethral resistance and a spurt of urine is passed. This brief period was put to use by applying a train of short stimuli of 1-sec duration and separated by 1-sec intervals, following which complete bladder emptying could be obtained in an average time of 30 sec. This poststimulus voiding was constantly observed after high spinal cord transection. It can be accomplished without the need for neurectomy, sphincterectomy, or drug-induced muscular blockade.

Animals↗
PubMed1975

Spinal cord stimulation versus detrusor stimulation. A comparative study in six "acute" dogs.

Spinal cord stimulation and direct bladder stimulation were evaluated in an "acute" comparative study of six dogs. Both means were effective in inducing strong detrusor contraction and rise in intravesical pressure. Spinal cord stimulation, however, induced greater rise in outflow resistance than did direct bladder stimulation. Effective net intravesical pressure was higher with direct stimulation and thus more successful in achieving bladder emptying.

Anal Canal↗