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Biomedical subjects

M Hohenfellner

Publications and source records attributed to M Hohenfellner.

66 records · Page 4Linked to original sources
PubMed1995

[Permanent electrostimulation of sacral spinal nerves with an implantable neurostimulator in treatment of fecal incontinence].

Functional deficits of the striated muscular anal sphincter frequently result in faecal incontinence. The therapeutic options for patients without a defined muscular defect are limited. Our patient without defined lesion, but with a clinically relevant reduction of the voluntary force of the anal sphincter resulting in daily loss of stool, underwent an electrostimulation procedure of the sacral spinal nerves. The procedure was divided in three steps: acute percutaneous testing, temporary percutaneous nerve evaluation and permanent electrostimulation phase with an implantable neurostimulation device. In all three phases electrostimulation of the third sacral spinal nerve resulted in a positive clinical effect and an increase of the anal canal closure pressure. By application of permanent electrostimulation of the third sacral spinal nerve the patient became completely continent.

Adult↗
PubMed1993

Reservoir characteristics of Mainz pouch studied in animal model. Osmolality of filling solution and effect of oxybutynin.

In a canine model of the Mainz pouch, intracavitary pressure and compliance were measured during instillation of isosmotic and hyperosmotic (900 mmol/kg water) solutions of saline. Wall properties of small- and large-bowel segments of the pouch were assessed individually by sonomicrometry. Intraluminal pressures increased more steeply during filling with hyperosmotic solution, resulting in reduced distensibility of small- and large-bowel segments. Additionally, instillation of the hyperosmotic solution resulted in increased amplitudes and frequency of intracavitary pressure waves. The results indicate that this was the result of a combination of intensified bowel contractions and an increased mural tension. Topical application of oxybutynin abolished these effects. These findings are reviewed in light of the nocturnal increase in urine osmolality, its correlation with nocturnal incontinence in patients with enterocystoplasty, and possible treatment choices.

Animals↗
PubMed1993

Nitric oxide and cGMP: mediators of pelvic nerve-stimulated erection in dogs.

We sought to determine whether the L-arginine-nitric oxide-guanosine 3',5'-cyclic monophosphate (cGMP) pathway, known to mediate neurostimulation-induced smooth muscle relaxation in penile tissue of rabbits and humans in vitro, is operative also in vivo. Adult male dogs (n = 9) were subjected to direct electrical stimulation of the pelvic nerves to induce penile tumescence. Intracavernous injection of the nitric oxide-releasing substance S-nitroso-N-acetylpenicillamine resulted in similar tumescence. Intracavernous injection of a specific inhibitor of nitric oxide synthesis, NG-nitro-L-arginine, blocked pelvic nerve-stimulated tumescence, and this was partially reversed by intracavernous injection of the nitric oxide precursor L-arginine. Furthermore, neurostimulated tumescence was inhibited by methylene blue, an inhibitor of cytosolic guanylate cyclase and enhanced by M&B 22948, a cGMP phosphodiesterase inhibitor. These in vivo findings support the hypothesis that cavernous smooth muscle relaxation and penile tumescence are mediated by nitric oxide and cGMP.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1992

Interstitial cystitis: increased sympathetic innervation and related neuropeptide synthesis.

To investigate the possibility of a neural deterioration of the bladder wall in interstitial cystitis, bladder tissue from 10 patients with interstitial cystitis was compared with that from 10 control subjects by means of immunohistochemistry. An enhanced innervation of the bladder in the submucosa and detrusor muscle was found to represent an increase of sympathetic but not cholinergic neurons. In interstitial cystitis the number of neurons positive for vasoactive intestinal polypeptide and neuropeptide Y was higher and carried a larger number of axonal varicosities, whereas the number of neurons positive for substance P and calcitonin-gene-related peptide was not significantly different in both groups. We conclude that interstitial cystitis is associated with increased sympathetic outflow into the bladder and altered metabolism of vasoactive intestinal polypeptide and neuropeptide Y. Since similar changes have been observed in other inflammatory diseases of a presumably autoimmune nature, such as rheumatoid arthritis, Crohn's disease and colitis ulcerosa, the pathophysiology of interstitial cystitis may share common pathways with the latter. Experience in these diseases may facilitate a better understanding of the pathophysiology of interstitial cystitis and suggest new therapeutic concepts.

Adrenergic Fibers↗
PubMed1992

Tumor in the horseshoe kidney: clinical implications and review of embryogenesis.

We report on 3 patients with tumor in a horseshoe kidney, 1 of whom had bilateral tumor (renal cell cancer on the right side and urothelial cancer on the left side). Tumors that arise predominantly in the bridge of a horseshoe kidney can mimic the symptoms of an intra-abdominal disease process. Besides routine diagnostic procedures, angiography is essential to plan the surgical approach, which in principle should be organ-sparing. The literature of the embryology of the horseshoe kidney was reviewed for a relationship between the abnormal renal development and the site of tumorigenesis, and for development of a key for the wide variation of blood supply. Recently reported data suggest that the theory of a mechanical fusion is valid only for horseshoe kidneys with a fibrous isthmus but that an abnormal migration of the posterior nephrogenic area causes the majority of horseshoe kidneys in which the isthmus consists of parenchyma. Development of the isthmus through abnormal migration could predispose this location for renal cell cancer and would explain the varying forms of blood supply. Additionally, this hypothesis supports the previously raised assumption that horseshoe kidneys may be the result of teratogenic factors, which also may be responsible for the known increased incidence of related congenital anomalies and of nephroblastoma.

Adult↗
PubMed1992

Site of deafferentation and electrode placement for bladder stimulation: clinical implications.

Based on the clinical experience of treating neurogenic bladders by the electrical stimulation of the ventral sacral roots, neuroanatomical and neurophysiologic studies were designed to study the mechanism of detrusor-sphincter dyssynergia during electrical stimulation of the sacral roots. An experimental model was developed to decrease the stimulation response of the pelvic floor and external urethral sphincter muscles while preserving bladder contraction. The significance of the site of deafferentation and electrode implantation was evaluated under functional and clinical aspects. Our results indicate that a combination of intradural deafferentation and extradural electrode implantation may offer maximal deafferentation efficiency with minimal surgical risk. Intradural deafferentation is facilitated by a consistent arrangement of sacral roots with the dorsal roots running laterally to the ventral roots at the site of their exit from the dura. Detrusor-sphincter dyssynergia can be reduced by selective division of ventral sacral rootlets innervating the striated musculature of the pelvic floor and the urethral sphincter.

Afferent Pathways↗
PubMed1992

Cellular changes in acute renal failure: functional and therapeutic consequences.

Prerenal, renal and postrenal forms of acute renal failure (ARF) are distinguishable. Prerenal forms are reversible by effective treatment of the underlying extrarenal disorder(s). Damage of the endothelium and the tubular epithelium indicates progress of prerenal to renal ARF or induction of primary renal ARF. A continuous survey of renal function based on the cellular and functional pathophysiologic pathways of ARF allows adequate and specific therapy. As both extra- and intrarenal causes of ARF may occur simultaneously under clinical conditions, a broad therapeutic approach should be used: treatment of the extrarenal disorder augmented by measures to reduce the cellular workload, cell-protective therapy, support of microcirculation rheology, and inhibition of prerenal vasoconstriction.

Acute Kidney Injury↗
PubMed1992

[Value of functional examination techniques for the assessment of the clinical aspects of benign prostatic hyperplasia].

The urodynamic relevance of benign prostatic hyperplasia (BPH) is determined by evaluation of the symptoms of prostatism, the degree of infravesical obstruction and the size of adenoma. The combination of all three findings, but also the presence of at least of two of these findings suggest a diagnosis of clinical BPH. Standard diagnostic procedures consist in elicitation of the history, evaluation of symptoms, physical examination, urinalysis and laboratory examination of serum creatinine; with evaluation of residual urine and uroflowmetry in addition, surgical therapy can be expected to be successful in 93%. Urinary flow rates exceeding 15 ml/s and/or discrepancies between symptoms and findings need further assessment by synchronous pressure-flow studies for differential diagnosis between unobstructed flow and high-flow outflow obstruction. Complete videourodynamic investigation is indicated both in patients with combined BPH and urinary incontinence without residual urine and in patients with BPH and suspected or known neurological disorder. Surgical treatment of BPH involves the risk of postoperative incontinence in patients with detrusor hyperreflexia combined with a functional or morphological lesion of the external urinary sphincter.

Diagnosis, Differential↗
PubMed1991

The nutcracker syndrome: new aspects of pathophysiology, diagnosis and treatment.

Magnetic resonance imaging (MRI) was used to study vascular anatomy in 3 patients with the nutcracker syndrome and in 10 healthy volunteers. From these studies an abnormal branching of the superior mesenteric artery from the aorta was identified as being the cause of the nutcracker syndrome. Consequently, surgical transposition of the left renal vein to achieve an unobstructed renal venous backflow was performed successfully in 2 patients, while 1 underwent nephrectomy. In 1 patient adjuvant ureteral instrumentation became necessary to aid occlusion of persisting shunts between peripelvic venous varicosities and the urinary tract. Awareness of the pathophysiology of the nutcracker syndrome ensures an early diagnosis, which should be confirmed by a combination of diagnostic procedures, including MRI.

Adult↗
PubMedDate not supplied

Blood sample analysis and monitoring of hemodynamic parameters and renal function in the conscious rat.

A method is described for chronic instrumentation of the rat with arterial and venous catheters. The technique minimizes the risk of catheter occlusion and damage, and reduces restraint of the animals during the evaluation. In the conscious animal, hemodynamic parameters and renal function can be monitored while substances are injected or blood samples withdrawn.

Animals↗