Biomedical subjects

J R Scheepe

Publications and source records attributed to J R Scheepe.

6 recordsLinked to original sources

PubMed1999

Smooth muscle fatigue due to repeated urinary bladder neurostimulation: an in vivo study.

The presented study investigates the influence of different pause lengths between two consecutive stimulations of the S3 roots on intravesical pressure during bladder neurostimulation. In eight male foxhounds (aged 7-18 months), laminectomy and placement of a modified Brindley electrode were performed. In four series with different pause lengths between two consecutive stimulations (1, 3, 5, and 15 min), the maximum intravesical pressure was measured during stimulation. The changes in intravesical pressure were registered in these four series, each series with six stimulations. A 15-min interval elapsed before the commencement of each series. In the series with a pause length of 15 min, the consecutive stimulations did not result in significant changes in maximum intravesical pressure. In the 5-min series, a significant decrease in intravesical pressure was not observed after the third stimulation. In the 3-min series, a significant decrease was seen at almost every stimulation (average decrease of 3.8% per stimulation) and in the 1-min series, a significant decrease was also observed at almost every stimulation (average decrease of 5.9% per stimulation). The results of repeated bladder neurostimulation demonstrate that the maximum intravesical pressure is dependent on the pause length between two consecutive stimulations. The detrusor muscle showed reversible and short-lived signs of fatigue. This implies the importance of a minimum 5-min interval between two subsequent stimulations. A pause length <5 min leads to a falsification of the results and thus to lower validity of the investigation.

Animals↗

PubMed1999

Extradural cold block for selective neurostimulation of the bladder: development of a new technique.

PURPOSE: Cryotechnique for selective block of the urethral sphincter and simultaneous activation of the bladder was developed to achieve physiological micturition during sacral anterior root stimulation (SARS). MATERIALS AND METHODS: In ten foxhounds SARS of S2 was carried out while extradurally both spinal nerves S2 were cooled down from positive 25C in a stepwise fashion until a sphincter block was observed. Subsequently, SARS of S2 was performed while the pudendal nerves were cooled down from + 15C. The effects of spinal and pudendal nerve cold block on the urethral sphincter and bladder during SARS and the recovery time were monitored by urodynamic investigation. RESULTS: A complete cold block of the urethral sphincter during spinal nerve cooling was achieved in all cases. During pudendal nerve cooling, the sphincter was completely blocked in two, and incompletely blocked in four dogs. Cold block temperature of the spinal nerves averaged +11.7C and of the pudendal nerves +6.2C. During SARS and spinal nerve cooling, an increase in intravesical pressure up to 13 cm. water was recognized, and recovery time was on average 6.6 minutes. Intravesical pressure remained unchanged during pudendal nerve cooling, with recovery time being less than 1 minute. The cold block was always reversible. CONCLUSIONS: Cryotechnique is an excellent method for selective and reversible block of the urethral sphincter during SARS to avoid detrusor-sphincter-dyssynergia. The application of cryotechnique in functional electrical stimulation leads to an improvement of quality of life in para- or tetraplegic patients because of selective nerve stimulation with optimization of micturition, standing, walking and grasping and does so without the necessity of surgical dorsal root rhizotomy.

Animals↗

PubMed1998

Smooth muscle electromyography of the urinary bladder.

To elucidate smooth muscle activity of the urinary bladder, we utilized an optimized animal model and a specially developed, computer-aided data acquisition and analysis system for bioelectrical signals. Twenty-five Wistar rats were pharmacologically paralyzed and artificially respirated. The urinary bladder was exposed by a suprapubic midabdominal incision, and both ureters were ligated to prevent physiological filling of the bladder. The bladder was initially emptied by slight manual pressure and was then filled via a transurethral catheter in 0.1-ml steps to a maximum of 0.45 ml with physiological saline. A custom-made, gold-plated needle electrode was tangentially guided by a micromanipulator to the smooth muscle of the bladder dome, and the recordings commenced. Furthermore, smooth muscle EMG recordings of the bladder were performed after pharmaco-stimulation of the detrusor with carbachol. Initial results demonstrate that, with the animal model presented here, it is possible to record reproducible and almost artifact-free smooth muscle activity from the urinary bladder. All experiments displayed a stochastic distribution of similar electrical events, increasing in appearance and amplitude with increased bladder volume and after pharmacostimulation with carbachol. Two-dimensional power spectrum analysis revealed a main signal frequency below 1 Hz.

Animals↗

PubMed1998

Highlights on the latest developments in neurourology - diagnostic technology.

Improved appreciation of detrusor malfunction within the complex pathology of lower urinary tract syndrome has led to increased interest in detrusor muscle disorders and possible detrusor myopathies. The rapid development of alternative methods and new pharmacological agents for the treatment of lower urinary tract dysfunction initiate subtle differential diagnosis of the underlying pathology. Research activities related to bladder physiology, neurophysiology and neuropharmacology have increased in the last 10 years. Primarily a purely basic scientific field, neurourology now commences to become a clinically highly significant and useful research domain. This article offers insight into the latest developments in the diagnostic techniques of this exciting field. One of these is smooth muscle EMG of the urinary bladder that aims at distinguishing between signal pattern changes and subsequent evaluation of the different functional and electrophysiological states of smooth muscle cells in various pathologies or in pharmacological tests during urodynamic investigation. A second innovative method in geriatric patients is the measurement of the sensory input to the brain due to bladder distention. The reported techniques are two new examples of lower urinary tract evaluation that contribute to knowledge on the physiology and pathophysiology of the urinary bladder.

Clinical Laboratory Techniques↗

PubMed1998

Long-term followup and selection criteria for penile revascularization in erectile failure.

PURPOSE: We report the long-term results of penile revascularization surgery for erectile failure and suggest possible selection criteria for this controversial surgical procedure. MATERIALS AND METHODS: In 7 years 62 impotent men who did not respond to pharmacotherapy underwent microsurgical penile revascularization and completed long-term followup evaluation in 41 months (range 18 to greater than 62) consisting of a detailed questionnaire, duplex sonography and optional pharmacotherapy or angiography. The Virag procedure was chosen for the first 7 patients, the original Hauri technique for the next 13 and the modified Mannheim triple anastomosis for 42. RESULTS: Of all patients 34% achieved spontaneous and another 20% pharmacologically induced erections. Success in diabetics and older patients was lower (43% for diabetics, 39% for those older than 50 years at surgery), while it was high in men with less than 2 risk factors (58%) as well as in younger patients (69% for those up to 50 years old). Shunt patency was 92%. Complications such as glans hyperemia developed in 13% of patients, shunt thrombosis in 8% and inguinal hernias in 6.5%. CONCLUSIONS: Patient selection is vital for the successful outcome of penile revascularization surgery. We adhere to strict selection criteria, such as patient age maximum of 50 years, less than 2 risk factors, no recent diabetes and termination of nicotine abuse. Penile revascularization surgery is highly indicated in this group of patients, especially since it is the only causal therapy for erectile failure.

Adult↗

PubMed1996

Recording the corpus cavernosum electromyogram: principles and problems.

PURPOSE: To apply digital signal acquisition and analyzing techniques to the collection and interpretation of electromyographic data of the cavernous body. MATERIALS AND METHODS: Electromyographic recordings were performed in the cavernous bodies of anesthetized, spontaneously breathing dogs under resting conditions and after intracavernous pharmacostimulation with norepinephrine, angiotensin II, phentolamine/papaverine, diethylether and T61. RESULTS: Resting corpus cavernosum activity was ill-coordinated and provided little information. Signal energy was confined largely to the range below 20 Hz. Pharmacostimulation with norepinephrine or angiotensin increased frequency and amplitude of the potential transients and decreased the random components. Administration of a combination of phentolamine and papaverine made the signals very regular and increased periodicity. Blockade of electrical membrane events with diethylether removed all signal components except for electrical and biological noise. CONCLUSIONS: Our findings indicate that electromyograms from the corpus cavernosum can be recorded even under adverse conditions. Signal properties, however, are such that the application of computer-aided data processing and analysis to the evaluation of these myograms is imperative.

Amides↗