PubMed Health⌕ Search

Biomedical subjects

R Wammack

Publications and source records attributed to R Wammack.

24 records · Page 2Linked to original sources
PubMed1992

The appendix as a continence mechanism.

Although we have progressed very well in creating large capacity, low pressure reservoirs, the construction of a simple and reliable continent outlet still remains a problem. The appendix vermiformis serves well as a continence mechanism for either the bladder or intestinal reservoirs for urine. The different surgical techniques described in the literature are reviewed and discussed in this context. Moreover, we report on our clinical and experimental results of using the appendix during the Mainz pouch procedure for continent urinary diversion.

Adolescent↗
PubMed1992

[The "Mainz pouch" technique (bladder augmentation with ileum and cecum) for bladder augmentation, bladder substitution, and continent urinary diversion].

Back in 1983 we created a continent urinary reservoir, called the MAINZ pouch, using 10 to 15 cm. of cecum as well as two terminal ileal segments of equal length. Following detubularization, the posterior wall of the pouch is established by anastomosis of the ascending colon with the terminal ileal loop starting at the inferior aspect. The latter is then anastomosed with the next proximal ileal segment. The ureters are implanted in an antirefluxive manner in the open end technique through a submucosal tunnel of 4 to 5 cm length. For bladder augmentation the pouch is anastomosed to the bladder remnant. For bladder substitution a buttonhole incision at the most inferior aspect of the cecal pole is placed or the appendix is used for end-to-end anastomosis to the membranous urethra. For continent diversion an additional 7 to 12 cm of ileum are isolated in order to create an ileal intussuscepted valve. Alternatively the appendix can be used. Continence is achieved by submucosal embedding of the appendix into the cecal pole. A total of 346 patients underwent the MAINZ pouch procedure in Mainz and Wuppertal; 56 for bladder augmentation, 49 for bladder substitution and 241 for continent urinary diversion. We encountered early complications in 29 of the 346 patients (8.38%). Late complications were observed in 72 patients (20.8%). The major complications we encountered were stone formation inside the pouch in 19 patients and stomal stenosis in 21. 54 of the 56 patients with a bladder augmentation are completely continent (mean follow-up: 50 months, range: 10 to 83 months). All of the 49 patients who received a bladder substitution after radical cystectomy are continent during daytime. Three of these patients who do not empty their bladder at regular four hour intervals have leakage during the night (follow-up: 23 to 69 months). The revision rate due to nipple gliding and subsequent incontinence could be greatly reduced by the use of staples for fixation of the ileal nipple and the use of the appendix. For correction of the most frequently occurring complications standardized techniques have been developed.

Cecum↗
PubMed1992

Seven years experience with the Mainz pouch procedure.

In 1983 we created a form of continent urinary diversion termed the Mainz pouch procedure utilizing cecum and ileum. For creation of the reservoir 10 to 15 cm of cecum and ascending colon as well as two terminal ileal segments of equal length are isolated and detubularized. The posterior wall of the pouch is completed by anastomosis of the ascending colon with the terminal ileal loop starting at the inferior aspect. The latter is then anastomosed with the next proximal ileal segment. The ureters are implanted in an antirefluxive manner in the open end technique through a submucosal tunnel of 4 to 5 cm of length. For bladder augmentation the pouch is anastomosed to the bladder remnant. For bladder substitution a buttonhole incision at the most inferior aspect of the cecal pole or the appendix is used for end-end anastomosis to the membrancus urethra. For continent diversion and additional 8 to 12 of ileum are isolated in order to create an ileal intussuscepted valve. Alternatively the appendix can be used. Continence is achieved by submucosal embedding of the appendix into the cecal pole. A total of 281 patients underwent the Mainz pouch procedure, 54 for bladder augmentation, 7 for bladder replacement and 200 for continent urinary diversion. We encountered early complications in 15 of the 281 patients (5.3%). Late complications were observed in 63 patients (22.4%). The major complications we encountered were stone formation inside the pouch in 17 patients and stomal stenosis in 19. Fifty-two of the 54 patients with a bladder augmentation are completely continent (mean follow-up: 50 months, range: 10 to 83 months). All of the 27 patients who received a bladder substitution after radical cystectomy are continent during daytime. Three of these patients who do not empty their bladder at regular four hour intervals have leakage during the night (follow-up: 23 to 69 months). The revision rate due to nipple gliding and subsequent incontinence could be greatly reduced by the use of staples for fixation of the ileal nipple and the use of the appendix. For correction of the most frequently occurring complications standardized techniques have been developed.

Cecum↗
PubMed1988

Endogenous opioid inhibition of the release of oxytocin from the isolated rat neurohypophysis during high-frequency stimulation of the pituitary stalk.

Isolated rat neurohypophyses were superfused in vitro and the release of vasopressin and oxytocin determined by radioimmunoassays. Hormone release was evoked by short trains of electrical stimulation (10 s), at frequencies from 15 to 100 Hz. The release of oxytocin evoked by stimulation up to 80 Hz was increased 2- to 3-fold in the presence of naloxone. The evoked release of vasopressin was not significantly affected by naloxone. In conclusion, opioid inhibition of oxytocin release operates also under stimulation conditions which mimic the electrical activity (i.e. short bursts of high frequencies) of physiologically activated (e.g. by suckling) oxytocinergic neurons.

Animals↗
PubMed1988

Differential effects of potassium channel blockers on neurohypophysial release of oxytocin and vasopressin. Evidence for frequency-dependent interaction with the endogenous opioid inhibition of oxytocin release.

Isolated rat neurohypophyses were fixed by their stalks to a platinum wire electrode and superfused with Krebs-HEPES solution. Vasopressin and oxytocin released into the medium were determined by specific radioimmunoassays. Hormone secretion was increased by electrical stimulation of the pituitary stalk at different frequencies. The effects of several potassium channel blockers, tetraethyl-ammonium (TEA) ions, 4-aminopyridine (4-AP) and 3,4-diaminopyridine (3,4-DAP) were tested. The release of vasopressin and oxytocin evoked by electrical stimulation with 900 pulses at 15 Hz (about 900 and 1,000 microU, respectively) was about 10 times higher than that evoked by 900 pulses at 3 Hz. Both 10 and 30 mmol/l TEA enhanced the release of vasopressin evoked by stimulation at 3 and 15 Hz, by 25- and 2-fold, respectively, to attain a maximum release of about 1,800 microU per stimulation. The stimulated release of oxytocin attained a maximum of about 9,000 microU at 15 Hz in the presence of 10 mmol/l TEA or at 3 Hz with 30 mmol/l TEA. Thus, in the presence of maximally effective concentrations of TEA both stimulation frequencies (3 and 15 Hz) were equieffective in evoking release of vasopressin and oxytocin. 4-AP or 3,4-DAP enhanced the release of vasopressin evoked by 15 Hz stimulation maximally to about 1,600 microU. In the presence of 4-AP or 3,4-DAP the release of oxytocin evoked by stimulation at 15 Hz increased maximally to about 8,000 microU and that evoked by stimulation at 3 Hz to about 1,500 microU.(ABSTRACT TRUNCATED AT 250 WORDS)

4-Aminopyridine↗