0000000000033743
AUTHOR
R. Wammack
Opioid Inhibition of Oxytocin Release, but not Autoinhibition of Dopamine Release May Involve Activation of Potassium (K+) Channels
ABSTRACT Release of oxytocin (Ox) or dopamine (DA) from the isolated neural lobes or neurointermediate lobes, respectively, was evoked by high K + (30 or 45 mM). Naloxone (1-10 μmol/l) which largely enhances the impulse-induced release of Ox had no effect on Ox release evoked by 30 or 45 mM K + . In the presence of 10 mM tetraethylammonium (TEA), Ox release evoked by 30 or 45 mM K + was increased 2-3fold; nevertheless, naloxone caused a further 2-3fold increase. Barium (500 μM) and quinidine (300 μM) antagonized the effect of naloxone observed in the presence of TEA. (-)-Sulpiride (10 μM) enhanced the release of DA evoked by 30 and 45 mM K + by 94 % and 19 %, respectively. TEA enhanced the …
Long-term results of ileocecal continent urinary diversion in patients treated with or without previous pelvic irradiation
Purpose: Patients who receive pelvic irradiation may require urinary diversion to manage complications resulting from progressive malignancy or radiotherapy. The choice of urinary diversion is an important issue and remains controversial. We characterized the long-term outcome of urinary diversion with a continent ileocecal reservoir in patients who received pelvic irradiation versus those who underwent urinary diversion without previous irradiation. Materials and Methods: Continent urinary diversion with an ileocecal reservoir (Mainz pouch 1) was performed in 36 irradiated patients in a 9-year period. Morbidity, mortality, the reoperative rate and parameters associated with the surgical pr…
Conversion and Undiversion Surgery
The Mainz pouch II (sigma rectum pouch).
A low pressure rectosigmoid reservoir for urine is created obviating the need for colostomy, augmentation or extensive bowel surgery. Antimesenteric splitting of the intestine at the rectosigmoid junction and subsequent side-to-side anastomosis are performed. Urodynamic data demonstrate that the detubularization is effective in rendering high pressure bowel contractions ineffective. Without the risk of damaging the mesentery the pouch is fixed at the promontory, which lessens the risk of ureteral kinking and upper urinary tract dilatation. The technique is indicated not only in cases of failed ureterosigmoidostomy but also for primary urinary diversion. All 47 patients who underwent the ope…
The sigma rectum pouch (Mainz pouch II)
A low-pressure reservoir for urine is created by antimesenteric splitting and side-to-side anastomosis of the rectosigmoid, the expectation being to obtain better continence rates and better protection of the upper tract than are achievable by ureterosigmoidostomy. Between 1990 and August 1993 the procedure was performed in 73 patients (59 adults and 14 children) whose mean age was 43.5 years. The indications were malignancy (n = 55), bladder exstrophy/epispadias (n = 14), trauma (n = 3), and sinus urogenitalis (n = 1). Of the 73 patients, 69 were followed for a mean period of 127 (range, 1-34) months. In all, 5 early complications were encountered (6.8%). In addition, 8 late complications …
Long-Term Results of Ileocecal Continent Urinary Diversion in Patients Treated With and Without Previous Pelvic Irradiation
Patients who receive pelvic irradiation may require urinary diversion to manage complications resulting from progressive malignancy or radiotherapy. The choice of urinary diversion is an important issue and remains controversial. We characterized the long-term outcome of urinary diversion with a continent ileocecal reservoir in patients who received pelvic irradiation versus those who underwent urinary diversion without previous irradiation.Continent urinary diversion with an ileocecal reservoir (Mainz pouch 1) was performed in 36 irradiated patients in a 9-year period. Morbidity, mortality, the reoperative rate and parameters associated with the surgical procedure were determined at a medi…
Pediatric Urinary Diversion: Review and Own Experience
New insights into the diseases of childhood, profound improvements and new developments in surgical techniques as well as the knowledge gained from long-term follow-up have altered the strategies and indications for urinary diversion in childhood. Continent urinary diversion is generally the method of choice. We are able to construct high capacity, low pressure reservoirs to protect the upper urinary tract and achieve continence. Nowadays, there is hardly any indication for permanent cutaneous urinary diversion. Temporary and intermediate cutaneous diversion are used only when serious conditions such as renal function deterioration occur. The possibility to convert any incontinent form of u…
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, tetraethylammonium (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 μU, respectively) was about 10 times higher than that evoked by 900 pulses at 3 Hz. Both 10 and 3…
Mechanical and electrophysiological effects of cromakalim on the human urinary bladder.
The effects of cromakalim on spontaneous and induced mechanical activity of human detrusor muscle were investigated in vitro. Cromakalim produces a concentration-related decrease of spontaneous as well as carbachol- and K(+)-evoked contractions. This is the first study to utilize the patch clamp technique to elucidate the mechanism of action of cromakalim on human detrusor cells. Cromakalim hyperpolarizes the detrusor cells by increasing the net outward current which is most likely carried by potassium ions. In the human urinary bladder, this effect is mediated by a glibenclamide-sensitive potassium channel, as glibenclamide is able to diminish the relaxant effect of cromakalim and to preve…
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.
Ileocecal valve reconstruction during continent urinary diversion.
During construction of an ileocecal reservoir, such as the Mainz or Indiana pouch, the ileocecal valve is lost. Subsequently, the intestinal transit time is shortened and malabsorption as well as diarrhea may result. Patients having undergone previous bowel resection as well as children with myelomeningocele who often already have frequent defecations will be heavily affected by the loss of the ileocecal valve. We have functionally reconstructed the ileocecal valve by embedding ileum into the ascending colon via a submucosal tunnel in analogy to the technique used when creating the continence mechanism during the Mainz pouch procedure using the appendix. Experimental results in 15 dogs demo…
Ureteropelvic junction obstruction in childhood.
Wilms' tumor ? treatment and prognosis of 373 children
Between June 1980 and June 1988, 373 patients with Wilms' tumors were diagnosed and treated (34.5%, stage I; 34.5%, stage II; 14.8%, stage III; 10.7%, stage IV; and 5.4%, stage V). In all, 11% of the patients were diagnosed as a result of routine checkup examinations. The tumor volume was 400 ml in 52.7%. Overall, 78.7% of the patients had a standard-type Wilms' tumor, 7% had a low-grade malignancy lesion and 14.3% had a high-grade-malignancy tumor. Aside from radical tumor nephrectomy, treatment encompassed chemotherapy in all cases and radiotherapy in half of the patients according to the study protocol. In all, 32% of the children received preoperative treatment and 68% underwent primary…
Osseous fixation of a penile prosthesis after transsexual phalloplasty: a case report.
AbstractWe report on a patient who had undergone female-to-male transsexual surgery and subsequent phalloplasty by means of a free latissimus dorsi muscle graft with pudendal nerve coaptation elsewhere 10 years ago. The surgical strategy for implantation and osseous fixation of a penile prosthesis is described. We discuss whether the primary implantation of a penile prosthesis during 1-stage surgical phalloplasty is more advantageous in comparison with the currently favored secondary implantation. Phalloplasty should be represented by a 1-stage surgical procedure encompassing the creation of a neourethra, restoration of tactile and possibly erogenous sensibility, and implantation of a penil…
Genitourinary cancer in childhood
Sigma-rectum pouch (Mainz pouch II).
A substantial modification of the classic technique of ureterosigmoidostomy is introduced in this article. To date, this procedure has been used in 47 patients. This article reviews the surgical technique of the antemesenterial splitting of the intestine at the recto-sigmoid junction which creates a pouch by subsequent side-to-side anastomosis.
The Mainz Pouch II
The Mainz pouch II procedure has proved to be a substantial modification of the classical technique of ureterosigmoidostomy at many institutions. To date we have used this procedure in 72 patients, including 15 children. Detubularization causes a low pressure and eliminates high-pressure contractions. Without the risk of compromising the blood supply the pouch is fixed at the promontory which reduces the risk of ureteral kinking and upper urinary tract dilatation as it is sometimes observed after ureterosigmoidostomy. The technique is not only indicated in cases of failed ureterosigmoidostomy but also for primary urinary diversion. Of the 72 patients operated, all are evaluable with a follo…
Continent urinary diversion in childhood
Continence and a positive body image are important, especially to the adolescent patient. Since 1964 we have used ureterosigmoidostomy and have achieved a complete continence rate of 92.3%. The creation of a low-pressure reservoir by antimesenteric splitting of the recto-sigmoid eliminated many of the shortcomings of ureterosigmoidostomy. This procedure is termed the sigma-rectum pouch and has been applied in six children to date. Mainz-pouch bladder augmentation or substitution has been performed in 20 children, 17 of whom are completely continent. The results of the modified Young Dees procedure were disappointing. In three children, conversion into a continent diversion was necessary. Al…