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Developmental alterations in the fetal lamb bladder subjected to partial urethral obstruction in utero.

To identify the structural changes seen in the developing bladder subjected to outflow obstruction, a fetal lamb model was developed. With this model, which attempts to reproduce conditions such as those found in posterior urethral valves, quantitative biochemical parameters were used to evaluate the effects of partial outflow obstruction on detrusor cellularity and innervation in the developing bladder. Partial urethral obstruction was created in 9 fetal sheep (90 to 100 days gestation), 6 sham operated animals serving as controls. Fetuses were delivered at term and sacrificed. Bladders were removed and weighed. Mucosa free detrusor was assayed for DNA and choline acetyltransferase (ChAT) activity, indices of cell number and cholinergic innervation, respectively. In similar specimens of detrusor, cell ploidy and nuclear size were determined by flow cytometry and nuclear morphometry, respectively. The results showed that partial urethral obstruction in utero resulted in a significant increase in bladder weight (p < 0.05) and total detrusor DNA content (p < 0.01). With the increase in detrusor DNA content, there was a parallel increase in total detrusor ChAT activity. These results suggest that early development of the bladder is altered both on a cellular level (increase in cellularity) and a neural level (increase in cholinergic nerve density) under conditions of mechanical distension.

Animals↗

Congenital posterior urethral obstruction: the historical perspective.

The currently accepted interpretation of urethral anatomy and pathology in boys is based on studies from the first half of this century, most notably from Hugh Hampton Young and his colleagues. The studies that led to Young's conclusions and the developments in the management allow for reinterpretation, particularly with the advent of prenatal diagnosis and video-endoscopic recording technology.

Europe↗

A fetal lamb model of partial urethral obstruction: experimental protocol and results.

The functional effects of bladder outlet obstruction in the developing urinary tract are well recognized in patients born with posterior urethral valves, in whom a spectrum of bladder dysfunction has been described. To better understand the changes occurring in the partially obstructed developing lower urinary tract, a fetal lamb model of partial urethral obstruction was developed. Fetal lambs at 90 days' gestation underwent surgical placement of a silver ring (ex utero) at the level of the proximal bladder neck, with concomitant ligation of the urachus. Control animals underwent urethral ligation only. The lambs were then allowed to go through normal gestation, and ewes were delivered spontaneously. The animals were studied between 2 and 7 days after birth. The postmortem examination showed that the ring was just distal to the bladder neck, around the proximal urethra. This resulted in gradual, partial occlusion of the urethra. Bladder weights, bladder wall thickness, and bladder capacity were significantly increased in the partially obstructed animals as compared with the controls. There was little or no upper tract dilatation in the obstructed group. This animal model, the first to produce gradual outflow obstruction in the fetus, provides a reproducible model of partial urethral obstruction. The model can be used to assay the biochemical and physiological changes found in the developing urinary tract of fetal lambs submitted to intravesical obstruction.

Animals↗

Use of an implant for intraosseous infusion as supportive therapy for a Vietnamese pot-bellied pig with urethral obstruction caused by a polyp.

A Vietnamese pot-bellied pig with a urethral polyp was supported by total parenteral nutrition given through an intraosseous implant. Peripheral vascular access was difficult to establish and maintain in this anorectic pig, so a pediatric intraosseous implant was placed in the left tibia. Surgical repair of the urethra was not considered possible, and alternative techniques of a functional bypass were unacceptable to the owners, so euthanasia was elected. Histologic examination of the urethra revealed a polypoid structure believed to be similar to benign congenital polyps described in young boys.

Animals↗

Neodymium:Yttrium-aluminum-Garnet (Nd:YAG) laser ablation of an obstructive urethral polyp in a dog.

A miniature schnauzer presented for evaluation of a persistent lower urinary tract obstruction. Further examination revealed that the dog had developed an obstructive, inflammatory polyp secondary to a long-standing urinary tract infection. The polyp was located within the proximal urethra and interfered with normal voiding. The polyp was visualized using flexible endoscopy and then was successfully ablated using the neodymium:yttrium-aluminum-garnet (Nd:YAG) laser. The Nd:YAG laser is a potentially useful tool for treating various lesions of the lower urinary tract.

Animals↗

Evaluation of cervico-urethral obstruction with ambulatory pressure/flow studies: an alternative to conventional pressure/flow studies?

Most of the urodynamic studies are conducted in the laboratory during a brief recording time and under nonphysiological conditions and, thus, may fail to unfold the nature of existing pathological conditions of the lower urinary tract; false positives and false negatives are possible. To overcome some of the difficulties associated with conventional P/F studies we have developed, with the cooperation of Medical Measurement System company, Entschede, The Netherlands, a portable system (UDS 2000) for ambulatory monitoring of intravesical pressure, abdominal pressure and EMG connectable with a weight-transducer flowmeter that allows to perform Holter P/F measurements. We compared the results obtained with conventional P/F studies and with Holter P/F studies in 58 BPH patients. During the filling phase we observed a slightly increased number of stable detrusors with Holter P/F recording (46 vs 42); conversely, the number of patients suffering from urge incontinence was the same (7 pts). During the voiding phase, out of 45 patients considered obstructed at conventional P/F study, only 42 were really urodynamically obstructed (93.3%), while other 3 patients had bordeline obstruction. 4 patients with bordeline obstruction at conventional P/F study were considered non-obstructed after Holter P/F. In conclusion, Holter P/F proved to be reliable in the assessment of bladder function during storage and emptying in BPH patients and to be more specific in defining outlet obstruction than the conventional study because of the physiologic filling, the reduction of urethral irritation, the lack of a urethral catheter either during filling or voiding, and the reduction of emotional stress.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Endoscopic treatment of complete urethral obstruction using thin trocar.

We used an endoscopic thin trocar to reestablish the continuity of the completely obliterated urethra in 2 patients. In 1 man the obstruction resulted from a pelvic fracture and in 1 woman from early removal of the urethral catheter after a bladder neck reconstruction. We found this technique safe and effective, and we consider it to represent an improvement over previously described methods of endoscopic treatment of the obliterated urethra.

Adult↗