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Biomedical subjects

R A Mevorach

Publications and source records attributed to R A Mevorach.

32 records · Page 2Linked to original sources
PubMed1994

Renal hemodynamic and functional effects of 10 days' partial urinary obstruction in the fetal lamb.

We studied fetal lambs to define the renal pathophysiology of chronic in utero partial bladder outlet obstruction. These fetal lambs, 115 to 120 days gestation (term = 145 days), underwent urethral ligation, placement of a urachal catheter and positioning of an ultrasonic flow transducer around the left renal artery. Partial obstruction was created by placing a narrow connector between the urachal and an amniotic catheter. In control animals a large connector was placed to allow free drainage of the bladder into the amniotic cavity. Renal blood flow was measured daily, and urine was collected at days 5 and 10 to evaluate renal function. In control animals, no significant changes in any parameters were observed. In the partially obstructed fetal lambs, renal blood flow increased to 165% of baseline after 5 days; from 5 to 10 days, it decreased, but remained above baseline values through 10 days (128%). Urine production dropped significantly after 10 days (67%). Glomerular filtration rate increased slightly after 5 days (127%), but decreased after 10 (56%). Filtration fraction steadily decreased after 5 (70%) and 10 days (33%). Fractional and total sodium excretion did not change. Renal blood flow increases, filtration fraction decreases and renal function trends progressively diminish in response to partial bladder outlet obstruction over a period of 10 days in the fetal lamb.

Animals↗
PubMed1994

Pediatric ureteropelvic junction obstruction treated with retrograde endopyelotomy.

OBJECTIVES: To determine the feasibility of retrograde endopyelotomy in the management of pediatric ureteropelvic junction (UPJ) obstruction. METHODS: We treated 2 boys aged 4 and 6 years with the Acucise endopyelotomy device for symptomatic ureteropelvic junction obstruction. The Acucise device was placed over a Lunderquist guide wire with fluoroscopic guidance only and routine Double J catheters were left in situ for 6 weeks after the procedure. The morbidity of the treatment and the short-term outcome were assessed. RESULTS: There were no acute complications and short-term follow-up results were satisfactory as determined by intravenous urography and diuretic renography. CONCLUSIONS: Ureteropelvic junction obstruction in children may be treated by retrograde endopyelotomy with the Acucise device. The principal potential advantage of this procedure is reduced morbidity. Our findings suggest that further evaluation is warranted.

Catheterization↗
PubMed1994

Urodynamic and clinical follow-up of 28 children after gastrocystoplasty.

OBJECTIVES: To determine the efficacy of gastrocystoplasty in creating a large and compliant urinary reservoir. PATIENTS AND METHODS: Twenty-eight children (14 boys, 14 girls), with a median age of 9 years (range 4-17), were evaluated before and for a median of 2 years and 5 months after gastrocystoplasty. Evaluation included urodynamic and renal function studies and a survey of their post-operative complications and their sense of well-being. Renal function was assessed by ultrasound and serum creatinine, and electrolytes were measured. RESULTS: After gastrocystoplasty bladder size increased, compliance improved, hydronephrosis decreased or was stable, and renal function remained stable. There were minimal complications and the children's subjective impression of their well-being was markedly improved. CONCLUSION: Gastrocystoplasty, using our surgical technique, is a reliable method of creating a large and compliant urinary reservoir. Advantages include the absence of clinical urinary tract infections, the absence of mucus and the preservation of renal function. Complications, such as haematuria, dysuria and hypochloraemic alkalosis, might be avoided by excluding the antrum from the gastrocystoplasty, maintaining the child on a normal salt-containing diet, employing catheterization or buffering the urine in children with normal urethral sensation.

Adolescent↗
PubMed1993

Therapeutic laparoscopy for intra-abdominal testes.

Fourteen laparoscopic surgical procedures were performed in 10 children with 11 intra-abdominal testes. In addition to localizing the testes, laparoscopy aided in the surgical approach. In 8 patients, the first phase of a two-stage Fowler-Stephens orchiopexy was performed. Five children underwent an open surgical procedure three months later and have a viable testis in the scrotum after at least nine months of follow-up. In 5 patients (6 testicles), laparoscopy was used to dissect the testis. Three patients underwent the second phase of the two-stage Fowler-Stephens procedure laparoscopically. In all 3 patients, the testicle could be easily mobilized into the scrotum. Two other testicles were mobilized by dissecting the spermatic vessels up to the renal hilum laparoscopically; this allowed the intra-abdominal testes to come into the scrotum without dividing the spermatic vessels. In one teenager with a small intra-abdominal testis and a normal contralateral testis, laparoscopic orchiectomy was performed. We believe laparoscopy has a role both diagnostically and surgically in the treatment of intra-abdominal testes.

Adolescent↗
PubMed1993

Effects of endothelium-derived nitric oxide on renal hemodynamics and function in the sheep fetus.

We investigated the effects of the endothelium-derived nitric oxide system on renal hemodynamics and function during the 3rd trimester in a chronically catheterized fetal sheep preparation. Acetylcholine caused a significant decrease in renal vascular resistance (60% of the baseline value) as compared with aortic constriction (142% of the baseline value). The effects of acetylcholine could be blocked by prior administration of N omega-nitro-L-arginine (renal vascular resistance = 102% of baseline). Sodium nitroprusside also caused a significant drop in renal vascular resistance (63% of baseline), but this could not be blocked by N omega-nitro-L-arginine (77% of baseline). Infusion of N omega-nitro-L-arginine with blood pressure maintained at a constant level resulted in a significant increase in renal vascular resistance (148% of the baseline value) as compared with saline alone (94% of baseline). Glomerular filtration rate increased after saline infusion (156% of the baseline value), but this increase was blocked by N omega-nitro-L-arginine (87% of baseline). Sodium excretion also increased (340%), and this increase was blunted by N omega-nitro-L-arginine (235%). We conclude that basal production of endothelium-derived nitric oxide results in ongoing renal vasodilation in 3rd-trimester fetal sheep, maintaining baseline renal blood flow. The endothelium-derived nitric oxide system can also be stimulated to an increased level of activity, and its blockade partially prevents the homeostatic response of the fetus to volume and salt overload.

Animals↗
PubMed1992

Renal cell carcinoma: incidental diagnosis and natural history: review of 235 cases.

Two hundred thirty-five cases of histologically proved renal cell carcinoma (1976-1987) were reviewed to determine the impact of incidental tumor detection on the natural history of this cancer. One hundred sixty-eight patients (71.5%) presented with clinical signs and/or symptoms of renal pathology. Of these, 25 (18%) were investigated without consideration of renal cell carcinoma in the differential diagnosis. Sixty-seven cases (28.5%) were diagnosed as an incidental finding on diagnostic imaging for extrarenal symptomatology. Approximately 30 percent of patients were found to have metastatic disease on initial presentation regardless of incidental, or suspected discovery of these tumors. Stages A and B tumors were encountered with equal frequency in patient groups with both suspected and incidental diagnosis. Intravenous pyelography was the diagnostic modality used to detect the diagnosis in 83 percent of cases. While incidental detection of renal cell carcinoma has become more frequent than in previous years, it appears to have impacted minimally on the discovery of earlier stage tumors than those with presenting clinical symptoms. In contrast to prior reports, our data show that the natural history of renal cell carcinoma is not significantly altered by the incidental detection of tumor.

Carcinoma, Renal Cell↗
PubMed1992

Perforation and intravesical erosion of a ventriculoperitoneal shunt in a child with an augmentation cystoplasty.

Bladder augmentation has evolved into a common method of management in children with a low capacity and/or poorly compliant bladder secondary to a neuropathic condition. We report on a 4-year-old girl with myelodysplasia who presented with sepsis and who had a perforation of the augmented bladder, which was surgically repaired. She returned for evaluation 1 month after she was discharged from the hospital when the distal component of the ventriculoperitoneal shunt was noted to protrude per urethram after clean catheterization. Distal shunt replacement with prolonged bladder drainage successfully resolved this perforation of the augmented bladder. The patient has had no further difficulties. We discuss the diagnosis and management of this case with reference to the current literature regarding complications of augmentation cystoplasty.

Cerebrospinal Fluid Shunts↗
PubMed1991

Color Doppler ultrasound compared to a radionuclide scanning of spermatic cord torsion in a canine model.

High resolution color doppler ultrasound can simultaneously display blood flow superimposed on detailed gray scale anatomic images. Using a single-blind study design, nine adult male dogs underwent intravaginal spermatic cord torsion and subsequent evaluation with technetium 99M-pertechnetate radionuclide, and color doppler ultrasound imaging techniques. Torsions of 90 to 720 degrees were created surgically, followed by examination with each modality at one hour (four animals), and four hours (five animals) following the procedure. Testicular torsion was diagnosed if perfusion was absent or markedly diminished on color doppler imaging or radionuclide scan. In all cases of 360 degrees or greater, torsion was diagnosed by either modality at both one and four hour time delays. If observers did not diagnose torsion, they were asked to assess the relative testicular perfusion. Color doppler ultrasound and radionuclide scanning were without error in correctly detecting a relative decrease in perfusion in each of these instances. Furthermore, color doppler imaging with spectral analysis was able to detect an enhancement of the diastolic component of the arterial signal at 180 degrees of torsion. This spectral pattern coupled with a relative decrease in blood flow allowed presumptive diagnosis at one hour of partial torsion that was subsequently apparent as absent perfusion only after 4 hours on radionuclide and repeat color doppler ultrasound. Color doppler ultrasound proved to be superior to radionuclide scanning in detecting diminished perfusion in this experiment. The detailed information provided by spectral and anatomic display with color doppler ultrasound recommends it for the evaluation of acute scrotal pathology of uncertain etiology.

Animals↗
PubMed1991

Testicular imaging.

Clinicians have relied on radionuclide scanning for evaluating acute scrotal pain and on ultrasonography for chronic scrotal pain and anatomic lesions (testicular and paratesticular structures). This review reinforces the utility of these established imaging techniques and also introduces color Doppler ultrasonography as an integral component in the advancement of testicular imaging, particularly in effective and timely diagnosis of spermatic cord torsion. The expanding capability of MR imaging for scrotal disorders is presented.

Color↗
PubMed1990

Human papillomavirus type 6 in grade I transitional cell carcinoma of the urethra.

Of 4 patients who underwent cystourethroscopy, biopsy and laser excision of suspected urethral condylomata acuminata 3 had coexistent grade I papillary transitional cell carcinoma of the urethra. Human papillomavirus type 6 messenger ribonucleic acid was demonstrated within biopsy specimens using tritium-labeled single-stranded antisense ribonucleic acid probes. Compared to condylomata the papillary transitional epithelium expressed less viral message, which might be expected in an epithelium that does not show full squamous epithelial or koilocytotic differentiation. Among these patients there was 1 papillary transitional lesion in the bladder that, although histologically similar, did not express human papillomavirus message, suggesting differential susceptibility of epithelium between the bladder and urethra. The finding of active human papillomavirus transcription within the urethral papillary transitional lesions raises the possibility of an active role for the virus in the pathogenesis of these lesions. These findings broaden the spectrum of epithelial types reported to support human papillomaviruses and provides impetus for a wider search for these viruses in other transitional cell neoplasms.

Adult↗
PubMed1990

Color Doppler US in the evaluation of acute scrotal disease.

Twenty-seven patients presented with painful acute scrotal swelling. After a clinical impression was established, all patients underwent diagnostic imaging with color Doppler ultrasound (US). Seven patients underwent surgical exploration for testicular torsion diagnosed with color Doppler US (100% operative confirmation), one underwent radical orchiectomy for treatment of seminoma, and one underwent orchidopexy for treatment of a freely mobile testis. Eighteen patients were treated for nonoperable conditions. Diagnoses made with color Doppler US correlated with final clinical diagnoses in all patients. In 10 of 27 patients (38%), the diagnosis was established at color Doppler US. Until now, nuclear scanning has had a paramount role in the evaluation of equivocal cases of acute scrotal disease. Results show that color Doppler US helps accurately correlate anatomy and perfusion in real time and may prove to be the definitive imaging technique for the diagnostic evaluation of acute scrotal pain or swelling.

Acute Disease↗
PubMed1986

Testicular abscess: diagnosis by ultrasonography.

We reviewed 8 cases of surgically proved testicular abscess with emphasis upon the ultrasonographic findings. The images were correlated with testicular anatomy and the pathological findings of abscess formation. In 3 of 8 patients undergoing serial high resolution ultrasound examinations a consistent pattern of testicular abscess was present 1 to 7 weeks preoperatively. In the remaining 5 patients preoperative ultrasound documented the presence of abscess. Recognition of the ultrasonographic appearance of testicular abscess should permit expedient surgical intervention.

Abscess↗