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Biomedical subjects

M A Keating

Publications and source records attributed to M A Keating.

At least 19 recordsLinked to original sources
PubMed1992

Managing apparent ureteropelvic junction obstruction in the newborn.

A total of 97 newborns with apparent ureteropelvic junction obstruction was evaluated from mid 1984 to 1989. Evaluation and management are described. Of these patients 39 with an affected kidney showing good initial differential function (greater than 35%) by diethylenetriaminepentaacetic acid scan and 2 showing diminished function (less than 35%) were followed nonoperatively. Six patients (15%) eventually required pyeloplasty for diminishing function (4), urinary tract infections (1) or symptoms of colic (1). The 4 patients with diminishing function improved after pyeloplasty to at least the initial level. A total of 12 patients with good initial function (greater than 35%) of the affected kidney underwent early pyeloplasty (within 6 weeks of diagnosis). They were compared to the similar group of patients managed nonoperatively and followed by sequential renal scans. Eventual changes in percentage differential function in the nonoperative and early surgery groups were +2.8% and +4.1%, respectively. Changes in extraction factor were +0.8% (nonoperative group) and +0.9% (surgery group). No statistically significant difference was found. In the kidney with apparent ureteropelvic junction obstruction and good function, an initial nonoperative approach with sequential renal scan followup and pyeloplasty as needed appears to be reasonable and has resulted in no permanent loss of function.

Follow-Up Studies↗
PubMed1992

Median raphe cysts of the genitalia.

We report 2 recent cases of midline cysts of the genitoperineal raphe in children, and discuss the embryogenesis, diagnosis and management. Congenital anomalies of an unclear etiology, median raphe cysts are probably more common than has been reported in the literature. Medical attention is usually sought for secondary infections or pain with intercourse. Awareness and prompt identification of these entities by urologists are essential for proper management when differentiation from other more formidable lesions, including urethral diverticula, becomes important. Simple surgical excision is effective in most cases.

Child↗
PubMed1991

True hermaphroditism: sonographic demonstration of ovotestes.

A 15-year-old boy with normal external genitalia presented with severe bilateral gynecomastia, intermittent painful scrotal swelling, and a recent history of scrotal trauma. Ultrasound (US) revealed testicles of normal size with diffusely heterogeneous echotexture due to scattered cysts. Ovotestes were found at surgery and pathologic examination. Bilateral partial gonadectomies were performed. Four months later he had testicular pain and swelling. US revealed bilateral multiseptate cystic masses. After repeat surgery, he is now free of symptoms. The diagnosis of true hermaphroditism and ovotestis should be considered in a phenotypic male adolescent with gynecomastia when testicular parenchyma is heterogeneous at US because of multiple scattered cysts.

Adolescent↗
PubMed1990

Low transurethral incision of single system intravesical ureteroceles in children.

Single system intravesical ureteroceles in children usually result in various degrees of hydroureteronephrosis requiring surgical intervention to provide drainage, decompression and preservation of renal function. Our experience with 7 symptomatic single system ureteroceles in 5 children managed by low transverse endoscopic ureterocele incision is reviewed. After endoscopic incision, hydroureteronephrosis decreased in all patients. Vesicoureteral reflux after incision was noted in only 1 kidney. The technique of short (2 to 3 mm.) low transverse ureterocele incision is recommended for the initial management of single system ureteroceles to relieve obstruction. Preservation of the flap valve ureteral antireflux mechanism is possible in most children. The technique is simply performed, can be safely done in the youngest child and, in many, obviates the need for a further operation.

Adolescent↗
PubMed1990

Ontogeny of bladder function in the rabbit.

Although numerous experimental studies have addressed urinary bladder innervation, physiology and pharmacology, little information is available concerning the ontogeny of bladder function. The present study describes the developmental aspects of bladder mass, bladder capacity, pressure development and emptying in white New Zealand rabbits one day of age through maturity (11 to 15 weeks of age). The following studies were performed: Cystometry, pressure generation, rate of pressure generation, and emptying responses to field stimulation, cholinergic and purinergic stimulation using the in vitro whole bladder model. The results of these studies can be summarized as follows: 1) body weight and bladder weight increased in proportion to each other, bladder capacity increase proportionally with development until eight weeks of age, then increased substantially greater than body and bladder weight between eight and 11 to 15 weeks of age; 2) the ability to empty is similar for all ages; 3) pressure responsiveness to field stimulation, bethanechol, and ATP is greater at one day? of age, intermediate at one week of age, and similar for the other age groups; 4) The response to ATP (purinergic transmitter) is of an equal magnitude to the cholinergic response at one day, and reduces rapidly to approximately 45% of the cholinergic response by four weeks. Desensitization of the bladders to ATP reduced the response to field stimulation in the one day bladders to a significantly greater degree than the other age groups. These functional results indicate a marked alteration in cholinergic and purinergic response between the one day and the four week old rabbit bladders, with the response of the one week old bladders in between. The responses of the four, eight, and 11 to 15 week bladders was similar for equal volumes even though the bladder mass increased over threefold. This indicates that the ability of the bladder to generate pressure (during development) is not directly related to bladder mass.

Adenosine Triphosphate↗
PubMed1990

Preservation of the urethral plate in hypospadias repair: extended applications and further experience with the onlay island flap urethroplasty.

The onlay island flap urethroplasty, a variant of the transverse preputial (tubularized) island flap, was originally described for repair of anterior hypospadias. However, many cases of mid and proximal hypospadias have a well developed urethral plate and exhibit little or no chordee after release of skin tethering. Patients with this combination of findings are ideal candidates for onlay island flap urethroplasty regardless of initial meatal position. During the last 5 years the onlay island flap has been used for repair of mid to posterior hypospadias in 31 patients (38% of the cases). These are variants that formerly would have required more extensive urethroplasty. Because of the technical advantages of the onlay island flap this alteration in technique selection has resulted in fewer complications. When applied to mid and posterior hypospadias the onlay island flap maintained a significantly lower complication rate (10%) compared to other standard techniques. Preservation of the urethral plate in hypospadias repair is a principle with significant implications to an extended variety of hypospadias.

Humans↗
PubMed1990

Management of the dilated obstructed ureter.

Megaureters have been classified as refluxing, obstructed, nonrefluxing-nonobstructed, and refluxing-obstructed. The recommendations for the management of each type are fairly well agreed on. Where controversy has arisen is in the differentiation of the types, especially the primary obstructed from the nonrefluxing-nonobstructed. Distinguishing dilatations that represent significant obstruction from those that apparently are anatomic variants having no detrimental implications for renal function is no simple task, especially in the neonatal infant.

Dilatation, Pathologic↗
PubMed1989

Long-term experience with flutamide in patients with prostatic carcinoma.

Fifty-two patients with previously untreated metastatic carcinoma of the prostate were treated with flutamide 250 mg tid. Response was classified according to objective and subjective criteria, and duration of response and total survival were chosen as endpoints. Disease manifestations at presentation and tumor burden were studied to determine their relationship, if any, to treatment response and outcome. Total survival was longest in 26 patients who had objective responses (mean 50 months). Patients who failed to respond (n = 13) and those who had subjective responses (n = 13) survived an average of eleven and 17.2 months, respectively. Tumor burden was correlated with response to treatment and total survival; those judged to have a minimum tumor burden had objective responses and survived an average of sixty months. Sixteen other patients who had been previously treated with diethylstilbestrol were also studied. Nine of these had cardiovascular complications while taking diethylstilbestrol, and tolerated flutamide without further complications. Those in remission stayed in remission, and sexual potency returned to 5 patients.

Adenocarcinoma↗
PubMed1989

Postnatal testicular maldevelopment in unilateral cryptorchidism.

Histomorphometric analysis of semi-thin sections was performed on testicular biopsies of 232 unilaterally cryptorchid testes and 195 of their contralateral descended partners. The results demonstrated a decreased number of germ cells detectable from the first year of life. There was delayed and defective transformation of gonocytes to Ad spermatogonia, which normally is complete at age 6 months, delayed or failed transformation of Ad spermatogonia to primary spermatocytes, which normally commences at age 3 years and decreased numbers of Leydig cells. These abnormalities were present in the unilaterally cryptorchid testes and their contralateral descended partners but they were more severe, of earlier onset and more progressive in the cryptorchid testes. These findings are compatible with the hypothesis that hypogonadotropic hypogonadism is the cause of the increased incidence of infertility seen in unilateral cryptorchidism.

Biopsy↗
PubMed1989

Cryptorchidism, orchiopexy and infertility: a critical long-term retrospective analysis.

We assessed the fertility of 40 patients who underwent orchiopexy between 1950 and 1960. Testicular biopsies also had been performed at operation, a practice exceptional for the era. Of 23 patients with unilateral undescended testes who attempted to have children 20 (87 per cent) were successful. In contrast, only 3 (33 per cent) of 9 patients with bilateral undescended testes fathered children. Over-all sperm counts in 16 patients were low but they were not predictive of paternity. Testicular biopsy specimens were reviewed and the fertility index was determined. In most cases a good correlation was found between histological status and paternity status.

Adult↗
PubMed1989

Changing concepts in management of primary obstructive megaureter.

The management of neonatal urinary tract dilatations represents one of the most challenging dilemmas in pediatric urology today. We have been confronted with 44 renal units in 35 neonates diagnosed as having primary obstructive megaureter during the last 6 years. Of these units 23 in 17 infants were diagnosed antenatally and 20 (87 per cent) have been managed without surgical intervention. Notably, 16 renal units were graded as moderate to severe megaureters by an excretory urogram. The decision to manage conservatively was based on the initial extraction of the 99mdiethylenetriaminepentaacetic acid renal scan (the extraction factor). This estimate of absolute renal function has been used to differentiate dilatations with obstructive implications for the renal parenchyma from those without. Significantly, expectant treatment has resulted in improvement of dilatation on sequential excretory urograms in 15 megaureters and none has shown a deterioration of function by renal scan. Similar diagnostic criterion also has resulted in conservative management for 12 of 21 additional neonatal megaureters seen during this period with symptoms or they were discovered serendipitously. Only 2 of these 12 megaureters required surgical correction. The neonatal primary megaureter appears in many cases to represent a different entity than those that commonly presented before the advent of antenatal and perinatal diagnosis.

Dilatation, Pathologic↗
PubMed1989

Hinging the urethral plate in hypospadias meatoplasty.

A technique is described for creation of a cosmetically normal, vertical slit-like urethral meatus in conjunction with common hypospadias reconstructions that preserve the urethral plate. The distal portion of the urethral plate is incised longitudinally in the midline. This incision allows the flat and rigid urethral plate to be folded or hinged during glans plasty, molding it into an anatomically correct vertical slit configuration. This modification has been applied successfully to a variety of meatal-based flap and onlay island flap urethroplasties with no increased morbidity and a significant improvement in meatal cosmetic results.

Epithelium↗
PubMed1989

Continent urinary reconstruction in ischiopagus tripus conjoined twins.

The principle of the continent urinary reservoir involves use of a variety of intestinal segments providing continence, a mechanism of antireflux and a catheterizable stoma in either an abdominal or pelvic location. This concept was used to create a continent urinary reservoir in a 3-year-old former ischiopagus tripus conjoined twin. The solitary renal unit had been drained into a hydrocolpos with an antirefluxing ureteral reimplantation at separation. The patient remained incontinent through the urogenital sinus. At subsequent reconstruction the posterior aspect of the hydrocolpos was tubularized as a vagina, while the remainder of the hydrocolpos was augmented with ileum to create a urinary reservoir. The conduit was constructed with imbricated ileum, in which myectomy had been performed to allow for easier imbrication and tubularization for a narrow neourethra. A second set of conjoined twins have been separated similarly. Of these twins 1 will undergo creation of a continent urinary reservoir in an identical fashion. This represents the first report of the use of hydrocolpos in the creation of a urinary reservoir.

Child, Preschool↗
PubMed1989

Urological manifestations of the popliteal pterygium syndrome.

We report a case of the popliteal pterygium syndrome resulting in abnormalities of the external genitalia and testicular ectopia. Management included bilateral orchiopexy and complex genitoplasty. Pterygia represent errors in development that manifest as webs across joints and can result in anomalies of the external genitalia. The genitourinary aspects of the popliteal pterygium syndrome and their management are discussed.

Abnormalities, Multiple↗
PubMed1989

Development of elastic fibres in the upper urinary tract.

The development of elastic fibres in the upper urinary tract was studied in 31 fetuses ranging in ovulatory age from 10 to 24 weeks using special staining techniques for elastic fibres. The number, orientation and distribution of elastic fibres are described and correlated with age, ureteric level, and fetal weight. Significantly, before 10 weeks, elastic fibres were few in number, poorly developed, and randomly arranged. After 12 weeks, these fibres became more numerous at each level of the urinary tract, and were seen to develop specific orientation. The findings are described and potential clinical implications are discussed.

Elastic Tissue↗
PubMed1989

Technical challenge of the megameatus intact prepuce hypospadias variant: the pyramid procedure.

An unusual variant of hypospadias is the focus of this report. This distal variant consists of a megameatus and urethra in the presence of intact foreskin. Recognition is important, not only because of the uncommon combination of findings, which run contrary to the classical presentation of most hypospadias, but also because of the technical shortcomings that are encountered during repair with standard techniques. The pyramid procedure is described, which allows for an end-on dissection of the distal megameatus-urethra, enabling a reduction in caliber of both while facilitating remodeling of the glans. The procedure has proved to be successful and reliable for this particular hypospadias variant. No complications have been encountered.

Circumcision, Male↗