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Biomedical subjects

B A Kogan

Publications and source records attributed to B A Kogan.

At least 55 records · Page 3Linked to original sources
PubMed1996

Lower urinary tract function in ambulatory children with spina bifida.

OBJECTIVE: To investigate lower urinary tract function in ambulatory children with myelomeningocele. PATIENTS AND METHODS: The urological course of 45 children with myelomeningocele who walked either independently (19 children) or with ankle-foot orthotics (26 children) was reviewed. Follow-up ranged from 9 months to 13.5 years (mean 4.75 years). RESULTS: A normal pattern of voiding was observed both clinically and during urodynamic evaluation in only three of the 45 children, with the remainder displaying neurogenic lower urinary tract dysfunction. The independent walkers and those with orthotics did not differ in the spectrum of lower urinary tract dysfunction or other variables. Those patients with persistent incontinence underwent an initial urodynamic evaluation when older (mean 3.7 years versus 6.4 weeks in those who were continent). CONCLUSION: Ambulatory children with myelomeningocele suffer the full spectrum of lower urinary tract dysfunction. Given the potential danger of untreated lower urinary tract dysfunction, ambulatory children with myelomeningocele should receive the same diagnostic and therapeutic attention as their peers with more overt neurological deficits.

Adolescent↗
PubMed1996

Efficacy of retrograde endopyelotomy in children.

PURPOSE: Endopyelotomy has been performed extensively in adults for the treatment of ureteropelvic junction obstruction. To determine its applicability to the pediatric population we reviewed our experience with retrograde endopyelotomy in children. MATERIALS AND METHODS: Eight children 4 to 15 years old were treated with retrograde endopyelotomy and results were compared to those of a concurrent group of 8 treated with open pyeloureteroplasty. RESULTS: Retrograde endopyelotomy was done in all of our patients with lower ureteral dilatation (as an adjunct measure in 5). Seven patients had symptomatic and radiographic improvement. The patient in whom the procedure failed had a crossing lower pole vessel. Postoperative analgesia, length of hospitalization and cost were lower in the endopyelotomy group. CONCLUSIONS: Retrograde endopyelotomy is feasible in children older than age 4 years and it results in reduced morbidity. The success rate is high but open surgery remains the standard, particularly when a crossing lower pole vessel is identified preoperatively.

Adolescent↗
PubMed1996

The effect of prepubertal androgen exposure on adult penile length.

PURPOSE: Recent studies in the rat suggest that early exposure to exogenous testosterone accelerates the loss of androgen receptors and compromises eventual penile length. To determine whether this is true in men we measured adult penile length of patients treated in childhood for sexual precocity. MATERIALS AND METHODS: We examined 21 men with sexual precocity due to true precocious puberty (12) or congenital adrenal hyperplasia (9) who had been followed at our institution since childhood. Penile lengths were compared with data from normal men. RESULTS: Mean stretched penile length plus or minus standard deviation was 12.7 +/- 2.6 cm. in all patients, 12.1 +/- 2.6 cm. in those with true precocious puberty and 13.6 +/- 1.6 cm. in those with congenital adrenal hyperplasia. These lengths were not significantly different from those of normal men (12.4 +/- 2.7 cm.). CONCLUSIONS: In contrast to findings in rats, exposure to endogenous testosterone during gestation and/or childhood does not reduce adult penile length in men. Thus, the use of testosterone to treat childhood genitourinary anomalies would likely not compromise mature penile size.

Adrenal Hyperplasia, Congenital↗
PubMed1996

Exogenous endothelin-1 causes renal vasodilation in the fetal lamb.

PURPOSE: Endothelin-1 is known to be a potent vasoconstrictor. We investigated the effects and mechanisms of action of endothelin-1 and its receptors in regulating renal vascular tone in the fetal lamb. MATERIALS AND METHODS: We observed the in vivo effects of endothelin-1, an endothelin-b receptor agonist (4-alanine-endothelin-1), endothelin-a receptor antagonists (BQ-610 and BQ-123), and the inhibition of prostaglandin and nitric oxide synthesis on the response of the renal circulation to endothelin-1 in a chronic preparation in third trimester fetal lambs. RESULTS: After injection of 250 ng./kg. endothelin-1 into the descending aorta proximal to the renal arteries in 8 fetal animals, renal blood flow increased (4.4 +/- 0.7 ml. per minute per kg., p < 0.001 versus vehicle), as did mean arterial blood pressure (3.0 +/- 0.3 mm. Hg,p < 0.001 versus vehicle). Calculated renal vascular resistance decreased (-1.1 +/- 0.2 mm. Hg per minute per kg./ml., p < 0.001 versus vehicle). After injection of 1,725 ng./kg. 4-alanine-endothelin-1 in 5 animals renal blood flow increased (3.8 +/- 0.4 ml. per minute per kg., p < 0.05 versus vehicle) and mean arterial blood pressure was unchanged (1.6 +/- 1.7 mm. Hg). Calculated renal vascular resistance decreased (-0.8 +/- 0.2 mm. Hg per minute per kg./ml., p < 0.05 versus vehicle). After injection of 0.5 mg./kg. BQ-610 in 6 animals renal blood flow increased (2.3 +/- 0.7 ml. per minute per kg., p < 0.05) and mean arterial blood pressure decreased (-2.7 +/- 0.3 mm. Hg, p < 0.05 versus vehicle). Calculated renal vascular resistance decreased but this difference was not statistically significant (-0.7 +/- 0.3 mm. Hg per minute per kg./ml., p < 0.07). A dose of 1 mg./kg. BQ-123 in 2 animals decreased renal vascular resistance markedly. Infusion of a prostaglandin synthesis inhibitor (1 mg./kg. per minute meclofenamic acid) did not alter the decrease in renal vascular resistance after endothelin-1 (-0.7 +/- 0.4 mm. Hg per minute per kg./ml). In contrast, during infusion of a nitric oxide synthesis inhibitor (1.5 mg./kg. per minute N-omega-nitro-L-arginine) endothelin-1 increased renal vascular resistance (1.2 +/- 0.2 mm. Hg per minute per kg./ml., p < 0.001). CONCLUSIONS: Endothelin-1 is a vasodilator in the fetal renal circulation, which acts primarily via endothelin-b receptors. Ongoing activity of endothelin-a receptors contributes to renal vascular tone in fetal lambs. The vasodilatory effects of endothelin-1 in the fetal lamb renal circulation are mediated via the nitric oxide system and not via prostanoids.

Animals↗
PubMed1996

Clean intermittent catheterization in boys using the LoFric catheter.

PURPOSE: We compared a recently developed hydrophilic catheter to the standard polyethylene catheter in regard to hematuria, infection and patient satisfaction. MATERIALS AND METHODS: A hydrophilic LoFric or standard Mentor catheter was assigned at random to 17 and 16 boys, respectively, who were skilled in intermittent self-catheterization. They were evaluated by weekly urinalysis and a questionnaire. RESULTS: Significantly fewer episodes of microscopic hematuria occurred in the LoFric than Mentor catheter group (9 episodes in 6 subjects versus 19 episodes in 11, p < 0.05). There were also fewer episodes of bacteriuria in the LoFric group but the difference was not statistically significant. Mean scores plus or minus standard deviation on a visual analogue scale with 0 equal to most and 10 equal to least favorable were LoFric 3.3 +/- 2.8 versus Mentor 4.9 +/- 2.7 for catheter convenience and 2.7 +/- 2.4 versus 4.2 +/- 2.6 for insertion comfort, significantly favoring the LoFric group (p < 0.05 for both). Of the 16 LoFric subjects 13 preferred to continue its use, particularly those with a history of urethral trauma or sphincteric spasm. CONCLUSIONS: In boys the LoFric catheter appears to cause less trauma. Although it is not reusable and is more expensive than the standard catheter, satisfaction is higher with the LoFric device and for select patients it has significant advantages.

Adolescent↗
PubMed1996

Therapeutic laparoscopy for the nonpalpable testicle.

Laparoscopy is playing an increasingly important role in the management of boys with nonpalpable testes. We describe our technique of laparoscopy and laparoscopically assisted orchidopexy. Our early results in 24 patients with nonpalpable intraabdominal testes have encouraged us to recommend this option as the procedure of choice.

Anesthesia, General↗
PubMed1995

Urine concentration and enuresis in healthy preschool children.

OBJECTIVES: To determine whether children concentrate their urine overnight and to assess the correlation between specific gravity of a first morning urine specimen and the results of a questionnaire concerning bedwetting, voiding habits, and continence in 47 healthy children aged 3 to 6 years. DESIGN: A prospective observer-blinded consecutive sample. SETTING: Two San Francisco, Calif., preschools. PARTICIPANTS: Forty-seven children attending preschool during the study period. MEASUREMENTS/MAIN RESULTS: Forty of 47 children had a urine specific gravity greater than 1.020. None of these children wet the bed during this study, although four (11%) of 36 had a history of bedwetting. Furthermore, seven children with a urine specific gravity of 1.015 or lower had a history of bedwetting and wet the bed during this study. A voiding frequency of six or more times per day, by history, was associated with a 3:1 relative risk of bedwetting but did not segregate children with primary enuresis from those with secondary enuresis. CONCLUSIONS: Our results indicate that healthy children aged 3 to 6 years are able to concentrate their urine. In addition, urine specific gravity was an accurate predictor of the presence of nocturnal enuresis in this group of children. Our results suggest that a specific gravity of the first morning urine specimen should be correlated with appropriate history before extensive diagnostic evaluation or empiric therapy is performed in children with nocturnal enuresis.

Child↗
PubMed1995

Fetal lower urinary tract physiology: in vivo studies.

Fetal lower urinary tract function is under continuous maturation throughout gestation and is an integrated neurophysiologic event by late gestation. Preliminary in vivo study suggests that peripheral and central nervous system regulation of micturition occurs in utero, and that these events can be modulated pharmacologically and through external stimulation. Normal bladder function in utero is essential to normal development of the entire fetus, and in utero modulation of bladder dysfunction may be feasible as our understanding and diagnostic acumen increase.

Animals↗
PubMed1995

The prune-belly syndrome: current insights.

The prune-belly syndrome comprises a constellation of well-established physical findings, yet the cause and management remain controversial. This review focuses on the current understanding of its pathogenesis and characterizes the fetal and neonatal diagnosis and management. Other associated anomalies are discussed to understand better the factors affecting treatment and prognosis as these patients grow into childhood and beyond.

Adult↗
PubMed1995

Recurrent Staphylococcus aureus renal abscess in a child positive for the human immunodeficiency virus.

A 10-year-old girl with the human immunodeficiency virus was found to have a Staphylococcus aureus renal abscess with perinephric extension. The abscess was drained first percutaneously and then surgically, and the patient received a 6-week course of intravenous antibiotics. Three months later, the abscess recurred, necessitating a nephrectomy. The extended morbidity and difficulty of eradicating S aureus suggest that, in immunocompromised patients, early aggressive surgical management is indicated.

AIDS-Related Opportunistic Infections↗
PubMed1995

Magnetic resonance imaging of vascular lesions of the scrotum and penis.

We report 2 rare cases of vascular lesions in the scrotum and penis: an arteriovenous malformation in a young man and a lymphohemangioma in a boy. Both patients had undergone previous treatment and had recurrent lesions. Magnetic resonance imaging was performed preoperatively for detailed information regarding lesion extent and involvement of adjacent structures.

Adolescent↗
PubMed1995

Renal preservation despite 35 days of partial bladder obstruction in the fetal lamb.

To determine whether the increase in renal blood flow and preservation of renal function that we demonstrated after 10 days of chronic partial bladder obstruction in the third trimester fetal lamb also occur after earlier longer obstruction, we modified our preparation and studied the effects of 35 days of obstruction begun during the second trimester. Partial bladder obstruction was created in 10 fetal lambs at 90 days of gestation (term equals 147 days). At repeat surgical intervention 28 days later vascular catheters and a left renal artery flow transducer were placed, and catheters were externalized. We then studied renal blood flow and function at gestational ages 120 days and 125 days after 30 days and 35 days of obstruction, respectively. Tissue was obtained for histology at the time of sacrifice. Eight control fetal lambs without obstruction were studied in a similar way. Bilateral hydroureteronephrosis was noted in all fetal lambs after partial obstruction, whereas the kidneys and bladders of the control animals had a normal appearance. Renal blood flow was higher in the obstructed fetal lambs than in controls (20.2 +/- 4.9 versus 10.2 +/- 0.9 ml. per minute per kg., p < 0.05 after 30 days and 17.1 +/- 2.7 versus 9.7 +/- 0.9 per minute per kg., p < 0.05 after 35 days). There was no evidence of decreased renal function by any parameter and, in fact, glomerular filtration rate and urine volume were increased after 30 days of obstruction (1.59 +/- 0.32 versus 0.69 +/- 0.07 ml. per minute per kg., p < 0.05 and 15.7 +/- 4.3 versus 5.2 +/- 0.8 ml. per hour per kg., p < 0.05, respectively). Histological studies demonstrated normal architecture of the kidneys but thinned cortex. We conclude that the physiological responses of the fetus are such that partial lower urinary tract obstruction in our preparation results in a prolonged increase in renal blood flow and preservation of renal function.

Animals↗
PubMed1995

Contradictory renal function measured with mercaptoacetyltriglycine diuretic renography in unilateral hydronephrosis.

PURPOSE: We studied apparently supranormal renal function in hydronephrotic kidneys, as measured by 99mtechnetium mercaptoacetyltriglycine renography. MATERIALS AND METHODS: We retrospectively reviewed the clinical history, ultrasonography and renography of 29 children. RESULTS: Of the 29 children 7 had greater than 50% relative function in the hydronephrotic kidney. This finding was independent of patient age, gender, degree of hydronephrosis or obstructive pattern. Of these 7 cases 6 occurred on the right side (p < 0.05 versus a large registry). CONCLUSIONS: In most cases supranormal renal function is caused by a technical problem, likely the inadequate background subtraction of mercaptoacetyltriglycine in the liver.

Child↗
PubMed1995

The physiology of gastrocystoplasty: once a stomach, always a stomach.

To determine the physiology of acid secretion after gastrocystoplasty with the body of the stomach we performed a prospective standardized 3-day study in 13 children (median age 12.5 years) who had undergone bladder augmentation/replacement (median postoperative period 2 years). Urinary pH and titratable acid, and serum gastrin levels were measured after gastric distention with a meal and bladder distention with urethral filling at baseline and after medication with a histamine-2 receptor antagonist or an anticholinergic agent. Five children underwent cystoscopy and biopsy of the gastric and native segments of the gastrocystoplasty. In the fasting state pH was neutral, there was no titratable acid in the urine and serum gastrin level was normal in all cases. After a meal urinary acid secretion and serum gastrin level increased markedly. After each medication half of the patients demonstrated marked inhibition of urinary acid secretion after a meal while response was partial in the remainder. In none of the patients was there significant alteration in the pattern of gastrin secretion. Bladder distention did not result in urinary acid secretion or gastrin secretion. The cystoscopic and histological appearance of the native bladder and stomach segment of the gastrocystoplasty in the 5 patients was normal. We conclude that the gastric body segment used in gastrocystoplasty continues to secrete acid as though it were part of the stomach. The secretion of acid in the urine can be decreased with histamine-2 receptor antagonist or anticholinergic medication.

Adolescent↗
PubMed1995

Newborn penile glans amputation during circumcision and successful reattachment.

Circumcision, the most common operation in male patients in the United States, is performed by a variety of health care professionals. Although not technically difficult, it results in a large number of reported and unreported complications annually. We report the successful reattachment of a distal penile glans, which was amputated when the Sheldon clamp was used for newborn circumcision. The literature is reviewed, and prevention and treatment of this type of circumcision injury are described.

Amputation, Traumatic↗
PubMed1995

Postoperative adhesion formation after urological laparoscopy in the pediatric population.

The risk of intraperitoneal adhesion formation is a concern with transperitoneal laparoscopic surgery. To evaluate the incidence of adhesions after interventional urological laparoscopy, we reviewed 41 pediatric patients who had undergone second-look procedures. The number of adhesions and quantitation of the degree of each adhesion were assessed. Major laparoscopic procedures were performed previously in 8 patients, moderate in 29 and minor in 4. Adhesions were noted in 4 patients (9.8%), including 2 adhesions at the operative site and 2 at trocar sites. The risk of adhesions increased with the extent of dissection. Two adhesions developed after major procedures but the grade and extent of these adhesions were minimal. In the majority of patients re-peritonealization occurred with minimal or no scarring noted. Although adhesions may occur with pediatric urological laparoscopic procedures, the incidence appears lower than what one would expect with open exploration.

Child↗