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Biomedical subjects

J Mandell

Publications and source records attributed to J Mandell.

At least 19 recordsLinked to original sources
PubMed1999

Upper ureteral reconstructive surgery.

Upper ureteral reconstructive surgery encompasses a wide variety of procedures directed at the correction of abnormal processes and structural defects in the proximal ureter. Although some of these techniques have strict indications for specific causes, technical innovations have led to development of numerous alternatives in upper ureteral reconstructive surgery. These innovations provide the practicing urologist with various options from which to choose for the management of upper ureteral disease.

Adult↗
PubMed1998

Unilateral suprainguinal ectopic scrotum: the role of the gubernaculum in the formation of an ectopic scrotum.

A rare case of ectopic scrotum is described together with a review of the literature and a discussion of the embryological role of the gubernaculum in the formation and location of normal and ectopic scrota. We identified 16 reported cases of a suprainguinal ectopic scrotum, 4 cases of a femoral ectopic scrotum, 26 cases of penoscrotal transposition, and 19 cases of a perineal (accessory) scrotum. Although the gubernaculum is a prerequisite for the ultimate location of both the testis and scrotum, its role is complicated by the subsequent differential growth of the labioscrotal folds in which the gubernaculum is stabilized. If this interaction is disturbed, the result may be a suprainguinal ectopia, penoscrotal transposition or a perineal scrotum. A femoral ectopic scrotum, unlike the above, is the result of an aberrant gubernacular stabilization. While the etiology of these malformations is likely to be multifactorial, the existence of an inbred strain of rats characterized by a high incidence of an ectopic scrotum suggests a genetic component to this anomaly.

Animals↗
PubMed1998

Prenatal diagnosis. Therapeutic implications.

Prenatal diagnosis of structural anomalies provides the opportunity to influence the postnatal outcome. The greatest value of antenatal screening is, in fact, the awareness of the urogenital abnormalities, such as presumed UPJ obstruction, so that appropriate investigation and treatment can be offered immediately after birth and before permanent damage occurs owing to obstruction or infection. Crombleholme and coworkers reported that prenatal consultation impacted favorably on outcomes by preventing early termination of pregnancy owing to misconceptions about the existing condition. It also permitted delivery of complex cases in a tertiary care setting, thereby preventing a delay in postnatal management. A systematic approach to the infant in the prenatal and postnatal periods is important. The natural history of prenatally detected hydronephrosis continues to be defined, and there is no ideal test to predict the outcome of UPJ obstruction. Several investigators are evaluating various markers in urine that may help to identify fetuses who require early postnatal intervention. More complete understanding regarding the natural history of unilateral pediatric UPJ obstruction and its response to surgery will not be available until several randomized, prospective clinical studies are completed. The collaborative effort of obstetricians, neonatologists, geneticists, radiologists, and pediatric urologists should provide answers to many questions surrounding prenatally diagnosed UPJ obstruction.

Algorithms↗
PubMed1998

Initial studies of holmium:YAG laser creation of spinal defects in fetal rabbits: model for urologic effects of myelomeningocele.

Myelomeningocele (MMC) is characterized by paraplegia and incontinence, often necessitating surgery. Current models of MMC in sheep and primates create a spinal defect long after anomalous neural tube closure ordinarily occurs. An ideal model of MMC would allow creation of the defect at the earliest age in a low-cost species with a short gestation. We present a method utilizing the holmium laser to create spinal defects in rabbits in utero for the study of the pathophysiology and repair of MMC. Pregnant rabbits of 22 to 23 days' gestational age were prepared and draped in sterile fashion for laparotomy under general anesthesia. The abdomen was opened, and both uterine horns were inspected. Double opposing pursestring sutures were placed to secure the chorioamniotic membranes over the fetal lumbar spine. Amniotic fluid was removed with a needle and saved. Electrocautery was used to open the uterus within the pursestring suture, exposing the fetal dorsum. The spine was exposed by laser dissection of the fetal dorsal musculature. Posterior laminectomy was accomplished with laser incisions of each side of the spinous process, leaving the underlying dura and cord exposed. The pursestring was then cinched, amniotic fluid was returned, and the uterus and trocar sites were closed. Cesarian section was performed at 30 to 31 gestational days, and the pups were examined and then humanely sacrificed for histologic evaluation of the lesion. The rabbit is an inexpensive species with a short gestation (33-35 days), and four or more fetuses may be operated on per litter, with the remainder serving as controls. Utilization of minimally invasive techniques including holmium:YAG laser dissection facilitates creation of spinal defects at an early age in this small-animal model.

Animals↗
PubMed1997

The incidence of renal anomalies at full term in fetal rats is synergistically increased by estradiol (but not testosterone) supplementation on day 18 of alcoholic gestation.

BACKGROUND/PURPOSE: Fetal alcohol syndrome is characterized by facial dysmorphology, mental and growth retardation, and somatic anomalies including hydronephrosis. The authors sought to determine the influence of exogenous testosterone or estradiol on the incidence of hydronephrosis in a rodent model of fetal alcohol syndrome (FAS). METHODS: Pregnant rats were fed a liquid diet containing 35% ethanol-derived calories from gestation day 6 through 15, with exogenous testosterone or estradiol supplementation on day 18. On day 20, fetal kidneys were examined for evidence of hydronephrosis, and fetal serum estradiol concentrations were determined by radioimmunoassay. RESULTS: Maternal estrogen supplementation resulted in very high fetal serum estradiol levels that were not additionally increased by alcoholism. Despite this fact, the expression of renal malformations was highest in the alcoholic, estradiol-supplemented offspring. Additionally, the rate of renal malformations was significantly higher in the estrogen-supplemented alcoholic group than in the strictly estradiol animals, yet the fetal serum estradiol concentrations did not differ between the two groups. CONCLUSIONS: This suggests that ethanol may act synergistically with estradiol to increase the rate of renal anomalies including hydronephrosis. Such damage may persist via a suppression of normal testosterone-stimulated renal growth and development. FAS includes significant renal anomalies characterized by hydronephrosis in both animal models and affected children. Although the long-term functional sequelae of hydronephrosis and reflux are well known, the progression of renal disease in FAS children remains to be documented.

Animals↗
PubMed1997

Continent urinary diversion: the Children's Hospital experience.

PURPOSE: Continent urinary diversion has become increasingly important for treating childhood urinary tract pathology that cannot be managed by direct reconstructive techniques. We review our 9-year experience with continent diversion. MATERIALS AND METHODS: Since 1986 continent diversions were created in 74 patients 3 to 38 years old (mean age 13.7). The underlying pathological condition was the exstrophy/epispadias complex in 34 patients, neurological disorders in 23, malignancy in 13 and other congenital anomalies in 4. Followup averaged 5.2 years after the last procedure. Nonbladder reservoirs in 39 patients (53%) were fashioned from ileocolic (17), colic (7), gastrocolic (6), sigmoid (3), gastrosigmoid (2), ileosigmoid (2), ileal (1) and gastroileac (1) segments. When possible, the native bladder was incorporated into the reconstructive strategy. A total of 26 patients underwent bladder augmentation with intestine or stomach, including ileal (11), gastric (8), sigmoid (3), gastroileac (2) and ileocolic (2) segments. Nine other patients did not require bladder augmentation. Continence mechanisms were a flap valve (Mitrofanoff principle) in 50 patients, nipple valve in 15 and ileal plication (Indiana pouch) in 9. When the Mitrofanoff principle was used with a native bladder reservoir in 30 cases, outlet resistance was altered by bladder neck division (15), fascial sling placement (6) or Young-Dees-Leadbetter bladder neck reconstruction (2). In the remaining 7 patients the bladder neck remained intact. RESULTS: Excellent continence was obtained. The Mitrofanoff principle initially provided continence in 41 patients (82%). Six of the 9 incontinent patients were dry after a single revision. A total of 13 patients (87%) with nipple valves and 7 (78%) with Indiana pouches were dry, and the remaining 5 were cured after a single revision. Ultimately continence was achieved in 71 of the 74 patients (96%) after a maximum of 2 operations. Of the 48 complications in 29 patients the most common were difficulty in catheterizing (11), stones (11), infection (8) and upper tract deterioration (4). CONCLUSIONS: Many options exist for reconstructing complex anomalies. Choices must be individualized based on patient anatomy. The dry state may be achieved in most cases without resorting to a bag on the abdomen.

Adolescent↗
PubMed1997

Amnioscopic endofetal illumination with infrared-guided fiber.

Minimally invasive amnioscopic surgery has several potential advantages over traditional open hysterotomy, including the reduction of the risk of preterm labor and spontaneous abortion. Adequate visibility of the fetal target organ is obligate to the success of in utero procedures. This is a preliminary report on the use of an end-emitting infrared fiber (750 microns; 810-nm wavelength) that allows image fusion with Infravision videocamera systems (Gabriel Medical, Lafayette, LA). Once placed, this fiber can serve as a homing beacon to identify the fetal bladder in the surgical creation of an amnioscopic vesicostomy for the relief of obstructive uropathies. Under general endotracheal halothane anesthesia, amnioscopic access was established in time-dated pregnant ewes using one 3.7-mm and two radially dilating 2-mm to 5-mm trocars. This access allowed the investigation of several methods of intravesicular infrared fiber placement. Ultrasound-guided direct needle puncture is the quickest method of accessing the fetal bladder but is unreliable when the bladder is empty. Accurate placement of the access needle directly over the suprapubic region was accomplished with amnioscopic assistance. The fiber was also placed transurethrally in one female and one male fetus, with subsequent perforation of the female's bladder. Successful infrared bladder illumination was accomplished in all animals. The fusion integration of this camera system allows simultaneous viewing by visible spectrum and near-infrared wavelengths. We believe that this system provides a further degree of safety for amnioscopic procedures.

Animals↗
PubMed1997

Assessment of access strategies for fetoscopic urologic surgery: preliminary results.

Attempted endoscopic fetal interventions have been increasingly reported, given the knowledge that minimizing the trauma to the uterus by a small access portal can allow prolonged amnioscopic-guided surgery. Numerous fetal anomalies have been targeted for these interventions, including congential obstructive uropathies. This preliminary investigation explored innovative access strategies utilizing time-dated pregnant ewes, 95 to 100 days' gestation (term 145 days). Two strategies were specifically investigated: percutaneous, ultrasonographically guided microamnisocopy and ultrasonographically aided, laparoscopically guided amnioscopy. Both strategies provided excellent fetal visibility and were facilitated by the use of small trocars and microlaparoscopic instrumentation, which promoted prolonged amnioscopy with minimal access trauma.

Amnion↗
PubMed1997

Subcellular distribution of SERCA and calcium-activated ATPase in rabbit and human urinary bladder smooth muscle.

Previous studies have demonstrated that calcium storage and release from IP-3-dependent sites in the sarcoplasmic reticulum play an important role in the contractile response of the rabbit urinary bladder to both field stimulation (mediated via neurotransmitter release) and bethanechol (direct muscarinic stimulation). In view of the importance of SERCA in urinary bladder smooth muscle function, we studied the distribution of SERCA by two methods: using Western blotting to quantitate the protein concentration and by enzyme analysis using thapsigargin to specifically inhibit SERCA. Rabbit and human samples of urinary bladder smooth muscle were homogenized and the homogenate separated into three particulate fractions by differential centrifugation: nuclear-cell wall, mitochondrial, and microsomal. The protein concentration of these three particulate fractions was determined and the SERCA protein level quantitated by Western blotting using SERCA-2 antibodies. The calcium-ATPase activity was quantitated using standard enzymatic analysis and the thapsigargin sensitivity determined. The results demonstrated that: (1) the concentration of SERCA was significantly greater in the microsomal fraction than in either of the other fractions for both rabbit and human bladder smooth muscle; (2) the enzymatic activities of both total calcium-activated ATPase and thapsigargin-sensitive calcium ATPase were evenly divided among the three fractions, and (3) the enzymatic activity of both total calcium-activated ATPase and thapsigargin-sensitive calcium ATPase of the rabbit exceeded that of the human. In conclusion, the distribution of SERCA and calcium-ATPase of the rabbit bladder smooth muscle was similar to that in the human bladder smooth muscle, although activities in rabbit were significantly greater than those of human tissue.

Animals↗
PubMed1997

Subcellular distribution of SERCA and calcium-activated ATPase in rabbit and human urinary bladder smooth muscle.

Previous studies have demonstrated that calcium storage and release from IP3-dependent sites in the sarcoplasmic reticulum play an important role in the contractile response of the rabbit urinary bladder to both field stimulation (mediated via neurotransmitter release) and bethanechol (direct muscarinic stimulation). In view of the importance of SERCA (see text) in urinary bladder smooth muscle function, we studied the distribution of SERCA by two methods; using Western blotting to quantitate the protein concentration and by enzyme analysis using thapsigargin to specifically inhibit SERCA. Rabbit and human samples of urinary bladder smooth muscle were homogenized and the homogenate separate into three particulate fractions by different centrifugation: the cell wall-nuclear, mitochondrial, and microsomal. The protein concentration of these three particulate fractions was determined and the SERCA protein level quantitated by Western blotting using SERCA-2 antibodies. The calcium ATPase activity was quantitated using standard enzymatic analysis and the thapsigargin sensitivity determined. The results demonstrated that (1) the concentration of SERCA was significantly greater in the microsomal fraction than in either of the other fractions for both rabbit and human bladder smooth muscle; (2) the enzymatic activities of both total calcium-activated ATPase and thapsigargin-sensitive calcium ATPase were evenly divided among the three fractions, and (3) the enzymatic activity of both total calcium-activated ATPase and thapsigargin-sensitive calcium ATPase of the rabbit exceeded that of the human. In conclusion, the distribution of SERCA and calcium ATPase of the rabbit bladder smooth muscle was similar to that in the human bladder smooth muscle, although activities in rabbit were significantly greater than those of human tissue.

Adenosine Triphosphatases↗
PubMed1997

XX sex reversal: molecular analysis of the SRY/ZFY regions.

PURPOSE: The mammalian sex determining gene, sex region Y chromosome (SRY), is now firmly established as the testis determining locus. The SRY locus is close to the short arm Y terminus and just distal to zinc finger Y region (ZFY), a locus previously thought to be involved in testicular differentiation and the male phenotype. We report on XX sex reversal, a rare sex chromosomal disorder in humans. MATERIALS AND METHODS: Routine amniocentesis revealed an XX fetal karyotype, although at birth the neonate was phenotypically male. Radiographic evaluation showed a normal male urethra and the absence of any female internal genitalia. Subsequent molecular analysis with polymerase chain reaction amplified sequences of the SRY and ZFY loci were positive. RESULTS: This case is the fourth in our series of XX sex reversed male individuals and to our knowledge the first to be diagnosed perinatally. In all cases the SRY and ZFY loci are present, presumably on the paternal X chromosome, as well as a Klinefelter phenotype. These sex reversing translocations are thought to be due to an unequal meiotic recombination of the distal X and Y short arms during male gametogenesis. The tendency for XY translocations to break between the SRY and ZFY loci was not seen in these apparent microtranslocation cases. CONCLUSIONS: These 4 cases demonstrate the usefulness of molecular followup of clinically perplexing sexual discordance. We conclude that SRY and ZFY polymerase chain reaction amplification studies should be performed when sexual discrepancies are noted on prenatal ultrasound and karyotype analysis.

Chromosome Aberrations↗
PubMed1996

Renal cortical neoplasm in a child with dialysis-acquired cystic kidney disease.

Acquired cystic disease of the kidney is a common phenomenon in long-term adult dialysis patients with endstage renal disease. Malignant degeneration with cortical neoplasms is also well documented in this patient population. Although the prevalence of this disease process is common in adults, the literature is sparse concerning its occurrence in children. To our knowledge, we report the youngest case of renal cortical neoplasm associated with dialysis-acquired renal cystic disease in a 13-year-old boy.

Adolescent↗
PubMed1996

Use of neodymium: yttrium-aluminum-garnet laser for removal of a congenital posterior urethral polyp in a 3-year-old child: a case report and review of the literature.

Congenital posterior urethral polyps are an uncommon but well-described disease process known to cause hematuria or bladder outlet obstruction in boys. Conventional treatment has included transurethral resection or open cystotomy for complete removal of the polyp. We report the first use of the neodymium:yttrium-aluminum-garnet laser for endoscopic excision of a posterior urethral polyp in a 3-year-old boy.

Child, Preschool↗
PubMed1996

Reconstructive options in genitourinary rhabdomyosarcoma.

PURPOSE: We attempted to develop a rational and consistent scheme for surgical reconstruction in patients with genitourinary rhabdomyosarcoma. MATERIALS AND METHODS: We reviewed the records of 35 patients with resectable genitourinary rhabdomyosarcoma treated from 1970 to 1993. RESULTS: Primary sites included bladder in 11 cases, prostate in 13, vagina/uterus in 9 and pelvic tumors of uncertain origin in 2. A total of 33 patients underwent surgery, including partial and radical cystectomy in 17 (bowel conduit diversion in 10, continent urinary diversion in 6 and ureterosigmoidostomy in 1). Overall 30 of the 33 surgical patients are free of disease 4 months to 24 years after diagnosis. CONCLUSIONS: A nonrefluxing colon conduit is appropriate at cystectomy. Continent diversion fashioned from the original conduit may be planned as the patient achieves a durable disease-free status.

Adolescent↗
PubMed1995

Fetal suprarenal masses: sonographic appearance and differential diagnosis.

We present eight cases of suprarenal masses detected sonographically in fetuses of 20-41 weeks. The appearances of the masses included hyperechoic (n = 2, both pulmonary sequestrations), solid isoechoic (n = 1, a neuroblastoma), purely cystic (n = 3, two neuroblastomas, one enteric cyst) and mixed or complex (n = 2, one neuroblastoma and one renal cyst). Three of the fetuses with neuroblastoma had normal scans in the second trimester, and in all four the neuroblastomas were detected after 36 weeks. This study demonstrates the differential diagnosis of suprarenal masses in fetuses. Neuroblastomas can have a solid, purely cystic or complex sonographic appearance. Although not all suprarenal masses are neuroblastomas, the newborn with a prenatally detected suprarenal mass should be evaluated for the possibility of a neuroblastoma, since early diagnosis of this malignancy can be curative.

Adrenal Gland Neoplasms↗
PubMed1995

Prenatally diagnosed bilateral hyperechoic kidneys with normal amniotic fluid: postnatal outcome.

We evaluated a subset of infants with bilateral markedly hyperechoic "bright" kidneys noted prenatally in association with normal amniotic fluid volume during gestation. Prenatal ultrasound showed increased renal parenchymal echogenicity bilaterally with preservation of the medullary pyramid architecture. These children were followed for up to 3 years to determine potential changes in the sonographic appearance of the echogenic renal parenchyma and to assess renal function. In 3 years 8 cases of bilateral hyperechoic fetal kidneys were identified. During postnatal followup renal echogenicity resolved in 4 cases, diminished in 1 and remained the same in 3. The serum creatinine and electrolytes were normal in all cases followed for more than 3 months. Other renal findings included vesicoureteral reflux in 2 of 7 cases, mild pelvic ectasia in 1 and tiny medullary calcifications in 1. The specific etiology of increased echogenicity is unknown, although 1 infant appeared to have a form of autosomal recessive disease with liver hyperechogenicity as well. We conclude that fetuses with bilateral hyperechoic kidneys associated with normal amniotic fluid volume have a favorable outcome. Ultrasonographic finding of marked parenchymal hyperechogenicity appears to improve with time; in our experience renal function is normal and the infants thrive. Continued followup is necessary to determine the long-term natural history of this phenomenon, as is subsequent prenatal and postnatal evaluation of future siblings to assess genetic risk.

Amniotic Fluid↗