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Biomedical subjects

G Steinhardt

Publications and source records attributed to G Steinhardt.

At least 19 recordsLinked to original sources
PubMed1996

Bladder stimulation therapy improves bladder compliance: results from a multi-institutional trial.

PURPOSE: We examined data from multiple institutions to determine whether intravesical bladder stimulation therapy is effective in improving bladder compliance by increasing bladder capacity and lowering bladder storage pressures. MATERIALS AND METHODS: The charts of 568 patients from 11 institutions were evaluated. Of the 568 patients 335 had adequate and accurate pretreatment and posttreatment urodynamic studies, and were included in this study. A total of 155 patients was from Children's Memorial Hospital, while the remaining 180 were from 10 other institutions. Bladder capacity and bladder capacity pressure were determined for each patient before and after therapy. RESULTS: Overall, 53% of patients had increased bladder capacity of 20% or greater after treatment (average increase 105 cc), which represents a 63% increase from pretreatment values. This increase occurred in an average of 1.9 years. Further analysis of this subset of patients revealed that in 90% intravesical storage pressures were decreased or maintained within a safe range (less than 40 cm. water). Evaluation of patients who did not respond to bladder stimulation with a 20% or greater increase in bladder capacity revealed that they had nearly normal bladder capacity before therapy. When the data on bladder capacity and bladder capacity pressure from Children's Memorial Hospital were compared to results from the 10 other institutions, there were no appreciable differences. CONCLUSIONS: Bladder stimulation is effective in increasing bladder capacity without significantly elevating storage pressure in a majority of patients. We conclude that this technique is safe and effective in improving bladder compliance, and that it is reproducible elsewhere.

Adolescent↗
PubMed1995

Ethylene oxide allergy in children with spina bifida.

BACKGROUND: Allergic reactions to ethylene oxide (EtO-treated products have occurred in several children with myelomeningoceles. OBJECTIVE: The object of this study was to define the prevalence and significance of EtO-specific IgE among the children in our myelomeningocele clinic. METHODS: The study population comprised three groups: children clinic. METHODS: The study population comprised three groups: children with myelomeningoceles, chronically ill controls (defined as children who had undergone at least three major operations), and well-child controls. Serum specimens were collected from each child, and a commercially available ELISA designed to identify IgE directed against both EtO and latex was performed on the specimens. RESULTS: Seventeen of 75 (23%) children with myelomeningoceles had antibodies directed against EtO, as did 1 of 26 (4%) chronically ill controls. None of the 25 well controls had detectable levels of anti-EtO IgE. Children with antibodies directed against EtO were more likely to be atopic (p = 0.007) and to have a shunt (p = 0.021) and were markedly more likely to have antibodies directed against latex (p = 0.001). On average they had undergone more shunt revisions and other operations than had children without anti-EtO antibodies. CONCLUSION: During the period of study no child had anaphylaxis thought to have been due to EtO exposure.

Adolescent↗
PubMed1995

Latex allergy in children with spina bifida.

We studied the prevalence of latex-specific IgE among the children in our myelomeningocele clinic and several groups of controls using skin tests, a commercially available ELISA and an in-house RAST. Thirty-nine of 83 (47%) children with myelomeningocele had antibodies directed against latex as did 6 of 40 (15.7%) chronically ill controls, 4 of 105 (3.8%) medical controls and 2 of 75 (2.7%) well controls. Within each study group the likelihood of a positive skin test increased with the number of operations the subject had undergone. Children with myelomeningocele were much more likely to have antibodies to latex than were chronically ill controls with similar surgical histories. A retrospective chart review of 18 years and a total of 646 operations disclosed only one episode of intraoperative anaphylaxis which appeared to be related to latex within our study group.

Adolescent↗
PubMed1994

Effects of experimental ureteral obstruction on platelet-derived growth factor-A and type I procollagen expression in fetal metanephric kidneys.

Complete ureteral obstruction in fetal opossum kidneys has been used as an experimental method to induce tubulointerstitial damage and interstitial fibrosis. However, the molecular events underlying extracellular matrix deposition are currently unknown. Cytokines such as platelet-derived growth factor (PDGF) are considered possible participants in these processes. In this study we used a marsupial model of ureteral obstruction to examine the expression of PDGF-A and type I procollagen mRNAs by in situ hybridization. Complete unilateral ureteral obstruction was performed in six animals at midtrimester human equivalent. Obstructed kidneys, as well as the contralateral and age-matched sham kidneys, were harvested at 1, 3, 5, 10, and 20 days post obstruction. Morphological assessment of the obstructed kidneys harvested between 1 and 5 days post obstruction showed mild tubulocystic changes, interstitial fibrosis, and inflammation compared with controls. Kidneys harvested at days 10 and 20 showed moderate tubulointerstitial damage compared with kidneys harvested after 1 and 5 days. PDGF-A mRNA signal of low abundance was detected within renal interstitial cells, urothelial cells of the pelvis, and focally within epithelial cells of immature distal convoluted tubules in non-obstructed kidneys. Type I procollagen mRNA expression was spatially co-distributed with PDGF-A-expressing interstitial cells. PDGF-A and type I procollagen signal intensities in obstructed kidneys harvested 10 and 20 days post obstruction were increased several fold compared with controls and kidneys harvested 1-5 days post obstruction. Both PDGF-A and type I procollagen mRNA increases correlated with morphological features of tubulointerstitial damage. Our results suggest that PDGF-A may participate in this form of fetal kidney damage.

Animals↗
PubMed1994

Immunocytochemical localization of vacuolar H-ATPase in the opossum (Monodelphis domestica) kidney: comparison with the rat.

With two different antibodies (a monoclonal antibody to the C terminus of the 31-kd subunit of H-ATPase and a polyclonal rabbit antiserum to whole bovine H-ATPase) the vacuolar-type H-ATPase pump in the different nephron segments of the gray short-tailed (Monodelphis domestica) opossum kidney has been immunocytochemically localized. There was moderate staining of the brush border and subvillar invaginations in the proximal convoluted tubules (PCT) of the opossum kidney only with the rabbit antiserum and not with the monoclonal antibody. This was in contrast to the rat kidney, where both antibodies showed significant staining of the brush border and subvillar invaginations. There was very minimal staining in the apical region of the thick ascending limb cells of the opossum as compared with a mild degree present in the rat kidney. The pattern and intensity of staining were similar in the remaining distal nephron segments with the only difference being that type A intercalated cells in the outer and inner medullary collecting ducts were less polarized in the opossum kidney. These findings suggest that different isoforms of H-ATPase exist in the brush border of the PCT versus the intercalated cells of the collecting duct in the opossum and between the PCT of opossum and rat kidneys.

Animals↗
PubMed1992

The risk of abdominal operations in children with ventriculoperitoneal shunts.

Ventriculoperitoneal (VP) shunts are the operations of choice for patients with hydrocephalus in most pediatric hospitals. Children with VP shunts frequently undergo abdominal operations unrelated to their shunts, which might lead to shunt infections or to malfunctions related to adhesions. Although prophylactic antibiotics are usually used in this setting, there are few data to support their use, or to assess other risks to the shunt from the abdominal procedures. Consequently, we reviewed the records of 37 children with VP shunts who underwent a total of 44 abdominal operations. In 8 cases, the genitourinary (GU) tract was opened (ureteral reimplantation, bladder augmentation, nephrectomy), whereas in 18 patients the gastrointestinal (GI) tract was opened (appendectomy, gastrostomy, small/large bowel resection). In 18 operations neither GI nor GU tract was opened (lysis of adhesions, herniorrhaphy, orchiopexy). Antibiotic coverage was highly variable: 9 received no antibiotics, 9 received antibiotics only postoperatively, 4 were given antibiotics only preoperatively, and in 22 cases antibiotics were given both preoperatively and postoperatively. One shunt that was involved in a periappendiceal abscess was exteriorized and later successfully replaced. In the remaining cases, no episodes of shunt infection or malfunction occurred in 1 to 10 years of follow-up. Likewise, no abdominal cerebrospinal fluid pseudocysts formed as a result of abdominal adhesions. These data demonstrate that children with VP shunts can safely undergo abdominal operations, even when the GI or GU systems are opened, with minimal risk of shunt infection or malfunction. Rigid protocols of prophylactic antibiotics cannot be supported by this series.

Abdomen↗
PubMed1992

Fetal nephrotoxicity.

Investigation of fetal nephrotoxicity by maternally administered nephrotoxins is hampered by many constraints, including the maternal effects of the nephrotoxin, the ability of the nephrotoxin to cross the placenta and the difficulties associated with direct fetal intervention. In the pouch young of the North American opossum, Didelphis virginiana, we describe the toxic effects of a heavy metal on the immature metanephric kidneys. Varying doses of uranyl nitrate, a heavy metal salt, were administered to opossum pups in the pouch approximately 20 days after birth and the kidneys were harvested 3 to 12 days later for histological analysis. Group 1 consisted of 4 untreated and 5 saline treated pups. Group 2 (9 pups) received 10 to 15 mg./kg. intraperitoneal uranyl nitrate. Group 3 (6 pups) were given a uranyl nitrate dose of 25 mg./kg. Group 4, the high dose group, received either 58 mg./kg. (3 pups) or 87 mg./kg. (3 pups) of intraperitoneal uranyl nitrate. Group 1 kidneys demonstrated no pathological changes except for some mild renal tubular vacuolization seen in the saline treated animals. In group 2 tubular dilatation and necrosis were present 3 days after treatment; tubular regeneration could be seen by day 7. In group 3 glomerular cystic changes, interstitial fibrosis and tubular regeneration were present by day 7. Some restoration of normal architecture occurred by day 12 with fibrosis apparent. Group 4 animals demonstrated much more pronounced cystic changes of glomeruli and tubules as early as day 5 with marked interstitial fibrosis and prominent tubular regeneration. By day 12 group 4 pups continued to demonstrate significant and severe glomerular and tubular cystic changes with marked interstitial fibrosis. Inflammation, although present in all groups (except control), was never prominent. This first description of the effect of heavy metal toxicity on the immature metanephric kidney could provide an insight into the mechanisms of disordered kidney growth.

Animals↗
PubMed1992

Ventriculo-ureteral shunt without nephrectomy.

Some patients with hydrocephalus cannot be adequately treated with either ventriculo-peritoneal or ventriculo-atrial shunts. Ventriculo-ureteral (VU) shunts are seldom considered in this group of patients because of the belief that nephrectomy is an essential part of the procedure. We report a case in which a VU shunt was performed with direct ureteral re-implantation and we suggest that a VU shunt is a reasonable alternative for the treatment of a patient with difficult-to-manage hydrocephalus.

Cerebrospinal Fluid Shunts↗
PubMed1991

Genitourinary tract malformations and maternal cocaine abuse.

We report on 4 cases of congenital urologic anomalies in association with maternal cocaine abuse and review all 23 cases documented in the literature. Male infants predominate and have either isolated genital abnormalities, hydronephrotic conditions, or classic prune-belly syndrome. Female infants present with hydronephrosis or cloacal abnormalities along with masculinization of the external genitalia. Cocaine disrupts morphogenesis by causing intense vasoconstriction of the uterine and fetal circulation. Interruption of calcium metabolism may also be responsible for the hydronephrosis observed.

Abnormalities, Drug-Induced↗
PubMed1990

Mucosal proliferation characteristics in ureterosigmoidostomy: effect of calcium supplement.

Ureterosigmoidostomy, frequently performed in children for urinary diversion, is a known premalignant condition. Dietary calcium supplements have been shown to normalize mucosal proliferative patterns in other human premalignant colonic conditions, which might decrease the risk of cancer. However, calcium supplementation has not been investigated in ureterosigmoidostomy. We used a rat model to study the effects of increased dietary calcium on the progression to carcinoma in ureterosigmoidostomy. Twenty-five Wister rats underwent ureterosigmoidostomy by anastomosis of bladder trigone and ureters to sigmoid, and were divided into two groups: group 1, regular diet (14); and group 2, calcium supplemented (2%) diet (11). All animals received the diet for 9 months. At death the anastomosis was weighed and examined histologically. In addition, ornithine decarboxylase (ODC), an enzyme involved in polyamine synthesis that becomes elevated in neoplastic and proliferative disorders, was determined at the anastomosis and 8 cm proximal (normal colon). All animals developed proliferative metaplastic polyposis at the anastomosis. Tumor weights were 2.6 +/- 1.1 g for group 1 and 4.8 +/- 1.2 g for group 2 (P less than .05). The ODC levels were: group 1, normal colon 78.2 +/- 15.6 and tumor 321.3 +/- 58.8 (P less than .002); and group 2, normal colon 425.8 +/- 65.4 and tumor 568.0 +/- 40.9 (P = NS). The difference between group 1 normal colon and group 2 normal colon was significant (P less than .001), as was group 1 tumor and group 2 tumor (P less than .02).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Experimental ureteral obstruction in the fetal opossum. I. Renal functional assessment.

The North American opossum Didelphis virginiana was used as a model for fetal urinary obstruction. In this animal the fetus develops on a teat in a pouch and, therefore, it is accessible to surgical intervention. Unilateral ureteral obstruction was created at a mid trimester developmental equivalent in 8 pups, late ureteral obstruction was created in a similar fashion in 6 pups at a full-term equivalent and unobstruction of 9 pups was accomplished with a ureteroneocystostomy at a full-term equivalent. After early intervention 6 pups were found to have only partial ureteral obstruction as measured by mild dilatation and probe patency of the ureter. The control group consisted of 11 unoperated animals. The animals were maintained until adulthood when they were harvested after obtaining creatinine clearances from both kidneys. All dilated urinary systems were cultured for bacteria and they were sterile.

Animals↗
PubMed1990

Long-term survival in an infant with urethral atresia.

Complete urethral atresia is an anomaly that previously was incompatible with life. We report on a surviving infant with this anomaly. As a fetus urinary decompression was accomplished with a vesicoamniotic shunt. Peritoneal dialysis was initiated shortly after birth and at 9 months supramembranous scrotal inlay urethroplasty was performed to provide for egress of urine from the bladder. A maternal renal allograft was performed when he was 12 months old. When the patient was 3 1/2 years old he had normal renal function and emptied the bladder to completion through the reconstructed urethra. Although mildly delayed, he continues to progress with all developmental milestones.

Cystostomy↗
PubMed1987

Phthalate esters and semen quality parameters.

Analysis of reports in the world's literature suggests that average sperm densities for groups of unselected males were relatively constant at about 108 million cells per ml prior to 1950. Subsequent to that time mean sperm densities appear to have declined. Regression analysis indicates the existence of significant negative correlations between mean sperm densities and production of synthetic organic chemicals among other parameters. Phthalate esters are one class of large volume organic chemicals that are known to disturb testicular function in laboratory animals. These compounds are also the most abundant man-made chemicals in the environment. Plots of the concentration of dibutylphthalate in the cellular fraction of ejaculates against either the sperm density or the total number of sperm for the same ejaculates gave two clusters of points. These clusters suggest the existence of two or more populations vis à vis phthalate metabolism; both of which show a negative correlation between phthalate concentration and sperm production.

Dibutyl Phthalate↗
PubMed1987

Urethral hemangioma.

Urethral hemangiomas are uncommon lesions that can cause significant hemorrhagic morbidity. Since the lesions tend to recur complete urethral excision and subsequent urethral reconstruction have been advocated in the past as the preferred method of treatment. We present an alternative method of management of urethral hemangioma.

Adolescent↗
PubMed1984

Penile necrosis in patients with diabetes mellitus and end stage renal disease.

We report on 2 patients who had spontaneous necrosis of the penis associated with end stage renal disease and diabetes mellitus. On postmortem examination extensive vascular changes were present in each penis. Treatment of penile necrosis is necessitated by the inability of the patient to void. However, poor wound healing should be expected. The development of penile necrosis in our patients was associated with a poor clinical outcome and death occurred within months of the onset of the lesion.

Adult↗