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Biomedical subjects

R I Silver

Publications and source records attributed to R I Silver.

28 records · Page 2Linked to original sources
PubMed1997

Urolithiasis in the exstrophy-epispadias complex.

PURPOSE: We sought to determine the incidence of urolithiasis in patients with the exstrophy-epispadias complex, associated risk factors and guidelines for the proper clinical management of this problem. MATERIALS AND METHODS: We retrospectively reviewed the chart and x-rays of 530 patients with the exstrophy-epispadias complex treated at our institution. RESULTS: Stones formed in 77 of the 530 patients (15%), including 16% of those with classic exstrophy, 25% of those with cloacal exstrophy and 3% of those with epispadias. White and male individuals were most commonly affected. Most calculi formed in the bladder, whether native or augmented by enterocystoplasty. Standard techniques were successful for stone removal. Most calculi consisted of calcium apatite, calcium oxalate monohydrate or magnesium ammonium phosphate, usually in combination with at least 1 other element. The risk of stone formation was associated with augmentation cystoplasty (p < 0.001) and a bladder neck procedure to increase outlet resistance (p < 0.001). Other risk factors included urinary tract infection, foreign bodies, vesicoureteral reflux and urinary stasis but not acidosis or immobilization. Stones recurred in 30 patients (39%), including equal numbers of those treated with open and closed techniques, and recurrence was associated with urinary tract infection or struvite composition (p < 0.05). Serum calcium abnormalities were not present in any patient, including those with metabolic acidosis or prolonged immobilization. Urinary chemistry studies were incomplete or unavailable. CONCLUSIONS: These data suggest that urolithiasis in the exstrophy-epispadias complex is related to risk factors associated with surgical reconstruction of this condition. The role of metabolic abnormalities that may predispose to urolithiasis is unknown but under investigation. Standard treatment is effective but stone recurrence remains a significant problem. Urine chemistry data may provide information to help minimize stone development in this patient population.

Abnormalities, Multiple↗
PubMed1997

Penile length in adulthood after exstrophy reconstruction.

PURPOSE: We attempted to determine whether the penis in adulthood after exstrophy reconstruction is short because of a congenital defect in the size of the corpora cavernosa. MATERIALS AND METHODS: Pelvic magnetic resonance imaging was performed on 10 men who underwent exstrophy reconstruction in childhood, and 10 age and race matched controls. Measurements of penile and pelvic anatomy were compared. RESULTS: The corpora cavernosa in men after exstrophy reconstruction were shorter than normal. Dividing total corporeal length into an anterior and posterior segment revealed that the anterior segment was short but the posterior segment attached to the pubic ramus was normal. However, the diameter of the posterior corporeal segment was greater than in controls. Although diastasis of the symphysis pubis increased the intersymphyseal and intercorporeal distances, the angle between the corpora cavernosa was unchanged, presumably because the corporeal bodies were separated in a parallel fashion. CONCLUSIONS: After exstrophy reconstruction the penis is short in adulthood, at least partially due to a congenital deficiency of corporeal tissue. Since diastasis of the pubic symphysis and chordee decrease penile visibility, approximation of the pubic symphysis and procedures to straighten the penis may improve cosmesis. However, because the corpora cavernosa are short, after exstrophy reconstruction the penis will always be shorter than normal in adulthood.

Anthropometry↗
PubMed1997

Renal ultrasonography in newborns with prenatally detected hydronephrosis: why wait?

PURPOSE: Published reports suggest the need to delay renal ultrasound for at least 1 week after birth to avoid a false-negative study due to oliguria. This recommendation has become standard. Considering the recent shift toward expectant management of prenatal hydronephrosis, there may be no advantage to the increased sensitivity of a delayed study. MATERIALS AND METHODS: Radiology records were reviewed for a 5-year period to identify renal ultrasound studies performed within 48 hours of birth. RESULTS: Of 101 neonates known to have hydronephrosis on prenatal ultrasound who underwent sonography within 48 hours of birth 33 had a normal study (including mild hydronephrosis) and documented followup studies. None of these patients had a significant obstructive renal lesion within the first year of life. One child had an obstructive pattern on diuretic renography at age 18 months after previous studies were unremarkable. Cystography in 26 patients demonstrated vesicoureteral reflux in 4 (14.3%). CONCLUSIONS: These data suggest that 1) there is no contraindication to early neonatal renal ultrasonography and 2) voiding cystourethrography is indicated for all infants with a history of prenatal hydronephrosis.

Female↗
PubMed1996

Percutaneous transhepatic endoscopic electrohydraulic lithotripsy of biliary tract calculi after orthotopic liver transplantation.

The development of biliary tract calculi after orthotopic liver transplantation presents a unique clinical problem. Previously described techniques for removing biliary stones by shock wave lithotripsy, litholytic therapy with oral bile acids, and endoscopic mechanical extraction may be ineffective or contraindicated in liver transplant patients. For this reason, percutaneous transhepatic electrohydraulic lithotripsy (EHL) was performed using an 11 French flexible ureteroscope in two pediatric patients who developed biliary tract calculi following orthotopic liver transplant. There were no complications and postoperative follow-up over 4 years has been uneventful. To our knowledge, these represent the first reported cases of percutaneous transhepatic endoscopic EHL to fragment biliary tract stones in a transplanted liver, which for us has been a safe and effective therapeutic option.

Adolescent↗
PubMed1994

Expression and regulation of steroid 5 alpha-reductase 2 in prostate disease.

The androgen dihydrotestosterone is synthesized by the enzyme steroid 5 alpha-reductase, and it is required for growth and development of the prostate. We used immunohistochemistry to examine the expression of the type 2 isozyme of 5 alpha-reductase in benign prostatic hyperplasia and prostate cancer. The type 2 isozyme is highly expressed within stromal cells in both disease states. No type 2 isozyme is detectable in a lymph node metastasis. Immunoblotting studies show that androgen ablation therapies substantially decrease isozyme expression in the epididymis but have a lesser effect on expression in the prostate. Finasteride therapy (2 weeks to 3 years) did not abolish expression of the prostatic type 2 isozyme nor did this drug treatment induce expression of the type 1 isozyme.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1994

Cell type specific expression of steroid 5 alpha-reductase 2.

Isozymes of steroid 5 alpha-reductase (5 alpha-reductase) have crucial roles in androgen physiology by synthesizing the potent hormone dihydrotestosterone. The expression pattern of the 5 alpha-reductase type 2 isozyme was determined in genital and extragenital tissues by developing an immunohistochemical assay using formalin-fixed tissue and affinity purified polyclonal antibodies that specifically recognize this isozyme. Expression was detected in basal epithelial and stromal cells of the normal prostate but not in luminal epithelial cells. Stromal cells of the seminal vesicle also expressed the type 2 isozyme. In contrast, staining was detected in epithelial cells of the epididymis but not in the surrounding stroma. Myofibroblasts in foreskin samples of normal and hypospadiac individuals expressed antigen and were distributed in bands throughout the prepuce, suggesting a clonal origin. In most cells the type 2 isozyme exhibited a perinuclear subcellular distribution. However, in liver hepatocytes the protein was distributed throughout the intracellular membrane compartment.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1993

Tissue distribution and ontogeny of steroid 5 alpha-reductase isozyme expression.

The synthesis of dihydrotestosterone is catalyzed by steroid 5 alpha-reductase isozymes, designated types 1 and 2. Mutation of type 2 results in male pseudohermaphroditism, in which the external genitalia are phenotypically female at birth. Two striking and unexplained features of this disorder are that external genitalia of affected males undergo virilization during puberty and that these individuals have less temporal hair regression. The tissue-specific and developmental expression patterns of the 5 alpha-reductase isozymes were investigated by immunoblotting. The type 1 isozyme is not detectable in the fetus, is transiently expressed in newborn skin and scalp, and permanently expressed in skin from the time of puberty. There was no qualitative difference in 5 alpha-reductase type 1 expression between adult balding vs. nonbalding scalp. The type 2 isozyme is transiently expressed in skin and scalp of newborns. Type 2 is the predominant isozyme detectable in fetal genital skin, male accessory sex glands, and in the prostate, including benign prostatic hyperplasia and prostate adenocarcinoma tissues. Both isozymes are expressed in the liver, but only after birth. These results are consistent with 5 alpha-reductase type 1 being responsible for virilization in type 2-deficient subjects during puberty, and suggest that the type 2 isozyme may be an initiating factor in development of male pattern baldness.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1991

Response to orchiectomy following Zoladex therapy for metastatic prostate carcinoma.

Serum testosterone and prostate-specific antigen (PSA) levels were measured in 3 patients with Stage D2 prostate cancer before and after discontinuation of the long-acting LHRH agonist, goserelin acetate (Zoladex). The patients had received goserelin acetate for ten, sixteen, and thirty months prior to discontinuing the drug because of progressive metastatic disease. In all 3 patients, PSA and testosterone levels increased after goserelin acetate was discontinued. In 2 patients the testosterone level reached normal levels. A bilateral orchiectomy was performed one hundred sixty, one hundred, and seven days, respectively, after the drug was discontinued. In all 3 cases PSA and testosterone levels were reduced following castration, although PSA levels again began to increase within two weeks of orchiectomy in 2 of the 3 patients. These findings suggest that suppression of testosterone by LHRH agonists is not permanent and if tumor progression occurs, maintaining hormone suppression may still be beneficial.

Aged↗
PubMed1988

Abortion hysterectomy for gynecologic pathology.

Abortion hysterectomy has been discredited as the method of performing simultaneous pregnancy termination and elective sterilization for women with undesired pregnancies who simultaneously wish to end their child-bearing potential. The procedure continues to be advocated, however, for cases in which there is an underlying gynecologic pathologic condition. The morbidity of this procedure has not been directly compared with that for indicated hysterectomy in nonpregnant women. Between January 1976 and January 1987, 50 patients underwent abortion hysterectomy at The University of Chicago. The morbidity and mortality rates of these patients were compared with those of 50 premenopausal nonpregnant women undergoing abdominal hysterectomy for gynecologic pathologic status. There was no statistically significant different between the groups in the duration of surgery, estimated blood loss, or infectious morbidity. No operative site infections or other adverse sequelae were noted at the time of final postoperative examination. These data support the relative safety of abdominal abortion hysterectomy for women with undesired pregnancy in whom hysterectomy is indicated for an underlying gynecologic pathologic condition.

Abortion, Therapeutic↗