Biomedical subjects

D M Fenig

Publications and source records attributed to D M Fenig.

3 recordsLinked to original sources

PubMed2001

Abnormal germ cell development in cryptorchidism.

BACKGROUND: Previous studies suggest that two fundamental, probably androgen-dependent, steps in maturation of germ cells normally occur in the prepubertal testis: the disappearance of gonocytes (the fetal stem cell pool) and the appearance of adult dark spermatogonia (the adult stem cell pool) at 2-3 months of age and the appearance of primary spermatocytes (the onset of meiosis) at 4-5 years. Previous studies of small series of cryptorchid boys suggest that both steps are defective in undescended testes and to a lesser degree in descended testes contralateral to unilaterally undescended testes. The purpose of this study is to confirm the previous findings of defective germ cell maturation in a large series of boys with unilateral undescended testes. PATIENTS: Seven hundred and sixty-seven boys with unilateral cryptorchidism who had orchidopexy and bilateral testicular biopsies between birth and 9 years of age were studied. MATERIALS AND METHODS: Total and differential germ cell counts were performed on semithin histologic sections of the biopsies. The results from the undescended and contralateral descended testes were compared using the Wilcoxon signed-rank test and the Wilcoxon-Whitney-Mann U test. RESULTS: Gonocytes failed to disappear and adult dark spermatogonia failed to appear in undescended testes under 1 year of age indicating a defect in the first step in maturation at 2-3 months resulting in failure to establish an adequate adult stem cell pool. Primary spermatocytes failed to appear in undescended testes and appeared in only 19% of contralateral descended testes at 4-5 years of age indicating a defect in the onset of meiosis. CONCLUSION: Unilaterally undescended testes fail to establish an adequate adult stem cell pool which normally occurs at 2-3 months of age and fail to establish adequate meiosis which normally occurs at 4-5 years of age. Similar but less severe changes are seen in the contralateral descended testes. Defects in the two pubertal steps in germ cell maturation are associated with reduced total germ cell counts.

Biopsy↗

PubMed2001

Intravesical Jackson-Pratt drain for urinary diversion after augmentation cystoplasty.

PURPOSE: Augmentation cystoplasty has become a primary form of bladder management in children with a noncompliant bladder. Excellent urinary drainage is required for anastomotic healing and the removal of mucous buildup. Suprapubic drainage traditionally involves a Malecot catheter, although poor irrigation and dislodgment of this type of catheter are well-known complications. We report the placement of an intravesical Jackson-Pratt drain for urinary diversion in augmented bladders. MATERIALS AND METHODS: We reviewed our use of an intravesical Jackson-Pratt drain for urinary diversion between 1995 and 1999 in 17 patients. Postoperative catheter drainage and irrigation characteristics were assessed as well as catheter related complications. RESULTS: Average patient age was 13 years (range 3 to 27). The majority of patients underwent ileal (11) or sigmoid (4) cystoplasty and 1 each underwent composite and ureteral cystoplasty. Drains remained in place an average of 27 days (range 6 to 57). All patients had excellent drainage during the postoperative period. Irrigation was subjectively easier than with a Malecot catheter. Average cost of a latex-free Malecot catheter was 2.7-fold that of a Jackson-Pratt drain. No catheters became nonfunctional before removal, although 1 was inadvertently pulled during patient transfer. CONCLUSIONS: A Jackson-Pratt drain provides excellent urinary drainage in patients undergoing augmentation cystoplasty. Multiple openings along the tube seem to improve irrigation in contrast to the single opening in a Malecot catheter, which often aspirates a region of the augmented bladder. The ready availability, decreased cost, ease of irrigation, increased pliability with decreased chance of dislodgment and lack of latex make an intravesical Jackson-Pratt drain a superior choice for augmented neurogenic bladder.

Adolescent↗

PubMed2001

The histopathology of iatrogenic cryptorchid testis: an insight into etiology.

PURPOSE: Iatrogenic undescended testis may develop after inguinal hernia repair, presumably as a result of mechanical tethering of the testis or cord in scar tissue. Because some true cryptorchid testes appear to be completely descended at birth and later ascend during childhood, some iatrogenic undescended testes may be low lying undescended testes. To determine whether iatrogenic undescended testes may be unrecognized cryptorchid testes at herniorrhaphy we examined biopsies of iatrogenic undescended testes and the corresponding contralateral descended testis. MATERIALS AND METHODS: Between 1985 and 1999 bilateral testis biopsies were obtained at orchiopexy in 37 boys 1.5 to 11.8 years old who previously underwent inguinal hernia correction. Histomorphometric analysis of germ cell counts was performed on the undescended and contralateral descended testes, and compared to the count in bilateral biopsies of 37 age and position matched patients with true unilateral cryptorchidism. RESULTS: There were no significant differences in volume or total and differential germ cell counts in the undescended and contralateral descended testes in the study groups and age matched controls with primary unilateral cryptorchidism. The mean number of germ cells per tubule in the undescended testis in patients with a greater than 5-year interval from herniorrhaphy to orchiopexy was significantly decreased compared to those with an operative interval of less than 5 years (0.27 +/- 0.33 versus 0.93 +/- 1.4, p = 0.026). CONCLUSIONS: Some patients with iatrogenic undescended testis may have an unrecognized low cryptorchid testis. Careful physical examination before and after inguinal surgery is recommended. The early repair of iatrogenic undescended testis is warranted to prevent further damage.

Child↗