RESUMEN
Bovine bladders at 3 stages during fetal development were examined for expression of collagens by immunohistochemistry as well as by measurement of steady state mRNA levels. Expression of type I and type III collagens during the fetal period was compared with that of adult cows as well as a young animal (heifer). Each bladder was separated into a detrusor and a urothelial-lamina propria sample which were then analyzed separately. Distribution and fiber arrangement of types I and III collagens were different depending upon the region of the bladder wall examined. Type III collagen, in particular, has a "coiled" appearance which is especially prominent within the lamina propria. Collagen gene expression showed a distinctive pattern which was different for both type I and type III collagen. While type I collagen gene expression peaked during the late second to early third trimester, type III collagen expression progressively decreased throughout the fetal period. In addition, expression of both collagens was greater in the urothelial-lamina propria fractions. These data demonstrate that the pattern of collagen gene expression in the developing bladder is developmentally regulated and is unique to each of the two major structural layers.
Asunto(s)
Colágeno/biosíntesis , Colágeno/genética , Regulación del Desarrollo de la Expresión Génica/genética , Vejiga Urinaria/embriología , Vejiga Urinaria/metabolismo , Animales , Bovinos , Espacio Extracelular , Edad Gestacional , ARN Mensajero/análisisRESUMEN
Our experience with hypospadias surgery has changed over the recent five-year period. We are using less preputial tubularized island flaps for urethral replacement and more onlay island flap procedures. Approximately, 20% of hypospadias occurs from the penoscrotal junction to the perineum, while 30% occur in the mid portion of the penis. Fifty percent are distal penile or subcoronal (Figure1). There are different operative procedures to repair these varying types of hypospadias.
RESUMEN
The pathogenesis of the increased incidence of subfertility in cryptorchidism remains controversial, and the concept that the prepubertal testis is a quiescent organ continues to be held by some. Histomorphometric analyses including total and differential germ cell counts and Leydig counts were performed on semithin sections of biopsies from 459 unilateral undescended testes and 356 of their contralateral descended partners in order to further investigate these two issues. The results demonstrate reduced numbers of Leydig cells, delayed disappearance of gonocytes, delayed appearance of adult dark spermatogonia, failure of primary spermatocytes to appear, and reduced total germ cell counts in the undescended testis. These findings support the hypothesis that understimulation of the testis leads to reduced numbers of Leydig cells which leads to delayed and defective maturation of germ cells and reduced total germ cell counts which underlie the increased risk of subfertility in cryptorchidism. The appearance of adult dark spermatogonia in the first year of life and the onset of meiosis at three years of life in the contralateral descended testes contradicts the view that the prepubertal testis is quiescent. Complete evaluation of prepubertal testicular biopsies should include total and differential germ cell counts and Leydig cell counts.