Takeshi Shono

Transabdominal testicular descent is really ovarian ascent.

Some investigators have suggested that testicular descent relative to the ovary is actually caused by the relative upward growth of the structures adjacent to the testis and that in the early phase of descent the testis is anchored to the inguinal region as the embryo enlarges. This concept was founded on results from the dissection of human fetuses. In this study the development of the urogenital system in fetal mice is examined using scanning electron microscopy to determine the distance between the bladder neck and the lower pole of the gonad. The results of this study confirm that transabdominal descent of the testis relative to the ovary is in one sense really ascent of the ovary in the fetal mouse, while the testis is anchored to the inguinal region by the developed gubernaculum. The testis shows real movement at the beginning of the inguinoscrotal phase of testicular descent at birth.

The effect of flutamide on testicular descent in rats examined by scanning electron microscopy

The effect of prenatal flutamide exposure on testicular descent was investigated by using scanning electron microscopy (SEM) in prenatal and postnatal rats. In 20-day-old fetal rats, SEM showed no significant difference in the degree of gubernacular development or testicular descent relative to the kidney between flutamide-treated (74.5 +/- 2.2 U) and control rats (73.3 +/- 1.5 U); however, there was significant inhibition in oestrogen-treated rats (44.3 +/- 2.2 U) (P < .001). (The distance between the kidney and the bladder neck was standardized to 100 U.) In 5-day-old rats, SEM showed inhibited downward growth of the processus vaginalis in flutamide-treated rats. The length of processus vaginalis below the inguinal ligament was 32.8 +/- 2.4 U in flutamide-treated rats and 51.7 +/- 1.8 U in controls (P < .001). In 30- to 35-day-old mature rats, the frequency of cryptorchidism was 41.3% for flutamide-treated rats and 0% for controls (P < .001). Some cryptorchid testes were located in the lower abdominal cavity (10.9%); others were in the suprainguinal position (26.1%) or on the line of descent in the inguinal region (4.3%). In the flutamide-treated group, no testes were located in the posterior abdominal cavity, near the kidney. These results suggest that transabdominal descent of the testis is independent of androgen action, but that androgens control inguinoscrotal descent of the testis by regulating gubernacular migration and the growth of the processus vaginalis.

Physiological effects in vitro of calcitonin gene-related peptide on gubernacular contractility with or without denervation

The gubernaculum in neonatal rats has been shown previously by direct observation to contract rhythmically in response to exogenous calcitonin gene-related peptide (CGRP), but the physiological properties of these contractions were unknown. In the first study the authors investigated gubernacular contractility in vitro using a strain gauge to see if there were characteristics of skeletal or smooth muscle. Both the frequency and the amplitude of contractions were significantly enhanced by CGRP, and isotonic tension of the gubernaculum and the duration of contractions were also increased after CGRP. The effect of CGRP on gubernacular contractions appeared several minutes after adding CGRP, and it was independent of the acetylcholine action, which induced only a single twitch response of the gubernaculum. In the second study the authors investigated the effect on gubernacular contractility of prior transection of the genitofemoral nerve (GFN), which contains CGRP. Vigorous contractions occurred in 85% of denervated gubernacular compared with 46% of controls (P < .01). These data provide the first quantitative evidence of rhythmic gubernacular contractions, and suggest that CGRP enhances gubernacular contractility by a direct effect independent of acetylcholine. Further, the contractile properties resemble those of differentiated cardiac muscle or primitive embryonic skeletal muscle. GFN transection enhances the gubernacular contractile response to exogenous CGRP, which is consistent with the GFN being the normal source of CGRP for the gubernaculum in vivo.

Capsaicin Increases the Frequency of Cryptorchidism in Flutamide-Treated Rats

Capsaicin, a specific neurotoxin that irreversibly results in degeneration of sensory C fibers of the peripheral nerves, was investigated for its ability to affect testicular descent. In particular, we investigated the ability of prenatal flutamide, postnatal capsaicin or combined prenatal flutamide with postnatal capsaicin to induce undescended testes in rats. Within these treatment groups the frequency of maldescent was 42% in the animals treated prenatally with flutamide, 32% with postnatal capsaicin, and 100% with prenatal flutamide and postnatal capsaicin. Of interest, it was found that all animals that received capsaicin had maldevelopment of the scrotum. Our data suggest that capsaicin increased the frequency of cryptorchidism in rats prenatally treated with flutamide, perhaps by inhibition of scrotal development. These findings indicate that sensory nerves to the scrotum may affect scrotal development and testicular descent.

Right-sided diaphragmatic hernia following group B streptococcal pneumonia and sepsis

A case of right-sided diaphragmatic hernia following group B streptococcal pneumonia and sepsis is reported herein. The clinical course was characteristic. The position of the right hemidiaphragm was initially normal. After an antecedent group B streptococcal infection, an abnormal shadow indicating either pneumonia or a pleural effusion on the chest x-ray was recognized and an elevation of the bowel and liver into the right hemithorax gradually appeared. Repair of the hernia was indicated and the postoperative result was excellent. The relationship between a delayed-onset diaphragmatic hernia and a group B streptococcal infection is still unknown. Increased intrathoracic pressure caused by mechanical ventilation coupled with an abnormal lung compliance due to inflammation may have resulted in the delayed herniation. Among various methods for diagnosis applied, chest x-ray and ultrasonography were noninvasive and useful.