C. J. G. Wensing

Testis volumes, semen quality, and hormonal patterns in adolescents with and without a varicocele.

OBJECTIVE To study the effects of varicocele on testicular function in adolescents. DESIGN A prospective controlled study in 88 randomly selected adolescents. SETTING All participants were referred to the fertility outpatient clinic of our University Hospital. PARTICIPANTS All participants with a grade II varicocele (group 2) or a grade III varicocele (group 3) were selected at a district military medical council, whereas a similar group of healthy volunteers without a varicocele served as controls (group 3). INTERVENTIONS Testis volumes were measured using an orchiometer. Semen analysis was performed according to standard procedures, and serum hormone levels were determined using a radioimmunoassay. MAIN OUTCOME MEASURE(S) Testis volumes, semen quality, and hormonal parameters in adolescents with and without a varicocele were compared. RESULTS In group 1 (n = 21), the mean left testis volume (24.5 mL; 95% confidence interval [CI]: 22.8 to 26.2) was significantly (P less than 0.05) different from group 2 (n = 15) (20.9 mL: 95% CI: 18.5 to 23.4) and group 3 (n = 52) (20.7 mL; 95% CI: 19.2 to 22.2) (P less than 0.01) adolescents. In adolescents with a pronounced varicocele-associated left testicular growth failure, the total sperm number was reduced. However, sperm concentration, motility, and morphology were not altered. Luteinizing hormone, follicle-stimulating hormone, testosterone, and prolactin levels were all within the normal ranges in the three groups. CONCLUSIONS Left testicular growth failure in adolescents with a varicocele is only associated with a decrease in total sperm number.

Turnover time of Leydig cells and other interstitial cells in testes of adult rats.

The aim of this study was to investigate the turnover of Leydig cells and other interstitial cells in the adult rat testis. Normal adult rats received injections of [3H]thymidine at 9:00 and 21:00 for 2, 5, or 8 days. The percentage of labeled Leydig cells, which was initially low (0.8% +/- 0.2%), gradually increased during treatment to 1.4% +/- 0.3%. The percentage of labeled peritubular cells was considerably higher and increased from 1.4% +/- 0.1% to 3.5% +/- 0.4% during [3H]thymidine treatment. The remaining interstitial cells were the most actively proliferating cells: the percentage of labeled cells increased from 2.4% +/- 0.2% to 7.5% +/- 0.8% during [3H]thymidine treatment. Leydig cells, peritubular cells, and the remaining interstitial cells in the adult rat testis undergo proliferation. By means of a linear regression analysis and an arcsin transformation, an estimation of the time interval needed to replace various types of interstitial cells was obtained. Taking into account the 95% confidence interval, the turnover time of Leydig cells ranged from 142 to 2823 days. The calculated turnover time for the peritubular cells was 85 to 257 days.

The effects of gestational age and chronic fetal decapitation on arterial blood pressure in the pig fetus.

Blood pressure was measured in anaesthetized pig fetuses decapitated at 40-43 days of gestation and in intact fetuses between 35 and 112 days of gestation (term is 114 days). In the intact fetuses arterial blood pressure increased significantly from 0.8 +/- 0.1 kPa (mean +/- SEM) at 35 days to 5.8 +/- 0.2 kPa at 112 days (P less than 0.05). The arterial blood pressure of decapitated fetuses was similar to that of intact fetuses at 70 days of gestation (2.7 +/- 0.4 kPa vs. 2.5 +/- 0.1 kPa, respectively) but did not change with increasing gestational age thereafter. Hence in late gestation (greater than 90-100 days) the arterial blood pressure of the decapitated fetuses was significantly less than that of intact fetuses (P less than 0.05). These observations demonstrate that the control of blood pressure in the pig varies with gestational age and suggest that the developmental changes occurring after about 100 days gestation require tissues within the head.

Protective effect of hypoxia in the ram testis during single and split-dose X-irradiation

Spermatogonial stem-cell survival in the ram was studied after single (6 Gy) and split-dose (2 x 3 Gy, interval 21-24 h) X-irradiation both under normal and hypoxic conditions. Hypoxia was induced by inflation of an occluder implanted around the testicular artery. The occluders were inflated about 10 min before irradiation and deflated immediately after. Stem-cell survival was measured at 5 or 7 weeks after irradiation by determination of the Repopulation Index (RI) in histological testis sections. The RI-values after fractionated irradiation were only half those after single dose irradiation. Hypoxia had a protective effect on the stem-cell survival. After split-dose irradiation under hypoxic conditions two times more stem cells survived than under normal oxic conditions; the RI-values increased from 34% (oxic) to 68% (hypoxic). This effect of hypoxia was also found after single dose irradiation where the RI-values increased from 68% (oxic) to 84% (hypoxic). The development of the epithelium in repopulated tubules was also studied. Under hypoxia, a significantly higher fraction of tubules with complete epithelium was found after single (38 vs. 4%) as well as after split-dose irradiation (12 vs. 0%).

Nerve endings in the pulmonary trunk, ductus arteriosus and aorta of intact and decapitated pig fetuses

SummaryNerve fibres reactive to acetyl-thiocholine, and tissues showing catecholamine fluorescence were examined in the pulmonary trunk, ductus arteriosus and aorta of 28 pig fetuses between 31 and 113 days of gestation (term=114±1 days). Eight additional fetuses, which had been decapitated in utero at 40–43 days, were also studied at ages between 51 and 114 days of gestation. Spherical micro-networks of nervous tissue reactive to acetyl-thiocholine are present in the adventitia on the cranial aspect of the pulmonary trunk and ductus arteriosus, between the aorta and pulmonary trunk, and on the caudal aspects of the pulmonary trunk and the pulmonary arteries. These fibres invest spherical clusters of catecholamine containing cells which are well supplied with blood vessels. Nerve fibres which fluoresce are also found in association with these cells. Decapitation in utero does not appear to affect the distribution or morphology of these structures. The observations show that structures are present in the major arteries of the fetal pig which may act as sensory receptors, and that these structures are unaffected by chronic vagotomy of the fetus produced by decapitation early in gestation.

Protection of spermatogenesis against cytotoxic effects of two chemotherapeutic drugs by temporary testicular blood flow interruption in the ram

Summary. Temporary interruption of the testicular blood flow for 1 h after injection of cytostatic drugs has a protective effect on spermatogenesis. This was shown in experiments in which spermatogenesis was evaluated at four weeks after a single intravenous injection of AdriblastinaR (ADR; doxorubicine hydrochloride) or Mitomycin‐C‐kyowaR (MIT). Interruption of the blood flow was performed by inflation of an occluder implanted around the testicular artery.

Repeated interruptions of the testicular blood flow do not have long-term effects on spermatogenesis in the ram

Summary. The effect of repeated interruptions of the testicular blood flow on spermatogenesis was studied in mature Texel rams. Reversible interruption of the blood flow was achieved by an inflatable occluder, placed around the testicular artery at the level of the spermatic cord. In eight testes the blood flow was successfully interrupted six times for 1 h within 3 weeks and in 14 testes nine times for 1 h within 3 weeks. Nine weeks after the last blood flow interruption spermatogenesis was evaluated in histological sections of the testes. Both after six and nine blood flow interruptions a qualitatively complete epithelium was found in at least 90% of the seminiferous tubules. Cell counts in stages VII and VIII of the spermatogenic cycle revealed a slight decrease of spermatocytes and spermatids in the tubules with a complete epithelium after nine occlusions, which was only statistically significant for Preleptotene Spermatocytes. After six occlusions the numbers of all cell types were at or even slightly above control levels. These results show that repeated periods of ischaemia for 1 h do not result in conspicious long‐term damage to spermatogenesis.

Catecholamines in fetal pig plasma and the response to acute hypoxia and chronic fetal decapitation

SummaryDopamine, norepinephrine and epinephrine were measured by radioenzymatic assay in blood plasma samples drawn from the umbilical arteries of 30 anaesthetised Landrace pig fetuses. Just prior to term, the concentrations of dopamine (0.46±0.14 ng·ml−1) and norepinephrine (1.74±0.60 ng·mg−1) were lower than earlier in gestation, whereas epinephrine concentrations at term (0.80±0.31 ng·ml−1) were similar to those at mid-gestation, intervening stages of gestation having higher levels of plasma epinephrine. Fetal hypoxia was induced by clamping the umbilical cord for 2 min and the catecholamines determined in arterial blood samples immediately thereafter, then again 3 min after removal of the clamp. Inconsistent effects of cord clamping on catecholamine levels were seen at 55 days, but thereafter, in all but one instance, the hormone levels were increased. Fetuses near term tended to respond less than fetuses at 75 and 96 days gestation (term=114±1 day). Catecholamines were also present in the circulation of fetuses decapitated at 42 days gestation and studied at 109±1 days. The average concentrations of dopamine (1.12±0.27 ng·ml−1) and norepinephrine (8.23±3.04 ng·ml−1) were greater than in intact fetuses, the plasma epinephrine levels being comparable to, or slightly higher than, those in intact fetuses. The results demonstrate that catecholamines are present in the circulation of the intact and decapitated pig fetus and that the actual concentrations and the type of response to umbilical cord clamping are dependent on gestation age.

Development of nervous tissue in the heart of the fetal and neonatal pig and the effect of decapitation in utero

SummaryThe development and distribution of the nerves in the heart of the pig was studied macroscopically and by light microscopy. Hearts were collected from 86 fetuses between 31 and 114 days of gestation (term=114 days), from 12 neonatal pigs aged 9 and 20 days and from 6 adult sows of the Dutch Landrace breed. The effect of vagotomy produced by decapitation in utero at 40–43 days was studied in an additional 24 hearts from fetuses aged between 51 and 114 days of gestation. The amount of acetyl-thiocholine reactive fibres increases in the atria, A-V node and ventricles throughout gestation. At every age the amount of nervous tissue is highest in the A-V node and lowest in the ventricles. Hearts from decapitated fetuses have smaller amounts of nerve tissue than those from intact fetuses at every age studied. Ganglia are present in both intact and decapitated fetuses. Fluorescent cells containing catecholamines are observed in hearts from fetuses as young as 35 days gestation. Although fluorescent nerve fibres are rarely seen in hearts at 70 days gestation, more fibres are present near birth and thereafter there appears to be a considerable increase in the number of fibres and in the intensity with which they fluoresce.These results show that there is substantial nerve growth into the heart of the pig during gestation and that catecholamine containing nerve fibres develop later than those reactive to acetyl-thiocholine.