The postnatal maturation of regions of the epididymis and intragonadal segment of the deferens duct was studied in the rat by light- and transmission electron microscopy. Maturation of the genital duct starts in the distal cauda epididymidis and ductus deferens after one week of life, and one week later, in the more cranial segments of the epididymis. Epithelial principal cells and peritubular contractile cells are structurally mature 35 days after birth. The synchronous changes of these cells indicate that the same factors control their postnatal maturation. The epithelial principal cells obtain an endocytotic apparatus and long stereocilia, whereas peritubular cells acquire contractile features. These changes are associated with a progressive increase in the immunoreaction for smooth muscle actin in both cell types. Smooth muscle myosin is detected in the apical region of the epithelial cells and the peritubular cell cytoplasm by day one of postnatal development. The differentiation of contractile cells in the wall is accompanied by progressive organization of the pericellular matrix into a continuous basement membrane. Although fibronectin is visible at birth, it is gradually removed from the tubule wall.
A quantitative analysis of Leydig cells was performed in 23 testicular biopsies of men with left varicocele and sperm count ranging from zero to 95,000 sperm/mm3. The oligozoospermic patients had more Leydig cells and higher FSH and LH serum levels than the patient group with more than 10,000 sperm/mm3. The Leydig cell density appeared tightly correlated (p less than 0.01) with the serum level of LH. In oligozoospermic subjects, an altered Leydig cell function could trigger an increased LH secretion; this seems likely to be responsible for the stimulation of interstitial cells resulting in an exaggerated recruitment of mature Leydig cells from their precursors. The comparative analysis of left and right testes failed to show differences in Leydig cell density and spermatogenesis in normozoospermic and oligozoospermic patients. This suggests that the two testes are equally involved by a possible, although unknown, detrimental effect of left side varicocele.
The postnatal maturation of the epithelium and tubule wall of efferent tubules in the rat was investigated by light and transmission electron microscopy, from birth to 50 days of age, when sperms were released from the seminiferous tubules and appeared in the genital duct. At the end of the first week of life, an endocytotic apparatus is differentiated in the epithelial cells. During the third week of life, efferent tubules developed specializations for the transport of sperms and fluids, namely the appearance of ciliated elements interspersed among the principal cells of the epithelium, and differentiation of myoid elements in the tubule wall. The appearance of specializations related to endocytosis and fluid transport across the epithelium preceded the canalization of the seminiferous cords which, in fact, is reported to appear at the end of the second week of life in the rat, along with the initial secretion of testicular fluid. This suggested that the maturation of efferent tubules is not triggered by the passage of testicular fluid, as surmised for the postnatal differentiation of caput epididymis. The postnatal maturation of efferent tubules was almost complete 35 days after birth. The appearance of sperms in the genital duct of 50-day-old animals was not associated with any remarkable structural change.
Mutations in the MYBPC3 gene, which encodes myosin C–binding protein C (cMyBP–C) are among the main causes of hypertrophic cardiomyopathy (HCM). Truncating mutations are recognized as causative in many HCM patients and recently, even missense mutations (e.g E258K mutation) appear to be clinically related to the disease. E258K is one of the most common MYBPC3 mutations, with a prevalence of 15% in Italians. We report a family case, with father and son affected by HCM in which where this mutation was identified thanks to the NGS. HCM in the father was diagnosed at the age of 70 after several episodes of atrial fibrillation and after a myocardial infarction. The son, a sportsman, had a very early and severe presentation of HCM in the absence of manifest clinical signs. The same E258K mutation was also found in the proband son, in the absence of clinical signs of HCM. Given the diversity of the carrier phenotypes, the molecular analysis of the proband was extended beyond rare variants and we found a common substitution in the DES gene, (encoding desmin) which, acting as an unfavourable modifier, could partly explain the different clinical presentation of HCM. Probably also the intense physical activity carried out by the proband contributed to the phenotype severity. The father, asymptomatic for a much longer period and with a lower hypertrophy grade compared to the proband, may have benefited from a less intense physical activity and from the absence of the DES polymorphism. To date, the role of physical exercise is widely debated: on the one hand, a regular intense physical training could worsen hypertrophy, fibrosis and trigger arrhythmias, on the other hand however, a sedentary lifestyle predisposes to obesity and other cardiovascular risk factors which induce diseases with a worse prognosis than HCM itself. Nowadays 70% of patients with HCM are overweight, and more than 50% are below the minimum recommended exercise threshold. In addition, there is growing evidence that competitive sports are safe and could have beneficial effects in asymptomatic low–risk HCM patients. This case study suggests that the decision–making process must include both genotypic and phenotypic characterization of patients, as well as the evaluation of the causative mutation pathogenicity and of co–existing genetic modifiers.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.