The existence of different stages of postnatal activities in Leydig's cells, as demonstrated in hormone studies, appears to be fully admitted. Such occurrence should have repercussions on the population of those elements primarily entrusted with their production, either in the number of elements or their activities. The present article studies Leydig's cells rate in Wistar rats over the postnatal stage, from birth to adulthood. During this postnatal stage, Leydig's cells population does not actually disappear. There is a decrease immediately after birth and up to the age of 21 days when gonadal drop occurs in this species, and from there on a considerable increase takes place for in a two-month period they multiply by ten. On the other hand, it is highly surprising the great speed of testicle growth up to the age of 60 days, reaching maximum size at 90 days. The increase is due to the growth of the tubular compartment.

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[Application of transmission and scanning electron microscopy in experimental obstructive uropathy: I. Glomerular lesions].

In this research we use the Electronic Transmission and Sweep Microscope to study the morphostructural modifications undergone by the renal glomerulus in experimental obstructive uropathy. The most significant alterations take place at the level of the basal lamina of the glomerulus, where progressive thickening anf folding occurs. The podocytes display, mainly in the late groups, loss of the digit-shaped character of their secondary prolongations, with shortening and thickening of these. They also take on an anarchic arrangement and are pseudofused to one another, forming a cellular lamina in contact with the underlying basal membrane. These morphostructural changes justify the reduction in glomerular filtration that takes place in obstructive uropathy.

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[Application of transmission and scanning electron microscopy in experimental obstructive uropathy: II. Tubular lesions].

The morfoestructural changes that appear at renal tubule level in obstructive uropathy consist in a progressive loss of the differentiations in the plasmatic membrane: reduction in the number of apical microvilli and of basal invaginations, which entails a drop in the exchange surface area. Degeneration and cellular necrosis phenomena also exist, with the appearance of cell traces in the tubule lumen. On the other hand, morphological signs of a rapid rate of cellular activity in the tubule cells are displayed. Together with the modifications that take place at basal membrane level these changes give rise to an alteration of tubule dynamics.

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[Application of transmission and scanning electron microscopy in experimental obstructive uropathy: III. Lesions at the interstitial level].

In experimental obstructive uropathy the renal interstice undergoes profound modifications, from the earliest stages, with the fibroblastic elements adopting a palisade arrangement between the renal tubules and the blood cells. Between these cells there is a marked edema configuring "canals", which could be the morphological image of the tubulovenous reflux described in obstructive uropathy. these routes, which we will call tubule-interstice-vein "canals", since in no case could we verify the existence of a direct communication between the tubule formations and the veins, disappear in animals put down late, where fibro and myofibroblastic elements, round cells and macrophages proliferate. A larger number of fibres and fundamental substance are also found. As a result of these changes, a great alteration in renal architecture takes place.

Animals↗

PubMedDate not supplied