Seminiferous Epithelium Cycle in the Armadillo

The spermatogenesis of the hairy armadillo was studied. Four spermatogonial types were identified: A+ (with PAS-positive granules, presumably the stem cell). A, In. and B-similar to the situation in the rat. Spermiogenesis could be subdivided into the four classical phases. comprising 14 steps of spermatid evolution. Eleven stages of the cycle are identified. © 1983, Informa UK Ltd. All rights reserved

Seasonality and freezability vs routine parameters in stallion semen

The fertilizing ability of stallion semen was analyzed using fresh and frozen samples, obtained before (June-July) or during (October-November) the breeding season. Thirty ejaculates obtained from 4 stallions, were used. The analysis comprises routine seminogram; ATP concentration (Comhaire et al., 1983); subjective and objective motility and sperm velocity (Makler, 1980). Freezing was done following the technique of Martin et al. (1979). Sperm velocity, ATP content and objective motility in ejaculates of subjective motility >50% show values of 14.010.84 ym S-l; 4.8f 2 . 7 1~O - ~ Man d 54.0I7.4%, respectively. For ejaculates with subjective motility ~ 5 0 %the~se values are 8.412.4; 0.74f 0 . 3 6 1~ 0 - 7 a~n d 27.0+0.8%. No significant changes in these characteristics were elicited by freezing, though ATP content dropped to 50% after thawing. These characteristics are highly associated between them (pc0.05) and with some conventional parameters of the routine seminogram such as sperm motility, count, total spermatozoal number and morphology. Additionally, sperm chromatin packing was analyzed by decondensing sperm nuclei using a thiol reducing agent. This parameter was not modified by freezing and it may depend on prolonged epididymal sperm storage during the non-breeding season. Epididymal maturation then results in an excessive disulphur bridging in sperm basic proteins, so that hypermaturation with faultly male pronuclear formation can follow

The rete testis in man: Ultrastructural aspects

The ultrastructure of the normal human rete testis was analyzed. The rete testis cavities are irregularly shaped and contain virtually no spermatozoa. Smooth muscle cells often surround the cavities. In the epithelial lining, two cell types are distinguishable. Flat, dark cells exhibit numerous slender microvilli, and numerous apical and basal microvesicles. Prismatic, lighter cells have more cell organelles, mostly polarized towards a supranuclear position. Both cell types contain variable amounts of glycogen and fat, and an occasional cilium. All cells display intricate lateral cell surfaces that possess different cell-to-cell attachment devices. Intermediate cell types are frequently found. On a morphological basis, the epithelial cells seem to be involved in the release of substances into the lumen and probably also in transport towards the base. Connective tissue elements are found subjacent to the epithelium. Scattered among the fibrocytes are typical smooth muscle cells. Expans

Cytological characterization of the germinal line during testicular differentiation in the lizard Liolaemus gravenhorsti (gray)

The gross morphology, histology, and ultrastructure of Liolaemus gravenhorsti gonads prior to and after differntiation are described. Special emphasis has been given to characterization and changes of the germ cell line throughout intrauterine development and 3 days postpartum. During the pregonadal stage, the primordial germ cell migrates toward gonadal rudiments by way of the mesenchyme. These cells can easily be identified by their great size, voluminous and lobulated nucleus, great quantities of yolk platelets, microtubules, and numerous lipid inclusions. In the undifferentiated gonad, the germ cells (type 1 gonocytes) have an ovoid or spherical shape and autodigestion of yolk platelets, great development of Golgi complex, and mitochondrial aggregation, though fewer liposomes, pseudopodes, and microtubules were noted. Concomitantly with the beginning of mitosis, a third type of germ cell appears, the type 2 gonocytes, which are smaller, with poorly defined membranous systems in va

Experimental hypercholesterolaemia in rabbits. Effect on lipid domains in homologous spermatozoa

The distribution of membrane filipin sterol complexes (FSC) in the plasma membrane of the acrosomal region (PMAR) of rabbit sperm from epididymis and testis, in normal and hypercholesterolaemic rabbits, was examined at ultrastructural level. Membrane FSC were quantitatively analysed on freeze fracture replicas of filipin-treated cells. Cauda epididymal sperm shows a significant increase in filipin sterol complexes concentration in PMAR of hypercholesterolaemic animals compared to normal rabbits. Hypercholesterolaemic animals had 0.53 ± 0.08 FSC μm-2 in the marginal segment of PMAR and 0.26 ± 0.03 FSC μm-2 for normal animals. In the principal piece we found 0.70 ± 0.07 FSC μm-2 for hypercholesterolaemic and 0.43 ± 0.03 FSC μm-2 for control animals. We also counted 0.58 ± 0.04 FSC μm-2 in the equatorial segment of PMAR for hypercholesterolaemic and 0.38 ± 0.03 FSC μm-2 for normal animals respectively. The FSC concentration of testicular sperm, like sperm from corpus and caput of epididy

Fertilizing capacity of human spermatozoa evaluated by actual penetration of foreign eggs

A system utilizing zona-free hamster oocytes, briefly preincubated, uas used to evaluate the ability for fertilization of human spermatozoa from infertile or normal individuals. Phase-contrast and electron microscopically determined decondensation of the sperm head uas taken as evidence for sperm entry. Forty-one cases were catalogued as fertile (according to the spermiogram) but only 31 (76%) gave a positive sperm entry test. On the other hand, 13 out of 38 (34%) suspected infertile cases also gave a positive test. This bioassay is of potential interest in the investigation and treatment of male infertility as well as for evaluation of the fertilizing ability of human spermatozoa as related to male contraception. © 1978

Epiblast embryo stem cells give origin to adult pluripotent cell populations: Primordial germ cell, pericytic and haematopoyetic stem cells. A review Las células madre del epiblasto dan origen a poblaciones de células pluripotentes adultas: Células germin

Adult stem cells are great promise to the future of regenerative therapy, and understanding of its embryonic origin permit the discrimination of stem cell sources. Embryonic stem cells derived from inner cell mass of blastocyst originate the primordial germ cells, and pericyte stem cell associated to vessels endothelium in yolk sac. Currently, it is being proposed that embryonic primordial germ cell could originate hematopoietic stem cells based on the detection of germ cell markers (SSEA-1/TEC-1, Oct-4 and Nanog) in stem cell harvested from fetal liver and bone marrow. However, different experimental evidence points at two separate differentiation routes toward primordial germ cells, and hematopoietic stem cell with the same embryonic origin. The expression of undifferentiated stem cell markers in umbilical cord and placental vessels, such CD34, CXCR4, c-kit and OCT4 demonstrates the intimate relation between pericyte stem cells, endothelium, haematopoiesis, and primordial germ cells

Morphology of testis and epididymis in an ethanol-drinking rat strain (UChA and UChB)

The objective of the present study was to analyze the prospective alterations of the testis and epididymis in a defined strain of alcoholic rats in order to contribute to our understanding of the effects of chronic alcoholism on reproduction. The testis and epididymis of the animals were submitted to morphological analysis by macroscopy, light microscopy and electron microscopy and to morphometric analysis. The UCh rats showed atrophy of the epithelium and reduction of testis and epididymis weight, liver hypertrophy and fat infiltration and alterations of the hypothalamus-pituitary axis. Ethanol induces changes in the weight and in the epithelium of the testis and epididymis and in the hypothalamus-pituitary axis of the UCh rats