The formal genesis of polymorphnucleated giant cells in the testis has been studied in the rat thioglucose model. The giant cells derive mainly from clumped spermatids (greater than 90%) which have lost their contact to Sertoli cells. The process of spermatogenesis and spermiogenesis as well as the synchronisation of germ cell maturation apparently depend on intercellular bridges of the germ cell populations. Lightmicroscopic findings have shown that with the formation of polymorphnucleated giant cells these links are lost.

Animals↗

PubMedDate not supplied

Possible vascular effects of an LH-RH agonist on the peripheral circulation of the rat testes.

The single injection of an LH-RH agonist caused severe damage to the rat testis within 24 hours. Especially the seminiferous tubules appear to be affected whereby these effects are thought to be secondary to vascular effects of LH-RH agonists.

Animals↗

PubMedDate not supplied

Short-term effects of an LHRH-agonist alone or in combination with testosterone propionate or indomethacin on rat testes. Evidence of testosterone independent effects. I.

The treatment of adult male Wistar rats with a LHRH-agonist (lutrelin Wyeth/WY 40972) resulted in severe damage of the seminiferous tubules as well as in remarkable changes of the blood vessels within 24 hours. First striking signs of alterations within the blood vessels were already found 6 hours after the injection of lutrelin: the blood vessels were almost totally filled with leucocytes. Neither the effects on the germinal epithelium nor the effects on the blood vessels were prevented by the simultaneous treatment with 3 mg testosterone propionate (TP). The treatment with indomethacin, however, clearly antagonized both events. The complete inefficiency of TP to overcome the inhibitory effects of lutrelin on the testes does argue against an androgen deficiency as the primary cause. The results obtained with indomethacin strengthen the hypothesis, that the early deleterious effects of LHRH-agonists on the germinal epithelium of the rat are primarily caused by circulatory disturbances in the testes and that prostaglandins may act as mediators.

Animals↗

PubMedDate not supplied

Coronary perfusion pressure and inflow resistance have different influence on intramyocardial flows during coronary sinus interventions.

A mathematical model is used to represent the vascular bed of the left coronary circulation by an arterial, a capillary and a venous compartment. The model is first adjusted so as to reproduce arterial hemodynamics known from measurements during normal perfusion. Additionally, measurements under coronary sinus occlusion are used to assess the venous section of the model. While the calculated phasic shapes of epicardial flows are seen to agree with measurements, intramyocardial flows, which are inaccessable to measurement, are predicted from the model. The model is run under stepwise changes of coronary perfusion pressure and coronary artery resistance for both the normal state and coronary sinus occlusion. Intramyocardial flow between capillaries and veins, being the main determinant for a possible therapeutic effect of coronary sinus interventions, is estimated.

Animals↗

PubMedDate not supplied

Functional characteristics of optimized arterial tree models perfusing volumes of different thickness and shape.

The relationship between the 'shape of an organ' and the 'cost of blood transport' to perfuse its tissue was evaluated on the basis of optimized arterial model trees simulated to perfuse square-based 100-cm(3) volumes of different shape ('flat' versus 'thick' as defined by the ratio of thickness to side-length h/s < or =1). Specifically, the effects of 'shape' on tree structure, blood transport, and on hemodynamic characteristics were investigated. Branching models of arterial trees were generated by constrained constructive optimization (CCO), based on an identical set of model parameters. All model trees were geometrically and topologically optimized for intravascular volume. Tree structures achieved tremendous savings of blood (transport medium) in comparison to a system of separate tubes. Thickening the perfusion volume (increasing h/s) resulted in a significant decrease of mean transport length, deposition time, and intravascular total volume in the tree. 'Thick' perfusion volumes induced CCO trees to branch more symmetrically into a number of equivalent subtrees repetitiously splitting into smaller ones; 'flat' structures were dominated throughout by a few asymmetrically branching major vessels. In summary, we conclude from systematic variation of shape that thicker perfusion volumes (h/s >0.1) facilitate efficient delivery of blood in comparison to large amounts of 'dead volume' to be carried over long distances in very thin pieces of tissue.

Arteries↗

PubMedDate not supplied

Influence of an aromatase inhibitor (4-acetoxy-4-androstene-3,17-dione) on experimentally induced impairment of spermatogenesis in immature rats.

Subcutaneous treatment of immature male rats with an estrogen precursor, 19-hydroxy-testosterone (19-OHT), at a daily dose of 1 mg/animal for 14 days leads to a significant decrease in the weight of testis, ventral prostate and seminal vesicle. The peripheral levels of LH are lowered. Testicular histology indicates that the effects of 19-OHT are very similar to the known of effect induced by estradiol-17 beta. 19OHT induces a marked impairment of spermato- and spermiogenesis. The maturation division is completely inhibited. The effect of 19-OHT on spermatogenesis is partially reversed by concomitant administration of an aromatase inhibitor (4-acetoxy-4-androstene-3.17-dione, (4-AA] at a dose of 1 mg/animal/day s.c. Meiotic activity is restored, and the weights of genital organs and the serum LH values increase. 4-AA alone has no appreciable effect on the parameters examined in this study. The present results suggest that specific inhibitors of estrogen biosynthesis might not only be useful to investigate the patho-physiological role of estrogens on spermatogenesis, but also be suitable to some extent for the treatment of estrogen-induced infertility in men suffering from idiopathic oligozoospermia.

Androstenedione↗

PubMedDate not supplied

[Animal experimental studies using 19-nor-17 alpha-hydroxyprogesterone caproate (Gestenoroncapronat) with respect to a possible therapeutic application in prostatic adenoma].

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Androgen Antagonists↗

PubMedDate not supplied

[Theoretical and experimental principles and clinical aplications of the antiandrognes (author's transl)].

It is reported the accumulated experience over the last ten years on a synthetic gestegen with a powerful antiandrogenic action: the cyproterone acetate. The effects on androgen dependent processes like: structure and function of genital accesory glands, on skin and sebaceous glands, bone maturation and growth, libido and testicular function are reported, together with the clinical results obtained in the treatment of acne, hirsutism, sexual perversions and as male anticonceptive. The influence of cyproterone acetate on the androgen dependent embrionary processew of differentiation are also discussed as wll as the female anticonceptive action and its effects on other endocrine systems.

Androgen Antagonists↗