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At least 127 records · Page 7Linked to original sources

Dynamic magnetic resonance imaging of the contralateral testis in patients with malignant tumor of the testis.

OBJECTIVES: Dynamic magnetic resonance imaging (MRI) was tested using a dynamic technique to evaluate the possibility of differentiating between normal contralateral testes and testes with a carcinoma in situ. METHODS: Since March 1990, 20 volunteers and 21 patients with a malignant tumor of the testis were examined in a field strength of 1.5 Tesla (Philips Gyroscan S15) with a multislice T1-weighted fast field echo sequence before and every 63 seconds after the injection of 0.1 mmol/kg gadolinium-diethylenetriamine pentaacetic acid. RESULTS: Significant differences (p < 0.001) in signal changes of contralateral testes were detected in dynamic MRI. This increased signal enhancement is detected even 45 months after orchiectomy in the contralateral testes. The signal increase is reduced in follow-up controls. These observations are explained by an increased perfusion which seems to be induced after a postoperative irritation, an unspecific inflammation, or postoperative bleeding. CONCLUSIONS: To avoid false-positive diagnoses of tumors or carcinomata in situ in contralateral testes, these increased enhancements caused by postoperative reactions have to be kept in mind.

Adult↗

Central effect of rete testis fluid, inhibin 32K, and follicular fluid on plasma gonadotropin concentrations in sheep: inhibin is not the rete testis fluid protein able to suppress luteinizing hormone pulses.

We have previously shown that peripheral administration of rete testis fluid (RTF) proteins was able to suppress LH pulses through the suppression of LHRH pulses. This activity was named "LHRH Statin." The aims of the present work were to analyze LH inhibition after an intracerebroventricular injection of RTF and to determine whether inhibin is the factor responsible for this inhibition. Castrated rams (experiment 1) or ewes (experiment 2) received an intracerebroventricular injection of RTF, purified bovine inhibin 32K, bovine follicular fluid, or human serum albumin as control. Animals were bled every 15 min for 5 h before injection and for 7 h after injection. LH mean levels were significantly lowered (p < 0.01) only in the RFT-treated groups. FSH levels were not affected irrespective of group, source, or dose of inhibin. These experiments show first, that protein(s) present in ovine RTF can suppress LH secretion in sheep; second, that bovine follicular fluid or purified bovine inhibin 32K have no effect on LH secretion. Furthermore, the results suggest that centrally administered inhibin has no effect on FSH secretion under our experimental conditions. Together, these experiments clearly demonstrate that inhibin 32K does not exert any "LHRH statin" activity.

Animals↗

Restoration of advanced spermatogenic cells in the experimentally regressed rat testis: quantitative relationship to testosterone concentration within the testis.

We examined the effect of exogenously administered testosterone (T) on the quantitative restoration of advanced spermatogenic cells in adult rat testes rendered azoospermic by treating rats with polydimethylsiloxane (PDS) implants of T and estradiol (E). Experimental rats received PDS-TE implants for an initial 8-week period; control rats received empty implants. By 8 weeks of PDS-TE treatment, rats became severely oligospermic, and the T concentration within the seminiferous tubule fluid (STF) was reduced approximately 80% (from 57.8 ng/ml in controls to 9.6 ng/ml). After the initial 8-week PDS-TE treatment, PDS-TE implants were removed from one group of rats; a second group of PDS-TE-implanted rats received an additional PDS-T implant of 24 cm. Eight weeks after the removal of PDS-TE implants or the implantation of additional T, testis weight and numbers of advanced spermatogenic cells were restored to those of control rats. The STF T concentration 8 weeks after the removal of PDS-TE implants also was restored to that in control rats. In contrast, the STF T concentration increased to only 40% of control values in the rats that received an additional T implant. Despite this 60% reduction in T concentration compared to the control value, advanced spermatogenic cell number was restored to a value indistinguishable from that of intact controls. These observations indicate that spermatogenesis can be quantitatively restored in PDS-TE-implanted rats with exogenously administered T, and moreover, that this restoration does not require the high T concentration found in the STF of intact control rats.

Animals↗

Studies of the human testis. X. Properties of human chorionic gonadotropin receptor in adult testis and relation to intratesticular testosterone concentration.

Receptors for [125I]hCG were found in adult human testis. The specific binding of [125I]hCG to testicular receptor is temperature dependent and is a saturable process with respect to added receptor protein and hormone. Scatchard analysis revealed a dissociation constant of 5.0 X 10(-10) M, and 6.2 fmol binding site/mg protein. Intact unlabeled hCG effectively inhibits the specific binding of [125I]hCG to human testicular receptors. For inhibition of binding of [125I]hCG, the alpha subunit has 3.0% of the potency of intact hCG and the beta subunit has 0.4% of the potency of intact hCG. Specific binding is pH dependent, with an optimum at pH 7.4. Brief exposure to extremes of pH causes irreversible damage to the receptors. Incubation with protease and trypsin results in an almost complete loss of binding activity, while ribonuclease, deoxyribonuclease, phospholipase C, or neuraminidase treatment does not significantly alter hormone-binding activity. Binding activity was found to be positively correlated to the concentration of intratesticular testosterone.

Adult↗

Testicular DNA synthesis in vivo: comparison between unilaterally cryptorchid testis and contralateral intact testis in mouse.

DNA synthetic activity was studied by autoradiography in unilaterally cryptorchid (abdominal) and contralateral intact(scrotal) testes in mice. Nongerm cells were inactive in DNA synthesis in both the cryptorchid testis and in the intact control. Labeling indices of undifferentiated type A spermatogonia did not show any differences, indicating that type A spermatogonia did not temperature sensitive in DNA synthesis in vivo.

Animals↗

Kinetics of the enzymatic pattern in the testis. I. Stage dependence of enzymatic activity and its relation to cellular interactions in the testis of the Wistar rat.

The "morphology" of the enzymatic activities of thiamine pyrophosphatase (TPPase), acid phosphatases (ACPases), adenosine triphosphatase (ATPase) and steroid-3 beta-ol dehydrogenase (St-3 beta-ol DH) has been described using as a basis the classification of the seminiferous epithelium of the rat into 14 stages as proposed by Leblond and Clermont (1952a, b). It was demonstrated (Figs. 1, 2) that 1. the kinetics of the enzymatic pattern is correlated with the developmental stages during spermatocyto- and spermiogenesis, and that therefore the chemocytostructure, especially of the germ cells, shows characteristic changes. 2. the enzymatic pattern yields information on the chemohistostructure of the testis, and thus indicates interactions between the germ cells and the coordinated somatic cells. This is valid especially for the behaviour of the "marker enzymes" TPPase and ACPases. Initially the activity of both enzymes is distributed in the cytoplasm: TPPase appears in stage VII in the preleptotene spermatocytes, and ACPases appear in stage VII in the pachytene spermatocytes. In the following stages the activity of TPPase and ACPases increases and becomes more and more concentrated, i.e. from stage IX to XIV and thereafter from stage I to XIII in the case of TPPase, and from stage I to XIII in the case of ACPases. Finally the enzymatic activity of both TPPase and ACPases is arranged in spherical bodies near the nucleus of the spermatocytes. Thus the late pachytene and diplotene spermatocytes, as well as the spermatocytes in diakinesis, are characterized by deeply stained spherical dots covering the region of the Golgi apparatus. Both enzymes disappear during the maturation divisions--parts of the cytoplasm of the II-spermatocytes during interphase react weakly positive--, reappear in the Golgi region of the newly formed spermatids in stage I, remain there up to stage V in the case of ACPases, and up to stage VII in the case of TPPase. From stages VIII to XIV TPPase is weakly positive in the Golgi apparatus of the elongating spermatids, moving within the cytoplasm from the head region towards the tail. Finally they appear in the cytoplasm of the Sertoli cells: (1) ACPases appear in the borderline region between the Sertoli cells and the elongated spermatids in stages XII to XIV (2) TPPase first appears in the basal region of the Sertoli cells in stages XI to XIV, and becomes positive in the subsequent stages I to IV as "streamer like" bands from the basement membrane up to the heads of the elongated spermatids. Both enzymes disappear gradually during stages I to III and IV to V respectively. Stage dependence of ATPase can be observed in the apical region of the Sertoli cells around the heads and the middle pieces of the elongated spermatids. ATPase appears for the first time in stages IX to X, and becomes increasingly more and more concentrated and condensed up to the point when the newly formed spermatozoa are released in stage VIII...

3-Hydroxysteroid Dehydrogenases↗