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Biomedical subjects

H Themann

Publications and source records attributed to H Themann.

174 records · Page 10Linked to original sources
PubMedDate not supplied

Reversibility of long-term effects of GnRH agonist administration on testicular histology and sperm production in the nonhuman primate.

The present investigation evaluates the long-term effects of GnRH agonist treatment on testicular histology, sperm production and the subsequent recovery of these parameters. Four adult rhesus monkeys (M. mulatta) were treated with the GnRH agonist nafarelin (D-Nal(2)6-GnRH), released from i.m.--injected poly-D,L-lactic-co-glycolide microspheres for 20 months. Monthly injection of the GnRH agonist preparation uniformly suppressed serum levels of bioactive LH and testosterone. The size of the testis was reduced to about 30% of pretreatment. Sperm counts were suppressed to azoospermia for a total period of 53 and 77 weeks, respectively, in two monkeys and the other two animals were extremely oligozoospermic. Evaluation of testicular biopsy material after 6, 12 and 20 months of treatment revealed decreased seminiferous tubule diameter, spermatogenic disruption at the level of spermatogonia or spermatocytes, accumulation of lipid droplets and secondary lysosomes in the Sertoli cell cytoplasm, and increased thickness of the tubular wall compared with pretreatment histology. Electron microscopic examination revealed that the increased wall thickness was due to an enlargement of the inner collagen layer. No evidence of fibrosis or calcification could be obtained. Leydig cells were atrophic. Serum hormones, testis size and sperm counts returned to pretreatment values within 5 to 8, 13 to 16, and 18 weeks, respectively, after termination of treatment. Testicular histology, assessed 8 months after cessation of treatment, was indistinguishable from pretreatment. It is concluded that GnRH agonist-containing microspheres are a feasible modality for sustained administration of GnRH agonists and GnRH agonist-induced suppression of pituitary and testicular function is reversible following withdrawal of treatment. Thus, GnRH agonists may have a potential for regulation of male fertility and, presumably, also for treatment of precocious puberty.

Animals↗
PubMedDate not supplied

[Alcohol in pregnancy and fetal heart damage].

Alcohol abuse and addiction during pregnancy can induce damage of the heart muscle and heart defects in the offspring. Between 1973 and 1991 216 children with fetal alcohol syndrome were diagnosed and examined for congenital heart defects. In 63 children (= 29,1%) heart defects were present, established mainly by heart catheterization and/or echocardiography. Most frequently ventricular septal defects (24/63) and atrial septal defects (23/63) occurred, less frequent were AV-defects (3), PDA (3), Fallots teralogy (5), and other malformations (5). Biopsy during heart surgery in 3 children revealed histological and electron microscopic changes of alcohol-cardiomyopathy. Heart defects are predominantly found in children with higher degree of severity concerning the clinical syndrome, less frequently in alcohol effects (4/38 = 11%). Alcohol in pregnancy, even in the course of so called social drinking, usual drinking and binge drinking has to be considered as an essential and preventable co-factor within the multifactorial etiology of congenital heart defects.

Adolescent↗
PubMedDate not supplied

[Electron microscopic findings in a polyneuropathy complicating panarteritis nodosa].

Electromicroscopial changes were observed in arterioles, nerves, and striated skeleton muscle cells in a case of clinically and histologically definite polyarteritis nodosa with polyneuropathy. Inflammatory infiltrates were found in and around arteriolar walls; motor nerves were partly demarkated and presynaptic motor endplates were degenerated. The myofibrills of skeleton muscle cells showed a disorganization that is regarded as the morphological substrate for the clinically observed muscular weakness in this case.

Aged↗