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Biomedical subjects

H Feder

Publications and source records attributed to H Feder.

At least 19 recordsLinked to original sources
PubMed1992

Neonatal prazosin exposure reduces ovarian weight and estrogen receptor binding in adult female rats.

Exposure of estrogen treated adult female guinea pigs to the alpha-1 antagonist prazosin has been shown to reduce levels of estrogen binding in the hypothalamus and preoptic area. To further investigate this interaction between the noradrenergic and neuroendocrine axes, newborn female rat pups received an s.c. implant of prazosin (0.0125 mg/day for 5 days) or placebo. In adulthood, subjects were sacrificed by perfusion with DMSO on the morning of proestrous. Tissue analysis of the medial preoptic area, corticomedial amygdala, and mediobassal hypothalamus revealed that cytosolic estrogen binding was significantly reduced in all three areas for the prazosin treated group as compared to controls. Ovarian weight was also significantly reduced in the prazosin treated group, although uterine weight was unaffected. Interestingly, prazosin treated females showed a post-pubertal increase in body weight characteristic of ovariectomized females, while controls showed no such increase. These results support the existence of a significant developmental interaction between the noradrenergic system and the neuroendocrine axis as measured by ovarian weight and estrogen binding in the brain.

Animals↗
PubMed1984

Hypothalamic and preoptic area alpha 1-receptor concentrations decrease, and cerebral cortical alpha 1-receptor concentrations increase during postnatal maturation of male guinea pigs.

alpha 1-Receptors were measured in intact male guinea pigs during the course of postnatal development. Receptor concentrations were significantly higher at day 1 in hypothalamus and at days 1 and 14 in preoptic area than at day 60. Conversely, in cerebral cortex, receptor concentrations were significantly lower in neonatal animals than in 60-day-old animals. There was no change in affinity of the receptor during development. Castration has no apparent effect on alpha 1-receptor concentration in any brain area.

Animals↗
PubMed1976

[Some mechanical properties of the pig aorta (author's transl)].

In a machine for tensile tests the ultimate strength, stress and strain of the aorta ascendens of 47 female pigs (German landrace) at three different regions of the vessel wall were determined. The animals were fattened under identical conditions in a progeny testing station and slaughtered at the same living weight (102 +/- 2 kg). Weak regressions of body weight and age on parameters measured were nevertheless accounted for. The average elastin content of the aorta ascendens diminished with advancing age but was not significantly correlated to biomechanical properties of the three single samples. Maximum load, stress and modulus of vessel wall segment I (stamped out nearer to the heart) was greater than in sample II. These circumferential segments however exhibited highly stronger biomechanical resistance than sample III, which was stamped longitudinally. In samples I and II there was a negative correlation between thickness of the wall and ultimate tensile stress (N/mm2). Freezing of the material prior to test at -18degrees C for one week resulted in a significant rise in ultimate tensile strength and stress. The meaning of these findings for comparative angiology is discussed.

Age Factors↗
PubMed1976

[Mineral contents of the blood and chemical composition of the muscles of trichinella-infected piglets (author's transl)].

Three piglets of 22 kg were infected each with 10 larvae of Trichinella spiralis per g body weight. In the blood plasma the contents of several electrolytes were measured twice per week to day 45 post infection (p.i.). These electrolytes, water, dry matter, lipids, nitrogen and ash contents were assayed on samples of muscles of each animal after they were sacrificed on day 61 p.i. Three noninfected piglets served as controls. In blood plasma the contents of Na, Mg, Ca, Cu, Zn and chloride decreased, K- and Fe-contents increased. This process started at earliest on day 7 p.i. Only the Na- and the Fe-contents returned partially to preinfection values up to the end of the investigation period. In the muscles the Ca-contents were increased strongly on day 61 p.i., the Cu- and Zn-contents not the the same extent. There was a decrease in Fe, P, K, Na and Mg contents. The water contents of the muscles increased from 0.53 to 4.9%. The portion of dry matter was reduced correspondingly. Lipids contents increased 2.0 and 127.9% and ash contents 1.7 to 4.4%. Nitrogen contents were reduced by 2.5 to 5.9%.

Animals↗