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Biomedical subjects

P A Vunder

Publications and source records attributed to P A Vunder.

At least 19 recordsLinked to original sources
PubMed1985

[Differences in the rate of establishment of permanent estrus in rats after autotransplantation of the ovaries and as affected by other conditions].

In adult female rats, constant light leads to the cessation of the sexual cycle and formation of permanent estrus after 6 to 7 days. In young animals, the sexual cycle was retained despite constant light and only after 3 months when the body weight of the rats reached 200-220 g the estrus became permanent. This happened earlier than in animals with the ovaries autotransplanted to the ears. The combination of constant light and autotransplantation of the ovaries caused an earlier formation of permanent estrus. It is marked that the same mechanism (the age-associated decrease of the cyclic center sensitivity to estrogen) underlies permanent estrus of various etiology.

Aging↗
PubMed1984

[Early changes in the permeability of cellular and lysosomal membrane in rat testes after local heating of the scrotum].

Immersion of rat scrotum into water (41 degrees C) for 30 min leads to gross impairment of spermatogenesis. During incubation in Ringer-Krebs solution at 33 degrees C for 1h, fragments of the decapsulated testes taken from the heated rats secrete to the medium a high amount of substances that increase the optical density of the incubation liquid at 270 nm. This phenomenon can be recorded shortly after scrotum heating is completed. The optical density increases further 12 and 24 h after heating. During incubation, fragments of the testes heated in vivo also secrete a high amount of the lysosomal enzymes, acid phosphatase and cathepsin D. It is assumed that post-thermal degeneration of the spermatogenic epithelium may be determined by a change in the permeability of cellular and lysosomal membranes.

Animals↗
PubMed1984

[Reaction of the ovary of the young rat to transplantation into the spleen of adult castrated diabetic animals].

The ovary of an infantile rat was grafted into the spleen of adult castrated females. After 7-9 days half of the animals were injected with alloxan subcutaneously. The rats were decapitated 33 days after ovary grafting. In all diabetic rats and 62% of the control animals, the vaginal smears showed persistent diestrus. The height of the uterine epithelium was fairly low. Persistent estrus was detected in 38% of the control animals. In the diabetic group, the degree of ovarian hypertrophy was significantly lower than in the control group, although no differences were discovered in pituitary gonadotropin content in both the groups. It is suggested that the pituitary of diabetic animals slightly responds to estrogenic deficiency. This was manifested in a lesser degree of ovarian hypertrophy and in the absence in the ovaries of the majority of diabetic rats of the phenomena such as the proliferation of the connective tissue and the appearance of granulocellular tissue accumulations.

Aging↗
PubMed1983

[Mechanism of the development of permanent estrus in rats after transplantation of the ovaries into a low temperature medium].

Autotransplantation of the ovaries to the ears of adult rats induces permanent estrus following 5-7 days. Autotransplantation of the ovaries beneath the renal capsules makes the sexual cycle return to normal after the same period. Autotransplantation of the ovaries to the ears of infantile rats brings about pubertas precox followed by normal sexual cycle. Permanent estrus ensues only after 4 months. Transplantation of the ovaries from infantile rats to adult ones and vice versa has shown that age-related differences in the alterations seen in the sexual cycle in response to gonadal transplantation to the ears are caused by age-related differences in the recipients, precisely by those in the cyclic center.

Age Factors↗
PubMed1980

[Compensatory ovarian hypertrophy during alloxan diabetes and adrenoreceptor blockade].

The sexual cycle ceases in rats with alloxan diabetes. Chronic administration of phentolamine promoted interruption of the sexual cycle while obsidan was conducive to its preservation in part of the animals. Most diabetic rats both given and not given adrenoblockers showed the complete absence of compensatory hypertrophy of the ovary (CHO). As shown by the analysis, the content of gonadotropins in the pituitary glands of diabetic rats was increased, with the response to chorionic gonadotropin being close to normal. It is suggested that the absence of CHO in most diabetic rats can be accounted for by the fact that after removal of one ovary the hypothalamohypophyseal system does not secrete gonadotropins in adequate amounts.

Alloxan↗
PubMed1976

[Effect of preliminary stress on mitotic activity of the regenerating liver].

Male rats were exposed to 14- or 24-hour immobilization before partial hepatectomy. Some of these animals were given subcutaneous theophylline injections immediately after and the next day after the immobilization. A tendency to increase of the mitotic activity of the regenerating liver was seen in the stress-subjected animals. This effect was particularly pronounced in rats given theophylline.

Animals↗
PubMed1976

[Effect of adrenoreceptor blockaders on the mitotic activity of regenerating liver].

One hour before resection of the liver and repeatedly 24 hours after the operation male rats were given phentholamine--a blocker of alpha-adrenoceptors; this preparation inhibited the mitotic activity of the regenerating liver. A double administration at the same periods of propanol--a blocker of beta-adrenoceptors--caused an elevation of the mitotic activity. A conclusion was drawn that by stimulation of beta-adrenoceptors it was possible to inhibit the regenerative process. Adrenaline stimulated this process by acting through beta-adrenoceptors.

Animals↗
PubMedDate not supplied

[Development of alloxan diabetes and its effect on the sexual system of male rats under conditions of alpha adrenergic receptor blockaders].

A study was made of the influence of the block of the alpha-adrenoreceptors in male rats on the development of alloxan diabetes and on such its complication as depression of the sexual system function. Phetholamine sharply decreased the death of the animals the first 3--4 days after the alloxan administration: only 5.3% of the animals died. As to rats with intact alpha-adrenoreceptors--42% of the died. Block of the alpha-adrenoreceptors decreased the percentage of rats with marked diabetes. In 37.2% of rats given alloxan and phentholamine diabetes was very mild or failed to develop entirely. Phentholamine significantly lowered the depressive effect of alloxan diabetes on the sexual system considerably.

Animals↗