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Biomedical subjects

A Mandich

Publications and source records attributed to A Mandich.

12 recordsLinked to original sources
PubMed1994

Presence of angiotensin II immunoreactivity in the ovary of the rainbow trout, Oncorhynchus mykiss.

Renin-angiotensin system is present in mammalian ovarian follicular fluid and follicles. The demonstration of specific binding sites for angiotensin II in the follicular structures of rats suggests that angiotensin II may be related to the regulation of steroid biosynthesis in the mammalian ovary. Little is known about the presence and the action of angiotensin II in nonmammalian ovaries. An immunocytochemical investigation of angiotensin II in developing ovarian follicles of trout has been carried out. The specific antiserum was raised against (Val5)-angiotensin II of the trout. There was strong immunoreactivity in the ooplasm of endogenous vitellogenic follicles. Angiotensin II immunoreactive material was present in the follicular cells, but not within oocytes at the end of vitellogenesis. Immunocytochemically angiotensin II-like material in the ovary of rainbow trout fluctuates during the cycle of development.

Angiotensin II↗
PubMed1991

Atrial natriuretic peptide in trout ovarian follicles.

An immunocytochemical study on atrial natriuretic peptide (ANP) was carried out in trout ovaries using an antiserum raised against human atrial natriuretic peptide (hANP). Weakly immunoreactive material was observed both in the ooplasm of the previtellogenic and the early vitellogenic oocytes and in the follicular cells of the late vitellogenic oocytes. Binding sites for hANP have been located using 125I-ANP and light-microscopic autoradiography. These studies provide evidence of specific binding of ANP-like material in both early and advanced vitellogenic oocytes. Autoradiograms indicated that the ANP-like binding sites were localized to a subpopulation of follicles. The presence of ANP-like immunoreactive material and its specific binding sites in the ovary suggest a role for atrial natriuretic peptide as a regulator of the fish ovarian function.

Animals↗
PubMed1989

Intrarenal localization of angiotensin II specific binding in rat fetuses.

Specific binding sites for angiotensin II were localized in the developing rat kidney (18th day of pregnancy and immediately before birth) by autoradiography using [125I]-ileu-5-angiotensin II either perfused in vivo through the fetal aorta or added in vitro to frozen sections in an incubation mixture. Specific binding was localized in the walls of the afferent and efferent arterioles, in the intraglomerular cells and in the peritubular arterioles of the subcapsular cortical zone. The immunohistochemical analysis, carried out on receptors saturated with unlabelled angiotensin II perfused through the mother's aorta, confirmed the autoradiographical localization. Antisera against ileu-5-angiotensin II were used in the indirect immunofluorescence technique and in the PAP method. Immunolocalization of angiotensin II was also found in the proximal tubule and in the thick ascending limb of Henle's loop.

Animals↗
PubMed1988

Angiotensin II specific receptors in subcommissural organ.

In the subcommissural organ of male rats, a circumventricular organ situated inside the blood-brain barrier, specific receptors for angiotensin II were demonstrated by binding studies on homogenated membranes and by autoradiography carried out on frozen sections using 125I-angiotensin II. The receptor sites were localized in the subnuclear region of cells of the subcommissural organ. A single class of binding sites was found whose capacity was modulated by changes in the sodium plasma concentration which led to variations in plasma volume.

Angiotensin II↗
PubMed1988

Angiotensin II vascular receptors in fetal and neonatal rats.

Specific binding sites for angiotensin II in aorta and renal arteries have been studied in rat fetuses (18th day of pregnancy) and 1-day-old newborn rats by binding studies in arterial membranes using [125I] ileu-5-angiotensin II. One type of angiotensin receptor was found both in fetuses and in the newborns; the capacity of this (RT) decreased immediately after birth (from 0.06 +/- 0.01 nM to 0.02 +/- 0.005 nM; +/- SEM) and the affinity (Kd) increased at birth (from 3.5 +/- 0.6 nM to 19.5 +/- 1.2 nM; +/- SEM). Localization of the specific binding sites was studied by autoradiography on arteries from fetal and newborn rats either perfused with iodinated angiotensin II by cannulation of the aorta or in vitro on cryostat sections incubated with the radioactive angiotensin II. Both in fetuses and in the newborn the binding sites were located in the tunica media of the arteries.

Aging↗
PubMed1987

Osmotic stress, plasma renin activity, and spermatogenesis in Vipera aspis.

Circulating electrolytes (Na+, K+), plasma renin-like activity, testosterone, and testis morphology were investigated in early summer during the spermatogenic progressive phase in Vipera aspis subjected to sodium loading and sodium depletion. After sodium loading, plasma sodium and plasma testosterone levels were significantly elevated compared with those of controls, while plasma renin-like activity was depressed, spermiogenesis was increased, the epithelium lining the epididymis was very thick, and the Leydig cells were hypertrophied. After sodium depletion, plasma sodium and plasma testosterone levels were significantly depressed and plasma renin-like activity was significantly elevated. Spermiogenesis seemed to be slightly regressed: the epithelium lining the epididymis was very thin, and the lumen was devoid of spermatozoa. The Leydig cells were hardly visible. All the data strongly suggest that osmotic stress affects gonadal activity in the snake. V. aspis.

Animals↗
PubMed1983

The site of 7-dehydrocholesterol ultraviolet photolysis in domestic fowls.

The site of the photolytic reaction leading to Vitamin D3 in fowls integument has been investigated by histochemical and biochemical analysis. The Vitamin D3 precursor, 7-dehydrocholesterol, is synthetized and stored mainly in the uropygial gland and in the same localization several amount of Vitamin D3 may be biochemically detected. 7-dehydrocholesterol and Vitamin D3 are also present although in a lesser amount in the unfeathered skin of the legs. Photolytic conversion of the Vitamin D3 precursor of uropygial origin may occur also on the dorsal feathers.

Animals↗
PubMed1979

beta-Glucuronidase activity in the developing uropygial gland.

The presence of sterolic compounds and beta-glucuronidase activity have been studied in the uropygial glands of chick embryos (18th day of inc.), chickens (3 weeks after hatching) and young fowls (5 months old). Sterols are histochemically detectable only after hatching and beta-glucuronidase activity, very faint before hatching, reaches its maximum in chicken glands with a peculiar inner localization coincident with sterolic localization. It is suggested that beta-glucuronidase has in uropygial gland a double functional significance: a certain amount of activity is developed to cell proliferation whereas a more strong activity is involved in the hydrolysis of sterol glucuronides.

Animals↗
PubMed1978

Occurrence of 7-dehydrocholesterol in the uropygial gland of domestic fowls.

Histochemical studies on the uropygial gland of domestic fowls have shown the presence of sterols (among which cholesterol and its esters) in the lipidic fraction of the gland secret. beta-Glucuronidase activity beside A5 3beta- and 17beta-hydroxysteroid dehydrogenase activities suggests that uropygial gland might be involved in sterols metabolism. By thin layer chromatography cholesterol and 7-dehydrocholesterol can be separated from the uropygial extracts and these compounds can be identified in gas liquid chromatography.

17-Hydroxysteroid Dehydrogenases↗
PubMedDate not supplied

Dynamic performance analysis: a framework for understanding occupational performance.

Occupational therapy is now consistently described as a profession concerned with enabling occupation. A crucial step in enabling occupation is understanding the occupational performance of our clients. Dynamic Performance Analysis (DPA) is a new approach to occupational analysis that focuses on the client's actual performance. DPA, acknowledging that optimal performance is the product of the interaction of person, environment, and occupation, and thus highly individualistic, places the client and his or her occupation, in interaction with the environment, at the center of the analysis process. Embedded in a top-down framework, DPA is a dynamic, iterative process, carried out as the client performs the occupation. The purpose of DPA is to identify where performance breaks down and test out solutions. In this article, the rationale, origins, and basic assumptions of DPA are discussed, and a detailed description of the DPA process together with two clinical examples is presented.

Cognition↗