Biomedical subjects

N Mihić

Publications and source records attributed to N Mihić.

14 recordsLinked to original sources

PubMed1993

[Characteristics of the human lateral geniculate nucleus vascular network].

The blood supply of the lateral geniculate nucleus (LGN) was studied on ten human brains obtained at autopsy from patients of both sexes with no indication of either psychiatric and neurological disorders or trauma of CNS. The age range was form 30 to 50 years. The brain blood vessels-the basilar artery and the internal carotid artery were injected with a mixture of gelatin and Indian ink. Microdissection revealed that the arterial branches for the LGN arise from anterior choroidal artery and posterior cerebral artery through one of its central branches-lateral posterior choroidal artery. The morphology of arterial network was examined by the analysis of cleared paraffine sections. The arterial branches run in a dorsal to ventral direction of the nucleus, parallely with lines of projection and perpendicularly to the plane of the LGN laminae. Free anastomoses occur between these branches.

Adult↗

PubMed1993

[Vascular characteristics of the lamina terminalis of the human hypothalamus].

The aim of the study is to discover the sources of vascularization, vascular area, the size and density of the capillary network of the vascular organ of the laminae terminalis of the hypothalamus. The brain blood vessels under examination were filled with a mixture of India ink and gelatin. The serial paraffin sections of 30 and 200 um were cleared after Spalteholz. In the vascularization of this neuroendocrine structure of the hypothalamus, two arterial stems take part with their branches: a cerebri anterior and a. communicans anterior. In order to quantify the density of the capillary network, the authors used standard stereologic parameters - volumene density, surface density and mean radius of blood vessels. While the precise functions of the vascular organ have yet to be fully elucidated, the similarity in organization of this region to the median eminence has led several authors to suggest a neurosecretory role for the vascular organ of the lamina terminalis.

Blood Vessels↗

PubMed1992

[The effect of chronic alcohol administration on specific features of the adenohypophysis in young animals in relation to the adult adenohypophysis].

We investigated chronic effects of ethyl alcohol on adenohypophysis in adult Wistar rats and adenohypophysis in development including the postnatal period up to 30 days. Morphological findings in gonadotropic, prolactin and follicular cells were compared. After three months of constant alcohol consumption in the form of a 15% liquid solution, vacuolization of gonadotropic cells which acquire the shape of a seal ring, as well as nodular hyperplasia of chromophobe cells combined with sparse somatotropic cells, occur in the adenohypophysis of adult male rats. Electronic microscope revealed a small quantity of prolactin granules in light-microscopic chromophobe cells. In young rats exposed to alcohol gonadotropic and prolactin cells are unchanged but an accumulation of follicular cells within multiple smaller pseudofollicles is present. In the explanation of the differences between the findings obtained in adult and young rats with reference to LH/FSH and PRL cells, a stress is given to the role of the peripheral metabolism of testosterone and of hyperestrogenemia caused by alcohol consumption in adult rats lacking in young ones. The increased number of the follicular cells in adenohypophyses of young rats is likely to reflect the suppressed maturation of hypophyseal secretory cells.

Aging↗

PubMed1991

[Characteristics of the vascular network in the hypothalamic median eminence in man].

The aim of these studies is to determine the sources of vascularization, the vascular areas, the appearance and density of the median eminence capillary network in prenatal human brains of both sexes. The brain blood vessels under examination were filled with a mixture of India ink and gelatin. Serial paraffin sections 20-40 microns thick, cleared after Spaltehol. Two arterial stems take part in median eminence vascularization together with their branches: a. hypophisialis superior and a. hypophisialis inferior. In order to quantify the density of the capillary network, the authors used the standard stereologic parameters--volume density and mean radius of blood vessels. No statistically significant sex-dependent differences were established regarding the appearance and density of the median eminence capillary network of the human brain in the course of the comparative testing of the mean values of these parameters in the male and female sex.

Blood Vessels↗

PubMed1990

[Morphometric analysis of the vascular network of the suprachiasmatic and paraventricular nucleus in the human brain].

The aim of the study is to discover, the sources of vascularization, vascular areas, the size and density of the capillary network in the suprachiasmatic and the paraventricular nuclei of postnatal human brains of both sexes. The brain blood vessels under examination were filled with a mixture of India ink and gelatin. The serial paraffin sections of 200 microns cleared after Spalteholz. In the vascularization of the suprachiasmatic and the paraventricular nuclei, two arterial stems, take part with their branches (a. cerebri anterior and a. communicans anterior). In order to quantify the density of the capillary network, the authors used the standard stereologic parameters - volume density, surface density and mean radius of blood vessels. The comparative testing of the mean values obtained in male and female subjects did not reveal any significant sex - dependent differences regarding the size and density of the capillary network in the suprachiasmatic and the paraventricular nuclei of the human brain.

Capillaries↗

PubMed1989

[Morphometric analysis of the vascular network in the preoptic area of the brain in man].

Twenty brains of human beings of both sex aged 17-64 were used for morphometric analysis of the vascular network of preoptic area. Blood vessels of the brain were filled by the mixture od India ink and gelatine. Serial resections 200 microns thick were illuminated by the method of Spalteholz. Standard stereologic parameters--volume density, surface density and the average half diameter of blood vessels were used for the quantification of capillary blood network density. By the comparative test of obtained mean values of males and females no statistically significant differences pertaining to sex and in respect to the size and density of capillary network in preoptic area were confirmed. This fact supported the assumption that although there were no morphologic differences in the blood network changes in various functional states, accompanying neuroendocrine events in the body of adults were in all probability the main and responsible factors inducing greater or less vascularization of specific organs.

Adolescent↗

PubMed1989

[Membranous lesions and histochemical changes in cardiac muscle cells during hypoxia in white rats].

The authors of this paper have explored the effects of intermittent hypoxia on the cell membrane and histochemical changes in the muscle cardiac tissue of the white rat. The animals have been exposed to the experimental conditions characteristic of 7.000 m of height above sea level and divided in three groups. The first one consisted of animals sacrificed immediately after the final exposition (first experimental group), in the second one there were animals sacrificed 24 hours after (the second experimental group), and the third group made animals sacrificed 7 days after the final exposition (the third experimental group). The hypoxial stress elicited the vacuolation in the cardiac muscle fibers of the subendocardial layer of miocard which persisted, and did not reduce its intensity and extensity in all the three groups of animals, while in fuxinorrhagia the intensity and extensity falls to the half of the animals sacrificed 24 hours after the experiment, and completely disappeared in those sacrificed 7 days after the final exposure. Glycogen as well as the activity of succinat-dehydrogenase were preserved in all the three experimental groups of animals. It could be concluded that hypoxia elicites ischemical changes in the sense of vacuolation of muscle tissue which does not disappear or its disappearance is slower than is the case with fuxinorrhagia which leaves a clear evidence, too, that the permeability of cytoplasmatic membrane affected by hypoxia was disturbed.

Animals↗

PubMed1989

[Stereologic analysis of the density of the vascular network of the heart in hypoxia in laboratory rats].

The density of the myocardiac vascular network in 3-month-old female Wistar rats exposed to intermittent hypoxia was studied. The experimental rats were sacrificed immediately (1st experimental subgroup) or 4 days (2nd experimental subgroup) after the last exposition. The volume density was statistically highly significant in the animals of the 1st subgroup and significant in the rats of the 2nd subgroup. The highly significant rise in the volume density of the myocardiac vascular network could be explained by an acute stress effect, whereas the only significant increase in the second case indicates adaptability to stress.

Adaptation, Physiological↗

PubMed1988