Biomedical subjects

D E Korzhevskiĭ

Publications and source records attributed to D E Korzhevskiĭ.

At least 19 recordsLinked to original sources

PubMed2006

[Organization and cytochemical features of barrier structures in human placenta].

The aim of the present study was to investigate structural pattern of human placental barrier elements using light and electron microscopy and immunocytochemistry. Some important peculiarities of organization of the placental barrier were detected: difference in structure and amount of collagen IV in the basal lamina of endothelium and trophoblast, occurrence of smooth muscle actin in the capillary wall forming syncytiocapillary membranes. In the intercapillary stroma of terminal villi, both fibroblasts and macrophages but not myofibroblasts were found. Since smooth muscle cells and myofibroblasts are absent, pericytes are most likely cells to contain smooth muscle actin in the area of syncytiocapillary membranes.

Actins↗

PubMed2006

[Use of zinc-containing dehydrating fixatives for neurohistological studies].

The suitability of zinc-containing dehydrating fixatives for neurohistological study of paraffin sections using Nissl staining and immunocytochemical techniques was examined. It was found that zinc-containing dehydrating fixatives (zinc-ethanol-formaldehyde and zinc-acetone-isopropanol-formaldehyde) had a capacity for good preservation of both structure and antigenic properties of the nervous tissue and could be recommended for application in neurohistological studies.

2-Propanol↗

PubMed2005

[Suppression of glial fibrillary acidic protein expression in astrocytes of the superficial glial limiting membrane after traumatic subarachnoid hemorrhage].

Although typical astrocytic reaction to brain injury is accompanied by an increase of glial fibrillary acidic protein (GFAP) expression, to what degree this reaction is universal remains to be elucidated. The aim of the present study was to investigate the reaction of superficial glial limiting membrane of human brain to traumatic subarachnoid hemorrhage. Using light microscopy and immunocytochemistry, it was found that a suppresion of GFAP expression in astrocytes of superficial glial limiting membrane occurred up to 3 days following the brain trauma. The data obtained suggest the existence of regional peculiarities of astrocytic reaction.

Adolescent↗

PubMed2005

[Immunocytochemical demonstration of catecholaminergic structures in paraffin sections of the rat brain using various methods of fixation].

The study was undertaken to investigate the effect of various methods of fixation of the brain upon the demonstrability of catecholaminergic structures using tyrosine hydroxylase (TH) immunocytochemical reaction. It was established that most complete demonstration of TH-containing structures was achieved after perfusion fixation with 4% paraformaldehyde followed by post-fixation in the Carnois fluid and after immersion fixation in the IHC zinc fixative (BD Pharmingen, U.S.A.). Immersion fixation in 4% paraformaldehyde, ethanol-formaldehyde, Carnois and Bouin fixatives can be used for demonstration of perikarya of catecholaminergic neurons.

Animals↗

PubMed2005

[Application of methods of heat retrieval of antigens in paraffin sections of rat brain].

The aim of this study was to develop an optimal protocol of processing of rat brain sections permitting to minimize the shortcomings of the method of heat retrieval of antigens and preserving its high efficiency. The research was conducted using the methods of heat antigen retrieval, immunohistochemistry and light microscopy. It was shown that prolonged incubation in blocking solution, containing normal serum of an animal--source of secondary antibodies, eliminated false-positive reaction, demonstrated after heat antigen retrieval in paraffin sections of rat brain.

Animals↗

PubMed2005

[Modification of histogenetic processes in rat nervous tissue after dexamethasone administration during prenatal development].

In experiments performed on rats, using the methods of confocal microscopy and immunohistochemistry, it was detected that administration of a single dose of synthetic corticosteroid dexamethasone during the period of increased sensitivity of developing nervous system (embryonic day 13) resulted in modification of histogenetic processes in the brain, resulting in the changes of its structural and functional characteristics during postnatal period of ontogenesis.

Animals↗

PubMed2005

[Immunocytochemical demonstration of brain neurons using NeuN as a selective marker].

The aim of the present study was to find optimal protocol of immunocytochemical reaction to NeuN nuclear protein for light and laser confocal microscopy, which would exclude the antigen heat unmasking procedure that results in deteriorating the state of the tissue and requires expensive adhesive-coated slides. Best preservation of the antigen was found to be provided by fixation in zinc-formalin and Bouin's fixative (for a period of less than 24 hrs). Two protocols allowing to avoid antigen heat unmasking procedure during demonstration of the NeuN neuronal label in paraffin sections by the light and confocal microscopy are presented.

Animals↗

PubMed2005

[Structural organization of macrophages in forming human placenta].

Placental macrophages (Kashchenko-Hofbauer cells) belong to a special population of tissue macrophages of human fetal provisional organs. The aim of the present study was to investigate the structure of Kashchenko-Hofbauer cells at the stage of placenta formation using the methods of light and electron microscopy and immunocytochemistry. Cytological and cytochemical peculiarities of Kashchenko-Hofbauer cells revealed in this study, leave no doubt that they belong to the tissue macrophages group. Their cytoplasm is strongly reactive with antibodies against CD68 lysosomal antigen suggesting potentially high phagocytic activity of these cells. Weak nuclear labeling with proliferation marker PCNA was found in placental macrophages.

Antigens, CD↗

PubMed2004

[Ischemic adaptation of the rat brain as a method for protection of endothelium from ischemic reperfusion injury].

This study represents results of investigation carried out to determine the endothelium-protective effect of early and late phases of brain ischemic preconditioning as well as local and remote adaptation. The experiments were performed on adult male rats. Prolonged 30-min four vessels brain ischemia followed by 120-min reperfusion on carotid arteries, was performed (control group). Early and late local ischemic preconditioning was due to both 5-min ischemia and 30-min and 48 h reperfusion respectively on carotid arteries. Remote ischemic preconditioning was caused by 30-min ischemia and also by 15-min and 48 h reperfusion, respectively (early and late phases of adaptation) on femoral artery before prolonged brain ischemia described above. To estimate the role of nitric oxide in ischemic adaptation, mechanisms involved both nonselective blocker of NO-synthesis (N omega-nitro-L-arginine) in the time of early adaptation phase and the relatively selective iNOS inhibitor S-methylisothiourea sulfate, given before sustained brain ischemia, on the late preconditioning. Registration of brain blood flow was made by ultrasonic high-frequency Doppler device. Degree of brain edema was studied and evaluation of desquamated endothelial cells in blood was carried out. Early and late phases of local ischemic preconditioning were found to improve the brain blood flow and level of circulatory endothelial cells as well as to reduce degree of edema. The endothelium-protective effect of remote ischemic preconditioning has been proved in this study only on the late phase. Nitric oxygen was found to be important endothelium-protective factor in ischemic preconditioning.

Adaptation, Physiological↗

PubMed2004

[Structural characteristics of astrocytes from the rat hippocampus in postischemia].

The aim of this investigation was to study the distribution and structural organization of rat hippocampal astrocytes containing immunoreactive glial fibrillary acidic protein (GFAP) after ischemic damage of the brain in the animals treated with intraventricular infusion of creatine as a neuroprotective drug, and in those which received no treatment. Using the methods of light microscopy and immunocytochemistry, the brain of 26 mature Sprague-Dawley (Koltushi) rats was studied. Some animals were narcotized and subjected to general brain ischemia (lasting for 12 min) followed by a reperfusion (for 7 days). Creatine was infused intraventricularly to 11 animals using an automatic Alzet osmotic minipump. It was found that GFAP-immunoreactive hippocampal astrocytes were concentrated within two major areas (stratum lacunosum-moleculare CA1 and fascia dentata stratum polymorphae). As a result of neuroprotective effect of creatine, moderate ischemic damage of the hippocampus was not followed by the changes in the zones of activated astrocyte localization. Redistribution of GFAP-positive astrocytes in postischemic period was caused by the loss of pyramidal neurons in cytoarchitectonic field CA1. Complete loss of pyramidal neurons in this hippocampal area resulted in a qualitatively new level of astrocyte activation--their proliferation.

Animals↗

PubMed2004

[Immunocytochemical demonstration of astrocytes in brain sections combined with Nissl staining].

The aim of the present study was to develop an easy and reliable protocol of combined preparation staining, which would unite the advantages of immunocytochemical demonstration of astrocytes with the availability to evaluate functional state of neurons provided by Nissl technique. The presented protocol of paraffin sections processing allows to retain high quality of tissue structure and provides for selective demonstration of astrocytes using the monoclonal antibodies against glial fibrillary acidic protein and contrast Nissl staining of cells. The protocol can be used without any changes for processing of brain sections obtained from the humans and other mammals with the exception of mice and rabbits.

Animals↗

PubMed2004

[Glial fibrillary acidic protein in astrocytes of the human neocortex].

Glial fibrillary acidic protein (GFAP) is a brain astrocyte-expressed protein that is recognized as one of the main immunohistochemical markers of these cells. The aim of the present study was to investigate the structure of GFAP-positive astrocytes of human neocortex. Main types of GFAP-immunoreactive astrocytes in the human neocortex were characterized using immunohistochemistry and confocal laser microscopy. These are astrocytes of the layer I forming the surface border glial membrane, translaminar astrocytes of the layer I with very long processes penetrating several cortical layers, astrocytes of middle layers of the neocortex with a general organization of protoplasmic-type astrocytes which are involved in formation of perivascular border membrane, and typical fibrous astrocytes of the white matter. The data obtained will contribute to unification of evaluation of histopathologic processes observed in various kinds of gliosis in the CNS.

Adolescent↗

PubMed2003

[Morphological and cytochemical properties of the human glioblastoma T98G cells during the monolayer culture].

The study was carried out with the aim of determination of morphological and cytochemical properties of human glioblastoma T98G cells in monolayer culture. Using light microscopic and immunocytochemical techniques, the glioblastoma cell line studied was shown to have low susceptibility to the effects of environmental factors and changes in culture conditions as well as high proliferative activity. All T98G cells were demonstrated to have positive nuclear reaction for p53 protein. An ability of T98G cells for spontaneous caspase 3-mediated apoptosis was shown using the antibodies against activated caspase 3. The data obtained suggest that glioblastoma T98G cell line could be used as a convenient model for testing the capacity of natural substances and of pharmaceutical agents that are being developed for the selective induction of caspase 3-mediated apoptosis.

Apoptosis↗

PubMed2003

[Modification of Carazzi alum hematoxylin compounding].

This investigation was aimed at the improvement of the compounding of alum hematoxylin. The advantages and disadvantages of the prevalent versions of Carazzi alum hematoxylin compoundings are analyzed. A novel modification of the Carazzi hematoxylin compounding is proposed, which is optimal for hematoxylin and eosin staining and for counterstaining of immunocytochemical preparations.

Coloring Agents↗

PubMed2003

[Preparation of Harris hematoxylin without use of mercury oxide].

The study was carried out with the aim of improvement of Harris' alum hematoxylin formula. In presented modified formula toxic mercuric oxide (2.5 g) is substituted by potassium iodate (0.55 g). Alum hematoxylin solution prepared according to suggested formula retains high quality of original Harris' hematoxylin.

Glycerol↗

PubMed2002

[Structural organization of choroid plexus primordium in human telencephalon].

Using the methods of light and electron microscopy and immunocytochemistry, the structure of choroid plexus primordium of telencephalon (epithelial plate) was studied in human embryos at weeks 5-6 of development. It was established that at this stage human choroid plexus primordium is an area of active morphogenesis. Rapid changes in its configuration in the course of choroid plexus formation are preceded by a suppression of proliferation and an activation of degenerative processes. Ultrastructural organization of choroid plexus primordium and specific structural features of its cells indicate that the tissue, forming the epithelial plate, substantially differs from the neuroepithelium that forms the primordia of hippocampus and neocortex, already at this very early stage of prenatal ontogenesis. Accumulation of p53 and bcl-2, proteins participating in apoptosis control, is the evidence of a special functional state of this morphogenetic zone, the detailed characteristic of which requires further research applying a wider spectrum of functional markers.

Cell Differentiation↗

PubMed2002

[Bcl-2 protein expression in developing human brain].

Using immunocytochemical methods, the expression of bcl-2 antiapoptotic protein was studied in developing brain of human 5-8-week embryos. It was established that during the period studied several zones of bcl-2-positive cell concentration were present. These included the ventricular zone of the brain vesicles wall, cortical plate, medullary nuclei, vascular plexus primordium (in 5-6-week embryos), IV ventricle roof and vascular plexus of rhombencephalon. In the area of forming leptomeninx, bcl-2 protein was demonstrated in the endothelium of blood vessels. The detection of intensified expression of bcl-2 protein in some cellular populations of developing human brain proves their increased stability against apoptosis and indicates their priority significance in the provision of normal neurohistogenesis.

Brain↗

PubMed2002

[Damaging impacts at the critical time periods of prenatal ontogenesis as a factor modifying the cerebral structural development and postnatal behavior reactions].

Results of a study of the nature of changes in the rat neocortex, which were observed during an early postnatal period (postnatal days 1 to 10) and which were induced by a single prenatal hypoxia on the 16th or 19th embrionic day (E16, E19), are presented in the paper. Acute hypoxia, administered on E16, was shown to result in an underdevelopment of cortical layers as well in damage to cell orientation and differentiation, i.e. it disturbed the histogenic processes (proliferation, migration and differentiation), which are most active at this time period. An immunohistochemical examination of the brain made during the postnatal period after an intrauterine hypoxia suggests that damage to proliferation and differentiation occurred in glial cells. Hypoxia administered on E19, when the level of proliferation in the brain was lower, had a less pronounced damaging effect. Deviations in the neocortical structure and in the animal's behavior found during the postnatal period could be caused by the heterochromic and heteromorphous development of brain regions in the fetus.

Animals↗