-
[show abstract]
[hide abstract]
ABSTRACT: The aim of the study was the evaluation of ultrastructural changes in rats central and peripheral nervous system after the introduction of experimental allergic encephalomyelitis (EAE) and after the treatment with spinal cord protein hydrolysate. Reduced structural disturbances in myelin were found after oral treatment with hydrolysate. In addition, the indications of remyelinization processes have been observed.
Folia neuropathologica / Association of Polish Neuropathologists and Medical Research Centre, Polish Academy of Sciences 02/1998; 36(4):244-8. · 1.23 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Here, using a histochemical staining for a microglia/phagocyte marker TPP-ase (Murabe, Sano 1981), and an electron microscopy we characterized the population of pituitary phagocytic cells activated by cerebral ischemia. An intense thiamine pyrophosphatase (TPP-ase) activity was demonstrated in glial cells and some cells of blood vessels of neural lobe, late period (12 months) after experimental ischemia. TPP-ase positive cells were ultrastructurally identified as pituicytes, microglia, pericytes and perivascular cells. The product characteristic for TPP-ase activity was seen on plasma membrane of these cells. Our electron-microscopic histochemical results provide strong support for a role of pituicytes, pericytes and perivascular cells as a phagocytic cells involved in mechanism of elimination of ischemically damaged axonal endings in neural lobe.
Folia neuropathologica / Association of Polish Neuropathologists and Medical Research Centre, Polish Academy of Sciences 02/1998; 36(2):109-16. · 1.23 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Dotarizine--the novel piperazine derivative--belongs to wide spectrum Ca2+ channel antagonists. It was reported to have strong vasodilatatory and antiserotoninergic activities. Comparing with other Ca2+ channel blockers Dotarizine was found to have lower oral toxicity. In the present study the influence of the oral administration of the novel compound on the blood flow velocity changes in different cerebral arteries--in basilar artery (BA) and middle cerebral artery (MCA)--was investigated under hypoxic conditions. The ultrastructural morphological changes of intracerebral vessels endothelium in treated and untreated anoxic animal groups were also demonstrated. The experiments were carried out on rabbits. In the experimental group 25 mg/kg of Dotarizine dissolved in 0.25% agar was administered orally three times at the 10 hours' intervals. The sham group of animals was fed with agar of the same concentration. During anoxic conditions strong vasodilatory effects were observed in both investigated vessels of drug-treated animals. In the experimental group marked ultrastructural differences in parenchymal vessel endotheliumin comparison to sham group were revealed. Thus, the oral administration of Dotarizine might have effect on the various parts of the cerebrovascular system and can play significant role in improvement of various cerebrovascular disorders.
Folia neuropathologica / Association of Polish Neuropathologists and Medical Research Centre, Polish Academy of Sciences 02/1998; 36(2):101-8. · 1.23 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Brain phagocytes are members of a heterogeneous family of microglial cells. In this study we investigated the membrane activity of the enzyme, thiamine pyrophosphatase (TPP-ase), in brain phagocytes. Studies were performed on rats subjected to a transient ischemia because ischemic incident precipitates proliferation of microglial cells in the brain. Brain tissue was sampled from animals that survived 12 months after experimentally evoked cardiac arrest. The product characteristic for TPP-ase activity was present in the Golgi cisterns of neurons, basement membranes of endothelia and capillary pericytes. TPP-ase activity was present on plasma membranes of brain phagocytes. The phagocyte TPP-ase activity did not depend on the anatomical localization of the cell in the brain (cortex, hippocampus, hypothalamus). Thus, TPP-ase activity can be considered as a marker of brain phagocytes.
Journal für Hirnforschung 02/1998; 39(2):183-91.
-
[show abstract]
[hide abstract]
ABSTRACT: In this study we investigated the ultrastructural changes in rat myocardium induced by the concomitant treatment of animals with ethanol and the calcium channel antagonist, verapamil. The animals were given perorally either placebo or 8 g/kg body weight ethanol in combination with 3 mg/kg verapamil for 30 days. Rats treated with ethanol and verapamil had ultrastructural myocardiocyte damage. The ultrastructural changes were present in myofibrils, mitochondria, intercalated discs and plasmalemma. Due to widespread use of verapamil for treatment of a variety of cardiological disorders and, therefore, a high risk of its interaction with ethanol the data can be of potential significance for humans.
Experimental and Toxicologic Pathology 01/1998; 49(6):493-6. · 2.78 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Signaling via intercellular junctions plays an important role in the regulation of growth and differentiation of epithelial cells. Loss of cell-cell contacts has been implicated in carcinogenesis, tumor progression, and metastasis. Here, we investigated whether 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] was able to stimulate the assembly of adherens junctions and/or desmosomes in cultured human keratinocytes. After 4-day incubation, 1,25-(OH)2D3 caused assembly of adherens junctions, but not desmosomes. The adherens junctions were identified upon known ultrastructural criteria and evidence of the translocation of specific junctional proteins (E-cadherin, P-cadherin, alpha-catenin, and vinculin) to the cell-cell borders. The presence of alpha-catenin and vinculin at cell-cell borders indicated that the adherens junctions were functional. This was further supported by showing that anti E-cadherin antibody inhibited the 1,25-(OH)2D3-induced keratinocyte stratification. A relation between protein kinase C and adherens junction regulation was noticed. 1,25-(OH)2D3-dependent formation of junctions was blocked by the inhibitors of protein kinase C, bisindolylmaleimide and 1-(5-isoquinolinylsulfonyl)-2-methyl-piperazine (H-7), and treatment of keratinocytes with 1,25-(OH)2D3 caused a rapid activation of protein kinase C and its translocation to the membranes. Formation of intercellular contacts may be an important mechanism of 1,25-(OH)2D3 action in hyperproliferative and neoplastic diseases.
Endocrinology 07/1997; 138(6):2241-8. · 4.46 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In the present study we investigated the effects of brain ischemia on endothelin expression in the hypothalamo-neurohypophysial system of the rat using the post-embedding immunogold technique for electron microscopy. From 24 hours to six months after ischemia, a relatively high endothelin immunoreactivity was observed in some neurosecretory cells of the supraoptic and paraventricular nuclei as well as in endothelial cells of some microvessels of the hypothalamus and neurohypophysis. The results indicate that ischemia is a potent stimulus for increased production of endothelin. The distribution of endothelin-immunoreactive neurons in the hypothalamus was similar to that of vasopressin and oxytocin, so it seems possible that endothelin participates directly in controlling hormonal synthesis and release from vasopressinergic and oxytocinergic neurons in the hypothalamo-neurohypophysial system.
Folia neuropathologica / Association of Polish Neuropathologists and Medical Research Centre, Polish Academy of Sciences 02/1997; 35(2):107-14. · 1.23 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The effect of transient, global cerebral ischemia on the distribution of endothelin (ET) in blood-brain barrier (BBB) in CA1 area of hippocampus long-time after ischemia was estimated using post-embedding immunogold technique. ET-like immunoreactivity as a gold particles was localized in all compartments of the blood-brain barrier e.g. in endothelial cells, in pericytes, in periendothelial space including basement membrane, and in astroglial processes. In control animal the density of labelling in all elements of BBB in CA1 area of hippocampus was moderate. ET-like immunoreactivity (ET-like IR) was estimated 1 week-12 months after ischemia. Intense ET-like IR in all elements of BBB was noted 2 and 6 months after ischemia. A potential pathophysiological role of endothelin in cerebral vasospasm in long-time after ischemia is well documented.
Folia neuropathologica / Association of Polish Neuropathologists and Medical Research Centre, Polish Academy of Sciences 02/1997; 35(1):49-59. · 1.23 Impact Factor
-
B Gajkowska
[show abstract]
[hide abstract]
ABSTRACT: The effect of transient, global ischemia on endothelin (ET) localization in CA1 area of hippocampus of the rats was investigated using post-embedding immunogold method. This paper provides immunocytochemical evidence that cerebral ischemia is accompanied by the increase of production of endothelin in CA1 area of the rat. This study focuses on the analysis ET-like immunoreactive neurons and glial cells in hippocampal CA1 area after long-term survival after ischemia: 1 week-12 months. One and two weeks after ischemia appearance of shrunken neurons and significant increase in ET-like immunoreactivity in astroglial cells as well as their proliferation was observed. Six and twelve months--marked immunoreactivity of endothelin in shrunken neurons and in perineuronal microglial macrophages was observed. The data suggest the possibility that the increased intracellular content of endothelin has a role in the development of neuronal death even following a long-term period after ischemia.
Folia neuropathologica / Association of Polish Neuropathologists and Medical Research Centre, Polish Academy of Sciences 02/1997; 35(1):36-48. · 1.23 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Morphological changes of microvessels of cerebral cortex were evaluated in a model of cerebral infarction initiated by a photochemical reaction. Rats were treated with intravenous injection of rose Bengal and irradiated from a halogen lamp source through an intact cranium to precipitate microvascular damage. Investigations in transmission and scanning electron microscopy revealed platelet aggregation on endothelial cells preceded by its early ultrastructural damage. Other typical microscopic features of brain ischaemic injury were present suggesting that the present method may be used as a model for investigating ischaemic brain damage. Since the photochemical activation of the rose Bengal dye results in formation of reactive oxygen species this model may be particularly useful to elucidate the role of free radical-mediated endothelial damage in the formation of microthrombi and blood-brain-barrier integrity.
Acta neurobiologiae experimentalis 02/1997; 57(3):203-8. · 2.11 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To investigate the influence of squalene on the nervous system, adult male Wistar rats were injected with squalene subcutaneously with 20 g/kg of the body weight for 4 consecutive days. After 7 or 30 days from the initiation of the experiment, brain and ischiadic nerves were harvested for electron microscopy. Squalene affected mostly PNS targeting Schwann cells and myelin sheaths. Accumulation of lipid-like droplets in the myelin sheaths in the PNS and in the neurons in the brain cortex, hypertrophy of endothelium, and sometimes endothelial apoptosis in blood vessels, and increased synthesis of collagen in the ischiadic nerve were characteristic for developed squalene encephaloneuropathy.
Folia neuropathologica / Association of Polish Neuropathologists and Medical Research Centre, Polish Academy of Sciences 02/1997; 35(4):262-4. · 1.23 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Electron microscopy immunocytochemical study was performed to clarify ultrastructural localization and role of endothelial nitric oxide synthase (EC-NOS) in the endothelial cells (EC) of rat hippocampal vessels after transient cerebral ischemia. EC-NOS immunoreactivity was found in the endothelial cells in association with plasma membrane, sub-plasmalemmal vesicles, basal membrane and in cytosol (cytoplasm free of subcellular organelles). A sharp transient increase in immunoreactivity of NOS was observed at 10 min up to 1 hour after ischemia. The results of the present study indicate that NO, as a potent vasodilator, may play a protective role in ischemic brain damage.
Folia neuropathologica / Association of Polish Neuropathologists and Medical Research Centre, Polish Academy of Sciences 02/1997; 35(3):171-80. · 1.23 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Endothelin is a very powerful endogenous vasoconstrictor substance produced by endothelial cells. To examine the potential role of endothelin as a neuropeptide, we studied its distribution in the neurosecretory system. Endothelin-like immunoreactivity (EN-IR) has been demonstrated by an immunogold method in the paraventricular and supraoptic nuclear neurons and their terminals in the posterior pituitary of the rat. ET-IR was enhanced after ischemia suggesting its modulatory role in neurosecretory functions.
Folia neuropathologica / Association of Polish Neuropathologists and Medical Research Centre, Polish Academy of Sciences 02/1996; 34(4):173-7. · 1.23 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Paralytic tremor (pt), a hereditary neurological disorder of rabbits is a recessive, X-linked point mutation of the gene for proteolipid protein (PLP) biosynthesis. This mutation results in substitution of histidine by glutamine in the PLP molecule and produces severe hypomyelination. In the present study, we investigated the developmental expression of myelin-oligodendrocyte-specific glycolipid markers by means of ELISA assay. While immunoreactivity with antibodies recognising proligodendroblast (POA) antigen was unchanged, only minute amounts of the other glycolipid markers characteristic for more advanced stages of OLs maturation, such as 04 and 01 antigens, were expressed in pt brain. The degree of down-regulation was similar to that for MBP. Concomitantly, the level of in situ expression of the mutated PLP gene mRNA in glial cells of 14 day old pt brain was found to be as high as in age-matched controls. Northern blot analysis of developmental PLP gene expression showed a significant deficit of this message in pt brain, but only at more advanced developmental stages. However, aside from changes in myelin structure, no changes in glial cell number or morphology were evident by light microscopic examination of pt mutants. In contrast, electron microscopy revealed substantial abnormalities in pt oligodendrocyte cytoarchitecture, indicating functional impairment of intracellular transport and utilisation of myelin constituents. Thus, only POA expression is positively correlated with the unchanged content of OLs in pt brain, whereas decreases of 04 and 01 antigens, together with MBP immunoreactivity, are indicators of the degree of hypomyelination. Furthermore, oligodendrocyte differentiation appears to proceed normally in pt mutant brain up to the stage of PLP gene expression. Then, due to intracellular accumulation of this abnormal gene product, synthesis of PLP as well as the other myelin-specific constituents is inhibited by a "feed-back" control mechanism.
Metabolic Brain Disease 01/1996; 10(4):321-33. · 2.20 Impact Factor
-
Acta neurobiologiae experimentalis 02/1995; 55(3):221. · 2.11 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Electron microscopic immunocytochemical evaluation of localization and distribution of endothelins 1, 2 and 3 in the CA1 hippocampal sector in rats submitted to 10 min global cerebral ischemia was performed. The studies were done in different postischemic periods (10 min, 3, 6, 12 and 24 h) with postembedding immuno-gold technique for electron microscopy. Endothelin-like immunoreactivity was found in endothelial cells of hippocampal microvessels and in astrocytes, microglia, macrophages and in some axonal endings. The most pronounced changes appeared 24 h after ischemia. At that period all structural elements of blood-brain interphase: endothelium, basal membrane and perivascular astrocytic processes showed intensive endothelin-like immunoreactivity. Especially marked immunoreactivity was found in macrophages appearing in the proximity of microvessels. It has been stressed that ischemia-induced increased content of endothelin may play an important role in the pathogenesis of postischemic tissue abnormalities.
Folia neuropathologica / Association of Polish Neuropathologists and Medical Research Centre, Polish Academy of Sciences 02/1995; 33(4):221-30. · 1.23 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The subcellular distribution of glutamate and GABA in synapses of Mongolian gerbils hippocampus was examined using post-embedding immunogold staining method for electron microscopy. Immunolabelling was performed with 10 nm gold-antibody complexes for glutamate and GABA. The gold particle densities gave reliable information about the relative concentrations of these amino acid neurotransmitters. Our results indicate that ischemia leads to the temporal decrease of GABA-like immunoreactivity in symmetric synapses and a slight enhancement of the level of glutamate-like reactivity in asymmetric ones. The striking finding was a redistribution of glutamate-like immunoreactivity from neurons to glia. This suggests the capacity of glia to metabolize the excess of glutamate after ischemia. The disturbances at the level of neurotransmitters and their possible role in hippocampal neuronal injury were stressed.
Folia neuropathologica / Association of Polish Neuropathologists and Medical Research Centre, Polish Academy of Sciences 02/1995; 33(1):5-19. · 1.23 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The influence of staphylococcal alpha-toxin on the ultrastructure of hypothalamo-neurohypophysical system in the brain (nucleus supraopticus, nucleus paraventricularis, neurohypophysis) was studied in the rat. In neurohypophysis, an area lacking blood-brain barrier, alpha-toxin damaged both neuronal endings and capillary vessels. On the other hand in hypothalamus, where blood-brain barrier is present structural alterations were much less pronounced. Reactive gliosis, accordant with cell damage, was observed in the entire neurosecretory system. Putative mechanisms leading to brain damage after systemic administration of alpha-toxin, including direct disruption of cell membrane and induction of nitric oxide synthesis, are discussed.
Acta neurobiologiae experimentalis 02/1994; 54(3):219-25. · 2.11 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This study describes immunocytochemical distribution of the protein kinase C (PKC) subspecies: alpha, beta and gamma in the CAI sector of gerbil hippocampus. Immunolabelling was performed with 10 nm gold-antibody complexes against each of the PKC subspecies. The subspecies of PKC were expressed specifically in different populations of hippocampal cells. An enhanced PKC immunoreactivity was noted in the animals after ischemia. We propose that this phenomenon reflects an activation of PKC in the early phase of brain ischemia.
Folia Histochemica et Cytobiologica 02/1994; 32(2):71-7. · 0.81 Impact Factor
-
Acta neurobiologiae experimentalis 02/1994; 54(3):263. · 2.11 Impact Factor
