Mráz P

Metabolic aspects of the synthesis and intra-axonal transport of noradrenaline storage vesicles

1. Constricted cat hypogastric nerve/inferior mesenteric ganglion preparations have been maintained for 24 hr in vitro, in either test‐tubes or a two compartment box, and used to study the roles of energy metabolism, protein synthesis and calcium ions in the synthesis and transport of noradrenaline storage vesicles in sympathetic neurones.

Both iso- and hyperosmotic ethanol stimulate release of hypothalamic thyrotropin-releasing hormone despite opposite effect on neuron volume

Previous studies have indicated that isosmolar, but not hyperosmolar, ethanol induces in vitro gonadotropin-releasing hormone secretion from the basal hypothalamus, presumably by causing cell swelling. Moreover, ethanol reduces secretion of another hypothalamic neuropeptide vasopressin. We have studied the acute effect of ethanol on specific hypophysiotropic basal and K+-stimulated thyrotropin-releasing hormone secretion in vitro especially in relation to cell swelling. Isosmotic 40-160 mM ethanol increased thyrotropin-releasing hormone release from the hypothalamic paraventricular nucleus and median eminence in a dose-dependent manner. Both a 30% decrease of osmolarity and isosmotic 80 mM ethanol induced 12% swelling of hypothalamic neurons. Hyperosmotic 80 mM or 160 mM ethanol induced release of thyrotropin-releasing hormone from both hypothalamic structures but did not cause cell swelling (80 mM) or even induced cell shrinkage (160 mM). Depletion of medium Ca2+ did not affect thyrotropin-releasing hormone secretion caused by either isosmotic or hyperosmotic ethanol. Our data indicate that both iso- and hyperosmotic ethanol stimulated release of hypophysiotropic thyrotropin-releasing hormone despite opposite effects on neuron volume. The mechanism of ethanol action appears complex and variable depending on the type of cell and neuropeptide affected.

Vaginal leukocyte characteristics in urogenital trichomoniasis

Morphological and functional characteristics of vaginal exudate leukocytes were examined in 47 patients with urogenital trichomoniasis. Electron microscopic morphology, viability, phagocytosis of Candida albicans blastospores and ability to undergo respiratory burst in the iodonitrotetrazolium reductase test were evaluated in these cells. Vaginal inflammatory leukocytes were almost exclusively polymorphonuclear neutrophils, and their concentration was positively correlated (r = 0.58; p<0.001) with the number of trichomonads in the exudate. Median leukocyte viability reached 39% and both phagocytic and tetrazolium reductase activities of these cells were significantly reduced in comparison with those of circulating polymorphonuclear leukocytes. Patients with a clinical picture of severe mucosal inflammation had significantly higher vaginal exudate leukocyte concentrations and viability than those without inflammatory signs. The possible role of vaginal leukocytes in the pathogenesis of urogenital trichomoniasis is discussed.

Mast cell infiltration in the wall of varicose veins

Varicose veins of the lower extremities are abnormally dilated, tortuous and elongated. The exact cause of vein dilatation has still not been established. Mast cells produce, store and release various types of vasoactive compounds (histamine, tryptase, prostaglandins, leukotrienes, and cytokines). Histamine enhances local vasopermeability and smooth muscle cell proliferation, leading to thickening of the intima. Tryptase can contribute to local vascular injury and subsequent weakness of the vascular wall causing varix formation. The aim of the present study was the comparison of mast cell infiltration in the wall of varicose and non-varicose veins. The mean mast cell density in the wall of varicose veins was 0.86 mast cell per mm2 and in healthy non-dilated vein walls, density was 1.23 mast cell per mm2. This difference was not statistically significant, therefore we could not confirm our hypothesis. Nevertheless, we suggest that mast cells could play an important role in the development of varices and the factor released by the mast cells should be further examined.

Expression of Constitutive Nitric Oxide Synthase Isoforms in Varicose Vein Wall; Preliminary Results

There are conflicting findings in literature about the structural changes of the primary varicose veins. NO (a potent vasodilatator) is synthesized by nitric oxide synthase (NOS). From 3 known NOS isoforms the two are constitutional: eNOS (endothelial NOS) and nNOS (neuronal NOS). 10 varicose and 10 control vein samples were processed by standard light microscopy and immuno-histochemica techniques using rabbit polyclonal antibodies against eNOS and nNOS. Antibodies expression was evaluated semiquantitatively and proved morphometrically by 2D-image analysis. total area of NOS isoforms expressions was determined by color analysis and color digital subtraction. The results showed discontinuous and significantly lower expression of both NOS isoforms the in the tunica media of varicose veins compared with the control group. For the statistical analysis the unpaired t-test was used. Our results suppose lower NO levels in varicose vein wall, deducing that varicose dilatation is due to other mechanism, and they contradict the results of previously published similar works.

GFAP-positive astrocytes are rare or absent in primary adult human brain tissue cultures

Traditionally, astrocytes are divided into fibrous and protoplasmic types based on their morphologic appearance. Here the cultures were prepared separately from the adult human cortical gray and white matter of brain biopsies. Both cultures differed only in the number of glial fibrillary acidic protein (GFAP)-positive cells. In the gray matter these were absent or rare, whereas in confluent cultures from the white matter they reached 0.1% of all cells. Three main morphologic types of GFAP-positive cells were found in this study: stellate, bipolar and large flat cells. GFAP-positive cells with two or three long processes mimic a neuron-like morphology. We did not find process-bearing cells expressing neuronal markers (MAP-2, NF, and N-CAM). The conflicting reports concerning GFAP immunostaining and the study dealing with the presence of putative neurons in adult human brain cultures are discussed with respect to these findings. The latter classification of astrocytes into type 1 and type 2 is based on immunostaining to A2B5 antigen: type 1 (GFAP+/A2B5−) and type 2 (GFAP+/A2B5+) astrocytes are proposed to be analogous to protoplasmic and fibrous astrocytes, respectively. In adult human brain cultures we found only small amount of A2B5-positive cells. Double immunofluorescence revealed that astroglial cells of similar fibrous or bipolar shape grown on one coverslip were either GFAP+/A2B5+ or GFAP+/A2B5−. On the other hand, the A2B5+/GFAP− immunophenotype was not observed. These results indicate that in general the cell phenotype from adult human brain tissue is not well established when they are in culture.

Subpopulation of nestin positive glial precursor cells occur in primary adult human brain cultures

Glial fibrillary acidic protein (GFAP) is an intermediate filament protein considered to be the best astroglial marker. However, the predominant cell population in adult human brain tissue cultures does not express GFAP; these cells have been termed “glia-like” cells. The basic question about histological origin of adult human brain cultures remains unanswered. Some authors showed that “glia-like” cells in adult human brain cultures might be of non-glial origin. We examined primary explant tissue cultures derived from 70 adult human brain biopsies. Within first 5–10 days approximately 5–10% of the small explants became attached. Outgrowing cells were mostly flat cells. These cells formed confluent layer over 3–6 weeks in culture. At confluence the cultures contained 2–5% of microglial cells, 0.1% GFAP-positive astrocytes, less than 0.01% oligodendrocytes and 95–98% GFAP-negative “glia-like” cells. This population of flat “glia-like” cells was positively stained for vimentin, fibronectin, and 20–30% of these cells stained for nestin. Our findings revealed that 1 mM dibutyryl-cAMP addition, in serum free conditions, induced a reversible stellation in 5-10% of the flat “glia-like” cells but did not induce the expression of GFAP or nestin in morphologically changed stellate cells. These results demonstrate that “glia-like” cells in primary adult human brain cultures constitute heterogeneous cell populations albeit with similar morphological features. Two distinct subpopulations have been shown: (i) the one immunostained for nestin; and (ii) the other reactive for dibutyryl-cAMP treatment.

Changes of Myocardial Mitochondria in Experimental Cardiomyopathies

Two models of experimental cardiomyofibrosis were developed: one based on a pathogenic diet, the other on administration of catecholamine. In both models marked alterations of the myocardial ultrastru