MMM - The molecular model of memory.

Identifying mechanisms underlying neurons ability to process information including acquisition, storage, and retrieval plays an important role in the understanding of the different types of memory, pathogenesis of many neurological diseases affecting memory and therapeutic target discovery. However, the traditional understanding of the mechanisms of memory associated with the electrical signals having a unique combination of frequency and amplitude does not answer the question how the memories can survive for life-long periods of time, while exposed to synaptic noise. Recent evidence suggests that, apart from neuronal circuits, a diversity of the molecular memory (MM) carriers, are essential for memory performance.

[Ultrastructural study of podocyte alterations in non proliferative glomerulopathy].

Unlabelled: Ultrastructural changes in podocytes are an important diagnostic and prognostic marker for nephropathies. However, the biomedical understanding of detected submicroscopic changes in podocytes remains controversial.

Objective: To investigate the relationship between the ultrastructural changes of podocytes (fusion of cytopodia and denudation of the basement membrane as a result of their desquamation) with a number of clinical and laboratory indicators of kidney dysfunction in case of non-proliferative glomerulopathies (NPGP).

[CALCIFYING NANOPARTICLES IN PATHOMORPHOGENESIS OF STRUCTURAL LESIONS OF HEART VALVES].

Over the last 10 years, calcifying nanoparticles (CNP) have attracted attention as structures detected. together with many other nanostructures in biopsies from patients operated for the correction of aortic valve malformations. The results of the present work performed with the use of high-resolution transmission and scanning electron microscopes agree on the whole with the data of other authors.

Identification of cardiac stem cells within mature cardiac myocytes.

Cardiac stem cells are described in a number of mammalian species including humans. Cardiac stem cell clusters consisting of both lineage-negative and partially committed cells are generally identified between contracting cardiac myocytes. In the present study, c-kit(+), Sca(+), and Isl1(+) stem cells were revealed to be located inside the sarcoplasm of cardiac myocytes in myocardial cell cultures derived from newborn, 20-, and 40-day-old rats.

Intestinal injury can be reduced by intra-arterial postischemic perfusion with hypertonic saline.

Aim: To investigate the effect of local intestinal perfusion with hypertonic saline (HTS) on intestinal ischemia-reperfusion injury (IRI) in both ex vivo and in vivo rat models.

Methods: All experiments were performed on male Wistar rats anesthetized with pentobarbital sodium given intraperitoneally at a dose of 60 mg/kg. Ex vivo vascularly perfused rat intestine was subjected to 60-min ischemia and either 30-min reperfusion with isotonic buffer (controls), or 5 min with HTS of 365 or 415 mOsm/L osmolarity (HTS(365mOsm) or HTS(415mOsm), respectively) followed by 25-min reperfusion with isotonic buffer.

[Plasma membrane focal defects in structurally normal cells].

The technique of perfusion fixation through the rat kidney vasculature was modified to ensure the highest possible level of cell preservation close to that under in vivo conditions. Electron microscopic analysis of the tissue specimens treated in such a way revealed local defects of the plasma membrane in a number of cells than that otherwise looked normal. These findings together with the evidence for reparability of such defects and some data on the purely artificial nature of certain alterations should be taken into consideration in order to avoid misinterpretations while diagnosing the biopsy specimens.

[Type 3 membranoproliferative glomerulonephritis: an unusual variety of well-known pathology].

Light microscopy, immunohistochemistry, and submiscroscopy were used to study a renal biopsy specimen obtained from a 51-year-old old male suffering from type 3 membranoproliferative glomerulonephritis (MPGN-3) concurrent with HCV infection. Along with the signs characteristic of MPGN-3 (glomerulosclerosis; crescents; subendothelial and subepithelial deposits; proliferation of mesangial and endothelial cells), abundant pro- and myelocytes were found in the glomerular capillary lumens with active granular formation in the Golgi apparatus and with granular exocytosis into the glomerular basement membrane. Apoptotic elements were recorded among both glomerular and tubular epithelial cells.

[Choice of tools for ambulatory uvulopalatoplasty on the basis of experimental and clinical studies].

We studied interaction of a radiofrequency scalpel and a semiconductor laser with the tissue phantom. The heated part of the phantom can be easily removed and measured for size of the coagulated area. We investigated to what extent the width of the coagulation necrosis along the incision is influenced by the power and speed of each instrument used for incision.

[Ultrastructural and metabolic characteristics of the thyrocytes exposed to cyclophosphane].

Ultrastructural, morphometric and metabolic characteristics were studied in thyrocytes of 96 mice treated with immunosuppressing and cytostatic drug cyclophosphamide (CY), injected intraperitoneally every other day either for a short time (up to 6 days) in high doses (400 mg/kg) or for a long time (up to 70 days) in moderate doses (40 mg/kg). High doses of CY caused the reduction in thyrocyte height, NADH-diaphorase activity in their cytoplasm and protein content in the follicular colloid as compared to these parameters in a control group. The cisterns of rough endoplasmic reticulum (RER) underwent swelling and deformation with the loss of electron density of their contents.

[Intensive drying of grids after lead citrate staining lowers precipitate contamination on the surface of ultrathin sections].

Two techniques are proposed to minimize precipitate contamination of ultrathin sections after lead citrate staining. According to the first one, stained and washed grids are placed, sections downward, on a stack of filter papers. The second one involves a consecutive washing of grids with distilled water, 96% ethanol, and n-hexane.

[Modernization of the methods for detecting NADH diaphorase and glucose-6-phosphatase at the light-optical level].

A technique for NADH-diaphorase and glucose-6-phosphatase activity visualization at the light microscope level has been essentially modified by the use of a short pre-fixation of cryostat sections in a gluteraldehyde-containing fixative followed by a prolonged (18-20 h) incubation in the chilled (4-6 degrees C) standard media. Besides, for revealing NADH-diaphorase Triton X-100 is recommended to add to the incubation medium. The offered technical modifications secure a high staining intensity and specificity of both histochemical reactions tested without any substantial sophistication of the procedure.

[Immunoglobulin filtration and reabsorption as possible factors in the pathogenesis of chronic glomerulonephritis. Clinical, immunomorphological and histoenzymological research].

Kidney biopsy specimens obtained from a group of individuals with chronic glomerulonephritis (CGN) have been processed for light and electron microscopic immunolocalization of total immunoglobulins (Igs). In a few cases, acid phosphatase (ACPase), a lysosomal enzyme marker, was ultrastructurally visualized. In the glomeruli, horseradish peroxidase-stained Igs were revealed in capillary lumina, urinary spaces and in transit through occasional loci of the glomerular basal membranes while ACPase-containing lysosomes resided both within and outside the cells.

[Endoplasmic reticulum (a review of the literature)].

Recent data on the structural and molecular organisation of the endoplasmic reticulum (ER) are reviewed. A special attention is paid to the mechanism of soluble and integral membrane protein translocation across the ER bilayer. A model of phospholipid-coupled polypeptide translocation is introduced served to overcome hydrophobic and (or) conformational constraints during the passage of polar amino acid residues within a polar environment of the ER membrane.

[Nd:YAG laser radiation alters the proteolytic resistance of the liver tissue proteins in rats].

Small tissue strips were excised from rat liver and exposed to extensive irradiation with Nd:YAG laser followed by homogenization and spectrophotometric detection of 5% TCA-soluble protein fractions (oligopeptides) in both supernatants and 5NKOH-soluble sediments of the irradiated specimens. Trypsin along, or with chemotrypsin was added to the specimens to evaluate their proteolytic resistance during and after incubation for 24 h in the proteinase(s). The results showed that Nd:YAG laser irradiation resulted in significantly more oligopeptides following either schedule of the proteolysis employed in both supernatants and sediments as compared to the unaffected proteolytically tested specimens.

[In the dying cell secretory protein diffuses through the membranes into the cytosol].

Anti-horseradish peroxidase IgG (a-HRP) secreting hybridoma lymphoblasts grown subcutaneously in recipient mice have been studied light and electron microscopically 30-120 min following capitation of the animals. Conventional HRP-DAB immunocytochemical staining was performed for demonstration of a-HRP which in the living cells was restricted to the rough endoplasmic reticulum, the perinuclear cisterns, the Golgi apparatus and some microvesicles. 30 min after death in a number of the cells a-HRP began to invade the cytosol leaving, however, the nucleus and mitochondrial matrix free of the secretory marker.

[Defining the optimal conditions for immunoperoxidase cytochemistry at the submicroscopic level].

The authors tested a number of experimental protocols and chemicals known to facilitate permeabilization of tissues to immunoperoxidase markers without ultrastructural alterations of the cells to be examined. Monoclonal antibodies producing hybridoma lymphomas served as a primary test object. None of the procedures employed (i.

[The ultrastructure of the circumpulpal dentin of the human tooth].

Ultrastructure of cellular and extracellular constituents of the predentin and adjacent strip of dentin was investigated in both erupted and unerupted but completely shaped third molars of human adults using cautious fixation and demineralization techniques. The odontoblast processes (OP) were slightly bent at their bases to run further straight and parallel to each other across dentin and predentin. The OP cytoplasm contained numerous microfilaments and solitary microtubules.

[Electron histochemical characteristics of laser necrosis].

Linear or dot-shaped lesions were inflicted on rat liver with Nd:YAG laser, and fine structural alterations of hepatocytes were studied in the specimens processed for an endoplasmic reticulum (ER) marker glucose-6-phosphatase (GP). 5-7 s after irradiation a severe cell damage and GP inhibition occurred near the lesions, with less injured cells located laterally. 24 hr later the zone of the necrosis increased markedly.

Further ultracytochemical analysis of rat adenohypophyseal cells: detection of two distinct enzyme activities within a single cell.

In an effort to ascertain whether a lysosomal enzyme, aryl sulphatase (ArSase), might share the same cell and, or, the same intracellular structure(s) with a histochemical Golgi apparatus marker, thiamine pyrophosphatase (TPPase), in rat pituitary mammotrophs and somatotrophs a technique for a selective demonstration of both enzyme activities within a single specimen has been developed. The technique is based on the selective dissolution of TPPase-related precipitates with 50% sulphuric acid in an ultrathin section of a pituitary specimen processed consecutively for ArSase and TPPase. The analysis of pairs of micrographs displaying the same structures before and after treatment with sulphuric acid has shown that TPPase-related precipitates are located mainly in the trans-Golgi lamellae while ArSase-related precipitates (resistant to sulphuric acid) could be found in both GERL and its derivatives (lysosomes, immature secretion granules) and in the TPPase-reactive trans-Golgi pole in both cell types studied.

[Submicroscopic study of adenohypophyseal cells with the hypophysis incubated in a hypertonic solution. II. Differential analysis of the intracellular distribution of arylsulfatase and thiamine pyrophosphatase within a single cell].

In the rat pituitary gland exposed to an hour incubation in the medium containing 1.65 M sucrose activities of aryl sulphatase (AS) and thiamine pyrophosphatase (TPP) were successively defined within a single specimen. After the detection and registration of both enzyme activities with the electron microscope ultrathin sections were processed with 50% H2SO4 resulting in the complete removal of the reaction products for TPP.

[Submicroscopic study of adenohypophyseal cells with the hypophysis incubated in a hypertonic solution. I. The distribution of acid phosphatase, thiamine pyrophosphatase and arylsulfatase activities].

In the rat adenohypophyseal mammotrophs and somatotrophs, activities of acid phosphatase, thiamine pyrophosphatase and aryl sulphatase were defined after the incubation of the pituitary gland in the medium containing 1.65 M sucrose. Following 60--120 minutes of the incubation the above enzymes were found, in addition to their usual sites, in all cisternae of the Golgi apparatus and the rough endoplasmic reticulum as well as within the perinuclear cisternae.