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W Linss

Publications and source records attributed to W Linss.

At least 73 records · Page 4Linked to original sources
PubMed1984

The histochemical detection of acetylcholine esterase--an indicator of the disintegration of membranes.

The presence of ACHE in erythrocytes membrane in vitro but not detectable ultrahistochemically has been explored as a sign of membranes disintegration. The final results of the investigations have shown, that the increase in ACHE activity of the erythrocyte membrane is a qualitative sign and a semiquantitative measure of serious disturbances in the membrane structure.

Acetylcholinesterase↗
PubMed1984

[Electron microscopic observations on the extrusion of enteroendocrine cells from the epithelium of the mouse small intestine].

By means of electronmicrographs it could be showed that enteroendocrine cells at the tips of the villi intestinalis are extruded in a way similar to other intestinal cells. They lose their contact to the basal lamina. An at first small process protrudes into the intestinal lumen. The cell as an entity can follow afterwards. Frequently this extrusion takes place together with neighbouring cells and as a consequence, there is a cell complex in the intestinal lumen which can be connected with the epithelium by means of a small cytoplasm bridge. A second way leads over rupturing of the protruding part of the cell and the extrusion of the cell residue.

Animals↗
PubMed1983

Acceleration of coagulation by spectrin-free erythrocytic vesicles. Evidence for lipid flip-flop during vesicle formation.

Spectrin-free erythrocytic vesicles isolated from outdated liquid-preserved blood samples show a distinct increase of the clot-promoting activity compared with membrane phospholipid equivalents of intact erythrocytes. We suppose that, among other remodelling processes, local spectrin detachment from the inner membrane surface may trigger a flip-flop-mediated disturbance of the membrane lipid asymmetry. The interactions of spectrin with the cytoplasmic membrane surface seem to be essential for the structural membrane integrity including the lipid asymmetry.

Blood Coagulation↗
PubMed1983

[Ultrastructural findings on cell extrusion of intestinal villi in mice].

Ultrastructural findings at the extrusion zone on the tips of the Villi intestinales in the jejunum of mice showed that the estrusion of cells can take place in various ways. One possibility is that, at first, a part of the cell is protruding into the lumen under reduction or loss of the microvilli. The rest of the cell is following, but the continuity of the epithelium is preserved. The cell remains adhered to its neighbours which adjoin in such a way that not gap can develop in the epithelium. Often the plasmalemma of the extruding cell is completely preserved. Sometimes a breaking up can be observed. Then the cytoplasm enters the intestinal lumen. On the other hand, the enterocyte can leave the epithelium after widening of the intercellular space and destruction of the cell connection. Then a gap is established and direct contact between the intestinal lumen and the basement membrane.

Animals↗
PubMed1983

Membrane alteration during banking of red blood cells.

Irreversible RBC membrane alterations take place during liquid storage (whole blood, RBC concentrates). Major membrane lesions are conformational changes of glycophorines, number reduction of A determinants and NaNa containing negatively charged groups, loss of phospholipids, expression of IgG receptors, redistribution of spectrin and vesiculation. Effects of these changes on the rheological and immunological cell properties as well as their importance for RBC elimination after reinfusion are discussed. Preliminary studies show that low temperature preservation of RBC (-25 degrees C) stabilizes the RBC membrane more extensively than liquid storage techniques.

Blood Banks↗
PubMed1982

Metabolic depletion of erythrocytes is accompanied by a decrease of sialic acid during blood bank storage: a reply.

Erythrocytes lose about 10% of their sialic acid during banking in ACD-AG medium. In contrast to these findings, Pessina et al. could not detect a significant banking-related sialic acid decrease. The present paper explains this discrepancy. The vesiculation of erythrocytes is mainly responsible for the observed sialic acid loss during blood preservation.

Blood Preservation↗
PubMed1982

[Erythrocyte vesiculation. 3. Building block analysis of vesicles from preserved blood].

The contents of total protein, haemoglobin, hexose, phospholipid and sialic acid of erythrocytic vesicles prepared from ACD-AG blood samples banked for 6 weeks were analyzed quantitatively. The results were discussed and compared with those of other authors. The bulk of vesicular haemoglobin is not released under hypotonic conditions. It can be determined with the haemiglobincyanide method in the presence of SDS.

Blood Preservation↗
PubMed1982

[Vesiculation of erythrocytes. 4. Quantification of vesiculation rates in standard fluid preservation].

The quantity of erythrocytic vesicles was estimated, which were produced after 6 weeks banking of ACD/AG and CPD/AG blood samples. The analytical and morphological dates of these vesicles allow calculation leading to the following conclusions: 1. After 6 weeks storage under blood banking conditions about 210 vesicles per erythrocyte were formed. 2. The vesiculation may serve as a possible explanation for storage dependent losses of sialic acid as well as phospholipids. 3. The vesiculation is accompanied by a reduction of the surface/volume ratio of the erythrocytes. This may be an important fact regarding the elimination of a part of stored cells via decreasing deformability of the red blood cells.

Blood Preservation↗
PubMed1982

[The altered membrane of the erythrocyte. I. Ultrahistochemical and biocellular investigations for the detection of activated acetylcholinesterase (ACHE) and demasking of IgG receptor sites (author's transl)].

Different states of the erythrocyte membrane with regard to its disintegration are characterized. The binding power of autologous and allogenic IgG, the degree of the activation of the membrane associated acetylcholinesterase (inhibited in the intact plasmalemma of red blood cells), and the membrane vesiculation served as criteria. The findings demonstrate that, obviously, the IgG binding increases in dependence on the extent of the disturbance of the membrane structure. The acetylcholinesterase is increasingly activated. The enzyme can be demonstrated by spectrophotometrical and ultrahistochemical methods. Microvesiculation is understood as expression of fundamental disturbances of the membrane structure. These disturbances express local remodelling processes in the membrane of banked red blood cells. Highly extended damage of red blood cells after mechanical stress, heat or urea incubation lead to comparatively high rates of vesiculation, partially even to cell fragmentation. Extremely spectrindeficient ghosts tend to microvesiculation, which leads to complete microvesicular decay of the ghost membrane. The membrane associated autologous IgG is demonstrated by means of immuneological and ultrahistochemical methods. Its importance as homeostatically effective immun-signal for the elimination of red blood cells aged in vivo or in vitro, ghosts and microvesicles by the reticulohistiocytic-system is evidenced by means of model experiments. Molecular mechanisms for unmasking of IgG-receptor sites and activation of acetylcholineesterase in the altered erythrocyte membrane are discussed.

Acetylcholinesterase↗
PubMed1981

Lipid segregation from human erythrocyte tethers.

Fluid shear force may deform point-attached erythrocytes to become droplike shaped and anchored by a single long or 2-4 short tethers. By addition of glutaraldehyde to the medium the cells were fixed such as to stabilize this deformation for ensuing SEM, freeze-fracture, fine structural, and ultrahistochemical studies. Freeze-fracture specimens revealed identical numbers and distribution patterns of membrane particles in both the membrane of tethers and of the droplike portions of red cells. Segregated vesicles most often were located adjacent to the attachment site of the tether. All of the vesicles were devoid of membrane particles. Irrespective of their length, the tethers were about 0.1 micrometer in diameter. Cross-sections of the tether membrane and the plasmalemma of the major part of the cell appeared identical. Ultrahistochemical studies revealed the same intensity of iron binding capacity and affinity to ferritin labelled anti AHP at either area of the deformed erythrocyte membrane. Segregating vesicles were also stained by colloidal iron and by fer-anti AHP. By means of the DAB-reaction no haemoglobin was demonstrated within the vesicles. All of these findings corroborate the notion, that lipid molecules were segregated from the membrane whose curvature increased considerably during the formation of the tether.

ABO Blood-Group System↗
PubMed1981

Erythrocyte vesiculation. 2. Membrane molecular transformation.

A population of vesicles 150 +/- 30 nm in diameter was isolated from banked human blood and the perturbation of their membrane studied. SDS polyacrylamide gel electrophoresis revealed the complete loss of spectrins from the vesicle membrane which was also depleted of various intrinsic proteins. In particular, severe reduction of protein 3 and glycophorin is consistent with the over 80% decline of intramembrane particles in either fracture face of the vesicle membrane. The stimulation of vesicle acetylcholinesterase is considered indicative of an initial disintegration associated with the segregation and rearrangement of membrane constituents. The findings are discussed with regard to the subcellular mechanisms of erythrocyte vesiculation.

Blood Preservation↗
PubMed1981

[Importance of the cell membrane for the sequestration of aged erythrocytes].

The erythrocyte membrane is an important cell organelle which determines the intravital life time of the cell in a decisive way. Their mechanic properties are closely connected with the metabolism of the cells. Increasing disturbance of the cellular metabolism especially in the course of biological aging leads to enhanced cell rigidity. It is supposed that the decreased elasticity of the aged erythrocytes in critical regions of the blood circulation (capillaries with a diameter of 2.5 to 3.0 micrometers) leads to pressure induced vesiculation and spherocytosis. It is possible that also IgG-receptors are demarked by this process. After passing a threshold concentration as immunobiological signals increased irreversible binding of IgG induces the sequestration of the erythrocytes by the erythrocyte destructing system.

Animals↗