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Biomedical subjects

W Linss

Publications and source records attributed to W Linss.

At least 91 records · Page 5Linked to original sources
PubMed1980

[Inverse binding of lectin to either area of the plasmalemma of the enucleating normoblast (author's transl)].

The study was concerned with properties of either area of the cell membrane of the enucleating erythroblast, i.e. the plasmalemma envelope of the nucleus under extrusion and the future membrane of the reticulocyte. The findings did not corroborate the notion of a decline of the negative surplus charge of the plasmalemmal envelope. At this area of the erythroblast membrane it was demonstrated an increased lectin binding associated with the loss of toluidine blue induced anisotropy.

Cell Nucleus↗
PubMed1979

Hypotonic unmasking of erythrocyte receptor sites.

The study reports on plasmalemmal perturbation of erythrocytes under osmotic stress. In comparison with isotonic human erythrocytes a 10 minutes incubation in 150 mosm sodium cacodylate pH 7.4 at 20 degrees C results in an increase of the anti AH P binding rate by a factor of two. 0.1 M N-acetyl galactosamine inhibits the binding of anti-AH P of both isotonic and hypotonic red cells. Contrary to isotonic mouse erythrocytes the agglutination with peritoneal murine leukocytes of hypotonic red cells is greatly enhanced provided the erythrocytes have been incubated in autologous serum. The findings are considered evidence of the unmasking of binding sites due to nonspecific rearrangement of membrane constituents.

Acetylgalactosamine↗
PubMed1979

Alteration of the enucleating erythroblast glycocalyx.

Plasmalemmal differentiation of the enucleating normoblast of rabbit and rat was studied by means of cytochemical methods and freeze-etching. Staining with colloidal iron revealed about identical amounts of iron particles bound to various areas of the normoblast membrane. Cationized ferritin and ruthenium red, likewise, failed in the demonstration of significant changes of the enucleating normoblast glycocalyx. Despite these findings the topo-optical staining with toluidine blue showed the plasmalemmal envelope of the protruding normoblast nucleus moderately birefringent, clearly discriminated from the intense anisotropic staining of the future reticulocyte membrane. The ferritin-labeled snail lectin anti AHP localized a great number of binding sites at the plasmalemmal envelope of the nucleus under extrusion. That is in sharp contrast with rather low lectin binding to the future reticulocyte membrane which amounts to about 30 to 50% of the nuclear envelope label. The findings provide evidence of unmasking of bindings sites of the normoblast membrane. Apparently, the effect is due to conformational changes of the cell membrane, rather than it could be attributed to degradation of glycoproteins. Moreover, enucleation kinetics may also be related to supramolecular changes of membrane structure albeit missing evidence for the rearrangement of membrane particles.

Animals↗
PubMed1979

CPC-PTA section staining of acid glycans.

A cetylpyridinium chloride-phosphotungstic acid procedure suggested by Kelényi and Kiss (1976) for the staining of mast cell granules in ultrathin sections was slightly modified with regard to pretreatment, pH of incubation, and rinsing of sections. The method also proved suitable for the demonstration of various mucosubstances and of cartilage proteoglycan aggrebates.

Animals↗
PubMed1979

Negative surplus charge of coated erythrocytes.

The effect on the net negative surface charge of single or multiple coating of erythrocytes was studied on human group A red cells previously washed and fixed. Single coating with either group A antiserum or protectin decreased the electrophoretic mobility of erythrocytes by 16% and 13%, respectively. Following an incubation in group A glycophorin or bovine submaxillary mucin of agglutinin coated cells, the electrophoretic mobility was restored or slightly increased compared with uncoated erythrocytes. Upon repeating this scheme, the second agglutinin binding again reduced these cells' cytophoretic mobility, and they were accelerated once more by a second coating with acid glycoprotein. Intensity and homogeneity of colloidal iron staining of uncoated and variously coated erythrocytes reflected their electrophoretic retardation and acceleration, respectively.

ABO Blood-Group System↗
PubMed1979

[Sialic acid content and IgG binding of the glycocalyx of preserved erythrocytes].

Fractions of light and heavy erythrocytes were separated by centrifugation from blood samples banked in ACD-AG medium at 4 degrees C for periods up to 6 weeks. Both light and heavy erythrocytes have lost about 4,9% of their content of sialic acids during banking for 6 weeks. This reduction is in accord with a 6%-decrease of their agglutination by means of alcian blue. It is, however, a variance with the inhibition of agglutination by anti-IgG sera. The present findings provide evidence for the role alterations of the red cell membrane may play in the process of recognition and phagocytosis of banked erythrocytes. With regard to these alterations we suggest two types of rapid elimination of transfused banked erythrocytes: a) Primary elimination refers to cells primarily loaded with immunoglobulins such as to get recognized and phagocytized by macrophages. b) Secondary elimination accounts for rigid erythrocytes suffering from additional degradation while retained in the spleen prior to their loading with immunoglobulins and ensuing phagocytosis. Secondary elimination is considered a process more relevant to reutilisation of banked blood.

Binding Sites, Antibody↗
PubMed1979

[A ruthenium red-osmium tetroxide section staining method (author's transl)].

We suggest a method for the section staining of polyanions by means of ruthenium red and osmium tetroxide. A 5 min incubation in diluted ruthenium red-OsO4 solution pH = 7.4 of ultrathin Durcupan-sections previously treated with sodium methoxide results in the opaque stining of mast cell granules, cartilage proteoglycans, and various epithelial mucosubstances.

Animals↗
PubMed1978

Toluidine blue staining of cartilage proteoglycan subunits.

Selective binding of toluidine blue to basophilic proteoglycans is the first stage of a staining method which proceeds to the formation of a heavy metal salt of the dyestuff. By means of this procedure matrix complexes of hyalin cartilage were stained such as to display granular subunits about 25 to 35 A in diameter. The findings are interpreted as the demonstration of proteoglycan constituents of chondromucin aggregates.

Animals↗
PubMed1978

Phosphorylated spectrins are likely constituents of major Ca2+ affinity sites.

Fixation with Ca2+ -glutaraldehyde of ghosts results in opaque membrane associated deposits similar to Ca2+ binding sites of native human erythrocytes. Following brief incubation in an ATP medium the number and size of major Ca2+ affinity sites is considerably enhanced. In addition to major Ca2+ affinity sites multiple minor sites are lining either aspect of the ghost membrane. Ghosts fixed with EDTA-glutaraldehyde are devoid of major Ca2+ affinity sites and they exhibit extreme low overall opacity. Ghosts previously partially despectrinated by incubation in 0.5 mM EDTA have lost major Ca2+ affinity sites, although minor binding sites appear unimpaired. The findings provide evidence of the demonstration of phosphorylated spectrins in major Ca2+ affinity sites.

Binding Sites↗
PubMed1978

[Conformational alteration of the Antennulae microvillares (author's transl)].

Brush border cells of the rectal mucosa of the rat previously fixed with glutaraldehyde and OsO4 exhibit branched antennulae microvillares. This regular type of antennulae changes to become a cap-like layer at the tip of the microvilli following the incubation in 100 mM EDTA and 1 M guanidinium hydrochloride, respectively, of the native mucosa. During an incubation in isotonic sucrose the antennulae are transformed to moderately branched rod-like forms. The findings suggest a collaps of antennulae whose anchoring at the membrane of the microvilli appears to be resistant and, presumably, may prevent the loss of this mucosubstance.

Animals↗
PubMed1978

Electron microscopic toluidine blue staining of the erythrocyte membrane.

Incubation in ferricyanide medium of toluidine blue stained erythrocytes produces opaque precipitates lining either aspect of the cell membrane. In addition, granular and needle-shaped precipitates occupy an intra- or extracellular position. Staining of the outer aspect of the membrane may reflect toluidine blue binding of the erythrocyte glycocalyx. Precipitates at the inner leaflet resemble Ca2+ affinity sites which were considered phosphorylated spectrins. Comparison with the light microscopic topo-optical toluidine blue reaction proved most of the electron dense precitates noncontributive to anisotropic staining.

Erythrocyte Membrane↗
PubMed1977

Reversible conformational changes of plasmalemmal glycoproteins.

Repeated incubations of human red blood cells in low ionic isotonic sucrose result in an instantaneous agglutination. In the same medium which had caused the agglutination, erythrocytes completely disagglutinate within 60 to 90 min. Disagglutination is accompanied by the efflux of cellular ions, which causes a 500-fold increase of extracellular K+. Decomposition of agglutinates occurs at once upon addition to the medium of about 3 mM KCL. It will be inhibited for hours, if the medium is renewed twice an hour. Erythrocytes washed successively with phosphate buffered saline and isotonic sucrose are devoid of adhering blood plasma proteins. If these cells were fixed with glutaraldehyde in isotonic sucrose they had lost a) their anisotropic staining with toluidine blue, and b) most of their colloidal iron binding capacity. The staining with ruthenium red and the electrophoretic velocity of these erythrocytes apparently were identical with the controls. The findings are considered evidence of the reversible unfolding of glycocalyx glycoproteins in the low ionic medium.

Animals↗
PubMed1977

Adsorbed proteins mask negatively charged sites of the erythrocyte glycocalyx.

Protein masking of charged sites of the erythrocyte glycocalyx was studied by means of the colloidal iron affinity. Washed red cells were fixed with glutaraldehyde such as to stabilize their glycocalyx and to inhibit conformational changes during posttreatment. Following the incubation in an ionic protein solution, proteins adsorbed to the cell surface were insolubilized by repeated treatment with low ionic isotonic surcose. Erythrocytes coated with precipitated proteins exhibited a rough surface. Their iron binding capacity was reduced considerably. In comparison with serum albumin, masking by gamma globulin was more efficient, apparently, because of its insolubility in low ionic media. High ionic incubation of coated erythrocytes resolubilized adsorbed proteins and unmasked negatively charged groups of the glycocalyx.

Erythrocyte Membrane↗
PubMed1977

[Electronmicroscopic detection of cation binding sites on the erythrocyte membrane].

Numerous Ca2+-binding sites were localized ultrahistochemically at the inner surface of the erythrocyte membrane and small amounts at the outer surface. La3+-binding sites were demonstrated at the outer surface only. The results were discussed in relationship to the binding capacity of the filamentous matrix and the glycocalyx of the human erythrocyte membrane.

Binding Sites↗
PubMed1977

[Electron-microscopy studies of capillaries of the dialyser C-DAK 4 with reference to multiple use].

The results of the examinations show that the integrity of the wall of the capillary is not impaired by the process of purification, but, on the other hand, functional changes by thrombotic occlusion as well as disseminated deposits of protein may be expected. The temporary regime of dialysis mus consider this fact in order to achieve a constant effect. But on principle from the clinical experience and on the basis of these results of examinations a manifold use of the dialysator of the capillary in carrying out the purification measures mentioned may be recommended.

Capillary Permeability↗