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Biomedical subjects

W Linss

Publications and source records attributed to W Linss.

At least 109 records · Page 6Linked to original sources
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↗
PubMed1976

Inverse localization of Ca2+ and La3+ high affinity binding sites of the red cell membrane.

Glutaraldehyde fixation in the presence of both 90 mM La3+ resulted in opaque deposits were also seen in specimens fixed in a glutaraldehyde-CaCl2 medium devoid of La3+. In that case only small amounts of a moderately opaque substance had accumulated or remained at the external surface of the erythrocyte membrane. Specimens previously fixed with Ca2+, La3+ supplemented glutaraldehyde lost their internal deposits completely during postifixation with OsO4. The findings provide evidence of Ca2+ high affinity binding sites at the internal surface of the erythrocyte membrane presumably identical with the filamentous matrix. Glycocalyx constituents are considered external Ca2+ low affinity binding sites, however, capable of accumulating high amounts of La3+ during glutaraldehyde fixation.

Binding Sites↗
PubMed1976

Calcium binding to the erythrocyte membrane.

Calcium binding sites of human red blood cells were localized by means of a method according to OSCHMAN and WALL (1972). The procedure resulted in multiple opaque deposits at the inner surface of the erythrocyte membrane.

Binding Sites↗
PubMed1975

[Studies on the osmotic resistance and the viability of amidinated erythrocytes].

The present studies are concerned with properties of amidinated erythrocytes. The reactions of dimethyladipimidate with proteins in solution and red blood cells, respectively, result in an intermolecular cross-linking. Following an amidination of human serum albumin or human gamma-globulin cross-linked products of increased molecular weight have been demonstrated by polyacrylamide gel and immune electrophoresis. Human erythrocytes previously amidinated intensely, exhibit a restricted motility of membrane particles and cross-linked hemoglobin. Intensely amidinated erythrocytes are resistant against distilled water, and they do no longer agglutinate. The findings presumably indicate an increased permeability of the amidinated red cell membrane. The glycolytic activity was found to be normal in moderately amidinated erythrocytes. In comparison with normal red blood cells, previously moderately amidinated erythrocytes of the rat become sequestered more quickly after re-injection into the vascular system.

Amidines↗
PubMed1975

Porosity and surface area of anionic resins: limitations in the employment of model substrates for the colloidal iron reaction.

Quantitative evaluations of the uptake of an acid ferric hydroxide sol revealed the iron binding of model substrates unrelated to their ion binding capacity. Electron microscopy showed iron particles bound exclusively or mainly to the surfaces of model substrates. Morphometric estimations resulted in a good agreement of the surface/volume ratio with the amount of bound iron. The results are discussed with regard to the steric hindrance of the colloidal iron reaction resulting in a nonstoichiometric interaction.

Anion Exchange Resins↗