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Biomedical subjects

H Walter

Publications and source records attributed to H Walter.

At least 289 records · Page 16Linked to original sources
PubMed1978

Effect of intravesicular monovalent cations on the steady state of the phosphoenzyme of adenosine triphosphatase dependent on sodium and potassium ions in inside-out plasma-membrane vesicles.

Phosphorylation of the ATPase dependent on Na+ and K+ is promoted through the synergistic action of cations on both sides of the membrane. This phenomenon has been observed in plasma membrane vesicles isolated from sheep-kidney outer medulla which accept ATP from the outside surface (inside-out) and which are tight for sodium ions. In these inside-out vesicles phosphorylating capacity is low even in the presence of 100 mM extravesicular sodium chloride as is turnover of the enzyme. The level of the phosphoenzyme and the transient release of inorganic phosphate from the phosphoenzyme increases several-fold when sodium chloride is allowed to equilibrate over the membrane, 25 mM intravesicular NaCl is necessary to obtain the half-maximum level of the phosphoenzyme. This result shows that intravesicular (= extracellular) low affinity sites are involved in the phosphorylation. Intravesicular potassium ions modify the activating action of Na+ on the phosphorylation by increasing the steady state of the phosphoenzyme at low intravesicular sodium ion concentrations. This suggests that Na+ and K+ compete with each other for the intravesicular cation-binding site.

Adenosine Triphosphatases↗
PubMed1978

[The early cytological diagnosis of carcinoma of the uterine body with the Gravlee jet-washer (author's transl)].

A group of 108 patients who had a curettage for post-menopausal bleeding had a cytologic investigation with the Gravlee jet-washer prior to the curettage. 79 jet-washes (73.1%) were cytologically negative, nine (8.3%) were positive, two (1.8%) were false negative. False positive cytology did not occur. In 18 cases (16.6%) the material was insufficient for cytology. The accuracy of the jet-washings was 82%.

Cytodiagnosis↗
PubMed1977

Psoriasis vulgaris and genetic markers.

In a sample of n = 160 nonrelated male and female patients suffering from psoriasis Vulgaris, blood serum protein, and enzyme group typings have been carried out and compared with healthy controls from the same area (Rheinland-Pfalz). Marked statistically significant differences between patients and controls were found in none of the genetic blood polymorphisms considered here. However, combining previously published data from various authors with our own, significant associations between this skin disease and genetic polymorphisms such as MN, Gc, Gm (2), red cell acid phosphatase, and red cell phosphoglucomutase (PGM1) were seen. The possible reasons for these associations are discussed.

Acid Phosphatase↗
PubMed1977

Altered surface properties of Escherichia coli associated with a specific amino acid change in the S12 ribosomal protein of streptomycin-resistant mutants.

Escherichia coli mutants resistant to streptomycin exhibited differences in countercurrent distribution from the parental strains. The degree of difference from the parental strain correlated with the degree of restriction of translation and thus the particular strA allele. The changes in countercurrent distribution in the phase systems used probably resulted predominantly from surface charge alterations. The differences in countercurrent distribution in these and other mutants may be a useful selective technique to obtain different types of mutants for which specific selective techniques may not be available. In addition, it appears that the surface properties of cells, which determine their position in countercurrent distribution, are a function of the translational efficiency and fidelity, and that the surface of cells consists of a mosaic that is an expression of this translational fidelity.

Countercurrent Distribution↗
PubMed1977

Esterase D phenotypes in psoriasis vulgaris, atopic diseases and healthy controls.

Esterase D phenotypes have been determined in 162 patients with psoriasis vulgaris, 181 patients with atopic diseases and 110 healthy controls. All these samples are from the area of Rheinland-Pfalz (West Germany). The two patient samples show somewhat higher frequencies of Es D 1 and lower of Es D 2-1 phenotypes as compared to controls. These differences are, however, statistically not significant. The Es D1 frequency in controls (0.9045) is in accordance with those reported from other European populations.

Asthma↗
PubMed1977

On the genetic control of human serum albumin levels.

On 68 families with 134 children and on 115 mother-child pairs the serum albumin levels were examined by means of the single radial immundiffusion test after MANCINI et al. (1965). Neither age nor sex dependences were seen. Against that our materials indicate the existence of genetic factors controlling at least to some degree the concentration of this serum protein. Nevertheless, the serum albumin level is also influenced by non-genetic factors. At the present stage of research, however, it is not yet possible to separate exactly genetic and non-genetic variation from another.

Adult↗
PubMed1976

Partition in two-polymer aqueous phases reflects differences between membrane surface properties of erythrocytes, ghosts and membrane vesicles.

Partition of cells (defined as the percentage of added cells in the top phase) in dextran-polyethylene glycol aqueous two-phase systems is an extremely sensitive indicator of cell surface properties. By appropriate choice of polymer concentrations and salt composition and concentration one can, to some extent, select the membrane properties (e.g. charge (Walter, H. (1975) in Methods in Cell Biology (Prescott, D.M., ed.), Vol. 9, pp. 25-50, Academic Press, New York), lipid composition (Walter, H, Krob, E.J. and Brooks, D.E. (1976) Biochemistry, 15, 2959-2964)) that determine the partition behavior of cells (or membranes). In the present experiments we have obtained by partition information on separability, alteration and ensuing heterogeneity during preparation of human erythrocytes, ghosts and rightside-out and inside-out vesicles from human erythrocyte membranes. A phase system in which partition is greatly (although not exclusively) dtermined by membrane charge was used. It was found that: 1. The partition coefficients (and hence the membrane surfaces) of ghosts and of rightside-out vesicles differ from those of the erythrocytes from which they are derived. 2. Rightside-out and inside-out vesicles have different countercurrent distribution patterns with the rightside-out vesicles having the higher partition coefficient (probably reflecting higher membrane charge of the latter). 3. Rightside-out vesicles are highly heterogeneous membrane populations as evidenced by broader than theoretical countercurrent distribution curve which, in some experiments, even split into two populations outright. This heterogeneity is particularly interesting since the enzyme markers used to establish vesicle sidedness (Steck, T.L. (1974) in Methods in Membrane Biology (Korn, E.D., ed), Vol. 2, pp. 245-281, Plenum Press, New York) indicate "pure" rightside-out preparations. 4. Inside-out vesicles could, under no conditions tested, be rendered totally free of rightside-out vesicles according to the enzyme markers used to indicate vesicle sidedness (Steck, T.L. (1974) in Methods in Membrane Biology (Korn, E.D., ed), Vol. 2, pp. 245-281, Plenum Press, New York). A discussion of factors involved in the partition of the vesicles and ghosts together with analogies to the partition behavior of stored or in vitro modified human red blood cells is presented.

Acetylcholinesterase↗
PubMed1976

Membrane surface properties other than charge involved in cell separation by partition in polymer, aqueous two-phase systems.

When aqueous solutions of dextran and of poly-(ethylene glycol) are mixed above certain concentrations, immiscible, liquid two-phase systems are obtained which are useful for separating cells by partition. Some salts partition unequally between the phases, giving rise to an electrostatic potential difference between them. Partition of cells has therefore been thought to depend predominantly on membrane charge. We now report two instances in which membrane charge either does not determine or is not the main determinant of cell partition. (A) Cell partition coefficients in phase systems approaching the critical point (the component concentrations below which a homogeneous solution occurs) increase, even in phase systems in which the phase potential difference is practically zero. Furthermore, in such systems, the partition coefficient of (human) erythrocytes is not reduced by complete removal of sialic acid. (B) Rat and mouse erythrocytes have sizable partition coefficients in a phase system away from the critical point with no potential difference between the phases. Cell surface interaction with the polymers is probably responsible for cell partition in these cases. Partition studies on erythrocytes from nine mammalian species in phases near the critical point with and without electrostatic potential differences reveal major species-specific differences in the membrane charge/noncharge components. A correlation has been found, in phases near the critical point that have essentially no electrostatic potential difference, between partition coefficient and the ratio of poly/monounsaturated fatty acids in the membranes of red cells from different species. Our present results thus provide parameters for the separation of cells by partition in addition to or instead of membrane charge depending on the polymer and salt composition and concentration selected.

Animals↗