Biomedical subjects

L Mavrina

Publications and source records attributed to L Mavrina.

8 recordsLinked to original sources

PubMed1994

[Improvement of storage capability of blood by the use of biocompatible absorbents].

A new filtration method for leucocyte and chloride ion depletion of erythrocyte concentrates in one step by DEAE cellulose was developed. After passage of the packed red cells through this filter material a chloride depletion of 70-80% and a leucocyte depletion of 90% could be reached. The 25 degrees C storage of this in-line-filtered red cells characterized by metabolic parameters (ATP, 2,3-DPG) suggests the possibility of a long-term red blood cell storage.

Absorption↗

PubMed1992

[Permselect--a new substance for leukocyte elimination].

Permselect particles consisting of purified plant cell wall ghosts obtained from the biomass of a suspension culture of Chenopodium album L. show a very high efficiency for leukocyte binding. A package containing 1 g dry Permselect eliminates 99-100% of leukocytes from 80 ml of fresh blood, preserved whole blood, or red blood cell concentrates. At comparable conditions Permselect shows a higher efficiency of leukocyte binding than commercial filter material (cotton, cellulose acetate). The vitality parameter of filtered erythrocytes and their stability during storage were not altered. The data are discussed with respect to causality of leukocyte binding to the pectin-containing surface of the cell wall particles.

Adsorption↗

PubMed1990

[Exclusion chromatography for the separation of cryoprotective agents from freeze-preserved blood cells].

A method for separating low molecular cryoprotectiva from freeze-conserved erythrocyte- and thrombocyte-concentrates by exclusion chromatography has been described. A new vesicular packing material has been used. Only 25 to 30 minutes are necessary in order to separate glycerol respectively dimethylsulphoxide (DMSO) completely from the cells. 86.5% of the erythrocytes and 75.4% of the thrombocytes were recovered after the separation process.

Blood Platelets↗

PubMed1990

[Hemapheresis using vesicular plant separation materials].

The present paper deals with the separation of cells from soluble compounds of blood by means of exclusion chromatography using a recently described vesicular packing material made from the cell wall framework of the small duckweed Wolffia arrhiza. The cells of the periphere blood are hardly retarded in passing through a packing of the vesicular material and eluted as sharp peak at an elution volume which is near to 30% of the column volume. The behavior of cells is similar to that of the excluded high molecular weight plasma proteins (e.g. serumalbumin). Low molecular weight solutes (e.g. salts, glucose, urea, kreatinin), but also substances of considerable molecular weight (e.g. myoglobin and Vitamin B12) which are usually difficult to separate by dialysis from serum, are eluted at nearly 100% of the packing volume and may be separated completely from cells and high molecular weight proteins. In vitro-Tests did not show a reduced vitality of eluted blood cells.

Blood Component Removal↗

PubMed1986

[Effect of platelet lysates on the proliferation of human bone marrow cells].

We tested the effect of a lysate from intact human platelets on human granulocyte-macrophage colony forming cells (GM-CFC) using the agar culture technique according to Pike and Robinson. Platelet lysate (PL) was prepared by freeze-thaw procedures of fresh and washed platelets. The results demonstrate the ability of PL to inhibit proliferation of GM-CFC up to about 60-80%. The inhibition is dose-dependent (a hyperbolic curve) and not caused by the influence of PL on CSF-production of feeder layer cells. Direct addition of CSF to the over layer (without feeder layer) maintains the inhibition of colony forming in human bone marrow by PL. The effect of PL may be related to physiological conditions of used platelets. Removal of granulocytes from the experimental system changes the inhibition characteristic of TL in a complex manner. In this case, the inhibition by TL on GM-CFC was found at low concentration only.

Blood Platelets↗

PubMed1985

[Evaluation of thrombocyte-induced immunomodulation in the tetanus-infected mouse].

The infection model of the mouse-tetanus assay was utilized in experiments to test for immunomodulating effects of thrombocyte preparations. It has been established that the substances of platelets cause alteration of tetanus reactivity in mice which occurs in two phases: a non-specific early effect starting only a few hours after application displaying a drastic increase of resistance of the animals to sporangium activity (possibly through enhancement of phagocytosis or bypass operation). A late phase of effectiveness develops after weeks, visible by an increase of morbidity and mortality following a repeated challenge which may be due to a decrease of a specific immune response. The immune modulating action is that of an inducer acting in xenogeneic systems and altering also the immune response to transplantation antigens.

Animals↗

PubMed1981

Active transport and mediated diffusion of glucose and other monosaccharides in Endomyces magnusii.

After growth on sucrose or glucose, Endomyces magnusii possess a monosaccharide uptake which resembles that of Saccharomyces cerevisiae (a high KT of uptake, preference for alpha-anomers of D-xylose and D-glucose, enhanced uptake during anaerobiosis, attainment of a diffusion equilibrium). The uptake is inhibited by other monosaccharides and especially strongly by D-galactose. In the absence of high concentrations of metabolizable sugars. E. magnusii develops a capacity to accumulate 3-O-methyl-D-glucose and D-xylose against a concentration gradient the new system displaying a high affinity for glucose (KT less than 0.1 mM), repression by glucose, mannose or galactose. Cycloheximide (0.2%) blocks the formation of the active system.

Ascomycota↗

PubMed1981

Anomeric specificity of the monosaccharide carrier in yeasts and yeast-like organisms.

The anomeric specificity of monosaccharide uptake was investigated in 42 species of yeasts and related mycelium-forming fungi. Differences in the uptake of anomers were determined by the following methods. (1) Shift of anomeric equilibrium in the outer medium caused by preferential uptake of one of the anomeric forms was monitored polarimetrically as induced mutarotation. (2) The uptake of 14C-D-glucose by cells was examined after addition of freshly prepared solutions of alpha- or beta-D-glucose. Most of the organisms examined display the Saccharomyces-type preference for the alpha-anomers of glucose and xylose which is caused by the higher affinity of the monosaccharide carrier for the alpha-pyranose configuration. The following genera show this type of preference (the number of species is given in parenthesis): Saccharomyces (5), Schizosaccharomyces (1), Endomycopsis (2), Eremascus (1), Endomyces (1), Pichia (1), Hansenula (1), Debaryomyces (2), Lipomyces (1), Willia (1), Nematospora (1), Kluyveromyces (2), Candida (5), Torulopsis (5), Cryptococcus (1). No anomeric specificity was shown by the following genera: Nadsonia (1), Dipodascus (2), Rhodotorula (5), Sporobolomyces (2), Bullera (1), Rhodosporidium (1). A parallel investigation of the concentration dependence of glucose uptake indicates that most yeasts possess a constitutive monosaccharide carrier characterized by the following features: a high maximum rate of uptake, a relatively low affinity, and preference for alpha-anomers. Besides this carrier the majority of these microorganisms possess a glucose-transporting carrier with a higher affinity and a lower capacity.

Biological Transport, Active↗