Biomedical subjects

K Augsten

Publications and source records attributed to K Augsten.

At least 37 records · Page 2Linked to original sources

PubMed1981

Scanning electron microscopical characterization of La3+- and concanavalin A-induced aggregations of untreated and neuraminidase-treated human erythrocytes.

The aggregates of washed control and NANAse-treated human red blood cells (RBC) were characterized by scanning electron microscopy (SEM). Aggregation of RBC was performed under well-defined laminar shear conditions (78.6 S-1) in a horizontally arranged coaxial cylinder system. Generally, with increasing La3+ concentration in the PBS the aggregates became larger and the contact between the RBC "more intensive". This was evidenced by more cells per aggregate, an enlargement of contact areas, a change of cell shape in the contact region and signs of fusion phenomena. Especially at high La3+ concentrations on the cell surface of treated and untreated RBC some deposits were seen by SEM which are possibly La3+- phosphate precipitates. Neuraminidase treatment promoted the described La3+ effects. Concanavalin A-induced RBC agglutinates were different from the more spherical former ones and showed a network-like morphology. The conclusions drawn on the basis of light and scanning electron microscopical investigations are confirmed by quantitative values of an aggregation index estimated in parallel.

Cell Aggregation↗

PubMed1979

Effect of potential cytostatic and immune modulating chemicals on the plasma membrane of red blood cells (RBC) as revealed by osmotic hemolysis, cell electrophoresis and scanning electron microscopy (SEM).

The influence on red blood cells (RBC) of two cancerostatic-(ZIMET 3106 and ZIMET 3393) and two immunomodulating agents (ZIMET 3164 and ZIMET 86/76) administered subcutaneously, or intraperitoneally in case of the radiolabelled N-mustard compounds, to mice, was studied by means of measurements of the radiolabelled compounds in blood, by cell electrophoresis, filipin-induced hemolysis of pretreated RBC and by scanning electronmicroscopy. The portion of doses applied which binds to RBC-surface decreases in the sequence of ZIMET 3106, ZIMET 3164, ZIMET 3393 and ZIMET 86/76. However, the highest reduction of the electrophoretic mobility and protection from filipin-induced hemolysis of pretreated RBC was found with ZIMET 3164. In both tests ZIMET 86/76 proved to be ineffective. These findings are in good agreement with the modifications demonstrated in pretreated RBC after filipin-induced hemolysis by means of SEM. The results presented point to a N-mustard specific interaction between the cholesterol of the membrane and/or other membrane constituents. However, these fundamental differences found in binding affinity, surface-charges and membrane interactions caused by the chemically similar compounds cannot be attributed merely to the N-mustard group.

Animals↗

PubMed1979

[Inhibition of concanavalin A and phytohemagglutinine P mediated agglutination of L 1210 cells by different azomethines and possible relations to their cytostatic activity (author's transl)].

Compounds of a special azomethine type have been tested on their activity against concanavalin A and phytohemagglutinine P mediated agglutination of leukemia L 1210 cells. With exception of two compounds possessing a bis-(beta-hydroxyethyl) amino group at the phenyl moiety in para-position to the azomethine group all substances considerable inhibited agglutination of L 1210 cells. In vitro active concentrations are also obtained in animal experiments at least for a short time at the site of injection (i.p.) The importance of cellular reactions for effectivity in vivo is discussed.

Agglutination↗

PubMed1976

[Effect of 17beta-estradiol-3-monobenzoate on humoral antibody formation in mice].

17beta-Estradiol-3-monobenzoate injected s.c. in mice led to a dose-dependent stimulation of the global reticuloendothelial clearance function. Furthermore, a significant depression of serum hemagglutinin levels, being independent of the anitgen dose, was noticed. Although a slight decrease of antigen-sensitive (memory) cells was revealed, estradiol treatment before priming failed to impair immunological memory as assayed by hemagglutinin titers in the secondary reaction. Estradiol administration was followed by charakteristic organ weight changes (liver, thymus, adrenals). According to the literature it is suggested that estradiol, like diethylstilbestrol, is capable of depressing humoral antibody formation by differential effects on the reticuloendothelial system.

Adrenal Glands↗

PubMed1975

Modification of the surface structure of murine peritoneal macrophages following chemotherapy. A scanning electron microscopic study.

The effects on peritoneal macrophages of some chemotherapeutic agents administered subcutaneously to conventional male AB/Jena mice were studied. beta-[1-ethyl-(5-bis-(beta-chloroethyl)-aminobenzimidazolyl-(2)]-DL-alanine (IMET 2925), beta-[1-phenyl-5-bis-(beta-chloroethyl)-amino-benzimidazolyl-(2)]-DL-alanine (IMET 3164), and gamma-[1-phenyl-5-bis-(beta-chloroethyl)-amino-benzimidazolyl-(2)]-butyric acid (IMET 37/70) evoked a pronounced variation of the cell surface consisting in a shortening, coarsening and reduction in number of the microvili and other projections. Likewise, 1.3-bis(piperidinomethyl)-5-ethyl-5-phenyl-barbituric acid induced a flattening of the surface, but the structures appeared to be increased in number per area. Chlorambucil, 6-mercaptopurine, and 5-fluoro-uracil failed to provoke any obvious change in the threedimensional cell surface structure. These morphological findings are consistent with functional results reported previously.

Animals↗

PubMed1975

[In vitro evaluation of antiviral inhibitors by means of a turbidity method (author's transl)].

The paper presents a photometric method for the determination of virus-induced alterations (cytopathogenic effects) of cells based on nephelometric analysis. These were taken at varying time intervals after infection and with different multiplicity of infection. It was demonstrated that suppression of virus-induced CPE by the known inhibitors could also be followed by turbidity measurements. The in vitro experiments were carried out in the 2 following virus-cell-systems: Pseudorabies virus in chick-embryo cells and Mengo virus in FL-cells, respectively. According to these studies the measurements were extended to other virus strains and inhibitors (antibiotics, chemicals, and antimetabolites). The results obtained confirm the applicability of the photometric method for the screening of antiviral drugs.

Amantadine↗

PubMed1975

[FDA-hydrolysis for the fluorometrical evidence of a cell membrane alteration in peritoneal macrophages (author's transl)].

The enzymatic hydrolysis of fluoresceindiacetate (FDA) and the intracellular accumulation of fluorescein (fluorochromasia) by murine peritoneal macrophages were photometrically measured in cell suspensions. The intensity of fluorescence (excitation at lambda = 485 nm) was recorded by a right angel detector as a function of time, number of cells per ml, and FDA concentration, respectively. The meter response was found to be directly proportional up to the concentration of the fluorophor of 1.125 x 10(-6) M. In suspension the intensity caused by cells other than macrophages could be neglected. The rate of the fluorescein formation corresponds to the Michaelis-Menten constants (km = 8,34 x 10(-6) M.) Repeated in vivo administrations of some N-mustard benzimidazole derivatives were followed by competitive and non-competitive inhibition of the FDA-hydrolysis, respectively. Consequently, the fluorescence intensity varied, but without an concomitant adequate alteration of the non-specific (alpha-naphthyl acetate) esterase as was being measured by means of photometry of single macrophages in cell smears. Thus, this method seems to be suitable for quantitation of membrane (permeability) alteration induced experimentelly in macrophages.

Animals↗

PubMed1974