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Biomedical subjects

L C Mokrasch

Publications and source records attributed to L C Mokrasch.

At least 19 recordsLinked to original sources
PubMed1991

Studies on choline transport enhancement into fibroblasts from normals and Alzheimer's donors.

Human dental fibroblasts transport choline actively. This transport is inhibitable by hemicholinium-3. In this paper, choline transport into fibroblasts of normal donors (four cell lines) and into those of Alzheimer victims (four cell lines, age and sex matched to the normals) is accelerated by methylated xanthines, nicotine, and dexamethasone. At a caffeine concentration of 10 microM the stimulation of choline transport into normal cells averages 128% and into Alzheimer donor cells, 45%. 1 microM Dexamethasone stimulates choline influx by 86% in normal cells and 36% in Alzheimer cells. Nicotine enhances choline transport by 35% in normal cells and by 16% in Alzheimer cells. The implication is that if Alzheimer's disease is a cholinergic disorder, it may be amenable to transport-directed chemotherapies.

Aged↗
PubMed1990

Organic cations substituted for sodium are toxic to cultured rat glioma cells.

As a prelude to studying the sodium dependence of choline-transport systems, a number of organic compounds plus LiCl, CsCl and RbCl as sodium substitutes were tested for toxicity to maintain isoosmolality or ionic strength on cultured rat astrocytoma cells. In short term experiments (1 hour), tetramethylammonium chloride, triethanolammonium chloride, guanidinium chloride, tris hydrochloride, mannitol, sucrose, LiCl, RbCl and CsCl were well tolerated. In long term exposure (4 days), no compound was completely nontoxic as a sodium substitute, but sucrose, mannitol, LiCl, and RbCl allowed maximum cell survival.

Animals↗
PubMed1986

Cell membrane transport enzymes in cultured dermal fibroblasts from progeroid donors: a comparison to other human fibroblasts.

Cell membranes from progeroid fibroblasts had an elevated Na+, K+ ATPase. Ca++ ATPase and gamma-glutamyl transpeptidase were markedly decreased in progeroid fibroblast membranes. 5'-nucleotide phosphatase was unchanged, compared to age- and sex-matched normal fibroblast membranes. Fetal lung fibroblasts and dermal fibroblast from myotonic dystrophy victims had enzyme activities similar to those of the normal dermal fibroblasts.

Adolescent↗
PubMed1985

Transport enzymes in the cell membranes of cultured fibroblasts; alterations in dystrophic cells.

In support of the widely held belief that membrane defects are present in the muscular dystrophies, alterations have been found in some transport-related enzymes of cells from affected donors. Cell membranes were isolated from cultured dermal fibroblasts of victims of myotonic muscular dystrophy, and of Duchenne's muscular dystrophy, and from cells of normal age- and sex-matched donors. Myotonic cells had an elevated Na+, K+ ATPase. gamma-Glutamyl transpeptidase was elevated in Duchenne cells. Among all cells' 5'nucleotide phosphatase exhibited a remarkably constant specific activity.

5'-Nucleotidase↗
PubMed1984

Glutathione content of cultured cells and rodent brain regions: a specific fluorometric assay.

The glutathione contents of cultured cells and rodent brain were determined by a fluorometric procedure which eliminates the interference of endogenous histidine-containing compounds. Cultured neonatal rat and hamster astrocytes, human dermal fibroblasts, and mouse and rat brain regions were assayed. o-Phthalaldehyde forms a fluorescent complex with glutathione, oxidized glutathione, and histidyl compounds in the absence of added thiol. The reaction of histidyl compounds can be abolished by the addition of formaldehyde to the reaction mixtures. A 10-pmol quantity of glutathione can be measured in dilute formic acid extracts of milligram quantities of tissue.

Animals↗
PubMed1984

Vesicles with transport capability isolated from cultured fibroblasts.

Plasmalemmas from cultured human skin fibroblasts, isolated by a simple and reproducible method, can be converted to vesicles which are capable of active transport of aminoacid when glutathione is included within the vesicles. In the isolation, the plasmalemmas are stabilized with a Ricinus lectin, with preservation of the classic plasmalemma enzymes. The procedure has been applied successfully to a number of normal and abnormal human skin fibroblasts including those of myotonia dystrophica and progeria victims, and to the lung fibroblast WI-38. As part of a study of the characteristics of transport enzymes related to aging and to the muscular dystrophies in cultured fibroblasts, it was desirable to simplify the system by the use of vesicles prepared from the fibroblast plasmalemmas. The procedure described below is similar in some respects to that applied to another membranous system in the use of a lectin to stabilize the plasmalemma structure. The use of other stabilizing agents such as heavy metals and surfactant polymers which react with the membranes, but could compromise the reliability of the enzyme assays, was avoided. Since the focus of this study was on the enzymic systems of transport, the examination of facilitated diffusion or exchange was excluded. The well defined glutathione-dependent mechanism of aminoacid transport was examined to verify the competence of the vesicles for active transport and to confirm their sidedness. Other enzymes of transport, the ATPases, and membrane marker enzymes were also determined.

Adenosine Triphosphatases↗
PubMed1981

Hydrophobic proteins which bind cholinergic agonists from brains of lethargic mutant mice.

An investigation of hydrophobic proteins of synaptosomes isolated from the CNS tissue of the lethargic mutant mouse, which exhibits a behavioral epilepsy as the major visible effect of the mutant gene (lh), has revealed that the binding affinity of these proteolipid components for acetylcholine was higher than that observed in control (+/+) animals, a finding that may be directly related to the behavioral epilepsy.

Acetylcholine↗