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C Michalec

Publications and source records attributed to C Michalec.

At least 19 recordsLinked to original sources
PubMed1992

Composition of lipid A in the S and R forms of Shigella dysenteriae serovar 1.

A chemical analysis was performed of lipid A, isolated by acid hydrolysis of the lipopolysaccharide from the S and R forms of Shigella dysenteriae serovar 1. Differences in the moiety of both lipids and sugars were compared. The lipid portion consisted of a homologous series of fatty acids ranging from C12:0 to C18:0 (predominant homologues, C12:0, C14:0 and C16:0) and the homologous series of 3-hydroxy acids ranging from C12:0 to C16:0 (predominant homologue, 3-OH-C14:0). The major sugar portion consisted of D-glucosamine. The toxicity of lipid A in mice (LD50) ranged between 300-400 micrograms/mouse, and values from the Limulus amebocyte lysate assay were recorded as titres of 10(-5) to 10(-6) mg/ml.

Animals↗
PubMed1989

Membranocystic lesion in the brain in cerebrotendinous xanthomatosis. Histochemical and ultrastructural study with evidence of its ceroid nature.

A case is described of cerebrotendinous xanthomatosis with purely neurological manifestations. Cholestanol deposition in both affected and unaffected brain regions was markedly increased, reaching 18.5-20.8% of the sterol fraction. The unilateral lesions localized in the basal ganglia and cerebellar white matter featured perivascular accumulation of foam cells containing apolar lipid and ceroid. Necrosis with lipid-rich debris was a frequent finding often accompanied by prominent collagen deposition. Within these lesions there were numerous refractile thick membranes which, according to lipid histochemical techniques, could be qualified as ceroid-type lipopigment. It is suggested that the ceroid membranes arise extracellularly directly from the lipid-rich debris. Ultrastructurally, they were composed of convolutes of highly organized trilaminar membranes about 15 nm thick similar to those seen in intracellular ceroid granules. The membranes were embedded in an amorphous substance of low or medium density and were identical in their general appearance, stainability and fine structure to the membranocystic lesion in Nasu-Hakola disease and to the extracellular ceroid in atherosclerotic plaques.

Adult↗
PubMed1979

Characteristics of lipid A-protein complex from endotoxin of Shigella dysenteriae type 1 (S and R strains).

Mild acetic acid hydrolysis of endotoxin (lipopolysaccharide-protein complex) of Shigella dysenteriae type 1 (S and R forms) yielded a lipid A-protein complex that consisted of amino acids, fatty acids, and sugar and, in terms of chemical composition, displayed no marked differences between the S and R forms. Its protein portion (53 to 56%) consisted of at least 16 amino acids. In the fatty acid portion (14 to 18%), myristic, 3-hydroxymyristic, palmitic, and stearic acids accounted for 50%. The sugar portion (10 to 12%) consisted solely of glucosamine. The remainder was unidentified substances, most of which contained phosphorus. Lipid A-protein complexes derived from both S and R forms were not toxic for mice in doses up to 1,000 microgram/mouse, but their Linulus test activity had increased considerably as compared with the starting lipopolysaccharide-protein complex material: from 10(-6) to 10(-10--10(-12) mg/ml. The lipid A-protein complexes were readily soluble in a water solution of triethylamine, in dimethyl sulfoxide, and in pyridine.

Amino Acids↗