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Biomedical subjects

B Fleischer

Publications and source records attributed to B Fleischer.

270 records · Page 15Linked to original sources
PubMed1969

Isolation and characterization of Golgi membranes from bovine liver.

Zonal centrifugation has been used to isolate a fraction from bovine liver which appears to be derived from the Golgi apparatus. Morphologically, the fraction consists mainly of sacs and tubular elements. Spherical inclusions, probably lipoproteins, are occasionally seen in negative stains of this material. The preparation is biochemically unique. UDP-galactose:N-acetyl glucosamine, galactosyl transferase activity is concentrated about 40-fold in this fraction compared to the homogenate. Rotenone- or antimycin-insensitive DPNH- or TPNH- cytochrome c reductase activities are 60-80% of the level of activities found in microsomes. Purified organelles from bovine liver such as plasma membranes, rough microsomes, mitochondria and nuclei have negligible levels of galactosyl transferase. Some activity is present in smooth microsomes but at a level compatible with the possible presence of Golgi membranes in this fraction. The Golgi fraction does not contain appreciable amounts of enzymes such as ATPase, 5'-nucleotidase, glycosidase, glucose-6-phosphatase, acid phosphatase, or succinate-cytochrome c reductase. Similar fractions isolated from bovine epididymis also have very high levels of galactosyl transferase. The fraction is heavily osmicated when incubated for long periods of time at elevated temperatures, a characteristic property of Golgi membranes.

Acid Phosphatase↗
PubMed1967

Fine structure of lipid-depleted mitochondria.

The fine structure of mitochondria and submitochondrial vesicles depleted of their lipid by extraction with aqueous acetone was studied. Thin sections of mitochondrial membranes depleted of more than 95% of their lipid retained the unit membrane structure. Densitometer tracings of the electron micrographs showed that the unit membrane of extracted mitochondria was, on the average, wider than that of unextracted controls and showed a greater variation in width. The outer membrane was lost in mitochondria from which 80-95% of the lipids was extracted. Inner membrane particles were present on submitochondrial vesicles depleted of up to 85% of their lipids. However, when more than 95% of the lipid was removed, few, if any, particles remained attached to the membranes but many particles were found unattached in the background. When lipid was restored to lipid-deficient preparations, the mitochondrial membranes were found to be devoid of inner membrane particles but were fully active with respect to succinate-cytochrome c reductase activity.

Animals↗
PubMed1967

Lipid composition of mitochondria from bovine heart, liver, and kidney.

Highly purified preparations of mitochondria from bovine heart, liver, and kidney were isolated and characterized by electron microscopy, oxidative phosphorylation ability, cytochrome c reductase activity, and cytochrome content. Components of lipid extracts of the preparations were determined by thin-layer chromatography, diethylaminoethyl-cellulose column chromatography, and spectrophotometric procedures. The major phospholipids were identified by their chromatographic behavior, IR spectrometry, and paper chromatography of their hydrolysis products. The lipid content of the mitochondria paralleled that of the components of the electron transfer chain, heart mitochondria being richest and liver mitochondria poorest in lipid. Heart mitochondria contain equal concentrations of coenzyme Q and cholesterol (1%); the highest cholesterol content (4.7%) was found in mitochondria from kidney. The phospholipids of mitochondria from the three organs were qualitatively and quantitatively very similar. The major polar lipid components (cardiolipin, choline glycerophosphatides, and ethanolamine glycerophosphatides) were present in a molar ratio of 1:4:4. It is suggested that mitochondria from different sources contain characteristic lipids, mainly phospholipids, of which cardiolipin is particularly diagnostic of the source of the mitochondria.

Animals↗
PubMedDate not supplied

Acquisition of specific cytotoxic activity by human T4+ T lymphocytes in culture.

Mature human T lymphocytes can be separated by monoclonal antibodies OKT4 and OKT8 according to their surface phenotypes into T4+T8- and T4-T8+ subsets. From short-term experiments using bulk cultures, the helper/inducer function has been assigned to the T4+T8- subset and the cytotoxic/suppressor function to the T4-T8+ subset. Thus if T lymphocytes are separated after stimulation in a mixed lymphocyte reaction (MLR), the entire cytotoxic activity is found in the T4-T8+ fraction whereas the T4+T8- fraction shows no detectable cytotoxicity. If, however, T lymphocytes are cloned after MLR and grown in long-term culture, a surprisingly large fraction of T4+ T lymphocyte clones (TLC) shows cytotoxic activity. Here we report that T4+ TLC can acquire specific cytotoxicity during in vitro cultivation.

Antibodies, Monoclonal↗
PubMedDate not supplied

Correlation of synovial fluid interleukin 6 (IL-6) activities with IgG concentrations in patients with inflammatory joint disease and osteoarthritis.

Synovial fluids of patients with rheumatoid arthritis, osteoarthritis, psoriatic arthritis, reactive arthritis and Reiter's syndrome were examined for their concentrations of interleukin 6 (IL-6) in a proliferation assay with the IL-6 dependent hybridoma cell line B13.29 (subclone B9). IL-6 activity was significantly higher in the synovial fluids of patients with rheumatoid arthritis and psoriatic arthritis than in patients with osteoarthritis. Significant correlations were shown between the concentrations of synovial fluid IL-6 and IgG. These findings may contribute to the understanding of the enhanced immunoglobulin production by synovial mononuclear cells in patients with inflammatory joint disease.

Adult↗
PubMedDate not supplied

Phospholipase C treatment of mitochondria.

Heavy beef heart mitochondria depleted of phospholipids by treatment with phospholipase C followed by removal of the by products by lipase treatment or sonication in pentane were analyzed by electron microscopy, chemical analysis and assays of enzymatic activities. The results indicate that diglycerides are present after phospholipase C treatment and are inhibitors of NADH-cytochrome c reductase. After removal of diglycerides with lipase treatment, a phospholipid requirement for NADH-cytochrome c reductase could be demonstrated.

Animals↗