Zeitschriften

Ohne Zusammenfassung     

Apolipoprotein B retention in the grossly normal and atherosclerotic human aorta.

Apoliporotein B (apoB) was measured in buffer-extracted homogenates of grossly normal and artherosclerotic human aortic intima by means of an electroimmunoassay procedure. The apoB values which were expressed as microgram per mg tissue dry weight, varied widely, ranging from 0.34 to 18.45 in normal intima and from 0.8 to 12.5 in fatty fibrous plaques. No consistent differences in apoB content were found between normal intimas from thoracic and abdominal aortic regions. There was a statistically significant positive correlation between the quantity of buffer-extractable apoB in normal regions and the plasma cholesterol and triglyceride concentration. Buffer-extractable apoB values were significantly higher in fatty fibrous plaques than in ulcerated lesions from the same vessel. However, fatty fibrous plaque apoB values were significantly lower than those from grossly normal regions from the same aorta, although the topographical distribution of apoB was more widespread in plaques than in normal regions, as shown by immunofluorescence studies. This apparent discrepancy reflected the incomplete extraction of apoB from plaques as contrasted to normal regions. The relatively loosely bound apoB, extractable by standard buffers, may represent intact low density lipoprotein (LDL) and/or very low density lipoprotein (VLDL), while the tightly bound fraction may represent insoluble complexes of intact lipoproteins within the plaque or delipidated apoB.     

Correlation in the human aorta of APO B fractions with tissue cholesterol and collagen content.

The amounts of buffer- and Triton-extracted apo B (LDL-protein), as well as the sum of these two fractions, were correlated with the total tissue cholesterol and hydroxyproline content (as a measure of collagen) in grossly normal intima, fatty streaks, and fibrous plaques of human aortas obtained at autopsy. Quantitative values of buffer- and Triton-extracted apo B were obtained by sequentially extracting homogenates of aortic intima with an aqueous buffer and one containing Triton X-100, and measuring the apo B content in each extract by an electroimmunoassay relative to plasma LDL or Triton-treated LDL. Significant positive correlations were obtained between the following: tissue cholesterol and both buffer-extracted and total-extracted apo B in grossly normal intima; tissue cholesterol and Triton-extracted apo B in microdissected fibrotic caps and cores of fibrous plaques, as well as in whole plaques. A positive correlation was also obtained between tissue cholesterol and total-extracted apo B in the necrotic core. A significant negative correlation was found between Triton-extracted apo B and collagen in whole plaques. The calculated mean percent of total tissue cholesterol in the different aortic regions that could be present as part of an intact LDL particle were: 100% in grossly normal intima, 16% in fatty streaks, and 11% in fibrous plaques. The positive correlation between Triton-extracted apo B and cholesterol in plaques suggests one or both of the following: the extracellular pool of cholesterol or some material increasing concurrently with cholesterol interacts with apo B or another part of the LDL particle; or the apo B containing lipoprotein is trapped in the hydrophobic environment of extracellular lipid. Both possibilities would render the particle less soluble in aqueous buffers. The negative correlation between Triton-extracted apo B and tissue collagen and the lack of a significant correlation between buffer-extracted apo B and collagen content suggests that collagen is probably not responsible for apo B retention in the aortic intima.     

Zeitschriften

Ohne Zusammenfassung     

Buchbesprechungen

Ohne Zusammenfassung     

Resveratrol modulates human mammary epithelial cell O-acetyltransferase,sulfotransferase, and kinase activation of the heterocyclic amine carcinogen N-hydroxy-PhIP

Resveratrol (trans-3,4',5-trihydroxystilbene) is a natural antioxidant found in plants, such as grapes, that studies suggest has cancer chemopreventive activity. We investigated the effects of resveratrol on DNA binding via esterification reactions with 2-hydroxyamino-1-methyl-6-phenylimidazo[4,5-b]pyridine (N-OH-PhIP) - a metabolite of a mammary gland carcinogen present in cooked meats. Treatment of primary cultures of human mammary epithelial cells with 50 microM resveratrol led to a decrease in PhIP-DNA adducts ranging from 31 to 69%. Using substrate-specific assays and mammary gland tissue cytosols, resveratrol inhibited PhIP-DNA adduct formation by O-acetyltransferase and sulfotransferase catalysis. Cytosols from tumor tissue and breast reduction tissue were similarly affected. Resveratrol also suppressed O-acetyltransferase and sulfotransferase activities from the breast cancer cell lines MCF-7 and ZR-75-1. It was also observed that resveratrol stimulated ATP-dependent cytosolic activation of N-OH-PhIP in all human samples but not in mouse liver samples. In addition to resveratol's other preventive effects, the present data suggest that O-acetyltransferases and sulfotransferases may represent anti-oncogenic targets for resveratrol.     

Zur Differentialdiagnose der silikotischen Schwielen-Einschmelzung (Kasuistischer Beitrag)

Silicotic induration can be due to atypical mycobacteria or pathogenic bacteria: it is sometimes associated with abscess formation or superimposed on allergy, and can result from ischemic necrosis and melanoptysis. The aspects of differential diagnosis relevant to the evaluation of silicotic induration for legal and insurance purposes are discussed with reference to clinical observations and assessment in workers employed in manganese and coal mining. Particular emphasis is laid on an exact occupational history, the duration of exposure to dust, lung biopsy, and the result of autopsy.