[Apolipoprotein A-IV and transportation of cholesterol from smooth muscle cells in experimental hyperlipidemia].

The effects of apolipoprotein (apo) A-IV and apoA-IV/phosphatidylcholine (PC) liposome on cholesterol efflux from the smooth muscle cells originating from the aorta of hypercholesterolemic rabbit model and control rabbits, and on the activation of lecithin cholesterol acyltransferase (LCAT) were studied respectively. Both apoA-IV/PC and apoA-I/PC liposomes have similar efficiency as the HDL's, i.e.

DNA adducts in cervical tissue of smokers and non-smokers.

Cervical biopsy samples were taken from 40 women, aged between 31 and 72, undergoing hysterectomies. Twenty-two of the women were smokers, four were ex-smokers and 14 were non-smokers. DNA was isolated and analysed using 32P-postlabelling, after butanol extraction or nuclease P1 digestion enhancement of the adducts.

Influence of dietary fat on DNA binding by 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) in the mouse liver.

Female BALB/c mice were fed either a low (1%)-fat or one of three high-fat diets (containing an additional 25% (w/w) beef fat, hydrogenated vegetable oil or non-hydrogenated vegetable oil) for 4 wk. They were then orally treated with 10 mg 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx)/kg body weight and killed 6 hr later. Consumption of the hydrogenated vegetable oil was accompanied by increased DNA adduct formation in mice.

Evidence for the involvement of a bis-diol-epoxide in the metabolic activation of dibenz[a,h]anthracene to DNA-binding species in mouse skin.

Dibenz[a,h]anthracene (DB[a,h]A) and its microsomal metabolites, trans-3,4-dihydro-3,4-dihydroxydibenz[a,h]anthracene (DBA-3,4-diol), trans,trans-3,4:8,9-tetrahydro-3,4:8,9-tetrahydroxydibenz[a,h]anth racene, trans,trans-3,4:10,11-tetrahydro-3,4:10,11-tetrahydroxydibenz[a,h] - anthracene (DBA-3,4,10,11-bis-diol) and trans,trans-3,4:12,13-tetrahydro-3,4:12,13- tetrahydroxydibenz[a,h]anthracene were each applied topically to mouse skin and the epidermal DNA isolated 24 h later. 32P-postlabeling analysis of each of the DNA samples was performed. DNA from mice treated with DB[a,h]A produced an adduct map on TLC consisting of one major and three minor adduct spots.

Detection and characterization by 32P-postlabelling of DNA adducts induced by a Fenton-type oxygen radical-generating system.

Reactive oxygen species can give rise to numerous modifications of DNA. We have investigated the formation of such modifications using the nuclease P1 digestion method of the 32P-postlabelling procedure for the detection of DNA damage. Analysis of DNA that had been treated with a Fenton-type system of copper (or iron) ions and H2O2 resulted in the detection of up to ten discrete 32P-labelled spots, displaying chromatographic characteristics similar to aromatic adducts, on PEI-cellulose TLC.

HDL and apolipoprotein A1 (apo A1). Their effects on retardation of lipid deposition in aortic intima.

The aim of this study is to clarify whether apo A1 displays a similar role as that of HDL in preventing the development of experimental atherosclerosis. Results were obtained from 4 groups of experiments. (1) Result from 4 successive experiments of tree shrews indicated that high serum HDL level is the main factor in preventing the development of experimental atherosclerosis; (2) Results from 4 successive experiments in rabbits showed that both HDL and apo A1 were able to decrease the extent of lipid deposition and atheromatous lesion developed in the aortic intima; (3) Apo A1 also inhibited the number of monocytes/macrophages infiltrated in aortic intima at the initial stage of fatty streak formation; (4) Similar as HDL, apo A1 phospholipid liposomes promoted markedly the clearance ability of smooth muscle cells on intracellular cholesterol.

The metabolic activation of dibenz[a,h]anthracene in mouse skin examined by 32P-postlabelling: minor contribution of the 3,4-diol 1,2-oxides to DNA binding.

Dibenz[a,h]anthracene (DB[a,h]A) and the related 3,4-diol and anti- and syn-3,4-diol 1,2-oxides were applied to the shaved dorsal skin of groups of four C57Bl/CB1 mice. Twenty-four hours later the mice were killed, DNA isolated from the treated skin, hydrolysed and examined for the presence of aromatic adducts using the nuclease P1 modification of the 32P-postlabelling technique. Autoradiography of the maps obtained by chromatography on polyethyleneimine-cellulose plates showed that six DNA adduct spots that were derived from DB[a,h]A were also present in the DNA of skin treated with the DBA 3,4-diol and that, whilst four of these adduct spots were also seen in maps prepared from the DNA of skin treated with the anti-3,4-diol-1,2-oxide, they were not present in DNA from skin to which the syn-isomer had been applied.

Tissue distribution of DNA adducts in CDF1 mice fed 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ).

Male and female CDF1 mice were administered a single oral dose of 3 mumol of the food mutagens 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) or 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) and killed 24 h later. DNA was isolated from the livers, lungs, kidneys, colon and forestomach and analysed by 32P-postlabelling for the presence of IQ and MeIQ adducts. Several adduct-enrichment procedures were investigated, including ATP-deficient labelling conditions, butanol extraction and nuclease P1 digestion, and only the ATP-deficient procedure was found to produce the same adduct pattern on polyethyleneimine--cellulose TLC as the standard procedure.

High density lipoproteins and prevention of experimental atherosclerosis with special reference to tree shrews.

According to data obtained from epidemiological and experimental survey, serum HDL level is known to be correlated conversely with the incidence of atherosclerosis. Experimental data collected in this article explained part of its mechanism, which is described in four parts as follows: 1. The result of 3 successive experiments on experimental atherosclerosis in tree shrews (total of 96 animals available including 40 as the controls) showed that the serum HDL level had been kept persistantly to 69-88% of the total serum lipoproteins even after a high cholesterol intake for 32 weeks.

Characterization of HDL binding sites and its ligand in cultured smooth muscle cells of rabbit's aorta.

Cultured smooth muscle cells of rabbit aorta were studied by 125I labelled rabbit HDL3. Saturation curves, measured at 4 C, showed the presence of two different components: the low-affinity non-saturable binding portion and the high-affinity binding portion (Kd about 5.6 x 10(-8) mol/L and Bmax about 0.