Nanomolar concentrations of prostaglandin E1 induce changes in the surface organization of high-density lipoproteins.

Incubation of high-density lipoproteins (HDL) with small amounts of the prostaglandin E1 (PGE1) results in mobilization of the spin-label 5-doxylstearic acid incorporated into the HDL surface monolayer as well as in decreased binding of apoprotein A1 antibodies to the HDL surface. These effects are manifested at strikingly low PGE1 concentrations, corresponding to one prostaglandin molecule per 10(2)-10(3) lipoprotein particles. At the same time, the flotation properties of HDL are not changed in the presence of PGE1. The data are interpreted on the basis of a nonequilibrium model proposed earlier for prostaglandin-lipoprotein interactions (Bergelson, L. D., et al. (1987) Biochim. Biophys. Acta 921, 182-190).

[Comparison between seasonal changes in lipid indicators in patients with post-infarction cardiosclerosis and arterial hypertension in Ashkhabad and Moscow]. / Sravnenie sezonnykh kolebanii lipidnykh pokazatelei u bol'nykh postinfarktnym kardiosklerozom i arterial'noi gipertoniei v Ashkhabade i Moskve.

The study was undertaken to examine 190 males, aged 30-60 years who were divided into 4 groups: (1) patients with essential hypertension; (2) those with postinfarction cardiosclerosis; (3) those with postinfarction cardiosclerosis and essential hypertension; (4) healthy individuals. The levels of apolipoproteins B and A1 and circulating immune complex cholesterol were examined in the cold (winter) and hot (summer) seasons in the areas of arid (Ashkhabad) and temperate (Moscow) climate. The major apo-proteins were determined by enzyme uncompetitive immunoassay. Cholesterol levels in the immune complexes were measured by the method developed at the Institute of Experimental Cardiology, All-Union Cardiology Research Center, USSR Academy of Medical Sciences. The Moscow examinees were found to have more profound changes in the lipid spectrum than the Ashkhabad ones. In both climatic zones, the level of the major apo-proteins and their ratio were unaffected by seasonal variations.

[Plasma apolipoproteins B and AI in healthy individuals and patients with coronary atherosclerosis in a male population from Lithuania]. / Issledovanie apolipoproteidov B i AI v plazme krovi u zdarovykh i bol'nikh aterosklerozom koronarnykh arterii muzhchin v populiatsii Litvy.

The paper discusses the results from a study into apolipoproteins B (apo-B) and AI (apo-AI) and apoB/apo-AI ratios in the blood of 188 healthy donors and 122 male patients with coronary atherosclerosis. Atherosclerotic lesions were coronary angiographically documented. The study was performed (in two age groups of patients: 1) those under 45 years and 2) those over 45 years. A relationship was examined between the levels of apolipoproteins and the lesion of one, two, three or more coronary arteries in the two age groups. The studies indicate that there are various mechanisms responsible for the pathogenesis of atherosclerosis in the age groups in question. It is concluded that the younger a patient is, the higher probability that elevated blood apo-B levels are essential in the pathogenesis of coronary atherosclerosis is. Determination of plasma apo-B and apo-AI levels and apo-B/apo-AI ratios enables a potential number of diseased coronary arteries to be predicted.

[An evaluation of the efficacy of antiatherosclerotic agents based on a study of the peripheral blood monocytes]. / Otsenka éffektivnosti protivoateroskleroticheskikh sredstv na osnove issledovaniia monotsitov perifericheskoi krovi.

Examination of the effect of calcium antagonists on the functional activity of monocytes revealed the possibility of using these cells as an object for testing antiatherosclerotic agents. The functional activity of monocytes was evaluated by their capacity of producing thromboxane B2 and by the cellular content of cyclic AMP. It is suggested that calcium antagonists verapamil and niphedipin, in particular, are potential antiatherosclerotic agents.

[The effect of propranolol on the apoprotein spectrum of the blood plasma in patients with ischemic heart disease]. / Vliianie propranolola na spektr apoproteinov plazmy krovi bol'nykh ishemicheskoi bolezn'iu serdtsa.

The authors studied the effect of anaprilin monotherapy (dose: 160-200 mg/daily for 10 months) on the level of atherogenic apolipoproteins (apo A, apo B) and fractions of plasma cholesterol in 34 patients with ischemic heart disease, stable exertion angina pectoris (class 2-3). It was established that changes in the plasma lipid and apoprotein spectrum result in an increase of apo B, decrease of apo 1, increase of apo B/apo A1, decrease of high-density lipoprotein cholesterol (HDLCS) and a different dynamics of HDLCS/apo A1. The established changes in the lipid metabolism are of atherogenic character.

Enzyme-linked immunoreceptor assay of low-density-lipoprotein receptors.

A new modification of enzyme immunoassay-enzyme-linked-immunoreceptor assay (ELIRA) was used to study low-density lipoprotein (LDL) binding by cultured human skin fibroblasts. Time-course and concentration curves obtained by this method were typical of LDL binding by cultured fibroblasts. According to ELIRA, fibroblasts bound native LDL 10-20 times more effectively than reductively methylated LDL or native LDL in the presence of heparin. Receptor-specific Km and maximum binding capacity calculated from these data were 5.4 micrograms/ml and 177.5 ng/mg of cell protein, respectively. Receptor-specific Km and maximum binding capacity for surface 125I-LDL binding measured in the same experiment were 11.0 micrograms/ml and 138.0 ng/mg of cell protein. Incubation of cells with isolated LDL or with unfractionated serum containing the same amount of apoB yielded similar concentration curves for lipoprotein binding. These data indicate that the ELIRA can be used for investigation of receptor-mediated lipoprotein binding without purification of lipoproteins.