7 beta-hydroperoxycholest-5-en-3 beta-ol, a component of human atherosclerotic lesions, is the primary cytotoxin of oxidized human low density lipoprotein.

Modification of low density lipoprotein (LDL) by free radical oxidation renders this molecular complex cytotoxic. Oxidized lipoproteins exist in vivo in atherosclerotic lesions and in the plasma of diabetic animals, suggesting that lipoprotein-induced tissue damage may occur in certain diseases. We undertook purification and identification of the major cytotoxin in oxidized LDL. The lipid extract from oxidized LDL was subjected to multiple HPLC separations, and the fractions were assayed for cytotoxicity. Mass spectrometry and nuclear magnetic resonance identified the purified toxin as 7 beta-hydroperoxycholest-5-en-3 beta-ol (7 beta-OOH-Chol). This molecule accounted for approximately 90% of the cytotoxicity of the lipids of oxidized LDL. We also found 7 beta-OOH-Chol in human atherosclerotic lesions from endarterectomy specimens obtained immediately after excision. These results are consistent with the hypothesis that the oxidized LDL present in lesions has the capacity to induce cell and tissue injury, leading to progression of the disease and the generation of the necrotic core of the lesion.

Pharmacokinetics and biochemical efficacy of pirmagrel, a thromboxane synthase inhibitor, in renal allograft recipients.

The effects of a 48-hour 0.5 mg/kg/hr infusion of the thromboxane synthase inhibitor pirmagrel were studied in 10 renal allograft recipients with cyclosporine nephrotoxicity. Plasma concentrations reached a mean steady-state plasma level of 1798 +/- 481 ng/ml. Biphasic, rapid elimination of pirmagrel was observed with a distribution half-life of 6.7 minutes and a terminal half-life of 73 minutes. Plasma clearance and the volume of distribution of the drug were 300 +/- 87 ml/hr/kg and 497 +/- 232 ml/kg, respectively. The pharmacodynamic effects of pirmagrel were marked by a mean 96% suppression of serum thromboxane B2 (TXB2), which coincided with a suppression of urinary excretion of TXB2, 2,3-dinor-TXB2, and 11-dehydro-TXB2 of 85% +/- 8%, 91% +/- 5%, and 89% +/- 9%, respectively. Urinary excretion of all thromboxane metabolites measured at the end of 1 week after termination of infusion was returned to the baseline. In conclusion, pirmagrel caused effective and sustained suppression of all thromboxane derived metabolites in plasma and urine during continuous infusion in kidney transplant patients receiving cyclosporine.

Lipid peroxidation as a possible cause of cataract.

The role of free-radical-induced lipid oxidation in the development of human lens opacity was studied. Physico-chemical parameters of the lens fiber membranes at different stages of cataract have been investigated. The deterioration of lens fiber plasma membranes structure preceding formation of large aggregates in lenticular matter, leading to lens opacity, was observed by electron microscopy. Initial stages of cataract were characterized by the accumulation of primary (diene conjugates, cetodienes) lipid peroxidation (LPO) products, while in the later stages there was a prevalence of end LPO fluorescent products. Reliable increase in oxiproducts of fatty acyl content of lenticular lipids was shown by direct gas chromatography technique obtaining fatty acid fluorine-substituted derivatives. The lens opacity degree is found to correlate with the level of the end LPO fluorescent product accumulation in its tissue, accompanied by SH group oxidation of crystallins due to decrease of reduced glutathione concentration in the lens. The injection of LPO products into the vitreous has been shown to induce cataract. It was concluded that peroxide damage of the lens fiber membranes may be the initiatory cause of cataract development.

[Metabolism of vitamin D in exogenous hypercorticism in rats]. / Obmen vitamina D pri ékzogennom giperkortitsizme u krys.

Short-term administration of hydrocortisone into rats (within 7 days) stimulated 1.25(OH)2D3 synthesis in kidney and led to accumulation of the metabolite in blood serum, small intestinal mucose and bones. After long-term administration of hydrocortisone within 28 days synthesis of 1.25(OH2D3) was decreased in kidney while the content of 24.25(OH)2D3 was was simultaneously increased. Concentration of labelled 1.25 (OH)2D3 and 24.25(OH)2D3 was distinctly decreased in small intestinal mucose and femur bones.

[Evidence of the oxidation of unsaturated fatty acids in cataracts]. / Dokazatel'stvo okisleniia nenasyshchennykh zhirnykh kislot pri katarakte.

Gas chromatography analysis with the use of an electron captured detector including preparation of the halogen-substituted derivatives of fatty acids is a useful tool for the detection of lipid peroxidation products both in vitro and in vivo. This technique was applied to determine the content of fatty acid oxy-derivatives in lipid samples of transparent and completely opaque human lenses. At the stage of mature cataract a significantly increased level of oxyproducts was observed in the lens lipid fraction. It was concluded that accumulation of polar oxygroups in the lipid bilayer of plasma membranes of lens fibres is a plausible cause of their damage in cataracts.

[Lipid fluorophores of the crystalline lens in cataracts]. / Lipidnye fluorofory khrustalika glaza pri katarakte.

Microcolumn liquid and column chromatography technique is conjunction with UV-spectrophotometry and spectrofluorescent analysis were used to study lipid peroxidation products accumulated in human lenses during cataract formation by means of chromatographic separation in regard to the molecular weight and polarity properties. Cataract is characterized by the appearance of certain substances changing UV-absorption lipid spectra in the region of 230 and 274 nm and having special fluorescence (excitation--320-370 nm), (emission--405-460 nm). The same changes were observed by ultrasoundinduced lipid peroxidation of model lipid samples. The accumulated lipid peroxidation products are concentrated in the same chromatographic fractions that are responsible for the change of UV-absorption and fluorescent spectra of lipids of cataractous lenses. It is the evidence of free radical lipid peroxidation products accumulation in human lenses at cataract formation. Along with the formation of diene and triene conjugates in the lens lipids, cataract is characterized by the formation of cetodienes and of low molecular weight lipid fluorescent products of fatty acids oxidation with low polarity due to the appearance of tetraene derivatives of polyunsaturated fatty acids. The particular features of mature cataract are an increased intensity of long-wave lipid fluorescence in the blue-green region (430-460 nm) of the spectrum, formation of high molecular weight fluorescent lipid peroxidation products with high polarity, and smooth decrease in absorbance in the region of 220-330 nm. During cataract formation products of deep lipid peroxidation resulting from radical phospholipids and fatty acids polymerisation are accumulated. It is supposed that lipid peroxidation is an initial phase of membrane desintegration and formation of HMW-proteins in cataract.

[Chromato-mass-spectral study of the secretion in the rabbit small intestine discharged in response to cholera and salmonella toxins]. / Khromato-mass-spektral'noe issledovanie sekreta tonkoi kishki krolikov, vydeliaemogo pod deistviem kholernogo i sal'monelleznogo toksinov.

A study was made of rabbit small intestine secretion induced by cholera and salmonellosis toxins. Application of electron impact mass-spectrometry and chemical ionization permitted identification of 9 and structure assignment for 14 out of 27 secretion components. The assay demonstrated the major part of the components to be the monosaccharides, glucose and galactose. Fatty acids, cholesterol and hydroxyacids were found to be present in negligible amounts. It was discovered that the action of the toxins primarily affected the metabolism of unsaturated fatty acids.

[Metabolism of 25-hydroxyvitamin D3 and its regulation in rats during hypokinesis]. / Metabolizm 25-oksivitamina D3 i ego reguliatsiia u krys pri gipokinezii.

The influence of short-(7 days) and long-term (28 days) hypokinesia on 25-hydroxyvitamin D3 metabolism was investigated in rats fed on a normal calcium (0.6%), normal phosphorus (0.6%), vitamin D-supplemented diet. The animals were given a single intraperitoneal dose of tritiated [26,27-3H]25(OH)D3 (200 pmol) eighteen hours before sacrifice. [3H]Labelled vitamin D3 metabolites were separated by high performance liquid chromatographic procedure, and their radioactivity levels in serum, kidney, intestinal mucosa and femoral bone were measured. Long-term hypokinesia resulted in decreased levels of [3H]1.25(OH)2D3 and increased levels of [3H]24.25(OH)2D3 in serum and kidney (3.15 +/- 0.62 vs. 4.33 +/- 0.41% and 5.34 +/- 0.69 vs. 3.76 +/- 0.29% for [3H]1.25(OH)2D3 and [3H]24.25(OH)2D3 in serum; 7.52 +/- 0.69 vs. 11.6 +/- 0.79% and 9.33 +/- 0.55 vs. 5.94 +/- 0.24% for those in kidney). The levels of [3H]1.25(OH)2D3 as well as of [3H] 24.25(OH)2D3 were decreased in intestinal mucosa and bone (21.5 +/- 1.46 vs. 30.1 +/- 3.04% and 7.30 +/- 0.58 vs. 9.18 +/- 0.78% for [3H]1.25(OH)2D3 and [3H]24.25(OH)2D3 in intestinal mucosa; 6.39 +/- 06.5 vs. 11.5 +/- 1.64% and 7.78 +/- 0.71 vs. 13.9 +/- 1.28% for those in bone). The data obtained suggest a suppressed synthesis of 1.25(OH)2D3 and enhanced production of 24.25(OH)2D3 in kidney as well as a diminished binding of 24.25(OH)2D3 in intestinal mucosa and bone in hypothetic rats. Possible causes of variations in biosynthesis of vitamin D3 active metabolites, and role of these variations in the disorders of calcium metabolism and bone state during hypokinesia are discussed.

[Metabolism of 3H-25-oxycholecalciferol in rats with experimental fracture of the femur]. / Obmen 3H-25-oksikholekal'tsiferola u krys s éksperimental'nym perelomom bedra.

At the third day after femur fracture concentration of 3H-25-hydroxycholecalciferol [3H-25(OH)D3], intraperitoneally administered into rats within 18 hrs before killing, was increased in kidney and small intestine mucosa by 25% and 60%, respectively, as well as incorporation of the label into 1,25(OH)2D3 in blood serum and small intestine mucosa was increased by 50% and 70%, respectively, as compared with intact controls. Binding of 3H-25(OH)D3 was increased 2-3-fold in diaphyses and epiphyses of impaired bones within 3 and 10 days after the fracture. Similar, but less distinct accumulation of 3H-25(OH)D3 was observed in unimpaired femur of rats with the bone fracture. Incorporation of the label into 1,25(OH)2D3 and 24,25(OH)2D3 was increased 1.5-2-fold in epiphyses of the impaired bone as well as in epiphyses and diaphyses of intact femur of rats with the bone fracture at all the periods studied (3, 10, 28 days after the fracture).

[Phospholipid composition of mucous membrane tissue in the gastrointestinal tract of rabbits in simulated Salmonella infections]. / Sostav fosfolipidov tkani slizistoi obolochki zheludochno-kishechnogo trakta krolikov pri modelirovanii sal'monelleznoi infektsii.

The paper deals with the phospholipid composition in the mucosa tissue of different areas of gastrointestinal tract and in membranes of the villous margin of small intestine enterocytes under conditions of experimental salmonellosis infection. A decreased relative content of cardiolipin is observed in all periods of the infection process in the stomach mucosal tissue and in the period of the disease height and convalescence--in the sigmoid colon. Phosphatidyl choline appears in the tissue of duodenum and jejunum during the height of the infection process. An increase in a relative content of lysophosphatidyl choline and phosphatidyl serine and a decrease in that of phosphatidyl ethanolamine are revealed in membranes of enterocyte villous margin when modelling the diarrhea process by the intraperitoneal administration of the lipopolysaccharide complex of salmonellas. The found changes in the composition of phospholipids in the mucous membrane tissue and membranes of the enterocytes villous margin are supposed to reflect alterations in the functional state of the intestine barrier and play a definite role in development of the diarrhea syndrome.

[Experimental study of the development of the diarrhea syndrome using gas-liquid chromatography]. / Issledovanie dinamiki razvitiia diareinogo sindroma v éksperimente metodom gazozhidkostnoi khromatografii.

Gas liquid chromatography was made use of to examine the time course of elimination of low-molecular weight organic components with the diarrhea fluid under the effect of cholerae and salmonellosis toxins. The diarrhea fluid was shown to contain a great number of low-molecular weight metabolites some of which occur in noticeable concentrations. As a result of the action of the bacterial toxins. there appear metabolic disturbances that might be distributed into 4 types with regard to the time course of their development. The method under consideration enables the detection of disorders that occur within the latent period.

[Study of the pharmacokinetics of phosphemide in rats with the use of physico-chemical methods]. / Izuchenie farmakokinetiki fosfemida u krys s pomoshch'iu fiziko-khimicheskikh metodov

A study on the passage of phosphemide with urine and distribution of the drug over the organs and tissues of intact (without fumour) rats and those with sarcoma-45 showed the bulk of unchanged drug to be excreted together with the urine during the first 3-4 hours following its intravenous and intraperitoneal administration. In rats with sarcoma-45 phosphamide is passed with urine in a somewhat greater amount than in the intact animals. With intravenous application the rate of the drug elimination in intact rats and in the ones with carcoma-45 is virtually the same, being somewhat lower with intraperitoneal injection of phosphemide.