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PubMedDate not supplied

[The effect of lipid peroxidation on the lipid and phospholipid composition of mitochondrial membranes during thermal incubation].

Alterations in the content of lipids and phospholipids were studied in rat liver mitochondrial membranes after long-term heating at 37 degrees, pH 7.4, using FeSO4-ascorbate as inductors of lipid peroxidation. Under these conditions, activation of lipid peroxidation in mitochondrial membranes led to a marked increase in the rate of hydrolysis of phosphatidylethanolamine and lysophosphatidylethanolamine, to elevated synthesis of phosphatidylserine, sphingomyelin, phosphatidic and lysophosphatidic acids, diglycerides and cholesterol esters as well as to inhibit hydrolysis of phosphatidylcholine, cardiolipin and their lyso-derivatives.

Animals↗
PubMedDate not supplied

[A thermodynamic analysis of oxidative inactivation of influenza virus and lipid peroxidation of viral envelope lipids].

The "activation energy" values for virus inactivation (22.2 kcal/mol) calculated using Arrenius formula and the levels of accumulation of the final product of lipid peroxidation, fluorescent pigment (21.2 kcal/mol), in virus envelopes were found to be in good correlation for purified influenza A/PR8/34 virus suspensions stored at temperatures from 6 to 37 degrees C. A "lipid" mechanism of inactivation of enveloped viruses is proposed, permitting, together with the "nucleic" and "protein" mechanisms, a satisfactory interpretation of the relationship between the stability of viral material and the medium composition, lipid composition of virus envelopes, and other factors.

Fluorescent Dyes↗
PubMedDate not supplied

[Change in lipid composition and lipid peroxidation rate in brain tissue under conditions of thymic hormone deficiency].

Experiments on mature male rats have shown that 3 and 6 months after removal of the brain thymus, the level of total lipids in all cell centrifugate fractions (homogenate, supramitochondrial and mitochondrial fractions), which was followed by the higher rate of lipid peroxidation and the lower activity of cellular compartments, the spectrum imbalance of lipid fractions with predominant increases in the levels of phospholipids and free cholesterol. It is suggested that these changes make a contribution to the dysfunction of brain structures and participate in regulatory processes in thymectomy.

Animals↗
PubMedDate not supplied

[The characteristics of tissue lipid peroxidation in the internal organs and the lipid metabolic indices of the blood plasma in a low geomagnetic field].

It was found in experiments on guinea-pigs and white rats that 100-time weakened magnetic field of the earth considerably increased the activity of peroxide oxidation of lipids (POL) in tissues of inner organs. In the lungs, liver, kidneys, small intestine under the influence of hypogeomagnetic field (HGMF) we have observed reduction of ferment antioxidizing activity and of non-ferment mechanisms in the heart. The process is accompanied by reduction of cholesterol, phospholipids and triglycerides in guinea-pigs and increase of this indices in white rats after 5-day-long stay of animals in the hypogeomagnetic chamber. The data of experiments on white rats underlie a conclusion that the 5-day-long influence of HGMF promotes the change of the carbohydrate metabolism for lipid metabolism. The reaction of guinea-pigs on the stay under the weakened magnetic field of the earth displays in reduction of the level of lipid metabolism indices in the blood serum.

Animals↗
PubMed1977

[Morphological change of lipids in the vaginal epithelium after intrauterine fetal death (lipid test)].

The authors studied the lipid content of the vaginal epithelium of gravida in whom intrauterine fetal death had occurred. Fifteen gravida in the 6th to 10th month of gestation were examined and an unusual, inconsistent with the respective gestation term increase in the intra- and extra-cellular lipid content of the vaginal epithelium demonstrated. This is related to a decrease in the amount of estrogen hormones secreted by the placenta. A cytochemical 'lipid test' based on the above findings has been developed by the authors for the diagnosis of intrauterine fetal death during the second half of pregnancy.

Adult↗
PubMed1997

[The indices of lipid metabolism and of lipid peroxidation in acute intestinal obstruction and the administration of plasma substitute solutions].

The influence of the intravenously infusion of plasma substitute solution from the whey on the some indices of the lipid metabolism and the lipid peroxidation were studied in the experiments on the model of ileus. Resive data indicate the considerable alteration of the lipid peroxidation under ileus. The infusion therapy of the solution from the whey decreased the level of lipoperoxides and malondialdehyde in the liver and reduced the level of beta-lipoproteins in serum of blood.

Acute Disease↗
PubMed1997

[Effects of essential oil on lipid peroxidation and lipid metabolism in patients with chronic bronchitis].

Natural concentrations of some essential oils were examined for effects on the system lipid peroxidation-antioxidant defense and lipid metabolism in 150 patients with chronic bronchitis. Lowering of plasm levels of dienic conjugates and ketons, activation of catalase in red cells characteristic of antioxidant effect were observed in exposure to essential oils of rosemary, basil, fir, eucalyptus. Lavender essential oil promotes normalization of the level of total lipids, ratio of total cholesterol to its alpha-fraction.

Adult↗
PubMed2005

Serum lipids, lipid-lowering drugs, and the risk of breast cancer.

BACKGROUND: Experimental evidence suggests that statins protect against breast carcinogenesis by interrupting cell cycle progression and promoting apoptosis. Evidence in humans is limited and inconsistent. The relation between serum cholesterol levels and breast cancer risk is itself unclear; because cholesterol is the precursor to sex steroid hormones, higher levels could plausibly increase risk. METHODS: The associations of statins, general lipid-lowering drugs, and reported cholesterol levels with breast cancer risk were assessed in the Nurses' Health Study, with 6 to 12 years of follow-up. A total of 79,994 women aged 42 to 69 years and free of cancer were followed prospectively for up to 12 years. Current statin use, including duration, was assessed retrospectively in 2000 in 75,828 women. Self-reported serum cholesterol level was assessed prospectively between 1990 and 2000 in 71,921 women. RESULTS: Overall, we documented 3177 incident cases of invasive breast cancer. Compared with nonusers, current lipid-lowering drug users experienced similar breast cancer risk (multivariate relative risk [RR], 0.99; 95% confidence interval [CI], 0.86-1.13). Current use of statins also was not significantly associated with breast cancer risk (RR, 0.91; 95% CI, 0.76-1.08). Associations by duration of current use were similarly null. Self-reported serum cholesterol levels were not associated with breast cancer risk in postmenopausal women with levels of 240 mg/dL or higher (> or = 6.22 mmol/L) compared with less than 180 mg/dL (< 4.66 mmol/L) (RR, 1.04; 95% CI, 0.91-1.17). CONCLUSION: Overall, these data suggest that serum cholesterol levels and the use of lipid-lowering drugs in general and of statins in particular are not substantially associated with breast cancer risk.

Adult↗
PubMed1988

Biological and cultural sources of familial resemblance in plasma lipids: a comparison between North America and Israel--the Lipid Research Clinics Program.

Heterogeneity in determinants of familial resemblance of lipid and lipoprotein levels between populations in North America and Israel was investigated using path analysis. A common protocol, identical measurement techniques, and the same statistical procedures were used in the two samples. Both genetic (h2) and cultural (c2) determinants of inheritance were significant for all lipid variables in the two studies. Genetic and cultural heritability of total cholesterol (h2 = 0.61, c2 = 0.02), low-density lipoprotein cholesterol (h2 = 0.59, c2 = 0.02), and high-density lipoprotein cholesterol (h2 = 0.55, c2 = 0.06) did not differ significantly between North America and Israel, while there was a significant difference for triglyceride (h2 = 0.41, c2 = 0.07 in North America; h2 = 0.61, c2 = 0.05 in Israel). Secondary parameters of the path model describing intrafamilial environmental relationships differed between the two countries. In particular, there was a higher correlation between marital environments in Israel for all traits except triglyceride, and a larger effect of father's environment on offspring's environment in Israel for all traits. Within both populations, variation of plasma lipids and lipoproteins was mostly explained by genetic factors and random unmeasured environmental factors. The contribution of common family environment was found to be small, though statistically significant. This is probably due to homogeneity of the distribution of familial environmental determinants within both countries.

Cholesterol↗
PubMed1995

[Effect of changes in the lipid composition on the plasma membrane of Saccharomyces cerevisiae through mutation of the phase transition and mixing behavior of the lipid fraction].

Mutation of Saccharomyces cerevisiae leads to an alteration of the size and surface structure of the mutant cell. These phenomena are correlated with change in the lipid composition and hence membrane fluidity of the plasma membranes. Such alterations are in the fatty acyl constituents of phospholipids and glycolipids and include changes in the saturation or length of fatty acyl chains. Simultaneously, the "melting point" of phospholipid fractions, i.e. the temperature of the ordered-disordered phase transition and mixing behavior, changed. Consequently calorimetry on isolated phospholipid fractions extracted from plasma membranes is a useful analytical method to demonstrate directly such phase transitions and change in the mixing behavior of the cellular lipid fractions in connection with mutation. A correlation between the alteration of the lipid composition in the plasma membrane of strains of S. cerevisiae S 288 and its mutant VY 1160 is discussed.

Calorimetry↗
PubMed1999

Fast laser-induced solute release from liposomes sensitized with photochromic lipid: effects of temperature, lipid host, and sensitizer concentration.

Liposomes of gel-phase phospholipid have been prepared containing a photochromic lipid sensitizer. A fast UV laser pulse isomerizes the sensitizer destabilizing the lipid bilayer structure and causing release of trapped solute. The kinetics of solute release have been investigated as a function of host lipid chain length, sensitizer concentration, and temperature, and the limits of liposome stability have been established. At low concentrations of sensitizer, pulsed laser irradiation induces some solute release when continuous UV illumination is ineffective. Although rates of solute release usually increase with temperature, at low sensitizer concentration in a rigid host, leakage at first increases but then decreases rapidly above a threshold temperature. The results presented are relevant to the design of photostimulated drug delivery systems and to potential applications of photosensitive liposomes as caging agents for biological effectors.

Dose-Response Relationship, Radiation↗
PubMedDate not supplied

The effects of cyclic imides on lipid absorption from the intestine and on bile lipids and bile acids of Sprague Dawley rats.

The cyclic imides, o-(N-phthalimido)acetophenone, 2,3-dihydrophthazine-1,4-dione and N(4-methyl phenyl)diphenimide, were evaluated for their effects on bile lipids, bile acids, small intestinal absorption of cholesterol and cholic acid and liver and small intestinal enzyme activities involved in lipid metabolism. The agent at 20 mg/kg/day orally elevated rat bile excretion of lipids, e.g. cholesterol and phospholipids, and increased the bile flow rate. These agents altered the composition of the bile acids, but there was no significant increase in lithocholic acid which is most lithogenic in rats. The three agents did decrease cholesterol and cholic acid absorption from isolated in situ intestinal duodenum loops in the presence of drug. Hepatic and small intestinal mucosa enzyme activities, e.g. ATP-dependent citrate lyase, acyl CoA cholesterol acyl transferase, cholesterol-7-alpha hydroxylase, sn-glycerol-3-phosphate acyl transferase, phosphatidylate phosphohydrolase, and lipoprotein lipase were reduced. However, the cyclic imides did not accelerate HMG-CoA reductase activity, the regulatory enzyme for cholesterol synthesis, in a manner which would accelerate biliary cholesterol excretion. There was no evidence of hepatic cell damage afforded by the drugs based on clinical chemistry values which would induce alterations in bile acid concentrations after treatment of the rat.

Animals↗
PubMedDate not supplied

The nomenclature and conformational analysis of lipids and lipid analogues.

Lipids form an essential part of the biomembrane and it is of paramount importance to study their conformational aspects. It is found that the present methods of nomenclature for lipids are totally inadequate for describing these diverse amphipathic molecules. Further the existing methods are incompatible in terms of assignment of the absolute configuration. A systematic method for the naming of lipids which is rationally extendible to a wide class of amphipaths is described. The conformational features of the natural glycerolipids as well as a synthetic amphipath containing a glutamic acid moiety known to undergo interesting phase transitions, have been examined in detail using the framework of the current nomenclature system. The implications of the conformational flexibility of these molecules on assemblies of these systems is touched upon.

Membrane Lipids↗
PubMed1982

Comparative evaluation of red cell-labeling parameters of three lipid-soluble- 111In-chelates: effect of lipid solubility on membrane incorporation and stability constant on transchelation.

A rabbit red cell model was used to determine the cell labeling properties of three lipid-soluble 111In-complexes: 111In-oxine, 111In-acetylacetone, and 111In-tropolone. Partition coefficients (olive oil/buffer) were measured to determine the lipid solubility and were 3.54, 7.93, and 18.18 for 111In-oxine, 111In-acetylacetone, and 111In-tropolone respectively. The effect of the concentration of these three chelating agents on labeling efficiencies was studied. The factors influencing the labeling efficiencies of these complexes such as cell density, time of incubation, influence of temperature, pH, effect of plasma proteins, and citrate ion concentration in the cell-labeling medium were studied. Labeling yields as high as 95.15 +/- 4.15% were achieved with 111In-tropolone after a 10-min incubation at 37 degrees C. The optimum pH for cell labeling was 6.5. Excess citrate ion (greater than 3.02 mg/ml) and small amounts of plasma proteins (greater than 10 microliter/ml) decreased the labeling efficiencies in all three cases. Distribution of these 111In-complexes in membrane, membrane fragments, and hemoglobin was studied after hemolysis. In spite of the higher lipid solubility of 111In-tropolone, the transchelation capacity appears to be similar to that of 111In-oxine. 111In-acetylacetone had the highest transchelation capacity.

Animals↗
PubMed1989

Lipid aspiration pneumonia due to gastroesophageal reflux. A complication of nasogastric lipid feedings.

The development of lipid aspiration pneumonia after chronic nasopharyngeal installation of mineral oil was first described in 1925 by Laughlin. Since that time this entity has been well recognized and numerous substances have been identified or implicated as the aspirated material. The classic radiographic appearance of severe chronic lipid aspiration pneumonia has been described as consisting of intense perihilar infiltrates. However, the radiographic findings are more often non-specific and usually consist of varying degrees of diffuse interstitial infiltrates that tend to be more prominent in the perihilar regions and the right lung. We are reporting a case of biopsy-proven lipid aspiration pneumonia in an infant with known gastro-esophageal reflux (GER) who had medium-chain triglyceride oil administered via nasogastric tube. Serial roentgenograms demonstrated a changing pulmonary pattern from diffuse bilateral interstitial infiltrates initially to a diffuse alveolar pattern at the time of the lung biopsy. Modern medicine has developed new methods for providing nourishment to sick newborns and infants to improve their nutritional status and help them to grow. One such method involves the administration of medium-chain triglycerides (MCT oil) into the GI tract via a nasogastric or nasoenteral tube. The purpose of this report is to describe a significant complication of this method of providing nutrition to an infant with gastroesophageal reflux (GER) and the diagnostic dilemma it presented.

Dietary Fats↗
PubMed1975

Hepatoma, host liver, and normal rat liver lipids: distribution of isomeric monoene fatty acids in individual lipid classes.

Monoenoic acid fractions were isolated from phosphatidycholine, phosphatidylethanolamine, triglycerides, and cholesteryl esters of hepatoma 7288CTC, host liver, and normal liver from animals maintained on chow and fat free diets. Hexadecanoate (16:1), octadecenoate (18:1), and eisosenoate (20:1) fractions were analyzed quantitatively for their isomeric composition. The fat free diet had little or no effect relative to the chow diet on the isomeric composition of 16:1, 18:1, and 20:1 from any lipid class in either heptoma, host liver, or normal liver. Host livers were reduced in palmitoleic acid, and oleic and eicos-11-enoic acids were increased relative to normal liver. The 16:1 fraction from triglyceride of normal liver, host liver, and hepatoma contained 90, 80, and 75% palmitoleic acid, respectively. The 20:1 fraction from triglycerides of normal liver, host liver, and hepatoma contained ca. 55, 70, and 60% eicos-11-enoic acid, respectively, with the remainder consisting of eicos-13-enoic acid. The proportion of vaccenic acid in the 18:1 fraction was 60, 50, 20, and 25% for phosphatidylethanolamine, phosphatidylcholine, triglycerides, and cholesteryl esters, respectively, with oleic acid making up the balance. In contrast, all hepatoma lipid classes exhibited the same proportion of oleic (70%) and vaccenic (30%) acids. These data appear to be the first to demonstrate lipid class specificity for isomeric octadecenoic acids in normal liver and the loss of this specificity in a neoplasm.

Carcinoma, Hepatocellular↗
PubMed1983

Role of membrane lipids in the immunological killing of tumor cells: I. Target cell lipids.

The metabolic and physical properties of tumor cells that are associated with their ability to resist or escape from immune attack have been investigated. The susceptibility of P815 murine mastocytoma cells to immune killing can be modulated. Culturing the cells with adriamycin or with hydrocortisone increases or decreases, respectively, the sensitivity of the cells to killing by antibody (Ab) plus complement (C); in addition, culturing the cells with mitomycin C or hydrocortisone increases or decreases, respectively, the sensitivity of the cells to killing by cytotoxic T lymphocytes (CTL). The susceptibility of the cells to Ab-C killing correlates with the ability of the cells to synthesize complex cellular lipids, but not DNA, RNA, protein, or carbohydrate. Further, tumor cells rendered sensitive to Ab-C killing by adriamycin are decreased in total lipid content and in their cholesterol/phospholipid mole ratio; hydrocortisone-treated resistant cells showed the opposite effects. The ability of tumor cells to resist CTL killing did not correlate with their total cellular lipid synthesis, but did correlate with the synthesis and composition of specific cellular phospholipids. In addition, tumor cells increased in sensitivity to Ab-C killing exhibited an increase in cell surface membrane fluidity, whereas cells increased in susceptibility to CTL attack showed an increase in their net negative cell surface charge density. These data show certain unique chemical and physical properties of tumor cells to be of fundamental importance for their ability to resist either humoral or cell-mediated immunologic attack; modulation of one or another of these cellular properties results in a change in the cells' susceptibility to immune killing by antibody plus C or by cytotoxic T lymphocytes.

Animals↗
PubMed1981

Serum lipids and lipoproteins in patients with gallstone (relationship between serum lipids and types of stones in roentgenograms and sectional views).

Serum lipids and lipoproteins of gallstone patients were analyzed and compared with lithogenesity of bile and type of stones by roentgenographic and cross-sectional views. Incidences of hypercholesterolemia and triglyceridemia were higher in patients with radiolucent gallstones than with radiopaque stones. Furthermore, an incidence of hypertriglyceridemia was higher in patients with radiolucent solitary stones than with radiolucent multiple stones. The degrees of hyperlipidemia were moderate. Lipoprotein disc electrophoresis of sera of hyperlipidemic patients revealed type IIa, IIb or IV. More solitary and less multiple stones were seen in the hyperlipoproteinemic patients than normolipoproteinemic. Multiple stones with normolipoproteinemia were more accompanied by unsaturated bile (lithogenic index less than 1.0) than those with hyperlipoproteinemia and solitary stones with hyperlipoproteinemia or without. Solitary stones obtained surgically from normolipoproteinemic patients were pure cholesterol, combination or mixed stones, while multiple stones not including pure cholesterol and combination stones with pure cholesterol in the center. Solitary stones in hyperlipoproteinemic patients proved mostly either pure cholesterol or combination stones with pure cholesterol ins the center, while multiple stones containing all types of stones inclusive of a small number of other miscellaneous stones except cholesterol stones. Collectively more mixed and other miscellaneous stones except cholesterol stones, and less pure cholesterol and combination stones with pure cholesterol in the center were shown in normolipidemic patients, and vice versa in hyperlipoproteinemic patients. These results suggested serum lipids and lipoproteins being closely related to the initial precipitation, aggregation of cholesterol crystals and development of cholesterol gallstones through lipid metabolism of the whole body.

Adolescent↗