Amniotic fluid total lipids, lipid phosphorus, phospholipids and cholesterol in diabetic women

Total lipids, lipid phosphorus, phospholipids and cholesterol were determined in amniotic fluid of 36 normals and 6 mothers with diabetes. Total lipids, lipid phosphorus and phospholipids are significantly decreased in diabetic cases and the decrement was more pronounced in the cases with stillbirth or intrapartum deaths or infants with respiratory distress syndrome. Total cholesterol was significantly decreased in the same cases mentioned above. However, in spite of this decrease the ratio of total cholesterol to total lipids was constant except in cases with prolonged intrauterine fetal death where it was increased.     

Effects of serum,its protein and lipid extracts,and commercial serum proteins and lipid on the isolated frog heart

Summary This study investigates the inotropic effects of serum, its protein and lipid extracts, and commercial serum proteins and lipid on the isolated, spontaneously-beating heart and superfused, hypodynamic ventricle of the frog. Serum taken from either man, horse, calf, frog, or rabbit evoked marked positive inotropic responses which were unaffected by cholinergic, serotonergic, and adrenergic receptor antagonists. Dialysed serum (dialisand) and void volume fractions from Sephadex G200–120 columns corresponding to large molecular weight constituents evoked marked positive inotropic responses. When serum was separated into fractions containing either proteins or lipids/lipoproteins by high-density ultracentrifugation or activated charcoal, both extracts evoked marked positive inotropic responses. Commerical serum globulins and serum containing a high proportion of immunoglobulins elicited large increases in contractile force, whereas serum albumin evoked a negative inotropic effect. Serum which was either boiled and/or treated with chymotrypsin to denature proteins also caused a marked increase in isometric twitch tension in the frog heart. Similar inotropic response was obtained with fractions of boiled serum eluted on columns of Sephadex G200–120. These fractions corresponded to molecular weight in the region of 60–70 kDa. However, the inotropic effect of boiled serum was abolished following pretreatment with lipase. Superfusion of frog hearts with commercial cardiolipin resulted in marked dose-dependent increases in contractile force. The results demonstrate the presence of at least two large molecular weight cardioactive principles in serum. These substances are comparable in size to constituents of serum proteins (e.g., globulins and immuno-globulins) and serum lipids/lipoproteins (e.g., cardiolipin) and may serve as physiological regulators of cardiac function.Abbreviations Ca ²⁺ Calcium - Da dalton - IgG immunoglobulins - Na ⁺ Sodium - K ⁺ potassium     

Effect of phosphorus dendrimers on DMPC lipid membranes

Large unilamellar liposomes and multilamellar vesicles consisting of DMPC interacted with cationic phosphorus-containing dendrimers CPDs G3 and G4. DSC and ζ-potential measurements have shown that liposomal-dendrimeric molecular recognition probably occurs due to the interaction between the complementary surface groups. Calorimetric studies indicate that the enthalpy of the transition of the lipids that interact with CPDs is dependent on the dendrimers generation. These results can be used in order to rationally design mixed modulatory liposomal locked-in dendrimeric, drug delivery nano systems.     

Effect of cholesterol on multiplication,lipid metabolism and lysosomal enzymes ofHartmanella culbertsoni

Addition of sonicated dispersions of cholesterol to peptone-salt-vitamin medium resulted in the metabolism of the sterol byHartmanella culbertsoni. Trophozoite multiplication was stimulated at 1–5 mg/litre, but retarded at 10–20 mg/litre. When cholesterol was added to the medium, incorporation of [1,2-¹⁴C] -acetate into neutral lipid, phospholipid, non-saponifiable and cholesterol fractions of the amoebae was significantly reduced. Cholesterol ester was detected in the medium but phospholipids were not released. Addition of cholesterol stimulated the activity of lysosomal acid phosphatase, acid deoxyribonuclease and cathepsin B but did not affect 5′-nucleotidase, adenosine triphosphatase, alkaline phosphatase, glucose-6-phosphatase, succinate dehydrogenase and cytochrome C oxidase. Communication No.2486     

Caveolin, cholesterol, and lipid bodies

In mammalian cells a complex interplay regulates the distribution of cholesterol between intracellular membrane compartments. One important aspect of cholesterol regulation is intracellular cholesterol storage in neutral lipid storage organelles called lipid droplets or lipid bodies (LBs). Recent work has thrust the LB into the limelight as a complex and dynamic cellular organelle. LBs play a crucial role in maintaining the cellular levels of cholesterol by regulating the interplay between lipid storage, hydrolysis and trafficking. Studies of caveolins, caveolar membrane proteins linked to lipid regulation, are providing new insights into the role of LBs in regulating cholesterol balance.     

Effect of lipopolysaccharide toxin on lipid and protein composition of human serum low density lipoproteins

Complexes of lipopolysaccharide (LPS) B of Salmonella typhimurium with human low density lipoproteins (LDL) formed during in vitro coincubation via spontaneous incorporation of LPS (complex LDL-LPS) or through the incorporation stimulated by the serum protein fraction (LPS/LDL complex) were studied. The LPS/LDL complex was shown to maximally bind 0.24 mg of LPS per 1 mg of LDL protein, whereas the LDL-LPS complex contained only 0.07 mg of LPS per 1 mg of LDL protein. The observed incorporation of LPS into LDL particles was not possibly associated with a transfer of lipids or proteins from high density lipoproteins to LDL. The insertion of LPS was probably accompanied by the expulsion of a small portion of phosphatidylcholine molecules from the outer monolayer of LDL into the aqueous medium and by an increase in the phosphatidylethanolamine concentration in LDL. Simultaneously, the level of esterified cholesterol in the LPS/LDL complex decreased, and the concentrations of free cholesterol and triacylglycerols showed a rise. The level of free fatty acids in the LPS/LDL complex increased more than twofold compared with intact LDL. The enhancement of LPS incorporation did not result in the insertion of any serum proteins into LDL, in which apoB-100 remained the major apolipoprotein (ca. 90%); apoB-100 fragments made up to 5-7%, whereas apoE and apoC contained altogether ca. 3-5%. It is suggested that the LPS/LDL complex obtained can bind to three types of cell receptors, i.e., apoB/E receptors, LPS receptors and scavenger receptors of macrophages (monocytes); the increased level of free fatty acids in the LPS/LDL complex may accelerate its subsequent catabolism.