bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on the 12α and 26‐hydroxylation of bile alcohols by rabbit liver microsomes
Authors: Nicolau Gabriela , Cohen Bertram I. , Salen Gerald , Mosbach Erwin H. 
Published: November 2006

Abstract12α‐Hydroxylation of two C27‐steroids by rabbit liver microsomes was studied. Optimal assay conditions were determined with 7α‐hydroxy‐4‐cholesten‐3‐one and 5β‐cholestane‐3α,7α‐diol as substrates. The rate of 12α‐hydroxylation of 7α‐hydroxy‐4‐cholesten‐3‐one was found to be greater than that of 5β‐cholestane‐3α,7α‐diol by ca. 60%. Microsomal 26‐hydroxylation of 5β‐cholestane‐3α7α‐diol was also measured, and the ratio of 26‐hydroxylation to 12α‐hydroxylation of 5β‐cholestane‐3α,7α‐diol was found to be ca. 0.4. Rabbit liver 12‐αhydroxylase was more active than that of three other species (man, rat, monkey), explaining in part the predominance of cholic acid in rabbit bile.
Variations in lipid composition and sound velocity in melon from the North Atlantic pilot whale,Globicephala melaena melaena
Authors: Blomberg Jonas , Lindholm Lars‐Erik 
Published: November 2006

AbstractNonpolar lipids and sound velocity at different distances from the skin surface within a sample of pilot whale melon were studied. Thin layer chromatography, sensitive radioisotopic methods, and an ultrasonic echo scanner were used. Wax esters had a maximum concentration at 11–12 cm from the skin surface. Non‐ and monoisovalero triglycerides both exhibited a minimum at 8–10 cm, whereas the diisovalero species increased steadily from the skin surface towards the center of the pilot whale head. A minimum of sound velocity, ca. 1340 m/s, was found at 9–11 cm, thus coinciding with a region rich in isovaleric acid esterified in wax and diisovalero triglycerides. These findings are compatible with predictions based on the known correlations between lipid structure and sound velocity. Consequently, additional evidence for refraction of sound in pilot whale melon is presented. This is important in understanding the system of echolocation of toothed whales.
Effects of diet and type IIa hyperlipoproteinemia upon structure of triacylglycerols and phosphatidyl cholines from human plasma lipoproteins
Authors: Gordon Dennis T. , Pitas Robert E. , Jensen Robert G. 
Published: November 2006

AbstractFour normal and two individuals with Type IIa hyperlipoproteinemia were placed on the National Heart and Lung Institute Type IIa diet (low cholesterol, <300 mg/day, high polyunsaturated, low saturated fat diet) for 1 week and on a normal diet the following week. Plasma samples were obtained and the triacylglycerols, phospholipids, and cholesterol contents of plasma and of very low density lipoproteins, low density lipoproteins, and high density lipoproteins determined. Triacylglycerol fatty acid composition was determined and stereospecific analyses of triaclglycerols and phosphatidyl cholines performed. Structural determinations were limited to one normal and one Type IIa individual. In normal and Type IIa individuals, chylomicrons contained twice the amount of 18∶0 as did the very low density lipoproteins, low density lipoproteins, or high density lipoproteins. The structure of the triacylglycerols from the very low density lipoproteins and low density lipoproteins was asymmetric with at least 50M% 16∶0 in thesn‐1 position and mostly 18∶1 in positionssn‐2 and 3. There was a marked difference in the distribution of 18∶2 in low density lipoproteins of the normal and Type IIa individuals. The control contained equal amounts of 18∶2 in thesn‐1 andsn‐3 positions, whereas IIa low density lipoprotein was asymmetric with 26% of the 18∶2 in positionsn‐1 and 3% in thesn‐3 position. Very low density lipoprotein was asymmetric with regard to 18∶2 in control and IIa samples with an average of 5% of the 18∶2 in positionsn‐1 and 40% in positionsn‐3. The phosphatidyl cholines contained predominantly 16∶0 and 18∶0 in positionsn‐1, whereas the acids in positionsn‐2 were unsaturated with very little difference between lipoprotein classes. Neither the short dietary periods nor source of plasma affected the structure of the phosphatidyl cholines.
Reaction of anti‐phosphatidyl inositol antisera with neural membranes
Authors: Guarnieri Michael 
Published: November 2006

AbstractCa. 15% of the phosphatidyl inositol in myelin and microsomal membranes from rat brain was detectable by antiphosphatidyl inositol antibody. Antibody‐detectable phosphatidyl inositol in myelin and microsomes readily increased when the membranes were incubated at 45 C with the antiserum. Synaptic membranes also had only a limited capacity to adsorb antibody. Quantitative binding studies with synaptic membranes and mitochondria were limited, because these membranes contain cardiolipin, which cross reacts with phosphatidyl inositol antisera. Moreover, highly purified synaptic and mitochondrial membranes contain appreciable amounts of other membrane fractions.
Fluorescent pigments from uterus of vitamin E‐deficient rats
Authors: Desai I. D. , Fletcher B. L. , Tappel A. L. 
Published: November 2006

AbstractSpectrophotofluorometric analyses of the extracts of uterus from sterile rats maintained on a vitamin E‐deficient diet for a prolonged period of time indicated that the brown ceroid‐like pigments present were highly fluorescent, having characteristics typical of products formed during lipid peroxidation in vivo. The aqueous‐methanol layer of the uteral extract from vitamin E‐deficient animals had higher fluorescence than the corresponding chloroform layer, indicating the presence of more polar water‐soluble pigments than those found in most other tissues so far examined.
Use of internal vial for determining quench correction in scintillation counting of heterogeneous media
Authors: Noble R. C. 
Published: November 2006

AbstractAn insert vial situated at the center of the counting medium and containing a standard count has been used for quench correction in the liquid scintillation counting of gels containing suspensions of silicic acid scrapings from thin layer chromatoplates. The method has provided a simple and direct means of routine count correction for a range of14C‐labeled lipid classes following separation on thin layer chromatoplates. The use of insert vial provides several advantages over other methods for the count correction of these suspensions.
D‐galactosamine induced fatty liver: II. Analyses of hepatic lipid compositions
Authors: Morita A. 
Published: November 2006

AbstractFemale rats of the Wistar strain received six separate intraperitoneal injections of D‐galactosamine (250 mg/kg body wt per single injection). The rats were sacrificed 48 hr after the initial injection and the livers analyzed for their lipid compositions. A marked increase in the levels of total lipids and triglyceride with a pronounced decrease in phospholipid content in the liver was observed. However the percentage of individual phospholipid fractions obtained by thin layer chromatography showed no significant changes after D‐galactosamine administration, except for a slight increase in lysophosphatidylcholine. Fatty acid analyses of total lipids and phospholipids demonstrated an increase in the percentage of oleic and linoleic acids, with a decrease in the percentage of arachidonic acid after D‐galactosamine administration. In the triglyceride fraction, a slight increase in the percentage of myristic, palmitoleic and linolenic acids was observed.
Mass spectral analysis of eleven analogs of vitamin A
Authors: Reid R. , Nelson E. C. , Mitchell E. D. , McGregor M. L. , Waller G. R. , John K. V. 
Published: November 2006

AbstractThe low resolution mass spectra of 5,6‐monoepoxyretinoic acid, 5,8‐monoepoxyretinoic acid, 5,6‐monoepoxyretinyl acetate, 5,8‐monoepoxyretinyl acetate, 5,8‐monoepoxyretinal, trimethylsilyl‐5,6‐monoepoxyretinoate, trimethylsilyl‐5,8‐monoepoxyretinoate, methyl‐5,6‐monoepoxyretinoate, methyl‐5,8‐monoepoxyretinoate, β‐C19‐retinal and β‐C19‐retinyl acetate‐analogs of vitamin A—are presented. Characteristic features of the spectra are discussed. In addition, high resolution mass measurements are presented for six fragment ions of all‐trans‐retinoic acid and eleven fragment ions of methyl‐5,6‐monoepoxyretinoate.
Antagonistic effects ofMyxococcus xanthus on fungi: II. Isolation and characterization of inhibitory lipid factors
Authors: Norén Börje , Odham Göran 
Published: November 2006

AbstractThe chemical composition of the lipophilic excretion ofMyxococcus xanthus inhibitory to the germination of fungal spores and growth has been investigated. The inhibitory effect was attributed to a mixture of fungistatically acting fatty acids and a component of antibiotic character. The fatty acid mixture has been fully characterized and found to constitute a mixture of saturated (68%) and unsaturated (32%) structures in the C13–C17 range. The major part is methylbranched of theiso‐type, with 13‐methyltetradecanoic acid being the main component (33% of the total). The fungistatic activity of the fatty acid mixture on spore germination is attributed to the structures withiso‐configuration. The presence of unsaturation is of minor importance. Observed morphological changes of the spores and hyphae in the presence ofiso‐fatty acids suggest that they act on the plasma membrane.
Enzymatic conversion of 5α‐cholesta‐7,14‐dien‐3β‐ol to 5α‐cholesta‐8,14‐dien‐3β‐ol
Authors: Hsiung H. M. , Spike T. E. , Schroepfer G. J. 
Published: November 2006

Abstract5α‐Cholesta‐7,14‐dien‐3β‐ol, previously shown to be efficiently converted to cholesterol upon incubation with rat liver homogenate preparations under aerobic conditions, has been studied as to its possible conversion to 5α‐cholesta‐8,14‐dien‐3β‐ol. Efficient conversion was observed upon incubation in the presence of washed microsomes of rat liver under anaerobic conditions. This observation is of importance in consideration of possible metabolic pathways in the biosynthesis of cholesterol.
Studies on tocopherol derivatives: V. Intestinal absorption of several d,1‐3,4‐3H2‐α‐tocopheryl esters in the rat
Authors: Nakamura T. , Aoyama Y. , Fujita T. , Katsui G. 
Published: November 2006

AbstractTwelve d,1‐3,4‐3H2‐α‐tocopheryl esters were synthesized from d,1‐3,4‐3H2‐α‐tocopherol. They were acetate, propionate, butyrate, isobutyrate, caprylate, palmitate, acid succinate, benzoate, nicotinate, o‐hydroxybenzoate, o‐acetoxybenzoate, and pivalate. The hydrolysis of these esters with bile‐pancreatic juice and with 9,000 × g supernatant of small intestine and liver homogenates of rats was examined. When these esters were incubated in small intestine or liver supernatants, hydrolysis occurred at a similar rate. In the incubation experiments, α‐tocopheryl acetate, propionate, butyrate, isobutyrate, caprylate, palmitate, and acid succinate were classified as an easily hydrolyzable group. α‐Tocopheryl benzoate and nicotinate were in a moderately hydrolyzable group. o‐Hydroxybenzoate and pivalate, which resisted hydrolysis, were in a scarcely hydrolyzable group. o‐Acetoxybenzoate was easily hydrolyzed to the o‐hydroxybenzoate. Hydrolysis on straight chain fatty acid esters of α‐tocopherol easily occurred in bile‐pancreatic juice. In in vivo experiments, the lymphatic absorption rate of 6 esters, acetate, palmitate, acid succinate, nicotinate, o‐hydroxybenzoate, and pivalate, was measured on thoracic duct fistula rats. Easily hydrolyzable esters were recovered mostly in lymph as α‐tocopherol, whereas, an ester which strongly resisted hydrolysis, such as pivalate, appeared mainly unchanged. This fact suggested that hydrolysis of α‐tocopheryl esters was not necessarily a prerequisite for intestinal absorption. The percentage of absorption of slowly hydrolyzed esters in lymph was relatively lower than that of moderately or easily hydrolyzable esters.
Dietary alteration of fatty acid composition of lipid classes in mouse mammary adenocarcinoma
Authors: Rao G. Ananda , Abraham S. 
Published: November 2006

AbstractThe composition of total fatty acids in serially transplanted mammary adenocarcinomas of C3H mice which were fed a fat free diet or a stock diet containing 4% fat for 8 weeks were significantly different, although fatty acid amounts were similar. The difference in composition was manifested in the triglyceride, phosphatidyl choline, and phosphatidyl ethanolamine fractions. Tumors of mice fed fat free diet had appreciable amounts of eicosatrienoic acid, whereas neoplasms of stock diet fed animals had none. In addition, higher levels of oleic acid and lower contents of linoleic acid were found in tumors from mice fed fat free diet than in those from mice fed the stock diet. Thus, mechanisms which maintained the triglyceride fatty acid composition in some tumors, such as 7288CTC hepatoma, were not observed in mouse mammary adenocarcinomas, and, therefore, were not a general phenomena associated with carcinogenesis.
Effect of diet on the composition of cholesteryl esters of sheep adrenals
Authors: Christie W. W. , Hunter M. L. , Moore J. H. , Noble R. C. , Vernon R. G. 
Published: November 2006

AbstractFatty acid components of cholesteryl esters from the adrenals of sheep, like those of nonruminants, were characterized by significant amounts of the longer chain metabolites of linoleic acid. Administration to sheep of diets rich in linoleic acid and protected against biohydrogenation did not alter the concentration of these components significantly. Although 18∶2 levels were elevated, this was largely at the expense ofcis‐monoenoic fatty acids.
Inhibition of cholesterol absorption by (−)N‐[α‐phenyl‐β‐(p‐tolyl) ethyl] linoleamide in rats
Authors: Nagata Akihiko , Nakatani Hiroshi , Toki Katsuyuki 
Published: November 2006

AbstractThe effect of (−)N‐[α‐phenyl‐β‐(p‐tolyl)ethyl] linoleamide (PTLA) on intestinal absorption of cholesterol was studied in rats. Oral administration of 15 mg PTLA to rats resulted in a significant (P<0.05) decrease in the radioactivity in serum and liver 4 hr after administration of labeled cholesterol. The effect of PTLA was greater on the absorption of cholesteryl oleate as compared with free cholesterol. The rate of hydrolysis of cholesteryl oleate in mucosal homogenates of rat intestine was decreased with PTLA, suggesting that the inhibition of cholesterol absorption by PTLA is related to its effect on cholesteryl ester hydrolysis in the intestine.
Effects of colestipol hydrochloride and neomycin sulfate on cholesterol turnover in the rat
Authors: Phillips William A. , Elfring Gary L. 
Published: November 2006

AbstractThree groups of male rats were fed diets containing the bile acid sequestrant colestipol hydrochloride (1%), neomycin sulfate (0.25%), or basic diet during the test. After 15 days, each rat was injected IV with 3.9 μCi cholesterol‐1,2‐3H complexed with serum lipoproteins; specific radioactivity of the total serum cholesterol was measured at several time intervals for a period of 7 weeks. Computer analysis of the data indicated that the turnover of cholesterol could best be fitted by a three‐pool model. In pool 1, colestipol HCl caused a significant increase in production rate (10.09 to 15.96 mg/day) and the excretion rate constant (0.53 to 0.79 day−1) of cholesterol without significantly altering the size of the pool or serum cholesterol concentrations. These results are compatible with an agent capable of binding bile acids in the rat but do not cause a decrease of the sterol pool because of an adequate compensatory increase in cholesterol biosynthesis. Neomycin SO4 caused a significant reduction in serum cholesterol (9%) without altering turnover parameters and apparently exerts its hypocholesterolemia by some mechanism other than bile acid sequestration.
Studies on the mechanism of action of halofenate
Authors: Mandel Lewis R. 
Published: November 2006

AbstractThis paper reviews most of the preclinical studies on the mode of action of halofenate, an established hypolipidemic‐hypouricemic agent in man. In yeast cultures and in isolated rat adipocytes, halofenate was found to inhibit the conversion of pyruvate to acetyl CoA. While pyruvate dehydrogenase was inhibited in vitro, halofenate also inhibited the activity of various other isolated enzymes. In rats maintained on halofenate in the diet (0.02–0.10%) for 2–14 days, there were 20–40% decreases in plasma cholesterol, trigly cerides, phospholipids, and free fatty acids. Inhibition of liver HMG‐CoA reductase does not appear to account for the hypocholesterolemic effect, and activation of mitochondrial α‐glycerophosphate dehydrogenase does not explain the hypotriglyceridemic action. Kinetic measurements of the serum appearance and disappearance of triglycerides in drug‐treated rats suggest that the hypotriglyceridemic activity is due to a net inhibition of hepatic triglyceride synthesis. Reduction of very low density lipoprotein (VLDL) and high density lipoprotein (HDL) levels in rats with sucrose‐induced hyperlipidemia and normalization of the altered apolipoprotein profiles are in accord with the effects of halofenate on plasma triglyceride and cholesterol levels. The reduced insulin‐to‐glucagon ratio observed in Zucker obese hyperlipemic rats is also consistent with halofenate's hypotriglyceridemic activity. Preliminary experiments in rats on the mechanism of its hypoglycemic activity, observed in some diabetic hyperlipidemic patients, indicate that halofenate acts differently than conventional oral hypoglycemic agents. Some, but not all, of the effects of halofenate were observed with clofibrate at two to ten times higher levels.
FDA considerations regarding new hypolipidemic agents
Authors: Finkel Marion J. 
Published: November 2006

AbstractFood and Drug Administration policy being considered for new marketed hypolipidemic agents includes: long‐term safety to be demonstrated in postmarketing studies; evidence of clinical effectiveness to be demonstrated within a specified time period. Effectiveness is to be judged by one or more of the following: reduction in xanthomata, reduction in atherosclerotic plaque, reduction in morbidity of coronary artery disease or peripheral and cerebral atherosclerosis, and reduction in mortality. Randomized double blind trials are deemed necessary.
Regulation of fatty acid biosynthesis in Ehrlich cells by ascites tumor plasma lipoproteins
Authors: McGee Richard , Brenneman Douglas E. , Spector Arthur A. 
Published: November 2006

AbstractFatty acid biosynthesis in Ehrlich cells in vitro was reduced when very low density lipoproteins (VLDL) isolated from the ascites tumor plasma were added to the incubation medium. The degree of inhibition was dependent on the VLDL concentration. At the VLDL concentrations usually present in the ascites plasma, there was a 30% decrease in biosynthesis as measured by3H2O incorporation into fatty acids. Analysis of the labeled fatty acids by gas liquid chromatography indicated that this decrease was due to a reduction in fatty acid de novo biosynthesis and that chain elongation actually was increased when VLDL were present. Although ascites plasma low‐ and high density lipoproteins also produced a concentration‐dependent inhibition of fatty acid biosynthesis, their effects were much smaller than those of the VLDL. Studies employing VLDL and radioactive free fatty acids indicated that the cells took up and utilized fatty acids derived from these lipoproteins. When VLDL were present, labeled free fatty acid incorporation into cell phospholipids, cholesteryl esters, and CO2 decreased, whereas its incorporation into the cell free fatty acid pool increased. By contrast, the cells incorporated only very small amounts of fatty acid from either low‐ or high density lipoproteins. This suggests that the VLDL exert their inhibitory effect on fatty acid synthesis by supplying exogenous fatty acids to the cells.
Serum lipoproteins as inhibitors of haemagglutination by rubella virus
Authors: Ho W. K. K. , Shortridge K. F. 
Published: November 2006

AbstractThe role of serum lipoproteins as nonantibody‐like inhibitors of haemagglutination for rubella virus was investigated. Dissociation of lipoproteins into their respective lipid and protein components significantly reduced their inhibitory titre. This reduction was more prominent with the protein component. When mixtures of pure lipids were tested for their haemagglutination inhibitory activities, no inhibition was observed. Sonication of the three major lipoprotein fractions significantly increased the inhibitory activities of low density lipoproteins (LDL) and very low density lipoproteins (VLDL) but not high density lipoproteins (HDL). Succinylation, acetylation, and methylation of the lipoproteins did not appear to affect their inhibitory titre. On the other hand, phospholipase A treatment significantly increased the inhibitory properties of all lipoproteins fractions. These results are discussed in terms of the possible mechanisms by which the lipoproteins interact with the rubella haemagglutinins.
The phytanic acid content of the lipids of bovine tissues and milk
Authors: Lough A. K. 
Published: November 2006

AbstractIn three steers which were given grass silage for six months, the content of phytanic acid (i.e. 3,7,11,15‐tetramethylhexadecanoic acid) in plasma lipid increased to about 8% of the total fatty acids, whereas after this time the proportion in the total fatty acids of liver and heart lipids was about 1%, and only 0.1% in those of kidney lipids; the acid was present in trace amounts in adipose‐tissue triglycerides and was apparently absent from brain lipids. In eight lactating cows which were given grass silage for about 3 months, the content of phytanic acid in the total long chain fatty acids of milk and of plasma was 0.7% and 13%, respectively. In the plasma lipids of both steers and lactating cows, phytanic acid constituted a substantial proportion of the total fatty acids of the triglycerides and phospholipids; the acid was present in lowest proportion in the cholesteryl esters.
Metabolism of chenodeoxycholic acid in hamsters
Authors: Tateyama Tadashi , Katayama Kouichi 
Published: November 2006

AbstractThe study on the metabolism after oral administration of chenodeoxycholic acid‐24‐14C was performed by analysis of radioactivity that had appeared in bile and feces of male hamsters. The radioactive bile acids were analyzed by thin layer chromatography and identified by the isotope dilution method. In the bile of the hamsters with bile fistula, radioactivity was originated from unchanged chenodeoxycholic acid for the most part, and 7‐ketolithocholic acid, lithocholic acid, and β‐muricholic acid for the remainder. In the feces lithocholic acid, dehydrolithocholic acid, isolithocholic acid, and unchanged form were identified. After the multiple dosing of chenodeoxycholic acid‐24‐14C for 6 days, β‐muricholic acid was also identified in the feces.
The occurrence and distribution of octadecapentaenoic acid in a natural plankton population. A possible food chain index
Authors: Mayzaud P. , Eaton C. A. , Ackman R. G. 
Published: November 2006

AbstractIt is shown that marine dinoflagellates under natural conditions synthesize the unusual fatty acid octapentadecaenoic (18∶5ω3). This acid is very likely a characteristic of certain groups of phytoplankters and is not an artifact from artificial culture conditions. Various species of herbivorous copepods as well as contemporary carnivorous chaetognaths living in the same environment present traces of this fatty acid. The decreasing quantity of 18∶5ω3 on moving up the food chain, and its absence in certain species, makes it a possible ecological tracer.