bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thyroid control over biomembranes: VI. Lipids in liver mitochondria and microsomes of hypothyroid rats
Authors: Hoch F. L. , Subramanian C. , Dhopeshwarkar G. A. , Mead J. F. 
Published: December 2006

AbstractThe lipids of liver mitochondria prepared from normal rats and from rats made hypothyroid by thyroidectomy and injection with131INa contained similar amounts, per mg protein, of total lipids, phospholipids, neutral lipids and lipid phosphorus. Hypothyroidism caused a doubling of the relative amounts of mitochondrial cardiolipins (CL; to 20.5% of the phospholipid P) and an accompanying trend (although statistically not significant) toward decreased amounts of both phosphatidylcholines (PC) and phosphatidylserines (PS), with phosphatidylethanolamines (PE) remaining unchanged. The pattern of elevated 18∶2 fatty acyl content and depleted 20∶4 acyl groups of the mitochondrial phospholipids of hypothyroid preparations was reflected to varying degrees in the resolved phospholipids, with PC showing greater degrees of abnormality than PE, and CL showing none. Hypothyroidism produced the same abnormal pattern of fatty acyl distributions in liver microsomal total lipids as was found in the mitochondria. Hypothyroid rats, when killed 6 hr after injection of [1‐14C] labeled linoleate, showed the following abnormalities: the liver incorporated less label into lipids, and converted 18∶2 not exclusively to 20∶4 (as normals do) but instead incorporated the label mainly into saturated fatty acids. These data, together with the known decrease in β‐oxidation, suggest that hypothyroidism involves possible defective step(s) in the conversion of 18∶2 to 20∶4.
Separation of wax esters from steryl esters by chromatography on magnesium hydroxide
Authors: Stewart Mary Ellen , Downing Donald T. 
Published: December 2006

AbstractChromatography of stearyl oleate and cholesteryl oleate on thin layer plates coated with magnesium hydroxide‐celite, 1:1, or magnesia‐celite, 1:1, showed that magnesium hydroxide had better resolving power for the separation of these wax ester and steryl ester model compounds than did magnesia, an adsorbent which has been used previously for this separation. By means of high pressure liquid chromatography on magnesium hydroxide, wax esters and steryl esters from the skin surface lipids of human, rat and monkey were separated completely and without hydrolysis.
Dry column method for the quantitative extraction and simultaneous class separation of lipids from muscle tissue
Authors: Marmer William N. , Maxwell Robert J. 
Published: December 2006

AbstractA method for lipid isolation is presented that is alternative to the traditional chloroform/methanol extraction methods. This new method allows lipid isolation by solvent elution of a dry column composed of a tissue sample, anhydrous sodium sulfate, and Celite 545 diatomaceous earth groud together. To isolate total lipids, the dry column is eluted with a mixture of dichloromethane/methanol (90∶10, v/v). Alternatively, the lipids may be isolated and simultaneously separated into neutral and polar fractions by a sequential elution procedure; neutral lipids free of polar lipids are eluted first with dichloromethane, followed by elution of polar lipids with the dichloromethane/methanol (90∶10) mixture. The two dry column methods‐isocratic or sequential elution‐were compared with the traditional chloroform/methanol methods by gravimetric, thin layer chromatographic and phosphorus analyses.
Formation of γ‐ketols from 13‐ and 9‐hydroperoxides of linolenic acid by flaxseed hydroperoxide isomerase
Authors: Feng Paul , Vick Brady A. , Zimmerman Don C. 
Published: December 2006

AbstractA reexamination of the flaxseed hydroperoxide isomerase reaction showed that a minor enzymic product (ca. 5%), identified as a γ‐ketol, was present. The substrates were the 13‐ or 9‐hydroperoxides of linolenic acid, which were converted to 9‐hydroxy‐12‐oxo‐cis‐15‐trans‐11‐octadecadienoic acid, respectively. These compounds were formed in addition to the major products reported earlier: a 12,13‐α‐ketol and 12‐oxo‐cis‐10,15‐phytodienoic acid from the 13‐isomer, and a 9,10‐α‐ketol from the 9‐isomer.
Lipoprotein lipase in cholesterol‐fed and control guinea pigs
Authors: Sasinowski Frank , Ostwald Rosemarie 
Published: December 2006

AbstractA study of the in vitro activity of lipoprotein lipase of guinea pigs has shown that (a) the lipolytic activity of activated post‐heparin serum is depressed in hypercholesteremic guinea pigs compared to the serum of normocholesteremic guinea pigs; and (b) this depressed lipolytic activity in hypercholesteremic guinea pigs is not due to the presence of an inhibitor.
Fatty liver of growing rats fed excess lysine and its prevention by adenine or allopurinol
Authors: Ulman E. A. , Ifft K. H. , Kari F. W. , Visek W. J. 
Published: December 2006

AbstractWeanling male Sprague‐Dawley rats were fed ad libitum 15% casein diets with and without 5.0% lysine‐HCl, 0.25% adenine sulfate or 0.1% allopurinol for 2 weeks. Addition of lysine alone depressed 2‐week growth from 94 to 65 g, increased average daily urinary orotic acid excretion from 0.39 to 1.77 mg and increased the percentage of total liver lipids from 3.6 to 11.2. Adenine or allopurinol did not change growth but markedly enhanced lysine‐induced orotic aciduria and completely prevented lysine‐induced fatty livers. Reports by others show that adenine and allopurinol also prevent fatty livers of rats fed arginine‐free diets or excess orotic acid. The authors conclude that lysine‐induced orotic aciduria results from arginine deficiency caused by antagonism of arginine function by lysine, and that lysine‐induced fatty liver probably results from a lesion identifical to that produced by feeding excess orotic acid.
Regulation of 3‐hydroxy‐3‐methylglutaryl CoA reductase by analogs of cholesterol and bile acids in cultured intestinal mucosa
Authors: Stange E. F. , Schneider A. , Preclik G. , Alavi M. , Ditschuneit H. 
Published: December 2006

AbstractSodium fusidate and its glycine conjugate, which have the same detergent properties as bile acids, significantly (p<0.05) stimulate HMG‐CoA reductase of cultured intestine below the critical micellar concentration (CMC) without affecting brush border enzymes. Above CMC, both amphiphiles are cytotoxic. At concentrations between 1 and 5 mM, sodium fusidate decreased cholesterol contents of cultured mucosa (p<0.05), the increase in synthesis only partially compensating for the sterol loss. Oxygenated sterols, 7‐keto‐ and 25‐hydroxycholesterol, also depleted mucosal cholesterol at 0.5 mM, exerting their effect differently by inhibiting HMG‐CoA reductase (p<0.01). In contrast to their marked effect on total mucosal cholesterol contents, brush border cholesterol was unaffected by both cholesterol and bile acid analogs.
Comparison of phospholipid profiles of primary adenocarcinoma in the lung and other organs
Authors: Itoh Kiyoharu , Nakamura Mitsushige , Akino Toyoaki 
Published: December 2006

AbstractPhospholipid profiles, particularly molecular structure of phosphatidylcholine, of human primary lung adenocarcinoma were compared with those of the histologically same type of carcinoma from other organs in order to search for a possibility that differentiates between primary and metastatic tumors in the lung. The saturated class, mainly containing palmitic acid at both positions, accounted for 20.8% of phosphatidylcholine in lung adenocarcinoma, whereas it accounted for only 6–10.7% in the adenocarcinoma of other organs. Adenocarcinoma of organs other than the lung had specific characteristics of unsaturated molecular classes of phosphatidylcholine for each organ. Stomach tumor had high contents of dienes and tetraenes with particularly high proportion of arachidonic acid at the 2‐position. Breast tumor had a high content of monoenes, containing palmitoleic acid at the 2‐position. Adenocarcinomas of rectum, colon and thyroid contained more dienes compared to lung adenocarcinoma.
Intestinal cholesterol uptake from phospholipid vesicles and from simple and mixed micelles
Authors: Thomson A. B. R. , Cleland L. 
Published: December 2006

AbstractThis study was undertaken in vitro to examine the rat jejunal uptake of cholesterol from phospholipid vesicles and from mixed bile salt micelles, under conditions of low effective resistance of the intestinal unstirred water layer. Cholesterol uptake Jd, occurred from vesicles only when the cholesterol: phospholipid ratio was high. The addition of phospholipid (PL) to micelles comprising 20 mM taurodeoxycholic acid (TDC) extended the concentration of cholesterol, beyond which the relationship between cholesterol concentration and uptake remained linear. When the concentration of cholesterol in the bulk phase was held constant and the concentration of TDC or of PL added to the TDC was increased, there was a decline in cholesterol uptake; this effect was masked when the concentration of TDC was high, or when higher concentrations of PL were added to the mixed micelle. When increasing concentrations of palmitic acid were added to mixed micelles composed of cholesterol, TDC and PL, the uptake of cholesterol decreased; in contrast, cholesterol uptake progressively increased when palmitic acid was added to simple TDC micelles. The results suggest that the mechanism responsible for cholesterol uptake may vary, depending on the nature of the constituents of the micelle, and it is proposed that PL inhibits the intestinal uptake of cholesterol by altering the partitioning of cholesterol out of the micelle.
Components of royal jelly: I. Identification of the organic acids
Authors: Lercker G. , Capella P. , Conte L. S. , Ruini F. , Giordani G. 
Published: December 2006

AbstractThis present work characterizes the fatty acid constituents of the lipid fraction of royal jelly. Among the organic acids found after fractionation by thin layer chromatography of the corresponding methyl esters, the following compounds were identified by combined GC‐MS: saturated and unsaturated linear fatty acids, saturated and unsaturated linear and branched dicarboxylic acids, mono‐and dihydroxy acids. The most common characteristic of the organic acids was that most contained 8 or 10 carbon atoms, whether saturated or unsaturated, linear or branched.
Rapid fractionation of human high density apolipoproteins by high performance liquid chromatography
Authors: Polacek Denise , Edelstein Celina , Scanu Angelo M. 
Published: December 2006

AbstractA simple and rapid fractionation procedure (30 min) has been developed for the isolation of the major apoproteins from human serum high density lipoproteins by molecular sieving in a high performance liquid chromatographic column. Apo A‐I, apoA‐II and the C peptides are quantitatively resolved up to a protein load of 3 mg. The technique has also been successfully applied to the final purification of A apoproteins which has been isolated by conventional chromatographic procedures and as a sensitive analytical tool for assessing apoprotein purity.
Distribution of long chain polyenoic acids among phospholipids of mouse testis
Authors: McLean Grogan W. 
Published: December 2006

AbstractFatty acid composition of phospholipid (PL) classes was measured in mouse testis. Among the long‐chain polyenoic acids (LCPA), 22∶6 was found in highest concentration in phosphatidylethanolamine (PE), whereas percentages of 20∶4 and 22∶5 were not different in PE than in phosphatidylcholine. Each PL class had a unique fatty acid composition which was also different from that of triglycerides and cholesteryl esters. Differential metabolisms of 22∶5 and 22∶6 suggest different roles for these fatty acids in mouse testis. Tissue‐specific functions of LCPA in mouse spermatogenesis may be divided between 22∶5 and 22∶6.
Covalent binding of peroxidized phospholipid to protein: III. Reaction of individual phospholipids with different proteins
Authors: Nielsen Henning 
Published: December 2006

AbstractVarious peroxidized phospholipids were reacted with proteins under N2. In all cases, phospholipid is bound covalently to the proteins whose molecular size is increased. Both the amount of bound phospholipid and the increase in molecular size of the protein depends on the nature of the phospholipid. Ultraviolet (UV) absorption of the proteins is increased in qualitatively similar ways. Their difference spectra, which show a gradual increase in absorption from 400 nm toward shorter wavelength, differ from that of malonaldehyde‐protein complexes. The various complexes of proteins and peroxidized phospholipids have similar fluorescence spectra showing two excitation maxima at 310–320 nm and at 340–350 nm, respectively, and emission maximum at ca. 400 nm. This is different from both fluorescence spectra of malonaldehyde‐protein complexes and fluorescence spectra reported for proteins after reaction with peroxidized polyunsaturated fatty acids. Amino groups of the proteins are consumed in the reaction with peroxidized phospholipids. Blocking the amino groups decreases the binding of phospholipid considerably. Besides amino groups, other structures of the protein molecule react with the peroxidized phospholipids. The similar features of UV absorption, fluorescence, decrease of amino groups, and covalently bound phospholipid phosphorus of the various complexes suggest that they are formed by common type of reactions. The reactions seem to be different from those generally believed important between peroxidized lipid and protein. Important reacting species are compounds other than malonaldehyde.
α‐Tocopherol and serum lipoproteins
Authors: Sundaram G. S. , London R. , Manimekalai S. , Nair P. P. , Goldstein P. 
Published: December 2006

AbstractTwenty‐six patients with clinically confirmed mammary dysplasia and five age‐matched controls were treated with α‐tocopherol, 600 mg/day. Serum samples collected on the 21st day of the menstrual cycle were analyzed for cholesterol in lipoprotein fractions, isolated by a combination of precipitation and ultracentrifugation techniques. Eighty‐five percent of patients showed objective and subjective remission from disease following therapy. In mammary dysplasia patients, the ratio of serum cholesterol/high density lipoprotein cholesterol was higher than those in age‐matched controls, an abnormality which was corrected by α‐tocopherol therapy. Furthermore, as a result of therapy, high density lipoproteins increased and ester cholesterol associated with low density lipoproteins decreased. The results suggest that α‐tocopherol may serve as an effective agent in treating patients with benign breast disease, as well as correct the inherent abnormality in serum cholesterol distribution in mammary dysplasia patients.
Effects of feeding chenodeoxycholic acid on metabolism of cholesterol and bile acids in germ‐free rats
Authors: Gustafsson Bengt E. , Angelin Bo , Björkhem Ingemar , Einarsson Kurt , Gustafsson Jan‐Åke 
Published: December 2006

AbstractThe aim of this investigation was to study the influence of chenodeoxycholic acid administration on cholesterol and bile acid synthesis in germ‐free rats. Seven rats were fed a basal diet and 2 groups of 4 rats received the same diet supplemented with 0.4 and 1% chenodeoxycholic acid, respectively. After 6 weeks, feces were collected in one 3‐ and one 4‐day pool for analysis of cholesterol and bile acids. When the sampling period was finished, the rats were killed and the liver microsomal fractions isolated. The activities of HMG CoA reductase and cholesterol 7α‐hydroxylase were determined, the 7α‐hydroxylase by a mass fragmentographic method. The 2 dominating bile acids in the untreated rats were cholic acid and β‐muricholic acid. During treatment with chenodeoxycholic acid, 60–70% of this bile acid was converted into α‐ and β‐muricholic acid, indicating a high activity of the 6β‐hydroxylase. The excretion of cholic acid was almost completely inhibited and the 7α‐hydroxylase activity was decreased ca 75% in the rats fed 1% chenodeoxycholic acid. The activity of the hepatic HMG CoA reductase was unchanged. The fecal excretion of cholesterol increased 2–3 times. An accumulation of cholesterol was seen in the rats treated with 1% chenodeoxycholic acid, which was probably a result of the decreased catabolism of cholesterol to bile acids.
The use of SP2340 glass capillary columns for the estimation of thetrans fatty acid content of foods
Authors: Lanza Elaine , Slover Hal T. 
Published: December 2006

AbstractGlass capillary gas chromatography (GCGC) on 100‐m and 60‐m SP2340 columns was used for quantitation of thetrans unsaturated fatty acids in shortenings and fast foods. The separation of thecis andtrans octadecenoates on GCGC was evaluated by preparatory argentation thin layer chromatography. In addition, thetrans content of shortening samples obtained by GCGC was compared totrans content determined by infrared analysis.
Chromatographic separation of the stereoisomers of α‐tocopherol
Authors: Slover H. T. , Thompson R. H. 
Published: December 2006

AbstractThe diastereoisomers of2‐ambo‐α‐tocopherol were completely separated as TMS ethers by gas chromatography on a 115 m × 0.25 mm glass capillary column coated with SP2340, at a column temperature of 195 C. In the same way,all‐rac‐α‐tocopherol was separated into four peaks, corresponding to the four racemates present, and having the same retention ratios as the four diastereoisomers of 4′‐ambo‐8′‐ambo‐α‐tocopherol (produced by the hydrogenation of natural α‐tocotrienol). Retention data and relative peak areas for the diastereoisomers of the synthesized α‐tocopherols and several commercial products were determined. Limited data on the isomers of other tocopherols also are reported.
The relationship between dietary phytosterols and the sterols of wild and cultivated oysters
Authors: Berenberg Cathy J. , Patterson Glenn W. 
Published: December 2006

AbstractWild oysters (Crassostrea virginica) contained cholesterol, 24‐methyl‐cholesta‐5, 22‐dienol, 24‐methylenecholesterol, 22‐dehydrocholesterol, 24‐methylcholesterol, 24‐ethylcholesterol, 24‐norcholesta‐5, 22‐dienol, 24‐ethylcholesta‐5, 22‐dienol and fucosterol. The same species was cultivated on a defined diet ofThalassiosira pseudonana andIsochrysis sp. The dietary algae were cultured and their sterol compositions were analyzed by gas chromatography and mass spectroscopy.T. pseudonana andIsochrysis sp. had 24‐methylenecholesterol and 24‐methyl‐cholesta‐5, 22‐dienol as their major sterols. The sterol composition of the cultivated oysters revealed the predominance of cholesterol (19%), 24‐methyl‐cholesta‐5, 22‐dienol (21%) and 24‐methylenecholesterol (46%). Therefore, oysters must be able to bioconvert phytosterols to cholesterol, concentrate dietary cholesterol, or synthesize cholesterol de novo.
Simultaneous determination ofSonchus arvensis L. triterpenes by gas chromatography‐mass spectrometry
Authors: Hooper S. N. , Chandler R. F. , Lewis E. , Jamieson W. D. 
Published: December 2006

AbstractSonchus arvensis L. or sow thistle has proved an excellent source of pentacylic triterpenes; triterpenes account for about 6% of the crude lipid extract or 0.2% of the dried plant. Composition of the triterpenoid fraction, as indicated by gas chromatography of the corresponding acetates, was α‐amyrin (9%), β‐amyrin (21%), lupeol (13%), taraxasterol (24%) and pseudo‐taraxasterol (12%). A single, long‐chain alcohol (16%) was also present. The nature of the triterpenoids was defined using gas chromatography and gas chromatography‐mass spectrometry (GC/MS) and confirmed by direct comparison with authentic samples. The use of combined GC/MS proved extremely valuable in the simultaneous analysis of a mixture of triterpene acetates and greatly reduced the time needed to phytochemically evaluate these compounds.
Application of a GC‐MS method using deuterated fatty acids for tracingcis‐vaccenic acid biosynthesis in kaki pulp
Authors: Shibahara Akira , Yamamoto Kohei , Takeoka Mariko , Kinoshita Akemi , Kajimoto Goro , Nakayama Takao , Noda Manjiro 
Published: December 2006

AbstractA gas chromatographic‐mass spectrometric method using [2,2‐2H2]fatty acids has been developed to trace the biosynthesis ofcis‐vaccenic (cis‐11‐octadecenoic) acid in higher plants. The deuterated fatty acids and other unlabeled fatty acids in the biosynthetic reaction mixture were converted into bis(methylthio) derivatives and analyzed by mass chromatography. The principle of this method was based on the shift of key fragment ions (containing two deuterium atoms) due to the cleavage between the methylthio‐substituted carbons. The labeled compounds were detected by the m/z values which shifted 2 mass units from those of the corresponding unlabeled compounds and estimated by a calibration curve based on the peak areas of the key fragment ions. For metabolic experiments, a homogenate fraction was prepared from the pulp part of maturing kaki (Diospyros kaki) fruit and incubated with ammonium [2,2‐2H2]palmitoleate (cis‐9‐hexadecenoate) or [2,2‐2H2]palmitoleoyl‐CoA. The incubation resulted in the formation of detectable amounts of isotopically‐labeledcis‐vaccenic acid containing two deuterium atoms at the carbon chain between the double bond and the carboxyl group. This experimental evidence proved thatcis‐vaccenic acid was formed from palmitoleic acid by chain elongation.
A novel spectrophotometric assay for lipase activity utilizingcis‐parinaric acid
Authors: Rogel A. M. , Stone W. L. , Adebonojo F. O. 
Published: December 2006

AbstractA new spectrophotometric assay for determining the activity of acylglycerol hydrolases (lipases, E.C. 3.1.1.3) was developed and optimized for yeast lipase (Candida cylindracea). Studies with porcine pancreatic lipase were also conducted and the influence of various detergents and divalent cations on the assay was evaluated. The assay usescis‐parinaric acid (PnA), a naturally occurring fatty acid that has unique spectroscopic properties, and takes advantage of the reversible binding of fatty acids to bovine serum albumin (BSA). Free PnA has an ultraviolet absorption peak at 321.2 nm. When PnA is bound to BSA, however, the peak shifts to 324.2 nm. The assay mixture contains 6 μM PnA, 1 μM BSA, 75 μM triolein, and 0.3 mM taurocholate in a 50 mM tris‐HCl buffer with 1 μM EDTA. The release of oleic acid from triolein is monitored over time by measuring the ratio of optical densities (OD) at 319.0 and 329.0 nm. Initially, there is maximum binding of PnA to BSA, and the OD ratio is approximately 1.0. Upon addition of lipase, PnA is displaced from the BSA by oleic acid released from triolein, and the OD ratio increases to a maximum of about 1.8. However, when calcium is present in the reaction mixture an insoluble calcium‐PnA complex forms, resulting in a progressive decrease in OD at both 319.0 and 329.0 nm. The kinetic assay described here is simple, rapid, sensitive, reproducible, inexpensive, and it can be adapted to measure the activity of a variety of calcium‐independent lipases. Under similar assay conditions, activities forCandida cylindracea lipase obtained with this assay are similar to those obtained with14C‐labelled triolein.
Determination of HDL2 cholesterol by precipitation with dextran sulfate and magnesium chloride: Establishing optimal conditions for rat plasma
Authors: Sjoblom Linnea , Eklund Anders 
Published: December 2006

AbstractOptimal conditions for analyzing HDL2 cholesterol in small amounts of rat plasma have been studied using different concentrations of dextran sulfate and MgCl2 to precipitate lipoproteins containing apolipoprotein B and/or apo E. When the MgCl2 level was 91 mM, the supernate cholesterol was rather constant at a level of about 50–60% of the total plasma cholesterol concentration. Immunochemical determination of the apo A‐I content indicated that no major losses of the HDL2 fraction took place under these conditions. The recovery of about 96% of HDL2 lipoproteins after the precipitation of rat plasma and the almost complete absence of lipoproteins belonging to the VLDL, LDL and HDL1 fractions was demonstrated by agarose gel electrophoresis. Thus, the method should be suitable for screening the HDL2 cholesterol content in small volumes of rat plasma.