bluuebunny/crossref_metadata_2025 huggingface dataset:
Distribution of antithrombin III and glucosylceramide in human plasma lipoproteins and lipoprotein deficient plasma
Authors: Chatterjee Subroto , Bell William R. , Kwiterovich Peter O.
Published: December 2006

We have investigated the distribution of antithrombin‐III and glucosylceramide (Glc‐Cer) in human plasma, plasma lipoproteins and lipoprotein‐deficient plasma. Antithrom bin III activity was measured employing immunochemical and biological assays. Glc‐Cer was quantified by gas liquid chromatography (GLC). Whole plasma contained 145 μg antithrombin III/ml plasma, all of which was associated with the lipoprotein‐deficient plasma (d>1.25 g/ml). Whereas, most if not all the plasma GlcCer was associated with plasma low density lipoproteins (LDL) (d‐1.022–1.055 g/ml) and high density lipoproteins (HDL) (d‐1.063–1.25). GlcCer was not found in the lipoprotein‐deficient plasma. We conclude that GlcCer on lipoproteins does not contribute to antithrombin III activity. Moreover, the absence of GlcCer in lipoprotein‐deficient plasma does not impair antithrombin‐III activity.
Microsomal phosphatidylethanolamine methyltransferase: Inhibition by S‐adenosylhomocysteine
Authors: Hoffman Dennis R. , Haning Judy A. , Cornatzer W. E.
Published: December 2006

Inhibition by S‐adenosylhomocysteine (AdoHcy) of the three reactions of phosphatidylethanolamine methyltransferase which catalyzes the production of phosphatidylcholine from phosphatidyl‐ethanolamine in guinea pig and rat liver microsomes has been evaluated. Five of the six methylation reactions in these two species exhibit greater affinity for inhibitor, AdoHcy, than for substrate, S‐adenosylmethionine (AdoMet). The Ki values for the rate‐limiting reactions were 3.8 μM and 68 μM in rat and guinea pig livers, respectively. An AdoMet:AdoHcy ratio of 12∶1 in developing liver was found to decline to a constant value in the adult of 5∶1. The concentration of AdoHcy in rat and guinea pig liver increases markedly following death of the animal. A concomitant decrease in the AdoMet level was observed in guinea pig liver. A comparison of phosphatidylethanolamine methyl‐transferase activity with the hepatic concentrations of AdoMet and AdoHcy in mouse, rat, rabbit and guinea pig is presented. Regulation of the methylation pathway is discussed.
Structure of biliary phosphatidylcholine in cholesterol gallstone patients
Authors: Cantafora A. , Angelico M. , Di Biase A. , Pièche U. , Bracci F. , Attili A. F. , Capocaccia L.
Published: December 2006

The fatty acid composition of biliary phosphatidylcholine was analyzed in 13 patients with radiolucent gallstones undergoing elective cholecystectomy, and in 11 normolipemic patients without gallstones undergoing abdominal surgery. The only difference in the percentage fatty acid composition between the two groups was a significantly (p<0.05) higher percentage arachidonic acid in the first group. This acid was exclusively located in thesn‐2 position of phosphatidylcholine (PC), accounting for 13.0±4.9% in the first group and 8.2±4.9% in the second (p<0.05). The percentage arachidonic acid of PC was negatively correlated (p<0.001) with the percentage biliary chenodeoxycholate in gallstone patients, but not in controls. Explanation of these findings is, at present, only speculative.
Utilization of polyunsaturated long‐chain alcohols byClostridium butyricum
Authors: Gilbertson J. R. , Crout R. J. , Gilbertson J. D.
Published: December 2006

When a trace amount of linolenyl alcohol (cis,cis,cis‐9,12,15‐octadecatriene‐1‐ol) was added to the culture media ofClostridium butyricum, the polyunsaturated alcohol was readily assimilated. After an initial 18‐hr exposure interval, there was a large increase in the amount and a change in the composition of thelong‐chain alcohols present. However, this alteration was temporary. As the duration of the exposure interval increased, the alcohol content and composition of the treated bacteria returned toward control values. This return of the long‐chain alcohol composition toward control values was associated with an increase in the proportion of linolenic acid in the phospholipid fraction. The ether moiety of the alk‐1‐enyl phosphoglycerides was unchanged in amount or composition upon exposure to linolenyl alcohol.
Alkane contamination of lipids extracted fromLagenidium giganteum andLagenidium callinectes
Authors: Warner S. A. , Graham M. S. , Sovocool G. W. , Domnas A. J.
Published: December 2006

Alkanes associated with the mycelia of the fungiLagenidium giganteum andL. callinectes were analyzed. Careful studies showed that these substances were contaminats derived from glass ware, media and solvents. No alkane biosynthesis or transformation was detected, indicating little or no alkane metabolism. The importance of using clean techniques, high‐purity solvents and proper media controls was emphasized.
Influence of vitamin E and nitrogen dioxide on lipid peroxidation in rat lung and liver microsomes
Authors: Sevanian Alex , Hacker Allen D. , Elsayed Nabil
Published: December 2006

Rat lung and liver microsomes were used to examine the effects of dietary vitamin E deficiency on membrane lipid peroxidation. Microsomes from vitamin‐E‐deficient rats displayed increased lipid peroxidation in comparison to microsomes from vitamin‐E‐supplemented controls. The extent of lipid peroxidation, as determined by measurement of thiobarbituric acid reacting materials, was enhanced by addition of reduced iron and ascorbate (or NADPH). Rats fed a vitamin‐E‐supplemented diet and exposed to 3 ppm NO2 for 7 days did not exhibit increases in microsomal lipid peroxidation compared to air‐breathing controls. However, increases were found in microsomes prepared from rats fed a vitamin‐E‐deficient diet and exposed to NO2. Lung microsomes from vitamin‐E‐fed rats contained almost 10 times as much vitamin E as liver microsomes when expressed in terms of polyunsaturated fatty acid content. The extent of lipid peroxidation was, in turn, considerably less in lung than in liver microsomes. Lipid peroxidation in lung microsomes from vitamin‐E‐deficient rats was comparable to liver microsomes from vitamin‐E‐supplemented rats as was the content of vitamin E in these respective microsomal samples. A combination of vitamin E deficiency and NO2 exposure resulted in the greatest increases in lung and liver microsomal lipid peroxidation with the largest relative increases occurring in lung microsomes. An inverse relationship was found between the extent of lipid peroxidation and vitamin E content. Most of the peroxidation in lung microsomes appeared to proceed nonenzymatically whereas peroxidation in liver was largely enzymatic. Vitamin E appears to be assimilated by the lung during oxidant inhalation, but with dietary vitamin E deprivation, the margin for protection in lung may be less than in liver.
Studies on the substrate specificity of purified human milk lipoprotein lipase
Authors: Wang C. ‐S. , Kuksis A. , Manganaro F.
Published: December 2006

The fatty acid specificity of purified human milk lipoprotein lipase was studied using the C18 to C54 (total acyl carbon number) saturated and the C54 mono‐, di‐ and triunsaturated monoacid triacylglycerols. Kinetic determinations indicated that the medium‐chain triacylglycerols were better substrates than long‐ or very short‐chain saturated triacylglycerols. The unsaturated triacylglycerols were hydrolyzed at rates comparable to that of tricaprylin with triolein having the highest rate of hydrolysis of the unsaturated species tested. The enzyme attacked the primary ester bond much more readily than the secondary ester bond. The purified human milk lipoprotein lipase showed a preferential stereospecific lipolysis of thesn‐1‐position of the triacylglycerol molecule.
Prostaglandin and acyl chain effects on glutamate dehydrogenase activity
Authors: Shafer Paul T. , Fiskin A. Max
Published: December 2006

Prostaglandins A1 (PGA1), A2, B1, B2, E1, E2, F1α, F2α, and 19 esterified natural fatty acids were tested as effectors of beef liver glutamate dehydrogenase (L‐glutamate: NAD(P)+, oxidoreductase [deaminating], EC 1.4.1.3). All prostaglandins tested are found to activate the enzyme initially, but only PGA2>PGB2≥PGA1 cause a subsequent time‐dependent loss (not inhibition) of NADH oxidation activity. Both PGA1 and PGA2 desensitize glutamate dehydrogenase to allosteric activation by ADP, whereas PGA2 and PGB2 desensitize to allosteric inactivation by GTP. Preincubation of enzyme with diethylstilbestrol prevents the initial activation by the PG. Of the methyl esters, only prostaglandin precursors inactivated the enzyme. Simultaneous desensitization to the ADP and GTP allosteric effects resulted. Multiple esterification to glycerol or phospholipids enhanced the action of linoleoyl and diminished the action of linolenoyl chains. Preincubation of the PGA with glutathione or cysteine prevents the inactivation; i.e., the sulfhydryl binding region of the prostaglandin must be free for enzyme to be inactivated. Sulfhydryl reagents also protect the enzyme from the effects of the unsaturated acyl chains, and pHMB mimics acyl protection against GTP allosteric inactivation. Where the lipid effector is active against sulfhydryl groups, the desensitizations to the ADP and GTP allosteric effectors are reciprocal. The initial activation, subsequent inactivation and desensitization to ADP and GTP are all characteristic of binding in the estrogen‐specific effector site, suggesting this site as the target for PG and acyl action. In the PGA2 activation, the effect is found to be amplified by the cooperativity of the enzyme at 1 PG molecule/6 molecules of GDH. We conclude from the action of the PG and structural analogs that the initial activation of glutamate dehydrogenase is caused by α,β‐unsaturated monoketo cyclopental structures. GTP inhibition is blocked primarily by diketo structures which eventually inactivate the enzyme. ADP activation is blocked by sulfhydryl binding of the unsaturated cyclopental keto structure of the PG. Appearance of a 270 nm absorbance simultaneous to the acyl effects on the enzyme suggests that conjugated unsaturations are responsible for the precursor's qualitatively similar action to that of the PG.
Analysis of autoxidized fats by gas chromatography‐mass spectrometry: VII. Volatile thermal decomposition products of pure hydroperoxides from autoxidized and photosensitized oxidized methyl oleate, linoleate and linolenate
Authors: Frankel Edwin N. , Neff William E. , Selke Edward
Published: December 2006

To clarify the sources of undesirable flavors, pure hydroperoxides from autoxidized and photosensitized oxidized fatty esters were thermally decomposed in the injector port of a gas chromatograph‐mass spectrometer system. Major volatile products were identified from the hydroperoxides of methyl oleate, linoleate and linolenate. Although the hydroperoxides from autoxidized esters are isomerically different in position and concentration than those from photosensitized oxidized esters, the same major volatile products were formed but in different relative amounts. Distinguishing volatiles were, however, produced from each type of hydroperoxide. The 9‐ and 10‐hydroperoxides of photosensitized oxidized methyl oleate were thermally isomerized in the injector port into a mixture of 8‐, 9‐, 10‐ and 11‐hydroperoxides similar to that of autoxidized methyl oleate. Under the same conditions, the hydroperoxides from autoxidized linoleate and linolenate did not undergo significant interconversion with those from the corresponding photosensitized oxidized esters. The compositions of the major volatile decomposition products are explained by the classical scheme involving carboncarbon scission on either side of alkoxy radical intermediates. Secondary reactions of hydroperoxides are also postulated, and the hydroperoxy cyclic peroxides from methyl linoleate (photosensitized oxidized) and methyl linolenate (both autoxidized and photosensitized oxidized) are suggested as important precursors of volatiles.
Effect of 2‐hexadecynoic acid on cultured 7288C hepatoma cells
Authors: Upreti Girish C. , Matocha Martha , Wood Randall
Published: December 2006

The effects of 2‐hexadecynoic acid on the growth and lipid metabolism of cultured 7288 (HTC) cells have been evaluated. Growth was inhibited by the acetylenic acid: the LD50 was 35–85 μM as determined by two methods at low and high cell densities. Reduced growth did not result from damaged plasma membranes as determined by α‐amino isobutyrate leakage. DNA synthesis was unaffected by the acetylenic acid and the effect on RNA and protein synthesis appeared to be secondary to the effects on lipid metabolism. The 2‐hexadecynoic acid inhibited lipid metabolism of the HTC cells at least at two levels. Data from both mass studies and radioactive acetate distributions in cellular and media lipids indicated that fatty acid elongation and acylation, especially triglyceride synthesis, were inhibited.
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

The 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

Chromatography 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

A 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

A 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

A 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

Weanling 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

Sodium 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

Phospholipid 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

This 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

This 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

A 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

Fatty 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

Various 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

Twenty‐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

The 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

Glass 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

The 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

Wild 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

Sonchus 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

A 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

A 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

Optimal 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.
Instability of malondialdehyde in the presence of H2O2: Implications for the thiobarbituric acid test
Authors: Kostka Peter , Kwan Chiu‐Yin
Published: December 2006

The content of thiobarbituric acid‐reactive material (primarily malondialdehyde) is frequently used to estimate the extent of lipid peroxide formation. How‐ever, malondialdehyde is unstable in the presence of millimolar concentrations of hydrogen peroxide. This observation considerably limits the applicability of the thiobarbituric acid test, as hydrogen peroxide is known to be formed in a number of lipid peroxidation‐promoting systems. The instability of malondialdehyde in the presence of hydrogen peroxide seems to account for the inconsistent outcomes in studies relating the manipulations of intermediate H2O2 levels to the initiation of lipid peroxidation.
Essential and nonessential fatty acid oxidation in mice bearing Ehrlich ascites carcinoma
Authors: Ookhtens Murad , Baker Nome
Published: December 2006

We tested the hypothesis that mobilized (essential) free fatty acids (FFA) are spared from oxidation in cancer‐bearing animals. We injected tracers [1‐14C]linoleate, [1‐14C] palmitate and NaH14CO3 intravenously as single rapid doses in separate groups of mice bearing Ehrlich ascites tumor (EAT) and controls, and measured breath14CO2. The data from NaH14CO3 injections were used to develop kinetic, compartmental models of the HCO3−‐CO2 systems. These models were integrated with our earlier model of plasma FFA turnover for control and EAT‐bearing mice. The integrated multicompartmental models were then fitted to breath14CO2 data from mice injected with tracer FFA to compute the rates of FFA oxidation. FFA were not spared from an oxidative fate in our cancer‐bearing vs normal animals; moreover, essential FFA were not preferentially spared from oxidation compared to nonessential FFA in the cancer‐bearing mice.
Hydroperoxides formed by ferrous ion‐catalyzed oxidation of methyl linolenate
Authors: Toyoda I. , Terao J. , Matsushita S.
Published: December 2006

An emulsion of methyl linolenate was allowed to oxidize with a catalyst of ferrous sulfate and ascorbic acid. Three oxidation products were isolated, and their hydrogenated derivatives were characterized as the isomeric mixture of methyl monohydroxyoctadecanoate (monoOH), methyl 9,16‐dihydroxyoctadecanoate (diOH), and the isomeric mixture of methyl trihydroxyoctadecanoate (triOH). The monoOH isomers and diOH apparently were derived from methyl monohydroperoxyoctadecatrienoate (monoHPO) and methyl dihydroperoxyoctadecatrienoate (diHPO), respectively. Two triOH isomers (the 9,10,12‐ and 13,15,16‐isomers) were thought to be derived from the products containing cyclic peroxide‐hydroperoxide structure. 9,16‐diHPO was produced by the incubation of monoHPO with ferrous sulfate and ascorbic acid. Moreover, the experiment using18O2 demonstrated that mono‐HPO yielded 9,16‐diHPO by reacting with oxygen molecule. 9,10,13‐ and/or 9,12,13‐ and 12,13,16‐ and/or 12,15,16‐triOH isomers were also detected in the hydrogenated derivatives of oxidation products from monoHPO.
Herbal remedies of the maritime Indians: Sterols and triterpenes ofTanacetum vulgare L. (Tansy)
Authors: Chandler R. F. , Hooper S. N. , Hooper D. L. , Jamieson W. D. , Lewis E.
Published: December 2006

Plant sterols and triterpenes exhibit a wide range of pharmacological activities. As part of our ongoing studies of the medicinal aspects of Maritime flora, particularly the herbal remedies of the Micmac and Malecite Indians, we determined the nature of the sterols and triterpenes ofTanacetum vulgare L. (Compositae)—a widely used herbal remedy usually referred to as tansy. By using thin layer and gas chromatographics, nuclear magnetic resonance (NMR) spectroscopy and combined gas chromatography‐mass spectrometry, we were able to identify β‐sitosterol as the major sterol and α‐amyrin as the major triterpene of tansy. We also identified the sterols stigmasterol, campesterol and cholesterol, and the triterpenes β‐amyrin and taraxasterol. A fourth triterpene was tentatively identified as pseudo‐taraxasterol. The successful therapeutic application of this herb may be due partly to the presence of one or more of these compounds. The sterols and triterpenes of tansy have not been previously reported; neither, to our knowledge, have the NMR spectra of the amyrins and the NMR and mass spectra of taraxasterol.
Tissue fatty acid changes and tumor incidence in C3H mice ingesting cottonseed oil
Authors: Tinsley Ian J. , Wilson Glenn , Lowry Robert R.
Published: December 2006

The incidence of spontaneous mammary tumors in C3H mice at 35 wk was higher in mice fed rations containing cottonseed oil than in mice fed fats of comparable fatty acid composition. The time to 50% (T50) incidence was also shorter in the first group. The fatty acid composition of tissue lipids from mice fed the cottonseed oil showed changes indicating the presence of cyclopropene fatty acids‐higher levels of saturates and lower oleate/stearate and palmitoleate/palmitate ratios. A possible association between the development of a spontaneous mammary tumor in the C3H mouse and the presence of cyclopropene fatty acids in the cottonseed oil is indicated.
Sedimentation equilibrium of human low density lipoprotein subfractions
Authors: Kahlon Talwinder S. , Adamson Gerald L. , Shen Mason M. S. , Lindgren Frank T.
Published: December 2006

The molecular weights of low density lipoprotein (LDL) subfractions were determined precisely by meniscus depletion sedimentation equilibrium. Equilibrium speeds ranged from 9743 to 5896 rpm. The average molecular weights of various LDL subfractions of Sfo values 9.49, 7.94, 6.42, 5.17, and 3.71 determined by sedimentation equilibrium were 2.97×106; 3.13×106; 2.89×106; 2.45 ×106; and 2.61×106 daltons, respectively; and their respective densities were 1.0267, 1.0306, 1.0358, 1.0422, and 1.0492 g/ml. Minimal hydrated molecular weights for these fractions determined by flotation velocity at 37,020 rpm were 2.57×106; 2.37×106; 2.09×106; 1.94×106; and 1.81 ×106 daltons; whereas similar molecular weights determined at 52,640 rpm were 2.53×106; 2.27 ×106; 1.99×106; 1.86×106; and 1.74×106 daltons for the respective LDL subfractions. Higher molecular weights of fractions 2 and 5 compared to their adjacent fractions 1 and 4 by sedimentation equilibrium are of great interest. The calculated frictional ratio f/fo from sedimentation equilibrium and flotation velocity data ranges from 1.10 to 1.31, suggesting complexity and asymmetry of LDL subfraction molecules. There is also evidence that compressibility of LDL molecules may be different than that for the salt solution under high g‐force. Assuming that redistributed LDL molecules at equilibrium under low g‐force are spherical, it is possible that the shape of LDL molecules undergoing flotation velocity determinations may be distorted in high g‐force conditions. Such distortion may be consistent with the high f/fo values obtained and may also be a basis for structural rearrangement and/or lipoprotein degradation with prolonged preparative ultracentrifugation at high g‐force and pressure.
Copper(II)‐catalyzed lipid peroxidation in liposomes and erythrocyte membranes
Authors: Chan Phillip C. , Peller Owen G. , Kesner Leo
Published: December 2006

Cu++ was uniquely capable of catalyzing the peroxidation of rat erythrocyte membrane lipid in the presence of 10 mM H2O2, whereas several other transition metal ions were without significant effect. In contrast, peroxidation of soybean phospholipid liposomes could be catalyzed with decreasing efficiency by Co++, Cu++, Pb++, or Cr+++ also in the presence of H2O2. The effect of imidazole on Cu++‐catalyzed lipid peroxidation was stimulatory in liposomes and inhibitory in membrane preparations, whereas EDTA, histidine, citrate and alanine inhibited peroxidation in both systems. EDTA could stop the peroxidation after initiation, but catalase could not, indicating that Cu++ alone was necessary for the propagation of the chain reaction. Competitive inhibition studies with various scavengers of hydroxyl radicals or singlet oxygen and the absence of significant reaction enhancement by D2O indicated that neither of these reactive oxygen species was a major mediator in the Cu++‐H2O2 oxidative system. A copper‐oxygen complex may be directly involved in the initiation of peroxidation. Normal erythrocyte membranes and phospholipid liposomes also differ in their sensitivities toward external oxidative stress. In the absence of H2O2, Cu++ (0.2 mM) was capable of catalyzing lipid peroxidation in liposomes, aged erythrocyte membranes and membranes from vitamin‐E‐deficient rats; however, freshly prepared membranes from control rats and liposomes containing α‐tocopherol required H2O2 greater than 2 mM for the catalytic effect of Cu++ to be observed.
Interaction of discoidal complexes of dimyristoyl phosphatidylcholine‐cholesterol‐apolipoprotein A‐I with human plasma high density lipoprotein HDL3
Authors: Jackson Richard L. , Cardin Alan D. , Barnhart Roger L. , Ashraf Muhammad , Johnson J. David
Published: December 2006

The interaction of human plasma high density lipoproteins (HDL3) with discoidal complexes of apolipoprotein A‐I (apoA‐I) and dimyristoyl phosphatidylcholine (DMPC) containing 0, 10, 20 or 30 mol % cholesterol was investigated. Discoidal complexes containing various amounts of cholesterol were prepared by incubating apoA‐I and DMPC‐cholesterol liposomes for 12 hr at 25 C; the protein‐lipid complexes were isolated by gel filtration chromatography on Bio‐Gel A15m. Increasing the cholesterol content from 0 to 30 mol % caused a decrease in the fluidity of the discoidal complexes as determined by fluorescence polarization with 1,6‐diphenyl‐1,3,5‐hexatriene; a reduced phase‐transition amplitude; a decrease in the ratio of apoA‐I to DMPC; and an increase in the width of the discoidal complexes as determined by electron microscopy after negative staining. Incubation of the apoA‐I‐lipid complexes with HDL3 resulted in a complete breakdown of the discoidal structures and a transfer of DMPC and cholesterol to HDL3. As a result of lipid transfer, there was an increase in the size of HDL3. These in vitro results may be of significance as they relate to the interconversion of HDL subfractions during lipoprotein‐lipase‐induced lipolysis of triglyceride‐rich lipoproteins.
Tissue culture of cocoa beans (Theobroma cacao L.): Incorporation of acetate and laurate into lipids of cultured cells
Authors: Tsai C. H. , Kinsella J. E.
Published: December 2006

Suspension cultures of cocoa bean tissue readily incorporated exogenous acetate into lipids. The distribution of radioactivity from acetate in individual lipid classes after 48 hr was 20, 5, 1, 15, 25, and 35% in triglycerides, diglycerides, free fatty acids, sterol esters, sterols and polar lipids, respectively. The labeled acetate was rapidly incorporated into various fatty acids within 2 hr. The [1‐14C] saturated fatty acids declined slightly after 4 hr, whereas [1‐14C] oleate declined significantly after 2 hr. There was a concomitant increase in [1‐14C] linoleate. The radioactivity associated with linolenate was relatively high up to 4 hr, declined by 24 hr, and then increased again. The kinetics of fatty acid labeling suggested that biosynthesis of linolenic acid in cocoa bean suspension culture may occur via the desaturation of linoleic acid and the chain elongation of dodecatrienoic acid. The patterns of fatty acid radiolabeling following incubation of cells with [1‐14C] laurate was consistent with this mechanism.