bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dietary factors in arteriosclerosis: Sucrose
Authors: Yudkin John 
Published: November 2006

AbstractEpidemiological studies show that coronary heart disease is more common in wealthier countries than in poorer. Such studies cannot, however, isolate which of the dietary or nondietary characteristics of affluence help to cause the disease; they provide only clues that need to be subjected to experimental study. Experiments should be designed on the basis of their ability to produce the multiple abnormalties associated with coronary heat disease (CHD) and not only hypercholesterolemia. They should also explain the association of CHD with obesity, diabetes mellitus, cigarette smoking, and physical inactivity. These considerations suggest that the underlying abnormality that produces CHD is a disturbed hormonal balance. Experiments have shown that a high consumption of sucrose produces not only the wide range of abnormalities seen in CHD but also an increased blood concentration of insulin and cortisol. Since a low intake of sucrose confers many other health benefits, it is a more logical dietary recommendation than that of substituting polyunsaturated fat for saturated fat.
Arylsulfonate esters of fatty alcohols: IV. Effects on cholesterol catabolism
Authors: Klauda Harry C. , Bell Frank P. , Grogan W. McLean , Quackenbush Forrest W. 
Published: November 2006

AbstractHypercholesterolemic rats, fed 1% cholesterol and 0.5% glycocholate, were treated with arylsulfonates in various ways to observe the pattern of cholesterol elimination. Dietary linoleyl p‐toluene‐sulfonate (LTS) hastened return to normocholesterolemia and lowered hepatic cholesterol either with or without continued cholesterol feeding. LTS administered via the portal vein significantly lowered plasma cholesterol in 48 hr; ethyl linoleate and monoolein produced no lowering. LTS administered via the portal vein to glycocholate‐infused rats increased the biliary excretions of label from [4‐14C]cholesterol administered intracardially and also increased total bile acid excretion 21% without increased bile volume when compared to similar injection of ethyl linoleate. No change in biliary excretion of cholesterol was seen. Bile acid kinetics were studied by using isotopic dilution techniques. Cholate turnover was enhanced by feeding oleyl p‐toluenesulfonate (OTS) and oleylp‐(n‐decyl)‐benzenesulfonate (ODS) as suggested by a 16–35% decrease in half‐life in both normal and hypercholesterolemic rats. Rats consuming a grain‐based colony diet had a 54% increase in cholate synthesis when OTS was included in the diet. The composition of bile was changed when either OTS or ODS was fed; an increase in chenodeoxycholate was noted. This change was gradual with OTS but rapid with ODS and paralleled enhanced decay of chenodeoxycholate specific radioactivity in response to treatment. ODS and OTS also increased14CO2 expiration from oral [26‐14C] cholesterol in hypercholesterolemic rats. Dietary OTS and ODS elevated hepatic free cholesterol in hypercholesterolemic rats; ODS also elevated plasma free cholesterol and increased cholesteryl ester hydrolase activity in the liver. The data suggest that arylsulfonates stimulate cholesterol catabolism, in addition to the reported inhibition of cholesterol absorption [Lipids 12:819 (1977)].
Indomethacin stimulation of lipid peroxidation and chemiluminescense in rat liver microsomes
Authors: Pennington S. N. , Smith C. P. 
Published: November 2006

AbstractPeroxidation of endogenous lipid by rat liver microsomes, coupled with oxidation of reduced nicotinamide adenine dinucleotide phosphate (NADPH) and measured as thiobarbituric acid reactive materials, is markedly stimulated in the presence of indomethacin [1‐(p‐chlorobenzyl)‐5‐methoxy‐2‐methyl‐3‐indole acetic acid] (0.1–1.0 mM). Concurrently, indomethacin enhances the lipolysis of membrane phospholipid containing arachidonic acid but has no effect on the rate of O2 uptake in these samples. The system generates a rapidly developed chemiluminescense (CL), the intensity and rate of development of which are related to indomethacin concentration. The microsomal CL generated in the presence of indomethacin is distinct from the previously reported CL in that the time required for maximum intensity development is a matter of seconds (20–180) rather than hours. The enhanced CL is believed to be due to an energy transfer reaction whereby a high energy species transfers energy to the indomethacin molecule, which, in turn, decays via chemiluminescense. An enhanced chemiluminescense was also observed when indomethacin was added to a lipoxidase system and superoxide generating system (xanthine oxidase). Based on inhibitor studies, the rapidly developed chemiluminescense of the microsomal system requires cytochrome P‐450 in addition to NADPH and coordinated iron ions. The results indicate that the CL is related to neither hydroxyl free radical nor superoxide anion formation.
The content and composition of sterols and sterol esters in low erucic acid rapeseed (Brassica napus)
Authors: Johansson Anna , Appelqvist Lars‐Åke 
Published: November 2006

AbstractThe low temperature crystallization technique for the enrichment of “minor” components, such as sterols and sterol esters, from vegetable oils was applied to low erucic acid rapeseed oils. The recovery of free sterols and sterol esters was estimated by use of14C‐cholesterol and14C‐cholesterol oleate. 80% of the free sterols and 45% of the sterol esters were recovered in the liquid fraction, while in two studies total recoveries were 95% and 99%, respectively. This technique showed some selectivity toward the sterol bound fatty acids when compared to direct preparative thin layer chromatography (TLC) of the crude oil. Gas liquid chromatography (GLC) analysis of the free and esterified sterols as TMS‐derivatives showed very little selectivity in the enrichment procedure. The fatty acid patterns of the sterol esters demonstrated, however, a preference in the liquid fraction for those sterol esters which have a high linoleic and linolenic acid content. The content of free sterols was 0.3–0.4% and that of sterol esters 0.7–1.2% of the rapeseed oils in both winter and summer types of low erucic acid rapeseed (Brassica napus) when the lipid classes were isolated by direct preparative TLC of the oils. The free sterols in the seven cultivars or breeding lines analyzed were composed of 44–55% sitosterol, 27–36% campesterol, 17–21% brassicasterol, and a trace of cholesterol. The esterified sterols were 47–57% sitosterol, 36–44% campesterol, 6–9% brassicasterol, and traces of cholesterol and Δ5‐avenasterol. The fatty acid patterns of these esters were characterized by ca. 30% oleic acid and ca. 50% linoleic acid, whereas these acids constitute 60% and 20%, respectively, of the total fatty acids in the oil. Little or no variation in sterol and sterol ester patterns with locality within Sweden was observed for the one cultivar of summer rapeseed investigated by the low temperature crystallization technique.
Composition of lipids of bovine optic nerve
Authors: Das S. K. , Steen M. E. , McCullough M. S. , Bhattacharyya D. K. 
Published: November 2006

AbstractLipids from bovine optic nerve were analyzed. The total content of 16.5% by weight included 27.2% nonpolar lipids, 26.1% glycolipids, and 46.7% phospholipids by weight. Free cholesterol was the major component of the nonpolar lipid fraction. The cerebrosides, 73.5% of total glycolipids, were separated by thin layer chromatography (TLC) into two bands (upper and lower) that were present in equal proportion. Cerebroside sulfates comprised about 27.5% of total glycolipids. Gangliosides were also detected in the glycolipid fraction. In order of predominance, choline glycerophospholipids, ethanolamine glycerophospholipids, ethanolamine plasmalogens, serine glycerophospholipids, sphingomyelins, and inositol glycerophospholipids were the major phospholipids. Palmitoyl (16∶0), stearoyl (18∶0), and oleoyl (18∶1) groups were the major acyl groups in all neutral and phospholipid classes. However, ethanolamine glycerophospholipids, serine glycerophospholipids, and inositol glycerophospholipids contained a large percentage of 22∶6 (docosahexaenoyl) group. The major alk‐1‐enyl groups of the plasmalogens were 16∶0, 18∶0, and 18∶1. Steroyl (18∶0), lignoceroyl (24∶0), and nervonoyl (24∶1) were the major acyl groups in all sphingolipids. Lower cerebroside band and cerebroside sulfates contained large amount of hydroxylignoceroyl (cerebronoyl) and hydroxynervonoyl groups.
The steric requirements for sterol inhibition of tetrahymanol biosynthesis
Authors: Conner Robert L. , Landrey Josephine R. , Joseph John M. , Nes William R. 
Published: November 2006

AbstractMany naturally occurring sterols are accumulated and metabolized byTetrahymena pyriformis. In most cases, the sterols are desaturated to giveΔ5,7,22‐derivatives. Compounds with an ethyl, but not with a methyl, substituent at C‐24 are dealkylated. Exposure of the ciliates to the appropriate sterol sharply curtails the synthesis of the native pentacyclic triterpenoid alcohols, tetrahymanol and diplopterol. An analysis with modified sterols has revealed several additional features that are required for desaturation at C‐7,8 and C‐22,23 and for inhibition of tetrahymanol biosynthesis. The presence of atrans‐17(20)‐double bond, which eliminates free rotation at C‐20 and fixes C‐22 to the right of the nucleus, does not interfere with desaturation, while thecis‐ or left‐handed isomer is not metabolized. Thecis‐Δ17(20)‐isomer is, however, an effective inhibitor of tetrahymanol biosynthesis, although less so that thetrans‐counterpart. When a methyl or hydroxyl group at C‐20 protrudes to the front of the molecule in the right‐handed conformation, metabolism is reduced or abolished. Shortening (by one C‐atom) or lengthening of the sterol side chain has little effect on the ability of the compounds to inhibit tetrahymanol biosynthesis or to support growth, as long as the overall length of the side chain does not exceed seven carbons from C‐20. The presence of a 7α‐, 7β‐, 20α‐, 20β‐, or a 25‐hydroxy group in the cholesterol molecule sharply inhibits desaturation and curtails the effectiveness of the compound as an inhibitor of tetrahymanol biosynthesis. The 7‐ or 22‐keto derivatives seem to act in a fashion similar to the hydroxy derivatives, but these compounds show greater inhibition of growth. 20‐Methylcholesterol, however, is a potent inhibitor of synthesis, which suggests that the polarity of the substituent of C‐20 is more important than bulk. Many sterols can effectively replace tetrahymanol in the membranes of these ciliates. However, several of the compounds, which inhibit synthesis, appear to be physiologically inappropriate, and poor growth results. An example of the latter class is 20‐methylcholesterol. Finally, a class of sterols, represented by 20α‐hydroxycholesterol and 7‐ketocholesterol, does not severly inhibit tetrahymanol synthesis but leads to growth inhibition and surface abnormalities. These sterols apparently lead to a disordered membrane, even in the presence of tetrahymanol.
Inhibition of cholesterol synthesis by oxygenated sterols
Authors: Kandutsch Andrew A. , Chen Harry W. 
Published: November 2006

AbstractSterols derived from cholesterol by introducing a ketone or hydroxyl function in the 6, 7, 15, 20, 22, 24, or 25 positions are known to be potent inhibitors of sterol synthesis in cell cultures. To gain more information regarding structural requirements for inhibitory activity, inhibitory potencies were determined for a series of 18 C27‐steroids with various combinations of ketone and hydroxyl functions substituted in positions 3, 4, 5, 6, and 7, or with a single ketone or hydroxyl function in one of these positions. The effects of nuclear double bonds upon inhibitory activity were also examined. A ketone or hydroxyl function in position 3 and a second ketone or hydroxyl function in position 6 or 7 was required for inhibitory activity with two kinds of cell culture. A 3β5α6β‐triol was not more inhibitory than a comparable 3β,6β‐diol. Cholestance‐3β 5α‐diol inhibited sterol synthesis in L cells but not in liver cell cultures. The inhibitory activities of 7‐oxygenated sterols were not markedly affected by the presence of a double bond in position 4 or 5. Current knowledge of the mechanism through which the oxygenated sterols suppress cholesterol synthesis is reviewed.
Cyclopamine and related steroidal alkaloid teratogens: Their occurrence, structural relationship, and biologic effects
Authors: Keeler Richard F. 
Published: November 2006

AbstractA spontaneous congenital deformity is produced in lambs whose dams consumeVeratrum californicum on the 14th day of gestation. The deformity is generally expressed as cyclopia, cebocephaly, anophthalmia, or microphthalmia. This teratogenic effect is produced by certain steroidal alkaloid teratogens from the plant—most notably the compound cyclopamine. Cyclopamine is a C‐nor‐D‐homo steroid with fused furanopiperidine rings E and F at right angles to the plane of the steroid because of spiro attachment at C‐17 of the steroid. Among veratrum alkaloids, only those with an intact furan ring E were teratogenic in sheep, whereas those in which the piperidine ring is not rigidly positioned at right angles to the steroid were not. Many ruminants and laboratory animals are susceptible to the teratogen. It has wide species and tissue specificity and appears to have a direct effect on the embryo, not as a consequence of metabolic alteration of its structure nor as an indirect effect through a maternal influence. Other plant sources, notably potatoes, tomatoes, and eggplant contain related spirosolane steroidal alkaloids. Among naturally occurring spirosolanes, solasodine is teratogenic in hamsters, but neither tomatidine not diosgenin, the non‐nitrogen containing analog of solasodine, is teratogenic. Results of these and other studies suggest that a basic nitrogen positioned α with respect to the steroidal plane and at appropriate distance beyond the D ring confers the teratogenicity on the molecule. Potato sprouts with high alkaloid content are teratogenic in hamsters, but tubers and peels are not.
Metabolism of ether linked glycerolipids in dogfish (Squalus acanthias) serum: Evidence for resistance of ether bond to cleavage in 1‐alkyl‐2,3‐diacylglycerols
Authors: Malins Donald C. , Robisch Paul A. 
Published: November 2006

AbstractRac‐[1‐14C]‐palmitylglycerol (chimyl alcohol), rac‐[1‐14C]‐palmityl‐2,3‐dioleoylglycerol, and rac‐palmityl‐2,3‐[9, 10‐3H]‐dioleoylglycerol were incubated with dogfish (Squalus acanthias) serum for periods of up to 15.0 hr. The ether bond of the carbon 14 labeled chimyl alcohol was cleaved readily, and radioactivity was incorporated into free fatty acids and the acyl chains of the major glycerolipids of the serum. In sharp contrast, the ether bond of the corresponding dioleoyl derivative remained virtually intact. However, the tritium from the acyl chains was incorporated into glycerolipids via intermolecular rearrangements of fatty acids. The findings are consistent with previous findings with rat liver microsomes showing that the ether linkages of alkylglycerolipids are resistant to oxidative cleavage when acyl groups are present on the glycerol moiety. However, substantial differences may exist between the conditions required for oxidative cleavage of the ether linkage of alkylglycerols in mammals and primative fish.
Studies of serum lecithin‐cholesterol acyl transferase activity in rat: Effect of vitamin E deficiency, oxidized dietary fat, or intravenous administration of ozondies or hydroperoxides
Authors: Takatori Takehiko , Privett O. S. 
Published: November 2006

AbstractSerum lecithin‐cholesterol acyl transferase activity in the rat was studied in animals raised on diets devoid of vitamin E or containing oxidized fat and in the serum of normal animals after intravenous administration of hydroperoxides or ozonides. Lecithin‐cholesterol acyl transferase activity was suppressed by a vitamin E deficiency but was elevated in the serum of the animals fed diets containing oxidized fat. The intravenous injection of hydroperoxides or ozonides of linoleate into the tail vein of rats caused an immediate depression of serum lecithin‐cholesterol acyl transferase activity. The effect of hydroperoxides was more severe than the ozonides, but, with sublethal doses of these compounds, the activity of the enzyme became normal within 24 hr. Hydroperoxides and ozonides also suppressed the activity of lecithin‐cholesterol transferase of rat serum of normal animals in vitro. The suppression of lecithin‐cholesterol acyl transferase activity by hydroperoxides of ozonides was only partially restored by the addition to the serum of 2‐mercaptoethanol.
Rapid enzyme‐induced hydrolysis of microgram amounts of phosphatidylcholine on phospholipase A2/celite columns
Authors: Marmer William N. , Pietruszka Kathleen A. 
Published: November 2006

AbstractA method has been developed to hydrolyze microgram amounts of phosphatidylcholine (PC) regiospecifically. Hydrolysis of thesn‐glycerol 2‐acyl group occurs rapidly on microcolumns of immobilized phospholipase A2 on Celite 545 diatomaceous earth. Close to 90% reaction occurs within the first 5 min. Acyl group analysis then may be accomplished by gas liquid chromatography (GLC) of the resulting fatty acids. Hydrolysis of α‐16∶0‐β‐14∶0 PC demonstrated consistent selectivity for 14∶0 liberation, with small amounts of 16∶0 probably indicative of acyl scrambling during the synthesis of the PC. Hydrolysis of an equal weight mixture of (14∶0)2 PC and (18∶2)2PC demonstrated nonpartiality of the immobilized enzyme for either a saturated or unsaturated substrate. The new methodology offers a convenient and sensitive alternative to the presently used procedures.
The occurrence of a furanoid fatty acid inHevea brasiliensis latex
Authors: Hasma H. , Subramaniam A. 
Published: November 2006

AbstractMethyl esters from the triglyceride fraction of the neutral lipids of natural rubber latex were found by gas liquid chromatography to contain about 90% of a furanoid acid. Spectroscopic analysis identified the acid as 10,13‐epoxy‐11‐methyloctadeca‐10,12‐dienoic acid.
Separation of sulfated bile acids by high‐performance liquid chromatography
Authors: Goto Junichi , Kato Hiroaki , Nambara Toshio 
Published: November 2006

AbstractIn order to establish a new method for simultaneous determination of sulfated bile acids without deconjugation, separation of 3‐sulfates of unconjugated, glyco‐ and tauroconjugated bile acids by high‐performance liquid chromatography has been undertaken. The preliminary experiment indicated that reversed phase chromatography on an ODS SC‐02 column using ammonium carbonate aqueous solution/acetonitrile as a mobile phase would be promising. The ratio of peak width to retention time was varied depending upon the salt concentration. The content of water in mobile phase exerted an influence on the capacity ratio to a certain extent, but not on the resolution. The use of 0.5% ammonium carbonate/acetonitrile (26∶8 and 20∶8, v/v) was found to be suitable for complete resolution of sulfated cholate, chenodeoxycholate, deoxycholate, lithocholate and their glyco‐ and tauro‐conjugates.
Interaction of plasma high density lipoprotein HDL2b (d 1.063–1.100 g/ml) with single‐bilayer liposomes of dimyristoylphosphatidylcholine
Authors: Nichols Alex V. , Gong Elaine L. , Forte Trudy M. , Blanche Patricia J. 
Published: November 2006

AbstractIncubation of a major subfraction, HDL2b (d 1.063–1.100 g/ml), of human plasma high density lipoproteins, HDL (d 1.063–1.21 g/ml), with single‐bilayer liposomes of dimyristoylphosphatidylcholine (DMPC) resulted in uptake of DMPC by the HDL2b and dissociation of lipid‐free apolipoprotein A‐I (apoA‐I). In the presence of excess DMPC, the dissociated apoA‐I was also incorporated with DMPC into discoidal complexes. Preliminary studies with model apoA‐I‐DMPC complexes indicated that they also can interact with native HDL2b with the resultant transfer of their DMPC to HDL2b and the concomitant release of their apoA‐I. After interaction of HDL2b with DMPC liposomes, the DMPC‐enriched HDL2b product showed a lower hydrated density and a larger particle size than the control HDL2b. The molecular properties of the lipoprotein product suggest that stabilization of the apoA‐I‐depleted HDL2b probably occurred via substitution of DMPC for the apoA‐I at the HDL2b surface rather than by fusion of the apoA‐I‐depleted HDL2b. The above interactions of HDL2b with single‐bilayer liposomes and discoidal complexes indicate pathways of phospholipid transfer relevant to the possible role of HDL in the metabolism of lipoprotein surface components in vivo.
Biosynthesis of chenodeoxycholic acid: Side‐chain hydroxylation of 5β‐cholestane‐3α,7α‐diol by subcellular fractions of guinea pig liver
Authors: Hoshita N. , Shefer S. , Cheng F. W. , Dayal B. , Batta A. K. , Tint G. S. , Salen G. , Mosbach E. H. 
Published: November 2006

AbstractSide‐chain hydroxylation of 5β‐cholestane‐3α,7α diol was studied in subcellular fractions of guinea pig liver. The purity of the microsomal and the mitochondrial fractions was determined with marker enzymes, and relatively little cross contamination between the particulate fractions was detected. Methods for the analysis of the incubation mixture by thin‐layer chromatography and gas‐chromatography‐mass spectrometry were developed. Optimal assay conditions were established for the major hydroxylation reactions, namely the mitochondrial 26‐hydroxylation and the microsomal 25‐hydroxylation. It was found that the most active side‐chain hydroxylation in the guinea pig was the microsomal 25‐hydroxylation. The mitochondrial ω‐hydroxylation was stereospecific, in that the rate of formation of (25R)‐5β‐cholestane‐3α,7α,26‐triol was 8 times greater than that of the 25S isomer. The microsomal “26”‐hydroxylation was not stereospecific under the conditions employed. It is concluded that the mitochondrial “26” hydroxylation (leading to the formation of (25R)‐5β‐cholestane‐3α,7α,26‐triol) plays an important role in the biosynthesis of chenodeoxycholic acid. The participation of microsomal 25‐hydroxylation in the formation of chenodeoxycholic acids requires further investigation.
Dietary polyunsaturated fat versus saturated fat in relation to mammary carcinogenesis
Authors: Carroll K. K. , Hopkins G. J. 
Published: November 2006

AbstractHigh levels of dietary fat have been shown to promote the development of mammary tumors induced in rats by 7,12‐dimethylbenz(α)anthracene, and polyunsaturated fats were found to be more effective than saturated fats. In further studies it was found that diets containing 3% sunflowerseed oil (polyunsaturated fat) and 17% beef tallow or coconut oil (saturated fats) enhance tumorigenesis as much as a diet containing 20% sunflowerseed oil. Rats on these diets developed at least twice as many tumors as those fed diets containing either 3% sunflowerseed oil or 20% of the saturated fats alone. These results are in accord with human epidemiological data which show that breast cancer mortality in different countries is positively correlated with total fat intake but not with intake of polyunsaturated fat. Total fat intake varies greatly in different countries, but most human diets probably contain levels of polyunsaturated fat at least equivalent to 3% sunflowerseed oil.