bluuebunny/crossref_metadata_2025_split huggingface dataset:
Purification of surfactant from lung washings and washings contaminated with blood constituents
Authors: Shelley Sue A. , Paciga June E. , Balis John U. 
Published: December 2006

AbstractA rapid and simple method capable of purifying surfactant from rabbit alveolar washings and from washings contaminated with serum has been developed. The sample, containing 16% NaBr, is placed beneath a two‐layer discontinuous gradient of NaBr. After centrifugation, the surfactant is found near the top of the gradient tube at a density of 1.085 at 4 C while the contaminating material remains near the bottom. The lipid composition of surfactant from lung washings of normal animals isolated by this method compares quite favorably with surfactant isolated by much more elaborate and time consuming methods. Surfactant purified from mixtures of3H‐palmitate labeled rabbit serum and lung washings (1.6 mg serum phospholipid: 1 mg washing phospholipid) contained less than 3% of the phospholipid radioactivity. The phospholipid composition of this band was quite similar to that of surfactant from normal lung washings, but the protein content was much higher. A second density gradient centrifugation removed 90% of this protein resulting in a surfactant fraction with a phospholipid to protein ratio similar to that of surfactant from normal lung washings. These findings demonstrate that this purification method is capable of removing a large proportion of both serum phospholipids and proteins from lung washings contaminated with serum, making this method uniquely suitable for evaluation of surfactant in pathologic conditions of the lung.
Chaulmoogric acid: Assimilation into the complex lipids of mycobacteria
Authors: Cabot Myles C. , Goucher Charles R. 
Published: December 2006

AbstractLipid analysis ofMycobacterium vaccae, grown in the presence of chaulmoogric acid, demonstrates that this cyclopentenyl fatty acid is taken up by the organism and incorporated into cellular phospholipids and triacylglycerols. As cell growth is retarded by the addition of chaulmoorgric acid to the growth medium, it is possible that the antimicrobial properties of this compound result from a perturbation of membrane processes.
Stimulation of bile acid synthesis by dibutyryl cyclic AMP in isolated rat hepatocytes
Authors: Sundaram G. S. , Rothman Vicki , Margolis Simeon 
Published: December 2006

AbstractFreshly isolated rat hepatocytes were used to examine the effects of dibutyryl cyclic AMP on the incorporation of14C‐acetate and14C‐cholesterol into bile acids. After an initial lag period, both precursors were incorporated into cholic and chenodeoxycholic acids at a linear rate for the subsequent 60 min. An apparent stimulation of bile acid formation from14C‐acetate by dibutyryl cyclic AMP was complicated by the concomitant inhibition of cholesterol synthesis. In experiments with14C‐cholesterol, dibutyryl cyclic AMP (1 mM) increased the labeled cholic and chenodeoxycholic acids in the medium by 83 and 224%, respectively, but cellular levels of labeled bile acids were unchanged. As a result, the nucleotide stimulated the overall incorporation of14C‐cholesterol into cholic acid by 39% and into chenodeoxycholic acid by 123%. The mean ratio of labeled cholic to chenodeoxycholic acid declined from 55∶45 in control cells to 41∶59 in cells incubated with dibutyryl cyclic AMP. The results demonstrate that label incorporation can be used to study the regulation of bile acid synthesis in isolated hepatocytes. We propose that dibutyryl cyclic AMP enhances bile acid production by phosphorylating, and thus stimulating the activity of, cholesterol 7α‐hydroxylase, the rate‐limiting enzyme in bile acid synthesis.
Hypercholesterolemia in rats fed cholesterol in agar gel diets
Authors: Erdman John W. , O'Reilly Thomas C. 
Published: December 2006

AbstractFemale (Exp. I) or male (Exp. II) weanling rats were fed diets containing either 2% Solka‐Floc or 2% agar for 28‐day periods. Some groups received 1% cholesterol, either added in crystalline form or first dispersed in the oil portion of the diet, and some agar groups received their diet in a gelled form. Feces were collected for a 3‐day period after 2 weeks (Exp. II) or during the fourth week (Exp. I) of experimentation. Serum and liver cholesterol, total liver lipids, fecal lipids, and fecal sterols were determined. The results indicated that cholesterol feeding increased serum cholesterol, total liver, and fecal lipids, liver cholesterol, and fecal sterols. Substitution of agar for Solka‐Floc in dry (nongelled) diets further increased total liver lipids (Exp. I), but had no significant effect upon any other measured parameter. Gelling of 1% cholesterol agar diets, in contrast to the 1% cholesterol dry agar diet, resulted in reduced liver cholesterol in both experiments. Gelling significantly increased fecal sterols after 2 weeks feeding (Exp. II), but no significant differences were observed after 4 weeks feeding (Exp. I) when compared to 1% cholesterol‐fed groups. Small, nonsignificant increases of liver cholesterol and total liver lipids with similar reduction of fecal sterols resulted from dispersing the cholesterol in the oil portion of the diet prior to mixing. The results indicate that (a) inclusion of 2% agar in rat diets and (b) dispersing cholesterol in oil had little effect upon serum, liver, or fecal lipids in cholesterol‐fed rats. However, gelling the agar diets reduced liver cholesterol, possibly by initial reduction of dietary cholesterol absorption.
The transfer of free palmitic and linoleic acids across the ovine placenta
Authors: Noble R. C. , Shand J. H. , Bell A. W. , Thompson G. E. , Moore J. H. 
Published: December 2006

AbstractFollowing the injection of3H‐16∶0 and14C‐18∶2 (n−6) into the jugular vein of the ewe, the rates of disappearance of these fatty acids from the maternal plasma and their rates of appearance in the fetal plasma have been studied. The rates of disappearance of both labeled acids from the maternal circulation were similar. The appearance of radioactivity in the fetal plasma was rapid and could be detected within 2.5 min after injection into the mother. In contrast to the similar rates of disappearance of the fatty acids from the maternal plasma, the rate of accumulation of3H‐16∶0 within the fetal plasma was appreciably greater than that of14C‐18∶2 (n−6). The absolute concentrations of the total lipid and unesterified fatty acid fractions within the fetal plasma were significantly lower than that of the maternal plasma. In comparison to that of maternal plasma, fetal plasma lipid contained an extremely low proportion of 18∶2 (n−6) accompanied by an appreciable accumulation of 20∶3 (n−9). On the other hand, the proportion of 20∶4 (n−6) within the fetal plasma was about twice that present within the maternal plasma. The obvious inability of the placenta to be as freely permeable to the passage of 18∶2 (n−6) as to 16∶0 is discussed in relation to these differences in fatty acid composition between the maternal and fetal plasmas and the known poor essential fatty acid status of the developing fetus.
Analysis of alpha tocopherol in blood plasma and platelets by gas liquid chromatography
Authors: Lehmann Joanna 
Published: December 2006

AbstractA method is described for the analysis of α‐tocopherol by gas liquid chromatography (GLC) with 0.3% Apiezon L as liquid phase. Impurities that interfere with GLC are removed by saponification. Cholesterol and other nonsaponifiables are separated from α‐tocopherol by GLC.
17Z‐Tetracosenyl 1‐glycerol ether from the spongesCinachyra alloclada andUlosa ruetzleri
Authors: Cardellina John H. , Graden Clinton J. , Greer Bradley J. , Kern John R. 
Published: December 2006

AbstractThe 1‐glycerol ether of 17Z‐tetracosenol has been identified as a major constituent of the dichloromethanesoluble extracts of two marine sponges,Cinachyra alloclada andUlosa ruetzleri. Spectral analysis and chemical degradations led to the assigned structure. Batyl alcohol was also found, in lesser quantities, inU. ruetzleri, but not inC. alloclada.
Different fatty chain compositions of alkenylacyl, alkylacyl and diacyl phospholipids in rabbit alveolar macrophages: High amounts of arachidonic acid in ether phospholipids
Authors: Sugiura Takayuki , Nakajima Motoko , Sekiguchi Nobuyuki , Nakagawa Yasuhito , Waku Keizo 
Published: December 2006

AbstractHigh levels of ether phospholipids were found in rabbit alveolar macrophages. Choline phosphoglycerides (CPG) contained a significant amount of alkylacyl compound (32.5%). On the other hand, ethanolamine phosphoglyceride (EPG) included a very large amount of alkenylacyl compounds (61.2%). Small amounts of alkenylacyl CPG and alkylacyl EPG were also observed. The occurrence of a high amount of alkylacyl CPG may be related to the synthesis or release of platelet‐activating factor (PAF) from macrophages. Fatty chains at the 1‐ and 2‐positions in each lipid class of CPG or CPG or alkenylacyl EPG were several other. Particularly, the levels of 20∶4 (arachidonic acid) in alkylacyl CPG or alkenylacyl EPG were several times higher than those in corresponding diacyl phospholipids. Large portions of 20∶4‐containing species have alkenyl or alkyl ether moieties at their 1‐position in both CPG (73.6%) and EPG (85.9%). These results suggest the importance of ether‐containing phospholipids in rabbit alveolar macrophages.
Cholesteryl ester transfer protein inhibition by PD 140195
Authors: Bisgaier Charles L. , Essenburg Arnold D. , Minton Laura L. , Homan Reynold , Blankley C. John , White Andrew 
Published: December 2006

AbstractThe presence of plasma cholesteryl ester transfer protein (CETP) activity may be atherogenic, and, therefore, strategies to inhibit its activity or production may result in a beneficial effect on lipoprotein profiles and the disease process. The current report describes 4‐phenyl‐5‐tridecyl‐4H‐1,2,4‐triazole‐3‐thiol (PD 140195), a novel CETP inhibitor. The concentration‐dependent inhibition of CETP by PD 140195 and the inhibitory monoclonal antibody (Mab) TP2 is demonstrated in a variety ofin vitro assay systems. Molecular models of PD140195 suggest a spatial mimicry of the cholesteryl ester structure. Despite the structural similarity, kinetic studies with a fluorescent cholesteryl ester analog suggest that the inhibition of transfer is not competitive. PD 140195 also selectively inhibited cholesteryl ester but not triglyceride transfer, while the Mab TP2 blocked CETP transfer of both. Studies were carried out to determine whether CETP inhibition observedin vitro could also be demonstratedin vivo. When PD 140195 was intravenously infused to anesthetized rabbits (up to 20 mg/kg), only transient CETP inhibition was observed.In vitro reconstitution studies in the presence of bovine serum albumin resulted in marked reduction of PD 140195 inhibitory activity. Thus, the low activity of PD 140195 in whole plasma probably results from binding to other plasma proteins.
The lipids of slugs and snails: Evolution, diet and biosynthesis
Authors: Zhu Ning , Dai Xiaonan , Lin Don S. , Connor William E. 
Published: December 2006

AbstractThere is a considerable gap in current knowledge of the lipid composition of snails and slugs, both of which belong to the phylum Mollusca. We have therefore analyzed the sterol and fatty acid compositions of three species of slugs and three species of snails. The sterols of slugs included eight different sterols: cholesterol contributed 76–85% of the total sterols, brassicasterol accounted for 4–13%; other sterols we identified were lathosterol, 24‐methylene cholesterol, campesterol, stigmasterol, sitosterol and sitostanol. In contrast, snails contained two additional sterols, desmosterol and cholestanol. Of the polyunsaturated fatty acids in slugs, linoleic (18∶2n−6) and arachidonic acids (20∶4n−6) were the major n−6 fatty acids, while linolenic (18∶3n−3) and eicosapentaenoic acids (20∶5n−3) were the predominant n−3 fatty acids. Docosahexaenoic acid (22∶6n−3), the end product in the n−3 fatty acid synthetic pathway and an important membrane fatty acid of mammals, fish and birds, was absent in both slugs and snails. However, the analogous product of n−6 fatty acid synthesis, 22∶5n−6, was found in both snails and slugs. This raises speculation about preference for n−6 fatty acid synthesis in these species. Our data show the unique sterol and fatty acid compositions of slugs and snails, as well as similarities and differences in sterol composition between the two. The results between the two land mollusks are contrasted with those of marine mollusks, such as oysters, clams and scallops.
A method of ultraviolet spectrophotometry of lipid monolayers on silica gel
Authors: Porter W. L. , Henick A. S. , Jeffers J. I. , Levasseur L. A. 
Published: December 2006

AbstractA method has been developed for visible and UV spectrophotometry of lipid monolayers after preadsorption on silica gel from solution in hydrocarbon solvents. Lipid‐coated silica gel is made optically transparent in the desired spectral region by slurrying with an inert solvent mixture. Reproducible gels with nearly the same refractive index as the solvent are achieved by careful choice of mixed solvents and carefully timed settling periods. The gel is pipetted into a silica cuvette of 1 cm light path, and a 9 mm silica spacer bar is inserted between Teflon guide strips. Appropriate choice of solvent mixtures (mainly spectral grade cyclohexane and cyclooctane) permits quantitation of spectra down to 2250 Angstrom units, using a silica gel reference cell. Lipid elution from the monolayer into the solvent is usually less than 1% at the dry‐mixing dilutions used. Spectra of known unsaturated carbonyl compounds adsorbed on silica show red shifts as great as 240 Angstrom units, while blue shifts as great as 100 Angstrom units are observed for tocopherol derivatives with an intact aromatic ring. Very small shifts are observed for polyenes. The extent and direction of the shifts are indicative of adsorption and its orientation and are useful in the preliminary determination of the class of an unknown compound. The silica slurry spectra of the important tocopherol oxidation products, the quinone, dimer and trimer, have been examined. Peak wavelength shifts are consistent with structures elsewhere proposed for these compounds.
Inhibition of cholesterol and fatty acid biosynthesis in liver enzymes and chicken hepatocytes by polar fractions of garlic,
Authors: Qureshi Asaf A. , Abuirmeileh Naji , Din Zafeer Z. , Elson Charles E. , Burger Warren C. 
Published: December 2006

AbstractDifferent concentrations of polar fractions, methanol‐soluble (MESF), or water‐soluble (WASF), of 1–8% equivalent to fresh garlic paste were added to yellow corn‐soybean based diets and fed to 5‐week‐old male broiler chickens for 3 weeks to measure the inhibition of hepatic β‐hydroxy‐β‐methylglutaryl coenzyme A (HMG‐CoA) reductase, cholesterol 7α‐hydroxylase (7α‐hydroxy) and fatty acid synthetase (FAS). Dose‐related decreases in the activities of these enzymes were obtained. Decreases in serum total cholesterol and in low density lipoprotein (LDL) levels were also observed. There was no effect on the level of cholesterol in high density lipoprotein (HDL). The most effective dose for these decreases was found 0.54% (MESF) and 1.2% (WASF) equivalent to 6% of the fresh garlic. The inhibition of HMG‐CoA reductase and FAS by 25–300 μm of MESF or WASF for 15 min was tested in vitro, in male and female chicken hepatocytes. Inhibitions of activity were dose‐dependent and the degree of inhibition increased with duration of incubation (150 μg of MESF or WASF 5 to 60 min). Dietary supplementation of odorless WASF of garlic was found to be very effective in lowering the total and LDL cholesterol levels compared to control chickens.
Analysis of autoxidized fats by gas chromatography‐mass spectrometry: VIII. Volatile thermal decomposition products of hydroperoxy cyclic peroxides
Authors: Frankel Edwin N. , Neff William E. , Selke Edward 
Published: December 2006

AbstractSecondary oxidation products are important sources of volatiles because of their susceptibility to further decomposition. Volatiles from the thermal decomposition of hydroperoxy cyclic peroxides have been identified by capillary gas chromatography followed by mass spectrometry (GC‐MS). By using a saturated hydroperoxy cyclic peroxide as a synthetic model, the thermal decomposition pathways have been elucidated. Main cleavage occurs between the peroxide ring and the carbon‐bearing hydroperoxide group. Volatiles produced were generally similar to those from corresponding monohydroperoxides. New volatiles identified included methyl furan octanoate, methyl ketones, and conjugated diunsaturated aldehyde esters. The general fragmentation observed between the peroxide ring and the hydroperoxide‐bearing carbons is sufficiently predictable that it can be used as a tool for the structural characterization of hydroperoxy cyclic peroxides. Hydroperoxy cyclic peroxides from autoxidized and photosensitized oxidized methyl linolenate are suggested as important precursors of volatiles that may affect flavor quality of lipid‐containing foods.
Effects of dietaryTrans‐fat on biliary and fecal steroid excretion and serum lipoproteins in rats
Authors: Sugano Michihiro , Watanabe Midori , Kohno Mitsuko , Cho Young J. , Ide Takashi 
Published: December 2006

AbstractRats were fed cholesterol‐free or cholesterol‐enriched diets containing olive oil or partially hydrogenated corn oil at the 10% level for ca. 30 days (c‐18∶1, 77.0% in the former diet andc‐18∶1, 24.7% andt‐18∶1, 42.5% in the latter). The linoleic acid content of these fat diets was made equivalent (1.7 energy%). After feeding cholesterol‐free diets,trans fat compared tocis fat showed(a) no untoward effects on growth parameters, (b) a reduction of serum cholesterol levels without influencing concentrations of serum apolipoproteins A‐I, B and E, (c) no effects on the bile flow and the concentration of biliary cholesterol and bile acids, (d) an increasing trend of fecal excretion of neutral and acidic steroids, both in terms of mg/day and mg/g feces, and (e) rather equivocal change in the composition of fecal, but not biliary steroids. Similar response patterns were also observed when cholesterol‐enriched diets were fed except for a decrease in serum apo B and an ineffectiveness to increase fecal acidic steroids. Together with the results obtained from experiments simultaneously performed with safflower oil and completely hydrogenated corn oil, it seems that the steroid metabolism can be specificallymodified by the geometry of dietary fats.
The biosynthesis of cholesterol and other sterols by brain tissue: II. A comparison of in vitro and in vivo methods
Authors: Ramsey R. B. , Jones J. P. , Naqvi S. H. M. , Nicholas H. J. 
Published: December 2006

AbstractWhen microsomal + soluble preparations of adult or 15‐day‐old rat brains were incubated with 2‐14C‐mevalonic acid,14C‐squalene accumulated. A metabolic block at the squalene to cholesterol stage was indicated. This prompted a comparison of all methods currently used to study cholesterol biosynthesis by brain tissue. Brain cell‐free preparations from newborn, 15‐day‐old or adult rats accumulated14C‐squalene in a similar manner, with either 2‐14C‐acetate or 2‐14C‐mevalonic acid as substrates. Homogenates and minced preparations from newborn or 15‐day‐old rats accumulated some 4,4‐dimethyl sterols, but considerable conversion to free 4‐desmethyl sterols (cholesterol) was evident. Sterol esters were also present in all the in vitro studies. In general, increased disruption of tissue resulted in decreased free 4‐desmethyl sterol formation in vitro. Intraperitoneal injection of labeled acetate or mevalonate to newborn or 15‐day‐old rats produced labeled brain 4‐desmethyl sterol with little accumulation of squalene or 4,4‐dimethyl sterols, but the yields in brain were small compared to total amount of labeled material administered. At all ages intracerebral injection produced the best yield of labeled cholesterol for the amount of nonsaponifiable material formed.
Detecting and managing an overgrazing‐drought synergism in the threatenedEcheveria longissima(Crassulaceae): the role of retrospective demographic analysis
Authors: Martorell Carlos 
Published: December 2006

AbstractEcheveria longissima, a threatened herb whose habitat has been severely overgrazed and eroded, was studied for three years in a currently grazed and a fenced area. Matrix population models were used to assess if livestock elimination provides a proper management strategy. The merits of retrospective perturbation analyses in terms of management planning have been debated. Nevertheless, they may prove useful when applied in combination with exclosures because they may detect the effects of anthropogenic disturbance on population dynamics. Thus, the results of retrospective and prospective methods were compared. A rapid decrease in population size was projected in both areas, even though it was faster in the exposed one. The demographic processes that were favourable or detrimental in a given year were magnified outside of the fence, but buffered in the exclosure, showing a strong drought‐disturbance synergism. Thus, the largest difference in the population growth rateλbetween areas was observed in the driest year. Higher nurse‐plant density inside the fence seems to alleviate drought effects. The use of prospective analysis alone may lead to erroneous management decisions, since the highest elasticities corresponded to transitions that were favoured by human activities. While allowing for an increasedλin the short term, intervention aimed at increasing these transitions further without attending others that are lessened by disturbance may introduce large changes in the population dynamics, with negative long‐term consequences. Retrospective methods can detect which processes have been altered by disturbance and its synergisms, so we may more efficiently restore healthy population dynamics.
Paternal ages below or above 35 years old are associated with a different risk of schizophrenia in the offspring
Authors: Wohl M. , Gorwood P. 
Published: December 2006

AbstractBackgroundA link between older age of fatherhood and an increased risk of schizophrenia was detected in 1958. Since then, 10 studies attempted to replicate this result with different methods, on samples with different origins, using different age classes. Defining a cut-off at which the risk is significantly increased in the offspring could have an important impact on public health.MethodsA meta-analysis (Meta Win®) was performed, assessing the mean effect size for each age class, taking into account the difference in age class references, and the study design.ResultsAn increased risk is detected when paternal age is below 20 (compared to 20–24), over 35 (compared to below 35), 39 (compared to less than 30), and 54 years old (compared to less than 25). Interestingly, 35 years appears nevertheless to be the lowest cut-off where the OR is always above 1, whatever the age class reference, and the smallest value where offspring of fathers below or above this age have a significantly different risk of schizophrenia.ConclusionNo threshold can be precisely defined, but convergent elements indicate ages below or above 35 years. Using homogeneous age ranges in future studies could help to clarify a precise threshold.