bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pulmonary surfactant lipid synthesis from ketone bodies, lactate and glucose in newborn rats
Authors: Sheehan Patricia M. , Yeh Yu‐Yan 
Published: November 2006

AbstractThe contribution of acetoacetate (AcAc), β‐hydroxybutyrate (βOHB), lactate and glucose to pulmonary surfactant lipid synthesis in three‐to five‐day‐old rats was measured. Minced lung tissue was incubated with3H2O and [3‐14C]AcAc, [3‐14C]βOHB, [U‐14C]lactate or [U‐14C]glucose, and the radioactivity incorporated into surfactant lipids was measured. When expressed as nmol of substrate incorporated/g lung tissue per four hr, lactate was incorporated more rapidly than other substrates into total surfactant lipids and phosphatidylcholine (PC). There was no difference in the rates of incorporation of lactate, AcAc or glucose into disaturated PC (DSPC). Substrates other than glucose were incorporated almost exclusively into fatty acids, whereas 60–80% of glucose incorporated into surfactant phospholipids was found in fatty acids, with the remaining in glyceride‐glycerol. When expressed as nmol acetyl units incorporated/g lung tissue per four hr, the rates of AcAc, lactate and glucose incorporation into total surfactant fatty acids were comparable. Glucose incorporation into DSPC and PC was greater than that of AcAc and lactate. When glucose was the only exogenous substrate added to the incubation medium, it contributed 37% of total surfactant fatty acids synthesized de novo. In the presence of other substrates, the contribution of glucose to de novo fatty acid synthesis dropped to 14–20%. In the presence of unlabeled glucose,14C‐labeled AcAc, lactate and βOHB contributed 52%, 40% and 19%, respectively, of the total fatty acids synthesized de novo. The rate of βOHB incorporation into surfactant lipids was only about 50% that of other substrates and was accompanied by low activity of β‐hydroxybutyrate dehydrogenase measured for newborn lung. These results demonstrate that AcAc and lactate are important precursors for surfactant lipids in neonatal rat lung.
Suppression by dexamethasone of isoproterenol‐mediated changes in fatty acyl‐CoA desaturase activity of Tetrahymena microsomes
Authors: Umeki Shigenobu , Nozawa Yoshinori 
Published: November 2006

AbstractPreincubation ofTetrahymena pyriformis cells with dexamethasone inhibited the microsomal fatty acyl‐CoA desaturase activities of isoproterenol‐induced modulation; that is, an increase in Δ9‐desaturase activity accompanied by a decrease in Δ12‐desaturase activity. Although isoproterenol caused an increase in Δ12‐terminal component activity with decreased Δ12‐terminal component activity, dexamethasone reduced these isoproterenol‐mediated activity changes. In cells treated with dexamethasone prior to isoproterenol administration, stimulation of cyclic AMP accumulation by isoproterenol was inhibited. These results suggest that dexamethasone may repress isoproterenol modulation of the activity of terminal components (cyanide‐sensitive factor) in the fatty acyl‐CoA desaturase system by reducing the cyclic AMP level.
Raman studies of structural rearrangements induced in human plasma lipoprotein carotenoids by malondialdehyde
Authors: Verma Surendra P. , Philippot Jean R. , Bonnet Bernard , Sainte‐Marie Josette , Moschetto Yves , Wallach Donald F. H. 
Published: November 2006

AbstractRaman and resonance Raman spectra of plasma lipoproteins ± malondialdehyde were studied at concentrations which block the normal receptor‐mediated uptake by cells. The strong resonance Raman bands at about 1010, 1162 and 1530 cm−1, due to the presence of carotenoids in the lipoproteins, are envisaged as structural probes. High resolution resonance Raman spectra of the 1500–1600 cm−1 region reveal multiple features suggesting the coexistence of several structural populations of β‐carotene whose precise assignment is complex. When plasma lipoproteins are reacted with malondialdehyde, a complex change occurs in the resonance Raman banding of β‐carotene in the 1500–1600 cm−1 region. Malonaldehyde (MDA) also modifies the acoustical region (70–200 cm−1 of low density lipoprotein (LDL) lipids. We suggest that malondialdehyde association with plasma lipoproteins alters the lipid structure via apoprotein or apoprotein/lipid associations.
Influence of hypo‐ and hyperthyroidism on rat liver glycerophospholipid metabolism
Authors: Dang An Q. , Faas Fred H. , Carter William J. 
Published: November 2006

AbstractThe effects of hyper‐ and hypothyroidism on enzyme activities involved in phospholipid metabolism in the rat liver were studied. Hyperthyroidism significantly decreases activities of both microsomal acyl‐CoA:glycero‐3‐phosphate acyltransferase (GPAT) (34%, p<0.01) and microsomal acyl‐CoA:1‐acylglycero‐3‐phosphocholine acyltransferase (GPCAT) (28–33%, p<0.01). This may contribute to the decreased proportions of certain unsaturated fatty acids found in microsomal phosphoglycerides in hyperthyroidism. Mitochondrial GPAT, phospholipase A2 and cytosol lysophospholipase are unaffected by hyperthyroidism. In contrast, hypothyroidism stimulates mitochondrial GPAT (38%, p<0.01) and microsomal GPCAT (14–19%) activities but decreases both mitochondrial phospholipase A2 (36%, p<0.01) and cytosol lysophospholipase (56%, p<0.01) activities. The increased GPCAT activity may contribute to the increased proportions of certain unsaturated fatty acids found in microsomal phosphoglycerides in hypothyroidism. Triiodothyronine (T3) treatment of the hypothyroid rat (25 μg/100 g body weight/day for four days) corrected phospholipase A2 and lysophospholipase activities to the level of the control rat, but failed to correct the increased mitochondrial GPAT activity and not only corrected but lowered GPCAT activity to the level of the hyperthyroid rat.
Thiobarbituric acid reaction of aldehydes and oxidized lipids in glacial acetic acid
Authors: Kosugi Hiroko , Kikugawa Kiyomi 
Published: November 2006

AbstractThiobarbituric acid (TBA) reaction of several aldehydes and oxidized lipids in glacial acetic acid was performed. All the samples were freely soluble in the solvent used. Saturated aldehydes produced a stable yellow pigment with an absorption maximum at 455 nm, a red pigment derived from malonaldehyde at 532 nm, and an orange pigment due to dienals at 495 nm. The absorbance maximum was 7–9 per μmol for saturated aldehydes, 27.5 per μmol for malonaldehyde and about 2 per μmol for dienals. Autoxidation of unoxidized lipids increased progressively in glacial acetic acid. When the TBA test was performed under nitrogen, autoxidation of unoxidized lipids was inhibited completely. While saturated aldehydes produced no yellow pigment under nitrogen, oxidized lipids produced a considerable amount of stable yellow pigment. The value for absorbance at 455 nm as a function of autoxidation time paralleled those of peroxide values. The absorbance of most oxidized lipids at 455 nm was higher than at 532 nm. Yellow pigment formation in the TBA test under nitrogen could not be ascribed to free saturated aldehydes but rather to unspecified closely related substances. The stable yellow pigment was found to be an excellent indicator of lipid oxidation.
Separation of isomeric lysophospholipids by reverse phase HPLC
Authors: Creer Michael H. , Gross Richard W. 
Published: November 2006

AbstractA reverse‐phase high performance liquid chromatography (HPLC) method was developed which resolved isomers of lysophosphatidylcholine (LPC) differing in the location of the aliphatic chain (sn‐1 orsn‐2 position) and the position (Δ6 or Δ9) or geometric configuration (cis ortrans) of the olefin group in monounsaturated species. LPC isomers containing an acyl substituent at thesn‐2 position eluted before their 1‐acyl‐sn‐glycero‐3‐phosphocholine (1‐acyl LPC) counterparts. The retention times of both thesn‐1 andsn‐2 isomers of monounsaturated species increased in the order Δ9‐cis < Δ9‐trans < Δ6‐cis. The integrated ultraviolet absorbance (203 nm) in binary mixtures of the Δ9‐cis and Δ6‐cis 2‐acyl lysophospholipid isomers correlated with the lipid phosphorus content of corresponding column eluates (r‐0.994). Thus, the present method will facilitate synthesis of isomerically pure diradylphospholipids by providing homogeneous lysophospholipid precursors and help simplify the quantitative analysis of unsaturated lysophospholipid species.
Highly saturated lipid composition of ctenophore cilia: Possible indication of low membrane permeability
Authors: Morris Robert J. , Bone Q. 
Published: November 2006

AbstractThe lipids of ciliary membranes in two species of ctenophore are found to be distinguished by phospholipids containing short chain saturated fatty acids and by saturated sterols. Such a composition is expected to result in a much lower permeability of cilia membranes to water and other ions than the general body membranes. We suggest that this is related to the large surface area of the cilia and is a requirement, on the part of the ctenophore, to control water and ionic fluxes across its surface membranes.
Lipid composition of liver mitochondria and microsomes in hyperthyroid rats
Authors: Ruggiero F. M. , Landriscina C. , Gnoni G. V. , Quagliariello E. 
Published: November 2006

AbstractTriiodothyronine‐induced alteration of the lipid pattern in rat‐liver mitochondria and microsomes has been investigated. In mitochondria, a 25% total cholesterol decrease and a 14% phospholipid increase have been detected. In these hyperthyroid rat liver organelles, a strong decrease in the total cholesterol/phospholipid molar ratio occurs. On the contrary, in microsomes from the same animals, a decrease of about 23% has been measured for both total cholesterol and phospholipids; hence, in this fraction, the total cholesterol/phospholipid molar ratio is unaffected by hyperthyroidism. The liver mitochondrial phospholipid composition, unlike the microsomal composition, is altered significantly in hyperthyroid rats; a 7.4% phosphatidylcholine decrease is accompanied by a similar additive percentage increase of both phosphatidylethanolamine and cardiolipin. In regard to total phospholipid fatty acid composition in liver microsomes from hyperthyroid rats, no variation has been observed compared with the control rats, whereas in mitochondria from the same animals, a meaningful linoleic acid decrease with a similar arachidonic acid increase has been found. In addition to fatty acid alteration, the separated mitochondrial phospholipid classes also exhibit some increase in stearic acid. Among phospholipids, cardiolipin changes the most of the esterified fatty acids in hyperthyroid rat liver. In this compound, a strong increase in the percentage of both palmitic and stearic acid and a 32.4% decrease of linoleic acid have been found.
Total gangliosides, ganglioside species and the activity of neuraminidase in different brain regions and spinal cord of normal and undernourished rats
Authors: Bhargava P. , Rao P. S. , Vajreshwari A. , Shankar R. 
Published: November 2006

AbstractTotal gangliosides, their concentrations and the distribution of individual ganglioside species were determined in the spinal cord, pons‐medulla, midbrain, cerebellum, hypothalamus, cerebral cortex, olfactory lobes and the rest of the forebrain, of 18‐ and 33‐day‐old normal and food‐restricted and rehabilitated rats. The activity of neuraminidase in the different regions of the brain and spinal cord was determined. Differences in total gangliosides as well as individual species in different regions of the brain were observed. Among brain regions, while total ganglioside content was significantly reduced in the case of the cerebellum, the hypothalamus was the most affected in the distribution of ganglioside species and the activity of neuraminidase was decreased. The significance of the distribution of ganglioside species in different brain regions in relation to the activity of neuraminidase is discussed.
Diurnal variation of plasma methyl sterols and cholesterol in the rat: Relation to hepatic cholesterol synthesis
Authors: Strandberg T. E. , Tilvis R. S. , Miettinen T. A. 
Published: November 2006

AbstractFree cholesterol of plasma low density lipoproteins (LDL) and high density lipoproteins (HDL) of the rat was high and that of plasma very low density lipoproteins (VLDL) was low during the dark period of the diurnal cycle. Variations in the esterified plasma sterols were inconsistent. Free methyl sterols were high in all lipoproteins during the dark phase. Simultaneously, the incorporation of14C‐acetate into nonsaponifiable sterols and the concentrations of free methyl sterols and cholesterol in the liver were elevated.
Effect of dietary fats on desaturase activities and the biosynthesis of fatty acids in rat‐liver microsomes
Authors: Mahfouz M. M. , Smith T. L. , Kummerow F. A. 
Published: November 2006

AbstractFour groups of rats were fed diets containing 15% (w/w) high‐oleic safflower oil (SFO, rich incis‐18∶1 acids), a mixture of 80% partially hydrogenated soybean oil plus 20% corn oil (H+CO, rich intrans‐18∶1 acids), lard (L, rich in saturated fatty acids) and corn oil (Co, rich in 18∶2ω6). Fatty acid composition of liver microsomes and activities of the Δ5, Δ6 and Δ9 desaturases were determined. Microsomal Δ6 desaturase activity and arachidonic acid were lower in the H+CO group compared with SFO of L. No difference was found in the Δ5 or Δ6 desaturase activity of CO and SFO groups. Thus, the oleic‐acid level of the SFO diet had no effect on the metabolism of 18∶2ω6. Fluorescent polarization studies, usingtrans‐parinaric acid as a probe, showed no differences between the physical states of phospholipid vesicles made from lipids isolated from each group. We concluded that thetrans‐18∶1 acids in partially hydrogenated soybean oil have a more inhibitory effect than saturated acids on EFA metabolism, even in the presence of adequate amounts of essential fatty acid.
Response ofDrosophila tocis‐ andtrans‐22‐dehydrocholesterol II. Ability of sterols other than cholesterol to overcome the toxicity of thetrans isomer
Authors: Kircher Henry W. , Rosenstein Fumiko U. , Fogleman James C. 
Published: November 2006

AbstractFour species ofDrosophila were tested, for two generations, for viability on media containing 13 different C27, C28 and C29 sterols with and withouttrans‐22‐dehydrocholesterol. Only cholesterol was effective for overcoming the toxic effect of therans derivative for all 4 species. The species varied in their ability to use the 13 sterols for growth, maturation and reproduction for 2 generations. The most tolerant species.D. pseudoobscura, could use 11 of the 13 sterols for structural and hormonal functions, whereas the most sensitive species,D. mettleri, could survive adequately on only 4 and less than adequately on another 3 of the 13 compounds. Desmosterol could not be used by any species, even for 1 generation.
Selective uptake and lack of dealkylation of phytosterols by cactophilic species ofDrosophila
Authors: Kircher Henry W. , Rosenstein Fumiko U. , Fogleman James C. 
Published: November 2006

AbstractThe selective absorption of cholesterol and campesterol and discrimination against sitosterol was demonstrated withDrosophila mojavensis andDrosophila nigrospiracula, using a synthetic medium and 2 natural host cacti. Preferential absorption of trace amounts of phytosterols from a large quantity of other lipids occurred whenD. arizonensis andD. mojavensis were reared from agria cactus. The absence of dealkylation of sitosterol to cholesterol was demonstrated withD. mojavensis andD. mettleri, reared on a sterol‐deficient medium supplemented with sitosterol.
Phospholipid requirement of alkylglycerol monooxygenase from rat liver microsomes
Authors: Ishibashi Teruo , Seyama Kuniaki 
Published: November 2006

AbstractThe alkylglycerol monooxygenase catalyzing the cleavage of the ether bond in alkylglycerol resides in rat liver microsomes. The enzyme preparation was freed of phospholipids by sodium deoxycholate treatment followed by gel filtration in the presence of deoxycholate. The removal of phospholipids markedly decreased the alkylglycerol monooxygenase activity. The activity of the delipidated enzyme, however, could be completely restored by the addition of phospholipid vesicles without detergent. When individual phospholipids were added, anionic phospholipids such as phosphatidylglycerol and diphosphatidyl‐glycerol were the most effective. These findings, along with our previous observation of a similar effect of liposomes on the purified enzyme, indicate that the amphipathic nature of the protein is responsible for the lipid dependence of enzymatic activity.
Effects of dietary triolein and sunflower oil on insulin release and lipid metabolism in zucker rats
Authors: Weekes T. E. C. , Wahle K. W. J. , Lebaijuri M. B. 
Published: November 2006

AbstractObese and lean male Zucker rats were fed ad libitum on diets containing either 50 (L) or 200 (H) g/kg diet of either triolein (T) or sunflowerseed oil (S). The specific activity of the hepatic microsomal Δ9 desaturase enzyme was depressed in both lean and obese rats fed the HS diet compared with the other three diets. The fatty acid composition of liver and subcutaneous white adipose tissue lipids were consistent with a lower Δ9 desaturation activity in rats fed the H diets, particularly for the HS diet. In both genotypes, microsomal Δ9 desaturase activity and the ratio of 16∶1/(16∶0+16∶1) fatty acids in liver lipids were inversely related to the proportion of 18∶2 in liver lipid. Plasma insulin concentrations and rates of glucose‐stimulated insulin release in vivo were higher in obese rats compared with lean rats, and plasma insulin levels were higher in rats fed S compared with T. There was no relationship between Δ9 desaturase activity and either plasma insulin concentration or rates of insulin release in vitro. These findings suggest that hepatic Δ9 desaturase activity of Zucker rats is responsive to changes in the proportion of 18∶2 in liver lipids but is not affected by changes in insulin secretion.
Effect of chlorphentermine on incorporation of [14C]choline in the rat lung phospholipids
Authors: Gonmori Kunio , Morita Tomoaki , Mehendale Harihara M. 
Published: November 2006

AbstractThe effect of chlorphentermine (CP) treatment (50 mg/kg/ day, per os [po]) on the incorporation of [14C]choline into rat lung phospholipid was studied.Total phospholipid content was increased 2.0‐fold and 1.7‐fold after seven and 14 days, respectively, compared with the pair‐fed rats. The incorporation of [14C]choline into phosphatidylcholine (PC) was significantly inhibited by either seven or 14 days of CP treatment. Nevertheless, the PC content was significantly increased by day 7 and stayed elevated at day 14 of CP treatment. Choline and phosphorylcholine contents were significantly decreased by the CP treatment. These results suggest that the higher accumulation of PC is due to inhibition of enzymes involved in the hydrolysis of phospholipids rather than to a stimulation of the phospholipid synthesis.
Determination of the phospholipid composition of trout gill by latroscan TLC/FID: Effect of thermal acclimation
Authors: Hazel Jeffrey R. 
Published: November 2006

AbstractThe phospholipid composition of gill tissue from thermally acclimated rainbow trout,Salmo gairdneri, was determined by Iatroscan analysis following an initial development of the chromarods in a non‐polar solvent to remove neutral lipids. Standard curves for all phospholipids, although linear through most of the concentration range tested (1–40 μg), extrapolated to negative intercepts on the ordinate, indicating a decline in sensitivity at low phospholipid levels. In addition, the concentration dependence of the Iatroscan response varied by nearly 6‐fold among phospholipids. Of the major phospholipids, only lysophosphatidylcholine could not be quantitated accurately because of the presence of an interfering peak. Quantitation by Iatroscan yielded results which, in general, agreed well (within 5%) with results obtained by an independent phosphate analysis. Only in the case of phosphatidylinositol (PI) did the two analytical methods differ significantly; proportions of PI were 55% higher when determined by Iatroscan as opposed to phosphate analysis. Gill tissue from 5 C‐acclimated trout possessed higher proportions of phosphatidylethanolamine than tissue from 20 C‐acclimated trout. The Iatroscan provided a rapid and reliable means of quantitating the proportions of all the major phospholipids of trout gill, although there are some limitations to the general applicability of the technique.
Comparison of the thin layer chromatography/flame ionization detection system with other methods for the quantitative analysis of liver lipid contents in alcohol‐fed rats and controls
Authors: Rao G. Ananda , Riley Diana E. , Larkin Edward C. 
Published: November 2006

AbstractIn this study, we have examined the feasibility of using the Thin Layer Chromatography/Flame Ionization Detection (TLC/FID) system to evaluate the lipid content of alcohol‐induced fatty liver by comparing the results with those from other methods. Various amounts of standards (tripalmitin, phosphatidylcholine and cholesterol) were spotted on Chromarods and scanned either with or without development in a solvent system. The detector responses were significantly greater when the spots were not developed. From the results with developed rods, conversion factors (amount/area) were calculated. These were used for the quantitative analysis of the liver lipids from rats fed a Lieber‐DeCarli ethanol diet or a control diet for four weeks. The triglyceride (TG), phospholipid (PL), cholesterol (CH) and cholesterol ester (CE) contents (65.9, 25.4, 2.9 and 6.8 mg/g, respectively) obtained by the TLC/FID system were similar to those observed by other methods (67.9, 27.6, 3.0 and 8.3 mg/g, respectively). The liver lipid content in control rats also was similar to that obtained by other methods (TG, 19.0 vs 20.6; PL, 24.2 vs 21.8, CH, 2.1 vs 2.1 and CE, 1.8 vs 2.6 mg/g). Thus, the magnitude of changes in liver lipid levels due to chronic alcohol ingestion obtained by alternate methods also was found with TLC/FID. The TLC/FID system provides a convenient method for rapid analysis of the extent of fatty liver in alcohol‐fed animals.
Quantitating heart lipids: Comparison of results obtained using the Iatroscan method with those from phosphorus and gas chromatographic techniques
Authors: Kramer J. K. G. , Farnworth E. R. , Thompson B. K. 
Published: November 2006

AbstractThe precision and accuracy of the Iatroscan method was evaluated by comparing the results obtained with established phosphorus and gas chromatographic techniques. A complete lipid class analysis of rat heart lipids was chosen in order to evaluate the performance of the Iatroscan method for biological samples which contained both neutral lipids and phospholipids. A partial scan and repeat development with chloroform/methanol/water (68.5∶29∶2.5) was introduced to achieve consistently good separations of the phospholipids on the Chromarods in the Iatroscan method. The results showed that the precision of the Iatroscan method for some lipid classes was comparable to that of phosphorus or gas chromatographic techniques, while for other lipid classes it was lower. Compared to the data obtained using the phosphorus method, the Iatroscan data were generally similar, while the gas chromatographic method generally gave lower values. These findings, together with the advantages of time required for analysis, size of sample, and universality of detection, suggest that the Iatroscan is a valuable complementary method for complex lipid analyses.