Vitamin A distribution among fat globule core, fat globule membrane, and serum fraction in milk

In cream suspensions and partly skimmed milks obtained by successive centrifugation from whole milk, the concentration of vitamin A per gram of fat was inversely related to the mean size of fat globules. This result indicated that not all the vitamin A of milk was located in the fat globule core, which was further supported by studies of buttermilk and butter oil fractions obtained by churning of cream. These studies indicated that a portion of the vitamin A was associated with the fat globule membrane. The vitamin A content per gram of fat of purified fat globules was similar to vitamin A content per gram of fat of the whole milk from which they were isolated. This result indicated that the amount of vitamin A in the serum fraction was negligible and that vitamin A was localized in the fat globule and fat globule membrane.     

Distribution of isomeric octadecenoic fatty acids in milk fat

Milk fat octadecenoic acids were isolated by preparative gas-liquid chromatography of their methyl esters and separated into cis and trans isomers by argentation thin-layer chromatography. The distribution of the double bonds in the two fractions was determined by reductive ozonolysis. Cis octadecenoic acids had double bonds in positions 6 to 14. The cis-9 isomer was the most abundant isomer representing approximately 95% of the total. Trans octadecenoic acids had double bonds in positions 6 to 16, the predominant isomer being trans-11 octadecenoic acid. Data illustrating the range of variation in the distribution of positional isomers of octadecenoic acid for herd milk fat and butter are presented. There was no obvious seasonal variation in the distribution pattern. Fat from perirenal and subcutaneous adipose tissue of a dairy cow had composition similar to that of butter samples.     

Redox constituents in milk fat globule membranes and rough endoplasmic reticulum from lactating mammary gland

Milk fat globule membranes (MFGM) and rough endoplasmic reticulum (RER) membranes were isolated from milk and lactating mammary gland from the cow and were characterized by biochemical and electron microscope methods in terms of gross composition (proteins, phospholipids, neutral lipids, cholesterol, RNA, and DNA) and purity. Both fractions contained significant amounts of a b-type cytochrome with several properties similar to those of cytochrome b5 from liver, as well as a rotenone-insensitive NADH- and NADPH-cytochrome c reductase. The b-type cytochrome content in the apical plasma membrane-derived MFGM was of the same order of magnitude as it was in RER membranes. It was characterized by a high resistance to extraction by low- and high-salt concentrations and nonionic detergents. MFGM contained much more flavin and much higher activities of xanthine oxidase than the RER membranes. The same redox components were found in MFGM and mammary RER from women, rats, mice, and goats, but in absolute contents great differences between the species were noted. The cytochromes described here differed from liver cytochrome b5 in some spectral properties. The alpha-band of the reduced hepatic cytochrome b5 is asymmetric with a maximum at 555 nm that is split into two distinct peaks at low temperatures. The alpha-band of the b-type cytochromes from MFGM and mammary RER appears as one symmetrical peak at about 560 nm that is not split at low temperatures. When treated with cyanide, MFGM and mammary microsomes showed difference spectra of a reduced b-type cytochrome. Under the same conditions, liver microsomes gave a completely different spectrum. These findings demonstrate the presence of a b-type cytochrome and associated redox enzymes in MFGM, i.e., a derivative of the apical cell surface membrane that is regularly used for envelopment of the milk fat globule during secretion.     

Milk fat globule glycoproteins in human milk and in gastric aspirates of mother''s milk-fed preterm infants

The change of brain lesion load, measured on T2-weighted magnetic resonance imaging (MRI) using computer-assisted techniques, is a widely used secondary endpoint for phase III clinical trials in multiple sclerosis (MS). Collection, transfer, and analysis of the electronic data across multiple centers have all proved challenging and give rise to potential errors. However, many new acquisition schemes and postprocessing techniques have been developed; these may reduce scan times and result in better lesion conspicuity or lessen the human interaction needed for data analysis. This review considers many aspects of the use of MRI in clinical trials for MS and provides international consensus guidelines, derived from a task force of the European Magnetic Resonance Networks in Multiple Sclerosis (MAGNIMS) together with a group of North American experts. The main points considered are the organization of correctly powered trials and selection of participating sites; the appropriate choice of pulse sequences and image acquisition protocol given the current state of technology; quality assurance for data acquisition and analysis; accuracy and reproducibility of lesion load assessments; and the potential for the application of quantitative methods to other MRI-derived measures of disease burden.     

Dietary fat, trans fatty acids, and risk of coronary heart disease

Results from human feeding studies and recent large-scale epidemiologic surveys suggest that dietary trans fatty acids enhance the risk of developing coronary heart diseases. Despite a lack of accurate data regarding dietary intake of trans fatty acids, existing epidemiologic data and evidence from experimental feeding studies support the idea that lowering current intakes of trans fatty acids may lower the risk of coronary heart disease.     

Red cell membrane fatty acids, cytosolic phospholipase-A2 and schizophrenia

Forty subjects with schizophrenia and 40 age- and sex-matched controls were recruited, and blood samples were obtained for analysis of red cell membrane fatty acid composition by capillary gas chromatography. A blood sample was also taken from the same population to test for allelic association between schizophrenia and a polymorphism close to the promoter site of the cytosolic phospholipase-A2 gene which is mapped to chromosome 1q25. The schizophrenic population was heterogeneous with regards age, symptoms severity and treatment. A significantly higher percentage concentration of dihomogamma-linolenic acid (DGLA) was found in the red cell membranes of schizophrenics compared to matched controls. All other fatty acids examined showed no difference from the normal population. No correlation was found between any demographic factor, treatment variable, diet, drug use, alcohol or tobacco consumption which could explain the biochemical findings. A negative correlation was found between the concentration of DGLA in red blood cell (RBC) membranes and severity of symptoms of schizophrenia. In particular, there was a significant correlation (r = -0.41, p = 0.009) between DGLA percentage concentrations and 'disorganised' symptoms. No association was found between schizophrenia and alleles of the polymorphism near the phospholipase-A2 gene or between fatty acid concentrations and the presence of any particular alleles. This study therefore finds support for membrane phospholipid abnormalities in patients with schizophrenia and particular symptom clusters, but does not replicate a previous report of an allelic association between a polymorphism close to the site of the cytosolic phospholipase-A2 gene and schizophrenia.     

Purification and characterization of novel whey glycoprotein WGP-88 which binds to a monoclonal antibody to PAS-4 glycoprotein in the bovine milk fat globule membrane

A monoclonal antibody to the PAS-4 glycoprotein (78 kDa) of the bovine milk fat globule membrane (MFGM) specifically recognized PAS-4, and was named KAS4. A component recognized by KAS4 was found in whey protein, this being a glycoprotein of 88 kDa by SDS-PAGE and named WGP-88. WGP-88 was purified and characterized in comparison with PAS-4. WGP-88 had apparent pI values of 6.45 and 6.39, while those of PAS-4 were 7.39 and 7.35. Neuraminidase digestion shifted the pI values of WGP-88 to 6.57 and of PAS-4 to 7.52. WGP-88 was rich in polar amino residues (44.9 mol%), while PAS-4 was abundant in nonpolar amino acid residues (48.7 mol%). WGP-88 contained 17.1% of carbohydrate and PAS-4 had 7.2%. The results of reductive hydrolysis, N-glycanase digestion, and a lectin blot analysis suggested that N- and O-linked sugar chains were contained in both glycoproteins. WGP-88 and PAS-4 had a different N-terminal amino acid sequence. WGP-88 and PAS-4 respectively inhibited competitively the binding of KAS4 to PAS-4 and WGP-88. Our studies revealed WGP-88 recognized by KAS4 mAb to be a novel whey protein and to have different biochemical properties from those of PAS-4.     

Fatty acid profile and physical properties of milk fat from cows fed calcium salts of fatty acids with varying unsaturation

Holstein cows (n = 24) averaging 42 d in milk were used in a randomized complete block design during a 4-wk trial. A control total mixed ration (TMR) was compared with TMR supplemented with Ca salts of fatty acids from canola oil, soybean oil, or linseed oil. The three vegetable oils were progressively more unsaturated; the dominant fatty acids were, respectively, cis-delta-9-C18:1, C18:2, and C18:3. Apparent total tract digestibility of dry matter, crude protein, ether extract, and neutral detergent fiber was higher for rations containing Ca salts than for the control ration. Milk yield increased linearly as the unsaturation of the dominant fatty acid in the Ca salts increased. Milk fat percentage was reduced when Ca salts were added to the rations. The addition of Ca salts to the ration decreased the proportions of saturated fatty acids that contained C6 to C16 and increased the proportions of C18:0, cis-delta-C18:1, and trans-delta-11-C18:1 in milk fat. Proportions of C18:2 and C18:3 increased linearly, and cis-delta-9-C18:1 decreased linearly, as the unsaturation of the dominant fatty acid in the Ca salts increased. The proportion of fat that was liquid at 5 degrees C was higher for butter from cows fed diets containing Ca salts, but the proportion of liquid fat at 20 degrees C was not affected. Calcium salts of unsaturated fatty acids added to the diets of dairy cows improved the thermal properties of milk fat.     

Ursodeoxycholic acid improves the hepatic metabolism of essential fatty acids and retinol in children with cystic fibrosis

An ELISA sandwich for the detection of Giardia lamblia antigens in human faeces was standardized. 175 samples were studied: 77 positive, 61 negative to cysts and/or trophozoites by direct faeces test, and 19 positive to other parasite different from G. lamblia. The sensitivity of the technique was 94.8% and the specificity 98.3%. The method detects an antigen concentration of 31 ng. The procedure is simple, sensitive and specific so, it may be useful for diagnosis and in epidemiological studies.     

Selective extraction of alkaline phosphatase and 5'-nucleotidase from milk fat globule membranes by a single phase n-butanol procedure

A single phase extraction procedure employing 8% (v/v) n-butanol at room temperature extracted over 90% of alkaline phosphatase activity and over 60% of 5'-nucleotidase activity from bovine milk fat globule membranes (MFGM). For 5'-nucleotidase, higher n-butanol concentrations lead to loss of activity, while lower concentrations were ineffective in extracting the enzyme. When extractions were performed at 0 degrees C, similar yields were obtained for alkaline phosphatase extraction with 8% (v/v) n-butanol, but 5'-nucleotidase extraction required 10% (v/v) n-butanol for similar yields. However, 5'-nucleotidase was less susceptible to denaturation during extraction at 0 degrees C. The Km values and substrate specificities for both alkaline phosphatase and 5'-nucleotidase were unchanged by extraction with 8% (v/v) n-butanol. The 8% (v/v) n-butanol extraction procedure provides a 3-fold purification step, and an enzyme preparation suitable for further purification.     

Plasma and erythrocyte alpha-tocopherol and plasma retinol concentrations in term infants fed formula enriched with long-chain polyunsaturated fatty acids

OBJECTIVE: To assess the effect of long-chain polyunsaturated fatty acids (LCPUFA)- and vitamin E-supplemented formula feeding on erythrocyte and plasma alpha-tocopherol (VE), and plasma retinol (VA) concentrations in neonates and to compare these values with those found in infants feeding on infant formula without LCPUFA or breast milk SETTING: University Hospital of Granada, Spain. SUBJECTS: 49 full-term infants. DESIGN AND INTERVENTION: Subjects who chose not to breast feed were fed either (i) unsupplemented infant formula (F) or (ii) infant formula supplemented with LCPUFA and vitamin E (FL). Alpha-tocopherol and retinol were measured at 7 days, 1 month and 3 months. RESULTS: Plasma and erythrocyte VE concentrations and plasma VE/total lipids ratio increased significantly in all groups at 1 month of life (P < 0.05), but did not change significantly between 1 month and 3 months in any group (P > 0.05). Erythrocyte VE and VA retinol concentrations were higher in infants fed an infant formula than in breast milk-fed infants at 1 month of life (P < 0.05). Finally, there were no significant differences in plasma or erythrocyte VE levels, plasma VA or plasma VE/total lipid ratio between any groups at 3 months of life (P > 0.05). CONCLUSION: Infants fed on LCPUFA- and vitamin E-supplemented infant formula for 3 months have similar vitamin E and A status to infants fed on breast milk or infant formula without LCPUFA supplementation.     

Effect of dietary forage concentration and buffer addition on duodenal flow of trans-C18:1 fatty acids and milk fat production in dairy cows

The objective of the study was to determine the effects of dietary fat source on duodenal flow, apparent absorption, and milk fat incorporation of trans-C18:1 fatty acids. Four ruminally and duodenally cannulated multiparous Holsteins cows in mid to late lactation were fed a basal diet containing 36% corn silage, 24% alfalfa haylage, and 40% concentrate (dry matter basis). Diets contained 0% supplemental fat (control diet), 3.7% high oleic sunflower oil, 3.7% high linoleic sunflower oil, or 3.7% partially hydrogenated vegetable shortening; treatments were administered in a 4 x 4 Latin square design with 3-wk experimental periods. The flow of trans-C18:1 to the duodenum was higher for cows fed diets supplemented with fat than for cows fed the control diet (283 vs. 64 g/d). Incomplete biohydrogenation accounted for the increased flow of trans-C18:1 to the duodenum in cows fed diets containing high oleic and high linoleic sunflower oil. Increased flow of trans-C18:1 in cows fed the diet containing partially hydrogenated vegetable shortening most likely originated from the trans-C18:1 in the diet. Milk fat percentages were 3.48, 3.07, 3.18, and 3.38% for cows fed the control diet and diets containing high oleic sunflower oil, high linoleic sunflower oil, and vegetable shortening, respectively. Milk trans-C18:1 increased from 2.9 to 11.2% of the total fatty acids for cows fed the control diet and the diets supplemented with fat, respectively. Milk trans-C18:1 were equal across all diets supplemented with fat. Ruminal and total tract digestion of organic matter, neutral detergent fiber, and N did not change with fat supplementation. Results showed that trans-C18:1 is increased in the milk of cows with reduced milk fat; however, excessive amounts of trans-C18:1 in milk do not necessarily correspond directly to milk fat depression.     

Plasma and tissue levels of lipids, fatty acids and plasma carnitine in neonates receiving a new fat emulsion

This study was undertaken to compare Intralipid with a new fat emulsion containing gamma-linolenic acid and carnitine, named Pediatric Fat Emulsion 4501, in neonates with regard to lipid and carnitine metabolism over a short period of total parenteral nutrition. There were 10 neonates in each group and they tolerated the total parenteral nutrition well. In spite of the gamma-linolenic acid supplementation in the new emulsion, arachidonic acid decreased significantly in plasma lipid esters and adipose tissue in both groups after 5 d of treatment. Also, there was a decrease in plasma docosahexaenoic acid which was more pronounced in the treatment group. The relative percentage values of linoleic and linolenic acids in adipose tissue were increased, indicating that newborns have a rapid accretion of fatty acids. Plasma-triglycerides were effectively cleared during the periods without fat infusion. In the group that received Pediatric Fat Emulsion 4501 the means of both free and total plasma carnitine concentrations increased significantly, whereas they tended to decrease in the Intralipid group.     

Stability of n-3 fatty acids in human fat tissue aspirates during storage

Six cases of atypical and malignant meningioma studied by intraoperative crush preparations are reported. Four atypical meningiomas were characterized by large cohesive and dyshesive cell clusters showing slightly pleomorphic nuclei and scant cytoplasm. The papillary meningioma yielded dyshesive groups of pleomorphic cells with variable and well-defined cytoplasm. The malignant meningioma, hemangiopericytic type, showed dyshesive cells with scant, ill-defined cytoplasm and spindle-shaped or vesicular nuclei.     

Decreased membrane fluidity and unsaturated fatty acids in Niemann-Pick disease type C fibroblasts

We have investigated transformation with heterologous DNA as a method for insertional mutagenesis of Aspergillus fumigatus. Two methods, polyethylene glycol-mediated transformation of protoplasts and electroporation of germinating spores, were used to establish conditions leading to single-copy integration of transforming DNA at different genomic sites. We have assessed the effect of restriction enzyme-mediated integration (REMI) for both methods. Non-REMI protoplast transformation led to integration of multiple copies of transforming DNA in the majority of transformants. Results of REMI with protoplast transformation varied depending on the enzyme used. Low concentrations of several restriction enzymes stimulated transformation, but of ten enzymes investigated only REMI with XhoI and KpnI resulted in single-copy integration of transforming DNA for the majority of transformants. For protoplast transformation with XhoI- or KpnI-based REMI, 50% and 76% of insertions, respectively, were due to integrations at a genomic enzyme site corresponding to the enzyme used for REMI. Electroporation of spores without addition of restriction enzyme resulted in a high transformation efficiency, with up to 67% of transformants containing a single copy of transforming DNA. In contrast to protoplast transformation, electroporation of spores in the presence of a restriction enzyme did not improve transformation efficiency or lead to insertion at genomic restriction sites. Southern analysis indicated that for both protoplast transformation with REMI using KpnI or XhoI and for electroporation of spores without addition of restriction enzymes, transforming DNA inserted at different genomic sites in a high proportion of transformants.     

Effect of infused volatile fatty acids and caseinate on milk composition and coagulation in dairy cows

Milk protein secretion is changed by increasing the proportion of energy, mainly as propionic acid, or the availability of AA. Whether associative effects exist between energy nature and protein amounts is unknown. Therefore, ruminal isoenergetic infusions of low or high propionate mixtures were combined factorially with duodenal infusion of sodium caseinate or control. Four ruminally and duodenally fistulated Holstein cows were used. The diet was limited and consisted of 70% forage and 30% concentrate. Caseinate infusion increased milk yield and protein and casein contents and decreased milk fat content; curd yields and coagulation properties of milk were improved. The infusion of propionic acid caused a large increase in rumen propionate. Milk yield tended to decrease, and milk fat decreased, but protein, casein, and curd yields were unchanged; milk-coagulating properties were improved. No interaction existed between energy and protein amounts. Alteration of VFA had little effect on milk composition, but increasing the protein supply to the duodenum increased milk protein.     

The effect of dietary oil containing (n-3) fatty acids on the fatty acid, physicochemical, and organoleptic characteristics of pig meat and fat

An investigation was made to alter the fatty acid composition of pork and a pork product in line with human dietary advice while not adversely affecting factors controlling consumer acceptability. Pigs (n = 150) were assigned to three dietary treatments with 25 intact male-female pairs per treatment. Diet A (control) contained 3% of a 4:1 (wt/ wt) tallow-soybean oil mixture. Diets B and C contained 2% rapeseed oil plus 1% fish oil. Diets A, B, and C were supplemented with 100, 100, and 250 mg of all-rac-alpha-tocopheryl acetate/kg of diet, respectively. Pigs were given ad libitum access to feed from 52 kg live weight until 95 kg (slaughter). Sausages were prepared from the resulting cuts. Tissues of pigs were evaluated in terms of fat firmness, color, fatty acid composition, and contents of alpha-tocopherol and thiobarbituric acid-reactive substances (TBARS). Organoleptic characteristics of chops and sausages were evaluated by a trained taste panel. Pigs fed Diets B and C had improved feed conversion ratios (P < .05) and ADG compared with control pigs. The levels of n-3 (omega-3) polyunsaturates were significantly increased in the tissues and sausage from pigs fed Diets B and C with associated alterations in n-6 to n-3 fatty acid ratios that accorded with contemporary human dietary recommendations. Levels of alpha-tocopherol and TBARS were significantly altered in the tissues. There were no appreciable differences between treatments in carcass characteristics, including color. The overall organoleptic acceptability of chops and sausages was not different between the treatments.     

Profiles of the fatty acids in the plasma membrane of human brain tumors

The ionic channels and signal transduction pathways underlying the 5-hydroxytryptamine (5-HT)-induced hyperpolarization in neurons of the rat dorsolateral septal nucleus (DLSN) were examined by using intracellular and voltage-clamp recording techniques. Application of 5-HT (1-50 microM) caused a hyperpolarizing response associated with a decreased membrane resistance in DLSN neurons. The hyperpolarization induced by 5-HT was blocked by Ba2+ (1 mM) but not by tetraethylammonium (TEA, 3 mM), glibenclamide (100 microM) and extracellular Cs+ (2 mM). 8-Hydroxy-di-n-propylamino tetralin (8-OH-DPAT; 3 microM), a selective agonist for the 5-HT1A receptor, mimicked 5-HT in producing the hyperpolarization. The 5-HT hyperpolarization was blocked by NAN-190 (5 microM), a 5-HT1A receptor antagonist. CP93129 (100 microM), a 5-HT1B receptor agonist, and L-694-247 (100 microM), a 5-HT1B/1D receptor agonist, also produced hyperpolarizing responses. The order of agonist potency was 8-OH-DPAT > CP93129 > or = L-694-247. (+/-)-2,5-Dimethoxy-4-iodoamphetamine hydrochloride (DOI, 100 microM), a 5-HT2 receptor agonist, and RS67333 (100 microM), a 5-HT4 receptor agonist, caused no hyperpolarizing response. The voltage-clamp study showed that 5-HT caused an outward current (I5-HT) in a concentration-dependent manner. I5-HT was associated with an increased membrane conductance. I5-HT reversed the polarity at the equilibrium potential for K+ calculated by the Nernst equation. I5-HT showed inward rectification at membrane potentials more negative than-70 mV. Ba2+ (100 microM) blocked the inward rectifier K+ current induced by 5-HT. I5-HT was irreversibly depressed by intracellular application of guanosine 5'-O-(3-thiotriphosphate)(GTP-gamma S) but not by guanosine 5'-O-(2-thiodiphosphate) (GDP beta S). These results suggest that in rat DLSN neurons activation of 5-HT1A receptors causes a hyperpolarizing response by activating mainly the inward rectifier K+ channels through a GTP-binding protein.     

Orange fruit is more effective than are dark-green, leafy vegetables in increasing serum concentrations of retinol and beta-carotene in schoolchildren in Indonesia

The objectives of this study were to quantify the effectiveness of dietary retinol sources, orange fruit, and dark-green, leafy vegetables in improving vitamin A status, and to test whether orange fruit is a better source of vitamin A and carotenoids than are leafy vegetables. Anemic schoolchildren aged 7-11 y (n = 238) in West Java, Indonesia, were randomly allocated to 1 of 4 groups to consume 2 complete meals/d, 6 d/wk, for 9 wk: 1) 556 retinol equivalents (RE)/d from retinol-rich food (n = 48); 2) 509 RE/d from fruit (n = 49); 3) 684 RE/d from dark-green, leafy vegetables and carrots (n = 45); and 4) 44 RE/d from low-retinol, low-carotene food (n = 46). Mean changes in serum retinol concentrations of the retinol-rich, fruit, vegetable, and low-retinol, low-carotene groups were 0.23 (95% CI: 0.18, 0.28), 0.12 (0.06, 0.18), 0.07 (0.03,0.11), and 0.00 (-0.06, 0.05) micromol/L, respectively. Mean changes in serum beta-carotene concentrations in the vegetable and fruit groups were 0.14 (0.12, 0.17) and 0.52 (0.43, 0.60) micromol/L, respectively. Until now, it has been assumed that 6 microg dietary beta-carotene is equivalent to 1 RE. On the basis of this study, however, the equivalent of 1 RE would be 12 microg beta-carotene (95% CI: 6 microg, 29 microg) for fruit and 26 microg beta-carotene (95% CI: 13 microg, 76 microg) for leafy vegetables and carrots. Thus, the apparent mean vitamin A activity of carotenoids in fruit and in leafy vegetables and carrots was 50% (95% CI: 21%, 100%) and 23% (95% CI: 8%, 46%) of that assumed, respectively. This has important implications for choosing strategies for controlling vitamin A deficiency. Research should be directed toward ways of improving bioavailability and bioconversion of dietary carotenoids, focusing on factors such as intestinal parasites, absorption inhibitors, and food matrixes.