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Results for “Lipid modification”

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At least 703 records · Page 39Linked to original sources
PubMed1991

Dietary modification of yolk lipid with menhaden oil.

Due to the numerous proposed cardiovascular benefits associated with consumption of omega-3 fatty acids, marketing of an egg enriched by omega-3 fatty acid may benefit the egg producer. Effects on yolk composition of a standard laying hen diet enriched with 3% menhaden oil (test diet), versus an isocaloric (control) diet containing no added fat, were evaluated for 18 wk. Dietary menhaden oil did not alter egg production, egg weight, total yolk fat, or yolk cholesterol. However, yolk contents of omega-6 and omega-3 fatty acids were influenced by diet. Arachidonic acid decreased and eicosapentaenoic acid increased in eggs from hens fed the test diet following 1 wk of dietary treatment. Docosahexaenoic acid and linolenate increased in eggs from hens fed the test diet at 2 and 3 wk of the trial, respectively. These alterations in yolk composition resulted in a decrease in the ratio of omega-6 to omega-3 fatty acids from 18 for eggs from hens fed the control diet to 3 for eggs from hens fed the test diet. At Weeks 14 and 18, hens (n = 10 per diet) were killed and necropsied. No change in gross scoring of hepatic lipidosis was observed. Histologically, significantly greater scores for hepatocellular lipid infiltration were recorded for liver sections from hens fed menhaden oil than for control hens. Increased microscopic hepatic lipid infiltration observed with dietary omega-3 administration may have significance for flocks predisposed to fatty liver syndrome and may also provide a unique system in which to study the effects of dietary omega-3 fatty acids on liver lipid metabolism.

Animals↗
PubMed1992

[Modification of Memebrane Lipid composition by lipophilic agents, and its effect on the activity of membrane-bound enzymes].

Rat jejunum was perfused for two and a half hours with aqueous ethanol (volume fraction 0.05) or aqueous carbon tetrachloride (volume fraction 0.005). Membrane vesicles subsequently prepared from the brush border displayed markedly decreased contents of cholesterol and phospholipids, as well as decreases in the activities of membrane-bound enzymes. These decreases were more pronounced in vesicles prepared after carbon tetrachloride than after ethanol perfusion. It is suggested that the anchoring of membrane-bound enzymes is decreased by physical chemical alterations in the hydrophobic region of the membrane.

Animals↗
PubMed1992

[Diet and hypertriglyceridemia: influence of dietary modifications on plasma lipids, lipoproteins and apoproteins in patients with primary hypertriglyceridemia].

BACKGROUND: To investigate the influence of dietary changes on plasma lipoproteins and apoproteins in 10 patients with hypertriglyceridemia (plasma triglycerides greater than 1000 mg/dl). METHODS: A sequential study with three periods was designed: 1) Inclusion with uncontrolled free diet; 2) Two weeks of a diet with about 1000 calories/day, controlled with a daily survey; and 3) One week of "free" diet of about 2000 calories. At the end of the three periods the following were measured in each patient: weight, glycemia, plasma IRI and C-peptide, plasma, triglycerides, cholesterol, chylomicron, VLDL, LDL and HDL cholesterol. At the end of the second and third periods the caloric and immediate principles intake were individually considered. RESULTS: A reduction in plasma cholesterol and triglycerides was observed in all cases after the caloric reduction, and also a disappearance of chylomicrons. The reduction of triglycerides took place in all lipoproteins. By contrast, after the low-calorie diet only the VLDL-cholesterol was reduced, while LDL- and HDL-cholesterol increased. The apo C-III/apo C-II ratio was significantly reduced after the low-calorie diet. The plasma glycemia, IRI and C-peptide were negatively correlated with LDL-cholesterol and with the apo C-III/apo C-II ratio. The best model to explain the oscillations of plasma triglycerides depending on the diet was that including the three ingested immediate principles together with the total diet calories. CONCLUSIONS: During the caloric restriction there would be an increased catabolism of VLDL to LDL. This reduction would be mediated by C-III and C-II apoproteins, probably through the oscillations of plasma IRI.

Apolipoproteins↗
PubMed2006

Chemical stability of lipid excipients in SLN-production of test formulations, characterisation and short-term stability.

The study investigates the chemical stability of lipids used as excipients in the production of solid lipid nanoparticles (SLN). A total of 17 SLN formulations was produced using different lipids. Most of the formulations were produced using identical binary surfactant mixtures and concentrations to study the effect of the chemical nature of the lipid on its stability in SLN. In some formulations surfactants were exchanged to study the contribution of the surfactant. The particles were characterised by photon correlation spectroscopy, laser diffractometry, zeta potential determination and differential scanning calorimetry, the latter to assess potential effects of lipid crystallinity and modifications on lipid stability. Lipid analysis was performed by gas chromatography using a sampling preparation and analysis procedure especially developed for SLN. This short-term study provides primarily information about the stability of the lipid under production conditions, that means high pressure homogenisation (cavitation) at high temperature. No degradation products couldbe detected for all lipids, the production process itself did not impair excipient stability.

Calorimetry, Differential Scanning↗
PubMed1991

Isocaloric modification of dietary lipids influences intestinal brush border membrane composition in diabetic rats.

Variations in the dietary fatty acid composition and cholesterol content are associated with alterations in the intestinal uptake of hexoses and lipids in control and diabetic rats. Changes in the composition of the brush membrane (BBM) lipids may provide a possible mechanism for the observed alterations in transport properties. Accordingly, control and streptozotocin diabetic animals were fed one of four isocaloric semisynthetic diets for two weeks: beef tallow with low cholesterol, beef tallow with high cholesterol, fish oil with low cholesterol or fish oil with high cholesterol. BBM were prepared and assessed for marker enzyme activity and lipid composition. Fish oil feeding was associated with a reduction in total phospholipid content in control and diabetic jejunal and ileal BBM; this fall in total phospholipids was due to a reduction in BBM sphingomyelin. Cholesterol supplementation increased control jejunal BBM sucrase activity in animals fed beef tallow but reduced sucrase activity in animals fed fish oil. In fish oil fed diabetic animals, jejunal and ileal BBM alkaline phosphatase activity was increased with cholesterol supplementation. The elevation in BBM total phospholipids (phosphatidylethanolamine) associated with diabetes in beef tallow fed animals was not observed in the jejunal BBM of animals fed fish oil or in the ileal BBM of animals fed fish oil with high cholesterol. Thus, (a) feeding an omega-3 polyunsaturated fatty acid diet (fish oil) reduced total phospholipid content in BBM of control and diabetic animals, primarily due to a reduction in sphingomyelin; and (b) feeding an omega-3 polyunsaturated fatty acid diet or dietary cholesterol supplementation alter the activity of BBM enzymes. These results suggest that variations in dietary fat composition and the associated changes in BBM composition and enzyme activity contribute to altered intestinal function in diabetes.

Animals↗
PubMed1988

[Modification of serum lipids and glucose tolerance by sequential Ovosiston and Minisiston].

The influence of two kinds of contraceptive pills, a sequential one and a combined one (Sequenz-Ovosiston and Minisiston), on serum lipoproteins and carbohydrate metabolism was investigated in 32 young patients who got these drugs for the first time during a period of 12 months. There were no pathological values of cholesterol, high density proteins, low density proteins, triglycerides or oral glucose tolerance test during and after the treatment. The authors summarized, that neither Sequenz-Ovosiston nor Minisiston increase the risk of atherosclerosis and of diabetes in young healthy women.

Adolescent↗
PubMed1988

[Dietary modification of bile lipids].

The average incidence of gallstones in european countries is about 25%. Excessive secretion of cholesterol into the bile can predispose to saturation and gallstone-formation. Obesity, overnutrition, diets rich in refined carbohydrates, diets high in cholesterol intake and poor in dietary fibre, lipid lowering drugs, age and female sex hormones are recognized causing increased cholesterol secretion into the bile. These metabolic consequences may predispose to a higher incidence of cholesterol gallstone than in normal persons. Taking all the results of the literature together patients with gallstones should be encouraged to take a low cholesterol, low calorie, low refined carbohydrate and high polyunsaturated fat diet rich in bran und vegetable fibre. Obese patients should reduce their body weight. These dietary recommendations should be given for patients with gallstones during bile acid therapy and after successful dissolution in order to prevent gallstone recurrence.

Bile↗
PubMed1986

The short-term effects of an intervention programme on the modifications of plasma lipids in workers. The pilot study.

The purpose of the pilot study was to determine the effectiveness of a medical intervention program in the reduction of plasma lipids in a group of hyperlipemic persons. Two groups were compared in this study over a one year period. The groups consisted of a group of hyperlipemic persons with TG levels greater than 150 mg% and a second group with plasma lipids within normal limits. The plasma lipids concerned in this study were cholesterol, triglycerides, and HDL-C. The group of hyperlipemic subjects received intense nutritional counselling while the normal subjects received only printed guidelines to normal healthy nutrition. The results of this study, confirm positive results obtained by other intervention programs. A substantial reduction in TG levels was observed in 37.7% of the hyperlipemic group while 14.1% of the normal group had considerable increases in their TG levels during this one year study period. The results of the serum lipid surveys proved the high interyear correlation for both HDL-C and TC, but a very much weak interyear correlation for TG.

Body Weight↗