Serum Total Fatty Acids Research Articles

Microdetermination of lipids and serum total fatty acids

Colorimetric methods for the estimation of lipids, covering a range of 2 μg to 1.33 mg are described. The principle involved is the oxidation of lipids in acid-dichromate. Using iodometric colorimetry for the determination of microgram amounts of lipid, a procedure for the determination of serum total fatty acids requiring only 15 μl of serum is described.

Serum Lipids and Diet: A Comparison between Three Population Groups with Low, Medium and High Fat Intake

Serum cholesterol, serum total and polyunsaturated fatty acids and diet of three populations were compared. Of two groups of African negoes examined, one took 6.8 and the other 37.8% of its calories as lipids, almost exclusively of vegetable origin. The third group (negroes from Nashville) consumed 48.3% of its dietary calories as fats, mainly of animal origin. Their dietary linoleic acid represented, respectively, less than 1, 2 and 6% of their total caloric intake. The Nashville group had the highest serum cholesterol level, but there was little difference in the serum cholesterol of the other two groups. Serum total fatty acids of the three groups were not very different. From the observations of total and individual polyenoic fatty acids in these groups, it appears that there is a threshold value of dietary linoleic acid governing the pattern of serum fatty acids: below this threshold, serum total polyunsaturated fatty acids are low owing to a decline in dienoic and tetraenoic acids, despite relatively high trienoic, pentaenoic and hexaenoic acid levels. Above this threshold value, the opposite phenomenon was observed. In this range, a change from 2 to 6% dietary linoleic acid did not alter the serum polyenoic fatty acid levels appreciably, except perhaps for the trienoic acid.

Control of serum lipids by diet and triparanol (MER 29)

The effect of a low animal fat diet and of Triparanol (MER 29) was studied in ten cases of cardiovascular disease and in four cases of xanthomatosis with hypercholesterolaemia who had no known vascular involvement. With this treatment, cholesterol levels were effectively reduced in 57 % of cases. Triparanol given alone was effective in 36 %, and dietary control alone in 38 %. Serum phospholipids were apparently not affected by Triparanol, but in 33 % of cases they were reduced by dietary control alone. The response of serum total fatty acids was inconclusive. Attention is drawn to the difficulties in interpreting these results, and particularly to the tendency in a significantly high proportion of cases for the base-line levels of serum cholesterol to fluctuate widely. This method of control of serum lipids is apparently not effective unless the serum cholesterol is greater than 300 mg/100 ml, in which case dietary control should be applied first, supplemented later by Triparanol if necessary, and if effective. L'effet d'un régime pauvre en graisses animales et du Triparanol (M.E.R. 29) fut étudié dans 10 maladies cardiovasculaires et dans 4 xanthomatoses avec hypercholestérolémie qui n'avaient pas de lésion vasculaire connue. Avec ce traitement le taux du cholestérol fut effectivement diminué dans 57 des cas. Le Triparanol seul fut actif dans 36 % et le régime seul dans 38 %. Les phospholipides sériques ne furent pas modifiés par le Triparanol mais ils furent diminués dans 33 % des cas par le régime seul. Les modifications des acides gras totaux du sérum ne furent pas significatives. L'accent est mis sur les difficultés d'interprétation de ces résultats et spécialement sur les fluctuations spontanées de la cholestérolémie de base trouvées dans une proportion élevée des cas. Cette méthode de contrôle des lipides sériques ne semble efficace que si le cholestérol sérique dépasse 300 mg/100 ml. Le traitement diététique doit être essayé d'abord puis si nécessaire complété par le Triparanol. Bei 10 Fällen von cardiovasculären Erkrankungen sowie bei 4 Fällen von Xanthomatosis mit Hypercholesterinaemie ohne nachweisbare cardiovasculäre Beteiligung wurde der Einfluss von an tierischen Fetten armer Diät and von Triparanol (M.E.R. 29) untersucht. Durch these Behandlung wurde in 57 % der Fälle der Cholesterinspiegel deutlich herabgesetzt. Triparanol alleine war in 36 % and Diät alleine in 38 % der Fälle erfolgreich. Die Phospholipide wurden durch Triparanol nicht beeinflusst, in 33 der Fälle wurden she aber durch Diät alleine herabgesetzt. Die Reaktion der Gesamtfettsäuren im Serum war nicht eindeutig. Es wird auf die Schwierigkeit der Interpretation dieser Ergebnisse aufmerksam gemacht and besonders darauf, dass in einem signifikant hohen Prozentsatz der Fälle die Tendenz zu grossen Schwankungen der Basis-Serumcholesterinwerte besteht. Diese Methode zur Regulierung der Serumlipide ist offenbar ohne Erfolg, wenn der Serumcholesterinspiegel 300 mg % nicht übersteigt. Ist dies der Fall, so sollte zunächst Diät verordnet werden, die notwendigenfalls später durch Triparanol ergänzt wird.

Effects of caloric intake on clearance of injected lipids in rabbits and rats.

Rabbits fasted 3 and 10 days displayed marked increases in serum total fatty acids and total cholesterol, limited increases in lipid phosphorus and a distinct inability to clear intravenously injected triglycerides from the serum. Limited feeding in which rabbits were losing weight over a 10-day period resulted in essentially no change, either in serum lipid components or lipid removal rates. The adverse effects of fasting on serum lipid clearance appeared to be partially overcome by injecting additional glucose at the time of lipid administration, and completely overcome by giving heparin intravenously 15 minutes prior to lipid injection. Rats fasted 4 days showed decreased levels of serum total fatty acids, lipid phosphorus and total cholesterol, but maintained normal rates of serum lipid clearance. Limited-fed rats showed less pronounced decreases in serum total fatty acids, lipid phosphorus and total cholesterol, and also maintained normal serum lipid clearance.

Studies on Arteriosclerosis (I) : Serum Lipid Level of Normal Subjects and then of Subjects with Coronary Diseases, Diabetes, Cerebral Apoplexy and Hypertension

Various investigations have been per- formed about the pathogenesis of atherosclerosis, and the view has recently become dominant that the disease is caused by disturbance of lipid metabolism. The author studied the serum lipid values of normal subjects of various ages and then of subjects with coronary diseases, diabetes, cerebrovascular diseases and hypertension. Each of the individuals was tested, as far as possible for all the items, cholesterol, lipoprotein index, free fatty acid, total fatty acid, neutral fat and phospholipid, and an attempt was made to determine which of them might serve as the best pointers of atherosclerosis. Experimental Methods The subjects consisted of 106 normotensive persons those whose blood pressure was consistently below 140/90 mmHg by repeated measurement--32 cases of diabetes mellitus. 22 of angina pectoris, 30 of myocardial infarction, 30 of cerebrovascular lesions and 101 of hypertension. The measurement of serum lipid fractions was carried out by the methods show below. 1) Cholesterol : Costello's method. 2) Lipoprotein index : paper electrophoresis. 3) Total fatty acid : extraction by Bloor and Katsura-Hatakeyama's method and measurement by alkali titration. S) Neutral fat : extraction by the same method and measurement by Bragdon's method. 6) Phospholipid : modified Zilversmit's method. Results 1) Serum lipid levels of normotensive subjects. In normotensive subjects under 50 years, the serum total cholesterol level was 167±35 mg/dl, free cholesterol level 52±15 mg/dl, average lipoprotein index 2.9±1.2, nonesterified fatty acid 0.25±0.12 mEq/l, serum total fatty acid level 268± mEq/l, serum neutral fat level 187±50 mg/dl, serum phospholipid level 155±36 mg/dl, and serum CIP ratio 0.97±0.26 ; and those levels above 50 years 185±40 mg/dl (total cholesterol), 59±15 mg/dl (free cholesterol), 3.5±1.9 (lipoprotein index), 0.32±0.10 mEq/l (nonesterified fatty acid), 376±85 mg/dl (total fatty acid). 224±80 mg/dl (neutral fat), 186±81 mg/dl (phospholipid), 1.13±0.35 (C/P ratio). Between the two age groups of normotensive subjects there is statistically significant difference in the total cholesterol, free cholesterol and phospholipid. The lipoprotein index, phospholipid, neutral fat, free fatty acid and total fatty acid have a tendency to increase with age. But there were two or three of the serum lipid fractions which showed a tendency of decreasing after 70 years of age.

A new micro method for the estimation of serum total fatty acids

(1) A new micro method is described for determination of serum total fatty acids which is based upon extraction of the fatty acids, after hydrolysis, into heptane and titration with standard NaOH. (2) Duplicate estimations on nineteen different serum samples showed differences of between 0.6 and 8.9% (Mean 3.2%). (3) Comparison of the present method with the Stoddard and Drury precipitation method on twelve different serum samples gave slightly lower values with the former with a mean difference of 2.2% (S.E. ± 0.8) between the results. (4) The method gave between 98 and 103% recovery of stearic acid from a standard solution and between 98.5 and 107% from a mixture of stearic acid and serum. (5) The serum fatty acids.

THE EFFECTS OF DIET ON THE BLOOD COAGULATION RESPONSE TO ALIMENTARY LIPÆMIA IN HEALTHY AND ATHEROSCLEROTIC MEN

SummaryThe response of blood clotting to a standard meal of fat was measured in nine healthy young men and in to atherosclerotic older men when the serum lipids in the fasting state were maintained at their usual levels, and after they had been lowered by dietary manipulations.Ingestion of the test meal was followed by an acceleration of clotting in the “Stypven” test and the whole‐blood clotting time (W.B.C.T.), a rise in plasma turbidity, and increases in the concentrations of serum total esterified fatty acids and serum phospholipids. There was no change in the serum cholesterol level.Lowering of the fasting serum lipid levels had no effect on the “Stypven” response in any of the subjects, and had no effect on the response of the W.B.C.T. to the test meal in the healthy controls. However, both the fasting and post‐prandial W.B.C.T. in the atherosclerotic subjects were longer when the serum lipid levels were low.The presence or absence of atherosclerosis was without effect on the response of the “Stypven” test or the W.B.C.T. to alimentary lipæmia, except that lowering of the fasting lipid levels produced a longer post‐prandial W.B.C.T. in the atherosclerotic subjects.There were statistically significant associations between blood clotting and the serum lipid levels and plasma turbidity. In healthy subjects, acceleration of clotting in the “Stypven” test was associated with a rise in plasma turbidity and serum total fatty acid levels, while the W.B.C.T. became shorter as the serum phospholipid levels rose. There was no significant relationship between the two clotting tests. On the other hand, in the atherosclerotics the W.B.C.T. varied with the “Stypven” time, and clotting in both tests was accelerated as the concentrations of particulate and non‐particulate fat increased.It was observed that the longer the W.B.C.T. in the fasting state and the lower the fasting serum lipid levels, the greater was the response of clotting in this test to the fat meal.

Effect of heparin on serum lipids following intravenous administration of fat emulsion in dogs.

SummaryIntravenous infusion of olive oil emulsion produced elevation of serum total fatty acids and possibly total cholesterol, but without consistent changes in lipid phosphorus. Heparin injection simultaneously with fat infusion increased the rate of removal of the intravenously infused fat and lowered serum cholesterol, but produced no significant changes in lipid phosphorus.

Studies on the effect of triton (WR-1339) on guinea pig tissues. I. Lipide chemistry of lung, liver, spleen, adrenals, and blood.

Guinea pigs given three subcutaneous injections of triton WR-1339, 300 mg./kg., at 3 day intervals develop an intense lipemia as evidenced by marked increases in serum phospholipide, free cholesterol, ester cholesterol, neutral fat, and total fatty acids. The total fatty acid content of the lung, liver, and spleen, however, remains unchanged. No qualitative change in the fatty acids of the lung and liver from treated animals could be detected by the methods used. The injection of triton was found to diminish slightly the cholesterol content of the adrenal glands. The implications of these findings are discussed in relation to an understanding of the mechanism involved in the therapeutic action of triton in experimental tuberculosis.

Reversible effects of anticoagulants and protamine on alimentary lipaemia.

1. Injections of heparin or protamine had no statistically significant effect on the total fatty acid content of the plasma of fasting rats.2. The visible lipæmia of rats fed olive oil was abolished by heparin within five minutes of injection. A decrease in total plasma fatty acids was associated with the change. Dextran sulphate had a similar effect.3. The visible lipæmia of rats fed olive oil was increased by protamine within five minutes of injection. An increase in total serum fatty acids was associated with the change.4. Protamine and heparin were mutually antagonistic in their effects on alimentary lipæmia.5. It is suggested that the anti‐alimentary lipæmic activity of heparin was due to the influence of its negatively charged sulphate groups.

A Study of Carbohydrate and Fat Absorption from the Normal and Diseased Intestine in Man

Summary 1.Tween 80 affects the concentrations of total serum fatty acids and total serum phospholipids following a fatty meal. 2.The serum concentrations of total and free cholesterol are not changed following the ingestion of a fatty meal with or without Tween 80. 3.The ingestion of water or Tween 80 alone has no effect on the concentrations of plasma lipids.