Wavelength dependence of skin cancer induction by ultraviolet irradiation of albino hairless mice

BACKGROUND: Because of the inverse relation between dietary fish consumption and coronary heart disease and because of the importance of serum homocysteine as an independent risk factor for atherosclerosis, the effect of fish oil on serum homocysteine was studied in hyperlipemic men. METHODS: Fifteen men with either type IIa or IIb lipoproteinemia or hypertriglyceridemia were maintained on a controlled, balanced diet and given either fish oil or olive oil supplements, 12 g/d for 3 weeks, followed by a cross-over period of 3 weeks during which the olive oil or fish oil supplements were given in reverse order. Serum homocysteine was determined by liquid chromatography of acid hydrolyzates of whole serum. RESULTS: Fish oil was found to diminish serum homocysteine levels in 14 of 17 subjects (P < 0.01). Serum homocysteine was 48% +/- 33% less than control values in seven of nine patients and 36% +/- 22% less than values in seven of eight subjects who had first received olive oil. There was no effect of olive oil supplements on serum homocysteine, compared with control values, but olive oil produced an increase in serum homocysteine in those who had first received fish oil. Serum triglycerides and very low-density lipoprotein were decreased by fish oil in patients who were first given olive oil, in agreement with previous studies. There was no effect of either fish oil or olive oil on total cholesterol, apolipoprotein B, low-density lipoprotein, or high-density lipoprotein. CONCLUSIONS: The protection against coronary heart disease afforded by a diet rich in fish may be attributed to the lowering of serum homocysteine levels by the n-3 polyunsaturated fatty acids of fish oils.     

Fish oil supplementation prevents diabetes-induced nerve conduction velocity and neuroanatomical changes in rats

Diabetic neuropathy has been associated with a decrease in nerve conduction velocity, Na,K-ATPase activity and characteristic histological damage of the sciatic nerve. The aim of this study was to evaluate the potential effect of a dietary supplementation with fish oil [(n-3) fatty acids] on the sciatic nerve of diabetic rats. Diabetes was induced by intravenous streptozotocin injection. Diabetic animals (n = 20) were fed a nonpurified diet supplemented with either olive oil (DO) or fish oil (DM), and control animals (n = 10) were fed a nonpurified diet supplemented with olive oil at a daily dose of 0.5 g/kg by gavage for 8 wk. Nerves were characterized by their conduction velocity, morphometric analysis and membrane Na, K-ATPase activity. Nerve conduction velocity, as well as Na,K-ATPase activity, was improved by fish oil treatment. A correlation was found between these two variables (R = 0.999, P < 0.05). Moreover, a preventive effect of fish oil was observed on nerve histological damage [endoneurial edema, axonal degeneration (by 10-15%) with demyelination]. Moreover, the normal bimodal distribution of the internal diameter of myelinated fibers was absent in the DO group and was restored in the DM group. These data suggest that fish oil therapy may be effective in the prevention of diabetic neuropathy.     

Rice bran oil consumption and plasma lipid levels in moderately hypercholesterolemic humans

The effect of rice bran oil, and oil not commonly consumed in the United States, on plasma lipid and apolipoprotein concentrations was studied within the context of a National Cholesterol Education Panel (NCEP) Step 2 diet and compared with the effects of canola, corn, and olive oils. The study subjects were 15 middle-aged and elderly subjects (8 postmenopausal women and 7 men; age range, 44 to 78 years) with elevated low-density lipoprotein (LDL) cholesterol (C) concentrations (range, 133 to 219 mg/dL). Diets enriched in each of the test oils were consumed by each subject for 32-day periods in a double-blind fashion and were ordered in a Latin square design. All food and drink were provided by the metabolic research unit. Diet components were identical (17% of calories as protein, 53% as carbohydrate, 30% as fat [< 7% as saturated fat], and 80 mg cholesterol/1000 kcal) except that two thirds of the fat in each diet was contributed by rice bran, canola, corn, or olive oil. Mean +/- SD plasma total cholesterol concentrations were 192 +/- 19, 194 +/- 20, 194 +/- 19, and 205 +/- 19 mg/dL, and LDL-C concentrations were 109 +/- 30, 109 +/- 26, 108 +/- 31, and 112 +/- 29 mg/dL after consumption of the rice bran, canola, corn, and olive oil-enriched diets, respectively. Plasma cholesterol and LDL-C concentrations were similar and statistically indistinguishable when the subjects consumed the rice bran, canola, and corn oil-enriched diets and lower than when they consumed the olive oil-enriched diet.(ABSTRACT TRUNCATED AT 250 WORDS)     

Promoter trapping identifies real genes in C. elegans

Rats were fed on a low fat diet or on high fat diets which included coconut oil, olive oil, safflower oil, evening primrose oil or fish oil as the principal fat source. The level of phosphatidylinositol-4, 5-bisphosphate in spleen lymphocytes was unaffected by diet. However, the fish oil diet significantly decreased the concentration of inositol-1,4,5-trisphosphate in stimulated lymphocytes; this concentration was also reduced following olive oil feeding. Diet did not significantly affect the level of phospholipase C-gamma1 in spleen lymphocytes but the tyrosine phosphorylation state of this enzyme in stimulated lymphocytes, as well as that of a range of other proteins, was decreased following feeding the fish oil and, to a lesser extent, the olive oil diets. It is concluded that fish oil feeding appears to result in inhibition of one or more tyrosine kinases.     

Effect of isoenergetic replacement of starch by olive oil and fish oil concentrations of lipids in plasma and lipoprotein fractions in swine

Two experiments with sows were performed to investigate the effect of isoenergetic replacement of starch by fish oil or olive oil on concentrations of lipids in plasma and lipoproteins. The first experiment was based on a cross-over design with three periods, each lasting 16 days. Each sow was fed during one of the periods a basal ration with isoenergetic addition of (1) starch (495 g/d), (2) olive oil (221 g/d), or (3) fish oil (223 g/d) based on energetic requirement for maintainance. The second experiment was based on a cross-over design with eight periods, each lasting 16 days. In the first and in the last periods, each sow was fed the basal ration. In the other six periods, each sow was fed the basal ration with addition of two different amounts of (1) starch (284/568 g/d), (2) olive oil (140/281 g/d), or (3) fish oil (141/282 g/d). The two different amounts of addition were selected to exceed the energetic requirement for maintainance by 25% or 50%. In both experiments blood samples were taken before each change of the ration. In both experiments olive oil elevated the concentration of cholesterol in plasma in comparison with starch. This elevation was due to a large elevation in high-density lipoproteins (HDL), and a slight elevation in low-density lipoproteins (LDL) and very-low density lipoproteins (VLDL). The ratio between HDL and LDL cholesterol was increased by feeding olive oil. The effect of olive oil on concentrations of cholesterol in plasma and lipoproteins was dose-dependent. In both experiments none of the two dietary oils significantly changed concentrations of triglycerides in plasma and lipoproteins. Concentrations of phospholipids in plasma, HDL, and LDL were elevated by olive oil. In both experiments addition of fish oil elevated concentration of cholesterol in plasma due to elevated cholesterol concentration in LDL. Concentration of HDL cholesterol was not changed by fish oil. Thus, the ratio between HDL cholesterol and LDL cholesterol was lowered by fish oil. The effect of fish oil on concentration of cholesterol in plasma and lipoproteins was also dose-dependent. Fish oil had no significant effect on phospholipid concentrations in plasma and lipoproteins. In conclusion, in the present experiment olive oil caused antiatherogenic changes of the lipoprotein profile, whereas fish oil caused proatherogenic changes of the lipoprotein profile.     

The influence of gastric juice acidity on the occurrence of esophageal reflux]

Protective properties of n-3 and n-6 polyunsaturated, monosaturated and saturated fatty acids (respectively, n-3 PUFA, n-6 PUFA, MUFA and SFA) against ethanol induced hemorrhagic gastric mucosal lesions were compared. Female Wistar rats (90-100 g) were fed to four weeks semisyntethic diets containing 9% butter (SFA-diet), 6% butter and 3% olive oil (MUFA-diet), 6% butter and 3% sunflower oil (n-6 PUFA-diet) or 6% butter and 3% concentrate of n-3 PUFA ethyl esters (n-3 PUFA-diet). One group of rats received a non-lipid diet. Under all types of lipid containing diets, development of ethanol-induced hemorrhagic gastric mucosal lesions was reduced in compared with non-lipid diet. Cytoprotective effect of n-3 PUFA-E was greater than MUFA and SFA, but smaller than n-6 PUFA.     

Inhibition of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-induced lung tumorigenesis by dietary olive oil and squalene

Epidemiological studies have suggested that frequent olive oil consumption may be a protective factor against lung cancer formation. Squalene, a characteristic compound in olive oil, is an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity and has been proposed to inhibit the farnesylation of ras oncoproteins. The present study investigated the effect of dietary olive oil and squalene in a mouse lung tumorigenesis model. Female A/J mice were fed AIN-76A diets containing 5% corn oil (control), 19.6% olive oil, or 2% squalene starting at 3 weeks before a single dose of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) (103 mg/kg, i.p.). Animals were maintained on their respective diets throughout the study. At 16 weeks after NNK administration, 100% of the mice in the control group had lung tumors with a tumor multiplicity of 16 tumors per mouse. The olive oil and squalene diets significantly (P < 0.05) decreased the lung tumor multiplicity by 46 and 58%, respectively. The squalene diet significantly (P < 0.05) decreased lung hyperplasia by 70%. In mice fed a diet containing 2% squalene for 3 weeks, the activation of NNK was increased by 1.4- and 2.0-fold in lung and liver microsomes, respectively, but its relationship to the inhibition of carcinogenesis is not clear. These results demonstrate that dietary olive oil and squalene can effectively inhibit NNK-induced lung tumorigenesis.     

Incorporation of n-3 fatty acids into plasma lipid fractions, and erythrocyte membranes and platelets during dietary supplementation with fish, fish oil, and docosahexaenoic acid-rich oil among healthy young men

The effects of n-3 fatty acid supplementation in the form of fresh fish, fish oil, and docosahexaenoic acid (DHA) oil on the fatty acid composition of plasma lipid fractions, and platelets and erythrocyte membranes of young healthy male students were examined. Altogether 59 subjects (aged 19-32 yr, body mass index 16.8-31.3 kg/m2) were randomized into the following diet groups: (i) control group; (ii) fish diet group eating fish meals five times per week [0.38 +/- 0.04 g elcosapentaenoic acid (EPA) and 0.67 +/- 0.09 g DHA per day]; (iii) DHA oil group taking algae-derived DHA oil capsules (1.68 g/d DHA in triglyceride form); and (iv) fish oil group (1.33 g EPA and 0.95 g DHA/d as free fatty acids) for 14 wk. The fatty acid composition of plasma lipids, platelets, and erythrocyte membranes was analyzed by gas chromatography. The subjects kept 4-d food records four times during the study to estimate the intake of nutrients. In the fish diet, in DHA oil, and in fish oil groups, the amounts of n-3 fatty acids increased and those of n-6 fatty acids decreased significantly in plasma lipid fractions and in platelets and erythrocyte membranes. A positive relationship was shown between the total n-3 polyunsaturated fatty acids (PUFA) and EPA and DHA intake and the increase in total n-3 PUFA and EPA and DHA in all lipid fractions analyzed. DHA was preferentially incorporated into phospholipid (PL) and triglyceride (TG) and there was very little uptake in cholesterol ester (CE), while EPA was preferentially incorporated into PL. and CE. The proportion of EPA in plasma lipids and platelets and erythrocyte membranes increased also by DHA supplementation, and the proportion of linoleic acid increased in platelets and erythrocyte membranes in the DHA oil group as well. These results suggest retroconversion of DHA to EPA and that DHA also interferes with linoleic acid metabolism.     

Cortical influences on cervical motoneurons in the rat: recordings of synaptic responses from motoneurons and compound action potential from corticospinal axons

Restenosis after successful coronary angioplasty (PTCA) occurs in 25-35% of all procedures. To date, most pharmacologic strategies have failed to reduce the restenosis rate significantly. However, recent studies have suggested a potential benefit of dietary supplementation with omega-3 fatty acids (fish oil) on restenosis following PTCA. The benefit of omega-3 polyunsaturated fatty acids on the incidence of coronary artery restenosis following elective PTCA was assessed in 212 consecutive patients (41 female, 171 male). Following a successful angioplasty, 204 patients received a dietary supplementation with either nine capsules containing fish oil (3.15 g omega-3 fatty acids) or nine placebo capsules containing olive oil. Treatment was started immediately after PTCA and maintained over 4 mon. Compliance was assessed by analysis of lipid fatty acids prior to angioplasty and at 4 mon follow-up. The angiographically determined incidence of restenosis (stenosis diameter > 50%) was 31.2% per lesion in patients receiving fish oil and 33.7% in patients receiving olive oil. Gross progression of coronary artery disease in vessels not subjected to angioplasty was 17% and 16%, respectively. In conclusion, low dose fish oil supplementation begun on the day of a successful coronary angioplasty failed to demonstrate any effect on coronary artery restenosis.     

Quality of care in outpatient clinic for female diseases. A study of the perception of patients with infertility problems

Influence of dietary w-6 and w-3 polyunsaturated fatty acids (PUFA), monounsaturated fatty acids (MUFA) and saturated fatty acids (SFA) on development of rat paw edema induced by dextran subplantar injection was studied. Female Wistar rats the initial weight 150-160 g were bed fo four weeks diets containing as lioid components 6% butter and 3% sunflower oil (w-6 PUFA-diet), 6% butter and 3% fish oil (w-3 PUFA-diet), 6% butter and 3% olive oil (MUFA-diet) or butter (SFA-diet). One group of rats received a non-lipid diet. The development of rat paw edema was reduced under the w-3 PUFA-diet in comparison with the w-6 PUFA-diet, but more intensive then under the non-lipid diet. No differences were detected in effects on inflammation induced w-3 PUFA-, MUFA-, and SFA-diets.     

The influence of dietary fatty acid composition on N-ethyl-N-nitrosourea-induced mammary tumour incidence in the rat and on the composition of inositol- and ethanolamine-phospholipids of normal and tumour mammary tissue

This study has investigated the influence of dietary fatty acid composition on mammary tumour incidence in N-ethyl-N-nitrosourea (ENU)-treated rats and has compared the susceptibility to dietary fatty acid modification of the membrane phospholipids phosphatidylinositol (PI) and phosphatidylethanolamine (PE) from normal and tumour tissue of rat mammary gland. The incidence of mammary tumours was significantly lower in fish oil--(29%), compared with olive oil--(75%; P < 0.04) but not maize oil--(63%; P < 0.1) fed animals. No differences in PI fatty acid composition were found in normal or tumour tissue between rats fed on maize oil, olive oil or fish oil in diets from weaning. When normal and tumour tissue PI fatty acids were compared, significantly higher amounts of stearic acid (18:0) were found in tumour than normal tissue in rats given olive oil (P < 0.05). A similar trend was found in animals fed on maize oil, although differences between normal and tumour tissue did not reach a level of statistical significance (P < 0.1). In mammary PE, maize oil-fed control animals had significantly higher levels of linoleic acid (18:2n-6) than either olive oil- or fish oil-fed animals (P < 0.05, both cases) and levels of arachidonic acid were also higher in maize oil- compared with fish oil-fed animals (P < 0.05). In tumour-bearing animals no differences in PE fatty acid composition were found between the three dietary groups. When normal and tumour tissue PE fatty acids were compared, significantly lower amounts of linoleic acid (18:2n-6; P < 0.01) and significantly greater amounts of arachidonic acid (20:4n-6; P < 0.05) were found in tumour than normal tissue of rats fed on maize oil. The present study shows that the fatty acid composition of PI from both normal and tumour tissue of the mammary gland is resistant to dietary fatty acid modification. The PE fraction is more susceptible to dietary modification and in this fraction there is evidence of increased conversion of linoleic acid to arachidonic acid in tumour compared with normal tissue. Lower tumour incidence rates in rats given fish oils may in part be due to alteration in prostanoid metabolism secondary to displacement of arachidonic acid by eicosapentaenoic acid, but PE rather than PI would appear to be the most likely locus for diet-induced alteration in prostanoid synthesis in this tissue. Effects of dietary fatty acids other than on the balance of n-6 and n-3 fatty acids, and on prostanoid metabolism, should also be considered. The significance of increased stearic acid content of PI in tumours of olive oil-fed animals and the possible influence of dietary fatty acids on the capacity for stearic acid accumulation requires further study.     

The effect of changes in perfusion pressure on uteroplacental blood flow in the pregnant rabbit

The effect of perfusion pressure on uteroplacental blood flow was determined in pregnant rabbits utilizing the radioactive microsphere method. Control mean arterial pressure, 93 mm Hg +/- 2.6 SEM, was raised by carotid ligation to 109 +/- 4.1 mm Hg and then reduced with antihypertensive drugs to 74 +/- 1.3 mm Hg. Over this range of pressure there was no significant change in cardiac output, 605 +/- 36, 523 +/- 37, and 540 +/- 39 ml/min; or uteroplacental blood flow, 30 +/- 3.2, 27 +/- 5.2, and 29 +/- 4.5 ml/min, respectively. When prostaglandin synthesis was inhibited with either indomethacin or meclofenamate (2 mg/kg), uterine vascular resistance was higher but maintenance of uteroplacental flow occurred over a perfusion pressure of 89 +/- 6.7-115 +/- 9.3 mm Hg. With more severe hypotension induced with trimethaphan, control arterial pressure fell from 92 +/- 2.4 to 39 +/- 0.9 mm Hg, cardiac output fell from 514 +/- 17 to 407 +/- 22 ml/min (P less than 0.025) and uteroplacental blood flow fell from 6.1 +/- 0.9 to 2.5 +/- 0.9% of cardiac output (P less than 0.05), which represented an absolute fall from 32.4 +/- 5 to 10.6 +/- 3 ml/min (P less than 0.025). There was no significant change in renal blood flow expressed as percentage of cardiac output, 14.9 +/- 2 and 13 +/- 1.5%, or in absolute flow, 75 +/- 7.7 and 54 +/- 7 ml/min with trimethaphan-induced hypotension. These studies indicate that uteroplacental blood flow is maintained relatively constant over a range of perfusion pressure of 60-140 mm Hg in both normal and prostaglandin-inhibited pregnant rabbits. However, with reduction in pressure to 36-42 mm Hg, uteroplacental blood flow falls, expressed as a percentage of cardiac output and in absolute flow.     

Effects of high-dose fish oil on rheumatoid arthritis after stopping nonsteroidal antiinflammatory drugs. Clinical and immune correlates

OBJECTIVE: To determine the following: 1) whether dietary supplementation with fish oil will allow the discontinuation of nonsteroidal antiinflammatory drugs (NSAIDs) in patients with rheumatoid arthritis (RA); 2) the clinical efficacy of high-dose dietary omega 3 fatty acid fish oil supplementation in RA patients; and 3) the effect of fish oil supplements on the production of multiple cytokines in this population. METHODS: Sixty-six RA patients entered a double-blind, placebo-controlled, prospective study of fish oil supplementation while taking diclofenac (75 mg twice a day). Patients took either 130 mg/kg/day of omega 3 fatty acids or 9 capsules/day of corn oil. Placebo diclofenac was substituted at week 18 or 22, and fish oil supplements were continued for 8 weeks (to week 26 or 30). Serum levels of interleukin-1 beta (IL-1 beta), IL-2, IL-6, and IL-8 and tumor necrosis factor alpha were measured by enzyme-linked immunosorbent assay at baseline and during the study. RESULTS: In the group taking fish oil, there were significant decreases from baseline in the mean (+/- SEM) number of tender joints (5.3 +/- 0.835; P < 0.0001), duration of morning stiffness (-67.7 +/- 23.3 minutes; P = 0.008), physician's and patient's evaluation of global arthritis activity (-0.33 +/- 0.13; P = 0.017 and -0.38 +/- 0.17; P = 0.036, respectively), and physician's evaluation of pain (-0.38 +/- 0.12; P = 0.004). In patients taking corn oil, no clinical parameters improved from baseline. The decrease in the number of tender joints remained significant 8 weeks after discontinuing diclofenac in patients taking fish oil (-7.8 +/- 2.6; P = 0.011) and the decrease in the number of tender joints at this time was significant compared with that in patients receiving corn oil (P = 0.043). IL-1 beta decreased significantly from baseline through weeks 18 and 22 in patients consuming fish oil (-7.7 +/- 3.1; P = 0.026). CONCLUSION: Patients taking dietary supplements of fish oil exhibit improvements in clinical parameters of disease activity from baseline, including the number of tender joints, and these improvements are associated with significant decreases in levels of IL-1 beta from baseline. Some patients who take fish oil are able to discontinue NSAIDs without experiencing a disease flare.     

Effect of dietary fats rich in lauric, myristic, palmitic, oleic or linoleic acid on plasma, hepatic and biliary lipids in cholesterol-fed hamsters

Effects of different dietary fats on plasma, hepatic and biliary lipids were determined in male golden Syrian hamsters (Mesocricetus auratus) fed on purified diets for 7 weeks. Diets were made by blending different fats containing characteristic fatty acids: butter (14:0 + 16:0), palm stearin (16:0), coconut oil (12:0 + 14:0), rapeseed oil (18:1), olive oil (18:1) and sunflowerseed oil (18:2). In all diets except the sunflowerseed oil diet dietary 18:2 was held constant at 2% energy. Total fat supplied 12% of energy and cholesterol was added at 4 g/kg diet. Plasma cholesterol and triacyglycerol concentrations were increased by dietary cholesterol. After 7 weeks, plasma cholesterol concentrations were highest with the palm stearin, coconut oil and olive oil diets (8.9, 8.9 and 9.2 mmol/l) and lowest with the rapeseed oil and sunflowerseed oil diets (6.7 and 5.5 mmol/l) while the butter diet was intermediate (8.5 mmol/l). Hepatic cholesterol concentration was highest in hamsters fed on the olive oil diet and lowest with the palm stearin diet (228 v. 144 mumol/g liver). Biliary lipids, lithogenic index and bile acid profile of the gall-bladder bile did not differ significantly among the six diets. Although the gallstone incidence was generally low in this study, three out of 10 hamsters fed on the palm stearin diet developed cholesterol gallstones. In contrast, no cholesterol gallstones were found with the other diets. Rapeseed and sunflowerseed oils caused the lowest plasma cholesterol and triacyglycerol concentrations whereas olive oil failed to demonstrate a cholesterol-lowering effect compared with diets rich in saturated fatty acids. Since 18:2 was kept constant at 2% of energy in all diets, the different responses to rapeseed and olive oils could possibly be attributed to their different contents of 16:0 (5.6% v. 12.8% respectively). Other possible explanations are discussed.     

Effects of pancreatic polypeptide amylin on ulceration and acid gastric secretion

The effects of the pancreatic polypeptide amyline on ulceration and acid gastric secretion were studied in rat experiments. Pyloric ligation was used as a model of ulceration. Amyline administration caused significantly less gastric mucosal damage in response to pyloric ligation. The severity of gastric mucosal damage averaged 47 +/- 13 mm2 in the control group and 25 +/- 11 mm2 (p < 0.005). The rate of acid gastric secretion in the animals whose pylorus had been ligated as judged by the pH of gastric content was significantly higher than that in the controls (2.87 +/- 0.22 and 2.34 +/- 0.17 (p = 0.05). It is concluded that amyline has a noticeable effect on the gastric mucosa. It is suggested that suppressed acid gastric secretion, i.e. reduced influence of aggressive agents on the gastric mucosa, is a mechanism of antiulcerative action of the peptide.     

Pharmacological and pharmaceutical properties of freeze-dried formulations of egg albumin, indomethacin, olive oil, or fatty acids. II

To confirm the increased bioavailability of indomethacin (IND) when incorporated in a preparation with egg albumin and olive oil, we studied the detailed pharmaceutical characteristics of a ternary formulation consisting of egg albumin, IND and olive oil. From the results of X-ray powder diffraction measurements, the drug in the formulation was found to be in an amorphous form. When orally administered to rats, the ternary formulation significantly increased the plasma concentration and cumulative biliary and urinary excretion of IND alone as well as the urinary excretion of its major metabolite, desmethylindomethacin, compared with the drug alone. In addition, the dissolution rate of IND from the formulation was higher than that of the drug alone. These results clearly suggest that the bioavailability of IND was markedly improved by incorporating it in a protein-drug formulation containing olive oil as an absorbefacient element, and this effect may be due to an increased absorption of IND.     

The effect of fish oil on blood pressure and high-density lipoprotein-cholesterol levels in phase I of the Trials of Hypertension Prevention. Trials of Hypertension Prevention Collaborative Research Group

OBJECTIVE: To study the effects of moderate doses of fish oil on blood pressure and high-density lipoprotein (HDL)-cholesterol. METHODS: The participants were 350 normotensive men and women aged 30-54 years who were enrolled from seven academic medical centers in phase I of the Trials of Hypertension Prevention. They were randomly assigned to receive placebo or 6 g purified fish oil once a day, which supplied 3 g n-3 polyunsaturated fatty acids for 6 months. RESULTS: Baseline blood pressure was (mean +/- SD) 123 +/- 9/81 +/- 5 mmHg. The mean differences in the blood pressure changes between the fish oil and placebo groups were not statistically significant. There was no tendency for fish oil to reduce blood pressure more in subjects with baseline blood pressures in the upper versus the lower quartile (132/87 versus 114/75 mmHg), low habitual fish consumption (0.4 versus 2.9 times a week) or low baseline plasma levels of n-3 fatty acids. Fish oil increased HDL2-cholesterol significantly compared with the placebo group. Subgroup analysis showed this effect to be significant in the women but not in the men. Increases in serum phospholipid n-3 fatty acids were significantly correlated with increases in HDL2-cholesterol and decreases in systolic blood pressure. CONCLUSION: Moderate amounts of fish oil (6 g/day) are unlikely to lower blood pressure in normotensive persons, but may increase HDL2-cholesterol, particularly in women.     

Prevalence of antibodies against virus-like particles of Epidermodysplasia verruciformis-associated HPV8 in patients at risk of skin cancer

The dietary intake of saturated fatty acids affects arteriosclerosis. We studied the effect of supplementation (15% wt/wt) of a hyperlipemic diet (1.3% cholesterol) with evening primrose oil (Oenothera biennis) in four groups of 10 rabbits each. After 6 weeks the aortic endothelium was analyzed morphologically with scanning electron microscopy, and the arterial wall was studied with morphometric techniques and cell nucleus counts. Endothelial functioning was analyzed by measuring prostacyclin synthesis, and thrombogenicity of the subendothelium was studied by perfusion in a Baumgartner annular chamber. Evening primrose oil reduced hypercholesterolemia (from 29 +/- 3 to 12 +/- 2 nmol/l), increased HDL-cholesterol (from 0.5 +/- 0.06 to 0.8 +/- 0.09 nmol/l) and doubled prostacyclin synthesis (from 2.7 +/- 2 to 6.2 +/- 0.7 ng/mg aorta) in rabbits on the hyperlipemic diet, reduced subendothelial surface occupied by platelets (from 6.9 +/- 0.4 to 4.8 +/- 0.3%), and reduced human platelet adhesion on the subendothelium (from 53.3 +/- 6% to 38 +/- 8%, respect to total occupation). Morphological analyses showed that evening primrose oil diminished endothelial lesions caused by the atherogenic diet, reducing area of the arterial wall (from 6.9 +/- 0.2 to 4.7 +/- 0.2 microm2 x 10(6)) and the degree of neointimal proliferation (from 0.6 +/- 0.02 to 0.4 +/- 0.09 microm2 x 10(6)). We conclude that in our experimental model, this dietary supplement enhanced the antithrombotic capacity of the endothelium, reduced subendothelial thrombogenicity, and diminished the extent of vascular wall lesions caused by the hyperlipemic diet.     

Dietary fish oil does not alter glucose tolerance in conscious rats

We examined the effect of dietary fish oil (MaxEPA) and sunflower seed oil on glucose tolerance in male Wistar rats. Semipurified diets containing 100 g oil/kg diet were administered for 30 d. The fish oil diet contained 26 g (n-3) fatty acids, 16 g eicosapentaenoic acid and 10.4 g docosahexaenoic acid/kg diet. Phospholipids from liver, pancreas, and pancreatic islets were enriched in eicosapentaenoic and docosahexaenoic acids by the fish oil diet. In unfed pentobarbital-anesthetized rats, both basal plasma insulin concentration and insulin responses to intravenous glucose were significantly lower for fish oil-fed rats although glucose responses were similar; however, incremental excursions in plasma insulin over the basal concentrations did not differ. Intravenous glucose tolerance was also examined in conscious unfed rats under minimal restraint. Responses of plasma glucose and insulin were similar for fish oil- and sunflower oil-fed groups. Furthermore, in another experiment, intravenous glucose tolerance tests were similar for conscious rats provided with either 100 g fish oil or corn oil/kg nonpurified diet. Thus, glucose-induced insulin secretion is lower in rats fed fish oil than in rats fed sunflower oil, when tests are conducted in pentobarbital-anesthetized animals but not when tests are performed in conscious rats; there was no effect on plasma glucose in either anesthetized or nonanesthetized rats. Therefore, substitution of (n-3) for (n-6) polyunsaturated fatty acids in tissue phospholipids does not alter plasma glucose or insulin in conscious male Wistar rats.     

Modulation of exercise-induced immunosuppression by dietary polyunsaturated fatty acids in mice

The possible interaction between intense exercise, known to suppress the immune response, and nutritive factors, such as polyunsaturated fatty acids (PUFA), was examined in inbred female C57Bl/6 mice. The animals received for 8 wk either a natural ingredient diet or a diet supplemented with 10 g/100 g linseed oil containing over 50% of 18:3 (n-3) alpha-linoleic acid. Other groups received PUFA containing only traces of 18:3 (n-3) fatty acid; beef tallow, containing mostly 18:1 (n-9) saturated fat, safflower oil, an 18:2 (n-6) PUFA, and fish oil, containing longer chain (n-3) PUFA. Each dietary group was divided into two subgroups: sedentary diet controls and exercised animals. Exercise consisted of continuous swimming at high intensity until exhaustion. It was shown in three separate experiments that (1) the primary humoral response to sheep red blood cells, determined by the plaque-forming cell (PFC) assay, was affected by PUFA diet in sedentary animals in the order beef tallow > control diet > safflower oil > fish oil > linseed oil, and (2) the PFC response was suppressed by the exhaustive exercise, as compared to sedentary controls, except for animals fed 18:3 (n-3) linseed oil, where the normal response was noted. Phagocytosis of fluorescent microspheres by peritoneal macrophages, determined by flow cytometry, was significantly lower in exercised animals receiving the linseed oil diet, whereas other diets either increased or did not significantly change the macrophage phagocytic activity, compared to the sedentary diet controls. Spleen lymphocyte subsets were unchanged in exercised animals except for a marked shift from the lymphoid peak toward the erythroid peak. Generally, our data showed a marked immunomodulatory effect of 18-3 (n-3) alpha-linoleic acid on the exhaustive exercise-related immunosuppression, as compared to the effects of other selected PUFA.