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Biomedical subjects

E B Schmidt

Publications and source records attributed to E B Schmidt.

At least 19 recordsLinked to original sources
PubMed1998

Heart rate variability and n-3 fatty acids in patients with chronic renal failure--a pilot study.

Patients with chronic renal failure (CRF) often have autonomic cardiac dysfunction, which can be assessed by measuring heart rate variability (HRV). This dysfunction prediposes the patients to sudden cardiac death. This study describes 24-hour HRV in patients with CRF compared to HRV in patients with a previous myocardial infarction (MI). Furthermore, associations between HRV in patients with CRF and the content of n-3 polyunsaturated fatty acids (PUFA) in cell membranes were examined, because n-3 PUFA may improve HRV. Twenty-nine patients with CRF treated with dialysis were enrolled. A 24-hour Holter recording was obtained at baseline and the HRV variables, RR (= mean of all normal RR intervals during the 24-hour recording) and SDNN (= standard deviation of all normal RR intervals in the entire 24-hour recording) were analyzed. Also, granulocyte fatty acid composition was determined. The patients were allocated to dietary supplementation with either 5.2 g of n-3 PUFA or a placebo oil (olive oil) daily for 12 weeks in a double-blind design. At the end of the supplementation period the Holter recording and blood sampling were repeated. At baseline the CRF patients' mean SDNN ws 86 ms compared to 118 ms (p < 0.01) in patients with a previous MI. After supplementation with either n-3 PUFA or placebo a highly significant correlation was observed between the content of n-3 PUFA in cell membranes and HRV (r = 0.71, p < 0.01). Furthermore, when the patients were dichotomized according to their mean SDNN, it was found, that those with the highest SDNN had a higher content of n-3 PUFA in cell membranes compared to those with the lowest SDNN (7.8% vs 4.2%, p < 0.05). In conclusion, HRV was decreased in CRF patients indicating a cardiovascular autonomic dysfunction. The positive correlation between the n-3 PUFA content in cell membranes and HRV suggests that the effects of an increased intake of n-3 PUFA in CRF patients should be further studied.

Cell Membrane↗
PubMed1997

[n-3 polyunsaturated fatty acids, heart rate variability and ventricular arrhythmias in post-AMI-patients. A clinical controlled trial].

There is evidence for an antiarrhythmic effect of n-3 polyunsaturated fatty acids (n-3 PUFA) in animals. The aim of the present study was to investigate the effect of dietary n-3 PUFA on ventricular arrhythmias and heart rate variability (HRV) in patients with a previous myocardial infarction. Fifty-five patients were randomized to receive either 5.2 g of n-3 PUFA daily for 12 weeks or placebo in a double blind, placebo-controlled study. Prior to randomization a 24-hour Holter recording was obtained, and this was repeated at the end of the study. The major end-points were the number of ventricular extrasystoles (VE)/24 hours and the 24-hour HRV. A non-significant decrease in VE/24 hours was found in both the n-3 PUFA group and among controls after dietary supplementation, whereas HRV significantly increased after n-3 PUFA compared to both baseline values (p = 0.04) and to controls (p = 0.01). The present study therefore supports the hypothesis that n-3 PUFA may have an anti-arrhythmic effect in humans.

Aged↗
PubMed1997

Fish consumption, n-3 fatty acids in cell membranes, and heart rate variability in survivors of myocardial infarction with left ventricular dysfunction.

To elucidate a possible antiarrhythmic effect of long-chained n-3 polyunsaturated fatty acids, heart rate variability was assessed in 52 patients with a previous myocardial infarction and left ventricular dysfunction. The content of n-3 polyunsaturated fatty acids in platelets was closely associated with the patient's fish-consuming habits, and a significant positive correlation was observed between the n-3 fatty acid docosahexaenoic acid and heart rate variability.

Aged↗
PubMed1997

Homocysteine in Greenland Inuits.

Patients with homozygous homocystinuria are at greatly increased risk for development of atherosclerosis and thrombosis (1). Elevated plasma levels of homocysteine (HCY) are caused by reduced enzymatic catabolism or reduced enzymatic remethylation of HCY, due to either hereditary enzyme defects or to nutritional deficiencies of vitamins functioning as cofactors. However, several recent studies have suggested that persons with mildly elevated plasma levels of HCY also are at increased risk for coronary heart disease. (2-4). There are some indications that dietary n-3 polyunsaturated fatty acids (PUFAs) may offer protection against coronary heart disease (5-6). Several mechanisms may be involved, including beneficial effects of n-3 PUFAs on plasma lipids, platelet and leukocyte reactivity, blood pressure and vasoreactivity (7). Interestingly, Olszewski el al. recently found HCY-levels to be lowered 36% in 15 type IIa or IIb hyperlipemic men by n-3 PUFA supplementation. A possible beneficial effect of n-3 PUFA on the incidence of coronary heart disease was initially suggested from studies in Greenland Inuits by our group (8). We therefore investigated plasma levels of homocysteine in a group of traditionally living Greenland Inuits with a diet consisting mainly of marine food and with a very high content of n-3 PUFAs.

Adult↗
PubMed1997

n-3 fatty acids do not decrease plasma endothelin levels in healthy individuals.

The effect of three different doses of n-3 polyunsaturated fatty acids (PUFA) on endothelin-1 (ET-1) was studied. Study 1 included 40 healthy volunteers randomized to a single supplement of 20 g of n-3 or n-6 PUFA. Plasma ET-1 was measured 14 h after ingestion, and no changes in plasma ET-1 after intake of n-3 PUFA were observed, compared to baseline values. In study 2, 32 subjects had 0.65 g of n-3 PUFA or a fat mixture per day for 12 weeks. No changes in plasma ET-1 were found after the oil supplements. Finally, 22 persons had 4 g of n-3 PUFA for 6 weeks. A significant increase in plasma ET-1 was seen in this group after the supplement. Thus, n-3 PUFAs do not lower plasma levels of ET-1, the most potent vasoconstrictor known.

Adult↗
PubMed1996

No effect of a very low dose of n-3 fatty acids on monocyte function in healthy humans.

There is some evidence that intake of sea food rich in n-3 polyunsaturated fatty acids (PUFA) may protect against coronary heart disease (CHD). Thus, even very low daily amounts of n-3 PUFA below 0.5 g have been reported to reduce the incidence of CHD, although it is unknown by what mechanisms this may occur. Monocytes are of major importance in atherogenesis, and we therefore studied the effect of a daily supplement with 0.65 g of n-3 PUFA for 12 weeks on monocyte function in a randomized placebo-controlled trial of 32 healthy subjects. No effect of dietary n-3 PUFA could be demonstrated on monocyte chemotaxis, on chemiluminescence, or on formation of cytokines and leukotriene B4 from activated monocytes.

Adult↗
PubMed1995

n-3 polyunsaturated fatty acids: update 1995.

Epidemiologic and biochemical studies have suggested an anti-inflammatory effect of n-3 fatty acids. Beneficial therapeutic effects reported from small patient groups need to be confirmed in large-cohort controlled clinical trials. There is a growing number of clinical trials of n-3 fatty acid supplementation in disease. Clinical benefits have been moderate in patients with rheumatoid arthritis and with arterial hypertension. Clearly negative results have been reported during the past 2 years for patients with lupus nephritis and for patients with psoriasis or with atopic dermatitis. Such trials have now been completed. For patients with coronary artery disease following coronary angioplasty, earlier results of a large meta-analysis, could not be confirmed. For patients with IgA-nephropathy and for patients following kidney transplantation, a clear benefit was seen in patients receiving fish oil. These promising results are currently pursued in follow-up phase III clinical trials.

Animals↗
PubMed1995

The effect of n-3 fatty acids on neutrophil chemiluminescence.

The effect of dietary supplementation with n-3 polyunsaturated fatty acids (PUFAs) on the production of free oxygen radicals from activated neutrophils was investigated in healthy subjects, using chemiluminescence. In the first study 22 persons were give 4 g n-3 PUFAs daily for 6 weeks. There was a median reduction of chemiluminescence from neutrophils stimulated with opsonized zymosan of 37% (p < 0.001). The median content of eicosapentaenoic acid in platelets, used as an indicator for cellular fatty acid profile, increased from 0.70 to 2.80% (p < 0.001), and there was a significant negative correlation between the chemiluminescence signal and the content of eicosapentaenoic acid in platelets (p < 0.001). In a second, low-dose study 24 persons were allocated to daily supplementation with either 0.65 g n-3 PUFAs or with a control oil for 6 weeks. Compared to the control group there was a median reduction of 38 and 44% in chemiluminescence from neutrophils stimulated with opsonized zymosan and phorbol,12-myristate,13-acetate (PMA), respectively. Neither of these differences, however, was statistically significant. These findings lend support for a possible role of n-3 PUFAs in the management of inflammatory disorders.

Adult↗
PubMed1994

[Fish oils and rheumatoid arthritis].

Dietary supplementation with polyunsaturated fatty acids--n-3 PUFA or fish oils--has gained increasing interest among patients suffering from rheumatoid arthritis. The biochemical background for the beneficial effects of fish oils in modulating the inflammatory response is briefly described and is partly based on findings from experimental animal models. Ten published double-blind studies evaluating the effect of a daily supplement with three to six grams of n-3 PUFA to patients with active rheumatoid arthritis are reviewed. The studies support a modest effect of fish oil on patient-reported disease parameters without serious side effects. Future research should evaluate effect, tolerance and side effects in long term studies with different daily intakes of n-3 PUFA and should also focus on the effect of n-3 PUFA in combination with standard therapy in patients with rheumatoid arthritis.

Animals↗
PubMed1994

[Fish oils and rheumatoid arthritis. A randomized and double-blind study].

The effect of dietary supplementation with n-3 polyunsaturated fatty acids (n-3 PUFA) on disease variables in patients with active rheumatoid arthritis was evaluated in a multicentre, randomized and double blind study. Fifty-one patients with active rheumatoid arthritis were included from three Danish hospital Departments of Rheumatology. The patients were allocated to 12 weeks of treatment with either six n-3 PUFA capsules (3.6 g) or six capsules with a fat composition averaging the Danish diet. Small but significant improvements in morning stiffness, joint tenderness and C-reactive protein were observed. There were no serious side-effects. Dietary supplementation with n-3 PUFA in patients with active rheumatoid arthritis has a modest effect on three out of eight disease variables, without effect on other traditional parameters for monitoring disease activity.

Arthritis, Rheumatoid↗
PubMed1994

The acute effects of a single very high dose of n-3 fatty acids on plasma lipids and lipoproteins in healthy subjects.

Forty healthy volunteers were allocated in a double blind, randomized study to receive either 20 g of n-3 polyunsaturated fatty acids (PUFA) or 20 g of n-6 PUFA at their evening meal. The effect on plasma lipids and lipoproteins of this single dose of fish oil vs. corn oil was studied the next morning, 14 h after ingestion. Plasma triglycerides and very low density lipoprotein-cholesterol significantly decreased (33%) after n-3 PUFA (P < 0.001), and significantly (P < 0.01) more than after intake of n-6 PUFA. The decrease in plasma triglycerides after n-3 PUFA ingestion was more pronounced in subjects with higher baseline levels of triglycerides (P < 0.001). Total cholesterol decreased after both supplements, but did not differ between the supplements. Low density lipoprotein-cholesterol did not change, and high density lipoprotein-cholesterol significantly decreased in subjects given n-3 PUFA compared to baseline, but not when compared to subjects receiving n-6 PUFA. In conclusion, we have shown that a single very high dose of n-3 PUFA has a pronounced hypotriglyceridemic effect, which is directly related to the initial plasma level.

Adult↗
PubMed1994

n-3 fatty acids and renal diseases.

There are numerous biologic rationales for the use of n-3 fatty acids in renal diseases, including a possible increase in the renal vasodilatory capacity by a rearrangement of renal prostanoid production, a reduction in the production of proinflammatory leukotrienes, a reduction in the transcapillary escape rate of albumin, and actions limiting cyclosporine-related nephrotoxicity. Studies of animal models of renal disease, mostly of immune-renal disease, support the idea of the possible usefulness of these compounds. The most promising areas of clinical investigation include the reduction of proteinuria in some chronic glomerular diseases, the treatment of immunoglobulin A nephropathy, and the prevention of cyclosporine-induced nephrotoxicity. However, the results of larger clinical studies, some of which are ongoing, are necessary to support the use of n-3 fatty acids in human renal diseases.

Animals↗
PubMed1994

Omega-3 fatty acids. Current status in cardiovascular medicine.

Omega-3 polyunsaturated fatty acids (PUFA) reduce fasting and postprandial triglycerides, decrease platelet and leucocyte reactivity, and may slightly decrease blood pressure. Omega-3 PUFA may also beneficially influence vessel wall characteristics and blood rheology. Furthermore, these compounds have been shown to inhibit ventricular tachyarrhythmias in animals. Omega-3 PUFA may impair fibrinolysis and could lead to increased oxidation of lipoproteins. Potential adverse effects must not be neglected, but should be viewed in light of the beneficial effects of these agents. Clinical studies investigating the effects of dietary omega-3 PUFA in the prevention and treatment of cardiovascular disease (CVD) are beginning to emerge. The results have offered some promise, but further studies are needed to define the role of these agents in CVD. Long term trials and studies using omega-3 PUFA as adjuvants to conventional therapy in patients with coronary artery disease, hyperlipidaemia and hypertension may be of particular interest.

Animals↗
PubMed1993

The influence of dietary n-3 fatty acids on plasma lipids and lipoproteins.

The body of epidemiologic data indicates that the incidence of cardiovascular disease is lower in populations whose habitual diet is rich in fish. It is unclear however to what extent this apparent protection is due to the intake of n-3 fatty acids in sea food or to the fact that these subjects have generally been consuming lower amounts of saturated fatty acids in their diets. It is clear, however, that when the dietary intake of n-3 fatty acids is increased to 4-8 g/day distinct metabolic effects are observed, including reductions in plasma triglycerides, effects on platelet function and coagulation factors and blood pressure. Larger intakes exert a more profound hypotriglyceridemic effect, and in patients with primary hypercholesterolemia daily intakes exceeding 10-12 g/day are effective in reducing plasma concentrations of LDL cholesterol. However, from a practical point of view, the lipid-modifying effects of supplemental dietary n-3 fatty acids are most clearly observed in patients with hypertriglyceridemia and the major usefulness of dietary n-3 fatty acids is in the treatment of this patient population, particularly patients with severe hypertriglyceridemia or potentially those with Type III hyperlipoproteinemia. Further studies are needed to better define the potential utility of dietary n-3 fatty acids when used in combination with lipid-lowering drugs to reduce lipoprotein concentrations in patients with combined hyperlipoproteinemia or severe hypertriglyceridemia.

Dietary Fats, Unsaturated↗
PubMed1993

Hypocholesterolemic effects of cholestyramine and colestipol in patients with familial defective apolipoprotein B-100.

Familial defective apolipoprotein B-100 (FDB) is a dominantly inherited disorder associated with hypercholesterolemia, in which substitution of the amino acid glutamine for arginine at position 3500 in the apoprotein B molecule results in LDL particles which bind poorly to the LDL receptor. To date, patients with FDB have been heterozygous for this disorder and their plasma contains both normal and defective-binding LDL particles, with a predominance of the latter. In the present report, we have compared the hypocholesterolemic effects of bile acid sequestrant therapy (cholestyramine or colestipol) in eight patients with FDB, to the response seen in sixteen patients with heterozygous familial hypercholesterolemia (FH), treated with the same drugs. Concentrations of LDL cholesterol fell by 32.0% in the patients with FDB and by 21.6% in the patients with FH. The results indicate that the hypercholesterolemia of both FDB and FH responds to treatment with bile acid sequestrants.

Adult↗
PubMed1993

Interobserver variation in interpretation of electrocardiographic signs of atrial infarction.

The electrocardiogram (ECG) is the only means of diagnosing atrial infarction antemortem. Certain ECG changes (PR-segment displacements) have been taken earlier as signs of atrial infarction. The purpose of this study was to assess the interobserver variation on suggested ECG signs of atrial infarction in patients admitted with acute myocardial infarction. The ECGs from 290 patients were evaluated by three physicians with respect to the occurrence of each of the following seven criteria suggestive of atrial infarction: (1) PR-segment elevation > 0.5 mm in lead I; (2) PR-segment depressions > 0.5 mm in leads II and III; (3) PR-segment depressions > 1.2 mm in leads I, II, and III; (4) PR-segment depressions > 0.5 mm in leads V1 and V2; (5) PR-segment elevations > 0.5 mm in leads V5 and V6; (6) PR-segment depressions > 1.5 mm in precordial leads; and (7) abnormal P waves. Kappa values ranged from 0.00-0.86. Of the seven criteria tested only criteria 2, 4, and 7 could be detected in a reasonable number of patients. The interobserver variations of these criteria were considerable, although the strength of agreement could be designated as fair to moderate.

Atrial Function↗