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Biomedical subjects

G Alfthan

Publications and source records attributed to G Alfthan.

At least 55 records · Page 3Linked to original sources
PubMed1995

Plasma and lipoprotein lipid peroxidation in humans on sunflower and rapeseed oil diets.

The effects of natural mixed diets on lipid peroxidation were investigated in humans. In the first study, 59 subjects were fed a rapeseed oil-based diet rich in monounsaturated fatty acids (MUFA) and a sunflower oil-based diet rich in polyunsaturated fatty acids (PUFA) in a cross-over manner for three and a half weeks. The lipid peroxidation products in plasma were determined by measuring conjugated dienes and malondialdehyde (MDA). In a second study, plasma thiobarbituric acid reactive substances (TBARS), lipid hydroperoxides, and the susceptibility of very low density lipoprotein+low-density lipoprotein (LDL) to in vitro oxidation were measured from subjects fed similar MUFA and PUFA diets for six weeks diets. No significant differences in plasma MDA or conjugated diene concentrations were found after the rapeseed oil diet or the sunflower oil diet in Study 1. In the second study, a small but significant decrease (P < 0.05) in both lipid hydroperoxides and TBARS was observed in the LDL fraction after the sunflower oil diet. The in vitro oxidation gave opposite results, showing increased oxidation after the sunflower oil diet. Despite a high intake of alpha-tocopherol during the oil periods, no increase in plasma alpha-tocopherol was noticed in either study. The results suggest that moderate changes in the fatty acid composition in the Western-type diet may be adequate to affect lipoprotein susceptibility to oxidation in vitro, but there is considerable disparity with some indices of in vivo lipid peroxidation.

Adolescent↗
PubMed1995

Effects of supplementation of fertilizers on human selenium status in Finland.

The Se concentration of foods can be increased by supplementing fertilizers with soluble Se compounds. In Finland the availability of soil Se for plants is poor owing to the relatively low Se concentration, low pH and high iron content of the soil. Since 1984 multimineral fertilizers have been supplemented with Se (16 mg kg-1 to fertilizers for grain production and 6 mg kg-1 to those for fodder production) in the form of sodium selenate. Within two years a three-fold increase of mean Se intake was observed. The supplementation affected the Se content of all major food groups with the exception of fish. The concomitant human serum Se concentration increased by 70%. In 1990 the amount of Se that was supplemented was reduced to 6 mg kg-1 for all fertilizers. This reduced the mean Se intake by 30% and the serum Se concentration decreased by 25% from the highest levels observed in 1989. Plants take up part of the supplemented selenate and transform it into organic Se compounds, mainly selenomethionine. This affects human nutrition by increasing the Se content of foods of both animal and vegetable origin. According to data obtained in Finland, supplementation of fertilizers with Se is a safe and effective means of increasing the Se intake of both animals and humans that is feasible in countries with relatively uniform geochemical conditions. This kind of intervention requires careful monitoring of the effects on both animal and human nutrition and the environment.

Fertilizers↗
PubMed1995

Antibodies against oxidised low-density lipoprotein in juvenile chronic arthritis.

Enhanced lipid peroxidation, reported to take place in rheumatoid joints and suggested to play a significant role in joint inflammation, led us to study the occurrence of antibodies against oxidised low-density lipoprotein (Ox-LDL Ab) in patients with juvenile chronic arthritis. Enzyme-linked immunosorbent assay was used to detect Ox-LDL Ab and antiphospholipid antibodies (aPL Ab) in sera from 84 patients and 91 controls. Elevated levels of Ox-LDL Ab were found in 14 patients (17%) as opposed to 4 controls (4%; p < 0.01). Similarly, 14 patients had an elevated aPL Ab level and a fairly good correlation between Ox-LDL Ab and aPL Ab (r = 0.52) existed in the patients. The increased frequency of elevated levels of Ox-LDL Ab may reflect lipid peroxidation occurring in rheumatoid joints but crossreactivity with aPL Ab for the induction of Ox-LDL Ab cannot be excluded.

Adolescent↗
PubMed1994

Antibody against oxidized low-density lipoprotein predicting myocardial infarction.

BACKGROUND: Oxidation of low-density lipoprotein is believed to be an important step in the pathogenesis of atherosclerosis. The purpose of the present study was to determine whether antibody against oxidized low-density lipoprotein, reported to be associated with the progression of carotid atherosclerosis, is predictive of cardiac death and nonfatal myocardial infarction. METHODS: Serum samples from 135 cases and their controls, drawn at entry from middle-aged dyslipidemic men participating in the Helsinki Heart Study, a 5-year coronary primary prevention trial with gemfibrozil, were tested for immunoglobulin G class antibodies against oxidized low-density lipoprotein by enzyme-linked immunosorbent assay. RESULTS: The mean antibody level, expressed in optical density units, was significantly higher in cases than in controls (0.412 vs 0.356, P = .002). After adjustment for age, smoking, blood pressure, and high-density lipoprotein cholesterol level, there was a 2.5-fold increased risk (95% confidence interval, 1.3 to 4.9) of a cardiac end point in the highest tertile of antibody level vs the lowest tertile (P = .005 for trend). CONCLUSIONS: Elevated levels of antibodies against oxidized low-density lipoprotein were predictive of myocardial infarction. The effect was independent of low-density lipoprotein cholesterol levels, and the joint effect was additive. Elevated antibody levels modified the effects of classic coronary risk factors.

Adult↗
PubMed1994

Factors affecting the selenium intake of people in Transbaikalian Russia.

The selenium concentration in foods grown and consumed and in plasma, red blood cells, and toenails of people living in the district of Chita in the transbaikalian part of Russia were studied in August 1991. Preliminary results from the area have suggested low selenium intakes and the possible occurrence of cardiomyopathy (Keshan disease) in the population. A low selenium concentration in foods grown locally was found: mean selenium concentration in wheat grains was 1, 5, and 28 micrograms/kg, respectively, in three villages studied, that of oats was between 3-6 micrograms/kg, and of cow's milk 10-27 micrograms/kg dry matter. The selenium concentration of bread was considerably higher, between 87-337 micrograms/kg dry wt, presumably because wheat imported from the US had been used for baking. Occasional samples of pork, beef, and mutton contained between 32-218 micrograms selenium/kg dry wt. Low selenium concentrations were observed in samples of soil and river water. The mean plasma selenium concentration of 52 persons was 1.02 mumol/L, including 33 children and 19 adult subjects. The selenium concentrations in red blood cells and toenails were 1.95 mumol/L and 0.61 mg/kg, respectively. No symptoms of heart disease caused by selenium deficiency were observed. It is concluded that the selenium status of people was fairly good thanks to the contribution to dietary intake of imported wheat with a high selenium content. As the selenium concentration was very low in foods grown in the area, the selenium intake of the population will be reduced to a very low level if only locally produced foods are consumed.

Adolescent↗
PubMed1994

Relation of serum homocysteine and lipoprotein(a) concentrations to atherosclerotic disease in a prospective Finnish population based study.

The relation of serum total homocysteine and lipoprotein(a) (Lp(a)) with the incidence of atherosclerotic disease was investigated among 7424 men and women aged 40-64 years free of atherosclerotic disease at baseline in 1977. During the 9-year follow-up, 134 male and 131 female cases with either myocardial infarction or stroke were identified. For each case a control subject was selected belonging to the same sex and 5-year age group. Serum samples collected in 1977 were stored at -20 degrees C and analyzed in 1991. The mean serum homocysteine concentration of male cases and controls was 9.99 mumol/l and 9.82 mumol/l at baseline and that of female cases and controls 9.58 mumol/l and 9.24 mumol/l, respectively. The median serum Lp(a) concentration of male cases and controls was 73 mg/l and 108 mg/l and that of female cases and controls 113 mg/l and 91 mg/l, respectively. The differences between cases and controls were not statistically significant. There was also no significant association between either homocysteine or Lp(a) and atherosclerotic disease, myocardial infarction or stroke in logistic regression analyses. The odds ratios varied from 1.00 to 1.26 for homocysteine and from 0.81 to 1.06 for Lp(a). The results of this prospective population-based study do not support the hypotheses that serum homocysteine or Lp(a) are risk factors for atherosclerotic disease. The lack of association between serum homocysteine and atherosclerotic disease may be due to the exceptionally low gene frequency predisposing to homocysteinemia in Finland.

Adult↗
PubMed1994

Serum antioxidants and risk of rheumatoid arthritis.

OBJECTIVES: Oxygen free radicals have been implicated as mediators of tissue damage in patients with rheumatoid arthritis (RA). Thus it is possible that several micronutrients acting as antioxidants and free radical scavengers provide protection against RA. Serum alpha-tocopherol, beta-carotene, and selenium were studied for their associations with the risk of RA. METHODS: A case control study was nested within a Finnish cohort of 1419 adult men and women. During a median follow up of 20 years, 14 individuals initially free of arthritis developed RA. Two controls per each incident case were individually matched for sex, age, and municipality. Serum alpha-tocopherol, beta-carotene and selenium concentrations were measured from stored serum samples. An antioxidant index was calculated as the product of the molar concentrations of these three micronutrients. RESULTS: Elevated risks of RA were observed at low levels of alpha-tocopherol, beta-carotene and selenium, but none of the associations were statistically significant. A significant association, however, was observed with a low antioxidant index (p for trend = 0.03), the relative risk of RA between the lowest tertile and the higher tertiles of its distribution being 8.3 (95% confidence interval 1.0-71.0). CONCLUSIONS: The results of the present study are in line with the hypothesis that a low antioxidant level is a risk factor for RA.

Adult↗
PubMed1993

Crossreaction between antibodies to oxidised low-density lipoprotein and to cardiolipin in systemic lupus erythematosus.

Serum lipoproteins contain phospholipids and modified low-density lipoprotein (LDL) may thus act as a target for antiphospholipid antibodies. Raised concentrations of IgG antibodies against oxidised LDL were found in 47 of 61 (80%) patients with systemic lupus erythematosus (SLE). 46% of patients also had raised concentrations of IgG anticardiolipin antibodies. Binding of anticardiolipin antibodies to solid-phase cardiolipin was inhibited by oxidised LDL but not by native LDL in 16 of 21 sera from SLE patients. These observations suggest crossreactivity between antiphospholipid antibodies, which are closely associated with thrombosis in SLE, and antibodies to oxidised LDL, thus providing a possible link between thrombotic and atherosclerotic complications in SLE.

Adult↗
PubMed1993

Toenail selenium as an indicator of selenium intake among middle-aged men in an area with low soil selenium.

Toenail selenium concentration has been proposed as a long-term (6-12 mo) indicator of human selenium status. This study investigated the association between toenail selenium concentration and selenium intake and other dietary factors among 166 urban men aged 55-69 y. The dietary information was collected by food records covering a 6-mo period. Toenail clippings were collected by mail 9-10 mo after food recording. The mean selenium intake from food was 42.5 micrograms/d and the dietary intake was equal to that of users and nonusers of selenium supplements. The mean toenail selenium concentration was 0.47 mg/kg. The mean selenium intake from supplements was 29.7 micrograms/d among supplement users. In the analysis of covariance the best predictors of toenail selenium concentration were selenium intake from supplements and food, and among supplement users dietary beta-carotene also.

Aged↗
PubMed1993

New method to assess dilution of secretions for immunological and microbiological assays.

Accurate quantitation of pathogens and antibody concentrations in secretions has been difficult because of unpredictable dilution of secretion with th diluent at the time of sample collection. We added an inert substance, lithium chloride (LiCl), to the sample diluent and measured its concentration with an atomic absorption spectrometer before and after the specimen was added. LiCl, at a concentration of 2 mmol of Li per liter, has no negative effect on the survival of common respiratory pathogens or on the results of immunoassays. The method is applicable to any sample collecting in which dilution of the specimen is necessary.

Antibodies↗
PubMed1992

Selenium in Hungary. The rock-soil-human system.

Selenium (Se) status of Hungarian rock-soil systems has been poorly investigated. The goal of this study was to get general information on the main features of Se geochemistry, and to have a brief look into the human Se status in Hungary, developing an appropriate method for a forthcoming systematic regional investigation. A multistage program was applied: 1. stream sediment sampling; 2. investigation of rock-soil profiles typical in Hungary; and 3. extraction of mobile Se fractions from soils. Human serum samples from apparently healthy blood donors residing in both urban and rural areas were collected from three districts in Hungary. It was concluded that Hungarian rock-soil systems, especially the acid igneous rocks and the widely distributed young sediments (loess and sand formations) with most of the agricultural activity, are low in Se, and the mean serum Se level of the blood samples were also low.

Animals↗
PubMed1992

Traditional risk-factor profile fails to explain striking geographical differences in IHD mortality among middle-aged men. The project "myocardial infarction in mid-Sweden".

An east-west gradient in cardiovascular mortality has been reported from the region of mid-Sweden. Postal questionnaire studies found that the risk factor distributions among middle-aged men were similar in areas with striking differences in cardiovascular mortality. In this study, 120 randomly selected 50-year-old men in two high mortality communities in the west and 120 men from two low mortality communities in the east were invited to a health survey in which serum lipids and other risk factors were analysed. Total serum cholesterol, LDL-cholesterol, HDL-cholesterol, and triglyceride levels were similar. Among fatty acids, stearic acid was high and arachidonic acid was low in the high mortality area. The levels of other traditional risk factors were the same. After taking these differences into account, the mortality differences remain large.

Coronary Disease↗
PubMed1992

The human selenium status in Hungary.

The selenium concentration of foods and of human blood varies widely between geographical areas depending on the availability of soil Se for plants. The mean serum Se concentration in Europe has been found to vary between 0.80-1.50 mumol/l and the mean Se concentration of wheat between 0.02-0.11 mg/kg. We estimated by various markers the Se status of Hungarians on whom data is lacking. Serum samples (n = 238) from healthy blood donors, and toenails (n = 132) and fingernails (n = 211) from different apparently healthy individuals residing in both urban and rural areas were collected from four districts in Hungary. Wheat samples (n = 29) as grains were obtained directly from farms representing the same areas. Serum Se was determined by electrothermal AAS and the other samples by acid-digestion fluorimetry. The accuracy of the methods was verified by analyzing external reference samples. The mean (+/- SD) serum Se concentration was 0.70 +/- 0.12 mumol/l, ranging between 0.41-1.18 mumol/l. The mean serum Se levels 0.87 mumol/l was significantly (p < 0.001) higher in the East and lower in the South (0.60 mumol/l) compared to the northern area 0.70 mumol/l. The mean (+/- SD) toenail Se concentration was 0.56 +/- 0.18 mg/kg. The Se level in the East was significantly (p < 0.01) higher than the level in the North, 0.68 mg/kg vs. 0.54 mg/kg, respectively, and lowest in the southern area, 0.40 mg/kg. The same pattern applied to fingernails. Wheat Se ranged from 5 to 235 micrograms/kg, with the median 34 micrograms/kg. The lowest Se concentrations were generally found in the South.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1992

Relationships between myocardial macrominerals and trace elements and luminal narrowing of coronary arteries in Finnish children.

In addition to the traditional risk factors for cardiovascular diseases it has been hypothesized that a suboptimal intake of macrominerals and trace elements plays a role in the etiology of such diseases. We studied the possible correlation between preatherosclerotic changes in the coronary arteries and the myocardial concentration of K, Ca, Mg, Fe, Zn, Cu and Se in an autopsy series of children who had died mainly from accidental causes (n = 58). The concentrations of myocardial elements were comparable to values published elsewhere except for a slightly higher Cu concentration. The myocardial Se concentration indicated an adequate Se status. Narrowing of the coronary artery lumen was not correlated with myocardial element concentration except in the case of Se, for which a positive correlation was found (r = 0.23, p less than 0.04). Myocardial K was positively correlated with myocardial Mg (r = 0.65, p less than 0.001) and inversely correlated with Ca (r = -0.50, p less than 0.001). The intake of saturated vs. unsaturated fats was associated with myocardial Cu and Ca concentrations. Our results suggest that myocardial macrominerals and trace elements do not play a role in juvenile preatherosclerotic changes of the arteries.

Adolescent↗
PubMed1991

Serum micronutrients and risk of cancers of low incidence in Finland.

The associations between serum alpha-tocopherol, beta-carotene, retinol, retinol-binding protein, and selenium levels and the subsequent occurrence of different cancers of low incidence were investigated in a nested case-control study of 39,268 men and women participating in the Social Insurance Institution's Mobile Clinic Health Examination Survey in Finland. During follow-up from the baseline in 1968-1972 to the end of 1977, a total of 115 cancers of the lip, oral cavity, pharynx, larynx, esophagus, liver, gallbladder, kidney, urinary bladder, brain, and skin were reported to the nationwide Finnish Cancer Registry. Alpha-tocopherol, beta-carotene, retinol, retinol-binding protein, and selenium concentrations were determined from stored serum samples collected from these cancer cases and matched controls at baseline. Several sites indicated an elevated risk of cancer at low levels of the serum variables, although only a few of these associations were statistically significant. Only melanoma patients had significantly lower serum alpha-tocopherol and beta-carotene levels than corresponding controls. Since the numbers of cancer cases were small, no firm conclusions can be drawn from these results until they have been confirmed in studies based on larger cohorts or on pooled data from several small samples.

Adult↗
PubMed1991

Effects of selenium supplementation on blood and urine selenium levels and liver function in patients with primary biliary cirrhosis.

To study the mechanism of the reduced serum selenium concentration in patients with liver damage we administered 200 micrograms (2.53 mumol) selenium daily as selenium-rich yeast to 8 patients with primary biliary cirrhosis and 8 healthy controls over 16 weeks. Initially selenium concentrations in serum were 24% lower (P less than 0.001) in patients than controls. During supplementation serum selenium levels increased in both groups but the difference between them persisted. Throughout the study whole blood selenium levels and glutathione peroxidase activities were also somewhat lower (P = NS) in patients than controls. Selenium supplementation had no effect on whole blood glutathione peroxidase activities in either group. The basal 24 h urinary excretion of selenium was similar in both groups but was increased more by supplementation in patients than controls. Selenium administration did not influence the liver function of the patients. We conclude that impaired hepatic production of selenium-containing serum compounds is the most likely explanation for the reduced serum selenium concentration in patients with primary biliary cirrhosis.

Adult↗
PubMed1991

Selenium metabolism and platelet glutathione peroxidase activity in healthy Finnish men: effects of selenium yeast, selenite, and selenate.

The mean dietary selenium intake in Finland increased from 40 to 100 micrograms/d in 1987 because of the addition in 1985 of selenium to fertilizers. A selenium-supplementation study was performed in 1987 on the same men as were followed in a 1981 study that had a similar design (200 micrograms Se/d). Selenite and selenate, but not selenium yeast increased platelet glutathione peroxidase (GSHPx) activity by 30% compared with placebo, much less than the 70% found in the previous study. Selenium yeast and selenite increased plasma selenium after 11 wk from 1.39 mumol/L to peak values of 2.15 and 1.58 mumol/L, respectively. Only yeast selenium was incorporated into red cells. From a regression plot based on present and literature data, it was estimated that the plasma selenium concentration needed to achieve maximal platelet GSHPx activity was 1.25-1.45 mumol/L. At the present selenium intake in Finland, 100 micrograms/d, GSHPx activity is saturated in plasma and red cells and almost saturated in platelets.

Analysis of Variance↗