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Biomedical subjects

J Lehto

Publications and source records attributed to J Lehto.

26 records · Page 2Linked to original sources

Element concentrations in serum, erythrocytes, hair and urine of alopecia patients.

The trace element concentrations of Se, Rb, Zn, Fe, Co, Cs, Mg, Ca, F, Cu, Cr and Ag in serum and of Se, Rb, Zn, Fe, Co and Cs in red cells of Finnish alopecia patients were determined. In addition the Cu and Zn content in 24 h urine and Cu, Zn, Cd, Cr and Se concentrations in the hair of these patients were studied. No differences in element concentrations of the samples mentioned above as compared to those of the normal population could be found. In addition, there was no tendency of excesses or deficiences of elements analysed in the samples. Statistically significant difference was found between the copper content of serum in alopecia areata and alopecia universalis patients and also between the copper content of serum in alopecia areata plus alopecia totalis and alopecia universalis patients. The selenium concentration in serum samples of a few patients was low, but this is in agreement with the fact that the selenium content in the Finnish population is low due to the scanty content of selenium in food.

Adolescent↗

Determination of chromium in human milk, serum and urine by electrothermal atomic absorption spectrometry without preliminary ashing.

In the present study a Perkin-Elmer 5000 atomic absorption spectrometer equipped with a tungsten--iodide lamp for improved background correction at the 357.9 nm chromium absorption line and an HGA 500 graphite furnace were employed for the direct determination of chromium in human serum, milk and urine. The method of standard additions was used: 0.25-0.75 ng Cr was added to 1 ml samples. Except for urine samples, a dilution of 1 + 1 to 1 + 2 with H2O was necessary in order to obtain correct calibration curves. The average concentration of chromium in all the samples of normal subjects was less than 0.5 ng Cr ml-1. The day-to-day variation for all of the pooled samples was around 10% (relative standard deviation). For urine, the accuracy of the method was tested by comparing the results of another laboratory for the same two round robin samples. Excellent agreement was found between the present method and those of the other laboratory that had used isotope dilution--mass spectrometry and continuum source wavelength modulated echelle--atomic absorption spectrometry to define the chromium concentration in the samples. The detection limit of the method, 0.05 ng Cr ml-1 for urine and serum and 0.1 ng Cr ml-1 for human milk, was sufficient for the biological fluids analyzed. The method was employed for the determination of chromium in 24-h urine samples of maturity onset diabetics supplemented with 20 or 200 micrograms Cr3+ d-1 for six weeks. It was shown that the 24-h urinary chromium excretion accurately indicates the daily dietary chromium intake of these patients.

Adult↗

Electrothermal atomic absorption spectrometric determination of selenium in foods and diets.

The validity of 2 electrothermal atomic absorption spectrometric methods for determination of selenium in foods and diets was tested. By using 0.5% Ni(II) as a matrix modifier to prevent selenium losses during the ashing step, it was shown that selenium can be determined in samples containing greater than or equal to 1 microgram Se/g dry wt without organic extraction. The mean recovery tested, using NBS Bovine Liver, was 98%; recovery of added inorganic selenium in Bovine Liver matrix was 100%. In addition, this method gave values closest to the median value of all participating laboratories using hydride generation AAS or the spectrofluorometric method in a collaborative study on high selenium wheat, flour, and toast samples. For samples with concentrations less than 1 microgram Se/g dry wt, separation of selenium from interfering Fe and P ions by organic extraction was necessary. Using inorganic 75Se in meat and human milk matrixes, an ammonium pyrrolidine dithiocarbamate-methyl isobutyl ketone-extraction system with added Cu(II) as a matrix modifier yielded the best extraction recoveries, 97 and 98%, respectively. Accuracy and precision of the method were tested using several official and unofficial biological standard materials. The mean accuracy was within 4% of the certified or best values of the standard materials and the day-to-day variation was 9%. The Se/Fe or Se/P interference limits proved to be low enough not to affect selenium determinations in practically all foods or diets. The practical detection limit of the method was 3 ng Se/g dry wt for 1.0 g dry wt samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Serum cholesterol and vitamins A and E in juvenile chronic arthritis.

Serum total cholesterol is decreased during acute infections and in adults with rheumatoid arthritis, probably partly because of enhanced lipid peroxidation. Oxidative stress also causes augmentation of inflammation and tissue damage in arthritic synovium. Therefore, concentrations of serum total cholesterol and the antioxidant vitamins A and E were studied in 125 children with juvenile chronic arthritis. Total serum cholesterol was significantly lower in the patients than in healthy children in most age groups and correlated with the markers of disease activity, haemoglobin and the erythrocyte sedimentation rate. In age- and sex-adjusted stepwise multiple linear regression, serum zinc had a significant predictive value for cholesterol. The vitamin A concentrations in the sera of the patients was virtually the same as in the healthy controls, though serum vitamin E concentrations were low (22.8 +/- 15.2 vs 30.5 +/- 4.3 mumol/l, p less than 0.001). The deficiency in vitamin E was not compensated for by another lipoperoxide antioxidant, glutathione peroxidase. Only serum cholesterol had an independent explanatory significance for vitamin E in multiple linear regression analysis (partial correlation 0.554, p less than 0.001). It is suggested that low vitamin E and impairment of the anti-oxidant protection further contribute to low serum cholesterol values in JCA.

Adolescent↗