Levels of ochratoxin A in blood from Norwegian and Swedish blood donors and their possible correlation with food consumption.

Blood levels of ochratoxin A were determined in 406 Scandinavian blood donors (206 from Oslo, Norway, and 200 from Visby on the island of Gotland, Sweden), using an HPLC method. In connection with the blood collection, the subjects were asked to fill in a food questionnaire to obtain individual dietary information relevant to ochratoxin A exposure. The mean plasma level of ochratoxin A was 0.18 ng/ml in Oslo and slightly higher, 0.21 ng/ml (P=0.046) in Visby. There was no correlation between plasma levels of ochratoxin A and the estimated total dietary intake of ochratoxin A based on consumption data and levels in food (retrieved from the literature), neither was the plasma level of ochratoxin A correlated with the total amount of food consumed. However, consumption of several foods, including cereal products, wine, beer and pork, were to some minor degree related to high plasma levels of ochratoxin A. The strongest correlations (correlation coefficient r>0.4; P<0.001) were observed for women in relation to the consumption of beer or medium brown bread. Correlation analysis of combinations of two or more food categories did not result in any statistically significant correlation.

Simple and accurate method for determination of ethylene chlorohydrin in dried spices and condiments.

A simple and accurate method is described for the determination of ethylene chlorohydrin (ECH) by using capillary gas chromatography (GC) and flame ionization detection. Acetonitrile-methanol was chosen as the extraction solvent in preference to other solvents because its use reduced the number of compounds detected by the GC system, thus enabling easier identification and quantitation of ECH. The coefficient of variation for the method is 2.7% at 5 ppm, and recovery is good, even for the standard addition of 1 ppm. Fifteen different spices and condiments were analyzed using this method; 20% were identified as positive for ECH. The method also identifies the related compound ethylene bromohydrin (EBH).

A single site serum ferritin immunoradiometric assay. A comparison between serum and liver ferritin standards and two antibody preparations.

A single site immunoradiometric assay (1S-IRMA) for serum ferritin was developed to investigate some standardization problems in the assay of ferritin. In comparison to this 1S-IRMA, a 2-site solid phase IRMA gave lower answers of serum ferritin in the normal reference range, as well as in serum from idiopathic hemochromatosis patients. Purified serum ferritin or liver ferritin gave different standard curves in this new immunoassay system and the differences obtained were further dependent on the antibody preparation employed. The different isoferritin profiles obtained, dependent on the antibody preparation employed for ferritin purification, indicate a different antibody specificity for different ferritin subunits. Serum ferritin purified from different serum pools from healthy persons showed similar isoferritin profiles and immunoassay reactivities.

Triiodothyronine (T3) binding to immunoglobulin G subclasses in a slightly hypothyroid woman.

A 44-year-old woman, with an earlier history of myxoedema, had stopped taking thyroxine and was found to have both a slightly elevated basal TSH level and an increased TSH response after thyroliberin stimulation. The T4 value was low borderline, and using a radioimmunoassay that separated free and antibody-bound hormone by polyethylene glycol precipitation, the T3 value was found to be less than zero. This last finding was explained by the existence of T3 antibodies in the patient's serum. The antibodies, being of the IgG class, did not bind T4, thyroglobulin or cytoplasmic thyroid antigen. The subclass IgG2, and to a lesser extent IgG1, IgG3 and IgG4, did bind T3. A Scatchard plot gave an antibody avidity constant of 4.28 x 10(8) l/mol and a binding site concentration of 3.8 x 10(-9) mol/l. Radioimmunoassay of total T3, after extraction with ethanol gave a high value. The concentration of free T3 was, however, just above the lower reference limit.

Serum ferritin in young men during prolonged heavy physical exercise.

The level of serum ferritin were investigated in 44 young men during strenuous ranger training courses lasting 4-5 d. These cadets were continuously subjected to heavy physical activities, almost without sleep and with a caloric deficit amounting to 29000-39000 kj per 24 h. Ferritin concentrations were consistently increased during the courses, and were still significantly elevated 2 d after the end of the courses. The increase of ferritin appeared to be correlated with decreased Hb values and increased total bilirubin. The results indicate that iron released from disintegrated erythrocytes probably causes increased ferritin synthesis in the reticuloendothelic cells and a subsequent release of ferritin in blood.

Radioimmunological assays for triiodothyronine(T3) or thyroxine(T4) in sera containing antibodies against the hormones.

For serum samples containing antibodies in vivo against triiodothyronine or thyroxine, the radioimmunoassays in use may give highly erroneous results. We wanted to compare the effects of two different radioimmunoassay systems on such sera, and to develop a suitable extraction procedure for use before such assays. Very different results were obtained with the use of single antibody or double antibody techniques on unextracted sera. The highest recoveries of total T3 and T4 from sera were found with two successive ethanol extractions.