Susceptibility of Candida albicans to peroxidase-catalyzed oxidation products of thiocyanate, iodide and bromide.

The susceptibility of Candida albicans (ATCC 10231 and wild strains) to hypo(pseudo)halous ions (OSCN-, OBr-, OI-) produced by the lactoperoxidase system was tested. Six strains of Candida albicans were isolated from swabs taken from the mouths of children with orthodontic appliances and selected on Sabouraud-Chloramphenicol-Actidione agar plates. The survival rate of Candida blastospores after a 30 min exposure to lactoperoxidase system ranged from 79 to 105% in the presence of 615 microM thiocyanate, from 56 to 88% in the presence of 345 microM bromide and from 0 to 4% in the presence of 250 microM iodide. Results showed that only OI- could exert a strong inhibiting effect in vitro on Candida albicans at physiological concentrations. Nevertheless, the activity of the hypoiodite generating system in saliva was found to be under the control of thiocyanate concentration.

Superiority of thyrotropin to thyroxine as a tool in the screening for congenital hypothyroidism by the filter paper spot technique.

The effects of storage on the assessment of thyroxine (T4) and thyrotropin (TSH) were evaluated in blood spots collected on filter paper according to the methods commonly used in screening for congenital hypothyroidism. Comparisons were made with serum values obtained simultaneously in the same subjects. In samples stored at room temperature a clear-cut decrease in T4 was observed after 24 hours while TSH was stable for at least 15 days. Spot samples collected in an area of severe endemic goiter in Africa and analyzed in Brussels displayed a systematic decrease in T4 (up to 133 nmol/l) while TSH was fairly stable. Spot samples collected in Belgium were stored at -18 degrees C and were reassayed after 1 year; they did not show any significant change in TSH but a systematic decrease in T4. We conclude that spot TSH is the tool of choice in screening for congenital hypothyroidism particularly in developing countries and that spot T4 should not be used for field studies or under any circumstances in which assays cannot be performed very soon after blood collection.