Development of a new blood test based on the helper lymphocytes Th-17 response for the diagnosis of allergies to dental metals: Preliminary results

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Thyroid volumes and urinary iodine in Swiss school children, 17 years after improved prophylaxis of iodine deficiency

Salt iodine content in Switzerland was raised from 7.5 to 15 mg per kg in 1980, and since then dietary iodine intake has been considered to be sufficient, even though a slight decrease due to imported food has recently been reported. The aim of this study was to establish normal values for thyroid volumes of school children who can be assumed to have had a sufficient iodine intake all their lifetime. Moreover, the present investigation was undertaken to verify that iodine sufficiency had been achieved equally in two regions each served by one of the two Swiss salt producers. Mean iodine concentration in urine spot samples from school children was 16.1 μg/dl, and it was identical in both the city of Lausanne (n=215) and the city of Solothurn (n=208). Thus it can be stated that in both cities (served by two different salt producers) iodine intake is equal and sufficient. Accordingly, thyroid volumes measured by ultrasound in school children aged 6 to 16 years were the same in both Lausanne (n=202) and Solothurn (n=207). Moreover, the age-adjusted median volumes at the 97th percentiles closely agree with and validate provisional international reference values recently proposed by the World Health Organisation and by the International Council for Control of Iodine Deficiency Disease.

Androgenic 17β-hydroxysteroid dehydrogenase activity of expressed rat type I 3β-hydroxysteroid dehydrogenase/Δ5-Δ4 isomerase

Transient expression in nonsteroidogenic mammalian cells of the rat wild type I and type II 3β-hydroxysteroid dehydrogenase/Δ5-Δ4-isomerase (3β- HSD) cDNAs shows that the encoded proteins, in addition to being able to catalyze the oxidation and isomerization of Δ5-3β-hydroxysteroid precursors into the corresponding Δ4-3-ketosteroids, interconvert 5α- dihydrotestosterone (DHT) and 5α-androstane-3β,17β-diol (3β-diol). When homogenate from cells transfected with a plasmid vector containing type I 3β-HSD is incubated in the presence of DHT using NAD+ as cofactor, a somewhat unexpected metabolite is formed, namely 5α-androstanedione (A- dione), thus indicating an intrinsic androgenic 17β-hydroxysteroid dehydrogenase (17β-HSD) activity of this 3β-HSD isoform. Although the relative Vmax of 17β-HSD activity is 14.9-fold lower than that of 3β-HSD activity, the Km value for the 17β-HSD activity of type I 3β-HSD is 7.97 μM, a value which is in the same range as the conversion of DHT into 3β- diol which shows a Km value of 4.02 μM. Interestingly, this 17β-HSD activity is highly predominant in unbroken cells in culture, thus supporting the physiological relevance of this 'secondary' activity. Such 17β-HSD activity is inhibited by the classical substrates of 3β-HSD, namely pregnenolone (PREG), dehydroepiandrosterone (DHEA), Δ5-androstene-3β,17β- diol (Δ5-diol), 5α-androstane-3β,17β-diol (3β-diol) and DHT, with IC50 values of 2.7, 1.0, 3.2, 6.2, and 6.3 μM, respectively. Although dual enzymatic activities have been previously reported for purified preparations of other steroidogenic enzymes, the present data demonstrate the multifunctional enzymatic activities associated with a recombinant oxidoreductase enzyme. In addition to its well known 3β-HSD activity, this enzyme possesses the ability to catalyze DHT into A-dione thus potentially controlling the level of the active androgen DHT in classical steroidogenic as well as peripheral intracrine tissues.