Helicobacter pylori vacA s1a and s1b alleles from clinical isolates from different regions of Chile show a distinct geographic distribution.

AIM: To establish the most common vacA alleles in Helicobacter pylori (H pylori) strains isolated from Chilean patients and its relationship with gastritis and gastroduodenal ulcers. METHODS: Two hundred and forty five H pylori clinical isolates were obtained from 79 biopsies from Chilean infected patients suffering from gastrointestinal diseases. An average of 2-3 strains per patient was isolated and the vacA genotype was analyzed by PCR and 3% agarose electrophoresis. Some genotypes were checked by DNA sequencing. RESULTS: The most prevalent vacA genotype in Chilean patients was s1b m1 (76%), followed by s1a m1 (21%). In contrast, the s2 m2 genotype was scarcely represented (3%). The s1b m1 genotype was found most frequently linked to gastropathies (P<0.05) rather than ulcers. Ulcers were found more commonly in male and older patients. Curiously, patients living in cities located North and far South of Santiago, the capital and largest Chilean city, carried almost exclusively strains with the s1b m1 genotype. In contrast, patients from Santiago and cities located South of Santiago carried strains with either one or both s1a m1 and s1b m1 genotypes. Regarding the s2 m2 genotype, comparison with GenBank sequences revealed that Chilean s2 sequence was identical to those of Australian, American, and Colombian strains but quite different from those of Alaska and India. CONCLUSION: Differences in geographic distribution of the s and m vacA alleles in Chile and a relationship of s1b m1 genotype with gastritis were found. Sequence data in part support a hispanic origin for the vacA genotype. Asymmetric distribution of genotypes s1b m1 and s2 m2 recedes H Pylori strain distribution in Spain and Portugal.

Efficacy and safety of iodine in the postpartum period in an area of mild iodine deficiency.

BACKGROUND: Iodine deficiency (even moderate) plays a major role in pregnancy associated goiter development, which is only party reversible after pregnancy. The prevalence of post partum thyroiditis is reported to be slightly lower in areas of iodine deficiency. Thus iodine supplementation may be effective in decreasing pregnancy associated increase in thyroid volume, but enhances the risk of increasing the prevalence of thyroid dysfunction in the post partum period. Therefore, we evaluated the effect of iodine supplementation (with two different doses: 50 microg and 250 microg) on the prevalence of post partum thyroiditis and the decrease in thyroid volume up to 8 months post partum in an area of mild iodine deficiency. PATIENTS AND METHODS: Thyroid volume of 56 women was evaluated 5 days and 3 months after delivery (study I). In an intervention study (Study II) 70 women were randomized to receive 50 or 250 microg of potassium iodide for a period of 8 months post partum beginning five days after delivery. Thyroid volume, the echogenecity of the thyroid gland, thyroid hormone parameters (T4, T3, fT4, TSH) and thyroid antibodies (TPO and Tg-Ab) were measured 5 days, 3 and 8 months after delivery. RESULTS: A total number of 11 women developed postpartum thyroid dysfunction: 4 women developed manifest thyroid dysfunction (3 hyperthyroidism and 1 hypothyroidism) 3 months post partum. The remaining seven had subclinical hypo- or hyperthyroidism. All changes were clinically mild and transient as evidenced by normalization of thyroid hormone parameters on reexamination at 8 months. Among the eleven, 6 women in the 50 microg iodine group and 5 women of the 250 microg iodine group developed thyroid dysfunction, suggesting that the iodine dose did not affect post partum thyroiditis. The administration of only 50 microg iodine was associated with a significant fall of thyroid size already 3 months after delivery (25.4 +/- 1.5 ml (mean +/- sem) to 18.2 +/- 1.25 p <0.001). The application of 250 microg iodine was equally effective. 8 months post partum a slight but further decrease could be demonstrated. On the other hand, in study I no significant reduction in thyroid volume was observed in women receiving no supplementary iodine (thyroid volume at delivery 29 +/- 2.2 ml; at 3 months 27.5 +/- 3.0 ml. CONCLUSION: The administration of supplementary iodine (up to 250 microg) to an unselected population, residing in an area of mild iodine deficiency, in the post partum period is save as indicated by a prevalence of 5.7% manifest thyroid dysfunction. These changes are clinically mild and transient. Even the amount of 50 microg of iodine supplementation seems to by very efficient in reducing pregnancy associated increments in thyroid volume.