RESUMEN
AIM: To characterise parathyroid hormone (PTH) concentrations in infants at high risk for metabolic bone disease, in order to assist clinical decisions around the use of PTH for screening. METHODS: Infants born under 28 weeks' postmenstrual age or with birthweight under 1.5 kg in a tertiary neonatal unit in the UK were included. Clinical guidance was to assess PTH concentration in the first 3 weeks after birth. Clinical information was extracted from prospective records. RESULTS: Sixty-four infants had mean birth gestation of 26 weeks and birthweight of 882 g. Median PTH (sent on median day 18 of life) was 9.2 pmol/L (interquartile range 5.3-17 pmol/L). Sixty-seven per cent of infants had a PTH greater than 7 pmol/L. For 22% of the infants, raised PTH was not accompanied by abnormal phosphate or alkaline phosphatase. Eighty-nine per cent of infants tested were insufficient or deficient for 25-hydroxyvitamin D. CONCLUSIONS: Universal screening highlights the high frequency of high PTH in this high-risk population, implying a need for calcium supplementation. A considerable number of infants would not be identified as showing potential signs of metabolic bone disease if the assessment excludes the use of PTH. The high level of 25-hydroxyvitamin D deficiency may be a confounder.
RESUMEN
AN1 is a regulatory gene that promotes anthocyanin biosynthesis in potato tubers and encodes a R2R3 MYB transcription factor. However, no clear evidence implicates AN1 in anthocyanin production in leaves, where these pigments might enhance environmental stress tolerance. In our study we found that AN1 displays intraspecific sequence variability in both coding/non-coding regions and in the promoter, and that its expression is associated with high anthocyanin content in leaves of commercial potatoes. Expression analysis provided evidence that leaf pigmentation is associated to AN1 expression and that StJAF13 acts as putative AN1 co-regulator for anthocyanin gene expression in leaves of the red leaf variety 'Magenta Love,' while a concomitant expression of StbHLH1 may contribute to anthocyanin accumulation in leaves of 'Double Fun.' Yeast two-hybrid experiments confirmed that AN1 interacts with StbHLH1 and StJAF13 and the latter interaction was verified and localized in the cell nucleus by bimolecular fluorescence complementation assays. In addition, transgenic tobacco (Nicotiana tabacum) overexpressing a combination of either AN1 with StJAF13 or AN1 with StbHLH1 showed deeper purple pigmentation with respect to AN1 alone. This further confirmed AN1/StJAF13 and AN1/StbHLH1 interactions. Our findings demonstrate that the classical loci identified for potato leaf anthocyanin accumulation correspond to AN1 and may represent an important step to expand our knowledge on the molecular mechanisms underlying anthocyanin biosynthesis in different plant tissues.