Plasma concentrations of alpha-1-acid glycoprotein in preterm and term newborns: influence of mode of delivery and implications for plasma protein binding of local anaesthetics.

BACKGROUND: Alpha-1-acid glycoprotein (AAGP) is an acute-phase protein with high affinity for amide local anaesthetics (LAs), and a major determinant of free and potentially toxic concentrations of LAs in plasma. Neonates are known to have lower plasma concentrations of AAGP than adults, and are at risk of developing high free concentrations of LAs. Data regarding AAGP in newborns are so far sparse. The aim of this study was to determine plasma concentrations of AAGP after delivery of preterm and term infants, and to investigate correlations between AAGP and gestational age, birth weight, gender, and mode of delivery. METHODS: In this prospective observational study, blood was sampled from umbilical cords of 70 newborn infants born at gestational weeks 27-42 immediately after delivery. Blood samples were subsequently analysed for AAGP plasma concentrations with an immunoturbidimetric assay. RESULTS: We found higher concentrations of AAGP in infants born vaginally compared with those who were delivered by elective Caesarean section [median (inter-quartile range) 0.189 g litre-1 (0.142-0.263 g litre-1) vs 0.110 g litre-1 (0.094-0.157 g litre-1; P=0.0003)], respectively. There was a correlation between gestational age and AAGP concentrations (r=0.50; P=0.011), with significantly higher concentrations in the more mature infants. Gender and birth weight did not appear to influence the plasma concentrations of AAGP. CONCLUSIONS: Alpha-1-acid glycoprotein concentrations in newborns are influenced both by gestational age and mode of delivery. Thus, when dosing local anaesthetics in a parturient, these factors should be taken into account.

GH is a regulator of IGF2 promoter-specific transcription in human liver.

The regulation of the insulin-like growth factor-II gene (IGF2) is complex and involves the usage of four promoters resulting in different 5' untranslated regions, but with a common translated product. The IGF2 gene product is a mitogenic and survival factor that has been suggested to be important for a normal fetal development and cancer. In this paper we present evidence suggesting that the human IGF2 gene is regulated by GH, and that this regulation occurs in a promoter-specific way. Three lines of evidence support this finding. First, in vivo data from patients treated with GH (one injection or daily injections for 5 consecutive days) showed an increase in the IGF2 P2 promoter derived transcript after acute treatment, and of the P4 promoter transcript after short-term treatment while the P1 promoter derived transcript did not show any significant change. Secondly, isolated human liver cells treated with GH for 2 h displayed an upregulation of the P2 promoter derived transcript. Thirdly, employing transfection experiments in GH-receptor positive CHO cells with P2 and P4 promoter-luciferase constructs, an upregulation by GH was evident, while a P1 promoter construct was unresponsive. We suggest that GH may be a physiological regulator of IGF2 in humans.

Expression levels of insulin-like growth factor binding proteins and insulin receptor isoforms in hepatoblastomas.

Hepatoblastoma, a rare pediatric liver tumour, is a poorly understood disease. While expression studies for some members of the Insulin-like growth factor axis have been studied in hepatoblastoma, a systematic analysis of the IGF-axis has not been carried out. We have examined a series of hepatoblastomas with matched normal liver tissue for gene expression differences with emphasis on members of the insulin-like growth factor binding proteins. The expression profiles obtained reveal that the expression of these genes are altered in these tumors. The results indicate that the IGF-axis is seriously disturbed in the tumors.