Frans Andre Van Assche

Influence of the Vitamin D-binding Protein on the Serum Concentration of 1,25-Dihydroxyvitamin D3: SIGNIFICANCE OF THE FREE 1,25-DIHYDROXYVITAMIN D3 CONCENTRATION

The influence of the serum binding protein (DBP) for vitamin D and its metabolites on the concentration of its main ligands, 25-hydroxyvitamin D(3) (25-OHD(3)) and 1,25-dihydroxyvitamin D(3) (1,25-[OH](2)D(3)) was studied. The concentration of both 1,25-(OH)(2)D(3) and DBP in normal female subjects (45+/-14 ng/liter and 333+/-58 mg/liter, mean+/-SD, respectively; n = 58) increased during the intake of estro-progestogens (69+/-27 ng/liter and 488+/-90 mg/liter, respectively; n = 29), whereas the 25-OHD(3) concentration remained unchanged. A positive correlation was found between the concentrations of 1,25-(OH)(2)D(3) and DBP in these women. At the end of pregnancy, the total concentrations of 1,25-(OH)(2)D(3) (97+/-26 ng/liter, n = 40) and DBP (616+/-84 mg/liter) are both significantly higher than in nonpregnant females and paired cord serum samples (48+/-11 ng/liter and 266+/-41 mg/liter, respectively). A marked seasonal variation of 25-OHD(3) was observed in pregnant females and their infants, whereas in the same samples the concentrations of both DBP and 1,25-(OH)(2)D(3) remained constant throughout the year. The free 1,25-(OH)(2)D(3) index, calculated as the molar ratio of this steroid and DBP, remains normal in women taking estro-progestogens, however, and this might explain their normal intestinal calcium absorption despite a high total 1,25-(OH)(2)D(3) concentration. In pregnancy the free 1,25-(OH)(2)D(3) index remains normal up to 35 wk of gestation, but during the last weeks of gestation, the free 1,25-(OH)(2)D(3) index increases in both circulations. A highly significant correlation exists between the (total and free) 25-OHD(3) and 1,25-(OH)(2)D(3) concentrations in maternal and cord serum both at 35 and 40 wk of gestation.

Learning dashboards: an overview and future research opportunities

Abstract In this paper, we present work on learning analytics that aims to support learners and teachers through dashboard applications, ranging from small mobile applications to learnscapes on large public displays. Dashboards typically capture and visualize traces of learning activities, in order to promote awareness, reflection, and sense-making, and to enable learners to define goals and track progress toward these goals. Based on an analysis of our own work and a broad range of similar learning dashboards, we identify HCI issues for this exciting research area.

Misoprostol compared with methylergometrine for the prevention of postpartum haemorrhage: a double-blind randomised trial

Objective To compare the efficacy and side effects of misoprostol, compared with methylergometrine, for the prevention of postpartum haemorrhage.

PROLACTIN CONCENTRATION IN VAGINAL FLUID: A NEW METHOD FOR DIAGNOSING RUPTURED MEMBRANES

Prolactin concentrations were assayed in vaginal fluid, urine and plasma in 20 women between 38 and 41 weeks gestation. Plasma concentrations of 12·3 (7·3–20·8) mU/ml (n = 40) were found whereas urine concentrations were low or undetectable. Vaginal fluid concentrations were generally lower than 0·25 mU/ml but occasionally elevated up to 3 mU/ml in women with unruptured membranes. Half an hour after artificial rupture of the membranes, vaginal fluid prolactin concentrations were always higher than paired maternal plasma concentrations (p < 0·001). In women suspected of premature rupture of the membranes, prolactin concentrations in vaginal fluid were always higher than the plasma concentrations except in those in whom the clinical outcome showed that the membranes had not ruptured. A rapid prolactin radioimmunoassay is therefore recommended as a new clinical tool for the diagnosis or exclusion of prematurely ruptured membranes.

Fetal growth and developmental programming

Abstract The environment in utero and in early neonatal life may induce a permanent response in the fetus and the newborn, leading to enhanced susceptibility to later diseases. This review concentrates on the role and mechanisms of events during the antenatal and immediate postnatal period resulting in later life diseases, concentrating on abnormal growth patterns of the fetus. Fetal overgrowth is related to exposure to a diabetic intra uterine environment, increasing the vulnerability to transgenerational obesity and hence an increased sensitivity to more diabetic mothers. This effect has been supported by animal data. Fetal growth restriction is complex due to malnutrition in utero, catch up growth due to a high caloric intake and low physical activity in later life. Metabolic changes and a transgenerational effect of intra uterine malnutrition has been supported by animal data. In recent years the discovery of alterations of the genome due to different influences during embryonic life, called epigenetics, has led to the phenomenon of fetal programming resulting in changing transgenerational metabolic effects.

Reduced adaptation of the pancreatic B cells during pregnancy is the major causal factor for gestational diabetes: Current knowledge and metabolic effects on the offspring

This commentary summarizes current knowledge on the pathophysiology of gestational diabetes, focusing on the role of the endocrine pancreas and the β‐cells, their adaptation in normal pregnancy, and recent insights in the molecular basis for deficient adaptation in diabetes occurring during pregnancy. Additionally, the effects of disturbed maternal glucose metabolism during pregnancy on the glucose metabolism of the offspring are discussed.

Tobacco smoking and the uterine cervix: cotinine in blood, urine and cervical fluid

Cotinine levels in blood, urine and cervical fluid of smokers and nonsmokers were analyzed by capillary-column gas chromatography. The sensitivity of this method appeared to be 100%. The specificity was lower (87.5% in blood, 25% in urine and 75% in cervical fluid). Nonsmokers exposed to smoke by others had low but detectable cotinine levels in the three body fluids. The highest cotinine levels in cervical fluid were detected during the proliferative phase of the cycle. Cotinine levels in cervical fluid and blood correlated well, but the correlation was less during the proliferation phase. Cotinine measurement in cervical fluid proves to be a reliable method to quantify exposure to tobacco smoke, even when induced by others.

A framework for quality of learning resources

To better understand the complex question of quality of web-based learning resources it is beneficial to look at the different processes during the life of a learning resource; what are the aspects of quality that are related to the creation of material, its discovery and eventually its use and re-use for learning purposes. Obviously this involves different roles which should be distinguished as quality aspects are different for those roles. This chapter therefore looks at the different processes related to learning resources and the roles involved in these processes with the aim to understand the quality aspects of the processes as well as the roles, which have responsibilities regarding the quality for these processes.

Metabolic alterations in adulthood after intrauterine development in mothers with mild diabetes.

We studied the long-term effects of maternal diabetes mellitus on the offspring of experimentally induced diabetic Wistar rats. When stressed by an intravenous glucose load, the adult female offspring had impaired glucose tolerance and developed gestational diabetes mellitus when pregnant. Our results show that even mild diabetes mellitus induces an abnormal intrauterine milieu that causes morphological and functional changes in fetal development with consequences for later life.

Vitamin D Deficiency in Guinea Pigs: Exacerbation of Bone Phenotype During Pregnancy and Disturbed Fetal Mineralization, with Recovery by 1,25(OH)2D3 Infusion or Dietary Calcium-Phosphate Supplementation

Vitamin D (D) deficiency during human pregnancy appears to disturb fetal growth and mineralization, but fetal development is normal in D-deficient rats and vitamin D receptor gene-ablated mice. We used the guinea pig model to investigate maternal and fetal effects of D deficiency. Pregnant (Pr) and nonpregnant (NPr) animals were fed a D-replete (+D) or D-deficient diet (?D) for 8 weeks. We further studied whether the effects of a ?D diet are reversed by continuous 1,25(OH)2D3 infusion (?D+1,25) and/or by a lactose-, Ca- and P-enriched D-deficient diet (?D+Ca/P). Bone analyses included histomorphometry of the proximal tibiae, dual-energy X-ray absorptiometry (DXA), and quantitative computed tomography (QCT) of the femora. Depletion of 25(OH)D3 and 1,25(OH)2D3 levels and the D-deficiency syndrome were more severe in pregnant animals. Indeed, Pr/?D but not NPr/?D guinea pigs were hypophosphatemic, and showed robust increases in growth plate width and osteoid surface and thickness; in addition, bone mineral density on DXA was lower in Pr/?D animals only, which was exclusively in cortical bone on QCT. Bone phenotype was partly normalized in Pr/?D+1,25 and Pr/?D+Ca/P animals. Compared with +D fetuses, ?D fetuses had very low or undetectable 25(OH)D3 and 1,25(OH)2D3, were hypercalcemic and hypophosphatemic, and had lower osteocalcin levels. In addition, body weight and total body bone mineral content were 10–15% lower; histomorphometry showed hypertrophic chondrocyte zone expansion and hyperosteoidosis. 1,25(OH)2D3 levels were restored in ?D+1,25 fetuses, and the phenotype was partially corrected. Similarly, the fetal +D phenotype was rescued in large part in ?D+Ca/P fetuses, despite undetectable circulating 25(OH)D3 and 1,25(OH)2D3. We conclude that pregnancy markedly exacerbates D deficiency, and that augmenting Ca and P intake overrides the deleterious effects of D deficiency on fetal development.