Analysis of a neutron-induced conversion electron spectrum of gadolinium.

A 100-nm-thick gadolinium layer deposited on a pixelated silicon sensor was activated in a neutron field to measure the internal conversion electron (ICE) spectrum generated by neutron capture products of 155Gd and 157Gd. The experiment was performed at the ISIS neutron and muon facility, using a bespoke version of the HEXITEC spectroscopic imaging camera. Signals originating from internal conversion electrons, Auger electrons, x rays and gamma rays up to 150 keV were identified. The ICE spectrum has an energy resolution of 1.8-1.9 keV at 72 keV and shows peaks from the K, L, M, N+ ICEs of the 79.51 keV and 88.967 keV 2+-0+ gamma transitions from the first excited states in 158Gd and 156Gd, respectively, as well as the K ICEs of the 4+-2+ transitions at 181.931 keV and 199.213 keV from the respective second excited states. Spectrum analysis was performed using a convolution of a Gaussian with exponential functions at the low and high energy side as the peak shaping function. Relative ICE intensities were derived from the fitted peak areas and compared with internal conversion coefficient (ICC) values calculated from the BrIcc database. Relative to the dominant L shell contribution, the K ICE intensity conforms to BrIcc and the M, N, O+ ICE intensities are somewhat higher than expected.

A reduction in sedentary behaviour in obese women during pregnancy reduces neonatal adiposity: the DALI randomised controlled trial.

AIMS/HYPOTHESIS: Offspring of obese women are at increased risk of features of the metabolic syndrome, including obesity and diabetes. Lifestyle intervention in pregnancy might reduce adverse effects of maternal obesity on neonatal adiposity. METHODS: In the Vitamin D And Lifestyle Intervention for Gestational Diabetes Mellitus (GDM) Prevention (DALI) lifestyle trial, 436 women with a BMI ≥29 kg/m2 were randomly assigned to counselling on healthy eating (HE), physical activity (PA) or HE&PA, or to usual care (UC). In secondary analyses of the lifestyle trial, intervention effects on neonatal outcomes (head, abdominal, arm and leg circumferences and skinfold thicknesses, estimated fat mass, fat percentage, fat-free mass and cord blood leptin) were assessed using multilevel regression analyses. Mediation of intervention effects by lifestyle and gestational weight gain was assessed. RESULTS: Outcomes were available from 334 neonates. A reduction in sum of skinfolds (-1.8 mm; 95% CI -3.5, -0.2; p = 0.03), fat mass (-63 g; 95% CI -124, -2; p = 0.04), fat percentage (-1.2%; 95% CI -2.4%, -0.04%; p = 0.04) and leptin (-3.80 µg/l; 95% CI -7.15, -0.45; p = 0.03) was found in the HE&PA group, and reduced leptin in female neonates in the PA group (-5.79 µg/l; 95% CI -11.43, -0.14; p = 0.05) compared with UC. Reduced sedentary time, but not gestational weight gain, mediated intervention effects on leptin in both the HE&PA and PA groups. CONCLUSIONS/INTERPRETATION: The HE&PA intervention resulted in reduced adiposity in neonates. Reduced sedentary time seemed to drive the intervention effect on cord blood leptin. Implications for future adiposity and diabetes risk of the offspring need to be elucidated. TRIAL REGISTRATION: ISRCTN70595832.

Environmental risk assessment of zinc in European freshwaters: a critical appraisal.

A risk assessment report (RAR) on zinc and zinc compounds has recently been prepared in the framework of the European Union (EU) Council Regulation 793/93/EEC on Existing Chemicals. The EU Scientific Committee on Human and Environmental Risks (SCHER) has, however, expressed some fundamental, science-based concerns about the approach followed and the conclusions. The main objective of the present study was to assess the potential environmental risks associated with current use patterns of Zn in nine EU river basins in Germany, France and Belgium, thereby using more advanced methodologies which are largely in line with the recommendations made by SCHER. This included (i) avoiding working with measured Zn concentrations from monitoring stations that were potentially influenced by point sources and/or historical contamination, (ii) the full bioavailability normalization of all chronic ecotoxicity data to river basin specific physico-chemistry using biotic ligand models (BLM), prior to deriving predicted no effect concentrations (PNEC) with the species sensitivity distribution (SSD) approach, and (iii) the use of a probabilistic framework for risk characterization. Further, a total risk approach instead of an added risk approach was used, and the PNEC was equated to the HC5-50 without an additional assessment factor. Based on monitoring data we estimated predicted environmental concentrations (PEC) for the different EU river basins between 1.3 and 14.6 microg dissolved Zn/L. PNEC values varied between 22.1 and 46.1 microg dissolved Zn/L. This resulted in deterministic risk characterization ratios (RCR) that were below 1 in all river basins, suggesting that there is no deterministic regional risk associated with current use patterns of Zn in these river basins. With the probabilistic approach we identified rather limited risks, i.e., between <0.4 and 18.3%. When the EU RAR approach was applied to the same monitoring datasets, deterministic risks were found in different river basins. A detailed analysis showed that this different deterministic conclusion of risk is mainly due to the fact that the EU RAR (i) uses an additional assessment factor of 2 to derive the PNEC and (ii) uses a more conservative approach for implementing bioavailability (BioF approach). We argue that the larger conservatism in the EU RAR mainly originates from decisions made to deal in a pragmatic way with (i) uncertainty related to the across-species extrapolation of BLMs and (ii) the relatively high sensitivity of some multi-species toxicity studies.

Established diet-induced obesity in female rats leads to offspring hyperphagia, adiposity and insulin resistance.

AIMS/HYPOTHESIS: Accumulating evidence suggests that maternal obesity may increase the risk of metabolic disease in the offspring. We investigated the effects of established maternal diet-induced obesity on male and female offspring appetite, glucose homeostasis and body composition in rats. METHODS: Female Wistar rats were fed either a standard chow (3% fat, 7% sugar [wt/wt]) or a palatable obesogenic diet (11% fat, 43% sugar [wt/wt]) for 8 weeks before mating and throughout pregnancy and lactation. Male and female offspring of control and obese dams were weaned on to standard chow and assessed until 12 months of age. RESULTS: At mating, obese dams were heavier than control with associated hyperglycaemia and hyperinsulinaemia. Male and female offspring of obese dams were hyperphagic (p < 0.0001) and heavier than control (p < 0.0001) until 12 months of age. NEFA were raised at 2 months but not at 12 months. At 3 months, OGTT showed more pronounced alteration of glucose homeostasis in male than in female offspring of obese animals. Euglycaemic-hyperinsulinaemic clamps performed at 8 to 9 months in female and 10 to 11 months in male offspring revealed insulin resistance in male offspring of obese dams (p < 0.05 compared with control). Body compositional analysis at 12 months also showed increased fat pad weights in male and female offspring of obese animals. CONCLUSIONS/INTERPRETATION: Diet-induced obesity in female rats leads to a state of insulin resistance in male offspring, associated with development of obesity and increased adiposity. An increase in food intake may play a role.

Copper and zinc water quality standards under the EU Water Framework Directive: the use of a tiered approach to estimate the levels of failure.

Environmental quality standards are an important tool for assessing the chemical quality of water bodies under the Water Framework Directive. However, there must be confidence in assessments of any failure to avoid disproportionate investment in unnecessary risk reduction. Metals present a number of unique challenges for environmental regulators in that they are naturally occurring and their ecotoxicology is driven, in part, by the physico-chemical conditions of the water body in which they are present. This paper describes the use of a tiered approach that could be adopted to assess compliance with any future environmental quality standards for metals under the Water Framework Directive. Through this approach, the use of background concentrations is considered and also bioavailability via the use of biotic ligand models. This assessment is based on an analysis of routine Environment Agency chemical monitoring data combined with biological indices to support results of the approach. Using copper and zinc as examples, it is shown that it is important to take account of background concentrations and the bioavailability of metals, otherwise the risk of impact from metals may be significantly overestimated. The approach presented here provides a methodology by which regulators and the regulated community may implement surface water standards for metals under the Water Framework Directive.

Aging does not aggravate the pregnancy-induced adaptations in glucose tolerance in rats.

Older age is an assumed risk factor for the development of gestational diabetes mellitus (GDM) in women. Here, we studied the effect of age and pregnancy on fat mass and glucose tolerance in rats. We performed intravenous glucose tolerance tests (IVGTTs) in 3- and 9-month-old rats, either nonpregnant or pregnant (day 20). In addition, we measured maternal fat mass, by dual-energy x-ray absorptiometry, and plasma leptin and lipid levels, as well as fetal parameters, on day 22. Nine-month-old rats had higher fat mass and plasma leptin, cholesterol, and triglyceride concentrations than 3-month-old rats. Glucose levels during the IVGTTs were elevated at several time points in 9-month-old rats, and the area under the curve (AUC) was increased. Pregnancy did not affect fat mass or the AUC for glucose during the IVGTT. The AUC for insulin during the IVGTTs was increased by age as well as pregnancy, but there was no interaction between the two by 2-factor analysis of variance. Reproductive performance was less optimal in 9-month-old rats, with a reduction of individual fetal and placental weight. In conclusion, 9-month-old rats exhibit a deterioration in glucose tolerance, possibly linked to the age-dependent increase in fat mass and leptin concentrations. Pregnancy also comprises certain adaptations in lipid and glucose metabolism, but because no interaction was found between both factors, the effect of pregnancy is not aggravated by aging. This may suggest than an increased gestational diabetes mellitus prevalence in older women can similarly be explained by age as such.

Animal evidence for the transgenerational development of diabetes mellitus.

The mammalian fetus develops inside the uterus of its mother and is completely dependent on the nutrients supplied by its mother. Disturbances in the maternal metabolism that alter this nutrient supply from mother to fetus can induce structural and functional adaptations during fetal development, with lasting consequences for growth and metabolism of the offspring throughout life. This effect has been investigated, by several research groups, in different experimental models where the maternal metabolism during pregnancy was experimentally manipulated (maternal diabetes and maternal malnutrition) and the effect on the offspring was investigated. The altered maternal/fetal metabolism appears to be associated with a diabetogenic effect in the adult offspring, including gestational diabetes. This diabetic pregnancy in the offspring again induces a diabetogenic effect into the next generation, via adaptations during fetal development. These experimental data in laboratory animals are confirmed by epidemiological studies on infants of mothers suffering from diabetes or malnutrition during pregnancy. It can be concluded that fetal development in an abnormal intra-uterine milieu can induce alterations in the fetal metabolism, with lasting consequences for the glucose tolerance of the offspring in adult life. The most marked effect is the development of gestational diabetes, thereby transmitting the diabetogenic tendency to the next generation again. The concept of fetal origin of adult diabetes therefore is of major significance for public health in the immediate and the far future.

[Scientific education in the training of specialists from the European perspective]. / Wetenschappelijke vorming in de opleiding van de specialisten in Europees perspectief.

An overview is given on the scientific education of the Trainees (Specialists in Training in Europe). European legislation is clear and insists on the scientific formation in the undergraduate as well as in the Postgraduate education. It is the task of the national (or regional) authorities to create possibilities for research during clinical training. In most of the national training programmes Research activities are included. Moreover in the European visiting system Research facilities are an important item. Examples are shown how the Royal College of Obstetricians and Gynaecologists (U.K.) and the European Board and College of Obstetrics and Gynaecology have implemented these Research activities in the training programme.

'Programming' of orexigenic and anorexigenic hypothalamic neurons in offspring of treated and untreated diabetic mother rats.

Exposure to maternal diabetes in utero (GD) may 'program' for obesity. Orexigenic neuropeptides, like neuropeptide Y (NPY) and agouti-related peptide (AGRP), and anorexigenic neuropeptides, like proopiomelanocortin (POMC) and alpha-melanocyte-stimulating hormone (MSH), are decisively involved in body weight regulation. We investigated consequences of GD and its treatment by pancreatic islet transplantation in rats for development of neuropeptidergic neurons in the arcuate hypothalamic nucleus (ARC) in weanling offspring. In GD, islet transplantation on d15 of pregnancy led to normalized blood glucose. Sham-transplanted GD mothers (TSGD) remained hyperglycemic. Twenty-one-day-old TSGD offspring developed hypothalamic 'malorganization'. Despite of normal leptin and insulin levels in TSGD offspring, increased immunopositivity of NPY and AGRP appeared. TSGD offspring showed unchanged POMC, but decreased MSH-immunopositivity. In conclusion, untreated diabetes in pregnant rats leads to 'malprogramming' of hypothalamic neuropeptidergic neurons in offspring, probably contributing to later development of overweight. These acquired alterations are preventable by treatment of maternal GD.

Diet-induced obesity in the rat: a model for gestational diabetes mellitus.

OBJECTIVES: Obesity is one of the most important risk factors for the development of gestational diabetes mellitus (GDM). However, in obese women, it is difficult to disentangle the genetic and environmental contributions. The aim of this study was to investigate whether diet-induced obesity results in GDM in rats with the same genetic background. STUDY DESIGN: Female Wistar rats were fed a cafeteria-style diet (CAF) or the standard control (C) diet from 70 days of age onward. After 4 weeks on the diets, subgroups of CAF and C rats were mated. In virgin and late-pregnant CAF and C rats, we determined body weight, body composition by dual-energy x-ray absorptiometry (DEXA), glucose tolerance by intravenous glucose tolerance test (IVGTT), and insulin sensitivity by hyperinsulinemic euglycemic clamp in nonanesthesized rats. Plasma leptin concentrations were also measured. RESULTS: Body weight increased after 4 weeks in virgin CAF rats (P<.0001) and exceeded that of C rats throughout pregnancy. This resulted exclusively from increased fat mass, as determined by DEXA, and was associated with a rise in plasma leptin concentrations in nonpregnant and pregnant (both P<.0001) CAF rats. During the IVGTT, nonpregnant CAF rats showed normal glucose levels but increased insulin levels compared with C rats (P<.05 for the area under the curve for insulin: AUC(insulin)). In pregnant CAF animals, glucose tolerance was clearly impaired (AUC(glucose): P<.001) with insulin also raised (AUC(insulin): P<.05). On day 22, fetal weight was comparable between C and CAF rats, but litter weight was higher in CAF rats (P<.05) owing to an increase in litter size. Hyperinsulinemic clamp studies revealed unequivocal insulin resistance in nonpregnant CAF rats, which was aggravated by pregnancy, the proportional effect of obesity being higher than that of pregnancy. CONCLUSION: Diet-induced obesity in rats is associated with glucose intolerance during pregnancy but not in the nonpregnant state. This is likely to result from the additive effects of obesity and pregnancy on insulin sensitivity. This obese rat model is an attractive model to study further the physiologic and molecular abnormalities in GDM.

Prevention by maternal pancreatic islet transplantation of hypothalamic malformation in offspring of diabetic mother rats is already detectable at weaning.

Exposure to gestational diabetes (GD) in rats leads to dysplasia of the ventromedial hypothalamic nucleus (VMN), decisively involved into the regulation of body weight and metabolism. Recently, we have shown here that VMN malformation is absent in adult offspring of GD mothers treated by pancreatic islet transplantation during gestation. We therefore now investigated whether VMN malformation and its prevention are already present at the early postnatal end of the critical hypothalamic differentiation period. Already at weaning, the total number of VMN neurons, the volume of the VMN relative to total brain volume, and the numerical density of neurons in the anterior subnucleus of the VMN were reduced in offspring of sham-transplanted mothers (all P<0.05), but did not differ between offspring of islet-transplanted mothers and controls. No morphometric alterations occurred in the paraventricular hypothalamic nucleus. In conclusion, prevention of VMN malformation in offspring of islet-transplanted diabetic mothers is a direct consequence of normalized maternal metabolism during critical perinatal development.

Fetal growth restriction and consequences for the offspring in animal models.

OBJECTIVE: In the present review we discuss rat models in which intra-uterine growth restriction is obtained through pharmacological (streptozotocin), dietary (global food restriction, low protein diet), or surgical (uterine artery ligation) manipulation of the maternal animal. METHODS: A MEDLINE search was performed on rat models of intrauterine growth restriction (IUGR), ie, streptozotocin, food restriction, low protein diet, or uterine artery ligation and pregnancy and fetal programming, long-term effects or adult offspring. RESULTS: We address the impact of the different maternal conditions for the fetal and neonatal development. The rat models we concentrate on were all associated with fetal hypoinsulinemia and intrauterine growth restriction. Both fetus and neonate adapt to the altered perinatal environment. Some of these adaptations may predispose the offspring to the development of insulin resistance, cardiovascular disease, obesity, and even overt diabetes in later life. CONCLUSION: The adaptations of the fetal metabolism to the altered intrauterine environment have consequences for the offspring, persisting into adulthood and into the next generation.

Intra-uterine transmission of disease.

Fetal development is dependent on maternal supply of fuels and building blocks. Disturbed maternal metabolism or inappropriate maternal nutrition confronts the fetus with an unfavourable intra-uterine milieu. Structural and functional adaptations occur during development and maturation of organs. Consequences of these fetal alterations persist postnatally and may result in metabolic alterations throughout life. Gestational diabetes can occur in these offspring and transmit the effect to the next generation. These alterations in fetal development can be associated with fetal macrosomia (maternal diabetes) or fetal growth-restriction (maternal/fetal malnutrition). The relation between birth weight and later metabolic disease therefore is U-shaped. Adult metabolic condition is thus to a considerable extent programmed in utero, fetal and neonatal weight being symptoms of disturbed fetal development. This concept of intra-uterine programming of disease is illustrated with a review of epidemiological human studies and experimental animal studies.

Is low-dose streptozotocin in rats an adequate model for gestational diabetes mellitus?

OBJECTIVE: To examine the use of streptozotocin (SZ) in rats as a model for gestational diabetes mellitus (GDM). METHODS: We studied various doses of SZ, either as a single administration (30, 35, 40, or 50 mg/kg, intraperitoneally) on day 1 of pregnancy or as 2 low doses (30 and 20 or 30 and 30 mg/kg) administered 2 days before mating and on day 1 of pregnancy. We examined the effect on maternal and fetal glucose and insulin concentrations and on fetal weight on day 20 of pregnancy. In a second series of experiments, we studied two groups (SZ 30/20 and SZ 35) with fetal hyperinsulinemia on day 20 of pregnancy. We performed an intravenous glucose tolerance test (IVGTT) on day 20, and in separate groups we reassessed fetal weight and insulin concentrations at term (day 22). RESULTS: There was considerable variability in glucose concentrations with most SZ doses. Lower doses of SZ (30, 30/20, and 35 mg/kg) did not significantly increase maternal and fetal glucose levels, in contrast to higher doses of SZ (30/30 and 50 mg/kg). Fetuses were smaller on day 20 with all doses except SZ 30 and SZ 30/20; fetal insulin concentrations were elevated with SZ 30, 30/20, and 35. The IVGTT showed glucose intolerance in SZ 35 and SZ 30/20, but the insulin response was unaffected in either group. Fetuses were smaller on day 22 in both these SZ groups, whereas fetal insulin levels at term were not different compared with controls. CONCLUSIONS: Low-dose SZ is not a good model for GDM because of the high variability in glucose levels, the normal insulin response to a glucose load, the absence of fetal macrosomia, and the inconsistent effect on fetal insulin concentrations.

Regulation of insulin-like growth factor-I and insulin-like growth factor binding protein-1 concentrations in preterm fetuses.

OBJECTIVE: Our purpose was to evaluate which factors regulate insulin-like growth factor-I and insulin-like growth factor binding protein-1 concentrations in preterm fetuses. STUDY DESIGN: We studied 76 singleton births between 25 and 36 weeks of gestation. Forty-nine pregnancies were complicated by hypertensive disease; 24 pregnancies were complicated by preterm labor or preterm rupture of membranes; and antenatal glucocorticoids were given in 49 pregnancies. Pathology reports showed infarct(s) or hematoma(s) in 31 of 69 placentas. We recorded blood gas values in umbilical artery and vein and measured glucose, C-peptide, and insulin-like growth factor-I and insulin-like growth factor binding protein-1 concentrations in umbilical vein. RESULTS: Birth weight correlated with umbilical vein insulin-like growth factor-I (r = 0.68, P <.0001) and inversely with insulin-like growth factor binding protein-1 (r = -0.26, P =.02). Babies with birth weight of 25th percentile. Two-factor analysis of variance showed that umbilical vein insulin-like growth factor-I was determined by gestational age (P =.0004) and birth weight percentile (P <.0001), whereas insulin-like growth factor binding protein-1 was not affected by gestational age. Umbilical vein C-peptide was highly correlated with insulin-like growth factor binding protein-1 (r = -0.55, P <.0001), but not insulin-like growth factor-I, levels. Blood gas values in umbilical artery and vein, particularly umbilical artery PO (2), were correlated with umbilical vein insulin-like growth factor-I and insulin-like growth factor binding protein-1 (r = 0.51 and -0.48, respectively; P <.0001); changes in insulin-like growth factor-I and insulin-like growth factor binding protein-1 occurred at umbilical artery PO (2) <14.8 mm Hg. Multiple regression analysis showed that umbilical vein insulin-like growth factor-I was predicted by umbilical artery PO (2), gestational age, and the presence of placental infarcts/hematomas (R (2) of model = 0.58, P <.0001), and umbilical vein insulin-like growth factor binding protein-1 by umbilical vein C-peptide, umbilical artery PO (2), and placental infarcts/hematomas (R (2) = 0.49, P <.0001). CONCLUSION: In the preterm fetus, circulating insulin-like growth factor-I is related to gestational age and the in utero growth potential, whereas insulin-like growth factor binding protein-1 is related only to the in utero growth potential. The PO (2) is a robust determinant of both insulin-like growth factor-I and insulin-like growth factor binding protein-1 levels; hypoxia may restrain fetal growth through its effects on the insulin-like growth factor/insulin-like growth factor binding protein axis. Insulin is a powerful determinant of insulin-like growth factor binding protein-1, but not insulin-like growth factor-I, concentrations in the preterm fetus.

Lifetime consequences of abnormal fetal pancreatic development.

There is ample evidence that an adverse intrauterine environment has harmful consequences for health in later life. Maternal diabetes and experimentally induced hyperglycaemia result in asymmetric overgrowth, which is associated with an increased insulin secretion and hyperplasia of the insulin-producing B-cells in the fetuses. In adult life, a reduced insulin secretion is found. In contrast, intrauterine growth restriction is associated with low insulin secretion and a delayed development of the insulin-producing B-cells. These perinatal alterations may induce a deficient adaptation of the endocrine pancreas and insulin resistance in later life. Intrauterine growth restriction in human pregnancy is mainly due to a reduced uteroplacental blood flow or to maternal undernutrition or malnutrition. However, intrauterine growth restriction can be present in severe diabetes complicated by vasculopathy and nephropathy. In animal models, intrauterine growth retardation can be obtained through pharmacological (streptozotocin), dietary (semi-starvation, low protein diet) or surgical (intrauterine artery ligation) manipulation of the maternal animal. The endocrine pancreas and more specifically the insulin-producing B-cells play an important role in the adaptation to an adverse intrauterine milieu and the consequences in later life. The long-term consequences of an unfavourable intrauterine environment are of major importance worldwide. Concerted efforts are needed to explore how these long-term effects can be prevented. This review will consist of two parts. In the first part, we discuss the long-term consequences in relation to the development of the fetal endocrine pancreas and fetal growth in the human; in the second part, we focus on animal models with disturbed fetal and pancreatic development and the consequences for later life.