Maternal obesity and pregnancy outcome: a study of 287,213 pregnancies in London

OBJECTIVE

To examine the maternal and foetal risks of adverse pregnancy outcome in relation to maternal obesity, expressed as body mass index (BMI, kg/m(2)) in a large unselected geographical population.

DESIGN

Retrospective analysis of data from a validated maternity database system which includes all but one of the maternity units in the North West Thames Region. A comparison of pregnancy outcomes was made on the basis of maternal BMI at booking.

SUBJECTS

A total of 287,213 completed singleton pregnancies were studied including 176,923 (61.6%) normal weight (BMI 20--24.9), 79 014 (27.5%) moderately obese (BMI 25--29.9) and 31,276 (10.9%) very obese (BMI> or =30) women.

MEASUREMENTS

Ante-natal complications, intervention in labour, maternal morbidity and neonatal outcome were examined and data presented as raw frequencies and adjusted odds ratios with 99% confidence intervals following logistic regression analysis to account for confounding variables.

RESULTS

Compared to women with normal BMI, the following outcomes were significantly more common in obese pregnant women (odds ratio (99% confidence interval) for BMI 25--30 and BMI> or =30 respectively): gestational diabetes mellitus (1.68 (1.53--1.84), 3.6 (3.25--3.98)); proteinuric pre-eclampsia (1.44 (1.28--1.62), 2.14 (1.85--2.47)); induction of labour (2.14 (1.85--2.47), 1.70 (1.64--1.76)); delivery by emergency caesarian section (1.30 (1.25--1.34), 1.83 (1.74--1.93)); postpartum haemorrhage (1.16 (1.12--1.21), 1.39 (1.32--1.46)); genital tract infection (1.24 (1.09--1.41), 1.30 (1.07--1.56)); urinary tract infection (1.17 (1.04-1.33), 1.39 (1.18--1.63)); wound infection (1.27 (1.09--1.48), 2.24 (1.91--2.64)); birthweight above the 90th centile (1.57 (1.50--1.64), 2.36 (2.23--2.50)), and intrauterine death (1.10 (0.94--1.28), 1.40 (1.14--1.71)). However, delivery before 32 weeks' gestation (0.73 (0.65--0.82), 0.81 (0.69--0.95)) and breastfeeding at discharge (0.86 (0.84--0.88), 0.58 (0.56--0.60)) were significantly less likely in the overweight groups. In all cases, increasing maternal BMI was associated with increased magnitude of risk.

CONCLUSION

Maternal obesity carries significant risks for the mother and foetus. The risk increases with the degree of obesity and persists after accounting for other confounding demographic factors. The basis of many of the complications is likely to be related to the altered metabolic state associated with morbid obesity.

The transcriptional landscape of polyploid wheat

The coordinated expression of highly related homoeologous genes in polyploid species underlies the phenotypes of many of the world's major crops. Here we combine extensive gene expression datasets to produce a comprehensive, genome-wide analysis of homoeolog expression patterns in hexaploid bread wheat. Bias in homoeolog expression varies between tissues, with ~30% of wheat homoeologs showing nonbalanced expression. We found expression asymmetries along wheat chromosomes, with homoeologs showing the largest inter-tissue, inter-cultivar, and coding sequence variation, most often located in high-recombination distal ends of chromosomes. These transcriptionally dynamic genes potentially represent the first steps toward neo- or subfunctionalization of wheat homoeologs. Coexpression networks reveal extensive coordination of homoeologs throughout development and, alongside a detailed expression atlas, provide a framework to target candidate genes underpinning agronomic traits in wheat.

Putting the ‘landscape’ in landscape genetics

Landscape genetics has emerged as a new research area that integrates population genetics, landscape ecology and spatial statistics. Researchers in this field can combine the high resolution of genetic markers with spatial data and a variety of statistical methods to evaluate the role that landscape variables play in shaping genetic diversity and population structure. While interest in this research area is growing rapidly, our ability to fully utilize landscape data, test explicit hypotheses and truly integrate these diverse disciplines has lagged behind. Part of the current challenge in the development of the field of landscape genetics is bridging the communication and knowledge gap between these highly specific and technical disciplines. The goal of this review is to help bridge this gap by exposing geneticists to terminology, sampling methods and analysis techniques widely used in landscape ecology and spatial statistics but rarely addressed in the genetics literature. We offer a definition for the term "landscape genetics", provide an overview of the landscape genetics literature, give guidelines for appropriate sampling design and useful analysis techniques, and discuss future directions in the field. We hope, this review will stimulate increased dialog and enhance interdisciplinary collaborations advancing this exciting new field.

Maternal nutrition in early and late pregnancy in relation to placental and fetal growth

OBJECTIVE

To assess how nutrient intakes of mothers in early and late pregnancy influence placental and fetal growth.

DESIGN

Prospective observational study.

SETTING

Princess Anne Maternity Hospital, Southampton.

SUBJECTS

538 mothers who delivered at term.

MAIN OUTCOME MEASURES

Placental and birth weights adjusted for the infant's sex and duration of gestation.

RESULTS

Mothers who had high carbohydrate intakes in early pregnancy had babies with lower placental and birth weights. Low maternal intakes of dairy and meat protein in late pregnancy were also associated with lower placental and birth weights. Placental weight fell by 49 g(95% confidence interval 16 g to 81 g; P=0.002) for each log g increase in intake of carbohydrate in early pregnancy and by 1.4 g (0.4 g to 2.4 g; P=0.005) for each g decrease in intake of dairy protein in late pregnancy. Birth weight fell by 165 g (49 g to 282 g; P=0.005) for each log g increase in carbohydrate intake in early pregnancy and by 3.1 g (0.3 g to 6.0 g; P=0.03) for each g decrease in meat protein intake in late pregnancy. These associations were independent of the mother's height and body mass index and of strong relations between the mother's birth weight and the placental and birth weights of her offspring.

CONCLUSION

These findings suggest that a high carbohydrate intake in early pregnancy suppresses placental growth, especially if combined with a low dairy protein intake in late pregnancy. Such an effect could have long term consequences for the offspring's risk of cardiovascular disease.

Follicle-stimulating hormone levels on cycle day 3 are predictive of in vitro fertilization outcome

Cycle day 3 basal levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E2) were measured in 441 patients in 758 consecutive cycles to determine their predictive value for stimulation quality and pregnancy rates in vitro fertilization (IVF). Patients with low basal FSH levels (less than 15 mIU/ml) had higher pregnancy rates per attempt than those with moderate levels (15 to 24.9 mIU/ml), both of which were higher than those with high FSH levels (greater than 25 mIU/ml). Basal LH and E2 values did not improve the predictive value beyond that provided by FSH. Ongoing pregnancy rates per attempt in the low, moderate, and high FSH groups were 17.0%, 9.3%, and 3.6%, respectively (P less than 0.01). The three groups differed significantly in the percentage of patients having two ovaries, the mean number of follicles aspirated per retrieval, the mean number of preovulatory oocytes obtained, and peak E2 values (P less than 0.01). Cycle day 3 FSH levels are predictive of pregnancy outcome and stimulation characteristics in IVF, and may be useful in counseling patients.

Overexpression of petunia chalcone isomerase in tomato results in fruit containing increased levels of flavonols

Tomatoes are an excellent source of the carotenoid lycopene, a compound that is thought to be protective against prostate cancer. They also contain small amounts of flavonoids in their peel ( approximately 5-10 mg/kg fresh weight), mainly naringenin chalcone and the flavonol rutin, a quercetin glycoside. Flavonols are very potent antioxidants, and an increasing body of epidemiological data suggests that high flavonoid intake is correlated with a decreased risk for cardiovascular disease. We have upregulated flavonol biosynthesis in the tomato in order to generate fruit with increased antioxidant capacity and a wider range of potential health benefit properties. This involved transformation of tomato with the Petunia chi-a gene encoding chalcone isomerase. Resulting transgenic tomato lines produced an increase of up to 78 fold in fruit peel flavonols, mainly due to an accumulation of rutin. No gross phenotypical differences were observed between high-flavonol transgenic and control lines. The phenotype segregated with the transgene and demonstrated a stable inheritance pattern over four subsequent generations tested thus far. Whole-fruit flavonol levels in the best of these lines are similar to those found in onions, a crop with naturally high levels of flavonol compounds. Processing of high-flavonol tomatoes demonstrated that 65% of flavonols present in the fresh fruit were retained in the processed paste, supporting their potential as raw materials for tomato-based functional food products.

The risks associated with pregnancy in women aged 35 years or older

The obstetric risks of adverse outcome during pregnancy in women aged > or =35 years were quantified using a retrospective analysis of data from 385 120 singleton pregnancies in the North West Thames Region, UK, between 1988 and 1997. A comparison of pregnancy outcome was made on the basis of maternal age at delivery: 18-34 years (n = 336 462), 35-40 years (n = 41 327) and women aged > 40 years (n = 7331). Women aged <18 years (n = 5246) were excluded from the study. Data are presented as percentages of 18-34 year old women, 35-40 year old and > 40 year old women, with adjusted odds ratios (OR) according to age group. Pregnant women aged 35-40 years were at increased risk of: gestational diabetes, OR = 2.63 [99% confidence interval (CI) 2.40-2.89]; placenta praevia = 1.93 (1.58-2.35); breech presentation = 1.37 (1.28-1.47); operative vaginal delivery = 1.5 (1.43-1.57); elective Caesarean section = 1.77 (1.68-1.87); emergency Caesarean section = 1.59 (1.52-1.67); postpartum haemorrhage = 1.14 (1.09-1.19); delivery before 32 weeks gestation = 1.41 (1.24-1.61); birthweight below the 5th centile = 1.28 (1.20-1. 36); and stillbirth = 1.41 (1.17-1.70). Women aged >40 years had higher OR for the same risks. Pregnant women aged >/=35 years are at increased risk of complications in pregnancy compared with younger women.

Glial cell line-derived neurotrophic factor-dependent RET activation can be mediated by two different cell-surface accessory proteins

Glial cell line-derived neurotrophic factor (GDNF)-dependent activation of the tyrosine kinase receptor RET is necessary for kidney and enteric neuron development, and mutations in RET are associated with human diseases. Activation of RET by GDNF has been shown to require an accessory component, GDNFR-alpha (RETL1). We report the isolation and characterization of rat and human cDNAs for a novel cell-surface associated accessory protein, RETL2, that shares 49% identity with RETL1. Both RETL1 and RETL2 can mediate GDNF dependent phosphorylation of RET, but they exhibit different patterns of expression in fetal and adult tissues. The most striking differences in expression observed were in the adult central and peripheral nervous systems. In addition, the mechanisms by which the two accessory proteins facilitate the activation of RET by GDNF are quite distinct. In vitro binding experiments with soluble forms of RET, RETL1 and RETL2 demonstrate that while RETL1 binds GDNF tightly to form a membrane-associated complex which can then interact with RET, RETL2 only forms a high affinity complex with GDNF in the presence of RET. This strong RET dependence of the binding of RETL2 to GDNF was confirmed by FACS analysis on RETL1 and RETL2 expressing cells. Together with the recent discovery of a GDNF related protein, neurturin, these data raise the possibility that RETL1 and RETL2 have distinctive roles during development and in the nervous system of the adult. RETL1 and RETL2 represent new candidate susceptibility genes and/or modifier loci for RET-associated diseases.

The effects of severe behavior problems in children on the teaching behavior of adults

Applied behavior analysts have focused on how adults can influence the problem behavior of children using a variety of behavior modification strategies. A related question, virtually unexplored, is how the behavior problems of children influence adults. This child-effects concept was explored empirically in a study involving 12 adults who were asked to teach four pairs of children in which one member of the pair exhibited problem behavior and the other typically did not. Results demonstrated that problem children displayed tantrums, aggression, and self-injury contingent on adult instructional attempts but not at other times, whereas nonproblem children showed little or no problem behavior at any time. Importantly, from a child-effects perspective, adults engaged in teaching activities with nonproblem children more often than with problem children. Also, when an adult worked with a problem child, the breadth of instruction was more limited and typically involved those tasks associated with lower rates of behavior problems. The implications of these results are discussed with respect to theories of escape behavior, current assessment practices, and intervention issues related to maintenance. The existence of child effects suggests that problem behavior may be better understood when it is conceptualized as involving a process of reciprocal influence between adult and child.

Current concepts on adhesion to dentin

This review examines fundamental concepts in bonding to dentin. Emphasis is placed on the structure and permeability characteristics of dentin and how they may influence its interaction with adhesive resin. Several new techniques to examine the interfaces between resin and dentin are reviewed along with some of their limitations. The advantages and disadvantages of acid etchants/conditioners vs. self-etching conditioners/primers are discussed. The problems of matching the surface tension of resin-bonding systems to the surface energy of the substrate are reviewed in terms of wetting the various components of dentin. The problems associated with matching the permeability of intertubular dentin to the diffusibility of bonding reagents are explored. Speculation is advanced on how to ensure polymerization and wetting of dentinal collagen. Theoretical problems associated with dentin bonding and with bond testing are reviewed to encourage future research in this rapidly developing area.

Tailored prophylaxis in severe hemophilia A: interim results from the first 5 years of the Canadian Hemophilia Primary Prophylaxis Study

BACKGROUND

Prophylactic treatment for severe hemophilia A is likely to be more effective than treatment when bleeding occurs, however, prophylaxis is costly. We studied an inception cohort of 25 boys using a tailored prophylaxis approach to see if clotting factor use could be reduced with acceptable outcomes.

METHODS

Ten Canadian centers enrolled subjects in this 5-year study. Children were followed every 3 months at a comprehensive care hemophilia clinic. They were initially treated with once-weekly clotting factor; the frequency was escalated in a stepwise fashion if unacceptable bleeding occurred. Bleeding frequency, target joint development, physiotherapy and radiographic outcomes, as well as resource utilization, were determined prospectively.

RESULTS

The median follow-up time was 4.1 years (total 96.9 person-years). The median time to escalate to twice-weekly therapy was 3.42 years (lower 95% confidence limit 2.05 years). Nine subjects developed target joints at a rate of 0.09 per person-year. There was an average of 1.2 joint bleeds per person-year. The cohort consumed on average 3656 IU kg(-1)year(-1) of factor (F) VIII. Ten subjects required central venous catheters (three while on study); no complications of these devices were seen. One subject developed a transient FVIII inhibitor. End-of-study joint examination scores--both clinically and radiographically--were normal or near-normal.

CONCLUSIONS

Most boys with severe hemophilia A will probably have little bleeding and good joint function with tailored prophylaxis, while infusing less FVIII than usually required for traditional prophylaxis.

Rearrangement of nitrogen fixation genes during heterocyst differentiation in the cyanobacterium Anabaena

Nitrogen fixation by the cyanobacterium Anabaena is carried out in heterocysts, specialized, non-dividing cells which differentiate under conditions of ammonia or nitrate deprivation. In Anabaena, heterocyst differentiation is accompanied by rearrangement of some nitrogen fixation genes. A site-specific recombination between an 11 base-pair direct repeat sequence flanking the nifK and nifD genes removes 11 kilobases of intervening DNA, resulting in juxtaposition of the two genes and an alteration of the nifD protein-coding sequence.

Review article: Obesity in pregnancy

Overweight and obesity are common findings in women of reproductive age in the UK; as 32% of 35- to 64-year-old women are overweight and 21% obese. Obesity causes major changes in many features of maternal intermediary metabolism. Insulin resistance appears to be central to these changes and may also be involved in increased energy accumulation by the fetus. Maternal obesity is associated with many risks to the pregnancy, with increased risk of miscarriage (three-fold) and operative delivery (20.7 versus 33.8% in the obese and 47.4% in the morbidly obese group). Other risks to the mother include an increased risk of pre-eclampsia (3.9 versus 13.5% in the obese group) and thromboembolism (0.05 versus 0.12% in the obese group). There are risks to the fetus with increased perinatal mortality (1.4 per 1000 versus 5.7 per 1000 in the obese group) and macrosomia (>90th centile; 9 versus 17.5% in the obese group). Maternal obesity is associated with an increased risk of obesity in the long term. Obese woman should try to lose weight before pregnancy but probably not during pregnancy. There is no real evidence base for the management of maternal obesity but some practical suggestions are made.

The relationship of insulin insensitivity to menstrual pattern in women with hyperandrogenism and polycystic ovaries

OBJECTIVE

Insulin insensitivity is a recognized feature of polycystic ovary syndrome (PCOS) but previous studies have suggested that circulating insulin concentrations are normal in hyperandrogenaemic women with regular cycles. The aim of this study was to examine the relationship between insulin sensitivity and menstrual pattern in women with PCO.

DESIGN

A cross-sectional study of insulin sensitivity in a cohort of PCO subjects with oligomenorrhoea compared to women with PCO and regular menstrual cycles and a group of normal control subjects.

SUBJECTS

Seventy-two women with polycystic ovaries on ultrasonography were studied. PCO subjects had clinical and/or biochemical evidence of hyperandrogenism; 53 had oligo/amenorrhoea (olig) and 19 had regular menses (reg). Results were compared with 31 control subjects. The groups were matched for age, weight and ethnic origin.

METHODS

Glucose and insulin responses to 75 g oral glucose were measured. Insulin sensitivity was assessed by the decline in plasma glucose following intravenous insulin (0.05 U/kg).

RESULTS

Glucose area (mean +/- SEM) after oral glucose was increased slightly in both PCO groups compared with controls (olig 37.6 +/- 1.4, reg 36.0 +/- 1.8, control 33.7 +/- 0.9 mmol/l h, both P < 0.01). Insulin area median (interquartile range) in response to glucose was significantly greater in the oligomenorrhoeic group (346 (239-734) mU/l h), compared with both PCO with regular cycles (246 (148-355), P < 0.01) and controls (221 (147-277), P < 0.01). Insulin sensitivity was reduced (P < 0.01) in the oligomenorrhoeic group (147 +/- 9.2 mumol/l min) compared to controls (185 +/- 7.4) but was normal in PCO with regular cycles (182 +/- 12.5). Insulin sensitivity did not correlate significantly with plasma testosterone or with SHBG levels, but plasma insulin concentrations correlated negatively with SHBG levels (fasting insulin vs SHBG, r = -0.47, P < 0.01; insulin area vs SHBG, r = -0.41, P < 0.01).

CONCLUSIONS

Insulin insensitivity in polycystic ovary syndrome occurs when there is oligo/amenorrhoea but not when the menstrual cycle is regular. This is consistent with PCO and insulin insensitivity being separate abnormalities which when combined are associated with anovulation.

Neonatal bone mass: influence of parental birthweight, maternal smoking, body composition, and activity during pregnancy

Evidence is accumulating that intrauterine growth and development may influence an individual's risk of osteoporosis in later adult life. To examine maternal and paternal influences on intrauterine skeletal growth, we used dual-energy X-ray absorptiometry to measure the neonatal bone mineral content (BMC) and bone mineral density (BMD) of 145 infants born at term. Independently of the infant's duration of gestation at birth, the birthweights of both parents and the height of the father were positively correlated with neonatal whole body BMC. Women who smoked during pregnancy had infants with a lower whole body BMC and BMD; overall, there was a 7.1-g (11%) average difference between whole body BMC of infants whose mothers did and did not smoke during pregnancy (p = 0.005). Women with thinner triceps skinfold thicknesses (reflecting lower fat stores) and those who reported a faster walking pace and more frequent vigorous activity in late pregnancy also tended to have infants with a lower BMC and BMD (p values for BMC; 0.02, 0.03, and 0.05, respectively). Maternal thinness and faster walking pace but not maternal smoking or parental birthweight also were associated with lower bone mineral apparent density (BMAD). The influences on skeletal growth and mineralization were independent of placental weight, a marker of the placental capacity to deliver nutrients to the fetus. These observations point to a combination of genetic and intrauterine environmental influences on prenatal skeletal development and suggest that environmental modulation, even at this early stage of life, may reduce the risk of osteoporosis in adulthood.

A TEM study of two water-based adhesive systems bonded to dry and wet dentin

To keep the exposed collagen scaffold penetrable to resin, it has been recommended that the conditioned dentin surface be maintained in a visibly moist condition, a clinical technique commonly referred to as wet bonding. In this study, resin-dentin interfaces produced with two water-based adhesive systems--OptiBond (OPTI, Kerr) and Scotchbond Multi-Purpose (SBMP, 3M)--were compared by transmission electron microscopy, following the application of either a dry- or a wet-bonding technique. The hypothesis advanced was that the ultramorphology of the hybrid layer would differ depending on which bonding method was applied. A morphologically well-organized hybrid layer of collagen fibrils intermingled with resin in tiny interfibrillar channels was consistently formed by the OPTI system. The SBMP system was found to produce a hybrid layer with a more variable ultrastructure, less distinctly outlined collagen fibrils, and a characteristic electron-dense phase located at its surface. No major differences in hybrid layer ultrastructure were observed when the two adhesive systems investigated were bonded to either dry or wet dentin. When the adhesives were dry-bonded, no ultrastructural evidence of collapsed demineralized collagen, incompletely or not at all infiltrated by resin, could be detected. In addition, when the two adhesives were bonded to wet dentin, no signs of overwetting phenomena, that would have indicated that water was ineffectively removed, were apparent. It has been hypothesized that the amount of water provided with the hydrophilic primer solution of either of the two adhesive systems investigated suffices to re-hydrate and re-expand the gently air-dried and collapsed collagen network. Further research should be directed to determine whether this hypothesized self-rewetting effect can be extrapolated to other adhesive systems that provide water-based primers.

Neuronal-glial interactions and behaviour

Both neurons and glia interact dynamically to enable information processing and behaviour. They have had increasingly intimate, numerous and differentiated associations during brain evolution. Radial glia form a scaffold for neuronal developmental migration and astrocytes enable later synapse elimination. Functionally syncytial glial cells are depolarised by elevated potassium to generate slow potential shifts that are quantitatively related to arousal, levels of motivation and accompany learning. Potassium stimulates astrocytic glycogenolysis and neuronal oxidative metabolism, the former of which is necessary for passive avoidance learning in chicks. Neurons oxidatively metabolise lactate/pyruvate derived from astrocytic glycolysis as their major energy source, stimulated by elevated glutamate. In astrocytes, noradrenaline activates both glycogenolysis and oxidative metabolism. Neuronal glutamate depends crucially on the supply of astrocytically derived glutamine. Released glutamate depolarises astrocytes and their handling of potassium and induces waves of elevated intracellular calcium. Serotonin causes astrocytic hyperpolarisation. Astrocytes alter their physical relationships with neurons to regulate neuronal communication in the hypothalamus during lactation, parturition and dehydration and in response to steroid hormones. There is also structural plasticity of astrocytes during learning in cortex and cerebellum.

Estrogen receptor (ER)alpha and ERbeta exhibit unique pharmacologic properties when coupled to activation of the mitogen-activated protein kinase pathway

The rapid, nongenomic effects of estrogen are increasingly recognized as playing an important role in several aspects of estrogen action. Rapid activation of the mitogen-activated protein kinase (MAPK) signaling pathway by estrogen is among the more recently identified of these effects. To explore the role of estrogen receptors (ERs) in mediating these effects, we have transfected ER-negative Rat-2 fibroblasts with complementary DNA clones encoding either human ERalpha or rat ERbeta and examined their ability to couple to activation of MAPK in response to 17beta-estradiol (17beta-E(2)) and other ligands. For both receptors, addition of E(2) resulted in a rapid phosphorylation of MAPK. Activation of MAPK in ERalpha-transfected cells was partially and completely blocked by the antiestrogens tamoxifen and ICI 182,780, respectively. In ERbeta-transfected cells, MAPK activation was less sensitive to inhibition by tamoxifen and ICI 182,780. We have also observed that, in this model system, a membrane-impermeable estrogen (BSA-E(2)) and 17alpha-E(2) were both able to activate MAPK in a manner similar to E(2) alone. Here also, ICI 182,780 blocked the ability of BSA-E(2) to activate MAPK through ERalpha, but failed to block ERbeta-mediated effects. BSA-E(2) treatment, however, failed to activate nuclear estrogen-response-element-mediated gene transcription. These data show that these nuclear ERs are necessary for estrogen's effects at the membrane. This model system will be useful in identifying molecular interactions involved in the rapid effects mediated by the ERs.

Synaptogenesis in the Hippocampal CA1 Field following Traumatic Brain Injury

Traumatic brain injury (TBI) results in both acute and chronic disruption of cognitive ability that may be mediated through a disruption of hippocampal circuitry. Experimental models of TBI have demonstrated that cortical contusion injuries can result in the loss of specific neurons in the CA3 subfield of the ipsilateral hippocampus, resulting in partial loss of afferents to the CA1 subfield. Numerous studies have documented the ability of the central nervous system to compensate for deafferentation by initiating a plasticity response capable of restoring lost synaptic contacts. The present study was designed to examine the time course of loss and replacement of synaptic contacts in stratum radiatum dendritic field of CA1. Young adult rats were subjected to a lateral cortical contusion injury and assayed for total synaptic numbers using unbiased stereology coupled with transmission electron microscopy. Injured animals demonstrated a 60% loss of synapses in CA1 at 2 days post-injury, followed by a reinnervation process that was apparent as early as 10 days post-injury. By 60 days post-injury, total synaptic numbers had approached pre-injury levels but were still significantly lower. Some animals were behaviorally tested for spatial memory in a Morris Water Maze at 15 and 30 days post-injury. While there was some improvement in spatial memory, injured animals continued to demonstrate a significant deficit in acquisition. These results show that the hippocampus ipsilateral to the cortical contusion is capable of a significant plasticity response but that synapse replacement in this area does not necessarily result in significant improvement in spatial learning.

Vitamin D deficiency and supplementation during pregnancy

OBJECTIVE

Vitamin D is essential for skeletal health and prolonged deficiency results in infantile rickets and adult osteomalacia. The aim of this study is to determine the vitamin D status in pregnancy and to evaluate the effects of daily and of single-dose vitamin D supplementation.

DESIGN

A prospective randomized study at St Mary's Hospital London.

PATIENTS

A total of 180 women (Indian Asian, Middle Eastern, Black and Caucasian) were recruited at 27 weeks gestation and randomized into three treatment groups: a single oral dose of 200,000 IU vitamin D, a daily supplement of 800 IU vitamin D from 27 weeks until delivery and a no treatment group.

MEASUREMENTS

Vitamin D (25-hydroxyvitamin D), PTH and corrected calcium levels in mothers at 27 weeks and at delivery and cord 25-hydroxyvitamin D and corrected calcium levels.

RESULTS

The final maternal 25-hydroxyvitamin D levels were significantly higher in the supplemented group [daily dose (median) 42 (IQR 31-76) nmol/l, stat dose (median) 34 (IQR 30-46) nmol/l vs. median 27 (IQR 27-39) nmol/l in the no treatment; P < 0.0001] and significantly fewer women with secondary hyperparathyroidism in the supplemented group (10% in daily dose vs. 12% in stat dose vs. 27% in the no treatment; P < 0.05). Cord 25-hydroxyvitamin D levels were significantly higher with supplementation [daily dose median 26 (IQR 17-45) nmol/l, stat dose median 25 (IQR 18-34) nmol/l vs. median 17 (IQR 14-22) nmol/l in no treatment; P = 0.001].

CONCLUSION

Single or daily dose improved 25-hydroxyvitamin D levels significantly. However, even with supplementation, only a small percentage of women and babies were vitamin D sufficient. Further research is required to determine the optimal timing and dosing of vitamin D in pregnancy.

TGF-beta 1-induced inhibition of mouse mammary ductal growth: developmental specificity and characterization

TGF-beta 1, implanted into growing mouse mammary glands, was previously shown to inhibit ductal growth in an apparently normal and fully reversible manner. In this report we extend these findings to show that TGF-beta 1 inhibition is highly specific. In pregnant or hormone-treated mice, doses of TGF-beta 1 that were capable of fully inhibiting ductal elongation had little effect on the proliferation of lobuloalveolar structures. Additionally, the inhibitory action of TGF-beta 1 on ducts is epithelium-specific, resulting in cessation of DNA synthesis in the rapidly proliferating epithelium of mammary end buds, but does not inhibit DNA synthesis in the stroma surrounding the end buds. At the cellular level, transplant studies showed that TGF-beta 1 inhibited the regeneration of mammary ductal cells when implanted into mammary gland-free fat pads by suppressing the formation of new end buds, without inhibiting maintenance DNA synthesis in ductal lumenal epithelium; this observation indicates the potential of TGF-beta 1 to maintain patterning by suppressing adventitious lateral branching. The time-course of TGF-beta 1 inhibition of end buds was rapid, with cessation of DNA synthesis by 12 hr, followed by loss of the stem cell (cap cell) layer. The question of glandular exposure to TGF-beta 1 administered in EVAc implants was also investigated. Incorporation of TGF-beta 1 into EVAc was found not to degrade the hormone, while the release kinetics of the ligand from implants, its retention in the gland, and the demonstrable zone of exposure were consistent with observed inhibitory effects. These results support the hypothesis that TGF-beta 1 is a natural regulator of mammary ductal growth.

Birth weight and body fat distribution in adolescent girls

OBJECTIVE

To examine the association between birth weight and body fat distribution in a group of adolescent girls.

DESIGN

A total of 216 white girls who were born in Southampton had their heights, weights, waist and hip circumferences, and skinfold thicknesses measured when they were aged between 14 and 16 years.

RESULTS

The girls who were smallest at birth, but who were fattest at time of measurement were the most centrally obese. In girls whose body mass index was above the median (21 kg/m2), the subscapular to triceps skinfold ratio rose by 9% for every kilogram decrease in birth weight. Among overweight girls, with a body mass index over 25, the ratio rose by 27% for every kilogram decrease in birth weight.

CONCLUSION

In adolescent girls, the tendency to store fat on the trunk rather than the limbs, seems to be programmed by growth in fetal life, and is most evident in those who are overweight.

The ratio of 2nd to 4th digit length and male homosexuality

Sexual orientation may be influenced by prenatal levels of testosterone and oestrogen. There is evidence that the ratio of the length of 2nd and 4th digits (2D:4D) is negatively related to prenatal testosterone and positively to oestrogen. We report that (a) 2D:4D was lower in a sample of 88 homosexual men than in 88 sex- and age-matched controls recruited without regard to sexual orientation, (b) within the homosexual sample, there was a significant positive relationship between mean 2D:4D ratio and exclusive homosexuality, (c) overall, there was a decrease in 2D:4D from controls to homosexual men to bisexual men and (d) fraternal birth order, a positive predictor of male homosexuality, was not associated with 2D:4D in a sample of 240 Caucasian men recruited without regard to sexual orientation and 45 homosexual men.Further work is needed to confirm the relationships between 2D:4D and sexual orientation. However, these and other recent data tend to support an association between male homosexuality and high fetal testosterone. Very high testosterone levels may be associated with a sexual preference for both men and women.

Increasing antioxidant levels in tomatoes through modification of the flavonoid biosynthetic pathway

Flavonoids are a diverse group of phenolic secondary metabolites that occur naturally in plants and therefore form an integral component of the human diet. Many of the compounds belonging to this group are potent antioxidants in vitro and epidemiological studies suggest a direct correlation between high flavonoid intake and decreased risk of cardiovascular disease, cancer and other age-related diseases. Enhancing flavonoid biosynthesis in chosen crops may provide new raw materials that have the potential to be used in foods designed for specific benefits to human health. Using genetic modification, it was possible to generate several tomato lines with significantly altered flavonoid content and to probe the role and importance of several key enzymatic steps in the tomato flavonoid biosynthetic pathway. Most notably an up to 78-fold increase in total fruit flavonols was achieved through ectopic expression of a single biosynthetic enzyme, chalcone isomerase. In addition, chalcone synthase and flavonol synthase transgenes were found to act synergistically to up-regulate flavonol biosynthesis significantly in tomato flesh tissues.