Stephen Owens

Periconceptional maternal micronutrient supplementation is associated with widespread gender related changes in the epigenome: a study of a unique resource in the Gambia

In addition to the genetic constitution inherited by an organism, the developmental trajectory and resulting mature phenotype are also determined by mechanisms acting during critical windows in early life that influence and establish stable patterns of gene expression. This is the crux of the developmental origins of health and disease hypothesis that suggests undernutrition during gestation and infancy predisposes to ill health in later life. The hypothesis that periconceptional maternal micronutrient supplementation might affect fetal genome-wide methylation within gene promoters was explored in cord blood samples from offspring of Gambian women enrolled into a unique randomized, double blind controlled trial. Significant changes in the epigenome in cord blood DNA samples were further explored in a subset of offspring at 9 months. Gender-specific changes related to periconceptional nutritional supplementation were identified in cord blood DNA samples, some of which showed persistent changes in infant blood DNA samples. Significant effects of periconceptional micronutrient supplementation were also observed in postnatal samples which were not evident in cord blood. In this Gambian population, the increased death rate of individuals born in nutritionally poor seasons has been related to infection and it is of interest that we identified differential methylation at genes associated with defence against infection and immune response. Although the sample size was relatively small, these pilot data suggest that periconceptional nutrition in humans is an important determinant of newborn whole genome methylation patterns but may also influence postnatal developmental patterns of gene promoter methylation linking early with disease risk.

DNA methylation profiling at imprinted loci after periconceptional micronutrient supplementation in humans: results of a pilot randomized controlled trial

Intrauterine exposures mediated by maternal diet may affect risk of cardiovascular disease, obesity, and type 2 diabetes. Recent evidence, primarily from animal studies and observational data in humans, suggests that the epigenome can be altered by maternal diet during the periconceptional period and that these programming events may underlie later disease risk. A randomized controlled trial of periconceptional micronutrient supplementation in The Gambia, where seasonal nutritional variations affect fetal growth and postnatal outcomes, provided a unique opportunity to test this hypothesis. Specifically, we targeted imprinted genes, which play important roles in allocation of maternal resources while being epigenetically regulated. DNA methylation at 12 differentially methylated regions (DMRs) was analyzed in cord blood samples from 58 offspring of women participating in a doubleblind randomized‐controlled trial of pre‐ and periconceptional micronutrient supplementation (including folate, zinc, and vitamins A, B, C, and D). We observed sex‐specific effects of micronutrient supplementation, reducing methylation levels at two of the DMRs analyzed, IGF2R in girls and GTL2‐2 in boys. This pilot study is the first to analyze DNA methylation in the context of a randomized controlled trial, and it provides suggestive evidence that periconceptional maternal nutrition alters offspring methylation at imprinted loci.—Cooper, W. N., Khulan, B., Owens, S., Elks, C. E., Seidel, V., Prentice, A. M., Belteki, G., Ong, K. K., Affara, N. A., Constância, M., Dunger, D. B. DNA methylation profiling at imprinted loci after periconceptional micronutrient supplementation in humans: results of a pilot randomized controlled trial. FASEB J. 26, 1782‐1790 (2012). www.fasebj.org

ABO Blood Group Phenotypes and Plasmodium falciparum Malaria: Unlocking a Pivotal Mechanism

Host susceptibility to Plasmodium falciparum infection is central for improved understanding of malaria in human populations. Red blood cell (RBC) polymorphisms have been proposed as factors associated with malaria infection or its severity, although no systematic appraisal of ABO phenotypes and malaria risk has been undertaken. This analysis summarises epidemiological, clinical and immunological evidence on the nature of ABO histo-blood antigens and their interaction with malaria in terms of population genetics, infection risk, severe malaria and placental malaria. In non-pregnant subjects, a meta-analysis showed no conclusive evidence associating ABO phenotypes with risk of uncomplicated malaria. There was stronger evidence that ABO phenotype modulates severity of P. falciparum malaria, with group A associated with severe disease and blood group O with milder disease. Among pregnant subjects, group O was associated with increased risk of placental malaria in primigravidae and reduced risk in multigravidae. The biological basis for ABO-related susceptibility to malaria is reviewed. Several mechanisms relate to these associations including affinity for Anopheles gambiae; shared ABO antigens with P. falciparum; impairment of merozoite penetration of RBCs; and cytoadherence, endothelial activation and rosetting. ABO phenotypic associations with malaria are related to its pathogenesis and improved understanding of these interactions is required for understanding the glycobiology of malaria infection.

An adaptive expert system approach for intrusion detection

Intrusion detection is a type of computer network security system that attempts toidentify inappropriate use of the system. As more corporate computer systems become linked to the internet and as more stakeholder transactions take place between systems, the identification and prevention of computer network misuse becomes increasingly critical. Expert system technology is often used to construct intruder detection systems. However, Intrusion Detection System (IDS) researchers have tended to build systems that are hard to manage, lack intuitive user interfaces and are cumbersome to use in real-live situations. In this paper, we present an adaptive expert system for intrusion detection that utilises fuzzy sets. This system has the ability to adapt to the type and/or degree of threat and is relatively simple to implement when used with computer system networks. Examples of rule sets are presented. The adaptive ability of the system is demonstrated by experimenting with the system using Clips 6.10.

The right to remain silent: a qualitative study of the medical and social ramifications of pregnancy disclosure for Gambian women

Objectives  Control of infectious diseases in developing countries often requires using drugs that are contraindicated during pregnancy. Avoiding inadvertent exposure to drugs involves women (a) recognising pregnancy early, (b) disclosing the pregnancy to health workers and (c) using medicines in an informed manner. We explored these factors to inform and improve the process by which health workers provide care and treatment to pregnant women.

The Adductor Hallucis Revisited

To evaluate anatomic variability in the insertion of the adductor hallucis into the lateral sesamoid and proximal phalanx of the great toe and to evaluate the extent of release of the adductor hallucis tendon performed through an incision in the dorsal first-web space, we recorded the angle of hallux valgus in 42 fresh-frozen specimens from human cadavers. An incision was made for a realignment of the soft tissues, dissecting down to the level of the intermetatarsal ligament. A loop of suture was placed around the identifiable adductor hallucis tendon through this incision along the lateral aspect of the lateral sesamoid. Then a plantar dissection removed all soft tissue to the level of the intermetatarsal ligament, adductor hallucis (transverse and oblique heads), lateral sesamoid, and lateral flexor hallucis brevis. The insertion of these muscles into the proximal phalanx was evaluated. Specifically, we looked for separate slips of the adductor tendon inserting into the base of the proximal phalanx or separate insertions of the adductor tendon and the tendon of the flexor hallucis brevis muscle. In 33 of the 42 specimens, the entire adductor hallucis tendon had been isolated by the loop of suture through the incision in the dorsal first web. In eight of the remaining nine specimens, a small slip of the tendon (comprising less than 25% of its substance) had not been included. No specimen was found to have a separate slip of the adductor tendon inserting into the base of the proximal phalanx. Instead, all specimens were found to have only a conjoined insertion of fibers of the adductor hallucis and of the flexor hallucis brevis from the lateral sesamoid into the base of the proximal phalanx. We did not identify a separate tendon-insertion into the proximal phalanx in any specimen. Therefore, great caution should be exercised in releasing an isolated insertion of the adductor tendon from the base of the proximal phalanx of the great toe since it may actually represent the conjoined insertion of the lateral flexor hallucis brevis tendon and the adductor tendon. We found that by simply releasing the adductor tendon from its insertion along the lateral aspect of the sesamoid, accomplished through an incision in the dorsal first web, that an adequate release was achieved in most specimens.

Evaluating the impact of electronic data interchange on the ingredient supply chain of a food processing company

A model of an electronic data interchange (EDI) enabled ingredient supply chain for a food processing company was developed, the model was simulated and its performance was compared with a simulation model of the current ingredient supply chain process of a US food processing company. The simulation results indicated that an EDI enabled system, which removed many of the time delays associated with the current process, significantly reduced swings in raw materials inventory and allowed significant reductions in raw materials safety stock without increasing the risk of production delays due to out‐of‐stock ingredients.

Sequential decisions on FAS sequencing guided by biomarkers in patients with lymphoproliferation and autoimmune cytopenia

Clinical and genetic heterogeneity renders confirmation or exclusion of autoimmune lymphoproliferative syndrome difficult. To re-evaluate and improve the currently suggested diagnostic approach to patients with suspected FAS mutation, the most frequent cause of autoimmune lymphoproliferative syndrome, we prospectively determined 11 biomarkers in 163 patients with splenomegaly or lymphadenopathy and presumed or proven autoimmune cytopenia(s). Among 98 patients sequenced for FAS mutations in CD3+TCRα/β+CD4−CD8− “double negative” T cells, 32 had germline and six had somatic FAS mutations. The best a priori predictor of FAS mutations was the combination of vitamin B12 and soluble FAS ligand (cut-offs 1255 pg/mL and 559 pg/mL, respectively), which had a positive predictive value of 92% and a negative predictive value of 97%. We used these data to develop a web-based probability calculator for FAS mutations using the three most discriminatory biomarkers (vitamin B12, soluble FAS ligand, interleukin-10) of the 11 tested. Since more than 60% of patients with lymphoproliferation and autoimmune cytopenia(s) in our cohort did not harbor FAS mutations, 15% had somatic FAS mutations, and the predictive value of double-negative T-cell values was rather low (positive and negative predictive values of 61% and 77%, respectively), we argue that the previously suggested diagnostic algorithm based on determination of double-negative T cells and germline FAS sequencing, followed by biomarker analysis, is not efficient. We propose vitamin B12 and soluble FAS ligand assessment as the initial diagnostic step with subsequent decision on FAS sequencing supported by a probability-calculating tool.

Periconceptional multiple-micronutrient supplementation and placental function in rural Gambian women: a double-blind, randomized, placebo-controlled trial

Background: Maternal micronutrient deficiencies are commonly associated with clinical indicators of placental dysfunction. Objective: We tested the hypothesis that periconceptional multiple-micronutrient supplementation (MMS) affects placental function. Design: We conducted a double-blind, randomized, placebo-controlled trial of MMS in 17- to 45-y-old Gambian women who were menstruating regularly and within the previous 3 mo. Eligible subjects were pre–randomly assigned to supplementation with the UNICEF/WHO/United Nations University multiple micronutrient preparation (UNIMMAP) or placebo on recruitment and until they reached their first antenatal check-up or for 1 y if they failed to conceive. Primary outcome measures were midgestational indexes of utero-placental vascular-endothelial function [ratio of plasminogen-activator inhibitor (PAI) 1 to PAI-2 and mean uterine-artery resistance index (UtARI)] and placental active transport capacity at delivery [fetal to maternal measles antibody (MMA) ratio]. Results: We recruited 1156 women who yielded 415 pregnancies, of which 376 met all of the inclusion criteria. With adjustment for gestational age at sampling, there were no differences in PAI-1 to PAI-2 or MMA ratios between trial arms, but there was a 0.02-unit reduction in UtARI between 18 and 32 wk of gestation (95% CI: −0.03, −0.00; P = 0.040) in women taking UNIMMAP. Conclusions: Placental vascular function was modifiable by periconceptional micronutrient supplementation. However, the effect was small and supplementation did not further affect other variables of placental function. This trial was registered at www.controlled-trials.com as ISRCTN 13687662.

Re: Clinical trials in tropical diseases: a politically incorrect view.

Your recently published editorial by White (2006) is strongly critical of the incorporation of current Good Clinical Practice (GCP) guidelines into clinical trials in the tropics. While he is to be commended for his principled stance on balancing high ethical and clinical standards with a workable approach to the procedural aspects of research, Professor White dismisses the role that GCP can play in maintaining this balance. In essence, GCP is a standard for the design, conduct and reporting of trials involving human subjects. Compliance with such a standard is the only way to facilitate public assurance that the data reported are accurate and credible and that the rights and safety of trial subjects are protected, consistent with biomedical ethical principles originating in the Declaration of Helsinki. Of course, compliance on paper is no guarantee of adherence in practice but there should be no doubt that a single reference standard for GCP is preferable to no standard at all. The question is what this should be. In order to provide a regulatory standard for GCP for use by the pharmaceutical industry in the European Union, United States and Japan, the International Conference on Harmonisation (ICH) GCP Tripartite Guideline was published in 1996 (ICH 1996). The ICH Guideline is probably the most frequently referenced document pertaining to GCP in clinical trials and is presumably the industry standard that Professor White is so critical of. It is already widely recognized that the full provision of ICH GCP is not appropriate in non-commercial studies. Recent European Directives (2001/20/EC, 2005/28/EC) implemented in the UK through The Medicines for Human Use (Clinical Trials) Regulations 2004 are concerned with this very issue. However, the high regulatory trial standards that are rightfully demanded from the pharmaceutical industry may yet serve as a legitimate benchmark for all those carrying out non-commercial clinical trials in poor countries. That those high standards are difficult to achieve is precisely the point. It is important, however, that they are assessed in relation to individual trials and not the other way around. GCP could represent a generic toolbox from which components are selected and modified for specific studies. This model requires a flexible, realistic approach from sponsors, review panels and, crucially, by publishing journals. Trials could then be assessed on their GCP merits just as on other aspects of their designs. An appreciation of the principles and commercial context underpinning GCP, rather than a rejection of it, is therefore vital. The Medical Research Council (MRC) of the UK, in close consultation with the National Health Service Research and Development Programme published MRC Guidelines for Good Clinical Practice in Clinical Trials (Medical Research Council 1998). Although based on the 13 principles of the ICH Guideline, the MRC document addresses some of Professor White’s concerns, stating that they should be implemented without destroying the essential element of trust which underpins all research funding, or adding a cumbersome layer of bureaucracy (Medical Research Council 1998). Currently under review, the MRC guidelines attempt to distil the essence of good clinical practice into something simpler and more workable. Large, high-quality studies addressing important tropical research questions can be conducted to a high GCP standard, but doing so is not simple or cheap. This is evident from Cutts et al. (2006). At the present time, such projects do inevitably require strong financial and managerial support from wealthy organizations in the northern hemisphere, which are perhaps working to their own political, ethical and scientific agendas. The solution to this problem is not to reset the bar at a lower level for those working with fewer resources but to build capacity, striving to raise the bar to the same high level everywhere. Meanwhile, organizations like the MRC, the Wellcome Trust and sympathetic partners in the pharmaceutical industry have an obligation to continue to support good science around the world, which should be conducted to a high ethical standard and help to solve the most important global health problems. Sincerely Stephen Owens, Elizabeth Stokes and Jenny Mueller MRC Laboratories, Banjul, The Gambia