Anemic African children carry an unfavorable ratio of fecal enterobacteria to bifidobacteria and lactobacilli, which is increased by iron fortification. Thus, iron fortification in this population produces a potentially more pathogenic gut microbiota profile, and this profile is associated with increased gut inflammation. This trial was registered at controlled-trials.com as ISRCTN21782274.

Memory T cells can be divided into central–memory (TCM) and effector–memory (TEM) cells, which differ in their functional properties. Although both subpopulations can persist long term, it is not known whether they are maintained by similar mechanisms. We used in vivo labeling with deuterated glucose to measure the turnover of CD4+ T cells in healthy humans. The CD45R0+CCR7− TEM subpopulation was shown to have a rapid proliferation rate of 4.7% per day compared with 1.5% per day for CD45R0+CCR7+ TCM cells; these values are equivalent to average intermitotic (doubling) times of 15 and 48 d, respectively. In contrast, the CD45RA+CCR7+ naive CD4+ T cell population was found to be much longer lived, being labeled at a rate of only 0.2% per day (corresponding to an intermitotic time of approximately 1 yr). These data indicate that human CD4+ TEM cells constitute a short-lived cell population that requires continuous replenishment in vivo.

Summary Human natural killer (NK) cells form a circulating population in a state of dynamic homeostasis. We investigated NK cell homeostasis by labelling dividing cells in vivo using deuterium‐enriched glucose in young and elderly healthy subjects and patients with viral infection. Following a 24‐hr intravenous infusion of 6,6‐D2‐glucose, CD3– CD16+ NK cells sorted from peripheral blood mononuclear cells (PBMC) by fluorescence‐activated cell sorter (FACS) were analysed for DNA deuterium content by gas chromatography mass spectrometry to yield minimum estimates for proliferation rate (p). In healthy young adults (n = 5), deuterium enrichment was maximal ∼ 10 days after labelling, consistent with postmitotic maturation preceding circulation. The mean (± standard deviation) proliferation rate was 4·3 ± 2·4%/day (equivalent to a doubling time of 16 days) and the total production rate was 15 ± 7·6 × 106 cells/l/day. Labelled cells disappeared from the circulation at a similar rate [6·9 ± 4·0%/day; half‐life (T½) < 10 days]. Healthy elderly subjects (n = 8) had lower proliferation and production rates (P = 2·5 ± 1·0%/day and 7·3 ± 3·7 × 106 cells/l/day, respectively; P = 0·04). Similar rates were seen in patients chronically infected with human T‐cell lymphotropic virus type I (HTLV‐I) (P = 3·2 ± 1·9%/day). In acute infectious mononucleosis (n = 5), NK cell numbers were increased but kinetics were unaffected (P = 2·8 ± 1·0%/day) a mean of 12 days after symptom onset. Human NK cells have a turnover time in blood of about 2 weeks. Proliferation rates appear to fall with ageing, remain unperturbed by chronic HTLV‐I infection and normalize rapidly following acute Epstein–Barr virus infection.

The ability to measure, describe and interpret T cell kinetics is pivotal in understanding normal lymphocyte homeostasis and diseases that affect T cell numbers. Following in vivo labeling of dividing cells with 6,6-D 2 -glucose in eight healthy volunteers, peripheral blood T cells were sorted by CD4, CD8 and CD45 phenotype. Enrichment of deuterium in DNA was measured by gas chromatography-mass spectrometry. A novel model of T cell kinetics, allowing for heterogeneity within T cell pools, was used to analyze data on acquisition and loss of label and calculate proliferation and disappearance rates for each subpopulation. CD8+ lymphocytes and CD45RA + CD4 + lymphocytes had slower proliferation rates, 0.5% and 0.6% / day, respectively (doubling time about 4 months). Disappearance rates of labeled cells were similar for all cell types (7%-12% / day) and exceeded corresponding proliferation rates. This disparity may be understood conceptually in terms of either phenotypic heterogeneity (rapid versus slow turnover pools), or history (recently divided cells are more likely to die). The new kinetic model fits the data closely and avoids the need to postulate a large external source of lymphocytes to maintain equilibrium.

BackgroundPhysical inactivity is associated with excess weight and adverse health outcomes. We synthesize the evidence on physical inactivity and its social determinants in Arab countries, with special attention to gender and cultural context.MethodsWe searched MEDLINE, Popline, and SSCI for articles published between 2000 and 2016, assessing the prevalence of physical inactivity and its social determinants. We also included national survey reports on physical activity, and searched for analyses of the social context of physical activity.ResultsWe found 172 articles meeting inclusion criteria. Standardized data are available from surveys by the World Health Organization for almost all countries, but journal articles show great variability in definitions, measurements and methodology. Prevalence of inactivity among adults and children/adolescents is high across countries, and is higher among women. Some determinants of physical inactivity in the region (age, gender, low education) are shared with other regions, but specific aspects of the cultural context of the region seem particularly discouraging of physical activity. We draw on social science studies to gain insights into why this is so.ConclusionsPhysical inactivity among Arab adults and children/adolescents is high. Studies using harmonized approaches, rigorous analytic techniques and a deeper examination of context are needed to design appropriate interventions.Electronic supplementary materialThe online version of this article (10.1186/s12889-018-5472-z) contains supplementary material, which is available to authorized users.

Information about the kinetic behavior and lifespan of lymphocytes is crucial to understanding the mechanisms that regulate processes such as immunologic memory. We have used in vivo labeling of dividing cells with 6,6-2 H 2 -glucose, combined with cell sorting and gas-chromatography-mass spectrometry for deuterium enrichment, in order to analyze the kinetics of human total, naive, or memory B lymphocytes, separated from peripheral blood using monoclonal antibodies. We show that total blood B cells of young adults divide at an average rate of 1.9% (؎1.0%) per day and at a similar though slightly slower rate, 1.5% (

IntroductionWomen and children account for a disproportionate morbidity burden among conflict-affected populations, and yet they are not included in global accountability frameworks for women’s and children’s health. We use Countdown to 2015 (Millennium Development Goals) health indicators to provide an up-to-date review and analysis of the best available data on Syrian refugees in Jordan, Lebanon and Turkey and internally displaced within Syria and explore data challenges in this conflict setting.MethodsWe searched Medline, PubMed, Scopus, Popline and Index Medicus for WHO Eastern Mediterranean Region Office and relevant development/humanitarian databases in all languages from January 2011 until December 2015. We met in person or emailed relevant key stakeholders in Lebanon, Jordan, Syria and Turkey to obtain any unpublished or missing data. We convened a meeting of experts working with these populations to discuss the results.ResultsThe following trends were found based on available data for these populations as compared with preconflict Syria. Birth registration in Syria and in host neighbouring countries decreased and was very low in Lebanon. In Syria, the infant mortality rate and under-five mortality rate increased, and coverage of antenatal care (one visit with a skilled attendant), skilled birth attendance and vaccination (except for DTP3 vaccine) declined. The number of Syrian refugee women attending more than four antenatal care visits was low in Lebanon and in non-camp settings in Jordan. Few data were available on these indicators among the internally displaced. In conflict settings such as that of Syria, coverage rates of interventions are often unknown or difficult to ascertain because of measurement challenges in accessing conflict-affected populations or to the inability to determine relevant denominators in this dynamic setting.ConclusionResearch, monitoring and evaluation in humanitarian settings could better inform public health interventions if findings were more widely shared, methodologies were more explicit and globally agreed definitions and indicators were used consistently.

BackgroundSince the beginning of the Syrian conflict in 2011, Jordan, Lebanon and Turkey have hosted large refugee populations, with a high pre-conflict burden of non-communicable diseases (NCDs).ObjectivesWe aimed to describe the ways in which these three host country health systems have provided NCD services to Syrian refugees over time, and to highlight the successes and challenges they encountered.MethodsWe conducted a descriptive review of the academic and grey literature, published between March 2011 and March 2017, using PubMed and Google searches complemented with documents provided by relevant stakeholders.ResultsForty-one articles and reports met our search criteria. Despite the scarcity of systematic population-level data, these documents highlight the high burden of reported NCDs among Syrian refugees, especially amongst older adults. The three host countries utilized different approaches to the design, delivery and financing of NCD services for these refugees. In Jordan and Lebanon, Ministries of Health and the United Nations High Commissioner for Refugees (UNHCR) coordinate a diverse group of health care providers to deliver health services to Syrian refugees at a subsidized cost. In Turkey, however, services are provided solely by the Disaster and Emergency Management Presidency (AFAD), a Turkish governmental agency, with no cost to patients for primary or secondary care. Access to NCD services varied both within and between countries, with no data available from Turkey. The cost of NCD treatment is the primary barrier to accessing healthcare, with high out-of-pocket payments required for medications and secondary and tertiary care services, despite the availability of free or subsidized primary health services. Financial impediments led refugees to adopt coping strategies, including returning to Syria to seek treatment, with associated frequent treatment interruptions. These gaps were compounded by health system related barriers such as complex referral systems, lack of effective guidance on navigating the health system, limited health facility capacity and suboptimal NCD health education.ConclusionAs funding shortages for refugee services continue, innovative service delivery models are needed to create responsive and sustainable solutions to the NCD burden among refugees in host countries.Electronic supplementary materialThe online version of this article (10.1186/s13031-019-0192-2) contains supplementary material, which is available to authorized users.