94 research outputs found
Sickle cell trait and Plasmodium fakiparum parasitaemia in pregnancy in Western Province, Kenya
Perspectives on the design and methodology of periconceptional nutrient supplementation trials.
Periconceptional supplementation could extend the period over which maternal and fetal nutrition is improved, but there are many challenges facing early-life intervention studies. Periconceptional trials differ from pregnancy supplementation trials, not only because of the very early or pre-gestational timing of nutrient exposure but also because they generate subsidiary information on participants who remain non-pregnant. The methodological challenges are more complex although, if well designed, they provide opportunities to evaluate concurrent hypotheses related to the health of non-pregnant women, especially nulliparous adolescents. This review examines the framework of published and ongoing randomised trial designs. Four cohorts typically arise from the periconceptional trial design--two of which are non-pregnant and two are pregnant--and this structure provides assessment options related to pre-pregnant, maternal, pregnancy and fetal outcomes. Conceptually the initial decision for single or micronutrient intervention is central--as is the choice of dosage and content--in order to establish a comparative framework across trials, improve standardisation, and facilitate interpretation of mechanistic hypotheses. Other trial features considered in the review include: measurement options for baseline and outcome assessments; adherence to long-term supplementation; sample size considerations in relation to duration of nutrient supplementation; cohort size for non-pregnant and pregnant cohorts as the latter is influenced by parity selection; integrating qualitative studies and data management issues. Emphasis is given to low resource settings where high infection rates and the possibility of nutrient-infection interactions may require appropriate safety monitoring. The focus is on pragmatic issues that may help investigators planning a periconceptional trial
The impact of endemic and epidemic malaria on the risk of stillbirth in two areas of Tanzania with different malaria transmission patterns
BACKGROUND: The impact of malaria on the risk of stillbirth is still under debate. The aim of the present analysis was to determine comparative changes in stillbirth prevalence between two areas of Tanzania with different malaria transmission patterns in order to estimate the malaria attributable component. METHODS: A retrospective analysis was completed of stillbirth differences between primigravidae and multigravidae in relation to malaria cases and transmission patterns for two different areas of Tanzania with a focus on the effects of the El Niño southern climatic oscillation (ENSO). One area, Kagera, experiences outbreaks of malaria, and the other area, Morogoro, is holoendemic. Delivery and malaria data were collected over a six year period from records of the two district hospitals in these locations. RESULTS: There was a significantly higher prevalence of low birthweight in primigravidae compared to multigravidae for both data sets. Low birthweight and stillbirth prevalence (17.5% and 4.8%) were significantly higher in Kilosa compared to Ndolage (11.9% and 2.4%). There was a significant difference in stillbirth prevalence between Ndolage and Kilosa between malaria seasons (2.4% and 5.6% respectively, p < 0.001) and during malaria seasons (1.9% and 5.9% respectively, p < 0.001). During ENSO there was no difference (4.1% and 4.9%, respectively). There was a significant difference in low birthweight prevalence between Ndolage and Kilosa between malaria seasons (14.4% and 23.0% respectively, p < 0.001) and in relation to malaria seasons (13.9% and 25.2% respectively, p < 0.001). During ENSO there was no difference (22.2% and 19.8%, respectively). Increased low birthweight risk occurred approximately five months following peak malaria prevalence, but stillbirth risk increased at the time of malaria peaks. CONCLUSION: Malaria exposure during pregnancy has a delayed effect on birthweight outcomes, but a more acute effect on stillbirth risk
Crystal structure of chlorido-methanol-(N-(2-(oxy)-3-methoxybenzylidene)pyridine-4-carbohydrazonato-κ3O,N,O′)-(4-methylphenyl)methyl-tin(IV), C23H24ClN3O4Sn
C23H24ClN3O4Sn, triclinic, P¯1 (no. 2), a=9.7536(2) Å,
b=10.0755(2) Å, c=12.4215(3) Å, α=84.928(2)°,
β=72.544(2)°, γ=74.382(2)°, V =1121.44(4) Å3, Z =2,
Rgt(F)=0.021, wRref(F2)=0.054, T =100(2) K
子宮頸部及び内膜における aromatase の局在と周期性変化
Objectives: To determine the role of maternal CYP1A1, GSTT1, and GSTM1 metabolic gene polymorphisms in modulating the association between pregnancy smoking exposure and fetal growth restriction.
Study design: A case-control study was conducted to investigate if the association of pregnancy smoking and birth outcome was modulated by maternal gene polymorphisms. A total of 90 mothers with an IUGR baby (cases) and 180 mothers without IUGR (controls) were enrolled.
Results: Almost half of smokers who carried a CYP1A1 variant (51.3%), GSTT1 null (43.6%), or GSTM1 null genotypes (64.1%) delivered a baby with IUGR. Smokers with the variant CYP1A1 "aa" genotype had babies with lower mean birthweight than non-smokers with the same genotype (p = 0.004). An interaction test showed increased prevalence of IUGR in smokers with the CYP1A1 (Aa/aa) variant (adjusted OR, 1.9; 95% CI, 1.4-5.5, p = 0.01), or with the GSTT1 null (AOR, 1.5; 1.1-3.1, p = 0.001), or GSTM1 null genotypes (AOR, 1.5; 1.2-3.7, p = 0.001).
Conclusions: Risk of fetal growth restriction in mothers who smoked during pregnancy was modulated by maternal metabolic gene polymorphisms. The genetic control of the conversion of toxic metabolites of tobacco smoke to less damaging substances is important for maternal and fetal health. (C) 2008 Elsevier Ireland Ltd. All rights reserved
ABO blood group phenotypes influence parity specific immunity to Plasmodium falciparum malaria in Malawian women
Background: Blood group O has been significantly associated with increased placental malaria infection in primiparae and reduced risk of infection in multiparae in the Gambia, an area with markedly seasonal malaria transmission. This study analyses the association between ABO blood group phenotypes in relation to placental malaria pathology and birth outcomes in southern Malawi, an area with perennial malaria transmission.
Methods: A cross- sectional study of 647 mother/ child pairs delivering in Montfort Hospital, Chikwawa District between February- June 2004 and January- July 2005 was undertaken. Maternal peripheral and cord blood samples were obtained at delivery. Placental tissue was obtained and malaria histology classified as active, past or no malaria infection. Birth anthropometry was recorded. ABO blood group was measured by agglutination.
Results: In primiparae, blood group O was significantly associated with increased risk of active placental infection ( OR 2.18, 95% CI 1.15 - 4.6, p = 0.02) and an increased foetal- placental weight ratio compared to non- O phenotypes ( 5.68 versus 5.45, p = 0.03) In multiparae blood group O was significantly associated with less frequent active placental infection ( OR 0.59, 95% CI 0.36 - 0.98, p = 0.04), and a higher newborn ponderal index compared to non- O phenotypes ( 2.65 versus 2.55, p = 0.007). In multivariate regression parity was independently associated with increased risk of placental malaria ( active andpast infection) in primiparae with blood group O ( p = 0.034) and reduced risk in multiparae with the same phenotype ( p = 0.015).
Conclusion: Parity related susceptibility to placental malaria is associated with the mothers ABO phenotype. This interaction influences foetal and placental growth and could be an important modifying factor for pregnancy outcomes. The biological explanation could relate to sialic acid dependent placental membrane differences which vary with ABO blood group
Monitoring and evaluation of malaria in pregnancy – developing a rational basis for control
Monitoring and evaluation of malaria control in pregnancy is essential for assessing the efficacy and effectiveness of health interventions aimed at reducing the major burden of this disease on women living in endemic areas. Yet there is no currently integrated strategic approach on how this should be achieved. Malaria control in pregnancy is formulated in relation to epidemiological patterns of exposure. Current emphasis is on intermittent preventive treatment (IPTp) during pregnancy with sulphadoxine-pyrimethamine in higher transmission areas, combined with insecticide treated bed nets (ITNs) and case management. Emphasis in lower transmission areas is primarily on case management. This paper discusses a rational basis for monitoring and evaluation based on: assessments of therapeutic and prophylactic drug efficacy; proportional reductions in parasite prevalence; seasonal effects; rapid assessment methodologies; birthweight and/or anaemia nomograms; case-coverage methods; maternal mortality indices; operational and programmatic indicators; and safety and pharmacovigilance of antimalarials in pregnancy. These approaches should be incorporated more effectively within National Programmes in order to facilitate surveillance and improve identification of high-risk women. Systems for utilizing routinely collected data should be strengthened, with greater attention to safety and pharmacovigilance with the advent of artemisinin combination therapies, and prospects of inadvertent exposures to artemisinins in the first trimester. Integrating monitoring activities within malaria control, reproductive health and adolescent-friendly services will be critical for implementation. Large-scale operational research is required to further evaluate the validity of currently proposed indicators, and in order to clarify the breadth and scale of implementation to be deployed
ABO phenotypes and malaria related outcomes in mothers and babies in The Gambia: a role for histo-blood groups in placental malaria?
BACKGROUND: Host susceptibility to P.falciparum is critical for understanding malaria in pregnancy, its consequences for the mother and baby, and for improving malaria control in pregnant women. Yet host genetic factors which could influence placental malaria risk are little studied and there are no reports of the role of blood group polymorphisms on pregnancy outcomes in malaria endemic areas. This study analyses the association between ABO blood group phenotypes in relation to placental malaria pathology. METHODS: A total of 198 mother/child pairs delivering in Banjul and the Kombo-St Mary District (The Gambia) were analysed. ABO blood group was measured by agglutination. Placental malaria parasites wee enumerated and the presence of malaria pigment noted. Birth anthropometry was recorded and placental weight. Maternal and infant haemoglobin was measured. RESULTS: 89 (45%) subjects were primiparae and 110 (55%)multiparae. The ABO phenotype distribution was 38(A), 52(B), 6(AB) and 102(O). Placental histo-pathology showed active placental malaria in 74 (37%), past infection in 42 (21%) and no infection in 82 cases (41%). In primiparae blood group O was associated with a higher risk of active infection (OR = 2.99; 95% CI = 1.24–7.25), and a lower risk of past infection (OR = 0.31, 0.10–1.01, p < 0.05). In multiparae the O phenotype was associated with reduced prevalence of active or past placental infection (OR = 0.45; 95% CI 0.21–0.98). The mean feto-placental weight ratio was significantly higher in multiparae with group O women compared to non-O phenotypes (5.74 vs 5.36; p = 0.04). Among primiparae with active placental infection, mean birth weight was higher in children of mothers with the O phenotype (p = 0.04). CONCLUSION: These results indicate that blood group O was significantly associated with increased placental malaria infection in primiparae and reduced risk of infection in multiparae. This parity related susceptibility was not present with other ABO phenotypes. Cell surface glycans, such as ABO and related antigens have special relevance in reproductive biology and could modulate specific cell interactions as those associated with the pathogenesis of placental malaria
Effects of long-term weekly iron and folic acid supplementation on lower genital tract infection - a double blind, randomised controlled trial in Burkina Faso
BACKGROUND:
Provision of routine iron supplements to prevent anaemia could increase the risk for lower genital tract infections as virulence of some pathogens depends on iron availability. This trial in Burkina Faso assessed whether weekly periconceptional iron supplementation increased the risk of lower genital tract infection in young non-pregnant and pregnant women.
METHODS:
Genital tract infections were assessed within a double blind, controlled, non-inferiority trial of malaria risk among nulliparous women, randomised to receive either iron and folic acid or folic acid alone, weekly, under direct observation for 18 months. Women conceiving during this period entered the pregnancy cohort. End assessment (FIN) for women remaining non-pregnant was at 18 months. For the pregnancy cohort, end assessment was at the first scheduled antenatal visit (ANC1). Infection markers included Nugent scores for abnormal flora and bacterial vaginosis (BV), T. vaginalis PCR, vaginal microbiota, reported signs and symptoms, and antibiotic and anti-fungal prescriptions. Iron biomarkers were assessed at baseline, FIN and ANC1. Analysis compared outcomes by intention to treat and in iron replete/deficient categories.
RESULTS:
A total of 1954 women (mean 16.8 years) were followed and 478 (24.5%) became pregnant. Median supplement adherence was 79% (IQR 59-90%). Baseline BV prevalence was 12.3%. At FIN and ANC1 prevalence was 12.8% and 7.0%, respectively (P < 0.011). T. vaginalis prevalence was 4.9% at FIN and 12.9% at ANC1 (P < 0.001). BV and T. vaginalis prevalence and microbiota profiles did not differ at trial end-points. Iron-supplemented non-pregnant women received more antibiotic treatments for non-genital infections (P = 0.014; mainly gastrointestinal infections (P = 0.005), anti-fungal treatments for genital infections (P = 0.014) and analgesics (P = 0.008). Weekly iron did not significantly reduce iron deficiency prevalence. At baseline, iron-deficient women were more likely to have normal vaginal flora (P = 0.016).
CONCLUSIONS:
Periconceptional weekly iron supplementation of young women did not increase the risk of lower genital tract infections but did increase general morbidity in the non-pregnant cohort. Unabsorbed gut iron due to malaria could induce enteric infections, accounting for the increased administration of antibiotics and antifungals in the iron-supplemented arm. This finding reinforces concerns about routine iron supplementation in highly malarious areas
Severe anemia in Malawian children
Background Severe anemia is a major cause of sickness and death in African children, yet the causes of anemia in this population have been inadequately studied. Methods We conducted a case-control study of 381 preschool children with severe anemia (hemoglobin concentration, <5.0 g per deciliter) and 757 preschool children without severe anemia in urban and rural settings in Malawi. Causal factors previously associated with severe anemia were studied. The data were examined by multivariate analysis and structural equation modeling. Results Bacteremia (adjusted odds ratio, 5.3; 95% confidence interval [CI], 2.6 to 10.9), malaria (adjusted odds ratio, 2.3; 95% CI, 1.6 to 3.3), hookworm (adjusted odds ratio, 4.8; 95% CI, 2.0 to 11.8), human immunodeficiency virus infection (adjusted odds ratio, 2.0; 95% CI, 1.0 to 3.8), the G6PD(sup -202/-376) genetic disorder (adjusted odds ratio, 2.4; 95% CI, 1.3 to 4.4), vitamin A deficiency (adjusted odds ratio, 2.8; 95% CI, 1.3 to 5.8), and vitamin B(sub 12) deficiency (adjusted odds ratio, 2.2; 95% CI, 1.4 to 3.6) were associated with severe anemia. Folate deficiency, sickle cell disease, and laboratory signs of an abnormal inflammatory response were uncommon. Iron deficiency was not prevalent in case patients (adjusted odds ratio, 0.37; 95% CI, 0.22 to 0.60) and was negatively associated with bacteremia. Malaria was associated with severe anemia in the urban site (with seasonal transmission) but not in the rural site (where malaria was holoendemic). Seventy-six percent of hookworm infections were found in children under 2 years of age. Conclusions There are multiple causes of severe anemia in Malawian preschool children, but folate and iron deficiencies are not prominent among them. Even in the presence of malaria parasites, additional or alternative causes of severe anemia should be considere
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