Nodding syndrome in Mundri county,South Sudan: environmental,nutritional and infectious factors

Background

Nodding Syndrome is a seizure disorder of children in Mundri County, Western Equatoria, South Sudan. The disorder is reported to be spreading in South Sudan and northern Uganda.

Objective

To describe environmental, nutritional, infectious, and other factors that existed before and during the de novo 1991 appearance and subsequent increase in cases through 2001.

Methods

Household surveys, informant interviews, and case-control studies conducted in Lui town and Amadi village in 2001–2002 were supplemented in 2012 by informant interviews in Lui and Juba, South Sudan.

Results

Nodding Syndrome was associated with Onchocerca volvulus and Mansonella perstans infections, with food use of a variety of sorghum (serena) introduced as part of an emergency relief program, and was inversely associated with a history of measles infection. There was no evidence to suggest exposure to a manmade neurotoxic pollutant or chemical agent, other than chemically dressed seed intended for planting but used for food. Food use of cyanogenic plants was documented, and exposure to fungal contaminants could not be excluded.

Conclusion

Nodding Syndrome in South Sudan has an unknown etiology. Further research is recommended on the association of Nodding Syndrome with onchocerciasis/mansonelliasis and neurotoxins in plant materials used for food.     

Hepatitis C and blood transfusion among children attending the Sickle Cell Clinic at Mulago Hospital,Uganda

Background

Hepatitis C virus (HCV) accounts for 90% of post-transfusion hepatitis. In Uganda, there has been limited research of prevalence of HCV among sickle cell anaemia (SS) patients, a group at risk for multiple transfusions.

Objectives

To establish prevalence of HCV infection and determine whether blood transfusion increases risk among SS patients.

Methods

244 SS patients aged 1–18 years were recruited by consecutive sampling. Socio-demographic, clinical and transfusion history was collected. Clinical examination done and blood tested for HCV by MEIA.

Results

244 children were recruited. Of these, 159 (65%) had a history of blood transfusion. Among the transfused, five patients were HCV positive. Four of these were over 12 years of age. Among patients with no history of transfusion, one patient aged 14 years was HCV positive. Risk of HCV was higher among the transfused OR 2.7(CI 0.31–24). Patients who received more than two units were more likely to be HCV positive (p=0.03).

Conclusions

HCV prevalence of 2.5% was low but higher than that reported by other investigators in Uganda. Blood transfusion was a major contributing factor in occurrence of HCV. Children who get repeated transfusions should be screened for Hepatitis C and screening of blood for HCV prior to transfusion would help reduce occurrence of the disease.     

The Association Between Physical Activity and Maternal Sleep During the Postpartum Period

Physical activity is associated with improved sleep quality and duration in the general population, but its effect on sleep in postpartum women is unknown. We examined cross-sectional and longitudinal associations between hours/week of self-reported domain-specific and overall moderate to vigorous physical activity (MVPA) and sleep quality and duration at 3- and 12-months postpartum among a cohort of 530 women in the Pregnancy, Infection, and Nutrition Postpartum Study. MVPA was not associated with sleep quality or duration at 3-months postpartum. At 12-months postpartum, a 1 h/week increase in recreational MVPA was associated with higher odds of good (vs. poor) sleep quality (odds ratio, OR 1.14; 95 % confidence interval, CI, 1.03–1.27) and a 1 h/week increase in child/adult care MVPA was associated with lower odds of good (vs. poor) sleep quality (OR = 0.93; 95 % CI 0.88–0.99). A 1 h/week increase in child/adult care MVPA (OR 1.08, 95 % CI 1.00–1.16) was associated with higher odds of long sleep duration and 1 h/week increases in indoor household (OR 1.09, 95 % CI 1.01–1.18) and overall MVPA (OR 1.04, 95 % CI 1.01–1.07) were associated with higher odds of short (vs. normal) sleep duration. Comparing 3-months postpartum to 12-months postpartum, increased work MVPA was associated with good sleep quality (OR 2.40, 95 % CI 1.12–5.15) and increased indoor household MVPA was associated with short sleep duration (OR 1.85, 95 % CI 1.05–3.27) as measured at 12-months postpartum. Selected domains of MVPA and their longitudinal increases were associated with sleep quality and duration at 12-months postpartum. Additional research is needed to elucidate whether physical activity can improve postpartum sleep.     

Examining the Impact of the Walking School Bus With an Agent-Based Model

We used an agent-based model to examine the impact of the walking school bus (WSB) on children’s active travel to school. We identified a synergistic effect of the WSB with other intervention components such as an educational campaign designed to improve attitudes toward active travel to school. Results suggest that to maximize active travel to school, children should arrive on time at “bus stops” to allow faster WSB walking speeds. We also illustrate how an agent-based model can be used to identify the location of routes maximizing the effects of the WSB on active travel. Agent-based models can be used to examine plausible effects of the WSB on active travel to school under various conditions and to identify ways of implementing the WSB that maximize its effectiveness.Active travel to school (ATS) is of special significance to children’s physical and mental health and has important implications for the environment and sustainable development.1,2 Today, fewer than 15% of US children and adolescents walk or bicycle to school, compared with approximately 50% half a century ago.3 Multiple factors are associated with ATS, including characteristics of children and families as well as features of schools and neighborhoods.1,4Existing interventions designed to promote ATS are heterogeneous in terms of size, scope, and focus,5–7 and according to a recent systematic review,8 most have shown limited effectiveness in promoting ATS. Interventions targeting schools, parents, and communities and those geared toward a specific goal tend to be more effective than those that are broader in focus. The ability to evaluate an intervention’s impact has often been limited by methodological issues such as lack of an experimental study design and limitations in the validity and reliability of the measures used. The complexity of the factors influencing ATS and the fact that the effects of these factors may vary from context to context further limit the utility of both observational and experimental studies in evaluating the long-term impact of various interventions.One notable example of an intervention to increase ATS is the walking school bus (WSB).9 The WSB is a program in which children walk to school in groups led by adults along a planned route with designated meeting places (i.e., “bus stops”) where other children join in. The primary goal is to allow children to actively and safely commute to school. During the 2009–2010 school year, about 6.2% of the elementary schools in the United States organized a WSB.10 Although most WSBs have shown promising short-term benefits,7,11–15 evidence of their effectiveness over long periods is limited.A major challenge in evaluating the impact of interventions such as the WSB is that it is difficult to evaluate how the intervention may interact with features of the context in which it is implemented or how features of the intervention may influence its effectiveness. For example, the effects of ATS may be modified by educational campaigns targeted at increasing favorable attitudes toward walking among children.Various features related to how the WSB is implemented may also influence its effectiveness. When using the WSB, children may take longer to arrive at school because of the waiting time at the “bus stop,” the group’s decreased walking speed, and detours that need to be taken for the child to reach the WSB route. If children arrive at the stop earlier (increasing their waiting times), group walking speed can increase (because the group is less likely to wait at each stop for other children to join in), reducing the total travel time. The challenge is to find the strategy that minimizes waiting time while maximizing walking speed.Another challenge for the WSB is the selection of bus routes and stops. More bus routes may attract more children to join the WSB but may also necessitate more adult involvement. It is therefore important to identify the most beneficial placement of a limited number of bus routes. To our knowledge, there is scant information on how these contextual or implementation factors could affect the impact of the WSB on children’s active travel to school.A large body of work has recommended multilevel interventions (i.e., interventions that combine environmental and individual-level elements) for behavioral change because of possible synergistic effects.16–20 It has been noted that evidence on interventions derived from randomized trials is often limited because the impact of context as a modifier cannot be investigated. For example, it is well established that physical activity is influenced by the interplay between environmental and psychological factors.21,22 Yet, existing observational or experimental studies are ill suited to investigate these interactions. Modeling or simulation studies can be important sources of complementary evidence on how the impact of interventions such as the WSB may be affected by various contextual factors.In public health, there has been growing interest in using complex systems modeling as a complement to observational studies and randomized trials to better understand the plausible impact of interventions or policies in different contexts.23–25 The tools of complex systems models allow researchers to evaluate the effects of interventions while accounting for dependencies and feedbacks, which are not easily captured in standard statistical analyses. One such tool is agent-based modeling. Agent-based models (ABMs) are computational models that can be used to simulate the actions and interactions of agents as well as the dynamic interactions between agents and their environments to gain an understanding of the functioning of a system.26,27 ABMs have increasingly been used to investigate how the social and built environments shape people’s travel behavior.28–32We previously developed an ABM31 to simulate children’s ATS within a hypothetical city. The model was used to explore the plausible implications of policies targeting 2 established barriers to ATS: long distance to school and traffic safety. In this study, we extended the model to examine the potential effects of the WSB on ATS. Specifically, we examined whether the effects of the WSB are enhanced by an educational campaign aimed at improving attitudes toward ATS among children, how changing the walking speed of the WSB and the waiting time for children at the WSB stops affects ATS, and the impact of different bus route placements. All 3 issues are important in the design and implementation of the WSB but are difficult to assess in experimental or observational studies. Because previous work suggested that ATS is influenced by population density,31 we investigated the 3 issues across various levels of population density.     

Automatic wide complex tachycardia differentiation using mathematically synthesized vectorcardiogram signals

BackgroundAutomated wide complex tachycardia (WCT) differentiation into ventricular tachycardia (VT) and supraventricular wide complex tachycardia (SWCT) may be accomplished using novel calculations that quantify the extent of mean electrical vector changes between the WCT and baseline electrocardiogram (ECG). At present, it is unknown whether quantifying mean electrical vector changes within three orthogonal vectorcardiogram (VCG) leads (X, Y, and Z leads) can improve automated VT and SWCT classification.MethodsA derivation cohort of paired WCT and baseline ECGs was used to derive five logistic regression models: (i) one novel WCT differentiation model (i.e., VCG Model), (ii) three previously developed WCT differentiation models (i.e., WCT Formula, VT Prediction Model, and WCT Formula II), and (iii) one “all‐inclusive” model (i.e., Hybrid Model). A separate validation cohort of paired WCT and baseline ECGs was used to trial and compare each model''s performance.ResultsThe VCG Model, composed of WCT QRS duration, baseline QRS duration, absolute change in QRS duration, X‐lead QRS amplitude change, Y‐lead QRS amplitude change, and Z‐lead QRS amplitude change, demonstrated effective WCT differentiation (area under the curve [AUC] 0.94) for the derivation cohort. For the validation cohort, the diagnostic performance of the VCG Model (AUC 0.94) was similar to that achieved by the WCT Formula (AUC 0.95), VT Prediction Model (AUC 0.91), WCT Formula II (AUC 0.94), and Hybrid Model (AUC 0.95).ConclusionCustom calculations derived from mathematically synthesized VCG signals may be used to formulate an effective means to differentiate WCTs automatically.     

Ability of laypersons to use the cincinnati prehospital stroke scale

Objective

Early stroke recognition optimizes patients' opportunities to benefit from therapeutic options. Prehospital stroke recognition is suboptimal. If 9-1-1 dispatchers used stroke-identification tools, prehospital stroke recognition might occur more rapidly and accurately. The Cincinnati Prehospital Stroke Scale (CPSS) is a brief, effective tool used by emergency medical services and hospital personnel to identify stroke. The study's goal was to determine whether laypersons could be instructed to use the CPSS over the telephone.

Methods

Adult visitors (laypersons) to a tertiary care emergency department were enrolled. Using a mock patient, laypersons were instructed to use the CPSS via telephone by an investigator simulating a 9-1-1 dispatcher. The patient randomly portrayed clinically normal and abnormal patient types. The layperson's ability to convey CPSS instructions to the patient and relay findings to the investigator was scored.

Results

Seventy laypersons were enrolled (35 each for normal and abnormal patient types). Average age was 48 years, 63% were female, and 40% never attended college. Facial droop and speech instructions were administered with 100% accuracy. Arm drift instructions were administered with 99% accuracy. Layperson accuracies for interpreting findings were 93% for facial droop, 93% for arm drift, and 97% for speech. Overall, stroke symptoms were detected with 94% sensitivity (95% CI 87, 100) and 83% specificity (95% CI 70, 95).

Conclusion

Laypersons correctly administered and interpreted the CPSS when directed to do so over the telephone by a trained investigator. These findings suggest that the CPSS may be a useful tool in early prehospital detection of stroke by dispatchers.     

Modulation of in vitro eosinophil progenitors by hydrocortisone: role of accessory cells and interleukins

The growth of human eosinophil progenitors (CFU-Eo) and the modulation of growth by hydrocortisone were studied as functions of the presence of lymphocytes and monocytes in marrow cells under study; and the source of colony-stimulating factors, specifically, media conditioned by macrophage-like cell line, GCT; phytohemagglutinin-stimulated mononuclear cells (PHA-LCM); or the T cell line, MO. CFU-Eo growth was greatest in marrow containing accessory cells as compared to marrow depleted of accessory cells; and in marrow treated with phytohemagglutinin-stimulated leukocyte conditioned media (PHA-LCM) or MO (T cell line)-conditioned medium (MO-CM) as compared with GCT cell- conditioned medium (GCT-CM). Hydrocortisone reproducibly inhibited eosinophil progenitor growth in unfractionated marrow stimulated by GCT- CM. This effect was abrogated by admixing irradiated mononuclear cells or T lymphocytes with the target marrow or by adding interleukin 1 or interleukin 2 (IL-1, IL-2). Inhibition by hydrocortisone did not occur when monocyte and T lymphocyte depleted marrow was studied. Unlike GCT- CM, MO-CM and PHA-LCM stimulated equal proportions of eosinophil progenitors in nondepleted and accessory cell-depleted marrow and demonstrated less hydrocortisone inhibition. However, both GCT-CM and PHA-LCM produced in the presence of hydrocortisone stimulated significantly fewer CFU-Eos in both unfractionated and accessory cell- depleted marrow target populations. These results indicate that the growth of CFU-Eo and inhibition of growth by hydrocortisone is a direct function of a monocyte-T cell interaction and probably is mediated through effects on the production/release of eosinophil colony stimulating factor (Eo-CSF).     

超声和微泡造影剂介导细胞基因转染的实验研究

目的 探讨低频超声对细胞基因转染的作用。方法 超声治疗仪频率1MHz，脉冲重复频率100Hz，占空系数20％。质粒DNA为含编码绿荧光蛋白的pEGFP。应用荧光显微镜和流式细胞仪评价细胞基因转染率，台盼蓝染色计算细胞成活率。选用C2C12、3T3-MDEI和CHO3种细胞系为研究对象，加入DNA后辐照不同声强、时间或加入超声造影剂，观察各条件下的细胞基因转染率和成活率。结果 ①超声介导的基因转染与声强和辐射时间有关，最佳剂量为1w／cm^2 20s；②同样超声剂量，较高的声强较早达到最大基因转染率；③较低剂量时，微泡造影剂可使超声介导的基因转染提高2～3倍并可显著提高最高基因转染率。结论 低频超声可介导细胞基因转染，基因转染率不但与超声辐射剂量有关，而且同样剂量时，高声强较早达到最大基因转染率，最佳剂量是1w／cm^2 20s。同时，微泡造影剂可提高超声介导基因转染的最高转染率。