Susceptibility of <Emphasis Type="Italic">Candida</Emphasis> biofilms to histatin 5 and fluconazole

Candida-associated denture stomatitis has a high rate of recurrence. Candida biofilms formed on denture acrylic are more resistant to antifungals than planktonic yeasts. Histatins, a family of basic peptides secreted by the major salivary glands in humans, especially histatin 5, possess significant antifungal properties. We examined antifungal activities of histatin 5 against planktonic or biofilm Candida albicans and Candida glabrata. Candida biofilms were developed on poly(methyl methacrylate) discs and treated with histatin 5 (0.01–100 μM) or fluconazole (1–200 μM). The metabolic activity of the biofilms was measured by the XTT reduction assay. The fungicidal activity of histatin 5 against planktonic Candida was tested by microdilution plate assay. Biofilm and planktonic C. albicans GDH18, UTR-14 and 6122/06 were highly susceptible to histatin 5, with 50% RMA (concentration of the agent causing 50% reduction in the metabolic activity; biofilm) of 4.6 ± 2.2, 6.9 ± 3.7 and 1.7 ± 1.5 μM, and IC₅₀ (planktonic cells) of 3.0 ± 0.5, 2.6 ± 0.1 and 4.8 ± 0.5, respectively. Biofilms of C. glabrata GDH1407 and 6115/06 were less susceptible to histatin 5, with 50% RMA of 31.2 ± 4.8 and 62.5 ± 0.7 μM, respectively. Planktonic C. glabrata was insensitive to histatin 5 (IC₅₀ > 100 μM). Biofilm-associated Candida was highly resistant to fluconazole in the range 1–200 μM; e.g. at 100 μM only ~20% inhibition was observed for C. albicans, and ~30% inhibition for C. glabrata. These results indicate that histatin 5 exhibits antifungal activity against biofilms of C. albicans and C. glabrata developed on denture acrylic. C. glabrata is significantly less sensitive to histatin 5 than C. albicans.     

Conformational selection in G-proteins: lessons from Ras and Rho

The induced fit model has traditionally been invoked to describe the activating conformational change of the monomeric G-proteins, such as Ras and Rho. With this scheme, the presence or absence of the γ-phosphate of GTP leads to an instantaneous switch in conformation. Here we describe atomistic molecular simulations that demonstrate that both Ras and Rho superfamily members harbor an intrinsic susceptibility to sample multiple conformational states in the absence of nucleotide ligand. By comparing the distribution of conformers in the presence and absence of nucleotide, we show that conformational selection is the dominant mechanism by which Ras and Rho undergo nucleotide-dependent conformational changes. Furthermore, the pattern of correlated motions revealed by these simulations predicts a preserved allosteric coupling of the nucleotide-binding site with the membrane interacting C-terminus in both Rho and Ras.     

Khat Chewing and Restrictive Dietary Behaviors Are Associated with Anemia among Pregnant Women in High Prevalence Rural Communities in Eastern Ethiopia

Background

Anemia affects a high proportion of pregnant women in the developing countries. Factors associated with it vary in context. This study aimed to determine the prevalence and predictors of anemia among pregnant women in the rural eastern Ethiopia.

Methods

A community-based cross-sectional study was done on 1678 pregnant women who were selected by a cluster random sampling technique. A pregnant woman was identified as anemic if her hemoglobin concentration was <11 g/dl. Data were collected in a community-based setting. Multilevel mixed effect logistic regression was used to determine the adjusted odds ratios (AOR) with 95% confidence intervals (CI) for the predictors of anemia.

Results

Anemia was observed among 737(43.9%) of the 1678 pregnant women studied (95% CI 41.5%–46.3%). After controlling for the confounders, the risk of anemia was 29% higher in the women who chewed khat daily than those who sometimes or never did so (AOR, 1.29; 95% CI, 1.02–1.62). The study subjects with restrictive dietary behavior (reduced either meal size or frequency) had a 39% higher risk of anemia compared to those without restrictive dietary behavior (AOR, 1.39; 95% CI, 1.02–1.88). The risk of anemia was increased by 68% (AOR, 1.68; 95% CI, 1.15–2.47), and 60% (AOR, 1.60; 95% CI, 1.08–2.37) in parity levels of 2 births and 3 births, respectively. Compared to the first trimester, the risk of anemia was higher by two-fold (AOR, 2.09; 95% CI, 1.46–3.00) in the second trimester and by four-fold (AOR, 4.23; 95% CI, 2.97–6.02) in the third trimester.

Conclusion

In this study, two out of five women were anemic. Chewing khat and restrictive dietary habits that are associated with anemia in the setting should be addressed through public education programs. Interventions should also focus on the women at higher parity levels and those who are in advanced stages of pregnancy.     

Household Water Chlorination Reduces Incidence of Diarrhea among Under-Five Children in Rural Ethiopia: A Cluster Randomized Controlled Trial

Background

Household water treatment has been advocated as a means of decreasing the burden of diarrheal diseases among young children in areas where piped and treated water is not available. However, its effect size, the target population that benefit from the intervention, and its acceptability especially in rural population is yet to be determined. The objective of the study was to assess the effectiveness of household water chlorination in reducing incidence of diarrhea among children under-five years of age.

Method

A cluster randomized community trial was conducted in 36 rural neighborhoods of Eastern Ethiopia. Households with at least one child under-five years of age were included in the study. The study compared diarrhea incidence among children who received sodium hypochlorite (liquid bleach) for household water treatment and children who did not receive the water treatment. Generalized Estimation Equation model was used to compute adjusted incidence rate ratio and the corresponding 95% confidence interval.

Result

In this study, the incidence of diarrhea was 4.5 episodes/100 person week observations in the intervention arm compared to 10.4 episodes/100 person week observations in the control arm. A statistically significant reduction in incidence of diarrhea was observed in the intervention group compared to the control (Adjusted IRR = 0.42, 95% CI 0.36–0.48).

Conclusion

Expanding access to household water chlorination can help to substantially reduce child morbidity and achieve millennium development goal until reliable access to safe water is achieved.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01376440","term_id":"NCT01376440"}}NCT01376440     

Death and Seeking Alternative Therapy Largely Accounted for Lost to Follow-up of Patients on ART in Northwest Ethiopia: A Community Tracking Survey

Background

Antiretroviral treatment programs in sub-Saharan African countries are highly affected by LTF. Tracking patients lost to follow-up and understanding their status is essential to maintain program quality and to develop targeted interventions to prevent LTF. We aimed to determine the outcome and factors associated with LTF.

Method

A lost to follow-up community tracking survey was conducted to determine the reasons, outcomes and factors associated with LTF at the University of Gondar Hospital, northwest Ethiopia. All patients were tracked at home to ascertain outcome status for lost to follow-up (death and non-death losses).

Result

Out of the 551 patients LTF, 486 (88.20%) were successfully tracked. Death was the most common reason accounted for 233 (47.94%) of the lost to follow-up. Reasons for non-deaths losses include: stopped antiretroviral treatment due to different reasons, 135(53.36%), and relocation to another antiretroviral treatment program by self- transfer, 118(46.64%). The rate of mortality in the first six months was 72.12 per 100 person-years (95% CI: 61.80–84.24) but this sharply decreased after 12 months to 7.92 per 100 person-years (95% CI: 4.44–14.41). Baseline clinical characteristics were strongly associated with mortality.

Conclusion

Death accounts for about half of the loss to follow up. Most deaths occur in the first six months of loss. Seeking alternative therapy is another major reason for loss to follow up. Early tracking mechanisms are necessary to prevent death.     

Aggregation of Lipid-Anchored Full-Length H-Ras in Lipid Bilayers: Simulations with the MARTINI Force Field

Lipid-anchored Ras oncoproteins assemble into transient, nano-sized substructures on the plasma membrane. These substructures, called nanoclusters, were proposed to be crucial for high-fidelity signal transmission in cells. However, the molecular basis of Ras nanoclustering is poorly understood. In this work, we used coarse-grained (CG) molecular dynamics simulations to investigate the molecular mechanism by which full-length H-ras proteins form nanoclusters in a model membrane. We chose two different conformations of H-ras that were proposed to represent the active and inactive state of the protein, and a domain-forming model bilayer made up of di16:0-PC (DPPC), di18:2-PC (DLiPC) and cholesterol. We found that, irrespective of the initial conformation, Ras molecules assembled into a single large aggregate. However, the two binding modes, which are characterized by the different orientation of the G-domain with respect to the membrane, differ in dynamics and organization during and after aggregation. Some of these differences involve regions of Ras that are important for effector/modulator binding, which may partly explain observed differences in the ability of active and inactive H-ras nanoclusters to recruit effectors. The simulations also revealed some limitations in the CG force field to study protein assembly in solution, which we discuss in the context of proposed potential avenues of improvement.     

Effect of Brassica carinata (L.) biofumigants (seed meal) on chickpea wilt (Fusarium oxysporum f.sp. ciceris), growth,yield and yield component in Ethiopia

Pot experiments were carried out in the green house at Amhara Regional Agriculture Research Institute (ARARI) Bahirdar, Ethiopia to evaluate the potential of Brassica carinata cultivars namely; Holleta-l, S-67 and Yellow Dodola in 2007 and 2008. The treatment effects of B. carinata (L.) cultivars Holleta–1, S-67 and Yellow Dodola seed meals on chickpea fusarium wilt (Fusarium oxysporum f.sp. ciceris) were studied. Six rates of seed (0, 5, 10, 15, 20 and 25 g/kg of infested soil) were used. Infested soil without B.carinata cultivars amendments as a control and susceptible check variety JG-62 also without amendments were used in all the experiments. For each seed meal experiment, the treatments were arranged in factorial randomised complete block design in three replications. Data on seedling emergence, wilt incidence, fresh weight, dry weight, pod per plant, seed per pod, hundred seed weight and yield per hectare were collected. The amendments of infested soil with B.carinata cultivars seed meal reduced the incidence of chickpea fusarium wilt and increased yield per hectare. The interaction of the seed meal Holleta-1, S-67 and Yellow Dodola at 10–25 g/kg infested soil were effective in reducing wilt incidences on chickpea. However, the interaction of Yellow Dodola with 20 and 25 g seed meal per kg infested soil were the best combination in reducing significantly wilt incidence. The three cultivars incorporated at different level of doses significantly affected the influence of Fusarium wilt on the fresh weight, dry weight, pod per plant, seed per pod, hundred seed weight and yield per hectare. The highest yield kg/ha was recorded in combination of Yellow Dodola seed meal at 20 and 25 g followed by S-67 and Holleta-1 at 25 g /kg infested soil, respectively. The interaction of Holleta-1 at 5–25 infested soil significantly reduced disease incidence up to 16.7–43.3% and increased yield per hectare with mean by (30%) over the control. Seed meal amendment S-67 significantly reduce disease incidence 26.7–46.7% and increased yield kg/ha with mean by (36.7%) from the unamended control. Yellow dodola reduces disease incidence with 26.7–63.3% and increased yield kg/ha with mean by (45%) from the unamended control. The result indicates the potential of using Brassica crop seed meal amendment as useful component of integrated chickpea wilt management.     

Children with Moderate Acute Malnutrition with No Access to Supplementary Feeding Programmes Experience High Rates of Deterioration and No Improvement: Results from a Prospective Cohort Study in Rural Ethiopia

BackgroundChildren with moderate acute malnutrition (MAM) have an increased risk of mortality, infections and impaired physical and cognitive development compared to well-nourished children. In parts of Ethiopia not considered chronically food insecure there are no supplementary feeding programmes (SFPs) for treating MAM. The short-term outcomes of children who have MAM in such areas are not currently described, and there remains an urgent need for evidence-based policy recommendations.MethodsWe defined MAM as mid-upper arm circumference (MUAC) of ≥11.0cm and <12.5cm with no bilateral pitting oedema to include Ethiopian government and World Health Organisation cut-offs. We prospectively surveyed 884 children aged 6–59 months living with MAM in a rural area of Ethiopia not eligible for a supplementary feeding programme. Weekly home visits were made for seven months (28 weeks), covering the end of peak malnutrition through to the post-harvest period (the most food secure window), collecting anthropometric, socio-demographic and food security data.ResultsBy the end of the study follow up, 32.5% (287/884) remained with MAM, 9.3% (82/884) experienced at least one episode of SAM (MUAC <11cm and/or bilateral pitting oedema), and 0.9% (8/884) died. Only 54.2% of the children recovered with no episode of SAM by the end of the study. Of those who developed SAM half still had MAM at the end of the follow up period. The median (interquartile range) time to recovery was 9 (4–15) weeks. Children with the lowest MUAC at enrolment had a significantly higher risk of remaining with MAM and a lower chance of recovering.ConclusionsChildren with MAM during the post-harvest season in an area not eligible for SFP experience an extremely high incidence of SAM and a low recovery rate. Not having a targeted nutrition-specific intervention to address MAM in this context places children with MAM at excessive risk of adverse outcomes. Further preventive and curative approaches should urgently be considered.     

GeneXpert MTB/RIF Assay for the Diagnosis of Tuberculous Lymphadenitis on Concentrated Fine Needle Aspirates in High Tuberculosis Burden Settings

Introduction

The diagnosis of tuberculous lymphadenitis (TBL) remains challenging. The routinely used methods (cytology and smear microscopy) have sub-optimal sensitivity. Recently, WHO recommends GeneXpert to be used as the initial diagnostic test in patients suspected of having extra-pulmonary tuberculosis (EPTB). However, this was a conditional recommendation due to very low-quality evidence available and more studies are needed. In this study we evaluated the performance of Xpert for the diagnosis of TBL on concentrated fine needle aspirates (FNA) in Southwest Ethiopia.

Methods

FNA was collected from presumptive TBL cases. Two smears were prepared from each aspirate and processed for cytology and conventional microscopy. The remaining aspirate was treated with N-acetyl-L-cysteine-NaOH and centrifuged for 15minutes at 3000g. The concentrated sediment was used for culture and Xpert test. Capilia TB-Neo test was used to differentiate M. tuberculosis complex (MTBC) from non-tuberculous mycobacteria (NTM). Composite bacteriological methods (culture and/or smear microscopy) were considered as a reference standard.

Result

Out of 143 enrolled suspects, 64.3% (92/143) were confirmed TBL cases by the composite reference standard (CRS). Xpert detected M. tuberculosis complex (MTBC) in 60.1% (86/143) of the presumptive TBL cases. The sensitivity of Xpert compared to CRS was 87.8% [95% CI: 81.0–94.5] and specificity 91.1% [95% CI: 82.8–99.4]. The sensitivity was 27.8% for smear microscopy and 80% for cytology compared to CRS. Cytology showed the lowest specificity (57.8%). Xpert was positive in 4 out of 45 culture- and smear-negative cases. Among 47 cytomorphologically non-TBL cases, 15 were positive on Xpert. More than half of Xpert-positive cases were in the range of very low cut-off threshold values (28<Ct<38). Resistance to rifampicin was identified in 4.7% (4/86) of Xpert-positive cases.

Conclusion

Xpert test showed a high sensitivity and specificity for the diagnosis of TBL on concentrated FNA samples. In addition, Xpert offered rapid detection of rifampicin-resistant M. tuberculosis strains from lymph node aspirates.     

Anemia among Primary School Children in Eastern Ethiopia

Background

Anemia during childhood impairs physical growth, cognitive development and school performance. Identifying the causes of anemia in specific contexts can help efforts to prevent negative consequences of anemia among children. The objective of this study was to assess prevalence and identify correlates of anemia among school children in Eastern Ethiopia.

Methods

A cross sectional study was conducted from January 2012 to February 2012 in Kersa, Eastern Ethiopia. The study included randomly selected primary school students. Hemoglobin concentration was measured using a Hemocue haemoglobinometer. A child was identified as anemic if the hemoglobin concentration was <11.5 g/dl for children (5–11 yrs) and < 12 g/dl for child older than 12 years age. Poisson regression model with robust variance was used to calculate prevalence ratios.

Result

The overall prevalence of anemia was 27.1% (95% CI: 24.98, 29.14): 13.8% had mild, 10.8% moderate, and 2.3% severe anemia. Children with in the age group of 5-9 years (APR, 1.083; 95% CI, 1.044- 1.124) were at higher risk for anemia. Paternal education (Illiterate, 1.109; 1.044 - 1.178) was positively associated with anemia. Children who had irregular legume consumption (APR, 1.069; 95% CI, 1.022 -1.118) were at higher risk for anemia.

Conclusion

About a quarter of school children suffer from anemia and their educational potential is likely to be affected especially for those with moderate and severe anemia. Child age, irregular legume consumption, and low paternal schooling were associated with anemia. Intervention programmes aimed to reduce anemia among school children are crucial to ensure proper growth and development of children.