2,368 research outputs found

    Aflatoxins and fumonisins contamination of home-made food (Weanimix) from cereal-legume blends for children

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    Background: Weanimix is an important food for children in Ghana. Mothers are trained to prepare homemade weanimix from beans, groundnuts and  maize for their infants. Groundnuts and maize are prone to aflatoxincontamination while fumonisin contaminates maize. Aflatoxin, is produced by the Asperguillus fungi while fumonisin, is produced by Fusarium fungi. These mycotoxins occur in tropical areas worldwide due to favorable climate for their growth.Objective: The objective of the study was to determine the levels of aflatoxin and fumonisin in homemade weanimix in the Ejura-Sekyedumase district in the Ashanti Region of Ghana.Methods: Thirty six homemade weanimix samples (50g each) were collected from households. Aflatoxin and fumonisin were measured using a fluorometric procedure described by the Association of Official AnalyticalChemist (AOAC official method 993.31, V1 series 4).Results: Aflatoxin and fumonisin were detected in all 36 samples, range 7.9-500ppb. Fumonisin levels range: 0.74-11.0ppm). Thirty (83.3%) of the thirty six samples were over the action limit of 20ppb for aflatoxin withan overall mean of 145.2 ppb whiles 58.3% of the samples had fumonisins above the action limit of 4 ppm with an overall mean of 4.7 ppm .Conclusion: There were significant aflatoxin and fumonisin contamination of homemade weanimix. Children fed on this nutritional food were being exposed to unacceptable levels of aflatoxin and fumonisin. Therefore there is a critical need to educate mothers on the dangers of mycotoxin exposure and to develop strategies to eliminate exposure of children fedhomemade weanimix to aflatoxin and fumonisin.Keywords: Aflatoxin, Fumonisin, Home-made Weanimix, infants

    A comparison of liquid and solid culture for determining relapse and durable cure in phase III TB trials for new regimens

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    BACKGROUND: Tuberculosis kills more people than any other infectious disease, and new regimens are essential. The primary endpoint for confirmatory phase III trials for new regimens is a composite outcome that includes bacteriological treatment failure and relapse. Culture methodology is critical to the primary trial outcome. Patients in clinical trials can have positive cultures after treatment ends that may not necessarily indicate relapse, which was ascribed previously to laboratory cross-contamination or breakdown of old lesions. Löwenstein-Jensen (LJ) medium was the previous standard in clinical trials, but almost all current and future trials will use the Mycobacteria Growth Indicator Tube (MGIT) system due to its simplicity and consistency of use, which will affect phase III trial results. LJ was used for the definition of the primary endpoint in the REMoxTB trial, but every culture was also inoculated in parallel into the MGIT system. The data from this trial, therefore, provide a unique opportunity to investigate and compare the incidence of false 'isolated positives' in liquid and solid media and their potential impact on the primary efficacy results. METHODS: All post-treatment positive cultures were reviewed in the REMoxTB clinical trial. Logistic regression models were used to model the incidence of isolated positive cultures on MGIT and LJ. RESULTS: A total of 12,209 sputum samples were available from 1652 patients; cultures were more often positive on MGIT than LJ. In 1322 patients with a favourable trial outcome, 126 (9.5%) had cultures that were positive in MGIT compared to 34 (2.6%) patients with positive cultures on LJ. Among patients with a favourable outcome, the incidence of isolated positives on MGIT differed by study laboratory (p < 0.0001) with 21.9% of these coming from one laboratory investigating only 4.9% of patients. No other baseline factors predicted isolated positives on MGIT after adjusting for laboratory. There was evidence of clustering of isolated positive cultures in some patients even after adjusting for laboratory, p < 0.0001. The incidence of isolated positives on MGIT did not differ by treatment arm (p = 0.845, unadjusted). Compared to negative MGIT cultures, positive MGIT cultures were more likely to be associated with higher grade TB symptoms reported within 7 days either side of sputum collection in patients with an unfavourable primary outcome (p < 0.0001) but not in patients with a favourable outcome (p = 0.481). CONCLUSIONS: Laboratory cross-contamination was a likely cause of isolated positive MGIT cultures which were clustered in some laboratories. Certain patients had repeated positive MGIT cultures that did not meet the definition of a relapse. This pattern was too common to be explained by cross-contamination only, suggesting that host factors were also responsible. We conclude that MGIT can replace LJ in phase III TB trials, but there are implications for the definition of the primary outcome and patient management in trials in such settings. Most importantly, the methodologies differ in the incidence of isolated positives and in their capacity for capturing non-tuberculosis mycobacteria. It emphasises the importance of effective medical monitoring after treatment ends and consideration of clinical signs and symptoms for determining treatment failure and relapse

    Contribution of anadromous fish to the diet of European catfish in a large river system

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    Many anadromous fish species, when migrating from the sea to spawn in fresh waters, can potentially be a valuable prey for larger predatory fish, thereby efficiently linking these two ecosystems. Here, we assess the contribution of anadromous fish to the diet of European catfish (Silurus glanis) in a large river system (Garonne, southwestern France) using stable isotope analysis and allis shad (Alosa alosa) as an example of anadromous fish. Allis shad caught in the Garonne had a very distinct marine delta(13)C value, over 8 per thousand higher after lipid extraction compared to the mean delta(13)C value of all other potential freshwater prey fish. The delta(13)C values of European catfish varied considerably between these two extremes and some individuals were clearly specializing on freshwater prey, whereas others specialized on anadromous fish. The mean contribution of anadromous fish to the entire European catfish population was estimated to be between 53% and 65%, depending on the fractionation factor used for delta(13)C

    Fluoroquinolones and isoniazid-resistant tuberculosis: implications for the 2018 WHO guidance.

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    INTRODUCTION: 2018 World Health Organization (WHO) guidelines for the treatment of isoniazid (H)-resistant (Hr) tuberculosis recommend a four-drug regimen: rifampicin (R), ethambutol (E), pyrazinamide (Z) and levofloxacin (Lfx), with or without H ([H]RZE-Lfx). This is used once Hr is known, such that patients complete 6 months of Lfx (≄6[H]RZE-6Lfx). This cohort study assessed the impact of fluoroquinolones (Fq) on treatment effectiveness, accounting for Hr mutations and degree of phenotypic resistance. METHODS: This was a retrospective cohort study of 626 Hr tuberculosis patients notified in London, 2009-2013. Regimens were described and logistic regression undertaken of the association between regimen and negative regimen-specific outcomes (broadly, death due to tuberculosis, treatment failure or disease recurrence). RESULTS: Of 594 individuals with regimen information, 330 (55.6%) were treated with (H)RfZE (Rf=rifamycins) and 211 (35.5%) with (H)RfZE-Fq. The median overall treatment period was 11.9 months and median Z duration 2.1 months. In a univariable logistic regression model comparing (H)RfZE with and without Fqs, there was no difference in the odds of a negative regimen-specific outcome (baseline (H)RfZE, cluster-specific odds ratio 1.05 (95% CI 0.60-1.82), p=0.87; cluster NHS trust). Results varied minimally in a multivariable model. This odds ratio dropped (0.57, 95% CI 0.14-2.28) when Hr genotype was included, but this analysis lacked power (p=0.42). CONCLUSIONS: In a high-income setting, we found a 12-month (H)RfZE regimen with a short Z duration to be similarly effective for Hr tuberculosis with or without a Fq. This regimen may result in fewer adverse events than the WHO recommendations

    Spot sputum samples are at least as good as early morning samples for identifying Mycobacterium tuberculosis

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    Background The use of early morning sputum samples (EMS) to diagnose tuberculosis (TB) can result in treatment delay given the need for the patient to return to the clinic with the EMS, increasing the chance of patients being lost during their diagnostic workup. However, there is little evidence to support the superiority of EMS over spot sputum samples. In this new analysis of the REMoxTB study, we compare the diagnostic accuracy of EMS with spot samples for identifying Mycobacterium tuberculosis pre- and post-treatment. Methods Patients who were smear positive at screening were enrolled into the study. Paired sputum samples (one EMS and one spot) were collected at each trial visit pre- and post-treatment. Microscopy and culture on solid LJ and liquid MGIT media were performed on all samples; those missing corresponding paired results were excluded from the analyses. Results Data from 1115 pre- and 2995 post-treatment paired samples from 1931 patients enrolled in the REMoxTB study were analysed. Patients were recruited from South Africa (47%), East Africa (21%), India (20%), Asia (11%), and North America (1%); 70% were male, median age 31 years (IQR 24–41), 139 (7%) co-infected with HIV with a median CD4 cell count of 399 cells/ÎŒL (IQR 318–535). Pre-treatment spot samples had a higher yield of positive Ziehl–Neelsen smears (98% vs. 97%, P = 0.02) and LJ cultures (87% vs. 82%, P = 0.006) than EMS, but there was no difference for positivity by MGIT (93% vs. 95%, P = 0.18). Contaminated and false-positive MGIT were found more often with EMS rather than spot samples. Surprisingly, pre-treatment EMS had a higher smear grading and shorter time-to-positivity, by 1 day, than spot samples in MGIT culture (4.5 vs. 5.5 days, P < 0.001). There were no differences in time to positivity in pre-treatment LJ culture, or in post-treatment MGIT or LJ cultures. Comparing EMS and spot samples in those with unfavourable outcomes, there were no differences in smear or culture results, and positive results were not detected earlier in Kaplan–Meier analyses in either EMS or spot samples. Conclusions Our data do not support the hypothesis that EMS samples are superior to spot sputum samples in a clinical trial of patients with smear positive pulmonary TB. Observed small differences in mycobacterial burden are of uncertain significance and EMS samples do not detect post-treatment positives any sooner than spot samples

    Band gap temperature-dependence of close-space sublimation grown Sb2Se3 by photo-reflectance

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    The candidate photovoltaic absorber antimony selenide Sb2Se3 has been prepared by the commercially attractive close-space sublimation method. Structure, composition, and morphology are studied by x-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. Large rhubarb-like grains favorable for photovoltaics naturally develop. The temperature-dependence of the direct band gap is determined by photoreflectance between 20 and 320 K and is well described by the Varshni and Bose–Einstein relations, blue-shifting with decreasing temperature from 1.18 to 1.32 eV. The 300 K band gap matches that seen in high quality single-crystal material, while the 0 K gap is consistent with that found in first-principles calculations, further supporting the array of beneficial photovoltaic properties indicated for this material

    Intervention trial with calcium montmorillonite clay in a south Texas population exposed to aflatoxin

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    South Texas currently has the highest incidence of hepatocellular carcinoma (HCC) in the United States, a disease that disproportionately affects Latino populations in the region. Aflatoxin B(1) (AFB(1)) is a potent liver carcinogen that has been shown to be present in a variety of foods in the U.S., including corn and corn products. Importantly, it is a dietary risk factor contributing to a higher incidence of HCC in populations frequently consuming AFB(1)-contaminated diets. In a randomized double-blind placebo controlled trial, we evaluated the effects of a three-month administration of ACCS100 (refined calcium montmorillonite clay) on serum AFB(1)-lysine adduct level and serum biochemistry in 234 healthy men and women residing in Bexar and Medina Counties, Texas. Participants recruited from 2012–2014 received either a Placebo, 1.5 g, or 3 g ACCS100 each day for three months, and no treatment during the 4(th) month. Adverse event rates were similar across treatment groups and no significant differences were observed for serum biochemistry and hematology parameters. Differences in levels of AFB(1)-lysine adduct at 1, 3, and 4 months were compared between Placebo and active treatment groups. Although serum AFB(1)-lysine adduct levels were decreased by month 3 for both treatment groups, the Low dose was the only treatment that was significant (p=0.0005). In conclusion, the observed effect in the Low dose treatment group suggests that the use of ACCS100 may be a viable strategy to reduce dietary AFB(1) bioavailability during aflatoxin outbreaks and potentially in populations chronically exposed to this carcinogen

    Diagnostico de vértigo periférico para el médico de atención primaria

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    Para los médicos de atención primaria, el paciente con sintomatología compatible con síndromes vestibulares constituye un desafío, debido a su amplia variedad de presentaciones y la dificultad en la diferenciación de las diversas patologías que  ocasionan los síntomas. La necesidad de tener conceptos claros y actualizados sobre los mecanismos patológicos del vértigo surge en el momento de evaluar al paciente, para esto es necesario realizar un adecuado interrogatorio y un examen físico neurotológico completo que permita dilucidar un abordaje diagnóstico certero. El objetivo del presente artículo es presentar una revisión de la literatura actual, de las diferentes etiologías desencadenantes del vértigo periférico y a partir de sus características clínicas desarrollar un algoritmo diagnóstico que permita al profesional médico entender el mecanismo patológico del vértigo y proporcionar el tratamiento adecuado
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