1,321 research outputs found
Hepatosplenomegaly associated with chronic malaria exposure: evidence for a pro-inflammatory mechanism exacerbated by schistosomiasis
In sub-Saharan Africa, chronic hepatosplenomegaly, with palpable firm/hard organ consistency, is common, particularly among school-aged children. This morbidity can be caused by long-term exposure to malaria, or by Schistosoma mansoni, and it is exacerbated when these two occur together. Although immunological mechanisms probably underlie the pathogenic process, these mechanisms have not been identified, nor is it known whether the two parasites augment the same mechanisms or induce unrelated processes that nonetheless have additive or synergistic effects. Kenyan primary schoolchildren, living in a malaria/schistosomiasis co-transmission area, participated in cross-sectional parasitological and clinical studies in which circulating immune modulator levels were also measured. Plasma IL-12p70, sTNF-RII, IL-10 and IL-13 levels correlated with relative exposure to malaria, and with hepatosplenomegaly. Soluble-TNF-RII and IL-10 were higher in children infected withS. mansoniHepatosplenomegaly caused by chronic exposure to malaria was clearly associated with increased circulating levels of pro-inflammatory mediators, with higher levels of regulatory modulators, and with tissue repair cytokines, perhaps being required to control the inflammatory response. The higher levels of regulatory modulators amongstS. mansoniinfected children, compared to those without detectableS. mansoni and malarial infections, but exposed to malaria, suggest thatS. mansoniinfection may augment the underlying inflammatory reaction
ANTAGONISTIC EFFECTS OF BIOCONTROL AGENTS AGAINST Phytophthora infestans AND GROWTH STIMULATION IN TOMATOES
Late blight disease is a major cause of economic losses in tomato (
Lycopersicon esculentum L.) production in eastern Africa. The
objective of this study was to evaluate the efficacy of Trichoderma
species in controlling late blight disease and their role on the growth
of tomato. Trichoderma asperellum and T. harzianum were isolated
from two commercial products containing the antagonistic species.
Culture-based and molecular approaches, genomic DNA isolation and
amplification, using ITS1 and ITS4 universal primers, and sequencing,
were used to characterise the products. Trichoderma antagonistic
effects against Phytophthora infestans (causative of tomato late
blight) experiments were conducted in vitro and in the greenhouse. The
greenhouse experiment had five treatments; namely, a negative control,
Metalaxl-M, T. asperellum, T. harzanium and mixture of the two
biocontrol agents, laid out in a randomised complete block design. The
experiment was carried out for 12 weeks, with 3 weeks measurements
intervals. Morphological and molecular characterisation confirmed the
organism in most of the commercial products as T. harzianum and T.
asperellum. An inhibiting action was observed on the P. Infestans
mycelial growth, by the effect of T. asperellum (30.7%), and T.
harzianum (36.9%).Trichoderma spp. suppressed late blight disease in
the greenhouse experiment. These effects were specific to soil type,
with the higher effectiveness realised in Ferralsols (27% disease
severity) and least in Nitisols (36% disease severity). Trichoderma
harzianum and T. asperellum resulted in higher above ground biomass of
tomato of 31 and 19% increase over the control, respectively. There is
potential of biocontrol agents in reducing P. infestans effects in
tomatoes and in stimulating growth.La maladie du mildiou est une cause majeure de pertes \ue9conomiques
dans la production de tomate ( Lycopersicon esculentum L.) en Afrique
de l\u2019Est. L\u2019objectif de cette \ue9tude \ue9tait
d\u2019\ue9valuer l\u2019efficacit\ue9 des esp\ue8ces de
Trichoderma dans la lutte contre le mildiou et leur r\uf4le sur la
croissance de la tomate. Trichoderma asperellum et T. harzianum ont
\ue9t\ue9 isol\ue9s de deux produits commerciaux contenant les
esp\ue8ces antagonistes. En se basant sur la culture et des approches
mol\ue9culaires, l\u2019isolement de l\u2019ADN g\ue9nomique et
l\u2019amplification, en utilisant des amorces universelles ITS1 et
ITS4, et le s\ue9quen\ue7age ont \ue9t\ue9 utilis\ue9s pour
caract\ue9riser les produits. Des effets antagonistes de Trichoderma
contre Phytophthora infestans (causant le mildiou de la tomate) ont
\ue9t\ue9 men\ue9s in vitro et en serre. L\u2019exp\ue9rience
en serre a eu cinq traitements; \ue0 savoir, un contr\uf4le
n\ue9gatif, Metalaxl-M, T. asperellum, T. harzanium et un
m\ue9lange des deux agents de lutte biologique, dispos\ue9s dans un
mod\ue8le de bloc complet randomis\ue9. L\u2019exp\ue9rience a
dur\ue9 12 semaines, avec des intervalles de mesure de 3 semaines. La
caract\ue9risation morphologique et mol\ue9culaire a confirm\ue9
l\u2019organisme dans la plupart des produits commerciaux comme T.
harzianum et T. asperellum. Une action inhibitrice a \ue9t\ue9
observ\ue9e sur la croissance myc\ue9lienne de P. Infestans, sous
l\u2019effet de T. asperellum (30,7%) et T. harzianum (36,9%).
Trichoderma spp. supprim\ue9 la maladie du mildiou dans
l\u2019exp\ue9rience en serre. Ces effets \ue9taient
sp\ue9cifiques au type de sol, avec une efficacit\ue9 plus
\ue9lev\ue9e r\ue9alis\ue9e dans les Ferralsols (27% de
gravit\ue9 de la maladie) et moins dans les Nitisols (36% de
gravit\ue9 de la maladie). Trichoderma harzianum et T. asperellum ont
entra\ueen\ue9 une augmentation de la biomasse a\ue9rienne de la
tomate de 31 et 19% par rapport au t\ue9moin, respectivement. Les
agents de lutte biologique peuvent r\ue9duire les effets de P.
infestans sur les tomates et stimuler la croissance
Magnitude and factors associated with nonadherence to antiepileptic drug treatment in Africa: A cross-sectional multisite study
Objectives: The epilepsy treatment gap is large in low- and middle-income countries, but the reasons behind nonadherence to treatment with antiepileptic drugs (AEDs) across African countries remain unclear. We investigated the extent to which AEDs are not taken and associated factors in people with active convulsive epilepsy (ACE) identified in cross-sectional studies conducted in five African countries. Methods: We approached 2,192 people with a confirmed diagnosis of ACE for consent to give blood voluntarily. Participants were asked if they were taking AEDs, and plasma drug concentrations were measured using a fluorescence polarization immunoassay analyzer. Information about possible risk factors was collected using questionnaire-based clinical interviews. We determined factors associated with nonadherence to AED treatment in children and adults, as measured by detectable and optimal levels, using multilevel logistic regression. Results: In 1,303 samples assayed (43.7% were children), AEDs were detected in 482, but only 287 had optimal levels. Of the 1,303 samples, 532 (40.8%) were from people who had reported they were on AEDs. The overall prevalence of nonadherence to treatment was 63.1% (95% confidence interval [CI] 60.5â65.6%) as measured by detectable AED levels and 79.1% (95% CI 73.3â84.3%) as measured by optimal AED levels; self-reported nonadherence was 65.1% (95% CI 45.0â79.5%). Nonadherence was significantly (p < 0.001) more common among the children than among adults for optimal and detectable levels of AEDs, as was the self-reported nonadherence. In children, lack of previous hospitalization and learning difficulties were independently associated with nonadherence to treatment. In adults, history of delivery at home, absence of burn marks, and not seeking traditional medicine were independently associated with the nonadherence to AED treatment. Significance: Only about 20% of people with epilepsy benefit fully from antiepileptic drugs in sub-Saharan Africa, according to optimum AEDs levels. Children taking AEDs should be supervised to promote compliance
Epidemiology of Coxiella burnetii infection in Africa: a OneHealth systematic review
Background:
Q fever is a common cause of febrile illness and community-acquired pneumonia in resource-limited settings. Coxiella burnetii, the causative pathogen, is transmitted among varied host species, but the epidemiology of the organism in Africa is poorly understood. We conducted a systematic review of C. burnetii epidemiology in Africa from a âOne Healthâ perspective to synthesize the published data and identify knowledge gaps.<p></p>
Methods/Principal Findings:
We searched nine databases to identify articles relevant to four key aspects of C. burnetii epidemiology in human and animal populations in Africa: infection prevalence; disease incidence; transmission risk factors; and infection control efforts. We identified 929 unique articles, 100 of which remained after full-text review. Of these, 41 articles describing 51 studies qualified for data extraction. Animal seroprevalence studies revealed infection by C. burnetii (≤13%) among cattle except for studies in Western and Middle Africa (18â55%). Small ruminant seroprevalence ranged from 11â33%. Human seroprevalence was <8% with the exception of studies among children and in Egypt (10â32%). Close contact with camels and rural residence were associated with increased seropositivity among humans. C. burnetii infection has been associated with livestock abortion. In human cohort studies, Q fever accounted for 2â9% of febrile illness hospitalizations and 1â3% of infective endocarditis cases. We found no studies of disease incidence estimates or disease control efforts.<p></p>
Conclusions/Significance:
C. burnetii infection is detected in humans and in a wide range of animal species across Africa, but seroprevalence varies widely by species and location. Risk factors underlying this variability are poorly understood as is the role of C. burnetii in livestock abortion. Q fever consistently accounts for a notable proportion of undifferentiated human febrile illness and infective endocarditis in cohort studies, but incidence estimates are lacking. C. burnetii presents a real yet underappreciated threat to human and animal health throughout Africa.<p></p>
Linkage of Type I Interferon Activity and TNF-Alpha Levels in Serum with Sarcoidosis Manifestations and Ancestry
BACKGROUND: Both type I interferon (IFN), also known as IFN-α and tumor necrosis factor alpha (TNF-α) have been implicated in the pathogenesis of sarcoidosis. We investigated serum levels of these cytokines in a large multi-ancestral sarcoidosis population to determine correlations between cytokine levels and disease phenotypes. METHODS: We studied serum samples from 98 patients with sarcoidosis, including 71 patients of African-American ancestry and 27 patients of European-American ancestry. Serum type I IFN was measured using a sensitive reporter cell assay and serum TNF-α was measured using a commercial ELISA kit. Clinical data including presence or absence of neurologic, cardiac, and severe pulmonary manifestations of sarcoidosis were abstracted from medical records. Twenty age-matched non-autoimmune controls were also studied from each ancestral background. Differences in cytokine levels between groups were analyzed with Mann-Whitney U test, and correlations were assessed using Spearman's rho. Multivariate logistic regression models were used to detect associations between cytokines and clinical manifestations. RESULTS: Significant differences in cytokine levels were observed between African- and European-American patients with sarcoidosis. In African-Americans, serum TNF-α levels were significantly higher relative to matched controls (Pâ=â0.039), and patients with neurologic disease had significantly higher TNF-α than patients lacking this manifestation (Pâ=â0.022). In European-Americans, serum type I IFN activity was higher in sarcoidosis cases as compared to matched controls, and patients with extra-pulmonary disease represented a high serum IFN subgroup (Pâ=â0.0032). None of the associations observed were shared between the two ancestral groups. CONCLUSIONS: Our data indicate that significant associations between serum levels of TNF-α and type I IFN and clinical manifestations exist in a sarcoidosis cohort that differ significantly by self-reported ancestry. In each ancestral background, the cytokine elevated in patients with sarcoidosis was also associated with a particular disease phenotype. These findings may relate to ancestral differences in the molecular pathogenesis of this heterogeneous disease
Observation of an Excited Bc+ State
Using pp collision data corresponding to an integrated luminosity of 8.5 fb-1 recorded by the LHCb experiment at center-of-mass energies of s=7, 8, and 13 TeV, the observation of an excited Bc+ state in the Bc+Ï+Ï- invariant-mass spectrum is reported. The observed peak has a mass of 6841.2±0.6(stat)±0.1(syst)±0.8(Bc+) MeV/c2, where the last uncertainty is due to the limited knowledge of the Bc+ mass. It is consistent with expectations of the Bcâ(2S31)+ state reconstructed without the low-energy photon from the Bcâ(1S31)+âBc+Îł decay following Bcâ(2S31)+âBcâ(1S31)+Ï+Ï-. A second state is seen with a global (local) statistical significance of 2.2Ï (3.2Ï) and a mass of 6872.1±1.3(stat)±0.1(syst)±0.8(Bc+) MeV/c2, and is consistent with the Bc(2S10)+ state. These mass measurements are the most precise to date
Bose-Einstein correlations of same-sign charged pions in the forward region in pp collisions at âs=7 TeV
Bose-Einstein correlations of same-sign charged pions, produced in protonproton collisions at a 7 TeV centre-of-mass energy, are studied using a data sample collected
by the LHCb experiment. The signature for Bose-Einstein correlations is observed in the
form of an enhancement of pairs of like-sign charged pions with small four-momentum
difference squared. The charged-particle multiplicity dependence of the Bose-Einstein correlation parameters describing the correlation strength and the size of the emitting source
is investigated, determining both the correlation radius and the chaoticity parameter. The
measured correlation radius is found to increase as a function of increasing charged-particle
multiplicity, while the chaoticity parameter is seen to decreas
Study of charmonium production in b -hadron decays and first evidence for the decay Bs0
Using decays to Ï-meson pairs, the inclusive production of charmonium states in b-hadron decays is studied with pp collision data corresponding to an integrated luminosity of 3.0 fbâ1, collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. Denoting byBC ⥠B(b â C X) Ă B(C â ÏÏ) the inclusive branching fraction of a b hadron to a charmonium state C that decays into a pair of Ï mesons, ratios RC1C2 ⥠BC1 /BC2 are determined as RÏc0ηc(1S) = 0.147 ± 0.023 ± 0.011, RÏc1ηc(1S) =0.073 ± 0.016 ± 0.006, RÏc2ηc(1S) = 0.081 ± 0.013 ± 0.005,RÏc1 Ïc0 = 0.50 ± 0.11 ± 0.01, RÏc2 Ïc0 = 0.56 ± 0.10 ± 0.01and Rηc(2S)ηc(1S) = 0.040 ± 0.011 ± 0.004. Here and below the first uncertainties are statistical and the second systematic.Upper limits at 90% confidence level for the inclusive production of X(3872), X(3915) and Ïc2(2P) states are obtained as RX(3872)Ïc1 < 0.34, RX(3915)Ïc0 < 0.12 andRÏc2(2P)Ïc2 < 0.16. Differential cross-sections as a function of transverse momentum are measured for the ηc(1S) andÏc states. The branching fraction of the decay B0s â ÏÏÏ is measured for the first time, B(B0s â ÏÏÏ) = (2.15±0.54±0.28±0.21B)Ă10â6. Here the third uncertainty is due to the branching fraction of the decay B0s â ÏÏ, which is used for normalization. No evidence for intermediate resonances is seen. A preferentially transverse Ï polarization is observed.The measurements allow the determination of the ratio of the branching fractions for the ηc(1S) decays to ÏÏ and p p asB(ηc(1S)â ÏÏ)/B(ηc(1S)â p p) = 1.79 ± 0.14 ± 0.32
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