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1.
Malar J ; 22(1): 315, 2023 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-37853408

RESUMO

BACKGROUND: In rural African settings, most of the children under the coverage of Seasonal Malaria Chemoprevention (SMC) are also undernourished at the time of SMC delivery, justifying the need for packaging malarial and nutritional interventions. This study aimed at assessing the impact of SMC by coupling the intervention with nutrients supplementation for preventing malaria in children less than 5 years old in Burkina Faso. METHODS: A randomized trial was carried out between July 2020 and June 2021 in the health district of Nanoro, Burkina Faso. Children (n = 1059) under SMC coverage were randomly assigned to one of the three study arms SMC + Vitamin A (SMC-A, n = 353) or SMC + Vitamin A + Zinc (SMC-AZc, n = 353) or SMC + Vitamin A + PlumpyDoz(tm) (SMC-APd, n = 353)-a medium quantity-lipid-based nutrient supplement (MQ-LNS). Children were followed up for one year that included an active follow-up period of 6 months with scheduled monthly home visits followed by 6 months passive follow-up. At each visit, capillary blood sample was collected for malaria diagnosis by rapid diagnosis test (RDT). RESULTS: Adding nutritional supplements to SMC had an effect on the incidence of malaria. A reduction of 23% (adjusted IRR = 0.77 (95%CI 0.61-0.97) in the odds of having uncomplicated malaria in SMC-APd arm but not with SMC-AZc arm adjusted IRR = 0.82 (95%CI 0.65-1.04) compare to control arm was observed. A reduction of 52%, adjusted IRR = 0.48 (95%CI 0.23-0.98) in the odds of having severe malaria was observed in SMC-APd arm compared to control arm. Besides the effect on malaria, this combined strategy had an effect on all-cause morbidity. More specifically, a reduction of morbidity odds of 24%, adjusted IRR = 0.76 (95%CI 0.60-0.94) in SMC-APd arm compared to control arm was observed. Unlike clinical episodes, no effect of nutrient supplementation on cross sectional asymptomatic infections was observed. CONCLUSION: Adding nutritional supplements to SMC significantly increases the impact of this intervention for preventing children from malaria and other childhood infections. TRIAL REGISTRATION: NCT04238845.


Assuntos
Antimaláricos , Malária , Pré-Escolar , Humanos , Lactente , Antimaláricos/uso terapêutico , Burkina Faso/epidemiologia , Quimioprevenção , Estudos Transversais , Suplementos Nutricionais , Malária/epidemiologia , Nutrientes , Estações do Ano , Vitamina A/uso terapêutico
2.
Respir Med ; 217: 107309, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37394196

RESUMO

BACKGROUND AND AIM: Few questionnaires are available for routine assessment of dyspnea. The study aimed to design a self-administered questionnaire assessing the impact of chronic dyspnea on daily activities, named DYSLIM (Dyspnea-induced Limitation). METHODS: The development followed 4 steps: 1: selection of relevant activities and related questions (focus groups); 2: clinical study: internal and concurrent validity vs. modified Medical Research Council (mMRC), Baseline Dyspnea Index (BDI) and Saint George Respiratory Questionnaire (SGRQ); 3: item reduction; 4: responsiveness. Eighteen activities (from eating to climbing stairs) were considered with 5 modalities for each: doing the task slowly, taking breaks, seeking assistance, changing habits, and activity avoidance. Each modality was graded from 5 (never) to 1 (very often). Validation study included 194 patients: COPD (FEV1 ≥ 50% pred: n = 40; FEV1 < 50% pred: n = 65); cystic fibrosis (n = 30), interstitial lung disease (n = 30), pulmonary hypertension (n = 29). Responsiveness was evaluated by post-pulmonary rehabilitation data in 52 COPD patients. RESULTS: Acceptability was high and short term (7 days) reproducibility was satisfactory (Kappa mostly above 0.7). Concurrent validity was high vs. mMRC (Spearman correlation coefficient, r = 0.71), BDI (r = - 0.75) and SGRQ (r = - 0.79). The reduced questionnaire with 8 activities (from cleaning to climbing stairs) and 3 modalities (slowly, seeking help, changing habits) showed a comparable validity and was chosen as the final short version. Effect size of rehabilitation was good for both the full (0.57) and short (0.51) versions. A significant correlation was also found between changes of SGRQ and DYSLIM post rehabilitation: r = - 0.68 and r = - 0.60 for full and reduced questionnaires, respectively. CONCLUSION: The DYSLIM questionnaire appears promising for the evaluation of dyspnea-induced limitations in chronic respiratory diseases and seems suitable for use in various contexts.


Assuntos
Doença Pulmonar Obstrutiva Crônica , Humanos , Doença Pulmonar Obstrutiva Crônica/complicações , Reprodutibilidade dos Testes , Dispneia/diagnóstico , Dispneia/etiologia , Inquéritos e Questionários , Atividades Cotidianas , Qualidade de Vida
3.
PLoS Comput Biol ; 18(8): e1010317, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35951528

RESUMO

BACKGROUND: Sulfadoxine-pyrimethamine (SP) is recommended in Africa in several antimalarial preventive regimens including Intermittent Preventive Treatment in pregnant women (IPTp), Intermittent Preventive Treatment in infants (IPTi) and Seasonal Malaria Chemoprevention (SMC). The effectiveness of SP-based preventive treatments are threatened in areas where Plasmodium falciparum resistance to SP is high. The prevalence of mutations in the dihydropteroate synthase gene (pfdhps) can be used to monitor SP effectiveness. IPTi-SP is recommended only in areas where the prevalence of the pfdhps540E mutation is below 50%. It has also been suggested that IPTp-SP does not have a protective effect in areas where the pfdhps581G mutation, exceeds 10%. However, pfdhps mutation prevalence data in Africa are extremely heterogenous and scattered, with data completely missing from many areas. METHODS AND FINDINGS: The WWARN SP Molecular Surveyor database was designed to summarize dihydrofolate reductase (pfdhfr) and pfdhps gene mutation prevalence data. In this paper, pfdhps mutation prevalence data was used to generate continuous spatiotemporal surface maps of the estimated prevalence of the SP resistance markers pfdhps437G, pfdhps540E, and pfdhps581G in Africa from 1990 to 2020 using a geostatistical model, with a Bayesian inference framework to estimate uncertainty. The maps of estimated prevalence show an expansion of the pfdhps437G mutations across the entire continent over the last three decades. The pfdhps540E mutation emerged from limited foci in East Africa to currently exceeding 50% estimated prevalence in most of East and South East Africa. pfdhps540E distribution is expanding at low or moderate prevalence in central Africa and a predicted focus in West Africa. Although the pfdhps581G mutation spread from one focus in East Africa in 2000, to exceeding 10% estimated prevalence in several foci in 2010, the predicted distribution of the marker did not expand in 2020, however our analysis indicated high uncertainty in areas where pfdhps581G is present. Uncertainty was higher in spatial regions where the prevalence of a marker is intermediate or where prevalence is changing over time. CONCLUSIONS: The WWARN SP Molecular Surveyor database and a set of continuous spatiotemporal surface maps were built to provide users with standardized, current information on resistance marker distribution and prevalence estimates. According to the maps, the high prevalence of pfdhps540E mutation was to date restricted to East and South East Africa, which is reassuring for continued use of IPTi and SMC in West Africa, but continuous monitoring is needed as the pfdhps540E distribution is expanding. Several foci where pfdhps581G prevalence exceeded 10% were identified. More data on the pfdhps581G distribution in these areas needs to be collected to guide IPTp-SP recommendations. Prevalence and uncertainty maps can be utilized together to strategically identify sites where increased surveillance can be most informative. This study combines a molecular marker database and predictive modelling to highlight areas of concern, which can be used to support decisions in public health, highlight knowledge gaps in certain regions, and guide future research.


Assuntos
Antimaláricos , Malária Falciparum , Malária , Antimaláricos/farmacologia , Antimaláricos/uso terapêutico , Teorema de Bayes , Combinação de Medicamentos , Resistência a Medicamentos/genética , Feminino , Humanos , Malária/tratamento farmacológico , Malária Falciparum/tratamento farmacológico , Malária Falciparum/epidemiologia , Malária Falciparum/prevenção & controle , Mutação , Plasmodium falciparum/genética , Gravidez , Pirimetamina/farmacologia , Pirimetamina/uso terapêutico , África do Sul , Sulfadoxina , Tetra-Hidrofolato Desidrogenase/genética
4.
Malar J ; 21(1): 83, 2022 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-35279140

RESUMO

BACKGROUND: Resistance to anti-malarials is a serious threat to the efforts to control and eliminate malaria. Surveillance based on simple field protocols with centralized testing to detect molecular markers associated with anti-malarial drug resistance can be used to identify locations where further investigations are needed. METHODS: Dried blood spots were collected from 398 patients (age range 5-59 years, 99% male) with Plasmodium falciparum infections detected using rapid diagnostic tests over two rounds of sample collection conducted in 2016 and 2017 in Komé, South-West Chad. Specimens were genotyped using amplicon sequencing or qPCR for validated markers of anti-malarial resistance including partner drugs used in artemisinin-based combination therapy (ACT). RESULTS: No mutations in the pfk13 gene known to be associated with artemisinin resistance were found but a high proportion of parasites carried other mutations, specifically K189T (190/349, 54.4%, 95%CI 49.0-59.8%). Of 331 specimens successfully genotyped for pfmdr1 and pfcrt, 52% (95%CI 46.4-57.5%) carried the NFD-K haplotype, known to be associated with reduced susceptibility to lumefantrine. Only 20 of 336 (6.0%, 95%CI 3.7-9.0%) had parasites with the pfmdr1-N86Y polymorphism associated with increased treatment failures with amodiaquine. Nearly all parasites carried at least one mutation in pfdhfr and/or pfdhps genes but 'sextuple' mutations in pfdhfr-pfdhps including pfdhps -A581G were rare (8/336 overall, 2.4%, 95%CI 1.2-4.6%). Only one specimen containing parasites with pfmdr1 gene amplification was detected. CONCLUSIONS: These results provide information on the likely high efficacy of artemisinin-based combinations commonly used in Chad, but suggest decreasing levels of sensitivity to lumefantrine and high levels of resistance to sulfadoxine-pyrimethamine used for seasonal malaria chemoprevention and intermittent preventive therapy in pregnancy. A majority of parasites had mutations in the pfk13 gene, none of which are known to be associated with artemisinin resistance. A therapeutic efficacy study needs to be conducted to confirm the efficacy of artemether-lumefantrine.


Assuntos
Antimaláricos , Plasmodium falciparum , Adolescente , Adulto , Antimaláricos/farmacologia , Antimaláricos/uso terapêutico , Artemeter , Combinação Arteméter e Lumefantrina , Chade , Criança , Pré-Escolar , Resistência a Medicamentos/genética , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Plasmodium falciparum/genética , Polimorfismo Genético , Proteínas de Protozoários/genética , Adulto Jovem
5.
Arch Public Health ; 80(1): 41, 2022 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-35081964

RESUMO

BACKGROUND: Plasmodium falciparum malaria remains a major public health concern in sub-Sahara Africa. Seasonal malaria chemoprevention (SMC) with amodiaquine + sulfadoxine-pyrimethamine is one of the most important preventive interventions. Despite its implementation, the burden of malaria is still very high in children under five years old in Burkina Faso, suggesting that the expected impact of this promising strategy might not be attained. Development of innovative strategies to improve the efficacy of these existing malaria control measures is essential. In such context, we postulate that screening and treatment of malaria in household members of children receiving SMC could greatly improve the impact of SMC intervention and reduce malaria transmission in endemic settings. METHODS: This randomized superiority trial will be carried out in the Nanoro health district, Burkina Faso. The unit of randomisation will be the household and all eligible children from a household will be allocated to the same study group. Households with 3-59 months old children will be assigned to either (i) control group (SMC alone) or (ii) intervention (SMC+ screening of household members with standard Histidin Rich Protein Rapid Diagnostic Test (HRP2-RDT) and treatment if positive). The sample size will be 526 isolated households per arm, i.e., around 1052 children under SMC coverage and an expected 1315 household members. Included children will be followed-up for 24 months to fully cover two consecutive malaria transmission seasons and two SMC cycles. Children will be actively followed-up during the malaria transmission seasons while in the dry seasons the follow-up will be passive. CONCLUSION: The study will respond to a major public health concern by providing evidence of the efficacy of an innovative strategy to boost the impact of SMC intervention.

6.
BMC Med ; 18(1): 47, 2020 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-32098634

RESUMO

BACKGROUND: The majority of Plasmodium falciparum malaria cases in Africa are treated with the artemisinin combination therapies artemether-lumefantrine (AL) and artesunate-amodiaquine (AS-AQ), with amodiaquine being also widely used as part of seasonal malaria chemoprevention programs combined with sulfadoxine-pyrimethamine. While artemisinin derivatives have a short half-life, lumefantrine and amodiaquine may give rise to differing durations of post-treatment prophylaxis, an important additional benefit to patients in higher transmission areas. METHODS: We analyzed individual patient data from 8 clinical trials of AL versus AS-AQ in 12 sites in Africa (n = 4214 individuals). The time to PCR-confirmed reinfection after treatment was used to estimate the duration of post-treatment protection, accounting for variation in transmission intensity between settings using hidden semi-Markov models. Accelerated failure-time models were used to identify potential effects of covariates on the time to reinfection. The estimated duration of chemoprophylaxis was then used in a mathematical model of malaria transmission to determine the potential public health impact of each drug when used for first-line treatment. RESULTS: We estimated a mean duration of post-treatment protection of 13.0 days (95% CI 10.7-15.7) for AL and 15.2 days (95% CI 12.8-18.4) for AS-AQ overall. However, the duration varied significantly between trial sites, from 8.7-18.6 days for AL and 10.2-18.7 days for AS-AQ. Significant predictors of time to reinfection in multivariable models were transmission intensity, age, drug, and parasite genotype. Where wild type pfmdr1 and pfcrt parasite genotypes predominated (<=20% 86Y and 76T mutants, respectively), AS-AQ provided ~ 2-fold longer protection than AL. Conversely, at a higher prevalence of 86Y and 76T mutant parasites (> 80%), AL provided up to 1.5-fold longer protection than AS-AQ. Our simulations found that these differences in the duration of protection could alter population-level clinical incidence of malaria by up to 14% in under-5-year-old children when the drugs were used as first-line treatments in areas with high, seasonal transmission. CONCLUSION: Choosing a first-line treatment which provides optimal post-treatment prophylaxis given the local prevalence of resistance-associated markers could make a significant contribution to reducing malaria morbidity.


Assuntos
Amodiaquina/uso terapêutico , Antimaláricos/uso terapêutico , Combinação Arteméter e Lumefantrina/uso terapêutico , Artemisininas/uso terapêutico , Malária Falciparum/tratamento farmacológico , Plasmodium falciparum/patogenicidade , Amodiaquina/farmacologia , Antimaláricos/farmacologia , Combinação Arteméter e Lumefantrina/farmacologia , Artemisininas/farmacologia , Pré-Escolar , Combinação de Medicamentos , Feminino , Humanos , Lactente , Masculino
7.
Malar J ; 17(1): 98, 2018 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-29486766

RESUMO

BACKGROUND: In Niger, malaria transmission is markedly seasonal with most of the disease burden occurring in children during the rainy season. Seasonal malaria chemoprevention (SMC) with amodiaquine plus sulfadoxine-pyrimethamine (AQ + SP) is recommended in the country to be administered monthly just before and during the rainy season. Moreover, clinical decisions on use of SP for intermittent preventive treatment in pregnancy (IPTp) now depend upon the validated molecular markers for SP resistance in Plasmodium falciparum observed in the local parasite population. However, little is known about molecular markers of resistance for either SP or AQ in the south of Niger. To address this question, clinical samples which met clinical and biological criteria, were collected in Gabi, Madarounfa district, Maradi region, Niger in 2011-2012 (before SMC implementation). Molecular markers of resistance to pyrimethamine (pfdhfr), sulfadoxine (pfdhps) and amodiaquine (pfmdr1) were assessed by DNA sequencing. RESULTS: Prior to SMC implementation, the samples showed a high proportion of clinical samples that carried the pfdhfr 51I/59R/108N haplotype associated with resistance to pyrimethamine and pfdhps 436A/F/H and 437G mutations associated with reduced susceptibility to sulfadoxine. In contrast mutations in codons 581G, and 613S in the pfdhps gene, and in pfmdr1, 86Y, 184Y, 1042D and 1246Y associated with resistance to amodiaquine, were less frequently observed. Importantly, pfdhfr I164L and pfdhps K540E mutations shown to be the most clinically relevant markers for high level clinical resistance to SP were not detected in Gabi. CONCLUSIONS: Although parasites with genotypes associated with the highest levels of resistance to AQ + SP are not yet common in this setting, their importance for deployment of SMC and IPTp dictates that monitoring of these markers of resistance should accompany these interventions. This study also highlights the parasite heterogeneity within a small spatial area and the need to use caution when extrapolating results from surveys of molecular markers of resistance in a single site to inform regional policy decisions.


Assuntos
Amodiaquina/farmacologia , Antimaláricos/farmacologia , Di-Hidropteroato Sintase/genética , Resistência a Medicamentos , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Plasmodium falciparum/efeitos dos fármacos , Proteínas de Protozoários/genética , Pirimetamina/farmacologia , Sulfadoxina/farmacologia , Tetra-Hidrofolato Desidrogenase/genética , Amodiaquina/uso terapêutico , Antimaláricos/uso terapêutico , Quimioprevenção/métodos , Pré-Escolar , Combinação de Medicamentos , Feminino , Genótipo , Humanos , Lactente , Malária Falciparum/parasitologia , Malária Falciparum/prevenção & controle , Masculino , Administração Massiva de Medicamentos , Proteínas Mutantes/genética , Níger , Plasmodium falciparum/genética , Plasmodium falciparum/isolamento & purificação , Pirimetamina/uso terapêutico , Estações do Ano , Análise de Sequência de DNA , Sulfadoxina/uso terapêutico
8.
Microbiologyopen ; 6(4)2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28397370

RESUMO

The extreme radiation resistance of Deinococcus bacteria requires the radiation-stimulated cleavage of protein DdrO by a specific metalloprotease called IrrE. DdrO is the repressor of a predicted radiation/desiccation response (RDR) regulon, composed of radiation-induced genes having a conserved DNA motif (RDRM) in their promoter regions. Here, we showed that addition of zinc ions to purified apo-IrrE, and short exposure of Deinococcus cells to zinc ions, resulted in cleavage of DdrO in vitro and in vivo, respectively. Binding of IrrE to RDRM-containing DNA or interaction of IrrE with DNA-bound DdrO was not observed. The data are in line with IrrE being a zinc peptidase, and indicate that increased zinc availability, caused by oxidative stress, triggers the in vivo cleavage of DdrO unbound to DNA. Transcriptomics and proteomics of Deinococcus deserti confirmed the IrrE-dependent regulation of predicted RDR regulon genes and also revealed additional members of this regulon. Comparative analysis showed that the RDR regulon is largely well conserved in Deinococcus species, but also showed diversity in the regulon composition. Notably, several RDR genes with an important role in radiation resistance in Deinococcus radiodurans, for example pprA, are not conserved in some other radiation-resistant Deinococcus species.


Assuntos
Proteínas de Bactérias/metabolismo , Deinococcus/genética , Deinococcus/efeitos da radiação , Variação Genética , Estresse Fisiológico , Proteínas de Bactérias/genética , Deinococcus/classificação , Deinococcus/metabolismo , Regulação Bacteriana da Expressão Gênica , Metaloproteases/genética , Metaloproteases/metabolismo , Regulon , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo
9.
Sci Rep ; 6: 24508, 2016 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-27072056

RESUMO

Placental malaria caused by Plasmodium falciparum contributes to ~200,000 child deaths annually, mainly due to low birth weight (LBW). Parasitized erythrocyte sequestration and consequent inflammation in the placenta are common attributes of placental malaria. The precise molecular details of placental changes leading to LBW are still poorly understood. We hypothesized that placental malaria may disturb maternofetal exchange of vitamins, lipids, and hormones mediated by the multi-ligand (n ~ 50) scavenging/signaling receptor megalin, which is abundantly expressed in placenta but was not previously analyzed in pregnancy outcomes. We studied abundance of megalin and its intracellular adaptor protein Dab2 by immunofluorescence microscopy in placental biopsies from Ugandan women with (n = 8) and without (n = 20) active placental malaria. We found that: (a) abundances of both megalin (p = 0.01) and Dab2 (p = 0.006) were significantly reduced in brush border of syncytiotrophoblast of infected placentas; (b) amounts of megalin and Dab2 were strongly correlated (Spearman's r = 0.53, p = 0.003); (c) abundances of megalin and Dab2 (p = 0.046) were reduced in infected placentas from women with LBW deliveries. This study provides first evidence that placental malaria infection is associated with reduced abundance of megalin transport/signaling system and indicate that these changes may contribute to the pathology of LBW.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Recém-Nascido de Baixo Peso , Proteína-2 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Malária Falciparum/metabolismo , Doenças Placentárias/metabolismo , Trofoblastos/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Proteínas Reguladoras de Apoptose , Feminino , Humanos , Malária Falciparum/patologia , Gravidez , Resultado da Gravidez
10.
BMC Med ; 13: 305, 2015 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-26695060

RESUMO

BACKGROUND: The declining efficacy of dihydroartemisinin-piperaquine against Plasmodium falciparum in Cambodia, along with increasing numbers of recrudescent cases, suggests resistance to both artemisinin and piperaquine. Available in vitro piperaquine susceptibility assays do not correlate with treatment outcome. A novel assay using a pharmacologically relevant piperaquine dose/time exposure was designed and its relevance explored in retrospective and prospective studies. METHODS: The piperaquine survival assay (PSA) exposed parasites to 200 nM piperaquine for 48 hours and monitored survival 24 hours later. The retrospective study tested 32 culture-adapted, C580Y-K13 mutant parasites collected at enrolment from patients treated with a 3-day course of dihydroartemisinin-piperaquine and having presented or not with a recrudescence at day 42 (registered ACTRN12615000793516). The prospective study assessed ex vivo PSA survival rate alongside K13 polymorphism of isolates collected from patients enrolled in an open-label study with dihydroartemisinin-piperaquine for uncomplicated P. falciparum malaria in Cambodia (registered ACTRN12615000696594). RESULTS: All parasites from recrudescent cases had in vitro or ex vivo PSA survival rates ≥10%, a relevant cut-off value for piperaquine-resistance. Ex vivo PSA survival rates were higher for recrudescent than non-recrudescent cases (39.2% vs. 0.17%, P <1 × 10(-7)). Artemisinin-resistant K13 mutants with ex vivo PSA survival rates ≥10% were associated with 32-fold higher risk of recrudescence (95% CI, 4.5-224; P = 0.0005). CONCLUSION: PSA adequately captures the piperaquine resistance/recrudescence phenotype, a mainstay to identify molecular marker(s) and evaluate efficacy of alternative drugs. Combined ex vivo PSA and K13 genotyping provides a convenient monitor for both artemisinin and piperaquine resistance where dihydroartemisinin-piperaquine is used.


Assuntos
Artemisininas/farmacologia , Plasmodium falciparum/genética , Quinolinas/farmacologia , Adolescente , Adulto , Animais , Antimaláricos/uso terapêutico , Camboja , Feminino , Humanos , Malária Falciparum/tratamento farmacológico , Malária Falciparum/mortalidade , Masculino , Parasitos , Estudos Prospectivos , Estudos Retrospectivos , Taxa de Sobrevida , Falha de Tratamento , Resultado do Tratamento , Adulto Jovem
11.
Mol Cell Proteomics ; 9(2): 415-26, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19875382

RESUMO

Deinococcaceae are a family of extremely radiation-tolerant bacteria that are currently subjected to numerous studies aimed at understanding the molecular mechanisms for such radiotolerance. To achieve a comprehensive and accurate annotation of the Deinococcus deserti genome, we performed an N terminus-oriented characterization of its proteome. For this, we used a labeling reagent, N-tris(2,4,6-trimethoxyphenyl)phosphonium acetyl succinimide, to selectively derivatize protein N termini. The large scale identification of N-tris(2,4,6-trimethoxyphenyl)phosphonium acetyl succinimide-modified N-terminal-most peptides by shotgun liquid chromatography-tandem mass spectrometry analysis led to the validation of 278 and the correction of 73 translation initiation codons in the D. deserti genome. In addition, four new genes were detected, three located on the main chromosome and one on plasmid P3. We also analyzed signal peptide cleavages on a genome-wide scale. Based on comparative proteogenomics analysis, we propose a set of 137 corrections to improve Deinococcus radiodurans and Deinococcus geothermalis gene annotations. Some of these corrections affect important genes involved in DNA repair mechanisms such as polA, ligA, and ddrB. Surprisingly, experimental evidences were obtained indicating that DnaA (the protein involved in the DNA replication initiation process) and RpsL (the S12 ribosomal conserved protein) translation is initiated in Deinococcaceae from non-canonical codons (ATC and CTG, respectively). Such use may be the basis of specific regulation mechanisms affecting replication and translation. We also report the use of non-conventional translation initiation codons for two other genes: Deide_03051 and infC. Whether such use of non-canonical translation initiation codons is much more frequent than for other previously reported bacterial phyla or restricted to Deinococcaceae remains to be investigated. Our results demonstrate that predicting translation initiation codons is still difficult for some bacteria and that proteomics-based refinement of genome annotations may be helpful in such cases.


Assuntos
Códon de Iniciação/genética , Deinococcus/genética , Genoma Bacteriano/genética , Biossíntese de Proteínas/genética , Proteômica/métodos , Sequência de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sequência de Bases , Bases de Dados de Proteínas , Genes Bacterianos , Dados de Sequência Molecular , Compostos Organofosforados/química , Compostos Organofosforados/metabolismo , Peptídeos/química , Peptídeos/metabolismo , Sinais Direcionadores de Proteínas , Homologia de Sequência de Aminoácidos , Coloração e Rotulagem
12.
PLoS Negl Trop Dis ; 2(12): e342, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-19048025

RESUMO

BACKGROUND: Neisseria meningitidis serogroup A is the main causative pathogen of meningitis epidemics in sub-Saharan Africa. In recent years, serogroup W135 has also been the cause of epidemics. Mass vaccination campaigns with polysaccharide vaccines are key elements in controlling these epidemics. Facing global vaccine shortage, we explored the use of fractional doses of a licensed A/C/Y/W135 polysaccharide meningococcal vaccine. METHODS AND FINDINGS: We conducted a randomized, non-inferiority trial in 750 healthy volunteers 2-19 years old in Mbarara, Uganda, to compare the immune response of the full dose of the vaccine versus fractional doses (1/5 or 1/10). Safety and tolerability data were collected for all subjects during the 4 weeks following the injection. Pre- and post-vaccination sera were analyzed by measuring serum bactericidal activity (SBA) with baby rabbit complement. A responder was defined as a subject with a > or =4-fold increase in SBA against a target strain from each serogroup and SBA titer > or =128. For serogroup W135, 94% and 97% of the vaccinees in the 1/5- and 1/10-dose arms, respectively, were responders, versus 94% in the full-dose arm; for serogroup A, 92% and 88% were responders, respectively, versus 95%. Non-inferiority was demonstrated between the full dose and both fractional doses in SBA seroresponse against serogroups W135 and Y, in total population analysis. Non-inferiority was shown between the full and 1/5 doses for serogroup A in the population non-immune prior to vaccination. Non-inferiority was not shown for any of the fractionate doses for serogroup C. Safety and tolerability data were favourable, as observed in other studies. CONCLUSIONS: While the advent of conjugate A vaccine is anticipated to largely contribute to control serogroup A outbreaks in Africa, the scale-up of its production will not cover the entire "Meningitis Belt" target population for at least the next 3 to 5 years. In view of the current shortage of meningococcal vaccines for Africa, the use of 1/5 fractional doses should be considered as an alternative in mass vaccination campaigns. TRIAL REGISTRATION: ClinicalTrials.gov NCT00271479.


Assuntos
Vacinas Bacterianas/uso terapêutico , Meningite Meningocócica/imunologia , Neisseria meningitidis/imunologia , Polissacarídeos Bacterianos/uso terapêutico , Adolescente , África Subsaariana/epidemiologia , Animais , Criança , Pré-Escolar , Proteínas do Sistema Complemento/imunologia , Fracionamento da Dose de Radiação , Relação Dose-Resposta a Droga , Humanos , Meningite Meningocócica/epidemiologia , Polissacarídeos Bacterianos/imunologia , Coelhos , Segurança , Método Simples-Cego , Uganda/epidemiologia , Adulto Jovem
13.
J Acquir Immune Defic Syndr ; 45(5): 555-9, 2007 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-17577124

RESUMO

OBJECTIVES: To determine the prevalence, determinants ofpositivity, and clinical utility of serum cryptococcal polysaccharide (CPS) antigen testing among HIV-infected patients in 2004 in Cambodia, an area highly endemic for cryptococcosis. METHODS: All HIV-infected patients with a CD4+ count <200 cells/mm3 attending 1 of 2 Phnom Penh hospitals for the first time were systematically screened for serum CPS. Patients with positive test results were further investigated to identify those with cryptococcal meningitis (CM), pulmonary cryptococcosis, or isolated positive cryptococcal antigenemia (IPCA). RESULTS: The median (interquartile range [IQR]) CD4+ count of 327 enrolled patients was 24 (IQR: 8 to 65) cells/mm3. The prevalence of cryptococcal infection was 59 (18.0%) of 327 cases, of which 41 were CM and 10 were IPCA. In the absence of serum CPS detection, 17 (28.8%) of 59 cryptococcal infections would have been missed on the day of consultation. In patients with no specific symptoms of meningoencephalitis, the prevalence of positive serum CPS detection was 32 (10.8%) of 295 cases. Countryside residence (adjusted odds ratio [AOR] = 3.6), headache (AOR = 3.2), body mass index <15.4 kg/m2 (AOR = 3.4), CD4+ count <50 cells/mm3 (AOR = 4.0), and male gender (marginally, AOR = 2.1) were all independently associated with a positive test results. CONCLUSION: Serum CPS screening among AIDS patients with a CD4+ count <100 cells/mm3 is useful in areas highly endemic for cryptococcosis, allowing early diagnosis and treatment of this opportunistic infection.


Assuntos
Infecções Oportunistas Relacionadas com a AIDS/diagnóstico , Infecções Oportunistas Relacionadas com a AIDS/epidemiologia , Antígenos de Fungos/sangue , Criptococose/diagnóstico , Criptococose/epidemiologia , Cryptococcus neoformans/imunologia , HIV , Infecções Oportunistas Relacionadas com a AIDS/sangue , Adulto , Biomarcadores/sangue , Índice de Massa Corporal , Contagem de Linfócito CD4 , Camboja/epidemiologia , Estudos de Coortes , Criptococose/sangue , Cryptococcus neoformans/isolamento & purificação , Diagnóstico Diferencial , Feminino , Cefaleia/patologia , Humanos , Masculino , Meningite Criptocócica/sangue , Meningite Criptocócica/epidemiologia , Prevalência , Estudos Prospectivos , Fatores de Risco
14.
J Craniofac Surg ; 17(5): 880-2, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17003615

RESUMO

Upper airway stenosis in patients with faciocraniosynostosis is very common and often severe. Mid-face advancement, either with a Le Fort III or concomitantly to a monobloc frontofacial advancement, may prevent a tracheotomy or result in its ablation. The amelioration of respiratory function appears to be much better if the mid-face advancement is combined with distraction osteogenesis, although large studies with long-term follow-up are rare. In this study we reviewed the respiratory outcome between Le Fort III with distraction and monobloc advancement with distraction in 55 faciocraniosynostotic patients. Early respiratory results of both procedures were very good and stable at long-term follow-up. The choice between a Le Fort III and a monobloc procedure is made based on presenting morphology, previous surgery, and age. Both can be expected to give a long-lasting improvement of upper airway obstruction.


Assuntos
Craniossinostoses/cirurgia , Maxila/cirurgia , Osteogênese por Distração/métodos , Osteotomia de Le Fort/métodos , Síndrome do Desconforto Respiratório/cirurgia , Adolescente , Criança , Pré-Escolar , Humanos , Lactente , Estudos Retrospectivos
15.
J Craniofac Surg ; 17(4): 642-4, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16877907

RESUMO

Upper airway stenosis in patients with faciocraniosynostosis is very common and often severe. Midface advancement, either with a Le Fort III or concomitantly to a monobloc frontofacial advancement, may prevent a tracheotomy or result in its ablation. The amelioration of respiratory function appears to be much better if the midface advancement is combined with distraction osteogenesis, although large studies with long-term follow-up are rare. In this study, we reviewed the respiratory outcome between Le Fort III with distraction and monobloc advancement with distraction in 54 faciocraniosynostotic patients. Early respiratory results of both procedures were very good and stable at long-term follow-up. The choice between a Le Fort III and a monobloc procedure is made on the basis of presenting morphology, previous surgery, and age. Both can be expected to give a long-lasting improvement of upper airway obstruction.


Assuntos
Maxila/cirurgia , Osteogênese por Distração/métodos , Osteotomia de Le Fort/métodos , Respiração , Acrocefalossindactilia/cirurgia , Adolescente , Fatores Etários , Obstrução das Vias Respiratórias/prevenção & controle , Criança , Pré-Escolar , Disostose Craniofacial/cirurgia , Craniossinostoses/cirurgia , Seguimentos , Humanos , Lactente , Estudos Longitudinais , Osteotomia de Le Fort/classificação , Reoperação , Estudos Retrospectivos , Traqueostomia , Resultado do Tratamento
16.
Mol Cell Biochem ; 254(1-2): 173-83, 2003 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-14674696

RESUMO

The biosynthesis of polyhydroxyalkanoates (PHAs) was studied, for the first time, in the thermophilic bacterium Thermus thermophilus. Using sodium gluconate (1.5% w/v) or sodium octanoate (10 mM) as sole carbon sources, PHAs were accumulated to approximately 35 or 40% of the cellular dry weight, respectively. Gas chromatographic analysis of PHA isolated from gluconate-grown cells showed that the polyester (Mw: 480,000 g mol(-1)) was mainly composed of 3-hydroxydecanoate (3HD) with a molar fraction of 64%. In addition, 3-hydroxyoctanoate (3HO), 3-hydroxyvalerate (3HV) and 3-hydroxybutyrate (3HB) occurred as constituents. In contrast, the polyester (Mw: 391,000 g mol(-1)) from octanoate-grown cells was composed of 24.5 mol% 3HB, 5.4 mol% 3HO, 12.3 mol% 3-hydroxynonanoate (3HN), 14.6 mol% 3HD, 35.4 mol% 3-hydroxyundecanoate (3HUD) and 7.8 mol% 3-hydroxydodecanoate (3HDD). Activities of PHA synthase, a beta-ketothiolase and an NADPH-dependent reductase were detected in the soluble cytosolic fraction obtained from gluconate-grown cells of T. thermophilus. The soluble PHA synthase was purified 4271-fold with 8.5% recovery from gluconate-grown cells, presenting a Km of 0.25 mM for 3HB-CoA. The optimal temperature of PHA synthase activity was about 70 degrees C and acts optimally at pH near 7.3. PHA synthase activity was inhibited 50% with 25 microM CoA and lost all of its activity when it was treated with alkaline phosphatase. T. thermophilus PHA synthase, in contrary to other reported PHA synthases did not exhibit a lag phase on its kinetics, when low concentration of the enzyme was used. Incubation of PHA synthase with 1 mM N-ethyl-maleimide inhibits the enzyme 56%, indicating that cysteine might be involved in the catalytic site of the enzyme. Acetyl phosphate (10 mM) activated both the native and the dephosphorylated enzyme. A major protein (55 kDa) was detected by SDS-PAGE. When a partially purified preparation was analyzed on native PAGE the major band exhibiting PHA synthase activity was eluted from the gel and analyzed further on SDS-PAGE, presenting the first purification of a PHA synthase from a thermophilic microorganism.


Assuntos
Aciltransferases/química , Aciltransferases/isolamento & purificação , Ácidos Carboxílicos/metabolismo , Poliésteres/metabolismo , Thermus thermophilus/metabolismo , Ácido 3-Hidroxibutírico/química , Acetil-CoA C-Aciltransferase/química , Acetil-CoA C-Aciltransferase/metabolismo , Fosfatase Alcalina/química , Fosfatase Alcalina/metabolismo , Caprilatos/química , Caprilatos/farmacologia , Carbono/química , Catálise , Domínio Catalítico , Cromatografia Gasosa , Cromatografia em Gel , Citosol/enzimologia , Citosol/metabolismo , Relação Dose-Resposta a Droga , Eletroforese em Gel de Poliacrilamida , Etilmaleimida/farmacologia , Gluconatos/química , Gluconatos/farmacologia , Concentração de Íons de Hidrogênio , Cinética , Microscopia Eletrônica de Varredura , NADP/metabolismo , Organofosfatos/química , Ácidos Pentanoicos/química , Fosforilação , Poliésteres/química , Temperatura , Fatores de Tempo
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