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1.
Qual Health Res ; 32(14): 2126-2146, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36350782

RESUMO

Over the last decade, youth have been acknowledged as agents of change in the fight against climate change, and more recently in disaster risk reduction. However, there is a need for improved opportunities for youth to participate and have their voices heard in both contexts. Our Photovoice study explores youth perceptions of the capability of youth to participate in disaster risk reduction and climate change action. We conducted six focus groups from February 2019 to June 2019 with four teenaged youth participants in Ottawa, Canada, hosting two virtual Photovoice exhibitions in 2021. Our results highlight 11 themes across a variety of topics including youth as assets, youth-adult partnerships, political action on consumerism, social media, education, accessibility, and art as knowledge translation. We provide four calls to action, centering youth participation and leadership across all of them, to guide stakeholders in how to improve disaster risk reduction and climate change initiatives by meaningfully including youth as stakeholders.


Assuntos
Desastres , Fotografação , Adulto , Adolescente , Humanos , Liderança , Comportamento de Redução do Risco , Canadá
2.
Qual Health Res ; 32(12): 1897-1906, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35938515

RESUMO

Community involvement is essential for an all-of-society approach to disaster risk reduction. This requires innovative consultation methods, particularly with youth and during pandemic restrictions. This article outlines methods used for a Photovoice project where we brought together student co-researchers from multiple levels (high school, undergraduate, and graduate health sciences) to explore the topic of youth engagement in disaster risk reduction. Over a two-year period, our team used Photovoice as an arts-based participatory method to collaborate with members of our EnRiCH Youth Research Team. We adapted the protocol to continue our project during the COVID-19 pandemic and presented our work in a Photovoice exhibition using Instagram. This article was written from the perspectives of high school and university students on the project. Our hybrid Photovoice protocol facilitated participation through the pandemic, including a virtual presentation at an international conference and online consultation with the Canadian Red Cross.


Assuntos
COVID-19 , Desastres , Adolescente , COVID-19/epidemiologia , COVID-19/prevenção & controle , Canadá , Pesquisa Participativa Baseada na Comunidade/métodos , Humanos , Pandemias/prevenção & controle , Fotografação , Comportamento de Redução do Risco
3.
Proc Biol Sci ; 287(1919): 20192446, 2020 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-31964301

RESUMO

Resource availability can powerfully influence host-parasite interactions. However, we currently lack a mechanistic framework to predict how resource fluctuations alter individual infection dynamics. We address this gap with experiments manipulating resource supply and starvation for a human parasite, Schistosoma mansoni, and its snail intermediate host to test a hypothesis derived from mechanistic energy budget theory: resource fluctuations should reduce schistosome reproduction and virulence by inhibiting parasite ingestion of host biomass. Low resource supply caused hosts to remain small, reproduce less and produce fewer human-infectious cercariae. Periodic starvation also inhibited cercarial production and prevented infection-induced castration. The periodic starvation experiment also revealed substantial differences in fit between two bioenergetic model variants, which differ in their representation of host starvation. Simulations using the best-fit parameters of the winning model suggest that schistosome performance substantially declines with resource fluctuations with periods greater than 7 days. These experiments strengthen mechanistic theory, which can be readily scaled up to the population level to understand key feedbacks between resources, host population dynamics, parasitism and control interventions. Integrating resources with other environmental drivers of disease in an explicit bioenergetic framework could ultimately yield mechanistic predictions for many disease systems.


Assuntos
Schistosoma mansoni/fisiologia , Caramujos/parasitologia , Animais , Interações Hospedeiro-Parasita , Humanos , Recursos Naturais , Parasitos
4.
PLoS Pathog ; 9(7): e1003468, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23853590

RESUMO

Distinct phylogenetic lineages of Mycobacterium tuberculosis (MTB) cause disease in patients of particular genetic ancestry, and elicit different patterns of cytokine and chemokine secretion when cultured with human macrophages in vitro. Circulating and antigen-stimulated concentrations of these inflammatory mediators might therefore be expected to vary significantly between tuberculosis patients of different ethnic origin. Studies to characterise such variation, and to determine whether it relates to host or bacillary factors, have not been conducted. We therefore compared circulating and antigen-stimulated concentrations of 43 inflammatory mediators and 14 haematological parameters (inflammatory profile) in 45 pulmonary tuberculosis patients of African ancestry vs. 83 patients of Eurasian ancestry in London, UK, and investigated the influence of bacillary and host genotype on these profiles. Despite having similar demographic and clinical characteristics, patients of differing ancestry exhibited distinct inflammatory profiles at presentation: those of African ancestry had lower neutrophil counts, lower serum concentrations of CCL2, CCL11 and vitamin D binding protein (DBP) but higher serum CCL5 concentrations and higher antigen-stimulated IL-1 receptor antagonist and IL-12 secretion. These differences associated with ethnic variation in host DBP genotype, but not with ethnic variation in MTB strain. Ethnic differences in inflammatory profile became more marked following initiation of antimicrobial therapy, and immunological correlates of speed of elimination of MTB from the sputum differed between patients of African vs. Eurasian ancestry. Our study demonstrates a hitherto unappreciated degree of ethnic heterogeneity in inflammatory profile in tuberculosis patients that associates primarily with ethnic variation in host, rather than bacillary, genotype. Candidate immunodiagnostics and immunological biomarkers of response to antimicrobial therapy should be derived and validated in tuberculosis patients of different ethnic origin.


Assuntos
Interações Hospedeiro-Patógeno , Mediadores da Inflamação/sangue , Mycobacterium tuberculosis/imunologia , Tuberculose Pulmonar/imunologia , Adulto , Antibióticos Antituberculose/uso terapêutico , Antígenos de Bactérias/metabolismo , Povo Asiático , Carga Bacteriana/efeitos dos fármacos , População Negra , Células Sanguíneas/imunologia , Células Sanguíneas/metabolismo , Células Cultivadas , Feminino , Interações Hospedeiro-Patógeno/efeitos dos fármacos , Humanos , Mediadores da Inflamação/metabolismo , Isoniazida/uso terapêutico , Londres , Masculino , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/isolamento & purificação , Escarro/efeitos dos fármacos , Escarro/microbiologia , Tuberculose Pulmonar/tratamento farmacológico , Tuberculose Pulmonar/etnologia , Tuberculose Pulmonar/virologia , População Branca , Adulto Jovem
5.
Graefes Arch Clin Exp Ophthalmol ; 253(9): 1479-83, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25367832

RESUMO

PURPOSE: To report the reproducibility, sensitivity, specificity, and predictive value of home monitoring for disease activity in neovascular age-related macular degeneration (ARMD). METHODS: Participants were trained to complete three separate home monitoring tasks, designed to identify subtle changes in visual function that may indicate increasing neovascular ARMD disease activity. These included measurement of near acuity and assessments of environmental distortion and overall visual function. The need for repeat intra-vitreal injection, as predicted by home monitoring, was compared to standard clinical assessment involving ETDRS distance acuity, slit lamp examination, and spectral domain ocular coherence tomography. RESULTS: Although all participants were able to complete the home monitoring tasks, the reproducibility of each of the three tasks was modest. Cohen's kappa was 0.118 (p = 0.54) for the comparison of the outcome of the home monitoring exercise with the gold standard of hospital assessment to determine disease activity. The sensitivity of the home monitoring exercise was 33.3 % (95 % CI 15.2-51.4) and the specificity was 77.8 % (95 % CI 61.8-93.8). CONCLUSIONS: This study suggests that current tests of visual function, which are readily completed at home, cannot replace traditional clinic-based assessments for neovascular ARMD disease activity. Instead, such tests are likely to remain complementary to standard assessment in clinic.


Assuntos
Inibidores da Angiogênese/uso terapêutico , Monitorização Ambulatorial , Ranibizumab/uso terapêutico , Transtornos da Visão/diagnóstico , Testes Visuais/normas , Degeneração Macular Exsudativa/diagnóstico , Idoso , Idoso de 80 Anos ou mais , Reações Falso-Positivas , Feminino , Humanos , Injeções Intravítreas , Quimioterapia de Manutenção , Masculino , Pessoa de Meia-Idade , Monitorização Ambulatorial/normas , Projetos Piloto , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Transtornos da Visão/tratamento farmacológico , Acuidade Visual/fisiologia , Degeneração Macular Exsudativa/tratamento farmacológico
6.
Proc Natl Acad Sci U S A ; 109(38): 15449-54, 2012 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-22949664

RESUMO

Calcidiol, the major circulating metabolite of vitamin D, supports induction of pleiotropic antimicrobial responses in vitro. Vitamin D supplementation elevates circulating calcidiol concentrations, and thus has a potential role in the prevention and treatment of infection. The immunomodulatory effects of administering vitamin D to humans with an infectious disease have not previously been reported. To characterize these effects, we conducted a detailed longitudinal study of circulating and antigen-stimulated immune responses in ninety-five patients receiving antimicrobial therapy for pulmonary tuberculosis who were randomized to receive adjunctive high-dose vitamin D or placebo in a clinical trial, and who fulfilled criteria for per-protocol analysis. Vitamin D supplementation accelerated sputum smear conversion and enhanced treatment-induced resolution of lymphopaenia, monocytosis, hypercytokinaemia, and hyperchemokinaemia. Administration of vitamin D also suppressed antigen-stimulated proinflammatory cytokine responses, but attenuated the suppressive effect of antimicrobial therapy on antigen-stimulated secretion of IL-4, CC chemokine ligand 5, and IFN-α. We demonstrate a previously unappreciated role for vitamin D supplementation in accelerating resolution of inflammatory responses during tuberculosis treatment. Our findings suggest a potential role for adjunctive vitamin D supplementation in the treatment of pulmonary infections to accelerate resolution of inflammatory responses associated with increased risk of mortality.


Assuntos
Tuberculose/imunologia , Vitamina D/metabolismo , Adulto , Peptídeos Catiônicos Antimicrobianos/farmacologia , Antituberculosos/farmacologia , Feminino , Regulação da Expressão Gênica , Genótipo , Humanos , Sistema Imunitário , Inflamação , Cinética , Masculino , Pessoa de Meia-Idade , Polimorfismo Genético , Análise de Regressão , Risco , Esteroides/química , Fatores de Tempo , Tuberculose/terapia , Vitamina D/uso terapêutico
7.
Anim Cogn ; 17(5): 1121-35, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24682709

RESUMO

Inhibition of return (IOR) is an important psychological construct describing inhibited responses to previously attended locations. In humans, it is investigated using Posner's cueing paradigm. This paradigm requires central visual fixation and detection of cued stimuli to the left or right of the fixation point. Stimuli can be validly or invalidly cued, appearing in the same or opposite location to the cue. Although a rat version of the spatial cueing paradigm (the covert orienting of attention task) does exist, IOR has so far not been demonstrated. We therefore investigated whether IOR could be robustly demonstrated in adult male rats using the covert orienting of attention task. This task is conducted in holed wall operant chambers with the central three holes mimicking the set-up for Posner cueing. Across four samples of rats (overall n = 84), we manipulated the following task parameters: stimulus onset asynchronies (Experiments 1-3), cue brightness (Experiment 1b) and the presence of a central reorienting event (Experiment 4). In Experiment 1, we also investigated strain differences by comparing Lister Hooded rats to Sprague-Dawley rats. Although Lister Hooded rats briefly showed evidence of IOR (Experiment 1a, and see Online Resource 1 data), we were unable to replicate this finding in our other experiments using different samples of this strain. Taken together, our findings suggest that IOR cannot be robustly demonstrated in the rat using the covert orienting of attention task conducted in holed wall operant chambers.


Assuntos
Atenção , Inibição Psicológica , Animais , Condicionamento Operante , Sinais (Psicologia) , Fixação Ocular , Masculino , Estimulação Luminosa , Ratos , Ratos Wistar/psicologia
8.
Behav Ecol ; 35(5): arae054, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39034972

RESUMO

Despite Batesian mimicry often eliciting predator avoidance, many Batesian mimics, such as some species of hoverfly (Syrphidae), are considered to have an "imperfect" resemblance to their model. One possible explanation for the persistence of apparently imperfect mimicry is that human perceptions of mimicry are different from those of natural predators. Natural predators of hoverflies have different visual and cognitive systems from humans, and they may encounter mimics in a different way. For example, whilst humans often encounter hoverflies at rest on vegetation, or in photographs or textbooks, where they are typically viewed from above, natural predators may approach hoverflies from the side or below. To test how viewing angle affects the perception of mimicry, images of mimetic hoverflies and their models (wasps and bees) were shown from different angles in an online survey. Participants were asked to distinguish between the images of models and mimics. The results show that the viewing angle does affect perceived mimicry in some species, although it does not provide a complete explanation for the persistence of imperfect mimicry in nature. The effect is also highly species-specific. This suggests that to understand better how selection has shaped mimetic accuracy in hoverflies and other taxa, further study is required of the viewing angles that predators utilize most commonly in nature.

9.
Artigo em Inglês | MEDLINE | ID: mdl-37595630

RESUMO

BACKGROUND: Hemostasis in neurosurgery is crucial to patient and surgery outcomes, with many techniques developed for this. One area that is not appropriately characterized despite continuous anecdotal evidence the temperature of the irrigation fluid (IF) used and its effects on stemming hemorrhages. Given the ubiquitous use of IF in neurosurgery for clearing blood from the surgical field, it is important to explore its role as a hemostat and whether or not the temperature of the IF influences its hemostatic capacity. This review explored the literature for an optimal IF temperature for hemostasis in neurosurgery. METHODS: Database searches were conducted using MEDLINE, Scopus, Web of Science, and CINAHL, with citation chaining occurring where applicable. Standard terms around neurosurgery, hemostasis, and irrigation were used. RESULTS: Seven articles were identified. No optimal temperature for hemostasis could be confidently synthesized from the literature owing to lack of primary investigation on the subject. After collating available information into common themes, it is suggested that that temperatures >38°C are preferred. CONCLUSION: The literature in this area is limited. Despite a lack of applicable systematic investigation on the topic, by exploring the physiology of hemostasis and IF, best practice guidelines for IF, and the literature on the role of the temperature of IF in other surgical specialties, it is suggested that a temperature in the range of 38 to 40°C would be most applicable to a value optimal for neurosurgery.

10.
Lancet ; 377(9761): 242-50, 2011 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-21215445

RESUMO

BACKGROUND: Vitamin D was used to treat tuberculosis in the pre-antibiotic era, and its metabolites induce antimycobacterial immunity in vitro. Clinical trials investigating the effect of adjunctive vitamin D on sputum culture conversion are absent. METHODS: We undertook a multicentre randomised controlled trial of adjunctive vitamin D in adults with sputum smear-positive pulmonary tuberculosis in London, UK. 146 patients were allocated to receive 2·5 mg vitamin D(3) or placebo at baseline and 14, 28, and 42 days after starting standard tuberculosis treatment. The primary endpoint was time from initiation of antimicrobial treatment to sputum culture conversion. Patients were genotyped for TaqI and FokI polymorphisms of the vitamin D receptor, and interaction analyses were done to assess the influence of the vitamin D receptor genotype on response to vitamin D(3). This trial is registered with ClinicalTrials.gov number NCT00419068. FINDINGS: 126 patients were included in the primary efficacy analysis (62 assigned to intervention, 64 assigned to placebo). Median time to sputum culture conversion was 36·0 days in the intervention group and 43·5 days in the placebo group (adjusted hazard ratio 1·39, 95% CI 0·90-2·16; p=0.14). TaqI genotype modified the effect of vitamin D supplementation on time to sputum culture conversion (p(interaction)=0·03), with enhanced response seen only in patients with the tt genotype (8·09, 95% CI 1·36-48·01; p=0·02). FokI genotype did not modify the effect of vitamin D supplementation (p(interaction)=0·85). Mean serum 25-hydroxyvitamin D concentration at 56 days was 101·4 nmol/L in the intervention group and 22·8 nmol/L in the placebo group (95% CI for difference 68·6-88·2; p<0·0001). INTERPRETATION: Administration of four doses of 2·5 mg vitamin D(3) increased serum 25-hydroxyvitamin D concentrations in patients receiving intensive-phase treatment for pulmonary tuberculosis. Vitamin D did not significantly affect time to sputum culture conversion in the whole study population, but it did significantly hasten sputum culture conversion in participants with the tt genotype of the TaqI vitamin D receptor polymorphism. FUNDING: British Lung Foundation.


Assuntos
Antituberculosos/uso terapêutico , Colecalciferol/administração & dosagem , Tuberculose Pulmonar/tratamento farmacológico , Vitaminas/administração & dosagem , Adulto , Método Duplo-Cego , Feminino , Humanos , Masculino , Polimorfismo Genético , Receptores de Calcitriol/genética , Escarro/microbiologia , Taq Polimerase/genética , Adulto Jovem
11.
Neurosci Biobehav Rev ; 143: 104925, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36283539

RESUMO

Our study estimated size of impairment for different cognitive functions in early-treated adults with PKU (AwPKU) by combining literature results in a meta-analytic way. We analysed a large set of functions (N = 19), each probed by different measures (average = 12). Data were extracted from 26 PKU groups and matched controls, with 757 AwPKU contributing 220 measures. Effect sizes (ESs) were computed using Glass' ∆ where differences in performance between clinical/PKU and control groups are standardized using the mean and standard deviation of the control groups. Significance was assessed using measures nested within independent PKU groups as a random factor. The weighted Glass' ∆ was - 0.44 for all functions taken together, and - 0.60 for IQ, both highly significant. Separate, significant impairments were found for most functions, but with great variability (ESs from -1.02 to -0.18). The most severe impairments were in reasoning, visual-spatial attention speed, sustained attention, visuo-motor control, and flexibility. Effect sizes were larger with speed than accuracy measures, and with visuo-spatial than verbal stimuli. Results show a specific PKU profile that needs consideration when monitoring the disease.


Assuntos
Cognição , Fenilcetonúrias , Adulto , Humanos , Atenção , Testes Neuropsicológicos , Fenilcetonúrias/psicologia , Resolução de Problemas
12.
Int J Disaster Risk Reduct ; 83: 103420, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36373152

RESUMO

Youth engagement in disaster risk reduction is a growing area of research, practice and policy. The COVID-19 pandemic highlighted the need for improved opportunities for youth to participate and have their voices heard. Our Photovoice study explores experiences, perceptions, and insights of youth regarding the COVID-19 pandemic, while providing an opportunity for youth to participate in disaster risk reduction and contribute to resilient communities. We conducted nine focus groups from February 2019 to August 2020 with four teenaged youth; we analyzed the data using reflexive thematic analysis and hosted two virtual Photovoice exhibitions. Our results explore youth experiences of public health measures, impacts of the pandemic, pandemic magnification of social inequities, and the power of youth to create change. We provide six calls to action, focusing on a holistic, upstream, all-of-society approach for stakeholders to collaborate with youth in creating change on complex social justice issues to support COVID-19 recovery.

13.
Eur Arch Otorhinolaryngol ; 267(4): 643-5, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19690879

RESUMO

With training time for junior doctors now reduced, it is crucial to optimise training opportunities during elective clinical activities. Teaching ENT examination skills presents unique challenges as often, only the examiner can observe what's going on. We set out to explore the utilisation of microscope and nasendoscope teaching devices for ENT junior doctors. Telephonic survey of 102 English ENT units. ENT junior doctors spent an average of 7 h per week in elective ENT outpatient clinics. 92% of them felt that spending time in outpatient clinics helped improve their confidence in patients' management. 81% of ENT junior doctors stated that being able to observe others or being observed themselves would help to improve their clinical abilities. The availability and utilisation of nasendoscopy and microscopy teaching tools are currently suboptimal. Doctors working in departments that utilised the teaching tools stated that their educational needs were more likely to be met. Most ENT junior doctors found it beneficial to attend elective outpatient clinics although their learning needs were more likely to be met should ENT teaching devices be available. The availability and utilisation of ENT teaching devices are currently suboptimal and needs addressing.


Assuntos
Tecnologia de Fibra Óptica/instrumentação , Microscopia/instrumentação , Otolaringologia/instrumentação , Otolaringologia/métodos , Ensino/métodos , Educação Médica , Humanos , Inquéritos e Questionários
14.
Popul Trends ; (116): 6-10, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15272622

RESUMO

This article discusses early thinking on the options for the population bases to be used in the 2011 Census. It describes some of the work being conducted to enable a decision about bases to be reached, including historic and international reviews of censuses. It also discusses the implications that our rapidly changing society has for census planning.


Assuntos
Censos , Coleta de Dados/métodos , Estatísticas Vitais , Tomada de Decisões Gerenciais , Humanos , Política Pública , Reino Unido/epidemiologia
15.
Menopause Int ; 18(2): 73-6, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22611226

RESUMO

Non-hormonal approaches to premenstrual syndrome (PMS) treatment such as selective serotonin reuptake inhibitors are by no means effective for all women and frequently we must resort to endocrine therapy. During many of the hormonal approaches, PMS-like symptoms can be introduced or re-introduced during the necessary cyclical or continuous progestogen component of the therapy. This is seen with combined oral contraception, progestogen only contraception, progestogen therapy for heavy menstrual bleeding and endometriosis, sequential hormone replacement therapy and any therapeutic strategy for premenstrual syndrome where it is necessary to provide endometrial protection, including estrogen suppression of ovulation or add-back during gonadotrophin releasing hormone suppression. The link to progestogen is very often missed by health professionals. When the pattern of symptoms mimics the cyclicity of PMS, it is termed progestogen-induced premenstrual disorder. The need to use progestogen to protect the endometrium from the proliferative actions of estrogen can pose insurmountable difficulties in managing premenstrual disorders. In the absence of any really useful evidence, nearly all practice in this area depends on clinician experience. We cannot afford to wait for adequate research evidence to be produced - it never will - and so we must rely on empirical findings, clinical experience, theoretical strategies and common sense.


Assuntos
Síndrome Pré-Menstrual/induzido quimicamente , Síndrome Pré-Menstrual/terapia , Progestinas/efeitos adversos , Anticoncepcionais Orais Hormonais/efeitos adversos , Relação Dose-Resposta a Droga , Estrogênios/uso terapêutico , Feminino , Hormônio Liberador de Gonadotropina/análogos & derivados , Hormônio Liberador de Gonadotropina/uso terapêutico , Terapia de Reposição Hormonal/efeitos adversos , Humanos , Histerectomia , Ciclo Menstrual , Inibidores Seletivos de Recaptação de Serotonina/uso terapêutico
16.
Biol Lett ; 2(1): 26-8, 2006 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-17148317

RESUMO

An important area of biology involves investigating the origins in animals of traits that are thought of as uniquely human. One way that humans appear unique is in the importance they attach to the dead bodies of other humans, particularly those of their close kin, and the rituals that they have developed for burying them. In contrast, most animals appear to show only limited interest in the carcasses or associated remains of dead individuals of their own species. African elephants (Loxodonta africana) are unusual in that they not only give dramatic reactions to the dead bodies of other elephants, but are also reported to systematically investigate elephant bones and tusks that they encounter, and it has sometimes been suggested that they visit the bones of relatives. Here, we use systematic presentations of object arrays to demonstrate that African elephants show higher levels of interest in elephant skulls and ivory than in natural objects or the skulls of other large terrestrial mammals. However, they do not appear to specifically select the skulls of their own relatives for investigation so that visits to dead relatives probably result from a more general attraction to elephant remains.


Assuntos
Comportamento Animal , Elefantes/psicologia , Crânio , África , Animais , Especificidade da Espécie
17.
Appl Environ Microbiol ; 71(12): 8207-13, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16332804

RESUMO

The phylogeny and evolution of the bacterium Mycobacterium tuberculosis is still poorly understood despite the application of a variety of molecular techniques. We analyzed 469 M. tuberculosis and 49 Mycobacterium bovis isolates to evaluate if the mycobacterial interspersed repetitive units-variable-number tandem repeats (MIRU-VNTR) commonly used for epidemiological studies can define the phylogeny of the M. tuberculosis complex. This population was characterized by previously identified silent single-nucleotide polymorphisms (sSNPs) or by a macroarray based on these sSNPs that was developed in this study. MIRU-VNTR phylogenetic codes capable of differentiating between phylogenetic lineages were identified. Overall, there was 90.9% concordance between the lineages of isolates as defined by the MIRU-VNTR and sSNP analyses. The MIRU-VNTR phylogenetic code was unique to M. bovis and was not observed in any M. tuberculosis isolates. The codes were able to differentiate between different M. tuberculosis strain families such as Beijing, Delhi, and East African-Indian. Discrepant isolates with similar but not identical MIRU-VNTR codes often displayed a stepwise trend suggestive of bidirectional evolution. A lineage-specific panel of MIRU-VNTR can be used to subdivide each lineage for epidemiological purposes. MIRU-VNTR is a valuable tool for phylogenetic studies and could define an evolutionarily uncharacterized population of M. tuberculosis complex organisms.


Assuntos
Evolução Molecular , Sequências Repetitivas Dispersas/genética , Mycobacterium bovis/genética , Mycobacterium tuberculosis/genética , Sequência de Bases , Primers do DNA , Sondas de DNA , Repetições Minissatélites , Mycobacterium bovis/classificação , Análise de Sequência com Séries de Oligonucleotídeos , Filogenia , Reprodutibilidade dos Testes
18.
Emerg Infect Dis ; 10(9): 1568-77, 2004 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15498158

RESUMO

Much remains unknown of the phylogeny and evolution of Mycobacterium tuberculosis, an organism that kills 2 million people annually. Using a population-based approach that analyzes multiple loci around the chromosome, we demonstrate that neutral genetic variation in genes associated with antimicrobial drug resistance has sufficient variation to construct a robust phylogenetic tree for M. tuberculosis. The data describe a clonal population with a minimum of four distinct M. tuberculosis lineages, closely related to M. bovis. The lineages are strongly geographically associated. Nucleotide substitutions proven to cause drug resistance are distributed throughout the tree, whereas nonsynonymous base substitutions unrelated to drug resistance have a restricted distribution. The phylogenetic structure is concordant with all the previously described genotypic and phenotypic groupings of M. tuberculosis strains and provides a unifying framework for both epidemiologic and evolutionary analysis of M. tuberculosis populations.


Assuntos
Mycobacterium tuberculosis/genética , Amidoidrolases/genética , Antituberculosos/farmacologia , Proteínas de Bactérias/genética , Sequência de Bases , Catalase/genética , Impressões Digitais de DNA , DNA Girase/genética , RNA Polimerases Dirigidas por DNA/genética , Farmacorresistência Bacteriana Múltipla/genética , Evolução Molecular , Variação Genética , Dados de Sequência Molecular , Filogenia , Polimorfismo de Nucleotídeo Único , Proteínas Ribossômicas/genética , Alinhamento de Sequência , Análise de Sequência de DNA
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