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1.
Musculoskelet Sci Pract ; 72: 102930, 2024 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-38552401

RESUMO

BACKGROUND: The coronavirus (COVID-19) pandemic resulted in the rapid implementation of remote consultations to maintain musculoskeletal physiotherapy services. However, little is known about UK musculoskeletal physiotherapists' experiences of providing services during the COVID-19 pandemic. OBJECTIVES: To explore musculoskeletal physiotherapists' experiences of using remote consultations in one area of England during the COVID-19 pandemic. DESIGN: Qualitative study using hermeneutic phenomenology based on the approach of Gadamer. METHODS: Semi-structured interviews with twelve musculoskeletal physiotherapists were conducted online using Microsoft Teams. Data were analysed using frameworks based on the philosophical concepts of Gadamer's hermeneutics. FINDINGS: Musculoskeletal physiotherapists' experience of using remote consultations during the COVID-19 pandemic was framed by three concepts: therapeutic relationship, transformational change, and uncertainty. These concepts are underpinned by four main themes capturing their experiences: (1) Disconnection: Difficulties building a rapport and reduced non-verbal communication affected building an effective therapeutic relationship, (2) Necessity: Transformation of services to remote consultations was positive, although technology and connectivity issues had a negative impact, (3) Loss of control: Diagnostic uncertainty, being unprepared, and experience affected physiotherapists' clinical practice, (4) Protection: Peer support and the use of technology facilitated a feeling of protection for physiotherapists. CONCLUSION: The findings of this study contribute to a better understanding of musculoskeletal physiotherapists' experience of using remote consultations during the COVID-19 pandemic. Implications for practice include the need to provide training for all musculoskeletal physiotherapists and undergraduates to enable the effective delivery of remote physiotherapy. Furthermore, digital infrastructure should be optimised to support future delivery of remote musculoskeletal physiotherapy services.

2.
JMIR Res Protoc ; 12: e42965, 2023 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-36729586

RESUMO

BACKGROUND: Despite efforts, the UK death rate from asthma is the highest in Europe, and 65% of people with asthma in the United Kingdom do not receive the professional care they are entitled to. Experts have recommended the use of digital innovations to help address the issues of poor outcomes and lack of care access. An automated SMS text messaging-based conversational agent (ie, chatbot) created to provide access to asthma support in a familiar format via a mobile phone has the potential to help people with asthma across demographics and at scale. Such a chatbot could help improve the accuracy of self-assessed risk, improve asthma self-management, increase access to professional care, and ultimately reduce asthma attacks and emergencies. OBJECTIVE: The aims of this study are to determine the feasibility and usability of a text-based conversational agent that processes a patient's text responses and short sample voice recordings to calculate an estimate of their risk for an asthma exacerbation and then offers follow-up information for lowering risk and improving asthma control; assess the levels of engagement for different groups of users, particularly those who do not access professional services and those with poor asthma control; and assess the extent to which users of the chatbot perceive it as helpful for improving their understanding and self-management of their condition. METHODS: We will recruit 300 adults through four channels for broad reach: Facebook, YouGov, Asthma + Lung UK social media, and the website Healthily (a health self-management app). Participants will be screened, and those who meet inclusion criteria (adults diagnosed with asthma and who use WhatsApp) will be provided with a link to access the conversational agent through WhatsApp on their mobile phones. Participants will be sent scheduled and randomly timed messages to invite them to engage in dialogue about their asthma risk during the period of study. After a data collection period (28 days), participants will respond to questionnaire items related to the quality of the interaction. A pre- and postquestionnaire will measure asthma control before and after the intervention. RESULTS: This study was funded in March 2021 and started in January 2022. We developed a prototype conversational agent, which was iteratively improved with feedback from people with asthma, asthma nurses, and specialist doctors. Fortnightly reviews of iterations by the clinical team began in September 2022 and are ongoing. This feasibility study will start recruitment in January 2023. The anticipated completion of the study is July 2023. A future randomized controlled trial will depend on the outcomes of this study and funding. CONCLUSIONS: This feasibility study will inform a follow-up pilot and larger randomized controlled trial to assess the impact of a conversational agent on asthma outcomes, self-management, behavior change, and access to care. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/42965.

3.
Proc Natl Acad Sci U S A ; 119(15): e2120003119, 2022 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-35377795

RESUMO

Lymphatic filariasis is a vector-borne neglected tropical disease prioritized for global elimination. The filarial nematodes that cause the disease host a symbiotic bacterium, Wolbachia, which has been targeted using antibiotics, leading to cessation of parasite embryogenesis, waning of circulating larvae (microfilariae [mf]), and gradual cure of adult infection. One of the benefits of the anti-Wolbachia mode of action is that it avoids the rapid killing of mf, which can drive inflammatory adverse events. However, mf depleted of Wolbachia persist for several months in circulation, and thus patients treated with antibiotics are assumed to remain at risk for transmitting infections. Here, we show that Wolbachia-depleted mf rapidly lose the capacity to develop in the mosquito vector through a defect in exsheathment and inability to migrate through the gut wall. Transcriptomic and Western blotting analyses demonstrate that chitinase, an enzyme essential for mf exsheathment, is down-regulated in Wolbachia-depleted mf and correlates with their inability to exsheath and escape the mosquito midgut. Supplementation of in vitro cultures of Wolbachia-depleted mf with chitinase enzymes restores their ability to exsheath to a similar level to that observed in untreated mf. Our findings elucidate a mechanism of rapid transmission-blocking activity of filariasis after depletion of Wolbachia and adds to the broad range of biological processes of filarial nematodes that are dependent on Wolbachia symbiosis.


Assuntos
Antibacterianos , Quitinases , Filariose Linfática , Microfilárias , Wolbachia , Animais , Antibacterianos/farmacologia , Quitinases/genética , Filariose Linfática/transmissão , Humanos , Microfilárias/enzimologia , Microfilárias/crescimento & desenvolvimento , Microfilárias/microbiologia , Mosquitos Vetores/parasitologia , Wolbachia/efeitos dos fármacos , Wolbachia/genética
4.
PLoS Negl Trop Dis ; 15(10): e0009838, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34705823

RESUMO

The sequence diversity of natural and laboratory populations of Brugia pahangi and Brugia malayi was assessed with Illumina resequencing followed by mapping in order to identify single nucleotide variants and insertions/deletions. In natural and laboratory Brugia populations, there is a lack of sequence diversity on chromosome X relative to the autosomes (πX/πA = 0.2), which is lower than the expected (πX/πA = 0.75). A reduction in diversity is also observed in other filarial nematodes with neo-X chromosome fusions in the genera Onchocerca and Wuchereria, but not those without neo-X chromosome fusions in the genera Loa and Dirofilaria. In the species with neo-X chromosome fusions, chromosome X is abnormally large, containing a third of the genetic material such that a sizable portion of the genome is lacking sequence diversity. Such profound differences in genetic diversity can be consequential, having been associated with drug resistance and adaptability, with the potential to affect filarial eradication.


Assuntos
Brugia/genética , Variação Genética , Cromossomo X/genética , Animais , Brugia/classificação , Aberrações Cromossômicas , Genoma Helmíntico
5.
ACS Med Chem Lett ; 12(9): 1421-1426, 2021 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-34527179

RESUMO

Anti-Wolbachia therapy has been identified as a viable treatment for combating filarial diseases. Phenotypic screening revealed a series of pyrazolopyrimidine hits with potent anti-Wolbachia activity. This paper focuses on the exploration of the SAR for this chemotype, with improvement of metabolic stability and solubility profiles using medicinal chemistry approaches. Organic synthesis has enabled functionalization of the pyrazolopyrimidine core at multiple positions, generating a library of compounds of which many analogues possess nanomolar activity against Wolbachia in vitro with improved DMPK parameters. A lead compound, 15f, was selected for in vivo pharmacokinetics (PK) profiling in mice. The combination of potent anti-Wolbachia activity in two in vitro assessments plus the exceptional oral PK profiles in mice puts this lead compound in a strong position for in vivo proof-of-concept pharmacodynamics studies and demonstrates the strong potential for further optimization and development of this series for treatment of filariasis in the future.

6.
Nat Chem ; 13(2): 140-148, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33380742

RESUMO

Finding faster and simpler ways to screen protein sequence space to enable the identification of new biocatalysts for asymmetric synthesis remains both a challenge and a rate-limiting step in enzyme discovery. Biocatalytic strategies for the synthesis of chiral amines are increasingly attractive and include enzymatic asymmetric reductive amination, which offers an efficient route to many of these high-value compounds. Here we report the discovery of over 300 new imine reductases and the production of a large (384 enzymes) and sequence-diverse panel of imine reductases available for screening. We also report the development of a facile high-throughput screen to interrogate their activity. Through this approach we identified imine reductase biocatalysts capable of accepting structurally demanding ketones and amines, which include the preparative synthesis of N-substituted ß-amino ester derivatives via a dynamic kinetic resolution process, with excellent yields and stereochemical purities.


Assuntos
Ensaios de Triagem em Larga Escala/métodos , Oxirredutases/isolamento & purificação , Aminação/efeitos dos fármacos , Aminas/química , Biocatálise , Iminas/metabolismo , Cetonas/química , Oxirredutases/metabolismo , Estereoisomerismo
7.
Adv Protein Chem Struct Biol ; 122: 289-320, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32951814

RESUMO

Cytochromes P450 (P450s) are a large superfamily of heme-containing monooxygenases. P450s are found in all Kingdoms of life and exhibit incredible diversity, both at sequence level and also on a biochemical basis. In the majority of cases, P450s can be assigned into one of ten classes based on their associated redox partners, domain architecture and cellular localization. Prokaryotic P450s now represent a large diverse collection of annotated/known enzymes, of which many have great potential biocatalytic potential. The self-sufficient P450 classes (Class VII/VIII) have been explored significantly over the past decade, with many annotated and biochemically characterized members. It is clear that the prokaryotic P450 world is expanding rapidly, as the number of published genomes and metagenome studies increases, and more P450 families are identified and annotated (CYP families).


Assuntos
Archaea , Bactérias , Sistema Enzimático do Citocromo P-450 , Genoma Arqueal , Genoma Bacteriano , Archaea/enzimologia , Archaea/genética , Bactérias/enzimologia , Bactérias/genética , Sistema Enzimático do Citocromo P-450/classificação , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Anotação de Sequência Molecular
8.
Sci Transl Med ; 11(483)2019 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-30867321

RESUMO

There is an urgent global need for a safe macrofilaricide drug to accelerate elimination of the neglected tropical diseases onchocerciasis and lymphatic filariasis. From an anti-infective compound library, the macrolide veterinary antibiotic, tylosin A, was identified as a hit against Wolbachia This bacterial endosymbiont is required for filarial worm viability and fertility and is a validated target for macrofilaricidal drugs. Medicinal chemistry was undertaken to develop tylosin A analogs with improved oral bioavailability. Two analogs, A-1535469 and A-1574083, were selected. Their efficacy was tested against the gold-standard second-generation tetracycline antibiotics, doxycycline and minocycline, in mouse and gerbil infection models of lymphatic filariasis (Brugia malayi and Litomosoides sigmodontis) and onchocerciasis (Onchocerca ochengi). A 1- or 2-week course of oral A-1535469 or A-1574083 provided >90% Wolbachia depletion from nematodes in infected animals, resulting in a block in embryogenesis and depletion of microfilarial worm loads. The two analogs delivered comparative or superior efficacy compared to a 3- to 4-week course of doxycycline or minocycline. A-1574083 (now called ABBV-4083) was selected for further preclinical testing. Cardiovascular studies in dogs and toxicology studies in rats and dogs revealed no adverse effects at doses (50 mg/kg) that achieved plasma concentrations >10-fold above the efficacious concentration. A-1574083 (ABBV-4083) shows potential as an anti-Wolbachia macrolide with an efficacy, pharmacology, and safety profile that is compatible with a short-term oral drug course for treating lymphatic filariasis and onchocerciasis.


Assuntos
Filariose Linfática/tratamento farmacológico , Filariose Linfática/microbiologia , Macrolídeos/administração & dosagem , Macrolídeos/uso terapêutico , Oncocercose/tratamento farmacológico , Oncocercose/microbiologia , Wolbachia/fisiologia , Administração Oral , Animais , Modelos Animais de Doenças , Filariose Linfática/sangue , Feminino , Macrolídeos/efeitos adversos , Masculino , Camundongos Endogâmicos BALB C , Camundongos SCID , Oncocercose/sangue , Resultado do Tratamento , Tilosina/sangue , Tilosina/síntese química , Tilosina/química , Tilosina/uso terapêutico
9.
J Med Chem ; 62(5): 2521-2540, 2019 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-30730745

RESUMO

A series of pleuromutilins modified by introduction of a boron-containing heterocycle on C(14) of the polycyclic core are described. These analogs were found to be potent anti- Wolbachia antibiotics and, as such, may be useful in the treatment of filarial infections caused by Onchocerca volvulus, resulting in Onchocerciasis or river blindness, or Wuchereria bancrofti and Brugia malayi and related parasitic nematodes resulting in lymphatic filariasis. These two important neglected tropical diseases disproportionately impact patients in the developing world. The lead preclinical candidate compound containing 7-fluoro-6-oxybenzoxaborole (15, AN11251) was shown to have good in vitro anti- Wolbachia activity and physicochemical and pharmacokinetic properties providing high exposure in plasma. The lead was effective in reducing the Wolbachia load in filarial worms following oral administration to mice.


Assuntos
Boro/farmacologia , Diterpenos/farmacologia , Filariose Linfática/tratamento farmacológico , Filaricidas/uso terapêutico , Oncocercose/tratamento farmacológico , Compostos Policíclicos/farmacologia , Wolbachia/efeitos dos fármacos , Wuchereria bancrofti/efeitos dos fármacos , Animais , Boro/química , Diterpenos/química , Filaricidas/farmacocinética , Filaricidas/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos SCID , Compostos Policíclicos/química
10.
Proc Natl Acad Sci U S A ; 116(4): 1414-1419, 2019 01 22.
Artigo em Inglês | MEDLINE | ID: mdl-30617067

RESUMO

Onchocerciasis and lymphatic filariasis are two neglected tropical diseases that together affect ∼157 million people and inflict severe disability. Both diseases are caused by parasitic filarial nematodes with elimination efforts constrained by the lack of a safe drug that can kill the adult filaria (macrofilaricide). Previous proof-of-concept human trials have demonstrated that depleting >90% of the essential nematode endosymbiont bacterium, Wolbachia, using antibiotics, can lead to permanent sterilization of adult female parasites and a safe macrofilaricidal outcome. AWZ1066S is a highly specific anti-Wolbachia candidate selected through a lead optimization program focused on balancing efficacy, safety and drug metabolism/pharmacokinetic (DMPK) features of a thienopyrimidine/quinazoline scaffold derived from phenotypic screening. AWZ1066S shows superior efficacy to existing anti-Wolbachia therapies in validated preclinical models of infection and has DMPK characteristics that are compatible with a short therapeutic regimen of 7 days or less. This candidate molecule is well-positioned for onward development and has the potential to make a significant impact on communities affected by filariasis.


Assuntos
Antibacterianos/farmacologia , Wolbachia/efeitos dos fármacos , Animais , Filariose Linfática/tratamento farmacológico , Filariose Linfática/microbiologia , Feminino , Masculino , Camundongos , Camundongos SCID , Oncocercose/tratamento farmacológico , Oncocercose/microbiologia , Pirimidinas/farmacologia , Quinazolinas/farmacologia
11.
Nat Commun ; 10(1): 11, 2019 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-30602718

RESUMO

Nematodes causing lymphatic filariasis and onchocerciasis rely on their bacterial endosymbiont, Wolbachia, for survival and fecundity, making Wolbachia a promising therapeutic target. Here we perform a high-throughput screen of AstraZeneca's 1.3 million in-house compound library and identify 5 novel chemotypes with faster in vitro kill rates (<2 days) than existing anti-Wolbachia drugs that cure onchocerciasis and lymphatic filariasis. This industrial scale anthelmintic neglected tropical disease (NTD) screening campaign is the result of a partnership between the Anti-Wolbachia consortium (A∙WOL) and AstraZeneca. The campaign was informed throughout by rational prioritisation and triage of compounds using cheminformatics to balance chemical diversity and drug like properties reducing the chance of attrition from the outset. Ongoing development of these multiple chemotypes, all with superior time-kill kinetics than registered antibiotics with anti-Wolbachia activity, has the potential to improve upon the current therapeutic options and deliver improved, safer and more selective macrofilaricidal drugs.


Assuntos
Descoberta de Drogas , Filaricidas/análise , Ensaios de Triagem em Larga Escala , Aedes , Animais , Linhagem Celular , Wolbachia
12.
Gates Open Res ; 3: 1734, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-32596646

RESUMO

Background:  Results from an increasing number of studies suggest that mosquito excreta/feces (E/F) testing has considerable potential to serve as a supplement for traditional molecular xenomonitoring techniques. However, as the catalogue of possible use-cases for this methodology expands, and the list of amenable pathogens grows, a number of fundamental methods-based questions remain. Answering these questions is critical to maximizing the utility of this approach and to facilitating its successful implementation as an effective tool for molecular xenomonitoring. Methods:  Utilizing E/F produced by mosquitoes or tsetse flies experimentally exposed to Brugia malayi, Plasmodium falciparum, or Trypanosoma brucei brucei, factors such as limits of detection, throughput of testing, adaptability to use with competent- and incompetent-vector species, and effects of additional blood feedings post parasite-exposure were evaluated.  Two platforms for the detection of pathogen signal (quantitative real-time PCR and digital PCR [dPCR]) were also compared, with strengths and weaknesses examined for each.       Results:  Experimental results indicated that high throughput testing is possible when evaluating mosquito E/F for the presence of either B. malayi or P. falciparum from both competent- and incompetent-vector mosquito species.  Furthermore, following exposure to pathogen, providing mosquitoes with a second, uninfected bloodmeal did not expand the temporal window for E/F collection during which pathogen detection was possible.  However, this collection window did appear longer in E/F collected from tsetse flies following exposure to T. b. brucei.  Testing also suggested that dPCR may facilitate detection through its increased sensitivity.  Unfortunately, logistical obstacles will likely make the large-scale use of dPCR impractical for this purpose. Conclusions:  By examining many E/F testing variables, expansion of this technology to a field-ready platform has become increasingly feasible.  However, translation of this methodology from the lab to the field will first require the completion of field-based pilot studies aimed at assessing the efficacy of E/F screening.

13.
PLoS Pathog ; 14(3): e1006949, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29547639

RESUMO

Eosinophils are effectors in immunity to tissue helminths but also induce allergic immunopathology. Mechanisms of eosinophilia in non-mucosal tissues during infection remain unresolved. Here we identify a pivotal function of tissue macrophages (Mϕ) in eosinophil anti-helminth immunity using a BALB/c mouse intra-peritoneal Brugia malayi filarial infection model. Eosinophilia, via C-C motif chemokine receptor (CCR)3, was necessary for immunity as CCR3 and eosinophil impairments rendered mice susceptible to chronic filarial infection. Post-infection, peritoneal Mϕ populations proliferated and became alternatively-activated (AAMϕ). Filarial AAMϕ development required adaptive immunity and interleukin-4 receptor-alpha. Depletion of Mϕ prior to infection suppressed eosinophilia and facilitated worm survival. Add back of filarial AAMϕ in Mϕ-depleted mice recapitulated a vigorous eosinophilia. Transfer of filarial AAMϕ into Severe-Combined Immune Deficient mice mediated immunological resistance in an eosinophil-dependent manner. Exogenous IL-4 delivery recapitulated tissue AAMϕ expansions, sustained eosinophilia and mediated immunological resistance in Mϕ-intact SCID mice. Co-culturing Brugia with filarial AAMϕ and/or filarial-recruited eosinophils confirmed eosinophils as the larvicidal cell type. Our data demonstrates that IL-4/IL-4Rα activated AAMϕ orchestrate eosinophil immunity to filarial tissue helminth infection.


Assuntos
Brugia Malayi/patogenicidade , Eosinofilia/imunologia , Filariose/imunologia , Interleucina-4/farmacologia , Macrófagos/imunologia , Receptores CCR3/metabolismo , Animais , Antineoplásicos/farmacologia , Brugia Malayi/efeitos dos fármacos , Citocinas/genética , Citocinas/metabolismo , Eosinofilia/tratamento farmacológico , Eosinofilia/parasitologia , Feminino , Filariose/tratamento farmacológico , Filariose/parasitologia , Macrófagos/efeitos dos fármacos , Macrófagos/parasitologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos SCID , Receptores CCR3/genética
16.
Proc Natl Acad Sci U S A ; 114(45): E9712-E9721, 2017 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-29078351

RESUMO

Elimination of filariasis requires a macrofilaricide treatment that can be delivered within a 7-day period. Here we have identified a synergy between the anthelmintic albendazole (ABZ) and drugs depleting the filarial endosymbiont Wolbachia, a proven macrofilaricide target, which reduces treatment from several weeks to 7 days in preclinical models. ABZ had negligible effects on Wolbachia but synergized with minocycline or rifampicin (RIF) to deplete symbionts, block embryogenesis, and stop microfilariae production. Greater than 99% Wolbachia depletion following 7-day combination of RIF+ABZ also led to accelerated macrofilaricidal activity. Thus, we provide preclinical proof-of-concept of treatment shortening using antibiotic+ABZ combinations to deliver anti-Wolbachia sterilizing and macrofilaricidal effects. Our data are of immediate public health importance as RIF+ABZ are registered drugs and thus immediately implementable to deliver a 1-wk macrofilaricide. They also suggest that novel, more potent anti-Wolbachia drugs under development may be capable of delivering further treatment shortening, to days rather than weeks, if combined with benzimidazoles.


Assuntos
Albendazol/farmacologia , Antibacterianos/farmacologia , Filariose/tratamento farmacológico , Wolbachia/efeitos dos fármacos , Animais , Benzimidazóis/farmacologia , Brugia Malayi/microbiologia , Sinergismo Farmacológico , Feminino , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Minociclina/farmacologia , Rifampina/farmacologia
17.
Sci Adv ; 3(9): eaao1551, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28959730

RESUMO

Lymphatic filariasis and onchocerciasis are two important neglected tropical diseases (NTDs) that cause severe disability. Control efforts are hindered by the lack of a safe macrofilaricidal drug. Targeting the Wolbachia bacterial endosymbionts in these parasites with doxycycline leads to a macrofilaricidal outcome, but protracted treatment regimens and contraindications restrict its widespread implementation. The Anti-Wolbachia consortium aims to develop improved anti-Wolbachia drugs to overcome these barriers. We describe the first screening of a large, diverse compound library against Wolbachia. This whole-organism screen, streamlined to reduce bottlenecks, produced a hit rate of 0.5%. Chemoinformatic analysis of the top 50 hits led to the identification of six structurally diverse chemotypes, the disclosure of which could offer interesting avenues of investigation to other researchers active in this field. An example of hit-to-lead optimization is described to further demonstrate the potential of developing these high-quality hit series as safe, efficacious, and selective anti-Wolbachia macrofilaricides.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Avaliação Pré-Clínica de Medicamentos/métodos , Bibliotecas de Moléculas Pequenas , Wolbachia/efeitos dos fármacos , Análise por Conglomerados , Biologia Computacional/métodos , Descoberta de Drogas/métodos , Humanos , Reprodutibilidade dos Testes , Fluxo de Trabalho
18.
PLoS Negl Trop Dis ; 11(5): e0005592, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28481947

RESUMO

Brugia malayi causes the human tropical disease, lymphatic filariasis. Microfilariae (Mf) of this nematode live in the bloodstream and are ingested by a feeding mosquito vector. Interestingly, in a remarkable co-evolutionary adaptation, Mf appearance in the peripheral blood follows a circadian periodicity and reaches a peak when the mosquito is most likely to feed. For the remaining hours, the majority of Mf sequester in the lung capillaries. This circadian phenomenon has been widely reported and is likely to maximise parasite fitness and optimise transmission potential. However, the mechanism of Mf sequestration in the lungs remains largely unresolved. In this study, we demonstrate that B. malayi Mf can, directly adhere to vascular endothelial cells under static conditions and under flow conditions, they can bind at high (but not low) flow rates. High flow rates are more likely to be experienced diurnally. Furthermore, a non-periodic nematode adheres less efficiently to endothelial cells. Strikingly C3, the central component of complement, plays a crucial role in the adherence interaction. These novel results show that microfilariae have the ability to bind to endothelial cells, which may explain their sequestration in the lungs, and this binding is increased in the presence of inflammatory mediators.


Assuntos
Brugia Malayi/fisiologia , Adesão Celular , Complemento C3/metabolismo , Células Endoteliais/parasitologia , Interações Hospedeiro-Patógeno , Animais , Células Endoteliais da Veia Umbilical Humana , Humanos
19.
Sci Rep ; 7(1): 210, 2017 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-28303006

RESUMO

Lymphatic filariasis (LF) and onchocerciasis are priority neglected tropical diseases targeted for elimination. The only safe drug treatment with substantial curative activity against the filarial nematodes responsible for LF (Brugia malayi, Wuchereria bancrofti) or onchocerciasis (Onchocerca volvulus) is doxycycline. The target of doxycycline is the essential endosymbiont, Wolbachia. Four to six weeks doxycycline therapy achieves >90% depletion of Wolbachia in worm tissues leading to blockade of embryogenesis, adult sterility and premature death 18-24 months post-treatment. Long treatment length and contraindications in children and pregnancy are obstacles to implementing doxycycline as a public health strategy. Here we determine, via preclinical infection models of Brugia malayi or Onchocerca ochengi that elevated exposures of orally-administered rifampicin can lead to Wolbachia depletions from filariae more rapidly than those achieved by doxycycline. Dose escalation of rifampicin achieves >90% Wolbachia depletion in time periods of 7 days in B. malayi and 14 days in O. ochengi. Using pharmacokinetic-pharmacodynamic modelling and mouse-human bridging analysis, we conclude that clinically relevant dose elevations of rifampicin, which have recently been determined as safe in humans, could be administered as short courses to filariasis target populations with potential to reduce anti-Wolbachia curative therapy times to between one and two weeks.


Assuntos
Antibacterianos/administração & dosagem , Filariose Linfática/tratamento farmacológico , Filarioidea/microbiologia , Oncocercose/tratamento farmacológico , Rifampina/administração & dosagem , Wolbachia/efeitos dos fármacos , Administração Oral , Animais , Antibacterianos/farmacologia , Brugia Malayi/efeitos dos fármacos , Brugia Malayi/microbiologia , Brugia Malayi/fisiologia , DNA Bacteriano/efeitos dos fármacos , Modelos Animais de Doenças , Filariose Linfática/parasitologia , Desenvolvimento Embrionário/efeitos dos fármacos , Filarioidea/efeitos dos fármacos , Filarioidea/fisiologia , Humanos , Camundongos , Onchocerca volvulus/efeitos dos fármacos , Onchocerca volvulus/microbiologia , Onchocerca volvulus/fisiologia , Oncocercose/parasitologia , Rifampina/farmacologia , Resultado do Tratamento , Wolbachia/genética , Wuchereria bancrofti/efeitos dos fármacos , Wuchereria bancrofti/microbiologia , Wuchereria bancrofti/fisiologia
20.
Gates Open Res ; 1: 7, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29377042

RESUMO

Background: Molecular xenomonitoring (MX), the testing of insect vectors for the presence of human pathogens, has the potential to provide a non-invasive and cost-effective method for monitoring the prevalence of disease within a community. Current MX methods require the capture and processing of large numbers of mosquitoes, particularly in areas of low endemicity, increasing the time, cost and labour required. Screening the excreta/feces (E/F) released from mosquitoes, rather than whole carcasses, improves the throughput by removing the need to discriminate vector species since non-vectors release ingested pathogens in E/F. It also enables larger numbers of mosquitoes to be processed per pool. However, this new screening approach requires a method of efficiently collecting E/F. Methods: We developed a cone with a superhydrophobic surface to allow for the efficient collection of E/F. Using mosquitoes exposed to either Plasmodium falciparum, Brugia malayi or Trypanosoma brucei brucei, we tested the performance of the superhydrophobic cone alongside two other collection methods. Results: All collection methods enabled the detection of DNA from the three parasites. Using the superhydrophobic cone to deposit E/F into a small tube provided the highest number of positive samples (16 out of 18) and facilitated detection of parasite DNA in E/F from individual mosquitoes. Further tests showed that following a simple washing step, the cone can be reused multiple times, further improving its cost-effectiveness. Conclusions: Incorporating the superhydrophobic cone into mosquito traps or holding containers could provide a simple and efficient method for collecting E/F. Where this is not possible, swabbing the container or using the washing method facilitates the detection of the three parasites used in this study.

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