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1.
Clin Pharmacol Ther ; 115(5): 1152-1161, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38294091

RESUMO

For some patients with psoriasis, orally administered small molecule inhibitors of interleukin (IL)-17A may represent a convenient alternative to IL-17A-targeting monoclonal antibodies. This first-in-human study assessed the safety, tolerability, pharmacokinetics (PKs), and peripherally circulating IL-17A target engagement profile of single or multiple oral doses of the small molecule IL-17A inhibitor LY3509754 (NCT04586920). Healthy participants were randomly assigned to receive LY3509754 or placebo in sequential escalating single ascending dose (SAD; dose range 10-2,000 mg) or multiple ascending dose (MAD; dose range 100-1,000 mg daily for 14 days) cohorts. The study enrolled 91 participants (SAD, N = 51 and MAD, N = 40) aged 21-65 years (71% men). LY3509754 had a time to maximum concentration (Tmax) of 1.5-3.5 hours, terminal half-life of 11.4-19.1 hours, and exhibited dose-dependent increases in exposure. LY3509754 had strong target engagement, indicated by elevated plasma IL-17A levels within 12 hours of dosing. Four participants from the 400-mg (n = 1) and 1,000-mg (n = 3) MAD cohorts experienced increased liver transaminases or acute hepatitis (onset ≥ 12 days post-last LY3509754 dose), consistent with drug-induced liver injury (DILI). One case of acute hepatitis was severe, resulted in temporary hospitalization, and was classified as a serious adverse event. No adverse effects on other major organ systems were observed. Liver biopsies from three of the four participants revealed lymphocyte-rich, moderate-to-severe lobular inflammation. We theorize that the DILI relates to an off-target effect rather than IL-17A inhibition. In conclusion, despite strong target engagement and a PK profile that supported once-daily administration, this study showed that oral dosing with LY3509754 was poorly tolerated.


Assuntos
Hepatite , Psoríase , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Administração Oral , Relação Dose-Resposta a Droga , Voluntários Saudáveis , Interleucina-17 , Psoríase/tratamento farmacológico
2.
J Air Waste Manag Assoc ; 73(3): 178-199, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36251984

RESUMO

The Ozone Water-Land Environmental Transition Study, 2018 (OWLETS-2) measured total non-methane hydrocarbons (TNMHC) and EPA PAMS Volatile Organic Compounds (VOCs) on an island site in the northern Chesapeake Bay 2.1 and 3.4 times greater in concentration, respectively, than simultaneous measurements at a land site just 13 km away across the land-water interface. Many PAMS VOCs had larger concentrations at the island site despite lower NEI emissions over the water, but most of the difference comprised species generally consistent with gasoline vapor or exhaust. Sharp chemical differences were observed between the island and mainland and the immediate air ~300 m above the water surface observed by airplane. Ozone formation potential over land was driven by propene and isoprene but toluene and hexane were dominant over the water with little isoprene observed. VOC concentrations over the water were noted to increase diurnally with an inverse pattern to land resulting in increasing NOx sensitivity over the water. Total reactive nitrogen was lower over the water than the nearby land site, but reservoir compounds (NOz) were greater. Ozone production rates were generally slow (~5 ppb hr-1) both at the surface and aloft over the water, even during periods of high ozone (>70 ppbv) at the water surface. However, specific events showed rapid ozone production >40 ppb hr-1 at the water's surface during situations with high VOCs and sufficient NOx. VOC and photochemistry patterns at the island site were driven by marine sources south of the island, implicating marine traffic, and indicate ozone abatement strategies over land may not be similarly applicable to ozone over the water.Implications: Measured chemical properties and patterns driven primarily by marine traffic sources over water during ozone conducive conditions were starkly different to immediately adjacent land sites, implying ozone abatement strategies over land may not be similarly applicable to ozone over the water.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Ozônio , Compostos Orgânicos Voláteis , Ozônio/análise , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Compostos Orgânicos Voláteis/análise , Água , Baías , Emissões de Veículos/análise , Monitoramento Ambiental/métodos , China
3.
BMJ Glob Health ; 7(Suppl 5)2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35798443

RESUMO

Non-communicable disease (NCD) prevention and care in humanitarian contexts has been a long-neglected issue. Healthcare systems in humanitarian settings have focused heavily on communicable diseases and immediate life-saving health needs. NCDs are a significant cause of morbidity and mortality in refugee settings, however, in many situations NCD care is not well integrated into primary healthcare services. Increased risk of poorer outcomes from COVID-19 for people living with NCDs has heightened the urgency of responding to NCDs and shone a spotlight on their relative neglect in these settings. Partnering with the United Nations Refugee Agency (UNHCR) since 2014, Primary Care International has provided clinical guidance and Training of Trainer (ToT) courses on NCDs to 649 health professionals working in primary care in refugee settings in 13 countries. Approximately 2300 healthcare workers (HCW) have been reached through cascade trainings over the last 6 years. Our experience has shown that, despite fragile health services, high staff turnover and competing clinical priorities, it is possible to improve NCD knowledge, skills and practice. ToT programmes are a feasible and practical format to deliver NCD training to mixed groups of HCW (doctors, nurses, technical officers, pharmacy technicians and community health workers). Clinical guidance must be adapted to local settings while co-creating an enabling environment for health workers is essential to deliver accessible, high-quality continuity of care for NCDs. On-going support for non-clinical systems change is equally critical for sustained impact. A shared responsibility for cascade training-and commitment from local health partners-is necessary to raise NCD awareness, influence local and national policy and to meet the UNHCR's objective of facilitating access to integrated prevention and control of NCDs.


Assuntos
COVID-19 , Doenças não Transmissíveis , Refugiados , Agentes Comunitários de Saúde , Mão de Obra em Saúde , Humanos , Doenças não Transmissíveis/prevenção & controle , Atenção Primária à Saúde , Nações Unidas
5.
NAR Genom Bioinform ; 4(1): lqab127, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35047817

RESUMO

In recent years, interest in RNA secondary structure has exploded due to its implications in almost all biological functions and its newly appreciated capacity as a therapeutic agent/target. This surge of interest has driven the development and adaptation of many computational and biochemical methods to discover novel, functional structures across the genome/transcriptome. To further enhance efforts to study RNA secondary structure, we have integrated the functional secondary structure prediction tool ScanFold, into IGV. This allows users to directly perform structure predictions and visualize results-in conjunction with probing data and other annotations-in one program. We illustrate the utility of this new tool by mapping the secondary structural landscape of the human MYC precursor mRNA. We leverage the power of vast 'omics' resources by comparing individually predicted structures with published data including: biochemical structure probing, RNA binding proteins, microRNA binding sites, RNA modifications, single nucleotide polymorphisms, and others that allow functional inferences to be made and aid in the discovery of potential drug targets. This new tool offers the RNA community an easy to use tool to find, analyze, and characterize RNA secondary structures in the context of all available data, in order to find those worthy of further analyses.

6.
BMC Cardiovasc Disord ; 21(1): 486, 2021 10 09.
Artigo em Inglês | MEDLINE | ID: mdl-34627153

RESUMO

INTRODUCTION: Multi-parameter diagnostic devices can simplify cardiometabolic disease diagnosis. However, existing devices may not be suitable for use in low-resource settings, where the burden of non-communicable diseases is high. Here we describe the development of a target product profile (TPP) for a point-of-care multi-parameter device for detection of biomarkers for cardiovascular disease and metabolic disorders, including diabetes, in primary care settings in low- and middle-income countries (LMICs). METHODS: A draft TPP developed by an expert group was reviewed through an online survey and semi-structured expert interviews to identify device characteristics requiring refinement. The draft TPP included 41 characteristics with minimal and optimal requirements; characteristics with an agreement level for either requirement of ≤ 85% in either the survey or among interviewees were further discussed by the expert group and amended as appropriate. RESULTS: Twenty people responded to the online survey and 18 experts participated in the interviews. Twenty-two characteristics had an agreement level of ≤ 85% in either the online survey or interviews. The final TPP defines the device as intended to be used for basic diagnosis and management of cardiometabolic disorders (lipids, glucose, HbA1c, and creatinine) as minimal requirement, and offering an expanded test menu for wider cardiometabolic disease management as optimal requirement. To be suitable, the device should be intended for level 1 healthcare settings or lower, used by minimally trained healthcare workers and allow testing using self-contained cartridges or strips without the need for additional reagents. Throughput should be one sample at a time in a single or multi-analyte cartridge, or optimally enable testing of several samples and analytes in parallel with random access. CONCLUSION: This TPP will inform developers of cardiometabolic multi-parameter devices for LMIC settings, and will support decision makers in the evaluation of existing and future devices.


Assuntos
Análise Química do Sangue/instrumentação , Doenças Cardiovasculares/diagnóstico , Diabetes Mellitus/diagnóstico , Síndrome Metabólica/diagnóstico , Sistemas Automatizados de Assistência Junto ao Leito , Testes Imediatos , Atenção Primária à Saúde , Fitas Reagentes , Biomarcadores/sangue , Glicemia/análise , Doenças Cardiovasculares/sangue , Consenso , Creatinina/sangue , Técnica Delphi , Diabetes Mellitus/sangue , Desenho de Equipamento , Hemoglobinas Glicadas/análise , Humanos , Lipídeos/sangue , Teste de Materiais , Síndrome Metabólica/sangue , Valor Preditivo dos Testes
7.
Lancet Oncol ; 21(5): e280-e291, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32359503

RESUMO

Protracted conflicts in the Middle East have led to successive waves of refugees crossing borders. Chronic, non-communicable diseases are now recognised as diseases that need to be addressed in such crises. Cancer, in particular, with its costly, multidisciplinary care, poses considerable financial and ethical challenges for policy makers. In 2014 and with funding from the United Nations High Commissioner for Refugees, we reported on cancer cases among Iraqi refugees in Jordan (2010-12) and Syria (2009-11). In this Policy Review, we provide data on 733 refugees referred to the United Nations High Commissioner for Refugees in Lebanon (2015-17) and Jordan (2016-17), analysed by cancer type, demographic risk factors, treatment coverage status, and cost. Results show the need for increased funding and evidence-based standard operating procedures across countries to ensure that patients have equitable access to care. We recommend a holistic response to humanitarian crises that includes education, screening, treatment, and palliative care for refugees and nationals and prioritises breast cancer and childhood cancers.


Assuntos
Atenção à Saúde/organização & administração , Política de Saúde , Oncologia/organização & administração , Neoplasias/terapia , Refugiados , Socorro em Desastres/organização & administração , Adolescente , Adulto , Atenção à Saúde/economia , Atenção à Saúde/legislação & jurisprudência , Feminino , Custos de Cuidados de Saúde , Política de Saúde/economia , Política de Saúde/legislação & jurisprudência , Humanos , Jordânia/epidemiologia , Líbano/epidemiologia , Masculino , Oncologia/economia , Oncologia/legislação & jurisprudência , Pessoa de Meia-Idade , Neoplasias/diagnóstico , Neoplasias/economia , Neoplasias/etnologia , Formulação de Políticas , Refugiados/legislação & jurisprudência , Socorro em Desastres/economia , Socorro em Desastres/legislação & jurisprudência , Síria/etnologia , Adulto Jovem
8.
PLoS One ; 13(1): e0190850, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29329326

RESUMO

To date, IL-17A antibodies remain the only therapeutic approach to correct the abnormal activation of the IL-17A/IL-17R signaling complex. Why is it that despite the remarkable success of IL-17 antibodies, there is no small molecule antagonist of IL-17A in the clinic? Here we offer a unique approach to address this question. In order to understand the interaction of IL-17A with its receptor, we combined peptide discovery using phage display with HDX, crystallography, and functional assays to map and characterize hot regions that contribute to most of the energetics of the IL-17A/IL-17R interaction. These functional maps are proposed to serve as a guide to aid in the development of small molecules that bind to IL-17A and block its interaction with IL-17RA.


Assuntos
Colífagos/metabolismo , Interleucina-17/metabolismo , Peptídeos/metabolismo , Receptores de Interleucina-17/metabolismo , Cristalografia por Raios X , Ensaio de Imunoadsorção Enzimática , Células HT29 , Humanos , Interleucina-17/química , Modelos Moleculares , Receptores de Interleucina-17/química , Ressonância de Plasmônio de Superfície
9.
J Air Waste Manag Assoc ; 67(3): 279-291, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27650304

RESUMO

On hot summer days in the eastern United States, electricity demand rises, mainly because of increased use of air conditioning. Power plants must provide this additional energy, emitting additional pollutants when meteorological conditions are primed for poor air quality. To evaluate the impact of summertime NOx emissions from coal-fired electricity generating units (EGUs) on surface ozone formation, we performed a series of sensitivity modeling forecast scenarios utilizing EPA 2018 version 6.0 emissions (2011 base year) and CMAQ v5.0.2. Coal-fired EGU NOx emissions were adjusted to match the lowest NOx rates observed during the ozone seasons (April 1-October 31) of 2005-2012 (Scenario A), where ozone decreased by 3-4 ppb in affected areas. When compared to the highest emissions rates during the same time period (Scenario B), ozone increased ∼4-7 ppb. NOx emission rates adjusted to match the observed rates from 2011 (Scenario C) increased ozone by ∼4-5 ppb. Finally in Scenario D, the impact of additional NOx reductions was determined by assuming installation of selective catalytic reduction (SCR) controls on all units lacking postcombustion controls; this decreased ozone by an additional 2-4 ppb relative to Scenario A. Following the announcement of a stricter 8-hour ozone standard, this analysis outlines a strategy that would help bring coastal areas in the mid-Atlantic region closer to attainment, and would also provide profound benefits for upwind states where most of the regional EGU NOx originates, even if additional capital investments are not made (Scenario A). IMPLICATIONS: With the 8-hr maximum ozone National Ambient Air Quality Standard (NAAQS) decreasing from 75 to 70 ppb, modeling results indicate that use of postcombustion controls on coal-fired power plants in 2018 could help keep regions in attainment. By operating already existing nitrogen oxide (NOx) removal devices to their full potential, ozone could be significantly curtailed, achieving ozone reductions by up to 5 ppb in areas around the source of emission and immediately downwind. Ozone improvements are also significant (1-2 ppb) for areas affected by cross-state transport, especially Mid-Atlantic coast regions that had struggled to meet the 75 ppb standard.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/prevenção & controle , Carvão Mineral , Óxidos de Nitrogênio/análise , Oxidantes Fotoquímicos/análise , Ozônio/análise , Centrais Elétricas , Poluição do Ar/estatística & dados numéricos , Eletricidade , Estados Unidos
10.
Confl Health ; 10: 21, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27777613

RESUMO

BACKGROUND: Given the large burden of non-communicable diseases (NCDs) among both Syrian refugees and the host communities within which they are settled, humanitarian actors and the government of Lebanon face immense challenges in addressing health needs. This study assessed health status, unmet needs, and utilization of health services among Syrian refugees and host communities in Lebanon. METHODS: A cross-sectional survey of Syrian refugees and host communities in Lebanon was conducted using a two-stage cluster survey design with probability proportional to size sampling. To obtain information on chronic NCDs, respondents were asked a series of questions about hypertension, cardiovascular disease, diabetes, chronic respiratory disease, and arthritis. Differences in household characteristics by care-seeking for these conditions were examined using chi-square, t-test, and adjusted logistic regression methods. RESULTS: Over half (50.4 %) of refugee and host community households (60.2 %) reported a member with one of the five NCDs. Host community prevalence rates were significantly higher than refugees for all conditions except chronic respiratory diseases (p = 0.08). Care-seeking for NCDs among refugees and host community households was high across all conditions with 82.9 and 97.8 %, respectively, having sought care in Lebanon for their condition. Refugees utilized primary health care centers (PHCC) (57.7 %) most often while host communities sought care most in private clinics (62.4 %). Overall, 69.7 % of refugees and 82.7 % of host community members reported an out-of-pocket consultation payment (p = 0.041) with an average payment of US$15 among refugees and US$42 for the host community (p <0.001). CONCLUSIONS: Given the protracted nature of the Syrian crisis and the burden on the Lebanese health system, implications for both individuals with NCDs and Lebanon's health system are immense. The burden of out of pocket expenses on persons with NCDs are also substantial, especially given the tenuous economic status of many refugees and the less affluent segments of the Lebanese population. Greater investment in the public sector health system could benefit all parties. Efforts to improve quality of care for NCDs at the primary care level are also a critical component of preventing adverse outcomes and lowering the overall cost of care for NCDs.

11.
Curr Protoc Microbiol ; 42: A.3D.1-A.3D.7, 2016 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-27517337

RESUMO

This protocol describes an efficient method for screening intact bacteria for the presence of desired DNA sequences using the polymerase chain reaction (PCR). This method is commonly referred to as colony PCR. © 2016 by John Wiley & Sons, Inc.


Assuntos
Bactérias/genética , Reação em Cadeia da Polimerase/métodos , Bactérias/classificação , Bactérias/isolamento & purificação , DNA Bacteriano/genética
13.
Brain Topogr ; 29(1): 182-92, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26264375

RESUMO

Ictal MEG recordings constitute rare data. The objective of this study was to evaluate ictal magnetic source localization (MSI), using two algorithms: linearly constrained minimum variance (LCMV), a beamforming technique and equivalent current dipole (ECD). Ictal MSI was studied in six patients. Three of them were undergoing post-operative re-evaluation. For all patients, results were validated by the stereoelectroencephalographic (SEEG) definition of the epileptogenic zone (EZ). EZ was quantified using the epileptogenicity index (EI) method, which accounts for both the propensity of a brain area to generate rapid discharges and the time for this area to become involved in the seizure. EI values range from 0 (no epileptogenicity) to 1 (maximal epileptogenicity). Levels of concordance between ictal MSI and EZ were determined as follows: A: ictal MSI localized the site whose value EI = 1, B: MSI localized a part of the EZ (not corresponding to the maximal value of EI = 1), C: a region could be identified on ictal MSI but not on SEEG, D: a region could be identified on SEEG but not on MSI, E: different regions were localized on MSI and SEEG. Ictal MEG pattern consisted of rhythmic activities between 10 and 20 Hz for all patients. For LCMV (first maxima), levels of concordance were A (two cases), B (two cases) and E (two cases). For ECD fitted on each time point separately (location characterized by the best goodness-of-fit value), levels of concordance were A (one case), B (one case), D (three cases) and E (one case). For ECD calculated for the whole time window, levels of concordance were A (two cases) and D (four cases). Source localization methods performed on rhythmic patterns can localize the EZ as validated by SEEG. In terms of concordance, LCMV was superior to ECD. In some cases, LCMV allows extraction of several maxima that could reflect ictal dynamics. In a medial temporal lobe epilepsy case, ictal MSI indicated an area of delayed propagation and was non-contributory to the presurgical assessment.


Assuntos
Mapeamento Encefálico , Encéfalo/patologia , Encéfalo/fisiopatologia , Epilepsia/patologia , Adolescente , Adulto , Algoritmos , Ondas Encefálicas/fisiologia , Criança , Eletroencefalografia , Feminino , Humanos , Imageamento por Ressonância Magnética , Magnetoencefalografia , Masculino , Processamento de Sinais Assistido por Computador , Adulto Jovem
14.
J Sep Sci ; 38(16): 2813-8, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26047465

RESUMO

Pheophytins and pyropheophytin are degradation products of chlorophyll pigments, and their ratios can be used as a sensitive indicator of stress during the manufacturing and storage of olive oil. They increase over time depending on the storage condition and if the oil is exposed to heat treatments during the refining process. The traditional analysis method includes solvent- and time-consuming steps of solid-phase extraction followed by analysis by high-performance liquid chromatography with ultraviolet detection. We developed an improved dilute/fluorescence method where multi-step sample preparation was replaced by a simple isopropanol dilution before the high-performance liquid chromatography injection. A quaternary solvent gradient method was used to include a fourth strong solvent wash on a quaternary gradient pump, which avoided the need to premix any solvents and greatly reduced the oil residues on the column from previous analysis. This new method not only reduces analysis cost and time but shows reliability, repeatability, and improved sensitivity, especially important for low-level samples.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Azeite de Oliva/análise , Feofitinas/análise , Clorofila/química , Cromatografia Líquida de Alta Pressão/instrumentação , Armazenamento de Alimentos , Reprodutibilidade dos Testes
15.
J AOAC Int ; 98(2): 390-6, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25905745

RESUMO

An HPLC method for simultaneous determination of vitamins A and D3 in fluid milk was developed and validated. Saponification and extraction conditions were studied for optimum recovery and simplicity. An RP HPLC system equipped with a C18 column and diode array detector was used for quantitation. The method was subjected to a single-laboratory validation using skim, 2% fat, and whole milk samples at concentrations of 50, 100, and 200% of the recommended fortification levels for vitamins A and D3 for Grade "A" fluid milk. The method quantitation limits for vitamins A and D3 were 0.0072 and 0.0026 µg/mL, respectively. Average recoveries between 94 and 110% and SD values ranging from 2.7 to 6.9% were obtained for both vitamins A and D3. The accuracy of the method was evaluated using a National Institute of Standards and Technology standard reference material (1849a) and proficiency test samples.


Assuntos
Colecalciferol/química , Cromatografia Líquida/métodos , Leite/química , Vitamina A/química , Animais , Bovinos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Incerteza
16.
PLoS One ; 7(12): e52276, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23251706

RESUMO

Burkholderia pseudomallei is the causative agent of melioidosis and is a major mediator of sepsis in its endemic areas. Because of the low LD(50) via aerosols and resistance to multiple antibiotics, it is considered a Tier 1 select agent by the CDC and APHIS. B. pseudomallei is an encapsulated bacterium that can infect, multiply, and persist within a variety of host cell types. In vivo studies suggest that macrophages and neutrophils are important for controlling B. pseudomallei infections, however few details are known regarding how neutrophils respond to these bacteria. Our goal is to describe the capacity of human neutrophils to control highly virulent B. pseudomallei compared to the relatively avirulent, acapsular B. thailandensis using in vitro analyses. B. thailandensis was more readily phagocytosed than B. pseudomallei, but both displayed similar rates of persistence within neutrophils, indicating they possess similar inherent abilities to escape neutrophil clearance. Serum opsonization studies showed that both were resistant to direct killing by complement, although B. thailandensis acquired significantly more C3 on its surface than B. pseudomallei, whose polysaccharide capsule significantly decreased the levels of complement deposition on the bacterial surface. Both Burkholderia species showed significantly enhanced uptake and killing by neutrophils after critical levels of C3 were deposited. Serum-opsonized Burkholderia induced a significant respiratory burst by neutrophils compared to unopsonized bacteria, and neutrophil killing was prevented by inhibiting NADPH-oxidase. In summary, neutrophils can efficiently kill B. pseudomallei and B. thailandensis that possess a critical threshold of complement deposition, and the relative differences in their ability to resist surface opsonization may contribute to the distinct virulence phenotypes observed in vivo.


Assuntos
Cápsulas Bacterianas/metabolismo , Burkholderia pseudomallei/metabolismo , Complemento C3/metabolismo , NADPH Oxidases/metabolismo , Neutrófilos/metabolismo , Polissacarídeos Bacterianos/metabolismo , Cápsulas Bacterianas/imunologia , Burkholderia pseudomallei/imunologia , Complemento C3/imunologia , Humanos , Melioidose/imunologia , Melioidose/metabolismo , Melioidose/microbiologia , NADPH Oxidases/imunologia , Neutrófilos/imunologia , Neutrófilos/microbiologia , Fagocitose/imunologia , Polissacarídeos Bacterianos/imunologia , Explosão Respiratória/imunologia , Virulência/imunologia
17.
FEMS Immunol Med Microbiol ; 65(1): 78-83, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22340259

RESUMO

Platelets are known contributors of hemostasis but have recently been shown to be important in inflammation and infectious diseases. Moreover, thrombocytopenia is often observed in patients with sepsis. We previously reported that platelets actively phagocytosed IgG-coated latex beads. In this study, the capacity of human platelets to participate in host defense against bacterial infections was determined by assessing their ability to kill Escherichia coli. Washed human platelets were incubated with unopsonized or IgG-opsonized E. coli and evaluated for binding and killing of E. coli. We found that although both unopsonized and IgG-opsonized E. coli were associated with platelets, only IgG-opsonized E. coli were efficiently killed unless platelets were activated by a potent agonist. The bactericidal activity was dependent on FcγRIIA, was sensitive to cytochalasin D, but was not due to reactive oxygen metabolites. These data suggest that platelets may play an important role in protection against infection.


Assuntos
Anticorpos Antibacterianos/imunologia , Plaquetas/imunologia , Escherichia coli/imunologia , Imunoglobulina G/imunologia , Viabilidade Microbiana , Proteínas Opsonizantes/imunologia , Aderência Bacteriana , Citocalasina D/metabolismo , Humanos , Espécies Reativas de Oxigênio/toxicidade , Receptores de IgG/metabolismo
18.
J Comput Neurosci ; 31(2): 401-18, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21344300

RESUMO

Gamma oscillations can synchronize with near zero phase lag over multiple cortical regions and between hemispheres, and between two distal sites in hippocampal slices. How synchronization can take place over long distances in a stable manner is considered an open question. The phase resetting curve (PRC) keeps track of how much an input advances or delays the next spike, depending upon where in the cycle it is received. We use PRCs under the assumption of pulsatile coupling to derive existence and stability criteria for 1:1 phase-locking that arises via bidirectional pulse coupling of two limit cycle oscillators with a conduction delay of any duration for any 1:1 firing pattern. The coupling can be strong as long as the effect of one input dissipates before the next input is received. We show the form that the generic synchronous and anti-phase solutions take in a system of two identical, identically pulse-coupled oscillators with identical delays. The stability criterion has a simple form that depends only on the slopes of the PRCs at the phases at which inputs are received and on the number of cycles required to complete the delayed feedback loop. The number of cycles required to complete the delayed feedback loop depends upon both the value of the delay and the firing pattern. We successfully tested the predictions of our methods on networks of model neurons. The criteria can easily be extended to include the effect of an input on the cycle after the one in which it is received.


Assuntos
Potenciais de Ação/fisiologia , Relógios Biológicos/fisiologia , Condução Nervosa/fisiologia , Animais , Humanos , Modelos Neurológicos , Rede Nervosa/fisiologia , Vias Neurais/fisiologia , Neurônios/fisiologia , Tempo de Reação/fisiologia
19.
PLoS One ; 5(7): e11445, 2010 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-20625435

RESUMO

B cells are typically characterized as positive regulators of the immune response, primarily by producing antibodies. However, recent studies indicate that various subsets of B cells can perform regulatory functions mainly through IL-10 secretion. Here we discovered that peritoneal B-1 (B-1P) cells produce high levels of IL-10 upon stimulation with several Toll-like receptor (TLR) ligands. High levels of IL-10 suppressed B-1P cell proliferation and differentiation response to all TLR ligands studied in an autocrine manner in vitro and in vivo. IL-10 that accumulated in cultures inhibited B-1P cells at second and subsequent cell divisions mainly at the G1/S interphase. IL-10 inhibits TLR induced B-1P cell activation by blocking the classical NF-kappaB pathway. Co-stimulation with CD40 or BAFF abrogated the IL-10 inhibitory effect on B-1P cells during TLR stimulation. Finally, B-1P cells adoptively transferred from the peritoneal cavity of IL-10(-/-) mice showed better clearance of Borrelia hermsii than wild-type B-1P cells. This study described a novel autoregulatory property of B-1P cells mediated by B-1P cell derived IL-10, which may affect the function of B-1P cells in infection and autoimmunity.


Assuntos
Subpopulações de Linfócitos B/imunologia , Subpopulações de Linfócitos B/metabolismo , Borrelia/imunologia , Interleucina-10/metabolismo , Animais , Fator Ativador de Células B/farmacologia , Subpopulações de Linfócitos B/efeitos dos fármacos , Western Blotting , Borrelia/patogenicidade , Antígenos CD40/farmacologia , Proliferação de Células , Células Cultivadas , Interleucina-10/genética , Interleucina-10/farmacologia , Interleucina-5/farmacologia , Lipopolissacarídeos/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , NF-kappa B/metabolismo , Reação em Cadeia da Polimerase , Transdução de Sinais/efeitos dos fármacos , Receptor 4 Toll-Like/agonistas , Receptor 4 Toll-Like/metabolismo
20.
J Leukoc Biol ; 86(3): 727-36, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19458267

RESUMO

Relapsing fever spirochetes, such as Borrelia hermsii, proliferate to high levels in their hosts' bloodstream until production of IgM against borrelial surface proteins promotes bacterial clearance. The mechanisms by which B. hermsii survives in host blood, as well as the immune mediators that control this infection, remain largely unknown. It has been hypothesized that B. hermsii is naturally resistant to killing by the alternative pathway of complement activation as a result of its ability to bind factor H, a host complement regulator. However, we found that Cfh(-/-) mice were infected to levels identical to those seen in wild-type mice. Moreover, only a small minority of B. hermsii in the blood of wild-type mice had detectable levels of factor H adhered to their outer surfaces. In vitro, complement was found to play a statistically significant role in antibody-mediated inactivation of B. hermsii, although in vivo studies indicated that complement is not essential for host control of B. hermsii. Depletion of mphi and DC from mice had significant impacts on B. hermsii infection, and depleted mice were unable to control bloodstream infections, leading to death. Infection studies using muMT indicated a significant antibody-independent role for mphi and/or DC in host control of relapsing fever infection. Together, these findings indicate mphi and/or DC play a critical role in the production of B. hermsii-specific IgM and for antibody-independent control of spirochete levels.


Assuntos
Borrelia/imunologia , Proteínas do Sistema Complemento/metabolismo , Fagócitos/metabolismo , Febre Recorrente/imunologia , Animais , Anticorpos Antibacterianos/imunologia , Borrelia/genética , Borrelia/metabolismo , Ativação do Complemento/imunologia , Fator H do Complemento/metabolismo , Cruzamentos Genéticos , Imunoglobulina M/biossíntese , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fagócitos/imunologia , Febre Recorrente/genética , Febre Recorrente/microbiologia
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