Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Ann Intern Med ; 176(1): 67-76, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36508736

RESUMO

BACKGROUND: Monkeypox, a viral zoonotic disease, is causing a global outbreak outside of endemic areas. OBJECTIVE: To characterize the outbreak of monkeypox in Montréal, the first large outbreak in North America. DESIGN: Epidemiologic and laboratory surveillance data and a phylogenomic analysis were used to describe and place the outbreak in a global context. SETTING: Montréal, Canada. PATIENTS: Probable or confirmed cases of monkeypox. MEASUREMENTS: Epidemiologic, clinical, and demographic data were aggregated. Whole-genome sequencing and phylogenetic analysis were performed for a set of outbreak sequences. The public health response and its evolution are described. RESULTS: Up to 18 October 2022, a total of 402 cases of monkeypox were reported mostly among men who have sex with men (MSM), most of which were suspected to be acquired through sexual contact. All monkeypox genomes nested within the B.1 lineage. Montréal Public Health worked closely with the affected communities to control the outbreak, becoming the first jurisdiction to offer 1 dose of the Modified Vaccinia Ankara-Bavarian Nordic vaccine as preexposure prophylaxis (PrEP) to those at risk in early June 2022. Two peaks of cases were seen in early June and July (43 and 44 cases per week, respectively) followed by a decline toward near resolution of the outbreak in October. Reasons for the biphasic peak are not fully elucidated but may represent the tempo of vaccination and/or several factors related to transmission dynamics and case ascertainment. LIMITATIONS: Clinical data are self-reported. Limited divergence among sequences limited genomic epidemiologic conclusions. CONCLUSION: A large outbreak of monkeypox occurred in Montréal, primarily among MSM. Successful control of the outbreak rested on early and sustained engagement with the affected communities and rapid offer of PrEP vaccination to at-risk persons. PRIMARY FUNDING SOURCE: None.


Assuntos
Mpox , Minorias Sexuais e de Gênero , Masculino , Humanos , Filogenia , Homossexualidade Masculina , Mpox/epidemiologia , Surtos de Doenças , América do Norte/epidemiologia , Autorrelato
2.
Transpl Infect Dis ; 23(4): e13568, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33450126

RESUMO

BACKGROUND: Invasive aspergillosis (IA) is a rare but highly lethal complication after orthotopic liver transplantation (OLT). Targeted antifungal prophylaxis has been proposed as a strategy to prevent IA among orthotopic liver transplant recipient (OLTr), but limited data are available to support its efficacy. METHOD: We conducted a single-center, retrospective, before and after cohort study, comparing IA incidences among OLTr who did not receive antifungal prophylaxis after transplantation (cohort 1) to OLTr who received targeted antifungal prophylaxis after liver transplantation (cohort 2). Patients in cohort 2 received caspofungin prophylaxis if they presented one of the following risk factors: retransplantation, acute liver failure, dialysis, or Aspergillus colonization prior to transplantation. The primary outcome was IA at 90 days after transplantation. RESULTS: A total of 391 OLTr were included in the study; 181 patients in the cohort 1 (no prophylaxis) and 210 patients in the cohort 2 (targeted prophylaxis). Among patients in cohort 2, 19% (40/ 210) were considered at high risk for IA and 85% (34/40) of those received caspofungin prophylaxis. The incidence of IA at 90 days was 3.3% (6/ 181) and 0.5% (1/ 210), in cohort 1 and 2, respectively (OR 0.14; 95%CI 0.01-0.83; P = .03). Ninety-day mortality was similar among the two cohorts (3.9% (7/181) and 2.4% (5/210) in cohort 1 and 2, respectively (OR 0.61; 95% 0.18-1.93; P = .40)). The 90-day mortality among the OLTs with IA was 71% (5/7). CONCLUSION: Targeted caspofungin prophylaxis was associated with lower rate of IA.


Assuntos
Aspergilose , Transplante de Fígado , Aspergilose/tratamento farmacológico , Aspergilose/epidemiologia , Aspergilose/prevenção & controle , Caspofungina , Estudos de Coortes , Humanos , Transplante de Fígado/efeitos adversos , Estudos Retrospectivos
3.
J Biol Chem ; 293(36): 14122-14133, 2018 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-30030381

RESUMO

Viperin is a radical SAM enzyme that has been shown to possess antiviral activity against a broad spectrum of viruses; however, its molecular mechanism is unknown. We report here that recombinant fungal and archaeal viperin enzymes catalyze the addition of the 5'-deoxyadenosyl radical (5'-dA•) to the double bond of isopentenyl pyrophosphate (IPP), producing a new compound we named adenylated isopentyl pyrophosphate (AIPP). The reaction is specific for IPP, as other pyrophosphate compounds involved in the mevalonate biosynthetic pathway did not react with 5'-dA• Enzymatic reactions employing IPP derivatives as substrates revealed that any chemical change in IPP diminishes its ability to be an effective substrate of fungal viperin. Mutational studies disclosed that the hydroxyl group on the side chain of Tyr-245 in fungal viperin is the likely source of hydrogen in the last step of the radical addition, providing mechanistic insight into the radical reaction catalyzed by fungal viperin. Structure-based molecular dynamics (MD) simulations of viperin interacting with IPP revealed a good fit of the isopentenyl motif of IPP to the active site cavity of viperin, unraveling the molecular basis of substrate specificity of viperin for IPP. Collectively, our findings indicate that IPP is an effective substrate of fungal and archaeal viperin enzymes and provide critical insights into the reaction mechanism.


Assuntos
Hemiterpenos/metabolismo , Compostos Organofosforados/metabolismo , S-Adenosilmetionina/metabolismo , Antivirais , Domínio Catalítico , Fungos/enzimologia , Simulação de Dinâmica Molecular , Ligação Proteica , S-Adenosilmetionina/química , Especificidade por Substrato
4.
Can Commun Dis Rep ; 49(2-3): 76-80, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38090723

RESUMO

Background: Tecovirimat (TCV, TPOXX®) is an orthopox-specific antiviral drug indicated for the treatment of smallpox. There is also a mechanistic basis for its use in mpox infection. However, its approval was based on animal studies, and its efficacy and side-effect profile in human patients with disease is unknown. Methods: During the 2022 international mpox epidemic, clinicians in Canada accessed TCV from the Public Health Agency of Canada's National Emergency Strategic Stockpile for severe cases of mpox disease. We describe the use of TCV in nine adults with severe mpox virus infection in Montréal, Canada. Results: Five patients were treated for severe and potentially life-threatening head and neck symptoms, while four were treated for genitourinary or anorectal disease. Two-thirds of patients were also treated for suspected bacterial superinfection. All patients recovered (median time to resolution of severe symptoms: nine days) without relapse or hospital readmission. No patients reported adverse events attributable to TCV and no patients stopped their treatment early. Conclusion: Our experience suggests that TCV is well tolerated and may accelerate recovery in severe cases. These preliminary, observational data may also be explained by concomitant treatment for superinfection and are limited by the absence of a control group. Controlled, clinical trials should be conducted to clarify the attributable benefit of TCV in severe mpox infection.

5.
Int J Infect Dis ; 136: 136-145, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37717649

RESUMO

BACKGROUND: Vaccination protects against severe COVID-19 manifestations. For those with post-COVID-19 conditions (PCC) or long COVID, the impact of COVID-19 vaccination on the evolution of symptoms, immune responses, and viral persistence is unclear. METHODS: In this prospective observational cohort study, we evaluated the number of PCC symptoms, affected organ systems, and psychological well-being scores before and after patients with PCC received COVID-19 vaccination. We simultaneously evaluated biomarkers of systemic inflammation and levels of plasma cytokines/chemokines. We measured plasma and intracellular levels of SARS-CoV-2 antigens, and immunoreactivity to SARS-CoV-2 antigens in blood. RESULTS: COVID-19 vaccination was associated with decreases in number of PCC symptoms (pre-vaccination: 6.56 ± 3.1 vs post-vaccination: 3.92 ± 4.02; P <0.001) and affected organ systems (pre-vaccination: 3.19 ± 1.04 vs post-vaccination: 1.89 ± 1.12; P <0.001), and increases in World Health Organization (WHO)-5 Well-Being Index Scores (pre-vaccination: 42.67 ± 22.76 vs post-vaccination: 56.15 ± 22.83; P <0.001). Patients with PCC also had significantly decreased levels of several pro-inflammatory plasma cytokines/chemokines after COVID-19 vaccination including sCD40L, GRO-⍺, macrophage inflammatory protein (MIP)-1⍺, interleukin (IL)-12p40, G-colony stimulating factor (CSF), M-CSF, IL-1ß, and stem cell factor (SCF). PCC participants presented a certain level of immunoreactivity toward SARS-CoV-2, that was boosted with vaccination. SARS-CoV-2 S1 antigen persisted in the blood of PCC participants, mostly in non-classical monocytes, regardless of participants receiving vaccination. CONCLUSIONS: Our study shows higher pro-inflammatory responses associated with PCC symptoms and brings forward a possible role for vaccination in mitigating PCC symptoms by decreasing systemic inflammation. We also observed persistence of viral products independent of vaccination that could be involved in perpetuating inflammation through non-classical monocytes.


Assuntos
COVID-19 , Síndrome de COVID-19 Pós-Aguda , Humanos , COVID-19/prevenção & controle , Vacinas contra COVID-19 , Estudos Prospectivos , SARS-CoV-2 , Vacinação , Citocinas , Inflamação , Imunidade , Quimiocinas
6.
Lancet Infect Dis ; 23(2): 196-206, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36216018

RESUMO

BACKGROUND: The early epidemiology of the 2022 monkeypox epidemic in non-endemic countries differs substantially from the epidemiology previously reported from endemic countries. We aimed to describe the epidemiological and clinical characteristics among individuals with confirmed cases of monkeypox infection. METHODS: We descriptively analysed data for patients with confirmed monkeypox who were included in the GeoSentinel global clinical-care-based surveillance system between May 1 and July 1 2022, across 71 clinical sites in 29 countries. Data collected included demographics, travel history including mass gathering attendance, smallpox vaccination history, social history, sexual history, monkeypox exposure history, medical history, clinical presentation, physical examination, testing results, treatment, and outcomes. We did descriptive analyses of epidemiology and subanalyses of patients with and without HIV, patients with CD4 counts of less than 500 cells per mm3 or 500 cells per mm3 and higher, patients with one sexual partner or ten or more sexual partners, and patients with or without a previous smallpox vaccination. FINDINGS: 226 cases were reported at 18 sites in 15 countries. Of 211 men for whom data were available, 208 (99%) were gay, bisexual, or men who have sex with men (MSM) with a median age of 37 years (range 18-68; IQR 32-43). Of 209 patients for whom HIV status was known, 92 (44%) men had HIV infection with a median CD4 count of 713 cells per mm3 (range 36-1659; IQR 500-885). Of 219 patients for whom data were available, 216 (99%) reported sexual or close intimate contact in the 21 days before symptom onset; MSM reported a median of three partners (IQR 1-8). Of 195 patients for whom data were available, 78 (40%) reported close contact with someone who had confirmed monkeypox. Overall, 30 (13%) of 226 patients were admitted to hospital; 16 (53%) of whom had severe illness, defined as hospital admission for clinical care rather than infection control. No deaths were reported. Compared with patients without HIV, patients with HIV were more likely to have diarrhoea (p=0·002), perianal rash or lesions (p=0·03), and a higher rash burden (median rash burden score 9 [IQR 6-21] for patients with HIV vs median rash burden score 6 [IQR 3-14] for patients without HIV; p<0·0001), but no differences were identified in the proportion of men who had severe illness by HIV status. INTERPRETATION: Clinical manifestations of monkeypox infection differed by HIV status. Recommendations should be expanded to include pre-exposure monkeypox vaccination of groups at high risk of infection who plan to engage in sexual or close intimate contact. FUNDING: US Centers for Disease Control and Prevention, International Society of Travel Medicine.


Assuntos
Exantema , Infecções por HIV , Mpox , Minorias Sexuais e de Gênero , Varíola , Masculino , Humanos , Adolescente , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Idoso , Feminino , Infecções por HIV/prevenção & controle , Homossexualidade Masculina , Estudos Transversais , Mpox/epidemiologia
7.
IDCases ; 30: e01628, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36345425

RESUMO

Monkeypox is a zoonotic Orthopoxvirus infection usually present in regions of Africa. Recent outbreaks of Monkeypox infection have been reported in non endemic region and human-to-human contact is believed to be the main driver for propagation. While the disease is usually self-contained, severe complications, such as neurological and ocular involvements may arise. We report the case of a 34-year-old male who presented with myocarditis and concurrent genital Monkeypox infection. Other usual causes of myocardial injury were ruled out. We believe it to be the first documented case of myocarditis secondary to Monkeypox. We report a new complication of the disease and the possible underlying mechanisms. Our case report raises awareness about possible unknown complications of Monkeypox as outbreaks continue to happen around the world.

8.
Blood ; 114(8): 1633-44, 2009 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-19546479

RESUMO

Inflammatory bone loss in septic and inflammatory conditions is due to increased activity of osteoclasts that requires receptor activator of NF-kappa B-ligand (RANKL). Neutrophils are the predominant infiltrating cells in these conditions. Although disease severity is linked to neutrophils, their role in evolution of bony lesions is not clear. We show that lipopolysaccharide (LPS), a toll-like receptor 4 ligand, up-regulated the expression of membrane RANKL in human blood neutrophils and murine air pouch-derived neutrophils. LPS-activated human and murine neutrophils, cocultured with human monocyte-derived osteoclasts and RAW 264.7 cells, respectively, stimulated bone resorption. Transfection of PLB-985 neutrophil-like cells with RANKL antisense RNA reduced osteoclastogenesis. Synovial fluid neutrophils of patients with exacerbation of rheumatoid arthritis strongly expressed RANKL and activated osteoclastogenesis in coculture systems. Osteoprotegerin, the RANKL decoy receptor, suppressed osteoclast activation by neutrophils from these different sources. Moreover, direct cell-cell contact between neutrophils and osteoclasts was visualized by confocal laser microscopy. Activation of neutrophil membrane-bound RANKL was linked to tyrosine phosphorylation of Src-homology domain-containing cytosolic phosphatase 1 with concomitant down-regulation of cytokine production. The demonstration of these novel functions of neutrophils highlights their potential role in osteoimmunology and in therapeutics of inflammatory bone disease.


Assuntos
Reabsorção Óssea/etiologia , Neutrófilos/fisiologia , Ligante RANK/fisiologia , Receptor 4 Toll-Like/fisiologia , Animais , Antígenos de Superfície/metabolismo , Antígenos de Superfície/fisiologia , Reabsorção Óssea/metabolismo , Adesão Celular/efeitos dos fármacos , Adesão Celular/fisiologia , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/fisiologia , Movimento Celular/efeitos dos fármacos , Movimento Celular/fisiologia , Células Cultivadas , Humanos , Ligantes , Lipopolissacarídeos/farmacologia , Camundongos , Neutrófilos/efeitos dos fármacos , Neutrófilos/metabolismo , Osteoclastos/efeitos dos fármacos , Osteoclastos/metabolismo , Osteoclastos/fisiologia , Ligante RANK/antagonistas & inibidores , Ligante RANK/metabolismo , RNA Interferente Pequeno/farmacologia , Receptor 4 Toll-Like/metabolismo , Receptores Toll-Like/metabolismo
9.
Nat Commun ; 12(1): 6381, 2021 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-34737303

RESUMO

Cyclic-oligonucleotide-based antiphage signaling systems (CBASS) are diverse and abundant in bacteria. Here, we present the biochemical and structural characterization of two CBASS systems, composed of CdnG and Cap5, from Asticcacaulis sp. and Lactococcus lactis. We show that CdnG from Asticcacaulis sp. synthesizes 3',2'-cGAMP in vitro, and 3',2'-cGAMP is the biological signaling molecule that activates Cap5 for DNA degradation. Crystal structures of Cap5, together with the SAVED domain in complex with 3',2'-cGAMP, provide insight into the architecture of Cap5 as well as molecular recognition of 3',2'-cGAMP by the SAVED domain of Cap5. Amino acid conservation of the SAVED domain of Cap5, together with mutational studies, led us to propose a mechanism of Back-to-Front stacking of two SAVED domains, mediated by 3',2'-cGAMP, to activate HNH nuclease domain for DNA degradation. This study of the most abundant CBASS system provides insights into the mechanisms employed by bacteria in their conflicts against phage.


Assuntos
Bactérias/metabolismo , Proteínas de Bactérias/metabolismo , Bactérias/genética , Caulobacteraceae/genética , Caulobacteraceae/metabolismo , Lactococcus lactis/genética , Lactococcus lactis/metabolismo , Mutagênese Sítio-Dirigida , Nucleotídeos Cíclicos/metabolismo
10.
IDCases ; 20: e00715, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32140413

RESUMO

Anisakiasis is human zoonotic parasitic infection caused by a nematode parasite called Anisakis. This infection is usually reported in Asian countries where consumption of raw seafood is common. Very few cases have been reported in North America. We present the case of a female Canadian patient with an Anisakis larvae in an incarcerated ventral hernia. Cases of Anisakis infections are exceedingly rare in western countries, with very few previous reports describing extra-gastrointestinal cases. Diagnosis is often difficult since the symptoms of anisakiasis are not pathognomonic. As the larvae cannot survive in the body, conservative treatment might be effective in intestinal anisakiasis and surgery is usually performed when complications are encountered. Preventive measures are crucial and include educating the public about the risks of raw fish consumption and the importance of visually inspecting consumed fish and freezing it before ingestion to kill the larvae and prevent the infection.

11.
Lab Invest ; 89(10): 1084-99, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19636293

RESUMO

Essential cells of innate immunity, neutrophils are often considered to be a homogenous population of terminally differentiated cells. During inflammation, neutrophils are extravasated cells exposed to local factors that prolong their survival and activate their production of mediators implicated in disease progression. In this study, a phenotypically distinct subset of human neutrophils that appear after prolonged exposure to cytokines was characterized. Freshly isolated neutrophils from healthy donors were incubated with granulocyte-macrophage colony-stimulating factor, tumor necrosis factor-alpha and interleukin (IL)-4, three cytokines that are locally present in various inflammatory conditions. Eight to 17% of neutrophils survived beyond 72 h. This subset of non-apoptotic neutrophils, as evaluated by three different markers, was enriched by discontinuous Percoll gradient centrifugation before studying their phenotype. These viable neutrophils showed neoexpression of HLA-DR, CD80 and CD49d. Compared with freshly isolated neutrophils, they responded differentially to second signals similar to formyl-methionyl-leucyl-phenylalanine with three- to four-fold increases in production of superoxide anions and leukotrienes. These cells augmented their phagocytic index by 141%, increased their adhesion to human primary fibroblasts, but reduced their migration in response to chemotactic stimuli and decreased exocytosis of primary and secondary granules. In addition, they produced substantial amounts of IL-8, IL-1Ra and IL-1beta. This neutrophil subset had a unique profile of phosphorylation of intracellular signaling molecules. In conclusion, the present identification of a novel neutrophil phenotype highlights the reprogammable character of the neutrophil. This aspect is crucial for our understanding of its contribution to disease pathogenesis and host defense.


Assuntos
Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Inflamação/metabolismo , Interleucina-4/metabolismo , Neutrófilos/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Biomarcadores/metabolismo , Adesão Celular , Sobrevivência Celular , Quimiotaxia , Exocitose , Fibroblastos/fisiologia , Humanos , Inflamação/imunologia , Proteína Antagonista do Receptor de Interleucina 1/biossíntese , Interleucina-1beta/biossíntese , Interleucina-8/biossíntese , Leucotrienos/biossíntese , Neutrófilos/citologia , Proteínas Opsonizantes , Fagocitose , Fenótipo , Fosforilação , Proteínas Serina-Treonina Quinases/metabolismo , Proteoma , Superóxidos/metabolismo , Zimosan
12.
Open Forum Infect Dis ; 6(4): ofz088, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30949534

RESUMO

Mycobacterium africanum is an important cause of human tuberculosis and is found almost exclusively in West Africa. We identified a cluster of patients in Montreal, Canada, with M africanum disease that share identical genotypic signatures by mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) typing and a putative epidemiological link, thus providing evidence of possible local transmission of M africanum in Montreal over a 10-year period.

13.
Lab Invest ; 88(2): 171-84, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18040268

RESUMO

Osteoprotegerin (OPG) acts as a decoy receptor for receptor activator of nuclear factor-kappaB ligand (RANKL) and TNF-related apoptosis-inducing ligand (TRAIL). OPG regulates bone remodeling and the immune response. The primary objective was to decipher, among human peripheral blood mononuclear leukocytes (PBML) that produce OPG, the subset(s) responsible for this synthesis and its regulation. To this end, normal human PBML and CD4-, 8-, 19-, 14-enriched subpopulations were studied in vitro for OPG synthesis. PBML were subjected to adherence and immunomagnetic separation, and OPG expression was analyzed by PCR, northern and western blotting, and ELISA. The antiapoptotic effects of OPG were studied on TRAIL-stimulated RPMI 8226 myeloma cells. OPG was time-dependently produced by primary CD4+ T lymphocytes exclusively. OPG secretion was upregulated by anti-CD3 antibody stimulation or incubation with interleukin (IL)-4, IL-1beta, TNF-alpha, GM-CSF, and vitamin D(3). In contrast, IL-10 inhibited the basal and IL-4-induced production of OPG by T cells. Conditioned media from activated T lymphocytes decreased TRAIL-induced apoptosis of RPMI 8226 cells. This effect was reversed by addition of RANKL to the T-cell conditioned media. As human immunodeficiency virus-1 (HIV-1) targets CD4+ T cells, we evaluated the effects of recombinant HIV-1 gp120 proteins on OPG synthesis. The gp120 from three different HIV-1 strains significantly reduced the basal output of OPG from T cells. Furthermore, all four protease inhibitors (PIs) used in highly active antiretroviral therapy decreased OPG synthesis by human blood T cells, nelfinavir being the most efficient PI. The simultaneous presence of an HIV-1 gp120 and a PI abrogated the basal output of OPG. In conclusion, these results highlight a new role for T lymphocytes involved in pathologies. Activated CD4+ T cells could, through OPG release, have a paracrine effect on adjacent cells and contribute to reduce the local process of bone remodeling and cellular apoptosis.


Assuntos
Linfócitos T CD4-Positivos/metabolismo , Osteoprotegerina/biossíntese , Anticorpos/farmacologia , Apoptose/efeitos dos fármacos , Complexo CD3/imunologia , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linhagem Celular Tumoral , Colecalciferol/farmacologia , Meios de Cultivo Condicionados/farmacologia , Citocinas/farmacologia , Regulação para Baixo , Proteína gp120 do Envelope de HIV/farmacologia , Inibidores da Protease de HIV/farmacologia , Humanos , Fatores de Tempo , Regulação para Cima
15.
Med Sci (Paris) ; 23(10): 862-7, 2007 Oct.
Artigo em Francês | MEDLINE | ID: mdl-17937896

RESUMO

The neutrophil has long been considered a phagocytic cell with a short life-span whose major role is to destroy intruders to the body. Toll receptors and anti-infectious factors such as defensin, perforin and granzymes are newly discovered mechanisms used by neutrophils for the first line of defense against invaders. Moreover, subpopulations of neutrophils share specific functions like the synthesis of certain cytokines and chemokines, as well as the expression of immunoreceptors like the T cell receptor. A primary consequence of inflammation on neutrophils is a delay in their spontaneous programmed cell death. Hence, this multifunctional cell is also a necessary actor of the acquired immune response. Neutrophils have the capacity to degrade and process antigens as well as efficiently present antigenic peptides to lymphocytes. Neutrophil interactions with immune cells, in particular dendritic cells, lead to the formation of IL-12 and TNF-alpha deviating the immune response towards a Th1 phenotype. Thus, the neutrophil exhibits a cellular plasticity that explains its capacity to transdifferentiate depending on the local requirements of the immune response. The neutrophil is probably the most underappreciated immune cell among hematopoietic leukocytes, and many neutrophil functions remain to be unraveled.


Assuntos
Imunidade Inata , Neutrófilos/imunologia , Animais , Apresentação de Antígeno/imunologia , Apoptose , Diferenciação Celular , Citocinas/farmacologia , Citocinas/fisiologia , Células Dendríticas/imunologia , Humanos , Inflamação/imunologia , Subpopulações de Linfócitos/imunologia , Modelos Imunológicos , Neutrófilos/classificação , Neutrófilos/efeitos dos fármacos , Fagocitose/imunologia , Receptores Imunológicos/imunologia
16.
Indian J Pathol Microbiol ; 47(1): 90-3, 2004 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15471146

RESUMO

Rotavirus is now established as an important cause of childhood diarrhoea throughout the world. Despite the availability of more advanced techniques for HRV characterization, electropherotyping was employed in this study to demonstrate the occurrence of diverse electropherotypes & any aberrant types thereof in isolates from children with acute gastroenteritis in Delhi, keeping in mind the ease of availability, performance and discriminatory power. Faecal specimens from 1172 children suffering from acute gastroenteritis were subjected to enzyme linked immunosorbent assay (ELISA) and polyacrylamide gel electrophoresis (PAGE). A total of 158 rotavirus strains were detected and electropherotyped by PAGE. Rotavirus was detected in 13.48% of the samples. A total of 10 electropherotypic patterns were observed to be in circulation. There was predominance of the long type over the short type and long type G was the most common isolate. The present study highlights the simultaneous coexistence of different electropherotypes of Human rotavirus strains circulating in Delhi and stresses the need for constant monitoring of the genomic diversity resulting from extensive genomic variation among Rotaviruses.


Assuntos
Gastroenterite/virologia , Infecções por Rotavirus/virologia , Pré-Escolar , Gastroenterite/epidemiologia , Humanos , Índia/epidemiologia , Lactente , Recém-Nascido , Epidemiologia Molecular , RNA Viral/genética , RNA Viral/isolamento & purificação , Rotavirus/classificação , Rotavirus/genética , Infecções por Rotavirus/epidemiologia
17.
Indian J Pathol Microbiol ; 46(1): 127-8, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15027754

RESUMO

Serology is the mainstay of diagnosis in Dengue virus infection. Various rapid tests for antibody detection have been developed. They can prove to be important diagnostic tools especially in the field set up due to technical simplicity. We evaluated a Rapid immunochromatographic assay The rapid test was performed on acute phase sera collected from patients suspected to be suffering from Dengue fever/DHF. These samples were then tested by Dengue Duo Capture ELISA and compared The rapid test showed a good sensitivity for the detection of secondary dengue infection and thus can be a good screening tool.


Assuntos
Anticorpos Antivirais/sangue , Dengue/diagnóstico , Fitas Reagentes , Cromatografia , Ensaio de Imunoadsorção Enzimática , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue
19.
Free Radic Biol Med ; 48(2): 207-15, 2010 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-19854263

RESUMO

Antimicrobial defense by neutrophils implicates the production of reactive oxygen species. Neutrophil responses can be modulated by agonists such as bacterial peptides and proinflammatory factors that modulate neutrophil activity and survival. We evaluated the production of superoxide anions (O(2)(-)) in response to fMLF by normal human neutrophils after 3 days of preincubation with GM-CSF + IL-4 + TNF-alpha (survival medium). After 3 days of incubation in survival medium, long-lived neutrophils produced up to six times more O(2)(-) relative to control neutrophils in response to fMLF and WKYMVM. This augmented response to fMLF was preferentially linked to formyl peptide receptor (FPR), whereas the response to WKYMVM was dependent on formyl peptide receptor-like 1 (FPRL-1). Real-time RT-PCR revealed a diminution of FPR and FPRL-1 expression in neutrophils incubated in survival medium. fMLF-induced overproduction of O(2)(-) by long-lived neutrophils was independent of intracellular calcium mobilization. The protein tyrosine phosphorylation profile of long-lived neutrophils was modified with respect to control cells. Pharmacological inhibitors of intracellular signals indicated that mechanisms of the excessive fMLF-induced production of O(2)(-) by long-lived neutrophils implicated the protein kinase C (PKC) pathway, preferentially the PKC-delta isoform, whose protein was augmented in these cells. Thus, long-term cytokine exposure modifies molecular pathways and functional characteristics of the neutrophil.


Assuntos
Citocinas/imunologia , N-Formilmetionina Leucil-Fenilalanina/farmacologia , Neutrófilos/metabolismo , Proteína Quinase C-delta/metabolismo , Superóxidos/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/imunologia , Células Cultivadas , Regulação para Baixo/imunologia , Humanos , Imunidade Inata , Ativação de Neutrófilo/efeitos dos fármacos , Neutrófilos/efeitos dos fármacos , Neutrófilos/imunologia , Neutrófilos/patologia , Oligopeptídeos/farmacologia , Proteína Quinase C-delta/imunologia , Receptores de Formil Peptídeo/genética , Receptores de Formil Peptídeo/imunologia , Receptores de Formil Peptídeo/metabolismo , Receptores de Lipoxinas/genética , Receptores de Lipoxinas/imunologia , Receptores de Lipoxinas/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/imunologia , Superóxidos/imunologia
20.
Endocrinology ; 151(3): 1367-74, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20080869

RESUMO

Oxytocin (OT) triggers the luteolytic pulses of prostaglandin F(2 alpha) (PGF(2 alpha)) from the endometrial epithelial cells in ruminants. We have proposed that the embryonic signal interferon-tau exerts its antiluteolytic effect by disrupting the OT signaling axis. Accordingly, we have attempted to define the signaling pathway of OT-induced PGF(2 alpha) production in the bovine endometrium using our newly characterized epithelial cell line (bEEL). OT receptor was coupled to the classical G alpha(q) pathway as evidenced by calcium release and activation of phospholipase C. Similarly, OT-induced PGF(2 alpha) production was mediated through the canonical ERK1/2 pathway. Because of the importance of receptor and nonreceptor tyrosine kinases in G protein-coupled receptor signaling, we studied the role of epidermal growth factor receptor (EGFR), c-Src, and phosphoinositide 3-kinase (PI3K) on OT-induced PGF(2 alpha) production in association with cyclooxygenase 2 (COX2) expression and ERK1/2 and Akt phosphorylation. The EGFR inhibitor AG1478 (10 microm) nearly abolished basal and OT-induced PGF(2 alpha) production and down-regulated COX2 expression and ERK1/2 phosphorylation. Because the transactivated EGFR can serve as a ligand for the signaling proteins with Src homology 2 (SH2) domain, we hypothesized a role for c-Src and PI3K in OT-induced PGF(2 alpha) production. Inhibitors of c-Src (PP2, 10 microm) and PI3K (LY294002, 25 microm) produced a significant decrease in OT-induced PGF(2 alpha) production and reduced COX2 expression. Also, PP2, but not LY294002, decreased OT-induced ERK1/2 phosphorylation. Because LY294002 did not affect ERK1/2 phosphorylation, but inhibited PGF(2 alpha) production and down-regulated COX2 expression, it is likely that the Akt pathway is also involved in PGF(2 alpha) production. Thus, EGFR may simultaneously activate c-Src and PI3K to amplify the OT signaling to increase the output of PGF(2 alpha) in bEEL cells.


Assuntos
Ciclo-Oxigenase 2/metabolismo , Dinoprosta/metabolismo , Endométrio/metabolismo , Receptores ErbB/metabolismo , Ocitocina/metabolismo , Animais , Proteína Tirosina Quinase CSK , Cálcio/metabolismo , Bovinos , Linhagem Celular , Células Epiteliais/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Feminino , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/metabolismo , Líquido Intracelular/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Fosforilação , Proteínas Tirosina Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptores de Ocitocina/metabolismo , Transdução de Sinais , Fosfolipases Tipo C/metabolismo , Quinases da Família src
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA