Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 74
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Cell Microbiol ; 18(1): 66-79, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26153406

RESUMO

Vascular injury is a serious complication of sepsis due to the gram-negative bacterium Neisseria meningitidis. One of the critical early steps in initiating this injury is via the interaction of leucocytes, particularly neutrophils, with adhesion molecules expressed on inflamed endothelium. We have previously demonstrated that both lipopolysaccharide (LPS) and non-LPS components of meningococci can induce very high levels of expression of the vascular endothelial cell adhesion molecule E-selectin, which is critical for early tethering and capture of neutrophils onto endothelium under flow. Using an LPS-deficient strain of meningococcus, we showed that very high levels of expression can be induced in primary endothelial cells, even in the context of weak activation of the major host signal transduction factor [nuclear factor-κB (NF-κB)]. In this study, we show that the particular propensity for N. meningitidis to induce high levels of expression is regulated at a transcriptional level, and demonstrate a significant role for phosphorylation of the ATF2 transcription factor, likely via mitogen-activated protein (MAP) kinases, on the activity of the E-selectin promoter. Furthermore, inhibition of E-selectin expression in response to the lpxA- strain by a p38 inhibitor indicates a significant role of a p38-dependent MAPK signalling pathway in ATF2 activation. Collectively, these data highlight the role that LPS and other bacterial components have in modulating endothelial function and their involvement in the pathogenesis of meningococcal sepsis. Better understanding of these multiple mechanisms induced by complex stimuli such as bacteria, and the specific inflammatory pathways they activate, may lead to improved, focused interventions in both meningococcal and potentially bacterial sepsis more generally.


Assuntos
Fator 2 Ativador da Transcrição/metabolismo , Selectina E/metabolismo , Células Endoteliais/microbiologia , Células Endoteliais/fisiologia , Interações Hospedeiro-Patógeno , Neisseria meningitidis/fisiologia , Células Cultivadas , Endotoxinas/metabolismo , Humanos
2.
Br J Surg ; 99(7): 929-38, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22513659

RESUMO

BACKGROUND: Addition of glutamine to parenteral nutrition in surgical infants remains controversial. The aim of this trial was to determine whether glutamine supplementation of parenteral nutrition in infants requiring surgery would reduce the time to full enteral feeding and/or decrease the incidence of sepsis and septicaemia. METHODS: A prospective double-blind multicentre randomized clinical trial was performed in surgical infants less than 3 months old who required parenteral nutrition. Patients were allocated to treatment or control groups by means of minimization. Infants received either 0·6 g per kg per day alanyl-glutamine (treatment group) or isonitrogenous isocaloric parenteral nutrition (control group) until full enteral feeding was achieved. Primary outcomes were time to full enteral feeding and incidence of sepsis. Cox regression analysis was used to compare time to full enteral feeding, and to calculate risk of sepsis/septicaemia. RESULTS: A total of 174 patients were randomized, of whom 164 completed the trial and were analysed (82 in each group). There was no difference in time to full enteral feeding or time to first enteral feeding between groups, and supplementation with glutamine had no effect on the overall incidence of sepsis or septicaemia. However, during total parenteral nutrition (before the first enteral feed), glutamine administration was associated with a significantly decreased risk of developing sepsis (hazard ratio 0·33, 95 per cent confidence interval 0·15 to 0·72; P = 0·005). CONCLUSION: Glutamine supplementation during parenteral nutrition did not reduce the incidence of sepsis in surgical infants with gastrointestinal disease. REGISTRATION NUMBER: ISRCTN83168963 (http://www.controlled-trials.com).


Assuntos
Suplementos Nutricionais , Gastroenteropatias/cirurgia , Glutamina/administração & dosagem , Nutrição Parenteral/métodos , Peso Corporal , Método Duplo-Cego , Ingestão de Energia , Feminino , Gastroenteropatias/dietoterapia , Humanos , Lactente , Recém-Nascido , Masculino , Modelos de Riscos Proporcionais , Estudos Prospectivos , Sepse/prevenção & controle
3.
Arthritis Rheum ; 62(6): 1770-80, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20178138

RESUMO

OBJECTIVE: Endothelial injury is central to the pathogenesis of vasculitis. The purpose of this study was to assess how indices of endothelial injury and repair change during different stages of disease activity in children with primary systemic vasculitis (PSV). METHODS: Fifty children with PSV, 17 children with nonvasculitic inflammatory diseases (pediatric inflammatory disease controls), 35 healthy age- and sex-matched pediatric controls, and 27 healthy adult controls were included in the study. Biomarkers examined were endothelial microparticles (EMPs), circulating endothelial cells (CECs), angiogenic growth factors, and endothelial progenitor cells (EPCs). EMP binding to annexin V, EMPs expressing CD144 or E-selectin, and EPCs expressing vascular endothelial growth factor receptor 2 (VEGFR-2), CD133, and CD34 were examined by flow cytometry. CECs were enumerated using immunomagnetic bead extraction techniques, and VEGF and angiopoietin 2 (Ang-2) were measured by enzyme-linked immunosorbent assay. RESULTS: Levels of CD144+ EMPs, CECs, VEGF, and EPCs were all significantly elevated in children with active vasculitis as compared with healthy children, and the levels declined with remission-inducing therapy in the individual patients. Treatment-naive patients with active disease had significantly higher levels of VEGF and Ang-2 than did those with active disease who were receiving treatment, although the levels of CECs and EMPs remained high in both of these groups. CONCLUSION: Elevation of the levels of CECs, EMPS, EPCs, VEGF, and Ang-2 occurs during active vasculitis in children. EPC responses to active vasculitis are different in children as compared with that observed in adults with vasculitis, and both CECs and EMPs can be used to monitor disease activity in children with vasculitis.


Assuntos
Micropartículas Derivadas de Células/patologia , Células Endoteliais/patologia , Vasculite Sistêmica/patologia , Adolescente , Adulto , Antígenos CD/imunologia , Antígenos CD/metabolismo , Caderinas/imunologia , Caderinas/metabolismo , Micropartículas Derivadas de Células/imunologia , Micropartículas Derivadas de Células/metabolismo , Criança , Pré-Escolar , Estudos Transversais , Células Endoteliais/imunologia , Células Endoteliais/metabolismo , Endotélio Vascular/imunologia , Endotélio Vascular/metabolismo , Endotélio Vascular/patologia , Feminino , Humanos , Lactente , Estudos Longitudinais , Masculino , Seleção de Pacientes , Índice de Gravidade de Doença , Células-Tronco/imunologia , Células-Tronco/metabolismo , Vasculite Sistêmica/imunologia , Vasculite Sistêmica/metabolismo , Fator A de Crescimento do Endotélio Vascular/sangue
4.
Forensic Sci Med Pathol ; 7(2): 141-7, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21063809

RESUMO

Around two thirds of sudden unexpected deaths in infancy (SUDI) remain unexplained following post-mortem examination. It has been postulated that a subset of unexplained SUDI may be caused by toxigenic Staphylococcus aureus. The aim of this study was to compare the prevalence of toxigenic S aureus strains in unexplained and explained SUDI (those in whom a cause of death is determined at autopsy). A retrospective review was performed of 546 SUDI autopsies as part of a larger review of >1,500 pediatric autopsies over a 10-year period, 1996-2005 inclusive. SUDI was defined as the sudden and unexpected death of an infant aged 7-365 days, and categorized into unexplained, explained with histological evidence of infection (bacterial infection group) or explained due to non-infective causes. Toxin gene profiling was carried out by PCR in cases in whom S aureus was isolated as part of clinical investigation. Of the 507 SUDI included in this analysis, bacteriological investigations were performed in 470, and S aureus was isolated on post-mortem culture from at least one site in 173 (37%). There were significantly more cases with S aureus isolated in unexplained SUDI (40%) compared to non-infective SUDI (21%; difference 19.0%, 95% CI 5.4% to 29.3%, P = 0.006). 46% of all cases with S aureus isolated underwent routine testing for a panel of staphylococcal toxin genes (including SEA to SEE, SEG to SEJ, TSST-1, and exfoliative toxins A and B). There were more cases with at least one toxigenic strain of S aureus in the unexplained SUDI (81%) and bacterial infection groups (77%) than in the non-infection group (63%), but these differences were not statistically significant (Fisher exact test, P = 0.44). Toxin gene-carrying S aureus is commonly detected at autopsy in SUDI, accounting for 78% of S aureus isolates submitted for toxin gene profiling in this series. There is a significantly higher prevalence of S aureus in unexplained SUDI compared to non-infective SUDI, but no significant difference in the proportion with toxigenic S aureus strains isolated between the groups. These data are consistent with the hypothesis that a subset of otherwise unexplained SUDI may be related to the presence of S aureus colonization/infection, but do not indicate routine testing for toxin-associated genotypes.


Assuntos
Autopsia/estatística & dados numéricos , Sepse/epidemiologia , Infecções Estafilocócicas/epidemiologia , Staphylococcus aureus/isolamento & purificação , Morte Súbita do Lactente/epidemiologia , Toxinas Bacterianas/isolamento & purificação , Hospitais Pediátricos/estatística & dados numéricos , Humanos , Lactente , Recém-Nascido , Londres/epidemiologia , Prevalência , Estudos Retrospectivos , Sepse/microbiologia
5.
Lancet ; 371(9627): 1848-53, 2008 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-18514728

RESUMO

BACKGROUND: The cause and mechanism of most cases of sudden unexpected death in infancy (SUDI) remain unknown, despite specialist autopsy examination. We reviewed autopsy results to determine whether infection was a cause of SUDI. METHODS: We did a systematic retrospective case review of autopsies, done at one specialist centre between 1996 and 2005, of 546 infants (aged 7-365 days) who died suddenly and unexpectedly. Cases of SUDI were categorised as unexplained, explained with histological evidence of bacterial infection, or explained by non-infective causes. Microbial isolates gathered at autopsy were classified as non-pathogens, group 1 pathogens (organisms usually associated with an identifiable focus of infection), or group 2 pathogens (organisms known to cause septicaemia without an obvious focus of infection). FINDINGS: Of 546 SUDI cases, 39 autopsies were excluded because of viral or pneumocystis infection or secondary bacterial infection after initial collapse and resuscitation. Bacteriological sampling was done in 470 (93%) of the remaining 507 autopsies. 2079 bacteriological samples were taken, of which 571 (27%) were sterile. Positive cultures yielded 2871 separate isolates, 484 (32%) of which showed pure growth and 1024 (68%) mixed growth. Significantly more isolates from infants whose deaths were explained by bacterial infection (78/322, 24%) and from those whose death was unexplained (440/2306, 19%) contained group 2 pathogens than did those from infants whose death was explained by a non-infective cause (27/243, 11%; difference 13.1%, 95% CI 6.9-19.2, p<0.0001 vs bacterial infection; and 8.0%, 3.2-11.8, p=0.001 vs unexplained). Significantly more cultures from infants whose deaths were unexplained contained Staphylococcus aureus (262/1628, 16%) or Escherichia coli (93/1628; 6%) than did those from infants whose deaths were of non-infective cause (S aureus: 19/211, 9%; difference 7.1%, 95% CI 2.2-10.8, p=0.005; E coli: 3/211, 1%, difference 4.3%, 1.5-5.9, p=0.003). INTERPRETATION: Although many post-mortem bacteriological cultures in SUDI yield organisms, most seem to be unrelated to the cause of death. The high rate of detection of group 2 pathogens, particularly S aureus and E coli, in otherwise unexplained cases of SUDI suggests that these bacteria could be associated with this condition.


Assuntos
Infecções Bacterianas/complicações , Escherichia coli/isolamento & purificação , Staphylococcus aureus/isolamento & purificação , Morte Súbita do Lactente/etiologia , Autopsia , Infecções Bacterianas/classificação , Escherichia coli/patogenicidade , Humanos , Lactente , Recém-Nascido , Estudos Retrospectivos , Staphylococcus aureus/patogenicidade
6.
Thorax ; 64(2): 150-5, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18988662

RESUMO

BACKGROUND: Mannose-binding lectin (MBL) deficiency has been associated with infections of the respiratory tract and with increased disease severity in cystic fibrosis (CF). The mechanism is uncertain, and could relate either to systemic or local effects. The aim of this study was to determine, in a large cohort of children, whether MBL is present on the airway surface in health or disease. METHODS: Bronchoalveolar lavage (BAL) fluid from children with and without respiratory infection (some with underlying disease) was analysed for MBL and neutrophil elastase (NE). Levels were compared between groups, and correlations were examined with local and systemic inflammatory markers, infective organisms and load. RESULTS: 85 children were recruited to the study. MBL was absent in the lavage of all 7 children without lung infection but present in 62% (8/13) of those with acute pneumonia/pneumonitis, 23% (5/22) with recurrent respiratory tract infections, 17% (1/6) with primary ciliary dyskinesia and 8% (3/37) with CF (p<0.01). Children with acute pneumonia/pneumonitis had significantly higher levels than those in the other groups. There was no relationship with organisms cultured or systemic markers of inflammation, although in the group with detectable MBL in the BAL fluid, the levels correlated positively with levels of NE. CONCLUSIONS: MBL is undetectable in the non-infected airway but is present in a significant number of samples from children with lung infection. The levels found in the BAL fluid could be physiologically active and the protein may therefore be playing a role in host defence.


Assuntos
Brônquios/química , Broncopatias/metabolismo , Líquido da Lavagem Broncoalveolar/química , Lectina de Ligação a Manose/metabolismo , Infecções Respiratórias/metabolismo , Adolescente , Bactérias/isolamento & purificação , Broncopatias/microbiologia , Líquido da Lavagem Broncoalveolar/microbiologia , Criança , Pré-Escolar , Estudos de Coortes , Ensaio de Imunoadsorção Enzimática , Feminino , Genótipo , Haplótipos , Humanos , Lactente , Elastase de Leucócito/metabolismo , Masculino , Inibidores de Proteases/farmacologia , Recidiva , Infecções Respiratórias/microbiologia , Vírus/isolamento & purificação
7.
Intensive Care Med ; 32(2): 286-294, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16450100

RESUMO

BACKGROUND: The systemic inflammatory response syndrome (SIRS) may be triggered by endotoxin. Humans have antibodies directed against the core of endotoxin (endotoxin core antibodies, EndoCAb) that appear to be protective following surgery and in sepsis. We hypothesised that children with elevated antibodies to endotoxin core would be less likely to develop SIRS in their initial period on intensive care. Because of the existing literature we defined two sub-groups according to the primary reason for ICU admission: infection and non-infection. METHODS: We recruited 139 consecutive patients admitted to a paediatric intensive care unit (PICU) with more than one organ failure for longer than 12 h as part of another study. Patients were classified on admission to PICU as having an infectious or a non-infections diagnosis. The occurrence of SIRS within 48 h of admission was recorded along with detailed clinical and demographic data, EndoCAb concentration and the potential confounding variables C-reactive protein and mannose-binding lectin. RESULTS: In the 71 patients admitted without infection (primarily post-operative and head injured) IgG EndoCAb was significantly lower in patients who developed SIRS than those who did not (72 vs. 131 MU/ml), independent of potential confounding variables. In patients with infection there was no significant difference in IgG EndoCAb between children developing SIRS and those who did not (111 vs. 80 MU/ml). CONCLUSION: Head injured and post-operative patients admitted to PICU who develop early SIRS have significantly lower serum IgG EndoCAb levels than those who do not.


Assuntos
Estado Terminal , Endotoxemia/complicações , Endotoxemia/imunologia , Síndrome de Resposta Inflamatória Sistêmica/etiologia , Síndrome de Resposta Inflamatória Sistêmica/imunologia , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Fatores de Risco , Estatísticas não Paramétricas , Síndrome de Resposta Inflamatória Sistêmica/sangue
8.
Mol Immunol ; 42(8): 919-24, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15829282

RESUMO

Mannose-binding lectin (MBL) deficiency has now been recognised for 15 years. Numerous studies have shown that MBL deficiency is associated with an increased susceptibility to a range of infections. However, the importance of MBL, in defence against infection, is still debated. This article discusses recent developments in MBL research and explores how MBL may be operating in the setting of modern medical practice.


Assuntos
Lectina de Ligação a Manose/deficiência , Lectina de Ligação a Manose/fisiologia , Animais , HIV/imunologia , Humanos , Inflamação/imunologia , Lectina de Ligação a Manose/imunologia , Neutropenia/imunologia
9.
J Leukoc Biol ; 73(6): 722-30, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12773504

RESUMO

Approximately 25% of polymorphonuclear leukocytes (PMNL) circulate in heterotypic complexes with one or more activated platelets. These platelet-neutrophil complexes (PNC) require platelet CD62P expression for their formation and represent activated subpopulations of both cell types. In this study, we have investigated the presence, time course, and mechanisms of PNC formation in 32 cases of severe pediatric meningococcal disease (MD) requiring intensive care. There were marked early increases in PMNL CD11b/CD18 expression and activation, and reduced CD62L expression compared with intensive care unit control cases. Minimal platelet expression of the active form of alphaIIbbeta3 (GpIIb/IIIa) was seen. PNC were reduced on presentation and fell to very low levels after 24 h. Immunostaining of skin biopsies demonstrated that PNC appear outside the circulation in MD. In vitro studies of anticoagulated whole blood inoculated with Neisseria meningitidis supported these clinical findings with marked increases in PMNL CD11b/CD18 expression and activation but no detectable changes in platelet-activated alphaIIbbeta3 or CD62P expression. In vitro PMNL activation with N. meningitidis (or other agonists) potentiated the formation of PNC in response to platelet activation with adenine diphosphate. Therefore, in severe MD, PMNL activation is likely to promote PNC formation, and we suggest that the reduced levels of PNC seen in established MD reflect rapid loss of PNC from the circulation rather than reduced formation.


Assuntos
Plaquetas/fisiologia , Infecções Meningocócicas/imunologia , Infecções Meningocócicas/fisiopatologia , Ativação de Neutrófilo , Neutrófilos/imunologia , Antígenos CD/análise , Antígenos CD/imunologia , Antígenos de Diferenciação Mielomonocítica/análise , Antígenos de Diferenciação Mielomonocítica/imunologia , Biópsia , Sangue , Plaquetas/citologia , Adesão Celular , Moléculas de Adesão Celular/metabolismo , Pré-Escolar , Humanos , Imuno-Histoquímica , Lactente , Recém-Nascido , Integrinas/metabolismo , Cinética , Substâncias Macromoleculares , Infecções Meningocócicas/diagnóstico , Neutrófilos/citologia , Ativação Plaquetária , Contagem de Plaquetas , Transfusão de Plaquetas , Pele/patologia
10.
Int J Dev Biol ; 42(5): 663-74, 1998 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9712521

RESUMO

Tumor necrosis factor-alpha (TNF-alpha), an inflammatory cytokine, has diverse actions both within and outside the immune system and has been implicated in the etiology of a wide range of pathological conditions. Evidence is accumulating that it may also have important roles in the normal development of the embryo. In this study we demonstrated that the addition of recombinant TNF-alpha to metanephric organ culture induced a dose dependent and reversible decrease in growth and development, with inhibition of ureteric bud branching and nephron formation beyond the condensate stage and despite appropriate expression of the transcription factor pax-2. TNF-alpha also increased the point prevalence of apoptosis after only 1 day of culture. We also noted that macrophages were present in renal rudiments at the inception of nephrogenesis and their numbers significantly increased during the culture period. This effect was enhanced by TNF-alpha. We have also demonstrated expression of mRNAs for TNF-alpha and its receptors in whole mouse metanephroi from the inception of renal development. TNF-alpha protein was also detected, predominantly at mesenchymal/epithelial interfaces. In addition, TNF-alpha mRNA and protein were expressed by clonal renal mesenchymal cells in vitro, suggesting that these cells are a source of TNF-alpha in vivo.


Assuntos
Regulação da Expressão Gênica no Desenvolvimento , Rim/embriologia , Fator de Necrose Tumoral alfa/genética , Animais , Western Blotting , Diferenciação Celular/efeitos dos fármacos , Ensaio de Imunoadsorção Enzimática , Rim/citologia , Camundongos , Morfogênese , Néfrons/citologia , Néfrons/embriologia , Técnicas de Cultura de Órgãos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fator de Necrose Tumoral alfa/farmacologia
11.
J Immunol Methods ; 209(2): 125-35, 1997 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-9461329

RESUMO

Evidence is increasing that platelets can initiate and propagate inflammatory processes by interacting with leucocytes and the vascular endothelium. Platelets have been shown to bind to neutrophils, existing as platelet/neutrophil complexes (PNC) within the circulation. We describe a simple flow cytometric method for assessing and investigating platelet interactions with neutrophils in small volumes of whole blood. Twenty-five percent (sd 6%) of circulating neutrophils from healthy adults were associated with platelets. Formation of these platelet-neutrophil complexes was CD62P (P-selectin) and divalent cation dependent. Platelet activation (with ADP or thrombin) caused a rapid and sustained rise in %PNC which differed from the pattern of free platelet activation as assessed by CD62P expression. F-met-leu-phe induced neutrophil activation but did not increase the percentage PNC. Platelet activation also caused increased neutrophil CD11b/CD18 expression which was most marked on neutrophils complexed with platelets. This straightforward technique is simple, reproducible, and allows assessment of platelet-neutrophil interactions and activation of neutrophils. It may also provide a method for estimating platelet activation in whole blood.


Assuntos
Plaquetas/citologia , Citometria de Fluxo/métodos , Neutrófilos/citologia , Adulto , Plaquetas/efeitos dos fármacos , Humanos , N-Formilmetionina Leucil-Fenilalanina/farmacologia , Selectina-P/biossíntese , Ativação Plaquetária
12.
J Immunol Methods ; 202(1): 67-75, 1997 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-9075773

RESUMO

An enzyme-linked immunosorbent assay (ELISA) has been developed to measure cellular fibronectin (cFN) in association with human umbilical vein endothelial cells (HUVEC) in culture. The expression of a number of functional domains on the cFN molecule was demonstrated using three specific murine monoclonal antibodies. This system was found to be sensitive, detecting as little as 0.156 microg/ml of cFN, and required only 1.3 x 10(5) cells per well confluent cells per experimental condition. This allowed multiple experiments to be performed on one batch of endothelial cells. cFN was detected on both viable and methanol fixed endothelial cells without significant non-specific antibody binding. The utility of this experimental model was studied by exploring the effect of urokinase activated plasminogen, a potent protease, on the expression of cFN and its functional domains.


Assuntos
Endotélio Vascular/metabolismo , Fibronectinas/biossíntese , Fibronectinas/metabolismo , Plasminogênio/farmacologia , Anticorpos Monoclonais/farmacologia , Células Cultivadas , Endotélio Vascular/imunologia , Ativação Enzimática , Ensaio de Imunoadsorção Enzimática , Fibronectinas/imunologia , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Coloração e Rotulagem , Veias Umbilicais
13.
Brain Res ; 830(2): 330-6, 1999 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-10366690

RESUMO

Adhesion molecules on the endothelial surface of the blood-brain barrier (BBB) play an important role in the pathogenesis of many encephalopathies, including multiple sclerosis (MS) and cerebral malaria (CM). The expression of four surface molecules of relevance to MS and CM on the immortalized human umbilical vein endothelial cell line, ECV304, was investigated using immunofluorescence flow cytometry. We found that ECV304 cells express intercellular adhesion molecule-1 (ICAM-1) and low levels of CD36, but not vascular cell adhesion molecule-1 (VCAM-1) or E-selectin. This expression pattern was unaltered on ECV304 cells which were co-cultured with C6 glioma cells; conditions under which the endothelial cells display enhanced barrier formation. Tumour necrosis factor-alpha (TNF-alpha), which is elevated in MS and CM, decreased the integrity of the barrier in co-cultured endothelial cells and upregulated the expression of ICAM-1 nine-fold. The significance of elevated ICAM-1 expression in relation to the binding of parasitised erythrocytes at the BBB in CM is discussed.


Assuntos
Barreira Hematoencefálica/efeitos dos fármacos , Endotélio Vascular/efeitos dos fármacos , Molécula 1 de Adesão Intercelular/metabolismo , Fator de Necrose Tumoral alfa/farmacologia , Animais , Antígenos CD36/análise , Linhagem Celular , Selectina E/metabolismo , Endotélio Vascular/citologia , Endotélio Vascular/metabolismo , Citometria de Fluxo , Humanos , Ratos , Células Tumorais Cultivadas , Regulação para Cima , Molécula 1 de Adesão de Célula Vascular/metabolismo
14.
Thromb Res ; 67(6): 677-85, 1992 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-1440532

RESUMO

The processes that underlie the coagulopathy observed in severe infection are not fully understood, but seem to be due to an imbalance in the antithrombotic, and prothrombotic properties of the vascular endothelium. Sulphated glycosaminoglycans (GAGs) present on the vessel wall represent an important component of the non-thrombogenic nature of the endothelium. We have modified an amidolytic assay to study the functional ability of GAGs on human umbilical vein endothelial cells (HUVECS), and investigate the effect of E. coli endotoxin and neutrophils on HUVEC surface anticoagulant activity (SAA). Neither endotoxin alone, nor separated neutrophils at lower concentrations (less than 10(6) neutrophils per ml), had major effects on endothelial SAA. When activated neutrophils were incubated with HUVECS pre-stimulated with endotoxin, a significant decrease in SAA was seen using either plasma (mean percentage of control 67.8% +/- sem 7.8; p < 0.02) or purified ATIII (mean percentage of control 69% +/- sem 4.6; p < 0.001). We suggest that alterations in endothelial surface GAGs may occur during sepsis and inflammation, and that this may have important consequences for vascular function. This system will allow the further study of the role of GAGs in the intravascular thrombosis of severe sepsis, and other inflammatory diseases.


Assuntos
Anticoagulantes/metabolismo , Endotélio Vascular/metabolismo , Glicosaminoglicanos/metabolismo , Antitrombina III/metabolismo , Células Cultivadas , Endotélio Vascular/efeitos dos fármacos , Endotoxinas/toxicidade , Cofator II da Heparina/metabolismo , Humanos , Técnicas In Vitro , Cinética , Neutrófilos/fisiologia , Trombose/etiologia
15.
Eur J Clin Nutr ; 57(4): 548-53, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12700616

RESUMO

BACKGROUND AND AIMS: Patients receiving parenteral nutrition are at risk of septicaemia. Intestinal dysmotility and impaired gut immunity due to parenteral nutrition promote bacterial overgrowth. Gut overgrowth with aerobic Gram-negative bacilli (AGNB) impairs systemic immunity. The aim of this study was to determine the potential role of gut overgrowth with AGNB in the pathogenesis of septicaemia related to parenteral nutrition. METHODS: A prospective 5 y study of surgical infants less than 6 months of age was undertaken. Surveillance samples of the oropharynx and gut were obtained at the start of parenteral nutrition and thereafter twice weekly, to detect AGNB carriage. Blood cultures were taken on clinical indication only. RESULTS: Two-hundred and eight infants received parenteral nutrition for 6271 days (median 13 days, range 1-512 days). The incidence of AGNB carriage was 42%, whilst the septicaemia rate was 15%. Eighty-four percent of septicaemic infants carried AGNB, whilst 16% never carried AGNB (P<0.005). Carriage developed significantly earlier than septicaemia. CONCLUSIONS: The incidence of septicaemia was significantly greater in the subset of abnormal carriers. Although gut overgrowth with abnormal flora reflects illness severity, the fact that it preceded septicaemia implicates AGNB overgrowth, per se, as a contributory factor in the development of septicaemia related to parenteral nutrition. Prevention is unlikely to be successful if it ignores the abnormal flora.


Assuntos
Infecções por Bactérias Gram-Negativas/etiologia , Enteropatias/cirurgia , Nutrição Parenteral/efeitos adversos , Bacteriemia/epidemiologia , Bacteriemia/microbiologia , Peso ao Nascer , Estudos de Coortes , Feminino , Idade Gestacional , Bactérias Aeróbias Gram-Negativas , Infecções por Bactérias Gram-Negativas/epidemiologia , Infecções por Bactérias Gram-Negativas/microbiologia , Humanos , Lactente , Recém-Nascido , Enteropatias/microbiologia , Enteropatias/terapia , Masculino , Estudos Prospectivos , Fatores de Tempo
16.
Methods Mol Med ; 67: 649-61, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-21337171

RESUMO

The vascular endothelium forms an essential barrier against invasion by Neisseria meningitidis from the nasopharynx into the circulation and against meningococcal invasion from the bloodstream into the brain. In previous chapters, there has therefore been considerable emphasis on techniques designed to investigate the mechanisms underlying meningococcal interactions with epithelial and endothelial surfaces. The vascular endothelium is also a major target for the host inflammatory response to meningococcal infection and indeed the ensuing endothelial damage underlies many of the clinical manifestations associated with this condition (1,2). For this reason, our work has focused on understanding the cellular and molecular consequences of meningococcalendothelial interactions.

17.
J Pediatr Surg ; 34(2): 242-5, 1999 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10052796

RESUMO

BACKGROUND: Studies have shown that total parenteral nutrition (TPN) in infancy is associated with impaired immunity. The causes of this acquired immunodeficiency are poorly understood. Bacterial infection is a major complication of TPN suggesting neutrophils may be affected by this feeding modality. PURPOSE: The aim of this study was to test the hypothesis that TPN-related impaired bactericidal activity is related to impairment of neutrophil function, particularly intracellular killing. METHODS: Studies were performed in five infants (age <2 months) who received long-term TPN (>10 days), five control infants who received a normal enteral diet, and five healthy adults. Patients on long-term TPN were clinically stable with no evidence of sepsis. The experimental study used an in vitro whole-blood model of septicaemia. Coagulase-negative staphylococci were the bacterial challenge. Whole-blood killing of coagulase-negative staphylococci was measured after 45 minutes using the Miles-Misra technique. Neutrophils were separated from whole blood after 15, 30, 45, and 60 minutes of bacterial challenge. The survival rate of the bacteria within the neutrophils was analysed by flow cytometry and the percentage of the bacteria killed by neutrophil intracellular killing assessed at each time-point. RESULTS: Whole-blood killing was significantly lower (P = .05) in infants who received long-term TPN (33.3%) compared with control infants (69.7%) and adults (67.7%). In all subjects studied, neutrophil intracellular killing increased with incubation time. At each time point the intracellular killing in infants on long-term TPN was significantly lower (P < .05) than in normal control infants and adults. CONCLUSION: Future strategies to prevent TPN-related infection should aim to minimise this acquired neutrophil dysfunction.


Assuntos
Atividade Bactericida do Sangue/imunologia , Neutrófilos/imunologia , Nutrição Parenteral Total/efeitos adversos , Adulto , Bacteriemia/imunologia , Citometria de Fluxo , Humanos , Lactente , Recém-Nascido , Staphylococcus/imunologia , Estatísticas não Paramétricas
18.
J Pediatr Surg ; 34(2): 277-80, 1999 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10052804

RESUMO

BACKGROUND/PURPOSE: Previous studies have shown that total parenteral nutrition (TPN) influences host immunity, but the mechanism is unclear. This study explored the effect of TPN solution on neutrophil phagocytosis and whole-blood cytokine production in response to coagulase-negative staphylococci in vitro challenge. METHODS: Blood samples were taken from five enterally fed infants (age <6 months) and six healthy adults. Samples were incubated for 45 minutes with four isovolemic solutions: (A) control (saline), (B) TPN (0.1 microL/mL of blood), (C) TPN (1 microL/mL), (D) TPN (10 microL/mL). Solution C (1 microL/mL) corresponded to TPN-blood ratio used in clinical practice. After incubation, blood was challenged with coagulase-negative staphylococci. Neutrophil phagocytosis was measured by flow cytometry after 40 minutes of bacterial challenge, and tumour necrosis factor alpha (TNF-alpha) was measured by enzyme-linked immunosorbent assay (ELISA) after 2 hours of bacterial challenge. RESULTS: In infant blood, TNF-alpha production after coagulase-negative staphylococci challenge was impaired after the addition of a "physiological" dose of TPN solution (1 microL/mL of blood) as well as "supranormal" doses (10 microL/mL of blood). In adult blood, a similar effect was observed only after the addition of a supranormal dose of TPN. In both the infant and adult blood, there was no direct effect of TPN solution on neutrophil phagocytosis. CONCLUSIONS: These results suggest that infants are more susceptible than adults to TPN-related depression of cytokine production. The level of proinflammatory cytokines may be important in the host defence against bacterial infection.


Assuntos
Nutrição Parenteral Total/efeitos adversos , Fator de Necrose Tumoral alfa/metabolismo , Adulto , Atividade Bactericida do Sangue/imunologia , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Humanos , Lactente , Neutrófilos/imunologia , Fagocitose/fisiologia , Staphylococcus/imunologia , Estatísticas não Paramétricas
19.
Urol Nurs ; 21(2): 71-6; quiz 81-2, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11998288

RESUMO

Most parents believe that their child should not be wetting the bed by age 5. Statistics show that 10% to 20% of 5 year olds continue with a least one episode of nocturnal enuresis per month. There is evidence that successful treatment leads to improved self-concept in children (Moffatt, Kato, & Pless, 1987). Treatment consists of various behavior modifications or pharmacologic regimes. Nurses and nurse practitioners in family practice, pediatric practice, school health, and urologic practice are in ideal roles to seek out and manage children with primary nocturnal enuresis.


Assuntos
Enurese/enfermagem , Criança , Diagnóstico Diferencial , Enurese/diagnóstico , Enurese/epidemiologia , Enurese/etiologia , Humanos , Avaliação em Enfermagem , Prevalência
20.
Arch Dis Child ; 99(1): 74-83, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24162006

RESUMO

Kawasaki disease (KD) is an acute self-limiting inflammatory disorder, associated with vasculitis, affecting predominantly medium-sized arteries, particularly the coronary arteries. In developed countries KD is the commonest cause of acquired heart disease in childhood. The aetiology of KD remains unknown, and it is currently believed that one or more as yet unidentified infectious agents induce an intense inflammatory host response in genetically susceptible individuals. Genetic studies have identified several susceptibility genes for KD and its sequelae in different ethnic populations, including FCGR2A, CD40, ITPKC, FAM167A-BLK and CASP3, as well as genes influencing response to intravenous immunoglobulin (IVIG) and aneurysm formation such as FCGR3B, and transforming growth factor (TGF) ß pathway genes. IVIG and aspirin are effective therapeutically, but recent clinical trials and meta-analyses have demonstrated that the addition of corticosteroids to IVIG is beneficial for the prevention of coronary artery aneurysms (CAA) in severe cases with highest risk of IVIG resistance. Outside of Japan, however, clinical scores to predict IVIG resistance perform suboptimally. Furthermore, the evidence base does not provide clear guidance on which corticosteroid regimen is most effective. Other therapies, including anti-TNFα, could also have a role for IVIG-resistant KD. Irrespective of these caveats, it is clear that therapy that reduces inflammation in acute KD, improves outcome. This paper summarises recent advances in the understanding of KD pathogenesis and therapeutics, and provides an approach for managing KD patients in the UK in the light of these advances.


Assuntos
Corticosteroides/uso terapêutico , Imunoglobulinas Intravenosas/uso terapêutico , Síndrome de Linfonodos Mucocutâneos/terapia , Pré-Escolar , Aneurisma Coronário/prevenção & controle , Humanos , Síndrome de Linfonodos Mucocutâneos/diagnóstico , Síndrome de Linfonodos Mucocutâneos/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA