Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 129
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Arch Biochem Biophys ; 663: 239-248, 2019 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-30659802

RESUMO

Mitochondrial reactive oxygen species (ROS) are important cellular signaling molecules, but can cause oxidative damage if not kept within tolerable limits. An important proximal form of ROS in mitochondria is superoxide. Its production is thought to occur in regulated stochastic bursts, but current methods using mitochondrial targeted cpYFP to assess superoxide flashes are confounded by changes in pH. Accordingly, these flashes are generally referred to as 'mitoflashes'. Here we provide regulatory insights into mitoflashes and pH fluctuations in skeletal muscle, and the role of uncoupling protein-3 (UCP3). Using quantitative confocal microscopy of mitoflashes in intact muscle fibers, we show that the mitoflash magnitude significantly correlates with the degree of mitochondrial inner membrane depolarization and ablation of UCP3 did not affect this correlation. We assessed the effects of the absence of UCP3 on mitoflash activity in intact skeletal muscle fibers, and found no effects on mitoflash frequency, amplitude or duration, with a slight reduction in the average size of mitoflashes. We further investigated the regulation of pH flashes (pHlashes, presumably a component of mitoflash) by UCP3 using mitochondrial targeted SypHer (mt-SypHer) in skeletal muscle fibers. The frequency of pHlashes was significantly reduced in the absence of UCP3, without changes in other flash properties. ROS scavenger, tiron, did not alter pHlash frequency in either WT or UCP3KO mice. High resolution respirometry revealed that in the absence of UCP3 there is impaired proton leak and Complex I-driven respiration and maximal coupled respiration. Total cellular production of hydrogen peroxide (H2O2) as detected by Amplex-UltraRed was unaffected. Altogether, we demonstrate a correlation between mitochondrial membrane potential and mitoflash magnitude in skeletal muscle fibers that is independent of UCP3, and a role for UCP3 in the control of pHlash frequency and of proton leak- and Complex I coupled-respiration in skeletal muscle fibers. The differential regulation of mitoflashes and pHlashes by UCP3 and tiron also indicate that the two events, though may be related, are not identical events.


Assuntos
Concentração de Íons de Hidrogênio , Mitocôndrias Musculares/metabolismo , Músculo Esquelético/metabolismo , Proteína Desacopladora 3/fisiologia , Animais , Metabolismo Energético , Potencial da Membrana Mitocondrial , Camundongos , Camundongos Endogâmicos C57BL , Consumo de Oxigênio , Proteína Desacopladora 3/genética
2.
Acta Paediatr ; 107(11): 1924-1931, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-29869345

RESUMO

AIM: To examine the sudden unexpected death in infancy (SUDI) disparity between Maori and non-Maori in New Zealand. METHODS: A nationwide prospective case-control study ran from March 2012 to February 2015. Exposure to established SUDI risk factors was analysed to investigate the disparity experienced by Maori. Infant ethnicity was based on mother's ethnicity. Maori ethnicity was prioritised. Non-Maori includes Pacific, Asian, NZ European and Other. RESULTS: There were 137 cases and 649 controls. The Maori SUDI rate was 1.41/1000 live births compared to 0.53/1000 for non-Maori. Parents/caregivers of 132 cases (96%) and 258 controls (40%) were interviewed. Smoking in pregnancy was associated with an equally increased SUDI risk for Maori (adjusted OR = 8.11, 95% CI = 2.64, 24.93) and non-Maori (aOR = 5.09, 95% CI = 1.79, 14.47), as was bed-sharing (aOR = 3.66, 95% CI = 1.49, 9.00 vs aOR = 11.20, 95% CI = 3.46, 36.29). Bed-sharing prevalence was similar; however, more Maori controls smoked during pregnancy (46.7%) than non-Maori (22.8%). The main contributor relating to increased SUDI risk for Maori/non-Maori infants is the combination of smoking in pregnancy and bed sharing. CONCLUSION: The association between known SUDI risk factors, including bed sharing and/or smoking in pregnancy and SUDI risk, is the same regardless of ethnicity. Maori infants are exposed more frequently to both behaviours because of the higher Maori smoking rate.


Assuntos
Havaiano Nativo ou Outro Ilhéu do Pacífico/estatística & dados numéricos , Fumar/efeitos adversos , Morte Súbita do Lactente/etnologia , Estudos de Casos e Controles , Feminino , Humanos , Lactente , Nova Zelândia/epidemiologia , Gravidez , Estudos Prospectivos , Fumar/epidemiologia , Morte Súbita do Lactente/etiologia
3.
Eur J Neurol ; 19(3): 462-7, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22329857

RESUMO

BACKGROUND AND PURPOSE: Niemann-Pick disease type C (NPC) is a progressive neurovisceral disorder associated with dystonia, ataxia and a characteristic gaze palsy. Neuropathological studies have demonstrated brainstem atrophy associated with neuronal inclusions and loss, and neurofibrillary tangles, although it is not known whether this pathology can be detected in vivo or how these changes relate to illness variables, particularly ocular-motor changes. Our aim was to utilize a method for brainstem atrophy, validated in progressive supranuclear palsy (PSP), in a group of adult patients with NPC, and explore its relationship to illness variables and ocular-motor functioning. METHODS: We calculated the midbrain and pontine area, and pontine-to-midbrain ratio (PMR) from midsagittal images of 10 adult patients with NPC and 27 age- and gender-matched controls. Measures were correlated with illness variables, and measures of horizontal saccadic functioning. RESULTS: Pontine-to-midbrain ratio was 14% higher in the NPC group, but this difference was not significant. However, PMR showed a significant positive correlation with duration of illness and a measure of illness severity. Furthermore, PMR was significantly negatively correlated with saccadic peak velocity and gain, and self-paced saccadic performance. CONCLUSIONS: Pontine-to-midbrain ratio was increased in adult patients with NPC compared to controls, although not to the same degree as previously described in PSP, which also presents with significant gaze palsy. These changes were driven predominantly by progressive midbrain atrophy. The strong correlation with illness and ocular-motor variables suggests that it may be a useful marker for illness progression in NPC.


Assuntos
Tronco Encefálico/patologia , Doença de Niemann-Pick Tipo C/patologia , Movimentos Sacádicos/fisiologia , Adolescente , Adulto , Tronco Encefálico/fisiopatologia , Progressão da Doença , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Doença de Niemann-Pick Tipo C/complicações , Doença de Niemann-Pick Tipo C/fisiopatologia , Adulto Jovem
4.
Euro Surveill ; 16(6)2011 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-21329643

RESUMO

This paper uses data from multiple surveillance systems to describe the experience in New Zealand with the second complete wave of pandemic influenza A(H1N1)2009 in 2010. Measures such as hospitalisation rates suggest the overall impact of influenza A(H1N1)2009 in 2010 was between half and two thirds that of the first wave in 2009. There was considerable regional and sub-regional variation with a tendency for higher activity in areas that experienced low rates in 2009. Demographic characteristics of the second wave were similar to those in 2009 with highest rates seen in children under the age of five years, and in indigenous Maori and Pacific peoples. Hospital services including intensive care units were not under as much pressure as in 2009. Immunisation appears to have contributed to the reduced impact of the pandemic in 2010, particularly for those aged 60 years and older.


Assuntos
Hospitalização/estatística & dados numéricos , Vírus da Influenza A Subtipo H1N1 , Influenza Humana/epidemiologia , Pandemias/estatística & dados numéricos , Distribuição por Idade , Notificação de Doenças , Feminino , Humanos , Imunização , Incidência , Vacinas contra Influenza , Influenza Humana/virologia , Unidades de Terapia Intensiva , Masculino , Nova Zelândia/epidemiologia , Vigilância da População , Estações do Ano , Distribuição por Sexo
5.
Inj Prev ; 16(1): 31-5, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20179033

RESUMO

BACKGROUND AND OBJECTIVE: Traumatic brain injury (TBI) is a frequently occurring event in childhood that may have significant ongoing effects. Little is known about the child and family characteristics that predispose children to these injuries. A greater understanding of the risk factors associated with childhood TBI may provide an opportunity to prevent their occurrence. METHODS: Information provided by a large birth cohort study (n=1265) was used to determine the child and family risk factors of TBI in children aged 0-15 years (n=187). All information regarding child, family, and injury events were collected prospectively and unrelated to the injury event itself. Child variables included in the analysis were sex and the level of behavioural problems. Parental variables included were family socioeconomic status, mother's age, education level, depressive symptoms, number of adverse life events experienced by the family, and parenting style. RESULTS: The most important risk factors were sex, adverse life events, and parenting style. The results suggest evidence of modest increases in the rate of TBI for those in the highest risk categories (male, >or=4 life events per annum, high maternal punitiveness) compared to the lowest risk categories, with hazard ratios in the region of 1.4-1.6. CONCLUSIONS: Overall characteristics of both the family and child predicted a TBI event. An increased understanding of risks associated with TBI in childhood will provide an avenue to prevent these injuries by targeting at-risk families and aiding the development of appropriate intervention strategies.


Assuntos
Lesões Encefálicas/etiologia , Adolescente , Adulto , Lesões Encefálicas/epidemiologia , Lesões Encefálicas/prevenção & controle , Criança , Transtornos do Comportamento Infantil/complicações , Transtornos do Comportamento Infantil/epidemiologia , Filho de Pais com Deficiência , Pré-Escolar , Depressão/epidemiologia , Métodos Epidemiológicos , Características da Família , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Idade Materna , Nova Zelândia/epidemiologia , Poder Familiar , Fatores Sexuais , Fatores Socioeconômicos , Adulto Jovem
6.
Child Care Health Dev ; 36(1): 22-30, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19250251

RESUMO

Abstract Background Mild traumatic brain injury (MTBI) is a leading cause of injury for children during their pre-school years. However, there is little information regarding the long-term outcomes of these injuries. Method We used fully prospective data from an epidemiological study of a birth cohort to examine behavioural effects associated with MTBI during the pre-school years. Cases of confirmed MTBI were divided into two groups, those that had received outpatient medical attention, and those that had been admitted to hospital for a brief period of observation (inpatient cases). The remainder of the cohort served as a reference control group. Results Mother/teacher ratings for behaviours associated with attention deficit/hyperactivity disorder and oppositional defiant/conduct disorder, obtained yearly from age 7 to 13, revealed evidence of deficits after inpatient MTBI (n = 21), relative to more minor outpatient injury MTBI (n = 55) and the reference control group (n = 852). For the inpatient group there was evidence of increasing deficits over years 7-13. Conclusions More severe pre-school MTBI may be associated with persistent negative effects in terms of psychosocial development. The vulnerability of pre-school children to MTBI signals a pressing need to identify high-risk cases that may benefit from monitoring and early intervention.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/etiologia , Lesões Encefálicas/complicações , Transtorno da Conduta/etiologia , Transtorno do Deficit de Atenção com Hiperatividade/epidemiologia , Lesões Encefálicas/diagnóstico , Pré-Escolar , Transtorno da Conduta/epidemiologia , Feminino , Humanos , Lactente , Estudos Longitudinais , Masculino , Avaliação de Resultados em Cuidados de Saúde , Inquéritos e Questionários
7.
J Cell Biol ; 153(1): 221-8, 2001 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-11285287

RESUMO

Smac/DIABLO, a recently identified inhibitor of apoptosis protein (IAP)-binding protein, is released from the mitochondria during apoptosis and reportedly potentiates apoptosis by relieving the inhibition of IAPs on caspases. We now describe the molecular characterization of Smac beta, an alternatively spliced form of Smac, which lacks the mitochondrial-targeting sequence found in Smac and has a cortical distribution in both human embryonic kidney 293 and breast epithelial tumor MCF-7 cells. Smac beta, which binds IAPs in vitro, does not bind IAPs in intact cells due to cellular processing and removal of its NH(2)-terminal IAP-binding domain. Despite its inability to interact with IAPs in cells, processed Smac beta is proapoptotic, as demonstrated by its ability to potentiate apoptosis induced by both death receptor and chemical stimuli. Furthermore, expression of a NH(2)-terminally truncated Smac mutant (Delta75), which lacks the entire IAP-interacting domain, potentiates apoptosis to the same extent as Smac and Smac beta. Our data support the hypothesis that the main proapoptotic function of Smac and Smac beta is due to a mechanism other than IAP binding.


Assuntos
Apoptose , Proteínas de Bactérias/metabolismo , Proteínas de Transporte/metabolismo , Proteínas de Insetos , Proteínas Mitocondriais , Sequência de Aminoácidos , Proteínas Reguladoras de Apoptose , Sítios de Ligação , Proteínas de Transporte/genética , Linhagem Celular , Humanos , Proteínas Inibidoras de Apoptose , Peptídeos e Proteínas de Sinalização Intracelular , Dados de Sequência Molecular , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteínas/metabolismo , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X
8.
J Cell Biol ; 148(6): 1239-54, 2000 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-10725337

RESUMO

Tumor necrosis factor-related apoptosis- inducing ligand (TRAIL) -induced apoptosis, in transformed human breast epithelial MCF-7 cells, resulted in a time-dependent activation of the initiator caspases-8 and -9 and the effector caspase-7. Cleavage of caspase-8 and its preferred substrate, Bid, preceded processing of caspases-7 and -9, indicating that caspase-8 is the apical initiator caspase in TRAIL-induced apoptosis. Using transient transfection of COOH-terminal-tagged green fluorescent protein fusion constructs, caspases-3, -7, and -8 were localized throughout the cytoplasm of MCF-7 cells. TRAIL-induced apoptosis resulted in activation of caspases-3 and -7, and the redistribution of most of their detectable catalytically active small subunits into large spheroidal cytoplasmic inclusions, which lacked a limiting membrane. These inclusions, which were also induced in untransfected cells, contained cytokeratins 8, 18, and 19, together with both a phosphorylated form and a caspase-cleavage fragment of cytokeratin 18. Similarly, in untransfected breast HBL100 and lung A549 epithelial cells, TRAIL induced the formation of cytoplasmic inclusions that contained cleaved cytokeratin 18 and colocalized with active endogenous caspase-3. We propose that effector caspase-mediated cleavage of cytokeratins, resulting in disassembly of the cytoskeleton and formation of cytoplasmic inclusions, may be a characteristic feature of epithelial cell apoptosis.


Assuntos
Apoptose/fisiologia , Caspases/metabolismo , Células Epiteliais/fisiologia , Corpos de Inclusão/fisiologia , Queratinas/metabolismo , Glicoproteínas de Membrana/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Proteínas Reguladoras de Apoptose , Mama , Caspase 3 , Caspase 7 , Caspase 8 , Caspase 9 , Células Epiteliais/ultraestrutura , Feminino , Proteínas de Fluorescência Verde , Humanos , Proteínas Luminescentes/análise , Microscopia Eletrônica , Microscopia Imunoeletrônica , Proteínas Recombinantes de Fusão/metabolismo , Ligante Indutor de Apoptose Relacionado a TNF , Transfecção
9.
J Cell Biol ; 137(2): 469-79, 1997 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-9128256

RESUMO

Identification of the processing/activation of multiple interleukin-1beta converting enzyme (ICE)-like proteases and their target substrates in the intact cell is critical to our understanding of the apoptotic process. In this study we demonstrate processing/activation of at least four ICE-like proteases during the execution phase of apoptosis in human monocytic tumor THP.1 cells. Apoptosis was accompanied by processing of Ich-1, CPP32, and Mch3alpha to their catalytically active subunits, and lysates from these cells displayed a proteolytic activity with kinetics, characteristic of CPP32/Mch3alpha but not of ICE. Fluorescence-activated cell sorting was used to obtain pure populations of normal and apoptotic cells. In apoptotic cells, extensive cleavage of Ich-1, CPP32, and Mch3alpha. was observed together with proteolysis of the ICE-like protease substrates, poly (ADP-ribose) polymerase (PARP), the 70-kD protein component of U1 small nuclear ribonucleoprotein (U1-70K), and lamins A/B. In contrast, no cleavage of CPP32, Mch3alpha or the substrates was observed in normal cells. In cells exposed to an apoptotic stimulus, some processing of Ich-1 was detected in morphologically normal cells, suggesting that cleavage of Ich-1 may occur early in the apoptotic process. The ICE-like protease inhibitor, benzyloxycarbonyl-Val-Ala-Asp (OMe) fluoromethyl ketone (Z-VAD.FMK), inhibited apoptosis and cleavage of Ich-1, CPP32, Mch3alpha, Mch2alpha, PARP, U1-70K, and lamins. These results suggest that Z-VAD.FMK inhibits apoptosis by inhibiting a key effector protease upstream of Ich-1, CPP32, Mch3alpha, and Mch2alpha. Together these observations demonstrate that processing/activation of Ich-1, CPP32, Mch3alpha, and Mch2alpha accompanies the execution phase of apoptosis in THP.1 cells. This is the first demonstration of the activation of at least four ICE-like proteases in apoptotic cells, providing further evidence for a requirement for the activation of multiple ICE-like proteases during apoptosis.


Assuntos
Apoptose/fisiologia , Cisteína Endopeptidases/metabolismo , Monócitos/citologia , Apoptose/efeitos dos fármacos , Caspase 1 , Inibidores de Cisteína Proteinase/farmacologia , Ativação Enzimática , Humanos , Cinética , Laminas , Monócitos/enzimologia , Proteínas Nucleares/metabolismo , Poli(ADP-Ribose) Polimerases/metabolismo , Precursores de Proteínas/metabolismo , Ribonucleoproteína Nuclear Pequena U1/metabolismo , Células Tumorais Cultivadas
10.
Xenobiotica ; 39(8): 616-24, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19622004

RESUMO

Programmed cell death and its morphological manifestation termed apoptosis is a conserved pathway that appears to operate in all multicellular organisms. During embryonic development, cell death is essential for successful organogenesis, and apoptosis also operates in adult organisms to maintain normal cellular homeostasis. The removal of disordered cells by a controlled cellular mechanism is especially critical in long-lived mammals that must integrate multiple physiological as well as pathological death signals. Gain- and loss-of-function models of genes in the core apoptotic pathway suggest that perturbation of cellular homeostasis can be a primary pathogenic event that results in disease. Indeed, there is now compelling evidence that insufficient apoptosis can manifest as cancer or autoimmunity, whereas accelerated cell death is evident in acute and chronic degenerative diseases, further highlighting the fact that deregulation of cell death pathways has major health implications. Not surprisingly, during the past 25 years a huge endeavour aimed at unravelling this fundamental biological process has led to major advances in our understanding of cell death pathways. Therapeutic strategies to manipulate apoptosis have immense potential and this review highlights several potentially viable drug targets for modulating cell death that have been discovered from the elegant work of many scientists in elucidating the protein components and key regulators of apoptosis signalling pathways.


Assuntos
Apoptose/efeitos dos fármacos , Sistemas de Liberação de Medicamentos , Neoplasias/tratamento farmacológico , Transdução de Sinais/efeitos dos fármacos , Animais , Autoimunidade , Homeostase , Humanos , Neoplasias/metabolismo , Neoplasias/patologia , Organogênese
11.
J Clin Neurosci ; 16(5): 642-4, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19269825

RESUMO

Subdural haematomas (SDHs), and in particular chronic subdural haematomas (CSDHs), are commonly encountered in a neurosurgical practice. The aetiology, presentation, management and prognosis of these are well documented but there are few publications that report on their side prevalence (laterality). We report an analysis of all patients (both operated on and conservatively managed) who presented to the Neurosurgical Service at Christchurch Hospital with SDHs between 1 January 1996 and 30 June 2006. A total of 413 patients presented with a total of 450 SDHs, of which 150 (33.3%) were acute, 38 were (8.4%) subacute and 262 (58.2%) were chronic. The patients ranged in age from 3 months to 95 years. The mean (+/-standard deviation, SD) age of patients with acute SDH was 50.9+/-25.8 years, 65.4+/-19.8 years for subacute SDH and 68.9+/-19.7 years for chronic SDH. A total of 275 (67%) patients were male and 138 (33%) female, with the male predominance occurring in all subgroups. The SDHs were distributed unilaterally in the acute and subacute groups; however, CSDHs occurred more frequently on the left side (57.2% compared to 42.7% on the right; p=0.0345). We discuss the likely reasons behind the increased rate of CSDHs diagnoses on the left side.


Assuntos
Lateralidade Funcional/fisiologia , Hematoma Subdural Crônico/epidemiologia , Hematoma Subdural Crônico/fisiopatologia , Doença Aguda , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto Jovem
12.
Cell Death Differ ; 14(1): 137-45, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16645643

RESUMO

There is growing evidence that the insulin-like growth factor-binding protein 3 (IGFBP-3) can have IGF-independent effects on cell growth. However, despite the fact that IGFBP-3 has been reported to be both antiproliferative and proapoptotic, the molecular mechanisms underlying the action of IGFBP-3 have not been elucidated. We report that although addition of IGFBP-3 (either synthetic or secreted protein) had no effect on cell survival, IGFBP-3 (100 ng/ml) significantly enhanced TNF-related apoptosis-inducing ligand (TRAIL)-induced cell death in colonic carcinoma-derived cell lines (20-30% depending on cell line), whereas it had no effect on the survival of the TRAIL-resistant adenoma-derived cells. Both addition of IGFBP-3 protein to cell cultures or enforced expression of IGFBP-3 in the HT29 carcinoma cell line inhibited nuclear factor kappa B (NF-kappaB) activation in response to the induction of apoptosis by TRAIL. We propose that IGFBP-3 is a non-toxic NF-kappaB inhibitor, which could be used as an adjuvant in the treatment of colon cancer.


Assuntos
Adenoma/fisiopatologia , Apoptose , Carcinoma/fisiopatologia , Neoplasias Colorretais/fisiopatologia , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/metabolismo , NF-kappa B/metabolismo , Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Linhagem Celular Tumoral , Células HT29 , Humanos , Proteínas I-kappa B , Inibidor de NF-kappaB alfa , Transdução de Sinais , Células Tumorais Cultivadas
13.
J Hosp Infect ; 65(3): 231-6, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17178427

RESUMO

Methicillin-resistant Staphylococcus aureus (MRSA) is recognized as a bacterial pathogen in patients with cystic fibrosis (CF) although its clinical effects can be variable. The aim of this study was to evaluate the efficacy of a three-step decolonization protocol for MRSA (Belfast CF MRSA decolonization protocol). Of the 17 paediatric patients treated during the five years of the study, eight (47%) were successfully decolonized following one five-day course of oral rifampicin and fusidic acid. The success rate increased to 12 (71%) patients after a second five-day oral treatment course in the 11 patients who remained culture positive at the end of the first treatment cycle. In a further four patients, clearance was achieved with a course of intravenous teicoplanin, increasing the decolonization rate to 16 of 17 patients (94%). These results compare favourably with other published studies and show that MRSA decolonization can be successful in a high proportion of paediatric CF patients.


Assuntos
Antibacterianos/uso terapêutico , Fibrose Cística/microbiologia , Resistência a Meticilina/efeitos dos fármacos , Pneumonia/tratamento farmacológico , Escarro/microbiologia , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/efeitos dos fármacos , Adolescente , Criança , Pré-Escolar , Fibrose Cística/complicações , Quimioterapia Combinada , Feminino , Ácido Fusídico/uso terapêutico , Humanos , Lactente , Masculino , Rifampina/uso terapêutico , Índice de Gravidade de Doença , Infecções Estafilocócicas/prevenção & controle , Teicoplanina/uso terapêutico
14.
Mol Cell Biol ; 20(4): 1162-9, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10648601

RESUMO

Recent studies have shown that during apoptosis protein synthesis is inhibited and that this is in part due to the proteolytic cleavage of eukaryotic initiation factor 4G (eIF4G). Initiation of translation can occur either by a cap-dependent mechanism or by internal ribosome entry. The latter mechanism is dependent on a complex structural element located in the 5' untranslated region of the mRNA which is termed an internal ribosome entry segment (IRES). In general, IRES-mediated translation does not require eIF4E or full-length eIF4G. In order to investigate whether cap-dependent and cap-independent translation are reduced during apoptosis, we examined the expression of c-Myc during this process, since we have shown previously that the 5' untranslated region of the c-myc proto-oncogene contains an IRES. c-Myc expression was determined in HeLa cells during apoptosis induced by tumor necrosis factor-related apoptosis-inducing ligand. We have demonstrated that the c-Myc protein is still expressed when more than 90% of the cells are apoptotic. The presence of the protein in apoptotic cells does not result from either an increase in protein stability or an increase in expression of c-myc mRNA. Furthermore, we show that during apoptosis initiation of c-myc translation occurs by internal ribosome entry. We have investigated the signaling pathways that are involved in this response, and cotransfection with plasmids which harbor either wild-type or constitutively active MKK6, a specific immediate upstream activator of p38 mitogen-activated protein kinase (MAPK), increases IRES-mediated translation. In addition, the c-myc IRES is inhibited by SB203580, a specific inhibitor of p38 MAPK. Our data, therefore, strongly suggest that the initiation of translation via the c-myc IRES during apoptosis is mediated by the p38 MAPK pathway.


Assuntos
Apoptose/fisiologia , Proteínas Proto-Oncogênicas c-myc/biossíntese , Ribossomos/metabolismo , Apoptose/efeitos dos fármacos , Apoptose/genética , Proteínas Reguladoras de Apoptose , Genes myc , Meia-Vida , Células HeLa , Humanos , Glicoproteínas de Membrana/farmacologia , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Inibidores da Síntese de Proteínas/farmacologia , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas c-myc/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Estaurosporina/farmacologia , Ligante Indutor de Apoptose Relacionado a TNF , Fator de Necrose Tumoral alfa/farmacologia
15.
Cell Death Differ ; 12(7): 773-82, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15861184

RESUMO

Clinical trials have been initiated with Apo2L/TRAIL (Genentech) and agonistic mAbs to TRAIL receptors, -R1 and -R2 (Human Genome Sciences). The apoptosis-inducing ability of these mAbs and different TRAIL preparations, in the presence or absence of histone deacetylase inhibitors (HDACi), varied markedly against primary chronic lymphocytic leukaemia (CLL) cells and various tumor cell lines, demonstrating an unanticipated preferential apoptotic signaling via either TRAIL-R1 or -R2. Contrary to literature reports that TRAIL-induced apoptosis occurs primarily via signaling through TRAIL-R2, CLL cells, in the presence of HDACi, undergo predominantly TRAIL-R1-mediated apoptosis. Consequently, Apo2L/TRAIL, which signals primarily through TRAIL-R2, is virtually devoid of activity against CLL cells. To maximize therapeutic benefit, it is essential to ascertain whether a primary tumor signals via TRAIL-R1/-R2, prior to initiating therapy. Thus combination of an agonistic TRAIL-R1 Ab and an HDACi, such as the anticonvulsant sodium valproate, could be of value in treating CLL.


Assuntos
Apoptose , Leucemia Linfocítica Crônica de Células B/metabolismo , Leucemia Linfocítica Crônica de Células B/patologia , Glicoproteínas de Membrana/metabolismo , Transdução de Sinais , Fator de Necrose Tumoral alfa/metabolismo , Adulto , Idoso , Apoptose/efeitos dos fármacos , Proteínas Reguladoras de Apoptose , Depsipeptídeos/farmacologia , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Histona Desacetilases/metabolismo , Humanos , Células K562 , Masculino , Glicoproteínas de Membrana/antagonistas & inibidores , Pessoa de Meia-Idade , Receptores de Superfície Celular/genética , Receptores do Ligante Indutor de Apoptose Relacionado a TNF , Receptores do Fator de Necrose Tumoral/metabolismo , Transdução de Sinais/efeitos dos fármacos , Ligante Indutor de Apoptose Relacionado a TNF , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Proteína Supressora de Tumor p53/metabolismo , Células U937
16.
J Small Anim Pract ; 57(2): 84-90, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26577242

RESUMO

OBJECTIVES: The aim of this retrospective study was to review placement duration and associated complications of long-stay, peripheral venous cannulae in dogs undergoing a radiotherapy protocol. Factors affecting duration of stay of the cannulae were evaluated. METHODS: The records of patients which had a single-lumen, 16-gauge, 16-cm polyurethane cannulae inserted into a peripheral vein between 2010 and 2014 were reviewed. RESULTS: Forty-one cannulae were placed in 41 patients. Median duration of cannula stay was 14 days (range 2 to 26). In 14 cases (~34%) the cannula was removed at the end of the radiotherapy course. In 13 (~32%) cases, cannula-related complications resulted in premature removal. Use of steroids and antibiotics appeared to be associated with a longer median duration of stay. CLINICAL SIGNIFICANCE: No life-threatening complications were encountered. Indwelling, polyurethane, saphenous cannulae were an effective and safe way to maintain venous access in this group of patients. Prednisolone and antibiotics were typically commenced for acute radiation side effects -midway through the protocol; therefore their association with length of stay may not be a direct result of their administration.


Assuntos
Cateterismo Periférico/veterinária , Poliuretanos , Radioterapia/veterinária , Animais , Materiais Biocompatíveis , Cânula/efeitos adversos , Cânula/veterinária , Cateterismo Periférico/efeitos adversos , Cães , Feminino , Masculino , Radioterapia/métodos , Estudos Retrospectivos , Fatores de Tempo
17.
Oncogene ; 35(43): 5629-5640, 2016 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-27109099

RESUMO

Caspase-8 is a key initiator of apoptotic cell death where it functions as the apical protease in death receptor-mediated apoptosis triggered via the death-inducing signalling complex (DISC). However, the observation that caspase-8 is upregulated in many common tumour types led to the discovery of alternative non-apoptotic, pro-survival functions, many of which are contingent on phosphorylation of a tyrosine residue (Y380) found in the linker region between the two catalytic domains of the enzyme. Furthermore, Src-mediated Y380 phosphorylation leads to increased resistance to CD95-induced apoptosis; however, the mechanism underlying this impaired response to extrinsic apoptotic stimuli has not been identified. Consequently, we have employed a number of model systems to further dissect this protective mechanism. First, using an in vitro DISC model together with recombinant procaspase-8 variants, we show that Y380 phosphorylation inhibits procaspase-8 activation at the CD95 DISC, thereby preventing downstream activation of the caspase cascade. Second, we validated this finding in a cellular context using transfected neuroblastoma cell lines deficient in caspase-8. Reconstitution of these lines with phosphomimetic-caspase-8 results in increased resistance to CD95-mediated apoptosis and enhanced cell migration. When the in vitro DISC is assembled in the presence of cell lysate, caspase-8 Y380 phosphorylation attenuates DISC activity by inhibiting procaspase-8 autoproteolytic activity but not recruitment or homodimerization of caspase-8 within the complex. Once incorporated into the DISC, phosphorylated caspase-8 is unable to be released from the complex; this inhibits further cycling and release of active catalytic subunits into the cytoplasm, thus resulting in increased apoptotic resistance. Taken together, our novel findings expand our understanding of the key mechanisms underlying the anti-apoptotic functions of caspase-8 which may act as a critical block to existing antitumour therapies. Importantly, reversal or inhibition of caspase-8 phosphorylation may prove a valuable avenue to explore for sensitization of resistant tumours to extrinsic apoptotic stimuli.


Assuntos
Caspase 8/metabolismo , Proteínas Adaptadoras de Sinalização de Receptores de Domínio de Morte/metabolismo , Tirosina/metabolismo , Receptor fas/metabolismo , Apoptose , Caspase 8/química , Caspase 8/genética , Linhagem Celular Tumoral , Ativação Enzimática , Humanos , Células Jurkat , Modelos Biológicos , Modelos Moleculares , Mutação , Fosforilação , Conformação Proteica , Multimerização Proteica , Proteólise , Transdução de Sinais , Quinases da Família src
18.
J Small Anim Pract ; 57(3): 135-41, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26712718

RESUMO

OBJECTIVE: To investigate the ability of neutrophil-to-lymphocyte ratio and albumin-to-globulin ratio to differentiate soft tissue sarcoma from benign soft tissue tumours. METHODS: A retrospective study of pretreatment haematology and biochemistry in dogs diagnosed with soft tissue sarcoma or benign soft tissue tumours. The neutrophil-to-lymphocyte ratio and albumin-to-globulin ratio were compared between the two groups. In dogs diagnosed with soft tissue sarcoma, the relationship of neutrophil-to-lymphocyte ratio and albumin-to-globulin ratio to histological tumour grade (I to III) was assessed. RESULTS: In the dogs with soft tissue sarcoma (n=22), the neutrophil-to-lymphocyte ratio was significantly increased and the albumin-to-globulin ratio decreased compared to those with benign soft tissue tumours (n=14). The neutrophil-to-lymphocyte ratio and albumin-to globulin ratio were not useful as predictors of tumour grade in dogs diagnosed with soft tissue sarcoma. CLINICAL SIGNIFICANCE: Pretreatment neutrophil-to-lymphocyte ratio and albumin-to globulin ratio may aid with diagnosis and optimal treatment planning. Further investigation into their prognostic implications is warranted.


Assuntos
Linfócitos , Neutrófilos , Sarcoma/veterinária , Albuminas/análise , Animais , Contagem de Células Sanguíneas/veterinária , Cães , Feminino , Globulinas/análise , Contagem de Linfócitos/veterinária , Masculino , Sarcoma/diagnóstico
19.
Pediatr Pulmonol ; 51(4): 379-85, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26808981

RESUMO

BACKGROUND: RSV causes considerable morbidity and mortality in children. In cystic fibrosis (CF) viral infections are associated with worsening respiratory symptoms and bacterial colonization. Palivizumab is effective in reducing RSV hospitalization in high risk patient groups. Evidence regarding its effectiveness and safety in CF is inconclusive. CF screening in N. Ireland enabled timely palivizumab prophylaxis, becoming routine in 2002. OBJECTIVES: To determine the effect of palivizumab on RSV-related hospitalization and compare lung function and bacterial colonization at age 6 years for those born pre- and post-introduction of palivizumab prophylaxis. METHODS: A retrospective audit was conducted for all patients diagnosed with CF during the period from 1997 to 2007 inclusive. RSV-related hospitalization, time to Pseudomonas aeruginosa (PA) 1st isolate, lung function and growth parameters were recorded. Comparisons were made for outcomes pre- and post-introduction of routine palivizumab administration in 2002. A cost evaluation was also performed. RESULTS: Ninety-two children were included; 47 pre- and 45 post-palivizumab introduction. The overall RSV-positive hospitalization rate was 13%. The relative risk of RSV infection in palivizumab non-recipients versus recipients was 4.78 (95%CI: 1.1-20.7), P = 0.027. Notably, PA 1st isolate was significantly earlier in the palivizumab recipient cohort versus non-recipient cohort (median 57 vs. 96 months, P < 0.025) with a relative risk of 2.5. Chronic PA infection at 6 years remained low in both groups, with similar lung function and growth parameters. Total costs were calculated at £96,127 ($151,880) for the non-recipient cohort versus £137,954 ($217,967) for the recipient cohort. CONCLUSION: Palivizumab was effective in reducing RSV-related hospitalization infection in CF patients. Surprisingly, we found a significantly earlier time to 1st isolate of PA in palivizumab recipients which we could not explain by altered or improved diagnostic tests.


Assuntos
Antivirais/uso terapêutico , Fibrose Cística/complicações , Palivizumab/uso terapêutico , Infecções por Vírus Respiratório Sincicial/prevenção & controle , Análise Custo-Benefício , Fibrose Cística/fisiopatologia , Feminino , Hospitalização , Humanos , Lactente , Masculino , Irlanda do Norte/epidemiologia , Infecções por Pseudomonas/prevenção & controle , Pseudomonas aeruginosa/isolamento & purificação , Infecções por Vírus Respiratório Sincicial/tratamento farmacológico , Infecções por Vírus Respiratório Sincicial/etiologia , Estudos Retrospectivos , Resultado do Tratamento
20.
Vet Rec ; 179(19): 491, 2016 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-27650464

RESUMO

Canine mast cell tumours (MCTs) are variable in their biological behaviour and treatment decisions depend heavily on the histopathological grade. Biomarkers such as neutrophil to lymphocyte ratio (NLR) and albumin to globulin ratio are used to predict the biological behaviour of human neoplasms, but have not been widely studied in dogs. A retrospective analysis identified 62 cases of gross MCT (14 high-grade, 48 low-grade tumours). Median NLR was significantly different between high- and low-grade MCT and tumours at different locations. A multivariable model identified increasing NLR (OR 2.0) and age (OR 1.7) to be associated with an increased risk of high-grade MCT. Receiver operating characteristic curve analysis identified an NLR threshold value of 5.67 (sensitivity 85.7 per cent; specificity 54.2 per cent) for predicting a high-grade MCT. An NLR threshold of 5.67 could be useful alongside existing tools (appearance, location, etc.) to help to predict the grade of MCT. With further validation, this biomarker could be used to guide clinical decisions before obtaining a histopathological diagnosis.


Assuntos
Doenças do Cão/patologia , Mastocitose Cutânea/patologia , Mastocitose Cutânea/veterinária , Animais , Biomarcadores Tumorais , Cães , Feminino , Contagem de Leucócitos , Contagem de Linfócitos , Masculino , Gradação de Tumores , Neutrófilos , Estudos Retrospectivos , Sensibilidade e Especificidade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA