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2.
BMJ Case Rep ; 14(9)2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34493552

RESUMO

This case report highlights the potentially serious side effects of hyoscine and how a seemingly innocuous patch may confound patients and doctors alike. It demonstrates how easy it is to miss an obvious diagnosis when in fact a thorough medical history including an exhaustive drug history can easily point us in the direction of the diagnosis fairly quickly. Finally, hyoscine may cause potentially serious side effects and patients who are taking it, either orally or transdermally, should be made aware of these.


Assuntos
Escopolamina , Choque , Humanos
3.
Int J Infect Dis ; 111: 333-335, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34403784

RESUMO

This single-centre observational study demonstrated that lower cycle threshold (Ct) values (indicating higher viral loads) on admission to hospital were associated with poorer outcomes in unvaccinated, hospitalized patients with coronavirus disease 2019 (COVID-19). Demographic and outcome data were collected prospectively for all adult patients who tested positive for severe acute respiratory syndrome coronavirus-2 on admission to the University Hospitals North Midlands NHS Trust between 1 February and 1 July 2020. Nasopharyngeal swab samples were obtained, and a valid Ct value was determined for all patients using the Viasure reverse transcription polymerase chain reaction assay, validated by Public Health England, on admission to hospital. Multi-variable logistic regression results based on data from 618 individuals demonstrated a significant inverse relationship between the odds of death and Ct values (adjusted odds ratio 0.95, 95% confidence interval 0.92-0.98, P=0.001). The association remained highly significant after adjusting for known clinical risk factors for COVID-19.


Assuntos
COVID-19 , Adulto , Humanos , Estudos Prospectivos , SARS-CoV-2 , Centros de Atenção Terciária , Reino Unido
4.
Ther Adv Infect Dis ; 8: 2049936121998548, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33796289

RESUMO

BACKGROUND: Cleaning is a major control component for outbreaks of infection. However, for the SARS-CoV-2 pandemic, there is limited specific guidance regarding the proper disinfection methods that should be used. METHODS: We conducted a systematic review of the literature on cleaning, disinfection or decontamination methods in the prevention of SARS-CoV-2. RESULTS: A total of 27 studies were included, reporting a variety of methods with which the effectiveness of interventions were assessed. Virus was inoculated onto different types of material including masks, nasopharyngeal swabs, serum, laboratory plates and simulated saliva, tears or nasal fluid and then interventions were applied in an attempt to eliminate the virus including chemical, ultraviolet (UV) light irradiation, and heat and humidity. At body temperature (37°C) there is evidence that the virus will not be detectable after 2 days but this can be reduced to non-detection at 30 min at 56°C, 15 min at 65°C and 2 min at 98°C. Different experimental methods testing UV light have shown that it can inactivate the virus. Light of 254-365 nm has been used, including simulated sunlight. Many chemical agents including bleach, hand sanitiser, hand wash, soap, ethanol, isopropanol, guandinium thiocynate/t-octylphenoxypolyethoxyethanol, formaldehyde, povidone-iodine, 0.05% chlorhexidine, 0.1% benzalkonium chloride, acidic electrolysed water, Clyraguard copper iodine complex and hydrogen peroxide vapour have been shown to disinfect SARS-CoV-2. CONCLUSIONS: Heating, UV light irradiation and chemicals can be used to inactivate SARS-CoV-2 but there is insufficient evidence to support one measure over others in clinical practice.

5.
Br J Cardiol ; 28(3): 38, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35747699

RESUMO

In a cardiology department, there are some patients that require long-term antibiotics, such as those with infective endocarditis or infected prosthetic devices. We describe our experience with intravenous antibiotic therapy for patients with cardiology diagnoses who require a period of antibiotics in our outpatient service during the period of the COVID-19 pandemic. A total of 15 patients were selected to have outpatient antibiotic therapy (age range 36 to 97 years, 60% male). A total of nine patients had infective endocarditis, four patients had infected valve prosthesis or transcatheter aortic valve implantation (TAVI) endocarditis, one patient had infected pericardial effusion while another had infected pericarditis. For these 15 patients there was a total of 333 hospital bed-days, on average 22 days per patient. These patients also had a total of 312 days of outpatient antibiotic therapy, which was an average of 21 days per patient. The total cost, if patients were admitted for those days, assuming a night cost £400, was £124,800, which was on average £8,320 per patient. Three patients were readmitted within 30 days. One had ongoing endocarditis that was managed medically and another had pulmonary embolism. The last patient had a side effect related to daptomycin use. In conclusion, outpatient antibiotic therapy in selected patients with native or prosthetic infective endocarditis appears to be safe for a selected group of patients with associated cost savings.

6.
Clin Infect Pract ; 10: 100042, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32999997

RESUMO

BACKGROUND: Covid-19 is a novel disease caused by the severe acute respiratory coronavirus (SARS-CoV2). We discuss a gentleman who presented with an atraumatic rupture of the spleen secondary to this infection. BRIEF SUMMARY OF PRESENTATION: A 57-year-old service engineer was brought into the emergency department after having collapsed at home. RT-PCR was positive for covid-19 infection. CT scan showed evidence of haemoperitoneum and splenic rupture. He underwent splenic artery embolisation and required ventilatory and circulatory support on ITU. He made a full recovery and was discharged home 3 weeks later. DISCUSSION AND RELEVANCE: Atraumatic splenic rupture is a rare, potentially fatal condition which has been described as a complication of haematological and non-haematological malignancies, inflammatory disorders and infections. There is emerging evidence to suggest that covid-19 has a direct destructive impact on the spleen, causing lymphoid follicle attrition and nodular atrophy in addition to microvascular thrombosis and necrosis. This is the first report of atraumatic splenic rupture secondary to covid-19 infection, to our knowledge.

7.
Bioeng Transl Med ; 3(1): 58-70, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29376134

RESUMO

The ability to perform laboratory testing near the patient and with smaller blood volumes would benefit patients and physicians alike. We describe our design of a miniaturized clinical laboratory system with three components: a hardware platform (ie, the miniLab) that performs preanalytical and analytical processing steps using miniaturized sample manipulation and detection modules, an assay-configurable cartridge that provides consumable materials and assay reagents, and a server that communicates bidirectionally with the miniLab to manage assay-specific protocols and analyze, store, and report results (i.e., the virtual analyzer). The miniLab can detect analytes in blood using multiple methods, including molecular diagnostics, immunoassays, clinical chemistry, and hematology. Analytical performance results show that our qualitative Zika virus assay has a limit of detection of 55 genomic copies/ml. For our anti-herpes simplex virus type 2 immunoglobulin G, lipid panel, and lymphocyte subset panel assays, the miniLab has low imprecision, and method comparison results agree well with those from the United States Food and Drug Administration-cleared devices. With its small footprint and versatility, the miniLab has the potential to provide testing of a range of analytes in decentralized locations.

8.
Dent Update ; 40(8): 679-80, 682, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24279220

RESUMO

UNLABELLED: Appraisal has been a key component of staff management of most organizations for more than a decade. This article explores the principles, benefits and stages for effective appraisal in primary dental care. CLINICAL RELEVANCE: Reviewing what works and what does not and reflection on these points are key to developing professional skills. Appraisal is a formalized way of reflecting on the past to help a professional plan for his/her future and thereby, ideally, improve patient care.


Assuntos
Competência Clínica/normas , Odontólogos/normas , Educação Continuada em Odontologia/normas , Odontologia Geral/educação , Conscientização , Tomada de Decisões , Odontologia Geral/normas , Objetivos , Humanos , Aprendizagem , Autoimagem , Desenvolvimento de Pessoal/normas , Reino Unido
9.
Eur J Heart Fail ; 10(12): 1177-80, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18974021

RESUMO

A greater understanding of the molecular basis of hibernating myocardium may assist in identifying those patients who would most benefit from revascularization. Paired heart biopsies were taken from hypocontractile and normally-contracting myocardium (identified by cardiovascular magnetic resonance) from 6 patients with chronic stable angina scheduled for bypass grafting. Gene expression profiles of hypocontractile and normally-contracting samples were compared using Affymetrix microarrays. The data for patients with confirmed hibernating myocardium were analysed separately and a different, though overlapping, set (up to 380) of genes was identified which may constitute a molecular fingerprint for hibernating myocardium. The expression of B-type natriuretic peptide (BNP) was increased in hypocontractile relative to normally-contracting myocardium. The expression of BNP correlated most closely with the expression of proenkephalin and follistatin 3, which may constitute additional heart failure markers. Our data illustrate differential gene expression in hypocontractile and/hibernating myocardium relative to normally-contracting myocardium within individual human hearts. Changes in expression of these genes, including increased relative expression of natriuretic and other factors, may constitute a molecular signature for hypocontractile and/or hibernating myocardium.


Assuntos
Fator Natriurético Atrial/biossíntese , Encefalinas/biossíntese , Proteínas Relacionadas à Folistatina/biossíntese , Perfilação da Expressão Gênica , Contração Miocárdica , Miocárdio/metabolismo , Peptídeo Natriurético Encefálico/biossíntese , Precursores de Proteínas/biossíntese , Angina Pectoris/fisiopatologia , Fator Natriurético Atrial/genética , Encefalinas/genética , Proteínas Relacionadas à Folistatina/genética , Humanos , Peptídeo Natriurético Encefálico/genética , Precursores de Proteínas/genética , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Função Ventricular Esquerda
10.
Genome Biol ; 9(2): R32, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18275597

RESUMO

BACKGROUND: Endothelin-1 stimulates Gq protein-coupled receptors to promote proliferation in dividing cells or hypertrophy in terminally differentiated cardiomyocytes. In cardiomyocytes, endothelin-1 rapidly (within minutes) stimulates protein kinase signaling, including extracellular-signal regulated kinases 1/2 (ERK1/2; though not ERK5), with phenotypic/physiological changes developing from approximately 12 h. Hypertrophy is associated with changes in mRNA/protein expression, presumably consequent to protein kinase signaling, but the connections between early, transient signaling events and developed hypertrophy are unknown. RESULTS: Using microarrays, we defined the early transcriptional responses of neonatal rat cardiomyocytes to endothelin-1 over 4 h, differentiating between immediate early gene (IEG) and second phase RNAs with cycloheximide. IEGs exhibited differential temporal and transient regulation, with expression of second phase RNAs within 1 h. Of transcripts upregulated at 30 minutes encoding established proteins, 28 were inhibited >50% by U0126 (which inhibits ERK1/2/5 signaling), with 9 inhibited 25-50%. Expression of only four transcripts was not inhibited. At 1 h, most RNAs (approximately 67%) were equally changed in total and polysomal RNA with approximately 17% of transcripts increased to a greater extent in polysomes. Thus, changes in expression of most protein-coding RNAs should be reflected in protein synthesis. However, approximately 16% of transcripts were essentially excluded from the polysomes, including some protein-coding mRNAs, presumably inefficiently translated. CONCLUSION: The phasic, temporal regulation of early transcriptional responses induced by endothelin-1 in cardiomyocytes indicates that, even in terminally differentiated cells, signals are propagated beyond the primary signaling pathways through transcriptional networks leading to phenotypic changes (that is, hypertrophy). Furthermore, ERK1/2 signaling plays a major role in this response.


Assuntos
Endotelina-1/fisiologia , Regulação da Expressão Gênica , Miócitos Cardíacos/metabolismo , Animais , Células Cultivadas , Endotelina-1/farmacologia , Perfilação da Expressão Gênica , Proteína Quinase 1 Ativada por Mitógeno/genética , Proteína Quinase 3 Ativada por Mitógeno/genética , Miócitos Cardíacos/efeitos dos fármacos , Análise de Sequência com Séries de Oligonucleotídeos , Biossíntese de Proteínas/efeitos dos fármacos , Biossíntese de Proteínas/genética , RNA Mensageiro/análise , RNA Mensageiro/metabolismo , Ratos , Transdução de Sinais , Transcrição Gênica
11.
Physiol Genomics ; 29(2): 118-27, 2007 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-17148688

RESUMO

High levels of oxidative stress promote cardiac myocyte death, though lower levels are potentially cytoprotective/anabolic. We examined the changes in gene expression in rat neonatal cardiac myocytes exposed to apoptotic (0.2 mM) or nontoxic (0.04 mM) concentrations of H2O2 (2, 4, or 24 h) using Affymetrix microarrays. Using U34B arrays, we identified a ubiquitously expressed, novel H2O2-responsive gene [putative peroxide-inducible transcript 1 (Perit1)], which generates two alternatively spliced transcripts. Using 230 2.0 arrays, H2O2 (0.04 mM) promoted significant changes in expression of only 32 genes, all of which were seen with 0.2 mM H2O2. We failed to detect any increase in the rate of protein synthesis in cardiac myocytes exposed to <0.1 mM H2O2, further suggesting that global, low concentrations of H2O2 are not anabolic in this system. H2O2 (0.2 mM) promoted significant (P < 0.05, >1.75-fold) changes in expression of 649 mRNAs and 187 RNAs corresponding to no established gene. Of the mRNAs, 114 encoded transcriptional regulators including Krüppel-like factors (Klfs). Quantitative PCR independently verified the changes in Klf expression. Thus, H2O2-induced cardiac myocyte apoptosis is associated with dynamic changes in gene expression. The expression of these genes and their protein products potentially influences the progression of the apoptotic response.


Assuntos
Apoptose/fisiologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Peróxido de Hidrogênio/toxicidade , Miócitos Cardíacos/metabolismo , Estresse Oxidativo/fisiologia , Proteínas/genética , Animais , Apoptose/efeitos dos fármacos , Northern Blotting , Biologia Computacional , Primers do DNA , Etiquetas de Sequências Expressas , Análise em Microsséries , Miócitos Cardíacos/efeitos dos fármacos , Proteínas/metabolismo , Ratos , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/efeitos dos fármacos
12.
J Mol Cell Cardiol ; 41(2): 236-47, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16756989

RESUMO

The hypertrophic agonist endothelin-1 rapidly but transiently activates the extracellular signal-regulated kinase 1/2 (ERK1/2) cascade (and other signalling pathways) in cardiac myocytes, but the events linking this to hypertrophy are not understood. Using Affymetrix rat U34A microarrays, we identified the short-term (2-4 h) changes in gene expression induced in neonatal myocytes by endothelin-1 alone or in combination with the ERK1/2 cascade inhibitor, U0126. Expression of 15 genes was significantly changed by U0126 alone, and expression of an additional 78 genes was significantly changed by endothelin-1. Of the genes upregulated by U0126, four are classically induced through the aryl hydrocarbon receptor (AhR) by dioxins suggesting that U0126 activates the xenobiotic response element in cardiac myocytes potentially independently of effects on ERK1/2 signalling. The 78 genes showing altered expression with endothelin-1 formed five clusters: (i) three clusters showing upregulation by endothelin-1 according to time course (4 h > 2 h; 2 h > 4 h; 2 h approximately 4 h) with at least partial inhibition by U0126; (ii) a cluster of 11 genes upregulated by endothelin-1 but unaffected by U0126 suggesting regulation through signalling pathways other than ERK1/2; (iii) a cluster of six genes downregulated by endothelin-1 with attenuation by U0126. Thus, U0126 apparently activates the AhR in cardiac myocytes (which must be taken into account in protracted studies), but careful analysis allows identification of genes potentially regulated acutely via the ERK1/2 cascade. Our data suggest that the majority of changes in gene expression induced by endothelin-1 are mediated by the ERK1/2 cascade.


Assuntos
Butadienos/farmacologia , Endotelina-1/farmacologia , Inibidores Enzimáticos/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Miócitos Cardíacos/fisiologia , Nitrilas/farmacologia , Animais , Animais Recém-Nascidos , Células Cultivadas , Perfilação da Expressão Gênica , Regulação da Expressão Gênica/fisiologia , Ventrículos do Coração/citologia , Sistema de Sinalização das MAP Quinases/fisiologia , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Miócitos Cardíacos/citologia , Análise de Sequência com Séries de Oligonucleotídeos , Ratos , Ratos Sprague-Dawley , Fatores de Tempo , Função Ventricular
13.
Adv Enzyme Regul ; 45: 94-111, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16084574

RESUMO

Considerable efforts have been expended in elucidating the inter-cellular and intra-cellular signaling pathways which elicit cardiac myocyte hypertrophy or apoptosis, and in identifying the changes which are associated with the end-stage of the response. The challenge now is to link the two. Although some of the signaling effects will be the acute modulation of existing protein function, long-term effects which bring about and maintain the hypertrophic state or which culminate in cell death are mediated at the level of gene and protein expression. With the advances in micro-array technology and genome sequencing, it is now possible to obtain a picture of the global gene expression profile in myocytes or in whole heart which dictates the proteins which could be made. This is not the final picture since additional regulation at the level of translation modulates the relative proportions of each protein that can be made from the transcriptome. Even here, further regulation of protein stability and turnover means that ultimately it is still necessary to examine the proteome to determine what may cause the functional changes in a cell. Thus, in order to gain a full picture of events which regulate the response and gain some insight into possible points of intervention for therapy, it is necessary to examine gene expression, mRNA translation and protein expression in concert.


Assuntos
Apoptose/fisiologia , Regulação da Expressão Gênica/fisiologia , Hipertrofia/fisiopatologia , Miócitos Cardíacos/fisiologia , Animais , Proteínas de Choque Térmico/biossíntese , Sistema de Sinalização das MAP Quinases/fisiologia , Peroxidases/biossíntese , Peroxirredoxinas , Proteômica , Ratos , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase Via Transcriptase Reversa
14.
Acta Paediatr ; 94(12): 1738-41, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16431410

RESUMO

AIM: To define the adverse events following two different rates and methods of intravenous iron sucrose infusions in children with anaemia due to chronic renal impairment. METHODS: Two prospective observational studies were undertaken to characterize the adverse events following iron sucrose administration in children with renal impairment and on erythropoietin. Between January 1999 and April 2003, 5 mg/kg of intravenous (IV) iron sucrose was given over 90 min and repeated 24 h later. Between May 2003 and September 2004, in children with better venous access, a single dose of 2 mg/kg of IV iron sucrose was administered over 3 min during an outpatient clinic visit and haemodialysis sessions. Following infusions, children were monitored for immediate and delayed adverse events. All such events were documented and dealt with appropriately. Test doses were not used. RESULTS: A total of 870 infusions over 90 min were administered to 72 children. Three children developed abdominal pain. One child developed worsening of hypertension (not related to iron sucrose). Sixty-five doses were administered over 3 min to 20 children, and six minor adverse events were documented. CONCLUSION: Although 90 min infusion is associated with fewer adverse events, no life-threatening events were documented in either method.


Assuntos
Anemia/tratamento farmacológico , Eritropoetina/uso terapêutico , Compostos Férricos/administração & dosagem , Compostos Férricos/efeitos adversos , Anemia/etiologia , Criança , Óxido de Ferro Sacarado , Ácido Glucárico , Humanos , Infusões Intravenosas , Falência Renal Crônica/complicações , Estudos Prospectivos , Proteínas Recombinantes
16.
J Mol Cell Cardiol ; 37(2): 603-6, 2004 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15276029

RESUMO

Cardiac hypertrophy is associated with hypertrophic growth of cardiac myocytes and increased fibrosis. Much is known of the stimuli which promote myocyte hypertrophy and the changes associated with the response, but the links between the two are largely unknown. Using subtractive hybridization, we identified three genes which are acutely (<1 h) upregulated in neonatal rat ventricular myocytes exposed to the alpha-adrenergic agonist, phenylephrine. One represented connective tissue growth factor (CTGF) which is implicated in fibrosis and promotes hypertrophy in other cells. We further examined the expression of CTGF mRNA and protein in cardiac myocytes using quantitative PCR and immunoblotting, confirming that phenylephrine increased CTGF mRNA (maximal within 1 h) and protein (increased over 4 - 24 h). Endothelin-1 promoted a greater, though transient, increase in CTGF mRNA, but the increase in CTGF protein was sustained over 8 h. Neither agonist increased CTGF mRNA in cardiac non-myocytes. By increasing the expression of CTGF in cardiac myocytes, hypertrophic agonists such as phenylephrine and endothelin-1 may promote fibrosis. CTGF may also propagate the hypertrophic response initiated by these agonists.


Assuntos
Endotelina-1/farmacologia , Proteínas Imediatamente Precoces/biossíntese , Peptídeos e Proteínas de Sinalização Intercelular/biossíntese , Miócitos Cardíacos/metabolismo , Fenilefrina/farmacologia , Regulação para Cima , Animais , Animais Recém-Nascidos , Fator de Crescimento do Tecido Conjuntivo , Expressão Gênica/efeitos dos fármacos , Ventrículos do Coração/metabolismo , Proteínas Imediatamente Precoces/genética , Peptídeos e Proteínas de Sinalização Intercelular/genética , Miócitos Cardíacos/química , RNA Mensageiro/análise , RNA Mensageiro/metabolismo , Ratos
17.
Biochem Biophys Res Commun ; 307(2): 416-21, 2003 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-12859973

RESUMO

Oxidative stress induces cardiac myocyte apoptosis. At least some effects are probably mediated through changes in gene expression. Using Affymetrix arrays, we examined the changes in gene expression induced by H(2)O(2) (0.04, 0.1, and 0.2mM; 2 and 4h) in rat neonatal ventricular myocytes. Changes in selected upregulated genes were confirmed by ratiometric RT-PCR. p21(Cip1/Waf1) was one of the only two genes upregulated in all conditions studied. Of the heat shock proteins, only Hsp70/70.1 was induced by H(2)O(2) with no change in the expression of Hsp25, Hsp60 or Hsp90. Heme oxygenase 1 was also potently upregulated, but not heme oxygenases 2 or 3. Of the intercellular adhesion proteins, syndecan-1 was significantly upregulated in response to H(2)O(2), with little change in the expression of other syndecans and no change in expression of any of the integrins studied. Thus, oxidative stress, exemplified by H(2)O(2), selectively promotes the expression of specific gene family members.


Assuntos
Perfilação da Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Peróxido de Hidrogênio/farmacologia , Miócitos Cardíacos/efeitos dos fármacos , Oxidantes/farmacologia , Animais , Animais Recém-Nascidos , Inibidor de Quinase Dependente de Ciclina p21 , Ciclinas/genética , Ciclinas/metabolismo , Proteínas de Choque Térmico HSP70/genética , Proteínas de Choque Térmico HSP70/metabolismo , Heme Oxigenase (Desciclizante)/genética , Heme Oxigenase (Desciclizante)/metabolismo , Heme Oxigenase-1 , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Dados de Sequência Molecular , Miócitos Cardíacos/fisiologia , Análise de Sequência com Séries de Oligonucleotídeos , Estresse Oxidativo , Proteoglicanas/genética , Proteoglicanas/metabolismo , Ratos , Ratos Sprague-Dawley , Sindecana-1 , Sindecanas
18.
J Biol Chem ; 278(28): 25542-7, 2003 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-12721309

RESUMO

Oxidative stress promotes cardiac myocyte apoptosis through the mitochondrial death pathway. Since Bcl-2 family proteins are key regulators of apoptosis, we examined the effects of H2O2 on the expression of principal Bcl-2 family proteins (Bcl-2, Bcl-xL, Bax, Bad) in neonatal rat cardiac myocytes. Protein expression was assessed by immunoblotting. Bcl-2, Bax, and Bad were all down-regulated in myocytes exposed to 0.2 mm H2O2, a concentration that induces apoptosis. In contrast, although Bcl-xL levels initially declined, the protein was re-expressed from 4-6 h. Bcl-xL mRNA was up-regulated from 2 to 4 h in neonatal rat or mouse cardiac myocytes exposed to H2O2, consistent with the re-expression of protein. Four different untranslated first exons have been identified for the Bcl-x gene (exons 1, 1B, 1C, and 1D, where exon 1 is the most proximal and exon 1D the most distal to the coding region). All were detected in mouse or rat neonatal cardiac myocytes, but exon 1D was not expressed in adult mouse hearts. In neonatal mouse or rat cardiac myocytes, H2O2 induced the expression of exons 1B, 1C, and 1D, but not exon 1. These data demonstrate that the Bcl-x gene is selectively responsive to oxidative stress, and the response is mediated through distal promoter regions.


Assuntos
Peróxido de Hidrogênio/farmacologia , Miocárdio/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/biossíntese , Proteínas Proto-Oncogênicas c-bcl-2/genética , Animais , Apoptose , Células Cultivadas , Primers do DNA/farmacologia , DNA Complementar/metabolismo , Regulação para Baixo , Éxons , Immunoblotting , Camundongos , Camundongos Endogâmicos C57BL , Modelos Genéticos , Estresse Oxidativo , Regiões Promotoras Genéticas , RNA/metabolismo , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Baço/metabolismo , Fatores de Tempo , Regulação para Cima , Proteína bcl-X
19.
Biochem J ; 368(Pt 1): 101-10, 2002 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-12169099

RESUMO

Cardiac hypertrophy, an important adaptational response, is associated with up-regulation of the immediate early gene, c- jun, which encodes the c-Jun transcription factor. c-Jun may feed back to up-regulate its own transcription and, since the c-Jun N-terminal kinase (JNK) family of mitogen-activated protein kinases (MAPKs) phosphorylate c-Jun(Ser-63/73) to increase its transactivating activity, JNKs are thought to be the principal factors involved in c- jun up-regulation. Hypertrophy in primary cultures of cardiac myocytes is induced by endothelin-1, phenylephrine or PMA, probably through activation of one or more of the MAPK family. These three agonists increased c- jun mRNA with the rank order of potency of PMA approximately endothelin-1>phenylephrine. Up-regulation of c- jun mRNA by endothelin-1 was attenuated by inhibitors of protein kinase C (GF109203X) and the extracellular signal-regulated kinase (ERK) cascade (PD98059 or U0126), but not by inhibitors of the JNK (SP600125) or p38-MAPK (SB203580) cascades. Hyperosmotic shock (0.5 M sorbitol) powerfully activates JNKs, but did not increase c- jun mRNA. These data suggest that ERKs, rather than JNKs, are required for c- jun up-regulation. However, endothelin-1 and phenylephrine induced greater up-regulation of c-Jun protein than PMA and phosphorylation of c-Jun(Ser-63/73) correlated with the level of c-Jun protein. Up-regulation of c-Jun protein by endothelin-1 was attenuated by inhibitors of protein kinase C and the ERK cascade, probably correlating with a primary input of ERKs into transcription. In addition, SP600125 inhibited the phosphorylation of c-Jun(Ser-63/73), attenuated the increase in c-Jun protein induced by endothelin-1 and increased the rate of c-Jun degradation. Thus whereas ERKs are the principal MAPKs required for c- jun transcription, JNKs are necessary to stabilize c-Jun for efficient up-regulation of the protein.


Assuntos
Proteínas Quinases Ativadas por Mitógeno/metabolismo , Miocárdio/metabolismo , Proteínas Proto-Oncogênicas c-jun/metabolismo , Animais , Endotelina-1/farmacologia , Proteínas Quinases JNK Ativadas por Mitógeno , Miocárdio/enzimologia , Pressão Osmótica , Fenilefrina/farmacologia , Proteínas Proto-Oncogênicas c-jun/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Transdução de Sinais , Acetato de Tetradecanoilforbol/farmacologia , Regulação para Cima/efeitos dos fármacos
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