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1.
CJEM ; 26(4): 271-279, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38342855

RESUMO

INTRODUCTION: Women-identifying emergency physicians face gender-based discrimination throughout their careers. The purpose of this study was to explore emergency physician's perceptions and experiences of gender equity in emergency medicine. METHODS: We conducted a secondary analysis of data from a previously conducted survey of Canadian emergency physicians on barriers to gender equity in emergency medicine. Survey responses were analyzed using logistic regression to determine the impact that gender, practice setting, years since graduation, race, equity-seeking status, and parental status had on agreement about gender equity in emergency medicine and five of the problem statements. RESULTS: A total of 710 participants completed the survey. Most identified as women (58.8%), white (77.4%), graduated between 2010 and 2019 (40%), had CCFP (Emergency Medicine) designation (47.9%), an urban practice (84.4%), were parents (62.4%) and did not identify as equity-seeking (79.9%). Women-identifying physicians were less likely to perceive gender equity in emergency medicine, OR 0.52, CI [0.38, 0.73]. Women-identifying physicians were more likely to agree with statements about microaggressions, OR 4.39, CI [2.66, 7.23]; barriers to leadership, OR 3.51, CI [2.25, 5.50]; gender wage gap, OR 13.46, CI [8.27, 21.91]; lack of support for parental leave, OR 2.85, CI [1.82, 4.44]; and education on allyship, OR 2.23 CI [1.44, 3.45] than men-identifying physicians. CONCLUSION: In this study, women-identifying physicians were less likely to perceive that there was gender equity in emergency medicine than men-identifying physicians. Women-identifying physicians agreed that there are greater barriers for career advancement including fewer opportunities for leadership, a gender wage gap, a lack of parental leave policies to support a return to work and a lack of education for men to become allies. Men-identifying physicians were less aware of these inequities. Health systems must work to improve gender equity in emergency medicine and this will require education and allyship from men-identifying physicians.


RéSUMé: INTRODUCTION: Les femmes médecins urgentistes sont confrontées à une discrimination fondée sur le sexe tout au long de leur carrière. L'objectif de cette étude était d'explorer les perceptions et les expériences des médecins urgentistes en matière d'équité entre les sexes en médecine d'urgence. MéTHODES: Nous avons procédé à une analyse secondaire des données d'une enquête menée précédemment auprès des médecins urgentistes canadiens sur les obstacles à l'équité entre les sexes en médecine d'urgence. Les réponses au sondage ont été analysées à l'aide d'une régression logistique pour déterminer l'incidence que le sexe, le milieu de pratique, les années écoulées depuis l'obtention du diplôme, la race, le statut de demandeur d'équité et le statut parental avaient sur l'accord sur l'équité entre les sexes en médecine d'urgence et cinq des énoncés de problème. RéSULTATS: Au total, 710 participants ont répondu à l'enquête. La plupart d'entre eux sont des femmes (58.8 %), de race blanche (77.4 %), ont obtenu leur diplôme entre 2010 et 2019 (40 %), ont le titre de CCMF (médecine d'urgence) (47.9 %), exercent en milieu urbain (84.4 %), sont parents (62.4 %) et ne se déclarent pas en quête d'équité (79.9 %). Les médecins s'identifiant à des femmes étaient moins susceptibles de percevoir l'équité entre les sexes en médecine d'urgence, OR 0.52, IC [0.38,0.73]. Les médecins s'identifiant comme femmes étaient plus susceptibles d'être d'accord avec les déclarations sur les microagressions, OR 4.39, IC [2.66, 7.23] ; obstacles au leadership, OR 3.51, IC [2.25, 5.50] ; écart salarial entre les hommes et les femmes, OR 13.46, IC [8.27, 21.91] ; le manque de soutien pour le congé parental, OR 2.85, IC [1.82, 4.44]; et l'éducation sur l'alliance, OR 2.23 IC [1.44, 3.45] que les médecins s'identifiant comme hommes. CONCLUSION: Dans cette étude, les médecins s'identifiant à des femmes étaient moins susceptibles de percevoir qu'il y avait une équité entre les sexes en médecine d'urgence que les médecins s'identifiant à des hommes. Les femmes médecins s'accordent à dire qu'il existe davantage d'obstacles à l'avancement professionnel, notamment moins d'opportunités de leadership, un écart salarial entre les hommes et les femmes, un manque de politiques de congé parental pour favoriser le retour au travail et un manque d'éducation des hommes pour qu'ils deviennent des alliés. Les médecins s'identifiant à des hommes étaient moins conscients de ces inégalités. Les systèmes de santé doivent s'efforcer d'améliorer l'équité entre les sexes dans la médecine d'urgence, ce qui nécessitera une formation et un allié de la part des médecins qui s'identifient aux hommes.


Assuntos
Medicina de Emergência , Médicas , Médicos , Masculino , Humanos , Feminino , Canadá , Equidade de Gênero
2.
Heart ; 109(21): 1617-1623, 2023 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-37316165

RESUMO

OBJECTIVES: The main aim of this work was to analyse the cost-effectiveness of an integrated care concept (NICC) that combines telemonitoring with the support of a care centre in addition to guideline therapy for patients. Secondary aims were to compare health utility and health-related quality of life (QoL) between NICC and standard of care (SoC). METHODS: The randomised controlled CardioCare MV Trial compared NICC and SoC in patients from Mecklenburg-West Pomerania (Germany) with atrial fibrillation, heart failure or treatment-resistant hypertension. QoL was measured using the EQ-5D-5L at baseline, 6 months and 1 year follow-up. Quality-adjusted life years (QALYs), EQ5D utility scores, Visual Analogue Scale (VAS) Scores and VAS adjusted life years (VAS-AL) were calculated. Cost data were obtained from health insurance companies, and the payer perspective was taken in health economic analyses. Quantile regression was used with adjustments for stratification variables. RESULTS: The net benefit of NICC (QALY) was 0.031 (95% CI 0.012 to 0.050; p=0.001) in this trial involving 957 patients. EQ5D Index values, VAS-ALs and VAS were larger for NICC compared with SoC at 1 year follow-up (all p≤0.004). Direct cost per patient and year were €323 (CI €157 to €489) lower in the NICC group. When 2000 patients are served by the care centre, NICC is cost-effective if one is willing to pay €10 652 per QALY per year. CONCLUSION: NICC was associated with higher QoL and health utility. The programme is cost-effective if one is willing to pay approximately €11 000 per QALY per year.


Assuntos
Doenças Cardiovasculares , Hipertensão , Humanos , Doenças Cardiovasculares/terapia , Análise Custo-Benefício , Qualidade de Vida , Padrão de Cuidado , Hipertensão/diagnóstico , Hipertensão/terapia , Anos de Vida Ajustados por Qualidade de Vida
3.
Eur J Dermatol ; 33(1): 19-24, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-37154811

RESUMO

BACKGROUND: Onychomycosis affects up to 50% of patients in the older population. OBJECTIVES: This study aimed to explore heat sensitivity of Trichophyton rubrum and Trichophyton interdigitale as pathogens of onychomycosis. MATERIALS & METHODS: The fungi were heated in sterile saline solution up to 100°C for five or 10 minutes with or without additional previous treatment with 1% ciclopirox solution or chitinase and 1,3 -galactidase or for 45 minutes at 40°C or 60°C with washing powder. Subsequently, the fungi were cultured and regrowth was assessed after one week. RESULTS: After heating T. rubrum for five minutes at 60°C, growth was completely inhibited. After heating T. interdigitale for five minutes at 60°C, all of the samples regrew, and at 95°C, none of the samples regrew. No difference between five and 10-minute heating was observed. Previous incubation with 1% ciclopirox solution for 24 hours inhibited the growth of T. rubrum completely. T. interdigitale was still able to regrow to 100% after five minutes at 40°C, to 33% after 60°C, and to 22% after 80°C. Incubation for 45 minutes with washing powder solution at 40°C or 60°C did not lead to significant growth reduction of T. rubrum or interdigitale. Two hours incubation with -1,3-glucanase and chitinase prior to five minutes of heating to 60°C and 80°C reduced the heat resistance of T. interdigitale; growth was inhibited in 56% and 100% of the samples, respectively. CONCLUSION: The heat resistance of T. rubrum and interdigitale should be considered using non-medical thermal treatment.


Assuntos
Onicomicose , Humanos , Trichophyton , Ciclopirox/farmacologia , Temperatura Alta , Pós
4.
Eur J Med Res ; 28(1): 22, 2023 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-36631889

RESUMO

IMPORTANCE: Healthcare concepts for chronic diseases based on tele-monitoring have become increasingly important during COVID-19 pandemic. OBJECTIVE: To study the effectiveness of a novel integrated care concept (NICC) that combines tele-monitoring with the support of a call centre in addition to guideline therapy for patients with atrial fibrillation, heart failure, or treatment-resistant hypertension. DESIGN: A prospective, parallel-group, open-label, randomized, controlled trial. SETTING: Between December 2017 and August 2019 at the Rostock University Medical Center (Germany). PARTICIPANTS: Including 960 patients with either atrial fibrillation, heart failure, or treatment-resistant hypertension. INTERVENTIONS: Patients were randomized to either NICC (n = 478) or standard-of-care (SoC) (n = 482) in a 1:1 ratio. Patients in the NICC group received a combination of tele-monitoring and intensive follow-up and care through a call centre. MAIN OUTCOMES AND MEASURES: Three primary endpoints were formulated: (1) composite of all-cause mortality, stroke, and myocardial infarction; (2) number of inpatient days; (3) the first plus cardiac decompensation, all measured at 12-months follow-up. Superiority was evaluated using a hierarchical multiple testing strategy for the 3 primary endpoints, where the first step is to test the second primary endpoint (hospitalization) at two-sided 5%-significance level. In case of a non-significant difference between the groups for the rate of hospitalization, the superiority of NICC over SoC is not shown. RESULTS: The first primary endpoint occurred in 1.5% of NICC and 5.2% of SoC patients (OR: 3.3 [95%CI 1.4-8.3], p = 0.009). The number of inpatient treatment days did not differ significantly between both groups (p = 0.122). The third primary endpoint occurred in 3.6% of NICC and 8.1% of SoC patients (OR: 2.2 [95%CI 1.2-4.2], p = 0.016). Four patients died of all-cause death in the NICC and 23 in the SoC groups (OR: 4.4 [95%CI 1.6-12.6], p = 0.006). Based on the prespecified hierarchical statistical analysis protocol for multiple testing, the trial did not meet its primary outcome measure. CONCLUSIONS AND RELEVANCE: Among patients with atrial fibrillation, heart failure, or treatment-resistant hypertension, the NICC approach was not superior over SoC, despite a significant reduction in all-cause mortality, stroke, myocardial infarction and cardiac decompensation. Trial registration ClinicalTrials.gov Identifier: NCT03317951.


Assuntos
Fibrilação Atrial , COVID-19 , Doenças Cardiovasculares , Insuficiência Cardíaca , Hipertensão , Infarto do Miocárdio , Acidente Vascular Cerebral , Humanos , Doenças Cardiovasculares/terapia , COVID-19/terapia , Fibrilação Atrial/terapia , Pandemias , Estudos Prospectivos , Doença Crônica , Hipertensão/terapia , Insuficiência Cardíaca/terapia
5.
CJEM ; 24(2): 151-160, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35034336

RESUMO

OBJECTIVES: Gender inequities are deeply rooted in our society and have significant negative consequences. Female physicians experience numerous gender-related inequities (e.g., microaggressions, harassment, violence). These inequities have far-reaching consequences on health, well-being and career longevity and may result in the devaluing of various strengths that female emergency physicians bring to the table. This, in turn, has an impact on patient healthcare experience and outcomes. During the 2021 Canadian Association of Emergency Physicians (CAEP) Academic Symposium, a national collaborative sought to understand gender inequities in emergency medicine in Canada. METHODS: We used a multistep stakeholder-engagement-based approach (harnessing both quantitative and qualitative methods) to identify and prioritize problems with gender equity in emergency medicine in Canada. Based on expert consultation and literature review, we developed recommendations to effect change for the higher priority problems. We then conducted a nationwide consultation with the Canadian emergency medicine community via online engagement and the CAEP Academic Symposium to ensure that these priority problems and solutions were appropriate for the Canadian context. CONCLUSION: Via the above process, 15 recommendations were developed to address five unique problem areas. There is a dearth of research in this important area and we hope this preliminary work will serve as a starting point to fuel further research. To facilitate these scholarly endeavors, we have appended additional documents identifying other key problems with gender equity in emergency medicine in Canada as well as proposed next steps for future research.


RéSUMé: OBJECTIFS: Les inégalités entre les sexes sont profondément ancrées dans notre société et ont des conséquences négatives importantes. Les femmes médecins subissent de nombreuses inégalités liées au genre (par exemple, microagressions, harcèlement, violence). Ces inégalités ont des conséquences considérables sur la santé, le bien-être et la longévité de la carrière et peuvent entraîner la dévalorisation des différents atouts que les femmes médecins urgentistes apportent à la table. Ceci, à son tour, a un impact sur l'expérience et les résultats des soins de santé des patients. Au cours du Symposium académique 2021 de l'Association canadienne des médecins d'urgence (ACMU), une collaboration nationale a cherché à comprendre les inégalités entre les sexes en médecine d'urgence au Canada. MéTHODES: Nous avons utilisé une approche en plusieurs étapes basée sur l'engagement des parties prenantes (en utilisant des méthodes quantitatives et qualitatives) pour identifier et classer par ordre de priorité les problèmes d'équité entre les sexes en médecine d'urgence au Canada. À partir d'une consultation d'experts et d'une revue de la littérature, nous avons élaboré des recommandations visant à apporter des changements aux problèmes les plus prioritaires. Nous avons ensuite mené une consultation nationale auprès de la communauté canadienne de médecine d'urgence par le biais d'un engagement en ligne et du symposium universitaire de l'ACMU afin de nous assurer que ces problèmes prioritaires et ces solutions étaient adaptés au contexte canadien. CONCLUSION: Grâce au processus ci-dessus, 15 recommandations ont été élaborées pour traiter 5 domaines problématiques uniques. Il existe un manque de recherche dans ce domaine important et nous espérons que ce travail préliminaire servira de point de départ pour alimenter d'autres recherches. Pour faciliter ces efforts de recherche, nous avons annexé d'autres documents identifiant d'autres problèmes clés en matière d'équité entre les sexes en médecine d'urgence au Canada, ainsi que des propositions d'étapes pour de futures recherches.


Assuntos
Medicina de Emergência , Liderança , Canadá , Feminino , Equidade de Gênero , Humanos , Sociedades Médicas
6.
Trials ; 21(1): 131, 2020 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-32014033

RESUMO

BACKGROUND: Cardiovascular diseases are the major cause of death globally and represent a major economic burden on health care systems. For patients with heart failure, atrial fibrillation or therapy-resistant hypertension, we have developed a novel integrated care concept (NICC) which combines telemedicine with intensive support by a care center, including a call center, an integrated care network including inpatient and outpatient care providers and guideline therapy for patients (Schmidt et al. 2018 Trials 19:120). Here, we describe challenges and solutions in patient recruitment and provide the statistical analysis plan. METHODS: The study CardioCare MV is a prospective, randomized, controlled, parallel-group, open-label, bi-center trial with two groups for comparing NICC with standard of care (SoC). Because of issues with patient enrollment we adapted the study plan after consultation with the Ethics Committee and the funding agency. We altered the analysis strategy for the primary endpoints, which led to a change in the required sample size. We also changed the access points to patients from inpatient hospitals specialized in the treatment of patients with cardiovascular disease to specialized practices. RESULTS: Recruitment of patients started on 1 December 2017, and first patient in was on 4 December 2017. Recruitment was completed on 15 August 2019 as planned according to the amended study plan. The follow-up period will end in August 2020. A total of 964 patients was enrolled into the trial. The statistical analysis plan was finalized prior to last patient in. Results will be available by the end of 2020. DISCUSSION: The trial will inform care providers whether quality of care can be improved by an integrated care concept providing telemedicine through a round-the-clock call center approach. We expect that cost of the NICC will be lower than standard care because of reduced hospitalizations. The trial will guide additional research to disentangle the effects of this complex intervention. TRIAL REGISTRATION: DRKS, ID: DRKS00013124. Registered on 5 October 2017 ClinicalTrials.gov, ID: NCT03317951. Registered on 17 October 2017.


Assuntos
Fibrilação Atrial/terapia , Prestação Integrada de Cuidados de Saúde/métodos , Insuficiência Cardíaca/terapia , Hipertensão/terapia , Estudos Multicêntricos como Assunto/estatística & dados numéricos , Seleção de Pacientes , Ensaios Clínicos Controlados Aleatórios como Assunto/estatística & dados numéricos , Telemedicina/métodos , Doença Crônica , Seguimentos , Humanos , Tempo de Internação , Estudos Prospectivos , Padrão de Cuidado
7.
Trials ; 19(1): 120, 2018 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-29458404

RESUMO

BACKGROUND: Cardiovascular diseases are the major cause of death globally and represent a major economic burden on health care systems. Positive effects of disease management programs have been shown for patients with heart failure (HF). Remote monitoring and telemonitoring with active intervention are beneficial in atrial fibrillation (AF) and therapy-resistant hypertension (TRH), respectively. For these patients, we have developed a novel integrated care concept (NICC) which combines telemedicine with intensive support by a care center, including a call center, an integrated care network including inpatient and outpatient care providers and guideline therapy for patients. METHODS: The aim of the study is to demonstrate the superiority of NICC over guideline therapy alone. The trial is designed as open-label, bi-center, parallel-group design with two groups and a blinded observer. Patients will be included if they are either inpatients or if they are referred to the outpatient clinic of the hospitals by their treating physician. Randomization will be done individually with stratification by cardiovascular disease (AF, HF, TRH), center and admission type. Primary endpoints are based on the 1-year observation period after randomization. The first primary endpoint is the composite endpoint consisting of mortality, stroke and myocardial infarction. The number of hospitalizations form the second primary endpoint. The third primary endpoint is identical to the first primary endpoint plus cardiac decompensation. Adjustments for multiple testing are done using a fall-back strategy. Secondary endpoints include patient adherence, health care costs, quality of life, and safety. A sample size of 2930 gives 80% power at the two-sided 2.5% test level for the first primary endpoint. The power for the second primary endpoint is 99.8% at this sample size, and it is 80% with 1086 patients. DISCUSSION: This study will inform care providers whether quality of care can be improved by an integrated care concept providing telemedicine through a round-the-clock call center approach. We expect that cost of the NICC will be lower than standard care because of reduced hospitalizations. If the study has a positive result, NICC is planned to be immediately rolled out in the federal state of Mecklenburg-West Pomerania and other federal states in Germany. The trial will also guide additional research to disentangle the effects of this complex intervention. TRIAL REGISTRATION: DRKS, ID: DRKS00013124 . Registered on 5 October 2017; ClinicalTrials.gov , ID: NCT03317951. Registered on 17 October 2017.


Assuntos
Fibrilação Atrial/terapia , Prestação Integrada de Cuidados de Saúde , Insuficiência Cardíaca/terapia , Hipertensão/terapia , Ensaios Clínicos Controlados Aleatórios como Assunto , Doença Crônica , Interpretação Estatística de Dados , Determinação de Ponto Final , Humanos , Estudos Prospectivos , Projetos de Pesquisa , Tamanho da Amostra , Telemedicina
8.
Eur J Anaesthesiol ; 34(9): 623-627, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28763317

RESUMO

BACKGROUND: The development of liver failure is a major problem in critically ill patients. The hepatotoxicity of many drugs, as one important reason for liver failure, is poorly screened for in human models. Rocuronium and succinylcholine are neuromuscular blocking agents used for tracheal intubation and for rapid-sequence induction. OBJECTIVE: We used an in-vitro test with a permanent cell line and compared rocuronium and succinylcholine for hepatotoxicity. DESIGN: In-vitro study. SETTING: A basic science laboratory, University Hospital Rostock, Germany. MATERIAL/(PATIENTS): The basic test compound is the permanent human liver cell line HepG2/C3A. In a standardised microtitre plate assay the toxicity of different concentrations of rocuronium, succinylcholine and plasma control was tested. INTERVENTIONS: After two incubation periods of 3 days, the viability of cells (XTT test, lactate dehydrogenase release and trypan blue staining), micro-albumin synthesis and the cytochrome 1A2 activity (metabolism of ethoxyresorufin) were measured. MAIN OUTCOME MEASURES: Differences between rocuronium and succinylcholine were assessed using the Kruskal-Wallis one-way test and two-tailed Mann-Whitney U test. RESULTS: Rocuronium, but not succinylcholine, led to a significant dose-dependent decrease of viability, albumin synthesis and cytochrome 1A2 activity of test cells. CONCLUSION: An in-vitro test with a cell line showed hepatotoxicity of rocuronium that was dose-dependent. Further studies are needed to investigate the underlying mechanisms of the effects of rocuronium on hepatic cellular integrity. TRIAL REGISTRATION: Not suitable.


Assuntos
Fígado/efeitos dos fármacos , Fármacos Neuromusculares Despolarizantes/efeitos adversos , Fármacos Neuromusculares não Despolarizantes/efeitos adversos , Rocurônio/efeitos adversos , Succinilcolina/efeitos adversos , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Células Hep G2 , Humanos , Fígado/citologia , Bloqueio Neuromuscular/efeitos adversos , Bloqueio Neuromuscular/métodos , Fármacos Neuromusculares Despolarizantes/administração & dosagem , Fármacos Neuromusculares não Despolarizantes/administração & dosagem , Rocurônio/administração & dosagem , Succinilcolina/administração & dosagem
9.
Stud Health Technol Inform ; 209: 114-20, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25980713

RESUMO

Patients presenting to a rural emergency department (ED) with mental health symptoms have difficulty accessing services of mental health professionals [1,2]. Videoconferencing (VC) has been found to improve patient access to health services that require specialist care in rural EDs [3,4,5]. Although previous studies highlight the benefit of using VC for patients presenting with mental health emergencies, no study has investigated the current views and use of VC for mental health emergencies in EDs in Southwestern Ontario [3,5,6]. To explore the views of ED staff regarding the use of VC in mental health emergencies, structured telephone interviews were conducted with representatives from EDs in the Erie St. Clair and Southwest Local Health Integration Networks (LHIN). Participants noted that using VC for mental health emergencies may improve patient experience and benefit crisis response teams. VC was perceived by some participants as a means to expedite the direct assessment of a patient presenting with a mental health emergency by a mental health specialist. However several participants stated that using VC for mental health emergencies strains ED resources. Lack of use and difficulty accessing a psychiatrist were identified as potential barriers to implementing the use of VC for mental health emergencies.


Assuntos
Atitude do Pessoal de Saúde , Serviço Hospitalar de Emergência/estatística & dados numéricos , Serviços de Emergência Psiquiátrica/estatística & dados numéricos , Transtornos Mentais/terapia , Consulta Remota/estatística & dados numéricos , Comunicação por Videoconferência/estatística & dados numéricos , Transtornos Mentais/diagnóstico , Transtornos Mentais/epidemiologia , Ontário/epidemiologia , Serviços de Saúde Rural/estatística & dados numéricos , População Rural
10.
Proc Natl Acad Sci U S A ; 110(51): 20771-6, 2013 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-24302763

RESUMO

Experience-driven circuit changes underlie learning and memory. Monocular deprivation (MD) engages synaptic mechanisms of ocular dominance (OD) plasticity and generates robust increases in dendritic spine density on L5 pyramidal neurons. Here we show that the paired immunoglobulin-like receptor B (PirB) negatively regulates spine density, as well as the threshold for adult OD plasticity. In PirB(-/-) mice, spine density and stability are significantly greater than WT, associated with higher-frequency miniature synaptic currents, larger long-term potentiation, and deficient long-term depression. Although MD generates the expected increase in spine density in WT, in PirB(-/-) this increase is occluded. In adult PirB(-/-), OD plasticity is larger and more rapid than in WT, consistent with the maintenance of elevated spine density. Thus, PirB normally regulates spine and excitatory synapse density and consequently the threshold for new learning throughout life.


Assuntos
Dominância Ocular/fisiologia , Potenciais Pós-Sinápticos Excitadores/fisiologia , Aprendizagem/fisiologia , Potenciação de Longa Duração/fisiologia , Células Piramidais/metabolismo , Receptores Imunológicos/metabolismo , Animais , Camundongos , Camundongos Knockout , Células Piramidais/citologia , Receptores Imunológicos/genética
11.
Biotechnol Bioeng ; 110(3): 887-97, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23096577

RESUMO

Biosynthetic thiolases catalyze the condensation of two molecules acetyl-CoA to acetoacetyl-CoA and represent key enzymes for carbon-carbon bond forming metabolic pathways. An important biotechnological example of such a pathway is the clostridial n-butanol production, comprising various natural constraints that limit titer, yield, and productivity. In this study, the thiolase of Clostridium acetobutylicum, the model organism for solventogenic clostridia, was specifically engineered for reduced sensitivity towards its physiological inhibitor coenzyme A (CoA-SH). A high-throughput screening assay in 96-well microtiter plates was developed employing Escherichia coli as host cells for expression of a mutant thiolase gene library. Screening of this library resulted in the identification of a thiolase derivative with significantly increased activity in the presence of free CoA-SH. This optimized thiolase comprised three amino acid substitutions (R133G, H156N, G222V) and its gene was expressed in C. acetobutylicum ATCC 824 to assess the effect of reduced CoA-SH sensitivity on solvent production. In addition to a clearly delayed ethanol and acetone formation, the ethanol and butanol titers were increased by 46% and 18%, respectively, while the final acetone concentrations were similar to the vector control strain. These results demonstrate that thiolase engineering constitutes a suitable methodology applicable to improve clostridial butanol production, but other biosynthetic pathways involving thiolase-mediated carbon flux limitations might also be subjected to this new metabolic engineering approach.


Assuntos
Acetil-CoA C-Acetiltransferase/genética , Acetil-CoA C-Acetiltransferase/metabolismo , Butanóis/metabolismo , Clostridium acetobutylicum/enzimologia , Engenharia Metabólica , Acetona/metabolismo , Substituição de Aminoácidos , Clostridium acetobutylicum/genética , Análise Mutacional de DNA , Escherichia coli/genética , Escherichia coli/metabolismo , Etanol/metabolismo , Expressão Gênica , Ensaios de Triagem em Larga Escala
12.
Biotechnol Lett ; 34(9): 1643-9, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22618238

RESUMO

The toxicity of n-butanol in microbial fermentations limits its formation. The stress response of Clostridium acetobutylicum involves various stress proteins and therefore, over-expression of genes encoding stress proteins constitutes an option to improve solvent tolerance. Over-expression of groESL, grpE and htpG, significantly improved butanol tolerance of C. acetobutylicum. Whereas the wild type and vector control strain did not survive 2 % (v/v) butanol for 2 h, the recombinant strains showed 45 % (groESL), 25 % (grpE) and 56 % (htpG), respectively, of the initial c.f.u. after 2 h of butanol exposure. As previously, over-expression of groESL led to higher butanol production rates, but the novel strains over-expressing grpE or htpG produced only 51 and 68 %, respectively, of the wild type butanol concentrations after 72 h clearly differentiating butanol tolerance and production. Not only butanol tolerance but also the adaptation to butanol in successive stress experiments was significantly facilitated by increased levels of GroESL, GrpE and HtpG. Re-transformation and sequence analyses of the plasmids confirmed that not the plasmids, but the host cells evolved to a more robust phenotype.


Assuntos
Adaptação Fisiológica , Butanóis/toxicidade , Clostridium acetobutylicum/efeitos dos fármacos , Clostridium acetobutylicum/genética , Dosagem de Genes , Expressão Gênica , Proteínas de Choque Térmico/biossíntese , Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/genética , Chaperoninas/biossíntese , Chaperoninas/genética , Proteínas de Choque Térmico HSP90/biossíntese , Proteínas de Choque Térmico HSP90/genética , Proteínas de Choque Térmico/genética , Viabilidade Microbiana/efeitos dos fármacos , Plasmídeos , Fatores de Tempo
13.
Eur J Neurosci ; 22(11): 2735-43, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16324107

RESUMO

The purpose of this study was to investigate the role of intracellular calcium buffering in retinal ganglion cells. We performed a quantitative analysis of calcium homeostasis in ganglion cells of early postnatal and adult mice by simultaneous patch-clamp recordings in sliced tissue and microfluorometric calcium measurements with Fura-2. Endogenous calcium homeostasis was quantified by using the 'added buffer' approach which uses amplitudes and decay time constants of calcium transients to give a standard for intracellular calcium buffering. The recovery phase of depolarization-induced calcium transients was well approximated by a mono-exponential function with a decay time constant that showed a linear dependence on dye concentration. Endogenous calcium binding ratios were found to be 575 (n = 18 cells) in early postnatal and 121 (n = 18 cells) in adult retinal ganglion cells. With respect to ganglion cell degeneration at early postnatal stages, our measurements suggest that neuroprotection of a majority of developing ganglion cells partially results from a specialized calcium homeostasis based on high buffering capacities. Furthermore, the dramatic decrease of the intracellular calcium buffering capacity during ganglion cell development may enhance their vulnerability to neurodegeneration.


Assuntos
Envelhecimento/fisiologia , Cálcio/fisiologia , Células Ganglionares da Retina/fisiologia , Algoritmos , Animais , Soluções Tampão , Sinalização do Cálcio/fisiologia , Eletrofisiologia , Homeostase/fisiologia , Técnicas In Vitro , Cinética , Camundongos , Técnicas de Patch-Clamp , Retina/crescimento & desenvolvimento
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