Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 80
Filtrar
1.
Eur Child Adolesc Psychiatry ; 28(8): 1087-1095, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30610380

RESUMO

Despite sizeable short-term effects of neurofeedback (NF) therapy on attention-deficit and hyperactivity disorder (ADHD), longer-term clinical, comorbidity and self-regulation outcomes are less systematically studied. The aim of this largest NF follow-up to date was to evaluate these outcomes 6 months after NF compared to a semi-active control to disentangle specific from unspecific sustained effects. We performed a multicenter, randomized, parallel, controlled, clinical, superiority trial in five German university outpatient departments. Participants were eligible if they fulfilled DSM-IV-TR criteria for ADHD and were aged from 7 to 9 years. Participants were randomly assigned (1:1-ratio) to 25 sessions of slow cortical potential (SCP)-NF or electromyogram biofeedback (EMG-BF). Participants were not blinded, since they received instructions according to each treatment setting. Primary outcomes were parent ratings of ADHD. The trial was registered, number ISRCTN761871859. Both groups showed improvement of ADHD symptoms compared to baseline at 6-months follow-up with large effect sizes for SCP-NF (d = 1.04) and EMG-BF (d = 0.85), but without group differences. When analyzing all assessments (pre-test, post-test-1, post-test-2 and follow-up), a group-by-time interaction emerged (p = 0.0062), with SCP-NF showing stable improvement following treatment but EMG-BF showing a relapse from post-test-1 to post-test-2, and subsequent remission at follow-up. Six months after the end of treatment, improvement after SCP-NF remained large and stable. However, the lack of group differences at follow-up suggests shared specific and unspecific effects contributing to this clinical outcome. Our correlational results indicate specificity of SCP-NF for selected subscales after training, but not at follow-up.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Neurorretroalimentação/métodos , Criança , Comorbidade , Feminino , Humanos , Masculino , Fatores de Tempo , Resultado do Tratamento
2.
Am J Transplant ; 18(5): 1197-1205, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29024364

RESUMO

The relationship between healthcare utilization before and after liver transplantation (LT), and its association with center characteristics, is incompletely understood. This was a retrospective cohort study of 34 402 adult LTs between 2002 and 2013 using Vizient inpatient claims data linked to the United Network for Organ Sharing (UNOS) database. Multivariable mixed-effects linear regression models evaluated the association between hospitalization 90 days pre-LT and the number of days alive and out of the hospital (DAOH) 1 year post-LT. Of those patients alive at LT discharge, 24.7% spent ≥30 days hospitalized during the first year. Hospitalization in the 90 days pre-LT was inversely associated with DAOH (ß = -3.4 DAOH/week hospitalized pre-LT; P = .002). Centers with >30% of their liver transplant recipients hospitalized ≥30 days in the first LT year were typically smaller volume and/or transplanting higher risk recipients (Model for End-Stage Liver Disease [MELD] score ≥35, inpatient or ventilated pre-LT). In conclusion, pre-LT hospitalization predicts 1-year post-LT hospitalization independent of MELD score at the patient-level, whereas center-specific post-LT healthcare utilization is associated with certain center behaviors and selection practices.


Assuntos
Doença Hepática Terminal/cirurgia , Hospitalização/estatística & dados numéricos , Hospitais com Alto Volume de Atendimentos/estatística & dados numéricos , Hospitais com Baixo Volume de Atendimentos/estatística & dados numéricos , Transplante de Fígado/métodos , Aceitação pelo Paciente de Cuidados de Saúde , Transplantados/estatística & dados numéricos , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Readmissão do Paciente , Prognóstico , Estudos Retrospectivos , Índice de Gravidade de Doença
3.
Am J Transplant ; 16(9): 2684-94, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-26946333

RESUMO

Assessment of major adverse cardiovascular events (MACE) after liver transplantation (LT) has been limited by the lack of a multicenter study with detailed clinical information. An integrated database linking information from the University HealthSystem Consortium and the Organ Procurement and Transplant Network was analyzed using multivariate Poisson regression to assess factors associated with 30- and 90-day MACE after LT (February 2002 to December 2012). MACE was defined as myocardial infarction (MI), heart failure (HF), atrial fibrillation (AF), cardiac arrest, pulmonary embolism, and/or stroke. Of 32 810 recipients, MACE hospitalizations occurred in 8% and 11% of patients at 30 and 90 days, respectively. Recipients with MACE were older and more likely to have a history of nonalcoholic steatohepatitis (NASH), alcoholic cirrhosis, MI, HF, stroke, AF and pulmonary and chronic renal disease than those without MACE. In multivariable analysis, age >65 years (incidence rate ratio [IRR] 2.8, 95% confidence interval [95% CI] 1.8-4.4), alcoholic cirrhosis (IRR 1.6, 95% CI 1.2-2.2), NASH (IRR 1.6, 95% CI 1.1-2.4), pre-LT creatinine (IRR 1.1, 95% CI 1.04-1.2), baseline AF (IRR 6.9, 95% CI 5.0-9.6) and stroke (IRR 6.3, 95% CI 1.6-25.4) were independently associated with MACE. MACE was associated with lower 1-year survival after LT (79% vs. 88%, p < 0.0001). In a national database, MACE occurred in 11% of LT recipients and had a negative impact on survival. Pre-LT AF and stroke substantially increase the risk of MACE, highlighting potentially high-risk LT candidates.


Assuntos
Fibrilação Atrial/etiologia , Insuficiência Cardíaca/etiologia , Transplante de Fígado/efeitos adversos , Infarto do Miocárdio/etiologia , Adolescente , Adulto , Idoso , Fibrilação Atrial/patologia , Feminino , Seguimentos , Sobrevivência de Enxerto , Insuficiência Cardíaca/patologia , Humanos , Hepatopatias/cirurgia , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/patologia , Prognóstico , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Adulto Jovem
4.
Herzschrittmacherther Elektrophysiol ; 26(2): 82-93, 2015 Jun.
Artigo em Alemão | MEDLINE | ID: mdl-26001359

RESUMO

Congenital electrical and structural cardiomyopathies are rare and associated with an increased risk for syncope and sudden cardiac death in the young. Due to the young age of the patients and the limited data available, risk stratification and especially ICD therapy are challenging. In this young patient collective, ICD therapy is associated with a high complication rate, which does not justify unreserved primary prophylactic ICD implantation. The aim of this review is to elucidate risk stratification and ICD therapy of various electrical and structural cardiomyopathies.


Assuntos
Arritmias Cardíacas/congênito , Arritmias Cardíacas/prevenção & controle , Cardiomiopatias/congênito , Cardiomiopatias/prevenção & controle , Arritmias Cardíacas/diagnóstico , Cardiomiopatias/diagnóstico , Desfibriladores Implantáveis , Medicina Baseada em Evidências , Feminino , Humanos , Masculino , Seleção de Pacientes , Prevenção Primária/métodos , Prevenção Secundária/métodos , Resultado do Tratamento
5.
Herz ; 39(4): 429-36, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24743921

RESUMO

Syncope accounts for approximately 1 % of visits to emergency departments. The first diagnostic step is to rule out nonsyncopal conditions as a cause of the transient loss of consciousness. Next, the basic clinical evaluation should identify patients at high risk for potentially life-threatening events. These patients should be admitted and monitored until a diagnosis is made and definitive treatment can be offered. Guided by the basic evaluation findings, specific tests should be performed to prove or rule out the suspected diagnosis. In low-risk patients, this should preferably be done in an outpatient setting. To date, there is no consensus on a structured algorithm for the evaluation of patients with syncope. Therefore, it seems beneficial to formulate an algorithm based on the current guidelines for the management of syncope for use in the clinical setting.


Assuntos
Eletrocardiografia/métodos , Serviços Médicos de Emergência/métodos , Anamnese/métodos , Exame Físico/métodos , Síncope/classificação , Síncope/diagnóstico , Diagnóstico Diferencial , Humanos , Prognóstico , Medição de Risco/métodos , Síncope/terapia
6.
Pediatr Obes ; 7(6): 453-60, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22941950

RESUMO

OBJECTIVE: To investigate the association of the neuropeptide Y (NPY) promoter polymorphism rs16147 with body mass index (BMI) during the course of development from infancy to adulthood. DESIGN: Longitudinal, prospective study of a German community sample. SUBJECTS: n = 306 young adults (139 males, 167 females). MEASUREMENTS: Participants' body weight and height were assessed at the ages of 3 months and 2, 4.5, 8, 11, 15 and 19 years. NPY rs16147 was genotyped. RESULTS: Controlling for a number of possible confounders, homozygote carriers of the rs16147 C allele exhibited significantly lower BMI scores when compared with individuals carrying the T allele. In addition, a significant genotype by age interaction emerged, indicating that the genotype effect increased during the course of development. CONCLUSIONS: This is the first longitudinal study to report an association between rs16147 and BMI during childhood and adolescence. The finding that this effect increased during the course of development may either be due to age-dependent alterations in gene expression or to maturation processes within the weight regulation circuits of the central nervous system.


Assuntos
Índice de Massa Corporal , Peso Corporal/genética , Neuropeptídeo Y/genética , Adolescente , Criança , Pré-Escolar , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Genótipo , Humanos , Lactente , Estudos Longitudinais , Masculino , Polimorfismo Genético , Regiões Promotoras Genéticas/genética , Adulto Jovem
7.
Eur J Vasc Endovasc Surg ; 44(1): 93-9, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22580402

RESUMO

OBJECTIVE: To report a multi-center experience with the novel Hemodialysis Reliable Outflow (HeRO) vascular access graft. MATERIALS AND METHODS: Four centers conducted a retrospective review of end stage renal disease patients who received the HeRO device from implant to last available follow-up. Data is available on 164 patients with an accumulated 2092.1 HeRO implant months. RESULTS: At 6 months, HeRO primary and secondary patency is 60% and 90.8%, respectively and at 12 months, 48.8% and 90.8%, respectively. At 24 months, HeRO had a primary patency of 42.9% and secondary patency was 86.7%. Interventions to maintain or re-establish patency have been required in 71.3% of patients (117/164) resulting in an intervention rate of 1.5/year. Access related infections have been reported in 4.3% patients resulting in a rate of 0.14/1000 implant days. CONCLUSIONS: In our experience the HeRO device has performed comparably to standard AVGs and has proven superior to TDCs in terms of patency, intervention, and infection rates when compared to the peer-reviewed literature. As an alternative to catheter dependence as a means for hemodialysis access, this graft could reduce the morbidity and mortality associated with TDCs and have a profound impact on the costs associated with catheter related infections and interventions.


Assuntos
Prótese Vascular , Cateteres de Demora , Análise de Falha de Equipamento/métodos , Falência Renal Crônica/terapia , Diálise Renal/instrumentação , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Desenho de Prótese , Estudos Retrospectivos , Adulto Jovem
8.
Am J Transplant ; 11(4): 798-807, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21401867

RESUMO

Liver transplantation has evolved over the past four decades into the most effective method to treat end-stage liver failure and one of the most expensive medical technologies available. Accurate understanding of the financial implication of recipient severity of illness is crucial to assessing the economic impact of allocation policies. A novel database of linked clinical data from the Organ Procurement and Transplantation Network with cost accounting data from the University HealthSystem Consortium was used to analyze liver transplant costs for 15,813 liver transplants. This data was then utilized to consider the economic impact of alternative allocation systems designed to increase sharing of liver allografts using simulation results. Transplant costs were strongly associated with recipient severity of illness as assessed by the MELD score (p < 0.0001); however, this relationship was not linear. Simulation analysis of the reallocation of livers from low MELD patients to high MELD using a two-tiered regional sharing approach (MELD 15/25) resulted in 88 fewer deaths annually at estimated cost of $17,056 per quality-adjusted life-year saved. The results suggest that broader sharing of liver allografts offers a cost-effective strategy to reduce the mortality from end stage liver disease.


Assuntos
Doença Hepática Terminal/prevenção & controle , Falência Hepática/economia , Transplante de Fígado/economia , Modelos Econômicos , Obtenção de Tecidos e Órgãos/economia , Adolescente , Adulto , Criança , Estudos de Coortes , Custos e Análise de Custo , Feminino , Humanos , Falência Hepática/diagnóstico , Falência Hepática/cirurgia , Masculino , Pessoa de Meia-Idade , Índice de Gravidade de Doença , Doadores de Tecidos , Adulto Jovem
9.
Platelets ; 21(8): 648-57, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20942599

RESUMO

Both, the activity of transcription factors as well as epigenetic alterations in defined DNA regions regulate cellular differentiation processes. Hence, neuronal differentiation from neural progenitor cells is promoted by the transcription factor all trans retinoic acid (ATRA) and the histone deacetylase inhibitor valproic acid (VPA). VPA has also been shown to be involved in differentiation of tumor cells and to greatly improve the reprogramming of human somatic cells to induced pluripotent stem cells. Here we have investigated the impact of ATRA and VPA on the differentiation of megakaryoctes and platelets from the megakaryocyte progenitor cell line MEG-01. Our results show that treatment with ATRA (10⁻¹¹ M) and VPA (2 × 10⁻³ M) induces megakaryopoiesis of MEG-01 cells as estimated by polyploidy, formation of characteristic proplatelets and elevated expression of the megakaryocytic markers CD41 and CD61. The resulting megakaryocytes stayed viable for more than 3 weeks and shed platelet-like particles positive for CD41, CD61 and CD42b into the supernatant. Platelet-like particles responded to thrombin receptor activating peptide (TRAP-6) with increased externalization of P-selectin. Thus, ATRA and VPA proved to be efficient agents for the gentle induction of megakaryopoiesis and thrombopoiesis of MEG-01 cells providing the possibility to study molecular events underlying megakaryopoiesis and human platelet production over longer time periods.


Assuntos
Plaquetas/metabolismo , Diferenciação Celular/efeitos dos fármacos , Células Progenitoras de Megacariócitos , Megacariócitos , Tretinoína/farmacologia , Ácido Valproico/farmacologia , Animais , Antineoplásicos/farmacologia , Linhagem Celular , Inibidores de Histona Desacetilases/farmacologia , Humanos , Células Progenitoras de Megacariócitos/citologia , Células Progenitoras de Megacariócitos/efeitos dos fármacos , Células Progenitoras de Megacariócitos/fisiologia , Megacariócitos/citologia , Megacariócitos/efeitos dos fármacos , Megacariócitos/fisiologia , Fragmentos de Peptídeos/farmacologia , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/metabolismo , Glicoproteína IIb da Membrana de Plaquetas/metabolismo , Acetato de Tetradecanoilforbol/farmacologia , Fatores de Transcrição/metabolismo
10.
Appl Environ Microbiol ; 71(10): 6185-92, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16204537

RESUMO

The recently described respiratory strain Saccharomyces cerevisiae KOY.TM6*P is, to our knowledge, the only reported strain of S. cerevisiae which completely redirects the flux of glucose from ethanol fermentation to respiration, even at high external glucose concentrations (27). In the KOY.TM6*P strain, portions of the genes encoding the predominant hexose transporter proteins, Hxt1 and Hxt7, were fused within the regions encoding transmembrane (TM) domain 6. The resulting chimeric gene, TM6*, encoded a chimera composed of the amino-terminal half of Hxt1 and the carboxy-terminal half of Hxt7. It was subsequently integrated into the genome of an hxt null strain. In this study, we have demonstrated the transferability of this respiratory phenotype to the V5 hxt1-7Delta strain, a derivative of a strain used in enology. We also show by using this mutant that it is not necessary to transform a complete hxt null strain with the TM6* construct to obtain a non-ethanol-producing phenotype. The resulting V5.TM6*P strain, obtained by transformation of the V5 hxt1-7Delta strain with the TM6* chimeric gene, produced only minor amounts of ethanol when cultured on external glucose concentrations as high as 5%. Despite the fact that glucose flux was reduced to 30% in the V5.TM6*P strain compared with that of its parental strain, the V5.TM6*P strain produced biomass at a specific rate as high as 85% that of the V5 wild-type strain. Even more relevant for the potential use of such a strain for the production of heterologous proteins and also of low-alcohol beverages is the observation that the biomass yield increased 50% with the mutant compared to its parental strain.


Assuntos
Engenharia Genética/métodos , Glucose/metabolismo , Consumo de Oxigênio/fisiologia , Saccharomyces cerevisiae/fisiologia , Transformação Genética , Vinho/microbiologia , Meios de Cultura , Etanol/metabolismo , Fermentação , Frutose/metabolismo , Proteínas Facilitadoras de Transporte de Glucose , Proteínas de Transporte de Monossacarídeos/genética , Proteínas de Transporte de Monossacarídeos/metabolismo , Fenótipo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo
11.
Curr Genet ; 40(1): 27-39, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11570514

RESUMO

Using transposon mutagenesis in the haploid Saccharomyces cerevisiae strain W303-1A we have identified genes required for growth in high salt medium, survival of a hypo-osmotic shock and growth at 15 degrees C. Screening 25,000 transposon insertions revealed a total of 61 insertions that caused salt-sensitivity; and those insertions affected 31 genes. Only 12 of those genes were previously known to be required for salt-tolerance. Among the 61 insertions, three caused general osmo-sensitivity. We identified one single insertion mutant in the already-known gene, FPS1, required for survival of hypo-osmotic shock. A total of 31 insertions caused failure to grow at low temperature. Those identified ten different genes, three of which had previously been reported to affect cold-tolerance. Four genes were identified in both the salt and the cold-sensitivity screen. We found several unusual insertion mutations: (1) insertions in or close to essential genes, (2) insertion in an intergenic region and (3) insertions causing stress-sensitivity in W303-1A, while the deletion mutant in BY4741 did not show such a phenotype. Surprisingly, our mutant set and that reported in the large-scale transposon insertion project (TRIPLES, http://ygacmed.yale.edu/triples/triples.htm) only marginally overlap. We discuss some of the features of transposon mutagenesis in light of the availability of the complete set of yeast deletion mutants and we discuss the possible roles of the genes we identified.


Assuntos
Genes Fúngicos , Mutagênese Insercional , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/genética , Sequência de Bases , Temperatura Baixa , Elementos de DNA Transponíveis/genética , Deleção de Genes , Mutação , Pressão Osmótica , Fenótipo , Saccharomyces cerevisiae/metabolismo , Cloreto de Sódio
12.
J Biol Chem ; 276(39): 36543-9, 2001 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-11445582

RESUMO

Fps1p is a glycerol efflux channel from Saccharomyces cerevisiae. In this atypical major intrinsic protein neither of the signature NPA motifs of the family, which are part of the pore, is preserved. To understand the functional consequences of this feature, we analyzed the pseudo-NPA motifs of Fps1p by site-directed mutagenesis and assayed the resultant mutant proteins in vivo. In addition, we took advantage of the fact that the closest bacterial homolog of Fps1p, Escherichia coli GlpF, can be functionally expressed in yeast, thus enabling the analysis in yeast cells of mutations that make this typical major intrinsic protein more similar to Fps1p. We observed that mutations made in Fps1p to "restore" the signature NPA motifs did not substantially affect channel function. In contrast, when GlpF was mutated to resemble Fps1p, all mutants had reduced activity compared with wild type. We rationalized these data by constructing models of one GlpF mutant and of the transmembrane core of Fps1p. Our model predicts that the pore of Fps1p is more flexible than that of GlpF. We discuss the fact that this may accommodate the divergent NPA motifs of Fps1p and that the different pore structures of Fps1p and GlpF may reflect the physiological roles of the two glycerol facilitators.


Assuntos
Aquaporinas , Proteínas de Escherichia coli , Proteínas Fúngicas/química , Proteínas de Membrana/química , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/química , Motivos de Aminoácidos , Proteínas da Membrana Bacteriana Externa/metabolismo , Membrana Celular/metabolismo , Primers do DNA/metabolismo , Escherichia coli/metabolismo , Glicerol/metabolismo , Immunoblotting , Modelos Moleculares , Mutagênese Sítio-Dirigida , Mutação , Plasmídeos/metabolismo , Mutação Puntual , Ligação Proteica , Estrutura Terciária de Proteína , Fatores de Tempo
13.
Mol Microbiol ; 40(5): 1067-83, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11401713

RESUMO

A major part of the transcriptional response of yeast cells to osmotic shock is controlled by the HOG pathway and several downstream transcription factors. Sko1p is a repressor that mediates HOG pathway-dependent regulation by binding to CRE sites in target promoters. Here, we report five target genes of Hog1p-Sko1p: GRE2, AHP1, SFA1, GLR1 and YML131w. The two CREs in the GRE2 promoter function as activating sequences and, hence, bind (an) activator protein(s). However, the two other yeast CRE-binding proteins, Aca1p and Aca2p, are not involved in regulation of the GRE2 promoter under osmotic stress. In the absence of the co-repressor complex Tup1p-Ssn6p/Cyc8p, which is recruited by Sko1p, stimulation by osmotic stress is still observed. These data indicate that Sko1p is not only required for repression, but also involved in induction upon osmotic shock. All five Sko1p targets encode oxidoreductases with demonstrated or predicted roles in repair of oxidative damage. Altered basal expression levels of these genes in hog1Delta and sko1Delta mutants may explain the oxidative stress phenotypes of these mutants. All five Sko1p target genes are induced by oxidative stress, and induction involves Yap1p. Although Sko1p and Yap1p appear to mediate osmotic and oxidative stress responses independently, Sko1p may affect Yap1p promoter access or activity. The five Sko1p target genes described here are suitable models for studying the interplay between osmotic and oxidative responses at the molecular and physiological levels.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Enzimas/genética , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteínas Repressoras/metabolismo , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Fatores Ativadores da Transcrição , Fatores de Transcrição de Zíper de Leucina Básica , Proteínas de Ligação a DNA/genética , Enzimas/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Glicerol/metabolismo , Proteínas Quinases Ativadas por Mitógeno/genética , Mutação , Concentração Osmolar , Estresse Oxidativo , Oxirredutases/genética , Oxirredutases/metabolismo , Regiões Promotoras Genéticas , Proteínas Repressoras/genética , Elementos de Resposta , Transdução de Sinais , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
14.
Eur J Biochem ; 268(2): 334-43, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11168368

RESUMO

The Saccharomyces cerevisiae strain Sigma1278b possesses two putative aquaporins, Aqy1-1p and Aqy2-1p. Previous work demonstrated that Aqy1-1p functions as a water channel in Xenopus oocyte. However, no function could be attributed to Aqy2-1p in this system. Specific antibodies were used to follow the expression of Aqy1-1p and Aqy2-1p in the yeast. Aqy1-1p was never detected whatever the growth phase and culture conditions tested. In contrast, Aqy2-1p was detected only during the exponential growth phase in rich medium containing glucose. Aqy2-1p expression was repressed by hyper-osmotic culture conditions. Both immunocytochemistry and biochemical subcellular fractionation demonstrated that Aqy2-1p is located on the endoplasmic reticulum (ER) as well as on the plasma membrane. In microsomal vesicles enriched in ER, a water channel activity due to Aqy2-1p was detected by stopped-flow analysis. Our results show that the expression of aquaporins is tightly controlled. The physiological relevance of aquaporin-mediated water transport in yeast is discussed.


Assuntos
Aquaporinas/fisiologia , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/fisiologia , Água/metabolismo , Aquaporinas/isolamento & purificação , Transporte Biológico , Membrana Celular/metabolismo , Retículo Endoplasmático/metabolismo , Análise de Injeção de Fluxo , Proteínas Fúngicas/fisiologia , Regulação Fúngica da Expressão Gênica , Microssomos/metabolismo , Pressão Osmótica , Proteínas Recombinantes
15.
FEMS Yeast Res ; 1(3): 205-11, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12702345

RESUMO

The deletion of the gene encoding the glycerol facilitator Fps1p was associated with an altered plasma membrane lipid composition in Saccharomyces cerevisiae. The S. cerevisiae fps1delta strain respectively contained 18 and 26% less ergosterol than the wild-type strain, at the whole-cell level and at the plasma membrane level. Other mutants with deficiencies in glycerol metabolism were studied to investigate any possible link between membrane ergosterol content and intracellular glycerol accumulation. In these mutants a modification in intracellular glycerol concentration, or in intra- to extracellular glycerol ratio was accompanied by a reduction in plasma membrane ergosterol content. However, there was no direct correlation between ergosterol content and intracellular glycerol concentration. Lipid composition influences the membrane permeability for solutes during adaptation of yeast cells to osmotic stress. In this study, ergosterol supplementation was shown to partially suppress the hypo-osmotic sensitivity phenotype of the fps1delta strain, leading to more efficient glycerol efflux, and improved survival. The erg-1 disruption mutant, which is unable to synthesise ergosterol, survived and recovered from the hypo-osmotic shock more successfully when the concentration of exogenously supplied ergosterol was increased. The results obtained suggest that a higher ergosterol content facilitates the flux of glycerol across the plasma membrane of S. cerevisiae cells.


Assuntos
Membrana Celular/metabolismo , Ergosterol/metabolismo , Deleção de Genes , Glicerol/metabolismo , Proteínas de Membrana/genética , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Transporte Biológico , Permeabilidade da Membrana Celular , Meios de Cultura , Proteínas de Membrana/fisiologia , Pressão Osmótica , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Proteínas de Saccharomyces cerevisiae/fisiologia
16.
J Biol Chem ; 276(5): 3555-63, 2001 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-11058591

RESUMO

We have characterized the strongly homologous GPP1/RHR2 and GPP2/HOR2 genes, encoding isoforms of glycerol 3-phosphatase. Mutants lacking both GPP1 and GPP2 are devoid of glycerol 3-phosphatase activity and produce only a small amount of glycerol, confirming the essential role for this enzyme in glycerol biosynthesis. Overproduction of Gpp1p and Gpp2p did not significantly enhance glycerol production, indicating that glycerol phosphatase is not rate-limiting for glycerol production. Previous studies have shown that expression of both GPP1 and GPP2 is induced under hyperosmotic stress and that induction partially depends on the HOG (high osmolarity glycerol) pathway. We here show that expression of GPP1 is strongly decreased in strains having low protein kinase A activity, although it is still responsive to osmotic stress. The gpp1Delta/gpp2Delta double mutant is hypersensitive to high osmolarity, whereas the single mutants remain unaffected, indicating GPP1 and GPP2 substitute well for each other. Transfer to anaerobic conditions does not affect expression of GPP2, whereas GPP1 is transiently induced, and mutants lacking GPP1 show poor anaerobic growth. All gpp mutants show increased levels of glycerol 3-phosphate, which is especially pronounced when gpp1Delta and gpp1Delta/gpp2Delta mutants are transferred to anaerobic conditions. The addition of acetaldehyde, a strong oxidizer of NADH, leads to decreased glycerol 3-phosphate levels and restored anaerobic growth of the gpp1Delta/gpp2Delta mutant, indicating that the anaerobic accumulation of NADH causes glycerol 3-phosphate to reach growth-inhibiting levels. We also found the gpp1Delta/gpp2Delta mutant is hypersensitive to the superoxide anion generator, paraquat. Consistent with a role for glycerol 3-phosphatase in protection against oxidative stress, expression of GPP2 is induced in the presence of paraquat. This induction was only marginally affected by the general stress-response transcriptional factors Msn2p/4p or protein kinase A activity. We conclude that glycerol metabolism plays multiple roles in yeast adaptation to altered growth conditions, explaining the complex regulation of glycerol biosynthesis genes.


Assuntos
Anaerobiose/fisiologia , Glicerol/metabolismo , Isoenzimas/metabolismo , Estresse Oxidativo/fisiologia , Monoéster Fosfórico Hidrolases/metabolismo , Saccharomyces cerevisiae/enzimologia , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Fermentação , Expressão Gênica , Glicerofosfatos/metabolismo , Isoenzimas/genética , Mutação , Concentração Osmolar , Pressão Osmótica , Monoéster Fosfórico Hidrolases/genética , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/fisiologia
17.
J Biol Chem ; 275(44): 34486-92, 2000 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-10931824

RESUMO

Among a selected group of mouse strains susceptible to dietary obesity, those with an enhanced capacity for Ucp1 and brown adipocyte induction in white fat preferentially lost body weight following adrenergic stimulation. Based on the generality of this mechanism for reducing obesity, a genetic analysis was initiated to identify genes that control brown adipocyte induction in white fat depots in mice. Quantitative trait locus (QTL) analysis was performed using the variations of retroperitoneal fat Ucp1 mRNA expression in progeny of genetic crosses between the A/J and C57BL/6J parental strains and selected AXB recombinant inbred strains. Three A/J-derived loci on chromosomes 2, 3, and 8 and one C57BL/6J locus on chromosome 19 were linked to Ucp1 induction in retroperitoneal fat. Although A/J-derived alleles seemed to contribute to elevated Ucp1 expression, the C57BL/6J allele on chromosome 19 increased Ucp1 mRNA to levels higher than parental values. Thus, novel patterns of C57BL/6J and A/J recombinant genotypes among the four mapped loci resulted in a transgressive variation of Ucp1 phenotypes. Although the extent of the interchromosomal interactions have not been fully explored, strong synergistic interactions occur between a C57BL/6J allele on chromosome 19 and an A/J allele on chromosome 8. In addition to selective synergistic interactions between loci, variations in recessive and dominant effects also contribute to the final levels of Ucp1 expression.


Assuntos
Tecido Adiposo/metabolismo , Proteínas de Transporte/genética , Regulação da Expressão Gênica , Proteínas de Membrana/genética , Animais , Sequência de Bases , Mapeamento Cromossômico , Cruzamentos Genéticos , Primers do DNA , Variação Genética , Canais Iônicos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Mitocondriais , Característica Quantitativa Herdável , Proteína Desacopladora 1
18.
J Clin Microbiol ; 38(8): 3076-9, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10921981

RESUMO

The Alexon-Trend, Inc. (Ramsey, Minn.), ProSpecT Campylobacter microplate assay was compared with culture on a Campy-CVA plate (Remel, Lenexa, Kans.) and blood-free campylobacter agar with cefoperazone (20 microg/ml), amphotericin B (10 microg/ml), and teicoplanin (4 microg/ml) (CAT medium; Oxoid Limited, Hampshire, England) with 631 patient stool samples. The CAT medium was used to isolate Campylobacter upsaliensis. The enzyme immunoassay (EIA) had a sensitivity and a specificity of 89 and 99%, respectively, and the positive and negative predictive values were 80 and 99%, respectively. Even though we extensively looked for C. upsaliensis in stool samples from patients from the greater Salt Lake City area, we did not isolate this species during the study period. The overall excellent specificity of the EIA allows rapid detection and treatment of positive patients; however, a negative result should be confirmed by culture when clinical suspicion is high.


Assuntos
Infecções por Campylobacter/epidemiologia , Campylobacter jejuni/isolamento & purificação , Campylobacter/isolamento & purificação , Fezes/microbiologia , Técnicas Imunoenzimáticas , Infecções por Campylobacter/microbiologia , Campylobacter jejuni/crescimento & desenvolvimento , Meios de Cultura , Humanos , Vigilância da População , Valor Preditivo dos Testes , Sensibilidade e Especificidade , Utah/epidemiologia
19.
Yeast ; 16(10): 897-903, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10870101

RESUMO

Aquaporin water channels facilitate the transmembrane diffusion of water and higher organisms possess a large number of isoforms. The genome of the yeast Saccharomyces cerevisiae contains two highly similar aquaporin genes, AQY1 and AQY2. AQY1 has been shown to encode a functional water channel but only in certain laboratory strains. Here we show that the AQY2 gene is interrupted by an 11 bp deletion in 23 of the 27 laboratory strains tested, with the exception of strains from the sigma 1278b background, which also exhibit a functional Aqy1p. However, although the AQY2 gene from sigma 1278b is highly homologous to functional aquaporins, we did not observe Aqy2p-mediated water transport in Xenopus oocytes. A survey of 52 yeast strains revealed that all industrial and wild yeasts carry the allele encoding a functional Aqy1p, while none of these strains appear to have a functional Aqy2p. We conclude that natural and industrial conditions provide selective pressure to maintain AQY1 but apparently not AQY2.


Assuntos
Aquaporinas/genética , Polimorfismo Genético , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Sequência de Aminoácidos , Aquaporinas/química , Aquaporinas/metabolismo , Sequência de Bases , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Dados de Sequência Molecular , Mapeamento por Restrição , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Alinhamento de Sequência , Análise de Sequência de DNA
20.
Yeast ; 16(7): 589-96, 2000 May.
Artigo em Inglês | MEDLINE | ID: mdl-10806421

RESUMO

The Saccharomyces cerevisiae TIM10 gene encodes one of the few essential mitochondrial proteins that are required for the import of nuclear-encoded precursor proteins from the cytosol and their subsequent sorting into the different mitochondrial compartments. We have isolated and characterized a putative homologue of TIM10 from the halotolerant yeast Pichia sorbitophila. The Pichia TIM10 gene encodes a protein of 90 amino acids with 66% identity to S. cerevisiae Tim10p. It was capable of suppressing the temperature sensitivity of tim10-1 mutant in S. cerevisiae, suggesting that Pichia TIM10 is both a functional and structural homologue of S. cerevisiae TIM10. The putative Pichia TIM10 gene product contains all the four conserved cysteine residues and the two CX(3)C motifs typical of the Tim family proteins in the mitochondrial intermembrane space. Using anti-Tim10p serum, Western blots detected a protein of about 10 kDa, suggesting that the Pichia Tim10p is a mitochondrial protein. The results suggest that mitochondrial import and sorting systems might be also strongly conserved in other fungi. The coding sequence of the P. sorbitophila TIM10 has been deposited in the EMBL Nucleotide Sequence Database under Accession No. AJ243940.


Assuntos
Proteínas Fúngicas/isolamento & purificação , Proteínas Fúngicas/metabolismo , Mitocôndrias/metabolismo , Pichia/metabolismo , Proteínas de Saccharomyces cerevisiae , Sequência de Aminoácidos , Sequência de Bases , Western Blotting , Reações Cruzadas , Proteínas Fúngicas/genética , Proteínas Fúngicas/imunologia , Genes Fúngicos , Teste de Complementação Genética , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Proteínas do Complexo de Importação de Proteína Precursora Mitocondrial , Dados de Sequência Molecular , Filogenia , Pichia/genética , Pichia/crescimento & desenvolvimento , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Análise de Sequência de DNA
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...