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1.
J Surg Oncol ; 2024 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-38845213

RESUMO

BACKGROUND: Locally advanced triple-negative breast cancer (TNBC) represents a public health problem in Brazil. Its standard treatment consists of neoadjuvant chemotherapy (NAC). METHODS: This was a longitudinal study with follow-up performed between the years 2015 and 2017. Thirty women with locally advanced TNBC submitted to NAC, and 30 healthy were included. Peripheral blood samples were collected before NAC (Pre-NAC) and after NAC (Post-NAC). RESULTS: Patients with TNBC had elevated levels of CD28+ T, FAS+ T, CTLA4+ T, PD1+ T, CD28+CD4+ T, PD1+CD4+ T and CD8+ T and PD1+ CD8+ T cells compared to controls (p < 0.05). Patients with pathological complete response (pCR) had low FAS+ T cells, FAS+CD4+ T cells, and PD1+CD8+ T cells compared to the non-pCR (p < 0.05). Significant differences were observed in the levels of CD28+ T cells, FAS+ T and PD1+ T, CD4+ T, CD28+CD4+ T, FAS+CD4+ T, PD1+CD4+ T, CD8+ T, and PD1+CD8+ T cells between Pre-NAC and Post-NAC groups (p < 0.05). CONCLUSION: Alterations in the circulating FAS+CD4+ T and PD1+CD8+ T cell levels Pre-NAC are associated with pCR, suggesting potential predictive biomarkers of NAC response in TNBC. The largest changes in the cellular immune response profile Post-NAC showed that chemotherapy treatment can modulate the immune response and that it is associated with prognosis in TNBC.

2.
Blood ; 138(15): 1345-1358, 2021 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-34010414

RESUMO

The blood system serves as a key model for cell differentiation and cancer. It is orchestrated by precise spatiotemporal expression of crucial transcription factors. One of the key master regulators in the hematopoietic systems is PU.1. Reduced levels of PU.1 are characteristic for human acute myeloid leukemia (AML) and are known to induce AML in mouse models. Here, we show that transcriptional downregulation of PU.1 is an active process involving an alternative promoter in intron 3 that is induced by RUNX transcription factors driving noncoding antisense transcription. Core-binding factor (CBF) fusions RUNX1-ETO and CBFß-MYH11 in t(8;21) and inv(16) AML, respectively, activate the PU.1 antisense promoter that results in a shift from sense toward antisense transcription and myeloid differentiation blockade. In patients with CBF-AML, we found that an elevated antisense/sense transcript and promoter accessibility ratio represents a hallmark compared with normal karyotype AML or healthy CD34+ cells. Competitive interaction of an enhancer with the proximal or the antisense promoter forms a binary on/off switch for either myeloid or T-cell development. Leukemic CBF fusions thus use a physiological mechanism used by T cells to decrease sense transcription. Our study is the first example of a sense/antisense promoter competition as a crucial functional switch for gene expression perturbation by oncogenes. Hence, this disease mechanism reveals a previously unknown Achilles heel for future precise therapeutic targeting of oncogene-induced chromatin remodeling.


Assuntos
Subunidade alfa 2 de Fator de Ligação ao Core/genética , Subunidade beta de Fator de Ligação ao Core/genética , Regulação Leucêmica da Expressão Gênica , Leucemia Mieloide Aguda/genética , Proteínas Proto-Oncogênicas/genética , Transativadores/genética , Elementos Antissenso (Genética)/genética , Linhagem Celular Tumoral , Fusão Gênica , Humanos , Proteínas de Fusão Oncogênica/genética , Regiões Promotoras Genéticas , Proteína 1 Parceira de Translocação de RUNX1/genética , Células Tumorais Cultivadas
3.
Am J Physiol Heart Circ Physiol ; 319(3): H642-H650, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32762556

RESUMO

The right ventricle (RV) is often overlooked in the evaluation of cardiac performance and treatment of left ventricular (LV) heart diseases. However, recent evidence suggests the RV may play an important role in maintaining systemic cardiac function and delivering stroke volume (SV). We used exercise cardiac magnetic resonance and biomechanical modeling to investigate the role of the RV in LV stroke volume regulation. We studied SV augmentation during exercise by pharmacologically inducing negative chronotropy (sHRi) in healthy volunteers and investigating training-induced SV augmentation in endurance athletes. SV augmentation during exercise after sHRi is achieved differently in the two ventricles. In the RV, the larger SV is driven by increasing contraction down to lower end-systolic volume (ESV; P < 0.001). In the LV, SV augmentation is achieved through an increase in end-diastolic volume (EDV; P < 0.001), avoiding contraction to a lower ESV. The same mechanism underlies the enhanced SV response observed in athletes. Changes in atrial area during SV augmentation suggest that the improved LV EDV response is sustained by the larger RV contractions. Using our biomechanical model, we explain this behavior by showing that the RV systolic function-driven regulation of LV SV optimizes the energetic cost of LV contraction and leads to minimization of the total costs of biventricular contraction. In conclusion, this work provides mechanistic understanding of the pivotal role of the RV in optimizing LV SV during exercise. It demonstrates why optimizing RV function needs to become a key part of therapeutic strategies in patients and training for athletes.NEW & NOTEWORTHY The right ventricle appears to have an important impact on maintaining systemic cardiac function and delivering stroke volume. However, its exact role in supporting left ventricular function has so far been unclear. This study demonstrates a new mechanism of ventricular interaction that provides mechanistic understanding of the key importance of the right ventricle in driving cardiac performance.


Assuntos
Exercício Físico , Coração/fisiologia , Volume Sistólico , Função Ventricular Esquerda , Função Ventricular Direita , Adulto , Ciclismo , Fenômenos Biomecânicos , Feminino , Coração/diagnóstico por imagem , Frequência Cardíaca , Humanos , Imageamento por Ressonância Magnética , Masculino , Sístole , Adulto Jovem
4.
Environ Sci Technol ; 52(15): 8488-8500, 2018 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-29979581

RESUMO

Traces of particulate radioactive iodine (131I) were detected in the European atmosphere in January/February 2017. Concentrations of this nuclear fission product were very low, ranging 0.1 to 10 µBq m-3 except at one location in western Russia where they reached up to several mBq m-3. Detections have been reported continuously over an 8-week period by about 30 monitoring stations. We examine possible emission source apportionments and rank them considering their expected contribution in terms of orders of magnitude from typical routine releases: radiopharmaceutical production units > sewage sludge incinerators > nuclear power plants > spontaneous fission of uranium in soil. Inverse modeling simulations indicate that the widespread detections of 131I resulted from the combination of multiple source releases. Among them, those from radiopharmaceutical production units remain the most likely. One of them is located in Western Russia and its estimated source term complies with authorized limits. Other existing sources related to 131I use (medical purposes or sewage sludge incineration) can explain detections on a rather local scale. As an enhancing factor, the prevailing wintertime meteorological situations marked by strong temperature inversions led to poor dispersion conditions that resulted in higher concentrations exceeding usual detection limits in use within the informal Ring of Five (Ro5) monitoring network.


Assuntos
Poluentes Radioativos do Ar , Neoplasias da Glândula Tireoide , Europa (Continente) , Humanos , Radioisótopos do Iodo , Federação Russa
5.
Psychol Trauma ; 2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38512168

RESUMO

OBJECTIVE: This study aimed to assess the relationship between childhood maltreatment (CM), objective and subjective cognition, and psychosocial functioning in adults with first-episode psychosis (FEP) by examining the moderating role of cognitive reserve (CR). A secondary objective was to explore whether unique CM subtypes (physical and/or emotional abuse, sexual abuse, physical and/or emotional neglect) were driving this relationship. METHOD: Sixty-six individuals with FEP (Mage = 27.3, SD = 7.2 years, 47% male) completed a comprehensive neuropsychological test battery, the Cognitive Complaints in Bipolar Disorder Rating Assessment (COBRA), the Functioning Assessment Short Test (FAST), the Childhood Trauma Questionnaire (CTQ), and the Cognitive Reserve Assessment Scale in Health (CRASH). Linear regression analyses were conducted to evaluate the interaction effect of CR between CM and cognitive and psychosocial variables, controlling for age, sex, and social desirability (CTQ-denial-minimization). RESULTS: In adults with FEP overall CM interacted with CR to predict COBRA-subjective cognitive complaints, but not neurocognitive or psychosocial functioning. Sexual abuse and physical neglect interacted with CR to predict verbal memory. Most of the CM subtypes interacted with CR to predict FAST-leisure time, whereas only emotional neglect interacted with CR to predict FAST-interpersonal relationships. Overall, greater CR was related to better functioning. CONCLUSIONS: The current results indicate that associations between specific CM subtypes, subjective and objective cognition, and psychosocial domains are moderated through CR with greater functioning. Early interventions focused on CR seeking to improve cognitive and psychosocial outcomes, with emphasis on improving subjective cognitive functions would be beneficial for individuals with FEP and CM. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

6.
J Radiol Prot ; 33(4): 809-22, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24047590

RESUMO

Considerable levels of radium were detected in a certain fraction of the Estonian drinking water supply network. Some of these waterworks have treatment systems for the removal of (mainly) iron and manganese from drinking water. Three of these waterworks and another one equipped with a radium removal pilot plant were examined, and a specific study was conducted in order to assess the environmental compatibility of effluents and residues produced in the plants. (226)Ra and (228)Ra activity concentrations were analysed in both liquid (backwash water) and solid (sand filter and sediment) materials to evaluate their compliance, from the radiological point of view, with current Estonian legislation and international technical documents that propose reference levels for radium in effluents and residues. Also with regard to water treatment by-products, a preliminary analysis was done of possible consequences of the transposition of the European Basic Safety Standards Draft into Estonian law. Radium removal efficiency was also tested in the same plants. Iron and manganese treatment plants turned out to be scarcely effective, whilst the radium mitigation pilot plant showed a promising performance.


Assuntos
Rádio (Elemento)/isolamento & purificação , Águas Residuárias/análise , Águas Residuárias/química , Poluentes Químicos da Água/isolamento & purificação , Poluentes Radioativos da Água/isolamento & purificação , Purificação da Água/métodos , Abastecimento de Água/análise , Estônia , Rádio (Elemento)/química , Poluentes Químicos da Água/química , Poluentes Radioativos da Água/química
7.
Appl Radiat Isot ; 194: 110675, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36706517

RESUMO

The results of a European intercomparison on 222Rn in water were analyzed to evaluate the performances of standard and non-standard methods. Then, results obtained with a specific LSC method (ISO 13164-4) based on two-phase liquid scintillation counting which has been employed by a considerable number of participants were examined in detail. This ISO LSC method was proved to be accurate, reliable and its reproducibility has been also sufficient. The intercomparison could be used as a collaborative study and the analysis of its results allowed to estimate the method reproducibility.

8.
Eur J Clin Microbiol Infect Dis ; 31(3): 243-50, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21647616

RESUMO

Respiratory syncytial virus (RSV) is the viral agent which is more frequently involved in lower respiratory tract infections (LRTIs) in infants under 1 year of age in developed countries. A new oligochromatographic assay, Speed-Oligo® RSV, was designed and optimized for the specific detection and identification of RSV subtypes A and B. The test was evaluated in 289 clinical samples from 169 hospitalized children using an immunochromatography (IC) test, virus isolation by culture, and an in-house real-time polymerase chain reaction (RT-PCR). Other viruses causing LRTIs were investigated by cell culture or PCR-based tests. Sixty-two patients were infected by RSV (36.7%). In addition, adenovirus, influenza B, parainfluenza 2, and human metapneumovirus were detected in rates ranging from 5 to 8%. A proportion of 10.1% of the patients had mixed infections. The sensitivity, specificity, and positive and negative predictive values were, respectively, 94.9, 99.4, 98.9, and 97.4% for Speed-Oligo® RSV, 92.9, 96.3, 92.9, and 96.3% for RT-PCR/RSV, and 58.4, 98.1, 93.3, and 82.6% for IC. Our rates of viral detection and co-infection were similar to those of previously reported series. Finally, we find that Speed-Oligo® RSV is a rapid and easy-to-perform technique for the detection of RSV and the identification of subtypes A and B.


Assuntos
Bronquiolite Viral/diagnóstico , Infecções por Vírus Respiratório Sincicial/diagnóstico , Vírus Sincicial Respiratório Humano/genética , Adolescente , Bronquiolite Viral/virologia , Criança , Criança Hospitalizada , Pré-Escolar , Técnicas de Diagnóstico do Sistema Respiratório , Hospitalização , Humanos , Lactente , Recém-Nascido , Reação em Cadeia da Polimerase/métodos , Valor Preditivo dos Testes , RNA Viral/análise , RNA Viral/genética , Infecções por Vírus Respiratório Sincicial/virologia , Vírus Sincicial Respiratório Humano/isolamento & purificação , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Sensibilidade e Especificidade
9.
Br J Nutr ; 105(12): 1718-23, 2011 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-21294933

RESUMO

Moderate wine consumption has been shown to lower cardiovascular risk. One of the mechanisms could involve the control of postprandial hyperlipaemia, a well-defined risk factor for atherosclerosis, reasonably by reducing the absorption of lipid oxidised species from the meal. The objective of the present study was to investigate whether wine consumption with the meal is able to reduce the postprandial increase in plasma lipid hydroperoxides and cholesterol oxidation products, in human subjects. In two different study sessions, twelve healthy volunteers consumed the same test meal rich in oxidised and oxidisable lipids (a double cheeseburger), with 300 ml of water (control) or with 300 ml of red wine (wine). The postprandial plasma concentration of cholesterol oxidation products was measured by GC-MS. The control meal induced a significant increase in the plasma concentration of lipid hydroperoxides and of two cholesterol oxidation products, 7-ß-hydroxycholesterol and 7-ketocholesterol. The postprandial increase in lipid hydroperoxides and cholesterol oxidation products was fully prevented by wine when consumed with the meal. In conclusion, the present study provides evidence that consumption of wine with the meal could prevent the postprandial increase in plasma cholesterol oxidation products.


Assuntos
Colesterol/sangue , Peróxidos Lipídicos/sangue , Estresse Oxidativo/fisiologia , Polifenóis/análise , Período Pós-Prandial/fisiologia , Vinho , Adulto , Análise de Variância , Colesterol/metabolismo , Estudos Cross-Over , Feminino , Humanos , Masculino , Projetos Piloto
10.
J Radiol Prot ; 30(4): 761-80, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21149943

RESUMO

In some areas of Estonia, groundwater contains a significant number of natural radionuclides, especially radium isotopes, which may cause radiation protection concern depending on the geological structure of the aquifer. Indeed, the parametric value of 0.1 mSv y⁻¹ for the total indicative dose established by European Directive 98/83/EC, adopted as a limit value in Estonian national legislation, is often exceeded. A Twinning Project between Estonia and Italy was carried out within the framework of the Estonian Transition Facility Programme, sponsored by the European Union. Its aims were to assess the radiological situation of Estonian groundwater and related health consequences. The first step was a study of Estonian aqueducts and the population served by them, and a thorough analysis of the radiological database for drinking water, from which the relevant effective doses for the population were obtained. Particular attention was devoted to doses to children and infants. Correlations between the chemical parameters were investigated, in order to suggest the best possible analytical approach. Lastly, a monitoring strategy, i.e. sampling points and sampling frequencies, was proposed.


Assuntos
Monitoramento de Radiação/métodos , Rádio (Elemento)/análise , Poluentes Radioativos da Água/análise , Abastecimento de Água/análise , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Estônia , Humanos , Lactente , Pessoa de Meia-Idade , Doses de Radiação
11.
J Cell Biol ; 92(2): 559-64, 1982 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-7061597

RESUMO

Mutants in Paramecium tetraurelia, unable to generate action potentials, have been isolated as cells which show no backward swimming in response to ionic stimulation. These "pawn" mutants belong to at least three complementation groups designated pwA, pwB, and pwC. We have found that microinjection of cytoplasm from a wild-type donor into a pawn recipient of any of the three complementation groups restores the ability of the pawn to generate action potentials and hence swim backward. In addition, the cytoplasm from a pawn cannot restore a recipient of the same complementation group, but that from a pawn of a different group can. Electrophysiological analysis had demonstrated that the restoration of backward swimming is not due to a simple addition of ions but represents a profound change in the excitable membrane of the recipient pawn cells. Using known pawn mutants and those which had previously been unclassified, we have been able to establish a perfect concordance of genetic complementation and complementation by cytoplasmic transfer through microinjection. This method has been used to classify pawn mutants that are sterile or hard-to-mate and to examine the ability of cytoplasms from different species of ciliated protozoa to restore the ability to swim backward in the pawn mutants of P. tetraurelia. A cell homogenate has also been fractionated by centrifugation to further purify the active components. These results demonstrate that transfer of cytoplasm between cells by microinjection can be a valid and systematic method to classify mutants. This test is simpler to perform than the genetic complementation test and can be used under favorable conditions in mutants that are sterile and in cells of different species.


Assuntos
Paramecium/genética , Potenciais de Ação , Animais , Cílios/fisiologia , Citoplasma/fisiologia , Teste de Complementação Genética/métodos , Locomoção , Potenciais da Membrana , Microinjeções , Mutação , Paramecium/fisiologia
12.
J Cell Biol ; 152(2): 289-300, 2001 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-11266446

RESUMO

Porin, also termed the voltage-dependent anion channel, is the most abundant protein of the mitochondrial outer membrane. The process of import and assembly of the protein is known to be dependent on the surface receptor Tom20, but the requirement for other mitochondrial proteins remains controversial. We have used mitochondria from Neurospora crassa and Saccharomyces cerevisiae to analyze the import pathway of porin. Import of porin into isolated mitochondria in which the outer membrane has been opened is inhibited despite similar levels of Tom20 as in intact mitochondria. A matrix-destined precursor and the porin precursor compete for the same translocation sites in both normal mitochondria and mitochondria whose surface receptors have been removed, suggesting that both precursors utilize the general import pore. Using an assay established to monitor the assembly of in vitro-imported porin into preexisting porin complexes we have shown that besides Tom20, the biogenesis of porin depends on the central receptor Tom22, as well as Tom5 and Tom7 of the general import pore complex (translocase of the outer mitochondrial membrane [TOM] core complex). The characterization of two new mutant alleles of the essential pore protein Tom40 demonstrates that the import of porin also requires a functional Tom40. Moreover, the porin precursor can be cross-linked to Tom20, Tom22, and Tom40 on its import pathway. We conclude that import of porin does not proceed through the action of Tom20 alone, but requires an intact outer membrane and involves at least four more subunits of the TOM machinery, including the general import pore.


Assuntos
Membranas Intracelulares/fisiologia , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Proteínas de Membrana Transportadoras , Mitocôndrias/fisiologia , Porinas/biossíntese , Receptores de Superfície Celular , Receptores Citoplasmáticos e Nucleares , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/fisiologia , Sequência de Aminoácidos , Substituição de Aminoácidos , Genótipo , Membranas Intracelulares/ultraestrutura , Cinética , Proteínas de Membrana/química , Mitocôndrias/ultraestrutura , Proteínas de Transporte da Membrana Mitocondrial , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Neurospora crassa/genética , Neurospora crassa/fisiologia , Neurospora crassa/ultraestrutura , Porinas/metabolismo , Transporte Proteico , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/ultraestrutura , Canais de Ânion Dependentes de Voltagem
13.
Science ; 247(4947): 1233-6, 1990 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-1690454

RESUMO

The gene encoding the yeast mitochondrial outer membrane channel VDAC was subjected to site-directed mutagenesis to change amino acids at 29 positions to residues differing in charge from the wild-type sequence. The mutant genes were then expressed in yeast, and the physiological consequences of single and multiple amino acid changes were assessed after isolation and insertion of mutant channels into phospholipid bilayers. Selectivity changes were observed at 14 sites distributed throughout the length of the molecule. These sites are likely to define the position of the protein walls lining the aqueous pore and hence, the transmembrane segments. These results have been used to develop a model of the open state of the channel in which each polypeptide contributes 12 beta strands and one alpha helix to form the aqueous transmembrane pathway.


Assuntos
Canais Iônicos , Proteínas de Membrana/genética , Mutação , Porinas , Saccharomyces cerevisiae/genética , Sequência de Aminoácidos , Clonagem Molecular , Membranas Intracelulares/fisiologia , Bicamadas Lipídicas/metabolismo , Potenciais da Membrana , Proteínas de Membrana/fisiologia , Mitocôndrias/ultraestrutura , Dados de Sequência Molecular , Conformação Proteica , Saccharomyces cerevisiae/ultraestrutura , Relação Estrutura-Atividade , Canais de Ânion Dependentes de Voltagem
14.
Science ; 225(4660): 427-8, 1984 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-6330895

RESUMO

Two different divalent cation-selective channels from Paramecium cilia were incorporated into planar lipid bilayers. Both channels were much more permeable to divalent than univalent cations, and one of them discriminated significantly among the divalent cations. The selectivity and voltage dependence of the latter channel are comparable to those of voltage-dependent calcium channels found in a variety of cells. A combined biochemical, biophysical, and genetic study of calcium channels is now possible.


Assuntos
Cálcio/metabolismo , Cílios/metabolismo , Canais Iônicos/metabolismo , Bicamadas Lipídicas/metabolismo , Paramecium/metabolismo , Bário/metabolismo , Cloretos/metabolismo , Eletrofisiologia , Canais Iônicos/fisiologia , Magnésio/metabolismo , Potássio/metabolismo
15.
Science ; 274(5295): 2104-7, 1996 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-8953046

RESUMO

Disruptions in mushroom body (MB) or central complex (CC) brain structures impair Drosophila associative olfactory learning. Perturbations in adenosine 3',5' monophosphate signaling also disrupt learning. To integrate these observations, expression of a constitutively activated stimulatory heterotrimeric guanosine triphosphate-binding protein alpha subunit (Galphas*) was targeted to these brain structures. The ability to associate odors with electroshock was abolished when Galphas* was targeted to MB, but not CC, structures, whereas sensorimotor responses to these stimuli remained normal. Expression of Galphas* did not affect gross MB morphology, and wild-type Galphas expression did not affect learning. Thus, olfactory learning depends on regulated Gs signaling in Drosophila MBs.


Assuntos
Condicionamento Psicológico , Drosophila/metabolismo , Subunidades alfa Gs de Proteínas de Ligação ao GTP/metabolismo , Neurônios/metabolismo , Transdução de Sinais , Adenilil Ciclases/metabolismo , Animais , Encéfalo/anatomia & histologia , Encéfalo/metabolismo , Eletrochoque , Subunidades alfa Gs de Proteínas de Ligação ao GTP/genética , Guanosina Trifosfato/metabolismo , Odorantes , Olfato/fisiologia , Transgenes
16.
Trends Biochem Sci ; 26(2): 112-7, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11166569

RESUMO

The role of mitochondria as crucial participants in cell death programs is well established, yet the mechanisms responsible for the release of mitochondrial activators and the role of BCL2 family proteins in this process remain controversial. Here, we point out the limitations of current approaches used to monitor the physiological responses of mitochondria during cell death, the implications arising from modern views of mitochondrial structure, and briefly assess two proposed mechanisms for the release of mitochondrial proteins during apoptosis.


Assuntos
Apoptose , Morte Celular , Mitocôndrias/metabolismo , Animais , Membrana Celular/metabolismo , Ciclosporina/farmacologia , Resistência a Múltiplos Medicamentos , Inibidores Enzimáticos/farmacologia , Modelos Biológicos , Estrutura Terciária de Proteína , Proteínas Proto-Oncogênicas c-bcl-2/fisiologia
17.
Neuroscience ; 155(3): 585-96, 2008 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-18621101

RESUMO

In this report, we have assessed the behavioral responses of mice missing the Ppif gene (CyPD-KO), encoding mitochondrial cyclophilin D (CyPD). Mitochondrial CyPD is a key modulator of the mitochondrial permeability transition which is involved in the regulation of calcium- and oxidative damage-induced cell death. Behavioral screening of CyPD-KO mice (ranging between 4 and 15 months of age) was accomplished using a battery of behavioral paradigms which included testing of motor functions, exploratory activity, and anxiety/emotionality, as well as learning and memory skills. We found that, compared with wild-type mice, CyPD-KO mice were (i) more anxious and less explorative in open field and elevated plus maze and (ii) performed better in learning and memory of avoidance tasks, such as active and passive avoidance. However, the absence of CyPD did not alter the nociceptive threshold for thermal stimuli. Finally, deletion of CyPD caused also an abnormal accumulation of white adipose tissue resulting in adult-onset obesity, which was not dependent on increased food and/or water intake. Taken together, our results suggest a new fundamental role of mitochondrial CyPD in basal brain functions and body weight homeostasis.


Assuntos
Ansiedade/genética , Ansiedade/fisiopatologia , Aprendizagem da Esquiva/fisiologia , Ciclofilinas/deficiência , Obesidade/genética , Obesidade/fisiopatologia , Fatores Etários , Análise de Variância , Animais , Comportamento Animal , Peso Corporal/genética , Peptidil-Prolil Isomerase F , Modelos Animais de Doenças , Ingestão de Líquidos/genética , Ingestão de Alimentos/genética , Comportamento Exploratório/fisiologia , Masculino , Aprendizagem em Labirinto/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Atividade Motora/fisiologia , Limiar da Dor/fisiologia , Desempenho Psicomotor/fisiologia
18.
Curr Biol ; 10(4): 211-4, 2000 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-10704417

RESUMO

Sensitization to repeated doses of psychostimulants is thought to be an important component underlying the addictive process in humans [1] [2] [3] [4]. In all vertebrate animal models, including humans [5], and even in fruit flies, sensitization is observed after repeated exposure to volatilized crack cocaine [6]. In vertebrates, sensitization is thought to be initiated by processes occurring in brain regions that contain dopamine cell bodies [2] [7]. Here, we show that modulated cell signaling in the Drosophila dopamine and serotonin neurons plays an essential role in cocaine sensitization. Targeted expression of either a stimulatory (Galpha(s)) or inhibitory (Galpha(i)) Galpha subunit, or tetanus toxin light chain (TNT) in dopamine and serotonin neurons of living flies blocked behavioral sensitization to repeated cocaine exposures. These flies showed alterations in their initial cocaine responsiveness that correlated with compensatory adaptations of postsynaptic receptor sensitivity. Finally, repeated drug stimulation of a nerve cord preparation that is postsynaptic to the brain amine cells failed to induce sensitization, further showing the importance of presynaptic modulation in sensitization.


Assuntos
Cocaína/farmacologia , Dopamina/metabolismo , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/metabolismo , Subunidades alfa Gs de Proteínas de Ligação ao GTP/metabolismo , Neurônios/metabolismo , Serotonina/metabolismo , Animais , Drosophila melanogaster , Tolerância a Medicamentos , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/genética , Subunidades alfa Gs de Proteínas de Ligação ao GTP/genética , Neurônios/efeitos dos fármacos , Sinapses/fisiologia , Toxina Tetânica/metabolismo , Toxina Tetânica/farmacologia
19.
Mol Cell Biol ; 10(3): 910-7, 1990 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-2106072

RESUMO

G proteins are responsible for modulating the activity of intracellular effector systems in response to receptor activation. The stimulatory G protein Gs is responsible for activation of adenylate cyclase in response to a variety of hormonal signals. In this report, we describe the structure of the gene for the alpha subunit of Drosophila melanogaster Gs. The gene is approximately 4.5 kilobases long and is divided into nine exons. The exon-intron structure of the Drosophila gene shows substantial similarity to that of the human gene for Gs alpha. Alternate splicing of intron 7, involving either use of an unusual TG or consensus AG 3' splice site, results in transcripts which code for either a long (DGs alpha L) or short (DGs alpha S) form of Gs alpha. These subunits differ by inclusion or deletion of three amino acids and substitution of a Ser for a Gly. The two forms of Drosophila Gs alpha differ in a region where no variation in the primary sequence of vertebrate Gs alpha subunits has been observed. In vitro translation experiments demonstrated that the Drosophila subunits migrate anomalously on sodium dodecyl sulfate-polyacrylamide gels with apparent molecular weights of 51,000 and 48,000. Additional Gs alpha transcript heterogeneity reflects the use of multiple polyadenylation sites.


Assuntos
Drosophila melanogaster/genética , Proteínas de Ligação ao GTP/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Clonagem Molecular , Genes , Dados de Sequência Molecular , Peso Molecular , Poli A/metabolismo , Biossíntese de Proteínas , Splicing de RNA , Mapeamento por Restrição
20.
Mol Cell Biol ; 17(10): 5727-38, 1997 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9315631

RESUMO

The permeability of the outer mitochondrial membrane to most metabolites is believed to be based in an outer membrane, channel-forming protein known as VDAC (voltage-dependent anion channel). Although multiple isoforms of VDAC have been identified in multicellular organisms, the yeast Saccharomyces cerevisiae has been thought to contain a single VDAC gene, designated POR1. However, cells missing the POR1 gene (delta por1) were able to grow on yeast media containing a nonfermentable carbon source (glycerol) but not on such media at elevated temperature (37 degrees C). If VDAC normally provides the pathway for metabolites to pass through the outer membrane, some other protein(s) must be able to partially substitute for that function. To identify proteins that could functionally substitute for POR1, we have screened a yeast genomic library for genes which, when overexpressed, can correct the growth defect of delta por1 yeast grown on glycerol at 37 degrees C. This screen identified a second yeast VDAC gene, POR2, encoding a protein (YVDAC2) with 49% amino acid sequence identity to the previously identified yeast VDAC protein (YVDAC1). YVDAC2 can functionally complement defects present in delta por1 strains only when it is overexpressed. Deletion of the POR2 gene alone had no detectable phenotype, while yeasts with deletions of both the POR1 and POR2 genes were viable and able to grow on glycerol at 30 degrees C, albeit more slowly than delta por1 single mutants. Like delta por1 single mutants, they could not grow on glycerol at 37 degrees C. Subcellular fractionation studies with antibodies which distinguish YVDAC1 and YVDAC2 indicate that YVDAC2 is normally present in the outer mitochondrial membrane. However, no YVDAC2 channels were detected electrophysiologically in reconstituted systems. Therefore, mitochondrial membranes made from wild-type cells, delta por1 cells, delta por1 delta por2 cells, and delta por1 cells overexpressing YVDAC2 were incorporated into liposomes and the permeability of resulting liposomes to nonelectrolytes of different sizes was determined. The results indicate that YVDAC2 does not confer any additional permeability to these liposomes, suggesting that it may not normally form a channel. In contrast, when the VDAC gene from Drosophila melanogaster was expressed in delta por1 yeast cells, VDAC-like channels could be detected in the mitochondria by both bilayer and liposome techniques, yet the cells failed to grow on glycerol at 37 degrees C. Thus, channel-forming activity does not seem to be either necessary or sufficient to restore growth on nonfermentable carbon sources, indicating that VDAC mediates cellular functions that do not depend on the ability to form channels.


Assuntos
Genes Fúngicos/fisiologia , Proteínas de Membrana/genética , Porinas , Saccharomyces cerevisiae/genética , Sequência de Aminoácidos , Clonagem Molecular , Proteínas de Drosophila , Condutividade Elétrica , Teste de Complementação Genética , Glicerol , Membranas Intracelulares/química , Lipossomos , Proteínas de Membrana/análise , Proteínas de Membrana/fisiologia , Mitocôndrias/química , Dados de Sequência Molecular , Fenótipo , Saccharomyces cerevisiae/crescimento & desenvolvimento , Homologia de Sequência de Aminoácidos , Supressão Genética , Temperatura , Canais de Ânion Dependentes de Voltagem
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