RESUMO
We report a search for time variations of the solar ^{8}B neutrino flux using 5804 live days of Super-Kamiokande data collected between May 31, 1996, and May 30, 2018. Super-Kamiokande measured the precise time of each solar neutrino interaction over 22 calendar years to search for solar neutrino flux modulations with unprecedented precision. Periodic modulations are searched for in a dataset comprising five-day interval solar neutrino flux measurements with a maximum likelihood method. We also applied the Lomb-Scargle method to this dataset to compare it with previous reports. The only significant modulation found is due to the elliptic orbit of the Earth around the Sun. The observed modulation is consistent with astronomical data: we measured an eccentricity of (1.53±0.35)%, and a perihelion shift of (-1.5±13.5) days.
RESUMO
We report a search for cosmic-ray boosted dark matter with protons using the 0.37 megaton×years data collected at Super-Kamiokande experiment during the 1996-2018 period (SKI-IV phase). We searched for an excess of proton recoils above the atmospheric neutrino background from the vicinity of the Galactic Center. No such excess is observed, and limits are calculated for two reference models of dark matter with either a constant interaction cross section or through a scalar mediator. This is the first experimental search for boosted dark matter with hadrons using directional information. The results present the most stringent limits on cosmic-ray boosted dark matter and exclude the dark matter-nucleon elastic scattering cross section between 10^{-33}cm^{2} and 10^{-27}cm^{2} for dark matter mass from 1 MeV/c^{2} to 300 MeV/c^{2}.
RESUMO
This corrects the article DOI: 10.1103/PhysRevLett.130.031802.
RESUMO
BACKGROUND: The long-term use of opioid analgesics is limited by the development of unwanted side-effects, such as tolerance. The molecular mechanisms of morphine anti-nociceptive tolerance are still unclear. The mitochondrial calcium uniporter (MCU) is involved in painful hyperalgesia, but the role of MCU in morphine tolerance has not been uncharacterised. METHODS: Rats received intrathecal injection of morphine for 7 days to induce morphine tolerance. The mechanical withdrawal threshold was measured using von Frey filaments, and thermal latency using the hotplate test. The effects of an MCU inhibitor, antisense oligodeoxynucleotide against cyclic adenosine monophosphate response element (CRE)-binding protein (CREB) or cytoplasmic polyadenylation element-binding protein 1 (CPEB1) in morphine tolerance were examined. RESULTS: Spinal morphine tolerance was associated with an increased expression of neuronal MCU, phospho-CREB (pCREB), and CPEB1 in the spinal cord dorsal horn. MCU inhibition increased the mechanical threshold and thermal latency, and reduced the accumulation of mitochondrial calcium in morphine tolerance. Intrathecal antisense oligodeoxynucleotide against CREB or CPEB1 restored the anti-nociceptive effects of morphine compared with mismatch oligodeoxynucleotide in von Frey test and hotplate test. Chromatin immunoprecipitation with quantitative PCR assay showed that CREB knockdown reduced the interaction of pCREB with the ccdc109a gene (encoding MCU expression) promoter and decreased the MCU mRNA transcription. RNA immunoprecipitation assay suggested that CPEB1 binds to the MCU mRNA 3' untranslated region. CPEB1 knockdown decreased the expression of MCU protein. CONCLUSIONS: These findings suggest that spinal MCU is regulated by pCREB and CPEB1 in morphine tolerance, and that inhibition of MCU, pCREB, or CPEB1 may be useful in preventing the development of opioid tolerance.
Assuntos
Proteína de Ligação a CREB/genética , Canais de Cálcio/metabolismo , Tolerância a Medicamentos/genética , Morfina/farmacologia , Proteínas de Ligação a RNA/genética , Corno Dorsal da Medula Espinal/metabolismo , Analgésicos Opioides/farmacologia , Animais , Masculino , Modelos Animais , Reação em Cadeia da Polimerase , Ratos , Ratos Sprague-DawleyRESUMO
Morphine appears to be the most active metabolite of heroin; therefore, the effects of morphine are important in understanding the ramifications of heroin abuse. Opioid physical dependence (withdrawal response) may have very long-lasting effects on the motivation for reward, including the incubation of cue-induced drug-seeking behavior. However, the exact mechanisms of morphine withdrawal (MW) are not clear yet, and its treatment remains elusive. Periaqueductal gray (PAG) is one of the important sites in the pathogenesis of MW. Here, we used recombinant herpes simplex virus (HSV) vectors that encode the sod2 gene expressing manganese superoxide dismutase (MnSOD) to evaluate its therapeutic potential in MW. Microinjection of HSV vectors expressing MnSOD into the PAG reduced the MW syndrome. MnSOD vectors suppressed the upregulated mitochondrial superoxide, and endoplasmic reticulum stress markers (glucose-related protein 78 (GRP78) and activating transcription factor 6 alpha (ATF6α)) in the PAG induced by MW. Immunostaining showed that mitochondrial superoxide, GRP78 and ATF6α were colocalized with neuronal nuclei (a neuronal-specific marker), suggesting that they are located in the neurons in the PAG. These results suggest that overexpression of MnSOD by HSV vectors may relieve opioid dependence. This study may provide a novel therapeutic approach to morphine physical withdrawal response.
Assuntos
Terapia Genética , Morfina/efeitos adversos , Substância Cinzenta Periaquedutal/metabolismo , Simplexvirus/genética , Síndrome de Abstinência a Substâncias/terapia , Superóxido Dismutase/genética , Fator 6 Ativador da Transcrição/genética , Fator 6 Ativador da Transcrição/metabolismo , Animais , Vetores Genéticos/genética , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Masculino , Ratos , Ratos Sprague-Dawley , Superóxido Dismutase/metabolismoRESUMO
OBJECTIVE: Diabetes is often associated with increased prevalence and severity of periodontal disease. We hypothesized that gingival epithelial cells modify periodontal disease progression and predicted that hyperglycemia would activate an inflammatory response in human gingival epithelial cells (HGECs). MATERIALS AND METHODS: We tested our hypothesis in immortalized HGECs (epi 4 cells) isolated from periodontal tissue and transfected with the simian virus 40 T antigen. The epi 4 cells were cultured in high (25 mM, HG) and normal (6 mM, NG) glucose conditions. RESULTS: The epi 4 cells showed increased interleukin-8 (IL-8) protein secretion and mRNA expression when cultured in HG, compared with in NG. These effects were not associated with increased cell proliferation and were not observed in a hyperosmolar control group (normal glucose with 19 mM mannitol). Increased IL-8 secretion in HG was inhibited by pretreatment with an antioxidant, N-acetylcysteine, or a protein kinase C inhibitor, Ro31-8220. Hyperglycemia did not affect IL-8 secretion by gingival fibroblasts or periodontal ligament cells. In epi 4 cells, hyperglycemia also induced expression of toll-like receptor 2 (TLR2) but not TLR4. CONCLUSION: These findings suggest a potential participation of epithelial cells in periodontal disease during diabetes by evoking an excessive host inflammatory response.
Assuntos
Células Epiteliais/fisiologia , Gengiva/citologia , Interleucina-8/biossíntese , Estresse Oxidativo/fisiologia , Células Cultivadas , Diabetes Mellitus/metabolismo , HumanosRESUMO
We report the systemic cytokine and chemokine response in children with the 2009 pandemic influenza A (H1N1) virus infection. In patients with pneumonia, the serum levels of IFN-γ and IL-5 were significantly higher than those in patients without pneumonia. This tendency was also present for IL-6, IL-8, IL-10, IL-13, and MCP-1 in patients with pneumonia. Among patients with pneumonia, the levels of MCP-1 were significantly higher in the group of patients with pneumonia with severe respiratory failure than patients with mild pneumonia.
Assuntos
Citocinas/sangue , Vírus da Influenza A Subtipo H1N1/imunologia , Influenza Humana/imunologia , Criança , Pré-Escolar , Feminino , Humanos , Influenza Humana/complicações , Masculino , Pneumonia/imunologia , Pneumonia/patologiaRESUMO
WHAT IS KNOWN AND OBJECTIVE: Adrenoleukodystrophy (ALD) is an X-linked disorder and characterized by the accumulation of saturated very long-chain fatty acids. Treatment is still unsatisfactory. Our objective is to report on the effect of the free-radical scavenger, edaravone, in a patient with ALD. CASE SUMMARY: The patient was given edaravone intravenously twice. D-ROM in cerebral spinal fluid decreased dramatically, and a shortening of neuronal transmission time as estimated on somatosensory evoked potential was observed. After terminating the treatment, his symptoms progressively reappeared. WHAT IS NEW AND CONCLUSION: This is the first report of the use of edaravone in ALD. The drug is apparently effective in improving symptoms of ALD and should be evaluated more formally.
Assuntos
Adrenoleucodistrofia/tratamento farmacológico , Antipirina/análogos & derivados , Sequestradores de Radicais Livres/uso terapêutico , Adrenoleucodistrofia/líquido cefalorraquidiano , Antipirina/efeitos adversos , Antipirina/uso terapêutico , Criança , Edaravone , Potenciais Somatossensoriais Evocados/efeitos dos fármacos , Sequestradores de Radicais Livres/efeitos adversos , Humanos , Masculino , Neurônios/efeitos dos fármacos , Espécies Reativas de Oxigênio/líquido cefalorraquidiano , Transmissão Sináptica/efeitos dos fármacos , Extremidade Superior/inervaçãoRESUMO
AIMS: Prolyl aminopeptidase (PAP) degrades only amino-terminal proline from peptides. The food-grade fungus Aspergillus oryzae produces this enzyme only in small amounts. In this paper, we present efficient production of recombinant PAP with an overexpression system of A. oryzae and characterization of its biochemical properties. METHODS AND RESULTS: The gene encoding PAP was overexpressed as a His-tag fusion protein under a taka-amylase gene (amyB) promoter with a limited expressing condition in A. oryzae. The PAP activity in the mycelia grown in rich medium containing glucose (repressing condition) was twice that in starch (inducing condition). The enzyme prepared as cell-free extract was partially purified through two-step column chromatography. The PAP was estimated to be a hexameric protein and exhibited salt tolerance against NaCl of up to 4 mol l(-1). CONCLUSIONS: Aspergillus oryzae PAP was produced under the repressing condition of amyB promoter in a PAP-overexpressing strain and purified 1800-folds. Overproduction of PAP under promoter-inducing conditions led to an increase in inactive PAP, possibly because of irregular folding. SIGNIFICANCE AND IMPACT OF THE STUDY: PAP with a high specific activity and salt tolerance may be used effectively in the manufacturing processes of fermented foods.
Assuntos
Aminopeptidases/biossíntese , Aspergillus oryzae/enzimologia , Microbiologia Industrial , Aminopeptidases/genética , Aminopeptidases/metabolismo , Aspergillus oryzae/genética , Meios de Cultura , Regiões Promotoras Genéticas , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismoRESUMO
AIMS: Aspartyl aminopeptidase (DAP) has a high degree of substrate specificity, degrading only amino-terminal acidic amino acids from peptides. Therefore, attention is focused here on the efficient production of this enzyme by a recombinant Aspergillus oryzae and characterization of its biochemical properties. METHODS AND RESULTS: The gene encoding DAP was overexpressed under a taka-amylase gene promoter, with His-tag linker in A. oryzae, during cultivation in a Co(2+)-containing medium. The enzyme was extracted from the mycelia and purified with immobilized nickel ion absorption chromatography using a buffer containing cobalt ion and imidazole. The active fraction was further purified with gel filtration chromatography. The resultant, electrophoretically pure enzyme displayed a molecular mass of 520 kDa. This enzyme displayed high reactivity towards peptide substrate rather than synthetic substrates. CONCLUSIONS: Recombinant A. oryzae DAP was purified to homogeneity with an increased specific activity, when cultivated in a Co(2+)-rich medium. Moreover, the use of suitable metal ions in microbial cultivation and purification processes may help in increasing the specific activity of other metalloproteases and their functional analysis. SIGNIFICANCE AND IMPACT OF THE STUDY: Recombinant DAP produced using a cobalt ion in culture media of A. oryzae and purification process allow high yield of the enzyme activity.
Assuntos
Aspergillus oryzae/enzimologia , Glutamil Aminopeptidase/isolamento & purificação , Aspergillus oryzae/genética , Cromatografia em Gel , Cromatografia por Troca Iônica , Cobalto/farmacologia , Meios de Cultura/química , Glutamil Aminopeptidase/metabolismo , Peso Molecular , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Especificidade por SubstratoRESUMO
BACKGROUND/AIMS: The aim of this study was to evaluate the outcome of patients undergoing colorectal resection for colon cancer using a minilaparotomy approach or conventional surgical procedure. METHODOLOGY: In a prospective randomized trial, twenty consecutive patients undergoing colon resection by minilaparotomy and 26 patients undergoing conventional open colorectal resection were evaluated. Immunologic, metabolic and hemodynamic studies were performed in all patients. Cell surface markers were used to characterize Th1/2 balance, using flow cytometry. Indirect calorimetry to measure energy expenditure, and pulse dye densitometry for a hemodynamic study were performed in patients until 14 POD. RESULTS: The lengths of laparotomy incisions were 7.5+/-1.5 cm and 20.5+/-2.5 cm in the minilaparotomy and conventional group, respectively. Mean operative time, morbidity and postoperative hospital stay of the two groups was not significantly different. However, mean operative blood loss, days to p.o. liquids and walking, and amount of analgesic usage were significantly less in the minilaparotomy group. The postoperative ratio of Th1/2 in CD4+T cells was decreased in both groups, but no significant difference was seen between the groups. Significant increase of resting energy expenditure and cardiac index was seen until day 3 in the conventional group, whereas those values increased until day 1 in the minilaparotomy group. CONCLUSIONS: Compared with conventional colorectal resection for colon cancer, colorectal resection by minilaparotomy results in a more rapid return of bowel function, less pain and host response. However, the alternations of the host response for surgical stress between the two groups are similar in the early postoperative stage (days 1-2).
Assuntos
Neoplasias do Colo/cirurgia , Idoso , Idoso de 80 Anos ou mais , Contagem de Linfócito CD4 , Calorimetria Indireta , Colectomia , Neoplasias do Colo/fisiopatologia , Metabolismo Energético , Feminino , Citometria de Fluxo , Hemodinâmica , Humanos , Interferon gama/análise , Interleucina-4/análise , Laparotomia/métodos , Masculino , Pessoa de Meia-Idade , Procedimentos Cirúrgicos Minimamente Invasivos , Estudos ProspectivosRESUMO
BACKGROUND/AIMS: Systemic inflammatory response syndrome (SIRS) includes a number of pathologic states because of its loose definition. This study assessed differences in metabolic and circulatory host responses in various patients with SIRS perioperatively. METHODOLOGY: Fifty-four patients who underwent abdominal surgeries [gastric resection (n=20), colorectal resection (n=24), hepatic resection (n=8)] were divided into two groups: Group A; SIRS (+) on 1 postoperative day (POD), (n=29), B; SIRS (-) on 1 POD, (n=25). The other eight non-operated patients with SIRS caused by infection were enrolled in Group C, as common SIRS. Indirect calorimetry, body impedance measurement to assess water compartments and pulse dye-densitometry for hemodynamic examination were performed in subjects until 14 POD. RESULTS: The ratio of energy expenditure to basal energy expenditure (%REE) was significantly increased postoperatively, and there were significant differences on %REE from 3 POD to 14 POD between groups A and B. However, %REE in group C was 162+/-23%, which was significantly increased compared with that at 1 POD of groups A (130 +/- 17%) and B (125+/-18%). Cardiac output in group A showed a significant increase until 3 POD compared with that in group B but was significantly lower than that in group C. CONCLUSIONS: Subjects with common SIRS caused by infection were significantly more hypermetabolic than subjects with postoperative SIRS. Adequate energy intake and circulatory management should be cautiously determined according to the severity of SIRS.
Assuntos
Volume Sanguíneo/fisiologia , Débito Cardíaco/fisiologia , Procedimentos Cirúrgicos do Sistema Digestório/efeitos adversos , Metabolismo Energético/fisiologia , Síndrome de Resposta Inflamatória Sistêmica/metabolismo , Síndrome de Resposta Inflamatória Sistêmica/fisiopatologia , Idoso , Composição Corporal , Água Corporal , Estudos de Casos e Controles , Densitometria , Impedância Elétrica , Feminino , Humanos , Líquido Intracelular , Masculino , Pessoa de Meia-Idade , Síndrome de Resposta Inflamatória Sistêmica/etiologiaRESUMO
BACKGROUND/AIMS: Gasless laparoscopic surgery using the abdominal wall lifting (AWL) method was first developed in Japan and has been used in various surgical fields. The AWL method allows the use of conventional reusable surgical instruments. The purpose of this study was to compare the cost-effectiveness of laparoscopic cholecystectomy (LSC) using the AWL method in relation to that using pneumoperitoneum (P) method. METHODOLOGY: Retrospective analysis of 431 LSC procedures between 1991 and 2004 was performed. The two surgical groups consisted of consecutively operated patients with a diagnosis of cholecystolithiasis or gallbladder polyps. One group consisted of 224 LSC procedures performed using the P method from 1992 to 1998 and the other group comprised 207 LSC performed using the AWL method from 1998 to 2004. All instruments used in the P method were disposable, whereas trocars, scissors, dissectors, graspers and L-hook electrodes (excluding clips) used in the AWL method were reusable. Hospital expenses, length of hospital admission and complication rates were analyzed. RESULTS: Mean hospital cost per case for LSC using the AWL method (dollars 6743) was 7% less expensive than that using the P method (dolars 7215). Costs of operative equipment contributed to the difference (mean dollars 912 per case) in total cost. Conversion to open cholecystectomy occurred in 6 cases (2.9%) using the AWL method and 7 cases (3.1%) using the P method. There were no significant differences in length of hospital admission or complication rates between the two groups. CONCLUSIONS: LSC using AWL method was less expensive than that using P method. This is mainly due to the use of reusable instruments in the AWL method. If LSC is performed using the AWL method instead of using disposable equipment, considerable savings can be achieved without compromising patient safety.
Assuntos
Parede Abdominal/cirurgia , Colecistectomia Laparoscópica/economia , Colecistectomia Laparoscópica/métodos , Pneumoperitônio Artificial , Adulto , Idoso , Colecistectomia Laparoscópica/efeitos adversos , Colecistectomia Laparoscópica/instrumentação , Análise Custo-Benefício , Equipamentos Descartáveis , Reutilização de Equipamento , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pneumoperitônio Artificial/efeitos adversos , Pneumoperitônio Artificial/economia , Pneumoperitônio Artificial/instrumentação , Pneumoperitônio Artificial/métodos , Equipamentos CirúrgicosRESUMO
BACKGROUND/AIMS: The age-associated dysregulation of hemodynamic, metabolic and immune responses contributes to the high incidence of complications after major abdominal surgery. METHODOLOGY: Ninety-five patients who underwent gastric resection (n=51) and colorectal resection (n=44) were divided according to age into Groups A (n=45, less than 70 years old), B (n=30, 70-79 years) and C (n=20, over 80 years). Flow cytometric analysis of CD4+ lymphocytes for interferon (IFN)-gamma and interleukin (IL)-4 production determined the Th1/2 balance. Energy expenditure was measured by indirect calorimetry, and hemodynamics were studied using pulse dye densitometry. RESULTS: Surgical procedures, operating time, blood loss and morbidity did not significantly differ among the three groups. The cardiac index (CI) in group A and B increased significantly over preoperative levels until POD 3, but there were no significant perioperative changes in the CI levels of group C. Resting energy expenditure levels changed similarly to those of CI. The postoperative Th1/2 ratio decreased from young to elderly to very elderly patients, although no differences were significant before surgery. The postoperative percentage of CD4+IFN-gamma +T cells (Th1) in group C decreased significantly despite of no significant changes in that of group A and B. In contrast, the ratio of CD4+IL-4+T cells (Th2) in the all groups significantly increased after surgery. CONCLUSIONS: Host responses in elderly patients after major abdominal surgery were more hyperdynamic and hypermetabolic than those of young patients. Postoperative dysregulation of the Th1/2 balance was also associated with aging. However, host responses appear to significantly differ between elderly and very elderly patients.
Assuntos
Colectomia , Gastrectomia , Idoso , Idoso de 80 Anos ou mais , Perda Sanguínea Cirúrgica , Volume Sanguíneo , Calorimetria Indireta , Débito Cardíaco , Metabolismo Energético , Feminino , Citometria de Fluxo , Humanos , Interferon gama/metabolismo , Interleucina-4/metabolismo , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Período Pós-Operatório , Células Th1 , Células Th2RESUMO
Recent epidemiological studies have shown that vascular risk factors may be involved in Alzheimer's disease (AD) as well as dementia in general. To investigate the relation between a vascular disorder and AD pathology, current criteria are defective because most depend on exclusion of a cerebrovascular disorder. Epidemiological studies have indicated the possibilities that arteriosclerosis, abnormal blood pressure, diabetes mellitus and smoking may be related to the pathogenesis of AD. As for the mechanism that vascular disorders influence AD, it is presumed that amyloid deposition may be caused by a vascular disorder. Alternatively, a vascular event may cause progression of subclinical AD to a clinical stage. Insulin resistance and apolipoprotein E may also be involved in these mechanisms. Our studies show that ischemia-induced the Alzheimer-associated gene presenilin 1 (PS1) and endoplasmic reticulum-stress, generated from a vascular disorder, may unmask clinical AD symptoms caused by presenilin mutation, suggesting that a vascular factor might be involved in the onset of familial AD.
Assuntos
Doença de Alzheimer/epidemiologia , Circulação Cerebrovascular/fisiologia , Doença de Alzheimer/diagnóstico , Humanos , Fatores de RiscoRESUMO
Ser-473 is solely phosphorylated in vivo in the tail region of neurofilament L (NF-L). With peptides including the native phosphorylation site, it was not possible to locate responsible kinases. We therefore adopted full-length dephosphorylated NF-L as the substrate, and employed MALDI/TOF (matrix-assisted laser desorption and ionization/time of flight) mass spectrometry and a site-specific phosphorylation-dependent antibody recognizing Ser-473 phosphorylation. The antibody showed that casein kinase I (CK I) as well as casein kinase II (CK II) phosphorylated Ser-473 in vitro, while neither GSK-3beta nor calcium/calmodulin-dependent protein kinase II did so. However, the mass spectra of the tail fragments of the phosphorylated NF-L indicated that CK II was the kinase mediating Ser-473 phosphorylation in vitro as opposed to CK I, because CK I phosphorylated another site as well as Ser-473 in vitro. The antibody also demonstrated that NF-L phosphorylated at Ser-473 was abundant in the neuronal perikarya of the rat cortex, indicating that phosphorylation of Ser-473 may take place there. This result may support the suggestion that CK II is the kinase responsible for Ser-473 phosphorylation. Despite many reports showing that CK I mediates phosphorylation of neurofilaments, CK II may phosphorylate NF-L in vivo.
Assuntos
Proteínas de Neurofilamentos/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Serina/metabolismo , Sequência de Aminoácidos , Animais , Especificidade de Anticorpos , Caseína Quinase II , Bovinos , Imuno-Histoquímica , Proteínas de Neurofilamentos/química , Proteínas de Neurofilamentos/imunologia , Fosforilação , Ratos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
Free-radicals and other reactive oxygen species (ROS) have been implicated as being major damaging species in pathology and they have been widely investigated. Using 1,1'-diphenyl-2-picrylhydrazyl (DPPH), we estimated total free radical scavenging activity in the low-molecular-weight nonenzymatic fraction (LMNEF) of human whole saliva. The activity of the whole saliva and serum were measured in terms of the rate of decrease in the absorbance at 517 nm in a 40% ethanol DPPH solution (pH 7.4) at room temperature. The DPPH activity of saliva and serum showed a significant linear relationship. The mean DPPH activities of saliva from 257 subjects aged 4-72 was found to be 0.389+/-.190 micromol/ml and bore no relation to age or sex. The activity in saliva of 86 subjects aged 4-11 was significantly different before and after exhaustive aerobic dance exercise for 1 hr. Physical exercise markedly decreased free radical scavenging activity in whole saliva of children. On the basis of the above results, we concluded that DPPH is useful for evaluating the total antioxidant capacity of LMNEF of human saliva.
Assuntos
Bepridil/análogos & derivados , Bepridil/metabolismo , Exercício Físico , Sequestradores de Radicais Livres/metabolismo , Picratos , Espécies Reativas de Oxigênio/metabolismo , Saliva/metabolismo , Adolescente , Adulto , Idoso , Antioxidantes/metabolismo , Compostos de Bifenilo , Criança , Pré-Escolar , Feminino , Sequestradores de Radicais Livres/sangue , Humanos , Concentração de Íons de Hidrogênio , Indicadores e Reagentes/metabolismo , Masculino , Pessoa de Meia-Idade , OxirreduçãoRESUMO
BACKGROUND: Production of heat shock protein 70 (HSP70) in the heart is induced by hemodynamic stress, but its intracellular signal transduction system has not been elucidated well. OBJECTIVE: To investigate the hypothesis that protein kinase A (PKA)-dependent and protein kinase C (PKC)dependent systems are involved in the pressure-induced expression of HSP70 mRNA in perfused adult rat heart METHODS: Isolated tetrodotoxin-arrested Sprague-Dawley rat hearts were perfused as Langendorff preparations at a constant aortic pressure of 60 mmHg. Aortic pressure in rats of the pressure-overloaded group was elevated from 60 to 120 mmHg for 2-120 min. cAMP contents and rates of synthesis of protein were measured by radioimmunoassay and the incorporation of [14C]-phenylalanine into total heart protein, respectively. Expression of HSP70 mRNA was determined by Northern blot analysis. RESULTS: Elevation of aortic pressure significantly increased cAMP content after 2 min of perfusion (by 41%), significantly increased rates of synthesis of protein during the second hour of perfusion (by 41%), and induced expression of HSP70 mRNA maximally after 60 min of perfusion (2.7-fold the control value). Exposure to glucagon, forskolin or 1 -methyl-3-isobutylxanthine mimicked increases in these parameters caused by elevation of aortic pressure. Administration of a selective PKA inhibitor, H-89, significantly prevented induction of increases in expression of HSP70 mRNA and rates of synthesis of protein by a high pressure overload and exposure to agents that increase cAMP content. Furthermore, administration of phorbol ester induced expression of HSP70 mRNA. Administration of a PKC inhibitor, calphostin C, significantly prevented induction of increases in expression of HSP70 mRNA by a pressure overload and by exposure to phorbol ester. CONCLUSIONS: These results suggest that the pressure-induced induction of production of HSP70 is regulated both by PKA-dependent and by PKC-dependent systems during periods of active synthesis of protein in adult rat heart.
Assuntos
Pressão Sanguínea/genética , Pressão Sanguínea/fisiologia , Proteínas Quinases Dependentes de AMP Cíclico/fisiologia , Proteínas de Choque Térmico HSP70/genética , Miocárdio/metabolismo , Proteína Quinase C/fisiologia , RNA Mensageiro/genética , Sulfonamidas , 1-Metil-3-Isobutilxantina/farmacologia , Animais , Pressão Sanguínea/efeitos dos fármacos , Cardiomegalia/etiologia , Cardiomegalia/genética , Cardiomegalia/fisiopatologia , Colforsina/farmacologia , AMP Cíclico/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Expressão Gênica/efeitos dos fármacos , Glucagon/farmacologia , Hipertensão/genética , Hipertensão/fisiopatologia , Técnicas In Vitro , Isoquinolinas/farmacologia , Masculino , Naftalenos/farmacologia , Perfusão , Biossíntese de Proteínas , Proteína Quinase C/antagonistas & inibidores , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Transdução de SinaisRESUMO
The messenger RNA expression of presenilin-1, an important gene responsible for early-onset familial Alzheimer's disease, was investigated in the embryonic rat brain with in situ hybridization histochemistry using an oligonucleotide probe specific to the messenger RNA. It was also compared with that of beta-amyloid precursor protein messenger RNA. Presenilin-1 and beta-amyloid precursor protein messenger RNA were abundantly expressed throughout the central nervous system in the embryonic day 13, 17 and 20 rat brain. Presenilin-1 messenger RNA was strongly expressed in both neuroepithelium and differentiating fields. In contrast, beta-amyloid precursor protein messenger RNA was preferentially expressed in differentiating fields, while low expression of beta-amyloid precursor protein messenger RNA was seen in neuroepithelium. Although the expression patterns of these two messenger RNAs were basically similar, there seemed to be a tendency that presenilin-1 messenger RNA was preferentially expressed in immature neurons, while beta-amyloid precursor protein messenger RNA was preferentially expressed in mature neurons, suggesting that presenilin-1 is expressed earlier than beta-amyloid precursor protein and that presenilin-1 is involved in beta-amyloid precursor protein processing. These data raise the possibility that presenilin-1 and beta-amyloid precursor protein co-operatively play pivotal roles in rat neurogenesis.
Assuntos
Precursor de Proteína beta-Amiloide/genética , Química Encefálica , Encéfalo/embriologia , Proteínas Fetais/genética , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Membrana/genética , RNA Mensageiro/genética , Animais , Diferenciação Celular , Células Epiteliais/metabolismo , Idade Gestacional , Hipertrofia , Hibridização In Situ , Osso Occipital/citologia , Osso Occipital/embriologia , Especificidade de Órgãos , Osteoblastos/metabolismo , Presenilina-1 , Ratos , Ratos WistarRESUMO
Electrospray ionization mass spectrometry (ESI-MS) was applied to the analysis of the dissociation and denaturation processes of a heterodimeric yeast killer toxin SMKT. The two distinct subunits of SMKT noncovalently associate under acidic conditions, but become dissociated and denatured under neutral and basic conditions. In order to understand the unique pH-dependent denaturation mechanism of this protein, a pH titration was performed by utilizing ESI-MS. The molecular ions of the heterodimer which possesses the highly ordered structure, were mainly observed below pH 4.6. However, the two subunits immediately dissociated at this pH. The spectra measured with various settings of the mass spectrometer indirectly demonstrated that the pH-dependent dissociation occurs in the liquid phase. The current result as well as the three-dimensional structure of SMKT suggest that the deprotonation of a specific carboxyl group triggers a cooperative dissociation process of this protein. In conclusion, the pH titration of a protein by ESI-MS is particularly effective, when the unfolding process or the biological function of the protein is related to the interaction with other molecules.