Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
1.
Front Cell Infect Microbiol ; 14: 1367885, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38784566

RESUMO

Objective: This study aims to investigate the clinical application value of Metagenome Next-Generation Sequencing (mNGS) for pulmonary diffuse exudative lesions. Methods: From January 1, 2014, to November 31, 2021, 136 cases with chest radiologic presentations of pulmonary diffuse exudative lesions admitted to Fujian Provincial Hospital were included in the study; of those, 77 patients underwent mNGS pathogen detection. Based on the pathogen detection outcomes and clinical diagnoses, patients were categorized into an infection group (IG) and a non-infection group (NIG). A comparison was made between the diagnostic efficacy of the mNGS technique and traditional culture methods. Meanwhile, 59 patients clinically identified as having infectious pulmonary diffuse exudative lesions but who did not receive mNGS testing were designated as the non-NGS infection group (non-IG). A retrospective cohort study was conducted on patients in both the IG and non-IG, with a 30-day all-cause mortality endpoint used for follow-up. Outcomes: When compared to conventional culture methods, mNGS demonstrated an approximate 35% increase in sensitivity (80.0% vs 45.5%, P<0.001), without significant disparity in specificity (77.3% vs 95.5%, P=0.185). Under antibiotic exposure, the positivity rate detected by mNGS was notably higher than that by traditional culture methods, indicating that mNGS is less affected by exposure to antibiotics (P<0.05). Within 30 days, the all-cause mortality rate for patients in the IG versus the non-IG was 14.55% and 37.29%, respectively (P<0.05). Following a COX regression analysis to adjust for confounding factors, the analysis revealed that a CURB-65 score ≥3 points (HR=3.348, P=0.001) and existing cardiovascular disease (HR=2.473, P=0.026) were independent risk factors for these patients. Conversely, mNGS testing (HR=0.368, P=0.017) proved to be an independent protective factor. Conclusion: mNGS technology makes it easier to pinpoint the cause of pulmonary diffuse infectious exudative lesions without much interference from antibiotics, helping doctors spot and diagnose these issues early on, thereby playing a key role in helping them decide the best treatment approach for patients. Such conclusions may have a bias, as the performance of traditional methods might be underestimated due to the absence of complete results from other conventional diagnostic techniques like serological testing and PCR.


Assuntos
Sequenciamento de Nucleotídeos em Larga Escala , Metagenoma , Humanos , Estudos Retrospectivos , Masculino , Feminino , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Pessoa de Meia-Idade , Idoso , Sensibilidade e Especificidade , Adulto , Pneumopatias/microbiologia , Pneumopatias/diagnóstico , Pulmão/microbiologia , Pulmão/patologia , Idoso de 80 Anos ou mais , Metagenômica/métodos
2.
Soft Matter ; 19(48): 9520-9530, 2023 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-38050468

RESUMO

The collapse of low-saturation liquid-containing granular materials is prevalent in nature and industrial processes, and understanding the associated transient dynamics is extremely important for exploring such complex flow processes. In this paper, the collapse of a finite-size wet granular column is systematically studied and the determinants affecting its dynamics are analyzed based on the discrete element model for wet particles and the corresponding small-scale experiments. With the aid of parametric analysis, the dimensionless cohesion parameter containing the system size and grain-scale bond number is proposed, and its relevance in characterizing column stability and collapse dynamics of wet granular materials is further confirmed. For the collapse of wet granular columns with a fixed aspect ratio, the initial height contained in the cohesion parameter is verified to be a manifestation of the finite size effect, which is present in a wet granular collapse and is coupled with the cohesive effect. Such a coupling effect is taken into account in our proposed scaling laws that can be applied to uniformly describe the deposit morphology of wet granular columns after collapse.

3.
Front Cell Infect Microbiol ; 13: 1179552, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37533930

RESUMO

Introduction: This study explored the differences in clinical characteristics between the 2009 pandemic influenza A (H1N1) and SARS-CoV-2 BA.2 variant (Omicron) infections in patients younger than age 65 years, to improve identification of these diseases and better respond to the current epidemic. Methods: Data from 127 patients with the 2009 pandemic influenza A (H1N1) diagnosed between May and July of 2009 and 3,265 patients with Omicron diagnosed between March and May of 2022 were collected. Using a 1:2 match based on age (difference <2 years), sex, and underlying diseases, data from 115 patients with the 2009 pandemic influenza A (H1N1) infection (H1N1 group) and 230 patients with SARS-CoV-2 Omicron BA.2 infection (Omicron group) were analyzed. The clinical manifestations were compared between the groups, logistic regression was performed to identify possible independent risk factors for each group, and multiple linear regression was used to analyze the factors predicting time for nucleic acid negativization (NAN). Results: The median [interquartile range] age of the two groups was 21 [11, 26] years. Compared with the H1N1 group, the Omicron group had: lower white blood cell counts and C-reactive protein levels; less fever, nasal congestion, sore throat, cough, sputum, and headache; and more olfactory loss, muscle soreness, and lactate dehydrogenase (LDH) abnormalities. Patients in the Omicron group used fewer antibiotics and antiviral drugs, and the time for NAN was longer (17 [14,20] VS 4 [3,5] days, P<0.001). Logistic regression showed that fever, cough, headache, and increased white blood cell count were more strongly correlated with the H1N1 group, while muscle soreness and LDH abnormalities were more strongly correlated with the Omicron group. Fever (B 1.529, 95% confidence interval [0.149,2.909], P=0.030) significantly predicted a longer time for NAN in patients with Omicron. Discussion: There are significant differences in clinical characteristics between SARS-CoV-2 Omicron infection and the 2009 pandemic influenza A (H1N1) infection. Recognition of these differences has important implications for clinical practice.


Assuntos
COVID-19 , Vírus da Influenza A Subtipo H1N1 , Influenza Humana , Humanos , Idoso , Pré-Escolar , Influenza Humana/diagnóstico , Influenza Humana/epidemiologia , SARS-CoV-2/genética , COVID-19/diagnóstico , COVID-19/epidemiologia , Vírus da Influenza A Subtipo H1N1/genética , Tosse , Estudos Retrospectivos , Estações do Ano , Mialgia/epidemiologia , Cefaleia
4.
J Chromatogr A ; 1692: 463826, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36774914

RESUMO

Panax ginseng can be generally divided into mountain-cultivated ginseng (MCG) and garden-cultivated ginseng (GCG). The market price of MCG is significantly higher than that of GCG. However, the chemical compositions of MCG and the differences from GCG remained unclear. In this study, an integrated strategy combing an offline two-dimensional liquid chromatography separation, LTQ-orbitrap dual mode acquisition, and Q-trap full quantification/quasi-quantification was proposed to explore and compare the chemical compositions of MCG. Consequently, 559 ginsenosides were characterized, among which 437 ginsenosides were in-depth characterized with α-chain and ß-chain annotated. Subsequently, enhanced quantification of 213 ginsenosides was conducted in 57 batches of MCG and GCG. Ginsenosides were found more abundant in MCG than GCG. In addition, 25-year-old MCG could be distinctly differentiated from 15/20-year-old MCG. This strategy facilitated the enhanced profiling and comparison of ginsenosides, improved the quality control tactics of MCG and provided a reference approach for other ginseng related products.


Assuntos
Ginsenosídeos , Panax , Ginsenosídeos/análise , Jardins , Panax/química , Cromatografia Líquida de Alta Pressão/métodos , Controle de Qualidade
5.
World Neurosurg ; 129: e409-e416, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31146039

RESUMO

OBJECTIVE: The globus pallidus internus (GPi) and subthalamic nucleus (STN) are therapeutic targets for deep brain stimulation (DBS) in the treatment of isolated dystonia. We conducted a meta-regression analysis on long-term studies of bilateral DBS in the GPi and STN to compare the relative effects of the 2 approaches. METHODS: We systematically searched the PubMed, Embase, and Cochrane Controlled Register of Trials databases to identify studies reporting the treatment outcomes of GPi DBS and STN DBS for isolated dystonia. The primary outcome measure was the change in the Burke-Fahn-Marsden dystonia rating scale movement score between the baseline and follow-up evaluations. We performed a regression analysis using a random effects model. RESULTS: A total of 42 follow-up evaluations (30 for GPi and 12 for STN) nested in 19 studies (16 of GPi and 3 of STN) were included in our analysis. The results from univariate regression analysis suggested that shorter disease duration and STN stimulation were associated with a greater standardized change in the Burke-Fahn-Marsden dystonia rating scale movement score. On combining the factors into 1 model, only the disease duration remained significant. The regression analysis results of the GPi and STN subgroups revealed more persistent improvement after STN stimulation. CONCLUSIONS: A shorter disease duration correlated positively with better DBS outcomes. The STN appeared to be an optimized stimulation target for the treatment of isolated dystonia, although randomized controlled trials are needed to compare the treatment efficacy of GPi DBS and STN DBS.


Assuntos
Estimulação Encefálica Profunda/métodos , Distonia/terapia , Distúrbios Distônicos/terapia , Globo Pálido/fisiopatologia , Núcleo Subtalâmico/fisiopatologia , Distonia/fisiopatologia , Distúrbios Distônicos/fisiopatologia , Humanos , Análise de Regressão , Resultado do Tratamento
6.
World J Gastroenterol ; 20(16): 4626-35, 2014 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-24782615

RESUMO

AIM: To investigate the relationship between neuronal nitric oxide synthase (nNOS) expression and the natriuretic peptide signaling pathway in the gastric fundus of streptozotocin (STZ)-induced diabetic mice. METHODS: Diabetic mice were induced by injection of STZ solution. Immunofluorescence labeling of HuC/D, nNOS and natriuretic peptide receptor-A, B, C (NPRs) in the gastric fundus (GF) was used to observe nNOS expression and whether NPRs exist on enteric neurons. The expression levels of nNOS and NPRs in the diabetic GF were examined by western blotting. An isometric force transducer recorded the electric field stimulation (EFS)-induced relaxation and contraction in the diabetic GF. An intracellular recording method assessed EFS-induced inhibitory junction potentials (IJP) on the GF. GF smooth muscles acquired from normal mice were incubated with different concentrations of the NPRs agonist C-type natriuretic peptide (CNP) for 24 h, after which their nNOS expressions were detected by western blotting. RESULTS: Eight weeks after injection, 43 diabetic mice were obtained from mouse models injected with STZ. Immunofluorescence indicated that the number of NOS neurons was significantly decreased and that nNOS expression was significantly downregulated in the diabetic GF. The results of physiological and electrophysiological assays showed that the EFS-induced relaxation that mainly caused by NO was significantly reduced, while the contraction was enhanced in the diabetic GF. EFS-induced IJP showed that L-NAME sensitive IJP in the diabetic GF was significantly reduced compared with control mice. However, both NPR-A and NPR-B were detected on enteric neurons, and their expression levels were upregulated in the diabetic GF. The nNOS expression level was downregulated dose-dependently in GF smooth muscle tissues exposed to CNP. CONCLUSION: These findings suggested that upregulation of the NPs signaling pathway may be involved in GF neuropathy caused by diabetes by decreasing nNOS expression.


Assuntos
Diabetes Mellitus Experimental/enzimologia , Sistema Nervoso Entérico/enzimologia , Fundo Gástrico/inervação , Músculo Liso/inervação , Peptídeos Natriuréticos/metabolismo , Neurônios Nitrérgicos/enzimologia , Óxido Nítrico Sintase Tipo I/metabolismo , Animais , Glicemia/metabolismo , Peso Corporal , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/fisiopatologia , Regulação para Baixo , Estimulação Elétrica , Sistema Nervoso Entérico/fisiopatologia , Masculino , Camundongos Endogâmicos ICR , Contração Muscular , Óxido Nítrico/metabolismo , Receptores do Fator Natriurético Atrial/metabolismo , Transdução de Sinais , Estreptozocina , Técnicas de Cultura de Tecidos , Regulação para Cima
7.
PLoS One ; 9(2): e86109, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24516526

RESUMO

Partial obstruction of the small intestine causes obvious hypertrophy of smooth muscle cells and motility disorder in the bowel proximate to the obstruction. To identify electric remodeling of hypertrophic smooth muscles in partially obstructed murine small intestine, the patch-clamp and intracellular microelectrode recording methods were used to identify the possible electric remodeling and Western blot, immunofluorescence and immunoprecipitation were utilized to examine the channel protein expression and phosphorylation level changes in this research. After 14 days of obstruction, partial obstruction caused obvious smooth muscle hypertrophy in the proximally located intestine. The slow waves of intestinal smooth muscles in the dilated region were significantly suppressed, their amplitude and frequency were reduced, whilst the resting membrane potentials were depolarized compared with normal and sham animals. The current density of voltage dependent potassium channel (KV) was significantly decreased in the hypertrophic smooth muscle cells and the voltage sensitivity of KV activation was altered. The sensitivity of KV currents (IKV) to TEA, a nonselective potassium channel blocker, increased significantly, but the sensitivity of IKv to 4-AP, a KV blocker, stays the same. The protein levels of KV4.3 and KV2.2 were up-regulated in the hypertrophic smooth muscle cell membrane. The serine and threonine phosphorylation levels of KV4.3 and KV2.2 were significantly increased in the hypertrophic smooth muscle cells. Thus this study represents the first identification of KV channel remodeling in murine small intestinal smooth muscle hypertrophy induced by partial obstruction. The enhanced phosphorylations of KV4.3 and KV2.2 may be involved in this process.


Assuntos
Obstrução Intestinal/fisiopatologia , Ativação do Canal Iônico , Músculo Liso/fisiopatologia , Canais de Potássio Shab/metabolismo , Canais de Potássio Shal/metabolismo , 4-Aminopiridina/farmacologia , Animais , Membrana Celular/efeitos dos fármacos , Membrana Celular/fisiologia , Capacitância Elétrica , Imunofluorescência , Secções Congeladas , Hipertrofia , Ativação do Canal Iônico/efeitos dos fármacos , Masculino , Potenciais da Membrana/efeitos dos fármacos , Camundongos Endogâmicos ICR , Músculo Liso/efeitos dos fármacos , Fosforilação/efeitos dos fármacos , Subunidades Proteicas/metabolismo , Tetraetilamônio/farmacologia
8.
Eur J Pharmacol ; 720(1-3): 276-85, 2013 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-24157974

RESUMO

NO and H2S are gaseous signaling molecules that modulate smooth muscle motility. We aimed to identify expressions of enzymes that catalyze H2S and NO generation in mouse gastric smooth muscle, and determine relationships between endogenous H2S and NO in regulation of smooth muscle motility. Western blotting and immunocytochemistry methods were used to track expressions of neuronal nitric oxide synthase (nNOS), endothelial nitric oxide synthase (eNOS), cystathionine ß-synthase (CBS) and cystathionine γ-lyase (CSE) in gastric smooth muscles. Smooth muscle motility was recorded by isometric force transducers. cGMP production was measured by a specific radioimmunoassay. We found that CBS, CSE, eNOS, and nNOS were all expressed in mice gastric antral smooth muscle tissues, and in cultured gastric antral smooth muscle cells. AOAA significantly inhibited smooth muscle contractions in the gastric antrum, which was significantly recovered by NaHS, while PAG had no significant effect. l-NAME enhanced contractions. NaHS at low concentrations increased basal tension but decreased it at high concentrations. SNP significantly inhibited the contractions, which could be recovered by NaHS both in the absence and presence of CuSO4. ODQ did not block NaHS-induced excitatory effect, while IBMX partially blocked this effect. cGMP production in smooth muscle was significantly increased by SNP but was not affected by NaHS. All these results suggest that endogenous H2S and NO appear to play opposite roles in regulating gastric motility and their effects may be via separate signal transduction pathways. Intracellular H2S/NO levels may be maintained in a state of balance to warrant normal smooth muscle motility.


Assuntos
Motilidade Gastrointestinal/efeitos dos fármacos , Sulfeto de Hidrogênio/farmacologia , Óxido Nítrico/farmacologia , Alcinos/farmacologia , Ácido Amino-Oxiacético/farmacologia , Animais , Cistationina beta-Sintase/antagonistas & inibidores , Cistationina beta-Sintase/fisiologia , Cistationina gama-Liase/antagonistas & inibidores , Cistationina gama-Liase/fisiologia , Glicina/análogos & derivados , Glicina/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos ICR , Contração Muscular/efeitos dos fármacos , Músculo Liso/efeitos dos fármacos , Músculo Liso/fisiologia , NG-Nitroarginina Metil Éster/farmacologia , Doadores de Óxido Nítrico/farmacologia , Óxido Nítrico Sintase Tipo II/antagonistas & inibidores , Óxido Nítrico Sintase Tipo II/fisiologia , Óxido Nítrico Sintase Tipo III/antagonistas & inibidores , Óxido Nítrico Sintase Tipo III/fisiologia , Nitroprussiato/farmacologia , Estômago/efeitos dos fármacos , Estômago/fisiologia , Sulfetos/farmacologia
9.
Peptides ; 40: 104-11, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23352981

RESUMO

Our previous study demonstrated that natriuretic peptides (NPs) play an inhibitory role in regulation of gastric smooth muscle motility. However, it is not clear whether NPs are involved in diabetics-induced loss of gastric interstitial cell of Cajal (ICC). The present study was designed to investigate the relationship between diabetics-induced loss of gastric ICC and natriuretic peptide signaling pathway in streptozotocin (STZ)-induced diabetic mice. The results showed that the protein expression levels of c-Kit and membrane-bound stem cell factor (mSCF) in gastric smooth muscle layers were decreased in STZ-induced diabetic mice. However, both mRNA and protein expression levels of natriuretic peptide receptor (NPR)-A, B and C were increased in the same place of the diabetic mice. The amplitude of spontaneous contraction in gastric antral smooth muscles was inhibited by C-type natriuretic peptide (CNP) dose-dependently and the inhibitory effect was potentiated in diabetic mice. Pretreatment of the cultured gastric smooth muscle cells (GSMCs) with different concentration of CNP can significantly decrease the mSCF expression level. 8-Bromoguanosine-3',5'-cyclomo-nophosphate (8-Br-cGMP), a membrane permeable cGMP analog, mimicked the effect of CNP but not cANF (a specific NPR-C agonist). Methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay showed that high concentration of cANF (10(-6) mol/L) inhibited cell proliferation in cultured GSMCs. These findings suggest that up-regulation of NPs/NPR-A, B/cGMP and NPs/NPR-C signaling pathways may be involved in diabetes-induced loss of gastric ICC.


Assuntos
Diabetes Mellitus Experimental/metabolismo , Trato Gastrointestinal/metabolismo , Células Intersticiais de Cajal/efeitos dos fármacos , Peptídeos Natriuréticos/metabolismo , Animais , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/fisiopatologia , Trato Gastrointestinal/efeitos dos fármacos , Trato Gastrointestinal/patologia , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Células Intersticiais de Cajal/metabolismo , Células Intersticiais de Cajal/patologia , Masculino , Camundongos , Músculo Liso/metabolismo , Peptídeos Natriuréticos/administração & dosagem , Receptores do Fator Natriurético Atrial/metabolismo , Transdução de Sinais/efeitos dos fármacos , Regulação para Cima
10.
PLoS One ; 7(11): e48249, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23133623

RESUMO

PURPOSE: To investigate the role of endogenous hydrogen sulfide (H(2)S) in partial obstruction-induced dysfunction of the interstitial cells of Cajal (ICC) in mice ileum. MATERIALS AND METHODS: Partial intestinal obstruction was induced surgically in male imprinting control region (ICR) mice. ICC networks were studied by Immunohistochemistry. Electrical activity was recorded by intracellular recording techniques. The expression of ICC phenotype marker c-kit receptor tyrosine kinase (c-kit), membrane binding stem cell factor (mSCF), the endogenous H(2)S biosynthesis enzymes cystathionine-ß-synthase (CBS) and cystathionine-γ-lyase (CSE) was studied by Western blotting. The expression of tumor necrosis factor-α (TNF-α) mRNA was observed by using real-time polymerase chain reaction. RESULTS: Partial intestinal obstruction resulted in ICC networks were disrupted above obstruction 14 days after the operation. The slow waves of intestinal smooth muscles in the dilated region were significantly suppressed and their amplitude and frequency were reduced, whilst the resting membrane potentials were depolarized. The expression of c-kit and mSCF was significantly decreased, also suggesting the disruption of the ICC network. The expression of TNF-α was significantly increased in the tunica muscularis of the obstructed intestine. Treatment of cultured intestinal smooth muscle cells with TNF-α caused dramatic down regulation of mSCF. The expression of CBS and CSE was significantly decreased in the tunica muscularis of the obstructed intestine. Intraperitoneal injection (i.p) of DL-propargylglycine, an irreversible inhibitor of CSE, and aminooxyacetic acid, an inhibitor of CBS, elevated the expression of TNF-α mRNA in the tunica muscularis of the ileum. Obstruction-induced over expression of TNF-α was significantly improved by supplementation of NaHS, but not the expressions of mSCF and c-kit. CONCLUSIONS: The down regulation of endogenous H(2)S biosynthesis is related to over expression of TNF-α in obstructed small intestine. TNF-α-mediated mSCF down-regulation is not the only reason of partial intestinal obstruction-induced loss of ICC.


Assuntos
Sulfeto de Hidrogênio/química , Células Intersticiais de Cajal/fisiologia , Obstrução Intestinal/metabolismo , Animais , Cistationina beta-Sintase/biossíntese , Cistationina gama-Liase/biossíntese , Eletrofisiologia/métodos , Imuno-Histoquímica/métodos , Células Intersticiais de Cajal/patologia , Masculino , Camundongos , Camundongos Endogâmicos ICR , Miócitos de Músculo Liso/citologia , Fenótipo , Proteínas Proto-Oncogênicas c-kit/biossíntese , RNA Mensageiro/metabolismo , Ratos , Fator de Células-Tronco/biossíntese , Fator de Necrose Tumoral alfa/biossíntese
11.
Eur J Pharmacol ; 673(1-3): 85-95, 2011 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-22047765

RESUMO

The present study was designed to investigate the effect of endogenous hydrogen sulfide (H2S) on gastric motility in mice. Western blotting and immunocytochemistry were used to determine expression levels of the H2S-producing enzymes cystathionine-ß-synthase (CBS) and cystathionine-γ-lyase (CSE) in gastric tissues and cultured smooth muscle cells. Physiological and intracellular recordings and the whole-cell patch clamp technique were used to evaluate the effect of H2S on the mechanical and electrical activities in muscle strips and in isolated smooth muscle cells, respectively. The results showed that CBS and CSE were expressed in mouse gastric smooth muscle. NaHS, a H2S donor, inhibited the amplitude and frequency of spontaneous contraction at high concentrations (>200 µM). However, NaHS at low concentrations (<100 µM) enhanced the basal tension and increased the contractile amplitude of muscle strips. This excitatory effect was not altered by the blockade of the enteric nerve with TTX, but was abolished by tetraethylammonium (TEA) or 4-aminopyridine (4-AP). Aminooxyacetic acid (AOA), but not propargylglycine (PAG), caused a concentration-dependent inhibition of spontaneous contraction. This effect was restored by L-cysteine and NaHS. In addition, NaHS at low concentrations (<100 µM) produced a depolarization of the membrane potential, whereas AOA hyperpolarized the membrane potential and decreased the amplitude of slow waves. Furthermore, AOA increased whole-cell delayed rectifier K⁺ current (I(K(V))). These findings suggest that endogenous H2S appears to be an excitatory gaseous mediator during physiological regulation of gastric motility and this excitable effect is mediated by depolarization of the membrane potential via inhibition of I(K(V)).


Assuntos
Canais de Potássio de Retificação Tardia/antagonistas & inibidores , Motilidade Gastrointestinal , Sulfeto de Hidrogênio/metabolismo , Sulfetos/farmacologia , Animais , Western Blotting , Cistationina beta-Sintase/metabolismo , Cistationina gama-Liase/metabolismo , Canais de Potássio de Retificação Tardia/metabolismo , Relação Dose-Resposta a Droga , Imuno-Histoquímica , Masculino , Potenciais da Membrana/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos ICR , Miócitos de Músculo Liso/metabolismo , Técnicas de Patch-Clamp , Sulfetos/administração & dosagem
12.
Regul Pept ; 167(2-3): 170-6, 2011 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-21256873

RESUMO

In the present study, we investigated the effect of Ang II on gastric smooth muscle motility and its mechanism using intracellular recording and whole-cell patch clamp techniques. Ang II dose-dependently increased the tonic contraction and the frequency of spontaneous contraction in the gastric antral circular smooth muscles of guinea pig. ZD7155, an Ang II type 1 receptor (AT(1)R) blocker, completely blocked the effect of Ang II on the spontaneous contraction of gastric smooth muscle. In contrast, TTX, a sodium channel blocker, failed to block the effect. Furthermore, nicardipine, a voltage-gated Ca(2+)-channel antagonist, did not block the effect of Ang II on the tonic contraction of gastric smooth muscle, but external free-calcium almost completely blocked this effect. Both ryanodine, an inhibitor of calcium-induced Ca(2+) release (CICR) from ryanodine-sensitive calcium stores, and thapsigargin, which depletes calcium in calcium stores, almost completely blocked the effect of Ang II on tonic contraction. However, 2-APB, an inositol trisphosphate (IP(3)) receptor blocker, significantly, but not completely, blocked the Ang II effect on tonic contraction. We also determined that Ang II depolarized membrane potential and increased slow wave frequency in a dose-dependent manner. It also inhibited delayed rectifying potassium currents in a dose-dependent manner, but did not affect L-type calcium currents or calcium-activated potassium currents. These results suggest that Ang II plays an excitatory regulation in gastric motility via AT(1)R-IP(3) and the CICR signaling pathway. The Ang II-induced inhibition of delayed rectifying potassium currents that depolarize membrane potential is also involved in the potentiation of tonic contraction and the frequency of spontaneous contraction in the gastric smooth muscle of guinea pig.


Assuntos
Angiotensina II/farmacologia , Músculo Liso/fisiologia , Antro Pilórico/fisiologia , Vasoconstritores/farmacologia , Angiotensina II/metabolismo , Animais , Cálcio/metabolismo , Cobaias , Potenciais da Membrana , Contração Muscular/efeitos dos fármacos , Músculo Liso/efeitos dos fármacos , Técnicas de Patch-Clamp , Antro Pilórico/efeitos dos fármacos , Transdução de Sinais , Vasoconstritores/metabolismo
13.
World J Gastroenterol ; 16(1): 48-55, 2010 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-20039448

RESUMO

AIM: To investigate atrial natriuretic peptide (ANP) secretion from gastric mucosa and the relationship between the ANP/natriuretic peptide receptor type A (NPR-A) pathway and diabetic gastroparesis. METHODS: Male imprinting control region (ICR) mice (4 wk old) were divided into two groups: control mice, and streptozotocin-induced diabetic mice. Eight weeks after injection, spontaneous gastric contraction was recorded by using physiography in control and streptozotocin-induced diabetic mice. The ANP-positive cells in gastric mucosa and among dispersed gastric epithelial cells were detected by using immunohistochemistry and flow cytometry, respectively. ANP and natriuretic peptide receptor type A (NPR-A) gene expression in gastric tissue was observed by using the reverse transcriptase polymerase chain reaction. RESULTS: The frequency of spontaneous gastric contraction was reduced from 12.9 +/- 0.8 cycles/min in the control group to 8.4 +/- 0.6 cycles/min in the diabetic mice (n = 8, P < 0.05). However, the amplitude of contraction was not significantly affected in the diabetic group. The depletion of interstitial cells of Cajal in the gastric muscle layer was observed in the diabetic mice. ANP-positive cells were distributed in the gastric mucosal layer and the density index of ANP-positive cells was increased from 20.9 +/- 2.2 cells/field in control mice to 51.8 +/- 2.9 cells/field in diabetic mice (n = 8, P < 0.05). The percentage of ANP-positive cells among the dispersed gastric epithelial cells was increased from 10.0% +/- 0.9% in the control mice to 41.2% +/- 1.0% in the diabetic mice (n = 3, P < 0.05). ANP and NPR-A genes were both expressed in mouse stomach, and the expression was significantly increased in the diabetic mice. CONCLUSION: These results suggest that the ANP/NPR-A signaling pathway is upregulated in streptozotocin-induced diabetic mice, and contributes to the development of diabetic gastroparesis.


Assuntos
Fator Natriurético Atrial/metabolismo , Diabetes Mellitus Experimental/metabolismo , Esvaziamento Gástrico , Mucosa Gástrica/metabolismo , Gastroparesia/etiologia , Receptores do Fator Natriurético Atrial/metabolismo , Transdução de Sinais , Animais , Fator Natriurético Atrial/genética , Glicemia/metabolismo , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/fisiopatologia , Citometria de Fluxo , Gastroparesia/metabolismo , Gastroparesia/fisiopatologia , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Endogâmicos ICR , RNA Mensageiro/metabolismo , Receptores do Fator Natriurético Atrial/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Regulação para Cima
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA