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1.
FASEB J ; 26(6): 2531-7, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22375019

RESUMO

ß-Adrenergic receptor (AR) blockers provide substantial clinical benefits, including improving overall survival and left ventricular (LV) function following myocardial infarction (MI), though the mechanisms remain incompletely defined. The transverse-tubule (T-tubule) system of ventricular myocytes is an important determinant of cardiac excitation-contraction function. T-tubule remodeling occurs early during LV failure. We hypothesized that ß-AR blockers prevent T-tubule remodeling and thereby provide therapeutic benefits. A murine model of MI was utilized to examine the effect of ß-AR blockers on T-tubule remodeling following LV MI. We applied the in situ imaging of T-tubule structure from Langendorff-perfused intact hearts with laser scanning confocal microscopy. We found that MI caused remarkable T-tubule remodeling near the infarction border zone and moderate LV remodeling remote from the MI. Metoprolol and carvedilol administered 6 d after MI for 4 wk each increased the T-tubule integrity at the remote and border zones. At the molecular level, both ß-AR blockers restored border and remote zone expression of junctophilin-2 (JP-2), which is involved in T-tubule organization and formation of the T-tubule/sarcoplasmic reticulum junctions. In contrast, ß-AR blockers had no significant effects on caveolin-3 expression. In summary, our data show that ß-AR antagonists can protect against T-tubule remodeling after MI, suggesting a novel therapeutic mechanism of action for this drug class. Preservation of JP-2 expression may contribute to the beneficial effects of metoprolol and carvedilol on T-tubule remodeling.


Assuntos
Antagonistas Adrenérgicos beta/farmacologia , Infarto do Miocárdio/fisiopatologia , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/fisiologia , Remodelação Ventricular/efeitos dos fármacos , Antagonistas Adrenérgicos beta/uso terapêutico , Animais , Carbazóis/farmacologia , Carvedilol , Caveolina 3/biossíntese , Masculino , Proteínas de Membrana/biossíntese , Metoprolol/farmacologia , Camundongos , Infarto do Miocárdio/tratamento farmacológico , Propanolaminas/farmacologia , Remodelação Ventricular/fisiologia
2.
Front Pharmacol ; 14: 1213215, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37456761

RESUMO

Hemopressin and related peptides have shown to function as the endogenous ligands or the regulator of cannabinoid receptors. The previous studies demonstrated that the endocannabinoid system played important roles in modulating several physiological functions such as sleep, olfaction, emotion, learning and memory, and reward behaviors. Mouse VD-hemopressin (α) [(m)VD-HPα], an 11-residue peptide derived from the α1 chain of hemoglobin, was recently presumed as a selective agonist of the CB1 receptor. The present study was undertaken to investigate the effects of (m)VD-HPα on the sleep-wake cycle and power spectrum of cortical EEG in freely moving rats and the potential neurons in the brain activated by (m)VD-HPα. The results showed that 20.1 nmol of (m)VD-HPα i.c.v. administration increased non-rapid eye movement (NREM) sleep in the first 2 h section accompanied by an increase in EEG delta (0.5-4 Hz) activity. The (m)VD-HPα-induced NREM sleep enhancement was due to extended episode duration instead of the episode number. In addition, the effect of (m)VD-HPα (20.1 nmol) on sleep-wake states was significantly attenuated by an antagonist of the CB1 receptor, AM251 (20 nmol, i.c.v.) but not by the CB2 receptor antagonist, AM630 (20 nmol, i.c.v.). In comparison with vehicle, (m)VD-HPα increased Fos-immunoreactive (-ir) neurons in the ventrolateral preoptic nucleus (VLPO), but reduced Fos-ir neurons in the lateral hypothalamus (LH), tuberomammillary nucleus (TMN), and locus coeruleus (LC). These findings suggest that (m)VD-HPα promotes NREM sleep via the CB1 cannabinoid receptor to probably activate VLPO GABAergic neurons, but inactivates the LH orexinergic, LC noradrenergic, and TMN histaminergic neurons.

3.
Biophys J ; 102(8): L34-6, 2012 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-22768960

RESUMO

TWIK-1 two-pore domain K(+) channels generally produce nonmeasurable or very low levels of K(+) currents in heterologous expression systems under physiologically ionic conditions. Two controversial mechanisms have been proposed to account for this behavior: TWIK-1 K(+) channels are expressed in the cell surface but silenced by sumoylation at a lysine residue (TWIK-1 K274); constitutive and rapid internalization of TWIK-1 causes TWIK-1 channel silencing. Here we report that TWIK-1 K(+) channels heterologously expressed in Chinese hamster ovary cells, which are silent in physiological K(+) gradients, are able to conduct large monovalent cation currents when extracellular ionic conditions change. These results support the hypothesis that TWIK-1 K(+) channels are expressed in the cell surface but silent, and suggest that the TWIK-1 gating behavior rather than the lack of cell surface expression of TWIK-1 results in nondetectable TWIK-1 K(+) currents in heterologous expression systems.


Assuntos
Cátions Monovalentes/metabolismo , Condutividade Elétrica , Inativação Gênica , Canais de Potássio de Domínios Poros em Tandem/deficiência , Canais de Potássio de Domínios Poros em Tandem/genética , Animais , Células CHO , Cricetinae , Cricetulus , Espaço Extracelular/metabolismo , Canais de Potássio de Domínios Poros em Tandem/metabolismo
4.
Circ Res ; 107(4): 520-31, 2010 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-20576937

RESUMO

RATIONALE: The transverse tubule (T-tubule) system is the ultrastructural substrate for excitation-contraction coupling in ventricular myocytes; T-tubule disorganization and loss are linked to decreased contractility in end stage heart failure (HF). OBJECTIVE: We sought to examine (1) whether pathological T-tubule remodeling occurs early in compensated hypertrophy and, if so, how it evolves during the transition from hypertrophy to HF; and (2) the role of junctophilin-2 in T-tubule remodeling. METHODS AND RESULTS: We investigated T-tubule remodeling in relation to ventricular function during HF progression using state-of-the-art confocal imaging of T-tubules in intact hearts, using a thoracic aortic banding rat HF model. We developed a quantitative T-tubule power (TT(power)) index to represent the integrity of T-tubule structure. We found that discrete local loss and global reorganization of the T-tubule system (leftward shift of TT(power) histogram) started early in compensated hypertrophy in left ventricular (LV) myocytes, before LV dysfunction, as detected by echocardiography. With progression from compensated hypertrophy to early and late HF, T-tubule remodeling spread from the LV to the right ventricle, and TT(power) histograms of both ventricles gradually shifted leftward. The mean LV TT(power) showed a strong correlation with ejection fraction and heart weight to body weight ratio. Over the progression to HF, we observed a gradual reduction in the expression of a junctophilin protein (JP-2) implicated in the formation of T-tubule/sarcoplasmic reticulum junctions. Furthermore, we found that JP-2 knockdown by gene silencing reduced T-tubule structure integrity in cultured adult ventricular myocytes. CONCLUSIONS: T-tubule remodeling in response to thoracic aortic banding stress begins before echocardiographically detectable LV dysfunction and progresses over the development of overt structural heart disease. LV T-tubule remodeling is closely associated with the severity of cardiac hypertrophy and predicts LV function. Thus, T-tubule remodeling may constitute a key mechanism underlying the transition from compensated hypertrophy to HF.


Assuntos
Insuficiência Cardíaca/fisiopatologia , Hipertrofia Ventricular Esquerda/fisiopatologia , Microtúbulos/patologia , Remodelação Ventricular/fisiologia , Animais , Aorta Torácica/patologia , Aorta Torácica/fisiopatologia , Progressão da Doença , Acoplamento Excitação-Contração/fisiologia , Insuficiência Cardíaca/patologia , Hipertrofia Ventricular Esquerda/patologia , Masculino , Microscopia Confocal , Microtúbulos/fisiologia , Microtúbulos/ultraestrutura , Ratos , Ratos Sprague-Dawley
5.
Artigo em Inglês | MEDLINE | ID: mdl-36293678

RESUMO

The ontogenetic sleep hypothesis suggested that rapid eye movement (REM) sleep is ontogenetically primitive. Namely, REM sleep plays an imperative role in the maturation of the central nervous system. In coincidence with a rapidly developing brain during the early period of life, a remarkably large amount of REM sleep has been identified in numerous behavioral and polysomnographic studies across species. The abundant REM sleep appears to serve to optimize a cerebral state suitable for homeostasis and inherent neuronal activities favorable to brain maturation, ranging from neuronal differentiation, migration, and myelination to synaptic formation and elimination. Progressively more studies in Mammalia have provided the underlying mechanisms involved in some REM sleep-related disorders (e.g., narcolepsy, autism, attention deficit hyperactivity disorder (ADHD)). We summarize the remarkable alterations of polysomnographic, behavioral, and physiological characteristics in humans and Mammalia. Through a comprehensive review, we offer a hybrid of animal and human findings, demonstrating that early-life REM sleep disturbances constitute a common feature of many neurodevelopmental disorders. Our review may assist and promote investigations of the underlying mechanisms, functions, and neurodevelopmental diseases involved in REM sleep during early life.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade , Transtornos do Sono-Vigília , Animais , Humanos , Sono REM/fisiologia , Sono , Encéfalo/fisiologia
6.
Front Neuroanat ; 16: 968320, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36032994

RESUMO

Recently, researchers have paid progressively more attention to the study of neural development in infant rats. However, due to the lack of complete intracerebral localization information, such as clear nuclear cluster boundaries, identified main brain structures, and reliable stereotaxic coordinates, it is difficult and restricted to apply technical neuroscience to infant rat's brain. The present study was undertaken to refine the atlas of infant rats. As such, we established a stereotaxic atlas of the infant rat's brain at postnatal days 7-13. Furthermore, dye calibration surgery was performed in P7-P13 infant rats by injecting Methylene blue, and sections were incubated in Nissl solutions. From the panoramic images of the brain sections, atlases were made. Our article has provided the appearance and measurements of P7-P13 Sprague-Dawley rat pups. Whereas the atlas contains a series of about 530 coronal brain section images from olfactory bulbs to the brainstem, a list of abbreviations of the main brain structures, and reliable stereotaxic coordinates, which were demonstrated by vertical and oblique injections with fluorescent dye DiI. The present findings demonstrated that our study of P7-P13 atlases has reasonable nucleus boundaries and accurate and good repeatability of stereotaxic coordinates, which can make up for the shortage of postnatal rat brain atlas currently in the field.

7.
Arch Gynecol Obstet ; 281(6): 1023-8, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20033419

RESUMO

PURPOSE: Malignant mixed müllerian tumors (MMMT) of the female genital tract is rare and it is extremely rare in the fallopian tube, with fewer than 53 cases reported in the literature. METHODS: We had experienced two cases of MMMT of the fallopian tube. The clinical features, pathologic findings, diagnosis, therapy, and outcome were reviewed. RESULTS: The clinical features and diagnosis were similar to those of primary carcinoma of the fallopian tube. Histologically, the two patients had homologous and heterologous elements mixed müllerian tumors. Treatment has focused on surgery with postoperative chemotherapy. Prognosis is poor, with fewer than half of patients surviving 2 years. CONCLUSIONS: MMMT of fallopian tube is an uncommon carcinoma in the female genital tract. Cervical cytology and endometrial curettage could raise the suspicion of a tubal malignancy, but diagnosis is not usually made until the time of surgery. The patient survival will improve after surgery and postoperative chemotherapy.


Assuntos
Neoplasias das Tubas Uterinas/diagnóstico , Neoplasias das Tubas Uterinas/terapia , Tumor Mulleriano Misto/diagnóstico , Tumor Mulleriano Misto/terapia , Antineoplásicos/uso terapêutico , Quimioterapia Adjuvante , Neoplasias das Tubas Uterinas/patologia , Feminino , Procedimentos Cirúrgicos em Ginecologia , Humanos , Pessoa de Meia-Idade , Tumor Mulleriano Misto/patologia
8.
Front Psychol ; 11: 2238, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32982893

RESUMO

Ingratiation is regarded as a powerful impression tactic that helps ingratiator achieve their intended goals. Although there is evidence that the consequences of ingratiation are not always positive, little research considers the dark effect of ingratiation on the ingratiator. Based on conservation of resources theory, we develop and test a model that links employees' ingratiation to their counterproductive work behaviors. Data were collected from 216 supervisor-employee dyads. The results of examination with Mplus showed that ingratiation had a positive effect on counterproductive work behaviors, and emotional exhaustion played a mediating role in this relationship. Power distance orientation negatively moderated the relationship between ingratiation and emotional exhaustion and the indirect effect of emotional exhaustion on the relationship between ingratiation and counterproductive work behaviors. Our findings raise attention on the consequences of ingratiation for employees and the dark side of ingratiation for organization.

9.
Asian Pac J Cancer Prev ; 20(6): 1841-1847, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-31244308

RESUMO

Objective: The association between matrix metalloproteinase1 (MMP1)-1607 1G>2G polymorphism and lung cancer risk is still inconclusive and inconsistent. We conducted a meta-analysis to estimate the potential relationship between MMP1-1607 1G>2G polymorphism and lung cancer risk. Methods: The comprehensive searches of the PubMed, Web of Science, Medline, CBM, CNKI, Weipu, and Wanfang databases, published up to Nov 10, 2018. Statistical analyses were performed with Review Manager 5.3 software. Results: A total of 14 relevant studies containing 6068 cases and 5860 controls were included in the study. The results indicated that MMP1-1607 1G>2G polymorphism was significantly associated with increased lung cancer risk under four models: 2G vs. 1G model (pooled OR = 1.19, 95% CI = 1.05-1.34, P < 0.0001); 2G/2G vs. 1G/1G (pooled OR = 1.34, 95% CI = 1.09-1.64, P = 0.003); 2G/2G vs. 1G/1G+1G/2G (pooled OR = 1.26, 95% CI = 1.06-1.49, P < 0.0001); 2G/2G+1G/2G vs. 1G/1G (pooled OR = 1.21, 95% CI = 1.05-1.40, P = 0.01). Subgroup analyses showed that there was a higher increase in smoking status under three models: 2G/2G vs. 1G/1G (pooled OR = 2.07, 95% CI = 1.14-3.77, P = 0.02); 2G/2G vs. 1G/1G+1G/2G (pooled OR = 1.71, 95% CI = 1.17-2.52, P = 0.006); 2G/2G+1G/2G vs. 1G/1G (pooled OR = 2.03, 95% CI = 1.14-3.62, P = 0.02). In addition, subgroup analyses by ethnicity further identified the significant association in Asians. Non-smoking population and ethnicity among Caucasian had no relationship with lung cancer susceptibility in four models. Conclusion: Our study suggested that MMP1-1607 1G>2G polymorphism was a risk factor for developing lung cancer risk.


Assuntos
Predisposição Genética para Doença , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Metaloproteinase 1 da Matriz/genética , Polimorfismo de Nucleotídeo Único , Estudos de Casos e Controles , Humanos , Prognóstico , Fatores de Risco
10.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 27(1): 165-169, 2019 Feb.
Artigo em Zh | MEDLINE | ID: mdl-30738464

RESUMO

OBJECTIVE: To analyze the genotypes and the hematological phenotypic characteristics of α-thalassemia in different areas of Fujian and to evaluate the values of mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), hemoglobin (Hb), RBC distribution width/red blood cell (RDW/RBC) for screening α-thalassemia in this area. METHODS: The Gap-PCR assay was applied for detecting 3 common deletional mutations of patients with α-thalassemia, and the reverse dot-blot (RDB) assay was adopted to detect the foci of 3 common non-deletional gene mutations.Then,the hematological parameters of individuals with α-thalassemia were analyzed. Finally, the optimal cut-off value in hematological indexes for screening α-thalassemia were determined by the ROC curve. RESULTS: Altogether 16 types of gene mutations were found in 772 patients with α-thalassemia. Among them, the -SEA/αα deletion mutation was the most common which was observed in 521 cases(67.49%). Compared with the control group, the differences in MCV, MCH, and Hb were statistically significant between the patients of the same sex but no same type. In male groups, the RDW/RBC ratio was statistically significant in individuals of light type and HbH disease as compared with the healthy control group. But in female groups, the statistical different of RDW/RBC ratio was found between only HbH disease group and control group. MCV<81.25 fl, MCH<27.30 pg, Hb(male)<128.5 g/L, and Hb(female) <123.5 g/L, with the highest specificity and the highest sensitivity, were the best cut-off points for screening α-thalassemia in the laboratory. CONCLUSION: Due to the difference of regional heterogeneity and hospital equipment environment, the different laboratories need to establish cut-off value for screening α-thalassemia suitable for its local region. In future, our laboratory can use MCV<81.25 fl, MCH<27.30 pg, Hb(male)<128.5 g/L, and Hb(female) <123.5 g/L for value for clinical screening, of α-thalassemia.


Assuntos
Talassemia alfa , China , Índices de Eritrócitos , Feminino , Genótipo , Humanos , Masculino , Programas de Rastreamento
13.
World J Clin Cases ; 6(11): 426-440, 2018 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-30294607

RESUMO

AIM: To determine the distribution of rotavirus VP7 gene in hospitalized children in Yunnan, China. METHODS: A total of 366 stool specimens were collected from hospitalized children in hospitals in Yunnan Province from September 2010 to December 2013. The genomic RNA electropherotypes and the G genotypes of the rotaviruses were determined. A phylogenetic analysis of the VP7 gene was performed. Rotavirus isolation was performed, and characterized by plaque, minimum essential medium, and all genes sequence analysis. Quantification of antibodies for inactivated vaccine prepared with ZTR-68 was examined by enzyme-linked immunosorbent assay and microneutralization assay. RESULTS: Group A human rotavirus was detected in 177 of 366 (48.4%) stool samples using a colloidal gold device assay. The temporal distribution of rotavirus cases showed significant correlation with the mean air temperature. Rotaviruses were isolated from 13% of the rotavirus-positive samples. The predominant genotype was G1 (43.5%), followed by G3 (21.7%), G9 (17.4%), G2 (4.3%), G4 (8.7%), and mixed (4.3%) among a total of 23 rotavirus isolates. A rotavirus strain was isolated from a rotavirus-positive stool sample of a 4-month-old child in The First People's Hospital of Zhaotong (2010) for use as a candidate human inactivated rotavirus vaccine strain and for further research, and was designated ZTR-68. The genotype of 11 gene segments of strain ZTR-68 (RVA/Human-wt/CHN/ZTR-68/2010/G1P[8]) was characterized. The genotype constellation of strain ZTR-68 was identified as G1-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1. The VP7 and VP4 genotypes of strain ZTR-68 were similar to Wa-like strains.CONCLUSIONSA high prevalence of the G1, G2, and G3 genotypes was detected from 2010 to 2012. However, a dominant prevalence of the G9 genotype was identified as the cause of gastroenteritis in children in Yunnan, China, in 2013. A candidate human inactivated rotavirus vaccine strain, designated ZTR-68 was isolated, characterized, and showed immunogenicity. Our data will be useful for the future formulation and development of a vaccine in China.

14.
World J Gastroenterol ; 24(45): 5109-5119, 2018 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-30568388

RESUMO

AIM: To establish a rotavirus (RV)-induced diarrhea model using RV SA11 in neonatal rhesus monkeys for the study of the pathogenic and immune mechanisms of RV infection and evaluation of candidate vaccines. METHODS: Neonatal rhesus monkeys with an average age of 15-20 d and an average weight of 500 g ± 150 g received intragastric administration of varying doses of SA11 RV ( 107 PFUs/mL, 106 PFUs/mL, or 105 PFUs/mL, 10 mL/animal) to determine whether the SA11 strain can effectively infect these animals by observing their clinical symptoms, fecal shedding of virus antigen by ELISA, distribution of RV antigen in the organs by immunofluorescence, variations of viral RNA load in the organs by qRT-PCR, histopathological changes in the small intestine by HE staining, and apoptosis of small intestinal epithelial cells by TUNEL assay. RESULTS: The RV monkey model showed typical clinical diarrhea symptoms in the 108 PFUs SA11 group, where we observed diarrhea 1-4 d post infection (dpi) and viral antigen shed in the feces from 1-7 dpi. RV was found in jejunal epithelial cells. We observed a viral load of approximately 5.85 × 103 copies per 100 mg in the jejunum at 2 dpi, which was increased to 1.09 × 105 copies per 100 mg at 3 dpi. A relatively high viral load was also seen in mesenteric lymph nodes at 2 dpi and 3 dpi. The following histopathological changes were observed in the small intestine following intragastric administration of SA11 RV: vacuolization, edema, and atrophy. Apoptosis in the jejunal villus epithelium was also detectable at 3 dpi. CONCLUSION: Our results indicate that we have successfully established a RV SA11 strain diarrhea model in neonatal rhesus monkeys. Future studies will elucidate the mechanisms underlying the pathogenesis of RV infection, and we will use the model to evaluate the protective effect of candidate vaccines.


Assuntos
Diarreia/imunologia , Modelos Animais de Doenças , Macaca mulatta , Infecções por Rotavirus/imunologia , Rotavirus/patogenicidade , Animais , Animais Recém-Nascidos , Diarreia/diagnóstico , Diarreia/virologia , Células Epiteliais/imunologia , Células Epiteliais/patologia , Células Epiteliais/virologia , Fezes/virologia , Humanos , Intestino Delgado/citologia , Intestino Delgado/imunologia , Intestino Delgado/patologia , Intestino Delgado/virologia , RNA Viral/isolamento & purificação , Rotavirus/genética , Rotavirus/imunologia , Infecções por Rotavirus/diagnóstico , Infecções por Rotavirus/virologia , Eliminação de Partículas Virais
16.
Oncol Lett ; 11(2): 1125-1129, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26893704

RESUMO

Desmoplastic small round cell tumors (DSRCTs) were initially characterized as exhibiting divergent differentiation and were extremely aggressive, belonging to the family of 'small round blue cell tumors'. Due to a male predominance, to date, only 15 cases in women have been reported in the English literature. The present study describes a case of DSRCT in a young woman who initially presented with ovarian masses accompanied with lymph node and lung metastases. A correct diagnosis was reached by combining the hematoxylin and eosin, and immunohistochemical staining results. Following surgery, the patient underwent the chemotherapy and, 3 months later, is in a good condition. The study also provides an overview of this uncommon disease.

17.
Asian Pac J Cancer Prev ; 17(3): 1141-8, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27039739

RESUMO

BACKGROUND: A large number of studies have been published to investigate the association between the null genotype of glutathione S-transferase T1 (GSTT1) with gastric cancer. However, the results were inconsistent and conflicting. The aim of this study was to estimate the relationship between this polymorphism in the GSTT1 gene and gastric cancer risk in Asian populations by meta-analysis. MATERIALS AND METHODS: A literature search was performed in PubMed, Embase, Chinese Biomedical database (CBM), Weipu database, Wanfang database, and China National Knowledge Infrastructure database (CNKI). Statistical analysis was conducted by using Review Manager 5.3. RESULTS: Thirty-nine studies with a total of 7,737 gastric cancer cases and 10,823 controls were included in this meta-analysis. The meta-analysis of total studies showed that the null genotype in GSTT1 was associated with increased risk of gastric cancer in Asians (OR=1.19, 95% CI=1.08-1.31, p=0.0002). Subgroup analysis showed a significant relationship between GSTT1 null genotype and gastric cancer in East-Asians, as well as in subgroup analysis of hospital-based design. On subgroup analysis by smoking status, alcohol status, Helicobacter pylori infection status, and histology type, no significant association of this polymorphism with susceptibility to gastric cancer was found. CONCLUSIONS: In conclusion, the results showed that the null genotype of GSTT1 is significantly associated with an increased risk in gastric cancer in Asian populations.


Assuntos
Predisposição Genética para Doença , Glutationa Transferase/genética , Polimorfismo Genético/genética , Neoplasias Gástricas/genética , Ásia/epidemiologia , Estudos de Casos e Controles , Humanos , Prognóstico , Fatores de Risco , Neoplasias Gástricas/epidemiologia
19.
Circ Arrhythm Electrophysiol ; 5(4): 841-9, 2012 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-22722659

RESUMO

BACKGROUND: Catecholaminergic polymorphic ventricular tachycardia is directly linked to mutations in proteins (eg, type 2 ryanodine receptor [RyR2](R4496C)) responsible for intracellular Ca(2+) homeostasis in the heart. However, the mechanism of Ca(2+) release dysfunction underlying catecholaminergic polymorphic ventricular tachycardia has only been investigated in isolated cells but not in the in situ undisrupted myocardium. METHODS AND RESULTS: We investigated in situ myocyte Ca(2+) dynamics in intact Langendorff-perfused hearts (ex vivo) from wild-type and RyR2(R4496C+/-) mice using laser scanning confocal microscopy. We found that myocytes from both wild-type and RyR2(R4496C+/-) hearts displayed uniform, synchronized Ca(2+) transients. Ca(2+) transients from beat to beat were comparable in amplitude with identical activation and decay kinetics in wild-type and RyR2(R4496C+/-) hearts, suggesting that excitation-contraction coupling between the sarcolemmal Ca(2+) channels and mutated RyR2(R4496C+/-) channels remains intact under baseline resting conditions. On adrenergic stimulation, RyR2(R4496C+/-) hearts exhibited a high degree of Ca(2+) release variability. The varied pattern of Ca(2+) release was absent in single isolated myocytes, independent of cell cycle length, synchronized among neighboring myocytes, and correlated with catecholaminergic polymorphic ventricular tachycardia. A similar pattern of action potential variability, which was synchronized among neighboring myocytes, was also revealed under adrenergic stress in intact hearts but not in isolated myocytes. CONCLUSIONS: Our studies using an in situ confocal imaging approach suggest that mutated RyR2s are functionally normal at rest but display a high degree of Ca(2+) release variability on intense adrenergic stimulation. Ca(2+) release variability is a Ca(2+) release abnormality, resulting from electric defects rather than the failure of the Ca(2+) release response to action potentials in mutated ventricular myocytes. Our data provide important insights into Ca(2+) release and electric dysfunction in an established model of catecholaminergic polymorphic ventricular tachycardia.


Assuntos
Sinalização do Cálcio , Microscopia Confocal , Mutação , Miócitos Cardíacos/metabolismo , Canal de Liberação de Cálcio do Receptor de Rianodina/genética , Taquicardia Ventricular/metabolismo , Potenciais de Ação , Agonistas Adrenérgicos/farmacologia , Animais , Sinalização do Cálcio/efeitos dos fármacos , Modelos Animais de Doenças , Eletrocardiografia , Epinefrina/farmacologia , Acoplamento Excitação-Contração , Predisposição Genética para Doença , Técnicas In Vitro , Cinética , Camundongos , Camundongos Mutantes , Contração Miocárdica , Miócitos Cardíacos/efeitos dos fármacos , Perfusão , Fenótipo , Taquicardia Ventricular/genética , Taquicardia Ventricular/fisiopatologia
20.
Hypertension ; 59(2): 355-62, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22203744

RESUMO

Right ventricular (RV) failure (RVF) is the main cause of death in patients with pulmonary artery hypertension (PAH). Sildenafil, a phosphodiesterase type 5 inhibitor, was approved recently for treatment of PAH patients. However, the mechanisms underlying RV contractile malfunction and the benefits of sildenafil on RV function are not well understood. We aimed to investigate the following: (1) the ultrastructural and excitation-contraction coupling alterations underlying PAH-induced RVF; (2) whether the ultrastructural changes are reversible; and (3) the mechanisms underlying the therapeutic benefits of sildenafil in PAH-RVF. We used a single injection of monocrotaline in Wistar rats to induce pulmonary vascular proliferation, which led to PAH and RVF. RV myocytes displayed severe transverse (T)-tubule loss and disorganization, as well as blunted and dys-synchronous sarcoplasmic reticulum Ca(2+) release. Sildenafil prevented and reversed the monocrotaline-induced PAH and LV filling impairment. Early intervention with sildenafil prevented RV hypertrophy and the development of RVF, T-tubule remodeling, and Ca(2+) handling dysfunction. Although late treatment with sildenafil did not reverse RV hypertrophy in animals with established RVF, RV systolic function was improved. Furthermore, late intervention partially reversed both the impairment of myocyte T-tubule integrity and Ca(2+) handling protein and sarcoplasmic reticulum Ca(2+) release function in monocrotaline-treated rats. In conclusion, PAH-induced increase in RV afterload causes severe T-tubule remodeling and Ca(2+) handling dysfunction in RV myocytes, leading to RV contractile failure. Sildenafil prevents and partially reverses ultrastructural, molecular, and functional remodeling of failing RV myocytes. Reversal of pathological T-tubule remodeling, although incomplete, is achievable without the regression of RV hypertrophy.


Assuntos
Cálcio/metabolismo , Insuficiência Cardíaca/prevenção & controle , Hipertensão Pulmonar/complicações , Miócitos Cardíacos/patologia , Piperazinas/farmacologia , Piperazinas/uso terapêutico , Sulfonas/farmacologia , Sulfonas/uso terapêutico , Disfunção Ventricular Direita/prevenção & controle , Remodelação Ventricular/efeitos dos fármacos , Animais , Modelos Animais de Doenças , Acoplamento Excitação-Contração/efeitos dos fármacos , Acoplamento Excitação-Contração/fisiologia , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/fisiopatologia , Hipertensão Pulmonar/induzido quimicamente , Hipertensão Pulmonar/fisiopatologia , Hipertrofia Ventricular Direita/etiologia , Hipertrofia Ventricular Direita/fisiopatologia , Hipertrofia Ventricular Direita/prevenção & controle , Masculino , Microscopia Confocal , Monocrotalina/efeitos adversos , Contração Miocárdica/efeitos dos fármacos , Contração Miocárdica/fisiologia , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Inibidores da Fosfodiesterase 5/farmacologia , Inibidores da Fosfodiesterase 5/uso terapêutico , Purinas/farmacologia , Purinas/uso terapêutico , Ratos , Ratos Wistar , Citrato de Sildenafila , Resultado do Tratamento , Disfunção Ventricular Direita/etiologia , Disfunção Ventricular Direita/fisiopatologia , Remodelação Ventricular/fisiologia
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