[show abstract][hide abstract] ABSTRACT: The major structure elements of the AMP-activated protein kinase (AMPK) are α, β, and γ sunbunits. Mutations in γ2 subunit (PRKAG2) have been associated with a cardiac syndrome including inherited ventricular preexcitation, conduction disorder and hypertrophy mimicking hypertrophic cardiomyopathy. The aim of the present study was to identify PRKAG2 syndrome among patients presenting with left ventricular hypertrophy (LVH).
Nineteen unrelated subjects with unexplained LVH were clinically and genetically evaluated. Among 4 patients with bradycardia, manifestations of preexcitation were only found in a 19 year old male who also developed congestive heart failure 3 years later. Electrophysiological study of this case identified the coexistence of an AV accessory pathway and AV conduction defect. Histological analysis of his ventricular tissue isolated by biopsy confirmed excessive glycogen accumulation, prominent myofibrillar disarray and interstitial fibrosis. Direct sequencing of his DNA revealed a heterozygous mutation in PRKAG2 consisting of an A-to-G transition at nucleotide 1453 (c.1453A>G), predicting a substitution of a glutamic acid for lysine at highly-conserved residue 485 (p.Lys485Glu, K485E), which was absent in his unaffected family members and in 215 healthy controls. To assess the role of K485 in the structure and function of the protein, computational modeling calculations and conservation analyses were performed. Electrostatic calculations indicate that K485 forms a salt bridge with the conserved D248 residue in the AMPK β subunit, which is critical for proper regulation of the enzyme, and the K485E mutant disrupts the connection.
Our study identifies a novel de novo PRKAG2 mutation in a young, in which progression of the disease warrants close medical attention. It also underlines the importance of molecular screening of PRKAG2 gene in patients with unexplained LVH, ventricular preexcitation, conduction defect, and/or early onset of heart failure.
PLoS ONE 01/2013; 8(5):e64603. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: To observe the inhibitory effect of cyclin-dependent kinase inhibitor p21 on regulation of survivin transcription in human liver cancer HepG cells, and explore the related mechanisms.
Doxorubicin (DOX) was used to treat HepG cells. Eukaryotic vector pEGFP-C2-p21 was transfected into HepG cells by lipofectamine and positive clones were screened out by G418. The mRNA expression of p21, p53 and survivin were detected by real-time fluorescent quantitative polymerase chain reaction (RQ-PCR). Flow cytometry was used to determine the cell cycle phases, and reverse transcription polymerase chain reaction (RT-PCR) was used to measure the levels of E2F-1 or p300.
After treatment with DOX, the expression of p53 and p21 was increased, whereas that of survivin was reduced during 24 hours of the treatment. After transfection the p21 level was 2100.1-fold or 980.9-fold enhanced in comparison with that in HepG2 cells or HepG2-pEGFP cells. Survivin level was markedly down-regulated to 0.5% or 0.6% relative to that in the other two groups, nevertheless, significant p53 changes were not observed. Overexpression of p21 resulted in G1/G0 phase arrest (F = 31.59, P < 0.01), meanwhile, E2F-1 mRNA or p300 mRNA were less expressed compared with that in the other controls (F(E2F-1) = 125.28, P < 0.05; Fp300 = 46.01, P < 0.01).
p21 could be a potential mediator of survivin suppression at transcription level in HepG2 cells, which might be through the block at G1/G0 phase and down-regulation of transcription factors E2F-1 and p300.
Zhonghua zhong liu za zhi [Chinese journal of oncology] 08/2008; 30(8):583-7.
[show abstract][hide abstract] ABSTRACT: Chemotherapy protocols using adriamycin (ADM) is a standard treatment for hepatoblastoma, but the treatment results became unsatisfied because of drug resistance. Recently, ADM combined gene therapy is a developing alternative treatment for hepatoblastoma. This study was to investigate the effect of ADM combined human p21CIP1 transfection on the proliferation of hepatoblastoma cell line HepG2.
HepG2 cells were divided into empty control group (no treatment), ADM group (treated with 0.5 microg/mL ADM), blank control group (transfected with blank plasmid pcDNA3), p21 group (transfected with plasmid pcDNA3-p21), and combination group (ADM treatment plus p21 transfection). The proliferation of HepG2 cells was observed by MTT assay. The mRNA levels of p21 and survivin were detected by real-time polymerase chain reaction (PCR).
After transfection, the mRNA level of p21 in p21 group was increased by 155 folds of that in empty control group (P<0.05). p21 inhibited the proliferation of HepG2 cells at Day 3 and Day 4 after transfection (P<0.01). The proliferation inhibition rate was significantly higher in combination group than in ADM group and p21 group (43.92% vs. 32.97% and 35.77% at Day 3, P<0.01; 59.86% vs. 39.35% and 40.96% at Day 4, P<0.01; 51.81% vs. 33.91% and 10.68% at Day 5, P<0.01). This effect was enhanced along with the increasing time of co-treatment from Day 1 to Day 4 (r=0.91, P<0.05), and it was obvious at Day 4 (Q =1.07). The mRNA level of survivin was significantly lower in combination group than in p21 group and ADM group (P<0.01).
p21 gene transfection plus ADM can inhibit the proliferation of HepG2 cells and down-regulate the level of survivin mRNA, thus may be a potential therapeutic strategy against human hepatoblastoma.
Ai zheng = Aizheng = Chinese journal of cancer 05/2008; 27(5):476-81.
[show abstract][hide abstract] ABSTRACT: To investigate the single nucleotide polymorphisms (SNPs) of -1516G/T in the promoter region and 4259G/T in the exon-3 region of the T cells immunoglobulin mucin-3 (TIM-3) and their linkage disequilibrium, and therefore to detect their haplotype relationship with allergic asthma of the Han population from Hubei province of China.
The two polymorphisms were detected with allelic specific polymerase chain reaction (ASPCR). In the 175 asthmatic subjects and in the 202 healthy controls collected from June, 2004 to October 2007 in the Han population from Hubei province. The genotype and allele frequencies, the D' value between the two SNPs sites, the haplotype and their frequencies were calculated and analyzed, respectively.
The genotype frequencies of GG, GT and TT in -1516G/T polymorphism of TIM-3 gene were 82.7% (167/202), 17.3% (35/202), 0 (0/202) respectively in the 202 controls, and 82.9% (145/175), 17.1% (30/175), 0 (0/175) respectively in the 175 asthmatic subjects. The genotype frequencies of GG, GT and TT in 4259G/T polymorphism of TIM-3 gene were 0.5% (1/202), 2.5% (5/202), 97.0% (196/202) respectively in the 202 controls and 0.6% (1/175), 5.7% (10/175), 93.7% (164/175) respectively in the 175 asthmatic subjects. The control group: D' = 1.0, the asthma group D' = 0. 9. The 3 haplotypes were G-G, G-T, T-T in the Han population from Hubei province of China, and their haplotype frequencies were distributed similarly in asthma 3.4% (12/350), 88.0% (308/ 350), 8.6% (30/350) and in the controls 1.7% (7/404), 89.6% (362/404), 8.7% (35/404). None of these differences were statistically significant (chi2 = 2.15, 0.47, 0.003 respectively, all P > 0.05).
There are strong linkage disequilibrium between the two SNPs sites in TIM-3 gene in Han population from Hubei province, but the haplotypes G-G, G-T and T-T are not associated with asthma susceptibility of this population. We cannot exclude the possibility that the haplotypes of TIM-3 may be associated with asthma susceptibility in other ethnic populations or the susceptibility to other atopic diseases and autoimmunity diseases.
Zhonghua jie he he hu xi za zhi = Zhonghua jiehe he huxi zazhi = Chinese journal of tuberculosis and respiratory diseases 04/2008; 31(3):196-200.
[show abstract][hide abstract] ABSTRACT: To investigate the frequencies of -1516,-574 and 4259 single nucleotide polymorphisms (SNPs) of T cells immunoglobulin mucin -3(TIM-3) gene in Hubei population and address the question whether they are in linkage disequilibrium(LD) .
Genotypes and allele frequencies of TIM-3 gene were examined by allele-specific polymerase chain reaction (AS-PCR) methods in 147 healthy Hubei Han individuals. Hardy-Weinberg equilibrium and Two-point LD analyses and haplotype frequencies were evaluated with Arlequin v3.1 software.
The allele frequencies of the 3 SNPs were in agreement with Hardy-Weinberg equilibrium. Minor allelic frequencies of TIM-3 -1516G/T,-574T/G and 4259G/T were 8.5%,1.0% and 2.0%,respectively. The dominant haplotypes comprising the three loci were G-G-G(2.0%),G-G-T(88.4%), T-G-T(8.5%) and G-T-T(1.0%). LD analyses revealed that all of the coefficient of linkage disequilibrium (D') were 1.
The -1516,-574 and 4259 loci of TIM-3 gene are in complete linkage disequilibrium. Our study has provided population genetic data on TIM-3 gene in Chinese Hubei Han population and a basis for searching immune-mediated disease-related TIM-3 haplotype.
Zhonghua yi xue yi chuan xue za zhi = Zhonghua yixue yichuanxue zazhi = Chinese journal of medical genetics 03/2008; 25(1):101-4.
[show abstract][hide abstract] ABSTRACT: To observe the effects of aspirin on nuclear factor kappaB (NF-kappaB)-DNA binding activity and on the expression of cyclooxygenase-2 (COX-2) in atherosclerotic plaque so as to explore its antiatherosclerotic mechanism.
Thirty-six New Zealand male rabbits were randomly divided into 3 equal groups: high-cholesterol (HC) group, fed with food high in cholesterol and perfused into the empty stomach daily with distilled water for 12 weeks, high-cholesterol and aspirin (HC + A) group, fed with food high in cholesterol and perfused into the empty stomach daily with aspirin solution, and normal control (NC) group, fed with normal food and perfused into the empty stomach daily with distilled water, before the experiment, and 4, 8, and 12 weeks after the beginning of experiment peripheral blood samples were collected. The serum lipids were detected with enzymatic assays; and enzyme-linked immunosorbent assay was used to detect the level of high sensitive C-reactive protein (hs-CRP). By the end of experiment the rabbits were killed to take out the specimens of aorta to observe the neointima thickness and plaque area of aorta. Electrophoretic mobility shift assay was used to detect the NF-kappaB-DNA binding activity, and immunohistochemistry and morphometry were performed to observe the expression of COX-2 protein, the neointima thickness and plaque area of aorta respectively in all three groups.
The levels of serum lipids, hs-CRP, NF-kappaB-DNA binding activity, expression of COX-2 protein, and neointima thickness and plaque area of aorta in the HC and HC + A groups were all significantly higher than those in the NC group (P < 0.05 -0.01). There was no significant differences in the serum lipids between the HC and HC + A groups (all P > 0.05), however, the levels of hs-CRP, NF-kappaB-DNA binding activity, expression of COX-2 protein, and neointima thickness and plaque area of aorta of the HC + A group were (5.14 +/- 0.32) microg/ml, (14.6 +/- 2.7) microg/ml, (0.342 +/- 0.02)A, (165 +/- 24) microm, and (24.3 +/- 7.6)% respectively, all significantly lower than those of the HC group [(9.39 +/- 0.79) microg/ml, (32.4 +/- 4.7) microg/ml, (0.572 +/- 0.061) A, (337 +/- 64) microm, and (49.5 +/- 21.3)%, all P < 0.05). By reducing the expression of COX-2.
[show abstract][hide abstract] ABSTRACT: This study was purposed to construct and identify the mammalian expression vector of pEGFP-BMI-1 and to detect whether it could express in human cervix cancer cell line HeLa. The cDNA fragment of BMI-1 obtained by RT-PCR was inserted into pEGFP-N1. The recombinant plasmid was confirmed by restriction enzyme digestion, PCR and DNA sequencing. pEGFP-BMI-1 was transfected into HeLa cells with lipofectamine 2000. The expression of pEGFP-BMI-1 was determined by EGFP fluorescence and Western blot analysis. SYBR Green I real-time RT-PCR was used to quantitate P16INK4a mRNA. The results showed that the correct construction of the recombinant plasmid pEGFP-BMI-1 has been shown by restriction enzyme digestion, PCR and DNA sequencing. pEGFP-BMI-1 could express BMI-1-EGFP fusion protein in HeLa cells. Real-time RT-PCR showed that P16INK4a mRNA expression was reduced to 9.2%. It is concluded that the vector of pEGFP-BMI-1 has been successfully constructed and it can be expressed in HeLa cells. This work has laid foundations for further study on biological functions and potential application of BMI-1.
Zhongguo shi yan xue ye xue za zhi / Zhongguo bing li sheng li xue hui = Journal of experimental hematology / Chinese Association of Pathophysiology 11/2007; 15(5):1056-60.
[show abstract][hide abstract] ABSTRACT: In order to confirm the hypothesis that during acute hypoxia, the antiarrhythmic peptide (AAP10) could improve conductance by changing the phosphorylation state of connexin43 (Cx43), isolated perfused rat hearts were randomly divided into three groups: control, hypoxia and AAP10 (n=9 in each group). The change in Cx43 phosphorylation was tested by Western-blot; the distribution of Cx43 was observed by confocal immunofluorescence microscopy. Western-blot analysis revealed that the expression of total Cx43 protein was significantly decreased during acute hypoxia, while nonphosphorylated Cx43 (NP-Cx43) was unchanged. AAP10 could increase the expression of total Cx43 protein, but had no effects on the NP-Cx43 protein. Immunofluorescence study showed that during acute hypoxia, both total Cx43 and NP-Cx43 proteins were greatly decreased, while AAP10 only increased the expression of total Cx43 protein, but had no effect of the NP-Cx43 protein expression. These findings suggested that the decrease of intercellular communication may be associated with the reduction of phosphorylated Cx43 (p-Cx43) and translocation of NP-Cx43 from the surface of gap junction into intracellular pools during acute hypoxia. AAP10 can improve intercellular communication by enhancing phosphorylation of Cx43.
Journal of Huazhong University of Science and Technology 07/2007; 27(3):241-4. · 0.58 Impact Factor
[show abstract][hide abstract] ABSTRACT: A plasmid carrying DNA to be transcribed into a small interfering RNA against transketolase-like-1 mRNA was constructed and transfected into a human colon cancer cell line. The mRNA expression of transketolase gene family in the human colon cell line was determined by real-time polymerase chain reaction. The effect of anti-transketolase-like-1 small interfering RNA on cell proliferation and cell cycle in the human colon cancer cell line cells was detected by flow cytometry and 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium bromide. The transketolase-like-1 gene was significantly downregulated in human colon cancer cell line cells transfected with small interfering RNA transketolase-like-1 constructs compared with the cells transfected with control vector and the cells without transfection. In addition, the anti-transketolase-like-1 small interfering RNA construct significantly decreased the level of transketolase in the transfected human colon cancer cell line cells, arrested them in G0/G1 phase and substantially inhibited cell proliferation. No significant difference was found in the other two genes (transketolase and transketolase-like-2 genes) between the transfected human colon cancer cell line cells and the controls (P>0.05). Our data demonstrated that the transketolase-like-1 gene plays an important role in total transketolase activity and in the cell proliferation of human colon cancer. Transketolase-like-1 may serve as a target for novel anticancer therapies.
[show abstract][hide abstract] ABSTRACT: Beta-catenin plays a central role in Wnt signaling pathway. The aberrant localization of beta-catenin in nucleus causes the transcription of down-stream target genes, which is the pathogenesy of some solid tumours. As the expression of adheren junction on hemopoietic cells is very low, there are a few studies on beta-catenin expression in leukaemia. This study was aimed to investigate beta-catenin localization and beta-catenin mRNA expression levels in 4 leukemia cell lines so as to explore a new oncogenic mechanism and to find out a new therapeutic target. The beta-catenin localization in leukemia cell lines was detected by immunocytochemistry, the beta-catenin mRNA expression level was assayed by real-time quantitative RT-PCR. The results showed that there was aberrant localization of beta-catenin in Jurkat and Thp-1, and beta-catenin mRNA expression level was not increased in these two cell lines, however, the mRNA expression levels of Jurkat and Thp-1 were lower than those of Daudi and K562. The beta-catenin mRNA expression level was not correlated with beta-catenin aberrant localization in these 4 cell lines. It is concluded that the aberrant localization of beta-catenin may play a role in the development of some leukemia, and the mechanism resulting in beta-catenin aberrant localization not take place at transcription level.
Zhongguo shi yan xue ye xue za zhi / Zhongguo bing li sheng li xue hui = Journal of experimental hematology / Chinese Association of Pathophysiology 01/2007; 14(6):1096-100.
[show abstract][hide abstract] ABSTRACT: Malignant ventricular arrhythmias can arise in a subset of congestive heart failure (CHF) patients after they undergo cardiac resynchronization therapy (CRT), thus counteracting the haemodynamic benefits typically associated with biventricular pacing. This study seeks to assess whether alteration of the ventricular transmural repolarization and conduction due to reversal of the depolarization sequence during epicardial or biventricular pacing facilitate the development of ventricular arrhythmias.
ECGs and monophasic action potential (MAP) were recorded during programmed stimulation from right ventricle (RV) endocardium (RV-Endo), left ventricle (LV) epicardium (LV-Epi), or both (biventricular, Bi-V) in 15 individuals without structural heart diseases. In patients with severe CHF and CRT (n=21), ECGs were collected during RV-Endo, LV-Epi, and Bi-V pacing. MAP duration on intracardiac electrogram, the QT, JT, and T(peak)-T(end) intervals on ECGs at different pacing sites were measured and compared. In subjects with or without structural heart disease, compared with RV-Endo pacing, LV-Epi and Bi-V pacing resulted in a longer JT (341.78+/-61.97 ms with LV-Epi, 325.86+/-59.69 ms with Bi-V vs. 286.14+/-38.68 ms with RV-Endo in CHF individuals, P<0.0001) or T(peak)-T(end) interval (121.55+/-19.88 ms with LV-Epi, 117.71+/-42.63 ms with Bi-V vs. 102.28+/-12.62 ms with RV-Endo in normal-heart subjects, P<0.0001; 199.70+/-62.44 ms with LV-Epi, 184.89+/-74.08 ms with Bi-V vs. 146.41+/-31.06 ms with RV-Endo in CHF patients, P<0.0001), in addition to prolonged myocardial repolarization time and delayed endocardial activation. During follow-up, sudden death and arrhythmia storm occurred in two CHF patients after CRT.
Epicardial and biventricular pacing prolong the time and increase the dispersion of myocardial repolarization and delay the transmural conduction. All of these should be considered as potential arrhythmogenic factors in CHF patients who receive CRT.
[show abstract][hide abstract] ABSTRACT: To evaluate the effects of antiarrhythmic peptide (AAP10) on ventricular arrhythmias in rabbits with healed myocardial infarction (OMI).
Thirty rabbits were randomly divided into three groups (n = 10 each): Sham group, left thoracotomy was performed without coronary ligation; OMI group and OMI + AAP10 group, the circumflex coronaries were ligated. Three months post operation, the electrophysiological and antiarrhythmic effects of AAP10 were assessed in the arterially perfused rabbit left ventricular wedge preparation. Sham and OMI group were perfused with Tyrode's solution and OMI + AAP10 group was perfused with Tyrode's solution + AAP10 (80 nmol/L). Transmembrane action potentials were recorded simultaneously from endocardium and epicardium together with a transmural ECG by use of 2 separate intracellular floating microelectrodes. The stimulus-response-interval (SRI) of the epicardium and the incidence of ventricular tachycardia (VT) were observed. Whole heart and left ventricular weights, the left ventricular thickness at infarct border zone were measured.
Whole heart and left ventricular weights as well as the left ventricular thickness at the infarct border zone significantly increased post infarction. VT was induced in 8 out of 10 rabbits in OMI group and in 2 out of 10 rabbits in OMI + AAP10 group (P < 0.05). SRI was also significantly shortened in OMI + AAP10 group compared to OMI group [SRI-1: (20.59 +/- 0.79) ms vs. (28.71 +/- 0.55) ms; SRI-2: (30.42 +/- 0.74) ms vs. (38.67 +/- 0.49) ms, all P < 0.01]. However, the action potential morphology and duration were similar between OMI and OMI + AAP10 groups.
The antiarrhythmic peptide (AAP10) can increase gap junctional intercellular conductance without affecting the action potential morphology and duration and decrease the incidence of inducible ventricular tachycardia.
Zhonghua xin xue guan bing za zhi [Chinese journal of cardiovascular diseases] 09/2006; 34(9):825-8.
[show abstract][hide abstract] ABSTRACT: The present study retrospectively evaluated the reliability of detecting atrial tachyarrhythmias (ATA), the efficacy of automatic atrial antitachycardia pacing (ATP) and the performance of atrial preventive pacing (APP) algorithms in an implanted antitachycardia DDDRP pacemaker for patients with sick sinus syndrome and paroxysmal ATA.
In all 24 patients, a DDDRP pacemaker (Medtronic AT500/AT501) was implanted. APP algorithms were switched on at the implanting physician's discretion. During each pacemaker follow-up, information was saved to disk and the ATA burden between those patients with APP algorithms switched "ON" and "OFF" were compared. Reliability of ATA detection was determined by reviewing the stored electrograms and ATP efficacy was also reviewed. Both the pacemaker memory data and manual EGM retrieval were used for the analysis.
Complication-free survival at (17.63 +/- 8.79) months was 100%. In 12 patients APP was not turned "ON" until the latest follow-up, in 6 patients APP was switched "ON" at their first visit after implantation, and in another 6 patients APP was switched "ON" after a median follow-up of 9.29 months. There were 97 367 episodes of ATA detected by the devices, of those with stored atrial electrograms the correct classification of ATA was (76.77 +/- 20.52)%. The percentage of atrial pacing with APP algorithms turned on was (87.95 +/- 20.93)%, which was significantly higher than that in patients with APP "OFF" (50.73 +/- 34.46)% (P < 0.01). ATP efficacy was (50.27 +/- 19.29)%. However, the ATA burden (14.73% vs 16.52%, or 7.52 hours vs 6.58 hours per week, P > 0.05) and the longest duration of single ATA episode (27.27 hours vs 20.75 hours, P > 0.05) were not significantly different between those patients with APP "ON" and "OFF". No proarrhythmic effect or major cardiovascular event was observed.
The antitachycardia DDDRP pacemaker correctly detects and diagnoses about 75% of the ATA episodes, while the ATP therapy successfully terminates atrial tachycardia or flutter in about 50% of attacks. However, there is no difference in ATA burden with the APP algorithms and high incidence of atrial pacing. As a non-curative therapy strategy, this high-cost device may only be used in strictly selected indication patients in addition to other treatments of ATA.
Zhonghua xin xue guan bing za zhi [Chinese journal of cardiovascular diseases] 04/2006; 34(4):333-7.
[show abstract][hide abstract] ABSTRACT: In this study, we examined the effects of aspirin on the growth rates, subcellar distribution of beta-catenin protein, the expression of beta-catenin/TCF signaling pathway target gene cyclinD1 mRNA, and cell cycle of Jurkat cell line (Human T-acute lymphoblastic leukemia). Our results showed that the treatment with aspirin inhibited the growth of Jurkat cell line. Jurkat cells treated with 3 mmol/L of aspirin could significantly decrease nuclear localization of beta-catenin, and at 5 mmol/L of aspirin, the nuclear localization of beta-catenin was undetectable. QRT-PCR showed that the target gene cyclinD1 mRNA expression was gradually decreased with the dosage of aspirin. Aspirin induced G0/G1 cell cycle arrest in Jurkat cells. We are led to conclude that aspirin acts through beta-catenin-independent mechanisms. The effects of aspirin include down-regulation of beta-catenin nuclear localization and G0/G1 cell cycle arrest, which might serve as a means of growth inhibition in aspirin-treated human Jurkat cell line.
Journal of Huazhong University of Science and Technology 02/2006; 26(6):731-4. · 0.58 Impact Factor
[show abstract][hide abstract] ABSTRACT: The effects of amiodarone on transmural dispersion of ventricular effective refractory periods (ERPs) in the normal and hypertrophic canine heart were investigated in vivo. By using the programmed stimulation protocol, the ERPs of epicardium (Epi), midmyocardium (Mid) and endocardium (Endo) were measured by inserting specially-designed electrodes into the three myocardial layers before and after mainlining of amiodarone. No significant ERPs-dispersion was observed in the three layers before and after mainlining of amiodarone in the normal group. In contrast, ERPs of all the three layers were prolonged in the hypertrophic heart, while the ERPs-dispersion was reduced significantly after mainlining of amiodarone. The ERPs-dispersion was significantly increased in the hypertrophic heart but not in the normal heart using "long-short" and "short-long" interval stimulation technique. It was concluded that (1) the differences in ERPs-dispersion among the three layers were significant in hypertrophic heart, and differences were not significant in normal canine heart; (2) ERPs of each three-myocardial layers were significantly prolonged after using amiodarone, but the ERPs-dispersion decreased in hypertrophic heart and (3) the programmed extrastimulus technique of "long-short" and "short-long" intervals increased the transmural ERPs-dispersion in the hypertrophic heart.
Journal of Huazhong University of Science and Technology 02/2006; 26(2):182-4. · 0.58 Impact Factor
[show abstract][hide abstract] ABSTRACT: To observe the effects of simvastatin on nuclear factor kappaB (NF-kappaB)-DNA binding activity and on the expression of monocyte chemoattractant protein-1 (MCP-1) in atherosclerotic plaque in rabbits and to explore the anti-atherosclerotic properties beyond its lipid-lowering effects. Thirty-six New Zealand male rabbits were randomly divided into low-cholesterol group (LC), high-cholesterol group (HC), high-cholesterol+simvastatin group (HC+S) and then were fed for 12 weeks. At the end of the experiment, standard enzymatic assays, electrophoretic mobility shiftassay (EMSA), immunohistochemical staining, and morphometry were performed to observe serum lipids, NF-kappaB-DNA binding activity, MCP-1 protein expression, intima thickness and plaque area of aorta respectively in all three groups. Our results showed that the serum lipids, NF-kappaB-DNA binding activity, expression of MCP-1 protein, intima thickness, and plaque area of aorta in the LC and HC+S groups were significantly lower than those in the HC group (P<0.05). There was no significant difference in the serum lipids between the LC and HC+S groups (P>0.05), but the NF-kappaB-DNA binding activity, the expression of MCP-1 protein and the intima thickness and plaque area of aorta in the HC+S group were significantly decreased as compared to the LC group (P<0.05). This study demonstrated that simvastatin could decrease atherosclerosis by inhibiting the NF-kappaB-DNA binding activity and by reducing the expression of MCP-1 protein.
Journal of Huazhong University of Science and Technology 01/2006; 26(2):194-8. · 0.58 Impact Factor
[show abstract][hide abstract] ABSTRACT: Benefits of cardiac resynchronization therapy (CRT) are well established. However, less is understood concerning its effects on myocardial repolarization and the potential proarrhythmic risk.
Healthy dogs (n = 8) were compared to a long QT interval (LQT) model (n = 8, induced by cesium chloride, CsCl) and a dilated cardiomyopathy with congestive heart failure (DCM-CHF, induced by rapid ventricular pacing, n = 5). Monophasic action potential (MAP) recordings were obtained from the subendocardium, midmyocardium, subepicardium, and the transmural dispersion of repolarization (TDR) was calculated. The QT interval and the interval from the peak to the end of the T wave (T(p-e)) were measured. All these characteristics were compared during left ventricular epicardial (LV-Epi), right ventricular endocardial (RV-Endo), and biventricular (Bi-V) pacing. In healthy dogs, TDR prolonged to 37.54 ms for Bi-V pacing and to 47.16 ms for LV-Epi pacing as compared to 26.75 ms for RV-Endo pacing (P < 0.001), which was parallel to an augmentation in T(p-e) interval (Bi-V pacing, 64.29 ms; LV-Epi pacing, 57.89 ms; RV-Endo pacing, 50.29 ms; P < 0.01). During CsCl exposure, Bi-V and LV-Epi pacing prolonged MAPD, TDR, and T(p-e) interval as compared to RV-Endo pacing. The midmyocardial MAPD (276.30 ms vs 257.35 ms, P < 0.0001) and TDR (33.80 ms vs 27.58 ms, P=0.002) were significantly longer in DCM-CHF dogs than those in healthy dogs. LV-Epi and Bi-V pacing further prolonged the MAPD and TDR in this model.
LV-Epi and Bi-V pacing result in prolongation of ventricular repolarization time, and increase of TDR accounted for a parallel augmentation of the T(p-e) interval, which provides evidence that T(p-e) interval accurately represents TDR. These effects are magnified in the LQT and DCM-CHF canine models in addition to their intrinsic transmural heterogeneity in the intact heart. This mechanism may contribute to the development of malignant ventricular arrhythmias, such as torsades de pointes (TdP) in congestive heart failure (CHF) patients treated with CRT.
Pacing and Clinical Electrophysiology 10/2005; 28(10):1098-106. · 1.75 Impact Factor
[show abstract][hide abstract] ABSTRACT: To evaluate the effects of W-7, a calmodulin inhibitor, on transmural dispersion of repolarization (TDR), early after depolarization (EAD) and torsade de pointes (TdP) induction after administration of d-sotalol in isolated rabbit heart.
TdP was induced by d-sotalol (30 micromol/L), bradycardia, and hypokalemic (1.5 mmol/L)/hypomagnesaemic (0.35 mmol/L) solution in isolated female rabbit hearts. Thirty six rabbit hearts were divided into 4 groups (n = 9 each): d-sotalol alone, d-sotalol + W-7 (20 micromol/L), d-sotalol + W-7 (50 micromol/L), and d-sotalol + W-7 (100 micromol/L). Monophasic action potentials (MAPs) of the left ventricular epimyocardium (Epi), midmyocardium (M), and endomyocardium (Endo) were recorded simultaneously with ECG. The incidence of EAD and TdP were observed as well.
Treatment with d-sotalol alone prolonged ventricular MAP duration and QT interval, increased TDR, and evoked high incidence of EAD (9/9) and spontaneous TdP (7/9) in hypokalemic/hypomagnesaemic solution in female rabbit heart. W-7 concentration-dependently decreased incidence of TdP (4/9 in 20 micromol/L; 2/9 in 50 micromol/L; 1/9 in 100 micromol/L). This effect of W-7 coincided with the decreased incidence of EAD (5/9 in 20 micromol/L; 4/9 in 50 micromol/L; 1/9 in 100 micromol/L). However, the d-sotalol-induced prolongation of QT interval and TDR was not significantly altered by W-7 at the three concentration used.
In isolated female rabbit hearts, calmodulin antagonist W-7 suppresses d-sotalol-induced TdP without altering TDR but does suppress EAD. The effects observed with W-7 also suggest a possible important role for calmodulin-activated enzymes in the induction of TdP.
Zhonghua xin xue guan bing za zhi [Chinese journal of cardiovascular diseases] 05/2005; 33(4):364-8.
[show abstract][hide abstract] ABSTRACT: Upregulation of hTERT mRNA plays an important role during the occurrence and development of laryngeal squamous cell carcinoma. Most hTERT mRNA in plasma from patients with laryngeal squamous cell carcinoma is derived from tumour cells; moreover, the determination of plasma hTERT mRNA contributes to tumour diagnosis and the observation of curative effect.
To establish a real-time fluorescent reverse transcriptase polymerase chain reaction (RT-PCR) and to quantitate the level of human telomerase reverse transcriptase (hTERT) mRNA in carcinoma tissue and plasma from patients with laryngeal squamous cell carcinoma. We also wished to evaluate the role that hTERT mRNA expression plays during the occurrence and development of laryngeal squamous cell carcinoma, to probe the correlation between the expression level and the clinical and pathological parameters and to investigate the value of the determination of plasma hTERT mRNA in tumour diagnosis and the observation of curative effect.
A real-time fluorescent RT-PCR and a Lightcycler PCR system were used to quantitate the expression level of hTERT mRNA.
The expression levels of hTERT mRNA (NhTERT) from laryngeal squamous cell carcinoma tissue and corresponding adjacent non-cancerous tissue were 62.6 +/- 21.7 and 3.5 +/- 1.9, respectively. NhTERT was significantly elevated in laryngeal squamous cell carcinoma tissue, rising to 17.9-fold on average, but there was no significant correlation between NhTERT and either tumour location, differentiation degree, T grade or N grade. For healthy examinees, NhTERT in plasma was 1.3 +/- 0.9, compared to 13.1 +/- 9.4 and 9.3 +/- 5.8 in patients with laryngeal squamous cell carcinoma examined before and 2 days after surgery, respectively. Compared to healthy examinees, NhTERT in plasma from patients with laryngeal squamous cell carcinoma was significantly elevated; moreover, 2 days after surgery, NhTERT in plasma had decreased significantly in these patients.
[show abstract][hide abstract] ABSTRACT: To assess the value of echocardiography for detection of the flow-dependent epicardial coronary vasodilation, the changes in internal diameter of the left anterior descending coronary arteries (LAD) induced by reactive hyperemia were studied by echocardiography in 12 health anesthetized open-chest dogs. Reactive hyperemia was induced by brief occlusion of the left anterior descending coronary artery for 30 s followed by rapid release. The two- dimensional images of the left anterior descending coronary artery before and after reactive hyperemia with and without intracoronary infusion of N(G)-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide synthase (NOS) were investigated. The internal diameter of LAD was measured and its percent change induced by reactive hyperemia was calculated. Our results showed that the internal diameter of LAD was 2.23 +/- 0.19 mm before intracoronary infusion of L-NAME (baseline). The internal diameter of LAD significantly increased to 2.52 +/- 0.24 mm (P < 0.01) after reactive hyperemia at baseline, and the percent change in internal diameter of LAD was (13.10 +/- 3.59)%. The internal diameter of LAD before and after reactive hyperemia under the condition of intracoronary infusion of L-NAME was not different from that before reactive hyperemia at baseline. The percent change in internal diameter of LAD was (1.07 +/- 2.97)%, and it was significantly lower than that at baseline (P < 0.001). We are led to conclude that the change in internal diameter of LAD responding to reactive hyperemia was detected sensitively by echocardiography, and this change was associated with endothelium-derived nitric oxide.
Journal of Huazhong University of Science and Technology 02/2005; 25(4):464-7. · 0.58 Impact Factor