Repair of concurrent skin and nerve defect at palm and carpal on ulnar side with free medial plantar flap / 中华整形外科杂志

<p><b>OBJECTIVE</b>To explore a new method for repair of concurrent skin and nerve defect at palm and carpal on ulnar side.</p><p><b>METHODS</b>From April 2000 to August 2009, five cases with concurrent skin and nerve defect at palm and carpal on ulnar side were reconstructed with free medial plantar flaps. Palmar nervous proprii defect at ulnar side of little finger was repaired by the first toe tibia nervous proprii in one case. The superficial branch of radial nerve was applied to repair the defect of ulnar nerve, as well as its deep or superficial branch in two cases. The superficial branch of radial nerve was also used to repair the defect of superficial branch of ulnar nerve, common palmar digital nerve of the fourth finger, Little finger ulnar palmar nervous proprii in one case. The dorsal branch of ulnar nerve was applied to repair the defect of superficial branch of ulnar nerve, common palmar digital nerve of the fourth finger, little finger ulnar palmar nervous proprii in one case. The vascular bundle of medial plantar flap was anastomosed with ulnar vascular bundle. The wounds at donor sites were covered with free skin grafts which were obtained from upper leg.</p><p><b>RESULTS</b>All the flaps and skin grafts were survived completely. The five patients were followed up for six months to four years with no muscular atrophy or claw hand deformity. The esthetic result was satisfied. The Sensory of flaps and fingers recovered to S3 to S3+. The two-point discrimination distance on flaps was range from 7 mm to 10 mm. The postoperative comprehensive evaluation was excellent in the cases whose superficial and deep branches of ulnar nerve were repaired.</p><p><b>CONCLUSIONS</b>Free medial plantar flap is an effective method to repair concurrent skin and nerve defect at palm and carpal on the ulnar side.</p>

Effects of docosahexaenoic acid on sodium channel current and transient outward potassium channel current in rat ventricular myocytes / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the effects of docosahexaenoic acid (DHA) on sodium channel current (I(Na)) and transient outward potassium channel current (I(to)) in rat ventricular myocytes and to evaluate potential anti-arrhythmic mechanisms of DHA.</p><p><b>METHODS</b>I(Na) and I(to) of individual ventricular myocytes were recorded by patch-clamp technique in whole-cell configuration at room temperature. Effects of DHA at various concentrations (0, 20, 40, 60, 80, 100 and 120 micromol/L) on I(Na) and I(to) were observed.</p><p><b>RESULTS</b>(1) I(Na) was blocked in a concentration-dependent manner by DHA, stably inactivated curves were shifted to the left, and recover time from inactivation was prolonged while stably activated curves were not affected by DHA. At -30 mV, I(Na) was blocked to (1.51 ± 1.32)%, (21.13 ± 4.62)%, (51.61 ± 5.73)%, (67.62 ± 6.52)%, (73.49 ± 7.59)% and (79.95 ± 7.62)% in the presence of above DHA concentrations (all P < 0.05, n = 20), and half-effect concentration (EC(50)) of DHA on I(Na) was (47.91 ± 1.57)micromol/L. (2) I(to) were also blocked in a concentration-dependent manner by DHA, stably inactivated curves were shifted to the left, and recover time from inactivation was prolonged with increasing concentrations of DHA, and stably activated curves were not affected by DHA. At +70 mV, I(to) was blocked to (2.61 ± 0.26)%, (21.79 ± 4.85)%, (63.11 ± 6.57)%, (75.52 ± 7.26)%, (81.82 ± 7.63)% and (84.33 ± 8.25)%, respectively, in the presence of above DHA concentrations (all P < 0.05, n = 20), and the EC(50) of DHA on I(to) was (49.11 ± 2.68)micromol/L.</p><p><b>CONCLUSION</b>The blocking effects of DHA on APD and I(to) may serve as one of the anti-arrhythmia mechanisms of DHA.</p>

Effects of valsartan on myocardial calcium/calmodulin-dependent protein kinase-II expression and activity in a rabbit model of heart failure / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the effects of valsartan on myocardial expression and activity of calcium/calmodulin-dependent protein kinase-II (CaMK II) in a rabbit model of heart failure.</p><p><b>METHODS</b>Rabbits were divided into sham-operated group, heart failure group (volume overload by aortic valve destruction induced aortic insufficiency plus pressure overload induced by abdominal aortic banding) and heart failure plus valsartan (20 mg x kg(-1) x d(-1), n = 9 each). Seven weeks later, echocardiography and hemodynamic examinations were performed and myocardial CaMK II expression and activity were detected by Western blot and CaMK II activity assay kit, respectively.</p><p><b>RESULTS</b>Compared with the sham operated rabbits, left ventricular mass index [LVMI (3.61 +/- 0.09) g/kg vs. (1.32 +/- 0.06) g/kg, P<0.05] and end-diastolic pressure [LVEDP (23.00 +/- 2.37) mm Hg (1 mm Hg = 0.133 kPa) vs. (-1.50 +/- 0.5) mm Hg, P<0.05] were significantly increased while left ventricular shortening fractions [LVFS (17.38 +/- 3.13)% vs. (37.83 +/- 3.58)%, P<0.05] and ejection fraction [LVEF (38.50 +/- 6.07)% vs. (71.92 +/- 4. 56)%, P<0.05] were significantly decreased (all P<0.05) in heart failure rabbits, these changes could be significantly attenuated by valsartan treatment: LVMI [(2.07 +/- 0.14) g/kg vs. (3.61 +/- 0.09) g/kg, P<0.05], LVEDP [(2.17 +/- 0.72) mm Hg vs. (23.00 +/- 2.37) mm Hg, P<0.05], LVFS [(33.83 +/- 2.85)% vs. (17.38 +/- 3.13)%, P<0.05] and LVEF [(64.45 +/- 3.66)% vs. (38.50 +/- 6.07)%, P<0.05]. CaMK II expression (1.45 +/- 0.13 vs 0.89 +/- 0.05, 1.13 +/- 0.12, P<0.05) and activity [(3.54 +/- 0.17) pmol x min(-1) x microg(-1) vs. (2.18 +/- 0.13) pmol x min(-1) x microg(-1), (2.79 +/- 0.14) pmol x min(-1) x microg(-1), P<0.05] in heart failure rabbits were significantly increased than those sham operated rabbits which could be significantly attenuated by valsartan treatment.</p><p><b>CONCLUSION</b>Valsartan improved cardiac function in heart failure rabbits probably via downregulating myocardial CaMK II expression and activity.</p>

Effects of docosahexaenoic acid on action potential and transient outward potassium current on ventricular myocytes of Sprague-Dawley rat / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the effects of docosahexaenoic acid (DHA) on action potential (AP) and transient outward potassium current (I(to)) on ventricular myocytes of Sprague-Dawley rat.</p><p><b>METHODS</b>Calcium-tolerant ventricular myocytes were isolated by enzyme digestion. The changes of AP and I(to) with increasing DHA at concentrations of 0, 10, 20, 40, 60, 80, 100, 120 and 200 micromol/L were recorded by whole-cell patch clamp configuration.</p><p><b>RESULTS</b>(1) Action potential durations (APDs) were not affected by DHA at concentrations from 0 micromol/L to 30 micromol/L, while APDs were gradually prolonged in proportion with increasing DHA concentrations from 30 micromol/L to 200 micromol/L within 5 minutes and remained stable thereafter. APD(25), APD(50) and APD(75) were (7.7 +/- 2.0) ms, (21.2 +/- 3.5) ms, and (100.1 +/- 9.8) ms respectively at 100 micromol/L DHA. APD(25), APD(50), and APD(75) were (15.2 +/- 4.0) ms, (45.7 +/- 6.8) ms, and (215.6 +/- 15.7) ms respectively at 200 micromol/L DHA. (2) I(to) was gradually reduced with the increasing DHA concentrations from 10 micromol/L to 200 micromol/L. I(to) was blocked by DHA in a dose-dependent manner. I(to) current density was (30.1 +/- 7.2) pA/pF at DHA concentration of 60 micromol/L and its half-inhibition concentration was 58.3 micromol/L.</p><p><b>CONCLUSION</b>APDs are gradually prolonged while I(to) reduced with increasing concentrations of DHA which might contribute to the anti-arrhythmia mechanisms of DHA.</p>

Defibrillation efficacy of a newly developed automated external defibrillator in a swine ventricular tachycardia/fibrillation model / 中华心血管病杂志

<p><b>OBJECTIVE</b>The aim of this study was to evaluate the recognition and defibrillation efficiency of a newly developed automated external defibrillator (AED).</p><p><b>METHOD</b>Ventricular tachycardia (VT)/ventricular fibrillation (VF) was induced by alternating current (50 Hz) through an electrode placed on apex of right ventricle in 23 anesthetized swine and recorded, recognized and defibrillated by a newly developed AED.</p><p><b>RESULTS</b>A total of 96 VF was induced and 145 defibrillations were recorded. We analyzed available 167 electrocardiosignal with a total length of 103,740 seconds. The accuracy, sensitivity and the specificity of the AED on VT/VF recognition are 99.5%, 98.2% and 99.6%, respectively. The success rate of defibrillation was 33.4% which increased in proportion to defibrillation energy. The defibrillation threshold of energy is 29.10-116.91 (78.75 +/- 35.64) J, the defibrillation threshold of electric quantity is (0.11 +/- 0.04) C and the defibrillation threshold of voltage is (1216.67 +/- 260.87) V.</p><p><b>CONCLUSIONS</b>This newly developed AED has high sensitivity and the specificity on recognizing VT/VF. The lower success rate of defibrillation of this AED is associated with the low defibrillation energy during defibrillation which needs to be improved on further development.</p>

The changes of funny currents in the ventricular myocytes of neonatal rats and adult rats / 中国应用生理学杂志

<p><b>AIM</b>To record funny currents (If) of ventricular myocytes and to analysize hyperpolarization-activated cation channel(HCN) expression in the rats of different ages.</p><p><b>METHODS</b>Fresh ventricular myocytes were isolated from 3 days rats and adult rats.HCN expressions were measured by real-time quantitative polymerase chain reaction(real-time PCR). It was recorded through whole-cell patch clamp.</p><p><b>RESULTS</b>HCN1, HCN2, HCN3, HCN4 mRNA represented 0.23% +/- 0.01%, 83.58% +/- 0.04%, 0.79% +/- 0.01%, 15.44% +/- 0.01% of total HCN mRNA in the neonatal rats, respectively. If was recorded and the threshold for activation was -75 mV. In the adult rat, HCN1, HCN2, HCN3, HCN4 mRNA represented 0.72% +/- 0.02%, 91.58% +/- 0.08%, 0.27% +/- 0.02%, 7.12% +/- 0.02% of total HCN mRNA. The ratio of HCN2 to HCN4 was approximately (13.06 +/- 0.21):1. The threshold for activation of If was approximately -115 mV in the adult rats.</p><p><b>CONCLUSION</b>With the development of rats, the value of If is smaller. The threshold for activation of If is more negative. The ratio of HCN2 to HCN4 is bigger.</p>

Effects of different amlodipine isomers on L-type calcium current of rat ventricular myocytes / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the effects of different amlodipine isomers on L-type calcium current (ICa-L) and kinetics of rat ventricular myocytes.</p><p><b>METHODS</b>Rat ventricular myocytes were isolated by enzyme digestion. ICa-L, peak currents, I-V curves, steady state activation curves, steady state inactivation curves and recovery curves from inactivation with S-amlodipine, R-amlodipine and R, S-amlodipine at concentrations of 0.1, 0.5, 1, 5, and 10 micromol/L were recorded by whole-cell patch clamp configuration.</p><p><b>RESULTS</b>At the concentrations of 0.1, 0.5, 1, 5, and 10 micromol/L, ICa-L were blocked in a dose-dependent manner by S-amlodipine [(1.5 +/- 0.2)%, (25.4 +/- 5.3)%, (65.2 +/- 7.3)%, (78.4 +/- 8.1)%, and (94.2 +/- 5.0)%] and by R, S-amlodipine [(0.9 +/- 0.1)%, (10.4 +/- 3.2)%, (69.1 +/- 5.3)%, (75.2 +/- 7.0)%, and (81.6 +/- 6.4)%]. I-V curves were significantly shifted upward, steady state activation and inactivation curves were significantly shifted to left by S-amlodipine and R, S-amlodipine (0.1 micromol/L to 10 micromol/L). Recovery time from inactivation was also significantly prolonged by S-amlodipine [(210.1 +/- 19.5) ms, (225.2 +/- 21.3) ms, (241.7 +/- 20.3) ms, (252.3 +/- 24.2) ms, and (282.6 +/- 23.2) ms] and by R, S-amlodipine [(208.7 +/- 17.4) ms, (215.8 +/- 18.3) ms, (225.2 +/- 21.3) ms, (235.8 +/- 22.7) ms, and (252.3 +/- 24.2) ms] in a dose-dependent manner. The observed effects of S-amlodipine were more potent than those of R, S-amlodipine (P < 0.05). However, all these parameters were not affected by R-amlodipine at various concentrations (P > 0.05).</p><p><b>CONCLUSION</b>L-type calcium current of rat ventricular myocytes could be blocked by R, S-amlodipine and S-amlodipine in a dose-dependent manner.</p>

Association between CYP2C9 and VKORC1 genetic polymorphism and warfarin dose requirements / 中华心血管病杂志

<p><b>OBJECTIVE</b>To assess the contribution of vitamin K epoxide reductase complex 1 (VKORC1) and cytochrome P450 2C9 (CYP2C9) genotype, age, body size, height, and weight to warfarin dose requirement.</p><p><b>METHODS</b>Blood samples were collected from 191 patients receiving warfarin therapy. Patients's age, gender, height, and weight were registered. PCR-RFLP method was used for the detection of VKORC1-1639G > A and CYP2C9 genotype.</p><p><b>RESULTS</b>VKORC1-1639G > A genotyping showed that 159 patients were homozygous AA, 31 were heterozygous GA, and 1 was homozygous GG genotype. CYP2C9 genotyping showed that 176 patients were *1/*1, 15 patients were heterozygous *1/*3. Patients with VKORC1-1639 (G > A) GG + GA genotype required a significantly higher warfarin dose than those with AA genotype [(3.36 +/- 0.97) mg/d vs. (1.75 +/- 0.56) mg/d, P < 0.01], and patients with CYP2C9*1/*1 genotype also required a higher warfarin dose than those with CYP2C9*1/*3 genotype [(2.06 +/- 0.83) mg/d vs. (1.55 +/- 1.32) mg/d, P < 0.05]. The multiple linear regression model for warfarin dose indicated age, weight and VKORC1 genotype could explain the inter-individual variation in dose requirement of 9.3%, 7.4%, 51.9% patients, respectively; age, weight, CYP2C9 and VKORC1 genotype together could explain the inter-individual variation in dose requirement of 64.1% patients.</p><p><b>CONCLUSION</b>This study showed that age, weight and VKORC1 and CYP2C9 polymorphism had significant influences on warfarin dose requirements and should be considered on dosing regimens modification to improve the safety of warfarin therapy.</p>

The Alterations of Transient Outward Potassium Currents in Ventricular Myocytes from Diabetic Rats / 中华高血压杂志

Objective To investigate the alterations and molecular mechanism of transient outward potassi- um currents(I_(to)) in ventricular myocytes from diabetic rats and explore the mechanism of predisposition of arrhyth- mias in diabetes.Methods The diabetes model was established by a single injection of streptozocin(STZ,65 mg/ kg,pH=4.5) I.P.in male Sprague-Dawley rats with weight 150-200 g.Ventricular myocytes were isolated by enzymatic perfusion.The currents were recorded with the whole-cell patch clamp technique,and gene expres- sions of channel-forming subunits (Kv4.2,Kv4.3 and Kv1.4) were semi-quantified by the technique of reverse transcriptase-polymerase chain reaction(RT-PCR).Results The I_(to) density (+70 mV) decreased significantly in diabetic rats compared with controls[control:(30.6?3.8)pA/pF(n=9) vs diabetes:(18.9?3.3)pA/pF(n= 29)(P

Effects of amiodarone on funny current I(f) channel gene expression in neonatal rat ventricular myocytes / 中华心血管病杂志

<p><b>OBJECTIVE</b>To analysis the effect of amiodarone on funny current (I(f)) and hyperpolarization-activated cation channel (HCN) gene expressions of the neonatal rat ventricular myocytes.</p><p><b>METHODS</b>Ventricular myocytes of 1 - 3 days-old rats were isolated and cultured. The cardiomyocytes were treated by amiodarone (0.01, 0.1, 1, 10, 100 micromol/L) for 3 hours or amiodaron (10 micromol/L) for 0, 0.5, 1, 3, 6 hours. The I(f) and HCN 1 - 4 gene expressions were measured through the whole-cell configuration of the patch-clamp technique and real-time quantitative polymerase chain reaction (real-time PCR) using SYBR Green PCR kit.</p><p><b>RESULTS</b>(1) HCN1, HCN2, HCN3 and HCN4 represented (0.23 +/- 0.01)%, (83.58 +/- 0.04)%, (0.79 +/- 0.01)% and (15.44 +/- 0.01)% of total HCN mRNA, respectively. (2) Amiodaron resulted in a dose-dependent I(f) [(3.1 +/- 0.9)%, (9.7 +/- 2.4)%, (36.7 +/- 5.8)%, (80.3 +/- 1.8)% and (85.9 +/- 3.1)%, respectively at -145 mV, IC(50) (1.32 +/- 0.28) micromol/L], HCN2 [(2.1 +/- 0.8)%, (8.9 +/- 3.6)%, (30.1 +/- 4.2)%, (78.3 +/- 3.6)% and (81.1 +/- 1.9)%, respectively] and HCN4 decrease [(0.5 +/- 0.2)%, (2.1 +/- 2.6)%, (8.8 +/- 3.2)%, (60.1 +/- 4.6)% and (59.6 +/- 6.5)%, respectively]. (3) Amiodaron (10 micromol/L) also induced a time-dependent I(f) [(1.1 +/- 0.1)%, (12.6 +/- 2.3)%, (80.6 +/- 2.2)% and (80.1 +/- 2.1)%, respectively], HCN2 [(1.0 +/- 0.1)%, (9.8 +/- 3.9)%, (82.9 +/- 4.6)% and (83.9 +/- 1.7)%, respectively] and HCN4 decrease [(0.1 +/- 0.1)%, (1.9 +/- 1.1)%, (59.4 +/- 7.8)% and (60.9 +/- 3.1)%, respectively]. However, HCN1 and HCN3 expressions were not affected by amiodaron treatment.</p><p><b>CONCLUSION</b>Current density of I(f) and the expression of HCN2 and HCN4 were decreased by amiodaron which might be the possible antiarrhythmic working mechanisms of amiodaron.</p>

Effects of metoprolol on cardiac function and myocyte calcium regulatory protein expressions in rabbits with experimental heart failure / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the effects of metoprolol on cardiac function and myocyte calcium regulatory protein expressions in rabbits with heart failure.</p><p><b>METHODS</b>Rabbit heart failure model was established by aortic insufficiency induced volume overload followed 14 days later by pressure overload induced by abdominal aorta constricting (HF, n = 11), another 8 rabbits with heart failure were treated with metoprolol (ME) for 6 weeks, sham-operated rabbits (n = 11) served as control. Cardiac function was measured by echocardiography at the end of study. Caffeine-induced calcium transients of myocytes loaded by Fluo-3/AM were observed under Laser scanning confocal microscope. Calcium regulatory protein expression was determined by Western blot analysis.</p><p><b>RESULTS</b>Compared to control animals, the ejection fractions [EF, (45.7 +/- 3.0)% vs. (72. 6 +/- 5.0)%, P < 0.01] and the amplitude of caffeine-induced calcium transients [(16.0 +/- 3.5) FI vs. (43.5 +/- 6.2) FI, P < 0.01] were significantly decreased while its time to peak was significantly prolonged [(129.8 +/- 14.5) s vs. (52.2 +/- 7.4) s, P < 0.01] in HF rabbits. The RyR2 (0.106 +/- 0.007 vs. 0.203 +/- 0.021, P < 0.01) and the ratio of SERCA2a and NCX (1.22 +/- 0.23 vs. 1.96 +/- 0.12, P < 0.01) were also significantly reduced in myocytes of HF rabbits. Metoprolol significantly attenuated the decrease of EF [(60.2 +/- 5.1)%], the amplitude of calcium transient [(32.8 +/- 5.4) FI], the RyR2 expression (0.164 +/- 0.016) and the ratio of SERCA2a and NCX (1.68 +/- 0.17, all P < 0.05 vs. HF rabbits) and attenuated the increase of the time to peak of caffeine-induced calcium transients [(91.4 +/- 10.9) s, P < 0.05 vs. HF rabbits].</p><p><b>CONCLUSION</b>Metoprolol could improve the cardiac function possibly by preventing the alterations of calcium regulatory proteins and increasing calcium transients in failing heart.</p>

Effects of simvastatin on the left ventricular expression of transient outward potassium channel in rabbits with experimental heart failure / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the effects of simvastatin on the left ventricular (LV) expression of transient outward potassium channel in rabbits with experimental heart failure (HF).</p><p><b>METHODS</b>HF model was established by ligating the left anterior descending coronary artery of rabbits. Rabbits were randomized into simvastatin group (HF + S, 10 mg x kg(-1) x d(-1) for 10 weeks, n = 8), HF group (n = 9), and sham group (n = 9). Left ventricular remodeling and function were evaluated by echocardiography and hemodynamic measurements 10 weeks after operation. The mRNA and protein expressions of K(v)1.4, K(v)4.2 and K(v)4.3 potassium channel alpha subunit in LV were determined by semi-quantitative RT-PCR and Western blot.</p><p><b>RESULTS</b>Simvastatin attenuated LV remodeling and improved cardiac function. The mRNA and protein expressions of K(v)1.4, K(v)4.2 and K(v)4.3 potassium channel alpha subunit in HF rabbits (0.48 +/- 0.09, 0.37 +/- 0.07, 0.42 +/- 0.11; 0.33 +/- 0.09, 0.22 +/- 0.07, 0.29 +/- 0.11) were significantly decreased compared with sham rabbits (0.85 +/- 0.08, 0.66 +/- 0.07, 0.67 +/- 0.08; 0.68 +/- 0.13, 0.53 +/- 0.15, 0.49 +/- 0.10, all P < 0.01), and these decreases could be attenuated by simvastatin (0.77 +/- 0.10, 0.50 +/- 0.10, 0.57 +/- 0.12; 0.58 +/- 0.10, 0.36 +/- 0.10, 0.43 +/- 0.12, all P < 0.01 vs. HF).</p><p><b>CONCLUSION</b>Simvastatin not only attenuated LV remodeling and improved LV function but also prevented the downregulation of LV transient outward potassium channel expressions in rabbits with experimental HF.</p>

Association between unique nucleotide polymorphism of 2350G→A in angiotensin converting enzyme and myocardial infarction in Han nationality / 中华急诊医学杂志

0.05).Conclusions SNP of 2350G→A in ACE gene is associated with MI,AA genotype is probably a genetic marker of MI in Han nationality.

Establishment of a HEK293 cell line stably expressing human HCN2 gene / 中国应用生理学杂志

<p><b>AIM</b>To create a model for studying ionic channels by means of the expressing human HCN2 and G418-resistant HEK293 cell lines established.</p><p><b>METHODS</b>pcDNA3-hHCN2 was transfected with Lipofectin2000 into HEK293 cell line. The transfected cells would be survived in the further culture medium containing G418 antibiotic as the hHCN2 gene could express a G418 resistant products. Whole-cell patch clamp investigated that hHCN2 gene was transfected into HEK293 cells.</p><p><b>RESULTS</b>The G418 resistant (600 ug/ml) HEK293 cell line was established successfully and whole-cell patch clamp recorded ionic currents of transfected hHCN2.</p><p><b>CONCLUSION</b>The G418 resistant HEK293 cell line was successfully established with transfection of plasmid pcDNA3-hHCN2 by Lipofectin, which might be useful for studying the relationship between the structure and function of cloned ionic channels.</p>

Abnormal abundances of calcium cycling regulatory proteins in rabbit myocytes with heart failure / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the abnormal abundances of calcium regulatory proteins in rabbit myocytes with failing hearts.</p><p><b>METHODS</b>Sixteen rabbits were divided into two groups: 8 rabbits with heart failure induced by volume plus pressure overload and 8 sham-operated animals. The hemodynamic parameters and cardiac structure and function were detected via catheterization and echocardiography respectively. L-type calcium channel (LTCC), Ryanodine receptor 2 (RyR2), Sarcoplasmic reticulum Ca(2+)-ATPase (SERCA2a), and Na(+)-Ca(2+) exchanger (NCX) protein abundances were determined by Western blot analysis.</p><p><b>RESULTS</b>The ratio of left ventricular mass to body weight, heart rate and left ventricular end diastolic pressure in heart failure rabbits were significantly increased compared with sham-operated rabbits (P < 0.01), but their left ventricular shorten fraction [(21.3 +/- 4.00)% vs. (36.5 +/- 1.36)%] and ejection fraction (0.45 +/- 0.07 vs. 0.70 +/- 0.02) were decreased (P < 0.01). In heart failure rabbits, the abundances of LTCC and RyR2 were significantly decreased (R(LTCC/actin): 0.287 +/- 0.029 vs. 0.624 +/- 0.009; R(RyR2/actin): 0.106 +/- 0.001 vs. 0.203 +/- 0.011; P < 0.01), whereas the expressions of SERCA2a and NCX were markedly increased (R(NCX/actin): 0.497 +/- 0.015 vs. 0.221 +/- 0.014; R(SERCA2a/actin): 0.611 +/- 0.036 vs. 0.433 +/- 0.008; P < 0.01).</p><p><b>CONCLUSIONS</b>Reductions of LTCC and RyR2 might contribute to risk factors of systolic dysfunction in failing hearts. In early stage of heart failure, upregulated SERCA2a and NCX protein levels may be helpful for maintaining cardiac performance.</p>

Pacemaker current gene expression of rat mesenchymal stem cells and identification of mesenchymal stem cells expressing human pacemaker current gene (hHCN2) / 中华心血管病杂志

<p><b>OBJECTIVE</b>To study pacemaker current gene expression of mesenchymal stem cells (MSCs) and the electrophysiological property of MSCs expressing human pacemaker current gene.</p><p><b>METHODS</b>Pacemaker current gene expression of MSCs were studied by real-time quantitative polymerase chain reaction (real-time PCR) and pcDNA3-hHCN2 was transfected with Lipofectin 2000 into MSCs. hHCN2 expression at mRNA and at protein levels in the transfected cells were identified by real-time PCR and Western blot, respectively. The ionic currents of cloned hHCN2 (IhHCN2) were recorded and the current characteristics were studied through the whole-cell patch clamp technique.</p><p><b>RESULTS</b>mHCN1, mHCN2, mHCN3, mHCN4 represent (0.08+/-0.01)%, (77.16+/-0.03)%, (0.24+/-0.01)%, (22.53+/-0.02)% of total HCN mRNA in MSCs as determined by real-time PCR. Transfected hHCN2 ionic currents were recorded by whole-cell patch clamp and current density-voltage curves were obtained. The threshold for activation of IhHCN2 was approximately -80 mV and this current could be blocked by Cs+ (4 mmol/L). hHCN2 expression in transfected MSCs was detected both at mRNA and protein levels.</p><p><b>CONCLUSIONS</b>1. mHCN2 and mHCN4 represent the major populations of total HCN mRNA in MSCs. 2. Plasmid pcDNA3-hHCN2 by Lipofectin could be successfully transfected into MSCs with IhHCN2 recorded by whole-cell patch clamp technique, this study provides a basis for future antiarrhythmic gene therapy.</p>

The acute electrophysiological effects of amiodarone on normal and hypertrophied rat myocytes / 中华心血管病杂志

<p><b>OBJECTIVE</b>The aim of the present study was to investigate the acute action of amiodarone (AM) on the inward currents I(Na), I(Ca-L) and outward currents I(k), I(k1), I(to) in hypertrophied and normal rat ventricular myocytes.</p><p><b>METHODS</b>The pressure overload hypertrophy rat model was established by partial ligation of ascending aorta for 4 weeks. Ventricular myocytes were exposed to 0.01, 0.1, 1, 10 and 50 micromol/L AM and whole cell patch clamp technique was used to study the acute effects of AM on the inward currents I(Na), I(Ca-L) and outward currents I(k), I(k1), I(to).</p><p><b>RESULTS</b>(1) Compared with the normal ventricular myocytes, the current density of I(k), I(ks), I(to) and I(k1) were all decreased in hypertrophied myocytes, but I(Na) and I(Ca-L) remained unchanged. (2) I(Ca-L) was blocked by 59.0% +/- 4.4% in normal myocytes but only blocked by 16.7% +/- 8.0% in hypertrophied myocytes after 50 micromol/L AM application; IC(50) of I(Na) were 9.2 micromol/L and 5.9 micromol/L in normal and in hypertrophied myocytes, respectively; I(to) was blocked by 55.9% +/- 5.5% in normal myocytes and 23.0% +/- 2.8% in hypertrophied myocytes after 50 micromol/L AM application. I(k1) was not affected by AM in both normal and hypertrophied myocytes; I(ks) was blocked by 21.6% +/- 5.6% in normal myocytes and 42.7% +/- 9.2% in hypertrophied myocytes after 10 micromol/L AM application.</p><p><b>CONCLUSION</b>Our results show that the sensitivity of hypertrophied myocytes to AM on I(Na), I(ks) were higher than that of normal myocytes, while the sensitivity on I(Ca-L), I(k1), I(to) were lower than that of normal myocytes favoring the use of AM on hypertrophied myocardium for antiarrhythmic therapy.</p>

Malignant hypertrophic cardiomyopathy caused by the Arg723Gly mutation in beta-myosin heavy chain gene in a Chinese pedigree / 中华心血管病杂志

<p><b>OBJECTIVE</b>Hypertrophic cardiomyopathy (HCM) is a genetically and phenotypically heterogeneous disease and an Arg723Gly mutation in beta-myosin heavy chain (beta-MHC) gene was found in 3 Spanish families with malignant HCM. We detected this gene mutation in 5 Chinese pedigrees with hypertensive cardiomyopathy.</p><p><b>METHODS</b>Five Chinese pedigrees with HCM and 80 age-matched normal control subjects were chosen for the study. The exons in the functional regions of the beta-MHC gene were amplified with PCR and the products were sequenced, genotype and phenotype analyzed.</p><p><b>RESULTS</b>Arg723Gly mutation was identified in exon 20 in one pedigree. In this pedigree, 13 out of 25 family members were diagnosed as HCM, 5 died of heart failure, all HCM patients in this pedigree had Arg723Gly mutation and 3 of them had NYHA III and 2 of them were diagnosed as HCM before the age of 20.</p><p><b>CONCLUSIONS</b>Arg723Gly mutation was also one of the main disease-causing genes in Chinese familial HCM. The mutation of Arg723Gly is a malignant phenotype as shown by early progressive heart failure development and poor prognosis in this pedigree with Arg723Gly mutation.</p>

Mutation of Arg723Gly in beta-myosin heavy chain gene in five Chinese families with hypertrophic cardiomyopathy / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Hypertrophic cardiomyopathy (HCM) is a form of cardiomyopathy with an autosomal dominant inherited disease, which is caused by mutations in at least one of the sarcomeric protein genes. Mutations in the beta-myosin heavy chain (beta-MHC) are the most common cause of HCM. This study was to reveal the disease-causing gene mutations in Chinese population with HCM, and to analyze the correlation between the genotype and phenotype.</p><p><b>METHODS</b>The exons 3 to 26 of MYH7 were amplified by PCR, and the PCR products were sequenced in five non-kin HCM patients. A 17-year-old patient was detected to be an Arg723Gly mutation carrier. Then his family was gene-screened, and the correlation between genotype and phenotype was analyzed.</p><p><b>RESULTS</b>The mutation of Arg723Gly in a Chinese family with HCM was detected for the first time. With a C-G transversion in nucleotide 13,619 of the MYH7 gene, located at the essential light chain interacting region in S1, the replacement of arginine by glycine took place at amino acid residue 723. A two-dimensional echocardiogram showed moderate asymmetrical septal hypertrophy with left atria enlargement. There was no obstruction in the left ventricular outflow tract. In his family, a total of 13 individuals were diagnosed HCM and 5 of them were dead of congestive heart failure at a mean age of 66-year-old. Eight living members were all detected to carry the mutation, in which 3 developed progressive heart failure. Moreover, the heart function of the people evidently deteriorates when their age are older than 50. The mutation and the disease show co-separated.</p><p><b>CONCLUSION</b>The Arg723Gly mutation is a malignant type. In Chinese the mutation has the similar characters to the former report but has low degree malignant.</p>