Population characteristics and impact on heart rate variability, heart rate and blood pressure of passive smoking / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the basic characteristics of passive smoking population, and the impact of passive smoking on heart rate variability, heart rate and blood pressure.</p><p><b>METHODS</b>Eighty-six passive smokers [mean age: (52.4 ± 7.6) years] were recruited from patients and their relatives who visited cardiovascular outpatient department and excluded structural heart disease between June 2010 and June 2012, 80 normal subjects who were not exposed to smoking served as controls. Questionnaire survey, 24 hours ambulatory electrocardiogram examination and blood pressure measurement were performed in all recruited subjects.</p><p><b>RESULTS</b>(1) Non-marriage rate [18.60% (16/86) vs. 3.75% (3/80), P < 0.01] was significantly higher while education level were significantly lower in passive smoking group than in control group. Passive smokers were more likely service industry workers [29.07% (25/86) vs. 15.00% (12/80), P < 0.05] and had longer daily working time [(7.56 ± 1.24) h vs. (6.02 ± 0.96) h, P < 0.01], and were less likely to be professional technology industry employers [20.93% (18/86) vs. 36.25% (29/80), P < 0.05] and managers [13.95% (12/86) vs. 38.75% (31/80), P < 0.01] compared to controls. The main place of passive smoking was workplace (67.44%, 58/86), entertainment venues (63.95%,55/86), restaurants (48.84%, 42/86). (2) Standard of the normal sinus RR intervals (SDNN), the normal consecutive sinus RR interval difference between the root-mean-square (rMSSD) and adjacent the difference between the RR interval>50 ms the number of share the percentage (PNN50) were significantly lower in passive smoking group than in the control group (all P < 0.05). Every 5 min average of the standard deviation of sinus RR cycle (SDNN index) and 24 h every 5 min sinus RR interval mean standard deviation (SDANN) were similar between the 2 groups (all P > 0.05). Ultra-low-frequency power (VLF), low frequency power (LF), high frequency power (HF) and LF/HF were significantly lower in passive smoking group than in the control group (all P < 0.01). (3) Heart rate and diastolic blood pressure were significantly higher in passive smoking group than in control group (all P < 0.05) while systolic blood pressure was similar between the 2 groups (P > 0.05).</p><p><b>CONCLUSIONS</b>Marriage status, education level, profession and daily working time are independent determinants for passive smoking. Passive smoking mainly occurred in the workplace, entertainment venues and restaurants. Passive smoking is linked with reduced heart rate variability, increased 24 h average heart rate and diastolic blood pressure.</p>

Types and risk factors of arrhythmia on young patients with acute coronary syndrome in Henan province / 中华心血管病杂志

<p><b>OBJECTIVE</b>The types and risk factors of arrhythmia were analyzed on acute coronary syndrome (ACS) patients under the age of 44 years who were hospitalized in Henan province between September 2009 to June 2012.</p><p><b>METHODS</b>Medical records of eligible patients were obtained from the information system of the First Affiliated Hospital of Zhengzhou University teleconsultation information center. Middle aged and elderly ACS patients who were hospitalized at the same period served as controls. Data on arrhythmia types, blood pressure, thyroid disease, respiratory sleep apnea syndrome, smoking history, history of alcohol consumption, eating habits, family history of early-onset arrhythmia, laboratory tests were analyzed.</p><p><b>RESULTS</b>(1) Arrhythmia was detected in 110 out of young ACS patients (55%), which was significantly lower than that in the elderly ACS patients (71.05%, P < 0.01). (2) The top three arrhythmias in young ACS patients were: sinus tachycardia (30.50%), the premature ventricular contractions (19.00%), atrial flutter/atrial fibrillation (16.50%). Incidence of sinus tachycardia, atrial flutter/atrial fibrillation were significantly higher while incidence of ventricular tachycardia, ventricular fibrillation, paroxysmal supraventricular tachycardia were significantly lower in young ACS patients than in middle-aged ACS patients (all P < 0.05). The incidence of sinus tachycardia was higher while incidence of ventricular premature accelerated ventricular spontaneous cardiac rhythm, ventricular tachycardia, ventricular fibrillation, non-paroxysmal supraventricular tachycardia, atrial flutter/atrial fibrillation, paroxysmal supraventricular tachycardia, sinus bradycardia, nodal escape, atrioventricular block were significantly lower in young ACS patients than in elderly ACS patients (all P < 0.05). (3) Body mass index, incidence of smoking, coronary three-vessel disease, drinking, eating salty foods, thyroid dysfunction, sleep apnea were significantly higher in youth ACS patients with arrhythmia than in young ACS patients without arrhythmia (all P < 0. 05). (4) Logistic regression analysis found that number of diseased coronary vessels (OR = 24.293), smoking (OR = 1.112) and alcohol consumption (OR = 1.039) were independent risk factor for developing arrhythmia in young ACS patients from Henan province.</p><p><b>CONCLUSIONS</b>The main types of arrhythmia are sinus tachycardia, premature ventricular contractions, atrial flutter/atrial fibrillation and the major risk factors related to the arrhythmia are number of diseased coronary vessels, smoking and alcohol consumption in young ACS patients from Henan province.</p>

Effect of the smoking cessation services in the out-patient department for patients with coronary heart disease / 中华心血管病杂志

<p><b>OBJECTIVE</b>To evaluate the effects and clinical prognosis of out-patient department-based smoking cessation services for coronary heart disease (CHD) patients.</p><p><b>METHODS</b>A total of 140 smoking patients diagnosed with coronary heart disease in our cardiovascular department were randomly divided into the intensive smoking cessation clinic follow-up group (intervention group, patients were informed on the importance and methods to quit smoking at the first visit and reminded for that at months interval for 6 months, n = 70) and the conventional treatment group (control group, n = 70). After 6 months, the smoking status, cardiovascular event rates, drug usage, out-patient medical costs and quality of life were compared between the two groups.</p><p><b>RESULTS</b>Age, gender, concomitant diseases, drug usage were similar between the two groups at baseline (all P > 0.05). After 6 months, smoking quit rate [34.2% (24/70) vs. 5.7% (4/70), P < 0.01], drug use rates: lipid-lowering drugs [95.3% (67/70) vs. 80.4% (56/70)], β blockers [82.4% (57/70) vs. 41.3% (28/70)], and ACEI/ARB [61.4% (43/70) vs. 34.4% (24/70)] were significantly higher in the intervention group than in the control group, while total cardiovascular event rates [21.4% (15/70) vs. 47.1% (33/70), P < 0.01] and out-patient medical costs (3789.3 RMB vs. 4984.2 RMB, P < 0.01) were significantly lower in the intervention group than in the control group. The quality of life scores derived from MYO health survey questionnaire was significantly higher in the intervention group than in the control group (P < 0.01). The top three reasons responsible for continuous smoking for all patients failed to quit smoking were: (1) others smoked more than me and still alive and healthy [90.3% (56/62)]; (2) smoking helped me to keep relaxed and reduce trouble in daily work and life [70.9% (44/62)]; (3) smoking was essential while chatting and drinking with friends [66.1% (41/62)]. The overall satisfactory rate to this smoking cessation program was 42.8% and the satisfactory rate was up to 50.0% by patients.</p><p><b>CONCLUSIONS</b>Intensive outpatient smoking cessation follow-up program can significantly improve the smoking cessation rates, the guideline drug use rate and the quality of life while reduce medical costs for coronary heart disease patients.</p>

Quality of life change and its influencing factors in patients with acute coronary syndrome after drug-eluting stent implantation / 中华心血管病杂志

<p><b>OBJECTIVE</b>To prospectively evaluate the change of quality of life in patients with acute coronary syndrome following percutaneous coronary intervention (PCI) with drug-eluting stents and explore the influencing factors of quality of life.</p><p><b>METHODS</b>There hundred and thirty four consecutive patients with acute coronary syndrome receiving drug-eluting stents implantation between September 2008 and December 2009 were enrolled. Of them, two hundred and ninety three patients completed 36-item short form health survey at baseline and 6 months after PCI procedure. Change of quality of life and influencing factors on quality of life were analyzed.</p><p><b>RESULTS</b>Compared with baseline, quality of life improved significantly after PCI in terms of both physical component summary and mental component summary [ (51.07 ± 20.39) scores vs. (61.69 ± 19.73) scores and (63.27 ± 20.00) scores vs. (68.81 ± 18.71) scores, respectively; all P < 0.01]. Multiple linear regression analysis showed that female, diabetes and ST-segment elevation myocardial infarction were independent predictors of physical component summary improvements post PCI (β values were -0.310, -3.880 and 1.302, respectively; P < 0.05 or P < 0.01). Previous PCI and diabetes were independent predictors of mental component summary improvements post PCI (β values were -1.483 and -2.790, respectively; all P < 0.01).</p><p><b>CONCLUSIONS</b>Quality of life of acute coronary syndrome patients is significantly improved at 6 months after drug-eluting stents implantation. The predictors of physical quality of life improvement are female, diabetes, and ST-segment elevation myocardial infarction. Predictors of mental quality of life improvement are previous PCI and diabetes.</p>

Novel mutations of cardiac troponin T in Chinese patients with hypertrophic cardiomyopathy / 中华心血管病杂志

<p><b>OBJECTIVE</b>To screen the cardiac troponin T (TNNT2) mutations in Chinese patients with hypertrophic cardiomyopathy (HCM) and to analyze the potential link between the genotype and the phenotype.</p><p><b>METHODS</b>Clinical features of 100 probands with HCM and some family members were evaluated, 200 unrelated normal subjects served as control. The exons and flanking introns of TNNT2 were amplified with PCR and direct sequencing was used to screen TNNT2 mutations/polymorphisms.</p><p><b>RESULTS</b>Two novel missense mutations were detected in 2 HCM patients: R92W and R286H. These 2 mutations were not found in 200 non-HCM controls. A five-basepair insertion/deletion polymorphism in intron 3 of TNNT2 was identified in this HCM cohort but was not related to the phenotype.</p><p><b>CONCLUSIONS</b>Two missense mutations, R92W and R286H, were found in 2/100 patients with HCM, TNNT 2 mutation is relatively low in Chinese patients with HCM.</p>

Relationship between polymorphism of interleukin-8 and silicosis susceptibility / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the relationship between the polymorphisms of interleukin-8 (IL-8) and the silicosis susceptibility.</p><p><b>METHODS</b>The case group consisted of 101 male patients with stage I silicosis diagnosed by the Pneumoconiosis Diagnosis Expert Panel according to the Chinese National Diagnosis Criteria of Pneumoconiosis (GBZ 70-2009). The control group consisted of 121 workers without silicosis exposed to same dusts. The cases and the controls had the same dust exposure history. The peripheral venous blood was drawn from each subject. DNA was extracted from leucocytes by the salting method. The polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) techniques and PCR were used to examine polymorphism of IL-8 (Met31Arg, 781C/T, -251A/T and RA+860).</p><p><b>RESULTS</b>There were no the differences of age, cumulative exposure time and smoking between the cases and the controls (P > 0.05). The frequencies of IL-8 (Met31Arg) GT genotypes in cases and controls were 12.87% and 2.48%, respectively, there was significant difference (P < 0.05). The frequencies of allele G in cases and controls were 6.44% and 2.07%, respectively, there was significant difference (P < 0.05). The frequencies of IL-8 (-251A/T) AA genotypes in cases and controls were 9.90% and 25.64%, respectively, there was significant difference (P < 0.05). The frequencies of IL-8 (781C/T) CC, CT, TT genotypes in cases and controls were 38.61%, 40.59%, 20.79% and 46.28%, 40.50%, 13.22%, respectively, there was no significant difference (P > 0.05). The frequencies of IL-8 (RA+860) GG, GC and CC genotypes in cases and controls were 75.25%, 21.78%, 2.97%, 80.17%, 14.88%, 4.96%, respectively, there was no significant difference (P > 0.05).</p><p><b>CONCLUSIONS</b>IL-8 (Met31Arg and -251A/T) genetic polymorphisms might play a role in the development of silicosis. The risk of pneumoconiosis in workers carrying (Met31Arg) genotype GT is likely to increase. The risk of pneumoconiosis in workers carrying IL-8 (-251A/T) AA genotype is likely to decrease. The relationship between IL-8 781C/T and RA+860 genes polymorphisms and silicosis is not found.</p>

Relationship between gene polymorphism of fibronectin and pneumoconiosis / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the relationship between the genetic polymorphism of fibronectin (FN) (4 genetic locus) and pneumoconiosis.</p><p><b>METHODS</b>128 male I-period pneumoconiosis were selected as cases who were examined with radiography and diagnosed by the Pneumoconiosis Diagnosis Expert Panel, based on the Chinese National Diagnosis Criteria of Pneumoconiosis (GBZ 70 - 2002). According to 1:1 paired matching method, 128 dust exposure workers were selected as control who were exposed to same dust as cases. The difference of age and cumulative length of service between case and control was not over five years and two years, respectively. 5 ml peripheral venous blood was drawn and anticoagulated with 2% EDTA. The polymorphisms of FN (MspI, TaqIb, HindIII, HaeIIIb) were detected, using the method of polymerase chain restriction fragment length polymorphism (PCR-RFLP) techniques and PCR.</p><p><b>RESULTS</b>The frequencies of FN Msp I (CC) in cases and control groups were 10.9% and 3.9%, respectively. The difference was significant (P < 0.05). The frequencies of FN (MspI) C allele were 41.8% and 31.2% in case and control, and the difference between cases and controls was significant (P < 0.05). The frequencies of FN HaeIIIb (AA) genotype in cases (24.2%) was higher than that in control groups (17.9%), OR = 5.0 (95% CI: 4.840 approximately 24.210). The frequencies of FN (HaeIIIb) A allele were 51.9% and 42.2% in case and control, and the difference was significant (P < 0.05). The difference of TaqIb and HindIII genotype between cases and controls were not significant (P > 0.05).</p><p><b>CONCLUSION</b>The risk of suffering from pneumoconiosis increases in workers carrying FN (MspICC or HaeIIIb AA) genotype after exposure to dust. Workers both carrying FN (HaeIIIb AA) and (MspICC) genotypes are more susceptible to pneumoconiosis. The relationship between genetic polymorphism of FN (TaqIIb, HindIII) and pneumoconiosis has not been found.</p>

Novel MYBPC3 mutations in Chinese patients with hypertrophic cardiomyopathy / 中华心血管病杂志

<p><b>OBJECTIVE</b>To screen the MYBPC3 gene mutations in Han Chinese patients with hypertrophic cardiomyopathy (HCM).</p><p><b>METHODS</b>Sixty-six patients with HCM were enrolled for the study. The exons in the functional regions of MYBPC3 were amplified with PCR and the products were sequenced.</p><p><b>RESULTS</b>Four novel mutations and four common polymorphisms were identified in this patient cohort. A Lys301fs mutation in exon10 was evidenced in a H30, and when he was 47 years old, he had the chest tightness, shortness of breath with septal hypertrophy of 18.7mm; a Asp463stop mutation in exon17 was detected in a H48, he was 24 years old 24-year-old when a medical examination showed ventricular septal hypertrophy of 15.4 mm; both Gly523Arg mutation in exon18 and Tyr847His mutation in exon26 were found in a H53 with onset age 36 years old, feeling chest tightness after excise and his ventricular septal hypertrophy was 27 mm that time. MYBPC3 mutations occurred in 4.5% patients in this cohort. These mutations were not found in 100 non-HCM control patients.</p><p><b>CONCLUSION</b>MYBPC3 mutation is presented in a small portion of Han Chinese patients with HCM.</p>

Relationship between genetic polymorphism of interleukin-6 and pneumoconiosis / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the relationship between interleukin-6 (IL-6) (-634C/G) genetic polymorphisms and the pneumoconiosis.</p><p><b>METHODS</b>A total of 104 male stage I pneumoconiosis patients diagnosed by the Pneumoconiosis Diagnosis Expert Panel according to the Chinese National Diagnosis Criteria of Pneumoconiosis (GBZ 70 - 2002) were selected. The pneumoconiosis comprised 66 silicosis and 38 coal worker' pneumoconiosis (CWP). A total of 122 workers exposed to same dusts as the patients but without pneumoconiosis including 77 exposed to silica dusts and 45 to coal dusts were selected. The patients and the controls had the same dust exposure history. The peripheral venous blood was drawn from each subject. The IL-6 (-634C/G) genetic polymorphisms were detected by polymerase chain reaction restriction fragment length polymorphisms (PCR-RFLP) techniques.</p><p><b>RESULTS</b>The frequencies of IL-6 (-634C/G) (CC, CG and GG) genotypes were 66.7%, 19.7% and 13.6% in silicosis group, 42.9%, 42.9% and 14.2% in silica dust exposure group, 73.7%, 18.4% and 7.9% in CWP group, 51.1%, 35.6% and 13.3% in coal dust exposure group respectively. The statistical analysis indicated that there was significant difference in the frequencies of IL-6 (-634C/G) (CC, CG and GG) genotypes between silicosis patients and workers exposed to silica dusts (P < 0.05).</p><p><b>CONCLUSION</b>IL-6 (-634 C/G) genetic polymorphisms might play a role in the occurrence of silicosis.</p>

Analysis of MYH7, MYBPC3 and TNNT2 gene mutations in 10 Chinese pedigrees with familial hypertrophic cardiomyopathy and the correlation between genotype and phenotype / 中华心血管病杂志

<p><b>OBJECTIVE</b>The aim of this study was to screen the disease-causing gene mutations and investigate the genotype-phenotype correlation in 10 Chinese pedigrees with familial hypertrophic cardiomyopathy (HCM).</p><p><b>METHODS</b>There are 91 family members from these 10 pedigrees and 5 members were normal mutated carriers, 23 members were HCM patients (14 male) aged from 1.5 to 73 years old. The functional regions of myosin heavy chain gene (MYH7), cardiac myosin-binding protein C (MYBPC3) and cardiac troponin T gene (TNNT2) were screened with PCR and direct sequencing technique. Clinical information from all patients was also evaluated in regard to the genotype.</p><p><b>RESULTS</b>Mutations were found in 5 out of 10 pedigrees. Mutations in MYH7 (Arg663His, Glu924Lys and Ile736Thr) were found in 3 pedigrees and 3 patients from these pedigrees suffered sudden death at age 20-48 years old during sport. Mutations in MYBPC3 were found in 2 pedigrees, 1 with complex mutation (Arg502Trp and splicing mutation IVS27 + 12C > T) and 1 with novel frame shift mutation (Gly347fs) and the latter pedigree has sudden death history. No mutation was identified in TNNT2.</p><p><b>CONCLUSIONS</b>Although the Han Chinese is a relatively homogeneous ethnic group, different HCM gene mutations were responsible for familiar HCM suggesting the heterogeneity nature of the disease-causing genes and HCM MYH7 mutations are associated with a higher risk of sudden death in this cohort. Furthermore, identical mutation might result in different phenotypes suggesting that multiple factors might be involved in the pathogenesis of familiar HCM.</p>

Novel SCN5A gene mutations associated with Brugada syndrome: V95I, A1649V and delF1617 / 中华心血管病杂志

<p><b>OBJECTIVE</b>Brugada syndrome is an inherited channelopathy that characterized by ST-segment elevation in the right precordial lead (V(1)-V(3)) on the electrocardiogram with or without right bundle branch block and related with high risk of sudden cardiac death and structurally normal hearts. The first and only gene linked to this disease is SCN5A, a gene encodes for alpha subunit of the cardiac sodium channel. The objective of this study is to explore SCN5A gene mutations in Chinese patients with Brugada syndrome.</p><p><b>METHODS</b>Four patients diagnosed as Brugada syndrome and nine patients with suspected Brugada syndrome were chosen for the study. The exons in the functional regions of SCN5A gene were amplified with polymerase chain reaction and the amplified products were sequenced with Sanger method. If a mutation was identified, patient's family members were also screened.</p><p><b>RESULTS</b>Two heterozygous mutations were found in one family diagnosed as Brugada syndrome. One missense mutation was a G-->A transition in the first nucleotide of codon 95 in SCN5A gene exon 3, which was predicted to result in substitution of Valine with Isoleucine (V95I). The other missense mutation was a C-->T transition in the second nucleotide of codon 1649 in SCN5A gene exon 28, which was predicted to result in substitution of Alanine with Valine (A1649V). A heterozygous mutation was identified in one family suspected to have the disease. The mutation was a three nucleotides (TCT) deletion that caused Phenylalanine deletion in codon 1617 in SCN5A gene exon 28. The three mutations were not detected in 100 control chromosomes.</p><p><b>CONCLUSIONS</b>Mutation in SCN5A gene is one of the causes of Brugada syndrome in Chinese. Three novel SCN5A gene mutations were identified in Chinese with Brugada syndrome, which expands the spectrum of SCN5A mutations associated with the disease.</p>

Heterozygous mutation in KCNQ1 cause Jervell and Lange-Nielsen syndrome / 中华心血管病杂志

<p><b>OBJECTIVE</b>Jervell and Lange-Nielsen syndrome (JLNS) is a severe cardioauditory syndrome manifested as QT interval prolongation, abnormal T waves, and relative bradycardia ventricular tachyarrhythmias. In this report, we screened a nonconsanguineous families with JLNS for mutations in KCNQ1.</p><p><b>METHODS</b>Mutation analysis was performed by using purified PCR products to direct sequence analysis on an ABI-3730XL automated DNA sequencer. The whole sequence of proband' KCNQ1 was screened firstly, then screened the mutation exon sequences of others of the family and 50 unrelated normal persons.</p><p><b>RESULTS</b>A heterogeneous mutation was identified in the patients of the JLNS family, a missense mutation (G-->T) at nucleotide 917 encoded in exon 6 of KCNQ1. This substitution leads to a change from glycine to Valine at codon 306(G306V) corresponding to the S5 transmembrane segment of KCNQ1. The other normal members of the family and 50 unrelated normal persons were not identified this mutation.</p><p><b>CONCLUSION</b>The result suggested that not only homozygous mutations or compound heterozygous mutations in KCNQ1 could cause Jervell-Lange-Nielsen syndrome, the single heterozygous mutation may also cause Jervell-Lange-Nielsen syndrome.</p>

Relationship between pneumoconiosis and the polymorphisms of HLA-DRB1*, DQB1* genes / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the relationship between the polymorphism of HLA-DRB1*, DQB* genes and the susceptibility of pneumoconiosis.</p><p><b>METHODS</b>1:1 case-control study was adopted. one hundred and thirteen cases of I grade pneumoconiosis were investigated. The control group were workers exposed to dust, who were the same sex, nationality, work place, time of beginning exposure and the cumulative exposure ages not over 2 years. PCR-SSP was used to detect 9 alleles in HLA-DRB1*, DQB1*. Information on related factors of pneumoconiosis was collected using a questionnaire. Univariate and multivariate logistic regression analysis were carried out with 1:1 case-control methodology.</p><p><b>RESULTS</b>The frequency of HLA-DRB1*08 allele in case group was significantly higher than that of the controls (OR: 6.000; 95% CI: 1.9060 - 18.9414). The frequencies of HLA-DRB1*09, HLA-DQB1*06 in case group were significantly lower than those of the controls (OR: 0.259, 0.300; 95% CI: 0.1436 - 0.6268, 0.1149 - 0.5837 respectively). There were significant relationship between HLA-DRB1*08, HLA-DRB1*09, HLA-DQB1*06 alleles and pneumoconiosis after adjusting age, smoking, beginning age of exposure and cumulative length of exposure with multivariate logistic regression analysis (OR: 7.804, 0.225, and 0.269; 95% CI: 2.077 - 29.307, 0.083 - 0.609 and 0.117 - 0.613 respectively. Survival analysis showed that HLA-DQB1*06 allele was a protective factor and HLA-DRB1*08 allele was a risk factor for affecting pneumoconiosis latent period.</p><p><b>CONCLUSION</b>HLA-DRB1*08 allele may be the susceptible risk gene for pneumoconiosis. HLA-DQB1*06 may be the protective gene against developing pneumoconiosis.</p>

Effects of quinidine on pinacidil-induced transmural dispersion of repolarization in canine right ventricular wall / 中华心血管病杂志

<p><b>OBJECTIVE</b>On the basis that pinacidil can produce an "all or none" repolarization in right ventricular wall of canine, to observe the effects of quinidine on the marked transmural dispersion of repolarization. Recent studies have shown that ventricular myocardium is composed of at least 3 electrophysiological distinct cell types: epicardial, endocardial, and midcardial cells. Differences in the response of the 3 cell types to pharmacologic agents and/or pathophysiological states often result in amplification of intrinsic electrical heterogeneities, thus providing a substrate as well as a trigger for the development of arrhythmias. The study was designed to observe the right ventricular transmural heterogeneity in vitro canine heart tissue preparation level.</p><p><b>METHODS</b>The strips were isolated from the anterior wall of the right ventricular of canine. The preparations perfused with oxygenated (95%O(2)/5%CO(2)) Tyrode's solution. The tissues were stimulated at basic cycle lengths of 1000 ms. Standard microelectrode techniques were used. Transmembrane action potentials were recorded from epicardial, midcardial and endocardial cells respectively from right ventricular free wall of canine on different conditions [perusing with Tyrode's solution (Control), pinacidil (2.5 micromol/L), and quinidine (5 micromol/L) in turn].</p><p><b>RESULTS</b>Compared with that of endocardial cells, the action potentials of canine ventricular epicardial and midcardial cells had more obvious spike and dome morphology. Pinacidil (2.5 micromol/L) caused a loss of the dome of transmembrane action potentials and a marked abbreviation of the action potential duration (APD) in right ventricular epicardial and midcardial cells, especially in epicardial cells, but not in endocardial cells (n = 10). With pinacidil (2.5 micromol/L), in epicardial cells, phase 2 amplitude of action potentials decreased from (117.7 +/- 9.3) mV to (71.3 +/- 6.4) mV (P < 0.01), and 90% of the APD(90) decreased from (198.2 +/- 20.8) ms to (103.9 +/- 13.5) ms (P < 0.01). The transmural dispersion of action potential duration increased from (48.5 +/- 9.2) ms to (128.7 +/- 13.5) ms (P < 0.01). Quinidine (5 micromol/L) effectively prolonged the APD abbreviated by pinacidil, restored or partly restored the dome of transmembrane action potentials of epicardial and midcardial cells but not of endocardial cells (n = 10). In epicardial cells phase 2 amplitude increased from (71.3 +/- 6.4) mV to (106.6 +/- 7.7) mV (P < 0.01), and 90% of the APD(90) increased from (103.9 +/- 13.5) ms to (185.9 +/- 15.7) ms (P < 0.01). The transmural dispersion of action potential duration significantly decreased from (128.7 +/- 13.5) ms to (54.3 +/- 10.8) ms (P < 0.01). Quinidine reduced pinacidil-induced transmural dispersion of phase 2 amplitude and the APD in right ventricular wall of canine.</p><p><b>CONCLUSION</b>By restoring the dome and the APD of the epicardial and midcardial cells action potentials, quinidine (5 micromol/L) could reduce the marked transmural dispersion of repolarization caused by pinacidil.</p>

Electrical heterogeneity of canine right ventricular transient outward potassium currents / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Some studies have confirmed that the right ventricular walls of most rodents, such as canines and humans, have evident transient outward potassium current (Ito1) heterogeneity, and this heterogeneity is closely related to J point elevation, J wave formation, and some ventricular tachycardias such as ventricular fibrillations caused by Brugada syndrome. This study is designed to investigate transmural electrical heterogeneity of the canine right ventricle during repolarization (phase 1) from the viewpoint of 4-aminopyridine sensitive and calcium-independent Ito1.</p><p><b>METHODS</b>Adult canine single right ventricular epicardial (Epi) cells, mid-myocardial (M) cells, and endocardial (Endo) cells were enzymatically dissociated. Whole cell voltage-clamp recordings were made to compare the Ito1 values of the three cell types.</p><p><b>RESULTS</b>At 37 degrees C and using 0.2 Hz and +70 mV depolarizing test potentials, the average peak Ito1 values of Epi cells and M cells averaged (4070 +/- 1720) pA and (3540 +/- 1840) pA, respectively. The activated and inactivated Epi and M cells kinetic processes were in accordance with the Boltzmann distribution. Compared with Ito1 in Epi cells and M cells, the average peak Ito1 in Endo cells was very low, averaged (470 +/- 130) pA.</p><p><b>CONCLUSIONS</b>These results suggest that there are evident differences and potent gradients in Ito1 between the three cardiac cell types, especially between Epi and Endo cells. These differences are among the prominent manifestations of right ventricular electrical heterogeneity, and may form an important ionic basis and prerequisite for some malignant arrhythmias in the right ventricle, including those arising from Brugada syndrome and other diseases.</p>

The mutation scanning of KCNQ1 gene for 31 long QT syndrome families / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To search for the mutations of potassium voltage-gated channel, KQT-like subfamily member 1(KCNQ1) gene in 31 Chinese long QT syndrome(LQTS) families.</p><p><b>METHODS</b>Due to the genetic heterogeneity, the genotype of patients was first predicted based on the spectrum of ST-T-wave patterns on ECG. Ten of 31 probands were considered as LQT1. Then the mutation of KCNQ1 gene was screened by the polymerase chain reaction and single strand conformation polymorphism (PCR-SSCP) technique combined with DNA sequencing in all members of these 10 families. To avoid omitting some LQT1 patients without typical characteristics and also to do methodological comparison, the mutations of KCNQ1 gene on 16 exons were screened by PCR and direct DNA sequencing in the rest 21 non-LQT1 probands only. Co-segregation analysis was carried out after the finding of an abnormal sequence. In case that the abnormality existed in patients only, the test of such exon was performed in 50 irrelevant normal individuals.</p><p><b>RESULTS</b>Two missense mutations and three single nucleotide polymorphisms (SNPs) were found in the LQT1 predicted families. The two mutations were S277L (1 family) and G306V (1 family) in exon 5 and were not reported previously. Three polymorphisms were 435C-->T (7 families), 1632C-->A (1 family), and IVS1+9 C-->G (3 families). Only a splice mutation IVS1+5G-->A (2 families) and a polymorphism IVS10+18C-->T (1 family) were found in the non-LQT1 predicted probands. All three mutations were localized within the functional domain of KCNQ1 and were co-segregated with the disease, and were not found in 50 normal individuals.</p><p><b>CONCLUSION</b>Two novel missense mutations, 1 splice mutation and four SNPs on KCNQ1 gene were found in the 31 LQTS families. Combined with ECG-based genotype prediction, PCR-SSCP could find most mutations on KCNQ1 and be a simple and economic method for screening LQTS.</p>

Clinical study of terminating biochemical pregnancy and early clinical pregnancy with mifepristone and misoprostol / 中华妇产科杂志

Objective To explore the efficacy and safety of terminating biochemical pregnancy (the stage in which intrauterine or ectopic pregnancy cannot be confirmed) with mifepristone and misoprostol. Methods Mifepristone (150 mg) combined with misoprostol (600 ?g) 3 days later were given to 500 biochemical pregnancies (G_1),500 early clinical pregnancies (G_2) and 500 clinical pregnancies (G_3) which were classified according to amenorrhea days,serum human chorionic gonadotropin-beta subunit (?- hCG) and vaginal B-ultrasonic examinations.All were observed for 6 hours after taking misoprostol and returned for assessment per week.Results Expulsion of conceptus was G_1 123 (24.6%,123/500),G_2 438 (87.6%,438/500) and G_3 467 (93.4%,467/500).Failure rate was G_1 6 (1.2%,6/500),G_2 24 (4.8%,24/500) and G_3 79 (15.8%,79/500) for ongoing pregnancies,hospitalizations for suspected ectopic pregnancies and surgical intervention for heavy or long-time bleeding.Bleeding cases during the administration of mifepristone were G_1 272 (54.4%,272/500),G_2 141 (28.2%,141/500) and G_3 87 (17.4%,87/500);the mean bleeding days were G_1 (5.8?1.5),G_2 (9.0?2.9) and G_3 (14.3?5.9) days.Other side effects including abdominal pain,nausea,vomiting and diarrhea were low and light in each group,increasing with advancing gestational age.Menses recovery was 486 (97.2%,486/500),452 (90.4%,452/500) and 433 (86.6%,433/500) for each group on scheduled time.Satisfaction was 499 (99.8%,499/500),485 (97.0%,485/500) and 369 (73.8%,369/500) respectively.Conclusion Mifepristone and misoprostol in combination is as safe,and effective for termination of biochemical pregnancies as ordinary medical abortion.It does not need to wait till ectopie pregnancy is excluded.