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551.
OBJECTIVES: We sought to characterize an animal model of the Wolff-Parkinson-White (WPW) syndrome to help elucidate the mechanisms of accessory pathway formation. BACKGROUND: Patients with mutations in PRKAG2 manifest cardiac hypertrophy and ventricular pre-excitation; however, the mechanisms underlying the development and conduction of accessory pathways remain unknown. METHODS: We created transgenic mice overexpressing either the Asn488Ile mutant (TG(N488I)) or wild-type (TG(WT)) human PRKAG2 complementary deoxyribonucleic acid under a cardiac-specific promoter. Both groups of transgenic mice underwent intracardiac electrophysiologic, electrocardiographic (ECG), and histologic analyses. RESULTS: On the ECG, approximately 50% of TG(N488I) mice displayed sinus bradycardia and features suggestive of pre-excitation, not seen in TG(WT) mice. The electrophysiologic studies revealed a distinct atrioventricular (AV) connection apart from the AV node, using programmed stimulation. In TG(N488I) mice with pre-excitation, procainamide blocked bypass tract conduction, whereas adenosine infusion caused AV block in TG(WT) mice but not TG(N488I) mice with pre-excitation. Serial ECGs in 16 mice pups revealed no differences at birth. After one week, two of eight TG(N488I) pups had ECG features of pre-excitation, increasing to seven of eight pups by week 4. By nine weeks, one TG(N488I) mouse with WPW syndrome lost this phenotype, whereas TG(WT) pups never developed pre-excitation. Histologic investigation revealed postnatal development of myocardial connections through the annulus fibrosum of the AV valves in young TG(N488I) but not TG(WT) mice. CONCLUSIONS: Transgenic mice overexpressing the Asn488Ile PRKAG2 mutation recapitulate an electrophysiologic phenotype similar to humans with this mutation. This includes procainamide-sensitive, adenosine-resistant accessory pathways induced in postnatal life that may rarely disappear later in life.  相似文献   
552.
Introduction: Myotonic dystrophy is caused by expansion of a CTG trinucleotide repeat on human chromosome 19, and leads to progressive skeletal myopathy and atrioventricular conduction disturbances. A murine model of myotonic dystrophy has been designed by targeted disruption of the myotonic dystrophy protein kinase (DMPK) gene. The DMPK-deficient mice display abnormalities in A-V conduction characteristics, similar to the human cardiac phenotype. The purpose of this study was to determine whether age-related progression of A-V block occurs in a mouse model of DMPK-deficiency.Methods and Results: Surface ECGs and intracardiac electrophysiology (EP) studies were performed in 60 immature and 90 adult homozygous (DMPK), heterozygous (DMPK), and wild-type (WT) DMPK control mice. Complete studies were obtained on 141 of 150 mice. The RR, PR, QRS, and QT intervals were measured on ECG. Sinus node recovery time, AV refractory periods, paced AV Wenckebach and 2:1 block cycle lengths, atrial and ventricular effective refractory periods were compared between genotypes and age groups. There were no differences in ECG intervals or EP findings in the young mutant mice, but progressive PR prolongation in older mice. The A-V conduction defects are also sensitive to DMPK gene dosage. Adult DMPK mice develop 1°, 2° and 3° A-V block, whereas DMPK mice develop only 1° heart block.Conclusion: These data demonstrate that both age and DMPK dose are important factors regulating cardiac conduction in myotonic dystrophy. This mouse model of DM is remarkably similar to the human phenotype, with age-related progression in atrioventricular conduction defects.  相似文献   
553.
高原红细胞增多症患者血清促红细胞生成素活性的观察   总被引:2,自引:0,他引:2  
目的 :探讨血清促红细胞生成素 (EPO)活性与西藏高原红细胞增多症 (HAPC)的关系。方法 :择藏汉两族男性 HAPC患者 (红细胞压积 >6 5 % ,血红蛋白 >2 0 0 g/ L) ,用骨髓造血细胞培养、细胞集落计数等方法测定其单位浓度血清 EPO的促骨髓造血干细胞增生活性 ,并与同族对照组进行统计学比较。结果 :1藏族 HAPC的 EPO检出率为 35 .7% ,汉族为 34 .6 % ,两组的发生率没有明显区别。2藏、汉两族 HAPC患者血浆 EPO水平的平均值较同族对照组分别增高了 148%和 2 84% ,藏族的增高差异有显著性意义。 3藏、汉两族 HAPC患者单位浓度的血清 EPO(1.0 5 IU/ L)活性均低于同族对照组 ,其中对红系集落形成单位 CFU- E的影响汉族降低了6 2 .4% ,藏族降低了 5 0 .7%。对红系爆式集落形成单位 BFU- E的影响汉族降低了 6 1.4% ,藏族降低了 2 7.3%。结论 :1藏、汉两族 HAPC组具有较高平均血浆 EPO水平 ;2藏、汉两族 HAPC组血清 EPO平均活性降低  相似文献   
554.
目的:探讨青年男性急性心肌梗死(AMI)患者的临床病变特点。方法:回顾性分析1578例不同年龄和不同性别AMI患者临床特征及冠状动脉造影结果。结果:≤40岁男性AMI患者88例。主诉多为胸痛,AMI梗死范围以前壁多见。与老年男性比较,危险因素以超重和吸烟为著。冠状动脉正常者较多,以单支病变为主,合并左主干病变较少。经皮冠状动脉介入(PCI)是主要的治疗手段,患者预后较好。结论:AMI发病年轻化,青年AMI患者中男性占绝大多数,病因以冠状动脉粥样硬化为主,其危险因素和冠状动脉病变特点与老年男性不同,临床医生应加以重视。  相似文献   
555.
BACKGROUND: Duchenne muscular dystrophy (DMD) is a progressive muscle disease caused by mutations in the dystrophin gene. Cardiomyopathy, conduction abnormalities, and ventricular arrhythmias are significant complications of this disease. The mdx ( 5cv ) mouse carries a dystrophin mutation and demonstrates a more severe phenotype than the classic mdx mouse. METHODS: Comprehensive electrophysiological phenotyping was performed in adult mdx ( 5cv ) and wildtype mice, including electrocardiography (ECG), implantable Holter monitoring, intracardiac electrophysiological testing, echocardiography, and exercise treadmill testing. RESULTS: ECG performed in mdx ( 5cv ) mice revealed significantly shorter PR intervals and prominent R waves in surface lead V1. During electrophysiological testing, mdx ( 5cv ) mice exhibited longer ventricle effective refractory periods and mildly increased ventricular tachycardia inducibility. There was no evidence for cardiomyopathy or ventricular dysfunction on echocardiography. Histopathology showed no increased myocardial fibrosis. Exercise endurance was lower in mdx ( 5cv ) mice without arrhythmias or other cardiac abnormalities. CONCLUSION: Taken together at the age range examined, mdx ( 5cv ) mice exhibit discrete cardiac electrophysiological dysfunction but display no evidence of structural or contractile abnormalities. Thus, the mdx ( 5cv ) mouse recapitulates some of the electrophysiological, but not hemodynamic cardiac defects present in human DMD. In certain settings, the mdx ( 5cv ) mouse may be an appropriate subject for studying electrical pathophysiology and therapy of the cardiac complications of DMD.  相似文献   
556.
目的:回顾性分析安贞医院急诊重症监护病房(EICU)中56例胸腔积液患者的特点及预后,评价对危重患者进行胸腔穿刺的必要性和安全性。方法:对比胸腔积液患者和无胸腔积液患者住院时间,住院费用及转归的差异;观察胸腔穿刺对诊断的影响及并发症。结果:2004年1月至2005年4月EICU收治患者328例,合并胸腔积液者56例,其中双侧积液30例,主要原因是心力衰竭和低蛋白血症,水负荷过重;单侧胸水26例,主要原因是肺癌和炎性胸腔积液。胸腔积液患者与无胸腔积液患者比较住院时间较长(P<0.05),住院费用较高(P<0.05),病死率无差异。34例行胸腔穿刺,其中10例与初步诊断不一致,误诊率29.4%。胸腔穿刺并发症少。结论:EICU中胸腔积液的发生率较高,出现胸腔积液延长住院时间,增加住院费用,但不影响病死率。  相似文献   
557.
Introduction: Recalls of implantable cardioverter defibrillator (ICD) generators have affected many patients. No information is available regarding the impact specifically on pediatric and congenital heart disease (CHD) patients. This study was undertaken to determine implications of ICD manufacturers’ advisories and recalls on children and CHD patients. Methods: The first part of this study involved single‐center review of patients who underwent ICD placement between 2000 and 2005. Patients with ICDs affected by the 2005 advisories/recalls were reviewed for incidence of explantation, malfunction and complications. Secondly, members of the Pediatric and Congenital Electrophysiology Society (PACES) were queried for patients with affected devices, incidences of explantation, malfunction, and explant‐related complications. Data were pooled for aggregate summary. Results: Among 233 patients who underwent ICD implantation at our institution during the study period, 58 (25%) patients had advisory/recalled devices and 13 of 58 (22%) underwent explantation following 3.1 ± 1.3 years implant duration. No defects were identified by the manufacturer. No patients experienced complications requiring reintervention or rehospitalization. Questionnaire responses were received from 22 PACES institutions, included 177 patients with affected devices, of which 76 (43%) were removed. One patient died from complications following revision, and 1 patient had complications requiring reoperation. Two explanted devices had loose headers; no other defects were discovered. Taken together, 2 of 89 explanted devices were defective, and 2 complications occurred from explantation. Conclusions: Advisories and recalls affect substantial numbers of pediatric and CHD patients. A significant proportion underwent explantation. Although complications are infrequent, there are important medical, psychosocial, and financial impacts associated with ICD replacement.  相似文献   
558.
目的 调查重庆市与西藏林芝地区碘缺乏病高危地区病情现状,为制订预防控制方案提供依据.方法 2007年由国家统一制订方案并抽样,重庆市调查城口和巫溪县,西藏林芝地区调查林芝、波密、米林和朗县4个县;林芝县抽查5个乡,其余县抽查3个乡;每个乡抽1所乡小学和2所村小学,以触诊和B超法同时检查8~10岁儿童甲状腺,同时检测尿碘;每个乡抽取2个村,每个村检测30户居民家庭食用盐含碘量,同时检测30名育龄妇女尿碘;搜索克汀病病例.结果 调查居民碘盐,重庆市调查340户,碘盐覆盖率98.82%(336/340);林芝地区调查915户,碘盐覆盖率为66.34%(607/905),重庆市高于林芝地区(x2=139.56,P<0.01).儿童甲状腺容积触诊和B超检查,重庆市儿童甲状腺肿大率分别为9.27%(89/960)和8.34%(61/731);林芝地区儿童甲状腺肿大率分别为7.80%(102/1308)和5.53%(69/1248),两地触诊法检查肿大率比较差异无统计学意义(x2=1.37,P>0.05),B超法重庆市高于林芝地区(x2=5.51,P<0.05);儿童尿碘中位数,重庆市为319.15μg/L,其中城口县为345.75μg/L,巫溪县为281.39 μg/L;林芝地区为189.81 μg/L,其中林芝县为207.81μg/L、波密县为161.12μg/L、米林县为131.83 μg/L、朗县为334.60μg/L;育龄妇女尿碘中位数重庆市为248.42μg/L,林芝地区为121.25μg/L,儿童和育龄妇女尿碘均以重庆市为高;重庆市和林芝地区均未发现新发克汀病病例.结论 重庆市和林芝地区碘缺乏病高危地区儿童甲状腺肿大率降至10%以下,未发现新发克汀病,防治成效显著.重庆市存在碘过量;西藏林芝县和朗县儿童存在碘过量,妇女存在碘不足,其原因有待进一步调查,波密和米林均存在碘不足.重庆市应降低食盐加碘量,林芝地区在进一步调查基础上调整补碘措施.
Abstract:
Objective To investigate iodine deficiency disorders(IDD) in Chongqing and Linzhi, and to provide scientific basis for IDD control and prevention. Methods According to the national program developed in 2007, investigation was conducted in Chengkou and Wuxi county in Chongqing municipality, and Linzhi, Bomi,Milin and Langxian county in Linzhi prefecture. Five towns were sampled in Linzhi county, and 3 in other counties.In each town, one township primary school and two village primary schools were selected to inspect thyroid by B ultrasound and palpation, and urinary iodine of children aged 8 to 10 years was tested in these schools. Meanwhile,2 villages were selected in each town for test of salt iodine level and urinary iodine of childbearing age women and search cretin cases. Results Three hundred and forty families in Chongqing and 915 families in Linzhi were investigated. The coverage of iodized salt in Chongqing was 98.82%(336/340), which was significantly higher than that in Linzhi[66.34%(607/905), x2 = 139.56, P < 0.01]. Goiter rate of children in Chongqing was 9.27%(89/960) by palpation and 8.34% (61/731) by B ultrasound, while goiter rate of children in Linzhi was 7.80%(102/1308) by palpation and 5.53% (69/1248) by B ultrasound. The difference of goiter rate by palpation between Chongqing and Linzhi was not statistically significant (x2 = 1.37, P > 0.05 ). But goiter rate of children by B ultrasound in Chongqing was higher than that in Linzhi (x2= 5.51, P < 0.05). In Chongqing, the median urinary iodine was 319.15 μg/L, and 345.75 μg/L in Chengkou county and 281.39 μg/L in Wuxi county. In Linzhi prefecture, the median urinary iodine was 189.81 μg/L, and 207.81 μg/L in Linzhi county, 161.12 μg/L in Bomi county, 131.83 μg/L in Milin county and 334.60 μg/L in Langxian county. The median urinary iodine in childbearing women were 248.42 μg/L in Chongqing and 121.25 μg/L in Linzhi. The median urinary iodine in Chongqing both in children and women were higher than those in Linzhi. No new cretin case was found in these two areas. Conclusions Goiter rate in high risk areas of IDD in Chongqing and Linzhi has decreased to less than 10%.No new cretin case is found in these areas. It can be concluded that the work of control and prevention is effective.There is excess iodine in Chongqing. In Linzhi county and Langxian county, iodine is excess in children and deficient in women. Further investigation should be conducted to find out the reason. Population iodine is excess in Bomi and Milin counties. The concentration of salt iodine should be decreased in Chongqing. In Linzhi prefecture,adding iodine measures should be adjusted based on further investigation.  相似文献   
559.
Loken  MR; Civin  CI; Bigbee  WL; Langlois  RG; Jensen  RH 《Blood》1987,70(6):1959-1961
The expression of two epitopes on glycophorin A (GPA) during erythroid development was examined on normal human bone marrow using quantitative flow cytometry. The highly correlated binding of two monoclonal antibodies, one sensitive and the other insensitive to glycosylation, indicated that the two epitopes were coordinately expressed during erythroid development. Both antigens reached a maximum expression during the early normoblast stage and were maintained at a constant amount per cell throughout further maturation to erythrocytes. These data suggest that glycosylation of GPA, as detected by antibodies recognizing blood group (M) and (N) antigens, does not increase during erythroid maturation.  相似文献   
560.
Although sarcomere protein gene mutations cause familial hypertrophic cardiomyopathy (FHC), individuals bearing a mutant cardiac myosin binding protein C (MyBP-C) gene usually have a better prognosis than individuals bearing beta-cardiac myosin heavy chain (MHC) gene mutations. Heterozygous mice bearing a cardiac MHC missense mutation (alphaMHC(403/+) or a cardiac MyBP-C mutation (MyBP-C(t/+)) were constructed as murine FHC models using homologous recombination in embryonic stem cells. We have compared cardiac structure and function of these mouse strains by several methods to further define mechanisms that determine the severity of FHC. Both strains demonstrated progressive left ventricular (LV) hypertrophy; however, by age 30 weeks, alphaMHC(403/+) mice demonstrated considerably more LV hypertrophy than MyBP-C(t/+) mice. In older heterozygous mice, hypertrophy continued to be more severe in the alphaMHC(403/+) mice than in the MyBP-C(t/+) mice. Consistent with this finding, hearts from 50-week-old alphaMHC(403/+) mice demonstrated increased expression of molecular markers of cardiac hypertrophy, but MyBP-C(t/+) hearts did not demonstrate expression of these molecular markers until the mice were >125 weeks old. Electrophysiological evaluation indicated that MyBP-C(t/+) mice are not as likely to have inducible ventricular tachycardia as alphaMHC(403/+) mice. In addition, cardiac function of alphaMHC(403/+) mice is significantly impaired before the development of LV hypertrophy, whereas cardiac function of MyBP-C(t/+) mice is not impaired even after the development of cardiac hypertrophy. Because these murine FHC models mimic their human counterparts, we propose that similar murine models will be useful for predicting the clinical consequences of other FHC-causing mutations. These data suggest that both electrophysiological and cardiac function studies may enable more definitive risk stratification in FHC patients.  相似文献   
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