首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 109 毫秒
1.
目的:研究缺血对豚鼠心室M细胞缓慢激活型延迟整流钾通道电流(Iks)的影响。方法:利用全细胞膜片钳技术观察豚鼠心室M细胞Iks,利用不同成分浴槽液模拟细胞正常及缺血坏死,观察Iks尾电流锋值的变化情况。结果:指令电压≥0mV时,缺血组电流显小于正常组,P<0.05;指令电压小于0mV时,两组间无显性差异,P>0.05。结论:缺血时M细胞Iks显减弱,可能会增加心室壁电活动不均一性,促使心律失常的发生。  相似文献   

2.
目的:研究缺血再灌注(ischemia/reperfusion,I/R)期间不同时相(缺血时、缺血后再灌时)氟比洛芬酯处殚对乳鼠心肌细胞钠电流的影响。方法:实验分为四组:1组(对照组)为体外培养乳鼠心室肌细胞;Ⅱ组(I/R组)为相同的细胞,缺血3小时,再灌注1小时;III组(氟比洛芬酯缺血时处理组)在I/R缺血时相加入氟比洛芬哺(0.15μM);IV组(氟比洛芬酯缺血后再灌注时处理组)在I/R再灌注时相加入氟比洛芬酯(0.15μM)。采用膜片钳全细胞模式分别记录并比较四组的钠电流。结果:和I组相比,II组存每一指令电压上都增大钠电流;在测试电压为-20mV的条件下,钠电流峰值电流密度从-375.47±70.31(pA/pF)增至-557.11±12786(pA/pF)(n=5,P〈f0.05);稳态激活半激活电压(V1/2)分别为-4281±1.21mV和-3149±2.40mV(n=5,P〈005);稳态欠活半激活电压(V1/2)分别为-7424±5.89mV和-68.70±6.26mV(n=5,P〈005);通道失活后恢复T分别为2569±19.47ms和7.534±3.24ms(n=5,P〈0.05)。III、IV组钠电流峰值电流密度从-375.47±70.31(pA/pF)分别降至-208.80±121.44和-278.91±188.26(pA/pF)(n=5,P〈0.05);通道稳念激活V1/2分别为-40.89±9.81mV和-39.49±3.70mV(n=5,P〉O05);稳态失活V1/2分别为74.45±5.02mY和-75494±3.32mV(n=5,P〉0.05);通道失活后恢复T分别为24.98±16.41ms和26.30±11.82ms(n=5,P〉005)。III、IV组之间各指标间的差异无统计学意义。结论:I/R处土型可以增大钠电流的峰值电流,并使电压电流曲线下移;减慢通道的时间依赖性激活,促进通道的电爪依赖性失活,失活后恢复变快。而在I/R缺血和再灌注两个时相使用氟比洛芬酯均能有效阻制钠通道的这螳改变。  相似文献   

3.
目的探讨缺血后处理(IPC)对大鼠心室肌细胞内向整流钾电流(IKI)和动作电位的影响及机制。方法实验分IPC组、缺血/再灌注(I/R)组、单纯灌流(SP)组,利用大鼠心脏建立离体灌注模型,采用胶原酶酶解法分离得到大鼠单心室肌细胞,采用膜片钳全细胞技术分别记录三组心室肌细胞电流和动作电位的变化。结果在-120mV和-30mV刺激电压水平,IKI电流密度:IPC组低于I/R组,I/R组高于SP组(P均〈0.05),IPC组同SP组无差异(P〉0.05)。与SP组和IPC组比较,I/R组静息电位明显升高(P〈0.05);而动作电位幅度、20%动作电位时程、50%动作电位时程、90%动作电位时程均明显下降(P〈0.05)。而IPC组各值与SP组无差异(P〉0.05)。结论IPC可以降低大鼠缺血/再灌注心肌细胞IKI延长缺血/再灌注心肌细胞APD。  相似文献   

4.
目的 探讨卡托普利对豚鼠心室肌细胞动作电位及外向延迟整流钾电流的作用。方法 采用内充3M KCL的标准微电极记录心肌动作电位。采用膜片钳全细胞技术,钳制电位-50mV,持续时间100ms,指令电位 40mV,记录外向延迟整流钾电流(Ik)最大峰电流。结果 与缺血组比较,卡托普利组APD30、APD50及ERP显著延长,APD50无显著变化。缺血组Ik幅度显著增高,而卡托普利组及卡托普利 缺血组显著降低。各组电流—电压关系曲线形态虽无显著变化,但缺血组显著上移,而卡托普利组、卡托普利 缺血组比缺血组下移。结论卡托普利降低外向钾电流及延长APD30、APD50和ERP。  相似文献   

5.
目的研究慢性压力超负荷左室电重构的异质性及离子基础。方法新西兰兔通过肾上腹主动脉次全结扎诱发左室慢性压力超负荷。采用全细胞膜片钳技术分别记录对照组及手术组左室内膜、中层及外膜细胞的动作电位,慢激活的延迟整流钾电流(IKs)及快激活的延迟整流钾电流(IKr)等。结果与对照组比较,基础周长为2S时,手术组左室内膜、中层及外膜细胞的动作电位复极90%的时程(APD90)分别延长27.7%、27.2%(P〈0.05或0.01)、19.6%(P〉0.05);对照组中层细胞的APD90较外膜细胞长50.8%,而手术组为60.4%;在测试电位为+50mV时,手术组左室内膜、中层及外膜细胞IKs尾电流密度分别减小26.1%、36.3%(P均〈0.05)、23.0%(P〉0.05);IKr尾电流密度分别减小31.7%、30.5%、30.0%(P〈0.01或0.05)。对照组外膜细胞的IKs尾电流密度较中层细胞大49.1%,而手术组为77.6%;两组三层细胞之间IKr尾电流密度均无差别。结论正常兔左室存在跨壁复极异质性,心肌肥厚时进一步扩大,IKs分布及下调的不均一性是其离子流基础。  相似文献   

6.
目的:研究急性缺氧对大鼠肺动脉平滑肌细胞电压门控钾通道(Kv)电流的影响。方法:雄性SD大鼠20只随机分为常氧对照组和急性缺氧组(各10只)。急性缺氧组大鼠在低氧仓中缺氧停留8h后进行实验。应用全细胞膜片钳技术记录肺动脉平滑肌细胞电压门控钾通道电流(Ik)。结果:急性缺氧显著降低大鼠肺动脉平滑肌细胞的Ik密度。在大鼠肺动脉平滑肌细胞静息膜电位-60mV至-10mV时,急性缺氧降低大鼠肺动脉平滑肌细胞的IK密度不明显(P〉0.05)。在0mV时,大鼠肺动脉平滑肌细胞的峰值Ik密度显著下降[从(38.1±5.2)pA/pF→(9.82±2.1)pA/pF,P〈0.05)],此后随着细胞静息膜电位的增加,平滑肌细胞的Ik密度下降幅度逐渐增加(P〈0.05);从+30mV至+60mV时,平滑肌细胞的Ik密度下降幅度更大(P〈0.01)。在+60mV时,IK密度峰值从(135.4±16.5)pA/pF降到(73.1±10.6)pA/pF,降幅达(46.8±3.3)%。结论:急性缺氧可降低肺动脉平滑肌细胞Kv电流,导致肺血管缺氧性收缩。  相似文献   

7.
目的 研究心室M层起搏对犬跨室壁复极离散(TDR)的影响,探讨采用心室M层起搏技术防治跨室壁复极离散增大相关性心律失常的可行性.方法 制作犬左心室楔形心肌组织块模型,观察心内、外膜及M层起搏时,各层心肌动作电位时限(APD)及TDR的变化.结果 分别行心室肌内、外膜和M层起搏,心肌各层APD差异无统计学意义(P>0.05);但M层起搏时,TDR较外膜起搏明显减小[(34.9±5.4)ns对(71.5±6.1)ms,P<0.01];与内膜起搏相比差异无统计学意义[(34.9±5.4)ms对(35.9±5.4)ms,P>0.05].结论 与心外膜起搏相比,M层起搏可有效减小TDR;但与心内膜起搏相比,差异无统计学意义.  相似文献   

8.
目的:通过比较急性冠状动脉综合征(ACS)患与健康正常人血浆C-反应蛋白(CRP)浓度的变化。探讨炎症反应在ACS发病所起的作用。方法:对23例急性心肌梗死(AMI)和36例不稳定型心绞痛(UAP)患在急性发病时测定血浆CRP浓度,并行24h动态心电图检查记录缺血总负荷。结果:AMI和UAP患血浆CRP浓度明显比健康正常人高(P>0.01),缺血总负荷大于1000mm.min与小于1000mm.min ACS患中血浆CRP浓度无显性差异(P>0.05)。结论:CRP与冠状动脉(冠脉)斑块活动有关。与心肌缺血的程度无关,炎症的应是导致ACS发生的原因之一。  相似文献   

9.
目的 通过检测慢活化电压依赖性外向钾离子通道电流(Iks)的变化,探讨生长抑素及质子泵抑制剂(PPI)对胰腺腺泡细胞慢活化电压依赖性钾离子通道及胰腺外分泌的影响.方法 分离SD大鼠胰腺组织,取得胰腺腺泡细胞悬液,用EPC10膜片钳放大器记录电压钳制下的不同组别胰腺腺泡细胞Iks的电流值并比较其间差异.分组如下:冲洗液处理为对照组,5μmol/L和20μmol/L 293B组,5 nmol/L促胰液素组,5 nmol/L促胰液素+100 nmol/L或10 nmol/L或1 nmol/L生长抑素组,0.3 mmol/L 8溴—环单磷酸腺苷(8Br-cAMP)组,0.3 mmol/L 8Br-cAMP+100 nmol/L生长抑素组,1 μmol/L乙酰胆碱(Ach)组,1μmol/L Ach+100 nmol/L生长抑素组,5 nmol/L促胰液素+10-5mol/L或10-6mol/L或10-7mol/L奥美拉唑组,1μmol/L Ach+10-5 mol/L或10-6 mol/L或10-7 mol/L奥美拉唑组.组间比较采用单因素方差分析,P<0.05为差异有统计学意义.结果 大鼠胰腺腺泡细胞静息膜电位为(-40±0.8)mV,当去极化至+10 mV时,对照组的Iks为(420.0±3.2) pA.经5 μmol/L和20 μmol/L 293B作用后,大鼠胰腺腺泡细胞Iks减少为对照组的(60.4±4.2)%和(30.2±3.1)%(F=6.87,P<0.05).5 nmol/L促胰液素刺激后,Iks增加为(823.0±2.2)pA,分别加入100 nmol/L、10 nmol/L和1 nmol/L生长抑素,Iks降低至(510.0±3.2)pA,(584.0±2.8)pA和(789.0±6.9)pA(F=5.67,P<0.05);分别加入10-5 mol/L、10-6 mol/L和10-7mol/L奥美拉唑后,Iks峰值未见明显变化,分别为(806.5±3.6)pA,(814.8±3.2) pA和(816.3±2.9) pA (P>0.05).1 μmol/L Ach刺激后,Iks的峰值为(966.0±3.2) pA;加入100 nmol/L生长抑素后,Iks峰值为(942.0±6.3)pA;分别加入10-5 mol/L,10-6 mol/L和10-7 mol/L奥美拉唑后,其Iks峰值未见明显变化,分别为(956.3±10.3) pA,(957.5±8.6)pA和(960.0±8.4)pA (P>0.05).结论 生长抑素能抑制胰腺腺泡细胞慢活化电压依赖性钾离子通道的开放,PPI对该通道没有明显抑制作用.  相似文献   

10.
目的:观察西洛他唑对大鼠右心室肌细胞离子通道的影响,探讨西洛他唑预防Brugada综合征室性心律失常发生的离子通道机制。
  方法:本研究包括两部分实验:①灌流实验,分为1、2、5、50μmol/L西洛他唑组,每组记录的细胞数分别为9、5、3、7个。分别观察每组给药前后瞬间外向钾电流(Ito)电流密度的变化,并观察四组间用药前后Ito电流密度变化的差异;②口服药物实验,分为空白1组、实验1组、空白2组、实验2组,每组选用的大鼠数分别为7、5、8、6只,分别观察实验组与空白组Ito、L-型钙电流(ICa,L)电流密度的差异。
  结果:灌流实验结果:①在1、2、5、50μmol/L西洛他唑各组中,细胞灌流药物后Ito电流密度均降低,在自指令电压+60 mV时,各组用药前后的Ito电流密度差异有统计学意义(P均<0.05)。②在各指令电压下时,不同浓度西洛他唑灌流液灌流细胞后Ito电流密度减少率,四组间差异均无统计学意义(P均>0.05)。口服药物实验结果:①在自指令电压-50 mV到最大+60 mV,实验1组Ito电流密度较空白1组无明显变化,差异无统计学意义(P>0.05);②在自指令电压为+10 mV,空白2组ICa,L电流密度较实验2组略高,但差异无统计学意义(P>0.05)。
  结论:1、2、5、50μmol/L西洛他唑灌流液直接作用于大鼠右心室肌细胞,均能明显的抑制Ito,但西洛他唑1~50μmol/L范围内对Ito的抑制程度没有差异。西洛他唑可能具有抑制Brugada综合征心律失常发生的作用。  相似文献   

11.
目的胰岛素瘤是最常见的胰腺神经内分泌肿瘤,因其临床表现多样,导致诊断困难。影像学诊断尤其是超声内镜(EUS)在胰岛素瘤的诊断中起着重要作用,拥有较高的敏感性和特异性。本研究拟通过明确胰岛素瘤的解剖分布特点,以期有助于提高影像学的诊断准确率和降低漏诊率,尤其是在教育和培训实践中对于EUS的学习者更具有指导价值。 方法回顾性分析解放军总医院第一医学中心病案资料数据库1993年1月至2019年11月经外科手术、病理确诊为胰岛素瘤的患者的临床资料,检索方法采取搜索术后病理诊断为"胰岛素瘤"的病例,通过查阅病例的方法,提取出胰岛素瘤的大小和解剖分布等数据,进一步分析其特点。 结果共检索到确诊为胰岛素瘤的患者116例,其中,男45例、女71例,年龄13~76岁,平均年龄(44.4±14.85)岁。胰岛素瘤单发110例(94.8%)、多发6例(5.2%)。位置分布:头颈部46例(39.7%),单发45例、多发1例;体尾部68例(58.6%),单发65例、多发3例;全胰腺多发2例(1.7%)。病变大小特点:最大径0.4~3.4 cm,平均大小(1.53±0.58)cm。≤1 cm 29例、>1 cm而≤1.5 cm41例、>1.5 cm而≤2.0 cm28例,≤3 cm 15例,>3 cm 3例。年龄与肿瘤的大小相关,≤44岁患者肿瘤平均大小为(1.36±0.51)cm、>44岁患者肿瘤平均大小为(1.70±0.60)cm,P<0.05。头颈部的肿瘤大于体尾部的肿瘤,头颈部肿瘤平均大小(1.66±0.63)cm,体尾部(1.42±0.52)cm,P<0.05。 结论胰岛素瘤在胰腺体尾部较头颈部更好发;绝大多数单发,但可以全胰腺多发;多数小于1.5 cm,肿瘤的大小与患者年龄和肿瘤的解剖分布相关。  相似文献   

12.
Most adenomas and carcinomas of the small intestine and extrahepatic bile ducts arise in the region of the papilla of Vater. In familial adenomatous polyposis (FAP) it is the main location for carcinomas after proctocolectomy. In many cases symptoms due to stenosis lead to diagnosis at an early tumor stage. In about 80%, curative intended resection is possible. Operability is the most relevant prognostic factor. Most ampullary carcinomas resp. carcinomas of the papilla of Vater develop from adenomatous or flat dysplastic precursor lesions. They can be sited in the ampulloduodenal part of the papilla of Vater, which is lined by intestinal mucosa. They also can develop in deeper parts of the ampulla, which are lined by pancreaticobiliary duct mucosa. Intestinal-type adenocarcinoma and pancreaticobiliary-type adenocarcinoma represent the main histological types of ampullary carcinoma. Furthermore, there exist unusual types and undifferentiated carcinomas. Many carcinomas of intestinal type express the immunohistochemical marker profile of intestinal mucosa (keratin 7?, keratin 20+, MUC2+). Carcinomas of pancreaticobiliary type usually show the immunohistochemical profile of pancreaticobiliary duct mucosa (keratin 7+, keratin 20?, MUC2?). Even poorly differentiated carcinomas, as well as unusual histological types, may conserve the marker profile of the mucosa they developed from. These findings underline the concept of histogenetically different carcinomas of the papilla of Vater which develop either from intestinal- or from pancreaticobiliary-type mucosa of the papilla of Vater. Molecular alterations in ampullary carcinomas are similar to those of colorectal as well as pancreatic carcinomas, although they appear at different frequencies. In future studies, molecular alterations in ampullary carcinomas should be correlated closely with the different histologic tumor types. Consequently, the histologic classification should reflect the histogenesis of ampullary tumors from the two different types of papillary mucosa.  相似文献   

13.
Summary Palmitic acid oxidation in rat diaphragm homogenate is depressed by biguanide concentrations that are still incapable of inhibiting oxidative phosphorylation. Glucose oxidation is not directly effected by the same biguanide concentrations: however, the inhibitory effect of palmitic acid on glucose oxidation is partly removed by biguanides. Inhibition of fatty acid oxidation, which accounts for most of the metabolic effects caused by these drugs, can be regarded as the fundamental mechanism of action of biguanides. There is some evidence suggesting that these drugs might interact with carnitine, thus preventing long-chain fatty acids from being transported across the mitochondrial membrane to the site of oxidation. Traduzione a cura degli AA.  相似文献   

14.
BACKGROUND AND AIM: Both the clinical presentation and the degree of mucosal damage in coeliac disease vary greatly. In view of conflicting information as to whether the mode of presentation correlates with the degree of villous atrophy, we reviewed a large cohort of patients with coeliac disease. PATIENTS AND METHODS: We correlated mode of presentation (classical, diarrhoea predominant or atypical/silent) with histology of duodenal biopsies and examined their trends over time. RESULTS: The cohort consisted of 499 adults, mean age 44.1 years, 68% females. The majority had silent coeliac disease (56%) and total villous atrophy (65%). There was no correlation of mode of presentation with the degree of villous atrophy (p=0.25). Sixty-eight percent of females and 58% of males had a severe villous atrophy (p=0.052). There was a significant trend over time for a greater proportion of patients presenting as atypical/silent coeliac disease and having partial villous atrophy, though the majority still had total villous atrophy. CONCLUSIONS: Among our patients the degree of villous atrophy in duodenal biopsies did not correlate with the mode of presentation, indicating that factors other than the degree of villous atrophy must account for diarrhoea in coeliac disease.  相似文献   

15.
氯硝柳胺悬浮剂的毒性评价   总被引:2,自引:2,他引:2  
目的评价氯硝柳胺悬浮剂的毒性,为现场大规模应用灭螺提供依据。方法按照中华人民共和国国家标准GB 15670-1995《农药登记毒理学试验方法》和鱼类毒性试验方法进行。结果经口、经皮肤的LDso雌、雄性大鼠均>5 000 mg/kg,经呼吸道的LCso雌、雄性大鼠均>5 000mg/m3,该药经口、经皮肤、经呼吸道毒性均属微毒类药物;兔眼用药后,观察期内无不良反应,对眼无刺激性;皮肤用药后对皮肤无刺激性。与氯硝柳胺原药、氯硝柳胺乙醇胺盐原药和氯硝柳胺乙醇胺盐可湿性粉剂相比,氯硝柳胺悬浮剂对鱼急性毒性最低。结论氯硝柳胺悬浮剂属微毒类药物,对鱼的毒性低于其乙醇胺盐可湿性粉剂,适合于现场应用。  相似文献   

16.
血吸虫童虫是宿主免疫系统攻击的重要靶标,包括皮肤型、肺型和肝门型童虫。宿主分子对童虫生长发育具有重要作用。童虫生长发育机制包括免疫调节、信号转导、性别发育及凋亡等。肌动蛋白、组织蛋白酶、烯醇化酶和葡萄糖基转移酶等分子为血吸虫童虫生长发育的重要分子。本文对血吸虫童虫生长发育及其机制的研究进展做一综述。  相似文献   

17.
目的对临床分离的耐多药结核分枝杆菌相关基因的突变特征进行分析。方法对124例耐多药结核分枝杆菌以及50株敏感株的耐药相关基因(包括异烟肼inh A、kat G、oxyR-ahp C间隔区以及利福平rpo B)进行序列测定,分析其基因突变情况。结果异烟肼耐药inh A基因突变率为14.5%;kat G基因突变率为70.2%(87/124),主要位于315位;oxyR-ahp C间隔区突变率为15.3%;inh A、kat G两种基因同时突变率75.0%,三种基因同时突变率为89.5%。利福平rpo B基因突变的检出率高达95.2%,突变主要发生在531、526、516位点。结论我省耐多药菌异烟肼耐药相关基因最常见突变为kat G 315、inh A C-T(-15)、axyR-ahp C间隔区(-10)C-T,利福平为rpo B531、526、516。结合MDR-TB耐药相关基因的特征分析,可以建立一种快速、准确、特异的适合于我省的检测结核菌耐多药性的新方法。  相似文献   

18.
The aim of the study was to assess the quality of life (QOL) and the psychological status of parents of children with juvenile chronic arthritis (JCA). The QOL, anxiety and depression of the parents of 28 children with JCA were evaluated and compared to those of the parents of 28 healthy children. Mothers of JCA children and mothers of healthy children reported similar QOL. The reported anxiety and depression levels were similar for mothers and fathers in both groups. The parents of children with pauciarticular-type JCA reported lower QOL and higher levels of anxiety and depression than the parents of children with other types, namely polyarticular and systemic JCA. These findings may be explained by the fact that the pauciarticular patients had shorter disease duration and were less frequently seen in the outpatient clinic. The QOL of mothers of children with JCA was found to be slightly impaired in the group of children with pauciarticular JCA. Future larger studies are needed to confirm these results, as the number of subjects in the three groups was rather low. Received: 26 September 2001 / Accepted: 8 February 2002  相似文献   

19.

Background

A 5-day in-patient study designed to assess the accuracy of the FreeStyle Navigator® Continuous Glucose Monitoring System revealed that the level of accuracy of the continuous sensor measurements was dependent on the rate of glucose change. When the absolute rate of change was less than 1 mg•dl−1•min−1 (75% of the time), the median absolute relative difference (ARD) was 8.5%, with 85% of all points falling within the A zone of the Clarke error grid. When the absolute rate of change was greater than 2 mg•dl−1•min−1 (8% of the time), the median ARD was 17.5%, with 59% of all points falling within the Clarke A zone.

Method

Numerical simulations were performed to investigate effects of the rate of change of glucose on sensor measurement error. This approach enabled physiologically relevant distributions of glucose values to be reordered to explore the effect of different glucose rate-of-change distributions on apparent sensor accuracy.

Results

The physiological lag between blood and interstitial fluid glucose levels is sufficient to account for the observed difference in sensor accuracy between periods of stable glucose and periods of rapidly changing glucose.

Conclusions

The role of physiological lag on the apparent decrease in sensor accuracy at high glucose rates of change has implications for clinical study design, regulatory review of continuous glucose sensors, and development of performance standards for this new technology. This work demonstrates the difficulty in comparing accuracy measures between different clinical studies and highlights the need for studies to include both relevant glucose distributions and relevant glucose rate-of-change distributions.  相似文献   

20.
治疗高血压药物的经济学评价   总被引:3,自引:0,他引:3  
重视高血压治疗中的经济学评价,对利用我国有限的卫生资源来遏制高血压对人民群众的危害有着重要的现实意义。药物经济学对于药物治疗的成本和治疗的结果给予同样的关注。因为治疗高血压的费用,不仅涉及药物价格,还包括患者的危险水平,降压疗效和对临床终点事件的影响,以及治疗的依从性和安全性。因此药物经济学更强调整体成本和价-效比。低危病人,若非药价低廉,治疗的价-效比不够理想。而在高危的患者,价-效比越小越经济而不是药费越便宜越好。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号