阿托伐他汀对THP-1源性巨噬细胞CD40及MMP-9的抑制作用

目的观察他汀类药物对人单核/巨噬细胞(THP-1细胞)基质金属蛋白酶-9(MMP-9)的表达是否存在抑制作用及其作用是否与CD40-CD40L信号通路有关,探讨他汀类药物可能的非调脂抗动脉粥样硬化机制。方法先加入不同浓度的阿托伐他汀(1.25μmol/L、2.50μmol/L、5.00μmol/L)作用1h,再向培养的THP-1细胞中加入氧化型低密度脂蛋白(80mg/L)共同孵育24h,分别运用反转录聚合酶链反应(RT-PCR)法检测CD40及MMP-9mRNA,酶联免疫吸附测定法(ELISA)测定培养基的MMP-9浓度。结果阿托伐他汀抑制THP-1细胞CD40和MMP-9mRNA的表达,同时抑制MMP-9蛋白的表达(P<0.05),并呈浓度依赖性。结论阿托伐他汀能抑制THP-1细胞CD40的表达以及MMP-9的表达和分泌,这种作用可能是他汀类药物减轻动脉粥样斑块炎症,防止斑块破裂的机制之一。     

西立伐他汀对血管内皮细胞一氧化氮合酶及细胞间黏附分子的作用

目的　观察西立伐他汀对内皮细胞一氧化氮合酶 (NOsythase ,eNOS)和细胞间黏附分子 1 (intercellularadhesionmolecule 1 ,ICAM 1 )基因的表达 ,NOS活力和黏附的THP 1细胞量的影响。方法　以氧化LDL抑制培养的ECV 3 0 4细胞表达eNOS ,加入不同浓度西立伐他汀后 ,用RT PCR法检测eNOSmRNA ,硝酸还原酶法测定培养基中NO量。以脂多糖 (LPS)及西立伐他汀加入ECV 3 0 4细胞后 ,用RT PCR法检测ICAM 1mRNA ,并测定黏附的THP 1细胞量。结果　随着西立伐他汀浓度增加 ,内皮细胞eNOSmRNA水平增加 ,0 0 1 ,0 1 ,1 0 μmol/L时分别增加 5 0 %,1 5 0 %,3 0 0 %,P均 <0 0 5。培养液中NO亦相应增加 ,0 0 1 ,0 1 ,1 0 μmol/L时分别增加 2 6 7%,92 3 %,2 3 0 %,P <0 0 5。西立伐他汀浓度为 0 1 ,1 0 μmol/L时 ,ICAM 1mRNA分别从 70 7± 1 0 4降至 5 6 2± 6 5 ,3 5 8± 4 2 ,P <0 0 5。黏附于ECV 3 0 4细胞的THP 1细胞在 1 0 μmol/L时被抑制 2 6 %,P <0 0 5。结论　西立伐他汀能诱导内皮细胞eNOS基因的表达及增加NOS活力 ;抑制内皮细胞表达ICAM 1mRNA及THP 1细胞黏附于内皮细胞     

西立伐他汀对THP-1细胞CD40和基质金属蛋白酶9表达的影响

通过观察他汀类药物对单核细胞CD4 0和基质金属蛋白酶 9的表达是否存在抑制作用 ,初步探讨他汀类药物可能的非调脂的抗动脉粥样硬化机制。将培养的THP 1细胞中加入不同浓度的西立伐他汀 ,运用RT PCR法检测CD4 0及基质金属蛋白酶 9mRNA ,酶联免疫吸附测定法测定培养基的基质金属蛋白酶 9的浓度。结果发现 ,西立伐他汀抑制THP 1细胞CD4 0和基质金属蛋白酶 9mRNA的表达 ,并呈浓度依赖性。西立伐他汀在 0 .0 1μmol L时 ,CD4 0及基质金属蛋白酶 9的表达无明显降低 ,但在 1和 10 μmol L时 ,CD4 0mRNA的表达下调 5 5 %、89% ,基质金属蛋白酶 9mRNA的表达亦明显下降 (0 .4 5 3± 0 .13比 0 .0 73± 0 .0 1和 0 .0 0 9± 0 .0 0 1)。培养基的基质金属蛋白酶 9浓度在西立伐他汀 1和 10 μmol L时分别从 0 .4 6 9± 0 .0 6降低至 0 .2 4 3± 0 .0 4和 0 .0 39± 0 .0 1(P <0 .0 5 )。结果提示 ,西立伐他汀能抑制THP 1细胞CD4 0表达以及基质金属蛋白酶的表达和分泌 ,提示他汀类药物可减轻动脉粥样斑块炎症 ,防止斑块破裂 ,从而减少急性冠状动脉事件的发生。     

氧化低密度脂蛋白对人单核细胞组织因子和基质金属蛋白酶-9活性的影响以及阿托伐他汀的干预作用

目的:探讨他汀类降脂药阿托伐他汀潜在的降脂外机制。方法:人单核细胞来源的巨噬细胞,加入50mg/L氧化低密度脂蛋白(oxLDL)共培养10d,加或不加入不同浓度的阿托伐他汀(浓度范围0.01~0.5μmol/L);酶谱学分析基质金属蛋白酶-9(MMP-9)的活性;一期凝固法测定组织因子(TF)的促凝活性。结果:阿托伐他汀可抑制单核-巨噬细胞的增殖,呈现一定的剂量依赖关系(P<0.05),加入100μmol/L羟甲戊酸后,这种抑制作用消失;0.1μmol/L的阿托伐他汀可显著抑制单核-巨噬细胞表达MMP-9的活性;阿托伐他汀可呈剂量依赖性抑制TF的促凝活性(P<0.05)。结论:阿托伐他汀不仅可抑制单核-巨噬细胞的增殖,而且可抑制单核巨噬细胞活化下表达的MMP-9的活性以及TF的促凝活性。     

阿托伐他汀对人NK细胞杀伤HCT-116细胞的影响及其机制研究

目的探讨阿托伐他汀对人自然杀伤细胞(natural killer,NK)杀伤HCT-116细胞的影响及其机制。方法 CCK-8法测定不同浓度的阿托伐他汀对HCT-116细胞生长抑制率的影响。自动生化分析仪测NK细胞对HCT-116细胞的杀伤活性;流式细胞仪(FCM)检测HCT-116细胞MICA/B的表达率。结果不同浓度的阿托伐他汀作用于HCT-116细胞48 h后在浓度为5~40μmol/L及作用96 h后在浓度为1.25~40μmol/L时,对HCT-116细胞的生长抑制率与对照组相比差异有统计学意义(P0.05)。阿托伐他汀浓度相同时,HCT-116细胞的生长抑制率在48 h组与96 h组相比,除5μmol/L浓度组外差异均有统计学意义(P0.05)。阿托伐他汀的浓度与HCT-116细胞的生长抑制率呈正相关(r[48 h]=0.13,r[96 h]=0.22,P0.05)。NK细胞对HCT-116细胞的杀伤活性在阿托伐他汀浓度为2.5~10μmol/L各组中均显著高于对照组(P0.05)。2.5μmol/L浓度组及5μmol/L浓度组,HCT-116细胞MICA/B的表达率与对照组比较显著升高(P0.05)。结论阿托伐他汀呈剂量依赖性抑制HCT-116细胞的生长,且延长作用时间可以增强阿托伐他汀对HCT-116细胞生长的抑制作用;还能够增强NK细胞对HCT-116杀伤活性;以及上调HCT-116细胞MICA/B的表达率,提高其免疫原性。     

阿托伐他汀对同型半胱氨酸诱导的心肌细胞MEK/ERK通路及心肌线粒体损伤的影响

目的探讨阿托伐他汀对同型半胱氨酸(Hcy)诱导的心肌细胞H9c2丝裂原细胞外信号调节激酶(MEK)/细胞外调节蛋白激酶(ERK)通路及心肌线粒体损伤的影响。方法细胞计数试剂盒8(CCK-8)检测不同浓度Hcy对H9c2细胞存活率的影响,筛选Hcy诱导浓度和时间。将诱导后的H9c2细胞分为模型组、5μmol/L阿托伐他汀组、10μmol/L阿托伐他汀组和15μmol/L阿托伐他汀组,另取正常H9c2细胞为对照组。流式细胞仪检测各组细胞凋亡率;JC-1法检测各组细胞线粒体膜电位的变化;DCFH-DA法检测各组细胞内活性氧(ROS)水平;酶联免疫吸附法(ELISA)检测各组细胞中丙二醛(MDA)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)含量;Western blot检测各组细胞MEK1/2和ERK1/2磷酸化水平。结果与对照组相比,2μmol/L Hcy可显著降低H9c2细胞存活率(P0.05),本研究使用2μmol/L Hcy处理24 h诱导H9c2细胞。与对照组相比,模型组H9c2细胞凋亡率、ROS水平、MDA含量显著升高(P0.05),线粒体膜电位、SOD、CAT含量及MEK1/2、ERK1/2磷酸化水平显著降低(P0.05);与模型组相比,5μmol/L阿托伐他汀组、10μmol/L阿托伐他汀组和15μmol/L阿托伐他汀组H9c2细胞凋亡率、ROS水平、MDA含量依次降低(P0.05),线粒体膜电位、SOD、CAT含量及MEK1/2、ERK1/2磷酸化水平依次升高(P0.05)。结论阿托伐他汀可能通过激活MEK/ERK通路降低Hcy诱导的H9c2细胞氧化应激反应,减轻心肌线粒体损伤。     

阿托伐他汀对THP-1源性巨噬细胞自体吞噬的影响

目的 观察阿托伐他汀对THP-1源性巨噬细胞自体吞噬(自噬)的影响.方法 用Hank's液代替常规培养液的饥饿诱导的方法使THP-1源性巨噬细胞发生自噬,在诱导自噬过程中,使细胞分别与含有低浓度(1μmol/L)和高浓度(5μmol/L)阿托伐他汀钙的培养液共同孵育,以空白组作对照,运用间接免疫荧光染色法,采用荧光显微镜观察LC3-FITC点状聚集情况,应用透射电镜观测各组细胞自噬的发生情况.结果 与对照组相比,两组合阿托伐他汀钙培养液的巨噬细胞中的自噬泡占胞质总面积均明显增多(P＜0.05),高浓度阿托伐他汀组自噬泡占胞质总面积高于低浓度阿托伐他汀组,但无显著性差异(P =0.079).结论 阿托伐他汀钙可以促进THP-1源性巨噬细胞自噬.     

阿托伐他汀通过上调大电导钙敏感钾通道电流影响大鼠主动脉平滑肌细胞膜电位研究

目的探讨阿托伐他汀通过上调大电导钙敏感钾通道(BKca)电流影响大鼠主动脉平滑肌细胞(ASMCs)膜电位机制。方法浓度分组:生理盐水对照组、阿托伐他汀浓度分别为10、25、50、100、150μmol/L细胞共培养组。应用+/-BKca通道阻断剂iberiotoxin(IBTX,100 nmol/L)时通过激光共聚焦显微镜检测ASMCs膜电位;全细胞膜片钳技术检测ASMCs全细胞钾电流密度(pA/pF)。结果ASMCs与阿托伐他汀共培养后细胞膜电位荧光值下降,呈阿托伐他汀浓度依赖性;与对照组比较,100μmol/L及150μmol/L阿托伐他汀组荧光值下降,有统计学意义(P0.05)。对照组中加入IBTX明显降低pA/pF值(P0.05);与对照组比较,阿托伐他汀共培养组pA/pF值增加,有统计学意义(P0.05);而100μmol/L阿托伐他汀+IBTX组电流密度变化无统计学意义(P0.05)。与100μmol/L阿托伐他汀组比较,100μmol/L阿托伐他汀+IBTX组pA/pF值减小,有统计学意义(P0.05)。结论阿托伐他汀上调BKca通道电流导致ASMCs超极化,进而影响血管平滑肌细胞生物学活性。     

阿托伐他汀对氧化型低密度脂蛋白诱导的人脐静胁内皮细胞增殖及白细胞介素-18分泌的影响

目的:观察阿托伐他汀对氧化型低密度脂蛋白(ox-LDL)诱导的人脐静脉内皮细胞(HUVEC)增殖及白细胞介素-18(IL-18)分泌的影响.方法:体外培养的HUVEC株,第3～9代用于实验.实验分3组:①空白对照组;②ox-LDL组(100 mg/L);③阿托伐他汀组:先将阿托伐他汀0.01、0.05、0.1、0.5、1.0μmol/L分别,作用于内皮细胞4 h,然后加ox-LDL(100 mg/L)作用细胞24 h.采用细胞酶联免疫吸附分析检测细胞培养上清液IL-18含量;采用四唑盐比色法检测各孔的吸收度(OD),以评价增殖效果.结果:与空白对照组比较,100 mg/L ox-LDL抑制内皮细胞增殖(P＜0.01),阿托伐他汀呈剂量依赖性地促进ox-LDL诱导的内皮细胞增殖(P＜0.05,P＜0.01).正常内皮细胞不分泌IL-18,而100 mg/L ox-LDL促进IL-18分泌.0.01/μmol/L阿托伐他汀对ox-LDL诱导的HUVEC分泌IL-18无影响(P＞0.05),0.05,0.1,0.5,1.0 μmol/L阿托伐他汀能明显抑制oxLDL诱导的HUVEC分泌IL-18(P＜0.05,P＜0.01),抑制效应呈浓度依赖性.结论:阿托伐他汀呈剂量依赖性地抑制ox-LDL诱导的人HUVECs分泌IL-18,促进内皮细胞增殖,保护内皮功能,从而发挥他汀类药物调脂外抗动脉粥样硬化作用.     

阿伐他汀对自发性高血压大鼠心肌成纤维细胞增殖及胶原合成的影响

目的探讨阿伐他汀(atorvastatin)对培养的自发性高血压大鼠 (spontaneous hypertensive rats,SHR)和正常血压Wistar大鼠心肌成纤维细胞(cardiac fibroblasts , CFs)增殖和胶原合成的影响.方法采用胰酶消化法培养CFs,用四甲基偶氮唑蓝(MTT)比色法测定细胞增殖,流式细胞分析仪(FCM)技术检测细胞周期,ELISA法检测Ⅰ型胶原合成.结果 (1)10-7 mol/L、10-6 mol/L、10-5 mol/L 和10-4 mol/L阿伐他汀作用后MTT比色法A比值SHR组分别为0.30±0.01、0.26±0.01、0.24±0.01 和0.22±0.01,与对照组(0.33±0.01)比较差异非常显著(P均<0.01);Wistar大鼠组分别为0.28±0.01、0.26±0.01、0.23±0.01 和 0.21±0.01,与对照组 (0.30±0.01)相比差异非常显著(P均<0.01).(2) 10-6 mol/L 阿伐他汀作用48 h,SHR和Wistar大鼠CFs的G0/G1期细胞百分率均较对照组显著增高(P均<0.01),S期细胞百分率、G2/M期细胞百分率和增殖指数(proliferation index, PI)则较对照组显著降低(P均<0.01).(3)随着阿伐他汀浓度的增高,CFs的Ⅰ型胶原分泌呈明显的递减趋势.10-7mol/L、10-6mol/L、10-5mol/L 和10-4 mol/L阿伐他汀作用后Ⅰ型胶原,SHR分别为0.71±0.01、0.70±0.01、0.63±0.01 和0.58±0.02,均显著低于对照组0.88±0.02(P均<0.01);Wistar大鼠分别为0.53±0.01、0.51±0.01、0.47±0.02 和0.40±0.02,与对照组 (0.68±0.01) 相比差异非常显著(P均<0.01).SHR组与Wistar大鼠组相比较,CFs受抑制的效应更强.结论阿伐他汀呈浓度依赖性抑制SHR的CFs增殖和胶原合成,高血压时CFs对阿伐他汀更为敏感,这对逆转高血压心室重塑有一定的价值.     

胰岛素瘤的解剖分布特点分析

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。     

Pathogenesis of carcinoma of the papilla of Vater

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.     

Demonstration of the mechanism of action of biguanides

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.     

Lack of correlation of degree of villous atrophy with severity of clinical presentation of coeliac disease

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.     

氯硝柳胺悬浮剂的毒性评价

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。     

血吸虫童虫生长发育及其机制的研究进展

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。     

124例耐多药结核分枝杆菌基因突变特征分析

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。     

Assessment of quality of life of parents of children with juvenile chronic arthritis

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     

Numerical Simulation of the Effect of Rate of Change of Glucose on Measurement Error of Continuous Glucose Monitors

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.     

治疗高血压药物的经济学评价

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。