维生素D受体基因多态性与Graves病易感性的关系

目的探讨维生素D受体(VDR)基因Apa I(rs7975232)单核苷酸多态性与汉族人群Graves病的关系。方法选取Graves病患者260例和对照组221例,收集相关资料,检测甲状腺相关激素及25羟维生素D〔25(OH)D〕水平。应用聚合酶链式反应-限制性长度多态性(PCRRFLP)对样本基因分型。分析基因多态性与Graves病、25(OH)D与促甲状腺激素受体抗体(TRAb)滴度之间的相关性,25(OH)D及TRAb水平在不同基因型者之间的差异。结果 (1)Graves病组C等位基因及CC基因型分布频率高于对照组(C vs.A:57.1%vs.47.3%,χ2=9.260,P=0.002;CC vs.AA:χ2=7.912,P=0.005);相对于基因型AA者,CC基因型增加Graves病发病风险(OR=2.003,95%CI:1.235~3.246)。(2)Graves病初发组中,血清25(OH)D水平较对照组显著降低〔(14.74±3.10)vs(20.98±2.82)ng/ml,F=50.9,P0.001〕;25(OH)D与TRAb水平呈负相关(r=-0.264,P=0.035);AA基因型者25(OH)D水平较CC+AC基因型者高〔(16.12±3.28)vs(14.16±2.86)ng/ml,F=2.975,P=0.039〕,而TRAb值较低〔(11.65±3.90)vs(18.12±8.63)IU/L,F=3.244,P=0.028〕。结论 VDR基因Apa I(rs7975232)多态性可能与汉族人群Graves病及其25(OH)D、TRAb水平相关;Graves病初发组患者伴随低25(OH)D,且与TRAb负相关。     

G蛋白β3亚单位C825T等位基因多态性与原发性高血压的关系

目的 探讨温州地区汉族人群G蛋白β3亚单位(GNB3)C825T等位基因多态性与原发性高血压的相关性.方法 原发性高血压患者109例,正常对照组378例,聚合酶链反应(PCR)/酶解-琼脂糖凝胶电泳检测基因型.结果 (1)温州地区汉族人群GNB3 825T等位基因频率为43.5%,与其他人种的该基因频率显著不同.(2)原发性高血压组的TT基因型携带率明显升高(P＜0.01),TT基因型携带者与CT型携带者比较,其致高血压的比数比(OR值)为2.5(P＜0.01);TT型与CC型比,其OR值为2.4(P＜0.01);等位基因T与C比较,致高血压的OR值为1.5(P＜0.05).(3)GNB3不同基因型间的血压水平比较,收缩压CT和TT携带者与CC携带者比较均增高(P＜0.05和P＜0.01),TT携带者与CT携带者比较亦有升高(P＜0.01),舒张压TT携带者比CC携带者增高(P＜0.05),而CT携带者与CC携带者比较差异无显著性(P＞0.05),TT携带者与CT携带者比较,收缩压和舒张压均增高(P＜0.01和P＜0.05).结论 GNB3 825T基因型可作为早期预测原发性高血压的遗传学指标之一.     

连接蛋白37基因C1019T多态性与缺血性卒中及其转归的相关性

目的 探讨连接蛋白37(connexin37,Cx37)基因C1019T多态性与缺血性卒中及其转归的关系.方法 采用限制性片段长度多态性分析技术检测缺血性卒中组和对照组Cx37基因C1019T多态性的分布,采用改良Rankin量表(modified Rankin Scale,mRS)评价发病后3个月时神经功能转归.结果 纳入急性缺血性卒中患者232例,其中转归良好(mRS评分＜3分)210例,转归不良(mRS评分≥3分)22例;对照组235例.缺血性卒中组TT基因型(12.93％对6.39％;x2=10.087,P=0.006)和T等位基因(31.25％对21.49％;x2 =11.466,P=0.001)频率显著高于对照组.多变量logistic回归分析显示,TT基因型[优势比(odds ratio,OR)5.794,95％可信区间(confidence interval,CI)1.405～23.894;P=0.015]和T等位基因(OR 131.016,95％ CI 6.943～2472.477;P =0.001)可显著增高缺血性卒中的发病风险.单因素分析显示,TT基因型(OR 0.650,95％ CI 0.144～2.934;P=0.575)、CT基因型(OR 0.622,95％ CI 0.234～1.655;P=0.342)、CC基因型(OR 0.654,95％ CI0.268～1.595;P=0.350)与缺血性卒中转归均无显著相关性.结论 Cx37 1019TT基因型和T等位基因可增高缺血性卒中风险,T等位基因是缺血性卒中的遗传易感因素之一,但其基因多态性与缺血性卒中发病3个月时的转归无关.     

间隙性连接蛋白37基因1019C/T多态性与原发性高血压的关系

目的 研究无锡地区人群中间隙性连接蛋白37 （connexin 37,CX 37）基因1019C/T多态性与原发性高血压的相关性.方法 入选在无锡市人民医院初次诊断为原发性高血压的患者1 126例,874名健康体检者作为正常对照组,均采用基因测序技术对CX37基因1019多态性位点基因型进行检测,比较两组人群中基因型及等位基因分布差异.结果 （1）两组人群中均存在CX 37基因1019C/T多态性,基因型分布均符合Hardy-Weinberg遗传平衡定律.（2）原发性高血压组与正常对照组相比,C等位基因分布频率升高（57.37％vs.42.05％,P＜0.01）.C等位基因携带者（CC＋TC）在原发性高血压组高于对照组,差异有统计学意义（80.46％ vs.66.70％,P＜0.01）.与Tr纯合子相比,（CC＋TC）基因型原发性高血压患病风险增加（OR=2.06,95％ CI：1.68～2.52）.对性别进行亚组分析显示：无论男性还是女性人群中原发性高血压组C等位基因携带者频率均显著高于正常对照组（男性：79.19％vs.69.05％,P＜0.01;女性：81.75％ vs.64.40％,P＜0.01）,C等位基因携带者原发性高血压患病风险明显高于TT型（男性：OR=1.71,95％CI：1.28～2.27;女性：OR=2.48,95％ CI：1.85～3.31）.结论 CX37 C等位基因可能与老年原发性高血压相关.     

PSCA rs2294008位点多态性与胃癌癌前病变关系的Meta分析

目的系统评价前列腺干细胞抗原(PSCA)rs2294008位点多态性与胃癌癌前病变是否存在相关性。方法应用计算机检索电子数据库Pub Med、Sino Med、CNKI、万方、VIP,按纳入标准搜索含有研究PSCA rs2294008多态性与胃癌癌前病变相关性的文章,并对所纳入文献进行Meta分析。结果共5篇文章纳入研究,病例组2 310例,对照组3 240例,研究表明,PSCA ra2294008等位基因模型、加性模型、共显性模型、显性模型与胃癌癌前病变的易感性有关,差异有统计学意义(T vs C:OR=1.18,95%CI:1.09~1.28,P0.0001;TT vs CC:OR=1.46,95%CI:1.08~1.97,P=0.01;CT vs CC:OR=1.25,95%CI:1.09~1.42,P=0.0009;CT+TT vs CC:OR=1.31,95%CI:1.16~1.49,P0.0001),隐性模型与胃癌癌前病变的易感性有关,但差异无统计学意义(TT vs CT+CC:OR=1.24,95%CI:0.93~1.66,P=0.15)。PSCA突变等位基因T增加了萎缩性胃炎的易感性,差异有统计学意义(T vs C:OR=1.24,95%CI:1.12~1.38,I2=24,P0.0001;TT vs CC:OR=1.60,95%CI:1.28~2.01,I2=3,P0.0001;CT vs CC:OR=1.42,95%CI:1.17~1.72,I~2=0,P=0.0004;CT+TT vs CC:OR=1.47,95%CI:1.22~1.77,I~2=0,P0.0001;TT vs CC:OR=1.24,95%CI:1.04~1.47,I2=47,P=0.02)。结论 PSCA rs2294008位点多态性与胃癌癌前病变有相关性。     

白细胞介素13基因-1112C/T多态性与支气管哮喘患者发病及血浆总IgE水平的相关性

目的探讨白细胞介素13(IL13)基因启动子区-1112C/T多态性与支气管哮喘(简称哮喘)的相关性及对血浆总IgE水平的影响。方法将哮喘患者(100例)和健康人(100名)被分为哮喘组和对照组,用聚合酶链反应限制性片段长度多态性(PCRRFLP)方法检测哮喘组与对照组-1112位点多态性,用酶联免疫吸附法(ELISA)测定血浆总IgE水平。结果-1112位点等位基因C、T频率在两组间分布的差异具有显著性(χ2=901,P<001),等位基因T与哮喘关联[OR(T/C)=203,95%CI=127～323,P<001]。两组基因型(TT、CT、CC)频率的分布比较差异有显著性(χ2=719,P<005),其优势比OR(TT/CC)=299,95%CI=106～841(P<005);OR(CT/CC)=204,95%CI=109～381(P<005);OR(TT/CT)=146,95%CI=049～437(P>005);在哮喘组CC、CT及TT基因型患者的血浆总IgE水平分别为(204±89)kU/L、(320±108)kU/L、(376±147)kU/L,而在对照组CC、CT及TT基因型患者的血浆总IgE水平分别为(96±34)kU/L、(122±42)kU/L、(150±36)kU/L。同组内T等位基因携带者血浆总IgE水平高于非携带者;同一基因型中哮喘组总IgE水平高于对照组。结论IL13基因-1112位点多态性是影响哮喘的重要候选基因,T等位基因与哮喘关联,并可能通过增强IL13基因的表达影响血浆总IgE水平。     

高血压病患者G蛋白β3基因C825T和eNOS基因G894T多态性研究

目的　观察高血压病 (EH)患者G蛋白 β3亚单位基因 (GNB3)C82 5T多态性和内皮一氧化氮合酶 (eNOS)基因G894T多态性 ,探讨EH发生的遗传学机制。方法　EH患者 112例 ,对照组 112例。取血标本提取DNA ,用PCR方法扩增目的基因 ,用限制性内切酶 (BanⅡ、BseDI)酶切PCR产物用于基因分型。结果　EH患者GNB3C82 5T基因型分布 (基因型频率CC =0 34,CT =0 5 3 ,TT =0 13)与对照组有显著性差异 (基因型频率CC =0 5 9,CT =0 36 ,TT =0 0 5。χ2 =6 9,P <0 0 5 ) ;82 5T等位基因携带者与CC纯合子比较有较高的患EH的危险 (OR =2 2 ,95 %CI1 1～ 4 6 )。eNOS各基因型在EH的分布与对照组无显著性差异。Logistic回归分析显示 ,GNB3 82 5T等位基因与EH关联最密切。结论GNB3基因C82 5T多态性的 82 5T等位基因是EH发病的遗传危险因子。eNOS基因G894T多态性在EH发病中不起直接重要作用。     

NQO1单核苷酸多态性和环境因素的交互作用与肝细胞癌的关联研究

目的 研究NQO1基因多态性和环境因素的交互作用与肝细胞癌易感性的关系. 方法 采用以医院为基础的病例对照研究方法,运用TaqMan MGB荧光定量实时PCR分析方法对病例组400例肝细胞癌患者和对照组400例非肿瘤患者进行NQO1基因C609T位点的基因型分析.以非条件logistic回归模型分析比较各基因型在两组中分布频率的差异,以及基因多态性和环境因素的交互作用.结果 NQO1基因C609T位点CC、CT和TT各基因型频率分别为23.75％、50.25％和28.00％,对照组中3种基因型频率分别为37.55％、43.75％和18.25％,差异有统计学意义(P＜0.05).与CC基因型相比,CT或者TT基因型的个体罹患HCC的风险OR分别为2.106(95％CI:1.137～3.110)和2.564(95％CI:1.357～4.744).T等位基因携带者患肝细胞癌的危险性是C等位基因携带者的1.86倍(OR=1.86,95％ CI:1.235 ～ 2.980).交互作用分析结果表明NQO1基因多态性与肿瘤家族史、HBsAg阳性之间在肝细胞癌发生中存在交互作用,交互作用的OR值分别为2.431、8.359. 结论 NQO1C609T基因型可能是广西南部地区人群患肝细胞癌的危险因素之一,NQO1基因多态性与肿瘤家族史、HBsAg阳性之间在肝细胞癌发生中存在交互作用,能增加罹患肝细胞癌的风险.     

CD40基因单核苷酸多态性及单倍型与缺血性脑卒中的相关性研究

目的研究CD40基因单核苷酸多态性及其单倍型与缺血性脑卒中易感性之间的关系;同时分析CD40基因型及血清水平与缺血性脑卒中的相关性。方法选择缺血性脑卒中患者202例(脑卒中组),健康体检者199例(对照组),应用单碱基延伸的PCR技术和DNA测序法对CD40基因rs1883832C/T、rs1569723A/C和rs4810485G/T单核苷酸多态性进行基因分型,同时采用ELISA法检测血清CD40水平。结果脑卒中组与对照组CD40基因rs1883832C/T位点基因型和等位基因频率比较,差异有统计学意义(P<0.01)。等位基因频率的相对风险分析发现,rs1883832T等位基因携带者患缺血性脑卒中的风险是C等位基因的1.557倍(P=0.002);携带rs1883832T等位基因的缺血性脑卒中患者血清CD40水平显著高于不携带者(P<0.05)。联合基因型分析发现,脑卒中组T-C-T单倍型携带者较对照组明显增加了发病风险(P=0.033)。结论 CD40基因rs1883832C/T多态性和T-C-T单倍型与缺血性脑卒中的发病具有相关性,其中T等位基因可能是缺血性脑卒中的遗传易感基因,携带T等位基因的个体可能通过促进CD40的高度表达进而增加了缺血性脑卒中的发病风险。     

半乳糖凝集素-2基因变异与急性冠状动脉综合征风险关联研究

目的:研究半乳糖凝集素-2(LGALS2)基因变异与急性冠状动脉综合征(ACS)惟患风险之间的关系.方法:采用聚合酶链反应-限制性片段长度多态性法对248例ACS组患者、212例稳定性心绞痛组患者和138例对照组患者检测LGALS2基因C3279T位点基因型、基因型频率,等位基因、等位基因频率,用冠状动脉造影测定病变血管支数和狭窄程度积分,用酶联免疫吸附法测试血浆淋巴毒素α和血管细胞黏附分子-1水平;用散射比浊法测试血浆C反应蛋白水平;探索基因型变异与ACS风险、病变血管支数、狭窄程度积分和3个细胞因子水平之间的关系.结果:ACS组与对照组比TT基因型频率和T等位基因频率显著减低(P＜0.01和P＜0.001),差异有统计学意义;稳定性心绞痛组与对照组比TT基因型频率和T等位基因频率差异无统计学意义(P＞0.05).CT TT基因型发生ACS的危险性与CC基因型发生ACS的危险性比(OR=0.73,P＜0.01)、T等位基因发生ACS的危险性与C等位基因发生ACS的危险性比(OR=0.67,P＜0.001)差异均有统计学意义;但CT TT基因型发生稳定性心绞痛的危险性与CC基因型发生稳定性心绞痛的危险性比(OR=0.84,P＞0.05)、T等位基因发生稳定性心绞痛的危险性与C等位基因发生稳定性心绞痛的危险性比(OR=0.84,P＞0.05)差异均无统计学意义.基因型与冠状动脉病变程度:TT基因型与CC基因型比血管病变支数频率和狭窄程度积分均显著降低(P＜0.05和P＜0.001).基因型变异与炎性细胞因子:TT基因型与CC基因型比血浆淋巴毒素α、C反应蛋白、血管黏附分子-1水平均显著降低(均P＜0.001).结论:LGALS2基因C3279T位点变异对ACS易患风险、血管病变程度和炎症级联反应起保护作用.     

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.     

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。     

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。     

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.     

Angiographic diagnosis of the degree of serosal invasion of carcinoma of the colon

Angiography using Prostaglandin El^® was performed on 38 patients with carcinoma of the colon in order to diagnose the degree of serosal cancer invasion. The findings at angiography were classified into four groups:1) AG-S3, abnormal change (irregularity and/or encasement) up to marginal vessels; 2) AG-S2, abnormality up to vasa recta; 3) AG-S1, abnormality of penetrating branches of vasa recta within the wall of the colon; and 4) AG-S0, no distinct findings of abovementioned vessels. These angiographic findings were compared with both macroscopic and microscopic serosal cancer invasion. Angiographic diagnosis is in accord with the macroscopic findings in 84.2 percent of cases. Angiographic diagnosis is in accord with the microscopic findings in 32.4 percent of cases. Macroscopic findings confirm the angiographic diagnosis precisely but the conflict with microscopic findings should not be overlooked. This may be the result of inflammatory change, adhesion, and fibrosis around carcinoma of the colon.