缺氧对人胰腺癌细胞整合素α5、β1表达的影响

目的 探讨缺氧环境对人胰腺癌细胞株PANC1诱导因子-1α(hypoxia-inducible factor 1α,HIF-1α)、整合素α5(integrinα,INFα5)和整合素β1(integrinβ1,INTβ1)表达及侵袭力的影响.方法 以5%氧条件下培养PANC1,采用RT-PCR和Western blot 检测 HIF-1α、INTα5、的mRNA 和蛋白表达;采用Matrigel胶观测人胰腺癌细胞黏附侵袭能力的变化.并加入HIF-1α抑制剂YC-1缺氧培养PANC1,观察上述各指标的变化.结果 HIF-1α蛋白表达从常规培养时0.497±0.011逐渐上升到缺氧培养24h的1.455±0.133(P＜0.05),应用YC-1后蛋白表达下降到0.465±0.073(P＜0.05),而HIF-1α mRNA 表达无明显变化;INTα5蛋白从常规培养时0.964±0.032逐渐下降到缺氧培养24h的0.465±0.073(P＜0.05),应用YC-1后蛋白表达又上升到0.883±0.013(P＜0.05),INTα5mRNA的表达从0.212±0.023下降到0.018±0.002(P＜0.05),应用YC-1后再上升到0.069±0.011(P＜0.05);INTβ1的蛋白和mRNA 表达于缺氧培养及YC-1处理后均无明显变化.细胞侵袭力从常规培养时69.9±30.5逐渐上升到缺氧培养24h的105.0±14.9(P＜0.05),应用YC-1后又不降到79.7±20.9(P＜0.05).结论缺氧微环境下HIF-1α过表达可能通过下调INTα5来调控胰腺癌细胞间和细胞与基质间的黏附能力,有利于进一步侵袭转移.     

Jagged1基因沉默对人胰腺癌细胞SW1990和PANC1血管相关因子分泌及迁移能力的影响

目的 以RNA干扰技术靶向沉默人胰腺癌细胞株Jagged1基因,观察细胞VEGF、Angiopoietin2、bFGF、MMP9的分泌及细胞迁移能力的变化.方法 应用靶向Jagged1的siRNA、对照siRNA(c-siRNA)转染人胰腺癌细胞株SW1990和PANC1,实时PCR法和蛋白质印迹法检测细胞Jagged1 mRNA和蛋白的表达,ELISA法检测细胞培养上清中VEGF、angiopoietin2、bFGF、MMP9的分泌量,Transwell小室观察细胞的迁移能力.结果 SW1990和PANC1细胞均高表达Jagged1基因.15 nmol/L Jagged1 siRNA转染胰腺癌细胞72 h后,SW1990、PANC1细胞的Jagged1 mRNA表达被抑制,分别为c-siRNA组的(59.62 ±2.75)％和(76.96 ±6.16)％,Jagged1蛋白表达几乎完全被抑制.SW1990、PANC1细胞的VEGF分泌量均较c-siRNA组显著减少[(867.93±58.69) pg/ml比(1516.24±37.58)pg/ml,(951.13±120.49) pg/ml比(1413.68±33.56) pg/ml,P＜0.05],但angiopoietin2、bFGF、MMP9蛋白分泌无明显变化.另外,Jagged1 siRNA转染后,SW1990细胞VEGF mRNA表达水平为c-siRNA组的(52.26 ±4.85)％ (P＜ 0.05);PANCI细胞为c-siRNA组的(59.75±4.91)％(P＜0.05).转染后的SW1990和PANC1细胞的穿膜细胞数分别为(65.25±5.56)、(57.50±8.58)个,较c-siRNA组的( 122.25±11.09)、(112.00±12.52)个显著减少(P＜0.05).结论 人胰腺癌细胞高表达Jagged1,沉默Jagged1基因可明显抑制人胰腺癌细胞VEGF的产生和分泌,并且可降低癌细胞的体外迁移能力.     

胰岛素通过激活P13K/mTOR通路诱导人肾小系膜细胞血管内皮细胞生长因子转录

目的 探讨胰岛素诱导人肾小球系膜细胞(HMC)血管内皮细胞生长因子(VEGF)基因转录机制. 方法 (1)用VEGF报告质粒或低氧诱导因子1(HIF-1)结合位点畸变的VEGF mut报告质粒转染HMC,荧光素酶分析法检测其转录活性;(2)应用Real-time PCR、Western blot法分别检测HIF-1α mRNA和蛋白表达. 结果 (1)胰岛素呈剂量依赖性增加VEGF基因转录,在100nmol/L时达高峰,为未刺激组的2.14±0.17倍(P<0.01),但对转染VEGF mut报告质粒的HMC VEGF基因转录无影响;(2)Ly294002和雷帕霉素均可抑制胰岛素诱导的VEGF基因转录(P<0.01);(3)胰岛素呈时间依赖性上调HIF-1α蛋白表达,4h达高峰,为对照组的2.35±0.35倍(P<0.01),但对其mRNA表达无影响. 结论 胰岛素通过激活P13K/mTOR通路和上调HIF-1α蛋白表达诱导HMC VEGF基因转录.     

Dysadherin基因沉默对胰腺癌细胞侵袭移行能力的影响

目的 探讨靶向封闭dysadherin基因对胰腺癌细胞PANC1、BxPC3体外侵袭移行能力的影响.方法 应用脂质体转染方法将小分子RNA(siRNA)转染细胞.实验分为dysadherin-siRNA转染(dysa)组、阴性对照siRNA转染(HK)组、脂质体对照(对照)组、.采用RT-PCR、免疫组化方法检测转染细胞的dysadherin mRNA及蛋白表达;采用Transwell侵袭小室检测转染细胞体外侵袭移行能力.结果 转染dysadherin-siRNA(5 nmol/L)的PANC1和BxPC3细胞的dysadherin mRNA表达较HK组细胞分别下降95.4%、52.1%(P＜0.05);dysadherin蛋白表达亦分别降低91.2%、83.6%(P＜0.01).PANC1细胞的对照组、HK组和dysa组穿膜细胞数分别为163.2±15.5、154.4±17.3和53.6±7.9;BxPC3细胞的对照组、HK组和dysa组穿膜细胞数分别为30.7±3.2、27.5±2.8和4.7±2.4.dysa组显著低于HK组和对照组(P值均＜0.01).结论 应用RNA干扰技术沉默人胰腺癌细胞株PANC1、BxPC3的dysadherin基因可使细胞的侵袭移行能力下降.     

缺氧对人胰腺癌细胞整合素α5、β1表达的影响

目的探讨缺氧环境对人胰腺癌细胞株PANC1诱导因子-1α(hypoxia-inducible factor 1α,HIF-1α)、整合素α5(integrinα,INFα5)和整合素β_1(integrinβ,INTβ_1)表达及侵袭力的影响。方法以5%氧条件下培养PANC1,采用RT-PCR和Western blot检测HIF-1α、INTα_s、INTβ_1的mRNA和蛋白表达;采用Matrigel胶观测人胰腺癌细胞黏附侵袭能力的变化。并加入HIF-1α抑制剂YC-1缺氧培养PANC1,观察上述各指标的变化。结果HIF-1α蛋白表达从常规培养时0.497±0.011逐渐上升到缺氧培养24h的1.455±0.133(P<0.05),应用YC-1后蛋白表达下降到0.465±0.073(P<0.05),而HIF-1αmRNA表达无明显变化;INT_(α5)蛋白从常规培养时0.964±0.032逐渐下降到缺氧培养24h的0.465±0.073(P<0.05),应用YC-1后蛋白表达又上升到0.883±0.013(P<0.05).INT_(α5)mRNA的表达从0.212±0.023下降到0.018±0.002(P<0.05),应用YC-1后再上升到0.069±0.011(P<0.05);INTβ1的蛋白和mRNA表达于缺氧培养及YC-1处理后均无明显变化。细胞侵袭力从常规培养时69.9±30.5逐渐上升到缺氧培养24h的105.0±14.9(P<0.05),应用YC-1后又下降到79.7±20.9(P<0.05)。结论缺氧微环境下HIF-1α过表达可能通过下调INT_(α5)来调控胰腺癌细胞间和细胞与基质间的黏附能力,有利于进一步侵袭转移。     

整合素β1基因沉默对胰腺癌细胞PANC1体外侵袭能力的影响及机制研究

目的 应用短发夹RNA(shRNA)沉默人胰腺癌细胞株PANC1的整合素α1(integrinβ1)基因表达,观察其对PNAC1细胞体外侵袭能力的影响,探讨其机制.方法 构建靶向integrinβ1基因的shRNA真核表达质粒integrinβ1-shRNA及对照真核表达质粒c-shRNA,转染人胰腺癌PANC1细胞,以未转染质粒的细胞作为对照组.应用实时荧光定量PCR和蛋白质印迹法检测integrinβ1、MMP-2、MMP-9 mRNA和蛋白的表达水平,应用Transwell侵袭小室检测细胞体外侵袭能力.结果 integrinβ1-shRNA 组、c-shRNA组和对照组细胞integrinβ1 mRNA表达量分别为0.0029±0.0004、0.0131±0.0009、0.0138±0.0005;integrinβ1蛋白表达量为0.0159±0.0062、0.3215 ±0.0126、0.3107±0.0094.integrinβ1-shRNA 组integrinβ1 mRNA和蛋白表达抑制率分别为(78.6±7.2)％和(92.9±3.2)％(P＜0.01).而c-shRNA 组与对照组差异无统计学意义(P =0.2999).integrinβ1-shRNA组穿膜细胞数由(52±5)个降低至(21 ±4)个(P＜0.01);MMP-2和MMP-9mRNA表达分别从0.592±0.073和0.847±0.069降低到0.102±0.034和0.273±0.071;MMP-2和MMP-9蛋白表达分别从0.225±0.046和0.416±0.081降低到0.059±0.013和0.106±0.022(P值均＜0.05).结论 重组质粒integrinβ1-shRNA能有效地抑制PANC1细胞integrinβ1基因的表达,并可能通过下调MMP-2和MMP-9基因表达而抑制其体外侵袭能力.     

胰岛素通过激活P13K／mTOR通路诱导人肾小球系膜细胞血管内皮细胞生长因子转录

目的探讨胰岛素诱导人肾小球系膜细胞（HMC）血管内皮细胞生长因子（VEGF）基因转录机制。方法（1）用VEGF报告质粒或低氧诱导因子1（HIF-1）结合位点畸变的VEGF mut报告质粒转染HMC,荧光素酶分析法检测其转录活性;（2）应用Real—time PCR、Western blot法分别检测HIF-1α mRNA和蛋白表达。结果（1）胰岛素呈剂量依赖性增加VEGF基因转录,在100nmol／L时达高峰,为未刺激组的2．14±0．17倍（P〈0．01）,但对转染VEGF mut报告质粒的HMC VEGF基因转录无影响;（2）Ly294002和雷帕霉素均可抑制胰岛素诱导的VEGF基因转录（P〈0．01）;（3）胰岛素呈时间依赖性上凋HIF-1α蛋白表达,4h达高峰,为对照组的2．35±0．35倍（P〈0．01）,但对其mRNA表达无影响。结论胰岛素通过激活P13K／mTOR通路和上调HIF-1α蛋白表达诱导HMC VEGF基因转录。     

缺氧对胰腺癌PANC1细胞增殖、凋亡及迁移的影响

目的 探讨氯化钴( CoCl2)模拟缺氧对人胰腺癌细胞株PANC1增殖、凋亡和迁移的影响.方法 分别用终浓度为0(对照)、100、200、400、800 μmol/L CoCl2处理PANC1细胞24h,采用实时定量PCR、蛋白质印迹法分别检测细胞缺氧诱导因子(HIF)-1α、血管内皮生长因子(VEGF) mRNA及蛋白的表达,采用CCK-8法检测细胞增殖,流式细胞术检测细胞凋亡,细胞划痕试验检测细胞迁移能力.结果 对照组及100、200、400、800 μmol/L CoCl2处理组HIF-1α mRNA表达量分别为1、1.08±0.12、1.12±0.09、1.04±0.11、0.66±0.07;VEGF mRNA表达量分别为1、2.69±0.35、4.81±0.54、2.19 ±0.21、0.79±0.08;HIF-1α蛋白表达量为0.23±0.03、0.36±0.04、1.15±0.11、1.08±0.09、0.44±0.04;VEGF蛋白表达量为0.14±0.02、0.12±0.01、0.95±0.09、0.87±0.09、0.55±0.06;细胞存活率分别为100％、(98.43±2.88)％、(76.15±0.70)％、(53.87±0.77)％、(35.23±0.67)％;细胞凋亡率分别为(5.2±1.12)％、(5.74±1.07)％、(6.82±1.85)％、(12.09±3.53)％、(31.88±6.95)％;细胞爬行距离分别为(43.24±3.67)％、(59.46±5.39)％、(80.56±8.05)％、(63.89±5.96)％、(9.09±1.59)％.与对照组相比较,处理组细胞VEGF mRNA、VEGF及HIF-1α蛋白表达、细胞爬行距离均呈先上升后下降的趋势(P＜0.05),HIF-1αmRNA表达、细胞增殖率呈剂量依赖性降低,细胞凋亡率呈剂量依赖性升高.结论 CoCl2达到一定浓度时可显著抑制PANC1细胞增殖,促进细胞凋亡;CoCl2对PANC1细胞迁移效应的双向作用与高浓度CoCl2对细胞直接损伤有关.     

HIF-1对乏氧人肺腺癌 A549细胞侵袭、迁徙能力的影响及其机制

目的：探索低氧诱导因子-1(HIF-1)对乏氧人肺腺癌 A549细胞侵袭及迁徙能力的影响及可能机制。方法采用氯化钴建立人肺腺癌 A549细胞体外化学乏氧模型。给予 HIF-1α特异性抑制剂YC-1抑制 A549细胞 HIF-1α的表达;通过 Western blot、免疫细胞化学、real time-PCR 检测 HIF-1α、S100A4蛋白及 mRNA 的表达;Transwell 小室模型检测 A549细胞 侵 袭 及 迁 徙 能 力。结果乏氧组A549细胞 HIF-1α、S100A4表达较常氧组增加,侵袭及迁徙能力较常氧组增强。YC-1干扰 HIF-1α表达后,YC-1组 A549细胞侵袭及迁徙能力减弱,S100A4蛋白及 mRNA 表达均降低。结论 HIF-1可能通过上调 S100A4的表达促进乏氧人肺腺癌 A549细胞侵袭及迁徙的能力。     

胃腺癌中缺氧诱导因子-1αmRNA表达和血管生成的关系

目的:探讨胃腺癌中缺氧诱导因子-1α(HIF-1α)mRNA、血管内皮生长因子(VEGF)和MVD的表达,探讨其间的相互关系及临床意义. 方法:应用原位杂交和免疫组化方法检测HIF-1αmRNA、VEGF蛋白的表达,用CD-34单克隆抗体标记肿瘤微血管密度. 结果:胃腺癌组HIF-1αmRNA、VEGF的阳性表达率分别为76.7%和66.7%,明显高于正常对照组的20%和0%,胃腺癌组的MVD为34±10,高于正常对照组的15±5,(P＜0.01),.MVD表达与肿瘤的分化情况,即病理分型密切相关,(P＜0.01);而与TNM分期、淋巴结转移和远处转移情况无明显相关性.VEGF阳性表达率与TNM分期表现出一定的相关性,而与病理分型无关,发生远处转移者的VEGF阳性表达率81.9%,高于无远处转移者52.6%(P＜0.05).HIF-1mRNA表达与MVD呈正相关(r=0.37,P＜0.05);与VEGF表达也表现出正相关性(r=0.42,P＜0.05);而VEGF表达与MVD并无相关(r=0.19,P＞0.05). 结论:胃腺癌HIF-1αHIF-1αmRNA过度表达与肿瘤中血管生成密切相关,HIF-1α可以通过诱导VEGF生成而刺激肿瘤血管生成,但这一路径并不是HIF-1α影响肿瘤的血管生成的唯一路径.     

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。     

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。     

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。     

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.