非诺贝特对过氧化物酶体增殖物激活受体α和单核细胞趋化蛋白-1的影响

目的观察非诺贝特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、单核细胞过氧化物酶体增殖物激活受体(PPARα)和单核细胞趋化蛋白-1(MCP-1)的影响。方法体外培养HUVEC株,第3~5代用于实验。实验分3组:1空白对照组;2ox-LDL组(100 mg/L);3非诺贝特组:先将非诺贝特10、50、100μmol/L分别作用于内皮细胞24 h,然后加ox-LDL(100 mg/L)作用于细胞24 h。采用细胞酶联免疫吸附法分析检测细胞培养上清液PPARα、MCP-1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促进内皮细胞增殖(PO.01),非诺贝特呈剂量依赖性地抑制ox-LDL诱导的内皮细胞增殖(P0.01)。100 mg/L ox-LDL促进MCP-1分泌。10、50、100μmol/L非诺贝特能明显促进ox-LDL诱导的HUVEC分泌PPARα(P0.01),促进效应呈浓度依赖性。10、50、100μmol/L非诺贝特能明显抑制ox-LDL诱导的HUVEC分泌MCP-1(P0.01),抑制效应呈浓度依赖性。结论非诺贝特呈剂量依赖性促进ox-LDL诱导的人HUVEC分泌PPARα,抑制人HUVEC分泌MCP-1,抑制内皮细胞增殖,保护内皮功能,从而发挥贝特类调脂外抗动脉粥样硬化作用。     

阿托伐他汀对ox-LDL诱导的炎症反应的影响及其机制探讨

目的 探讨阿托伐他汀对氧化低密度脂蛋白（ox-LDL）诱导的内皮细胞炎症反应的影响.方法 将单核细胞THP1细胞随机分4组,分别为：空白对照组、ox-LDL组、阿托伐他汀组、阿托伐他汀＋ox-LDL组.作用24h后收集细胞.应用ELISA法检测各组THP1细胞上清液中的炎症因子TNF-α、IL-1β和IL-6水平.结果 与ox-LDL组相比,阿托伐汀组和阿长伐他汀fox-LDL组THP细胞分泌的TNF-α、IL-1β和IL-6明显降低（P均＜0.05）.结论 阿托伐他汀可以降低ox-LDL诱导的炎症反应.     

普罗布考抑制氧化低密度脂蛋白诱导人脐静脉内皮细胞Fractalkine的表达

目的:探讨氧化低密度脂蛋白(ox-LDL)诱导人脐静脉内皮细胞(HUVEC)产生趋化因子Fractalkine及普罗布考的抑制作用.方法:用不同浓度的ox-LDL刺激HUVEC及用不同浓度普罗布考和PDTC预处理细胞后再用ox-LDL刺激,半定量RT-PCR方法检测Fractalkine和NF-κB p65的mRNA的表达.结果:未用ox-LDL刺激的HUVEC不表达Fractalkine,分别用25、50、100 mg/L浓度的ox-LDL刺激后,Fractalkine mRNA的表达呈浓度依赖性增加,与空白对照组比较分别增加384.58%(P＜0.01)、484.09%(P＜0.01)、558.26%(P＜0.01),同时NF-κB p65 mRNA的表达分别增加15.71%(P＞0.05),41.73%(P＜0.01),66.72%(P＜0.01).40 μmol/L PDTC预处理后,再用50 mg/L ox-LDL刺激HUVEC,NF-κB p65 mRNA的表达下降25.61%(P＜0.01),分别用20、40、80 μmol/L的普罗布考干预后,NF-κB p65 mRNA的表达分别下调15.52%(P＜0.05)、24.92%(P＜0.01)、34.93%(P＜0.01);同时,Fractalkine mRNA的表达则分别下调32.22%(P＜0.01)、10.07%(P＞0.05)、20.59%(P＜0.01)、33.60%(P＜0.01).结论:ox-LDL可以通过NF-κB p65诱导HUVEC表达Fractalkine,而普罗布考则可以抑制Fractalkine的表达,这种作用可能与抑制NF-κB p65有关.     

Ang-Ⅱ对血管内皮细胞线粒体膜电位的影响及阿托伐他汀的保护作用

目的:观察血管紧张素-Ⅱ(Ang-Ⅱ)对血管内皮细胞线粒体膜电位的影响及阿托伐他汀的保护作用.方法:将血管内皮细胞分为:空白对照组(仅给予细胞培养液)、Ang-Ⅱ组(细胞培养液中加入Ang-Ⅱ,使其终浓度为10-7mol/L)、Ang-Ⅱ加小剂量阿托伐他汀组(在单纯Ang-Ⅱ组的基础上加入阿托伐他汀,使阿托伐他汀的终浓度为0.1 μmol/L)、Ang-Ⅱ加大剂量阿托伐他汀组(在单纯Ang-Ⅱ组的基础上加入阿托伐他汀,使阿托伐他汀的终浓度为1 μmol/L).用激光共聚焦显微镜测量各组细胞的线粒体膜电位水平.结果:①Ang-Ⅱ组的线粒体膜电位显著低于空白对照组(P<0.01);②Ang-Ⅱ加阿托伐他汀组的线粒体膜电位显著高于Ang-Ⅱ组(P<0.01).③Ang-Ⅱ加大剂量阿托伐他汀组的线粒体膜电位水平高于Ang-Ⅱ加小剂量阿托伐他汀组(P<0.05).结论:Ang-Ⅱ可引起血管内皮细胞线粒体膜电位的显著降低,而阿托伐他汀可呈剂量依赖性的逆转Ang-Ⅱ的这一作用.     

瑞舒伐他汀对ox-LDL诱导的人单核巨噬细胞MMP-9 mRNA和蛋白表达的影响

目的 探讨瑞舒伐他汀对ox-LDL诱导的健康人单核巨噬细胞基质金属蛋白酶-9（MMP-9）mRNA及蛋白表达的影响.方法 体外密度梯度离心法分离并培养单核巨噬细胞并传至2～4代用于实验.单核巨噬细胞培养24 h作为空白对照组,ox-LDL 100 mg/ml培养24 h作为ox-LDL对照组,实验组分别用ox-LDL 100 mg/ml培养2 h后,各加入不同剂量瑞舒伐他汀（0.01、0.1、1.0、10.0 μmol/L）共同作用24 h.分别提取各组细胞RNA,用半定量逆转录聚合酶链式反应法（RT-PCR）测定MMP-9 mRNA表达,用ELISA法测定MMP-9的蛋白含量.结果 单核巨噬细胞经100 mg/ml ox-LDL诱导后,与空白对照组比较MMP-9mRNA和蛋白表达显著增加;ox-LDL诱导后,不同剂量瑞舒伐他汀组与ox-LDL对照组比较MMP-9 mRNA和蛋白表达显著降低,并呈剂量-效应关系,P＜0.05;与空白对照组比较,瑞舒伐他汀10.0μmol/L组MMP-9蛋白表达无明显变化,差异无统计学意义（P＞0.05）.结论 外周血单核巨噬细胞在ox-LDL诱导后,MMP-9mRNA和蛋白含量明显增加.瑞舒伐他汀呈剂量依赖性,可能通过ox-LDL途径来下调人单核巨噬细胞MMP-9 mRNA和蛋白含量的表达,起到抗炎和稳定斑块的作用.     

阿托伐他汀对氧化低密度脂蛋白诱导人内皮细胞环氧化酶-2表达的影响

目的探讨阿托伐他汀对氧化低密度脂蛋白（ox-LDL）干预后人内皮细胞环氧化酶-2（COX-2）表达的影响。方法体外培养人脐静脉内皮细胞,待细胞生长到融合状态时加入ox-LDL,对照组不加任何干预,作用24 h后,分别加入不同浓度的阿托伐他汀（1、10及30μmol/L）继续培养24 h。采用逆转录聚合酶链式反应技术分别测定各组COX-2 mRNA的表达。结果Ox-LDL可诱导COX-2 mRNA的表达;不同浓度的阿托伐他汀可抑制ox-LDL诱导的COX-2 mRNA的表达,并呈浓度依赖性（P〈0.05）。结论内皮细胞源性COX-2在动脉粥样硬化斑块形成中可能起着重要的促炎作用;阿托伐他汀可抑制人脐静脉内皮细胞COX-2 mRNA的表达。     

盐酸小檗碱对高糖、高脂联合诱导内皮细胞分泌TNF-α的干预作用

目的 观察盐酸小檗碱(黄连素)对高糖、高脂联合诱导下血管内皮细胞分泌肿瘤坏死因子(TNF-α)的干预作用及对内皮细胞的保护作用.方法 体外培养人脐静脉内皮细胞,建立Glu+ ox-LDL损伤HUVECs模型.实验分组:对照组:DMEM培养液+l0％胎牛血清;模型组:Glu40 mmol/L+ ox-LDL 100 mg/L;黄连素低组:Glu 40 mmol/L+ox-LDL 100 mg/L+黄连素1.25 μg/ml;黄连素中组:Glu 40 mmol/L+ ox-LDL 100 mg/L+黄连素2.5 μg/ml;黄连素高组:Glu 40 mmol/L+ ox-LDL 100 mg/L+黄连素5μg/ml.检测细胞培养液中的内皮素(ET-1)、一氧化氮(NO)和TNF-α水平.结果 细胞增殖率:Glu 40 mmol/L+ ox-LDL 100 mg/L(模型组)培养HUVECs 24 h,与对照组比较细胞存活率降低(P＜0.01),说明造模成功,同时应用1.25 ～5.0 μg/ml黄连素治疗,细胞存活率明显提高(P＜0.01).NO:模型组NO水平显著低于对照组(P＜0.01),黄连素处理组NO水平显著高于模型组,以5μg/ml剂量组作用最显著(P＜0.01).ET-1:模型组ET-1比对照组显著增高(P＜0.01),黄连素各治疗组比模型组明显降低(P＜0.01).TNF-α:对照组与模型组间内皮细胞培养液中TNF-α水平差别有统计学意义(P＜0.01),黄连素各治疗组比模型组内皮细胞培养液中TNF-α水平明显降低(P＜0.01),但仍高于对照组(P＜0.01).结论 黄连素通过调节内皮NO/ET-1平衡、抗炎作用,改善Glu、ox-LDL联合诱导的内皮细胞损伤.     

内质网应激蛋白CHOP-10在缺血缺氧诱导人主动脉内皮细胞损伤中的作用

目的探讨人主动脉内皮细胞(HAEC)在缺血缺氧刺激下内质网应激(ERS)标志蛋白C/EBP同源蛋白10(CHOP-10)的表达变化及意义,并观察阿托伐他汀对上述过程的影响。方法将传代培养的HAEC分为正常对照组、缺血缺氧组、缺血缺氧+CHOP-10基因沉默组以及缺血缺氧+阿托伐他汀组(0.l mol/L、1.0 mol/L、10.0mol/L),缺血缺氧+CHOP-10基因沉默组采用CHOP-10 shRNA下调CHOP-10的基因表达;24 h后采用RT-PCR法检测细胞中CHOP-10的基因表达,Western blot法检测CHOP-10、Caspase-3和Caspase-8的蛋白水平;采用ELISA法检测细胞培养液中白细胞介素6(IL-6)及肿瘤坏死因子α(TNF-α)的浓度;采用CCK8法测定细胞增殖活力。结果与正常对照组相比,HAEC在缺血缺氧损伤时CHOP-10表达明显升高(P0.01),细胞分泌炎性因子IL-6及TNF-α增加(P0.01),凋亡蛋白Caspase-3和Caspase-8表达增加(P0.01),细胞增殖活力明显下降(P0.01)。阿托伐他汀能呈浓度依赖性地抑制HAEC CHOP-10表达,而缺血缺氧+CHOP-10基因沉默组或缺血缺氧+阿托伐他汀组,炎性介质IL-6、TNF-α的分泌也相应减少,细胞凋亡下降,增殖活力明显增加(P0.01)。结论缺血缺氧损伤可引起血管内皮细胞发生ERS及炎症反应,导致细胞增殖活力下降,凋亡增加,CHOP-10基因沉默或应用阿托伐他汀干预可减轻缺血缺氧时ERS及炎症反应而对血管内皮细胞产生保护作用。     

不同剂量阿托伐他汀对心房颤动患者hs-CRP、NO、IL-6、脂联素水平的影响

目的 观察不同剂量阿托伐他汀对房颤患者hs-CRP、NO、IL-6、脂联素水平的影响.方法 选取合肥市第三人民医院2012年12月至2014年2月住院的房颤患者80例,随机分为20 mg阿托伐他汀组和40 mg阿托伐他汀组,每组40例,观察两组患者治疗前后超敏C-反应蛋白（hs-C RP）、一氧化氮（NO）、白细胞介素-6（IL-6）、脂联素和左房内径的变化.结果 治疗前、后,20 mg阿托伐他汀组hs-CRP水平分别为（6.25±1.75）mg/L和（5.23±1.85）mg/L,IL-6水平分别为（14.53±2.32）ng/L和（13.02±2.12）ng/L;40 mg阿托伐他汀组hs-CRP水平分别为（6.45±1.65）mg/L和（4.25± 1.72）mg/L,IL-6水平分别为（14.65±2.42）ng/L和（11.12±1.25）ng/L.两组治疗后各项水平均明显降低,与治疗前比较差异有统计学意义（P＜0.05）,且40 mg阿托伐他汀组降低更明显,与20 mg阿托伐他汀组比较差异有统计学意义（P＜0.05）.20 mg阿托伐他汀组NO水平治疗前后分别为（26.30±1.65）mmol/L和（35.25±1.78）mmol/L,脂联素水平分别为（7.26±3.25）μg/L和（8.56±3.12）μg/L.两组治疗后各项水平均明显升高,与治疗前比较差异有统计学意义（P＜0.05）,且40 mg阿托伐他汀组升高更明显,与20 mg阿托伐他汀组比较差异有统计学意义（P＜0.05）.结论 大剂量阿托伐他汀能显著改变房颤患者血清炎症因子水平,且呈剂量依赖性.     

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。     

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.