血管外膜源一氧化氮对内皮素-1诱导的血管平滑肌增殖的影响

目的观察血管外膜生成的一氧化氮(NO)对内皮素-1(ET-1)诱导的血管平滑肌(VSM)增殖的影响,以探讨血管外膜源NO对血管结构重塑调节的意义.方法取大鼠胸主动脉,去除内皮,分以下几组进行组织孵育10 h(1)完整外膜血管组;(2)单纯中膜组;(3)中膜与剥离的外膜共育组;(4) 中膜与用L-N-硝基精氨酸(L-NNA)预处理的外膜共育组.每例胸主动脉剪为二段,分两个亚组ET (10-7mol/L)组和对照组.3H-胸腺嘧啶(3H-TdR)掺入法检测各组VSM的细胞增殖.另取大鼠腹主动脉外膜,用10-8和10-7mol/ L ET-1刺激4 h.Griess法测血管外膜生成的亚硝酸盐(NO2-)含量,3H-L-精氨酸(3H-L-Arg)标记的同位素法测定外膜一氧化氮合酶(NOS)活性.结果 (1)各ET亚组3H-TdR掺入比相应对照组分别增加48.8%～71.9%.(2)在10-7mol/L ET-1刺激下,完整外膜组及中膜+外膜组的3H-TdR掺入分别比单纯中膜组低 21.3%和24.5%;中膜+L-NNA预处理的外膜组3H-TdR掺入分别比中膜+外膜组及完整外膜组高30.8%和25.4%,而与单纯中膜组差异无显著性.(3)与对照组相比,10-8和10-7mol/L的ET-1使外膜NOS活性分别增加124%和177%;使外膜生成的NO2-含量分别增加88%和225%.结论实验结果表明血管外膜生成的NO可抑制ET-1刺激的VSM的增殖,其抑制作用为ET-1激活的血管外膜NOS/NO途径所介导.提示血管外膜源NO可能参与心血管疾病过程中血管重塑的调节.     

高血压大鼠主动脉一氧化氮合成途径的变化

目的 观察高血压大鼠主动脉内膜，中膜和外膜一氧化氮合成途径的改变，并探讨其可能的病理生理意义。方法 Wistar大鼠缩窄腹主动脉复制高血压模型，动物随机分为对假手术组和高血压。取大鼠主动脉，分离血管内膜，中膜和外膜。分别测定其亚硝酸盐（NO2^-)生成量，一氧化氮合酶（NOS）活性及L－精氨酸（L－Arg)转运，免疫组化染色检测诱导型一氧化氮合酶（iNOS)的分布。结果 与假手术组相比，高血压大鼠血中一氧化氮代谢产物（NOx)高26．2％（P＜0．05）；主动脉NO2^-生成低65．8％（P＜0．01），中膜及外膜孵育液的NO2^-生成量分别高59．6％和123．6％（均P＜0．01）；主动脉内膜NOS活性低59．3％（P＜0．01），中膜和外膜NOS活性分别高62．6％和118．7％（均P＜0．01），血管内膜L－Arg转运率低62．5％（P＜0．01），中膜和外膜L－Arg转运率分别高53．7％和99．8％（均P＜0．01）。iNOS免疫组化染色显示，高血压大鼠血管中膜和外膜尤其是外膜iNOS阳性染色明显增强。结论 高血压大鼠血管管一氧化氮合成与代谢发生改变，血管内膜L－Arg/NOS/NO途径受抑，而中膜和外膜尤其是外膜的L－Arg/NOS/NO系统的活性增强，血管生成的NO增多。提示血管中膜和外膜源NO增多在高血压时可能具有一定的代偿作用。     

血管紧张素Ⅱ刺激肝星状细胞核酸、蛋白质及胶原合成

目的 研究不同浓度血管紧张素Ⅱ（AngⅡ)对大鼠肝星状细胞（HSC）增殖和胶原合成的影响。方法 采用酶法分离大鼠肝星状细胞（HSC），应用^3H-TdR（胸腺嘧啶核苷）、^3H-Leu(亮氨酸）、^3H-Pro（脯氨酸）掺入检测10^-9-10^-5mol/L不同浓度AngⅡ对HSC的DNA、蛋白质及脯氨酸合成的影响。结果 10^-9-10^-6mol/L AngⅡ能促进HSC对^3H-TdR的掺入率（P＜0．05），但只有10^-6mol/L和10^-7mol/L浓度的AngⅡ才能显著增加HSC对^3H-Leu的掺入率（P＜0．01）；而10^-9-10^-6mol/L AngⅡ均能促进HSC对^3H-Pro的掺入率（P＜0．05），且呈剂量依赖关系。结论 适当浓度的AngⅡ能促进HSC增殖和胶原合成。     

舒芬太尼对2型糖尿病大鼠离体胸主动脉血管内皮功能的影响

目的：舒芬太尼对2型糖尿病大鼠离体胸主动脉血管内皮功能的影响。方法将16只健康雄性Wistar大鼠随机分为正常组（N组）、糖尿病组（D组）,每只大鼠迅速分离胸主动脉并取4段动脉血管环,4段血管环分别给予生理盐水（C组）、舒芬太尼7×10^-11mol/L（S1组）、2×10^-10mol/L（S2组）、1×10^-9mol/L（S3组）处理,采用离体血管环灌流法,通过比较KCl预收缩和给予累积浓度的NE收缩观察血管张力G1、G2变化幅度,计算血管环收缩幅度（G2/G1×100％）来反映血管内皮功能;随后采用ELISA酶联免疫法,对各组血管环组织进行研磨、离心取上清液,观察不同浓度舒芬太尼作用后血管内皮一氧化氮（NO）、一氧化氮合酶（NOS）定量表达情况,来反映对血管内皮的作用效果。结果与NC组相比,NS2组、NS3组血管环收缩幅度降低,组织匀浆NO、NOS表达升高（P＜0．05）;与DC组相比,DS1组、DS2组、DS3组收缩幅度降低,组织匀浆NO、NOS表达升高（P＜0．05）;与DS2组相比,DS3组收缩幅度组显著降低,组织NO、NOS明显升高（P＜0．05）。结论不同浓度舒芬太尼对糖尿病大鼠离体胸主动脉血管有抑制收缩作用,高浓度作用显著,其机制可能与血管内皮因子NO表达升高有关,而NOS是其生物转化的关键酶。     

醛固酮对血管外膜诱导型一氧化氮合酶/一氧化氮通路影响的实验研究

目的观察醛固酮对血管外膜诱导型一氧化氮合酶（iNOS）／一氧化氮（NO）通路的影响及作用机制。方法取sD大鼠胸主动脉外膜,分别给予不同浓度醛固酮（ALD）10^-8～10^-6mol／L、ALl）＋螺内酯以及ALD＋RU486进行孵育,此外在给予脂多糖激活血管外膜iNOS／NO的情况下,观察以上各组药物刺激后iNOS／NO系统的变化。与上述药物共同孵育6h后通过Griess法测定相对稳定的代谢产物硝酸盐和亚硝酸盐（NOx）代表NO的产生量,采用[^3H]-L-精氨酸标记的同位素法测定外膜iNOS活性。结果（1）NOx产生的变化：ALD刺激后血管外膜NOx生成无明显变化。用螺内酯拮抗盐皮质激素受体后,高浓度ALD组（10～～10^-6mol／L）血管外膜NOx产生呈下降趋势（P〈0．05）。用RU486拮抗糖皮质激素受体后随ALD浓度增加NOx生成量也呈浓度依赖性增加（P〈0．01）。脂多糖刺激后上述趋势更为明显。（2）iNOS活性的变化：ALD刺激后iNOS活性无明显变化,螺内酯刺激后血管外膜iNOS活性有下降趋势,但无统计学意义。而RU486刺激后血管外膜iNOS活性显著增加（P〈0．05）。同时给予脂多糖刺激后,螺内酯＋ALD组血管外膜iNOS活性显著下降（P〈0．01）,ALD＋RU486组血管外膜iNOS活性显著增加（p〈0．05）。结论ALD主要通过盐皮质激素受体和糖皮质激素受体通路两种途径直接影响血管外膜iNOS／NO系统,醛固酮作用于盐皮质激素受体能够诱导iNOS激活、刺激NO产生,作用于糖皮质激素受体抑制iNOS／NO激活。     

肾上腺髓质素对血管紧张素Ⅱ促血管外膜成纤维细胞胶原生成作用的影响

目的探讨肾上腺髓质素（ADM）对血管紧张素Ⅱ（AngⅡ）诱导的血管外膜成纤维细胞胶原生成的影响及机制。方法体外培养大鼠主动脉外膜成纤维细胞,通过放射免疫法测定培养上清中ADM含量,采用酶联免疫吸附法（ELISA）测定培养上清中Ⅰ、Ⅲ型胶原蛋白含量,用逆转录一聚合酶链反应（RT—PCR）及Western印迹法检测转化生长因子β1（TGFβ1）和基质金属蛋白酶-2（MMP-2）mRNA及蛋白的表达。结果AngII呈剂量依赖性地刺激血管外膜成纤维细胞分泌ADM,在AngⅡ（10^-6mol／L）刺激前30min加入氯沙坦或（和）PD123319,氯沙坦（10^-5mol／L）可明显降低AngⅡ刺激的ADM分泌,其抑制率为45％（P〈0．01）,而PD123319（10mmol／L）作用后抑制率仅为3％（P〉0．05）,氯沙坦＋PD123319组与单独氯沙坦组相比差异无统计学意义（P〉0．05）;AngⅡ显著增加培养上清中Ⅰ、Ⅲ型胶原蛋白含量,ADM呈剂量依赖地抑制AngⅡ上述作用,其中ADM（10“mol／L）组中I、Ⅲ型胶原合成分别抑制了30％和31％（P〈0．01）,ADM（10^-7mol／L）组则分别抑制了43％和42％（P〈0．01）。ADM受体拈抗剂ADM22-52可增强AngII上述作用,Ⅰ、Ⅲ型胶原合成分别增加了38％和43％（P〈0．01）;ADM呈剂量依赖性抑制AngⅡ刺激的TGFβ1mRNA及蛋白表达,其中ADM（10^-8mol／L）组中TGFβ1mRNA及蛋白表达分别抑制了55％和45％（P〈0．01）,ADM（10^-7mol／L）组则分别抑制了70％和59％（P〈0．01）;AngⅡ明显下调细胞内MMP-2mRNA及蛋白表达,ADM呈剂量依赖性抑制上述作用,其中10^-8mol／LADM组细胞内MMP-2mRNA及蛋白表达分别增加了1．0和0．9倍。结论AngⅡ可刺激血管外膜成纤维细胞释放ADM,而自分泌旁分泌的ADM可能通过下调细胞内TGFN表达和上调MMP-2表达,抑制AngⅡ刺激的Ⅰ、Ⅲ型胶原蛋白生成,从而发挥有效的抗血管重构作用。     

转VEGF基因对血管损伤后平滑肌细胞增殖和表型的影响

目的：观察局部转染pAdTrack CMV-VEGF165对动脉粥样硬化兔血管损伤后平滑肌细胞增殖和表型转变的影响。方法：90只新西兰大白兔分为3组,I组（30只）单纯拉伤腹主动脉;Ⅱ组（30只）拉伤后局部转染真核表达质粒pAdTrack CMV;Ⅲ组（30只）拉伤后局部转染pAdTrack CMV-VEGF165;每组按实验终点（术后3d、1周、2周、4周和8周）分为5个亚组,术前1周开始予高脂饮食至实验终点,取拉伤段血管用于^3H-TdR掺入实验、病理学检测和电镜观察平滑肌细胞表型变化。结果：^3H-TdR掺入实验结果显示,I组和Ⅱ组在血管拉伤后3d ^3H-TdR掺入量增加（P＜0．05）,2周时达到高峰（P＜0．01）,以后逐渐下降,8周时恢复至正常,而Ⅲ组血管组织术后3d同样出现^3H-TdR掺入增加（P＜0．05）,术后1周时^3H-TdR掺入值明显低于I组和Ⅱ组（P＜0．01）,术后4周时^3H-TdR掺入量接近正常;透射电镜观察显示I组和Ⅱ组从术后3d开始出现合成型VSMC,2周时达到高峰,80％以上为合成型,至4周时,仍以合成型平滑肌细胞为主（60％）,而Ⅲ组血管组织术后3d时可见少量合成型平滑肌细胞（10％）,1周时合成型VSMC约占30％,术后2周时90％为收缩型平滑肌细胞,4周时已无合成型平滑肌细胞。结论：局部转染VEGF165基因可抑制平滑肌细胞增殖和表型改变,缩短修复时程。     

血管紧张素—（1—7）在内皮素诱导血管平滑肌细胞增殖反应中的作用

目的：探讨血管紧张素－（1－7）[Ang-(1-7)]在内皮素－1（-1)诱导血管平滑肌细胞增殖反应中的作用。方法：在ET－1诱导培养的SD大鼠主动脉血管平滑肌细胞模型中,应用Ang-(1-7)通过,测定^3H-胸腺嘧啶（^3H-TdR)掺入的方法,观察血管平滑肌细胞增殖情况。结果Ang-(1-7)呈剂量性抑制ET－1诱导血管平滑肌细胞的DNA民,其作用受体不是血管紧张素Ⅱ受体1（AT1）或血管紧张素Ⅱ受体2（AT2）,而是通过一种特殊受体介导。结论：Ang-(1-7)能抑制T－1诱导的血管平滑肌增殖。     

肾上腺髓质素对血管紧张素Ⅱ诱导的血管平滑肌细胞MCP-1表达的影响

目的观察肾上腺髓质素（ADM）对血管紧张素Ⅱ（AngⅡ）诱导的大鼠主动脉血管平滑肌细胞（VSMCs）单核细胞趋化蛋白-1（MCP-1）表达的影响。方法体外培养大鼠主动脉VSMCs。实验分组：空白对照组（A组）;1×10^-7mol/L ADM组（B组）;1×10^-7mol／LAngⅡ组（C组）;1×10^-8mol／L ADM＋1×10^-7mol／L AngⅡ组（D组）;1×10^-7mol／LADM＋1×10^-7mol／LAng Ⅱ组（E组）。采用逆转录聚合酶链反应技术测定细胞中MCP-1 mRNA的表达量。结果C组MCP-1 mRNA的表达量高于A组（P〈0．05）。D组、E组MCP-1 mRNA的表达量低于C组（P〈0．05）。结论ADM对Ang Ⅱ诱导的大鼠主动脉VSMCs MCP-1的表达起明显的抑制作用,这可能是其发挥抗炎、心血管保护作用机理中的一个重要途径。     

过氧亚硝基阴离子分解催化剂对衰老大鼠血管舒张功能的保护作用

目的利用过氧亚硝基阴离子（ONOO^-）分解催化剂FeTMPyP探讨衰老大鼠血管舒张功能障碍的可能机制。方法选取雄性SD大鼠,随机分为成年组（3-4月,n=8）、衰老组（18-20月,n=8）及给予FeTMPyP的衰老组（n=6）;制备离体胸主动脉环,观察血管舒张功能;采用免疫组织化学法和Westernblot法测定血管组织中可代表ONOO^-生成的标记物3-硝基酪氨酸（3-NT）的表达。结果与成年组大鼠比较,衰老组大鼠胸主动脉环对10^-9-10^-5mol／L累积浓度的内皮依赖性舒张剂乙酰胆碱（ACh）的最大舒张程度显著下降[（29．74％±8．28％）vs（69．52％±5．51％）,P〈0．001];对10^-9-10^-5mol/L累积浓度的非内皮依赖性舒张剂硝普钠（SNP）的最大舒张程度也显著下降[（92．01％±3．19％）vs（99．26％±1．33％）,P〈0．001]。与成年组大鼠比较,衰老组大鼠血管组织中3-NT蛋白表达增加（P〈0．05）。给予FeTMPyP后,衰老大鼠血管组织中3-NT蛋白表达下降（P〈0．01）;抑制ONOO^-的生成后,衰老大鼠胸主动脉环对累积浓度ACh的最大舒张程度显著升高[（65．96％±11．36％）vs（29．74％±8．28％）,P〈0．001],对累积浓度SNP的最大舒张程度也显著升高[（98．15％±2．79％）vs（92．01％±3．19％）,P〈0．001]。结论FeTMPyP改善了衰老大鼠血管舒张功能,提示ONOO^-可能在衰老大鼠血管功能障碍中起重要作用。     

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。     

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.     

Study of constancy of hydrogen-consuming flora of human colon

The constancy of the hydrogen consuming flora of the human colon was studied in 15 healthy subjects via two measurements obtained 18 to 36 months apart. Hydrogen disappearance rate and the major products of H₂-consuming bacteria, methane and sulfide, were measured during incubation of fecal homogenates with excess hydrogen and sulfate. In 11/15, the hydrogen consumption rate and the predominant hydrogen-consuming pathway (methanogenesis, sulfate reduction, or neither) remained constant. However, major shifts in these pathways were observed in four subjects, with two losing and two gaining the ability to produce methane. Methanogenesis was associated with the highest hydrogen consumption rate. This study demonstrates that clinically unrecognizable, major alterations of the colonic flora occur in healthy subjects. Understanding of the factors responsible for these alterations might allow for therapeutic manipulation of the colonic flora.Supported in part by the Department of Veterans Affairs and NIDDKD RO1 DK 13309-25.