赤芍总苷对人黑色素瘤细胞株凋亡诱导的作用机制

目的 观察赤芍总苷(TPG)对人黑色素瘤A375细胞凋亡的影响并探讨其机制.方法 将12.5、25、50、100、200 mg/L TPG分别加入体外培养的黑色素瘤细胞,对照组加等量生理盐水,孵育24、48 h后MTT测定细胞生长抑制率;25 mg/L TPG 孵育细胞48 h,收集细胞,FCM测定细胞凋亡率;RT-PCR和Western blot分别测定Caspase-3、Bcl-2、Bax、Fas、FasL mRNA和蛋白的表达水平.结果 TPG抑制A375细胞生长作用明显,25 mg/L TPG孵育黑色素瘤细胞48 h后,细胞凋亡率增高,Caspase-3、Bax、Fas、FasL mRNA和蛋白表达也明显升高,Bcl-2 mRNA和蛋白表达水平下降,Bcl-2/Bax比值显著降低(均P＜0.05).结论 TPG可诱导黑色素瘤肿瘤细胞凋亡,其机制与上调Caspase-3、Fas和FasL表达水平,下调Bcl-2,降低Bcl-2/Bax比值密切相关.     

丹参酮ⅡA介导p38MAPK信号转导诱导人肝癌细胞凋亡

目的: 研究丹参酮ⅡA诱导人肝癌细胞凋亡和凋亡相关基因表达的p38MAPK信号转导通路, 揭示其抗肝癌的部分机制.方法: 4、8、16 mg/L丹参酮ⅡA分别作用人肝癌SMMC-7721细胞48 h后, 免疫荧光染色观察细胞凋亡情况; 琼脂糖凝胶电泳观察凋亡细胞特征性DNA条带; 流式细胞仪法(Flowcytometry, FCM)检测细胞凋亡和细胞周期; 荧光定量PCR检测Fas和Caspase-3基因mRNA的表达水平; 并比较阻断p38MAPK信号通路后丹参酮ⅡA对肝癌细胞凋亡和Fas和Caspase-3基因mRNA的表达.结果: 丹参酮ⅡA作用48 h后, 荧光显微镜下观察到经Hoechst染色的典型凋亡细胞. 琼脂糖凝胶电泳可见凋亡细胞DNA呈规律性的梯状条带. 4、8、16 mg/L浓度丹参酮ⅡA作用人肝癌细胞后的细胞凋亡率分别为12.83%±1.51%, 17.86%±2.70%和29.24%±7.58%, 与对照组6.30%±2.08%比较均有显著性差异( P<0.01); 阻断p38MAPK信号通路后, 凋亡率和G0/G1期细胞比例明显降低( P<0.01). 8 mg/L丹参酮ⅡA作用人肝癌细胞48 h后Fas mRNA和Caspase-3 mRNA的表达明显上升; 阻断p38MAPK信号通路后, 丹参酮ⅡA作用人肝癌细胞的Fas mRNA和Caspase-3 mRNA的表达明显下降.结论: 丹参酮Ⅱ A 能诱导人肝癌细胞株SMMC-7721凋亡, 阻滞肝癌细胞于G0/G1期. 通过p38MAPK信号转导通路上调Fas、Caspase-3 mRNA的表达可能是其诱导肝癌细胞凋亡的重要机制.     

姜黄素联合奥沙利铂对人胃癌BGC-823细胞的作用

目的观察姜黄素联合奥沙利铂增强对人胃癌BGC823细胞生长抑制及杀伤作用,并探讨其与Fas蛋白的关系。方法采用不同浓度姜黄素和奥沙利铂单独或联合作用于BGC-823胃癌细胞,分别应用CCK-8法检测细胞生长抑制率,Annexin V-FITC/PI双染色检测BGC-823细胞凋亡率,流式细胞术检测Fas蛋白表达及采用分光光度法检测Caspase-3酶活性变化。结果姜黄素和奥沙利铂明显抑制细胞的增殖,呈剂量依赖性,联合作用组显著高于单独用药组;两药均可增强胃癌BGC-823细胞凋亡率,联合作用组显著高于单独用药组;两药均可增强Fas蛋白表达。联合作用组显著高于单独用药组;两药均可增强Caspase-3酶活性,联合作用组显著高于单独用药组。结论姜黄素联合奥沙利铂可显著增强对BGC823胃癌细胞的增殖抑制作用,并可增强诱导细胞凋亡作用,其机制可能与上调Fas蛋白的表达、增强Caspase-3活性有关。     

Fas/FasL途径在氟致人神经母细胞瘤SH-SY5Y细胞凋亡中的作用

目的 探讨Fas/FasL途径在氟致人神经母细胞瘤SH-SY5Y细胞凋亡中的作用.方法 用不同剂量氟化钠[NaF,0(对照)、20、40、80 mg/L].SH-SY5Y细胞进行染毒,24 h后检测细胞存活率、凋亡率和Fas、FasL mRNA表达;选择40 mg/L NaF组,观察在Fas受体激动剂(CH11)或拮抗剂(ZB4)作用下细胞凋亡率及Fas、FasL mRNA表达水平的改变.结果 40、80 mg/L组细胞存活率[(84.63±2.57)%、(69.04±5.63)%]明显低于对照组(100.00%),组间比较差异有统计学意义(P<0.01);细胞凋亡率随染毒剂量的升高呈上升趋势.40、80 mg/L组细胞凋亡率[(8.54±1.95)%、(17.94±2.71)%]明显高于对照组[(3.32±1.33)%],组间比较差异有统计学意义(Jp<0.05);NaF能不同程度地上调Fas、FasL mRNA表达,使Fas/β-actin[40mg/L组(0.94±0.51)、80 mg/L组(0.99±0.12)]和FasL/β-actin[40 mg/L组(0.96±0.42)、80 mg/L组(0.99±0.24)]比值增加.与对照组[Fas/β-actin(0.50±0.33)、FasL/β-actin(0.58±0.23)]比较,差异均有统计学意义(P<0.05).在对细胞凋亡率和Fas、FasL mRNA表达水平的影响中,NaF与CH11之间存在协同作用(,值分别为32.89、18.46、14.69,P<0.01),NaF与ZB4之间存在拈抗作用(F值分别为5.73、24.26、10.17,P<0.05或<0.01).结论 NaF可诱导SH-SY5Y细胞凋亡,Fas/FasL途径在NaF诱导SH-SY5Y细胞凋亡中起重要作用.     

缬草波春诱导MKN-45胃癌细胞凋亡

目的:研究缬草波春诱导胃癌细胞凋亡,探讨其诱导凋亡与半胱氨酸酶(Caspase)及生存素(Survivin)mRNA、P53蛋白、Survivin蛋白表达的关系.方法:以100 mg/L的缬草波春作用于加Caspase-3抑制剂、Caspase-8抑制剂、Caspase-9抑制剂和未加Caspases抑制剂培养的MKN-45细胞24,48和72 h,用流式细胞仪分别检测细胞凋亡率;不同浓度的缬草波春(5,10,25,50,100 mg/L)作用MKN-45细胞不同时间(24,48,72 h)后,用tripure提取液提取细胞RNA,用RT-PCR法,检测Survivin mRNA的表达.不同浓度缬草波春(50和100 mg/L)作用MKN-45胃癌细胞株24 h后,用免疫组化的方法,检测P53蛋白和Survivin蛋白的表达.结果:单用Caspase抑制剂组,作用24,48和72 h对MKN-45细胞凋亡率无明显影响,与对照组比较差异无显著意义.Caspase-3抑制剂、Caspase-9抑制剂与缬草波春联合应用后24,48和72 h使MKN-45细胞凋亡率高于对照组(24 h:5.73%,5.41% vs 4.38%,P＜0.01;48 h:6.88%,6.32% vs 4.35%,P＜0.01;72 h:7.72%,8.62% vs 4.54%,P＜0.01),低于缬草波春组(24 h:5.73%,5.41% vs 8.14%,P＜0.01;48 h:6.88%,6.32% vs 12.31%,P＜0.01;72 h:7.72%,8.62% vs 26.41%,P＜0.01),与对照组及缬草波春组比较差异均有显著意义(P＜0.01).Caspase-8抑制剂与缬草波春联合应用后24,48和72 h MKN-45细胞凋亡率明显增加,与对照组比较差异有显著意义(8.02% vs 4.38%,P＜0.01;11.05% vs 4.35%,P＜0.01;24.86% vs 4.54%,P＜0.01),与单用缬草波春组比较差异无显著意义.缬草波春降低MKN-45胃癌细胞株Survivin mRNA的表达,并有浓度依赖性和时间依赖性,而且使MKN-45胃癌细胞株P53蛋白表达增加,Survivin蛋白表达降低,均有浓度依赖性.结论:缬草波春可诱导MKN-45细胞凋亡,其作用可部分被Caspase-3,Caspase-9抑制剂所抑制,但不能被Caspase-8抑制剂所抑制.缬草波春诱导MKN-45胃癌细胞株凋亡与P53蛋白表达提高及Survivin mRNA和Survivin蛋白低表达降低有关.     

奥曲肽对SGC-7901胃癌细胞中Fas,FasL及P53表达的影响

目的:探讨奥曲肽(OCT)对胃癌细胞SGC-7901中Fas,FasL,P53,P21,P27和C-Myc表达的影响.方法:流式细胞术和RT-PCR法分别用于检测经OCT(1×10-7 mol/L)处理前后胃癌细胞SGC-7901中Fas,FasL,P53,P21,P27,c-Myc阳性癌百分率、mRNA表达和蛋白表达及细胞周期G0/G1、S、G2/M的变化.结果:胃癌细胞SGC-7901经OCT诱导6、12、24和48 h垢,Fas和FasL mRNA表达均明显增加,P53 mRNA表达则显著减少,而P21,P27和c-Myc mRNA表达均无明显变化;胃癌细胞SGC-7901经OCT诱导12 h后,Fas和FasL蛋白相对表达强度也显著增加,P53蛋白相对表达强度则明显降低(5.5±0.3 vs 3.2±0.1,5.1±0.3 vs 4.5±0.1.3.3±0.2 vs 4.9±0.3,P＜0.05或0.01),而P21,P27和c-Myc蛋白相对表达强度均无明显改变.细胞周期G0/G1、S、G2/M在OCT处理前后的变化并不明显.结论:OCT能上调SGC-7901胃癌细胞中Fas和FasL表达,下调突变型p53表达,是其诱导凋亡作用的重要机制之一.     

ERK通路对胃癌细胞顺铂敏感性的调节作用

目的:研究在人胃癌细胞中,细胞外信号调节蛋白激酶(extracellular signal-regulated kinase,ERK)通路对人胃癌细胞顺铂敏感性的影响.方法:采用MTT法测定顺铂对两种胃癌细胞MGC-803、BGC-823的增殖抑制影响,测定PD98059作用BGC-823细胞后顺铂对细胞的增殖抑制影响.Western blot方法检测MGC-803、BGC-823细胞中谷胱甘肽-S-转移酶π(glutathione S-transferases π,GGST-π)蛋白的表达;及PD98059作用BGC-823细胞24 h后BGC-823细胞中p-ERK、GsT-π蛋白的表达.结果:顺铂作用两种胃癌细胞7 2 h后.MGC-803,BGC-823细胞的IC50值分别为0.71和1.21 mg/L,且MGC-803细胞的增殖率明显低于BGC-823细胞的增殖率(P<0.05).MGC-803细胞顺铂的敏感性高于BGC-823细胞.MGC-803细胞不表达GST-π蛋白,BGC-823细胞强表达GST-兀蛋白.20 μmol/LPD98059作用BGC-823细胞24 h后,p-ERK蛋白表达明显下调,GST-π蛋白表达亦明显下调.20 μmol/L PD98059作用BGC-823细胞24 h后,加入顺铂培养48 h,BGC-823+PD98059组增殖率明显低于对照组,BGC-823细胞对顺铂的敏感性明显增强.结论:下调胃癌细胞GST-π蛋白的表达可增强其对顺铂的敏感性;抑制胃癌细胞中ERK通路的活化,可以降低其细胞内GST-π蛋白表达;ERK通路通过调节人胃癌细胞GST-π基因表达影响其对顺铂的敏感性.     

双膦酸盐类药物对胃癌细胞生长增殖的作用机制

目的检测双膦酸盐类药物唑来膦酸对胃癌细胞生长增殖的研究机制。方法培养人胃癌细胞株MKN-28、SGC-7901和BGC-823,将细胞分为对照组和药物处理组,MTT法检测10、20、40、80μmol/L唑来膦酸对细胞株的影响。人胃癌细胞株加入10~80μmol/L的唑来膦酸,对照组不加药物,孵育1、3、6、12、24 h后计算不同浓度和时间对细胞的影响;人胃癌细胞株SGC-7901加入40μmol/L的唑来膦酸培养24 h后,用流式细胞仪检测细胞凋亡情况,Western印迹检测半胱氨酸蛋白酶(Caspase)-3、Caspase-9、Bcl-2蛋白的表达。结果 10、20、40、80μmol/L的唑来膦酸作用于胃癌细胞株(BGC-823、SGC-7901、MKN-28),唑来膦酸的半抑制浓度(IC50)为40μmol/L,用10~80μmol/L的唑来膦酸作用于BGC-823、SGC-7901、MKN-28胃癌细胞株1、3、6、12、24 h后,可见唑来膦酸抑制人胃癌细胞的生长且有时间和浓度的依赖性,唑来膦酸对胃癌正常黏膜细胞GES-1无抑制作用;人胃癌细胞SGC-7901经40μmol/L的唑来膦酸作用24 h后,流式细胞仪检测发现唑来膦酸处理组细胞凋亡情况显著高于对照组;经40μmol/L唑来膦酸作用后的人胃癌细胞中Caspase-3、Caspase-9蛋白表达量明显升高,而Bcl-2蛋白表达量与对照组相比明显减少。结论唑来膦酸能抑制胃癌细胞的生长且有时间和剂量依赖性,唑来膦酸可以促进细胞凋亡。     

芒柄花素调节HIF-1α/VEGF信号通路对胃癌细胞增殖、凋亡和肿瘤血管生成拟态的影响

目的 探讨芒柄花素(FMN)调节低氧诱导因子-1α/血管内皮生长因子(HIF-1α/VEGF)信号通路对胃癌细胞增殖、凋亡和肿瘤血管生成拟态(VM)的影响。方法 采用实时荧光定量PCR法检测人胃癌细胞株BGC-823、MGC-803、MKN28、SGC-790和人胃黏膜上皮细胞株GES-1中HIF-1α、VEGF的m RNA表达水平。将生长良好的MGC-803细胞分别设为对照组、30μmol/L FMN组、50μmol/L FMN组、80μmol/L FMN组、80μmol/L FMN+HIF-1α过表达质粒(pc-HIF-1α)组、80μmol/L FMN+阴性对照(pc-vector)组并进行相应处理。MGC-803细胞经上述药物处理及质粒转染后,采用MTT法计算MGC-803细胞增殖率,实时荧光定量PCR法检测各组MGC-803细胞中HIF-1α、VEGF的mRNA表达水平,流式细胞仪检测MGC-803细胞凋亡率,成管实验检测VM形成情况,蛋白质印迹法检测MGC-803细胞中VEGF、HIF-1α的蛋白表达水平。结果 各种人胃癌细胞株中HIF-1α、VEGF的mRNA表达水平均较...     

异硫氰酸苯乙酯对胃癌细胞体外抑制作用相关研究

[目的]研究异硫氰酸苯乙酯（PEITC）体外实验中对人胃癌BGC-823细胞的增殖抑制作用及诱导其凋亡相关分子机制.[方法]应用MTT法、Annexin V/PI双染法检测PEITC人胃癌BGC-823细胞增值以及凋亡的影响;应用RT-PCR以及Western Bolt检测PEITC诱导胃癌细胞凋亡相关基因蛋白的表达情况.[结果]PEITC作用人胃癌细胞BGC-823给药24 h后,与空白组比较,能显著抑制胃癌细胞的增殖,抑制作用与浓度和时间成依赖关系,诱导胃癌细胞的凋亡,能上调Bax表达,下调Bcl-2、Bcl-xl、Survivin等基因表达,激活Caspase-3、Caspase-9、PARP活性.[结论]PEITC能有效抑制人胃癌BGC-823细胞的增殖,其机制可能是通过激活Caspase家族蛋白酶活性而诱导胃癌细胞凋亡.     

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.