不同抗血小板治疗对经皮冠状动脉介入术后氯吡格雷抵抗患者血小板miR-223、血小板抑制率及血小板活化指标的影响

目的:探讨不同抗血小板治疗方案对经皮冠状动脉介入术(PCI)后氯吡格雷抵抗患者血小板微小RNA-223(miR-223)、血小板抑制率及血小板活化指标的影响。方法:将160例PCI后氯吡格雷抵抗患者随机分为氯吡格雷双倍组(n=80,氯吡格雷150 mg,每日1次)和替格瑞洛组(n=80,替格瑞洛90 mg/次,每日2次)。比较两组治疗前后血小板抑制率、血小板miR-223、血小板α颗粒表面膜糖蛋白(CD62P)、活化血小板糖基化复合物(PAC-1)的变化。随访6个月,记录两组主要不良心血管事件(MACE)、出血事件及呼吸困难的发生情况。结果:治疗7 d、30 d后,替格瑞洛组血小板抑制率均明显高于氯吡格雷双倍组(P均0.05)。治疗30 d后,替格瑞洛组血小板miR-223、CD62P、PAC-1表达水平均明显低于氯吡格雷双倍组(P均0.05)。随访6个月,替格瑞洛组MACE发生率明显低于氯吡格雷双倍组(3.75%对13.75%,P0.05);两组出血事件发生率的差异无统计学意义,但替格瑞洛组呼吸困难发生率明显高于氯吡格雷双倍组(11.25%对16.25%,P0.05)。结论:对于PCI后氯吡格雷抵抗的冠状动脉粥样硬化性心脏病患者,替格瑞洛较双倍剂量氯吡格雷能够更好地抑制血小板聚集,减少MACE,且不增加出血风险。但替格瑞洛易引起呼吸困难,临床应予以足够重视。     

复杂冠状动脉病变介入治疗患者应用替格瑞洛的临床疗效观察

目的评价复杂冠状动脉病变PCI患者应用替格瑞洛的有效性及安全性。方法选择2013年2月~2015年8月在我院心内科住院的复杂冠状动脉病变PCI患者204例,冠状动脉造影后随机分为替格瑞洛组98例和氯吡格雷组106例。替格瑞洛组术前给予替格瑞洛负荷剂量180mg口服,术后维持剂量90mg口服,2次/d;氯吡格雷组术前给予氯吡格雷负荷剂量300mg口服,术后维持剂量75mg口服,1次/d。观察术后12个月主要不良心血管事件(MACE),包括支架内血栓形成、再发心绞痛、再发心肌梗死和再次血运重建;安全性终点包括TIMI出血事件以及呼吸困难发生率。结果随访12个月,替格瑞洛组MACE发生率低于氯吡格雷组,但差异无统计学意义(14.3%vs 21.7%,P=0.170)。替格瑞洛组再发心肌梗死及支架内血栓形成发生率明显低于氯吡格雷组(1.0%vs6.6%,P=0.039;0vs 4.7%,P=0.029),呼吸困难发生率明显高于氯吡格雷组(6.1%vs 0.9%,P=0.042)。替格瑞洛组出血事件发生率较氯吡格雷组高,但差异无统计学意义(P=0.367)。结论复杂冠状动脉病变PCI患者应用替格瑞洛获益明显,与氯吡格雷比较进一步降低MACE,不增加出血风险,但呼吸困难发生率较高。     

替格瑞洛与氯吡格雷序贯治疗对STEMI急诊PCI患者血小板聚集率及MACE的影响

目的探讨行急诊经皮冠状动脉介入治疗(PCI)急性ST段抬高型心肌梗死(STEMI)患者替格瑞洛与氯吡格雷序贯治疗对血小板聚集率及主要不良心血管事件(MACE)的影响。方法选择2012年2月~2015年3月黑龙江佳木斯市中心医院心内科收治急性STEMI并行急诊PCI治疗的患者92例,随机分为替格瑞洛组(n=30)、氯吡格雷组(n=30)与序贯治疗组(n=32)3组。替格瑞洛组给予替格瑞洛口服;氯吡格雷组给予氯吡格雷口服;序贯治疗组先给予替格瑞洛口服,7 d后更改为氯吡格雷口服。检测急诊PCI术前及术后2 h、24 h、7 d及30 d时血小板聚集率,并观察患者30 d内MACE及出血事件的发生率。结果 3组患者急诊PCI术后血小板聚集率较术前均明显下降(P0.05);在术后2 h、24 h、7 d时间点替格瑞洛组血小板聚集率与氯吡格雷组比较下降更明显(P0.05);在术后2 h、24 h、7 d、30 d时间点序贯治疗组与替格瑞洛组血小板聚集率差异无统计学意义(P0.05);替格瑞洛组与序贯治疗组30d内MACE事件发生率均低于氯吡格雷组(P0.05);住院期间3组出血事件发生率差异无显著性(P0.05)。结论 STEMI患者行急诊PCI术前应用替格瑞洛抗血小板治疗,可显著抑制血小板聚集,降低30 d内MACE事件且不增加出血风险;STEMI患者PCI术一周后口服氯吡格雷替代替格瑞洛具有与替格瑞洛同样的疗效。     

替格瑞洛对急性ST段抬高型心肌梗死病人急诊PCI的疗效及安全性研究

目的探讨替格瑞洛在急性ST段抬高型心肌梗死(STEMI)行急诊经皮冠状动脉介入治疗(PCI)ICUB病人中的临床疗效及安全性。方法将200例STEMI行急诊PCI病人分为替格瑞洛及氯吡格雷组(n=100),分别予以替格瑞洛及氯吡格雷治疗,观察两组术后即刻冠脉无复流发生率、术后3个月主要心血管不良事件(MACE)、出血事件、血红蛋白、左室射血分数(LVEF)、血小板计数、药物不良反应。结果两组基础临床情况和造影特征无明显差异。替格瑞洛组在术后即刻冠脉无复流发生率明显低于氯吡格雷组,具有统计学意义(P=0.017),在术后3个月主要心血管事件低于氯吡格雷组,但无统计学意义,术后3个月出血事件高于氯吡格雷组,但无统计学意义。两组数据在术后3个月血红蛋白无明显统计学意义,替格瑞洛组血小板计数高于氯吡格雷组,具有统计学意义,在药物不良反应方面,替格瑞洛组高于氯吡格雷组,但无统计学意义(P=0.118),术后3个月LVEF替格瑞洛组高于氯吡格雷组(P=0.019)。结论急诊PCI术前负荷替格瑞洛要优于氯吡格雷,且有利于预后,可以减少MACE事件发生,替格瑞洛不良反应比氯吡格雷多见,但基本是安全的、可控的。     

替格瑞洛在急性冠脉综合征介入治疗中的应用

目的观察替格瑞洛治疗急性冠脉综合征(ACS)患者行PCI治疗的抗血小板聚集起效时间,临床疗效和安全性。方法选择我院ACS并成功完成PCI手术患者90例,随机分为氯吡格雷组(n=45)和替格瑞洛组(n=45),两组患者入院后均接受常规治疗,氯吡格雷治疗组给予氯吡格雷负荷剂600 mg,后给予氯吡格雷标准剂量(75 mg,1次/日,口服)治疗;替格瑞洛治疗组给予替格瑞洛负荷剂量180 mg,后给予替格瑞洛标准剂量(90 mg,2次/日,口服)治疗。对两组患者基线资料、危险因素以及PCI数据进行统计学分析,检测未予负荷剂量治疗前、给予负荷剂量治疗后不同时间的抗血小板聚集能力,观察两组患者6个月后的主要不良心血管事件(MACE)和出血事件的发生情况。结果替格瑞洛组负荷量180 mg比氯吡格雷组负荷量600 mg起效更快;随访术后6个月,替格瑞洛组MACE发生率显著低于氯吡格雷组(P=0.042);替格瑞洛组和氯吡格雷组的出血发生率比较无统计学意义(P0.05)。结论替格瑞洛作为一种新型的抗血小板聚集药物,起效更迅速,能够更好地降低人群中ACS患者冠状动脉介入治疗后不良心脑血管事件的发生率     

替格瑞洛对老年急性心肌梗死患者血小板功能及临床预后的影响

目的:探索替格瑞洛联合阿司匹林对老年急性心肌梗死(AMI)患者血小板功能及临床预后的影响。方法:纳入2013年10月至2014年10月期间在我院就诊的老年(≥65岁)AMI患者200例,随机分为氯吡格雷组(n=101)和替格瑞洛组(n=99),分别给予负荷量阿司匹林300 mg+氯吡格雷600 mg或阿司匹林300 mg+替格瑞洛180 mg,次日起改为维持剂量阿司匹林100 mg/d和氯吡格雷75 mg/d或替格瑞洛180 mg/d,用药前及用药后1、6和12个月分别检测血小板反应指数(PRI),观察主要不良心血管事件(MACE)和心肌梗死溶栓治疗(TIMI)出血事件。结果:共有196例患者完成随访,两组治疗前PRI无统计学差异;PCI术后6个月和12个月时两组PRI均较治疗前分别下降(P0.05);与氯吡格雷组比较,替格瑞洛组在6个月和12个月时PRI降低更加明显(P0.01);随访1年时,替格瑞洛组MACE发生率明显低于氯吡格雷组(9.2%对12.9%,P=0.01);两组TIMI出血事件发生率无差别(氯吡格雷组9.6%对替格瑞洛组10.3%,P0.05)。结论:与氯吡格雷相比,老年AMI患者服用替格瑞洛可进一步降低MACE事件,而不增加出血风险。     

替格瑞洛对不稳定型心绞痛患者经皮冠状动脉介入术围手术期血小板反应性及短期预后的影响

目的探讨替格瑞洛对不稳定型心绞痛患者经皮冠状动脉介入术(PCI)围手术期血小板反应性及短期预后的影响。方法入选不稳定型心绞痛患者424例,随机分为2组:(1)替格瑞洛组(n=212):给予替格瑞洛治疗(负荷剂量180 mg,维持剂量90 mg,每天2次,口服);(2)氯吡格雷组(n=212):给予氯吡格雷治疗(负荷剂量300 mg,维持剂量75 mg,每天1次,口服)。2组均成功接受PCI术,支架均选择国产Firebird雷帕霉素药物洗脱支架。观察2组患者PCI术围手术期血小板反应性及心肌损伤标志物心肌肌钙蛋白I(cTnI)及PCI术后90天不良事件发生情况。结果 2组患者PCI术后cTnI水平比较差异无统计学意义(P0.05)。替格瑞洛组患者花生四烯酸及二磷酸腺苷诱导的血小板聚集率均低于氯吡格雷组(P0.05);替格瑞洛组患者二磷酸腺苷诱导的血小板高反应性比例低于氯吡格雷组(P0.05)。替格瑞洛组PCI术后90天内患者再发心肌缺血发生率低于氯吡格雷组(5.19%比16.04%,P0.05)。出血事件两组比较差异无统计学意义(P0.05)。结论替格瑞洛并不降低PCI术后心肌损伤的发生,但较氯吡格雷能发挥更强的抗血小板作用,减少术后再发心肌缺血事件发生率,并不增加出血风险。     

替格瑞洛在冠状动脉复杂病变中的应用研究

目的探讨替格瑞洛对冠状动脉复杂病变介入治疗术(PCI)后患者临床预后的影响。方法入选2012年9月至2014年3月因冠心病就诊我院,冠状动脉造影证实为冠状动脉复杂病变并成功完成PCI术的患者200例,分为两组,替格瑞洛组PCI术后给予替格瑞洛抗血小板治疗;氯吡格雷组术后给予氯吡格雷,比较住院期间及术后12个月两组患者心血管不良事件(MACE)及明确的支架内血栓、再缺血及出血事件的发生率。结果最终入选患者174例,其中替格瑞洛组84例,氯吡格雷组90例。两组临床基线资料、冠状动脉造影及PCI资料差异均无统计学意义(P0.05);住院期间,两组各有1例MACE(P0.05),无明确的支架内血栓、再缺血事件的发生;PCI术后12个月,替格瑞洛组MACE的发生率低于氯吡格雷组[2.3%(2/84)比5.5%(5/90)],但差异无统计学意义(P0.05);氯吡格雷有1例支架内血栓;替格瑞洛组再缺血事件的发生率明显低于氯吡格雷组,差异有统计学意义[3.5%(3/84)比135%(12/90),P0.05)]。两组患者住院期间及术后12个月,出血事件发生率均差异无统计学意义(P0.05)。结论与氯吡格雷相比,替格瑞洛降低了冠脉复杂病变PCI术后再缺血事件的发生率,在一定程度上改善临床预后,且不增加出血风险。     

氯吡格雷中间代谢类型老年ACS患者PCI术后替格瑞洛与氯吡格雷治疗的预后评价

目的:比较替格瑞洛与氯吡格雷在氯吡格雷中间代谢类型老年急性冠状动脉综合征(ACS)患者经皮冠状动脉介入治疗(PCI)术后的预后评价。方法:选取2016-01-2018-06入住我院接受PCI的氯吡格雷基因检测为中间代谢类型的老年ACS患者132例,氯吡格雷组72例,替格瑞洛组60例。替格瑞洛组给予180 mg负荷剂量嚼服后90 mg bid维持1年;氯吡格雷组给予300/600 mg嚼服后75 mg qd维持1年。观察两组治疗前后5 d血小板抑制率和随访12个月内两组患者主要不良心血管事件(MACE)及药物不良反应。结果:治疗后第5天,替格瑞洛组血小板抑制率高于氯吡格雷组(P0.01)。12个月内两组MACE事件差异无统计学意义(P0.05);替格瑞洛组和氯吡格雷组总出血事件分别为10例(16.7%)和3例(4.2%)(P0.05);两组均未发生主要出血;轻微出血为7例(11.7%)和2例(2.8%)(P0.05);呼吸困难分别为例8例(13.3%)和1例(1.4%),差异有统计学意义(P0.01);其中轻度呼吸困难为6例(10.0%)和1例(1.4%)(P0.05)。结论:与氯吡格雷相比替格瑞洛对氯吡格雷中间代谢类型老年ACS患者PCI术后的血小板抑制率更高,12个月内两组MACE事件无显著性差异,氯吡格雷治疗安全有效;替格瑞洛组总出血事件和呼吸困难增加,建议老年ACS患者PCI术后6个月改用替格瑞洛60 mg bid维持治疗。     

替格瑞洛在急诊PCI术中应用的疗效及安全性观察

目的探讨替格瑞洛在急诊经皮冠状动脉介入治疗(PCI)术中应用的疗效及安全性。方法2013年1月至2014年3月在我院诊断为急性心肌梗死并急诊行PCI术的患者共192例,随机分为替格瑞洛组(n=105)和氯吡格雷组(n=87),对两组患者的临床资料进行统计学分析,对比住院期间及随访3月不稳定性心绞痛、心肌梗死、死亡等主要不良心脑血管事件(MACCE)发生率及出血、呼吸困难等不良事件发生率。结果两组的基本情况无统计学差异(P0.05);术后随访3个月发现MACCE事件发生率替格瑞洛组明显低于氯吡格雷组(P0.05),出血发生率两组无统计学差异(P0.05);氯吡格雷组中有6例再发急性冠脉综合征(ACS),均再次行PCI干预,改用替格瑞洛术前负荷剂量180 mg,术后90 mg2/日,分别于术前及后24 h查血栓弹力图,结果显示ADP抑制率及ADP诱导的血小板-纤维蛋白凝块强度(MAADP)应用替格瑞洛后均优于应用替格瑞洛前(P0.05)。结论替格瑞洛较氯吡格雷在我国人群急诊PCI术中具有更好的疗效及安全性。     

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。     

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.     

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.