月见草油复方制剂对实验性动脉粥样硬化家兔血脂及主动脉的影响

本文观察了月见草油复方制剂对兔动脉粥样硬化模型的血脂及主动脉壁病变的影响。复方制剂中含有月见草油中提取的高浓度γ-亚麻酸、当归提取物及穿山龙总皂甙等成份,将此药按每日每千克体重1g一次性喂饲大耳白兔,16周后可明显降低血清总胆固醇(p<0.01)、低密度脂蛋白胆固醇(p<0.05),显著提高血清高密度脂蛋白胆固醇(p<0.01),并抑制主动脉壁平滑肌细胞增生及泡沫细胞形成。提示月见草油复方制剂能抑制动脉粥样硬化斑块的形成。     

食鱼对年轻人主动脉壁的影响和动脉粥样硬化早期病变的研究

用国家“七五”课题方法，对５１例渔区（舟山、宁波）意外死亡年轻人（１５～３９岁）尸检主动脉动脉粥样硬化（ＡＳ）早期病变进行了研究。数据经统计学处理，并与国家“七五”课题资料结果相比较。显示：渔区人主动脉内膜嗜苏丹病变（ＳＬ）面积百分比明显小于南宁，更小于北京；胸主动脉壁蛋白聚糖（ＰＧ）总量渔区低于南宁（Ｐ＜０．０１），硫酸乙酰肝素－蛋白聚糖（ＨＳ－ＰＧ）相对百分含量略高于南宁（Ｐ＞０．０５），亦高于北京（Ｐ＜０．０５）；主动脉内膜平滑肌细胞核数密度渔区大于南宁（Ｐ＜０．０５），面密度小于北京（Ｐ＜０．０５），中膜平滑肌细胞核面密度明显小于南宁及北京（Ｐ＜０．０１）；渔区主动脉ＡＳ病变检出率：Ⅰ、Ⅱ级病变与南宁、北京无差异，Ⅲ、Ⅳ、Ⅴ级病变均明显轻于南宁和北京（Ｐ＜０．０１）。结果提示：多食海鱼的生活习惯是导致鱼区人ＡＳ群的病变程度轻的重要因素之一。     

动脉粥样硬化高、低发区年轻人冠状动脉病变的比较性研究

目的：从流行病病理学的角度，分析和比较动脉粥样硬化（ＡＳ）高发区（北京）、低发区（南宁）及渔区（宁波）年轻人ＡＳ病变检出率及病变特点，并探讨ＡＳ的病变规律，为防治ＡＳ提供依据。方法：收集北京、南宁、宁波等地３０２例意外死亡年轻人（１５～３９岁）新鲜心脏标本的冠状动脉左前降支，苏木素伊红（ＨＥ）、弹力纤维＋ＶａｎＧｉｅｓｏｎ（ＥＴ＋ＶＧ）及苏丹─油红Ｏ染色，经形态学观察将ＡＳ病变分为ＩＶ型。ＡＳ病变检出率比较采用卡方检验。结果：ＡＳ病变检出率随年龄增长而逐渐升高。３０２例左前降支ＡＳ病变总检出率达６８．３％。北京地区ＡＳ病变检出率，尤其是中、晚期病变检出率明显高于南宁及宁波地区并接近受检人群的１／４。北京地区检出斑块的年龄早于南宁及宁波地区，且斑块多显示为动态发展趋势，而南宁、宁波地区斑块多为静止、稳定状态。结论：ＡＳ高、低发区人群冠状动脉粥样硬化病变的发病程度、发展趋势及进展速度均有所不同。我国ＡＳ检出率仍有上升趋势，这一变化应从预防冠状动脉粥样硬化和冠状动脉粥样硬化性心脏病（冠心病）的角度给予高度重视。     

中药顺势三服法治疗颈动脉粥样硬化斑块的安全性及即时和远期效果分析

目的]探讨中药顺势三服法在颈动脉粥样硬化斑块患者中的应用效果。 [方法]选取94例颈动脉粥样硬化斑块患者,随机分成两组,每组47例。对照组采取常规一日一方治疗,观察组采取中药顺势三服法治疗,疗程4个月。观察两组临床疗效、治疗前后中医证候积分、血脂[总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDLC)、低密度脂蛋白胆固醇(LDLC)]、CD40/CD40L炎症信号通路、斑块总积分、颈动脉内膜中膜厚度(IMT)、斑块面积、肝肾功能[谷丙转氨酶(ALT)、谷草转氨酶(AST)、血尿素氮(BUN)、肌酐(Cr)]及不良反应。 [结果]观察组治疗4个月后和停药6个月后总有效率(74.47%、78.72%)高于对照组(46.81%、44.68%,P＜0.05);两组治疗4个月后,ALT、AST、BUN、Cr水平与治疗前比较、两组间比较,差异均无显著性(P＞0.05);观察组不良反应发生率(14.89%)与对照组(10.64%)比较差异无显著性(P＞0.05);观察组停药6个月后,中医证候积分低于对照组(P＜0.05);白细胞介素1(IL-1)、IL-6、可溶性CD40配体(sCD40L)水平低于对照组,IL-10水平高于对照组(P＜0.05);IMT、斑块总积分、斑块面积低于对照组(P＜0.05)。 [结论]相比一日一方的常规服法,采用中药顺势三服法分别于早、中、晚服用桃红四物汤、二陈汤、四妙勇安汤能明显提高即时疗效,更有效改善停药后稳定斑块面积和IMT,且不会明显增加药物不良反应及肝肾毒性。     

早发冠心病患者颈动脉内膜中膜厚度特点及其预测价值

探讨早发冠心病患者颈动脉内膜中膜厚度和斑块特征及其对早发冠心病的预测价值。应用B型超声检测早发冠心病患者颈动脉内膜中膜厚度和斑块情况 ,结合冠状动脉造影结果进行对比研究。结果发现 ,早发冠心病患者颈动脉内膜中膜厚度≥ 0 .8mm及斑块检出率明显高于对照组 (5 6 %比 11% ,P <0 .0 5 ) ;颈动脉超声阳性对预测早发冠心病的敏感性为 5 5 .7% ,特异性为 88.9% ,准确性为 87.2 % ;3支冠状动脉病变组平均内膜中膜厚度高于 1支冠状动脉病变组。多因素分析发现 ,颈动脉超声阳性是早发冠心病的独立危险因素 (OR =7.19,95 %CI:1.92～ 2 1.37,P =0 .0 0 7)。结果提示 ,早发冠心病患者颈动脉内膜中膜厚度增厚及斑块检出率升高 ,颈动脉超声阳性对诊断早发冠心病有着较高的特异性和准确性。     

北京地区年青人冠状动脉粥样硬化的研究

收集北京地区１００例意外死亡年青人（１５￣３９岁）新鲜心脏标本的冠状动脉，对其动脉粥样硬化病变检出率及病变特点进行观察。结果为：部分脂纹有可能通过中间型病变转变为斑块；年青人动脉粥样硬化斑块多以细胞性纤维组织增生为主；动脉粥样硬化病变总检出率为５６．０％，男性病变检出率高于女性，且随年龄增长而增高。冠状动脉狭窄检出率与斑块检出率呈正相关。结果表明北京地区年青人冠状动脉粥样硬化病变检出率特别是由斑块     

急性冠状动脉综合征患者血清中性粒细胞百分比与白蛋白比值与冠状动脉分层斑块的相关性

目的]研究血清中性粒细胞百分比与白蛋白比值(NPAR)水平与急性冠状动脉综合征(ACS)患者冠状动脉分层斑块的相关性。 [方法]选取2018年1月─2023年1月于新疆医科大学第一附属医院心脏中心行冠状动脉造影(CAG)和造影后即刻对罪犯血管行光学相干断层成像(OCT)检查并确诊为ACS的患者222例作为研究对象,根据图像结果分为分层斑块组111例和非分层斑块组111例。比较分层斑块组和非分层斑块组血清NPAR水平,采用多因素Logistic回归分析法分析冠状动脉分层斑块的影响因素。 [结果]与非分层斑块组比较,分层斑块组的饮酒史、管腔狭窄率、中性粒细胞百分比水平、NPAR水平高于非分层斑块组,白蛋白水平低于非分层斑块组,差异均有统计学意义(P＜0.05)。OCT特性比较,分层斑块组脂质弧更大、纤维帽厚度更薄、巨噬细胞浸润率更高、易损斑块、斑块破裂、胆固醇结晶、滋养血管、血栓、钙化小结、钙化斑块检出率更高,纤维斑块检出率更低,差异均有统计学意义(P＜0.05)。Spearman相关分析显示,血清NPAR与斑块破裂、薄纤维帽粥样斑块(TCFA)表现为正相关(r＝0.436、r＝0.622,均P＜0.05)。多因素Logistic回归分析显示,高水平的NPAR是ACS患者罪犯血管发生分层斑块的独立危险因素(OR＝10.186,95%CI:3.242～31.999,P＜0.001)。 [结论]分层斑块与斑块不稳定特性相关,血清NPAR水平在ACS罪犯血管分层斑块患者中升高,是ACS患者冠状动脉分层斑块的独立危险因素。     

冠状动脉计算机断层扫描血管造影对老年急性冠状动脉综合征患者斑块特征的诊断效能及对预后的预测价值

目的 探讨冠状动脉计算机断层扫描血管造影(CCTA)对老年急性冠状动脉综合征(ACS)患者斑块特征的诊断效能及对预后的预测价值。方法 回顾性分析2021年2月至2022年12月海南省琼海市人民医院胸痛中心收治的疑似冠心病的208例老年患者的临床资料,其中58例发生ACS,纳入ACS组。根据ACS组患者性别、年龄及心血管危险因素(吸烟史、高血压、糖尿病、血脂水平等),采用倾向评分匹配法(比例1∶1)同期选择58例发生稳定型心绞痛(SAP)的患者纳入SAP组。所有患者均行CCTA检查,比较两组患者斑块长度、钙化斑块(CP)体积、非钙化斑块(NCP)体积、总斑块体积、CP负荷、NCP负荷和总斑块负荷等斑块特征参数。此外,根据预后将58例ACS组患者分为不良心血管事件(MACEs)组(n=15)和非MACEs组(n=43),比较不同预后患者CCTA斑块特征参数。采用SPSS 22.0统计软件进行数据分析。根据数据类型,分别采用t检验或χ²检验进行组间比较。采用Pearson相关分析血脂水平与斑块特征参数的相关性。采用受试者工作特征曲线(ROC)分析斑块特征参数对ACS及MACEs的预测价值。结果 ACS组患者斑块长度、NCP体积和NCP负荷均显著高于SAP组,差异有统计学意义(P<0.05)。MACEs组患者斑块长度、NCP体积和NCP负荷均显著高于非MACEs组,差异有统计学意义(P<0.05)。Pearson相关性分析结果显示,血清低密度脂蛋白胆固醇(LDL-C)与斑块长度、CP体积、NCP体积、总斑块体积、CP负荷、NCP负荷及总斑块负荷呈正相关(r=0.463,0.246,0.414,0.292,0.251,0.392,0.215;P<0.05)。ROC曲线分析结果显示,斑块长度、NCP体积、NCP负荷对ACS有较好的预测价值,曲线下面积(AUC)分别为0.843(95%CI 0.761~0.925)、0.814(95%CI 0.703~0.926)和0.721(95%CI 0.573~0.869);发生ACS的最佳截断值分别为19.19mm、152.99mm³和42.56%;灵敏度分别为91.67%、91.67%和66.67%;特异度分别为75.00%、63.54%和77.08%。斑块长度、NCP体积、NCP负荷对MACEs有较好的预测价值,AUC分别为0.694(95%CI 0.515~0.876)、0.711(95%CI 0.502~0.920)和0.735(95%CI 0.551~0.919);发生MACEs的最佳截断值分别为21.02mm、169.62mm³和45.37%;灵敏度分别为77.78%、66.67%和88.89%;特异度分别为59.18%、85.71%和61.22%(P＜0.05)。结论 基于CCTA的斑块特征参数不仅对老年ACS有较好的鉴别作用,还可有效预测ACS患者1年内MACEs的发生。     

柚皮素通过调控平滑肌细胞TIMP-3表达促进动脉粥样硬化斑块稳定

目的]探究柚皮素对动脉粥样硬化斑块胞外基质重构和斑块稳定性的影响。 [方法]分离原代小鼠血管平滑肌细胞,进行不同剂量的柚皮素处理。对高脂诱导的ApoE－/－小鼠进行柚皮素灌胃16周,天狼星红-苏木精染色分析主动脉根部斑块坏死核面积、斑块内胶原含量和纤维帽厚度,Van Gieson染色检测弹力蛋白降解,明胶酶谱法和荧光标记明胶法检测斑块内基质金属蛋白酶(MMP)活性。 [结果]柚皮素(50 μmol/L)促进平滑肌细胞信号转导及转录活化因子6(STAT6)磷酸化和组织型基质金属蛋白酶抑制剂3(TIMP-3)的转录活性,TIMP-3的表达升高3.1倍(P＜0.001)。柚皮素(80 mg/kg)处理后,与对照组相比,主动脉根部斑块坏死核面积降低53%(P＜0.01)、纤维帽厚度提高近50%(P＜0.05),弹力纤维降解程度降低。同时,柚皮素促进斑块内TIMP-3的表达,斑块内MMP活性也相应降低。慢病毒介导的体内抑制TIMP-3表达可降低柚皮素对斑块稳定的保护作用。 [结论]柚皮素通过提高平滑肌细胞内TIMP-3表达,改善细胞外基质成分,促进动脉粥样硬化斑块稳定。     

脂源性激素促酰化蛋白在冠心病患者中的变化及意义

为探讨冠心病患者血浆中脂源性激素促酰化蛋白浓度的变化,并进一步研究促酰化蛋白与冠心病患者血脂变化的相关性,收集冠心病患者62例,正常健康者47例,记录临床资料,包括身高、体重、性别、年龄和血压,采用酶联免疫吸附法检测血浆促酰化蛋白浓度,并用酶法检测总胆固醇、甘油三酯、低密度脂蛋白、高密度脂蛋白、载脂蛋白Al和载脂蛋白B₁₀₀水平。结果发现,冠心病患者促酰化蛋白浓度明显高于正常对照组,差异有显著性(p<0.05)。冠心病组体重指数、血压及血浆总胆固醇、甘油三酯、低密度脂蛋白、高密度脂蛋白及载脂蛋白B₁₀₀水平与正常对照组相比均存在显著性差异(p<0.05)。冠心病患者血浆促酰化蛋白与体重指数、总胆固醇、甘油三酯、低密度脂蛋白、载脂蛋白B₁₀₀呈显著正相关(分别为r=0.42,p<0.01;r=0.36,p<0.01;r=0.20,p<0.05;r=0.31,p<0.05;r=0.45,p<0.01)。结果提示,促酰化蛋白参与了冠心病患者脂质代谢紊乱的发生,血浆促酰化蛋白水平可作为评估冠心病发病危险因素的一项新指标。     

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.