代谢综合征组分与结直肠腺瘤性息肉复发关系的研究

背景：研究显示一些代谢综合征（MS）组分为结直肠腺瘤性息肉的危险因素,然而关注MS组分在结直肠腺瘤性息肉复发中意义的研究尚少。目的：研究MS组分与结直肠腺瘤性息肉复发的关系。方法：纳入2003年1月～2009年1月于北京大学人民医院行内镜下结直肠息肉切除术、病理诊断为腺瘤性息肉并有2年以上复查资料的成年患者,采集其包括4项MS组分（肥胖、高血压、高血糖、血脂异常）在内的12项可疑危险因素,筛选复发相关因素,以之为自变量,以研究起点之后第1～3年期间的结肠镜复查结果为因变量,行多元logistic回归分析,计算OR值并换算为RR值。结果：共138例患者纳入研究,76例（55.1%）在研究起点之后第1～3年期间复发,4例复查时发现结直肠癌年龄、高血压病史、糖尿病病史、饮酒史和多发性腺瘤以及伴发MS组分的数量与复发相关（P〈0.05）。logistic回归分析显示MS组分（OR=2.308,P〈0.01：RR=1.342）和年龄（OR=1.040,P〈0.05;RR=1.018）为复发的独立危险因素。结论：伴发MS组分的结直肠腺瘤性息肉更易复发,提示可将MS组分纳入结直肠腺瘤性息肉治疗后复查的参考指标。     

上消化道腺瘤与结直肠肿瘤相关性的病例对照研究

目的 评估上消化道腺瘤患者中结直肠肿瘤(腺瘤和癌)的患病情况.方法 回顾性分析2007年至2011年消化内镜检查的患者,选取经病理证实为上消化道腺瘤并且行结肠镜检查的39例作为病例组,选取同期行胃肠镜检查而胃镜示无腺瘤并且性别年龄匹配的78例作为对照组,比较两组结直肠肿瘤患病情况的差异.结果 病例组结直肠肿瘤的检出率为51.3％ (20/39),其中腺瘤的检出率为38.5％(15/39),癌的检出率为12.8％(5/39).对照组中结直肠肿瘤的检出率为14.1％(11/78),其中腺瘤的检出率为12.8％(10/78),癌的检出率为1.3％(1/78).病例组结直肠肿瘤的检出率明显高于对照组(P ＜0.001),其中结肠腺瘤和结肠癌的检出率也均分别高于对照组(50.0％比12.5％和52.2％比15.2％).分别将胃、十二指肠腺瘤进行单独比较,亦发现两组结直肠肿瘤检出率均显著高于相应对照组.结论 上消化道腺瘤的患者结直肠肿瘤的检出率较高,建议及时行结肠镜检查.     

胃底腺息肉与结直肠肿瘤相关性

目的探讨胃底腺息肉(fundic gland polyps,FGPs)与结直肠肿瘤的相关性.方法回顾性收集2013-05/2016-05所有在吉林大学第一医院同期行胃镜及肠镜检查的患者病历资料,分为FGPs组(243例)和对照组(486例).使用SPSS17.0软件进行统计分析,探讨FGPs和结直肠肿瘤的相关性.结果F G P s组结直肠肿瘤检出率高于对照组[19.8%(48/243)vs 8.8%(43/486)],其中结直肠癌的检出率差异无统计学意义(P=0.67),而结直肠腺瘤的检出率差异有统计学意义(P0.001).通过对年龄、性别进行分层分析得出,女性及≥50岁的FGPs患者的结直肠肿瘤检出率明显高于对照组(P0.001,0.001).进一步就不同部位的结直肠肿瘤分层分析显示,FGPs合并结直肠肿瘤的患者中,女性及≥50岁的,无论是在近端结肠还是远端结直肠,结直肠肿瘤检出率均高于对照组(P0.05).结论患有FGPs尤其是女性及≥50岁的患者,合并近端结肠及远端结直肠肿瘤的风险增高,应尽早行肠镜检查.     

对冠状动脉造影者行结直肠肿瘤高危人群分层研究

目的 对行冠状动脉造影(CAG)检查者,比较亚太地区结直肠筛选评分系统(APCS评分)和中国卫生部结直肠癌序贯筛查方案(卫生部标准)评判结直肠肿瘤高度危险人群的差异.方法 分别采用APCS评分和卫生部标准对870例40～74岁接受CAG检查的患者资料进行回顾性分析.计量资料采用t检验,计数资料采用x2检验.结果 40～＜50岁患者共72例,按卫生部标准筛选出高度危险患者8例,按APCS评分无高度危险人群.50～74岁患者共798例,按APCS评分筛选出高度危险患者460例;CAG阴性组比例(34.7％)显著低于冠状动脉疾病(CAD)组(68.0％,x2=77.74,P＜0.01).按卫生部标准筛选出高度危险患者134例,CAG阴性组比例(17.7％)与CAD组(16.4％)间差异无统计学意义(P＞0.05).在50～74岁无一级亲属结直肠癌家族史的患者中,CAG阴性组有72例(29.0％)、CAD组有316例(57.5％)按APCS评分为高度危险,而按卫生部标准为非高度危险人群,其中男性吸烟者占90.5％ (351/388);CAG阴性组有30例(12.1％)、CAD组有32例(5.8％)患者按APCS评分为中度危险,而按卫生部标准为高度危险人群,其中不吸烟的女性患者占75.8％(47/62).结论 由APCS评分筛查出结直肠肿瘤高度危险患者的比例高于卫生部标准.对50～74岁、无一级亲属结直肠癌家族史的患者,APCS评分可能高估了男性吸烟者发生结直肠肿瘤的危险度,低估了不吸烟的女性患者的危险度.     

转化生长因子-β1及肿瘤坏死因子相关凋亡诱导配体基因多态性与结节性甲状腺疾病相关性研究

目的 探讨转化生长因子(TGF)-β1 +869T/C和肿瘤坏死因子相关凋亡诱导配体(TRAIL)+1525 G/A的基因多态性在结节性甲状腺疾病患者中的分布及其相关性.方法 选择2007年9月至2009年9月于内蒙古科技大学包头医学院第一附属医院内分泌科确诊的结节性甲状腺疾病患者544例作为研究对象,其中包括136例结节性甲状腺肿患者(结甲组),132例甲状腺瘤患者(腺瘤组),146例Graves病患者(GD组),130例桥本甲状腺炎患者(HT组),同时另选择135例健康体检者作为对照组.所有对象清晨空腹采2ml静脉血,采用聚合酶链式反应-单链构象多态分析(PCR-SSCP)、聚合酶链式反应-限制性内切酶片段长度多态性(PCR-RFLP)技术检测TGF-β1+869 T/C和TRAIL+ 1525A/G基因多态性.结果 ①TGF-β1+869T/C:结甲组的CC基因型[47.0％ (64/136)]、C等位基因频率[63.2％(172/272)]均高于对照组[16.3％(22/135)、45.2％(122/270)],组间比较差异有统计学意义(x2=30.76、17.79,P均＜0.05).腺瘤组CC基因型[42.4％(56/132)]、C等位基因频率[59.1％(156/264)]均高于对照组,组间比较差异有统计学意义(x2=24.40、10.34,P均＜0.05).携带C等位基因的人群患结节性甲状腺肿的风险是携带T等位基因的2.086倍[比值比(OR)=2.086;95％可信区间(CI):1.480～2.943];携带C等位基因的人群患腺瘤的风险是携带T等位基因的1.752倍(OR=1.752;95％CI:1.244～2.469).②TRAIL+1525G/A:结甲组GG基因型[40.4％(55/136)]、G等位基因频率[62.9％(171/272)]均高于对照组[11.9％(16/135)、48.5％(131/270)],组间比较差异有统计学意义(x2=9.176、11.307,P均＜0.05).腺瘤组GG基因型[53.0％(70/132)]及等位基因频率[73.1％(193/264)]均高于对照组,组间比较差异有统计学意义(x2=9.806、33.82,P均＜0.05).携带G等位基因的人群患结节性甲状腺肿的风险是携带A等位基因的1.796倍(OR=1.796,95％CI:1.275～ 2.531);携带G等位基因的人群患腺瘤的风险是携带A等位基因的2.884倍(OR=2.884,95％CI:2.009 ～ 4.142).结论 TGF-β1+869T/C、TRAIL+1525G/A多态性可能与结节性甲状腺疾病的发病有关,TGF-β1的C等位基因和TRAIL的G等位基因可能是结节甲状腺疾病的易感基因.     

腹腔镜联合快速康复结直肠外科手术在老年人结直肠癌治疗中的近期疗效分析

目的 评估70岁以上老年结直肠癌患者接受腹腔镜联合快速康复结直肠外科(FTCS)治疗的安全性、可行性. 方法 将123例老年结直肠癌患者,随机分为腹腔镜+ FTCS组(41例)、腹腔镜组(41例)和开腹组(41例).比较患者手术效果指标,康复指标以及术后并发症等. 结果 腹腔镜+FTCS组与单独腔镜组或开腹组比较,其失血量、手术时间、排便时间,淋巴结清扫个数等差异无统计学意义(P＞0.05);腹腔镜+FTCS组较腔镜组或开腹组能够显著缩短患者下床时间、排气时间、首次流质时间以及住院时间(P＜0.05).各组术后并发症发生率分别为腹腔镜+ FTCS组:12.2％(5/41);腹腔镜组:34.1％(14/41);开腹组:68.3％(28/41).腹腔镜+FTCS组患者并发症发生率低于腹腔镜组和开腹组(x2 =5.549,P=0.018;x2 =28.826,P＜0.01),腹腔镜组患者并发症发生率显著低于开腹组(x2 =9.567,P=0.002). 结论 腹腔镜联合FTCS治疗方法在老年结直肠癌治疗中安全有效,是老年结直肠癌患者的理想治疗方式.     

孤立性脑桥梗死的临床和影像学特征:脑桥旁正中梗死与脑桥腔隙性梗死的比较

目的 探讨孤立性脑桥梗死的临床和影像学特征以及早期运动障碍进展(progessive motor deficits,PMD)和短期预后的影响因素.方法 对初次发病24 h内入院的86例孤立性脑桥梗死患者进行回顾性分析,根据梗死灶最大直径和部位分为脑桥旁正中梗死(paramedian pontine infarction,PPI)和脑桥腔隙性梗死(lacunar pontine infarction,LPI),根据早期PMD情况分为PMD组和无PMD组,根据出院时改良Rankin量表(modified Rankin Scale,mRS)评分分为转归不良组(mRS评分＞2分)和转归良好组(mRS评分≤2分),对不同病例组的临床和影像学特征进行比较.结果 PPI组(n=35)高脂血症(57.14％对33.33％;x2=4.80,P=0.028)、偏瘫(97.14％对72.55％;x2=8.718,P=0.003)、基底动脉狭窄(45.71％对17.65％;x2=7.930,P=0.005)和出院时转归不良(54.29％对31.37％;x2=4.515,P=0.034)患者构成比以及基线美国国立卫生研究院卒中量表(National Institutes of Health Stroke Scale,NIHSS)评分[(6.00 ±2.39)分对(4.61 ±3.41)分;t=2.087,P=0.040]均显著性高于LPI组(n＝ 51).PMD组(n=22)基线舒张压水平[(97.82±15.61)mm Hg对(89.55±12.23)mm Hg,1 mm Hg=0.133 kPa;t =2.258,P=0.031]以及PPI(63.64％对32.81％;x2=6.445,P＝0.011)和基底动脉狭窄(59.10％对18.75％;x2=12.922,P=0.000)的构成比均显著性高于无PMD组(n＝64).转归不良组(n＝ 35)基线NIHSS评分[(6.80±2.63)分对(3.73 ±2.55)分;t＝5.426,P＝0.000]和空腹血糖水平[(9.40±5.15) mmol/L对(6.56 ±2.69) mmol/L;t =2.985,P=0.004]以及PPI患者构成比(54.29％对31.37％;x2 =4.515,P＝0.034)均显著性高于转归良好组(n=51).多变量logistic回归分析显示,基底动脉狭窄是PPI发病[优势比(odds ratio,OR)3.801,95％可信区间(confidence interval,CI)1.357～10.646;P=0.011]和孤立性脑桥梗死早期PMD(OR 4.571,95％ CI1.214～17.214;P=0.025)的独立危险因素,基线NIHSS评分≥5分是其短期转归不良的独立预测因素(OR4.277,95％ CI 1.505 ～ 12.151;P=0.006).结论 PPI主要与基底动脉分支病变有关,基线NIHSS评分≥5分可能是孤立性脑桥梗死短期转归不良的独立预测因素,其早期PMD和短期转归不良均可能与基底动脉病变有关.     

Barrett食管与结直肠息肉的相关性

目的:探讨Barrett食管与结直肠息肉的相关性.方法:收集Barrett食管组41例,对照组176例,比较两组中结直肠息肉的发生率,息肉的病理类型及息肉发生部位.结果:Barrett食管组中息肉发生率为41.5%,高于对照组的25.6%,二组之间差异有统计学意义(P=0.042).两组中炎性息肉及增生性息肉的发生率差异无统计学意义(P=0.32,P=0.18).但Barrett食管组中腺瘤性息肉发生率显著高于对照组(P=0.008).两组中息肉发生部位无明显差异.多因素Logistic回归分析显示Barrett食管是结直肠息肉的独立相关因素(OR=2.397,95%CI:1.146-5.013,P=0.020).结论:Barrett食管与结直肠息肉发生相关,对Barrett食管患者应重视结直肠息肉筛查和监视.     

军队老年人良性前列腺增生的患病率与代谢综合征的关系

目的 研究老年人良性前列腺增生(BPH)的患病率及其与代谢综合征(MS)的关系.方法 对石家庄26个部队休干所的1230例70岁及以上的离退休干部进行BPH及MS的患病率调查.结果 老年男性BPH的患病率为77.0％,随着年龄的增长,BPH的患病率有增高的趋势(x2=50.4,P＜0.01);老年男性MS的患病率为19.6％ ;MS是BPH发生的危险因素(x2=24.2,P＜0.01).结论 MS可能是BPH发生的危险因素之一.     

血脂水平与结直肠息肉发病的关系

目的：探讨血脂水平与结直肠息肉发病的关系。方法选择结直肠息肉患者218例（病例组）、非结肠息肉患者164例（对照组）,利用全自动生化分析仪检测两组血清TC、TG、LDL-C和HDL-C,并分析血脂水平、年龄、性别、病理类型等因素与结直肠息肉发病的关系。结果病例组高脂血症患病率为43．1％,显著高于对照组的15．2％（P＜0．05）,且不同病理类型结直肠息肉患者高脂血症患病率均高于对照组（P均＜0．05）。病例组男性高脂血症患病率为48．9％,显著高于女性的33．7％（P＜0．05）;病变位于左半结肠及直肠患者高脂血症患病率为46．6％,显著高于右半结肠的27．6％（P＜0．05）。 Spearman直线相关分析显示,结直肠息肉的发病与患者年龄及血清TC、TG呈直线相关（r分别为0．826、0．713、0．635,P均＜0．05）。结论血脂水平与结直肠息肉的发病密切相关,高脂血症是导致结直肠息肉的高危因素。     

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.