福辛普利和氯沙坦对SHR血管紧张素Ⅱ受体1基因表达的影响

目的研究福辛普利和氯沙坦对自发性高血压大鼠(SHR)血管紧张素Ⅱ受体1(AT1-R)的基因表达水平及心血管细胞增殖的影响,探讨高血压病的病理机制.方法 48只10周龄SHR随机分3组,1组服福辛普利5 mg*kg-1*d-1;2组服氯沙坦20 mg*kg-1*d-1;3组(对照组) 服安慰剂.3组分别灌胃持续9 周,实验前及实验中每2周测尾动脉血压,9周后,抽血并处死动物取材,放免法测血管紧张素Ⅱ(Ang Ⅱ),用半定量RT-PCR 测量心肌AT1-R的 mRNA水平,光、电镜观察心肌及主动脉组织学改变. 结果血压对照组随增龄上升,两治疗组实验第2周起各次均较治疗前低,差异多具显著性,实验第8周福辛普利组为(165.1±4.9)mmHg、氯沙坦组为(156.3±4.2)mmHg,均较对照组(179.1±10.4)mmHg低,差异显著,P<0.01.血浆Ang Ⅱ浓度对照组为(440.0±190.3)pg/mL,福辛普利组为(566.0±149.3)pg/mL和氯沙坦组(529.3±200.9)pg/mL均较对照组高,但均无显著性差异,P>0.05.心肌AT1-R的mRNA水平福辛普利组为(72.0±35.0)%,对照组为(102.4±21.9)%,显著高于前者,P<0.05;氯沙坦组为(101.9±27.3)%,与对照组差异无显著性,P>0.05,但较福辛普利组高,差异显著,P<0.05;AT1-R的mRNA水平与治疗后血压不相关,与对照组Ang Ⅱ浓度正相关,r=0.596,P<0.05,而与两治疗组无相关性;心血管病变光、电镜下两治疗组心血管细胞增殖明显减轻,氯沙坦组减轻更显著. 结论福辛普利可下调SHR心肌AT1-R基因表达水平,氯沙坦则对其无影响;福辛普利和氯沙坦均可抑制SHR心血管细胞增殖,但不伴有Ang Ⅱ浓度的显著性改变.     

高脂血症患者LDL氧化易感性及调脂药物干预的影响

目的观察高脂血症对LDL氧化易感性的影响以及调脂药物干预后的改变.方法应用短程密度梯度超速离心分离血浆LDL,对11例高甘油三酯血症患者口服微粒化非诺贝特200 mg/d、10例高胆固醇血症患者口服普伐他汀10 mg/d治疗4周前后和6例正常人的LDL在体外以CuCl2诱导氧化,测定LDL开始氧化的迟滞期和氧化速率.结果 (1)LDL氧化的迟滞期,在高甘油三酯血症患者和高胆固醇血症患者均较正常组明显缩短(43.8±11.6,40.8±10.7 vs 70.5±14.6 min, P均<0.01).(2)LDL的氧化速率,在高甘油三酯血症患者和高胆固醇血症患者均较正常组明显增快(0.036±0.004,0.031±0.011 vs 0.020±0.011 O.D./min,P均<0.05).(3)高甘油三酯血症患者给微粒化非诺贝特治疗后LDL氧化的迟滞期显著延长(62.4±5.0 min,P<0.01),氧化速率明显减慢(0.031±0.003 O.D./min,P<0.05).(4)高胆固醇血症患者于普伐他汀治疗后LDL氧化的迟滞期明显延长(58.8±6.1 min,P<0.05),氧化速率无显著性变化(0.025±0.009 O.D./min,P>0.05).结论高甘油三酯血症患者和高胆固醇血症患者LDL氧化易感性增高,微粒化非诺贝特和普伐他汀能够降低高甘油三酯血症患者及高胆固醇血症患者LDL的氧化易感性.     

福辛普利对原发性高血压患者降压作用和对内皮功能的影响

目的评价福辛普利对轻、中度原发性高血压患者的降压疗效,以及对原发性高血压患者内皮功能和肾素-血管紧张素系统(RAS)影响的机制.方法60例原发性高血压患者,随机分为福辛普利组30例和吲哒帕胺组30例.观察治疗前与治疗后6周,诊所血压(CBP)、血浆一氧化氮、内皮素、肾素活性、血管紧张素Ⅱ和醛固酮浓度变化,并对CBP和RAS、血压水平与内皮功能之间的相关性进行分析.结果治疗后2组血压水平显著下降,福辛普利组收缩压从160士14mmHg降至149±13mmHg,舒张压从96±7mmHg降至84±6mmHg,吲哒帕胺组收缩压从161±16mmHg降至154±14mmHg,舒张压从94±6mmHg降至85±7mmHg,差异有极显著性(P均＜0.001).福辛普利组血浆一氧化氮升高,肾素活性上升,内皮素下降,血管紧张素Ⅱ下降,醛固酮下降,差异有极显著性(P均＜0.001),吲哒帕胺组上述参数未见明显变化(P均＞0.05).结论福辛普利对于轻、中度原发性高血压患者疗效显著,福辛普利降压同时能改善动脉内皮功能,降低RAS活性.     

福辛普利和氯沙坦对SHR血管紧张素Ⅱ受体1基因表达的影响

目的　研究福辛普利和氯沙坦对自发性高血压大鼠 (SHR)血管紧张素Ⅱ受体 1(AT1 R)的基因表达水平及心血管细胞增殖的影响 ,探讨高血压病的病理机制。方法　 48只 10周龄SHR随机分 3组 ,1组 :服福辛普利 5mg·kg-1·d-1;2组 :服氯沙坦 2 0mg·kg-1·d-1;3组 (对照组 ) :服安慰剂。 3组分别灌胃持续 9周 ,实验前及实验中每 2周测尾动脉血压 ,9周后 ,抽血并处死动物取材 ,放免法测血管紧张素Ⅱ (AngⅡ ) ,用半定量RT PCR测量心肌AT1 R的mRNA水平 ,光、电镜观察心肌及主动脉组织学改变。　结果　血压 :对照组随增龄上升 ,两治疗组实验第 2周起各次均较治疗前低 ,差异多具显著性 ,实验第 8周福辛普利组为 (16 5 .1± 4 9)mmHg、氯沙坦组为 (15 6 3± 4 2 )mmHg ,均较对照组 (179 1± 10 4 )mmHg低 ,差异显著 ,P <0 0 1。血浆AngⅡ浓度 :对照组为 (4 40 0± 190 3) pg/mL ,福辛普利组为 (5 6 6 0± 149 3) pg/mL和氯沙坦组 (5 2 9 3± 2 0 0 9)pg/mL均较对照组高 ,但均无显著性差异 ,P >0 0 5。心肌AT1 R的mRNA水平 :福辛普利组为 (72 0± 35 0 ) %,对照组为 (10 2 4± 2 1 9) %,显著高于前者 ,P <0 0 5 ;氯沙坦组为 (10 1 9± 2 7 3) %,与对照组差异无显著性 ,P >0 0 5 ,但较福辛普利组高 ,差异     

辛伐他汀对高血压大鼠主动脉血凝素样氧化低密度脂蛋白受体1表达的影响

目的研究他汀类药物对自发性高血压大鼠主动脉血凝素样氧化低密度脂蛋白受体1 (LOX-1)表达的影响,以了解血凝素样氧化低密度脂蛋白受体1在高血压病血管中的表达及探讨他汀类药物在高血压病中预防动脉粥样硬化的可能作用.方法 20只12周龄雄性自发性高血压大鼠随机分为SHR组(n=10)和辛伐他汀组(n=10),辛伐他汀组每只大鼠予以辛伐他汀5 mg/kg*d灌胃,给药时间8周,同时取10只12周龄雄性京都种Wistar大鼠作为WKY组,利用免疫组织化学和逆转录聚合酶链反应检测各组动物主动脉LOX-1的表达.结果与WKY组比较,SHR组LOX-1表达显著增加(0.12±0.05 vs 0.86±0.11,P<0.05),与SHR组比较,辛伐他汀组经8周治疗后,LOX-1表达显著降低(0.86±0.11 vs 0.54±0.13,P<0.05),SHR组及辛伐他汀组之间血压及血清总胆固醇、总甘油三酯、低密度脂蛋白胆固醇水平无明显差异(P>0.05). 结论高血压大鼠主动脉内皮层LOX-1 表达增加,辛伐他汀对高血压大鼠主动脉内皮层LOX-1 的表达具有抑制作用,此种作用可能是他汀类药物独立于降脂外抗动脉粥样硬化新的机制.     

胰岛素抵抗与脂蛋白(α)水平

本研究以酶联免疫法对照观察了糖尿病患者胰岛素抵抗和非抵抗组的脂蛋白(α)及其他代谢指标.结果显示两组的空腹血糖(FPG)、糖化血红蛋白(HbA1c)和高密度脂蛋白胆固醇(HDL-C)无显著差异(P>0.05),而组间脂蛋白(α)[Lp(α)](228±110;128±108;P<0.01)、总胆固醇(TC)(5.912±0.987;2.022±1.626;P<0.05)、低密度脂蛋白胆固醇(LDL-C)(4.329±1.223;3.482±1.116;P<0.05)有显著差异,特别是脂蛋白(α)值,胰岛素抵抗组较非抵抗组显著升高(P<0.01).结论在Ⅱ型糖尿病患者中,胰岛素抵抗可能是导致脂代谢紊乱,尤其是脂蛋白(α)升高的主要因素之一.     

不同剂量卡托普利对动脉粥样硬化影响的实验研究

目的探讨不同剂量卡托普利对动脉粥样硬化的影响.方法将纯种日本大耳白兔随机分为对照组、胆固醇组、卡托普利高剂量组、中剂量组及低剂量组.建立家兔动脉粥样硬化模型观察各组家兔血脂水平及主动脉的病理学改变;采用原位逆转录PCR法测定各组原癌基因c-myc和c-fos mRNA的表达水平.结果 (1)与胆固醇组比较,卡托普利各剂量组的血脂水平无显著性差异,但病理形态学发现,高剂量组的主动脉斑块面积比明显降低(P<0.05, P<0.01),泡沫细胞层明显减少,低剂量组与胆固醇组比较无显著性差异.(2) 胆固醇组的原癌基因c-myc、c-fos mRNA表达的阳性率较对照组显著增高,而高剂量组的阳性率则显著低于胆固醇组(P<0.05),中、低剂量组与胆固醇组比较无显著差异.结论只有用高剂量的卡托普利才能有效地防止动脉粥样硬化斑块的形成及阻止动脉粥样硬化的发展.     

转化生长因子β1在糖尿病大鼠心肌中的表达及福辛普利的干预

目的研究转化生长因子β1(TGF-β1)在糖尿病大鼠心肌中的表达及福辛普利(Fosinopril)的干预作用. 方法大鼠20只建立糖尿病模型后,随机分为福辛普利治疗组及糖尿病未治疗组,每组10只,用免疫组织化学法检测糖尿病大鼠心肌TGF-β1的表达及用福辛普利治疗后的变化,并与正常组对照. 结果正常组心肌细胞胞浆内,TGF-β1表达呈弱阳性反应;糖尿病未治疗组呈强阳性反应;福辛普利治疗组呈阳性反应.用图像分析仪计算其平均吸光度A值分别为0.009±0.004、0.198±0.007及0.104±0.005.未治疗组TGF-β1的表达明显高于正常组及治疗组(P<0.01). 结论 TGF-β1在糖尿病大鼠心肌中的表达明显增强,而福辛普利能在一定程度上抑制其表达从而可能延缓糖尿病性心肌病的病理学进展.     

三种大鼠动脉粥样硬化模型复制方法的比较

为研究动脉粥样硬化的发病机制,比较了三种大鼠动脉粥样硬化斑块模型建立的方法.分别予单纯高脂、高脂+维生素D、高脂+维生素D+内皮损伤三种不同方法处理大鼠,90天后比较血脂、血钙、胸主动脉的形态学改变、巨噬细胞和α-平滑肌肌动蛋白含量.结果发现,三组实验组与正常对照组相比,总胆固醇、甘油三酯和低密度脂蛋白胆固醇均明显升高(P<0.01);高脂+维生素D组、高脂+维生素D+内皮损伤组与正常对照组和高脂组相比,血钙均明显升高(P<0.01);高脂+维生素D组、高脂+维生素D+内皮损伤与正常对照组相比,内膜增厚、中膜萎缩(P<0.05或P<0.01);单纯高脂组、高脂+维生素D组CD68为弱阳性,高脂+维生素D+内皮损伤组为强阳性;高脂+维生素D组内膜有较厚的α-平滑肌肌动蛋白阳性,高脂+维生素D+内皮损伤组斑块表面只有很薄的α-平滑肌肌动蛋白阳性;单纯高脂组只可形成高脂血症,无法形成动脉粥样硬化病变;高脂+维生素D组可形成纤维斑块;高脂+维生素D+内皮损伤组可形成较成熟的动脉粥样硬化斑块.证明了大鼠可作为研究动脉粥样硬化的良好动物模型,高脂+维生素D+内皮损伤组可形成较成熟的动脉粥样硬化斑块.     

辛伐他汀与福辛普利对慢性心力衰竭大鼠心肌结缔组织生长因子的影响

目的探讨辛伐他汀和福辛普利单用及联合应用对慢性心力衰竭大鼠左心室心肌结缔组织生长因子(connectivetissue growth factor,CTGF)的影响。方法利用肾上腹主动脉缩窄法制作慢性心力衰竭模型,雄性Wistar大鼠50只随机分为假手术组、模型组、辛伐他汀组、福辛普利组、联合用药组(辛伐他汀+福辛普利),每组10只。观察各组大鼠左心室重量指数(LVMI)、左心室舒张末压(LVEDP)、左心室压力最大上升及下降速率(±dp/dt_(max));SP法检测各组大鼠左心室心肌CTGF表达,Western blot检测各组大鼠左心室心肌CTGF蛋白表达水平,RT-PCR测定各组大鼠左心室心肌CTGF mRNA水平。结果与假手术组比较,模型组LVEDP、LVMI明显升高,±dp/dt_(max)明显下降,左心室心肌CTGF蛋白及mRNA表达明显升高(P<0.01);与模型组比较,辛伐他汀组、福辛普利组和联合用药组±dp/dt_(max)明显升高,LVMI、LVEDP明显下降,左心室心肌CTGF蛋白及mRNA表达明显下降,其中联合用药组表达水平最低(P<0.01)。结论辛伐他汀与福辛普利单用及联合应用均可有效改善心功能、消退心肌肥厚,联合用药对心肌纤维化抑制作用优于单独用药。     

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.