TNF-α,IL-6及ICAM-1在急性肝损伤时肠源性内毒素血症中的作用

目的探讨肿瘤坏死因子（TNF）-α,白细胞介素（IL）-6及细胞间黏附分子（ICAM）-1在急性肝损伤肠源性内毒素血症中的作用机制。方法取Wistar大鼠20只随机分为2组,正常对照组（A组）及急性肝损伤造模组（B组）,每组各10只。测定大鼠血浆内毒素、谷丙转氨酶（ALT）及血浆TNF-α,IL-6水平,RT-PCR方法检测肝脏组织ICAM-1 mRNA的表达,取肝脏行病理学检测。结果与A组相比,B组血浆内毒素,ALT,TNF-α,IL-6水平明显升高（P〈0.01）,ICAM-1 mRNA的表达明显增加（P〈0.01）。肝脏病理检测结果显示,B组大鼠肝细胞呈弥漫性大片状坏死,肝窦结构被破坏,汇管区可见大量炎症细胞浸润。结论TNF-α,IL-6及ICAM-1在急性肝损伤肠源性内毒素血症中起着重要作用。     

赤芍承气汤对内毒素二次打击后急性肝损伤大鼠细胞因子的影响

目的:研究赤芍承气汤对内毒素二次打击后急性肝损伤大鼠细胞因子的影响,阐述其对肝衰竭的防治机制。方法:将75只SD大鼠随机分为正常组(A),模型组(B),赤芍承气汤低(C)、中(D)、高(E)剂量组,培菲康组(F),造模前3天开始灌胃,末次灌胃1h后,除正常组外其余组大鼠通过D-氨基半乳糖腹腔注射24 h后成肝衰竭模型对SD大鼠制造第一次打击,之后给予赤芍承气汤或培菲康治疗,再腹腔注入脂多糖(LPS,内毒素的主要成分)作为第二次打击。观察大鼠行为学变化,二次打击后2h、8h处死大鼠,测定各组大鼠血清天门冬氨酸转氨酶(AST)、丙氨酸转氨酶(ALT)、总胆红素(TBil)、内毒素(ET)水平、血浆肿瘤坏死因子-α(TNF-α)、白介素(IL)-6、IL-1β,观察肝组织病理学。结果:二次打击致各组大鼠ALT、AST、TBil、ET、TNF-α、IL-6、IL-1β水平明显高于正常组,肝脏内炎细胞浸润、坏死明显,药物干预组大鼠相关指标较模型组明显降低(P0.05),肝组织病变减轻。结论:赤芍承气汤对内毒素二次打击急性肝损伤大鼠具有防治作用,该方能减轻其肝脏的损伤,改善肝脏功能,提高其大鼠生存率,其疗效机制可能与减轻内毒素血症从而切断了部分内毒素的信号传导通路,有效抑制炎症信号通路的激活,减轻TNF-α等炎症介质的释放进而减轻肝损伤有关。     

急性肝损伤大鼠肠源性内毒素血症形成机理及其作用的实验研究

探讨急性肝损伤大鼠肠源性内毒素血症的形成机理及肠源性内毒素血症在急性肝损伤过程中的作用.采用皮下注射硫代乙酰胺（TAA）600 mg/kg制作大鼠急性肝损伤动物模型,取回肠内容物、肝、脾、淋巴结作细菌培养,检测血浆及回肠内容物内毒素含量.行血浆D-乳酸的检测.取肝脏和回肠作病理切片.结果显示TAA诱导大鼠急性肝损伤后,血浆及回肠内容物内毒素水平上升明显（P＜0.01）,血浆TNF-α含量升高明显（P＜0.01）,且与内毒素水平升高呈正相关（P＜0.01）.同时出现肠道菌群失调,肠道通透性增加,肠道细菌移位.回肠病理所示肠绒毛明显变短、破坏、炎性细胞浸润增多.因此肠道菌群失调、肠粘膜结构改变、肠道通透性增加及肠道细菌移位是形成肠源性内毒素血症的重要因素.内毒素可直接或通过诱导TNF-α加重肝损伤.     

枳黄方对急性酒精性肝病大鼠TNF-α和内毒素的影响

目的：通过观察枳黄方对大鼠急性酒精性肝损伤肝组织TNF—α的变化及其血浆内毒素水平的改变，验证此方对大鼠急性酒精性肝病的防治作用。方法：将75只Wistar大鼠随机分为枳黄方组、模型组及正常组，采用免疫组化法测量肝组织内TNF—α值，用生化法检测血浆内毒素水平。结果：枳黄方组大鼠血浆内毒素水平高于正常组（P〈0．05），但显著低于模型组（P〈0．01），肝组织TNF-α和血清ALT水平高于正常组（P〈0．01），但显著低于模型组（P〈0.01）。并且血浆内毒素水平与肝组织TNF—α活性变化呈正相关（r=0．993，P〈0．01）。结论：枳黄方合剂可显著降低急性酒精性肝病大鼠血液中内毒素水平及肝脏中TNF-α水平，对大鼠急性酒精性肝病有较好治疗作用。     

亚低温对急性肺损伤大鼠NF-κB、TNF-α影响的研究

目的探讨亚低温对内毒素（LPS）致急性肺损伤大鼠的保护作用及可能机制。方法雄性SD大鼠48只,按随机数字表法分为常温内毒素组（A组,n=12）、亚低温内毒素组（B组,n=12）、常温空白对照组（C组,n=12）、亚低温空白对照组（D组,n=12）。腹腔注射内毒素制备急性肺损伤大鼠模型,观察不同时间段各组大鼠血气变化、血清NF-κB、TNF-α含量变化以及处死后各组大鼠肺组织病理形态学变化和干湿重变化。结果与两组空白对照组相比,内毒素两组大鼠PCO2、肺含水量、肺血清NF-κB、TNF-α含量均明显升高（P〈0．05）,病理形态学显示肺组织中性粒细胞浸润、毛细血管充血、水肿及出血明显。与常温内毒素组相比,亚低温内毒素组大鼠肺组织病变明显减轻,各生物学指标及NF-κB、TNF-α水平也相应下降（P〈0．05）。结论亚低温能明显减少急性肺损伤大鼠血清中NF-κB、TNF-α含量,延缓了急性肺损伤的发展进程。     

黄芩苷对急性肝衰竭大鼠肝脏核转录因子-κB表达的影响

目的观察急性肝衰竭大鼠肝脏NF-κB的表达水平及黄芩苷对其表达的影响。方法雄性SD大鼠106只随机分为正常组、肝衰竭组和黄芩苷组。肝衰竭组和黄芩苷组采用腹腔注射D-氨基半乳糖制备大鼠急性肝衰竭模型;黄芩苷组于造模后每隔12 h以120 mg/kg剂量腹腔注射。造模后24 h、72 h、120 h和168 h处死大鼠。全自动生化仪检测血清ALT、AST和TBil水平;HE染色观察肝脏病理学变化;RT-PCR法检测肝组织NF-κB、TNFα、Caspase-3 mRNA表达;免疫组化法检测肝组织NF-κB蛋白表达。结果黄芩苷组大鼠168 h存活率明显高于肝衰竭组。黄芩苷组大鼠各时间点血清ALT、AST、TBil水平较肝衰竭组明显降低（F=173.584,158.329,74.902;P〈0.01）。黄芩苷组NF-κB、TNFα、Caspase-3 mRNA表达趋势与肝衰竭组相同,72 h达高峰,但表达量较肝衰竭组明显减少,差异有统计学意义（F=603.801,42.174,27.222,P〈0.001,P〈0.001,P=0.001）。黄芩苷组NF-κB蛋白的表达也于72 h达到最大值,但其表达量较肝衰竭组减少,其差异有统计学意义（F=8.903,P=0.017）。结论黄芩苷对D-氨基半乳糖诱发的大鼠急性肝衰竭有保护作用,其机制可能与黄芩苷下调NF-κB、TNFα和Caspase-3的表达有关。     

连翘对重症急性胰腺炎大鼠肝组织中NF-κB和Foxp3表达的影响

目的探讨核因子NF-κB和Foxp3在重症急性胰腺炎（SAP）肝损伤中的作用及连翘对其表达活性的影响。方法雄性Wistar大鼠80只,随机分成假手术组（SO组）、SAP组和干预组,其中干预组分连翘高、中、低剂量组和阳性对照组（PDTC）。牛磺胆酸钠溶液在胰胆管远端注射造模,SO和SAP组于术后3、6、12 h,干预组于术后12 h处死大鼠,分别留取标本。测各组血淀粉酶（AMY）、ALT及TNFα水平,鲎试剂法测血浆内毒素水平,流式细胞术测外周血Treg百分数,对胰腺及肝脏进行病理学检查及评分,RT-PCR法检测肝脏组织中NF-κBmRNA和Foxp3mRNA表达量。组间比较采用单因素方差分析,进一步进行多重比较,采用LSD法进行统计学处理,各指标间相关性分析采用直线相关分析。结果与SO组比较,SAP组中各项指标均随时间升高,于12 h达高峰。与SAP12 h组相比,干预组（大鼠死亡率为0）肝脏组织中的NF-κBmRNA和Foxp3mRNA表达明显降低（P〈0.01）,与Treg呈正相关（r=0.738,P〈0.01）。随连翘剂量增加,AMY、ALT及TNFα水平均明显降低,肝脏和胰腺组织炎症明显减轻,高剂量组和阳性对照组相比较无明显差异（P〉0.05）。结论 NF-κB的激活参与SAP肝损伤的发生,连翘能显著降低NF-κB的活性及肝脏组织中NF-κBmRNA和Foxp3mRNA的表达,减轻SAP肝损伤的严重程度。     

肝脏X受体激活对α-GalCer诱导的小鼠肝损伤保护机制探讨

肝脏X受体（LXR）属于核受体超家族成员,对脂类代谢相关基因的转录调控起关键作用,同时具有调节免疫反应和抗炎效应。目的：研究LXR激活对仅．GalCer诱导的小鼠肝损伤保护作用的可能机制。方法：15只C57BL／6J小鼠随机分为正常对照组、α-GalCer模型组和LXR治疗组,后两组以仅α-GalCer腹腔注射诱导肝损伤模型．LXR治疗组于造模前连续7d腹腔注射LXR激动剂T0901317。造模6h后处死小鼠,行肝组织病理学检查和血清AIJT、AST水平检测,免疫组化染色检测肝组织白细胞介素-6（IL-6）表达．蛋白质印迹法检测肝内P13K／Akt／NF—κB信号通路激活情况,实时RT-PCR检测肝组织肿瘤坏死因子-α（TNF-α）、诱导型一氧化氮合酶（iNOS）mRNA表达。结果：与正常对照组相比,α-GalCer模型组小鼠肝损伤明显。血清转氨酶水平升高,肝组织IL-6、TNF-α仅、iNOS表达上调．P13K／Akt／NF—κB信号通路激活。LXR治疗组肝损伤和血清转氨酶水平较α-GalCer模型组显著改善,肝组织炎症介质表达下调,P13K／Akt／NF—κB信号通路激活受抑。结论：LXR激活可调节免疫反应,抑制肝脏炎症,从而显著减轻α-GalCer诱导的小鼠肝损伤．其机制可能与抑制P13K／Akt／NF—κB信号通路激活有关。     

核因子-κB及其下游因子TNF-α、Bcl-2在急性肝损伤中的作用及机制

目的:探讨核因子-κB(nuelear factor-kappa B,NF-κB)及其下游因子TNF-α、Bcl-2在急性肝损伤的作用及机制.方法:(↑○) Wistar大鼠90只随机分为正常组,硫代乙酰胺(TAA)造模组及脯氨酸二硫代氨基甲酸酯(PDTC)预处理组(n=30).三组大鼠分别于造模完成后6、24、48 h 3个时间点处死.每个时间点各取10只大鼠.鲎试剂显色基质法测定大鼠血浆内毒素,放免法测定血浆TNF-α水平,取肝脏行病理学及免疫组化检测.制备肝脏单细胞悬液检测肝细胞凋亡指数.结果:与正常组相比,TAA细在6、24、48h时间点均可见血浆内毒素(Eu/mL)及TNF-α(ug/L)水平明显升高(内毒素:0.64±0.08 vs 0.23±0.02,P<0.01;0.96±0.14 vs 0.25±0.02,P<0.01;1.15±0.17 vs 0.25±0.03,P<0.01;TNF-α:5.97±1.07 vs 1.44±0.52,P<0.01;12.52±2.09 vs 1.57±0.62,P<0.01;10.76±1.95 vs 1.49±0.57.P<0.01),肝组织NF-κB及Bcl-2明显活化(NFκB:87.1l%±8.23% vs 4.64%±1.82%.78.55%±6.82% vs 4.58%±1.91%,74.27%±6.26%vs 4.73%±1.89%,均P<0.01;Bcl.2:51.11%±4.23% vs 6.74%±3.93%.71.59%±6.82% vs 6.68%±3.88%,82.19%±8.54% vs 6.81%±4.14%,均P<0.01).随着时间延长,肝细胞凋亡指数增加,TAA组肝脏病理变化明显,抑制NF-κB活性后,可见肝脏病理变化减轻.结论:TAA所致急性肝损伤中,TNF-α水平明显升高,发挥了促炎及诱导凋亡作用.其促凋亡作用相对拮抗Bcl-2抗凋亡作用.NF-κB通过调控其下游基因加重肝脏损伤.     

枳黄方对急性酒精性肝损伤大鼠内毒素信号转导通路中白细胞分化抗原14的影响

[目的]探讨酒精性肝损伤时，枳黄方对内毒素信号通路中白细胞分化抗原14（CD14）表达的影响。[方法]将75只Wistar大鼠随机分为空白对照（正常）组、酒精攻击（模型）组、枳黄方（治疗）组，10d后，处死大鼠，取大鼠血清和肝脏测定丙氨酸氨基转移酶（ALT）、天冬氨酸转氨酶（AST），苏木精-伊红染色观察肝脏病理变化，基质染色法测定血清内毒素，免疫组化法测定肝脏肿瘤坏死因子α（TNF-α），RT—PCR法测定肝组织CD14mRNA的变化。[结果]治疗组肝脏病理表现较模型组好，其血清内毒素、ALT、AST和肝组织TNF-α、CD14mRNA表达水平均高于正常组（P〈0．05，〈0．01，〈0．01，〈0．01，〈0．05），且均显著低于模型组（均P〈0．01）。[结论]枳黄方能显著降低内毒素信号转导通路上CD14基因水平的表达，减少肝组织TNF-α的表达，这可能是其对大鼠酒精性肝损伤有较明显保护作用的机制之一。     

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.