罗格列酮对小鼠日本血吸虫病肝纤维化基质金属蛋白酶-2的影响

目的:研究PPARγ配体罗格列酮治疗小鼠血吸虫病肝纤维化,血清MMP-2与TIMP-2的变化及肝组织MMP-2与TIMP-2的基因表达方法:昆明小鼠50只,随机分为正常对照组A、感染对照组B、吡喹酮治疗组C、罗格列酮治疗组D及罗格列酮加吡喹酮治疗组E.除正常对照组外,其余各组均建立血吸虫病肝纤维化小鼠模型.用ELISA法检测血清MMP-2及TIMP-2的含量,实时荧光定量PCR反应观察小鼠肝组织MMP-2 mRNA及TIMP-2 mRNA的表达.结果:D,E组血清MMP-2的含量(306.0±62.3μg/L,312.0±54.3μg/L)及肝组织MMP-2 mRNA的表达[-19.1±(-6.0),-20.4±(-6.2)]高于A组[221.3±39.2μg/L,-26.3±(-5.3):P<0.051,但明显低于B组[411.3±57.5μg/L,-12.2±(-4.4),P<0.05]和C组[402.9±57.2μg/ L,-12.8±(-4.0),P<0.051.B,C,D和E组血清TIMP-2的含量及肝组织TIMP-2 mRNA的表达均显著高于正常对照组[209.3±60.5μg/L,-20.5±(-4.7);213.5±66.0μg/L,-19.9±(-5.1);223.6±65.3μg/L,-18.8±(-5.5);224.5±64.4μg/L,-19.7±(-4.3) vs 150.4±46.5μg/L,-27.2±(-6.0),P<0.05],但这4组间TIMP-2值无显著性差异(P>0.05).结论:MMP-2在血吸虫病肝纤维化形成中起促进作用,PPARγ配体罗格列酮的抗肝纤维化机制与其下调MMP-2的表达有一定关系.     

肝炎平对肝纤维化大鼠血浆同型半胱氨酸水平的影响

目的探讨肝炎平对肝纤维化大鼠血浆同型半胱氨酸、半胱氨酸、半胱．甘氨酸及谷胱甘肽水平的影响。方法制备CCl4大鼠肝纤维化模型。动物随机分为正常对照组（N组）、肝炎平治疗组（G组）、和络舒肝胶囊治疗组（H）及肝纤维化模型组（D组）。采用高效液相色谱法（HPLC）测定各组血浆同型半胱氨酸（homocysteine）、半胱氨酸（cysteine）、半胱．甘氨酸（cysteinyl-glycine）及谷胱甘肽（glutathione，GSH）水平。结果肝炎平治疗组及和络舒肝胶囊治疗组同型半胱氨酸含量明显下降，与模型组相比较有显著性差异（P〈0．05）。结论肝炎平通过调节肝纤维化大鼠体内含硫氨基酸代谢，降低血浆同型半胱氨酸，可能是其抗大鼠肝纤维化作用的机制之一。     

吡喹酮治疗对血吸虫病肝纤维化小鼠血清细胞因子水平的影响

目的　研究吡喹酮治疗血吸虫肝纤维化小鼠前后血清 TNF-α,IFN -γ水平的变化。方法　制备血吸虫肝纤维化小鼠模型 ,应用 EL ISA方法检测血吸虫肝纤维化小鼠在吡喹酮治疗前后血清TNF-α,IFN-γ水平的变化。结果　吡喹酮治疗组 TNF-α含量较感染组显著降低 (P<0 .0 1) ,吡喹酮治疗组 IFN-γ含量较感染组显著增加 (P<0 .0 1)。结论　吡喹酮可通过降低血吸虫肝纤维化小鼠血清 TNF-α的含量 ,提高 IFN-γ的含量从而发挥抗肝纤维化的作用。     

中药加味四逆散对血吸虫病小鼠肝功能的影响

目的观察加味四逆散对血吸虫病肝纤维化小鼠肝功能的影响。方法NI H小鼠经皮肤人工感染血吸虫尾蚴后随机分为4组:B组(模型组)、C组(吡喹酮组)、D组(吡喹酮+加味四逆散组)和E组(吡喹酮+秋水仙碱组),同时设A组(正常对照组)。病理观察小鼠肝组织肝纤维化形成后第21 d开始给药治疗,C组、D组、E组在第45 d时予以吡喹酮一次性灌胃杀虫,第78 d心脏采血,生物化学法测血清ALT、TBiL及血浆ALB含量,取肝、脾组织称重,计算脏器系数。结果吡喹酮+加味四逆散组小鼠治疗后肝脏系数低于模型组、吡喹酮组、吡喹酮+秋水仙碱组(P<0.05),高于正常对照组(P<0.05);脾脏系数低于模型治疗组和吡喹酮组(P<0.05),与吡喹酮+秋水仙碱组比较差异无统计学意义(P>0.05);血清ALT、AST水平与模型组、吡喹酮组、吡喹酮+秋水仙碱组比较差异有统计学意义(P<0.05),TBiL水平与模型组、吡喹酮组比较差异有统计学意义(P<0.05),与吡喹酮+秋水仙碱组比较差异无统计学意义(P>0.05);ALB水平高于模型组(P<0.05),低于正常对照组(P<0.05)。结论中药加味四逆散联合吡喹酮治疗能有效改善血吸虫...     

血浆同型半胱氨酸水平与急性脑梗死患者近期预后的关系研究

目的探讨血浆同型半胱氨酸水平与急性脑梗死患者近期预后的关系。方法选取我院2012年2月—2014年2月收治的急性脑梗死患者92例为观察组,同时期在我院体检健康者92例为对照组。观察组患者入院后给予常规治疗及对症治疗,采用荧光标记免疫法检测两组受检者血浆同型半胱氨酸水平,并根据血浆同型半胱氨酸水平将观察组患者分为A组42例(血浆同型半胱氨酸水平15μmol/L)和B组50例(血浆同型半胱氨酸水平正常)。分别于入院时、入院4周后采用美国国立卫生研究院卒中量表(NIHSS)对观察组患者进行神经功能缺损评分。结果观察组患者血浆同型半胱氨酸水平为(17.73±5.62)μmol/L,高于对照组的(10.66±3.82)μmol/L(P0.05)。入院时A、B组患者神经功能缺损评分比较,差异无统计学意义(P0.05);入院4周后A组患者神经功能缺损评分高于B组(P0.05)。结论急性脑梗死患者血浆同型半胱氨酸水平较正常人升高,与急性脑梗死的发病有关;血浆同型半胱氨酸水平升高的急性脑梗死患者神经功能缺损程度较重,近期预后较差。     

罗格列酮对日本血吸虫病肝纤维化小鼠肝组织核因子-κB和过氧化物酶体增殖物激活受体γ表达的影响

目的:观察日本血吸虫病肝纤维化小鼠肝脏肝组织核因子-κB(NF-κB)的活性和过氧化物酶体增殖物激活受体γ(PPARγ)的表达,及PPARγ配体罗格列酮对其表达的影响.方法:50只昆明小鼠,随机分为正常对照组、感染对照组、吡喹酮治疗组、罗格列酮治疗组及罗格列酮加吡喹酮治疗组.除正常对照组外,其余各组均建立血吸虫病肝纤维化小鼠模型.用HE染色观察肝组织光镜下的病理改变.用Western blot方法,实时荧光定量PCR反应观察小鼠肝组织NF-κB的活性变化与PPARγmRNA的表达.结果:罗格列酮加吡喹酮治疗组小鼠肝脏的炎性反应和纤维化病理改变较其他模型组轻(P＜0.05).感染对照组NF-κB活性(141.11±15.37)最强,明显高于其余各组(正常对照组:78.89±18.12;吡喹酮组:112.89±20.17:罗格列酮组:108.89±20.47;罗格列酮加吡喹酮组:88.89±19.34)(P＜0.05).感染对照组[-27.315±(-6.348)].及吡喹酮治疗组[-25.647±(-5.694)]PPARγ mRNA表达较正常对照组[-16.557±(.3.022)]及罗格列酮治疗组[-18.217±(-4.498)]、罗格列酮加吡喹酮治疗组[-18.212±(-3.909)]显著减弱(P＜0.05).结论:PPARγ及NF-κB在血吸虫病肝纤维化形成中起一定作用.PPARγ配体罗格列酮有明显的抗日本血吸虫病肝纤维化效应,其抗纤维化机制与PPARγ配体激活PPARγ表达的同时抑制NF-κB的活性有关.     

罗格列酮对日本血吸虫病肝纤维化小鼠肝组织核因子-κB和过氧化物酶体增殖物激活受体γ表达的影响

目的观察日本血吸虫病肝纤维化小鼠肝脏肝组织核因子-κB(NF-κB)的活性和过氧化物酶体增殖物激活受体γ(PPARγ)的表达,及PPARγ配体罗格列酮对其表达的影响.方法50只昆明小鼠,随机分为正常对照组、感染对照组、吡喹酮治疗组、罗格列酮治疗组及罗格列酮加吡喹酮治疗组.除正常对照组外,其余各组均建立血吸虫病肝纤维化小鼠模型.用HE染色观察肝组织光镜下的病理改变.用Western blot方法,实时荧光定量PCR反应观察小鼠肝组织NF-κB的活性变化与PPARγmRNA的表达.结果罗格列酮加吡喹酮治疗组小鼠肝脏的炎性反应和纤维化病理改变较其他模型组轻(P＜0.05).感染对照组NF-κB活性(141.11±15.37)最强,明显高于其余各组(正常对照组78.89±18.12;吡喹酮组112.89±20.17罗格列酮组108.89±20.47;罗格列酮加吡喹酮组88.89±19.34)(P＜0.05).感染对照组[-27.315±(-6.348)].及吡喹酮治疗组[-25.647±(-5.694)]PPARγ mRNA表达较正常对照组[-16.557±(.3.022)]及罗格列酮治疗组[-18.217±(-4.498)]、罗格列酮加吡喹酮治疗组[-18.212±(-3.909)]显著减弱(P＜0.05).结论PPARγ及NF-κB在血吸虫病肝纤维化形成中起一定作用.PPARγ配体罗格列酮有明显的抗日本血吸虫病肝纤维化效应,其抗纤维化机制与PPARγ配体激活PPARγ表达的同时抑制NF-κB的活性有关.     

血浆同型半胱氨酸与冠心病及高血压的相关性研究

目的探讨冠心病及高血压患者中,血浆同型半胱氨酸、一氧化氮水平的变化。方法对99例冠心病患者(冠心病组)与122例单纯高血压患者(高血压组)进行血浆同型半胱氨酸、一氧化氮水平的测定。结果冠心病组血浆同型半胱氨酸浓度为(18.57±7.47)μmol/L,明显高于高血压组(14.53±10.58)μmol/L(P0.01)。冠心病组血清一氧化氮浓度为(51.15±18.78)μmol/L,明显低于高血压组(70.39±41.55)μmol/L(P0.001)。结论高同型半胱氨酸血症与冠心病的发生有密切关系,并且同型半胱氨酸水平与一氧化氮呈反比,可能同型半胱氨酸水平与血管损伤的严重程度有明显的相关性。     

吡喹酮对日本血吸虫病肝纤维化的治疗作用及宿主miRNA表达变化

目的研究吡喹酮对日本血吸虫虫卵引起的肝纤维化的治疗作用及其可能的机制。方法选用BALB/c小鼠建立日本血吸虫感染小鼠模型,实验组以250 mg/(kg·d)吡喹酮连续用药3 d进行杀虫,再以600 mg/(kg·d)连续给药30 d进行抗纤维化治疗;对照组仅进行吡喹酮杀虫。以肝组织羟脯氨酸含量等指标评定小鼠肝纤维化的程度,并通过实时荧光定量PCR(real-time PCR)检测各组肝组织中某些微小RNA(microRNA,miRNA)的表达水平。各组检测结果以t检验进行统计学分析。结果经过吡喹酮治疗后,小鼠肝脏羟脯氨酸含量等肝纤维化指标明显降低,小鼠肝脏羟脯氨酸含量:感染后第75天,感染组、杀虫组、治疗组依次为(0.86±0.07)、(0.66±0.06)、(O.25±0.05)mg/g肝湿重,治疗组低于感染组和杀虫组(t=12.86,P0.01)。同时小鼠肝脏的部分miRNA表达水平发生了明显改变,治疗组与杀虫组相比较,Col I、miR-223、miR-146b、miR-142-5p、miR-199a-5p、miR-34c*、miR-195依次下调了62%、38%、75%、77%、40%、54%和56%。结论吡喹酮对日本血吸虫病肝纤维化有一定的治疗作用,其作用可能与调节某些宿主miRNA的表达水平有关。     

脑梗死发病危险性与血同型半胱氨酸水平的相关性

目的探讨血浆同型半胱氨酸水平与脑梗死发病危险性的关系。方法200例脑梗死患者测定血浆同型半胱氨酸、叶酸、维生素B12和欧洲脑卒中量表评分等指标,并与100例健康对照者相比较。结果脑梗死组的血浆同型半胱氨酸水平高于对照组(18.54±6.28μmol/L比10.35±3.64μmol/L,P<0.001);脑梗死组叶酸与维生素B12水平(分别为4.62±2.48μg/L、246.4±86.2ng/L)低于对照组(分别为8.36±1.58μg/L、348.3±58.4ng/L,P<0.001)。条件Logistic回归模型检验发现同型半胱氨酸为脑梗死的独立致病因素。脑梗死组血浆同型半胱氨酸水平与欧洲脑卒中量表评分呈负相关(r=-0.684,P<0.001),即脑梗死病情严重程度与血同型半胱氨酸水平呈正相关。脑梗死组血同型半胱氨酸水平与血叶酸和维生素B12水平呈负相关(r=-0.448,P<0.001;r=-0.264,P<0.01)。结论高同型半胱氨酸血症增加了脑梗死的发病危险性,并可加重其病情严重程度。     

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.