国内无痛胃肠镜开展近况调查

目的 调查国内医院无痛胃肠镜的开展近况.方法 以国内不同省份的各级医院消化内镜中心(室)为调查对象,采用电子邮件或电话问卷调查方式对无痛胃肠镜开展情况进行汇总分析.结果 共有169家医院纳入调查分析,分布于28个省(自治区或直辖市),占国内大陆省份的90.3％ (28/31),其中三级医院为46家,二级医院为91家,一级医院为32家.110家(65.1％,110/169)开展了无痛胃肠镜,其中93.5％ (43/46)的被调查三级医院、68.1％(62/91)的二级医院及15.6％ (5/32)的一级医院开展了无痛胃肠镜,三级医院开展率明显高于二级医院(P＜0.05),二级医院则显著高于一级医院(P＜0.05).在110家开展无痛胃肠镜的医院中,只有10家(9.1％)消化内镜室配备了专职麻醉医师,且这10家均为三级医院,占开展无痛胃肠镜三级医院的23.3％( 10/43).110家开展无痛胃肠镜的医院中,98家(89.1％)使用或联合使用丙泊酚作为镇静剂.结论 国内无痛胃肠镜在过去十余年内得到迅速发展,但一、二级医院开展率仍较低,且专职麻醉医师(或麻醉护士)普遍缺少是目前面临的主要问题.     

肝硬化食管静脉曲张破裂出血序贯治疗的临床应用价值

目的 评价曲张静脉套扎术(EVL)+不同硬化剂曲张静脉硬化术(EVS)序贯治疗肝硬化食管静脉曲张破裂出血的疗效及安全性.方法 回顾性总结314例肝硬化食管静脉曲张破裂出血内镜治疗患者的临床资料,包括单纯EVL治疗者112例(EVL组)、单纯鱼肝油酸钠硬化治疗者48例(EVS1组)、单纯聚桂醇硬化治疗者40例(EVS2组)、套扎+鱼肝油酸钠硬化序贯治疗者26例(EVLS1组)、套扎+聚桂醇硬化序贯治疗者88例(EVLS2组),统计各组曲张静脉治疗有效率、静脉曲张复发率、并发症发生率并进行对比分析.结果 EVL组、EVS1组、EVS2组、EVIS1组、EVLS2组曲张静脉治疗有效率比较差异均无统计学意义[85.7％ (96/112)、83.3％ (40/48)、92.5％ (37/40)、92.3％(24/26)、94.3％ (83/88),P＞0.05],但EVLS1组和EVLS2组曲张静脉完全消失率均明显高于其他3组[88.5％(23/26)和87.5％(77/88)比58.0％(65/112)、62.5％(30/48)、70.0％(28/40),P＜0.05],而EVLS1组与EVLS2组比较差异无统计学意义(P＞0.05).EVS1组再出血率最高(18.8％,9/48) (P ＜0.05),其次是EVL组(11.6％,13/112),均高于EVS2组、EVLS1组和EVLS2组[7.5％(3/40)、7.7％ (2/26)、6.8％ (6/88),P＜0.05],后3组再出血率相似(P＞0.05).治疗后随访6 ～18个月,EVL组静脉曲张复发26例(23.2％,26/112),EVS1组复发8例(16.7％,8/48),EVS2组复发6例(15.0％,6/40),EVLS1组复发4例(15.4％,4/26),EVLS2组复发9例(10.2％,9/88);EVL组复发率最高(P＜0.05),EVLS2组复发率最低(P＜0.05),EVS1组、EVS2组和EVLS1组复发率相似(P＞0.05).EVS1组总体并发症发生率(32.2％,49/152)明显高于其他4组(P＜0.05),而EVL组(14.5％,32/220)、EVLS2组(19.6％,22/112)、EVLS1组(22.7％,25/110)、EVLS2组(15.8％,34/229)4组间比较差异无统计学意义(P＞0.05).结论 EVL+鱼肝油酸钠EVS或+聚桂醇EVS序贯治疗肝硬化食管静脉曲张破裂出血是安全而有效的,尤以EVL+聚桂醇EVS序贯治疗效果显著,有可能成为治疗食管静脉曲张出血并防止再出血的最佳选择.     

河南省市县级医院消化内镜医师内镜诊疗水平现况调研

目的了解河南省市县级医院消化内镜医师的内镜诊疗水平及现状。 方法采用自行设计的调查问卷,对2016年1月至2017年1月参加河南省人民医院消化内科内镜培训的市县级医院的内镜医师进行调查问卷,统计内镜诊疗开展情况、工作量及内镜医师参加培训情况。 结果共有114人参与调查,其中有效调查问卷104份。参与调查的医师来自三级医院者占54.8%、二级医院者占45.2%,有10年以上内镜工作经验者占47.1%。均已开展胃肠镜检查技术的市县级医院,分别有26.9%、23.1%、58.7%和87.5%的内镜医师未开展内镜下止血治疗、高频电切除胃肠道息肉、EMR法切除胃肠道息肉和ESD术。并且,参加内镜培训的医师中,仅有19.4%能被提供急诊胃镜下止血的操作机会。 结论我省市县级医院消化内镜诊疗技术水平参差不齐且整体水平较低下,建立并完善适合市县级医院消化内镜医师操作水平的有效的培训模式迫在眉睫。     

关于消化内镜基础操作与诊断的培训

消化内镜是目前诊治消化道疾病最常用、最直观的检查手段,被视为许多消化道疾病诊断的金标准.我国消化内镜诊治技术近年来发展迅速,很多消化内镜诊治项目已普及到基层医疗单位.根据我们2010年开展的全国消化内镜诊治项目调查,县级以上医院100％开展了胃镜检查、88.2％的县级医院开展了结肠镜检查,并且内镜的治疗技术如息肉切除在省级医院开展率为100％、地市级医院为78.0％、县级医院也已达到41.2％[1].但是,目前国内在消化内镜诊治操作方面仍存在重内镜操作、轻理论学习,重内镜检查数量、轻内镜诊治质量,以及缺乏规范化内镜基础操作和诊断技术培训等问题.这些问题的存在将直接影响对消化道疾病的正确诊断和治疗,必将影响、甚至阻碍该技术在我国的长期发展和提高.     

套扎与硬化对肝硬化食管静脉曲张疗效的Meta分析

目的 比较内镜下套扎(EVL)与硬化(EVS)对肝硬化食管静脉曲张的疗效.方法 检索维普数据库、万方数据库和中国生物医学文献数据库、Pubmed 1985年1月-2012年7月发表的有关内镜下EVL和EVS治疗肝硬化食管静脉曲张的相关文献,采用RevMan 4.2进行Meta分析.结果 有9项前瞻性随机对照试验纳入研究.Meta分析结果显示,EVL治疗的再出血率低于EVS治疗(OR=0.52,95％ CI:0.32 ～0.85,P=0.009),并发症少于EVS治疗(OR=0.30,95％ CI:0.20 ～ 0.43,P＜0.00001),达到食管静脉曲张消失需要内镜治疗次数少于EVS治疗(WMD=-1.24,95％ CI:-2.09 ～-0.38,P=0.004),而食管静脉曲张复发率高于EVS治疗(OR =2.21,95％ CI:1.47 ～3.32,P=0.0001),在急诊止血率、静脉曲张消失率、死亡率方面,两组差异无统计学意义.结论 与EVS治疗相比,EVL治疗再出血率低、并发症少、食管静脉曲张消失所需治疗次数少,因此EVL疗效更好,可作为内镜下治疗食管静脉曲张的首选.     

内镜下套扎联合硬化剂治疗食管静脉曲张破裂出血的临床疗效及安全性

目的 探讨内镜下食管静脉曲张套扎术(EVL)联合内镜下食管静脉曲张硬化术(EVS)治疗食管静脉曲张破裂出血(EVB)的临床疗效和安全性.方法 选择60例EVB患者,随机分为观察组、对照组各30例,观察组采用EVL+EVS治疗,对照组采用单纯EVL.分别观察两组活动性出血止血情况、首次治疗后静脉曲张情况、达到消除所需时间及治疗次数、再出血、静脉曲张复发、并发症等情况.结果 两组活动性出血止血成功率均为100％.观察组静脉曲张消除率为96.7％,与对照组(90.0％)比较差异无统计学意义(P＞0.05),但其首次治疗后的静脉曲张消除率(70.0％)明显高于对照组(46.7％)(P＜0.05),达到静脉曲张消除所需时间和治疗次数均显著低于对照组(P均＜0.05).观察组早发再出血率、迟发再出血率、静脉曲张复发率分别为6.6％、6.7％、3.3％,均显著低于对照组(20.0％、23.3％、23.3％)(P均＜0.05).观察组并发症发生率为13.3％,显著低于对照组(43.3％)(P＜0.05).结论 EVL+EVS是EVB急诊止血和预防再出血的有效方法.     

食管静脉曲张硬化与结扎加硬化治疗食管静脉曲张的对照研究

目的研究食管静脉曲张硬化与结扎防治出血的效果.方法60例乙型病毒性肝炎肝硬化、食管静脉曲张出血的病人分为两组,食管静脉硬化治疗(EVS)组30例,食管静脉结扎加硬化治疗(EVL+EVS)组30例,结果在EVS组和EVL+EVS组中,静脉曲张消失和基本消失者分别为28例(90%)和30例(100%),两组比较无显著差异.达到静脉曲张消失所需硬化治疗次数及硬化剂所用量,EVL+EVS组均明显少于EVS组,两组并发症发生率无显著差异.EVS组随访26.9±4.5个月,EVL+EVS组22.7±5.3个月,随访期食管静脉曲张复发率EVS、EVL+EVS组分别为9例(30%)和13例(43.3%),EVL+EVS组高于EVS组,反复出血分别为4例和3例.住院天数EVS组和EVL+EVS组分别为27.1±5.0和28.8±9.2天,两组无显著差异.所消耗结扎器、硬化剂和手术费用EVS组和EVL+EVS组分别为5378.50±899.00元和7703.33±2120.70元,两组比较P＜0.001,EVL+EVS组明显高于EVS组,结论本研究提示EVL+EVS较单一EVS无明显优越性.     

陕西省消化内镜现况调查分析

随着科技及医疗技术水平的发展,消化内镜这项侵入性微创性诊疗技术在我国发展较为全面和成熟,已成为消化内科疾病诊治最重要的手段之一.但是,我们还不是很了解陕西省各级医院消化内镜的具体情况.为了推动陕西省消化内镜更好的发展,了解不同级别、不同规模陕西省内医院消化内镜工作量、开展项目、内镜人员的配备及内镜消毒等现状,我们在中华医学会陕西消化内镜学会的领导下,调查了2009年1月至2010年1月年陕西省不同地区不同等级医院的消化内镜的诊治现况,报道如下.一、对象与方法1.对象:陕西省医院120家.调查内容包括:拥有消化内镜的数量及种类;内镜专业医疗人员配比情况;内镜下开展的诊疗项目,如进行常规胃肠镜检查的工作量,内镜下开展介入治疗项目等情况;内镜检查工作量;胃镜消毒方法、消毒剂的种类、消毒时间等消毒情况.     

EVS、EVS+EVL续贯EVS和EVL续贯EVS治疗食管静脉曲张的疗效比较

目的:比较内镜下食管静脉曲张硬化治疗(EVS)、EVS EVS加套扎(EVL)续贯EVS和EVL续贯EVS治疗食管静脉曲张的疗效.方法:乙型病毒性肝炎肝硬化食管静脉曲张破裂出血患者130例,随机分为EVS治疗组50例,EVS EVL续贯EVS组40例,EVL续贯EVS组40例,比较3组食管静脉曲张的消失率、并发症、硬化剂总用量,患者住院天数和远期复发出血率.结果:三组患者治疗后食管静脉曲张消失率无差异;EVS组硬化剂应用总量、治疗次数和住院天数都高于EVS EVL续贯EVS组,EVL续贯EVS组(95.64±37.51 mL vs 55.90±38.93 mL,32.15±26.97 mL;3.64±1.32 vs 1.85±1.18,1.35±0.88;25.92±8.69 vs 20.6±5.00 d,17.55±4.62 d;P均<0.05),而后两组之间没有差异;EVL续贯EVS组食管静脉曲张复发率高于另外两组(45% vs 12%,20%,P<0.05),而后两组间没有差异.3组间再出血发生率及并发症的发生率没有差别.结论:EVL续贯EVS和EVS EVL续贯EVS在食管静脉曲张的治疗上优于单纯EVS,尤其后者兼具EVL和EVS的优点.     

新型过氧乙酸溶液消毒消化内镜的效果评价

目的 探讨新型过氧乙酸溶液应用于消化内镜消毒的临床价值.方法 选择消化内镜40条分成两组,每组胃镜和肠镜各10条,观察组接受新型过氧乙酸溶液消毒10 min,对照组接受常规2％戊二醛溶液消毒10 min,比较两组消毒合格率,评价新型过氧乙酸溶液消毒的有效性.有效性获得证实后,再选择消化内镜80条分成四组,每组胃镜和肠镜各10条,分别接受新型过氧乙酸溶液消毒2 min、3 min、4 min和5 min,比较消毒合格率,探讨新型过氧乙酸溶液消毒的高效性.结果 对照组胃镜消毒合格率为100％ (10/10),肠镜消毒合格率为90％(9/10),消毒后胃镜和肠镜均能检出菌落;观察组胃镜和肠镜消毒合格率均为100％,且消毒后胃镜和肠镜均不再检出菌落,明显优于对照组.新型过氧乙酸溶液消毒3 min组、4 min组和5 min组胃镜消毒合格率均为100％(10/10),明显高于2 min组的30％ (3/10) (P ＜0.05),但3 min组仍可检出菌落;2 min组肠镜消毒均不合格,4 min组和5 min组肠镜消毒合格率均为100％,明显高于3 min的80％ (8/10) (P ＜0.05),但4 min组仍可检出菌落.结论 新型过氧乙酸溶液可用于临床消化内镜的消毒,较2％戊二醛溶液更符合消化内镜高水平消毒的要求.     

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.