中老年动脉导管未闭患者介入治疗139例分析

目的 分析中老年动脉导管未闭(PDA)患者的临床特征及探讨行经导管封堵治疗的安全性.方法 选择2000年1月至2009年4月在我科介入治疗的139例40岁以上PDA患者,男22例,女117例,年龄40～74(49.8±6.8)岁,术前心功能分级为Ⅰ级64例,Ⅱ级53例,Ⅲ级16例,Ⅳ级6例,分析中老年PDA患者临床特征及观察封堵PDA前后肺动脉压和心功能的改善情况.结果 139例患者中合并肺动脉高压107例,发生率为77.0%,3例严重肺动脉高压者不适宜手术治疗,其余136例均成功行介入治疗,成功率为97.8%.封堵PDA后主动脉造影显示残余分流微量14例,少量2例,中等量分流1例,无手术相关并发症.术后心功能显著改善,肺动脉收缩压由术前(47.3±23.9)mm Hg(1 mm Hg=0.133 kPa)降至(28.1±12.3)mm Hg,肺动脉平均压由(31.7±17.4)mm Hg降至(17.9±8.8)mm Hg(均P<0.01).结论 中老年PDA患者肺动脉高压发生率高,心功能差,经导管封堵中老年PDA是一种安全有效的方法 .     

房间隔缺损合并肺动脉瓣狭窄介入治疗的临床评价

目的:探讨房间隔缺损(ASD)合并肺动脉瓣狭窄(PS)行介入治疗的临床安全性及其疗效。方法:31例患者,年龄2.5~67(中位年龄31)岁;24例经胸超声心动图(TTE)诊断为ASD合并PS,房间隔缺损最大直径为7~27(16.0±4.8)mm,7例超声心动图术前漏诊ASD,肺动脉瓣狭窄压差35~120(89.8±22.9)mm Hg(1mm Hg=0.133k Pa),所有患者术前行右心室造影检查。先行经皮球囊肺动脉瓣成形术(PBPV),而后置入房间隔缺损封堵器闭合缺损,选择的封堵器直径为12.0~38.0(22.6±5.9)mm。结果:本组28例行PBPV术及ASD介入封堵治疗28均获得成功;其中3例封堵器脱落入主动脉,介入方法取出后,再置入较大封堵器封堵成功,PBPV术后即刻右室收缩压由术前(89.8±22.9)mmHg下降至(39.8±11.3)mm Hg,肺动脉右心室跨瓣压差由术前mm Hg降至(14.8±8.9)mm Hg(P<0.001)。右心室舒张末压由术前(9.9±0.28)mm Hg降至(5.07±0.57)mm Hg(P<0.005),PBPV术后即刻跨瓣压差下降达优良为100%。术后超声心动图随访于术后即刻、1、3及6个月,疗效满意,房间隔未见残余分流。结论:同期介入治疗肺动脉瓣狭窄合并房间隔缺损安全可行,效果良好,但由于合并PS患者,超声心动图术前常常低估或漏诊ASD,因此,需先行肺动脉瓣球囊扩张术后,超声心动图重新复核ASD大小,再行ASD封堵术,必要时分期手术。     

高海拔地区老年患者房间隔缺损的介入治疗

目的探讨高原地区经导管介入封堵治疗老年患者房间隔缺损(ASD)的有效性和安全性。方法回顾性分析经导管封堵治疗的51例老年ASD患者的临床和介入治疗资料。结果全组治疗成功率90.2%,经胸超声心动图(TTE)测量ASD平均大小为(24.3±5.8)mm,封堵器平均大小为(28.2±8.6)mm,均采用国产封堵器。术后3个月平均肺动脉收缩压较术前下降明显(P<0.05),右心房、右心室内径较术前减小。微少量残余分流3例,3个月后复查分流消失。并发症发生率11.8%,无死亡。随访6⁴2个月,封堵器无移位,心功能改善。结论高原地区老年ASD患者有缺损大,肺动脉高压程度严重,并发症多的特点。严格掌握适应证,规范操作,积极治疗并发症,是成功封堵的关键。     

老年房间隔缺损患者介入治疗的临床分析

目的 探讨老年房间隔缺损患者的临床特征及行经导管封堵治疗的安全性和有效性.方法 入选2000年5月至2010年6月行经导管封堵治疗的(64.5±3.8)岁房间隔缺损患者82例.经导管封堵术中行右心导管检查.术后1d、1个月、3个月和6个月进行随访.分析老年房间隔缺损患者的临床特征,观察房间隔缺损封堵前后肺动脉压及心功能的改变情况.结果 82例房间隔缺损患者中,合并肺动脉高压37例,发生率为45.1％.封堵前的右心导管检查显示,患者肺动脉收缩压为(44.1±12.4)mm Hg(1 mm Hg=0.133 kPa),肺动脉平均压为(25.2 +6.8)mm Hg.1例重度肺动脉高压患者不适宜经导管封堵治疗,其余81例均成功行介入治疗,无手术相关并发症.36例封堵成功的肺动脉高压患者肺动脉收缩压由术前的(52.7±10.3)mm Hg下降至术后的(31.8 +6.3)mm Hg(P＜0.05),肺动脉平均压由术前的(30.9±4.7) mm Hg下降至术后的(21.8±3.4) mm Hg(P＜0.05).与术前比较,术后1d、1个月、3个月和6个月NYHA心功能分级改善.术后新发心房颤动6例.结论 老年房间隔缺损患者通常合并肺动脉高压.只要严格掌握适应证和规范操作,经导管封堵治疗老年房间隔缺损仍是一种安全有效的方法.     

国产蘑菇伞介入治疗成人动脉导管未闭的临床疗效评价

目的: 评价国产蘑菇伞经导管介入治疗成人动脉导管未闭(PDA)的临床疗效。方法: 选择我科156(男54,女102)例成人PDA实施经导管介入治疗的患者,年龄18～65(32±13)岁;体质量43.8～68.5(51±8)kg;行右心导管检查测定肺动脉压力、主动脉压力,行主动脉弓降部造影,确定PDA位置、形状及大小,PDA最窄处内径1.5～18.2 (5±5)mm。以国产蘑菇伞堵闭器行介入治疗,根据封堵实验决定能否行永久封堵。术后24 h、1、3、6 和12个月行彩色多普勒超声心动图检查随访。结果: 4例封堵后30 min肺动脉收缩压无下降,反而有轻度上升,考虑为阻力性重度肺动脉高压,撤出封堵器。余152例成功地植入封堵器,术后30 min肺动脉压收缩压由术前(48±23)mmHg降为(36±12)mmHg(P<0.05),肺动脉平均压降由术前(40±14)mmHg降为(27±11)mmHg(P<0.05),主动脉压由术前(102±13)mmHg变化至(107±14)mmHg(P>0.05)。术后30 min主动脉弓降部造影显示,119例(78.3％)封堵完全,33例(21.7％)可见极少量残余分流,术后24 h心脏彩超复查147例(96.7％)封堵完全,5例(3.3％)有少量残余分流,术后1个月彩超复查皆无残余分流;无再通和堵闭器移位等并发症发生。结论: 在不可逆性阻力性重度肺动脉高压发生前应用国产蘑菇伞经导管封堵治疗成人PDA是一种安全、简便、有效、创伤小、恢复快的方法。     

经皮肺动脉瓣成形术治疗肺动脉瓣狭窄的临床分析

目的:探讨应用Inouc球囊经皮肺动脉瓣成形术(PBPV)治疗肺动脉瓣狭窄(PVS)的临床疗效。方法:PVS 患者18例,采用PBPV进行治疗,并以超声多普勒评价其疗效。结果:18例行PBPV患者术后即刻右心室收缩压由 (101．4±28．2)mmHg降至(48．5±16．7)mmHg(P<0．01)。右房压由(16．9±7．5)mmHg降至(9．8±4．3)mmHg (P<0．05),肺动脉压由(15．2±3．1)mmHg升至(23．1±5．6)mmHg(P<0．05),肺动脉与右心室跨瓣压差 (△P)由(76．5±25)mm Hg降至(21．7±12．2)mmHg(P<0．01)。多普勒超声随访:术后3个月跨瓣压差较术后即刻进一步显著下降(P<0．05)。结论:经皮球囊肺动脉成形术治疗肺动脉瓣狭窄安全有效。     

大孔型房间隔缺损封堵治疗的疗效和安全性

目的探讨经导管介入治疗大孔型房间隔缺损(ASD)的疗效和安全性。方法选择经胸超声心动图确诊的大孔房间隔缺损患者46例,年龄8~71岁,平均37.6岁。术前超声心动图检查ASD最大直经25~38(30±8)mm,术前心功能(NYHA分级)Ⅱ级15例,Ⅲ级5例,其中肺动脉平均压力>25mmHg者28例,封堵前肺动脉压力(32±8.2)mmHg。所有患者均在局麻下,应用X光透视,和经胸心脏超声引导下经导管置入国产封堵器,封堵ASD,对部分ASD残端薄弱者采用“肺静脉法”操作技术完成封堵。结果44例封堵成功,技术成功率95.6%。选择封堵器直经为30~42mm,封堵后肺动脉压降低至(18.4±5.8)mmHg。术中未发生任何重要并发症,无急诊手术病例。失败2例患者ASD伸展径分别为36mm和38mm,缺损后缘缺乏有效房隔组织。术后即刻超声显示6例仍存在微量至少量残余分流,分流束直径小于4mm;术后6月超声心动图检查时无1例残余分流,房间隔封堵器位置稳定。术后6~38个月随访,右心房、右心室缩小,心功能明显改善。无封堵器相关并发症。结论国产封堵器介入治疗大孔房间隔缺损具有操作简便、安全、费用低、技术成功率高及封堵效果好等优点。     

经导管同期治疗复合型先天性心脏病的疗效和安全性

目的:探讨经导管介入同期治疗复合型先天性心脏病的可行性、方法及疗效.方法:13例患者,男5例,女8例.其中房间隔缺损(ASD)合并肺动脉瓣狭窄6例,ASD合并动脉导管未闭(PDA)4例,ASD合并膜部室间隔缺损2例,PDA合并肺动脉瓣狭窄1例.ASD合并其他畸形的患者,均先治疗其他畸形,最后行ASD封堵.PDA合并肺动脉瓣狭窄者,先行肺动脉瓣狭窄球囊扩张术,最后封堵PDA.结果:13例患者均经导管一次治疗成功.ASD合并肺动脉瓣狭窄6例,跨肺动脉瓣压差由术前平均(138.3±41.4)mmHg下降到术后平均(12.0±5.6)mmHg,有显著性差异(P＜0.01).所用ASD封堵器直径为8～24 mm.ASD合并PDA4例,PDA最窄径2～5 mm,封堵器直径为6～8 mm;ASD封堵器直径为8～28 mm.ASD合并膜部室间隔缺损2例,室间隔缺损直径分别为3.5 mm和5.0 mm,用直径6 mm和8 mm的双盘状室间隔缺损封堵器封堵成功,所用ASD封堵器的直径为12 mm和18 mm.1例PDA合并轻度肺动脉瓣狭窄,用聚乙烯球囊扩张、PDA用4 mm封堵器治疗成功.结论:经导管介入同期治疗复合型先天性心脏病具有技术上的可行性、安全性和良好的治疗效果.     

介入封堵术在老年继发孔型房间隔缺损患者中的临床应用

目的观察老年继发孔型房间隔缺损(ASD)患者进行介入封堵术的中、远期疗效和安全性。方法老年继发孔型ASD患者206例,缺损8～38(26.5±8.1)mm。封堵术前、术后行右心导管检测肺动脉压、右心室压,随访6个月,评价心功能(NYHA)改善情况。结果成功封堵203例,成功率98.5%。封堵器直径12～42(31.5±7.3)mm。与封堵术前比较,患者封堵术后肺动脉收缩压、右心室平均压明显下降(P<0.05,P<0.01);3～6个月随访时,患者右心室容积缩小、LVEF升高、心功能改善明显。术后心包积液1例(0.5%);即刻残余分流10例(4.9%);术后出现心律失常30例(14.8%)、出现急性心功能不全16例(7.9%)。6个月随访,患者均未发现有残余分流、脱落、栓塞。结论老年继发孔型ASD患者行介入封堵治疗中、远期相对安全、有效。     

经导管封堵主动脉窦瘤破入右心房的临床疗效及长期随访结果

目的评价经导管封堵主动脉窦瘤破入右心房的临床安全性、有效性以及长期随访结果。方法选取2006年1月至2013年4月于沈阳军区总医院先心病内科住院并应用国产动脉导管未闭封堵器或细腰型室间隔缺损封堵器经导管成功封堵的主动脉窦瘤破入右心房患者,封堵术后进行长期随访。结果共入选15例患者,其中男11例,年龄21~48(35.50±8.79)岁,体质量为54~90(71.9±13.47)kg。15例患者中右冠状窦破裂11例(11/15),无冠状窦破裂4例(4/15);术前NYHA心功能分级为(2.56±0.63)级;术前测量肺动脉平均压为13.33~41.67(25.38±8.21)mmHg(1 mmHg=0.133 k Pa),Qp/Qs比值为1.34~2.81(1.93±0.39);主动脉造影测量破口直径为4~10(6.42±1.92)mm。6例采用国产动脉导管未闭封堵器,9例采用细腰型室间隔缺损封堵器。封堵后肺动脉平均压显著低于术前平均压[(15.24±4.75)mmHg比(25.38±8.21)mmHg,P0.05];手术过程中均未发生严重并发症,手术成功率为100%。术后末次随访患者心胸比值、右心房内径、右心室内径、左心房内径、肺动脉直径以及左心室舒张末期内径较术前均显著降低,差异均有统计学意义(均P0.01)。所有患者随访35~132(78.6±28.57)个月,末次随访时NYHA心功能分级分布在Ⅰ~Ⅱ级,与术前比较,心功能均显著改善(P0.01)。随访期间所有患者均未出现感染性心内膜炎、封堵器移位、严重残余分流、血栓形成、严重主动脉瓣反流、心肌梗死、严重心律失常、死亡等严重并发症。结论应用国产细腰型室间隔缺损封堵器及动脉导管未闭封堵器封堵主动脉窦瘤破入右心房安全、有效,且长期随访结果良好。     

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.     

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.     

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.     

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。     

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     

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。     

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.