54例胸主动脉腔内修复术治疗B型主动脉壁内血肿10年生存分析

目的：评估胸主动脉腔内修复术（TEVAR）方式治疗B型主动脉壁内血肿（IMH的临床效果和风险。方法：选取河南省人民医院血管外科2011年12月至2021年12月期间收治的54例B型IMH行TEVAR患者作为研究对象，对患者的临床资料进行回顾性分析。结果：TEVAR治疗54例B型IMH，技术成功率100%。其中单纯行TEVAR36例，左锁骨下动脉（LSA）开口部分覆盖6例，LSA开口全部覆盖2例,LSA重建10例。围术期1例逆撕A型主动脉夹层行外科手术，1例出现脑梗死给予保守治疗，1例因出现新发破口再次干预行TEVAR，所有患者全部存活出院。随访13～112个月，平均随访（63±10.5）个月，失访3例，有效随访率94%。随访患者共6例死亡，2例患者再干预手术，K-M生存曲线显示10年总存活率79.8%。结论：B型IMH行TEVAR技术成功率高，创伤小，恢复快，远期预后好。然而，围术期有逆撕A型主动脉夹层及脑梗死等风险。对于血肿累及LSA开口导致近端锚定区不足的患者，尽可能选择个体化方案重建LSA，部分覆盖或者完全覆盖LSA开口一定要慎重。     

腔内修复术与药物治疗胸降主动脉穿透性溃疡近远期疗效分析

目的 对比评价腔内修复术(EVAR)与药物治疗（MT）对胸降主动脉穿透性溃疡(PAU)的近、远期疗效。方法 观察2006年3月~2014年3月住院的85例PAU患者，根据治疗方式分为EVAR组（47例）和MT组（38例），EVAR组在强化药物治疗基础上行EVAR治疗，MT组单纯行药物强化治疗，随访观察2组间近期、远期的肢体缺血、截瘫、肾功能衰竭、脑卒中、新发主动脉夹层、死亡等不良事件的发生情况。结果 EVAR组患者47例手术均成功，术中无内漏、支架移位、主动脉破裂死亡及脑卒中等发生。首次入院至30 d随访，2组随访率均为100%，2组无截瘫、脑卒中及死亡事件发生。EVAR组肢体缺血、肾功能衰竭的发生率均略低于MT组，但差异均未达到显著性水平（0 vs. 10%，2% vs. 5%）。MT组新发主动脉夹层发生率显著高于EVAR组（16% vs. 0%，P<0.01）。2组远期随访时间、随访率差异无统计学意义〔（34±22）个月 vs.（32±23）个月，87% vs. 82%〕。远期随访2组间均无截瘫发生，MT组肢体缺血、肾功能衰竭的发生率均略高于EVAR组，但差异均未达到显著水平（16% vs. 2%;13% vs. 5%）。EVAR组总的病死率及主动脉破裂病死率均略低于MT组，但2组间差异均未达到显著水平（5% vs. 13%；2% vs. 6%）。结论 与MT相比，EVAR治疗PUA , 可降低近、远期主动脉夹层的发生率。     

Stanford B型主动脉夹层腔内修复术的手术时机对预后的影响

目的：探讨Stanford B型主动脉夹层（type B aortic dissection,TBAD）胸主动脉腔内修复（thoracic endovascular aortic repair, TEVAR）术的手术时机对预后的影响。方法：回顾性分析2015年6月到2020年6月，在单中心行TEVAR治疗的TBAD患者的临床资料，收集患者一般基线资料：住院号、姓名、性别、年龄、吸烟史、饮酒史、既往疾病史（高血压、冠心病、糖尿病、高脂血症）。围术期及随访期死亡，围术期及随访期并发症：内漏、覆膜支架移位、覆膜支架远端新发夹层、逆撕A型夹层、脑卒中、脊髓缺血、急性肾损伤等。结果：共纳入217例TBAD患者，其中急性期（A组）患者141例，平均年龄（60.1±12.8）岁；非急性期（B组）患者76例，平均年龄（63.5±11.4）岁。男性患者160例，女性患者57例。两组患者在术后30d死亡率（2.8%vs. 2.6%），主动脉相关性死亡率（2.8%vs. 2.6%），主要并发症发生率（14.9%vs. 14.5%）；随访期死亡率（5.8%vs. 10.8%），主动脉相关性死亡率（3.6%vs...     

急性主动脉夹层并下肢动脉严重缺血患者的治疗分析

目的探讨急性主动脉夹层合并下肢动脉严重缺血患者的治疗效果及安全性。方法收入2013年10月至2015年1月沈阳军区总医院收治的急性主动脉夹层合并下肢动脉严重缺血患者8例,均为男性,年龄(43.6±8.4)岁,分析其治疗策略及疗效。结果 1例Stanford A型主动脉夹层患者合并主动脉瓣关闭不全,行主动脉瓣置换+人工支架象鼻手术;6例Stanford B型主动脉夹层患者行胸主动脉腔内修复术(thoracic endovascular aortic repair,TEVAR);1例Stanford B型主动脉夹层患者于术前急性肾功能衰竭死亡。Stanford A型主动脉夹层患者于外科术后第4天因多脏器功能衰竭死亡;1例Stanford B型主动脉夹层于TEVAR后次日因急性肾衰竭死亡;余5例顺利出院。术后随访时间(11±5)个月。随访期间3例均病情平稳,血压控制良好,患侧下肢疼痛及麻木感消失,术后恢复良好,无截瘫等事件发生。1例右下肢活动仍受限,1例虽病情相对平稳,但活动后仍存在下肢疼痛症状,于术后6个月植入微创腹主动脉覆膜支架1枚,右髂总动脉至髂外动脉植入金属裸支架1枚。术后患者病情平稳,活动后下肢疼痛症状消失,术后3个月复查主动脉增强计算机断层扫描(CT),主动脉夹层愈合良好,双髂动脉及下肢动脉血流通畅,肾动脉可见一小破口。结论急性主动脉夹层合并下肢动脉严重缺血患者病情危重,围术期病死率高,需加强围术期管理,TEVAR后远期疗效良好。     

胸主动脉腔内修复术治疗Stanford B型主动脉夹层

目的 总结胸主动脉腔内修复术（thoracic endovascular aortic repair,TEVAR）治疗Stanford B型主动脉夹层的临床经验.方法 回顾性分析134例Stanford B型主动脉夹层患者的临床资料,分析并发症发生的原因及随访近、远期效果.结果 术前死亡4例,未手术1例,施行TEVAR 129例,手术操作均成功,部分封堵左锁骨下动脉27例（20.9％）,完全封闭左锁骨下动脉12例（9.3％）;Ⅰ型内漏13例（10.1％）,夹层逆剥为Stanford A型1例,低氧血症23例（17.8％）,肾功能衰竭需血液滤过9例（7.1％）,术后精神症状37例（28.7％）,脑梗死3例.随访2个月～5年,随访110例,随访率85.7％,1例术后1年和1.5年出现支架远端夹层,两次手术植入覆膜支架,部分封闭了腹腔干动脉,1例术后2个月时因肠梗阻在外院行手术治疗,1例术后4年时支架远端发生夹层破裂死亡,1例术后3个月突然死亡.Ⅰ型内漏消失11例,持续存在2例.结论 急诊TEVAR治疗Stanford B型主动脉夹层安全、可靠,近期效果良好,加强并发症的防治,可进一步改善临床效果.     

主动脉腔内修复术在复杂B型夹层患者中应用的围术期效果及长期生存率分析

目的:分析主动脉腔内修复术(TEVAR)在复杂B型夹层患者中应用的围术期效果与长期生存状况。方法:收集自2001年6月至2015年3月,在我院大血管中心行TEVAR治疗的复杂B型夹层患者的基本资料、围术期资料并进行随访。将所得的数据进行分析。结果:共有179例患者诊断为复杂B型夹层并接受TEVAR治疗,其中男性162例(90.5%),女性17例(9.5%),平均年龄(51.3±11.6)岁。围术期死亡7例,病死率3.9%,术后肢体缺血4例(2.2%),胃肠缺血3例(1.7%),肾衰竭3例(1.7%),左上肢动脉急性血栓形成1例(0.6%),股动脉穿刺口局限性夹层形成1例(0.6%),逆行性A型夹层形成1例(0.6%)。无围术期脑梗死、截瘫发生。TEVAR术后5年,10年生存率分别为95.8%,82.1%,5年,10年再次干预率分别为3.7%,5.4%。结论:本研究呈现了TEVAR在复杂B型夹层患者中应用的围术期并发症及5年,10年生存与再干预情况。术后仍持续存在的灌注不良是患者死亡的主要原因,围术期应及时识别灌注不良的症状并及时恢复灌注以减少并发症和术后死亡的发生。     

急性Stanford B型主动脉夹层腔内修复治疗的疗效评价

目的:评价腔内修复术（TEVAR）治疗急性Stanford B型主动脉夹层的中、远期疗效。方法: 2001年12月～2009年6月,对急性Stanford B型主动脉夹层进行血管腔内支架植入治疗患者288（男237,女51）例,年龄21～79（平均51.2）岁。局部或全身麻醉,在 X线透视下将支架型人工血管经股动脉放置在主动脉夹层第1裂口位置,实现腔内修复。应用多排CT等技术进行38个月（6～102月）的随访,观察假腔血栓形成情况、有无内漏、血流动力学变化、移植物位置及形态、内脏动脉供血等情况,评估该方法的安全性及有效性。结果: 全组患者无移植物错放、移位、瘤体破裂、中转手术和截瘫等并发症。围术期死亡6例,分别为:腹腔脏器缺血/再灌注损伤2例、升主动脉逆行夹层1例、夹层破裂1例、心肌梗死1例及死亡原因不明1例。住院期间并发症发生率25.3%,包括术后即刻内漏、发热、肾功能不全、切口感染、肺炎、神经系统并发症、心功能不全、左肱动脉假性动脉瘤、截肢等。随访中共有7例死亡(2.4%),4例患者行二次TEVAR术后治愈。Kaplan-Meier生存曲线显示5年累积生存率达96%。结论: TEVAR术是治疗急性Stanford B型主动脉夹层的一种有效方法,中期疗效满意,患者远期生存状况良好。     

胸主动脉腔内修复体外开窗与选择性隔绝左锁骨下动脉的前瞻性队列研究

【摘要】目的 探讨胸主动脉腔内修复（TEVAR）体外开窗与选择性隔绝左锁骨下动脉的安全性和有效性。 方法 前瞻性队列研究分析 2012 年 9 月至 2017 年 10 月十堰市太和医院心脏大血管外科收治的 117 例胸主动脉病变患者的临床资料,根据左锁骨下动脉处理方式不同分为直接选择性隔绝LSA腔内修复组（endovascular exclusion,EE）和体外开窗LSA腔内修复组（invitro fenestration,IF）,比较两组患者的治疗效果和3年随访结果。结果 围术期结果上,EE组手术时间( 62.0 ± 5.4 )min短于IF组,脑梗塞、左上肢缺血发生率分别为7.14%（4/56）、10.71 % ( 6 / 56 )高于IF组,差异有统计学意义（ P 均＜ 0.05 ）;EE组的内漏、脊髓缺血、术后 30 天病死、支架覆盖T10发生率分别为 5.36 % （ 3 / 56 ）、 5.36 %（ 3 / 56 ）、 1.79 % （ 1 / 56 ）、 12.50 % ( 7 / 56 )与IF组相比,差异无统计学意义（ P 均＞ 0.05 ）。随访结果方面,生存出院患者 116 例,失访 12 例,持续随访 104 例,随访率 89.7 ％（ 104 / 116 ）。随访时间 36~60 个月,平均（ 38.1 ± 3.2 ）月。3 年随访结果显示EE组未增加主动脉源性死亡,但脑梗塞和上肢缺血发生率高于IF组。EE组、IF组随访3年累计生存率分别为 82.23 % 和 85.19 % 。两组间 3 年生存曲线总体比较差异无统计学意义（X2=0.055, P=0.814 ）。 结论 选择性隔绝左锁骨下动脉腔内修复可缩短手术时间,有效延长锚定区,降低内漏发生,但增加脑梗塞、脊髓缺血、左上肢缺血发生风险,体外开窗重建左锁骨下动脉腔内修复手术并发症低,两组中期随访结果满意,远期尚需进一步评估。     

胸主动脉钝性外伤的腔内修复治疗

目的 探讨腔内修复技术在治疗胸主动脉钝性外伤中的可行性和安全性.方法 回顾分析2010年2月至2013年12月期间7例胸主动脉钝性外伤患者的临床资料.术前CTA及术中造影评估病变,回顾术中技术成功率,死亡及截瘫等主要并发症的发生率.术后CTA随访明确有无内漏、支架移位等情况.结果 所有创伤都累及主动脉峡部,包括Stanford B型夹层1例、降主动脉假性动脉瘤6例.全部患者均接受覆膜支架腔内修复治疗,其中1例先行左-右锁骨下动脉转流术.术中6例部分或全部覆盖左锁骨下动脉开口.所有手术患者均获得技术成功,无死亡及截瘫发生.术后随访时间2～28个月,无左上肢缺血症状及神经系统并发症,支架无内漏及移位.结论 腔内修复治疗胸主动脉夹层安全、有效,可行性高.     

B型主动脉夹层介入治疗部分封堵左锁骨下动脉的影响探讨

目的观察B型主动脉夹层患者通过腔内修复手术中部分封堵左锁骨下动脉后的疗效。方法选择自2009年1月~2016年1月于汉中市人民医院接诊的35例通过部分封堵左锁骨下动脉治疗B型主动脉夹层患者的临床及术后半年随访资料进行回顾性分析,评估手术相关的并发症发生情况。结果 35例患者中有34例植入覆膜支架取得成功,未成功患者是主动脉迂曲导致,手术用时(53.8±5.4)min,住院时间为(6.0±1.7)d;对患者进行半年的随访,结果显示出,34例部分封堵左锁骨下动脉的患者中,3例出现左上肢缺血症,1例产生一过性眩晕及脑缺血发作,其他患者在术后随访中并未发生任何不良症状。结论在B型主动脉夹层患者中应用部分封堵左锁骨下动脉技术操作简单便捷,在B型主动脉夹层的治疗方式中已成为首选,但还需根据Willis环及左椎动脉情况做适当选择。     

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。     

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。     

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。     

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.