老年慢性充血性心力衰竭贫血情况调查

目的:探讨老年人慢性充血性心衰(CHF)患者贫血的发生率,观察血色素(Hb)与患者心功能分级的关系,贫血对住院期间心力衰竭死亡率的影响。方法:2005年12月至2006年6月220例老年(年龄≥70岁)CHF住院患者,男性86例,女性134例,平均年龄(75±5.6)岁。纽约心脏病协会(NYHA)心功能分级Ⅱ级55例(25%),Ⅲ级99例(45%)Ⅳ级,66例(30%),贫血定义男性Hb<12.08g/dl,女性<11.0g/dl,统计老年CHF患者贫血的发生率,比较贫血组和非贫血组心功能分级情况,贫血组和非贫血组住院期间死亡率。结果:220例中有90例并发贫血(除外继发性贫血,如肾功能不全,肿瘤,血液系统疾病等)发病率为40.1%(90/220),贫血程度随心功能恶化而相对严重。NYHAⅡ级Hb(13.4±2.64)g/dl,Ⅲ级Hb(12.6±1.96)g/dl,Ⅳ级Hb(9.4±2.84)g/dl,贫血组住院死亡率24.4%(22/90),非贫血组住院死亡率11.5%(P<0.001)。结论:老年慢性心力衰竭患者贫血发病率较高,贫血程度和心力衰竭严重程度相关。随心力衰竭分级增加贫血程度加重。贫血是老年慢性心衰常见并发症,且和老年心衰死亡率增加有一定关系。     

贫血对慢性心力衰竭患者住院期间死亡的影响

目的:了解慢性心力衰竭(CHF)患者贫血的发生率及其对住院期间死亡的影响。方法:收集2003-01-2008-06在我院住院的CHF患者的临床资料进行回顾性分析,根据患者血红蛋白(Hb)水平分为Hb正常组、轻度贫血组以及中重度贫血组3组。结果:贫血在CHF患者的发生率为32·5%;住院期间死亡患者的Hb、RBC均明显低于好转的患者(P0·01),贫血患者在住院期间的死亡率明显高于无贫血的患者(P0·01),以二分类Logistic回归住院期间死亡的危险因素进行分析得出:贫血的偏回归系数为1·296(P=0·039),优势比(OR)为3·655(95%CI:1·069~12·499);对于心功能NYHAⅢ~Ⅳ级的CHF患者,Hb的偏回归系数为-0·073(P=0·041),OR为0·93(95%CI:0·864~0·995)。结论:CHF患者贫血的发生率较高,贫血是CHF患者住院期间死亡的独立危险因素,Hb降低增加心功能Ⅲ~Ⅳ级的CHF患者住院期间的死亡。     

老年慢性心力衰竭患者红细胞分布宽度的变化及临床意义

目的探讨老年慢性心力衰竭(CHF)患者血红细胞分布宽度(RDW)与纽约心脏病协会(NYHA)心功能分级的关系及住院死亡风险的相关性。方法选择125例住院老年CHF患者作为CHF组,按照NYHA心功能分级分为Ⅱ级组47例,Ⅲ级组41例,Ⅳ级组37例;对照组选择同期住院心功能正常者47例。测定血RDW、红细胞计数(RBC)、血红蛋白(HB)、平均红细胞体积(MCV)及左室射血分数(LVEF),对比分析2组一般资料及各项检测指标。结果 CHF组高血压、糖尿病患病率高于对照组(P0.05或0.01),LVEF低于对照组(P0.05)。心功能Ⅱ级组RDW与对照组比较无统计学差异(P0.05),心功能Ⅲ级组、Ⅳ级组RDW较对照组明显升高(P0.05)。心功能Ⅳ级组RDW高于心功能Ⅲ级组(P0.05)。与对照组比较,心功能Ⅲ级组、Ⅳ级组RBC显著下降(P0.05),HB及MCV无明显变化。心功能Ⅲ级组和Ⅳ级组院内共死亡18例,Logistic回归分析示RDW是CHF的独立影响因素。结论老年CHF患者RDW高于正常对照组,且随NYHA分级的增加RDW水平逐渐升高,与患者住院死亡密切相关,可能是老年CHF患者死亡危险因素。     

慢性心力衰竭患者血红蛋白水平对预后的影响

目的探讨慢性心力衰竭患者血红蛋白(Hb)水平对预后的影响。方法对在1998年1月1日~2002年12月31日期间住院治疗且资料完整的192例慢性心衰患者进行回顾性分析,随访时程为两年。对不同组患者的Hb浓度、血清肌酐浓度、贫血发生率及随访期间的心血管事件等进行比较。结果Hb浓度随着NYHA分级的升高而降低〔Hb浓度在NYHAⅡ级为(13954±2155)g/L,NYHAⅢ级(13055±2212)g/L,NYHAⅣ级(12996±1905)g/L,P<005〕;贫血发生率随着NYHA分级的升高而升高(NYHAⅡ级1667%,NYHAⅢ级2159%,NYHAⅣ级2647%,P<005);与非贫血组比较,贫血组患者的病死率、心衰加重、住院次数、住院天数明显增加(P<005)。结论随心功能下降血红蛋白水平降低,贫血发生率增加;血红蛋白水平越低,预后越差。     

老年患者充血性心力衰竭的危险因素分析

目的:分析老年患者充血性心力衰竭(CHF)的危险因素。方法:788例年龄60岁的老年住院患者,其中162例心功能NYHA分级Ⅰ级且左心室射血分数LVEF50%为对照组,其余626例心功能NYHA分级Ⅱ~Ⅳ级且LVEF≤40%患者为CHF组。比较两组临床特征和实验室指标,并采用多因素Logistic逐步分析,探讨老年患者CHF的独立危险因素。结果:与对照组比较,CHF组冠心病、高血压病和快速心房颤动比例显著增高,收缩压、血清尿酸、肌酐、高敏C反应蛋白(hs-CRP)、N-末端B型利钠肽原(NT-proBNP)水平也增高,且增高程度随心功能恶化而加重;但CHF组血红蛋白水平降低。CHF组血管紧张素转化酶抑制剂、血管紧张素受体拮抗剂、地高辛、β受体阻滞剂的使用率高于对照组(P0.01)。多因素Logistic逐步回归分析显示,快速心房颤动、高尿酸血症、贫血、肾功能不全、hs-CRP和NT-proBNP增高是老年患者发生CHF的独立危险因素。结论:老年患者CHF受多个危险因素的影响。血清肌酐、hs-CRP和NT-proBNP水平可能部分反映老年CHF患者的病情严重性。     

慢性心力衰竭患者N端脑钠肽前体、内皮素与心功能的关系

目的探讨慢性心力衰竭(心衰,CHF)患者N端脑钠肽前体(NT-proBNP)、内皮素(ET)水平与心功能的关系。方法入选56例CHF患者作为研究对象,29例心功能正常者作为对照组。心衰患者按照NYHA分级分为心功能Ⅱ级、Ⅲ级、Ⅳ级3个亚组,分别测定患者NT-proBNP、ET水平,同时用心脏彩色多普勒超声心动仪测定左室射血分数(LVEF)和左室舒张末期内径(LVDD)并进行组间比较及相关性分析。结果对照组及CHF心功能Ⅱ级、Ⅲ级、Ⅳ级亚组的患者NT-proBNP水平分别为(336.24±41.25)ng/ml、(1761.35±21.43)ng/ml、(2693.45±41.54)ng/ml、(3161.26±67.56)ng/ml,ET水平分别为(19.89±11.35)ng/L、(48.60±21.25)ng/L、(61.56±31.68)ng/L、(161.67±46.56)ng/L。对照组患者及CHF心功能Ⅱ级组、Ⅲ级组、Ⅳ级组患者血浆NT-proBNP、ET水平呈逐渐增高趋势,差异具有显著统计学意义(P0.01)。除心功能Ⅱ级组与心功能Ⅲ级组间ET与LVEF水平比较无统计学差异(P0.051),其余各组间NT-proBNP、ET水平及LVEF、LVDD水平比较,均有显著统计学差异(P均0.01)。NT-proBNP与心功能分级呈正相关(r=0.769,P0.05),与LVDD呈正相关(r=0.606,P0.05),与LVEF呈负相关(r=-0.656,P0.05)。ET水平与心功能分级呈正相关(r=0.357,P0.05),与LVDD呈正相关(r=0.265,P0.05),与LVEF呈负相关(r=-0.274,P0.05)。结论 CHF患者NT-proBNP与ET水平随心力衰竭程度的加重而相应升高,与心功能分级有良好的相关性,对心力衰竭患者心力衰竭严重程度及预后的评价有意义。     

老年慢性心力衰竭患者贫血与心功能关系的探讨

目的研究老年慢性心力衰竭(CHF)患者中血红蛋白(Hb)水平变化与心功能的关系。方法对入选的286例年龄>60岁的CHF患者(CHF组)行临床、实验室和超声心动图检查,并进行心功能分级(NYHA);CHF组患者按Hb水平又分为贫血组(136例)和非贫血组(150例);根据NYHA分为轻、中度心力衰竭患者(203例),重度心力衰竭患者(83例);同时选择98例健康体检老年人为对照组,分别比较各组间不同性别血液学参数、血尿素、肌酐(Cr)、LVFF、左心室舒张末期内径(LVEDD)、贫血发生率、病死率,并采用改良简化的MDRD方程计算肾小球滤过率(GFR)。结果与对照组比较,CHF组男、女性患者的Hb、红细胞比容、LVEF和GFR均明显降低(P<0.01),尿素、Cr和LVEDD均明显升高(P<0.05,P<0.01);与轻、中度心力衰竭患者比较,重度心力衰竭患者Hb、红细胞比容、LVEF和GFR均明显降低,Cr、LVEDD、贫血发生率、病死率逐步升高(P<0.05,P<0.01)。CHF患者的Hb、LVEF均与Cr呈负相关,而与GFR呈正相关(P<0.01),Hb与LVEF呈正相关(P<0.01)。结论老年CHF男、女性患者常伴有贫血和肾功能损害,贫血和肾功能损害的程度均与CHF的严重程度呈正相关,贫血、肾功能损害均使CHF患者死亡危险性增高。     

贫血对舒张性心力衰竭患者心功能的影响(英文)

目的:探讨舒张性心力衰竭(DHF)患者血红蛋白(Hb)含量的变化,贫血与左室功能的关系及对预后的影响。方法:176例DHF患者按照NYHA分级分为:Ⅱ级78例,Ⅲ级50例,Ⅳ级48例,分析各组Hb水平和贫血患病率。按照贫血诊断标准患者被分为贫血组(58例,占33.0%)与非贫血组(118例,占67.0),对两组患者左室舒张功能,随访期间的死亡率及再住院率进行比较分析。结果:贫血组随心功能分级(Ⅱ级~Ⅳ级)增加,Hb水平呈下降趋势[(130±6)g/L比(108±4)g/L比(96±12)g/L],而贫血的患病率逐渐增加(8.97%比36.0%比68.8%),P均<0.05。与非贫血组相比,贫血组的冠心病患者比例(55.1%比65.5%)、肌酐[(87.6±39.2)μmol/L比(113.7±59.8)μmol/L]、N末端B型利钠肽原[NT-proBNP,(578.0±136.7)pg/ml比(886.0±174.8)pg/ml]水平明显升高,舒张早期峰速减速时间明显增加[(137±15)ms比(196±13)ms],二尖瓣舒张早期/晚期峰值流速比值[E/A,(0.87±0.32)比(0.62±0.29)]明显减小(P均<0.05)。随访期间与非贫血组比较,贫血组的死亡率(9.3%比20.7%)、再住院率(18.6%比32.8%)明显上升(P均<0.05)。结论:DHF患者常伴有贫血,随着心衰严重程度的加重其贫血发病率增加,贫血可能加重心脏舒张功能不全,合并贫血的DHF患者其死亡率及再住院率增加。     

贫血增加慢性心力衰竭患者死亡率

目的调查贫血在慢性心力衰竭(CHF)住院患者中发生率,以及与CHF患者死亡率的关系。方法收集2007年1月1日至2009年12月31日在北京协和医院心内科住院,年龄≥21岁,临床诊断为心力衰竭,且左心室射血分数(LVEF)≤45%的缺血性(心肌梗死后至少40 d以上)或非缺血性心肌病患者进行回顾性研究,根据是否贫血[血红蛋白<120 g/L(男性)或110 g/L(女性)]分为两组,贫血组和对照组,并进行电话随访。结果共242例患者入选,对197例进行随访,14例(7.1%)失访,经过平均(20±9)个月(2～41个月)随访,共36例(20%)发生全因死亡,包括贫血组13例(34%)和对照组23例(16%)(χ2=6.415,P=0.011)。结论贫血在CHF住院患者中常见,贫血增加CHF死亡率,因此在积极抗心力衰竭治疗同时应高度重视贫血的纠正,以更好地改善CHF患者预后。     

内源性促红细胞生成素对慢性心力衰竭患者预后的影响

目的了解内源性促红细胞生成素(EPO)对慢性心力衰竭(CHF)患者预后的判定价值。方法选择住院的CHF患者115例,以患者是否存活分为死亡组55例,存活组60例。另选同期住院的年龄、性别相匹配的非CHF患者67例为对照组,以便建立logEPO和血红蛋白(Hb)的回归方程。对CHF患者进行全因死亡和因心力衰竭再次入院的随访观察,测定血EPO,并进行分析。结果与存活组比较,死亡组高龄患者多、心功能(NYHA)Ⅱ级比例低、Hb降低和B型钠尿肽(BNP)水平升高(P<0.01)。Kaplan-Meier生存曲线显示,贫血的CHF患者病死率增高(RR=2.50,95%CI:1.38～4.54,P=0.002)。ROC曲线评估EPO和BNP预测CHF患者死亡的最佳界值分别为44.4 U/L和752 ug/L(P=0.036,=0.000)。年龄、Hb、BNP和NYHA对CHF患者全因死亡有独立预测价值;而男性、BNP和Hb水平对因心力衰竭再次入院有独立预测价值。贫血的CHF患者EPO是独立于Hb的全因死亡的强预测指标(RR=2.86,95%CI:1.18～6.94,P=0.020)。结论贫血是CHF患者不良预后的独立预测因素。EPO是贫血CHF患者全因死亡的独立预测指标。     

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.