肺癌患者血清和胸腔积液膜联蛋白A2水平改变及其临床意义研究

目的探讨肺癌患者血清和胸腔积液膜联蛋白A2(ANXA2)水平改变及其临床意义。方法连续性收录60例肺癌患者,以及40例肺部良性病变患者。检测血清和胸腔积液中ANXA2水平改变,分析其与肿瘤分期、淋巴结以及远处组织转移情况等相关性。结果肺癌组中血清及胸腔积液内ANXA2(血清:32.3±14.0 ng/m Lvs.16.8±6.5 ng/m L,P0.05;胸腔积液:66.8±14.7 ng/m L vs.25.2±12.6 ng/m L,P0.05)水平明显高于良性肺病组。肺癌患者胸腔积液中ANXA2浓度高于血清浓度(32.3±14.0 ng/m L vs.76.8±14.7 ng/m L,P0.05)。TNM分期Ⅰ-Ⅱ期患者血清及胸腔积液ANXA2明显低于Ⅲ-Ⅳ期患者(血清:29.1±12.1 ng/m L vs.34.7±16.2 ng/m L,P0.05;胸腔积液:61.6±18.8 ng/m L vs.78.5±11.7 ng/m L,P0.05);有淋巴结转移患者血清及胸腔积液ANXA2明显高于无淋巴结转移患者(血清:35.2±16.1ng/m L vs.30.5±11.3 ng/m L,P0.05;胸腔积液:88.6±20.7 ng/m L vs.59.3±11.5 ng/m L,P0.05);有远处转移患者血清及胸腔积液ANXA2明显高于无远处转移患者(血清:37.4±9.6ng/m L vs.29.1±6.8 ng/m L,P0.05;胸腔积液:82.2±12.3ng/m L vs.65.9±18.7 ng/m L,P0.05)。血清ANXA2诊断肺癌的AUC为0.712,cut-off值为40.2 ng/m L;而胸腔积液ANXA2水平诊断肺癌的AUC为0.822,cut-off值为78.2 ng/m L。血清和胸腔积液ANXA2水平与肺癌呈正相关(血清:r=0.706,P0.05;胸腔积液:r=0.812,P0.05)。结论肺癌患者血清和胸腔积液中ANXA2水平明显上升,对于肺疾病合并胸腔积液者,血清及胸水ANXA2测定,有助于肺癌鉴别诊断和分期。     

HPA和MMP9对非小细胞肺癌患者临床预后评价的意义研究

目的检测非小细胞肺癌(NSCLC)患者血清HPA和MMP9水平,分析其与NSCLC患者淋巴结转移以及预后的关系。方法选取80例NSCLC患者和30例健康对照,采用酶联免疫法检测HPA和MMP9的血清水平,分析HPA和MMP9与患者临床病理特征的关系,通过受试者工作曲线分析血清HPA和MMP9用于判断NSCLC患者是否发生淋巴结转移的可行性,通过Kaplan-Meier法进行分析HPA和MMP9预测病人预后的临床意义。结果 NSCLC患者血清HPA和MMP9值均高于健康对照组;血清HPA与淋巴结转移、远处转移有关,血清MMP9值与TNM分期、淋巴结转移、远处转移有关;血清HPA和MMP9用于预测NSCLC患者淋巴结转移情况的曲线下面积分别为0.732和0.785;NSCLC患者血清HPA和MMP9越高,患者预后越差。结论血清HPA和MMP9均可用于确定NSCLC患者是否发生淋巴结转移,并可用于评估病人预后。     

血清胸腺嘧啶核苷激酶1水平与肺癌患者临床病理特征及预后的关系

目的探讨肺癌患者血清胸腺嘧啶核苷激酶(TK)1与肺癌患者临床病理特征及预后的关系。方法肺癌患者80例为肺癌组,取66例健康者为对照组,采用化学发光法检测TK1表达,并收集患者临床病理特征与1、3年生存情况。结果肺癌患者中TK1阳性率为40.00%(32/80),显著高于健康对照组的13.64%(9/66)(P0.05),肺癌患者TK1阳性率在性别、吸烟史、淋巴结转移及病理类型上未见统计学差异,而与远处转移及TMN分期有关(P0.05);肺癌TK1阳性与阴性患者在1年生存率上未见统计学差异(P0.05),但3年生存率阳性患者明显低于阴性患者(P0.05)。结论血清TK1在肺癌患者中高表达,并与患者发生远处转移及TMN分期密切相关,且预后生存率低。因此,血清TK1可作为指导肺癌临床分期及判断预后的独立预测指标。     

小细胞肺癌患者血清趋化因子的表达及对术后复发或转移的影响

目的检测小细胞肺癌(SCLC)患者血清巨噬细胞炎症蛋白3α(MIP-3α)水平,并分析在术后早期复发与转移中的意义,探讨不同因素对患者术后复发或转移的影响。方法选择本院2013年9月—2015年2月收治的SCLC患者100例,为观察组,选择同期体检健康人员20例作为对照组。观察组患者根据术后是否转移或复发,未发生转移或复发56例,为观察组1,转移或复发44例,为观察组2。检测对照组及观察组患者术前及术后30d,90d,180d血清MIP-3α水平。记录术中指标,分析相关因素对患者复发与转移的影响。结果观察组术前血清MIP-3α为(98.65±9.30)pg/m L,高于对照组(23.74±6.85)pg/m L,差异具有统计学意义(P0.05)。观察组术后血清MIP-3α均低于术前,差异均具有统计学意义(P0.05)。观察组2术后180d血清MIP-3α为(69.47±7.82)pg/m L,高于观察组1(61.08±8.14)pg/m L,差异均具有统计学意义(P0.05)。观察组2术后MIP-3α高水平发生率为65.91%(29/44),高于观察组1患者术后21.43%(12/56),差异具有统计学意义(P0.05)。结论 MIP-3α在SCLC患者血清中的浓度显著增加,术后呈现下降趋势,与术后复发或转移呈正相关,可作为患者术后早期复发和转移检测指标。     

血浆白介素-1β水平对中重度急性呼吸窘迫综合征预后作用

目的探讨白介素-1β(IL-1β)在急性呼吸窘迫综合征(acute respiratory distress syndrome,ARDS)患者预后的作用。方法采用前瞻性病例对照研究的方法,收集和随访患者。收集ARDS组(分为中度组和重度度)和健康对照组的人口学特征和血清IL-1β水平。ARDS患者组第1、3和28天的APACHEⅡ、白细胞计数、降钙素原、超敏C反应蛋白、血清乳酸和白蛋白等血清学资料。结果 ARDS第1天生存组和死亡组在年龄、性别、APACHEⅡ评分、白细胞计数、降钙素原、超敏C反应蛋白、白蛋白和乳酸的比较,差别均无统计学意义(P0.05),死亡组PH低于生存组((P0.05);ARDS确诊第1天患者的IL-1β水平为145.1±29.8 pg/m L高于健康对照组14.3±12.4 pg/m L,差异具有统计学意义(t=22.196,P=0.000);ARDS患者第3天中度组血清IL-1β水平为114.2±48.7pg/m L低于重度组的159.8±35.6pg/m L,差异具有统计学意义(t=-2.7795,P=0.0096)。ARDS患者第3天生存组血清IL-1β为109.8±43.9pg/m L,低于死亡组的150.5±50.3pg/m L,差异有统计学意义(t=-2.3614,P=0.0256);ARDS第3天IL-1β的AUC为0.795(95%CI0.587-0.962,P=0.021),差异具有统计学意义,28天死亡预测值为78.45 pg/m L,灵敏度为87.5%,特异度为62.8%。结论中重度ARDS患者早期动态观察IL-1β水平有助于评估疾病的严重程度和预测预后。     

肺癌患者血清转化生长因子β1水平检测及临床意义

目的探讨血清转化生长因子β1(TGF-β1)水平与非小细胞肺癌之间的关系。方法新确诊非小细胞肺癌患者43例,全部病例均经病理学证实。正常自愿者30例作为对照。采集患者和健康自愿者外周静脉血2m l,应用EL ISA法测定血清TGF-β1水平。结果肺癌患者和健康对照组血清TGF-β1浓度分别为38.01±15.15pg/m l和20.68±10.63pg/m l,明显高于正常对照组(P<0.001)。各期肺癌患者血清TGF-β1浓度差异无显著性(P>0.05)。有远处转移患者和无远处转移患者的血清TGF-β1浓度分别为48.75±16.88pg/m l和33.70±7.49pg/m l,P<0.001。结论非小细胞肺癌患者的血清TGF-β1水平显著高于健康对照组,有远处转移者血清TGF-β1水平显著高于无远处转移者。血清TGF-β1浓度可能为肺癌的血清学标志物。     

肺癌患者胰岛素样生长因子1和胰岛素样生长因子结合蛋白3的表达及其临床意义

目的 分析肺癌患者血清和支气管肺泡灌洗液（BALF）中胰岛素样生长因子1（IGF-1）、胰岛素样生长因子结合蛋白3（IGFBP-3）的表达,探讨其在肺癌诊断和预后中的临床意义.方法 运用免疫放射法检测80例非小细胞肺癌患者和14名健康者（对照组）外周血血清与BALF中IGF-1、IGFBP-3的水平.结果 肺癌组血清和BALF中IGF-1表达显著高于对照组（P＜0.01）,IGFBP-3的表达显著低于对照组（P＜0.05）,同时IGF-1/IGFBP-3升高（P＜0.01）.IGF-1、IGF-1/IGFBP-3在有淋巴结转移、远处转移和TNMⅢ～Ⅳ的肺癌患者血清、BALF中明显高于无转移者和TNMⅠ～Ⅱ期者（P＜0.05）,而IGFBP3下降明显高于无转移者及TNMⅠ～Ⅱ期者（P＜0.05）.肺癌组血清IGF-1、IGFBP-3浓度与BALF中的浓度呈正相关（P ＜0.01）;患者血清BALF中IGF-1与IGFBP-3浓度呈负相关（P＜0.05）.结论 非小细胞肺癌患者血清和支气管肺泡灌洗液中IGF-1、IGFBP-3的表达对肺癌的诊断、判断预后有重要临床意义.     

NSCLC患者血清AGR2水平在预后判断中的应用价值

目的：观察非小细胞肺癌(non-small cell lung cancer,NSCLC)患者化疗前后血清前梯度蛋白2(anterior gradient-2,AGR2)水平的变化及其对预后的影响。方法选取60例 NSCLC患者,给予吉西他滨联合顺铂化疗方案,并以20名健康体检者作为正常对照组,采用酶联免疫吸附测定法分别检测肺癌组化疗前后及正常对照组血清 AGR2含量,分析 AGR2水平与临床病理特征及预后的关系。结果肺癌组化疗前血清AGR2水平高于正常对照组[(14.41±4.12)μg/L vs (3.65±1.38)μg/L, t=7.657,P=0.000]。肺癌组化疗后血清 AGR2含量为(7.58±2.52)μg/L,显著低于化疗前水平(t=4.052,P=0.003)。NSCLC患者化疗前后血清 AGR2水平与肿瘤直径、临床分期、有无淋巴结转移有密切关系(P <0.05或P <0.01);COX 比例风险回归模型分析显示,化疗前血清 AGR2水平、淋巴结转移状态是影响患者生存时间的独立危险因素。结论血清 AGR2水平在评估 NSCLC 患者的化疗疗效及预后方面有着潜在的临床价值。     

血清VEGF、Ang-2对非小细胞肺癌诊断特异性及预后判断准确性作用分析

目的探讨血清中血管内皮生长因子(VEGF)和血管生成素-2(Ang-2)对非小细胞肺癌(NSCLC)诊断特异性及预后判断的作用。方法选取2011年1月至2014年1月在我院治疗的NSCLC患者178例(病例组),同时选取100例健康者作为对照组,检测血清VEGF和Ang-2含量,分析其与临床病理、预后的关系。结果病例组VEGF和Ang-2分别为(553.21±78.43)pg/mL和(390.12±90.70)pg/mL,明显高于对照组(P0.05);NSCLC患者VEGF和Ang-2与患者年龄、性别及病理类型无关(P0.05);伴淋巴结转移患者VEGF和Ang-2明显高于无淋巴结转移患者(P0.05);临床分期为Ⅲ-Ⅳ期患者VEGF和Ang-2明显高于Ⅰ-Ⅱ期患者(P0.05);VEGF高水平患者生存时间为(18.97±0.95)月,明显低于VEGF低水平患者的(23.80±0.82)月(P0.05);Ang-2高水平患者生存时间为(19.42±0.91)月,明显低于Ang-2低水平患者的(23.71±0.81)月(P0.05);VEGF曲线下面积为0.907,截断值为442.45pg/mL,灵敏度为91.60%,特异度为89.00%;Ang-2曲线下面积为0.802,截断值为312.43pg/mL,灵敏度为82.60%,特异度为85.00%。结论血清VEGF和Ang-2可作为NSCLC诊断以及预后判断的分子标志物,具有重要的临床应用价值。     

实时聚合酶链锁反应动态监测肺癌患者血清VEGF-R的表达及意义

目的探讨肺癌患者血清中血管表皮生长因子受体(VEGF-R)的含量及其临床意义。方法以甘油醛-3-磷酸脱氢酶(GAPDH)基因作为内参照基因,使用实时聚合酶链反应(RT-PCR)定量方法,动态监测VEGF-R在肺癌患者化疗前、中、后血清中的表达水平。结果 33例肺癌患者接受化疗前、化疗中、化疗后的VEGF-R水平存在差异性,两两比较有统计学差异(P0.05),VEGF-R表达水平随着化疗的进行逐渐降低(P0.05);肺癌患者血清中VEGF-R表达水平与年龄、性别、肿瘤分期均无明显关系(P0.05),而低分化程度患者血清VEGF-R表达水平明显高于高分化患者(P0.05),腺癌及其他病理其型患者明显高于鳞癌,有淋巴结转移患者高于无淋巴结转移患者(P0.05)。结论肺癌患者血清中VEGF-R表达水平在化疗前后存在差异性,并且其表达水平与肿瘤分化程度、病理类型和淋巴结转移有关,可作为肺癌患者化疗预后的指标。     

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。     

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.