"杓型"与"非杓型"高血压患者的静息-活动和睡眠-觉醒昼夜节律

目的研究不同血压节律的高血压患者的静息-活动、睡眠-觉醒昼夜节律情况.方法对42例高血压患者和21例健康志愿者进行研究,所有受试者同时佩戴动态血压监测仪和静息活动监测仪进行动态血压和静息活动监测,动态血压监测24 h,而静息活动监测48 h.结果本次研究发现,非杓型高血压患者夜间活动水平(L5)显著增声(P＜0.05),睡眠效益(SE)显著下降(P＜0.05),夜间觉醒点数(WB)显著增多(P＜0.05),睡眠觉醒蒋碎指数(FI)显著增高(P＜0.05).结论与杓型高血压患者相比,非杓型高血压患者的静息-活动、睡眠-觉醒昼夜节律发生了变化,即夜间活动增多,睡眠效益下降,夜间觉醒点数和睡眠节律破碎性增加,活动与睡眠可能是影响血压昼夜节律的两个重要因素.     

吸烟和生物燃料所致慢性阻塞性肺疾病患者临床特征差异研究

目的 观察吸烟和生物燃料所致慢性阻塞性肺疾病(COPD)患者临床特征的差异。方法 回顾性分析2011年3月至2014年3月在广州呼吸疾病研究所206例由吸烟和81例生物燃料导致的慢阻肺患者的临床资料,分别比较了两组患者的一般情况、临床症状、呼吸困难评分和合并症等方面的差异;肺功能和分级及急性加重的差异。结果 (1)一般情况的差异：吸烟所致慢阻肺患者中男性和女性的比例分别为83.5%和16.5%,生物燃料所致慢阻肺的患者中男性和女性的比例分别为14.8%和85.2%(χ2=27.2,P<0.05)。吸烟所致慢阻肺患者多见于男性,而生物燃料所致慢阻肺患者多见于女性;性别矫正后,生物燃料所致的女性COPD患者的体重指数(BMI)低于吸烟所致的女性COPD患者的BMI。其他指标如年龄两组差异无统计学意义。(2)临床症状差异：生物燃料和吸烟所致慢阻肺患者的呼吸困难指数mMRC差异无统计学意义;生物燃料所致慢阻肺患者出现喘息症状多于吸烟所致慢阻肺的患者,分别为38.3%和11.1%(χ2=17.9,P<0.05)。生物燃料所致慢阻肺患者合并过敏性疾病(如过敏性鼻炎、支气管哮喘)比例高于吸烟所致慢阻肺的患者,分别为43.2%和18%(χ2=16.1,P<0.05);而吸烟所致慢阻肺患者合并肺癌比例高于生物燃料所致慢阻肺的患者,分别为7.77%和3.7%(χ2=9.7,P<0.05)。(3)肺功能分级的差异：慢阻肺分级上,性别校正后生物燃料所致慢阻肺患者分级更多见于B级或D级,症状多。(4)急性加重的差异：生物燃料所致和吸烟所致的慢阻肺患者1年内急性加重次数无显著差异。结论 吸烟和生物燃料所致的慢阻肺在临床特征上有很多差异：生物燃料所致慢阻肺患者多见于女性,BMI低,临床症状较多,合并症以过敏性鼻炎和支气管哮喘较多,慢阻肺分级多见于B级或D级。吸烟所致慢阻肺患者多见于男性,合并症以肺癌较多。     

高龄老年高血压患者血压昼夜节律及其影响因素分析

目的探讨高龄老年高血压患者血压昼夜节律的变化特点及其影响因素。方法回顾性分析2015年1月至2016年12月在我院住院治疗、年龄≥80岁的95例高龄老年高血压患者的临床资料,根据24小时动态血压(ABPM)监测结果将患者分为杓型血压组(23例)和非杓型血压组(72例),比较两组患者的ABPM及血压变异性、靶器官损害情况;对影响高龄高血压患者血压昼夜节律的因素进行多因素Logistic回归分析。结果在95例高龄老年高血压患者中,非杓型血压患者72例占75.8%,杓型血压患者23例占24.2%。非杓型血压组患者的夜间平均收缩压、夜间平均舒张压显著高于杓型血压组患者,24小时收缩压变异系数(24h-SBP BPV)、24小时舒张压变异系数(24h-SBP BPV)小于杓型血压组患者,吸烟比例高于杓型血压组患者,差异均有统计学意义(P0.05)。非杓型血压组患者合并脑血管病、高血压性肾病、糖尿病的比例显著高于杓型血压组患者,服用ACEI、ARB类药物的比例显著低于杓型血压组患者,差异有统计学意义(P0.05)。多因素logistic回归分析结果显示,吸烟、糖尿病是影响高龄老年高血压患者血压昼夜节律、使其表现为非杓型血压的危险因素,而服用ARB类药物则是维持杓型血压的保护因素。结论高龄老年高血压患者血压以非杓型血压为主,夜间血压水平较高,变异系数下降,靶器官损害比较明显;吸烟和糖尿病是高龄老年高血压患者非杓型血压形成的危险因素,服用ARB类药物则是维持杓型血压的保护因素。     

“杓型”与“非杓型”高血压患者的静息-活动和睡眠-觉醒昼夜节律

目的 研究不同血压节律的高血压患者的静息-活动、睡眠-觉醒昼夜节律情况。方法 对42例高血压患者和21例健康志愿者进行研究，所有受试者同时佩戴动态血压监测仪和静息活动监测仪进行动态血压和静息活动监测，动态血压监测24h，而静息活动监测48h。结果 本次研究发现，非杓型高血压患者夜间活动水平（L5）显著增高（P〈0．05），睡眠效益（SE）显著下降（P〈0．05），夜间觉醒点数（WB）显著增多（P〈0．05），睡眠觉醒破碎指数（FI）显著增高（P〈0．05）。结论 与杓型高血压患者相比，非杓型高血压患者的静息-活动、睡眠-觉醒昼夜节律发生了变化，即夜间活动增多，睡眠效益下降，夜间觉醒点数和睡眠节律破碎性增加，活动与睡眠可能是影响血压昼夜节律的两个重要因素。     

慢阻肺急性加重期抗生素相关性腹泻临床特征分析

目的探讨慢性阻塞性肺疾病急性加重期(慢阻肺急性加重期)抗生素相关性腹泻(ADD)临床特点及预防对策。方法选择620例慢阻肺急性加重期患者作为观研究对象,根据ADD诊断标准判断ADD的发生率,观察ADD患者抗生素应用情况,引起ADD的危险因素;发生ADD后的治疗及结果。结果620例慢阻肺急性加重期患者中发生ADD共30例(4.84%),ADD发生于应用抗生素的(6.11±3.23)天;25例ADD患者表现大便次数增加,大便不成形、呈糊样或水样便,5例ADD患者大便含脓血、粘液。ADD患者应用抗生素依次为:广谱青霉素类、三代头孢、喹诺酮类、碳青霉烯类等。发生ADD(A组)30例患者年龄平均(69.23±10.34)岁、禁食比例23.33%、发生呼吸衰竭33.33%、应用抗生素(2.11±0.23)种、抗生素应用(14.78±3.09)天、进行侵袭性操作15.00%高于无ADD组的平均年龄(60.54±11.08)岁、禁食2.37%、呼吸衰竭7.12%、应用抗生素(1.52±0.28)种、抗生素应用时间(11.43±2.88)天、进行侵袭性操作6.78%(P0.05),是引起ADD的相关因素(P0.05)。30例ADD治疗后症状得到缓解,经粪检显示恢复正常。结论慢阻肺急性加重期患者为ADD危险人群,对病情有一定影响,应实施针对性措施减少ADD的发生。     

高龄老年高血压患者血压昼夜节律与时辰的关系

目的 探讨高龄老年高血压患者血压昼夜节律特点与时辰的相关性,分析其可能机制,以指导临床中西医治疗。方法 选取2019年1月至2022年6月浙江中医药大学附属第二医院年龄≥80岁住院高血压患者244例,予持续服用降压药等自然状态下,搜集24 h动态血压监测数据,观察分析血压昼夜节律特点,分析其夜间血压水平与时辰的关系。结果 高龄老年高血压患者血压节律以反勺型(112例,占45.9%)及非勺型(95例,占38.9%)为主。各分型组在夜间的血压平均值、最大值及各时辰平均血压值的差异有统计学意义,反勺型组最高。夜间平均收缩压及夜间时辰平均收缩压,反勺型组和非勺型组均达到夜间高血压诊断标准,且于卯时(05:00—07:00)达到清晨高血压诊断标准。夜间时辰血压变化曲线,除反勺型持续高水平状态,余总体以前半夜亥时(21:00—23:00)及清晨卯时增高为主。结论 高龄老年高血压患者血压昼夜节律以反勺型、非勺型为主,且有夜间高血压及清晨高血压表现,反勺型夜间血压水平最高,血压波动可能与时辰有关。     

慢性阻塞性肺疾病合并支气管扩张的CT Bhalla评分与临床的相关性研究

目的本次研究拟通过慢性阻塞性肺疾病(慢阻肺)合并支气管扩张患者CT的Bhalla评分与临床症状、肺功能、BODE等指标的相关性,寻找应用CT评价慢阻肺疾病合并支气管扩张的方法,并依此确立慢性阻塞性肺疾病合并支气管扩张的影像学分类及临床特点。结果根据CT影像表现分成两个分类:A型:单慢阻肺患者(72例),其中男性50例,女性22例,年龄46-88岁,平均69.56±9.09岁,B型:慢阻肺合并支气管扩张的患者(72例),其中男性55例,女性17例,年龄28-89岁,平均65.67±13.10岁。两组慢阻肺患者的临床特征、肺功能、Bhalla评分、BODE指数及急性加重等均存在差异。结论 1、慢阻肺合并支气管扩张的患者,有必要积极早期干预。2、CT Bhalla Score作为常规肺功能的补充,同时为评估慢阻肺患者的生活质量及预后,提供临床证据。     

85岁以上老年人24小时动态血压特征分析

目的分析≥85岁老人的24 h血压参数变化,为制定这一特殊人群的临床血压控制方案提供依据。方法对89例年龄≥85岁的老人进行动态血压检测,分析其24 h、日间、夜间的平均血压、最高和最低血压、平均脉压差和血压变异性。结果血压节律呈非杓型者77例(86.52%),呈杓型者12例(13.48%),其中女9例,男3例。89例患者24h、日间、夜间平均收缩压分别为(126.7±14.0)mmHg,(126.7±14.2)mmHg和(126.6±17.0)mmHg。24 h、日间、夜间平均舒张压分别为(69.8±9.5)mmHg,(70.2±9.8)mmHg和(68.0±11.2)mmHg。夜间收缩压下降0.1%,夜间舒张压下降3.1%。男性24 h平均收缩压、夜间平均收缩压、夜间平均舒张压、夜间最低收缩压和夜间最低舒张压均显著高于女性(P<0.05)。结论大多数≥85岁高龄老人血压昼夜节律消失,男性夜间血压显著高于女性。     

老年慢性阻塞性肺疾病频繁急性加重表型患者的临床特征北大核心CSCD

目的探讨老年慢性阻塞性肺疾病(慢阻肺)频繁急性加重表型患者的临床特征。方法回顾性分析,选取山西医科大学附属白求恩医院呼吸科2015年8月至2016年9月门诊随诊的93例稳定期老年慢阻肺患者,分为频繁急性加重表型组45例和非频繁急性加重表型组48例,并采集患者体质指数(BMI)、肺功能、吸烟指数(包年)、呼吸状况问卷及血肌酐水平,采用Logistic回归分析老年患者慢阻肺急性加重频率的影响因素。结果慢阻肺频繁急性加重表型患者BMI[19.59(18.08~23.50)kg/m2]低于非频繁急性加重表型[23.36(21.14~25.46)kg/m2],而mMRC量表评分[3.00(1.00~3.00)分]、CAT评分[15.00(8.50~17.50)分]、吸烟指数[60.00(30.00~80.00)包年]均高于非频繁急性加重表型[1.00(0.00~1.00)分、10.00(6.00~13.75)分、37.50(3.75~60.00)包年],差异具有统计学意义(Z=8.898、17.671、7.318、6.589,P=0.003、<0.001、0.007、0.010);慢阻肺频繁急性加重表型患者肾小球滤过率(GFR)[105.13(89.84~114.69)ml·min-1·1.73m-2]低于非频繁急性加重表型[121.74(93.89~142.02)ml·min-1·1.73m-2],差异有统计学意义(Z=6.071,P=0.014);慢阻肺频繁急性加重表型患者第1秒用力呼气容积占预计值百分比[40.10(31.40~56.00)%]低于非频繁急性加重表型[70.65(47.36~85.36)%],差异有统计学意义(Z=17.814,P<0.001)。Logistic回归结果显示,吸烟指数和GFR的OR值(95%CI)分别为1.025(1.006~1.044)和0.957(0.927~0.995)(P=0.009、0.025),即随着吸烟指数增加和GFR降低,慢阻肺频繁加重的风险增加。结论频繁急性加重表型与非频繁急性加重表型老年慢阻肺患者存在差异,频繁急性加重表型老年慢阻肺患者BMI较低、吸烟指数更高、临床症状多、肺功能差,容易发生早期肾脏损伤。     

老年慢性阻塞性肺疾病患者25(OH)D水平与肺功能及急性加重的相关性

目的 分析老年慢性阻塞性肺病(慢阻肺)住院患者25羟维生素D〔25(OH)D〕水平,探讨25(OH)D水平与肺功能指标及前1年中到重度急性加重次数的相关性.方法 选取年龄≥60岁的住院慢阻肺患者275例,根据性别分为男性组(180例)和女性组(95例),根据肺功能分级分为Ⅰ级(15例)、Ⅱ级(93例)、Ⅲ级(124例)...     

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.