老年2型糖尿病患者并发骨质疏松的临床分析

目的　探讨老年 2型糖尿病 (T2DM)患者骨质疏松的患病率。　方法　将老年T2DM患者 338例分为 6 0～ 6 9岁和 70～ 79岁组 ,应用DPX L骨密度仪测定患者腰椎、左侧股骨Ward’区骨密度 ,并与非老年 (5 0～ 5 9岁 )T2DM患者 199例及本地区健康老年人 (老年对照组 ) 5 31例进行骨密度及骨质疏松患病率的比较。　结果　 (1)女性老年T2DM组腰椎、Ward’s区的骨质疏松患病率均高于非老年T2DM组 ,但低于老年对照组 ,差异均有显著性 (P <0 0 5～ 0 0 0 1,70～ 79岁组腰椎除外 ) ;(2 )男性老年T2DM组腰椎骨质疏松的患病率与非老年T2DM组和老年对照组比较 ,差异无显著性 ;6 0～ 6 9岁组Ward’s区骨质疏松的患病率高于非老年T2DM组和同龄对照组 ,但 70～ 79岁组低于同龄对照组 ,差异均有显著性 (P <0 0 5～ 0 0 0 1) ;(3)老年T2DM组患病前的体质指数 (BMI)高于老年对照组 ,差异有显著性 (P <0 0 5～ 0 0 0 1)。　结论　老年T2DM患者骨质疏松的患病率因年龄、性别和部位的不同而表现为高于或等于非老年T2DM患者 ,低于或等于健康老年人。     

老年女性糖尿病患者与参考人群骨密度和骨质疏松患病率的比较

目的 探讨老年女性2型糖尿病患者是否容易并发骨密度减少和骨质疏松.方法 测量60～85岁老年女性2型糖尿病患者659例及老年女性健康体检者(对照组)666例的腰椎和髋部骨密度.结果 糖尿病组的腰椎骨密度显著高于对照组,分别为(0.757±0.122)g/cm2和(0.722±0.124)g/cm2(P＜0.001);骨质疏松患病率显著低于对照组,分别为33.1%和41.7%(P＜0.01);糖尿病组与对照组之间髋部各骨骼区域骨密度的差异均无统计学意义,但糖尿病组大转子的骨质疏松患病率显著高于对照组,分别为30.0%和24.3%(P＜0.05).以年龄为控制因子,糖尿病组和对照组的骨密度与绝经年龄无关,与绝经年限呈显著性偏相关[γ=-(0.116～0.265),P＜0.01],糖尿病组的病程与大转子和髋部总体的骨密度呈偏相关(γ=-0.134和-0.112,均为P＜0.01).结论 老年女性2型糖尿病患者的腰椎和髋部并非容易并发骨密度减少和骨质疏松.     

老年人腰椎和髋部骨密度测定T评分的一致性比较

目的 探讨老年人腰椎和髋部双能X线骨密度(DEXA)测定T评分的一致性及髋部骨密度(BMD)T评分在骨质疏松诊断中的意义。方法 在排除患有影响骨量的疾病及使用影响骨代谢药物者后，选择60-89岁老年人260(其中男123人，女137人)例作为为研究对象。受检者均接受问卷调查、胸腰段脊椎正侧位X线摄片，DEXA测定2-4腰椎(L2-4)椎体前后位和左髋部BMD(若左髋部发生过骨折或存有明显病变则改测右髋部)，并进行有关统计分析。结果 老年男性各年龄组L2-4 BMD T评分比髋部要高(P＜0．01或P＜0.05)；老年女性除在65—69岁、85—89岁年龄组腰椎BMD T评分比髋部要高(P＜0．01和P＜0.05)外，其余各组则差异无显著性。按照WHO标准，以髋部、腰椎和同时以髋部、腰椎BMD T评分为依据，在123例男性中，分别有19、6、5人被诊断为骨质疏松症；在137例女性中，则分别有35、17、14人被诊断为骨质疏松症；单以腰椎和同时以髋部、腰椎BMD T评分为依据所检出的骨质疏松症患者人数均少于单以髋部BMD T评分为依据者(P＜0．01)。结论 在老年人尤其是老年男性，其腰椎BMD T评分明显高于髋部，腰部BMD T评分在骨质疏松诊断中的意义更为重要。     

老年2型糖尿病患者并骨质疏松症临床分析

目的探讨老年2型糖尿病(T2DM)患者骨质疏松的患病率. 方法将老年T2DM患者338例分为60～69岁和70～79岁组,应用DPX-L骨密度仪测定患者腰椎、左侧股骨Ward'区骨密度,并与非老年(50～59岁)T2DM患者199例及本地区健康老年人(老年对照组)531例进行骨密度及骨质疏松患病率的比较. 结果 (1)女性老年T2DM组腰椎、Ward's区的骨质疏松患病率均高于非老年T2DM组,但低于老年对照组,差异均有显著性(P＜0.05～0.001, 70～79岁组腰椎除外);(2)男性老年T2DM组腰椎骨质疏松的患病率与非老年T2DM组和老年对照组比较,差异无显著性;60～69岁组Ward's区骨质疏松的患病率高于非老年T2DM组和同龄对照组,但70～79岁组低于同龄对照组,差异均有显著性(P＜0.05～0.001);(3)老年T2DM组患病前的体质指数(BMI)高于老年对照组,差异有显著性(P＜0.05～0.001). 结论老年T2DM患者骨质疏松的患病率因年龄、性别和部位的不同而表现为高于或等于非老年T2DM患者,低于或等于健康老年人.     

住院老年患者骨骼肌减少与骨密度的关系

目的探讨住院老年患者骨骼肌质量、骨骼肌指数与骨密度的关系,以及骨骼肌减少与骨质疏松的关系,为老年骨质疏松及脆性骨折患者的临床防治开拓新思路。方法连续选取重庆医科大学附属第一医院住院老年患者562例,测量身高、体重,计算体重指数(BMI),利用双能X线骨密度仪(DXA)测量不同部位骨密度(BMD)和T值、四肢骨骼肌质量(ASMM)、骨骼肌指数(RSMI)、脂肪百分比(fat%),用Pearson相关性分析法研究各变量之间的关系,用Logistic回归法研究骨骼肌减少、骨质疏松、脆性骨折的关系。结果不同性别老年患者RSMI均与BMD显著正相关(腰椎:男性r=0.203,P0.01,女性r=0.165,P0.01;髋部:男性r=0.253,P0.01,女性r=0.225,P0.01),且均与BMI呈高度正相关性(男性r=0.777,P0.01;女性r=0.791,P0.01),BMD亦与BMI呈显著正相关(腰椎:男性r=0.319,P0.01,女性r=0.236,P0.01;髋部:男性r=0.199,P0.01,女性r=0.211,P0.01)。老年女性骨质疏松和脆性骨折患病率明显高于男性,而老年男性骨骼肌减少的检出率则显著高于女性。老年男性骨骼肌减少与骨质疏松存在明显的相关性(β=0.774,P=0.002,OR=2.168),而老年女性二者无明显相关性。结论骨质疏松与骨骼肌减少存在性别差异,老年男性二者存在明显正相关,老年女性二者无显著相关;脆性骨折与骨质疏松及骨骼肌减少均密切相关,增加肌肉量对老年人群骨质疏松及骨折的防治有重要意义。     

桡骨远端骨皮质厚度与骨密度的相关性

目的探讨伤后腕关节正位X线影像测量桡骨远端骨皮质厚度的可行性、桡骨远端骨皮质厚度与髋部及腰椎骨密度之间的关系以及评估桡骨远端骨皮质厚度预测骨质疏松症的能力。方法对91例年龄≥50岁经X线确诊为桡骨远端骨折的患者行双能X线吸收检测法(dual energy X-ray absorptiometry,DXA)测定,根据T值分为两组:骨质疏松组55例,男性6例,女性49例,年龄52～83 (63. 5±8. 2)岁,体质量46～88 (57. 2±8. 1) kg,体质量指数(body mass index,BMI)(24. 3±3. 0) kg/m2;非骨质疏松组36例,男性2例,女性34例,年龄50～69 (57. 9±6. 1)岁,体质量42. 5～80. 0 (62. 5±8. 7) kg,BMI (25. 5±3. 3) kg/m2。通过医学影像信息系统(picture archiving and communication systems,PACS),在腕关节正位X线影像上,于距离尺骨远端关节面40、60 mm处测量桡骨远端双侧骨皮质厚度。结果骨质疏松组患者较非骨质疏松组年龄大、体质量轻,且桡骨远端骨皮质厚度较非骨质疏松组薄,骨皮质比率较非骨质疏松组低,差异有统计学意义(P0. 01);两组患者BMI差异无统计学意义(P0. 01)。桡骨远端骨皮质厚度与髋部骨密度正相关(r=0. 309,P=0. 000),与腰椎骨密度正相关(r=0. 445,P=0. 000)。一元线性回归分析表明:桡骨远端骨皮质厚度每增加1 mm,髋部骨密度值增加0. 071 g/cm2(R2=0. 230,P=0. 000),腰椎骨密度值增加0. 065 g/cm2(R2=0. 265,P=0. 000)。桡骨远端骨皮质厚度5. 2 mm为诊断骨质疏松最佳诊断临界点,其敏感度80. 4%、特异度69. 4%、阴性预测值69. 4%,曲线下面积为0. 749。结论桡骨远端骨皮质厚度与髋部及腰椎骨密度正相关,桡骨远端骨皮质变薄与骨质疏松相关,通过X线检查测量桡骨远端骨皮质厚度快速简便,可初步筛查骨量减少,并提示进一步行骨密度检查。     

血清睾酮水平与老年男性骨质疏松性髋部骨折的相关性

目的探究血清睾酮、雌二醇、碱性磷酸酶及骨密度与老年男性骨质疏松性髋部骨折的相关性。方法选取2015年9月1日至2018年11月30日4家三甲医院65～85岁男性髋部脆性骨折住院患者220例为试验组,选取同时期65～85岁无脆性骨折男性300例为对照组。检测两组受试者空腹血清睾酮、雌二醇、碱性磷酸酶水平,并进行腰椎、股骨颈、股骨大粗隆骨密度测定。结果试验组股骨大粗隆、股骨颈、腰椎骨密度低于对照组,差异有统计学意义[股骨大粗隆:(0. 834±1. 872) g/cm~2vs.(0. 892±0. 931) g/cm~2,P0. 01;股骨颈:(0. 677±2. 014) g/cm~2vs.(0. 728±3. 120) g/cm~2,P0. 01;腰椎:(0. 530±0. 034) g/cm~2vs.(0. 634±1. 592) g/cm~2,P0. 01]。试验组血清睾酮水平低于对照组,差异有统计学意义[7. 1 (4. 8,9. 1) nmol/L vs. 12. 3 (7. 9,16. 7) nmol/L,P0. 05];两组血清碱性磷酸酶、雌二醇水平差异无统计学意义(P0. 05)。Logistic回归分析校正三处骨密度值后发现,睾酮是脆性髋部骨折的危险因素(OR=2. 140,95%CI:1. 387～3. 302,P=0. 001)。结论血清睾酮水平降低可能是老年男性髋部骨折的危险因素之一,睾酮水平检测对老年男性骨质疏松性髋部骨折具有预测作用。     

老年髋部骨折患者的腰椎和股骨近端骨密度的比较

目的 通过比较老年髋部骨折患者的腰椎和股骨近端骨密度值,试图找出对于髋部骨折的更具有密切相关性的骨密度测定部位.方法 采用双能骨密度仪对102名65岁以上老年髋部骨折患者入院后2周内的脊柱和髋部两个部位骨密度测定,对组间和组内数据分别进行分散分析和t检验的统计学处理.结果髋部的骨密度无论在男性和女性组均比腰椎的骨密度要低,有非常显著差异(P<0.001).女性组的髋部及腰椎骨密度要比男性组为低,有非常显著差异(P<0.001).无论男性还是女性髋部骨折患者其腰椎的骨密度均无显著下降.结论 在老年髋部骨折患者测定股骨近端的骨密度值更能反映其实际骨质疏松情况.     

男性老年性骨质疏松

1999年中国五大行政区应用双能Ｘ线骨密度仪 (ＤＥＸＡ)联合抽样调查骨密度 ,以Ｔ值≤ - 2 .5ｓ诊断骨质疏松 ,发现 6 0岁以上中国人骨质疏松的患病率 ,男性 (调查 1891例 )明显低于女性 (调查2 0 5 3例 ) :腰椎2 4 男女分别为 11.0 %和 2 1.5 %,股骨颈分别为 10 .6 %和 2 7.3%,Ｗａｒｄｓ三角分别为15 .0 %和 2 8.6 %,而大粗隆部骨质疏松男性略高 ,男女性患病率分别为 14.4 %和 11.8%。男女骨质疏松患病率均随增龄而升高 ,以股骨颈骨质疏松为例 ,6 0～ 6 9岁男女分别为 4 .9%和 14.5 %,70～ 79岁分别为 11.3%和 2 8.6 %,80岁以上分别为18.…     

老年男性骨密度与钙调节激素测定

目的　探讨钙调节激素在老年男性骨质疏松症发病机制中的作用。　 方法 　 6 3例老年男性分为骨质疏松组与非骨质疏松组 ,测定骨密度 (BMD)、血清钙 (Ca)、磷 (P)、碱性磷酸酶 (AKP)、甲状旁腺激素 (PTH)、降钙素 (CT)、2 5羟维生素D[2 5 (OH) VitD] ,并与 37例青年男性对照。　 结果　老年男性BMD、CT、2 5 (OH) VitD均较对照组降低、PTH增高 (P <0 0 0 1)。骨质疏松组CT、2 5 (OH) VitD较非骨质疏松组降低、PTH增高 (P <0 0 1～ 0 0 0 1)。Ca、P、AKP无明显差异。　 结论 　增龄、钙调节激素异常是引致老年男性骨质疏松症的重要原因之一。     

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.