二胺氧化酶在急性坏死性胰腺炎肠道损伤中的作用

目的探讨急性坏死性胰腺炎（ＡＮＰ）时血浆二胺氧化酶（ＤＡＯ）水平变化及其与肠道损伤的关系．方法通过向主胰管内注入牛磺胆酸钠和胰蛋白酶复制犬ＡＮＰ模型（ｎ＝８）;检测血清淀粉酶水平;测定血浆、肠组织ＤＡＯ活性;测量回肠粘膜绒毛形态学改变．结果ＡＮＰ发病后ｄ１（ｍｏｌ／ｓ,００２５±０００６ｖｓ００１１±０００２）,ｄ２（ｍｏｌ／ｓ,００１９±０００５ｖｓ００１２±０００３）血浆ＤＡＯ活性增加,ｄ４（ｍｏｌ／ｓ,０００６±０００１ｖｓ００１４±０００２）以后明显下降,肠组织ＤＡＯ活性亦显著下降;回肠粘膜绒毛萎缩、脱落,高度、宽度降低,面积减少;血清淀粉酶水平升高３～１０倍;肝、胰、脾、肺、肾及肠系膜淋巴结出现细菌移位．结论ＡＮＰ时血中ＤＡＯ活性变化可反映肠粘膜上皮损伤,细菌移位则是肠屏障损伤的结果     

匹维溴铵对小鼠功能性腹泻及便秘的治疗作用

目的评价匹维溴铵对实验性便秘及腹泻小鼠的治疗作用．方法昆明小鼠３８只，随机分为腹泻组（ｎ＝１４），便秘组（ｎ＝１４）及正常对照组（ｎ＝１０）．采用复方苯乙哌啶制作小鼠便秘模型，番泻叶制作小鼠腹泻模型．便秘组及腹泻组动物分别给予匹维溴铵２００ｍｇ／ｋｇ·ｄ，正常对照组给予等体积生理盐水灌胃．观察各组ｄ０、ｄ１、ｄ３、ｄ５小鼠干粪点数、不排便只数、腹泻指数变化．ｄ５处死小鼠，取小鼠结肠做病理切片，观察结肠粘膜改变．结果匹维溴铵治疗结束时，腹泻治疗组小鼠的腹泻指数与正常对照组相比无差异（０００ｖｓ０００，Ｐ＞００５），与腹泻对照组相比明显降低（０００ｖｓ０７９±０１２，Ｐ＜００１），便秘治疗组小鼠的干粪点数与正常对照组相比无差异（１６４２±５２９ｖｓ１６５０±１８７，Ｐ＞００５），与便秘对照组相比明显增加（１６４２±５２９ｖｓ４８３±４２６，Ｐ＜００１）．结论我们采用非特异性的小鼠腹泻及便秘模型进行的研究结果表明，匹维溴铵对小鼠非特异性腹泻及便秘有明显的治疗作用．     

维拉帕米对实验性急性胰腺炎的保护作用

目的探讨维拉帕米对实验性急性胰腺炎的保护作用．方法雄性Ｗｉｓｔａｒ大鼠２２只，随机分为假手术组（ｎ＝５）、急性胰腺炎组（ｎ＝７）和维拉帕米保护组（ｎ＝１０）．用２０％牛胆酸钠溶液０１ｍｌ／１００ｇ逆行注入大鼠胰管内诱导急性胰腺炎．保护组在实验前经颈静脉输注维拉帕米１０ｍｇ／ｋｇ·ｈ维持１２ｈ．在０，６及１２ｈ分别断尾取血１０ｍｌ，测定血清淀粉酶活性．同时，在光镜和电镜下观察各组胰组织的病理变化．结果急性胰腺炎组在６，１２ｈ的血清淀粉酶值分别为２７９６±４５３和２４７８±３７８（ＩＵ／Ｌ）；其组织水肿和炎症细胞渗出评分分别为３１４±０６９和３００±０５８．维拉帕米保护组在相应时间的血清淀粉酶值仅为２１１３±４１１和１５７９±３１９（ＩＵ／Ｌ）；其组织水肿和炎症细胞渗出评分分别为１００±０８２和０９０±０３２．两组比较，有显著统计学差异（Ｐ＜００５或００１）．同时，前者电镜下见线粒体肿胀，内质网囊池扩大，自噬泡增加，而后者各细胞器基本正常．结论维拉帕米对实验性急性胰腺炎具有保护作用．     

中药清胰汤及双歧杆菌合剂对急性坏死性胰腺炎肠道细菌移位影响的比较研究

目的观察中药清胰汤（ＣＭ）及双歧杆菌合剂（ＢＭ）对犬急性坏死性胰腺炎（ＡＮＰ）肠道细菌移位（ＢＴ）的影响．方法杂种犬３１只,分对照组（ｎ＝７）、ＡＮＰ组（ｎ＝８）、中药治疗组（ＣＭ,ｎ＝８）和双歧杆菌合剂治疗组（ＢＭ,ｎ＝８）．对照组犬仅行剖腹术;经主胰管注入５％牛磺胆酸钠（０５ｍＬ／ｋｇ）和胰蛋白酶（３０００ｕ／ｋｇ）复制ＡＮＰ模型,ＣＭ组和ＢＭ组犬术后每日分别经胃管灌服中药清胰汤及双歧杆菌合剂结果与ＡＮＰ组比较,ＣＭ及ＢＭ组肠粘膜损害明显减轻;肠粘膜菌群中大肠杆菌、类杆菌数量减少,双歧杆菌、乳杆菌数量显著增加（Ｐ＜００５）,肠道微生态趋于平衡;ＣＭ组脏器细菌移位率减少５０％,ＢＭ组减少３７５％,两组移位细菌数量减少１０～４０倍;两组血培养阳性率均由１００％降为３７５％;两组血中内毒素水平下降１～２倍,淀粉酶水平下降２～３倍,磷脂酶Ａ２活性亦显著下降,并均于ｄ７后接近正常;肠通透性下降．结论中药清胰汤及双歧杆菌合剂具有减轻ＡＮＰ后肠粘膜损害,调节肠道菌群微生态平衡、保护肠屏障功能,从而减少ＢＴ致肠源性感染的作用     

生长激素对实验性急性坏死性胰腺炎肠道细菌移居的影响

目的 探讨生长激素（ｇｒｏｗｔｈ ｈｏｒｍｏｎｅ,ＧＨ）对急性坏死性胰腺炎（ａｃｕｔｅ ｍｅｃｒｏｔｉｚｉｎｇｐａｎｃｒｅａｔｉｔｉｓ,ＡＮＰ）肠道细菌移居的 影响。方法 采用胆胰管内逆行注射５％牛碘胆酸钠溶液诱导大鼠ＡＮＰ模型。１３７只在鼠随机分成３组：假手术组（ｎ＝４１）、ＡＮＰ＋ＮＳ组（ｎ＝４８）和ＮＡＰ＋ＧＨ组（ｎ＝４８）。ＧＨ治疗组大鼠皮下注射０．７５Ｕ／ｋｇ体重基因重组ＧＨ。观察血清淀     

急性胰腺炎178例预后因素分析

目的分析急性胰腺炎（ＡＰ）的预后因素．方法ＡＰ患者１７８例，男７６例，女１０２例，年龄１７岁～８５岁，平均５３６岁±１６岁，其中水肿型１２０例，坏死型５８例．分别以Ｒａｎｓｏｎ标准和ＢａｎｋＷｉｓｅ标准作为判断轻症和重症的标准．ＣＴ和（或）Ｂ超对ＡＰ的诊断采用Ｂａｌｔｈａｚａｒ分级法．结果Ｒａｎｓｏｎ标准５项以下者（轻症）１４９例，死亡率为６０４％，６项以上者（重症）２９例，死亡率为６５５０％．ＢａｎｋＷｉｓｅ标准阴性者（轻症）１４４例，死亡率为４１７％．１项以上阳性者（重症）３４例，死亡率为６４７０％．预测轻症和重症的死亡率这两种标准间差异无显著性（Ｐ＞００５）．年龄、胰腺坏死程度、并发症等对ＡＰ预后有显著的影响（Ｐ＜００１）．ＣＴ和（或）Ｂ超诊断急性坏死型胰腺炎（ＡＮＰ）的敏感度为７０７％，特异度为１００％．结论Ｒａｎｓｏｎ标准应结合ＢａｎｋＷｉｓｅ标准，综合考虑胰腺坏死程度，并发症等对ＡＰ预后的影响．ＣＴ、Ｂ超等影象学诊断对于判断胰腺坏死程度有一定的参考价值．     

大肠癌P53蛋白PCNA和CEA的表达与淋巴结转移的关系

目的研究大肠癌Ｐ５３蛋白、增殖细胞核抗原（ＰＣＮＡ）和ＣＥＡ的表达与淋巴结转移的关系．方法应用链霉菌素生物素（ＳＰ）免疫组化法，观察４４例大肠癌Ｐ５３，ＰＣＮＡ的阳性率和ＣＥＡ的表达型式．结果大肠癌Ｐ５３阳性率为５２３％；大肠癌Ｐ５３阳性表达与性别、年龄及肿瘤的部位、分化程度和浸润深度无关（Ｐ＞００５）；大肠癌Ｐ５３阳性者其淋巴结转移率较阴性者高（１４／２３，６０９％ｖｓ６／２１，２８６％，Ｐ＜００５）；Ｐ５３阳性表达及有淋巴结转移者其细胞增殖活性分别较Ｐ５３阴性表达及无淋巴结转移者高（５５９±１７ｖｓ３７９±１４，Ｐ＜００５；５６２±１５ｖｓ３９６±１７，Ｐ＜００５）；Ｐ５３阳性表达及有淋巴结转移者其ＣＥＡ表型均以胞质型和间质型为主（２１／２３，９１３％ｖｓ１３／２１，６１９％，Ｐ＜００５；１９／２０，９５０％ｖｓ１５／２４，６２５％，Ｐ＜００５）．结论检测Ｐ５３和ＰＣＮＡ表达及ＣＥＡ表型对判断大肠癌的恶性程度，预测其淋巴结转移趋势和预后及指导临床治疗有重要价值．     

冬虫夏草多糖治疗慢性丙型肝炎患者的临床研究

目的研究冬虫夏草多糖（ＣＰ）治疗慢性丙型肝炎的疗效．方法慢性丙型肝炎患者２１例，口服ＣＰ１５ｍＬ，３次／ｄ，连服３ｍｏ，治疗前后检测肝功能、血清肝纤维化标志物外周血Ｔ细胞亚群及ＮＫ活性的变化．结果慢性丙型肝炎患者经ＣＰ治疗后，血清ＡＬＴ（Ｕ／Ｌ，６１±３５ｖｓ３５±１５）及ｒＧＴ（Ｕ／Ｌ，１６９±８５ｖｓ１１８±５２）较治疗前显著降低（Ｐ＜００５）．血清ＨＡ（μｇ／Ｌ，２９３±１０９ｖｓ２１４±９６）、ＰⅢＰ（μｇ／Ｌ，１４３±４８ｖｓ１１４±４２）及ＣⅣ（μｇ／Ｌ，２４５±９８ｖｓ１８８±８７）均较治疗前显著下降（Ｐ＜００１，＜００５及＜００５）；ＣＤ４（３６４％±６６％ｖｓ４１０％±５６％）、ＣＤ４／ＣＤ８（１１４±０４０ｖｓ１４３±０２２）、ＮＫ（１６７％±４６％ｖｓ１９７％±４２％）均较治疗前显著增加（Ｐ＜００１），而ＣＤ８（３２６％±４７％ｖｓ２８９％±３７％）则明显降低（Ｐ＜００５）；血清胆红素略减、清蛋白略增但差异均无显著性．结论冬虫夏草多糖可以增强慢性丙型肝炎患者细胞免疫功能，改善肝功能，并具有一定的抗纤维化作用     

急性白血病患者血浆可溶性Fas受体的水平及其意义

目的：了解急性白血病患者血浆可溶性Ｆａｓ（ｓＦａｓ）受体水平及其意义。方法：用酶联免疫吸附试验法（ＥＬＩＳＡ）检测３０例急性白血病患者的血浆ｓＦａｓ含量,并与正常对照组比较。结果：难治复发患者ｓＦａｓ含量（ＡＮＬＬ９．６９±３．５１μｇ／Ｌ; ｎ＝８,ＡＬＬ７．１４±２．１８μｇ／Ｌ; ｎ＝７）显著高于（ Ｐ＜０．０１）正常对照（３．４９±２．３６μｇ／Ｌ）和ＣＲ组（ＡＮＬＬ４．２３±１． ９８μｇ／Ｌ;ｎ＝８,ＡＬＬ ３．７２±０．７２μｇ／Ｌ; ｎ＝７）。 ＡＮＬＬ与 ＡＬＬ患者 ｓＦａｓ水平比较,差异无显著性（ Ｐ ＞０． ０５）。结论：初步提示血浆ｓＦａｓ水平升高与急性白血病预后不良有关。     

经乳头内镜胰腺假性囊肿引流术

文章报告了３０例接受经乳头内镜胰腺假性囊肿引流术（ｅｎｄｕｓｃｏｐｉｃｔｒａｎｓｐａｐｉｌｌａｒｙｃｙｓｔｄｒａｉｎａｇｅ，ＥＴＣＤ）治疗的胰腺假性囊肿病人。２例病因为胆源性急性胰腺炎，２８例为慢性胰腺炎引起，平均主胰管最大直径４．２ｍｍ（３～１２ｍｍ），１１例存在胰管狭窄。本方法为通过主或副乳头置入假体管以引流与胰管系统相通的胰腺假性囊肿。施行诊断性ＥＲＣＰ后，进行短距（５ｍｍ）胰管括约肌切开术，可能的话事先行胆管括约肌切开术，扩张胰管狭窄后，置入胰管支架管，将导丝插入胰管并尽可能接近胰腺假性…     

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.