胰腺癌患者血清十二种肿瘤标记物的变化

目的探讨定量测定胰腺癌患者血清12种肿瘤标志物的临床意义.方法用蛋白芯片技术定量测定42例正常人、30例胰腺癌和16例胰腺炎患者血清12种肿瘤标志物的变化并对检测效果进行评价.结果 42例正常人血清CA19-9(KU/L)、NSE(μg/L)、CEA(μg/L)、CA242(KU/L)、Ferritin(μg/L)、β-HCG(μg/L)、AFP(μg/L)、f-PSA(μg/L)、PSA(μg/L)、CA125(KU/L)、HGH(μg/L)和CA153(KU/L)的含量分别为:12.42±10.62、2.24±1.41、1.78±1.04、5.73±5.67、91.17±78.47、0.64±0.33、2.96±3.89、0.13±0.11、0.62±1.38、5.46±9.53、1.63±2.37、9.83±9.40;30例胰腺癌患者血清12种肿瘤标志物含量依次为:279.47±402.0、9.50±11.30、8.57±21.95、98.23±89.33、301.98±216.63、1.49±2.28、5.50±7.69、0.27±0.62、1.62±3.23、167.16±252.49、3.38±8.38、43.22±99.34;16例胰腺炎患者其含量依次为:53.38±86.38、12.78±28.50、1.20±0.94、22.99±51.13、343.43±308.27、3.63±11.99、5.09±3.66、0.10±1.32、0.66±0.61、98.67±212.23、1.79±1.63、4.15±2.13.该蛋白芯片测定的敏感性为70.0%,特异性为89.7%,阳性预测值为77.8%,阴性预测值为88.1%. 结论采用蛋白芯片技术同时测定患者血清中多种肿瘤标志物,对普查肿瘤和临床疗效观察有较好应用价值.     

胰腺癌患者血清CA242定量测定及其意义

目的 探讨定量测定胰腺癌患者血清CA242的临床意义。方法 链亲和素-生物素双抗体夹心ELISA法定量测定83例健康人、28例胰腺癌、16例胰腺炎及68例其它肿瘤患者的血清CA242,并比较其在不同疾病间的差异。结果 血清CA242含量（U/ml）在83例正常人为7.34±5.09;28例胰腺癌为112.85±56.54;16例胰腺炎为8.91±4.58;68例其它肿瘤为23.10±39.89。该法测定胰腺癌患者血清CA242的灵敏度为85.7％,特异性为92.2％,阳性预示值为64.9％,阴性预示值为97.5％。结论血清CA242的定量测定是诊断胰腺癌的敏感而又特异的指标。     

多肿瘤标志物蛋白芯片诊断系统对胰腺癌的诊断价值

目的 探讨多肿瘤标志物蛋白芯片诊断系统对胰腺癌的诊断价值。方法 用多肿瘤标志物蛋白芯片诊断系统测定30例胰腺癌患者和30例健康人群血清12项肿瘤标志物(CA19-9、CA242、CEA、CA15-3 CA125、AFP、PSA、F-PSA、NSE、β-HCG、HGH、Fer)的含量。结果 30例胰腺癌患者中有27例上述血清肿瘤标志物阳性，阳性率为90％，健康人血清有3例肿瘤标志物阳性，阳性率为10％。从12项肿瘤标志物中筛选出有诊断意义的标志物是CA19-9、CA242和CEA。其中CA19-9敏感度和特异度最好，分别达80％和90％，联合检测可提高敏感度，达93．3％。结论 多肿瘤标志物蛋白芯片诊断系统对胰腺癌的诊断有一定的价值。     

肺血栓栓塞症患者凝血纤溶系统及肺血管内皮功能的变化

目的探讨肺血栓栓塞症(PTE)患者体内凝血纤溶系统及肺血管内皮功能的变化及其临床意义。方法采用酶联免疫吸附测定(ELISA)检测80例PTE患者(急性大面积PTE组20例、非大面积PTE组60例)、40名正常人(对照组)的血D-二聚体(D-D)、组织型纤溶酶原激活剂(t-PA)、纤溶酶原激活剂抑制物1(PAI-1)、血浆蛋白S(Ps)、血浆蛋白C(Pc)、凝血酶调节蛋白(TM)、抗心磷脂抗体(ACA)、同型半胱氨酸(Hcy)含量;采用发色底物法检测抗凝血酶Ⅲ活性(AT-Ⅲ)。结果急性大面积PTE组患者血D-D、t-PA、PAI-1、Ps、TM、含量分别为(1.46±0.62)mg/L、(11.4±6.9)μg/L、(88.2±27.5)μg/L、(22.40±9.40)mg/L、(6.8±1.1)μg/L,非大面积PTE组分别是(0.92±0.27)mg/L、(6.6±1.5)μg/L、(60.1±26.1)μg/L、(23.90±10.70)mg/L、(6.3±1.5)μg/L,均显著高于正常对照组的(0.38±0.10)mg/L、(4.7±1.4)μg/L、(35.7±9.2)μg/L、(16.10±6.20)mg/L、(3.0±0.5)μg/L(分别P<0.01、<0.05)。急性大面积PTE组患者血AT-Ⅲ含量为(86.0±11.8)%,非大面积PTE组为(90.1±9.0)%,显著低于正常对照组的(102.6±9.20)%(P分别<0.01、0.05)。两PET组患者ACA-IgG、IgM、IgA显著高于正常对照组,差异有统计学意义(P<0.05)。结论PTE患者存在凝血纤溶系统功能失衡和肺血管内皮损伤。     

血清巨噬细胞抑制因子-1在胰腺癌临床检测诊断中的应用价值

目的:探讨MIC-1作为新的肿瘤标志物在胰腺癌临床血清学诊断中的应用价值.方法:采用酶联免疫方法检测101例胰腺癌、10例胰腺良性病变患者及50例正常人血清中的MIC-1表达水平,并与肿瘤标记物CA199进行比较.结果:胰腺癌患者血清中MIC-1表达水平(1427±1056 ng/L)显著高于胰腺良性肿瘤(362±177 ng/L)和正常人血清水平(299±159 ng/L)(P<0.001).MIC-1检测胰腺癌的敏感性、特异性、阳性预测值、阴性预测值和AUC分别为81.2%、94%、96.5%、71.2%和0.92.分别高于CA199的相应对应值72.4%、89.6%、93.4%、61.4%和0.86.与CA199联合检测时,敏感性可提高至91.1%.结论:MIC-1有可能成为用于胰腺癌临床诊断的新肿瘤标记物.     

高敏C反应蛋白和心型脂肪酸结合蛋白对不稳定性心绞痛患者心脏意外事件的影响

目的探讨高敏 C 反应蛋白(hs-CRP)和心型脂肪酸结合蛋白(heart fatty acid bindingprotein,h-FABP)对不稳定性心绞痛(UAP)患者心脏意外事件的影响。方法将住院的心绞痛患者分成稳定性和不稳定性两组。其中,稳定性心绞痛(SAP)患者74例,男45例,女29例;UAP 患者56例,男29例,女27例。分别检测其血清 hs-CRP、h-FABP、心肌肌钙蛋白Ⅰ(cTn-I)和肌酸激酶-MB(CK-MB)的含量,并于2周内观察各组发生心脏意外事件的情况。并抽取同期门诊健康体检者50例作为对照组。结果 UAP 组的心脏意外事件发生率为26.8%,高于 SAP 组的10.53%(P<0.05);对照组无心脏意外事件发生。SAP 和 UAP 组患者血清 hs-CRP 的含量分别为(1.78±0.62)mg/L 和(7.64±2.18)mg/L,高于对照组的(0.59±0.27)mg/L(P<0.05,P<0.01);SAP 和 UAP 组血清h-FABP 的含量分别为(3.15±2.61)μg/L 和(16.46±5.28)μg/L,高于对照组的(1.83±0.75)μg/L(P<0.05,P<0.01);SAP 患者血清 cTn-I 的含量为(0.67±0.09)μg/L,与对照组(0.47±0.12)μg/L比较,差异无统计学意义(P>0.05)。UAP 组和 UAP 组中的Ⅲ级患者的血清 cTn-I 含量分别为(1.28±0.43)μg/L 和(2.14±1.49)μg/L,高于对照组的(0.47±0.12)μg/L(P<0.01)。而 UAP 组Ⅰ级和Ⅱ级患者其 cTn-1的含量为(0.53±0.13)μg/L 和(0.74±0.37)μg/L,与对照组比较差异无统计学意义;CK-MB 值各组间差异均无统计学意义。SAP 组中,发生心脏意外事件的患者其血清 hs-CRP 和 h-FABP 的含量分别为(6.32±2.06)μg/L 和(8.76±3.83)μg/L,高于对照组(P<0.01);UAP组中,发生心脏意外事件的患者其血清 hs-CRP、h-FABP 和 cTn-Ⅰ的含量分别为(9.82±3.15)μg/L、(22.21±8.87)μg/L和(2.68±0.48)μg/L,高于对照组(P<0.叭);另外,各组发生与未发生心脏意外事件的 CK-MB 值差异均无统计学意义。结论 hs-CRP、h-FABP 的联合检测较传统的心肌损伤检测指标 cTn-I 和 CK-MB 对 UAP 患者近期发生心脏意外事件的可能性具有更高的预测价值。     

老年晚发哮喘缓解期患者气道反应性和诱导痰炎性标志物的测定

目的检测缓解期老年晚发哮喘(LOA)患者气道反应性和诱导痰嗜酸细胞、嗜酸细胞阳离子蛋白(ECP)和白介素-5(IL-5)水平,探讨其临床意义。方法选择58例缓解期 LOA 患者,测定其气道反应性,并分别采用瑞氏染色、荧光免疫法和酶联免疫吸附试验检测诱导痰中嗜酸细胞数量、ECP 和 IL-5水平;选择25例急性发作期 LOA 患者和15例健康老年人作为对照。结果 58例缓解期 LOA 患者中,49例(84.5%)支气管激发试验阳性,9例(15.5%)阴性。缓解期 LOA 组诱导痰中嗜酸细胞数量[(9.3±3.1)%]、ECP[(144.2±68.1)μg/L]和 IL-5水平[(20.3±6.3)μg/L]显著低于急性发作期 LOA 组[(21.1±9.8)%、(399.3±172.5)μg/L 和(50.6±10.7)μg/L,P<0.01],但显著高于健康老年组[(1.3±0.7)%、(48.7±21.9)μg/L 和(10.3±3.2)μg/L,P<0.01]。气道反应性增高组患者诱导痰中嗜酸细胞数量[(12.7±3.6)%]、ECP[(171.3±69.8)μg/L]和 IL-5水平[(23.6±8.5)μg/L]显著高于气道反应性正常组[(3.1±1.3)%、(52.7±21.1)μg/L 和(13.7±4.1)μg/L,P<0.01]。结论缓解期 LOA 患者多数存在气道高反应性且气道炎症持续存在,测定患者气道反应性和诱导痰中炎性标志物有助于指导缓解期治疗。     

联合检测CEA、CA199和CA242在胰腺癌诊断中的应用价值

目的探讨用蛋白芯片法检测CEA、CA199和CA242在胰腺癌诊断中应用价值。方法用蛋白芯片法测定38例胰腺癌患者、65例非胰腺恶性肿瘤患者、37例良性疾病患者和20例健康人群血清CEA、CA199和CA242含量。结果CEA、CA199和CA242对胰腺癌有诊断价值，其中敏感性、特异性、阳性预测值、阴性预测值分别为60．3％、61．4％、36．3％和80．3％；81．3％、72．5％、52．6％和89．3％；79．0％、84．2％、64．5％和90．3％；联合检测可提高检测的特异性和阳性预测值。结论联合检测CEA、CA199和CA242有利于胰腺癌临床诊断。     

急性胰腺炎患者vW因子、P—选择素的变化及临床意义

目的 探讨急性胰腺炎(AP)患者血浆von Willebrand因子(vWF)、P-选择素的变化及临床意义。方法 采用双抗体夹心固相酶免疫法测定34例AP患者和30例健康献血者的血浆vWF、P-选择素水平,对其进行相关性分析。结果 AP患者发病24h的血浆vWF、P-选择素水平分别为(214.6±53.2)％和(81.8±17.7)μg/L,显著高于正常对照组的(107.5±29.6)％和(14.7±4.5)μg/L(P<0.01)。重症AP患者血浆vWF、P-选择素水平分别为(251.9±62.7)％和(95.9±21.7)μg/L,显著高于轻型AP患者的(195.8±35.7)％和(73.5±16.1)μg/L(P<0.01)。vWF、P-选择素预测重症AP的敏感性、特异性和准确性分别是91.7％、86.4％、88.2％和58.3％、81.8％、73.5％。结论 AP患者存在血管内皮损伤和血小板的过度活化。测定AP患者血浆vWF水平可早期预测病情的严重程度。     

老年人大肠癌诊断及随访中肿瘤标记物联合检测的价值

目的　评价血清学肿瘤标记物对老年人大肠癌诊断和随访的价值。　方法　采用微粒酶免疫法检测 16 3例老年人大肠癌患者和 2 9例老年大肠良性疾病患者血清糖类抗原CA19 9、CA5 0、CA2 4 2及癌胚抗原的表达 ,对 4 2例行根治术的大肠癌患者进行随访。　结果　大肠癌患者血清糖类抗原CA19 9、CA5 0、CA2 4 2及癌胚抗原水平分别为 (45 2± 2 1 3)、(2 9 7± 17 6 )、(43 2± 37 6 ) μg/L和 (18 7± 12 4 ) μg/L ,均高于大肠良性疾病患者〔分别为 (8 4± 11 5 )、(7 7± 5 2 )、(9 1± 6 3) μg/L和 (2 5± 1 8) μg/L〕 ,并随病程进展逐渐增高 ;4种肿瘤标记物对诊断的敏感性与大肠癌的分期有关 ;平行联合检测可使诊断的敏感性提高至 83 5 % ,系列联合检测可使特异性提高至 88 7% ;肿瘤根治术后 ,肿瘤标记物显著下降 ;术后肿瘤标记物未降至正常者复发或转移率为 73 3% ,而术后再升高者复发或转移率为 85 2 %。　结论　上述 4种肿瘤标记物对老年人大肠癌的诊断和随访及监测肿瘤复发和转移有一定的价值。肿瘤标记物的联合检测有助于大肠癌早期诊断 ,可增加诊断的敏感性和特异性     

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.