^13C呼气试验的方法学及在胃肠病临床的应用

^13C呼气试验因其具有安全和非侵害性等特点已被广泛应用于营养学、药物代谢和胃肠疾病诊断等研究。应用不同的标记物，除进行幽门螺杆菌感染检测外，还可在胃排空、胰腺外分泌功能、小肠细菌衍生、肝脏功能等检测中发挥重要作用。     

13C呼气试验:一种有益的消化系统疾病检测方法

稳定性核素13C呼气试验作为一种安全、简便、无创的检查.可以对脏器功能进行实时定量的评价,具有一定的敏感性和特异性,日益受到临床医生青睐.该文综述国内外13C呼气试验在消化系统疾病诊断领域的应用研究进展及其局限性,并对其发展作一展望.     

13C呼气试验:一种有益的消化系统疾病检测方法

稳定性核素13C呼气试验作为一种安全、简便、无创的检查.可以对脏器功能进行实时定量的评价,具有一定的敏感性和特异性,日益受到临床医生青睐.该文综述国内外13C呼气试验在消化系统疾病诊断领域的应用研究进展及其局限性,并对其发展作一展望.     

^13C呼气试验：一种有益的消化系统疾病检测方法

稳定性核素^13C呼气试验作为一种安全、简便、无创的检查，可以对脏器功能进行实时定量的评价，具有一定的敏感性和特异性，日益受到临床医生青睐。该文综述罔内外^13C呼气试验在消化系统疾病诊断领域的应用研究进展及其局限性，并对其发展作一展望。     

^13C—尿素呼气试验的方法学改进

＾１３Ｃ－尿素呼气试验是一种无创诊断幽门螺杆菌感染的好方法，但成本较高。我们探讨了＾１３Ｃ－尿素的给药剂量、收集呼气样品的时间以及呼气样品平均化处理等因素对降低检测成本的可能性。结果表明，对于一般成人给予１００ｍｇ＾１３Ｃ－尿素（儿童为６０ｍｇ），收集给药后５０分钟内的４次呼气样品，经样品混合平均化后可获得满意结果。     

^13C—尿素呼气试验技术改进及对幽门螺杆菌感染的诊断

＾１３Ｃ－尿素呼气试验（＾１３Ｃ－ＵＢＴ）诊断幽门螺杆菌（Ｈｐ）感染的重要方法之一。它具有无毒、无创伤、准确、快速等优点，但检测价格昂贵的问题一直阻碍着该方法的推广。近年来，研究人员在保证诊断灵敏度及特异性的前提下，对＾１３Ｃ－ＵＢＴ进行了多方面的改进，如新型价廉的检测仪器，低剂量＾１３Ｃ－尿素胶囊的应用，试验餐的改良及检测时间的缩短等，降低了检测成本，大大推动了＾１３Ｃ－ＵＢＴ的更广泛应用。     

^13C呼气试验的临床应用价值与发展前景

^14C呼气试验曾受到广泛关注，但鉴于^4C长达5730年的半衰期，对其在人体进行诊断性检测的应用仍存在争议。相对而言，稳定核素^13C呼气试验即使用于孕妇或儿童也十分安全。^13C-尿素呼气试验已被广泛应用于营养学、药物代谢学以及消化系统各种疾病的诊断研究中。近年来，随着各种不同的^13C标记底物相继研发及其呼气试验在临床中研究的深入，呼气试验的一些不足不断被弥补。     

73例~13C-尿素呼气试验检测幽门螺杆菌的观察

本文论述利用幽门螺杆菌的内源性尿素酶可特异性分解尿素的特性,以85mg稳定同位素~(13)C标记的尿素为示踪剂,观察了73例患者在口服~(13)C-尿素前后30min内呼气中~(13)CO_2浓度的变化,探讨了该方法在诊断胃幽门螺杆菌的价值.实验方法:空腹进150ml试餐后服85mg~(13)C-尿素,分别收集给药前及给药后30min的呼气.用气体同位素比值质谱仪测定~(13)CO_2的千分差值(δ‰).以Ib值表示Ib=Ib_(30)—Ib_0.部分病人组织粘膜用Giemsa染色和快速尿素酶观察.结果:73例Ib从0.1～2.85;其中阴性(Ib<0.6)42例,Ib值从0.01～O.48;阳性及强阳性31例(Ib～≥O.6),Ib从0.73～2.85.胃幽门螺杆菌感染率为42%,其中十二指脂球部溃疡病人75%阳性,胃溃疡病人57%阳性.21例病人同时用三种方法检测结果为组织粘膜Giemsa染色6例显示阳性,阳性率29%;组织粘膜快速尿素酶法显示9例阳性,阳性率43%;~(13)C-尿素呼吸试验显示17例阳性,阳性率81%,X~2值>2,有明显差异性.     

^14C—尿素呼气试验对胃幽门螺杆菌感染的诊断价值

目的建立１４Ｃ尿素呼气试验，评价其临床应用价值。方法胃镜下取胃窦粘膜作细胞培养及病理切片，染色阳性为幽门螺杆菌（Ｈｐ）感染的对比指标。对１３８４例临床怀疑为胃及十二指肠疾病的患者进行呼气试验，其中４４例行多时相动态呼气试验，以确定最佳集气时间。结果动态检测示３０分钟为１４Ｃ呼气量峰值，如将Ｈｐ阳性阈值定于呼气比值大于３５，则１４Ｃ呼气试验对Ｈｐ感染检出的灵敏度为９６７％，特异性为９６５％。１４Ｃ呼气试验在成人人群中的阳性率为５０４％，在儿童中为８１２％。结论１４Ｃ呼气试验在胃肠道Ｈｐ感染检测中具有良好的灵敏度及特异性，方法简便可靠，易于临床推广     

14C-尿素呼气试验诊断幽门螺杆菌感染的价值

 目的 探讨正常人群和慢性胃炎及消化性溃疡患者幽门螺杆菌(Hp)感染情况.方法 3 497例健康体检者和638例慢性胃炎和消化性溃疡患者行14C-尿素呼气试验(14C -Urea breath test,14C-UBT)Hp检测.计算机自动得出数据,2 min计数(dpm)＜100 dpm 为正常,即Hp阴性;＞101 dpm为异常,即Hp阳性.结果 健康体检3 497例,Hp阳性1 748例,阳性率50 %,发现胃癌1例(14C-UBT 1 200 dpm);慢性胃炎及消化性溃疡组638例,Hp阳性339例,阳性率53%.两组相比差异无统计学意义(P＞0.05).但是,健康体检组阳性者中＞601 dpm占41.2%(720/1748);慢性胃炎和消化性溃疡组阳性者中＞601dpm占38.3%(131/339).两组相比差异有统计学意义(P＜0.05).结论 在健康人群中存在有较高比例的Hp感染趋向,14C-UBT检测Hp的优点是简便、准确、安全、无创、经济、重复性好.     

Accuracy of a rapid 10-minute carbon-14 urea breath test for the diagnosis of Helicobacter pylori-associated peptic ulcer disease

Urease in the human gastric mucosa is a marker for infection with Helicobacter pylori (HP), an organism which is associated with peptic ulcer disease. To detect gastric urease, we examined 184 patients (144 males, 40 females; mean age: 49.8±15.6 years) with suspected peptic ulcer disease. Fasting patients were given orally 5 Ci of carbon-14 labelled urea. From each patient only one breath sample was collected in hyamine at 10 min. The amount of ¹⁴C collected at 10 min was expressed as follows: [(DPM/mmol CO₂ collected)/(DPM administered)] × 100 × body weight (kg). The presence of HP colonization was determined by examination of multiple endoscopic prepyloric antral biopsy specimens subjected to culture or a rapid urease test. For the purpose of this study, HP-positive patients were defined as those with characteristic bacteria as indicated by a positive result of either the culture or the rapid urease test; HP-negative patients were defined as those with negative findings on both the culture and the rapid urease test. Of the 184 cases, 99 (53.8%) were positive for HP infection, and 85 (46.2%), negative. The sensitivity and specificity of the rapid 10 min ¹⁴C-urea breath test for the diagnosis of HP-associated peptic ulcer disease were evaluated by a receiver operating characteristic (ROC) curve with a variable cut-off value from 1.5 to 4.5. When a cut-off value of 1.5 was selected, the sensitivity was 100% and the specificity, 83.5%; when a cut-off value of 4.5 was selected, the sensitivity was 54.5% and the specificity, 97.6%. Correspondence to: Chia-Hung Kao     

Biokinetics and radiation doses for carbon-14 urea in adults and children undergoing the Helicobacter pylori breath test

The long-term biokinetics and dosimetry of carbon-14 were studied in nine adults and eight children undergoing carbon-14 urea breath test for Helicobacter pylori (HP) infection. The elimination of ¹⁴C via exhaled air and urine was measured with the liquid scintillation counting technique and with accelerator mass spectrometry. After the subjects had been given 110 kBq ¹⁴C-urea (children: 55 kBq) orally, samples of exhaled air were taken up to 180 days after administration and samples of urine were collected up to 40 days. Sixteen of the subjects were found to be HP-negative. In these subjects a total of 91.1%±3.9% (mean of adults and children ± standard error of the mean) of the administered ¹⁴C activity was recovered. The majority of the administered activity, 88.3%±6.2% in adults and 87.7%±5.0% in children, was excreted via the urine within 72 h after administration. A smaller fraction was exhaled. In adults 4.6%±0.6% of the activity was exhaled within 20 days and in children 2.6%±0.3%. Uncertainties in the biokinetic results are mainly due to assumptions concerning endogenous CO₂ production and urinary excretion rate and are estimated to be less than 30%. The absorbed dose to various organs and the effective dose were calculated using the ICRP model for urea and CO₂. The urinary bladder received the highest absorbed dose: in adults, 0.15±0.01 mGy/MBq and in children of various ages (7–14 years), 0.14–0.36 mGy/MBq. The findings indicate that an investigation with ¹⁴C-urea gives an effective dose to adults of 2.1±0.1 μSv (for 110 kBq) and to children of 0.9–2.5 μSv (for 55 kBq). From a radiation protection point of view, there is thus no reason for restrictions on even repeated screening investigations with ¹⁴C-urea in whole families, including children. Received 27 October 1998 and in revised form 13 January 1999     

氨基比林呼气试验

ABT(氨基比林呼气试验)是研究最早、使用最多的肝功能呼气试验,主要应用于肝病诊断鉴别、肝硬化预后评估、手术干预危险性预测以及移植肝功能监测等方面,较之其他肝功能检查,它具有简单、安全、准确和非侵害性等特点。     

微量（14）~C－尿素胶囊呼吸试验检测幽门螺杆菌感染

为评价微量１４Ｃ－尿素胶囊呼吸试验（ＵＢＴ）检测幽门螺杆菌（Ｈｐ）感染的价值，４９例病人空腹口服３７ｋＢｑ１４Ｃ－尿素胶囊后收集呼出气，结果以每分钟计数表示。胃镜明确诊断后取活检，检测Ｈｐ，个别病人检测血清抗ＨｐＩｇＧ。Ｈｐ阴性者１０ｍｉｎ均数＋２标准差作为判定ＵＢＴ阴性和阳性的临界值（７０／ｍｉｎ）。其检测Ｈｐ的敏感性为１００％，特异性为９６．６％。     

13C标记试剂在消化系统疾病诊断中的研究进展

13C是稳定性核素，其标记的诊断试剂已逐渐应用于临床，尤其是13C标记的尿素呼气实验，其被广泛用于胃幽门螺旋杆菌感染的诊断。13C标记的其他化合物如氨基比林、美沙西丁、辛酸、混合甘油三酯等还可用于消化系统中其他疾病的诊断。由于13C标记的诊断试剂具有无创、安全、无辐射的特点，其适用于儿童、孕妇等患者，已受到越来越多学者的关注，该文对近几年13C在消化系统疾病诊断方面的研究进展作一综述。     

血浆中四种肿瘤标志物和13C-尿素呼气试验对胃癌诊断的对比研究

目的 探讨胃癌患者血浆中胃泌素、瘦素、糖类抗原125(CA125)、糖类抗原72-4(CA72-4)水平和13C-尿素呼气试验(13C-UBT)对胃癌诊断的对比研究.方法 采用放射免疫分析法、酶免疫吸附测定法测定126例胃癌患者(其中Ⅰ～Ⅱ期32例、Ⅲ期57例和Ⅳ期37例)和60名正常对照者血浆中胃泌素、瘦素、CAi25和CA72-4水平;用13C-UBT测定幽门螺旋杆菌(HP)感染的阳性率并进行比较性分析.结果 126例胃癌患者血浆中的胃泌素、CA125和CA72-4水平较60名正常对照者均明显升高(t分别为3.125、3.519、3.788,P均＜0.01),并随疾病的严重程度而增加;血浆瘦素水平较60名正常对照者明显降低(t=3.524,P＜0.01),并随疾病的严重程度不断减少.与正常对照组相比,4种肿瘤标志物中CA72-4水平变化最明显.126例胃癌患者HP感染的阳性率为84.9%,其中,Ⅰ～Ⅱ期、Ⅲ期和Ⅳ期胃癌患者HP感染的阳性率分别为46.9%、89.5%和89.2%;60名正常对照者HP感染的阳性率为15.0%.结论 通过对126例胃癌患者血浆中胃泌素、瘦素、CA125和CA72-4水平的分析表明,血浆中的CA72-4水平诊断胃癌为最佳,其次为瘦素、CA125及胃泌素.因胃癌与HP的关系密切,故尽早使用13C-UBT测定HP感染和治疗HP感染者甚为重要.     

消除质子泵抑制剂对14C-尿素呼气试验的影响

目的观察降低胃内pH值对消除因使用质子泵抑制剂(PPI)致14C-尿素呼气试验(UBT)假阴性的作用.方法 23例常规14C-UBT(UBT-1)阳性患者口服奥美拉唑40 mg/d,共14 d.于第13天行第2次常规14C-UBT(UBT-2).第14天行改良14C-UBT(UBT-3),即服用14C-尿素胶囊前30 min和服用胶囊时加饮200 mL 0.1 mol/L柠檬酸.比较3次UBT 14 CO2呼出量和假阴性率.结果奥美拉唑明显减少14CO2呼出量,UBT-1为(5.57±3.90) Bq/mmol, UBT-2为(1.98±1.42) Bq/mmol(t=5.867, P=0.000),UBT-3的14CO2呼出量增高至(4.93±3.77) Bq/mmol,明显高于UBT-2(t=-4.538, P=0.000).UBT-2有10例假阴性(43.5%),UBT-3有2例假阴性(8.7%,χ2=6.66, P<0.01).结论服用PPI的患者作14C-UBT时加饮柠檬酸可增加14CO2呼出量,降低假阴性率.