[Examination of gastric emptying rate by means of 13C-octanoic acid breath test. Methods of the test for adults and results of the investigation of healthy volunteers]. / Stanovení rychlosti evakuace zaludku pomoci dechového testu s 13C-oktanovou kyselinou. Metodika testu pro dospelé a výsledky vysetrení zdravých dobrovolníku.

BACKGROUND: 13C-octanoic acid breath test (13C-OABT) is a simple, safe and non-invasive technique for measuring gastric emptying. However, the method has not been standardized yet. Aim of the study was to work up, introduce and evaluate our own method of the 13C-OABT for adults. METHODS AND RESULTS: Ten healthy volunteers entered the study (5 men, 5 women, mean age 32 years, 50 % Helicobacter pylori positive). Standard test meals (with 100 mg 13C-sodium octanoate) were used three times within 3 weeks. The same solid meal (1,178 kJ) for Tests 1 and 2 contained scrambled egg (+ 3 g oil), white bread (40 g), butter (10 g) and distilled water (200 ml). Semi-solid meal (1,020 kJ) for Test 3 contained milk pudding (200 g) and distilled water (200 ml). Duplicate breath samples were obtained before and every 15 minutes after eating the test meal during 255 minutes. Altogether 1,080 breath samples were analysed twice (isotope ratio mass spectrometry, AP2003 Analytical Precision, UK). To assess the half-life of elimination (t1/2 E), we modelled the process of elimination with the incomplete gamma-function, which has a convenient form for the empiric plotting of breath test data. Mean t1/2E was 136+/-10 minutes (Test 1), 134+/-14 (Test 2) and 123+/-16 minutes (Test 3). Clinical reproducibility of 13C-OABT in particular persons was 98.2% (18 breath samples series), 90.8 % (15 samples) and 87.1% (9 breath samples series). There was a significant correlation between Test 1 and Test 2 results (r=0.887, p<0.0001). Mean difference of duplicate breath sample analysis was 1.460 % (in 540 pairs), mean baseline one-day analysis difference was 0.0982 (99.9274% accuracy). In healthy volunteers, normal range of t1/2E is 110-160 minutes for solids and 91-155 minutes for semisolid test meal. Using our own computed mean time of intermediate metabolism of 13C-octanoic acid (76.5+/-7.5 minutes), gastric emptying half-time is 33.5-83.5 minutes for solids and 14.5-78.5 minutes for semisolid test meal in healthy volunteers. CONCLUSIONS: The 13C-OABT is accurate non-invasive method for gastric emptying measurement.

High-performance liquid chromatographic determination of tramadol and its O-desmethylated metabolite in blood plasma. Application to a bioequivalence study in humans.

Simultaneous HPLC determination of the analgetic agent tramadol, its major pharmacodynamically active metabolite (O-desmethyltramadol) in human plasma is described. Simple methods for the preparation of the standard of the above-mentioned tramadol metabolite and N1,N1-dimethylsulfanilamide (used as the internal standard) are also presented. The analytical procedure involved a simple liquid-liquid extraction of the analytes from the plasma under the conditions described previously. HPLC analysis was performed on a 250x4 mm chromatographic column with LiChrospher 60 RP-selectB 5-microm (Merck) and consists of an analytical period where the mobile phase acetonitrile-0.01 M phosphate buffer, pH 2.8 (3:7, v/v) was used, and of a subsequent wash-out period where the plasmatic ballast compounds were eluted from the column using acetonitrile-ultra-high-quality water (8:2, v/v). The whole analysis, including the equilibration preceding the initial analytical conditions lasted 19 min. Fluorescence detection (lambda(ex) 202 nm/lambda(em) 296 nm for tramadol and its metabolite, lambda(ex) 264 nm/lambda(em) 344 nm for N1,N1-dimethylsulfanilamide) was used. The validated analytical method was applied to pharmacokinetic studies of tramadol in human volunteers.

Screening for organic acid disorders.

The detection of organic acidurias is a part of our screening programme for inherited metabolic diseases. Adapted procedure is differentiated and involves several steps: 1) thin-layer chromatography (TLC) in the case of an abnormal finding followed by 2) gas chromatography (GC). The next step of the investigation, using 3) gas chromatography mass-spectrometry (GS-MS) is reserved for more complicated and dubious analyses. In acutely sick patients and in the case of discrepancies between TLC results on the one hand, and clinical symptoms, supported by other laboratory findings on the other, the GC or GC-MS-analysis is performed immediately. Some examples of metabolic disorders, identified by this procedure, are presented.

[Diagnosis of Helicobacter pylori with the 13C-labeled urea breath test: study methodology]. / Diagnostika Helicobacter pylori pomocí dechového testu s ureou znacenou prirozeným izotopem uhlíku 13C: metodika vysetrení.

Helicobacter pylori is one of the most common causes of chronic bacterial infection in humans, and it is associated with many diseases of the upper gastrointestinal tract. The 13C urea breath test (13C-UBT) is a simple, non-invasive and global test for Helicobacter pylori detection. The test reflects the hydrolysis of 13C-labelled urea by Helicobacter pylori urease. The 13C-UBT is the gold standard test for Helicobacter pylori infection. Since the original description (in 1987) several modifications of 13C-UBT have been published to simplify and optimise the test. However, neither Standardised European Protocol nor Standard US Protocol were accepted. This paper gives the methodology of the 13C-UBT based on eur own study and on the review of the literature.

[Possibilities in the diagnosis of Helicobacter pylori]. / Soucasné moznosti diagnostiky Helicobacter pylori.

The authors present an overview of current possibilities of the diagnostics of Helicobacter pylori (HP) focused on non-invasive methods. The overview is based on author's own experience and studying of applicable literature. Non-invasive methods (endoscopy is not needed) include serology (blood tests) and breath tests. Both methods are compared one with the other (and with invasive methods as well) not only from the point of view of sensitivity and specificity, but especially from the point of view of their practical use and correct indication of their use. 13C urea breath tests are non-invasive global tests with 100% reproducibility, high sensitivity and specificity. It is possible to pursue them everywhere and send them by post for processing. The analysis time for one breath sample is within 60 seconds. Breath tests are the gold standard of diagnostics of HP and if only one test is used, they are the best way of verifying the success of eradication therapy, of examination of children and pregnant women and of implementing the population studies.

Comparison of different protocols for 13C-urea breath test for the diagnosis of Helicobacter pylori infection in healthy volunteers.

OBJECTIVE: The (13)C-urea breath test ((13)C-UBT) is the most accurate non-invasive method for diagnosis of Helicobacter pylori infection. However, several methodological issues have not been resolved yet. The aim of this study was to test different protocols of (13)C-UBT to find the optimal test drink and sampling interval. MATERIAL AND METHODS: (13)C-UBT was performed at 3-day intervals in 27 healthy volunteers using citric acid (test A), orange juice (B) and still water (C) as test drinks. Breath samples were collected from time 5 to 60 min. A total number of 2106 breath samples were analysed by isotope ratio mass spectrometry (cut-off value 3.5). RESULTS: Differences in delta values were greater than would be expected by chance (A versus B and A versus C at times 20, 25, 30, 35 and 40 min, p<0.05, Dunnett's method). There were no grey zone- or false-negative results among H. pylori-positive persons in test A at any time, but some were found in tests B and C. Optimal intervals for breath sampling are at times 20 or 25 min after (13)C-urea ingestion. CONCLUSIONS: Citric acid solution as a test drink and 20- or 25-min breath sampling intervals are optimal for the (13)C-UBT in healthy volunteers.