Capillary electrophoretic analysis of ionic content in exhaled breath condensate and pH monitoring as a non-invasive method in gastroesophageal reflux disease diagnostics.

In this study, the ionic profile and pH of exhaled breath condensate (EBC) in a group of patients with acid and weakly acid reflux and no-reflux controls were compared. A portable sampler was used for non-invasive EBC collection from five exhalations. The ionic profile (anions, cations, organic acids) and pH of the collected EBC samples were measured by capillary electrophoresis with contactless conductivity detection and a pH microelectrode, respectively. Several ions were elevated in the patient groups. Sodium cation was elevated in weakly acid reflux (significance level p < 0.01) and acid reflux (p < 0.05) compared to no-reflux controls. Butyrate and propionate were elevated in both acid reflux and weakly acid reflux compared to no-reflux controls (butyrate: p < 0.01, propionate: p < 0.05). The median values of pH (after de-aeration with N2) were also significantly higher (p < 0.01) in groups with acid reflux and weakly acid reflux than in the control group with no reflux. The ionic analysis and simultaneous pH measurement offer a simple, cheap, fast, and non-invasive approach in gastroesophageal reflux disease diagnostics.

Evaluation of Important Analytical Parameters of the Peptest Immunoassay that Limit its Use in Diagnosing Gastroesophageal Reflux Disease.

GOAL: To evaluate the analytical parameters of a lateral flow (LF) pepsin immunoassay (Peptest) and assess its suitability in the diagnostics of gastroesophageal reflux disease (GERD). BACKGROUND: Peptest is a noninvasive assay to analyze pepsin in saliva, intended for use in GERD diagnostics. Although commercialized, fundamental studies on its performance are missing. The assay therefore requires basic analytical parameter evaluation to assess its suitability in clinical practice. STUDY: Assay reaction's time dependence, reader device repeatability, and individual LF devices and longitudinal pepsin concentration reproducibility in individual subjects was evaluated. Salivary pepsin was analyzed in 32 GERD patients with extraesophageal reflux symptoms and 13 healthy individuals. RESULTS: The assay's signal increase is not completed at the recommend readout time and continues to increase for another 25 minutes. The relative standard deviation of measurement was good when using the same LF device, ranging from 2.3% to 12.9%, but the reproducibility of 10 different individual LF devices was poor. The random error when analyzing the same saliva sample on 10 LF devices was as high as 36 ng/mL and this value is thus suggested as the positivity cut-off. Pepsin concentration in individual subjects during a 10-day period varied significantly. The sensitivity of the Peptest was 36.8% in the group with acid reflux and 23.1% in the group with weakly acid reflux. The specificity was 61.5%. CONCLUSIONS: The Peptest assay's sensitivity and specificity is low, the results are highly variable and it should not be used as a near-patient diagnostic method in primary care.

Monitoring the ionic content of exhaled breath condensate in various respiratory diseases by capillary electrophoresis with contactless conductivity detection.

The analysis of an ionic profile of exhaled breath condensate (EBC) by capillary electrophoresis with contactless conductivity detection and double opposite end injection, is demonstrated. A miniature sampler made from a 2 ml syringe and an aluminium cooling cylinder was used for the fast collection of EBC (under one minute). Analysis of the collected EBC was performed in a 60 mM 2-(N-morpholino)ethanesulfonic acid, 60 mM L-histidine background electrolyte with 30 µM cetyltrimethylammonium bromide and 2 mM 18-crown-6 at pH 6, and excellent repeatability of migration times (RSD <1.3% (n = 7)) and peak areas (RSD < 7% (n = 7)) of 14 ions (inorganic anions, cations and organic acids) was obtained. It is demonstrated that the analysis of EBC samples obtained from patients with various respiratory diseases (chronic obstructive pulmonary disease, asthma, pulmonary fibrosis, sarcoidosis, cystic fibrosis) is possible in less than five minutes and the ionic profile can be compared with the group of healthy individuals. The analysis of the ionic profile of EBC samples provides a set of data in which statistically significant differences among the groups of patients could be observed for several clinically relevant anions (nitrite, nitrate, acetate, lactate). The developed collection system and method provides a highly reproducible and fast way of collecting and analyzing EBC, with future applicability in point-of-care diagnostics.

Haplotype analysis of the interleukin-18 gene in Czech patients with allergic disorders.

The interleukin-18 (IL-18) gene on chromosome 11q22 has been suggested as a susceptibility factor for allergies. To test for a possible role of IL-18 polymorphisms in Czech population, case-control study including 958 subjects (633 allergic patients and 325 healthy controls) was performed. An allele-specific polymerase chain reaction was used to analyze variants at positions -607 C/A (rs1946518) and -137 G/C (rs187238) in the promoter region together with the polymerase chain reaction-restriction fragment length polymorphism method for the detection of polymorphism at position -140 C/G (previously -133 C/G, rs360721) in intron 1 of the IL-18 gene. The -1297 C/T (rs360719) polymorphism was genotyped by real-time-polymerase chain reaction, using a predevelopment TaqMan allele discrimination assay. There were no significant differences in distribution of alleles or genotypes in any of four single nucleotide polymorphisms in the IL-18 gene between controls and patients. However, subsequent analysis revealed a significant difference in haplotype frequencies between the allergic patients and healthy subjects (p < 0.01). Haplotype formed by -1297 C/-607 A/-137 C/-140 C alleles occurred significantly more frequently in patients than controls (0.0433 vs 0.0129; p < 0.0003; p(corr)< 0.01, OR = 3.37; 95% CI = 1.59-7.14). In contrast, there was no relationship among the IL-18 variants and total serum IgE level. Our results indicate that promoter polymorphisms in the IL-18 gene act in interaction and could play a role in allergic disorders.