An analyzer aimed for single-breath detection of exhaled endogenous NO is described. It is based on lead-salt MBE tunable diode lasers (TDL) operating at 5.4 im spectral region. Specially designed high sensitive and fast acquisition system used in combination with the Herriott multipass gas cell allows 1 ppb concentration sensitivity to exhaled NO with about 0.5 5 temporal resolution. Careful selection of the used analytical spectral region ensures high NO detection selectivity in the condition of elevated water vapor and carbon dioxide content in exhaled air. Due to the TDL high spectral resolution the analyzer is also insensitive to the other numerous endogenous substances that could be present in exhaled air. The TDL NO analyzer was tested in measuring endogenous NO content in exhalation of patients suffering from different pulmonary diseases as well as of healthy control subjects. Some single-breath NO trace specific in asthma and COPD was observed allowing differentiation of these diseases with the exhalation NO test.Keywords: Biomedical diagnostics with tunable diode lasers, gas analysis of exhalation content, endogenous NO in exhaled air, NO excretion in asthma and COPD.
Middle infrared tunable diode lasers (TDL) were applied to studies of pulmonary excretion of endogenous carbon monoxide (CO). Variations of the CO content level in exhaled air of healthy nonsmokers were investigated for different environmental conditions with the applied laser technique. Correlation ofthe obtained data with atmospheric CO contamination and elevated oxygen content were studied as well as diurnal variations of the endogenous CO in exhalation was observed. Criteria for correct conditions ofthe endogenous CO detection in breath could be derived on this basis. Developed laser approach and methods were applied for the analysis ofthe excreted CO level in different diseases like bronchial asthma, cystic fibrosis, idiopathic pulmonary fibrosis, chronic obstructive pulmonary disease, anemia and hepatitis. Laser based close-to-real-time monitoring ofthe endogenous CO elimination with breath in the course of different dynamic tests was demonstrated to be informative in studies of blood oxygen transport and pH variations in tissues for different challenge tests in human physiology.Keywords: endogenous carbon monoxide, tunable diode lasers, gas analysis, blood gases, blood pH. INTRODUCTIONAt present, notions of very important role of endogenous carbon monoxides in human physiology are developing intensively16. This metabolic molecule can act together with nitrogen oxide (NO) as mediator taking part in signal transfer in the course of various control processes in organism. The last studies of carbon monoxide activity in organism indicate a specific role not only in metabolic regulation of hem-containing protein structures like hemoglobin, myoglobin and cytochromes, but also in more complicated biochemical processes like transmission of nerve impulses, maintaining micro vessel muscle tone, inducing chemoreceptor activity, control of some hypothalamus hormone secretion etc. . Besides, CO elimination with breath is sensitive to blood pH variations7 and to extent of blood saturation with oxygen and thus could characterize gas transport properties of blood, its acid-base balance and biochemistry.Generation of CO in organism is known to be caused mainly by catabolism of hem-containing structures such as cytochrome, myoglobin, catalase, peroxidase, that normally takes place in cells of liver, spleen and red marrow8. Endogenous CO excreted due to this process is then bound by hemoglobin of blood erythrocyte to be transported from these organs to lung and then is excreted with exhaled airY. Incidentally a part of the CO could be captured and SPIE Vol. 3829 • 0277-786X1991$1O.OO 77 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/20/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspxaccumulated for some time by muscle fiber myoglobin and cell cytochromes that have a higher affinity for Co than hemoglobin Normally endogenous CO concentration in exhale air is constant because the rate of the CO production at normal conditions is stable. At the same time it could be affected by several reaso...
An analyzer of 13C02/'2C02 ratio in exhaled air based on lead-salt tunable diode lasers is presented. High accuracy of the carbon isotope ratio detection in exhaled carbon dioxide was achieved with help ofvery simple optical schematics. It was based on the use of MBE laser diodes operating in pulse mode and on recording the resonance CO2 absorption at 4.2 inn. Special fast acquisition electronics and software were applied for spectral data collection and processing. Developed laser system was tested in a clinical trail aimed to assessment eradication efficiency in therapy of gastntis associated with Helicobacter pylon infection. Data on the '3C-urea breath test used for P.pylori detection and obtained with tunable diode lasers in the course of the trail was compared with the results of Mass-Spectroscopy analysis and histology observations. The analyzer can be used also for '3C02/'2C02 ratio detection in exhalation to perform gastroenterology breath tests based on using other compounds labeled with stable isotopes.Keywords: tunable diode laser spectroscopy, '3C02/'2C02 ratio analysis, breath test, noninvasive diagnostics in gastroenterology, assessment ofthe Helicobacterpylori infection and eradication.
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