Functional Lung Examination in Diagnostics of Asthma and Its Phenotypes

In this chapter, we review the diagnostic approach to asthma phenotypes in children using lung function testing. Various methods are reviewed and their advantages and disadvantages are discussed. Medical history and physical examination including lung auscultation is the first line examination, which may raise the suspicion on asthma. Besides the simple lung auscultation, more advanced approaches (computer analysis of breath sounds) are described. Spirometry and other classical lung function testing methods (body plethysmography, dilution techniques) are discussed with respect to their contribution to asthma diagnostics and phenotype classification. Afterward, impulse oscillometry and methods intended for patients with insufficient cooperation follows. We highlight their potential in diagnostics of early asthma stages. Measurement of exhaled nitric oxide is discussed and its potential for allergic asthma (eosinophilic inflammation) detection is assessed. In conclusion, various lung function testing methods may contribute to both setting the diagnosis of asthma itself and classification of asthma phenotypes. Their smart combination allows for more precise diagnostics and treatment of young patient with bronchial asthma

Indicator-based and indicator-free magnetic assays connected with disposable electrochemical nucleic acid sensor system

WOS: 000263634700028PubMed ID: 19174223An indicator-based and indicator-free magnetic assays connected with a disposable pencil graphite electrode (PGE) were successfully developed, and also compared for the electrochemical detection of DNA hybridization. The oxidation signals of echinomycin (ECHI) and electroactive DNA bases, guanine and adenine, respectively were monitored in the presence of DNA hybridization by using differential pulse voltammetry (DPV) technique. The biotinylated probe was immobilized onto the magnetic beads (magnetic particles, microspheres) and hybridization with its complementary target at the surface of particles within the medium was exhibited successfully using electrochemical sensor system. For the selectivity studies, the results represent that both indicator-based and indicator-free magnetic assays provide a better discrimination for DNA hybridization compared to duplex with one-base or more mismatches. The detection limits (S/N = 3) of the magnetic assays based on indicator or indicator-free were found in nM concentration level of target using disposable sensor technology with good reproducibility. The characterization and advantages of both proposed magnetic assays connected with a disposable electrochemical sensor are also discussed and compared with those methods previously reported in the literature. (c) 2008 Elsevier B.V. All rights reserved.Turkish Scientific and Technological Council (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [106S181]; Turkish Academy of Pharmacists and Turkish Pharmacists Association (TEB)Turkish Academy of Sciences; Czech Academy of SciencesCzech Academy of Sciences [A100040602, A400040804, AV0Z50040702]; Ege UniversityEge University [06/ECZ/002]Authors acknowledge the financial support from Turkish Scientific and Technological Council (TUBITAK; Project No. 106S181), Turkish Academy of Pharmacists and Turkish Pharmacists Association (TEB), support from Grant Agency of the Czech Academy of Sciences (Grant Nos. A100040602 and A400040804, and by institutional grant AV0Z50040702). The experimental work includes the doctoral thesis of H.K. supported by Ege University, Faculty of Pharmacy, project coordination (Project 06/ECZ/002). A.E. would like to express her gratitude to the Turkish Academy of Sciences (TUBA) as the associate member of TUBA for their support. H.K. and F.K. acknowledges a scholarship for Ph.D. students from Scientific and Technical Research Council of Turkey (TUBITAK)

Study of Copper and Purine-Copper Complexes on Modified Carbon Electrodes by Cyclic and Elimination Voltammetry

Using a paraffin impregnated graphite electrode (PIGE) and mercury-modifiedpyrolytic graphite electrode with basal orientation (Hg-PGEb) copper(II) and Cu(II)-DNApurine base solutions have been studied by cyclic (CV) and linear sweep voltammetry(LSV) in connection with elimination voltammetry with linear scan (EVLS). In chlorideand bromide solutions (pH 6), the redox process of Cu(II) proceeded on PIGE with twocathodic and two anodic potentially separated signals. According to the eliminationfunction E4, the first cathodic peak corresponds to the reduction Cu(II) e- → Cu(I) withthe possibility of fast disproportionation 2Cu(I) → Cu(II) Cu(0). The E4 of the secondcathodic peak signalized an electrode process controlled by a surface reaction. Theelectrode system of Cu(II) on Hg-PGEb in borate buffer (pH 9.2) was characterized by onecathodic and one anodic peak. Anodic stripping voltammetry (ASV) on PIGE and cathodicstripping voltammetry (CSV) on Hg-PGEb were carried out at potentials where thereduction of copper ions took place and Cu(I)-purine complexes were formed. By usingASV and CSV in combination with EVLS, the sensitivity of Cu(I)-purine complexdetection was enhanced relative to either ASV or CSV alone, resulting in higher peakcurrents of more than one order of magnitude. The statistical treatment of CE data wasused to determine the reproducibility of measurements. Our results show that EVLS inconnection with the stripping procedure is useful for both qualitative and quantitativemicroanalysis of purine derivatives and can also reveal details of studied electrodeprocesses

Elimination Voltammetry with Linear Scan as a New Detection Method for DNA Sensors

The paper describes successful coupling of adsorptive transfer stripping (AdTS) andelimination voltammetry with linear scan (EVLS) for the resolution of reduction signals of cytosine (C)and adenine (A) residues in hetero-oligodeoxynucleotides (ODNs). Short ODNs (9-mers and 20-mers)were adsorbed from a small volume on a hanging mercury drop electrode (HMDE). After washing ofthe ODN-modified electrode by water and its transferring to an electrochemical cell, voltammetric curves were measured. The AdTS EVLS was able to determine of C/A ratio of ODNs through theelimination function conserving the diffusion current component and eliminating kinetic and chargingcurrent components. This function, which provides the elimination signal in a peak-counterpeak form,increased the current sensitivity for A and C resolution, and for the recognition of bases sequences inODN chains. Optimal conditions of elimination experiments such as pH, time of adsorption, and scanrate were found. The combination of EVLS with AdTS procedure can be considered as a newdetection method in a DNA sensor

Phytochelatin Modified Electrode Surface as a Sensitive Heavy- Metal Ion Biosensor

Electrochemical biosensors have superior properties over other existingmeasurement systems because they can provide rapid, simple and low-cost on-fielddetermination of many biological active species and a number of dangerous pollutants. Inour work, we suggested a new heavy metal biosensor based on interaction of heavy metalions (Cd2+ and Zn2+ ) with phytochelatin, which was adsorbed on the surface of the hangingmercury drop electrode, using adsorptive transfer stripping differential pulse voltammetry.In addition, we applied the suggested technique for the determination of heavy metals in abiological sample – human urine and platinum in a pharmaceutical drug. The detectionlimits (3 S/N) of Cd(II), Zn(II) and cis-platin were about 1.0, 13.3 and 1.9 pmole in 5 μl,respectively. On the basis of the obtained results, we propose that the suggested techniqueoffers simple, rapid, and low-cost detection of heavy metals in environmental, biologicaland medical samples