Lung cancer is one of the most common forms of cancer. The aim of this study was to validate chromosome aberrations in peripheral blood lymphocytes of lung cancer patients living in a region with ...high air pollution and increased background radon levels as a biomarker of cancer risk. A total of 417 lung cancer patients and 468 control participants were analysed using a chromosome aberration assay in peripheral blood lymphocytes. The results showed that chromatid-type aberrations (2.26±1.58 vs. 1.60±1.58) and chromosome-type aberrations (CSAs) (0.96±1.36 vs. 0.42±0.70) in lung cancer patients were increased significantly in comparison with the controls. The most significant two-fold increase was detected for CSAs (nonsmoking patients: 0.84±1.54 vs. 0.41±0.73%, smoking patients: 0.99±1.31 vs. 0.44±0.67%). The frequency of dicentric and ring chromosomes, double minutes and rogue cells was significantly higher (P=0.002, 0.00002, 0.01, 0.0007) in the lung cancer patients. As both analysed groups lived in the same environment, our results show that increased radon levels were not the only source for the detected genome damage. Using binomial logistic regression, the estimated odds ratios and 95% confidence intervals adjusted for the main confounders (smoking, occupational exposure, age) were 1.31 (1.20-1.40) for chromatid-type aberrations, 1.28 (1.17-1.33), and 1.68 (1.49-1.88) for CSAs. It may be suggested that lung cancer patients show a significant increase in genome damage that may be caused by an interplay between exposure and individual low capacity of DNA repair, leading to genome instability.
Purpose
To study the potential links between genetic polymorphisms in the
GSTT1
,
GSTM1, GSTP1
genes and the frequency of chromosomal aberrations (CAs) in lung cancer patients and healthy residents ...in Russian Federation.
Methods
200 cells in well-spread metaphase with 46 chromosomes were examined for 353 newly diagnosed lung cancer patients (males) who received medical treatment in the Kemerovo Regional Oncology Center (Kemerovo, Russian Federation), and 300 healthy males from Kemerovo, Russian Federation. The polymorphisms of the
GSTM1
del and
GSTT1
del genes were analysed by multiplex PCR. Genotyping of the polymorphic variants in the
GSTP1
(
A313G, T341C
) gene was performed using Real-time PCR with competing TaqMan probes complementary to the polymorphic DNA sites. The data analysis was performed using software STATISTICA 8.0 (StatSoft Inc., USA).
Results
We discovered that a
GSTM1
del polymorphism increases the frequency of chromosomal damage in smoking patients with lung cancer, a general group of lung cancer patients, donors with non-small cell lung cancer and patients in the latest stages of the malignant process. The synergetic effects of occupational exposure and the malignant process can induce some modifications in the cytogenetic status in lung cancer patients harbouring the
GSTM1
del polymorphism.
Conclusions
CAs in peripheral blood lymphocytes can be used as biomarkers of the early biological effects of exposure to genotoxic carcinogens and may predict future cancer incidence in several epidemiologic studies. Genetic changes in genes encoding phase II detoxification enzymes are linked to decreases in the metabolic detoxification of environmentally derived genotoxic carcinogens.
In coal mines, workers performing basic production operations underground are exposed to a whole range of both chemical and radiation-induced carcinogenic factors. This leads to a significant ...increase in the risk of lung cancer in underground mine workers. The likelihood of developing cancer is affected by genetically determined features of the body's defense systems. Specifically, much research has been devoted to the role of inherited variants of genes encoding DNA repair enzymes. However, their polymorphism in coal miners remains largely unexplored. The present study investigated associations of the polymorphism of genes encoding DNA repair enzymes - hOGG1 (rs1052133), APEX1 (rs1130409), XPD (rs13181), NBS 1 (rs1805794), and ADPRT1 (rs1136410) - with the risk of developing lung cancer in coal miners. Two hundred and thirteen miners with lung cancer were examined. The control group included 247 healthy miners of the Kemerovo Region (Western Siberia, Kuzbass). Genotyping was performed using allele-specific PCR. The study showed that the following gene variants were associated with the risk of developing cancer: polymorphism of the genes APEX1 (dominant model: ORadj=1.71; CI 95 %: 1.04-2.81), XPD (dominant model: ORadj=2.12; CI 95 %: 1.30-3.46), and ADPRT1 (recessive model: ORadj=3.00; CI 95 %: 1.08-8.33). The results of this work suggest the relationship between the polymorphism of the genes of DNA repair enzymes and the risk of lung cancer in coal mine workers.
Two new species of the genus Isochlora Staudinger, 1882 are described: I. hreblayi Volynkin, Tth, Titov & Saldaitis, sp. n. (western Mongolia) and I. kozlovi Volynkin, Titov, Matov & Saldaitis, sp. ...n. (Qinghai Province, China). The type species of the genus-group names Chamyla Staudinger, 1900 and Grumia Alphraky, 1892 (I. arctomys Alphraky, 1897 and I. flora (Alphraky, 1892), respectively) are examined, and their synonymy with Isochlora is revised. The synonymy of Chamyla idia Staudinger, 1900 with Isochlora arctomys Alphraky, 1897 is revised as junior synonymies. Lectotypes are designated for Isochlora arctomys Alphraky, 1897, Chamyla idia Staudinger, 1900 and Grumia flora Alphraky, 1892. Isochlora intricans (Alphraky, 1882) is reported from Kazakhstan for the first time. Adults as well as male and female genitalia are illustrated.
We have investigated the photoactivated O2 adsorption/desorption, the isotope equilibration (POIEq), and the isotope exchange (POIEx) in the O2–(TiO2–x /TiO2) (Degussa P-25) system, as well as the ...adsorption and POIEx in the NO–(TiO2–x /TiO2) systems. The photoactivation spectra of the hole centers Os – generation, of POIEq, and of the NO photoadsorption were measured in the 300–500 nm range using a continuously adjustable wavelength light source. The spectral characteristics of the NO photoadsorption are close to those of POIEq Both electron-donor and hole centers are manifested in these processes. For O2 photodesorption, CO oxidation, POIEx, and POIEq the hole centers Os – are responsible. In the case of O2 and NO photoadsorption both types of centers are active. The maxima of POIEq and of NO photoadsorption are placed near 420 nm beyond the edge of the TiO2 bandgap absorption. It was found that not only does the N18O–Ti16O2 exchange occurs under the illumination but also it can be activated by a preliminary sample illumination in vacuum as it was observed for POIEq. The photoactivation spectrum does not coincide with the absorption spectra of the F-type centers (F+ and F-centers, i.e., oxygen anion vacancies filled with one or two e–, respectively) and of Ti3+. The formation of the 2D structures, “core–shell” TiO2–x /TiO2, on the parts of the surface region and the decreasing of bandgap on these parts are supposed based on the kinetic data (the “fast” excitations in the bulk under UV irradiation and the “slow” excitations on the surface under the visible irradiation) and on the spectral data (maximum action is near 420 nm for both electronic and hole centers).
The article proposes a scheme of the process of manufacturing bimetallic tubular elements by extraction a cylindrical cup of two dissimilar metals without thinning and extraction with thinning cup. ...At the same time, in the process of extraction in the heated state, the layers of dissimilar metals and alloys are connected and the desired shape of the product is obtained. A mathematical model of deformation of the process of joint extraction with thinning of two dissimilar metals with heating in a flat deformed state is developed. The influence of the deformation value on the dispersion of mechanical energy by bimetal was revealed.
A complex technique of theoretical and experimental research of the process of manufacturing bimetallic tubular elements by drawing with thinning of a two-layer billet of dissimilar metals using the ...relief of the boundary surface is presented. Using the theory of plastic flow, a mathematical model was developed for the deformation of the joint drawing process with thinning of two dissimilar metals with heating under conditions of a plane deformed state, which allowed to establish the relationship between the parameters of the stress-strain state on the boundary surface and the degree of deformation of the thinning with the original geometric parameters of the workpiece to fill the relief of the boundary surface
The interaction of oxygen molecules with TiO2 (Degussa P25) surface under UV (λ = 365 nm) and vis (λ = 436 nm) irradiation at T = 293 K was investigated by means of mass-spectrometry and ...thermo-programmed desorption (TPD) spectroscopy. Oxygen chemisorbed on reduced TiO2 surface consists of molecular species O2 – and atomic ones. The adsorbed O2 species which are stable at 293 K are not observed on oxidized TiO2. The UV or vis irradiation in 18O enriched oxygen induces an intensive photostimulated oxygen isotope equilibration (POIEq) and exchange (POIEx) via a weakly bonded intermediate O3 – due to the interaction of 18O2 with a hole center O s – (which is an exchangeable anion O s 2– that captured a photogenerated hole h + ). The number of surface exchangeable oxygen anions is ∼2 × 1011 cm–2 for oxidized TiO2 and ∼108 cm–2 for reduced TiO2. There is a reason to consider the observed POIEq as a multiple interaction of O s – with 18O2 molecules (in fact by means of heteroexchange). Thus, the obtained POIEq rate corresponds to the number of O s – centers, while the POIEx rate is proportional to the rate of O s – formation. The kinetics of activation/deactivation of O s – in POIEq was studied in the flow-through mode (at 10–6–10–3 Torr). Under vis irradiation, the hole centers O s – are formed in noticeable quantities and live for hundreds of seconds at T = 293 K, while the UV light transforms only a small part of all possible O s 2– into O s –. The lifetime of the latter is short. The lifetime of O s – reduces with the increase of temperature or O2 pressure. Two pathways of O s – deactivation are supposed: the first one includes the recombination of O s – with an electron with an estimated energetic barrier E des = (0.35 ± 0.06) eV; and the second one is a result of collision of intermediate O3 – with gaseous O2.
PDF
