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81.
Chemeris NK Gapeyev AB Sirota NP Gudkova OY Kornienko NV Tankanag AV Konovalov IV Buzoverya ME Suvorov VG Logunov VA 《Mutation research》2004,558(1-2):27-34
Till the present time, the genotoxic effects of high peak-power pulsed electromagnetic fields (HPPP EMF) on cultured cells have not been studied. We investigated possible genotoxic effects of HPPP EMF (8.8 GHz, 180 ns pulse width, peak power 65 kW, repetition rate 50 Hz) on erythrocytes of the frog Xenopus laevis. We used the alkaline comet assay, which is a highly sensitive method to assess DNA single-strand breaks and alkali-labile lesions. Blood samples were exposed to HPPP EMF for 40 min in rectangular wave guide. The specific absorption rate (SAR) calculated from temperature kinetics was about 1.6 kW/kg (peak SAR was about 300 MW/kg). The temperature rise in the blood samples at steady state was 3.5 +/- 0.1 degrees C. The data show that the increase in DNA damage after exposure of erythrocytes to HPPP EMF was induced by the rise in temperature in the exposed cell suspension. This was confirmed in experiments in which cells were incubated for 40 min under the corresponding temperature conditions. The results allow us to conclude that HPPP EMF-exposure at the given modality did not cause any a-thermal genotoxic effect on frog erythrocytes in vitro. 相似文献
82.
Ihab?AB?Awad Christian?A?Rees Tina?Hernandez-Boussard Catherine?A?Ball Gavin?SherlockEmail author 《BMC bioinformatics》2004,5(1):151
Background
Microarray-based comparative genome hybridization experiments generate data that can be mapped onto the genome. These data are interpreted more easily when represented graphically in a genomic context. 相似文献83.
Jennifer H Humphreys Jessica AB van Nies Jackie Chipping Tarnya Marshall Annette HM van der Helm-van Mil Deborah PM Symmons Suzanne MM Verstappen 《Arthritis research & therapy》2014,16(6)
Introduction
This study aimed to investigate rheumatoid factor (RF) and anti-citrullinated protein antibody (ACPA) status and levels as predictors of mortality in two large cohorts of patients with early inflammatory arthritis (EIA).Methods
Data from the Norfolk Arthritis Register (NOAR) and Leiden Early Arthritis Clinic (EAC) cohorts were used. At baseline, patients had demographic data and smoking status recorded; RF, ACPA and inflammatory markers were measured in the local laboratories. Patients were flagged with national death registers until death or censor date. Antibody status was stratified as negative, low or high positive by RF and ACPA levels individually. In addition, patients were grouped as seronegative, RF positive, ACPA positive or double antibody (RF and ACPA) positive. Cox regression models explored associations between antibody status and mortality adjusting for age, sex, smoking status, inflammatory markers and year of enrolment.Results
A total of 4962 patients were included, 64% were female. Median age at onset was 56 (NOAR) and 54 (EAC) years. In NOAR and EAC respectively, 35% and 42% of patients were ACPA/RF positive. When antibody status was stratified as negative, low or high positive, there were no consistent findings between the two cohorts. Double antibody positivity was associated with excess mortality in both cohorts compared to seronegative patients: NOAR and EAC respective adjusted HR (95% confidence interval) 1.35 (1.09 to 1.68) and 1.58 (1.16 to 2.15).Conclusions
Patients with EIA who are seropositive for both RF and ACPA have increased mortality compared to those who are single positive or seronegative. Antibody level in seropositive patients was not consistently associated with excess mortality.Electronic supplementary material
The online version of this article (doi:10.1186/s13075-014-0483-3) contains supplementary material, which is available to authorized users. 相似文献84.
Using the alkaline single cell gel electrophoresis technique (comet assay), changes in chromatin structure of peripheral blood
leukocytes and peritoneal neutrophils have been studied in mice exposed to low-intensity extremely high-frequency electromagnetic
radiation (42.2 GHz, 0.1 mW/cm2, 20 min at 1 h after induction of inflammation) against the background of the systemic inflammatory process. It was revealed
that the exposure of mice with the developing inflammation leads to a pronounced decrease in the level of DNA damage to peripheral
blood leukocytes and peritoneal neutrophils. It is supposed that the changes in the chromatin structure of lymphoid cells
have a genoprotective character in the inflammatory process and can underlie the mechanisms of realization of antiinflammatory
effects of the electromagnetic radiation. 相似文献
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86.
5-Aminolevulinic acid (ALA), a precursor of porphyrin synthesis, increased the production of various porphyrin compounds in Candida guilliermondii cells. Metalloporphyrins and protoporphyrin IX (PPIX) were predominantly accumulated, respectively, at ALA concentrations of 0.2-0.4 mM and at those higher than 1.5 mM. 2,2;-Dipyridyl which complexed with bivalent metals significantly increased the content of endogenous PPIX even at ALA concentrations lower than 0.5 mM. Under these conditions, the yeast sensitivity to photodynamic effect of visible light (400-600 nm) dramatically increased due to photosensitization by endogenous PPIX. 相似文献
87.
The damaging effects of light that was emitted by a DRSh250-3 mercury lamp on the DNA of mouse blood leukocytes was studied in vitro. It was shown that the main DNA damage is due to the action of UVB radiation (280–320 nm). Under the combined effects of the UV radiation and the orange–red fluorescent component it was found that the additional fluorescent light with the spectral maximum at 625 nm from nanoluminophore materials (quantum dots that are based on CdSe/ZnS, CdSe/CdS/ZnS) protected the cellular DNA from the damaging effect of UV radiation. Using nanomolar concentrations of hydrogen peroxide, the hypothesis of the role of reactive oxygen species in the protective effects of the red–orange light was tested in vitro. It was shown for the first time that the mechanisms of the protective effects are associated with the induction of an adaptive response by nanomolar concentrations of hydrogen peroxide that are induced by the orange–red light. 相似文献