The unique feature of nuclear accidents with neutron exposure is the induced radioactivity in body tissues. For dosimetry purposes, the most important stable isotopes occurring in human body, which can be activated by neutrons, are 23 Na and 32 S. The respective activation reactions are as follows:23Na(n,γ)24Na and32S(n,p)32P. While sodium occurs in human blood, sulfur is present in human hair. In order to verify the practical feasibility of this dosimetry technique in conditions of our laboratory, samples of human blood and hair were irradiated in a channel of a training reactor VR-1.24Na activity was measured by gamma-ray spectrometry.32P activity in hair was measured by means of a proportional counter. Based on neutron-spectrum calculation, relationships between neutron dose and induced activity were derived for both blood and hair.
- MeSH
- dávka záření MeSH
- krev účinky záření MeSH
- lidé MeSH
- neutrony * MeSH
- radioaktivita MeSH
- radioizotopy fosforu analýza MeSH
- radioizotopy sodíku MeSH
- radiometrie metody MeSH
- síra analýza MeSH
- sodík analýza MeSH
- únik radioaktivních látek MeSH
- vlasy, chlupy účinky záření MeSH
- záření gama MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
Autologous cell therapy (ACT) is a new treatment method for diabetic patients with critical limb ischemia (CLI) not eligible for standard revascularization. After intramuscular injection of bone marrow-derived mononuclear cells local arteriogenesis in the ischemic tissue occurs. Studies assessing visualization of this therapeutic vasculogenesis after ACT by novel imaging techniques are lacking. The aim of our study was to assess the effect of ACT on possible metabolic changes and perfusion of critically ischemic limbs using (31)P magnetic resonance spectroscopy ( (31)P MRS) and its possible correlation with changes of transcutaneous oxygen pressure (TcPO(2)). Twenty-one patients with diabetes and no-option CLI treated by ACT in our foot clinic over 8 years were included in the study. TcPO(2) as well as rest (phosphocreatine, adenosine triphosphate and inorganic phosphate) and dynamic (mitochondrial capacity and phosphocreatine recovery time) (31)P-MRS parameters were evaluated at baseline and 3 months after cell treatment. TcPO(2) increased significantly after 3 months compared with baseline (from 22.4±8.2 to 37.6±13.3 mm Hg, p=0.0002). Rest and dynamic (31)P MRS parameters were not significantly different after ACT in comparison with baseline values. Our study showed a significant increase of TcPO(2) on the dorsum of the foot after ACT. We did not observe any changes of rest or dynamic (31)P MRS parameters in the area of the proximal calf where the cell suspension has been injected into.
- MeSH
- autologní transplantace metody MeSH
- bérec diagnostické zobrazování krevní zásobení patologie MeSH
- ischemie diagnostické zobrazování metabolismus terapie MeSH
- lidé MeSH
- magnetická rezonanční spektroskopie metody MeSH
- následné studie MeSH
- radioizotopy fosforu MeSH
- transplantace kostní dřeně MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
Neutron field from the p+Be interaction was investigated at the NPI CAS for a proton beam energy of 35 MeV and thick beryllium target. Broad neutron spectra at close source-to-sample distances were determined using the multi-foil activation technique. Two large sets of dosimetry foils containing the Ni, Co, Au, In, Ti, Al, Y, Lu, Nb and Fe were irradiated at a distance of 74 mm at direct neutron beam axis and at a distance of 34 mm from beam axis. Supporting Monte-Carlo MCNPX calculations of the irradiation system were performed as well. From measured reaction rates, the neutron energy spectra at both positions were reconstructed employing the modified version of the SAND-II unfolding code and activation cross-section data from the EAF-2010 library. At the position of irradiated samples, the total fast neutron flux reaches the value up to 1010 cm-2 s-1, and the neutron field is utilizable for radiation hardness study and integral benchmark experiments within the International Fusion Material Irradiation Facility (IFMIF) program.
PURPOSE: To study theoretically the impact on cell survival of the radionuclide uptake rate inside tumor cells for a single administration of a radiopharmaceutical. METHODS: The instantaneous-uptake model of O'Donoghue ["The impact of tumor cell proliferation in radioimmunotherapy," Cancer 73, 974-980 (1994)] for a proliferating cell population irradiated by an exponentially decreasing dose-rate is here extended to allow for the monoexponential uptake of the radiopharmaceutical by the targeted cells. The time derivative of the survival curve is studied in detail deducing an expression for the minimum of the surviving fraction and the biologically effective dose (BED). RESULTS: Surviving fractions are calculated over a parameter range that is clinically relevant and broad enough to establish general trends. Specifically, results are presented for the therapy radionuclides Y-90, I-131, and P-32, assuming uptake half-times 1-24 h, extrapolated initial dose-rates 0.5-1 Gy h(-1), and a biological clearance half-life of seven days. Representative radiobiological parameters for radiosensitive and rapidly proliferating tumor cells are used, with cell doubling time equal to 2 days and α-coefficient equal to 0.3 and 0.5 Gy(-1). It is shown that neglecting the uptake phase of the radiopharmaceutical (i.e., assuming instantaneous-uptake) results in a sizeable over-estimation of cell-kill (i.e., under-estimation of cell survival) even for uptake half-times of only a few hours. The differences between the exponential-uptake model and the instantaneous-uptake model become larger for high peak dose-rates, slow uptakes, and (slightly) for long-lived radionuclides. Moreover, the sensitivity of the survival curve on the uptake model was found to be higher for the tumor cells with the larger α-coefficient. CONCLUSIONS: The exponential-uptake rate of the radiopharmaceutical inside targeted cells appears to have a considerable effect on the survival of a proliferating cell population and might need to be considered in radiobiological models of tumor cell-kill in radionuclide therapy.
- MeSH
- analýza přežití MeSH
- antitumorózní látky farmakokinetika farmakologie MeSH
- biologické modely MeSH
- nádory farmakoterapie patofyziologie MeSH
- proliferace buněk účinky léků MeSH
- radiofarmaka farmakokinetika farmakologie MeSH
- radioizotopy fosforu farmakokinetika farmakologie MeSH
- radioizotopy jodu farmakokinetika farmakologie MeSH
- viabilita buněk účinky léků fyziologie MeSH
- vztah dávky záření a odpovědi MeSH
- yterbium farmakokinetika farmakologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: Ellipticine and doxorubicin are antineoplastic agents, whose action is based mainly on DNA damage such as intercalation, inhibition of topoisomerase II and formation of covalent DNA adducts. The key target to resolve which of these mechanisms are responsible for ellipticine and doxorubicin anticancer effects is the development of suitable methods for identifying their individual DNA-damaging effects. Here, the (32)P-postlabeling method was tested to detect covalent DNA adducts formed by ellipticine and doxorubicin. METHODS: The standard procedure of (32)P-postlabeling assay, this procedure under ATP-deficient conditions, the version using extraction of adducts with n-butanol and the nuclease P1 enrichment version were used to analyze ellipticineand/ or doxorubicin-derived DNA adducts. RESULTS: Two covalent ellipticine-derived DNA adducts, which are associated with cytotoxicity of ellipticine to human UKF-NB-3 and UKF-NB-4 neuroblastoma cell lines, were detected by the (32)P-postlabeling method. These adducts are identical to those formed by the ellipticine metabolites, 13-hydroxy- and 12-hydroxyellipticine. In contrast, no covalent adducts formed by doxorubicin in DNA of these neuroblastoma cells and in DNA incubated with this drug and formaldehyde in vitro were detectable by the (32)P-postlabeling assay. CONCLUSIONS: The results presented in this paper are the first to demonstrate that in contrast to covalent DNA adducts formed by ellipticine, the adducts generated by formaldehyde-mediated covalent binding of doxorubicin to DNA are not detectable by the (32)P-postlabeling assay. No DNA adducts were, detectable either in vitro, in incubations of DNA with doxorubicin or in DNA of neuroblastoma cells treated with this drug. The results also suggest that covalent binding of ellipticine to DNA of UKF-NB-3 and UKF-NB-4 neuroblastoma cell lines is the predominant mechanism responsible for the cytotoxicity of this drug. To understand the mechanisms of doxorubicin anticancer effects on neuroblastoma cells, development of novel methods for identifying covalent doxorubicin-derived DNA adducts is the major challenge for further research.
- MeSH
- adukty DNA analýza MeSH
- antitumorózní látky farmakologie MeSH
- doxorubicin farmakologie MeSH
- elipticiny farmakologie MeSH
- izotopové značení MeSH
- lidé MeSH
- nádorové buněčné linie MeSH
- neuroblastom metabolismus MeSH
- radioizotopy fosforu MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
OBJECTIVES: Ellipticine is a potent antineoplastic agent exhibiting multiple mechanisms of action with promising brain tumor specificity. This anticancer agent should be considered a pro-drug, whose pharmacological efficiency and/or genotoxic side effects are dependent on its cytochrome P450 (CYP) - and/or peroxidase-mediated activation to species forming covalent DNA adducts. Ellipticine can also act as an inhibitor or inducer of biotransformation enzymes, thereby modulating its own metabolism leading to its genotoxic and pharmacological effects. The toxicity of ellipticine to U87MG glioblastoma cells and mechanisms of its action to these cells are aims of this study. METHODS: Ellipticine metabolites formed in U87MG cells were analyzed using HPLC. Covalent DNA modifications by ellipticine were detected by 32P-postlabeling. CYP enzyme expression was examined by QPCR and Western blot. RESULTS: U87MG glioblastoma cell proliferation was efficiently inhibited by ellipticine. This effect might be associated with formation of two covalent ellipticine-derived DNA adducts, identical to those formed by 13-hydroxy- and 12-hydroxyellipticine, the ellipticine metabolites generated by CYP1A1, 1B1 and 3A4, lactoperoxidase and cyclooxygenase 1, the enzymes expressed in U87MG cells. Moreover, by inducing CYP1B1, 3A4 and 1A1 enzymes in U87MG cells, ellipticine increases its own enzymatic activation, thereby enhancing its own genotoxic and pharmacological potential in these cells. Ellipticine concentration used for U87MG cell treatment is extremely important for its pharmacological effects, as its metabolite profiles differed substantially predicting ellipticine to be either detoxified or activated. CONCLUSION: The results found in this study are the first report showing cytotoxicity and DNA adduct formation by ellipticine in glioblastomas.
- MeSH
- adukty DNA metabolismus MeSH
- antitumorózní látky aplikace a dávkování metabolismus farmakologie MeSH
- autoradiografie MeSH
- elipticiny aplikace a dávkování metabolismus farmakologie MeSH
- glioblastom farmakoterapie metabolismus patologie MeSH
- lidé MeSH
- messenger RNA metabolismus MeSH
- nádorové buněčné linie MeSH
- polymerázová řetězová reakce MeSH
- proliferace buněk účinky léků MeSH
- radioizotopy fosforu MeSH
- systém (enzymů) cytochromů P-450 metabolismus MeSH
- viabilita buněk účinky léků MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- western blotting MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Ellipticine is an antineoplastic agent, which forms covalent DNA adducts mediated by cytochromes P450 (CYP) and peroxidases. We evaluated the role of hepatic versus extra-hepatic metabolism of ellipticine, using the HRN (Hepatic Cytochrome P450 Reductase Null) mouse model, in which cytochrome P450 oxidoreductase (POR) is deleted in hepatocytes, resulting in the loss of essentially all hepatic CYP function. HRN and wild-type (WT) mice were treated i.p. with 1 and 10 mg/kg body weight of ellipticine. Multiple ellipticine-DNA adducts detected by (32)P-postlabelling were observed in organs from both mouse strains. Highest total DNA binding levels were found in liver, followed by lung, kidney, urinary bladder, colon and spleen. Ellipticine-DNA adduct levels in the liver of HRN mice were up to 65% lower relative to WT mice, confirming the importance of CYP enzymes for the activation of ellipticine in livers, recently shown in vitro with human and rat hepatic microsomes. When hepatic microsomes of both mouse strains were incubated with ellipticine, ellipticine-DNA adduct levels with WT microsomes were up to 2.9-fold higher than with those from HRN mice. The ratios of ellipticine-DNA adducts in extra-hepatic organs between HRN and WT mice of up to 4.7 suggest that these organs can activate ellipticine and that more ellipticine is available in the circulation. These results and the DNA adduct patterns found in vitro and in vivo demonstrate that both CYP1A or 3A and peroxidases participate in activation of ellipticine to reactive species forming DNA adducts in the mouse model used in this study.
- MeSH
- adukty DNA analýza metabolismus MeSH
- antitumorózní látky metabolismus toxicita MeSH
- cytochrom P-450 CYP1A1 metabolismus MeSH
- cytochrom P-450 CYP3A metabolismus MeSH
- DNA metabolismus účinky léků MeSH
- elipticiny metabolismus toxicita MeSH
- hepatocyty enzymologie účinky léků MeSH
- injekce intraperitoneální MeSH
- izotopové značení metody MeSH
- jaterní mikrozomy enzymologie účinky léků MeSH
- játra enzymologie účinky léků MeSH
- myši inbrední C57BL MeSH
- myši knockoutované MeSH
- myši MeSH
- NADPH-cytochrom c-reduktasa genetika metabolismus nedostatek MeSH
- radioizotopy fosforu MeSH
- umlčování genů MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- myši MeSH
- zvířata MeSH
3-Nitrobenzanthrone (3-NBA) is a carcinogen occurring in diesel exhaust and air pollution. Using the (32)P-postlabelling method, we found that 3-NBA and its human metabolite, 3-aminobenzanthrone (3-ABA), are activated to species forming DNA adducts by cytosols and/or microsomes isolated from rat lung, the target organ for 3-NBA carcinogenicity, and kidney. Each compound generated identical five DNA adducts. We have demonstrated the importance of pulmonary and renal NAD(P)H:quinone oxidoreductase (NQO1) to reduce 3-NBA to species that are further activated by N,O-acetyltransferases and sulfotransferases. Cytochrome P450 (CYP) 1A1 is the essential enzyme for oxidative activation of 3-ABA in microsomes of both organs, while cyclooxygenase plays a minor role. 3-NBA was also investigated for its ability to induce NQO1 and CYP1A1 in lungs and kidneys, and for the influence of such induction on DNA adduct formation by 3-NBA and 3-ABA. When cytosols from rats treated i.p. with 40mg/kg bw of 3-NBA were incubated with 3-NBA, DNA adduct formation was up to 2.1-fold higher than in incubations with cytosols from control animals. This increase corresponded to an increase in protein level and enzymatic activity of NQO1. Incubations of 3-ABA with microsomes of 3-NBA-treated rats led to up to a fivefold increase in DNA adduct formation relative to controls. The stimulation of DNA adduct formation correlated with the potential of 3-NBA to induce protein expression and activity of CYP1A1. These results demonstrate that 3-NBA is capable to induce NQO1 and CYP1A1 in lungs and kidney of rats thereby enhancing its own genotoxic and carcinogenic potential.
- MeSH
- adukty DNA metabolismus MeSH
- benz(a)anthraceny farmakologie toxicita MeSH
- cytochrom P-450 CYP1A1 metabolismus účinky léků MeSH
- cytosol metabolismus účinky léků MeSH
- enzymová indukce MeSH
- financování organizované MeSH
- jaterní mikrozomy metabolismus účinky léků MeSH
- karcinogeny farmakologie toxicita MeSH
- krysa rodu rattus MeSH
- látky znečišťující životní prostředí farmakologie toxicita MeSH
- ledviny metabolismus účinky léků MeSH
- mutageny farmakologie toxicita MeSH
- NAD(P)H dehydrogenasa (chinon) metabolismus účinky léků MeSH
- plíce metabolismus účinky léků MeSH
- potkani Wistar MeSH
- radioizotopy fosforu MeSH
- testy genotoxicity MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- MeSH
- bolest etiologie MeSH
- kvalita života MeSH
- lidé MeSH
- management bolesti MeSH
- metastázy nádorů radioterapie terapie MeSH
- nádory kostí etiologie radioterapie terapie MeSH
- paliativní péče metody využití MeSH
- radioizotopy fosforu aplikace a dávkování terapeutické užití MeSH
- radioizotopy stroncia aplikace a dávkování terapeutické užití MeSH
- radionuklidy aplikace a dávkování terapeutické užití MeSH
- radium aplikace a dávkování terapeutické užití MeSH
- rhenium aplikace a dávkování terapeutické užití MeSH
- samarium aplikace a dávkování terapeutické užití MeSH
- Check Tag
- lidé MeSH
This study describes urinary excretion of two nucleobase adducts derived from styrene 7,8-oxide (SO), i.e., 7-(2-hydroxy-1-phenylethyl)guanine (N7alphaG) and 7-(2-hydroxy-2-phenylethyl)guanine (N7betaG), as well as a formation of N7-SO-guanine adducts in lungs and liver of two month old male NMRI mice exposed to styrene by inhalation in a 3-week subacute study. Strikingly higher excretion of both isomeric nucleobase adducts in the first day of exposure was recorded, while the daily excretion of nucleobase adducts in following time intervals reached the steady-state level at 4.32+1.14 and 6.91+1.17 pmol/animal for lower and higher styrene exposure, respectively. beta-SO-guanine DNA adducts in lungs increased with exposure in a linear way (F=13.7 for linearity and 0.17 for non-linearity, respectively), reaching at the 21st day the level of 23.0 adducts/10(8) normal nucleotides, i.e., 0.74 fmol/microg DNA of 7-alkylguanine DNA adducts for the concentration of 1500 mg/m3, while no 7-SO-guanine DNA adducts were detected in the liver after 21 days of inhalation exposure to both of styrene concentrations. A comparison of 7-alkylguanines excreted in urine with 7-SO-guanines in lungs (after correction for depurination and for missing alpha-isomers) revealed that persisting 7-SO-guanine DNA adducts in lungs account for about 0.5% of the total alkylation at N7 of guanine. The total styrene-specific 7-guanine alkylation accounts for about 1.0x10(-5)% of the total styrene uptake, while N1-adenine alkylation contributes to this percentage only negligibly.
- MeSH
- adukty DNA analýza moč MeSH
- hmotnostní spektrometrie s elektrosprejovou ionizací MeSH
- inbrední kmeny myší MeSH
- inhalační expozice MeSH
- játra metabolismus účinky léků MeSH
- myši MeSH
- plíce metabolismus účinky léků MeSH
- radioizotopy fosforu MeSH
- styren farmakokinetika toxicita MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- myši MeSH
- zvířata MeSH
