Abstract:
:The rate constants for the photodynamic inactivation of hen egg-white lysozyme at different temperatures were studied. Arrhenius plots of the methylene blue sensitized photo-inactivation of lysozyme gave an experimental activation energy of 7.5 kcal/mol. The rate constants for the photodynamic inactivation of lysozyme in the presence of riboflavin decreased almost linearly in the temperature range 4-38 degrees C. The photosensitized oxidation of lysozyme at -20 degrees C in freezing and non-freezing solvents was possible only in the presence of riboflavin. The effect of dye concentration on the quantum yield and rate constant for the photodynamic inactivation of lysozyme was examined. The quantum yields were lower when the concentrations of methylene blue used were low, and increased on increasing dye concentration, getting to a maximum and then declined at higher dye concentrations. It was found that in the case of riboflavin sensitized photo-inactivation of lysozyme both the rate constant and the quantum yield increased as the dye concentration increased. No maximum was observed over the range of dye concentrations studied. A new mechanism is postulated for the photodynamic action of lysozyme in the presence of riboflavin.
journal_name
Radiat Environ Biophysjournal_title
Radiation and environmental biophysicsauthors
Silva Edoi
10.1007/BF01326898subject
Has Abstractpub_date
1979-02-23 00:00:00pages
71-9issue
1eissn
0301-634Xissn
1432-2099journal_volume
16pub_type
杂志文章abstract::Large lung sections of humans of advanced adult age revealed a markedly nonuniform retention pattern of dense anthracotic particle aggregates, with an impressive accumulation of this material along pulmonary lymphatics, i.e. the deep (peribronchial), septal (perivenous) and superficial (pleural) networks. Conversely, ...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/BF01221972
更新日期:1987-01-01 00:00:00
abstract::Survival and G2 dalay following exposure to either 60Cobalt-gamma-rays or 241Americium-alpha-particles were studied in eight mammalian cell lines of human and animal origin including human fibroblasts from normal individuals and from patients with Ataxia telangiectasia or Fanconi's anemia. For both endpoints the effec...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/BF01325466
更新日期:1982-01-01 00:00:00
abstract::Results of measurements of the resuspended radioactive aerosols in the Chernobyl area are presented which were obtained soon after the Chernobyl reactor accident and in a European project in 1992-1993. The measurements were carried out with the intention of obtaining a data base for dose assessment of resuspended radi...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/s004110050065
更新日期:1997-09-01 00:00:00
abstract::We examined, by the fluorescent halo assay, alterations in the nucleoid structure (structure formed from cells under mild lysis conditions: in non-ionic detergent Triton X-100, 0.0005% and 1.5 mol/l NaCl) of L5178Y (LY) cell sublines which had been untreated, treated with reducing/chelating agents (beta-mercaptoethano...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/BF01210211
更新日期:1992-01-01 00:00:00
abstract::Activity catalysing double-strand DNA recombination has been investigated in human tumour cell lines using an in vitro assay in which nuclear extracts from tumour cells are used to catalyse homologous recombination between deletion plasmids. The cell lines investigated showed comparable constitutive levels of recombin...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/s004110050056
更新日期:1997-02-01 00:00:00
abstract::Human female lymphocytes were exposed to X-rays in vitro at 7 different doses between 40-280 R. In 830 metaphases chromosome analyses were carried out with either conventional staining or G-banding, respectively. 486 breakpoints are non-randomly distributed between chromosomes and chromosome arms. An excess of lesions...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/BF01340573
更新日期:1979-01-01 00:00:00
abstract::The biophysical characteristics of heavy ions make them a rational source of radiation for use in radiotherapy of malignant tumours. Prior to radiotherapy treatment, a therapeutic regimen must be precisely defined, and during this stage information on individual patient radiosensitivity would be of very great medical ...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/s00411-006-0063-2
更新日期:2006-11-01 00:00:00
abstract::The effect of ionizing irradiation on the physiological activity of cyclic adenosine monophosphate (cAMP) in smooth muscle preparations from frog lung was studied. cAMP, given as dibutyryl salt (dib-cAMP) inhibited the radiation induced contractions of the muscle in a manner similar to the action of theophylline. In v...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/BF01323750
更新日期:1982-01-01 00:00:00
abstract::To investigate whether residual radiation damage in hematopoietic tissue is measurable in situ by a change in cell turnover, the retention of the thymidine analogue 5-(125-I)iodo-2'-deoxyuridine (125-IUdR) following incorporation into DNA of cells in bone marrow and spleen of mice was measured 35 days after 0-500 rad ...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/BF01325468
更新日期:1982-01-01 00:00:00
abstract::The observable responses of living systems to ionizing radiation depend on the level of biological organization studied. Understanding the relationships between the responses characteristic of the different levels of organization is of crucial importance. The main objective of the present study is to investigate how s...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/s00411-011-0382-9
更新日期:2011-11-01 00:00:00
abstract::Fluence spectra at several ground distances in Hiroshima and Nagasaki are provided along with associated fluence-to-kerma coefficients from the Dosimetry System 2002 (DS02). Also included are transmission factors for calculating expected responses of in situ sample measurements of neutron activation products such as (...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/s00411-007-0120-5
更新日期:2007-11-01 00:00:00
abstract::The use of Green's function has played a fundamental role in transport calculations for high-charge high-energy (HZE) ions. Two recent developments have greatly advanced the practical aspects of implementation of these methods. The first was the formulation of a closed-form solution as a multiple fragmentation perturb...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/BF01211542
更新日期:1995-08-01 00:00:00
abstract::In this study, thyroid cancer incidence (follow-up period: 1991-2001) has been analyzed, including persons who were exposed as children at an age between 0 and 17 years and who are living in the Bryansk oblast, the worst contaminated area of Russia after the Chernobyl accident. According to the census of 1989, the pop...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/s00411-006-0039-2
更新日期:2006-05-01 00:00:00
abstract::The Auger electron emitter 123I was examined in the form of 4-[123I]iodoantipyrine and as [123I]NaI for its effectiveness in killing cells of different sensitivity to photon irradiation. Micronucleus assays showed that 4-[123I]iodoantipyrine is 2-3 times more effective in cell inactivation than [123I]NaI. This can be ...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/s004110000083
更新日期:2001-03-01 00:00:00
abstract::Many experimental studies are carried out to compare biological effectiveness of high dose rate (HDR) with that of low dose rate (LDR). The rational for this is the uncertainty regarding the value of the dose rate effectiveness factor (DREF) used in radiological protection. While a LDR is defined as 0.1 mGy/min or low...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/s00411-020-00852-z
更新日期:2020-08-01 00:00:00
abstract::During anthropogenic activities, such as agricultural soil management and traffic on unpaved roads, size distribution measurements were performed of atmospheric particulate radionuclides at a site in the Chernobyl 30-km exclusion zone. Analysis of cascade impactor measurements showed an increase of the total atmospher...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/s004110050118
更新日期:1998-10-01 00:00:00
abstract::Within the track structure code PARTRAC, DNA strand break induction by direct and indirect radiation action was calculated for the E. coli catabolite gene activator protein (CAP) DNA complex with (125)I located at the position of the H(5) atom of the cytosine near the center. The shape of the resulting DNA fragment si...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/s00411-004-0231-1
更新日期:2004-05-01 00:00:00
abstract::The article is devoted to the study of the role of intracellular mechanisms in the formation of radiation-induced genetic instability and its transgenerational effect in cells of different tissues of the descendants of Drosophila melanogaster mutant strains whose parents were exposed to chronic radiation (0.42 and 3.5...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/s00411-020-00833-2
更新日期:2020-05-01 00:00:00
abstract::Combined action of irradiation (IR), shear stress, and high blood pressure is well recognized to induce damage to vasculature, while data on pathological effects of IR in large peripheral vessels with low blood pressure are scarce. The purpose of the present study was hence to investigate time- and dose-dependent effe...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/s00411-013-0492-7
更新日期:2014-03-01 00:00:00
abstract::C57Bl6-lacZ animals were exposed to a range of low dose-rate simulated solar particle event (sSPE) radiation at the NASA-sponsored Research Laboratory (NSRL) at Brookhaven National Laboratory (BNL). Peripheral blood was harvested from animals from 1 to 12 days after total body irradiation (TBI) to quantify the level o...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/s00411-010-0291-3
更新日期:2010-08-01 00:00:00
abstract::For radiation exposures employing targeted sources such as particle microbeams, the deposition of energy and dose will depend on the spatial heterogeneity of the sample. Although cell structural variations are relatively minor for two-dimensional cell cultures, they can vary significantly for fully differentiated tiss...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/s00411-011-0371-z
更新日期:2011-08-01 00:00:00
abstract::Irradiation of human lymphocytes by alpha-particles under different conditions has been seen to be substantially more effective in the induction of dicentric chromosomes than irradiation by gamma-rays. However, the relative biological effectiveness (RBE) determined in these studies differed by a factor of more than 10...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/s004110050028
更新日期:1996-08-01 00:00:00
abstract::Because of the increasing application of ionizing radiation in medicine, quantitative data on effects of low-dose radiation are needed to optimize radiation protection, particularly with respect to cataract development. Using mice as mammalian animal model, we applied a single dose of 0, 0.063, 0.125 and 0.5 Gy at 10 ...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/s00411-017-0728-z
更新日期:2018-05-01 00:00:00
abstract::Monte Carlo codes have been used for approximately 80 years to solve various problems in medical physics. In this paper, the importance of the MCNPX code in treatment planning is highlighted. As illustrative examples of the role of MCNPX in this field, some dosimetric parameters, isodose distribution curves, and figur...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/s00411-020-00841-2
更新日期:2020-05-01 00:00:00
abstract::To explore the expression level and the role of peroxisome proliferator-activated receptor gamma (PPAR-γ) in radiation-induced heart injury in a rat model, thirty-two Sprague-Dawley rats were divided into three groups (the control group, the 15-Gy irradiation group and the 18-Gy irradiation group). Experimental animal...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/s00411-011-0390-9
更新日期:2012-03-01 00:00:00
abstract::This study aimed to evaluate the biological effects of gamma irradiation on zebrafish embryos. Different doses of gamma rays (0.01, 0.05, 0.1, 0.5 and 1 Gy) were used to irradiate zebrafish embryos at three developmental stages (stage 1, 6 h post-fertilization (hpf); stage 2, 12 hpf; stage three, 24 hpf), respectively...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/s00411-016-0663-4
更新日期:2016-11-01 00:00:00
abstract::Frequently knowledge of elemental content of human organs and tissues is required for a variety of applications. These can include brachytherapy and radiotherapy planning, radiation dosimetry and radiation protection. Revised reference values of chemical element mass fractions in normal and cancerous prostate tissues ...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/s00411-020-00884-5
更新日期:2021-01-02 00:00:00
abstract::The risk of cancer after diagnostic X-rays received as fetus or during early childhood has been investigated in many studies. The results of recent epidemiological studies are summarized in a present systematic review. The strategies for literature search, inclusion criteria, and items for study quality assessment wer...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章,评审
doi:10.1007/s00411-008-0171-2
更新日期:2008-07-01 00:00:00
abstract::The TEL1 gene from Saccharomyces cerevisiae has been shown to be the closest sequence homologue to ATM, the gene mutated in ataxia-telangiectasia (A-T) patients. Functional homology shared between the ATM and Tell proteins has recently been demonstrated based on heterologous expression of the TEL1 gene in human cells ...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/s00411-001-0125-4
更新日期:2001-12-01 00:00:00
abstract::It is usually assumed that sparsely ionizing radiation produces randomly distributed DNA breakages. This seems to be supported by the finding that in some DNA fragments single-strand scissions occur uniformly at all nucleotide sites, regardless of sequence. We performed experiments on two DNA fragments of about 300 bp...
journal_title:Radiation and environmental biophysics
pub_type: 杂志文章
doi:10.1007/BF01255271
更新日期:1994-01-01 00:00:00