A novel analytical brain block tool to enable functional annotation of discriminatory transcript biomarkers among discrete regions of the fronto-limbic circuit in primate brain.

Fronto-limbic circuits in the primate brain are responsible for executive function, learning and memory, and emotions, including fear. Consequently, changes in gene expression in cortical and subcortical brain regions housing these circuits are associated with many important psychiatric and neurological disorders. While high quality gene expression profiles can be identified in brains from model organisms, primate brains have unique features such as Brodmann Area 25, which is absent in rodents, yet profoundly important in primates, including humans.

Telomere instability caused by subtelomeric Y' amplification and rearrangements in Saccharomyces cerevisiae (ku70 tel1 and ku70 rad50) double mutants.

Telomeres solve the end-replication problem. Previous results suggested a relation between Yku70/80 and proteins Tell and Rad50 in telomere stabilization. Inactivation of any of these genes lead to a shortening of telomeres, while in ku70 tell or ku70 rad50 double mutants a drastic amplification of Y' elements was found.

Efficacy of eradicative radiotherapy for limited nodal metastases detected with choline PET scan in prostate cancer patients.

Aims And Background: In patients with recurrent prostate cancer, discriminating local or systemic recurrence is critical to decide second-line treatment. We investigated the capability of stereotactic body radiotherapy to treat limited nodal recurrences, detected using choline PET scan.

Methods And Study Design: Seventy-one patients with biochemical failure were studied after prostate cancer treatment: prostatectomy (28), radiotherapy (15) or both (28).

Stereotactic radiotherapy for adrenal gland metastases: university of Florence experience.

Purpose: To evaluate a retrospective single-institution outcome after hypofractionated stereotactic body radiotherapy (SBRT) for adrenal metastases.

Methods And Materials: Between February 2002 and December 2009, we treated 48 patients with SBRT for adrenal metastases. The median age of the patient population was 62.

(41)Ca in tooth enamel. Part I: a biological signature of neutron exposure in atomic bomb survivors.

The detection of (41)Ca atoms in tooth enamel using accelerator mass spectrometry is suggested as a method capable of reconstructing thermal neutron exposures from atomic bomb survivors in Hiroshima and Nagasaki. In general, (41)Ca atoms are produced via thermal neutron capture by stable (40)Ca. Thus any (41)Ca atoms present in the tooth enamel of the survivors would be due to neutron exposure from both natural sources and radiation from the bomb.

Influence of the bystander phenomenon on the chromosome aberration pattern in human lymphocytes induced by in vitro alpha-particle exposure.

A recent publication on both chromosome-type and chromatid-type aberrations in lymphocytes of patients during treatment with radium-224 for ankylosing spondilitis has revived the question of whether the chromatid-type aberrations may be the consequence of factors released by irradiated cells. Therefore, the aim of the present study was to investigate the influence of such a bystander phenomenon on the chromosome aberration pattern of lymphocytes. Monolayers of human lymphocytes were irradiated with 1 Gy of alpha-particles from an americium-241 source in the absence or presence of whole blood, autologous plasma or culture medium.

Dose-response relationship of dicentric chromosomes in human lymphocytes obtained for the fission neutron therapy facility MEDAPP at the research reactor FRM II.

The biological effectiveness of neutrons from the neutron therapy facility MEDAPP (mean neutron energy 1.9 MeV) at the new research reactor FRM II at Garching, Germany, has been analyzed, at different depths in a polyethylene phantom. Whole blood samples were exposed to the MEDAPP beam in special irradiation chambers to total doses of 0.

Investigation of some parameters influencing the sensitivity of human tooth enamel to gamma radiation using electron paramagnetic resonance.

Electron paramagnetic resonance (EPR) has been successfully used as a physical technique for gamma radiation dose reconstruction using calcified tissues. To minimize potential discrepancies between EPR readings in future studies, the effects of cavity response factor, tooth position and donor gender on the estimated gamma radiation dose were studied. It was found that the EPR response per sample mass used for assessment of doses in teeth outside of the 70-100 mg range should be corrected by a factor which is a function of the sample mass.

The depth-dependence of the biological effectiveness of 60Co gamma rays in a large absorber determined by dicentric chromosomes in human lymphocytes.

Radiobiological evidence is shown concerning a significant depth-dependence of the maximum relative biological effectiveness at limiting low doses (RBE(M)) of (60)Co gamma rays in a cubic polymethylmethacrylate (PMMA) phantom of 30 cm edge length. Using the dose-response curve for the dicentric data in human lymphocytes obtained in the present experiment at a depth of 20 cm, together with the comprehensive and consistent data set determined earlier at smaller depths of the PMMA phantom, there is an increase in the RBE(M) value by a factor of 2.18 +/- 1.

Relevance of biologically equivalent dose values in outcome evaluation of stereotactic radiotherapy for lung nodules.

Purpose: Different biologically equivalent dose (BED) values associated with stereotactic radiotherapy (SRT) of patients with primary and metastatic pulmonary nodules were studied. The BED values were calculated for tumoral tissue and low alpha/beta ratio, assuming that better local response could be obtained by using stereotactic high-BED treatment.

Methods And Materials: Fifty-eight patients with T1-T3 N0 non-small-cell lung cancer and 46 patients with metastatic lung nodules were treated with SRT.

Additional criteria for EPR dosimetry using tooth enamel.

Currently, EPR measurements are based on the assumption that odontogenesis (the series of events between the bud formation stage until the complete maturation of the tooth) is finished as soon as the tooth erupts. Consequently, it is also assumed that the hydroxyapatite concentration of the enamel (source of free radicals) does not depend on tooth age. However, the present work provides evidence that odontogenesis does not end after tooth eruption but continues for several years after eruption.

The effect of the beta-emitting yttrium-90 citrate on the dose-response of dicentric chromosomes in human lymphocytes: a basis for biological dosimetry after radiosynoviorthesis.

The production of dicentric chromosomes in human lymphocytes by beta-particles of yttrium-90 (Y-90) was studied in vitro to provide a basis of biological dosimetry after radiosynoviorthesis (RSO) of persistent synovitis by intra-articular administration of yttrium-90 citrate colloid. Since the injected colloid may leak into the lymphatic drainage exposing other parts of the body to radiation, the measurement of biological damage induced by beta-particles of Y-90 is important for the assessment of radiation risk to the patients. A linear dose-response relationship (alpha = 0.

Indications of the neutron effect contribution in the solid cancer data of the A-bomb survivors.

Risk estimates for radiation-induced cancer are primarily based on the follow-up of the Japanese A-bomb survivors. Their exposures were due to gamma rays and neutrons, and, currently--with the assumed low RBE = 10 of neutrons and reference to the colon dose--the late radiation effects are almost fully attributed to the gamma rays. Solid cancer risk estimates for different organ sites are assessed here, and an inconspicuous but statistically highly significant trend of larger values is found for the organs closer to the body surface; i.

The inverse dose-rate effect for radon induced lung cancer: a modified approach for risk modelling.

One of the features of high LET alpha-ray exposure due to radon inhalation is the well-known inverse dose-rate effect. The longer a given dose is delivered to the lung, the higher is its carcinogenic effect. This introduces the problem of risk extrapolation from high levels of radon exposure typical for uranium miners, down to low levels of radon exposure typical for the general population.

Are all photon radiations similar in large absorbers?--a comparison of electron spectra.

Conventional X rays, i.e. X rays generating voltage between roughly 150 and 300 kV, are used in many radio-diagnostic procedures and also in radiobiological experiments.

Cancer risk estimates for gamma-rays with regard to organ-specific doses Part II: site-specific solid cancers.

Part I of this study presented an analysis of the solid cancer mortality data for 1950-1997 from the Japanese life-span study of the A-bomb survivors to assess the cancer risk for gamma-rays in terms of the organ-specific dose for all solid cancers combined. Compared to earlier analyses, considerably more curvature in the dose-effect relation is indicated by these computations, which now suggests a dose and dose-rate effectiveness factor of about 2. The computations are extended here in order to explore the site-specific solid cancer risks for various organs.

Weighting factors for radiation quality: how to unite the two current concepts.

The quality factor, Q(L), used to be the universal weighting factor to account for radiation quality, until--in its 1991 Recommendations--the ICRP established a dichotomy between 'computable' and 'measurable' quantities. The new concept of the radiation weighting factor, w(R), was introduced for use with the 'computable' quantities, such as the effective dose, E. At the same time, the application of Q(L) was restricted to 'measurable' quantities, such as the operational quantities ambient dose equivalent or personal dose equivalent.

Cancer risk estimates for gamma-rays with regard to organ-specific doses. Part I: All solid cancers combined.

A previous analysis of the solid cancer mortality data for 1950-1990 from the Japanese life-span study of the A-bomb survivors has assessed the solid cancer risk coefficients for gamma-rays in terms of the low dose risk coefficient ERR/Gy, i.e. the initial slope of the ERR vs.

Options for the modified radiation weighting factor of neutrons.

The recent ICRP Report 92 has noted that the current radiation weighting factor, wR, depends on the energy of the incident neutrons in a manner that differs substantially from the dependence, which results from the current convention, QL. At all neutron energies, but most conspicuously below 1 MeV, the values of wR exceed those of the effective quality factor, qE. The discrepancy is largely due to the fact that--in the absence of computed values of the effective quality factor for neutrons--wR has been patterned after the values of the ambient quality factor, which accounts insufficiently for the low-linear energy transfer (LET) gamma ray component from neutron capture in the human body.

Comparative microdosimetry of photoelectrons and Compton electrons: an analysis in terms of generalized proximity functions.

A current discussion on mammography screening is focused on claims of high relative biological effectiveness (RBE) of mammography X rays compared to conventional 200 kV X rays. An earlier assessment in terms of the electron spectra of these radiations has led to the conclusion that the RBE is bound to be less than 2, regardless of specific model assumptions and the microdosimetric properties of electrons. The present study extends this result in terms of the microdosimetric proximity function, t(x), for electrons, which is essentially the spatial auto-correlation function of energy within particle tracks.

Lung cancer mortality among nuclear workers of the Mayak facilities in the former Soviet Union. An updated analysis considering smoking as the main confounding factor.

A new analysis of lung cancer mortality in a cohort of male Mayak workers who started their employment in the plutonium and reprocessing plants between 1948 and 1958 has been carried out in terms of a relative risk model. The follow-up has been extended until 1999, moreover a new dosimetry system (DOSES2000) has been established. Particular emphasis has been given to a discrimination of the effects of external gamma-exposure and internal alpha-exposure due to incorporated plutonium.

Error bands for the linear-quadratic dose-effect relation.

Least square or maximum likelihood fits to the linear-quadratic dose-effect relation are common in experimental radiobiology and in radio-epidemiology. The fit procedure provides the estimates of the linear and the quadratic dose coefficients, a and b, as well as their standard errors, s(a) and s(b). The magnitude of the standard errors s(a) and s(b) is partly determined by the fact that-for a given data set-different parameter combinations (a, b) can produce rather similar fits, i.

Choice of model and uncertainties of the gamma-ray and neutron dosimetry in relation to the chromosome aberrations data in Hiroshima and Nagasaki.

Chromosome data pertaining to blood samples from 1,703 survivors of the Hiroshima and Nagasaki A-bombs, were utilized and different models for chromosome aberration dose response investigated. Models applied included those linear or linear-quadratic in equivalent dose. Models in which neutron and gamma doses were treated separately (LQ-L model) were also used, which included either the use of a low-dose limiting value for the relative biological effectiveness (RBE) of neutrons of R(0)=70+/-10 or an RBE value of R(1)=15+/-5 at 1 Gy.

The Southern Urals radiation studies. A reappraisal of the current status.

In the late 1940s and early 1950s the nuclear workers of the Mayak Production Association in the Southern Urals were exposed to high doses from gamma-rays and from incorporated plutonium. In addition, the population of the Techa riverside downstream of the plutonium-production sites received continued exposures from external gamma-rays due to fission products released into the river and from the internal radiation due to incorporation of the fission products. Based on two international coordination meetings in 1998 and 2000, a synopsis has been given recently in this journal of the radioepidemiological studies on these exposed populations.

Differential mutation frequency in mitochondrial DNA from thyroid tumours.

Lack of a chromatin structure and histone protection makes mitochondrial DNA susceptible to oxidative damage. Suboptimal DNA repair leads to a higher frequency of mitochondrial mutations, which are associated with aging, carcinogenesis and environmental insult. The instability of the hypervariable region II of the mitochondrial genome was investigated in radiation-associated thyroid tumours, which were diagnosed in children from Belarus after the accident at the Chernobyl nuclear power plant, and from 40 sporadic thyroid tumours from Munich.