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2.
SAR QSAR Environ Res ; 29(8): 591-611, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30052064

RESUMO

Results from the Ames test are the first outcome considered to assess the possible mutagenicity of substances. Many QSAR models and structural alerts are available to predict this endpoint. From a regulatory point of view, the recommendation from international authorities is to consider the predictions of more than one model and to combine results in order to develop conclusions about the mutagenicity risk posed by chemicals. However, the results of those models are often conflicting, and the existing inconsistency in the predictions requires intelligent strategies to integrate them. In our study, we evaluated different strategies for combining results of models for Ames mutagenicity, starting from a set of 10 diverse individual models, each built on a dataset of around 6000 compounds. The novelty of our study is that we collected a much larger set of about 18,000 compounds and used the new data to build a family of integrated models. These integrations used probabilistic approaches, decision theory, machine learning, and voting strategies in the integration scheme. Results are discussed considering balanced or conservative perspectives, regarding the possible uses for different purposes, including screening of large collection of substances for prioritization.


Assuntos
Modelos Moleculares , Testes de Mutagenicidade , Relação Estrutura-Atividade , Simulação por Computador , Relação Quantitativa Estrutura-Atividade
4.
Phys Rev Lett ; 117(17): 179902, 2016 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-27824452

RESUMO

This corrects the article DOI: 10.1103/PhysRevLett.116.112502.

5.
Artigo em Inglês | MEDLINE | ID: mdl-27692294

RESUMO

Good cell culture practice and characterization of the cell lines used are of critical importance in in vitro genotoxicity testing. The objective of this initiative was to make continuously available stocks of the characterized isolates of the most frequently used mammalian cell lines in genotoxicity testing anywhere in the world ('IVGT' cell lines). This project was organized under the auspices of the International Life Sciences Institute (ILSI) Health and Environmental Sciences Institute (HESI) Project Committee on the Relevance and Follow-up of Positive Results in In Vitro Genetic Toxicity (IVGT) Testing. First, cell isolates were identified that are as close as possible to the isolate described in the initial publications reporting their use in genotoxicity testing. The depositors of these cell lines managed their characterization and their expansion for preparing continuously available stocks of these cells that are stored at the European Collection of Cell Cultures (ECACC, UK) and the Japanese Collection of Research Bioresources (JCRB, Japan). This publication describes how the four 'IVGT' cell lines, i.e. L5178Y TK+/- 3.7.2C, TK6, CHO-WBL and CHL/IU, were prepared for deposit at the ECACC and JCRB cell banks. Recommendations for handling these cell lines and monitoring their characteristics are also described. The growth characteristics of these cell lines (growth rates and cell cycles), their identity (karyotypes and genetic status) and ranges of background frequencies of select endpoints are also reported to help in the routine practice of genotoxicity testing using these cell lines.


Assuntos
Técnicas de Cultura de Células/normas , Dano ao DNA/efeitos dos fármacos , Linfócitos/efeitos dos fármacos , Linfoma/tratamento farmacológico , Testes de Mutagenicidade/normas , Mutagênicos/toxicidade , Padrões de Referência , Animais , Células CHO , Células Cultivadas , Cricetulus , Relação Dose-Resposta a Droga , Humanos , Linfócitos/citologia , Linfócitos/metabolismo , Linfoma/metabolismo , Linfoma/patologia , Camundongos , Cariotipagem Espectral , Proteína Supressora de Tumor p53/metabolismo
6.
SAR QSAR Environ Res ; 27(5): 371-84, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27167159

RESUMO

A round-robin exercise was conducted within the CALEIDOS LIFE project. The participants were invited to assess the hazard posed by a substance, applying in silico methods and read-across approaches. The exercise was based on three endpoints: mutagenicity, bioconcentration factor and fish acute toxicity. Nine chemicals were assigned for each endpoint and the participants were invited to complete a specific questionnaire communicating their conclusions. The interesting aspect of this exercise is the justification behind the answers more than the final prediction in itself. Which tools were used? How did the approach selected affect the final answer?


Assuntos
Substâncias Perigosas/toxicidade , Medição de Risco/métodos , Animais , Simulação por Computador , Peixes , Humanos , Testes de Mutagenicidade , Relação Quantitativa Estrutura-Atividade , Reprodutibilidade dos Testes , Software , Inquéritos e Questionários , Testes de Toxicidade Aguda , Incerteza
7.
Phys Rev Lett ; 116(11): 112502, 2016 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-27035297

RESUMO

We present the nuclear matrix element for the neutrinoless double-beta decay of ^{48}Ca based on large-scale shell-model calculations including two harmonic oscillator shells (sd and pf shells). The excitation spectra of ^{48}Ca and ^{48}Ti, and the two-neutrino double-beta decay of ^{48}Ca are reproduced in good agreement to the experimental data. We find that the neutrinoless double-beta decay nuclear matrix element is enhanced by about 30% compared to pf-shell calculations. This reduces the decay lifetime by almost a factor of 2. The matrix-element increase is mostly due to pairing correlations associated with cross-shell sd-pf excitations. We also investigate possible implications for heavier neutrinoless double-beta decay candidates.

8.
Nature ; 530(7591): 453-6, 2016 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-26911781

RESUMO

In recent years, millisecond-duration radio signals originating in distant galaxies appear to have been discovered in the so-called fast radio bursts. These signals are dispersed according to a precise physical law and this dispersion is a key observable quantity, which, in tandem with a redshift measurement, can be used for fundamental physical investigations. Every fast radio burst has a dispersion measurement, but none before now have had a redshift measurement, because of the difficulty in pinpointing their celestial coordinates. Here we report the discovery of a fast radio burst and the identification of a fading radio transient lasting ~6 days after the event, which we use to identify the host galaxy; we measure the galaxy's redshift to be z = 0.492 ± 0.008. The dispersion measure and redshift, in combination, provide a direct measurement of the cosmic density of ionized baryons in the intergalactic medium of ΩIGM = 4.9 ± 1.3 per cent, in agreement with the expectation from the Wilkinson Microwave Anisotropy Probe, and including all of the so-called 'missing baryons'. The ~6-day radio transient is largely consistent with the radio afterglow of a short γ-ray burst, and its existence and timescale do not support progenitor models such as giant pulses from pulsars, and supernovae. This contrasts with the interpretation of another recently discovered fast radio burst, suggesting that there are at least two classes of bursts.

9.
J Eur Acad Dermatol Venereol ; 30(8): 1379-83, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26446433

RESUMO

BACKGROUND: Hypohidrosis/anhidrosis are congenital or acquired sweating impairments. Among them, acquired idiopathic generalized anhidrosis/hypohidrosis (AIGA) is the most common, and characterized by favourable response to systemic corticosteroid, however, no clinical markers for disease severity or activity have been developed. OBJECTIVE: Our aim was to verify the usefulness of serum carcinoembryonic antigen (CEA) level monitoring as a clinical marker for disease activity of AIGA. METHODS: Ten cases of AIGA diagnosed at Asahikawa Medical University, from 1980 to 2014 were included in the study. CEA and/or CEACAM1 expression level was analysed using immunohistochemistry and enzyme-linked immunosorbent assay. RESULT: CEA expression was restricted to the apical membrane of glandular cells in eccrine sweat glands in most of the three types of cases we examined [healthy control, patients with atopic dermatitis (AD) or urticaria]. However, CEA expression was detected diffusely and much more intensively in eight of the 10 AIGA cases included in this study. CEACAM1-expression was much more restricted on the apical membrane of glandular cells of both the AIGA cases and the other control subjects. While serum CEA levels increased in all five AIGA cases examined (5.8-43.2 ng/mL), it remained within normal limits in all control subjects: nine healthy individuals; 10 cases of AD; 10 cases of idiopathic urticaria; four cases of normohidrotic cholinergic urticaria (Mann-Whitney's U-test, P < 0.05). The increased serum CEA levels in AIGA decreased in conjunction with improved sweating during methyl prednisolone pulse therapy or repeated bathing. CONCLUSION: Serum CEA level may serve as a clinical marker for AIGA activity.


Assuntos
Biomarcadores/sangue , Antígeno Carcinoembrionário/sangue , Hipo-Hidrose/diagnóstico , Adolescente , Adulto , Idoso , Estudos de Casos e Controles , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Hipo-Hidrose/sangue , Hipo-Hidrose/imunologia , Masculino , Pessoa de Meia-Idade , Adulto Jovem
10.
Phys Rev Lett ; 112(11): 112502, 2014 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-24702355

RESUMO

Gamow-Teller (GT) transitions in atomic nuclei are sensitive to both nuclear shell structure and effective residual interactions. The nuclear GT excitations were studied for the mass number A = 42, 46, 50, and 54 "f-shell" nuclei in ((3)He, t) charge-exchange reactions. In the (42)Ca → (42)Sc reaction, most of the GT strength is concentrated in the lowest excited state at 0.6 MeV, suggesting the existence of a low-energy GT phonon excitation. As A increases, a high-energy GT phonon excitation develops in the 6-11 MeV region. In the (54)Fe → (54)Co reaction, the high-energy GT phonon excitation mainly carries the GT strength. The existence of these two GT phonon excitations are attributed to the 2 fermionic degrees of freedom in nuclei.

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