Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 10 de 10
Filtrar
1.
Artículo en Inglés | MEDLINE | ID: mdl-34682417

RESUMEN

In 2016 the Directive 2013/35/EU regarding the protection of health and safety of workers exposed to electromagnetic fields was transposed in Italy. Since then, the authors of this paper have been faced with several issues related to the implementation of the provisions of the Directive, which pose some interpretative and operative concerns. A primary critical feature of the Directive is that, in some circumstances, conditions of "overexposure", i.e., of exceeding the exposure limits, are allowed. In the case of transient effects, the "flexibility" concerning the compliance with exposure limits is based on the approach introduced by ICNIRP in its guidelines on static magnetic fields and on time-varying electric and magnetic fields. On the contrary, the possibility of exceeding the exposure limits for health effects, formally recognized in the article of the Directive dealing with derogations, is not included in the ICNIRP guidelines. This paper analyzes the main concerns in interpreting and managing some provisions of the Directive with particular reference to the issue of how the employer can manage the situations of overexposure.


Asunto(s)
Campos Electromagnéticos , Exposición Profesional , Campos Electromagnéticos/efectos adversos , Humanos , Italia
2.
Med Phys ; 44(11): 5988-5996, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-28857189

RESUMEN

PURPOSE: The exposure of operators moving in the static field of magnetic resonance (MR) facilities was assessed through measurements of the magnetic flux density, which is experienced as variable in time because of the movement. Collected data were processed to allow the comparison with most recent and authoritative safety standards. METHODS: Measurements of the experienced magnetic flux density B were performed using a probe worn by volunteers moving in MR environments. A total of 55 datasets were acquired nearby a 1.5 T, 3 T, and 7 T whole body scanners. Three different metrics were applied: the maximum intensity of B, to be compared with 2013/35/EU Directive exposure limit values for static fields; the maximum variation of the vector B on every 3s-interval, for comparison with the ICNIRP-2014 basic restriction aimed at preventing vertigo effects; two weighted-peak indices (for "sensory" and "health" effects: SENS-WP, HLTH-WP), assessing compliance with ICNIRP-2014 and EU Directive recommendations intended to prevent stimulation effects. RESULTS: Peak values of |B| were greater than 2 T in nine of the 55 datasets. All the datasets at 1.5 T and 3 T were compliant with the limit for vertigo effects, whereas six datasets at 7 T turned out to be noncompliant. At 7 T, all 36 datasets were noncompliant for the SENS-WP index and 26 datasets even for the HLTH-WP one. CONCLUSIONS: Results demonstrate that compliance with EU Directive limits for static fields does not guarantee compliance with ICNIRP-2014 reference levels and clearly show that movements in the static field could be the key component of the occupational exposure to EMF in MR facilities.


Asunto(s)
Campos Magnéticos , Imagen por Resonancia Magnética/instrumentación , Movimiento (Física) , Exposición Profesional/análisis , Humanos , Reproducibilidad de los Resultados
3.
J Magn Reson ; 180(2): 222-8, 2006 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-16554181

RESUMEN

The revisited version of the HACACO experiment here presented, is more robust and straightforward to implement and continues to be, to a greater extent, a convenient tool for protein backbone resonance assignment. Additionally, it turns out to be a sensitive and accurate method to measure C(alpha)-H(alpha) residual dipolar couplings (RDCs). The performance of our new pulse scheme for measurement of RDCs was tested on two proteins with different secondary structures: one characterized by a high beta-sheet content, the second dominated by the presence of alpha-helices. In both examples the new method provided significantly more accurate data, compared to all previously published 3D techniques.


Asunto(s)
Proteínas Bacterianas/química , Resonancia Magnética Nuclear Biomolecular/métodos , Isótopos de Carbono , Conformación Proteica
4.
Ann Ist Super Sanita ; 52(3): 386-396, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27698297

RESUMEN

The accident at Tokyo Electric Power Company's (TEPCO's) Fukushima Daiichi nuclear power plant (NPP) has been one of the dominant topic in nuclear safety and it has brought new attention on the matter of accidents in NPPs due to external events related to natural causes. Climate change has risen new risks and the growing probability of extreme external events has increased exposure and vulnerability of workers in the nuclear sector. However extreme natural events are a threat not only to NPPs but to all facilities dealing with radioactive material and in an emergency scenario they can affect the effectiveness and implementation of safety devices and procedures and also prevent communications, causing delays in the readiness of response. It is clear that adaptation strategies are necessary to cope with emerging changes in climate and a new nuclear safety culture is growing, that addresses accidents initiated not only by internal but also by external events.


Asunto(s)
Cambio Climático , Exposición Profesional/estadística & datos numéricos , Salud Laboral/estadística & datos numéricos , Radiación Ionizante , Humanos , Plantas de Energía Nuclear , Monitoreo de Radiación , Protección Radiológica , Liberación de Radiactividad Peligrosa
5.
Ann Ist Super Sanita ; 52(3): 325-337, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27698291

RESUMEN

Observed changes at the global scale. An increase of the annual mean global temperature and changes of other climate parameters have been observed in the last century. The global temperature and the atmospheric concentration of greenhouse gases are changing at a very fast pace compared to those found in palaeoclimate records. Changes in the Mediterranean. Variations of some climate change indicators can be much larger at the local than at the global scale, and the Mediterranean has been indicated among the regions most sensitive to climate change, also due to the increasing anthropogenic pressure. Model projections for the Mediterranean foresee further warming, droughts, and long-lasting modifications. IMPACTS: Regional climate changes impact health and ecosystems, creating new risks, determined not only by weather events, but also by changing exposures and vulnerabilities. These issues, and in particular those regarding occupational safety, have not been sufficiently addressed to date.


Asunto(s)
Cambio Climático , Efecto Invernadero , Humanos , Región Mediterránea , Salud Laboral/tendencias
6.
FEBS Lett ; 548(1-3): 11-6, 2003 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-12885399

RESUMEN

The interactions of calcium-calmodulin with two fragments of the N-terminal domains of the olfactory alpha-subunit and rod beta-subunit cyclic nucleotide-gated channels have been investigated using nuclear magnetic resonance spectroscopy. The results indicate that in the two cases both the N-terminal and the C-terminal calmodulin lobes are involved in the interaction. The olfactory cyclic nucleotide-gated channel segment forms a 1:1 complex with calmodulin, whereas the rod fragment forms a 2:1 complex. The correlation times of the two complexes, as estimated by (15)N relaxation studies, are compatible with the observed stoichiometries. These results indicate differences in the mode of action by which calmodulin modulates the activity of both channels, and suggest either that the rod channel is modulated through a simultaneous interaction of two beta-subunits with calmodulin or that other regions of the N-terminus are necessarily implicated in the binding.


Asunto(s)
Calcio/metabolismo , Calmodulina/metabolismo , Canales Iónicos/metabolismo , Secuencia de Aminoácidos , Animales , Sitios de Unión , Calcio/química , Calmodulina/química , Canales Catiónicos Regulados por Nucleótidos Cíclicos , Canales Iónicos/química , Resonancia Magnética Nuclear Biomolecular/métodos , Bulbo Olfatorio/química , Unión Proteica , Subunidades de Proteína , Células Fotorreceptoras Retinianas Bastones/química , Xenopus
7.
Int J Occup Med Environ Health ; 25(1): 97-102, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22219062

RESUMEN

The paper describes the cases of 3 female health operators with implanted copper IUDs, developing menometrorrhagia some months after an increase of the working time in a Magnetic Resonance Imaging (MRI) Unit (1.5 T), that progressively disappeared when the previous organization, involving discontinuous work shifts at MRI, was re-established. No known factors possibly related to menometrorrhagia were evidenced in the 3 operators, supporting the hypothesis of a role of the exposure to the electromagnetic fields (EMF) induced by the MRI system in symptoms induction. The possible mechanism remains unsettled, but menometrorrhagia might be triggered by a phlogistic stimulus caused by EMF, possibly the low-frequency currents induced in the wires of the IUD during the movements of the operator inside the static magnetic field generated by the MRI permanent magnet. Until now, the problem of possible interactions between copper IUDs and EMF induced by MRI has been considered in patients undergoing imaging, but the possible risk in MRI Units operators has been largely neglected. To our knowledge, the occurrence of menometrorrhagia is not routinely checked in health surveillance of MRI operators, so these symptoms can pass unnoticed, especially if they are transitory. Therefore, underreporting is rather possible. The cases described here support the need for further research on this topic, especially considering the progressive diffusion of more powerful MRI scanners (3 T and more), and of the interventional magnetic resonance imaging, both potentially involving higher EMF exposures, and a large number of MRI female operators, possibly using IUDs. The possibility that MRI operators with implanted metallic IUDs can be included in the group of "workers at particular risk" according to the EU Directive 2004/40/EC should be considered.


Asunto(s)
Dispositivos Intrauterinos de Cobre , Dispositivos Intrauterinos , Imagen por Resonancia Magnética , Menorragia/etiología , Exposición Profesional/efectos adversos , Adulto , Campos Electromagnéticos/efectos adversos , Femenino , Humanos , Italia , Menorragia/fisiopatología , Adulto Joven
8.
J Expo Sci Environ Epidemiol ; 21(6): 634-45, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21468121

RESUMEN

An inaccurate evaluation of exposure is considered a possible cause for the inadequate conclusiveness of epidemiological research on adverse effects of extremely low frequency-magnetic fields (ELF-MF). The objective of this study is to provide an evaluation of current ELF-MF exposure in workers, the specific contribution of occupational exposure to overall 24-h exposure, and the representativeness of a job exposure matrix (JEM). ELF-MF exposure was monitored in 543 workers for 2 days using personal meters. Time-weighted average (TWA) levels at work, at home and outside the home were calculated. A JEM based on the 1988 International Standard Classification of Occupations (ISCO 88) was created. Median exposure at work, at home and outside the home were 0.14, 0.03 and 0.05 µT, respectively. Occupational exposure accounted for about 60% of 24-h exposure. In the JEM, about 50% of the classified occupations included significantly different individual TWAs. Occupational exposure to ELF-MF appeared low. Median exposure levels at home and outside were 20-28% of the occupational level, giving a minor contribution to overall day-to-day exposure. The frequent occurrence of workers with different TWA included under the same job title highlights the risk of misclassification in epidemiological studies on ELF-MF effects based on JEM.


Asunto(s)
Campos Electromagnéticos , Exposición Profesional/análisis , Adolescente , Adulto , Femenino , Humanos , Italia/epidemiología , Masculino , Persona de Mediana Edad , Exposición Profesional/clasificación , Exposición Profesional/estadística & datos numéricos , Factores de Riesgo , Factores de Tiempo , Adulto Joven
9.
J Biol Chem ; 282(1): 667-79, 2007 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-17074768

RESUMEN

Calmodulin, regulatory, and essential myosin light chain are evolutionary conserved proteins that, by binding to IQ motifs of target proteins, regulate essential intracellular processes among which are efficiency of secretory vesicles release at synapsis, intracellular signaling, and regulation of cell division. The yeast Saccharomyces cerevisiae calmodulin Cmd1 and the essential myosin light chain Mlc1p share the ability to interact with the class V myosin Myo2p and Myo4 and the class II myosin Myo1p. These myosins are required for vesicle, organelle, and mRNA transport, spindle orientation, and cytokinesis. We have used the budding yeast model system to study how calmodulin and essential myosin light chain selectively regulate class V myosin function. NMR structural analysis of uncomplexed Mlc1p and interaction studies with the first three IQ motifs of Myo2p show that the structural similarities between Mlc1p and the other members of the EF-hand superfamily of calmodulin-like proteins are mainly restricted to the C-lobe of these proteins. The N-lobe of Mlc1p presents a significantly compact and stable structure that is maintained both in the free and complexed states. The Mlc1p N-lobe interacts with the IQ motif in a manner that is regulated both by the IQ motifs sequence as well as by light chain structural features. These characteristic allows a distinctive interaction of Mlc1p with the first IQ motif of Myo2p when compared with calmodulin. This finding gives us a novel view of how calmodulin and essential light chain, through a differential binding to IQ1 of class V myosin motor, regulate this activity during vegetative growth and cytokinesis.


Asunto(s)
Cadenas Pesadas de Miosina/química , Cadenas Ligeras de Miosina/química , Miosina Tipo V/química , Proteínas de Saccharomyces cerevisiae/química , Secuencias de Aminoácidos , Secuencia de Aminoácidos , Calmodulina/química , División Celular , Clonación Molecular , Espectroscopía de Resonancia Magnética , Modelos Moleculares , Datos de Secuencia Molecular , Cadenas Ligeras de Miosina/metabolismo , Miosinas/química , Unión Proteica , Conformación Proteica , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo
10.
J Biomol NMR ; 31(3): 185-99, 2005 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-15803393

RESUMEN

The NMR high-resolution structure of calmodulin complexed with a fragment of the olfactory cyclic-nucleotide gated channel is described. This structure shows features that are unique for this complex, including an active role of the linker connecting the N- and C-lobes of calmodulin upon binding of the peptide. Such linker is not only involved in the formation of an hydrophobic pocket to accommodate a bulky peptide residue, but it also provides a positively charged region complementary to a negative charge of the target. This complex of calmodulin with a target not belonging to the kinase family was used to test the residual dipolar coupling (RDC) approach for the determination of calmodulin binding modes to peptides. Although the complex here characterized belongs to the (1--14) family, high Q values were obtained with all the 1:1 complexes for which crystalline structures are available. Reduction of the RDC data set used for the correlation analysis to structured regions of the complex allowed a clear identification of the binding mode. Excluded regions comprise calcium binding loops and loops connecting the EF-hand motifs.


Asunto(s)
Calmodulina/química , Calmodulina/metabolismo , Canales Iónicos/metabolismo , Fragmentos de Péptidos/metabolismo , Proteínas Quinasas/metabolismo , Secuencias de Aminoácidos , Secuencia de Aminoácidos , Aminoácidos Acídicos/química , Aminoácidos Aromáticos/química , Aminoácidos Básicos/química , Animales , Sitios de Unión , Calmodulina/genética , Canales Catiónicos Regulados por Nucleótidos Cíclicos , Enlace de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Canales Iónicos/química , Modelos Químicos , Modelos Moleculares , Datos de Secuencia Molecular , Radioisótopos de Nitrógeno , Resonancia Magnética Nuclear Biomolecular , Bulbo Olfatorio/química , Fragmentos de Péptidos/química , Unión Proteica , Conformación Proteica , Estructura Secundaria de Proteína , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/metabolismo , Reproducibilidad de los Resultados , Homología de Secuencia de Aminoácido , Espectrometría Raman , Xenopus laevis
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA