Nociceptor inputs can trigger a prolonged but reversible increase in the excitability and synaptic efficacy of neurons in central nociceptive pathways, the phenomenon of central sensitization. Central sensitization manifests as pain hypersensitivity, particularly dynamic tactile allodynia, secondary punctate or pressure hyperalgesia, aftersensations, and enhanced temporal summation. It can be readily and rapidly elicited in human volunteers by diverse experimental noxious conditioning stimuli to skin, muscles or viscera, and in addition to producing pain hypersensitivity, results in secondary changes in brain activity that can be detected by electrophysiological or imaging techniques. Studies in clinical cohorts reveal changes in pain sensitivity that have been interpreted as revealing an important contribution of central sensitization to the pain phenotype in patients with fibromyalgia, osteoarthritis, musculoskeletal disorders with generalized pain hypersensitivity, headache, temporomandibular joint disorders, dental pain, neuropathic pain, visceral pain hypersensitivity disorders and post-surgical pain. The comorbidity of those pain hypersensitivity syndromes that present in the absence of inflammation or a neural lesion, their similar pattern of clinical presentation and response to centrally acting analgesics, may reflect a commonality of central sensitization to their pathophysiology. An important question that still needs to be determined is whether there are individuals with a higher inherited propensity for developing central sensitization than others, and if so, whether this conveys an increased risk in both developing conditions with pain hypersensitivity, and their chronification. Diagnostic criteria to establish the presence of central sensitization in patients will greatly assist the phenotyping of patients for choosing treatments that produce analgesia by normalizing hyperexcitable central neural activity. We have certainly come a long way since the first discovery of activity-dependent synaptic plasticity in the spinal cord and the revelation that it occurs and produces pain hypersensitivity in patients. Nevertheless, discovering the genetic and environmental contributors to and objective biomarkers of central sensitization will be highly beneficial, as will additional treatment options to prevent or reduce this prevalent and promiscuous form of pain plasticity.

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Central sensitization: implications for the diagnosis and treatment of pain.

The role of atmospheric dispersion in the seasonal variation of PM1 and PM2.5 concentration and composition in the urban area of Milan (Italy)

Long period study of outdoor radon concentration in Milan and correlation between its temporal variations and dispersion properties of atmosphere

https://www.ge.infn.it/~prati/Fisica%20Nucleare%20Applicata/articoli/valli,%20vecchi.pdf

A study on nighttime–daytime PM10 concentration and elemental composition in relation to atmospheric dispersion in the urban area of Milan (Italy)

Characterisation of the traffic sources of PM through size-segregated sampling, sequential leaching and ICP analysis

Atmospheric 222 Rn concentration was measured at ground level in Milan. The measurements were obtained using two different methods: a high-volume alpha particle detector giving a direct measurement of 222 Rn concentration, and the alpha activity released by radon progeny measured through the collection of atmospheric particulate. From the behaviour of the concentrations of this radioactive tracer it was possible to get data on the structure of the Planetary Boundary Layer. The changes in daily and weekly atmospheric radon levels are related to the stability or turbulence of the low troposphere. In particular, the analysis of data from sunny windless days indicates growth and dissolution of the inversion layer. Radon data can be used as the basis for the development of pollutant diffusion models and, in particular, could provide support to studies on ozone concentration in the Planetary Boundary Layer.

222Radon as a Tracer of Atmospheric Motions: A Study in Milan

222Rn as indicator of atmospheric turbulence: measurements at Lake Maggiore and on the pre-Alps.

This paper reports and discusses the behaviour of radon concentration with time in an uninhabited dwelling. The relationship between variations in radon concentrations and indoor-outdoor temperatures and wind intensity has also been discussed. Radon concentration was measured hourly in a house located at a height of 800 m in the Lombard Prealps, at the top of the Valassina valley. The wind velocity and indoor-outdoor temperatures were measured by means of a meteorological station located on the terrace of the house. The data were analysed using the LBL model for indoor-outdoor air exchange and the models for the indoor accumulation of radon due to exhalation from building materials and pressure-driven infiltrations located underground. The role of wind and indoor-outdoor temperatures were analysed. The agreement of measurements with modelling clearly demonstrates the importance of the different sources of indoor radon. As the investigation was conducted in an uninhabited house, the measurements were not affected by the behaviour of people, e.g. opening and closing of windows. Measurements of the outdoor atmospheric concentrations of 2 2 2 Rn provide an index of the atmospheric stability, the formation of thermal inversions and convective turbulence.

L. Sesana

Papers

Long period study of outdoor radon concentration in Milan and correlation between its temporal variations and dispersion properties of atmosphere

222Radon as a Tracer of Atmospheric Motions: A Study in Milan

222Rn as indicator of atmospheric turbulence: measurements at Lake Maggiore and on the pre-Alps.

Hourly indoor radon measurements in a research house.

Radon-prone areas in the Lombard plain.