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Compensation for occupational pulmonary diseases requires the establishment of guidelines based on standardized and objective criteria, in order to provide compensation that is as fair as possible to patients who suffer from them. A review of the elements necessary for the examination of an individual file was carried out by a working group. It is accepted that respiratory functional exploration is the key element in assessing the level of permanent disability in all of these conditions, with the exception of thoracic malignancies. Guiding scales have been developed for the respiratory impairment of three types of conditions: occupational asthma, thoracic malignancy, and other respiratory diseases. Additional criteria for increasing the permanent disability level are also proposed in order to take into account professional prejudice, in particular the possibility or not of continuing the occupational activity, in the same job or after changing to another. For certain respiratory diseases, a periodic reassessment of the initially attributed permanent disability level is recommended as well as the initial one at the time of definitive cessation of occupational activity.

Resume Les etiologies des syndromes cavitaires pulmonaires sont multiples, notamment neoplasiques, infectieuses ou inflammatoires. Une etiologie particuliere est celle d’infarctus pulmonaires multiples secondaires a des embolies pulmonaires. Ce diagnostic peut etre suspecte devant la localisation sous-pleurale des lesions et l’association avec un thrombus arteriel pulmonaire. Nous rapportons le cas d’une patiente atteinte d’une hypertension pulmonaire post-embolique (HTP PE) chronique associee a une thrombophilie familiale revelee par des infarctus pulmonaires excaves. L’HTP PE chronique est parfois diagnostiquee lors d’une recidive embolique sur des lesions anciennes passees inapercues. Parmi les conditions medicales associees au developpement d’une HTP PE, figurent certaines thrombophilies telles que l’elevation isolee du facteur VIII.

In this article a French working party critically review the international literature to revise the definition, pathophysiology, treatment and cost of exacerbations of adult asthma. The various guidelines do not always provide a consistent definition of exacerbations of asthma. An exacerbation can be defined as deterioration of clinical and/or functional parameters lasting more than 24 hours, without return to baseline, requiring a change of treatment. No single clinical or functional criterion can be used as an early marker of an exacerbation. Innate and acquired immune mechanisms, modified by contact with infectious, irritant or allergenic agents, participate in the pathogenesis of exacerbations, which are accompanied by bronchial inflammation. In 2010, mortality is related to progression of exacerbations, often occurring before the patient seeks medical attention. The objective of treatment is to control asthma and prevent exacerbations. However, many factors can trigger exacerbations and often cannot be controlled. The efficacy of inhaled corticosteroids has been demonstrated on reduction of the number of exacerbations and the number of asthma-related deaths. This treatment is cost-effective, especially in terms of reduction of exacerbations.

A computerized model of steady–state photon diffusion within turbid media such as biological tissues, solved by means of the Finite Element Method (FEM) is presented in this paper. Assuming that the different media are illuminated by a flat collimated laser beam source, we develop the basic theory including the suitable boundary conditions along the meshed domain. Model simulations depict firstly photon-flux density patterns in the $r-z$ plane associated with axis fluence rate profiles, plotted as functions of media properties and beam sizes. A second objective was to display both the rate of re-emitted optical power integrated by an optical fibre radially displaced away from the source and the power integrated by an optical fibre axially moved inside the tissue. Simulation studies are further extended to multilayered media such as skin and aorta, in order to describe the light propagation through these tissue structures more realistically.

Many studies have been carried out on reactive hyperaemia parameters in laser Doppler flowmetry (LDF) analysis. For the diagnosis of peripheral arterial occlusive diseases, the most important parameters are the time to peak flow (tpLDF) and the peak flow value (pLDF). However, the determination of these parameters is very often subjective due to the presence of marked oscillations on LDF signals. The present work shows that the de-noising of the concentration of m oving b lood c ell signals (CMBC) can be of great interest in determining new reliable reactive hyperaemia parameters (tpCMBC and pCMBC). 40 CMBC signals recorded on 10 healthy subjects and on 10 patients with peripheral arterial occlusive diseases are thus smoothed using wavelets. For a 1 min occlusion, the parameters computed are tpCMBC healthy = 20.9 s, pCMBC healthy = 40.3 arbitrary units (a.u.), tpCMBC patient = 31.2 S, pCMBC patients = 31.5 a.u. After 2 min of occlusion, tpCMBC healthy = 28.7 s, pCMBC healthy = 61.0 a.u., tpCMBC patient = 38.8 s, pCMBC patient = 41.7 a.u. The 2 new parameters, tpCMBC and pCMBC, are computed on de-noised signals. Therefore, they can improve the diagnosis of peripheral arterial occlusive diseases.

Experimental results of surface melting by pulsed Nd-YAG laser irradiation of titanium covered with graphite powder were analysed in comparison with the results of numerical simulations. The simulations of the thermal events, such as the maximum of temperature gradient at the surface and the duration of the liquid state after irradiation, were found due to a semi-analytic model of the space-time temperature distributions which were induced by the irradiation treatments. These simulations were required in order to calculate a series of integrals by Simpson's numerical method. They have allowed us to explain the experimental results such as the incorporation of carbon in melted zone, which produces titanium carbide and possible graphite inclusions, as a function of the irradiation parameters. The perpetual absence in the thickness and the exceptional presence at the surface of the solidification structure resulting from the plane-front growth of titanium carbide have, moreover, been justified.

Laser Doppler flowmetry (LDF) is a noninvasive method to monitor skin perfusion and is very useful in studying reactive hyperemia signals. For this latter case, the determination of peak flow (pLDF) and time to peak flow (tpLDF) is of great interest in discriminating between subjects with peripheral arterial obliterative diseases and those who are healthy. However, the myogenic mechanism provokes marked oscillations on all LDF signals. Therefore, an accurate detection of the parameters is very difficult. The present study shows that wavelets are a powerful tool to overcome this drawback. Six different processes using several wavelets are tested on 44 signals recorded on 11 healthy volunteers. The results prove that thresholding coefficients of a multilevel wavelet decomposition does not allow a valuable computation of the parameters but that the reconstruction of the approximation branch is an efficient method to accurately determine pLDF and tpLDF. Using this latter method, mean results for a 3-min occlusion give pLDF = 46.80 a.u. and tpLDF = 17. 08 s. For a 2-min occlusion, pLDF and tpLDF are 39.19 a.u. and 11.63 s, respectively. For a 1-min occlusion, the results give pLDF = 36. 01 a.u., tpLDF = 8.48 s. Eventually, for a 30-s occlusion they give pLDF = 33.86 a.u. and tpLDF = 5.60 s. These results can now be compared with those obtained on pathological subjects.

Although the neurological and cardiovascular effects of Freons have been extensively described, the respiratory effects have been less well documented. We report four cases of occupational asthma following accidental exposure to bromochlorodifluoromethane (Halon 1211) due to release of the contents of a fire extinguisher. All subjects developed an irritative reaction of the upper airways and lower respiratory symptoms immediately after exposure. Non-specific bronchial hyperreactivity was present for at least two months in all subjects and was still present more than two years after exposure in one case. The diagnosis of reactive airways dysfunction syndrome can be adopted in at least three of these four cases.

The existence of a cutaneous pressure-induced vasodilation (PIV) has recently been reported. This paper proposes a signal processing methodology to improve PIV knowledge. Temporal variations of laser Doppler signals rhythmic activities are first analyzed on anesthetized rats. The results lead to a method that provides a better PIV understanding.

In the framework of the depth detection of tumor using the diffusion equation, a finite element method is proposed in order to solve the time-dependent light propagation in highly scattering media. A tumor-like object is positioned in the media. The finite element method tacks into account Robin type air-tissue boundary conditions. This study is devoted to the depth localization of a tumor enclosed into a breast tissue-like slab. Cartesian coordinates are used in order to solve the time-dependent diffusion approximation. A short laser pulse of 1ps is considered. The transillumination technique is able to laterally detect the objects when the source and detector are moved together on the same axis. In order to perform the depth localization of the inclusion, we were interested in a non-coaxial transillumination technique conjugated to interesting contrast functions based on the mean time of flight of photons. These functions allow to localize axially the inclusion using the high scattering processes. Thus, we performed first results of a depth indicator of a tumor. We now perform a parametric study. The optical properties of the slab are varying. Furthermore, different sizes of the objects are tested. Thus, the influence and the variation of these parameters on the depth indicator are shown. Our study demonstrates the possibility to deeply localize a tumor enclosed in a breast tissue using the high scattering processes induced by a tumor. To enhance the scattering processes, an interesting way is then to use recent nanoparticles allowing to modify the scattering coefficient.

A new time-frequency method based on the S-transform is presented to analyze the heart, respiration, myogenic, neurogenic and endothelial related metabolic activities on healthy subjects and on patients suffering from peripheral arterial occlusive diseases (PAOD). The analysis of the signal dynamics is presented at rest and during a local increase of temperature. The results show that five frequency bands, already known to correspond to the heart, respiration, myogenic, neurogenic and endothelial related metabolic activities, are clearly distinguishable. The dynamics observed on the patients are lower than on the healthy subjects. However, the heating increases the dynamic components of the two groups. The S-transform presents advantages that cannot be obtained with other time-frequency or time-scale representations.

In order to improve peripheral arterial occlusive diseases (PAOD) diagnoses, five de-noising algorithms based on a multiresolution analysis computed with wavelets are applied on reactive hyperemia signals obtained with the laser Doppler flowmetry technique. Results are presented on recordings acquired on patients suffering from PAOD and on healthy subjects.

The goal of the present work is to analyse multiple scattering in laser Doppler blood flowmetry reactive hyperaemia experiments. For this purpose, three different kinds of outputs from a laser Doppler flowmeter are studied: the concentration of moving blood cells (CMBC), the linearised unfiltered flux and the unlinerised unfiltered flux. Three vascular occlusion lengths of time are observed on eight healthy volunteers. For each reactive hyperaemia experiment, the difference between the linearised unfiltered flux and the unlinearised unfiltered flux is calculated to examine the multiple scattering. The latter is considered as a function of time and compared to blood flux and concentration of erthrocyte variations. This work shows that, during reactive hyperaemia, the multiple scattering is predominant when the CMBC signal reaches its peak, the latter occurring at the peak of perfusion. However, very rapidly the multiple scattering becomes negligible whereas the CMBC and the linearised flux still take high values. Moreover, the longer the occlusion length of time, the longer the presence of the multiple scattering.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Breast tissues can be investigated by means of the frequency- resolved spectroscopy, using the transmittance data. A model based on the Fourier transform of the time-resolved transmittance is firstly established, by considering the slightly compressed breast tissues as a finite homogeneous slab of different thicknesses. Two methods of determining the optical properties of this arrangement are presented. The former allows to use moderate modulation frequency of about 100 MHz, while the second requires a limited frequency range of 10 - 20 MHz, in accordance with the low frequency approximation. Under these conditions, computations reveal the potential of extracting the main optical tissue properties from the recorded phase angle shift and modulation linked to transmittance data, at fixed operating modulation frequency. In each case, graphical or numerical solutions can provide good estimates of both reduced scattering and absorption coefficients.

Laser Doppler flowmetry (LDF) is a non-invasive method to measure tissue blood flow. During reactive hyperaemia, the LDF signal increases to a peak and then returns to a resting value. A simplified model is developed to explain these variations. The emphasis is on simulating the effects occurring rather than on trying to mimic the anatomical structure of the microcirculation. A single blood vessel is therefore analysed. The increasing value of blood velocity is studied, and vasodilatation as well as vasoconstriction are taken into account. The model parameters are calculated using wavelets. For a 2-min occlusion on a healthy subject, the radius of the vessel is initially 15 microns, increasing to 24.6 microns at the peak, reached 14 s after the release of the occlusion. The model shows that the high value of the LDF signal during the initial phase of reactive hyperaemia is produced by an increasing number of erythrocytes in a cross-section, due to vasodilatation rather than an increase in moving blood cell velocities. Moreover, the rapidity of the vasodilatation and vasoconstriction effects determine the rapidity of the signal variations. The paper aims to give a basic solution to develop a numerical model.

The purpose of this work was to gain better overall picture to the thermal process involved in ablation of biological media performed by means of both continuous waves (cw) and pulsed laser irradiations. The theoretical analysis is based upon a computerized laser evaporative model. This scheme has been applied in order to clarify the following situations: (1) Ablation of tissue assimilated as water with finite absorption coefficient. (2) Tissue ablation by cw argon laser using gel (tissue-like phantom material) as a model system for tissue. (3) Skin ablation performed by pulsed Er:YAG laser radiation. In each case the role played by optical absorption in the dynamics of the ablation process is depicted. Typically, it appears that the position of the ablation front (or crater depth) and the transient ablation velocity are both influenced by tissue absorption while the steady-state stays independent on this parameter and evolves linearly with power density. Additionally, the ablation temperature beyond the moving front can reach a maximum higher than ablation threshold temperature. The peak temperature and its location are mediated by tissue type. Calculations show that for small absorption coefficients higher temperatures are reached at deeper levels. In contrast, at fixed absorption coefficient, the growing of the power density increases the peak temperature but reduces the penetration depth of the heated volume. The whole of computed data confirms that thermal laser ablation of tissue can be described as an explosive event and that a decrease of water content in the target alters the penetration depth which control the ablation rate.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A 27 year old white woman with a history of chronic eczema and episodes of serious infection of the chest, skin, and bone presented with acute respiratory failure. She was found to have a spontaneous right pneumothorax and a pneumatocele in the left upper lobe. Despite a left upper lobectomy she was left with chronic respiratory failure, bullous lung disease, and bilateral bronchiectasis. The hyperimmunoglobulinaemia E and recurrent infections syndrome was diagnosed only in adult life.