Automatic landmarking as a convenient prerequisite for geometric morphometrics. Validation on cone beam computed tomography (CBCT)- based shape analysis of the nasal complex.

Manual landmarking is used in several manual and semi-automated prediction guidelines for approximation of the nose. The manual placement of landmarks may, however, render the analysis less repeatable due to observer subjectivity and, consequently, have an impact on the accuracy of the human facial approximation. In order to address this subjectivity and thereby improve facial approximations, we are developing an automated three-dimensional (3D) method based on an automatic dense landmarking procedure using non-rigid surface registration. The aim of this study was to validate the automatic landmarking method by comparing the intra-observer errors (INTRA-OE) and inter-observer errors (INTER-OE) between automatic and manual landmarking. Cone beam computed tomography (CBCT) scans of adult South Africans were selected from the Oral and Dental Hospital, University of Pretoria, South Africa. In this study, the validation of the automatic landmarking was performed on 20 3D surfaces. INTRA-OE and INTER-OE were analyzed by registering 41 craniometric landmarks from 10 hard-tissue surfaces and 21 capulometric landmarks from 10 soft-tissue surfaces of the same individuals. Absolute precision of the landmark positioning (both on the samples as well as the template) was assessed by calculating the measurement error (ME) for each landmark over different observers. Systematic error (bias) and relative random error (precision) was further quantified through repeated measures ANOVA (ANOVA-RM). The analysis showed that the random component of the ME in landmark positioning between the automatic observations were on average on par with the manual observations, except for the soft-tissue landmarks where automatic landmarking showed lower ME compared to manual landmarking. No bias was observed within the craniometric landmarking methods, but some bias was observed for capulometric landmarking. In conclusion, this research provides a first validation of the precision and accuracy of the automatic placement of landmarks on 3D hard- and soft-tissue surfaces and demonstrates its utilization as a convenient prerequisite for geometric morphometrics based shape analysis of the nasal complex.

[Internet and video games among students of Reunion Island in 2010: uses, misuses, perceptions and associated factors]. / Internet et jeux vidéo chez les étudiants de La Réunion en 2010 : usages, mésusages, perceptions et facteurs associés.

BACKGROUND: Describe the uses of Internet and video games and quantify associated problematic uses. METHODS: Information on student practices concerning the use of the Internet and video games was collected with a self-administered questionnaire. Problematic uses were identified with specific tools (Young criteria and Tejeiro criteria) and with self-evaluative questions. Information on life events with traumatic potential and use of psychoactive substances was also collected. Logistic regression models were applied to identify possible associated factors. RESULTS: Based on a sample of 1119 subjects, this study showed that students in Reunion Island are very concerned by the uses of the Internet and video games (98% and 46% of respondents). The prevalence of problematic use of the Internet accounted for 6% of respondents. Problematic uses of video games involved 8% of students (18% of gamers). Young people seemed unaware of their problematic practices and were seeking informations. The public respondent was also characterized by vulnerable situations (traumatic events induring their lives, consumption of psychoactive substances). Significant associations (with no identified causality) were examined, in particular between problematic uses of Internet and video games, and life events with traumatic potential. CONCLUSION: These first estimates of the prevalence of problematic use of Internet and video games on Reunion Island are important to promote locally collective awareness about these modern addictions. These results will be used to guide local actions of prevention and care, especially among younger generations. But it is necessary to conduct further work to better identify the factors associated with these problematic uses (determinants, comorbidities addictive…).

[Exposition markers: mineralogical analysis in the sputum and the bronchoalveolar lavage--asbestos bodies--uncoated fibres]. / Les marqueurs de l'exposition: analyses biométrologiques dans l'expectoration et le LBA - corps asbestosiques - fibres non gainées.

The aim of mineralogical analysis of lung tissue, bronchoalveolar lavage (BAL) and sputum is to characterize individuals' exposure to asbestos fibres by identifying markers of this; asbestos bodies (AB) and uncoated fibres. The techniques of mineralogical analysis, habitually used to identify AB and uncoated fibres, are respectively optical microscopy (OM) and analytical electronic microscopy (EM). Correlations between levels of retention of AB in lung tissue, BAL and sputum have been established and validated threshold values indicating a high probability of significant exposure exist. These results must be interpreted in the context of clinical and occupational information. Mineralogical analysis is not suitable for use in routine medical screening but it can be considered when a source of exposure is not evident from the questionnaire since a positive analysis of BAL or of sputum is highly specific and thus useful to confirm an important retention of asbestos in the lung, which justifies medical follow-up. A negative result does not exclude previous significant asbestos exposure (frequent false negatives occur especially in sputum and biopersistence of chrysotile is lower than for amphiboles). Thus it can be a complementary tool for the assessment of asbestos exposure but its use imposes conditions for the collection and handling of samples.

[Exposure to asbestos and the indoor environment]. / Situations d'exposition à l'amiante et environnement intérieur.

A link between the inhalation of asbestos fibres and the outcome of benign and malignant respiratory diseases has been established from numerous epidemiological data in occupational settings. Occupational exposure limit values have been established with a gradual lowering of these over time. Conversely, there are few epidemiological data dealing with exposure in the indoor environment. However, numerous materials and products containing asbestos (MPCA) are present in the indoor environment, due to their widespread use in the construction sector in the years between 1960 and 1990. The regulations were changed from the late 1990s, leading to a systematic inventory of the presence of asbestos-containing materials in buildings. The aim of this manuscript is to clarify the different types of MPCA encountered in the indoor environment, to describe the techniques used to highlight asbestos depending on the nature of the materials, the regulatory requirements relating to asbestos in non-occupational situations, and to update on the state of knowledge on asbestos-related diseases in the indoor environment.

Anthracofibrosis attributed to mixed mineral dust exposure: report of three cases.

Anthracofibrosis, defined as bronchial luminal narrowing with black pigmentation of the overlying mucosa, has been attributed to tuberculosis. Three patients with anthracofibrosis without mycobacterial infection are described who had previous occupational exposure to mixed dusts. CT scans showed calcified hilar lymph nodes in two patients. Surgical biopsy in one patient and autopsy in another revealed fibrotic lymph nodes with black pigmentation. Mineralogical analysis by transmission electron microscopy of pulmonary, hilar and/or bronchial samples found high levels of particle retention, raised percentages of free crystalline silica and mica in two patients, and free crystalline silica, kaolin and other silicates in the third. No evidence of any other contributory factor was found, suggesting that mixed mineral dust was the most probable cause. These observations suggest that exposure to mixed mineral dust should be added to the aetiology of anthracofibrosis.

Occupational exposures and lung cancer in New Caledonia.

AIMS: To study the associations between occupational exposures and the risk of lung cancer in New Caledonia. METHODS: All cases diagnosed between January 1993 and December 1995 (228 lung cancers) and 305 population controls were included. Detailed information on lifetime job history, smoking, and other potential risk factors was collected by interview. Occupational exposures were assessed from the questionnaires by an industrial hygienist, without knowledge of case-control status. RESULTS: No significant association was found with exposures related to nickel mining and refining, the main industrial activity in the territory. Among men, an excess risk of lung cancer was found for bus and truck drivers. Increased risks were also observed in men with the highest level of cumulative exposure to cleaning products and inorganic fertilisers. Exposure to field dust was associated with lung cancer risk in both sexes, and risk increased with cumulative exposure level. In some areas tremolite asbestos derived from local outcroppings was used as a whitewash. The association between exposure to field dust and lung cancer was limited to men and women exposed to this whitewash-that is, living in areas where the soil may contain tremolite. CONCLUSION: This study shows several associations between occupational exposures and lung cancer. The findings suggest that exposure to tremolite fibres from cultivated fields may increase the risk of lung cancer in New Caledonia.

[Bronchial anthracosis and pulmonary mica overload]. / Anthracose bronchique et surcharge pulmonaire en micas.

INTRODUCTION: The discovery of anthracotic plaques generally suggests either a history of tuberculosis or occupational exposure to dust. Other etiologies should, however, be considered. CASE REPORTS: A 60-year-old Iranian woman presented with a history of dyspnoea and with chest radiography demonstrating calcified hilar lymph nodes and interstitial lung disease. Pulmonary function tests revealed airway obstruction. A diffuse bronchial inflammatory appearance accompanied by anthracotic plaques was found at bronchoscopy, which prompted transmission electron microscopy analysis of non-fibrous mineral particles in the bronchoalveolar lavage fluid (BALF). This demonstrated the presence of an alveolar particle count greater than 10(7) particles/ml (p/ml), significantly more than that found in 42 BALF samples taken from controls without a history of occupational dust exposure (4,4.10(5) p/ml). Furthermore, the analysis also revealed an abnormally elevated proportion of mica particles (64%). Two other individuals, a 68 year-old Moroccan woman and a 70-year-old Algerian woman, who had anthracotic plaques, but no radiological evidence of interstitial lung disease, also underwent mineral analysis of BALF. Neither were found to have a raised alveolar particle count, but the mineral profile showed an abnormally elevated proportion of micas (62%) for one patient, and silica crystalline (40%) as well as micas (32%) for the other patient. CONCLUSIONS: Even if mica is present in 30 to 90% of the BALF, the results observed in these three patients raises the possibility of non-occupational environmental exposure and that anthracotic plaques might be associated with domestic pollution.

Asbestos bodies in the sputum of asbestos workers: correlation with occupational exposure.

A cross-sectional medical survey including collection of three consecutive sputum samples was carried out among 270 retired workers of a textile and friction materials factory, in order to investigate the relationship between asbestos body identification and asbestos exposure. The individual cumulative asbestos exposure, determined by means of a plant-specific job-exposure matrix based on asbestos air measurements in the workshops, proved to be heavy with a mean cumulative exposure of 217 fibres x mL(-1) x yr. Macrophages and asbestos bodies were identified in sputum samples by light microscopy. The lung origin of the sputum, suggested by the presence of macrophages and/or asbestos bodies, was confirmed in 82.6% of subjects, and 53% of these samples were positive for asbestos bodies. The prevalence of asbestos bodies was not related to sex, smoking status or latency. Conversely, multivariate analysis showed a positive relationship with cumulative exposure, duration and intensity of exposure to asbestos, as well as age and time since retirement. These findings suggest that sputum analysis for asbestos bodies may remain a relevant and noninvasive marker of heavy occupational exposure to asbestos, even years after retirement. Owing to the new perspectives in lung cancer screening, it might contribute to the identification of high-risk subjects.

Cytokine profiles in immunocompetent persons infected with Mycobacterium avium complex.

To evaluate the immunologic factors that contribute to protection against Mycobacterium avium complex (MAC), cytokine production by peripheral blood mononuclear cells (PBMC) from human immunodeficiency virus-negative persons with pulmonary MAC (MAC patients) and healthy control subjects with a delayed hypersensitivity skin test response to M. avium sensitin (MAS-positive control subjects) was measured. In MAC patients, mycobacterium-stimulated PBMC produced higher concentrations of interleukin (IL)-10 but lower concentrations of interferon (IFN)-gamma, IL-12, and tumor necrosis factor (TNF)-alpha, compared with PBMC from MAS-positive control subjects. Immunolabeling for intracellular IL-10 revealed that this cytokine was produced by both monocytes and T cells. Alveolar macrophages produced TNF-alpha and IL-10 in response to MAC, which suggests that these cytokines are produced in the lungs of patients with pulmonary disease caused by this pathogen. Our findings suggest that IFN-gamma, TNF-alpha, and IL-12 contribute to protection against MAC, whereas IL-10 is immunosuppressive.

Environmental exposure to tremolite and respiratory cancer in New Caledonia: a case-control study.

A case-control study on respiratory cancers was conducted in New Caledonia (South Pacific), where a high incidence of malignant pleural mesothelioma had been observed. The disease pattern suggested an environmental exposure to asbestos. The first results showed that, in some areas, tremolite asbestos derived from local outcroppings was used as whitewash (locally named "pö"). All cases diagnosed between 1993 and 1995 (including 15 pleural mesotheliomas, 228 lung cancers, and 23 laryngeal cancers) and 305 controls were included in the study. Detailed information on past or present use of the whitewash, residential history, smoking, diet, and occupation was collected. The risk of mesothelioma was strongly associated with the use of the whitewash (odds ratio (OR) = 40.9; 95% confidence interval (CI): 5.15, 325). All Melanesian cases had been exposed. Among Melanesian women, exposure to the whitewash was associated with an increased risk of lung cancer (OR = 4.89; 95% CI: 1.13, 21.2), and smokers exposed to po had an approximately ninefold risk (OR = 9.26; 95% CI: 1.72, 49.7) compared with women who never smoked and had never used the whitewash. In contrast, no association was noted between exposure to pö and lung cancer risk among Melanesian men, probably because of lower exposure levels. Among non-Melanesians, the numbers of exposed subjects were too small to assess the effect of exposure to po. There was no indication of elevated risks for the other cancer sites.

[Assessment of exposure to asbestos]. / Evaluation des expositions à l'amiante.

The aim of the study is to present the principles of assessing asbestos exposure in two different contexts: that of a patient suffering from pleuropulmonary pathology that could be attributed to asbestos and that of a group possibly exposed to asbestos. In the first case this evaluation concerns past exposure and depends typically on information obtained during the course of an interview with the patient. In the second case, the exposure is assessed by atmospheric analysis. Jobs in which occupational exposure to asbestos occurs should be examined, the tasks which entail this exposure and objects containing asbestos are discussed in the first part of the article. The accent is placed on the source of exposure, and the use of materials containing asbestos outside the asbestos industry. Some guidelines enabling the appreciation of the intensity of asbestos exposure as a function of the jobs involved and the objects handled are suggested. Regulations and the principle of quantifying asbestos in the atmosphere during direct exposure in the working environment on the one hand and during the course of passive exposure in the environment on the other are discussed in the second part of the article.

[Measurement of asbestos fibers in the air: description and limitations of the measuring techniques used]. / Métrologie des fibres d'amiante dans l'atmosphère: description et limites des techniques de mesurages utilisées.

Since the beginning of this century a wide range of methods were used to evaluate the asbestos exposure of workers. Instruments such as the konimeter, thermal precipitator, impinger or tyndallometer were employed to collect dust samples. Currently, the membrane filter method associated with phase contrast optical microscopy is widely accepted. These different sampling methods are presented in this paper and the relationships between asbestos concentration recorded by means of methods used in the past and with the current membrane filter method or with direct-reading instruments are discussed. Emphasis is put on the difficulty to use such relationships which were often established for specific situations (in the mine industry for instance). For non occupational exposure the use of electron microscopy methods is evaluated.

[The assessment of asbestos exposure]. / Evaluation des expositions à l'amiante.

The aim of the study is to present the principles of assessing asbestos exposure in two different contexts: that of a patient suffering from pleuropulmonary pathology that could be attributed to asbestos and that of a group possible exposed to asbestos. In the first case this evaluation concerns past exposure and depends typically on information obtained during the course of an interview with the patient. In the second case, the exposure is assessed by atmospheric analysis. Jobs in which occupational exposure to asbestos occurs should be examined, the tasks which entail this exposure and objects containing asbestos are discussed in the first part of the article. The accent is placed on the source of exposure, and the use of materials containing asbestos outside the asbestos industry. Some guidelines enabling the appreciation of the intensity of asbestos exposure as a function of the jobs involved and the objects handled are suggested. Regulations and the principle of quantifying asbestos in the atmosphere during direct exposure in the working environment of the one hand and during the course of passive exposure in the environment of the other are discussed in the second part of the article.

The use of a new static device based on the collection of the thoracic fraction for the assessment of the airborne concentration of asbestos fibres by transmission electron microscopy.

A new static device, the CATHIA sampling head, based on the collection of the thoracic fraction is proposed for the assessment of the airborne concentration of asbestos fibres by transmission electron microscopy. By comparison with a standard aerosol sampling head, it has been shown that this sampler reduces the total mass concentration, but does not introduce any change in the most common index used to characterize an asbestos aerosol fibre, that is the concentration of fibres with length greater than 5 microns, diameter less than 3 microns and length to diameter ratio greater than 3. The homogeneity of the deposited dust on the collection filter favours the use of this sampling head with both the indirect and direct preparation methods.

[Potential role of environmental and domestic exposure to tremolite in pleural cancer in New Caledonia]. / Rôle potentiel de l'exposition environnementale et domestique à la trémolite dans le cancer de la plèvre en Nouvelle Calédonie.

A previous study of respiratory cancers in New Caledonia (1978-1987) showed an excess risk of pleural cancer in this South Pacific French Territory, leading to the identification of an environmental pollution. In some villages, the residents use for their houses a whitewash made from a rock derived from local outcroppings. Analysis of samples of rock and whitewash showed that they consisted of tremolite asbestos. High levels of tremolite were detected in airborne samples collected in these villages and in biological specimens of patients with pulmonary cancer or mesothelioma; the concentrations of fibers are up to 78,000 fibers per litre of air and 44 millions of fibers per gramme of dry tissue. Besides the whitewash, the environmental exposure to tremolite fibers could also be associated with certain occupations. A case control study under process will allow the estimation of respiratory cancer risks associated with the exposure to tremolite.