[A questionnaire assessing knowledge level concerning occupational asthma]. / Questionnaire d'évaluation du niveau de connaissances sur l'asthme professionnel.

INTRODUCTION: Screening for occupational asthma is should still be promoted. In order to improve the efficiency of any educational intervention we need to evaluate the patient's knowledge of the disease. OBJECTIVES: The aims were to evaluate objectively the knowledge level of Tunisian asthmatic patients concerning occupational asthma using a self-questionnaire in Arabic Tunisian dialect, then to conduct a validation process of the questionnaire. METHODS: We followed De Vellis's rules during all stages of redaction of the self-questionnaire. It contained 18 items allocated in 4 dimensions: knowledge about asthma; knowledge about occupational asthma; prognosis of occupational asthma; prevention of occupational asthma. A pre-test was conducted on 18 asthmatic patients to assess the clarity and comprehensibility of all the questions. The questionnaire was then applied to 107 asthmatic patients. RESULTS: The statistical analysis proved the discrimination value in 14 of the 18 items. The internal consistency of the questionnaire was demonstrated by a KR20 index of 0.731. Factorial analysis of the principal components showed the reliability of the questionnaire and of its uni-dimensional structure. The statistical findings proved the positive correlation between the mean scores of all its dimensions. CONCLUSIONS: Using this questionnaire in daily practice should inform health care providers about the level of knowledge of occupational asthma in the targeted population and improve the effectiveness of any further educational intervention.

Determination of urinary trans, trans-muconic acid reference values in general Tunisian population.

We wish to determine the urinary trans,trans-muconic acid reference values in the Tunisian general population, and evaluate the impact of several factors (age, gender, tobacco...) on these reference values. Urine samples were collected from 182 healthy Tunisian subjects who had not been occupationally exposed to benzene. This determination was performed by solid phase extraction sampling technique together with high performance liquid chromatography-photodiode array detector. Trans,trans-muconic values ranged from 0.003 to 0.618 mg/g creatinine, the 95% reference interval was: 0.004-0.36, and the 90% confidence interval of the upper reference limit was: 0.24-0.62 mg/g creatinine. Urinary trans,trans-muconic levels were significantly higher among smokers. Significant differences were also observed for the < 20 and the > or = 40 age groups. As a result urinary trans,trans-muconic background levels allow the biomonitoring of workers occupationally exposed to benzene at levels as low as 0.5 ppm. Age and tobacco, but not gender may affect the trans,trans-muconic reference values.

Measurement of bronchial responsiveness by forced oscillation technique in occupational epidemiology.

The performance of the forced oscillation technique (FOT) in the assessment of bronchial responsiveness on the methacholine challenge test was compared with that of forced expiratory volume in one second (FEV1) in 119 active workers with normal baseline pulmonary function. Changes in resistance (delta R0%), frequency dependence of resistance (delta P) and resonant frequency (delta F%) determined by the FOT were compared to the delta FEV1%. Receiver operating characteristic (ROC) curves were established to determine values of the changes in FOT parameters which corresponded to the best sensitivity and specificity for classifying the subjects as hyperresponsive or nonresponsive on the methacholine challenge test. Significant correlations were observed between delta FEV1% and delta R0%, delta P and delta F% respectively. The ROC curves showed the following cut-off values of FOT parameters to be the best values for classifying the subjects according to the presence or absence of 20% fall in FEV1: a 65% increase in R0 (sensitivity 75%; specificity: 76%); a decrease of 65 x 10(-3) hPa.l-1.s2 in P (sensitivity 58%; specificity 83%); a 50% increase in F (sensitivity 75%; specificity 62%). Our results suggest that the FOT is a useful test for assessment of bronchial hyperresponsiveness when compared to spirometry, and can be applied to epidemiological studies of a bronchial challenge test in normal active working populations.

Experimental study of the effects of a new protective cream against skin irritation provoked by the organic solvents n-hexane, trichlorethylene and toluene.

In a first experiment, the potential effectiveness of three cream formulations (A, B, C) against skin irritation due to n-hexane was evaluated using a guinea pig model. Semi-quantitative histopathological assessment of skin lesions were carried out. Due to interesting protective effects, cream formulation A (Travabon) was selected and further investigated. In a second series of experiments, this cream showed some protective effects against irritation due to toluene, but was not found efficacious against trichlorethylene irritation.

[Invasive and non-invasive studies of the protective action of a silicon-containing cream and its excipient in skin irritation induced by sodium laurylsulfate]. / Etudes invasive et non invasive du pouvoir protecteur d'une crème siliconée et de son excipient vis-à-vis de l'irritation cutanée induite par le laurylsulfate de sodium.

The purpose of our study was to evaluate the protective effect of a new silicone-containing barrier-cream (Anthydro) and its vehicle (Anthydro without silicone) in the prevention of cutaneous irritation by detergents. We therefore planned a study in several stages, using an anionic surfactant well known for its irritant properties: sodium laurylsulphate (SLS) in aqueous solution. In a first series of experiments, the protective effect of the Anthydro cream against SLS was studied by invasive methods on guinea-pigs in order to determine histologically the protective effect of the cream when a 10 p. 100 SLS solution was applied on the skin under occlusion during 24 hours (Square chambers, Van der Bend). Typical and reproducible lesions were apparent, and the protected sites were compared with the unprotected sites. In parallel, we used non-invasive methods (conductivity, transepidermal water loss and cutaneous blood flow) to determine in humans the protective effect of Anthydro cream in comparison with unprotected sites after application during 24 hours of patches soaked with a 5 p. 100 SLS solution on the forearms of 13 adult and healthy volunteers (Silver patch tests, Van der Bend). In both experiments the Anthydro cream was effective in reducing the SLS-induced cutaneous irritation. In a second series of experiments, the Anthydro barrier-cream was compared with its "base" (Anthydro without silicone) in terms of effectiveness, following the same experimental procedure (invasive on guinea-pigs, and non-invasive on humans). The base was shown to be effective in protecting against irritation. However, the histological lesions were less intense when the skin was protected by Anthydro than by its vehicle. Concerning the non-invasive methods in humans, no significant statistical differences appeared in the measurement of various parameters between the sites protected by Anthydro and the sites protected by the vehicle. These results lead us to suggest the existence of an essentially mechanical protective effect in which the silicone plays a very small part in terms of effectiveness. These experimental results necessitates further investigations to be extrapolated to occupational conditions without tests performed in industries and well-conducted epidemiological investigations.

Ring-shaped positive allergic patch test reactions to allergens in liquid vehicles.

In recent years, we have observed several "ring-shaped" positive allergic patch test reactions to allergens dissolved in a liquid vehicle, a more intense response at the periphery of the site of application than in the central part. The occurrence of such reactions was evaluated for formaldehyde, Kathon CG, hydrocortisone and hexamidine diisethionate. Possible explanations for such reactions include pressure and/or a capillary effect.