[Smoking in adolescents, saliva cotinine concentrations and respiratory disease]. / Tabaquismo en adolescentes, valores de cotinina en saliva y enfermedad respiratoria.

OBJECTIVE: To assess cotinine levels in the saliva of adolescents and the relationship between these levels, smoking habits and respiratory disease. PATIENTS AND METHODS: We studied 420 adolescents (54.7% boys and 45.3% girls) aged between 14 and 21 years (mean age, 16.4 +/- 1.32), from state and private schools in Tenerife. An individualized survey, based on the American Thoracic Society's model, was carried out and saliva cotinine concentrations were determined by radioimmunoassay. RESULTS: Distribution according to smoking habits was as follows: 26.5% were regular smokers, 11% were sporadic smokers, 3.6% were former smokers, 45.6% were passive smokers, and 13.4% were not exposed to smoking. Mean cotinine levels were 225.4 ng/ml in regular smokers, 19.5 ng/ml in sporadic smokers, 17.4 ng/ml in former smokers, 4.2 ng/ml in passive smokers and 2.2 ng/ml in individuals not exposed to tobacco smoke, which demonstrated the correlation between saliva cotinine concentrations and smoking habits (p=0.0001). The cotinine level in smokers of <10 cigarettes/day was 142,7 ng/ml and in smokers of >10 cigarettes/day it was 341,1 ng/ml (p=0.0001). A significant correlation was also found between cotinine concentrations and the number of cigarettes smoked regularly and in the last 24 hours before sample collection (p=0.0001). Lower respiratory tract infection (p=0.0001), chronic cough (p=0.0001) and bronchospasm on physical exercise (p=0.0001) were more frequent in adolescents with higher cotinine concentrations. CONCLUSIONS: Higher saliva cotinine concentrations were correlated with greater tobacco consumption and exposure to tobacco smoke. Adolescents with lower respiratory tract infections, chronic cough and bronchospasm on physical exercise had higher saliva cotinine concentrations.

[Usefulness of a gene amplification technique (LCx MTB) in the diagnosis of tuberculosis: preliminary results with different sputum samples]. / Utilidad de una técnica de amplificación genética (LCx MTB) para el diagnóstico de tuberculosis: resultados preliminares con muestras diferentes al esputo.

OBJECTIVE: To evaluate the use in non-sputum samples of a commercial molecular amplification kit (LCx MTB, Abbott Diagnostica) (LCx) for the diagnosis of tuberculosis. MATERIAL AND METHOD: Ninety-nine non-sputum samples from the same number of patients (bronchoalveolar, pleural and ascitic fluid, fecal samples, blood cultures, biopsies from different sites, cerebrospinal fluid, urine and gastric juices) and 14 sputum samples (10 from patients clinically suspected of having tuberculosis and 4 from patients diagnosed of tuberculosis and undergoing appropriate treatment for at least one month). All samples were LCx processed according to the manufacturer's instructions. The reference diagnosis was obtained by the Löwestein-jensen method and when results were inconsistent, we took into account the degree of clinical suspicion, response to treatment and histology. RESULTS: Seven of the 99 samples were positive by the LCx technique, and 6 of the 7 were also LJ positive; 1 could not be evaluated because of culture contamination. One LJ positive culture was LCx negative. Only one sample was positive by Ziehl-Neelsen (ZN) staining. Ninety-two samples were LCx negative, with 91 showing no growth at all. Sensitivity was 86% and specificity 98%. Atypical mycobacteria were detected in 4 cases, all of which were LCx negative. CONCLUSIONS: Diagnosis of tuberculosis by applying the LCx system to various types of samples other than sputum is simple, rapid, sensitive and specific.