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Biomedical subjects

A Bohadana

Publications and source records attributed to A Bohadana.

13 recordsLinked to original sources
PubMed2006

[Risk reduction strategies in smoking].

INTRODUCTION: Around the world, due to its high efficiency in delivering nicotine, cigarette is, by far, the first device used to consume tobacco. But, as far as health is concerned, cigarette is the worst nicotine delivery system and cleaner delivery systems would be welcome. In respect to tobacco smoking, up to now, most doctors have supported the "quit smoking or die" dogma. However, some smokers cannot or do not want to completely give up the consumption of nicotine. BACKGROUND: Indeed, while some smokers can stop smoking and, for some of them, simply switch to a nicotine replacement therapy (NRT), other smokers crave the acute effects associated with the rapid massive surge of nicotine delivered to the brain by tobacco smoke. Currently, this rapid nicotine "high" is mainly experienced by smoking cigarettes, thus explaining the high rate of smoking relapse. VIEWPOINT: Thus, for smokers who cannot totally give up nicotine, it is sound to evaluate the rationale for the use of tobacco products with possible lower toxicity than cigarette smoke. CONCLUSIONS: Unfortunately, this important question triggers off passionate statements, while scientific and experimental observations are still very tenuous. Furthermore, the tobacco companies, by producing new tobacco products and promoting the use of smokeless tobacco such as snus, put a constant pressure on the Public Health community.

Adolescent↗
PubMed2005

[Passive smoking].

INTRODUCTION: Environmental tobacco smoke is a recognized factor of morbidity and mortality. The first victims are children, sometimes starting from conception, but adults are not spared. In practice, evaluation of exposure to tobacco smoke can be achieved with more or less specific markers of tobacco smoke. CURRENT KNOWLEDGE: Exposure of the fetus to maternal smoking and of the infant to environmental smoke can have a serious sometimes life-threatening impact. Such exposure increases the risk of spontaneous abortion, ectopic pregnancy, intrauterine growth retardation, premature membrane rupture, preterm birth, retroplacental hematoma, placenta praevia, and sudden infant death. Adult respiratory and cardiovascular disease are also influenced by environmental smoke. In France passive smoking causes premature death of 3000 persons per year. PERSPECTIVES: Better knowledge of the risks of exposure to passive smoking can facilitate application of legislation with the objective of protecting non-smokers. CONCLUSIONS: Rigorous application of current legislation is important to achieve the stated goals of prevention of smoking as well as assistance to cease smoking.

Adult↗
PubMed2004

Mechanisms of chronic airway obstruction in smokers.

Studies over the past few decades have showed a clear association between cigarette smoking and the development of chronic airway obstruction. Yet, only a minority of smokers is affected so that in many, even heavy, smokers, pulmonary function remains within normal limits. While carcinogens have been well characterized, there is only limited information about the constituents of cigarette smoke responsible for inducing chronic airway obstruction. In addition, the associated risks factors for airway obstruction in smokers have not been totally identified. The present paper is a review of the recently accumulated facts concerning the intimate action of cigarette smoke at the level of large and small airways and lung parenchyma. The role of classical inflammatory cells such as neutrophils and alveolar macrophages is reviewed, but emphasis is put on recent evidence indicating the involvement of CD8 + T-lymphocytes and possibly eosinophils in the genesis of the structural changes leading to airways obstruction. The mechanisms by which airway inflammation and remodelling cause airway narrowing and airflow limitation are discussed, along with the associated loss of lung elasticity secondary to destructive emphysema. Other biological, epidemiological, physiopathological, and clinical aspects are analyzed, stressing such fundamental aspects as the defence mechanisms, the morpho-functional correlations, the identification of susceptible smokers, and the early detection of airway obstruction, both in specialized laboratories and in primary care.

Bronchitis↗
PubMed2000

Nicotine inhaler and nicotine patch as a combination therapy for smoking cessation: a randomized, double-blind, placebo-controlled trial.

BACKGROUND: Nicotine replacement therapy is an effective treatment for nicotine-dependent smokers. However, cessation rates are modest, and preliminary studies suggest that combination therapy may be superior. We compared the efficacy of the nicotine inhaler plus nicotine patch vs nicotine inhaler plus placebo patch for smoking cessation. METHODS: A double-blind, randomized, placebo-controlled trial was conducted in 400 subjects who had smoked 10 or more cigarettes per day for 3 years or longer. Group 1 (n = 200) received the nicotine inhaler plus nicotine patch (delivering 15 mg of nicotine per 16 hours) for 6 weeks, then inhaler plus placebo patch for 6 weeks, then inhaler alone for 14 weeks. Group 2 (n = 200) received the nicotine inhaler plus placebo patch for 12 weeks, then inhaler for 14 weeks. Inhaler was used at a rate of 6 to 12 cartridges per day ad libitum for 3 months and then tapered off. Main outcome measures were complete abstinence (self-reported) and expired carbon dioxide concentration less than 10 ppm. RESULTS: Group 1 vs group 2 complete abstinence rates were 60.5% and 47.5% at 6 weeks (P =.009), 42.0% and 31.0% at 12 weeks (P =.02), 25.0% and 22.5% at 6 months (P =.56), and 19.5% and 14.0% at 12 months (P =. 14). One-year survival analysis showed a significant association between abstinence and treatment with nicotine inhaler plus nicotine patch (P =.04). Mean nicotine substitution at week 6 was 60.1% (group 1) and 24.6% (group 2) (P<.001). At 12 months, the frequency of respiratory symptoms in abstinent subjects fell significantly and lung function showed a trend toward improvement. The most common adverse events were throat irritation (inhaler) and itching (patch). CONCLUSIONS: Treatment with the nicotine inhaler plus nicotine patch resulted in significantly higher cessation rates than inhaler plus placebo patch.

Administration, Inhalation↗
PubMed1997

Lung auscultation in airway challenge testing.

The appearance of wheezes and changes in inspiratory breath (vesicular) sound intensity (BSI) were monitored in patients undergoing routine methacholine challenge test (MCT). The results were compared with changes in spirometry and to airway hyper-responsiveness (AH). Fifty-four patients were examined. Spirometry was performed before and after the inhalation of cumulative doses of methacholine starting from 25 micrograms; a fall in forced expiratory volume in 1 s (FEV1) by 20% or more was considered as significant. Lung auscultation was performed by two observers simultaneously using a special stethoscope placed sequentially over the posterior right and left upper (interscapular region, 5 cm from the fourth thoracic vertebra) and lower lung zones (5 cm below the scapulae). Symptoms were recorded by the patients on a visual analogue scale. In 27 patients, the MCT was positive (MCT+) and in 27 patients it was negative (MCT-). Wheezes were identified at PD20 in 12 MCT+ patients while reduced BSI alone was found in 11 patients; in four patients, auscultation was normal. In 20 MCT+ patients, either wheezes, diminished BSI or both were heard, one to several steps before reaching PD20. In the MCT- group, wheezes were detected in two patients and diminished BSI in four. In MCT+ patients, the mean (+/-SD) perception of symptoms at end-challenge was 33% (+/-26), whereas in MCT- patients, it was 13.6% (+/-22). Complete inter-observer agreement was found in 95.7% of auscultations performed (Kappa coefficient = 0.846). Coupled to spirometry, lung auscultation may prove useful in airway challenge testing provided the concept is accepted that wheeze appearance and, by extension, an acute decrease in BSI, is as legitimate a manifestation of AH as a fall in FEV1.

Adolescent↗
PubMed1995

Forced oscillation technique (FOT): a new tool for epidemiology of occupational lung diseases?

The aim of this study was to evaluate the usefulness of the forced oscillation technique (FOT) in the assessment of occupation-related airway changes. The forced oscillation technique and conventional lung function tests were applied in 80 underground coalface workers, aged 35-48 yrs, with chest roentgenogram films classified 0/1 or 1/0 according to the International Labour Office (ILO) classification (G group), and two control groups matched for age and smoking habits. The first control group, was made up of face-workers having normal chest radiographs, whilst the second comprised underground non-face-workers with normal chest radiographs. Spirometric, plethysmographic and transfer factor of the lungs for carbon monoxide single-breath (TL,CO,sb) indices revealed no significant differences between the three groups. As regards the forced oscillation technique, a higher value of resistance/frequency slope (Pa.L-1.s2) was found in the G group compared with the control groups; 2.11 vs 1.06 in the face-workers, and 1.58 in the underground workers. In all three groups, the forced oscillation technique indices (mean resistance (R), resistance at zero frequency (RO), resistance/frequency slope (S), and resonant frequency (fo)) were found to be higher in subjects having a decreased forced expiratory volume in one second (FEV1) (< or = 90% predicted) or a mildly obstructive pattern of ventilatory function, even though this did not reach statistical significance in each of the groups. These findings together with the feasibility and acceptability of the forced oscillation technique would suggest that it may be a suitable tool for epidemiological studies of occupational respiratory diseases.

Adult↗
PubMed1983

Effects of induced hypotension on breathing pattern in halothane-anaesthetized man.

The effects of hypotension induced by trimetaphan on ventilatory control were assessed in sixteen normal subjects under halothane anaesthesia. The breathing pattern, mouth occlusion pressures, lung mechanics, acid-base balance, and arterial blood gases were analysed before and during trimetaphan infusion. During induced hypotension, the only significant change in the ventilatory variables was an increase in the ratio of inspiratory duration to total cycle duration from 0.39 +/- 0.05 (SD) to 0.42 +/- 0.03; P less than 0.01. The average minute ventilation remained unchanged. No modification in lung mechanics was observed, but all subjects developed a slight but significant hypocapnic alkalosis: PaCO2 was reduced from 5.5 +/- 0.4 to 5.2 +/- 0.4 kPa (P less than 0.001) and pH increased from 7.34 to 7.36 (P less than 0.05), without change in standard bicarbonate concentration. Our data indicate that the reduction in sympathetic nervous system activity induced by trimetaphan infusion in spontaneously breathing man causes only a minor alveolar hyperventilation. The weak respiratory response to hypotension suggests that changing peripheral afferent activity has little influence on the typically rapid breathing pattern induced by halothane.

Acid-Base Equilibrium↗
PubMed1979

Comparison of various methods for reading maximal expiratory flow-volume curves.

To determine the best procedure for reading maximal expiratory flow-volume curves 2 sets of 5 curves were obtained one hour apart in 89 subjects and processed digitally according to 8 different methods. Four indices were considered: the forced expiratory flows at 25, 50, and 75 per cent of the forced vital capacity, and the maximal mid-expiratory flow. When selecting the curve yielding the largest forced vital capacity or the largest sum of forced vital capacity and forced expiratory volume in 1 sec, flow values were significantly lower (P less than 0.001) and were often less reproducible than those obtained with most of the other methods. Computing the mean of the indices among the curves with the 2 largest forced vital capacities also provided comparatively low values, but with with better reproducibility. In contrast, maximal flows were probably overestimated by using the highest values among the curves having forced vital capacity or a surface area within 5 per cent of the largest, or when reading the indices on a composite curve obtained by superimposing individual breaths at residual volume. More reproducible and, probably, unbiased data may be drawn from the composite curves obtained by superimposing the breaths either at total lung capacity or on the descending limb.

Adult↗
PubMed1976

Primary diffuse pulmonary amyloidosis with monoclonal gammopathy.

A rare case of primary diffuse amyloidosis of the lung with an abnormal monoclonal protein is described. The diagnosis was confirmed by an open-lung biopsy. The different classifications of amyloidosis as well as the relationship between the immunoglobulins and the pathogenesis of amyloid disease is discussed.

Aged↗
PubMedDate not supplied

[Harmonic content of the flow signal during forced expiration in normal man (author's transl)].

In order to define the minimal frequency response requirements for spirometric measurements, the harmonic content of forced expiratory flow has been assessed in 63 healthy subjects. The amplitude of the harmonics has been found to decrease almost exponentially with increasing frequency. On the average, the cumulated frequency content beyond 10 Hz represented less than 5% of the total frequency content in men, and less than 3% in women. No significant difference has been observed between male smokers and non-smokers. The harmonic content per unit frequency has been found to be correlated to maximal flows at middle and low lung volumes and to maximal mid-expiratory flow up to 4 Hz. For FEV1, maximal flow at 75% of the vital capacity and, particularly, peak expiratory flow rate (PEFR), the correlations were still significant at quite higher frequencies. The data suggest that, except for PEFR, all these indices may be obtained with a good accuracy when the frequency response of the equipment is flat up to 5-7 Hz.

Adult↗