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Biomedical subjects

J F Dessanges

Publications and source records attributed to J F Dessanges.

At least 19 recordsLinked to original sources
PubMed1999

The effect of zafirlukast on repetitive exercise-induced bronchoconstriction: the possible role of leukotrienes in exercise-induced refractoriness.

BACKGROUND: Single doses of zafirlukast attenuate exercise-induced bronchoconstriction (EIB), but previous studies have not measured zafirlukast's effects after regular dosing or its duration of effect beyond 4 hours. OBJECTIVE: The purpose of this study was to assess the effects of zafirlukast 20 mg and 80 mg twice daily compared with placebo on exercise challenges performed at 2 and 8 hours after the last dose of regular administration. METHODS: Twenty-four adult patients with stable asthma taking beta(2)-agonists, inhaled corticosteroids, or both received treatment with zafirlukast (20 mg and 80 mg) and placebo. The patients were treated twice daily for 14 days in a randomized, double-blind, 3-way cross-over fashion, with a 7-day washout period between each treatment. Exercise challenges were performed at 2 and 8 hours after the morning dose on day 14. FEV(1) was measured before exercise and at set intervals after exercise until it returned to within 7% of its baseline value. RESULTS: Both zafirlukast treatments significantly reduced EIB, as measured by the area under the FEV(1) time curve after the 2-hour (P <.001) and 8-hour (P <.001) exercise challenges and maximum fall in FEV(1) at the 2-hour challenge (P <.001). The comparison at 8 hours between treatments was affected by the unexpected finding that EIB was less in the placebo group after the 8-hour challenge than after the 2-hour challenge, as measured by the within-group change in the maximum fall in FEV(1) (P <.001) and the area under the FEV(1) time curve (P =.0023). CONCLUSION: Regular zafirlukast treatment protects against EIB for at least 8 hours after regular dosing. A refractory period, which may be caused by exercise-induced leukotriene release, may last for up to 6 hours after the initial response to exercise.

Adolescent↗
PubMed1999

Quantification of the dose of inhaled flour: relation with nonspecific bronchial and immunological reactivities.

The aim of this study was to investigate the relationship between specific bronchial reactivity and respective nonspecific bronchial and immunological reactivities. Twenty-one patients underwent bronchial challenges with lactose and flour. The aerosol of particles was generated by a computer-controlled aerosolizer. Specific bronchial challenge results were expressed as the provocative dose of flour (PDf) that caused a 20% or 15% decrease in the forced expiratory volume in one second (FEV1). For each subject, the decrease in FEV1 observed during the challenge with flour was compared with the calculated lower limit of the 99.7% confidence interval for the lactose challenge. The subjects also underwent a nonspecific challenge with methacholine and a measurement of the specific immunoglobulin E against wheat. The inhalation of lactose did not significantly affect FEV1. Nine subjects had high reactivity to wheat flour with a PDf20 <400 microg. Five subjects had intermediate reactivity: FEV1 fell by <20% but by significantly more than that in the test with lactose. For 7 subjects, there was no significant change in FEVI for inhaled doses of flour over 1390 microg. The results for specific bronchial challenge were significantly correlated with those for the methacholine test (p<0.02). Positive skin tests and specific immunoglobulin E against wheat were observed more frequently in the high reactivity group. Specific bronchial challenge can be performed safely to establish precise dose-response curves. The provocative dose of flour causing a 20% decrease in forced expiratory volume in one second is useful for evaluating the degree of specific reactivity but is not suitable in cases of intermediate reactivity in which comparison with the lactose test is necessary. Specific reactivity is probably a function of immunological and nonspecific bronchial reactivities.

Adult↗
PubMed1998

[Nebulization: principles and generating process].

After a brief historical background, principles of nebulization are reviewed, i.e., factors at the origin of particle sedimentation, the procedure advantages and the importance of the particle size. Inhaled particles reach alveolar bronchioli via three mechanisms: impaction, sedimentation and diffusion. There are two different types of nebulizers: pneumatic and ultrasonic. To optimize its benefits nebulization should consist of a slow and deep inspiration followed by a pause in order to improve particle sedimentation. Nebulization should always be associated with kinesitherapy.

Administration, Inhalation↗
PubMed1998

Blood gas measurement during exercise: a comparative study between arterialized earlobe sampling and direct arterial puncture in adults.

Sampling arterialized earlobe blood is thought to be easier and less painful than direct arterial puncture, and to allow measurement of blood gas values during exercise without the need to insert an arterial cannula. However, arterialized earlobe oxygen tension (PO2) often underestimates arterial PO2 at rest, and is not fully validated during exercise. We have therefore conducted a prospective study to compare values of PO2 and carbon dioxide tension (PCO2) and the discomfort experienced by adult subjects undergoing the two methods of blood sampling during exercise. Seventy consecutive adult patients were studied. Blood samples were drawn simultaneously from the radial artery and arterialized earlobe of each patient during the last minute of an 8 min exercise. Values of PO2 and PCO2 were measured by means of blood gas electrodes. The correlation coefficients between the two samples were 0.92 for PO2 and 0.91 for PCO2. However, the bias and the limits of agreement between the two methods were wide for PO2 (mean+/-2SD of the differences between the two methods: 0.63+/-1.50 kPa (4.7+/-11.2 mmHg)). The bias and the limits of agreement were smaller for PCO2. Patients felt that the earlobe method was not associated with less discomfort than radial artery puncture. We conclude that arterialized earlobe blood oxygen tension is not a good substitute for arterial oxygen tension during exercise, and should not be used to assess arterial oxygen tension in adults during exercise.

Adult↗
PubMed1997

[Occupational asthma caused by buckwheat flour].

Buckwheat flour, mainly used for pancakes, may induce asthma following inhalation and anaphylactic reactions following ingestion. These allergic reactions are mediated by specific IgE and may be confirmed by skin test and radio-allergo-sorbent test. The occupational asthma of a patient working in pancake restaurant was confirmed by specific challenge test with a computerised device to generate particles. A very small amount of buckwheat flour (10 micrograms) induced an immediate fall of the FEV1 to 56% of the initial value. No bronchial reaction was observed with lactose nor with wheat flour. Specific bronchial challenge identifies the allergen responsible for asthma, measures the level of sensitization and thus can prevent the occupational exposure.

Adult↗
PubMed1996

Exhaled nitric oxide during acute changes of airways calibre in asthma.

It has been shown that endogenous nitric oxide (NO), measured in exhaled air, is increased in asthmatic subjects and after allergen challenge in sensitized animals. NO is also a paracrine molecule with some, though weak, bronchodilator effects. However, whether the amount of endogenous NO that originates in the lungs can reflect the degree of bronchial tone and airways calibre in asthmatic subjects has not yet been investigated. The aim of this study was, therefore, to determine whether NO production could be modified by acute changes of airways calibre in mild, nonatopic, asthmatic subjects. NO output was measured in the exhaled air of 14 steroid-free asthmatics, 8 steroid-treated asthmatics and 21 control subjects. In seven steroid-free asthmatics, exhaled NO was measured after methacholine challenge, and then after salbutamol-induced bronchial dilatation. Exhaled tidal breathing was collected for 30 s and NO in the exhaled air was measured with a chemiluminescence analyser. Both NO concentration and its output were significantly higher in the steroid-free asthmatic patients (15.6 +/- 1.5 parts per billion (ppb) and 6.3 +/- 0.7 nmol.min-1, respectively) as compared with the control subjects (8.9 +/- 1.0 ppb and 3.5 +/- 0.3 nmol.min-1, respectively; p < 0.001 for both) and with the steroid-treated asthmatic patients (11.3 +/- 3.3 ppb and 3.7 +/- 0.9 nmol.min-1, respectively; p < 0.05 for both). Neither methacholine-induced bronchial obstruction nor salbutamol-induced bronchial dilatation caused a significant change in exhaled NO. We conclude that NO production is higher in steroid-free than in steroid-treated asthmatics and in control subjects. Furthermore, NO production is not affected by acute pharmacologically-induced changes of airways calibre in asthmatic subjects. Our results suggest that NO production is a marker of airways inflammation rather than an endogenous modulator of bronchial tone in asthma.

Adult↗
PubMed1996

[Comparative study of the performance and ergonomics of nebulizers in cystic fibrosis].

This study had, as its aim, to test twelve nebulizers (6 jet, 6 ultrasonic) which are used in the treatment of cystic fibrosis. Devices were connected to a respirator in order to mimic the ventilation of a child and of an adult suffering from cystis fibrosis. Three medications: tobramycine, colistine and amiloride were nebulised. The volume of the recommended solution varied between 1.5 and 13 ml according to the manufacturer. During a session of ten minutes the ultrasonic nebulizer delivered an inhaled volume which was significantly greater than the jet (2.72 +/- 0.98 ml vs 1.22 +/- 0.59 ml, p < 0.0001) for the three drugs. Regarding granulometry, the fraction of particles between 0.5 and 5 microns, was higher with ultrasonic than with pneumatic nebulizer for tobramycine (67.1 +/- 10.7 vs 55.5 +/- 11.5%, p < 0.001) and amiloride (66.4 +/- 9.2% vs 58.1 +/- 15%, p < 0.05%). The variation of concentration due to nebulisation were independent of the type of apparatus but influenced by the drug since concentration was increased for tobramycine (+10.5 +/- 18.6%) and amiloride (+13.4 +/- 8/9%). In summary the effective fraction resulting from the inhalable fraction, from granulometry and from changes in concentration was significantly greater for ultrasonic than for jet nebrulizer (17.3 +/- 6.7% vs 9.7 +/- 9.6%, p < 0.001). This study underlines the great variability of the performance of aerosols generators and therefore the need for an accurate evaluation of nebulizer performances in order to prescribe the best nebulizer/drug association in clinical practice.

Administration, Inhalation↗
PubMed1995

Nebulizer performance: AFLM study. Association Française de Lutte contre la Mucoviscidose.

This study was conducted by the AFLM order to determine the performance characteristics of 12 commercially available nebulizers (6 ultrasonic and 6 jet) used in the treatment of cystic fibrosis (CF). The nebulizers were connected to a circuit which simulated the ventilation of a CF child and CF adult, and were tested using three drug solutions: tobramycin (T), colistin (C), and amiloride (A). Nebulizer performance was evaluated according to the volume of drug solution delivered in 10 min during the simulated inspiratory phase (VI), drug granulometry (G%), drug concentration modification in the nebulizer reservoir (delta C), and percentage of efficiently aerosolized drug EA%). The ultrasonic devices delivered a significantly higher VI than the jet nebulizers (p < 0.0001) for all three study drug. Ventilation rate did not influence VI. Regarding granulometry, higher percentages of T and A were found to be contained in droplets ranging from 0.5 to 5.0 micron following ultrasonic nebulization. Drug concentration modifications were independent of the nebulizer used but were influenced by drug type; overconcentrations of T and A were observed (delta C = +10.5 +/- 18.6 and +13.4 +/- 8.9%, respectively). On average, the ultrasonic devices achieved a higher EA% than the jet nebulizers (17.3 +/- 6.7 and 9.7 +/- 9.6%, respectively). This study highlights the significant variability in performance of different nebulizer types and empahsizes the importance of accurately testing nebulizers prior to clinical use so that the most efficacious nebulizer/drug combinations may be prescribed.

Administration, Inhalation↗
PubMed1992

Azelastine reduces allergen-induced nasal response: a clinical and rhinomanometric assessment.

The effect of azelastine 2 mg b.d. p.o. for 10 days on grass pollen-induced nasal responses in 16 patients with grass pollen allergic rhinitis has been assessed. The study was a double blind, randomized, placebo controlled, crossover trial, with a 10-14 day wash-out period. Patients were challenged with grass pollen before and after placebo and azelastine. The response was assessed by measurement of nasal resistance using active posterior rhinomanometry, by weighing nasal secretions, and by counting sneezes. The sensation of nasal obstruction was assessed with a visual analogue scale. After measurement of baseline total nasal resistance, doubling doses of allergen were sprayed into both nostrils at 15 min intervals until the nasal resistance was doubled. Cumulative doses of allergen that doubled prechallenge nasal resistance, numbers of sneezes and the amounts of nasal secretions were similar before azelastine as well as before and after placebo (cumulative dose, mean, (microgram): 2.3, 4.2 and 2.1 respectively, N.S.). After azelastine, the cumulative dose of allergen was increased (7.3 micrograms), and nasal secretions and the number of sneezes were decreased. The visual analogue scores were similar before and after azelastine as well as before and after the placebo. It is concluded that azelastine reduced the allergen-induced nasal responses.

Adult↗
PubMed1991

[Cough and bronchial obstruction induced by citric acid in smokers, occasional smokers and non-smokers].

We have studied cough and bronchial constriction induced by inhaling citric acid in 15 smokers with baseline airflow obstruction, in 13 occasional smokers and 13 non smokers. The threshold for cough was significantly higher in occasional smokers in relation to smokers and non smokers. Citric acid produced the same degree of bronchial constriction at the same time in smokers and occasional smokers: the maximum fall in forced expired volume (FEV1-VEMS) was recorded five seconds after inhalation of the citric acid (dose threshold) and there was no significant difference between the two groups. In the non smokers, the maximum fall in VEMS was recorded twenty seconds after inhalation of the citric acid and was significantly less in relation to that of the smokers and occasional smokers. In the smokers the degree of smoking could influence the fall of VEMS (% predicted). Cough and bronchial constriction after the inhalation of citric acid are probably related to different physiological mechanisms and are linked to the history of smoking.

Adult↗
PubMed1989

Ventilatory response to carbon dioxide during extradural anaesthesia with lignocaine and fentanyl.

Twenty-seven patients undergoing extracorporeal shock-wave lithotripsy or knee arthroscopy received extradural anaesthesia with 2% lignocaine plus adrenaline 1 in 200,000. They were allocated randomly to three groups, one receiving no fentanyl (n = 6), the two others receiving fentanyl 50 micrograms either extradurally (n = 15) or i.v. (n = 6). Three tests of sensitivity to carbon dioxide (Read's method) were performed successively on each patient: before operation and at 1 and 2 h after the extradural injection. Whereas lignocaine and adrenaline alone had no significant effects on basal ventilation and the ventilatory response to carbon dioxide, extradural fentanyl caused a slight reduction in resting ventilatory rate and ventilation at 1 and 2 h with no change in resting end-tidal carbon dioxide concentration. In addition, the slope of the ventilatory response to carbon dioxide was reduced slightly at 1 h and ventilation at end-tidal PCO2 of 7.3 kPa was reduced also at 1 and 2 h. Conversely, the same dose of fentanyl i.v. had lesser and shorter effects on ventilation at rest and during carbon dioxide rebreathing. Our results show that fentanyl 50 micrograms given extradurally caused slight ventilatory depression which is probably clinically unimportant.

Adult↗
PubMed1988

Local cellular and humoral responses to antigenic and distilled water challenge in subjects with allergic rhinitis.

We studied nasal responses to allergen, saline, and distilled water aerosol in 7 subjects with allergic rhinitis to determine whether they caused a similar release of mediators and influx of inflammatory cells into the nasal lumen. The subjects were challenged first with allergen and then with aerosols of distilled water and of normal saline in random order on separate days. We measured nasal airway resistance (Rn) by posterior rhinomanometry, measured the concentrations of protein, histamine, leukotrienes (LT) B4, C4, and D4, and platelet-activating factor (PAF-acether) and performed total and differential cell counts in nasal lavage fluid obtained before and after each challenge. Allergen challenge provoked a 2-fold or greater increase in nasal airway resistance in all subjects (mean increase = 12.2-fold). This response was associated with significant increases in protein, histamine, LTB4, and sulfidopeptide leukotrienes. 2-lyso-PAF-acether increased significantly, indicating activation of phospholipase A2, but PAF-acether was detected in only one subject. The total cell count increased from 55 +/- 44 x 10(3)/ml to 200 +/- 168 x 10(3)/ml; polymorphonuclear neutrophils increased from 11 +/- 22 x 10(3)/ml to 108 +/- 96 x 10(3)/ml, and eosinophils increased from 1.3 +/- 1.8 x 10(3)/ml to 10.6 +/- 15.3 x 10(3)/ml (p less than 0.05). Saline insufflation provoked insignificant changes in mean Rn, in the levels of protein and all inflammatory mediators, and in the number and types of cells in nasal lavage fluid. Distilled water insufflation also provoked an insignificant increase in mean Rn, but there was a 14-fold increase in one subject.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Nasal response to substance P and methacholine in subjects with and without allergic rhinitis.

We compared the rise in nasal airway resistance (NAR) provoked by topical application of substance P (SP) and of methacholine (MCH) in seventeen patients suffering from rhinitis and fourteen control subjects. Challenges with SP or MCH were separated by a week or more. NAR was measured by posterior rhinomanometry before and 10 min after intranasal administration of SP (10-40 nmol) or MCH (3-12 mumol). The two groups of subjects had similar baseline levels of NAR and similar small responses to buffered saline. Substance P but not MCH provoked cutaneous flushing in all subjects. Both SP and MCH provoked a significantly greater increase in NAR in patients suffering from rhinitis than in control subjects. The increase in NAR was dose-dependent, and on a molar basis, SP was 375-500-fold more potent than MCH. Pretreatment with 200 micrograms of a topically active anticholinergic agent, oxytropium bromide, prevented the rise in NAR caused by 12 mumol of MCH but not that caused by 40 nmol of SP in six patients suffering from rhinitis. We conclude that SP is absorbed across the nasal mucosa and causes cutaneous vasodilation, that MCH and SP cause a greater rise in NAR in patients suffering from rhinitis than in control subjects, that SP is about 500-fold more potent than MCH in increasing NAR, and that the rise in NAR caused by SP is not mediated by postganglionic parasympathetic mechanisms.

Administration, Intranasal↗