[Inhalation therapy: provocation tests, infectious risks, acute bronchiolitis and ENT diseases. GAT aerosolstorming, Paris 2011]

Communications from the 2011 meeting of the GAT are reported in this second article on the practical management of bronchial provocation tests and infectious risks associated with the use of nebulization. Recent advances on the role of nebulized hypertonic saline in the treatment of acute bronchiolitis in infants and of the nebulization in sinusal diseases are also reported.

[A survey of nebulization practices in France conducted in 2004 by the GAT]

METHODS

A questionnaire was sent to 50 000 general practicioners (GP) and specialists.

RESULTS

4,898 physicians (9.4%) responded, including 59.1% GP, 16.9% pneumologists, 13% pediatricians and about 10% other specialists, ENT, allergologists, and intensivists. The main reason for pneumologists to prescribe nebulization was the efficiency on long term of approved drugs. GP prescribe nebulization for its local effects, using unapproved drugs, on short periods of time, especially in COPD, asthma, bronchitis and tracheitis/laryningitis. Although pneumologists have been trained during their fellowship and do not ask for further education, MG have learned by their own experience and are asking for further education.

CONCLUSION

This study should help to develop teaching programs on nebulization with the aim to optimize its practice.

N.U.A.G.E.S: A survey of nebulisation practice in France with regard to ERS guidelines

A survey of nebulisation practice in France was conducted under the aegis of the French respiratory society in 2004.

METHODS

Analysis of a questionnaire was obtained from 3674 physicians.

RESULTS

A total of 2439 physicians were general practitioners (GPs), 698 were chest physicians, and 537 paediatricians. The main reasons to use nebulisation are (1) for chest physicians efficacy in treating various pathologies with long-term administration (1 wk to 1 month) of approved drugs, and (2) for GP's local action properties. While chest physicians learned about nebulisation during their university training and do not ask for additional information, GPs learned by practical experience or from colleagues and ask for further information.

CONCLUSION

This study will help to develop targeted educational programmes on nebulisation practice.

[Prospective evaluation of the method of measurement of the peak nasal inspiratory flow (PNIF) in allergic rhinitis. Observational study "Pratic in ORL"]

OBJECTIVES

To establish the ENT specialists's interest for the nasal obstruction measurement by the Peak Nasal Inspiratory Flow (PNIF) for the primary care medical management of patients with allergic rhinitis.

MATERIAL AND METHODS

A nation wide mail survey was conducted on the whole set of 2,800 French ENT specialists. Physicians had to use the PNIF in 4-consecutive patients with allergic rhinitis and assess through a questionnaire their interest for this tool.

RESULTS

About 8% of all ENTs (n = 228) responded. 65.3% of them had used the PNIF with their 4 patients, 29.7% used it in only 1 to 3 of their patients, and 5% did not use it at all. The PNIF was mainly used in moderate to severe rhinitis (94%) in contrast with mild rhinitis (32%) and in persistent rhinitis (94.2%) compared to intermittent rhinitis (54.8%). The primary motivation to use the PNIF on a systematic basis was to quantitatively assess nasal obstruction and to obtain an objective measurement of nasal obstruction. Conversely, the reasons for not using the PNIF were the needless of an objective measurement of nasal obstruction, the drawback of the PNIF in the patient physician relationship and lack of patient's acceptance of the device. Most physicians considered training for a correct usage of the PNIF was easy. Finally, about 2 thirds of the sample gave a positive rating on the usefulness of the PNIF for their patients.

CONCLUSION

This study demonstrates the interest of the practitioners to dispose of a simple and reliable tool for the follow up of nasal obstruction in allergic rhinitis.

[Dry powder inhalers in extreme clinical situations]

INTRODUCTION

Dry powder inhalers (DPIs) require a certain threshold of inspiratory effort to generate respirable particles. We undertook a literature review to determine whether this may, in particular clinical settings (young children, elderly subjects, acute or chronic respiratory obstructive syndromes - asthma and COPD), constitute a limitation on their use.

STATE OF THE ART

Currently marketed DPIs exhibit different technical characteristics. Many factors may influence their efficacy, so that the predictive utility of in vitro tests is limited. Published clinical studies indicate that aerosol therapies inhaled with DPIs show clinical efficacy even at low inspiratory air flows in adults and children with acute asthma, in acute bronchoconstriction experimentally provoked by methacholine or histamine, in acute asthma attacks in adults and children, and in COPD-related airway obstruction. The efficacy of DPIs appears comparable to that of p-MDIs or nebulisation. However, the studies often have some limitations (including limited statistical power and patient selection) that may affect their value.

PERSPECTIVES

The published studies analysed suggest that DPIs may be used in the great majority of clinical situations, subject to careful patient education. Nevertheless, p-MDIs with spacers remain recommended by international guidelines for children under the age of 6.

CONCLUSIONS

Additional well-designed clinical studies remain desirable to establish firmly the efficacy of DPIs in these situations.

A history of nebulization

The simplest and most natural route of drug delivery to the lungs is the inhaled one. From the historical and medical point of view, it was a Greek, Pedanus Discorides, the father of the science of pharmacy, who, during the first century prescribed inhaled fumigation. Pipes were also used to inhale hallucinogenic substances. All shamans knew the psychotropic effects of poisonous plants such as Datura stramonium, especially Red Indians, in their peace calumets; but Indians of Madras used fumigations of Datura ferox to treat asthma. Since 1803, this therapeutic was imported in Great Britain and cigarettes with leaves of datura were used by asthmatics until 1992. In the middle of the nineteenth century, to treat grapevines diseases and in response to the fashion of inhaling thermal waters, spray technology was developed for the effervescent waters at the thermal spas. The onslaught of tuberculosis, similar to AIDS a century later, brought back into practice the inefficacious use of antiseptic aerosol therapy. With the discovery of adrenaline, ephedrine aerosols enjoyed a rebirth. The perfecting of jet nebulizers by R. Tiffeneau, father of FEV1 and M.B. Wright, father of peak-flow, allowed a better practice of inhalotherapy. In 1949, the United States, ultrasonic nebulizers made their first appearance in the form of humidifiers, but doctors were quick to add medications to produce therapeutic aerosols. After 150 years, with the improvement of nebulizer systems and new nebulized medications, the nebulization story is still not concluded.

[Specific bronchial provocation test with solid aerosols. Quantification of results]

OBJECTIVES

To determine 1) the level of specific bronchial reactivity by challenge with flour and 2) the criteria of positivity using a new method for the expression of the results.

METHOD

Thirty-eight asthmatic subjects, occupationally exposed to wheat flour, performed a challenge with lactose then with flour. The instantaneous measurement of the concentration and of the inspiratory airflow were used to calculate the inhaled dose and to establish the dose-response relationships. The results were given 1) by the dose of flour provoking a 20% fall in FEV1 (PDf20), 2) by the comparison of the variation of the FEV1 during the challenge with flour to the distribution of the values observed during the challenge with lactose (inferior limit of the confidence interval at 99.7%).

RESULTS

The variations of the FEV1 were not significantly related to the inhaled dose of lactose. The specific bronchial reactivity to flour was a continuous data and three groups were distinguished: 1) subjects (n = 15) with high bronchial reactivity had a fall of FEV1 of more than 20% 2) subjects (n = 13) without significant variation of the FEV1 for doses higher than 1,400 micrograms by comparison to the distribution of the values of the lactose test 3) subjects (n = 10) with a significant fall of FEV1 by comparison to the distribution of the values of the lactose test but lower than 20%. For this group with moderate reactivity, the flow of the inhaled dose may be determinant for the bronchial response.

CONCLUSIONS

PDf 20 measures the specific bronchial reactivity. However, if the fall in FEV1 is lower than 20%, the specific challenge with flour may be compared to the challenge with lactose to detect the subjects with moderate reactivity. Our results confirmed the role of the inhaled dose and suggested the role of the dose rate in the outset of bronchial obstruction among asthmatic subjects.

Computerized equipment for the delivery of inhaled doses of solid particles in specific bronchial challenge

An apparatus to generate solid particles was tested for use in diagnosing occupational asthma. This equipment measures the inhaled dose of dry particles during specific inhalation challenge. It includes an aerosol generator, a cyclone type particle size selector, and an inhalation chamber to which a patient breathing at tidal volume can be connected for the test. It is fully controlled by a standard personal computer in automatic mode, acting on the flow rate and the aerosol generator to maintain the concentration at a fixed value, usually 3 mg/m3. The dose of aerosol delivered to the patient was calculated from the aerosol concentration, and the inhaled volume was calculated by integration of the corresponding signals. The coefficient of variation for this measurement was estimated to be 12%. The mass median aerodynamic diameter (MMAD) of aerosol inside the inhalation chamber was measured for three substances: lactose, wheat flour, and buckwheat flour. The MMAD of the aerosol inside the chamber was also estimated from the particle size distribution of the raw powder. The relative difference between the measured MMAD and the calculated value was less than 15%. The corresponding relative difference between the measured geometrical SD and the calculated value was found to be less than 26%.

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.

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.

[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.

Increased nitric oxide in exhaled air in patients with systemic sclerosis

OBJECTIVE

To assess the lung production of nitric oxide (NO) in patients with systemic sclerosis.

METHODS

The NO concentration and its rate of production by the lungs were measured in the exhaled air in 14 patients with systemic sclerosis and in 12 healthy control subjects using the chemiluminescent method.

RESULTS

The NO concentration and its rate of production were significantly increased in scleroderma patients (mean +/- SEM, 18.7 +/- 1.7 ppb and 5.8 +/- 0.5 nmol/min, respectively), as compared with control subjects (11.2 +/- 0.8 ppb and 4.3 +/- 0.4 nmol/min, p < 0.01 and p < 0.05, respectively).

CONCLUSION

The pulmonary production of NO is increased in scleroderma patients, which might reflect and contribute to the inflammatory processes of the lungs in systemic sclerosis.

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.

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.

[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.

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.

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.

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.

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.

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.

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.

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)

The arteriovenous fistula in segmental pancreatic transplantation in dogs--a hemodynamic study

Arterial and/or venous thrombosis is a frequent complication in experimental or human pancreatic transplantation. A canine experiment was used to study the hemodynamic effects of spleno-splenic arteriovenous fistula during segmental pancreatic transplantation. An increase in blood flow, without "steal" syndrome in the pancreatic blood supply or pressure increase, was found. Thus this technique can help prevent vascular thrombosis in pancreatic transplant in dogs.

Exercise- and allergen-induced asthma do not change the production of Paf-acether by neutrophils and platelets

Paf-acether, whose role has been suggested in asthma, is a mediator released by stimulated neutrophils, platelets and other cells. Neutrophils and platelets are activated in vivo during exercise or allergen-induced asthma. Upon in vitro stimulation, macrophages from mice treated with an inflammatory stimulus, such as thioglycoccollate, release less paf-acether than macrophages from non-treated mice. We hypothesized that upon in vitro activation platelets and neutrophils should produce less paf-acether after exercise- or allergen-induced asthma. To test this hypothesis, we measured the production of paf-acether by neutrophils and platelets obtained before, 15 and 75 min after exercise in seven normal subjects and five asthmatic subjects with exercise-induced asthma, and in five other asthmatic subjects after specific challenge with Dermatophagoides Pteronyssinus. Purified neutrophils and washed platelets were incubated independently for 10 min at 37 degrees C with no specific activator, with a platelet activator (thrombin, 1 IU.ml-1), a neutrophil activator (opsonized zymosan, 1 mg.ml-1), and both together. We found no significant difference between asthmatic and normal subjects in the amount of paf-acether synthesized by platelets or neutrophils and no fall in the production of paf-acether after exercise- or allergen-induced asthma. However, our method may lack sensitivity in detecting partial activation of these cells and is based on the assumption that changes in peripheral blood cells are representative of changes of these cells in lungs.

Refractoriness after hyperventilation-induced asthma

It is still debated as to whether the bronchospasm induced by hyperpnoea in asthmatic subjects is followed by a period of refractoriness to a subsequent challenge. We studied, therefore, the effect of repeated challenges with eucapnic hyperpnoea in asthmatic subjects and compared it to that in normal subjects. Ten normal and 34 asthmatic subjects were challenged twice with a steady isocapnic hyperventilation (25 l X min-1 X m-2 BSA for 6 min) of dry air at room temperature. The interval between challenges was 30 min in the normal subjects and was 30-60 min in asthmatic subjects to allow for full recovery of FEV1 before the second challenge. In the normal subjects, neither the first nor the second challenge caused a detectable change in FEV1. In the asthmatic subjects, the fall in FEV1 was on average less marked at 5, 8 and 10 min after the second challenge than after the first one (p less than 0.05 by analysis of variance). Analysis of data from individuals showed partial to full refractoriness in 14 of the 34 subjects. In no instance was the fall in FEV1 significantly greater after the second challenge than after the first one. Thirteen other asthmatic subjects were challenged twice at a 30-60 min interval with stepwise increases in ventilation of dry air at room temperature until wheezing or chest tightness occurred or a ventilation of 50 l X min-1 X m-2 BSA was reached.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitative Doppler blood flow measurement method and in vivo calibration

Femoral blood flow (FBF) was measured in seven dogs, simultaneously with both an electromagnetic perivascular probe and a transcutaneous range gated Doppler velocimeter. Measurements were made in basal conditions and during intraarterial infusions of noradrenaline (10 to 400 ng . kg-1 . min-1) and isoprenaline (10 to 400 ng . kg-1 . min-1) thus allowing comparisons of ultrasonic (DBF) and electromagnetic (EMBF) blood flow at 91 different blood flow rates ranging from 5 to 300 cm3 . min-1. The linear regression line through the data of ultrasonic and electromagnetic simultaneous measurement was: DBF = 0.8 + 1.016 EMBF +/- 19.0 cm3 . min-1 with a highly significant correlation (r = 0.96, p less than 0.001) but there was a wide scattering about the mean. Errors in DBF were mainly due to positioning of the probe and determination of arterial diameter.

[Relapsing polychondritis with predominant respiratory involvement treated with Dapsone :value of pulmonary function tests (author's transl)]

A 31-year-old patient had developed lesions in the nasal cartilage during infancy, followed by laryngotracheal lesions when 9 years old. The latter lesions recurred when he was 21, followed several years later by an affection of the main left bronchus and the diagnosis of relapsing polychondritis. Initial respiratory function tests showed mainly a reduction in maximum inspiratory flow, due to sequelae in the upper respiratory tract. Repeated tests were able to demonstrate lesions in the main left bronchus, determining severe expiratory slowing. No significant improvement occurred after one year of corticoïd therapy. Treatment with sulfones (Disulone) produced clinical improvement (reappearance of a vesicular murmur in the left lung) and a twofold increase in FEV1. Functional improvement was even better demonstrated by successive flow-volume curves.