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793 Adenosine, exercise and fog bronchin challenges in asthmatic children
338
795
793
-Bronchial challenges (BC)in adults with adenosine (SAMP), exercise (E), ultrasonically distilled water (F) share a common feature which is a refractory period suggesting possible common pathogenic pathways. We have previously shown that grossly only 25% of stable asthmatic children exhibit positive FBC, while all of them react to 5AMPBC. We thus compared these 3 different BC in 12 perfectly stable asthmatic children (11.8+3.2 years) who only required cromolyn as prolonged treatment and occasionally beta2mimetics (BZ).The 3 days prior to entering the study, their FEVl values without 82 were in the normal range at 8 am, and the variations of FEVI values between 8am and 8 pm did not exceed 10%. The 3 BC were performed on 3 separate days at least 3 days apart but without exceeding 5 days. Cromolyn was witheld 48 and 82 12 hours before entering the study.BC protocoles were performed according to designs in the literature (cycloergometer for EBC).Bronchial patency was assessed by frequency oscillation airway resistances. The test was considered positive (P)if resistances were doubled, doubtful (0) if increased of 40% or more and negative (N).The results are summarized below: D P 1 EBC 9" 10 1 : FBC 5AMPBC 0 0 12 In perfectly stable asthmatic children, EBC (indoor) and FBC are usually negative while 5AMPBC are positive.
784
J. ALLERGY
Abstracts
BARLYAWLATERBWMONINA~~TION amPARIsQ4 UF ?w WAYS TEsT(m)wITHm: OF W EXKSURE. J.B. Wassarfaflen I'D, P. em, A. I&Xd~,Lausanne, Switzerland. In order to ampare the intensity of both the early and late allergic reaction (EAR an3 I-AH) induced by a stepwise versus a single administraticn of an allergen, 15 asthmatic patients (p) uxkrwent 2 BET separated by 14 days: the first WC (ETl)waspe3zformedwithincredsingdoses of allergen (cat in 11 p and house dust mite in 4 p; AIX extracts, 100 to 100'000 SQ) and the doseprogressionwas stoppedwhena 20%dropin LEVI was obtained (reaction threshold). Only p with L&H (definedby atleasta15% drop in ETWl) were considered. At the second BP'?., the p were exposed to the sit@e allergen dose correspondimg to the highestreach&i in BETl. If this did not induce a 20% drop in FEVT, the nextincrementaldosewas administered. The reaction threshold was identical in 11/15 p, tiereas4pneadedanadditionnaldose.Meanmw: drop (+ SDl) in FBVI during EAR was 34% + 11 in BPTI &l 39% + 11 in BI?J!2, respectively 25% f: 10 and26%+12&rint~IAR. Inthe4pwhoneeded anaddit&nal&, br0nCbial&truoti0nWaS more Rronrxlnced during EAR (p
CLIN. iMMUNCh. JANUARY ‘991
FACTORSAFFECTINGTHE DISCRIMINANTABILITY OF PROVOCATION DOSES TO HISTAMINE. Valentin Pooa. M.D., Sacramento, CA In a previous paper (Chest, 94:466) we have studied the discriminant ability of 6 provocation doses (PD) to histamine (H): PDIO, PDl3, PDzD, PDIoT, PDzDC, PD40. The subscript connotes -%ASGaw(PD40), -%AFEVl>lO%(PDIOT), -%A measured with the lowest FEVI (PD2OCj or thebest FEVl (PDIO. PDI3). To explain the discriminant ability (PD2O=PDI5>PDIOT=PD4O>PD2OC>PDIDj, this study analyzed the role of "an/variability, slope of log dose-response curve (LDRC) and the test itself in the original group of 20 normal (N) For PD measured and 20 asthmatic (A) subjects. with the best FEVI, the discriminant ability paralleled the value of %A/variabiIity and the frequency of PD location on the steep portion of LDRC. For PD based on best FEVI or SGaw, %A/ variability and LDRCwere similar in N and A. The lower discriminant ability of PD40 than PD2D or PDI5 did not depend of %A/variabiIity (3.7, 3.5, 4.0, respectively) or steepness of LDRC: %A/log dose H was 72 (A) and 63 (Ni vs. 42 (A) and 40 (N) for SGaw or best FEVI, respectively. The low discriminant ability of PD2DCwas not related to %A/variability (3.7) or steepness of LDRCbut to their high rate of false positive results (13/20 for PD2OCvs. 5/20 for PI)20 or 6/20 for PD40). In conclusion, the discriminant ability of PD depends on: 1) %A/variabiIity and location on steep LDRCfor PD based on best FBVI. 2) The respiratory manoever for PD2OC;successive inhalations increase the initial PEVI much more in N than in A, reducing for PD based on best FEVI the proportion of N with A PD. 3'1 The nature of the test for SGaw.
SALINE DOES
AND ONE
EXERGISE INDUCE
Patients with EIA, who exercise to the point of bronchospaem, are often refractory to further EIA for a period of a few hour-a after the inibal stimulus. We undertook this study to inves@ate whether exercise chetlenge induces a refrac#y period to hyperoqolar saline chatkqe, or vice versa. Demonstration of such a refractory period would be evidenceforasimilarmechanismofaction.
Eleven patients with documented asthma underwent a standaMized treadmill exercise test, and then a hyperosmokr saline chat&f&&? 1 hour later. The same patients returned l-19 days later for the same tests, in reverse order.
exercise afterwards. These results indiie that hyperosmoiar saline and exercise chatienge induce mutual refractoriness in approximate1 l/2 the patients, suppoiting a hypothesis oy sin-&r mechanisms of action.
795
793
-Bronchial challenges (BC)in adults with adenosine (SAMP), exercise (E), ultrasonically distilled water (F) share a common feature which is a refractory period suggesting possible common pathogenic pathways. We have previously shown that grossly only 25% of stable asthmatic children exhibit positive FBC, while all of them react to 5AMPBC. We thus compared these 3 different BC in 12 perfectly stable asthmatic children (11.8+3.2 years) who only required cromolyn as prolonged treatment and occasionally beta2mimetics (BZ).The 3 days prior to entering the study, their FEVl values without 82 were in the normal range at 8 am, and the variations of FEVI values between 8am and 8 pm did not exceed 10%. The 3 BC were performed on 3 separate days at least 3 days apart but without exceeding 5 days. Cromolyn was witheld 48 and 82 12 hours before entering the study.BC protocoles were performed according to designs in the literature (cycloergometer for EBC).Bronchial patency was assessed by frequency oscillation airway resistances. The test was considered positive (P)if resistances were doubled, doubtful (0) if increased of 40% or more and negative (N).The results are summarized below: D P 1 EBC 9" 10 1 : FBC 5AMPBC 0 0 12 In perfectly stable asthmatic children, EBC (indoor) and FBC are usually negative while 5AMPBC are positive.
784
J. ALLERGY
Abstracts
BARLYAWLATERBWMONINA~~TION amPARIsQ4 UF ?w WAYS TEsT(m)wITHm: OF W EXKSURE. J.B. Wassarfaflen I'D, P. em, A. I&Xd~,Lausanne, Switzerland. In order to ampare the intensity of both the early and late allergic reaction (EAR an3 I-AH) induced by a stepwise versus a single administraticn of an allergen, 15 asthmatic patients (p) uxkrwent 2 BET separated by 14 days: the first WC (ETl)waspe3zformedwithincredsingdoses of allergen (cat in 11 p and house dust mite in 4 p; AIX extracts, 100 to 100'000 SQ) and the doseprogressionwas stoppedwhena 20%dropin LEVI was obtained (reaction threshold). Only p with L&H (definedby atleasta15% drop in ETWl) were considered. At the second BP'?., the p were exposed to the sit@e allergen dose correspondimg to the highestreach&i in BETl. If this did not induce a 20% drop in FEVT, the nextincrementaldosewas administered. The reaction threshold was identical in 11/15 p, tiereas4pneadedanadditionnaldose.Meanmw: drop (+ SDl) in FBVI during EAR was 34% + 11 in BPTI &l 39% + 11 in BI?J!2, respectively 25% f: 10 and26%+12&rint~IAR. Inthe4pwhoneeded anaddit&nal&, br0nCbial&truoti0nWaS more Rronrxlnced during EAR (p
CLIN. iMMUNCh. JANUARY ‘991
FACTORSAFFECTINGTHE DISCRIMINANTABILITY OF PROVOCATION DOSES TO HISTAMINE. Valentin Pooa. M.D., Sacramento, CA In a previous paper (Chest, 94:466) we have studied the discriminant ability of 6 provocation doses (PD) to histamine (H): PDIO, PDl3, PDzD, PDIoT, PDzDC, PD40. The subscript connotes -%ASGaw(PD40), -%AFEVl>lO%(PDIOT), -%A measured with the lowest FEVI (PD2OCj or thebest FEVl (PDIO. PDI3). To explain the discriminant ability (PD2O=PDI5>PDIOT=PD4O>PD2OC>PDIDj, this study analyzed the role of "an/variability, slope of log dose-response curve (LDRC) and the test itself in the original group of 20 normal (N) For PD measured and 20 asthmatic (A) subjects. with the best FEVI, the discriminant ability paralleled the value of %A/variabiIity and the frequency of PD location on the steep portion of LDRC. For PD based on best FEVI or SGaw, %A/ variability and LDRCwere similar in N and A. The lower discriminant ability of PD40 than PD2D or PDI5 did not depend of %A/variabiIity (3.7, 3.5, 4.0, respectively) or steepness of LDRC: %A/log dose H was 72 (A) and 63 (Ni vs. 42 (A) and 40 (N) for SGaw or best FEVI, respectively. The low discriminant ability of PD2DCwas not related to %A/variability (3.7) or steepness of LDRCbut to their high rate of false positive results (13/20 for PD2OCvs. 5/20 for PI)20 or 6/20 for PD40). In conclusion, the discriminant ability of PD depends on: 1) %A/variabiIity and location on steep LDRCfor PD based on best FBVI. 2) The respiratory manoever for PD2OC;successive inhalations increase the initial PEVI much more in N than in A, reducing for PD based on best FEVI the proportion of N with A PD. 3'1 The nature of the test for SGaw.
SALINE DOES
AND ONE
EXERGISE INDUCE
Patients with EIA, who exercise to the point of bronchospaem, are often refractory to further EIA for a period of a few hour-a after the inibal stimulus. We undertook this study to inves@ate whether exercise chetlenge induces a refrac#y period to hyperoqolar saline chatkqe, or vice versa. Demonstration of such a refractory period would be evidenceforasimilarmechanismofaction.
Eleven patients with documented asthma underwent a standaMized treadmill exercise test, and then a hyperosmokr saline chat&f&&? 1 hour later. The same patients returned l-19 days later for the same tests, in reverse order.
exercise afterwards. These results indiie that hyperosmoiar saline and exercise chatienge induce mutual refractoriness in approximate1 l/2 the patients, suppoiting a hypothesis oy sin-&r mechanisms of action.