Effects of cigarette smoke on methacholine- and AMP-induced air trapping in asthmatics.

UNLABELLED: Abstract Objective: No information is available on the effect of cigarette smoke on bronchoconstrictor-induced air trapping in asthma. The aim of this study was to evaluate the additional influence of smoking on methacholine- and adenosine 5'-monophosphate (AMP)-induced air trapping in subjects with asthma. METHODS: Airway responsiveness to methacholine and AMP, bronchial (J'awNO) and alveolar (CANO) nitric oxide (NO) and exhaled breath condensate pH were measured in 68 adults (23 current smokers with asthma, 23 non-smokers with asthma and 22 current or former smokers with chronic obstructive pulmonary disease; COPD). The degree of air trapping induced by each bronchoconstrictor agent was expressed by the percent fall in forced vital capacity (FVC) at a 20% fall in forced expiratory volume in 1 s relative to FVC after saline inhalation (ΔFVC%). RESULTS: The ΔFVC% for AMP was higher in both smokers with asthma and patients with COPD than in non-smokers with asthma (p<0.001). By contrast, ΔFVC% for methacholine was similar in the three groups of subjects (p=0.69). In smokers with asthma, but not in the other two groups, there was a correlation between the residual volume/total lung capacity at baseline and the ΔFVC% induced by each bronchoconstrictor agent. Mean values for J'awNO were higher in non-smokers with asthma than in the other two groups (p<0.05). CONCLUSIONS: The results of this study suggest that factors underlying bronchoconstriction induced by indirect agonists are different in smokers and non-smokers with asthma. These observations might be clinically relevant, because triggers that frequently induce bronchial obstruction in the real world act by an indirect mechanism.

Adverse effects of inhaled corticosteroids in funded and nonfunded studies.

BACKGROUND: Evidence regarding the safety profile of drugs may vary depending on study sponsorship. We aimed to evaluate differences between studies funded by the pharmaceutical manufacturer of the drug (PF) and those with no pharmaceutical funding (NoPF) regarding the finding and interpretation of adverse effects of inhaled corticosteroids. METHODS: We assessed the safety reporting of inhaled corticosteroids in 275 PF and 229 NoPF studies identified by a MEDLINE search using prespecified criteria. RESULTS: Overall, the finding of statistically significant differences for adverse effects was significantly less frequent in PF (34.5%) than in NoPF (65.1%) studies (prevalence ratio, 0.53; 95% confidence interval, 0.44-0.64). This association became nonsignificant (prevalence ratio, 0.94; 95% confidence interval, 0.77-1.15) after controlling for design features (such as dose or use of parallel groups) that tended to be associated with less frequent finding of adverse effects and were more common in PF studies. Among studies finding a statistically significant increase in adverse effects associated with the study drug, the authors of PF articles concluded that the drug was "safe" more frequently than the authors of NoPF studies (prevalence ratio, 3.68; 95% confidence interval, 2.14-6.33). CONCLUSIONS: The type of funding may have determinant effects on the design of studies and on the interpretation of findings: funding by the industry is associated with design features less likely to lead to finding statistically significant adverse effects and with a more favorable clinical interpretation of such findings. Disclosure of conflicts of interest should be strengthened for a more balanced opinion on the safety of drugs.

Effect of fluticasone propionate-salmeterol therapy on seasonal changes in airway responsiveness and exhaled nitric oxide levels in patients with pollen-induced asthma.

BACKGROUND: There has been concern that in allergic asthmatic patients there might be an interactive effect on inflammation between regular salmeterol use and exposure to allergens, resulting in increased airway responsiveness. OBJECTIVE: To determine the effects of salmeterol on allergen-induced changes in airway responsiveness and exhaled nitric oxide (ENO) levels in allergic asthmatic patients concomitantly taking inhaled corticosteroids. METHODS: Forty-two asthmatic patients sensitized to pollen allergens were randomly allocated to treatment with fluticasone propionate-salmeterol (n=21) or fluticasone propionate alone (n=21). Spirometry, the methacholine provocation concentration causing a 20% decline in forced expiratory volume in 1 second (PC20), the adenosine 5'-monophosphate (AMP) PC20, and ENO levels were measured before and at the height of the pollen season after 6 weeks of treatment. RESULTS: Changes in the methacholine PC20, the AMP PC20, and ENO levels were not significantly different between treatment groups. No significant changes in the AMP PC20 were observed among the fluticasone propionate-salmeterol and fluticasone propionate groups during natural pollen exposure. However, a significant increase in the methacholine PC20 was observed in the fluticasone propionate-salmeterol group (P = .03) and in the fluticasone propionate group (P = .04); ENO concentrations decreased significantly in both groups during natural allergen exposure (P = .009 and .005). CONCLUSIONS: In patients with pollen-induced asthma, treatment with either fluticasone propionate or fluticasone propionate-salmeterol is associated with significant reductions in methacholine responsiveness and ENO concentrations, even during natural pollen exposure. Furthermore, at least in patients with mild asthma, natural allergen exposure and the regular use of fluticasone propionate-salmeterol are not associated with a greater increase in ENO levels and airway responsiveness than natural allergen exposure and fluticasone propionate use alone.

Influence of the type of operations on the development of latex sensitization in children with myelomeningocele.

BACKGROUND: A genetic tendency to develop latex IgE responses in children with spina bifida has been suggested, but their degree of exposure to latex as well as the route and chronology for sensitization can be different from those of other children with multiple surgeries. The aim was to study the influence of the type of operation on the development of latex sensitization in children with myelomeningocele. METHODS: In 90 children with myelomeningocele operated with latex, data were collected about age, sex, family, and personal history of allergy, serum total IgE, presence of a ventricular-peritoneal (v-p) shunt, and number and duration of operations, classified as urological, orthopedic, on the v-p shunt, other neurosurgical, and others. A multivariate logistic regression analysis was performed, using the presence of latex sensitization as dependent variable. RESULTS: Serum total IgE, the number of urological and of orthopedic operations were synergistic variables to predict latex sensitization, together with the presence of a v-p shunt, but not the number of operations performed on this device. This seems to play an adjuvant role in the process of sensitization. CONCLUSIONS: Not only the number, but also the type of operations, namely, of urological and orthopedic nature, is important in the development of latex sensitization in children with myelomeningocele.

Phenol-containing saline solution as a diluent for adenosine 5'-monophosphate in bronchial challenge testing.

OBJECTIVES: To investigate the effect of dissolving adenosine 5'-monophosphate (AMP) with phenol-containing saline solution on the stability and the bronchoconstrictive properties of this indirect agonist. METHODS: Eleven subjects with asthma well controlled with short-acting inhaled beta2-agonists as required or with inhaled corticosteroids were studied. Bronchial challenge tests with AMP dissolved with either normal saline solution or saline solution containing 0.4% phenol were performed on separate days. Furthermore, to assess the potential influence of the phenol-containing saline solution on the stability of the bronchoconstrictor agent, AMP solutions in concentrations of 40 microg/mL and 400 microg/mL were prepared in saline solution and phenol-containing saline solution and, after 30 min, the AMP levels were determined by high-performance liquid chromatography (HPLC) assay. RESULTS: The geometric mean AMP provocative concentration causing a 20% fall in FEV1 (PC20) was 13.49 mg/mL (95% confidence interval [CI], 6.76 to 26.91) for the saline solution method, and AMP PC20 for the saline solution with phenol method was 8.91 mg/mL (95% CI, 3.39 to 23.44) [p = 0.18]. No significant differences were found between the concentrations of AMP made in saline solution compared to those made in phenol-containing saline solution measured by HPLC. CONCLUSION: These observations indicate that normal saline solution with or without phenol can be used as the diluent for AMP. However, since a potential risk with AMP of industrial sources is the bacterial contamination, adding a preservative such as phenol to a saline solution diluent might be recommended.

Complement component C7 deficiency in two Spanish families.

Different genetic mutations have been described in complement component C7 deficiency, a molecular defect clinically associated with an increased susceptibility to neisserial recurrent infections. In this work we report the genetic basis of C7 deficiency in two different Spanish families (family 1 and family 2). In family 1, of Gypsy ethnical background, exon-specific polymerase chain reaction and sequencing revealed a not previously described single base deletion of nucleotide 1309 (exon 10) in the patient, as well as in her father, leading to a stop codon that causes the premature truncation of the C7 protein (K416 X 419). Additionally, the patient and her mother displayed a missense mutation at position 1135 (exon 9) located in the first nucleotide of the codon GGG (CGG), resulting in a change of amino acid (G357R). This mutation was firstly described in individuals of Moroccan Sephardic Jewish ancestry and has been also reported among Spaniards. In family 2, another novel mutation was found in homozygosity in two siblings; a two base-pair deletion of nucleotides 1922 and 1923 in exon 14 leading to the generation of a downstream stop codon causing the truncation of the C7 protein product (S620 X 630). Our results provide more evidence for the heterogeneous molecular basis of C7 deficiency as well as for the subsequent susceptibility to meningococcal disease, since different families carry different molecular defects. On the other hand, certain C7 defects appear to be prevalent in individuals from certain populations or living in defined geographical areas.

Airway responsiveness to adenosine 5'-monophosphate and exhaled nitric oxide measurements: predictive value as markers for reducing the dose of inhaled corticosteroids in asthmatic subjects.

OBJECTIVES: To investigate the utility of the determination of airway responsiveness to inhaled adenosine 5'-monophosphate (AMP) and exhaled nitric oxide (ENO) levels as markers for safely reducing the dose of inhaled corticosteroids (ICS) in patients with asthma well controlled with a moderately high ICS dose. METHODS: A total of 37 patients with asthma well controlled for at least 3 months by treatment with a moderately high ICS dose (beclomethasone dipropionate, 500 to 1,000 microg or equivalent daily) were included in the study. Patients were treated for a 2-week run-in (baseline) period with their usual dose of ICS. For the next 12 weeks, patients were treated with ICS at half the previous dose, maintaining the same inhalation device. At the end of the baseline period and after 2 weeks, 8 weeks, and 12 weeks of treatment with a reduced dose of ICS, measurements were made in the following order: ENO, spirometry, and AMP challenge. Furthermore, patients completed a diary twice daily recording peak expiratory flow, daytime and nighttime symptoms, and use of rescue albuterol. RESULTS: Ten patients had an asthma exacerbation. Using a Kaplan-Meier survival analysis, the significant predictors of a failure of ICS reduction were having both bronchoconstriction in response to AMP and ENO levels > or = 15 parts per billion (ppb) at baseline (p = 0.006), as well as having both bronchoconstriction in response to AMP and ENO levels > or = 20 ppb at baseline (p = 0.033). Having a decrease in the provocative concentration of AMP causing a 20% fall in FEV(1) of at least one doubling concentration 2 weeks after the dose of ICS was halved was a borderline significant predictor for failure of ICS reduction (p = 0.062). CONCLUSION: These observations suggest that in asthmatic patients well controlled with ICS, the determination of AMP responsiveness and ENO levels may be useful to identifying those subjects whose condition will or will not deteriorate when the dose of ICS is reduced.

Efficacy of latex avoidance for primary prevention of latex sensitization in children with spina bifida.

Over 6 years, the prevalence of latex sensitization fell from 4/15 (26.7%) to 1/22 (4.5%) in children with spina bifida treated in a latex-free environment from birth compared with historic controls. These precautions appear to be efficacious for the primary prevention of latex sensitization.