Relative risks of Internet-related addictions and mood disturbances among college students: a 7-country/region comparison.

OBJECTIVES: This study aimed to determine the relative risks of addiction to the Internet, online gaming and online social networking of college students in six Asian countries/regions (Singapore, Hong Kong [HK]/Macau, China, South Korea, Taiwan and Japan) compared with students in the United States (US). It also explored the relative risks of depression and anxiety symptoms among students with Internet-related addictions from these countries/regions. STUDY DESIGN: This is a cross-sectional survey. METHODS: A convenience sample of 8067 college students aged between 18 and 30 years was recruited from seven countries/regions. Students completed a survey about their use of the Internet, online gaming and online social networking as well as the presence of depression and anxiety symptoms. RESULTS: For all students, the overall prevalence rates were 8.9% for Internet use addiction, 19.0% for online gaming addiction and 33.1% for online social networking addiction. Compared with the US students, Asian students showed higher risks of online social networking addiction but displayed lower risks of online gaming addiction (with the exception of students from HK/Macau). Chinese and Japanese students also showed higher risks of Internet addiction compared with the US students. In general, addicted Asian students were at higher risks of depression than the addicted US students, especially among Asian students who were addicted to online gaming. Addicted Asian students were at lower risks of anxiety than the addicted US students, especially among Asian students who were addicted to online social networking, and addicted students from HK/Macau and Japan were more likely to have higher relative risks of depression. CONCLUSIONS: There are country/regional differences in the risks of Internet-related addictions and psychiatric symptoms. It is suggested that country/region-specific health education programmes regarding Internet-related addictions are warranted to maximise the efficiency of prevention and intervention. These programmes should attempt to tackle not only problematic Internet-related behaviours but also mood disturbances among college students.

Enhanced superconductivity in surface-electron-doped iron pnictide Ba(Fe1.94Co0.06)2As2.

The superconducting transition temperature (TC) in a FeSe monolayer on SrTiO3 is enhanced up to 100 K (refs ,,,). High TC is also found in bulk iron chalcogenides with similar electronic structure to that of monolayer FeSe, which suggests that higher TC may be achieved through electron doping, pushing the Fermi surface (FS) topology towards leaving only electron pockets. Such an observation, however, has been limited to chalcogenides, and is in contrast to the iron pnictides, for which the maximum TC is achieved with both hole and electron pockets forming considerable FS nesting instability. Here, we report angle-resolved photoemission characterization revealing a monotonic increase of TC from 24 to 41.5 K upon surface doping on optimally doped Ba(Fe1-xCox)2As2. The doping changes the overall FS topology towards that of chalcogenides through a rigid downward band shift. Our findings suggest that higher electron doping and concomitant changes in FS topology are favourable conditions for the superconductivity, not only for iron chalcogenides, but also for iron pnictides.

Extracellular vesicles, especially derived from Gram-negative bacteria, in indoor dust induce neutrophilic pulmonary inflammation associated with both Th1 and Th17 cell responses.

BACKGROUND: Many bacterial components in indoor dust can evoke inflammatory pulmonary diseases. Bacteria secrete nanometre-sized vesicles into the extracellular milieu, but it remains to be determined whether bacteria-derived extracellular vesicles in indoor dust are pathophysiologically related to inflammatory pulmonary diseases. OBJECTIVE: To evaluate whether extracellular vesicles (EV) in indoor air are related to the pathogenesis of pulmonary inflammation and/or asthma. METHODS: Indoor dust was collected from a bed mattress in an apartment. EV were prepared by sequential ultrafiltration and ultracentrifugation. Innate and adaptive immune responses were evaluated after airway exposure of EV. RESULTS: Repeated intranasal application of indoor-dust-induced neutrophilic pulmonary inflammation accompanied by lung infiltration of both Th1 and Th17 cells. EV 50-200 nm in diameter were present (102.5 µg protein concentration/g dust) in indoor dust. These vesicles were internalized by airway epithelial cells and alveolar macrophages, and this process was blocked by treatment of polymyxin B (an antagonist of lipopolysaccharide, an outer-membrane component of Gram-negative bacteria). Intranasal application of 0.1 or 1 µg of these vesicles for 4 weeks elicited neutrophilic pulmonary inflammation. This phenotype was accompanied by lung infiltration of both Th1 and Th17 cells, which were reversed by treatment of polymyxin B. Serum dust EV-reactive IgG1 levels were significantly higher in atopic children with asthma than in atopic healthy children and those with rhinitis or dermatitis. CONCLUSION & CLINICAL RELEVANCE: Indoor dust EV, especially derived from Gram-negative bacteria, is a possible causative agent of neutrophilic airway diseases.

Bronchial hyperresponsiveness to methacholine/AMP and the bronchodilator response in asthmatic children.

Bronchodilator response (BDR) is assessed to estimate the reversibility of airflow obstruction. Bronchial hyperresponsiveness (BHR) is a characteristic feature of asthma and is usually measured by means of bronchial challenges using direct or indirect stimuli. The aim of the present study was to compare BHR to methacholine (direct) and that to adenosine 5'-monophosphate (AMP) (indirect) with regard to their relationships to BDR in asthmatic children. Methacholine and AMP challenge tests were performed on 138 children with mild-to-moderate asthma, and the provocative concentration causing a 20% decline in forced expiratory volume in 1 s (FEV1) (PC20) was determined for each challenge. BDR was calculated as the change in FEV(1), expressed as a percentage of the initial value, after inhalation of 400 µg salbutamol. Methacholine PC20 correlated significantly but weakly with BDR (r = -0.254; p = 0.003). However, there was a significant and strong correlation between AMP PC20 and BDR (r = -0.489; p = 0.000). For AMP PC20, the relationship was closer than for methacholine PC20 (p = 0.024 for comparison between correlation coefficients). The same figures were observed when BDR was expressed as a percentage of the predicted value. A stronger correlation of BDR with AMP PC20 than with methacholine PC20 suggests that BDR may be better reflected by BHR as assessed by AMP challenge than by methacholine challenge.

Bronchial hyperresponsiveness to methacholine and adenosine 5'-monophosphate, and the presence and degree of atopy in young children with asthma.

BACKGROUND: Bronchial hyperresponsiveness (BHR) is a characteristic feature of asthma, and is usually measured by bronchial challenges using direct or indirect stimuli. The relationship between atopy and BHR remains to be clarified, particularly in a population selected for asthma. Furthermore, data for young children are limited, although asthma frequently occurs in early childhood. OBJECTIVE: The aim of this study was to investigate methacholine (direct stimulus) and adenosine 5'-monophosphate (AMP) (indirect stimulus) responsiveness according to the presence and degree of atopy in young children with asthma. METHODS: A retrospective analysis of data from 122 preschool children (median age [range]: 5.3 years [4.0-6.8]) presenting with the diagnosis of asthma was performed. These children were characterized by skin-prick tests (SPTs) and bronchial challenges with methacholine and AMP, using a modified auscultation method. The end-point concentration, resulting in audible wheezing and/or oxygen desaturation, was determined for each challenge. Atopy was defined by at least one positive reaction to SPTs, and its degree was assessed using serum total IgE levels, number of positive SPTs, and atopic scores (sum of graded weal size). RESULTS: Atopic patients (n=97) had a significantly lower AMP end-point concentration than non-atopic patients (n=25), whereas the methacholine end-point concentration was not different between the two groups. Among the atopic patients, there was no association between the methacholine end-point concentration and any of the atopy parameters. By contrast, a significant association was found between the AMP end-point concentration and the degree of atopy reflected in serum total IgE and atopic scores (χ² test for trend, P=0.001, 0.003, respectively). CONCLUSION AND CLINICAL RELEVANCE: Young children with atopic asthma had a significantly greater AMP responsiveness than those with non-atopic asthma, whereas methacholine responsiveness was not significantly different between the two groups. The degree of atopy appeared to be an important factor in AMP responsiveness, but not in methacholine responsiveness, and thus might be a marker of airway inflammation in asthma.

Anisotropic Dirac fermions in a Bi square net of SrMnBi2.

We report the observation of highly anisotropic Dirac fermions in a Bi square net of SrMnBi(2), based on a first-principles calculation, angle-resolved photoemission spectroscopy, and quantum oscillations for high-quality single crystals. We found that the Dirac dispersion is generally induced in the (SrBi)(+) layer containing a double-sized Bi square net. In contrast to the commonly observed isotropic Dirac cone, the Dirac cone in SrMnBi(2) is highly anisotropic with a large momentum-dependent disparity of Fermi velocities of ~8. These findings demonstrate that a Bi square net, a common building block of various layered pnictides, provides a new platform that hosts highly anisotropic Dirac fermions.

Effect of inhaled budesonide on bronchial hyperresponsiveness in adolescents with clinical remission of asthma.

STUDY OBJECTIVE: Many children with asthma go into long-term clinical remission at adolescence, but bronchial hyperresponsiveness (BHR) persists in some of these subjects. The regular use of inhaled corticosteroids improves BHR in patients with symptomatic asthma. The aim of this study was to determine whether BHR in adolescents with asthma remission could be reduced by prolonged treatment with inhaled corticosteroids. DESIGN: A randomized, double-blind, placebo-controlled, parallel study. PATIENTS: Thirty-seven adolescents with BHR and long-term remission of their asthma (neither symptoms nor any medication use during the previous 2 years). INTERVENTION: Subjects received inhaled budesonide (two 200-microg puffs bid; budesonide group, n = 19) or identical placebo (placebo group, n = 18) for 9 months. A separate group of patients with symptomatic asthma (symptomatic group, n = 19), using the same regimen of budesonide, was also studied. MEASUREMENTS AND RESULTS: The provocative concentration of methacholine producing a 20% fall in FEV(1) (PC(20)) was measured before and every 3 months during treatment. There was no significant difference among the three groups for the baseline PC(20). In neither the placebo nor the budesonide group did the geometric mean of PC(20) change significantly over the 9-month period. In contrast, a significant increase in PC(20) was noted in the symptomatic group as a result of the budesonide treatment. CONCLUSION: Our data have shown that budesonide inhaled regularly for 9 months did not cause a significant improvement in the BHR of adolescents with long-term asthma remission. This suggests that the mechanism underlying BHR in this clinical setting may be different from that in symptomatic asthma.

The effect of regular salbutamol on lung function and bronchial responsiveness in patients with primary ciliary dyskinesia.

STUDY OBJECTIVE: There is growing evidence that regular beta(2)-agonist use in patients with asthma is associated with decreased airway caliber and increased bronchial responsiveness. The aim of this study was to determine whether regular treatment with beta(2)-agonists induces changes in lung function and bronchial responsiveness in patients with primary ciliary dyskinesia. DESIGN: A randomized, double-blind, placebo-controlled, crossover study. PATIENTS: Nineteen children with primary ciliary dyskinesia. INTERVENTIONS: Subjects received inhaled salbutamol or identical placebo (2 x 100 microg qid) for periods of 6 weeks with a wash-out period of 4 weeks. MEASUREMENTS AND RESULTS: FEV(1) was measured before and 3 weeks and 6 weeks after salbutamol or placebo treatment. High-dose methacholine inhalation tests were performed before and 6 weeks after each treatment. The provocative concentration of methacholine producing a 20% fall in FEV(1) (PC(20)) and maximal airway narrowing (MDeltaFFEV(1)) was measured. No significant change in FEV(1) was observed during the salbutamol or placebo periods. No significant differences in the parameters of bronchial responsiveness (PC(20) and MDeltaFFEV(1)) were noted as the result of either salbutamol or placebo treatment. CONCLUSION: Our data have shown that salbutamol, inhaled regularly for 6 weeks, did not cause either a decline in lung function or an increase in bronchial responsiveness in subjects with primary ciliary dyskinesia.

Bronchiolitis obliterans in the 1990s in Korea and the United States.

STUDY OBJECTIVES: Our current knowledge of pediatric bronchiolitis obliterans (BO) is based largely on a few small series of patients that were reported in the older literature. In these older cases, the mortality rate was high. This study was conducted to investigate the characteristics of pediatric BO cases in two different countries. DESIGN: We extracted specific information regarding predisposing factors, symptoms and signs, diagnostic studies, treatment, and outcome from the medical records of 31 children who received diagnoses of BO at four university medical centers in Korea and the United States in the 1990s. RESULTS: The large number of Asian children reflects a clustering of cases in Korea due to adenovirus and Mycoplasma pneumoniae epidemics. The characteristic diagnostic features of BO were present in 29 of 30 high-resolution CT (HRCT) studies. Seven of nine children who underwent biopsies had histologic confirmations of BO. In two patients whose biopsy results were nondiagnostic, the diagnosis was established by HRCT together with pulmonary function testing results that were consistent with nonreversible small airways obstruction. Fifteen children (48.4%) had evidence of hypoxemia. At present, all but one are alive. Patients with elevated severity-of-illness scores were observed to have increased likelihoods of lung transplantation or death. CONCLUSIONS: We conclude that BO has a good overall prognosis and that the mortality rate has declined over the past decade. This could be related primarily to the use of HRCT for accurate diagnosis and the availability of pediatric lung transplantation. BO cases in Korea were associated with infectious epidemics, whereas those in United States had variable predisposing factors.

Primary small cell bronchogenic carcinoma in a 14-year-old boy.

A 14-year-old Korean boy was admitted with cough, hemoptysis, and fever. A chest X-ray showed a solitary pulmonary mass and pneumonitis. Bronchial biopsy by fiberoptic bronchoscopy revealed a poorly differentiated small cell carcinoma. All of the staging information indicated that the patient had limited disease. During the 7 months following diagnosis, he received adjuvant chemotherapy in conjunction with radiotherapy. The size of the lesion was reduced by almost 50%. Small cell bronchogenic carcinoma has not been reported previously in childhood.

Effects of alpha-toxin of Staphylococcus aureus on the ciliary activity and ultrastructure of human nasal ciliated epithelial cells.

OBJECTIVE: The in vitro effects of staphylococcal alpha-toxin on ciliary activity were investigated at different concentrations and exposure times. STUDY DESIGN: Ciliated epithelial cells of the sphenoid sinus were taken from patients operated on for pituitary tumors. Video-computerized analysis technique and transmission electron microscopy were used to analyze the effects of the toxin on ciliary activity. METHODS: Ciliary beat frequency (CBF) was measured in four different concentrations of alpha-toxin including 0.1, 1, 10, and 50 microg/mL. CBF was measured at 2, 4, 6, 12, 24, and 48 hours after administration of the toxin. To observe reversibility of the reduced ciliary activity, after 24-hour incubation in the media containing 10 microg/mL of alpha-toxin, the media were replaced with alpha-toxin-free media. The tissues were also processed for transmission electron microscopy to observe ultrastructural changes of the epithelial cells. RESULTS: CBF increased significantly at 2-hour incubation and then decreased significantly after 12-hour incubation in 10 microg/mL of alpha-toxin (P< .05, repeated-measures ANOVA). The transmission electron microscopic findings showed mitochondrial swelling and a slight protrusion of the plasma membrane of the cilia. In toxin-free media, loss of ciliary activity was not recovered. CONCLUSIONS: CBF increased at first, but with increasing incubation time ciliary movements decreased gradually and stopped eventually. This loss of CBF may be an irreversible change associated with ultrastructural changes in the mitochondria and the plasma membrane of the cilia.

Regulation of mucociliary motility by nitric oxide and expression of nitric oxide synthase in the human sinus epithelial cells.

OBJECTIVES: This study was performed to investigate the changes in ciliary beat frequency (CBF) after treatment with Larginine in the human sinus mucosa and to determine the distribution of inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) in the healthy sinus mucosa. STUDY DESIGN/METHODS: CBF was measured in the sphenoid sinus mucosa of 12 patients who underwent trans-septal trans-sphenoidal hypophysectomy for the treatment of pituitary gland tumor. CBF was measured over 24 hours in Dulbecco's modified Eagle's medium (DMEM) after treatment with L-arginine, its inactive spatial isomer D-arginine, or an NOS inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME). DMEM without treatment with these materials was used as a control. Other pieces of the mucosa were exposed to L-NAME and its inactive spatial isomer D-NAME after preincubation with L-arginine. The specimens were immunohistochemically stained for iNOS and eNOS. RESULTS: CBF increased 24 hours after treatment with L-arginine as compared with control groups. CBF increased in proportion to the increasing concentrations of L-arginine. There was no significant change after treatment with D-arginine or L-NAME. CBF increased after treatment with L-arginine at 30 minutes and maintained for 24 hours. L-NAME inhibited the increase in CBF by L-arginine, but D-NAME showed no such effect. Immunoreactivity to both iNOS and eNOS was frequently observed in the ciliated epithelial cells and was stronger to eNOS than to iNOS. CONCLUSIONS: From the results of this study it is suggested that nitric oxide (NO) produced by iNOS and eNOS using L-arginine may increase CBF in the healthy sinus mucosa and that NO may have a regulatory function in ciliary motility in the human sinus mucosa.

Hypertonic saline decreases ciliary movement in human nasal epithelium in vitro.

Various saline solution formulae are frequently used in patients with rhinosinusitis. Osmolarity affects ciliary beat frequency (CBF); however, little is known about the effects of saline solutions on ciliary activity of nasal epithelial cells. The aim of this study was to assess whether CBF of normal turbinate mucosa is affected by hypertonic, isotonic, or hypotonic saline solution in vitro and whether histologic changes are associated with the alteration of ciliary movement. We assessed variations of CBF after exposure to 0.06%, 0.12%, 0.9%, 3.0%, or 7.0% saline solutions and histologic changes were examined by transmission electron microscopy. Isotonic and hypotonic solutions produced no ciliary slowing; however, ciliostasis was observed within a few minutes in 3.0% or 7.0% solution. The histologic changes demonstrated that the ciliary slowing might be attributed to epithelial damage by fluid transport toward the surrounding medium. In conclusion, hypertonic saline solutions decrease CBF and disrupt nasal epithelial cells in vitro.

Inflammatory cytokine expression on nasal polyps developed in allergic and infectious rhinitis.

To investigate the expression of cytokine mRNAs in nasal polyps and the role of allergy in the pathogenesis of nasal polyposis, we studied the expression of IL-4, IL-5, and IFN-gamma mRNAs using the RT-PCR and Southern blot. Nasal polyp specimens were obtained from 14 patients with infectious rhinitis and 5 patients with perennial allergic rhinitis. Turbinate mucosa specimens were obtained from 10 patients with allergic rhinitis and from 10 healthy subjects as controls. IL-4, IL-5 and IFN-gamma mRNA were expressed in most specimens of allergic turbinate mucosa. The expression of these cytokines was less frequent in normal healthy turbinate mucosa. The density ratios of IL-4, IL-5 and IFN-gamma to beta-actin were individually determined in both polyp and turbinate tissues. The density ratio for each cytokine was relatively higher in polyp tissues than in healthy turbinate mucosa; however, there was no significant difference in the density ratios determined for polyps associated with allergic rhinitis as compared with polyps associated with infectious rhinitis. These findings indicate that nasal polyposis may differ from allergic rhinitis in the mechanism by which IL-4 and IL-5 are increased. It is concluded that allergy may have an insignificant role in the development of nasal polyps.

Bronchial responsiveness to methacholine and adenosine 5'-monophosphate in young children with asthma: their relationship with blood eosinophils and serum eosinophil cationic protein.

BACKGROUND: Bronchial hyperresponsiveness is a characteristic feature of asthma, and is usually measured by bronchial challenges using direct or indirect stimuli. Blood eosinophil numbers and serum levels of eosinophil cationic protein (ECP) are considered as indirect measures of airway inflammation in asthma. The aim of this study was to investigate whether bronchial responsiveness to adenosine 5'-monophosphate (AMP) is more closely associated with blood eosinophil markers, compared with that to methacholine, in young children with asthma. METHODS: Methacholine and AMP bronchial challenges were performed in 4- to 6-year-old children with asthma (n = 77) and in healthy controls (n = 32), using a modified auscultation method. The end-point was defined as the appearance of wheezing and/or oxygen desaturation. The peripheral blood eosinophil counts and serum ECP concentrations were determined in each subject. RESULTS: A positive response to methacholine (end-point concentration < or =8mg/ml) and to AMP (end-point concentration < or =200 mg/ml) was observed in 74 (96.1%) and 66 asthmatic children (85.7%), respectively. A majority of controls was unresponsive to both challenges. In the asthma group, there was no significant correlation between methacholine end-point concentration and the eosinophil counts (r = -0.111, P = 0.337) or serum ECP levels (r = -0.126, P = 0.274). In contrast, AMP end-point concentration correlated significantly with the eosinophil counts (r = -0.372, P = 0.001) and with serum ECP levels (r = -0.371, P = 0.001). CONCLUSIONS: Our results suggest that bronchial responsiveness to AMP is more closely related to airway inflammation, compared with that to methacholine, and support the potential usefulness of AMP challenges in detecting inflammatory changes in young children with asthma.

Relationships of methacholine and AMP responsiveness with peak expiratory flow variability in children with asthma.

BACKGROUND: Both bronchial responsiveness (BR) and peak expiratory flow (PEF) variability are increased in asthma. PEF variability is presumed to reflect the degree of BR in asthma. BR is commonly assessed by bronchial challenges using direct or indirect stimuli. OBJECTIVE: The aim of this study was to compare methacholine and adenosine 5'-monophosphate (AMP) responsiveness with regard to their relationships with PEF variability in children with asthma. METHODS: Methacholine and AMP challenge tests were performed in 79 children with mild to moderate asthma, and a provocative concentration causing a 20% decline in forced expiratory volume in 1 s (PC(20)) was calculated for each challenge. Subjects recorded PEF each morning and each evening for 14 consecutive days. PEF variability was expressed as amplitude percentage mean (amp%mean; high PEF minus low PEF on each day, expressed as a percentage of their mean, averaged over 14 days), and as the lowest percentage highest (low%high; the lowest PEF expressed as a percentage of the highest PEF recorded over the period). RESULTS: Methacholine PC(20) correlated significantly but weakly with both indices of PEF variability (amp%mean: r=-0.285, P=0.011; low%high: r=0.238, P=0.034). However, there was a significant and strong correlation between AMP PC(20) and both amp%mean (r=-0.583, P=0.000) and low%high (r=0.496, P=0.000). For AMP PC(20), the correlations were stronger than for methacholine PC(20) (comparison of correlation coefficients with amp%mean: P=0.021; with low%high: P=0.063). CONCLUSION: Both methacholine PC(20) and AMP PC(20) correlated significantly with PEF variability. However, the stronger correlations for AMP PC(20) than for methacholine PC(20) suggest that PEF variability may be better reflected by BR assessed by AMP than by methacholine.

Bronchial hyperresponsiveness in young children with allergic rhinitis and its risk factors.

BACKGROUND: Subjects with allergic rhinitis but no clinical evidence of asthma have greater bronchial hyperresponsiveness (BHR), and several factors have been implicated as its determinants. However, studies in young children are lacking. The aims of this study were to evaluate the prevalence of BHR in young children with allergic rhinitis and to investigate its risk factors. METHODS: Methacholine bronchial challenges were performed in 4- to 6-year-old nonasthmatic children with allergic rhinitis (n = 83) and in healthy nonatopic controls (n = 32), using a modified auscultation method. The end-point was defined as the appearance of wheezing and/or oxygen desaturation. Subjects were considered to have BHR when they had end-point concentrations of methacholine

Bronchial responsiveness to methacholine and adenosine 5'-monophosphate in atopic and non-atopic preschool children with recurrent wheezing.

BACKGROUND: It is well known that atopy is a major determinant of bronchial hyper-responsiveness (BHR) in both asymptomatic and asthmatic children. However, the relationship between atopy and BHR has not been well studied in preschool children with wheezing. BHR is usually measured by bronchial challenges using direct and indirect stimuli. OBJECTIVE: The aim of this study was to investigate whether atopic and non-atopic preschool wheezers display similar or different BHR profiles for direct and indirect stimuli. METHODS: Methacholine and adenosine 5'-monophosphate (AMP) bronchial challenges were performed in 4 to 6-year-old children with recurrent wheezing, using a modified auscultation method. The end-point was defined as the appearance of wheezing and/or oxygen desaturation. Atopy was determined to be present when a child had at least one positive reaction to a panel of 13 common airborne allergens in the presence of positive and negative controls. RESULTS: A positive response to methacholine (an end-point concentration < or =8 mg/mL) was observed in 89.3% (50/56) of atopic wheezers and in 83.8% (31/37) of non-atopic wheezers (P=0.44) for the difference. By contrast, the frequency of a positive response to AMP (an end-point concentration < or =200 mg/mL) was significantly higher in the atopic group (47/56, 83.9%) compared with the non-atopic group (12/37, 32.4%; P<0.01). CONCLUSION: While a majority of both atopic and non-atopic preschool wheezers were hyper-responsive to methacholine, atopic subjects were more hyper-responsive to AMP than non-atopic subjects. These findings suggest that atopic and non-atopic wheeze in preschool children are related to distinctive pathophysiologic pathways.

Methacholine and adenosine 5'-monophosphate challenges in children with post-infectious bronchiolitis obliterans.

Airway hyperresponsiveness (AHR) is a characteristic feature of asthma, but is also frequently demonstrated by children and adults with chronic obstructive lung diseases. AHR is usually measured by bronchial challenges using direct or indirect stimuli. The aim of this study was to compare these two types of bronchial challenge in children with post-infectious bronchiolitis obliterans (BO). Methacholine and adenosine 5'-monophosphate (AMP) challenges were used as tools for the evaluation of AHR to direct and indirect stimuli, respectively, in children with post-infectious BO (n = 28). These results were compared with those of asthmatic (n = 30) and control children (n = 25). Altogether, twenty-two patients (78.6%) with post-infectious BO were hyperreactive to methacholine with a provocative concentration causing a 20% fall in forced expiratory volume in one second (PC20) of <16 mg x mL(-1), but only six (21.4%) were hyperreactive to AMP with a PC20 of <200 mg x mL(-1). All patients with asthma responded positively to methacholine, and most (28, 93.3%) also responded positively to AMP. The majority of controls were insensitive to both challenges. Airway hyperresponsiveness to methacholine is a frequent, but by no means universal, finding in children with post-infectious bronchiolitis obliterans, but is usually not accompanied by airway hyperresponsiveness to adenosine 5'-monophosphate. This finding suggests that airway hyperresponsiveness in patients with post-infectious bronchiolitis obliterans has characteristics that differ from those of asthmatic subjects.

Coincidence of atopy profile in terms of monosensitization and polysensitization in children and their parents.

BACKGROUND: Results from epidemiologic studies have shown that childhood atopy is probably a hereditary disorder, because the offspring of affected parents have a higher risk of developing atopy. Among the atopic population, some subjects are sensitized to only one class of allergens (monosensitized), while other subjects are sensitized to more than one class of allergens (polysensitized). The aim of this study was to investigate whether atopy profile (monosensitization/polysensitization) in children is linked to the same conditions in their parents. METHODS: We evaluated sensitization to five classes of aeroallergens (house dust mites, animal danders, pollens, molds, and cockroach) by skin prick testing in a group of 494 children with suspicious allergic symptoms and in their parents. RESULTS: The frequency of parental atopy was highest (51.6%) in polysensitized children (n = 189), intermediate (37.1%) in monosensitized children (n = 178), and was lowest (22.4%) in nonsensitized children (n = 127). The proportion of polysensitized subjects among atopic parents was significantly higher for polysensitized children (45.6%) than for monosensitized children (31.1%). Polysensitized children were found to more frequently have one or both parents polysensitized (32.3%, 7.4%) than monosensitized children (18.5%, 2.2%) with odds ratios of 2.09 (95% CI: 1.29-3.40) and 3.48 (1.12-10.78), respectively, whereas the likelihood of having one or two monosensitized parents was not increased for polysensitized children. CONCLUSION: Our data suggest a familial coincidence of atopy profile in terms of monosensitization and polysensitization, although the relative importance of genetic or environmental influence should be studied further.