bluuebunny/crossref_metadata_2025_split huggingface dataset:
CLUSTERING PANEL DATA VIA PERTURBED ADAPTIVE SIMULATED ANNEALING AND GENETIC ALGORITHMS
Authors: BONZO DANIEL C. , HERMOSILLA AUGUSTO Y. 
Published: January 2003

Non-hierarchical cluster analysis for panel data is known to be hampered by structural preservation, computational complexity and efficiency, and dependency problems. Resolving these issues becomes increasingly important as efficient collection and maintenance of panel data make application more conducive.To address some computational issues and structural preservation, Bonzo [3] presented a stochastic version of Kosmelj and Batagelj's approach [16] to clustering panel data. The method used a probability link function (instead of the usual distance functions) in defining cluster inertias with the aim of preserving the clusters' probabilistic structure. Formulating clustering as an optimization problem, the objective function allows the application of heuristic and stochastic optimization techniques.In this paper, we present a modified heuristic for adaptive simulated annealing (ASA) by perturbing the state vector's sampling distribution, specifically, by perturbing the drift of a diffusion process. Such an approach has been used to hasten convergence towards global optimum at equilibrium for diversely complex, combinatorial, and large-scale systems. The perturbed ASA (PASA) heuristic is then embedded in a genetic algorithm (GA) procedure to hasten and improve the stochastic local search process. The PASA-GA hybrid can be further modified and improved such as by explicit parallel implementation.
Urinary leukotriene E4in preschool children with acute clinical viral wheeze
Authors: Oommen A. , Grigg J. 
Published: January 2003

Cysteinyl leukotrienes (cystLTs) are important mediators of wheeze in atopic asthma, but the role of cystLTs in the pathogenesis of preschool viral wheeze (PVW) is unclear. Therefore, evidence for increased production of cystLTs in PVW was sought.Urinary leukotriene E4(uLTE4) and serum total immunoglobulin (Ig)E were measured in children (1–5 yrs) with PVW during an acute attack (n=44) and in the convalescent phase (n=19), and compared with normal controls (n=15). The effect of atopic sensitisation was assessed in a separate group of atopic controls (n=6) in whom only uLTE4was measured.The levels of uLTE4were similar in normal and atopic controls and increased in acute PVW (median (interquartile range) 165 (101–285)versus125 (82–163) ng·mM creatinine−1). Stratification by IgE showed that whereas uLTE4was increased in 23 children with acute PVW and IgE >95th percentile (median 211 (118–312) ng·mM creatinine−1), uLTE4was not increased in the 21 children with acute PVW and IgE ≤95th percentile. In the convalescent phase, uLTE4fell in the subgroup with high IgE but not in the subgroup with low IgE.It is concluded that increased cysteinyl leukotriene production during acute preschool viral wheeze is associated with high serum immunoglobulin E.
Effect of oxygen on breath markers of oxidative stress
Authors: Phillips M. , Cataneo R.N. , Greenberg J. , Grodman R. , Gunawardena R. , Naidu A. 
Published: January 2003

Supplemental oxygen is often administered to induce hyperoxia in nonhypoxic patients for indications such as chest pain, despite lack of evidence of clinical benefit. Induced hyperoxia is potentially toxic, since it may increase oxidative stress and peroxidative damage to deoxyribonucleic acid, lipids and proteins.The aim of this study was to establish whether supplemental oxygen induces oxidative stress in nonhypoxic subjects.Breath markers of oxidative stress were measured in 31 healthy subjects before and after breathing 28% oxygen at 2.0 L·min−1vianasal prongs for 30 min while resting. The criterion standard of oxidative stress was the breath methylated alkane contour (BMAC), a three-dimensional plot of the alveolar gradients of C4–C20 alkanes and monomethylated alkanes produced by lipid peroxidation. Volatile organic compounds (VOCs) in breath were assayed by gas chromatography and mass spectroscopy, and the BMACs before and after oxygenation were compared.Following oxygenation, there was a significant increase in mean volume under the curve of the BMAC and in alveolar gradients of three VOCs: 3‐methyltridecane, 3‐methylundecane and 5-methylnonane.Breath markers of oxidative stress were significantly increased in normal volunteers breathing supplemental oxygen for 30 min.
Socioeconomical conditions as risk factors for bronchial asthma in children aged 4–5 yrs
Authors: Lindbæk M. , Wefring K.W. , Grangård E.H. , Øvsthus K. 
Published: January 2003

A number of factors are associated with the development of childhood asthma. The purpose of this study was to establish the prevalence of childhood asthma and to explore the socioeconomic background factors associated with childhood asthma in a Norwegian cohort of children aged 4–5 yrs.A questionnaire was given to parents in connection with the ordinary child control of 4–5‐yr-old children in Vestfold county, Norway. In addition to the question “Has the child at present or ever had asthma?”, a number of medical and socioeconomical background factors were registered.Of the 2,430 parents, 1,913 (79%) responded. Of the 163 (cumulative prevalence 8.7%) children with confirmed asthma, 19 did not use any medication and were regarded as having outgrown their asthma. Several background factors were significantly associated with asthma in a logistic regression analysis: few rooms at home, psychosocial problems, fever more than three times during the last year, hay fever, reaction to food and mother or father with chronic disease.The findings indicate that socioeconomic background factors are associated with asthma in childhood, in addition to other known risk factors.
Modulatory role of tachykinin NK1receptor in cholinergic contraction of mouse trachea
Authors: Tournoy K.G. , De Swert K.O. , Leclere P.G. , Lefebvre R.A. , Pauwels R.A. , Joos G.F. 
Published: January 2003

The role of the NK1receptor in airway contraction induced by electrical field stimulation (EFS) was evaluated by comparing the response in NK1receptor knockout mice (NK1R−/−) with that of NK1receptor wild-type controls (WT).A frequency/response curve on tracheas from NK1R−/−mice and NK1R WT littermates was constructed. After incubation with [3H]choline, [3H]acetylcholine release upon EFS was measured by high-performance liquid chromatography and liquid scintillation counting. The effects of atropine (1×10−6 M), tetrodotoxin (1×10−6 M) and a specific NK1R antagonist (SR140333, 1×10−8 M) were studied, as well as the effects of substance P (1×10−5 M) on precontracted tracheas.Upon EFS, NK1R−/−mice had a significant lower trachea contractility than the NK1R WT animals, accompanied with less [3H]acetylcholine release. Pretreatment with atropine or tetrodotoxin abolished the EFS-induced contraction in both strains. Pretreatment with the NK1R antagonist SR140333 significantly reduced the contractility in the NK1R WT but not in the NK1R−/−mice. Substance P caused a small contraction in both NK1R WT and NK1R−/−mice. Substance P induced a relaxation in precontracted tracheas in NK1R WT but not in NK1R−/−mice.The data presented here provide direct evidence that the NK1receptor augments cholinergic neurotransmission in mouse trachea.
Disease severity and the effect of fluticasone propionate on chronic obstructive pulmonary disease exacerbations
Authors: Jones P.W. , Willits L.R. , Burge P.S. , Calverley P.M.A. 
Published: January 2003

Exacerbations of chronic obstructive pulmonary disease (COPD) are associated with worse health and increased healthcare utilisation. The Inhaled Steroids in Obstructive Lung Disease in Europe (ISOLDE) study in COPD showed a 26% reduction in the yearly rate of exacerbations in patients treated with fluticasone propionate (FP) compared to placebo, but did not indicate which patients showed greatest benefit.In this study the patients were stratified into mild and moderate‐to‐severe COPD using the American Thoracic Society criterion of forced expiratory volume in one second (FEV1) 50% predicted, and the total number of exacerbations and those requiring treatment with oral corticosteroids were examined.There were 391 (195 FP) patients with mild COPD and 359 (180 FP) patients with moderate‐to‐severe disease. The exacerbation rate was highly skewed in mild disease, but more normally distributed in moderate‐to‐severe disease. FP reduced the overall exacerbation rate in moderate‐to‐severe disease (FP median rate 1.47 yr−1, placebo 1.75 yr−1), but not in mild disease (FP 0.67 yr−1, placebo 0.92 yr−1). FP use was associated with fewer patients with ≥1 exacerbation·yr−1being treated with oral corticosteroids (mild: FP 8%, placebo 16%; moderate‐to‐severe: FP 17%, placebo 30%).Effects of fluticasone propionate on exacerbations were seen predominantly in patients with a postbronchodilator forced expiratory volume in one second <50% predicted. These data support recommendations in the Global Initiative for Chronic Obstructive Disease treatment guidelines that inhaled corticosteroids should be considered in patients with moderate‐to‐severe chronic obstructive pulmonary disease who experience recurrent exacerbations.
Home hospitalisation of exacerbated chronic obstructive pulmonary disease patients
Authors: Hernandez C. , Casas A. , Escarrabill J. , Alonso J. , Puig-Junoy J. , Farrero E. , Vilagut G. , Collvinent B. , Rodriguez-Roisin R. , Roca J. ,   and partners of the CHRONIC project
Published: January 2003

It was postulated that home hospitalisation (HH) of selected chronic obstructive pulmonary disease (COPD) exacerbations admitted at the emergency room (ER) could facilitate a better outcome than conventional hospitalisation.To this end, 222 COPD patients (3.2% female; 71±10 yrs (mean±sd)) were randomly assigned to HH (n=121) or conventional care (n=101). During HH, integrated care was delivered by a specialised nurse with the patient's free-phone access to the nurse ensured for an 8‐week follow-up period.Mortality (HH: 4.1%; controls: 6.9%) and hospital readmissions (HH: 0.24±0.57; controls: 0.38±0.70) were similar in both groups. However, at the end of the follow-up period, HH patients showed: 1) a lower rate of ER visits (0.13±0.43versus0.31±0.62); and 2) a noticeable improvement of quality of life (Δ St George's Respiratory Questionnaire (SGRQ), −6.9versus−2.4). Furthermore, a higher percentage of patients had a better knowledge of the disease (58%versus27%), a better self-management of their condition (81%versus48%), and the patient's satisfaction was greater. The average overall direct cost per HH patient was 62% of the costs of conventional care, essentially due to fewer days of inpatient hospitalisation (1.7±2.3versus4.2±4.1 days).A comprehensive home care intervention in selected chronic obstructive pulmonary disease exacerbations appears as cost effective. The home hospitalisation intervention generates better outcomes at lower costs than conventional care.
Systematic assessment of difficult-to-treat asthma
Authors: Robinson D.S. , Campbell D.A. , Durham S.R. , Pfeffer J. , Barnes P.J. , Chung K.F. 
Published: January 2003

Five per cent of asthmatics remain symptomatic despite high-dose treatment. The aim of the study was to investigate how often such difficult-to-treat asthma is due to intractable asthma, misdiagnosis, non-adherence with therapy, or psychiatric problems.Difficult asthma was defined as persistence of symptoms despite treatment at step 4 of British guidelines or requirement for long-term oral glucocorticoids (step 5). One-hundred patients with a respiratory physician diagnosis of asthma were investigated in a single tertiary respiratory unit in an open and descriptive study.Twelve of the patients studied did not have asthma and a further seven had additional diagnoses. Of the remainder, 55 had an asthma diagnosis confirmed by demonstration of reversible airflow narrowing or peak flow variability, whilst 20 did not. Noncompliance with prednisolone therapy was more frequent in the 55 with confirmed asthma (nine of 18 prescribed oral prednisolone at a dose of ≥15 mg·day−1) and was not detected in the “unconfirmed asthma” group. There were no other significant differences between these groups. A major psychiatric component was detected in 10 patients.Systematic evaluation of difficult asthma is useful as it can identify alternative or additional diagnoses, psychiatric illness or nonconcordance with therapy in a substantial proportion of cases (32% in the present series).
The role of concomitant respiratory diseases on the rate of decline in FEV1among adult asthmatics
Authors: Sherrill D. , Guerra S. , Bobadilla A. , Barbee R. 
Published: January 2003

Several recent reports have presented evidence suggesting that adults with asthma have an accelerated rate of decline in pulmonary function compared with nonasthmatics. However, most of these studies have not taken into account the possible effect of comorbid lung disease in addition to asthma. This study was designed to determine if comorbid respiratory diseases modify or otherwise change the estimates of decline in forced expiratory volume in one second (FEV1).Study subjects were White, non-Mexican, American participants, who were ≥20 yrs of age at the initial survey and had at least one pulmonary function testing. Respiratory disease status, based on self-reported questionnaires and pulmonary function tests, were assessed during 12 surveys spanning a period of up to 20 yrs.There were 2,926 subjects who met the inclusion criteria, 214 (7.3%) had physician-confirmed asthma, 325 (11.1%) chronic obstructive pulmonary disease (COPD), and 125 (4.3%) both physician-confirmed asthma and COPD. Longitudinal analysis revealed that among those with longstanding asthma, FEV1values were low but did not decline at a more rapid rate than normal. Likewise, subjects with both asthma and COPD had the lowest levels of FEV1, but also a rate of decline that was not significantly increased. Only those with COPD in the absence of asthma experienced both a low initial FEV1level and a significantly steeper rate of decline.Based on these findings, the authors conclude that forced expiratory volume in one second does not decline more rapidly in asthmatics or in those with asthma and chronic obstructive pulmonary disease, compared with nonasthmatics.
Cost of illness of atopic asthma and seasonal allergic rhinitis in Germany: 1‐yr retrospective study
Authors: Schramm B. , Ehlken B. , Smala A. , Quednau K. , Berger K. , Nowak D. 
Published: January 2003

The purpose of this study was to evaluate the cost of illness of moderate-to-severe atopic asthma and/or seasonal allergic rhinitis (SAR) in Germany from the perspective of third-party payers (TPP) and patients.Five-hundred patients (276 children/adolescents) with moderate-to-severe asthma and/or SAR were included in this cross-sectional study. Information was collected using a specific patient questionnaire and the abstraction of patient records.Overall, annual costs per patient increased with the severity of atopic asthma and if it was associated with SAR. The average annual cost of SAR was 1,089 per child/adolescent and 1,543 per adult. Annual costs of severe asthma plus SAR increased to 7,928 per child/adolescent and to 9,287 per adult. For TPPs, the main cost drivers were medication, hospitalisation, and rehabilitation. The most significant costs for patients were household modifications. For children/adolescents, 60–78% of the expenditures were direct costs, while in adults, 58% of expenditures were indirect costs. It was also observed that patients with moderate and severe asthma used inhaled corticosteroids less frequently than recommended by treatment guidelines.In summary, the total cost for patients increases with the severity of atopic asthma and/or seasonal allergic rhinitis and indirect costs represent a large proportion of the total cost.
Effect of inhaled bronchodilators on inspiratory capacity and dyspnoea at rest in COPD
Authors: Di Marco F. , Milic-Emili J. , Boveri B. , Carlucci P. , Santus P. , Casanova F. , Cazzola M. , Centanni S. 
Published: January 2003

It has been shown that patients with chronic obstructive pulmonary disease (COPD) develop dynamic hyperinflation (DH), which contributes to dyspnoea and exercise intolerance. Formoterol, salmeterol and oxitropium have been recommended for maintenance therapy in COPD patients, but their effect on DH has only been assessed for salmeterol.The aim of the present study was to compare the acute effect of four inhaled bronchodilators (salbutamol, formoterol, salmeterol and oxitropium) and placebo on forced expiratory volume in one second, inspiratory capacity, forced vital capacity and dyspnoea in COPD patients. A cross-over, randomised, double-blind, placebo-controlled study was carried out on 20 COPD patients.Patients underwent pulmonary function testing and dyspnoea evaluation, in basal condition and 5, 15, 30, 60 and 120 min after bronchodilator or placebo administration.The results indicate that in chronic obstructive pulmonary disease patients with decreased baseline inspiratory capacity, there was a much greater increase of inspiratory capacity after bronchodilator administration, which correlated closely with the improvement of dyspnoea sensation at rest. For all bronchodilators used, inspiratory capacity reversibility should be tested at 30 min following the bronchodilator. On average, formoterol elicited the greatest increase in inspiratory capacity than the other bronchodilators used, though the difference was significant only with salmeterol and oxitropium. The potential advantage of formoterol needs to be tested in a larger patient population.
Epoprostenol therapy for primary pulmonary hypertension after rejection of a single donor lung
Authors: Roeleveld R.J. , Vonk Noordegraaf A. , van der Bij W. , Postmus P.E. , Boonstra A. 
Published: January 2003

Before prostacyclins became available, lung or heart/lung transplantation was the only effective treatment for patients with primary pulmonary hypertension (PPH) who deteriorated under supportive medical treatment. Unfortunately, acute and chronic rejections occur in a large number of cases, limiting the average survival to 4.5 yrs.A female patient, age 35 yrs, was diagnosed with PPH and underwent single lung transplantation. Despite aggressive immunosuppressive therapy, the patient had several episodes of acute rejection. Eventually, chronic rejection with bronchiolitis obliterans developed. After 5 yrs, the donor lung was no longer functional. The patient was in New York Heart Association (NYHA) class 4, had a 6‐min walking distance of 50 m and a resting arterial oxygen tension (Pa,O2) of 9.8 kPa (74 mmHg) when using 3 L·min−1of oxygen.Epoprostenol treatment was started and the patient showed remarkable improvement. After 17 months the patient was NYHA class 2, walked 503 m in 6 min and had a restingPa,O2of 10.9 kPa (82 mmHg) without supplemental oxygen.In this patient, treatment with epoprostenol was effective after rejection of a single donor lung transplanted for primary pulmonary hypertension.
Stretch-induced changes in constricted lung parenchymal strips: role of extracellular matrix
Authors: Salerno F.G. , Fust A. , Ludwig M.S. 
Published: January 2003

Large amplitude oscillations of contracted airway smooth muscle cause relative relaxation of the preparation. However, little is known about the effect of mechanical stretch on distal lung behaviour.Rat parenchymal strips were suspended in an organ bath and attached at one end to a force transducer and at the other end to a servo-controlled lever arm that effected length changes. Mechanical impedance of the strip was measured by applying a complex signal consisting of pseudorandom length oscillations of varying frequencies (0.5–19.75 Hz). A constant phase model was fit to changes in length and tension to calculate tissue damping (G) and elastance (H). Hysteresivity was calculated as G/H. Impedance was measured before and after sinusoidal length oscillation at different amplitudes (1, 3, 10 and 25% of resting length) at a frequency of 1 Hz under baseline conditions and after acetylcholine-induced constriction.Oscillations of 10 and 25% amplitudes significantly decreased the G and H of the lung strip. The effect of length oscillations was no different in controlversusconstricted strips.These data suggest that in the distal lung, large stretches affect the structural components of the extracellular matrix rather than the contractile elements.
Airway surface pH in subjects with cystic fibrosis
Authors: McShane D. , Davies J.C. , Davies M.G. , Bush A. , Geddes D.M. , Alton E.W.F.W. 
Published: January 2003

The cystic fibrosis (CF) transmembrane conductance regulator protein can transport bicarbonate and may therefore regulate airway surface (AS) pH. Disturbances of AS pH could contribute to the pathophysiology of CF lung disease.Five studies were carried out including the following: study 1) nasal pH measurements were made in 25 CF and 10 non-CF adults using an antimony pH probe. Mean nasal pH was significantly lower in the CF group. Nasal potential difference may have been a confounding factor; study 2) in a fresh cohort of CF and non-CF subjects, no significant difference was found between the two groups using a gold pH probe; study 3) simultaneous nasal pH measurements were made in 15 CF and 15 non-CF adults using both probes. In the CF group, there was a trend for the antimony probe to read lower than the gold probe. In the non-CF group, the antimony probe read higher. The pH difference noted in study 1 related to technical factors; study 4) the effect of acute changes in serum acid/base balance on nasal pH was assessed in five non-CF adults. Nasal pH was not altered by either acute respiratory acidosis or alkalosis; study 5) nasal and lower airway pH was measured in five CF and six non-CF children. No difference was found between the groups. There was a correlation between nasal and lower airway pH.The authors conclude that airway surface pH does not differ between cystic fibrosis and noncystic fibrosis subjects and therefore, cystic fibrosis transmembrane conductance regulator may not play a major role in airway surface pHin vivo.