bluuebunny/crossref_metadata_2025 huggingface dataset:
Methodology and Design of Field Experiments for Monitoring the Hygrothermal Performance of Wood Frame Enclosures
Authors: Straube John , Onysko Don , Schumacher Chris
Published: May 2003

Measurement of heat, air and moisture (HAM) phenomena in building assemblies under both controlled conditions and field conditions are difficult to achieve with uniform accuracy and reliability. Care is needed in selecting the measurement sensors and instrumentation to achieve an acceptable degree of accuracy. When the experiments are planned to answer specific questions or to confirm expected responses, the degree of accuracy needed is pre-determined. Proper calibration coupled with appropriate selection of materials can improve the reliability of the measurements, enhance the accuracy achieved, and ensure that the installation has the durability to survive for as long as is needed by the experiment.

The field and laboratory experience of the authors in undertaking HAM measurements, particularly those involving transient conditions arising from exposure to real weather, are the basis for the recommendations provided here. The limitations in both undertaking certain measurements and in the interpretation of some data are addressed. The complex of interactions related to the driving forces and changes in material properties prevents experimenters from attributing certain outcomes to particular theoretical assumptions. However, field studies are complementary to carefully executed laboratory studies. As the accuracy of theory increases, there will be an increased need for detailed and accurate field measurements.
Experimental Investigation of the Effect of Natural Convection on Heat Transfer in Mineral Wool
Authors: Dyrbøl Susanne , Svendsen Svend , Elmroth Arne
Published: May 2003

In Denmark and a number of other countries convection in fibrous materials is considered non-existent when calculating heat transmission as well as when designing building structures. The current investigation serves to examine whether considering natural convection non-existent in fibrous materials is a fair assumption to use in present and future building structures.

In order to facilitate the experimental work, an apparatus with a metering area of 3 × 1 m2 was designed for measuring the effect of convection. With this apparatus it is possible to measure a specimen with thickness ranging from 0.1 to 0.5 m.

The contribution of natural convection to the total heat transfer has been experimentally examined for ‘‘perfectly’’ installed fibrous materials of different air-flow permeability and thermal conductivity. To support the interpretation of the measurements, the experimental work has been supplemented with numerical calculations.

The measurements and the concurrent computations both show a clear convection-induced redistribution of the heat flow in the material. When measured from the hot side in the apparatus this occurs in the form of an increased heat flow, primarily through the lower part of the vertical structure, and a decreased heat flow primarily through the upper part. The risk of convection causing the total heat flow in the material to increase is primarily related to the highly permeable material (corresponding with low density). In the low permeable material the redistribution of the heat flow has no influence on the total heat flow through the material. However, the redistribution of the convection-induced heat flow is distinct at a material thickness of 0.2 m and a temperature gradient of 20 C across the material.

This research has established that when the permeability reaches a certain level, convection is able to increase the total heat flow by more than three percent, which is considered here as a significant level raised above the uncertainty in the measurement, even under the most ideal conditions even at small temperature differences. This means that the commonly accepted assumption that convection is non-existent is invalid.
Effect of Surface Temperature on Water Absorption Coefficient of Building Materials
Authors: Mukhopadhyaya Phalguni , Kumaran Kumar , Normandin Nicole , Goudreau Patrick
Published: May 2003

Water absorption coefficient of a material governs the liquid moisture movement into it. In the case of various components of a building envelope, in particular exterior claddings, this is one of the most important hygrothermal material properties that needs to be assessed to determine the overall moisture management strategy. In different geographical locations, components of the building envelope, in particular the surface of the exterior cladding, are exposed to various temperature regimes. However, the effect of various temperature regimes on the water absorption coefficient of common building materials has not been adequately investigated. This study looks at the water absorption characteristic, determined through water absorption test, of three commonly used building materials (i.e., eastern white pine, red clay brick and concrete)at four temperature levels at the surface of the material, ranging from 3 to 35° C. A clear surface temperature effect on water absorption coefficient and derived liquid diffusivity value is shown in eastern white pine whereas changing the surface temperature shows no effect on the water absorption characteristic of red clay brick and concrete.
Water and Water Vapor Penetration Through Coatings
Authors: Ĉerny Robert , Podêbradská Jitka , Drchalová Jaroslava
Published: May 2003

Water and water vapor transport in two-layer systems where one layer acts as water retarder are analyzed. In the experimental work, four external paints supposed to protect the underlying structure against water under common service conditions are applied on glass fiber reinforced concrete substrates. The water absorption coefficient and the effective water vapor diffusion coefficient are chosen as evaluation parameters for the assessment of water and water vapor transport properties of the systems. In the water absorption experiments, two consecutive quasi-steady regimes are identified, the first with an almost constant water flux into the system, and the second obeying the square-root-of-time rule for cumulative mass of water in the system. The water protective qualities of all studied paints can be considered as satisfactory for common service conditions. The effective diffusion coefficients of all systems are found to be within the error range of the measuring method compared to the substrate itself, which is a very positive feature for external paints.
Administrative Practice and Rational Inquiry in Postmodern Public Administration Theory
Authors: de Zwart Frank
Published: May 2003

This article explores postmodern reasoning in academic public administration. It argues that the antiscience and proliberation arguments that abound in postmodern writing in public administration are informed by a fallacy: conflating administrative practice and the scientific study of that practice. In effect, postmodernists confuse wrongs of bureaucracy with arguments against modern science and then propagate relativism to clear up the muddle they created. This article opposes that package deal. It argues that the main objection postmodern authors have against science and administration—neglect of the variety of subjects’ points of view—has nothing to do with positivism or modern science and cannot be cured with relativism.
Women, Progressive-Era Reform, and Scientific Management
Authors: Schachter Hindy Lauer
Published: May 2003

Questions have been raised about the relation of Progressive-Era women reformers to scientific management and the efficiency concept associated with it. This article brings evidence from organizations such as the National Consumers League and the Taylor Society to argue that in the Progressive Era female reformers belonged to a community of discourse close to scientific management. Understanding this relationship helps delineate the intellectual foundations of progressive reform.
Air Pressure and Building Envelopes
Authors: Lstiburek Joseph , Pressnail Kim , Timusk John
Published: May 2003

Control of airflow is essential to several important performance aspects of the building system. Air carries moisture which impacts a material’s longterm performance (serviceability) and structural integrity (durability), behavior in fire (smoke spread), indoor air quality (distribution of pollutants and microbial reservoirs) and thermal energy.

Typical case studies are presented to illustrate how each of the above characteristics is affected when unintended airflow occurs as a result of poor construction. In some cases, there was simply a lack of understanding of the consequences of ignoring potential leakage paths and the interaction of the mechanical conditioning systems with the building structure. Rehabilitation of a troubled building requires that these interactions be understood. In general, the approach to developing that understanding is not involved.
Phenolic Binder Content Impact on Total Heat Transfer for Fibrous Insulation Batts
Authors: Harris K.T. , Roux J.A. , Mccarty T.A.
Published: May 2003

The total heat transfer through fibrous insulations for residential applications is comprised of coupled conduction, volumetric radiation, heat transport associated with H2O vapor mass transfer and heat transport due to the adsorption and desorption of bound H2O within the binder material of the fiberglass batt. Having previously studied the insulation thickness impact and the insulation substrate impact both analytically/numerically and experimentally, it was the purpose here to analytically/numerically study the impact of varying the phenolic binder content to determine its effect on the overall heat transfer for the coupled modes of heat transfer mentioned above. The phenolic binder coating on the glass fiber is hygroscopic and acts as a desiccant within the fiberglass insulation with regards to the adsorption and desorption of H2O. This in turn can impact the vapor H2O gradients and temperature gradients within the batt and hence impact the overall heat transfer. The purpose of this work is to predict the impact of varying the phenolic binder content on the overall heat transfer through an insulation batt which could be used for residential applications.
Heat Transfer Characteristics and Optimum Insulation Thickness for Cavity Walls
Authors: Al-Sanea Sami A. , Zedan M.F. , Al-Ajlan Saleh A. , Abdul Hadi Atif S.
Published: May 2003

The optimum thickness of insulation layers in cavity walls in buildings is determined under steady periodic conditions using the climatic data of Riyadh, Saudi Arabia. Different insulation materials are investigated at different locations in the cavity for a west-facing wall. The yearly cooling and heating transmission loads are calculated by an implicit finite-volume procedure that has been previously validated. These loads are used in an economic model based on the present worth analysis in order to minimize the total cost. Air spaces and insulation layers with different surface conditions and thickness are investigated and compared with the limiting cases with no air space or with no insulation. The results show that the most economical cavity configuration depends on the insulation material used. Under the conditions of the present study, polyurethane board and rock wool are found to be more cost effective when used alongside air spaces, while polystyrene is most cost effective when used with no air space. Among all configurations and insulation materials considered, a 9-cm-thick molded polystyrene layer with no air space is found to be the most economical. Thermal characteristics in the form of yearly transmission loads, and yearly averaged-dynamic R-value, time lag and decrement factor are presented versus insulation thickness.
Hygric Material Properties of Porous Building Materials
Authors: Häupl Peter , Fechner Heiko
Published: May 2003

The erection of new buildings, the renovation and preservation of building structures and monuments requires the quantification of the temperature, moisture, salt and pollution distribution in porous materials. The thermophysical modeling leads to a coupled nonlinear differential equation system. The temperature T and the capillary pressure pc will be used as driving potentials in this transport system. The air and salt transport and the crystallization and ice forming have been neglected in this paper although this processes have been formulated, too.

In order to solve the transport equation system with modern numerical methods the material functions thermal conductivity λ(w( pc),T ), capillary conductivity K(w( p c),T ) and vapor conductivity δ(w( pc), T ) and the moisture retention function w( pc,T ) are necessary. This paper will be focused on the determination of w( pc) and K(w( pc)) in the isothermic case. The results will be compared with measurement results of the capillary active insulation material ``calciumsilicate''.
Moisture Transport Across Interfaces Between Autoclaved Aerated Concrete and Mortar
Authors: Xiaochuan Qiu  , Haghighat Fariborz , Kumaran Mavinkal K.
Published: May 2003

Experiments were carried out to study the moisture transport across bonded or natural contact interface between autoclaved aerated concrete (AAC) and mortar. Bonded contact, in the present study, refers to the contact between two building materials involving penetration of pore structure with a bonding agent, while natural contact refers to the good physical contact between two building materials without penetration of pore structure. The moisture content profiles were measured using gamma ray spectrometer. The experimental results showed that, for both types of contact, the assumption of imperfect hydraulic contact is more appropriate than the widely used assumption, perfect hydraulic contact. Furthermore, the latter assumption may result in significant error in predicting moisture transport. The mismatching resistance was assumed in the study to explain the impact of imperfect hydraulic contact on the moisture transport. In addition, a numerical model was developed to calculate the moisture transport in multilayered materials and was applied to estimate either the mismatching resistance of the interface or the resistance of air films. For a specimen without an interface, the agreement between model prediction and experimental results was good. It was found that mismatching resistance of the interface varied with moisture content, the type of source material, and the interface with the sink material. This study indicates that the bonded interface can be approximately treated as the natural contact interface, while the presence of an air gap between AAC and AAC could significantly increase the resistance to moisture transport from one material to another.
Flux shielded arc butt welding of concrete reinforcing steel
Authors: Tušek J. , Golob V. , Arbi D.
Published: May 2003

The present paper reports on a new variant of flux shielded arc butt welding without the addition of a filler material, applied to steel bars for concrete reinforcement. The welding process is described, including the arc ignition and forcing together of the workpieces, via the application of a mechanical force, to form an upset. A new portable machine is described, using which it is possible to apply flux shielded arc welding on site. Experiments were carried out, from which optimum welding parameters such as welding current, weld time, and upsetting force were found. The strength properties of the welded joints obtained were determined via mechanical testing, i.e. a bend test, a tensile strength test, and an impact toughness test. Macroscopic sections of the welded joints were also produced. A quality analysis of the butt welded joints showed that the mechanical properties of the joints were equivalent or even superior to the properties of the parent metal.
Classification of severe asthma exacerbations: a proposal
Authors: Picado C
Published: May 2003

The intensity of asthma exacerbations may vary from mild to severe. Many studies have demonstrated that the speed at which severe asthma exacerbation (SAE) develops varies among patients. In some asthmatics, the exacerbation comes on very quickly, whereas in others there is a progressive deterioration of clinical, functional and blood gas parameters. Sudden SAE are characterised by their explosive presentation and quick recovery. This evolution contrasts with that of patients with a slow onset SAE, who often need prolonged hospitalization. Absence of secretions suctioned from the airways during mechanical ventilation has been reported in sudden SAE, whereas large amounts of viscid mucus are found in patients with the slow onset SAE. The lungs of patients who died during a sudden onset SAE often show empty airways and a predominant neutrophilic infiltration in the bronchial epithelium, in contrast to the presence of abundant eosinophils in patients who died during a slow onset SAE. Sudden onset SAE may occur as sporadic cases or in outbreaks. Sporadic cases may result from the ingestion of nonsteroidal anti-inflammatory drugs (NSAID) in patients with intolerance to these products, massive exposure to common allergens and ingestion of foods containing sulphites. Asthma outbreaks have been described in many cities. In contrast to sudden onset SAE, slow onset SAE is characterized by a progressive deterioration, accompanied by an increase in the use of bronchodilators. Lack of appropriate monitoring of function by peak expiratory flow (PEF) recording, failure of patients to recognize worsening symptoms and underusage of inhaled and oral steroid treatment have been repeatedly identified as factors which are likely to be associated with slow onset SAE. The contribution of psychosocial problems, depression, denial of asthma severity and nonadherence with the treatment should not be overlooked in patients with slow onset SAE. Classification of severe asthma exacerbations into two types (sudden onset and slow onset) could help to reveal the aetiology of the attack and may also be relevant to the management of the patient.
Effect of surgical lung volume reduction on respiratory muscle function in pulmonary emphysema
Authors: Teschler H , Stamatis G , el-Raouf Farhat AA , Meyer FJ , Costabel U , Konietzko N
Published: May 2003

Lung volume reduction surgery (LVRS) in patients with severe lung emphysema restores the thoracic configuration to a more normal functional capacity. The aim of this study was to investigate whether reduction in intrathoracic volume by LVRS improves the inspiratory muscle force generation of the respiratory pump. Pulmonary function tests, maximal inspiratory mouth pressure (MIP), sniff nasal inspiratory pressure (SNIP), sniff transdiaphragmatic pressure (Pdi), and inspiratory mouth occlusion pressure (P0.1) were measured in 17 emphysematous patients (mean (+/- SEM) age 53 +/- 2 yrs) before and 1 month after LVRS. The mean value of forced expiratory volume in one second (FEV1) increased (0.82 +/- 0.07 vs 1.12 +/- 0.08 L; p < 0.0001), whilst there was a decrease (p < 0.0001) in residual volume (RV) (337 +/- 31 vs 250 +/- 21 % of predicted), functional residual capacity (FRC) (210 +/- 9 vs 159 +/- 9% pred), and total lung capacity (TLC) (138 +/- 6 vs 110 +/- 5% pred). The mean value of MIP increased by 52% from 4.8 +/- 0.4 to 7.3 +/- 0.6 kPa (p < 0.001), the mean value of SNIP increased by 66% from 3.9 +/- 0.4 to 6.5 +/- 0.5 kPa (p < 0.001), and the mean value of Pdi increased by 28% from 6.0 +/- 0.6 to 7.7 +/- 0.8 kPa (p < 0.05) after LVRS. P0.1 decreased on average by 24% from 0.46 +/- 0.03 to 0.35 +/- 0.02 kPa after LVRS. No significant correlations were found between inspiratory muscle (MIP, SNIP, Pdi) and respiratory drive (P0.1) indices, lung function data, 6 min walk distance, or dyspnoea score. In conclusion, the observed clinical improvement of patients with severe emphysema after lung volume reduction surgery results, in part, from an increased ability of the inspiratory muscles to generate force, which is paralleled by a significant decrease in central respiratory drive.
Physiological and morphological determinants of maximal expiratory flow in chronic obstructive lung disease
Authors: Tiddens HA , Bogaard JM , de Jongste JC , Hop WC , Coxson HO , Pare PD
Published: May 2003

Maximal expiratory flow in chronic obstructive pulmonary disease (COPD) could be reduced by three different mechanisms; loss of lung elastic recoil, decreased airway conductance upstream of flow-limiting segments; and increased collapsibility of airways. We hypothesized that decreased upstream conductance would be related to inflammation and thickening of the airway walls, increased collapsibility would be related to decreased airway cartilage volume, and decreased collapsibility to inflammation and thickening of the airway walls. Lung tissue was obtained from 72 patients with different degrees of COPD, who were operated upon for a solitary peripheral lung lesion. Maximal flow-static recoil (MFSR) plots to estimate upstream resistance and airway collapsibility were derived in 59 patients from preoperatively measured maximal expiratory flow-volume and pressure-volume curves. In 341 transversely cut airway sections, airway size, airway wall dimensions and inflammatory changes were measured. Airflow obstruction correlated with lung elastic recoil and the MFSR estimate of airway conductance but not to airway collapsibility or to the amount of airway cartilage. The upstream conductance decreased as the inner wall became thicker. Airway collapsibility did not correlate with the amount of airway cartilage, inflammation, or airway wall thickness. We conclude that the maximal flow-static recoil model does not adequately reflect the collapsibility of the flow-limiting segment.
Evaluation of an auto-nCPAP device based on snoring detection
Authors: Lofaso F , Lorino AM , Duizabo D , Najafi Zadeh H , Theret D , Goldenberg F , Harf A
Published: May 2003

We evaluated an auto-nasal continuous positive airway pressure (nCPAP) prototype (MC+; SEFAM, Nancy, France) in which apnoea/hypopnoea detection was disabled and nasal mask pressure vibration detection was the only mode of pressure setting. The device was tested in 15 previously untreated obstructive sleep apnoea patients during a night with polysomnography. We observed that a single night of auto-nCPAP improved the apnoea/hypnoea index (AHI) (12 +/- 21 vs 51 +/- 31 disordered breathing events.h-1 of sleep (mean +/- SD)), the awakening-arousal index (13 +/- 20 vs 40 +/- 26 arousals.h-1 of sleep), and duration of slow wave sleep (102 +/- 49 vs 71 +/- 56 min) but not of rapid eye movement (REM) sleep (55 +/- 31 vs 64 +/- 38 min). Auto-nCPAP was effective (apnoea/hypopnoea and arousal indices < 10 events.h-1) in all but three patients. Auto-nCPAP was ineffective in one patient, whose obstructive respiratory events were not preceded by nasal mask pressure vibration detection, and in two patients who were quasi-permanent mouth breathers. Snoring detection may be effective in sleep apnoea syndrome with heavy snoring and without permanent mouth breathing, during the first night of nasal continuous positive airway pressure treatment.
Relationship between body mass index, age and upper airway measurements in snorers and sleep apnoea patients
Authors: Mayer P , Pepin JL , Bettega G , Veale D , Ferretti G , Deschaux C , Levy P
Published: May 2003

Anatomical pharyngeal and craniofacial abnormalities have been reported using upper airway imaging in snorers with or without obstructive sleep apnoea (OSA). However, the influences of the age and weight of the patient on these abnormalities remain to be established. The aim of this study was, therefore, to evaluate in a large population of snorers with or without OSA, the relationship between body mass index (BMI), age and upper airway morphology. One hundred and forty patients were referred for assessment of a possible sleep-related breathing disorder and had complete polysomnography, cephalometry and upper airway computed tomography. For the whole population, OSA patients had more upper airway abnormalities than snorers. When subdivided for BMI and age, however, only lean or younger OSA patients were significantly different from snorers as regards their upper airway anatomy. The shape of the oropharynx and hypopharynx changed significantly with BMI both in OSA patients and snorers, being more spherical in the highest BMI group due mainly to a decrease in the transverse axis. On the other hand, older patients (> 63 yrs), whether snorers or apnoeics, had larger upper airways at all pharyngeal levels than the youngest group of patients (< 52 yrs). For the total group of patients, upper airway variables explained 26% of the variance in apnoea/hypopnoea index (AHI), whereas in lean (BMI < 27 kg.m-2) or youngest (age < 52 yrs) subjects upper airway variables explained, respectively 69 and 55% of the variance in AHI. In conclusion, in lean or young subjects, upper airway abnormalities explain a major part of the variance in apnoea/hypopnoea index and are likely to play an important physiopathogenic role. This study also suggests that the shape of the pharyngeal lumen in awake subjects is more dependent on body mass index than on the presence of obstructive sleep apnoea. Further investigation looking at upper airway imaging for surgical selection in obstructive sleep apnoea should focus on lean and young patients.
Respiratory challenge induces high frequency spiking on the static charge sensitive bed (SCSB)
Authors: Kirjavainen T , Polo O , McNamara S , Vaahtoranta K , Sullivan CE
Published: May 2003

The static charge sensitive bed (SCSB) is a simple and noninvasive device used for the detection of sleep apnoea. In addition to episodes of apnoea or hypopnoea, heavy snorers commonly present with episodes of high frequency spiking on the SCSB. These spiking episodes have been claimed to represent partial upper airway obstruction during sleep, but the mechanism of their appearance is not known. We studied the SCSB spiking phenomenon in awake subjects during experimental respiratory challenge. One female and five male volunteers were studied whilst breathing freely, during hypoxia, hypercapnia and inspiratory and expiratory loading. Oxygen saturation, end-tidal carbon dioxide tension, minute ventilation, oesophageal pressure, electrocardiographic activity (ECG), blood pressure and the SCSB signals were monitored. During free breathing, the SCSB high frequency signal consisted of low amplitude complexes with close time relationship to the cardiac cycle. During respiratory challenge, spiking occurred. These spikes showed no time relationship to the cardiac cycle, but were time-linked to the onset of inspiration or expiration. Spike amplitude correlated with breathing frequency (r2 = 0.59; p < 0.005) and variation in oesophageal pressure (r2 = 0.57; p < 0.005). We conclude that during quiet, unobstructed breathing the static charge sensitive bed high frequency signal represents cardiac activity (ballistocardiogram), whereas during high-drive breathing high frequency spikes are produced. These spikes are respiratory in origin and are likely to represent fast components of respiratory movements. Our results support the use of static charge sensitive bed spiking as a noninvasive measure of breathing stimulation.
Benzodiazepine receptor antagonist (flumazenil) does not affect sleep-related breathing disorders
Authors: Schonhofer B , Kohler D
Published: May 2003

Benzodiazepine drugs may impair breathing during sleep, leading to the development of sleep-disordered breathing or, in subjects with sleep apnoea, an increase in the severity of pre-existing apnoeas. Flumazenil is a selective benzodiazepine-antagonist. We hypothesized that endogenous ligands of benzodiazepine receptors might contribute to the pathogenesis of obstructive sleep apnoea syndrome (OSAS) and that the intensity of OSAS could, therefore, be reduced by flumazenil. Ten male patients (mean age 55 yrs, mean body mass index 42.4 kg.m-2, mean apnoea index (AI) 53.5 and mean respiratory disturbance index (RDI) 74.2) were investigated. None of the patients had been treated for OSAS prior to the study. The study design was randomized, single-blind, placebo-controlled and cross-over. On the first or second study night, patients were randomly assigned to receive i.v. flumazenil (2 mg) or placebo (0.9% NaCl) between 01:00 and 01:30 h. Comparing the polysomnographic results of the placebo night and the flumazenil night in all 10 patients, no significant differences were found regarding obstructive events or sleep architecture. Accordingly, the data concerning sleep-disordered breathing and sleep stages during the 30 min period prior to and the 30 min period following the administration of flumazenil did not differ. It is concluded that endogenous ligands of the benzodiazepine receptor play no role in the pathogenesis of obstructive sleep apnoea syndrome, since respiratory and sleep data are not altered by flumazenil. Therefore, attempts to treat obstructive sleep apnoea syndrome with flumazenil do not seem to be warranted.
Cost-effectiveness of video-assisted thoracoscopic surgery versus conservative treatment for first time or recurrent spontaneous pneumothorax
Authors: Schramel FM , Sutedja TG , Braber JC , van Mourik JC , Postmus PE
Published: May 2003

The aim of this study was to analyse differences in efficacy and costs in treating first time or recurrent spontaneous pneumothorax by conservative therapy (pleural drainage or observation) and video-assisted thoracoscopic surgery (VATS). Retrospectively, 112 patients treated by conservative therapy during 1985-1989 (Period 1) were compared with 97 patients treated by VATS during 1991-1994 (Period 2). Mean follow-up time in each period was more than 2 yrs. Patients in both periods had comparable clinical characteristics. Irrespective of first time or recurrent spontaneous pneumothorax at presentation, drainage and hospitalization times were longer, and complication and recurrence rates were higher in Period 1. When costs due to the waiting time before VATS were excluded, the total costs in Period 1 were higher than in Period 2. Video-assisted thoracoscopic surgery is more effective in treating patients with first time or recurrent spontaneous pneumothorax, with less morbidity and total costs compared to conservative therapy. In view of cost-effectiveness, we feel that a different management of first time or recurrent spontaneous pneumothorax is not justified.
Prognostic significance of thrombocytosis in patients with primary lung cancer
Authors: Pedersen LM , Milman N
Published: May 2003

In patients with malignancies, thrombocytosis has previously been related to disease stage, histological type, and survival. In the present study, the prevalence of thrombocytosis and the prognostic information provided by platelet counts were analysed in a large cohort of patients with primary lung cancer. At the time of diagnosis, pretreatment platelet counts were retrospectively recorded in 1,115 consecutive patients with histologically proven primary lung cancer. All patients were reviewed regarding histological type, tumour, node, metastasis (TNM) classification stage and survival. The prevalence of thrombocytosis in patients with lung cancer was compared with that in a series of 550 consecutive out-patients with benign lung disorders. In 269 surgically resected patients, postoperative platelet counts were recorded 1-3 months after resection of the tumour. In the follow-up period, thromboembolic episodes diagnosed either clinically or at autopsy were recorded. The overall prevalence of thrombocytosis (> 400 x 10(9) platelets.L-1) in the patients with lung cancer was 32%. The frequency of thrombocytosis was significantly higher compared with the control subjects (32 vs 6%; p < 0.0001). Platelet counts differed significantly among subgroups defined by the TNM classification, with the proportion of patients with > 400 x 10(9) platelets.L-1 greatest in the more advanced TNM stages (stage I and II 23% vs stage III and IV 37%; p < 0.0001). Patients with thrombocytosis had a significantly poorer survival than patients with normal platelet counts (p < 0.0001). In a multivariate survival analysis (Cox model), thrombocytosis continued to correlate strongly with poor survival even when adjusted for histological type, sex, age, and TNM stage (p < 0.001). In surgically resected patients, the frequency of preoperative and postoperative thrombocytosis differed significantly (23.0 vs 8.9%; p < 0.0001). Survival rate was significantly reduced in patients with preoperative thrombocytosis (p = 0.005). Thrombocytosis was not associated with an increased incidence of thromboembolism. In conclusion, thrombocytosis is an independent prognostic factor of survival in patients with primary lung cancer. We suggest that platelet counts should be included in future multivariate analyses of survival in patients with lung cancer.
ICAM-1 expression by lung cancer cell lines: effects of upregulation by cytokines on the interaction with LAK cells
Authors: Melis M , Spatafora M , Melodia A , Pace E , Gjomarkaj M , Merendino AM , Bonsignore G
Published: May 2003

Intercellular adhesion molecule-1 (ICAM-1) expression by tumour cells may be involved in their interaction with defensive cells. In this study the surface ICAM-1 expression and soluble ICAM-1 (sICAM-1) production by five small cell lung cancer (SCLC) and five non-SCLC (NSCLC) cell lines was investigated. In addition, the effects of ICAM-1 upregulation by cytokines on the adhesion of lung cancer cells to allogeneic lymphokine-activated killer (LAK) cells and susceptibility to LAK cytotoxicity was also evaluated. ICAM-1 expression was assessed by flow cytometry. Soluble ICAM-1 release was measured by enzyme-linked immunosorbent assay (ELISA). Interaction with LAK cells was tested by adhesion and cytotoxicity assays. At baseline, SCLC lines did not express ICAM-1, while 4 of the 5 NSCLC lines expressed ICAM-1. ICAM-1 expression was induced by interferon-gamma (IFN-gamma) in 4 of the 5 SCLC lines and upregulated in 1 of the 5 NSCLC lines. ICAM-1 expression was induced by tumour necrosis factor-alpha (TNF-alpha) in 1 of the 5 SCLC lines (National Cancer Institute (NCI) H211), and upregulated in 2 of the 5 NSCLC lines (NCI H460 and NCI H838). Among the latter lines, one (NCI H838) released significant amounts of sICAM-1. Adhesion to LAK cells and susceptibility to LAK cytotoxicity were significantly higher in TNF-alpha-treated NCI H460 and NCI H211 cells, compared to untreated NCI H460 and NCI H211 cells. In contrast, no difference in adhesion to LAK cells and susceptibility to LAK cytotoxicity was detected between baseline and TNF-alpha-treated NCI H838 cells. Intercellular adhesion molecule-1 surface expression and soluble intercellular adhesion molecule-1 release may play an important role in interactions between lymphokine-activated killer cells and lung cancer cells.
Cell cultures from bronchial subepithelial myofibroblasts enhance eosinophil survival in vitro
Authors: Zhang S , Mohammed Q , Burbidge A , Morland CM , Roche WR
Published: May 2003

Mechanisms of eosinophil accumulation and activation in the bronchial mucosa are crucial for the pathogenesis of asthma. The location of specialized fibroblasts, myofibroblasts, beneath the bronchial basement membrane and their proximity to infiltrating eosinophils potentially enable the myofibroblasts to modulate eosinophil survival and function in asthma. The aim of this study was to investigate the effects of bronchial myofibroblasts on eosinophil survival in vitro. Eosinophils from human peripheral blood were exposed to cell cultures from bronchial myofibroblasts and to myofibroblast-conditioned media. Eosinophil viability was assessed and granulocyte/macrophage colony-stimulating factor (GM-CSF) production was examined in co-culture supernatants and as messenger ribonucleic acid (mRNA) in myofibroblasts. Eosinophil survival was significantly increased and eosinophil apoptosis was inhibited by co-culture with myofibroblasts. Conditioned medium from tumour necrosis factor-alpha (TNF-alpha)-stimulated myofibroblasts also prolonged eosinophil survival. This effect could be blocked by GM-CSF antibody. GM-CSF mRNA and secretion from myofibroblasts were increased in co-cultures and by eosinophil-conditioned medium. Addition of antibodies to TNF-alpha and interleukin-1 alpha (IL-1 alpha) to co-cultures resulted in significant reduction both in eosinophil survival and GM-CSF levels. Blocking of fibronectin in the co-cultures did not affect the eosinophil survival enhancing activity. Prednisolone inhibited the eosinophil survival enhancing activity of the co-cultures by suppression of GM-CSF production. Soluble eosinophil-derived cytokines are involved in the interaction of eosinophils with myofibroblasts, which results in a tumour necrosis factor-alpha/interleukin-1 alpha mediated release of granulocyte/macrophage colony-stimulating factor from myofibroblasts. Bronchial myofibroblasts can, thereby, contribute to allergic inflammation by granulocyte/macrophage colony-stimulating factor-mediated inhibition of eosinophil apoptosis.
In vivo exposure to nitrogen dioxide (NO2) induces a decrease in calcitonin gene-related peptide (CGRP) and tachykinin immunoreactivity in guinea-pig peripheral airways
Authors: Lucchini RE , Springall DR , Chitano P , Fabbri LM , Polak JM , Mapp CE
Published: May 2003

The mammalian respiratory tract is densely innervated by sensory and autonomic fibres. Subsets of the nerves contain bioactive regulatory peptides, such as substance P, calcitonin gene-related peptide (CGRP), and neurokinins. The sensory nervous system responds to inhaled irritants, resulting in a release of neuropeptides and, thus, a decrease in the peptide immunoreactivity of the fibres. We examined the effects of inhaled nitrogen dioxide (NO2), a well-known indoor and outdoor air pollutant, on pulmonary sensory neuropeptides. Guinea-pigs were exposed for 4 h to 18 parts per million (ppm) NO2 or to air (n = 5 each). At the end of the exposure, they were killed with urethane and their lungs were fixed in 1% paraformaldehyde in phosphate-buffered saline. Cryostat sections were stained with antisera to an anatomical nerve marker, protein gene product (PGP) 9.5, and to CGRP and tachykinins, utilizing the avidin-biotinylated peroxidase method. In the noncartilaginous airways (diameter < 250 microns) of NO2-exposed animals, less tachykinin- and CGRP-immunoreactive nerve fibres were found compared with controls. No change was seen in the total nerve fibre distribution (PGP 9.5). It is concluded that the peptidergic nerves of guinea-pig peripheral airways are a sensitive indicator of exposure to nitrogen dioxide.
Effect of short-term NO2 exposure on induced sputum in normal, asthmatic and COPD subjects
Authors: Vagaggini B , Paggiaro PL , Giannini D , Franco AD , Cianchetti S , Carnevali S , Taccola M , Bacci E , Bancalari L , Dente FL , Giuntini C
Published: May 2003

The aim of this study was to assess the effects of short-term exposure to low levels of nitrogen dioxide (NO2) on airway inflammation. We studied seven normal, eight mild asthmatic and seven chronic obstructive pulmonary disease (COPD) subjects. All subjects were exposed to air or to 0.3 parts per million (ppm) NO2 for 1 h, with moderate intermittent exercise, on different days and in random order. Before and 2 h after exposure, symptom score and results of pulmonary function tests (PFTs) were assessed. All subjects performed nasal lavage and hypertonic saline (HS) inhalation to collect sputum 2 h after both exposures. Asthmatic subjects had a higher percentage of eosinophils than normal and COPD subjects in HS-induced sputum after air (asthmatics: median 13 (range 0.4-37)%; normals: 0 (range 0-2)%; COPD 1.8 (range 0.1-19)%), whilst COPD patients showed a higher percentage of neutrophils than the two others groups. No significant differences in PFT values or percentages of inflammatory cells were observed in nasal lavage and in HS-induced sputum in normal, asthmatic and COPD subjects after NO2 exposure compared to air exposure, except for a mild decrease in forced expiratory volume in one second (FEV1) 2 h after NO2 exposure in COPD patients. Symptom score showed a mild increase after NO2 exposure both in normal subjects and in COPD patients. We conclude that short-term exposure to 0.3 ppm nitrogen dioxide does not induce an early detectable acute inflammation in proximal airways of normal subjects or of patients with asthma or chronic obstructive pulmonary disease.
Bronchoalveolar and systemic cytokine profiles in patients with ARDS, severe pneumonia and cardiogenic pulmonary oedema
Authors: Schutte H , Lohmeyer J , Rosseau S , Ziegler S , Siebert C , Kielisch H , Pralle H , Grimminger F , Morr H , Seeger W
Published: May 2003

The aim of this study was to investigate whether bronchoalveolar lavage (BAL) and serum levels of proinflammatory cytokines discriminate between different entities of patients with acute respiratory failure. BAL and circulating concentrations of interleukin-6 (IL-6), interleukin-8 (IL-8) and tumour necrosis factor-alpha (TNF-alpha) were measured in 74 mechanically-ventilated patients and 17 healthy controls. Patients were classified as cardiogenic pulmonary oedema (CPO), acute respiratory distress syndrome (ARDS), primary severe pneumonia (PN) and a combined group (PN+ARDS). In all patients with ARDS and/or PN, markedly elevated BAL levels of IL-6 and IL-8 were detected, which were significantly greater than levels in CPO and healthy controls. Absolute quantities and time-course of these cytokines did not differentiate between the absence and presence of lung infection, or different categories of PN. Similarly, circulating IL-6 levels were comparably elevated in patients with ARDS and/or PN, whereas circulating IL-8 concentrations were inconsistently increased. TNF-alpha was rarely detected in BAL samples, but increased serum concentrations were measured in ARDS and/or PN patients. Bronchoalveolar lavage levels of interleukin-6 and interleukin-8, but not tumour necrosis factor-alpha, and serum concentrations of interleukin-6 are consistently elevated in acute respiratory distress syndrome and/or severe pneumonia, discriminating these entities from cardiogenic pulmonary oedema. Alveolar and systemic cytokine profiles do not differentiate between acute respiratory distress syndrome in the absence of lung infection and states of severe primary or secondary pneumonia, which evidently present with comparable local and systemic inflammatory sequelae.
Gastric intramucosal pH: an indicator of weaning outcome from mechanical ventilation in COPD patients
Authors: Bouachour G , Guiraud MP , Gouello JP , Roy PM , Alquier P
Published: May 2003

The aim of this study was to determine whether gastric intramucosal pH (pHim) and/or gastric intramucosal carbon dioxide tension (PCO2,im) measured by tonometry can be used to predict the success of weaning in chronic obstructive pulmonary disease (COPD) patients. Twenty six consecutive COPD patients, undergoing mechanical ventilation for acute respiratory failure and satisfying the criteria of weaning from mechanical ventilation with nasogastric tonometer in place, were studied. Arterial blood gas values and PCO2,im were measured 24 h before (H-24), just before (H0), and after 20 min of a weaning trial on T-piece (H20min). Weaning failure was defined as the development of respiratory distress and/or arterial blood gas impairments during the first 2 h of spontaneous breathing on T-piece, or reintubation within 24 h after extubation. Between the weaning failure (n = 6) and weaning success (n = 20) groups, there were no differences in blood gas analysis readings at H-24 and H0 before the weaning period, age, Simplified Acute Physiology Score (SAPS) on admission, SAPS on the day of weaning trial, and duration of ventilation. Clinical status, tonometric and arterial gasometric data were similar at H-24 and H0 in all patients. During mechanical ventilation, pHim was < or = 7.30 in patients who failed weaning and > 7.30 in patients who were successfully weaned (p < 0.001; 100% sensitivity and specificity). The threshold value for PCO2,im of 8.0 kPa (60 mmHg) represents a clear demarcation with respect to outcome before the weaning trial. PCO2,im values during mechanical ventilation are significantly different (p < 0.001) between patients who were successfully weaned and those who were not (6.9 +/- 0.9 vs 9.9 +/- 1.1 kPa (51.9 +/- 6.7 vs 74.3 +/- 8.0 mmHg, respectively)). At H20min, pHim and PCO2,im were still statistically different between the weaning failure and the weaning success group. We conclude that measurement of gastric intramucosal pH (or gastric intramucosal carbon dioxide tension) represents a simple and accurate index to predict weaning outcome in chronic obstructive pulmonary disease patients before attempting weaning.
Mineralogical analysis of the respiratory tract in aluminium oxide-exposed workers
Authors: Voisin C , Fisekci F , Buclez B , Didier A , Couste B , Bastien F , Brochard P , Pairon JC
Published: May 2003

A retrospective study was conducted in order to characterize the retention of fibrous and nonfibrous mineral particles in the respiratory tract in subjects with previous occupational exposure in the aluminium industry. Bronchoalveolar lavage (BAL) fluid (three samples) or lung parenchyma (two samples) were studied using analytical transmission electron microscopy in five patients. A high concentration of aluminium fibres (> 10(7) fibres.g-1 dry lung) was identified in two lung tissue samples, and aluminium fibres were also identified in BAL fluid in three patients. All fibres were short (mean length: 1-2 microns), with no fibre longer than 5 microns. Some biopersistence of these fibres in the respiratory tract is suggested from these observations, since fibres were identified in biological samples collected more than 4 yrs after cessation of exposure in four out of five patients. Occupational physicians should be aware of possible exposure to short, thin aluminium fibres during primary aluminium production. Further studies are needed to assess the potential health effects of these fibres. Industrial hygiene measurements should also be performed to document the potential sources of exposure to aluminium fibres in this industry.
Total serum IgE is associated with asthma independently of specific IgE levels. The Spanish Group of the European Study of Asthma
Authors: Sunyer J , Anto JM , Castellsague J , Soriano JB , Roca J
Published: May 2003

In this study we aimed to assess whether the association between asthma (defined by symptoms and bronchial responsiveness) and total immunoglobulin E (IgE) levels was independent of specific IgE levels to common aeroallergens. A general population-based sample, supplemented with symptomatic individuals, comprising 1,916 young adults, aged 20-44 years, from five areas of Spain, performed a face-to-face respiratory questionnaire, and spirometry, and had total and specific serum IgE levels to mites, pets and moulds recorded. In 1,626 of the subjects, a dose-response methacholine challenge test was completed. Subjects reporting current attacks of asthma showed an association with total IgE (odds ratio (OR) for IgE > 100 kU.L-1 = 4.73, 95% confidence intervals (95% CI) = 2.01-11.12, adjusted for specific IgE, sex, age, smoking, forced expiratory volume in one second (FEV1), and area), which did not vary by bronchial responsiveness. The association between total IgE and asthma also occurred among those with negative specific IgE antibodies (OR 18.0; 95% CI 13.9-120). Individuals with current wheezing and bronchial responsiveness without attacks of asthma also showed an adjusted association with total IgE (OR 4.96; 95% CI 2.32-10.6), which remained for persons without specific IgE (OR 5.86; 95% CI 2.18-1.7). These findings reinforce previous evidence that asthma is associated with increased levels of total IgE, even in subjects negative for specific IgE to common aeroallergens.