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Biomedical subjects

Kenneth W T Tsang

Publications and source records attributed to Kenneth W T Tsang.

At least 19 recordsLinked to original sources
PubMed2006

Inhibition of pyocyanin-potentiated IL-8 release by steroids in bronchial epithelial cells.

Airway epithelial cells are the first targets of environmental stimuli and local cytokines. Pyocyanin-induced synergism with interleukin (IL)-1 or tumour necrosis factor (TNF) in triggering IL-8 release has been documented previously. In this study, IL-8 mRNA and protein expression were examined in cultured human bronchial epithelial cells (BEAS-2B) stimulated with pyocyanin alone, and in combination with IL-1beta or phorbol 12,13-dibutyrate (PDBu) in the absence and presence of a group of glucocorticoids. IL-8 mRNA was measured by RT-PCR, and IL-8 protein by ELISA (cell supernatants). Pyocyanin alone produced no increase in IL-8 mRNA and release. However, pyocyanin upregulated the stimulatory effect of IL-1beta or PDBu on the release of IL-8 in a dose-dependent manner. The stimulatory effect of pyocyanin on the IL-1beta- or PDBu-stimulated IL-8 release was reduced in the presence of dexamethasone, budesonide, and fluticasone. Budesonide and fluticasone were 10-fold more potent than dexamethasone. The protein kinase C (PKC) inhibitor, Go6976, also significantly reduced the stimulatory effect of pyocyanin on IL-1beta, and PDBu increased IL-8 release. In conclusion, this study shows that PKC signal pathway seems to be involved in the pyocyanin-mediated upregulation of the IL-1beta and PDBu-induced IL-8 release in BEAS-2B cells. These findings suggest that a vicious cycle perpetuating inflammation may exist in the biologic milieu of bronchiectatic patients infected with Pseudomonas aeruginosa due to the production of pyocyanin. The priming action of pyocyanin appears to be blocked by glucocorticoids, thus providing in vitro data in support of the clinical efficacy of inhaled glucocorticoids as anti-inflammatory drugs.

Androstadienes↗
PubMed2005

Elevated levels of transforming growth factor-beta(1) in serum of patients with stable bronchiectasis.

Bronchiectasis is a chronic inflammatory and infective airway disease characterized by irreversible dilatation of the bronchi and persistent purulent sputum. Transforming growth factor-beta(1) (TGF-beta(1)) has been found to be increased in the lungs or bronchoalveolar lavage fluid of patients with inflammatory lung diseases. However, little is known on the serum TGF-beta(1) levels in patients with bronchiectasis. We aimed to determine the serum TGF-beta(1) concentrations in 95 patients with stable bronchiectasis (63 women; mean+/-sd age, 58.9+/-14.1 years) and 68 control subjects (23 women; 48.9+/-12.8 years) by ELISA, and to correlate with clinical parameters. The serum TGF-beta(1) levels were significantly higher in bronchiectatic patients compared with control subjects (median [range], 1812.5 pg/ml [1226.4-4114.5 pg/ml] vs. 1342.4 pg/ml [940.3-2371.7 pg/ml]; P<0.001). There was, however, no correlation between serum TGF-beta(1) levels with FEV(1) (% predicted), FVC (% predicted), 24h sputum volume, the number of bronchiectatic lung lobes or total white blood cell count (P>0.05). Our findings support previous indications that TGF-beta(1) may contribute to bronchiectatic airway inflammation. Further studies on the potential mechanisms and pathogenesis implications of this elevation should also be pursued in future.

Adult↗
PubMed2005

Severe acute respiratory syndrome: pertinent clinical characteristics and therapy.

Severe acute respiratory syndrome (SARS) is a newly emerged infection that is caused by a previously unrecognized virus - a novel coronavirus designated as SARS-associated coronavirus (SARS-CoV). From November 2002 to July 2003 the cumulative number of worldwide cases was >8000, with a mortality rate of close to 10%. The mortality has been higher in older patients and those with co-morbidities. SARS has been defined using clinical and epidemiological criteria and cases are considered laboratory-confirmed if SARS coronavirus is isolated, if antibody to SARS coronavirus is detected, or a polymerase chain reaction test by appropriate criteria is positive. At the time of writing (24 May 2004), no specific therapy has been recommended. A variety of treatments have been attempted, but there are no controlled data. Most patients have been treated throughout the illness with broad-spectrum antimicrobials, supplemental oxygen, intravenous fluids, and other supportive measures. Transmission of SARS is facilitated by close contact with patients with symptomatic infection. The majority of cases have been reported among healthcare providers and family members of SARS patients. Since SARS-CoV is contagious, measures for prevention center on avoidance of exposure, and infection control strategies for suspected cases and contacts. This includes standard precautions (hand hygiene), contact precautions (gowns, goggles, gloves) and airborne precautions (negative pressure rooms and high efficiency masks). In light of reports of new cases identified during the winter of 2003-4 in China, it seems possible that SARS will be an important cause of pneumonia in the future, and the screening of outpatients at risk for SARS may become part of the pneumonia evaluation.

Algorithms↗
PubMed2004

Systemic oxidative and antioxidative status in Chinese patients with asthma.

BACKGROUND: Patients with asthma generate an increased amount of reactive oxygen species from peripheral blood cells. Reactive oxygen species produce many of the pathophysiologic changes associated with asthma and may contribute to its pathogenesis. OBJECTIVE: We investigated changes in antioxidant enzyme activities and oxidized glutathione (glutathione disulfide; GSSG) levels in erythrocytes from a group of healthy control Chinese subjects (n=135) and patients with asthma (n=106). METHODS: Baseline pulmonary function was measured for all subjects. Antioxidant status was evaluated by measuring erythrocyte superoxide dismutase, catalase, and glutathione peroxidase activities. Oxidative stress was also measured in terms of GSSG in erythrocytes with a kinetic microassay. RESULTS: Patients with asthma had significantly increased erythrocyte superoxide dismutase and catalase activities compared with controls (61.10 +/- 1.30 U/g hemoglobin [Hb] vs 55.51 +/- 1.82 U/g Hb [P=.018] and 0.0637 +/- 0.0021 U/g Hb vs 0.0257 +/- 0.0120 U/g Hb [P <.001] for the asthma and control groups, respectively). Conversely, erythrocyte glutathione peroxidase activity decreased (44.21 +/- 1.33 mU/g Hb vs 50.07 +/- 1.39 mU/g Hb for the asthma and control groups, respectively; P=.003). Patients with asthma also had significantly higher GSSG levels in erythrocyte hemolysates compared with controls (167.40 +/- 2.93 micromol/L vs 44.98 +/- 0.44 micromol/L for the asthma and control groups, respectively; P <.001), indicating increased oxidative stress. CONCLUSIONS: Asthma is accompanied by an alteration in systemic antioxidant status due to possible oxidative stress in this disease.

Adult↗
PubMed2004

Computed tomographic evaluation of the role of craniofacial and upper airway morphology in obstructive sleep apnea in Chinese.

OBJECTIVES: To evaluate the relationship between cephalometric parameters, upper airway morphological factors and obstructive sleep apnea (OSA) in Chinese subjects. DESIGN: Polysomnogram (PSG) were performed and scored using standard criteria. Supine lateral cephalometric parameters and pharyngeal cross-sectional areas at the level of velopharynx (VA) and hypopharynx (HA) were measured from computed tomographic scans. The roles of these parameters and other anthropometric/demographic characteristics in OSA (apnea hypopnea index, AHI > or = 5) and their relationship with severity of OSA were explored by multiple logistic and multinominal regression analysis. RESULTS: Ninety-two subjects, ranging from normal (n = 36), mild/moderate OSA (n = 34) to severe OSA (n = 22), were evaluated. Compared with normal subjects, OSA subjects were heavier (body mass index 27 vs. 24 kg/m2) and older (47 vs. 42 years of age); had smaller VA size and VA to HA ratio, lower positioned hyoid bone, longer and thicker soft palate, and more retropositioned mandible relative to maxilla. After controlling for body mass index and age, subjects with severe OSA (AHI > 30) had more retropositioned mandible relative to maxilla (odds ratio, OR 1.31, P = 0.044) and longer soft palate (OR 1.16, P = 0.01), while those with mild/moderate OSA had larger VA to HA ratio (OR 0.17, P = 0.018). CONCLUSIONS: Craniofacial factors and upper airway morphology contributed to severity of OSA in Chinese subjects. Having controlled for obesity, more retropositioned mandible was associated with more severe OSA.

Cephalometry↗
PubMed2004

In vitro study of regulation of IL-6 production in bronchiectasis.

Persistent airway inflammation is an important pathogenetic factor in bronchiectasis, and interleukin (IL)-6 is among the mediators implicated in regulation of inflammation in bronchiectatic airways. We postulated that airway secretion with its constituents of cytokines and enzymes would provide an environment for perpetuation of inflammation in vivo. We aimed to determine the action of sputum from patients with bronchiectasis on IL-6 production from cultured normal human bronchial epithelial (NHBE) cells and its modulation by anti-inflammatory drugs in vitro. Cultures of NHBE cells were tested with (i) sputum of bronchiectatic patients, (ii) anti-tumor necrosis factor-alpha (TNF-alpha) pre-treated sputum, or (iii) recombinant human (rh)-TNF-alpha. Alternatively, NHBE cells were incubated with one of the anti-inflammatory drugs before treatment with sputum or rh-TNF-alpha. IL-6 produced into the medium was assayed by ELISA. Sputum in bronchiectasis stimulated IL-6 production from NHBE cells by 1.9 times. This was largely attributable to TNF-alpha as pre-incubation of sputum sol with anti-TNF-alpha almost neutralized the sputum effect. Apart from dexamethasone, the other drugs exerted inhibitory effects on IL-6 production. Ibuprofen suppressed sputum-stimulated IL-6 production to levels above control and effect levelled off at 50-100 microg/mi, contrasting the dose-dependent suppression to control level with MK-663 (0.1-10 microg/ml) and to sub-control levels with triptolide (20-1000 ng/ml). Our results support that sputum in bronchiectasis can stimulate IL-6 production from NHBE cells, and TNF-alpha is an important cytokine mediating the process. The suppressive effects observed with ibuprofen, triptolide and MK-663 warrant further study.

Anti-Inflammatory Agents↗
PubMed2004

Psychological responses to the SARS outbreak in healthcare students in Hong Kong.

This paper reports a cross-sectional questionnaire study that investigated perceived stress and psychological responses to the SARS outbreak in healthcare students at the height of the outbreak in Hong Kong in 2003. Non-healthcare university students served as controls. All the groups reported high levels of perceived stress. Despite being similarly confident in infection control procedures, nursing students were significantly more stressed than medical students, possibly reflecting a perceived higher risk of infection due to more prolonged contact with patients. Non-healthcare students also had high stress levels due to the perceived risks of dying from SARS, reflecting a fear of the unknown. Suitable psychological and occupational support services should be made available in case of future outbreaks.

Chi-Square Distribution↗
PubMed2004

Severe acute respiratory syndrome: temporal lung changes at thin-section CT in 30 patients.

PURPOSE: To evaluate lung abnormalities on serial thin-section computed tomographic (CT) scans in patients with severe acute respiratory syndrome (SARS) during acute and convalescent periods. MATERIALS AND METHODS: Serial thin-section CT scans in 30 patients (17 men, aged 42.5 years +/- 12.2 [SD]) with SARS were reviewed by two radiologists together for predominant patterns of lung abnormalities: ground-glass opacities, ground-glass opacities with superimposed linear opacities, consolidation, reticular pattern, and mixed pattern (consolidation, ground-glass opacities, and reticular pattern). Scans were classified according to duration in weeks after symptom onset. Longitudinal changes of specific abnormalities were documented in 17 patients with serial scans obtained during 3 weeks. Each lung was divided into three zones; each zone was evaluated for percentage of lung involvement. Summation of scores from all six lung zones provided overall CT score (maximal CT score, 24). RESULTS: Median CT scores increased from 1 in the 1st week to 12.5 in the 2nd week. Ground-glass opacities with or without smooth interlobular septal thickening and consolidation were predominant patterns found during the 1st week. Ground-glass opacities with superimposed irregular reticular opacities, mixed pattern, and reticular opacities were noted from the 2nd week and peaked at or after the 4th week. After the 4th week, 12 (55%) of 22 patients had irregular linear opacities with or without associated ground-glass opacities and CT scores greater than 5; five of these patients had bronchial dilatation. When specific opacities were analyzed in 17 patients, consolidation generally resolved completely (n = 4) or to minimal residual opacities; six (55%) of 11 patients with ground-glass opacities had substantial residual disease (CT scores > 5) on final scans. CONCLUSION: There is a temporal pattern of lung abnormalities at thin-section CT in SARS. Predominant findings at presentation are ground-glass opacities and consolidation. Reticulation is evident after the 2nd week and persists in half of all patients evaluated after 4 weeks. Long-term follow-up is required to determine whether the reticulation represents irreversible fibrosis.

Adult↗
PubMed2004

Stress and psychological impact on SARS patients during the outbreak.

OBJECTIVE: To examine stress and psychological impact in severe acute respiratory syndrome (SARS) patients during the 2003 outbreak. SARS is a novel, highly infectious pneumonia, and its psychological impact is still unclear. METHOD: At the peak of the outbreak, SARS patients (n = 79) and healthy control subjects (n = 145) completed the Perceived Stress Scale (PSS) and documented a range of psychological responses. Groups were balanced for age, sex, education, and living circumstances. RESULTS: Stress was significantly higher in SARS patients than in healthy control subjects. Stress correlated significantly with negative psychological effects. Of SARS patients, 39% (n = 30) were infected health care workers; these individuals reported significantly more fatigue and worries about health than did other patients. Of patients, 25% (n = 20) requested psychological follow-up. CONCLUSIONS: General stress and negative psychological effects are increased in SARS patients, particularly among infected health care workers. This may increase the risk of mood and stress-related disorders. Functional impairment is apparent in the postrecovery phase.

Adolescent↗
PubMed2004

Psychological effects of the SARS outbreak in Hong Kong on high-risk health care workers.

OBJECTIVE: To quantify stress and the psychological impact of severe acute respiratory syndrome (SARS) on high-risk health care workers (HCWs). METHOD: We evaluated 271 HCWs from SARS units and 342 healthy control subjects, using the Perceived Stress Scale (PSS) to assess stress levels and a structured list of putative psychological effects of SARS to assess its psychological effects. Healthy control subjects were balanced for age, sex, education, parenthood, living circumstances, and lack of health care experience. RESULTS: Stress levels were raised in both groups (PSS = 18) but were not relatively increased in the HCWs. HCWs reported significantly more positive (94%, n = 256) and more negative psychological effects (89%, n = 241) from SARS than did control subjects. HCWs declared confidence in infection-control measures. CONCLUSIONS: In HCWs, adaptive responses to stress and the positive effects of infection control training may be protective in future outbreaks. Elevated stress in the population may be an important indicator of future psychiatric morbidity.

Adult↗
PubMed2004

High-resolution CT findings of severe acute respiratory syndrome at presentation and after admission.

OBJECTIVE: The aim of this study was to assess the high-resolution CT (HRCT) findings at presentation and after hospital admission in patients with severe acute respiratory syndrome (SARS). MATERIALS AND METHODS: We reviewed the HRCT findings at presentation (n = 12) and after hospital admission (n = 25) of 29 patients with SARS and compared the HRCT findings with the radiographic findings. HRCT scans were obtained using 1-mm (n = 28) or 2-mm (n = 1) collimation. The radiographs and HRCT scans were reviewed independently by two observers who reached a decision by consensus. RESULTS: All patients had abnormal findings on HRCT at presentation. Eight of these 12 patients had normal findings on radiographs. The predominant HRCT findings at presentation consisted of unilateral (n = 6) or bilateral (n = 2) ground-glass opacities or focal unilateral (n = 2) or bilateral (n = 2) areas of consolidation. All patients showed progression of disease on follow-up. The predominant HRCT findings on follow-up CT scans consisted of unilateral (n = 2) or bilateral ground-glass opacities (n = 13), unilateral (n = 2) or bilateral consolidation (n = 5), or a mixed bilateral pattern of ground-glass attenuation, consolidation, and reticulation (n = 3). Reticulation with associated architectural distortion and mild traction bronchiectasis was present in eight patients. CONCLUSION: HRCT can show parenchymal abnormalities in patients with SARS who have normal findings on radiographs at presentation. Follow-up CT scans obtained in hospitalized patients show findings consistent with fibrosis in a small percentage of patients.

Adult↗
PubMed2003

Using biofunctional magnetic nanoparticles to capture vancomycin-resistant enterococci and other gram-positive bacteria at ultralow concentration.

Covalently linked to vancomycin (Van), chemically stable and highly magnetic anisotropic FePt magnetic nanoparticles (3-4 nm) become water-soluble and capture vancomycin-resistant enterococci (VRE) and other Gram-positive bacteria at concentrations approximately 10(1) cfu/mL via polyvalent ligand-receptor interactions. When a pyramidal end of a magnet "focuses" the nanoparticles into approximately 1 mm(2) area, the bacteria can be observed by an optical microscope and further identified by electron micrograph (EM). Compared to the conventional use of magnetic particles (with the sizes of 1-5 microm) in biological separation or drug delivery, magnetic nanoparticles, combined with specific receptor-ligand interactions, promise a sensitive and rapid protocol to detect pathogens.

Alloys↗
PubMed2003

Endothelial function in obstructive sleep apnea and response to treatment.

Impaired endothelium-dependent vascular relaxation is a prognostic marker of atherosclerosis and cardiovascular disease. We evaluated endothelium-dependent flow-mediated dilation (FMD) and endothelium-independent nitroglycerin (NTG)-induced dilation of the brachial artery with Doppler ultrasound in 28 men with obstructive sleep apnea (OSA) and 12 men without OSA. Subjects with OSA (apnea-hypopnea index; mean +/- SD, 46.0 +/- 14.5) had lower FMD compared with subjects without OSA (5.3 +/- 1.7% vs. 8.3 +/- 1.0%, p < 0.001), and major determinants of FMD were the apnea-hypopnea index and age. There was no significant difference in NTG-induced dilation. Subjects with OSA were randomized to nasal continuous positive airway pressure (nCPAP) or observation for 4 weeks. Subjects on nCPAP had significant increase in FMD, whereas those on observation had no change (4.4% vs. -0.8%, difference of 5.2%, p < 0.001). Neither group showed significant change in NTG-induced vasodilation. Eight subjects who used nCPAP for over 3 months were reassessed on withdrawing treatment for 1 week. On nCPAP withdrawal, FMD became lower than during treatment (p = 0.02) and were similar to baseline values. Our findings demonstrated that men with moderate/severe OSA have endothelial dysfunction and treatment with nCPAP could reverse the dysfunction; the effect, however, was dependent on ongoing use.

Adult↗
PubMed2003

Severe acute respiratory syndrome: relationship between radiologic and clinical parameters.

PURPOSE: To quantify severity of severe acute respiratory syndrome (SARS) on chest radiographs and to determine its relationship with clinical parameters. MATERIALS AND METHODS: Forty patients (mean age, 42.90 years +/- 14.01 [SD]; median age, 41.5 years; age range, 25-82 years) with clinically diagnosed SARS were evaluated. Heart rate, oxygen saturation, temperature, and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were recorded daily. Severity of lung changes on chest radiographs was scored according to percentage of involved lung. Radiographic scores at days of admission, treatment, and maximal radiographic score were extracted for statistical analysis with clinical parameters. Time to maximal radiographic score from admission and days between onset and beginning of treatment were determined. Correlations between radiographic and clinical parameters were evaluated with Spearman rank correlation. Sex differences with respect to clinical and radiographic parameters were evaluated with Mann-Whitney test. RESULTS: Median chest radiographic scores peaked 5 days after beginning of treatment before they declined. Maximal and treatment radiographic scores were inversely related to oxygen saturation (r = -0.67, P <.001; r = -0.35, P =.03). Admission radiographic score was correlated with admission AST level (r = 0.53, P =.003); treatment radiographic score, with treatment ALT and AST levels (r = 0.43, P =.007; r = 0.42, P =.019); and time to maximal radiographic score, with AST level at maximal radiographic score (r = -0.45, P =.006), admission radiographic score (r = -0.55, P <.001), treatment radiographic score (r = -0.58, P <.001), and admission ALT and AST levels (r = -0.44, P =.007; r = -0.58, P =.001). Treatment delay was associated with AST level at maximal radiographic score (r = 0.53, P =.001), treatment radiographic score (r = 0.60, P <.001), and time to maximal radiographic score (r = -0.36, P =.02). No sex differences occurred with respect to radiographic and clinical parameters (P >.05). CONCLUSION: Severity of lung abnormalities quantified on chest radiographs correlates with clinical and laboratory parameters.

Adult↗
PubMed2003

In vitro study examining the effect of sub-lethal QS 755 nm lasers on the expression of p16INK4a on melanoma cell lines.

BACKGROUND AND OBJECTIVES: Q-switched lasers had been used in the treatment of lentigo maligna but their role remains controversial. While previous studies have addressed the change in adhesion molecule expression after sub-lethal laser damage, no study has addressed the impact of sub-lethal laser damage at a molecular level. The p16 gene has been proposed as the candidate gene for melanoma. Our objective is to examine the effect of sub-lethal laser damage on p16 expression in melanoma cell lines. STUDY DESIGN/MATERIALS AND METHODS: Three human melanoma cell lines-HTB 66, Sk-mel-24 (HTB 71), and G361-were irradiated by a Q-switched 755 nm Alexandrite laser at fluencies that ranged from 0.85 to 2.0 J/cm(2). HTB 66 was the only cell line with significant expression of p16INK4a while the other two cells lines were p16INK4a negative and served as negative control. Protein and mRNA expression for p16 were assessed by flow cytometry and RT-PCR, respectively. RESULTS: The level of p16INK4a protein in cell line HTB 66 increased significantly after laser irradiation as compared with non-irradiated cells. The level of p16INK4a protein did not change in p16INK4a-negative cell lines (Sk-mel-24 and G361). However, there was only a slight increase in the percentage of G0/G1 phase cells. CONCLUSIONS: Sub-lethal laser damage could increase DNA damage leading to an increase in p16 expression, and such effect would be particularly undesirable for patients with p16 mutation. Further studies are warranted to examine the role of sub-lethal laser damage in inducing p16 mutation.

Analysis of Variance↗
PubMed2003

Silicosis in 76 men: qualitative and quantitative CT evaluation--clinical-radiologic correlation study.

PURPOSE: To use qualitative and quantitative computed tomography (CT) to test the hypothesis that impaired lung function with silicosis is due to progressive massive fibrosis (PMF) and associated emphysema. MATERIALS AND METHODS: Seventy-six men with silicosis underwent volumetric and thin-section CT of the thorax. Lung function, Borg scale dyspnea grade, silica exposure duration, and cigarette consumption were determined. Nodular profusion (NP) at chest radiography was graded according to the International Labor Organization radiographic classification system; NP and PMF at CT were visually graded by using five-point (ie, grades 0-4) and four-point (grades 0-3) scales, respectively. Emphysema and NP, which together are defined as the NP index, were quantified by using attenuation threshold values of less than -950 HU and greater than -100 HU, respectively. Mean lung attenuation was also determined. Relationships among the CT, chest radiographic, and clinical parameters were analyzed by using Spearman correlation. RESULTS: NP at chest radiography correlated (r > 0.50) with all CT parameters of nodularity. CT PMF had the highest correlation with emphysema (r = 0.58, P <.001). NP at chest radiography and all CT parameters were inversely related to lung function. At multiple regression analysis, PMF and emphysema index (both at CT) were significant determinants of forced expiratory volume in 1 second (FEV1) (P =.006 and.03, respectively) and FEV1 to forced vital capacity (FVC) ratio (P =.007 and.02, respectively). Mean lung attenuation remained related to FVC (P =.03), diffusing capacity of lung for carbon monoxide (P =.04), and Borg scale grade (P =.01). Cigarette consumption and silica exposure duration had no independent effects on lung function. CONCLUSION: Qualitative and quantitative CT parameters can be used as indirect measures of functional impairment in silicosis. PMF and emphysema are independently related to airflow obstruction, whereas mean lung attenuation is related to clinical dyspnea and reduced lung volume.

Adult↗
PubMed2003

Beta-thalassemia major: thin-section CT features and correlation with pulmonary function and iron overload.

PURPOSE: To describe and quantify thin-section computed tomographic (CT) features of the lung in patients with beta-thalassemia major (beta-TM) and determine the correlation between thin-section CT findings, pulmonary function test (PFT) results, and iron overload. MATERIALS AND METHODS: Forty-one patients with beta-TM (mean age, 24.5 years) underwent thin-section CT (during full inspiration and expiration) and PFTs. Two radiologists in consensus recorded the presence of focal bronchial and parenchymal abnormalities and air trapping. A semiquantitative air trapping score (ATS) was used, and patients were separated into air trapping-negative (ATS between 0 and 3) and air trapping-positive (ATS > 3) groups for statistical analysis. Iron overload was estimated by calculating the ratio of the signal intensity (SI) of the liver to the SI of paraspinous muscle by using magnetic resonance imaging in 27 patients (66%). We performed multiple logistic regression analysis to study the influence of age, PFT findings, and SI ratio on the presence of air trapping at CT and multivariate regression analysis to study the simultaneous influence of the presence of air trapping on obstructive PFT indexes. RESULTS: Air trapping was the predominant thin-section CT finding and was seen in 10 (24%) of 41 patients. No patient had interstitial lung disease at CT, although 11 (27%) had a restrictive spirometric pattern. Simple logistic regression analysis revealed significant associations between ATS and forced expiratory volume in the first second (FEV1), FEV1/forced vital capacity (FVC), forced expiratory flow (FEF) in the midexpiratory phase (FEF25%-75%), FEF at 50% of the FVC (FEF50%), and FEF at 75% of the FVC (FEF75%) (P =.019,.030,.007,.034, and.021, respectively) but not between ATS and SI ratio. At multiple logistic regression analysis, only FEF25%-75% was significantly associated with ATS (P =.019, adjusted odds ratio = 0.86, R2 = 41.8%). Multivariate analysis revealed that ATS did not have a significant influence on lung function indexes (P =.104), although significant effects were found with FEV1, FEF25%-75%, FEF50%, and FEF75% when examined separately. CONCLUSION: Air trapping may be present at expiratory thin-section CT in patients with beta-TM and is associated with reduced FEF25%-75% values but not hepatic iron overload.

Adolescent↗