Interstitial lung disease in systemic sclerosis: An HRCT-clinical correlative study

Purpose: To evaluate high-resolution CT (HRCT) parameters of inflammation and fibrosis in systemic sclerosis (SSc), for correlation with lung function, skin scores and exercise tolerance.

Material and Methods: 45 SSc patients (40 women, 48.5±13.4 years), underwent thoracic HRCT, lung function assessment, and modified Rodnan skin scores. Exercise tolerance was also graded. HRCT were scored for extent of 4 HRCT patterns of interstitial lung disease (ILD): ground glass opacification (GGO), reticular, mixed and honeycomb pattern in each lobe. Total HRCT score, inflammation index (GGO and mixed score) and fibrosis index (reticular and honeycomb scores) were correlated with lung function and clinical parameters.

Results: ILD was present in 39/45 (86.7%) patients. Abnormal (<80% predicted) forced vital capacity (FVC), total lung capacity (TLC) and carbon monoxide diffusion factor (DLco) were detected in 30%, 22% and 46% of patients. Total HRCT score correlated with FVC ( r=−0.43, p=0.008), FEV1 (forced expiratory volume) ( r=–0.37, p=0.03), TLC ( r=–0.47, p=0.003), and DLCO ( r=–0.43, p=0.008); inflammatory index with DLCO ( r=–0.43, p=0.008) and exercise tolerance ( r=–0.39, p < 0.05); and fibrosis index with FVC ( r=–0.31, p=0.05) and TLC ( r=–0.38, p=0.02). Higher total HRCT score, and inflammation and fibrosis indices were found in patients with abnormal lung function.

Conclusion: Qualitative HRCT is able to evaluate inflammation and fibrosis, showing important relationships with diffusion capacity and lung volume, respectively.

Detection and characterisation of extended-spectrum beta-lactamases among blood stream isolates of Enterobacter species in Hong Kong

1. Extended-spectrum beta-lactamase(ESBL) resistance in Enterobacter spp may be under-recognised. 2. Detection methods for ESBL resistance in Enterobacter spp may need to be modified.

Antimicrobial resistance in Escherichia coli outpatient urinary isolates from women: emerging multidrug resistance phenotypes

This study evaluated the antimicrobial resistance profile of outpatient urinary Escherichia coli isolated from women obtained throughout Hong Kong during 2004-2005. Of 1067 single patient isolates analyzed, 60.1% were resistant to ampicillin, 34% were resistant to co-trimoxazole, and 22.1% were resistant to ciprofloxacin. Thirty-four (6.6%) of 519 isolates in 2004 and 55 (10%) of 548 isolates in 2005 were extended-spectrum beta-lactamase (ESBL) producers with a CTX-M phenotype. Rates of non-beta-lactam resistance and ESBL production were strongly influenced by patient age. The age-stratified rates for dual co-trimoxazole and ciprofloxacin resistance and for ESBL production were 10.9% and 7.6% in women aged 18-35 years, 13% and 6.9% in women aged 36-50 years, 20.4% and 8.8% in women aged 51-64 years, and 23.7% and 11.8% in women aged > or =65 years, respectively. Nitrofurantoin and fosfomycin remain active against >90% of the isolates, irrespective of the resistance phenotypes for other drugs. Our results documented the emergence of problematic resistance phenotypes among community urinary E. coli and highlight the need to explore strategies for their containment.

Community emergence of CTX-M type extended-spectrum β-lactamases among urinary Escherichia coli from women

OBJECTIVES

To conduct a territory-wide study of extended-spectrum beta-lactamases (ESBLs) among community isolates of urinary Escherichia coli from women in Hong Kong.

METHODS

Up to 50 consecutive single-patient E. coli isolates, collected from 13 laboratories in 2004, were studied. The ESBLs were characterized by PCR sequencing using specific primers. The epidemiological relationship of the isolates was studied by PFGE and phylogenetic group PCRs.

RESULTS

Forty-two ESBL producers were found among 600 consecutive isolates tested. The ESBL prevalence was 7.3% (15/205) for women aged 18-35 years, 5% (11/219) for women aged 36-50 years, 6.3% (4/63) for women aged 51-64 years and 10.6% (12/113) for women aged >or=65 years (P=0.3). The ESBL-producing isolates were often multidrug-resistant and CTX-M-14 was found in 37 isolates, CTX-M-15 in 3 isolates and CTX-M-3 in 2 isolates. PFGE revealed no significant clusters among the ESBL producers. Overall, CTX-M-14 producers were significantly more likely to belong to group D than non-ESBL producers [18/37 (48.6%) versus 13/57 (22.8%), P=0.009]. However, 7 of 13 (53.8%) CTX-M-14 producers from women aged 18-35 years represented phylogenetic group B2, compared with 7 of 24 (29.2%) for women of all other ages (P=0.1).

CONCLUSIONS

The study documented the community emergence of CTX-M as the predominant ESBL type among urinary isolates from women. The spread of CTX-M enzymes among isolates from young women is concerning and deserves close monitoring.

Immediate and sustained psychological impact of an emerging infectious disease outbreak on health care workers

OBJECTIVE

To assess the immediate and sustained psychological health of health care workers who were at high risk of exposure during the severe acute respiratory syndrome (SARS) outbreak.

METHODS

At the peak of the 2003 SARS outbreak, we assessed health care workers in 2 acute care Hong Kong general hospitals with the Perceived Stress Scale (PSS-10). One year later, we reassessed these health care workers with the PSS-10, the 21-Item Depression and Anxiety Scale (DASS-21), and the Impact of Events Scale-Revised (IES-R). We recruited high-risk health care workers who practised respiratory medicine and compared them with nonrespiratory medicine workers, who formed the low-risk health care worker control group.

RESULTS

In 2003, high-risk health care workers had elevated stress levels (PSS-10 score = 17.0) that were not significantly different from levels in low-risk health care worker control subjects (PSS-10 score = 15.9). More high-risk health care workers reported fatigue, poor sleep, worry about health, and fear of social contact, despite their confidence in infection-control measures. By 2004, however, stress levels in the high-risk group were not only higher (PSS-10 score = 18.6) but also significantly higher than scores among low-risk health care worker control subjects (PSS-10 score = 14.8, P < 0.05). In 2004, the perceived stress levels in the high-risk group were associated with higher depression, anxiety, and posttraumatic stress scores (P < 0.001). Posttraumatic stress scores were a partial mediator of the relation between the high risk of exposure to SARS and higher perceived stress.

CONCLUSIONS

Health care workers who were at high risk of contracting SARS appear not only to have chronic stress but also higher levels of depression and anxiety. Front-line staff could benefit from stress management as part of preparation for future outbreaks.

Stress and psychological distress among SARS survivors 1 year after the outbreak

OBJECTIVE

Our study examined the stress level and psychological distress of severe acute respiratory syndrome (SARS) survivors 1 year after the outbreak.

METHOD

During the SARS outbreak in 2003, we used the 10-item Perceived Stress Scale (PSS-10) to assess SARS survivors treated in 2 major hospitals (non-health care workers, n = 49; health care workers, n = 30). We invited SARS survivors from the same hospitals (non-health care workers, n = 63; health care workers, n = 33) to complete the PSS-10 again in 2004. At that time, they were also asked to complete the General Health Questionnaire (GHQ-12) and measures of depression, anxiety, and posttraumatic symptoms. PSS-10 scores were also obtained from matched community control subjects during the outbreak (n = 145) and again in 2004 (n = 112).

RESULTS

SARS survivors had higher stress levels during the outbreak, compared with control subjects (PSS-10 scores = 19.8 and 17.9, respectively; P < 0.01), and this persisted 1 year later (PSS-10 scores = 19.9 and 17.3, respectively; P < 0.01) without signs of decrease. In 2004, SARS survivors also showed worrying levels of depression, anxiety, and posttraumatic symptoms. An alarming proportion (64%) scored above the GHQ-12 cut-off that suggests psychiatric morbidity. During the outbreak, health care worker SARS survivors had stress levels similar to those of non-health care workers, but health care workers showed significantly higher stress levels in 2004 (PSS-10 score = 22.8, compared with PSS-10 score = 18.4; P < 0.05) and had higher depression, anxiety, posttraumatic symptoms, and GHQ-12 scores.

CONCLUSIONS

One year after the outbreak, SARS survivors still had elevated stress levels and worrying levels of psychological distress. The situation of health care worker SARS survivors is particularly worrying. The long-term psychological implications of infectious diseases should not be ignored. Mental health services could play an important role in rehabilitation.

Clinical outcomes of bacteremic pneumococcal infections in an area with high resistance

In a retrospective study designed to gather information in a region with high antimicrobial resistance, the outcomes of 216 episodes of laboratory-confirmed pneumococcal bacteremia treated in Hong Kong between 1995 and 2001 were assessed. The patients had a mean age (+/-standard deviation) of 40+/-33.7 years. In all patients, the clinical diagnosis was confirmed by isolation of Streptococcus pneumoniae from blood (n=216), cerebrospinal fluid (n=7) and/or other sterile sites (n=12). Penicillin nonsusceptibility was found in 37.5% of the isolates (20.8% intermediate and 16.7% resistant). Penicillin nonsusceptibility was not a risk factor for inpatient mortality (p=0.7), nor did it affect duration of fever (p=0.4), requirement for intensive care unit admission (p=0.4) or development of suppurative complications (p=0.2). Advanced age (OR 11.3, 95%CI 4.5-28.2, p<0.01), critical illness (OR 11.3, 95%CI 4.5-28.2, p<0.001) and discordant therapy (OR 4.3, 95%CI 1.7-10.9, p<0.002) involving agents with poor anti-pneumococcal activity (but not penicillins and broad-spectrum beta-lactam agents) were significantly associated with mortality.

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.

Elevated levels of transforming growth factor-β1 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.

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.

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.

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.

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.

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.

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.

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.

Increased adrenomedullin expression in lungs in endotoxaemia

Adrenomedullin (AM) is a peptide involved in cardiovascular homeostasis and in inflammation. We examined its expression in a rat model of endotoxaemia. Male Sprague-Dawley rats received intraperitoneal injection of 5 or 10 mg/kg lipopolysaccharide (LPS), or saline as control. Rats were killed at 1, 3, 6, 12 and 24 h after injection. LPS at 5 mg/kg, but not saline, increased plasma AM significantly at 3 h. At 10 mg/kg, plasma AM was raised at 3, 6 and 12 h. Immunoreactive AM concentration in lung increased after 5 or 10 mg/kg LPS, but not saline. PreproAM mRNA level in lung was significantly increased at 3 and 6 h. In conclusion, endotoxin stimulates the expression of AM in the lungs and increases its circulatory concentration. AM may be involved in the systemic response to sepsis.

Prolonged disturbances of in vitro cytokine production in patients with severe acute respiratory syndrome (SARS) treated with ribavirin and steroids

Severe acute respiratory syndrome (SARS) is a new disease which has spread rapidly and widely. We wished to know whether evaluation of in vitro cytokine production could contribute to improved understanding of disease pathogenesis and to better patient management. Numbers of unstimulated and mitogen-stimulated cytokine-secreting peripheral blood mononuclear cells were measured repeatedly during and after hospitalization in 13 patients with SARS using enzyme-linked immunospot technology. Numbers of interferon-gamma, interleukin (IL)-2, IL-4, IL-10 and IL-12 secreting cells induced by T cell activators were below normal in many or most patients before and during treatment with corticosteroids and ribavirin but returned essentially to normal after completion of treatment. Staphylococcus aureus Cowan 1 (SAC)-stimulated IL-10 secreting cells were increased in early SARS but fell during treatment. SAC-induced IL-12 secreting cells were deficient before, during and long after treatment. Numbers of cells induced to produce IL-6 and tumour necrosis factor-alpha by T cell or monocyte activators were higher than normal in many early SARS patients and were still increased in some during and after treatment. We conclude that prolonged dysregulated cytokine production occurs in SARS and that future studies should be directed at improving anti-inflammatory and antiviral therapies in order to limit cytokine impairment.

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.

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.

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.

The relationship between mediastinal lymph node attenuation with parenchymal lung parameters in silicosis

OBJECTIVE

Attenuation changes on computed tomography (CT) in mediastinal lymph nodes (LN) may be related to lung alterations and functional impairment in silicosis.

DESIGN

CT and clinical data of 41 (64.2 +/- 8.3 years) males with silicosis were retrieved. Attenuation type (calcified, hyperdense, normodense) and calcification pattern (central, eccentric, dense, eggshell, speckled) of mediastinal LN were evaluated; LN attenuation of uncalcified LNs quantified on CT in six LN stations. Nodular profusion (CT-NP) and progressive massive fibrosis (CT-PMF) were graded. Relationships between LN, CT, lung function and clinical parameters were determined.

RESULTS

LN sites were paratracheal (n = 39), subcarinal (n = 39), tracheobronchial (n = 37), aortopulmonary (n = 37), hilar (n = 27), and peri-oesophageal (n = 21). LNs were calcified, hyperdense and normodense in 107, 85 and 54 LN stations, respectively. Uniformly calcified LN was most common, followed by speckled calcification. Central, eccentric and eggshell calcification was rare. CT-NP scores > or = 16 were associated with higher LN attenuation and number of calcified LN stations than CT-NP scores < 16. PMF had no influence over LN morphology or calcification pattern. LN attenuation correlated with CT-PMF (r = 0.36, P = 0.01), CT-NP (r = 0.54, P < 0.001) and DLCO/VA (r = -0.33, P = 0.02).

CONCLUSION

Uniformly calcified and hyperdense LNs are common in silicosis, and eggshell LN calcification is rare. There are associations between LN attenuation and lung function impairment, and CT grades of nodular profusion and PMF.

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.

Severe acute respiratory syndrome: radiographic evaluation and clinical outcome measures

PURPOSE

To evaluate the relationship among chest radiographs, oxygen supplementation requirement, and treatment response in severe acute respiratory syndrome (SARS).

MATERIALS AND METHODS

Forty patients (20 women, 20 men; mean age, 42.90 years +/- 14.01 [SD]; median age, 41.5 years; age range, 25-82 years) with SARS were evaluated. Daily chest radiographs were graded according to percentage of lung involvement during 20.15 days +/- 5.56 (median, 20 days; range, 14-38 days). Times between symptoms and treatment and time to reach maximal radiographic score from admission and treatment day were determined. Daily oxygen saturation (Sao2) and oxygen supplementation including mechanically assisted ventilation were recorded. Treatment response was defined as good, fair, and poor. Patterns of radiographic opacity at admission and at maximal radiographic score were noted. Differences in radiographic and clinical parameters with respect to oxygen supplementation and treatment response were respectively evaluated with Mann-Whitney and Kruskal-Wallis tests.

RESULTS

Larger maximal radiographic scores, lower Sao2 at maximal radiographic change, longer time from treatment to maximal radiographic score (P <.01), and diffuse consolidation at maximal radiographic score were associated with oxygen supplementation. Parameters that influenced treatment response were time from symptom onset to treatment day (P =.003), time from admission to treatment day (P <.001), time to maximal radiographic score from treatment day (P =.001), maximal radiographic score (P =.009), Sao2 at maximal radiographic score (P =.13), and treatment radiographic score (P =.03). Fair responders had shorter time between admission and treatment than did either good (P <.001) or poor responders (P =.002) and shorter time between symptoms and treatment (P <.001) and lower treatment radiographic score (P =.012) than did good responders. Good (82%), poor (36%), and fair (33%) responders developed maximal chest radiographic scores within 4 days of treatment (P =.008). Radiographic patterns at both admission and maximal radiographic score did not influence treatment response.

CONCLUSION

There are significant relationships among radiographic parameters, oxygen supplementation, and treatment response, and these relationships appear to be clinically useful in the treatment of SARS.

β-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.

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.

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.

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.

Using biofunctional magnetic nanoparticles to capture gram-negative bacteria at an ultra-low concentration

After conjugation to vancomycin (Van), chemically stable and highly magnetic anisotropic FePt magnetic nanoparticles (approximately 4 nm) become water-soluble and capture E. coli at 15 cfu mL(-1).

Lymphoepithelioma-like carcinoma of the lung in a patient with silicosis

Silicosis is an important form of pneumoconiosis, which is caused by significant exposure to crystalline silica. The carcinogenicity of silica, despite traditional beliefs, in relation to lung cancer has been controversial. Lymphoepithelioma-like carcinoma of the lung, an Epstein-Barr virus-associated undifferentiated carcinoma, is a rare entity of pulmonary malignancy, which tends to affect young nonsmoking Asians. The first case of silicosis, initially complicated by pulmonary tuberculosis, which later developed into advanced lymphoepithelioma-like carcinoma of the lung is reported. A combination of 5-fluorouracil, cisplatin and calcium folinate resulted in partial tumour response.

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.

A multicenter phase II study of the efficacy and safety of docetaxel plus cisplatin in Asian chemonaïve patients with metastatic or locally advanced non-small cell lung cancer

AIMS

To evaluate the efficacy and safety of docetaxel-cisplatin in patients with metastatic or locally advanced non-small cell lung cancer (NSCLC).

METHODS

Chemotherapy-naïve patients with histologically confirmed TNM stage III or IV NSCLC were recruited from 12 Asian trial centers. Patients received docetaxel (75 mg/m2) and cisplatin (75 mg/m2) every 3 weeks for 6 cycles.

RESULTS

130 of 146 patients were evaluable for efficacy (60% stage IV). Three complete and 58 partial responses were observed (overall response rate: 46.9%; 95% CI: 38.3-55.5%). Median time to progression was 6.9 months and median survival was 14.0 months; 1-year survival was 59.5%. Grade 3/4 neutropenia, thrombocytopenia and anemia occurred in 69.2%, 6.2% and 18.5% of patients, respectively. Grade 3/4 vomiting was observed in 13.7% and grade 3/4 neurosensory effects were observed in 2.7% of patients. There was one case of treatment-related death due to sepsis.

CONCLUSION

Docetaxel-cisplatin is an effective and well-tolerated treatment in Asian patients with NSCLC.

Interstitial lung disease in systemic sclerosis

PURPOSE

To evaluate high-resolution CT (HRCT) parameters of inflammation and fibrosis in systemic sclerosis (SSc), for correlation with lung function, skin scores and exercise tolerance.

MATERIAL AND METHODS

45 SSc patients (40 women, 48.5+/-13.4 years), underwent thoracic HRCT, lung function assessment, and modified Rodnan skin scores. Exercise tolerance was also graded. HRCT were scored for extent of 4 HRCT patterns of interstitial lung disease (ILD): ground glass opacification (GGO), reticular, mixed and honeycomb pattern in each lobe. Total HRCT score, inflammation index (GGO and mixed score) and fibrosis index (reticular and honeycomb scores) were correlated with lung function and clinical parameters.

RESULTS

ILD was present in 39/45 (86.7%) patients. Abnormal (<80% predicted) forced vital capacity (FVC), total lung capacity (TLC) and carbon monoxide diffusion factor (DLco) were detected in 30%, 22% and 46% of patients. Total HRCT score correlated with FVC (r=-0.43, p=0.008), FEV1 (forced expiratory volume) (r=-0.37, p=0.03), TLC (r=-0.47, p=0.003), and DLCO (r=-0.43, p=0.008); inflammatory index with DLCO (r=-0.43, p=0.008) and exercise tolerance (r=-0.39, p < 0.05); and fibrosis index with FVC (r=-0.31, p=0.05) and TLC (r=-0.38, p=0.02). Higher total HRCT score, and inflammation and fibrosis indices were found in patients with abnormal lung function.

CONCLUSION

Qualitative HRCT is able to evaluate inflammation and fibrosis, showing important relationships with diffusion capacity and lung volume, respectively.

Computed tomography characteristics of advanced primary pulmonary lymphoepithelioma-like carcinoma

Our objectives were to document CT features of advanced primary pulmonary lymphoepithelioma-like carcinoma (LELC) and to determine features that may assist differentiation from other non-small cell lung cancers (NSCLC). Imaging and clinical data of all patients with biopsy-proven pulmonary LELC ( n=12) were retrieved from a database of all NSCLC patients over a 2-year period. Twenty-five controls were recruited from other inoperable non-LELC NSCLC patients from the database. Pre-treatment CT scans of the thorax of both study and control patients were reviewed for lobe involved; tumour site, borders and size; and pleural, vascular or pulmonary involvement. Presence of lymphangitis carcinomatosis was noted. Lymph node metastasis was characterised as ipsilateral or contralateral enlarged (>1 cm) mediastinal or hilar nodes, or as peribronchovascular nodal spread. Differences between the two groups were tested using Mann-Whitney rank-sum test. The LELC tumours were significantly larger (45.67 vs 17.71 cm(2)) than controls and were closely associated with the mediastinum. There were more LELC tumours with well-defined borders ( p<0.001) and fewer with spiculated borders ( p<0001) than non-LELC tumours. There was increased peribronchovascular nodal spread ( p=0.01) and vascular encasement ( p=0.02) in LELC compared with non-LELC tumours. Advanced primary pulmonary LELC has distinct radiological features, and can appear as well-defined tumour closely associated with the mediastinum, with peribronchovascular spread and vascular encasement.

Bacteremia caused by Escherichia coli producing extended-spectrum beta-lactamase: a case-control study of risk factors and outcomes

A case-control study was conducted in order to identify the risk factors associated with bloodstream infection caused by Escherichia coli producing extended-spectrum beta-lactamase (ESBL) and to determine the outcomes of infected patients. Risk factors associated with ESBL production, according to univariate analysis, included a history of recent hospitalization [odds ratio (OR) 4.3, 95% confidence interval (CI) 2.1-8.9; p < 0.001], severe underlying diseases (OR 15, 95% CI 4.4-51.5; p < 0.001), prior exposure to urinary catheters (OR 8.3, 95% CI 3.2-21.7; p < 0.001) and nosocomial (OR 14.1, 95% CI 6.1-32.8; p < 0.001) or urinary (OR 3.6, 95% CI 1.7-7.4; p < 0.001) origin of the bacteria. Multivariate analysis revealed that severe underlying diseases (OR 31.2, 95% CI 6.7-144; p < 0.001) and nosocomial (OR 16.5, 95% CI 5.6-49; p < 0.001) and urinary origins (OR 7.8, 95% CI 2.6-23.8; p < 0.001) of the bacteria were independently associated with ESBL production in bacteremic E. coli. Crude mortality in case patients was more than twice as high as that in controls (p = 0.04). Production of ESBL increased the risk of inappropriate initial therapy (OR 95.6, 95% CI 27.4-334.2; p < 0.001). Treatment failed in 4/7 case patients treated with ceftazidime to which the isolate was susceptible in vitro. Our findings have implications for the choice of empirical therapy in nosocomial urinary tract infection.

High-resolution CT quantification of bronchiectasis: clinical and functional correlation

PURPOSE

To evaluate clinical relevance of high-resolution computed tomographic (CT) findings in patients with bronchiectasis by using a quantitative high-resolution CT protocol to assess extent of bronchiectasis, severity of bronchial wall thickening, and presence of small-airway abnormalities and mosaic pattern.

MATERIALS AND METHODS

Sixty Chinese patients with steady-state bronchiectasis underwent thoracic high-resolution CT and lung function tests. Exacerbation frequency per year and 24-hour sputum volume were determined. Extent of bronchiectasis, severity of bronchial wall thickening, and presence of small-airway abnormalities and mosaic attenuation were evaluated in each lobe, including the lingula. Differences between sex and smoking status with respect to high-resolution CT, lung function, and clinical parameters were tested with either the independent sample t test or the Mann-Whitney test. Spearman rank correlation was used to evaluate associations between clinical, lung function, and high-resolution CT scores. Multiple regression analyses were performed to determine which high-resolution CT parameters would best predict lung function and clinical parameters, adjusted for smoking.

RESULTS

Exacerbation frequency was associated with bronchial wall thickening (r = 0.32, P =.03); 24-hour sputum volume with bronchial wall thickening and small-airway abnormalities (r = 0.30 and 0.39, respectively; P <.05); and forced expiratory volume in 1 second (FEV(1)), ratio of FEV(1) to forced vital capacity (FVC), and midexpiratory phase of forced expiratory flow (FEF(25%-75%)) (r = -0.33, -0.29, and -0.32, respectively; P <.05). Extent of bronchiectasis, bronchial wall thickening, and mosaic attenuation, respectively, were related to FEV(1) (r = -0.43 to -0.60, P <.001), FEF(25%-75%) (r = -0.38 to -0.57, P <.001), FVC (r = -0.36 to -0.46, P <.01), and FEV(1)/FVC ratio (r = -0.31 to -0.49, P <.01). After multiple regression analysis, bronchial wall thickening remained a significant determinant of airflow obstruction, whereas small-airway abnormalities remained associated with 24-hour sputum volume. Women had milder disease than men but showed more high-resolution CT functional correlations.

CONCLUSION

Findings of this study establish a link between morphologic high-resolution CT parameters and clinical activity and emphasize the role of bronchial wall thickening in patients with bronchiectasis.

Pulmonary iron overload in thalassemia major presenting as small airway disease

Lung function abnormalities that are associated with thalassemia major are variable with etiology that is yet undetermined. Some studies have suggested that pulmonary iron deposition is a probable cause for these lung defects although there has been no antemortem histopathological and radiological evidence for this. We report a case of thalassemia major with biopsy-proven pulmonary iron overload, in which thoracic high-resolution computed tomography revealed a morphological-functional correlation consistent with small airway disease.

Normal 24-hour ambulatory proximal and distal gastroesophageal reflux parameters in Chinese

OBJECTIVE

To quantify normal proximal and distal oesophageal acid parameters in healthy Chinese.

DESIGN

Observational study.

SETTING

University teaching hospital, Hong Kong.

SUBJECTS AND METHODS

Twenty healthy adults who were not on medication and were free from gastrointestinal symptoms were recruited by advertisement. Ambulatory oesophageal acid (pH<4) exposure parameters were recorded at distal and proximal sites, 5 and 20 cm, respectively above the lower oesophageal sphincter.

RESULTS

The 95th percentile for reflux parameters assessed in the distal/proximal oesophagus were: percent total time pH<4, 4.6/0.7%; percent upright time pH<4, 7.0/1.1%; percent supine time pH<4, 4.5/0.5%; number of reflux episodes, 73/12; number of reflux episodes with pH<4 for >5 minutes, 4/0; and the longest single acid exposure episode, 11.2/3.0 minutes.

CONCLUSION

Physiological gastroesophageal reflux occurs in healthy Chinese. These initial data provide a preliminary reference range that could be utilised by laboratories studying Chinese subjects.

Obstructive sleep apnea is independently associated with insulin resistance

Epidemiological studies have implicated obstructive sleep apnea (OSA) as an independent comorbid factor in cardiovascular and cerebrovascular diseases. It is postulated that recurrent episodes of occlusion of upper airways during sleep result in pathophysiological changes that may predispose to vascular diseases. Insulin resistance is a known risk factor for atherosclerosis, and we postulate that OSA represents a stress that promotes insulin resistance, hence atherogenesis. This study investigated the relationship between sleep-disordered breathing and insulin resistance, indicated by fasting serum insulin level and insulin resistance index based on the homeostasis model assessment method (HOMA-IR). A total of 270 consecutive subjects (197 male) who were referred for polysomnography and who did not have known diabetes mellitus were included, and 185 were documented to have OSA defined as an apnea-hypopnea index (AHI) > or =5. OSA subjects were more insulin resistant, as indicated by higher levels of fasting serum insulin (p = 0.001) and HOMA-IR (p < 0.001); they were also older and more obese. Stepwise multiple linear regression analysis showed that obesity was the major determinant of insulin resistance but sleep-disordered breathing parameters (AHI and minimum oxygen saturation) were also independent determinants of insulin resistance (fasting insulin: AHI, p = 0.02, minimum O(2), p = 0.041; HOMA-IR: AHI, p = 0.044, minimum O(2), p = 0.022); this association between OSA and insulin resistance was seen in both obese and nonobese subjects. Each additional apnea or hypopnea per sleep hour increased the fasting insulin level and HOMA-IR by about 0.5%. Further analysis of the relationship of insulin resistance and hypertension confirmed that insulin resistance was a significant factor for hypertension in this cohort. Our findings suggest that OSA is independently associated with insulin resistance, and its role in the atherogenic potential of sleep disordered breathing is worthy of further exploration.