Biomedical subjects

Mary S M Ip

Publications and source records attributed to Mary S M Ip.

18 recordsLinked to original sources

PubMed2006

Randomised study of three non-surgical treatments in mild to moderate obstructive sleep apnoea.

BACKGROUND: Patients with mild to moderate obstructive sleep apnoea (OSA) may be managed with different treatment options. This study compared the effectiveness of three commonly used non-surgical treatment modalities. METHODS: Subjects with mild to moderate OSA were randomised to one of three treatment groups for 10 weeks: conservative measures (sleep hygiene) only, continuous positive airways pressure (CPAP) in addition to conservative measures or an oral appliance in addition to conservative measures. All overweight subjects were referred to a weight-reduction class. OSA was assessed by polysomnography. Blood pressure was recorded in the morning and evening in the sleep laboratory. Daytime sleepiness was assessed with the Epworth Sleepiness Scale. Health-related quality of life (HRQOL) was assessed with the 36-Item Short-Form Health Survey (SF-36) and Sleep Apnoea Quality of Life Index (SAQLI). RESULTS: 101 subjects with a mean (SEM) apnoea-hypopnoea index (AHI) of 21.4 (1.1) were randomised to one of the three groups. The severity of sleep-disordered breathing was decreased in the CPAP and oral appliance groups compared with the conservative measures group, and the CPAP group was significantly better than the oral appliance group. Relief from sleepiness was significantly better in the CPAP group. CPAP was also better than the oral appliance or conservative measures in improving the "bodily pain" domain, and better than conservative measures in improving the "physical function" domain of SF-36. Both CPAP and the oral appliance were more effective than conservative measures in improving the SAQLI, although no difference was detected between the CPAP and oral appliance groups. CPAP and the oral appliance significantly lowered the morning diastolic blood pressure compared with baseline values, but there was no difference in the changes in blood pressure between the groups. There was also a linear relationship between the changes in AHI and body weight. CONCLUSION: CPAP produced the best improvement in terms of physiological, symptomatic and HRQOL measures, while the oral appliance was slightly less effective. Weight loss, if achieved, resulted in an improvement in sleep parameters, but weight control alone was not uniformly effective.

Blood Pressure↗

PubMed2006

Alleviation of sleep apnea in patients with chronic renal failure by nocturnal cycler-assisted peritoneal dialysis compared with conventional continuous ambulatory peritoneal dialysis.

Nocturnal hemodialysis has been shown to improve sleep apnea in patients who receive conventional hemodialysis. It was hypothesized that nocturnal peritoneal dialysis (NPD) also is effective in correcting sleep apnea in patients who receive continuous ambulatory PD (CAPD). Overnight polysomnography (PSG) was performed in 46 stable NPD and CAPD patients who were matched for demographic and clinical attributes. The prevalence of sleep apnea, defined as an apnea-hypopnea index (AHI; or frequency of apnea and hypopnea per hour of sleep) > or =15, was 52% for NPD patients and 91% for CAPD patients (P = 0.007). The mean (+/-SD) AHI in NPD and CAPD patients was 31.6 +/- 25.6 and 50.9 +/- 26.4 (P = 0.025), respectively. For validation of the efficacy of NPD in alleviating sleep apnea, a fixed sequence intervention study was performed in which 24 incident PD patients underwent one PSG study during mandatory cycler-assisted NPD while awaiting their turn for CAPD training and a second PSG recording shortly after they were established on stable CAPD. The prevalence of sleep apnea was 4.2% during NPD and 33.3% during CAPD (P = 0.016). AHI increased from 3.4 +/- 1.34 during NPD to 14.0 +/- 3.46 during CAPD (P < 0.001). With the use of bioelectrical impedance analysis, total body water content was significantly lower during stable NPD than CAPD (32.8 +/- 7.37 versus 35.1 +/- 7.35 L; P = 0.004). NPD delivered greater reductions in total body water (-2.81 +/- 0.45 versus -1.34 +/- 0.3 L; P = 0.015) and hydration fraction (-3.63 +/- 0.64 versus -0.71 +/- 0.52%; P = 0.005) during sleep. Pulmonary function tests remained unchanged before and after conversion from NPD to CAPD. These findings suggest that NPD may have a therapeutic edge over CAPD in sleep apnea that is associated with renal failure as a result of better fluid clearance during sleep.

Adult↗

PubMed2006

Advanced glycation endproducts in nondiabetic patients with obstructive sleep apnea.

SUBJECT OBJECTIVE: The formation and accumulation of advanced glycation endproducts (AGEs) has been implicated in the progression of age-related diseases such as diabetes mellitus and atherosclerosis. We hypothesize that AGE concentrations may be increased in subjects with obstructive sleep apnea (OSA), a condition associated with increased oxidative stress. METHODS: One hundred nineteen nondiabetic patients with OSA and 234 age-matched healthy controls and 134 patients with type 2 diabetes were recruited for participation in the study. Serum AGEs were assayed by competitive enzyme-linked immunosorbent assay using a polyclonal rabbit antisera raised against AGE-RNase. RESULTS: Serum AGEs were increased in OSA subjects, as compared with controls, but were less increased than the AGEs of patients with type 2 diabetes (control: 3.22 +/- 0.54 unit per mL; OSA: 3.68 +/- 0.39; diabetes mellitus: 4.11 +/- 0.99; analysis of variance p < .01). In the subjects with OSA, serum AGEs correlated with the duration of nocturnal desaturation (r = 0.21, p = .025) and plasma total 8-isoprostane concentration, a biochemical marker of oxidative stress (r = 0.22, p = .015), but not with fasting glucose level. On general linear model univariate analysis, the association between serum AGEs and 8-isoprostane was independent of age, sex, body mass index, smoking status, and glucose. CONCLUSION: Serum levels of AGEs were increased in nondiabetic subjects with OSA and were associated with the severity of OSA. Whether increased AGE formation contributes significantly to the high cardiovascular risk associated with OSA remains to be determined.

Diabetes Mellitus, Type 2↗

PubMed2005

Obstructive sleep apnea and the metabolic syndrome in community-based Chinese adults in Hong Kong.

OBJECTIVE: To investigate the relationship between obstructive sleep apnea (OSA) and the metabolic syndrome, an established cardiovascular risk factor, in middle-aged Chinese subjects. DESIGN: A prospective cross-sectional study from community-dwelling volunteers. SUBJECTS: Subjects of either sex between 30 and 60 years old were recruited from the staff in public institutions or visitors to community centers in Hong Kong. METHODS: Demographic and anthropomentric indices, blood pressure and metabolic profile (fasting blood glucose, total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol and triglycerides) were measured. Overnight polysomnographic studies were conducted. Presence of obstructive sleep apnea (OSA) was defined as apnea-hypopnea index (AHI)5. Metabolic syndrome was defined by the criteria of the National Cholesterol Education Panel, but using Asian cut-off values for abdominal obesity. RESULTS: A total of 255 subjects (150 men, 105 women) were studied. Subjects with OSA had five-fold risk of having metabolic syndrome. OSA was associated with the metabolic syndrome or its components, including waist circumference, diastolic blood pressure and fasting glucose, after adjusting for confounding variables. The independent determinants of OSA were age, gender, body mass index (BMI) and the metabolic syndrome. CONCLUSION: Among community-based middle-aged Chinese subjects, the metabolic syndrome was independent predictor of OSA.

Adult↗

PubMed2005

Analysis of TGF-beta(1) gene polymorphisms in Hong Kong Chinese patients with asthma.

BACKGROUND: The C-509T polymorphism of TGF-beta(1) gene has been associated with asthma and atopy in white populations. OBJECTIVE: We investigated the association between asthma and previously identified polymorphisms at C-509T and T869C of the TGF-beta(1) gene among 250 Chinese patients with asthma and 308 healthy controls in Hong Kong. METHODS: Genotyping was performed on peripheral blood genomic DNA by using PCR-RFLP. RESULTS: There were no differences in the frequencies of genotypes and alleles between patients and controls. The C-509T and T869C polymorphisms were in tight linkage disequilibrium (P < .01). Among atopic subjects, significant differences were found in genotype and allele frequencies for T869C polymorphism between patients and controls (P = .014 and P = .019, respectively), and individuals bearing the CC genotype were associated with increased risk for the development of asthma (odds ratio, 2.58; 95% CI, 1.17-5.66; P = .018) after adjusting for age, sex, and smoking status. Individuals with asthma bearing the CT genotype of the C-509T polymorphism had significantly increased risk for severe airflow obstruction compared with individuals who had mild obstruction (odds ratio, 4.00; 95% CI, 1.06-15.08; P = .035). CONCLUSION: Our results indicate that the polymorphisms at C-509T and T869C of the TGF-beta(1) gene are associated with asthma susceptibility in atopic subjects of the Hong Kong Chinese population, and the C-509T polymorphism may play a role in the pathogenesis of airflow obstruction.

Adult↗

PubMed2005

HDL dysfunction in obstructive sleep apnea.

OBJECTIVE: HDL is anti-atherogenic and has antioxidant property. HDL dysfunction has been reported in patients with coronary heart disease and we hypothesize that HDL may also be dysfunctional in obstructive sleep apnea (OSA), a condition associated with increased oxidative stress. METHODS: 128 OSA patients and 82 controls were recruited. HDL dysfunction was determined by evaluating the ability of HDL to inhibit LDL oxidation ex vivo. Plasma HDL was incubated with native LDL in the presence of dichlorofluorescein which fluoresced upon interaction with lipid oxidation products. Plasma levels of oxidized LDL and 8-isoprostane were measured by ELISA and a specific enzyme immunoassay, respectively. RESULTS: Plasma total 8-isoprostane levels were elevated in OSA subjects (p<0.01). Despite having similar concentrations of plasma lipids and apolipoproteins as controls, OSA subjects had greater degree of HDL dysfunction (p<0.01) and increased oxidized LDL levels (p<0.05). The apnea-hypopnea index was the main determinant of HDL dysfunction in OSA, accounting for 30% of its variance, with oxidized LDL and apolipoprotein AI contributing to 8% and 5% of its variance respectively (p<0.001). CONCLUSION: HDL is dysfunctional in preventing the formation and inactivation of oxidized lipids in OSA subjects and may partly contribute to their increased cardiovascular risk.

Adult↗

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

Antioxidant enzyme activities in healthy Chinese adults: influence of age, gender and smoking.

OBJECTIVE: Specific antioxidant enzymes play a vital role in regulating and maintaining oxidant species. The aim of this study was to determine these antioxidant enzyme activities (i.e. catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx)) in erythrocytes from a group of healthy Chinese subjects and to study the influence of age, gender and smoking habits on the enzyme activities. METHODOLOGY: Chinese healthy subjects (n = 276) were grouped according to their age range, gender differences and smoking habits. Antioxidant enzyme activities were measured spectrophotometrically using standard kinetic methods. RESULTS: There was a significant decrease in erythrocyte GPx activity in ever-smokers compared with non-smokers (47.10 +/- 1.33 mU/g haemoglobin (Hb) vs. 51.41 +/- 1.64 mU/g Hb, P < 0.05). Age-related significant increases in erythrocyte CAT and SOD activities were found in non-smokers but not in ever-smokers. There was no age-related difference in erythrocyte GPx activity in either non-smokers or ever-smokers. Among those >60 years old, erythrocyte CAT and GPx activities were significantly lower in ever-smokers than in non-smokers (29.70 +/- 3.07 mU/g Hb vs. 41.63 +/- 4.92 mU/g Hb (P < 0.05), and 47.55 +/- 2.00 mU/g Hb vs. 55.30 +/- 3.60 mU/g Hb (P < 0.05), respectively). It was also found that females had higher erythrocyte GPx activity than males but this difference did not reach significance in non-smokers. CONCLUSION: From the results of this study, it is concluded that oxidative stress seems to be present in elderly ever-smokers among the Chinese population.

Adolescent↗

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

A Chinese version of the Sleep Apnea Quality of Life Index was evaluated for reliability, validity, and responsiveness.

OBJECTIVE: Obstructive sleep apnea (OSA) is a common disorder in many ethnic populations. Patients with OSA have impaired health-related quality of life (HRQOL). No sleep apnea-specific HRQOL measure has been validated in Chinese patients. STUDY DESIGN AND SETTING: A cross-sectional sample of 106 Chinese OSA patients and a longitudinal sample of 51 patients in Hong Kong completed a Chinese (Cantonese) version of SAQLI for assessment of its acceptability, scaling assumptions, reliability, validity, and responsiveness. RESULTS: The instrument was understood and seen as relevant by 97% of subjects. Internal consistency, test-retest reliability, item-scale convergent validity and discriminatory validity, and construct validity were good to excellent. Construct validity was confirmed by significant correlations with SF-36 subscale scores. However, factor analysis showed that only items of daily functioning and symptom domains all loaded on the hypothesized scales. Longitudinal data showed that SAQLI was more responsive than SF-36 to changes after treatment. CONCLUSION: Hence, this version of SAQLI was an acceptable, psychometrically valid, and responsive HRQOL measure for evaluating impact of illness and treatment effectiveness in Chinese OSA patients.

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

A community study of sleep-disordered breathing in middle-aged Chinese women in Hong Kong: prevalence and gender differences.

STUDY OBJECTIVES: To investigate the prevalence of sleep-disordered breathing (SDB) and obstructive sleep apnea syndrome (OSAS) in community-based, middle-aged Chinese women, and to compare the differences between gender with a similar study in men. DESIGN: A cross-sectional study conducted in Hong Kong from 1998 to 2000. SETTING: Sleep questionnaires were distributed to women (30 to 60 years old) in three offices and two community centers. All were invited to undergo full polysomnography in a sleep laboratory. PARTICIPANTS: Questionnaires were distributed to 1,532 women, and 854 questionnaires were returned. Polysomnography was conducted in 106 respondents. MEASUREMENTS AND RESULTS: Conservative estimated prevalence of SDB (apnea-hypopnea index [AHI] > = 5) and OSAS (AHI > or = 5 plus excessive daytime sleepiness [EDS]) were 3.7% and 2.1%, respectively. Age-specific prevalence of OSAS was 0.5%, 2.2%, and 6.1% in the 30- to 39-year-old, 40- to 49-year-old, and 50- to 60-year-old age groups, respectively. Stepwise multiple logistic regression analysis identified body mass index (BMI) and age as predictors of SDB. Compared to Chinese men, the prevalence of SDB and OSAS in women was lower, but the gender difference decreased with age. The AHI of affected women was also significantly lower despite comparable BMI. Compared to men, women with SDB had same degree of self-reported snoring and a similar degree of EDS despite the lower AHI. CONCLUSIONS: This study demonstrated an estimated prevalence of OSAS at 2.1% among middle-aged Chinese women in Hong Kong, with a 12-fold rise from the fourth to the sixth decade of life. BMI and age were significant independent predictors of SDB. Compared to men, women with SDB had lower AHIs, despite similar BMIs.

Adult↗

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

Sputum sol neutrophil elastase activity in bronchiectasis: differential modulation by syndecan-1.

The persistently dominant activity of neutrophil elastase in bronchial secretions replete with antielastases is crucial to the pathogenesis of bronchiectasis. We hypothesize that components in the bronchial secretions bind neutrophil elastase and compromise the inhibitory efficiency of prevailing antielastases. Zymographic analysis of sputum sols from patients with bronchiectasis found elastase activity in a polydisperse, alcian blue-stained zone of high molecular mass. This suggested that neutrophil elastase was complexed with polyanionic partners. Western blot analysis found not only the polyanionic partner, heparan sulfate/syndecan-1, but also the physiological antielastases, secretory leukoproteinase inhibitor and alpha1-antitrypsin, in the complex. Both dissociative density gradient ultracentrifugation and heparin displacement revealed that elastase dissociated from heparan sulfate/syndecan-1 was fully inhibited by the endogenous antielastases. This contrasts with the effects of exogenous antielastases on sputum neutrophil elastase activity-that of alpha1-antitrypsin was limited, but that of secretory leukoproteinase inhibitor was facilitated. Similarly, complexed elastase on blots of sputum sol zymographs was bound and inhibited by exogenous secretory leukoproteinase inhibitor but not by exogenous alpha1-antitrypsin. Taken together, the results bring a new focus to heparan sulfate/syndecan-1 complexed with neutrophil elastase in inflamed bronchial secretions as a target for modulating elastase susceptibility to physiological antielastases.

Blotting, Western↗

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↗

PubMed2002

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.

Adult↗