PAK1 is involved in sensing the orientation of collagen stiffness gradients in mouse fibroblasts.

Migrating cells sense variations of stiffness in connective tissue matrices but how cells detect and respond to stiffness orientation is not defined. We examined cell extension formation on collagen with underlying support (vertical stiffness gradient) or on collagen laterally supported by nylon (lateral stiffness gradient). At 6 h after plating, cells plated on laterally-supported collagen exhibited >2-fold more abundant and ~2-fold longer cell extensions than cells plated on collagen with underlying support. We examined whether p21-activated kinase 1 (PAK1) influences extension formation that is dependent on the orientation of support. At 6 h after plating on collagen with underlying support, wild-type cell extensions were 40% shorter than PAK1 knockdown cells. In contrast, on laterally-supported collagen, wild-type cell extensions were 2-fold longer than PAK1 knockdown cells. In cells plated on laterally-supported collagen, there were ~2-fold reductions of collagen fiber alignment and compaction in PAK1 knockdown cells compared with wild-type cells. PAK1 knockdown did not affect collagen fiber alignment or compaction by cells plated on collagen with underlying support. Wild-type cells with lateral support of collagen exhibited 3-fold increases of phospho-myosin staining at 6h, which was 2-fold lower in PAK1 knockdown cells. In contrast, cells on collagen with underlying support showed no increase of phospho-myosin staining at any times. PAK1 knockdown did not affect α2 or ß1 integrin expression or function. We conclude that PAK1 is involved in the ability of cells to sense the orientation of stiffness in collagen substrates and generate contractile forces that affect cell extension formation.

Clinical significance of CDX2-positive circulating tumour cells in colorectal cancer patients.

BACKGROUND: Our recent work has shown the feasibility of using a refined immunomagnetic enrichment (IE) assay to detect cytokeratin 20-positive circulating tumour cells (CK20 pCTCs) in colorectal cancer (CRC) patients. We attempted to improve the sensitivity for CRC by detecting another intestinal-type differentiation marker, CDX2 pCTCs, using the same methodology. METHODS: CDX2 pCTCs were detected in patients with CRC, colorectal adenoma (CAD), benign colorectal diseases (BCD), other common cancers (OCC) and normal subjects (NS). Statistical analysis was used to correlate CDX2 pCTCs to the clinicohistopathological factors, recurrence, metastasis and survival after follow-up for 42 months in CRC patients. RESULTS: CDX2 pCTCs were detected in 81% CRC patients (73 out of 90, median number=21.5 CTCs), 7.5% CAD patients (3 out of 40), 0% patients with BCD (0 out of 90), 2.5% patients with OCC (2 out of 80) and 0% NS (0 out of 40). Furthermore, statistical analysis showed that CDX2 pCTC numbers were associated with tumour- node-metastasis stage and lymph node status. Using the median CDX2 pCTC numbers as the cutoff points, stratified groups of CRC patients had significant differences in their recurrence and survival. CONCLUSIONS: This study showed that the refined IE assay can detect CDX2 pCTCs with high sensitivity and that CDX2 pCTCs can generate clinically important information for CRC patients.

Early detection of central airway lung cancer in smokers with silicosis.

BACKGROUND: Smokers with silicosis are at increased risk of lung cancer. OBJECTIVE: To evaluate the feasibility of using autofluorescence bronchoscopy after sputum examination for early detection of large airway lung cancer and factors associated with the presence of cancerous and pre-cancerous lesions among smokers with silicosis. METHODS: Subjects at the pneumoconiosis clinic were recruited if they fulfilled the following criteria: 1) age ≥40 years, 2) smoking history of ≥20 pack-years and 3) confirmed diagnosis of silicosis. Sputum specimens were collected for cytology/cytometry examination and autofluorescence bronchoscopy was performed in subjects with an abnormal sputum result. RESULTS: A total of 48 subjects were recruited during the study period. The mean age and smoking history were respectively 63 ± 10 years and 51 ± 30 pack-years. Intraepithelial lung cancers and pre-neoplastic lesions (squamous metaplasia or above) were detected in respectively 2 (4.2%) and 14 (29.2%) subjects. The proportions of current smokers (75.0% vs. 40.6%, P = 0.03) and asbestos exposure (37.5% vs. 9.4%, P = 0.04) were significantly higher in subjects with the above lesions compared with those without. CONCLUSIONS: Sputum examination followed by autofluorescence bronchoscopy may be a useful way of identifying cancerous/pre-cancerous lesions among silicotic smokers. Current smoking and asbestos exposure were associated with these lesions.

Elevated plasma adiponectin levels in patients with chronic obstructive pulmonary disease.

BACKGROUND: Adiponectin is an anti-inflammatory adipokine that may play a role in chronic obstructive pulmonary disease (COPD) pathogenesis. OBJECTIVE: To investigate the relationship between adiponectin, interleukin (IL) 6, IL-8 and C-reactive protein (CRP) and COPD by evaluating these biomarkers in ever-smokers with or without the disease. METHOD: Plasma levels of adiponectin, IL-6, IL-8 and CRP were measured using commercially available kits in COPD patients (n = 71), healthy ever-smokers (n = 62) and non-smokers (n = 51). RESULTS: There were significant increases in plasma adiponectin, IL-6 and CRP in COPD patients (median [IQR] 4.39 microg/ml [2.68-6.98], 4.19 pg/ml [<2.40-6.40], 8.75 mg/l [4.26-40.63], respectively) compared to healthy ever-smokers (1.90 microg/ml [0.86-2.86], <2.40 pg/ml [<2.40-2.77], 3.71 mg/l [1.97-10.37 mg/l], respectively, P < 0.001) and non-smokers (1.76 microg/ml [1.34-2.52], <2.40 pg/ml [<2.40-2.78], 3.12 mg/l [2.11-5.71], respectively, P < 0.001). COPD patients had lower plasma IL-8 levels than healthy ever-smokers. Among ever-smokers with or without COPD, plasma adiponectin, IL-6 and CRP levels were inversely correlated with forced expiratory volume in 1 second (% predicted) after adjustment for age, body mass index, smoking status and pack-years. CONCLUSION: Our findings suggest that in COPD patients, adiponectin might be associated with COPD pathogenesis.

Dynamic formation of a hot field reversed configuration with improved confinement by supersonic merging of two colliding high-ß compact toroids.

A hot stable field-reversed configuration (FRC) has been produced in the C-2 experiment by colliding and merging two high-ß plasmoids preformed by the dynamic version of field-reversed θ-pinch technology. The merging process exhibits the highest poloidal flux amplification obtained in a magnetic confinement system (over tenfold increase). Most of the kinetic energy is converted into thermal energy with total temperature (T{i}+T{e}) exceeding 0.5 keV. The final FRC state exhibits a record FRC lifetime with flux confinement approaching classical values. These findings should have significant implications for fusion research and the physics of magnetic reconnection.

Relationship between glutathione S-transferase gene polymorphisms and enzyme activity in Hong Kong Chinese asthmatics.

BACKGROUND: Asthma is a disease associated with oxidative stress. The glutathione S-transferases (GST) are a group of enzymes that protect cells from oxidative stress. Functional genetic polymorphisms of GST genes (GSTT1, GSTM1 and GSTP1) have previously been reported. OBJECTIVE: To investigate the association of GST gene polymorphisms and its enzyme activity with the risk of asthma in Hong Kong Chinese adults. METHODS: An age- and smoking status-matched case-control study was carried out on 315 patients with asthma and 315 healthy controls. Genotyping was carried out on genomic DNA using the PCR and/or restriction fragment length polymorphism (PCR-RFLP). Plasma GST activity was measured by fluorometric assay. RESULTS: The distribution of various genotypes or alleles of the GSTT1, GSTM1 and GSTP1 was not significantly different between patients with asthma and healthy controls. The GSTM1 null genotype was found to be protective from the development of asthma in atopic subjects (odds ratios 0.55, 95% confidence interval 0.34-0.90; P=0.017). However, there was no association between GSTT1 and GSTM1 null genotypes and enzyme activity. GSTP1 codon 105 Val variants led to reduced plasma GST activity in healthy controls. Asthma patients had elevated plasma GST activity compared with healthy controls irrespective of their genotypes (P<0.001). CONCLUSION: Our data suggest that among atopic subjects, the GSTM1 null genotype is associated with a decreased risk for asthma despite increased level of plasma GST activity in asthma, but it could not distinguish whether this increase is a potentially protective compensatory effect or a pathogenic factor.

Polymorphisms of glutathione S-transferase genes and functional activity in smokers with or without COPD.

OBJECTIVE: To determine the role of polymorphisms of genes regulating glutathione S-transferase (GST) and its plasma GST activity in the pathogenesis of chronic obstructive pulmonary disease (COPD). DESIGN: Case-control study. METHODS: One hundred and sixty-three patients with stable COPD from several community or regional hospitals were matched for age and pack-years smoked with the same number of health controls from the general population. Each participant underwent an interview-based respiratory and smoking questionnaire, lung function testing and gave a blood sample. Genotyping was carried out using a polymerase chain reaction-based method for polymorphisms of glutathione S-transferase theta 1 (GSTT1), glutathione S-transferase mu 1 (GSTM1) and glutathione S-transferase P 1 (GSTP1) genes. Plasma GST activity was measured using the spectrofluorometric method. RESULTS: There were no significant differences in the distribution of various genotypes of polymorphisms of GSTT1, GSTM1 and GSTP1 between COPD patients and healthy controls. GST activity was significantly higher in patients compared with controls, irrespective of their different genotypes, and was not different between patients with different levels of airflow obstruction. CONCLUSION: Polymorphisms of GSTT1, GSTM1 and GSTP1 genes are unlikely to be involved in the pathogenesis of COPD in Chinese in Hong Kong and Southern China.

Determinants of chronic obstructive pulmonary disease in Chinese patients in Hong Kong.

BACKGROUND: The prevalence of chronic obstructive pulmonary disease (COPD) is rising in many parts of the world. This is a study of risk factors for COPD in Chinese patients in Hong Kong. DESIGN: Case-control study matched by sex and age (+/-5 years). METHODS: A total of 289 consecutive patients with COPD were recruited from out-patient clinics while healthy controls were recruited from two sources: random population and community centres for senior citizens. All patients and controls underwent a questionnaire-based interview and spirometry. RESULTS: The mean ages of COPD patients and controls were 71.1 +/- 9.4 and 67.5 +/- 9.3 years, respectively. The male to female ratio of COPD patients was 5 to 1. Smoking was found to be the most important determinant for COPD, followed by poor education and low body mass index adjusted for confounders. A dose-dependent relationship was found between the risk of COPD and pack-years smoked. Place of birth, exposure to environmental tobacco smoke and a history of asthma and tuberculosis were not associated with increased risk of COPD. CONCLUSION: Despite a progressive reduction in prevalence, smoking remains the most important predictor of COPD in Hong Kong. Greater anti-smoking efforts are warranted.

Prevalence and determinants of positive tuberculin reactions of residents in old age homes in Hong Kong.

OBJECTIVE: To determine the prevalence of tuberculous infection and the predictors of positive tuberculin reactivity in old age home residents in Hong Kong. DESIGN: Cross-sectional study. METHODS: A questionnaire-interview and review of medical records were carried out, together with measurement of weight and height/arm span and assessment of nutritional status. A one-stage tuberculin skin test (TST) was performed using two units of PPD RT23. An induration > or = 10 mm was considered as positive. RESULTS: Of 3682 residents (71.7% participation, mean age 82 years) who agreed to undergo a TST, 46.3% had a positive reaction. Factors associated with a significantly higher risk of a positive TST included being male, an ex- or current smoker and having a past history of tuberculosis (TB). Factors associated with reduced positive tuberculin reactivity included older age groups (> 70 years), a history of cancer and chronic obstructive pulmonary disease and low body mass index quartiles. CONCLUSION: In old age homes, the high prevalence of latent tuberculous infection is responsible for the high rate of active TB due to reactivation. Early diagnosis and treatment are necessary to prevent transmission of disease in these crowded environments with susceptible individuals.

Polymorphisms in manganese superoxide dismutase and catalase genes: functional study in Hong Kong Chinese asthma patients.

BACKGROUND: Reactive oxygen species may contribute to the pathogenesis of asthma. Functional genetic polymorphisms of antioxidant enzymes, superoxide dismutase (SOD) and catalase are good candidates for asthma susceptibility. OBJECTIVE: To investigate the association of the manganese-containing form of SOD (MnSOD) gene at amino acid position 16 (Val16Ala) and catalase gene in the promoter at A-21T and C-262T polymorphisms and asthma in a Hong Kong Chinese population. METHODS: The association study was conducted in a case-control design in asthma patients (n=251) and healthy controls (n=316) by genotyping. The functional significance was assessed by determining erythrocyte SOD and catalase activity. RESULTS: The Val allele of MnSOD at Val16Ala and the A allele of catalase gene at A-21T were not different between patients and controls, while the C allele of catalase gene at C-262T was found to be significantly different between patients and controls (P=0.033). The less frequent variant of catalase gene (-262T) was found to be protective from the development of asthma in a Hong Kong Chinese non-smoking population (adjusted odds ratio=0.35, 0.15-0.85; P=0.017). Asthma patients had elevated erythrocyte SOD and catalase activities in comparison with healthy controls (P<0.01). However, their activities were not associated with different genotypes within healthy controls or asthma patients. CONCLUSION: This is the first report showing that SOD and catalase functional activities are not associated with their respective genetic polymorphisms but related to the presence of asthma in a Hong Kong Chinese population.

Human endothelin converting enzyme-2 (ECE2): characterization of mRNA species and chromosomal localization.

Generation of the functionally pleiotropic members of the endothelin vasoactive peptide family is critically catalyzed by unique type II metalloproteases, termed endothelin converting enzymes (ECE). Isolation of human ECE-2 (EC 3.4.24.71) cDNAs revealed deduced open reading frames of 787 and 765 amino acids with approximately 60% identity with human ECE-1. Characterization of mRNA variants revealed mRNA structural diversity at the 5'-terminus. Two mRNA species exist containing distinct first and second exons. Furthermore, in one of these species, an in-frame deletion of the intracytoplasmic domain removed 29 amino acids. Because of the previously reported human genetic diseases ascribed to germline mutations of member genes of the endothelin family, ECE2 was localized in human chromosomes with fluorescence in situ hybridization and radiation hybrid mapping to 3q28-q29 and SHGC-20171/D3S1571, respectively.

Surgical infections in patients with chronic renal failure.

Patients with chronic renal failure and uremia have impaired host defenses and wound healing that can lead to an increased risk of infection in addition to a frequent need for surgical procedures with synthetic grafts and catheters. Antibiotic therapy plus timely surgical intervention in removal of infected grafts and catheters is crucial for infection control and patient survival. Other surgical infections, such as wound problems, intraabdominal infections, fungal infections, diabetic foot ulcers, and necrotizing soft tissue infections must be attended to promptly.

The first non-heart-beating organ donor in Hawaii--medical and ethical considerations.

The shortage of organ donors remains a major obstacle in transplantation in Hawaii. Some patients die while waiting for a life-saving organ. Across the nation, "marginal" donors, including non-heart-beating donors are used. The authors describe the first successful non-heart-beating organ donor transplant in Hawaii, and include medical and ethical considerations.

Diastolic blood pressure is related to urinary sodium excretion in hypertensive Chinese patients.

We studied 70 Hong Kong Chinese patients with untreated hypertension and 47 normotensive controls. Blood pressure measurements and 24-h urine collection were performed for each patient, and were repeated 12 weeks later in 14 hypertensive patients who remained untreated. Twenty-two hypertensive patients underwent ambulatory blood pressure monitoring. The primary hypothesis tested was a correlation between diastolic blood pressure and 24-h urinary sodium excretion. In the hypertensive patients, diastolic blood pressure correlated with 24-h urinary sodium excretion (r=0.41, p<0.001), even after adjustment for age, gender, body mass index, ethanol intake and season (r=0.34, p=0.02). In normotensive controls, diastolic blood pressure did not correlate with sodium excretion (r=0.21, p=0.16). A correlation between diastolic blood pressure and sodium excretion was also observed in the patients who underwent ambulatory blood pressure monitoring (r=0.47, p=0.026), and in repeat measurements in untreated patients (r=0.60, p=0.02). Systolic blood pressure did not correlate with sodium excretion, although it increased with patient age (0.6+/-0.1 mmHg/year, p<0.001). In a multiple regression analysis with diastolic blood pressure as the dependent variable, the regression coefficient was 0.06+/-0.02 mmHg/mmol Na. The regression coefficients for ambulatory diastolic blood pressure and diastolic pressure repeated at 12 weeks were 0.07+/-0.03 and 0. 09+/-0.04 mmHg/mmol Na, respectively. Urinary sodium excretion was related to diastolic blood pressure in our hypertensive patients, accounting for 17% of the variance of diastolic blood pressure.

Attitudes on organ donation among Hawaii physicians.

A survey of physicians attending the recent Hawaii Medical Association meeting was conducted in order to assess physician attitudes on organ donation. Physicians were asked 6 questions and demographics were collected. Results indicate that Hawaii physicians generally support organ donation and are aware of some of the current federal legislation regarding donation.

Organ donation and culture: a comparison of Asian American and European American beliefs, attitudes, and behaviors.

The well-known gap between organ-donor supply and demand in the United States is particularly acute for Asian Americans. Lower participation in organ donation programs by Asian Americans has been hypothesized as one explanation for this observation. This study finds that, relative to European Americans, Asian Americans hold more negative attitudes toward and participate less frequently in a large, urban organ-donor program. The study also hypothesizes and test possible reasons for subcultural differences in attitudes toward donation. Two cultural belief constructs hypothesized to more strongly predict Asian American attitudes and behaviors appear to impact both groups equally. Reasons for these results along with public policy implications and future research directions are discussed.

RNA diversity has profound effects on the translation of neuronal nitric oxide synthase.

A comprehensive analysis of the structure of neuronal nitric oxide synthase (nNOS; EC 1.14.13.39) mRNA species revealed NOS1 to be the most structurally diverse human gene described to date in terms of promoter usage. Nine unique exon 1 variants are variously used for transcript initiation in diverse tissues, and each is expressed from a unique 5'-flanking region. The dependence on unique genomic regions to control transcription initiation in a cell-specific fashion burdens the transcripts with complex 5'-mRNA leader sequences. Elaborate splicing patterns that involve alternatively spliced leader exons and exon skipping have been superimposed on this diversity. Highly structured nNOS mRNA 5'-untranslated regions, which have profound effects on translation both in vitro and in cells, contain cis RNA elements that modulate translational efficiency in response to changes in cellular phenotype.