Risk factors, clinical features and prognosis of perioperative stroke in adults

INTRODUCTION: Perioperative stroke (POS) is an uncommon but severe surgical complication. No widely accepted guidelines for risk prediction or management have been established. Its prevention depends on knowledge about the nature of this disease. METHODS: A total of 36 cases and equal number of controls in Hong Kong West Cluster hospitals were recruited over 43 months. Peri- and intra-operative features were compared and characteristics of POS were described. RESULTS: Atrial fibrillation, diabetes mellitus (DM), and history of stroke were identified as risk factors (P=0.017, 0.002, and 0.003, respectively). Prolonged aortic occlusion (P=0.018) and bypass (P=0.002) contributed in cardiac surgery. Only few BP parameters, but not consistently all, were significant; 78% POS were infarcts. Watershed infarction related to hypotension was uncommon. Beta-blocker use seemed to bare protective effect. Blood loss and haemoglobin levels did not correlate to POS. Three-month mortality rate was 36%. CONCLUSION: Optimal DM control and cardioversion before elective OT, perioperative anticoagulation in AF and old stroke patients, and beta-blockers may be preventive measures for POS. Role of hypotension in POS aetiology is debatable.published_or_final_versionThe 15th Medical Research Conference; Department of Medicine, The University of Hong Kong, Hong Kong, 16 January 2010. In Hong Kong Medical Journal, 2010, v. 16 suppl. 1, p. 13, abstract no.

Public healthcare financing and provision in Hong Kong : a public-private partnership approach

published_or_final_versionPolitics and Public AdministrationMasterMaster of Public Administratio

Phylogenetic relationships among the genera of the Penaeidae (Crustacea : Decapoda) revealed by mitochondrial 16S rRNA gene sequences

The phylogenetic relationships within the family Penaeidae are examined based on mitochondrial 16S rRNA gene sequence analysis of 30 species from 20 genera. The analysis generally supports the three- tribe scheme proposed by Burkenroad ( 1983) but it is not consistent with the five- group classification of Kubo ( 1949). Three clades are resolved: ( Penaeus sensu stricto + Fenneropenaeus + Litopenaeus + Farfantepenaeus + Marsupenaeus + Melicertus + Funchalia + Heteropenaeus), ( Metapenaeus + Parapenaeopsis + Xiphopenaeus + Rimapenaeus + Megokris + Trachysalambria) and ( Metapenaeopsis + Penaeopsis + Parapenaeus), corresponding to the Penaeini, Trachypenaeini and Parapenaeini respectively, while the affinities of Atypopenaeus and Trachypenaeopsis are obscure. The molecular data support that Miyadiella represents the juvenile stage of Atypopenaeus. Within the Trachypenaeini, Trachypenaeus sensu lato is clearly paraphyletic, while the monophyly of Penaeus sensu lato in the Penaeini is questionable.The phylogenetic relationships within the family Penaeidae are examined based on mitochondrial 16S rRNA gene sequence analysis of 30 species from 20 genera. The analysis generally supports the three- tribe scheme proposed by Burkenroad ( 1983) but it is not consistent with the five- group classification of Kubo ( 1949). Three clades are resolved: ( Penaeus sensu stricto + Fenneropenaeus + Litopenaeus + Farfantepenaeus + Marsupenaeus + Melicertus + Funchalia + Heteropenaeus), ( Metapenaeus + Parapenaeopsis + Xiphopenaeus + Rimapenaeus + Megokris + Trachysalambria) and ( Metapenaeopsis + Penaeopsis + Parapenaeus), corresponding to the Penaeini, Trachypenaeini and Parapenaeini respectively, while the affinities of Atypopenaeus and Trachypenaeopsis are obscure. The molecular data support that Miyadiella represents the juvenile stage of Atypopenaeus. Within the Trachypenaeini, Trachypenaeus sensu lato is clearly paraphyletic, while the monophyly of Penaeus sensu lato in the Penaeini is questionable

Genome maps across 26 human populations reveal population-specific patterns of structural variation.

Large structural variants (SVs) in the human genome are difficult to detect and study by conventional sequencing technologies. With long-range genome analysis platforms, such as optical mapping, one can identify large SVs (>2 kb) across the genome in one experiment. Analyzing optical genome maps of 154 individuals from the 26 populations sequenced in the 1000 Genomes Project, we find that phylogenetic population patterns of large SVs are similar to those of single nucleotide variations in 86% of the human genome, while ~2% of the genome has high structural complexity. We are able to characterize SVs in many intractable regions of the genome, including segmental duplications and subtelomeric, pericentromeric, and acrocentric areas. In addition, we discover ~60 Mb of non-redundant genome content missing in the reference genome sequence assembly. Our results highlight the need for a comprehensive set of alternate haplotypes from different populations to represent SV patterns in the genome

Oral health of community dwelling elders in Hong Kong

Introduction: The world’s population is ageing and the elders are vulnerable to oral health problems. This project aimed to observe the oral health status of community dwelling elders in Hong Kong, investigate the oral health impact on their quality of life and nutritional status, and provide oral health education and preventive service. Methods: Community dwelling elders (65 or above) were recruited from five community centers. An interviewer-administered questionnaire was completed to collect information on their socio-demographic background and oral health perception/practice. Their oral health related quality of life (OHQoL) and nutritional status were measured by using the Geriatric Oral Health Assessment Index (GOHAI) and Mini-Nutritional Assessment (MNA), respectively. Their tooth and periodontal status, oral hygiene and soft tissues were examined. Individualized advice, oral health education and scaling were provided. Results: A total of 195 elders participated. Despite their sound knowledge on dental caries, their awareness of the causes and risk factors of periodontal diseases was low. Several misconceptions of oral health were common and their expectation towards oral health was low. Although 81% brush their teeth at least twice a day, over 75% did not perform interdental cleaning mainly due to unawareness of the necessity (32%) and lack of skills (42%). Their dental visits were treatment-driven and mainly for pain-relieving and emergency care. Only 19% were regular dental attendees. The mean (SD) DMFT was 8.9 (7.8). Over 60% had periodontal pockets; 6% were edentulous and 38% had fewer than 20 teeth. The mean (SD) total GOHAI score was 56.4 (8.0); 60% reported negative impact of oral health on their quality of life. The mean (SD) MNA score was 25.2 (2.9); 30% had malnutrition or were at risk. Multivariate analysis showed that tooth loss and untreated decayed teeth (DT) were significant determinants of poor OHQoL; older age, higher education level, and poorer OHQoL were significantly associated with higher risk of malnutrition (all p<0.05). Conclusions: Oral health problems are common among community dwelling elders in Hong Kong. Their oral health awareness and practice are yet to be improved. Tooth loss and unmet treatment need for dental caries significantly compromise elders’ quality of life, which in turn increases their risk for malnutrition. Outreach oral health education and service are well received by the community.published_or_final_versio

Glucose transport in the bovine ciliary body epithelium (CBE)

Diabetic patients are prone to develop cataract, compared to non-diabetic patients (Kyselova et al., 2004). The global prevalence of diabetes is around 150 millions in 2004 (5% of the world population), with 1.8 million people in the United Kingdom affected (Diabetes UK, 2004). In western countries, diabetes accounts for around 12% of the total cataract population (Harding, 1999). It has been proposed that hyperglycemia is the major risk factor in diabetic cataract, and could be the starting point for all of the consequent pathological changes including, glucoxidation, glycation and activation of the polyol pathway, which finally result in diabetic complications (Sensi et al., 1995 Hotta, 1997 Brownlee, 2001). The present study aimed to characterise the mechanism of glucose transport into the aqueous humour. Using the Ussing-type chamber technique, glucose transport kinetics were characterised for the bovine CBE. The glucose fluxes were sensitive to a number of glucose transporter inhibitors including cytochalasin B ( 80% inhibition), phloretin ( 59% inhibition) and phlorizin ( 21% inhibition), and it also varied with stromal glucose concentration. In an investigation of mRNA expression using RT-PCR, GLUT1, GLUT3, GLUT4, GLUT5 and SGLT2 were found to be expressed in the bovine CBE. Due to difficulties encountered in the protein expression study, it was not possible to confirm that all of these mRNAs are translated. Nevertheless, the major glucose transport mechanism across the bovine CBE was determined to be a facilitative and carrier-mediated mode, since the glucose transport was effectively inhibited by the addition of cytochalasin B and phloretin. The transport system is likely to saturate when the plasma glucose concentration reaches 10.6 mM. These results, together with the gene expression data, may provide a new insight into devising a therapeutic strategy in the control of aqueous glucose levels which may eventually prevent the diabetic cataract formation

Delayed clearance of viral load and marked cytokine activation in severe cases of pandemic H1N1 2009 influenza virus infection

Background: Infections caused by the pandemic H1N1 2009 influenza virus range from mild upper respiratory tract syndromes to fatal diseases. However, studies comparing virological and immunological profile of different clinical severity are lacking. Methods: We conducted a retrospective cohort study of 74 patients with pandemic H1N1 infection, including 23 patients who either developed acute respiratory distress syndrome (ARDS) or died (ARDS-death group), 14 patients with desaturation requiring oxygen supplementation and who survived without ARDS (survived-withoutARDS group), and 37 patients with mild disease without desaturation (mild-disease group). We compared their pattern of clinical disease, viral load, and immunological profile. Results: Patients with severe disease were older, more likely to be obese or having underlying diseases, and had lower respiratory tract symptoms, especially dyspnea at presentation. The ARDS-death group had a slower decline in nasopharyngeal viral loads, had higher plasma levels of proinflammatory cytokines and chemokines, and were more likely to have bacterial coinfections (30.4%), myocarditis (21.7%), or viremia (13.0%) than patients in the survived-without-ARDS or the mild-disease groups. Reactive hemophagocytosis, thrombotic phenomena, lymphoid atrophy, diffuse alveolar damage, and multiorgan dysfunction similar to fatal avian influenza A H5N1 infection were found at postmortem examinations. Conclusions: The slower control of viral load and immunodysregulation in severe cases mandate the search for more effective antiviral and immunomodulatory regimens to stop the excessive cytokine activation resulting in ARDS and death. © 2010 by the Infectious Diseases Society of America. All rights reserved.published_or_final_versio

Application of Linear Discriminant Analysis in Dimensionality Reduction for Hand Motion Classification

The classification of upper-limb movements based on surface electromyography (EMG) signals is an important issue in the control of assistive devices and rehabilitation systems. Increasing the number of EMG channels and features in order to increase the number of control commands can yield a high dimensional feature vector. To cope with the accuracy and computation problems associated with high dimensionality, it is commonplace to apply a processing step that transforms the data to a space of significantly lower dimensions with only a limited loss of useful information. Linear discriminant analysis (LDA) has been successfully applied as an EMG feature projection method. Recently, a number of extended LDA-based algorithms have been proposed, which are more competitive in terms of both classification accuracy and computational costs/times with classical LDA. This paper presents the findings of a comparative study of classical LDA and five extended LDA methods. From a quantitative comparison based on seven multi-feature sets, three extended LDA-based algorithms, consisting of uncorrelated LDA, orthogonal LDA and orthogonal fuzzy neighborhood discriminant analysis, produce better class separability when compared with a baseline system (without feature projection), principle component analysis (PCA), and classical LDA. Based on a 7-dimension time domain and time-scale feature vectors, these methods achieved respectively 95.2% and 93.2% classification accuracy by using a linear discriminant classifier