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Zhai L, Xiao H, Lin C, Wong HLX, Lam YY, Gong M, Wu G, Ning Z, Huang C, Zhang Y, Yang C, Luo J, Zhang L, Zhao L, Zhang C, Lau JYN, Lu A, Lau LT, Jia W, Zhao L, Bian ZX. Gut microbiota-derived tryptamine and phenethylamine impair insulin sensitivity in metabolic syndrome and irritable bowel syndrome. Nat Commun 2023; 14:4986. [PMID: 37591886 PMCID: PMC10435514 DOI: 10.1038/s41467-023-40552-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 07/31/2023] [Indexed: 08/19/2023] Open
Abstract
The incidence of metabolic syndrome is significantly higher in patients with irritable bowel syndrome (IBS), but the mechanisms involved remain unclear. Gut microbiota is causatively linked with the development of both metabolic dysfunctions and gastrointestinal disorders, thus gut dysbiosis in IBS may contribute to the development of metabolic syndrome. Here, we show that human gut bacterium Ruminococcus gnavus-derived tryptamine and phenethylamine play a pathogenic role in gut dysbiosis-induced insulin resistance in type 2 diabetes (T2D) and IBS. We show levels of R. gnavus, tryptamine, and phenethylamine are positively associated with insulin resistance in T2D patients and IBS patients. Monoassociation of R. gnavus impairs insulin sensitivity and glucose control in germ-free mice. Mechanistically, treatment of R. gnavus-derived metabolites tryptamine and phenethylamine directly impair insulin signaling in major metabolic tissues of healthy mice and monkeys and this effect is mediated by the trace amine-associated receptor 1 (TAAR1)-extracellular signal-regulated kinase (ERK) signaling axis. Our findings suggest a causal role for tryptamine/phenethylamine-producers in the development of insulin resistance, provide molecular mechanisms for the increased prevalence of metabolic syndrome in IBS, and highlight the TAAR1 signaling axis as a potential therapeutic target for the management of metabolic syndrome induced by gut dysbiosis.
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Affiliation(s)
- Lixiang Zhai
- Centre for Chinese Herbal Medicine Drug Development, Hong Kong Baptist University, Hong Kong SAR, China
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong SAR, China
| | - Haitao Xiao
- School of Pharmaceutical Sciences, Health Science Center, Shenzhen University, Shenzhen, China
| | - Chengyuan Lin
- Centre for Chinese Herbal Medicine Drug Development, Hong Kong Baptist University, Hong Kong SAR, China
| | | | - Yan Y Lam
- Centre for Chinese Herbal Medicine Drug Development, Hong Kong Baptist University, Hong Kong SAR, China
| | - Mengxue Gong
- State Key Laboratory of Microbial Metabolism and Ministry of Education Key Laboratory of Systems Biomedicine, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Guojun Wu
- Department of Biochemistry and Microbiology and New Jersey Institute for Food, Nutrition, and Healthy. School of Environmental and Biological Sciences, Rutgers University, New Brunswick, NJ, 08901, USA
| | - Ziwan Ning
- Centre for Chinese Herbal Medicine Drug Development, Hong Kong Baptist University, Hong Kong SAR, China
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong SAR, China
| | - Chunhua Huang
- Centre for Chinese Herbal Medicine Drug Development, Hong Kong Baptist University, Hong Kong SAR, China
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong SAR, China
| | - Yijing Zhang
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong SAR, China
| | - Chao Yang
- Department of Computer Science, Hong Kong Baptist University, Hong Kong SAR, China
| | - Jingyuan Luo
- Centre for Chinese Herbal Medicine Drug Development, Hong Kong Baptist University, Hong Kong SAR, China
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong SAR, China
| | - Lu Zhang
- Department of Computer Science, Hong Kong Baptist University, Hong Kong SAR, China
| | - Ling Zhao
- Academy of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Chenhong Zhang
- State Key Laboratory of Microbial Metabolism and Ministry of Education Key Laboratory of Systems Biomedicine, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Johnson Yiu-Nam Lau
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong SAR, China
| | - Aiping Lu
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong SAR, China
| | - Lok-Ting Lau
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong SAR, China
| | - Wei Jia
- Phenome Research Centre, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong SAR, China.
- Shanghai Key Laboratory of Diabetes Mellitus and Center for Translational Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China.
| | - Liping Zhao
- Department of Biochemistry and Microbiology and New Jersey Institute for Food, Nutrition, and Healthy. School of Environmental and Biological Sciences, Rutgers University, New Brunswick, NJ, 08901, USA.
| | - Zhao-Xiang Bian
- Centre for Chinese Herbal Medicine Drug Development, Hong Kong Baptist University, Hong Kong SAR, China.
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong SAR, China.
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Tsang PYL, Chu SLH, Li LCW, Tai DMS, Cheung BKC, Kebede FT, Leung PYM, Wong W, Chung T, Yip CCY, Poon RWS, Chen JHK, Yuen KY, Fok M, Lau JYN, Lau LT. Automated System for Multiplexing Detection of COVID-19 and Other Respiratory Pathogens. IEEE J Transl Eng Health Med 2022; 11:424-434. [PMID: 37435542 PMCID: PMC10332469 DOI: 10.1109/jtehm.2022.3230716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 11/16/2022] [Accepted: 12/16/2022] [Indexed: 09/30/2023]
Abstract
OBJECTIVE Infectious diseases are global health challenge, impacted the communities worldwide particularly in the midst of COVID-19 pandemic. The need of rapid and accurate automated systems for detecting pathogens of concern has always been critical. Ideally, such systems shall detect a large panel of pathogens simultaneously regardless of well-equipped facilities and highly trained operators, thus realizing on-site diagnosis for frontline healthcare providers and in critical locations such as borders and airports. METHODS & RESULTS Avalon Automated Multiplex System, AAMST, is developed to automate a series of biochemistry protocols to detect nucleic acid sequences from multiple pathogens in one test. Automated processes include isolation of nucleic acids from unprocessed samples, reverse transcription and two rounds of amplifications. All procedures are carried out in a microfluidic cartridge performed by a desktop analyzer. The system was validated with reference controls and showed good agreement with their laboratory counterparts. In total 63 clinical samples, 13 positives including those from COVID-19 patients and 50 negative cases were detected, consistent with clinical diagnosis using conventional laboratory methods. CONCLUSIONS The proposed system has demonstrated promising utility. It would benefit the screening and diagnosis of COVID-19 and other infectious diseases in a simple, rapid and accurate fashion. Clinical and Translational Impact Statement- A rapid and multiplex diagnostic system proposed in this work can clinically help to control spread of COVID-19 and other infectious agents as it can provide timely diagnosis, isolation and treatment to patients. Using the system at remoted clinical sites can facilitate early clinical management and surveillance.
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Affiliation(s)
- Parker Y. L. Tsang
- Emerging Viral Diagnostics (HK) Ltd.Hong KongChina
- Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityHong KongChina
| | - Sunny L. H. Chu
- Emerging Viral Diagnostics (HK) Ltd.Hong KongChina
- Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityHong KongChina
| | | | | | | | - Firaol Tamiru Kebede
- Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityHong KongChina
| | - Pete Y. M. Leung
- Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityHong KongChina
| | - Winston Wong
- Emerging Viral Diagnostics (HK) Ltd.Hong KongChina
| | - Teresa Chung
- Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityHong KongChina
| | - Cyril C. Y. Yip
- Department of MicrobiologyThe University of Hong KongHong KongChina
| | | | | | - Kwok-Yung Yuen
- Department of MicrobiologyThe University of Hong KongHong KongChina
- Centre for VirologyVaccinology and Therapeutics, Hong Kong Science and Technology ParkHong KongChina
| | - Manson Fok
- Emerging Viral Diagnostics (HK) Ltd.Hong KongChina
- Faculty of MedicineMacau University of Science and TechnologyMacauChina
| | - Johnson Y. N. Lau
- Emerging Viral Diagnostics (HK) Ltd.Hong KongChina
- Department of BiologyHong Kong Baptist UniversityHong KongChina
| | - Lok-Ting Lau
- Emerging Viral Diagnostics (HK) Ltd.Hong KongChina
- Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityHong KongChina
- School of Chinese MedicineHong Kong Baptist UniversityHong KongChina
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3
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Chung T, Tam IYS, Lam NYY, Yang Y, Liu B, He B, Li W, Xu J, Yang Z, Zhang L, Cao JN, Lau LT. Non-targeted detection of food adulteration using an ensemble machine-learning model. Sci Rep 2022; 12:20956. [PMID: 36470940 PMCID: PMC9722920 DOI: 10.1038/s41598-022-25452-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022] Open
Abstract
Recurrent incidents of economically motivated adulteration have long-lasting and devastating effects on public health, economy, and society. With the current food authentication methods being target-oriented, the lack of an effective methodology to detect unencountered adulterants can lead to the next melamine-like outbreak. In this study, an ensemble machine-learning model that can help detect unprecedented adulteration without looking for specific substances, that is, in a non-targeted approach, is proposed. Using raw milk as an example, the proposed model achieved an accuracy and F1 score of 0.9924 and 0. 0.9913, respectively, when the same type of adulterants was presented in the training data. Cross-validation with spiked contaminants not routinely tested in the food industry and blinded from the training data provided an F1 score of 0.8657. This is the first study that demonstrates the feasibility of non-targeted detection with no a priori knowledge of the presence of certain adulterants using data from standard industrial testing as input. By uncovering discriminative profiling patterns, the ensemble machine-learning model can monitor and flag suspicious samples; this technique can potentially be extended to other food commodities and thus become an important contributor to public food safety.
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Affiliation(s)
- Teresa Chung
- grid.16890.360000 0004 1764 6123Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong China
| | - Issan Yee San Tam
- grid.16890.360000 0004 1764 6123Research and Innovation Office, The Hong Kong Polytechnic University, Hung Hom, Hong Kong China
| | - Nelly Yan Yan Lam
- grid.221309.b0000 0004 1764 5980Institute for Innovation, Translation and Policy Research, Hong Kong Baptist University, Kowloon Tong, Hong Kong China ,Food Safety Consortium, Hong Kong, China
| | - Yanni Yang
- grid.16890.360000 0004 1764 6123Department of Computing, The Hong Kong Polytechnic University, Hung Hom, Hong Kong China
| | - Boyang Liu
- Inner Mongolia Mengniu Dairy (Group) Co., Ltd, Hohhot, China
| | - Billy He
- grid.16890.360000 0004 1764 6123Department of Computing, The Hong Kong Polytechnic University, Hung Hom, Hong Kong China
| | - Wengen Li
- grid.16890.360000 0004 1764 6123Department of Computing, The Hong Kong Polytechnic University, Hung Hom, Hong Kong China
| | - Jie Xu
- Danone Open Science Research Center, Shanghai, China
| | - Zhigang Yang
- Inner Mongolia Mengniu Dairy (Group) Co., Ltd, Hohhot, China
| | - Lei Zhang
- grid.16890.360000 0004 1764 6123Department of Computing, The Hong Kong Polytechnic University, Hung Hom, Hong Kong China
| | - Jian Nong Cao
- grid.16890.360000 0004 1764 6123Department of Computing, The Hong Kong Polytechnic University, Hung Hom, Hong Kong China
| | - Lok-Ting Lau
- grid.16890.360000 0004 1764 6123Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong China ,grid.221309.b0000 0004 1764 5980Institute for Innovation, Translation and Policy Research, Hong Kong Baptist University, Kowloon Tong, Hong Kong China ,Food Safety Consortium, Hong Kong, China ,grid.221309.b0000 0004 1764 5980School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong China
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Yu F, Lau LT, Fok M, Lau JYN, Zhang K. COVID-19 Delta variants—Current status and implications as of August 2021. Precision Clinical Medicine 2021; 4:287-292. [PMID: 35692860 PMCID: PMC8499995 DOI: 10.1093/pcmedi/pbab024] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 09/07/2021] [Accepted: 09/07/2021] [Indexed: 01/03/2023] Open
Abstract
The SARS-CoV-2 Delta variant has evolved as the dominant strain of the current pandemic. Studies have shown that this variant has increased infectivity/viral load, and reduced neutralization by the host antibodies from convalescent patients/vaccinees. Clinically, Delta variant infection has been observed/documented in convalescent patients/vaccinees, although with less incidence of severe diseases, but can serve as reservoir to spread the infection to the unvaccinated. The current understanding (as of 18 August 2021) on the virologic aspect (including the amino acid substitutions), clinical implications, and public health implications will be discussed in this mini review, and recommendations to health authorities will be provided.
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Affiliation(s)
- Flora Yu
- Department of Natural Sciences and Mathematics, University of Texas at Dallas, Richardson, Texas 75080-3021, USA
| | - Lok-Ting Lau
- Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR 999077, China
| | - Manson Fok
- University Hospital and Faculty of Medicine, Macau University of Science and Technology, Macau SAR 999078, China
| | | | - Kang Zhang
- University Hospital and Faculty of Medicine, Macau University of Science and Technology, Macau SAR 999078, China
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5
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Yee A, Tsui NBY, Kwan RYC, Leung AYM, Lai CKY, Chung T, Lau JYN, Fok M, Dai DLK, Lau LT. Apolipoprotein E Gene Revisited: Contribution of Rare Variants to Alzheimer's Disease Susceptibility in Southern Chinese. Curr Alzheimer Res 2021; 18:67-79. [PMID: 33761857 DOI: 10.2174/1567205018666210324111401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 12/28/2020] [Accepted: 02/16/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND APOE ε4 is the best-known risk factor for late-onset alzheimer's disease (AD). Population studies have demonstrated a relatively low prevalence of APOE ε4 among Chinese population, implying additional risk factors that are Chinese-specific may exist. Apart from - alleles, genetic variation profile along the full-length APOE has rarely been investigated. OBJECTIVE In this study, we filled this gap by comprehensively determining all genetic variations in APOE and investigated their potential associations with late-onset AD and mild cognitive impairment (MCI) in southern Chinese. METHODS Two hundred and fifty-seven southern Chinese participants were recruited, of whom 69 were AD patients, 83 had MCI, and 105 were normal controls. Full-length APOE from promoter to 3'UTR regions were sequenced. Genetic variants were identified and compared among the three groups. RESULTS While APOE ε4 was more significantly found in AD patients, the prevalence of APOE ε4 in southern Chinese AD patients was the lowest when compared to other areas of China and nearby regions, as well as other countries worldwide. We further identified 13 rare non-singleton variants in APOE. Significantly more AD patients carried any of the rare non-singleton variants than MCI and normal subjects. Such difference was observed in the non-carriers of ε4-allele only. Among the identified rare variants, the potential functional impact was predicted for rs532314089, rs553874843, rs533904656 and rs370594287. CONCLUSION Our study suggests an ethnic difference in genetic risk composition of AD in southern Chinese. Rare variants on APOE are a potential candidate for AD risk stratification biomarker in addition to APOE-ε4.
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Affiliation(s)
- Anita Yee
- Avalon Genomics (Hong Kong) Limited, Shatin,Hong Kong
| | | | - Rick Y C Kwan
- Centre for Gerontological Nursing, School of Nursing, The Hong Kong Polytechnic University, Hung Hom,Hong Kong
| | - Angela Y M Leung
- Centre for Gerontological Nursing, School of Nursing, The Hong Kong Polytechnic University, Hung Hom,Hong Kong
| | - Claudia K Y Lai
- Centre for Gerontological Nursing, School of Nursing, The Hong Kong Polytechnic University, Hung Hom,Hong Kong
| | - Teresa Chung
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom,Hong Kong
| | | | - Manson Fok
- Faculty of Health Sciences, Macau University of Science and Technology, Taipa, Macau,Hong Kong
| | - David L K Dai
- Hong Kong Alzheimer's Disease Association, Wang Tau Hom,Hong Kong
| | - Lok-Ting Lau
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom,Hong Kong
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Yee A, Tsui NB, Chang YN, Au CS, Fok M, Lau LT, Chung T, Chung G, Kwan RY, Leung AY, Lau JY, Dai DL. Alzheimer's disease: insights for risk evaluation and prevention in the Chinese population and the need for a comprehensive programme in Hong Kong/China. Hong Kong Med J 2019; 24:492-500. [PMID: 30232267 DOI: 10.12809/hkmj187244] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
With the ageing of the global population, China is projected to be impacted significantly by the rising number of patients with Alzheimer's disease (AD). A cure for AD is not yet available, so society should be prepared for an increasing AD-related burden. In this review, we examine this impending problem and provide overviews on (a) the magnitude of the problem of AD in Hong Kong/China in the near future; (b) the genetic and lifestyle risk factors that contribute to AD; (c) current diagnostic approaches and the potential of newly discovered genetic biomarkers for early detection; (d) medications, non-pharmacological interventions, and possible preventive measures; and (e) the need for social and psychological care from the community. In Hong Kong, primary care and AD-related support for at-risk individuals, patients, and caregivers are inadequate. A joint effort from the medical community, government, universities, non-governmental organisations/charities, and industry should initiate the development of a long-term programme for AD. Finally, we outline recommendations for the relevant parties to consider.
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Affiliation(s)
- A Yee
- Avalon Genomics (HK) Limited, Shatin, Hong Kong
| | - N By Tsui
- Avalon Genomics (HK) Limited, Shatin, Hong Kong.,Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hunghom, Hong Kong
| | - Y N Chang
- Avalon Genomics (HK) Limited, Shatin, Hong Kong
| | - C Sm Au
- Yan Oi Tong Clarea Au Eldergarten, Kwun Tong, Hong Kong
| | - M Fok
- Avalon Genomics (HK) Limited, Shatin, Hong Kong.,Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hunghom, Hong Kong.,Faculty of Health Sciences, Macau University of Science and Technology, Macau
| | - L T Lau
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hunghom, Hong Kong
| | - T Chung
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hunghom, Hong Kong
| | - G Chung
- Faculty of Health Sciences, Macau University of Science and Technology, Macau
| | - R Yc Kwan
- Centre for Gerontological Nursing, School of Nursing, The Hong Kong Polytechnic University, Hunghom, Hong Kong
| | - A Ym Leung
- Centre for Gerontological Nursing, School of Nursing, The Hong Kong Polytechnic University, Hunghom, Hong Kong
| | - J Yn Lau
- Avalon Genomics (HK) Limited, Shatin, Hong Kong.,Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hunghom, Hong Kong
| | - D Lk Dai
- Hong Kong Alzheimer's Disease Association, Hong Kong
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Kwan RYC, Leung AYM, Yee A, Lau LT, Xu XY, Dai DLK. Cognitive Frailty and Its Association with Nutrition and Depression in Community-Dwelling Older People. J Nutr Health Aging 2019; 23:943-948. [PMID: 31781723 DOI: 10.1007/s12603-019-1258-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND Cognitive frailty is a condition where physical frailty and mild cognitive impairment (MCI) co-exist. It is associated with increased risk of dementia and dependency. Previous studies reported that malnutrition and depression are associated with physical frailty and MCI; however, their relationships with cognitive frailty remained to be explored. The aims of this study were to examine the association of nutrition and depression with cognitive frailty, in comparison to having physical frailty or MCI alone. METHODS This study employed a cross-sectional design. Data collection was conducted in the community settings on the older people without dementia. Dependent variables were cognitive frailty, physical frailty, and MCI. The independent variables were depression and nutrition. Multi-nominal regression was employed to examine the relationships between the dependent and independent variables. The associations were adjusted by four known co-variates, including age, gender, education and APOE ε4 carrier status. RESULTS A total of 185 participants were recruited from four community centres and one elderly hostel and completed the data collection. Approximately 44.9% of the older people with physical frailty and 82.5% of elderly with MCI belonged to cognitive frailty. Multi-nominal regression models showed that depression is positively associated with cognitive frailty and with physical frailty, but not associated with solely MCI. Nutrition is negatively associated with cognitive frailty, but not associated with physical frailty or MCI alone. CONCLUSION Cognitive frailty is associated with malnutrition and depression. Therapeutic interventions managing depression and malnutrition may focus the older people with cognitive frailty to improve efficacy and cost-effectiveness.
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Affiliation(s)
- R Y C Kwan
- David L.K. Dai, Hong Kong Alzheimer's Disease Association, G/F, Wang Yip House, Wang Tau Hom Estate, Hong Kong Tel: (852) 2338 1120 Fax: (852) 23380772
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8
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Yu ACH, Vatcher G, Yue X, Dong Y, Li MH, Tam PHK, Tsang PYL, Wong AKY, Hui MHK, Yang B, Tang H, Lau LT. Nucleic acid-based diagnostics for infectious diseases in public health affairs. Front Med 2012; 6:173-86. [PMID: 22660977 PMCID: PMC7088663 DOI: 10.1007/s11684-012-0195-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Accepted: 03/03/2012] [Indexed: 11/29/2022]
Abstract
Infectious diseases, mostly caused by bacteria and viruses but also a result of fungal and parasitic infection, have been one of the most important public health concerns throughout human history. The first step in combating these pathogens is to get a timely and accurate diagnosis at an affordable cost. Many kinds of diagnostics have been developed, such as pathogen culture, biochemical tests and serological tests, to help detect and fight against the causative agents of diseases. However, these diagnostic tests are generally unsatisfactory because they are not particularly sensitive and specific and are unable to deliver speedy results. Nucleic acid-based diagnostics, detecting pathogens through the identification of their genomic sequences, have shown promise to overcome the above limitations and become more widely adopted in clinical tests. Here we review some of the most popular nucleic acid-based diagnostics and focus on their adaptability and applicability to routine clinical usage. We also compare and contrast the characteristics of different types of nucleic acid-based diagnostics.
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Affiliation(s)
- Albert Cheung-Hoi Yu
- Neuroscience Research Institute, Department of Neurobiology, School of Basic Medical Sciences, Key Laboratory for Neuroscience, Peking University, Beijing, 100191, China.
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9
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Wei Z, Nie YH, Lau LT, Lu J, Yu ACH. [Progress in functional polyphosphate in prokaryotic and eukaryotic living organisms]. Sheng Li Ke Xue Jin Zhan 2009; 40:197-202. [PMID: 19803421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Polyphosphate (poly P) has been widely identified in both inorganic environment and living organisms. Research shows that poly P in bacteria enhances their resistance to severe environment, triggers their protective responses, increases biofilm formation and involves in predation and bacterial virulence. In eukaryotes, poly P has been found to enhance the proliferation of fibroblast and many tumor cell lines, induce the calcification of osteoblast and be involved in calcium ion release. Based on the existing information, we attempt to discuss the possible functions of poly P in the nervous system.
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Affiliation(s)
- Zheng Wei
- Neuroscience Research Institute, Peking University, Beijing, China
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10
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Cao B, Li R, Liu YM, Cao ZX, Geng XQ, Lau LT, Lu J, Wu L, Cui SF, Bai RT, Yu CH, Wang C. [The impact of antibiotic treatment in patients with influenza-like illness]. Zhonghua Jie He He Hu Xi Za Zhi 2008; 31:483-487. [PMID: 19035224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
OBJECTIVE To study the etiology of influenza-like illness (ILI) in Beijing, and to investigate the impact of antibiotic treatment on outcomes. METHODS This was a prospective cohort study. Patients with diagnosis of influenza-like illness were prospectively enrolled for study of bacterial and viral pathogens. Demographic characteristics, underlying diseases, respiratory and extrapulmonary symptoms, laboratory tests were also collected for analysis of relationship between drug therapy and outcomes. RESULTS A total of 476 cases were enrolled between Dec. 2006 and Apr. 2007, of whom 454 cases were used for analysis. Influenza virus was the most common pathogen( n = 197, 43.4%), with other pathogens rarely seen. The mean age of the patients was (33 +/- 13) years, and the ratio of male to female was 1.1:1. Twenty four patients (5.3% ) received influenza vaccine. The rate of antibiotic prescription after onset of illness was 63.4%, but none received antiviral drugs such as Oseltamivir and amantadine. Compared with influenza-negative patients, patients with influenza were older, had more underlying diseases and had greater severity of symptoms such as cough, sore throat, headache and myalgia (but with no statistical differences). The influenza syndrome (T > or = 39 degrees C plus cough, sore throat and headache or myalgia) was more common in the influenza group compared to the influenza-negative patients (P < 0.05). The ratio of antibiotic prescription was 67% in the influenza group, and the total white blood cell and platelet count, percentage of neutrophils were higher in antibiotic treatment patients compared with non-antibiotic treatment patients (P < 0.01). The cost in patients who received antibiotics was twice as much as non-antibiotic treatment patients (P < 0.05), but the defervescence time and respiratory symptom alleviation time did not differ. Cox regression analysis showed that the total white blood count and the differentials (OR value 1.049 and 1.014, respectively), but not antibiotic use were the independent risk factors for longer defervescence time. CONCLUSION Influenza virus was the most common pathogen for adult patients with ILI in Beijing city during the winter and the spring seasons. Antibiotic treatment of adult patients with ILI did not improve illness resolution, while the cost was increased significantly.
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Affiliation(s)
- Bin Cao
- Department of Infectious Diseases and Clinical Microbiology, Beijing Chaoyang Hospital, Beijing Institute of Respiratory Medicine, Capital Medical University, Beijing 100020, China
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Lau LT, Reid SM, King DP, Lau AMF, Shaw AE, Ferris NP, Yu ACH. Detection of foot-and-mouth disease virus by nucleic acid sequence-based amplification (NASBA). Vet Microbiol 2007; 126:101-10. [PMID: 17728080 DOI: 10.1016/j.vetmic.2007.07.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2006] [Revised: 07/09/2007] [Accepted: 07/10/2007] [Indexed: 11/28/2022]
Abstract
A study was conducted to evaluate the performance of a nucleic acid sequence-based amplification (NASBA) assay for the detection of foot-and-mouth disease virus (FMDV). Two detection methods: NASBA-electrochemiluminescence (NASBA-ECL) and a newly developed NASBA-enzyme-linked oligonucleotide capture (NASBA-EOC) were evaluated. The diagnostic sensitivity of these assays was compared with other laboratory-based methods using 200 clinical samples collected from different regions of the world. Assay specificity was also assessed using samples (n=43) of other viruses that cause vesicular disease in livestock and genetic relatives of FMDV. Concordant results were generated for 174/200 (87.0%) of suspect FMD samples between NASBA-ECL and real-time RT-PCR. In comparison with the virus isolation (VI) data, the sensitivity of the NASBA-ECL assay was 92.9%, which was almost identical to that of the real-time RT-PCR (92.4%) for the same set of samples. There was broad agreement between the results of the NASBA-ECL and the simpler NASBA-EOC detection method for 97.1% of samples. In conclusion, this study provides further data to support the use of NASBA as a rapid and sensitive diagnostic method for the detection and surveillance of FMDV.
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Affiliation(s)
- Lok-Ting Lau
- Hai Kang Life Corporation Limited, 8/F Hang Tung Resources Centre, 18 A-Kung Ngam Village Road, Shau Kei Wan, Hong Kong SAR, China
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Lau LT, Fung YWW, Yu ACH. Detection of animal viruses using nucleic acid sequence-based amplification (NASBA). Dev Biol (Basel) 2006; 126:7-15; discussion 323. [PMID: 17058476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
As seen in recent avian influenza outbreaks in Asia, prevention is the key to fighting infectious disease successfully. Efficient disease surveillance systems on the basis of molecular diagnostics will help monitor the emergence of viruses in the early stage and thus prompt containment measures can be in place to minimize disease spread. Here we describe and review molecular diagnostics focusing on nucleic acid sequence-based amplification (NASBA) technology in detecting viruses causing animal diseases, such as avian influenza, foot-and-mouth disease, and Newcastle disease. NASBA offers high sensitivity, specificity, accuracy, and speed of availability of results, and NASBA would be the most applicable molecular diagnostics for disease surveillance and control.
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Affiliation(s)
- L T Lau
- Hong Kong DNA Chips Ltd, Hang Tung Resources Centre, Shau Kei Wan, China
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Feng Q, Yu H, Liu Y, He C, Hu J, Sang H, Ding N, Ding M, Fung YWW, Lau LT, Yu ACH, Chen J. Genome comparison of a novel foot-and-mouth disease virus with other FMDV strains. Biochem Biophys Res Commun 2004; 323:254-63. [PMID: 15351730 DOI: 10.1016/j.bbrc.2004.08.086] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2004] [Indexed: 11/18/2022]
Abstract
The genome of a novel foot-and-mouth disease virus, HKN/2002, was 8104 nucleotides (nt) in length (excluding the poly(C) tract and poly(A) tail) and was composed of a 1042-nt 5'-untranslated region (UTR), a 6966-nt open reading frame, and a 93-nt 3'-UTR. Genome sequences of HKN/2002 and other known FMDV strains were compared. The VP1, VP2, and VP3-based neighbor-joining (NJ) trees were divided into distinct clusters according to different serotypes, while other region-based NJ trees exhibited some degree of intercross among serotypes. Mutations in HKN/2002 were revealed, including frequent deletions and insertions in the G-H loop of VP1, and deletion involving 10 amino acid residues in the 3A protein. An evolutionary relationship of HKN/2002 with an Asian FMDV lineage isolated from a Hong Kong swine host in 1970 was postulated. A 43-nt deletion identified in the 5'-UTR of HKN/2002 possibly contributed to the loss of one pseudo-knot domain.
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Affiliation(s)
- Qian Feng
- Department of Cell Biology and Genetics, College of Life Sciences, Peking University, Beijing 100871, China
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Affiliation(s)
- Yin-Wan Wendy Fung
- Ministry of Education (PKU) and Department of Neurobiology, Neuroscience Research Institute, Peking University, Key Laboratory of Neuroscience, Peking University Health Science Centre, Beijing, China and Hong Kong DNA Chips Limited, 1/F Cosmos Center, 108 Soy Street, Mongkok, Kowloon, Hong Kong, SAR China
| | - Lok-Ting Lau
- Ministry of Education (PKU) and Department of Neurobiology, Neuroscience Research Institute, Peking University, Key Laboratory of Neuroscience, Peking University Health Science Centre, Beijing, China and Hong Kong DNA Chips Limited, 1/F Cosmos Center, 108 Soy Street, Mongkok, Kowloon, Hong Kong, SAR China
| | - Albert Cheung-Hoi Yu
- Ministry of Education (PKU) and Department of Neurobiology, Neuroscience Research Institute, Peking University, Key Laboratory of Neuroscience, Peking University Health Science Centre, Beijing, China and Hong Kong DNA Chips Limited, 1/F Cosmos Center, 108 Soy Street, Mongkok, Kowloon, Hong Kong, SAR China
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Lau LT, Banks J, Aherne R, Brown IH, Dillon N, Collins RA, Chan KY, Fung YWW, Xing J, Yu AC. Nucleic acid sequence-based amplification methods to detect avian influenza virus. Biochem Biophys Res Commun 2004; 313:336-42. [PMID: 14684165 PMCID: PMC7111163 DOI: 10.1016/j.bbrc.2003.11.131] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Infection of poultry with highly pathogenic avian influenza virus (AIV) can be devastating in terms of flock morbidity and mortality, economic loss, and social disruption. The causative agent is confined to certain isolates of influenza A virus subtypes H5 and H7. Due to the potential of direct transfer of avian influenza to humans, continued research into rapid diagnostic tests for influenza is therefore necessary. A nucleic acid sequence-based amplification (NASBA) method was developed to detect a portion of the haemagglutinin gene of avian influenza A virus subtypes H5 and H7 irrespective of lineage. A further NASBA assay, based on the matrix gene, was able to detect examples of all known subtypes (H1–H15) of avian influenza virus. The entire nucleic acid isolation, amplification, and detection procedure was completed within 6 h. The dynamic range of the three AIV assays was five to seven orders of magnitude. The assays were sensitive and highly specific, with no cross-reactivity to phylogenetically or clinically relevant viruses. The results of the three AIV NASBA assays correlated with those obtained by viral culture in embryonated fowl’s eggs.
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Affiliation(s)
- Lok-Ting Lau
- Department of Neuroscience, Peking University Health Science Center, Key Laboratory of Neuroscience (Peking University), Neuroscience Research Institute, Peking University, Ministry of Education, 38 Xue Yuan Road, Beijing 100083, China
- Hong Kong DNA Chips Ltd, 1/F, Cosmos Centre, 108 Soy Street, Kowloon, Hong Kong SAR, China
| | - Jill Banks
- Veterinary Laboratories Agency, New Haw, Addlestone, Woking, Surrey KT15 3NB, UK
| | - Rebecca Aherne
- Veterinary Laboratories Agency, New Haw, Addlestone, Woking, Surrey KT15 3NB, UK
| | - Ian H. Brown
- Veterinary Laboratories Agency, New Haw, Addlestone, Woking, Surrey KT15 3NB, UK
| | - Natalie Dillon
- Hong Kong DNA Chips Ltd, 1/F, Cosmos Centre, 108 Soy Street, Kowloon, Hong Kong SAR, China
| | - Richard A. Collins
- Hong Kong DNA Chips Ltd, 1/F, Cosmos Centre, 108 Soy Street, Kowloon, Hong Kong SAR, China
| | - Ka-Yun Chan
- Hong Kong DNA Chips Ltd, 1/F, Cosmos Centre, 108 Soy Street, Kowloon, Hong Kong SAR, China
| | - Yin-Wan Wendy Fung
- Department of Neuroscience, Peking University Health Science Center, Key Laboratory of Neuroscience (Peking University), Neuroscience Research Institute, Peking University, Ministry of Education, 38 Xue Yuan Road, Beijing 100083, China
- Hong Kong DNA Chips Ltd, 1/F, Cosmos Centre, 108 Soy Street, Kowloon, Hong Kong SAR, China
| | - Jun Xing
- Hong Kong DNA Chips Ltd, 1/F, Cosmos Centre, 108 Soy Street, Kowloon, Hong Kong SAR, China
| | - Albert C.H. Yu
- Department of Neuroscience, Peking University Health Science Center, Key Laboratory of Neuroscience (Peking University), Neuroscience Research Institute, Peking University, Ministry of Education, 38 Xue Yuan Road, Beijing 100083, China
- Hong Kong DNA Chips Ltd, 1/F, Cosmos Centre, 108 Soy Street, Kowloon, Hong Kong SAR, China
- Corresponding author. Fax: +852-2111-9762
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Abstract
Nucleic acid sequence-based amplification (NASBA) allows the rapid amplification of specific regions of nucleic acid obtained from a diverse range of sources. It is especially suitable for amplifying RNA sequences. A NASBA technique was developed that allows the detection of avian influenza A subtype H5 from allantoic fluid harvested from inoculated chick embryos. The amplified viral RNA is detected by electrochemiluminescence. The described NASBA technique is a specific, rapid, and sensitive method of detection of influenza A subtype H5 viruses. More importantly, it can be used to distinguish high- and low-pathogenicity strains of the H5 subtype.
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Affiliation(s)
- R A Collins
- Hong Kong DNA Chips Ltd., 1805-6, 18F, Lu Plaza, 2 Wing Yip Street, Kowloon, Hong Kong SAR, China
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Chen X, Feng Q, Wu Z, Liu Y, Huang K, Shi R, Chen S, Lu W, Ding M, Collins RA, Fung YWW, Lau LT, Yu ACH, Chen J. RNA-dependent RNA polymerase gene sequence from foot-and-mouth disease virus in Hong Kong. Biochem Biophys Res Commun 2003; 308:899-905. [PMID: 12927804 DOI: 10.1016/s0006-291x(03)01511-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A foot-and-mouth disease virus (FMDV, HKN/2002) was isolated in Hong Kong in 2002. The nucleotide sequence of the 3D(pol) gene encoding the viral RNA-dependent RNA polymerase was determined and compared with that of the same gene from other FMDVs. The 3D(pol) gene was 1410 nucleotides in length encoding a protein of 470 amino acid residues. Sequence comparisons indicated that HKN/2002 belonged to serotype O. An evolutionary tree based on the 3D(pol) sequences of 20 FMDV isolates revealed that the nucleotide sequence of the HKN/2002 3D(pol) gene was most similar to those of isolates found in Taiwan in 1997, suggesting that they share a common ancestor. The amino acid sequence of the HKN/2002 3D(pol) gene was determined and aligned with those of representative isolates from seven other Picornaviridae genera. Eight highly conserved regions were detected, indicating a conserved functional relevance for these motifs. Alignment of 20 FMDV 3D(pol) amino acid sequences revealed a hypermutation region near the N-terminus that may help the virus evade host immune systems.
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Affiliation(s)
- Xi Chen
- Department of Cell Biology and Genetics, College of Life Sciences, Peking University, Beijing 100871, PR China
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Collins RA, Wu WS, Xing J, Lau LT, Yu ACH. Parentage testing anomalies in Hong Kong SAR of China. Chin Med J (Engl) 2003; 116:708-11. [PMID: 12875686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023] Open
Abstract
OBJECTIVE To determine if there are any differences in the number of exclusions from paternity of men using an anonymous parentage testing service compared with that of men using an in-person parentage testing service provided by the same company in Hong Kong SAR of China. METHODS Comparable numbers of consecutive anonymous and in-person parentage tests conducted by the same company were analyzed. RESULTS Men using an anonymous parentage testing service were excluded from paternity at a significantly greater rate (P < 0.001), compared with men using an in-person parentage test service. CONCLUSIONS The results obtained from anonymous parentage testing indicate that the number of families containing children of doubtful parentage is much greater than expected previously. As illegitimate children are known to suffer greater degrees of abuse and neglect, this finding poses serious social questions regarding the welfare of families, which the relevant authorities should acknowledge and address.
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Affiliation(s)
- Richard A Collins
- Hong Kong DNA Chips Limited, 1805-6, 18/F Lu Plaza, 2 Wing Yip Street, Kowloon, Hong Kong SAR, China
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Feng Q, Chen X, Ma O, Liu Y, Ding M, Collins RA, Ko LS, Xing J, Lau LT, Yu ACH, Chen J. Serotype and VP1 gene sequence of a foot-and-mouth disease virus from Hong Kong (2002). Biochem Biophys Res Commun 2003; 302:715-21. [PMID: 12646228 DOI: 10.1016/s0006-291x(03)00250-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The nucleotide sequence of the VP1 coding region of foot-and-mouth disease virus (FMDV) strain HKN/2002, isolated from a disease outbreak occurring in Hong Kong in February 2002, was determined and compared with the sequences of other FMDVs. The VP1 coding region was 639 nucleotides in length and encoded a protein of 213 amino acid residues. Comparison of the VP1 nucleotide sequence with those of other isolates indicated that HKN/2002 belonged to serotype O. A VP1-based sequence similarity tree of several South-east Asian FMDV-O isolates showed that HKN/2002 was most closely related to FMDV isolates found in Hong Kong from 1991 to 1999 and Taiwan in 1997. Comparison of the amino acid sequence of the major immunogenic region of HKN/2002 with that of the serotype O vaccine strain, O1/Manisa/Turkey/69, reveals significant similarity, indicating that current serotype O vaccines may offer some degree of protection against HKN/2002.
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Affiliation(s)
- Qian Feng
- Department of Cell Biology and Genetics, College of Life Sciences, Peking University, Beijing 100871, China
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Shan S, Ko LS, Collins RA, Wu Z, Chen J, Chan KY, Xing J, Lau LT, Yu ACH. Comparison of nucleic acid-based detection of avian influenza H5N1 with virus isolation. Biochem Biophys Res Commun 2003; 302:377-83. [PMID: 12604358 DOI: 10.1016/s0006-291x(03)00165-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Nucleic acid sequence-based amplification with electrochemiluminescent detection (NASBA/ECL) of avian influenza virus was compared with viral culture in embryonated chicken eggs. Virus was isolated from blood or anal swabs of chickens artificially infected with highly pathogenic avian influenza A/Chicken/Hong Kong/1000/97 (H5N1). Viral nucleic acid was detected in blood samples by NASBA/ECL immediately prior to death, whilst nucleic acid extracted from anal swabs was detected from the day following artificial infection until death. Thus, blood and/or anal swabs are a suitable source of material for the detection of avian influenza in dead birds, but anal swabs are more suitable for detection of viral genetic material in live birds. Dilution of a known viral standard was used to determine the limit of sensitivity for both NASBA/ECL and egg culture detection methods. The NASBA/ECL method was equivalent in sensitivity to egg culture. The NASBA/ECL results agreed with egg culture data in 71/94 (75.5%) tissue samples obtained from artificially infected birds.
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Affiliation(s)
- Songhua Shan
- Shanghai Entry-exit Inspection and Quarantine Bureau, China
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Collins RA, Ko LS, Fung KY, Chan KY, Xing J, Lau LT, Yu ACH. Rapid and sensitive detection of avian influenza virus subtype H7 using NASBA. Biochem Biophys Res Commun 2003; 300:507-15. [PMID: 12504113 DOI: 10.1016/s0006-291x(02)02896-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nucleic acid sequence-based amplification with electrochemiluminescent detection (NASBA/ECL) is an isothermal technique allowing rapid amplification and detection of specific regions of nucleic acid from a diverse range of sources. It is especially suitable for amplifying RNA. A NASBA/ECL technique has been developed allowing the detection of RNA from avian influenza virus subtype H7 derived from allantoic fluid harvested from inoculated chick embryos and from cell cultures. Degenerate amplification primers and amplicon capture probes were designed enabling the detection of low and highly pathogenic avian influenza of the H7 subtype from the Eurasian and North American lineages and the Australian sub-lineage. The NASBA/ECL technique is specific for subtype H7 and does not cross-react with other influenza subtypes or with viruses containing haemagglutinin-like genes. The assay is 10- to 100-fold more sensitive than a commercially available antigen capture immunoassay system. The NASBA/ECL assay could be used in high throughput poultry screening programmes.
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Affiliation(s)
- Richard A Collins
- Hong Kong DNA Chips Ltd., 1805-6, 18/F, Lu Plaza, 2 Wing Yip Street, Kowloon, Hong Kong SAR, China
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Abstract
Nucleic acid sequence-based amplification (NASBA) is an isothermal technique that allows the rapid amplification of specific regions of nucleic acid obtained from a diverse range of sources. It is especially suitable for amplifying RNA sequences. A rapid and specific NASBA technique was developed, allowing the detection of foot-and-mouth disease virus genetic material in a range of sample material, including preserved skin biopsy material from infected animals, vaccines prepared from denatured cell-free material, and cell-free antigen-based detection kits. A single pair of DNA oligonucleotide primers was able to amplify examples of all major FMD virus subtypes. The amplified viral RNA was detected by electrochemiluminescence. The method was at least as sensitive as existing cell-free antigen detection methods.
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Affiliation(s)
- Richard A Collins
- Hong Kong DNA Chips Ltd, 1805-6, 18/F, Lu Plaza, Kowloon, Hong Kong SAR, China
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Abstract
Astrocytes participate in a wide variety of important physiological processes and pathological insults, including ischemia. Information on the mechanism of astroglial injury and death during ischemic insult, however, is scarce. In this study, we investigated the mode of astrocytic cell death using an in vitro ischemic model. Cultured astrocytes exhibited several distinct morphological and biochemical features of apoptosis under ischemia. At 4 h of ischemia, Annexin V staining demonstrated an early commitment of some astrocytes to apoptosis. Condensed nuclei became visible from 4 h and the number increased with ischemic incubation time. Electron microscopy showed compacted and segregated chromatin along the edges of nuclear membranes. The number of TUNEL-positive nuclei and the degree of DNA laddering increased with ischemic incubation. Caspase-3, but not caspase-1, activity was increased in ischemia-injured astrocytes. Swollen mitochondria and vacuoles found in some cells with chromatin condensation indicated that these apoptotic-like cells might die of necrosis. The results imply that astrocytes are capable of undergoing apoptosis without the presence of other cell types, such as neurons. Ischemia can induce apoptosis in astrocytes contributing to the pathogenesis of ischemic injury in the CNS.
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Affiliation(s)
- A C Yu
- Neuroscience Research Institute, Peking University, Beijing, China.
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Lau LT, Yu AC. Astrocytes produce and release interleukin-1, interleukin-6, tumor necrosis factor alpha and interferon-gamma following traumatic and metabolic injury. J Neurotrauma 2001; 18:351-9. [PMID: 11284554 DOI: 10.1089/08977150151071035] [Citation(s) in RCA: 232] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The brain is no longer considered immune-privileged due to its capability of producing cytokines in response to neurotrauma; however, the cellular sources of cytokines have not been defined. This study focused on the production of four inflammatory cytokines, interleukin-1 (IL-1alpha), interleukin-6 (IL-6), tumor necrosis factor alpha (TNFalpha), and interferon gamma (IFN-gamma) in primary culture of astrocytes under two different injury models which simulated in vivo mechanical trauma (scratch injury) and ischemia. Results demonstrated that astrocytes after scratch injury were positively immunostained with IL-1alpha, IL-6, and TNFalpha. A slot-blot study of culture media showed that the release of IL-1alpha, IL-6, TNFalpha, and IFN-gamma by astrocytes subsequent to scratch and ischemic injury reached approximately twice the control values. The temporal expression of these cytokines was different for the two models. All four cytokines began to increase 1 h postscratch and remained at high levels throughout the experiment. In the ischemic model, however, the increase of cytokine expression was delayed until 4-8 h of ischemia, when sharp increases were seen in all four cytokines. In this culture system, the exogenous influence of blood-borne factors and leukocytes, which occur with in vivo trauma and ischemia, was eliminated. Accordingly, the cytokines detected in the culture media were derived from astrocytes. This study provides the first evidence that astrocytes, without the influence from other cell types, can produce and release cytokines following mechanical and ischemic injury.
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Affiliation(s)
- L T Lau
- Department of Biology, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, China
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Abstract
Astrocytes form an integral part of the blood brain barrier and are the first cell type in the central nervous system to encounter insult if there is an ischemic attack. The immunologic reaction of astrocytes to an ischemic insult would be affective to the subsequent responses of other nerve cells. We previously showed that ischemia caused an increase in the levels of interleukin 1alpha (IL-1alpha), tumor necrosis factor alpha (TNF alpha), and interleukin 6 (IL-6) in the culture medium of mouse cerebral cortical astrocyte. We did not have evidence on the source of these cytokines. This study aimed to investigate the expressions of these cytokine mRNAs in the astrocytes under ischemia. Results demonstrated that ischemia could induce necrosis and apoptosis in astrocytes. By using the RT-PCR method, we demonstrated for the first time that the mRNA levels of IL-1alpha, TNF alpha and IL-6 in normal astrocyte was very low, but their expressions could be induced quickly under ischemia. These cytokines might be interactive as indicated by the difference in time course of their expressions, with IL-1alpha being the earliest and IL-6 being the latest. The result provided some understanding of the induction and progression of these immunologic responses in astrocytes under ischemia. It also supported our previous findings that astrocytes contributed to the cytokines released under ischemia.
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Affiliation(s)
- A C Yu
- Department of Biology, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon.
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