1
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Cheung SKF, Choi LCW, Chan YS, Ho JCY, Lee CK, Kwok JSY. Identification of 58 novel HLA alleles identified in Chinese individuals by next-generation sequencing. HLA 2023. [PMID: 37376846 DOI: 10.1111/tan.15127] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 05/24/2023] [Accepted: 05/25/2023] [Indexed: 06/29/2023]
Abstract
HLA genes are the most polymorphic in the human genome. High resolution HLA typing from 13,870 bone marrow donors in Hong Kong was obtained using Next-generation sequencing (NGS) technology. Among the 67 novel alleles identified, official HLA allele names of 50 novel class I alleles (HLA-A, -B, -C) and 8 novel class II alleles (HLA-DRB1, -DQB1) were assigned by the World Health Organization (WHO) Nomenclature Committee for Factors of the HLA System.
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Affiliation(s)
- Stephen K F Cheung
- Division of Transplantation and Immunogenetics, Department of Pathology, Queen Mary Hospital, Hong Kong SAR, China
| | - Leo C W Choi
- Division of Transplantation and Immunogenetics, Department of Pathology, Queen Mary Hospital, Hong Kong SAR, China
| | - Y S Chan
- Division of Transplantation and Immunogenetics, Department of Pathology, Queen Mary Hospital, Hong Kong SAR, China
| | - Jenny C Y Ho
- Division of Transplantation and Immunogenetics, Department of Pathology, Queen Mary Hospital, Hong Kong SAR, China
| | - C K Lee
- Hong Kong Red Cross Blood Transfusion Services, Hong Kong SAR, China
| | - Janette S Y Kwok
- Division of Transplantation and Immunogenetics, Department of Pathology, Queen Mary Hospital, Hong Kong SAR, China
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2
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Cheung HN, Williams JM, Chan YS, Chan SWY. Measurement invariance of the Multidimensional Depression Assessment Scale (MDAS) across gender and ethnic groups of Asian, Caucasian, Black, and Hispanic. J Affect Disord 2022; 308:221-228. [PMID: 35429539 DOI: 10.1016/j.jad.2022.04.035] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 03/05/2022] [Accepted: 04/09/2022] [Indexed: 10/18/2022]
Abstract
BACKGROUND Major Depressive Disorder is a severe and highly disabling mental illness. Almost all self-reported questionnaires have overlooked the interpersonal symptoms of depression which are important across gender and culture. The Multidimensional Depression Assessment Scale (MDAS) developed by Cheung and Power (2012) entails comprehensive emotional, cognitive, somatic, and interpersonal subscales. It addresses the criticism that existing self-report depression scales might not cover sufficient phenomenological heterogeneity of depression. The current study aimed to evaluate the psychometric properties of the MDAS across gender and four major ethnic groups of Caucasian, Black, Asian and Hispanic, including reliability and concurrent validity against the Centre for Epidemiological Studies Depression Scale (CESD) and Patients Health Questionnaire (PHQ-9). It also aimed to establish a stable factor structure across gender and ethnic groups and test the measurement invariance to enhance its potential for clinical use. METHODS A community sample of 3499 participants from four ethnic groups were recruited via online crowdsourcing sites of Qualtrics and Amazon M Turk. Each individual completed a demographic questionnaire, the MDAS, CESD and PHQ-9. RESULTS There was good internal consistency (Cronbach's alpha >0.90) and concurrent reliability across gender and ethnic groups. Strict measurement invariance was established for MDAS over a four-factor factor structure corresponding to the four subscales. CONCLUSIONS The MDAS showed good psychometric properties and measurement invariance of a four-factor structure, suggesting its potential to be used in clinical settings across gender and ethnic groups. LIMITATIONS Participants all answered the questionnaires in English, which could hinder cultural variations in their expression of symptoms.
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Affiliation(s)
- H N Cheung
- School of Arts and Social Sciences, Hong Kong Metropolitan University, Hong Kong.
| | - Joanne M Williams
- Department of Clinical Psychology, University of Edinburgh, United Kingdom
| | - Y S Chan
- School of Applied Social Studies, Hong Kong Polytechnic University, Hong Kong
| | - Stella W Y Chan
- School of Psychology and Clinical Language Sciences, University of Reading, United Kingdom
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3
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Chan YS, Yiu MK. En-bloc paediatric dual kidney transplantation in Hong Kong: a case series and literature review. Hong Kong Med J 2018; 24:532-534. [PMID: 30318479 DOI: 10.12809/hkmj166061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Y S Chan
- Division of Urology, Department of Surgery, Queen Mary Hospital, Pokfulam, Hong Kong
| | - M K Yiu
- Division of Urology, Department of Surgery, Queen Mary Hospital, Pokfulam, Hong Kong
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4
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Chan YS, Khoo KS, Sit NWW. Investigation of twenty selected medicinal plants from Malaysia for anti-Chikungunya virus activity. Int Microbiol 2018; 19:175-182. [PMID: 28494087 DOI: 10.2436/20.1501.01.275] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Accepted: 09/30/2016] [Indexed: 11/15/2022]
Abstract
Chikungunya virus is a reemerging arbovirus transmitted mainly by Aedes mosquitoes. As there are no specific treatments available, Chikungunya virus infection is a significant public health problem. This study investigated 120 extracts from selected medicinal plants for anti-Chikungunya virus activity. The plant materials were subjected to sequential solvent extraction to obtain six different extracts for each plant. The cytotoxicity and antiviral activity of each extract were examined using African monkey kidney epithelial (Vero) cells. The ethanol, methanol and chloroform extracts of Tradescantia spathacea (Commelinaceae) leaves showed the strongest cytopathic effect inhibition on Vero cells, resulting in cell viabilities of 92.6% ± 1.0% (512 μg/ml), 91.5% ± 1.7% (512 μg/ml) and 88.8% ± 2.4% (80 μg/ml) respectively. However, quantitative RT-PCR analysis revealed that the chloroform extract of Rhapis excelsa (Arecaceae) leaves resulted in the highest percentage of reduction of viral load (98.1%), followed by the ethyl acetate extract of Vernonia amygdalina (Compositae) leaves (95.5%). The corresponding 50% effective concentrations (EC50) and selectivity indices for these two extracts were 29.9 ± 0.9 and 32.4 ± 1.3 μg/ml, and 5.4 and 5.1 respectively. Rhapis excelsa and Vernonia amygdalina could be sources of anti-Chikungunya virus agents. [Int Microbiol 19(3):175-182 (2016)].
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Affiliation(s)
- Yik Sin Chan
- Department of Biomedical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Kampar, Perak, Malaysia
| | - Kong Soo Khoo
- Department of Chemical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Kampar, Perak, Malaysia
| | - Nam Weng Weng Sit
- Department of Biomedical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Kampar, Perak, Malaysia
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5
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Yan BPY, Chan LLY, Lai WHS, To OTL, Chan YS, Wu EB. P795Paired propensity matched study of optical coherence tomography guided PCI for STEMI compared to intravascular ultrasound and angiography-only guided PCI. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy564.p795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- B P Y Yan
- The Chinese University of Hong Kong, Medicine & Therapeutics, Hong Kong, Hong Kong SAR People's Republic of China
| | - L L Y Chan
- The Chinese University of Hong Kong, Medicine & Therapeutics, Hong Kong, Hong Kong SAR People's Republic of China
| | - W H S Lai
- The Chinese University of Hong Kong, Medicine & Therapeutics, Hong Kong, Hong Kong SAR People's Republic of China
| | - O T L To
- The Chinese University of Hong Kong, Medicine & Therapeutics, Hong Kong, Hong Kong SAR People's Republic of China
| | - Y S Chan
- The Chinese University of Hong Kong, Medicine & Therapeutics, Hong Kong, Hong Kong SAR People's Republic of China
| | - E B Wu
- Prince of Wales University Hospital, Medicine & Therapeutics, Hong Kong, Hong Kong SAR People's Republic of China
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6
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Sit NW, Chan YS, Lai SC, Lim LN, Looi GT, Tay PL, Tee YT, Woon YY, Khoo KS, Ong HC. In vitro antidermatophytic activity and cytotoxicity of extracts derived from medicinal plants and marine algae. J Mycol Med 2018; 28:561-567. [PMID: 30060991 DOI: 10.1016/j.mycmed.2018.07.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 07/06/2018] [Accepted: 07/08/2018] [Indexed: 11/28/2022]
Abstract
OBJECTIVES This study was conducted to evaluate the antidermatophytic activity of 48 extracts obtained from medicinal plants (Cibotium barometz, Melastoma malabathricum, Meuhlenbeckia platyclada, Rhapis excelsa, Syzygium myrtifolium, Vernonia amygdalina) and marine algae (Caulerpa sertularioides, Kappaphycus alvarezii) against Trichophyton rubrum and Trichophyton interdigitale (ATCC reference strains), and the cytotoxicity using African monkey kidney epithelial (Vero) cells. Active plant extracts were screened for the presence of phytochemicals and tested against clinical isolates of Trichophyton tonsurans. METHODS Six different extracts (hexane, chloroform, ethyl acetate, ethanol, methanol and water) were obtained from each plant or algae sample using sequential solvent extraction. The antidermatophytic activity for the extracts was assessed using a colourimetric broth microdilution method. The viability of Vero cells was measured by Neutral Red uptake assay. RESULTS All the extracts (except the water extracts of V. amygdalina, C. sertularioides and K. alvarezii) showed antidermatophytic activity against Trichophyton spp. The minimum fungicidal concentration (MFC) ranges for the plant extracts against T. rubrum and T. interdigitale are 0.0025-2.50 and 0.005-2.50mg/mL, respectively. The algae extracts exhibited lower potency against both species, showing MFC ranges of 0.08-2.50 and 0.31-2.50mg/mL, respectively. The ethanol and methanol extracts from the leaves of R. excelsa, and the methanol and water extracts from the leaves of S. myrtifolium were highly active (MFC<0.1mg/mL) and with high selectivity indices (SI>2.8) against reference strains of T. rubrum and T. interdigitale, and most of the clinical isolates of T. tonsurans. Phytochemical analysis indicates the presence of alkaloids, anthraquinones, flavonoids, saponins, tannins, phenolics and triterpenoids in the extracts. CONCLUSIONS The medicinal plant extracts exhibited stronger antidermatophytic activity compared to the algae extracts. The leaves of R. excelsa and S. myrtifolium are potential sources of new antidermatophytic agents against Trichophyton spp.
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Affiliation(s)
- N W Sit
- Department of Biomedical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Bandar Barat, 31900 Kampar, Perak, Malaysia.
| | - Y S Chan
- Department of Biomedical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Bandar Barat, 31900 Kampar, Perak, Malaysia
| | - S C Lai
- Department of Biomedical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Bandar Barat, 31900 Kampar, Perak, Malaysia
| | - L N Lim
- Department of Biomedical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Bandar Barat, 31900 Kampar, Perak, Malaysia
| | - G T Looi
- Department of Biomedical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Bandar Barat, 31900 Kampar, Perak, Malaysia
| | - P L Tay
- Department of Biomedical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Bandar Barat, 31900 Kampar, Perak, Malaysia
| | - Y T Tee
- Department of Biomedical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Bandar Barat, 31900 Kampar, Perak, Malaysia
| | - Y Y Woon
- Department of Biomedical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Bandar Barat, 31900 Kampar, Perak, Malaysia
| | - K S Khoo
- Department of Chemical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Bandar Barat, 31900 Kampar, Perak, Malaysia
| | - H C Ong
- Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
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7
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Abstract
Our goal is to derive phenotypically stable Schwann cells from bone marrow stromal cells (BMSCs) for use in transplantation studies of central/peripheral nerve injuries. With the adult rat as model, here we describe steps that foster (1) expansion of the BMSC subpopulation of neural progenitors as neurosphere cells, (2) differentiation of the progenitors into Schwann cell-like cells in adherent culture supplemented with soluble factors, and (3) cell-intrinsic switch of Schwann cell-like cells to the Schwann cell fate following co-culture with sensory neurons purified from dorsal root ganglia. The derived Schwann cells retain marker expression despite withdrawal of supplements and neuronal cues, survive passaging and cryopreservation, and, importantly, show functional capacity for myelination.
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Affiliation(s)
- Y P Tsui
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Graham K Shea
- Department of Orthopaedics and Traumatology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Y S Chan
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Daisy K Y Shum
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
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8
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Chan YS, Cheah YH, Chong PZ, Khor HL, Teh WS, Khoo KS, Ong HC, Sit NW. Antifungal and cytotoxic activities of selected medicinal plants from Malaysia. Pak J Pharm Sci 2018; 31:119-127. [PMID: 29348093] [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: 06/07/2023]
Abstract
This study was conducted to investigate the antifungal potential and cytotoxicity of selected medicinal plants from Malaysia. The extracts from the stem of Cissus quadrangularis and the leaves of Asplenium nidus, Pereskia bleo, Persicaria odorata and Sauropus androgynus were assayed against six fungi using p-iodonitrotetrazolium-based on colorimetric broth microdilution method. All the plant extracts were found to be fungicidal against at least one type of fungus. The strongest fungicidal activity (minimum fungicidal concentration=0.16 mg/mL) were exhibited by the hexane extract of C. quadrangularis, the hexane, chloroform, ethanol and methanol extracts of P. bleo, the hexane and ethyl acetate extracts of P. odorata, and the water extract of A. nidus. In terms of cytotoxicity on the African monkey kidney epithelial (Vero) cells, the chloroform extract of P. odorata produced the lowest 50% cytotoxic concentration (100.3 ± 4.2 μ g/mL). In contrast, none of the water extracts from the studied plants caused significant toxicity on the cells. The water extract of A. nidus warrants further investigation since it showed the strongest fungicidal activity and the highest total activity (179.22 L/g) against Issatchenkia orientalis, and did not cause any toxicity to the Vero cells.
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Affiliation(s)
- Yik Sin Chan
- Department of Biomedical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Bandar Barat, Kampar, Perak, Malaysia
| | - Yit Hong Cheah
- Department of Biomedical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Bandar Barat, Kampar, Perak, Malaysia
| | - Poh Zen Chong
- Department of Biomedical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Bandar Barat, Kampar, Perak, Malaysia
| | - Hui Lai Khor
- Department of Biomedical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Bandar Barat, Kampar, Perak, Malaysia
| | | | - Kong Soo Khoo
- Department of Biomedical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Bandar Barat, Kampar, Perak, Malaysia
| | - Hean Chooi Ong
- Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
| | - Nam Weng Sit
- Department of Biomedical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Bandar Barat, Kampar, Perak, Malaysia
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9
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Kwok J, Ho JCY, Chan YS, Soormally A, Marsh SGE. Identification of the novel HLA-B*39:01:01:04 allele in a Chinese individual by sequence-based typing. HLA 2017; 89:115-117. [PMID: 28102040 DOI: 10.1111/tan.12958] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 12/22/2016] [Indexed: 11/30/2022]
Abstract
The new HLA-B*39:01:01:04 allele differs from HLA-B*39:01:01 by a C → T substitution in intron 1.
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Affiliation(s)
- J Kwok
- Division of Transplantation and Immunogenetics, Department of Pathology and Clinical Biochemistry, Queen Mary Hospital, Hong Kong
| | - J C Y Ho
- Division of Transplantation and Immunogenetics, Department of Pathology and Clinical Biochemistry, Queen Mary Hospital, Hong Kong
| | - Y S Chan
- Division of Transplantation and Immunogenetics, Department of Pathology and Clinical Biochemistry, Queen Mary Hospital, Hong Kong
| | - A Soormally
- Anthony Nolan Research Institute, Royal Free Hospital, London, UK
| | - S G E Marsh
- Anthony Nolan Research Institute, Royal Free Hospital, London, UK.,UCL Cancer Institute, University College London, London, UK
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10
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Wong JH, Ng TB, Cheung RC, Dan X, Chan YS, Hui M. Antimicrobial activity of cathelicidin peptides and defensin against oral yeast and bacteria. Hong Kong Med J 2016; 22 Suppl 7:37-40. [PMID: 29941692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023] Open
Affiliation(s)
- J H Wong
- School of Biomedical Sciences, The Chinese University of Hong Kong
| | - T B Ng
- School of Biomedical Sciences, The Chinese University of Hong Kong
| | - R Cf Cheung
- School of Biomedical Sciences, The Chinese University of Hong Kong
| | - X Dan
- School of Biomedical Sciences, The Chinese University of Hong Kong
| | - Y S Chan
- School of Biomedical Sciences, The Chinese University of Hong Kong
| | - M Hui
- Department of Microbiology, The Chinese University of Hong Kong
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11
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Wong JH, Ng TB, Hui M, Cheung RC, Chan YS, Dan X, Wang HX. Screening of aqueous and organic extracts from a variety of fungi for their ability to antagonise the pathogenic yeast Candida albicans. Hong Kong Med J 2016; 22 Suppl 7:26-29. [PMID: 29941689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023] Open
Affiliation(s)
- J H Wong
- School of Biomedical Sciences, The Chinese University of Hong Kong
| | - T B Ng
- School of Biomedical Sciences, The Chinese University of Hong Kong
| | - M Hui
- Department of Microbiology, The Chinese University of Hong Kong
| | - R Cf Cheung
- School of Biomedical Sciences, The Chinese University of Hong Kong
| | - Y S Chan
- School of Biomedical Sciences, The Chinese University of Hong Kong
| | - X Dan
- School of Biomedical Sciences, The Chinese University of Hong Kong
| | - H X Wang
- State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing, China
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12
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Kwok J, Guo M, Yang W, Lee CK, Ho J, Tang WH, Chan YS, Middleton D, Lu LW, Chan GCF. HLA-A, -B, -C, and -DRB1 genotyping and haplotype frequencies for a Hong Kong Chinese population of 7595 individuals. Hum Immunol 2016; 77:1111-1112. [PMID: 27769748 DOI: 10.1016/j.humimm.2016.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 10/12/2016] [Accepted: 10/17/2016] [Indexed: 10/20/2022]
Abstract
HLA-A, -B, -C and -DRB1 gene and haplotype frequencies have been calculated from 7595 southern Chinese unrelated donors in a Hong Kong Bone Marrow Donor Registry. This is the first large-scale paper to report the distribution of A-C-B-DRB1 alleles in Hong Kong Chinese. This information is important for phylogenetic, comparative studies and estimating the optimal and cost-effective donor size and likelihood of obtaining appropriately matched donors for Chinese patients awaiting haematopoietic stem cell transplantation. The allele and haplotype data are available in the Allele Frequencies Net Database under the population name ''Hong Kong Chinese BMDR'' and the identifier (AFND003357).
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Affiliation(s)
- Janette Kwok
- Division of Transplantation and Immunogenetics, Queen Mary Hospital, Hong Kong.
| | - Mengbiao Guo
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong
| | - Wanling Yang
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong
| | - C K Lee
- Hong Kong Red Cross Blood Transfusion Services, Hong Kong
| | - Jenny Ho
- Division of Transplantation and Immunogenetics, Queen Mary Hospital, Hong Kong
| | - W H Tang
- Division of Transplantation and Immunogenetics, Queen Mary Hospital, Hong Kong
| | - Y S Chan
- Division of Transplantation and Immunogenetics, Queen Mary Hospital, Hong Kong
| | - Derek Middleton
- Transplant Immunology, Royal Liverpool Hospital, Liverpool, UK
| | - L W Lu
- Department of Pathology, The University of Hong Kong, Hong Kong
| | - Godfrey C F Chan
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong
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13
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Kwok J, Guo M, Yang W, Lee CK, Chan NK, Ho J, Tang WH, Chan YS, Middleton D, Lu LW, Chan GCF. HLA-A, -B and -DRB1 genotyping and haplotype frequencies of 3892 cord blood units in the Hong Kong Chinese Cord Blood Registry. Hum Immunol 2016; 77:1109-1110. [PMID: 27769747 DOI: 10.1016/j.humimm.2016.10.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 10/12/2016] [Accepted: 10/17/2016] [Indexed: 11/25/2022]
Abstract
HLA-A, -B and -DRB1 gene and haplotype frequencies have been calculated from 3892 southern Chinese unrelated cord blood units in a Hong Kong Cord Blood Registry. This is the first large-scale paper to report the distribution of A-B-DRB1 alleles in Hong Kong Chinese Cord Blood Units. This information is important for estimating the optimal and economically cost-effective donor size and likelihood of obtaining appropriately matched cord blood units for Chinese patients awaiting haematopoietic stem cell transplantation. The data are available in the Allele Frequencies Net Database under the population name ''Hong Kong Chinese Cord Blood Registry'' and the identifier (AFND003358).
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Affiliation(s)
- Janette Kwok
- Division of Transplantation and Immunogenetics, Queen Mary Hospital, Hong Kong.
| | - Mengbiao Guo
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong
| | - Wanling Yang
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong
| | - C K Lee
- Hong Kong Red Cross Blood Transfusion Service, Hong Kong
| | - N K Chan
- Hong Kong Red Cross Blood Transfusion Service, Hong Kong
| | - Jenny Ho
- Division of Transplantation and Immunogenetics, Queen Mary Hospital, Hong Kong
| | - W H Tang
- Division of Transplantation and Immunogenetics, Queen Mary Hospital, Hong Kong
| | - Y S Chan
- Division of Transplantation and Immunogenetics, Queen Mary Hospital, Hong Kong
| | - Derek Middleton
- Transplant Immunology, Royal Liverpool Hospital, Liverpool, UK
| | - L W Lu
- Department of Pathology, The University of Hong Kong, Hong Kong
| | - Godfrey C F Chan
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong
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14
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McVinish R, Pollett PK, Chan YS. A metapopulation model with Markovian landscape dynamics. Theor Popul Biol 2016; 112:80-96. [PMID: 27591978 DOI: 10.1016/j.tpb.2016.08.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Revised: 08/17/2016] [Accepted: 08/26/2016] [Indexed: 11/15/2022]
Abstract
We study a variant of Hanski's incidence function model that allows habitat patch characteristics to vary over time following a Markov process. The widely studied case where patches are classified as either suitable or unsuitable is included as a special case. For large metapopulations, we determine a recursion for the probability that a given habitat patch is occupied. This recursion enables us to clarify the role of landscape dynamics in the survival of a metapopulation. In particular, we show that landscape dynamics affects the persistence and equilibrium level of the metapopulation primarily through its effect on the distribution of a local population's life span.
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Affiliation(s)
- R McVinish
- School of Mathematics and Physics, University of Queensland, Australia.
| | - P K Pollett
- School of Mathematics and Physics, University of Queensland, Australia
| | - Y S Chan
- School of Mathematics and Physics, University of Queensland, Australia
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15
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Kumar AA, Jaison J, Prabakaran K, Nagarajan R, Chan YS. Water quality monitoring: A comparative case study of municipal and Curtin Sarawak's lake samples. ACTA ACUST UNITED AC 2016. [DOI: 10.1088/1757-899x/121/1/012019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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16
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Kwok J, Ho JCY, Chan YS, Soormally A, Marsh SGE. Identification of a novel HLA-A*02:06:01:02 allele in a Chinese individual by sequence-based typing. ACTA ACUST UNITED AC 2015; 86:448-9. [PMID: 26593753 DOI: 10.1111/tan.12691] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 10/03/2015] [Indexed: 11/25/2022]
Abstract
The new HLA-A*02:06:01:02 allele differs from HLA-A*02:06:01 by a C→G substitution in Intron 1.
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Affiliation(s)
- J Kwok
- Division of Transplantation and Immunogenetics, Department of Pathology and Clinical Biochemistry, Queen Mary Hospital, Hong Kong SAR, China
| | - J C Y Ho
- Division of Transplantation and Immunogenetics, Department of Pathology and Clinical Biochemistry, Queen Mary Hospital, Hong Kong SAR, China
| | - Y S Chan
- Division of Transplantation and Immunogenetics, Department of Pathology and Clinical Biochemistry, Queen Mary Hospital, Hong Kong SAR, China
| | - A Soormally
- Anthony Nolan Research Institute, Royal Free Hospital, London, UK
| | - S G E Marsh
- Anthony Nolan Research Institute, Royal Free Hospital, London, UK.,UCL Cancer Institute, University College London, London, UK
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17
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Simoni A, Siniscalchi C, Chan YS, Huen DS, Russell S, Windbichler N, Crisanti A. Development of synthetic selfish elements based on modular nucleases in Drosophila melanogaster. Nucleic Acids Res 2015; 43:2991. [PMID: 25675957 PMCID: PMC4357718 DOI: 10.1093/nar/gkv117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Wong JH, Ip DCW, Ng TB, Chan YS, Fang F, Pan WL. A defensin-like peptide from Phaseolus vulgaris cv. 'King Pole Bean'. Food Chem 2012; 135:408-14. [PMID: 22868107 DOI: 10.1016/j.foodchem.2012.04.119] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 03/22/2012] [Accepted: 04/23/2012] [Indexed: 11/16/2022]
Abstract
A 5447 Da antifungal peptide with an N-terminal sequence highly homologous to plant defensins was purified from Phaseolus vulgaris cv. 'King Pole Bean' by anion-exchange chromatography on Q Sepharose and FPLC-gel filtration on Superdex 75. The isolated peptide inhibited growth of a number of fungal species, including Mycosphaerella arachidicola, Saccharomyces cerevisiae and Candida albicans, with IC(50) values of 3.9, 4.0 and 8.4 μM, respectively. Using the membrane non-permeable DNA-binding dye SYTOX green, it was found that the peptide increased the cell membrane permeability of M. arachidicola, S. cerevisiae and C. albicans.
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Affiliation(s)
- Jack H Wong
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong.
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Gao JL, Cheung RTF, Chan YS, Chu LW, Lee TMC. Increased prospective memory interference in normal and pathological aging: different roles of motor and verbal processing speed. Neuropsychol Dev Cogn B Aging Neuropsychol Cogn 2012; 20:80-100. [PMID: 22486785 DOI: 10.1080/13825585.2012.672948] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
This is a study on prospective memory (PM) and the PM interference effect in normal and pathological aging. One hundred and seven subjects, including 41 healthy young adults, 40 non-demented older adults and 26 patients with mild Alzheimer's disease (AD) participated in this study using a laboratory event-based PM task. PM task performance was comparable between the non-demented older and young adults, but impaired in the AD patients. The PM interference effect increased progressively from the healthy young adults, the non-demented older adults, to the AD patients. Path analysis revealed that the possible mechanism mediating the increased PM interference was the slow motor processing speed in normal aging, while it was the slow verbal speed in pathological aging. It is suggested that different neuropsychological mechanisms may underpin the affected performance of PM task in normal and pathological aging.
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Affiliation(s)
- J L Gao
- Department of Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong
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21
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Ng OTW, Chen LW, Chan YS, Yung KKL. Small interfering RNA specific for N-methyl-D-aspartate receptor 2B offers neuroprotection to dopamine neurons through activation of MAP kinase. Neurosignals 2012; 21:42-54. [PMID: 22377595 DOI: 10.1159/000334720] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 10/27/2011] [Indexed: 11/19/2022] Open
Abstract
In the present study, N-methyl-D-aspartate receptor 2B (NR2B)-specific siRNA was applied in parkinsonian models. Our previous results showed that reduction in expression of N-methyl-D-aspartate receptor 1 (NR1), the key subunit of N-methyl-D-aspartate receptors, by antisense oligos ameliorated the motor symptoms in the 6-hydroxydopamine (6-OHDA)-lesioned rat, an animal model of Parkinson's disease (PD).
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Affiliation(s)
- Olivia T W Ng
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
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Chu JMT, Chen LW, Chan YS, Yung KKL. Neuroprotective effects of neurokinin receptor one in dopaminergic neurons are mediated through Akt/PKB cell signaling pathway. Neuropharmacology 2011; 61:1389-98. [PMID: 21907219 DOI: 10.1016/j.neuropharm.2011.08.027] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 07/25/2011] [Accepted: 08/18/2011] [Indexed: 11/29/2022]
Abstract
Neurokinin one (NK1) receptor is Substance P (SP) receptor and it is abundantly distributed in the basal ganglia. Growing evidences were shown on their possible roles in the pathogenesis and treatment of Parkinson's disease (PD). NK1 receptor is a kind of G-protein-coupled-receptor (GPCR) and it links to various downstream survival signaling pathways. In the present study, treatment of NK1 receptor agonist septide [(Pyr6, Pro9)-SP (6-11)] was found to ameliorate the motor deficit in 6-hydroxydopamine (6-OHDA) lesioned rats in apomorphine rotation test. Septide treatments were also demonstrated to provide neuroprotection. In 6-OHDA lesioned rats, protection of TH immunoreactive neurons and terminals in substantia nigra (SN) and striatum was found after septide treatment. In SH-SY5Y cultures, cytotoxicity of 6-OHDA was reduced by septide pretreatment. In addition, up-regulations of phosphorylated serine-threonine kinase Akt and phosphorylated mitochondrial apoptotic protein BAD were observed in both in vivo and in vitro models, indicating the inhibition of apoptotic pathway by septide. In conclusion, septide could trigger the pro-survival Akt/PKB signaling pathway and protect dopaminergic neurons in in vivo and in vitro models against 6-OHDA toxicity. Therefore septide treatment may have therapeutic implications in treatment of PD.
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Affiliation(s)
- John M T Chu
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong
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Abstract
A lectin specific for glucuronic acid and galacturonic acid has been isolated from seeds of the French bean Phaseolus vulgaris using a procedure that involved affinity chromatography on Affi-gel blue gel, fast protein liquid chromatography (FPLC)-ion exchange chromatography on Mono S, and FPLC-gel filtration on Superdex 200. The lectin was comprised of two 32-kDa subunits with substantial N-terminal sequence similarity to other Phaseolus lectins. The hemagglutinating activity of the lectin was stable within the pH range of 1-13 and the temperature range of 10-60 degrees C. The lectin neither exhibited any antiproliferative activity against tumor cells nor stimulated nitric oxide production by murine peritoneal macrophages at doses as high as 1mM, The lectin failed to evoke any mitogenic response from murine splenocytes as measured by [(3)H-methyl]-thymidine incorporation and did not inhibit the activity of HIV-1 reverse transcriptase. The lectin had no antifungal activity.
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Affiliation(s)
- A Sharma
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
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24
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Abstract
Patients with systemic lupus erythematosus (SLE) frequently received corticosteroid therapy, resulting in osteonecrosis of the femoral head (ONFH). Prior studies demonstrated the effectiveness of extracorporeal shockwave treatment (ESWT) for ONFH.. This study evaluated the effectiveness of ESWT for ONFH in patients with SLE. We studied 39 patients, including 15 patients with SLE (26 hips) and 24 controls (29 hips). To each affected hip we applied ESWT (6000 impulses at 28 kV in a single session). Patients were ambulated with partial weight bearing for 4-6 weeks. The primary endpoint was the need for hip replacement. The secondary endpoints were improvement in hip pain and function and image changes on X-ray and MRI. Patients received total hip replacement in 12% of patients with SLE and in 14% of controls (P = 0.802). There was no statistically significant difference in pain scores (0.86 vs. 0.89; P = 0.467) and function scores (89% vs. 91%; P = 0.194) between patients with SLE and controls. SLE response to ESWT for ONFH is comparable with ONFH in patients without SLE.
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Affiliation(s)
- C J Wang
- Department of Orthopedic Surgery, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Taiwan.
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Gao JL, Cheung RTF, Lee TMC, Chan YS, Chu LW. Different neural correlates of speed and accuracy in choice response time task: VBM study on groups of the young, the elderly and the demented. Neuroimage 2009. [DOI: 10.1016/s1053-8119(09)70661-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Chen L, Yung KKL, Chan YS, Yung WH. 5-HT excites globus pallidus neurons by multiple receptor mechanisms. Neuroscience 2007; 151:439-51. [PMID: 18082329 DOI: 10.1016/j.neuroscience.2007.11.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Revised: 10/31/2007] [Accepted: 11/30/2007] [Indexed: 11/26/2022]
Abstract
Anatomical and neurochemical studies indicated that the globus pallidus receives serotonergic innervation from raphe nuclei but the membrane effects of 5-HT on globus pallidus neurons are not entirely clear. We address this question by applying whole-cell patch-clamp recordings on globus pallidus neurons in immature rat brain slices. Under current-clamp recording, 5-HT depolarized globus pallidus neurons and increased their firing rate, an action blocked by both 5-HT(4) and 5-HT(7) receptor antagonists and attributable to an increase in cation conductance(s). Further experiments indicated that 5-HT enhanced the hyperpolarization-activated inward conductance which is blocked by 5-HT(7) receptor antagonist. To determine if 5-HT exerts any presynaptic effects on GABAergic and glutamatergic inputs, the actions of 5-HT on synaptic currents were studied. At 10 microM, 5-HT increased the frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) but had no effect on both the frequency and amplitude of miniature inhibitory postsynaptic currents (mIPSCs). However, 5-HT at a higher concentration (50 microM) decreased the frequency but not the amplitude of the mIPSCs, indicating an inhibition of GABA release from the presynaptic terminals. This effect was sensitive to 5-HT(1B) receptor antagonist. In addition to the presynaptic effects on GABAergic neurotransmission, 5-HT at 50 microM had no consistent effects on glutamatergic neurotransmission, significantly increased the frequency of miniature excitatory postsynaptic currents (mEPSCs) in 4 of 11 neurons and decreased the frequency of mEPSCs in 3 of 11 neurons. In conclusion, we found that 5-HT could modulate the excitability of globus pallidus neurons by both pre- and post-synaptic mechanisms. In view of the extensive innervation by globus pallidus neurons on other basal ganglia nuclei, this action of 5-HT originated from the raphe may have a profound effect on the operation of the entire basal ganglia network.
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Affiliation(s)
- L Chen
- Department of Physiology, The Chinese University of Hong Kong, Shatin, Hong Kong, China
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Chu W, Chan KH, Jafvert CT, Chan YS. Removal of phenylurea herbicide monuron via riboflavin-mediated photosensitization. Chemosphere 2007; 69:177-83. [PMID: 17583771 DOI: 10.1016/j.chemosphere.2007.04.055] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2006] [Revised: 04/18/2007] [Accepted: 04/18/2007] [Indexed: 05/15/2023]
Abstract
Photodegradation of the phenylurea herbicide monuron by using riboflavin (Rf), a sensitizer, was investigated by varying the doses of monuron and Rf in this work. An enhanced photochemical effect was observed in the process compared with the direct photolysis by using UV irradiation only. The reaction time was greatly shortened from more than 60 min (direct photolysis) to 8-30 min depending on the doses of initial concentration of monuron ([M]0) and Rf. A modified hyperbola model was found to be useful to determine the reaction kinetics and thereafter the performance on the photodegradation of monuron sensitized by Rf. Two measurable characteristic constants (initial decay rate and total removal index) were used to quantify the reaction. The maximum removal difference compared with the direct photolysis and Rf-sensitization was investigated. It was found that the improvement of the process depended on both the [M]0 and the doses of Rf.
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Affiliation(s)
- W Chu
- Department of Civil and Structural Engineering, The Hong Kong Polytechnic University, Hunghom, Kowloon, Hong Kong.
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Chan YS, Chen ACY, Yuan LJ, Lin SS, Yang CY, Lee MSS, Ueng SWN. Effects of hyperbaric oxygen and platelet derived growth factor on medial collateral ligament fibroblasts. Undersea Hyperb Med 2007; 34:181-90. [PMID: 17672174] [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: 05/16/2023]
Abstract
PURPOSE This study investigated hyperbaric oxygen (HBO2) and platelet-derived growth factor-BB (PDGF-BB) to determine their combined effects on fibroblasts from rabbit medial collateral ligament (MCL). METHOD Cells were divided into four groups: (I) Control, (II) HBO2 treatment, (III) PDGF-BB treatment and (IV) HBO2 combined with PDGF-BB treatment. All hyperoxic cells were exposed to 100% O2 at 2.5 atmospheres absolute (ATA) in a hyperbaric chamber for 120 minutes per 48 hours. Measurement of cell growth was based on increase in cell number. Cell cycle modulations were analyzed by fluorescence-activated cell sorter (FACS). Quantity of Type I and Type III collagen was determined by western blotting and image analyzer. RESULTS Treatment doses of HBO2 alone or PDGF-bb alone dependently increased cell growth. A combination of HBO2 treatment plus PDGF-bb treatment had an additive effect on cell growth in comparison with HBO2 treatment alone or PDGF-bb treatment alone. FACS analysis revealed that HBO2 alone, PDGF-bb alone and PDGF-bb plus HBO2 treatment increase the percentage of cells accumulated in S-phase. Western blotting analysis revealed that Type III collagen content was decreased significantly after HBO2 treatment alone or HBO2 plus PDGF-bb treatment but not in PDGF-bb treatment alone. In contrast, although Type I collagen content was increased after HBO2 treatment, the increase in Type I collagen (increase /original) was not statistically significant. CONCLUSION HBO2 or HBO2 plus PDGF-bb treatment decreases the Type III collagen/Type I collagen content, which could result in mechanically stronger collagen fibrils. We propose HBO2 therapy as a potentially effective treatment for MCL healing.
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Affiliation(s)
- Y S Chan
- Department of Orthopaedic Surgery and Hyperbaric Oxygen Therapy Center, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, 5, Fu-Hsing St. 333, Kweishan, Taoyuan, Taiwan
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Chung EKY, Chen LW, Chan YS, Yung KKL. Up-regulation in expression of vesicular glutamate transporter 3 in substantia nigra but not in striatum of 6-hydroxydopamine-lesioned rats. Neurosignals 2007; 15:238-48. [PMID: 17435391 DOI: 10.1159/000101704] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [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: 01/19/2007] [Accepted: 02/12/2007] [Indexed: 11/19/2022] Open
Abstract
Overactivity of the glutamatergic system is suggested to be closely related to the onset and pathogenesis of Parkinson's disease. Vesicular glutamate transporters (VGLUT1, T2 and T3) are a group of glutamate transporters in neurons that are responsible for transporting glutamate into synaptic vesicles and they are key elements for homeostasis of glutamate neurotransmission. The present study was aimed to investigate the expression of VGLUT1, T2 and T3 proteins after the onset of Parkinson's disease. A rat model of Parkinson's disease, the 6-hydroxydopamine-lesioned rat, was employed. Immunocytochemistry revealed that VGLUT1, T2 and T3 immunoreactivity was not modulated in the striatum of the lesioned rat. Western blotting analyses also showed that there was no change in the expression of T1, T2 and T3 proteins in the striatum. In contrast, no VGLUT1 protein was detected in the substantia nigra. After the lesion, levels of VGLUT2 immunoreactivity and protein were not modulated. Significant increase of VGLUT3 immunoreactivity was observed in the perikarya of GABAergic substantia nigra pars reticulata neurons (+14.7%) although VGLUT3 protein was not modulated in the nigral tissues. VGLUT3 in GABAergic neurons is suggested to play a role in GABA synthesis. The present results may therefore implicate that VGLUT1 and T2 are not modulated in the striatum and the substantia nigra of the 6-hydroxydopamine-lesioned rat and only VGLUT3 plays a role in pathogenesis of Parkinson's disease.
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Affiliation(s)
- E K Y Chung
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong, PR China
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Leung KW, Yung KKL, Mak NK, Chan YS, Fan TP, Wong RNS. Neuroprotective effects of ginsenoside-Rg1 in primary nigral neurons against rotenone toxicity. Neuropharmacology 2006; 52:827-35. [PMID: 17123556 DOI: 10.1016/j.neuropharm.2006.10.001] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [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: 06/05/2006] [Revised: 09/30/2006] [Accepted: 10/03/2006] [Indexed: 12/21/2022]
Abstract
Ginsenoside-Rg1, the pharmacologically active component isolated from ginseng, demonstrated neuroprotective effects on primary cultured rat nigral neurons against rotenone toxicity. Rotenone, a common household pesticide known for its specific and irreversible mitochondria complex I inhibition, has been suggested to be the causal agent of Parkinson's disease (PD) by inducing degeneration of cells in the substantial nigra. The present study demonstrated that co-treatment of rotenone and Rg1 could reduce rotenone-induced cell death by 58% (SEM=+/-5.60; N=3). Rotenone-induced mitochondria membrane potential (MMP, DeltaPsim) depletion was restored and elevated by at least 38% (SEM=+/-2.15; N=3) by Rg1. In addition, Rg1 prevented cytochrome c release from the mitochrondrial membrane and increased the phosphorylation inhibition of the pro-apoptotic protein Bad through activation of the PI3K/Akt pathway. The protective effects of Rg1 was blocked by glucocorticoid receptor antagonist RU486, indicating that the action of Rg1 is mediated through glucocorticoid receptor (GR). In conclusion, Rg1 inhibits the mitochondrial apoptotic pathway and increases the survival chance of the primary cultured nigral neurons against rotenone toxicity. Thus, Rg1 and its related compounds may be developed as protective agents against neurodegenerative diseases induced by mitochondrial toxins.
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Affiliation(s)
- K W Leung
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong.
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Lui PW, Yeung CW, Yung WH, Shi Y, Chen LW, Chan YS, Yung KKL. Ablation of gene expression of N-methyl-D-aspartate receptor one by antisense oligonucleotides in striatal neurons in culture. Neurosignals 2006; 14:303-16. [PMID: 16772733 DOI: 10.1159/000093045] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [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: 10/17/2005] [Accepted: 02/28/2006] [Indexed: 11/19/2022] Open
Abstract
In the present study, a twenty-mer antisense oligonucleotide specific for N-methyl-D-aspartate receptor one (ANR1) was applied to striatal neurons in primary cell culture. The ANR1 was found to be specific and nontoxic. Significant reductions in expression of NR1 mRNA and proteins were resulted after a single dose of ANR1 transcripts. Interestingly, there were reductions in total NR1 proteins but two phosphorylated forms of NR1 proteins at serine 896 and 897 residues were not reduced. There was also no change in the pattern of distribution of NR1 immunoreactivity in the striatal neurons. In addition, significant reductions of NMDA-mediated peak inward current were found after application of a higher concentration of ANR1 (20-100 microM) by patch clamp recordings. The present results indicate that ANR1 is a useful agent in reducing NMDA receptor functions. The present data thus provide detailed cellular and molecular mechanisms to explain our previous findings of amelioration of motor symptoms in a rat model of Parkinson's disease. More importantly, application of ANR1 was also found to display neuroprotective effects of striatal neurons against NMDA-induced excitotoxic cell death. The findings have implications in development of new approach in prevention of cell death in neurodegenerative diseases and new treatments for these diseases.
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Affiliation(s)
- P W Lui
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, PR China
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Lee TMC, Zhang JX, Chan CCH, Yuen KSL, Chu LW, Cheung RTF, Chan YS, Fox PT, Gao JH. Age-related differences in response regulation as revealed by functional MRI. Brain Res 2006; 1076:171-6. [PMID: 16476418 DOI: 10.1016/j.brainres.2005.12.124] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2003] [Revised: 12/29/2005] [Accepted: 12/29/2005] [Indexed: 11/22/2022]
Abstract
This fMRI study studied age-related differences in neural activities during response regulation. Twenty-one male participants from two age groups, a younger group and an older group (mean ages: 29.9 and 65.2 years, respectively), were scanned while performing a task with response compatibility manipulation. They were presented with a sequence of arrowheads that pointed either upward or downward. In the "Response Compatible" condition, they were required to press an up or a down button consistent with the direction of the arrowhead. In the "Response Incompatible" condition, they were required to press the button opposite to the arrowhead direction so that an upward arrow should elicit a down response, and vice versa. Findings showed age-related differences in response regulation in several brain regions, including the right frontal, the right cingulate, and the left inferior parietal cortexes. The findings suggested a higher level of neural activity in the right prefrontal and left inferior parietal regions during response regulation for the older adults than for the younger adults.
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Affiliation(s)
- Tatia M C Lee
- Neuropsychology Laboratory, Department of Psychology, The University of Hong Kong, Hong Kong.
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Zhang FX, Lai CH, Li JL, Shum DKY, Chan YS. Tyrosine kinase receptor immunoreactivity in trigeminal mesencephalic and motor neurons following transection of masseteric nerve of the rat. Neuroscience 2006; 139:921-30. [PMID: 16517086 DOI: 10.1016/j.neuroscience.2006.01.036] [Citation(s) in RCA: 6] [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] [Received: 07/13/2005] [Revised: 12/23/2005] [Accepted: 01/16/2006] [Indexed: 01/19/2023]
Abstract
Neurotrophins are known to promote survival after neural injury. To determine the relative importance of tyrosine kinase receptors on the survival of axotomized trigeminal nuclear neurons, we examined the temporal expression profile of tyrosine kinase A, tyrosine kinase B and tyrosine kinase C receptors in the mesencephalic trigeminal nucleus and the motor trigeminal nucleus following transection of the masseteric nerve in rats. Axotomized neurons in these nuclei were retrogradely identified with FluoroGold. We found increase in tyrosine kinase A-immunoreactive mesencephalic trigeminal nucleus neurons in the second week after axotomy but no change in the number of tyrosine kinase A-immunoreactive motor trigeminal nucleus neurons. There was no change in the number of tyrosine kinase B-immunoreactive mesencephalic trigeminal nucleus neurons but the significant increase of tyrosine kinase B-immunoreactive motor trigeminal nucleus neurons throughout the period of observation (3 weeks) peaked at approximately 1 week after axotomy. There was no alteration in the number of tyrosine kinase C-immunoreactive mesencephalic trigeminal nucleus neurons but significant increase in tyrosine kinase C-immunoreactive motor trigeminal nucleus neurons observable by 4 days post-axotomy was followed by decline to levels lower than the control in 2 weeks. Temporal changes in the expression of individual tyrosine kinase receptors in mesencephalic trigeminal nucleus and motor trigeminal nucleus neurons following transection of the masseteric nerve suggest differential contribution of tyrosine kinase-specific neurotrophins to the survival of these neurons after axotomy.
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Affiliation(s)
- F X Zhang
- Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
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Chen LW, Tse YC, Li C, Guan ZL, Lai CH, Yung KKL, Shum DKY, Chan YS. Differential expression of NMDA and AMPA/KA receptor subunits in the inferior olive of postnatal rats. Brain Res 2006; 1067:103-14. [PMID: 16376317 DOI: 10.1016/j.brainres.2005.10.054] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [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: 05/23/2005] [Revised: 09/30/2005] [Accepted: 10/11/2005] [Indexed: 12/20/2022]
Abstract
We have employed immunohistochemistry to determine the expression patterns of receptor subunits of N-methyl-d-aspartate (NMDA-NR1 and NR2A/B) and alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid/kainic acid (AMPA/KA-GluR1, GluR2, GluR2/3, GluR4, and GluR5/6/7) in the inferior olive of postnatal rats up to adulthood. Immunoreactivity for distinct receptor subunits was predominantly localized in the soma and dendrites of neurons. Semi-quantification showed that the overall immunoreactivity in the inferior olive of adults was intense for GluR1, moderate for NR1 and NR2A/B, and low for GluR2, GluR2/3, GluR4, and GluR5/6/7. At P7, GluR1 was restricted to the dorsomedial cell column, subnucleus beta, principal nucleus and ventrolateral protrusion while the other subunits were found in all subnuclei of the inferior olive. The immunoreactivities for all glutamate receptor subunits ranged from low to moderate. As the rats matured, the immunoreactivity of GluR4 decreased after the second postnatal week, while those of the other subunits showed a general trend of increase, reaching adult level during the third postnatal week. Double immunofluorescence revealed that all NR1-containing neurons exhibited NR2A/B immunoreactivity, indicating that native NMDA receptors comprise of hetero-oligomeric combinations of NR1 and NR2A/B. Furthermore, co-localization of NMDA and AMPA/KA receptor subunits was demonstrated in individual neurons of the inferior olive. All NR1-containing neurons exhibited GluR1 immunoreactivity, and all NR2A/B-containing neurons showed GluR5/6/7 immunoreactivity. Our data suggest that NMDA and AMPA/KA receptors are involved in glutamate-mediated neurotransmission, contributing to synaptic plasticity and reorganization of circuitry in the inferior olive during postnatal development.
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Affiliation(s)
- L-W Chen
- Department of Physiology, Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, PR China
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Zhang FX, Lai CH, Tse YC, Shum DKY, Chan YS. Expression of Trk receptors in otolith-related neurons in the vestibular nucleus of rats. Brain Res 2005; 1062:92-100. [PMID: 16256078 DOI: 10.1016/j.brainres.2005.09.025] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2005] [Revised: 09/18/2005] [Accepted: 09/25/2005] [Indexed: 01/19/2023]
Abstract
The expression of the three Trk receptors (TrkA, TrkB, and TrkC) in otolith-related neurons within the vestibular nuclei of adult Sprague-Dawley rats was examined immunohistochemically. Conscious animals were subjected to sinusoidal linear acceleration along either the anterior-posterior (AP) or interaural (IA) axis on the horizontal plane. Neuronal activation was defined by Fos expression in cell nuclei. Control animals, viz labyrinthectomized rats subjected to stimulation and normal rats that remained stationary, showed only a few sporadically scattered Fos-labeled neurons. Among experimental rats, the number of Fos-labeled neurons and their distribution pattern in each vestibular subnucleus in animals stimulated along the antero-posterior axis were similar to those along the interaural axis. No apparent topography was observed among neurons activated along these two directions. Only about one-third of the Trk-immunoreactive neurons in the vestibular nucleus expressed Fos. Double-labeled Fos/TrkA, Fos/TrkB and Fos/TrkC neurons constituted 85-98% of the total number of Fos-labeled neurons in vestibular nuclear complex and its subgroups x and y. Our findings suggest that Trk receptors and their cognate neurotrophins in central otolith neurons may contribute to the modulation of gravity-related spatial information during horizontal head movements.
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Affiliation(s)
- F X Zhang
- Department of Physiology, Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, China
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Lee MS, Tu YK, Chao CCK, Chen SC, Chen CY, Chan YS, Yeh WL, Ueng SWN. Inhibition of nitric oxide can ameliorate apoptosis and modulate matrix protein gene expression in bacteria infected chondrocytes in vitro. J Orthop Res 2005; 23:440-5. [PMID: 15734260 DOI: 10.1016/j.orthres.2004.06.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2003] [Accepted: 06/18/2004] [Indexed: 02/04/2023]
Abstract
Bacterial infection stimulates nitric oxide (NO) production in chondrocytes. However, the role of NO in chondrocyte apoptosis after infection remains unclear. The purpose of the study was to test if inhibition of NO could ameliorate apoptosis and modulate matrix protein gene expression in bacteria-infected chondrocytes. It was shown that pre-treating chondrocytes with L-NAME (1 mM) significantly decreased the release of NO (from 72 to 14 microM) and the extent of apoptosis (from 52.9% to 18.9%). Pre-treatment with L-NAME also counteracted the bacteria-induced downregulation of Type II collagen (from 26% to 79%) and aggrecan (from 63% to 105%) mRNA levels. Inhibition of NO after the induction of infection could not decrease the extent of apoptosis and modulate matrix protein gene expression. The results of this study support the hypothesis that NO has an important role in bacteria-induced chondrocyte apoptosis. Pre-treatment but not post-treatment could ameliorate the extent of apoptosis and reestablish the cartilage matrix protein gene expression. This study suggests that in addition to NO, other mechanisms may be responsible for the sustained destruction of articular cartilage in the post-infectious arthropathy.
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Affiliation(s)
- M S Lee
- Department of Orthopaedic Surgery, Chang Gung Memorial Hospital, No. 222, Mai-chin Road, Keelung, Taiwan
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Abstract
OBJECTIVE To examine teachers' views of the first batch of graduates of a revised medical curriculum in Asia. METHODS A cross-sectional study using a structured questionnaire was carried out to obtain the views of all the clinical teachers involved in teaching final year students of the old curriculum in 2000-01 and the new curriculum in 2001-02 at the University of Hong Kong, which commenced curricular reform in 1997. RESULTS Nearly 62% of respondents felt that better graduates were being produced with the new curriculum. The majority of them rated the new curriculum students better in nearly all the major goals of the new curriculum, such as self-directed learning initiative, problem solving skills, interpersonal skills and clinical performance in patient care. However, the core knowledge of the new curriculum students was of concern to some teachers. CONCLUSION This study focused on the first complete cycle of a revised medical curriculum in Asia. Teachers' views of the new curriculum students were highly positive and they felt that better graduates were being produced.
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Affiliation(s)
- T P Lam
- Family Medicine Unit, Department of Medicine, University of Hong Kong, 3/F Ap Lei Chau Clinic, 161 Main Street, Ap Lei Chau, Hong Kong, China.
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Hu HJ, Chen LW, Yung KKL, Chan YS. Differential expression of AMPA receptor subunits in substance P receptor-containing neurons of the caudate-putamen of rats. Neurosci Res 2004; 49:281-8. [PMID: 15196776 DOI: 10.1016/j.neures.2004.03.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [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: 11/11/2003] [Accepted: 03/11/2004] [Indexed: 10/26/2022]
Abstract
Previous evidence has suggested that glutamate-driving neurotransmission and glutamate-excitotoxicity are modulated by substance P in the basal ganglia, but the assembly of glutamate receptors mediating this process remains to be delineated. By using a double immunofluorescence, cellular expression of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptor subunits (GluR1-4) in substance P receptor (SPR)-containing neurons was examined in the striatum of rats. It revealed that distribution of SPR-immunoreactive neurons completely overlapped with that of GluR1, 2, 3 or 4-immunoreactive neurons in the caudate-putamen. Neurons showing both SPR and AMPA receptor subunits (except of GluR3)-immunoreactivity were observed: all (100%) of SPR-positive neurons displayed GluR1-, GluR2- or GluR4-immunoreactivity, and the double-labeled neurons constituted about 33, 3 or 29% of total GluR-positive ones. In contrast, the neurons exhibiting both SPR- and GluR3-immunoreactivity were not detected, though numerous GluR3-positive neurons were still distributed in the caudate-putamen regions. Co-localization of SPR and distinct AMPA receptor subunits in the striatal neurons has provided a basis for functional modulation of neuronal APMA receptors by substance P in the caudate-putamen of rodents. Taken together with previous observations, this study has also suggested that, through interaction with AMPA receptors composed of subunits 1, 2 and 4, substance P or neurokinin peptides may play important roles in regulating neuronal properties and protecting neurons from excitotoxicity in the basal ganglia of mammals.
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Affiliation(s)
- H-J Hu
- Institute of Neurosciences, The Fourth Military Medical University, Xi'an 710032, PR China
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Lai SK, Ng TKY, Lau WK, Yang MS, Wong CKC, Chan YS, Yung KKL. Selective knockdown of gene expression of N-methyl-D-aspartate receptor one ameliorates parkinsonian motor symptom in 6-hydroxydopamine-lesioned rats. Neurochem Int 2004; 45:11-22. [PMID: 15082217 DOI: 10.1016/j.neuint.2004.01.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [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: 04/15/2003] [Revised: 12/30/2003] [Accepted: 01/14/2004] [Indexed: 11/27/2022]
Abstract
The present study reported the efficacy of antisense oligonucleotides specific for N-methyl-D-aspartate receptor one (NR1) in reduction of motor symptom in a rat parkinsonian model, the unilateral 6-hydroxydopamine-lesioned rat. Significant reductions in apomorphine-induced contralateral rotation were only seen in the NR1 antisense-treated lesioned rats (after a single intraparenchymal dose of antisense to the lesioned neostriatum; 15 nmol in 3 microl of saline) at 1 or 2 days after the treatment. No motor effect was seen in the lesioned animals with control treatments (sham, treatment using NR1 sense oligonucleotides, randomized oligonucleotides or saline, respectively). In contrast, significant increases in expression of NR1 mRNA in the lesioned neostriatum were seen in rats with control treatments but not in rats with NR1 antisense treatment. Importantly, in the lesioned neostriatum that was treated with NR1 antisense, a significant reduction in NR1 protein expression was found and NR1 immunoreactivity was seen to reduce in perikarya of presumed striatal medium spiny neurons. The present data indicate that a single dose of NR1 antisense ameliorates motor symptom in the rat model. The efficacy of NR1 antisense is likely to be mediated by a selective knockdown in expression of NR1 mRNA and proteins in the presumed medium spiny neurons.
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Affiliation(s)
- S K Lai
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong, PR China
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40
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Chen LW, Yung KKL, Chan YS. Neurokinin peptides and neurokinin receptors as potential therapeutic intervention targets of basal ganglia in the prevention and treatment of Parkinson's disease. Curr Drug Targets 2004; 5:197-206. [PMID: 15011953 DOI: 10.2174/1389450043490596] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [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: 11/22/2022]
Abstract
Parkinson's disease (PD) is a serious motor disorder and it is the second most common brain degenerative disease in human. PD is known to be caused by degeneration of dopamine neurons in the substantia nigra but the cause of cell death is largely unknown. Mammalian neurokinins [NKs] are a group of neuropeptides that include substance P (SP; neurokinin-1, NK-1), substance K (SK; NK-2; neurokinin A), and neuromedin K (NK; NK-3; neurokinin B). Their biological effects as neurotransmitters, neuromodulators, or neurotrophic-like factors are mediated by three distinct neurokinin receptors, namely SP receptor (SPR: NK-1 receptor, NK-1R), SKR (NK-2R), and NKR (NK-3R). Several lines of evidence have indicated that neurokinins are implicated in the pathogenesis of PD. First, decreases of SP level and SP-immunoreactivity have been found in nigral and striatal tissues of animals with PD and postmortem PD patients. Second, NKs exert neuroprotective effects on neurons. In addition, NK receptors, namely NK-1 and NK-3 receptors, are abundantly localized in dopaminergic and cholinergic neurons of the basal ganglia, indicating that these neurons are under the physiological regulation of NKs. Moreover, modulation in motor activity occurred in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice, PD animal model, after systemic administration of NK receptor agonists. NKs and NK receptors, therefore, might be important molecules that are associated with functions and survival of neurons in the basal ganglia, in particular the dopamine neurons. Further studies should be devoted to elucidate the functional roles of NK systems in (a) the neuropathogenesis and neuroprotection during the course of PD, (b) the efficacy of NK receptor drugs towards PD, and (c) potential therapeutic intervention that targets at the prevention or treatment of PD.
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Affiliation(s)
- L W Chen
- Institute of Neurosciences, The Fourth Military Medical University, Xi'an 710032, P R China.
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41
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Chan WS, Yeung CW, Chung EKY, Lau WK, Chan YS, Yung KKL. Differential expression of alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate glutamate receptors in the rat striatum during postnatal development. Neurosignals 2004; 12:302-9. [PMID: 14739560 DOI: 10.1159/000075312] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [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: 04/02/2003] [Accepted: 06/11/2003] [Indexed: 11/19/2022] Open
Abstract
Alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA)-type glutamate receptors (GluR1-4) are one of the most important ionotropic glutamate receptors in the striatum, a key region of the basal ganglia. The present study investigated the trend of developmental expression of AMPA receptor subunits in the striatum of rats in different developmental stages, i.e., at postnatal day 7 (PND7), PND21 and adult. Perfuse-fixed striatal sections were used. The expression of AMPA subunits was studied by immunofluorescence and reverse transcriptase-polymerase chain reaction (RT-PCR). RT-PCR revealed that the levels of expression of the GluR1 and GluR3 mRNAs were the same among the age groups. The level of GluR2 mRNA was highest in PND21 rats and lowest in adult. The highest level of GluR4 mRNA was detected in rats at PND7. Similar trends of GluR1, GluR2 and GluR2/3 immunoreactivity expression were observed using commercially available specific antibodies. In addition, a large proportion of parvalbumin-immunoreactive GABAergic interneurons in the striatum were found to display GluR1 immunoreactivity in PND21 and adult rats. In contrast, most of the choline acetyltransferase-immunoreactive cholinergic interneurons were found to display GluR2 immunoreactivity but less GluR1 and no GluR2/3 immunoreactivity in PND21 and adult rats. The present study suggests that there is a distinct pattern of expression of AMPA-type receptor mRNAs and proteins in the rat striatum at different stages of development.
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Affiliation(s)
- W S Chan
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, PR China
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Mok NS, Priori SG, Napolitano C, Chan KK, Bloise R, Chan HW, Fung WH, Chan YS, Chan WK, Lam C, Chan NY, Tsang HH. Clinical profile and genetic basis of Brugada syndrome in the Chinese population. Hong Kong Med J 2004; 10:32-7. [PMID: 14967853] [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: 04/28/2023] Open
Abstract
OBJECTIVE To study the clinical profile and genetic basis of Brugada syndrome in Chinese patients. DESIGN Prospective observational study. SETTING Seven regional public hospitals, Hong Kong. MAIN OUTCOME MEASURES The clinical and follow-up data of 50 patients (47 men, 3 women; mean age, 53 years) were collected, and genetic data of 36 probands and eight family members of three genotyped probands were analysed. RESULTS Eight patients survived sudden cardiac death (group A), 12 had syncope of unknown origin but no sudden death (group B), and 30 were asymptomatic before recognition of Brugada syndrome (group C). Programmed electrical stimulation induced sustained ventricular arrhythmias in 88% (7/8), 82% (9/11), and 27% (3/11) of patients in group A, group B, and group C, respectively. New arrhythmic events occurred in 50% (4/8) of patients in group A and 17% (2/12) of patients in group B after a mean follow-up period of 30 (standard deviation, 13) months and 25 (7) months, respectively. All group C patients remained asymptomatic during a mean follow-up period of 25 (standard deviation, 11) months. Five of 36 probands and three of eight family members who underwent genetic testing were found to have a mutation in their SCN5A gene. CONCLUSIONS Chinese patients with Brugada syndrome who are symptomatic have a high likelihood of arrhythmia recurrence, whereas asymptomatic patients enjoy a good short-term prognosis. The prevalence of SCN5A mutation among probands is 14%. Thus, Chinese patients with Brugada syndrome share with their western counterparts similar clinical and genetic heterogeneity.
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Affiliation(s)
- N S Mok
- Department of Medicine and Geriatrics, Princess Margaret Hospital, Laichikok, Hong Kong.
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Chen LW, Hu HJ, Liu HL, Yung KKL, Chan YS. Identification of brain-derived neurotrophic factor in nestin-expressing astroglial cells in the neostriatum of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated mice. Neuroscience 2004; 126:941-53. [PMID: 15207328 DOI: 10.1016/j.neuroscience.2004.04.020] [Citation(s) in RCA: 24] [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] [Accepted: 04/08/2004] [Indexed: 02/02/2023]
Abstract
Up-regulation of nestin expression was significantly induced in the caudate-putamen of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice in our previous observation [Brain Res 925 (2002) 9]. We hypothesized that the nestin-expressing cells might play an important role in the pathogenesis of parkinsonian model, and characterization of these nestin-expressing cells was studied by RT-PCR, immunohistochemistry and semi-quantitative analysis for various markers of glial fibrillary acid protein (GFAP), S-100, neuronal nuclear specific protein (NeuN), beta-tubulin, Ki-67 and brain-derived neurotrophic factor (BDNF) expression in MPTP-treated C57/BL mice. Firstly, significant increasing in both nestin protein and mRNA was found in MPTP-treated mice. Up-regulation of nestin expression started at day 1, peaked at day 3, and gradually went down at days 7-21 in the neostriatum after MPTP treatment. Secondly, double immunofluorescence indicated that almost all of nestin-positive cells exhibited GFAP (98%) or S-100 (96%)-immunoreactivity, whereas NeuN or beta-tubulin was hardly detected in these nestin-positive cells. Thirdly, a minor population (7.0%) of nestin-positive cells showed Ki-67 (cell proliferation marker)-immunoreactivity, showing some of them went into cell mitotic state. Finally but more interestingly, a major population (86%) of nestin-expressing cells also exhibited immunoreactivity for BDNF, one neurotrophic factor. These results present time-dependent up-regulation of nestin expression in neostriatum, the proliferative and neurotrophic properties of nestin-expressing astroglial cells in MPTP-treated C57/BL mice. Taken together with previous observations, this study suggests that nestin-expressing activated astroglial cells, possibly partially through synthesizing and releasing neurotrophic factors such as BDNF in the basal ganglia, may play important roles in protection of nigrostriatal dopamine neurons and in the pathogenesis of Parkinson's disease in mammals.
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Affiliation(s)
- L-W Chen
- Institute of Neurosciences, The Fourth Military Medical University, Xi'an 710032, PR People's Republic of China.
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Lai SK, Tse YC, Yang MS, Wong CKC, Chan YS, Yung KKL. Gene expression of glutamate receptors GluR1 and NR1 is differentially modulated in striatal neurons in rats after 6-hydroxydopamine lesion. Neurochem Int 2003; 43:639-53. [PMID: 12892651 DOI: 10.1016/s0197-0186(03)00080-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [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: 10/27/2022]
Abstract
In the present study, we attempted to address the modulation of the gene expression of N-methyl-D-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA) glutamate receptors in the neostriatum of the 6-hydroxydopamine (6-OHDA)-lesioned rat, an animal model of Parkinson's disease. After 2 weeks of lesion, reverse transcriptase-polymerase chain reactions (RT-PCRs) revealed significant reduction in GluR1 mRNA expression but a significant enhancement of NR1 mRNA expression in the striatal tissues of the lesioned side. No modulation in the mRNA expression of GluR2, GluR3, GluR4 and NR2B were found. Immunofluorescence with digital imaging analysis also demonstrated a significant reduction in GluR1 immunoreactivity in the lesioned neostriatum. Interestingly, the reduction in GluR1 immunoreactivity was primarily observed in presumed striatal medium spiny neurons but not in parvalbumin-labeled striatal GABAergic interneurons. Immunoreactivity for GluR2, GluR2/3, GluR4, NR1 and NR2B was unchanged in neurons of the neostriatum of the lesioned side. The present results indicate that there is an opposite trend in modulation in the gene expressions of GluR1 and NR1 in the neostriatum of 6-OHDA-lesioned rats after dopamine denervation. Modulation of GluR1 mRNA and immunoreactivity is likely to be limited in the striatal projection neurons. These findings have implications for the use of NMDA and AMPA receptor antagonists in the treatment of Parkinson's disease.
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Affiliation(s)
- S K Lai
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong, PR China
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Lui PW, Suen KC, Chan YS, Yung WH, Yung KKL. Striatal neurons but not nigral dopaminergic neurons in neonatal primary cell culture express endogenous functional N-methyl-d-aspartate receptors. ACTA ACUST UNITED AC 2003; 120:9-21. [PMID: 14667572 DOI: 10.1016/j.molbrainres.2003.09.015] [Citation(s) in RCA: 6] [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: 01/08/2023]
Abstract
Developmental expression of N-methyl-D-aspartate (NMDA) receptor subunits were determined and compared in striatal and nigral neurons in neonatal primary cell cultures. In striatal neurons, NR1, NR2A and NR2B mRNAs and immunoreactivity, and NR2D mRNA were found and the maximal levels of NR1 mRNA and immunoreactivity expression were found at 6 day-in-vitro (DIV). NMDA receptors found at this stage in striatal neurons are likely to contain NR1 plus NR2A, NR2B and NR2D subunits. In nigral neurons, NR1 and NR2B mRNAs and immunoreactivity, and NR2D mRNA were found and the maximal level of NR1 immunoreactivity expression was found at 10 DIV. Unlike striatal neurons, NMDA receptors found in nigral neurons are likely to contain NR1 plus NR2B and NR2D subunits only. NMDA-induced toxicity assays showed that striatal neurons were most susceptible to cell death at around 10 DIV but nigral neurons were not susceptible to NMDA-induced cell death at all stages. In addition, patch clamp analysis revealed that functional NMDA receptors could only be found in striatal neurons but not in nigral dopaminergic neurons in vitro. The present results indicate that striatal and nigral neurons are programmed to express distinct NMDA receptor subunits during their endogenous development in cell cultures. Despite dopaminergic neurons in culture display NMDA receptor subunits, functional NMDA receptors are not assembled. The present findings have demonstrated that dopaminergic neurons in vitro may behave very differently to their counterparts in vivo in terms of NMDA receptor-mediated responses. Our results also have implications in transplantations using dopaminergic neurons in vitro in treatments of Parkinson's disease.
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Affiliation(s)
- P W Lui
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong, PR China
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Chau CH, Shum DKY, Li H, Pei J, Lui YY, Wirthlin L, Chan YS, Xu XM. Chondroitinase ABC enhances axonal regrowth through Schwann cell-seeded guidance channels after spinal cord injury. FASEB J 2003; 18:194-6. [PMID: 14630702 DOI: 10.1096/fj.03-0196fje] [Citation(s) in RCA: 147] [Impact Index Per Article: 7.0] [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: 11/11/2022]
Abstract
Grafting of Schwann cell-seeded channels into hemisected adult rat thoracic spinal cords has been tested as a strategy to bridge the injured cord. Despite success in guiding axonal growth into the graft, regeneration across the distal graft-host interface into the host spinal cord was limited. We hypothesized that chondroitin sulfate (CS) glycoforms deposited at the gliotic front of the interface constitute a molecular barrier to axonal growth into the host cord. Because CS glycoforms deposited by purified astrocytes in vitro were removable by digestion with chondroitinase ABC, we attempted to achieve likewise by infusion of the enzyme to the host side of the interface. By 1 month post-treatment, significant numbers of regenerating axons crossed an interface that was subdued in macrophage/microglia reaction and decreased in CS-immunopositivity. The axons extended as far into the caudal cord as 5 mm, in contrast to nil in vehicle-infused controls. Fascicular organizations of axon-Schwann cell units within the regenerated tissue cable were better-preserved in enzyme-treated cords than in vehicle-infused controls. We conclude that CS glycoforms deposited during gliosis at the distal graft-host interface could be cleared by the in vivo action of chondroitinase ABC to improve prospects of axonal regeneration into the host spinal cord.
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Affiliation(s)
- C H Chau
- Department of Biochemistry, Faculty of Medicine, University of Hong Kong, Hong Kong, China
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Chan YS, Chen LW, Lai CH, Shum DKY, Yung KKL, Zhang FX. Receptors of glutamate and neurotrophin in vestibular neuronal functions. J Biomed Sci 2003; 10:577-87. [PMID: 14576459 DOI: 10.1159/000073522] [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: 11/19/2022] Open
Abstract
The last decade has witnessed advances in understanding the roles of receptors of neurotrophin and glutamate in the vestibular system. In the first section of this review, the biological actions of neurotrophins and their receptors in the peripheral and central vestibular systems are summarized. Emphasis will be placed on the roles of neurotrophins in developmental plasticity and in the maintenance of vestibular function in the adult animal. This is reviewed in relation to the developmental expression pattern of neurotrophins and their receptors within the vestibular nuclei. The second part is focused on the functional role of different glutamate receptors on central vestibular neurons. The developmental expression pattern of glutamate receptor subunits within the vestibular nuclei is reviewed in relation to the potential role of glutamate receptors in regulating the development of vestibular function.
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Affiliation(s)
- Y S Chan
- Department of Physiology, Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
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48
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Abstract
By using a double immunofluorescence, we have examined the distribution of striatal GABAergic neurons that expressed substance P receptor (SPR) in the basal ganglia of adult C57 mice. The distribution of GABA-immunoreactive neurons completely or partially overlapped with that of SPR-immunoreactive neurons in the striatum (i.e. the caudate-putamen), globus pallidus, ventral pallidum, and nucleus accumbens. Neurons showing both GABA- and SPR-immunoreactivities were, however, predominantly found in the caudate-putamen, and most of them were characterized by their large-sized aspiny neuronal profile. Semi-quantification indicated that only about 13% of the total GABA-immunoreactive neurons (including large and medium-sized) displayed SPR-immunoreactivity, and these double-labeled neurons constituted about 31% of the total SPR-immunoreactive cells in the striatum. Neurons double-labeled with GABA- and SPR-immunoreactivities were hardly detected in other aforementioned regions of the basal ganglia. In addition, double immunofluorescence also showed co-localization of SPR- with glutamic acid decarboxylase-immunoreactivity, but not with parvalbumin-immunoreactivity, in the striatal neurons. Taken together with previous reports, the present study has suggested that a sub-population of striatal GABA-ergic neurons, most possibly GABA-ergic interneurons, may also receive direct physiological modulation by tachykinins through SPR in the basal ganglia of mammals.
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Affiliation(s)
- L-W Chen
- Institute of Neurosciences, Fourth Military Medical University, 710032, Xi'an, China.
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49
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Lau WK, Lui PW, Wong CKC, Chan YS, Yung KKL. Differential expression of N-methyl-D-aspartate receptor subunit messenger ribonucleic acids and immunoreactivity in the rat neostriatum during postnatal development. Neurochem Int 2003; 43:47-65. [PMID: 12605882 DOI: 10.1016/s0197-0186(02)00191-2] [Citation(s) in RCA: 22] [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: 12/21/2022]
Abstract
The present study was performed to investigate the patterns of gene expression of N-methyl-D-aspartate (NMDA) receptors (NRs) in the rat neostriatum during postnatal development. Reverse transcriptase-polymerase chain reactions (RT-PCR) indicated that levels of NR1, NR2A and NR2D mRNAs reached peak levels between postnatal days 7 (PND 7) and PND 14. The levels of NR2B and NR2C mRNAs were low at PND 1 and their levels increased at PND 7 and remained high in adults. Immunofluorescence combined with image analysis revealed that the levels of NR1 immunoreactivity rose to its maximum at PND 14. In contrast, NR1 immunoreactivity rose progressively in perikarya of striatal neurons. Levels of NR2A immunoreactivity in the neostriatum were highest in adults. However, levels of NR2A immunoreactivity were higher in striatal neurons at PND 1 and PND 7. Levels of NR2B immunoreactivity were highest at PND 7. In the perikarya of striatal neurons however, the highest levels of NR2B immunoreactivity were detected at PND 14 and adult striatal neurons. In addition, double immunofluorescence revealed that the levels of NR1 immunoreactivity increased but the levels of NR2A immunoreactivity were the same in parvalbumin (PV)-positive striatal interneurons of PND 14 and adult rats. NR2B immunoreactivity was not detected in PV-positive neurons of PND 14 rats, but intense NR2B labeling was seen in PV-positive neurons of adult rats. Last but not least, in choline acetyltransferase (ChAT)-positive striatal interneurons of PND 14 and adult rats, levels of NR1 and NR2A immunoreactivity was seen to increase. Level of NR2B immunoreactivity remained the same in ChAT-positive neurons of PND 14 and adult rats. The present results indicate that there are differential patterns of expression of NR mRNAs and immunoreactivity in the neostriatum during different stages of postnatal development. Different combinations of NR have been found in different subpopulations of striatal neurons at different developmental stages. NR1, NR2A and NR2B are the major NMDA receptor subunits expressed during development. The change in patterns of expression of NR may be related to the functional maturation of neurons in the neostriatum.
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Affiliation(s)
- W K Lau
- Department of Biology, Hong Kong Baptist University, 224 Waterloo Road, Kowloon Tong, Hong Kong, PR China
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Abstract
The distribution of high-affinity neurotrophin receptors in cells of the vestibular nuclear complex and its subnuclei of adult rats was examined. We noted a high density of tyrosine kinase (Trk) A- and B- and a lower density of TrkC-immunostained cells. In particular, long, intensely labelled immunostained-TrkB fibres formed networks in the neuropil. Both TrkA- and TrkB-immunostained cells were widely distributed in the lateral, medial and spinal vestibular nuclei, and were less frequently seen in the superior vestibular nucleus, x and y subnuclei. However, immunostaining for TrkC was weak in many cells within the vestibular nuclei. The widespread and abundant neuronal distribution of Trk receptors predicts that their associated neurotrophins exert significant effects on individual cells within the vestibular nuclei.
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Affiliation(s)
- F X Zhang
- Department of Physiology, The University of Hong Kong, Hong Kong, P.R. China
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