Displaying publications 61 - 80 of 99 in total

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  1. Reginald K, Tan CL, Chen S, Yuen L, Goh SY, Chew FT
    Sci Rep, 2018 08 06;8(1):11743.
    PMID: 30082894 DOI: 10.1038/s41598-018-30224-z
    We previously identified an expressed sequence tag clone, Der f 22, showing 41% amino acid identity to published Der f 2, and show that both genes are possible paralogues. The objective of this study was to characterize the genomic, proteomic and immunological functions Der f 22 and Der f 2. The full-length sequence of Der f 2 and Der f 22 coded for mature proteins of 129 and 135 amino acids respectively, both containing 6 cysteine residues. Phylogenetic analysis of known group 2 allergens and their homologues from our expressed sequence tag library showed that Der f 22 is a paralogue of Der f 2. Both Der f 2 and Der f 22 were single gene products with one intron. Both allergens showed specific IgE-binding to over 40% of the atopic patients, with limited of cross-reactivity. Both allergens were detected at the gut region of D. farinae by immunostaining. Der f 22 is an important allergen with significant IgE reactivity among the atopic population, and should be considered in the diagnostic panel and evaluated as future hypoallergen vaccine therapeutic target.
  2. Lai CM, Mak KK, Watanabe H, Jeong J, Kim D, Bahar N, et al.
    Public Health, 2015 Sep;129(9):1224-36.
    PMID: 26343546 DOI: 10.1016/j.puhe.2015.07.031
    OBJECTIVES: This study examines the associations of Internet addiction with social anxiety, depression, and psychosocial well-being among Asian adolescents. A self-medication model conceptualizing Internet addiction as a mediating role in relating depression and social anxiety to negative psychosocial well-being was tested.
    STUDY DESIGN: A cross-sectional survey.
    METHODS: In the Asian Adolescent Risk Behavior Survey (AARBS), 5366 adolescents aged 12-18 years from six Asian countries (China, Hong Kong, Japan, South Korea, Malaysia, and Philippines) completed a questionnaire with items of the Internet Addiction Test (IAT), Social Anxiety Scale for Adolescents (SAS-A), Center for Epidemiological Studies Depression Scale (CESD), Self-Rated Health of the Nation Outcome Scales for Children and Adolescents (HoNOSCA-SR) in the 2012-2013 school year. Structural equation modelling was used to examine the mediating role of Internet addiction in depression, social anxiety, and subjective psychosocial well-being.
    RESULTS: Significant differences on the scores of IAT, SAS-A, CESD, and HoNOSCA-SR across the six countries were found. The proposed self-medication model of Internet addiction received satisfactory goodness-of-fit with data of all countries. After the path from social anxiety to Internet addiction had been discarded in the revised model, there was a significant improvement of the goodness-of-fit in the models for Japan, South Korea, and the Philippines.
    CONCLUSIONS: Depression and social anxiety reciprocally influenced, whereas depression associated with poorer psychosocial well-being directly and indirectly through Internet addiction in all six countries. Internet addiction mediated the association between social anxiety and poor psychosocial well-being in China, Hong Kong, and Malaysia.
    KEYWORDS: Adolescents; Asian; Depression; Internet addiction; Social anxiety; Structural equation modelling
  3. Zhang W, Jiang B, Zeng M, Duan Y, Wu Z, Wu Y, et al.
    J Virol, 2020 04 16;94(9).
    PMID: 32075929 DOI: 10.1128/JVI.01850-19
    Duck Tembusu virus (DTMUV), which is similar to other mosquito-borne flaviviruses that replicate well in most mammalian cells, is an emerging pathogenic flavivirus that has caused epidemics in egg-laying and breeding waterfowl. Immune organ defects and neurological dysfunction are the main clinical symptoms of DTMUV infection. Preinfection with DTMUV makes the virus impervious to later interferon (IFN) treatment, revealing that DTMUV has evolved some strategies to defend against host IFN-dependent antiviral responses. Immune inhibition was further confirmed by screening for DTMUV-encoded proteins, which suggested that NS2A significantly inhibited IFN-β and IFN-stimulated response element (ISRE) promoter activity in a dose-dependent manner and facilitated reinfection with duck plague virus (DPV). DTMUV NS2A was able to inhibit duck retinoic acid-inducible gene-I (RIG-I)-, and melanoma differentiation-associated gene 5 (MDA5)-, mitochondrial-localized adaptor molecules (MAVS)-, stimulator of interferon genes (STING)-, and TANK-binding kinase 1 (TBK1)-induced IFN-β transcription, but not duck TBK1- and interferon regulatory factor 7 (IRF7)-mediated effective phases of IFN response. Furthermore, we found that NS2A competed with duTBK1 in binding to duck STING (duSTING), impaired duSTING-duSTING binding, and reduced duTBK1 phosphorylation, leading to the subsequent inhibition of IFN production. Importantly, we first identified that the W164A, Y167A, and S361A mutations in duSTING significantly impaired the NS2A-duSTING interaction, which is important for NS2A-induced IFN-β inhibition. Hence, our data demonstrated that DTMUV NS2A disrupts duSTING-dependent antiviral cellular defenses by binding with duSTING, which provides a novel mechanism by which DTMUV subverts host innate immune responses. The potential interaction sites between NS2A and duSTING may be the targets of future novel antiviral therapies and vaccine development.IMPORTANCE Flavivirus infections are transmitted through mosquitos or ticks and lead to significant morbidity and mortality worldwide with a spectrum of manifestations. Infection with an emerging flavivirus, DTMUV, manifests with clinical symptoms that include lesions of the immune organs and neurological dysfunction, leading to heavy egg drop and causing serious harm to the duck industry in China, Thailand, Malaysia, and other Southeast Asian countries. Mosquito cells, bird cells, and mammalian cell lines are all susceptible to DTMUV infection. An in vivo study revealed that BALB/c mice and Kunming mice were susceptible to DTMUV after intracerebral inoculation. Moreover, there are no reports about DTMUV-related human disease, but antibodies against DTMUV and viral RNA were detected in serum samples of duck industry workers. This information implies that DTMUV has expanded its host range and may pose a threat to mammalian health. However, the pathogenesis of DTMUV is largely unclear. Our results show that NS2A strongly blocks the STING-induced signal transduction cascade by binding with STING, which subsequently blocks STING-STING binding and TBK1 phosphorylation. More importantly, the W164, Y167, or S361 residues in duSTING were identified as important interaction sites between STING and NS2A that are vital for NS2A-induced IFN production and effective phases of IFN response. Uncovering the mechanism by which DTMUV NS2A inhibits IFN in the cells of its natural hosts, ducks, will help us understand the role of NS2A in DTMUV pathogenicity.
  4. Zhang W, Chen S, Mahalingam S, Wang M, Cheng A
    J Gen Virol, 2017 Oct;98(10):2413-2420.
    PMID: 28874226 DOI: 10.1099/jgv.0.000908
    Tembusu virus (TMUV, genus Flavivirus, family Flaviviridae) was first isolated in 1955 from Culex tritaeniorhynchus mosquitoes in Kuala Lumpur, Malaysia. In April 2010, duck TMUV was first identified as the causative agent of egg-drop syndrome, characterized by a substantial decrease in egg laying and depression, growth retardation and neurological signs or death in infected egg-laying and breeder ducks, in the People's Republic of China. Since 2010, duck TMUV has spread to most of the duck-producing regions in China, including many of the coastal provinces, neighbouring regions and certain Southeast Asia areas (i.e. Thailand and Malaysia). This review describes the current understanding of the genome characteristics, host range, transmission, epidemiology, phylogenetic and immune evasion of avian-origin TMUV and the innate immune response of the host.
  5. Chen ST
    Med J Malaysia, 1985 Jun;40(2):90-4.
    PMID: 3834291
    Percentile head circumference charts, from six to eleven years of age, for boys and girls are presented. These can be used to monitor the head circumference of Malaysian children.
  6. Chen ST
    Med J Malaysia, 1985 Jun;40(2):80-9.
    PMID: 3834290
    Percentile growth charts of weight, length and head circumference, from birth to six years of age, for boys and girls, are presented. These can be used to monitor the growth of Malaysian children.
  7. Chen ST
    J Trop Med Hyg, 1989 Dec;92(6):386-90.
    PMID: 2607571
    The infant immunization coverage for triple antigen (DPT) from 1968 and trivalent oral polio vaccine (TOPV) from 1972 to 1985 for Peninsular Malaysia are presented. It shows that immunization coverage improved when the recommended age for first dose of DPT was changed from the fourth to the second month of life in 1972 and declined when the recommended age for the first dose of DPT and TOPV was revised again from the second to the third month of life in 1980. The advantages of immunizing children early in life are discussed.
  8. Chen ST
    J Singapore Paediatr Soc, 1989;31(3-4):178-85.
    PMID: 2638722
    126 Malay children from higher income families were followed-up regularly from birth to six years of age in the University Hospital, Kuala Lumpur. Their developmental performance was compared to that of Denver children. Generally, Malaysian and Denver children appear to be similar in their development during the first six years of life except for some minor differences in the personal-social, language and gross motor sectors. Malaysians appear to be slower in self-care but more advanced in "helping around the house", "playing interactive games" and in "separating from mother". They were slightly slower in gross motor function during the first year of life but more advanced during the second year of life. However, they were slightly more advanced in language development. The differences in development between the two groups of children are discussed and it is concluded that the differences can partly be explained by differences in socio-economic or cultural differences between the two groups of children. However, the influence of genetic factors cannot be dismissed.
  9. Chen ST
    Asia Pac J Public Health, 1989;3(1):19-25.
    PMID: 2497765 DOI: 10.1177/101053958900300104
    From the start of the school milk feeding programme in February 1985 to October 1986, a total of 2,766 children aged six to nine years from 12 primary schools in Ulu Selangor were followed-up for about two years. The children's weight and height were monitored at the beginning, in the middle and at the end of the study. The study shows that there is a reduction in the prevalence of protein-energy malnutrition in terms of underweight (15.3% to 8.6%), stunting (16.3% to 8.3%) and wasting (2.6% to 1.7%) from the start of the school feeding programme to two years later. Associated with this there was an improvement in the attendance rate of the children during the same period. As there was no major developmental change in Ulu Selangor during that period, it is likely that the reduction in the prevalence of protein-energy malnutrition and the improvement of the attendance rate among the children are due to the impact of the school milk feeding programme.
  10. Chen ST
    J Singapore Paediatr Soc, 1990;32(3-4):65-80.
    PMID: 2133760
    126 Malaysian children, 65 boys and 61 girls from higher income families were followed-up regularly from birth to six years of age in the University Hospital, Kuala Lumpur. Their physical growth, development, dietary and illness patterns were measured at each visit. The study confirms the observations of previous studies that boys are, on the average, heavier and taller than girls and that Asians are smaller in size with relatively shorter legs compared with children of European ancestry. These racial differences are due to a combination of genetic and environmental differences. Since there are genetic differences in the size and shape of children, standards applicable to the specific population should be used to obtain the best results when assessing the health of an individual child. The growth charts presented in this paper can be used as standards to monitor the growth of Asian infants and pre-school children.
  11. Chen ST
    J Singapore Paediatr Soc, 1990;32(3-4):102-7.
    PMID: 2133745
    Over the past hundred years in industrialised countries and recently in some developing countries, children have been getting larger and growing to maturity more rapidly. This paper compares the growth of Malaysian children with similar socioeconomic backgrounds but born about twelve years apart. Data were obtained from records of 227 children born between 1968 and 1973 and 238 children born between 1980 and 1985. The children were followed-up regularly at the University Hospital Child Health Clinic in Kuala Lumpur for a variable period from birth to five years of age. Measurements for their weight, length and head circumference were taken at each visit. There is a directional indication that boys and girls of the 1980-1985 cohort are taller, heavier and have bigger head circumferences from birth to five years of age and the difference widens as the child grows older. This study clearly shows that a positive secular trend has taken place in the last decade, reflecting an improvement of living conditions with time. The factors involved in the positive secular trend are manifold and the most important is probably nutrition.
  12. Chen ST
    J Singapore Paediatr Soc, 1990;32(3-4):87-96.
    PMID: 2133762
    126 Malaysian children, 65 boys and 61 girls from higher income families were followed-up regularly from birth to six years of age in the University Hospital, Kuala Lumpur. The study shows that for boys and girls, there is a progressive increase in the left mid-upper arm circumference from birth to six years of age. However the rate of growth is not even, being most rapid during the first four month of infancy, then rapidly decreases during the middle third of infancy and thereafter it decreases slowly and by the second year of life, there is hardly any increase in the arm circumference. The left triceps skinfold thickness curves for boys and girls rise rapidly after birth to reach a peak at about three to five months before commencing to decline and then flatten off from the second year of life. The study also shows that on the whole, boys have slightly bigger arm circumference than girls during the first two years of life. From two years of age, girls on the average have more fat than boys. However this difference is statistically not significant at the ages tested. This paper also presents the left mid-upper arm circumference and left triceps skinfold percentile charts of Malaysian boys and girls from birth to six years of age.
  13. Chen ST
    J Singapore Paediatr Soc, 1990;32(3-4):81-6.
    PMID: 2133761
    126 Malaysian children, 65 boys and 61 girls from higher income families were followed-up regularly from birth to six years of age in the University Hospital, Kuala Lumpur. The study confirms the observations of previous studies that growth velocity of head circumference is most rapid during the first few months of infancy and then decreases so that by the fifth year of life the increment is minimal. It also confirms the fact that boys have bigger head circumferences than girls. The paper also presents the head circumference distance and velocity percentile charts which can be used to monitor the head circumference of Malaysian children.
  14. Dugdale AE, Chen ST
    Arch Dis Child, 1979 Nov;54(11):880-5.
    PMID: 393181
    The draw-a-man (DAM) and draw-a-woman (DAW) tests were given to 307 schoolchildren in Petaling Jaya, Malaysia. The children were ethnically Malay, Chinese, or Indian (Tamil), and all came from lower socioeconomic groups. The standard scores of the Chinese children averaged 118 in the DAM and 112 in the DAW tests. These scores were significantly better than the American standards. Malay children scored significantly lower than Chinese, and Tamil children scored lower again. The nutritional status of the children had no influence on the scores. Chinese and Tamil children scored better in the DAM than the DAW, while in Malay boys the reverse was true. Malay children tended to emphasise clothing in the DAM, but Chinese and Tamil children scored better on items relating to facial features and body proportions. The Goodenough-Harris draw-a-person tests are obviously not culture-free, but the causes of ethnic differences have not been elucidated.
  15. Chen ST
    Trop Geogr Med, 1975 Mar;27(1):103-8.
    PMID: 806152
    Pneumonia and diarrhoeas are an important cause of toddler mortality and morbidity in developing countries. Of the 147 children admitted to the University Hospital at Kuala Lumpur in 1971 for pneumonia and diarrhoeas 50 (34%) were found to be suffering from protein-calorie malnutrition of varying degrees of severity. The malnourished children tended to come from poorer homes, and to have a larger number of siblings born in rapid succession when compared with normal weight children. Anemia was more common among the malnourished children. The interaction of infection and malnutrition and the social implications of these diseases are important. It is vital that hospitals in developing countries promote health in addition to their traditional curative role.
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