Displaying publications 1 - 20 of 62 in total

  1. Chung KF, Seiffert J, Chen S, Theodorou IG, Goode AE, Leo BF, et al.
    ACS Nano, 2017 03 28;11(3):2652-2664.
    PMID: 28221763 DOI: 10.1021/acsnano.6b07313
    There is a potential for silver nanowires (AgNWs) to be inhaled, but there is little information on their health effects and their chemical transformation inside the lungs in vivo. We studied the effects of short (S-AgNWs; 1.5 μm) and long (L-AgNWs; 10 μm) nanowires instilled into the lungs of Sprague-Dawley rats. S- and L-AgNWs were phagocytosed and degraded by macrophages; there was no frustrated phagocytosis. Interestingly, both AgNWs were internalized in alveolar epithelial cells, with precipitation of Ag2S on their surface as secondary Ag2S nanoparticles. Quantitative serial block face three-dimensional scanning electron microscopy showed a small, but significant, reduction of NW lengths inside alveolar epithelial cells. AgNWs were also present in the lung subpleural space where L-AgNWs exposure resulted in more Ag+ve macrophages situated within the pleura and subpleural alveoli, compared with the S-AgNWs exposure. For both AgNWs, there was lung inflammation at day 1, disappearing by day 21, but in bronchoalveolar lavage fluid (BALF), L-AgNWs caused a delayed neutrophilic and macrophagic inflammation, while S-AgNWs caused only acute transient neutrophilia. Surfactant protein D (SP-D) levels in BALF increased after S- and L-AgNWs exposure at day 7. L-AgNWs induced MIP-1α and S-AgNWs induced IL-18 at day 1. Large airway bronchial responsiveness to acetylcholine increased following L-AgNWs, but not S-AgNWs, exposure. The attenuated response to AgNW instillation may be due to silver inactivation after precipitation of Ag2S with limited dissolution. Our findings have important consequences for the safety of silver-based technologies to human health.
  2. 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.
  3. Yong SC, Chen SJ, Boo NY
    Arch. Dis. Child. Fetal Neonatal Ed., 2005 Nov;90(6):F480-3.
    PMID: 15941825
    To compare the incidence of nasal trauma associated with the use of prong or mask during nasal continuous positive airway pressure (nCPAP) support in very low birthweight (<1501 g) infants.
  4. 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.
  5. Chen ST, Domala Z
    Asia Pac J Public Health, 1989;3(4):274-7.
    PMID: 2638907 DOI: 10.1177/101053958900300405
    1,256 malnourished children, aged seven to ten years, were selected for study, 575 from Kuala Langat, 416 from Wilayah Persekutuan and 265 from Ulu Selangor. Ninety-three percent of the children were from low socioeconomic groups with large family size, and most of their parents had only primary or no formal education. During the study period, children in Kuala Langat received daily milk supplementation for five days per week, those in Wilayah Persekutuan for two days per week, while those in Ulu Selangor did not receive any milk supplementation. The study shows that a majority of the malnourished primary school children liked to drink milk and that milk intolerance was not a problem among them.
  6. Klionsky DJ, Abdelmohsen K, Abe A, Abedin MJ, Abeliovich H, Acevedo Arozena A, et al.
    Autophagy, 2016;12(1):1-222.
    PMID: 26799652 DOI: 10.1080/15548627.2015.1100356
  7. Rebbeck TR, Friebel TM, Mitra N, Wan F, Chen S, Andrulis IL, et al.
    Breast Cancer Res., 2016 11 11;18(1):112.
    PMID: 27836010
    BACKGROUND: Most BRCA1 or BRCA2 mutation carriers have inherited a single (heterozygous) mutation. Transheterozygotes (TH) who have inherited deleterious mutations in both BRCA1 and BRCA2 are rare, and the consequences of transheterozygosity are poorly understood.

    METHODS: From 32,295 female BRCA1/2 mutation carriers, we identified 93 TH (0.3 %). "Cases" were defined as TH, and "controls" were single mutations at BRCA1 (SH1) or BRCA2 (SH2). Matched SH1 "controls" carried a BRCA1 mutation found in the TH "case". Matched SH2 "controls" carried a BRCA2 mutation found in the TH "case". After matching the TH carriers with SH1 or SH2, 91 TH were matched to 9316 SH1, and 89 TH were matched to 3370 SH2.

    RESULTS: The majority of TH (45.2 %) involved the three common Jewish mutations. TH were more likely than SH1 and SH2 women to have been ever diagnosed with breast cancer (BC; p = 0.002). TH were more likely to be diagnosed with ovarian cancer (OC) than SH2 (p = 0.017), but not SH1. Age at BC diagnosis was the same in TH vs. SH1 (p = 0.231), but was on average 4.5 years younger in TH than in SH2 (p 

  8. Chen ST, Edsall G, Peel MM, Sinnathuray TA
    Bull. World Health Organ., 1983;61(1):159-65.
    PMID: 6601539
    The relationship between the timing of maternal tetanus toxoid immunization and the presence of protective antitoxin in placental cord blood was investigated among women admitted to the obstetrical service of the University Hospital in Kuala Lumpur, Malaysia. The 1st dose was given between 13-39 weeks of gestation, with a median of 29 weeks. The 2nd dose was given an average of 4 weeks later. Protection was conferred on 80% or more of newborns whose mothers received their 1st tetanus toxoid injection 60 days or more before delivery. Protective levels were seen in all cord blood samples from infants whose mothers had received their 1st injection 90 days before delivery. Similarly,protective titers were found in 100% of cord blood samples when the 2nd maternal injection was give 60 days or more before delivery. There was no significant degree of protection when immunization was carried out less than 20 days before delivery. A single-dose schedule provided no protection when less than 70 days before delivery. Cord and maternal antiotoxin titers differed by no more than 1 2-fold dilution for almost all of the individual paired sera. A cord: maternal antitoxin ratio of 2 was more likely to occur with increasing time between the 2nd injection and delivery. Overall, these findings indicate that the 1st injection of a 2-dose maternal tetanus toxoid schedule should be given at least 60 days and preferably 90 days before delivery.
  9. Sweeney S, Leo BF, Chen S, Abraham-Thomas N, Thorley AJ, Gow A, et al.
    Colloids Surf B Biointerfaces, 2016 Sep 01;145:167-75.
    PMID: 27182651 DOI: 10.1016/j.colsurfb.2016.04.040
    Accompanying increased commercial applications and production of silver nanomaterials is an increased probability of human exposure, with inhalation a key route. Nanomaterials that deposit in the pulmonary alveolar region following inhalation will interact firstly with pulmonary surfactant before they interact with the alveolar epithelium. It is therefore critical to understand the effects of human pulmonary surfactant when evaluating the inhalation toxicity of silver nanoparticles. In this study, we evaluated the toxicity of AgNPs on human alveolar type-I-like epithelial (TT1) cells in the absence and presence of Curosurf(®) (a natural pulmonary surfactant substitute), hypothesising that the pulmonary surfactant would act to modify toxicity. We demonstrated that 20nm citrate-capped AgNPs induce toxicity in human alveolar type I-like epithelial cells and, in agreement with our hypothesis, that pulmonary surfactant acts to mitigate this toxicity, possibly through reducing AgNP dissolution into cytotoxic Ag(+) ions. For example, IL-6 and IL-8 release by TT1 cells significantly increased 10.7- and 35-fold, respectively (P<0.01), 24h after treatment with 25μg/ml AgNPs. In contrast, following pre-incubation of AgNPs with Curosurf(®), this effect was almost completely abolished. We further determined that the mechanism of this toxicity is likely associated with Ag(+) ion release and lysosomal disruption, but not with increased reactive oxygen species generation. This study provides a critical understanding of the toxicity of AgNPs in target human alveolar type-I-like epithelial cells and the role of pulmonary surfactant in mitigating this toxicity. The observations reported have important implications for the manufacture and application of AgNPs, in particular for applications involving use of aerosolised AgNPs.
  10. Shang X, Peng Z, Ye Y, Asan, Zhang X, Chen Y, et al.
    EBioMedicine, 2017 Sep;23:150-159.
    PMID: 28865746 DOI: 10.1016/j.ebiom.2017.08.015
    Hemoglobinopathies are among the most common autosomal-recessive disorders worldwide. A comprehensive next-generation sequencing (NGS) test would greatly facilitate screening and diagnosis of these disorders. An NGS panel targeting the coding regions of hemoglobin genes and four modifier genes was designed. We validated the assay by using 2522 subjects affected with hemoglobinopathies and applied it to carrier testing in a cohort of 10,111 couples who were also screened through traditional methods. In the clinical genotyping analysis of 1182 β-thalassemia subjects, we identified a group of additional variants that can be used for accurate diagnosis. In the molecular screening analysis of the 10,111 couples, we detected 4180 individuals in total who carried 4840 mutant alleles, and identified 186 couples at risk of having affected offspring. 12.1% of the pathogenic or likely pathogenic variants identified by our NGS assay, which were undetectable by traditional methods. Compared with the traditional methods, our assay identified an additional at-risk 35 couples. We describe a comprehensive NGS-based test that offers advantages over the traditional screening/molecular testing methods. To our knowledge, this is among the first large-scale population study to systematically evaluate the application of an NGS technique in carrier screening and molecular diagnosis of hemoglobinopathies.
  11. Sun Y, Wu G, Cheng KS, Chen A, Neoh KH, Chen S, et al.
    EBioMedicine, 2019 Aug;46:133-149.
    PMID: 31375425 DOI: 10.1016/j.ebiom.2019.07.044
    BACKGROUND: The evaluation for surgical resectability of pancreatic ductal adenocarcinoma (PDAC) patients is not only imaging-based but highly subjective. An objective method is urgently needed. We report on the clinical value of a phenotypic circulating tumor cell (CTC)-based blood test for a preoperative prognostic assessment of tumor metastasis and overall survival (OS) of PDAC patients.

    METHODS: Venous blood samples from 46 pathologically confirmed PDAC patients were collected prospectively before surgery and immunoassayed using a specially designed TU-chip™. Captured CTCs were differentiated into epithelial (E), mesenchymal and hybrid (H) phenotypes. A further 45 non-neoplastic healthy donors provided blood for cell line validation study and CTC false positive quantification.

    FINDINGS: A validated multivariable model consisting of disjunctively combined CTC phenotypes: "H-CTC≥15.0 CTCs/2ml OR E-CTC≥11.0 CTCs/2ml" generated an optimal prediction of metastasis with a sensitivity of 1.000 (95% CI 0.889-1.000) and specificity of 0.886 (95% CI 0.765-0.972). The adjusted Kaplan-Meier median OS constructed using Cox proportional-hazard models and stratified for E-CTC 

  12. Kim J, Hwang Y, Yoo M, Chen S, Lee IM
    Environ Sci Pollut Res Int, 2017 Nov;24(32):25137-25145.
    PMID: 28924945 DOI: 10.1007/s11356-017-0152-6
    In this study, the chemical substance flow of hydrogen fluoride (hydrofluoric acid, HF) in domestic chemical industries in 2014 was analyzed in order to provide a basic material and information for the establishment of organized management system to ensure safety during HF applications. A total of 44,751 tons of HF was made by four domestic companies (in 2014); import amount was 95,984 tons in 2014 while 21,579 tons of HF was imported in 2005. The export amount of HF was 2180 tons, of which 2074 ton (China, 1422 tons, U.S. 524 tons, and Malaysia, 128 tons) was exported for the manufacturing of semiconductors. Based on the export and import amounts, it can be inferred that HF was used for manufacturing semiconductors. The industries applications of 161,123 tons of HF were as follows: manufacturing of basic inorganic chemical substance (27,937 tons), manufacturing of other chemical products such as detergents (28,208 tons), manufacturing of flat display (24,896 tons), and manufacturing of glass container package (22,002 tons). In this study, an analysis of the chemical substance flow showed that HF was mainly used in the semiconductor industry as well as glass container manufacturing. Combined with other risk management tools and approaches in the chemical industry, the chemical substance flow analysis (CSFA) can be a useful tool and method for assessment and management. The current CSFA results provide useful information for policy making in the chemical industry and national systems. Graphical abstract Hydrogen fluoride chemical substance flows in 2014 in South Korea.
  13. Botelho D, Leo BF, Massa C, Sarkar S, Tetley T, Chung KF, et al.
    Front Pharmacol, 2018;9:213.
    PMID: 29632485 DOI: 10.3389/fphar.2018.00213
    Here we examine the organ level toxicology of both carbon black (CB) and silver nanoparticles (AgNP). We aim to determine metal-specific effects to respiratory function, inflammation and potential interactions with lung lining fluid (LLF). C57Bl6/J male mice were intratracheally instilled with saline (control), low (0.05 μg/g) or high (0.5 μg/g) doses of either AgNP or CB 15 nm nanospheres. Lung histology, cytology, surfactant composition and function, inflammatory gene expression, and pulmonary function were measured at 1, 3, and 7 days post-exposure. Acutely, high dose CB resulted in an inflammatory response, increased neutrophilia and cytokine production, without alteration in surfactant composition or respiratory mechanics. Low dose CB had no effect. Neither low nor high dose AgNPs resulted in an acute inflammatory response, but there was an increase in work of breathing. Three days post-exposure with CB, a persistent neutrophilia was noted. High dose AgNP resulted in an elevated number of macrophages and invasion of lymphocytes. Additionally, AgNP treated mice displayed increased expression of IL1B, IL6, CCL2, and IL10. However, there were no significant changes in respiratory mechanics. At day 7, inflammation had resolved in AgNP-treated mice, but tissue stiffness and resistance were significantly decreased, which was accompanied by an increase in surfactant protein D (SP-D) content. These data demonstrate that the presence of metal alters the response of the lung to nanoparticle exposure. AgNP-surfactant interactions may alter respiratory function and result in a delayed immune response, potentially due to modified airway epithelial cell function.
  14. Qian M, Zhang H, Kham SK, Liu S, Jiang C, Zhao X, et al.
    Genome Res., 2017 02;27(2):185-195.
    PMID: 27903646 DOI: 10.1101/gr.209163.116
    Chromosomal translocations are a genomic hallmark of many hematologic malignancies. Often as initiating events, these structural abnormalities result in fusion proteins involving transcription factors important for hematopoietic differentiation and/or signaling molecules regulating cell proliferation and cell cycle. In contrast, epigenetic regulator genes are more frequently targeted by somatic sequence mutations, possibly as secondary events to further potentiate leukemogenesis. Through comprehensive whole-transcriptome sequencing of 231 children with acute lymphoblastic leukemia (ALL), we identified 58 putative functional and predominant fusion genes in 54.1% of patients (n = 125), 31 of which have not been reported previously. In particular, we described a distinct ALL subtype with a characteristic gene expression signature predominantly driven by chromosomal rearrangements of the ZNF384 gene with histone acetyltransferases EP300 and CREBBP ZNF384-rearranged ALL showed significant up-regulation of CLCF1 and BTLA expression, and ZNF384 fusion proteins consistently showed higher activity to promote transcription of these target genes relative to wild-type ZNF384 in vitro. Ectopic expression of EP300-ZNF384 and CREBBP-ZNF384 fusion altered differentiation of mouse hematopoietic stem and progenitor cells and also potentiated oncogenic transformation in vitro. EP300- and CREBBP-ZNF384 fusions resulted in loss of histone lysine acetyltransferase activity in a dominant-negative fashion, with concomitant global reduction of histone acetylation and increased sensitivity of leukemia cells to histone deacetylase inhibitors. In conclusion, our results indicate that gene fusion is a common class of genomic abnormalities in childhood ALL and that recurrent translocations involving EP300 and CREBBP may cause epigenetic deregulation with potential for therapeutic targeting.
  15. Ngim CF, Lee MY, Othman N, Lim SM, Ng CS, Ramadas A
    Hemoglobin, 2019 Mar;43(2):95-100.
    PMID: 31179787 DOI: 10.1080/03630269.2019.1599906
    We explored the severity and risk factors for cardiac and liver iron overload (IOL) in 69 thalassemia patients who underwent T2* magnetic resonance imaging (T2* MRI) in a Malaysian tertiary hospital from 2011 to 2015. Fifty-three patients (76.8%) had transfusion-dependent thalassemia (TDT) and 16 (23.2%) had non transfusion-dependent thalassemia (NTDT). Median serum ferritin prior to T2* MRI was 3848.0 μg/L (TDT) and 3971.0 μg/L (NTDT). Cardiac IOL was present in 16 (30.2%) TDT patients and two (12.5%) NTDT patients, in whom severe cardiac IOL defined as T2* <10 ms affected six (11.3%) TDT patients. Liver IOL was present in 51 (96.2%) TDT and 16 (100%) NTDT patients, 37 (69.8%) TDT and 13 (81.3%) NTDT patients were in the most severe category (>15 mgFe/gm dry weight). Serum ferritin showed a significantly strong negative correlation with liver T2* in both TDT (rs = -0.507, p = 0.001) and NTDT (r = -0.762, p = 0.002) but no correlation to cardiac T2* in TDT (r = -0.252, p = 0.099) as well as NTDT (r = -0.457, p = 0.100). For the TDT group, regression analysis showed that cardiac IOL was more severe in males (p = 0.022) and liver IOL was more severe in the Malay ethnic group (p = 0.028) and those with higher serum ferritin levels (p = 0.030). The high prevalence of IOL in our study and the poor correlation between serum ferritin and cardiac T2* underline the need to routinely screen thalassemia patients using T2* MRI to enable the early detection of cardiac IOL.
  16. Abdelsalam M, Eissa AE, Chen SC
    J Adv Res, 2015 Mar;6(2):233-8.
    PMID: 25750757 DOI: 10.1016/j.jare.2013.12.003
    Streptococcus dysgalactiae is an emerging pathogen of fish. Clinically, infection is characterized by the development of necrotic lesions at the caudal peduncle of infected fishes. The pathogen has been recently isolated from different fish species in many countries. Twenty S. dysgalactiae isolates collected from Japan, Taiwan, Malaysia and Indonesia were molecularly characterized by biased sinusoidal field gel electrophoresis (BSFGE) using SmaI enzyme, and tuf gene sequencing analysis. DNA sequencing of ten S. dysgalactiae revealed no genetic variation in the tuf amplicons, except for three strains. The restriction patterns of chromosomal DNA measured by BSFGE were differentiated into six distinct types and one subtype among collected strains. To our knowledge, this report gives the first snapshot of S. dysgalactiae isolates collected from different countries that are localized geographically and differed on a multinational level. This genetic unrelatedness among different isolates might suggest a high recombination rate and low genetic stability.
  17. Cheng J, Wang Y, Hou J, Luo D, Xie Q, Ning Q, et al.
    J. Clin. Virol., 2014 Dec;61(4):509-16.
    PMID: 25200354 DOI: 10.1016/j.jcv.2014.08.008
    In mainland China, peginterferon (PEG-IFN) alfa-2b 1.0μg/kg/wk for 24 weeks is the approved treatment for HBeAg-positive chronic hepatitis B.
  18. Sung YY, Ashame MF, Chen S, Macrae TH, Sorgeloos P, Bossier P
    J. Fish Dis., 2009 Aug;32(8):675-85.
    PMID: 19515074 DOI: 10.1111/j.1365-2761.2009.01046.x
    Among their numerous physiological effects, heat shock proteins (Hsps) are potent immunomodulators, a characteristic reflecting their potential as therapeutic agents and which led to their application in combating infection. As an example, the up-regulation of endogenous Hsp70 in the branchiopod crustacean Artemia franciscana (Kellogg) is concurrent with shielding against bacterial infection. To better understand this protective mechanism, gnotobiotic Artemia were fed with Escherichia coli treated to over-produce different prokaryotic Hsps. This was shown to increase larval resistance to experimental Vibrio campbellii exposure. Immunoprobing of Western blots showed that the enhanced resistance to V. campbellii correlated with DnaK production in E coli. A definitive role for DnaK was then demonstrated by feeding Artemia larvae with transformed bacteria over-producing only this protein, although other Hsps such as DnaJ and grpE also provided tolerance against Vibrio infection. Feeding of bacteria synthesizing selected Hsps is therefore suggested as an alternative to antibiotic use as a means of enhancing resistance of Artemia larvae to bacterial infection, which may have potential applications in aquaculture.
  19. Othman WN, Muttalib KA, Bakri R, Doss JG, Jaafar N, Salleh NC, et al.
    J Public Health Dent, 2006;66(3):199-204.
    PMID: 16913247
    To translate and validate the Geriatric Oral Health Assessment Index (GOHAI into the Malay language for use in Malaysia.
  20. Chen ST, Soo KL, Azriani AR, Van Rostenberghe H, Sakinah H
    Malays J Nutr, 2012 Aug;18(2):185-205.
    PMID: 24575666 MyJurnal
    Persons with disabilities (PWD) are susceptible to malnutrition. Caregivers or teachers in rehabilitation centres may not be adequately trained in nutrition management of PWD. The aims of this study were (i) to assess the nutrition knowledge, attitude and practice among teachers in community-based rehabilitation centres for PWD; and (ii) to evaluate changes in the nutrition knowledge and attitude of the teachers before and after exposure to a training workshop on nutrition management for PWD.
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