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Sukumaran V, Cosh J, Thammavong A, Kennedy K, Ong CW. Vancomycin dependent Enterococcus: an unusual mutant? Pathology 2019; 51:318-320. [PMID: 30846227 DOI: 10.1016/j.pathol.2018.11.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 11/05/2018] [Indexed: 11/17/2022]
Affiliation(s)
- Vichitra Sukumaran
- Department of Microbiology, The Canberra Hospital, Canberra, ACT, Australia.
| | - Jacqueline Cosh
- Department of Microbiology, The Canberra Hospital, Canberra, ACT, Australia
| | - Aline Thammavong
- Department of Microbiology, The Canberra Hospital, Canberra, ACT, Australia
| | - Karina Kennedy
- Department of Microbiology, The Canberra Hospital, Canberra, ACT, Australia; Department of Infectious Diseases, The Canberra Hospital, Canberra, ACT, Australia; Australian National University Medical School, Canberra, ACT, Australia
| | - Chong Wei Ong
- Department of Microbiology, The Canberra Hospital, Canberra, ACT, Australia; Department of Infectious Diseases, The Canberra Hospital, Canberra, ACT, Australia
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Affiliation(s)
- C W Ong
- Microbiology Department, The Canberra HospitalCanberra, Australian Capital Territory, Australia
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Wilson HL, Ong CW. Bifidobacterium longum vertebrodiscitis in a patient with cirrhosis and prostate cancer. Anaerobe 2017; 47:47-50. [PMID: 28408274 DOI: 10.1016/j.anaerobe.2017.04.004] [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: 01/20/2017] [Revised: 04/07/2017] [Accepted: 04/08/2017] [Indexed: 11/30/2022]
Abstract
Bifidobacterium species are anaerobic, Gram-positive bacilli that colonize the human intestinal tract and oral cavity. They are an infrequent cause of invasive human infection. We report a case of Bifidobacterium longum lumbar vertebrodiscitis in a 71 year old man who was subsequently diagnosed with liver cirrhosis and prostate cancer. The clinical outcome was good following antibiotic treatment with penicillin and clindamycin. The laboratory identification of Bifidobacterium species and risk factors for invasive infection are discussed.
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Affiliation(s)
- Heather L Wilson
- Canberra Hospital and Health Services, PO Box 11, Woden, ACT 2606, Australia.
| | - Chong Wei Ong
- Canberra Hospital and Health Services, PO Box 11, Woden, ACT 2606, Australia
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Chan BT, Ong CW, Lim E, Abu Osman NA, Al Abed A, Lovell NH, Dokos S. Simulation of left ventricle flow dynamics with dilated cardiomyopathy during the filling phase. Annu Int Conf IEEE Eng Med Biol Soc 2013; 2012:6289-92. [PMID: 23367367 DOI: 10.1109/embc.2012.6347432] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Dilated cardiomyopathy (DCM) is a common cardiac disease which leads to the deterioration in cardiac performance. A computational fluid dynamics (CFD) approach can be used to enhance our understanding of the disease, by providing us with a detailed map of the intraventricular flow and pressure distributions. In the present work, effect of ventricular size on the intraventricular flow dynamics and intraventricular pressure gradients (IVPGs) was studied using two different implementation methods, i.e. the geometry-prescribed and the fluid structure interaction (FSI) methods. Results showed that vortex strength and IVPGs are significantly reduced in a dilated heart, leading to an increased risk of thrombus formation and impaired ventricular filling. We suggest FSI method as the ultimate method in studying ventricular dysfunction as it provides additional cardiac disease prognostic factors and more realistic model implementation.
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Affiliation(s)
- B T Chan
- Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia.
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Jackson J, McGregor A, Cooley L, Ng J, Brown M, Ong CW, Darcy C, Sintchenko V. Francisella tularensis subspecies holarctica, Tasmania, Australia, 2011. Emerg Infect Dis 2013; 18:1484-6. [PMID: 22931809 PMCID: PMC3437722 DOI: 10.3201/eid1809.111856] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We report a case of ulceroglandular tularemia that developed in a woman after she was bitten by a ringtail possum (Pseudocheirus peregrinus) in a forest in Tasmania, Australia. Francisella tularensis subspecies holarctica was identified. This case indicates the emergence of F. tularensis type B in the Southern Hemisphere.
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Srivastava S, Wong KF, Ong CW, Huak CY, Yeoh KG, Teh M, Luk JM, Salto-Tellez M. A morpho-molecular prognostic model for hepatocellular carcinoma. Br J Cancer 2012; 107:334-9. [PMID: 22713659 PMCID: PMC3394972 DOI: 10.1038/bjc.2012.230] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Background: Hepatocellular carcinoma (HCC) is the third common cause of cancer-related deaths and its prognostication is still suboptimal. The aim of this study was to establish a new prognostication algorithm for HCC. Methods: In all, 13 biomarkers related to the etiopathogenesis of HCC were evaluated by immunohistochemistry using tissue microarrays containing 121 primary HCC resection cases, and validated in subsequent cohort of 85 HCC cases. The results were compared with Affymetrix Gene Chip Human Genome U133Plus microarray data in a separate cohort of 228 HCC patients. Results: On immunohistochemical evaluation and multivariate Cox regression analysis p53, alpha fetaprotein (AFP), CD44 and CD31, tumour size and vascular invasion, were significant predictors for worse survival in HCC patients. A morpho-molecular prognostic model (MMPM) was constructed and it was a significant independent predictor for overall survival (OS) and relapse-free survival (RFS) (P<0.000). The OS and RFS of HCClow was higher (104 and 78 months) as compared with HCChigh (73 and 43 months) (P<0.0001for OS and RFS). Hepatocellular carcinoma patients with higher stage (III+IV), >5 cm tumour size, positive vascular invasion and satellitosis belonged to HCChigh group. The validation group reproduced the same findings. Gene expression analysis confirmed that 7 of the 12 biomarkers were overexpressed in >50% of tumour samples and significant overexpression in tumour samples was observed in AFP, CD31, CD117 and Ki-67 genes. Conclusion: The MMPM, based on the expression of selected proteins and clinicopathological parameters, can be used to classify HCC patients between good vs poor prognosis and high vs low risk of recurrence following hepatic resection.
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Affiliation(s)
- S Srivastava
- Cancer Science Institute, National University of Singapore, Singapore
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Ong CW, Chan BT, Lim E, Abu Osman NA, Abed AA, Dokos S, Lovell NH. Fluid structure interaction simulation of left ventricular flow dynamics under left ventricular assist device support. Annu Int Conf IEEE Eng Med Biol Soc 2012; 2012:6293-6296. [PMID: 23367368 DOI: 10.1109/embc.2012.6347433] [Citation(s) in RCA: 2] [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] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
For patient's receiving mechanical circulatory support, malfunction of the left ventricular assist device (LVADs) as well as mal-positioning of the cannula imposes serious threats to their life. It is therefore important to characterize the flow pattern and pressure distribution within the ventricle in the presence of an LVAD. In this paper, we present a 2D axisymmetric fluid structure interaction model of the passive left ventricle (LV) incorporating an LVAD cannula to simulate the effect of the LVAD cannula placement on the vortex dynamics. Results showed that larger recirculation area was formed at the cannula tip with increasing cannula insertion depth, and this is believed to reduce the risk of thrombus formation. Furthermore, we also simulated suction events (collapse of the LV) by closing the inlet. Vortex patterns were significantly altered under this condition, and the greatest LV wall displacement was observed at the part of the myocardium closest to the cannula tip.
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Affiliation(s)
- C W Ong
- Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia
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Zhao M, Huang JX, Wong MH, Tang YM, Ong CW. Versatile computer-controlled system for characterization of gas sensing materials. Rev Sci Instrum 2011; 82:105001. [PMID: 22047322 DOI: 10.1063/1.3648132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Design of a system used for characterizing gas sensing materials is described. It is distinctive of being able to measure electrical and optical responses of a sample simultaneously, control a number of measurement parameters, perform fast exchange of gaseous environment, and be fully controlled automatically. These features make the system to be versatile in determining most concerned performance indexes of a gas sensing material (e.g., sensitivity, stability, selectivity, response/recovery times, etc.) as functions of various combinations of measurement conditions (e.g., gas concentrations, temperature, total pressure, content of interferants, photo assist, relative humidity, soaking time in a fixed gas concentration, and number of switching cycles in a dynamic test, etc.). Rationales of the designs associated with general gas sensing mechanics are discussed.
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Affiliation(s)
- M Zhao
- Department of Applied Physics and Materials Research Center, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
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Wang T, Ong CW, Shi J, Srivastava S, Yan B, Cheng CL, Yong WP, Chan SL, Yeoh KG, Iacopetta B, Salto-Tellez M. Sequential expression of putative stem cell markers in gastric carcinogenesis. Br J Cancer 2011; 105:658-65. [PMID: 21829201 PMCID: PMC3188930 DOI: 10.1038/bjc.2011.287] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Gastric carcinogenesis has been well documented in the step-wise histopathological model, known as Correa pathway. Several biomarkers including CD44, Musashi-1 and CD133 have been reported as putative stem cell (PSC) markers. METHODS We investigated expression of PSC markers CD44, Musashi-1 and CD133 in relation to gastric carcinogenesis and prognosis and chemoresponse. Immunohistochemistry staining was performed in gastric cancer (GC) clinical specimens representing different steps of the Correa pathway. Gastric cancer samples taken before and after neoadjuvant chemotherapy with docetaxel, cisplatin and capecitabine (DCX) were also evaluated for PSC marker expression. RESULTS We showed that the expression of three PSC markers was significantly elevated in GC relative to normal gastric mucosa (P<0.001 for each marker). Precancerous lesions, including intestinal metaplasia and dysplasia, demonstrated increased expression of CD44 and Musashi-1. CD133 was predominantly expressed along the border between intramucosal carcinoma and connective tissue at later stages. High CD44 and CD133 expression showed prognostic value for worse patient survival (P=0.014 and P=0.019, respectively). A small number of tumours with high expression of CD44 and CD133 showed pathological response to DCX-based neoadjuvant chemotherapy. CONCLUSION CD44 and Musashi-1 are frequently expressed in both premalignant gastric lesions and invasive GC, whereas CD133 expression is restricted mainly to neoplastic tissues.
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Affiliation(s)
- T Wang
- Cancer Science Institute, National University Health System and Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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Ong CW, Chua LS, Ng A, Low SY. Langerhans cell histiocytosis with hypogonadotrophic hypogonadism. Singapore Med J 2009; 50:e185-e188. [PMID: 19495506] [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: 05/27/2023]
Abstract
Langerhans cell histiocytosis (LCH) is a rare disease characterised by monoclonal proliferation and infiltration of organs by large mononuclear cells. Organs commonly involved include the lungs and pituitary gland. However, the disease association with hypogonadotrophic hypogonadism has not been reported in the literature, to our knowledge. We report a 26-year-old Chinese man with LCH, recurrent pneumothoraces, diabetes insipidus and hypogonadotrophic hypogonadism. The clinical features and management of the disease are reviewed.
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Affiliation(s)
- C W Ong
- Division of Infectious Diseases, Department of Medicine, National University Hospital, 5 Lower Kent Ridge Road, Singapore.
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Abstract
A series of bithienyl-pyrimidines having cationic side chain have been developed as antitumor agents. This work illustrates the overwhelming importance of the bithienyl unit for efficient DNA binding. The X-ray structure of 4-(2',2"-thien-5-yl)2-chloropyrimidine was obtained for postulating the conformation of the bithienyl-pyrimidine moiety.
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Affiliation(s)
- Y M Chou
- Department of Chemistry, National Sun Yat Sen University, Kaoshiung, Taiwan
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Abstract
Aiming to develop anticancer agents, synthesis and in vitro evaluation of aromatic dienyl diketone derivatives were carried out. All the aromatic (Z.E)-dienyl diketones synthesized exhibit strong in vitro inhibition of tumor cell growth against Colon cell line.
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Affiliation(s)
- P C Shieh
- Department of Pharmacy, Tajen Junior College of Pharmacy, Ping-Tung, Taiwan
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Sheh L, Chang HW, Ong CW, Chen SL, Bailly C, Linssen RC, Waring MJ. Synthesis, DNA binding, and sequence specificity of DNA alkylation by some novel cyclic peptide-chlorambucil conjugates. Anticancer Drug Des 1995; 10:373-88. [PMID: 7639928] [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] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In an effort to investigate the potential of cyclic peptides as carriers for cytotoxic agents, we synthesized four cyclic peptide-chlorambucil conjugates: cyclo[Lys(CHB)-Lys(CHB)-Gaba-] (peptide Y), cyclo[Lys(CHB)-Gly-Lys(CHB)-Gaba-] (peptide A), cyclo[Lys(CHB)-beta-Ala-Lys(CHB)-Gaba-] (peptide B) and cyclo[Lys(CHB)-Gaba-Lys(CHB)-Gaba-] (peptide C). The cyclic peptides were synthesized by coupling protected amino acid residues in solution and the subsequent cyclization was performed by the pentafluorophenyl ester method as described previously (Sheh et al., 1990, 1993a,b). After deblocking the lysyl-carbobenzyloxy protecting group (Z), the conjugation was achieved by reaction with the pentafluorophenyl ester of chlorambucil (CHB). These cyclic peptides differ from one another in ring size and are disubstituted with CHB via the epsilon-amino group of the lysyl residue. The various conjugates were designed to study the effect of ring size on the mode of DNA binding and alkylation. A DNA-binding assay using lambda-DNA with ethidium bromide showed that whereas peptide Y and CHB have no observable binding affinity, the apparent binding constants for peptide A, peptide B and peptide C on lambda-DNA were determined to be 2.36 x 10(5), 1.27 x 10(5) and 3.50 x 10(5), respectively. Thus, it is suggested that cyclic peptides bearing aliphatic side chains attached to a ring larger in size than 14 members would be more favourable as regards augmenting the binding affinity. DNase I footprinting showed that no footprinting patterns were observed for the 253-mer fragment and 117-mer fragment with peptide A, but two new bands corresponding to G69 and G80 were observed for the 117-mer fragment. DNA alkylation studies using a piperidine cleavage assay on the 117-mer DNA fragment showed that the sequence selectivity, judged by reaction intensity observed with peptide A, peptide B and peptide C, was similar to that seen with CHB alone. The selectivity of alkylation for both CHB and its peptide derivatives appears to be: 3'-Pur-G-Pyr-5' > 3'-Pyr-G-Pyr-5' > 3'-Pyr-G-Pur-5' = 3'Pur-G-Pur-5'. However, there are apparent differences in the intensity of alkylation by peptides A, B, C and CHB at certain guanine residues.
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Affiliation(s)
- L Sheh
- Department of Chemistry, Tunghai Christian University, Taichung, Taiwan, Republic of China
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Shen ZX, Ong CW, Tang SH, Kuok MH. Spectroscopic evidence of pressure-induced amorphization in alpha -NaVO3. Phys Rev B Condens Matter 1994; 49:1433-1436. [PMID: 10010456 DOI: 10.1103/physrevb.49.1433] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Lown JW, Sondhi SM, Ong CW, Skorobogaty A, Kishikawa H, Dabrowiak JC. Deoxyribonucleic acid cleavage specificity of a series of acridine- and acodazole-iron porphyrins as functional bleomycin models. Biochemistry 1986; 25:5111-7. [PMID: 2429695 DOI: 10.1021/bi00366a020] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A series of metalloporphyrins linked through basic chains to certain DNA interactive groups has been synthesized. Several of these agents reproduce the characteristic properties of the antitumor glycopeptide bleomycin, including the oxygen-mediated scission of DNA in the presence of thiols, antibiobic activity under aerobic conditions, and activity against human and animal tumor models. Initial screening by scission of PM2-CCC-DNA identified six of the compounds, including those bearing acridine and acodazole intercalating groups, as the most active. The specificity of the oxygen-mediated scission of a 139 base pair HindIII/NciI restriction fragment of pBR322 by these six selected agents was then determined and compared with the action of pancreatic DNase by densitometric scans. All six of these compounds produce uniform base and sequence neutral cleavage of the restriction fragment at each base site. The six active compounds bear either of two types of intercalators, 6-chloro-2-methoxyacridine or acodazole, and with linkages to the ferric binding domain of -NH(CH2)2-, -NH(CH2)3-, -NH(CH2)4-, or -NH(CH2)3NH(CH2)3- and either porphyrin or deuteroporphyrin moieties. Comparison of the Kassoc values for binding to calf thymus DNA suggests that the enhanced binding observed with the linker -NH(CH2)3NH(CH2)3- contributes to the efficiency of sequence neutral DNA scission and may be a factor in the relative anticancer activities of these agents. The iron porphyrins give no evidence of the production of base propenals in DNA degradation, and the autoradiograms clearly indicate that a phosphate group is attached to the 5' end of the oligomer. The scission is partially suppressible by catalase and superoxide dismutase.(ABSTRACT TRUNCATED AT 250 WORDS)
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Fang LS, Ong CW, Hwang WS. A comparative study on the binding characteristics of the tight serum biliverdin-protein complexes in two fishes: Anguilla japonica and Clinocottus analis. Comp Biochem Physiol B 1986; 84:393-6. [PMID: 3743032 DOI: 10.1016/0305-0491(86)90096-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The binding characteristics of biliverdin to its carrier protein in the blue-green blood of Clinocottus analis (woolly sculpin) and Anguilla japonica (freshwater eel) were operationally defined by various chemical probing methods and spectra analysis. The biliverdin in C. analis is a rotatable coiled molecule enveloped in a hydrophobic pocket of its carrier protein. The biliverdin in A. japonica is an open form molecule with external hydrogen bond or weak ester bond interacting with the carrier protein. This, for the first time, shows that the novel firm binding biliprotein complexes in the blood of different species are biochemically different. Their comparative and evolutionary significance is discussed.
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