Displaying publications 1 - 20 of 26 in total

  1. Lee CH, Abidin UZ
    Biochem. Int., 1989 Oct;19(4):745-53.
    PMID: 2559728
    Cyclic AMP phosphodiesterase (PDE) partially purified from roots of Vigna mungo exhibited optimum activity at pH 5.5 to 6.0 and maximum enzyme activity at 50 degrees C. Levels of PDE activity in roots remained relatively constant from the first to the eleventh day after germination; on the twelfth day there was a 400% increase in PDE activity. The enzyme was stable for at least 48 hours at 28 degrees C, retaining 92% of its original activity. Plant growth hormones including gibberellic acid, indoleacetic acid and kinetin at 1.0 and 10.0 microM concentrations did not have any significant effect on enzyme activity. Nucleotides tested including cyclic 2'3' AMP, cyclic 2'3' GMP completely abolished enzyme activity at 1.0mM while cyclic 3'5' GMP, cyclic 3'5' GMP, 2'deoxy 5' ATP, 2'deoxy 5'GTP and 5'ADP were also inhibitory to the enzyme. The enzyme was stimulated by Mg2+, Fe2+ and NH4+ while Cu2+ and Fe3+ were inhibitory. Theophylline, caffeine, phosphate, pyrophosphate and EDTA were inhibitory to the enzyme.
  2. Lee CH, Raman S, Sivanesaratnam V
    Int J Gynaecol Obstet, 1989 Jan;28(1):21-5.
    PMID: 2565826
    Torsion of ovarian tumors occurred predominantly in the reproductive age group. The majority of the cases presented in pregnant (22.7%) than in non-pregnant (6.1%) women. The major presenting symptom was pain but an abdominal mass was palpable in 79.4% of cases. Torsion was more common on the right ovary and 50% were gangrenous at laparotomy. Most of the tumors were benign cystic teratomas. Only 8.7% of the tumors were malignant.
  3. Lee CH, Ngeow YF
    Med. J. Malaysia, 1983 Mar;38(1):23-6.
    PMID: 6633329
    Genital discharge from patients unth. smear positive gonorrhoea was transported from the clinic to the laboratory in. Stuart's transport medium (Oxoid CM 111). Within. six hours of transit time the recovery rate of gonococci was 94%. When compared with "bedside" inoculation onto Modified Thayer Martin medium, there was no significant difference in recovery rates up to 6 hours of transportation in Stuart's transport medium, However, the rate of isolation of gonococci was significantly reduced after 20 to 30 hours of transportation. It is concluded that Stuart's transport medium is an acceptable transport medium for specimens containing gonococci when specimens reach the laboratory within 6 hours of collection.
  4. Lee CH, Sharif SZ
    Med. J. Malaysia, 2016 Jun;71(3):149-51.
    PMID: 27495893 MyJurnal
    Breast tuberculosis (TB) is rare even in endemic countries. Most of these cases occur as secondary TB due to a concurrent infection. Primary breast TB is diagnosed when it is the only site of disease without other foci of infection. The presentation of primary breast TB may often mimic carcinoma of the breast. While imaging is not specific, histopathology provides a definitive diagnosis. Here, we present a case of primary breast TB in a breast cancer patient and review the literature.
  5. Lee CH, Kuo CN, Chen HL, Chen CY
    Nat. Prod. Res., 2013;27(11):988-91.
    PMID: 22691063 DOI: 10.1080/14786419.2012.695369
    This review describes the morphological, phytochemical and pharmacological properties of Cinnamomum subavenium (Lauraceae). The plant grows wild in southern Mainland China, Burma, Cambodia, Taiwan, Malaysia and Indonesia. This plant is recorded as having long been used to treat carcinomatous swelling, stomach ache, chest pain, abdominal pain, hernia, diarrhoea, rheumatism, nausea and vomiting. This article enumerates an overview of phytochemical and pharmacological aspects that is useful to researchers for further exploration for the necessary development of this potential herb.
  6. Ngeow YF, Hema V, Zakaria M, Lee CH, Ramachandran S
    Malays J Pathol, 1997 Dec;19(2):127-32.
    PMID: 10879253
    First-void urine samples collected from sexually transmitted diseases (STD) clinic patients were examined by a nested polymerase chain reaction (PCR) and a commercial enzyme immunoassay (IDEIA Chlamydia) for the diagnosis of Chlamydia trachomatis urethritis or cervicitis. The primers for the PCR amplified a target in the major outer membrane protein (MOMP) gene in C trachomatis while the IDEIA detected genus-specific chlamydial lipopolysaccharide. Discrepant results were resolved by retesting urine specimens with a second (plasmid-based) PCR and taking urethral or endocervical swab results into consideration. For 231 men (chlamydial prevalence 20.4%), the sensitivity, specificity, positive and negative predictive values were 59.6%, 99.5%, 96.6% and 90.6% for urine IDEIA, 68.1%, 99.5%, 97% and 92.4% for urethral swab IDEIA and 97.9%, 99.5%, 97.9% and 99.5% for urine PCR. The corresponding rates for 66 women (chlamydial prevalence 54.6%) were 19.4%, 100%, 100% and 50.8% for urine IDEIA, 86.1%, 96.7%, 96.9% and 85.3% for endocervical swab IDEIA and 91.7%, 93.3%, 94.3% and 90.3% for urine PCR. Hence, in a high prevalence population, the urine IDEIA was a suitable alternative to the male urethral swab IDEIA but significantly less sensitive than the endocervical swab IDEIA. The urine PCR was, however, much more sensitive than the urine IDEIA for both men and women and could replace the endocervical swab IDEIA for the diagnosis of chlamydial cervicitis.
  7. Lee CH, Sapuan SM, Lee JH, Hassan MR
    Springerplus, 2016;5(1):1680.
    PMID: 27733982
    A study of the melt volume flow rate (MVR) and the melt flow rate (MFR) of kenaf fibre (KF) reinforced Floreon (FLO) and magnesium hydroxide (MH) biocomposites under different temperatures (160-180 °C) and weight loadings (2.16, 5, 10 kg) is presented in this paper. FLO has the lowest values of MFR and MVR. The increment of the melt flow properties (MVR and MFR) has been found for KF or MH insertion due to the hydrolytic degradation of the polylactic acid in FLO. Deterioration of the entanglement density at high temperature, shear thinning and wall slip velocity were the possible causes for the higher melt flow properties. Increasing the KF loadings caused the higher melt flow properties while the higher MH contents created stronger bonding for higher macromolecular chain flow resistance, hence lower melt flow properties were recorded. However, the complicated melt flow behaviour of the KF reinforced FLO/MH biocomposites was found in this study. The high probability of KF-KF and KF-MH collisions was expected and there were more collisions for higher fibre and filler loading causing lower melt flow properties.
  8. Liam CK, Ruthranesan M, Lee CH, Pang YK, Chua KT, Lim BK
    Asia Pac J Clin Oncol, 2012 Sep;8(3):267-74.
    PMID: 22897510 DOI: 10.1111/j.1743-7563.2011.01509.x
    To evaluate the response and progression-free survival (PFS) of Malaysian patients with advanced lung adenocarcinoma and unknown epidermal growth factor receptor (EGFR) mutation status treated with gefitinib.
  9. Lee CH, Liam CK, Pang YK, Chua KT, Lim BK, Lai NL
    Lung Cancer, 2011 Nov;74(2):349-51.
    PMID: 21920622 DOI: 10.1016/j.lungcan.2011.08.008
    We report a woman presenting with respiratory failure due to a right-sided pleural effusion, lung metastases and lymphangitis carcinomatosis from advanced lung adenocarcinoma in the third trimester of pregnancy, who showed good response to EGFR tyrosine kinase inhibitor.
  10. Shukor MY, Rahman MF, Shamaan NA, Lee CH, Karim MI, Syed MA
    Appl. Biochem. Biotechnol., 2008 Mar;144(3):293-300.
    PMID: 18556818
    Molybdenum-reducing activity in the heterotrophic bacteria is a phenomenon that has been reported for more than 100 years. In the presence of molybdenum in the growth media, bacterial colonies turn to blue. The enzyme(s) responsible for the reduction of molybdenum to molybdenum blue in these bacteria has never been purified. In our quest to purify the molybdenum-reducing enzyme, we have devised a better substrate for the enzyme activity using laboratory-prepared phosphomolybdate instead of the commercial 12-phosphomolybdate we developed previously. Using laboratory-prepared phosphomolybdate, the highest activity is given by 10:4-phosphomolybdate. The apparent Michaelis constant, Km for the laboratory-prepared 10:4-phosphomolybdate is 2.56 +/- 0.25 mM (arbitrary concentration), whereas the apparent V(max) is 99.4 +/- 2.85 nmol Mo-blue min(-1) mg(-1) protein. The apparent Michaelis constant or Km for NADH as the electron donor is 1.38 +/- 0.09 mM, whereas the apparent V(max) is 102.6 +/- 1.73 nmol Mo-blue min(-1) mg(-l) protein. The apparent Km and V(max) for another electron donor, NADPH, is 1.43 +/- 0.10 mM and 57.16 +/- 1.01 nmol Mo-blue min(-1) mg(-1) protein, respectively, using the same batch of molybdenum-reducing enzyme. The apparent V(max) obtained for NADH and 10:4-phosphomolybdate is approximately 13 times better than 12-phoshomolybdate using the same batch of enzyme, and hence, the laboratory-prepared phosphomolybdate is a much better substrate than 12-phoshomolybdate. In addition, 10:4-phosphomolybdate can be routinely prepared from phosphate and molybdate, two common chemicals in the laboratory.
  11. Ayu RS, Khalina A, Harmaen AS, Zaman K, Jawaid M, Lee CH
    Polymers (Basel), 2018 Oct 25;10(11).
    PMID: 30961112 DOI: 10.3390/polym10111187
    In this study, polybutylene succinate (PBS) was blended with five types of modified tapioca starch to investigate the effect of modified tapioca starch in PBS blends for food packaging by identifying its properties. Tensile and flexural properties of blends found deteriorated for insertion of starch. This is due to poor interface, higher void contents and hydrolytic degradation of hydrophilic starch. FTIR results show all starch/PBS blends are found with footprints of starch except OH stretching vibration which is absent in B40 blends. Besides, Broad O⁻H absorption in all specimens show that these are hydrogen bonded molecules and no free O⁻H bonding was found. SEM testing shows good interfacial bonding between PBS and starch except E40 blends. Therefore, poor results of E40 blends was expected. In TGA, a slightly weight loss found between 80 to 100 °C due to free water removal. Apart from this, insertion of all types of starch reduces thermal stability of blend. However, high crystallinity of starch/PBS blend observed better thermal stability but lower char yield. Starch A and B blends are suggested to be used as food wrap and food container materials while starch D blend is suitable for grocery plastic bags according to observed results.
  12. Xie CB, Chan MY, Teo SG, Low AF, Tan HC, Lee CH
    Singapore Med J, 2011 Nov;52(11):835-9.
    PMID: 22173254
    There is a paucity of data on acute myocardial infarction (AMI) in young Asian women and of comparative data among various ethnic groups with respect to risk factor profile and clinical outcomes. We present a comprehensive overview of the clinical characteristics of young Asian women with AMI and a comparative analysis among Chinese, Malay and Indian women in a multi-ethnic Asian country.
  13. Lee TH, Lee CH, Azmi NA, Supparmaniam K, Wong S, Znati M, et al.
    Chem. Biodivers., 2019 Nov 13.
    PMID: 31721431 DOI: 10.1002/cbdv.201900419
    This work investigated the polar (PC: protein, amino acid and metabolite) and non-polar (NPC: fatty acid) compounds and bioactivity characteristics of the EBN harvested from the state of Johor in Malaysia. The electrophoretic gels exhibited 15 protein bands (16-173 kD) with unique protein profile. Amino acids analysis by AccQ•Tag method revealed 18 types of amino acids in EBN. Metabolite profiling was performed using High-Performance Liquid Chromatography coupled with Quadrupole Time-of-Flight Mass Spectrometer (HPLC-QTOF/MS) technique and a total of 54 compounds belonging to different groups were detected and identified. These findings help to uncover the relation of therapeutic activity of EBN. The EBN was further extracted with EtOAC and n-BuOH. The EtOAc extract was fractionated into 3 fractions (F1-F3), and the high triglyceride content in F2 was verified by GC-FID. The three groups of fatty acids discovered in EBN are 48.43% of poly-unsaturated (PUFA), 25.35% of saturated fatty acids (SFA) and 24.74% of mono-unsaturated fat (MUFA). These results were first to report EBN n-BuOH and EtOAc extracts and fraction F2 (TEBN) were analyzed for their antioxidant activity by the DPPH, ABTS and catalase assay and for their paraoxanase and anti-tyrosinase activities. The results showed that TEBN exhibited the significant bioactivity determination in all assays. These findings suggest that TEBN is a good source for natural bioactive compounds in promoting body vigour. Current work widened the content of EBN especially on the triglyceride and also marked the content of specific location (Johor, Malaysia) of EBN origin.
  14. Oung QW, Muthusamy H, Lee HL, Basah SN, Yaacob S, Sarillee M, et al.
    Sensors (Basel), 2015 Aug 31;15(9):21710-45.
    PMID: 26404288 DOI: 10.3390/s150921710
    Parkinson's Disease (PD) is characterized as the commonest neurodegenerative illness that gradually degenerates the central nervous system. The goal of this review is to come out with a summary of the recent progress of numerous forms of sensors and systems that are related to diagnosis of PD in the past decades. The paper reviews the substantial researches on the application of technological tools (objective techniques) in the PD field applying different types of sensors proposed by previous researchers. In addition, this also includes the use of clinical tools (subjective techniques) for PD assessments, for instance, patient self-reports, patient diaries and the international gold standard reference scale, Unified Parkinson Disease Rating Scale (UPDRS). Comparative studies and critical descriptions of these approaches have been highlighted in this paper, giving an insight on the current state of the art. It is followed by explaining the merits of the multiple sensor fusion platform compared to single sensor platform for better monitoring progression of PD, and ends with thoughts about the future direction towards the need of multimodal sensor integration platform for the assessment of PD.
  15. Lee CH, Ko AM, Yang FM, Hung CC, Warnakulasuriya S, Ibrahim SO, et al.
    JAMA Psychiatry, 2018 03 01;75(3):261-269.
    PMID: 29417149 DOI: 10.1001/jamapsychiatry.2017.4307
    Importance: Betel-quid (BQ) is the fourth most popular psychoactive agent worldwide. An emerging trend across Asia is the addictive consumption of BQ, which is associated with oral cancer and other health consequences.

    Objective: To investigate the validity and pattern of DSM-5-defined BQ use disorder (BUD) and its association with oral potentially malignant disorder (OPMD) among Asian populations.

    Design, Setting, and Participants: In-person interviews were conducted from January 1, 2009, to February 28, 2010, among a random sample of 8922 noninstitutionalized adults from the Asian Betel-quid Consortium study, an Asian representative survey of 6 BQ-endemic populations. Statistical analysis was performed from January 1, 2015, to December 31, 2016.

    Main Outcomes and Measures: Participants were evaluated for BUD using DSM-5 criteria for substance use disorder and for OPMD using a clinical oral examination. Current users of BQ with 0 to 1 symptoms were classified as having no BUD, those with 2 to 3 symptoms as having mild BUD, those with 4 to 5 symptoms as having moderate BUD, and those with 6 or more symptoms as having severe BUD.

    Results: Among the 8922 participants (4564 women and 4358 men; mean [SD] age, 44.2 [0.2] years), DSM-5 symptoms showed sufficient unidimensionality to act as a valid measure for BUD. The 12-month prevalence of DSM-5-defined BUD in the 6 study populations was 18.0% (mild BUD, 3.2%; moderate BUD, 4.3%; and severe BUD, 10.5%). The 12-month proportion of DSM-5-defined BUD among current users of BQ was 86.0% (mild BUD, 15.5%; moderate BUD, 20.6%; and severe BUD, 50.0%). Sex, age, low educational level, smoking, and drinking were significantly associated with BUD. Among individuals who used BQ, family use, high frequency of use, and amount of BQ used were significantly linked to moderate to severe BUD. Compared with individuals who did not use BQ, those who used BQ and had no BUD showed a 22.0-fold (95% CI, 4.3-112.4) risk of OPMD (P 

  16. Aisyah HA, Paridah MT, Khalina A, Sapuan SM, Wahab MS, Berkalp OB, et al.
    Polymers (Basel), 2018 Nov 28;10(12).
    PMID: 30961245 DOI: 10.3390/polym10121320
    The effects of different fabric materials namely weave designs (plain and satin) and fabric counts (5 × 5 and 6 × 6) on the properties of laminated woven kenaf/carbon fibre reinforced epoxy hybrid composites were evaluated. The hybrid composites were fabricated from two types of fabric, i.e., woven kenaf that was made from a yarn of 500tex and carbon fibre, by using vacuum infusion technique and epoxy resin as matrix. The panels were tested for tensile, flexural, and impact strengths. The results have revealed that plain fabric is more suitable than satin fabric for obtaining high tensile and impact strengths. Using a fabric count of 5 × 5 has generated composites that are significantly higher in flexural modulus as compared to 6 × 6 which may be attributed to their structure and design. The scanned electron micrographs of the fractured surfaces of the composites demonstrated that plain woven fabric composites had better adhesion properties than satin woven fabric composites, as indicated by the presence of notably lower amount of fibre pull out.
  17. Lee BW, Park JG, Ha TKQ, Pham HTT, An JP, Noh JR, et al.
    J. Nat. Prod., 2019 Aug 23;82(8):2201-2210.
    PMID: 31393125 DOI: 10.1021/acs.jnatprod.9b00224
    Melicope pteleifolia has long been consumed as a popular vegetable and tea in Southeast Asian countries, including Malaysia and southern mainland China, and is effective in the treatment of colds and inflammation. In the search for active metabolites that can explain its traditional use as an antipyretic, six new phloroacetophenone derivatives (3-8) along with seven known compounds (1, 2, and 9-13) were isolated from the leaves of M. pteleifolia. Their chemical structures were confirmed by extensive spectroscopic analysis including NMR, IR, ECD, and HRMS. All compounds isolated from the leaves of M. pteleifolia (1-13) have a phloroacetophenone skeleton. Notably, the new compound 8 contains an additional cyclobutane moiety in its structure. The bioactivities of the isolated compounds were evaluated, and compounds 1, 6, and 7 inhibited tumor necrosis factor-α-induced prostaglandin E2. Moreover, the major constituent, 3,5-di-C-β-d-glucopyranosyl phloroacetophenone (1), was found to be responsible for the antipyretic activity of M. pteleifolia based on in vivo experiments.
  18. Grismer LL, Wood PL, Lee CH, Quah ES, Anuar S, Ngadi E, et al.
    Zootaxa, 2015 Apr 20;3948(1):1-23.
    PMID: 25947760 DOI: 10.11646/zootaxa.3948.1.1
    An integrative taxonomic analysis is used to identify and describe two new species of the agamid genus Bronchocela (Kuhl) from Peninsular Malaysia: an upland species B. shenlong sp. nov. from Bukit Larut, Perak in the Bintang Mountain Range and Parit Falls, Cameron Highlands, Pahang in the Titiwangsa Mountain Range and an insular species, B. rayaensis sp. nov., from Pulau Langkawi, Kedah off the northwest coast on the border with Thailand. Both species are diagnosed from each other and all other species of Bronchocela on the basis of body shape, scale morphology, and color pattern. The analysis also demonstrates the remarkable genetic similarity of B. cristatella (Kuhl) throughout 1120 km of its range from northern Peninsular Malaysia to western Borneo despite its highly variable coloration and pattern. The two new species are appended to a rapidly growing list of newly described lizard species (60 to date) from Peninsular Malaysia tallied within the last decade.
  19. Lee CH, Ko AM, Yen CF, Chu KS, Gao YJ, Warnakulasuriya S, et al.
    Br J Psychiatry, 2012 Nov;201(5):383-91.
    PMID: 22995631 DOI: 10.1192/bjp.bp.111.107961
    Despite gradual understanding of the multidimensional health consequences of betel-quid chewing, information on the effects of dependent use is scant.
  20. Chan MY, Tan K, Tan HC, Huan PT, Li B, Phua QH, et al.
    Pharmacogenomics, 2012 Apr;13(5):533-42.
    PMID: 22462746 DOI: 10.2217/pgs.12.24
    AIM, MATERIALS & METHODS: We investigated the functional significance of CYP2C19*2, *3, *17 and PON1 Q192R SNPs in 89 consecutive Asian patients on clopidogrel treatment and the prevalence of functionally significant polymorphisms among 300 Chinese, Malays and Asian Indians.
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