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Properties of a cyclic 3'5'-nucleotide phosphodiesterase from Vigna mungo

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.
Fulltext An assessment of Stuart's transport medium in the diagnosis of gonorrhoea

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.
Torsion of ovarian tumors: a clinicopathological study

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.
Fulltext Primary breast tuberculosis (TB) in a patient with known invasive breast carcinoma: A case report

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.
Fulltext Importance of Interfacial Adhesion Condition on Characterization of Plant-Fiber-Reinforced Polymer Composites: A Review

Lee CH, Khalina A, Lee SH

Polymers (Basel), 2021 Jan 29;13(3).
PMID: 33573036 DOI: 10.3390/polym13030438

Plant fibers have become a highly sought-after material in the recent days as a result of raising environmental awareness and the realization of harmful effects imposed by synthetic fibers. Natural plant fibers have been widely used as fillers in fabricating plant-fibers-reinforced polymer composites. However, owing to the completely opposite nature of the plant fibers and polymer matrix, treatment is often required to enhance the compatibility between these two materials. Interfacial adhesion mechanisms are among the most influential yet seldom discussed factors that affect the physical, mechanical, and thermal properties of the plant-fibers-reinforced polymer composites. Therefore, this review paper expounds the importance of interfacial adhesion condition on the properties of plant-fiber-reinforced polymer composites. The advantages and disadvantages of natural plant fibers are discussed. Four important interface mechanism, namely interdiffusion, electrostatic adhesion, chemical adhesion, and mechanical interlocking are highlighted. In addition, quantifying and analysis techniques of interfacial adhesion condition is demonstrated. Lastly, the importance of interfacial adhesion condition on the performances of the plant fiber polymer composites performances is discussed. It can be seen that the physical and thermal properties as well as flexural strength of the composites are highly dependent on the interfacial adhesion condition.
Review on pharmacological activities of Cinnamomum subavenium

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.
Detection of Chlamydia trachomatis in urine samples by polymerase chain reaction and enzyme immunoassay

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.
Perceived Social Support and Life Satisfaction of Malaysian Chinese Young Adults: The Mediating Effect of Loneliness

Gan SW, Ong LS, Lee CH, Lin YS

J Genet Psychol, 2020 08 13;181(6):458-469.
PMID: 32787705 DOI: 10.1080/00221325.2020.1803196

This paper examined the role of loneliness in mediating the relation between social support and life satisfaction among Chinese young adults within the Malaysian context. Young adults (N = 275; Mage = 22.41; SD = 1.76; 57.5% females) completed self-administered questionnaires on the scales of perceived social support, loneliness and life satisfaction. The results of Structural Equation Modeling (SEM) showed a partial mediation effect of loneliness on the relation between social support and life satisfaction. The integration of the bottom-up theory of subjective well-being and social cognitive theory is included to explain the mediating process. The results revealed that perceived social support can relate to a lower level of loneliness, which could eventually lead to higher levels of young adults' life satisfaction. Overall, the findings highlighted the importance of social support as well as their loneliness as a mediating pathway in promoting Malaysian Chinese young adults' life satisfaction. Interventions are also suggested to optimize life satisfaction as a whole.
Melt volume flow rate and melt flow rate of kenaf fibre reinforced Floreon/magnesium hydroxide biocomposites

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.
Fulltext Ectopic Papillary Thyroid Carcinoma of the Posterior Pharynx

Lee CH, Hayati F, Azizan N, Sharif SZ

Iran J Otorhinolaryngol, 2023 Nov;35(131):325-328.
PMID: 38074483 DOI: 10.22038/IJORL.2023.73099.3471

INTRODUCTION: Ectopic thyroid is an uncommon condition resulting from the aberrant development of the normal thyroid gland and is usually found along the thyroglossal tract: lingual, submandibular, thyroglossal cysts, intra-tracheal and mediastinal, or, on rare occasions, in the adrenal gland, gallbladder, gastrointestinal tract, pancreas, and struma ovarii.
CASE REPORTS: We describe a novel case where primary papillary thyroid carcinoma (PTC) was found after a trans-oral excision of a tumor containing ectopic thyroid tissue at the posterior pharynx, an area not known to be a location for ectopic thyroid. Delays due to the COVID-19 pandemic resulted in regional cervical metastases and multifocal PTC. The female patient successfully underwent total thyroidectomy, selective cervical and central lymph node dissection, followed by adjuvant radioactive iodine ablation, with no evidence of distant metastases.
CONCLUSIONS: Ectopic thyroid tissue is uncommon and may be in the posterior pharynx. The principles of management remain those of differentiated thyroid malignancy: complete surgical resection of any tumor focus, total thyroidectomy, and node dissection of involved lymph nodes, followed by adjuvant radioactive iodine in iodine-sensitive tumors.
Outcomes of Malaysian patients with advanced lung adenocarcinoma and unknown epidermal growth factor receptor mutation status treated with gefitinib

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.
Successful pregnancy with epidermal growth factor receptor tyrosine kinase inhibitor treatment of metastatic lung adenocarcinoma presenting with respiratory failure

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.
An improved enzyme assay for molybdenum-reducing activity in bacteria

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.
Fulltext Technologies for Assessment of Motor Disorders in Parkinson's Disease: A Review

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.
Fulltext Diagnostic challenge in diagnosing bilateral breast metastases from mediastinal neuroendocrine tumor: A case report

Chan KH, Lee CH, Sharif SZ, Hayati F, Sallapan S

Ann Med Surg (Lond), 2020 Dec;60:438-441.
PMID: 33251002 DOI: 10.1016/j.amsu.2020.11.035

Background: Metastatic neuroendocrine tumours (NETs) to the breast are very rare entities.
Case presentation: A 26-year-old lady presented with anterior neck swelling with symptoms of superior vena cava syndrome for 6 months. Imaging study revealed a mediastinal mass which was preceded with core biopsy which was consistent with high-grade small cell NETs. Despite second-line adjuvant chemotherapy and radiotherapy, her disease became advanced which was confirmed via restaging scan. There were bilateral breast lesions discovered during the scan which was deemed to be metastatic NETs histologically. Despite prompt initiation of treatment, she succumbed 1 year after the radiotherapy due to disease progression.
Conclusion: High suspicion of an index is needed for diagnosis when patients with known primary NETs present with suspicious breast lesions. Triple assessment is mandatory, however histopathology assessment and immunohistochemistry staining are the mainstay of diagnosis.
Fulltext Academic procrastination and self-efficacy among a group of dental undergraduate students in Malaysia

Uma E, Lee CH, Shapiai SNHBM, Binti Mat Nor AN, Soe HHK, Varghese E

J Educ Health Promot, 2020;9:326.
PMID: 33426130 DOI: 10.4103/jehp.jehp_195_20

BACKGROUND: Undergraduate dental students have to do multiple tasks as part of their extensive curriculum in order to achieve the proficiencies expected of them. During the course of their study, a tendency to procrastinate and question their self-efficacy is detrimental for the students. The aim of this study was to evaluate the level of procrastination and self-efficacy and its related factors among dental undergraduate students.
SUBJECTS AND METHODS: This cross-sectional study was conducted among all (n = 361) consented dental undergraduate students of our dental school. A twenty-item Lay's Procrastination Scale for student population and a ten-item General Self-Efficacy Scale were used for the study after getting institutional ethical approval. The quantitative data were explained using descriptive statistics. Independent sample t-test and ANOVA were used to determine the association between self-efficacy, academic procrastination, and genders and academic years. Pearson correlation coefficient was used to determine the association between self-efficacy and procrastination. Multiple linear regression analysis was performed to determine the related factors to academic procrastination.
RESULTS: High procrastination (score ≥62) was seen among 28.5% of students. The mean self-efficacy score was 29.5. There was no significant difference between genders for procrastination scores (P = 0.835) and between academic years (P = 0.226). Males showed significantly more self-efficacy (P < 0.001), and self-efficacy did not show any significant difference (P = 0.204) between academic years though a tendency for year 5 students to have lower self-efficacy scores was observed. Academic procrastination was negatively correlated with self-efficacy (r = -0.238 and P < 0.001).
CONCLUSIONS: For dental undergraduates who have cognitive load as well as work associated with patients, procrastination and self-efficacy are negatively correlated.
Edible Bird's Nest: The Functional Values of the Prized Animal-Based Bioproduct From Southeast Asia-A Review

Lee TH, Wani WA, Lee CH, Cheng KK, Shreaz S, Wong S, et al.

Front Pharmacol, 2021;12:626233.
PMID: 33953670 DOI: 10.3389/fphar.2021.626233

Edible Bird's Nest (EBN) is the most prized health delicacy among the Chinese population in the world. Although some scientific characterization and its bioactivities have been studied and researched, no lights have been shed on its actual composition or mechanism. The aim of this review paper is to address the advances of EBN as a therapeutic animal bioproduct, challenges and future perspectives of research involving EBN. The methodology of this review primarily involved a thorough search from the literature undertaken on Web of Science (WoS) using the keyword "edible bird nest". Other information were obtained from the field/market in Malaysia, one of the largest EBN-producing countries. This article collects and describes the publications related to EBN and its therapeutic with diverse functional values. EBN extracts display anti-aging effects, inhibition of influenza virus infection, alternative traditional medicine in athletes and cancer patients, corneal wound healing effects, stimulation of proliferation of human adipose-derived stem cells, potentiate of mitogenic response, epidermal growth factor-like activities, enhancement of bone strength and dermal thickness, eye care, neuroprotective and antioxidant effects. In-depth literature study based on scientific findings were carried out on EBN and its properties. More importantly, the future direction of EBN in research and development as health-promoting ingredients in food and the potential treatment of certain diseases have been outlined.
Fulltext Mechanical Strength, Thermal Conductivity and Electrical Breakdown of Kenaf Core Fiber/Lignin/Polypropylene Biocomposite

Ahmad Saffian H, Talib MA, Lee SH, Md Tahir P, Lee CH, Ariffin H, et al.

Polymers (Basel), 2020 Aug 15;12(8).
PMID: 32824275 DOI: 10.3390/polym12081833

Mechanical strength, thermal conductivity and electrical breakdown of polypropylene/lignin/kenaf core fiber (PP/L/KCF) composite were studied. PP/L, PP/KCF and PP/L/KCF composites with different fiber and lignin loading was prepared using a compounding process. Pure PP was served as control. The results revealed that tensile and flexural properties of the PP/L/KCF was retained after addition of lignin and kenaf core fibers. Thermal stability of the PP composites improved compared to pure PP polymer. As for thermal conductivity, no significant difference was observed between PP composites and pure PP. However, PP/L/KCF composite has higher thermal diffusivity. All the PP composites produced are good insulating materials that are suitable for building. All PP composites passed withstand voltage test in air and oil state as stipulated in IEC 60641-3 except PP/L in oil state. SEM micrograph showed that better interaction and adhesion between polymer matrix, lignin and kenaf core fibers was observed and reflected on the better tensile strength recorded in PP/L/KCF composite. This study has successfully filled the gap of knowledge on using lignin and kenaf fibers as PP insulator composite materials. Therefore, it can be concluded that PP/Lignin/KCF has high potential as an insulating material.
Microplastics and nanoplastics in global food webs: A bibliometric analysis (2009-2019)

Wong SL, Nyakuma BB, Wong KY, Lee CT, Lee TH, Lee CH

Mar Pollut Bull, 2020 Sep;158:111432.
PMID: 32753215 DOI: 10.1016/j.marpolbul.2020.111432

This paper presents the research landscape on microplastics and nanoplastics (M/NPs) in global food webs based on a bibliometric analysis of 330 publications published in 2009-2019 extracted from Web of Science. The publications increased tremendously since 2013. Marine Pollution Bulletin is one of the top productive journals for this topic. The publication landscape related to M/NPs in global food webs, as interdisciplinary research, is highly dependent on the funding availability. The high productivities of England, China, USA and European countries are attributed to the funding from the agencies at regional or national levels. Keyword analysis reveals the shift of research hotspots from investigations on M/NPs absorbed by various organisms in the ecosystems to studies on the trophic transfer of M/NPs and sorbed contaminants in the food webs and their associated adverse impacts. Funding agencies play important roles in leading the future development of this topic.
Fulltext Effect of Empty Fruit Brunch reinforcement in PolyButylene-Succinate/Modified Tapioca Starch blend for Agricultural Mulch Films

Ayu RS, Khalina A, Harmaen AS, Zaman K, Mohd Nurrazi N, Isma T, et al.

Sci Rep, 2020 01 24;10(1):1166.
PMID: 31980742 DOI: 10.1038/s41598-020-58278-y

In this study, it focused on empty fruit brunch (EFB) fibres reinforcement in polybutylene succinate (PBS) with modified tapioca starch by using hot press technique for the use of agricultural mulch film. Mechanical, morphological and thermal properties were studied. Mechanical analysis showed decreased in values of modulus strength for both tensile and flexural testing for fibres insertion. Higher EFB fibre contents in films resulted lower mechanical properties due to poor fibre wetting from insufficient matrix. This has also found evident in SEM micrograph, showing poor interfacial bonding. Water vapour permeability (WVP) shows as higher hydrophilic EFB fibre reinforcement contents, the rate of WVP also increase. Besides this, little or no significant changes on thermal properties for composite films. This is because high thermal stability PBS polymer show its superior thermal properties dominantly. Even though EFB fibres insertion into PBS/tapioca starch biocomposite films have found lower mechanical properties. It successfully reduced the cost of mulch film production without significant changes of thermal performances.

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