Displaying publications 101 - 120 of 652 in total

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  1. Ang HH, Lee KL, Kiyoshi M
    J Basic Clin Physiol Pharmacol, 2004;15(3-4):303-9.
    PMID: 15803965 DOI: 10.1515/jbcpp.2004.15.3-4.303
    Eurycoma longifolia Jack commonly known as Tongkat Ali in Malaysia, has been used in Malaysia to increase male virility and sexual prowess. The objective of this study is to evaluate sexual arousal in sexually sluggish old male rats, 24 months old and retired breeders, receiving 200, 400, or 800 mg/kg of various fractions of E. longifolia Jack, twice daily, for 10 days. Control rats received 3 ml/kg of normal saline. The aphrodisiac effect was monitored by the act of yawning and stretching because yawning, either alone or associated with stretching, is considered an ancestral vestige surviving throughout evolution that promotes sexual arousal. The results showed that 800 mg/kg of E. longifolia Jack increased yawning by 50% and stretching by 16.7% in sexually sluggish old male rats, by 676-719% and 31-336%, respectively, in sexually active male rats, and by 22-44% and 75-100%, respectively, in middle aged, 9 months old and retired breeders. We conclude that the results of this study support the folk use of this plant as an aphrodisiac.
  2. Ang HH, Cheang HS, Yusof AP
    Exp Anim, 2000 Jan;49(1):35-8.
    PMID: 10803359 DOI: 10.1538/expanim.49.35
    We studied the effects of Eurycoma longifolia Jack, commonly known as Tongkat Ali in Malaysia, on the initiation of sexual performance and the weights of sexual accessories in inexperienced castrated male rats. The doses of 200, 400 and 800 mg/kg body weight, which were extracted from E. longifolia Jack, were orally administered to the rats twice daily for 10 days prior to the tests and continued throughout the test period. Testosterone was used as a positive control after injecting 15 mg/kg daily subcutaneously for 32 days. Results showed that E. longifolia Jack produced a dose-dependent increase in sexual performance of the treated animals, but the E. longifolia Jack groups showed lower sexual performance in mounting, intromission and ejaculation than the testosterone group. Further results also showed that E. longifolia Jack promoted the growth of both ventral prostate and seminal vesicles as compared with the control, but the growth of sexual accessories at 800 mg/kg of butanol, methanol, water and chloroform fractions of E. longifolia Jack was less than that of testosterone treated group. The present study therefore gives further evidence of the folkuse of E. longifolia as an aphrodisiac.
  3. Ang HH, Ikeda S, Gan EK
    Phytother Res, 2001 Aug;15(5):435-6.
    PMID: 11507738 DOI: 10.1002/ptr.968
    The butanol, methanol, water and chloroform extracts of the roots of Eurycoma longifolia Jack were studied using various tests of potency of treated male rats. The results showed that E. longifolia produced a dose-dependent, recurrent and significant increase in the episodes of penile reflexes as evidenced by increases in quick flips, long flips and erections of the treated male rats during the 30 min observation period. These results provide further evidence that E. longifolia increases the aphrodisiac potency activity in treated animals.
  4. Ang HH, Chan KL, Mak JW
    J Ethnopharmacol, 1995 Dec 15;49(3):171-5.
    PMID: 8824743 DOI: 0.1016/0378-8741(95)01321-0
    Six Malaysian chloroquine-resistant Plasmodium falciparum isolates were cultured in vitro following the candle-jar method. Antimalarial evaluations of daily replacement of culture medium containing chloroquine and a semi-purified extract of Eurycoma longifolia Jack (containing 13 beta, 18-dihydroeurycomanol (1), eurycomanol-2-O-beta-D-glucopyranoside (2), eurycomanol (3) and eurycomanone (4)) were performed on 6-well plates at 37 degrees C for a week. Presence or absence of the parasites was determined microscopically on thin-film Giemsa-stained preparations. Results showed that the antimalarial activity of Eurycoma longifolia Jack was dose-dependent and reached a maximum of < 50% at 0.07-5.00 micrograms ml-1 after 1 day post-treatment. However, complete inhibitions were observed at 1.25-5.00 micrograms ml-1 extract after 3 days post-treatment and 0.62 and 0.31 micrograms ml-1 after 4 and 6 days post-treatment, respectively. Further results indicated that chloroquine exhibited total inhibition at concentrations > 2.50 and 0.62 micrograms ml-1 after 1 and 2 days post-treatment, respectively and at all concentrations after 3 days post-treatment.
  5. Ang HH, Lee KL, Kiyoshi M
    Int J Toxicol, 2005 May-Jun;24(3):165-71.
    PMID: 16040569 DOI: 10.1080/10915810590952942
    The DCA (Drug Control Authority) of Malaysia implemented the phase 3 registration of traditional medicines on 1 January 1992. As such, a total of 100 products in various pharmaceutical dosage forms of a herbal preparation containing Smilax luzonensis, either single or combined preparations, were analyzed for the presence of lead, using atomic absorption spectrophotometry. Results showed that 14% of the above products possessed 10.02 to 21.21 ppm of lead, and, therefore, they failed to comply with the quality requirement for traditional medicines in Malaysia ( <10 ppm). Although this study showed that 86% of the products complied with the quality requirement for traditional medicines in Malaysia pertaining to lead, they cannot be assumed safe from lead contamination because of batch-to-batch inconsistency.
  6. Ang HH, Lee EL, Cheang HS
    Int J Toxicol, 2004 Jan-Feb;23(1):65-71.
    PMID: 15162849 DOI: 10.1080/10915810490269654
    The DCA (Drug Control Authority), Malaysia, has implemented the phase 3 registration of traditional medicines on 1 January 1992, with special emphasis on the quality, efficacy, and safety (including the presence of heavy metals) in all pharmaceutical dosage forms of traditional medicine preparations. As such, a total of 100 products in various pharmaceutical dosage forms of a herbal preparation, containing Tongkat Ali, were analyzed for mercury content using cold vapor atomic absorption spectrophotometer. Results showed that 36% of the above products possessed 0.52 to 5.30 ppm of mercury and, therefore, do not comply with the quality requirement for traditional medicines in Malaysia. Out of these 36 products, 5 products that possessed 1.05 to 4.41 ppm of mercury were in fact have already registered with the DCA, Malaysia. However, the rest of the products that contain 0.52 to 5.30 ppm of mercury still have not registered with the DCA, Malaysia. Although this study showed that only 64% of the products complied with the quality requirement for traditional medicines in Malaysia pertaining to mercury, they cannot be assumed safe from mercury contamination because of batch-to-batch inconsistency.
  7. Ang CK, Mohidin N, Chung KM
    Curr Eye Res, 2014 Sep;39(9):879-84.
    PMID: 25014251 DOI: 10.3109/02713683.2013.859273
    PURPOSE/AIM: Wink glass (WG), an invention to stimulate blinking at interval of 5 s was designed to reduce dry eye symptoms during visual display unit (VDU) use. The objective of this study is to investigate the effect of WG on visual functions that include blink rate, ocular surface symptoms (OSS) and tear stability during VDU use.
    MATERIALS AND METHODS: A total of 26 young and asymptomatic subjects were instructed to read articles in Malay language with a computer for 20 min with WG whereby their blink rate, pre- and post-task tear break-up time, and OSS were recorded. The results were compared to another reading session of the subjects wearing a transparent plastic sheet as a control.
    RESULTS: Non-invasive tear break-up time was reduced after reading session with transparent plastic sheet (pre-task = 5.97 s, post-task = 5.14 s, z = -2.426, p = 0.015, Wilcoxon), but remained stable (pre-task = 5.62 s, post-task = 5.35 s, z = -0.67, p = 0.501) during the reading session with WG. The blink rate recorded during reading session with plastic sheet was 9 blinks/min (median) and this increased to 15 blinks/min (z = -3.315, p = 0.001) with WG. The reading task caused OSS (maximum scores = 20) with median score of 1 (0-8) reduced to median score of 0 (0-3) after wearing WG (z = -2.417, p = 0.016).
    CONCLUSION: WG was found to increase post-task tear stability, increased blinking rate and reduced OSS during video display unit use among young and healthy adults. Although it may be considered as an option to improve dry eye symptoms among VDU users, further studies are warranted to establish its stability and its effect on subjects with dry eyes.
    KEYWORDS: Blink rate; Wink glass; non-invasive tear break-up time; visual display units
  8. Ang KP, Chan PF, Hamid RA
    J Biol Inorg Chem, 2021 10;26(7):833-853.
    PMID: 34476610 DOI: 10.1007/s00775-021-01892-6
    Tricyclohexylphosphanegold(I) n-mercaptobenzoate (n = 2, 3, 4) labelled as 1-3 were previously reported to significantly suppress thioredoxin reductase (TrxR) activities towards ovarian cancer cells, A2780, in vitro. Herein, we explored the role of 1-3 for their apoptosis inducing ability against A2780 cells. 1-3 exhibited IC50 values at 1.19 ± 0.03 µM, 2.28 ± 0.04 μM and 0.78 ± 0.01 μM, respectively, compared to cisplatin at 26.8 ± 0.15 µM. The compounds induced A2780 apoptosis via a caspase-dependent mitochondrion pathway as evidenced by ROS production, cytochrome c release, caspases-3/7, -8, -9 and -10 activation, APAF1 and BAX upregulation as well as BCL2A1 and BCL2 genes' downregulation. In addition, the death mode of 1-3 was also mediated via death receptor extrinsic pathway manifested by FAS, FASL, FADD, and TNFR1 genes' upregulation via Human Rt PCR analysis. In addition, 1-3 significantly caused A2780 arrest at S phase, which was associated with the upregulation of TP53, E2F1, RB1 and CDKN1A upregulation and downregulation of CDK1, CDK4, CDC25A and CDC25C genes. Based on these promising results, these phosphanegold(I) thiolate derivatives could act as feasible candidates for further advanced in vivo ovarian cancer studies to develop novel chemotherapeutic agents derived from metal-based agents.
  9. See BT, Yip KX, Ang HL
    Paediatr Int Child Health, 2018 02;38(1):76-79.
    PMID: 28222654 DOI: 10.1080/20469047.2017.1289312
    Haemophagocytic lymphohistiocytosis (HLH) is rare. Although Kawasaki disease (KD) has been reported as a precursor to HLH, coronary arteritis occurring at the onset of secondary HLH, not in association with KD, has not been reported. An 8-year-old girl presented with virus-induced secondary HLH associated with a giant aneurysm and ectasia of the coronary arteries which was detected incidentally at onset of the disease. She did not fulfill the criteria for diagnosis of KD. The coronary lesions improved after 6 months of treatment with dexamethasone and etoposide. Echocardiography early in the course of HLH is a useful tool to detect the unusual finding of coronary arteritis which may carry significant clinical sequelae.
  10. Ang PS, Yeo SL, Koran L
    Dementia (London), 2023 Apr;22(3):628-645.
    PMID: 36764831 DOI: 10.1177/14713012231155979
    INTRODUCTION: This study examines the underlying visual communication strategies found in existing images of dementia in the public domain. By delineating how experiences of dementia are visualized and their consequent social interpretations, we aim to inform and advocate for a dementia-inclusive visual communication, that is, visual depictions that cultivate and represent a dementia-inclusive society.

    METHODS: The visuals were analyzed by employing the Visual Discourses of Disability (ViDD) framework that juxtaposes the "perspectivizing-personizing" cline with the "enabling-disabling" continuum. The data studied comprise a total of 432 images sourced from three domains, namely (1) The Star, a Malaysian mainstream English newspaper (2012-2021); (2) Alzheimer's Disease Foundation Malaysia (ADFM) website (2019-2021); and (3) the Ministry of Health Malaysia (2019-2021) website. Findings from the visual analyses were corroborated by four representatives of ADFM in a group interview.

    RESULTS: There is a predominance of stigmatized images, constructing dementia as a loss and deficit, thus depicting individuals in distanced suffering. Generic representations of people through stock images, a unique focus on the hands, representations of brain degeneration through abstractions and missing puzzle pieces are also prevalent. Despite these, the interview data confirmed that the perspectivizing aspect may be necessary to educate the public on what dementia entails. While personizing images that depict personhood and actual persons living with dementia are ideal, the use of stock images may be necessary if there is a need to maintain confidentiality and observe sensitivities. Similarly, images with positive emotions are encouraged but disabling ones are equally important to reflect reality and inculcate empathy.

    CONCLUSION: When capturing, selecting and publishing images of dementia, organizations should deliberate on different visual elements which evoke empowerment, advocacy, handicapping and othering implications as outlined in the ViDD framework. Any decision should only be made after considering the purposes of publications and implications such images have on the intended audiences.

  11. Tobuse AJ, Ang CW, Yeong KY
    Life Sci, 2022 Aug 01;302:120660.
    PMID: 35642852 DOI: 10.1016/j.lfs.2022.120660
    With the continuous evolution of bacteria, the global antimicrobial resistance health threat is causing millions of deaths yearly. While depending on antibiotics as a primary treatment has its merits, there are no effective alternatives thus far in the pharmaceutical market against some drug-resistant bacteria. In recent years, vaccinology has become a key topic in scientific research. Combining with the growth of technology, vaccine research is seeing a new light where the process is made faster and more efficient. Although less discussed, bacterial vaccine is a feasible strategy to combat antimicrobial resistance. Some vaccines have shown promising results with good efficacy against numerous multidrug-resistant strains of bacteria. In this review, we aim to discuss the findings from studies utilizing reverse vaccinology for vaccine development against some multidrug-resistant bacteria, as well as provide a summary of multi-year bacterial vaccine studies in clinical trials. The advantages of reverse vaccinology in the generation of new bacterial vaccines are also highlighted. Meanwhile, the limitations and future prospects of bacterial vaccine concludes this review.
  12. Ang SS, Thoo YY, Siow LF
    Food Bioproc Tech, 2023 Jun 13.
    PMID: 37363383 DOI: 10.1007/s11947-023-03140-y
    Despite the multiple health benefits, natural flavonoid apigenin has poor aqueous solubility that restricts its delivery in foods. This study investigated the potential of spray-dried chitosan-coated liposomes prepared from scalable methods for the food industry as the delivery carriers for apigenin. Apigenin-loaded small unilamellar liposomes produced from ethanol injection had an encapsulation efficiency of 74.88 ± 5.31%. They were electrostatically stabilised via chitosan coating (0.25% w/v) and spray-dried. Spray-dried chitosan-coated apigenin liposomes (SCAL) exhibited the following powder characteristics: yield 66.62 ± 3.08%, moisture content 4.33 ± 0.56%, water activity 0.2242 ± 0.0548, particle size 10.97 ± 1.55 μm, nearly spherical morphology with wrinkles and dents under microscopic observation. Compared with the unencapsulated apigenin, SCAL demonstrated improved aqueous solubility (10.22 ± 0.18 mg/L), higher antioxidant capacity, and stability against simulated gastrointestinal digestion. The chitosan coating gave a slower in-vitro release of apigenin in SCAL (77.0 ± 6.2%) than that of uncoated apigenin liposomes (94.0 ± 5.3%) at 12 h. The apigenin release kinetics from SCAL could be represented by the Korsmeyer-Peppas model (R2 = 0.971). These findings suggest that SCAL could be a promising delivery system of apigenin for functional food applications.
  13. Ang WS, Jamil TR, Kamaludin R, Mustafar R
    Med J Malaysia, 2023 Nov;78(6):721-732.
    PMID: 38031213
    INTRODUCTION: Chronic kidney disease (CKD) rapid progression is associated with higher risk of end-stage kidney disease and higher mortality rate. Monitoring and recognition of CKD rapid progression is still lacking, however interventions have been shown to improve this. Thus, this study aimed to evaluate the acceptability and feasibility of CKD-CHECK toolkit and preliminary measure the outcome of the CKD-CHECK toolkit in assisting primary care doctor to order further tests for CKD rapid progressors and trigger appropriate nephrology referral.

    MATERIALS AND METHODS: The CKD-CHECK (CKD-CHECK EGFR Chart in Kidney disease) is a toolkit that was developed to auto-generate patients' eGFR trend using a line graph, displaying the trend visually over a year. It identifies patients with rapid CKD progression, triggers the doctors to order appropriate tests (proteinuria quantification or renal imaging) and helps in decision making (continued monitoring at primary care level or referral to nephrologist). The toolkit was piloted among medical officers practising in a hospital-based primary care clinic treating patients with eGFR<60ml/min/1.73m2 using an interventional before-after study design from February to May 2022. In the preintervention period, the CKD patients were managed based on standard practice. The doctors then used the CKDCHECK toolkit on the same group of CKD patients during the intervention period. The feasibility and acceptability of the toolkit was assessed at the end of the study period using the Acceptability of Intervention Measure (AIM) and Feasibility of Intervention Measure (FIM) questionnaires. All patients' clinical data and referral rate were collected retrospectively through medical files and electronic data systems. Comparison between the pre- and post-intervention group were analysed using paired t-test and McNemar test, with statistical significance p value of <0.05.

    RESULTS: A total of 25 medical officers used the toolkit on 60 CKD patients. The medical officers found the CKD-CHECK toolkit to be highly acceptable and feasible in primary care setting. The baseline characteristics of the patients were a mean age of 72 years old, predominantly females and Chinese ethnicity. Majority of the CKD patients had diabetes mellitus, hypertension and dyslipidemia. The numbers of CKD rapid progressors was similar (26.7% in the preintervention group vs 33.3% in the post-intervention group). There were no significant differences in terms of proteinuria assessment and ultrasound kidney for CKD rapid progressors before and after the intervention. However, a significant number of CKD rapid progressors were referred to nephrologists after the use of CKD-CHECK toolkit (p=0.016).

    CONCLUSIONS: CKD-CHECK toolkit is acceptable and feasible to be used in primary care. Preliminary findings show that the CKD-CHECK toolkit improved the primary care doctor's referral of rapid CKD progressors to nephrologists.

  14. Boo NY, Lee Ang EL, The Malaysian National Neonatal Registry
    Malays J Pathol, 2023 Dec;45(3):441-456.
    PMID: 38155385
    BACKGROUND: Information on incidence and risk factors associated with different types of neonatal pneumothorax were lacking globally.

    OBJECTIVES: To determine incidences of pneumothorax developed spontaneously and during different modes of respiratory support, and risk factors associated with each type of pneumothorax.

    STUDY DESIGN: Retrospective observational study of neonates in the Malaysian National Neonatal Registry.

    SETTING: 44 Malaysian neonatal intensive care units (NICUs).

    PARTICIPANTS: All neonates born in 2015-2020 and admitted to NICUs.

    RESULTS: Pneumothorax developed in 3265 neonates: 37.5% occurred spontaneously, 62.5% during respiratory support. The incidence of all types of pneumothorax was 1.75 per 1000 livebirths, and of spontaneous pneumothorax was 0.58 per 1000 livebirths. Pneumothorax developed in 0.6% (450/70512) of neonates during continuous positive air way pressure therapy (nCPAPt), 1.8% (990/54994) of neonates during conventional mechanical ventilation (CMV), and 7.0% (599/8557) of neonates during high frequency ventilation (HFV). Term neonates had significantly higher pneumothorax rate than preterms (p<0.001). Multiple logistic regression analyses show that exposure to intermittent positive pressure ventilation and chest compression at birth were significant independent factors associated with increased risk of spontaneous pneumothorax and CMV, and persistent pulmonary hypertension was associated with increased risk of spontaneous pneumothorax and pneumothorax during CMV and HFV.

    CONCLUSIONS: The most common type of pneumothorax was spontaneous in-onset. Neonates on HFV had the highest and those on nCPAPt the lowest rate of pneumothorax. Improving training of resuscitation techniques at birth and strategies of use of invasive modes of respiratory support may reduce incidences of all types of pneumothorax.

  15. Chan PF, Ang KP, Hamid RA
    J Biol Inorg Chem, 2024 Feb 18.
    PMID: 38369679 DOI: 10.1007/s00775-023-02041-x
    We previously reported that the bismuth(III) dithiocarbamate derivative, bismuth diethyldithiocarbamate (1) exhibited greater cytotoxicity while inducing apoptosis via the intrinsic pathway in MCF-7 cells. We further evaluated the other bismuth(III) dithiocarbamate derivatives, Bi[S2CNR]3, with R = (CH2CH2OH)(iPr), (CH2)4, and (CH2CH2OH)(CH3), denoted as 2, 3, and 4, respectively, in the same MCF-7 cell line. 2-4 were found to exhibit IC50 values of 10.33 ± 0.06 µM, 1.07 ± 0.01 µM and 25.37 ± 0.12 µM, respectively, compared to that of cisplatin at 30.53 ± 0.23 µM. Apoptotic promotion via the mitochondrial-dependent pathway was due to the elevation of intracellular reactive oxygen species (ROS), promotion of caspases, release of cytochrome c, fragmentation of DNA, and results of staining assay observed in all compound-treated cells. 2-4 are also capable of suppressing MCF-7 cell invasion and modulate Lys-48 also Lys-63 linked polyubiquitination, leading to proteasomal degradation. Analysis of gene expression via qRT-PCR revealed their modulation, which supported all activities conducted upon treatment with 2-4. Altogether, bismuth dithiocarbamate derivatives, with bismuth(III) as the metal center bound to ligands, isopropyl ethanol, pyrrolidine, and methyl ethanol dithiocarbamate, are potential anti-breast cancer agents that induce apoptosis and suppress metastasis. Further studies using other breast cancer cell lines and in vivo studies are recommended to clarify the anticancer effects of these compounds.
  16. Ang BH, Teo SH, Ho WK
    PMID: 39018331 DOI: 10.1158/1055-9965.EPI-24-0005
    INTRODUCTION: Assessing breast cancer risks from lifestyle and reproductive factors is critical for developing population-specific risk prediction tools. However, limited studies have evaluated these risks in recent Asian birth cohorts.

    METHODS: We systematically reviewed articles published from January 2010 to December 2023, examining breast cancer risk factors in Asian women. Data were described narratively, estimates pooled, and prevalence and attributable proportions compared across Asian populations.

    RESULTS: Of the 128 studies reviewed, 103 reported adjusted effect sizes for meta-analysis. Lifestyle and reproductive factors were predictive of breast cancer risk in Asian women, with varying impacts on pre-menopausal and post-menopausal women. Relative risks were similar within Asian populations and in comparison to European populations, except for menarche, menopause, and hormone receptor therapy. However, risk factor distributions differed across populations. Whilst alcohol intake (21%) and oral contraceptive use (20%) emerged as the most attributable modifiable risk factors in Europeans, passive smoking (24%) and higher BMI (17%,≥24kg/m2 among post-menopausal women) were predominant in Asians.

    CONCLUSION: Our study shows that whilst the effects of lifestyle and reproductive breast cancer risk factors are largely similar across different populations, their distributions vary.

    IMPACT: Our analysis underscores the importance of considering population-specific risk factor distributions when developing risk prediction tools for Asian populations.

  17. Nadarajan VS, Ang CH, Bee PC
    Eur J Haematol, 2012 Feb;88(2):175-8.
    PMID: 21950422 DOI: 10.1111/j.1600-0609.2011.01712.x
    We investigated the role of lipocalin-2 (LCN-2) and its receptor (SLC22A17) in mediating clonal dominance in a patient with both BCR-ABL and JAK2-V617F mutations. LCN-2 mRNA showed a near 50-fold increase in expression, accompanied by down-regulation of SLC22A17, coinciding with increase in BCR-ABL transcripts, loss of JAK2-V617F and change of clinical phenotype from polycythaemia vera to chronic myeloid leukaemia. These changes were reversed after commencing imatinib mesylate. Consistent with experimental studies, BCR-ABL+ cells express LCN-2 leading to suppression of BCR-ABL- cells and explain their eventual dominance when occurring together with JAK2-V617F.
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