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Fulltext Current perspectives on dengue episode in Malaysia

Pang EL, Loh HS

Asian Pac J Trop Med, 2016 Apr;9(4):395-401.
PMID: 27086160 DOI: 10.1016/j.apjtm.2016.03.004

Prevalence of dengue transmission has been alarmed by an estimate of 390 million infections per annum. Urban encroachment, ecological disruption and poor sanitation are all contributory factors of increased epidemiology. Complication however arises from the fact that dengue virus inherently exists as four different serotypes. Secondary infection is often manifested in the more severe form, such that antibody-dependent enhancement (ADE) could aggravate ailment by allowing pre-existing antibodies to form complexes with infecting viruses as means of intrusion. Consequently, increased viraemic titter and suppression of antiviral response are observed. Deep concerns are thus expressed in regards to escalating trend of hospitalisation and mortality rates. In Malaysia, situation is exacerbated by improper clinical management and pending vector control operations. As a preparedness strategy against the potential deadly dengue pandemic, the call for development of a durable and cost-effective dengue vaccine against all infecting serotypes is intensified. Even though several vaccine candidates are currently being evaluated in clinical trials, uncertainties in regards to serotypes interference, incomplete protection and dose adequacy have been raised. Instead of sole reliance on outsourcing, production of local vaccine should be considered in coherent to government's efforts to combat against dengue.
Fulltext Towards development of a universal dengue vaccine - How close are we?

Pang EL, Loh HS

Asian Pac J Trop Med, 2017 Mar;10(3):220-228.
PMID: 28442105 DOI: 10.1016/j.apjtm.2017.03.003

Dengue has been ranked as one of the top emerging diseases in Asia and Latin America. Current epidemiological data may not even reflect the true burden of disease due to under-reported figures. Vector control programmes have failed to contain the disease and worst of all, no specific treatment is available at the moment. Thereby, this pushes the demand for a dengue vaccine as a long-term protective approach. Despite there are numerous vaccine candidates ahead, they could be held back by different aspects in promoting vaccine implementation. Particularly for developing nations, logistics and cost are the major hurdles that need to be addressed in order to provide a quick yet affordable medical relief. As an alternative, plant-based vaccine production system is able to offer an attractive prospect given to its advantages of biocontainment warranty, low operation cost, rapid scalability and logistics flexibility. Researches that have embarked on this scope are laid out and reviewed in terms of the feasibility of plant system to serve as a biofactory for dengue vaccine.
A review on ethnobotany, pharmacology and phytochemistry of Tabernaemontana corymbosa

Abubakar IB, Loh HS

J Pharm Pharmacol, 2016 Apr;68(4):423-32.
PMID: 26887962 DOI: 10.1111/jphp.12523

OBJECTIVES: Tabernaemontana is a genus from the plant family, Apocynaceae with vast medicinal application and widespread distribution in the tropics and subtropics of Africa, Americas and Asia. The objective of this study is to critically evaluate the ethnobotany, medicinal uses, pharmacology and phytochemistry of the species, Tabernaemontana corymbosa (Roxb. ex Wall.) and provide information on the potential future application of alkaloids isolated from different parts of the plant.
KEY FINDINGS: T. corymbosa (Roxb. ex Wall.) parts are used as poultice, boiled juice, decoctions and infusions for treatment against ulceration, fracture, post-natal recovery, syphilis, fever, tumours and orchitis in Malaysia, China, Thailand and Bangladesh. Studies recorded alkaloids as the predominant phytochemicals in addition to phenols, saponins and sterols with vast bioactivities such as antimicrobial, analgesic, anthelmintic, vasorelaxation, antiviral and cytotoxicity.
SUMMARY: An evaluation of scientific data and traditional medicine revealed the medicinal uses of different parts of T. corymbosa (Roxb. ex Wall.) across Asia. Future studies exploring the structure-bioactivity relationship of alkaloids such as jerantinine and vincamajicine among others could potentially improve the future application towards reversing anticancer drug resistance.
Alkaloid extracts of Ficus species and palm oil-derived tocotrienols synergistically inhibit proliferation of human cancer cells

Abubakar IB, Lim KH, Loh HS

Nat Prod Res, 2015;29(22):2137-40.
PMID: 25515603 DOI: 10.1080/14786419.2014.991927

Tocotrienols have been reported to possess anticancer effects other than anti-inflammatory and antioxidant activities. This study explored the potential synergism of antiproliferative effects induced by individual alkaloid extracts of Ficus fistulosa, Ficus hispida and Ficus schwarzii combined with δ- and γ-tocotrienols against human brain glioblastoma (U87MG), lung adenocarcinoma (A549) and colorectal adenocarcinoma (HT-29) cells. Cell viability and morphological results demonstrated that extracts containing a mixture of alkaloids from the leaves and bark of F. schwarzii inhibited the proliferation of HT-29 cells, whereas the alkaloid extracts of F. fistulosa inhibited the proliferation of both U87MG and HT-29 cells and showed synergism in combined treatments with either δ- or γ-tocotrienol resulting in 2.2-34.7 fold of reduction in IC50 values of tocotrienols. The observed apoptotic cell characteristics in conjunction with the synergistic antiproliferative effects of Ficus species-derived alkaloids and tocotrienols assuredly warrant future investigations towards the development of a value-added chemotherapeutic regimen against cancers.
Development of a quantitative real-time RT-PCR for kinetic analysis of immediate-early transcripts of rat cytomegalovirus

Loh HS, Mohd-Azmi ML

Acta Virol., 2009;53(4):261-9.
PMID: 19941390

One-step real-time RT-PCR assay was developed for quantification of the immediate-early (IE), namely IE1 and IE2 transcripts of Rat cytomegalovirus (RCMV), strain ALL-03 in rat embryonic fibroblast cells (REF). This in-house SYBR Green I based RT-PCR was shown to have higher amplification efficiency and detection limit as compared to a commercially available real-time RT-PCR kit in quantifying these two transcripts. The quantification histogram revealed the divergence of transcription activities of the two IE genes. The IE1 transcript had a concentration peak at 7 hrs post infection (p.i.), whereas IE2 transcript at 20 hrs p.i. Regulation of IE expression is critical for determination, whether the infection is going to be abortive, lytic or latent. Therefore, this in-house developed quantitative RT-PCR assay offers an alternative for diagnosis and monitoring of the acute cytomegalovirus (CMV) infection directed at IE transcript detection.
The prevalence and correlates of alcohol use disorder amongst bipolar patients in a hospital setting, Malaysia

Yee HA, Loh HS, Ng CG

Int J Psychiatry Clin Pract, 2013 Oct;17(4):292-7.
PMID: 23170840 DOI: 10.3109/13651501.2012.752012

To determine the prevalence of alcohol-use disorder and associated correlates amongst bipolar patients in a university hospital in Malaysia.
Fulltext Synergistic Apoptotic Effects of Tocotrienol Isomers and Acalypha wilkesiana on A549 and U87MG Cancer Cells

Abubakar IB, Lim SW, Loh HS

Trop Life Sci Res, 2018 Mar;29(1):229-238.
PMID: 29644026 MyJurnal DOI: 10.21315/tlsr2018.29.1.15

Recent studies suggested that combined treatment approaches can be used to improve anticancer potency and circumvent the limitations of high-dose tocotrienols administration. Acalypha wilkesiana is a medicinal plant that has been used as an adjunct treatment for cancers in traditional medicine. Herein, the effects of single and combined treatments of β-, γ- and δ-tocotrienols and ethyl acetate extract (9EA) of Acalypha wilkesiana on lung (A549) and brain (U87MG) cancer cells were investigated. γ- and δ-tocotrienols exhibited higher potent antiproliferative effects against A549 (12.1 μg/ml and 13.6 μg/ml) and U87MG cells (3.3 μg/ml and 5.2 μg/ml) compared to β-tocotrienols (9.4 μg/ml and 92.4 μg/ml), respectively. Whereas, 9EA induced potent antiproliferative effects against U87MG cells only (2.0 μg/ml). Combined treatments of tocotrienols and 9EA induced a synergistic growth inhibition with up to 8.4-fold reduction in potent doses of β-, γ- and δ-tocotrienols on A549 cells. Apoptotic features were also evidenced on A549 cells receiving single and combined treatments. The synergism may greatly improve the therapeutic outcome for lung cancer.
In vitro evaluation of osteoblast adhesion, proliferation and differentiation on chitosan-TiO2nanotubes scaffolds with Ca2+ions

Lim SS, Chai CY, Loh HS

Mater Sci Eng C Mater Biol Appl, 2017 Jul 01;76:144-152.
PMID: 28482510 DOI: 10.1016/j.msec.2017.03.075

Hydrothermally synthesized TiO2nanotubes (TNTs) were first used as a filler for chitosan scaffold for reinforcement purpose. Chitosan-TNTs (CTNTs) scaffolds prepared via direct blending and freeze drying retained cylindrical structure and showed enhanced compressive modulus and reduced degradation rate compared to chitosan membrane which experienced severe shrinkage after rehydration with ethanol. Macroporous interconnectivity with pore size of 70-230μm and porosity of 88% were found in CTNTs scaffolds. Subsequently, the functionalization of CTNTs scaffolds with CaCl2solutions (0.5mM-40.5mM) was conducted at physiological pH. The adsorption isotherm of Ca2+ions onto CTNTs scaffolds fitted well with Freundlich isotherm. CTNTs scaffolds with Ca2+ions showed high biocompatibility by promoting adhesion, proliferation and early differentiation of MG63 in a non-dose dependent manner. CTNTs scaffolds with Ca2+ions can be an alternative for bone regeneration.
Bone health among patients with primary aldosteronism: a systematic review and meta-analysis

Loh HH, Yee A, Loh HS

Minerva Endocrinol., 2019 Dec;44(4):387-396.
PMID: 30482008 DOI: 10.23736/S0391-1977.18.02867-5

INTRODUCTION: Recent studies showed a possible association between hyperaldosteronism and secondary hyperparathyroidism leading to reduced bone health, however results are conflicting.
EVIDENCE ACQUISITION: We conducted a meta-analysis to evaluate the relationship between primary aldosteronism (PA) with bone biochemical markers and to assess bone mineral density in patients with primary aldosteronism.
EVIDENCE SYNTHESIS: A total of 939 subjects were examined (37.5% with PA). Patients with PA had significantly higher serum parathyroid hormone, lower serum calcium, higher urine calcium excretion and higher serum alkaline phosphatase compared to patients without PA, with no significant difference in serum vitamin D between both groups. Bone mineral density of lumbar spine, femoral neck and total neck of femur were similar between two groups. With PA treatment, there was a significant increment in serum calcium and reduction in serum parathyroid hormone.
CONCLUSIONS: PA is associated with hypercalciuria with subsequent secondary hyperparathyroidism. This potentially affects bone health. We recommend this to be part of complication screening among patients with PA.
Fulltext Using transgenic plants and modified plant viruses for the development of treatments for human diseases

Loh HS, Green BJ, Yusibov V

Curr Opin Virol, 2017 10;26:81-89.
PMID: 28800551 DOI: 10.1016/j.coviro.2017.07.019

Production of proteins in plants for human health applications has become an attractive strategy attributed by their potentials for low-cost production, increased safety due to the lack of human or animal pathogens, scalability and ability to produce complex proteins. A major milestone for plant-based protein production for use in human health was achieved when Protalix BioTherapeutics produced taliglucerase alfa (Elelyso®) in suspension cultures of a transgenic carrot cell line for the treatment of patients with Gaucher's disease, was approved by the USA Food and Drug Administration in 2012. In this review, we are highlighting various approaches for plant-based production of proteins and recent progress in the development of plant-made therapeutics and biologics for the prevention and treatment of human diseases.
Fulltext Protein profiling and histone deacetylation activities in somaclonal variants of oil palm (Elaeis guineensis Jacq.)

Yaacob JS, Loh HS, Mat Taha R

ScientificWorldJournal, 2013;2013:613635.
PMID: 23844406 DOI: 10.1155/2013/613635

Mantled fruits as a result of somaclonal variation are often observed from the oil palm plantlets regenerated via tissue culture. The mantling of fruits with finger-like and thick outer coating phenotypes significantly reduces the seed size and oil content, posing a threat to oil palm planters, and may jeopardize the economic growth of countries that depend particularly on oil palm plantation. The molecular aspects of the occurrence of somaclonal variations are yet to be known, possibly due to gene repression such as DNA methylation, histone methylation and histone deacetylation. Histone deacetylases (HDACs), involved in eukaryotic gene regulation by catalyzing the acetyl groups are removal from lysine residues on histone, hence transcriptionally repress gene expression. This paper described the total protein polymorphism profiles of somaclonal variants of oil palm and the effects of histone deacetylation on this phenomenon. Parallel to the different phenotypes, the protein polymorphism profiles of the mantled samples (leaves, fruits, and florets) and the phenotypically normal samples were proven to be different. Higher HDAC activity was found in mantled leaf samples than in the phenotypically normal leaf samples, leading to a preliminary conclusion that histone deacetylation suppressed gene expression and contributed to the development of somaclonal variants.
The natural progression and outcomes of adrenal incidentaloma: a systematic review and meta-analysis

Loh HH, Yee A, Loh HS, Sukor N, Kamaruddin NA

Minerva Endocrinol., 2015 Dec 23.
PMID: 26698544 DOI: 10.23736/S0391-1977.16.02394-4

INTRODUCTION: Long-term outcome of patients with adrenal incidentaloma (AI) is unknown. The aim of this study was to systematically summarize the follow-up and outcome of clinically silent AI who do not undergo surgery.
EVIDENCE ACQUISITION: All major databases and medical literature in English-language, published from 1998 to May 2015, were systematically searched for publications on AI. Primary endpoint was hormonal hyper function; secondary endpoints were time from diagnosis to study endpoint and the outcome of adrenalectomy. Meta-analysis was performed using both qualitative and quantitative approach.
EVIDENCE SYNTHESIS: A total of 11 publications were included. Total sample size was 1298 patients. Mean follow-up duration was 44.2 months. There were 82 patients confirmed to have subclinical Cushing's syndrome at diagnosis, with 1.79% new cases at the end of follow up (95% CI, 0.002 to 0.045). Incidence of Cushing's syndrome was 0.7% (95% CI, 0.001 to 0.013) and pheochromocytoma 0.4% (95% CI, 0.001 to 0.008). The mean tumor size was 2.52cm, with mean increment of 0.03cm to 2.9cm at the end of follow up. About 3% of patients ended up with surgery (95% CI, 0.01 to 0.05) but none were due to primary adrenal malignancy. Time of greatest risk of developing Cushing's syndrome and pheochromocytoma was between months 36 and 42 (hazard rate 14%), and between months 48 and 54 (hazard rate 7%) respectively.
CONCLUSIONS: Malignant change in non-functioning AI is rare. The risk of developing overt disease over the follow-up period is low. A less stringent imaging and functional work-up interval can be considered.
Fulltext Inhibitory effect of Duabanga grandiflora on MRSA biofilm formation via prevention of cell-surface attachment and PBP2a production

Santiago C, Lim KH, Loh HS, Ting KN

Molecules, 2015 Mar 10;20(3):4473-82.
PMID: 25764489 DOI: 10.3390/molecules20034473

Formation of biofilms is a major factor for nosocomial infections associated with methicillin-resistance Staphylococcus aureus (MRSA). This study was carried out to determine the ability of a fraction, F-10, derived from the plant Duabanga grandiflora to inhibit MRSA biofilm formation. Inhibition of biofilm production and microtiter attachment assays were employed to study the anti-biofilm activity of F-10, while latex agglutination test was performed to study the influence of F-10 on penicillin-binding protein 2a (PBP2a) level in MRSA biofilm. PBP2a is a protein that confers resistance to beta-lactam antibiotics. The results showed that, F-10 at minimum inhibitory concentration (MIC, 0.75 mg/mL) inhibited biofilm production by 66.10%; inhibited cell-surface attachment by more than 95%; and a reduced PBP2a level in the MRSA biofilm was observed. Although ampicilin was more effective in inhibiting biofilm production (MIC of 0.05 mg/mL, 84.49%) compared to F-10, the antibiotic was less effective in preventing cell-surface attachment. A higher level of PBP2a was detected in ampicillin-treated MRSA showing the development of further resistance in these colonies. This study has shown that F-10 possesses anti-biofilm activity, which can be attributed to its ability to reduce cell-surface attachment and attenuate the level of PBP2a that we postulated to play a crucial role in mediating biofilm formation.
Anhedonia among patients with Major Depressive Disorder: A comparison between patients on escitalopram and healthy controls

Ng CG, Wong SK, Loh HS, Yee A

Clin Ter, 2014;165(6):e384-90.
PMID: 25524191 DOI: 10.7417/CT.2014.1778

BACKGROUND AND AIMS: Escitalopram has widely been recognized as one of the most frequently used antidepressants, with superior tolerability and great efficacy in preventing major depressive disorder (MDD) relapse and recurrence. However, anhedonia, which is a core symptom of MDD, remains difficult to treat. This study investigates the hedonic levels of MDD patients treated with Escitalopram.

MATERIALS AND METHODS: A total of 108 participants, 26 of whom with MDD on Escitalopram, were recruited in this cross sectional study. They were evaluated using the Snaith-Hamilton Pleasure Scale (SHAPS) and Beck Depression Inventory (BDI) questionnaires to assess their hedonic state, general mental health condition and level of depression.

RESULTS: Our study shows that most items in the SHAPS scores are significantly different between MDD patients on Escitalopram and the controls.

CONCLUSIONS: The hedonic capacity remains different between the two groups despite patients with MDD are put on Escitalopram treatment. Escitalopram fails to alleviate the hedonic state of MDD patients. Antidepressants that improve both depressive symptoms and hedonic states should be considered when treating MDD patients in clinical settings.
The prevalence of sexual dysfunction among male patients on methadone and buprenorphine treatments: a meta-analysis study

Yee A, Loh HS, Hisham Hashim HM, Ng CG

J Sex Med, 2014 Jan;11(1):22-32.
PMID: 24344738 DOI: 10.1111/jsm.12352

INTRODUCTION: For many years, methadone has been recognized as an effective maintenance treatment for opioid dependence. However, of the many adverse events reported, sexual dysfunction is one of the most common side effects.
AIM: We conducted a meta-analysis to evaluate the prevalence of sexual dysfunction among male patients on methadone and buprenorphine treatments.
METHODS: Relevant studies published from inception until December 2012 were identified by searching PubMed, OVID, and Embase. Studies were selected using prior defined criteria. Heterogeneity, publication bias, and odds ratio were assessed thoroughly.
MAIN OUTCOME MEASURES: To examine the prevalence and odds ratio of sexual dysfunctions among the methadone and buprenorphine groups.
RESULTS: A total of 1,570 participants from 16 eligible studies were identified in this meta-analysis. The studies provided prevalence estimates for sexual dysfunction among methadone users with a meta-analytical pooled prevalence of 52% (95% confidence interval [CI], 0.39-0.65). Only four studies compared sexual dysfunction between the two groups, with a significantly higher combined odds ratio in the methadone group (OR = 4.01, 95% CI, 1.52-10.55, P = 0.0049).
CONCLUSIONS: Evidence showed that the prevalence of sexual dysfunction was higher among the users of methadone compared with buprenorphine. Patients with sexual difficulty while on methadone treatment were advised to switch to buprenorphine.
Fulltext New estimates of CMV seroprevalence in Malaysia. Where do we go from here?

Camalxaman SN, Zeenathul NA, Quah YW, Zuridah H, Loh HS

Med J Malaysia, 2012 Apr;67(2):231.
PMID: 22822655
Comparative studies of dipeptidyl peptidase 4 inhibitor vs sulphonylurea among Muslim Type 2 diabetes patients who fast in the month of Ramadan: A systematic review and meta-analysis

Loh HH, Yee A, Loh HS, Sukor N, Kamaruddin NA

Prim Care Diabetes, 2016 Jun;10(3):210-9.
PMID: 26392074 DOI: 10.1016/j.pcd.2015.09.001

AIM: To systematically review the literature to compare the use of DPP4 inhibitors vs sulphonylurea in type 2 diabetic Muslim patients who fast in Ramadan, with regards to its safety, tolerability, glycemic control, and body weight changes.
METHODS: All English-language medical literature published from inception till October 2014 which met the inclusion criteria were reviewed and analyzed.
RESULTS: A total of nine papers were included, reviewed and analyzed. The total sample size was 4276 patients. All studies used either of the two DPP4 inhibitors - Vildagliptin or Sitagliptin, vs sulphonylurea or meglitinides. Patients receiving DPP4 inhibitors were less likely to develop symptomatic hypoglycemia (risk ratio 0.46; 95% CI, 0.30-0.70), confirmed hypoglycemia (risk ratio 0.36; 95% CI, 0.21-0.64) and severe hypoglycemia (risk ratio 0.22; 95% CI, 0.10-0.53) compared with patients on sulphonylureas. There was no statistically significant difference in HbA1C changes comparing Vildagliptin and sulphonylurea.
CONCLUSION: DPP4 inhibitor is a safer alternative to sulphonylurea in Muslim patients with type 2 diabetes mellitus who fast during the month of Ramadan as it is associated with lower risk of symptomatic, confirmed and severe hypoglycemia, with efficacy comparable to sulphonylurea.
Synergistic cytotoxic effects of combined δ-tocotrienol and jerantinine B on human brain and colon cancers

Abubakar IB, Lim KH, Kam TS, Loh HS

J Ethnopharmacol, 2016 May 26;184:107-18.
PMID: 26947901 DOI: 10.1016/j.jep.2016.03.004

The genus Tabernaemontana has widespread distribution throughout tropical and subtropical parts of the world, i.e. Africa, Asia and America which has long been used for treatments of different disease conditions including tumours, wounds, syphilis, stomach ache and headache. Some Tabernaemontana species are used for treatment of piles, spleen and abdominal tumours in India. In particular, the leaf of Tabernaemontana corymbosa is used for treatment of tumours in Bangladesh. Parts of the plant or whole plants are used as decoctions, steam bath, powder and ointments.
Fulltext Conjugation of insulin onto the sidewalls of single-walled carbon nanotubes through functionalization and diimide-activated amidation

Ng CM, Loh HS, Muthoosamy K, Sridewi N, Manickam S

Int J Nanomedicine, 2016;11:1607-14.
PMID: 27143882 DOI: 10.2147/IJN.S98726

The high aspect ratio of carbon nanotubes (CNTs) allows the attachment of compounds that enhance the functionality of the drug vehicle. Considering this, use of CNTs as a multifunctional insulin carrier may be an interesting prospect to explore.
Fulltext Prevention of cell-surface attachment and reduction of penicillin-binding protein 2a (PBP2a) level in methicillin-resistant Staphylococcus aureus biofilms by Acalypha wilkesiana

Santiago C, Lim KH, Loh HS, Ting KN

BMC Complement Altern Med, 2015;15:79.
PMID: 25880167 DOI: 10.1186/s12906-015-0615-6

Formation of biofilm is known to enhance the virulence of methicillin-resistance Staphylococcus aureus (MRSA), which is associated with persistent infections in hospital settings. The biofilm layer essentially forms a protective barrier encapsulating the bacterial colony and thus reduces the effectiveness of chemotherapeutics. We have isolated 9EA-FC-B bioactive fraction from Acalypha wilkesiana Müll. Arg. that reverses ampicillin resistant in MRSA through inhibition of the antibiotic resistant protein, penicillin-binding protein 2a (PBP2a). In this study, we aimed to investigate the effects of 9EA-FC-B on MRSA biofilm forming capacity.

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