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Intra-specific hybridization: generator of genetic diversification and heterosis in Andrographis paniculata Nees. A bridge from extinction to survival

Valdiani A, Kadir MA, Saad MS, Talei D, Tan SG

Gene, 2012 Aug 15;505(1):23-36.
PMID: 22683537 DOI: 10.1016/j.gene.2012.05.056

Andrographis paniculata (AP) has been stated as a low-diverse, endangered and red-listed plant species. Self-pollinated mating system, being an introduced species and experiencing a bottleneck as well as over exploitation cause such a consequence. Inter and intra-specific hybridizations have been suggested as essential techniques for generating genetic diversity. To test the effect of intra-specific hybridization on diversification and heterosis of AP, seven accessions were outcrossed manually in all 21 possible combinations. Three types of markers including morphological, phytochemical and RAPD markers were employed to evaluate the mentioned hypothesis. The results revealed that hybridization acted as a powerful engine for diversification of AP as it caused heterotic expression of the studied traits, simultaneously. Initially, it seems that additive and non-additive gene effects both can be considered as the genetic basis of heterosis in AP for the investigated traits. Agronomic and morphological traits were differentiated from each other, while positive heterosis was recorded mainly for agronomic traits but not for the morphological traits. Intra-specific hybridization increased the genetic diversity in AP population. Nevertheless, a part of this variation could also be attributed to the negative heterosis. The current exploration demonstrated the first ever conducted manual intra-specific hybridization among AP accessions in a mass scale. However, the 17 RAPD primers produced a monomorph pattern, but perhaps increasing the number of markers can feature a new genetic profile in this plant.
Fulltext Attenuation of influenza virus infectivity with herbal-marine compound (HESA-A): an in vitro study in MDCK cells

Mehrbod P, Ideris A, Omar AR, Hair-Bejo M, Tan SW, Kheiri MT, et al.

Virol J, 2012;9:44.
PMID: 22340010 DOI: 10.1186/1743-422X-9-44

The influenza virus is still one of the most important respiratory risks affecting humans which require effective treatments. In this case, traditional medications are of interest. HESA-A is an active natural biological compound from herbal-marine origin. Previous studies have reported that the therapeutic properties of HESA-A are able to treat psoriasis vulgaris and cancers. However, no antiviral properties have been reported.
Membrane technology as a promising alternative in biodiesel production: a review

Shuit SH, Ong YT, Lee KT, Subhash B, Tan SH

Biotechnol Adv, 2012 Nov-Dec;30(6):1364-80.
PMID: 22366515 DOI: 10.1016/j.biotechadv.2012.02.009

In recent years, environmental problems caused by the use of fossil fuels and the depletion of petroleum reserves have driven the world to adopt biodiesel as an alternative energy source to replace conventional petroleum-derived fuels because of biodiesel's clean and renewable nature. Biodiesel is conventionally produced in homogeneous, heterogeneous, and enzymatic catalysed processes, as well as by supercritical technology. All of these processes have their own limitations, such as wastewater generation and high energy consumption. In this context, the membrane reactor appears to be the perfect candidate to produce biodiesel because of its ability to overcome the limitations encountered by conventional production methods. Thus, the aim of this paper is to review the production of biodiesel with a membrane reactor by examining the fundamental concepts of the membrane reactor, its operating principles and the combination of membrane and catalyst in the catalytic membrane. In addition, the potential of functionalised carbon nanotubes to serve as catalysts while being incorporated into the membrane for transesterification is discussed. Furthermore, this paper will also discuss the effects of process parameters for transesterification in a membrane reactor and the advantages offered by membrane reactors for biodiesel production. This discussion is followed by some limitations faced in membrane technology. Nevertheless, based on the findings presented in this review, it is clear that the membrane reactor has the potential to be a breakthrough technology for the biodiesel industry.
Assays for aptamer-based platforms

Citartan M, Gopinath SC, Tominaga J, Tan SC, Tang TH

Biosens Bioelectron, 2012 Apr 15;34(1):1-11.
PMID: 22326894 DOI: 10.1016/j.bios.2012.01.002

Aptamers are single stranded DNA or RNA oligonucleotides that have high affinity and specificity towards a wide range of target molecules. Aptamers have low molecular weight, amenable to chemical modifications and exhibit stability undeterred by repetitive denaturation and renaturation. Owing to these indispensable advantages, aptamers have been implemented as molecular recognition element as alternative to antibodies in various assays for diagnostics. By amalgamating with a number of methods that can provide information on the aptamer-target complex formation, aptamers have become the elemental tool for numerous biosensor developments. In this review, administration of aptamers in applications involving assays of fluorescence, electrochemistry, nano-label and nano-constructs are discussed. Although detection strategies are different for various aptamer-based assays, the core of the design strategies is similar towards reporting the presence of specific target binding to the corresponding aptamers. It is prognosticated that aptamers will find even broader applications with the development of new methods of transducing aptamer target binding.
Clinicopathological features and survival of testicular tumours in a Southeast Asian university hospital: a ten-year review

Tan GH, Azrif M, Shamsul AS, Ho CC, Praveen S, Goh EH, et al.

Asian Pac J Cancer Prev, 2011;12(10):2727-30.
PMID: 22320982

INTRODUCTION: Testicular cancer mainly affects young men worldwide. There is lack of published data on patients with this malignant condition from the Southeast Asian region. The aim of this study was therefore to determine the clinicopathologic features of testicular cancer patients treated in a Southeast Asian university hospital and their overall survival rate.
MATERIALS AND METHODS: This was a retrospective study of testicular cancer patients treated between January 2001 and February 2011. Their epidemiological data, clinical presentation, pathologic diagnosis, stage of disease and treatment were gathered and the overall survival rate of this cohort was analyzed.
RESULTS: Thirty-one patients were included in this study. The majority of them were of Malay ethnicity. The average age at presentation was 33.7 years. The commonest testicular cancer was non-seminomatous germ cell tumour, followed by seminoma, lymphoma and rhabdomyosarcoma. More than half of all testicular germ cell tumour (GCT) patients had some form of metastasis at diagnosis. All the patients were treated with radical orchidectomy. Adjuvant chemotherapy was given to those with metastatic disease. Four seminoma patients received radiotherapy to the para-aortic lymph nodes. The 5-year survival rate for all testicular cancers in this cohort was 83.9%. The survival rate was 88.9% in 5 years when GCT were analyzed separately.
CONCLUSION: GCT affects patients in their third and fourth decades of life while lymphoma patients are generally older. Most of the patients treated for GCT are of Malay ethnicity. The majority have late presentation for treatment. The survival rate of GCT patients treated here is comparable to other published series in other parts of the world.
Fulltext Draft genome sequence of Mycobacterium bolletii strain M24, a rapidly growing mycobacterium of contentious taxonomic status

Wong YL, Choo SW, Tan JL, Ong CS, Ng KP, Ngeow YF

J Bacteriol, 2012 Aug;194(16):4475.
PMID: 22843600 DOI: 10.1128/JB.00916-12

The whole-genome sequence of Mycobacterium bolletii M24, isolated from the bronchoalveolar lavage fluid of a Malaysian patient, is reported here. The circular chromosome of 5,507,730 bp helped to clarify the taxonomic position of this organism within the M. abscessus complex and revealed the presence of proteins potentially important for pathogenicity in a human host.
Fulltext Outcome of coronary artery bypass grafting in end stage renal disease patients

Koh KH, Tan C, Hii L, Ong TK, Jong YH

Med J Malaysia, 2012 Apr;67(2):173-6.
PMID: 22822638 MyJurnal

End stage renal disease (ESRD) patients have a much higher rate of cardiac disease and cardiac mortality as compared with the general population. Revascularisation such as coronary artery bypass grafting (CABG) may also carry a higher rate of complications and morbidity. We compared our ESRD patients who underwent CABG with the general population and ESRD population.
Fulltext Iatrogenic ureter injuries: eleven years experience in a tertiary hospital

Mahendran HA, Singam P, Ho C, Goh EH, Tan GH, Zuklifli MZ

Med J Malaysia, 2012 Apr;67(2):169-72.
PMID: 22822637 MyJurnal

Iatrogenic ureteric injuries are rare complications of abdomino-pelvic surgery but associated with high morbidity from infection and possible loss of renal function. A successful repair is related to the timing of diagnosis, site of injury and method of repair. This study was a retrospective review of outcomes of iatrogenic ureteric injury and factors contributing to successful operative repair. Twenty consecutive cases referred to the Urology Unit of the UKM Medical Center during an 11-year period from 1998 to 2009 were reviewed. Thirteen patients were diagnosed intraoperatively and underwent immediate repair. Seven patients had delayed diagnosis but also underwent immediate repair. In our series, there was no significant difference in outcome between injuries diagnosed intraoperatively versus injuries with delayed diagnosis. There was significant difference in the outcomes between methods of ureteric repair where ureter reimplantation via psoas hitch or Boari flap yielded better results than primary end-to-end anastomosis Three patients suffered loss of renal function from unsuccessful ureter repair. We conclude that all iatrogenic ureteric injury should be repaired immediately in the absence of overt sepsis. Ureter reimplantation using a Boari flap or psoas hitch is preferred to the end-to-end anastomosis especially when there is delayed diagnosis
Fulltext Severe diabetic papillopathy mimicking non-arteritic anterior ischemic optic neuropathy (NAION) in a young patient

Mallika PS, Salowi MA, Thanaraj A, Chong MS, Tan AK, Chua CN

Med J Malaysia, 2012 Apr;67(2):228-30.
PMID: 22822654 MyJurnal

With the pathophysiology not clearly understood and fewer than 130 cases having been reported in the literature, diabetic papillopathy presents a special challenge to the ophthalmologist. We report a case of a young patient with more than 12 years of type 1 diabetes mellitus (T1DM) on insulin with poor compliance to treatment who presented with sudden bilateral loss of vision. Ocular examination, fluorescence angiography (FA) and systemic signs were conclusive of diabetic papillopathy. His fasting blood sugar level was high and serum glycosylated haemoglobin (HbA1c) indicated a long term fluctuating blood glucose control. His vision initially improved with treatment, but later deteriorated with tight glycemic control.
Fulltext Genetic dissection of sympatric populations of brown planthopper, Nilaparvata lugens (Stål), using DALP-PCR molecular markers

Latif MA, Rafii MY, Mazid MS, Ali ME, Ahmed F, Omar MY, et al.

ScientificWorldJournal, 2012;2012:586831.
PMID: 22593700 DOI: 10.1100/2012/586831

Direct amplified length polymorphism (DALP) combines the advantages of a high-resolution fingerprint method and also characterizing the genetic polymorphisms. This molecular method was also found to be useful in brown planthopper, Nilaparvata lugens species complex for the analysis of genetic polymorphisms. A total of 11 populations of Nilaparvata spp. were collected from 6 locations from Malaysia. Two sympatric populations of brown planthopper, N. lugens, one from rice and the other from a weed grass (Leersia hexandra), were collected from each of five locations. N. bakeri was used as an out group. Three oligonucleotide primer pairs, DALP231/DALPR'5, DALP234/DALPR'5, and DALP235/DALPR'5 were applied in this study. The unweighted pair group method with arithmetic mean (UPGMA) dendrogram based on genetic distances for the 11 populations of Nilaparvata spp. revealed that populations belonging to the same species and the same host type clustered together irrespective of their geographical localities of capture. The populations of N. lugens formed into two distinct clusters, one was insects with high esterase activities usually captured from rice and the other was with low esterase activities usually captured from L. hexandra. N. bakeri, an out group, was the most isolated group. Analyses of principal components, molecular variance, and robustness also supported greatly to the findings of cluster analysis.
Fulltext Dengue infection and miscarriage: a prospective case control study

Tan PC, Soe MZ, Si Lay K, Wang SM, Sekaran SD, Omar SZ

PLoS Negl Trop Dis, 2012;6(5):e1637.
PMID: 22590658 DOI: 10.1371/journal.pntd.0001637

Dengue is the most prevalent mosquito borne infection worldwide. Vertical transmissions after maternal dengue infection to the fetus and pregnancy losses in relation to dengue illness have been reported. The relationship of dengue to miscarriage is not known.
Perhentidines A-C: macroline-macroline bisindoles from Alstonia and the absolute configuration of perhentinine and macralstonine

Lim SH, Low YY, Tan SJ, Lim KH, Thomas NF, Kam TS

J Nat Prod, 2012 May 25;75(5):942-50.
PMID: 22559995 DOI: 10.1021/np300120p

Three new bisindole alkaloids of the macroline-macroline type, perhentidines A-C (1-3), were isolated from the stem-bark extract of Alstonia macrophylla and Alstonia angustifolia. The structures of these alkaloids were established on the basis of NMR and MS analyses. The absolute configurations of perhentinine (4) and macralstonine (5) were established by X-ray diffraction analyses, which facilitated assignment of the configuration at C-20 in the regioisomeric bisindole alkaloids perhentidines A-C (1-3). A potentially useful method for the determination of the configuration at C-20 based on comparison of the NMR chemical shifts of the bisindoles and their acetate derivatives, in these and related bisindoles with similar constitution and branching of the monomeric units, is also presented.
Development of a thermostabilized, one-step, nested, tetraplex PCR assay for simultaneous identification and differentiation of Entamoeba species, Entamoeba histolytica and Entamoeba dispar from stool samples

Foo PC, Chan YY, See Too WC, Tan ZN, Wong WK, Lalitha P, et al.

J Med Microbiol, 2012 Sep;61(Pt 9):1219-1225.
PMID: 22556327 DOI: 10.1099/jmm.0.044552-0

Entamoeba histolytica is the only Entamoeba species that causes amoebiasis in humans. Approximately 50 million people are infected, with 100, 000 deaths annually in endemic countries. Molecular diagnosis of Entamoeba histolytica is important to differentiate it from the morphologically identical Entamoeba dispar to avoid unnecessary medication. Conventional molecular diagnostic tests require trained personnel, cold-chain transportation and/or are storage-dependent, which make them user-unfriendly. The aim of this study was to develop a thermostabilized, one-step, nested, tetraplex PCR assay for the detection of Entamoeba histolytica, Entamoeba dispar and Entamoeba species in cold-chain-free and ready-to-use form. The PCR test was designed based on the Entamoeba small subunit rRNA (SSU-rRNA) gene, which detects the presence of any Entamoeba species, and simultaneously can be used to differentiate Entamoeba histolytica from Entamoeba dispar. In addition, a pair of primers was designed to serve as an internal amplification control to help identify inhibitors in the samples. All PCR reagents together with the designed primers were thermostabilized by lyophilization and were stable at 24 °C for at least 6 months. The limit of detection of the tetraplex PCR was found to be 39 pg DNA or 1000 cells for Entamoeba histolytica and 78 pg DNA or 1000 cells for Entamoeba dispar, and the specificity was 100 %. In conclusion, this cold-chain-free, thermostabilized, one-step, nested, multiplex PCR assay was found to be efficacious in differentiating Entamoeba histolytica from other non-pathogenic Entamoeba species.
Single-stranded DNA (ssDNA) production in DNA aptamer generation

Marimuthu C, Tang TH, Tominaga J, Tan SC, Gopinath SC

Analyst, 2012 Mar 21;137(6):1307-15.
PMID: 22314701 DOI: 10.1039/c2an15905h

The discovery that synthetic short chain nucleic acids are capable of selective binding to biological targets has made them to be widely used as molecular recognition elements. These nucleic acids, called aptamers, are comprised of two types, DNA and RNA aptamers, where the DNA aptamer is preferred over the latter due to its stability, making it widely used in a number of applications. However, the success of the DNA selection process through Systematic Evolution of Ligands by Exponential Enrichment (SELEX) experiments is very much dependent on its most critical step, which is the conversion of the dsDNA to ssDNA. There is a plethora of methods available in generating ssDNA from the corresponding dsDNA. These include asymmetric PCR, biotin-streptavidin separation, lambda exonuclease digestion and size separation on denaturing-urea PAGE. Herein, different methods of ssDNA generation following the PCR amplification step in SELEX are reviewed.
Fulltext Basic fibroblast growth factor modulates cell cycle of human umbilical cord-derived mesenchymal stem cells

Ramasamy R, Tong CK, Yip WK, Vellasamy S, Tan BC, Seow HF

Cell Prolif, 2012 Apr;45(2):132-9.
PMID: 22309282 DOI: 10.1111/j.1365-2184.2012.00808.x

BACKGROUND: Mesenchymal stem cells (MSC) have great potential in regenerative medicine, immunotherapy and gene therapy due to their unique properties of self-renewal, high plasticity, immune modulation and ease for genetic modification. However, production of MSC at sufficient clinical scale remains an issue as in vitro generation of MSC inadequately fulfils the demand with respect to patients.
OBJECTIVES: This study has aimed to establish optimum conditions to generate and characterize MSC from human umbilical cord (UC-MSC).
MATERIALS AND METHODS: To optimize MSC population growth, basic fibroblast growth factor (bFGF) was utilized in culture media. Effects of bFGF on expansion kinetics, cell cycle, survival of UC-MSC, cytokine secretion, expression of early stem-cell markers and immunomodulation were investigated.
RESULTS: bFGF supplementation profoundly enhanced UC-MSC proliferation by reducing population doubling time without altering immunophenotype and immunomodulatory function of UC-MSC. However, cell cycle studies revealed that bFGF drove the cells into the cell cycle, as a higher proportion of cells resided in S phase and progressed into M phase. Consistent with this, bFGF was shown to promote expression of cyclin D proteins and their relevant kinases to drive UC-MSC to transverse cell cycle check points, thus, committing the cells to DNA synthesis. Furthermore, supplementation with bFGF changed the cytokine profiles of the cells and reduced their apoptotic level.
CONCLUSION: Our study showed that bFGF supplementation of UC-MSC culture enhanced the cells' growth kinetics without compromising their nature.
Fulltext An unusual entry site of an intraorbital foreign body in a child

Mallika PS, Chong YJ, Tan AK, Tang IP, Aziz S, Lee HK

Med J Malaysia, 2011 Oct;66(4):361-2.
PMID: 22299559 MyJurnal

Intraorbital foreign bodies (IOrbFB) are associated with both sight and life threatening injuries. We report a case of an IOrbFB associated with retrobulbar hemorrhage and injury of the frontal sinus in an 11 year-old boy, after history of fall from the tree. Imaging studies revealed a metallic foreign body (FB) in the orbit and fracture of the walls of the frontal sinus. The usual entry route of an IOrbFB is either through the eye or orbital walls and extremely rare through the paranasal sinuses. This is the first reported case of a FB entering the orbit through the frontal sinus.
Fulltext Food assimilated by two sympatric populations of the brown planthopper Nilaparvata lugens (Delphacidae) feeding on different host plants contaminates insect DNA detected by RAPD-PCR analysis

Latif MA, Omar MY, Tan SG, Siraj SS, Ali ME, Rafii MY

Genet. Mol. Res., 2012;11(1):30-41.
PMID: 22290463 DOI: 10.4238/2012.January.9.4

Contamination of insect DNA for RAPD-PCR analysis can be a problem because many primers are non-specific and DNA from parasites or gut contents may be simultaneously extracted along with that of the insect. We measured the quantity of food ingested and assimilated by two sympatric populations of brown planthopper (BPH), Nilaparvata lugens, one from rice and the other from Leersia hexandra (Poaceae), a wetland forage grass, and we also investigated whether host plant DNA contaminates that of herbivore insects in extractions of whole insects. Ingestion and assimilation of food were reduced significantly when individuals derived from one host plant were caged on the other species. The bands, OPA3 (1.25), OPD3 (1.10), OPD3 (0.80), OPD3 (0.60), pUC/M13F (0.35), pUC/M13F (0.20), BOXAIR (0.50), peh#3 (0.50), and peh#3 (0.17) were found in both rice-infesting populations of brown planthopper and its host plant (rice). Similarly, the bands, OPA4 (1.00), OPB10 (0.70), OPD3 (0.90), OPD3 (0.80), OPD3 (0.60), pUC/ M13F (0.35), pUC/M13F (0.20), and BOXAIR (0.50) were found in both Leersia-infesting populations of brown planthopper and the host plant. So, it is clear that the DNA bands amplified in the host plants were also found in the extracts from the insects feeding on them.
Fulltext mRNA expression of EgCHI1, EgCHI2, and EgCHI3 in oil palm leaves (Elaeis guineesis Jacq.) after treatment with Ganoderma boninense pat. and Trichoderma harzianum Rifai

Naher L, Tan SG, Ho CL, Yusuf UK, Ahmad SH, Abdullah F

ScientificWorldJournal, 2012;2012:647504.
PMID: 22919345 DOI: 10.1100/2012/647504

Basal stem rot (BSR) disease caused by the fungus Ganoderma boninense is the most serious disease affecting the oil palm; this is because the disease escapes the early disease detection. The biocontrol agent Trichoderma harzianum can protect the disease only at the early stage of the disease. In the present study, the expression levels of three oil palm (Elaeis guineensis Jacq.) chitinases encoding EgCHI1, EgCHI2, and EgCHI3 at 2, 5, and 8 weeks inoculation were measured in oil palm leaves from plants treated with G. boninense or T. harzianum alone or both.
Epidemiology of spinal cord injury in Hospital Kuala Lumpur

Ibrahim A, Lee KY, Kanoo LL, Tan CH, Hamid MA, Hamedon NM, et al.

Spine (Phila Pa 1976), 2013 Mar 1;38(5):419-24.
PMID: 22914700 DOI: 10.1097/BRS.0b013e31826ef594

Cross-sectional study.
Fulltext Genetic relatedness of low solitary nests of Apis dorsata from Marang, Terengganu, Malaysia

Sahebzadeh N, Mardan M, Ali AM, Tan SG, Adam NA, Lau WH

PLoS One, 2012;7(7):e41020.
PMID: 22911733 DOI: 10.1371/journal.pone.0041020

Knowledge on the population of genetic structure and ecological behaviour of Apis dorsata from Peninsular Malaysia is needed for effective management and conservation of this species since unsustainable whole solitary low nest cutting for product harvesting is the current common practice here. The analysis of 15 single locus DNA microsatellite markers on samples from 20 solitary nests of A. dorsata showed that while these markers were polymorphic, high intracolonial relatedness existed. Furthermore, in general, slightly negative values of intercolony relatedness (R) among the nests of A. dorsata were found. However, positive values of mean intercolony relatedness were observed between 54 pairs of nests out of 190 possible combinations. The R values among nest pairs 3-4 and 3-5 was higher than 0.50 showing that their queens were half siblings, whereas nest pair 19-20 showed relatedness of 0.95 indicating that the same queen was sampled. The results that we obtained could not conclusively support the hypothesis of this study that the honey hunters in Marang district of Malaysia repeatedly harvest the same nest located at a different site and at a different time during the same honey harvesting season. However, our finding of an appreciable level of intercolonial relatedness between several pairs of nests in this pioneer study indicated that a comprehensive study with a larger sample size of solitary nests found throughout the region would be necessary to provide concrete proof for this novel idea.

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