Displaying publications 81 - 100 of 330 in total

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  1. Mok PL, Cheong SK, Leong CF
    Malays J Pathol, 2008 Jun;30(1):11-9.
    PMID: 19108406 MyJurnal
    Mesenchymal stem cells are pluripotent progenitors that could be found in human bone marrow. Mesenchymal stem cells are capable of renewing themselves without differentiation in long-term culture. These cells also have low immunogenicity and can suppress alloreactive T cell responses. In the current study, mesenchymal stem cells isolated and propagated previously from the bone marrow of a megaloblastic anaemia patient were tested for their capabilities to differentiate into adipocytes, chondrocytes and osteoblasts in vitro. The differentiated cells were determined by Oil Red O, Alcian Blue-PAS and Alizarin Red S staining, and reverse transcriptase-polymerase chain reaction to determine the expression of mRNA specific for adipogenesis, chondrogenesis and osteogenesis. The results showed that the fibroblast-like cells were capable of differentiating into adipocytes, chondrocytes and osteoblasts upon chemical induction. The adipocytes, chondrocytes and osteoblasts were stained positively to Oil Red O, Alcian Blue-PAS and Alizarin Red S respectively. The differentiated cells were also found to express mRNA specific for adipogenesis ('peroxisome proliferation-activated receptor gamma2' and lipoprotein lipase), chondrogenesis (collagen type II) and osteogenesis (osteocalcin, osteopontin and alkaline phosphatase). In conclusion, this research has successfully isolated fibroblast-like cells from human bone marrow and these cells demonstrated morphological, cytochemical and immunochemical characteristics similar to mesenchymal stem cells. These cells maintain their proliferative properties and could be differentiated into the mesoderm lineage. The success of this study is vital because mesenchymal stem cells can be used in cellular therapy to regenerate or replace damaged tissues, or as a vehicle for therapeutic gene delivery in the future.
    Matched MeSH terms: Reverse Transcriptase Polymerase Chain Reaction
  2. Kumari N, Navaratnam P, Sekaran SD
    J Infect Dev Ctries, 2008 Jun 01;2(3):193-9.
    PMID: 19738350
    BACKGROUND: Streptococcus pneumoniae is a major human pathogen. The emergence of penicillin resistant strains since the 1970s has been life threatening and the evolution of the bacteria have enabled itself to develop resistance to many other antibiotics such as the macrolides and the fluoroquinolones. This study aims to characterize S. pneumoniae isolates for the presence of penicillin and macrolide resistance genes.

    METHODOLOGY: One hundred and twenty clinical isolates of S. pneumoniae were obtained from patients of University Malaya Medical Centre (UMMC). The strains were screened using a multiplex real-time PCR method for the presence of alterations in the genes encoding the penicillin binding proteins: pbp2b, macrolide resistance determinant ermB and the pneumolysin gene, ply. Dual-labelled Taqman probes were used in the real-time detection method comprising three different genes labeled with individual fluorophores at different wavelengths. One hundred and twenty isolates from bacterial cultures and isolates directly from blood cultures samples were analyzed using this assay.

    RESULTS: A multiplex PCR comprising the antibiotic resistance genes, ermB and and pneumolysin gene (ply), a S. pneumoniae species specific gene, was developed to characterize strains of S. pneumoniae. Out of the 120 pneumococcal isolates, 58 strains were categorized as Penicillin Sensitive Streptococcus pneumoniae (PSSP), 36 as Penicillin Intermediate Streptococcus pneumoniae (PISP) and 26 as Penicillin Resistant Streptococcus pneumoniae (PRSP). All the 58 PSSP strains harboured the pbp2b gene while the 36 PISP and 26 PRSP strains did not harbour this gene, thus suggesting reduced susceptibility to penicillin. Resistance to erythromycin was observed in 47 of the pneumococcal strains while 15 and 58 were intermediate and sensitive to this drug respectively. Susceptibility testing to other beta-lactams (CTX and CRO) also showed reduced susceptibility among the strains within the PISP and PRSP groups but most PSSP strains were sensitive to other antibiotics.

    CONCLUSION: The characterization of pneumococcal isolates for penicillin and erythromycin resistance genes could be useful to predict the susceptibility of these isolates to other antibiotics, especially beta-lactams drugs. We have developed an assay with a shorter turnaround time to determine the species and resistance profile of Streptococcus pneumoniae with respect to penicillin and macrolides using the Real Time PCR format with fluorescent labeled Taqman probes, hence facilitating earlier and more definitive antimicrobial therapy which may lead to better patient management.

    Matched MeSH terms: Reverse Transcriptase Polymerase Chain Reaction
  3. Hamid AA, Ruszymah BH, Aminuddin BS, Sathappan S, Chua KH
    Med J Malaysia, 2008 Jul;63 Suppl A:9-10.
    PMID: 19024959
    Human adipose-derived stem cells (HADSC) have demonstrated the capacity of differentiating into bone depending on the specific induction stimuli and growth factors. However, investigation on stem cell characteristic after osteogenic differentiation is still lacking. The goal of this study was to investigate the differential expression of sternness and osteogenic genes in non-induced HADSC compared with HADSC after osteogenic induction using quantitative Real Time RT-PCR. Our results showed that OCT-4, REX-1, FZD9, OSC, RUNX, and ALP were up regulated after osteogenic induction. This may indicated that HADSCs after osteogenic induction still possessed some stemness properties.
    Matched MeSH terms: Reverse Transcriptase Polymerase Chain Reaction
  4. Tan GC, Simat SF, Abdul Rahman H, Tan AE, Chua KH
    Med J Malaysia, 2008 Jul;63 Suppl A:51-2.
    PMID: 19024979
    The aim of the study is to determine the neuronal and glial gene expression of cultured human amniotic epithelial cells (HAECs) in serial passages. HAECs obtained from human term placentae were cultured in F12:DMEM (1:1) + 10% FBS +10ng/ml EGF in serial passages. Quantitative RT-PCR was used to assess the gene expression analysis. The results showed that the cultured HAECs expressed the neural stem cell genes (Nestin, NSE and Vimentin), mature neuronal genes (TH, MAP-2, beta-III-tubulin and NFM) and glial genes (CNPase, MBP and Olig). These neural stem cell genes increased with serial passages while the genes expression for mature neuronal and glial cells were downregulated. These results suggested that HAECs may promote or involve in neurogenesis and gliagenesis.
    Matched MeSH terms: Reverse Transcriptase Polymerase Chain Reaction/instrumentation; Reverse Transcriptase Polymerase Chain Reaction/methods*
  5. Zaman WS, Makpol S, Santhapan S, Chua KH
    Med J Malaysia, 2008 Jul;63 Suppl A:61-2.
    PMID: 19024984
    It is crucial to know whether stem cells retain its stemnness properties after advance in vitro manipulation. The objective of this study was to investigate the stemness gene expression of human adipose tissue derived stem cells (ADSCs) in long-term culture using quantitative RT-PCR technique. Our data showed that the expression level of Sox-2, Rex-1, FGF-4, Nanog, Nestin, BST-1, FZD-9 and Oct-4 were decreased gradually in long-term culture. This could mean that the ability of ADSCs to differentiate into other cell lineages reduce after extensive culture.
    Matched MeSH terms: Reverse Transcriptase Polymerase Chain Reaction
  6. Suriya R, Hassan L, Omar AR, Aini I, Tan CG, Lim YS, et al.
    Zoonoses Public Health, 2008 Sep;55(7):342-51.
    PMID: 18667027 DOI: 10.1111/j.1863-2378.2008.01138.x
    Following a series of H5N1 cases in chickens and birds in a few states in Malaysia, there was much interest in the influenza A viruses subtypes that circulate among the local pig populations. Pigs may act as a mixing vessel for avian and mammal influenza viruses, resulting in new reassorted viruses. This study investigated the presence of antibodies against influenza H1N1 and H3N2 viruses in pigs from Peninsular Malaysia using Herdcheck Swine Influenza H1N1 and H3N2 Antibody Test Kits. At the same time, the presence of influenza virus was examined from the nasal swabs of seropositive pigs by virus isolation and real time RT-PCR. The list of pig farms was obtained from the headquarters of the Department of Veterinary Services, Malaysia, and pig herds were selected randomly from six of 11 states in Peninsular Malaysia. A total of 727 serum and nasal swab samples were collected from 4- to 6-month-old pigs between May and August 2005. By ELISA, the seroprevalences of swine influenza H1N1 and H3N2 among pigs were 12.2% and 12.1% respectively. Seropositivity for either of the virus subtypes was detected in less than half of the 41 sampled farms (41.4%). Combination of both subtypes was detected in 4% of all pigs and in 22% of sampled farms. However, no virus or viral nucleic acid was detected from nasal samples. This study identified that the seropositivity of pigs to H1N1 and H3N2 based on ELISA was significantly associated with factors such as size of farm, importation or purchase of pigs, proximity of farm to other pig farms and the presence of mammalian pets within the farm.
    Matched MeSH terms: Reverse Transcriptase Polymerase Chain Reaction
  7. Omidvar V, Siti Nor Akmar A, Marziah M, Maheran AA
    Plant Cell Rep, 2008 Sep;27(9):1451-9.
    PMID: 18563415 DOI: 10.1007/s00299-008-0565-2
    The promoter of the oil palm metallothionein-like gene (MT3-A) demonstrated mesocarp-specific activity in functional analysis using transient expression assay of reporter gene in bombarded oil palm tissue slices. In order to investigate the tissue-specific expression of polyhydroxybutyrate (PHB) biosynthetic pathway genes, a multi-gene construct carrying PHB genes fused to the oil palm MT3-A promoter was co-transferred with a construct carrying GFP reporter gene using microprojectile bombardment targeting the mesocarp and leaf tissues of the oil palm. Transcriptional analysis using RT-PCR revealed successful transcription of all the three phbA, phbB, and phbC genes in transiently transformed mesocarp but not in transiently transformed leaf tissues. Furthermore, all the three expected sizes of PHB-encoded protein products were only detected in transiently transformed mesocarp tissues on a silver stained polyacrylamide gel. Western blot analysis using polyclonal antibody specific for phbB product confirmed successful translation of phbB mRNA transcript into protein product. This study provided valuable information, supporting the future engineering of PHB-producing transgenic palms.
    Matched MeSH terms: Reverse Transcriptase Polymerase Chain Reaction
  8. Foo LH, Suzina AH, Azlina A, Kannan TP
    J Biomed Mater Res A, 2008 Oct;87(1):215-21.
    PMID: 18085658
    Coral matrix of Porites sp. has the suitable properties for bone cell growth. This study was aimed to study the gene expression levels of osteoblast specific genetic markers; RUNX2, osteopontin, alkaline phosphatase and osteocalcin from osteoblasts seeded in coral scaffold, which are important in determining the feasibility of osteoblasts. Human osteoblasts were inoculated onto the processed coral in Dulbecco's Minimum Essential Medium. The cells were trypsinized on day 1, 7, 14, 18, and 21 and added with RNALater for preservation of RNA in cells. The RNA was extracted using commercial RNA extraction kit and the respective genes were amplified using RT-PCR kit and analyzed qualitatively on 1.5% agarose gel. The expressions were evaluated with the Integrated Density Value based on the intensity of band for different periods of cell harvest. Increased expressions of the RUNX2, osteopontin, alkaline phosphatase and osteocalcin genes in the present study proved that coral is a favorable carrier for osteogenetically competent cells to attach and remain viable.
    Matched MeSH terms: Reverse Transcriptase Polymerase Chain Reaction
  9. Eshkoor SA, Ismail P, Rahman SA, Oshkour SA
    Arch Med Res, 2008 Oct;39(7):668-73.
    PMID: 18760195 DOI: 10.1016/j.arcmed.2008.06.003
    Basal cell carcinoma (BCC) develops predominantly in sun-exposed skin in fair-skinned individuals prone to sunburn. BCC typically occurs in adults. High exposure to ultraviolet (UV) radiation increases rate of developing BCC, a slowly growing tumor that occurs in hair-growing squamous epithelium and rarely metastasizes. In genetic studies, BCC patients have cell-cycle abnormalities of different parts of the signaling pathway. Retinoblastoma regulatory pathway is important in cell cycle arrest. In this pathway, p16INK4a, an inhibitor of Rb pathway, binds to CDK4 and CDK6 competitively with cyclin D1 to prevent phosphorylation of tumor suppressor pRB gene. Alteration of this pathway contributes to development of human cancers and also is effective in skin cancers. In this study, we analyzed mRNA expression using in situ RT-PCR and the role of immunohistochemical expression of p16INK4a in BCC.
    Matched MeSH terms: Reverse Transcriptase Polymerase Chain Reaction
  10. Lee CY, Ng LC, Koh TH
    Singapore Med J, 2008 Nov;49(11):959-60.
    PMID: 19037568
    Matched MeSH terms: Reverse Transcriptase Polymerase Chain Reaction
  11. Low CF, Chong PP, Yong PV, Lim CS, Ahmad Z, Othman F
    J Appl Microbiol, 2008 Dec;105(6):2169-77.
    PMID: 19120662 DOI: 10.1111/j.1365-2672.2008.03912.x
    The aims of the present study were to determine whether Allium sativum (garlic) extract has any effect on the morphology transformation of Candida albicans, and to investigate whether it could alter the gene expression level of SIR2, a morphogenetic control gene and SAP4, a gene encoding secreted aspartyl proteinase.
    Matched MeSH terms: Reverse Transcriptase Polymerase Chain Reaction
  12. Rozitah R, Nizam MZ, Nur Shafawati AR, Nor Atifah MA, Dewi M, Kannan TP, et al.
    Singapore Med J, 2008 Dec;49(12):1046-9.
    PMID: 19122960
    Beta-thalassaemia major is an autosomal recessive disorder that results in severe microcytic, hypochromic, haemolytic anaemia among affected patients. Beta-thalassaemia has emerged as one of the most common public health problems in Malaysia, particularly among Malaysian Chinese and Malays. This study aimed to observe the spectrum of mutations found in Kelantan Malay beta-thalassaemia major patients who attended the Paediatrics Daycare Unit, Hospital Universiti Sains Malaysia, Kelantan, Malaysia, the data of which was being used in establishing the prenatal diagnosis in this Human Genome Centre.
    Matched MeSH terms: Reverse Transcriptase Polymerase Chain Reaction
  13. Jiang J, Ridley AW, Tang H, Croft BJ, Johnson KN
    Arch Virol, 2008;153(5):839-48.
    PMID: 18299794 DOI: 10.1007/s00705-008-0058-1
    Fiji leaf gall is an important disease of sugarcane in Australia and other Asia-Pacific countries. The causative agent is the reovirus Fiji disease virus (FDV). Previous reports indicate that there is variation in pathology between virus isolates. To investigate the amount of genetic variation found in FDV, 25 field isolates from Australia, Papua New Guinea and Malaysia were analysed by partial sequencing of genome segments S3 and S9. There was up to 15% divergence in the nucleotide sequence among the 25 isolates. A similar amount of divergence and pattern of relationships was found for each of the two genomic segments for most of the field isolates, although reassortment of genome segments seems likely for at least one of the Papua New Guinean isolates. The finding of a high level of variation in FDV isolated in different regions has implications for quarantine and disease management.
    Matched MeSH terms: Reverse Transcriptase Polymerase Chain Reaction
  14. Ibrahim K, Daud SS, Seah YL, Yeoh AE, Ariffin H, Malaysia-Singapore Leukemia Study Group
    Ann Clin Lab Sci, 2008;38(4):338-43.
    PMID: 18988926
    Childhood acute lymphoblastic leukaemia (ALL) is a heterogenous disease in which oncogene fusion transcripts are known to influence the biological behaviour of the different ALL subtypes. Screening for prognostically important transcripts is an important diagnostic step in treatment stratification and prognostication of affected patients. We describe a SYBR-Green real-time multiplex PCR assay to screen for transcripts TEL-AML1, E2A-PBX1, MLL-AF4, and the two breakpoints of BCR-ABL (p190 and p210). Validation of the assay was based on conventional karyotyping results. This new assay provides a rapid, sensitive, and accurate detection method for prognostically important transcripts in childhood ALL.
    Matched MeSH terms: Reverse Transcriptase Polymerase Chain Reaction/methods*
  15. Zulaikah Mohamed, Nazlina Ibrahim, Ismail Ahmad
    Sains Malaysiana, 2008;37(1):107-113.
    Methanol extract of Melastoma malabathricum leaves inhibited the growth of Staphylococcus aureus and six clinical isolates of Methicilin Resistant Stapyhlococcus aureus (MRSA 1-6). The minimum inhibitory concentration (MIC) of test substance was 1.565mg/ml and the minimum bacteriocidal concentration (MBC) was 3.125 mg/ml. The methanol extract suppressed RNA synthesis at 10 mg/ml as shown by RNA profile which was devoid of three bands compared to the control. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis using seven primer pairs was only successful in amplifying four cDNA amplicons. The failure to amplify three cDNA amplicons for three primer pairs corresponding to gyrA, femA and nuc genes, implied the possibility of suppression of the corresponding mRNA. Electrophoretic separation of endogenous and exogenuos bacterial proteins showed that three and five protein, respectively were not expressed. One endogenous and three exogenous proteins were over-expressed in treated MRSA compared with untreated control. The results of the molecular and proteomic analyses are in agreement, and based on primers being used, methanol extract of M. malabathricum leaves possibly inhibits MRSA growth through inhibition of DNA synthesis, peptidoglycan production, and nuclease production.
    Keywords: Methicillin resistant Staphylococcus aureus; Melastoma malabathricum; gene expression; protein production
    Matched MeSH terms: Reverse Transcriptase Polymerase Chain Reaction
  16. Skowronski DM, De Serres G, Dickinson J, Petric M, Mak A, Fonseca K, et al.
    J Infect Dis, 2009 Jan 15;199(2):168-79.
    PMID: 19086914 DOI: 10.1086/595862
    Trivalent inactivated influenza vaccine (TIV) is reformulated annually to contain representative strains of 2 influenza A subtypes (H1N1 and H3N2) and 1 B lineage (Yamagata or Victoria). We describe a sentinel surveillance approach to link influenza variant detection with component-specific vaccine effectiveness (VE) estimation.
    Matched MeSH terms: Reverse Transcriptase Polymerase Chain Reaction
  17. Rohani A, Potiwat R, Zamree I, Lee HL
    PMID: 19842428
    In this study, artificial membrane feeding technique was used to orally feed Aedes aegypti with dengue and chikungunya viruses. Virus detection was carried out by reverse transcriptase polymerase chain reaction. The study did not detect dual infection of Ae. aegypti with dengue and chikungunya virus from the same pool or from individual mosquitoes. Oral receptivity of Ae. aegypti to chikungunya virus was higher than that of dengue virus.
    Matched MeSH terms: Reverse Transcriptase Polymerase Chain Reaction
  18. Khong HK, Kuah MK, Jaya-Ram A, Shu-Chien AC
    PMID: 19272315 DOI: 10.1016/j.cbpb.2009.01.005
    Prolactin (PRL) has been shown to directly influence parental-care associated behavior in many vertebrate species. The discus fish (Symphysodon aequifasciata) displays extensive parental care behavior through utilization of epidermal mucosal secretion to raise free-swimming fry. Here, we cloned the full-length cDNA sequence of the S. aequifasciata prolactin receptor (dfPRLR) and investigated the mRNA expression pattern in several adult tissues. Bioinformatic analysis showed the dfPRLR shared rather high identity (79 and 67%) with the Nile tilapia PRLR 1 and black seabream PRLR 1, respectively. The presence of dfPRLR in several osmoregulatory tissues including kidney, gill and intestine is consistent with the known role of PRL in mediating hydromineral balance in teleosts. In addition, upregulated expression of PRLR mRNA was observed in skin of parental fish compared to non-parental fish, indicating possibility of a role of the PRL hormonal signaling in regulation of mucus production in relation to parental care behaviour.
    Matched MeSH terms: Reverse Transcriptase Polymerase Chain Reaction
  19. Kannan TP, Ali AQ, Abdullah SF, Ahmad A
    Food Chem Toxicol, 2009 Jul;47(7):1696-702.
    PMID: 19394390 DOI: 10.1016/j.fct.2009.04.020
    The aim of this study was to evaluate Tualang honey as a supplement to fetal bovine serum in cell cultures using MTT assay, chromosome aberration test and gene expression analyses. The MTT assay showed the highest percentage of cell proliferation (105.3% increment than control) of human osteoblast cell line (CRL 1543) in 0.0195% honey in Dulbecco's modified eagle medium supplemented with 10% fetal bovine serum and 1% penicillin/streptomycin. There was enhanced cell proliferation corresponding to the decrease in concentrations of honey as indicated by the mitotic index values when the osteoblast cell line was incubated at 37 degrees C for 48 hours. There were no chromosome aberrations both in the honey treated as well as distilled water treated (negative control) cell lines. In the case of gene expression analyses, fibroblast cell lines (CCL 171) were treated with honey (0.0195%) for 24 and 48 hours separately. Though there was over expression for the bcl-xl gene at both 24 and 48 hours, under expression for bcl-xs gene at 24 hours and over expression at 48 hours and under expression for both c-myc and p53 genes at both 24 and 48 hours, none of them were statistically significant in altering the expression of mRNA.
    Matched MeSH terms: Reverse Transcriptase Polymerase Chain Reaction
  20. Ortiz RH, Leon DA, Estevez HO, Martin A, Herrera JL, Romo LF, et al.
    Clin Exp Immunol, 2009 Aug;157(2):271-81.
    PMID: 19604267 DOI: 10.1111/j.1365-2249.2009.03941.x
    Buruli ulcer (BU) is the third most common mycobacterial disease in immunocompetent hosts. BU is caused by Mycobacterium ulcerans, which produces skin ulcers and necrosis at the site of infection. The principal virulence factor of M. ulcerans is a polyketide-derived macrolide named mycolactone, which has cytotoxic and immunosuppressive activities. We determined the severity of inflammation, histopathology and bacillary loads in the subcutaneous footpad tissue of BALB/c mice infected with 11 different M. ulcerans isolates from diverse geographical areas. Strains from Africa (Benin, Ghana, Ivory Coast) induced the highest inflammation, necrosis and bacillary loads, whereas the strains collected from Australia, Asia (Japan, Malaysia, New Guinea), Europe (France) and America (Mexico) induced mild inflammation. Subsequently, animals were infected with the strain that exhibited the highest (Benin) or lowest (Mexico) level of virulence in order to analyse the local immune response generated. The Mexican strain, which does not produce mycolactone, induced a predominantly T helper type 1 (Th1) cytokine profile with constant high expression of the anti-microbial peptides beta defensins 3 and 4, in co-existence with low expression of the anti-inflammatory cytokines interleukin (IL)-10, IL-4 and transforming growth factor (TGF)-beta. The highly virulent strain from Benin which produces mycolactone A/B induced the opposite pattern. Thus, different local immune responses were found depending on the infecting M. ulcerans strain.
    Matched MeSH terms: Reverse Transcriptase Polymerase Chain Reaction/methods
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