Displaying publications 621 - 640 of 1059 in total

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  1. Atroosh WM, Al-Mekhlafi HM, Mahdy MA, Saif-Ali R, Al-Mekhlafi AM, Surin J
    Parasit Vectors, 2011;4:233.
    PMID: 22166488 DOI: 10.1186/1756-3305-4-233
    Malaria is still a public health problem in Malaysia especially in the interior parts of Peninsular Malaysia and the states of Sabah and Sarawak (East Malaysia). This is the first study on the genetic diversity and genotype multiplicity of Plasmodium falciparum in Malaysia.
    Matched MeSH terms: Antigens, Protozoan/genetics*
  2. Lau YL, Fong MY, Mahmud R, Chang PY, Palaeya V, Cheong FW, et al.
    Malar J, 2011;10:197.
    PMID: 21774805 DOI: 10.1186/1475-2875-10-197
    The emergence of Plasmodium knowlesi in humans, which is in many cases misdiagnosed by microscopy as Plasmodium malariae due to the morphological similarity has contributed to the needs of detection and differentiation of malaria parasites. At present, nested PCR targeted on Plasmodium ssrRNA genes has been described as the most sensitive and specific method for Plasmodium detection. However, this method is costly and requires trained personnel for its implementation. Loop-mediated isothermal amplification (LAMP), a novel nucleic acid amplification method was developed for the clinical detection of P. knowlesi. The sensitivity and specificity of LAMP was evaluated in comparison to the results obtained via microscopic examination and nested PCR.
    Matched MeSH terms: Antigens, Protozoan/genetics
  3. Boo L, Selvaratnam L, Tai CC, Ahmad TS, Kamarul T
    J Mater Sci Mater Med, 2011 May;22(5):1343-56.
    PMID: 21461701 DOI: 10.1007/s10856-011-4294-7
    The use of mesenchymal stem cells (MSCs) in tissue repair and regeneration despite their multipotentiality has been limited by their cell source quantity and decelerating proliferative yield efficiency. A study was thus undertaken to determine the feasibility of using microcarrier beads in spinner flask cultures for MSCs expansion and compared to that of conventional monolayer cultures and static microcarrier cultures. Isolation and characterization of bone marrow derived MSCs were conducted from six adult New Zealand white rabbits. Analysis of cell morphology on microcarriers and culture plates at different time points (D0, D3, D10, D14) during cell culture were performed using scanning electron microscopy and bright field microscopy. Cell proliferation rates and cell number were measured over a period of 14 days, respectively followed by post-expansion characterization. MTT proliferation assay demonstrated a 3.20 fold increase in cell proliferation rates in MSCs cultured on microcarriers in spinner flask as compared to monolayer cultures (p < 0.05). Cell counts at day 14 were higher in those seeded on stirred microcarrier cultures (6.24 ± 0.0420 cells/ml) × 10(5) as compared to monolayer cultures (0.22 ± 0.004 cells/ml) × 10(5) and static microcarrier cultures (0.20 ± 0.002 cells/ml) × 10(5). Scanning electron microscopy demonstrated an increase in cell colonization of the cells on the microcarriers in stirred cultures. Bead-expanded MSCs were successfully differentiated into osteogenic and chondrogenic lineages. This system offers an improved and efficient alternative for culturing MSCs with preservation to their phenotype and multipotentiality.
    Matched MeSH terms: Antigens, CD29/metabolism
  4. Yeng C, Osman E, Mohamed Z, Noordin R
    Electrophoresis, 2010 Dec;31(23-24):3843-9.
    PMID: 21080484 DOI: 10.1002/elps.201000038
    Toxoplasma gondii infection in pregnant women may result in abortion and foetal abnormalities, and may be life-threatening in immunocompromised hosts. To identify the potential infection markers of this disease, 2-DE and Western blot methods were employed to study the parasite circulating antigens and host-specific proteins in the sera of T. gondii-infected individuals. The comparisons were made between serum protein profiles of infected (n=31) and normal (n=10) subjects. Antigenic proteins were identified by immunoblotting using pooled sera and monoclonal anti-human IgM-HRP. Selected protein spots were characterised using mass spectrometry. Prominent differences were observed when serum samples of T. gondii-infected individuals and normal controls were compared. A significant up-regulation of host-specific proteins, α(2)-HS glycoprotein and α(1)-B glycoprotein, was also observed in the silver-stained gels of both active and chronic infections. However, only α(2)-HS glycoprotein and α(1)-B glycoprotein in the active infection showed immunoreactivity in Western blots. In addition, three spots of T. gondii proteins were detected, namely (i) hypothetical protein chrXII: 3984434-3 TGME 49, (ii) dual specificity protein phosphatase, catalytic domain TGME 49 and (iii) NADPH-cytochrome p450 reductase TGME 49. Thus, 2-DE approach followed by Western blotting has enabled the identification of five potential infection markers for the diagnosis of toxoplasmosis: three are parasite-specific proteins and two are host-specific proteins.
    Matched MeSH terms: Antigens, Protozoan/blood*
  5. Kotresha D, Noordin R
    APMIS, 2010 Aug;118(8):529-42.
    PMID: 20666734 DOI: 10.1111/j.1600-0463.2010.02629.x
    Toxoplasma gondii is an important human pathogen with a worldwide distribution. It is primarily of medical importance for pregnant women and immunocompromised patients. Primary infection of the former is often associated with fetal infection, which can lead to abortion or severe neonatal malformation. Immunocompromised patients are at risk of contracting the severe form of the disease that may be fatal. Thus, detection of T. gondii infection with high sensitivity and specificity is crucial in the management of the disease. Toxoplasmosis is generally diagnosed by demonstrating specific immunoglobulin M (IgM) and IgG antibodies to toxoplasma antigens in the patient's serum sample. Most of the commercially available tests use T. gondii native antigens and display wide variations in test accuracy. Recombinant antigens have great potential as diagnostic reagents for use in assays to detect toxoplasmosis. Thus in this review, we address recent advances in the use of Toxoplasma recombinant proteins for serodiagnosis of toxoplasmosis.
    Matched MeSH terms: Antigens, Protozoan/immunology*
  6. Chang CC, Too CL, Murad S, Hussein SH
    Int J Dermatol, 2011 Feb;50(2):221-4.
    PMID: 21244392 DOI: 10.1111/j.1365-4632.2010.04745.x
    BACKGROUND: Carbamazepine (CBZ), a frequently used anticonvulsant drug, is one of the most common causes of life-threatening cutaneous adverse drug reactions such as toxic epidermal necrolysis (TEN) and Stevens-Johnson syndrome (SJS). Recent studies have revealed a strong association between HLA-B*1502 and CBZ-induced TEN/SJS in the Taiwan Han Chinese population.
    OBJECTIVES: This study is aimed to investigate the association between human leucocyte antigens (HLA) and CBZ-induced TEN/SJS in the multi-ethnic Malaysian population.
    METHODS: A sample of 21 unrelated patients with CBZ-induced TEN/SJS and 300 race-matched, healthy controls were genotyped for HLA-A, -B and -DR using polymerase chain reaction (PCR). Allele frequencies were compared.
    RESULTS: HLA-B*1502 was present in 75.0% (12/16) of Malay patients with CBZ-induced TEN/SJS but in only 15.7% (47/300) of normal controls (odds ratio 16.15, 95% confidence interval 4.57-62.4; corrected P-value  = 7.87 × 10(-6) ), which suggests a strong association between HLA and CBZ-induced TEN/SJS. Additionally, HLA-B*1502 was found in all three Chinese and two Indian patients. Existing data show that frequencies of the HLA-B*1502 allele are generally much higher in Asian populations than in White European populations, which explains the higher incidences of SJS and TEN in Asian countries.
    CONCLUSIONS: HLA-B*1502 is strongly associated with CBZ-induced TEN/SJS in the Malay population in Malaysia, as has been seen in Han Chinese in Taiwan. This indicates that the genetic association apparent in the incidence of CBZ-induced TEN/SJS is linked with the presence of HLA-B*1502, irrespective of racial origin. Screening of patients for this genetic marker can help to prevent the occurrence of TEN/SJS.
    Matched MeSH terms: HLA-B Antigens/genetics*
  7. Yap FL, Cheong SK, Ammu R, Leong CF
    Malays J Pathol, 2009 Dec;31(2):113-20.
    PMID: 20514854 MyJurnal
    In this study, we evaluated the biological properties of human mesenchymal stem cells transfected (hMSC) with a plasmid vector expressing human cytokine interleukin-12 (IL-12). Surface markers were analysed by immunophenotyping using flow cytometry. Differentiation capability was evaluated towards adipogenesis and osteogenesis. We demonstrated that successfully transfected hMSC retained their surface immunophenotypes and differentiation potential into adipocytes and osteocytes. These results indicate that hMSC may be a suitable vehicle for gene transduction.
    Matched MeSH terms: Antigens, Surface/metabolism
  8. Wong SF, Mak JW
    Hybridoma (Larchmt), 2010 Dec;29(6):539-46.
    PMID: 21117988 DOI: 10.1089/hyb.2010.0049
    Candida parapsilosis has emerged as one of the most common causes of bloodstream infection worldwide. The diagnosis of invasive candidiasis etiological agents to the species level remains a laboratory and clinical challenge. Thus, specific monoclonal antibodies to detect systemic candidiasis and to identify Candida virulence factors and associated pathogenesis through immunohistochemistry would be very useful. Inbred Balb/c mice were immunized with C. parapsilosis antigens, and blood was checked for the presence of reactive antibodies using ELISA. Fusion was performed using the harvested spleen cells and NS1 myeloma cells, and the clones were screened for the presence of antibody producing hybrid cells by dot-blot. The 1B11 clone secreted IgG2a monoclonal antibody that was reactive with the C. parapsilosis antigen at MW of 59 kDa and cross-reacted with C. tropicalis but not with other fungal and bacterial antigens tested. Another 3D1 clone secreted IgG1 monoclonal antibody that was reactive with C. parapsilosis antigen at MW of 30 kDa. The 3D1 monoclonal antibody was found to be species specific. Experimental systemic candidiasis in rats was induced through intravenous injection of C. parapsilosis, and all the vital organs were collected for immunohistochemistry study. These monoclonal antibodies were reactive against surface epitopes on the yeast cells, pseudohyphae, and immune complexes in tissue sections. Sandwich ELISAs using these antibodies were developed and were able to detect circulating antigens in experimental candidiasis in rats at 0.2 μg/μL. These monoclonal antibodies may have potential as primary capture antibodies for the development of rapid diagnostic test for human systemic fungal infection.
    Matched MeSH terms: Antigens, Fungal/immunology*
  9. Lim BK, Thong KL
    J Infect Dev Ctries, 2009 Jul 01;3(6):420-8.
    PMID: 19762954
    BACKGROUND: Differentiation of Salmonella enterica into its serogroups is important for epidemiological study. The objective of the study was to apply a multiplex PCR targeting serogroups A, B, C1, D, E and Vi-positive strains of Salmonella enterica commonly found in Malaysia. A separate H-typing multiplex PCR which identified flagellar antigen "a", "b" or "d" was also optimized to confirm clinical serotypes, S. Paratyphi A and S. Typhi.

    METHODOLOGY: Sixty-seven laboratory Salmonella enterica strains were tested. Six sets of primers targeting defined regions of the O antigen synthesis genes (rfb gene cluster) and Vi antigen gene (viaB) were selected and combined into a multiplex PCR for O-grouping. Four primers (H-for, Ha-rev, Hb-rev and Hd-rev) were used in the second step multiplex PCR for H-typing. The optimized mPCR assays were further evaluated with 58 blind-coded Salmonella strains.

    RESULTS: The multiplex PCR results obtained showed 100% concordance to the conventionally typed serogroups. Validation with 58 blind coded Salmonella strains yield 100% accuracy and specificity.

    CONCLUSION: Based on this study, PCR serogrouping proved to be a rapid, alternative method for further differentiation of Salmonella enterica.

    Matched MeSH terms: O Antigens/genetics
  10. Chandramathi S, Suresh K, Kuppusamy UR
    Parasitol Res, 2010 Mar;106(4):941-5.
    PMID: 20165878 DOI: 10.1007/s00436-010-1764-7
    Blastocystis hominis is one of the most common intestinal protozoan parasites in humans, and reports have shown that blastocystosis is coupled with intestinal disorders. In the past, researchers have developed an in vitro model using B. hominis culture filtrates to investigate its ability in triggering inflammatory cytokine responses and transcription factors in human colonic epithelial cells. Studies have also correlated the inflammation by parasitic infection with cancer. The present study provides evidence of the parasite facilitating cancer cell growth through observing the cytopathic effect, cellular immunomodulation, and apoptotic responses of B. hominis, especially in malignancy. Here we investigated the effect of solubilized antigen from B. hominis on cell viability, using peripheral blood mononuclear cells (PBMCs) and human colorectal carcinoma cells (HCT116). The gene expressions of cytokines namely interleukin 6 (IL-6), IL-8, tumor necrosis factor alpha, interferon gamma, nuclear factor kappa light-chain enhancer of activated B cells (a gene transcription factor), and proapoptotic genes namely protein 53 and cathepsin B were also studied. Results exhibited favor the fact that antigen from B. hominis, at a certain concentration, could facilitate the growth of HCT116 while having the ability to downregulate immune cell responses (PBMCs). Therefore, there is a vital need to screen colorectal cancer patients for B. hominis infection as it possesses the ability to enhance the tumor growth.
    Matched MeSH terms: Antigens, Protozoan/pharmacology*
  11. Tan SL, Sulaiman S, Pingguan-Murphy B, Selvaratnam L, Tai CC, Kamarul T
    Cell Tissue Bank, 2011 Feb;12(1):59-70.
    PMID: 19953328 DOI: 10.1007/s10561-009-9164-x
    This study investigates the feasibility of processed human amnion (HAM) as a substrate for chondrogenic differentiation of mesenchymal stem cells (MSCs). HAM preparations processed by air drying (AD) and freeze drying (FD) underwent histological examination and MSC seeding in chondrogenic medium for 15 days. Monolayer cultures were used as control for chondrogenic differentiation and HAMs without cell seeding were used as negative control. Qualitative observations were made using scanning electron microscopy analysis and quantitative analyses were based on the sulfated glycosaminoglycans (GAG) assays performed on day 1 and day 15. Histological examination of HAM substrates before seeding revealed a smooth surface in AD substrates, while the FD substrates exhibited a porous surface. Cell attachment to AD and FD substrates on day 15 was qualitatively comparable. GAG were significantly highly expressed in cells seeded on FD HAM substrates. This study indicates that processed HAM is a potentially valuable material as a cell-carrier for MSC differentiation.
    Matched MeSH terms: Antigens, CD44/metabolism
  12. Tong CK, Seow HF, Ramasamy R
    Med J Malaysia, 2008 Jul;63 Suppl A:77-8.
    PMID: 19024992
    The immune modulatory properties of mesenchymal stem cell (MSC) had brought a new insight in cell-based neotherapy. However, recent works of MSC are focused exclusively on bone marrow-derived MSC. We evaluated the immunogenicity of cord blood-derived MSC (CB-MSC) on T lymphocytes. Human peripheral blood mononuclear cells (PBMC) were prepared by density gradient separation and culture with the presence or absence of CB-MSC. PBMC were collected for activation analysis by flow cytometry at 24-, 48-, and 72- hours. The results showed that, CB-MSC does not stimulate nor inhibit T lymphocyte activation.
    Matched MeSH terms: Antigens, Differentiation, T-Lymphocyte; Antigens, CD
  13. Sasidharan S, Uyub AM
    J Immunoassay Immunochem, 2009;30(1):70-81.
    PMID: 19117203 DOI: 10.1080/15321810802569477
    Helicobacter pylori is recognized as a major case of gastritis and peptic ulcer and a key factor in the development of gastric cancer, gastric lymphoma, and non-ulcerative dyspepsia in man. The detection of antibodies specific for strains of H. pylori has demonstrated the value of serology for providing evidence of infection. The present study was conducted to detect the antigenic proteins of excretory antigen of H. pylori with Western blotting and examine whether anti-H. pylori IgG and IgA antibodies from H. pylori positive patients cross-react with antigens from other common bacterial pathogens. By using SDS-PAGE, 20 different proteins were found in the excretory antigen. By Western blotting and absorption studies, there were indications that anti-H. pylori IgA antibodies directed against 54 kDa, 50 kDa and 27 kDa cross-reacted with antigens from other bacteria, and that H. pylori proteins of 99 kDa, 88 kDa and 81 kDa possibly shared similar epitope with antigens of other pathogens not tested in the absorption studies. The cross-reactivity occurred in this study was not significantly affect the performance of the in-house ELISA.
    Matched MeSH terms: Antigens, Bacterial/immunology*
  14. Shiran MS, Tan GC, Arunachalam N, Sabariah AR, Pathmanathan R
    Malays J Pathol, 2006 Dec;28(2):113-6.
    PMID: 18376801
    We report a case of clear cell "sugar" tumour of the lung (CCTL) occurring in a 26-year-old lady. The patient was asymptomatic and the lesion was picked up in the course of a pre-employment medical examination. A well-defined 5 cm nodule in the right lower lobe was detected on routine chest X-Ray. Microscopical examination of the coin lesion showed clear cells containing abundant diastase-sensitive intracytoplasmic glycogen, as demohstrated with periodic acid-Schiff stains. Tumour immunoreactivity for HMB-45 and non-reactivity for cytokeratin support the histological diagnosis. To our knowledge, this is the first reported case of CCTL in Malaysia.
    Matched MeSH terms: Antigens, Neoplasm; Melanoma-Specific Antigens
  15. Thong KL, Tang SS, Tan WS, Devi S
    Microbiol. Immunol., 2007;51(11):1045-52.
    PMID: 18037781
    Polyclonal sera from typhoid patients and a monoclonal antibody, mAb ATVi, which recognizes the capsular polysaccharide Vi antigen (ViCPS), were used to select for peptides that mimic the ViCPS by using a phage-displayed random 12-mer peptide library. Two major common mimotopes selected from the library carried the amino acid sequences TSHHDSHGLHRV and ENHSPVNIAHKL. Enzyme-linked immunosorbent assays (ELISAs) showed that these peptides carry mimotopes to ViCPS. Phage clones that contained the 12-mer peptides were also tested against pooled/individual typhoid patients' sera and found to have 3 to 5 times higher binding compared to normal sera. By using Phage-ELISA assays, the derived synthetic peptides, TSHHDSHGLHRV and ENHSPVNIAHKL, were tested against a monoclonal antibody mAb ATVi and over 2-fold difference in binding was found between these peptides and a control unrelated peptide, CTLTTKLYC. Inhibition of the mAb's binding to ViCPS indicated that the synthetic peptides successfully competed with the capsular polysaccharide for antibody binding.
    Matched MeSH terms: Antigens, Bacterial/immunology*
  16. Kong NC, Beran J, Kee SA, Miguel JL, Sánchez C, Bayas JM, et al.
    Kidney Int, 2008 Apr;73(7):856-62.
    PMID: 18160963
    Prehemodialysis and hemodialysis patients are at an increased risk of hepatitis B infection and have an impaired immune response to hepatitis B vaccines. We evaluated the immune response to the new adjuvant of hepatitis B vaccine AS04 (HBV-AS04) in this population. We measured antibody persistence for up to 42 months, and the anamnestic response and safety of booster doses in patients who were no longer seroprotected. The primary vaccination study showed that HBV-AS04 elicited an earlier antibody response and higher antibody titers than four double doses of standard hepatitis B vaccine. Seroprotection rates were significantly higher in HBV-AS04 recipients throughout the study. The decline in seroprotection over time was significantly less in the HBV-AS04 group with significantly fewer primed patients requiring a booster dose over the follow-up period. Solicited/unsolicited adverse events were rare following booster administration. Fifty-seven patients experienced a serious adverse event during the follow-up; none of which was vaccine related. When HBV-AS04 was used as the priming immunogen, the need for a booster dose occurred at a longer time compared to double doses of standard hepatitis B vaccine. Hence, in this population, the HBV-AS04 was immunogenic, safe, and well-tolerated both as a booster dose after HBV-AS04 or standard hepatitis B vaccine priming.
    Matched MeSH terms: Hepatitis B Surface Antigens/blood*
  17. Quek SC, Low PS, Saha N, Heng CK
    Ann. Hum. Genet., 2006 Nov;70(Pt 6):951-7.
    PMID: 17044869
    Factor VII (FVII) is an independent risk factor for coronary artery disease. Three polymorphisms of the factor VII gene (F7) were studied in a group of healthy newborns comprising 561 Chinese, 398 Malays and 226 Asian Indians from Singapore. The allele frequencies of 3 polymorphisms (R353Q, Promoter 0/10bp Del/Ins and Intron 7) in the FVII gene were ascertained through genotyping by polymerase chain reaction and restriction digestion of amplified fragments. In Chinese the minor allele frequencies are Q: 0.04, Ins: 0.03, R7: 0.44; Malays, Q: 0.06, Ins: 0.10, R7: 0.41; and Indians, Q: 0.25, Ins: 0.23, R7: 0.43. Strong linkage disequilibrium (Delta > 0.7) is observed between the 0/10 bp and the R353Q sites in all ethnic groups. We conclude that: (i) the prevalence of the minor Q and Ins alleles of the R353Q and 0/10 bp polymorphisms are significantly higher in the Indian newborns than the Chinese and Malays; (ii) the Q allele is significantly associated (p = 0.01) with a lower plasma FVII coagulant level in the Indian and Malay neonates; and this polymorphism explains up to 3.8% of the variance in FVII coagulant levels; (iii) there is no significant difference in allele frequencies of the three polymorphisms between neonates with and without family histories of CAD.
    Matched MeSH terms: Antigens/blood*
  18. Chai HC, Phipps ME, Othman I, Tan LP, Chua KH
    Lupus, 2013 Feb;22(2):198-204.
    PMID: 23257407 DOI: 10.1177/0961203312470183
    BACKGROUND: Human leukocyte antigen (HLA) antigens and genes have long been reported associated with systemic lupus erythematosus (SLE) susceptibility in many populations. With the advance in technologies such as genome-wide association studies, many newly discovered SLE-associated single-nucleotide polymorphisms (SNPs) have been reported in recent years. These include HLA-DRB1/HLA-DQA1 rs9271366 and HLA-DQB1/HLA-DQA2 rs9275328. Our aim was to investigate these SNPs in a Malaysian SLE cohort.
    MATERIALS AND METHODS: SNPs rs9271366 and rs9275328 were screened across 790 Malaysian citizens from three ethnic groups (360 patients and 430 healthy volunteers) by Taqman SNP genotyping assays. Allele and genotyping frequencies, Hardy-Weinberg equilibrium, Fisher's exact test and odds ratio were calculated for each SNP and ethnic group. Linkage disequilibrium and interaction between the two SNPs were also evaluated.
    RESULTS: The minor allele G and its homozygous genotype GG of HLA-DRB1/HLA-DQA1 rs9271366 significantly increased the SLE susceptibility in Malaysian patients, including those of Malay and Chinese ethnicity (odds ratio (OR) > 1, p 
    Matched MeSH terms: HLA-DQ Antigens/genetics*
  19. Noraidah M, Jasmi AY
    Malays J Pathol, 2003 Jun;25(1):57-61.
    PMID: 16196379
    Malignant melanoma involving the gastrointestinal tract is diagnosed antemortem in only a small percentage of patients with the disease. Presenting symptoms are often non-specific, causing a diagnostic problem. The vast majority of such melanomas are metastatic from a cutaneous primary, however there is evidence that the tumour can arise de novo in the gastrointestinal system. We report a 74-year-old man with malignant melanoma with an unusual presentation simulating a symptomatic gastric ulcer. He presented with epigastric pain, haematemesis and melaena. Explorative laparotomy revealed a large ulcerated tumour with several pigmented satellite nodules in the proximal stomach, multiple ileal nodules and widespread nodal and liver metastases. Proximal gastrectomy and limited small bowel resection was performed. Histology revealed the tumour to be composed of nests of epithelioid cells with melanin pigment. The tumour cells showed immunohistochemical positivity for S100 protein and HMB45 antibodies. This report emphasizes that melanoma should be a diagnostic consideration in patients with gastric ulcer.
    Matched MeSH terms: Antigens, Neoplasm; Melanoma-Specific Antigens
  20. Liu L, Mo Z, Liang Z, Zhang Y, Li R, Ong KC, et al.
    BMC Med, 2015;13:226.
    PMID: 26381232 DOI: 10.1186/s12916-015-0448-7
    To investigate the long-term effects on immunity of an inactivated enterovirus 71 (EV71) vaccine and its protective efficacy.
    Matched MeSH terms: Antigens, Viral/immunology
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