Displaying publications 101 - 120 of 255 in total

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  1. Fulltext Cytotoxic effect of ethanol extract of microalga, Chaetoceros calcitrans, and its mechanisms in inducing apoptosis in human breast cancer cell line
    Ebrahimi Nigjeh S, Yusoff FM, Mohamed Alitheen NB, Rasoli M, Keong YS, Omar AR
    Biomed Res Int, 2013;2013:783690.
    PMID: 23509778 DOI: 10.1155/2013/783690
    Marine microalgae have been prominently featured in cancer research. Here, we examined cytotoxic effect and apoptosis mechanism of crude ethanol extracts of an indigenous microalga, Chaetoceros calcitrans (UPMAAHU10) on human breast cell lines. MCF-7 was more sensitive than MCF-10A with IC50 value of 3.00 ± 0.65, whilst the IC50 value of Tamoxifen against MCF-7 was 12.00 ± 0.52  μg/mL after 24 hour incubation. Based on Annexin V/Propidium iodide and cell cycle flow cytometry analysis, it was found that inhibition of cell growth by EEC on MCF-7 cells was through the induction of apoptosis without cell cycle arrest. The apoptotic cells at subG0/G1 phase in treated MCF-7 cells at 48 and 72 hours showed 34 and 16 folds increased compared to extract treated MCF-10A cells which showed only 6 and 7 folds increased at the same time points, respectively. Based on GeXP study, EEC induced apoptosis on MCF-7 cells via modulation of CDK2, MDM2, p21Cip1, Cyclin A2, Bax and Bcl-2. The EEC treated MCF-7 cells also showed an increase in Bax/Bcl-2 ratio that in turn activated the caspase-dependent pathways by activating caspase 7. Thus, marine microalga, Chaetoceros calcitrans may be considered a good candidate to be developed as a new anti-breast cancer drug.
  2. Goniothalamin selectively induces apoptosis on human hepatoblastoma cells through caspase-3 activation
    Al-Qubaisi M, Rosli R, Subramani T, Omar AR, Yeap SK, Ali AM, et al.
    Nat Prod Res, 2013;27(23):2216-8.
    PMID: 23767409 DOI: 10.1080/14786419.2013.800979
    Goniothalamin is a biologically active styrylpyrone derivative isolated from various Goniothalamus species. The ability of goniothalamin to induce apoptosis via caspase-3 activation against hepatoblastoma (HepG2) and normal liver cells (Chang cells) was studied using morphological and biochemical evaluations. HepG2 and Chang cells were treated with goniothalamin for 72 h and analysed by TUNEL and Annexin-V/PI staining. Furthermore, the post-mitochondrial caspase-3 was quantified using ELISA. In view of our results, goniothalamin induced apoptosis on treated cells via alteration of cellular membrane integrity and cleavage of DNA. On the other hand, post-mitochondrial caspase-3 activity was significantly elevated in HepG2 cells treated with goniothalamin after 72 h. These findings suggest that goniothalamin induced apoptosis on HepG2 liver cancer cells via induction of caspase-3 with less sensitivity on the cell line of Chang cells.
  3. Fulltext Rhaphidophora korthalsii modulates peripheral blood natural killer cell proliferation, cytokine secretion and cytotoxicity
    Yeap SK, Omar AR, Ho WY, Beh BK, Ali AM, Alitheen NB
    BMC Complement Altern Med, 2013;13:145.
    PMID: 23800124 DOI: 10.1186/1472-6882-13-145
    Rhaphidophora korthalsii (Araceae) is a root-climber plant which has been widely used in Chinese traditional medicine for cancer and skin disease treatment. Previous reports have recorded its immunomodulatory effects on mice splenocyte and human peripheral blood. This study investigated the potential immunostimulatory effect of Rhaphidophora korthalsii on human PBMC enriched NK cell.
  4. Fulltext Co-administration of avian influenza virus H5 plasmid DNA with chicken IL-15 and IL-18 enhanced chickens immune responses
    Lim KL, Jazayeri SD, Yeap SK, Alitheen NB, Bejo MH, Ideris A, et al.
    BMC Vet Res, 2012;8:132.
    PMID: 22866758 DOI: 10.1186/1746-6148-8-132
    DNA vaccines offer several advantages over conventional vaccines in the development of effective vaccines against avian influenza virus (AIV). However, one of the limitations of the DNA vaccine in poultry is that it induces poor immune responses. In this study, chicken interleukin (IL) -15 and IL-18 were used as genetic adjuvants to improve the immune responses induced from the H5 DNA vaccination in chickens. The immunogenicity of the recombinant plasmid DNA was analyzed based on the antibody production, T cell responses and cytokine production, following inoculation in 1-day-old (Trial 1) and 14-day-old (Trial 2) specific-pathogen-free chickens. Hence, the purpose of the present study was to explore the role of chicken IL-15 and IL-18 as adjuvants following the vaccination of chickens with the H5 DNA vaccine.
  5. Cytotoxicity and immunological responses following oral vaccination of nanoencapsulated avian influenza virus H5 DNA vaccine with green synthesis silver nanoparticles
    Jazayeri SD, Ideris A, Zakaria Z, Shameli K, Moeini H, Omar AR
    J Control Release, 2012 Jul 10;161(1):116-23.
    PMID: 22549012 DOI: 10.1016/j.jconrel.2012.04.015
    DNA formulations provide the basis for safe and cost effective vaccine. Low efficiency is often observed in the delivery of DNA vaccines. In order to assess a new strategy for oral DNA vaccine formulation and delivery, plasmid encoding hemagglutinin (HA) gene of avian influenza virus, A/Ck/Malaysia/5858/04 (H5N1) (pcDNA3.1/H5) was formulated using green synthesis of sliver nanoparticles (AgNP) with polyethylene glycol (PEG). AgNP were successfully synthesized uniformly dispersed with size in the range of 4 to 18 nm with an average size of 11 nm. Cytotoxicity of the prepared AgNP was investigated in vitro and in vivo using MCF-7 cells and cytokine expression, respectively. At the concentration of -5 log₁₀AgNP, no cytotoxic effects were detected in MCF-7 cells with 9.5% cell death compared to the control. One-day-old specific pathogen-free (SPF) chicks immunized once by oral gavage with 10 μl of pcDNA3.1/H5 (200 ng/ml) nanoencapsulated with 40 μl AgNP (3.7×10⁻² μg of Ag) showed no clinical manifestations. PCR successfully detect the AgNP/H5 plasmid from the duodenum of the inoculated chicken as early as 1h post-immunization. Immunization of chickens with AgNP/H5 enhanced both pro inflammatory and Th1-like expressions, although no significant differences were recorded in the chickens inoculated with AgNP, AgNP/pcDNA3.1 and the control. In addition, serum samples collected from immunized chickens with AgNP/H5 showed rapidly increasing antibody against H5 on day 14 after immunization. The highest average antibody titres were detected on day 35 post-immunization at 51.2±7.5. AgNP/H5 also elicited both CD4+ and CD8+ T cells in the immunized chickens as early as day 14 after immunization, at 7.5±2.0 and 20±1.9 percentage, respectively. Hence, single oral administrations of AgNP/H5 led to induce both the antibody and cell-mediated immune responses as well as enhanced cytokine production.
  6. Fulltext Cellular transcripts of chicken brain tissues in response to H5N1 and Newcastle disease virus infection
    Balasubramaniam VR, Wai TH, Omar AR, Othman I, Hassan SS
    Virol J, 2012;9:53.
    PMID: 22361110 DOI: 10.1186/1743-422X-9-53
    Highly-pathogenic avian influenza (HPAI) H5N1 and Newcastle disease (ND) viruses are the two most important poultry viruses in the world, with the ability to cause classic central nervous system dysfunction in poultry and migratory birds. To elucidate the mechanisms of neurovirulence caused by these viruses, a preliminary study was design to analyze host's cellular responses during infections of these viruses.
  7. Improved immune responses against avian influenza virus following oral vaccination of chickens with HA DNA vaccine using attenuated Salmonella typhimurium as carrier
    Jazayeri SD, Ideris A, Zakaria Z, Yeap SK, Omar AR
    Comp Immunol Microbiol Infect Dis, 2012 Sep;35(5):417-27.
    PMID: 22512819 DOI: 10.1016/j.cimid.2012.03.007
    This study evaluates the immune responses of single avian influenza virus (AIV) HA DNA vaccine immunization using attenuated Salmonella enterica sv. Typhimurium as an oral vaccine carrier and intramuscular (IM) DNA injection. One-day-old specific-pathogen-free (SPF) chicks immunized once by oral gavage with 10(9) Salmonella colony-forming units containing plasmid expression vector encoding the HA gene of A/Ck/Malaysia/5858/04 (H5N1) (pcDNA3.1.H5) did not show any clinical manifestations. Serum hemagglutination inhibition (HI) titer samples collected from the IM immunized chickens were low compared to those immunized with S. typhimurium.pcDNA3.1.H5. The highest average antibody titers were detected on day 35 post immunization for both IM and S. typhimurium.pcDNA3.1.H5 immunized groups, at 4.0±2.8 and 51.2±7.5, respectively. S. typhimurium.pcDNA3.1.H5 also elicited both CD4(+) and CD8(+) T cells from peripheral blood mononuclear cells (PBMCs) of immunized chickens as early as day 14 after immunization, at 20.5±2.0 and 22.9±1.9%, respectively. Meanwhile, the CD4(+) and CD8(+) T cells in chickens vaccinated intramuscularly were low at 5.9±0.9 and 8.5±1.3%, respectively. Immunization of chickens with S. typhimurium.pcDNA3.1.H5 enhanced IL-1β, IL-12β, IL-15 and IL-18 expressions in spleen although no significant differences were recorded in chickens vaccinated via IM and orally with S. typhimurium and S. typhimurium.pcDNA3.1. Hence, single oral administrations of the attenuated S. typhimurium containing pcDNA3.1.H5 showed antibody, T cell and Th1-like cytokine responses against AIV in chickens. Whether the T cell response induced by vaccination is virus-specific and whether vaccination protects against AIV infection requires further study.
  8. 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.
  9. Effect of culture media on expansion properties of human umbilical cord matrix-derived mesenchymal cells
    Salehinejad P, Alitheen NB, Nematollahi-Mahani SN, Ali AM, Omar AR, Janzamin E, et al.
    Cytotherapy, 2012 Sep;14(8):948-53.
    PMID: 22587592 DOI: 10.3109/14653249.2012.684377
    BACKGROUND AIMS: Mesenchymal stromal cells (MSC) have been isolated from a number of different tissues, including umbilical cord. Because of the lack of a uniform approach to human umbilical cord matrix-derived mesenchymal (hUCM) cell expansion, we attempted to identify the optimum conditions for the production of a high quantity of hUCM cells by comparing two media.

    METHODS: We compared the ability of Dulbecco's Modified Eagle's Medium/F12 (DMEM/F12) and Alpha Minimum Essential Medium (α-MEM) with Glutamax (GL) (α-MEM/GL) to expand hUCM cells. For this purpose, hUCM cells were cultured in plates containing different culture media supplemented with 10% fetal bovine serum (FBS). Culture dishes were left undisturbed for 10-14 days to allow propagation of the newly formed hUCM cells. The expansion properties, CD marker expression, differentiation potential, population doubling time (PDT) and cell activity were compared between the two groups.

    RESULTS: The hUCM cells harvested from each group were positive for MSC markers, including CD44, CD90 and CD105, while they were negative for the hematopoietic cell surface marker CD34. Differentiation into adipogenic and osteogenic lineages was confirmed for both treatments. Cell activity was higher in the α-MEM/GL group than the DMEM/F12 group. PDT was calculated to be 60 h for the DMEM/F12 group, while for the α-MEM/GL group it was 47 h.

    CONCLUSIONS: Our data reveal that α-MEM/GL with 10% FBS supports hUCM cell growth more strongly than DMEM/F12 with 10% FBS.

  10. Fulltext Effects of newcastle disease virus strains AF2240 and V4-UPM on cytolysis and apoptosis of leukemia cell lines
    Alabsi AM, Bakar SA, Ali R, Omar AR, Bejo MH, Ideris A, et al.
    Int J Mol Sci, 2011;12(12):8645-60.
    PMID: 22272097 DOI: 10.3390/ijms12128645
    Newcastle disease virus (NDV) is used as an antineoplastic agent in clinical tumor therapy. It has prompted much interest as an anticancer agent because it can replicate up to 10,000 times better in human cancer cells than in most normal cells. This study was carried out to determine the oncolytic potential of NDV strain AF2240 and V4-UPM on WEHI-3B leukemia cell line. Results from MTT cytotoxicity assay showed that the CD(50) values for both strains were 2 and 8 HAU for AF2240 and V4-UPM, respectively. In addition, bromodeoxyuridine (BrdU) and trypan blue dye exclusion assays showed inhibition in cell proliferation after different periods. Increase in the cellular level of caspase-3 and detection of DNA laddering using agarose gel electrophoresis on treated cells with NDV confirmed that the mode of cell death was apoptosis. In addition, flow-cytometry analysis of cellular DNA content showed that the virus caused an increase in the sub-G1 region (apoptosis peaks). In conclusion, NDV strains AF2240 and V4-UPM caused cytolytic effects against WEHI-3B leukemic cell line.
  11. Anti-leukemic activity of Newcastle disease virus strains AF2240 and V4-UPM in murine myelomonocytic leukemia in vivo
    Alabsi AM, Ali R, Ideris A, Omar AR, Bejo MH, Yusoff K, et al.
    Leuk. Res., 2012 May;36(5):634-45.
    PMID: 22133641 DOI: 10.1016/j.leukres.2011.11.001
    Newcastle disease virus (NDV) is a member of the Paramyxoviridae that has caused severe economic losses in poultry industry worldwide. Several strains of NDV were reported to induce cytolysis to cancerous cell lines. It has prompted much interest as anticancer agent because it can replicate up to 10,000 times better in human cancer cells than in most normal cells. In this study, two NDV strains, viserotropic-velogenic strain AF2240 and lentogenic strain V4-UPM, showed cytolytic activity and apoptosis induction against Mouse myelomoncytic leukemia (WEHI 3B). The cytolytic effects of NDV strains were determined using microtetrazolium (MTT) assay. The cytolytic dose - fifty percent (CD(50)) were 2 and 8HAU for AF2240 and V4-UPM strains, respectively. Cells treated with NDV strains showed apoptotic features compared to the untreated cells under fluorescence microscope. NDV induced activation of caspase-3 and DNA laddering in agarose gel electrophoresis which confirmed the apoptosis. The anti-leukemic activity of both strains was evaluated on myelomoncytic leukemia BALB/c mice. The results indicated that both NDV strains significantly decreased liver and spleen weights. It also decreased blasts cell percentage in blood, bone marrow and spleen smears of treated mice (p<0.05). Histopathological studies for spleen and liver confirmed the hematological results of blood and bone marrow. From the results obtained, the exposure to both NDV stains AF2240 and V4-UPM showed similar results for Ara-c. In conclusion NDV strains AF2240 and V4-UPM can affect WEHI 3B leukemia cells in vitro and in vivo.
  12. Fulltext Cellular transcripts regulated during infections with Highly Pathogenic H5N1 Avian Influenza virus in 3 host systems
    Balasubramaniam VR, Hassan SS, Omar AR, Mohamed M, Noor SM, Mohamed R, et al.
    Virol J, 2011;8:196.
    PMID: 21529348 DOI: 10.1186/1743-422X-8-196
    Highly pathogenic Avian Influenza (HPAI) virus is able to infect many hosts and the virus replicates in high levels in the respiratory tract inducing severe lung lesions. The pathogenesis of the disease is actually the outcome of the infection as determined by complex host-virus interactions involving the functional kinetics of large numbers of participating genes. Understanding the genes and proteins involved in host cellular responses are therefore, critical for the elucidation of the mechanisms of infection.
  13. Fulltext Selective cytotoxicity of goniothalamin against hepatoblastoma HepG2 cells
    Al-Qubaisi M, Rozita R, Yeap SK, Omar AR, Ali AM, Alitheen NB
    Molecules, 2011 Apr 06;16(4):2944-59.
    PMID: 21471934 DOI: 10.3390/molecules16042944
    Liver cancer has become one of the major types of cancer with high mortality and liver cancer is not responsive to the current cytotoxic agents used in chemotherapy. The purpose of this study was to examine the in vitro cytotoxicity of goniothalamin on human hepatoblastoma HepG2 cells and normal liver Chang cells. The cytotoxicity of goniothalamin against HepG2 and liver Chang cell was tested using MTT cell viability assay, LDH leakage assay, cell cycle flow cytometry PI analysis, BrdU proliferation ELISA assay and trypan blue dye exclusion assay. Goniothalamin selectively inhibited HepG2 cells [IC₅₀ = 4.6 (±0.23) µM in the MTT assay; IC₅₀ = 5.20 (±0.01) µM for LDH assay at 72 hours], with less sensitivity in Chang cells [IC₅₀ = 35.0 (±0.09) µM for MTT assay; IC₅₀ = 32.5 (±0.04) µM for LDH assay at 72 hours]. In the trypan blue dye exclusion assay, the Viability Indexes were 52 ± 1.73% for HepG2 cells and 62 ± 4.36% for Chang cells at IC₅₀ after 72 hours. Cytotoxicity of goniothalamin was related to inhibition of DNA synthesis, as revealed by the reduction of BrdU incorporation. At 72 hours, the lowest concentration of goniothalamin (2.3 µL) retained 97.6% of normal liver Chang cells proliferation while it reduced HepG2 cell proliferation to 19.8% as compared to control. Besides, goniothalamin caused accumulation of hypodiploid apoptosis and different degree of G2/M arrested as shown in cell cycle analysis by flow cytometry. Goniothalamin selectively killed liver cancer cell through suppression of proliferation and induction of apoptosis. These results suggest that goniothalamin shows potential cytotoxicity against hepatoblastoma HepG2 cells.
  14. Fulltext Diagnostic methods for feline coronavirus: a review
    Sharif S, Arshad SS, Hair-Bejo M, Omar AR, Zeenathul NA, Alazawy A
    Vet Med Int, 2010;2010.
    PMID: 20798771 DOI: 10.4061/2010/809480
    Feline coronaviruses (FCoVs) are found throughout the world. Infection with FCoV can result in a diverse range of signs from clinically inapparent infections to a highly fatal disease called feline infectious peritonitis (FIP). FIP is one of the most serious viral diseases of cats. While there is neither an effective vaccine, nor a curative treatment for FIP, a diagnostic protocol for FCoV would greatly assist in the management and control of the virus. Clinical findings in FIP are non-specific and not helpful in making a differential diagnosis. Haematological and biochemical abnormalities in FIP cases are also non-specific. The currently available serological tests have low specificity and sensitivity for detection of active infection and cross-react with FCoV strains of low pathogenicity, the feline enteric coronaviruses (FECV). Reverse transcriptase polymerase chain reaction (RT-PCR) has been used to detect FCoV and is rapid and sensitive, but results must be interpreted in the context of clinical findings. At present, a definitive diagnosis of FIP can be established only by histopathological examination of biopsies. This paper describes and compares diagnostic methods for FCoVs and includes a brief account of the virus biology, epidemiology, and pathogenesis.
  15. Fulltext Development of avian influenza virus H5 DNA vaccine and MDP-1 gene of Mycobacterium bovis as genetic adjuvant
    Jalilian B, Omar AR, Bejo MH, Alitheen NB, Rasoli M, Matsumoto S
    Genet Vaccines Ther, 2010;8:4.
    PMID: 20497569 DOI: 10.1186/1479-0556-8-4
    Studies have shown that DNA vaccines can induce protective immunity, which demonstrated the high potential of DNA vaccines as an alternative to inactivated vaccines. Vaccines are frequently formulated with adjuvants to improve their release, delivery and presentation to the host immune system.
  16. Fulltext Identification and characterisation of a novel anti-viral peptide against avian influenza virus H9N2
    Rajik M, Jahanshiri F, Omar AR, Ideris A, Hassan SS, Yusoff K
    Virol J, 2009;6:74.
    PMID: 19497129 DOI: 10.1186/1743-422X-6-74
    Avian influenza viruses (AIV) cause high morbidity and mortality among the poultry worldwide. Their highly mutative nature often results in the emergence of drug resistant strains, which have the potential of causing a pandemic. The virus has two immunologically important glycoproteins, hemagglutinin (HA), neuraminidase (NA), and one ion channel protein M2 which are the most important targets for drug discovery, on its surface. In order to identify a peptide-based virus inhibitor against any of these surface proteins, a disulfide constrained heptapeptide phage display library was biopanned against purified AIV sub-type H9N2 virus particles.
  17. Sequence and phylogenetic analysis of Newcastle disease virus genotypes isolated in Malaysia between 2004 and 2005
    Tan SW, Ideris A, Omar AR, Yusoff K, Hair-Bejo M
    Arch Virol, 2010;155(1):63-70.
    PMID: 19898736 DOI: 10.1007/s00705-009-0540-4
    Sequence analysis of the fusion (F) gene of eight Malaysian NDV isolates showed that all the isolates were categorized as velogenic viruses, with the F cleavage site motif (112)R-R-Q-K-R(116) or (112)R-R-R-K-R(116) at the C-terminus of the F(2) protein and phenylalanine (F) at residue 117 at the N-terminus of the F(1) protein. Phylogenetic analysis revealed that all of the isolates were grouped in two distinct clusters under sub-genotype VIId. The isolates were about 4.8-11.7% genetically distant from sub-genotypes VIIa, VIIb, VIIc and VIIe. When the nucleotide sequences of the eight Malaysian isolates were compared phylogenetically to those of the old published local isolates, it was found that genotype VIII, VII, II and I viruses exist in Malaysia and caused sporadic infections. It is suggested that genotype VII viruses were responsible for most of the outbreaks in recent years.
  18. Seroprevalence and risk factors for influenza A viruses in pigs in Peninsular Malaysia
    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.
  19. Effect of Rhaphidophora korthalsii methanol extract on human peripheral blood mononuclear cell (PBMC) proliferation and cytolytic activity toward HepG2
    Yeap SK, Alitheen NB, Ali AM, Omar AR, Raha AR, Suraini AA, et al.
    J Ethnopharmacol, 2007 Dec 3;114(3):406-11.
    PMID: 17884317
    The study of bioactivity of natural product is one of the major researches for drug discovery. The aim of this finding was to study the proliferation effect of Rhaphidophora korthalsii methanol extract on human PBMC and subsequently the cytotoxic effect of activated PBMC toward HepG2 human hepatocellular carcinoma. In this present study, MTT assay, cell cycle study and Annexin 5 binding assay were used to study the immunomodulatory and cytotoxic effects. In vitro cytotoxic screening of Rhaphidophora korthalsii methanol extract showed that the extract was non-toxic against hepatocellular carcinoma (HepG2). In contrast, the extract was able to stimulate the proliferation of human PBMC at 48 h and 72 h in MTT assay and cell cycle progress study. The application of immunomodulator in tumor research was studied by using MTT microcytotoxicity assay and flow cytometric Annexin V. Results indicated that pre-treated PBMC with Rhaphidophora korthalsii methanol extract induced the highest cytotoxicity (44.87+/-6.06% for MTT microcytotoxicity assay and 51.51+/-3.85% for Annexin V) toward HepG2. This finding demonstrates that Rhaphidophora korthalsii methanol extract are potent to stimulate the cytotoxic effect of immune cells toward HepG2.
  20. Pathogenesis and antibody response to a cytomegalovirus infection in newborn rats
    Loh HS, Mohd-Azmi ML, Sheikh-Omar AR, Zamri-Saad M, Tam YJ
    Acta Virol., 2007;51(1):27-33.
    PMID: 17432941
    The present study described the kinetics of Rat cytomegalovirus (RCMV) infection in newborn rats by monitoring infectious virus and viral antigens in various organs, viral DNA in the blood (DNAemia) and antibody response. These parameters were evaluated quantitatively using double-antibody sandwich ELISA (DAS-ELISA), real-time PCR, indirect ELISA and virus infectivity assay. For the first time DAS-ELISA was used for detection of RCMV antigen directly from organ samples. The relationships between the presence of viral antigens in the infected organs and antibody levels were established by the Spearman's rank test. It was found that the virus was present in the blood, spleen, liver, lungs, and kidneys earlier than in the salivary glands. Furthermore, the early immunity of the newborn rats led to a delayed seroconversion. We suggested that the prolonged presence of the virus in salivary glands could augment the antibody response that conversely might be responsible for a reduction of viremia. This study expanded our understanding of RCMV pathogenesis leading to improved therapeutic and preventive treatment regimens particularly for the neonatal Human cytomegalovirus (HCMV) infections. Additionally, the detection procedures developed in this study such as DAS-ELISA and real-time PCR could serve as alternative techniques for rapid screening of large number of samples.
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