Displaying publications 1 - 20 of 27 in total

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  1. Antigenic comparisons of hog cholera virus isolates from Europe, America and Asia using monoclonal antibodies
    Edwards S, Sands JJ
    DTW. Dtsch. Tierarztl. Wochenschr., 1990 Feb;97(2):79-81.
    PMID: 2178905
    Nineteen monoclonal antibodies (MAbs) with specificity for hog cholera virus (HCV) were prepared. They were used in an immune binding (peroxidase linked) assay to determine the reaction patterns of HCV isolates from Europe, Brazil, USA, Japan and Malaysia, as well as laboratory reference strains of the virus. A further panel of 17 MAbs raised against bovine virus diarrhoea virus (BVDV) was included in the study, together with 5 MAbs raised against a non-HCV pestivirus of porcine origin. All the MAbs were also tested against representative strains of BVDV and border disease virus. Six MAbs were HCV-specific, reacting with all isolates of HCV and none of the ruminant viruses. Among the other HCV MAbs geographical variation in reaction patterns was observed. There was evidence of antigenic distinction between recent European isolates, and archive material originally isolated more than 10 years ago.
    Matched MeSH terms: Antigens, Viral/analysis*
  2. Comparison of direct immunoperoxidase and direct immunofluorescence for the detection of herpes simplex virus antigen in cell culture
    Sabil D, Othman SK, Isahak I
    Malays J Pathol, 1990 Jun;12(1):35-8.
    PMID: 1965320
    150 specimens from suspected herpes simplex genital and skin lesions were received in virus transport medium. They were inoculated into Hep-2 cell monolayers, examined for the presence of virus by cytopathic effect (CPE), direct immunoperoxidase (DIP) and direct immunofluorescence (DIF). Of 39 (26.0%) virus-positive specimens by CPE, 37 (24.7%) were HSV-positive by DIP and 36 (24.0%) by DIF staining. DIP staining had a sensitivity of 100%, specificity of 99.1%, positive predictive value of 97.3% and negative predictive value of 100% in relation to DIF as a standard test. Of 39 specimens positive by CPE, only 25.6% were HSV-positive within 24 h post-inoculation compared to 94% HSV-positive by DIP and DIF staining at the same time.
    Matched MeSH terms: Antigens, Viral/analysis*
  3. Fulltext Human papillomavirus DNA and virus-encoded antigens in cervical carcinoma
    Padmanathan A, Yadav M, Gregory AR, Kumar S, Norhanum AW
    Med J Malaysia, 1997 Jun;52(2):108-16.
    PMID: 10968067
    The present study was undertaken to evaluate the prevalence of HPV in formalin-fixed, paraffin-embedded cervical carcinoma tissues using PCR followed by non-radioactive Southern hybridization with type-specific oligonucleotides for HPV 16 and 18. In addition, the tissue sections were immunohistochemically screened with two monoclonal antibodies, for expression of HPV 16 L1 and HPV 18 E6 proteins. A total of 57 of 60 cervical carcinomas (95.0%) were found with HPV using both techniques. HPV 16 and HPV 18 were present in equal proportions. Results of both DNA hybridization and immunohistochemistry were in agreement for the majority of the cases. HPV 16 and 18 DNA and virus-encoded antigens, L1 and E6 were found highly prevalent in these cervical carcinomas. Due to the high prevalence of HPV with cervical carcinoma in Malaysia, the implementation of routine diagnosis for the virus in cervical biopsies would be clinically useful.
    Matched MeSH terms: Antigens, Viral/analysis*
  4. Improved sensitivity of detection by avidin-biotin complex (ABC) immunocytochemistry in Epstein-Barr virus serology
    Thoe SY, Sam CK, Cheng HM, Prasad U
    J Med Virol, 1989 Dec;29(4):311-4.
    PMID: 2559955
    Serum antibodies against Epstein-Barr virus (EBV)-determined antigens have traditionally been titrated by the indirect immunofluorescence (IIF) technique. The avidin-biotin complex (ABC) immunocytochemical technique was used to determine the serum levels of IgA against EBV viral capsid antigen (IgA/VCA) and IgA against EBV early antigen (IgA/EA) in sera of 106 nasopharyngeal carcinoma (NPC) patients prior to treatment and 100 normal individuals. The sensitivity of the ABC technique is enhanced by an amplification of the antigen-antibody reaction, which involves the binding of the enzyme-linked ABC to the second biotinylated antibody. There was a good correlation (r = 0.9988) between ABC and IIF-determined IgA/VCA-positive titres, with the ABC technique being more sensitive than IIF in the detection of IgA/VCA in NPC sera: 94% (99/106) and 76% (80/106), respectively. The frequency of IgA/EA reactivity in NPC sera was also markedly increased by immunodetection with the ABC technique as compared with IIF technique: 63% (69/106) and 28% (30/106) respectively. Both the immunocytochemical techniques were equally specific in discriminating between elevated serum titres of IgA/VCA and IgA/EA in NPC sera from normal human sera.
    Matched MeSH terms: Antigens, Viral/analysis*
  5. Attenuation of virulence of flaviviruses following passage in HeLa cells
    Dunster LM, Gibson CA, Stephenson JR, Minor PD, Barrett AD
    J Gen Virol, 1990 Mar;71 ( Pt 3):601-7.
    PMID: 2155996
    The ability of passage in HeLa cells to attenuate flaviviruses was investigated for three different strains of the mosquito-borne West Nile (WN) virus and two tick-borne viruses, louping-ill and Langat. One strain of WN virus, Sarawak, was attenuated 4000-fold for adult mice by intraperitoneal or intranasal challenge after six HeLa passages. The HeLa-passaged virus was also found to be antigenically different and temperature-sensitive in its growth characteristics compared with the parent. After six HeLa cell passages the Egypt 101 and Smithburn strains of WN virus lost their ability to infect monkey kidney cells and no longer killed adult mice, although inoculated animals became sick for several days. In contrast, two tick-borne flaviviruses remained as virulent for mice after six HeLa passages as the parent non-HeLa-passaged virus. Neither of the tick-borne viruses exhibited characteristics associated with temperature sensitivity. The results, therefore, indicate that the mosquito-borne, but not tick-borne, flaviviruses can be attenuated by very few passages in HeLa cells. This observation may provide a model system with which to analyse the molecular basis of attenuation and/or virulence of mosquito-borne flaviviruses.
    Matched MeSH terms: Antigens, Viral/analysis
  6. Fulltext Gravid oviposition sticky trap and dengue non-structural 1 antigen test for early surveillance of dengue in multi-storey dwellings: study protocol of a cluster randomized controlled trial
    Liew JWK, Selvarajoo S, Tan W, Ahmad Zaki R, Vythilingam I
    Infect Dis Poverty, 2019 Sep 03;8(1):71.
    PMID: 31477185 DOI: 10.1186/s40249-019-0584-y
    BACKGROUND: Dengue is a global disease, transmitted by the Aedes vectors. In 2018, there were 80 615 dengue cases with 147 deaths in Malaysia. Currently, the nationwide surveillance programs are dependent on Aedes larval surveys and notifications of lab-confirmed human infections. The existing, reactive programs appear to lack sensitivity and proactivity. More efficient dengue vector surveillance/control methods are needed.

    METHODS: A parallel, cluster, randomized controlled, interventional trial is being conducted for 18 months in Damansara Damai, Selangor, Malaysia, to determine the efficacy of using gravid oviposition sticky (GOS) trap and dengue non-structural 1 (NS1) antigen test for early surveillance of dengue among Aedes mosquitoes to reduce dengue outbreaks. Eight residential apartments were randomly assigned into intervention and control arms. GOS traps are set at the apartments to collect Aedes weekly, following which dengue NS1 antigen is detected in these mosquitoes. When a dengue-positive mosquito is detected, the community will be advised to execute vector search-and-destroy and protective measures. The primary outcome concerns the the percentage change in the (i) number of dengue cases and (ii) durations of dengue outbreaks. Whereas other outcome measures include the change in density threshold of Aedes and changes in dengue-related knowledge, attitude and practice among cluster inhabitants.

    DISCUSSION: This is a proactive and early dengue surveillance in the mosquito vector that does not rely on notification of dengue cases. Surveillance using the GOS traps should be able to efficiently provide sufficient coverage for multistorey dwellings where population per unit area is likely to be higher. Furthermore, trapping dengue-infected mosquitoes using the GOS trap, helps to halt the dengue transmission carried by the mosquito. It is envisaged that the results of this randomized controlled trial will provide a new proactive, cheap and targeted surveillance tool for the prevention and control of dengue outbreaks.

    TRIAL REGISTRATION: This is a parallel-cluster, randomized controlled, interventional trial, registered at ClinicalTrials.gov (ID: NCT03799237), on 8th January 2019 (retrospectively registered).

    Matched MeSH terms: Antigens, Viral/analysis*
  7. Localization of dengue virus in naturally infected human tissues, by immunohistochemistry and in situ hybridization
    Jessie K, Fong MY, Devi S, Lam SK, Wong KT
    J Infect Dis, 2004 Apr 15;189(8):1411-8.
    PMID: 15073678
    Dengue viral antigens have been demonstrated in several types of naturally infected human tissues, but little is known of whether these same tissues have detectable viral RNA. We studied tissue specimens from patients with serologically or virologically confirmed dengue infections by immunohistochemistry (IHC) and in situ hybridization (ISH), to localize viral antigen and RNA, respectively. IHC was performed on specimens obtained from 5 autopsies and 24 biopsies and on 20 blood-clot samples. For ISH, antisense riboprobes to the dengue E gene were applied to tissue specimens in which IHC was positive. Viral antigens were demonstrated in Kupffer and sinusoidal endothelial cells of the liver; macrophages, multinucleated cells, and reactive lymphoid cells in the spleen; macrophages and vascular endothelium in the lung; kidney tubules; and monocytes and lymphocytes in blood-clot samples. Positive-strand viral RNA was detected in the same IHC-positive cells found in the spleen and blood-clot samples. The strong, positive ISH signal in these cells indicated a high copy number of viral RNA, suggesting replication.
    Matched MeSH terms: Antigens, Viral/analysis*
  8. Infectivity titration of the fast-replicating and cytopathic hepatitis A virus strain HM175A.2 by an in situ enzyme immunoassay
    Yap KL, Lam SK
    J Virol Methods, 1994 Apr;47(1-2):217-26.
    PMID: 8051228
    A simple, rapid and objective infectivity assay based on an in situ enzyme immunoassay (EIA) was developed for the fast-growing and cytopathic cell culture-adapted hepatitis A virus (HAV) strain HM175A.2. Infectivity titration by EIA correlated well with titration by cytopathic effects. The reliability of this assay was demonstrated by close agreement in virus infectivity titers among different assays of the same virus aliquot and between assays of different virus aliquots. HAV infected cell cultures after fixation could be stored for up to 1 week before testing without decline in virus titer.
    Matched MeSH terms: Antigens, Viral/analysis
  9. Enterovirus 71 encephalomyelitis and Japanese encephalitis can be distinguished by topographic distribution of inflammation and specific intraneuronal detection of viral antigen and RNA
    Wong KT, Ng KY, Ong KC, Ng WF, Shankar SK, Mahadevan A, et al.
    Neuropathol. Appl. Neurobiol., 2012 Aug;38(5):443-53.
    PMID: 22236252 DOI: 10.1111/j.1365-2990.2011.01247.x
    To investigate if two important epidemic viral encephalitis in children, Enterovirus 71 (EV71) encephalomyelitis and Japanese encephalitis (JE) whose clinical and pathological features may be nonspecific and overlapping, could be distinguished.
    Matched MeSH terms: Antigens, Viral/analysis*
  10. Comparison of two monoclonal antibody kits with cell culture isolation in the detection of respiratory virus antigens
    Khairullah NS
    Malays J Pathol, 1996 Jun;18(1):27-30.
    PMID: 10879221
    Two different preparations of monoclonal antibodies developed against respiratory viruses have been evaluated by the immunofluorescence antibody technique. The Chemicon monoclonal antibodies were found to be more efficient at picking up positive specimens with a high sensitivity and specificity than Imagen monoclonal antibodies. However, the overall concordance rate of the monoclonal antibodies was 92.3%-100%. Generally, when compared with cell culture isolation, the immunofluorescence antibody technique was found to be more sensitive. The high quality of the Chemicon monoclonal antibodies contribute to their value in providing definitive diagnosis, within a few hours of specimen collection, thus allowing early management of patients, their contacts and control of hospital infection.
    Matched MeSH terms: Antigens, Viral/analysis*
  11. HHV-6 antigen and viral DNA detected in cervical cells from archived tissue using histochemical staining and hybridization
    Yadav M, Arivananthan M, Kumar S
    Clin Diagn Virol, 1996 Oct;7(1):23-33.
    PMID: 9077427
    BACKGROUND: Human herpesvirus type 6 (HHV-6), an ubiquitous virus, is the causative agent for exanthem subitum. The virus is frequently associated with lymphoproliferative disorders and other diseases. Recently, we have reported the frequent presence of HHV-6 in oral carcinoma and the present study extends the observation to cervical carcinoma.

    OBJECTIVE: To examine the presence of HHV-6 in cervical carcinoma.

    STUDY DESIGN: Formalin-fixed, paraffin-embedded cervical carcinoma tissues were examined for the presence of HHV-6 by immunohistochemistry using two monoclonal antibodies that react to HHV-6-encoded p41/38 and gp116/64/54. In situ hybridization with variant-specific probes were used to type the HHV-6 DNA sequences present.

    RESULTS: A total of 14/26 (53.9%) carcinoma tissue specimens and 5/8 (62.5%) normal tissue specimens were positive for viral antigens. In situ hybridization studies revealed the presence of HHV-6 DNA sequences in 10/26 (38.5%) carcinoma tissue specimens and 1/8 (12.5%) normal tissue specimens. In the normal tissue, the HHV-6 was present in the endocervical ciliated columnar-epithelial cells and some cells in the subepithelial mucosa but in the carcinoma, the transformed cells were positive for the virus.

    CONCLUSIONS: HHV-6 viral proteins and DNA were found in more than one third of the cervical tissue examined suggesting possible viral expression in these tumours. The significance of the distribution and role of the HHV-6 in cervical tissue remains unclear. Since HHV-6 has an oncogenic potential, the virus may cooperate with other transforming agents for the progression of the disease.

    Matched MeSH terms: Antigens, Viral/analysis*
  12. Studies into the immunopathogenesis and laboratory diagnosis of dengue haemorrhagic fever
    Pang T
    Ann Acad Med Singap, 1987 Oct;16(4):612-6.
    PMID: 2895602
    Studies were carried out into the immunopathogenesis and laboratory diagnosis of dengue virus infections. Using an experimental system it was shown that cell-mediated immunity (CMI), as measured by delayed-type hypersensitivity (DTH) was induced in mice infected with dengue virus. The nature of the DTH response satisfies most criteria for a classical DTH reaction. In addition, it was also shown that infection with dengue virus causes a transient immunosuppression as measured by the immune response to other, unrelated antigens. With regard to the laboratory diagnosis of dengue infections, it was found that mosquito cells were a sensitive system for the isolation of dengue viruses and that the success of isolation was related to the antibody content of the serum. A new method for the rapid isolation of dengue viruses was also developed involving the intracerebral inoculation of mosquito larvae. By the use of this method viral antigens can be detected as early as 2-3 days after specimen inoculation. The significance of these findings in relation to the immunopathogenesis, prevention and control of disease syndromes due to dengue viruses is discussed.
    Matched MeSH terms: Antigens, Viral/analysis
  13. Expression of Epstein-Barr virus-encoded proteins in nasopharyngeal carcinoma
    Fåhraeus R, Fu HL, Ernberg I, Finke J, Rowe M, Klein G, et al.
    Int J Cancer, 1988 Sep 15;42(3):329-38.
    PMID: 2843473
    Expression of the Epstein-Barr virus (EBV) encoded nuclear antigens (EBNA 1 to 6) and membrane-associated protein (LMP) was investigated by immunoblotting in 83 nasopharyngeal carcinoma (NPC) biopsies and 25 other tumor and normal tissue specimens from the head and neck region. Fifty-eight of the 83 NPC biopsies were large enough to yield parallel data on virus DNA and viral expression. All 16 cases of clinically diagnosed and histologically confirmed NPCs from North Africa contained EBV DNA and expressed EBNA-1. Of 31 clinically diagnosed NPCs from China, 29 contained EBV DNA and 25 of these expressed EBNA-1. One control tissue biopsy from the oropharynx of NPC patients contained EBV DNA, but none expressed EBNA-1. The latent membrane protein (LMP) was detected in 22/31 of the Chinese and in 10/16 of the North African NPC biopsies. None of the NPC biopsies or control tissues expressed detectable amounts of EBNA 2 or any of the other 4 nuclear antigens which are invariably expressed in EBV-transformed B cells. A smaller number of tumors from Malaysia and East Africa exhibited a similar pattern of expression. EBV was rescued from a nude-mouse-passaged North African NPC tumor by co-cultivation of the tumor cells with umbilical cord blood lymphocytes. The tumor expressed EBNA 1 and LMP, but not EBNA 2 or the other 4 EBNAs. The resulting LCLs expressed all 6 nuclear antigens, EBNA 1 to 6 and LMP. Our data suggest that expression of the EBV genome is regulated in a tissue-specific fashion.
    Matched MeSH terms: Antigens, Viral/analysis*
  14. Intercontinental circulation of human influenza A(H1N2) reassortant viruses during the 2001-2002 influenza season
    Xu X, Smith CB, Mungall BA, Lindstrom SE, Hall HE, Subbarao K, et al.
    J Infect Dis, 2002 Nov 15;186(10):1490-3.
    PMID: 12404167
    Reassortant influenza A viruses bearing the H1 subtype of hemagglutinin (HA) and the N2 subtype of neuraminidase (NA) were isolated from humans in the United States, Canada, Singapore, Malaysia, India, Oman, Egypt, and several countries in Europe during the 2001-2002 influenza season. The HAs of these H1N2 viruses were similar to that of the A/New Caledonia/20/99(H1N1) vaccine strain both antigenically and genetically, and the NAs were antigenically and genetically related to those of recent human H3N2 reference strains, such as A/Moscow/10/99(H3N2). All 6 internal genes of the H1N2 reassortants examined originated from an H3N2 virus. This article documents the first widespread circulation of H1N2 reassortants on 4 continents. The current influenza vaccine is expected to provide good protection against H1N2 viruses, because it contains the A/New Caledonia/20/99(H1N1) and A/Moscow/10/99(H3N2)-like viruses, which have H1 and N2 antigens that are similar to those of recent H1N2 viruses.
    Matched MeSH terms: Antigens, Viral/analysis
  15. Fulltext Pathologic characterization of a murine model of human enterovirus 71 encephalomyelitis
    Ong KC, Badmanathan M, Devi S, Leong KL, Cardosa MJ, Wong KT
    J. Neuropathol. Exp. Neurol., 2008 Jun;67(6):532-42.
    PMID: 18520772 DOI: 10.1097/NEN.0b013e31817713e7
    We describe a model of Enterovirus 71 encephalomyelitis in 2-week-old mice that shares many features with the human central nervous system (CNS) disease. Mice were infected via oral and parenteral routes with a murine-adapted virus strain originally from a fatal human case. The mice succumbed to infection after 2 to 5 days. Vacuolated and normal-appearing CNS neurons showed viral RNA and antigens and virions by in situ hybridization, immunohistochemistry, and electron microscopy; inflammation was minimal. The most numerous infected neurons were in anterior horns, motor trigeminal nuclei, and brainstem reticular formation; fewer neurons in the red nucleus, lateral cerebellar nucleus, other cranial nerve nuclei, motor cortex, hypothalamus, and thalamus were infected. Other CNS regions, dorsal root, and autonomic ganglia were spared. Intramuscular-inoculated mice killed 24 to 36 hours postinfection had viral RNA and antigens in ipsilateral lumbar anterior horn cells and adjacent axons. Upper cord motor neurons, brainstem, and contralateral motor cortex neurons were infected from 48-72 hours. Viral RNA and antigens were abundant in skeletal muscle and adjacent tissues but not in other organs. The distinct, stereotypic viral distribution in this model suggests that the virus enters the CNS via peripheral motor nerves after skeletal muscle infection, and spread within the CNS involves motor and other neural pathways. This model may be useful for further studies on pathogenesis and for testing therapies.
    Matched MeSH terms: Antigens, Viral/analysis
  16. Experimental cross-infection of sheep and goats with different isolates of contagious ecthyma virus
    Zamri-Saad M, Roshidah I, al-Ajeeli K
    Aust. Vet. J., 1994 Jul;71(7):218-20.
    PMID: 7945102
    Matched MeSH terms: Antigens, Viral/analysis
  17. Arbovirus infections in Sarawak, October 1968--February 1970: Japanese encephalitis virus isolations from mosquitoes
    Simpson DI, Bowen ET, Way HJ, Platt GS, Hill MN, Kamath S, et al.
    Ann Trop Med Parasitol, 1974 Dec;68(4):393-404.
    PMID: 4155608
    Matched MeSH terms: Antigens, Viral/analysis
  18. Fulltext First round of external quality assessment of dengue diagnostics in the WHO Western Pacific Region, 2013
    Pok KY, Squires RC, Tan LK, Takasaki T, Abubakar S, Hasebe F, et al.
    Western Pac Surveill Response J, 2015 Jun 30;6(2):73-81.
    PMID: 26306220 DOI: 10.5365/WPSAR.2015.6.1.017
    Accurate laboratory testing is a critical component of dengue surveillance and control. The objective of this programme was to assess dengue diagnostic proficiency among national-level public health laboratories in the World Health Organization (WHO) Western Pacific Region.
    Matched MeSH terms: Antigens, Viral/analysis
  19. Human Hendra virus infection causes acute and relapsing encephalitis
    Wong KT, Robertson T, Ong BB, Chong JW, Yaiw KC, Wang LF, et al.
    Neuropathol. Appl. Neurobiol., 2009 Jun;35(3):296-305.
    PMID: 19473296 DOI: 10.1111/j.1365-2990.2008.00991.x
    To study the pathology of two cases of human Hendra virus infection, one with no clinical encephalitis and one with relapsing encephalitis.
    Matched MeSH terms: Antigens, Viral/analysis
  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.
    Matched MeSH terms: Antigens, Viral/analysis
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