Displaying publications 141 - 160 of 175 in total

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  1. Yadav M, Arivananthan M, Chandrashekran A, Tan BS, Hashim BY
    J Oral Pathol Med, 1997 Oct;26(9):393-401.
    PMID: 9385576
    Archival oral tissues comprising 51 squamous cell carcinomas, 18 non-malignant lesions and 7 normal mucosa samples were investigated for human herpesvirus-6 (HHV-6)-encoded antigens and HHV-6 DNA. The virus-specific antigens were detected by an immunohistochemical method using monoclonal antibodies. Two further techniques used for HHV-6 DNA detection included the polymerase chain reaction (PCR) with virus-specific primers and in situ hybridization using digoxigenin-labelled oligonucleotides specific for HHV-6A and HHV-6B genotypes. A high proportion (79-80%) of the squamous cell carcinomas were positive for HHV-6 with the various detection methods. In cases of lichen planus and leukoplakia a high prevalence rate (67-100%) was noted with in situ hybridization and immunohistochemical techniques but a lower proportion (22-33%) was detected with the PCR method. All 7 normal tissues tested were negative for HHV-6. The HHV-6 variant B was found in 60% of the oral carcinoma tissues analysed. The study demonstrates the frequent presence of HHV-6 in neoplastic and non-malignant lesions of the oral cavity. While the role of HHV-6 in oral mucosal tissues remains to be determined, the in vitro tumorigenic potential of the virus suggests a possible role in the etiopathogenesis of oral lesions.
    Matched MeSH terms: DNA, Viral/analysis*
  2. Yadav M, Nambiar S, Khoo SP, Yaacob HB
    Arch Oral Biol, 1997 Aug;42(8):559-67.
    PMID: 9347118
    The prevalence and cellular distribution of human herpesvirus 7 (HHV-7) in archival labial salivary glands was analysed for virus-specific DNA sequences by polymerase chain reaction (PCR) and in situ hybridization signals. In addition, the cellular expression of HHV-7-encoded protein was detected by immunohistochemical staining with a virus-specific monoclonal antibody. Eleven of 20 samples were positive for the HHV-7 DNA sequence by PCR. Eighteen of 20 tissues analysed by in situ hybridization showed signals in ductal, serous and mucous cells. Some nuclei of these cells and also the myoepithelial population were positive. In immunolocalization studies, all 20 salivary glands consistently showed HHV-7-expressed protein in the cytoplasm of ductal cuboidal and columnar cells. The protein was also found in the cytoplasm of mucous and serous acinar cells that were immunopositive for HHV-7. The observations are consistent with the suggestion that the labial salivary gland is a site for virus replication, potential persistence and a source of infective HHV-7 in saliva.
    Matched MeSH terms: DNA, Viral/analysis
  3. Kim LH, Peh SC, Poppema S
    Int J Cancer, 2003 Nov 1;107(2):250-5.
    PMID: 12949802
    Isolation of single cells permits analysis of DNA or RNA from individual cells among heterogeneous populations. This technique is particularly useful in the study of classical Hodgkin's lymphoma (cHL) due to the scarcity of H/RS tumor cells among large numbers of reactive leukocytes. In a previous study, we found a high frequency of dual LMP-1 variant (concurrent presence of deleted and nondeleted variants) in cHL from whole-tissue sections. For the present study, we applied a single-cell isolation technique to determine the LMP-1 oncogene variant in EBV-associated H/RS cells. Five cases of EBV-infected cHL, containing nondeleted (n=1), deleted (n=1) and dual infection (n=3) based on whole-tissue section analysis, were selected for study. Paraffin-embedded tissue sections were stained with antibody to LMP-1 and positively stained H/RS cells isolated using a semiautomated micromanipulator. Each isolated single cell was subjected to PCR for amplification of the LMP-1 gene flanking the 30 bp deletion region and Xho1 restriction site. Cases with either nondeleted variant or the deleted variant showed similar LMP-1 variant expression in isolated single H/RS cells. However, 1 of the 3 cases with dual variants showed only the deleted variant in H/RS cells. The other 2 cases showed mixed patterns of deleted, nondeleted and dual LMP-1 variants in isolated single H/RS cells. All cases showed loss of the Xho1 restriction site, with the exception of the case with nondeleted LMP-1. Results of single-H/RS cell analysis of the Xho1 restriction site concur with those of whole-tissue section amplification. A mixed pattern of LMP-1 variants was observed in isolated H/RS cells, and it is speculated that this is due to the accumulation of mutation and deletion events.
    Matched MeSH terms: DNA, Viral/analysis
  4. Liu W, Wang YT, Tian DS, Yin ZC, Kwang J
    Dis Aquat Organ, 2002 Apr 24;49(1):11-8.
    PMID: 12093036
    The vp28 gene encoding an envelope protein (28 kDa) of white spot syndrome virus (WSSV) was amplified from WSSV-infected tiger shrimp that originated from Malaysia. Recombinant VP28 protein (r-28) was expressed in Escherichia coli and used as an antigen for preparation of monoclonal antibodies (MAbs). Three murine MAbs (6F6, 6H4 and 9C10) that were screened by r-28 antigen-based enzyme-linked immunosorbent assay (ELISA) were also able to recognize viral VP28 protein as well as r-28 on Western blot. Three non-overlapping epitopes of VP28 protein were determined using the MAbs in competitive ELISA; thus, an antigen-capture ELISA (Ac-ELISA) was developed by virtue of these MAbs. Ac-ELISA can differentiate WSSV-infected shrimp from uninfected shrimp and was further confirmed by a polymerase chain reaction (PCR) and Western blot. Approximately 400 pg of purified WSSV sample and 20 pg of r-28 could be detected by Ac-ELISA, which is comparable in sensitivity to PCR assay but more sensitive than Western blot in the detection of purified virus. Hemolymph and tissue homogenate samples collected from a shrimp farm in Malaysia during December 2000 and July 2001 were also detected by Ac-ELISA and PCR with corroborating results.
    Matched MeSH terms: DNA, Viral/analysis
  5. Fadilah N, Hanafiah A, Razlan H, Wong ZQ, Mohamed Rose I, Rahman MM
    Br J Biomed Sci, 2016 Oct;73(4):180-187.
    PMID: 27922429
    BACKGROUND: No gold standard has yet been established for the diagnosis of H. pylori infection. A multiplex polymerase chain reaction (mPCR) was developed in this study for rapid, sensitive and specific detection of H. pylori from gastric biopsies.

    METHODS: H. pylori infections were determined by in-house rapid urease test (iRUT), culture, histology and multiplex PCR.

    RESULTS: A total of 140 (60.9%) from 230 patients were positive for H. pylori infection. H. pylori were detected in 9.6% (22/230), 17% (39/230), 12.6% (29/230) and 60% (138/230) of biopsy specimens by culture, iRUT, histology and mPCR, respectively. mPCR identified H. pylori infection in 100% of biopsies with positive histology and culture. All biopsies with positive iRUT yielded positive PCR except two cases. mPCR also detected H. pylori in additional 116, 101 and 109 biopsies that were negative by culture, iRUT and histology, respectively. Positive samples by mPCR showed lower average in H. pylori density, activity and inflammation scores. The Indians showed the highest prevalence of H. pylori infection compared to the Chinese and the Malays. In addition, Chinese patients with older age were significantly infected compared to other ethnicities.

    CONCLUSION: PCR was able to detect the highest numbers of positive cases although the lowest average scores were recorded in the activity, inflammatory and H. pylori density.

    Matched MeSH terms: DNA, Viral/analysis*
  6. Candotti D, Lin CK, Belkhiri D, Sakuldamrongpanich T, Biswas S, Lin S, et al.
    Gut, 2012 Dec;61(12):1744-53.
    PMID: 22267593 DOI: 10.1136/gutjnl-2011-301281
    To investigate the molecular basis of occult hepatitis B virus (HBV) infection (OBI) in Asian blood donors.
    Matched MeSH terms: DNA, Viral/analysis
  7. Farhadi A, Behzad-Behbahani A, Geramizadeh B, Sekawi Z, Rahsaz M, Sharifzadeh S
    J Med Virol, 2014 Jul;86(7):1134-44.
    PMID: 24700118 DOI: 10.1002/jmv.23945
    Limited data exist regarding whether a high-risk human papillomavirus (HR-HPV) infection increases the risk of developing renal cell carcinoma. The aim of this study was to investigate whether HPV infection has a role in the pathogenesis or development of a certain histological subtype of renal cell carcinoma. Formalin-fixed paraffin-embedded (FFPE) specimens of 122 patients with histopathologically proven renal cell carcinoma and their respective peritumoral tissues were examined. The presence of HPV-DNA was determined by a combination of MY/GP+ consensus primers and HPV-16/18 type specific nested PCRs followed by direct sequencing. Catalyzed signal-amplified colorimetric in situ hybridization (CSAC-ISH) technique was applied to determine the physical status of viral genome. The expression of p16INK4a and HPV L1 capsid proteins was evaluated using immunohistochemistry. HPV genome was detected in 37 (30.3%) tumor specimens and their four (4.1%) corresponding peritumoral tissues. HPV-18 was the most common viral type identified followed by HPV-16 and 58. Immunoexpression of p16INK4a was detected in 24 (20.3%) cases. Data analysis showed a significant correlation between p16INK4a expression and the presence of HR-HPV DNA (P DNA. Diffuse signal pattern was identified in 15 (83.3%) samples whereas a mixed pattern of diffuse and punctate signals was only detectable in three cases. The results indicate an association of HR-HPV types with renal cell carcinoma. It is proposed that HPV infection in high-grade tumors might precede disease progression in a number of tumors, particularly of the papillary subtype.
    Matched MeSH terms: DNA, Viral/genetics
  8. Shanmugam H, Eow GI, Nadarajan VS
    Malays J Pathol, 2009 Jun;31(1):63-6.
    PMID: 19694316 MyJurnal
    Adult T-cell leukaemia/lymphoma (ATLL) is a rare T lymphoproliferative disorder which is aetiologically linked with human T-cell lymphotropic virus type-1 (HTLV-1). HTLV-1 is endemic in Japan, Caribbean and Africa. The highest incidence of ATLL is in Japan although sporadic cases have been reported elsewhere in the world. We describe a case of ATLL with an unusual presentation which we believe is the first reported case of ATLL in Malaysia based on our literature search. A 51-year-old Indian lady was referred to University Malaya Medical Centre for an incidental finding of lymphocytosis while being investigated for pallor and giddiness. Clinical examination revealed bilateral shotty cervical lymph nodes with no hepato-splenomegaly or skin lesions. Laboratory investigations showed absolute lymphocytosis (38 x 10(9)/L) with a mildly increased serum lactate dehydrogenase. The peripheral blood smear showed the presence of predominantly small to medium sized, non-flower lymphocytes. The bone marrow showed similar findings of prominent lymphocytosis. Immunophenotyping of the bone marrow mononuclear cells showed CD3+, CD4+, CD5+, CD7- and CD25+ which is characteristic of ATLL phenotype. HTLV-1 infection was confirmed by the presence of HTLV-1 proviral DNA in the tumor cells using conventional Polymerase Chain Reaction (PCR) and real-time PCR. Here, we discuss the pathogenesis and characteristics of ATLL as well as the detection of HTLV-1 by real time PCR.
    Matched MeSH terms: DNA, Viral/analysis
  9. Saini R, Tang TH, Zain RB, Cheong SC, Musa KI, Saini D, et al.
    J Cancer Res Clin Oncol, 2011 Feb;137(2):311-20.
    PMID: 20419384 DOI: 10.1007/s00432-010-0886-8
    PURPOSE: The purpose of this study was to evaluate the role of HPV and p53 polymorphisms in oral squamous cell carcinomas (OSCC) affecting Malaysian population.

    METHODS: We analysed frozen samples from 105 OSCC as well as 105 oral specimens derived from healthy individuals. PCR assays targeting two regions of the virus were used. PCR amplification for the analysis of p53 codon 72 arginine/proline alleles was carried out in a separate reaction.

    RESULTS: HPV DNA was detected in 51.4% OSCC samples, while 24.8% controls were found to be HPV positive. HPV was found to be significantly associated with OSCC (P 

    Matched MeSH terms: DNA, Viral/isolation & purification
  10. Tan EL, Selvaratnam G, Kananathan R, Sam CK
    BMC Cancer, 2006;6:227.
    PMID: 16995954
    Nasopharyngeal carcinoma (NPC) is a common epithelial neoplasm among the Chinese populations in Southern China and South East Asia. Epstein-Barr virus (EBV) is known to be an important etiologic agent of NPC and the viral gene products are frequently detected in NPC tissues along with elevated antibody titres to the viral proteins (VCA and EA) in a majority of patients. Elevated plasma EBV DNA load is regarded as an important marker for the presence of the disease and for the monitoring of disease progression. However, other serum/plasma parameters such as the levels of certain interleukins and growth factors have also been implicated in NPC. The objectives of the present study are, 1) to investigate the correlations between plasma EBV DNA load and the levels of interleukin (IL)-6, IL-10, TGF-beta1 and SCF (steel factor) and 2) to relate these parameters to the stages of NPC and the effect of treatment.
    Matched MeSH terms: DNA, Viral/blood
  11. Yap YY, Hassan S, Chan M, Choo PK, Ravichandran M
    Otolaryngol Head Neck Surg, 2007 Jun;136(6):986-91.
    PMID: 17547993
    OBJECTIVES: This study examines the presence of Epstein-Barr virus (EBV) in nasopharyngeal carcinoma (NPC) by using polymerase chain reaction (PCR).

    STUDY DESIGN: Eighty-six postnasal biopsy samples and 71 fine-needle aspirate samples of neck masses were obtained from patients who were clinically suspect for NPC. Genomic DNA was extracted from the samples, and EBNA1, EBNA2, and LMP genes of EBV were detected by PCR. PCR results were compared with NPC histopathology findings.

    RESULTS: The sensitivity of PCR to detect EBNA1 (97.14%), EBNA2 (88.57%), and LMP (91.43%) genes of EBV in nasopharyngeal biopsy samples were higher than those in fine-needle aspirate samples.

    CONCLUSION: Detection of EBV by PCR in tissue obtained from nasopharyngeal biopsy and fine-needle aspirate samples of neck masses is a relatively inexpensive, reliable, and accurate method of diagnosing NPC. Detection of EBV genes is on par with histopathological examination (HPE) and superior to fine-needle aspirate cytology.

    SIGNIFICANCE: PCR is an ideal tool for suggesting NPC and guiding the diagnostic workup in occult primary tumors, facilitating earlier diagnosis and reducing morbidity and mortality.

    Matched MeSH terms: DNA, Viral/analysis*
  12. Chong PP, Asyikin N, Rusinahayati M, Halimatun S, Rozita R, Ng CK, et al.
    Asian Pac J Cancer Prev, 2010;11(6):1645-51.
    PMID: 21338211
    Persistent high-risk human papillomavirus (HPV) infection is known to play an important role in the genesis of cervical cancer. Since new screening and prevention strategies, namely improved HPV testing and HPV vaccination have been aggressively promoted recently, it is crucial to investigate the HPV distribution in Malaysia in order to maximize their cost-effectiveness. This study was therefore conducted to assess the HPV type distribution in the most populous region, the state of Selangor. A total of 200 cervical swab samples were collected in two health-screening campaigns, and also from women attending obstetrics and gynecology clinics in several hospitals in Selangor. DNA extraction was performed and HPV DNA was detected via nested PCR using MY09/MY11 as outer primers and GP5+/GP6+ as inner primers which target the L1 gene of the viral genome. The purified PCR products were subjected to automated DNA sequencing to determine the HPV genotype. Out of 180 β-globin positive samples, 84 (46.7%) were positive for HPV DNA. The most common HPV type found was high-risk oncogenic type 16 (40%), followed by HPV type 18 (3.3%), HPV 33 (1.7%), HPV 31 (0.6%), and low-risk HPV 87 (0.6%). Our study confirmed that nested PCR method is highly sensitive in detecting HPV DNA even in low risk patients. Since a relatively high prevalence rate of HPV infection was found in this population, prompt healthcare policy changes to bring about implementation of early HPV vaccination program is desirable to prevent a high incidence of cervical cancer.

    Study site: Gynaecology and Obstetrics Clinics in Selangor (Hospital Kajang, Hospital Serdang, and the Britannia Women and Children Specialist Centre)
    Matched MeSH terms: DNA, Viral/genetics*
  13. Loke CF, Omar AR, Raha AR, Yusoff K
    Vet Immunol Immunopathol, 2005 Jul 15;106(3-4):259-67.
    PMID: 15963824
    Specific-pathogen free (SPF) chickens were inoculated with the plasmid constructs encoding the fusion (F) and haemagglutinin-neuraminidase (HN) glycoproteins of Newcastle disease virus (NDV), either individually or in combination and challenged with velogenic NDV. The antibody level against NDV was measured using commercial enzyme linked immunosorbent assay (ELISA). In the first immunization regimen, SPF chickens inoculated twice with NDV-F or NDV-HN constructs elicited antibody responses 1 week after the second injection. However, the levels of the antibody were low and did not confer significant protection from the lethal challenge. In addition, administration of the plasmid constructs with Freund's adjuvant did not improve the level of protection. In the second immunization regimen, chickens inoculated twice with the plasmid constructs emulsified with Freund's adjuvant induced significant antibody titers after the third injection. Three out of nine (33.3%) chickens vaccinated with pEGFP-HN, five of ten (50.0%) chickens vaccinated with pEGFP-F and nine of ten (90.0%) chickens vaccinated with combined pEGFP-F and pEGFP-HN were protected from the challenge. No significant differences in the levels of protection were observed when the chickens were vaccinated with linearized pEGFP-F. The results suggested that more than two injections with both F and HN encoding plasmid DNA were required to induce higher level of antibodies for protection against velogenic NDV in chickens.
    Matched MeSH terms: DNA, Viral/genetics
  14. 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: DNA, Viral/blood
  15. Latiff LA, Rahman SA, Wee WY, Dashti S, Andi Asri AA, Unit NH, et al.
    Asian Pac J Cancer Prev, 2015;16(2):559-64.
    PMID: 25684487
    BACKGROUND: The participation of women in cervical cancer screening in Malaysia is low. Self-sampling might be able to overcome this problem.The aim of this study was to assess the reliability of self-sampling for cervical smear in our country.

    MATERIALS AND METHODS: This cross-sectional study was conducted on 258 community dwelling women from urban and rural settings who participated in health campaigns. In order to reduce the sampling bias, half of the study population performed the self-sampling prior to the physician sampling while the other half performed the self-sampling after the physician sampling, randomly. Acquired samples were assessed for cytological changes as well as HPV DNA detection.

    RESULTS: The mean age of the subjects was 40.4±11.3 years. The prevalence of abnormal cervical changes was 2.7%. High risk and low risk HPV genotypes were found in 4.0% and 2.7% of the subjects, respectively. A substantial agreement was observed between self-sampling and the physician obtained sampling in cytological diagnosis (k=0.62, 95%CI=0.50, 0.74), micro-organism detection (k=0.77, 95%CI=0.66, 0.88) and detection of hormonal status (k=0.75, 95%CI=0.65, 0.85) as well as detection of high risk (k=0.77, 95%CI=0.4, 0.98) and low risk (K=0.77, 95%CI=0.50, 0.92) HPV. Menopausal state was found to be related with 8.39 times more adequate cell specimens for cytology but 0.13 times less adequate cell specimens for virological assessment.

    CONCLUSIONS: This study revealed that self-sampling has a good agreement with physician sampling in detecting HPV genotypes. Self-sampling can serve as a tool in HPV screening while it may be useful in detecting cytological abnormalities in Malaysia.

    Matched MeSH terms: DNA, Viral/genetics
  16. Hamzi Abdul Raub S, Isa NM, Zailani HA, Omar B, Abdullah MF, Mohd Amin WA, et al.
    Asian Pac J Cancer Prev, 2014;15(2):651-6.
    PMID: 24568473
    BACKGROUND: Cervical cancer is the third commonest type of cancer among women in Malaysia. Our aim was to determine the distribution of human papilloma virus (HPV) genotypes in cervical cancer in our multi-ethnic population.

    MATERIALS AND METHODS: This was a multicentre study with a total of 280 cases of cervical cancer from 4 referral centres in Malaysia, studied using real-time polymerase chain reaction (qPCR) detection of 12 high risk-HPV genotypes.

    RESULTS: Overall HPV was detected in 92.5% of cases, in 95.9% of squamous cell carcinomas and 84.3%of adenocarcinomas. The five most prevalent high-risk HPV genotypes were HPV 16 (68.2%), 18 (40%), 58 (10.7%), 33 (10.4%) and 52 (10.4%). Multiple HPV infections were more prevalent (55.7%) than single HPV infections (36.8%). The percentage of HPV positive cases in Chinese, Malays and Indians were 95.5%, 91.9% and 80.0%, respectively. HPV 16 and 18 genotypes were the commonest in all ethnic groups. We found that the percentage of HPV 16 infection was significantly higher in Chinese (75.9%) compared to Malays (63.7%) and Indians (52.0%) (p<0.05), while HPV 18 was significantly higher in Malays (52.6%) compared to Chinese (25.0%) and Indians (28%) (p<0.05). Meanwhile, HPV 33 (17.9%) and 52 (15.2%) were also more commonly detected in the Chinese (p<0.05).

    CONCLUSIONS: This study showed that the distribution of HPV genotype in Malaysia is similar to other Asian countries. Importantly, we found that different ethnic groups in Malaysia have different HPV genotype infection rates, which is a point to consider during the implementation of HPV vaccination.

    Matched MeSH terms: DNA, Viral/genetics
  17. Latiff LA, Ibrahim Z, Pei CP, Rahman SA, Akhtari-Zavare M
    Asian Pac J Cancer Prev, 2015;16(18):8495-501.
    PMID: 26745108
    PURPOSE: This study was conducted to assess the agreement and differences between cervical self-sampling with a Kato device (KSSD) and gynecologist sampling for Pap cytology and human papillomavirus DNA (HPV DNA) detection.

    MATERIALS AND METHODS: Women underwent self-sampling followed by gynecologist sampling during screening at two primary health clinics. Pap cytology of cervical specimens was evaluated for specimen adequacy, presence of endocervical cells or transformation zone cells and cytological interpretation for cells abnormalities. Cervical specimens were also extracted and tested for HPV DNA detection. Positive HPV smears underwent gene sequencing and HPV genotyping by referring to the online NCBI gene bank. Results were compared between samplings by Kappa agreement and McNemar test.

    RESULTS: For Pap specimen adequacy, KSSD showed 100% agreement with gynecologist sampling but had only 32.3% agreement for presence of endocervical cells. Both sampling showed 100% agreement with only 1 case detected HSIL favouring CIN2 for cytology result. HPV DNA detection showed 86.2%agreement (K=0.64, 95% CI 0.524-0.756, p=0.001) between samplings. KSSD and gynaecologist sampling identified high risk HPV in 17.3% and 23.9% respectively (p= 0.014).

    CONCLUSION: The self-sampling using Kato device can serve as a tool in Pap cytology and HPV DNA detection in low resource settings in Malaysia. Self-sampling devices such as KSSD can be used as an alternative technique to gynaecologist sampling for cervical cancer screening among rural populations in Malaysia.

    Matched MeSH terms: DNA, Viral/genetics
  18. Yong YK, Saeidi A, Tan HY, Rosmawati M, Enström PF, Batran RA, et al.
    Front Immunol, 2018;9:472.
    PMID: 29616020 DOI: 10.3389/fimmu.2018.00472
    Mucosal-associated invariant T (MAIT) cells, defined as CD161++TCR iVα7.2+ T cells, play an important role in the innate defense against bacterial infections, and their functionality is impaired in chronic viral infections. Here, we investigated the frequency and functional role of MAIT cells in chronic hepatitis B virus (HBV) infection. The peripheral CD3+CD161++TCR iVα7.2+ MAIT cells in chronic HBV-infected patients and healthy controls were phenotypically characterized based on CD57, PD-1, TIM-3, and CTLA-4, as well as HLA-DR and CD38 expression. The frequency of MAIT cells was significantly decreased among chronic HBV-infected individuals as compared to controls. Expression of CD57, PD-1, CTLA-4, as well as HLA-DR and CD38 on MAIT cells was significantly elevated in chronic HBV-infected individuals relative to controls. The percentage of T cell receptor (TCR) iVα7.2+ CD161+ MAIT cells did not correlate with HBV viral load but inversely with HLA-DR on CD4+ T cells and MAIT cells and with CD57 on CD8+ T cells suggesting that decrease of MAIT cells may not be attributed to direct infection by HBV but driven by HBV-induced chronic immune activation. The percentage and expression levels of PD-1 as well as CTLA-4 on MAIT cells inversely correlated with plasma HBV-DNA levels, which may suggest either a role for MAIT cells in the control of HBV infection or the effect of HBV replication in the liver on MAIT cell phenotype. We report that decrease of TCR iVα7.2+ MAIT cells in the peripheral blood and their functions were seemingly impaired in chronic HBV-infected patients likely because of the increased expression of PD-1.
    Matched MeSH terms: DNA, Viral
  19. Tsai WS, Shih SL, Green SK, Jan FJ
    Plant Dis, 2007 Jul;91(7):907.
    PMID: 30780410 DOI: 10.1094/PDIS-91-7-0907A
    Whitefly-transmitted, cucurbit-infecting begomoviruses (genus Begomovirus, family Geminiviridae) have been detected on cucurbit crops in Bangladesh, China, Egypt, Israel, Malaysia, Mexico, the Philippines, Thailand, United States, and Vietnam. Pumpkin plants showing leaf curling, blistering, and yellowing symptoms were observed in the AVRDC fields (Tainan, Taiwan) during 2001 and in nearby farmers' fields during 2005. Two samples from symptomatic plants were collected in 2001 and six collected in 2005. Viral DNAs were extracted (2), and the PCR, with previously described primers, was used to detect the presence of begomoviral DNA-A (4), DNA-B (3), and associated satellite DNA (1). Begomoviral DNA-A was detected in one of the 2001 samples and in all 2005 samples. The PCR-amplified 1.5 kb viral DNA-A from one positive sample each from the 2001 and 2005 collections was cloned and sequenced. On the basis of the 1.5-kb DNA-A sequences, specific primers were designed to completely sequence the DNA-A component. The overlap between fragments obtained using primer walking ranged from 43 to 119 bp with 100% nt identities. The complete DNA-A sequences were determined for the two isolates as 2,734 bp (2001) (GenBank Accession No. DQ866135) and 2,733 bp (2005) (GenBank Accession No. EF199774). Sequence comparisons and analyses were performed using the DNAMAN Sequence Analysis Software (Lynnon Corporation, Vaudreuil, Quebec, Canada). The DNA-A of the begomovirus isolates each contained the conserved nanosequence-TAATATTAC and six open reading frames, including two in the virus sense and four in the complementary sense. On the basis of a 99% shared nucleotide sequence identity, they are considered isolates of the same species. BLASTn analysis and a comparison of the sequence with others available in the GenBank database ( http://www.ncbi.nlm.nih.gov ) indicated that the Taiwan virus shared its highest nt identity (more than 95%) with the Squash leaf curl Philippines virus (GenBank Accession No. AB085793). Virus-associated satellite DNA was not found in any of the samples. DNA-B was found in both samples, providing further evidence that the virus was the same as the bipartite Squash leaf curl Philippines virus. To our knowledge, this is the first report of Squash leaf curl Philippines virus in Taiwan. References: (1) R. W. Briddon et al. Virology 312:106, 2003. (2) R. L. Gilbertson et al. J. Gen. Virol. 72:2843, 1991. (3) S. K. Green et al. Plant Dis. 85:1286, 2001. (4) M. R. Rojas et al. Plant Dis. 77:340, 1993.
    Matched MeSH terms: DNA, Viral
  20. Vilcek S, Stadejek T, Ballagi-Pordány A, Lowings JP, Paton DJ, Belák S
    Virus Res, 1996 Aug;43(2):137-47.
    PMID: 8864203
    The genetic variability of classical swine fever virus was studied by comparative nucleotide sequence analysis of 76 virus isolates, collected during a half century from three continents. Parts of the E2 (gp55) and the polymerase gene coding regions of the viral genome were amplified by RT-PCR and DNA fragments of 254 and 207 bp, respectively, were sequenced. The comparative sequence analysis of the E2 region revealed two main phylogenetic groups of CSFV, indicating that the virus apparently evolved from two ancestor nodes. Group I (represented by Brescia strain) consisted of old and recent American and Asian viruses, as well as old English isolates from the 1950s. This group was subdivided into three subgroups, termed I.A-I.C. Group II (represented by Alfort strain) consisted of relatively recent isolates from Europe, together with strain Osaka, which was isolated in Japan from a pig of European origin. Based on genetic distances the group was divided into subgroups II.A and II.B. Malaysian isolates were branched into both groups, indicating multiple origins for contemporaneous outbreaks in that country. All ten vaccine strains tested were branched in group I, implying a common ancestor. The Japanese Kanagawa strain, isolated in 1974, and the British Congenital Tremor strain from 1964 were the most distinct variants of CSFV in our collection. The comparison of the nucleotide sequences of the polymerase coding region of 32 European strains distinguished subgroups II.A and II.B which were similar to the corresponding subgroups of the E2 phylogenetic tree. Thus, the results revealed that the E2 region and the polymerase coding regions seem to be appropriate for the grouping of CSFV isolates from all over the world, distinguishing two major groups of the virus. The reliability of these regions for phylogenetic analysis is indicated by the similarity of the results obtained from the two separate parts of the CSFV genome.
    Matched MeSH terms: DNA, Viral
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