Displaying publications 881 - 900 of 1059 in total

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  1. Hepatitis markers in Malaysians with hepatocellular carcinoma
    Lopez JB, Thambyrajah V, Balasegaram M, Satgunasingam N
    Br J Biomed Sci, 1994 Jun;51(2):177-80.
    PMID: 7519505
    Sera from 80 Malaysians with confirmed hepatocellular carcinoma were tested for five markers of the hepatitis B virus, anti-HCV and anti-HDV by enzyme immunoassay, and alpha fetoprotein (AFP) was measured by radioimmunoassay. Of the patients, 98.8% had evidence of HBV infection and 75% were positive for HBsAg--which latter correlated with AFP raised above cut-off values of 500 ng/ml (P = 0.0001) and 200 ng/ml (P = 0.005). Males correlated significantly with the presence of HBsAg (P = 0.002). Thirty-one per cent of HBsAg positive patients were also positive for HBeAg and 74% for anti-HBe. Twenty per cent of the cases were concurrently positive for both HBsAg and anti-HBs. Six of 70 (8.6%) patients were positive for anti-HCV, of whom four were also positive for HBsAg. None of 67 patients tested for anti-HDV were positive. The results strongly indicate an important aetiological role for hepatitis B virus in causation of hepatocellular carcinoma among Malaysians.
    Matched MeSH terms: Hepatitis B Antigens/blood*
  2. In vivo comparison of local versus systemic delivery of immunostimulating siRNA in HPV-driven tumours
    Khairuddin N, Blake SJ, Firdaus F, Steptoe RJ, Behlke MA, Hertzog PJ, et al.
    Immunol Cell Biol, 2014 Feb;92(2):156-63.
    PMID: 24217808 DOI: 10.1038/icb.2013.75
    Small interfering RNAs (siRNAs) to inhibit oncogene expression and also to activate innate immune responses via Toll-like receptor (TLR) recognition have been shown to be beneficial as anti-cancer therapy in certain cancer models. In this study, we investigated the effects of local versus systemic delivery of such immune-stimulating Dicer-substrate siRNAs (IS-DsiRNAs) on a human papillomavirus (HPV)-driven tumour model. Localized siRNA delivery using intratumour injection of siRNA was able to increase siRNA delivery to the tumour compared with intravenous (IV) delivery and potently activated innate immune responses. However, IV injection remained the more effective delivery route for reducing tumour growth. Although IS-DsiRNAs activated innate immune cells and required interferon-α (IFNα) for full effect on tumour growth, we found that potent silencing siRNA acting independently of IFNα were overall more effective at inhibiting TC-1 tumour growth. Other published work utilising IS-siRNAs have been carried out on tumour models with low levels of major histocompatibility complex (MHC)-class 1, a target of natural killer cells that are potently activated by IS-siRNA. As TC-1 cells used in our study express high levels of MHC-class I, the addition of the immunostimulatory motifs may not be as beneficial in this particular tumour model. Our data suggest that selection of siRNA profile and delivery method based on tumour environment is crucial to developing siRNA-based therapies.
    Matched MeSH terms: Histocompatibility Antigens Class I/immunology
  3. Fulltext Nasopharyngeal carcinoma in Brunei Darussalam: low incidence among the Chinese and an evaluation of antibodies to Epstein-Barr virus antigens as biomarkers
    Yeo CH, Hsien YC, Abdullah MS, Telesinghe PU, Ramasamy R
    Singapore Med J, 2009 Apr;50(4):371-7.
    PMID: 19421680
    Little or no information is available on the prevalence of nasopharyngeal carcinoma (NPC) among different ethnic groups in Brunei, or how useful plasma IgA antibodies are against viral capsid antigen (VCA) and early antigen (EA) in the diagnosis of NPC, even though they are routinely measured in patients suspected to have NPC.
    Matched MeSH terms: Antigens, Viral/immunology*
  4. Fulltext The immunophenotypic patterns of follicle centre and mantle zone in Castleman's disease
    Peh SC, Shaminie J, Poppema S, Kim LH
    Singapore Med J, 2003 Apr;44(4):185-91.
    PMID: 12952030
    Castleman's disease is an uncommon disease and the histopathogenesis is poorly understood. This study aims to investigate their clinicopathological and immunophenotypic profile.
    Matched MeSH terms: Antigens, CD/metabolism
  5. Fulltext Primary oesophageal Ki (CD30)-positive ALK+ anaplastic large cell lymphoma of T-cell phenotype
    Yaakup H, Sagap I, Fadilah SA
    Singapore Med J, 2008 Oct;49(10):e289-92.
    PMID: 18946602
    Primary oesophageal lymphoma is a very rare entity, with fewer than 30 reported cases worldwide. It represents an important cause of dysphagia. Most of the oesophageal lymphomas are diffuse large B-cell type, with only one reported case of anaplastic large cell lymphoma (ALCL) of T-cell phenotype. Primary oesophageal lymphomas that are not associated with an immunocompromised state tend to affect elderly patients. We describe the first case of primary oesophageal Ki (CD30)-positive ALK+ALCL of T-cell phenotype in a 34-year-old immunocompetent woman, who presented with a two-year history of dysphagia. She was treated with chemotherapy and endoscopic oesophageal dilations and stenting, resulting in complete remission of the lymphoma and resolution of the dysphagia. She then underwent autologous peripheral blood haematopoietic stem cell transplantation and remained disease-free two years after the diagnosis.
    Matched MeSH terms: Antigens, CD30/biosynthesis*
  6. Fulltext Hb E beta +-thalassaemia in west Malaysia: clinical features in the most common beta-thalassaemia mutation of the Malays [IVS 1-5 (G-->C)]
    George E, Wong HB
    Singapore Med J, 1993 Dec;34(6):500-3.
    PMID: 8153710
    Patients with the Hb beta + [IVS 1-5 (G-->C)] clinically presented as beta-thalassaemia intermedia and remained asymptomatic in the absence of blood transfusions. With or without blood transfusions the patients were short and had moderate to marked thalassaemia facies. Children who received blood transfusions showed progressive iron loading with age. The serum ferritin and serum alanine transaminase levels were significantly raised in the patients who were given blood transfusions. In the presence of blood transfusions, and absence of adequate iron chelation therapy, splenectomy became an inevitable event at some stage of the disease because of increasing transfusing requirements.
    Matched MeSH terms: Hepatitis B Surface Antigens/blood
  7. Fulltext Hepatitis C--the Malaysian story
    Sinniah M, Ooi BG
    Singapore Med J, 1993 Apr;34(2):132-4.
    PMID: 8266152
    We studied the presence of Hepatitis C Virus (HCV) antibodies in a defined Malaysian population and examined the association, if any, between HCV and the Hepatitis B Virus (HBV), using sensitive recombinant DNA second generation Enzyme Immunoassay (EIA) test kits. This sero-prevalence study comprised 1,434 sera from eleven distinct groups comprising intravenous drug users (IVDU), haemophiliacs, male homosexuals, female prostitutes, healthy blood donors, staff of dialysis unit and laboratory personnel, chronic renal failure patients undergoing dialysis (CRFD), patients with liver cirrhosis, chronic active hepatitis, chronic persistent hepatitis and primary liver cancer. Except in laboratory personnel and dialysis staff, HCV antibodies were detected in each group of patients ranging from 3% in blood donors to 85% in IVDU. The main modes of HCV transmission identified were parenteral drug use, transfusion and/or dialysis related. The HBV was found to be the major viral etiological agent in 75% of chronic liver disease (CLD); while in 10% of cases both HCV and HBV were detected. HCV was implicated as the sole viral agent in only a small proportion (1.5%) of patients with chronic liver disease.
    Matched MeSH terms: Hepatitis B Surface Antigens/analysis
  8. Fulltext Development of a Phage Display Panning Strategy Utilizing Crude Antigens: Isolation of MERS-CoV Nucleoprotein human antibodies
    Lim CC, Woo PCY, Lim TS
    Sci Rep, 2019 Apr 15;9(1):6088.
    PMID: 30988390 DOI: 10.1038/s41598-019-42628-6
    Antibody phage display has been pivotal in the quest to generate human monoclonal antibodies for biomedical and research applications. Target antigen preparation is a main bottleneck associated with the panning process. This includes production complexity, downstream purification, quality and yield. In many instances, purified antigens are preferred for panning but this may not be possible for certain difficult target antigens. Here, we describe an improved procedure of affinity selection against crude or non-purified antigen by saturation of non-binders with blocking agents to promote positive binder enrichment termed as Yin-Yang panning. A naïve human scFv library with kappa light chain repertoire with a library size of 109 was developed. The improved Yin-Yang biopanning process was able to enrich monoclonal antibodies specific to the MERS-CoV nucleoprotein. Three unique monoclonal antibodies were isolated in the process. The Yin-Yang biopanning method highlights the possibility of utilizing crude antigens for the isolation of monoclonal antibodies by phage display.
    Matched MeSH terms: Antigens, Viral/immunology*
  9. Fulltext The combinatorial diversity of KIR and HLA class I allotypes in Peninsular Malaysia
    Tao S, Kichula KM, Harrison GF, Farias TDJ, Palmer WH, Leaton LA, et al.
    Immunology, 2021 Apr;162(4):389-404.
    PMID: 33283280 DOI: 10.1111/imm.13289
    Killer cell immunoglobulin-like receptors (KIRs) interact with polymorphic human leucocyte antigen (HLA) class I molecules, modulating natural killer (NK) cell functions and affecting both the susceptibility and outcome of immune-mediated diseases. The KIR locus is highly diverse in gene content, copy number and allelic polymorphism within individuals and across geographical populations. To analyse currently under-represented Asian and Pacific populations, we investigated the combinatorial diversity of KIR and HLA class I in 92 unrelated Malay and 75 Malaysian Chinese individuals from the Malay Peninsula. We identified substantial allelic and structural diversity of the KIR locus in both populations and characterized novel variations at each analysis level. The Malay population is more diverse than Malay Chinese, likely representing a unique history including admixture with immigrating populations spanning several thousand years. Characterizing the Malay population are KIR haplotypes with large structural variants present in 10% individuals, and KIR and HLA alleles previously identified in Austronesian populations. Despite the differences in ancestries, the proportion of HLA allotypes that serve as KIR ligands is similar in each population. The exception is a significantly reduced frequency of interactions of KIR2DL1 with C2+ HLA-C in the Malaysian Chinese group, caused by the low frequency of C2+ HLA. One likely implication is a greater protection from preeclampsia, a pregnancy disorder associated with KIR2DL1, which shows higher incidence in the Malay than in the Malaysian Chinese. This first complete, high-resolution, characterization of combinatorial diversity of KIR and HLA in Malaysians will form a valuable reference for future clinical and population studies.
    Matched MeSH terms: HLA-C Antigens/genetics*
  10. Phenotyping of lymphocytes expressing regulatory and effector markers in infiltrating ductal carcinoma of the breast
    Leong PP, Mohammad R, Ibrahim N, Ithnin H, Abdullah M, Davis WC, et al.
    Immunol Lett, 2006 Feb 15;102(2):229-36.
    PMID: 16246429
    Dysfunction of the host immune system in cancer patients can be due to a number of reasons including suppression of tumour associated antigen reactive lymphocytes by regulatory T (Treg) cells. In this study, we used flow cytometry to determine the phenotype and relative abundance of the tumour infiltrating lymphocytes (TILs) from 47 enzymatically dissociated tumour specimens from patients with infiltrating ductal carcinoma (IDC) of the breast. The expression of both effector and regulatory markers on the TILs were determined by using a panel of monoclonal antibodies. Analysis revealed CD8(+) T cells (23.4+/-2.1%) were predominant in TILs, followed by CD4(+) T cells (12.6+/-1.7%) and CD56(+) natural killer cells (6.4+/-0.7%). The CD4(+)/CD8(+) ratio was 0.8+/-0.9%. Of the CD8(+) cells, there was a higher number (68.4+/-3.5%) that expressed the effector phenotype, namely, CD8(+)CD28(+) and about 46% of this subset expressed the activation marker, CD25. Thus, a lower number of infiltrating CD8(+) T cells (31.6+/-2.8%) expressed the marker for the suppressor phenotype, CD8(+)CD28(-). Of the CD4(+) T cells, 59.6+/-3.9% expressed the marker for the regulatory phenotype, CD4(+)CD25(+). About 43.6+/-3.8% CD4(+)CD25(+) subset co-expressed both the CD152 and FOXP3, the Treg-associated molecules. A positive correlation was found between the presence of CD4(+)CD25(+) subset and age (> or =50 years old) (r=0.51; p=0.045). However, no significant correlation between tumour stage and CD4(+)CD25(+) T cells was found. In addition, we also found that the CD4(+)CD25(-) subset correlated with the expression of the nuclear oestrogen receptor (ER)-alpha in the tumour cells (r=0.45; p=0.040). In conclusion, we detected the presence of cells expressing the markers for Tregs (CD4(+)CD25(+)) and suppressor (CD8(+)CD28(-)) in the tumour microenvironment. This is the first report of the relative abundance of Treg co-expressing CD152 and FOXP3 in breast carcinoma.
    Matched MeSH terms: Antigens, CD28/analysis
  11. Anti-idiotype vaccine against cancer
    Bhattacharya-Chatterjee M, Chatterjee SK, Foon KA
    Immunol Lett, 2000 Sep 15;74(1):51-8.
    PMID: 10996628
    Immunization with anti-idiotype (Id) antibodies represents a novel new approach to active immunotherapy. Extensive studies in animal tumor models have demonstrated the efficacy of anti-Id vaccines in preventing tumor growth and curing mice with established tumor. We have developed and characterized several murine monoclonal anti-Id antibodies (Ab2) which mimic distinct human tumor-associated antigens (TAA) and can be used as surrogate antigens for triggering active anti-tumor immunity in cancer patients. Encouraging results have been obtained in recent clinical trials. In this article, we will review the existing literature and summarize our own findings showing the potential of this approach for various human cancers. We will also discuss where anti-Id vaccines may perform better than traditional antigen vaccines.
    Matched MeSH terms: Antigens, Neoplasm/immunology
  12. Differential positive selection of malaria resistance genes in three indigenous populations of Peninsular Malaysia
    Liu X, Yunus Y, Lu D, Aghakhanian F, Saw WY, Deng L, et al.
    Hum Genet, 2015 Apr;134(4):375-92.
    PMID: 25634076 DOI: 10.1007/s00439-014-1525-2
    The indigenous populations from Peninsular Malaysia, locally known as Orang Asli, continue to adopt an agro-subsistence nomadic lifestyle, residing primarily within natural jungle habitats. Leading a hunter-gatherer lifestyle in a tropical jungle environment, the Orang Asli are routinely exposed to malaria. Here we surveyed the genetic architecture of individuals from four Orang Asli tribes with high-density genotyping across more than 2.5 million polymorphisms. These tribes reside in different geographical locations in Peninsular Malaysia and belong to three main ethno-linguistic groups, where there is minimal interaction between the tribes. We first dissect the genetic diversity and admixture between the tribes and with neighboring urban populations. Later, by implementing five metrics, we investigated the genome-wide signatures for positive natural selection of these Orang Asli, respectively. Finally, we searched for evidence of genomic adaptation to the pressure of malaria infection. We observed that different evolutionary responses might have emerged in the different Orang Asli communities to mitigate malaria infection.
    Matched MeSH terms: Antigens, CD95/genetics
  13. Fulltext Isolated hepatitis B core antibody positive among vaccinated cohort in Malaysia
    Hudu SA, Malik YA, Niazlin MT, Harmal NS, Alshrari AS, Sekawi Z
    Ann Saudi Med, 2013;33(6):591-4.
    PMID: 24413864 DOI: 10.5144/0256-4947.2013.591
    BACKGROUND AND OBJECTIVES: Hepatitis B core antibodies (anti-HBc) are detected in almost every patient with previous exposure to hepatitis B virus (HBV). However, with this marker alone, one cannot understand the activity of the disease; therefore, this study aimed to identify the implication of isolated hepatitis B core antibody and evaluate the effect of hepatitis B vaccine booster in isolated anti-HBc among adults who received the HBV vaccine as infants.

    DESIGN AND SETTINGS: A prospective cohort study of vaccinated undergraduate students of University Putra Malaysia.

    PATIENTS AND METHODS: A total of 408 undergraduate students who received infant hepatitis B vaccination volunteered for this study; 5 mL of venous blood was taken from the volunteers. Hepatitis B surface antigen (HBsAg) and core antibodies were tested using a commercially available enzyme-linked immunosorbent assay kit according to the manufacturer's instructions (DRG international Inc., USA). Molecular detection of hepatitis B viral DNA was performed using nested polymerase chain reaction.

    RESULTS: The prevalence of isolated anti-HBc among the vaccinated cohort was found to be 5.0%, out of which 80% had a hepatitis B surface antibodies (anti-HBs) titer higher than 10 IU/L, while 20% had less than 10 IU/L anti-HBs titer. All the anti-HBc positivesubjects had detectable hepatitis B viral DNA in their serum. Anamnestic response was found to be 100% among isolated anti-HBc with negative antibody.

    CONCLUSION: Isolated anti-HBc developed protective levels of anti-HBs after a single dose of recombinant hepatitis B vaccination. HBV DNA was detected in all isolated anti-HBc indicating occult chronic HBV infection with undetectable HBsAg.

    Matched MeSH terms: Hepatitis B Surface Antigens/immunology*
  14. 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
  15. Fulltext Association of Pre-diagnostic Antibody Responses to Escherichia coli and Bacteroides fragilis Toxin Proteins with Colorectal Cancer in a European Cohort
    Butt J, Jenab M, Werner J, Fedirko V, Weiderpass E, Dahm CC, et al.
    Gut Microbes, 2021;13(1):1-14.
    PMID: 33874856 DOI: 10.1080/19490976.2021.1903825
    Experimental evidence has implicated genotoxic Escherichia coli (E. coli) and enterotoxigenic Bacteroides fragilis (ETBF) in the development of colorectal cancer (CRC). However, evidence from epidemiological studies is sparse. We therefore assessed the association of serological markers of E. coli and ETBF exposure with odds of developing CRC in the European Prospective Investigation into Nutrition and Cancer (EPIC) study.Serum samples of incident CRC cases and matched controls (n = 442 pairs) were analyzed for immunoglobulin (Ig) A and G antibody responses to seven E. coli proteins and two isoforms of the ETBF toxin via multiplex serology. Multivariable-adjusted conditional logistic regression analyses were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association of sero-positivity to E. coli and ETBF with CRC.The IgA-positivity of any of the tested E. coli antigens was associated with higher odds of developing CRC (OR: 1.42; 95% CI: 1.05-1.91). Dual-positivity for both IgA and IgG to E. coli and ETBF was associated with >1.7-fold higher odds of developing CRC, with a significant association only for IgG (OR: 1.75; 95% CI: 1.04, 2.94). This association was more pronounced when restricted to the proximal colon cancers (OR: 2.62; 95% CI: 1.09, 6.29) compared to those of the distal colon (OR: 1.24; 95% CI: 0.51, 3.00) (pheterogeneity = 0.095). Sero-positivity to E. coli and ETBF was associated with CRC development, suggesting that co-infection of these bacterial species may contribute to colorectal carcinogenesis. These findings warrant further exploration in larger prospective studies and within different population groups.
    Matched MeSH terms: Antigens, Bacterial/immunology
  16. Fulltext Anti-tumour promoting activity and antioxidant properties of girinimbine isolated from the stem bark of Murraya koenigii S
    Kok YY, Mooi LY, Ahmad K, Sukari MA, Mat N, Rahmani M, et al.
    Molecules, 2012 Apr 20;17(4):4651-60.
    PMID: 22522395 DOI: 10.3390/molecules17044651
    Girinimbine, a carbazole alkaloid isolated from the stem bark of Murraya koenigii was tested for the in vitro anti-tumour promoting and antioxidant activities. Anti-tumour promoting activity was determined by assaying the capability of this compound to inhibit the expression of early antigen of Epstein-Barr virus (EA-EBV) in Raji cells that was induced by the tumour promoter, phorbol 12-myristate 13-acetate. The concentration of this compound that gave an inhibition rate at fifty percent was 6.0 µg/mL and was not cytotoxic to the cells. Immunoblotting analysis of the expression of EA-EBV showed that girinimbine was able to suppress restricted early antigen (EA-R). However, diffused early antigen (EA-D) was partially suppressed when used at 32.0 µg/mL. Girinimbine exhibited a very strong antioxidant activity as compared to a-tocopherol and was able to inhibit superoxide generation in the 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced differentiated premyelocytic HL-60 cells more than 95%, when treated with the compound at 5.3 and 26.3 µg/mL, respectively. However girinimbine failed to scavenge the stable diphenyl picryl hydrazyl (DPPH)-free radical.
    Matched MeSH terms: Antigens, Viral/genetics
  17. Fulltext Travel-related Streptococcal toxic shock syndrome caused by emm type 78 Streptococcus pyogenes
    Tappe D, Schulze MH, van der Linden M, Ziegler U, Müller A, Stich A
    J Clin Microbiol, 2011 Aug;49(8):3094-5.
    PMID: 21632896 DOI: 10.1128/JCM.02623-10
    Streptococcal toxic shock syndrome is a serious health problem in developed and developing countries. We here report a case of severe protracted disease after a minor skin infection in a young traveler returning from West Malaysia which was caused by an unusual emm-type strain harboring speG and smeZ superantigen genes.
    Matched MeSH terms: Antigens, Bacterial/genetics
  18. Fulltext Combining parasite lactate dehydrogenase-based and histidine-rich protein 2-based rapid tests to improve specificity for diagnosis of malaria Due to Plasmodium knowlesi and other Plasmodium species in Sabah, Malaysia
    Grigg MJ, William T, Barber BE, Parameswaran U, Bird E, Piera K, et al.
    J Clin Microbiol, 2014 Jun;52(6):2053-60.
    PMID: 24696029 DOI: 10.1128/JCM.00181-14
    Plasmodium knowlesi causes severe and fatal malaria in Malaysia. Microscopic misdiagnosis is common and may delay appropriate treatment. P. knowlesi can cross-react with "species-specific" parasite lactate dehydrogenase (pLDH) monoclonal antibodies used in rapid diagnostic tests (RDTs) to detect P. falciparum and P. vivax. At one tertiary-care hospital and two district hospitals in Sabah, we prospectively evaluated two combination RDTs for malaria diagnosis by using both a pan-Plasmodium-pLDH (pan-pLDH)/P. falciparum-specific-pLDH (Pf-pLDH) RDT (OptiMAL-IT) and a non-P. falciparum VOM-pLDH/Pf-HRP2 RDT (CareStart). Differential cross-reactivity among these combinations was hypothesized to differentiate P. knowlesi from other Plasmodium monoinfections. Among 323 patients with PCR-confirmed P. knowlesi (n = 193), P. falciparum (n = 93), and P. vivax (n = 37) monoinfections, the VOM-pLDH individual component had the highest sensitivity for nonsevere (35%; 95% confidence interval [CI], 27 to 43%) and severe (92%; CI, 81 to 100%) P. knowlesi malaria. CareStart demonstrated a P. knowlesi sensitivity of 42% (CI, 34 to 49%) and specificity of 74% (CI, 65 to 82%), a P. vivax sensitivity of 83% (CI, 66 to 93%) and specificity of 71% (CI, 65 to 76%), and a P. falciparum sensitivity of 97% (CI, 90 to 99%) and specificity of 99% (CI, 97 to 100%). OptiMAL-IT demonstrated a P. knowlesi sensitivity of 32% (CI, 25 to 39%) and specificity of 21% (CI, 15 to 29%), a P. vivax sensitivity of 60% (CI, 42 to 75%) and specificity of 97% (CI, 94 to 99%), and a P. falciparum sensitivity of 82% (CI, 72 to 89%) and specificity of 39% (CI, 33 to 46%). The combination of CareStart plus OptiMAL-IT for P. knowlesi using predefined criteria gave a sensitivity of 25% (CI, 19 to 32%) and specificity of 97% (CI, 92 to 99%). Combining two RDT combinations was highly specific for P. knowlesi malaria diagnosis; however, sensitivity was poor. The specificity of pLDH RDTs was decreased for P. vivax and P. falciparum because of P. knowlesi cross-reactivity and cautions against their use alone in areas where P. knowlesi malaria is endemic. Sensitive P. knowlesi-specific RDTs and/or alternative molecular diagnostic tools are needed in areas where P. knowlesi malaria is endemic.
    Matched MeSH terms: Antigens, Protozoan/analysis*
  19. Fulltext Evaluation of the sensitivity of a pLDH-based and an aldolase-based rapid diagnostic test for diagnosis of uncomplicated and severe malaria caused by PCR-confirmed Plasmodium knowlesi, Plasmodium falciparum, and Plasmodium vivax
    Barber BE, William T, Grigg MJ, Piera K, Yeo TW, Anstey NM
    J Clin Microbiol, 2013 Apr;51(4):1118-23.
    PMID: 23345297 DOI: 10.1128/JCM.03285-12
    Plasmodium knowlesi can cause severe and fatal human malaria in Southeast Asia. Rapid diagnosis of all Plasmodium species is essential for initiation of effective treatment. Rapid diagnostic tests (RDTs) are sensitive for detection of uncomplicated and severe falciparum malaria but have not been systematically evaluated in knowlesi malaria. At a tertiary referral hospital in Sabah, Malaysia, we prospectively evaluated the sensitivity of two combination RDTs for the diagnosis of uncomplicated and severe malaria from all three potentially fatal Plasmodium species, using a pan-Plasmodium lactate dehydrogenase (pLDH)-P. falciparum histidine-rich protein 2 (PfHRP2) RDT (First Response) and a pan-Plasmodium aldolase-PfHRP2 RDT (ParaHIT). Among 293 hospitalized adults with PCR-confirmed Plasmodium monoinfection, the sensitivity of the pLDH component of the pLDH-PfHRP2 RDT was 74% (95/129; 95% confidence interval [CI], 65 to 80%), 91% (110/121; 95% CI, 84 to 95%), and 95% (41/43; 95% CI, 85 to 99%) for PCR-confirmed P. knowlesi, P. falciparum, and P. vivax infections, respectively, and 88% (30/34; 95% CI, 73 to 95%), 90% (38/42; 95% CI, 78 to 96%), and 100% (12/12; 95% CI, 76 to 100%) among patients tested before antimalarial treatment was begun. Sensitivity in severe malaria was 95% (36/38; 95% CI, 83 to 99), 100% (13/13; 95% CI, 77 to 100), and 100% (7/7; 95% CI, 65 to 100%), respectively. The aldolase component of the aldolase-PfHRP2 RDT performed poorly in all Plasmodium species. The pLDH-based RDT was highly sensitive for the diagnosis of severe malaria from all species; however, neither the pLDH- nor aldolase-based RDT demonstrated sufficiently high overall sensitivity for P. knowlesi. More sensitive RDTs are needed in regions of P. knowlesi endemicity.
    Matched MeSH terms: Antigens, Protozoan/genetics
  20. Fulltext Evaluation of a commercial SD dengue virus NS1 antigen capture enzyme-linked immunosorbent assay kit for early diagnosis of dengue virus infection
    Wang SM, Sekaran SD
    J Clin Microbiol, 2010 Aug;48(8):2793-7.
    PMID: 20573879 DOI: 10.1128/JCM.02142-09
    Early definitive diagnosis of dengue virus infection may help in the timely management of dengue virus infection. We evaluated the Standard Diagnostics (SD, South Korea) dengue virus nonstructural protein NS1 antigen enzyme-linked immunosorbent assay (SD dengue NS1 Ag ELISA) for the detection of dengue virus NS1 antigen in patients' sera, using a total of 399 serum samples in a comparison with real-time reverse transcription (RT)-PCR, an in-house IgM capture (MAC)-ELISA, and a hemagglutination inhibition (HI) assay. Of the 320 dengue sera, 205 (64%) tested positive for NS1 antigen compared to 300 (93.75%) by either MAC-ELISA or RT-PCR, 161 (50.31%) by RT-PCR, and 226 (70.36%) by MAC-ELISA only. The assay was able to detect NS1 antigen in convalescent-phase sera until day 14 of infection. The NS1 detection rate is inversely proportional while the IgM detection rate is directly proportional to the presence of IgG antibodies. The overall sensitivity and specificity of the SD dengue NS1 Ag ELISA in the detection of "confirmed dengue virus" sera are 76.76% and 98.31%, respectively. This suggests that the SD kit is highly specific and sensitive for the detection of NS1 antigen. However, caution is needed when the kit is used as a single assay, as detection in samples that contained the virus was only about 81.97%. Combining this assay with an IgM and/or IgG assay will increase the sensitivity of detection, especially in areas with a higher prevalence of secondary dengue virus infections.
    Matched MeSH terms: Antigens, Viral/blood*
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