Displaying publications 141 - 160 of 328 in total

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  1. Recombinant proteins in the diagnosis of toxoplasmosis
    Kotresha D, Noordin R
    APMIS, 2010 Aug;118(8):529-42.
    PMID: 20666734 DOI: 10.1111/j.1600-0463.2010.02629.x
    Toxoplasma gondii is an important human pathogen with a worldwide distribution. It is primarily of medical importance for pregnant women and immunocompromised patients. Primary infection of the former is often associated with fetal infection, which can lead to abortion or severe neonatal malformation. Immunocompromised patients are at risk of contracting the severe form of the disease that may be fatal. Thus, detection of T. gondii infection with high sensitivity and specificity is crucial in the management of the disease. Toxoplasmosis is generally diagnosed by demonstrating specific immunoglobulin M (IgM) and IgG antibodies to toxoplasma antigens in the patient's serum sample. Most of the commercially available tests use T. gondii native antigens and display wide variations in test accuracy. Recombinant antigens have great potential as diagnostic reagents for use in assays to detect toxoplasmosis. Thus in this review, we address recent advances in the use of Toxoplasma recombinant proteins for serodiagnosis of toxoplasmosis.
    Matched MeSH terms: Immunoglobulin G/blood
  2. Fulltext Impact of a measles elimination strategy on measles incidence in Malaysia
    Saraswathy TS, Zahrin HN, Norhashmimi H, Az-Ulhusna A, Zainah S, Rohani J
    Southeast Asian J. Trop. Med. Public Health, 2009 Jul;40(4):742-7.
    PMID: 19842408
    In Malaysia, the two dose measles - mumps - rubella (MMR) vaccine was introduced in the Expanded Program on Immunization in 2002. The Ministry of Health then initiated a measles elimination strategy which included enhanced case-based surveillance with laboratory testing of all suspected cases. The objective of our study was to analyse national measles laboratory data from 2004 to 2008 to study the impact of the nationwide strategy on measles case incidence. Blood samples collected from suspected measles cases during the acute stage of the illness were investigated for measles specific IgM. The estimated incidence of measles ranged from 22.3 cases (in 2004) to 2.27 cases (in 2006) per 100,000 population. During this time, the measles vaccination coverage was above 85%. Laboratory confirmed measles cases dropped from 42.2% in 2004, when sporadic outbreaks were reported, to 3.9% in 2007. Screening for measles IgG levels in 2008 showed that 82.8% of those > 7 years old had adequate immunity. The measles control strategy appears to have been successful in reducing the incidence of measles. Continuing high vaccination coverage rates and ongoing measles surveillance are necessary to achieve our goal of measles elimination.
    Matched MeSH terms: Immunoglobulin G/blood
  3. Epitope mapping of Burkholderia pseudomallei serine metalloprotease: identification of serine protease epitope mimics
    Chan SW, Nathan S
    FEMS Immunol. Med. Microbiol., 2005 Jan 1;43(1):37-44.
    PMID: 15607634
    Filamentous phage random peptide libraries were used to identify the epitopes of Burkholderia pseudomallei protease by panning against IgG polyclonal sera that exhibited protease neutralizing properties. The isolated fusion peptides presented a consensus peptide sequence, TKSMALSG, which closely resembles part of the active site sequence, 435GTSMATPHVAG445, of B. pseudomallei serine metalloprotease. By comparing the consensus sequence, TKSMALSG, with the predicted three-dimensional molecular model of B. pseudomallei serine metalloprotease, it appears that the potential antibody binding epitope was buried within the molecule. This active site was conformational whereby one continuous sub-region (SMA) was located between two discontinuous sub-regions, supplied by the flanking residues in the same polypeptide. All phages selected from the biopanning with IgG polyclonal sera showed good binding towards the polyclonal antibodies when compared to the negative control. In addition, these peptide-bearing phages showed competitive inhibition of B. pseudomallei serine metalloprotease binding to the polyclonal IgG.
    Matched MeSH terms: Immunoglobulin G/immunology
  4. Fulltext Emergence of chikungunya seropositivity in healthy Malaysian adults residing in outbreak-free locations: chikungunya seroprevalence results from the Malaysian Cohort
    Azami NA, Salleh SA, Shah SA, Neoh HM, Othman Z, Zakaria SZ, et al.
    BMC Infect Dis, 2013;13:67.
    PMID: 23379541 DOI: 10.1186/1471-2334-13-67
    In 1998, Malaysia experienced its first chikungunya virus (CHIKV) outbreak in the suburban areas followed by another two in 2006 (rural areas) and 2008 (urban areas), respectively. Nevertheless, there is still a lack of documented data regarding the magnitude of CHIKV exposure in the Malaysian population. The aim of this study was to determine the extent of chikungunya virus infection in healthy Malaysian adults residing in outbreak-free locations.
    Matched MeSH terms: Immunoglobulin G/blood
  5. Fulltext Laboratory detection of strongyloidiasis: IgG-, IgG4 - and IgE-ELISAs and cross-reactivity with lymphatic filariasis
    Norsyahida A, Riazi M, Sadjjadi SM, Muhammad Hafiznur Y, Low HC, Zeehaida M, et al.
    Parasite Immunol., 2013 May-Jun;35(5-6):174-9.
    PMID: 23448095 DOI: 10.1111/pim.12029
    Enzyme-linked immunosorbent assays (ELISAs) were developed for the detection of IgG, IgG4 and IgE antibodies against Strongyloides stercoralis. A commercial ELISA (IVD Research, USA) was also used, and the sensitivities and specificities of the four assays were determined. Serum samples from 26 patients with S. stercoralis infection and 55 patients with other infections or no infection were analysed. Sensitivities of the IgG4 , IgG, IgE and IgG (IVD) assays were 76.9%, 84.6%, 7.7% and 84.6%, respectively, while the specificities were 92.7%, 81.8%, 100% and 83.6%, respectively. If filariasis samples were excluded, the specificities of the IgG4 -ELISA and both IgG-ELISAs increased to 100% and 98%, respectively. A significant positive correlation was observed between IgG- and IgG4 -ELISAs (r = 0.4828; P = 0.0125). IgG- and IgG- (IVD) ELISAs (r = 0.309) were positively correlated, but was not significant (P = 0.124). Meanwhile there was no correlation between IgG4 - and IgG- (IVD) ELISAs (r = 0.0042; P = 0.8294). Sera from brugian filariasis patients showed weak, positive correlation between the titres of antifilarial IgG4 and the optical densities of anti-Strongyloides IgG4 -ELISA (r = 0.4544, P = 0.0294). In conclusion, the detection of both anti-Strongyloides IgG4 and IgG antibodies could improve the serodiagnosis of human strongyloidiasis. Furthermore, patients from lymphatic filariasis endemic areas who are serologically diagnosed with strongyloidiasis should also be tested for filariasis.
    Matched MeSH terms: Immunoglobulin G/blood
  6. Specificity and sensitivity of a rapid dipstick test (Brugia Rapid) in the detection of Brugia malayi infection
    Rahmah N, Taniawati S, Shenoy RK, Lim BH, Kumaraswami V, Anuar AK, et al.
    Trans R Soc Trop Med Hyg, 2002 1 31;95(6):601-4.
    PMID: 11816429
    A total of 753 serum samples from 6 institutions in 3 countries (Malaysia, Indonesia and India) were used to evaluate an immunochromatographic rapid dipstick test, Brugia Rapid, for diagnosis of Brugia malayi infection. The samples comprised sera from 207 microfilaria-positive individuals and 546 individuals from filaria non-endemic areas. The latter consisted of 70 individuals with soil-transmitted helminth infections, 68 with other helminth infections, 238 with protozoan infections, 12 with bacterial and viral infections and 158 healthy individuals. The dipstick is prepared with a goat anti-mouse antibody control line and a B. malayi recombinant-antigen test line. First, the dipstick is dipped into a well containing diluted patient serum, thus allowing specific anti-filarial antibody in the serum to react with the recombinant antigen. Then the dipstick is placed into an adjacent well containing reconstituted anti-human IgG4-gold. After 10 min, development of 2 red-purplish lines denotes a positive result and one line indicates a negative reaction. The overall results of the evaluation showed 97% sensitivity, 99% specificity, 97% positive predictive value and 99% negative predictive value. Brugia Rapid is thus a promising diagnostic tool for detection of B. malayi infection, and would be especially useful for the brugian filariasis elimination programme.
    Matched MeSH terms: Immunoglobulin G/analysis
  7. Antigenic types of Orientia tsutsugamushi in Malaysia
    Tay ST, Rohani MY, Ho TM, Devi S
    Southeast Asian J. Trop. Med. Public Health, 2002 Sep;33(3):557-64.
    PMID: 12693591
    The seroprevalence of various Orientia tsutsugamushi (OT) strains among Malaysian patients with suspected scrub typhus infections was determined using an indirect immunoperoxidase (IIP) assay. IgG against a single OT strain were detected in six sera (3 Karp, 1 Gilliam and 2 TC586), whereas IgM antibodies against a single OT strain (Gilliam) were noted in 3 sera (Gilliam). IgG reactive to all OT strains were present in 33 (47.1%) of the 70 sera and IgM reactive to all OT strains were present in 22 (78.6%) of the 28 sera. The fact that most sera were reactive to multiple OT strains suggests that group-specific antigens are involved in scrub typhus infections, whereas very few were due to strain-specific epitopes present on these strains. Peak IgG and IgM titers were noted more frequently against Gilliam, Karp, and TA763 strains: this suggests that these strains may be the commonest infecting strains among Malaysian patients. Two predominant OT polypeptides consistently reacted with patients' sera were the 70 kDa and 56 kDa proteins.
    Matched MeSH terms: Immunoglobulin G/blood
  8. Detection of immunoglobulins M and G using culture filtrate antigen of Burkholderia pseudomallei
    Chenthamarakshan V, Vadivelu J, Puthucheary SD
    Diagn Microbiol Infect Dis, 2001 Jan;39(1):1-7.
    PMID: 11173184
    IgM and IgG based ELISA systems were developed using the culture filtrate antigen (CFA) of Burkholderia pseudomallei. The assays were evaluated using 95 sera from 66 septicemic cases and 47 sera from 20 cases with localized melioidosis. In addition 65 sera from culture negative cases that were also serologically negative for other endemic infections clinically suspected of melioidosis were included. These were compared with sera from 260 non-melioidosis cases, 169 sera from individuals with high risk of acquiring the infection and 48 sera from healthy controls. The IgG-ELISA was 96% sensitive and 94% specific. All sera from cases with septicemic and localized infections and 61 of 63 sera from clinically suspected melioidosis cases were positive for IgG antibody. The geometric mean titre index (GMTI) values of IgG antibody in melioidosis cases were significantly higher (p < 0.0005) compared to that of healthy subjects, high risk group and subjects with non-melioidosis infections. The sensitivity and specificity of IgM ELISA was 74 and 99% respectively. The GMTI value of IgM antibody in the sera of melioidosis cases was significantly higher as compared to that of non-melioidosis disease controls (p < or = 0.001). These results demonstrate that the detection of IgG is a better indicator of the disease in the diagnosis of melioidosis.
    Matched MeSH terms: Immunoglobulin G/blood*
  9. Rapid and reliable serological diagnosis of enteric fever: comparative sensitivity and specificity of Typhidot and Typhidot-M tests in febrile Malaysian children
    Choo KE, Davis TM, Ismail A, Tuan Ibrahim TA, Ghazali WN
    Acta Trop, 1999 Mar 15;72(2):175-83.
    PMID: 10206117
    The Typhidot test, which detects IgM and IgG antibodies to a Salmonella typhi-specific outer membrane protein, is as sensitive as, and more specific than, the Widal test in the diagnosis of enteric fever in Malaysian children. It is easier and quicker to perform. In order to increase diagnostic accuracy in an area of high endemicity, the Typhidot-M test has been developed in which IgG is first removed. This theoretically allows improved detection of IgM, and thus would differentiate new from recent infections. We evaluated both tests in 134 unselected febrile children admitted to the General Hospital Kota Bharu, Malaysia. The children were divided into two groups: (i) those who were blood and/or stool culture positive for S. typhi and/or who had clinical features strongly suggestive of enteric fever (n = 62); and (ii) those who were both culture-negative and had clinical evidence of another diagnosis (n = 72). The sensitivity and specificity of the Typhidot and Typhidot-M tests were identical at 90.3 and 93.1%, respectively. Both tests had comparable sensitivity but greater specificity than those of the Widal test (91.9 and 80.6%, respectively). When used together, a positive result for Typhidot and/or Typhidot-M was more specific than either test alone (95.2%) but specificity was lower (87.5%). We conclude that the Typhidot and Typhidot-M tests have comparatively high diagnostic accuracy, suggesting that IgM can be detected in children who may have a predominant IgG response to S. typhi. Using these tests in combination increases the negative predictive value but at the cost of a lower positive predictive value.
    Matched MeSH terms: Immunoglobulin G/blood
  10. A recombinant antigen-based IgG4 ELISA for the specific and sensitive detection of Brugia malayi infection
    Rahmah N, Lim BH, Khairul Anuar A, Shenoy RK, Kumaraswami V, Lokman Hakim S, et al.
    Trans R Soc Trop Med Hyg, 2001 8 9;95(3):280-4.
    PMID: 11490997
    An IgG4 ELISA based on a novel recombinant antigen was evaluated for detection of Brugia malayi infection, using 2487 sera from various institutions: 2031 samples from Universiti Sains Malaysia, 276 blinded sera from 2 other institutions in Malaysia, 140 blinded sera from India and 40 blinded sera from Thailand. These sera were from various groups of individuals, i.e., microfilaraemics, chronic patients, endemic normals, non-endemic normals and individuals with other parasitic and bacterial infections. Based on a cut-off optical density reading of 0.300, the IgG4 ELISA demonstrated specificity rates of 95.6-100%, sensitivity rates of 96-100%, positive predictive values of 75-100% and negative predictive values of 98.9-100%. These evaluation studies demonstrated the high specificity and sensitivity of this test for the detection of active B. malayi infection. Thus, the IgG4 ELISA would be very useful as a tool in diagnosis and in elimination programmes for brugian filariasis.
    Matched MeSH terms: Immunoglobulin G/blood*
  11. Diagnosis of nipah virus encephalitis by electron microscopy of cerebrospinal fluid
    Chow VT, Tambyah PA, Yeo WM, Phoon MC, Howe J
    J Clin Virol, 2000 Dec;19(3):143-7.
    PMID: 11090749
    BACKGROUND: between 1998 and 1999, an outbreak of potentially fatal viral encephalitis erupted among pig farm workers in West Malaysia, and later spread to Singapore where abattoir workers were afflicted. Although Japanese encephalitis virus was initially suspected, the predominant aetiologic agent was subsequently confirmed to be Nipah virus, a novel paramyxovirus related to but distinct from Hendra virus.

    OBJECTIVE: to describe a case of Nipah virus encephalitis in a pig farm worker from Malaysia.

    STUDY DESIGN: the clinical, laboratory and radiological findings of this patient were scrutinized. Special emphasis was placed on the electron microscopic analysis of the cerebrospinal fluid (CSF) specimen from this patient.

    RESULTS: the neurological deficits indicative of cerebellar involvement were supported by the magnetic resonance imaging that showed prominent cerebellar and brainstem lesions. CSF examination provided further evidence of viral encephalitis. Complement fixation and/or RT-PCR assays were negative for Japanese encephalitis, herpes simplex, measles and mumps viruses. ELISA for detecting IgM and IgG antibodies against Hendra viral antigens were equivocal for the CSF specimen, and tested initially negative for the first serum sample but subsequently positive for the repeat serum sample. Transmission electron microscopy of negatively-stained preparations of CSF revealed enveloped virus-like structures fringed with surface projections as well as nucleocapsids with distinctive helical and herringbone patterns, features consistent with those of other paramyxoviruses, including Hendra virus.

    CONCLUSION: this case report reiterates the relevant and feasible role of diagnostic electron microscopy for identifying and/or classifying novel or emerging viral pathogens for which sufficiently specific and sensitive tests are lacking.

    Matched MeSH terms: Immunoglobulin G/blood
  12. Levels of serum IgG against Porphyromonas gingivalis in patients with rapidly progressive periodontitis, rheumatoid arthritis and adult periodontitis
    Yusof Z, Porter SR, Greenman J, Scully C
    J Nihon Univ Sch Dent, 1995 Dec;37(4):197-200.
    PMID: 8820338
    Levels of serum IgG against Porphyromonas gingivalis cell sonicate were determined in patients with rheumatoid arthritis (RA) (n = 25), rapidly progressive periodontitis (RPP)(n = 25) and adult periodontitis (AP)(n = 15) and controls (HP)(n = 10) utilizing the ELISA technique. Comparison between groups showed no significant differences between the HP and RA groups and also between the RPP and AP groups. The increased levels of IgG in the RPP and AP groups were comparable. Significant differences in IgG levels were noted between HP and RPP (p<0.05) and between HP and AP (p<0.01). The differences between RA and RPP and between RA and AP were highly significant (p<0.0001). Thus it was revealed that the serum levels of IgG against P. gingivalis in RPP and AP patients were elevated, whereas the levels in RA patients were comparable to those in controls.
    Matched MeSH terms: Immunoglobulin G/blood*
  13. Antibody reactivity with two strains of human herpesvirus-6 in Malaysians
    Yadav M, Umamaheswari S, Ablashi D
    J Med Virol, 1991 Apr;33(4):236-9.
    PMID: 1649908
    A total of 234 sera from healthy Malaysians of diverse ethnic origins were tested for antibody to the Z29 and prototype GS strains of HHV-6. The prevalence in the races ranged from 58 to 80% for the GS strain and 49 to 76% for the Z29 strain. The highest prevalence was in Malays with semi-urban cultural lifestyles and lowest was in the indigenous rural tribes (Ibans, Kadazans, Bidayuhs, and Orang Asli). The antibody titres to GS and Z29 virus capsid antigens differed in 11 (4.7%) samples by more than 2 dilutions. In 9 of the 11 sera the titres to GS strain were higher than to the Z29 strain. The differences in the antibody titres between strains of HHV-6 may reflect subtle changes in antigen structure of the virus recognised by some individuals.
    Matched MeSH terms: Immunoglobulin G/immunology
  14. Multi-laboratory evaluation of a scrub typhus diagnostic kit
    Kelly DJ, Wong PW, Gan E, Chye CT, Cowan D, Lewis GE
    Am J Trop Med Hyg, 1990 Sep;43(3):301-7.
    PMID: 2121057
    Scrub typhus is a major cause of febrile illness throughout the Asia-Pacific region. It is commonly undiagnosed, partly because of the lack of a simple, reliable diagnostic test which can be used in clinical laboratories. The indirect immunoperoxidase technique, configured into a test kit, was provided to technicians who were trained in its use. They used the kit during a 2 year field trial in their respective clinical hospital laboratories throughout Malaysia. In an evaluation using 1,722 consecutive sera tested in those laboratories, the kit was found to have a median sensitivity for IgG detection of 0.85 (range 0.33-0.95), a median specificity of 0.94 (range 0.88-1.00), reproducibility of 0.86, and efficiency of 0.92 when compared to the reference laboratory. In a proficiency survey in which 10 laboratories received 3 coded test samples, all but 2 laboratories had results within 1 dilution of the reference laboratory in quantitating specific IgG, whereas 7 laboratories were within 1 dilution in quantitating IgM. The shelf life of the kit was at least 1 year at 4 degrees C.
    Matched MeSH terms: Immunoglobulin G/analysis
  15. Rickettsia tsutsugamushi antibody in mother/cord pairs of sera
    Shirai A, Brown GW, Gan E, Huxsoll DL, Groves MG
    Jpn. J. Med. Sci. Biol., 1981 Feb;34(1):37-9.
    PMID: 6790744
    Matched MeSH terms: Immunoglobulin G/analysis
  16. Chlamydia pneumoniae IgG seropositivity and clinical history of ischemic heart disease in Singapore
    Koh WP, Taylor MB, Chew SK, Phoon MC, Kang KL, Chow VT
    J Microbiol Immunol Infect, 2003 Sep;36(3):169-74.
    PMID: 14582560
    There is still substantial uncertainty concerning the association between Chlamydia pneumoniae and ischemic heart disease. This may partly be explained by the adjustment for potential confounders in different population studies. This is the first study in Singapore to look at the association of C. pneumoniae seropositivity with ischemic heart disease in a multivariate analysis. A random sample of 714 persons aged between 35 and 69 years was selected from the participants of the Singapore National Health Survey conducted in 1998. Data on clinical measurements and conditions were collected using biochemical tests and interviewer-based questionnaires. Ischemic heart disease was defined by the Rose questionnaire and included history suggestive of angina and/or myocardial infarction. Immunoglobulin G antibodies for C. pneumoniae were detected using an indirect microimmunofluorescence test, and seropositivity was defined as IgG titers > or = 1:16. There were no statistically significant differences in the prevalence rates of seropositivity to C. pneumoniae among the three ethnic groups, that is, Chinese (80.4%), Malays (74.0%), and Asian Indians (73.2%). There was no association between seropositivity and ischemic heart disease after adjustment for age alone (OR 1.00, 95% CI 0.54-1.83) or for age, sex, and other risk factors of atherosclerosis (OR 0.99, 95% CI 0.53-1.84). C. pneumoniae Immunoglobulin G seropositivity was not associated with an increased risk of ischemic heart disease as defined by the Rose angina questionnaire in Singapore.
    Matched MeSH terms: Immunoglobulin G/blood*
  17. A case of congenital malaria in Malaysia with IgM malaria antibodies
    Thomas V, Chit CW
    Trans R Soc Trop Med Hyg, 1980;74(1):73-6.
    PMID: 7001686
    Congenital malaria from Malaysia is reported here for the first time. It occurred in a baby boy born to a 16-year-old primigravida who contracted Plasmodium falciparum infection during pregnancy. She suffered malaria during the later stages of pregnancy and at parturition. The placenta was heavily infested with various asexual stages of P. falciparum. Gametocytes were not seen. Extensive search did not show other species. Cord blood showed very light infection with young trophozoites of P. falciparum. Serological studies using IFA technique showed specific IgG and IgM antibodies to P. falciparum in maternal cord and two early neonatal sera. These serum samples showed lower levels of IgG antibodies against P. vivax and P. malariae, but there were no specific IgM antibodies against these species. The value of specific IgM antibody in the diagnosis of congenital malaria is discussed.
    Matched MeSH terms: Immunoglobulin G/analysis
  18. Levels of plasma immunoglobulins in Malaysians
    Shah FH, Yadav M
    Southeast Asian J. Trop. Med. Public Health, 1973 Dec;4(4):468-73.
    PMID: 4207078
    Matched MeSH terms: Immunoglobulin G/analysis
  19. Rubella-related intermediate uveitis in pregnancy--a rare presentation
    Thirupathy A, Tajunisah I
    Ocul Immunol Inflamm, 2011 Jun;19(3):156-7.
    PMID: 21595530 DOI: 10.3109/09273948.2011.555593
    To report a rare case of intermediate uveitis following rubella infection in pregnancy.
    Matched MeSH terms: Immunoglobulin G/blood
  20. Fulltext IgM in human immunity to Plasmodium falciparum malaria
    Boyle MJ, Chan JA, Handayuni I, Reiling L, Feng G, Hilton A, et al.
    Sci Adv, 2019 09;5(9):eaax4489.
    PMID: 31579826 DOI: 10.1126/sciadv.aax4489
    Most studies on human immunity to malaria have focused on the roles of immunoglobulin G (IgG), whereas the roles of IgM remain undefined. Analyzing multiple human cohorts to assess the dynamics of malaria-specific IgM during experimentally induced and naturally acquired malaria, we identified IgM activity against blood-stage parasites. We found that merozoite-specific IgM appears rapidly in Plasmodium falciparum infection and is prominent during malaria in children and adults with lifetime exposure, together with IgG. Unexpectedly, IgM persisted for extended periods of time; we found no difference in decay of merozoite-specific IgM over time compared to that of IgG. IgM blocked merozoite invasion of red blood cells in a complement-dependent manner. IgM was also associated with significantly reduced risk of clinical malaria in a longitudinal cohort of children. These findings suggest that merozoite-specific IgM is an important functional and long-lived antibody response targeting blood-stage malaria parasites that contributes to malaria immunity.
    Matched MeSH terms: Immunoglobulin G/immunology
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