Displaying publications 41 - 60 of 1044 in total

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  1. Fulltext The experience with fine needle aspiration cytology in the management of palpable breast lumps in the University Hospital Kuala Lumpur
    Yip CH, Jayaram G, Alhady SF
    Med J Malaysia, 2000 Sep;55(3):363-7.
    PMID: 11200718
    A total of 676 palpable breast lumps seen in the Breast Clinic, University Hospital, Kuala Lumpur from August 1993 to August 1994 were subjected to fine needle aspiration cytology. Fifty-four were reported as inadequate, 501 benign, 95 malignant and 26 suspicious. One hundred and eighty-seven aspirates had histological correlation, while 34 of the malignant aspirates had clinical correlation. The majority of the other 455 patients were followed up for a period of 60 to 72 months without any malignancies becoming apparent. For analysis, only the 221 cases with histological or clinical correlation were included, (the suspicious category was included into the positive group and the inadequate cases were excluded), giving a sensitivity of 91.7%, a specificity of 91.7% and a diagnostic accuracy of 91.7%. Breast cytology was an accurate and rapid method of diagnosis of breast diseases, and in a busy surgical unit with limited operating time, it allowed for the triage of patients with breast complaints in deciding which cases needed early open biopsy. A negative cytology does not exclude the possibility of cancer, as there was a false negative rate of 11%. However by utilising a diagnostic triad of clinical examination, radiological assessment and fine needle aspiration cytology, the risk of missing a malignancy is small.
    Matched MeSH terms: Sensitivity and Specificity
  2. Random walker with improved weighting function for interactive medical image segmentation
    Yin LK, Rajeswari M
    Biomed Mater Eng, 2014;24(6):3333-41.
    PMID: 25227043 DOI: 10.3233/BME-141156
    To segment an image using the random walks algorithm; users are often required to initialize the approximate locations of the objects and background in the image. Due to its segmenting model that is mainly reflected by the relationship among the neighborhood pixels and its boundary conditions, random walks algorithm has made itself sensitive to the inputs of the seeds. Instead of considering the relationship between the neighborhood pixels solely, an attempt has been made to modify the weighting function that accounts for the intensity changes between the neighborhood nodes. Local affiliation within the defined neighborhood region of the two nodes is taken into consideration by incorporating an extra penalty term into the weighting function. Besides that, to better segment images, particularly medical images with texture features, GLCM variance is incorporated into the weighting function through kernel density estimation (KDE). The probability density of each pixel belonging to the initialized seeds is estimated and integrated into the weighting function. To test the performance of the proposed weighting model, several medical images that mainly made up of 174-brain tumor images are experimented. These experiments establish that the proposed method produces better segmentation results than the original random walks.
    Matched MeSH terms: Sensitivity and Specificity
  3. Internal radiation dosimetry of orally administered radiotracers for the assessment of gastrointestinal motility
    Yeong CH, Ng KH, Abdullah BJJ, Chung LY, Goh KL, Perkins AC
    Appl Radiat Isot, 2014 Dec;94:216-220.
    PMID: 25222875 DOI: 10.1016/j.apradiso.2014.08.009
    Radionuclide imaging using (111)In, (99m)Tc and (153)Sm is commonly undertaken for the clinical investigation of gastric emptying, intestinal motility and whole gut transit. However the documented evidence concerning internal radiation dosimetry for such studies is not readily available. This communication documents the internal radiation dosimetry for whole gastrointestinal transit studies using (111)In, (99m)Tc and (153)Sm labeled formulations. The findings were compared to the diagnostic reference levels recommended by the United Kingdom Administration of Radioactive Substances Advisory Committee, for gastrointestinal transit studies.
    Matched MeSH terms: Sensitivity and Specificity
  4. Pilot study of the sensitivity and specificity of the DNA integrity assay for stool-based detection of colorectal cancer in Malaysian patients
    Yehya AH, Yusoff NM, Khalid IA, Mahsin H, Razali RA, Azlina F, et al.
    Asian Pac J Cancer Prev, 2012;13(5):1869-72.
    PMID: 22901138
    BACKGROUND: To assess the diagnostic potential of tumor-associated high molecular weight DNA in stool samples of 32 colorectal cancer (CRC) patients compared to 32 healthy Malaysian volunteers by means of polymerase chain reaction (PCR).

    METHODS: Stool DNA was isolated and tumor-associated high molecular weight DNA (1.476 kb fragment including exons 6-9 of the p53 gene) was amplified using PCR and visualized on ethidium bromide-stained agarose gels.

    RESULTS: Out of 32 CRC patients, 18 were positive for the presence of high molecular weight DNA as compared to none of the healthy individuals, resulting in an overall sensitivity of 56.3% with 100% specificity. Out of 32 patients, 23 had tumor on the left side and 9 on the right side, 16 and 2 being respectively positive. This showed that high molecular weight DNA was significantly (p=0.022) more detectable in patients with left side tumor (69.6% vs 22.2%). Out of 32 patients, 22 had tumors larger than 1.0 cm, 18 of these (81.8%) being positive for long DNA as compared to not a single patient with tumor size smaller than 1.0 cm (p<0.001).

    CONCLUSION: We detected CRC-related high molecular weight p53 DNA in stool samples of CRC patients with an overall sensitivity of 56.3% with 100% specificity, with a strong tumor size dependence.

    Matched MeSH terms: Sensitivity and Specificity
  5. Prevalence of latex allergy may be vastly overestimated when determined by in vitro assays
    Yeang HY
    Ann. Allergy Asthma Immunol., 2000 Jun;84(6):628-32.
    PMID: 10875493 DOI: 10.1016/S1081-1206(10)62415-5
    BACKGROUND:
    The prevalence of latex-specific IgE computed from the results of serologic assays is commonly thought to reflect, to a greater or lesser extent, the prevalence of latex allergy and its implied risk.

    OBJECTIVE:
    The study examines how imperfect test specificity of in vitro assays influences the precision of latex allergy prevalence that it estimates.

    METHODS:
    Various models encompassing a range of hypothetical test sensitivity and specificity values are investigated to gauge their influence on the estimate of latex allergy prevalence. The models examine these interactions in situations of high or low allergy prevalence.

    RESULTS:
    Serologic latex diagnostic assays with test specificity within the range of those of commercially available assays can greatly overestimate prevalence where the true prevalence is low (eg, of the order of one in 100 or one in 1,000). A formula to correct for errors in prevalence estimates arising from imperfect test sensitivity and specificity of an in vitro assay is presented.

    CONCLUSION:
    While serologic assays for latex IgE pose few hazards to the patient and are useful for confirming the diagnosis of latex allergy, the test results may vastly overestimate the true prevalence of latex allergy and its associated risks in situations where latex allergy is actually rare.
    Matched MeSH terms: Sensitivity and Specificity
  6. Allergen concentration in natural rubber latex
    Yeang HY, Hamilton RG, Bernstein DI, Arif SA, Chow KS, Loke YH, et al.
    Clin Exp Allergy, 2006 Aug;36(8):1078-86.
    PMID: 16911364 DOI: 10.1111/j.1365-2222.2006.02531.x
    BACKGROUND:
    Hevea brasiliensis latex serum is commonly used as the in vivo and in vitro reference antigen for latex allergy diagnosis as it contains the full complement of latex allergens.

    OBJECTIVE:
    This study quantifies the concentrations of the significant allergens in latex serum and examines its suitability as an antigen source in latex allergy diagnosis and immunotherapy.

    METHODS:
    The serum phase was extracted from centrifuged latex that was repeatedly freeze-thawed or glycerinated. Quantitation of latex allergens was performed by two-site immunoenzymetric assays. The abundance of RNA transcripts of the latex allergens was estimated from the number of their clones in an Expressed Sequence Tags library.

    RESULTS:
    The latex allergens, Hev b 1, 2, 3, 4, 5, 6, 7 and 13, were detected in freeze-thawed and glycerinated latex serum at levels ranging from 75 (Hev b 6) to 0.06 nmol/mg total proteins (Hev b 4). Hev b 6 content in the latex was up to a thousand times higher than the other seven latex allergens, depending on source and/or preparation procedure. Allergen concentration was reflected in the abundance of mRNA transcripts. When used as the antigen, latex serum may bias the outcome of latex allergy diagnostic tests towards sensitization to Hev b 6. Tests that make use of latex serum may fail to detect latex-specific IgE reactivity in subjects who are sensitized only to allergens that are present at low concentrations.

    CONCLUSION:
    Latex allergy diagnostics and immunotherapy that use whole latex serum as the antigen source may not be optimal because of the marked imbalance of its constituent allergens.
    Matched MeSH terms: Sensitivity and Specificity
  7. Enzyme-linked amperometric electrochemical genosensor assay for the detection of PCR amplicons on a streptavidin-treated screen-printed carbon electrode
    Yean CY, Kamarudin B, Ozkan DA, Yin LS, Lalitha P, Ismail A, et al.
    Anal Chem, 2008 Apr 15;80(8):2774-9.
    PMID: 18311943 DOI: 10.1021/ac702333x
    A general purpose enzyme-based amperometric electrochemical genosensor assay was developed wherein polymerase chain reaction (PCR) amplicons labeled with both biotin and fluorescein were detected with peroxidase-conjugated antifluorescein antibody on a screen-printed carbon electrode (SPCE). As a proof of principle, the response selectivity of the genosensor was evaluated using PCR amplicons derived from lolB gene of Vibrio cholerae. Factors affecting immobilization, hybridization, and nonspecific binding were optimized to maximize sensitivity and reduce assay time. On the basis of the background amperometry signals obtained from nonspecific organisms and positive signals obtained from known V. cholerae, a threshold point of 4.20 microA signal was determined as positive. Under the optimum conditions, the limit of detection (LOD) of the assay was 10 CFU/mL of V. cholerae. The overall precision of this assay was good, with the coefficient of variation (CV) being 3.7% using SPCE and intermittent pulse amperometry (IPA) as an electrochemical technique. The assay is sensitive, safe, and cost-effective when compared to conventional agarose gel electrophoresis, real-time PCR, and other enzyme-linked assays for the detection of PCR amplicons. Furthermore, the use of a hand-held portable reader makes it suitable for use in the field.
    Matched MeSH terms: Sensitivity and Specificity
  8. A nanoplex PCR assay for the rapid detection of vancomycin and bifunctional aminoglycoside resistance genes in Enterococcus species
    Yean CY, Yin LS, Lalitha P, Ravichandran M
    BMC Microbiol, 2007 Dec 11;7:112.
    PMID: 18070365
    BACKGROUND: Enterococci have emerged as a significant cause of nosocomial infections in many parts of the world over the last decade. The most common enterococci strains present in clinical isolates are E. faecalis and E. faecium which have acquired resistant to either gentamicin or vancomycin. The conventional culture test takes 2-5 days to yield complete information of the organism and its antibiotic sensitivity pattern. Hence our present study was focused on developing a nanoplex PCR assay for the rapid detection of vancomycin and bifunctional aminoglycoside resistant enterococci (V-BiA-RE). This assay simultaneously detects 8 genes namely 16S rRNA of Enterococcus genus, ddl of E. faecalis and E. faecium, aacA-aphD that encodes high level gentamicin resistance (HLGR), multilevel vancomycin resistant genotypes such as vanA, vanB, vanC and vanD and one internal control gene.

    RESULTS: Unique and specific primer pairs were designed to amplify the 8 genes. The specificity of the primers was confirmed by DNA sequencing of the nanoplex PCR products and BLAST analysis. The sensitivity and specificity of V-BiA-RE nanoplex PCR assay was evaluated against the conventional culture method. The analytical sensitivity of the assay was found to be 1 ng at the DNA level while the analytical specificity was evaluated with 43 reference enterococci and non-enterococcal strains and was found to be 100%. The diagnostic accuracy was determined using 159 clinical specimens, which showed that 97% of the clinical isolates belonged to E. faecalis, of which 26% showed the HLGR genotype, but none were vancomycin resistant. The presence of an internal control in the V-BiA-RE nanoplex PCR assay helped us to rule out false negative cases.

    CONCLUSION: The nanoplex PCR assay is robust and can give results within 4 hours about the 8 genes that are essential for the identification of the most common Enterococcus spp. and their antibiotic sensitivity pattern. The PCR assay developed in this study can be used as an effective surveillance tool to study the prevalence of enterococci and their antibiotic resistance pattern in hospitals and farm animals.

    Matched MeSH terms: Sensitivity and Specificity
  9. Prealbumin rather than albumin is a more sensitive indicator of acute liver disease
    Yasmin MY, Aziz B, Nazim M, Madhavan RK
    Malays J Pathol, 1993 Dec;15(2):147-50.
    PMID: 8065177
    The changes in serum prealbumin (transthyretin) and serum albumin in acute and chronic liver diseases were investigated. Albumin has long been used as a useful indicator of liver function but serum prealbumin has recently been noted for its clinical significance in acute liver diseases. Serum prealbumin concentrations and liver function tests (albumin, bilirubin, alanine aminotransferase) were determined on blood obtained from normal donors (n = 148) and from patients suffering from liver diseases (n = 78) such as acute viral hepatitis, chronic active hepatitis, cirrhosis and hepatoma. The mean serum prealbumin concentration in normal subjects was 29.6 +/- 4.82 mg/dl while the mean serum prealbumin concentration in patients with liver disease was greatly reduced (acute viral hepatitis = 15.3 +/- 7.4mg/dl; chronic active hepatitis = 10.2 +/- 6.6mg/dl; cirrhosis = 9.9 +/- 6.4mg/dl and hepatoma = 10.7 +/- 4.2). Albumin concentrations dropped slightly (13% compared to control) in acute viral hepatitis but dropped markedly (28% compared to control) in chronic liver diseases. The study suggests that serum prealbumin concentration might be a more sensitive indicator than albumin in assessing liver dysfunction in acute liver diseases.
    Matched MeSH terms: Sensitivity and Specificity
  10. Fulltext Combined assessment of TGF-beta-1 and alpha-fetoprotein values improves specificity in the diagnosis of hepatocellular carcinoma and other chronic liver diseases in Malaysia
    Yasmin Anum MY, Looi ML, Nor Aini AH, Merican I, Wahidah A, Mohd Radzi AH, et al.
    Med J Malaysia, 2009 Sep;64(3):223-7.
    PMID: 20527273 MyJurnal
    Transforming growth factor beta-1 (TGF-beta-1) is a multifunctional cytokine involved in the regulation of growth and differentiation of both normal and transformed cells. The main aim of this study was to determine whether TGF-beta-1 or alpha fetoprotein (AFP) or the combination of the two is a better indicator for hepatocellularcarcinoma (HCC). Serum TGF-beta-1 and AFP were measured by ELISA in 40 healthy subjects, 23 patients with hepatocellular carcinoma (HCC), 70 patients with hepatitis B, 26 patients with hepatitis C and 16 patients with liver cirrhosis (LC). Patients with liver diseases showed significantly higher serum TGF-beta-1 values (> 3 fold) compared to control subjects. As for serum AFP, significant elevation was only observed for HCC cases. Serum TGF-beta-1 exhibited higher percent sensitivity compared to serum AFP in all liver diseases. Combination of serum TGF-beta-1 and AFP increased specificities in all cases studied. In conclusion, serum TGF-beta-1 is a more sensitive marker for HCC when compared to serum AFP and its specificity is increased when combined with serum AFP.
    Matched MeSH terms: Sensitivity and Specificity
  11. Epstein-Barr virus DNA detection in the diagnosis of nasopharyngeal carcinoma
    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: Sensitivity and Specificity
  12. Fulltext Predicting need for intensive care unit admission in adult emphysematous pyelonephritis patients at emergency departments: comparison of five scoring systems
    Yap XH, Ng CJ, Hsu KH, Chien CY, Goh ZNL, Li CH, et al.
    Sci Rep, 2019 11 12;9(1):16618.
    PMID: 31719593 DOI: 10.1038/s41598-019-52989-7
    This study assesses the performance of National Early Warning Score (NEWS), Quick Sepsis-related Organ Failure Assessment (qSOFA), Modified Early Warning Score (MEWS), Rapid Emergency Medicine Score (REMS), and Rapid Acute Physiology Score (RAPS) in predicting emphysematous pyelonephritis (EPN) patients' need for intensive care unit (ICU) admission. A retrospective analysis was conducted at four training and research hospitals' emergency departments (EDs) on all EPN adult patients from January 2007 to August 2017. Data extracted were used to calculate raw scores for five physiologic scoring systems. Mann-Whitney U tests and χ2 tests were done for numerical and categorical variables respectively to examine differences between characteristics of ICU and non-ICU patient populations. Predictability of ICU admission was evaluated with AUROC analysis. ICU patients had lower GCS scores, SpO2, platelet counts, and estimated glomerular filtration rate; and higher bands, blood urea nitrogen, creatinine, and incidences of septic shock and nephrectomy. NEWS performed best, with 73.85% accuracy at optimal cut-off of 3. In this multicentre ED EPN series, we recommend using NEWS in early identification of critical EPN patients and advance planning for ICU admission. This would reduce delays in ICU transfer and ultimately improve patient outcomes.
    Matched MeSH terms: Sensitivity and Specificity
  13. Simple high-performance liquid chromatographic method for the determination of tocotrienols in human plasma
    Yap SP, Julianto T, Wong JW, Yuen KH
    J Chromatogr B Biomed Sci Appl, 1999 Dec 10;735(2):279-83.
    PMID: 10670741
    A simple high-performance liquid chromatographic method using fluorescence detection was developed for the determination of vitamin E especially delta-, gamma- and alpha-tocotrienols in human plasma. The method entailed direct injection of plasma sample after deproteinization using a 3:2 mixture of acetonitrile-tetrahydrofuran. The mobile phase comprised 0.5% (v/v) of distilled water in methanol. Analyses were run at a flow-rate of 1.5 ml/min with the detector operating at an excitation wavelength of 296 nm and emission wavelength of 330 nm. This method is specific and sensitive, with a quantification limit of approximately 40, 34 and 16 ng/ml for alpha-, gamma- and delta-tocotrienol, respectively. The mean absolute recovery values were about 98% while the within-day and between-day relative standard deviation and percent error values of the assay method were all less than 12.0% for alpha-, gamma- and delta-tocotrienol. The calibration curve was linear over a concentration range of 40-2500, 30-4000 and 16-1000 ng/ml for alpha-, gamma- and delta-tocotrienol, respectively. Application of the method in a bioavailability study for determination of the above compounds was also demonstrated.
    Matched MeSH terms: Sensitivity and Specificity
  14. HTLV-I antibody study in normal individuals and unselected hospital patients in Malaysia
    Yap SF, Peh SC, Chan L, Wong HC, How VJ, Looi LM
    Southeast Asian J. Trop. Med. Public Health, 1992 Mar;23(1):26-9.
    PMID: 1355930
    A serological investigation for human T cell leukemia virus I (HTLV-I) infection was carried out at the University Hospital, Kuala Lumpur. A total of 626 sera from a non-patient population and 1,038 sera from unselected in-patients were screened for HTLV-I antibodies using an enzyme-linked immunosorbent assay (ELISA). 27/1664 (1.6%) were found to be reactive. However, on Western blotting, only 2 sera were confirmed positive, both showing reactions for the major core (p19 and p24) and the envelope (gp46) proteins. Both of the serum samples were from unselected hospital patients. Most of the remaining sera which were reactive on screening showed indeterminate results on Western blotting. These were further tested by radioimmunoprecipitation assay (RIPA) and none of these sera gave a positive reaction. Therefore, only 2/1038 (0.19%) unselected patients could be confirmed to have antibodies to HTLV-I. None of the normal individuals screened showed a positive Western blot result. Our data indicate that HTLV-I infection is present in our population, but at a low prevalence rate.
    Matched MeSH terms: Sensitivity and Specificity
  15. Hybridisation analysis for serum hepatitis B virus DNA
    Yap SF, Wong PW, Kenneth-Raj
    Br J Biomed Sci, 1994 Dec;51(4):336-40.
    PMID: 7756940
    A study was carried out to determine optimal assay conditions for an in-house hybridisation assay for detection of hepatitis B virus (HBV) genome in serum samples. Pre-treatment of samples, blot treatment and hybridisation conditions were found to affect assay performance. The indirect serum blot procedure was more robust and reliable than direct serum blotting. In the former, viral particles were isolated from the sample, lysed and then extracted. In comparison, no approaches to the direct serum spot method performed adequately. Sensitivity studies showed that labelling of the nucleic acid probe with dCTP was more efficient than with dATP. Using probes labelled to a specific activity of > 1 x 10(8) and an autoradiography period of about 48 h we could achieve a detection limit of < 1 pg. Specificity was achieved by use of a highly purified probe and moderately stringent hybridisation and wash conditions. Background binding was minimal and there was no non-specific binding of probe to negative control samples. Factors affecting speed of the assay were studied to identify steps that could be modified to shorten assay time without sacrificing performance. A shorter centrifugation step and the use of a high specific-activity probe permitted completion of an assay within four days.
    Matched MeSH terms: Sensitivity and Specificity
  16. Molecular analysis of Cryptosporidium from cattle from five states of Peninsular Malaysia
    Yap NJ, Koehler AV, Ebner J, Tan TK, Lim YA, Gasser RB
    Mol Cell Probes, 2016 Feb;30(1):39-43.
    PMID: 26775614 DOI: 10.1016/j.mcp.2016.01.002
    Despite the importance of the cattle industry in Malaysia, there are very few studies of the diversity and public health significance of bovine cryptosporidiosis in this country. In the present study, we used a PCR-based approach to detect and genetically characterize Cryptosporidium DNA in faecal samples from a cohort of 215 asymptomatic cattle (of different ages) from six farms from five states of Peninsular Malaysia. Cattle on four of the six farms were test-positive for Cryptosporidium, with an overall prevalence of 3.2%. Cryptosporidium bovis and Cryptosporidium ryanae were detected in two (0.9%) and five (2.3%) samples tested; this low prevalence likely relates to the age of the cattle tested, as most (73%) of the samples tested originated from cattle that were ≥2 years of age. Future studies should investigate the zoonotic potential of Cryptosporidium in pre-weaned and weaned calves in rural communities of Malaysia.
    Matched MeSH terms: Sensitivity and Specificity
  17. An evaluation of the staphylococcal co-agglutination test for the detection of group A rotavirus in human faeces
    Yap KL, Ooi YE, Khor CM, Wong SH
    Malays J Pathol, 1992 Dec;14(2):105-10.
    PMID: 1338997
    The group A rotavirus staphylococcal co-agglutination test was evaluated and its sensitivity and specificity compared with an in-house enzyme-linked immunosorbent assay (ELISA) and a commercial latex agglutination test (Rotalex). In addition, the storage stability of the staphylococcal reagents was ascertained. Examination of 136 clarified suspensions of diarrhoeal faeces by the staphylococcal co-agglutination test revealed a high proportion of false positives (26%) and uninterpretable results (34%) due to non-specific agglutination. Non-specific agglutination could be removed effectively by prior absorption of the clarified faecal specimens with unsensitized staphylococci. The staphylococcal co-agglutination test was less sensitive and specific than the in-house enzyme-linked immunosorbent assay but was comparable to the Rotalex slide latex agglutination test. The staphylococcal reagents have a shelf life of at least 29 weeks.
    Matched MeSH terms: Sensitivity and Specificity
  18. Development of a slide latex agglutination test for rotavirus antigen detection
    Yap KL
    Malays J Pathol, 1994 Jun;16(1):49-56.
    PMID: 16329576
    The aim of this study was to optimize the conditions for the passive adsorption of polyclonal antibody onto plain surface polystyrene latex particles and its performance in a slide latex agglutination test for rotavirus antigen detection. Cleaning of latex particles by washing through repetitive centrifuging, decanting and resuspending in distilled water was adequate in removing surfactants from the particles' surfaces to enable coating. A study of antibody concentration, incubation temperature and buffer pH revealed that optimum coating was achieved with a 3-fold excess of antibody to the calculated total particle surface capacity for the antibody in a glycine-saline buffer of pH 9.2 at 40 degrees C for 4 hours. The ionic strength and pH of the latex suspending buffer and the sample buffer were critical factors determining the sensitivity of the test and the appearance of non-specific agglutination. Ultrasonication, addition of glycerol and Tween 20, either individually or in combination, were able to suppress non-specific agglutination in some batches of latex reagents. Polyethylene glycol 6000 enhanced the quality of agglutination as well as reduced the time of its appearance, especially in reagents that produced poor agglutination.
    Matched MeSH terms: Sensitivity and Specificity
  19. Can the byssus of green-lipped mussel Perna viridis (Linnaeus) from the west coast of Peninsular Malaysia be a biomonitoring organ for Cd, Pb and Zn? Field and laboratory studies
    Yap CK, Ismail A, Tan SG
    Environ Int, 2003 Jul;29(4):521-8.
    PMID: 12705949
    Concentrations of cadmium (Cd), lead (Pb) and zinc (Zn) in total soft tissues (ST) and byssus (BYS) of the green-lipped mussel Perna viridis from 11 different geographical locations off the west coast of Peninsular Malaysia were determined. The metal concentrations distributed between the BYS and ST were compared. The results of this study indicated that higher levels of Cd (1.31 microg/g), Pb (38.49 microg/g) and Zn (206.52 microg/g) were accumulated in the BYS than in the total ST (Cd: 0.29 microg/g; Pb: 8.27 microg/g; Zn: 102.6 microg/g). Semi-static and short period controlled laboratory experiments were also conducted for the accumulation and depuration of Cd, Pb and Zn in the total ST and BYS of P. viridis. The ratios (BYS/ST) for Pb and Cd from the laboratory experiments showed that the total ST accumulated more metals than the BYS. Therefore, these laboratory results disagreed with those found for the field samples. However, the laboratory results for the Zn ratio (BYS/ST) agreed with those of the field samples. It was evident that when compared to the ST, the BYS was a more sensitive biomonitoring organ for Zn while it could be a complementary organ for Cd and Pb in the total ST. Since total ST of P. viridis had been reported to have regulative mechanism for Zn, its BYS can be used as a biomonitoring organ for the identification of coastal areas exposed to Zn pollution.
    Matched MeSH terms: Sensitivity and Specificity
  20. Fulltext A coumarin-based fluorescent probe as a central nervous system disease biomarker
    Yap AC, Mahamad UA, Lim SY, Kim HJ, Choo YM
    Sensors (Basel), 2014 Nov 10;14(11):21140-50.
    PMID: 25390405 DOI: 10.3390/s141121140
    Homocysteine and methylmalonic acid are important biomarkers for diseases associated with an impaired central nervous system (CNS). A new chemoassay utilizing coumarin-based fluorescent probe 1 to detect the levels of homocysteine is successfully implemented using Parkinson's disease (PD) patients' blood serum. In addition, a rapid identification of homocysteine and methylmalonic acid levels in blood serum of PD patients was also performed using the liquid chromatography-mass spectrometry (LC-MS). The results obtained from both analyses were in agreement. The new chemoassay utilizing coumarin-based fluorescent probe 1 offers a cost- and time-effective method to identify the biomarkers in CNS patients.
    Matched MeSH terms: Sensitivity and Specificity
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