MyMedR

Displaying all 13 publications

Abstract:

Sort:

Response: importance of screening for macroprolactin in hyperprolactinaemic sera

Jamaluddin FA

Malays J Pathol, 2013 Dec;35(2):190.
PMID: 24362487
Matched MeSH terms: Blood Chemical Analysis/methods*
Fulltext Importance of screening for macroprolactin in all hyperprolactinaemic sera

Jamaluddin FA, Sthaneshwar P, Hussein Z, Othman N, Chan SP

Malays J Pathol, 2013 Jun;35(1):59-63.
PMID: 23817395 MyJurnal

Prolactin (PRL) exists in different forms in human serum. The predominant form is monomeric PRL (molecular mass 23 kDa) with smaller amounts of big PRL (molecular mass 50-60 kDa) and at times macroprolactin (molecular mass 150-170 kDa). Macroprolactin, generally considered to be biologically inactive, accounts for the major part of prolactin in some patients. Different immunoassays for prolactin differ in reactivity with this macromolecular complex.

Matched MeSH terms: Blood Chemical Analysis/methods*
An improved lectin-based method for the detection of mucin-type O-glycans in biological samples

Lee CS, Muthusamy A, Abdul-Rahman PS, Bhavanandan VP, Hashim OH

Analyst, 2013 Jun 21;138(12):3522-9.
PMID: 23665615 DOI: 10.1039/c3an36258b

Mucins and mucin-type glycoproteins, collectively referred to as mucin-type O-glycans, are implicated in many important biological functions and pathological conditions, including malignancy. Presently, there is no reliable method to measure the total mucin-type O-glycans of a sample, which may contain one or more of these macromolecules of unknown structures. We report the development of an improved microassay that is based on the binding of lectins to the unique and constant GalNAc-Ser/Thr structural feature of mucin-type O-glycans. Since the sugar-amino acid linkage in the mucin-type O-glycans is invariably cryptic, we first chemically removed the heterogeneous peripheral and core saccharides of model glycoconjugates before examining for their interactions using an enzyme-linked lectin assay (ELLA). Desialylation of the model glycoconjugates led to maximal binding of the lectins but additional treatments such as Smith degradation did not result in increased binding. Of the lectins tested for their ability to probe the desialylated O-glycans, jacalin showed the highest sensitivity followed by champedak galactose binding (CGB) lectin and Vicia villosa agglutinin. Further improvement in the sensitivity of ELLA was achieved by using microtiter plates that were pre-coated with the CGB lectin, which increased the specificity of the assay to mucin-type O-glycans. Finally, the applicability of the developed sandwich ELLA to crude samples was demonstrated by estimating trace quantities of the mucin-type O-glycans in the human serum.

Matched MeSH terms: Blood Chemical Analysis/methods*
Fulltext Testosterone testing in adult males

Ho CK

Malays J Pathol, 2011 Dec;33(2):71-81.
PMID: 22299206 MyJurnal

The number of requests for testosterone testing in adult males has been increasing in recent years. In this review, the biochemistry and physiology of testosterone in males relevant to the chemical pathologist or clinical biochemist is outlined. The methodology for total testosterone and various laboratory tests associated with the assessment of testosterone status including free testosterone, calculated free testosterone (CFT), bioavailable testosterone (BAT) and free androgen index (FAI) is then summarised. Clinical and laboratory criteria for the diagnosis of late-onset hypogonadism (LOH) in men are critically discussed with particular emphasis on the interpretation of laboratory test results. Finally, other indications for testosterone testing in adult men such as infertility are also reviewed.

Matched MeSH terms: Blood Chemical Analysis/methods*
Fulltext Performance evaluation of the Arkray Adams HA-8160 HbA1c analyser

Thevarajah TM, Nani N, Chew YY

Malays J Pathol, 2008 Dec;30(2):81-6.
PMID: 19291916 MyJurnal

HbA1c measurement is currently routinely used to predict long term outcome of diabetes, thus playing a fundamental role in the management of diabetes. The relationship between HbA1c value and long term diabetic complications has been established by a randomised control Diabetes Control and Complications Trial (DCCT) which used high performance liquid chromatography (HPLC) as a reference method for HbA1c assay. To ensure that HbA1c results from a variety HbA1c assay methods are similar to the DCCT values, the American Diabetes Association (ADA) recommended that all laboratories should use methods certified by the National Glycohemoglobin Standardization Programme (NGSP) with interassay coefficient variation (CV) of < 5% (ideally < 3%). The International Federation of Clinical Chemistry (IFCC) working group on HbA1c standardisation has set a CV < 2.5% as a criteria for its reference laboratories.

Matched MeSH terms: Blood Chemical Analysis/methods
Fulltext An alternate method for DNA and RNA extraction from clotted blood

Zakaria Z, Umi SH, Mokhtar SS, Mokhtar U, Zaiharina MZ, Aziz AT, et al.

Genet. Mol. Res., 2013;12(1):302-11.
PMID: 23408417 DOI: 10.4238/2013.February.4.4

We developed an alternative method to extract DNA and RNA from clotted blood for genomic and molecular investigations. A combination of the TRIzol method and the QIAamp spin column were used to extract RNA from frozen clotted blood. Clotted blood was sonicated and then the QIAamp DNA Blood Mini Kit was used for DNA extraction. Extracted DNA and RNA were adequate for gene expression analysis and copy number variation (CNV) genotyping, respectively. The purity of the extracted RNA and DNA was in the range of 1.8-2.0, determined by absorbance ratios of A(260):A(280). Good DNA and RNA integrity were confirmed using gel electrophoresis and automated electrophoresis. The extracted DNA was suitable for qPCR and microarrays for CNV genotyping, while the extracted RNA was adequate for gene analysis using RT-qPCR.

Matched MeSH terms: Blood Chemical Analysis/methods*
Development and evaluation of electromembrane extraction across a hollow polymer inclusion membrane

Mamat NA, See HH

J Chromatogr A, 2015 Aug 7;1406:34-9.
PMID: 26141273 DOI: 10.1016/j.chroma.2015.06.020

In this work, a new variation of the electromembrane extraction (EME) approach employing a hollow polymer inclusion membrane (HPIM) was developed. In this method, a HPIM was prepared by casting a solution of the desired proportions of cellulose acetate (CTA), tris(2-ethylhexyl)phosphate (TEHP) and di-(2-ethylhexyl)phosphoric acid (D2EHPA) in dichloromethane on glass capillary tubing. Three basic drugs namely amphetamine, methamphetamine, and 3,4-methylenedioxy-N-methylamphetamine (MDMA) were selected as model analytes to evaluate the extraction performance of this new approach. The drugs were extracted from human plasma samples, through a 20μm thickness HPIM, to an aqueous acceptor solution inside the lumen of the hollow membrane. Parameters affecting the extraction efficiency were investigated in detail. Under the optimized conditions, enrichment factors in the range of 97-103-fold were obtained from 3mL of sample solution with a 10min extraction time and an applied voltage of 300V across the HPIM. The detection limits of the method for the three drugs were in the range of 1.0-2.5ng/mL (at a signal/noise ratio of three), with relative standard deviations of between 6.4% and 7.9%. When the method was applied to spiked plasma samples, the relative recoveries ranged from 99.2% to 100.8%. Enrichment factors of 103, 99 and 97 were obtained for amphetamine, methamphetamine, and MDMA, respectively. A comparison was also made between the newly developed approach and EME using supported liquid membranes (SLM) as well as standard sample preparation methods (liquid-liquid extraction) used by the Toxicology Unit, Department of Chemistry, Malaysia.

Matched MeSH terms: Blood Chemical Analysis/methods*
Albumin adjusted calcium: Study in a tertiary care hospital

Mohd Ariffin ZA, Jamaluddin FA

Malays J Pathol, 2020 Dec;42(3):395-400.
PMID: 33361720

INTRODUCTION: One commonly used equation which continues to be widely mentioned in text books and hence familiar to clinical people is total calcium + 0.02 (40 - albumin). This equation was derived using cresophthalein complexone and bromocresol green (BCG) methods for measuring serum total calcium and serum albumin respectively. However this equation maybe invalid when applied to calcium and albumin results generated by alternative assays. Hence we aim to derive an albumin-adjusted calcium equation specific to our laboratory's total calcium and albumin methodologies.
MATERIALS AND METHODS: A total of 3,175 adult University Malaya Medical Centre (UMMC) patients deemed free of any calcium metabolism disorders were selected and divided into two groups for derivation and validation. Simple linear regression associating total calcium and albumin was constructed from the data in the derivation group. The new albumin-adjusted calcium equation was validated in the validation group. Differences in calcium status classification following adjustments based on existing and new albumin-adjusted calcium equation was compared in a 469 hypoalbuminaemic patients.
RESULT: The new albumin adjusted calcium equation was: total calcium + 0.014 x (39-albumin). Of the 469 hypoalbuminemic patients, 78 were classified differently based on new equation. Based on the new equation, 55 normocalcemic patients were classified as hypocalcemic and 22 were classified as normocalcemic instead of hyperclacaemic.
CONCLUSION: Based on the newly derived albuminadjusted calcium equation 17% of patients had different adjusted calcium classifications. This could potentially impact in the management. It is recommended that laboratories derive equations specific to their calcium/albumin methods and analytical platforms.

Matched MeSH terms: Blood Chemical Analysis/methods*
Limitations of calculated ionised calcium & adjusted calcium in critically ill patients: Time to consider measured ionised calcium

Zulkufli NS, Jamaluddin FA, Tengku Yazid TN

Malays J Pathol, 2020 Dec;42(3):385-394.
PMID: 33361719

INTRODUCTION: Ionised calcium is a good prognostic and diagnostic tool as opposed to total calcium in critical patients but is not available in most central laboratories and non-intensive care units. To date, four equations to calculate ionised calcium in critical patients have been published.
OBJECTIVES: (1) Evaluate the four published equations' performance in estimating ionised calcium; (2) Determine the accuracy of calculated ionised and adjusted total calcium in classifying patients according to calcium states; and (3) Identify factors associated with hypocalcaemia in the critically ill population.
MATERIALS AND METHODS: This is a cross-sectional study involving 281 critically ill patients aged 18-80 years of both genders in a Malaysian tertiary intensive care unit. Performance of the four equations was analysed using Bland-Altman difference plot and Passing Bablok regression analysis. Crosstabulation was conducted to assess classification accuracy. Mann-Whitney U or Pearson Chi-Square tests were performed to identify variables associated with hypocalcaemia.
RESULTS: Calculated ionised calcium using all four equations significantly overestimated ionised calcium. Calculated ionised and adjusted total calcium had poor accuracies in classifying hypocalcaemic patients. pH was significantly higher in hypocalcaemics.
CONCLUSION: Calculated ionised and adjusted total calcium significantly overestimate ionised calcium in the critically ill. In this specific population, calcium status should only be confirmed with ionised calcium measured by direct ion-selective electrode (ISE).

Matched MeSH terms: Blood Chemical Analysis/methods*
Rapid quantification of quinine by multi-stacking in a portable microchip electrophoresis system

Tai CT, See HH

Electrophoresis, 2019 02;40(3):455-461.
PMID: 30450561 DOI: 10.1002/elps.201800398

A new multi-stacking pre-concentration procedure based on field-enhanced sample injection (FESI), field-amplified sample stacking, and transient isotachophoresis was developed and implemented in a compact microchip electrophoresis (MCE) with a double T-junction glass chip, coupled with an on-chip capacitively coupled contactless conductivity detection (C4 D) system. A mixture of the cationic target analyte and the terminating electrolyte (TE) from the two sample reservoirs was injected under FESI conditions within the two sample-loading channels. At the double T-junction, the stacked analyte zones were further concentrated under field-amplified stacking conditions and then subsequently focused by transient-isotachophoresis and separated along the separation channels. The proposed multi-stacking strategy was verified under a Universal Serial Bus (USB) fluorescence microscope employing Rhodamine 6G as the model analyte. This developed approach was subsequently used to monitor the target quinine present in human plasma samples. The total analysis time for quinine was approximately 200 s with a sensitivity enhancement factor of approximately 61 when compared to the typical gated injection. The detection and quantification limits of the developed approach for quinine were 3.0 μg/mL and 10 μg/mL, respectively, with intraday and interday repeatability (%RSDs, n = 5) of 3.6 and 4.4%. Recoveries in spiked human plasma were 98.1-99.8%.

Matched MeSH terms: Blood Chemical Analysis/methods
A red-shifted Bioluminescence Resonance Energy Transfer (BRET) biosensing system for rapid measurement of plasmin activity in human plasma

Weihs F, Peh A, Dacres H

Anal Chim Acta, 2020 Mar 15;1102:99-108.
PMID: 32044001 DOI: 10.1016/j.aca.2019.12.044

Proteases are key signalling molecules for many physiological processes and their dysregulation is implicated in the progression of a range of diseases. Sensitive methods to measure protease activities in complex biological samples are critical for rapid disease diagnoses. The proteolytic activity of plasmin reflects the fibrinolysis state of blood and its deregulation can indicate pathologies such as bleeding events. While Bioluminescence Resonance Energy Transfer (BRET) is a powerful and sensitive method for the detection of protease activity, the commonly applied blue-shifted BRET2 system, consisting of the Renilla luciferase Rluc2 and the large-stokes shift fluorescent protein GFP2, suffers from light absorption and light scattering in human plasma samples. To address this challenge, we developed a red-shifted BRET-based plasmin sensor by substituting BRET2 with the BRET6 system. BRET6 is composed of the red-shifted RLuc8.6 luciferase linked to the red light emitting fluorescent protein TurboFP635. The BRET6 biosensor exhibited 3-fold less light absorption in plasma samples compared to the BRET2 sensor leading to an up to a 5-fold increase in sensitivity for plasmin detection in plasma. The limits of detection for plasmin were determined to be 11.90 nM in 7.5% (v/v) plasma with a 10 min assay which enables biologically relevant plasmin activities of thrombolytic therapies to be detected. While a colorigenic plasmin activity assay achieved a similar detection limit of 10.91 nM in 7.5% (v/v) human plasma, it required a 2 h incubation period. The BRET6 sensor described here is faster and more specific than the colorigenic assay as it did not respond to unspiked human plasma samples.

Matched MeSH terms: Blood Chemical Analysis/methods
Fulltext Analytical and diagnostic performance of an automated anti-CCP assay

Pavai S, Sargunan S, Zain AA, Chow SK

Malays J Pathol, 2011 Dec;33(2):101-6.
PMID: 22299210 MyJurnal

Aim: Autoantibodies against cyclic citrullinated peptide (anti-CCP) are considered to be a sensitive and specific marker for rheumatoid arthritis (RA). This study evaluated the diagnostic and analytical performances of the automated anti-CCP assay.
Materials and Method: Sera from 80 patients with established RA, 65 from other rheumatic diseases (non-RA) and 55 from healthy controls were studied using second generation anti-CCP. Rheumatoid factor (RF) was also assayed in each sample, and the results were compared to the anti-CCP fi ndings. Serum pools were used to determine the precision and linearity.
Results: At a cut-off of 7.4 U/ml for anti-CCP, the sensitivity and specificity for RA were 65% and 98% respectively. RF had a sensitivity of 58% and a lower specifi city of 93 % than anti-CCP. Conclusion: The high specificity of the assay suggests that anti-CCP is useful in the diagnosis of rheumatoid arthritis and in our cohort of study population anti-CCP exhibits a better diagnostic value than RF. A considerable proportion (28%) of RF-negative RA patients were anti-CCP positive. Based on analytical performance of the assay, we conclude that full automation and high throughput features of AxSYM makes it an ideal platform for routine testing of anti-CCP.
Study site: Rheumatology clinic, University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia

Matched MeSH terms: Blood Chemical Analysis/methods*
Comparison of serum and plasma for determination of blood biochemical values in Malaysian flying foxes (Pteropus vampyrus)

Heard DJ, Ruiz MM, Harr KE

J. Zoo Wildl. Med., 2006 Sep;37(3):245-8.
PMID: 17319121

The effects of the anticoagulant sodium heparin and time of centrifugation on 20 biochemical analytes in the blood of Malaysian flying foxes (Pteropus vampyrus) were evaluated. Paired plasma and serum samples were centrifuged at 1 hr and 6 hr postcollection. Heparinization and time of centrifugation did not significantly affect albumin, cholesterol, triglycerides, amylase, blood urea nitrogen, creatinine, alanine aminotransferase, aspartate aminotransaminase, alkaline phosphatase, calcium, sodium, and total carbon dioxide levels. Plasma was associated with higher globulin and lower potassium values. Glucose and chloride levels decreased significantly over time, whereas phosphorus levels increased. Serum creatine kinase activity at 6 hr postcollection was significantly higher than the other creatine kinase means. Sodium levels were not significantly affected by sodium heparin as used as an anticoagulant in this study.

Matched MeSH terms: Blood Chemical Analysis/methods

Filters

Please provide feedback to Administrator ([email protected])

External Links