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Depth dependence of the single chamber response function of the I'mRT MatriXX array in a 6 MV photon beam

Alashrah S, Kandaiya S, Lum LS, Cheng SK

Z Med Phys, 2013 Dec;23(4):270-8.
PMID: 24113373 DOI: 10.1016/j.zemedi.2013.09.001

One of the factors which influence the spatial resolution of a 2D detector array is the size of the single detector, another the transport of the secondary electrons from the walls into the measuring volume. In this study, the single ion chamber dose response function of an I'mRT MatriXX array was determined by comparison between slit beam dose profiles measured with the array and with EBT2 radiochromic film in a solid water-equivalent phantom at a shallow depth of 0.5cm and at a depth of 5cm beyond the depth dose maximum for a 6 MV photon beam. The dose response functions were obtained using two methods, the best fit method and the deconvolution method. At the shallow depth, a Lorentz function and at 5cm depth a Gaussian function, both with the same FWHM of 7.4mm within limits of uncertainty, were identified as the best suited dose response functions of the 4.5mm diameter single array chamber. These dose response functions were then tested on various dose profiles whose true shape had been determined with EBT2 film and with the IC03 ionization chamber. By convolving these with the Lorentz kernel (at shallow depth) and the Gaussian kernel (at 5cm depth) the signal profiles measured with the I'mRT MatriXX array were closely approximated. Thus, the convolution of TPS-calculated dose profiles with these dose response functions can minimize the differences between calculation and measurement which occur due to the limited spatial resolution of the I'mRT MatriXX detector.

Matched MeSH terms: Sensitivity and Specificity
The thermoluminescence glow curve and the deconvoluted glow peak characteristics of erbium doped silica fiber exposed to 70-130 kVp x-rays

Alawiah A, Bauk S, Marashdeh MW, Nazura MZ, Abdul-Rashid HA, Yusoff Z, et al.

Appl Radiat Isot, 2015 Oct;104:197-202.
PMID: 26188687 DOI: 10.1016/j.apradiso.2015.07.011

In regard to thermoluminescence (TL) applied to dosimetry, in recent times a number of researchers have explored the role of optical fibers for radiation detection and measurement. Many of the studies have focused on the specific dopant concentration, the type of dopant and the fiber core diameter, all key dependencies in producing significant increase in the sensitivity of such fibers. At doses of less than 1 Gy none of these investigations have addressed the relationship between dose response and TL glow peak behavior of erbium (Er)-doped silica cylindrical fibers (CF). For x-rays obtained at accelerating potentials from 70 to 130 kVp, delivering doses of between 0.1 and 0.7 Gy, present study explores the issue of dose response, special attention being paid to determination of the kinetic parameters and dosimetric peak properties of Er-doped CF. The effect of dose response on the kinetic parameters of the glow peak has been compared against other fiber types, revealing previously misunderstood connections between kinetic parameters and radiation dose. Within the investigated dose range there was an absence of supralinearity of response of the Er-doped silica CF, instead sub-linear response being observed. Detailed examination of glow peak response and kinetic parameters has thus been shown to shed new light of the rarely acknowledged issue of the limitation of TL kinetic model and sub-linear dose response of Er-doped silica CF.

Matched MeSH terms: Sensitivity and Specificity
Semi-quantitative and qualitative assessment of breast ultrasound elastography in differentiating between malignant and benign lesions

Alhabshi SM, Rahmat K, Abdul Halim N, Aziz S, Radhika S, Gan GC, et al.

Ultrasound Med Biol, 2013 Apr;39(4):568-78.
PMID: 23384468 DOI: 10.1016/j.ultrasmedbio.2012.10.016

The purpose of this study was to evaluate the diagnostic value of qualitative and semi-quantitative assessment of ultrasound elastography in differentiating between benign and malignant breast lesions. This prospective study was conducted in two tertiary medical centers. Consecutive B-mode ultrasound and real-time elastographic images were obtained for 67 malignant and 101 benign breast lesions in 168 women. Four experienced radiologists analyzed B-mode ultrasound alone and B-mode ultrasound combined with elastography independently. Conventional ultrasound findings were classified according to the American College of Radiology Breast Imaging Reporting and Data System classification. The elastographic assessment was based on qualitative and semi-quantitative parameters (i.e., strain pattern, width ratio, strain ratio). The sensitivity and specificity of combined elastography and conventional ultrasound were significantly higher than that of conventional ultrasound alone. The sensitivity, specificity, positive predictive value and negative predictive value was 97%, 61.4%, 62.5% and 96.8%, respectively, for conventional ultrasound and 100%, 93%, 99% and 90%, respectively, for combined technique. The semi-quantitative assessment with strain ratio and width ratio in elastography were the most useful parameters in differentiating between benign and malignant breast lesions. Cut-off point values for width ratio of more than 1.1 and strain ratio of more than 5.6 showed a high predictive value of malignancy with specificities of 84% and 76%, respectively (p

Matched MeSH terms: Sensitivity and Specificity
Fulltext Development of swine-specific DNA markers for biosensor-based halal authentication

Ali ME, Hashim U, Kashif M, Mustafa S, Che Man YB, Abd Hamid SB

Genet. Mol. Res., 2012;11(2):1762-72.
PMID: 22843053 DOI: 10.4238/2012.June.29.9

The pig (Sus scrofa) mitochondrial genome was targeted to design short (15-30 nucleotides) DNA markers that would be suitable for biosensor-based hybridization detection of target DNA. Short DNA markers are reported to survive harsh conditions in which longer ones are degraded into smaller fragments. The whole swine mitochondrial-genome was in silico digested with AluI restriction enzyme. Among 66 AluI fragments, five were selected as potential markers because of their convenient lengths, high degree of interspecies polymorphism and intraspecies conservatism. These were confirmed by NCBI blast analysis and ClustalW alignment analysis with 11 different meat-providing animal and fish species. Finally, we integrated a tetramethyl rhodamine-labeled 18-nucleotide AluI fragment into a 3-nm diameter citrate-tannate coated gold nanoparticle to develop a swine-specific hybrid nanobioprobe for the determination of pork adulteration in 2.5-h autoclaved pork-beef binary mixtures. This hybrid probe detected as low as 1% pork in deliberately contaminated autoclaved pork-beef binary mixtures and no cross-species detection was recorded, demonstrating the feasibility of this type of probe for biosensor-based detection of pork adulteration of halal and kosher foods.

Matched MeSH terms: Sensitivity and Specificity
A suitable method to detect potential fraud of bringing Malayan box turtle (Cuora amboinensis) meat into the food chain

Ali ME, Asing, Hamid SB, Razzak MA, Rashid NR, Al Amin M, et al.

Food Addit Contam Part A Chem Anal Control Expo Risk Assess, 2015;32(8):1223-33.
PMID: 26062948 DOI: 10.1080/19440049.2015.1058535

Malayan box turtle (Cuora amboinensis) has been a wildlife-protected vulnerable turtle species in Malaysia since 2005. However, because of its purported usage in traditional medicine, tonic foods and feeds, clandestine black market trade is rampant. Several polymerase chain reaction (PCR) assays for the taxonomic detection and classification of turtle species have been proposed. These assays are based on long-length target amplicons which are assumed to break down under compromised states and, hence, might not be suitable for the forensic tracing and tracking of turtle trafficking. For the first time this paper develops a very short-amplicon-length PCR assay (120 bp) for the detection of Malayan box turtle meat in raw, processed and mixed matrices, and experimental evidence is produced that such an assay is not only more stable and reliable but also more sensitive than those previously published. We checked the assay specificity against 20 different species and no cross-species detection was observed. The possibility of any false-negative detection was eliminated by a universal endogenous control for eukaryotes. The assay detection limit was 0.0001 ng of box turtle DNA from pure meat and 0.01% turtle meat in binary and ternary admixtures and commercial meatballs. Superior target stability and sensitivity under extreme treatments of boiling, autoclaving and microwave cooking suggested that this newly developed assay would be suitable for any forensic and/or archaeological identification of Malayan box turtle species, even in severely degraded specimens. Further, in silico studies indicated that the assay has the potential to be used as a universal probe for the detection of nine Cuora species, all of which are critically endangered.

Matched MeSH terms: Sensitivity and Specificity
Fulltext Screening diabetes using 2HPP urine sugar. [Ujian tapisan diabetes mellitus menggunakan 2HPP gula urin.]

Ali O

Family Physician, 1989;1(1):42-43.

The validity of the 2-hour post-prandial (2HPP) urine glucose was determined among a Malay community in Kuala Selangor. Fifty glycosuric and 80 non-glycosuric samples had their capillary blood glucose and fasting blood sugar tested to determine their diabetic status. It was found that the test was very sensitive but less specific (sensitivity 100% and specificity 72.1%). Samples with 2HPP urine glucose of 3 + had a higher probability of being diabetic than the others.

Matched MeSH terms: Sensitivity and Specificity
Fulltext Diagnostic accuracy of rapid diagnostic tests for the early detection of leptospirosis

Alia SN, Joseph N, Philip N, Azhari NN, Garba B, Masri SN, et al.

J Infect Public Health, 2018 11 27;12(2):263-269.
PMID: 30502041 DOI: 10.1016/j.jiph.2018.10.137

BACKGROUND: Leptospirosis is often misdiagnosed with several other tropical febrile illnesses in Malaysia due to similarities in clinical manifestations. Although treatment regimens could be started based on clinical judgments, early diagnosis has become paramount as a guide to chemotherapeutic interventions. Confirmed laboratory diagnosis through MAT or PCR is time consuming and usually available only in reference laboratories and not practical in healthcare settings. Rapid and easy to perform diagnostic tests are widely used in these settings as the point of care diagnosis. The present study was undertaken to compare the diagnostic performance of two IgM based immunodiagnostic assay kits for acute leptospirosis.
METHODS: A total of 50 serum samples were collected from patients clinically suspected for acute leptospirosis on admission in the Hospital Serdang, from June 2016 to June 2017. All the samples were subjected to MAT, lipL32 PCR and the two rapid tests (Leptocheck-WB and ImmuneMed Leptospira IgM Duo Rapid test).
RESULTS: Out of the 50 clinically suspected patients sampled, 19 were confirmed positive for leptospirosis. Six (12%) were confirmed by MAT and 13 (26%) by PCR. Similarly, of the 50 clinically suspected cases, 17 (34%) showed positivity for Leptocheck-WB and 7 (14%) for ImmuneMed Leptospira IgM Duo Rapid test. The overall sensitivity and specificity was 47.37% and 80.65% for Leptocheck-WB, and 21.05% and 90.32% for ImmuneMed Leptospira IgM Duo Rapid test. In another set of previously confirmed MAT positive samples (1:400-1:3600) obtained from a reference laboratory, Leptocheck-WB showed higher sensitivity (90.72%) than ImmuneMed Leptospira IgM Duo Rapid test (40.21%), and comparable specificity for ImmuneMed Leptospira IgM Duo Rapid test (88.89%) and Leptocheck-WB (82.86%).
CONCLUSION: The sensitivity was higher for Leptocheck-WB and had a comparable specificity with ImmuneMed Leptospira IgM Duo Rapid test. Therefore, based on the present study, Leptocheck-WB is found to be a more sensitive rapid immunodiagnostic test for acute leptospirosis screening in hospital settings.

Matched MeSH terms: Sensitivity and Specificity
Fulltext Evaluation of recombinant antigens for diagnosis of melioidosis

Allwood EM, Logue CA, Hafner GJ, Ketheesan N, Norton RE, Peak IR, et al.

FEMS Immunol. Med. Microbiol., 2008 Oct;54(1):144-53.
PMID: 18657105 DOI: 10.1111/j.1574-695X.2008.00464.x

Burkholderia pseudomallei, the causative agent of melioidosis, is endemic to Southeast Asia and northern Australia. Clinical manifestations of the disease are diverse, ranging from chronic localized infection to acute septicaemia, with death occurring within 24-48 h after the onset of symptoms. Definitive diagnosis of melioidosis involves bacterial culture and identification, with results obtained within 3-4 days. This delayed diagnosis is a major contributing factor to high mortality rates. Rapid diagnosis is vital for successful management of the disease. This study describes the purification and evaluation of three recombinant antigenic proteins, BPSL0972, BipD and OmpA from B. pseudomallei 08, for their potential in the serodiagnosis of melioidosis using an indirect enzyme-linked immunosorbent assay (ELISA) method. The recombinant proteins were evaluated using 74 serum samples from culture-confirmed melioidosis patients from Malaysia, Thailand and Australia. In addition, 62 nonmelioidosis controls consisting of serum samples from clinically suspected melioidosis patients (n=20) and from healthy blood donors from an endemic region (n=18) and a nonendemic region (n=24) were included. The indirect ELISAs using BipD and BPSL0972 as antigens demonstrated poor to moderate sensitivities (42% and 51%, respectively) but good specificity (both 100%). In contrast, the indirect ELISA using OmpA as an antigen achieved 95% sensitivity and 98% specificity. These results highlight the potential for OmpA to be used in the serodiagnosis of melioidosis in an endemic area.

Matched MeSH terms: Sensitivity and Specificity
Multiclass Benchmarking Framework for Automated Acute Leukaemia Detection and Classification Based on BWM and Group-VIKOR

Alsalem MA, Zaidan AA, Zaidan BB, Albahri OS, Alamoodi AH, Albahri AS, et al.

J Med Syst, 2019 Jun 01;43(7):212.
PMID: 31154550 DOI: 10.1007/s10916-019-1338-x

This paper aims to assist the administration departments of medical organisations in making the right decision on selecting a suitable multiclass classification model for acute leukaemia. In this paper, we proposed a framework that will aid these departments in evaluating, benchmarking and ranking available multiclass classification models for the selection of the best one. Medical organisations have continuously faced evaluation and benchmarking challenges in such endeavour, especially when no single model is superior. Moreover, the improper selection of multiclass classification for acute leukaemia model may be costly for medical organisations. For example, when a patient dies, one such organisation will be legally or financially sued for incidents in which the model fails to fulfil its desired outcome. With regard to evaluation and benchmarking, multiclass classification models are challenging processes due to multiple evaluation and conflicting criteria. This study structured a decision matrix (DM) based on the crossover of 2 groups of multi-evaluation criteria and 22 multiclass classification models. The matrix was then evaluated with datasets comprising 72 samples of acute leukaemia, which include 5327 gens. Subsequently, multi-criteria decision-making (MCDM) techniques are used in the benchmarking and ranking of multiclass classification models. The MCDM used techniques that include the integrated BWM and VIKOR. BWM has been applied for the weight calculations of evaluation criteria, whereas VIKOR has been used to benchmark and rank classification models. VIKOR has also been employed in two decision-making contexts: individual and group decision making and internal and external group aggregation. Results showed the following: (1) the integration of BWM and VIKOR is effective at solving the benchmarking/selection problems of multiclass classification models. (2) The ranks of classification models obtained from internal and external VIKOR group decision making were almost the same, and the best multiclass classification model based on the two was 'Bayes. Naive Byes Updateable' and the worst one was 'Trees.LMT'. (3) Among the scores of groups in the objective validation, significant differences were identified, which indicated that the ranking results of internal and external VIKOR group decision making were valid.

Matched MeSH terms: Sensitivity and Specificity
Utility of recombinant LipL41 based IgM and IgG ELISA in diagnosis of canine leptospirosis in an endemic area - a study from Kerala, India

Ambily R, Mini M, Siju J, Vamshikrishna S, Abhinay G, Gleeja VL, et al.

Trop Biomed, 2019 Sep 01;36(3):654-663.
PMID: 33597487

A study was undertaken to evaluate the relevance of detecting IgM and IgG antibodies in diagnosis of canine leptospirosis in Kerala, a southern state of India, which is endemic for the disease. A total of 205 blood (35 from healthy vaccinated, 30 from healthy unvaccinated and 140 from diseased dogs) and 151 urine samples (11 from healthy vaccinated and 140 from diseased dogs) were collected from three districts of Kerala, Thrissur, Palakkad and Kozhikode with high incidence of leptospirosis. Recombinant LipL41 protein was used as antigen and IgG and IgM based ELISAs were standardized. The results were compared with the gold standard test, microscopic agglutination test (MAT). The MAT positive samples (146 samples) were divided into those having titre >1:800 and those between 1:100 and 1:400 in view that the former constituted the acute cases. It was found that IgM ELISA was more specific and sensitive in detecting acute cases (MAT >1:800) whereas IgG ELISA was less specific. In case of seroprevalence studies (MAT titre 1:100 to 1: 400), IgG ELISA was found to be more sensitive and specific than IgM ELISA. Receiver operating characteristic curves when plotted, revealed the accuracy of IgM ELISA in acute leptospirosis. Many samples were positive for both IgG and IgM antibodies. Polymerase Chain Reaction (PCR) targeting lipl41 gene was standardized and urine and blood samples from the same dogs were tested. PCR was found to be the specific test for the early detection of leptospires in blood even before seroconversion. However, PCR analysis of the urine samples was found to be insensitive. Hence, it can be concluded that the diagnostic strategies should be modified, and a combination of serological and molecular tests is recommended in endemic areas rather than simple detection of IgM or IgG antibodies, for the early detection of acute clinical cases of leptospirosis.

Matched MeSH terms: Sensitivity and Specificity
Fulltext Identification and real-time expression analysis of selected Toxoplasma gondii in-vivo induced antigens recognized by IgG and IgM in sera of acute toxoplasmosis patients

Amerizadeh A, Khoo BY, Teh AY, Golkar M, Abdul Karim IZ, Osman S, et al.

BMC Infect Dis, 2013;13:287.
PMID: 23800344 DOI: 10.1186/1471-2334-13-287

Toxoplasma gondii is an obligate intracellular zoonotic parasite of the phylum Apicomplexa which infects a wide range of warm-blooded animals, including humans. In this study in-vivo induced antigens of this parasite was investigated using in-vivo induced antigen technology (IVIAT) and pooled sera from patients with serological evidence of acute infection.

Matched MeSH terms: Sensitivity and Specificity
Metabolomics profiling and pathway analysis of human plasma and urine reveal further insights into the multifactorial nature of coronary artery disease

Amin AM, Mostafa H, Arif NH, Abdul Kader MAS, Kah Hay Y

Clin Chim Acta, 2019 Jun;493:112-122.
PMID: 30826371 DOI: 10.1016/j.cca.2019.02.030

BACKGROUND: Coronary artery disease (CAD) claims lives yearly. Nuclear magnetic resonance (1H NMR) metabolomics analysis is efficient in identifying metabolic biomarkers which lend credence to diagnosis. We aimed to identify CAD metabotypes and its implicated pathways using 1H NMR analysis.
METHODS: We analysed plasma and urine samples of 50 stable CAD patients and 50 healthy controls using 1H NMR. Orthogonal partial least square discriminant analysis (OPLS-DA) followed by multivariate logistic regression (MVLR) models were developed to indicate the discriminating metabotypes. Metabolic pathway analysis was performed to identify the implicated pathways.
RESULTS: Both plasma and urine OPLS-DA models had specificity, sensitivity and accuracy of 100%, 96% and 98%, respectively. Plasma MVLR model had specificity, sensitivity, accuracy and AUROC of 92%, 86%, 89% and 0.96, respectively. The MVLR model of urine had specificity, sensitivity, accuracy and AUROC of 90%, 80%, 85% and 0.92, respectively. 35 and 12 metabolites were identified in plasma and urine metabotypes, respectively. Metabolic pathway analysis revealed that urea cycle, aminoacyl-tRNA biosynthesis and synthesis and degradation of ketone bodies pathways were significantly disturbed in plasma, while methylhistidine metabolism and galactose metabolism pathways were significantly disturbed in urine. The enrichment over representation analysis against SNPs-associated-metabolite sets library revealed that 85 SNPs were significantly enriched in plasma metabotype.
CONCLUSIONS: Cardiometabolic diseases, dysbiotic gut-microbiota and genetic variabilities are largely implicated in the pathogenesis of CAD.

Matched MeSH terms: Sensitivity and Specificity
Fulltext Diagnostic tools in childhood malaria

Amir A, Cheong FW, De Silva JR, Lau YL

Parasit Vectors, 2018 01 23;11(1):53.
PMID: 29361963 DOI: 10.1186/s13071-018-2617-y

Every year, millions of people are burdened with malaria. An estimated 429,000 casualties were reported in 2015, with the majority made up of children under five years old. Early and accurate diagnosis of malaria is of paramount importance to ensure appropriate administration of treatment. This minimizes the risk of parasite resistance development, reduces drug wastage and unnecessary adverse reaction to antimalarial drugs. Malaria diagnostic tools have expanded beyond the conventional microscopic examination of Giemsa-stained blood films. Contemporary and innovative techniques have emerged, mainly the rapid diagnostic tests (RDT) and other molecular diagnostic methods such as PCR, qPCR and loop-mediated isothermal amplification (LAMP). Even microscopic diagnosis has gone through a paradigm shift with the development of new techniques such as the quantitative buffy coat (QBC) method and the Partec rapid malaria test. This review explores the different diagnostic tools available for childhood malaria, each with their characteristic strengths and limitations. These tools play an important role in making an accurate malaria diagnosis to ensure that the use of anti-malaria are rationalized and that presumptive diagnosis would only be a thing of the past.

Matched MeSH terms: Sensitivity and Specificity
Fulltext Evaluation of a Commercial Immuno-Chromatographic Assay Kit for Rapid Detection of IgM Antibodies against Leptospira Antigen in Human Serum

Amran F, Liow YL, Halim NAN

J Korean Med Sci, 2018 Apr 23;33(17):e131.
PMID: 29686599 DOI: 10.3346/jkms.2018.33.e131

Leptospirosis is a febrile zoonotic disease. Routine diagnosis of leptospirosis is based on the detection of specific antibodies with serological tests. The aim of our study was to determine the usefulness of immunochromatographic assay (ICA), ImmuneMed Leptospira IgM Duo Rapid test kit from Korea, in rapid screening of acute leptospirosis in emergency cases with limited expertise. A total of 197 serum samples (93 positive, 104 negative) were selected randomly. The test has good diagnostic sensitivity 73% and specificity 90%. With positive predictive value of 87% and negative predictive value of 79%, this reassures patients have higher chance of correct diagnosis. This ICA is acceptable for screening of leptospirosis but confirmation with microscopic agglutination test should follow.

Matched MeSH terms: Sensitivity and Specificity
Fulltext A New Diagnostic Approach in the Detection of Breast Carcinoma: Electrical Impedance Measurement with TransScan TS 2000

Amran, A.R., Fatimah, M.

International Medical Journal Malaysia, 2007;6(2):1-11.
MyJurnal

Introduction: Mammography is commonly regarded as the single most important tool for screening and for early detection of breast cancer. However it is not generally recommended for women under 40 years of age and in those taking hormone replacement therapy as the increased density of the breast parenchyma may make mammography more difficult to read and interpret. The limitations of mammography have spurred attempts to find new techniques that can be used either separately or in conjunction with mammography. Purpose: The aim of this study was to quantify the clinical value of using electrical impedance scanning (EIS) or Trans Scan as an adjunct to mammography in order to identify cancerous tissue based upon its inherent altered local dielectric properties. Methods and Materials: The patients were examined using Trans Scan (Trans Scan Medical, Ltd., distributed by Siemens AG. The study population was derived from patients with suspicious breast lesions categorized as BIRADS 3 or 4 detected during mammography or ultrasound. Results: Fifty-three women with 53 mammographically and/or sonographically suspicious findings were examined using EIS. With respect to the histopathological findings (15 malignant and 38 benign lesions) 13 of 15 (86.6% sensitivity) malignant lesions were correctly identified using EIS whereas, 33 of 38 (81.5% specificity) benign lesions were correctly identified. Negative and positive predictive values of 93.9% and 65% were observed respectively. Two benign lesions were correctly identified in a dense breast. The smallest lesion detected in this study measured 20 x 14 mm, which was an infiltrating ductal carcinoma. Conclusion: Electrical impedance scanning as an adjunct to mammography or ultrasound in classifying suspicious lesions is promising because it increases the sensitivity for cancer detection and may reduce biopsy of equivocal lesions. The additional use of EIS with negative predictive value of 93.9% may be useful to exclude some benign lesions from further diagnostic or invasive procedures. Artifacts, such as signals from superficial skin lesions, poor contact and bubbles are currently a limitation

Matched MeSH terms: Sensitivity and Specificity
Natural radioactivity in Algerian building materials

Amrani D, Tahtat M

Appl Radiat Isot, 2001 Apr;54(4):687-9.
PMID: 11225705

Samples of natural and manufactured building materials collected from Algiers have been analysed for 226Ra, 232Th and 40K using a high-resolution HPGe gamma-spectrometry system. The specific concentrations for 226Ra, 232Th and 40K, from the selected building materials, ranged from (12-65 Bq kg(-1)), (7-51 B qkg(-1)) and (36-675 Bq kg(-1)), respectively. The measured activity concentrations for these natural radionuclides were compared with the reported data of other countries and with the world average activity of soil. Radium-equivalent activities were calculated for the measured samples to assess the radiation hazards arising from using those materials in the construction of dwellings. All building materials showed Ra(eq) activities lower than the limit set in the OECD report (370 Bq kg(-1)), equivalent to external gamma-dose of 1.5 mSv yr(-1).

Matched MeSH terms: Sensitivity and Specificity
Ambient temperature detection of PCR amplicons with a novel sequence-specific nucleic acid lateral flow biosensor

Ang GY, Yu CY, Yean CY

Biosens Bioelectron, 2012 Oct-Dec;38(1):151-6.
PMID: 22705404 DOI: 10.1016/j.bios.2012.05.019

In the field of diagnostics, molecular amplification targeting unique genetic signature sequences has been widely used for rapid identification of infectious agents, which significantly aids physicians in determining the choice of treatment as well as providing important epidemiological data for surveillance and disease control assessment. We report the development of a rapid nucleic acid lateral flow biosensor (NALFB) in a dry-reagent strip format for the sequence-specific detection of single-stranded polymerase chain reaction (PCR) amplicons at ambient temperature (22-25°C). The NALFB was developed in combination with a linear-after-the-exponential PCR assay and the applicability of this biosensor was demonstrated through detection of the cholera toxin gene from diarrheal-causing toxigenic Vibrio cholerae. Amplification using the advanced asymmetric PCR boosts the production of fluorescein-labeled single-stranded amplicons, allowing capture probes immobilized on the NALFB to hybridize specifically with complementary targets in situ on the strip. Subsequent visual formation of red lines is achieved through the binding of conjugated gold nanoparticles to the fluorescein label of the captured amplicons. The visual detection limit observed with synthetic target DNA was 0.3 ng and 1 pg with pure genomic DNA. Evaluation of the NALFB with 164 strains of V. cholerae and non-V. cholerae bacteria recorded 100% for both sensitivity and specificity. The whole procedure of the low-cost NALFB, which is performed at ambient temperature, eliminates the need for preheated buffers or additional equipment, greatly simplifying the protocol for sequence-specific PCR amplicon analysis.

Matched MeSH terms: Sensitivity and Specificity
Diagnostic value of electrocardiogram in cardiac tamponade

Ang KP, Nordin RB, Lee SCY, Lee CY, Lu HT

Med J Malaysia, 2019 02;74(1):51-56.
PMID: 30846663

INTRODUCTION: We aim to study the diagnostic value of electrocardiogram (ECG) in cardiac tamponade.
METHODS: This study was a single centre, retrospective casecontrol study. We recruited 42 patients diagnosed with cardiac tamponade of various aetiologies confirmed by transthoracic echocardiography and 100 controls between January 2011 and December 2015. The ECG criteria of cardiac tamponade we adopted was as follows: 1) Low QRS voltage in a) the limb leads alone, b) in the precordial leads alone or, c) in all leads, 2) PR segment depression, 3) Electrical alternans, and 4) Sinus tachycardia.
RESULTS: Malignancy was the most common causes of cardiac tamponade, the two groups were of similar proportion of gender and ethnicity. We calculated the sensitivity (SN), specificity (SP), positive predictive value (PPV), and negative predictive value (NPV) of each ECG criteria. Among the ECG abnormalities, we noted the SN of 'low voltage in all chest leads' (69%), 'low voltage in all limb leads' (67%) and 'sinus tachycardia' (69%) were higher as compared to 'PR depression' (12%) and 'electrical alternan' (5%). On the other hand, 'low voltage in all chest leads' (98%), 'low voltage in all leads' (99%), 'PR depression' (100%) and 'electrical alternans' (100%) has highest SP.
CONCLUSION: Our study reaffirmed the findings of previous studies that electrocardiography cannot be used as a screening tool for diagnosing cardiac tamponade due to its low sensitivity. However, with clinical correlation, electrocardiography is a valuable adjuvant test to 'rule in' cardiac tamponade because of its high specificity.

Matched MeSH terms: Sensitivity and Specificity
Comparison of the third molar maturity index (I3M) between left and right lower third molars to assess the age of majority: a multi-ethnic study sample

Angelakopoulos N, Galić I, Balla SB, Kiş HC, Gómez Jiménez L, Zolotenkova G, et al.

Int J Legal Med, 2021 Nov;135(6):2423-2436.
PMID: 34228192 DOI: 10.1007/s00414-021-02656-2

The diagnostic accuracy of the I3M to assess the legal age of 18 years has already been tested in several specific-population samples. The left lower third molar has been extensively used for discriminating between minors and adults. This research aimed to compare the usefulness of lower third molar maturity indexes, from both left and right side (I3ML and I3MR), in samples originating from four distinct continents in order to examine possible differences in their accuracy values. For this purpose, a sample of 10,181 orthopantomograms (OPGs), from Europe, Africa, Asia and America, was analysed and previously scored in other studies. The samples included healthy subjects with no systemic disorders with both third molars and clear depicted root apices. Wilcoxon Signed Rank test for left and right asymmetry did not show any significant differences. Data about sensitivity, specificity, predictive values, likelihood ratio and accuracy were pooled together and showed similar results for I3ML and I3MR, respectively. In addition, all these quantities were high when only the I3MR was considered to discriminate between adults and minors. The present referable database was the first to pool third molar measurements using panoramic radiographs of subjects coming from different continents. The results highlighted that both I3ML and I3MR are reliable indicators for assessing the legal age of 18 years old in those jurisdictions where this legal threshold has been set as the age of majority.

Matched MeSH terms: Sensitivity and Specificity
Fulltext Comparison of two nested PCR methods for the detection of human malaria

Anthony C, Mahmud R, Lau YL, Syedomar SF, Sri La Sri Ponnampalavanar S

Trop Biomed, 2013 Sep;30(3):459-66.
PMID: 24189676 MyJurnal

Battling malaria will be a persistent struggle without the proper means to diagnose the parasitic infection. However, the inherent limitations of microscopy, the conventional method of diagnosing malaria, affect the accuracy of diagnosis. The present study aimed to compare the accuracy of two different set of primers targeting the small subunit ribosomal RNA (ssRNA) and the dihydrofolate reductase-thymidylate synthase linker region (dhfr-ts) in detecting species specific malaria infections by nested PCR. The sensitivity and specificity of nested PCR assay using the two primers were calculated with reference to microscopy as the 'gold standard'. The results show that 18S rRNA primers had 91.9% sensitivity and 100% specificity in detecting human Plasmodium species as opposed to dhfr-ts primers which had 51.4% sensitivity and 100% specificity. The higher sensitivity of 18S rRNA primers suggests that it may be a better diagnostic tool for detecting human malaria.

Matched MeSH terms: Sensitivity and Specificity

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