Development of a laboratory analytical method beneficial to the policies of the Canada-wide standards for dioxins and furans

Equivalency Factors ◽

Soils And Sediments ◽

Toxic Equivalents ◽

An enzyme-linked immunosorbent assay (ELISA) was tested for its ability to screen for PCDD/F in soils and sediments at 50, 1000 and 10,000 picograms toxic equivalents per gram of soil pgTEQ g-₁ (n=48, r²=0.994, slope=0.94). These results relied on two concepts developed in this thesis. The first, a congener correction factor, corrects ELISA results for differences in how ELISA and GC-HRMS calculate the dioxin content of a sample. The congener correction factor increased the correlation between ELISA and GC-HRMS TEQ values calculated using World Health Organization (WHO) toxic equivalency factors (TEF) from 83% to 94%. The correlation between ELISA and GC-HRMS TEQ values calculated using North Atlantic Treaty Organization (NATO) TEF remained strong when the correction factor was applied, falling from 102% to 94%. The second concept, a sample algorithm allows ELIAS to efficiently measure unknown PCDD/F concentrations between 30 and 10,5000 pgTEQ g-¹. The algorithm successfully placed 24 of 28 samples into their correct concentration ranges in a maximum of two ELISA each. A cost analysis of using the algorithm predicted that ELISA can screen samples three times faster than GC-HRMS while at a 60% reduction in operating cost. The success of ELISA in conjunction with its time and cost savings indicate that it can replace GC-HRMS in situations where the high precision of GC-HRMS is not required.

Development of a laboratory analytical method beneficial to the policies of the Canada-wide standards for dioxins and furans

10.32920/ryerson.14652477 ◽

2021 ◽

Author(s):

Eric Paul Buan

Keyword(s):

Correction Factor ◽

Operating Cost ◽

Cost Savings ◽

World Health ◽

Equivalency Factors ◽

Soils And Sediments ◽

Toxic Equivalents ◽

The 2005 World Health Organization Reevaluation of Human and Mammalian Toxic Equivalency Factors for Dioxins and Dioxin-Like Compounds

Toxicological Sciences ◽

10.1093/toxsci/kfl055 ◽

2006 ◽

Vol 93 (2) ◽

pp. 223-241 ◽

Cited By ~ 2325

Author(s):

Martin Van den Berg ◽

Linda S. Birnbaum ◽

Michael Denison ◽

Mike De Vito ◽

William Farland ◽

...

Keyword(s):

World Health Organization ◽

World Health ◽

Equivalency Factors ◽

Advances in Diagnostic Methods for Zika Virus Infection

Journal of Medical Devices ◽

10.1115/1.4041086 ◽

2018 ◽

Vol 12 (4) ◽

Cited By ~ 11

Author(s):

Carlos A. Herrada ◽

Md. Alamgir Kabir ◽

Rommel Altamirano ◽

Waseem Asghar

Keyword(s):

Reverse Transcription ◽

Zika Virus ◽

Vaccine Development ◽

Genome Structure ◽

Diagnostic Methods ◽

World Health ◽

Health Concern ◽

Localized Surface Plasmon ◽

The Zika virus (ZIKV) is one of the most infamous mosquito-borne flavivirus on recent memory due to its potential association with high mortality rates in fetuses, microcephaly and neurological impairments in neonates, and autoimmune disorders. The severity of the disease, as well as its fast spread over several continents, has urged the World Health Organization (WHO) to declare ZIKV a global health concern. In consequence, over the past couple of years, there has been a significant effort for the development of ZIKV diagnostic methods, vaccine development, and prevention strategies. This review focuses on the most recent aspects of ZIKV research which includes the outbreaks, genome structure, multiplication and propagation of the virus, and more importantly, the development of serological and molecular detection tools such as Zika IgM antibody capture enzyme-linked immunosorbent assay (Zika MAC-ELISA), plaque reduction neutralization test (PRNT), reverse transcription quantitative real-time polymerase chain reaction (qRT-PCR), reverse transcription-loop mediated isothermal amplification (RT-LAMP), localized surface plasmon resonance (LSPR) biosensors, nucleic acid sequence-based amplification (NASBA), and recombinase polymerase amplification (RPA). Additionally, we discuss the limitations of currently available diagnostic methods, the potential of newly developed sensing technologies, and also provide insight into future areas of research.

Exposure to mixtures and congeners of polychlorinated biphenyls

Clinical Chemistry ◽

10.1093/clinchem/40.7.1409 ◽

1994 ◽

Vol 40 (7) ◽

pp. 1409-1415 ◽

Cited By ~ 7

Author(s):

S Skerfving ◽

B G Svensson ◽

L Asplund ◽

L Hagmar

Keyword(s):

Polychlorinated Biphenyls ◽

Biological Samples ◽

Total Pcbs ◽

Limited Information ◽

Biomarkers Of Exposure ◽

Equivalency Factors ◽

Specific Analysis ◽

Toxic Equivalents ◽

The Relationship

Abstract There are 209 congeners of polychlorinated biphenyls (PCBs), the metabolism and toxicity of which vary by congeners. Use of PCBs is now restricted, but environmental contamination and human exposure persist. Analysis for "total PCBs" in biological samples gives limited information; congener-specific analysis is far more informative, but more complicated. Concentrations of congeners in serum/plasma, adipose tissue, or milk are useful biomarkers of exposure. Lipids may contain similar concentrations and congener patterns, but these vary between exposures and are different from those of the corresponding exposure mixtures; hence, analysis of lipids cannot be used to identify the original exposure. Some non- and mono-ortho congeners may attain a coplanar conformation, which renders them capable of a dioxin-like action. Toxic equivalency factors (TEFs) have been used to sum that risk as toxic equivalents (TEQs), which are considerably different from congener concentrations. No reliable data have been developed on the relationship between concentrations of "total PCBs" or congeners in biological samples and effects of PCBs on human health, mainly because of the various analytical procedures involved and confounding exposures.

Development and Analytical Validation of an Immunoassay for Quantifying Serum Anti-Pertussis Toxin Antibodies Resulting from Bordetella pertussis Infection

Clinical and Vaccine Immunology ◽

10.1128/cvi.00248-09 ◽

2009 ◽

Vol 16 (12) ◽

pp. 1781-1788 ◽

Cited By ~ 26

Author(s):

Sandra L. Menzies ◽

Vijay Kadwad ◽

Lucia C. Pawloski ◽

Tsai-Lien Lin ◽

Andrew L. Baughman ◽

...

Keyword(s):

Pertussis Toxin ◽

Bordetella Pertussis ◽

Collaborative Study ◽

World Health ◽

Analytical Validation ◽

Igg Antibody ◽

Pertussis Infection ◽

Validation Parameters ◽

ABSTRACT Adequately sensitive and specific methods to diagnose pertussis in adolescents and adults are not widely available. Currently, no Food and Drug Administration-approved diagnostic assays are available for the serodiagnosis of Bordetella pertussis. Since concentrations of B. pertussis-specific antibodies tend to be high during the later phases of disease, a simple, rapid, easily transferable serodiagnostic test was developed. This article describes test development, initial evaluation of a prototype kit enzyme-linked immunosorbent assay (ELISA) in an interlaboratory collaborative study, and analytical validation. The data presented here demonstrate that the kit met all prespecified criteria for precision, linearity, and accuracy for samples with anti-pertussis toxin (PT) immunoglobulin G (IgG) antibody concentrations in the range of 50 to 150 ELISA units (EU)/ml, the range believed to be most relevant for serodiagnosis. The assay met the precision and linearity criteria for a wider range, namely, from 50 to 200 EU/ml; however, the accuracy criterion was not met at 200 EU/ml. When the newly adopted World Health Organization International Standard for pertussis antiserum (human) reference reagent was used to evaluate accuracy, the accuracy criteria were met from 50 to 200 international units/ml. In conclusion, the IgG anti-PT ELISA met all assay validation parameters within the range considered most relevant for serodiagnosis. This ELISA was developed and analytically validated as a user-friendly kit that can be used in both qualitative and quantitative formats. The technology for producing the kit is transferable to public health laboratories.

Comparison of Western Immunobloting to an Enzyme-Linked Immunosorbent Assay for the Determination of Anti-Bordetella pertussis Antibodies

Clinical and Vaccine Immunology ◽

10.1128/cvi.00450-10 ◽

2011 ◽

Vol 18 (4) ◽

pp. 615-620 ◽

Cited By ~ 1

Author(s):

Stephen D. Merrigan ◽

Ryan J. Welch ◽

Christine M. Litwin

Keyword(s):

Immunosorbent Assay ◽

Bordetella Pertussis ◽

World Health ◽

Recent Infection ◽

Content Type ◽

Igm Elisa ◽

Iga Antibodies ◽

ABSTRACTDuringBordetella pertussisinfection, it has been established that an increase of anti-pertussis toxin (PT) and anti-filamentous hemagglutinin (FHA) antibodies occurs. Immunoblots from two manufacturers using FHA and PT antigens were compared with an enzyme-linked immunosorbent assay (ELISA) that used both FHA and PT. One manufacturer used two concentrations of PT bands for the IgG immunoblot, calibrated to the World Health Organization standard for PT in international units (IU/ml), 100 IU/ml (PT-100) and 8 IU/ml (PT). The second immunoblot kit measured antibodies to a single calibrated PT band. Both kits measured IgA antibodies, and one additionally measured IgM antibodies. Two of 41 (5%) ELISA IgM positives were confirmed positive by IgM immunoblotting, suggesting poor specificity of the IgM ELISA. The agreements of the IgG and IgA immunoblots with the ELISA ranged from 72.5% to 85.3%, with only 38 to 51% of IgA positives confirmed by immunoblotting and only 61 to 68% of IgG positives confirmed by immunoblotting. The two immunoblots correlated well with each other, with 91.7% and 94.3% agreement for IgG and IgA, respectively. When the FHA band was used with the PT band as the criterion for positivity, significant differences existed in specificity compared to the ELISA (IgG, 84.1% versus 33.3%; IgA, 82.4% versus 71.0%). When the positive IgA immunoblots (evidence of natural recent infection) were compared to the positive PT-100 IgG immunoblots (evidence of recent infection or vaccination), the PT-100 blot showed a 71% sensitivity in detecting natural recent infection.B. pertussisimmunoblots, alone or in combination with ELISAs, can aid in the diagnosis ofB. pertussisinfection.

CD4 Variability in Malawi: Implications for Use of a CD4 Threshold of 500 Cells/mm3 Versus Universal Eligibility for Antiretroviral Therapy

Open Forum Infectious Diseases ◽

10.1093/ofid/ofw180 ◽

2016 ◽

Vol 3 (3) ◽

Cited By ~ 1

Author(s):

Alan L. Schooley ◽

Pocha Samuel Kamudumuli ◽

Sitaram Vangala ◽

Chi-hong Tseng ◽

Chifundo Soko ◽

...

Keyword(s):

Antiretroviral Therapy ◽

Geometric Mean ◽

Cost Savings ◽

Cd4 Count ◽

World Health ◽

Misclassification Rate ◽

Cd4 Counts ◽

Cell Counts ◽

Misclassification Rates ◽

Abstract Background. Given the uncertainty about the ability of a single CD4 count to accurately classify a patient as antiretroviral therapy (ART) eligible, we sought to understand the extent to which CD4 variability results in misclassification at a CD4 threshold of 500 cells/mm3. Methods. We performed a prospective study of CD4 variability in Malawian human immunodeficiency virus-infected, ART-naive, World Health Organization (WHO) stage 1 or 2, nonpregnant adults. CD4 counts were performed daily for 8 days. We fit a Bayesian linear mixed-effects model of log-transformed CD4 cell counts to the data. We used Monte Carlo approximations to estimate misclassification rates for different observed values of CD4. The misclassification rate was calculated based on the conditional probability of true CD4 given the geometric mean of observed CD4 measurements. Results. Fifty patients were enrolled from 2 sites. The median age was 33.5 years (interquartile range, 27.5–40.0) and 34 (68%) were female. Misclassification rates were <1% when the observed CD4 counts were ≤250 or ≥750 cells/mm3. Rates of misclassification were high at observed CD4 counts between 350 and 650 cells/mm3, particularly when a single measurement was used (up to 46.7%). Conclusions. Our data show that ART eligibility based on a single CD4 count results in highest risk of misclassification when observed CD4 counts are in the range of 350–650 cells/mm3. Given the benefits of early ART, countries should weigh the costs and complexity of CD4 testing using a 500 cell/mm3 threshold against the cost savings and public health benefits of universal eligibility.

Characteristics, distribution and sources of polychlorinated biphenyls (PCBs) in coastal sediments from the heavily industrialized area of Asalouyeh, Iran

Water Science & Technology ◽

10.2166/wst.2017.500 ◽

2017 ◽

Vol 76 (12) ◽

pp. 3340-3350 ◽

Cited By ~ 20

Author(s):

Hossein Arfaeinia ◽

Zahra Asadgol ◽

Ehsan Ahmadi ◽

Morteza Seifi ◽

Masoud Moradi ◽

...

Keyword(s):

Polychlorinated Biphenyls ◽

Persian Gulf ◽

Dry Weight ◽

Coastal Sediments ◽

World Health ◽

Multivariate Statistical ◽

Contamination Levels ◽

Toxic Equivalents ◽

The Persian Gulf ◽

Abstract In this research, the levels of polychlorinated biphenyls (PCBs) were investigated in the marine sediments of Asaluyeh harbor, in the Persian Gulf. The samples were taken from industrial, semi-industrial and urban regions. The mean concentration levels of total (Σ) 18 detected PCBs were 514.32, 144.67 and 31.6 pg/g dw for the industrial, semi-industrial and urban sampling stations, respectively. Based on a multivariate statistical analysis, it was found that high contamination levels of PCBs in sediments collected along the Persian Gulf were associated with releases from local industries. Total organic carbon (TOC) content was significantly and positively correlated with the concentrations of PCB congeners. World Health Organization toxic equivalents (TEQs) for PCBs ranged from 0.04 to 2.66 pg TEQ/g dry weight (dw) in the coastal sediments. The TEQ values in this study were higher than many reported worldwide in the literature for sediments. This suggests that there are high levels of contamination in the area due to industrial and other human activities.

Migration in times of pandemic: SARS-CoV-2 infection among the Warao indigenous refugees in Belém, Pará, Amazonia, Brazil

BMC Public Health ◽

10.1186/s12889-021-11696-7 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Hilton Pereira da Silva ◽

Isabella Nogueira Abreu ◽

Carlos Neandro Cordeiro Lima ◽

Aline Cecy Rocha de Lima ◽

Alexandre do Nascimento Barbosa ◽

...

Keyword(s):

World Health ◽

Epidemiological Surveillance ◽

Vulnerable Groups ◽

Igg Antibodies ◽

High Exposure ◽

Unified Health System ◽

Private And Public ◽

Health Organization ◽

The City

Abstract Background The emergence of the new causative agent of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in the city of Wuhan, China, in December 2019, and its spread worldwide, led the World Health Organization (WHO) to declare a pandemic. The disease has caused high mortality among traditional populations and the most socially vulnerable groups such indigenous and refugees. The present study aims to investigate the prevalence of anti-SARS-CoV-2 IgG antibodies in the population of Venezuelan indigenous Warao refugees residing in private and public shelters in the city of Belem, capital of Para State, in the Brazilian Amazon. Methods One hundred one individuals of both sexes (43 men and 58 women) with ages varying from 18 to 77 years (average of 36 years) were investigated. Whole blood samples were collected and subsequently separated into plasma and leukocytes. Serological analysis was performed using an enzyme-linked immunosorbent assay - ELISA (Anti-SARS-COV-2 S1 IgG, EUROIMMUN, USA). Results The results indicate a positive serum prevalence of 83.2% (84), of which 77.6% (45/58) were females and 90.7% (39/43) were males. An indeterminate profile was observed in 6.9% (7), where it was not possible to confirm the presence of antibodies, and 9.9% (10) individuals were negative for IgG antibodies. Conclusions The finding of the high seroprevalence of IgG anti-SARS-CoV-2 antibodies reveals a high exposure of the Warao population in Belem to infection with the new coronavirus. These results underscore the importance of maintaining epidemiological surveillance with testing in traditional populations due to the high possibility of spreading the virus, especially among the most socioeconomically vulnerable groups, which depend exclusively on the Unified Health System (SUS), such as refugees and indigenous people.

Overview of coronavirus - Understanding origin, pathogenesis, clinical features & diagnostic approach to COVID-19 in Indian scenario

10.17727/jmsr.2020/8s1-5 ◽

2020 ◽

Vol 8 (S1) ◽

pp. 41-52

Author(s):

Bilolikar AK ◽

Reddy SG ◽

Banerjee J ◽

Fatima R ◽

Poonam AR

Keyword(s):

Clinical Features ◽

Close Contact ◽

Risk Groups ◽

Laboratory Diagnosis ◽

World Health ◽

Alveolar Type ◽

Protein Receptor ◽

Novel Coronavirus ◽

In early December 2019, an outbreak of novel coronavirus (2019-nCoV) or the severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) as it is now called, occurred in Wuhan City, Hubei Province, China. On January 30, 2020 the World Health Organization declared the outbreak as a Public Health Emergency of International Concern. Vaccines to prevent human coronavirus infections are not yet available. Coronavirus disease 2019 (COVID-19) spreads primarily when people are in close contact with small droplets produced by an infected person, identified as “super spreaders”. COVID-19 can be fatal among high-risk groups patients >60 yr. The envelope spike “S” protein receptor binding domain of SARS-CoV-2 use host receptor angiotensin-converting enzyme 2 (ACE2) to enter the cells of airway epithelium and alveolar type 2 (AT2) pneumocytes, and pulmonary cells. The most common clinical features are fever (80-90%), cough (60-80%) and breathlessness (18-46%). The other symptoms include myalgia, sore throat, loss of taste and smell, headache, nausea, vomiting and diarrhoea. Infection control practices to be followed stringently by Health Care Workers (HCW). Standard precautions to be maintained. Specimen to be packed in triple container packing. Cold temperature to be maintained during transport and storage. Laboratory tests of COVID-19 are broadly categorized into two methods: (1) Nucleic acid based assay: RT-PCR, TrueNAT, CBNAAT & (2) Immunoassay: Can be broadly divided into 2 types: Antigen based assay: Rapid antigen test, Antibody based assay: enzyme-linked immunosorbent assay (ELISA). Keywords: coronavirus; COVID-19; laboratory diagnosis; SARS-CoV-2