scholarly journals All-Optical Planar Polymer Waveguide-Based Biosensor Chip Designed for Smartphone-Assisted Detection of Vitamin D

Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6771
Author(s):  
Johanna-Gabriela Walter ◽  
Lourdes S. M. Alwis ◽  
Bernhard Roth ◽  
Kort Bremer
Keyword(s):  
Large Scale ◽  
Simultaneous Detection ◽  
Serum Samples ◽  
Plasmonic Sensor ◽  
Assay Sensitivity ◽  
Lab On Chip ◽  
Polymer Waveguide ◽  
Hydroxyvitamin D ◽  
All Optical ◽  
Biosensor Chip

An all-optical plasmonic sensor platform designed for smartphones based on planar-optical waveguide structures integrated in a polymer chip is reported for the first time. To demonstrate the applicability of the sensor system for biosensing purposes, the detection of 25-hydroxyvitamin D (25OHD) in human serum samples using an AuNP-enhanced aptamer-based assay was demonstrated. With the aid of the developed assay sensitivity of 0.752 pixel/nM was achieved for 25OHD concentrations ranging from 0–100 nM. The waveguide structure of the sensor enables miniaturisation and parallelisation, thus, demonstrates the potential for simultaneous detection of various analytes including biomarkers. The entire optical arrangement can be integrated into a single polymer chip which allows for large scale and cost-efficient sensor fabrication. The broad utilization and access of smartphone electronics make the proposed design most attractive for its wider use in lab-on-chip applications.

scholarly journals Evaluation of a novel multiplexed assay for determining IgG levels and functional activity to SARS-CoV-2

2020 ◽  
Author(s):  
Marina Johnson ◽  
Helen R. Wagstaffe ◽  
Kimberly C. Gilmour ◽  
Annabelle Lea Mai ◽  
Joanna Lewis ◽  
...  
Keyword(s):  
Solid Phase ◽  
Simultaneous Detection ◽  
Serum Samples ◽  
Meso Scale Discovery ◽  
Assay Sensitivity ◽  
Rigorous Evaluation ◽  
Specificity And Sensitivity ◽  
Igg Binding ◽  
Control Serum ◽  
Multiplexed Immunoassay

AbstractBackgroundThe emergence of SARS-CoV-2 has led to the development of new serological assays that could aid in diagnosis and evaluation of seroprevalence to inform an understanding of the burden of COVID-19 disease. Many available tests lack rigorous evaluation and therefore results may be misleading.ObjectivesThe aim of this study was to assess the performance of a novel multiplexed immunoassay for the simultaneous detection of antibodies against SARS-CoV-2 trimeric spike (S), spike receptor binding domain (RBD), spike N terminal domain and nucleocapsid antigen and a novel pseudo-neutralisation assay.MethodsA multiplexed solid-phase chemiluminescence assay (Meso Scale Discovery) was evaluated for the simultaneous detection of IgG binding to four SARS-CoV-2 antigens and the quantification of antibody-induced ACE-2 binding inhibition (pseudo-neutralisation assay). Sensitivity was evaluated with a total of 196 COVID-19 serum samples (169 confirmed PCR positive and 27 anti-nucleocapsid IgG positive) from individuals with mild symptomatic or asymptomatic disease. Specificity was evaluated with 194 control serum samples collected from adults prior to December 2019.ResultsThe specificity and sensitivity of the binding IgG assay was highest for S protein with a specificity of 97.4% and sensitivity of 96.2% for samples taken 14 days and 97.9% for samples taken 21 days following the onset of symptoms. IgG concentration to S and RBD correlated strongly with percentage inhibition measured by the pseudo-neutralisation assay.ConclusionExcellent sensitivity for IgG detection was obtained over 14 days since onset of symptoms for three SARS-CoV-2 antigens (S, RBD and N) in this multiplexed assay which can also measure antibody functionality.

scholarly journals European Biological Variation Study (EuBIVAS): within- and between-subject biological variation estimates for serum thyroid biomarkers based on weekly samplings from 91 healthy participants

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Michela Bottani ◽  
Aasne K. Aarsand ◽  
Giuseppe Banfi ◽  
Massimo Locatelli ◽  
Abdurrahman Coşkun ◽  
...  
Keyword(s):  
Large Scale ◽  
Thyroid Stimulating Hormone ◽  
Biological Variation ◽  
Healthy Individuals ◽  
Serum Samples ◽  
Free Triiodothyronine ◽  
Performance Specifications ◽  
Study Population ◽  
Variance Homogeneity ◽  
Healthy Participants

Abstract Objectives Thyroid biomarkers are fundamental for the diagnosis of thyroid disorders and for the monitoring and treatment of patients with these diseases. The knowledge of biological variation (BV) is important to define analytical performance specifications (APS) and reference change values (RCV). The aim of this study was to deliver BV estimates for thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), thyroglobulin (TG), and calcitonin (CT). Methods Analyses were performed on serum samples obtained from the European Biological Variation Study population (91 healthy individuals from six European laboratories; 21–69 years) on the Roche Cobas e801 at the San Raffaele Hospital (Milan, Italy). All samples from each individual were evaluated in duplicate within a single run. The BV estimates with 95% CIs were obtained by CV-ANOVA, after analysis of variance homogeneity and outliers. Results The within-subject (CV I ) BV estimates were for TSH 17.7%, FT3 5.0%, FT4 4.8%, TG 10.3, and CT 13.0%, all significantly lower than those reported in the literature. No significant differences were observed for BV estimates between men and women. Conclusions The availability of updated, in the case of CT not previously published, BV estimates for thyroid markers based on the large scale EuBIVAS study allows for refined APS and associated RCV applicable in the diagnosis and management of thyroid and related diseases.

scholarly journals A non-targeted LC–MS metabolic profiling of pregnancy: longitudinal evidence from healthy and pre-eclamptic pregnancies

Metabolomics ◽  
2021 ◽  
Vol 17 (2) ◽  
Author(s):  
Tiina Jääskeläinen ◽  
◽  
Olli Kärkkäinen ◽  
Jenna Jokkala ◽  
Anton Klåvus ◽  
...  
Keyword(s):  
Large Scale ◽  
Scale Effects ◽  
Late Pregnancy ◽  
Metabolite Profile ◽  
Adverse Outcomes ◽  
Liquid Chromatography Mass Spectrometry ◽  
Targeted Metabolomics ◽  
Serum Samples ◽  
Healthy Women ◽  
Maternal Metabolism

Abstract Introduction Maternal metabolism changes substantially during pregnancy. However, few studies have used metabolomics technologies to characterize changes across gestation. Objectives and methods We applied liquid chromatography–mass spectrometry (LC–MS) based non-targeted metabolomics to determine whether the metabolic profile of serum differs throughout the pregnancy between pre-eclamptic and healthy women in the FINNPEC (Finnish Genetics of Preeclampsia Consortium) Study. Serum samples were available from early and late pregnancy. Results Progression of pregnancy had large-scale effects to the serum metabolite profile. Altogether 50 identified metabolites increased and 49 metabolites decreased when samples of early pregnancy were compared to samples of late pregnancy. The metabolic signatures of pregnancy were largely shared in pre-eclamptic and healthy women, only urea, monoacylglyceride 18:1 and glycerophosphocholine were identified to be increased in the pre-eclamptic women when compared to healthy controls. Conclusions Our study highlights the need of large-scale longitudinal metabolomic studies in non-complicated pregnancies before more detailed understanding of metabolism in adverse outcomes could be provided. Our findings are one of the first steps for a broader metabolic understanding of the physiological changes caused by pregnancy per se.

scholarly journals Low seroprevalence rates of Zika virus in Kuala Lumpur, Malaysia

2019 ◽  
Vol 113 (11) ◽  
pp. 678-684 ◽  
Author(s):  
I-Ching Sam ◽  
Magelda Montoya ◽  
Chong Long Chua ◽  
Yoke Fun Chan ◽  
Andrew Pastor ◽  
...  
Keyword(s):  
Zika Virus ◽  
Large Scale ◽  
Binding Assay ◽  
Seroprevalence Rate ◽  
Protective Effects ◽  
Kuala Lumpur ◽  
Serum Samples ◽  
Denv Serotypes ◽  
Population Immunity ◽  
Low Incidence

Abstract Background Zika virus (ZIKV) is believed to be endemic in Southeast Asia. However, there have been few Zika cases reported to date in Malaysia, which could be due to high pre-existing levels of population immunity. Methods To determine Zika virus (ZIKV) seroprevalence in Kuala Lumpur, Malaysia, 1085 serum samples from 2012, 2014–2015 and 2017 were screened for anti-ZIKV antibodies using a ZIKV NS1 blockade-of-binding assay. Reactive samples were confirmed using neutralization assays against ZIKV and the four dengue virus (DENV) serotypes. A sample was possible ZIKV seropositive with a ZIKV 50% neutralization (NT50) titre ≥20. A sample was probable ZIKV seropositive if, in addition, all DENV NT50 titres were <20 or the ZIKV NT50 titre was >4-fold greater than the highest DENV NT50 titre. Results We found low rates of possible ZIKV seropositivity (3.3% [95% confidence interval {CI} 2.4 to 4.6]) and probable ZIKV seropositivity (0.6% [95% CI 0.3 to 1.4]). Possible ZIKV seropositivity was independently associated with increasing age (odds ratio [OR] 1.04 [95% CI 1.02 to 1.06], p<0.0001) and male gender (OR 3.5 [95% CI 1.5 to 8.6], p=0.005). Conclusions The low ZIKV seroprevalence rate, a proxy for population immunity, does not explain the low incidence of Zika in dengue-hyperendemic Kuala Lumpur. Other factors, such as the possible protective effects of pre-existing flavivirus antibodies or reduced transmission by local mosquito vectors, should be explored. Kuala Lumpur is at high risk of a large-scale Zika epidemic.

scholarly journals Critical Aspects Concerning the Development of a Pooling Approach for SARS-CoV-2 Diagnosis Using Large-Scale PCR Testing

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 902
Author(s):  
Daniel Cruceriu ◽  
Oana Baldasici ◽  
Loredana Balacescu ◽  
Stefana Gligor-Popa ◽  
Mirela Flonta ◽  
...  
Keyword(s):  
Large Scale ◽  
Rna Extraction ◽  
Diagnostic Assay ◽  
Assay Sensitivity ◽  
Infected People ◽  
Multiple Parameters ◽  
Accurate Procedure ◽  
Manual Methods ◽  
Pooling Strategy ◽  
Critical Aspects

The primary approach to controlling the spread of the pandemic SARS-CoV-2 is to diagnose and isolate the infected people quickly. Our paper aimed to investigate the efficiency and the reliability of a hierarchical pooling approach for large-scale PCR testing for SARS-CoV-2 diagnosis. To identify the best conditions for the pooling approach for SARS-CoV-2 diagnosis by RT-qPCR, we investigated four manual methods for both RNA extraction and PCR assessment targeting one or more of the RdRp, N, S, and ORF1a genes, by using two PCR devices and an automated flux for SARS-CoV-2 detection. We determined the most efficient and accurate diagnostic assay, taking into account multiple parameters. The optimal pool size calculation included the prevalence of SARS-CoV-2, the assay sensitivity of 95%, an assay specificity of 100%, and a range of pool sizes of 5 to 15 samples. Our investigation revealed that the most efficient and accurate procedure for detecting the SARS-CoV-2 has a detection limit of 2.5 copies/PCR reaction. This pooling approach proved to be efficient and accurate in detecting SARS-CoV-2 for all samples with individual quantification cycle (Cq) values lower than 35, accounting for more than 94% of all positive specimens. Our data could serve as a comprehensive practical guide for SARS-CoV-2 diagnostic centers planning to address such a pooling strategy.

Age, gender and season dependent 25(OH)D levels in children and adults living in Istanbul

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Zeynep Yildiz ◽  
Özlem Hürmeydan ◽  
Özlem Çakır Madenci ◽  
Asuman Orçun ◽  
Nihal Yücel
Keyword(s):  
Large Scale ◽  
Population Characteristics ◽  
Healthcare Outcomes ◽  
Hydroxyvitamin D ◽  
Large Scale Data ◽  
Laboratory Results ◽  
Turkish People ◽  
Adults And Children ◽  
25 Hydroxyvitamin D ◽  
Scale Data

AbstractBackgroundWe evaluated population characteristics of serum 25-hydroxyvitamin D (25(OH)D) levels and determined the influence of age, gender and season in an extensive dataset.Materials and methodsLaboratory results of 103,509 adults and 19,186 children were retrospectively evaluated. Study group was classified regarding ages as; <40, 40–50, 50–60 and >60 years for adults and 0–1, 1–12 months,1–3, 4–6, 7–9, 10–12, 13–15 and 16–18 years for children. Seasonal values were also determined. Levels were measured by Architect i1000 SR (Abbott Diagnostics, USA).ResultsThe median (2.5–97.5 percentiles) of 25(OH)D levels were 38.75 (9.5–158.25) nmol/L for adults and 43.25 (11.25–125.5) nmol/L for children. There were significant gender differences for both adults and children. Values differed significantly among age subgroups (p’s < 0.01). A total of 63% of adults and 59.5% of children had 25(OH)D levels below 50 nmol/L (p < 0.001). 25(OH)D levels were significantly lower in the winter compared with summer (p’s < 0.001). Even levels in summer were moderate deficient for all group.ConclusionThe rate of 25(OH)D deficiency was remarkable during the whole year. This will provide large-scale data about 25(OH)D status in Turkish people and may contribute to the prevention and treatment of this condition for better healthcare outcomes.

A rat granulosa cell plasminogen activator bioassay for FSH in human serum

1990 ◽  
Vol 126 (1) ◽  
pp. 159-168 ◽  
Author(s):  
A. N. Thakur ◽  
R. Coles ◽  
A. Sesay ◽  
B. Earley ◽  
H. S. Jacobs ◽  
...  
Keyword(s):  
Human Serum ◽  
Plasminogen Activator ◽  
Granulosa Cell ◽  
Serum Samples ◽  
Glycoprotein Hormone ◽  
Assay Sensitivity ◽  
Serum Factors ◽  
Human Serum Samples ◽  
Heat Treated ◽  
Fsh Bioactivity

ABSTRACT A previously described in-vitro rat granulosa cell plasminogen activator bioassay for FSH has been modified and applied in the assay of human serum. This modified method consists of exposing the diethylstilboestrol-stimulated granulosa cells from 25- to 26-day-old rats to FSH or test substance for 3·5 h in wells coated with 125I-labelled fibrinogen and treated with thrombin. Following stimulation with FSH, the dose-related production of plasminogen activator was measured as the degree of 125I-labelled fibrinolysis in the presence of added plasminogen. Using the urinary FSH/LH bioassay reference preparation as the assay standard, the useful range of the assay was 0·3–15IU/l, with an assay sensitivity of 0·3 IU/l. As determined using purified glycoprotein hormone preparations, the assay was highly specific for FSH. The minor degree of FSH bioactivity measured in some of the hormone preparations was accounted for by the amount of FSH contamination in these preparations. To abolish interference caused by unknown serum factors, we heat-treated the serum samples for 15 min at 56 °C before the assay. The results indicated that neither immunoreactivity nor bioactivity was affected by this treatment. Furthermore, heat-treated human sera gave responses parallel to the standard curve at the three dose levels (2, 4 and 8 μl) studied. We used this bioassay to estimate the FSH-like bioactivity in 15 human serum samples. The estimates of immunoreactive FSH in these samples correlated well with the corresponding FSH bioactivity (r = 0·745, n = 15 and P < 0·05). The results indicate that with this sensitive and rapid (completed within 24 h) bioassay, it should be possible to measure FSH bioactivity in heat-treated human serum samples. Journal of Endocrinology (1990) 126, 159–168

Large-scale integration of wavelength-addressable all-optical memories on a photonic crystal chip

2014 ◽  
Vol 8 (6) ◽  
pp. 474-481 ◽  
Author(s):  
Eiichi Kuramochi ◽  
Kengo Nozaki ◽  
Akihiko Shinya ◽  
Koji Takeda ◽  
Tomonari Sato ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Large Scale ◽  
Optical Memories ◽  
All Optical ◽  
Large Scale Integration ◽  
Scale Integration

scholarly journals COVID-19 Disease Severity and Death in Relation to Vitamin D Status among SARS-CoV-2-Positive UAE Residents

Nutrients ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1714
Author(s):  
Habiba AlSafar ◽  
William B. Grant ◽  
Rafiq Hijazi ◽  
Maimunah Uddin ◽  
Nawal Alkaabi ◽  
...  
Keyword(s):  
Vitamin D ◽  
United Arab Emirates ◽  
Blood Levels ◽  
Vitamin D Status ◽  
Hospital Visit ◽  
Serum Samples ◽  
Hydroxyvitamin D ◽  
Increased Risk ◽  
Multiethnic Population ◽  
25 Hydroxyvitamin D

Insufficient blood levels of the neurohormone vitamin D are associated with increased risk of COVID-19 severity and mortality. Despite the global rollout of vaccinations and promising preliminary results, the focus remains on additional preventive measures to manage COVID-19. Results conflict on vitamin D’s plausible role in preventing and treating COVID-19. We examined the relation between vitamin D status and COVID-19 severity and mortality among the multiethnic population of the United Arab Emirates. Our observational study used data for 522 participants who tested positive for SARS-CoV-2 at one of the main hospitals in Abu Dhabi and Dubai. Only 464 of those patients were included for data analysis. Demographic and clinical data were retrospectively analyzed. Serum samples immediately drawn at the first hospital visit were used to measure serum 25-hydroxyvitamin D [25(OH)D] concentrations through automated electrochemiluminescence. Levels < 12 ng/mL were significantly associated with higher risk of severe COVID-19 infection and of death. Age was the only other independent risk factor, whereas comorbidities and smoking did not contribute to the outcomes upon adjustment. Sex of patients was not an important predictor for severity or death. Our study is the first conducted in the UAE to measure 25(OH)D levels in SARS-CoV-2-positive patients and confirm the association of levels < 12 ng/mL with COVID-19 severity and mortality.

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