Translation of aptamers toward clinical diagnosis and commercialization

The dominance of antibodies in diagnostics has gradually changed following the discovery of aptamers in the early 1990s. Aptamers offer inherent advantages over traditional antibodies, including higher specificity, higher affinity, smaller size, greater stability, ease of manufacture, and low immunogenicity, rendering them the best candidates for point-of-care testing (POCT). In the past 20 years, the research community and pharmaceutical companies have made great efforts to promote the development of aptamer technology. Macugen® (pegaptanib) was the first aptamer drug approved by the US Food and Drug Administration (FDA), and various aptamer-based diagnostics show great promise in preclinical research and clinical trials. In this review, we introduce recent literature, ongoing clinical trials, commercial reagents of aptamer-based diagnostics, discuss the FDA regulatory mechanisms, and highlight the prospects and challenges in translating these studies into viable clinical diagnostic tools.

Development and characterization of an indirect ELISA to detect SARS-CoV-2 spike protein-specific antibodies

The current Severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) pandemic is a public health emergency of international concern. Sensitive and precise diagnostic tools are urgently needed. In this study, we developed a SARS-CoV-2 spike (S1) protein enzyme-linked immunosorbent assay (ELISA) to detect SARS-CoV-2-specific antibodies. The SARS-CoV-2 S1 ELISA was found to be specific [97.8% (95% CI, 96.7% - 98.5%)], reproducible and precise (intra-assay coefficient of variability (CV) 5.3%, inter-assay CV 7.9%). A standard curve and the interpolation of arbitrary ELISA units per milliliter served to reduce the variability between different tests and operators. Cross-reactivity to other human coronaviruses was addressed by using sera positive for MERS-CoV- and hCoV HKU1-specific antibodies. Monitoring antibody development in various samples of twenty-three and single samples of twenty-nine coronavirus disease 2019 (COVID−19) patients revealed seroconversion and neutralizing antibodies against authentic SARS-CoV-2 in all cases. The comparison of the SARS-CoV-2 (S1) ELISA with a commercially available assay showed a better sensitivity for the in-house ELISA.

The results demonstrate a high reproducibility, specificity and sensitivity of the newly developed ELISA, which is suitable for the detection of SARS-CoV-2 S1 protein-specific antibody responses.

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A highly sensitive and specific SARS-CoV-2 S1 ELISA was developed.

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A standard curve is included to reduce variability between assays and operators.

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Excellent intra-assay coefficient of variability (CV) 5.3%, inter-assay CV 7.9%.

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Good correlation to the virus neutralization test VNT₁₀₀.

A novel antihuman C3d monoclonal antibody with specificity to the C3d complement split product

The complement component C3 and the cleavage products of C3b/iC3b, C3c and C3d are used as biomarkers in clinical diagnostics. Currently, no specific antibodies are able to differentiate C3d from other fragments, although such a distinction could be very valuable considering that they may reflect different pathophysiological mechanisms. We have developed a rat antihuman C3d monoclonal antibody with specificity to the end sequence of the N-terminal region of C3d. The antibody can therefore only bind to C3d when it manifests itself as the final end product of cleaved C3. We believe that this specificity is it first of its kind, and predicts that it can be used as a detection tool in several immunological methods with great value in diagnostics.

Assessment of the effects of repeated freeze thawing and extended bench top processing of plasma samples using untargeted metabolomics

INTRODUCTION

Clinical metabolomics has utility as a screen for inborn errors of metabolism (IEM) and variant classification in patients with rare disease. It is important to understand and characterize preanalytical factors that influence assay performance during patient sample testing.

OBJECTIVES

To evaluate the impact of extended thawing of human EDTA plasma samples on ice prior to extraction as well as repeated freeze-thaw cycling of samples to identify compounds that are unstable prior to metabolomic analysis.

METHODS

Twenty-four (24) donor EDTA plasma samples were collected and immediately frozen at - 80 °C. Twelve samples were thawed on ice and extracted for analysis at time 0, 2, 4, and 6 h. Twelve other donor samples were repeatedly thawed and frozen up to four times and analyzed at each cycle. Compound levels at each time point/freeze-thaw cycle were compared to the control samples using matched-paired t tests to identify analytes affected by each condition.

RESULTS

We identified 1026 biochemicals across all samples. Incubation of thawed EDTA plasma samples on ice for up to 6 h resulted in < 1% of biochemicals changing significantly. Freeze-thaw cycles affected a greater percentage of the metabolome; ~ 2% of biochemicals changed after 3 freeze-thaw cycles.

CONCLUSIONS

Our study highlights that the number and magnitude of these changes are not as widespread as other aspects of improper sample handling. In total, < 3% of the metabolome detected on our clinical metabolomics platform should be disqualified when multiple freeze-thaw cycles or extended thawing at 4 °C are performed on a given sample.

A sensitive epitope-blocking ELISA for the detection of Chikungunya virus-specific antibodies in patients

Chikungunya fever (CHIKF) has re-emerged as an arboviral disease that mimics clinical symptoms of other diseases such as dengue, malaria, as well as other alphavirus-related illnesses leading to problems with definitive diagnosis of the infection. Herein we describe the development and evaluation of a sensitive epitope-blocking ELISA (EB-ELISA) capable of specifically detecting anti-chikungunya virus (CHIKV) antibodies in clinical samples. The assay uses a monoclonal antibody (mAb) that binds an epitope on the E2 protein of CHIKV and does not exhibit cross-reactivity to other related alphaviruses. We also demonstrated the use of recombinant CHIK virus-like particles (VLPs) as a safe alternative antigen to infectious virions in the assay. Based on testing of 60 serum samples from patients in the acute or convalescent phase of CHIKV infection, the EB-ELISA provided us with 100% sensitivity, and exhibited 98.5% specificity when Ross River virus (RRV)- or Barmah Forest virus (BFV)-immune serum samples were included. This assay meets the public health demands of a rapid, robust, sensitive and specific, yet simple assay for specifically diagnosing CHIK-infections in humans.

Real-time fluorescence loop-mediated isothermal amplification assay for rapid and sensitive detection of Streptococcus gallolyticus subsp. gallolyticus associated with colorectal cancer

The increasing threat of Streptococcus gallolyticus subsp. gallolyticus (SGG) infections has gained considerable attention for its strong association with colorectal cancer (CRC). Herein, we proposed real-time fluorescence loop-mediated isothermal amplification (LAMP) as a novel, simple, rapid, and highly sensitive assay for identifying SGG for the first time. This assay was capable of detecting SGG with initial DNA concentrations ranging from 10² to 10⁸ copies per microliter, under isothermal conditions within 30 min via real-time fluorescence monitoring. Our method was tested for specific identification of SGG strains without cross-reaction with other Streptococcus gallolyticus subspecies and Escherichia coli. The developed LAMP shows a superior performance with shorter time and higher sensitivity compared with conventional polymerase chain reaction (PCR). Significantly, this proposed approach was successfully applied for detecting SGG in clinical urine samples, which is non-invasive diagnosis, showing excellent accuracy and reliability to discriminate healthy controls and CRC patients. For comparison, these samples were also tested against PCR assay. These results yielded an analytical sensitivity of 100% and a specificity of 100% for SGG testing using LAMP. The findings suggest LAMP can be employed for detecting SGG infections which is useful for diagnosis and screening of CRC.

[Clinical diagnosis and drug therapy of elderly patients with schizophrenia : A restrospective analysis of data in a department of old age psychiatry]

BACKGROUND

The objective of this study was to survey the consistency of the clinical diagnostics and the psychopharmacological treatment of schizophrenia and delusional disorders suffered by older persons. A further aspect was to record significant clinical differences and also similarities between the patient groups in care, matching with the criteria of ICD 10 for schizophrenia (F20), persistent delusional disorders (F22) and schizoaffective disorder (F25).

METHODS

Retrospective analysis with reference to the manually and electronically recorded patient medical records of an acute case care ward for geriatric psychiatry and psychotherapy.

RESULTS

During the assessment period 210 patients over the age of 65 years were included consecutively in the study (F20 - 64 patients, F22 - 78 patients, F25 - 64 patients, 4 patients died). Ignoring the fact that many of the patients were admitted without a diagnosis, the diagnostic classification of the referring doctor, above all those made by general practitioners, proved to be very consistent for the groups F20 and F25. In the group F22 diagnoses, however, up to almost one half of the referred patients were incorrectly admitted with an F20 diagnosis. The patients included in group F22 formed a heterogeneous group, or a melting pot for various sub-groups, with the common shared characteristic of being comprised of persons suffering from a delusional disorder. These differed from the other two groups in the following attributes: the patients were either older or very old persons, they were mostly receiving inpatient treatment for the first time and subsequently had fewer re-admissions. They also suffered more frequently from both psychiatric and somatic comorbidities; furthermore they included elderly people who had suffered from learning deficiencies or borderline intellectual deficiencies throughout their earlier lives. The patients in groups F20 and F25 differed primarily only in terms of their psychiatric medication, with significantly more mood stabilizer prescribed in the F25 group. Patients in all three groups frequently received tranquilisers during the day and sedatives in the evening, atypical antipsychotics were prescribed in the great majority of cases.

CONCLUSION

The referral diagnoses of patients suffering from many years of schizophrenic type illnesses were largely in compliance with the diagnostic criteria, a much more difficult issue for the referring doctors was the allocation of patients with a first occurrence of delusional symptoms. Those patients who were allocated to the diagnostic group schizophrenia differed significantly from patients from the group with delusional disorders.

Enhanced Performance of Colorimetric Biosensing on Paper Microfluidic Platforms Through Chemical Modification and Incorporation of Nanoparticles

This chapter describes two different methodologies used to improve the analytical performance of colorimetric paper-based biosensors. Microfluidic paper-based analytical devices (μPADs) have been produced by a stamping process and CO₂ laser ablation and modified, respectively, through an oxidation step and incorporation of silica nanoparticles on the paper structure. Both methods are employed in order to overcome the largest problem associated with colorimetric detection, the heterogeneity of the color distribution in the detection zones. The modification steps are necessary to improve the interaction between the paper surface and the selected enzymes. The enhanced performance has ensured reliability for quantitative analysis of clinically relevant compounds.

[Analysis of clinical diagnostic characteristics of 26131 patients with pneumoconiosis in Hunan Province]

Objective: To analyze the clinical diagnostic characteristics of pneumoconiosis patients of migrant workers in Hunan Province, and to provide scientific basis for the prevention and treatment of pneumoconiosis. Methods: In February 2022, through the Hunan Provincial Medical Treatment and Assistance Information Platform for Pneumoconiosis Migrant Workers, the cases of irresponsible subjects with pneumoconiosis that were first diagnosed clinically in Hunan Province from January 2017 to December 2021 were collected, and analyzed their gender, age, length of service, types of pneumoconiosis, stages of pneumoconiosis, and comorbidities. Results: From January 2017 to December 2021, there were a total of 26131 cases of irresponsible pneumoconiosis patients diagnosed clinically in Hunan Province, with males accounting for 99.8% (26072 cases) and an average age of (60.66±8.04) years old. Among the 26131 patients, coal workers' pneumoconiosis and silicosis were the main causes, with 16816 and 9078 cases respectively, accounting for 99.1% of the diagnosed cases. There were 8640 cases (33.1%) of stageⅠpneumoconiosis, 6601 cases (25.2%) of stage Ⅱ pneumoconiosis, and 10890 cases (41.7%) of stage Ⅲ pneumoconiosis. 2051 patients experienced complications. The average age of exposure to dust of 26131 patients was (17.81±9.69) years, and the age of exposure to dust in silicosis patients was (14.60±9.62) years. The working age of coal worker's pneumoconiosis was (19.60±9.26) years. Compared with coal workers' pneumoconiosis patients, silicosis patients had a shorter working time exposed to dust, and the difference was statistically significant (P<0.05) . Conclusion: Coal workers' pneumoconiosis and silicosis are mainly diagnosed for the first time in migrant workers' pneumoconiosis patients in Hunan Province. Pneumoconiosis patients should be diagnosed in time, which is conducive to treatment and rehabilitation.