Development Of Molecular Diagnostic Tests Research Articles

COVID-19 Diagnostic Strategies. Part I: Nucleic Acid-Based Technologies.

The novel Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has caused respiratory infection, resulting in more than two million deaths globally and hospitalizing thousands of people by March 2021. A considerable percentage of the SARS-CoV-2 positive patients are asymptomatic or pre-symptomatic carriers, facilitating the viral spread in the community by their social activities. Hence, it is critical to have access to commercialized diagnostic tests to detect the infection in the earliest stages, monitor the disease, and follow up the patients. Various technologies have been proposed to develop more promising assays and move toward the mass production of fast, reliable, cost-effective, and portable PoC diagnostic tests for COVID-19 detection. Not only COVID-19 but also many other pathogens will be able to spread and attach to human bodies in the future. These technologies enable the fast identification of high-risk individuals during future hazards to support the public in such outbreaks. This paper provides a comprehensive review of current technologies, the progress in the development of molecular diagnostic tests, and the potential strategies to facilitate innovative developments in unprecedented pandemics.

Abalone Viral Ganglioneuritis

Abalone viral ganglioneuritis (AVG), caused by Haliotid herpesvirus-1 (HaHV-1; previously called abalone herpesvirus), is a disease that has been responsible for extensive mortalities in wild and farmed abalone and has caused significant economic losses in Asia and Australia since outbreaks occurred in the early 2000s. Researchers from Taiwan, China, and Australia have conducted numerous studies encompassing HaHV-1 genome sequencing, development of molecular diagnostic tests, and evaluation of the susceptibility of various abalone species to AVG as well as studies of gene expression in abalone upon virus infection. This review presents a timeline of the most significant research findings on AVG and HaHV-1 as well as potential future research avenues to further understand this disease in order to develop better management strategies.

AGA Institute Rapid Review and Recommendations on the Role of Pre-Procedure SARS-CoV-2 Testing and Endoscopy

AGA Institute Rapid Review and Recommendations on the Role of Pre-Procedure SARS-CoV-2 Testing and Endoscopy

An Update on Clostridium difficile Toxinotyping.

Toxinotyping is a PCR-restriction fragment length polymorphism (RFLP)-based method for differentiation of Clostridium difficile strains according to the changes in the pathogenicity locus (PaLoc), a region coding for toxins A and B. Toxinotypes are a heterogenous group of strains that are important in the development of molecular diagnostic tests and vaccines and are a good basis for C. difficile phylogenetic studies. Here we describe an overview of the 34 currently known toxinotypes (I to XXXIV) and some changes in nomenclature.

In-depth proteomic analysis of carp (Cyprinus carpio L) spermatozoa

Using a combination of protein fractionation by one-dimensional gel electrophoresis and high performance liquid chromatography-electrospray ionization tandem mass spectrometry, we identified 348 proteins in carp spermatozoa, most of which were for the first time identified in fish. Dynein, tubulin, HSP90, HSP70, HSP60, adenosylhomocysteinase, NKEF-B, brain type creatine kinase, mitochondrial ATP synthase, and valosin containing enzyme represent high abundance proteins in carp spermatozoa. These proteins are functionally related to sperm motility and energy production as well as the protection of sperm against oxidative injury and stress. Moreover, carp spermatozoa are equipped with functionally diverse proteins involved in signal transduction, transcription, translation, protein turnover and transport. About 15% of proteins from carp spermatozoa identified here were also detected in seminal plasma which may be a result of leakage from spermatozoa into seminal plasma, adsorption of seminal plasma proteins on spermatozoa surface, and expression in both spermatozoa and cells secreting seminal plasma proteins. The availability of a catalog of carp sperm proteins provides substantial advances for an understanding of sperm function and for future development of molecular diagnostic tests of carp sperm quality, the evaluation of which is currently limited to certain parameters such as sperm count, morphology and motility or viability. The mass spectrometry data are available at ProteomeXchange with the dataset identifier PXD000877 (DOI: http://dx.doi.org/10.6019/PXD000877).

Cell-free urinary microRNA-99a and microRNA-125b are diagnostic markers for the non-invasive screening of bladder cancer.

BackgroundEvidence implicated the diagnostic significance of microRNAs in whole urine/urine sediments in urothelial carcinoma of the bladder (UCB). However, the contaminated blood cells in patients with haematouria significantly altered the expression profiles of urinary microRNA, influencing the test accuracy.MethodsMicroRNA profiles of the urine supernatants of UCB patients and controls without any malignancy and profiles of malignant and corresponding normal mucosa tissues from the patients were determined by microRNA microarray and compared to identify differentially expressed microRNAs. The differential expression was verified in the tissues of an independent patient cohort by RT-qPCR. The diagnostic significance of selected microRNAs as biomarkers in the urine supernatant was investigated in the expanded cohorts.ResultsMicroRNA-99a and microRNA-125b were down-regulated in the urine supernatants of UCB patients. The degree of down-regulation was associated with the tumor grade. A diagnostic model was developed using a combined index of the levels of microRNA-99a and microRNA-125b in the urine supernatant with a sensitivity of 86.7%, a specificity of 81.1% and a positive predicted value (PPV) of 91.8%. Discriminating between high- and low-grade UCB, the model using the level of microRNA-125b alone exhibited a sensitivity of 81.4%, a specificity of 87.0% and a PPV of 93.4%.ConclusionsThe results revealed a unique microRNA expression signature in the urine supernatants of UCB patients for the development of molecular diagnostic tests. An effective cell-free urinary microRNA-based model was developed using a combined index of the levels of microRNA-99a and microRNA-125b to detect UCB with good discriminating power, high sensitivity and high specificity.

OHP-039 The relevance of health technology assessment of diagnostic, prognostic and predictive tests in oncology. Prospects for implementation in Russia

BackgroundNowadays in cancer diagnosis and treatment a number of tests are used based on identification of different biomarkers. Testing capabilities in the field of oncology have been greatly enhanced with...

Modifier Gene Studies to Identify New Therapeutic Targets in Cystic Fibrosis

Since the discovery of the CFTR gene mutations which cause cystic fibrosis (CF) in 1989 the average life expectancy of CF patients has almost doubled and now exceeds 37 years. The advances in molecular diagnostics and medical treatments expanded beyond the CF patient population as some of the newest treatments are also being tested for treatment of complex diseases such as COPD and other inherited disorders. Rapid development of CF therapeutics is important for the cystic fibrosis community and is an excellent example for other nonprofit organizations, disease foundations and pharmaceutical companies alike. Better understanding of disease variability and underlying molecular mechanisms through genetic association studies aimed to identify novel CF modifier genes opens new venues for targeted drug design. Furthermore, these genetic studies allow development of molecular diagnostic tests for patient population stratification and treatment personalization, which is already being done for CF patients with specific mutations in the CFTR gene, as well as implementation of new molecular tests for reliable assessment of disease progression and severity.

Overview of Serological-Specific IgE Antibody Testing in Children

Allergic diseases are among the most common chronic conditions in the pediatric population. Allergy diagnostic testing is an important part of the evaluation/management of allergic patients because the history may not be precise enough to identify the specific allergen sensitivity. In addition to providing information about specific sensitivities, allergy diagnostic tests have some predictive value in terms of future risk of developing an allergic condition and the severity/persistence of the allergic disease. The two most commonly used methods of confirming allergen sensitization are skin testing and measurement of serum-specific IgE. Both methods have similar diagnostic value in terms of sensitivity and specificity, with both parameters varying with the clinical scenario and allergen tested. Currently, there are three US Food and Drug Administration-cleared, serum-specific IgE assays used in the United States. The three assays report comparable analytic sensitivity, with the coefficients of variation of the precision, reproducibility, and linearity being less than 15%. However, comparative studies have demonstrated significant inter-assay variability, suggesting that they detect different populations of IgE antibody in human sera or do not measure the same antibodies with the same efficiency. Current specific IgE assays utilize allergen extract reagents. Testing with these reagents may identify sensitivity to clinically irrelevant allergens. This diagnostic limitation has spurred the development of molecular diagnostic tests, also referred to as component-resolved diagnostics, which utilize purified native or recombinant allergens to detect IgE sensitivity to individual allergen molecules. These advancements in serum IgE testing may enhance the precision of allergy diagnostic testing, which may decrease the need for oral food challenges and improve the specificity of allergen immunotherapy.

A policy approach to the development of molecular diagnostic tests

Efficiently generating evidence of clinical utility is a major challenge for ensuring clinical adoption of valuable diagnostics. A new approach to reimbursement in the United States offers a balance between evidence and incentives for molecular diagnostic tests.

Inaugural Meeting of the Cysticercosis Working Group in Europe

Inaugural Meeting of the Cysticercosis Working Group in Europe

Sequence heterogeneity in the 18S rRNA gene within Theileria equi and Babesia caballi from horses in South Africa

A molecular epidemiological survey of the protozoal parasites that cause equine piroplasmosis was conducted using samples collected from horses and zebra from different geographical locations in South Africa. A total of 488 samples were tested for the presence of Theileria equi and/or Babesia caballi using the reverse line blot hybridization assay. Ten percent of the samples hybridized to the Theileria/ Babesia genus-specific probe and not to the B. caballi or T. equi species-specific probes, suggesting the presence of a novel species or genotype. The small subunit of rRNA gene (18S; ∼1600 bp) was amplified and sequenced from 33 of these 488 samples. Sequences were compared with published sequences from the public sequence databases. Twelve distinct T. equi and six B. caballi 18S rRNA sequences were identified. Alignments demonstrated extensive sequence variation in the V4 hypervariable region of the 18S rRNA gene within T. equi. Sequence variation was also found in B. caballi 18S rRNA genes, although there was less variation than observed for T. equi. Phylogenetic analysis based on 18S rRNA gene sequences revealed three T. equi clades and two B. caballi clades in South Africa. The extent of sequence heterogeneity detected within T. equi and B. caballi 18S rRNA genes was unexpected since concerted evolution is thought to maintain homogeneity within repeated gene families, including rRNA genes, in eukaryotes. The findings reported here show that careful examination of variants of the 18S rRNA gene of T. equi and B. caballi is required prior to the development of molecular diagnostic tests to detect these parasites in horses. Species-specific probes must be in designed in regions of the gene that are both conserved within and unique to each species.