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18 recordsLinked to original sources
PubMed1977

Evaluation of a standardised assay for the measurement of antibodies to double-stranded (native) DNA.

A standardised commercially available radioimmunoassay kit for the detection of antibodies to native DNA (N-DNA) has been evaluated in clinical practice. This test system is shown to be a reliably reproducible method of detecting these antibodies. In addition, evaluation of the purity of the radiolabelled test antigen in this assay has shown it to be almost entirely double stranded (native) DNA with virtually no contamination with single stranded (denatured) DNA, and with few areas of single stranded breaks or ends in the duplex molecule. The inclusion of known standards and precise characterisation of the DNA has partially overcome variability in results and provides for interlaboratory standardisation which is lacking in the techniques used at present.

Antibodies, Antinuclear↗
PubMed2026

Genomic, transcriptomic, and molecular predictors of response to neoadjuvant therapy in locally advanced rectal cancer: a narrative review.

Total neoadjuvant therapy (TNT) has emerged as a key treatment paradigm for locally advanced rectal cancer, reducing distant metastasis rates and facilitating organ preservation in selected patients. However, treatment response remains heterogeneous, highlighting the need for biomarkers that can guide treatment selection and optimise outcomes. This narrative review synthesises the current evidence regarding tumour-intrinsic genomic biomarkers associated with response to neoadjuvant therapy, encompassing somatic mutations, germline polymorphisms, gene expression profiles, mismatch repair (MMR) status, protein expression, epigenetic markers, and circulating tumour-derived biomarkers across conventional chemoradiotherapy (CRT) and TNT paradigms. Across the reviewed literature, individual somatic mutations, including KRAS, TP53, and BRAF, demonstrated limited reproducibility as predictive biomarkers, although KRAS mutations were recurrently associated with lower pathological complete response (pCR) rates in CRT-era cohorts. Germline polymorphisms in DNA repair (XRCC1) and folate metabolism (MTHFR) genes showed inconsistent associations with treatment response. In contrast, transcriptomic biomarkers demonstrated greater biological coherence, with proliferative, epithelial-mesenchymal transition, and metabolic signatures frequently associated with treatment resistance, while multi-gene classifiers generally outperformed single-gene markers. Among currently available tumour-intrinsic biomarkers, MMR deficiency was the most consistently reported biomarker associated with reduced response to fluoropyrimidine-based regimens, including TNT, although TNT-specific evidence remains comparatively limited. Dynamic circulating tumour DNA (ctDNA) monitoring, particularly ctDNA clearance during or after therapy, was consistently associated with pathological response and long-term oncologic outcomes across reviewed studies, whereas baseline ctDNA levels showed limited predictive value. Overall, the reviewed literature suggests that biomarker research in rectal cancer has evolved from single-gene analyses towards pathway-level and dynamic biomarkers. The integration of transcriptomic signatures, MMR status, and dynamic ctDNA monitoring may represent a promising strategy for personalising neoadjuvant therapy, improving patient selection for organ-preserving approaches, and enhancing oncologic outcomes in locally advanced rectal cancer. Nevertheless, the evidence base remains heterogeneous, and further prospective validation, assay standardisation, and evaluation within contemporary TNT cohorts are required before these biomarkers can be routinely incorporated into clinical decision-making.

Humans↗
PubMed1979

Nephelometric detection of circulating immune complexes using monoclonal rheumatoid factor.

A nephelometric technique for the estimation of immune complexes (IC) in serum was developed using purified monoclonal rheumatoid factor from a human patient (mRhF) specific for complexed IgG. Standardisation of the assay was carried out with heat aggregated normal human IgG as a model complex and with IC composed in vitro from ovalbumin and rabbit antisera to ovalbumin. The nephelometric method was compared with [125I]Clq radioimmunoassay (C1q RIA). The lower limits of detection by the two methods were similar for both aggregated IgG and performed ovalbumin/rabbit anti-ovalbumin IC. However, recognition of IC by the two methods differed with different ratios of antigen and antibody. When IC were formed at 10 times antigen excess the nephelometric technique was more sensitive than when IC were formed at equivalence or 10 times antibody excess. The Cuq RIA method was most sensitive in detection of IC in antibody excess but failed to detect IC in antigen excess. Complexes formed in antigen excess also showed potentiated light scattering when 1.5% polyethylene glycol was used in the nephelometric system. The incidence of IC detected by the mRhF in sera from patients with rheumatoid arthritis and systemic lupus erythematosus was lower than with C1q RIA suggesting that the IC in these patients contain antibodies not detected by the mRhF used. IC in the sera of patients with melanoma were detected more frequently by the mRhF assay which may indicate the IC in these sera were in antigen excess. Detection of IC by mRhF nephelometry was rapid, technically simple and yielded results which complemented those of the established C1q RIA method. This assay system is a useful addition to methods currently available for detection of IC and the similar use of rheumatoid factors against different classes of antibody should extend its usefulness.

Antigen-Antibody Complex↗
PubMed2026

Proteomics as a theranostic compass in BCR::ABL1-negative myeloproliferative neoplasms: Integrating biomarker discovery with therapeutic stratification.

Classic BCR::ABL1-negative myeloproliferative neoplasms (MPNs)-polycythaemia vera, essential thrombocythaemia, and primary myelofibrosis-are clonal haematopoietic stem cell disorders with marked heterogeneity in clinical phenotype, disease trajectory, and therapeutic response. Genomic stratification by driver and cooperating mutations only partially accounts for this variability, leaving gaps in predicting thrombotic risk, fibrotic progression, leukaemic transformation, and treatment benefit. Proteomics bridges this gap by providing function-proximal readouts of protein abundance, post-translational modifications, pathway activity, and intercellular signalling that genomics and transcriptomics cannot capture, positioning it as a theranostic platform in which the same molecular readouts simultaneously inform diagnostic stratification and therapeutic decision-making. We propose a five-stage translational framework spanning from discovery-scale mass spectrometry and affinity-based plasma profiling to targeted validation, multicentre standardisation, and machine learning-integrated clinical panels. Proteomic evidence is synthesised across the following four disease axes: clonal fitness in haematopoietic stem and progenitor cells; bone marrow microenvironmental remodelling and fibrosis; chronic inflammation and thrombosis; and leukaemic transformation. We further describe how phosphoproteomics reveals resistance mechanisms to JAK inhibitors, including AXL-MAPK bypass and PP2A-autophagy-mediated tolerance, and how protein-level biomarkers (BCL2-BCL-XL, RAS-ERK, CAMK2G, and ROCK1/2) can guide individualised therapeutic selection. Affinity-based platforms (Olink PEA and SomaScan) and spatially resolved technologies (CODEX and single-cell proteomics) complement discovery proteomics. At present, however, this evidence base is constrained by small and heterogeneous cohorts, limited cross-platform reproducibility, and a scarcity of independent external validation for candidate protein panels. Realising this vision will require multicentre standardisation, analytically validated panel assays, and prospective clinical studies that translate molecular findings into decision-grade tools for patients with MPNs.

Humans↗
PubMed2026

Assay-dependent variability in peptide biomarker quantification: experimental evidence from renalase in chronic kidney disease.

BACKGROUND: Renalase is a promising biomarker for kidney disease, but published levels vary widely between studies. We hypothesised that variability in commercial enzyme-linked immunosorbent assays (ELISAs) kits and matrix effects (serum vs plasma) drive these inconsistencies. METHODS: Paired serum and plasma samples from 56 participants (28 chronic kidney disease (CKD) stages 2-5, 28 healthy controls) were tested using three commercial renalase ELISAs (BTLAB, Cloud-Clone, EIAab). We assessed intra-assay precision, inter-assay agreement (Spearman's rank correlation and Bland-Altman analysis on log10-transformed values), matrix effects, and associations with estimated glomerular filtration rate (eGFR). Diagnostic performance was evaluated by Receiver operating characteristic (ROC) analysis. RESULTS: Inter-assay renalase concentrations differed markedly (up to orders of magnitude), with weak inter-assay correlations (r&#x2009;&#x2264;&#x2009;0.25). Bland-Altman analyses revealed large, systematic biases between kits. Only the BTLAB assay showed consistent serum/plasma agreement, a significant correlation with eGFR (&#x3c1;&#x2009;&#x2248;&#x2009;0.32-0.42, p&#x2009;<&#x2009;0.05), and moderate discriminatory performance for CKD in serum (AUC = 0.70) and plasma (AUC = 0.68). Cloud-Clone and EIAab produced divergent results and strong matrix-dependent biases. CONCLUSIONS: Observed variability among commercial ELISA platforms may compromise comparability between studies. Harmonisation, standardised reference materials, and cross-validation are necessary before renalase assays can be used reliably in clinical practice.

Humans↗
PubMed1977

Enzymes of galactose metabolism in human hair roots.

Micro-methods, making use of radioactive substrates, are described for the quantitative estimation of galactokinase and galactose-1-phosphate uridyl transferase activities in lysates of hair roots obtained from the human scalp. Enzyme assays can be carried out with fractions of one hair root. Both enzymes have been investigated with regard to stability, pH optimum and Michaelis-Menten constants. Along with similarities there were also certain differences as compared to galactokinase and galactose-1-phosphate uridyl transferase activities in other human tissues. The findings were used to optimise and standardise a radiochemical micro-assay for both enzymes in human hair root lysates, applicable to carrier detection studies in galactosaemia, an inborn error of carbohydrate metabolism. Because they can easily be obtained, hair roots are a very suitable biopsy material for both fundamental and diagnostic investigations of these enzymes.

Clinical Enzyme Tests↗
PubMed1978

Clinical use of plasma renin assays.

The use of plasma renin assays in clinical practice is reviewed and experience with an assay for plasma renin activity (PRA) is reported. In normal subjects, 10am ambulant PRA was significantly related to plasma angiotensin II levels but not related to daily urine sodium exretion in these subjects consuming normal diets. PRA was suppressed in patients with mineralocorticoid hypertension and in a small proportion of patients with essential hypertension. Very high values were observed in patients with untreated primary adrenal insufficiency, treatment of which resulted in a prompt fall of PRA to normal. PRA was usually normal in adrenalectomised patients and those with chronic adrenal insufficiency receiving satisfactory steroid replacement therapy. It is concluded that provided standardised conditions are used for the collection and assay, PRA is helpful in the assessment of hypokalaemic hypertension as well as in the early detection and management of patients with primary adrenal insufficiency or related conditions of salt wasting.

Adolescent↗
PubMed2026

Plasma proteomics: considerations for preanalytical variability; a systematic review with narrative synthesis.

BACKGROUND: The plasma proteome (PP) is a dynamic system subject to pathology-associated changes and a focus for novel disease biomarker discovery. Disease-related PP research assumes protein concentrations in test specimens accurately reflect the in&#xa0;vivo milieu. However, measures to maintain the physicochemical integrity of the proteome before assay are often rudimentary, poorly described, or lacking standardisation in published studies. Contrastingly, in laboratory medicine, there is an expectation that errors in the so-called "preanalytical phase" (PAP) that impact patient results are understood, monitored, and mitigated against, while also being well described in research publications. There is therefore scope for good practice from laboratory medicine to inform PP research workflows. This review considers factors in the PAP which may impact the validity of PP results. CONTENT: A systematic review was conducted per PRISMA guidelines, limited to English-language peer-reviewed studies (2014-2024). Candidate studies were imported, screened, and managed using Covidence systematic review software. SUMMARY: 15 eligible studies were reviewed, covering many relevant processes. 11 studies reported statistically significant differences in PP due to factors in the PAP. Temperature and time-to-processing were the most commonly reported factors affecting the PP, with significant effects reported in 8 studies. OUTLOOK: PAP variability can significantly affect results in PP studies. Careful consideration of the effect of each stage of the PAP is needed when working with the PP. In multicenter studies, pre-defined and research question-specific sample processing workflows are essential for reducing PAP variability, which helps ensure the validity of PP studies.

Humans↗
PubMed2026

Detection of antibiotic heteroresistance in clinical microbiology: current and emerging methodologies.

BACKGROUND: Antibiotic heteroresistance (HR) is characterised by the coexistence of susceptible and resistant subpopulations within an apparently isogenic bacterial isolate. Because routine antimicrobial susceptibility testing (AST) primarily assesses the dominant population, HR may escape detection, potentially leading to discrepancies between laboratory susceptibility categorisation and the underlying bacterial population structure. OBJECTIVES: To provide a critical and practice-oriented evaluation of current and emerging methodologies for HR detection and to discuss their strengths, limitations, and potential for clinical implementation. SOURCES: Narrative review based on PubMed searches, complemented by screening of key reference lists and relevant EUCAST and CLSI documents. Peer-reviewed literature was prioritised. CONTENT: Phenotypic approaches, particularly population analysis profiling, remain the reference method for HR definition, but their labour-intensive workflows, long turnaround times, and limited standardisation restrict routine implementation. Alternative strategies, including modified AST assays, metabolic assays, and single-cell platforms, offer gains in speed or throughput but require broader validation. Molecular approaches such as quantitative PCR, droplet digital PCR, targeted deep sequencing, and whole-genome sequencing improve detection of minority resistance determinants. Emerging computational frameworks, including machine learning models integrating phenotypic and genomic data, represent a promising frontier for scalable HR prediction. IMPLICATIONS: Available evidence supports the clinical relevance of HR, although its association with adverse outcomes varies across bacterial species and antibiotic classes. Harmonised methodologies and clinically validated interpretive criteria are needed to support integration of HR assessment into routine diagnostics. Prospective multicentre studies and further standardisation, including engagement with EUCAST and CLSI, will be important to advance clinical implementation.

Antimicrobial resistance↗
PubMed2026

Network-based integration of metabolomics data from large-scale repositories.

INTRODUCTION: Public metabolomics data repositories such as MetaboLights and Metabolomics Workbench host rapidly growing volumes of raw data, processed results, and metadata. As data deposition becomes a prerequisite for funding and publication, there is an increasing need for tools that enable integration and joint reanalysis of datasets across studies to maximise reuse and reproducibility. OBJECTIVES: This study aims to enable large-scale integrative meta-analysis of public metabolomics data, exploiting harmonised metabolite annotations to identify robust multi-study metabolite and pathway signatures and to provide global visual overviews of repository content. METHODS: We developed a network-based integration framework operating at both the study (dataset) level and the metabolite or pathway level. Metabolite-level meta-networks integrate studies with shared biological context using co-occurrences of differential metabolites represented as bipartite graphs. Study-level networks compare observed metabolites for overall repository exploration. Networks can be explored interactively using a dedicated Python Dash app available at https://github.com/EloisaRL/Metabolomic-data-analysis-app/tree/main . RESULTS: As an example, the approach was applied to six COVID-19 plasma datasets from MetaboLights generated using LC-MS and NMR. Ten metabolites were identified as differential in at least three studies, including consistently up-regulated pyroglutamic acid, in agreement with the literature. Pathway-level networks provided an overview of shared biological processes across studies. A global network of 1,181 studies in Metabolomics Workbench demonstrated clustering by assay coverage and associated metadata, as expected. CONCLUSION: Network-based integration of harmonised metabolomics data enables robust cross-study analyses and highlights the critical importance of standardised annotation pipelines. Such approaches enhance the reuse, reproducibility, and impact of public metabolomics datasets, accelerating biological discovery.

Metabolomics↗
PubMed1979

[Determination of lysozyme in biological fluids by a semi-automatic kinetic technique. Discussion of the method (author's transl)].

A rapid and semi-automatic determination of lysozyme in biological fluids using kinetic analysis and turbidimetry is described and compared to other commonly used techniques. The specificity of the method is satisfactory while that of clarification of a gel medium is apparently not. Normal values and standard errors for plasma, urine, and leucocytes are given. A standardised expression of lysozyme activity is proposed and discussed. The importance of the means by which the blood sample is collected and prepared is underlined: plasma, decanted soon after collection, is preferable to serum.

Autoanalysis↗
PubMed1979

An objective look at acid phosphatase determinations: a comparison of biochemical and immunological methods.

Measurements of serum and bone marrow acid phosphatase were made by 3 enzymatic methods, alpha-naphthyl phosphate, beta-glycerol phosphate, and thymolphthalein monophosphate, and ocmpared to a double antibody radioimmunoassay. Serum and bone marrow acid phosphatase levels were studied in 46 controls with histologically proven benign prostatic hyperplasia and in 135 patients with various stages of prostatic carcinoma. In the control group the upper limit for bone marrow acid phosphatase was found to be significantly higher than the corresponding serum limit with respect to the enzymatic assays studied. The radioimmunoassay was the only method suitable for the analysis of the prostatic acid phosphatase content of bone marrow. A larger number of elevations were noted in patients with extracapsular and metastatic disease when prostatic acid phosphatase measurement was carried out by radioimmunoassay as compared to enzymatic methods. However, only 8% of the patients with intracapsular disease had elevations of prostatic acid phosphatase as measured by radioimmunoassay. Additional standardisation of immunological methods and clinical trials is required before comparison can be made of results from various centres using immunological methods for the measurement of prostatic acid phosphatase and a true assessment made of the usefulness of this procedure.

Acid Phosphatase↗
PubMed2026

Standardisation in the Analytical Characterization of Adeno-Associated Virus (AAV) Vectors.

Adeno-associated virus (AAV) has become a leading vector for in vivo gene therapy, with eight products currently holding marketing authorization. As the field rapidly evolves, the need for robust analytical methods to characterize critical quality attributes (CQAs)-including capsid titer, genome titer, capsid content (empty/full ratio), identity, and purity-continues to grow. Reference Standard Materials (RSMs) play a pivotal role by providing well-characterized, standardized AAV batches that serve as universal benchmarks. RSMs facilitate the validation of emerging analytical technologies, ensure the accuracy and reproducibility of routine assays, and enable inter-laboratory comparability. However, developing universal AAV RSMs is fundamentally constrained by the complex biology, diversity of serotypes, vector genomes, and engineered capsid variants, necessitating serotype-specific and application-specific standards. Recent advances, including the release of pharmacopeial AAV8 reference standards characterized by multiple orthogonal methods, represent meaningful progress toward measurement harmonisation. This review addresses the critical need for RSMs in AAV gene therapy, evaluates the currently available pharmacopeial and commercial standards, and outlines practical strategies for in-house RSM development. Establishing robust, serotype-specific AAV RSMs and harmonised standard operating protocols (SOPs) are essential for advancing AAV gene therapy and ensuring accuracy, reproducibility, and safety across research, development, and clinical manufacturing.

Dependovirus↗
PubMed1979

An improved radioenzymatic assay for histamine in human plasma, whole blood, urine, and gastric juice.

A radioenzymatic method suitable for the assay of histamine in human blood, urine, plasma, and gastric juice is described. It differs from earlier methods by use of a histamine methyltransferase preparation from pig brain, of high activity tritiated S-adenosylmethionine, and of a heat precipitation step to reduce the previously noted interference from plasma constituents. The method is simpler than those requiring solvent extraction and concentration of histamine, gives recoveries in the range 80-120%, and so sliminates the need for internal standardisation. The method is sensitive and precise with coefficients of variation for blood, urine, and plasma of 5%, 6%, and 13% respectively. The mean +/- standard deviation for normal human plasma histamine is 5 +/- 4 nmol/l, for whole blood 559 +/- 193 nmol/l, and for urine 229 +/- 128 nmol/24h.

Animals↗
PubMed2026

DNA methylation biomarkers for early detection of ovarian cancer.

Ovarian cancer (OC) remains difficult to detect at an early stage, and current screening approaches using CA125 and transvaginal ultrasonography have not demonstrated sufficient benefit for population screening. DNA methylation is a promising biomarker class because epigenetic alterations may arise early in tumourigenesis, can be detected in circulating cell-free DNA (cfDNA), and may provide tissue-of-origin information. This review critically evaluates recent evidence on DNA methylation biomarkers for early OC detection. PubMed/MEDLINE, Web of Science, and Scopus were searched for studies published between January 2020 and September 2025, supplemented by selected earlier studies of biological or methodological relevance. Evidence was synthesised across single-gene biomarkers, multi-locus panels, genome-wide signatures, assay platforms, and machine-learning classifiers, with emphasis on early-stage performance, histological representation, comparator populations, analytical methodology, and validation design. Single-gene markers such as BRCA1, RASSF1A, OPCML, HOXA9, and HIC1 show variable performance, while multi-gene and classifier-based approaches generally provide stronger discrimination. However, many studies remain limited by retrospective case-control designs, small FIGO stage I-II subsets, predominance of serous disease, and insufficient prospective validation. Integration with CA125 may improve sensitivity but can reduce specificity, which is critical in low-prevalence screening. Clinical translation will therefore require minimal and reproducible methylation signatures, standardised low-input cfDNA workflows, rigorous external validation, and prospective longitudinal evaluation in intended-use populations.

Humans↗