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PubMed2025

Diagnostic performance of the Sanity 2.0 assay to detect resistance to rifampicin, isoniazid, and fluoroquinolones in tuberculosis.

UNLABELLED: Effective tuberculosis (TB) management relies on prompt diagnosis of Mycobacterium tuberculosis complex (MTBC) and associated drug resistance. The Sanity 2.0 assay is a high-resolution melting assay designed for direct respiratory sample testing, enabling simultaneous detection of MTBC and resistance to rifampicin (RIF), isoniazid (INH), and fluoroquinolones (FQ) in a single step. This study evaluated its diagnostic performance in two registered multicenter trials among bacteriologically confirmed TB patients. Diagnostic performance was evaluated for MTBC detection, as well as for the identification of resistance to RIF, INH, and FQ, using phenotypic drug susceptibility testing, whole-genome sequencing, and a composite reference standard. Agreement analyses were conducted between the Sanity 2.0 assay and Xpert MTB/RIF and Xpert MTB/XDR. Among 611 patients, the Sanity 2.0 assay detected MTBC in 563 patients, exhibiting a sensitivity of 92.1% (95% CI: 89.7-94.0). For detecting resistance to RIF, INH, and FQ, sensitivities exceeded 90%, with specificities of 95.8% (95% CI: 88.5-98.6), 100.0% (95% CI: 96.4-100.0), and 97.8% (95% CI: 93.8-99.3) against the composite reference standard, respectively. The agreement with Xpert MTB/RIF for RIF detection was 98.6% (95% CI: 96.9-99.3). For INH and FQ resistance, the agreement with Xpert MTB/XDR was 92.0% (95% CI: 88.5-94.5) and 94.3% (95% CI: 91.2-96.3), respectively. The Sanity 2.0 assay is a rapid and user-friendly platform capable of detecting both MTBC and key drug resistance. It demonstrated good diagnostic performance and could potentially be an effective alternative to guide individualized anti-TB treatment, especially in resource-limited settings. IMPORTANCE: Rapid and accurate detection of both Mycobacterium tuberculosis complex (MTBC) and key drug resistance is critical to improving tuberculosis treatment outcomes and reducing transmission. However, current molecular diagnostic workflows often require sequential testing, which can delay the initiation of effective and individualized therapy. We evaluated the Sanity 2.0 assay, an integrated high-resolution melting test that simultaneously detects MTBC and resistance to rifampicin, isoniazid, and fluoroquinolone resistance directly from respiratory samples in about 2-3 hours. The assay demonstrated excellent performance, with MTBC detection sensitivity of 92.1% and drug resistance sensitivities exceeding 90% and specificities over 95% against a composite reference standard, as well as strong concordance with World Health Organization-endorsed molecular assays. Implementation of the Sanity 2.0 assay could streamline TB diagnostic workflows; enable rapid, single-step resistance profiling; and facilitate timely, individualized treatment-particularly in resource-limited settings where rapid and comprehensive resistance testing remains a critical unmet need.

Humans↗
PubMed1977

Mouse potency assay for Bordetella bronchiseptica bacterins.

A potency assay for Bordetella bronchiseptica bacterins has been developed using mice. The immunogenicities of three bacterins, B, C, and D, were evaluated for ability to prevent death in mice as compared with a reference standard bacterin (RSB-A). Bacterins RSB-A, B, and C were evaluated for ability to prevent death in mice as compared with a reference standard bacterin (RSB-A). Bacterins RSB-A, B, and C were evaluated in swine for efficacy against nasal turbinate atrophy. Swine immunized with RSB-A demonstrated 25% gross nasal turbinate atrophy (GNTA), whereas nonimmunized swine had 85% GNTA. Swine vaccinated with bacterins B and C demonstrated 0 and 100% GNTA, respectively, whereas the nonimmunized groups had 64 and 75% GNTA, respectively. RSB-A and bacterins B, C, and D provided average mouse survivals of 94, 88, 49, and 32%, respectively when the mice were given 1/10,000 of a recommended swine-immunizing dose, whereas an average of 88% of the unvaccinated mice died.

Animals↗
PubMed1977

Synthesis and gastric antisecretory properties of 15-deoxy-16-hydroxyprostaglandin E analogues.

The preparation and gastric antisecretory activity of a series of 15-deoxy-16-hydroxyprostaglandin analogues are described. The compounds were tested intravenously in histamine-stimulated Heidenhain pouch dogs in relation to the reference standards PGE1 and PGE1 methyl ester (PGE1ME). The parent compound of this seris, (+/-)-15-deoxy-16alpha,beta-hydroxyprostaglandin E1 methyl ester (3), was found to be equipotent to the reference standard PGE1ME. Methylation at C-16 of 3 produced 8 which was found to be some 40 times more potent than PGE1. In sharp contrast, addition of two methyl groups to 3 at C15 or C17 markedly reduced the antisecretory action. The 16-ethyl analogue of 3 also showed reduced potency. Removal or epimerization of the C-11 hydroxy group of 8 reduced the activity. Likewise, hydrogenation or changing the stereochemistry of the 13,14 double bond from trans to cis decreased the activity. On the other hand, omega-homologation of 8 or the introduction of a cis-5,6 double bond did not affect the potency. From these studies, it appears that 8, 16, and 17 possess optimum gastric antisecretory effects in this series.

Animals↗
PubMed1979

Interobserver variation in the evaluation of radiologic changes of rheumatoid arthritis.

The variation between four radiologists in the evaluation of hand, wrist, and foot radiographs of rheumatoid arthritis was examined. The recognition of individual radiologic changes varied considerably as judged by the findings of the different observers. Erosion and joint space narrowing were interpreted more uniformly than soft tissue swelling and osteoporosis. When the radiographs were graded from 0 to 5 using standard reference radiographs, more than 90% of them were graded uniformly or with a difference of only one grade. The investigation has shown that when applying grading of rheumatoid arthritis according to standard reference radiographs, the interobserver variation is considerably less than when pure individual radiological changes of rheumatoid arhtritis are considered.

Adult↗
PubMed2026

Diagnostic accuracy of nuclear STAT6 immunohistochemistry for solitary fibrous tumour: a systematic review and meta-analysis.

Nuclear STAT6 immunohistochemistry is the diagnostic surrogate for the NAB2::STAT6 fusion of solitary fibrous tumour (SFT); its sensitivity is established, but specificity varies for unexamined reasons. This review quantified pooled accuracy and tested whether antibody clone and nuclear threshold govern specificity. PubMed, Scopus and Web of Science were searched to 29 June 2026 for studies reporting nuclear STAT6 immunohistochemistry against a reference standard (NAB2::STAT6 confirmation and/or expert consensus) in SFT and comparators, with extractable two-by-two data. Two reviewers screened, extracted data and applied QUADAS-2. A bivariate generalised linear mixed model gave summary sensitivity and specificity, and exploratory subgroup analysis and meta-regression tested antibody clone, anatomical site and reference-standard type. Twenty-three studies (1216 SFT and 4715 comparators) were included. Summary sensitivity was 98.7% (95% confidence interval 96.7-99.5) and specificity 99.1% (97.8-99.6); the diagnostic odds ratio was approximately 8656. The monoclonal YE361 subgroup (8 studies) reached specificity 99.9% (99.3-100), with one false positive among 861 comparators, versus 98.1% (96.0-99.1) for polyclonal and other antibodies. False positives concentrated in dedifferentiated liposarcoma and prostatic stromal tumours. Estimates were stable after removing studies at higher risk of bias (98.9%/99.1%) and on leave-one-out analysis; the Deeks test was non-significant (p = 0.08). Nuclear STAT6 immunohistochemistry is therefore highly sensitive and specific for SFT, and the residual specificity loss is structured and largely avoidable: the monoclonal YE361 read at a strict nuclear threshold is preferred, with MDM2 and CDK4 applied to exclude dedifferentiated liposarcoma when nuclear STAT6 is unexpectedly positive.

Humans↗
PubMedDate not supplied

Autorhythmometry: leads from single-sample medical check-ups toward a health science of time series.

Starting from the definition of health as given by the WHO, the authors emphasize that rhythms of biological variables should be taken into account if one is to arrive at a positive and individual definition of the concept of health. The evaluation of a single datum spot check of physiological functions does not permit to quantify health in dynamic terms whereas this may become possible when the rhythmic quality of these variables, according to a spectrum of characteristic frequencies, has been assessed. Rhythmometry provides for appropriate reference standards as regards both the population in general and the physical conditions of the same subject during certain spans in the (prospective) life history (spans selected according to consideration of risk and hence cost and benefit at a given age). The authors therefore stress the importance of rhythmometry, thanks to which the time course and other peculiarities of any biological phenomenon can be evaluated by obtaining serial measurements, objectively quantifying their characteristic features, and working out special models with the aid of computers. Of special interest, particularly for the evaluation of reference standards, is autorhythmometry (AR), to be used at least for certain variables. This is the method by which each subject studies himself, performing a certain number of measurements in the course of the day (or month or year) of his body temperature, blood pressure, cardiac rhythm, grip strength, etc. In AR, the subject takes an active part in the study of his condition of health and it has been shown that in the majority of cases these measurements are done with the utmost accuracy and precision, providing that the purpose of the operations to be performed has been adequately explained. The wide spread use of AR, during more or less extended periods in a lifetime, would permit the assessment of the normal situation for each individual and thus offer the possibility of diagnosing any disorder at its very beginning; it would thus be of great prophylactic value. The authors refer to the example of arterial blood pressure; widely different values for the normal levels can be found in the texts of different authors. They also show that a certain presure may be normal for a given subject at a certain time of day and be a sign of illness for another subject, or even for the same subject at a different ime. The authors suggest the introduction of AR in the curriculum of secondary schools and into the routine for outpatients and inpatients. This practice would increase the availability of information on public health at a lower cost. AR may be very usefully applied to chronotherapy: it is a well-known fact that there are rhythms of sensitivity and therefore rhythms of toxic as well as therapeutic effects for various drugs. These can be dove-tailed in such a way as to work out, for individual cases, a time for administration at which the therapeutic effect is at its maximum and the toxic one at its minimum...

Animals↗
PubMed2024

Evaluating culture-free targeted next-generation sequencing for diagnosing drug-resistant tuberculosis: a multicentre clinical study of two end-to-end commercial workflows.

BACKGROUND: Drug-resistant tuberculosis remains a major obstacle in ending the global tuberculosis epidemic. Deployment of molecular tools for comprehensive drug resistance profiling is imperative for successful detection and characterisation of tuberculosis drug resistance. We aimed to assess the diagnostic accuracy of a new class of molecular diagnostics for drug-resistant tuberculosis. METHODS: We conducted a prospective, cross-sectional, multicentre clinical evaluation of the performance of two targeted next-generation sequencing (tNGS) assays for drug-resistant tuberculosis at reference laboratories in three countries (Georgia, India, and South Africa) to assess diagnostic accuracy and index test failure rates. Eligible participants were aged 18 years or older, with molecularly confirmed pulmonary tuberculosis, and at risk for rifampicin-resistant tuberculosis. Sensitivity and specificity for both tNGS index tests (GenoScreen Deeplex Myc-TB and Oxford Nanopore Technologies [ONT] Tuberculosis Drug Resistance Test) were calculated for rifampicin, isoniazid, fluoroquinolones (moxifloxacin, levofloxacin), second line-injectables (amikacin, kanamycin, capreomycin), pyrazinamide, bedaquiline, linezolid, clofazimine, ethambutol, and streptomycin against a composite reference standard of phenotypic drug susceptibility testing and whole-genome sequencing. FINDINGS: Between April 1, 2021, and June 30, 2022, 832 individuals were invited to participate in the study, of whom 720 were included in the final analysis (212, 376, and 132 participants in Georgia, India, and South Africa, respectively). Of 720 clinical sediment samples evaluated, 658 (91%) and 684 (95%) produced complete or partial results on the GenoScreen and ONT tNGS workflows, respectively, with 593 (96%) and 603 (98%) of 616 smear-positive samples producing tNGS sequence data. Both workflows had sensitivities and specificities of more than 95% for rifampicin and isoniazid, and high accuracy for fluoroquinolones (sensitivity approximately ≥94%) and second line-injectables (sensitivity 80%) compared with the composite reference standard. Importantly, these assays also detected mutations associated with resistance to critical new and repurposed drugs (bedaquiline, linezolid) not currently detectable by any other WHO-recommended rapid diagnostics on the market. We note that the current format of assays have low sensitivity (≤50%) for linezolid and more work on mutations associated with drug resistance is needed. INTERPRETATION: This multicentre evaluation demonstrates that culture-free tNGS can provide accurate sequencing results for detection and characterisation of drug resistance from Mycobacterium tuberculosis clinical sediment samples for timely, comprehensive profiling of drug-resistant tuberculosis. FUNDING: Unitaid.

Humans↗
PubMed2026

Performance of AI-Based Screening Tools for Obstructive Sleep Apnea Across Apnea-Hypopnea Index Thresholds: Systematic Review and Meta-Analysis.

BACKGROUND: Obstructive sleep apnea (OSA) is highly prevalent but remains substantially underdiagnosed. Polysomnography (PSG) is the reference standard, but its cost and limited availability constrain large-scale case identification. AI-based screening tools may support risk stratification and referral prioritization, but their diagnostic accuracy across apnea-hypopnea index (AHI) thresholds remains uncertain. OBJECTIVE: This review aimed to systematically evaluate the diagnostic accuracy of AI-based OSA screening tools at AHI thresholds of ≥5, ≥15, and ≥30 events/hour, with emphasis on models using non-PSG-derived inputs. METHODS: PubMed, Embase, Scopus, and Web of Science were searched for studies published from January 1, 2016, to May 3, 2026. Eligible studies included adults evaluated for suspected OSA or recruited from population-based cohorts, assessed AI-based models intended or interpretable for OSA screening, risk prediction, or screening-oriented severity classification, used PSG as the reference standard, and reported sufficient data to construct or reconstruct 2×2 contingency tables. Diagnostic accuracy was synthesized separately by AHI threshold and input source using bivariate random-effects models, with 95% CIs and prediction intervals (PIs). Risk of bias and certainty of evidence were assessed using QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies 2) and GRADE (Grading of Recommendations Assessment, Development, and Evaluation), respectively. RESULTS: A total of 60 studies were included, of which 47 contributed data to the meta-analysis. At AHI thresholds of ≥5, ≥15, and ≥30 events/hour, pooled sensitivities were 0.94 (95% CI 0.92-0.96; 95% PI 0.71-0.99), 0.87 (95% CI 0.84-0.89; 95% PI 0.66-0.96), and 0.83 (95% CI 0.79-0.87; 95% PI 0.61-0.94), respectively; the corresponding specificities were 0.77 (95% CI 0.69-0.84; 95% PI 0.30-0.96), 0.81 (95% CI 0.75-0.85; 95% PI 0.39-0.96), and 0.91 (95% CI 0.87-0.94; 95% PI 0.55-0.99), respectively. The corresponding areas under the summary receiver operating characteristic curves were 0.943, 0.907, and 0.920. For non-PSG-derived tools, sensitivities were 0.92, 0.85, and 0.81, and specificities were 0.70, 0.74, and 0.85 at the 3 thresholds, respectively. For PSG-derived models, sensitivities were 0.96, 0.90, and 0.85, and specificities were 0.82, 0.88, and 0.96, respectively. Exploratory subgroup analyses suggested performance variation across selected study and model characteristics, including region, algorithmic framework, data source, and validation method. CONCLUSIONS: AI-based tools showed generally favorable screening performance for OSA across clinically relevant AHI thresholds, although wide PIs suggest variable performance across future comparable populations and settings. By synthesizing diagnostic accuracy across 3 AHI thresholds and distinguishing non-PSG-derived from PSG-derived models, this review extends previous broad or modality-specific reviews and offers a clinically interpretable, pathway-specific basis for linking model performance to intended use. The findings may clarify potential roles for non-PSG-derived tools in front-end screening and referral prioritization and for PSG-derived models in reduced-channel assessment and sleep-laboratory workflow support. Given substantial heterogeneity, limited external validation, and low or very low certainty of evidence, prospective validation is needed before routine implementation.

Humans↗
PubMed1976

Study of genetic relationships among marine species of the genera Beneckea and Photobacterium by means of in vitro DNA/DNA hybridization.

Strains representative of species of the marine genera Beneckea and Photobacterium were used as reference standards in in vitro DNA/DNA competition experiments. Within a given species, strains were found to be related by over 80% competition. (Competition was defined as the amount of radioactive DNA displaced by heterologous DNA relative to the amount displaced by homologous DNA.) On the basis of interspecies competition values (expressed as averages), the following groupings could be made: 1. "Photobacterium" fischeri was related to strain ATCC 15382 by a competition of 38% and was distinct from all the other strains tested (competition less than or equal to 11%). 2. The genus Photobacterium consisted of 3 species, P.phosphoreum, P.leiognathi, and a newly designated species, P.angustum (composed of non-luminous strains). The latter species was found to be related to P.leiognathi and P.phosphoreum by 56 and 28% competition, respectively, while P.phosphoreum was related to P.leiognathi by 29%. 3. In the genus Beneckea, 65% competition was detected between B.harveyi and B.campbellii as well as between B.parahaemolytica and B.alginolytica. These pairs of species were related to each other by 51-58% and to B.natriegens by 34-56% competition. A newly designated pathogenic species, B.vulnifica, appeared to have a low but significant relationship to all the above mentioned species of Beneckea. 4. Two biotypes, related by 68% competition, were recognized in the species B.splendida. Similarly, B.pelagia was found to consist of 2 biotypes related by a competition of 67%. The competition values between these species were 38-40%. 5. B.nereida, B.nigrapulchrituda, and "Vibrio" anguillarum had competition values less than or equal to 30% to each other as well as to other species of Beneckea. 6. With Vibrio cholerae as the reference standard, V.albensis was found to be related by a competition of 82%, while V.proteus and V.metschnikovii had competition values of 22 and 12%, respectively. These results suggested that V.albensis should be synonymized with V.cholerae, while the latter two organisms should remain distinct from this species. V.cholerae as well as the other terrestrial organisms tested did not appear to be significantly related to any of the marine strains (competition values less than or equal to 27%). The speciation derived from the results of the DNA/DNA competition experiments was compared to previous speciation based on phenotypic similarities.

DNA, Bacterial↗
PubMed1976

The serology of Pseudomonas aeruginosa analysed by means of quantitative immunoelectrophoretic methods. V. Thermostability, resistance to degradation by plasmin activity and storage conditions of a polyvalent P. aeruginosa reference standard-antigen.

The stability of a polyvalent Pseudomonas aeruginosa antigen (St-Ag) was analysed under different experimental conditions by quantitative immunoelectrophoretic methods. St-Ag did not undergo proteolytic degradation by plasmin which is present in the corresponding polyvalent rabbit antiserum (St-Ab) against St-Ag. Storage at -30 degrees C for up to 4 years caused no qualitative changes in St-Ag and, after 1 year, only minor quantitative changes could be revealed. Repeated thawing and freezing caused no changes in St-Ag whereas storage at 4 degrees C, or at room temperature, caused gradual degradation of most of the antigens of St-Ag, beginning after 1 week. Heating up to 40 degrees C for 2 min did not change St-Ag, but heating for longer periods of time or at higher temperatures gradually destroyed most of the antigens of St-Ag. The most thermostable antigen in St-Ag was number 37 which is related to the group specific O antigens.

Antigens, Bacterial↗
PubMed1975

The serology of Pseudomonas aeruginosa analysed by means of quantitative immunoelectrophoretic methods. III. Reproducibility of a polyvalent P. aeruginosa reference standard-antigen.

The reproducibility of a polyvalent Pseudomonas aeruginosa antigen (St-Ag) composed of a mixture of antigens from 4 O groups of this bacterium has been studied. Ten batches of St-Ag were produced, and each of these and each of the 10 batches of antigens from the 4 strains of P. aeruginosa were compared with St-Ag batch 1 by means of quantitative immunoelectrophoretic methods and a polyvalent antiserum (St-Ab) raised against St-Ag. Fifty-three of the 55 antigens of St-Ag were stable and could be reproduced with reasonable precision in all 10 batches, and 3 of the 4 strains of P. aeruginosa were stable in antigen composition in all batches. One of the strains (0-5A) had lost 2 antigens in the last 5 batches, and the concentrations of 7 other antigens were simultaneously changed, reflecting a smooth-rough dissociation. The disappearance of the 2 antigens in the latest 5 batches of 0-5A was also reflected in similar changes in the antigen composition of the latest 5 batches of St-Ag.

Antigens, Bacterial↗
PubMed1979

Lactate-to-pyruvate or pyruvate-to-lactate assay for lactate dehydrogenase: a re-examination.

The pyruvate-to-lactate assay for determining lactate dehydrogenase (EC 1.1.1.27) can now yield linearity equal to or better than that obtained by the lactate-to-pyruvate assay. In addition, there are significant advantages to the pyruvate-to-lactate reaction: (a) a greater change in absorbance per unit time, which allows more accurate spectrophotometric readout; (b) lower reactant concentrations are required, which substantially reduces the cost per assay; (c) solid reagents are used to prepare the assay solution; and (d) reagent solutions are more stable. However, impurities present in commercial NADH preparations may substantially affect measured lactated dehydrogenase activities; therefore, a Standard Reference Material for NADH is being developed for issuance by the National Bureau of Standards.

L-Lactate Dehydrogenase↗
PubMed1979

Ossification of femoral head in infancy. I. Normal standards.

Observations made in 455 Malmö infants with assumedly normal ossification of the femoral heads were used for establishing reference standards for the age at onset of the ossification and for the size of the ossification centers according to sex and age.

Age Factors↗
PubMed1976

Energy-dispersive x-ray fluorescence spectroscopy and inductively coupled plasma emission spectrometry evaluated for multielement analysis in complex biological matrices.

Energy-dispersive x-ray spectroscopy and inductively coupled plasma emission spectrometry were evaluated as methods for routine multielement analysis of biological material. Standard samples included Standard Reference Materials (National Bureau of Standards), compounded mixtures, and supplements that provided a wide range of elemental concentrations for analysis. Elements included in this study were Zn, Pb, Ni, Mn, Fe, Mg, Cu, Ca, As, Se, Br, Rb, and Sr. Standards were analyzed as unknowns by participating laboratories. The two methods were evaluated for sensitivity, precision, and accuracy, and the results compared to those obtained for atomic absorption spectrometric analysis of identical standard unknowns. Both methods compared favorably and both were determined to be highly reliable for such an application. Advantages and disadvantages of each method are compared and discussed.

Animals↗
PubMed1978

A simple and rapid technic for radioimmunoassay and calculation of plasma steroid concentrations.

A simple RIA technic for plasma steroids is described: Extraction residues or reference standards are dissolved in 20 microliter ethyl alcohol, or 20 microliter of alcoholic plasma extracts are given directly into RIA tubes; 500 microliter tracer solution, containing a known tracer mass, and, after mixing, 500 microliter antiserum solution or buffer solution are added, followed by 20 min incubation at room temperature and 20 min standing in an ice bath. Free from bound activity is separated by charcoal coated florisil or silicagel. Plasma steroid levels are calculated by a simple equation. An immunologic equivalent to the tracer mass present in the reaction mixture serves as reference value. Drawing of standard curves is not necessary for every assay. The linear transformation used here allows the number of reference standards to be reduced. So also single samples can be analyzed with relatively low effort.

Estradiol↗
PubMed1979

An improved gas-liquid chromatographic procedure for the determination of amitriptyline and nortriptyline levels in plasma using nitrogen-sensitive detectors.

An improved gas-liquid chromatographic procedure for the plasma level determination of amitriptyline and nortriptyline using nitrogen-sensitive detectors is described. Derivatization of the secondary amines using trifluoroacetic anhydride greatly improves the response and reproducibility of the assay. Plasma samples containing as little as 5 ng/ml of amitriptyline and nortriptyline can be assayed precisely and reproducibly, using protriptyline as internal reference standard.

Amitriptyline↗