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To date, no study has focused on Uvaria macrophylla leaves with various traditional efficiencies. This paper therefore applied a database affinity ultra-high-performance liquid chromatography with quadrupole Orbitrap tandem mass spectrometry (UHPLC-Q-Orbitrap-MS/MS) strategy to analyze the lyophilized aqueous extract of U. macrophylla leaves. Through database comparison and MS fragment elucidation, this study has putatively identified 41 constituents belonging to flavonoid, phenolic acid, steroid, and saccharide natural product classifications. Significantly, four groups of isomers (liquiritigenin vs. isoliquiritigenin vs. pinocembrin; oroxylin A vs. wogonin vs. galangin 3-methyl ether; isoquercitrin vs. hyperoside; protocatechuic acid vs. 2,5-dihydroxybenzoic acid) have been successfully distinguished from each other. All of 41 constituents were then subjected to a quantitative analysis based on linear regression equation established by the above UHPLC-Q-Orbitrap-MS/MS strategy and an ABTS+•-scavenging antioxidant assay. Finally, the chemical content was multiplied by the corresponding ABTS+•-scavenging percentage to calculate the antioxidant contribution. It was shown that the chemical contents of 41 constituents varied from 0.003 ± 0.000 to 14.418 ± 1.041 mg/g, and gallic acid showed the highest antioxidant contribution. Gallic acid is considered as a suitable antioxidant quality-marker (Q-marker) of U. macrophylla leaves. These findings have scientific implications for the resource development and quality control of U. macrophylla leaves. [ABSTRACT FROM AUTHOR]

Objective: We aimed to establish a practical diagnostic index for Lewy body diseases (LBD), such as Parkinson's disease and dementia, with Lewy bodies in outpatient settings and criteria for exempting patients from late imaging. Methods: We acquired early and late 123I-metaiodobenzylguanidine (MIBG) images from 108 consecutive patients with suspected LBD and standardized heart-to-mediastinum (H/M) ratios for collimator conditions. Exclusions included young-onset Parkinson's disease (age < 50 years) and genetic transthyretin-type amyloidosis. We developed logistic models incorporating H/M ratios with or without age (n = 92). The sympathetic MIBG index for LBD (SMILe index), categorized LBD likelihood from 0 (lowest) to 1 (highest). Diagnostic accuracy was assessed as the area under the receiver operating characteristic (ROC) curve (AUC). The characteristics of the new index were compared with H/M ratios. The need for late imaging was explored using the SMILe index. Results: Early or late SMILe indexes using a single H/M ratio variable discriminated LBD from non-LBD. The AUC values for early and late SMILe indexes were 0.880 and 0.894 (p < 0.0001 for both), identical to those for early and late H/M ratios. The sensitivity and the specificity of early SMILe indexes with a 0.5 threshold were 76% and 90%, achieving accuracy of accuracy 86%. Similarly, the late SMILe index demonstrated a sensitivity of 76% and specificity of 87%, with an accuracy of 84%. Early SMILe indexes < 0.3 or > 0.7 (representing 84% patients) indicated a diagnosis without a late MIBG study. Conclusion: The 123I-MIBG-derived SMILe indexes provide likelihood of LBD, and those with a 50% threshold demonstrated optimal diagnostic accuracy for LBD. The index values of either < 0.3 or > 0.7 accurately selected patients who do not need late imaging. [ABSTRACT FROM AUTHOR]

Background: Cardiac positron emission tomography (PET) offers non-invasive assessment of perfusion and left ventricular (LV) function from a single dynamic scan. However, no prior assessment of mitral regurgitation severity by PET has been presented. Application of indicator dilution techniques and gated image analyses to PET data enables calculation of forward stroke volume and total LV stroke volume. We aimed to evaluate a combination of these methods for measurement of regurgitant volume (RegVol) and fraction (RegF) using dynamic 15O-water and 11C-acetate PET in comparison to cardiovascular magnetic resonance (CMR). Results: Twenty-one patients with severe primary mitral valve regurgitation underwent same-day dynamic PET examinations (15O-water and 11C-acetate) and CMR. PET data were reconstructed into dynamic series with short time frames during the first pass, gated 15O-water blood pool images, and gated 11C-acetate myocardial uptake images. PET-based RegVol and RegF correlated strongly with CMR (RegVol: 15O-water r = 0.94, 11C-acetate r = 0.91 and RegF: 15O-water r = 0.88, 11C-acetate r = 0.84, p < 0.001). A systematic underestimation (bias) was found for PET (RegVol: 15O-water − 11 ± 13 mL, p = 0.002, 11C-acetate − 28 ± 16 mL, p < 0.001 and RegF: 15O-water − 4 ± 6%, p = 0.01, 11C-acetate − 10 ± 7%, p < 0.001). PET measurements in patients were compared to healthy volunteers (n = 18). Mean RegVol and RegF was significantly lower in healthy volunteers compared to patients for both tracers. The accuracy of diagnosing moderately elevated regurgitant volume (> 30mL) was 95% for 15O-water and 92% for 11C-acetate. Conclusions: LV regurgitation severity quantified using cardiac PET correlated with CMR and showed high accuracy for discriminating patients from healthy volunteers. [ABSTRACT FROM AUTHOR]

A quantitative gas chromatography mass spectrometry (GC/MS) method was developed for delta‐9‐tetrahydrocannabinol (delta‐9‐THC), delta‐8‐tetrahydrocannabinol (delta‐8‐THC), tetrahydrocannabinolic acid (THCA), and cannabidiol (CBD) in matrices including plant material, liquids and oils, waxes, edibles, and bath and body products. Samples were prepared by homogenization, extraction of the cannabinoids into solvent, liquid/liquid extraction, and derivatization. The GC/MS method was validated from 0.15% to 5.00% (weight basis) to encompass the 0.3% legal distinction between hemp and marijuana. Validation was performed assessing imprecision/bias, calibration model, recovery, interferences, limit of detection, matrix matching, carryover, accuracy, and an assessment of CBD conversion to delta‐9‐THC. The calibration curves were quadratic weighted 1/x with r2 > 0.990. The method had a detection limit of 0.075% in plant material for each analyte. Analyte recovery was greater than 70% in plant material. Carryover was not observed up to concentrations equivalent to 100% analyte, and no forensically significant conversion of CBD to delta‐9‐THC was observed. One cannabinoid isomer, 9(R)‐delta‐7‐tetrahydrocannabinol (9(R)‐delta‐7‐THC), was determined to interfere with the quantitation of delta‐9‐THC, but could be differentiated based on mass spectrum. The method was determined to be suitable for quantitation of delta‐9‐THC, delta‐8‐THC, delta‐9‐THCA, and CBD and was able to differentiate hemp samples from marijuana samples. [ABSTRACT FROM AUTHOR]

Abstract Background Cardiac positron emission tomography (PET) offers non-invasive assessment of perfusion and left ventricular (LV) function from a single dynamic scan. However, no prior assessment of mitral regurgitation severity by PET has been presented. Application of indicator dilution techniques and gated image analyses to PET data enables calculation of forward stroke volume and total LV stroke volume. We aimed to evaluate a combination of these methods for measurement of regurgitant volume (RegVol) and fraction (RegF) using dynamic 15O-water and 11C-acetate PET in comparison to cardiovascular magnetic resonance (CMR). Results Twenty-one patients with severe primary mitral valve regurgitation underwent same-day dynamic PET examinations (15O-water and 11C-acetate) and CMR. PET data were reconstructed into dynamic series with short time frames during the first pass, gated 15O-water blood pool images, and gated 11C-acetate myocardial uptake images. PET-based RegVol and RegF correlated strongly with CMR (RegVol: 15O-water r = 0.94, 11C-acetate r = 0.91 and RegF: 15O-water r = 0.88, 11C-acetate r = 0.84, p 30mL) was 95% for 15O-water and 92% for 11C-acetate. Conclusions LV regurgitation severity quantified using cardiac PET correlated with CMR and showed high accuracy for discriminating patients from healthy volunteers.

Introduction of meta-aramid units into poly (p-phenylene terephthalamide) (PPTA) allows regulation of its crystallization and processing properties, therefore, quantitation of the meta units in PPTA is of practical importance. In this paper, blends of PPTA with poly (m-phenylene isophthalamide) (PMIA) were prepared and analyzed by infrared and Raman spectroscopies. In the infrared spectra, it was found that the absorption band at 659 cm−1 attributed to C—H in-plane wagging vibration of the m-disubstituted benzene ring can be utilized for quantitative analysis of PMIA, the intensity of which exhibited good linear relationship with PMIA content, allowing detection of meta units of 2. 0% (mass percent) and above. In the Raman spectra of the blends, the breathing vibration of the meta-disubstituted benzene ring at 1002 cm−1 characteristic of PMIA was found to exhibit an intensity proportional to its content with excellent linear correlation, which enabled detection of meta units of a low content of 0. 25% (mass percent）. In conclusion, the Raman method is more accurate with a lower detection limit, and therefore is superior to the IR method for quantitation of meta units in para-aramids. [ABSTRACT FROM AUTHOR]

The study of glycoproteomics presents a set of unique challenges, primarily due to the low abundance of glycopeptides and their intricate heterogeneity, which is specific to each site. Glycoproteins play a crucial role in numerous biological functions, including cell signaling, adhesion, and intercellular communication, and are increasingly recognized as vital markers in the diagnosis and study of various diseases. Consequently, a quantitative approach to glycopeptide research is essential. One effective strategy to address this need is the use of multiplex glycopeptide labeling. By harnessing the synergies of 15N metabolic labeling via the isotopic detection of amino sugars with glutamine (IDAWG) technique for glycan parts and tandem mass tag (TMT)pro labeling for peptide backbones, we have developed a method that allows for the accurate quantification and comparison of multiple samples simultaneously. The adoption of the liquid chromatography-synchronous precursor selection (LC-SPS-MS3) technique minimizes fragmentation interference, enhancing data reliability, as shown by a 97% TMT labeling efficiency. This method allows for detailed, high-throughput analysis of 32 diverse samples from 231BR cell lines, using both 14N and 15N glycopeptides at a 1:1 ratio. A key component of our methodology was the precise correction for isotope and TMTpro distortions, significantly improving quantification accuracy to less than 5% distortion. This breakthrough enhances the efficiency and accuracy of glycoproteomic studies, increasing our understanding of glycoproteins in health and disease. Its applicability to various cancer cell types sets a new standard in quantitative glycoproteomics, enabling deeper investigation into glycopeptide profiles. [ABSTRACT FROM AUTHOR]

During chronic hepatitis B virus (HBV) infection, the seroclearance of hepatitis B e antigen (HBeAg) is an important event and a significant surrogate endpoint of all current therapeutic strategies. The prediction of HBeAg seroclearance can help assess the benefits of therapy in patients during or before therapy initiation. The quantitation of HBV core antibodies (qAnti-HBc) is a new non-invasive biomarker for solving multiple diagnostic dilemmas. A systematic review and meta-analysis of studies that measured qAnti-HBc in patients who achieved HBeAg seroclearance were performed through PubMed, Web of Science (WoS) and SCOPUS electronic database searches. Nineteen articles were included in the systematic review, comprising 3434 chronically infected patients (1014 with and 2420 without HBeAg seroclearance). Sixteen publications with data regarding qAnti-HBc levels were included in the meta-analysis. The baseline level of qAnti-HBc antibodies was significantly higher in patients with than without HBeAg seroclearance (SMD = 0.88, 95%CI SMD = 0.56–1.2, p < 0.001). The same conclusion was reached for patients originating from Asia (SMD = 0.94, 95%CI SMD = 0.55–1.33) and for the qAnti-HBc antibodies among adult HBV patients with therapy-induced HBeAg seroclearance (SMD = 0.90, 95%CI SMD = 0.54–1.25, p < 0.001). The systematic review and meta-analysis provide evidence of the role of qAnti-HBc as a promising biomarker for predicting HBeAg seroclearance in chronically infected patients. [ABSTRACT FROM AUTHOR]

A simple, rapid and accurate titrimetric procedure using potassium hydrogenperoxymonosulphate have been developed for the semi-micro determination of sodium metamizole in pure form and in tablets. The proposed method is based on the oxidation of bisulfite ions formed as a result of acid hydrolysis of sodium metamizole by known excess of the potassium hydrogenperoxomonosulphate with the following determination of the residual oxidant by iodometric titration. The optimum reactions conditions and other analytical parameters are evaluated. The influence of the substrates commonly employed as excipients with sodium metamizole has been studied. Statistical comparison of the results with those of an official method shows excellent agreement and indicates no significant difference in precision. RSD ≤ 1.49%; (δ =0.49 - 0.84%). LOQ=0.01 mg. [ABSTRACT FROM AUTHOR]

Background and purpose: Ketoconazole is limited to its conditioned oral use due to hepatic toxicity. Its ocular eye drop administration may be an option for mycotic keratitis treatment. Therefore, it is necessary to explore its pharmacokinetic and metabolic profile via topical ocular administration. Experimental approach: Nine rats were dosed at 300 µg/rat via topical ocular administration, and sacrificed at 5, 30, and 120 min with 3 rats/timepoint. Plasma, cornea, retina, and vitreous humour samples were collected, processed, and analysed. Key results: Ketoconazole was quantified with a mean peak plasma concentration of 445 ng/mL at 5 min post-dose. In the rat ocular tissue, the mean ketoconazole concentration at 5 min post-dose was 423 μg/g in the cornea, 4.96 μg/g in the retina, and 1.19 μg/g in the vitreous humour, respectively. The mean ketoconazole concentration in each matrix decreased from 5 to 120 min. The mean ketoconazole concentration at 120 min was 38.4 ng/mL in plasma, and 8.36, 0.0944, and 0.116 μg/g in the cornea, retina, and vitreous humour, respectively. Pooled plasma, cornea, retina, and vitreous humour homogenates were used for metabolite identification. Nine metabolites were identified in rat plasma, and O-dealkylated metabolite (M3) and dehydrogenated metabolite (M11) were the top two, accounting for 5.0 and 5.8 % of the relative mass abundance. The metabolic pathways were O-dealkylation, mono-oxygenation, and dehydrogenation. Eleven metabolites were identified in the rat cornea, and two metabolites were identified in the rat retina and vitreous humour, respectively. The O-dealkylated and hydrogenated metabolite (M2) was a dominant metabolite in the cornea, retina, and vitreous humour, while M3 and M11 were the dominant metabolites in plasma. Conclusion: Ketoconazole was a dominant component (≥ 98.5 %) in the cornea, retina, and vitreous humour, having higher concentrations in cornea than in plasma. M2 was identified as a dominant metabolite (1.1 - 1.2 %) in the cornea, retina, while M3 (5.0 %) and M11 (5.8 %) were identified as dominant metabolites in the plasma.

In this study, glycerin was used instead of traditional solvents such as methanol in combination with ultrasonic treatment for the high-efficiency extraction of multiple chemical components from tea. Furthermore, a quantitative analytical method for 130 chemical components belonging to seven classes in tea and its by-products was developed using ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry (UPLC-QQQ-MS/MS). The results showed that the extraction efficiency of glycerol was comparable to that of methanol and ethanol, and significantly better than that of water. The developed method had high sensitivity (limit of detection of 0.000 1-4.332 1 mg/kg) and accuracy (recoveries of 80.10%–121.12%). Appling this method to real samples, the content of each component varied greatly among different types of tea and by-products. Compared with tea samples, tea residue, a tea by-product, contained higher contents of caffeine, catechin and theanine, indicating the potential value of this by-product.

Liquid-state Overhauser Dynamic Nuclear Polarization (ODNP) is an emerging technique, aimed at shortening NMR experiment times. It achieves this by increasing the otherwise poor nuclear polarization at room temperature, by polarization transfer from excited electron spins. The present work explores two ideas, aimed at achieving the optimal signal-to-noise per time unit for a given system, and quantitation of spectra showing a large disparity in ODNP enhancements at high magnetic fields (≥ 9.4 T). Both of these ideas are predicated on, perhaps counterintuitively, not allowing full dynamic nuclear polarization to build up, either by rapid rf pulsing, or gating of the microwave irradiation.

Tea leaves are rich in diverse bioactive compounds. The tea accession TRI 2043 is unique due to its pigmented leaves caused by anthocyanins, clonal origin, resistance to blister blight disease, and high pubescence density. Because of its peculiarity, TRI 2043 is used to produce high-quality silver tip tea, a premium type of tea that commands high prices. This study was carried out to clarify and elucidate the types of anthocyanins in this particular accession. Four different anthocyanin species were identified and quantitated as cyanidin-3-O-β-d-galactoside and delphinidin-3-O-β-d-galactoside equivalents for leaf blades and stems of the cultivar TRI 2043. The characterization was performed by comparison with commercially available reference substances and further confirmed using ion mobility high-resolution time-of-flight-mass spectrometry (IMS-HRTOF-MS). Quantitation was carried out using ultra-high-performance liquid chromatography ultraviolet–visible detection (UHPLC-UV-vis) with cyanidin-3-O-β-d-glucoside as an internal standard. E- and Z-geometric isomers of 6-p-coumaroyl derivates of delphinidin and cyanidin-3-O-β-d-galactopyranosides were observed, and collision cross section (CCS) values were determined for all four different anthocyanidin species. The content of anthocyanins in leaf blades of cultivar TRI 2043 was 856.32 ± 41.56 µg/g dry weight, with cyanidin being the more abundant anthocyanin (69.8%). Conversely, the stem material contained an anthocyanin amount of 459.5 ± 44.7 µg/g dry weight, with a higher content of delphinidin (69.6%). In summary, an enrichment strategy using analytical membrane chromatography was established to fully elucidate and quantify the anthocyanin profile of plant samples such as the special tea variety TRI 2043. [ABSTRACT FROM AUTHOR]

Surface‐enhanced Raman scattering nanoparticles (SERS NPs) offer powerful optical contrast features for imaging assays. Their gold core enhances the inelastic scattering cross section, allowing highly sensitive and rapid detection, and their characteristic sets of narrow spectral bands give them unsurpassed multiplexing capabilities. Multiplexed hyperspectral images are commonly unmixed using a compensation matrix of reference spectra to produce quantitative image channels illustrating the distribution of each material. It is these unmixed channels that are fit for interpretation from assays utilizing SERS NP contrast agents. Some factors that may impact SERS NP quantitative and dynamic range capabilities may include endogenous background heterogeneity, the ability of unmixing algorithms to account for signal variances, and linear system conditioning imposed by contrast agent signals. We report on hyperspectral Raman imaging of mixtures of SERS NPs from an expanded library of contrast agents. We study increasing plexity and varying degrees of system conditioning as inputs to a diverse set of classical, non‐negatively constrained, and regularized regression algorithms to investigate which signal features and unmixing methods deliver the most promising quantitation performance with the least error. Raman imaging of SERS NP mixtures is performed on controlled substrates and representative biological specimens, and experimental results are compared against ground truth data. We evaluate spectral fitting fidelity, quantitation, and specificity correlations with system conditioning. Spectral unmixing with a regularized hybrid of least squares regression with principal component analysis (HLP) algorithm approximated spectra with 3.5× better fitting fidelity and 3× better quantitation robustness with tissue background compared with simpler unmixing routines. [ABSTRACT FROM AUTHOR]

This study presents the development and validation of a novel capillary zone electrophoresis method for the precise determination of glatiramer acetate and its amino acid constituents. A 120 mmol dm−3 phosphoric acid solution adjusted to pH 1.9 with Tris, supplemented with 20 mmol dm−3 triethylamine to achieve a final of pH 2.1, resulted in a repeatable analysis of glatiramer acetate. The method demonstrated a limit of detection and quantification of 39.2 µg cm−3 and 130.7 µg cm−3, respectively. This method allows for the rapid control of glatiramer acetate-based pharmaceuticals and distinguishes glatiramer acetate from the amino acids used in its synthesis. [ABSTRACT FROM AUTHOR]

AbstractThe just-ended COVID-19 pandemic and the looming global aging remind us that we need to be prepared for the shortage of doctors, which might become an urgent medical crisis in the future. Medical AI could relieve this urgency and sometimes perform better than human doctors; however, people are reluctant to trust medical AI because of algorithm aversion. Although several factors that can minimize algorithm aversion have been identified, they are not effective enough to promote medical AI as people’s first choice. Therefore, inspired by the direct and indirect information model of trust and media equation hypothesis, this research explored a new method to minimize aversion to medical AI by highlighting its social attributes. In 3 between-subject studies, a medical AI system’s direct information (i.e., transparency and quantitation of the decision-making process (DMP)) and indirect information (i.e., social proof) were manipulated. Study 1 (N = 193) and 2 (N = 429) showed that transparency of DMP and social proof increased trust in AI, but did not affect trust in human doctors. Social proof jointly affected trust in AI with non-quantitative DMP but not quantitative DMP. Study 3 (N = 184) further revealed the joint effect of the transparent non-quantitative DMP and near-perfect social proof, which could minimize algorithm aversion. These results extended the direct-indirect information model in interpersonal trust, revealed conditional media equation in human-AI trust, and offered practical implications for medical AI interface design. [ABSTRACT FROM AUTHOR]

The present review encompasses various applications of multivariate curve resolution- alternating least squares (MCR-ALS) as a promising data handling, which is issued by analytical techniques in pharmaceutics. It involves different sections starting from a concise theory of MCR-ALS and four detailed applications in drugs analysis. Dissolution, stability, polymorphism, and quantification are the main four detailed applications. The data generated by analytical techniques associated with MCR-ALS deals accurately with different challenges compared to other chemometric tools. For each reviewed purpose, it was explained how MCR-ALS was applied and detailed information was given. Different approaches were introduced to overcome challenges that limit the use of MCR-ALS efficiently in pharmaceutical mixture were also discussed. [Display omitted] • Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) is a promising data handling tool for pharmaceutical analysis. • MCR-ALS can be used for various purposes, including drug dissolution, stability, polymorphism, and quantification studies. • MCR-ALS allows for accurate handling of matrix effects in pharmaceutical analysis. • Augmented matrix and correlation constraint approaches can be used to improve the efficiency of MCR-ALS in pharmaceutical analysis. • Different analytical techniques can be combined with MCR-ALS to achieve different purposes in drug analysis. [ABSTRACT FROM AUTHOR]

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Background: Coffee contains a plethora of constituents with some of them being especially important either due to their physiological effects or as quality markers. As quantitative proton nuclear magnetic resonance spectroscopy (1H‐NMR) has been established as a fast and reliable analytical tool its application was evaluated for the simultaneous quantitation of lactic acid, acetic acid, formic acid, caffeine, caffeoylquinic acid (CQA) isomers, N‐methylpyridinium, trigonelline, and 5‐hydroxymethylfurfural (HMF) in aqueous extracts of roasted Coffea arabica samples. Results: Simultaneous quantitative determination was achieved by an automated analysis based on the PULCON methodology (pulse length‐based concentration determination). The method was validated regarding linearity, accuracy, precision, limit of detection (LOD), and limit of quantitation (LOQ). Recovery rates were between 76% (CQA) and 116% (HMF), and precision was between 1.7% (caffeine) and 10.3% (HMF). The LOD varied between 0.06 g/kg (HMF) and 1.35 g/kg (caffeine and CQA), with the LOQ being between 0.22 g/kg (HMF) and 4.87 g/kg (CQA). To verify the results of the 1H‐NMR method, caffeine, trigonelline, HMF, 3‐CQA, 4‐CQA, and 5‐CQA were additionally quantitated by HPLC‐DAD and the results were compared. The described 1H‐NMR method was additionally applied to coffee samples that contained different coffee defects. Results showed only slight changes in the concentrations of the analytes by adding defective beans to defect‐free coffee. Discussion: The developed 1H‐NMR approach was proven to be fast (30 min), reliable, and precise. Thus, it is well suited to analyze several coffee constituents of interest in a large number of samples in, for example, quality control. [ABSTRACT FROM AUTHOR]

The analytical method for detecting and quantifying micro and nanoplastics (MNPs) using Pyrolysis-Gas Chromatography-Mass Spectrometry (Py-GC-MS) is evolving and continuously refined. The requirement for accurate analytical methods faces challenges during method validation due to the scarcity of relevant reference materials. Additionally, the wide array of polymer types and their diverse characteristics further complicate this validation process. This study evaluated the impact of using diverse polystyrene (PS) standards with different molecular weights, polydispersity indexes, tacticity, endcapping, and chain branching, on quantifying the mass concentration of PS in various products. The results for the PS-based products showed inconsistencies across different standards, indicating that the measurements for a single product varied substantially when different polystyrene (PS) standards were applied. The influence of sample quantity on pyrolysis revealed differences in the ratios of pyrolysis products among various PS standards and different sample amounts. This research emphasizes the complexities involved in the precise quantification of polymers using Py-GC-MS. It provides valuable insights crucial for quantitative MNP analysis, highlighting the need for refined calibration strategies and standardised reference materials to improve the reliability of the MNP analysis method.

Objectives: Antibodies to gp210 and sp100 are specific and unique anti-nuclear autoantibodies (ANAs) associated with primary biliary cholangitis (PBC). Importantly the presence of anti-gp210 and anti-sp100 responses is indicative of poor clinical outcomes. However, the utility of measuring titers of these antibodies remains unclear. Materials and methods: Using the in-house purified gp210 (HSA108-C18) and sp100 (amino acid position 296–386), we quantitatively measured serum autoantibodies to gp210 and sp100 using chemiluminescence immunoassay (CLIA) in a very large cohort of 390 patients with PBC, including 259 cases with no prior ursodesoxycholic acid (UDCA) treatment and 131 cases with UDCA treatment. We also analyzed serial changes in anti-gp210 and anti-sp100 levels in 245 sequential samples from 88 patients. Results: In our cross-sectional analysis, we detected anti-gp210 immunoglobulin G (IgG) and anti-sp100 IgG autoantibodies in 129 out of 390 (33.1%) and 80 out of 390 (20.5%) PBC patients, respectively. Multivariate analysis revealed that serum IgG (st.β = 0.35, P = 0.003) and gamma-glutamyltransferase (GGT) (st.β = 0.23, P = 0.042) levels at baseline were independently associated with anti-gp210 concentrations. In serial testing, we observed significant fluctuations in anti-gp210 antibody levels. These fluctuations reflected responsiveness to UDCA therapy, particularly in anti-gp210-positive patients with initially lower concentrations in the stages of disease. Conclusions: Our study reflects that quantitative changes of anti-gp210 antibody are indicative of UDCA responses. There is a great need for newer metrics in PBC and we suggest that a more detailed and longer study of these unique ANAs is warranted.

To date, no study has focused on Uvaria macrophylla leaves with various traditional efficiencies. This paper therefore applied a database affinity ultra-high-performance liquid chromatography with quadrupole Orbitrap tandem mass spectrometry (UHPLC-Q-Orbitrap-MS/MS) strategy to analyze the lyophilized aqueous extract of U. macrophylla leaves. Through database comparison and MS fragment elucidation, this study has putatively identified 41 constituents belonging to flavonoid, phenolic acid, steroid, and saccharide natural product classifications. Significantly, four groups of isomers (liquiritigenin vs. isoliquiritigenin vs. pinocembrin; oroxylin A vs. wogonin vs. galangin 3-methyl ether; isoquercitrin vs. hyperoside; protocatechuic acid vs. 2,5-dihydroxybenzoic acid) have been successfully distinguished from each other. All of 41 constituents were then subjected to a quantitative analysis based on linear regression equation established by the above UHPLC-Q-Orbitrap-MS/MS strategy and an ABTS+•-scavenging antioxidant assay. Finally, the chemical content was multiplied by the corresponding ABTS+•-scavenging percentage to calculate the antioxidant contribution. It was shown that the chemical contents of 41 constituents varied from 0.003 ± 0.000 to 14.418 ± 1.041 mg/g, and gallic acid showed the highest antioxidant contribution. Gallic acid is considered as a suitable antioxidant quality-marker (Q-marker) of U. macrophylla leaves. These findings have scientific implications for the resource development and quality control of U. macrophylla leaves.

Quinolizidine alkaloids (QAs) are toxic secondary metabolites of the Lupinus species, the presence of which limits the expansion of lupin beans consumption, despite their high protein content. Evaluation of the level of alkaloids in edible Lupinus species is crucial from a food safety point of view. However, quantitation of QAs is complicated by the fact that not all important alkaloids used for quantitation are commercially available. In this context, we developed a method for the simultaneous quantitation of eight major lupin alkaloids using quantitative NMR spectroscopy (qNMR). Quantitation and analysis were performed in 15 different seed extracts of 11 Lupinus spp. some of which belonged to the same species, with different geographical origins and time of harvest, as well as in all aerial parts of L. pilosus. The mature seeds of L. pilosus were found to be a uniquely rich source of multiflorine. Additionally, we developed a protocol using adsorption or ionic resins for easy, fast, and efficient debittering of the lupine seeds. The protocol was applied to L. albus, leading to a decrease of the time required for alkaloids removal as well as water consumption and to a method for QA isolation from the debittering wastewater. [ABSTRACT FROM AUTHOR]

Mass spectrometry is widely employed in various analytical fields for both compound identification and quantification. While in the case of compound identification, the high‐resolution instrument has increased selectivity and characterization efficiency; in the case of quantitative analysis, some critical tasks actually remain. In particular, different compounds exhibit different ionization efficiency, and this introduces the need to have a calibration standard for each analyte. In this paper, we present a new elaborative data technology, which makes it possible to standardize calibration between different instruments and molecules, making it absolute. The method was applied to data acquired by means of liquid chromatography mass spectrometry by means of an ion trap analyzer. The approach is based on the correlation of the ion trap space charge effect and the analyte concentration. The method was validated in the analysis of compounds having different polarity: hydrossitirosol, arginine, thyodiglicolic acid, and a peptide mixture of bacteria cultures derived the human gut microbiome where was found poliovirus. Moreover, it was used to obtain the absolute quantitation of peptides originating from the tryptic digestion of bacterial proteins in the fecal samples. It was therefore possible to identify and quantify different derived bacterial proteins of the poliomyelitis virus coded in bacteria derived from the gastrointestinal tract. [ABSTRACT FROM AUTHOR]

Selected ion flow tube mass spectrometry, SIFT-MS, has been widely used in industry and research since its introduction in the mid-1990s. Previously described quantitation methods have been advanced to include a gas standard for a more robust and repeatable analytical performance. The details of this approach to calculate the concentrations from ion–molecule reaction kinetics based on reaction times and instrument calibration functions determined from known concentrations in the standard mix are discussed. Important practical issues such as the overlap of product ions are outlined, and best-practice approaches are presented to enable them to be addressed during method development. This review provides a fundamental basis for a plethora of studies in broad application areas that are possible with SIFT-MS instruments. [ABSTRACT FROM AUTHOR]

Pharmaceutical application of therapeutic proteins has been continuously expanded for the treatment of various diseases. Efficient and reliable bioanalytical methods are essential to expedite the identification and successful clinical development of therapeutic proteins. In particular, selective quantitative assays in a high-throughput format are critical for the pharmacokinetic and pharmacodynamic evaluation of protein drugs and to meet the regulatory requirements for new drug approval. However, the inherent complexity of proteins and many interfering substances presented in biological matrices have a great impact on the specificity, sensitivity, accuracy, and robustness of analytical assays, thereby hindering the quantification of proteins. To overcome these issues, various protein assays and sample preparation methods are currently available in a medium- or high-throughput format. While there is no standard or universal approach suitable for all circumstances, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay often becomes a method of choice for the identification and quantitative analysis of therapeutic proteins in complex biological samples, owing to its high sensitivity, specificity, and throughput. Accordingly, its application as an essential analytical tool is continuously expanded in pharmaceutical R&D processes. Proper sample preparation is also important since clean samples can minimize the interference from co-existing substances and improve the specificity and sensitivity of LC-MS/MS assays. A combination of different methods can be utilized to improve bioanalytical performance and ensure more accurate quantification. This review provides an overview of various protein assays and sample preparation methods, with particular emphasis on quantitative protein analysis by LC-MS/MS. [ABSTRACT FROM AUTHOR]

A hydrophilic interaction liquid chromatography tandem mass spectrometry (HILIC/MS/MS) method was developed and validated for the quantitative analysis of the fully phosphorothioate modified oligonucleotide nusinersen. HILIC/MS/MS method is more robust and compatible with mass spectrometry than ion pair reversed-phase liquid chromatography-tandem mass spectrometry (IP-RP-LC/MS/MS). Various types and concentrations of additives and different pH of mobile phase affected the mass spectrometry response, chromatographic peak shape and retention of nusinersen. The optimized extraction method of nusinersen employs hydrophilic-lipophilic balance solid phase extraction, with a recovery of up to 80 %. Chromatographic quantification was performed using a gradient system on an amide column and the mobile phase consisted of ammonium acetate, acetonitrile and water in a certain proportion. The fully phosphorothioate modified nusinersen can obtain a high mass spectrometry response by providing greater peak symmetry and high ionization efficiency in a high-pH mobile phase. Moreover, the significant carry over interference was observed at the pH 6.3 of the mobile phase. Adjusting the pH value up to 10, and the carry over interference disappeared. The lower limit of quantitation of this developed HILIC/MS/MS assay was 30.0 ng/mL and the method was systematic methodology validated. This HILIC/MS/MS method provides an attractive and robust alternative for the quantitative analysis of nusinersen and was applied in the pharmacokinetic study of nusinersen in rabbits.

Abstract Background Q.Clear, a Bayesian penalized likelihood reconstruction algorithm, has shown high potential in improving quantitation accuracy in PET systems. The Q.Clear algorithm controls noise during the iterative reconstruction through a β penalization factor. This study aimed to determine the optimal β-factor for accurate quantitation of dynamic PET scans. Methods A Flangeless Esser PET Phantom with eight hollow spheres (4–25 mm) was scanned on a GE Discovery MI PET/CT system. Data were reconstructed into five sets of variable acquisition times using Q.Clear with 18 different β-factors ranging from 100 to 3500. The recovery coefficient (RC), coefficient of variation (CVRC) and root-mean-square error (RMSERC) were evaluated for the phantom data. Two male patients with recurrent glioblastoma were scanned on the same scanner using 18F-PSMA-1007. Using an irreversible two-tissue compartment model, the area under curve (AUC) and the net influx rate Ki were calculated to assess the impact of different β-factors on the pharmacokinetic analysis of clinical PET brain data. Results In general, RC and CVRC decreased with increasing β-factor in the phantom data. For small spheres (

Objective: An ultra-high liquid chromatography-quadrupole-time of flight mass spectrometry (UPLC-QTOF-MS) was established and applied for the screening and quantitation of pesticide residues in raw milk and infant and young children formula milk powder. Methods: A stable and reliable pretreatment procedure involving quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction and Captiva EMR-lipid cleanup was developed and validated. The samples were separated on a Luna Omega Polar C18 (2.1 mm × 100 mm, 1.6 μm) by gradient elution using mobile phase A consisting of 2 mmol/L ammonium formate and 0.01% formic acid and mobile phase B consisting of 2 mmol/L ammonium formate and 0.01% formic acid. By analyzing commercial pesticide certified reference materials, a single injection method using two fragmentation techniques, collision-induced dissociation (CID) and electron activated dissociation (EAD) was developed for the simultaneous qualitative screening and quantitative analysis of 500 pesticide compounds, in which mass spectrometry data were collected using the Zeno sequential window acquisition of all theoretical fragment ion spectra (SWATH) data-independent acquisition (DIA) mode. Comprehensive scores obtained by the OS software from four factors, including mass deviation, retention time deviation, differential isotope ratio and spectrum library similarity, were used for qualitative screening. The matrix-matched external standard method was used for quantitative analysis based on the peak area of precursor ions in the extracted ion chromatogram (XIC). Results: The comprehensive scores of the 500 pesticides and their metabolites ranged from 90.4 to 99.4 points, higher than the minimum score of qualitative screening (90 points), and the limits of detection (LOD) were in the range of 0.025–0.5 μg/kg. The correlation coefficients (r2) of the matrix-matched calibration curves for 103 pesticides and their metabolites with maximum residue limits (MRL) in milk set by the national standard of China GB 2763-2021 were above 0.99. The average recoveries ranged from 72.7% to 114.5% at three spiked concentration levels with relative standard deviations (RSDs) of 2.1%–13.6% (n = 6), and the limits of quantitation (LOQ) were in the range of 0.15–3 μg/kg. Conclusion: This method was sensitive and accurate, and could be used for the screening identification of multiple pesticides and their metabolites and the quantitative analysis of restricted pesticides with high detection rate in raw milk and infant formula milk powder at low cost.

During chronic hepatitis B virus (HBV) infection, the seroclearance of hepatitis B e antigen (HBeAg) is an important event and a significant surrogate endpoint of all current therapeutic strategies. The prediction of HBeAg seroclearance can help assess the benefits of therapy in patients during or before therapy initiation. The quantitation of HBV core antibodies (qAnti-HBc) is a new non-invasive biomarker for solving multiple diagnostic dilemmas. A systematic review and meta-analysis of studies that measured qAnti-HBc in patients who achieved HBeAg seroclearance were performed through PubMed, Web of Science (WoS) and SCOPUS electronic database searches. Nineteen articles were included in the systematic review, comprising 3434 chronically infected patients (1014 with and 2420 without HBeAg seroclearance). Sixteen publications with data regarding qAnti-HBc levels were included in the meta-analysis. The baseline level of qAnti-HBc antibodies was significantly higher in patients with than without HBeAg seroclearance (SMD = 0.88, 95%CI SMD = 0.56–1.2, p < 0.001). The same conclusion was reached for patients originating from Asia (SMD = 0.94, 95%CI SMD = 0.55–1.33) and for the qAnti-HBc antibodies among adult HBV patients with therapy-induced HBeAg seroclearance (SMD = 0.90, 95%CI SMD = 0.54–1.25, p < 0.001). The systematic review and meta-analysis provide evidence of the role of qAnti-HBc as a promising biomarker for predicting HBeAg seroclearance in chronically infected patients.

In this study, the low-level presence of genetically modified (GM) soybean event GTS-40-3-2 was quantitatively detected and the measurement uncertainty was estimated. Within 95% confidence interval, the quantitative method developed using real-time polymerase chain reaction (PCR) and digital PCR could stably detect 0.01% GTS-40-3-2 content with acceptable cost and uncomplicated operation, while the digital PCR method could quantify 0.1% GTS-40-3-2 content accurately, and the quantitative error did not exceed 50% even at GTS-40-3-2 content as low as 0.05%. The sources of uncertainty in quantitative digital PCR analysis were analyzed, and the calculation formula for uncertainty was derived from calculation models in analytical chemistry. Furthermore, GTS-40-3-2 was used for laboratory verification. The expanded uncertainty in quantitative analysis of 0.1% and 0.05% GTS-40-3-2 contents was calculated as 23.56% and 107.29% (k = 2), respectively.

Abstract Cefoperazone (Cfz) is a member of the third generation of parenteral cephalosporin antibiotics. It is used on a wide scale in prescribed antibiotic drugs as anti-infection, especially for Gram-negative and also against Gram-positive microorganisms. The current study aimed to find a rapid RP-HPLC method of Cfz analysis with high linearity, repeatability, sensitivity, selectivity, and inexpensive. In our developed method, there is no need to use special chemical reagents, a high percentage of organic solvent, a high flow rate, further guard column. The chromatographic system comprises an ODS column (150 mm × 4.6 mm × 5 μm). The mobile phase was prepared by mixing KH2PO4 solution: acetonitrile (80:20) with a flow rate of 1.0 mL/min at detection wavelength 230 nm, at room temperature using injection volume 20 μL. The method manifested a satisfied linearity regression R2 (0.9993) with a good repeatability range (0.34–0.92%) with LOD and LOQ; 4.04 μg/mL and 12.24 μg/mL respectively. The method proved its efficiency via system suitability achievement in the robustness and ruggedness conduction according to the validation guidelines. The shorter analysis time makes the method very valuable in quality control to quantify the commercial Cfz in pharmaceutical preparations. This improved HPLC method has been successfully applied for Cfz analysis for Peracef and Peractam vials in our routine finished and stability studies testing laboratories. Additionally, the detection limit of Cfz has been tested in our quality control lab to detect the smallest amount of traces that may be present after the cleaning process of the production machines for cephalosporins preparations. In a precedent for the first time, we were able to use the current analysis method to determine the minimum inhibitory concentration (MIC) and minimum bacteriostatic concentration (MBC). The conventional broth micro-dilution tube method was used to determine MIC at 250 µg/mL and MBC at 125 µg/mL of Cfz against the standard strain of Burkholderia cepacia (B. cepacia) ATCC 25416 as Gram-negative bacteria in vitro.

Introduction: Reduced mortality in patients with sepsis taking piperacillin is possible when they receive a long-term infusion, which improves the effect of antimicrobials. However, such piperacillin therapy requires therapeutic drug monitoring, the use of the latest analytical equipment and developed methods for the quantitative determination of piperacillin. Materials and Methods: Dry samples of the appropriate certified piperacillin standards were used to prepare stock and standard solutions of piperacillin. Separation of the components was performed using an Agilent 1260 HPLC system with a binary pump and a temperature controlled autosampler. Analyses were detected using a Sciex QTRAP 5500 hybrid mass spectrometric system. Validation of the developed method was carried out in accordance with the rules for conducting bioequivalence studies of drugs within the framework of the Eurasian Economic Union; 2016, in Astana. Results and Discussion: Piperacillin ions-”precursors” corresponded to particles m/z 518.2. The most intense ions-”products” registered during the fragmentation of protonated molecules in the collision cell were particles m/z 143.1 and m/z 115.0. During the validation of the developed method, the main validation parameters were established: linearity, accuracy, accuracy, and sensitivity (lower limit of quantitation). Conclusion: The validated analytical range of the method was 0.5–100 µg/mL in plasma. The resulting analytical range makes it possible to apply the developed method for conducting the analytical part of studies of the pharmacokinetics of piperacillin.

ABSTRACT Metagenomic next-generation sequencing (mNGS) has been a lack of method for pathogen quantitation. We explored the suitable concentration of T1 phage [internal control (IC)phage], Thermus thermophilus (ICT.T), and artificial DNA sequence (ICDNA) as mNGS ICs for pathogen quantitation and compared the quantitation efficiency among them. We prepared the simulated cerebrospinal fluid (CSF) samples composed of a pathogen cocktail, containing Staphylococcus aureus, Escherichia coli, Komagataella pastoris, and human cells to test the accuracy, linearity, and interference of IC quantitation. We also collected 15 clinical CSF conducting both mNGS and droplet digital PCR (ddPCR) to further verify the quantification efficacy of IC. In accuracy, the mNGS quantification of pathogen was more precise when the IC was 103 and 104 CFU/mL Thermus thermophilus or 103 and 104 PFU/mL T1 phage with the CV% of pathogens quantification most below 15%. The DNA sequence’ quantification was less accurate with all the CV% of pathogen quantitation above 15%. In linearity, compared to DNA sequence (all R 2 0.9). In interference, the mNGS quantification was affected obviously by human cell concentrations when the IC was DNA sequence (P < 0.0001), and the quantification was not interfered when the IC was the 103 CFU/mL Thermus thermophilus or 104 PFU/mL T1 phage. Furthermore, we revealed the mNGS quantitation was highly consistent with ddPCR in clinical CSF according to the linear regression (R 2 = 0.9646, P < 0.0001, k = 0.9362) and Bland-Altman (the bias of average difference is 4.033, with the 95% confidence interval from − 24.61 to 32.68). Thermus thermophilus and T1 phages are comparable as mNGS IC in pathogen quantitation and are both superior than artificial DNA sequences. In total, 1,000-CFU/mL Thermus thermophilus as mNGS IC may allow us to reflect directly the variation of pathogens in central nervous system infection patients. IMPORTANCE Metagenomic next-generation sequencing (mNGS) has been used broadly for pathogens detection of infectious diseases. However, there is a lack of method for the absolute quantitation of pathogens by mNGS. We compared the quantitative efficiency of three mNGS internal controls (ICs) Thermus thermophilus, T1 phages, and artificial DNA sequence and developed the most applicable strategies for pathogen quantitation via mNGS in central nervous system infection. The IC application strategy we developed will enable mNGS analysis to assess the pathogen load simultaneously with the detection of pathogens, which should provide critical information for quick decision-making of treatment as well as clinical prognosis.

ABSTRACTHost cell proteins (HCPs) are process-related impurities derived from the manufacturing of recombinant biotherapeutics. Residual HCP in drug products, ranging from 1 to 100 ppm (ng HCP/mg product) or even below sub-ppm level, may affect product quality, stability, efficacy, or safety. Therefore, removal of HCPs to appropriate levels is critical for the bioprocess development of biotherapeutics. Liquid chromatography-mass spectrometry (LC-MS) analysis has become an important tool to identify, quantify, and monitor the clearance of individual HCPs. This review covers the technical advancement of sample preparation strategies, new LC-MS-based techniques, and data analysis approaches to robustly and sensitively measure HCPs while overcoming the high dynamic range analytical challenges. We also discuss our strategy for LC-MS-based HCP workflows to enable fast support of process development throughout the product life cycle, and provide insights into developing specific analytical strategies leveraging LC-MS tools to control HCPs in process and mitigate their potential risks to drug quality, stability, and patient safety.

AbstractPharmaceutical application of therapeutic proteins has been continuously expanded for the treatment of various diseases. Efficient and reliable bioanalytical methods are essential to expedite the identification and successful clinical development of therapeutic proteins. In particular, selective quantitative assays in a high-throughput format are critical for the pharmacokinetic and pharmacodynamic evaluation of protein drugs and to meet the regulatory requirements for new drug approval. However, the inherent complexity of proteins and many interfering substances presented in biological matrices have a great impact on the specificity, sensitivity, accuracy, and robustness of analytical assays, thereby hindering the quantification of proteins. To overcome these issues, various protein assays and sample preparation methods are currently available in a medium- or high-throughput format. While there is no standard or universal approach suitable for all circumstances, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay often becomes a method of choice for the identification and quantitative analysis of therapeutic proteins in complex biological samples, owing to its high sensitivity, specificity, and throughput. Accordingly, its application as an essential analytical tool is continuously expanded in pharmaceutical R&D processes. Proper sample preparation is also important since clean samples can minimize the interference from co-existing substances and improve the specificity and sensitivity of LC-MS/MS assays. A combination of different methods can be utilized to improve bioanalytical performance and ensure more accurate quantification. This review provides an overview of various protein assays and sample preparation methods, with particular emphasis on quantitative protein analysis by LC-MS/MS.

Background: Q.Clear, a Bayesian penalized likelihood reconstruction algorithm, has shown high potential in improving quantitation accuracy in PET systems. The Q.Clear algorithm controls noise during the iterative reconstruction through a β penalization factor. This study aimed to determine the optimal β-factor for accurate quantitation of dynamic PET scans. Methods: A Flangeless Esser PET Phantom with eight hollow spheres (4–25 mm) was scanned on a GE Discovery MI PET/CT system. Data were reconstructed into five sets of variable acquisition times using Q.Clear with 18 different β-factors ranging from 100 to 3500. The recovery coefficient (RC), coefficient of variation (CVRC) and root-mean-square error (RMSERC) were evaluated for the phantom data. Two male patients with recurrent glioblastoma were scanned on the same scanner using 18F-PSMA-1007. Using an irreversible two-tissue compartment model, the area under curve (AUC) and the net influx rate Ki were calculated to assess the impact of different β-factors on the pharmacokinetic analysis of clinical PET brain data. Results: In general, RC and CVRC decreased with increasing β-factor in the phantom data. For small spheres (< 10 mm), and in particular for short acquisition times, low β-factors resulted in high variability and an overestimation of measured activity. Increasing the β-factor improves the variability, however at a cost of underestimating the measured activity. For the clinical data, AUC decreased and Ki increased with increased β-factor; a change in β-factor from 300 to 1000 resulted in a 25.5% increase in the Ki. Conclusion: In a complex dynamic dataset with variable acquisition times, the optimal β-factor provides a balance between accuracy and precision. Based on our results, we suggest a β-factor of 300–500 for quantitation of small structures with dynamic PET imaging, while large structures may benefit from higher β-factors. Trial registration: Clinicaltrials.gov, NCT03951142. Registered 5 October 2019, https://clinicaltrials.gov/ct2/show/NCT03951142. EudraCT no 2018-003229-27. Registered 26 February 2019, https://www.clinicaltrialsregister.eu/ctr-search/trial/2018-003229-27/NO. [ABSTRACT FROM AUTHOR]

The vast quantity and high variety of pesticides globally used in agriculture entails considerable risks for the environment and requires ensuring the safety of food products. Therefore, powerful analytical tools are needed to acquire qualitative and quantitative data for monitoring pesticide residues. The development of ambient ionization mass spectrometry methods in the past two decades has demonstrated numerous ways to generate ions under atmospheric conditions and simultaneously to reduce the need for extended sample preparation and circumvent chromatographic separation prior to mass analysis. Swab spray ionization enables the generation of ions directly from swabs via the application of high voltage and solvent flow. In this study, swab sampling of fruit surfaces and subsequent ionization directly from the swab in a modified electrospray ion source was employed for the screening and quantitation of pesticide residues. Aspects regarding sample collection, sampling efficacy on different surfaces, and swab background are discussed. The effect of solvent composition on pesticide-sodium adduct formation and the suppression of ionization by the background matrix have been investigated. Furthermore, a novel approach for the quantitation of pesticide residues based on depletion curve areas is presented. It is demonstrated that swab spray ionization is an effective and quick method for spectral library-based identification and the quantitative analysis of polar contact pesticide residues on food. [ABSTRACT FROM AUTHOR]

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Objective: Tau positron emission tomography (PET) imaging is a recently developed non-invasive tool that can detect the density and extension of tau neurofibrillary tangles. Tau PET tracers have been validated to harmonize and accelerate their development and implementation in clinical practice. Whereas standard protocols including injected dose, uptake time, and duration have been determined for tau PET tracers, reconstruction parameters have not been standardized. The present study conducted phantom experiments based on tau pathology to standardize quantitative tau PET imaging parameters and optimize reconstruction conditions of PET scanners at four Japanese sites according to the results of phantom experiments. Methods: The activity of 4.0 and 2.0 kBq/mL for Hoffman 3D brain and cylindrical phantoms, respectively, was estimated from published studies of brain activity using [18F]flortaucipir, [18F]THK5351, and [18F]MK6240. We developed an original tau-specific volume of interest template for the brain based on pathophysiological tau distribution in the brain defined as Braak stages. We acquired brain and cylindrical phantom images using four PET scanners. Iteration numbers were determined as contrast and recover coefficients (RCs) in gray (GM) and white (WM) matter, and the magnitude of the Gaussian filter was determined from image noise. Results: Contrast and RC converged at ≥ 4 iterations, the error rates of RC for GM and WM were < 15% and 1%, respectively, and noise was < 10% in Gaussian filters of 2–4 mm in images acquired using the four scanners. Optimizing the reconstruction conditions for phantom tau PET images acquired by each scanner improved contrast and image noise. Conclusions: The phantom activity was comprehensive for first- and second-generation tau PET tracers. The mid-range activity that we determined could be applied to later tau PET tracers. We propose an analytical tau-specific VOI template based on tau pathophysiological changes in patients with AD to standardize tau PET imaging. Phantom images reconstructed under the optimized conditions for tau PET imaging achieved excellent image quality and quantitative accuracy. [ABSTRACT FROM AUTHOR]