Innovative assessment of lipid-induced oxidative stress and inflammation in harvested human endothelial cells.

Studying acute changes in vascular endothelial cells in humans is challenging. We studied ten African American women and used the J-wire technique to isolate vein endothelial cells before and after a four-hour lipid and heparin infusion. Dynamic changes in lipid-induced oxidative stress and inflammatory markers were measured with fluorescence-activated cell sorting. We used the surface markers CD31 and CD144 to identify human endothelial cells. Peripheral blood mononuclear cells isolated from blood were used as a negative control. The participants received galantamine (16 mg/day) for 3 months. We previously demonstrated that galantamine treatment effectively suppresses lipid-induced oxidative stress and inflammation. In this study, we infused lipids to evaluate its potential to increase the activation of endothelial cells, as assessed by the levels of CD54+ endothelial cells and expression of Growth arrest-specific 6 compared to the baseline sample. Further, we aimed to investigate whether lipid infusion led to increased expression of the oxidative stress markers IsoLGs and nitrotyrosine in endothelial cells. This approach will expedite the in vivo identification of novel pathways linked with endothelial cell dysfunction induced by oxidative stress and inflammatory cytokines. This study describes an innovative method to harvest and study human endothelial cells and demonstrates the dynamic changes in oxidative stress and inflammatory markers release induced by lipid infusion.

MRI and 18F-FET PET for Multimodal Treatment Monitoring in Patients with Brain Metastases: A Cost-Effectiveness Analysis.

PET using the radiolabeled amino acid O-(2-[18F]fluoroethyl)-l-tyrosine (18F-FET) has been shown to be of value for treatment monitoring in patients with brain metastases after multimodal therapy, especially in clinical situations with equivocal MRI findings. As medical procedures must be justified socioeconomically, we determined the effectiveness and cost-effectiveness of 18F-FET PET for treatment monitoring of multimodal therapy, including checkpoint inhibitors, targeted therapies, radiotherapy, and combinations thereof in patients with brain metastases secondary to melanoma or non-small cell lung cancer. Methods: We analyzed already-published clinical data and calculated the associated costs from the German statutory health insurance system perspective. Two clinical scenarios were considered: decision tree model 1 determined the effectiveness of 18F-FET PET alone for identifying treatment-related changes, that is, the probability of correctly identifying patients with treatment-related changes confirmed by neuropathology or clinicoradiographically using the Response Assessment in Neuro-Oncology criteria for immunotherapy. The resulting cost-effectiveness ratio showed the cost for each correctly identified patient with treatment-related changes in whom MRI findings remained inconclusive. Decision tree model 2 calculated the effectiveness of both 18F-FET PET and MRI, that is, the probability of correctly identifying nonresponders to treatment. The incremental cost-effectiveness ratio was calculated to determine cost-effectiveness, that is, the cost for each additionally identified nonresponder by 18F-FET PET who would have remained undetected by MRI. One-way deterministic and probabilistic sensitivity analyses tested the robustness of the results. Results: 18F-FET PET identified 94% of patients with treatment-related changes, resulting in €1,664.23 (€1.00 = $1.08 at time of writing) for each correctly identified patient. Nonresponders were correctly identified in 60% by MRI and in 80% by 18F-FET PET, resulting in €3,292.67 and €3,915.83 for each correctly identified nonresponder by MRI and 18F-FET PET, respectively. The cost to correctly identify 1 additional nonresponder by 18F-FET PET, who would have remained unidentified by MRI, was €5,785.30. Conclusion: Given the considerable annual cost of multimodal therapy, the integration of 18F-FET PET can potentially improve patient care while reducing costs.

Assessment of Brain Tumour Perfusion Using Early-Phase 18F-FET PET: Comparison with Perfusion-Weighted MRI.

PURPOSE: Morphological imaging using MRI is essential for brain tumour diagnostics. Dynamic susceptibility contrast (DSC) perfusion-weighted MRI (PWI), as well as amino acid PET, may provide additional information in ambiguous cases. Since PWI is often unavailable in patients referred for amino acid PET, we explored whether maps of relative cerebral blood volume (rCBV) in brain tumours can be extracted from the early phase of PET using O-(2-18F-fluoroethyl)-L-tyrosine (18F-FET). PROCEDURE: Using a hybrid brain PET/MRI scanner, PWI and dynamic 18F-FET PET were performed in 33 patients with cerebral glioma and four patients with highly vascularized meningioma. The time interval from 0 to 2 min p.i. was selected to best reflect the blood pool phase in 18F-FET PET. For each patient, maps of MR-rCBV, early 18F-FET PET (0-2 min p.i.) and late 18F-FET PET (20-40 min p.i.) were generated and coregistered. Volumes of interest were placed on the tumour (VOI-TU) and normal-appearing brain (VOI-REF). The correlation between tumour-to-brain ratios (TBR) of the different parameters was analysed. In addition, three independent observers evaluated MR-rCBV and early 18F-FET maps (18F-FET-rCBV) for concordance in signal intensity, tumour extent and intratumoural distribution. RESULTS: TBRs calculated from MR-rCBV and 18F-FET-rCBV showed a significant correlation (r = 0.89, p < 0.001), while there was no correlation between late 18F-FET PET and MR-rCBV (r = 0.24, p = 0.16) and 18F-FET-rCBV (r = 0.27, p = 0.11). Visual rating yielded widely agreeing findings or only minor differences between MR-rCBV maps and 18F-FET-rCBV maps in 93 % of the tumours (range of three independent raters 91-94%, kappa among raters 0.78-1.0). CONCLUSION: Early 18F-FET maps (0-2 min p.i.) in gliomas provide similar information to MR-rCBV maps and may be helpful when PWI is not possible or available. Further studies in gliomas are needed to evaluate whether 18F-FET-rCBV provides the same clinical information as MR-rCBV.

Leptin and energy balance: exploring Leptin's role in the regulation of energy intake and energy expenditure.

Leptin is a tonic appetite-regulating hormone, which is integral for the long-term regulation of energy balance. The current evidence suggests that the typical orexigenic or anorexigenic response of many of these appetite-regulating hormones, most notably ghrelin and cholecystokinin (CCK), require leptin to function whereas glucagon-like peptide-1 (GLP-1) is required for leptin to function, and these responses are altered when leptin injection or gene therapy is administered in combination with these same hormones or respective agonists. The appetite-regulatory pathway is complex, thus peptide tyrosine tyrosine (PYY), brain-derived neurotrophic factor (BDNF), orexin-A (OXA), and amylin also maintain ties to leptin, however these are less well understood. While reviews to date have focused on the existing relationships between leptin and the various neuropeptide modulators of appetite within the central nervous system (CNS) or it's role in thermogenesis, no review paper has synthesised the information regarding the interactions between appetite-regulating hormones and how leptin as a chronic regulator of energy balance can influence the acute appetite-regulatory response. Current evidence suggests that potential relationships exist between leptin and the circulating peripheral appetite hormones ghrelin, GLP-1, CCK, OXA and amylin to exhibit either synergistic or opposing effects on appetite inhibition. Though more research is warranted, leptin appears to be integral in both energy intake and energy expenditure. More specifically, functional leptin receptors appear to play an essential role in these processes.

Automated Brain Tumor Detection and Segmentation for Treatment Response Assessment Using Amino Acid PET.

Evaluation of metabolic tumor volume (MTV) changes using amino acid PET has become an important tool for response assessment in brain tumor patients. MTV is usually determined by manual or semiautomatic delineation, which is laborious and may be prone to intra- and interobserver variability. The goal of our study was to develop a method for automated MTV segmentation and to evaluate its performance for response assessment in patients with gliomas. Methods: In total, 699 amino acid PET scans using the tracer O-(2-[18F]fluoroethyl)-l-tyrosine (18F-FET) from 555 brain tumor patients at initial diagnosis or during follow-up were retrospectively evaluated (mainly glioma patients, 76%). 18F-FET PET MTVs were segmented semiautomatically by experienced readers. An artificial neural network (no new U-Net) was configured on 476 scans from 399 patients, and the network performance was evaluated on a test dataset including 223 scans from 156 patients. Surface and volumetric Dice similarity coefficients (DSCs) were used to evaluate segmentation quality. Finally, the network was applied to a recently published 18F-FET PET study on response assessment in glioblastoma patients treated with adjuvant temozolomide chemotherapy for a fully automated response assessment in comparison to an experienced physician. Results: In the test dataset, 92% of lesions with increased uptake (n = 189) and 85% of lesions with iso- or hypometabolic uptake (n = 33) were correctly identified (F1 score, 92%). Single lesions with a contiguous uptake had the highest DSC, followed by lesions with heterogeneous, noncontiguous uptake and multifocal lesions (surface DSC: 0.96, 0.93, and 0.81 respectively; volume DSC: 0.83, 0.77, and 0.67, respectively). Change in MTV, as detected by the automated segmentation, was a significant determinant of disease-free and overall survival, in agreement with the physician's assessment. Conclusion: Our deep learning-based 18F-FET PET segmentation allows reliable, robust, and fully automated evaluation of MTV in brain tumor patients and demonstrates clinical value for automated response assessment.

Development of an economical method to synthesize O-(2-[18 F]fluoroethyl)-L-tyrosine (18 FFET).

Positron emission tomography (PET) using O-(2-[18 F]fluoroethyl)-L-tyrosine ([18 F]FET) has shown great success in differentiating tumor recurrence from necrosis. In this study, we are reporting the experience of synthesis [18 F]FET by varying the concentration of TET precursor in different chemistry modules. TET precursor (2-10 mg) was used for the synthesis of [18 F]FET in an automated (MX Tracerlab) module (n = 6) and semiautomated (FX2N Tracerlab) module (n = 19). The quality control was performed for all the preparations. For human imaging, 220 ± 50 MBq of [18 F]FET was briefly injected into the patient to acquire PET-MR images. The radiochemical purity was greater than 95% for the final product in both modules. The decay corrected average yield was 10.7 ± 4.7% (10 mg, n = 3) and 8.2 ± 2.6% (2 mg, n = 3) with automated chemistry module and 36.7 ± 7.3% (8-10 mg, n = 12), 26.4 ± 3.1% (5-7 mg, n = 4), and 35.1 ± 3.8% (2-4 mg, n = 3) with semiautomated chemistry modules. The PET imaging showed uptake at the lesion site (SUVmax = 7.5 ± 2.6) and concordance with the MR image. The [18 F]FET was produced with a higher radiochemical yield with 2.0 mg of the precursor with substantial yield and is suitable for brain tumor imaging.

Beyond Rule-of-five: Permeability Assessment of Semipeptidic Macrocycles.

Compounds beyond the rule-of-five are generating interest as they expand the molecular toolbox for modulating targets previously considered "undruggable". Macrocyclic peptides are an efficient class of molecules for modulating protein-protein interactions. However, predicting their permeability is difficult as they differ from small molecules. Although constrained by macrocyclization, they generally retain some conformational flexibility associated with an enhanced ability to cross biological membranes. In this study, we investigated the relationship between the structure of semi-peptidic macrocycles and their membrane permeability through structural modifications. Based on a scaffold of four amino acids and a linker, we synthesized 56 macrocycles incorporating modifications in either stereochemistry, N-methylation, or lipophilicity and assessed their passive permeability using the parallel artificial membrane permeability assay (PAMPA). Our results show that some semi-peptidic macrocycles have adequate passive permeability even with properties outside the Lipinski rule of five. We found that N-methylation in position 2 and the addition of lipophilic groups to the side chain of tyrosine led to an improvement in permeability with a decrease in tPSA and 3D-PSA. This enhancement could be attributed to the shielding effect of the lipophilic group on some regions of the macrocycle, which in turn, facilitates a favorable macrocycle conformation for permeability, suggesting some degree of chameleonic behavior.

Selective Inhibitor Design for Kinase Homologs Using Multiobjective Monte Carlo Tree Search.

Designing highly selective molecules for a drug target protein is a challenging task in drug discovery. This task can be regarded as a multiobjective problem that simultaneously satisfies criteria for various objectives, such as selectivity for a target protein, pharmacokinetic endpoints, and drug-like indices. Recent breakthroughs in artificial intelligence have accelerated the development of molecular structure generation methods, and various researchers have applied them to computational drug designs and successfully proposed promising drug candidates. However, designing efficient selective inhibitors with releasing activities against various homologs of a target protein remains a difficult issue. In this study, we developed a de novo structure generator based on reinforcement learning that is capable of simultaneously optimizing multiobjective problems. Our structure generator successfully proposed selective inhibitors for tyrosine kinases while optimizing 18 objectives consisting of inhibitory activities against 9 tyrosine kinases, 3 pharmacokinetics endpoints, and 6 other important properties. These results show that our structure generator and optimization strategy for selective inhibitors will contribute to the further development of practical structure generators for drug designs.

Late isocaloric eating increases hunger, decreases energy expenditure, and modifies metabolic pathways in adults with overweight and obesity.

Late eating has been linked to obesity risk. It is unclear whether this is caused by changes in hunger and appetite, energy expenditure, or both, and whether molecular pathways in adipose tissues are involved. Therefore, we conducted a randomized, controlled, crossover trial (ClinicalTrials.gov NCT02298790) to determine the effects of late versus early eating while rigorously controlling for nutrient intake, physical activity, sleep, and light exposure. Late eating increased hunger (p < 0.0001) and altered appetite-regulating hormones, increasing waketime and 24-h ghrelin:leptin ratio (p < 0.0001 and p = 0.006, respectively). Furthermore, late eating decreased waketime energy expenditure (p = 0.002) and 24-h core body temperature (p = 0.019). Adipose tissue gene expression analyses showed that late eating altered pathways involved in lipid metabolism, e.g., p38 MAPK signaling, TGF-ß signaling, modulation of receptor tyrosine kinases, and autophagy, in a direction consistent with decreased lipolysis/increased adipogenesis. These findings show converging mechanisms by which late eating may result in positive energy balance and increased obesity risk.

Fluorescence Quenching of Tyrosine-Ag Nanoclusters by Metal Ions: Analytical and Physicochemical Assessment.

A new synthesis method is described for the first time to produce silver nanoclusters (AgNCs) by using the tyrosine (Tyr) amino acid. Several important parameters (e.g., molar ratios, initial pH, reaction time etc.) were optimized to reach the highest yield. The formed Tyr-AgNCs show characteristic blue emission at λem = 410 nm, and two dominant fluorescence lifetime components were deconvoluted (τ1 ~ 3.7 and τ2 ~ 4.9 ns). The NCs contained metallic cores stabilized by dityrosine. For possible application, the interactions with several metal ions from the tap water and wastewater were investigated. Among the studied cations, four different ions (Cu2+, Ni2+, Fe3+, and Rh3+) had a dominant effect on the fluorescence of NCs. Based on the detected quenching processes, the limit of detection of the metal ions was determined. Static quenching (formation of a non-luminescent complex) was observed in all cases by temperature-dependent measurements. The calculated thermodynamic parameters showed that the interactions are spontaneous ranked in the following order of strength: Cu2+ > Fe3+ > Rh3+ > Ni2+. Based on the sign and relations of the standard enthalpy (ΔH°) and entropy changes (ΔS°), the dominant forces were also identified.

Chromosomal-level genome of velvet bean (Mucuna pruriens) provides resources for L-DOPA synthetic research and development.

Mucuna pruriens, commonly called velvet bean, is the main natural source of levodopa (L-DOPA), which has been marketed as a psychoactive drug for the clinical management of Parkinson's disease and dopamine-responsive dystonia. Although velvet bean is a very important plant species for food and pharmaceutical manufacturing, the lack of genetic and genomic information about this species severely hinders further molecular research thereon and biotechnological development. Here, we reported the first velvet bean genome, with a size of 500.49 Mb and 11 chromosomes encoding 28,010 proteins. Genomic comparison among legume species indicated that velvet bean speciated ∼29 Ma from soybean clade, without specific genome duplication. Importantly, we identified 21 polyphenol oxidase coding genes that catalyse l-tyrosine to L-DOPA in velvet bean, and two subfamilies showing tandem expansion on Chr3 and Chr7 after speciation. Interestingly, disease-resistant and anti-pathogen gene families were found contracted in velvet bean, which might be related to the expansion of polyphenol oxidase. Our study generated a high-quality genomic reference for velvet bean, an economically important agricultural and medicinal plant, and the newly reported L-DOPA biosynthetic genes could provide indispensable information for the biotechnological and sustainable development of an environment-friendly L-DOPA biosynthesis processing method.

Cost Effectiveness of 18F-FET PET for Early Treatment Response Assessment in Glioma Patients After Adjuvant Temozolomide Chemotherapy.

In light of increasing health-care costs, higher medical expenses should be justified socioeconomically. Therefore, we calculated the effectiveness and cost effectiveness of PET using the radiolabeled amino acid O-(2-18F-fluoroethyl)-l-tyrosine (18F-FET) compared with conventional MRI for early identification of responders to adjuvant temozolomide chemotherapy. A recently published study in isocitrate dehydrogenase wild-type glioma patients suggested that 18F-FET PET parameter changes predicted a significantly longer survival already after 2 cycles whereas MRI changes were not significant. Methods: To determine the effectiveness and cost effectiveness of serial 18F-FET PET imaging, we analyzed published clinical data and calculated the associated costs from the perspective of the German Statutory Health Insurance system. Based on a decision-tree model, the effectiveness of 18F-FET PET and MRI was calculated-that is, the probability to correctly identify a responder as defined by an overall survival of at least 15 mo. To determine the cost effectiveness, the incremental cost effectiveness ratio (ICER) was calculated-that is, the cost for each additionally identified responder by 18F-FET PET who would have remained undetected by MRI. The robustness of the results was tested by deterministic and probabilistic Monte Carlo sensitivity analyses. Results: Compared with MRI, 18F-FET PET increased the rate of correctly identified responders to chemotherapy by 26%; thus, 4 patients needed to be examined by 18F-FET PET to identify 1 additional responder. Considering the respective costs for serial 18F-FET PET and MRI, the ICER resulted in €4,396.83 for each additional correctly identified responder by 18F-FET PET. Sensitivity analyses confirmed the robustness of the results. Conclusion: In contrast to conventional MRI, the model suggests that 18F-FET PET is cost-effective in terms of ICER values. Considering the high cost of temozolomide, the integration of 18F-FET PET has the potential to avoid premature chemotherapy discontinuation at reasonable cost.

Non-viral siRNA transfection of primary mesenchymal stromal cells (MSCs): Assessment of tyrosine-modified PEI and PPI efficacy and biocompatibility.

Mesenchymal stromal cells (MSCs) are multipotent cells derived from different sources and able to differentiate into distinct cell lineages. For their possible biomedical application, the "tuning" of MSCs also involves the specific knockdown of defined target genes. A major limitation, however, is the notoriously low transfection efficacy especially of primary MSCs. In this paper, we systemically analyze a large set of tyrosine-modified linear or branched low molecular weight polyethylenimines (PEIs) of different sizes, as well as the tyrosine-modified polypropylenimine dendrimer PPI-G4, for their capacity of non-viral siRNA transfection into umbilical cord-derived MSCs from two different donors. Knockdown efficacies are determined on the molecular level and confirmed in functional assays. Beyond the determination of cell viabilities, acute cytotoxicity, induction of apoptosis/necrosis and mitochondrial membrane alterations are also studied. On the molecular level, caspase activation, ROS induction and genotoxic effects are analyzed. Major differences are observed between the various tyrosine-modified PEIs, with some candidates showing high knockdown efficacy and biocompatibility. PPI-G4-Y dendrimers, however, are identified as most efficient for siRNA transfection into MSCs. PPI-G4-Y/siRNA nanoparticles lead to particularly high gene knockdown, without cytotoxic and genotoxic effects on the cellular and molecular level, and are thus particularly well-suited for the tuning of MSCs.

Assessment of Seasonal Variability of the Spectrum of Free Amino Acids in the Blood Plasma of the Boreal Bat Species (Myotis dasycneme Boie, 1825) of the Ural Fauna.

A comparative analysis of the content of free amino acids in the blood plasma of a representative of the bat fauna of the Urals, Myotis dasycneme (Boie, 1825), in seasonal periods of their annual life cycle is presented for the first time. The blood plasma of the pond bats contains a full spectrum of essential amino acids: threonine, valine, lysine, leucine, isoleucine, methionine, phenylalanine, arginine, histidine, and tryptophan. A significant accumulation of metabolically active glucoplastic alanine in the blood of M. dasycneme in the autumn (2.5 times) and winter (2.2 times) periods indicates its role as a low-temperature adaptogen.

Functional in vitro assessment of modified antibodies: Impact of label on protein properties.

Labelling of therapeutic antibodies with radionuclides or fluorophores is routinely used to study their pharmacokinetic properties. A critical assumption in utilizing labelled therapeutic antibodies is that the label has no unfavourable effects on antibody charge, hydrophobicity, or receptor affinity. Ideally, the labelled protein should not have any significant deviations from the physiological properties of the original molecule. This article describes an established quality in vitro assessment workflow for labelled antibodies that ensures better prediction of changes in antibody pharmacokinetic (PK) properties after modifications. This analysis package considers degradation and aggregation analysis by size-exclusion chromatography, changes in neonatal-Fc-receptor (FcRn) affinity, and heparin interaction. FcRn binding is important for antibody recycling and half-life extension, whereas heparin affinity provides estimates on the rate of endocytosis through unspecific cell surface binding. Additionally, mass spectrometric analysis to determine the degree of labelling (DoL) completes the package and the combined analysis data allow to predict the label contribution to the PK properties of the modified antibody. This analytical strategy for labelling 11 IgGs has been investigated using 2 different IgG1 constructs and applying 7 different types of labels. Each labelling resulted in a change in the physicochemical properties of the protein. Not only can the DoL of modified IgGs lead to a change in protein properties, but the type of label also can. Furthermore, it was demonstrated that the labelling process can also influence the behaviour of labelled mAbs. An identical label on different constructs of IgG1 can cause different affinities for FcRn and heparin. Considering the assessment data, only 6 of the 11 modified antibodies from this study can be recommended for subsequent experiments. In conclusion, a suitability assessment of labelled antibodies prior to any pharmacokinetic studies is essential to reduce cost, allocate resources and reduce the number of animal experiments during pre-clinical drug development.

"Covalent biosensing" enables a one-step, reagent-less, low-cost and highly robust assay of SARS-CoV-2.

We have established a new protocol for detecting severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) using a peptidomimetic to covalently detect a viral marker protease.

Repeatability of image features extracted from FET PET in application to post-surgical glioblastoma assessment.

Positron emission tomography (PET) imaging using the amino acid tracer O-[2-(18F)fluoroethyl]-L-tyrosine (FET) has gained increased popularity within the past decade in the management of glioblastoma (GBM). Radiomics features extracted from FET PET images may be sensitive to variations when imaging at multiple time points. It is therefore necessary to assess feature robustness to test-retest imaging. Eight patients with histologically confirmed GBM that had undergone post-surgical test-retest FET PET imaging were recruited. In total, 1578 radiomic features were extracted from biological tumour volumes (BTVs) delineated using a semi-automatic contouring method. Feature repeatability was assessed using the intraclass correlation coefficient (ICC). The effect of both bin width and filter choice on feature repeatability was also investigated. 59/106 (55.7%) features from the original image and 843/1472 (57.3%) features from filtered images had an ICC ≥ 0.85. Shape and first order features were most stable. Choice of bin width showed minimal impact on features defined as stable. The Laplacian of Gaussian (LoG, σ = 5 mm) and Wavelet filters (HLL and LHL) significantly improved feature repeatability (p ≪ 0.0001, p = 0.003, p = 0.002, respectively). Correlation of textural features with tumour volume was reported for transparency. FET PET radiomic features extracted from post-surgical images of GBM patients that are robust to test-retest imaging were identified. An investigation with a larger dataset is warranted to validate the findings in this study.

Multimodal assessment of disease activity in glioblastoma : A single center experience.

BACKGROUND: Assessment of disease activity in glioblastoma (GBM) can be challenging due to several clinical and radiological pitfalls. Besides MRI, FET-PET and neurocognitive assessment (NA) are used in several neuro-oncological centers in order to improve the specificity of response assessment. We performed a retrospective study to investigate whether the assessment by RANO (Response Assessment in NeuroOncology) corresponds to FET-PET imaging and NA results. Moreover, the concordance of RANO with a final recommendation of an interdisciplinary neuro-oncological tumor board recommendation (TBR) was analyzed. METHODS: We enrolled 25 consecutive patients with newly diagnosed histologically confirmed GBM in a pilot study, accounting for 81 multimodal test results. All patients were selected after undergoing consecutive follow-up comprising MRI, FET-PET, and NA with a subsequent TBR. Results were analyzed for correlations between RANO, FET-PET and NA. An additional consistency analysis was performed to elucidate the impact of RANO on decision making. RESULTS: A highly statistically significant correlation was found between RANO and FET-PET and NA results (all P < 0.01); however, 26% of follow-up tests exhibited inconsistent results in multimodal assessment, among which RANO was only 48% in accordance with the final TBR. The concordance of NA and FET-PET with the final TBR was 67% and 86%, respectively. CONCLUSION: The RANO proved its value in the context of multimodal assessment of disease activity in GBM; however, because the implementation of multimodal assessment showed a considerably high percentage of inconsistent results, further studies are required to investigate the relationship between different assessment techniques, in addition to their overall significance to response rating.

Assessment of serum phenylalanine and tyrosine isomers in patients with ST-segment elevation vs non-ST-segment elevation myocardial infarction.

BACKGROUND: Under conditions of oxidative stress, hydroxyl radicals can oxidize phenylalanine (Phe) into various tyrosine (Tyr) isomers (meta-, ortho-, and para-tyrosine; m-, o-, and p-Tyr), depending on the location of the hydroxyl group on the oxidized benzyl ring. This study aimed to compare patients with ST-segment elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI) and the serum levels of Phe and Tyr isomers at the aortic root and distal to the culprit lesion in both groups. METHODS: Forty-four patients participated in the study: 23 with STEMI and 21 with NSTEMI. Arterial blood samples were taken from the aortic root through a guiding catheter and from the culprit vessel segment distal from the primary lesion with an aspiration catheter, during the percutaneous coronary intervention. Serum levels of Phe, p-Tyr, m-Tyr, and o-Tyr were determined using reverse-phase high-performance liquid chromatography. RESULTS: Serum levels of Phe were significantly higher distal to the culprit lesion compared to the aortic root in patients with STEMI. Serum p-Tyr/Phe and m-Tyr/Phe concentration ratios were both lower distal to the culprit lesion than at the aortic root in patients with STEMI. There were no statistically significant differences with respect to changes in serum Phe and Tyr isomers distal to the culprit lesion compared to the aortic root in patients with NSTEMI. CONCLUSION: Our data suggest that changes in serum levels of different Tyr isomers can mediate the effects of oxidative stress during myocardial infarction.

Assessment of Thyroid Function in Patients With Alkaptonuria.

Importance: Alkaptonuria is an autosomal recessive disorder caused by pathogenic variants in the HGD gene. Deficiency of the HGD enzyme leads to tissue deposition of homogentisic acid (HGA), causing severe osteoarthropathies and cardiac valve degeneration. Although HGD is vital for the catabolism of tyrosine, which provides the basis for thyroid hormone synthesis, the prevalence of thyroid dysfunction in alkaptonuria is unknown. Objective: To assess thyroid structure and function in patients with alkaptonuria. Design, Setting, and Participants: A single-center cohort study was conducted in a tertiary referral center including patients with alkaptonuria followed up for a median of 93 (interquartile range, 48-150) months between February 1, 2000, and December 31, 2018. The alkaptonuria diagnosis was based on clinical presentation and elevated urine HGA levels. A total of 130 patients were considered for participation. Main Outcomes and Measures: Prevalence of thyroid dysfunction in adults with alkaptonuria compared with the general population. Thyrotropin and free thyroxine levels were measured by immunoassay and repeated in each patient a median of 3 (interquartile range, 2-22) times. Neck ultrasonographic scans were analyzed in a subset of participants. Logistic regression was used to test the association of thyroid dysfunction with age, sex, thyroid peroxidase (TPO) antibodies, serum tyrosine levels, and urine HGA levels. Results: Of the 130 patients, 5 were excluded owing to thyroidectomy as the cause of hypothyroidism. The study cohort consisted of 125 patients; the median age was 45 (interquartile range, 35-51) years. Most of the patients were men (72 [57.6%]). The prevalence of primary hyperthyroidism was 0.8% (1 of 125 patients), similar to 0.5% observed in the general population (difference, 0.003; 95% CI, -0.001 to 0.04; P = .88). The prevalence of primary hypothyroidism was 16.0% (20 of 125 patients), which is significantly higher than 3.7% reported in the general population (difference, 0.12; 95% CI, 0.10-0.24; P < .001). Women were more likely to have primary hypothyroidism than men (odds ratio, 10.99; 95% CI, 3.13-38.66; P < .001). Patients with TPO antibodies had a higher likelihood of primary hypothyroidism than those without TPO antibodies (odds ratio, 7.36; 95% CI, 1.89-28.62; P = .004). There was no significant difference in the prevalence of thyroid nodules between patients in this study (29 of 49 [59.2%]) vs the general population (68%) (difference, 0.088; 95% CI, -0.44 to 0.73; P = .20) or of cancer (7% vs 5%; difference, 0.01; 95% CI, -0.01 to 0.17; P = .86). Conclusions and Relevance: The high prevalence of primary hypothyroidism noted in patients with alkaptonuria in this study suggests that serial screening in this population should be considered and prioritized.