Ginseng total saponin improves red blood cell oxidative stress injury by regulating tyrosine phosphorylation and glycolysis in red blood cells.

BACKGROUND: Oxidative stress is the main cause of many diseases, but because of its complex pathogenic factors, there is no clear method for treating it. Ginseng total saponin (GTS) an important active ingredients in Panax ginseng C.A. Mey (PG) and has potential therapeutic ability for oxidative stress due to various causes. However, the molecular mechanism of GTS in the treating oxidative stress damage in red blood cells (RBCs) is still unclear. PURPOSE: This study aimed to examine the protective effect of GTS on RBCs under oxidative stress damage and to determine its potential mechanism. METHODS: The oxidative stress models of rat RBCs induced by hydrogen peroxide (H2O2) and exhaustive swimming in vivo and in vitro was used. We determined the cell morphology, oxygen carrying capacity, apoptosis, antioxidant capacity, and energy metabolism of RBCs. The effect of tyrosine phosphorylation (pTyr) of Band 3 protein on RBCs glycolysis was also examined. RESULTS: GTS reduced the hemolysis of RBCs induced by H2O2 at the lowest concentration. Moreover, GTS effectively improved the morphology, enhanced the oxygen carrying capacity, and increased antioxidant enzyme activity, adenosine triphosphate (ATP) levels, and adenosine triphosphatase (ATPase) activity in RBCs. GTS also promoted the expression of membrane proteins in RBCs, inhibited pTyr of Band 3 protein, and further improved glycolysis, restoring the morphological structure and physiological function of RBCs. CONCLUSIONS: This study shows, that GTS can protect RBCs from oxidative stress damage by improving RBCs morphology and physiological function. Changes in pTyr expression and its related pTyr regulatory enzymes before and after GTS treatment suggest that Band 3 protein is the main target of GTS in the treating endogenous and exogenous oxidative stress. Moreover, GTS can enhance the glycolytic ability of RBCs by inhibiting pTyr of Band 3 protein, thereby restoring the function of RBCs.

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.

Oral Exposure to Titanium Dioxide E171 and Zinc Oxide Nanoparticles Induces Multi-Organ Damage in Rats: Role of Ceramide.

Food-grade titanium dioxide (E171) and zinc oxide nanoparticles (ZnO NPs) are common food additives for human consumption. We examined multi-organ toxicity of both compounds on Wistar rats orally exposed for 90 days. Rats were divided into three groups: (1) control (saline solution), (2) E171-exposed, and (3) ZnO NPs-exposed. Histological examination was performed with hematoxylin-eosin (HE) staining and transmission electron microscopy (TEM). Ceramide (Cer), 3-nitrotyrosine (NT), and lysosome-associated membrane protein 2 (LAMP-2) were detected by immunofluorescence. Relevant histological changes were observed: disorganization, inflammatory cell infiltration, and mitochondrial damage. Increased levels of Cer, NT, and LAMP-2 were observed in the liver, kidney, and brain of E171- and ZnO NPs-exposed rats, and in rat hearts exposed to ZnO NPs. E171 up-regulated Cer and NT levels in the aorta and heart, while ZnO NPs up-regulated them in the aorta. Both NPs increased LAMP-2 expression in the intestine. In conclusion, chronic oral exposure to metallic NPs causes multi-organ injury, reflecting how these food additives pose a threat to human health. Our results suggest how complex interplay between ROS, Cer, LAMP-2, and NT may modulate organ function during NP damage.

Radiosynthesis and Preclinical Evaluation of m-[18F]FET and [18F]FET-OMe as Novel [18F]FET Analogs for Brain Tumor Imaging.

O-([18F]Fluoroethyl)-l-tyrosine ([18F]FET) is actively transported into the brain and cancer cells by LAT1 and possibly other amino acid transporters, which enables brain tumor imaging by positron emission tomography (PET). However, tumor delivery of this probe in the presence of competing amino acids may be limited by a relatively low affinity for LAT1. The aim of the present work was to evaluate the meta-substituted [18F]FET analog m-[18F]FET and the methyl ester [18F]FET-OMe, which were designed to improve tumor delivery by altering the physicochemical, pharmacokinetic, and/or transport properties. Both tracers could be prepared with good radiochemical yields of 41-56% within 66-90 min. Preclinical evaluation with [18F]FET as a reference tracer demonstrated reduced in vitro uptake of [18F]FET-OMe by U87 glioblastoma cells and no advantage for in vivo tumor imaging. In contrast, m-[18F]FET showed significantly improved in vitro uptake and accelerated in vivo tumor accumulation in an orthotopic glioblastoma model. As such, our work identifies m-[18F]FET as a promising alternative to [18F]FET for brain tumor imaging that deserves further evaluation with regard to its transport properties and in vivo biodistribution.

10-(6-Plastoquinonyl) decyltriphenylphosphonium imparts anti-colitogenic protection through recovery of mitochondrial dysfunction in ulcerated murine colon: Implications in ulcerative colitis.

AIMS: To elucidate the impact of 10-(6-plastoquinonyl) decyltriphenylphosphonium (SkQ1) as an anti-colitogenic agent for maintenance of colon epithelial tract in ulcerated mice through recovery of mitochondrial dysfunction and mitochondrial stress by virtue of its free radical scavenging properties. MAIN METHODS: DSS induced ulcerated BALB/c mice were treated with SkQ1 for 14 days @ 30 nmol/kg/body wt./day/mice. Post-treatment, isolated colonic mitochondria were utilized for spectrophotometric and spectrofluorometric biochemical analysis of various mitochondrial functional variables including individual mitochondrial respiratory enzyme complexes. Confocal microscopy was utilized for measuring mitochondrial membrane potential in vivo. ELISA technique was adapted for measuring colonic nitrite and 3-nitrotyrosine (3-NT) content. Finally in vitro cell line study was carried out to substantiate in vivo findings and elucidate the involvement of free radicals in UC using antioxidant/free radical scavenging regimen. KEY FINDINGS: Treatment with SkQ1 in vivo reduced histopathological severity of colitis, induced recovery of mitochondrial respiratory complex activities and associated functional variables, improved oxidative stress indices and normalized mitochondrial cardiolipin content. Importantly, SkQ1 lowered nitrite concentration and 3-nitrotyrosine formation in vivo. In vitro SkQ1 restored mitochondrial functions wherein the efficacy of SkQ1 proved equal or better compared to SOD and DMSO indicating predominant involvement of O2- and OH in UC. However, NO and ONOO- also seemed to play a secondary role as MEG and L-NAME provided lesser protection as compared to SOD and DMSO. SIGNIFICANCE: SkQ1 can be considered as a potent anti-colitogenic agent by virtue of its free radical scavenging properties in treating UC.

Misregulation of bromotyrosine compromises fertility in male Drosophila.

Biological regulation often depends on reversible reactions such as phosphorylation, acylation, methylation, and glycosylation, but rarely halogenation. A notable exception is the iodination and deiodination of thyroid hormones. Here, we report detection of bromotyrosine and its subsequent debromination during Drosophila spermatogenesis. Bromotyrosine is not evident when Drosophila express a native flavin-dependent dehalogenase that is homologous to the enzyme responsible for iodide salvage from iodotyrosine in mammals. Deletion or suppression of the dehalogenase-encoding condet (cdt) gene in Drosophila allows bromotyrosine to accumulate with no detectable chloro- or iodotyrosine. The presence of bromotyrosine in the cdt mutant males disrupts sperm individualization and results in decreased fertility. Transgenic expression of the cdt gene in late-staged germ cells rescues this defect and enhances tolerance of male flies to bromotyrosine. These results are consistent with reversible halogenation affecting Drosophila spermatogenesis in a process that had previously eluded metabolomic, proteomic, and genomic analyses.

Protein Tyrosine Amination: Detection, Imaging, and Chemoproteomic Profiling with Synthetic Probes.

Protein tyrosine nitration (PTN) by oxidative and nitrative stress is a well-known post-translational modification that plays a role in the initiation and progression of various diseases. Despite being recognized as a stable modification for decades, recent studies have suggested the existence of a reduction in PTN, leading to the formation of 3-aminotyrosine (3AT) and potential denitration processes. However, the vital functions of 3AT-containing proteins are still unclear due to the lack of selective probes that directly target the protein tyrosine amination. Here, we report a novel approach to label and enrich 3AT-containing proteins with synthetic salicylaldehyde (SAL)-based probes: SALc-FL with a fluorophore and SALc-Yn with an alkyne tag. These probes exhibit high selectivity and efficiency in labeling and can be used in cell lysates and live cells. More importantly, SALc-Yn offers versatility when integrated into multiple platforms by enabling proteome-wide quantitative profiling of cell nitration dynamics. Using SALc-Yn, 355 proteins were labeled, enriched, and identified to carry the 3AT modification in oxidatively stressed RAW264.7 cells. These findings provide compelling evidence supporting the involvement of 3AT as a critical intermediate in nitrated protein turnover. Moreover, our probes serve as powerful tools to investigate protein nitration and denitration processes, and the identification of 3AT-containing proteins contributes to our understanding of PTN dynamics and its implications in cellular redox biology.

Psammaplin A and Its Analogs Attenuate Oxidative Stress in Neuronal Cells through Peroxisome Proliferator-Activated Receptor γ Activation.

Psammaplins are sulfur containing bromotyrosine alkaloids that have shown antitumor activity through the inhibition of class I histone deacetylases (HDACs). The cytotoxic properties of psammaplin A (1), the parent compound, are related to peroxisome proliferator-activated receptor γ (PPARγ) activation, but the mechanism of action of its analogs psammaplin K (2) and bisaprasin (3) has not been elucidated. In this study, the protective effects against oxidative stress of compounds 1-3, isolated from the sponge Aplysinella rhax, were evaluated in SH-SY5Y cells. The compounds improved cell survival, recovered glutathione (GSH) content, and reduced reactive oxygen species (ROS) release at nanomolar concentrations. Psammaplins restored mitochondrial membrane potential by blocking mitochondrial permeability transition pore opening and reducing cyclophilin D expression. This effect was mediated by the capacity of 1-3 to activate PPARγ, enhancing gene expression of the antioxidant enzymes catalase, nuclear factor E2-related factor 2 (Nrf2), and glutathione peroxidase. Finally, HDAC3 activity was reduced by 1-3 under oxidative stress conditions. This work is the first description of the neuroprotective activity of 1 at low concentrations and the mechanism of action of 2 and 3. Moreover, it links for the first time the previously described effects of 1 in HDAC3 and PPARγ signaling, opening a new research field for the therapeutic potential of this compound family.

Preclinical evaluation of novel synthesised nanoparticles based on tyrosine poly(ester amide) for improved targeted pulmonary delivery.

Fixed dose combinations (FDCs) incorporating two or three medicines in a single inhaler have been created to enhance patient compliance and hence clinical outcomes. However, the development of dry powder inhalers (DPIs), particularly for FDCs, faces challenges pertinent to formulation uniformity and reproducibility. Therefore, this project aimed to employ nanotechnology to develop a FDC of DPIs for market-leading medicines-fluticasone propionate (FP) and salmeterol xinafoate (SAL)-for asthma management. Nanoaggregates were prepared using a novel biocompatible and biodegradable poly(ester amide) based on the amino acid tyrosine, utilising a one-step interfacial polymerisation process. The produced tyrosine poly (ester amide) drug-loaded nanoparticles were evaluated for content uniformity, PSA, FTIR, TEM, DSC, XRD and aerodynamic performance (in vitro and in vivo). The optimised formulation demonstrated high entrapment efficiency- > 90%. The aerodynamic performance in terms of the emitted dose, fine particle fraction and respirable dose was superior to the carrier-based marketed product. In-vivo studies showed that FP (above the marketed formulation) and SAL reached the lungs of mice in a reproducible manner. These results highlight the superiority of novel FDC FP/SAL nanoparticles prepared via a one-step process, which can be used as a cost-effective and efficient method to alleviate the burden of asthma.

Significance of nitrosative stress and glycoxidation products in the diagnosis of COVID-19.

Nitrosative stress promotes protein glycoxidation, and both processes can occur during an infection with the SARS-CoV-2 virus. Therefore, the aim of this study was to assess selected nitrosative stress parameters and protein glycoxidation products in COVID-19 patients and convalescents relative to healthy subjects, including in reference to the severity of COVID-19 symptoms. The diagnostic utility of nitrosative stress and protein glycoxidation biomarkers was also evaluated in COVID-19 patients. The study involved 218 patients with COVID-19, 69 convalescents, and 48 healthy subjects. Nitrosative stress parameters (NO, S-nitrosothiols, nitrotyrosine) and protein glycoxidation products (tryptophan, kynurenine, N-formylkynurenine, dityrosine, AGEs) were measured in the blood plasma or serum with the use of colorimetric/fluorometric methods. The levels of NO (p = 0.0480), S-nitrosothiols (p = 0.0004), nitrotyrosine (p = 0.0175), kynurenine (p < 0.0001), N-formylkynurenine (p < 0.0001), dityrosine (p < 0.0001), and AGEs (p < 0.0001) were significantly higher, whereas tryptophan fluorescence was significantly (p < 0.0001) lower in COVID-19 patients than in the control group. Significant differences in the analyzed parameters were observed in different stages of COVID-19. In turn, the concentrations of kynurenine (p < 0.0001), N-formylkynurenine (p < 0.0001), dityrosine (p < 0.0001), and AGEs (p < 0.0001) were significantly higher, whereas tryptophan levels were significantly (p < 0.0001) lower in convalescents than in healthy controls. The ROC analysis revealed that protein glycoxidation products can be useful for diagnosing infections with the SARS-CoV-2 virus because they differentiate COVID-19 patients (KN: sensitivity-91.20%, specificity-92.00%; NFK: sensitivity-92.37%, specificity-92.00%; AGEs: sensitivity-99,02%, specificity-100%) and convalescents (KN: sensitivity-82.22%, specificity-84.00%; NFK: sensitivity-82,86%, specificity-86,00%; DT: sensitivity-100%, specificity-100%; AGE: sensitivity-100%, specificity-100%) from healthy subjects with high sensitivity and specificity. Nitrosative stress and protein glycoxidation are intensified both during and after an infection with the SARS-CoV-2 virus. The levels of redox biomarkers fluctuate in different stages of the disease. Circulating biomarkers of nitrosative stress/protein glycoxidation have potential diagnostic utility in both COVID-19 patients and convalescents.

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.

Combining fecal 16 S rRNA sequencing and spinal cord metabolomics analysis to explain the modulatory effect of PPARα on neuropathic pain.

BACKGROUND: Existing evidence suggests that the composition of the gut microbiota is associated with neuropathic pain (NP), but the mechanistic link is elusive. Peroxisome proliferator-activated receptor α (PPARα) has been shown to be a pharmacological target for the treatment of metabolic disorders, and its expression is also involved in inflammatory regulation. The aim of this study was to investigate the important modulatory effects of PPARα on gut microbiota and spinal cord metabolites in mice subjected to chronic constriction injury. METHODS: We analyzed fecal microbiota and spinal cord metabolic alterations in mice from the sham, CCI, GW7647 (PPARα agonist) and GW6471 (PPARα antagonist) groups by 16 S rRNA amplicon sequencing and untargeted metabolomics analysis. On this basis, the intestinal microbiota and metabolites that were significantly altered between treatment groups were analyzed in a combined multiomics analysis. We also investigated the effect of PPARα on the polarization fractionation of spinal microglia. RESULTS: PPARα agonist significantly reduce paw withdrawal threshold and paw withdrawal thermal latency, while PPARα antagonist significantly increase paw withdrawal threshold and paw withdrawal thermal latency. 16 S rRNA gene sequencing showed that intraperitoneal injection of GW7647 or GW6471 significantly altered the abundance, homogeneity and composition of the gut microbiome. Analysis of the spinal cord metabolome showed that the levels of spinal cord metabolites were shifted after exposure to GW7647 or GW6471. Alterations in the composition of gut microbiota were significantly associated with the abundance of various spinal cord metabolites. The abundance of Licheniformes showed a significant positive correlation with nicotinamide, benzimidazole, eicosanoids, and pyridine abundance. Immunofluorescence results showed that intraperitoneal injection of GW7647 or GW6471 altered microglial activation and polarization levels. CONCLUSION: Our study shows that PPARα can promote M2-type microglia polarization, as well as alter gut microbiota and metabolites in CCI mice. This study enhances our understanding of the mechanism of PPARα in the treatment of neuropathic pain.

N-oleoyl alanine attenuates nicotine reward and spontaneous nicotine withdrawal in mice.

BACKGROUND: As nicotine dependence represents a longstanding major public health issue, new nicotine cessation pharmacotherapies are needed. Administration of N-oleoyl glycine (OlGly), an endogenous lipid signaling molecule, prevents nicotine-induced conditioned place preference (CPP) through a peroxisome proliferator-activated receptor-alpha (PPARα) dependent mechanism, and also ameliorated withdrawal signs in nicotine-dependent mice. Pharmacological evidence suggests that the methylated analog of OlGly, N-oleoyl alanine (OlAla), has an increased duration of action and may offer translational benefit. Accordingly, OlAla was assessed in nicotine CPP and dependence assays as well as its pharmacokinetics compared to OlGly. METHODS: ICR female and male mice were tested in nicotine-induced CPP with and without the PPARα antagonist GW6471. OlAla was also assessed in nicotine-dependent mice following removal of nicotine minipumps: somatic withdrawal signs, thermal hyper-nociception and altered affective behavior (i.e., light/dark box). Finally, plasma and brain were collected after administration of OlGly or OlAla and analyzed by high-performance liquid chromatography tandem mass spectrometry. RESULTS: OlAla prevented nicotine-induced CPP, but this effect was not blocked by GW6471. OlAla attenuated somatic and affective nicotine withdrawal signs, but not thermal hyper-nociception in nicotine-dependent mice undergoing withdrawal. OlAla and OlGly showed similar time-courses in plasma and brain. CONCLUSIONS: The observation that both molecules showed similar pharmacokinetics argues against the notion that OlAla offers increased metabolic stability. Moreover, while these structurally similar lipids show efficacy in mouse models of reward and dependence, they reduce nicotine reward through distinct mechanisms.

Effects of Dityrosine on Lactic Acid Metabolism in Mice Gastrocnemius Muscle During Endurance Exercise via the Oxidative Stress-Induced Mitochondria Damage.

Dityrosine (Dityr) has been detected in commercial food as a product of protein oxidation and has been shown to pose a threat to human health. This study aims to investigate whether Dityr causes a decrease in lactic acid metabolism in the gastrocnemius muscle during endurance exercise. C57BL/6 mice were administered Dityr or saline by gavage for 13 weeks and underwent an endurance exercise test on a treadmill. Dityr caused a severe reduction in motion displacement and endurance time, along with a significant increase in lactic acid accumulation in the blood and gastrocnemius muscle in mice after exercise. Dityr induced significant mitochondrial defects in the gastrocnemius muscle of mice. Additionally, Dityr induced serious oxidative stress in the gastrocnemius muscle, accompanied by inflammation, which might be one of the causes of mitochondrial dysfunction. Moreover, significant apoptosis in the gastrocnemius muscle increased after exposure to Dityr. This study confirmed that Dityr induced oxidative stress in the gastrocnemius muscle, which further caused significant mitochondrial damage in the gastrocnemius muscle cell, resulting in decreased capacity of lactic acid metabolism and finally affected performance in endurance exercise. This may be one of the possible mechanisms by which highly oxidized foods cause a decreased muscle energy metabolism.

Marine Bromotyrosine Derivatives in Spotlight: Bringing Discoveries and Biological Significance.

The Verongida order comprises several sponge families, such as Aplysinellidae, Aplysinidae, Ianthellidae, and Pseudoceratinidae, reported for producing bromotyrosine-derived compounds. First identified in 1913, bromotyrosine derivatives have since captivated interest notably for their antitumor and antimicrobial properties. To date, over 360 bromotyrosine derivatives have been reported. Our review focuses specifically on bromotyrosine derivatives newly reported from 2004 to 2023, by summarizing current knowledge about their chemical diversity and their biological activities.

[18F]FET PET/MRI: An Accurate Technique for Detection of Small Functional Pituitary Tumors.

Small functional pituitary tumors can cause severely disabling symptoms and early death. The gold standard diagnostic approach includes laboratory tests and MRI, with or without inferior petrosal sinus sampling (IPSS). In up to 40% of patients, however, the source of excess hormone production remains unidentified or uncertain. This excludes patients from surgical, Gamma Knife, and CyberKnife therapy and adversely affects overall cure rates. We here assess the diagnostic yield of O-(2-[18F]fluoroethyl)-l-tyrosine ([18F]FET) PET/MRI for detection of small functional pituitary tumors in these patients. Methods: This retrospective analysis included patients with Cushing disease (CD) but prior negative or inconclusive MRI results who underwent [18F]FET PET/MRI between February 1, 2021, and December 1, 2022. PET/MR images and MR images alone were evaluated by experienced nuclear radiologists, neuroradiologists, or radiologists. Postoperative tissue analysis (when performed) was used as a reference standard to assess diagnostic metrics (i.e., sensitivity and positive predictive value). Results were also compared with previously obtained MR images, preceding IPSS, and clinical or biochemical follow-up. Results: Twenty-two patients (68% female; mean age ± SD, 48 ± 15 y; range, 24-68 y) were scanned. All patients showed a clear metabolic focus on [18F]FET PET, whereas reading of the MRI alone yielded a suspected lesion in only 50%. Fifteen patients underwent surgery directed at the [18F]FET-positive focus. Tissue analysis confirmed a pituitary adenoma/pituitary neuroendocrine tumor of the corticotroph cell type (TPIT lineage) in 10 of 15 and a pituicytoma in 1 of 15, rendering a sensitivity of 100% and a positive predictive value of 73%. Lateralization was more accurate with [18F]FET PET/MRI than with IPSS in 33%. Twelve of 16 (75%) patients who received surgical, Gamma Knife, or CyberKnife therapy after [18F]FET PET/MRI reached short-term remission. Conclusion: [18F]FET PET/MRI shows a high diagnostic yield for localizing small functional pituitary tumors. This multimodal imaging technique provides a welcome improvement for diagnosis, planning of surgery, and clinical outcome in patients with Cushing disease, particularly those with repeated negative or inconclusive MRI results with or without IPSS.

Development of a selective electrochemical microsensor based on molecularly imprinted polydopamine/ZIF-67/laser-induced graphene for point-of-care determination of 3-nitrotyrosine.

3-nitrotyrosine (3-NT) is a biomarker closely associated with the early diagnosis of oxidative stress-related disorders. The development of an accurate, cost-effective, point-of-care 3-NT sensor holds significant importance for self-monitoring and clinical treatment. In this study, a selective, sensitive, and portable molecularly imprinted electrochemical sensor was developed. ZIF-67 with strong adsorption capacity was facilely modified on an electrochemically active laser-induced graphene (LIG) substrate (formed ZIF-67/LIG). Subsequently, biocompatible dopamine was chosen as the functional monomer, and interference-free ʟ-tyrosine was used as the dummy template to create molecularly imprinted polydopamine (MIPDA) on the ZIF-67/LIG, endowing the sensor with selectivity. The morphologies, electrochemical properties, and detection performance of the sensor were comprehensively investigated using scanning electron microscopy, cyclic voltammetry, electrochemical impedance spectroscopy, and differential pulse voltammetry. To achieve the best performance, several parameters were optimized, including the number of polymerization cycles (15), elution time (60 min), incubation time (7 min), and pH of the buffer solution (6). The turnaround time for this sensor is 10 min. Benefiting from the alliance of MIPDA, ZIF-67, and LIG, the sensor exhibited excellent sensitivity with a detection limit of 6.71 nM, and distinguished selectivity against 11 interfering substances. To enable convenient clinical diagnosis, a customized electrochemical microsensor with MIPDA/ZIF-67/LIG was designed, showcasing excellent reliability and convenience in detecting biological samples without pretreatment. The proposed microsensor will not only facilitate clinical diagnosis and improve patient care, but also provide inspiration for the development of other portable and accurate electrochemical biosensors.

Engineered dityrosine-bonding of the RSV prefusion F protein imparts stability and potency advantages.

Viral fusion proteins facilitate cellular infection by fusing viral and cellular membranes, which involves dramatic transitions from their pre- to postfusion conformations. These proteins are among the most protective viral immunogens, but they are metastable which often makes them intractable as subunit vaccine targets. Adapting a natural enzymatic reaction, we harness the structural rigidity that targeted dityrosine crosslinks impart to covalently stabilize fusion proteins in their native conformations. We show that the prefusion conformation of respiratory syncytial virus fusion protein can be stabilized with two engineered dityrosine crosslinks (DT-preF), markedly improving its stability and shelf-life. Furthermore, it has 11X greater potency as compared with the DS-Cav1 stabilized prefusion F protein in immunogenicity studies and overcomes immunosenescence in mice with simply a high-dose formulation on alum.

Verification of chlorine exposure via LC-MS/MS analysis of base hydrolyzed chlorophenols from chlorotyrosine-protein adducts.

Inhalation of chlorine gas, with subsequent hydrolysis in the airway and lungs to form hydrochloric acid (HCl) and hypochlorous acid (HOCl), can cause pulmonary edema (i.e., fluid build-up in the lungs), pulmonary inflammation (with or without infection), respiratory failure, and death. The HOCl produced from chlorine is known to react with tyrosine to form adducts via electrophilic aromatic substitution, resulting in 3-chlorotyrosine and 3,5-dichlorotyrosine adducts. While several analysis methods are available for determining these adducts, each method has significant disadvantages. Hence, a simple and sensitive ultra-high performance liquid chromatography-tandem mass spectroscopy (UHPLC-MS/MS) method was developed for the determination of chlorotyrosine adducts. The sample preparation involves base hydrolysis of isolated plasma proteins to form 2-chlorophenol (CP) from monochlorotyrosine adducts and 2,6-dichlorophenol (2,6-DCP), from dichlorotyrosine adducts, as markers of chlorine exposure. The chlorophenols are extracted with cyclohexane prior to UHPLC-MS/MS analysis. The method produced excellent sensitivity for 2,6-DCP with a limit of detection of 2.2 µg/kg, calibration curve linearity extending from 0.054-54 mg/kg (R2 ≥ 0.9997 and %RA > 94), and accuracy and precision of 100 ± 14 %, and <15 % relative standard deviation, respectively. The sensitivity of the method for 2-CP was relatively poor, so it was used only as a secondary marker for severe chlorine exposure. The method successfully detected elevated levels of 2,6-DCP from hypochlorite-spiked plasma protein and plasma protein isolated from chlorine-exposed rats.

MXene nanosheet-derived N, S-codoped graphene quantum dots for ultrasensitive and selective detection of 3-nitro-l-tyrosine in human serum.

3-Nitro-l-tyrosine (3NT) is an oxidative stress metabolite associated with neurodegenerative diseases such as Parkinson's disease and rheumatoid arthritis. In this study, the N, S-co-doped graphene quantum dots (NSGQDs) derived from nitrogen-doped Ti3C2Tx MXene nanosheet via the hydrothermal method in the presence of mercaptosuccinic acid was synthesized as an optical sensing probe to detect 3NT in human serum. Tetramethyl ammonium hydroxide, the nitrogen source and delamination agent, was used to prepare nitrogen-doped MXene nanosheets via one step at room temperature. The as-prepared NSGQDs are uniform with an average size of 1.2 ± 0.6 nm, and can be stable in aqueous solution for at least 90 d to serve as the fluorescence probe. The N atoms in N-MXene reduce the restacking and aggregation of MXene nanosheets, while the sulfur dopant in NSGQDs increases the quantum yield from 6.2 to 12.1 % as well as enhances the selectivity of 3NT over the other 12 interferences via coordination interaction with nitro group in 3NT. A linear range of 0.02-150 µM in PBS and 0.05-200 µM in human serum with a recovery of 97-108 % for 3NT detection is observed. Moreover, the limit of detection can be lowered to 4.2 and 7 nM in PBS and 1 × diluted human serum, respectively. Results obtained clearly indicate the potential application of the N-Ti3C2Tx derived NSGQD for effective detection of 3NT, which can open a window for the synthesis of doped GQDs via 2D MXene materials for ultrasensitive and selective detection of other biometabolites and biomarkers of neurodegenerative diseases in biological fluids.