Background: There has been an increased prevalence of positive patch test reactions to propolis in recent years. Different reaction rates have been described when using propolis supplied by different manufacturers. Objective: Compare compositions of Brazilian propolis prepared by Allergeaze and Chinese propolis prepared by Chemotechnique. Methods: Both samples were analyzed using electrospray ionization mass spectrometry, and compounds were identified via the mzCloud, ChemSpider, and MassList databases. Data processing with Compound Discoverer software identified the top 6 compounds based on relative abundance. Results: A very low compositional overlap between the 2 propolis types: 8% match with ChemSpider, 9% with MassList, and 27% with mzCloud. The six most abundant compounds in Brazilian propolis included lauryldimethylamine oxide, (9Z)-9-octadecenamide, trioctylmethylammonium cation, monocillin VI and istamycin C1, while Chinese propolis contained pinocembrin, 16-([ethylcarbamoyl]amino) hexadecanoic acid, (4E)-6-hydroxy-4-octadecenoic acid/bee glue, linoleamide, and MFCD00083068. Prenylgermacrene B was the only common compound in both samples' top 6. Conclusion: These findings highlight significant compositional differences between Brazilian and Chinese propolis. Chinese propolis (catalog number NA71) was discontinued by Allergeaze in October 2019 and replaced by Brazilian propolis (catalog number NH400), likely contributing to the increased prevalence of positive reactions in recent years.

Changes in metabolic activity are key regulators of macrophage activity. Proinflammatory macrophages upregulate glycolysis, which promotes an inflammatory phenotype, whereas prorepair macrophages rely on oxidative metabolism and glutaminolysis to support their activity. Work to understand how metabolism regulates macrophage phenotype has been done primarily in macrophage cell lines and bone marrow-derived macrophages (BMDM). Our study sought to understand changes in metabolic activity of murine tissue-resident alveolar macrophages (AM) in response to LPS stimulation and to contrast them to BMDM. These studies also determined the contribution of glutamine metabolism using the glutamine inhibitor, 6-diazo-5-oxo-L-norleucine (DON). We found that compared with BMDM, AM have higher rates of oxygen consumption and contain a higher concentration of intracellular metabolites involved in fatty acid oxidation. In response to LPS, BMDM, but not AM, increased rates of glycolysis. Inhibition of glutamine metabolism using DON altered the metabolic activity of AM but not BMDM. Within AM, glutamine inhibition led to increases in intracellular metabolites involved in glycolysis, the tricarboxylic acid (TCA) cycle, fatty acid oxidation, and amino acid metabolism. Glutamine inhibition also altered the metabolic response to LPS within AM but not BMDM. Our data reveal striking differences in the metabolic activity of AM and BMDM.

Melatonin vaping products, touted for their faster absorption than oral melatonin supplements, have been gaining popularity among adolescents as sleep aid. Here, we elucidated the response of human bronchial epithelial cells (hBECs) to high levels of melatonin from vaped aerosols, investigated the uptake of melatonin by hBECs in vitro, and characterized the chemical composition of three commercially available melatonin vapes. Melatonin vape exposure decreased the secretion of chemokines and produced an immunosuppressive gene expression signature. The tested devices contained potential contaminants, including pharmaceuticals and industrial chemicals. Further investigation is needed for melatonin vapes to determine their local and systemic toxicity.

Background: Sickle cell anemia (SCA) is associated with an increased risk of chronic kidney disease (CKD), which presents in its early stages as persistent albuminuria (PA). Understanding metabolic alterations underlying PA may aid diagnosis, prognosis, and management. This study aimed to identify disease-specific metabolites and associated biological pathways linked to PA in SCA using plasma metabolomics. Methods: Untargeted metabolomics analysis of 280 SCA patients was performed using liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS). PA was defined based on urine albumin-creatinine ratio (UACR) ≥30 mg/g at least twice over 6 months or UACR ≥100 mg/g, if only one value was available. Data were preprocessed by quantile normalization, log10 transformation and auto-scaling. Differentially expressed metabolites (DEMs) between PA and those without PA were extracted using the linear model framework of R′s limma package with adjusted p≤0.05 for multiple tests. Pathway analysis was conducted to identify biological pathways enriched in DEMs. To assess predictive power of DEMs and their ability to predict PA, we performed machine learning with an Xtreme Gradient Boosting (XGBoost) model, which builds sequential decision trees, where each tree aims to correct errors of previous trees. We applied hyperparameter tuning to optimize model performance. A grid search-based approach was utilized to identify top metabolites contributing to model predictions, and 5-fold cross-validation for model evaluation. Model performance was assessed with area under the receiver operating characteristics (AUROC), sensitivity and specificity and their standard deviations. Results: Of 280 patients, 161 (57.5%) were female; 100 (35.7%) had PA. Metabolomic analysis revealed 52 differentially expressed metabolites in patients with PA vs. those without PA. Significant alterations were observed in several metabolic pathways, including tryptophan, nicotinate and nicotinamide, histidine, glycine and serine metabolism and bile acid biosynthesis. Among specific metabolites, hydroxypropionylcarnitine, C4-Carnitine, O-[(2E)-hexenedioyl] carnitine and Tetranor-12R-HETE, kynurenic acid, quinolinic acid, methylhistamine and phosphohydroxypyruvic acid differentiated SCA patients with PA from those without PA. Cross-validation of the XGBoost model with the top 18 metabolites yielded an AUROC of 0.75 (±0.07), sensitivity of 0.81 (±0.05), and specificity of 0.55 (±0.14). Conclusions: Tryptophan metabolism, particularly via the kynurenine pathway, is linked to inflammation and oxidative stress, key factors in CKD pathophysiology. Impaired NAD+ metabolism exacerbates oxidative stress and inflammation, impacting kidney function. Altered levels of methylhistamine reflect heightened immune activity and inflammation, contributing to kidney damage. Imbalances in glycine and serine metabolism are part of one-carbon metabolism with altered phosphohydroxypyruvic acid levels, an intermediate in serine biosynthesis, and suggest disruptions in serine and glycine metabolism in CKD. Bile acids exert inflammatory and fibrotic effects on the kidneys. Elevated carnitine derivatives indicate disruptions in fatty acid metabolism and mitochondrial oxidation, contributing to oxidative stress and kidney injury. This metabolic dysregulation can lead to reduced energy production and increased oxidative stress in renal cells, contributing to cellular injury and dysfunction. Collectively, these metabolites highlight the complex metabolic disruptions associated with PA in SCA. Alterations in these metabolic pathways may contribute to development and progression of CKD through inflammation, oxidative stress and disruptions in cellular metabolism. Understanding these relationships and mechanistic roles of these metabolites will enhance our ability to predict, monitor, and treat kidney disease in SCA. XGBoost model achieved an optimal AUROC utilizing 18 metabolites, indicating good discriminatory power between patients with PA and those without PA. The model showed a high sensitivity, but a moderate specificity, suggesting that it effectively identifies patients with PA but may produce false positives. Future work should focus on model optimization to improve specificity while maintaining sensitivity and external validation in an independent dataset.

Rhabdomyolysis is a clinical emergency characterized by severe muscle damage, resulting in the release of intracellular muscle components, which leads to myoglobinuria and, in severe cases, acute kidney failure. Rhabdomyolysis is caused by genetic factors linked to increased disease susceptibility in response to extrinsic triggers. Recessive mutations in TANGO2 result in episodic rhabdomyolysis, metabolic crises, encephalopathy and cardiac arrhythmia. The underlying mechanism contributing to disease onset in response to specific triggers remains unclear. To address these challenges, we created a zebrafish model of Tango2 deficiency. Here, we demonstrate that the loss of Tango2 in zebrafish results in growth defects, early lethality and increased susceptibility of skeletal muscle defects in response to extrinsic triggers, similar to TANGO2-deficient patients. Using lipidomics, we identified alterations in the glycerolipid pathway in tango2 mutants, which is critical for membrane stability and energy balance. Therefore, these studies provide insight into key disease processes in Tango2 deficiency and have increased our understanding of the impacts of specific defects on predisposition to environmental triggers in TANGO2-related disorders.

Damage associated molecular patterns (DAMPs) are molecules released from dead/dying cells following toxicant and/or environmental exposures that activate the immune response through binding of pattern recognition receptors (PRRs). Excessive production of DAMPs or failed clearance leads to chronic inflammation and delayed inflammation resolution. One category of DAMPs are oxidized phospholipids (oxPLs) produced upon exposure to high levels of oxidative stress, such as following ozone (O3) induced inflammation. OxPLs are bound by multiple classes of PRRs that include scavenger receptors (SRs) such as SR class B-1 (SR-BI) and toll-like receptors (TLRs). Interactions between oxPLs and PRRs appear to regulate inflammation; however, the role of SR-BI in oxPL-induced lung inflammation has not been defined. Therefore, we hypothesize that SR-BI is critical in protecting the lung from oxPL-induced pulmonary inflammation/injury. To test this hypothesis, C57BL/6J (WT) female mice were dosed with oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphatidylcholine (oxPAPC) by oropharyngeal aspiration which increased pulmonary SR-BI expression. Following oxPAPC exposure, SR-BI deficient (SR-BI−/−) mice exhibited increased lung pathology and inflammatory cytokine/chemokine production. Lipidomic analysis revealed that SR-BI−/− mice had an altered pulmonary lipidome prior to and following oxPAPC exposure, which correlated with increased oxidized phosphatidylcholines (PCs). Finally, we characterized TLR4-mediated activation of NF-κB following oxPAPC exposure and discovered that SR-BI−/− mice had increased TLR4 mRNA expression in lung tissue and macrophages, increased nuclear p65, and decreased cytoplasmic IκBα. Overall, we conclude that SR-BI is required for limiting oxPAPC-induced lung pathology by maintaining lipid homeostasis, reducing oxidized PCs, and attenuating TLR4-NF-κB activation, thereby preventing excessive and persistent inflammation.

Introduction: Longitudinal effect of diet-induced obesity on bone is uncertain. Prior work showed both no effect and a decrement in bone density or quality when obesity begins prior to skeletal maturity. We aimed to quantify long-term effects of obesity on bone and bone marrow adipose tissue (BMAT) in adulthood. Methods: Skeletally mature, female C57BL/6 mice (n = 70) aged 12 weeks were randomly allocated to low-fat diet (LFD; 10% kcal fat; n = 30) or high-fat diet (HFD; 60% kcal fat; n = 30), with analyses at 12, 15, 18, and 24 weeks (n = 10/group). Tibial microarchitecture was analyzed by µCT, and volumetric BMAT was quantified via 9.4T MRI/advanced image analysis. Histomorphometry of adipocytes and osteoclasts, and qPCR were performed. Results: Body weight and visceral white adipose tissue accumulated in response to HFD started in adulthood. Trabecular bone parameters declined with advancing experimental age. BV/TV declined 22% in LFD (p = 0.0001) and 17% in HFD (p = 0.0022) by 24 weeks. HFD failed to appreciably alter BV/TV and had negligible impact on other microarchitecture parameters. Both dietary intervention and age accounted for variance in BMAT, with regional differences: distal femoral BMAT was more responsive to diet, while proximal femoral BMAT was more attenuated by age. BMAT increased 60% in the distal metaphysis in HFD at 18 and 24 weeks (p = 0.0011). BMAT in the proximal femoral diaphysis, unchanged by diet, decreased 45% due to age (p = 0.0002). Marrow adipocyte size via histomorphometry supported MRI quantification. Osteoclast number did not differ between groups. Tibial qPCR showed attenuation of some adipose, metabolism, and bone genes. A regulator of fatty acid β-oxidation, cytochrome C (CYCS), was 500% more abundant in HFD bone (p < 0.0001; diet effect). CYCS also increased due to age, but to a lesser extent. HFD mildly increased OCN, TRAP, and SOST. Conclusions: Long-term high fat feeding after skeletal maturity, despite upregulation of visceral adiposity, body weight, and BMAT, failed to attenuate bone microarchitecture. In adulthood, we found aging to be a more potent regulator of microarchitecture than diet-induced obesity.

Pain intensity is well-known to be influenced by a wide range of biobehavioral variables. Nutritional factors, however, have not been generally considered for their potential importance. This cross-sectional study examined associations between erythrocyte omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids (PUFAs) and pain intensity in 605 adults. Pain intensity was com-puted on a 0 to 100 numeric rating scale from questions about 5 chronic pain conditions: orofacial pain, headache, low back pain, irritable bowel syndrome, and bodily pain. For each pain condition, multiple linear regression tested the hypothesis that a higher ratio of n-6 arachidonic acid to the sum of n-3 eicosapentaenoic acid and docosahexaenoic acid (AA/(EPA+DHA) was associated with greater pain intensity. In covariate-adjusted analysis, orofacial pain intensity increased 5.7 points (95% CI: 1.4, 9.9) per unit increase in n-6/n-3 PUFA ratio. Likewise, a 1 unit increase in n-6/n-3 PUFA ratio was associated with significant increases in pain intensity (range 5-8 points) of headache pain, low back pain, and bodily pain, but not abdominal pain. Separate multiple linear regression models investigated the independent strength of association of individual PUFAs to the intensity of each pain condition. Overall, n-3 docosahexaenoic acid was most strongly, and inversely, associated with pain intensity.Perspective: A higher ratio of n-6/n-3 long-chain polyunsaturated fatty acids was associated greater pain intensity for orofacial pain, headache, low back pain, and bodily pain, but not abdominal pain. The n-6/n-3 PUFA ratio was more consistently associated with pain intensity than any individual constituent of the long-chain PUFA ratio.(c) Published by Elsevier Inc. on behalf of United States Association for the Study of Pain, Inc.

OBJECTIVE:This study investigated whether non-esterified erythrocyte omega-6 PUFAs were associated with subjective assessment of sleep quality and duration, and risk for obstructive sleep apnea.METHODS:In this secondary analysis of the cross-sectional OPPERA-II study, 538 adults completed the Pittsburgh Sleep Quality Index (PSQI), reported their usual hours of sleep, and answered STOP screening questions for obstructive sleep apnea. Circulating non-esterified erythrocyte concentrations of omega-6 PUFA linoleic acid and arachidonic acid were quantified by liquid chromatography tandem mass spectroscopy. Sleep outcomes were dichotomized as poor (PSQI ≤5) vs good (PSQI ≥6) sleep quality, insufficient or excessive (≤6 or >9 h) vs good (7-9 h) sleep duration, and high (≥2 affirmative responses) vs low (<2 affirmative responses) risk for obstructive sleep apnea. Non-esterified omega-6 PUFAs and the continuous covariates of body mass index, Short Form (SF) 12 Health Survey Physical and Mental Component scores and resting measures of systolic and diastolic blood pressure were standardized for multivariable analysis. Categorical covariates were study site, age, sex, and race/ethnicity. Multivariable-adjusted logistic regression first estimated odds ratios (OR) and 95% confidence limits (CL) for sleep outcomes using linoleic acid as the main exposure. Analysis was then repeated using arachidonic acid as the main exposure.RESULTS:In the multivariable-adjusted model, each standard deviation increase in non-esterified erythrocyte linoleic acid was associated with higher odds of poor sleep quality (OR=1.2, 95% CL: 1.1, 1.5), insufficient or excessive sleep (OR= 1.3, 95% CL: 1.1, 1.6) and high-risk for obstructive sleep apnea (OR=1.3, 95% CL: 1.1, 1.6). Likewise, for each standard deviation increase in non-esterified erythrocyte arachidonic acid, odds increased of poor sleep quality (OR=1.2, 95% CL: 1.1, 1.5), and insufficient or excessive sleep (OR=1.2, 95% CL: 1.1, 1.5). Odds of being high risk for obstructive sleep apnea increased with greater circulating arachidonic acid, but the association did not reach statistical significance (OR=1.1, 95% CL: 0.9, 1.4).CONCLUSION:Non-esterified erythrocyte linoleic acid and arachidonic acid were associated with poor sleep quality and insufficient or excessive sleep duration. Linoleic acid, but not arachidonic acid, was also associated with high risk for obstructive sleep apnea.

Somatic symptom disturbance is among the strongest predictors of painful temporomandibular disorder (TMD). Related psychological constructs, such as anxiety and depression, respond therapeutically to omega-3 polyunsaturated fatty acids (PUFAs) in clinical trials. This cross-sectional study investigated associations between the omega-6/omega-3 PUFA ratio and somatic symptom disturbance and depressive symptoms in a community-based sample of 501 adults and determined whether these associations differed between adults with and without TMD or irritable bowel syndrome (IBS). Liquid chromatography tandem mass spectrometry quantified PUFAs in circulating erythrocytes. Somatic symptoms and depression were quantified using Symptom Checklist-90-Revised subscales. Presence or absence of TMD and IBS, respectively, were determined by clinical examination and Rome III screening questions. The standardized beta coefficient for the omega-6/omega-3 long-chain PUFA ratio was 0.26 (95% confidence limits (CL): 0.08, 0.43) in a multivariable linear regression model in which somatic symptom disturbance was the dependent variable. When modelling depressive symptoms as the dependent variable, the standardized beta coefficient was 0.17 (95% CL:0.01, 0.34). Both associations were stronger among TMD cases and IBS cases than among non-cases. Future randomized control trials that lower the omega-6/omega-3 PUFA ratio could consider somatic or depressive symptoms as a therapeutic target for TMD or IBS pain. PERSPECTIVE: In people with TMD or IBS, a high n-6/n-3 PUFA ratio was positively associated with somatic symptom disturbance and depressive symptoms. Both measures of psychological distress were elevated in people with painful TMD and IBS. Future randomized clinical trials will determine whether lowering the n-6/n-3 ratio is therapeutic for pain.

Preclinical studies demonstrate opposing effects of long-chain polyunsaturated fatty acid (PUFA) metabolites on inflammation and nociception. Omega-6 (n-6) PUFAs amplify both processes while omega-3 (n-3) PUFAs inhibit them. This cross-sectional study examined relationships between PUFAs in circulating erythrocytes and 2 chronic idiopathic pain conditions: temporomandibular disor-der (TMD) and low back pain in a community-based sample of 503 U.S. adults. Presence or absence of TMD and low back pain, respectively, were determined by clinical examination and by responses to established screening questions. Liquid chromatography-tandem mass spectrometry quantified PUFAs. In multivariable logistic regression models, a higher ratio of n-6/n-3 long-chain PUFAs was associated with greater odds of TMD (odds ratio ((OR) = 1.75, 95% confidence limits (CL): 1.16, 2.64) and low back pain (OR = 1.63, 95% CL: 1.07, 2.49). Higher levels of the pronociceptive n-6 long-chain arachidonic acid (AA) were associated with a greater probability of both pain conditions for women, but not men. Higher levels of the antinociceptive long-chain n-3 PUFAs eicosapentaenoic and docosa-hexaenoic acids were associated with a lower probability of both pain conditions for men, but not women. As systemic inflammation is not a hallmark of these conditions, PUFAs may influence idio-pathic pain through other mechanisms. Perspective: This cross-sectional clinical study found that a higher ratio of circulating n-6/n-3 long -chain PUFAs was associated with greater odds of 2 common chronic overlapping pain conditions. This suggests that the pro and antinociceptive properties of n-6 and n-3 PUFAs, respectively, influence pain independently of their well-established inflammatory pathways.(c) Published by Elsevier Inc. on behalf of United States Association for the Study of Pain, Inc.

Circulating polyunsaturated fatty acids (PUFAs) and lipid mediators were extracted from human red blood cells and quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method encompassed 13 different PUFAs and lipid mediators, however, due to instrument capability only five were confidently quantified (EPA, ALA, AA, DHA, and LA). The extraction focused on free polyunsaturated fatty acids since they have a strong correlation with health in humans. The study design was a secondary analysis of the OPPERA-2 study of chronic overlapping pain conditions in adults. The data included are: a) raw LC-MS/MS data (.raw); b) processed data (.xlsx) including chromatographic peak area for each compound and a concentration (ng/mL) based on external calibration with internal standardization using pure analytical grade standards and heavy-isotope labeled internal standards; c) study participant demographics and phenotypes (.xlsx). This dataset consisting of circulating PUFA quantities measured in 605 humans has been made publicly available for analysis and interpretation.

Obesity exacerbates inflammation upon lung injury; however, the mechanisms by which obesity primes pulmonary dysregulation prior to external injury are not well studied. Herein, we tested the hypothesis that obesity dysregulates pulmonary PUFA metabolism that is central to inflammation initiation and resolution. We first show that a high-fat diet (HFD) administered to C57BL/6J mice increased the relative abundance of pulmonary PUFA-containing triglycerides and the concentration of PUFA-derived oxylipins (particularly prostaglandins and hydroxyeicosatetraenoic acids), independent of an increase in total pulmonary PUFAs, prior to onset of pulmonary inflammation. Experiments with a genetic model of obesity (ob/ob) generally recapitulated the effects of the HFD on the pulmonary oxylipin signature. Subsequent pulmonary next-generation RNA sequencing identified complex and unique transcriptional regulation with the HFD. We found the HFD increased pathways related to glycerophospholipid metabolism and immunity, including a unique elevation in B cell differentiation and signaling. Furthermore, we conducted computational integration of lipidomic with transcriptomic data. These analyses identified novel HFD-driven networks between glycerophospholipid metabolism and B cell receptor signaling with specific PUFA-derived pulmonary oxylipins. Finally, we confirmed the hypothesis by demonstrating that the concentration of pulmonary oxylipins, in addition to inflammatory markers, were generally increased in mice consuming a HFD upon ozone-induced acute lung injury. Collectively, these data show that a HFD dysregulates pulmonary PUFA metabolism prior to external lung injury, which may be a mechanism by which obesity primes the lungs to respond poorly to infectious and/or inflammatory challenges.

OBJECTIVE:Polyunsaturated fatty acids (PUFAs) play a role in pain regulation. This study sought to determine whether free PUFAs found in red blood cells also play a role in nociceptive processing. We examined associations between circulating PUFAs and nociceptive thresholds to noxious mechanical stimuli. We also determined whether nociceptive thresholds were associated with nociplastic pain conditions.METHODS:This cross-sectional study used stored red bloods cells and data from 605 adult participants in the OPPERA-2 study of chronic overlapping pain conditions. In OPPERA-2 adults completed quantitative sensory testing in which pressure algometry measured deep muscular tissue sensitivity at six anatomical sites. Standardized protocols classified adults for presence or absence of five nociplastic pain conditions: temporomandibular disorder, headache, low back pain, irritable bowel syndrome and fibromyalgia. Liquid chromatography tandem mass spectroscopy quantified erythrocyte PUFAs. We conducted three sets of analyses. First, a multivariable linear regression model assessed the association between n-6/n-3 PUFA ratio and the number of overlapping nociplastic pain conditions. Second, a series of 36 multivariable linear regression models assessed covariate-adjusted associations between PUFAs and nociceptive thresholds at each of six anatomical sites. Third, a series of 30 multivariable linear regression models assessed covariate-adjusted associations between nociceptive thresholds at six anatomical sites and each of five pain conditions.RESULTS:In multiple linear regression, each unit increase in n-6/n-3 PUFA ratio was associated with more pain conditions (β = 0.30, 95% confidence limits: 0.07, 0.53, p = 0.012). Omega-6 linoleic acid and arachidonic acid were negatively associated with lower nociceptive thresholds at three and at five, respectively, anatomical sites. In contrast, omega-3 alpha-linolenic acid, eicosapentaenoic acid, docosahexaenoic acid and the n-6/n-3 PUFA ratio were not associated with nociceptive thresholds at any site. Pain cases had significantly lower nociceptive thresholds than non-case controls at all anatomical sites.CONCLUSION:A higher n-6/n-3 PUFA ratio was associated with more pain conditions. Omega-6 PUFAs may promote a generalized upregulation of nociceptive processing.

Over the last three decades, the chemistry of zirconium has facilitated antibody development and the clinical management of disease in the precision medicine era. Scientists have harnessed its reactivity, coordination chemistry, and nuclear chemistry to develop antibody-based radiopharmaceuticals incorporating zirconium-89 (89Zr: t1/2 = 78.4 h, β+: 22.8%, Eβ+max = 901 keV; EC: 77%, Eγ = 909 keV) to improve disease detection, identify patients for individualized therapeutic interventions. and monitor their response to those interventions. However, release of the 89Zr4+ ion from the radiopharmaceutical remains a concern, since it may confound the interpretation of clinical imaging data, negatively affect dosimetric calculations, and hinder treatment planning. In this report, we relate our novel observations involving the use of polyazamacrocycles as zirconium-89 chelators. We describe the synthesis and complete characterization of zirconium 2,2',2″,2‴-(1,4,7,10-tetraazacyclotridecane-1,4,7,10-tetrayl)tetraacetic acid (Zr-TRITA), zirconium 3,6,9,15-Tetraazabicyclo[9.3.1] pentadeca-1(15),11,13-triene-3,6,9-triacetic acid (Zr-PCTA), and zirconium 2,2',2″-(1,4,7-triazacyclononane-1,4,7-triyl)triacetic acid (Zr-NOTA). In addition, we elucidate the solid-state structure of each complex using single-crystal X-ray diffraction analysis. Finally, we found that [89Zr]Zr-PCTA and [89Zr]Zr-NOTA demonstrate excellent stability in vitro and in vivo and provide a rationale for these observations. These innovative findings have the potential to guide the development of safer and more robust immuno-PET agents to improve precision medicine applications.

Background Topical mometasone is frequently used as an intranasal spray, on drug-eluting stents, and compounded by specialty pharmacies as a sinus rinse. A typical sinus rinse contains 1.2 mg of mometasone dissolved in 240 mL of buffered saline and is flushed through the sinonasal cavity. The mometasone irrigation rapidly flows to the contralateral sinonasal cavity or the nasopharynx with a contact time on the order of 5 to 10 seconds. However, no information is available on the absorption rate of topical mometasone on the sinonasal surface. Methods To determine the absorption characteristics of mometasone, we harvested nasal epithelium from 2 healthy donors and differentiated them into a mature ciliated epithelium on Millicell membranes. We applied mometasone to the apical surface for various time intervals and then rinsed off non-absorbed mometasone with phosphate-buffered saline. Millicell membranes with the adherent epithelial cells were then harvested and stored in guanidine hydrochloride for quantification using high-performance liquid chromatography-mass spectrometry. Results Fifty percent of the maximal absorption occurred after an average of 38 minutes after application, and maximal absorption occurred after an average of 114 minutes. Conclusion Our data provide an estimate for rates of absorption of mometasone applied to the sinonasal cavity and suggest that the absorption rates poorly match contact time during saline lavage.

The cellular environment is dynamic and complex, involving thousands of different macromolecules with total concentrations of hundreds of grams per liter. However, most biochemistry is conducted in dilute buffer where the concentration of macromolecules is less than 10 g/L. High concentrations of macromolecules affect protein stability, function, and protein complex formation, but to understand these phenomena fully we need to know the concentration of the test protein in cells. Here, we quantify the concentration of an overexpressed recombinant protein, a variant of the B1 domain of protein G, in Tuner (DE3)™ Escherichia coli cells as a function of inducer concentration. We find that the protein expression level is controllable, and expression saturates at over 2 m M upon induction with 0.4 m M isopropyl β‐ d ‐thiogalactoside. We discuss the results in terms of what can and cannot be learned from in‐cell protein NMR studies in E. coli .