Umpolung Phosphorylation of Tyrosine via 1,2-Phospha-Brook Rearrangement.

Phosphorylated tyrosine is a fundamental building block of bioactive peptides and proteins. However, the chemoselective phosphorylation of tyrosine over other nucleophilic amino acid residues in unprotected peptides remains a significant challenge. Here we report an umpolung strategy that converts the C-terminal tyrosine into an electrophilic spirolactone cyclohexadienone motif through hypervalent iodine oxidation, followed by a 1,2-phospha-Brook rearrangement using phosphite diesters as nucleophilic phosphoryl donors. This reaction proceeds chemoselectively at the tyrosine phenol and is applicable to a wide range of peptide substrates containing various nucleophilic amino acid residues, including serine and threonine.

Pleomorphic adenoma: Indeed, a versatile tumor.

ABSTRACT: Pleomorphic adenoma is the most common and well-studied salivary gland neoplasm. It is a benign tumor most commonly occurring in the parotid gland although it can be seen in other major and minor salivary glands. There is a variety of metaplasia seen in Pleomorphic adenoma most commonly squamous metaplasia, others noted are osseous metaplasia, oncocytic metaplasia, sebaceous metaplasia, and adipocytic metaplasia. Also, at times tyrosine crystalloids are seen. This study discusses a few of the metaplasia and the presence of tyrosine crystals in pleomorphic adenoma. Indeed, this tumor proves true to its name.

Patterns of intersectional tumor volumes in T2-weighted MRI and [18F]FET PET in adult glioma: a prospective, observational study.

Brain tumor volumes as assessed by magnetic resonance imaging (MRI) do not always spatially overlap with biological tumor volumes (BTV) measured by [18F]Fluoroethyltyrosine positron emission tomography ([18F]FET PET). We prospectively investigated volumetric patterns based on the extent of tumor volume overlap between the two modalities. Eighty-six patients with newly diagnosed glioma who had undergone MRI and [18F]FET PET between 2007 and 2009 were included in this prospective study and (re-)classified according to CNS WHO 2021 (Classification of Tumors of the Central Nervous System by the World Health Organization). Four different patterns of volume overlap were defined mathematically according to the extent of overlap between MRI-based T2 tumor volume (non-enhancing tumor volume, nCEV) and BTVs. Progression-free (PFS) and overall survival (OS) were determined. Seventy patients were diagnosed with isocitrate dehydrogenase wildtype (IDHwt) glioblastoma and 16 with IDH-mutant glioma, respectively. The most common pattern was characterized by a larger non-contrast-enhancing tumor volume (nCEV) that enclosed all or most of the BTV and was observed in 46 patients (54%) (pattern 1). This pattern was more frequent in IDH-mutant gliomas than in IDH-wildtype glioblastoma (81% versus 47%, p = 0.02). In multivariate analyses, pattern 1 was associated with prolonged PFS (HR 0.59; 95 CI 0.34-1.0; p = 0.05), but not OS (HR 0.66; 95 CI 0.4-1.08; p = 0.1). For OS, presence of an IDH mutation (p = 0.05) and lower age (p = 0.03) were associated with prolonged OS. The spatial relation between nCEV and BTV varies within and between glioma entities. Most frequently, a larger nCEV encases the BTV. Some patients show spatially dissociated nCEVs and BTVs. Not accounting for this phenomenon in surgery or radiotherapy planning might lead to undertreatment.

Design, Synthesis and Characterization of Mn(II)Cysteine-Tyrosine Dithiocarbamate Complex for against the Cancer on MCF-7 Breast Cancer Cell Line.

OBJECTIVE: Breast cancer is the most frequently diagnosed cancer and the second cause of death worldwide. The drug often used for chemotherapy is cisplatin. However, the drug cisplatin has a number of problems, including lack of selectivity, undesirable side effects, resistance, and toxicity in the body. So research is carried out on new drug compounds with low toxicity by designing in silico with molecular docking. METHODS: Mn(II) Cysteine-Tyrosine dithiocarbamate is a new complex molecule whose research involves several steps, such as in-silico molecular docking testing with target proteins, ADMET then synthesis, characterization and in-vitro MCF-7 cells for anticancer drugs. The synthesis process involves the reaction of manganese metal with tyrosine, cysteine, CS2 and KOH. Characterization tests have been carried out including FT-IR spectroscopy, SEM-EDS, UV Vis, conductivity, melting point and XRD. RESULT: Confirm the structure of the compound using UV Vis, obtained orbitals π to π* and n to π* in the group N = C = S is represented by the absorption at 400 nm and 600 nm, FT-IR with the results obtained by the functional groups O-H, N-H, C =N and C=S. In vitro test results showed morphological changes (apoptosis) in MCF-7 cancer cells starting from 250 µg/mL and an IC50 value of 416.90 µg/mL. Molecular docking studies of the Mn(II)Cysteine-Tyrosine dithiocarbamate complex were identified with 4,4',4''-[(2R)-butane-1,1,2-triyl]triphenol - Estrogen α which showed an active site with amino acid residues GLU323, GLU385, VAL446, ILE514, TRP360, LYS449, MET388, MET357, PHE445, VAL392 and ILE389. Hydrophobic and hydrophobic bonds are seen in Mn(II)Cysteine-Tyrosine dithiocarbamate - Estrogen α has a bond energy of -77.5372 kJ/mol. CONCLUSION: Despite having a high H-bond interaction intensity, the chemical does not have a powerful enough anticancer impact. Despite the produced compound's low bioactivity, this study should offer important new understandings into how molecular structure affects anticancer activity.

Tyrosine phosphorylation and palmitoylation of TRPV2 ion channel tune microglial beta-amyloid peptide phagocytosis.

Alzheimer's disease (AD) is the leading form of dementia, characterized by the accumulation and aggregation of amyloid in brain. Transient receptor potential vanilloid 2 (TRPV2) is an ion channel involved in diverse physiopathological processes, including microglial phagocytosis. Previous studies suggested that cannabidiol (CBD), an activator of TRPV2, improves microglial amyloid-ß (Aß) phagocytosis by TRPV2 modulation. However, the molecular mechanism of TRPV2 in microglial Aß phagocytosis remains unknown. In this study, we aimed to investigate the involvement of TRPV2 channel in microglial Aß phagocytosis and the underlying mechanisms. Utilizing human datasets, mouse primary neuron and microglia cultures, and AD model mice, to evaluate TRPV2 expression and microglial Aß phagocytosis in both in vivo and in vitro. TRPV2 was expressed in cortex, hippocampus, and microglia.Cannabidiol (CBD) could activate and sensitize TRPV2 channel. Short-term CBD (1 week) injection intraperitoneally (i.p.) reduced the expression of neuroinflammation and microglial phagocytic receptors, but long-term CBD (3 week) administration (i.p.) induced neuroinflammation and suppressed the expression of microglial phagocytic receptors in APP/PS1 mice. Furthermore, the hyper-sensitivity of TRPV2 channel was mediated by tyrosine phosphorylation at the molecular sites Tyr(338), Tyr(466), and Tyr(520) by protein tyrosine kinase JAK1, and these sites mutation reduced the microglial Aß phagocytosis partially dependence on its localization. While TRPV2 was palmitoylated at Cys 277 site and blocking TRPV2 palmitoylation improved microglial Aß phagocytosis. Moreover, it was demonstrated that TRPV2 palmitoylation was dynamically regulated by ZDHHC21. Overall, our findings elucidated the intricate interplay between TRPV2 channel regulated by tyrosine phosphorylation/dephosphorylation and cysteine palmitoylation/depalmitoylation, which had divergent effects on microglial Aß phagocytosis. These findings provide valuable insights into the underlying mechanisms linking microglial phagocytosis and TRPV2 sensitivity, and offer potential therapeutic strategies for managing AD.

Biomolecular Dynamics of Nitric Oxide Metabolites and HIF1α in HPV Infection.

INTRODUCTION: Viral infections cause oxygen deprivation, leading to hypoxia or anoxia in certain tissues. The limitation of mitochondrial respiration is one of the major events during hypoxia that induces alternative metabolic activities and increased levels of certain biomolecules such as nitric oxide (NO) metabolites. In this study, we aimed to investigate the role of NO metabolites and hypoxia in HPV infection. MATERIALS AND METHODS: We included 36 patients with palmoplantar warts and 36 healthy subjects and performed serum determinations of NO metabolites (direct nitrite, total nitrite, nitrate, and 3-nitrotyrosine) and HIF1α, a marker of hypoxia. RESULTS: We found elevated serum levels in NO metabolites and HIF1α, and decreased direct nitrite/nitrate ratios in patients with warts versus controls. Additionally, we identified statistically significant positive correlations between NO metabolites and HIF1α levels, except for 3-nitrotyrosine. CONCLUSIONS: Our findings show that HPV infection causes hypoxia and alterations in NO metabolism and suggest a link between wart development and cellular stress. Our research could provide new insights for a comprehensive understanding of the pathogenesis of cutaneous HPV infections.

An LC-MS/MS method for the quantification of 3-bromotyrosine in plasma from patients diagnosed with eosinophilic esophagitis.

Eosinophilic esophagitis (EoE) is a disease marked by a surplus of eosinophils, a type of white blood cell that causes inflammation and irritation. The current diagnostic and monitoring procedure for EoE is endoscopy with biopsy, which is invasive, expensive, and leads to tissue tearing in patients. A biomarker in plasma would offer a much less invasive form of disease monitoring for patients with EoE. Eosinophils have been shown to make eosinophil peroxidase, an enzyme that produces hypobromous acid, reacts with primary amines, and forms bromoamides. One product of this biochemical reaction is 3-bromotyrosine. We have optimized a selective, sensitive, and reproducible method to detect and quantify L-tyrosine and 3-bromotyrosine in human plasma using high-pressure liquid chromatography and tandem mass spectrometry (HPLC-MS/MS). Our sample preparation and analysis method requires fewer steps and provides a faster analysis than previous methods. Method validation yielded limits of quantification of 50 ng mL-1 for L-tyrosine and 10 ng mL-1 for 3-bromotyrosine. Calibration curves for quantification were linear from 50 to 500 ng mL-1 with an R2 value of 0.9995 for L-tyrosine and 10 to 300 ng mL-1 with an R2 value of 0.9998 for 3-bromotyrosine. Method variability was assessed resulting in relative standard deviations of 0.98-4.6% for 3-bromotyrosine (n = 18) and 0.20-0.58% for L-tyrosine (n = 18). Method applicability was tested with patients with a confirmed diagnosis of EoE, initially suggesting little to no correlation between eosinophil count and 3-bromotyrosine concentration in plasma. However, we do observe a relationship between eosinophil count and esophageal deformities. More research must be conducted to determine a more definitive correlation.

Ultraviolet irradiation enhances the nitration of allergens.

Ultraviolet (UV) light is widely used for disinfection in indoor environments. Some wavelengths of UV light can produce high concentration of O3. UV irradiation combined with O3 may have great potential for nitration of allergens in the presence of NO2 in the air. In this study, the effects of UV irradiation on the nitration of three major indoor allergens including group Ⅰ allergens of house dust mite (Der p 1 and Der f 1) and group Ⅰ allergen of dog (Can f 1) in the presence of NO2 and O3 were investigated by analysis of the protein quantity, tyrosine, peptides, and nitration degree. The results showed that UV irradiation induced a significant increase in the quantity of 3-nitrotyrosine in the allergens from 0.4 ± 0.4 ng to 4.0 ± 0.8 ng. After 12 h of UV-O3 co-exposure, the total nitration degrees of the three allergens ranged from 0.1% to 0.5%, which were significantly higher than those after only O3 exposure (p < 0.05). The analysis of peptides revealed that the nitration of tyrosine was site-specific. The tyrosine Y231, which was adjacent to aspartic acid, posed the highest nitration degree of 41.1 ± 24.0% in Der p 1. The nitration degree of tyrosine Y162 was the highest (1.7 ± 0.1%) in Der f 1. Overall, this study demonstrated that UV irradiation enhanced the O3-related nitration of allergens in the air, which provides an experimental basis for the impact of daily disinfection behavior on allergens.

Chronic Activation of Tubulin Tyrosination Improves Heart Function.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is the most common cardiac genetic disorder caused by sarcomeric gene variants and associated with left ventricular hypertrophy and diastolic dysfunction. The role of the microtubule network has recently gained interest with the findings that microtubule detyrosination (dTyr-MT) is markedly elevated in heart failure. Acute reduction of dTyr-MT by inhibition of the detyrosinase (VASH [vasohibin]/SVBP [small VASH-binding protein] complex) or activation of the tyrosinase (TTL [tubulin tyrosine ligase]) markedly improved contractility and reduced stiffness in human failing cardiomyocytes and thus posed a new perspective for HCM treatment. In this study, we tested the impact of chronic tubulin tyrosination in an HCM mouse model (Mybpc3 knock-in), in human HCM cardiomyocytes, and in SVBP-deficient human engineered heart tissues (EHTs). METHODS: Adeno-associated virus serotype 9-mediated TTL transfer was applied in neonatal wild-type rodents, in 3-week-old knock-in mice, and in HCM human induced pluripotent stem cell-derived cardiomyocytes. RESULTS: We show (1) TTL for 6 weeks dose dependently reduced dTyr-MT and improved contractility without affecting cytosolic calcium transients in wild-type cardiomyocytes; (2) TTL for 12 weeks reduced the abundance of dTyr-MT in the myocardium, improved diastolic filling, compliance, cardiac output, and stroke volume in knock-in mice; (3) TTL for 10 days normalized cell area in HCM human induced pluripotent stem cell-derived cardiomyocytes; (4) TTL overexpression activated transcription of tubulins and other cytoskeleton components but did not significantly impact the proteome in knock-in mice; (5) SVBP-deficient EHTs exhibited reduced dTyr-MT levels, higher force, and faster relaxation than TTL-deficient and wild-type EHTs. RNA sequencing and mass spectrometry analysis revealed distinct enrichment of cardiomyocyte components and pathways in SVBP-deficient versus TTL-deficient EHTs. CONCLUSIONS: This study provides the first proof of concept that chronic activation of tubulin tyrosination in HCM mice and in human EHTs improves heart function and holds promise for targeting the nonsarcomeric cytoskeleton in heart disease.

Low-Dose Radiation Induces Alterations in Fatty Acid and Tyrosine Metabolism in the Mouse Hippocampus: Insights from Integrated Multiomics.

In recent years, there has been a drastic surge in neurological disorders with sporadic cases contributing more than ever to their cause. Radiation exposure through diagnostic or therapeutic routes often results in neurological injuries that may lead to neurodegenerative pathogenesis. However, the underlying mechanisms regulating the neurological impact of exposure to near-low doses of ionizing radiation are not known. In particular, the neurological changes caused by metabolomic reprogramming have not yet been elucidated. Hence, in the present study, C57BL/6 mice were exposed to a single whole-body X-ray dose of 0.5 Gy, and 14 days post-treatment, the hippocampus was subjected to metabolomic analysis. The hippocampus of the irradiated animals showed significant alterations in 15 metabolites, which aligned with altered tyrosine, phenylalanine, and alpha-linolenic acid metabolism and the biosynthesis of unsaturated fatty acids. Furthermore, a multiomics interaction network comprising metabolomics and RNA sequencing data analysis provided insights into gene-metabolite interactions. Tyrosine metabolism was revealed to be the most altered, which was demonstrated by the interaction of several crucial genes and metabolites. The present study revealed the regulation of low-dose radiation-induced neurotoxicity at the metabolomic level and its implications for the pathogenesis of neurological disorders. The present study also provides novel insights into metabolomic pathways altered following near-low-dose IR exposure and its link with neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease.

Step-by-step optimization of a heterologous pathway for de novo naringenin production in Escherichia coli.

Naringenin is a plant polyphenol, widely explored due to its interesting biological activities, namely anticancer, antioxidant, and anti-inflammatory. Due to its potential applications and attempt to overcome the industrial demand, there has been an increased interest in its heterologous production. The microbial biosynthetic pathway to produce naringenin is composed of tyrosine ammonia-lyase (TAL), 4-coumarate-CoA ligase (4CL), chalcone synthase (CHS), and chalcone isomerase (CHI). Herein, we targeted the efficient de novo production of naringenin in Escherichia coli by performing a step-by-step validation and optimization of the pathway. For that purpose, we first started by expressing two TAL genes from different sources in three different E. coli strains. The highest p-coumaric acid production (2.54 g/L) was obtained in the tyrosine-overproducing M-PAR-121 strain carrying TAL from Flavobacterium johnsoniae (FjTAL). Afterwards, this platform strain was used to express different combinations of 4CL and CHS genes from different sources. The highest naringenin chalcone production (560.2 mg/L) was achieved by expressing FjTAL combined with 4CL from Arabidopsis thaliana (At4CL) and CHS from Cucurbita maxima (CmCHS). Finally, different CHIs were tested and validated, and 765.9 mg/L of naringenin was produced by expressing CHI from Medicago sativa (MsCHI) combined with the other previously chosen genes. To our knowledge, this titer corresponds to the highest de novo production of naringenin reported so far in E. coli. KEY POINTS: • Best enzyme and strain combination were selected for de novo naringenin production. • After genetic and operational optimizations, 765.9 mg/L of naringenin was produced. • This de novo production is the highest reported so far in E. coli.

In vivo dissection of the mouse tyrosine catabolic pathway with CRISPR-Cas9 identifies modifier genes affecting hereditary tyrosinemia type 1.

Hereditary tyrosinemia type 1 is an autosomal recessive disorder caused by mutations (pathogenic variants) in fumarylacetoacetate hydrolase, an enzyme involved in tyrosine degradation. Its loss results in the accumulation of toxic metabolites that mainly affect the liver and kidneys and can lead to severe liver disease and liver cancer. Tyrosinemia type 1 has a global prevalence of approximately 1 in 100,000 births but can reach up to 1 in 1,500 births in some regions of Québec, Canada. Mutating functionally related "modifier' genes (i.e. genes that, when mutated, affect the phenotypic impacts of mutations in other genes) is an emerging strategy for treating human genetic diseases. In vivo somatic genome editing in animal models of these diseases is a powerful means to identify modifier genes and fuel treatment development. In this study, we demonstrate that mutating additional enzymes in the tyrosine catabolic pathway through liver-specific genome editing can relieve or worsen the phenotypic severity of a murine model of tyrosinemia type 1. Neonatal gene delivery using recombinant adeno-associated viral vectors expressing Staphylococcus aureus Cas9 under the control of a liver-specific promoter led to efficient gene disruption and metabolic rewiring of the pathway, with systemic effects that were distinct from the phenotypes observed in whole-body knockout models. Our work illustrates the value of using in vivo genome editing in model organisms to study the direct effects of combining pathological mutations with modifier gene mutations in isogenic settings.

Intersite communication in dimeric enzymes highlighted by structural and thermodynamic analysis of didansyltyrosine binding to thymidylate synthases.

Intersite communication in dimeric enzymes, triggered by ligand binding, represents both a challenge and an opportunity in enzyme inhibition strategy. Though often understestimated, it can impact on the in vivo biological mechansim of an inhibitor and on its pharmacokinetics. Thymidylate synthase (TS) is a homodimeric enzyme present in almost all living organisms that plays a crucial role in DNA synthesis and cell replication. While its inhibition is a valid strategy in the therapy of several human cancers, designing specific inhibitors of bacterial TSs poses a challenge to the development of new anti-infective agents. N,O-didansyl-l-tyrosine (DDT) inhibits both Escherichia coli TS (EcTS) and Lactobacillus casei TS (LcTS). The available X-ray structure of the DDT:dUMP:EcTS ternary complex indicated an unexpected binding mode for DDT to EcTS, involving a rearrangement of the protein and addressing the matter of communication between the two active sites of an enzyme dimer. Combining molecular-level information on DDT binding to EcTS and LcTS extracted from structural and FRET-based fluorometric evidence with a thermodynamic characterization of these events obtained by fluorometric and calorimetric titrations, this study unveiled a negative cooperativity between the DDT bindings to the two monomers of each enzyme dimer. This result, complemented by the species-specific thermodynamic signatures of the binding events, implied that communication across the protein dimer was triggered by the first DDT binding. These findings could challenge the conventional understanding of TS inhibition and open the way for the development of novel TS inhibitors with a different mechanism of action and enhanced efficacy and specificity.

Tyrosine and tryptophan in urine as biomarkers for prostate cancer: A validation study.

Prostate cancer (PCa) is a common male malignancy and early diagnosis is crucial for successful treatment. The current study aims to validate results from a pilot study that demonstrated an inverse association between urine tyrosine and tryptophan levels and the severity of PCa. This study comprised a cohort of 97 patients with benign prostatic hyperplasia, 93 patients diagnosed with localized PCa, 75 patients diagnosed with locally advanced PCa, and 68 patients diagnosed with metastatic PCa. The tyrosine and tryptophan levels in the samples were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and electrochemical sensors in accordance with the pilot to maintain uniformity for accurately evaluating the data. One-way ANOVA with post Tukey test as well as the Wilcoxon Rank Sum Test were performed. Analyzing 333 patients across PCa stages with consistent methods, we observed no significant differences in tyrosine and tryptophan levels between PCa patients and controls, finally rejecting the use of tyrosine and tryptophan as PCa biomarkers. We did, however, verify the strong correlation between the urinary concentrations of tyrosine and tryptophan found in the pilot study.

Tyrosine-Like Crystalloids Localize to Non-Neoplastic True Vocal Cord and Attachments.

BACKGROUND: Tyrosine-rich or tyrosine-like crystalloids (TC) were initially described in salivary gland pleomorphic adenoma. The presence of TC in non-neoplastic tissues is rare, and it has been reported exclusively in the larynx. This study aims to characterize the frequency and anatomical localization of TC in total laryngectomy specimens. METHODS: Review of consecutive laryngectomy specimens in which the cassette summary documented parasagittal section sampling of the right and left vocal folds and the anterior commissure. Data collected included patient demographics, underlying diagnoses, history of radiation therapy, presence, and location of TC. RESULTS: Of 86 laryngectomy specimens, 16 (19%) contained amphophilic to eosinophilic TC. The study cohort included 11 males and 5 females, aged 37 to 85 years (mean 62, median 63). Laryngectomy surgery was performed for advanced untreated squamous cell carcinoma (SCCa) (7/16, 43.75%), recurrent post-treatment SCCa (7/16, 43.75%), previously untreated laryngeal large cell neuroendocrine carcinoma (1/16, 6.25%), and non-functional larynx post-chemoradiation (1/16, 6.25%). According to the macroscopic cassette summary, TC were predominantly found in the anterior commissure Sect. (13/16, 81.25%), with fewer cases in sections containing the left (2/16, 12.5%) or the right (1/16, 6.25%) vocal folds. Microscopically, TC localized to the anterior macula flava and/or adjacent vocal ligament (12/16, 75%) and the anterior commissure tendon (4/16, 25%). CONCLUSIONS: TCs are predominantly reported as admixed with a neoplasm, however this study confirms that TC can also occur in non-neoplastic tissues of the larynx. There was no clear relationship between the presence of TC and prior radiation therapy. TC in the specialized connective tissues of the macula flava and true cord tendinous insertions distinct from tumor may form in response to alterations in mechanical stress, though an age-related change within the spectrum of normal laryngeal microanatomy also remains a possibility.

Ethylene oxide suppresses boar sperm function during capacitation.

Ethylene oxide (E.O) is an epoxide compound, and it has been utilized as a sterilizer or production of ether compounds in several industries. Although the toxic effects of E.O on bacteria and mammals have been reported, its effects on male reproductive toxicity during sperm capacitation are not fully understood. Therefore, this study was designed to evaluate the effects of E.O exposure during sperm capacitation. Boar spermatozoa were treated with various E.O concentrations (0, 0.1, 1, 10, and 100 µÐœ). After exposure, sperm motility, motion kinematics, capacitation status, intracellular ATP levels, cell viability, expression levels of protein kinase A (PKA) activation, and tyrosine phosphorylation were evaluated. Results revealed that E.O exposure significantly decreased sperm motility, motion kinematics, and intracellular ATP levels but significantly increased the capacitated spermatozoa. In addition, the PKA activation and tyrosine phosphorylation were abnormally changed. According to our results, E.O may cause toxic effects on sperm function during capacitation, which induces male reproductive toxicity. Consequently, we suggest that male reproductive toxicity should be considered when using E.O.

Development and validation of a HPLC method for the determination of chemical and radiochemical purity of O-(2-[18F]fluoroethyl-l-tyrosine ([18F]FET)), a PET radiotracer for the imaging of brain tumor.

A novel HPLC method was developed and validated to determine radiochemical identity, radiochemical purity and chemical purity for the analysis of O-(2-[18F]fluoroethyl-l-tyrosine ([18F]FET). In this method, an analytical Phenomenex Gemini C18 column was used with an isocratic eluent of 7 % ethanol and 93 % 50 mM potassium phosphate buffer (pH = 6.9). The flow rate was 1.0 mL/min and the injection volume was 10 µL. A photo-diode array detector set at 220 nm was used for UV mass detection and a single channel, high sensitivity radiation detector was used. The method validation assays including specificity, linearity, precision, accuracy, and robustness were evaluated. Results show that the method was suitable for qualitative and quantitative determination of radiochemical and chemical purity of [18F]FET. This system has been routinely used for the analysis of more than 120 batches of [18F]FET with radiochemical yield 23.7 ± 6 % (no decay corrected) and molar activity 593 ± 284 GBq/µmole in our facility to support human use.

Are Carriers Unaffected? A Literature Review of Metabolic and Health Outcomes among Genetic Carriers of Phenylketonuria.

BACKGROUND: Phenylketonuria (PKU) is an autosomal recessive genetic condition that results in reduced enzymatic functioning within the phenylalanine hydroxylase (PAH) pathway, which is involved in the metabolism of phenylalanine (Phe) into tyrosine (Tyr). Without dietary intervention, individuals with PKU exhibit significantly elevated levels of Phe, which is presumed to cause severe neurological dysfunction and other associated health risks. Carriers of PKU are heterozygotes for a PAH gene mutation and are typically described in the literature as "unaffected." However, decades of existing research challenges this classical thinking and it is plausible that these individuals currently classified as carriers may present with an intermediate phenotype or may be "moderately affected." SUMMARY: The purpose of this scoping review was to explore this hypothesis further, by searching for and summarizing existing literature on metabolism and health outcomes among PKU carriers. Preliminary research has suggested that some PKU carriers exhibit reduced PAH enzyme function, and relatedly, elevated circulating Phe levels compared to noncarriers. In addition, Phe dosing trials have further demonstrated that carriers have increased Phe levels and decreased Tyr levels compared to noncarriers. Because of these metabolic perturbations, it is biologically plausible for carriers to experience an intermediate phenotype in terms of metabolic consequences and clinical outcomes. While these outcomes have yet to be thoroughly explored, early research has found associations between PKU carrier status and lower IQs as well as decreased executive functioning, memory, processing speed, and inhibitory control. The PAH pathway is also involved in melanogenesis, and research has demonstrated increased melanoma risk among PKU carriers. However, there are many limitations to this research, and thus whether or not carriers are clinically impacted cannot yet be conclusively determined. KEY MESSAGE: Overall, while preliminary research suggests a possible intermediate phenotype among PKU carriers, the current available research is limited and PKU carriers are still clinically considered "unaffected." This review outlines the current literature while discussing future research endeavors related to the metabolism and health of PKU carriers.

The role of tissue persistent organic pollutants and genetic polymorphisms in patients with benign and malignant kidney tumors.

This study aimed to explore whether there is an association between environmental exposure to POPs and kidney tumor induction, and whether blood POP concentrations reflect kidney tissue concentrations. POP derivatives were determined in blood, tumor tissue, tumor surrounding tissue, and perirenal fat tissue samples taken from patients who underwent surgery for renal tumors. A voluntary control group was recruited for blood and urine samples as well. Urinary excretions of o,o'-dityrosine, chlorotyrosine, nitrotyrosine, and 8-OHdG were measured in the same patients. The possible role of genetic polymorphisms in CYP1A1, GST isozymes P, M, and T, and hOGG1 genes on the predisposition to renal cancer was investigated. Some POPs have been found to be associated with kidney cancer, as evidenced by their significantly high ORs. 8-OHdG levels were significantly higher compared to the control group. The GSTT1 null polymorphism can be a risk factor for malignant but not for benign kidney tumors.

Probing the Electrostatic Effects of H-Ras Tyrosine 32 Mutations on Intrinsic GTP Hydrolysis Using Vibrational Stark Effect Spectroscopy of a Thiocyanate Probe.

The wildtype H-Ras protein functions as a molecular switch in a variety of cell signaling pathways, and mutations to key residues result in a constitutively active oncoprotein. However, there is some debate regarding the mechanism of the intrinsic GTPase activity of H-Ras. It has been hypothesized that ordered water molecules are coordinated at the active site by Q61, a highly transforming amino acid site, and Y32, a position that has not previously been investigated. Here, we examine the electrostatic contribution of the Y32 position to GTP hydrolysis by comparing the rate of GTP hydrolysis of Y32X mutants to the vibrational energy shift of each mutation measured by a nearby thiocyanate vibrational probe to estimate changes in the electrostatic environment caused by changes at the Y32 position. We further compared vibrational energy shifts for each mutation to the hydration potential of the respective side chain and demonstrated that Y32 is less critical for recruiting water molecules into the active site to promote hydrolysis than Q61. Our results show a clear interplay between a steric contribution from Y32 and an electrostatic contribution from Q61 that are both critical for intrinsic GTP hydrolysis.