Intensive determination of storage condition effects on human plasma metabolomics

Introduction

Human plasma metabolomics offer powerful tools for understanding disease mechanisms and identifying clinical biomarkers for diagnosis, efficacy prediction and patient stratification. Although storage conditions can affect the reliability of data from metabolites, strict control of these conditions remains challenging, particularly when clinical samples are included from multiple centers. Therefore, it is necessary to consider stability profiles of each analyte.

Objectives

The purpose of this study was to extract unstable metabolites from vast metabolome data and identify factors that cause instability.

Method

Plasma samples were obtained from five healthy volunteers, were stored under ten different conditions of time and temperature and were quantified using leading-edge metabolomics. Instability was evaluated by comparing quantitation values under each storage condition with those obtained after ?80 °C storage.

Result

Stability profiling of the 992 metabolites showed time- and temperature-dependent increases in numbers of significantly changed metabolites. This large volume of data enabled comparisons of unstable metabolites with their related molecules and allowed identification of causative factors, including compound-specific enzymatic activity in plasma and chemical reactivity. Furthermore, these analyses indicated extreme instability of 1-docosahexaenoylglycerol, 1-arachidonoylglycerophosphate, cystine, cysteine and N⁶-methyladenosine.

Conclusion

A large volume of data regarding storage stability was obtained. These data are a contribution to the discovery of biomarker candidates without misselection based on unreliable values and to the establishment of suitable handling procedures for targeted biomarker quantification.

     

Cone-Beam Computed Tomography Correlates with Conventional Helical Computed Tomography in Evaluation of Lipiodol Accumulation in HCC after Chemoembolization

Background & Aims

The amount of drug-loaded lipiodol in an HCC tumor post-transarterial chemoembolization (TACE) correlates with the risk of local tumor recurrence. Lipiodol enhancement of a tumor on conventional CT, measured in Hounsfield units (HU), can predict tumor response. Here we investigate whether cone-beam CT (CBCT) can also be used to predict tumor response, providing the benefit of being able to optimize the patient’s treatment plan intra-procedurally.

Methods

A total of 82 HCC nodules (82 patients), ≤5 cm in diameter, were treated with balloon-occluded TACE using miriplatin between December 2013 and November 2014. For each patient, both CBCT and conventional CT images were obtained post-TACE. The degree of correlation between CBCT and conventional CT was determined by comparing identical regions of interest for each imaging modality using pixel values.

Results

The pixel values from conventional CT and CBCT were highly correlated, with a Pearson correlation coefficient of 0.912 (p<0.001). The location of the nodules within the liver did not affect the results; the correlation coefficient was 0.891 (p<0.001) for the left lobe and 0.926 (p<0.001) for the right lobe. The mean pixel value for conventional CT was 439 ± 279 HU, and the mean pixel value for CBCT was 416 ± 311 HU.

Conclusions

CBCT may be used as a substitute for conventional CT to quantitatively evaluate the amount of drug-loaded lipiodol within an HCC nodule and, hence, the efficacy of TACE treatment. The major benefit of using CBCT is the ability to predict the likelihood of local recurrence intra-procedurally, enabling subsequent treatment optimization.     

Mtu1-Mediated Thiouridine Formation of Mitochondrial tRNAs Is Required for Mitochondrial Translation and Is Involved in Reversible Infantile Liver Injury

Reversible infantile liver failure (RILF) is a unique heritable liver disease characterized by acute liver failure followed by spontaneous recovery at an early stage of life. Genetic mutations in MTU1 have been identified in RILF patients. MTU1 is a mitochondrial enzyme that catalyzes the 2-thiolation of 5-taurinomethyl-2-thiouridine (τm⁵s²U) found in the anticodon of a subset of mitochondrial tRNAs (mt-tRNAs). Although the genetic basis of RILF is clear, the molecular mechanism that drives the pathogenesis remains elusive. We here generated liver-specific knockout of Mtu1 (Mtu1^LKO) mice, which exhibited symptoms of liver injury characterized by hepatic inflammation and elevated levels of plasma lactate and AST. Mechanistically, Mtu1 deficiency resulted in a loss of 2-thiolation in mt-tRNAs, which led to a marked impairment of mitochondrial translation. Consequently, Mtu1^LKO mice exhibited severe disruption of mitochondrial membrane integrity and a broad decrease in respiratory complex activities in the hepatocytes. Interestingly, mitochondrial dysfunction induced signaling pathways related to mitochondrial proliferation and the suppression of oxidative stress. The present study demonstrates that Mtu1-dependent 2-thiolation of mt-tRNA is indispensable for mitochondrial translation and that Mtu1 deficiency is a primary cause of RILF. In addition, Mtu1 deficiency is associated with multiple cytoprotective pathways that might prevent catastrophic liver failure and assist in the recovery from liver injury.     

Month of birth is associated with mortality among older people in Japan: Findings from the JAGES cohort

Month of birth (MOB) has been linked to a variety of health conditions in adulthood. This study examined the association between MOB and mortality among the healthy elderly in Japan, where a practice of traditional age reckoning was employed up until the late 1940s. The results showed male participants born in December were more likely to die earlier while those born in January had lower mortality. It is possible that social factors in early life, such as the time period when a birth is officially registered, may have implications for health that stretch across the life course.     

Comparison of patient-specific intensity modulated radiation therapy quality assurance for the prostate across multiple institutions

AimTo evaluate the success of a patient-specific intensity modulated radiation therapy (IMRT) quality assurance (QA) practice for prostate cancer patients across multiple institutions using a questionnaire survey.BackgroundThe IMRT QA practice involves different methods of dose distribution verification and analysis at different institutions.Materials and MethodsTwo full-arc volumetric modulated arc therapy (VMAT) plan and 7 fixed-gantry IMRT plan with DMLC were used for patient specific QA across 22 institutions. The same computed tomography image and structure set were used for all plans. Each institution recalculated the dose distribution with fixed monitor units and without any modification. Single-point dose measurement with a cylindrical ionization chamber and dose distribution verification with a multi-detector or radiochromic film were performed, according to the QA process at each institution.ResultsTwenty-two institutions performed the patient-specific IMRT QA verifications. With a single-point dose measurement at the isocenter, the average difference between the calculated and measured doses was 0.5 ± 1.9%. For the comparison of dose distributions, 18 institutions used a two or three-dimensional array detector, while the others used Gafchromic film. In the γ test with dose difference/distance-to-agreement criteria of 3%?3 mm and 2%?2 mm with a 30% dose threshold, the median gamma pass rates were 99.3% (range: 41.7%–100.0%) and 96.4% (range: 29.4%–100.0%), respectively.ConclusionThis survey was an informative trial to understand the verification status of patient-specific IMRT QA measurements for prostate cancer. In most institutions, the point dose measurement and dose distribution differences met the desired criteria.     

Optimization of 5,6,7,8-tetrahydropyrido[4,3-d]pyrimidines to generate a highly selective PI3Kδ inhibitor

Chemical optimization of the 5,6,7,8-tetrahydropyrido[4,3-d]pyrimidine (THPP) scaffold was conducted with a focus on cellular potency while maintaining high selectivity against PI3K isoforms. Compound 11f was identified as a potent, highly selective and orally available PI3Kδ inhibitor. In addition, 11f exhibited efficacy in an in vivo antibody production model. The desirable drug-like properties and in vivo efficacy of 11f suggest its potential as a drug candidate for the treatment of autoimmune diseases and leukocyte malignancies.     

Spatial heterogeneity in induced defense of Brachionus calyciflorus within a single lake caused by a bed of floating-leaved macrophyte Trapa species

Limnology - While induced defense of aquatic organisms against predators has been considerably studied by both laboratory and field research, our understanding is still limited about, for example,...     

Analysis of terminal sugar moieties and species-specificities of acrosome reaction-inducing substance in Xenopus (ARISX)

The acrosome reaction of Xenopus sperm is triggered by the acrosome reaction-inducing substance in Xenopus (ARISX), an oviductal pars recta-derived, sugar-rich substance decorated on the entire surface of the vitelline envelope (VE) during ovulation. Here we addressed the functional importance of the sugar moiety in ARISX. Among various lectins examined, soybean agglutinin and Dolichos biflorus agglutinin were shown to abolish the acrosome reaction-inducing activity of ARISX present in pars recta extract or on the VE, indicating the importance of the terminal alpha-N-acetylgalactosamine residue for the function of ARISX. Consistently, the acrosome reaction-inducing activity was not affected by proteinase K digestion, in spite of the simultaneous shift of ARISX to a smaller molecular weight. Indirect immunofluorescence microscopic examinations showed that ARISX was distributed as two types of structures on VE; thick fiber-like materials and thin filamentous materials, and that a new structure appeared on the fertilization envelope instead of the thin filamentous materials. Sperm from several amphibian species were subjected to an in vitro assay during induction of the acrosome reaction with ARISX. The resulting limited population of sperm from a non-Xenopus species underwent acrosome reaction, implying a weak species-specificity of ARISX.