[Storage Stability of Nitrite in Nitrite Analysis of Meat Products]

For the analysis of nitrite ions in food, the stabilities of nitrite ions in meat products and their standard solutions were evaluated. Nitrite is easily oxidized or reduced; hence, products with standard solutions or colour retention agent must be carefully handled. To assess the stability and decreasing trend of nitrite, we examined the storage stability of standard solutions using calibration curves, the time course of nitrite in chopped meat products stored under different conditions, and the time course of nitrite in the sample solutions. Regarding calibration curves, the storage stability was determined for standard solutions that were prepared with ultrapure water at concentrations of 0.025 and 0.4 μg/mL and were stored at 5℃ for one year. The results revealed no changes in concentration of any solution over time, suggesting that no readjustments to the standard solution concentration were necessary before testing until one year after their preparation. Time course of nitrite in chopped meat products stored under different conditions showed a significant decrease in nitrite in refrigerated storage (5℃), whereas stability of nitrite was maintained for up to 1 day in frozen storage (-20℃) and for 14 days in frozen storage (-40℃). The time course of nitrite in the sample solutions showed that the quantitative values of nitrite in the extract remained unchanged within one week of extraction for the meat products tested in the study.

Larger Posterior Revascularization Associated with Reduction of Choroidal Anastomosis in Moyamoya Disease: A Quantitative Angiographic Analysis

BACKGROUND AND PURPOSE

Choroidal anastomosis, a hemorrhage-prone periventricular collateral manifestation in Moyamoya disease, outflows to the cortex posterior to the central sulcus. The objective of the present study was to test whether the angiographic extent of revascularization posterior to the central sulcus contributes to the postoperative reduction of choroidal anastomosis.

MATERIALS AND METHODS

This retrospective cohort study included choroidal anastomosis-positive hemispheres before direct bypass surgery. The postoperative reduction of choroidal anastomosis was determined by a consensus of 2 raters according to the previous research. An imaging software automatically traced the angiographic revascularization area, which was subsequently divided into anterior and posterior parts by an anatomic line corresponding to the central sulcus. Each area was quantitatively measured as a percentage relative to the whole supratentorial area.

RESULTS

Postoperative reduction of choroidal anastomosis was achieved in 68 (85.0%) of the 80 included hemispheres. The revascularization area posterior to the central sulcus was significantly larger in the hemispheres with reduction than in those with no reduction (mean, 15.2% [SD, 7.1%] versus 4.2% [SD, 3.4%], P < .001), whereas no significant difference was observed in the revascularization area anterior to the central sulcus. Multivariate analysis revealed that the revascularization area posterior to the central sulcus was the only significant factor associated with reduction (OR, 1.57; 95% CI, 1.21-2.03, for every 1% increase).

CONCLUSIONS

The results suggest that a larger revascularization posterior to the central sulcus is associated with postoperative reduction of choroidal anastomosis regardless of the extent of anterior revascularization. It might facilitate optimal selection of the revascularization site for preventing hemorrhage.

Genetic and Functional Analyses of Archaeal ATP-Dependent RNA Ligase in C/D Box sRNA Circularization and Ribosomal RNA Processing

RNA ligases play important roles in repairing and circularizing RNAs post-transcriptionally. In this study, we generated an allelic knockout of ATP-dependent RNA ligase (Rnl) in the hyperthermophilic archaeon Thermococcus kodakarensis to identify its biological targets. A comparative analysis of circular RNA reveals that the Rnl-knockout strain represses circularization of C/D box sRNAs without affecting the circularization of tRNA and rRNA processing intermediates. Recombinant archaeal Rnl could circularize C/D box sRNAs with a mutation in the conserved C/D box sequence element but not when the terminal stem structures were disrupted, suggesting that proximity of the two ends could be critical for intramolecular ligation. Furthermore, T. kodakarensis accumulates aberrant RNA fragments derived from ribosomal RNA in the absence of Rnl. These results suggest that Rnl is responsible for C/D box sRNA circularization and may also play a role in ribosomal RNA processing.

[Study of Rapid HPLC Method for the Determination of Antioxidants in Foods, and Standard Solution Stability during Storage]

In this study, we simultaneously determined three antioxidants, butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), and tert-butylhydroquinone (TBHQ), using HPLC equipped both with a photodiode array detector and a fluorescence detector in 25 minutes per sample. Due to the combined use of the two detectors, we could achieve improved target selectivity. Further, quantification at the specific wavelengths for each target substance particularly increased BHT detection sensitivity. This approach enabled us to avoid repeated measurements during daily inspections. Furthermore, detections were performed using LC-MS/MS instead of GC-MS to overcome the problem of helium gas shortage.In addition, we investigated antioxidant stability in standard solutions during storage. Although TBHQ was stable in methanol with ascorbic acid at -20℃, ascorbic acid storage has possibility to lead to decrease in BHT and BHA concentrations. We recognized that the mixture of BHT and BHA dissolved in methanol at 4℃ and that of BHT, BHA and TBHQ dissolved in methanol with ascorbic acid at -20℃ were suitable for about one year.

POS0718 CLINICAL CHARACTERISTICS ASSOCIATED WITH GLANDULAR INVOLVEMENT EVALUATED BY SALIVARY GLAND ULTRASONOGRAPHY IN SJÖGREN’S SYNDROME

Background:

Sjögren’s syndrome (SS) is a systemic autoimmune disease characterized by periductal lymphocytic infiltration of the salivary and lacrimal glands, which results in reduced secretory functions and oral and ocular dryness (1). In addition, patients often have extraglandular manifestations, such as interstitial pneumonia and interstitial nephritis, and the appearance of autoantibodies such as anti-Ro/SS-A and La/SS-B antibodies. Salivary gland ultrasonography (SGUS) is typically used to evaluate the findings of salivary glands; thus, we can evaluate the severity of salivary gland disorders due to SS using SGUS in real time (2).

Objectives:

To identify clinical indices, including disease activity, associated with glandular involvement evaluated using SGUS in patients with SS.

Methods:

We enrolled patients with SS (n=115) and non-SS sicca subjects (n=90) who visited Nagasaki University Hospital between 1995 and 2019. The patients’ SS classifications were based on the 2002 American–European Consensus Group (AECG) SS classification criteria (3). The non-SS sicca subjects exhibited sicca symptoms but did not fulfill the AECG SS classification criteria. SGUS and clinical indices such as age, sex, the focus score (FS), sicca symptoms, the Saxon test results, Schirmer’s test results, anti-SS-A/Ro antibody positivity, anti-SS-B/La antibody positivity, anti-centromere antibody (ACA) positivity, serum immunoglobulin G levels, and the clinical European League Against Rheumatism SS disease activity index were examined. The ultrasonography (US) score was calculated based on SGUS imaging (hypoechoic area, hyperechoic band, and irregular border) (4).

Results:

The US score was significantly higher in patients with SS than that in non-SS sicca subjects. In addition, we found significant correlations between the US score and FS in patients with SS. Multivariate analysis revealed the FS, Saxon test positivity, and ACA positivity as the variables independently associated with the US score in patients with SS. These results were the same in the primary SS patient group (n=96). Patients with ACA positivity had significantly higher US scores compared to those in patients with ACA negativity, whereas the FS was not significantly high. In addition, patients with ACA positivity had significantly greater positivity of hyperechoic bands than that in patients with ACA negativity.

Conclusion:

This study indicated that ACA positivity, which is not reflected in sialadenitis of SS, is associated with the US score in patients with SS. These results suggest that US findings of patients with ACA positivity might show specific changes in salivary glands, such as fibrosis, and not only sialadenitis (5).

References:

[1]Ramos-Casals M, Tzioufas AG, Font J. Primary Sjogren’s syndrome: new clinical and therapeutic concepts. Ann Rheum Dis. 2005;64(3):347-54.

[2]van Ginkel MS, Glaudemans A, van der Vegt B, Mossel E, Kroese FGM, Bootsma H, et al. Imaging in Primary Sjogren’s Syndrome. J Clin Med. 2020;9(8).

[3]Vitali C, Bombardieri S, Jonsson R, Moutsopoulos HM, Alexander EL, Carsons SE, et al. Classification criteria for Sjogren’s syndrome: a revised version of the European criteria proposed by the American-European Consensus Group. Ann Rheum Dis. 2002;61(6):554-8.

[4]Takagi Y, Nakamura H, Sumi M, Shimizu T, Hirai Y, Horai Y, et al. Combined classification system based on ACR/EULAR and ultrasonographic scores for improving the diagnosis of Sjogren’s syndrome. PLoS One. 2018;13(4):e0195113.

[5]Nakamura H, Kawakami A, Hayashi T, Iwamoto N, Okada A, Tamai M, et al. Anti-centromere antibody-seropositive Sjögren’s syndrome differs from conventional subgroup in clinical and pathological study. BMC Musculoskelet Disord. 2010;11:140.

Disclosure of Interests:

None declared

Long-term survival of a patient with acute neonatal-onset metabolic encephalopathy with carbamoyl phosphate synthetase 1 deficiency

OBJECTIVE

Long-term survival of patients with neonatal-onset carbamoyl-phosphate synthetase 1 deficiency (CPS1D), an autosomal recessive disorder characterized by repeated, life-threatening hyperammonemia, is rare. We describe the diagnosis and clinical management of a teenager with neonatal-onset CPS1D who did not undergo therapeutic liver transplantation.

CASE REPORT

Following emergent neonatal therapy, the patient was diagnosed with CPS1D based on clinical, radiological, biochemical and genetic analyses. Her clinical course, neurobehavioral development and therapeutic interventions are presented and discussed.

RESULTS

Born from nonconsanguineous parents, the proband underwent phototherapy for neonatal jaundice, associated with acute encephalopathy, apnea and cerebral edema. Based on blood and urinary biochemical abnormalities, neonatal-onset CPS1D was diagnosed. Her hyperammonemia was corrected by hemodialysis, followed by sodium benzoate, L-arginine, levocarnitine and protein-free diet therapy. Because of a relapse and persistent neurobehavioral regression by age 1, a planned liver transplantation was cancelled. At age 10, sodium phenylbutyrate was substituted as ammonia scavenger. Genetic testing revealed compound heterozygote c.2359C>T (R787X) and c.236+6T>C variants of CPS1, confirming her diagnosis. Despite severe neurological sequelae, the patient is 16 and in stable condition.

CONCLUSIONS

Our case suggests that early hemodialysis and pharmacologic interventions for acute neonatal hyperammonemia can improve the prognosis of patients with neonatal-onset CPS1D.

Crystal structures of the RNA triphosphatase from Trypanosoma cruzi provide insights into how it recognizes the 5'-end of the RNA substrate

RNA triphosphatase catalyzes the first step in mRNA cap formation, hydrolysis of the terminal phosphate from the nascent mRNA transcript. The RNA triphosphatase from the protozoan parasite Trypanosoma cruzi, TcCet1, belongs to the family of triphosphate tunnel metalloenzymes (TTMs). TcCet1 is a promising antiprotozoal drug target because the mechanism and structure of the protozoan RNA triphosphatases are completely different from those of the RNA triphosphatases found in mammalian and arthropod hosts. Here, we report several crystal structures of the catalytically active form of TcCet1 complexed with a divalent cation and an inorganic tripolyphosphate in the active-site tunnel at 2.20-2.51 Å resolutions. The structures revealed that the overall structure, the architecture of the tunnel, and the arrangement of the metal-binding site in TcCet1 are similar to those in other TTM proteins. On the basis of the position of three sulfate ions that cocrystallized on the positively charged surface of the protein and results obtained from mutational analysis, we identified an RNA-binding site in TcCet1. We conclude that the 5'-end of the triphosphate RNA substrate enters the active-site tunnel directionally. The structural information reported here provides valuable insight into designing inhibitors that could specifically block the entry of the triphosphate RNA substrate into the TTM-type RNA triphosphatases of T. cruzi and related pathogens.

An artificial impact on the asteroid (162173) Ryugu formed a crater in the gravity-dominated regime

The Hayabusa2 spacecraft investigated the small asteroid Ryugu, which has a rubble-pile structure. We describe an impact experiment on Ryugu using Hayabusa2's Small Carry-on Impactor. The impact produced an artificial crater with a diameter >10 meters, which has a semicircular shape, an elevated rim, and a central pit. Images of the impact and resulting ejecta were recorded by the Deployable CAMera 3 for >8 minutes, showing the growth of an ejecta curtain (the outer edge of the ejecta) and deposition of ejecta onto the surface. The ejecta curtain was asymmetric and heterogeneous and it never fully detached from the surface. The crater formed in the gravity-dominated regime; in other words, crater growth was limited by gravity not surface strength. We discuss implications for Ryugu's surface age.

P662 Synchrony between the right and left heart systems is recovered after TAVI in patients with severe aortic stenosis

Funding Acknowledgements

Young Investigator Grant of Japanese Society of Cardiovascular Anesthesia

Background / Introduction

Evidences have shown that cardiac function decline and systolic phase change are caused by massive afterload of the stenosed aortic valve in patients with severe aortic valve stenosis. As a result of the reduction of the left ventricular afterload by valve replacement, the cardiac function recovers. However, it has not been clarified yet how the changes in cardiac function affect the relationship between the right and left heart systems, as well as the systole phase.

TAPSE and MAPSE are known as indices of simple cardiac function evaluation by measuring the movement distance of the atrioventricular annulus. We obtained these indices (i.e. TAPSE, MAPSE) within the same heartbeat using speckle tracking analysis of the atrioventricular annulus and evaluated the changes in cardiac function and phase between the right and left heart systems.

Purpose

To reveal the relationship of cardiac function and time phase between the right and left heart systems by evaluating the maximum movement distance and time of the atrioventricular annulus within the same heartbeat and the same view in patients with severe aortic valve stenosis before and after TAVI.

Methods

A prospective cohort study was conducted. We recruited and analyzed 44 patients with severe aortic valve stenosis who received TAVI treatment, able to record baseline before treatment and follow-up 6 months and 12 months after treatment at our hospital from March 2017 to May 2019. Patients were excluded if more than 2 degree of atrioventricular valve regurgitation or incomplete data. The apical four-chamber view was used for speckle tracking analysis with the origin of the apical extension and region of interest (ROI) of the mitral annulus and tricuspid annulus. For each patient before treatment, at 6 months and 12 months after treatment, the maximum contraction distance (DM), maximum contraction time (TM) of the mitral valve annulus, maximum contraction distance (DT) and maximum contraction time (TT) of the tricuspid annulus were measured. Maximum contraction distance ratio (DM/ DT) and maximum contraction time ratio (TM/ TT) were calculated. For statistical analysis, t-test and ANOVA were used, and a significance threshold of p &lt;0.05 was applied.

Results

TM/ TT decreased at 12 months after TAVI, and DM/ DT increased significantly at 6 months and 12 months after TAVI when compared to baseline before treatment.

Conclusions

In patients with severe aortic valve stenosis, the correction of cardiac function difference between the right and left heart systems occurs from 6 months after TAVI. Moreover, the correction of contraction phase difference between the right and left heart systems at 12 months after TAVI. Thus, the synchrony between the right and left heart system is recovered 12 months after TAVI.

Abstract P662 Figure.

P5301Impacts of lifestyle behavior and shift Work on visceral fat accumulation and progression of atherosclerosis in middle-aged workers

Background

Work style, and particularly shift work, can affect an individual's health through disrupting circadian rhythms. Moreover, lifestyle habits including dietary and exercise routines might be altered by irregular shift hours. We thus hypothesized that an individual's lifestyle including working habits could influence the prevalence of visceral fat obesity and the progression of atherosclerosis.

Purpose

The present study investigated how lifestyle and shift work affect the accumulation of visceral fat and the progression of subclinical atherosclerosis in middle-aged workers.

Methods

This study enrolled employees undergoing their periodic health check-up (n=10883). The Cardio-Ankle Vascular Index (CAVI) was measured to assess arterial stiffness, followed by ultrasound examination and computed tomography imaging to measure carotid intima-media thickness (IMT) and visceral fat area (VFA), respectively. Lifestyle was evaluated by the following items: 1) eating breakfast, 2) nighttime eating, 3) regular exercise, 4) habitual drinking, 5) habitual smoking, 6) sleeping hours, and 7) working hours. With regard to work factors, subjects were categorized into fixed daytime workers or shift workers (including subjects working with an irregular schedule, outside of daytime hours, or at nighttime).

Results

Among all subjects enrolled, 6820 subjects were fixed daytime workers and 4063 subjects were shift workers. Most of the employees engaged in fixed daytime work were clerical workers, while the employees engaged in shift work were mainly physical workers in this company. Fixed daytime workers had significantly greater VFA than shift workers, but the prevalence of metabolic syndrome, CAVI values, and carotid IMT were similar between groups. Reduced regular exercise, long sleeping hours, and fixed daytime work were independently associated with visceral fat accumulation by both multivariate regression and logistic regression analyses. However, the logistic regression analysis with the presence of metabolic syndrome as the endpoint revealed that skipping breakfast, reduced regular exercise, long sleeping hours, and short working hours were independent determinants of metabolic syndrome. On the other hand, univariate and multivariate regression analysis showed that habitual smoking, but not shift work, were significantly associated with CAVI and carotid IMT. Logistic regression analysis with the endpoint of carotid atherosclerosis (presence of plaque) showed that habitual smoking was an independent determinant of carotid atherosclerosis.

Conclusions

Reduced regular exercise, long sleeping hours, and fixed daytime work were significantly associated with visceral fat accumulation, while habitual smoking has a consistent association with the progression of atherosclerosis. These findings support the concept that unhealthy lifestyles should be modified before considering intervention in work styles.

The surface composition of asteroid 162173 Ryugu from Hayabusa2 near-infrared spectroscopy

The near-Earth asteroid 162173 Ryugu, the target of the Hayabusa2 sample-return mission, is thought to be a primitive carbonaceous object. We report reflectance spectra of Ryugu's surface acquired with the Near-Infrared Spectrometer (NIRS3) on Hayabusa2, to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micrometers was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, which is consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.

Utilization of proliferable extracellular amastigotes for transient gene expression, drug sensitivity assay, and CRISPR/Cas9-mediated gene knockout in Trypanosoma cruzi

Trypanosoma cruzi has three distinct life cycle stages; epimastigote, trypomastigote, and amastigote. Amastigote is the replication stage in host mammalian cells, hence this stage of parasite has clinical significance in drug development research. Presence of extracellular amastigotes (EA) and their infection capability have been known for some decades. Here, we demonstrate that EA can be utilized as an axenic culture to aid in stage-specific study of T. cruzi. Amastigote-like property of axenic amastigote can be sustained in LIT medium at 37°C at least for 1 week, judging from their morphology, amastigote-specific UTR-regulated GFP expression, and stage-specific expression of selected endogenous genes. Inhibitory effect of benznidazole and nifurtimox on axenic amastigotes was comparable to that on intracellular amastigotes. Exogenous nucleic acids can be transfected into EA via conventional electroporation, and selective marker could be utilized for enrichment of transfectants. We also demonstrate that CRISPR/Cas9-mediated gene knockout can be performed in EA. Essentiality of the target gene can be evaluated by the growth capability of the knockout EA, either by continuation of axenic culturing or by host infection and following replication as intracellular amastigotes. By taking advantage of the accessibility and sturdiness of EA, we can potentially expand our experimental freedom in studying amastigote stage of T. cruzi.

Optimisation of antithrombin resistance assay as a practical clinical laboratory test: Development of prothrombin activator using factors Xa/Va and automation of assay

INTRODUCTION

Antithrombin resistance (ATR) is a novel thrombotic risk in abnormal prothrombins. A manual ATR assay using Oxyuranus scutellatus (Ox) venom as a prothrombin activator was established for detecting antithrombin-resistant prothrombin. However, this assay was limited because of Ox snake venom availability and its throughput capacity. Here, we have improved the ATR assay using bovine factors Xa and Va (FXa/Va) as prothrombin activators and have optimised assay conditions for an automated instrument (ACL TOP 500).

METHODS

Diluted plasma was incubated with a prothrombin activator mix (phospholipids, CaCl₂ , and bovine FXa/Va), followed by inactivation with antithrombin for 10, 20 and 30 minutes. We added a chromogenic substrate S-2238, and assessed changes in absorbance/min at 405 nm. We also adapted assay conditions for ACL TOP 500.

RESULTS

Optimum conditions for FXa/Va treatment were 6.25% phospholipids, 5 mM CaCL₂ , 0.01 μg/mL FXa and 0.1 μg/mL FVa. ATR assay kinetics with the FXa/Va activator was comparable with that with the Ox activator in heterozygous reconstituted plasma with the recombinant wild-type or antithrombin-resistant prothrombin. Using ACL TOP 500, optimum conditions for the FXa/Va treatment were 10.0% phospholipids, 5 mM CaCl₂ , 0.02 μg/mL FXa and 0.2 μg/mL FVa. The automated ATR assay with the FXa/Va activator demonstrated good detectability for antithrombin-resistant prothrombin in plasma from a heterozygous carrier with prothrombin Yukuhashi or Belgrade.

CONCLUSION

We optimised the ATR assay with the FXa/Va activator and adapted the assay for ACL TOP 500; the assay showed the ability to clearly detect antithrombin-resistant prothrombin in manual and automated procedures.

Crystal structures of U6 snRNA-specific terminal uridylyltransferase

The terminal uridylyltransferase, TUT1, builds or repairs the 3′-oligo-uridylylated tail of U6 snRNA. The 3′-oligo-uridylylated tail is the Lsm-binding site for U4/U6 di-snRNP formation and U6 snRNA recycling for pre-mRNA splicing. Here, we report crystallographic and biochemical analyses of human TUT1, which revealed the mechanisms for the specific uridylylation of the 3′-end of U6 snRNA by TUT1. The O₂ and O₄ atoms of the UTP base form hydrogen bonds with the conserved His and Asn in the catalytic pocket, respectively, and TUT1 preferentially incorporates UMP onto the 3′-end of RNAs. TUT1 recognizes the entire U6 snRNA molecule by its catalytic domains, N-terminal RNA-recognition motifs and a previously unidentified C-terminal RNA-binding domain. Each domain recognizes specific regions within U6 snRNA, and the recognition is coupled with the domain movements and U6 snRNA structural changes. Hence, TUT1 functions as the U6 snRNA-specific terminal uridylyltransferase required for pre-mRNA splicing.

After transcription the 3′-end of U6 snRNA is oligo-uridylylated by the terminal uridylyltransferase TUT1. Here the authors present the crystal structure of human TUT1 and give insights into the mechanism of 3′-end uridylylation by the enzyme.

Clinical and biochemical characterization of the prothrombin Belgrade mutation in a large Serbian pedigree: new insights into the antithrombin resistance mechanism

Essentials Prothrombin Belgrade mutation leads to antithrombin resistance. Clinical and biochemical phenotypes in a large family with this mutation were investigated. In carriers, we detected decreased factor II activity and increased endogenous thrombin potential. Prothrombin Belgrade mutation represents a strong prothrombotic risk factor.

SUMMARY

Background The recently reported c.1787G>A mutation in the prothrombin gene leads to Arg596Gln replacement in the protein molecule (prothrombin Belgrade). This substitution impairs binding of antithrombin to thrombin and results in inherited thrombophilia, known as antithrombin resistance. Objectives We aimed to elucidate the clinical and biochemical characteristics of thrombophilia associated with antithrombin resistance in a large Serbian family with the prothrombin Belgrade mutation. Patients and methods Nineteen family members were investigated, among whom 10 were carriers of the c.1787G>A mutation. In all subjects the clinical phenotype was determined and laboratory investigations of hemostatic parameters were performed. Results Six out of the 10 mutation carriers developed thromboembolic events, mainly deep venous and mesenteric vein thrombosis. The median age of the first thrombotic event was 26.5 (12-41) years, whereas the incidence rate of first thrombosis was 2.2% per year. In all mutation carriers prothrombin activity was significantly decreased in comparison with non-carriers, clearly distinguishing each group. However, the presence of the mutation did not affect the prothrombin antigen level in plasma. The endogenous thrombin potential was significantly increased in all carriers in comparison with non-carriers, indicating the presence of blood hypercoagulability. Interestingly, levels of D-dimer and the F1+2 fragment were similar in both groups. Conclusions Although rare, the prothrombin Belgrade mutation represents strong thrombophilia with early onset of thrombosis in the investigated family. According to our results, decreased prothrombin activity may be a simple screening test for detection of this mutation in thrombotic patients.

Interferometric Scattering Microscopy for the Study of Molecular Motors

Our understanding of molecular motor function has been greatly improved by the development of imaging modalities, which enable real-time observation of their motion at the single-molecule level. Here, we describe the use of a new method, interferometric scattering microscopy, for the investigation of motor protein dynamics by attaching and tracking the motion of metallic nanoparticle labels as small as 20nm diameter. Using myosin-5, kinesin-1, and dynein as examples, we describe the basic assays, labeling strategies, and principles of data analysis. Our approach is relevant not only for motor protein dynamics but also provides a general tool for single-particle tracking with high spatiotemporal precision, which overcomes the limitations of single-molecule fluorescence methods.

The Dipeptide Alanyl-Glutamine Prevents Intestinal Mucosal Atrophy in Parenterally Fed Rats

This study was performed to determine whether the addition of alanyl-glutamine (Ala-Gln) can prevent intestinal mucosal atrophy induced by standard solution of total parenteral nutrition (S-TPN). Forty-one male Sprague-Dawley rats weighing 250 g were randomly divided into four groups: group I was killed after overnight fasting; group II received S-TPN. The other groups received S-TPN supplemented with amino acids other than glutamine (group III) or supplemented with Ala-Gln 2 g/100 mL (group IV); both solutions were isocaloric and isonitrogenous. After 1 week of TPN the rats were killed, and the duodenum, proximal jejunum, mid-small bowel, and distal ileum were obtained for morphologic and functional analysis. Weight gain did not differ significantly among these four groups, and there was no difference in nitrogen balance between groups III and IV. Serum glutamine in group IV (102.8 +/- 13.3 mumol/dL) was significantly increased (p less than .05) compared with groups I, II, and III (66.2 +/- 3.9, 55.7 +/- 7.8, and 61.3 +/- 10.8 mumol/dL, respectively). Mucosal wet weight, protein, RNA, sucrase, and maltase of group IV were significantly increased (p less than .05) compared with groups II and III. Villus height was significantly increased (p less than .05) in the jejunum of group IV rats compared with groups II and III, but not in any other segments of the intestine. No significant changes were observed in crypt depth among all groups. Diamine oxidase in groups II, III, and IV was significantly decreased (p less than .05) compared with group I in all segments except for the ileum.(ABSTRACT TRUNCATED AT 250 WORDS)

Development and analysis of patient-derived xenograft mouse models in intravascular large B-cell lymphoma

Intravascular large B-cell lymphoma (IVLBCL) is a distinct disease entity with the peculiar characteristic that tumor cells proliferate within vessels. Despite recent advances in understanding the disease from clinical aspects, the underlying pathogenesis remains unknown. Here we demonstrate analyses of IVLBCL biology using four xenograft mouse models established from primary IVLBCL samples. In all four models, the main characteristic of IVLBCL tumor cell proliferation within vessels was retained. Time-lapse engraftment analyses revealed that the tumor cells initially engrafted and proliferated in the sinusoids and vessels in the liver and then engrafted and proliferated in multiple organs. Intriguingly, serial passage of tumor cells from the adrenal gland of a transplanted mouse developed from primary patient bone marrow cells into a second mouse showed that the tumor cells mainly distributed into the adrenal gland in the second mouse, implying the existence of clonal selection and/or evolution at engraftment of a specific organ. Gene expression profiling analyses demonstrated that the gene set associated with cell migration was enriched for normal peripheral blood B cells, indicating that inhibition of cell migration might be involved in IVLBCL pathogenesis. In conclusion, the mouse xenograft models described here are essential tools for uncovering IVLBCL biology.

Nanomolar Inhibitors of Trypanosoma brucei RNA Triphosphatase

Eukaryal taxa differ with respect to the structure and mechanism of the RNA triphosphatase (RTPase) component of the mRNA capping apparatus. Protozoa, fungi, and certain DNA viruses have a metal-dependent RTPase that belongs to the triphosphate tunnel metalloenzyme (TTM) superfamily. Because the structures, active sites, and chemical mechanisms of the TTM-type RTPases differ from those of mammalian RTPases, the TTM RTPases are potential targets for antiprotozoal, antifungal, and antiviral drug discovery. Here, we employed RNA interference (RNAi) knockdown methods to show that Trypanosoma brucei RTPase Cet1 (TbCet1) is necessary for proliferation of procyclic cells in culture. We then conducted a high-throughput biochemical screen for small-molecule inhibitors of the phosphohydrolase activity of TbCet1. We identified several classes of chemicals-including chlorogenic acids, phenolic glycopyranosides, flavonoids, and other phenolics-that inhibit TbCet1 with nanomolar to low-micromolar 50% inhibitory concentrations (IC50s). We confirmed the activity of these compounds, and tested various analogs thereof, by direct manual assays of TbCet1 phosphohydrolase activity. The most potent nanomolar inhibitors included tetracaffeoylquinic acid, 5-galloylgalloylquinic acid, pentagalloylglucose, rosmarinic acid, and miquelianin. TbCet1 inhibitors were less active (or inactive) against the orthologous TTM-type RTPases of mimivirus, baculovirus, and budding yeast (Saccharomyces cerevisiae). Our results affirm that a TTM RTPase is subject to potent inhibition by small molecules, with the caveat that parallel screens against TTM RTPases from multiple different pathogens may be required to fully probe the chemical space of TTM inhibition.

IMPORTANCE

The stark differences between the structure and mechanism of the RNA triphosphatase (RTPase) component of the mRNA capping apparatus in pathogenic protozoa, fungi, and viruses and those of their metazoan hosts highlight RTPase as a target for anti-infective drug discovery. Protozoan, fungal, and DNA virus RTPases belong to the triphosphate tunnel metalloenzyme family. This study shows that a protozoan RTPase, TbCet1 from Trypanosoma brucei, is essential for growth of the parasite in culture and identifies, via in vitro screening of chemical libraries, several classes of potent small-molecule inhibitors of TbCet1 phosphohydrolase activity.

Distinct X chromosomal rearrangements in four haemophilia B patients with entire F9 deletion

INTRODUCTION

Haemophilia B is an X-linked bleeding disorder caused by a coagulation factor IX gene (F9) abnormality. Numerous F9 defects have been identified to date; however, only a few with an entire F9 deletion have been reported in detail.

AIM

To elucidate the cause of severe haemophilia B, we investigated the precise X chromosome abnormalities in four Japanese patients who did not show all amplifications in F9-specific PCR.

METHODS

We analysed the patient's genomic DNA using Multiplex ligation-dependent probe amplification (MLPA). To assess the extent of any deletions, we further performed mapping PCRs, inverse PCRs or long-range PCRs and direct sequencing analyses of the X chromosome.

RESULTS

We detected entire F9 deletions in four haemophilia B patients and identified the precise deleted regions of the X chromosome including F9. Patient 1 had a 149-kb deletion with breakpoints 90-kb upstream and 30-kb downstream from F9. Patients 2 and 3 showed 273-kb and 1.19-Mb deletions respectively. Patient 4 had two deleted regions: a 1663-bp deletion 1.34-Mb upstream from F9 and a 7.2-Mb deletion including F9. These distinct breakpoints found in four different patients suggest that the mechanism of X chromosome deletion may be different between individuals. Non-allelic homologous recombination (NAHR), microhomology-mediated break-induced replication (MMBIR) or fork stalling and template switching (FoSTeS) may occur in respective X chromosomes of the four haemophilia B patients analysed.

CONCLUSIONS

We identified diverse X chromosomal rearrangements in four haemophilia B patients, which might be caused by distinct mechanisms of genomic rearrangement.

Visualizing chemical states and defects induced magnetism of graphene oxide by spatially-resolved-X-ray microscopy and spectroscopy

This investigation studies the various magnetic behaviors of graphene oxide (GO) and reduced graphene oxides (rGOs) and elucidates the relationship between the chemical states that involve defects therein and their magnetic behaviors in GO sheets. Magnetic hysteresis loop reveals that the GO is ferromagnetic whereas photo-thermal moderately reduced graphene oxide (M-rGO) and heavily reduced graphene oxide (H-rGO) gradually become paramagnetic behavior at room temperature. Scanning transmission X-ray microscopy and corresponding X-ray absorption near-edge structure spectroscopy were utilized to investigate thoroughly the variation of the C 2p(π*) states that are bound with oxygen-containing and hydroxyl groups, as well as the C 2p(σ*)-derived states in flat and wrinkle regions to clarify the relationship between the spatially-resolved chemical states and the magnetism of GO, M-rGO and H-rGO. The results of X-ray magnetic circular dichroism further support the finding that C 2p(σ*)-derived states are the main origin of the magnetism of GO. Based on experimental results and first-principles calculations, the variation in magnetic behavior from GO to M-rGO and to H-rGO is interpreted, and the origin of ferromagnetism is identified as the C 2p(σ*)-derived states that involve defects/vacancies rather than the C 2p(π*) states that are bound with oxygen-containing and hydroxyl groups on GO sheets.

Prognostic value of tropomyosin-related kinases A, B, and C in gastric cancer

PURPOSE

Tropomyosin-related kinase (Trk) receptors play critical roles in tumor development and are considered attractive targets for cancer therapy. We investigated correlations of the expression of TrkA, TrkB, and TrkC with clinicopathological features and outcomes in gastric cancer.

METHODS

Tumor samples were obtained from 221 patients with gastric cancer who underwent gastrectomy between 2003 and 2007. The expression of TrkA, TrkB, and TrkC was analyzed using immunohistochemical staining. The relationship of their expression to clinicopathological factors and outcomes was assessed.

RESULTS

High expression of TrkA, TrkB, or TrkC was significantly associated with histopathology (p = 0.022, p < 0.001, and p < 0.001). High expression of TrkA was significantly correlated with variables related to tumor progression, including lymph node metastasis (p = 0.024) and distant metastasis or recurrence (p < 0.001). Distant metastasis or recurrence was found in a significantly higher proportion of patients with high expression of TrkC than in those with low expression (p = 0.036). High expression of TrkA was significantly associated with poorer relapse-free survival (RFS) in univariate analysis (p = 0.001). High expression of TrkA or TrkC was significantly associated with poorer disease-specific survival (DSS) in univariate analysis (p < 0.001 and p = 0.008). In multivariate analysis, TrkA was an independent predictor of RFS [hazard ratio (HR), 2.294; 95 % confidence interval (CI), 1.309-4.032; p = 0.004] and DSS (HR, 2.146; 95 % CI, 1.195-3.861; p = 0.011). Expression of TrkB was not associated with RFS or DSS in univariate analysis.

CONCLUSIONS

Our results demonstrated that TrkA expression was associated with tumor progression and poor survival, and was an independent predictor of poor outcomes in gastric cancer patients.