Nucleosides and Nucleotides. 140. Synthesis and Antileukemic Activity of 5-Carbon-Substituted 1-β-d-Ribofuflranosylimidazole-4-Carboxamides

Abstract

Synthesis of 5-carbon-substituted 1-β-d-ribofuranosylimidazole-4-carboxamides are described. Treatment of 5-iodo derivative 8 with methyl acrylate in the presence of palladium catalyst gave (E)-5-(2-carbomethoxyvinyl)-1-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)imidazole-4-carboxamide (9), followed by appropriate manipulations to afford various 5-carbon-substituted imidazole derivatives 1–7. The antileukemic activities of these imidazole nucleosides are also described.

     

Naemacyclus culmigenus,a newly reported potential pathogen to Miscanthus sinensis,new to Japan

Since the summer of 2010, a discomycete with erumpent apothecia associated with a leaf blight of Miscanthus leaves, were often collected. The morphological characteristics of the fungus suggested it was a member of the Helotiales rather than the Rhytismatales and this was supported by a phylogenetic analysis. Based on a morphological comparison with the type specimen of Naemacyclus culmigenus, currently known from Poaceae (Andropogon and Panicum), it was identified as N. culmigenus, new to Japan. The molecular phylogenetic analysis showed that the generic delimitation of Naemacyclus and related species requires clarification, as does their higher classification within the Leotiomycetes.     

Increase of Circulating CD11b+Gr1+ cells and Recruitment into the Synovium in Osteoarthritic Mice with Hyperlipidemia

Although recent studies suggest that hyperlipidemia is a risk factor for osteoarthritis (OA), the link between OA and hyperlipidemia is not fully understood. As the number of activated, circulating myeloid cells is increased during hyperlipidemia, we speculate that myeloid cells contribute to the pathology of OA. Here, we characterized myeloid cells in STR/Ort mice, a murine osteoarthritis model, under hyperlipidemic conditions. Ratios of myeloid cells in bone marrow, the spleen, and peripheral blood were determined by flow cytometry. To examine the influence of the hematopoietic environment, including abnormal stem cells, on the hematopoietic profile of STR/Ort mice, bone marrow transplantations were performed. The relationship between hyperlipidemia and abnormal hematopoiesis was examined by evaluating biochemical parameters and spleen weight of F₂ animals (STR/Ort x C57BL/6J). In STR/Ort mice, the ratio of CD11b⁺Gr1⁺ cells in spleens and peripheral blood was increased, and CD11b⁺Gr1⁺ cells were also present in synovial tissue. Splenomegaly was observed and correlated with the ratio of CD11b⁺Gr1⁺ cells. When bone marrow from GFP-expressing mice was transplanted into STR/Ort mice, no difference in the percentage of CD11b⁺Gr1⁺ cells was observed between transplanted and age-matched STR/Ort mice. Analysis of biochemical parameters in F₂ mice showed that spleen weight correlated with serum total cholesterol. These results suggest that the increase in circulating and splenic CD11b⁺Gr1⁺ cells in STR/Ort mice originates from hypercholesterolemia. Further investigation of the function of CD11b⁺Gr1⁺ cells in synovial tissue may reveal the pathology of OA in STR/Ort mice.     

Ras guanyl nucleotide releasing protein 2 affects cell viability and cell–matrix adhesion in ECV304 endothelial cells

Ras guanyl nucleotide releasing proteins (RasGRPs) are guanine nucleotide exchange factors that activate Ras and Rap. We recently reported that xrasgrp2, which is a homolog of the human rasgrp2, plays a role in vasculogenesis and/or angiogenesis during early development of Xenopus embryos. However, the function of RasGRP2 in human vascular endothelium remains unknown. Therefore we aimed to analyze the function of human RasGRP2 in vascular endothelial cells. RasGRP2 overexpression did not increase Ras activation. However, it slightly increased Ras expression and increased proliferation in ECV304 cells. Furthermore, RasGRP2 overexpression increased Rap1 activation and cell–matrix adhesion in ECV304 cells. These data demonstrate that RasGRP2 increases cell viability and cell–matrix adhesion through increased Ras expression and Rap1 activation, respectively, in endothelial cells.     

Trail traffic flow prediction by contact frequency among individual ants

Ants build a trail that leads to a new location when they move their colony. The trail’s traffic flows smoothly, regardless of the density on the trail. To the best of our knowledge, such a phenomenon has been reported only for ant species. The trail’s capacity is known as trail traffic flow. In this paper, we propose a probabilistic model of trail traffic flow, which overcomes some inadequacies of the kinetic model previously proposed in the literature. Our model answers a question unsolved by the previous model, namely, how many worker ants form such a density-independent trail. We focus on ants’ responses to mutual contacts that involve individuals in trail formation. We propose a model in which contact frequency predicts the number of worker ants that form a trail. We verify that our model’s estimates match the empirical data that ant experts reported in the literature. In modeling and evaluation, we discuss an intelligent ant species, the house-hunting ant Temnothorax albipennis, which is popular among the ant experts.     

Matrix-Embedded Osteocytes Regulate Mobilization of Hematopoietic Stem/Progenitor Cells

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Crucial Residue Involved in L-Lactate Recognition by Human Monocarboxylate Transporter 4 (hMCT4)

Background

Monocarboxylate transporters (MCTs) transport monocarboxylates such as lactate, pyruvate and ketone bodies. These transporters are very attractive therapeutic targets in cancer. Elucidations of the functions and structures of MCTs is necessary for the development of effective medicine which targeting these proteins. However, in comparison with MCT1, there is little information on location of the function moiety of MCT4 and which constituent amino acids govern the transport function of MCT4. The aim of the present work was to determine the molecular mechanism of L-lactate transport via hMCT4.

Experimental approach

Transport of L-lactate via hMCT4 was determined by using hMCT4 cRNA-injected Xenopus laevis oocytes. hMCT4 mediated L-lactate uptake in oocytes was measured in the absence and presence of chemical modification agents and 4,4′-diisothiocyanostilbene-2,2′-disulphonate (DIDS). In addition, L-lactate uptake was measured by hMCT4 arginine mutants. Immunohistochemistry studies revealed the localization of hMCT4.

Results

In hMCT4-expressing oocytes, treatment with phenylglyoxal (PGO), a compound specific for arginine residues, completely abolished the transport activity of hMCT4, although this abolishment was prevented by the presence of L-lactate. On the other hand, chemical modifications except for PGO treatment had no effect on the transport activity of hMCT4. The transporter has six conserved arginine residues, two in the transmembrane-spanning domains (TMDs) and four in the intracellular loops. In hMCT4-R278 mutants, the uptake of L-lactate is void of any transport activity without the alteration of hMCT4 localization.

Conclusions

Our results suggest that Arg-278 in TMD8 is a critical residue involved in substrate, L-lactate recognition by hMCT4.     

Rates of Serious Intracellular Infections in Autoimmune Disease Patients Receiving Initial Glucocorticoid Therapy

Background/Aims

The Japanese National Hospital Organization evidence-based medicine (EBM) Study group for Adverse effects of Corticosteroid therapy (J-NHOSAC) is a Japanese hospital-based cohort study investigating the safety of the initial use of glucocorticoids (GCs) in patients with newly diagnosed autoimmune diseases. Using the J-NHOSAC registry, the purpose of this observational study is to analyse the rates, characteristics and associated risk factors of intracellular infections in patients with newly diagnosed autoimmune diseases who were initially treated with GCs.

Methodology/Principal Findings

A total 604 patients with newly diagnosed autoimmune diseases treated with GCs were enrolled in this registry between April 2007 and March 2009. Cox proportional-hazards regression was used to determine independent risk factors for serious intracellular infections with covariates including sex, age, co-morbidity, laboratory data, use of immunosuppressants and dose of GCs. Survival was analysed according to the Kaplan-Meier method and was assessed by the log-rank test. There were 127 serious infections, including 43 intracellular infections, during 1105.8 patient-years of follow-up. The 43 serious intracellular infections resulted in 8 deaths. After adjustment for covariates, diabetes (Odds ratio [OR]: 2.5, 95% confidence interval [95% CI] 1.1–5.9), lymphocytopenia (≦1000/μl, OR: 2.5, 95% CI 1.2–5.2) and use of high-dose (≧30 mg/day) GCs (OR: 2.4, 95% CI 1.1–5.3) increased the risk of intracellular infections. Survival curves showed lower intracellular infection-free survival rate in patients with diabetes, lymphocytopaenia and high-dose GCs treatments.

Conclusions/Significance

Patients with newly diagnosed autoimmune diseases were at high risk of developing intracellular infection during initial treatment with GCs. Our findings provide background data on the risk of intracellular infections of patients with autoimmune diseases. Clinicians showed remain vigilant for intracellular infections in patients with autoimmune diseases who are treated with GCs.     

Urinary Fetuin-A Is a Novel Marker for Diabetic Nephropathy in Type 2 Diabetes Identified by Lectin Microarray

We analyzed the urine samples of patients with type 2 diabetes at various stages of diabetic nephropathy by lectin microarray to identify a biomarker to predict the progression of diabetic nephropathy. Japanese patients with type 2 diabetes at various stages of nephropathy were enrolled and we performed lectin microarray analyses (n = 17) and measured urinary excretion of fetuin-A (n = 85). The increased signals of urine samples were observed in Siaα2-6Gal/GalNAc-binding lectins (SNA, SSA, TJA-I) during the progression of diabetic nephropathy. We next isolated sialylated glycoproteins by using SSA-lectin affinity chromatography and identified fetuin-A by liquid chromatography–tandem mass spectrometer. Urinary excretion of fetuin-A significantly increased during the progression of albuminuria (A1, 0.40±0.43; A2, 0.60±0.53; A3 1.57±1.13 ng/gCr; p = 7.29×10⁻⁸) and of GFR stages (G1, 0.39±0.39; G2, 0.49±0.45; G3, 1.25±1.18; G4, 1.34±0.80 ng/gCr; p = 3.89×10⁻⁴). Multivariate logistic regression analysis was employed to assess fetuin-A as a risk for diabetic nephropathy with microalbuminuria or GFR<60 mL/min. Fetuin-A is demonstrated as a risk factor for both microalbuminuria and reduction of GFR in diabetic nephropathy with the odds ratio of 4.721 (1.881–11.844) and 3.739 (1.785–7.841), respectively. Collectively, the glycan profiling analysis is useful method to identify the urine biomarkers and fetuin-A is a candidate to predict the progression of diabetic nephropathy.     

Effect of Caffeine-Containing Beverage Consumption on Serum Alanine Aminotransferase Levels in Patients with Chronic Hepatitis C Virus Infection: A Hospital-Based Cohort Study

Introduction

To date, there have been no prospective studies examining the effect of coffee consumption on serum alanine aminotransferase (ALT) level among individuals infected with the hepatitis C virus (HCV). We conducted a hospital-based cohort study among patients with chronic HCV infection to assess an association between baseline coffee consumption and subsequent ALT levels for 12 months.

Materials and Methods

From 1 August 2005 to 31 July 2006, total 376 HCV-RNA positive patients were recruited. A baseline questionnaire elicited information on the frequency of coffee consumption and other caffeine-containing beverages. ALT level as a study outcome was followed through the patients’ medical records during 12 months. The association between baseline beverage consumption and subsequent ALT levels was evaluated separately among patients with baseline ALT levels within normal range (≤45 IU/L) and among those with higher ALT levels (>45 IU/L).

Results

Among 229 patients with baseline ALT levels within normal range, 186 (81%) retained normal ALT levels at 12 months after recruitment. Daily drinkers of filtered coffee were three times more likely to preserve a normal ALT level than non-drinkers (OR=2.74; P=0.037). However, decaffeinated coffee drinkers had a somewhat inverse effect for sustained normal ALT levels, with marginal significance (OR=0.26; P=0.076). In addition, among 147 patients with higher baseline ALT levels, 39 patients (27%) had ALT reductions of ≥20 IU/L at 12 months after recruitment. Daily drinkers of filtered coffee had a significantly increased OR for ALT reduction (OR=3.79; P=0.034). However, in decaffeinated coffee drinkers, OR could not be calculated because no patients had ALT reduction.

Conclusion

Among patients with chronic HCV infection, daily consumption of filtered coffee may have a beneficial effect on the stabilization of ALT levels.