A new simply and effective fractionation method for cylindrospermopsin analyses.

A new simply and effective fractionation method for cylindrospermopsin (CYN) analyses was developed. The extract from cells of Cylindrospermopsis raciborskii was resuspended with 0.1 M carbonate buffer at pH 10.5, and pass through the double-cartridges column which was consisted of a styrene polymer cartridge and an anion exchange cartridge. CYN and deoxy-CYN were adsorbed with the anion exchange cartridge. After separation of the anion exchange cartridge, adsorbed compounds were eluted from the cartridge with 50% methanol containing 1% formic acid solution. CYN and deoxy-CYN were selectively condensed in the eluted solution. When CYN was analyzed by LC-photodiode array or LC/MS, only two peaks of CYN and deoxy-CYN were detected quantitatively. The results suggest that the fractionation method is a useful method for CYN analyses and must be utilized for CYN purification.     

Change in Nutritional Status during Hospitalization and Prognosis in Patients with Heart Failure with Preserved Ejection Fraction

The impact of changes in nutritional status during hospitalization on prognosis in patients with heart failure with preserved ejection fraction (HFpEF) remains unknown. We examined the association between changes in the Geriatric Nutritional Risk Index (GNRI) and prognosis during hospitalization in patients with HFpEF stratified by nutritional status on admission. Nutritional status did and did not worsen in 348 and 349 of 697 patients with high GNRI on admission, and in 142 and 143 of 285 patients with low GNRI on admission, respectively. Kaplan–Meier analysis revealed no difference in risk of the composite endpoint, all-cause death, or heart failure admission between patients with high GNRI on admission whose nutritional status did and did not worsen. In contrast, patients with low GNRI on admission whose nutritional status did not worsen had a significantly lower risk of the composite endpoint and all-cause death than those who did. Multivariable analysis revealed that worsening nutritional status was independently associated with a higher risk of the composite endpoint and all-cause mortality in patients with low GNRI on admission. Changes in nutritional status during hospitalization were thus associated with prognosis in patients with malnutrition on admission, but not in patients without malnutrition among those with HFpEF.     

Comparative analyses of the two proliferating cell nuclear antigens from the hyperthermophilic archaeon,Thermococcus kodakarensis

The DNA sliding clamp is a multifunctional protein involved in cellular DNA transactions. In Archaea and Eukaryota, proliferating cell nuclear antigen (PCNA) is the sliding clamp. The ring‐shaped PCNA encircles double‐stranded DNA within its central hole and tethers other proteins on DNA. The majority of Crenarchaeota, a subdomain of Archaea, have multiple PCNA homologues, and they are capable of forming heterotrimeric rings for their functions. In contrast, most organisms in Euryarchaeota, the other major subdomain, have a single PCNA forming a homotrimeric ring structure. Among the Euryarchaeota whose genome is sequenced, Thermococcus kodakarensis is the only species with two genes encoding PCNA homologues on its genome. We cloned the two genes from the T. kodakarensis genome, and the gene products, PCNA1 and PCNA2, were characterized. PCNA1 stimulated the DNA synthesis reactions of the two DNA polymerases, PolB and PolD, from T. kodakarensis in vitro. PCNA2, however, only had an effect on PolB. We were able to disrupt the gene for PCNA2, whereas gene disruption for PCNA1 was not possible, suggesting that PCNA1 is essential for DNA replication. The sensitivities of the Δpcna2 mutant strain to ultraviolet irradiation (UV), methyl methanesulfonate (MMS) and mitomycin C (MMC) were indistinguishable from those of the wild‐type strain.     

Is catheter rupture rare after totally implantable access port implantation via the right internal jugular vein? Report of a case

Catheter rupture after totally implantable access port (TIAP) implantation via the right internal jugular vein is thought to be very rare. We report a case of catheter rupture found 682 days after TIAP surgery in a 52-year-old woman with recurrent right breast cancer. It is possible that chronic stress at the flexure of the catheter induced by neck movements caused the catheter to rupture. Therefore, when inserting a TIAP via the right internal jugular vein, the site of venous puncture should be decided on carefully. Although a fracture of this type is rarely reported in the literature, the incidence of catheter injury of a TIAP inserted via the internal jugular vein at our institute is 1.8 %. This highlights the need to educate and caution medical staff and patients about preventing catheter fracture being caused by external factors.     

Involvement of aldosterone and mineralocorticoid receptors in rat mesangial cell proliferation and deformability

We demonstrated recently that chronic administration of aldosterone to rats induces glomerular mesangial injury and activates mitogen-activated protein kinases including extracellular signal-regulated kinases 1/2 (ERK1/2). We also observed that the aldosterone-induced mesangial injury and ERK1/2 activation were prevented by treatment with a selective mineralocorticoid receptor (MR) antagonist, eplerenone, suggesting that the glomerular mesangium is a potential target for injuries induced by aldosterone via activation of MR. In the present study, we investigated whether MR is expressed in cultured rat mesangial cells (RMCs) and involved in aldosterone-induced RMC injury. MR expression and localization were evaluated by Western blotting analysis and fluorolabeling methods. Cell proliferation and micromechanical properties were determined by [3H]-thymidine uptake measurements and a nanoindentation technique using an atomic force microscope cantilever, respectively. ERK1/2 activity was measured by Western blotting analysis with an anti-phospho-ERK1/2 antibody. Protein expression and immunostaining revealed that MR was abundant in the cytoplasm of RMCs. Aldosterone (1 to 100 nmol/L) dose-dependently activated ERK1/2 in RMCs with a peak at 10 minutes. Pretreatment with eplerenone (10 micromol/L) significantly attenuated aldosterone-induced ERK1/2 phosphorylation. Aldosterone (100 nmol/L) treatment for 30 hours increased [3H]-thymidine incorporation and decreased the elastic modulus, indicating cellular proliferative and deforming effects of aldosterone, respectively. These aldosterone-induced changes in cellular characteristics were prevented by pretreatment with eplerenone or an ERK (MEK) inhibitor, PD988059 (100 micromol/L). The results indicate that aldosterone directly induces RMC proliferation and deformability through MR and ERK1/2 activation, which may contribute to the pathogenesis of glomerular mesangial injury.     

PDE5 inhibitor sildenafil citrate augments endothelium-dependent vasodilation in smokers

Smoking is associated with endothelial dysfunction. The purpose of this study was to determine the effect of sildenafil, an inhibitor of phosphodiesterase type 5 (PDE5), on endothelial function in smokers. We evaluated the forearm blood flow (FBF) responses to acetylcholine (ACh), an endothelium-dependent vasodilator, and to sodium nitroprusside (SNP), an endothelium-independent vasodilator, before and after oral sildenafil administration (100 mg) with a strain-gauge plethysmograph in 10 young healthy male smokers and 10 young healthy male nonsmokers. FBF response to ACh was lower in smokers than in nonsmokers. The vasodilatory effects of SNP were similar in both groups. Sildenafil increased the FBF response to ACh from 9.3+/-2.0 to 12.5+/-3.5 mL/min per 100 mL tissue in smokers and from 12.6+/-5.6 to 19.6+/-8.4 mL/min per 100 mL tissue in nonsmokers, and it increased the response to SNP from 13.3+/-3.9 to 15.1+/-4.3 mL/min per 100 mL tissue in smokers and from 14.8+/-5.2 to 18.4+/-6.0 mL/min/100 mL tissue in nonsmokers (P<0.05 for all). The ratio of maximal ACh-stimulated FBF expressed as a ratio of maximal SNP-stimulated FBF significantly increased after administration of sildenafil in both groups. Infusion of NG-monomethyl-L-arginine, a nitric oxide synthase inhibitor, abolished sildenafil-induced augmentation of the FBF response to ACh in both groups. The findings suggest that endothelial function is impaired in smokers compared with that in nonsmokers, that inhibition of PDE5 by sildenafil significantly increases nitric oxide-mediated vasodilation, and that the activities of PDE5 in smokers and nonsmokers may be similar.     

Post-treatment cell-free DNA as a predictive biomarker in molecular-targeted therapy of hepatocellular carcinoma

Journal of Gastroenterology - Liquid biopsies, particularly those involving circulating tumor DNA (ctDNA), are rapidly emerging as a non-invasive alternative to tumor biopsies. However, clinical...