Hyperpolarized 129Xe MRI using isobutene as a new quenching gas

The use of a quenching gas, isobutene, with a low vapor pressure was investigated to enhance the utility of hyperpolarized ¹²⁹Xe (HP Xe) MRI. Xenon mixed with isobutene was hyperpolarized using a home‐built apparatus for continuously producing HP Xe. The isobutene was then readily liquefied and separated almost totally by continuous condensation at about 173 K, because the vapor pressure of isobutene (0.247 kPa) is much lower than that of Xe (157 kPa). Finally, the neat Xe gas was continuously delivered to mice by spontaneous inhalation. The HP Xe MRI was enhanced twofold in polarization level and threefold in signal intensity when isobutene was adopted as the quenching gas instead of N₂. The usefulness of the HP Xe MRI was verified by application to pulmonary functional imaging of spontaneously breathing mice, where the parameters of fractional ventilation (r_a) and gas exchange (f_D) were evaluated, aiming at future extension to preclinical studies. This is the first application of isobutene as a quenching gas for HP Xe MRI.     

Factors contributing to ribavirin dose reduction due to anemia during interferon alfa2b and ribavirin combination therapy for chronic hepatitis C

Background Recent studies indicate that combination therapy with ribavirin and interferon alfa2b (IFN2b) is effective for chronic hepatitis C virus (HCV) infection. However, reversible hemolytic anemia is a common side effect of this therapy.Methods We determined those factors that contribute to ribavirin dose reduction due to anemia during this treatment by using multiple logistic regression analysis in Japanese patients. The study included 123 patients with chronic hepatitis C (85 male, 38 female; mean age, 50 years; range, 20–70 years), who received 24-week combination therapy. All patients were treated with IFN2b daily for 2 weeks, followed by three times weekly dosing for 22 weeks, with oral ribavirin twice daily, at a total daily dose of 600 or 800mg.Results Of the 123 patients, 34 patients required dose reduction of ribavirin, and 78 patients required no dose reduction. Overall, 20 patients discontinued. On univariate analysis, reduction of the ribavirin dose correlated significantly with pretreatment hemoglobin (Hb) levels of less than 14g/dl, female sex, and patient age 55 years or older. On multivariate analysis, pretreatment Hb of less than 14g/dl level and age 55 years or older were significantly associated with ribavirin dose reduction. The hazard ratios were 3.56 (95% confidence interval [CI], 1.48–8.53) for pretreatment Hb levels of less than 14g/dl, and 2.50 (95% CI, 1.05–5.94) for age 55 years or more.Conclusions Because patient age of 55 years or more, and Hb levels of less than 14g/dl are significant factors that influence ribavirin-induced hemolytic anemia, more careful monitoring is necessary during combination therapy for patients with these risk factors.     

Secure and effective gene delivery system of plasmid DNA coated by polynucleotide

Polynucleotides are anionic macromolecules which are expected to transfer into the targeted cells through specific uptake mechanisms. So, we developed polynucleotides coating complexes of plasmid DNA (pDNA) and polyethylenimine (PEI) for a secure and efficient gene delivery system and evaluated their usefulness. Polyadenylic acid (polyA), polyuridylic acid (polyU), polycytidylic acid (polyC), and polyguanylic acid (polyG) were examined as the coating materials. pDNA/PEI/polyA, pDNA/PEI/polyU, and pDNA/PEI/polyC complexes formed nanoparticles with a negative surface charge although pDNA/PEI/polyG was aggregated. The pDNA/PEI/polyC complex showed high transgene efficiency in B16-F10 cells although there was little efficiency in pDNA/PEI/polyA and pDNA/PEI/polyU complexes. An inhibition study strongly indicated the specific uptake mechanism of pDNA/PEI/polyC complex. Polynucleotide coating complexes had lower cytotoxicity than pDNA/PEI complex. The pDNA/PEI/polyC complex showed high gene expression selectively in the spleen after intravenous injection into mice. The pDNA/PEI/polyC complex showed no agglutination with erythrocytes and no acute toxicity although these were observed in pDNA/PEI complex. Thus, we developed polynucleotide coating complexes as novel vectors for clinical gene therapy, and the pDNA/PEI/polyC complex as a useful candidate for a gene delivery system.     

Rare and Well Done: Endoscopic Control of Colonic Hemorrhage in Severe Ulcerative Colitis

Digestive Diseases and Sciences -     

Transgenic expression of mutant peroxisome proliferator-activated receptor gamma in liver precipitates fasting-induced steatosis but protects against high-fat diet-induced steatosis in mice

Steatosis is one of the most common liver diseases and is associated with the metabolic syndrome. A line of evidence suggests that peroxisome proliferator-activated receptor (PPAR) alpha and PPARgamma are involved in its pathogenesis. Hepatic overexpression of PPARgamma1 in mice provokes steatosis, whereas liver-specific PPARgamma disruption ameliorates steatosis in ob/ob mice, suggesting that hepatic PPARgamma functions as an aggravator of steatosis. In contrast, PPARalpha-null mice are susceptible to steatosis because of reduced hepatic fatty acid oxidation. PPARgamma with mutations in its C-terminal ligand-binding domain (L468A/E471A mutant PPARgamma1) have been reported as a constitutive repressor of both PPARalpha and PPARgamma activities in vitro. To elucidate the effect of co-suppression of PPARalpha and PPARgamma on steatosis, we generated mutant PPARgamma transgenic mice (Liver mt PPARgamma Tg) under the control of liver-specific human serum amyloid P component promoter. In the liver of transgenic mice, PPARalpha and PPARgamma agonist-induced augmentation of the expression of downstream target genes of PPARalpha and PPARgamma, respectively, was significantly attenuated, suggesting PPARalpha and PPARgamma co-suppression in vivo. Suppression of PPARalpha and PPARgamma target genes was also observed in the fasted and high-fat-fed conditions. Liver mt PPARgamma Tg were susceptible to fasting-induced steatosis while being protected against high-fat diet-induced steatosis. The opposite hepatic outcomes in Liver mt PPARgamma Tg as a result of fasting and high-fat feeding may indicate distinct roles of PPARalpha and PPARgamma in 2 different types of nutritionally provoked steatosis.     

Early electrocardiographic indices for predicting chronic doxorubicin-induced cardiotoxicity

BackgroundDealing with chemotherapy-related cardiac dysfunction (CTRCD) remains a significant problem complicated by the difficulty in early detection of cardiotoxicity. Electrocardiogram (ECG) is expected to be the most realistic methodology due to lower cost-performance and non-invasiveness. We investigated the long-term visual fluctuations in the ECG waveforms in patients with chronic doxorubicin (DOX)-induced cardiotoxicity to identify ECG indices for the early detection of cardiotoxicity.MethodsWe conducted a retrospective case series study by reviewing the medical records of 470 consecutive patients with malignant lymphoma who were treated with DOX at our institute between January 2010 and December 2017. Of them, 23 (4.9%) patients developed left ventricular dysfunction and were diagnosed with CTRCD using echocardiography. We assessed the ECG indices on 12-lead ECG recordings before and after treatment in 15 patients; eight patients were excluded due to conduction disturbances or atrial fibrillation.ResultsCTRCD was detected at a median of 475 (interquartile range, IQR: 341–1333) days after initiating chemotherapy. The evaluation of ECG indices preceding CTRCD development was performed 93 (IQR: 52–232) days before the detection of CTRCD. In the stage of CTRCD, the most significant ECG change was T-wave flattening in leads V3–V6 (12 patients, 80%). Additionally, QTa prolongation was observed in leads I and aVL (n = 10, 66%), leads II, III, and aVF (n = 9, 60%), and leads V3–V6 (n = 10, 73%). These ECG changes were not observed before the treatment but were detected mildly in the pre-CTRCD stage, which subsequently worsened in the CTRCD stage.ConclusionsThis study indicated that T-wave changes and QTa prolongation may be useful as an early indicator before the onset of CTRCD in patients with DOX-induced cardiotoxicity.     

Increased DNA-incorporated thiopurine metabolite as a possible mechanism for leukocytopenia through cell apoptosis in inflammatory bowel disease patients with NUDT15 mutation

Journal of Gastroenterology - Polymorphisms in the nucleotide diphosphate-linked moiety X-type motif 15 (NUDT15) gene are associated with thiopurine-induced leukopenia in patients with inflammatory...