Electron Microscopic Recording of Myosin Head Power and Recovery Strokes Using the Gas Environmental Chamber

Despite extensive studies, the amplitude and the mode of the myosin head movement, coupled with ATP hydrolysis, still remain to be a matter for debate and speculation. To obtain direct information about the ATP-coupled myosin head movement, we prepared synthetic myosin filaments (myosin-myosin rod copolymer), in which myosin heads were position-marked with gold particles via antibodies to myosin heads and kept in hydrated, living state in the gas environmental chamber. ATP was applied to the specimen iontophoretically by passing the current to an ATP-containing microelectrode, and the ATP-induced myosin head movement was recorded with an imaging plate system under a magnification of 10,000×, with the following novel findings: (1) In the absence of ATP, myosin heads fluctuate around a definite neutral position. (2) In the absence of actin filaments, myosin heads move away from the bare region of myosin filaments (recovery stroke, average amplitude, 6 nm) on ATP application and return to the neutral position after exhaustion of ATP. (3) In the presence of actin filaments, the ATP-induced myosin head power stroke exhibits two different modes depending on mechanical conditions. (4) Myosin heads determine the direction of ATP-induced movement without being guided by actin filaments

Stress responsive miR-23a attenuates skeletal muscle atrophy by targeting MAFbx /atrogin-1

Muscle atrophy occurs in many pathological states and results primarily from accelerated protein degradation by the ubiquitin-proteasome pathway. We used dexamethasone to induce muscle wasting and investigated the role of a microRNA (miRNA) in the control of muscle-specific E3 ubiquitin ligase MAFbx/atrogin-1. Here we show that miR-23a suppresses MAFbx/atrogin-1 translation by binding to 3'UTR of the mRNA. Furthermore, ectopic expression of miR-23a is sufficient to protect myocytes from atrophy in vitro and in vivo in response to dexamethasone treatment, and heat stress-induced miR-23a protects muscle from dexamethasone-induced muscle atrophy. Our surprising discovery of the physiological role of miR-23a in preventing the atrophy program should lay the basis not only for further understanding of the mechanisms of muscle wasting in diverse diseases, but also for developing novel therapies for these debilitating conditions

For Vol.70, No.5 pp405-408 A Multicenter, Prospective, Randomized Controlled Trial Evaluating the Efficacy of Rectal Diclofenac and Sublingual Nitrate as a Combined Prophylactic Treatment for Post-ERCP Pancreatitis

In the article by Tomoda T et al. entitled “A Multicenter, Prospective, Randomized Controlled Trial Evaluating the Efficacy of Rectal Diclofenac and Sublingual Nitroglycerin as a Combined Prophylactic Treatment for Post-ERCP Pancreatitis”, which appeared in the October 2016 issue, Vol. 70, No. 5, pp405-408, the word “nitroglycerin” should be corrected to “nitrate” throughout the manuscript

The Inhibitory Effect of Kakkonto, Japanese Traditional (Kampo) Medicine, on Brain Penetration of Oseltamivir Carboxylate in Mice with Reduced Blood-Brain Barrier Function

Oseltamivir phosphate (OP) is used to treat influenza virus infections. However, its use may result in central nervous system (CNS) adverse effects. In Japan, OP is used with Kampo formulations to improve clinical effectiveness. We evaluated the potential for using Kampo formulations to reduce CNS adverse effects by quantifying the CNS distribution of oseltamivir and its active metabolite oseltamivir carboxylate (OC) when administered with maoto and kakkonto. We administered lipopolysaccharide (LPS) by intraperitoneal injection to C57BL/6 mice to reduce blood-brain barrier function. Saline, maoto, and kakkonto were administered orally at the same time as LPS. OP was orally administered 4 hours after the last LPS injection and the migration of oseltamivir and OC was examined. Additionally, we examined the brain distribution of OC following intravenous administration. Changes in OC concentrations in the brain suggest that, in comparison to LPS-treated control mice, both Kampo formulations increased plasma levels of OC, thereby enhancing its therapeutic effect. Additionally, our findings suggest kakkonto may not only improve the therapeutic effect of oseltamivir but also reduce the risk of CNS-based adverse effects. Considering these findings, it should be noted that administration of kakkonto during periods of inflammation has led to increased OAT3 expression

Inhibitory effects of caraway (Carum carvi L.) and its component on N -methyl-N ’-nitro-N -nitrosoguanidineinduced mutagenicity

To elucidate the mechanism of antimutagenicity of caraway, we examined the effects of caraway seed extract on N-methyl-N’-nitro-N-nitrosoguanidine (MNNG)-induced mutagenesis in DNA methyltransferase-deficient Salmonella typhimurium strains, O6-methylguanineDNA adduct formation, and thiol content in S. typhimurium cells. MNNG was highly mutagenic for ogt－ strains YG7104(ogt－ ada＋) and YG7108 (ogt－ada－), and it showed slightly higher mutagenicity in strain YG7100 (ogt＋ ada－) than in strains TA100 and TA1535. Hot water extract of caraway seeds inhibited MNNG-induced mutation only in the ogt＋ strains. In the presence of caraway extract, O6-methylguanine DNA adducts in strain YG7100 were decreased in proportion to the decrease of MNNG-induced mutagenesis. Although MNNG is known to degrade in the presence of thiols to produce methyl cation which can react with DNA, caraway had no effect on cellular concentrations of acid-soluble thiols. These results indicate that caraway does not directly inactivate MNNG and that Ogt-O6-methylguanine-DNAmethyltransferasemay be involved in the antimutagenic activity of caraway

Identification of novel clostridium perfringens type E strains that carry an iota toxin plasmid with a functional enterotoxin gene

Clostridium perfringens enterotoxin (CPE) is a major virulence factor for human gastrointestinal diseases, such as food poisoning and antibiotic associated diarrhea. The CPE-encoding gene (cpe) can be chromosomal or plasmid-borne. Recent development of conventional PCR cpe-genotyping assays makes it possible to identify cpe location (chromosomal or plasmid) in type A isolates. Initial studies for developing cpe genotyping assays indicated that all cpe-positive strains isolated from sickened patients were typable by cpe-genotypes, but surveys of C. perfringens environmental strains or strains from feces of healthy people suggested that this assay might not be useful for some cpe-carrying type A isolates. In the current study, a pulsed-field gel electrophoresis Southern blot assay showed that four cpe-genotype untypable isolates carried their cpe gene on a plasmid of ~65 kb. Complete sequence analysis of the ~65 kb variant cpe-carrying plasmid revealed no intact IS elements and a disrupted cytosine methyltransferase (dcm) gene. More importantly, this plasmid contains a conjugative transfer region, a variant cpe gene and variant iota toxin genes. The toxin genes encoded by this plasmid are expressed based upon the results of RT-PCR assays. The ~65 kb plasmid is closely related to the pCPF4969 cpe plasmid of type A isolates. MLST analyses indicated these isolates belong to a unique cluster of C. perfringens. Overall, these isolates carrying a variant functional cpe gene and iota toxin genes represent unique type E strains. © 2011 Miyamoto et al

A Multicenter, Prospective, Randomized Controlled Trial Evaluating the Efficacy of Rectal Diclofenac and Sublingual Nitroglycerin as a Combined Prophylactic Treatment for Post-ERCP Pancreatitis

Acute pancreatitis is the major complication of endoscopic retrograde cholangiopancreatography (ERCP). A preliminary research suggested that the administration of nonsteroidal anti-inflammatory drugs (NSAIDs) with nitroglycerin might reduce the incidence of post-ERCP pancreatitis (PEP) more effectively than NSAIDs alone. We conduct a two-arm, multicenter, prospective, randomized, superiority trial to evaluate the additional effect of nitroglycerin for prevention of PEP. A total of 900 patients randomly receive 50 mg diclofenac suppository either alone or with 5 mg isosorbide dinitrate sublingual tablet. The primary endpoint is the occurrence of PEP. This study will clarify whether NSAIDs plus nitroglycerin can prevent PEP

Diagnosing Pancreatic Tumors Using Contrast-enhanced Harmonic Endoscopic Ultrasonography with Sonazoid

Contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) with contrast agent enabled us to assess the hemodynamics closely, despite limited data in pancreatic tumors. We have initiated a prospective, single arm, and non-randomized study to clarify the accuracy and safety of CH-EUS with Sonazoid and time-intensity curve (TIC) analysis for diagnosing benign or malignant pancreatic tumors. A total of 200 patients will undergo CH-EUS and TIC analysis. Receiver operating characteristic (ROC) analysis will be used to determine the optimal parameter cutoff values for TIC analysis. This will clarify whether CH-EUS and TIC can further improve the diagnosis of pancreatic tumors over conventional EUS

Solitary Peutz-Jeghers type hamartomatous polyps in the duodenum are not always associated with a low risk of cancer: two case reports

INTRODUCTION: A hamartomatous polyp without associated mucocutaneous pigmentation or a family history of Peutz-Jeghers Syndrome is diagnosed as a solitary Peutz-Jeghers type hamartomatous polyp. As compared with Peutz-Jeghers Syndrome, Peutz-Jeghers type hamartomatous polyps are diagnosed with a lower risk of cancer and are regarded as a different disorder. CASE PRESENTATION: In case one, we describe an 84-year-old Japanese man with a 14 mm duodenal polyp. Endoscopic mucosal resection was performed and histological examination showed findings suggestive of a hamartomatous polyp with a focus of well-differentiated adenocarcinoma. In case two, we describe a 76-year-old Japanese man who had been treated for prostate, rectal and lung cancer. Upper gastrointestinal endoscopy revealed a duodenal polyp measuring 15 mm in diameter. Endoscopic mucosal resection was performed, and histological examination showed findings suggestive of a hamartomatous polyp. Liver and thyroid cancers were found after the endoscopic treatment. CONCLUSION: Although duodenal solitary hamartomatous polyps are associated with a lower risk of cancer, four patients, including our cases, have been diagnosed with cancerous polyps. Patients with duodenal solitary hamartomatous polyps should be treated by endoscopic or surgical resection and need whole-body screening