Energy Band States of an Oxygen-doped GeSbTe Phase-change Memory Cell; Mechanism of Low-voltage Operation

Phase-change memory is promising because it has a simple structure and has scalability that originates from its unique operating mechanism. However, the programming current should be reduced in accordance with the scaling of cell size [1,2]. We previously reported PCM (Phase Change Memory) cells that operate under 1.5-V/100-μA writing pulses [3, 4]. This PCM had a cell structure composed of 180-nm-W (tungsten) bottom contact to an O-GST (Oxygen-doped GeSbTe) film. Its low-power characteristic is suitable for 0.13-μm generation embedded applications. In the present study, we introduced a new W/O-GST/TaO/W cell structure and found further decrease of programming current the improved stability in the fabrication process. We analyzed the mechanism by which oxygen in GST and the additional TaO layer reduce the power consumption during SET/RESET operations.

Differential effects of propofol and isoflurane on glucose utilization and insulin secretion

AIMS

Volatile anesthetics, such as isoflurane, reverse glucose-induced inhibition of pancreatic adenosine triphosphate-sensitive potassium (K(ATP)) channel activity, resulting in reduced insulin secretion and impaired glucose tolerance. No previous studies have investigated the effects of intravenous anesthetics, such as propofol, on pancreatic K(ATP) channels. We investigated the cellular mechanisms underlying the effects of isoflurane and propofol on pancreatic K(ATP) channels and insulin secretion.

MAIN METHODS

Intravenous glucose tolerance tests (IVGTT) were performed on male rabbits. Pancreatic islets were isolated from male rats and used for a perifusion study, measurement of intracellular ATP concentration ([ATP](i)), and patch clamp experiments.

KEY FINDINGS

Glucose stimulus significantly increased insulin secretion during propofol anesthesia, but not isoflurane anesthesia, in IVGTT study. In perifusion experiments, both islets exposed to propofol and control islets not exposed to anesthetic had a biphasic insulin secretory response to a high dose of glucose. However, isoflurane markedly inhibited glucose-induced insulin secretion. In a patch clamp study, the relationship between ATP concentration and channel activity could be fitted by the Hill equation with a half-maximal inhibition of 22.4, 15.8, and 218.8 μM in the absence of anesthetic, and with propofol, and isoflurane, respectively. [ATP](i) and single K(ATP) channel conductance did not differ in islets exposed to isoflurane or propofol.

SIGNIFICANCE

Our results indicate that isoflurane, but not propofol, decreases the ATP sensitivity of K(ATP) channels and impairs glucose-stimulated insulin release. These differential actions of isoflurane and propofol on ATP sensitivity may explain the differential effects of isoflurane and propofol on insulin release.

Dominant-negative effects of a novel mutation in the filamin myopathy

BACKGROUND

Filamin myopathy is associated with mutations in the filamin C gene (FLNC) and is a myofibrillar myopathy characterized by focal myofibrillar destruction and cytoplasmic aggregates containing several Z-disk-related proteins.

METHODS

This study investigated 6 Japanese patients with dominantly inherited myofibrillar myopathy manifested by adult-onset, slow and progressive muscle weakness and atrophy in the distal extremities.

RESULTS

The abundantly expressed proteins in the affected muscles were identified as filamin C by nano liquid chromatography-tandem mass spectrometry. A genetic analysis of FLNC identified a heterozygous c.8107delG mutation that was localized to the dimerization domain of filamin C. A biochemical crosslinking analysis of bacterially expressed recombinant wild-type and mutant filamin C fragments demonstrated that the mutant monomer disturbed the proper dimerization of the wild-type filamin dimer, resulting in formation of a heterotrimer with the wild-type filamin dimer. The expression study in C2C12 myoblasts showed that the mutant filamin fragments formed cytoplasmic aggregates with endogenous wild-type filamin C.

CONCLUSIONS

This study provides evidence for the dominant-negative effects of the FLNC mutation. These effects may be mutation-specific and likely result in the variation in the clinical phenotypes seen in patients with filamin myopathy.

Concurrence of familial amyotrophic lateral sclerosis with ribbing's disease

We describe a case of familial amyotrophic lateral sclerosis associated with Ribbing's disease. This association has not been previously noted in the literature. The unusual feature of the case was that symptoms coexisted for several years before a correct diagnosis was made. The diagnosis was based on the clinical picture and the result of muscle biopsy and extensive radiographic study. This case serves to illustrate the fact that a separate problem should be considered when the clinical picture is not compatible with the underlying diagnosis.

Muscle morphometry in amyotrophic lateral sclerosis

Quadriceps muscle biopsies from 24 patients with amyotrophic lateral sclerosis (ALS) and 15 age-matched controls were prepared for histochemistry and analyzed morphometrically. Pathological features for denervation and reinnervation were observed in most ALS patients, although considerable variation between patients was noted. Myopathic changes were also seen in one-third of the cases. The morphometric data were not only related to the duration and mean diameter of type I fiber, but also to the duration and hypertrophy factor of type II fiber, suggesting that the progression and severity of ALS depends on the preservation of both fibers.

Expression of G protein-coupled receptor kinase 4 is associated with breast cancer tumourigenesis

G-protein-coupled receptor kinases (GRKs) comprise a family of seven mammalian serine/threonine protein kinases that phosphorylate and regulate agonist-bound, activated, G-protein-coupled receptors (GPCRs). GRKs and beta-arrestins are key participants in the canonical pathways leading to phosphorylation-dependent GPCR desensitization, endocytosis, intracellular trafficking and resensitization. Here we show that GRK4 isoforms are expressed in human breast cancer but not in normal epithelia. In addition, GRK4-over-expressing cells activated the mitogen-activated protein kinase (MAPK) mediated by ERK 1/2 and JNK phosphorylation in breast cancer-derived cell lines. Furthermore, suppression of beta-arrestins decreased GRK4-stimulated ERK 1/2 or JNK phosphorylations. These data indicate that high-level expression of GRK4 may activate MAPK signalling pathways mediated by beta-arrestins in breast cancer cells, suggesting that GRK4 may be implicated in breast cancer carcinogenesis.

HBV genome integration and genetic instability in HBsAg-negative and anti-HCV-positive hepatocellular carcinoma in Japan

The aim of this study is to clarify the existence and the form of HCV RNA and HBV DNA genome integration and genetic instability in liver tissue with HBsAg-negative and anti-HCV-positive HCC. We investigated 16 Japanese patients with HBsAg-negative and anti-HCV-positive HCC. HBV genome integration into host cell genome by Southern hybridization and PCR was examined. Moreover, we analyzed loss of heterozygosity (LOH) and replication errors (RER) of chromosomes 2p, 3p and 17p using the PCR and an autosequencer to determine the three microsatellite regions D2S123, D3S1067, TP53. Eight (50.0%) of 16 were found to have integrated genome of HBV in tumor tissue (T) by PCR. In even the non-tumor regions (NT), seven patients (43.8%) were found to have HBV genome integration. The coincidence between T and NT was found in 4 (25%). Integration of HBV-X gene in T was revealed in three (18.7%), and HBV-integration was confirmed in all NT. No integration of the X gene alone was found in the liver tissue. Five (37.5%) of eight HBV DNA integrated cases simultaneously had HCV RNA minus strand. Concerning the genetic instability, RER were detected in two of 16 (12.5%). RER at 2p; D2S123 was observed in one of 16 (6.2%) and at 3p; D3S1067 was observed in one (6.2%). LOH at the D2S123 locus was observed in one of 12 tumors with heterozygosity (8.3%). There was no genetic instability (LOH or RER) of TP53 which was p53 locus on 17p in T. There was only one case of eight HBV DNA integrated cases (6.2%) with genetic instability of RER of 3p simultaneously in T. In conclusion, the majority of HBsAg-negative and anti-HCV-positive HCC liver tissue was found to have HCV-RNA and HBV DNA integration, and in some samples, HBV DNA integration and genetic instability were concurrently confirmed. It is speculated that multistep carcinogenesis may have been proposed for HCC oncogenetic progression.

Oestrogen-dependent stimulation of luteinising hormone release by galanin-like peptide in female rats

Galanin-like peptide (GALP), a ligand for three types of galanin receptor, is reported to have a role in regulating luteinising hormone (LH) release in male rodents and primates, but its role in LH release in female rodents remains controversial. The present study was conducted to test whether GALP has a stimulatory role in regulating LH secretion in female rats. The effect of i.c.v. infusion of GALP (5 nmol) on pulsatile LH release was investigated in Wistar-Imamichi strain female rats, or lean and obese Zucker rats. In oestradiol-17beta (oestradiol)-primed ovariectomised (OVX) Wistar-Imamichi female rats, i.c.v. infusion of GALP caused a gradual increase in LH release for the first 1.5 h after the infusion followed by an increased LH pulse frequency during the next 1.5 h, resulting in a significant increase in the mean LH concentrations and baseline levels of LH pulses throughout the sampling period and in the frequency of LH pulses at the last half of the period compared to vehicle-treated controls. The stimulatory effect of GALP was oestrogen-dependent because the same GALP treatment did not affect LH release in OVX rats in the absence of oestradiol. In lean Zucker rats, LH pulses were found in oestradiol-primed OVX individuals and central GALP infusion increased mean LH concentrations in the last half of the period. By contrast, few LH pulses were found in oestradiol-primed OVX obese Zucker rats reportedly with lower hypothalamic GALP expression. Central GALP infusion caused an apparent but transient increase in LH release, resulting in the significant increase in all pulse parameters of LH pulses compared to vehicle-treated controls in the first half of the sampling period. These results suggest that hypothalamic GALP is likely involved in stimulating GnRH/LH release, and that the stimulatory effect of GALP on LH release is oestrogen-dependent in female rats.

Topical negative pressure therapy for para-ileostomal ulceration in a patient with Behçet's disease

BehCet's disease is a chronic, relapsing, inflammatory disorder. This case report describes how use of an improvised topical negative pressure (TNP) device in a patient with a non-healing para-ileostomal ulcer with Behçet's disease.