Cardiosympathetic neuropathy is independent of cardioparasympathetic neuropathy in patients with non-insulin-dependent diabetes mellitus

The relationship between cardiosympathetic neuropathy and cardioparasympathetic neuropathy was investigated in 103 patients with non-insulin-dependent diabetes mellitus. Cardioparasympathetic nerve function was assessed by comparing electrocardiographically the expiratory and inspiratory R-R interval ratios, during a period of deep breathing, and the coefficients of variation of the R-R intervals. Cardiosympathetic nerve function was assessed by determining the uptake of [123I]metaiodobenzyl guanidine into the myocardium. The results indicate that there is no significant correlation between cardioparasympathetic and cardiosympathetic nerve function.     

Failure mode analysis of AlGaAs/GaAs HBTs using electrostatic discharge method

The failure modes of AlGaAs/GaAs heterojunction bipolar transistors (HBTs) showing increases of base leakage current found during the bias and temperature reliability test have been examined and analysed by using an electrostatic discharge (ESD) method. In the examination for HBT having an emitter of 2 × 20 μm, increases of a base leakage current have been observed when an ESD of around 100 V is applied through a base-emitter junction. Furthermore, increases of a collector leakage current have been observed with the additional ESD of around 150 V. Since no fatal effects for the transistor amplification are found in the high current region, the degradations are concluded to be responsible to the local damages of the base layer at the edge of base-emitter junction. Applying the Wunsch-Bell model to the damaged region, the temperature is estimated to be in a range from 400 to 550°C. It is thought that thermal destruction occurs in a base layer.     

Ring-chain equilibrium in the anionic polymerization of δ-valerolactone

Summary The anionic polymerization of δ-valerolactone in tetrahydrofuran with lithium tert-butoxide was found to give a living ring-chain equilibrium system, in which the cyclic oligomers are produced by back-biting degradation from the initially formed linear polymers. The molar cyclization equilibrium constant for the trimer through hexamer decreased in proportion to −2.5 power of the ring size, in accord with the Jacobson-Stockmayer theory.     

Effect of a residue compound in oxidation of carbon-carbon composites and a natural graphite

The formation of residue compounds of graphite and graphitic carbon-carbon composites with nitric acid markedly increases the gasification rate of these samples.Kinetics and electron paramagnetic resonance (EPR) measurements were performed in three pristine samples and their residue compounds. Activation energies were obtained for both groups and showed a decrease for the most graphitic samples as a result of residue compound formation. Paramagnetic intensity ratios for pristine to residue samples and g-values show an increment in EPR signal as a consequence of electron transfer between the graphite lattice and the nitric acid.Activation energies are related to specific material parameters and the residue compound formation mechanism.     

Helicobacter pylori induces proinflammatory cytokines and major histocompatibility complex class II antigen in mouse gastric epithelial cells

Although Helicobacter pylori has been reported to stimulate the release of various cytokines from gastric tissue, it remains unknown whether normal and nontumorous gastric epithelial cells produce these cytokines. Therefore, in this study, we used a normal mouse gastric surface mucous cell line (GSM06) to determine whether gastric epithelial cells produce proinflammatory cytokines in response to H. pylori. The expression of MHC class II antigen was also examined, to investigate whether gastric epithelial cells participate in the immune response to H. pylori. In the study, GSM06 cells were incubated with H. pylori or its lipopolysaccharide (LPS). Proinflammatory cytokines were detected by Northern and Western blot analysis. The expression of MHC class II antigen was examined by fluorescence activated cell sorter (FACS) analysis. Genetic expression of proinflammatory cytokines such as interleukin-1alpha, tumor necrosis factor-alpha, and cytokine-induced neutrophil chemoattractant-2beta was enhanced by both intact and sonicated H. pylori, but not by H. pylori LPS. The expression of MHC class II antigen was induced by H. pylori more strongly than by interferon-gamma. We conclude that H. pylori induces the expression of proinflammatory cytokines and MHC class II antigen in gastric epithelial cells. Gastric epithelial cells may act as antigen-presenting cells and participate in the immune response to H. pylori infection.     

Histone H3 messenger RNA in situ hybridization for identifying proliferating cells in formalin-fixed rat gastric mucosa

To devise a more sensitive method for identifying proliferative cells in routinely formalin-fixed, paraffin-embedded tissues, we applied an in situ hybridization (ISH) technique for the detection of histone H3 mRNA in rat gastric mucosa and amplified the signal by a silver intensification method. ISH was performed using a Fluorescein-labelled, single-stranded DNA probe for the human histone H3 gene. To determine the optimal conditions for detecting H3 mRNA in rat gastric mucosa, we tested the effect of changing conditions, such as fixation time and digestion time, by a proteinase before hybridization. Next, the proliferation indices obtained using H3 ISH were compared with those obtained using bromodeoxyuridine (BrdU) immunohistochemistry. In normal rat gastric mucosa, H3 ISH- and BrdU-positive cells were confined to the neck region of both fundic and pyloric mucosa. The two labelling indices were almost the same. In all the serial sections studied, H3 ISH-positive cells were almost always BrdU-positive too. Taken together, these results indicate that the H3 ISH technique is useful for the evaluation of proliferative activity in gastric epithelial cells by virtue of its detection of S-phase cells.