Experimental beta-alaninuria induced by (aminooxy)acetate

Experimental beta-alaninuria was induced in rats by injection of (aminooxy)acetate (AOA), a potent inhibitor of aminotransferases, in order to elucidate the pathogenesis of hyper-beta-alaninemia. A 27-fold increase of beta-alanine (BALA) excretion was induced by subcutaneous injection of 1 5 mg of AOA per kg of body weight. A 13-fold and a 9-fold increase of beta-aminoisobutyric acid (BAIBA) and gamma-aminobutyric acid (GABA), respectively, were also induced simultaneously by the AOA injection. Identification of BALA and BAIBA isolated from the rat urine was performed by chromatographic and mass spectrometric analyses. The effects of AOA injection on the tissue levels of these amino acids were also studied. Contents of BALA in the liver and kidney and GABA in the brain increased significantly in response to AOA injection. The present study indicates that BALA transaminase is involved in hyper-beta-alaninemia.</p

High glucose level and angiotensin II type 1 receptor stimulation synergistically amplify oxidative stress in renal mesangial cells

Abstract Oxidative stress in renal mesangial cell causes diabetic glomerular changes. High glucose levels and angiotensin II (Ang II) are known to stimulate superoxide production in renal mesangial cells. However, it has been unclear whether Ang II stimulation and pre-conditioning with high glucose affects the same pathway of superoxide production in renal mesangial cells or not. In this study, we examined the levels of oxidative stress under Ang II stimulation in renal mesangial cells preincubated for six hours at various glucose levels. Intracellular levels of reactive oxidative species (ROS) were measured using dihydroethidium or 5′,6′-chloromethyl- 2′,7′ dichlorodihydro-fluorescein diacetate, which facilitates the detection of intracellular ROS under real-time fluorescent microscope. Ang II-induced elevated intracellular ROS levels were detected only when the cells were pre-incubated with high levels of glucose (13.5 mM, 27.8 mM), but was not detected under normal glucose condition (5.5 mM). Production of Ang II-induced intracellular ROS was higher under pre-treatment with 27.8 mM glucose compared to pretreatment with 13.5 mM glucose level. This ROS production in mesangial cells was induced within several minutes of the initiation of Ang II stimulation under high glucose levels. The production of intracellular ROS was significantly reduced in the presence of angiotensin II type1-receptor (AT1R) antagonist, whereas it was augmented in the presence of angiotensin II type2-receptor antagonist. In conclusion, Ang II-induced oxidative stress was augmented by high glucose levels and ROS levels were further alleviated in the presence of AT1R antagonists

Dynamin 2 Cooperates with Amphiphysin 1 in Phagocytosis in Sertoli Cells

Testicular Sertoli cells highly express dynamin 2 and amphiphysin 1. Here we demonstrate that dynamin 2 is implicated in phosphatidylserine (PS)-dependent phagocytosis in Sertoli cells. Immunofluorescence and dual-live imaging revealed that dynamin 2 and amphiphysin 1 accumulate simultaneously at ruffles. These proteins are specifically bound in vitro. Over-expression of dominant negative dynamin 2 (K44A) inhibits liposome-uptake and leads to the mis-localization of amphiphysin 1. Thus, the cooperative function of dynamin 2 and amphiphysin 1 in PS-dependent phagocytosis is strongly suggested.</p

Characterization of hydrogen peroxide removal reaction by hemoglobin in the presence of reduced pyridine nucleotides

AbstractHydrogen peroxide removal rates by hemoglobin were enhanced in the presence of reduced pyridine nucleotides. The species which had the activity to oxidize pyridine nucleotides was purified from human blood and identified as hemoglobin A. Hydrogen peroxide removal rates by hemoglobin A without reduced pyridine nucleotides at 0.2 mM hydrogen peroxide were 0.87±0.11 μmol/s/g hemoglobin, and the removal rates using 0.2 mM NADH and NADPH were 2.02±0.20 and 1.96±0.31 μmol/s/g hemoglobin, respectively. We deduced that the removal reaction by hemoglobin included formations of methemoglobin and the ferryl radical and reduction of the latter with pyridine nucleotides. The hydrogen peroxide removal ability by hemoglobin was less than that by catalase but was larger than that by glutathione peroxidase-glutathione reductase system at 0.2 mM hydrogen peroxide. Under acatalasemic conditions, it was suggested that NAD(P)H were important factors to prevent the oxidative degradation of hemoglobin

Is a high PTP_T muon of the e+p→μ+Xe^+p \to \mu^+ X event observed at HERA a signature of the stop?

We investigate the $e^+p \to \mu^+ X$ event with high transverse momenta observed at HERA (H1) and show that this event could be interpreted as a signature of the single production of the scalar top quark in a supersymmetric model with $R$-parity breaking interactions. The event topology of the H1 event is rather characteristic and in fact it can be simulated by our specific scenario if we reasonably choose our model parameters to be ({\romannumeral 1}) $m_{{\widetilde{d}},{\widetilde{b}}, {\widetilde{\nu}}}$ ${{\stackrel{>}{\sim}}}$ $1$TeV [$0.8$TeV] for ${\lambda'_{131}}$ $=$ $0.1$ [$0.05$] and ({\romannumeral 2}) $m_{{\widetilde{W}}_{1}}$ ${{\stackrel{<}{\sim}}}$ $150$GeV, $100$GeV ${{\stackrel{<}{\sim}}}$ $m_{{\widetilde{t}}_1}$ ${{\stackrel{<}{\sim}}}$ $200$GeV and ${\lambda'_{131}}$ ${{\stackrel{>}{\sim}}}$ $0.05$.Comment: 8 pages, LaTeX, 4 figures (included in a separate .uu file