Osteoprotegerinはcollagen生合成と血管平滑筋の増殖を促す事で脳動脈瘤の増大を抑制する

京都大学新制・課程博士博士(医学)甲第23380号医博第4749号京都大学大学院医学研究科医学専攻(主査)教授 山下 潤, 教授 木村 剛, 教授 YOUSSEFIAN Shohab学位規則第4条第1項該当Doctor of Medical ScienceKyoto UniversityDFA

Effect of minor loop on magnetic characteristics of permanent magnet type of MRI

A modeling technique of the minor loop using typical hysteresis loops is shown. The effect of the minor loop and eddy current in the pole piece of a permanent magnet type of MRI on the residual flux density of the probe coil is examined. It is illustrated that the change &#916;B of residual flux density occurs due to the minor loop of the pole piece. It is also pointed out that the choice of time interval &#916;t is important in a nonlinear analysis considering the minor loop</p

Real-time atomic-resolution imaging of crystal growth process in water by phase modulation atomic force microscopy at one frame per second

Recent advancement in dynamic-mode atomic force microscopy (AFM) has enabled its operation in liquid with atomic-scale resolution. However, its imaging speed has often been too slow to visualize atomic-scale dynamic processes. Here, we propose a method for making a significant improvement in the operation speed of dynamic-mode AFM. In this method, we use a wideband and low-latency phase detector with an improved algorithm for the signal complexification. We demonstrate atomic-scale imaging of a calcite crystal growth process in water at one frame per second. The significant improvement in the imaging speed should enable various studies on unexplored atomic-scale interfacial processes. © 2013 AIP Publishing LLC

Ion-specific nanoscale compaction of cysteine-modified poly(acrylic acid) brushes revealed by 3D scanning force microscopy with frequency modulation detection

Stimuli-responsive polyelectrolyte brushes adapt their physico-chemical properties according to pH and ion concentrations of the solution in contact. We synthesized a poly(acrylic acid) bearing cysteine residues at side chains and a lipid head group at the terminal, and incorporated them into a phospholipid monolayer deposited on a hydrophobic silane monolayer. The ion-specific, nanoscale response of polyelectrolyte brushes was detected by using three-dimensional scanning force microscopy (3D-SFM) combined with frequency modulation detection. The obtained topographic and mechanical landscapes indicated that the brushes were uniformly stretched, undergoing a gradual transition from the brush to the bulk electrolyte in the absence of divalent cations. When 1 mM calcium ions were added, the brushes were uniformly compacted, exhibiting a sharper brush-to-bulk transition. Remarkably, the addition of 1 mM cadmium ions made the brush surface significantly rough and the mechanical landscape highly heterogeneous. Currently, cadmium-specific nanoscale compaction of the brushes is attributed to the coordination of thiol and carboxyl side chains with cadmium ions, as suggested for naturally occurring, heavy metal binding proteins

Chotosan (Diaoteng San)-induced improvement of cognitive deficits in senescence-accelerated mouse (SAMP8) involves the amelioration of angiogenic/neurotrophic factors and neuroplasticity systems in the brain

<p>Abstract</p> <p>Background</p> <p>Chotosan (CTS, <it>Diaoteng San</it>), a Kampo medicine (<it>ie </it>Chinese medicine) formula, is reportedly effective in the treatment of patients with cerebral ischemic insults. This study aims to evaluate the therapeutic potential of CTS in cognitive deficits and investigates the effects and molecular mechanism(s) of CTS on learning and memory deficits and emotional abnormality in an animal aging model, namely 20-week-old senescence-accelerated prone mice (SAMP8), with and without a transient ischemic insult (T2VO).</p> <p>Methods</p> <p>Age-matched senescence-resistant inbred strain mice (SAMR1) were used as control. SAMP8 received T2VO (T2VO-SAMP8) or sham operation (sham-SAMP8) at day 0. These SAMP8 groups were administered CTS (750 mg/kg, p.o.) or water daily for three weeks from day 3.</p> <p>Results</p> <p>Compared with the control group, both sham-SAMP8 and T2VO-SAMP8 groups exhibited cognitive deficits in the object discrimination and water maze tests and emotional abnormality in the elevated plus maze test. T2VO significantly exacerbated spatial cognitive deficits of SAMP8 elucidated by the water maze test. CTS administration ameliorated the cognitive deficits and emotional abnormality of sham- and T2VO-SAMP8 groups. Western blotting and immunohistochemical studies revealed a marked decrease in the levels of phosphorylated forms of neuroplasticity-related proteins, N-methyl-D-aspartate receptor 1 (NMDAR1), Ca²⁺/calmodulin-dependent protein kinase II (CaMKII), cyclic AMP responsive element binding protein (CREB) and brain-derived neurotrophic factor (BDNF) in the frontal cortices of sham-SAMP8 and T2VO-SAMP8. Moreover, these animal groups showed significantly reduced levels of vasculogenesis/angiogenesis factors, vascular endothelial growth factor (VEGF), VEGF receptor type 2 (VEGFR2), platelet-derived growth factor-A (PDGF-A) and PDGF receptor α (PDGFRα). CTS treatment reversed the expression levels of these factors down-regulated in the brains of sham- and T2VO-SAMP8.</p> <p>Conclusion</p> <p>Recovery of impaired neuroplasticity system and VEGF/PDGF systems may play a role in the ameliorative effects of CTS on cognitive dysfunction caused by aging and ischemic insult.</p

Acid Dissociation Equilibrium and Singlet Molecular Oxygen Quantum Yield of Acetylated 6,8–Dithioguanosine in Aqueous Buffer Solution

2’,3’,5’–Tri–O–acetyl–6,8–dithioguanosine (taDTGuo) is a modified nucleoside of drug 6–thioguanine and further developed as a potential photochemotherapeutic agent due to its desirable properties of photosensitivity to UVA light and singlet molecular oxygen generation. The photochemical characteristics of taDTGuo under biological conditions (namely in aqueous solution) were intensively investigated by the steady–state absorption and emission, time–resolved near–infrared emission measurements, and quantum chemical calculations. taDTGuo was found to be held in sequential acid dissociation equilibria within pH 3.79–11.93. With the global fitting analysis of the absorption spectra at various pHs, two pKa values of the equilibria were determined to be 7.02 ± 0.01 and 9.79 ± 0.01. Quantum chemical calculations suggested that its mono– and di–anionic species in the ground state should be 1–imide anionic form (N1–taDTGuo–) and 1,7–di–imide anionic form (taDTGuo2–) respectively. taDTGuo generates singlet molecular oxygen effectively and has pH–dependent quantum yields. In conclusion, taDTGuo would be most useful as a potent agent for photochemotherapy under certain carcinomatous pH conditions