The Influence of Chronic Cerebral Hypoperfusion on Cognitive Function and Amyloid β Metabolism in APP Overexpressing Mice

Cognitive impairment resulting from cerebrovascular insufficiency has been termed vascular cognitive impairment, and is generally accepted to be distinct from Alzheimer's disease resulting from a neurodegenerative process. However, it is clear that this simple dichotomy may need revision in light of the apparent occurrence of several shared features between Alzheimer's disease and vascular cognitive impairment. Nevertheless, it still remains largely unknown whether the burden of vascular- and Alzheimer-type neuropathology are independent or interdependent. Therefore, we investigated whether chronic cerebral hypoperfusion influences cognitive ability or amyloid β deposition in amyloid precursor protein (APP) overexpressing transgenic mice

Mutual Exclusion Statistics in Exactly Solvable Models in One and Higher Dimensions at Low Temperatures

We study statistical characterization of the many-body states in exactly solvable models with internal degrees of freedom. The models under consideration include the isotropic and anisotropic Heisenberg spin chain, the Hubbard chain, and a model in higher dimensions which exhibits the Mott metal-insulator transition. It is shown that the ground state of these systems is all described by that of a generalized ideal gas of particles (called exclusons) which have mutual exclusion statistics, either between different rapidities or between different species. For the Bethe ansatz solvable models, the low temperature properties are well described by the excluson description if the degeneracies due to string solutions with complex rapidities are taken into account correctly. {For} the Hubbard chain with strong but finite coupling, charge-spin separation is shown for thermodynamics at low temperatures. Moreover, we present an exactly solvable model in arbitrary dimensions which, in addition to giving a perspective view of spin-charge separation, constitutes an explicit example of mutual exclusion statistics in more than two dimensions

Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae

We systematically surveyed period variations of superhumps in SU UMa-type dwarf novae based on newly obtained data and past publications. In many systems, the evolution of superhump period are found to be composed of three distinct stages: early evolutionary stage with a longer superhump period, middle stage with systematically varying periods, final stage with a shorter, stable superhump period. During the middle stage, many systems with superhump periods less than 0.08 d show positive period derivatives. Contrary to the earlier claim, we found no clear evidence for variation of period derivatives between superoutburst of the same object. We present an interpretation that the lengthening of the superhump period is a result of outward propagation of the eccentricity wave and is limited by the radius near the tidal truncation. We interpret that late stage superhumps are rejuvenized excitation of 3:1 resonance when the superhumps in the outer disk is effectively quenched. Many of WZ Sge-type dwarf novae showed long-enduring superhumps during the post-superoutburst stage having periods longer than those during the main superoutburst. The period derivatives in WZ Sge-type dwarf novae are found to be strongly correlated with the fractional superhump excess, or consequently, mass ratio. WZ Sge-type dwarf novae with a long-lasting rebrightening or with multiple rebrightenings tend to have smaller period derivatives and are excellent candidate for the systems around or after the period minimum of evolution of cataclysmic variables (abridged).Comment: 239 pages, 225 figures, PASJ accepte

Cerebral hypoperfusion accelerates cerebral amyloid angiopathy and promotes cortical microinfarcts

Cortical microinfarcts (CMIs) observed in brains of patients with Alzheimer’s disease tend to be located close to vessels afflicted with cerebral amyloid angiopathy (CAA). CMIs in Alzheimer’s disease are preferentially distributed in the arterial borderzone, an area most vulnerable to hypoperfusion. However, the causal association between CAA and CMIs remains to be elucidated. This study consists of two parts: (1) an observational study using postmortem human brains (n = 31) to determine the association between CAA and CMIs, and (2) an experimental study to determine whether hypoperfusion worsens CAA and induces CMIs in a CAA mouse model. In postmortem human brains, the density of CMIs was 0.113/cm2 in mild, 0.584/cm2 in moderate, and 4.370/cm2 in severe CAA groups with a positive linear correlation (r = 0.6736, p < 0.0001). Multivariate analysis revealed that, among seven variables (age, disease, senile plaques, neurofibrillary tangles, CAA, atherosclerosis and white matter damage), only the severity of CAA was a significant multivariate predictor of CMIs (p = 0.0022). Consistent with the data from human brains, CAA model mice following chronic cerebral hypoperfusion due to bilateral common carotid artery stenosis induced with 0.18-mm diameter microcoils showed accelerated deposition of leptomeningeal amyloid β (Aβ) with a subset of them developing microinfarcts. In contrast, the CAA mice without hypoperfusion exhibited very few leptomeningeal Aβ depositions and no microinfarcts by 32 weeks of age. Following 12 weeks of hypoperfusion, cerebral blood flow decreased by 26% in CAA mice and by 15% in wild-type mice, suggesting impaired microvascular function due to perivascular Aβ accumulation after hypoperfusion. Our results suggest that cerebral hypoperfusion accelerates CAA, and thus promotes CMIs

Gravitational Wave Physics and Astronomy in the nascent era

The detections of gravitational waves (GW) by the LIGO/Virgo collaborations provide various possibilities for both physics and astronomy. We are quite sure that GW observations will develop a lot, both in precision and in number, thanks to the continuous work on the improvement of detectors, including the expected new detector, KAGRA, and the planned detector, LIGO-India. On this occasion, we review the fundamental outcomes and prospects of gravitational wave physics and astronomy. We survey the development, focusing on representative sources of gravitational waves: binary black holes, binary neutron stars, and supernovae. We also summarize the role of gravitational wave observations as a probe of new physics

アミロイド前駆体タンパク質過剰発現マウスにおける、慢性脳低灌流の認知機能とアミロイドβ代謝への影響

京都大学0048新制・課程博士博士(医学)甲第15984号医博第3569号新制||医||987(附属図書館)28563京都大学大学院医学研究科医学専攻(主査)教授 福山 秀直, 教授 渡邉 大, 教授 宮本 享学位規則第4条第1項該当Doctor of Medical ScienceKyoto UniversityDA

Study of the Time-Series of Microvariability in Kepler Blazar W2R 1926+42

One of the remarkable features of blazars is violent variability over a wide wavelength range. The variation mechanism causing the observed complex behavior is still under debate. The variability timescales range from less than a day to decades. Variation on timescales less than a day is known as “microvariability.” Such short-term variations can provide insights regarding the origin of the variability after they are distinguished from longer-term variational components. We select about 195 microvariability events from the continuous light curve of blazar W2R 1926+42 with 1-min time resolution obtained by the Kepler spacecraft, and estimate the timescale and amplitude of each event. The rise and decay timescales of the events reveal random variations over short timescales less than a day, but they indicate systematic variations on timescales longer than several days. This result implies that the events are not independent, but rather mutually correlated

Impact of FDG PET in optimizing patient selection for cytoreductive surgery in recurrent ovarian cancer

Purpose To investigate the impact of PET and PET/CT scanning on decision-making in management planning and to identify the optimal setting for selecting candidates for surgery in suspicious recurrent ovarian cancer. Methods A retrospective chart review was performed in patients with possible recurrent ovarian cancer after primary optimal cytoreduction and taxane/carboplatin chemotherapy who had undergone FDG PET or FDG PET/CT scans from July 2002 to August 2008 to help make treatment decisions. The analysis included 44 patients who had undergone a total of 89 PET scans. The positive PET scans were classified as follows. (1) localized (one or two localized sites of FDG uptake), (2) multiple (three or more sites of FDG uptake), (3) diffuse (extensive low-grade activity outlining serosal and peritoneal surfaces). Results Of the 89 PET scans, 52 (58.4 %) led to a change in management plan. The total number of patients in whom cytoreductive surgery was selected as the treatment of choice increased from 12 to 35. Miliary disseminated disease, which was not detected by PET scan, was found in 22.2 % of those receiving surgery. Miliary disseminated disease was detected in 6 of the 12 patients with recurrent disease whose treatment-free interval (TFI) was = 12 months had such disease (P = 0.0031). Conclusion PET or PET/CT is useful for selecting candidates for cytoreductive surgery among patients with recurrent ovarian cancer. To avoid surgical attempts in those with miliary dissemination, patients with a TFI of >= 12 months are the best candidates for cytoreductive surgery