Landscape-Scale Dynamics of Aspen in Rocky Mountain National Park, Colorado

Past studies of quaking aspen in Rocky Mountain National Park suggested that the aspen population is declining due to intensive browsing by elk (Cervus elaphus). These studies were conducted in the elk winter range, an area of intensive elk impact. The elk summer range experiences less intense grazing pressure. We tested the hypothesis that impacts of elk would be greater in the elk winter range than the summer range with landscape-scale data from the Park. The detrimental effects of elk on aspen are highly localized and, at larger spatial scales, elk browsing does not seem to be influencing the aspen population

破裂巨大腎動脈瘤の1例

64歳女, 下腹部不快, 失神発作にて発症したエコー, CTにて腎動脈瘤の破裂を強く疑い, 血管造影にて確診した。この際コイルによる塞栓を試みたが不能で, 腎摘出を行い救命しえたWe report a case of rupture of giant renal artery aneurysm (10 cm diameter) with lower abdominal discomfort and a syncopal attack. The patient was successfully treated by nephrectomy. Rupture of a giant renal artery aneurysm is lethal in most cases and prompt diagnosis is indispensable. As preoperative diagnosis, ultrasonography was useful as it showed the blood flow in the renal artery aneurysm in real-time. CT scan was also useful in determining accurately the size of the aneurysm and extension of hematoma in its surroundings

Axon diameter and intra-axonal volume fraction of the corticospinal tract in idiopathic normal pressure hydrocephalus measured by q-space imaging.

PURPOSE: Previous studies suggest that compression and stretching of the corticospinal tract (CST) potentially cause treatable gait disturbance in patients with idiopathic normal pressure hydrocephalus (iNPH). Measurement of axon diameter with diffusion MRI has recently been used to investigate microstructural alterations in neurological diseases. In this study, we investigated alterations in the axon diameter and intra-axonal fraction of the CST in iNPH by q-space imaging (QSI) analysis. METHODS: Nineteen patients with iNPH and 10 age-matched controls were recruited. QSI data were obtained with a 3-T system by using a single-shot echo planar imaging sequence with the diffusion gradient applied parallel to the antero-posterior axis. By using a two-component low-q fit model, the root mean square displacements of intra-axonal space ( =  axon diameter) and intra-axonal volume fraction of the CST were calculated at the levels of the internal capsule and body of the lateral ventricle, respectively. RESULTS: Wilcoxon's rank-sum test revealed a significant increase in CST intra-axonal volume fraction at the paraventricular level in patients (p<0.001), whereas no significant difference was observed in the axon diameter. At the level of the internal capsule, neither axon diameter nor intra-axonal volume fraction differed significantly between the two groups. CONCLUSION: Our results suggest that in patients with iNPH, the CST does not undergo irreversible axonal damage but is rather compressed and/or stretched owing to pressure from the enlarged ventricle. These analyses of axon diameter and intra-axonal fraction yield insights into microstructural alterations of the CST in iNPH

Radiosensitization by hyperthermia in the chicken B-lymphocyte cell line DT40 and its derivatives lacking nonhomologous end joining and/or homologous recombination pathways of DNA double-strand break repair

Hyperthermia has radiosensitizating effect, which is one of the most important biological bases for its use in cancer therapy with radiation. Although the mechanism of this effect has not been clarified in molecular terms, possible involvement of either one or both of two major DNA double-strand break (DSB) repair pathways, i.e., non-homologous end-joining (NHEJ) and homologous recombination (HR), has been speculated. To test this possibility, we examined chicken B lymphocyte cell line DT40 and its derivatives lacking NHEJ and/or HR: KU70-/-, DNA-PKcs-/-/-, RAD54-/- and KU70-/-/RAD54-/-. Hyperthermic radiosensitization could be seen in all of the mutants, including KU70-/-/RAD54-/-, which lacked both NHEJ and HR. Therefore, hyperthermic radiosensitization cannot be explained simply by the inhibitory effects, if any, on typical NHEJ and/or HR alone. However, in NHEJ-defective KU70-/- and DNA-PKcs-/-/-, consisting of two subpopulations with distinct radiosensitivity, the radiosensitive subpopulation, which is considered cells in G1 and early S, was not sensitized: substantial sensitization was seen only in the radioresistant subpopulation, which is considered cells in late S and G2, capable of repairing DSBs through HR. This observation did not exclude possible involvement of NHEJ in G1 and early S phases and also suggested some inhibitory effects of hyperthermia on HR. Thus, partial contribution of NHEJ and HR in hyperthermic radiosensitization, especially that depending on the cell cycle stages, remains to be considered

Examples of the acquired diffusion weighted images.

<p>Examples of the acquired diffusion weighted images.</p

Results of the measurement of CST axon diameter and intra-axonal volume fraction.

<p>Results of the measurement of CST axon diameter and intra-axonal volume fraction.</p