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Subacute Stage (subacute + stage)
Selected AbstractsIn vivo measurements of T1 relaxation times in mouse brain associated with different modes of systemic administration of manganese chlorideJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 4 2005Yu-Ting Kuo MD Abstract Purpose To measure regional T1 and T2 values for normal C57Bl/6 mouse brain and changes in T1 after systemic administration of manganese chloride (MnCl2) at 9.4 T. Materials and Methods C57Bl/6 mice were anesthetized and baseline T1 and T2 measurements obtained prior to measurement of T1 after administration of MnCl2 at 9.4 T. MnCl2 was administered systemically either by the intravenous (IV), intraperitoneal (IP), or subcutaneous (SC) routes. T1 and T2 maps for each MRI transverse slice were generated using commercial software, and T1 and T2 values of white matter (WM), gray matter (GM), pituitary gland, and lateral ventricle were obtained. Results When compared with baseline values at low-field, significant lengthening of the T1 values was shown at 9.4 T, while no significant change was seen for T2 values. Significant T1 shortening of the normal mouse brain was observed following IV, IP, and SC administration of MnCl2, with IV and IP showing similar acute effects. Significant decreases in T1 values were seen for the pituitary gland and the ventricles 15 minutes after either IV or IP injection. GM showed greater uptake of the contrast agent than WM at 15 and 45 minutes after either IV or IP injections. Although both structures are within the blood-brain barrier (BBB), GM and WM revealed a steady decrease in T1 values at 24 and 72 hours after MnCl2 injection regardless of the route of administration. Conclusion Systemic administration of MnCl2 by IV and IP routes induced similar time-course of T1 changes in different regions of the mouse brain. Acute effects of MnCl2 administration were mainly influenced by either the presence or absence of BBB. SC injection also provided significant T1 change at subacute stage after MnCl2 administration. J. Magn. Reson. Imaging 2005;21:334,339. © 2005 Wiley-Liss, Inc. [source] Investigation of mechanisms underlying transient T2 normalization in longitudinal studies of ischemic strokeJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 2 2002Shao-Pow Lin PhD Abstract Purpose To determine if the phenomenon of transient normalization of T2 relaxation in the subacute stage of ischemic stroke is associated with either magnetic susceptibility effects secondary to hemorrhage or changes in tissue water content. Materials and Methods We utilized a rat model of transient, focal, cerebral ischemia. The possibility of hemorrhage was evaluated with T2*-weighted (T2*W) imaging and histology. Changes in water content were assessed by brain wet-to-dry weight. Results Susceptibility effects were not evident in T2*W images, and neither red blood cells nor unchelated Fe(III) was found in hematoxylin and eosin (H-E), or Prussian Blue,stained sections, respectively. However, between the peak of T2 contrast and the point of transient T2 normalization, water content consistently decreased by an average of 3%. Conclusion Transient T2 normalization is associated with normalization of water content and can occur without evidence of hemorrhage. J. Magn. Reson. Imaging 2002;15:130,136. © 2002 Wiley-Liss, Inc. [source] Defense mechanism to oxidative DNA damage in glial cellsNEUROPATHOLOGY, Issue 2 2004Takashi Iida Astrocytosis is a sequential morphological change of astrocytic reaction to tissue damage, and is associated with regulation of antioxidant defense mechanisms to reduce oxidative damage. The repair enzymes to oxidative DNA damage, oxidized purine-nucleoside triphosphatase (hMTH1) and a mitochondrial type of 8-oxoguanine DNA glycosylase (hOGG1,2a) in brain tumors and neurons of Alzheimer's disease, were previously reported. In the present study, glial expression of these repair enzymes under such pathological conditions as cerebrovascular diseases and metastatic brain tumors, were investigated. Furthermore, an in-vitro experiment using a glioma cell-line under oxidative stress was performed to verify the immunohistochemical results of post-mortem materials. As a result, hOGG1,2a immunoreactivities in reactive astrocytes were more intense than those to hMTH1. Oligodendrocytes of acute or subacute stage of brain infarction were strongly immunoreactive to both repair enzymes. In-vitro study revealed that, hOGG1,2a is constitutively expressed in both untreated glioma cells and the glioma cells under oxidative stress. However, although no immunoreactivity to hMTH1 was found in the control cells, accumulation of hMTH1 was rapidly induced by oxidative stress. These results indicate that the two repair enzymes to oxidative DNA damage are differentially regulated in glial cells, and that there is a difference in the expression of the repair enzymes between reactive astrocytes and oligodendrocytes. [source] Clinicopathological features of chronic hypersensitivity pneumonitisRESPIROLOGY, Issue 4 2002HIROSHI HAYAKAWA Objective: Only limited information exists concerning the clinical and pathological features of chronic hypersensitivity pneumonitis (HP) in Japan and elsewhere. We present data on clinicopathological features of chronic HP obtained through a Japanese nationwide survey. Methodology: We studied the clinical and pathological findings in 10 patients with chronic HP who underwent surgical lung biopsy or postmortem examination. Results: There were three types of clinical course: six of the 10 patients had persistent symptoms followed by repeated acute episodes; two showed a subacute onset with persistent symptoms; and two exhibited an insidious onset. Five patients made no attempt to avoid antigen exposure and they all had progressive disease. Pathological findings indicated that lesions were mainly centrilobular with or without epithelioid cell granulomas in specimens obtained during the acute or subacute stage. In contrast, most patients in the chronic stage predominantly showed interstitial fibrosis with a usual interstitial pneumonia pattern. Conclusions: The pathological findings of chronic HP depend on the stage of the disease at tissue sampling. [source] Basilar artery atherosclerotic disease is related to subacute lesion volume increase in pontine base infarctionACTA NEUROLOGICA SCANDINAVICA, Issue 2 2009J. S. Kim Background,,, Although basilar artery atherosclerotic disease (BAD) is frequent in patients with pontine base infarction, it remains unknown whether BAD is related to the lesion size or clinical outcome. Methods,,, We studied 56 patients with unilateral pontine base infarction who underwent (i) diffusion-weighted MRI within 48 h after stroke onset and (ii) follow-up MRI and MR angiography in the subacute stage. Neurologic progression was defined as increased National Institutes of Health Stroke Scale score by , 2 during admission. Clinical outcome was dichotomized as good and poor (, 3) according to the modified Rankin Scale at 1 month after stroke onset. Results,,, Twenty-two patients (39%) had BAD and 15 patients (27%) had neurologic progression. Follow-up MRI performed at median 3.5 ± 1.1 days after the initial MRI showed the lesion volume significantly increased (P < 0.001). The BAD was not significantly related to demographic characteristics, risk factors, initial and follow-up lesion volume, neurologic progression and clinical outcome, but was closely related to the subacute increase in lesion volume (P = 0.004 for 20% increase, P = 0.029 for 50% increase). Conclusions,,, BAD is related to subacute increase in lesion volume, but not to ultimate poor clinical outcome in patients with pontine base infarction. [source] | ||||||||||