Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

MRI including diffusion-weighted sequences (DW-MRI) has demonstrated its high sensitivity for acute supratentorial ischemic lesions. In this study we examined the sensitivity of different MRI sequences for the detection of acute brainstem and isolated thalamic infarctions. Diffusion- and T2-weighted MRI of 45 consecutive patients with signs and symptoms of infratentorial and thalamic infarction between 6/1997 and 1/2000 were analysed. The time between the onset of symptoms and the first MRI varied between 2 hours to 7 days with a median of 2 days. MRI repeats were performed in 4 patients in whom the clinical brainstem infarction had not been detected initially. Lesion detectability and size were evaluated for different brainstem and thalamic localizations. An acute brainstem or thalamic infarction as defined by the clinical condition could be identified in all patients by comparison of DW-MRI and T2-weighted images. Pons in farctions were the largest, followed by midbrain and thalamic lesions. Medulla oblongata infarctions were small in comparison. Pons, mid-brain and thalamic infarctions were reliably identified beginning 12 hours after the onset of symptoms. In contrast, detectability of medulla oblongata infarctions varied within the first 24 hours and their overall visibility was worse than that of other brainstem infarctions corresponding to their small size. However, regardless of loca tion, none of the 3 infarctions examined within the first 5 hours after the onset of symptoms could be identified. These lesions were demonstrated in follow-up examinations. In conclusion, pontine, midbrain and thalamic infarctions can reliably be visualized by a combination of DW-MRI and T2-weighted images beginning 12 hours after the ischemic attack. However, sensitivity seems to be lower earlier than 12 hours after ischemia and for medulla oblongata lesions.
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PMID:MRI characteristics of acute and subacute brainstem and thalamic infarctions: value of T2- and diffusion-weighted sequences. 1195 66

To determine the role of nitric oxide (NO) in acute renal failure (ARF), we have studied the time course change activities to activity of nitric oxide synthase (NOS) isoform activities, both calcium dependent and independent NOS, in experimental ischemic ARF. We have also analyzed change activities to activity of the NOS activities in both renal cortex and medulla. Male SD rats (n = 5) were inducted to ARF by ischemia-reperfusion injury and divided into the following groups; Control group (sham operation), Day 0 group, (measurement performed on that day of operation), Day 1 group, (measurement performed one day after induction of ARF), Day 3 group and Day 7 group. Measurement of NOS activity was based on the following principles; NO is synthesized from arginine by nitric oxide synthase (NOS) and NO is converted to NO2(-)/NO3(-)(NOx) by oxidation. Detection of the final metabolite of NO, NOx was done using flow injection method (Griess reaction). The results were, (1) calcium dependent NOS activity in the cortex and medulla decreased, however it increased in the recovery period in the renal cortex (Cortex; Control, 0.941 +/- 0.765, D0, 0.382 +/- 0.271, D1, 0.118 +/- 0.353, D3, 2.030 +/- 0.235, D7, 3.588 +/- 2.706, Medulla; Control, 1.469 +/- 0.531, D0, 0.766 +/- 0.156, D1, 0.828 +/- 0.187, D3, 2.078 +/- 0.094, D7, 1.289 +/- 0.313 micromol NOx produced/mg protein/30 min). (2) On the other hand, iNOS activity increased in the early phase of ARF, both in the cortex and medulla, but returned to control values during the recovery phase in cortex and was maintained at higher levels in the medulla (Cortex; Control, 0.333 +/- 0.250, D0, 0.583 +/- 0.428, D1, 1.167 +/- 0.262, D3, 0.250 +/- 0.077, D7, 0.452 +/- 0.292, Medulla; Control, 0.139 +/- 0.169, D0, 0.279 +/- 0.070, D1, 1.140 +/- 0.226, D3, 0.452 +/- 0.048, D7, 0.625 +/- 0.048 micromol NOx produced/mg protein/30 min). These findings suggest that the role of NOS in ARF are different for the different NOS isoforms and have anatomic heterogeneity.
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PMID:Role of nitric oxide synthase activity in experimental ischemic acute renal failure in rats. 1270 21