Atsuhiko Suzue

Gene expression of D-amino acid oxidase in cultured rat astrocytes: regional and cell type specific expression

Neuromodulative free D-serine is present in mammalian brain, and localized to type-2 astrocytes in culture. D-amino acid oxidase (DAO) is a flavoenzyme that catalyzes D-amino acids. We examined the DAO gene expression in cultured rat astrocytes by reverse transcriptase-polymerase chain reaction. We established a method to prepare highly purified culture of type-1 and type-2 astrocytes from any brain region. This method utilizes combination of cell type specific separation by shaking and subsequent purification by immunopanning or treatment with cytosine arabinoside. We detected higher DAO gene expression in type-1 astrocyte cultures from cerebellum than that from cerebral cortex. In cerebellum, we observed higher DAO expression in type-1 astrocyte cultures than that in type-2. We also revealed that DAO expression in C6, corresponding to type-1 astrocyte, was higher than that in CG-4 derived type-2 astrocytes.

Elevation of plasma oxidized LDL in acute stroke patients is associated with ischemic lesions depicted by DWI and predictive of infarct enlargement

Abstract oxidized low-density lipoprotein (OxLDL) plays a major role in atherosclerosis. We undertook the present study to clarify the relationship between plasma OxLDL and the ischemic volume. We used ELISA to determine plasma OxLDL levels, and performed diffusion- and perfusionweighted MRI (DWI, PWI) to measure the ischemic volume in 44 ischemic stroke patients. Based on the location of the ischemic lesion, they were divided into three groups: Group I (GI, n=21) had cortical lesions, Group II (GII, n=17) had lesions in the basal ganglia or brain stem, and Group III (GIII, n=6) had massive lesions that involved one entire hemisphere. In GI, but not GII and GIII, plasma OxLDL was significantly higher than in 19 age-matched controls (p<0.01) and was significantly correlated with the initial ischemic volume visualized on DWI (p=0.01), PWI (p<0.01), and the DWI–PWI mismatch (p<0.05). A persistent increase in plasma OxLDL was associated with enlargement of the ischemic lesion in the early phase after the insult. These findings suggest that elevated plasma OxLDL levels are associated with moderate ischemic damage in patients with cortical lesions (GI), but not those with massive hemispheric lesions (GIII), which may be irreversible. In addition, elevated plasma OxLDL may represent a predictor of enlargement of the ischemic lesion.

Plasma proinflammatory and anti-inflammatory cytokine and catecholamine concentrations as predictors of neurological outcome in acute stroke patients

PurposeProinflammatory and anti-inflammatory cytokines may play a pivotal role in cerebral inflammation, which is implicated in the development of brain injury. Systemic cytokine release is mediated by the sympathetic nervous system and catecholamines. The aim of this study was to investigate which parameters, among plasma levels of interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-10 (IL-10), and tumor necrosis factor alpha (TNF-α) and the levels of the catecholamines, epinephrine and norepinephrine, contribute to the clinical outcome in acute stroke patients.MethodsThirty-seven acute stroke patients (ischemic, n = 19; hemorrhagic, n = 18) were enrolled. All of them were admitted to our hospital within 8 h after stroke onset. Neurological status was evaluated by a modified National Institute of Health Stroke Scale (mNIHSS) on admission and by a modified Rankin Scale (mRS) at 1 month. An mRS score of 3 or more at 1 month was considered to indicate poor outcome. Serum samples for the cytokine and catecholamine measurements were collected on admission. Plasma levels of IL-1β, IL-6, IL-10, and TNF-α were determined by an enzyme-linked immunosorbent assay (ELISA) method and epinephrine and norepinephrine concentrations were determined by high-performance liquid chromatography with electrochemical detection (HPLC-EC).ResultsIn the ischemic stroke patients, poor outcome was noted in 9 (47%). There were no significant differences in cytokine or catecholamine concentrations between patients with poor and good outcomes, and there was no association between clinical outcome and cytokine and catecholamine concentrations. In the hemorrhagic stroke patients, poor outcome was noted in 10 (56%). IL-6 and IL-10 levels were higher in patients with poor outcome. On logistic regression analysis, higher values of IL-6 were significantly associated with clinical outcome at 1 month (odds ratio [OR], 1.25; 95% confidence interval [CI], 1.02–1.54).ConclusionIn ischemic stroke, plasma cytokines and catecholamines were not predictors of neurological outcome at 1 month. In hemorrhagic stroke, high levels of IL-6 in the early phase indicated a poor neurological outcome.

The use of continuous hemodiafiltration in a patient with diabetic ketoacidosis.

A variety of fatal complications are associated with diabetes mellitus. Among these, diabetic ketoacidosis (DKA) figures largely in fatalities in young diabetics. Although hyperosmotic diuresis in DKA causes extreme fluid loss, acute renal failure is less common than expected in DKA. We treated a case of severe DKA with associated coma, acute respiratory failure, and acute renal failure in a 24-year-old man who had been diagnosed with type 1 diabetes mellitus at age 19. The comatose patient had been intubated before transfer to our hospital for intensive care. Despite infusion with isotonic saline and insulin, metabolic acidosis was refractory. On day 2, urine output decreased and pulmonary congestion developed, so we started continuous veno-venous hemodiafiltration (CVVHDF), which was effective against the metabolic acidosis; urine output increased gradually. CVVHDF was withdrawn on day 7, and the patients renal function recovered completely. He was discharged from the intensive care unit (ICU) on day 14.

Hemodynamic cerebral ischemia during carotid endarterectomy evaluated by intraoperative monitoring and post-operative diffusion-weighted imaging

Abstract Objective: We used the result of monitoring to evaluate patients with post-operative neurological deficits attributable to hemodynamic cerebral ischemia owing to cross-clamping of the carotid artery. Methods: We evaluated 131 carotid endarterectomy (CEA) procedures performed on 118 patients, 96 men and 22 women ranging in age from 38 to 82 years (mean: 67.1 years). For monitoring, we used a combination of somatosensory evoked potential (SEP), functional dynamic electroencephalography (EEG), near-infrared spectroscopy (NIRS) and transcranial Doppler (TCD). Patients who awoke with neurological deficits after CEA immediately underwent diffusion-weighted imaging (DWI) and magnetic resonance angiography (MRA). Results: In 30 of the 131 procedures (22.9%), intraoperative monitoring disclosed abnormalities after cross-clamping of the internal carotid artery (ICA). In two of these 30 patients, shunt was not introduced, because of full recovery of monitoring after blood pressure increasing, however, one patient demonstrated transient ischemic attack (TIA). In six of remaining 28 patients who need shunt, transient hemodynamic cerebral ischemia occurred, however, all patients recovered gradually within 18 hours after CEA. No new lesions were detected on post-operative DWI of the seven patients and MRA demonstrated good patency of the carotid artery. The other 101 patients whose intraoperative monitoring after cross-clamping of the ICA did not disclose abnormalities demonstrated no hemodynamic TIA. Conclusion: Hemodynamic ischemia owing to cross-clamping of the ICA is rare in patients treated by CEA. However, in patients manifesting neurological deficits upon awakening from CEA, DWI and MRA should be performed immediately to facilitate their prompt treatment.

Elevation of plasma oxidized LDL in acute stroke patients is associated with ischemic lesion depicted by DWI and predictive of infarct enlargement

Oxidized low-density lipoprotein (OxLDL) plays a major role in atherosclerosis. In our previous study, we used specific antibody against oxidized phosphatidylcholine (FOH1a/ DLH3) by which OxLDL is recognized, and first demonstrated the significant association between raised plasma OxLDL and acute cerebral infarction, especially cortical infarction. We undertook the present study to clarify the relationship between plasma OxLDL and the ischemic volume. We used ELISA to determine plasma OxLDL levels and performed diffusion- and perfusion-weighted MRI (DWI, PWI) to measure the ischemic volume in 44 ischemic stroke patients. Based on the location of the ischemic lesion, they were divided into 3 groups: Group I (GI, n=21) had cortical lesions, Group II (GII, n=17) had lesions in the basal ganglia or brain stem, and Group III (GIII, n=6) had massive lesions that involved one entire hemisphere. In GI, but not GII and GIII, plasma OxLDL was significantly higher than in 19 age-matched controls (p<0.01) and was significantly correlated with the initial ischemic volume visualized on DWI (p=0.01), PWI (p<0.01), and the DWI-PWI mismatch (p<0.05)(Figure 1a–c). A persistent increase in plasma OxLDL was associated with enlargement of the ischemic lesion in the early phase after the insult. These findings suggest that elevated plasma OxLDL levels are associated with moderate ischemic damage in patients with cortical lesions (GI) but not those with massive hemispheric lesions (GIII) which may be irreversible. In addition, elevated plasma OxLDL may represent a predictor of enlargement of the ischemic lesion.