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A Terashi

Publications and source records attributed to A Terashi.

At least 37 records · Page 2Linked to original sources
PubMed1998

[Usefulness of magnetite as an MRI contrasting agent in an experimental cerebral ischemic model evaluation of injecting time point].

The superacute stage of focal ischemia can be visualized using T2-weighted MRI following the injection of superparamagnetic iron oxide particles (magnetite). In this study we evaluated the optimal time point, i.e. the time producing the strongest signal, for the injection of magnetite using T2-weighted MRI following left parmanent middle cerebral artery occlusion (lt.-PMCAO). Male Sprague-Dawley rats were anesthetized and the left middle cerebral artery (lt.-MCA) was permanently occluded. Magnetite was then injected into the femoral vein after 20 to 30 min of lt.-PMCAO. T2-weighted MR images were taken immediately, and 15 and 30 min after magnetite injection. A high signal area at the region of the lt.-MCA was clearly seen on the T2-weighted MRI immediately after magnetite injection. However, it became less clear after 15 min, and by 30 min could not be distinguished. These results suggest that magnetite should be injected immediately prior to T2-weighted MR imaging during the superacute stage of focal ischemia.

Animals↗
PubMed1998

[Cerebral blood flow of patients with age-associated memory impairment and the early stage of Alzheimer's disease. A study by SPECT using the ARG method].

In order to further understand the pathology of Alzheimer's disease (AD), we have utilized image analysis in diagnosing the early stages of AD in patients with cognitive disorders. CT and MRI, however, have not been feasible since only atrophy is seen and it is difficult to differentiate the changes in AD from age associated changes. In this study we tried to determine whether regional cerebral blood flow (rCBF) measurements using single photon emission CT (SPECT) are feasible for the early diagnosis of AD. Regional CBF (rCBF) was measured using SPECT in three subject groups: Age-associated memory impairment (AAMI. n = 9), mild AD (n = 16), and normal aged patients (mean age = 68.3; n = 20). The subjects were then observed for three years. The region of interest (ROI) for the medial temporal lobe was set at OM-30 degrees to cover the maximum area of the hippocampus. The absolute values of rCBF in the frontal, temporal, and parietal lobes and the cerebellum were significantly lower in the mild AD subjects than in the normal aged subjects. A significant decrease in rCBF was also seen in the medial temporal lobe in both the AD and the AAMI subjects compared to the normal controls. During the three years of follow up, no cases of dementia were seen in the AAMI subjects. However, there were two patients who appeared to have difficulty in adapting to daily life due to amnesia, one with a decrease in rCBF of the medial temporal lobe on the second SPECT, and the other showing a low rCBF the first time. This study suggests that AAMI subjects may comprise both AD and normal subjects. Therefore a more prospective study is needed.

Aged↗
PubMed1998

[An evaluation of ischemic stroke using dynamic contrast enhanced perfusion MRI].

Thrombolytic therapy during the hyperacute stage is important for salvaging dying cerebral tissue. To date, however, accurate non-invasive assessment of an ischemic lesion during the hyperacute stage has not been possible. Perfusion MRI may be the key to the quick diagnosis of ischemic lesions. To assess the feasibility of dynamic contrast enhanced perfusion MRI, echo planar imaging was performed in 10 patients with ischemic stroke. The relative cerebral blood volume (rCBV), mean transit time (MTT), and relative cerebral blood flow(rCBF) were measured based on moment analysis and the gamma variate method. These measurements, however, are not suitable for the detection of cerebral ischemia during the hyperacute stage. Therefore, we additionally studied the changes in a concentration curve (time-delta R* curve) of Gd-DTPA, injected into the median vein of the forearm. From the curve the SUM (delta R*) time to peak and the delta R* peak, which may be calculated quickly, were determined and were compared to rCBV, MTT, and rCBF, respectively. The rCBV and the rCBF in the ischemic regions were less than those in the contralateral healthy regions (p < 0.05), and the MTT in the ischemic regions was longer than that in the contralateral healthy regions (p < 0.05). Additionally, SUM (delta R*) and the delta R* peak in the ischemic regions were less, and the time to peak in the ischemic regions was longer than the value in the contralateral healthy regions (p < 0.05), correlating well to the rCBV, rCBF, and MTT measurements. Also, images of these parameters, depicting the ischemic lesion earlier than conventional T2 weighted images, can be easily made by using an MRI console. These results suggest that the SUM (delta R*), time to peak and the delta R* peak images calculated with dynamic contrast enhanced perfusion MRI may be one of the best techniques for the detection of cerebral ischemic lesions during the hyperacute stage.

Acute Disease↗
PubMed1998

[Association analysis of angiotensin-converting enzyme gene polymorphism with end-stage renal disease].

BACKGROUND: Intron 16 insertion/deletion (I/D) polymorphism in the angiotensin-converting enzyme (ACE) gene may be associated with the progression of renal insufficiency in patients with renal diseases. The objective of this study was to determine whether D allele is a risk factor for the progression of the disease in end-stage renal disease (ESRD) patients. METHODS: Using PCR techniques, genetic analysis of the ACE I/D polymorphism was performed on 326 dialysis patients. We compared the distribution of genotypes and allele frequency of this polymorphism in dialysis patients and the normal Japanese population. The clinical courses of 47 patients were studied retrospectively, and the progression of chronic renal failure using time plots of the reciprocal of serum creatinine (1/Cr) was estimated. RESULTS AND CONCLUSION: The frequencies for II, ID, and DD genotypes were 134, 148 and 44, respectively. The frequency for I allele was 0.64, and for D allele 0.36. These results were similar to the frequencies found in the normal Japanese population. However, patients with polycystic kidney disease (PKD) showed a high frequency for D allele (0.54: p = 0.023 by chi 2 method). In longitudinal courses, we did not find any association between ACE gene polymorphism and the declining rate of renal function. However, in patients with PKD, the DD genotype may influence the clinical course of renal disease.

Adult↗
PubMed1998

[Brain water diffusion coefficients and diffusion anisotropy in non-demented patients with diffuse leuko-araiosis].

PURPOSE: To investigate changes in both water diffusion coefficients and diffusion anisotropy in white matter of non-demented patients with leuko-araiosis using diffusion-weighted MRI. METHODS: Diffusion mapping was performed on 8 non-demented patients with leuko-araiosis, 6 patients with chronic cerebral infarction and 6 healthy volunteers, using a spin-echo sequence with motion probing gradient applied sequentially at two gradient strength settings in three orthogonal directions. The apparent diffusion coefficients (ADC) were calculated from 4 regions of interest located within the frontal and parietal subcortical white matter. The index of diffusion anisotropy (IDA) was calculated from the ADC in three orthogonal directions. (IDA = ADCmax-min/ADCmean x 100). RESULTS: Significantly larger ADC were found within the frontal and parietal subcortical white matter in the non-demented patients with leuko-araiosis (mean = 1.51 +/- 0.36 x 10(-3) mm2/s) and the were also significantly larger in patients with cerebral infarction (mean = 2.12 +/- 0.46 x 10(-3) mm2/s) than in the control group (mean = 1.01 +/- 0.33 x 10(-3) mm2/s). But no significant differences were found in the IDA between the non-demented patients with leuko-araiosis (mean = 43.1 +/- 29.2) and the control group (mean = 46.5 +/- 32.5). CONCLUSION: An increase in extracellular space caused by the loss of axonal fibers and myelin is probably the cause of the higher ADC in periventricular hyperintensity lesions. However, the remaining nerve fibers maintain the anisotropy in the lesions in non-demented patients with leuko-araiosis.

Aged↗
PubMed1998

[Usefulness of magnetite as an MRI contrasting agent in an experimental cerebral ischemic model. Evaluation of lesion detecting time].

Gd-DTPA has a T1 shortening effect that enhances the contrast in MRI and is widely used for the clinical evaluation of CNS diseases, though it is not suitable for the detection of cerebral ischemic regions during the superacute stage. Superparamagnetic iron oxide particles have a T2 shortening effect on relaxation time, reducing signal intensity on T2-weighted MRI in normal cerebral tissue. From this perspective we tested the feasibility of detecting ischemic lesions during the superacute stage using superparamagnetic iron oxide particles-enhanced MRI. Male Sprague-Dawley rats were anesthetized using pentobarbital and the left middle cerebral artery was permanently occluded (lt.-PMCAO) using a modified version of the Koizumi method. After lt.-PMCAO, 100 mumoles Fe/kg, 1 ml/kg magnetite, superparamagnetic iron oxide particles, (magnetite-injected group, n = 9) or physiological saline (vehicle-injected group, n = 9) was injected into the femoral vein. T2-weighted MR images were performed at designated time points immediately after injection of magnetite or vehicle on a 6.34 T MR unit. Additionally, in separate animals coronal sections of the brain were stained with 4% 2, 3, 5 triphenyl-tetrazolium-chloride (TTC) to confirm the infarct region. In the magnetite-injected group, a high signal area at the region of lt.-MCA was visible within-20 to 30 min following lt.-PMCAO, whereas in the vehicle-injected group no high signal ischemic area could be confirmed until 3 h after lt.-PMCAO. Infarction was noticed in the TTC staining 3 h following lt.-PMCAO. In this study magnetite injection allowed the detection of ischemia in the occluded MCA area on T2-weighted MRI during the superacute stage. These results suggest that ischemia during the superacute stage can be evaluated using magnetite enhanced MRI.

Animals↗
PubMed1998

[Remote effect in patients with thalamic stroke. A study using positron emission tomography].

The purpose of this study was to investigate the functional relation between the thalamus and other cortical regions in patients with thalamic stroke from the view of cerebral blood flow (CBF) and the cerebral metabolic rate of oxygen (CMRO2) using positron emission tomography (PET). Twenty patients with thalamic stroke (right lesion = 8, left lesion = 12) and 7 normal controls were studied. Five patients were diagnosed as having thalamic infarction, and 15 (patients were diagnosed) as having thalamic hemorrhage by X-CT and/or MRI scan. Regional cerebral blood flow and cerebral metabolic rate of oxygen were measured by PET using C15O2 and 15O2 steady state inhalation technique. In the left thalamic stroke group, CMRO2 was significantly decreased in the left cingulate, superior frontal, superior temporal, middle temporal, medial occipital, and thalamic regions, compared with the normal control group. In the right thalamic stroke group, CMRO2 was decreased in the left cingulate, medial occipital, right hippocampal, thalamic, and the bilateral cerebellar regions, compared with the normal control group. In the left thalamic stroke group. CBF was decreased significantly in the left cingulate, middle temporal, hippocampal, thalamic, and right cerebellar regions, compared with the normal control group. In the right thalamic stroke group, CBF was significantly decreased in the right hippocampal, thalamic and left cerebellar regions compared with the normal control group. These results indicate that CBF and CMRO2 decrease in some distant regions from thalamic lesions, perhaps due to a disconnection of neuronal fiber. Especially in the left thalamic stroke group, CMRO2 was decreased in the ipsilateral temporal regions. This result suggests that there are more intimate functional fiber connections between the thalamus and temporal cortex in the left hemisphere than in the right hemisphere.

Aged↗
PubMed1998

[Assessment of regional cerebral blood flow in subcortical infarction with aphasia].

We assessed the regional cerebral blood flow (rCBF) in 8 patients with subcortical aphasia and 8 patients with subcortical infarction without aphasia using the N-isopropyl-P-[123I]-iodoamphetamine autoradiography (123I-IMP ARG) method. In this study, we evaluated vermis to left cortex ratio of CBF. In cases of Broca's aphasia (N = 2), CBF was lower in the posterior frontal regions including Broca's area, and more hypoperfused in the posterior frontal and in the posterior temporal regions, including Wernicke's area of total aphasia (N = 2). But, it was not significantly hypoperfused in those regions in the cases of Wernicke's (N = 2) and amnestic aphasia (N = 2). In the subcortical aphasia, global CBF in the left cerebral cortex was lower than that in the right cerebral cortex. However, in the subcortical infarction group without aphasia there was no difference between CBF in the left cerebral cortex and the right cerebral cortex. We conclude that hypoperfusion in the left cerebral cortex was greater than that in the right cerebral cortex and it was probably due to dysfunction of the left cerebral cortex when subcortical infarction occurred with aphasia. Though some types of aphasia were not relative to the dysfunction of the left cerebral cortex.

Aged↗
PubMed1998

[Hypoparathyroidism in maintenance dialysis patients (Pts)--a clinical study].

With the recent development of measurement in intact PTH, increases of hypoparathyroidism and adynamic bone disease have been reported in patients on chronic maintenance dialysis. To clarify the frequency of hypoparathyroidism in maintenance dialysis patients, the present study investigates the relationship between the occurrence of hypoparathyroidism and clinical background, several bone metabolic markers and the bone mineral density. We divided 298 maintenance dialysis patients (HD 270, CAPD 28) without parathyroidectomy into 4 groups based on intact PTH. Group A was absolutely hypo (intact PTH < 60 pg/ml), group B was relatively hypo (60 < or = intact PTH < 160), group C was normal (160 < or = intact PTH < 300), and group D was hyperparathyroidic (300 < or = intact PTH). Groups A and B together accounted for 71.8% of the patients. The mean age in groups A and B was higher than in group D (p < 0.05), and the dialysis duration was shorter (p < 0.01). The concentration of 1, 25 (OH)2D was significantly higher in groups A and B than in group D (p < 0.01), and remarkably higher in group A than in group C. The level of Ca, i-P did not differ among the groups. In our investigation of bone metabolic markers, group D was found to have significantly higher Al-p, intact-BGP, and P 1 PC compared with the other 3 groups (p < 0.01), and the concentration of intact BGP was lower in group A than in groups B and C (p < 0.01). The bone mineral density measured by DEXA did not differ among the groups. The results suggest that, due to multiple factors, the actual occurrence of hypoparathyroidism in maintenance dialysis patients is higher than the predicted occurrence.

Alkaline Phosphatase↗
PubMed1998

[Electroencephalography and prognosis in stroke patients].

Electroencephalography (EEG) and its relationship to prognosis were studied in 105 patients with cerebrovascular disease in the acute to subacute stages. Twenty cases had normal EEG, and most of them recovered well. Fifty-five cases had mildly to moderately abnormal EEG with focal asymmetric or slow waves in the unilateral hemisphere. Among them, 41 cases (75%) recovered to the extent of being capable of independent walking, 38 cases (69%) recovered sufficiently to engage in independent activities of daily livings (ADL) and 42 cases (76%) returned home. On the other hand 30 cases who had severely abnormal EEG with diffuse slow waves in the unilateral or bilateral hemispheres showed a poor prognosis. Among them, 18 cases (60%) were confined to bed, 20 cases (69%) remained in totally dependent ADL, and 4 cases (13%) died. Thus, EEG is shown to reflect well functional recovery in stroke patients.

Activities of Daily Living↗
PubMed1998

[Improvement of insulin sensitivity after renal transplantation measured by a glucose clamp technique].

There is much evidence indicating that indicates end-stage renal failure induces insulin resistance. We examined the effects of renal transplantation on insulin resistance with an insulin clamp technique. Insulin sensitivity and insulin secretion rates were measured in 13 renal transplant patients, 7 hemodialysis patients, and 6 healthy controls. Insulin sensitivity was assessed with the euglycemic insulin clamp technique. The clamp was applied for 120 minutes and the average of the glucose disposal rates measured from 90 to 120 minutes was regarded as insulin sensitivity. There was a significant increase in the glucose disposal rate in the renal transplantation patients (6.67 +/- 1.44 mg/kg/min) compared to the hemodialysis patients (4.54 +/- 1.44 mg/kg/min) (p < 0.05). Also, there was a significant decrease in the glucose disposal rates in the hemodialysis patients (4.45 +/- 1.44 mg/kg/min) compared to the healthy controls (7.25 +/- 2.07 mg/kg/min) (p < 0.05). There was no significant difference in the glucose disposal rates between the renal transplant patients and the healthy controls. However, patients treated with beta-blockers had lower glucose disposal rates compared to patients without beta-blockers (4.67 +/- 1.58 vs 6.67 +/- 1.44 mg/kg/min, p < 0.05). In this study, we found that insulin resistance, shown by the euglycemic insulin clamp technique, was recovered after successful renal transplantation that but, beta-blockers affected insulin resistance. In conclusion shows that, the hyperglycemic clamp technique, although many factors such as medication may affect insulin sensitivity, renal transplantation restores insulin resistance found in renal failure patients, but not insulin secretion.

Adult↗
PubMed1998

Persistent primitive hypoglossal artery complicated by atrial septal defect and congenital intrahepatic shunts.

During early embryogenesis, anastomoses are formed between the carotid artery and the basilar or the vertebral artery, and subsequently, these anastomoses regress. In some cases, these anastomoses remain as persistent carotid-basilar or carotid-vertebral anastomoses. Atrial septal defect (ASD), a communication between the atria at the septal level, is a congenital heart anomaly. Intrahepatic venous shunts between the portal and hepatic veins are very rare and only some are considered congenital. We present the first case report of a patient with an ASD, a persistent primitive hypoglossal artery, and congenital portahepatic shunts.

Aged↗
PubMed1998

Three-dimensional anisotropy contrast (3DAC) magnetic resonance imaging of the human brain: application to assess Wallerian degeneration.

Three-dimensional anisotropy contrast (3DAC) magnetic resonance imaging is a new algorithm for the treatment of apparent diffusion tensor using the three primary colors. To determine if 3DAC has a clinical application for human brain, six normal volunteers and twenty patients with supratentorial cerebrovascular accidents were examined using clinical magnetic resonance imaging (MRI), and the changes in the 3DAC images associated with Wallerian degeneration of the pyramidal tract were evaluated. The 3DAC images exhibited impressive anatomical resolution. In all chronic stage patients with hemiparesis, the colors in the pyramidal tract were faded. Patients examined during the acute stage who later recovered from hemiparesis had no visible changes of the 3DAC image, whereas patients who recovered poorly showed distinct color fading in the pyramidal tract within 14 days following stroke. In conclusion, very fine anatomical structures are visible on 3DAC images, and it can be used as a diagnostic tool for the human brain.

Aged↗
PubMed1998

Effect of prostaglandin E1 on cerebral blood flow in patients with chronic cerebral infarction.

The effect of prostaglandin E1 (PGE1) on cerebral blood flow (CBF) was studied in 10 patients with chronic cerebral infarction. Regional cerebral blood flow (rCBF) was measured by single photon emission computed tomography before and after they received PGE1 120 microg daily for 2 weeks. The rCBF of the brainstem, cerebellum, and frontal, temporal, and parietal lobes increased significantly after PGE1 administration. PGE1 also significantly increased the rCBF of the non-infarcted area adjacent to infarction. The results indicate that PGE1 increases the CBF of patients with chronic cerebral infarction without causing the intracerebral steal phenomenon.

Aged↗
PubMed1998

Influences of supplementary dietary tungsten on methionine metabolism in rabbits fed a low-cholesterol plus methionine diet.

Hyperhomocysteinemia results from an impaired methionine metabolism. Sulfite oxidase, which is an important enzyme in methionine metabolism, contains molybdenum. In contrast, tungsten has a molybdenum-antagonistic effect. Thus, we hypothesized that dietary tungsten may decrease plasma homocysteine levels and influence methionine metabolism. Male New Zealand White rabbits (n=15) were fed a low-cholesterol basal diet and then placed on three different diets: 0.1% cholesterol (Chol), Chol plus 1% methionine (Met), and Chol plus Met plus 0.1% tungsten (W). The animals received these diets for 20 weeks. Biochemical tests of blood and urine were performed. Plasma homocysteine levels were significantly lower in the Chol+Met+W group than in the Chol+Met group. Plasma levels of total cholesterol, triglyceride, lipid peroxide, and urinary 24-h taurine concentrations were higher in the Chol + Met + W group than in the Chol + Met group. In comparison, concentrations of 2, 3-diphosphoglycerate (2, 3-DPG), reduced glutathione (GSH) in erythrocytes, and urinary 24-h SO4(2) were lower in the Chol+Met+W group than in the Chol+Met group. From these results, tungsten could be expected to exhibit an antiatherogenic effect. Conversely, it may have effects on atherogenic factors. Thus, tungsten may play a number of roles in the methionine metabolism.

2,3-Diphosphoglycerate↗
PubMed1997

Effect of long-term administration of ethyl eicosapentate (EPA-E) on local cerebral blood flow and glucose utilization in stroke-prone spontaneously hypertensive rats (SHRSP).

The objective of this study was to determine the effect of ethyl eicosopentate (EPA-E) on local cerebral blood flow (1-CBF) and local glucose utilization (1-CGU) in specific regions of the brain in stroke-prone spontaneously hypertensive rats (SHRSP). EPA-E (100 mg/kg body weight) or saline was orally administered to 8-week-old SHRSP. L-CBF and 1-CGU in the EPA-E-treated, saline-treated, and 8-week-old control rats were measured autoradiographically using 14C-iodoantipyrine and 14C-deoxyglucose (Sakurada's and Sokoloff's methods). The 1-CBF of the saline-treated group decreased significantly with age in all areas measured. EPA-E treatment alleviated the age-dependent decrease in 1-CBF in all areas, especially those in the basal ganglia. The 1-CGU of the saline-treated group did not change with age, however EPA-E treatment increased 1-CGU in all areas measured, though the changes were not significant. EPA-E ameliorated the decrease in cerebral blood flow and improved glucose metabolism in SHRSP suffering from severe hypertension. These results suggest that EPA-E may be useful in the prevention of stroke.

Animals↗
PubMed1997

Ischemic tolerance phenomenon from an approach of energy metabolism and the mitochondrial enzyme activity of pyruvate dehydrogenase in gerbils.

The objective of this study was to determine if the pretreatment with a sublethal ischemic insult, which has been shown to protect against delayed neuronal death, effects the recovery of energy metabolites or alters the activity of pyruvate dehydrogenase (PDH) following transient cerebral ischemia. Gerbils were pretreated with a sublethal ischemic insult, 2 min of bilateral common carotid artery occlusion, and 24 h later given a 5-min lethal ischemic insult. Animals were reperfused for 0, 10, or 60 min, or 1, 3 or 7 days. Brain metabolites, ATP, PCr, and lactate, and PDH activity were measured in the cortex and the hippocampal CA1 region. The pretreatment had no effect on ATP and PCr depletion or on lactate accumulation after the 5-min insult, nor on their recovery up to 1 day reperfusion, although there was a difference in the lactate levels of the non-pretreated and the pretreated gerbils after 10 min reperfusion. The pretreatment also had no effect on PDH activity during ischemia and reperfusion in either region. However, at 3 days reperfusion the non-pretreated animals exhibited a secondary decrease in ATP levels in the hippocampus. At 7 days reperfusion, ATP levels in the hippocampus of both the pretreated animals and the non-pretreated animals were significantly decreased compared to controls. Additionally, the level of ATP in the non-pretreated group was significantly lower than that in the pretreated group. The pretreatment with a sublethal ischemic insult did not effect the initial recovery of metabolites or the activity of PDH following transient cerebral ischemia. However, it protected against the secondary decrease of ATP levels in the hippocampus. Thus, the induction of ischemic tolerance is not caused by a reduction in metabolic impairment during the secondary insult.

Adenosine Triphosphate↗