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Biomedical subjects

K Meguro

Publications and source records attributed to K Meguro.

At least 73 records · Page 4Linked to original sources
PubMed1998

[Management of putaminal hemorrhage in patients with chronic renal failure].

The treatments of putaminal hemorrhages (PH) were evaluated in 14 patients (15 hematomas) with chronic renal failure (CRF). We compared the data of our series with the data of co-operative study (1990) on PH. With regard to consciousness level (Neurological Grading, NG) and hematoma volume, significantly more serious cases were observed in PH with CRF than in PH of the co-operative study. In PH with CRF, mortality (40%) was significantly higher than that in PH of the co-operative study. However, the mortality rate was 0%, 0%, 20%, and 100% in NG1, 2, 3, and over 4b. The mortality rate was 0% in non-surgically treated cases with 0 to 30 ml of hematoma volume, and 0% in surgically treated cases with 10 to 50 ml of hematoma volume. These mortality rates were equal to those of the co-operative study with the same NG, and equal to those of the co-operative study with the same hematoma volume. With respect to functional prognosis, "good" (ADL1 and 2) resulted in 67% of non-surgically treated cases with NG1 to 2, and in 33% of surgically treated cases with NG3 to 4a. "Good" resulted in 33% of non-surgically treated cases with 0 to 30 ml of hematoma volume, and in 40% of surgically treated cases with 10 to 50 ml of hematoma volume. These morbidity rates were equal to those of the co-operative study with the same NG, and equal to those of the co-operative study with the same hematoma volume. Therefore, the high mortality in PH with CRF was suspected to be due to the fact that, in our study, there was a higher distribution of serious cases. These findings indicate that protection against enlargement of hematomas in the acute phase may bring about improvement of prognosis in PH with CRF.

Cerebral Hemorrhage↗
PubMed1997

MRI of an infant with Fisher syndrome.

A 15-month-old female infant with nystagmus, gait disturbance, diminished reflexes, ophthalmoplegia, and facial paresis was diagnosed as having Fisher syndrome. Magnetic resonance imaging revealed a transient, high-signal-intensity lesion on the left side of the cerebellum on T2-weighted images. The ataxia of Fisher syndrome is not compatible with polyneuritis, but can be explained by a cerebellar lesion, as seen in this case.

Brain Stem↗
PubMed1997

An antibiotic, ascofuranone, specifically inhibits respiration and in vitro growth of long slender bloodstream forms of Trypanosoma brucei brucei.

Ascofuranone, a prenylphenol antibiotic isolated from a phytopathogenic fungus, Ascochyta visiae, strongly inhibited both glucose-dependent cellular respiration and glycerol-3-phosphate-dependent mitochondrial O2 consumption of long slender bloodstream forms of Trypanosoma brucei brucei. This inhibition was suggested to be due to inhibition of the mitochondrial electron-transport system, composed of glycerol-3-phosphate dehydrogenase (EC 1.1.99.5) and plant-like alternative oxidase. Ascofuranone noncompetitively inhibited the reduced coenzyme Q1-dependent O2 uptake of the mitochondria with respect to ubiquinol (Ki = 2.38 nM). Therefore, the susceptible site is deduced to be the ubiquinone redox machinery which links the two enzyme activities. Further, ascofuranone in combination with glycerol completely blocked energy production, and potently inhibited the in vitro growth of the parasite. Our findings suggest that ascofuranone might be a promising candidate for the chemotherapeutic agents of African trypanosomiasis.

Animals↗
PubMed1997

Pneumocephalus associated with fracture of thoracic spine: case report.

A 53-year-old man presented with pneumocephalus following a thoracic vertebral fracture. Computed tomography (CT) myelography revealed a leakage of contrast medium from the thecal sac in the vicinity of the vertebral fracture and was used to confirm the origin of a subarachnoid-pleural fistula.

Humans↗
PubMed1997

Postural and gait disturbance correlated with decreased frontal cerebral blood flow in Alzheimer disease.

In a group of 45 patients with Alzheimer disease (AD) and 15 control subjects, we studied the relationship between parameters showing postural and gait disturbance and regional cerebral blood flow (rCBF) measured with N-isopropyl-p-[123I]iodoam-phetamine single photon emission computed tomography at different clinical stages. Patients with AD with mild dementia exhibited only increased postural sway associated with a reduced mean value of rCBF in the cortex. At a moderate stage, the reduced mean values of rCBF in the cortex and in the frontal lobe were associated with increased postural sway and stride length variability and with decreased stride length. At a severe stage, reduced rCBF in the basal ganglia and in the frontal lobe additionally were associated with increased postural sway, double support time, and stride length variability, and with decreased walking speed and stride length. In multiple regression analysis, there was a high contribution by rCBF in the frontal lobe to account for postural and gait disturbance in AD. We propose that impaired frontal lobe circulation is an important factor causing postural and gait disturbance as AD progresses.

Aged↗
PubMed1997

Decreased cortical glucose metabolism correlates with hippocampal atrophy in Alzheimer's disease as shown by MRI and PET.

OBJECTIVE: To investigate the relation between atrophy of the hippocampus and parahippocampal gyrus (the % hippocampal area) and cerebral metabolic rate for glucose (CMRGlc) in Alzheimer's disease. METHODS: 13 patients with probable Alzheimer's disease by NINCDS-ADRDA criteria (six men; seven women, mean age 71 years, mini mental state 13.8 (SD 4.6)) and age matched controls were studied. T1 weighted MRI (0.5T) images were used for evaluation of the hippocampal area. With a digitiser system, a percentage of the hippocampal area to the brain (the % hippocampal area) was calculated. Eight patients received another T1 weighted MRI (1.5T) for further evaluation of the minimum thickness of the hippocampus. Regional CMRGlc (rCMRGlc) was measured using PET and the FDG technique. RESULTS: The hippocampal area in patients with Alzheimer's disease was significantly lower than that of controls (P < 0.01). All the cortical rCMRGlc values in patients with Alzheimer's disease were lower than those of controls (P < 0.01). A significant correlation (P < 0.05) was found between the % hippocampal area and rCMRGlc in the temporal lobe, temporoparieto-occipital (TPO) region, and frontal lobe in Alzheimer's disease. There was a significant correlation between minimal hippocampal thickness and ipsilateral TPO metabolism on both sides. CONCLUSION: The ipsilateral correlation between hippocampal atrophy and decreased TPO metabolism in Alzheimer's disease suggests a functional relation and the asymmetries show that Alzheimer's disease is an asymmetric disease in its early stages.

Aged↗
PubMed1997

Striatal dopamine metabolism correlated with frontotemporal glucose utilization in Alzheimer's disease: a double-tracer PET study.

We previously found that the rate of [l8F]6-fluoro-L-dopa (FDOPA) uptake into the striatum (the Ki value) in Alzheimer's disease (AD) correlated with cognitive function. Patients with wandering behavior had an increased level of D2 dopamine receptors. Decreased cerebral glucose utilization (CMRglc) in the parietal and temporo-parieto-occipital region is a well-known PET finding in AD. We investigated the relationship between the Ki value and regional CMRglc (rCMRglc) with reference to cognitive impairment and wandering behavior. We studied 10 AD patients with moderately severe dementia. Using PET and the FDOPA and [18F]-fluoro-deoxyglucose techniques, the Ki value and rCMRglc in 10 regions in each hemisphere were measured. The Ki value was found to correlate with mean cortical rCMRglc. The rCMRglc of the anterior frontal, inferior frontal, and temporal lobes correlated with the Ki value; the patients with wandering behavior had lower values. Multiple regression analysis showed that the Mini-Mental State Examination score was significantly explained by the Ki value, the rCMRglc of the temporal lobe, and the rCMRglc of the parietal lobe. There is probably a functional neural network between the striatum and the frontal and temporal lobes in AD. We consider this network important, not only in cognitive impairment but also in abnormal wandering behavior.

Aged↗
PubMed1997

[Evaluation of continuous blood pressure monitoring by arterial tonometry in the aged].

We compared tonometry systolic pressure with direct systolic pressure in 12 elderly patients (9 patients with sinus rhythm and 3 patients with atrial fibrillation) and 1 young adult patient undergoing surgical procedures in order to evaluate reliability of continuous blood pressure by arterial tonometry. In elderly patients when blood pressure fluctuated, the differences between tonometry systolic pressure and direct systolic pressure were larger compared with when blood pressure was stable. In the elderly with sinus rhythm, the correlation with stable blood pressure was 0.908; while that with fluctuating blood pressure was 0.838. In atrial fibrillation group, the differences between stable blood pressure and fluctuating blood pressure were still larger. The results indicate that it is difficult to use tonometry method as a reliable tool for blood pressure monitoring in geriatric anesthesia under circumstances of fluctuating blood pressure.

Adult↗
PubMed1996

An antibiotic, ascofuranone, specifically inhibits respiration and in vitro growth of long slender bloodstream forms of Trypanosoma brucei brucei.

Ascofuranone, a prenylphenol antibiotic isolated from a phytopathogenic fungus, Ascochyta visiae, strongly inhibited both glucose-dependent cellular respiration and glycerol-3-phosphate-dependent mitochondrial O2 consumption of long slender bloodstream forms of Trypanosoma brucei brucei. This inhibition was suggested to be due to inhibition of the mitochondriai electron-transport system, composed of glycerol-3-phosphate dehydrogenase (EC 1.1.99.5) and plant-like alternative oxidase. Ascofuranone noncompetitively inhibited the reduced coenzyme Q1-dependent O2 uptake of the mitochondria with respect to ubiquinol (Ki = 2.38 nM). Therefore, the susceptible site is deduced to be the ubiquinone redox machinery which links the two enzyme activities. Further, ascofuranone in combination with glycerol completely blocked energy production, and potently inhibited the in vitro growth of the parasite. Our findings suggest that ascofuranone might be a promising candidate for the chemotherapeutic agents of African trypanosomiasis.

Animals↗
PubMed1996

Thymic lymphoblastic lymphoma of committed natural killer cell precursor origin: a case report.

BACKGROUND: Recently, it was demonstrated that the human fetal thymocyte contains a bipotential progenitor capable of both T lymphocyte and natural killer (NK) cell differentiation. However, prior to this report a malignant neoplasm arising from these cells had not been documented. METHODS: A Japanese female age 38 years was examined by morphology of light and electron microscopy, immunohistochemistry, 3-color flow cytometry, cytotoxic assay, and Southern blotting. RESULTS: The patient presented with a mediastinal mass and pleural effusion. Leukemic progression was identified following chemotherapy and complete clinical remission. Immunophenotyping of lymphoma revealed CD45++, c-kit dim+, terminal deoxynucleotidyl transferase (TdT)-<+, CD38++, CD34+<++, CD33+<-, CD13dim+approximately+, HLA-DR+, CD7+, cytoplasmic CD3 (cCD3)+, surface CD3 (sCD3)-, CD2dim+, CD56+, CD16-, CD11b+, CD57-, CD1a-, CD5-, TCR alpha beta-, TCR gamma delta-, CD4-, CD8-, CD28-, CD10-, CD19-, CD20-, CD22-, surface immunoglobulins-, and CD14-. Functional NK activity of the lymphoma cells was extremely low. DNA analysis revealed no gene rearrangement in TCR beta, gamma, and delta or immunoglobulin heavy and light chain genes. CONCLUSIONS: Lymphoma cells of this case were derived from a distinct subtype of lymphocyte that originate from a thymic precursor committed to NK cell differentiation. This category is different from those of thymic T or precursor B cell pheno-/genotype.

Adult↗
PubMed1996

Cortical glucose metabolism in psychiatric wandering patients with vascular dementia.

The cerebral metabolic rate for glucose (CMRglc) in 18 patients with vascular dementia (VD) and 15 age-matched normal subjects was measured with positron emission tomography (PET) and the 18F-fluorodeoxyglucose technique. Nine of the 18 VD patients manifested abnormal wandering behavior with some psychiatric symptoms: they showed relatively spared CMRglc, which was higher than that of nonwandering patients, especially in the bilateral frontal lobes, left parietal lobe, left temporo-parieto-occipital region, left occipital lobe, and cerebellum. The results suggest that psychiatric wandering behavior of patients with VD could be correlated with partial sparing of CMRglc in the regions listed above.

Aged↗
PubMed1996

Relationship between falls and stride length variability in senile dementia of the Alzheimer type.

In this study, 97 patients with senile dementia of the Alzheimer type (SDAT) in a nursing home were followed over a period of 2 years, and the relationship between falls and gait function was examined. The findings indicated that the number of fallers was significantly higher in moderate-stage SDAT patients than in the mild-stage patients. In the moderate-stage SDAT patients, walking speed and stride length, measured as indices to evaluate gait function, were significantly lower, and the stride length variability was significantly higher than in mild-stage patients. When comparing the gait indices of fallers and non-fallers by the severity of dementia, a significant difference was observed only in stride length variability. The gait abnormality associated with advanced severity in dementia is believed to be a factor affecting falling. In particular, stride length variability appeared to be an effective predictor of falling.

Accidental Falls↗
PubMed1996

Magnetic resonance imaging of brain death.

Fifteen patients with clinical diagnosis of brain death were examined by magnetic resonance (MR) imaging. Aortography with intraarterial digital subtraction angiography (IADSA) was also performed in nine patients. MR imaging indications of the flow void phenomenon were evaluated in the cavernous portion of internal carotid artery (ICA) and the middle or anterior cerebral artery, and compared with the IADSA findings. The relative intensities of gray and white matters were also measured. MR imaging showed that flow voids were absent in the ICA in all eight patients in whom non-filling was confirmed by IADSA. In one patient, IADSA demonstrated intracranial flow despite the diagnosis of brain death and the flow void pattern was normal. Serial MR imaging showed disappearance or abnormality of flow voids after brain death in six patients and absence before brain death in one. Spotty flow voids became visible in the unilateral ICA of one case after brain death. Partial residual flow voids may be caused by to-and-fro blood movement which was demonstrated by transcranial Doppler sonography. The normal flow void pattern was seen in none of these patients, therefore absence of flow voids indicates cessation of intracranial blood flow. Proton density and T2-weighted MR images showed dissociated intensity changes between white and gray matters, which were thought to be characteristic of brain death. In conclusion, MR imaging can achieve non-invasive diagnosis of the non-filling phenomenon in patients with brain death.

Adult↗
PubMed1996

Expression of N-ras gene in gliomas.

Expression of N-ras gene was examined by northern blot analysis in two cases of astrocytoma (grade II), four cases of glioblastoma multiforme (six samples including two recurrent tumors), and normal brain tissues. Expression of N-ras gene was only found in the two recurrent glioblastoma multiforme samples. Southern blot analysis found no significant difference in copy numbers of N-ras gene in pre- and post-recurrence samples. The histological diagnosis of the two recurrent tumors was glioblastoma multiforme at both first recurrent presentation. However, the tumors had progressed during recurrence, because of worsened histological findings, such as increased cellularity, pleomorphism, and vascularity. These tumors recurred at very short intervals. Enhanced expression of N-ras gene by disorder of transcription may be a factor in the progression of glioblastoma multiforme.

Astrocytoma↗
PubMed1996

[Regional distribution of the muscarinic cholinergic receptor in the human brain studied with 11C-benztropine and PET using an anatomical standardization technique].

We measured regional distribution of the muscarinic cholinergic receptor in the normal human brain with 11C-benztropine (BZT) and positron emission tomography (PET) using an anatomical standardization technique. Seven normal volunteers who gave informed consents were involved in this study. Immediately after intravenous injection of 11C-BZT into the subjects, we started dynamic PET scanning and serial frequent arterial blood sampling. Analyses of plasma metabolites were also performed at selected time points and plasma time activity curves (TAC) of unmetabolized ligand were generated. From these PET and TAC data, we obtained Patlak plot slope calculation images. Using the HBA (human brain atlas) system, the Patlak plot slope calculation image of each subject was transformed into the shape of the standard brain. Mean and standard deviation (SD) calculation images were generated from those anatomically standardized images. On these mean and SD images, we placed regions of interest which were previously outlined on a MR image of the standard brain. From those data, we found the highest receptor distribution in the striatum and occipital cortex, as well as high distribution in the frontal, parietal, and temporal cortices, which were consistent with previous reports. These results suggested that anatomical standardization of PET receptor images with 11C-BZT will be useful for delineating the physiological or pathological alterations of the muscarinic cholinergic receptor in the human brain.

Adolescent↗
PubMed1996

[FLAIR images of patients with head injuries].

FLAIR (fluid-attenuated inversion recovery) images are MR images obtained with an inversion recovery sequence, which has a long inversion time (TI) and a long echo time (TE). We examined 29 cases (49 graphics) of cerebral contusion, 11 cases (22 graphics) of diffuse axonal injury (DAI) and 11 cases (11 graphics) of traumatic subarachnoid hemorrhage (t-SAH) with FLAIR sequence consisting of a repetitive time (TR) of 6500 msec, TI of 1700 msec and TE of 110 msec, and these graphics were compared with T2-weighted images by spin-echo sequence (TR 2500 msec, TE 90 msec) and computed tomographic (CT) scans. Some lesions of DAI were demonstrated more clearly with FLAIR images than with conventional T2-weighted images. Although contusion could be detected with FLAIR images as well as with conventional T2-weighted images, lesions adjacent to cerebral sulci were better delineated with FLAIR images. Because the cerebrospinal fluid signals in cerebral sulci were low-intensity, FLAIR images were useful in detecting lesions of the cerebral cortex adjacent to cerebral sulci. Although it has been reported that detection of SAH is difficult with standard T1- and T2-weighted images, the presence of t-SAH could be confirmed with FLAIR images as seen in CT scans.

Adult↗