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Biomedical subjects

K Meguro

Publications and source records attributed to K Meguro.

At least 145 records · Page 8Linked to original sources
PubMed1990

Magnetic resonance imaging of spinal cord injury without radiologic abnormality.

A 3-year-old girl with spinal cord injury without radiologic abnormality (SCIWORA) is reported. Magnetic resonance imaging (MRI) showed an abnormal intensity of the spinal cord at the level of C7 to Th1 in the acute stage and severe atrophic change in the chronic stage. This is the first report of SCIWORA with positive diagnostic imaging. The mechanism of SCIWORA is discussed based on the positive MRI findings.

Child, Preschool↗
PubMed1990

Cutaneous stimulation regulates blood flow in cerebral cortex in anesthetized rats.

The effect of noxious or innocuous mechanical stimulation of cutaneous areas (face, forelimb and paw, back, hindlimb and paw) on cerebral blood flow in cortex was examined with laser Doppler flowmetry in anesthetized rats. Pinching of the face, forepaw and hindpaw for 15 s produced significant increases of systemic blood pressure and of cortical blood flow, whereas pinching of the back or brushing of any cutaneous area produced no significant changes in either parameter. Following spinal transection at the first thoracic level, the blood pressure response to forepaw pinching was suppressed, whereas the increase in cortical blood flow still took place. Thus the results suggest that the increase in cortical blood flow following cutaneous noxious stimulation is, in part at least, independent of changes in blood pressure and of any concomitant vasodilatation.

Anesthesia↗
PubMed1990

Magnetic resonance imaging of a fat embolism of the brain: case report.

A 22-year-old man developed fat embolism syndrome. Although a computed tomographic (CT) scan of the brain showed nothing abnormal, a magnetic resonance imaging scan detected scattered spotty areas of low intensity on T1-weighted images and of high intensity on T2-weighted images. Magnetic resonance imaging is thought to be more sensitive than computed tomography in detecting cerebral fat embolism syndrome and correlates well with the clinical course.

Adult↗
PubMed1990

Disturbance in daily sleep/wake patterns in patients with cognitive impairment and decreased daily activity.

The sleep/wake patterns of 121 chronically ill, mentally and physically handicapped patients were visually monitored hourly for 14 consecutive days. Four types of sleep/wake patterns were found. In order to investigate how cognitive and physical functions correlated with sleep disorders, patients were classified based on a scale of mental function and the grading of daily activity. The percent of total sleep hours and the sleep rating, showing disturbances in sleep/wake pattern, were evaluated. We found a high degree of individuality in sleep/wake patterns. Sleep disturbance was associated with daily activity as well as with cognitive impairment. This monitoring system provides medical personnel with valuable information for clinical management.

Activities of Daily Living↗
PubMed1990

Stability of cerebral blood flow and oxygen metabolism during normal aging.

Cerebral blood flow and oxygen metabolism in aged normal subjects were measured with positron emission tomography and their relationship with brain atrophy was evaluated. Brain atrophy progressed in a linear fashion during aging while cerebral blood flow and oxygen metabolism were well preserved. The finding suggests that brain atrophy is an aging process less dependent on cerebral blood flow and metabolism over the course of normal aging.

Aged↗
PubMed1990

Studies on antidiabetic agents. IX. A new aldose reductase inhibitor, AD-5467, and related 1,4-benzoxazine and 1,4-benzothiazine derivatives: synthesis and biological activity.

N-Acetic acid derivatives (I) of 2-substituted 1,4-benzoxazines and benzothiazines were designed and synthesized for evaluation as new aldose reductase inhibitors. In general, 3-thioxo derivatives were more potent inhibitors of aldose reductase from human palcenta in vitro than the corresponding 3-oxo derivatives. While many compounds (I) were not very effective in inhibiting sorbitol accumulation in the rat sciatic nerve in vivo, the 3-thioxo compounds bearing an isopropyl group at the 2-position showed highly potent activity in the in vivo assay. Compound 46 (AD-5467) was selected from this series as a candidate for further development.

Aldehyde Reductase↗
PubMed1990

Characteristics of cerebral glucose utilization in dementia.

To make clear the characteristics of cerebral glucose uterization in dementia, PET studies with 18F-FDG were carried out. Taking the pattern of 18F-FDG uterization, dementia can be subdivided into two types. One type shows a simultaneous and symmetrical reduction glucose uterization in the posterior part of neocortex covering the temporal, parietal and occipital association cortices. This is referred to as type I. Although this type constitutes only about 1/5 of all dementia patients, it is considered the fundamental type of dementia. Aside from this, there is type wherein a simultaneous and symmetrical reduction in glucose uterization of the neocortex. This is type II. It constitutes about 4/5 of all dementia patients which is far more type I. There are no essential difference in the characteristics of cerebral glucose uterization in AD and MID. However, with regards the mean, AD is lower than MID. Various organic defect in neocortex do not correlate with the global reduction in glucose uterization in dementia patients. These results suggest that the reduction in glucose uterization in dementia may be functional disorder.

Aged↗
PubMed1990

Severe atrophy of amygdala and hippocampus in both Alzheimer's disease and multi-infarct dementia.

Alzheimer's disease and multi-infarct dementia are the two main diseases entirely different from each other producing almost the same abnormalities as dementia syndrome. With magnetic resonance imaging, severe atrophy of amygdala and hippocampus in both Alzheimer's disease and multi-infarct dementia was observed. There was no essential difference on the atrophic findings between Alzheimer's disease and multi-infarct dementia. This result therefore suggest that the quantitative measurement of amygdaloid and hippocampal atrophy predicts dementia.

Aged↗
PubMed1990

[Intraoperative evaluation of carotid endarterectomy with electromagnetic flowmetry and portable DSA].

In order to perform carotid endarterectomy more safely, we have evaluated, intraoperatively, the result of an operation with electromagnetic flowmeter and portable digital subtraction angiography (DSA). During surgery, flow of the exposed internal and common carotid artery was measured with an electromagnetic flowmeter, before and after endarterectomy. After the closure of the arteriotomy, portable DSA was carried out by injecting contrast medium from the common carotid artery. Our simple portable DSA system consists of a surgical X-ray television set, image processor (Sigma X) and still video-recorder. This system almost gives us a real-time presentation of a subtracted view of angiography. There were twenty patients including one patient with major stroke, 14 with minor stroke, three with transient ischemic attack, and two asymptomatic patients. Increase of the flow through the internal carotid artery was documented with an electromagnetic flow-meter in 13 of 20 patients following endarterectomy. Flow reduction was seen in two patients, one of whom was found to have an intimal flap from residual plaque visualized in the portable DSA. The plaque was removed by reopening the artery. Among twenty patients, intraoperative portable DSA showed an intimal flap in three patients and a step in four patients. Although the incidence of abnormal findings was high, degree of abnormality was not severe enough to reopen the artery except in one case. The purposes of carotid endarterectomy is two-fold. It is used for the removal of the plaques which can be a source of emboli, and also for the augmentation of flow in the narrowed segment of the artery.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Suprasellar ectopic pituitary adenoma: case report and review of the literature.

The occurrence of a totally suprasellar ectopic pituitary adenoma in a 71-year-old man is described. The tumor was attached to the pituitary stalk, extending upward toward the third ventricle. No intrasellar lesion was observed. Histological examination revealed a pituitary adenoma with large numbers of eosinophilic cells with moderate nuclear polymorphism and rare mitosis. Immunohistochemical staining revealed that the tumor cells were strongly positive for anti-adrenocorticotropic hormone antibody. A review of five previously reported intracranial ectopic pituitary adenomas revealed that two were silent corticotropic tumors and two occurred with Cushing's syndrome.

Adenoma↗
PubMed1990

[Essential thrombocythemia transformed to acute myeloblastic leukemia].

A 48-year-old woman was referred to Tohoku University Hospital in November 1981 because of leukocytosis pointed out in a group examination. At that time white blood cell count was 26.8 x 10(3)/microliters with no blasts, platelet count 268.0 x 10(4)/microliters and hemoglobin 11.4 g/dl. Bone marrow aspirates showed marked increase of megakaryocytes (15,900/microliters). Bone marrow chromosome analysis revealed 46, XX, -18, +mar without Ph1 chromosome, and DNA analysis showed no bcr rearrangement. She was diagnosed as having essential thrombocythemia and was treated with busulfan. On November 1986, she developed remarkable leukocytosis with leukemic blasts. White blood cells reached 153 x 10(3)/microliters with 33% blasts. Her blasts were positive for peroxidase staining, but negative for platelet peroxidase on electron microscopic study and platelet specific glycoproteins. A diagnosis of acute myeloblastic leukemia (M2) was made. The patient received various combination chemotherapy, which was ineffective, and she died due to pneumonia on June, 1989. In Japan, there has been reported only 8 cases of essential thrombocythemia transformed to acute leukemia. The clinical pictures of these 9 cases were discussed.

Cell Transformation, Neoplastic↗
PubMed1990

Effects of pioglitazone on glucose and lipid metabolism in normal and insulin resistant animals.

The antidiabetic effects of pioglitazone (5-[4-[2-(5-ethyl-2-pyridyl)ethoxy]benzyl]-2,4-thiazolidinedione, AD-4833, also known as U-72, 107E) were examined in normal, obese, and/or diabetic animals. When orally administered to genetically obese and diabetic yellow KK mice (2.4-24.5 mg/kg/d), and Zucker fatty rats (0.1-10 mg/kg/d) for 4 days, pioglitazone markedly decreased hyperglycemia, hyperlipidemia, hyperinsulinemia, and glucose intolerance characterized as insulin resistant states in these animals. Pioglitazone potentiated insulin-mediated glucose metabolism in the diaphragm and adipose tissues of yellow KK mice and enhanced the glycemic response to exogenous insulin in Zucker fatty rats. Four-day administration of pioglitazone (1 mg/kg/d) to aged and obese beagle dogs with moderate insulin resistance decreased plasma glucose and lipids in the fasting state, and postprandial rises in plasma triglyceride. Pioglitazone decreased plasma lipids but did not alter the plasma glucose level in young normal rats. Pioglitazone did not alter plasma glucose and lipid levels in streptozocin-diabetic rats. These results indicate that pioglitazone is effective on abnormal glucose and lipid metabolism associated with insulin resistance by enhancing insulin action on peripheral tissues. Therefore, pioglitazone is expected to be useful in treating obese non-insulin-dependent diabetes.

Adipose Tissue↗
PubMed1990

Studies on antidiabetic agents. Synthesis and hypoglycemic activity of 5-[4-(pyridylalkoxy)benzyl]-2,4-thiazolidinediones.

The synthesis of a series of 5-[4-(pyridylalkoxy)benzyl]-2, 4-thiazolidinediones is described. These compounds were evaluated for hypoglycemic and hypolipidemic activities in genetically obese and diabetic mice, yellow KK. 2-(2-Pyridyl)alkoxy derivatives were found to have much better hypoglycemic and hypolipidemic activities than 2-(3-pyridyl)- and 2-(4-pyridyl)alkoxy derivatives or even the previously reported compound, ciglitazone. The introduction of a hydroxyl group at the 2-position of the ethoxy chain potentiated the activities. Among the potent compounds, pioglitazone (AD-4833) was selected as a candidate compound.

Animals↗
PubMed1990

[Demonstration of a vascular lesion by intraoperative portable DSA in a case of intracerebral hematoma with impending herniation].

A nine year old boy with sudden onset of loss of consciousness was brought to the emergency room where he was in deep coma with bilateral decerebrated rigidity, and fixed dilated pupils. Computerized tomographic scan showed an intracerebral hematoma in the left temporal lobe associated with signs of uncal herniation. He was taken to the operating room immediately and craniotomy was started. After aspirating a small amount of hematoma through a burr hole, left carotid angiography was carried out by using a portable digital subtraction angiography (DSA) unit. The procedure took approximately ten minutes, and it showed arteriovenous malformation (AVM) supplied by a temporal branch of the middle cerebral artery. Using this angiogram as a guide, the intracerebral hematoma and the AVM were completely removed. The patient recovered well and returned to school after rehabilitation. This case illustrates a method of treatment for intracerebral hematoma with impending herniation. Although, in general, preoperative angiography is required before the operation of AVM, it could be argued that time spent for angiography may result in irreversible damage to the brain stem in the presence of uncal herniation. We chose to perform intraoperative portable DSA during evacuation of the hematoma instead of wasting time on preoperative angiography. With this method, we were not only able to remove the hematoma without delay, but were also able to extirpate the AVM safely. Whether or not our method can be used in general remains to be seen, and further experience is required.

Angiography, Digital Subtraction↗
PubMed1989

Effects of sevoflurane on autonomic nerve activities controlling cardiovascular functions in rats.

Effects of different inspiratory concentrations of sevoflurane (fluorometyl-1,1,1,3,3,3,-hexafluoro-2-propylether) on blood pressure, heart rate and efferent activities of cardiac sympathetic, cardiac parasympathetic and renal sympathetic nerves were examined using rats either under the resting condition or during noxious mechanical stimulation of a hindpaw. Under the resting condition, an increase in the inspiratory concentration of sevoflurane from 2.1% to 4.2% gradually caused a decrease in blood pressure and heart rate. With the increase in the sevoflurane concentration, cardiac sympathetic nerve activity decreased, whereas renal sympathetic nerve and cardiac parasympathetic nerve activities did not change significantly. When noxious mechanical stimulation was applied to a hind-paw by pinching, blood pressure and heart rate, renal sympathetic and cardiac sympathetic nerve activities all increased at the 2.1% concentration of sevoflurane. The responses of these parameters were attenuated at the 3.1% concentration of sevoflurane and almost disappeared at the 4.2% concentration. Cardiac parasympathetic nerve activity did not change significantly during the pinching stimulation throughout the 2.1-4.2% concentration increase.

Journal Article↗
PubMed1989

Synthesis and biological activities of optical isomers of 2-(4-diphenylmethyl-1-piperazinyl)ethyl methyl 1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-3,5-pyridinedicarboxylate (manidipine) dihydrochloride.

Enantiomeric (+)- and (-)-manidipine (1) dihydrochlorides were synthesized by the esterification of the optically active monocarboxylic acids (-)-6 and (+)-6, respectively. The absolute configurations, (S)-(+)-1 and (R)-(-)-1, were unambiguously determined by X-ray crystallographic analysis of (+)-7 derived from (-)-6. The (S)-(+)-1 was about 30 and 80 times as potent as the (R)-(-)-isomer in antihypertensive activity in spontaneously hypertensive rats (SHR), and in the radioligand binding assay using [3H]nitrendipine, respectively.

Animals↗
PubMed1989

[Barbiturate therapy in traumatic cerebral vascular disease: report of two cases].

We report two cases of traumatic cerebral vascular disease which were treated successfully with barbiturate. The first case sustained blunt trauma to the bilateral vertebral arteries, resulting in complete occlusion of both arteries. After ligation of the injured vertebral arteries, multiple cerebral infarction appeared. Cerebral angiography revealed dissection and stenosis of the bilateral internal carotid arteries. We treated this case with barbiturate (Thiamylal) in combination with administration of heparin. The second case sustained cerebral contusion and traumatic subarachnoidal hemorrhage as a result of a motor cycle accident. This patient deteriorated and cerebral angiography showed diffuse cerebral arterial vasospasms. When this was treated with induced hypertension, he developed recurrent subarachnoid hemorrhage. In order to protect the brain from ischemia without elevating blood pressure, we employed barbiturate therapy and the patient recovered without major neurological deficit. The condition of severe head injury with cerebral ischemia is complicated. Therefore it has been hard for neurosurgeons to cure the patient with this condition. But we treated it with barbiturate successfully. Barbiturate therapy in severe head injury with cerebral ischemia may decrease the mortality in that group of patients considered difficult to treat with the usual therapeutic modalities.

Adolescent↗