Search PubMed⌕ Search

Biomedical subjects

H Fukuyama

Publications and source records attributed to H Fukuyama.

At least 181 records · Page 10Linked to original sources
PubMed1993

Prevalence of diabetes and impaired glucose tolerance in Funagata area, Japan.

OBJECTIVE: To determine the prevalence of diabetes mellitus and IGT in the Funagata area of Japan. RESEARCH DESIGN AND METHODS: The total eligible subjects was 1163, all were > or = 45 yr of age, and 52 were known diabetic patients. Data collected included body height, weight, and answers to medical questionnaires. A 75-g OGTT was done in the morning. WHO criteria were used to classify the current diabetes status of study participants. RESULTS: Of the 1111 scheduled for the OGTT, 868 took the test; the participation rate was 77.8%. The prevalence of diabetes was 10.5 and 12.9%, and the prevalence of IGT was 14.7 and 18.0% for men and women, respectively. The prevalence of undiagnosed diabetes (4.9%) was almost equal to that of previously diagnosed diabetes (4.5%). CONCLUSIONS: The prevalence of diabetes in the Funagata area was two to four times higher than that of previous reports in Japan, in which many investigators used a urinary glucose test as a preliminary test. This difference is attributed to the method of determining the prevalence of diabetes.

Age Factors↗
PubMed1993

[Immunohistochemical study on the distribution of CGRP-containing nerve fibers in the PCB poisoned rats with experimental periodontitis].

We have studied immunocytochemically the distribution of CGRP-containing nerve fibers in the PCB poisoned rats introducing experimental periodontitis. The results obtained were as follows. In the PCB poisoned rats, some specimens obtained from periodontitis-affected sites showed a slight increase in both the intensity of nerve staining and the nerve sprouting. However, no discernible difference in the occurrence and the distribution of nerves has been demonstrated between the PCB poisoned rats and clinically healthy rats. Further studies are needed to confirm the effects of PCBs on the initiation and progression of periodontitis.

Animals↗
PubMed1993

Functional mapping of flow and back-diffusion rate of N-isopropyl-p-iodoamphetamine in human brain.

Iodine-123-labeled N-isopropyl-p-iodoamphetamine (IMP) has been reported to be an excellent tracer for mapping cerebral blood flow with single-photon emission computed tomography (SPECT). Clinical interpretation of these SPECT images, however, requires further understanding of the kinetics of IMP in the human brain. In order to evaluate the kinetic behavior of IMP in normal and diseased areas, we measured flow and back-diffusion rates with serial dynamic SPECT scans following an intravenous bolus injection of IMP using a multi-detector SPECT scanner. Arterial input function was determined by octanol extracted radioactivity of serial arterial blood samples. Average values for influx rate (K1) and back-diffusion rate (k2) were 0.43 ml/g/min and 0.014 min-1 in the normal cerebral cortex, 0.43 and 0.013 in the basal ganglia, 0.28 and 0.012 in the white matter and 0.48 and 0.016 in the cerebellar hemisphere. The partition coefficient (K1/k2 ratio) was 32.4 ml/g in the cerebral cortex, 35.3 in the basal ganglia, 24.7 in the white matter and 30.4 in the cerebellum. The K1-to-k2 ratio in the infarcted and ischemic regions as well as in the tumor was smaller than that of the normal cortex. Accurate measurement of local cerebral blood flow (LCBF) based on the microsphere model was possible only on the early SPECT images, but a relative pattern of LCBF can be assessed with SPECT images obtained within 1 hr after injection except for tumors.

Adolescent↗
PubMed1992

Effect of brovincamine on cerebral circulation and metabolism in internal carotid artery occlusion examined by positron emission tomography.

We evaluated the effect of brovincamine on the circulatory and metabolic state in the brain ischemia with internal carotid artery occlusion accompanying the 'misery perfusion syndrome'. Cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO2) and oxygen extraction fraction (OEF) were measured by PET before and after intravenous loading of brovincamine. Brovincamine increased CBF and decreased OEF significantly on the occluded side of the hemisphere. CMRO2 did not show any remarkable changes upon brovincamine administration. It was concluded that brovincamine might be useful for increasing the hemodynamic reserve, but did not affect the metabolic state immediately after its administration.

Aged↗
PubMed1992

Significance of low perfusion with increased oxygen extraction fraction in a case of internal carotid artery stenosis.

BACKGROUND AND PURPOSE: Decreased cerebral blood flow with an increased oxygen extraction fraction, the so-called misery perfusion syndrome, suggests a vulnerability to reduction in cerebral perfusion pressure and a tendency to develop cerebral infarction. It is uncertain, however, whether the infarct would occur in the brain region specifically exhibiting this condition. CASE DESCRIPTION: We report the case of a patient with right intracranial internal carotid artery stenosis who presented with mild left hemiparesis resulting from a right frontal watershed infarct. Positron emission tomography 2 months after the stroke showed decreased cerebral blood flow with an increased oxygen extraction fraction in noninfarcted areas of the affected hemisphere. Maximal changes were detected in the watershed area between the middle cerebral artery and the posterior cerebral artery. Three months later, while on antiplatelet therapy, he suffered a new infarct in the right temporo-occipital watershed area that had shown the highest oxygen extraction fraction value on the first positron emission tomographic study. One month after the recurrence of stroke, a second study showed that low perfusion with increased oxygen extraction fraction persisted in the affected hemisphere to a lesser degree than in the first study. CONCLUSIONS: This observation suggests that the area of low perfusion exhibiting the highest oxygen extraction fraction has the highest risk for infarction. Increased oxygen extraction fraction may be an important factor in the development of hemodynamic infarction.

Brain↗
PubMed1992

Hemodynamic and metabolic changes in crossed cerebellar hypoperfusion.

BACKGROUND AND PURPOSE: The pathophysiology of crossed cerebellar diaschisis remains to be elucidated. The mechanism responsible appears to be deafferentation through the corticopontocerebellar tract, which terminates in the cerebellar gray matter. However, few studies have demonstrated the hemodynamic and metabolic changes in the cerebellar gray matter and pons in crossed cerebellar diaschisis. METHODS: Using positron emission tomography in 24 patients with unilateral supratentorial stroke, we evaluated regional blood flow, metabolic rate of oxygen, oxygen extraction fraction, and blood volume in the cerebellar cortex and pons. Sixteen patients with significant cerebellar blood flow asymmetry, defined as a percentage difference in blood flow beyond the upper 95% confidence limit defined in eight normal subjects, were selected as the group with crossed cerebellar hypoperfusion. RESULTS: In patients with crossed cerebellar hypoperfusion, the metabolic rate of oxygen was significantly decreased in the cerebellar cortex contralateral to the supratentorial stroke, compared with that in the ipsilateral cerebellar cortex; this decrease was less than the decrease in cerebellar blood flow. The degrees of cerebellar asymmetry in these two parameters were negatively correlated with the metabolic rate of oxygen in the pons. The oxygen extraction fraction was slightly, but significantly, increased. In contrast to the ischemic state, however, the cerebellar blood volume was decreased, with no difference in the ratio of cerebellar blood flow to blood volume. CONCLUSIONS: These findings support interruption of the corticopontocerebellar tract as the mechanism of crossed cerebellar hypoperfusion. Our results also suggest a mild elevation in the oxygen extraction fraction in this state, with a mechanism distinct from ischemia.

Adult↗
PubMed1992

Crossed cerebellar hypoperfusion in unilateral major cerebral artery occlusive disorders.

We evaluated regional blood flow and oxygen metabolism in the cerebral and cerebellar cortices of 15 patients with unilateral major cerebral artery occlusive disorders with PET. These patients showed a cortical blood flow asymmetry in middle cerebral artery distribution. Only subcortical abnormalities were detected on computed tomography. Nine patients showed crossed cerebellar hypoperfusion, a reduction in contralateral cerebellar blood flow, while six did not. No difference in the degree of cerebral blood flow asymmetry existed between the two patient groups. However, oxygen metabolism asymmetry was more pronounced and was more closely matched to blood flow asymmetry in patients with crossed cerebellar hypoperfusion. These findings suggest that a major cause of cerebral cortical blood flow reduction is reduced metabolic demand in patients with crossed cerebellar hypoperfusion. Crossed cerebellar hypoperfusion may have clinical significance as a reflection of the cerebral metabolic state on blood flow images.

Adult↗
PubMed1991

Enhanced expression of interleukin-6 in primary human renal cell carcinomas.

We have demonstrated interleukin-6 (IL-6) production by human renal carcinoma cells. The IL-6 gene expression was detected by Northern blot analysis in 22 of 43 primary renal cell carcinoma tissues and in five of seven renal cell carcinoma cell lines. Immunohistochemical analysis confirmed the expression of IL-6 by the tumor cells. Patients with a high-level expression of IL-6 had significantly greater incidences of lymph node metastasis and a larger increase in serum C-reactive protein than those without it. We have also probed for the presence of IL-6 receptor by Northern blot analysis; we detected this receptor in 11 of the 43 primary renal cell carcinoma tissues but in none of the seven renal cell carcinoma cell lines. However, by use of the complementary DNA-polymerase chain reaction, the IL-6 receptor transcript was detected in all specimens, including the seven cell lines. No expression of the interleukin-3 (IL-3) gene was identified in any of the 43 primary renal cell tumors. These data provide evidence that IL-6 and its receptor may play a role in promoting the transformation and/or proliferation of renal cell carcinomas as well as in teh development of symptoms.

Adult↗
PubMed1991

High-intensity area in the deep white matter indicating hemodynamic compromise in internal carotid artery occlusive disorders.

We used positron emission tomography and magnetic resonance imaging to evaluate 16 patients with transient ischemic attacks or minor strokes and unilateral internal carotid occlusive disease, five with stenosis, and 11 with occlusion. Cerebral blood flow, cerebral metabolic rate of oxygen, oxygen extraction fraction, cerebral blood volume, and T2-weighted magnetic resonance images obtained at 1.5-T were analyzed. Irrespective of vascular disease, patients with a confluent high-intensity area in the middle centrum semiovale had substantially decreased cerebral blood flow and ratio of cerebral blood flow to blood volume in the middle cerebral artery distribution of the cortex, with a substantially increased oxygen extraction fraction. We concluded that the confluent high-intensity area in the deep white matter region indicates hemodynamic compromise in the affected hemisphere in internal carotid artery occlusive disease.

Aged↗
PubMed1991

Coronal reconstruction images of glucose metabolism in Alzheimer's disease.

Coronal images of position emission tomography (PET) by 18F-labelled deoxyglucose reconstructed from interpolated scan in Alzheimer's disease clearly indicated suppression of glucose metabolism in the parietal lobe and lateral part of the temporal lobes, compared to normal controls. The medial part of the temporal lobes in Alzheimer's disease did show a mildly lower glucose metabolic rate than that in normal controls; therefore it is suggested that the parietal and lateral parts of the temporal lobes are primary affected regions in Alzheimer's disease, not the medial part of the temporal lobe, including the hippocampus.

Adult↗
PubMed1991

Ventricular wall motion and NE release in post-ischemic reperfused myocardium.

To clarify the relationship between post-ischemic myocardial dysfunction and local cardiac sympathetic nerve function, we measured regional myocardial length and norepinephrine (NE) release during sympathetic nerve stimulation in 32 mongrel dogs. Coronary occlusion was produced by balloon occluder for 15 min and reperfused for 60 min. Dogs were divided into 3 groups as follows; Group 1 (n = 14): Sympathetic nerve stimulation, Group 2 (n = 9): Pre-treatment with yohimbine hydrochloride (0.2 mg/kg) and sympathetic nerve stimulation, Group 3 (n = 9): Exogenous NE administration. Sympathetic nerve stimulation or NE infusion were performed before occlusion and after reperfusion. In group 1, the extent of the increase in systolic shortening during sympathetic nerve stimulation (delta - shortening) lowered at 5 min after reperfusion and augmented progressively. But, delta-shortening at an early reperfusion period did not reduce in group 2 and 3. NE release from the ischemic myocardium decreased in group 1 and did not recover for 60 min. When the cardiac sympathetic nerve was denervated with 90% phenol solution, NE release further decreased in group 1. On the other hand, NE release did not decrease in group 2. These results indicate that the response to sympathetic nerve stimulation decreased in post-ischemic reperfused myocardium and this was due to diminished NE release. It was considered that sympathetic nerve conduction was not completely impaired in post-ischemic myocardium and pre-synaptic alpha-2 receptor mediated negative feedback mechanism would play an important role in these diminished NE release.

Animals↗
PubMed1991

[Hemodynamics in the cerebral cortex and basal ganglia--observation on normal volunteers and patients with lacunes using PET].

We examined ten healthy volunteers using positron emission tomography (PET) in order to elucidate regional changes and correlations in the cerebral circulation and oxygen metabolism. We also studied eight lacunar stroke patients so as to disclose the influences of vascular risk factors and aging on the cerebral blood flow and metabolism. We can conclude from our result as follows: 1. Cerebral blood volume (CBV) was minimum in the basal ganglia and cerebral blood flow (CBF)/CBV ratio was higher than that of cerebral cortex in healthy volunteers; 2. CBF of gray matter in healthy volunteers correlated with CBV and cerebral metabolic rate of oxygen where oxygen extraction fraction inversely correlated with CBF, CBV, and CBF/CBV; and 3. the basal ganglia CBF/CBV ratio in lacunar stroke patients was lower than that of healthy volunteers. These findings suggested that the perfusion pressure in the basal ganglia was so high in the normal condition that the angionecrosis or occlusion in the perforating arteries would be induced, especially in the aged and hypertensive patients.

Adult↗