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Biomedical subjects

K Shima

Publications and source records attributed to K Shima.

At least 163 records · Page 9Linked to original sources
PubMed1996

Fatal subarachnoid hemorrhage from an inflammatory cavernous carotid artery aneurysm: failure of conservative treatment after early diagnosis--case report.

Inflammatory carotid artery aneurysm is a rare complication of acute paranasal sinusitis. A 50-year-old female presented with a ruptured giant carotid artery aneurysm secondary to infection of the sphenoid sinus and cavernous sinus. She had been healthy until 5 days before admission, when she developed orbital phlegmon and meningitis. She received antibiotic therapy for 10 days. Computed tomography (CT) of the brain 2 days after admission showed no abnormality. However, repeat CT on day 6 showed a round isodense mass in the suprasellar cistern suggesting a cerebral aneurysm. Twelve days after admission, she suffered a fatal subarachnoid hemorrhage. Cerebral angiography revealed a giant left cavernous carotid artery aneurysm with a very irregular shape. Autopsy found sphenoid sinusitis and osteomyelitis extending into the cavernous sinuses. Diagnosis of bacterial inflammatory aneurysms before rupture is very important. Appropriate surgical intervention should be considered if there is enlargement of the original aneurysm or appearance of a new aneurysm indicating a potentially dangerous situation.

Anti-Bacterial Agents↗
PubMed1996

Poor capacity for proliferation of pancreatic beta-cells in Otsuka-Long-Evans-Tokushima Fatty rat: a model of spontaneous NIDDM.

Otsuka-Long-Evans-Tokushima Fatty (OLETF) rat, a genetic model of spontaneous development of NIDDM, exhibits hyperglycemic obesity with hyperinsulinemia and insulin resistance similar to that in humans. It is still unclear whether a defect in the beta-cell proliferation per se is the primary pathogenetic event in OLETF rat. To determine whether it is, we used partially pancreatectomized rats as a model, with administration of phlorizin to control blood glucose level, to examine whether the capacity for proliferation of beta-cells during hyperglycemia or normoglycemia differs between OLETF and their diabetes-resistant counterparts, Long-Evans-Tokushima-Otsuka (LETO) rats. We also examined whether such a defect, if present, could be improved by nicotinamide. Male rats, 6 weeks of age, were allocated at random to two groups: 70% pancreatectomy (Px) and sham-pancreatectomy (sham). Each group was divided into four subgroups by date of killing after surgery: 3-day, 7-day, 28-day (treated with phlorizin, nicotinamide, or saline), and 91-day. A sustained hyperglycemia was evident in the Px OLETF rats after surgery, which was associated with insufficient proliferation of beta-cells, characterized by decrease in beta-cell labeling index in proportion to decrease in beta-cell mass and reduction in insulin content in the remnant pancreas. This defect was unaffected by restoration of normoglycemia induced by phlorizin injection. Administration of nicotinamide, however, ameliorated the sustained hyperglycemia by increasing beta-cell proliferation. These findings suggest that OLETF rats have poor capacity for proliferation of pancreatic beta-cells and that this change may be the critical pathogenetic event before the onset of overt diabetes.

Animals↗
PubMed1996

[Epidemiologic survey of pleural plaques among inhabitants of Matsubase exposed to asbestos].

A high prevalence of pleural plaques (41.5%, 148/357) was found during a mass screening for lung cancer in Matsubase town in 1988. The inhabitants of this town were carefully studied each year from 1988 to 1993. The vast majority (81.2%) of inhabitants over the age of 20 years underwent chest roentgenography at least once during this period. Pleural plaques were detected by CT in 938 subjects, which is 17.3% of those studied and 4.1% of the total population. A total of 89 had an occupational history of asbestos exposure, 64 (71.9%) of whom had pleural plaques. However, these subjects with occupational exposure accounted for only 6.8% of the 938 subjects, and therefore most of the pleural plaques seemed to have been caused by general environmental exposure. The incidence of plaques was greater in older subjects: among those in the seventh decade of life it was more than eight times higher than among those in the fourth decade of life. Anthophyllite was detected in the main asbestos mill. The concentrations of asbestos fibers in the air and water near the old asbestos mills and factories were not high. The death rates and the adjusted mortality rates due to lung cancer in Matsubase were lower than in surrounding towns and lower than in Kumamoto prefecture as a whole. These results indicate that there is now no environmental contamination by asbestos fibers in Matsubase town. No cases of malignant mesothelioma have been confirmed in this town during the past 17 years.

Adult↗
PubMed1996

Collagen types in healing alkali-burned corneal stroma in rabbits.

We evaluated the change in the type of collagen found during healing in the alkali-burned corneal stroma of rabbits. We estimated the relative proportions of alpha chains in pepsin-solubilized collagen, using sodium dodecylsulfate polyacrylamide gel electrophoresis. Bands of alpha 1(I), alpha 2(I), alpha 1(V), and alpha 1(III) chains stained with Coomassie Blue were separated. The alpha 1(III) and alpha 1(V) chains showed a transient proportional increase in healing corneal stroma in the area exposed to alkali. No significant alterations in collagen alpha chains were detected in peripheral corneal stroma that had not been directly exposed to alkali. Our results suggest that the keratocytes which repopulate the alkali-injured corneal stroma early in healing synthesize a higher proportion of collagen types III and V than type I, and then switch to synthesizing predominantly type I collagen as stromal healing progresses. Collagen types III and V thus appear to be of primary importance in the healing of the corneal stroma.

Animals↗
PubMed1995

Dexamethasone regulates obese expression in isolated rat adipocytes.

An obese (ob) gene product, expressed specifically in adipose tissues, regulates energy balance. Here we report adipocytes in adipose tissue actually express ob mRNA and that a synthetic glucocorticoid (dexamethasone) regulates expression of the ob gene. Addition of 100 nM dexamethasone to isolated rat adipocytes rapidly induced a 4-8 fold increase in ob mRNA. This increase in ob mRNA level was apparent within 1 h, and reached a maximum at about 7 h after stimulation. The dexamethasone-stimulated increase of ob mRNA was only partially blocked by protein synthesis inhibitors cycloheximide (20 micrograms/ml) or anisomycin (200 microM). This suggests that new protein synthesis is not necessarily required for the observed dexamethasone-stimulated increase in ob mRNA.

1-Methyl-3-isobutylxanthine↗
PubMed1995

Spatial distribution of thalamic projections to the supplementary motor area and the primary motor cortex: a retrograde multiple labeling study in the macaque monkey.

The exact knowledge on spatial organization of information sources from the thalamus to the supplementary motor area (SMA) and to the primary motor cortex (MI) has not been established. We investigated the distribution of thalamocortical neurons projecting to forelimb representations of the SMA and the MI using a multiple retrograde labeling technique in the monkey. The forelimb area of the SMA, and the distal and proximal forelimb areas of the MI were identified by electrophysiological techniques of intracortical microstimulation and single neuron recording. Injections were made into these three representations with three different dyes in the same animal (horseradish peroxidase conjugated to wheat germ agglutinin, diamidino yellow, and fast blue), and the thalamic neurons were retrogradely labeled. Injections into the SMA densely labeled thalamic neurons in nuclei ventralis lateralis pars oralis (VLo), ventralis lateralis pars medialis (VLm) and ventralis lateralis pars caudalis (VLc), but not in nucleus ventralis posterior lateralis pars oralis (VPLo). Injections into the MI labeled thalamic neurons primarily in VLo, VLc, and VPLo. We found that the distribution of projection neurons to the three areas was largely separate in the thalamus. However, in the middle part of VLo, and in a limited portion of VLc, thalamic neurons projecting to the SMA partially overlapped with those to the distal forelimb area of the MI. They overlapped little with those to the proximal forelimb area of the MI. We noted no overlap between the distributions of thalamic projection neurons to the distal and proximal forelimb areas of the MI. These findings suggest that the SMA and MI receive separate information from the thalamus, while sharing minor sources of common inputs.

Animals↗
PubMed1995

Cloning of rat obese cDNA and its expression in obese rats.

The mouse obese gene product, expressed specifically in adipose tissue, regulates energy balance in mice. Mutation of the obese gene results in marked obesity and type II diabetes as part of a syndrome that resembles morbid obesity in humans. Here we report the cloning and sequencing of rat obese cDNA. Neither alterations of nucleotide sequence in the coding region nor changes of the gene structure were found in two rat strains with obesity, Zucker (fa/fa) and Otsuka Long Evans Tokushima Fatty. The expression level of obese mRNA in adipose tissue of Zucker (fa/fa) rat was found to be about 4 times that in lean littermates, suggesting some mutation or abnormal expression of the receptor for the obese product in obese rats of this strain.

Animals↗
PubMed1995

Stable prostacyclin improves postischaemic microcirculatory changes in hypertensive rats.

The prostacyclin analogue TTC-909 is incorporated in lipid microspheres and is chemically very stable. We examined the efficacy of TTC-909 on cerebral microcirculation following focal cerebral ischaemia. Focal cerebral ischaemia was produced by the occlusion of the distal middle cerebral artery in stroke-prone spontaneously hypertensive rats. Intravenous administration of TTC-909 (100 ng/kg/day) or vehicle was started 30 minutes after the occlusion and repeated for 7 days. On day 7, cerebral blood flow and blood-brain barrier permeability were measured autoradiographically. Brain oedema was estimated by the gravimetric method. The size of the infarction was calculated from area measurements on serial histologic sections. Treatment with TTC-909 resulted in significant improvement in regional blood flow in the ischaemic rim (p < 0.01) and the surrounding area (p < 0.05). With TTC-909 treatment, the increased permeability was significantly reduced in the ischaemic centre (p < 0.01) and rim (p < 0.05). A decrease in specific gravity in the ischaemic region and the remote non-ischaemic regions was prevented by the treatment (p < 0.01). We assumed that the efficacy of TTC-909 maintains the blood supply in the ischaemic area, improves disruption of the blood-brain barrier and prevents development of ischaemic oedema.

Animals↗
PubMed1995

Which is the primary etiologic event in Otsuka Long-Evans Tokushima Fatty rats, a model of spontaneous non-insulin-dependent diabetes mellitus, insulin resistance, or impaired insulin secretion?

To identify the primary disorder causing diabetes mellitus in a model rat (Otsuka Long-Evans Tokushima Fatty [OLETF]) with non-insulin-dependent diabetes mellitus (NIDDM), we studied the temporal relationship between insulin resistance and impairment of pancreatic beta-cell function. Groups of 28 male OLETF rats and male nondiabetic control Long-Evans Tokushima Otsuka (LETO) rats were given an intravenous (i.v.) glucose and glucagon tolerance test (IVGTT) and hyperinsulinemic euglycemic clamp tests at 10, 16, 24, and 40 weeks of age. After the euglycemic clamp test, abdominal fat was measured and the pancreas was examined histologically. At 16 weeks of age, insulin-mediated whole-body glucose uptake as measured by the hyperinsulinemic euglycemic clamp technique was significantly reduced in OLETF rats (glucose infusion rat [GIR], 40.9 +/- 4.2 mumol/kg.min) as compared with LETO rats (78.4 +/- 6.9). On the other hand, plasma insulin responses to glucose and glucagon in OLETF rats were higher than those in LETO rats at 16 and 24 weeks of age, but clearly decreased at 40 weeks of age (sigma immunoreactive insulin [IRI] to glucagon, 8.81 +/- 1.81 v 27.32 +/- 4.59 nmol.min in OLETF and LETO rats, respectively, P < .01). Abdominal fat deposition was significantly greater in OLETF rats than in LETO rats at all ages tested except 10 weeks. Pancreatic islets of OLETF rats became enlarged and fibrotic. These results demonstrated that insulin resistance preceded impairment of pancreatic beta-cell function in OLETF rats, and that insulin resistance seemed closely related to fat deposition in the abdominal cavity.

Age Factors↗
PubMed1995

Is caloric restriction effective in preventing diabetes mellitus in the Otsuka Long Evans Tokushima fatty rat, a model of spontaneous non-insulin-dependent diabetes mellitus?

Studies were made on the effectiveness of caloric restriction in preventing the development of diabetes mellitus in a model rat (Otsuka-Long-Evans-Tokushima Fatty; OLETF) with non-insulin-dependent diabetes mellitus (NIDDM). Groups of 8 male OLETF rats aged 5 weeks were supplied with rat chow ad libitum (100% group) and 85% and 70% of the amount of food consumed by the 100% group (85% and 70% groups, respectively). The average weights of the 100%, 85% and 70% groups were 617, 536 and 450 g at 19 weeks of age and their abdominal fat deposits were 50, 38 and 21 g, respectively, at 22 weeks of age when they were killed. At 20 weeks of age, the cumulative incidences of diabetes mellitus in the 100%, 85% and 70% groups were 67%, 13% and zero, respectively. The plasma immunoreactive insulin (IRI) levels 60 and 120 min after oral glucose administration were significantly lower in the 70% group than in the other groups. In vivo insulin-stimulated glucose uptake measured by a euglycemic clamp technique, was significantly higher in the 70% group than in the 100% group. There was no significant difference in the glucose transporter 4 protein levels of skeletal muscles in the three groups, but the highest ratio of glucose transporter 4 in the plasma membrane to that in intracellular membranes was observed in the 70% group. Morphological studies on the pancreas of rats in the 100% group showed enlarged multilobulated fibrotic islets, whereas sections of islets of rats in the other groups appeared normal, though slightly enlarged. These results demonstrate that caloric restriction is effective in preventing NIDDM in diabetes-prone rats, probably due to increased insulin sensitivity.

Aging↗
PubMed1995

Effects of obesity and inheritance on the development of non-insulin-dependent diabetes mellitus in Otsuka-Long-Evans-Tokushima fatty rats.

We studied whether obesity or inheritance was the more important factor in the development of non-insulin-dependent diabetes mellitus (NIDDM) using female Otsuka-Long-Evans-Tokushima Fatty rats (OLETF) possessing one of the diabetic genes, ODB-1, and male Long-Evans-Tokushima-Otsuka rats (LETO) possessing no ODB-1, neither of which were diabetic when bred normally. Diabetes-resistant male LETO rats and female OLETF rats (4 weeks old) were assigned to three groups of 6 rats each, respectively; two groups in which obesity was induced by high calorie 'cafeteria' diet (D), or ventromedial hypothalamus lesions (V) with normal chow diet and a control group fed on normal chow (C). Six male OLETF rats were used as NIDDM positive controls. The mean daily energy intakes of obese male LETO and female OLETF rats were higher than those of the respective C groups. At 27 weeks of age, the average body weights of the obese LETO and female OLETF rats were significantly higher than those of the respective C groups and similar to that of the male OLETF group. Abdominal fat deposits of the obese groups were significantly higher than those of the respective C groups. At 28 weeks of age, the cumulative incidence of diabetes mellitus in obese LETO rats was 0% in group D and 17% in group V, while that of obese female OLETF rats in groups D and V were 100%. At 29 weeks of age, the plasma immunoreactive insulin (IRI) responses to glucose in obese female OLETF rats, groups D and V, were higher than that in group C. In obese LETO rats, insulin-stimulated glucose disposal in vivo was similar to that in group C, but in obese female OLETF rats, it was reduced to 41% in group D and 37% in group V of that in group C. Sections of islets of the pancreas of obese LETO rats appeared histologically normal, whereas those of obese female OLETF rats showed enlarged multilobulated fibrotic islets. These results demonstrate that obesity is necessary, but not sufficient alone for the development of NIDDM in these rat models.

Analysis of Variance↗
PubMed1995

IDF Member Associations' activities presented in the 15th IDF Congress Exhibition.

IDF Member Associations' activities were presented in the 15th IDF Congress Exhibition held at Port Island, Kobe, Japan from November 7 to November 11, 1994. The purpose of the exhibition was to inform members of the progress on patient education, guidance of diet and exercise treatment, the compliance situation on self-monitoring of blood glucose, self-injection of insulin, etc., in each association. A total of 31 associations including 17 from outside Japan and 14 from Japan participated in this exhibition. An exhibition theme was not designated to foreign associations. However, in order to avoid a similar content of exhibitions from the Japanese associations, a specific theme was assigned to each association. From these exhibitions we can comprehend the present status of the activities of all the diabetic associations in the world. Especially, an enthusiasm for patient and co-medical staff education in each association was clearly recognized. The total number of visitors including the commercial exhibition during the Congress reached about 17000 people.

Diabetes Mellitus↗
PubMed1995

Cerebral blood flow and glucose metabolism of the ischemic rim in spontaneously hypertensive stroke-prone rats with occlusion of the middle cerebral artery.

To determine acute postischemic metabolic changes of the ischemic rim under conditions of poor collateral circulation, we examined cerebral blood flow and glucose metabolism in the area of the brain around the ischemic tissue in 36 male spontaneously hypertensive stroke-prone rats (SHRSP) in the acute stage of focal ischemia. The right middle cerebral artery (MCA) was occluded dorsal to the rhinal fissure. Four hours after occlusion, local cerebral blood flow (LCBF), glucose content (LCGC), and glucose utilization (LCGU) were measured by quantitative autoradiographic techniques. The lumped constant was determined from the corresponding LCGC. LCBF showed a widespread and marked decrease in the cortex surrounding the ischemic core, in the thalamus, and in the medial portion of the striatum in the MCA-occluded hemisphere, while the lateral segment of the striatum showed an increase of 36%, compared with findings on the contralateral side. LCGC showed little regional variation, but there was an increase of 38% in the zone bordering the ischemic area. LCGU at the cortex surrounding the ischemic core and in the external capsule showed an increase of 55%. The cortex surrounding the ischemic core, the thalamus, and the lateral segment of the striatum in the MCA-occluded hemisphere showed significant decreases in LCGU. It has been speculated that a high accumulation of glucose reflects a demand for glucose for anaerobic glycolysis in the border areas and that such a demand is probably greater in cases of impaired oxygen delivery due to the presence of microcirculatory disturbances in the MCA-occluded SHRSP.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗