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Toshihiko Iwamoto

Publications and source records attributed to Toshihiko Iwamoto.

11 recordsLinked to original sources
PubMed2003

[Marked decrease of intracranial atherosclerosis in contrast with unchanged coronary artery stenosis in Japan].

We conducted comparative studies on intracranial atherosclerosis and coronary artery stenosis over the past 28 years. Two-year consecutive autopsy case studies from an urban geriatric hospital between 1974-1975 (Group I. 484 cases). 1986-1987 (Group II, 504 cases) and 2000-2001 (Group III, 273 cases) were employed. Atherosclerotic changes of the bilateral middle cerebral arteries and basilar artery were semiquantitatively evaluated as none (0), mild (1), moderate (2) and severe (3) and values of the 3 arteries were totalled to give a value of 0-9 which was taken as the intracranial atherosclerotic index (ICAI). The coronary stenotic index was calculated as previously reported (Sugiura et al 1969). ICAI and CSI were directly compared with each other, together with risk factors for each, including mean blood pressure (BP), serum level of total cholesterol (Tch) and the history of diabetes mellitus (DM+). Chronologically ICAI decreased dramatically but CSI did not change at all. There was continuous lowering of BP, elevation of Tch and increased incidence of DM+. There was a significant positive correlation in BP in relation to both ICAI and CSI (p < 0.01). DM+ vs. CSI (p < 0.01) and ICAI (p < 0.05), and Tch vs. CSI (p < 0.01) but not ICAI. Regression analysis highlighted age and BP as major risk factors for ICAI. Our study provides the first morphological confirmation of marked decrease of the intracranial atherosclerosis in the recent 28 years, in contrast with unchanged coronary stenosis in Japanese elderly subjects.

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PubMed2003

Changes in carotid atherosclerosis patterns detected by ultrasonography in Japanese elderly patients with aortic aneurysm.

To clarify current changes in the patterns of carotid atherosclerosis in Japan, carotid ultrasonographic findings in Japanese male patients with aortic aneurysm were compared between two groups examined in different periods. The first group was recruited from 42 consecutively examined patients in 1997, while the second group consisted of 40 consecutive patients from September, 2001 to January, 2002. Carotid lesions were analyzed by computer, and classified into three types based on the texture: echolucent, hyperechoic, and heterogeneous types. The mean age of the first group was 72 years, similar to that of the second group. In the first group, cigarette smoking was frequently noted, while the mean BMI was greater and IHD and CVD were frequent in the second group. Fifty carotid lesions were seen in each group. Severe stenosis and hypoechoic type lesions were more frequent in the second group than in the first group. These findings indicated that hypoechoic-type lesions, which are considered to be lipid deposition, hemorrhage, or loose fibrous tissue, and severe stenosis, were increased in the more recent group. This predicted that circulatory disturbance due to unstable atherosclerotic lesions may increase in the future among the elderly because carotid lesions reflect vascular change in other organs.

Age Factors↗
PubMed2002

Demonstration and distribution of tau-positive glial coiled body-like structures in white matter and white matter threads in early onset Alzheimer's disease.

The present report concerns the demonstration and distribution of tau-positive structures in the frontal and temporal white matter of five autopsy cases of early onset Alzheimer's disease (AD). The relationship between white matter lesions and tau positive structures was also investigated. Five early onset AD brains, which had not only unambiguous white matter lesions, but also no or rare atherosclerosis and minimal amyloid angiopathy, were examined. There were several tau-positive coiled body-like structures and many thread-like structures in the white matter, although previous reports showed only a few coiled bodies in the white matter in the AD brain. No relationship was found between the degree of each white matter lesion and number or distribution of tau-positive structures in the white matter. The results suggest that the AD brain has tau-positive structures in the white matter similar to some neurodegenarative brain diseases such as progressive supranuclear palsy, corticobasal degeneration, and dementia with grains. However, tau abnormalities may have fewer effects when they are located in white matter lesions in AD.

Age of Onset↗
PubMed2002

Increased blood-brain barrier permeability in white matter lesions of Binswanger's disease evaluated by contrast-enhanced MRI.

We investigated blood-brain barrier (BBB) permeability in white matter lesions of Binswanger's disease (BD) with contrast-enhanced MRI. Three subject groups were studied: 17 patients with BD and periventricular hyperintensities (PVH) on MRI, 10 patients with ischemic cerebrovascular events and with PVH but no dementia, and 14 age-matched control subjects without PVH. BBB permeability was quantified by calculation of T(1) change defined as [(T(1post) - T(1pre))/T(1pre)] x100, where T(1pre) and T(1post) represent the T(1) relaxation times before and after Gd-DTPA administration. T(1) change in PVH of BD patients significantly decreased in comparison with that observed in PVH of the nondemented patients and in normal white matter of the control subjects, but no significant T(1) change was observed between the PVH of the nondemented patients and normal white matter of the controls. There was a significant correlation between the Mini-Mental State Examination score and T(1) change for areas of PVH in BD. These results suggest that BBB permeability increases in areas of PVH in BD and that a BBB dysfunction is related to a progression of cognitive impairment.

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PubMed2002

Effects of novel phenoxazine compounds, 2-amino-4, 4a-dihydro-4alpha, 7-dimethyl-3H-phenoxazine-3-one and 3-amino-1, 4alpha-dihydro-4alpha, 8-dimethyl-2H-phenoxazine-2-one on proliferation of phytohemagglutinin- or anti-human IgM-activated human peripheral blood mononuclear cells.

We examined the in vitro effects of 2-amino-4, 4alpha-dihydro-4alpha, 7-dimethyl-3H-phenoxazine-3-one(Phx 1)and 3-amino-1, 4alpha-dihydro-4a, 8-dimethyl-2H-phenoxazine-2-one (Phx 2) on the proliferation of phytohemagglutinin (PHA)- or anti-human IgM-activated human peripheral blood mononuclear cells (PBMC). Phx 1 and Phx 2 inhibited the incorporation of 3H-thymidine of PHA-activated PBMC by as much as 75% and 40%, respectively, at a concentration of 40 microM. The inhibition was dependent on the dose of Phx 1 and Phx 2. These results strongly suggest that Phx 1 and Phx 2 inhibit proliferation of T cells, because PHA specifically activates the T cells among PBMC. On the other hand, when PBMC were activated by anti-human IgM, which specifically stimulates B cells, the incorporation of 3H-thymidine was rather increased in the presence of 15.8 microM Phx 1 or Phx 2. However, at a higher concentration of Phx 1 or Phx 2 (50 microM), the incorporation of 3H-thymidine was increased by Phx 1, but was inhibited by Phx 2. These results suggest different effects of Phx 1 and Phx 2 on proliferation of human T and B cells.

Animals↗
PubMed2002

Prognosis of the elderly with asymptomatic atherosclerotic plaques of the carotid arteries.

OBJECTIVE: To elucidate the prognosis of the elderly with neurologically asymptomatic atheromatous plaques of the carotid arteries. METHODS: A total of 228 subjects aged 60 years or older, examined by carotid ultrasonography and platelet aggregation test, were studied. They were divided into 3 groups based on plaque morphology: the no lesion group (n=110), the nodular plaque group (n=47), and the mural plaque group (n=71). Platelet aggregability was assessed as suppressed, normal, or accelerated. RESULTS: During the 4.0 years of mean follow-up period, 31 subjects died, and 16 of the deaths were due to vascular events such as cerebral infarction or ischemic heart disease. The annual mortality rate due to vascular events was 0.5% in the no lesion group, 1.4% in the nodular plaque group, and 4.1% in the mural plaque group, and Kaplan-Meier survival curve showed poor prognosis of the mural plaque group (logrank statistics: 12.8, Df=2, p=0.0017). According to the Cox proportional hazard model, a high hazard ratio (HR) was seen in the mural plaque group (5.3) and also the accelerated platelet aggregability group (4.0). CONCLUSION: These findings suggested that subjects with mural plaques and accelerated platelet aggregability, even when asymptomatic, have a poor prognosis due to vascular events. Antiplatelet therapy and exercise stress test for detecting coronary artery disease should be considered in these subjects.

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PubMed2002

[Evaluation of outcome based on platelet function in elderly patients with various diseases].

This study was conducted to clarify the relationship between the outcome of various diseases in elderly patients and platelet function. The outcome in 347 consecutive patients aged 60 or older, who were treated without antiplatelet drugs on registration, was retrospectively studied after platelet aggregability tests. The mean age was 77.5 years (161 men and 186 women). The grading curve (GC) type, as an index of platelet aggregability, was determined spectrophotometrically with an aggregometer and adenosine-5'-diphosphate as an agonist. They were classified into three groups according to GC type: Group I with a GC type of -2 or -1 (n = 40), group II with a GC type of 0 or +1 (n = 208), and group III with a GC type of +2 or +3 (n = 99). The mean follow-up period was 3.9 years. There were 3 deaths in group I, 33 in group II, and 30 in group III. Mean annual mortality rate was 2.1% in group I, 4.0% in group II, and 7.5% in group III. Among causes of death, vascular events was seen in 15 patients of group III, although the most common cause of death was pneumonia in the three groups. The annual mortality rates due to vascular events were 0.7% in group I, 0.6% in group II, and 4.2% in group III, indicating a significantly higher mortality rate in group III. Antiplatelet therapy was performed in approximately 15% of each group during their clinical course, and, when they were excluded for survival analyses, annual mortality rate was also higher in group III than in groups I and II. Cox proportional hazards models for vascular death yielded a hazard ratio of 2.3 and 2.2 in the increased GC type and diabetes, respectively. These findings indicated that elderly patients with accelerated aggregability had higher mortality rates due to vascular events. Therefore, accelerated aggregability in the elderly suggested not only the progress of arteriosclerosis, but indications of antiplatelet therapy to prevent vascular events.

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PubMed2002

[Carotid ultrasonographic and brain computerized tomographic findings in patients with vascular ocular syndromes].

To clarify the characteristics of cerebrovascular lesions in subtypes of vascular ocular syndrome, including amaurosis fugax(AF), retinal artery occlusion(RAO), and retinal vein occlusion(RVO), 93 patients with vascular ocular syndrome were studied by means of carotid ultrasonography(US) and brain computerized tomography(CT). The subjects comprised 21 patients with AF, 37 with RAO, and 35 with RVO who were sequentially given these diagnoses by the department of ophthalmology. On the basis of US findings, carotid lesions were defined as the presence of plaque or stenotic changes. CT findings were assessed for the presence and distribution of low-density areas(LDAs). Mean age was similar in each group, ranging from 64.5 to 67.4 years. The RAO group had high rates of men, hypertension, and smokers. US showed that the prevalence of carotid lesions ipsilateral to the affected eye was high in the RAO group and that severe stenosis and ulcerated plaque were present in 28.6% of the AF group and 45.9% of the RAO group. On CT examination, cerebral infarctions appeared as LDAs in about 10% of the patients in each group, and the incidence and distribution of LDAs were similar. Of 13 patients with cerebral infarction, only 2 were presumably due to carotid lesions; the others had a variety of causes. The discrepancy between US and CT findings was attributed to the small number of patients with cerebral infarction, since most patients had visual defects as an initial symptom. Our results suggest that extracranial carotid lesions, considered to be a major risk factor for stroke, should be carefully assessed in patients with AF or RAO to prevent further stroke.

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