PubMed Health⌕ Search

Biomedical subjects

T Iwami

Publications and source records attributed to T Iwami.

At least 19 recordsLinked to original sources
PubMed2001

Stereopsis-processing regions in the human parieto-occipital cortex.

We performed fMRI on the human parieto-occipital cortex in order to identify the neural processing regions of stereopsis. Visual stimulation for stereopsis was performed with a random-dot stereogram displayed in the image guides of a new binocular visual stimulation device that we developed. Interestingly, regions from the dorsal portion of the occipital lobe to the superior parietal lobule were activated by binocular disparity, while the inferior parietal lobule was not activated. Moreover, these regions were shown as dominant in the right hemisphere. Functional brain mapping revealed that the processing regions of stereopsis were dorsally located in parieto-occipital cortex, and that the superior parietal lobule is an important region for neural processing of human stereopsis.

Adult↗
PubMed2001

Effect of low-intensity warfarin therapy on left atrial thrombus resolution in patients with nonvalvular atrial fibrillation: a transesophageal echocardiographic study.

The presence of left atrial thrombus (LAT) is associated with an increased risk of embolic stroke. However, it has yet to be established definitively whether low-intensity warfarin therapy (INR: 1.5-2.0) can prevent LAT formation in patients with nonvalvular atrial fibrillation (NVAF). The present study analyzed the clinical and transesophageal echocardiography (TEE) features of 123 such patients to identify risk factors for LAT formation and the efficacy of prophylactic low-intensity warfarin therapy. Left atrial thrombi were found in 35 patients (28%) in whom systemic hypertension (49% vs 23%; p<0.01) and ischemic heart disease (17% vs 3%; p<0.01) were more frequent. Left ventricular ejection fraction (54+/-14% vs 60+/-11%; p<0.05), left ventricular end-diastolic dimension (51+/-7 mm vs 48+/-5 mm; p<0.05), spontaneous echo contrast (2.2+/-0.7 vs 1.4+/-0.9; p<0.01), left atrial diameter (50+/-6 mm vs 43+/-7 mm; p<0.01), left atrial appendage blood velocity (22.3+/-8.7 cm/s vs 37.2+/-21.5 cm/s; p<0.01) and the incidence of left ventricular hypertrophy (37% vs 15%; p<0.01) were also significantly different between the groups. Fourteen patients received continuous warfarin therapy (target INR: 1.5-2.0) and on the follow-up TEE study the left atrial thrombus resolved in 10 (71%). There were no thromboembolic events or major hemorrhagic complications in these patients, so it was concluded that low-intensity warfarin therapy is efficacious in treating LAT formation in patients with NVAF.

Adult↗
PubMed2001

Evaluation of left atrial function by the functional volume change curve derived from Doppler flow spectra.

The objective of this study was to clarify the left atrial (LA) reservoir and booster pump function in patients with left ventricular (LV) diastolic dysfunction. To determine LA reservoir and booster pump function, a new algorithm to determine LA functional volume change curve (FVC) was developed from Doppler flow spectra of pulmonary venous flow and LV inflow by transthoracic echocardiography in 110 patients. Patients were classified into normal (N), and abnormal (AB) and pseudonormal (PN) groups on the basis of their Doppler flow patterns. From the indices of FVC, atrial reservoir volume (ARV), passive emptying volume (PEV) and active emptying volume (AEV) were obtained. ARV/stroke volume (SV) was increased in the AB group, but decreased in the PN group compared with N (N, 0.61+/-0.09; AB, 0.73+/-0.10; PN, 0.52+/-0.13, p<0.05). PEV/SV was significantly decreased in AB, but increased in PN compared with N (N, 0.27+/-0.07; AB, 0.19+/-0.07; PN, 0.31+/-0.18, p<0.05). AEV/SV was significantly increased in AB, but decreased in PN compared with N (N, 0.41+/-0.08; AB, 0.56+/-0.10; PN, 0.26+/-0.19, p<0.05). Thus, in patients with an abnormal relaxation pattern, the LA reservoir and booster pump function are augmented, but in patients with a pseudonormal pattern, both LA reservoir and booster pump function are deteriorated, suggesting a vulnerability to pulmonary congestion.

Adult↗
PubMed2000

Eosinophil counts and plasma fibrinogen in patients with vasospastic angina pectoris.

Epidemiologic studies have suggested a relation between white blood cell (WBC) counts and the incidence of coronary heart disease. However, the relation between vasospastic angina pectoris (VAP) and WBC counts remains to be elucidated. To clarify the relation between differential and WBC counts in VAP, we compared the hematologic values, blood chemical values, plasma fibrinogen levels, C-reactive protein levels, and coronary risk factors in patients with spontaneous attacks of VAP (n = 39) with those in patients with stable effort angina pectoris (EAP, n = 35) and in control subjects (n = 19). Patients with VAP were further divided into mild VAP (n = 22) and severe VAP groups (n = 17). There were no differences in the coronary risk factors, body temperature, total WBC counts, and C-reactive protein levels among the control, EAP, mild VAP, and severe VAP groups, except that the high-density lipoprotein cholesterol in the EAP group was significantly lower than that in the control group (p <0.01). In contrast, the eosinophil counts were significantly higher in the severe VAP group than in the other 3 groups (p <0.01). Plasma fibrinogen levels were also significantly higher in the severe VAP group than in the other 3 groups (p <0.05). The follow-up study for differential and WBC counts in patients with VAP (n = 23) demonstrated that, after medical therapy, the eosinophil counts were significantly decreased to the some level as those in the control group (p <0.0001). Thus, the eosinophil counts and plasma fibrinogen levels could predict the severity of VAP. Furthermore, a follow-up study in patients with VAP suggests that coronary vasospasm could result in an increase in eosinophil counts.

Angina Pectoris↗
PubMed1999

[Diagnosis of magnetic resonance imaging (MRI) for blowout fracture--three advantages of MRI].

INTRODUCTION: Magnetic resonance imaging (MRI) gives a much more detailed picture of the soft tissue than computerized tomography (CT). In blowout fracture cases, it is very easy to observe the incarcerated orbital tissue. SUBJECTS: We performed MRI in 19 blowout fracture cases. RESULTS: After evaluating the images, we found three advantages of MRI. The first is that even small herniation of the orbital contents can easily be detected because the orbital fatty tissue contrasts well around the other tissues in MRI. The second is that the incarcerated tissues can be clearly differentiated because a clear contrast between the orbital fatty tissue and the extraocular muscle can be seen in MRI. The third is that the running images of the incarcerated muscle belly can be observed because any necessary directional slies can be taken in MRI. CONCLUSION: These advantages are very important in the diagnosis of blowout fractures. MRI should be employed in blowout fracture cases in addition to CT.

Adolescent↗
PubMed1998

Importance of left anterior descending coronary artery curvature in determining cross-sectional plaque distribution assessed by intravascular ultrasound.

We assessed the relation between the circumferential distribution of coronary atherosclerotic plaques and the structure of the epicardial coronary arteries in patients with coronary artery disease using intravascular ultrasound in vivo. Coronary atherosclerosis preferentially formed at the inner arc of the curved coronary vessels, and greater vessel curvatures were associated with greater distributions of atherosclerotic lesions along the inner coronary artery wall.

Adult↗
PubMed1998

Pre-clinical Cushing's syndrome with body weight loss and normal circadian rhythm of blood pressure.

A 68-year-old woman was referred for evaluation of an incidentally discovered left adrenal mass. Her chief complaint was body weight loss. She showed no symptoms or signs suggestive of Cushing's syndrome. The circadian rhythm of blood pressure was also normal. Hormonal assessment revealed an abnormal diurnal variation in serum cortisol levels, suppressed baseline plasma adrenocorticotrophic hormone, and nonsuppression of serum and urinary cortisol with the dexamethasone suppression test. Adrenal scintigraphy with (131)I-6-beta-iodomethyl-norcholesterol showed uptake on the left adrenal and inhibition of the contralateral adrenal gland. She was diagnosed as pre-clinical Cushing's syndrome. Due to the lack of clinical symptoms and the risks of surgery, we emphasize the importance of careful assessment of the cortisol metabolism and scintigraphic scanning under dexamethasone suppression to avoid post-surgical Addisonian crisis.

Adrenal Gland Neoplasms↗
PubMed1996

Limitations of intravascular ultrasound for the evaluation of coronary luminal area--comparison with quantitative angiography.

To evaluate the accuracy of intravascular ultrasound (IVUS) for the measurement of coronary luminal area, we compared IVUS with quantitative coronary angiography (QCA). We studied 46 segments in 21 patients who underwent coronary intervention. In each lesion, coronary luminal areas were evaluated by both IVUS and QCA. To quantitate the differences between the two modalities, we calculated a difference index (magnitude of intraluminal area by IVUS -intraluminal area by QCA/intraluminal area by IVUS). We also calculated an eccentricity index (the thinnest thickness of plaque divided by the width of the opposite plaque) using IVUS. All samples were classified into 2 groups according to the lumen diameter by QCA. In Group I (lumen diameter > or = 3.0 mm), we found a close correlation between the intraluminal areas obtained by the two modalities (r = 0.95, p < 0.001). In Group II (lumen diameter < 3.0 mm), we found a lower correlation between the intraluminal areas obtained by the two techniques (r = 0.61, p < 0.005), and the intraluminal area by IVUS was significantly larger than that from QCA (p < 0.001). Furthermore, there was an inverse correlation between the eccentricity index and the difference index in Group II (r = 0.83, p < 0.001). These findings indicate that the differences between ultrasonic and angiographic measurements the coronary luminal area were greater in coronary arteries with a narrow lumen due to plaque eccentricity.

Aged↗
PubMed1996

A case of acute eosinophilic pneumonia. Evidence for hypersensitivity-like pulmonary reaction.

We examined an 86-year-old man with acute respiratory failure. A chest roentgenogram showed diffuse reticular shadows. Transbronchial biopsy revealed thickening of the alveolar septa accompanied by moderate eosinophil infiltration. After admission to the hospital, the patient's symptoms immediately improved without any medication. Clinical course and pathologic findings suggested acute eosinophilic pneumonia caused by a hypersensitivity reaction.

Acute Disease↗
PubMed1996

Iodine-123-MIBG imaging in pheochromocytoma with cardiomyopathy and pulmonary edema.

We encountered a patient with pheochromocytoma associated with a catecholamine-induced cardiomyopathy that developed recurrently bilateral and unilateral pulmonary edema. The diagnosis of pheochromocytoma was made by elevated plasma catecholamine levels and the intense tumor [123I]MIBG uptake and was confirmed at the time of surgery. The patient showed reduced myocardial [123I]MIBG uptake with left ventricular dysfunction, and endomyocardial biopsy findings were consistent with the diagnosis of catecholamine-induced cardiomyopathy. After tumor resection, plasma levels of catecholamine were normalized, and pulmonary edema never recurred, although cardiac dysfunction did not show an improvement on echocardiography. Myocardial and lung [123I]MIBG uptake increased when compared to uptake levels on preoperative scans, but myocardial uptake was still below normal. These findings indicated that over-secreted catecholamines influenced both the heart and lungs. Pheochromocytoma can induce cardiac and lung injuries, and [123I]MIBG scanning may contribute not only to tumor characterization but also to assessing and monitoring the influence of catecholamines on the heart and lungs.

3-Iodobenzylguanidine↗
PubMed1993

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

We determined whether exercise training is effective in preventing the development of diabetes mellitus in a model rat (Otsuka-Long-Evans-Tokushima Fatty [OLETF]) with non-insulin-dependent diabetes mellitus (NIDDM). Thirty male OLETF rats aged 5 weeks were assigned to one of the following three groups: trained rats placed individually in an exercise wheel (EW) cage, EW-control rats housed in the same cages equipped with a fixed rotatory wheel, and sedentary rats maintained two or three to a conventional cage. Eight male diabetes-resistant Long-Evans rats were used as nondiabetic controls. At 24 weeks of age, the trained, EW-control, sedentary, and nondiabetic control rats weighed an average of 445, 559, 621 and 513 g and had abdominal fat deposits of 16, 55, 67, and 23 g, respectively. The mean amount of exercise of trained rats was 5,243 m/d. At 24 weeks of age, the cumulative incidences of diabetes mellitus in sedentary and EW-control rats were 78% and 50%, respectively, while neither trained nor nondiabetic control rats became diabetic. Fasting and 120-minute plasma immunoreactive insulin (IRI) levels after oral glucose administration were significantly lower in the trained group than in the other groups. In vivo insulin-stimulated glucose uptake as measured with a euglycemic clamp was reduced 37% in sedentary rats and increased 35% in trained rats compared with that in nondiabetic control rats. Morphological studies on the pancreas of sedentary and EW-control rats showed enlarged multilobulated fibrotic islets, whereas sections of islets from trained rats appeared normal but slightly enlarged.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1993

Cyclophosphamide-induced diabetes in Long-Evans Tokushima Lean rats: influence of ovariectomy on the development of diabetes.

We studied the effect of treatment with cyclophosphamide (CY) on the incidence of diabetes in Long-Evans Tokushima Lean (LETL) rats, a newly established strain of spontaneously type I diabetic rats. The overall incidence of diabetes among 356 LETL rats treated with CY was 25.6%, which was significantly higher than the 10.5% among 857 untreated LETL rats at 27 weeks of age, and there was no significant sex difference. The incidence of CY-induced diabetes in adult (> 16 weeks of age) female LETL rats was 7.7% (10/130), which was significantly lower than that in other CY-treated groups of LETL rats. No diabetes mellitus was induced by administration of CY to 23 diabetes-resistant LETO rats. There were no significant differences in the degrees of hyperglycemia or hyperketonemia in spontaneously and CY-induced diabetic LETL rats, but the plasma glycated albumin level of CY-induced diabetic rats (10.3% +/- 2.1%) was significantly higher than that of spontaneously diabetic rats (8.2% +/- 1.3%), suggesting that plasma glucose levels increased more rapidly in the latter. More than half of the diabetic rats showed type C or D morphological changes of the islets, ie, atrophic change with little mononuclear cell infiltration or almost complete loss of the islets. However, distributions of various types of morphological changes in the islets were not significantly different in the two groups. Ovariectomy (OVX) significantly increased the incidence of CY-induced diabetes in adult female rats from 7.7% to 20.8%. The number of CD8+ cells was significantly increased in noncastrated adult female LETL rats and decreased to the level of other groups after OVX.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Correlation between residual beta-cell function and age at onset of spontaneous diabetes in Long Evans Tokushima lean rats.

We studied the natural course of disease in spontaneously diabetic rats, Long Evans Tokushima Lean (LETL) rats, to determine whether it showed similar pathogenetic heterogeneity to that of patients with insulin-dependent diabetes mellitus (IDDM) with regard to the relationships between age at onset, rapidity of disease progress, and degree of beta-cell function at the time of its manifestation. Type 1 diabetes developed in 35 rats (6.3%) between 40 and 140 days of age. Eight rats that became diabetic at age 69 days or less were more severely ketotic at the time of first detection of glycosuria and showed more rapid deterioration than seven rats that became diabetic later after birth (mean plasma 3-hydroxybutyrate levels, 4,707 +/- 1,215 pmol/L v 1,390 +/- 859 pmol/L; mean +/- SEM, P < .01). The mean plasma levels and pancreatic content of immunoreactive insulin (IRI) of the early onset rats, 47 +/- 13 pmol/L and 19 +/- 12 pmol/g tissue weight, were significantly lower (P < .01) than the corresponding values of the late-onset rats, 262 +/- 52 pmol/L and 348 +/- 87 pmol/g tissue weight, respectively. Both values were markedly lower than the mean values of 25 nondiabetic LETL rats, 976 +/- 122 pmol/L and 3,488 +/- 628 pmol/g tissue weight. Plasma immunoreactive glucagon (IRG) levels were significantly increased in the diabetic groups (early onset, 57 +/- 13 pmol/L; late-onset, 51 +/- 12 pmol/L; nondiabetic, 18 +/- 1 pmol/L; P < .01). These changes in pancreatic hormone levels of the early onset and late-onset rats were compatible with the histological features of their pancreatic islets.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1990

N-2 acetylation of 2'-deoxyguanosine by coffee mutagens, methylglyoxal and hydrogen peroxide.

Coffee shows direct-acting mutagenicity in Salmonella typhimurium TA100 and most of this mutagenicity is due to the synergistic effects of methylglyoxal and hydrogen peroxide. The modifications of deoxyribonucleosides by methylglyoxal plus hydrogen peroxide were studied in vitro. When 2'-deoxyguanosine (6.25 mumole) was treated with methylglyoxal (125 mumole) and hydrogen peroxide (125 mumole) in 5 ml of 0.1 M phosphate buffer (pH 7.4) at 37 degrees C for 3 h, N2-acetyl-2'-deoxyguanosine was formed with a yield of 1.1%. Its formation increased time-dependently. By contrast, no appreciable modification of other deoxynucleosides was detected after their incubation with methylglyoxal and hydrogen peroxide under similar conditions. N2-Acetyl-2'-deoxyguanosine was also formed during incubation of 2'-deoxyguanosine with instant coffee.

Acetylation↗
PubMed1989

Presence of thrombosis-inducing activity in plasma from patients with lung cancer.

Thrombosis-inducing activity (TIA) was detected in the peripheral blood of some patients with advanced lung cancer. When plasma from the patients was given intravenously to mice or to guinea pigs, the animals became immobile within 2 min and died at 3 to 30 min after the injection. Multiple thrombosis was found in the lungs and was considered to be the cause of the death. Thrombosis was not formed and the mice survived when heparin was given intravenously 5 min before the injection of the plasma. This TIA was present in plasma from 13 of 42 patients with lung cancer. On the contrary, only two of 32 with chronic lung diseases and two of 31 healthy control subjects had this activity in the plasma. The coagulation system in the 13 patients was considered to be chronically activated, as revealed by elevation of plasma fibrinogen levels, fibrin degradation product levels, and/or peripheral platelet counts. The TIA shared characteristics with tissue factor in that it was heat labile, nondialyzable through a dialysis membrane with a 10,000 molecular weight exclusion limit, sensitive to phospholipase C treatment, precipitated by 50% ammonium sulfate, and bound to concanavalin-A Sepharose.

Adenocarcinoma↗
PubMed1987

A new diet-exercise therapy in our obese-child clinic.

Because a large percentage of childhood obesity may persist into adulthood and cause a hotbed of so-called seijin-byoh (adult diseases), its treatment should also be considered from the viewpoint of seijin-byoh prophylaxis. Most obese children, however, are awkward in their movements, in spite of binge eating or bulimia, and unable to carry out any severe exercise-diet therapy. For such subjects, we have designed a new practicable procedure, and obtained excellent results for the last five years. The main principle of our procedure is that the control of caloric intake is relaxed as much as possible after due consideration of a child's growth in height: no restriction for mild, 10-15% of the requirement for moderate, and 20-25% for severe obese children, respectively. The ratio of protein/energy is established at a higher level than usual, while that of fat/energy at a lower level. For exercise, walking is the most easy and important exercise and the proper speeds for individuals are converted from the same amount of movement determined at the 1st increase point of serum lactate values, where the proportion of movement-energy originating from body fat reaches the highest percentage at about 75%. Our new procedure is supported also by the fact that the reduction in body weight combines with the improvement in measurement values of fatty metabolites without any change in values of proteins.

Adolescent↗