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Biomedical subjects

K Amano

Publications and source records attributed to K Amano.

At least 253 records · Page 14Linked to original sources
PubMed1989

[A new apparatus using the Micro Ultra-Sonic Aspirator (MUSA) system for microneurosurgery].

Matsumoto was the first to present the NIIC UltraSonic Aspirator for CT guided stereotactic aspiration of intracerebral hematoma. Based on the NIIC Aspirator, the authors have developed a useful tool for microsurgery by adapting conventional ultrasonic aspirators. This was done by making the aspirator lighter and more handy for use during microsurgical procedures. A newly devised apparatus using the Micro Ultra-Sonic Aspirator (MUSA) was applied clinically to surgical treatment for brain tumors, arterio-venous malformations (AVMs) and intracerebral hematomas. Using the MUSA system, it became easier to remove successfully tumorous mass and the nidus of AVM, because it minimized the risk of injury to the normal structures such as the surrounding brain tissue, vascular systems and the cranial nerves.

Brain Diseases↗
PubMed1989

[A case of systemic lupus erythematosus with urticarial vasculitis].

A 37-year-old woman with SLE who presented with urticarial vasculitis is reported. Skin biopsy revealed presence of polymorphonuclear and mononuclear leukocyte infiltration, nuclear dust, extravasation of red blood cells and fibrinoid necrosis of small vessels which are characteristic features of leukocytoclastic vasculitis. In the literature, 49 cases with similar skin lesion have been reported under various terminologies including unusual SLE related syndrome, hypocomplementemia with cutaneous vasculitis and arthritis, urticarial vasculitis or hypocomplementemic vasculitic urticarial syndrome. Approximately 50% of these cases fulfilled the revised criteria for SLE. It is suggested that these cases represent a unique group of patients with characteristic skin manifestations and polyarthritis mediated by immune complex, and closely relate to SLE.

Adult↗
PubMed1989

[Venous hum and innominate vein flow velocity in chronic anemia: a pulsed Doppler echocardiographic study].

To assess the hemodynamic correlates of the cervical venous hum in patients with chronic anemia, 14 patients (mean age; 49 years, mean hemoglobin (Hb); 7.3 g/dl) and 14 control subjects (mean age; 50 years, mean Hb; 14 g/dl) without cardiac disease were studied by auscultation, phonocardiography and Doppler echocardiography in two positions (supine and sitting). Venous hum was detected in the sitting position in 11 of the 14 anemic patients whose Hb was less than 9 g/dl, and in six anemic patients in the supine position, while venous hum was absent in the control subjects in both positions. Pulsed Doppler echocardiography with the transducer in the supraclavicular fossa revealed significantly (p less than 0.01) higher peak velocity in the innominate vein in the 11 anemic patients with venous hum (supine; 71 +/- 12, sitting; 111 +/- 24 cm/sec, mean +/- SD) than in the control subjects (supine; 46 +/- 15 sitting; 76 +/- 27 cm/sec) in both positions. Intensity of venous hum increased concomitantly with increased innominate vein flow velocity when the body position was changed from supine to sitting. Peak velocity in the innominate vein correlated significantly with Hb in all study subjects (r = 0.65, p less than 0.01). In conclusion, the cervical venous hum in patients with chronic anemia is related to the hemoglobin concentration and flow velocity in the innominate vein.

Adolescent↗
PubMed1989

[Evaluation of the effect of premenopausal oophorectomy on bone mineral content].

The effects of premenopausal oophorectomy on bone mineral content (BMC) and serum parameters of bone metabolism, ie E2, PTH, Ca, P, ALP, BGP, 1-25(OH)2D3 were studied. The BMC of the spongiosum of L-3 vertebral body was calculated by means of computed tomography which was utilized in conjunction with a calibrated phantom containing a set of reference densities (CaCO3). The BMC tended to decrease markedly in the late 40s (r = -0.669, p less than 0.01) and a 38% decrease was found among the postmenopausal group (age 50-60) in comparison with the premenopausal group (age 40-49) (206.9 +/- 38.0 vs 128.5 +/- 32.7 mg/cm3, p less than 0.005). In cases of premenopausal bilateral oophorectomy (mean age 42.5) the BMC was found to decrease significantly about 2 years after the operation (150.0 +/- 25.2 mg/cm3, p less than 0.005), while no significant difference was found between the controls (mean age 43.5) and unilateral oophorectomized cases (mean age 40.3). Findings that indicated a decrease in E2, a significant increase in BGP and ALP, and a tendency for PTH to decrease were noted among bilateral oophorectomized cases and this may indicate accelerated osteogenesis. It was suggested that premenopausal bilateral oophorectomized cases are in danger of developing severe osteoporosis and are candidates for rigorous preventive treatment.

Adult↗
PubMed1989

[Hemodynamic state at rest and during maximal bicycle exercise in university students with small cardiac silhouettes on chest radiography].

To clarify the hemodynamic state of an apparently small heart; i.e., a small cardiac silhouette on chest radiography, chest radiographic and echocardiographic studies, physical fitness tests (a battery of tests consisting of vertical jump, side step, floor push-up, and modified Harvard step test) and graded uninterrupted bicycle exercise test were performed. 1. The cardiothoracic ratio (CTR) in 3,461 newly-enrolled university students (18.7 +/- 1.2 years old: mean +/- SD) distributed normally and the mean value +/- SD was 40.2 +/- 3.6%. No difference was observed between male and female students. 2. A small heart was defined as one having a cardiothoracic ratio (CTR) less than or equal to 35% which comprised the lower 10% of the normal distribution. There was no significant difference in results of physical fitness tests between students with small heart (n = 134) and normal controls (n = 136, 45% less than or equal to CTR less than or equal to 50%). 3. A maximal bicycle exercise test was performed in 14 male students with small heart (S: CTR = 31.9 +/- 2.1%) and nine normal controls (C: CTR = 46.5 +/- 1.0%). a) Body weight (S: 57 +/- 7, C: 69 +/- 8 kg, p less than 0.001) were less in students with small heart; Body height was similar in both categories (S: 171 +/- 5, C: 175 +/- 7 cm, NS). b) All controls finished 200 W workload, whereas all students with small heart ceased exercise earlier than the control subjects (three at 125 W, three at 150 W, eight at 175 W). c) Resting heart rate was higher in cases with small heart (S: 92 +/- 14, C: 77 +/- 10 beats/min, p less than 0.02). Left ventricular end-diastolic dimension was smaller in small heart (S: 39 +/- 4, C: 48 +/- 4 mm, p less than 0.001). d) During exercise, blood pressure and oxygen intake at the same workload were similar in both groups, but peak oxygen uptake was higher in the controls (S: 43 +/- 5, C: 50 +/- 7 ml/kg/ml, p less than 0.05). Heart rate and blood lactate concentration were higher throughout exercise in students with small heart (lactate at 175 W; S: 12.7 +/- 1.6, C: 7.8 +/- 2.0 mmol/L, p less than 0.001) (heart rate at 175 W; S: 194 +/- 6, C: 173 +/- 21 beats/min, p less than 0.05). We concluded that hemodynamic conditions at rest and during low grade exercise are preserved in students with small heart.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1989

Intestinal parasitic infections among schoolchildren in Chiang Mai, northern Thailand: an analysis of the present situation.

Stool examination from primary schoolchildren in Chiang Mai Province, north Thailand, was performed to determine the present state of parasitic infections in this area. Out of a total of 491 children, 239 proved positive (48.7%). The most common type of parasite was found to be soil-transmitted helminths such as hookworm (26.3%) or Strongyloides stercoralis (11.2%), while Ascaris lumbricoides was not so prevalent (1.2% being positive in one school out of three). These results are in contrast to earlier reports showing higher prevalence rates, leading the authors to hypothesize that improvements in sanitary conditions and eradication projects have been effective. Opisthorchiasis is another parasitic disease with a relatively high prevalence rate of 7.5%. This disease rate increases with age and it was found in two out of three schools (8.3-15.8%) and was the most common type of helminth infection. Ascariasis was not seen in these two schools, but strongyloidiasis was found to be the second most prevalent helminthiasis, having a higher infection rate than hookworm. Therefore, eradication efforts now need to be directed toward eliminating opisthorchiasis and strongyloidiasis in addition to continuing to eradicate ascariasis and hookworm infections. The most common protozoal infection with a high pathogenicity in this region was found to be giardiasis (7.7%).

Adolescent↗
PubMed1988

Insulin-degrading enzyme is capable of degrading receptor-bound insulin.

In the investigation of the intracellular sites of insulin degradation, it might be important whether receptor-bound insulin could be a substrate for insulin-degrading enzyme (IDE). Insulin receptor and IDE were purified from rat liver using a wheat germ agglutinin column and monoclonal anti-IDE antibody affinity column, respectively. [125I]insulin-receptor complex was incubated with various amounts of IDE at 0 degree C in the presence of disuccinimidyl suberate and analyzed by reduced 7.5% SDS-PAGE and autoradiography. With increasing amounts of IDE, the radioactivity of 135 kd band (insulin receptor alpha-subunit) decreased, whereas that of 110 kd band (IDE) appeared then gradually increased, suggesting that IDE could bind to receptor-bound insulin. During incubation of insulin-receptor complex with IDE at 37 degrees C, about half of the [125I]insulin was dissociated from the complex. However, the time course of [125I]insulin degradation in this incubation was essentially identical to that of free [125I]insulin degradation. Cross-linked, non-dissociable receptor-bound [125I]insulin was also degraded by IDE. Rebinding studies to IM-9 cells showed that the receptor binding activity of dissociated [125I]insulin from insulin-receptor complex incubated with IDE was significantly (p less than 0.001) decreased as compared with that without the enzyme. These results, therefore, show that IDE could recognize and degrade receptor-bound insulin, and suggest that IDE may be involved in insulin metabolism during receptor-mediated endocytosis through the degradation of receptor-bound insulin in early neutral vesicles before their internal pH is acidified.

Animals↗
PubMed1988

Prevention of lymphocytic thyroiditis and insulitis in diabetes-prone BB rats by the depletion of macrophages.

Diabetes-prone biobreeding (BB) rats often develop lymphocytic thyroiditis. Intraperitoneal administration of silica to young BB rats (40-days-old) nearly completely prevented the development of lymphocytic thyroiditis as well as insulitis. Since silica is known to be toxic to macrophages, these data suggest that the presentation of autoantigen(s) on the specific target cells such as thyroid and pancreatic B cells by antigen-presenting cells (e.g., macrophages) would be the initial step in the development of organ-specific autoimmune diseases in diabetes-prone BB rats.

Animals↗
PubMed1988

IgA deposition in alcoholic liver disease. An immunoelectron microscopic study.

The ultrastructural localization of IgA, IgA1, and IgA2 deposited on liver tissues from 13 patients with alcoholic liver disease and 9 patients with nonalcoholic liver diseases was investigated by the immunoperoxidase method. A continuous pattern of IgA deposition along the perisinusoidal area was observed not only in the alcoholic patients but also in the nonalcoholic patients. Ultrastructurally, IgA deposits were seen on the plasma membranes of Kupffer cells, endothelial cells, and hepatocytes and in the endocytotic vesicles and phagosomes of Kupffer cells and endothelial cells. In the alcoholic group, deposits of IgA on collagen fibers were observed at sites where pericellular fibrosis developed but, on the other hand, IgA deposits were diminished or absent on the plasma membranes of hepatocytes. IgA1 showed the same deposit pattern as IgA. IgA2 was observed on and in Kupffer cells and endothelial cells but was not detected on the plasma membranes of hepatocytes. From these studies, the authors conclude that IgA deposition in the liver is not specific for alcoholic liver disease but may reflect the reduced metabolism of damaged liver. An additional finding was that, of the IgA subclasses, only IgA1 combined with the plasma membranes of hepatocytes.

Hepatitis↗
PubMed1988

Identification of antigenic differences between the diabetogenic and non-diabetogenic variants of encephalomyocarditis virus using monoclonal antibodies.

The M variant of encephalomyocarditis (EMC) virus consists of two biologically distinct variants: one, diabetogenic D variant (EMC-D) and the other, non-diabetogenic B variant (EMC-B). These two variants cannot be distinguished by hyperimmune sera. Monoclonal antibodies were generated against EMC-D or EMC-B to identify antigenic differences between these two variants. Fourteen independent hybrid cell lines, selected from seven separate fusions of mouse myeloma cells to spleen cells isolated from mice immunized with EMC-D, consisted of 12 hybrids which produced monoclonal antibodies that neutralized both EMC-D and EMC-B, and two hybrids (ED-HJ-23 and ED-HJ-31) which produced monoclonal antibodies that neutralized EMC-D but not EMC-B. Similarly, 16 independent hybrid cell lines, selected from eight separate fusions using spleen cells prepared from mice immunized with EMC-B, consisted of 15 hybrids which produced monoclonal antibodies neutralizing both EMC-D and EMC-B, and one hybrid (EB-48A-F1) which produced antibody that neutralized EMC-B, but not EMC-D. The specificities of these monoclonal antibodies (ED-HJ-23, ED-HJ-31, EB-48A-F1) were further confirmed using an immunofluorescent technique. The D variant-specific monoclonal antibodies reacted with cells infected with EMC-D but not EMC-B. In contrast, the B variant-specific monoclonal antibody reacted with the cells infected with EMC-B but not EMC-D. It is concluded that the EMC-D- and EMC-B-specific monoclonal antibodies are able to identify antigenic differences between diabetogenic and non-diabetogenic variants of EMC virus which cannot be distinguished by hyperimmune sera.

Animals↗
PubMed1988

Assessment of the thickness of the right ventricular free wall by magnetic resonance imaging in patients with hypertrophic cardiomyopathy.

Electrocardiogram gated magnetic resonance imaging was performed in nine healthy volunteers, in four patients with pulmonary hypertension, and in 16 patients with hypertrophic cardiomyopathy. Fifty two short axis images in diastole were examined to assess the usefulness of magnetic resonance imaging for the measurement of the thickness of the free wall of the right ventricle and the degree of hypertrophy of the right ventricular free wall in hypertrophic cardiomyopathy and pulmonary hypertension. Magnetic resonance imaging gave a clear image of 68% of the length of the right ventricular free wall, showing both the endocardial and epicardial margins. The mean (1 SD) thickness of the right ventricular free wall measured at a total of 512 points was 0.44 (0.12) cm in patients with hypertrophic cardiomyopathy, 0.29 (0.08) cm in healthy individuals, and 0.73 (0.27) cm in patients with pulmonary hypertension.

Cardiomyopathy, Hypertrophic↗
PubMed1988

Capillary permeability and boron distribution in ethylnitrosourea-induced rat glioma.

The vasculature and capillary permeability of gliomas induced by ethylnitrosourea in Sprague-Dawley rats were studied with horseradish peroxidase and Evans blue dye. The distribution of the boron-10 compound, Na2(10)B12H11SH, which is now in clinical use for boron neutron capture therapy (BNCT) for brain tumors, was investigated quantitatively using neutron-induced alpha-autoradiography. The vasculature and the degree of capillary permeability varied widely, depending mainly on the size of the glioma, and were often heterogeneous even in the same tumor. The distribution of boron-10 also varied, correlating to capillary permeability. The boron-10 concentration and the tumor:blood concentration ratio in large and medium-sized gliomas were adequate for successful BNCT. This study suggests that the vasculature and capillary permeability of the target brain tumor exert an important influence on the therapeutic efficacy of BNCT.

Animals↗
PubMed1988

Evidence for initial involvement of macrophage in development of insulitis in NOD mice.

Macrophages have been shown to be the major population of infiltrated immunocytes at the early stage of insulitis in diabetes-prone BB rats. This study was undertaken to investigate the role of macrophages in the development of insulitis in nonobese diabetic (NOD) mice. Administration of cyclophosphamide to NOD mice resulted in a significant increase in the incidence of overt diabetes and severity of insulitis compared with that in untreated NOD mice. Intraperitoneal injections of silica completely prevented the development of diabetes and insulitis in both cyclophosphamide-treated and untreated animals. Because silica is selectively toxic to macrophages, the results suggest that macrophages play an important role in the initiation of insulitis in NOD mice.

Animals↗