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Biomedical subjects

A Yoshida

Publications and source records attributed to A Yoshida.

At least 793 records · Page 44Linked to original sources
PubMed1990

Estimation of permeability in blood-retinal barrier.

Permeability of the blood-retinal barrier (BRB) can be determined by vitreous fluorophotometry and computer analysis. In this study, we characterize our eye model and apply it to normal human subjects. In this investigation of BRB permeability, we employed four parameters for the eye model: the inward permeability (Pin) and outward permeability (Pout) of the BRB; the diffusion coefficient in the posterior vitreous gel (D-p); and the plasma fluorescein concentration. The values of Pin, D-p, and plasma fluorescein concentration significantly affected the fluorescein concentration in the posterior vitreous 60 minutes after intravenous fluorescein injection. The value of Pout had little influence on the fluorescein kinetics in the posterior vitreous 60 minutes after injection. The results of experiments on humans indicate that the estimated values obtained by simulation fit satisfactorily the measured values. It is suggested that our computer simulation method in conjunction with vitreous fluorophotometry can effectively estimate permeability of BRB in normal and pathological eyes.

Adolescent↗
PubMed1990

Vitreous changes and macular edema in central retinal vein occlusion.

The condition of the posterior vitreous was determined in 56 eyes with central retinal vein occlusion (CRVO). Using a life-table analysis, it was studied in 56 eyes. The incidence of posterior vitreous detachment (PVD) in the CRVO eyes at the first vitreous examination did not differ significantly from that in 64 age-matched control eyes. However, the incidence of PVD in CRVO eyes increased from 39.3% at the first vitreous examination to 58.5% after 6 months, and to 69.6% 1 year from the examination. The incidence of PVD in CRVO eyes during follow-up was statistically higher than that of the controls (P = .009). The incidence of PVD after the first vitreous examination was significantly higher in eyes with hemorrhagic retinopathy than in eyes with venous stasis retinopathy (P = .04). In the 34 eyes with macular edema, the edema lasted significantly longer in those with vitreomacular attachment (VMA) at the first examination than in those without VMA at this time (P = .02). VMA may play an important role in the pathogenesis and chronicity of macular edema in CRVO.

Adult↗
PubMed1990

Nodular glomerulosclerosis in a patient showing impaired glucose tolerance.

We report a case showing typical diabetic nodular glomerulosclerosis without retinopathy or other apparent clinical findings of DM except for impaired glucose tolerance. The 57-year-old man had a family history but no personal history of DM. In an extensive examination for DM, the results of funduscopy, daily profile of serum glucose and hemoglobin Alc were entirely within normal limits. However, the oral glucose tolerance test was abnormal. A renal biopsy showed typical nodular lesions (Kimmelstiel-Wilson's lesions). Previously, the interesting feature of transient proteinuria had been recognized. Although hypocellular nodular lesions by light microscopy are characteristic of diabetic nephropathy, renal amyloidosis, carbon disulfide intoxication, multiple myeloma and light chain disease, we concluded that the present lesions had resulted from diabetic nephropathy based on the family history, patient history, impaired glucose tolerance, immunofluorescent findings and electron microscopic observations.

Diabetic Nephropathies↗
PubMed1990

[Indium-111 antimyosin monoclonal antibody uptake in patients with cardiomyopathy and myocarditis].

Prognostic significance of myocardial uptake of indium-111 antimyosin antibody was evaluated in 17 patients with idiopathic cardiomyopathy; 10 patients with dilated cardiomyopathy and 7 patients with hypertrophic cardiomyopathy. Seven of 10 patients with dilated cardiomyopathy showed positive images. Three of these 7 patients with strongly positive scans died after scintigraphic examination. Six of 7 patients with hypertrophic cardiomyopathy showed positive images. Three of the patients with dilated left ventricle had prominent positive scans and higher heart to lung ratio. The heart to lung ratio of antimyosin uptake in total patients was correlated with left ventricular end-diastolic dimension and ejection fraction measured by echocardiography. In patients with myocarditis, all three patients showed positive scintigrams within 4 weeks after the onset of the disease and 1 of 6 patients was positive thereafter, who had dilated ventricle and decreased cardiac function. Thus, indium-111 antimyosin antibody imaging may be useful to evaluate prognosis of patients with cardiomyopathy and myocarditis.

Adult↗
PubMed1990

[A case-control study of the etiologic factors of a multiple primary cancer following a prior first breast cancer].

At the Kanagawa Cancer Center, the cases of 48 women who were found to have a multiple primary cancer (MPC) and who had previously had a first breast cancer (FBC) were reviewed, and a hospital-based, matched-pair, case-control study was performed. Studied were the effects of the reproductive factors, the therapies for their FBC, their drinking and smoking habits, and similar criteria on the development of the MPC. The case-control pairs were matched for age, year of their FBC diagnosis, and place of residence. The controls had only breast cancer and each lived beyond the MPC patient with whom they had been matched. The odds ratios for radiation therapy and drinking habits, calculated by McNemar's Test, were 4.00 (95% CI = 1.06-17.82) and 8.00 (1.03-170.60), respectively.

Adult↗
PubMed1990

[Membranous obliteration of the inferior vena cava in the hepatic portion--postmortem study of a rapidly deteriorated aged case].

A 67-year-old female of Budd-Chiari syndrome was rapidly deteriorated and died. Autopsy revealed membranous obliteration of the inferior vena cava in the hepatic portion with a small hole. The inferior vena cava and right hepatic vein contained fresh and organized thrombi. The left hepatic vein was patent and opened above the membrane. The onset and the clinical course of this case seem to be atypical, probably because of the patent left hepatic vein and a small hole of the membrane. We call attention such a rare case in managing Budd-Chiari syndrome.

Aged↗
PubMed1990

High resolution computed tomography of auditory ossicles.

Auditory ossicular sections were scanned at section thicknesses (mm)/section interspaces (mm) of 1.5/1.5 (61 patients), 1.0/1.0 (13 patients) or 1.5/1.0 (33 patients). At any type of section thickness/interspace, the malleal and incudal structures were observed with almost equal frequency. The region of the incudostapedial joint and each component part of the stapes were shown more frequently at a section interspace of 1.0 mm than at 1.5 mm. The visualization frequency of each auditory ossicular component on two or more serial sections was investigated. At a section thickness/section interspace of 1.5/1.5, the visualization rates were low except for large components such as the head of the malleus and the body of the incus, but at a slice interspace of 1.0 mm, they were high for most components of the auditory ossicles.

Adolescent↗
PubMed1990

[Clinical trial of 111In-antimyosin antibody imaging: (4). Effect of reperfusion in acute myocardial infarction].

Effects of reperfusion by intra-coronary thrombolysis (ICT) or percutaneous transluminal coronary angioplasty (PTCA) on the myocardial imaging using 111In-labeled antimyosin monoclonal antibody Fab (In-AM) were studied. Reperfusion by ICT or PTCA was done in 16 patients (reperfusion group) and recanalization was seen in 14. Positive images were obtained in 28 of 30 patients (93%) with acute myocardial infarction (onset to imaging: 9.9 +/- 9.8 days). Among the reperfusion group, one patient in whom PTCA was done early after the onset of chest pain and CPK did not elevate showed no significant uptake of radioactivity at cardiac region, while other 15 patients with elevation of CPK demonstrated positive images. Planar images (anterior, left anterior oblique 45 degrees, left lateral) were divided into 15 segments and infarct size (antimyosin-segment) was determined by sum of positive segments on each image. There were no significance between the infarct size in the reperfusion group (7.2 +/- 2.9) and that in the non-reperfusion group (6.9 +/- 3.4). Intensity of the accumulation of radioactivity in each image was classified into 5 grades by comparison with uptake of the liver (antimyosin-score). Reperfusion group demonstrated high intensity compared with non-reperfusion group (2.6 +/- 0.7 vs. 2.0 +/- 0.4; p less than 0.05). Thus, In-AM imaging may be influenced by coronary blood flow, which should be taken into consideration in the interpretation of In-AM imaging.

Adult↗
PubMed1990

[Role of the vitreous in idiopathic preretinal macular fibrosis indicated by visual acuity in follow-up cases].

The vitreous and visual acuity in 103 eyes with idiopathic preretinal macular fibrosis were examined. The vitreous was studied biomicroscopically and the follow-up course was 6 months or more. Twenty-two eyes had no posterior vitreous detachment (group 1), 4 eyes had partial posterior vitreous detachment without traction to the macula (group 2), 17 eyes had partial posterior vitreous detachment with traction to the macula (group 3), and 60 eyes had complete posterior vitreous detachment (group 4). There were significantly more eyes with a visual acuity of 0.4 or worse, decreased acuity, or macular fluorescein leakage in group 3 than in groups 1 or 4. Decreased visual acuity was found in 41% of eyes with macular fluorescein leakage, but in only 11% of eyes without macular fluorescein leakage. It is presumed that the vitreous traction to the macula and macular fluorescein leakage are closely related to the outcome of visual acuity in cases with idiopathic preretinal macular fibrosis.

Adolescent↗
PubMed1990

[Megakaryocytic leukemia cell lines and megakaryocytic leukemia].

Using the megakaryocytic leukemia cell lines, K-562 and CMK established from a Down's patient with acute megakaryoblastic leukemia, we studied the changes of antigen expression, cytosolic Ca2+ mobilization, thromboxane (TX) A2 formation and gene expression during megakaryocyte differentiation. We found that thrombospondin synthesis and platelet factor (PF)-4 gene expression were specific for mature megakaryoblasts, whereas collagen unresponsiveness and prostaglandin E1-induced Ca2+ mobilization were noted in immature megakaryoblasts alone. This experiment shows that functional and genetic analysis are useful for characterizing the leukemic megakaryoblastic cells. We analyzed the clinical, hematologic and genetic features of 4 patients with M7, and acute megakaryoblastic transformation of CML, MDS and essential thrombocythemia. In two patients, prednisolone and 6-MP were effective in cytoreduction. In 3 patients with increased platelet counts, normal CFU-Meg formation, the megakaryoblasts with platelet production, or the coexistence of immature megakaryoblasts with mature megakaryocytes were observed, thus indicating that some megakaryoblastic leukemia cells still have the capacity of differentiation. One patient had megakaryoblastic cells with PF-4 gene expression. These clinical findings suggest that the megakaryoblastic leukemia could not be characterized as usual leukemia and a more sensitive marker is required to differentiate leukemic megakaryoblasts from normal megakaryoblasts.

Aged↗
PubMed1990

[An anti-human eosinophil monoclonal antibody AE500 that reacts only with granulocytes from hypereosinophilic patients].

To investigate the heterogeneity of human eosinophils, we established a murine anti-human eosinophil monoclonal antibody AE500 (IgM, kappa) by immunizing blood eosinophils from patients with idiopathic eosinophilia. The reactivity of AE500 with human leukocytes was analyzed by a fluorescence-activated cell sorter. AE500 reacted with all the populations of blood eosinophils and neutrophils from patients with eosinophilia (idiopathic eosinophilia, n X 4 or asthma, n =), but not with those from asthmatic patients without eosinophilia (n = 8) or normal subjects (n = 6). AE500 did not react with granulocytes from other family members of AE500-positive individuals. These results suggest that the anti-human eosinophil antibody AE500 reacts with a cell surface antigen of blood granulocytes in a hypereosinophilic state. This anti-eosinophilic antibody would be useful in investigating the mechanism of eosinophilia in a variety of diseases.

Antibodies, Monoclonal↗
PubMed1989

Physiological and morphological characteristics of periodontal mesencephalic trigeminal neurons in the cat--intra-axonal staining with HRP.

Intra-axonal recording and horseradish peroxidase (HRP) injection techniques were employed to define the response properties of periodontal mechanoreceptive afferents originating from the trigeminal mesencephalic nucleus (Vmes) and their morphological characteristics. The periodontal Vmes neurons were classified into two types: slowly adapting (SA) and fast adapting (FA) types. The central terminals of 7 SA and 4 FA afferents were recovered for detailed analyses. The whole profile of SA and FA neurons were unipolar in shape and their cell bodies were located in the dorsomedial parts of the Vmes. The united (U) fiber traveled caudally from the soma to the dorsolateral aspect of the trigeminal motor nucleus (Vmo), where it split into the peripheral (P) and C fibers with a T- or Y-shaped appearance. The P fiber joined the trigeminal sensory or motor tract. The C fiber descended caudally within Probst's tract. All 3 stem fibers issued main collaterals. The main collaterals of all neurons examined formed terminal arbors in the supratrigeminal nucleus (Vsup) and all but two SA neurons projected to the intertrigeminal region (Vint), while the projections to other nuclei of the trigeminal motor nucleus (Vmo), juxtatrigeminal region (Vjux), main sensory nucleus (Vp) and oral nucleus (Vo.r) differed between SA and FA afferents and between neurons of the same type. The SA and FA neurons were classified into three and two subgroups, respectively. The major differences in central projections between the two types were that all the FA neurons projected to the Vp or Vo.r but none of SA type and this relation was reversed in the projection to the Vjux, and that more than half of SA neurons projected to Vmo but only one FA neuron to the Vmo. The Vmes neurons which sent their collaterals into the Vmo had the P fiber passing through the tract of the trigeminal motor nerve. The average size of somata and mean diameters of U fibers and main collaterals from C fiber were significantly larger in SA neurons than FA neurons. The average size of fiber varicosities became smaller in the following nuclei, Vmo, Vsup, Vp, Vint and Vo.r, but not significant between the two functional types. The functional role of the periodontal Vmes afferents to jaw reflexes was discussed particularly with respect to their central projection sites in the brainstem nuclei.

Action Potentials↗
PubMed1989

Two structural genes on different chromosomes are required for encoding the major subunit of human red cell glucose-6-phosphate dehydrogenase.

Structural analysis revealed the existence of two types of subunits in human red cell glucose-6-phosphate dehydrogenase. The two subunits have the same COOH region consisting of 479 amino acid residues, but their NH2-terminal regions are different in size and sequence. The minor subunit can be fully encoded by the X-linked G6PD cDNA, but the NH2-terminal region of the major subunit cannot. The cDNA and the gene for the NH2-terminal region of the major subunit were cloned and characterized. Southern blot hybridization indicated that the gene for the NH2-terminal region is on chromosome 6, not on the X chromosome. Northern blot hybridization demonstrated an existence of two separate mRNA components, one for the COOH-terminal region and the other for the NH2-terminal region. Two separate structural genes, the X-linked and chromosome 6-linked genes, must be coresponsible for encoding the single chain subunit. Either cross-translation of two mRNAs, or transpeptidation, or some other mechanism must be involved in the synthesis of human red cell G6PD.

Amino Acid Sequence↗
PubMed1989

Elevation of intracellular calcium ion by prostaglandin E1 and its inhibition by protein kinase C in a human megakaryocyte leukemia cell line.

In the present study, we examined the effect of prostaglandin E1 (PGE1) on Ca2+ mobilization in a human megakaryocyte (the progenitor of platelets) leukemia cell line, designated as CMK. PGE1 caused a rapid and dose-dependent increase in the intracellular free calcium level ([Ca2+]i) associated with the elevation of cyclic AMP. The PGE1-induced elevation of [Ca2+]i was decreased by the prior addition of ethylene glycol bis(2-aminoethylether)tetraacetic acid to the medium by approximately 25% of the control. This result indicates that the PGE1-induced elevation of [Ca2+]i is due to influx of Ca2+ from the external medium and to mobilization of Ca2+ from intracellular stores. Pretreatment of CMK cells with 12-O-tetradecanoylphorbol-13-acetate (TPA), a stimulus for protein kinase C, further enhanced the PGE1-induced increase in the cellular cyclic AMP level. Inversely, pretreatment of CMK cells with TPA (10 nM), prior to the addition of PGE1, inhibited the PGE1-induced elevation of [Ca2+]i. Dibutyryl cyclic AMP and forskolin did not elevate [Ca2+]i or affect the PGE1-induced Ca2+ mobilization. The inhibitory action of TPA in the PGE1-induced elevation of [Ca2+]i was mimicked by other protein kinase C-activating agents, such as 1-oleoyl-2-acetylglycerol and N-(6-phenylhexyl)-5-chloro-1-naphthalenesulfonamide, and was selectively restored by protein kinase C inhibitors, such as 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride and N-[2-(methylamino)ethyl]-5-isoquinolinesulfonamide dihydrochloride. Thus, the inhibitory modulation of TPA on the PGE1-induced elevation of [Ca2+]i is mediated through protein kinase C activation. PGE1 had no inductional effect of megakaryocytic phenotypic changes in CMK cells. The biological role of PGE1, which increased [Ca2+]i and cyclic AMP levels in the CMK cells, remains to be determined.

Alprostadil↗
PubMed1989

[MR imaging of orbital tumors].

Nine cases of pathologically confirmed orbital tumors were evaluated with magnetic resonance imaging (MRI) at 0.5T. Seven cases were examined with orbit-coil using 7-mm-thick sections and two cases were examined with head-coil using 10-mm-thick sections. All lesions were clearly demonstrated on T1-weighted images as low intensity. However, the lesions were indistinct on T2-weighted images because of low contrast between the lesions and surrounding orbital fat and artefact produced by eye movement. Two of three cases with meningioma examined with orbit-coil were clearly discriminated from the optic nerve. Meningioma in the remaining case examined with head-coil was discriminated from the optic nerve by administration of Gd-DTPA. Adenoma of the right lacrimal gland was shown as an enlarged gland on T1-weighted images. Pseudotumors (four cases) showed very low intensity on T1-weighted images. Three cases of four pseudotumors showed low intensity on T2-weighted images. Among them one was moderately low intensity, and histological examination of the lesion showed prominent fibrotic changes. Pseudotumor of the remaining case examined with the head-coil showed same intensity with fat on T2-weighted images. Intraorbital infiltrating foci of chronic lymphocytic leukemia showed low intensity with fat on T1-weighted images, and the same intensity with fat on T2-weighted images. MRI may be useful to discriminate pseudotumor with fibrotic changes (chronic inflammatory lesions) from lymphoma or leukemic infiltration.

Adenoma↗