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Biomedical subjects

Y Kawase

Publications and source records attributed to Y Kawase.

At least 127 records · Page 7Linked to original sources
PubMed1988

Antigen-induced suppression of the proliferative response of T cell clones.

Proliferation of Ag-specific T cell clones can be inhibited by the addition of high concentrations of Ag at the beginning of culture. Under these conditions the cells produce lymphokines and express high affinity IL-2R but fail to divide, even after the addition of exogenous IL-2. This state results from restimulation of the cells with Ag-Ia molecule complexes approximately 20 h after initiation of culture. It can be prevented by addition of either an anti-Ia or an anti-L3T4 mAb at that time, but not by cyclosporin A, and mimicked in cultures containing low concentrations of antigen by addition at that time of high Ag concentrations or normal stimulatory concentrations of Con A. These observations suggest that restimulation of activated T cell clones 20 h after their initial stimulation prevents them from dividing.

Animals↗
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

Quantitative measurement of renal function using Ga-68-EDTA.

We studied renal function using a positron emission tomography with C15O gas and 68Ga-EDTA in 6 normal subjects (male, 21-77 years old). The blood volume (ml/100 g (kidney] was 19.2 +/- 1.8 for the one 21 years old subject and 11.8 +/- 2.0 for the rest (65-77 years old). The glomerular filtration rate (ml/min/100 g (kidney] was 57.8 +/- 1.1 for the 21 years old subject and 30.4 +/- 2.8 for the rest.

Aged↗
PubMed1988

[An evaluation of predicting postoperative residual liver function using 99mTc tin colloid].

The rate of clearance (K value) of 99mTc tin colloid in the liver differentiates normal subjects from liver cirrhosis patients; so 99mTc tin colloid is as useful as 198Au colloid as a marker of liver function. There are several reports concerning volume estimation using liver scintigraphy. Our original method was devised to measure the effective liver volume by scintigraphy. By combining the K value with effective liver volume, a predictive index was obtained in order to predict the residual liver function before hepatic resection. The index in 24 patients with liver diseases was investigated before hepatic resection. Three of them died due to hepatic failure after hepatic resection. The indices were between 0.40 and 0.45 in two of these three patients and 0.338 in one. Among the patients without hepatic failure, the indices showed more than 0.45 in 19 patients and between 0.40 and 0.45 in two. These results indicate that the limitation of hepatic resection is between 0.40 and 0.45 of the predictive index.

Adult↗
PubMed1988

Gastric plasmacytoma with rod-shaped intracytoplasmic inclusions. Report of a case studied by light and electron microscopy and immunohistochemistry.

A 78-year-old man with primary gastric plasmacytoma showing massive rod-shaped intracytoplasmic inclusions is presented. The patient was initially diagnosed as having a benign gastric ulcer and underwent partial gastrectomy. Around the ulcer of the resected stomach specimen, diffuse proliferation of plasma cells with massive rod-shaped intracytoplasmic inclusions was noticed by light microscopy. Immunohistochemically, these cells were found to contain IgM-kappa-type immunoglobulin upon peroxidase-antiperoxidase (PAP) staining. Electron microscopy showed that the intracytoplasmic inclusions were localized in the rough endoplasmic reticulum and had a lattice structure with a periodicity of about 120 A.

Aged↗
PubMed1987

Novel immunosuppressive agent, FK506. In vitro effects on the cloned T cell activation.

The present study shows the in vitro effects of a novel immunosuppressive agent, FK506, in comparison with cyclosporin A (CsA). FK506 inhibited concanavalin A response and allo-mixed lymphocyte reaction of murine splenic lymphocytes in a dose-dependent manner, and at 40- to 200-fold lower concentrations than CsA. Allo-cytolytic T lymphocyte induction from murine thymocytes was also inhibited by FK506, whereas the ability of cytolytic T lymphocyte to lyse targets was not affected by the agent. Immunosuppressive effects of FK506 were further characterized by using antigen specific-proliferative T lymphocyte clones, BC.21 and KO.6. FK506 inhibited the proliferation of T cell clones stimulated with specific antigens in a dose-dependent manner, and at about 100-fold lower concentrations than CsA. However, cloned T cells, once activated, were scarcely affected by the agent; interleukin-2 (IL-2) driven proliferation of cloned T cells was not inhibited. On the other hand, it was found that FK506 inhibited both IL-2 secretion and IL-2 receptor expression of BC.21 after stimulation with the specific antigen. FK506 also inhibited the proliferation of BC.21 stimulated with phorbol 12-myristate 13-acetate plus calcium ionophore, indicating that it directly affected the signaling pathway downward from the perturbation of the Ti/T3 complex. Finally, it was suggested that FK506 and CsA synergistically inhibited the antigen-driven proliferation of cloned T cells. These results indicate that the novel immunosuppressive agent, FK506, affects T cell activation with mechanisms similar to those of CsA but at considerably lower concentrations.

Animals↗
PubMed1987

Identification of I:A mismatch base-pairing structure in DNA.

Deoxyoligonucleotides containing deoxyinosine residues at positions corresponding to ambiguous nucleotides derived from an amino acid sequence have been successfully used as hybridization probes. It is assumed that the hypoxanthine residue can make base pairs with multiple bases. In order to obtain direct evidence for I:A base-pairing, a self-complementary deoxyoligonucleotide, d(G-G-I-A-C-C), was synthesized and its properties were examined by NMR spectroscopy. Three hydrogen-bonded imino proton resonances are observed at low temperatures in H2O suggesting the formation of a self-duplex with complete base pairing. Nuclear Overhauser effect (NOE) experiments showed that a signal at 15.1 ppm originated from the imino proton (H1) of the dI residue (I3) which is hydrogen-bonded to the dA residue (A4). Both the I3 and A4 residues were assumed to have taken an anti glycosidic conformation since irradiating the H1 of I3 gave NOEs both to its own H2 and to that of A4, an NOE also being observed between the H2 protons of I3 and A4. Comparison of the 31P NMR spectra of d(G-G-I-A-C-C) and d(G-G-I-C-C-C) showed the backbone structure of d(G-G-I-A-C-C) to have been disturbed by the presence of purine:purine base pairs in the middle of the hexamer duplex.

Base Composition↗
PubMed1987

Pulmonary hypertension in hepatitis B virus carriers.

Two autopsy cases of pulmonary hypertension (PH) associated with liver cirrhosis are presented. Both patients were hepatitis B (HB) virus carriers and suffered from type B cirrhosis during the clinical course. The first patient was a 52-year-old male with type B cirrhosis. He died of hepatic encephalopathy but did not have any specific symptoms for PH except abnormal laboratory findings. Chest roentgenograms displayed prominence of the central pulmonary artery. Cardiac catheterization indicated marked increment of pulmonary arterial pressure. Autopsy revealed dilatation and sclerosis of the main pulmonary artery and right ventricular hypertrophy. Microscopically, the pulmonary arteries showed intimal fibrosis, medial hypertrophy, and plexiform lesions throughout the lungs. The second patient, a 15-year-old boy, had PH with juvenile liver cirrhosis which had existed for 8 years prior to the onset of PH. He complained of severe dyspnea and dizziness before death. Electrocardiogram indicated right ventricular hypertrophy. Autopsy disclosed cardiomegaly, type B cirrhosis and sclerotic pulmonary arteries. Grade VI pulmonary plexogenic arteriopathy including plexiform lesions and necrotizing arteritis was observed. HBsAg was detected in both the hepatocytes and the pulmonary arterial walls. We discuss the possible relationship between persistent HB viral infection and PH with liver cirrhosis.

Adolescent↗
PubMed1987

[Evaluation and comparison of high-sensitivity immunoradiometric assay kits for thyroid stimulating hormone].

Fundamental and clinical characteristics of 3 kinds of high-sensitivity immunoradiometric assay (IRMA) kits for thyroid stimulating hormone (TSH). i.e., RIA BEADS II (kit A), TSH kit Daiichi II (kit B) and Ab tube TSH 'Eiken' (kit C) and one conventional radioimmunoassay (RIA) kit, i.e., TSH kit Daiichi (kit D), were studied. In the recovery test and the reproducibility test, there was no significant difference between the 4 kits. The sensitivities of kits A, B and C were much higher than that of kit D, and those IRMA kits were sensitive enough to distinguish hyperthyroidism from normal samples. For low concentrations of TSH (less than 5 microU/ml), the data from kits D, B, C and A tended to show higher values in that order. The correlation between the data measured by kits B and D, and the tendency of kit A toward lower values agreed well with other reports.

Evaluation Studies as Topic↗
PubMed1987

[Evaluation of pN factors in patients with primary lung cancer by using perfusion, inhalation and ventilation studies].

The interpretation of scintigraphic patterns and the role of pathophysiological mechanisms in patients with primary lung cancer were investigated. To determine the relative roles of perfusion, inhalation and ventilation scintigraphy, the relationship between the count ratio of the affected side to the healthy side and the post-surgical histological lymph nodes factors were observed in this study. These scintigraphic count ratio's in patients with primary lung cancer did not reflect the pN factors except in the perfusion study in patients with hilar primary lung cancer.

Humans↗
PubMed1987

On- and off-responses in photopic electroretinogram in complete and incomplete types of congenital stationary night blindness.

The on- and off-responses of photopic electroretinogram (ERG) were recorded by rectangular light stimuli in 13 patients with complete type and 9 patients with incomplete type of congenital stationary night blindness. The positive on-response (b-wave) was significantly smaller in both types than in normal subjects (P less than 0.001). The rapid off-response was normal in complete type patients, but was significantly smaller in incomplete type patients than in normal subjects (P less than 0.001). Since the rapid off-response mainly reflects the decay of the late receptor potential of the cones, incomplete type patients may have a visual disturbance in the cone itself. Normal rapid off-response with abnormal on-response in complete type patients suggests the existence of a photopic visual disturbance in the middle retinal layer. These results strongly suggest that these two types of congenital stationary night blindness have a different pathogenesis in the photopic visual pathway.

Adolescent↗
PubMed1986

Studies on nucleic acid interactions. I. Stabilities of mini-duplexes (dG2A4XA4G2-dC2T4YT4C2) and self-complementary d(GGGAAXYTTCCC) containing deoxyinosine and other mismatched bases.

The thermal stability of DNA duplexes containing deoxyinosine in a pairing position in turn with each of the four major deoxynucleotides has been investigated by measuring ultraviolet-absorbance at different temperatures. d(G2A4 X A4G2) and d(C2T4YT4C2) were prepared by the solid-phase phosphotriester method. When X is deoxyinosine, the Tm values of the duplexes are in the order Y = dC greater than dA greater than dG greater than dT greater than dU. The Tm of other duplexes containing dG, dA and dT at X were also measured. Self-complementary duplexes d(GGGAAINTTCCC) showed the same order of stability with N being dC, dA, dG and dT. Thermal stabilities of duplexes containing dG instead of dI were compared with other matched and mismatched duplexes. The Tm values of sequence isomers containing purine-pyrimidine combinations were compared. Self-complementary duplexes containing G-C and A-T in the central positions showed Tm values ca. 10 degrees higher than those containing C-G and T-A in the same positions. Thermodynamic parameters and circular dichroism spectra of these oligonucleotides were compared.

Base Composition↗
PubMed1986

A new approach to stratified normal intraocular pressure in a general population.

Using computer-filed data for approximately 187,000 eyes of 94,000 Japanese subjects who underwent automated multiphasic tests, we studied the mean and the upper limit of intraocular pressure by stratifying the whole sample by age, systolic blood pressure, and degree of obesity. Intraocular pressure increased when systolic blood pressure or obesity increased and intraocular pressure decreased with advancing age when systolic blood pressure and the degree of obesity were kept constant. Apparent disparities in the upper limit of intraocular pressure were noted between the "obese and hypertensive" and "lean and hypotensive" groups, who were at the highest and the lowest extremes, respectively. Stratified normal intraocular pressure is a standard specifically applied for different sex, age, or other systemic conditions; however, the values for the group with the highest intraocular pressure should eventually be modified by the data for Western populations.

Adult↗