Biomedical subjects

Y Ueki

Publications and source records attributed to Y Ueki.

At least 19 recordsLinked to original sources

PubMed1992

Purification and structural analysis of hippocampal cholinergic neurostimulating peptide.

Hippocampal soluble fraction stimulates acetylcholine (AcCho) synthesis of medial septal nuclei in explant culture system. This stimulating activity was purified from 10-12-day-old rat hippocampus. During purification, the activity was separated into two fractions and a previously unreported peptide was purified from one fraction. The structure of this novel peptide is acetyl-Ala-Ala-Asp-Ile-Ser-Gln-Trp-Ala-Gly-Pro-Leu and we designated it as hippocampal cholinergic neurostimulating peptide (HCNP). Synthesized HCNP and de-acetylated HCNP (free-HCNP) stimulated AcCho synthesis of medial septal nuclei culture, in a dose-dependent manner, but not cultures of corpus striatum or anterior spinal cord. Mean half-maximal concentrations of HCNP and free-HCNP in AcCho synthesis of medial septal nuclei culture were 1.0 +/- 0.3 x 10(-10) M and 1.0 +/- 0.6 x 10(-11) M, respectively. Affinity purified polyclonal antibody to the free-HCNP neutralized the activity of crude hippocampal extract, as well as synthetic HCNP and free-HCNP. These observations suggested that HCNP was present in the hippocampal extract and was involved in development of specific cholinergic neuron in central nervous system.

Amino Acid Sequence↗

PubMed1992

Remarkable increase in CD26-positive T cells in patients with human T lymphotropic virus type I (HTLV-I) associated myelopathy.

We used two-color flow cytometric analysis to investigate CD26+ (Ta1+) cells in peripheral blood T lymphocytes from patients with human T-lymphotropic virus type-I (HTLV-I)-associated myelopathy (HAM). The percentage of CD26+ cells among CD3+ cells was markedly increased in patients with HAM, compared with anti-HTLV-I seropositive carriers (p < 0.001) and seronegative controls (p < 0.01). Within the subpopulation of T cells, a significantly high percentage of CD26+ cells was detected in both CD4+ and CD8+ cell populations. Furthermore, analysis of HLA-DR+ T cells revealed similar results. In contrast CD4+CD45RA+ cells were significantly decreased in comparison with controls. These results suggest that immunologically activated or memory T cells found in peripheral blood may be etiologically relevant to HAM.

Adult↗

PubMed1992

[Effects of gamma-hydroxybutyrate on monoamine metabolism and protein synthesis after transient global cerebral ischemia].

The effects of gamma-hydroxybutyrate (GHB) on 1) monoamine metabolism, and 2) protein synthesis were examined in a gerbil stroke model. The monoamine metabolism was studied by occluding bilateral common carotid arteries for 15 minutes followed by GHB administered intravenously 3 hours later. Tissue monoamine concentration was examined up to 8 hours after recirculation. Three hours after GHB administration, dopamine (DA) had increased to almost twice that of the non-treated group, whereas homovanillic acid, a metabolite of DA, did not show any significant difference. These results may mean that GHB will facilitate DA synthesis but that it has no influence on its release. Therefore, a DA-mediated increase in cerebral blood flow in the cerebral cortex cannot be expected. Tryptophan, a precursor of 5-hydroxytryptamine (5HT), started to increase just after recirculation reaching a level of over four times that of the control value at 2 to 3 hours, and then starting to decrease in the non-treated group. This decline in tryptophan was markedly facilitated by GHB administration within 1 hour. On the other hand, 5HT administration within 1 hour. On the other hand, 5HT increased only very slightly in the cerebral cortex 1 hour after GHB administration, the change ratio being 1/30 of tryptophan. It can therefore be speculated, that the decrease in tryptophan brought about by GHB administration is due to the improvement in disturbed protein synthesis rather than to stimulation of 5HT synthesis. Protein synthesis was studied by administering GHB 2 minutes prior to a 5-minute temporal common carotid artery occlusion. Ninety minutes after recirculation animals were given a single dose of 14C-leucine and further 60 minutes were allowed to pass before sacrifice. Autoradiographs of the GHB-treated group were compared with those of the non-treated group. With GHB pretreatment, autoradiographs showed an increased uptake of 14C-leucine in at least the hippocampus, thalamus, and hypothalamus, and in two out of three animals, there was diffusely increased uptake. Thus, it is speculated that GHB is effective in improving the protein synthesis in the postischemic period. The favorable function of GHB during cerebral ischemia is regarded by many to be prevention of energy failure by reducing cerebral metabolism. On the other hand, the results derived from the present study suggest that GHB may improve protein synthesis in the postischemic period. Thus, we suggest that GHB is useful if given at the acute stage of cerebral ischemia such as during internal carotid artery or middle cerebral artery occlusion.

Animals↗

PubMed1991

Effects of lobenzarit disodium on human endothelial cells. Lobenzarit disodium inhibits proliferative response, HLA-DR antigen expression, and T cell adherence toward endothelial cells.

The therapeutic action of lobenzarit disodium (CCA) on the function of endothelial cells (EC) isolated from human umbilical cord veins was investigated. CCA suppressed 3H-thymidine incorporation into EC in a dose-dependent manner. Significant inhibition was detected at a concentration of 50 micrograms/ml. The expression of HLA-DR antigen on the surface of EC was increased when EC were cultured with recombinant interferon-gamma (rIFN gamma). Treatment of EC with either IFN gamma or interleukin-1 enhanced the adhesion of T cells to EC. The kinetics of HLA-DR antigen expression by EC cultured with IFN gamma was different from the kinetics of T cell-EC adhesion, however. Neither anti-HLA-DR nor anti-HLA-ABC monoclonal antibody inhibited T cell binding to EC monolayers. CCA suppressed the expression of HLA-DR antigen by EC cultured with rIFN gamma. In an EC monolayer adhesion assay, CCA also inhibited T cell adhesion to EC in the presence of either IFN gamma or interleukin-1. Significant inhibition was observed at a CCA concentration of 10 micrograms/ml, a level that is easily attainable in serum. These results suggest that CCA may suppress rheumatoid synovitis by reducing the angiogenesis and emigration of chronic inflammatory cells from the blood into the synovium.

Cell Adhesion↗

PubMed1991

Synergistic effects of phorbol ester and interferon-alpha: target cell class I HLA antigen expression and resistance to natural killer and lymphokine-activated killer cell-mediated cytolysis.

This study was undertaken to investigate whether target cell class I HLA antigen expression induced by phorbol ester and interferon-alpha (IFN-alpha) was associated with resistance to natural killer (NK) cells and lymphokine-activated killer (LAK) cell-mediated cytotoxicity. Class I antigen expression on the surface of the K562 erythroleukemia cell line was enhanced by either IFN-alpha or phorbol ester (PDBu). Addition of PDBu together with IFN-alpha had a synergistic effect on class I antigen expression on the cells. Furthermore, synergism between IFN-alpha and PDBu was also found in class I antigen expression by MOLT-3 cells. This synergistic effect on class I antigen expression was blocked by the protein synthesis inhibitor (cycloheximide). Pretreatment of K562 cells with PDBu and IFN-alpha made them more resistant to lysis by NK and LAK cells than did either PDBu or IFN-alpha. In contrast to PDBu, 4 alpha PDD, a biologically inactive phorbol analogue, alone or combination with IFN-alpha, had no effect on class I antigen expression and susceptibility to lysis by NK and LAK cells. Kinetic experiments showed an inverse relationship between the expression of class I antigens and susceptibility to NK cell-mediated cytolysis. Using cold target competition analysis, target cells pretreated with PDBu and IFN-alpha clearly competed less effectively than did untreated cells for lysis of untreated target cells. These results demonstrate that target cells pretreated with PDBu and IFN-alpha decrease their sensitivity to natural killer and lymphokine-activated killer cells inversely with target cell class I HLA antigen expression.

Cell Line↗

PubMed1991

CD4+CD45RA+ cells (suppressor-inducer T cells) in thyroid tissue from patients with Graves' disease.

Previously, we used dual immunofluorescent analysis and showed that the thyroid gland from patients with Graves' disease had a reduced number of CD4+CD45RA+ cells, but an increased number of complementary CD4+CDw29+ cells. An immunohistochemical study, however, produced opposite results; interstitial lymphocytes predominantly expressed the CD45RA+ rather than the CDw29+ phenotype. Because the difference in findings may be due to differences in the techniques used, we did the following experiments: Mononuclear cells were treated with various amounts of collagenase (50-1000 mg/l) which had no effect on the cell surface antigens CD3, CD4 and CD45RA. A dual immunofluorescent study showed that the numbers of CD4+CD45RA+ and CD8+CD45RA+ cell population among CD45RA+ cell population were markedly decreased in the thyroid tissue, and that the CD45RA antigen on the intrathyroidal mononuclear cells was mainly expressed on the CD20+ cells. As the thyroid section had been fixed with acetone before immunohistochemical staining, CD45RA- cells were treated with acetone and stained with anti-CD45RA monoclonal antibody using an avidin-biotin peroxidase complex method. The results of this experiment suggest that there are cell surface molecules which react with anti-CD45RA monoclonal antibody after treatment with acetone in CD45RA- cells. The above findings confirm our previous results which showed that the thyroid glands of patients with Graves' disease have decreased numbers of suppressor-inducer T cells. Also, several problems exist in the detection of CD45RA+ cells when using an immunohistochemical method.

Acetone↗

PubMed1990

Clonal analysis of a human antibody response. Quantitation of precursors of antibody-producing cells and generation and characterization of monoclonal IgM, IgG, and IgA to rabies virus.

We quantitated and characterized the changes in the human B cell repertoire, at the clonal level, before and after immunization with rabies virus. Moreover, we generated 10 monoclonal cell lines producing IgM, IgG, and IgA antibodies to the virus. We found that in healthy subjects, not previously exposed to the virus, nearly 2% of the circulating B lymphocytes were committed to the production of antibodies that bound the virus. These B cells expressed the surface CD5 molecule. The antibodies they produced were polyreactive IgM that displayed a relatively low affinity for the virus components (Kd, 1.0-2.4 x 10(-6) g/microliters). After immunization, different anti-virus (IgG and IgA) antibody-producing cells consistently appeared in the circulation and increased from less than 0.005% to greater than 10% of the total B cells committed to the production of IgG and IgA, respectively. Most of such B cells do not express CD5 and produce monoreactive antibodies of high affinity for rabies virus (Kd, 6.5 x 10(-9) to 1.2 x 10(-10) g/microliters). One of these IgG mAbs efficiently neutralized rabies virus in vitro and in vivo, as detailed elsewhere (Dietzschold, B., P. Casali, Y. Ueki, M. Gore, C. E. Rupprecht, A. L. Notkins, and H. Koprowski, manuscript submitted for publication). Hybridization experiments using probes specific for the different human V gene segment families revealed that cell precursors producing low affinity IgM binding to rabies virus utilized a restricted number of VH gene segments (i.e., only members of the VHIIIb subfamily), whereas cell precursors producing high affinity IgG and IgA to rabies virus utilized an assortment of different VH gene segments (i.e., members of the VHI, VHIII, VHIV, and VHVI families and VHIIIb subfamily). In conclusion, our studies show that EBV transformation in conjunction with limiting dilution technology and somatic cell hybridization techniques are useful methods for quantitating, at the B cell clonal level, the human antibody response to foreign Ags and for generating human mAbs of predetermined specificity and high affinity.

Antibodies, Monoclonal↗

PubMed1990

Cytokine regulation of HLA on thyroid epithelial cells.

The regulation of class I and class II HLA expression in human thyroid follicular cells was studied in vitro. Tumour necrosis factor-alpha (TNF-alpha) enhanced the expression of class I antigen on thyrocytes, but these cytokines had little effect on the expression of class II antigen. Interleukin-1 beta (IL-1 beta) and interleukin-6 (IL-6) did not affect class I and class II antigen expression. The combination of interferon-gamma (IFN-gamma) with TNF-alpha or IL-1 beta enhanced the induction of class I and class II antigens, compared with the effect of IFN-gamma alone. Neither class I nor class II expression was induced by IL-6 alone or in combination with IFN-gamma. These findings suggest that TNF-alpha and IL-1 beta may have an important role in inappropriate expression of HLA antigens on thyrocytes in thyroid gland.

Cell Survival↗

PubMed1990

Biological characterization of human monoclonal antibodies to rabies virus.

Rabies virus antigen-specific human monoclonal antibodies (MAbs) that recognized either viral glycoprotein, ribonucleoprotein, or matrix proteins were generated. Only glycoprotein-specific MAb neutralized a variety of rabies viruses and protected laboratory rodents against lethal rabies virus infection. The determinant recognized by this MAb does not appear to reside in previously defined antigenic sites of the viral glycoprotein.

Animals↗

PubMed1990

Contact dermatitis sparing the eruption of herpes zoster and its periphery.

A 63-year-old male developed allergic contact dermatitis with antibiotic ointment applied to the skin eruptions of herpes zoster. From the result of patch test, fradiomycin sulfate contained in the ointment was identified as the contact sensitizing antigen. Strangely, this contact dermatitis was confined to the area surrounding the sores, sparing the lesions and their periphery. We postulated that a decrease in Langerhans cell activity in the herpes zoster lesions and their peripheral area was primarily responsible for this phenomenon, since an important role of Langerhans cells in host defence against herpes virus infection has recently been demonstrated.

Dermatitis, Contact↗

PubMed1990

Increased accumulation of cytosine arabinoside in human leukemic cells and enhancement of its cell-killing activity by uridine.

The effects of uridine(UR) on the cell-killing activity of cytosine arabinoside(ara-C) against human leukemic cells, MOLT-4, and on ara-C accumulation in cells were studied. The 50% lethal dose(LD50) of ara-C as determined by clonogenic assay was decreased to 5.0 x 10(-8) mol from 9.0 x 10(-7) mol after 3 days exposure to 10(-3) mol of UR. The accumulation of 3H-ara-C at 24 and 48 h was significantly increased in culture medium containing 10(-8) mol of 3H-ara-C and 10(-3) mol of UR (5,129 +/- 123.5 vs 2,554 +/- 115.5 cpm/10(5) cells at 24 h, p less than 0.01, and 5,772 +/- 123.2 vs 1,372 +/- 51.8 cpm/10(5) cells at 48 h, p less than 0.01). It is noteworthy that cell-killing activity of ara-C against human leukemic cells was enhanced by the combination with a nucleoside(UR), but not with antileukemic agents.

Cell Survival↗

PubMed1990

Phenotypic characterization of lymphocytes infiltrating synovial tissue from patients with rheumatoid arthritis: analysis of lymphocytes isolated from minced synovial tissue by dual immunofluorescent staining.

The phenotypic markers of mononuclear cells in synovial tissue from 19 patients with active rheumatoid arthritis (RA) were identified by a dual immunofluorescent method. The mononuclear cells were isolated from synovial tissue by mechanical disaggregation and an enzymatic digestion technique. The results revealed a marked reduction in CD4+2H4+ cells (suppressor inducer T cells) and an increment in CD4+4B4+ cells (helper T cells) among CD4+ cells in synovial tissue. The percentage of CD8+CD11b+ cells (suppressor effector T cells) was significantly lower in synovial tissue than in peripheral blood from patients with RA, resulting in an increased percentage of CD8+CD11b-- cells (cytotoxic T cells). The synovial tissue had higher percentages of pan B cells (B1+ cells), differentiated B cells (B1+B2-- cells) and plasma cells (PCA-1+ cells). These findings suggest that a combination of the increment in helper T cells, the reduction in suppressor T cells, and the increment in differentiated B cells may lead to excessive production of autoantibodies.

Adult↗

PubMed1990

Inhibitory effects of gold sodium thiomalate on the proliferation and interferon-gamma induced HLA-DR expression in human endothelial cells.

Our study was undertaken to investigate the effects of gold sodium thiomalate (GSTM) on the proliferation and HLA-DR antigen expression of human umbilical vein endothelial cells (EC). The proliferation of the EC was determined by 3H-thymidine incorporation into the EC. The expression of HLA-DR antigen on the surface of the EC was detected by an indirect immunofluorescent method using a fluorescent flow cytometer. When GSTM was added at the start of the EC culture, GSTM at a low concentration could inhibit the proliferative response of the EC to endothelial cell growth supplement. Furthermore, when the EC were cultured with recombinant interferon-gamma (rIFN-gamma) and GSTM, GSTM was also able to suppress the HLA-DR antigen expression on the surface of EC induced by rIFN-gamma. On the time-kinetic study of the effects of GSTM on the HLA-DR antigen expression induced by rIFN-gamma, the pretreatment of GSTM was able to suppress the HLA-DR antigen expression, whereas GSTM did not affect the HLA-DR antigen expression already induced by rIFN-gamma. Our findings suggest that the therapeutic effects of gold compounds in patients with rheumatoid arthritis may be attributed to the interference of the proliferation and HLA-DR antigen expression of the EC.

Antigens, Surface↗

PubMed1990

[A case of early gastric carcinoma which disappeared with treatment of low dose 5-FU].

A 60-year-old male with early gastric carcinoma of Ha type, had received colectomy for his carcinoma in transverse colon. He was treated after operation with 5-Fluorouracil (5-FU) orally at 200 mg per day. One and a half month after operation at a total dose 8.4 g 5-FU, the patient was examined on his stomach by endoscope and barium enema. The polypoid tumor in the stomach was not recognized there. No lesion has been noticed in his stomach endoscopically in the following 1 year.

Administration, Oral↗

PubMed1989

Increment in the Ta1+ cells in the peripheral blood and thyroid tissue of patients with Graves' disease.

The present study utilized the anti-Ta1 mAb to characterize the cell surface phenotypes of peripheral blood and intrathyroidal lymphocytes in patients with Graves' disease. We found an increase in PBL bearing the Ta1 Ag in untreated patients. The euthyroid patients in remission, induced by antithyroidal drugs, radioisotope therapy, and subtotal thyroidectomy, had lower percentages of Ta1+ cells than did untreated patients. An increased percentage of Ta1+ cells in untreated patients was found in both CD4+ cells and CD8+ cells. The ratio of CD4+Ta1+ cells to CD8+Ta1+ cells in untreated patients was significantly higher than that of normal subjects. There was a positive correlation between the percentage of Ta1+ cells and the level of anti-TSH receptor antibody. In this prospective study, the proportion of Ta1+ cells was decreased in parallel with the reduction in anti-TSH receptor antibody and free T3 levels. In the chronically treated patients, the proportion of Ta1+ cells in the thyroid tissue was, yet similar to that in the peripheral blood, markedly increased in comparison to that of normal subjects. In contrast to Ta1+ cells, the thyroid tissue had a significantly higher percentage of HLA-DR+ T cells than did the paired peripheral blood. The proliferative responses of the Ta1+ cell-enriched population isolated from untreated patients toward thyroglobulin and microsomal Ag were markedly higher than those in a Ta1+ cell-depleted population, but both populations were able to respond equally to PHA. These results suggest that the Ta1+ cells may include Ag-triggered memory cells that are reactive with thyroid-specific Ag. Furthermore, monitoring such cells may provide an objective measure of abnormal immunologic activity.

Adolescent↗

PubMed1989

Characterization of HTLV-I in a T-cell line established from a patient with myelopathy.

We have established an interleukin 2-dependent, OKT4-positive T-cell line, named HCT-1, from cells in the cerebrospinal fluid obtained from a patient with human T-cell lymphotropic virus type I (HTLV-1)-associated myelopathy. Antigens for HTLV-I were detected in HCT-1 cells by indirect immunofluorescence and Western blot testing, and type C virus particles were detected by electron microscopy. Southern blot analysis of HCT-1 cellular DNA, using an HTLV-I probe, revealed that the integrated provirus genome could not be distinguished from the HTLV-I genome in adult patients with T-cell leukemia.

Blotting, Southern↗

PubMed1989

Cerebral ischemia: changes in monoamines are independent of energy metabolism.

The relationship of neurotransmitters and neuroeffectors to the energy state of the brain was examined in the gerbil model of ischemia after 5 and 15 min of bilateral common carotid artery occlusion only or with 1 hr of reperfusion. The gerbil brains were fixed by microwave irradiation and a total of 15 metabolites were measured from a single piece of tissue from either the hippocampus or the striatum. The rapid alterations in energy-related compounds and cyclic nucleotides appeared to be directly related both to the loss of oxygen and glucose during ischemia and the resupply of these nutrients during reflow. Significant reduction in the level of monoamines occurred principally during reflow, at a time when the energy-related metabolites were restored. It is proposed that the changes in monoamines were triggered by other ischemic-induced events unrelated to energy depletion.

Adenosine Triphosphate↗

PubMed1989

Alignment of protein sequences using the hydrophobic core scores.

Making an alignment of the amino acid sequences is an essential step in the prediction of an unknown protein structure by model building from the known structure of a protein of the same family. To improve the accuracy of the alignments, we introduced the concept of hydrophobic core scores, which restrains putting insertions/deletions in the hydrophobic core regions of the protein. Eight pairs of protein sequences were aligned by this method, and the quality of the alignments were assessed by reference to those obtained by the structural superposition. The introduction of the hydrophobic core scores derived from the knowledge of the tertiary structure of one of each pair resulted in an improvement of the accuracy of the alignments. The quality of the alignment was found to depend on the homology of the protein sequences.

Amino Acid Sequence↗