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Biomedical subjects

Y Maeda

Publications and source records attributed to Y Maeda.

At least 829 records · Page 46Linked to original sources
PubMed1988

Conserved immunogenic region of a major core protein (p24) of human and simian immunodeficiency viruses.

A murine monoclonal antibody (MoAb), VAK 4, has been known to specifically react with a major core protein (p24) as well as with its precursor (p55-57) and intermediate precursor (p40) of human immunodeficiency virus strain IIIB (HTLV-IIIB). Radioimmunoprecipitation assays revealed that VAK 4 MoAb precipitated a major core protein and its precursors from a variety of strains of HIV and also from simian immunodeficiency virus (SIV), although the molecular weights of the precursor proteins in each viral strain were slightly different. A protein synthesized by transfected Escherichia coli containing amino acid sequences corresponding to residues 121-436 of the HTLV-IIIB gag gene was reactive with VAK 4 MoAb, but the protein carrying only residues 121-309 was not reactive, suggesting that the epitope recognized by VAK 4 MoAb resides at the carboxyl terminus of p24 protein. A competitive enzyme-linked immunosorbent assay showed that patient sera containing anticore protein antibody inhibited the binding of VAK 4 to HTLV-IIIB. These findings suggested that VAK 4 MoAb recognized an immunogenic and conserved epitope belonging to a major core protein of HIV-related viruses.

Antigens, Viral↗
PubMed1988

Pulmonary and pleural thymoma. Diagnostic application of lymphocyte markers to the thymoma of unusual site.

Two cases of the thymoma of the unusual sites were examined immunohistochemically. The one was intrapulmonary, and the other was diffuse pleural tumors. The infiltrating lymphocytes were T-cells showing OKT 6 positivity and nuclear immunoreactivity for terminal deoxynucleotidyl transferase (TdT) in the intrapulmonary tumor, like lymphocytes in the mediastinal thymoma of predominantly lymphocytic or mixed types. Although lymphocytes were dispersed in the pleural tumor, there were some TdT(+) OKT 6(-) lymphocytes and the similar finding was observed in the thymoma of predominantly epithelial type. In lung carcinomas and pleural mesotheliomas, there were no TdT(+) OKT 6(+/-) lymphocytes. Immunohistochemical studies using lymphocyte markers may be an useful tool for the diagnosis of the thymoma of ectopic site or unusual presentation.

Aged↗
PubMed1988

A study of the age-related acceleration of glycation of tissue proteins in rats.

The relationship between age-related glycation and a fluorescent product attributable to the advanced Maillard reaction was investigated in the aortas of rats between 4 and 120 weeks of age. The early-stage product of the Maillard reaction was measured using furosine (epsilon-N-(2-furoylmethyl)-L-lysine) as a marker. The advanced product was measured by fluorescence high-performance liquid chromatography. The level of furosine in the aorta increased with aging to reach a maximum value in rats of 50 to 70 weeks of age, and decreased in rats from 90 to 120 weeks of age. By contrast, the level of the putative advanced product reached a maximum in 90-week-old rats and remained at the maximum level in 120-week-old rats. The level of glycated hemoglobin showed no significant change in rats of more than 14 weeks of age. The advanced Maillard products may play an important role in the pathophysiology of aging arteries.

Aging↗
PubMed1988

Lateral forces exerted on the abutment tooth of complete mandibular overdentures.

The purpose of this study was to analyse the magnitude and direction of lateral forces exerted on the abutment tooth of a complete mandibular overdenture. A newly developed transducer was used for measuring forces. It was small enough to be embedded in the lower denture base, and could detect the magnitude and direction of forces. Five subjects, 38 to 77 years of age, with an edentulous maxilla and one or two canines remaining in the mandible were selected for this experiment. An upper complete denture and a lower complete overdenture with only one abutment tooth were fabricated for each subject. Forces exerted on the abutment tooth were measured during tapping and chewing of kamaboko (a Japanese cooked fish paste with soft consistency) and also peanuts, a few days and about 20 days after the denture insertion. The following results were obtained: (i) the average magnitude of lateral forces ranged from 0.5 to 2.0 kgf, and there were significant differences of the mean value between subjects; (ii) lateral forces were mainly observed on an imaginary line drawn through the experimental tooth (lower canine) and the opposite retromolar pad. There were no significant differences between the first and the second measurement.

Adult↗
PubMed1988

Transient increase of the intracellular Ca2+ concentration during chemotactic signal transduction in Dictyostelium discoideum cells.

In general, calcium has been believed to control a variety of cellular processes as a signal transducer, with a high degree of spatial and temporal precision. For the determination of intracellular free-calcium concentrations [( Ca2+]i), the highly selective Ca2+ indicators, quin2/AM and fura2/AM, have been widely used in many mammalian and plant cells. However, intact cells of the cellular slime mold Dictyostelium discoideum Ax-2 are generally impermeable to externally added drugs, thus resulting in a failure to determine [Ca2+]i. Introduction of quin2/AM and fura2/AM by electroporation allowed us to measure [Ca2+]i in D. discoideum cells. The fluorescence images of fura2-loaded single cells showed that resting [Ca2+]i in vegetative and aggregation-competent cells is around 50 nM. Caffeine (10 mM) gave a transient increase in [Ca2+]i, which illustrated a normal responsive ability of electroporated cells to the externally added stimulus. Application of the chemoattractant, cAMP (20 nM), to aggregation-competent cells induced a rapid increase in [Ca2+]i within 1-2 s, and the [Ca2+]i level increased to about four-fold higher than the resting [Ca2+]i within 30 s of chemotactic stimulation. This was followed by a gradual decrease of [Ca2+]i to the basal level. These results strongly suggest that [Ca2+]i is a primary messenger in signal transduction, particularly during the chemotactic response of Dictyostelium cells.

Caffeine↗
PubMed1988

Gonadotropin response to LH-RH in anorexia nervosa and bulimia.

Serum LH and FSH levels before and after stimulation with LH-RH were measured in 9 patients with bulimia, 7 with a restricting subtype and 6 with a bulimic subtype of anorexia nervosa. All patients with anorexia nervosa and 5 (56%) patients with bulimia showed amenorrhea for at least 5 months, while 4 (44%) of the bulimic patients showed oligomenorrhea. Mean basal levels of LH and FSH were low in patients with restricting and bulimic anorexia nervosa, but were normal in patients with bulimia. The response of LH and FSH to LH-RH was impaired in approximately half of the patients with the two subtypes of anorexia nervosa, whereas it was normal in all but one patient with bulimia. These results suggest that bulimic patients with amenorrhea or oligomenorrhea have hypothalamic dysfunctions, which do not appear to be due solely to low weight or to metabolic changes resulting from binge eating, vomiting or purgative use.

Adolescent↗
PubMed1988

Antitumor and other effects of 24R,25-dihydroxycholecalciferol in Lewis lung carcinoma causing abnormal calcium metabolism in tumor-bearing mice.

Lewis lung carcinoma was found to cause hypercalcemia in tumor-bearing mice. 24R,25(OH)2D3 (K-DR, prepared by Kureha Chemical Ind.) significantly prolonged the survival time of mice with Lewis lung carcinoma. K-DR exhibited an antimetastatic effect on Lewis lung carcinoma, and also had an analgesic effect in mice with Lewis lung carcinoma.

Analgesics↗
PubMed1988

Cytotoxic effects of 24R,25-dihydroxycholecalciferol on the proliferation of various tumor cell lines in vitro and its antitumor effects in vivo.

24R,25(OH)2D3, one of the endogenous active metabolites of vitamin D3, showed suppressive effects on the proliferation of various tumor cells in vitro, and showed a suppressive effect on the growth of human osteosarcoma transplanted in nude mice. 24R,25(OH)2D3 increased bone strength lowered by the tumor burden which causes abnormal calcium metabolism and results in hypercalcemia.

Animals↗
PubMed1988

[A case report of primary liver cancer with cerebral metastasis after hepatic resection].

A 67-year-old male, who had a left hepatectomy for hepatocellular carcinoma, was readmitted to our hospital because of a left hemiparesis. A brain computed tomography scan and an r-carotid angiogram revealed a large mass involving the right parietal area, and thus a brain tumor removal was performed. A histological diagnosis of the removed brain tumor found it to be a metastatic, hepatocellular carcinoma. The patient died of pulmonary congestion due to lung metastasis, approximately 2 years and seven months after hepatectomy, and 1 year and three months after the removal of this metastatic brain tumor. In selected cases, the removal of a metastatic brain tumor seems to bring about improvements in the quality and duration of life.

Aged↗
PubMed1988

IL-2 receptor and Fc epsilon R2 gene activation in lymphocyte transformation: possible roles of ATL-derived factor.

Lymphocyte transformation/activation is accompanied by the induction of a variety of the inducible receptors associated with the activation antigens. The p55 chain of the interleukin-2 receptor (IL-2R/p55) recognized by anti-Tac monoclonal antibody (mAb) is expressed on activated T and B cells as well as natural killer (NK) cells. IL-2R/p55(Tac) is constitutively expressed on T4(+) T cells transformed by human T-lymphotropic virus I (HTLV-I), which is a causative agent for adult T-cell leukemia (ATL). Low affinity Fc receptor for IgE (Fc epsilon R2/CD23) is another inducible receptor binding IgE and is expressed on various hematopoietic cell types. While the physiological expression of Fc epsilon R2 and its soluble form (IgE Binding Factor; IgE BF) is variably regulated by cytokines and IgE, there is a constitutive expression of Fc epsilon R2 on Epstein-Barr virus (EBV) transformed B cell lines and some of HTLV-I (+) T cell lines. ATL-derived factor (ADF) has been characterized as an IL-2R/p55(Tac) inducing factor derived from HTLV-I(+) T cell lines. Purification of ADF protein and the cDNA cloning proved that ADF is closely related to the autocrine growth factor produced by an EBV(+) B cell line 3B6 (H. Wakasugi and T. Tursz) and belonging to the family of thiol reducing co-enzyme thioredoxin which is involved in many biological reactions. Recombinant ADF produced by COS cells and E. coli showed both IL-2R inducing and reducing activities. We will discuss the biological roles of ADF in viral and normal lymphocyte activation and transformation in relation to the receptor gene activation.

Amino Acid Sequence↗