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Biomedical subjects

A Yamaguchi

Publications and source records attributed to A Yamaguchi.

At least 649 records · Page 36Linked to original sources
PubMed1988

[A case of early gastric cancer forming a large abdominal tumor from a lymph node metastasis].

A 37-year-old male was admitted to our hospital because of an abdominal tumor, about the size of a fist, located anterior to the pancreas head. This tumor oppressed the antrum of the stomach to the left, and an operation was performed, the tumor being diagnosed as a leiomyosarcoma of the stomach, determined from image findings. After histopathological examination, however the tumor proved to be an adenocarcinoma. An early gastric cancer was found at the anterior wall of the antrum during the operation, and the tumor was thought to be a metastatic lymph node. Lymph node metastasis also was observed at the root of the mesentery.

Adenocarcinoma↗
PubMed1988

Mechanisms of transplantation tolerance induced by liver grafting in rats: involvement of serum factors in clonal deletion.

An adoptive transfer assay system was used to investigate the ability of serum from tolerant, liver-grafted rats to inactivate normal thoracic duct lymphocytes. PVG rats were rendered tolerant of DA alloantigens by liver grafting. Serum taken from such rats was used to treat normal PVG thoracic duct lymphocytes (TDL) in vitro and the transplant reactivity of the cells then tested in an adoptive transfer assay. Specific decreased responsiveness compared with TDL treated with normal sera was observed, indicating the functional elimination of alloreactive clones by agents in liver-graft serum.

Animals↗
PubMed1988

[Combination chemotherapy with adriamycin, cyclophosphamide, vincristine, prednisolone (VEPA) in non-Hodgkin's lymphoma, with special reference to correlation of surface phenotype with response and survival].

Thirty-seven previously untreated patients with advanced non-Hodgkin's lymphoma were treated with VEPA therapy. The complete remission (CR) rate was higher in the patients with diffuse B-cell lymphoma (75%) than in those with follicular B-cell lymphoma (20%) and T-cell lymphoma (42%). Two characteristics, i.e., elevated LDH and bone marrow involvement, were negatively associated with response rate in patients with diffuse lymphoma (B-, T-). The median duration of CR has not yet been reached, and the 2-year relapse-free rate was 64% for cases of diffuse B-cell lymphoma, while for T-cell lymphoma patients, the median duration of CR was 7 months. For diffuse B-cell lymphoma patients, the median survival has not yet been reached, and the 2-year survival rate was 57%. On the other hand, median survival for T-cell lymphoma patients was 12 months. VEPA therapy was less effective for the treatment of T-cell lymphoma, and a more intensive regimen should therefore be designed to overcome the potential aggressiveness of T-cell lymphoma.

Adult↗
PubMed1987

Ca2+ influx mediated through the GPIIb/IIIa complex during platelet activation.

When aequorin-loaded platelets were stimulated with thrombin, the luminescence signal of aequorin showed two peaks. From experiments with 1 mM external Ca2+ or EGTA, both one-half of the first peak and the entire second peak reflected the influx of Ca2+ from the external medium, and the remaining half of the first peak reflected the mobilization of Ca2+ from its storage site. A monoclonal antibody (TM83) that recognizes the glycoprotein IIb/IIIa (GPIIb/IIIa) complex which has binding sites for fibrinogen and the synthetic peptide GRGDSP are known to inhibit fibrinogen binding and platelet aggregation. Both eliminated the second peak of intracellular free calcium ([Ca2+]i). Similar effects were observed during activation by collagen, but not during PMA activation. It was concluded that the GPIIb/IIIa complex was intimately related to a part of the Ca2+ influx during the activation of platelets.

Aequorin↗
PubMed1987

A new variant of thrombasthenia with abnormally glycosylated GP IIb/IIIa.

A 15 year-aged Japanese girl with a life long mild purpura was found as a variant type of thrombasthenia. Basic tests revealed prolonged bleeding time, border-line clot retraction, no coagulation defect, no giant platelets and mild thrombocytopenia (70,000-110,000/microliters). Neither ADP, epinephrine nor collagen aggregated her platelet rich plasma. Thrombin (0.1U/ml) caused slightly decreased aggregation of her washed platelets and about 20% normal production of thromboxane B2. PAS-stained SDS-PAGE of her whole platelets showed markedly decreased GP IIb and IIIa. However, crossed immunoelectrophoresis (CIE) against anti-whole platelets antibody showed a normal amount of GP IIb/IIIa complex in her whole platelets solubilized with 1% Triton X-100. CIE using monospecific anti-GP IIb/IIIa complex antibody showed normal dissociation of the patient's GP IIb/IIIa complex into two new bands in the presence of EDTA. Crossed affino-immunoelectrophoresis with the first dimension containing Concanavalin A revealed that the patient's GP IIb/IIIa was much less shifted to the cathode than controls. Immunoprecipitation lines of her GP IIb/IIIa complex were excised from unstained CIE using anti-GP IIb/IIIa antibody and subjected to the silver-stained reduced SDS-PAGE, which showed two protein bands with molecular weights of 125KD and 108KD, corresponding to GP IIb alpha and GP IIIa, respectively. These results suggest that the platelets of this apparently thrombasthenic patient have an antigenically normal but abnormally glycosylated GP IIb/IIIa complex, which is functionally abnormal because of abnormal glycosylation.

Adolescent↗
PubMed1987

Identification of the active site of Citrobacter freundii beta-lactamase using dansyl-penicillin.

The active site sequence of a beta-lactamase encoded by chromosomal gene(s) in Citrobacter freundii GN346 was determined using dansyl-penicillin as a fluorescent probe. The tryptic digest of the labelled enzyme gave a fluorescent peptide containing 22 amino acids. The sequence of this peptide was identical to the consensus sequence of class C beta-lactamases, Gly-Ser-X-Ser-Lys. The residue labelled was the serine adjacent to the glycine. The active site sequence corresponded to positions 46-67 of the entire sequence of the Citrobacter freundii beta-lactamase determined on the basis of the DNA sequence of the structural gene [(1986) Eur. J. Biochem. 156, 441-445]. The labelled serine corresponded to Ser-64.

Amino Acid Sequence↗
PubMed1987

Glucose stimulates insulin release without altering cyclic AMP production or inositolphospholipid turnover in freshly obtained human insulinoma cells.

Glucose, forskolin, IBMX and carbachol all stimulated insulin release from freshly obtained human insulinoma cells. In these same cells, cellular cyclic AMP levels were raised by forskolin and IBMX but not by glucose and carbachol. On the other hand, of all the insulin secretagogues examined, only carbachol stimulated the formation of 3H-inositol trisphosphate in these cells. Thus, in these insulinoma cells, glucose apparently induces insulin secretion without altering cyclic AMP production or inositolphospholipid turnover.

1-Methyl-3-isobutylxanthine↗
PubMed1987

Radiation-induced occlusion of the artery in the distal lower extremity--a case report.

In a 54 year-old man, a symptomatic occlusion of the popliteal artery and its trifurcation occurred following radiotherapy. Three years following curative radiotherapy to the upper tibia for metastatic renal cell carcinoma, he began experiencing intermittent claudication of the calf, which suddenly progressed to severe rest pain and coldness of the foot, and eventually to ischemic ulcer. Angiogram revealed an atherosclerotic occlusion well localized within the field of the previous irradiation. The significance of this rare entity is discussed from various aspects.

Arterial Occlusive Diseases↗
PubMed1987

Serum valproate concentrations in epileptic children with favourable responses.

The lower limits of the "therapeutic range" for serum levels of sodium valproate (VPA) were evaluated in epileptic children showing a benign clinical course. Twenty-five outpatients, aged 5 to 16 years, whose seizures were well controlled over three years with VPA alone, were studied. Venous blood was taken 1.1 to 5 hrs after the morning dose. Serum VPA concentrations at steady-state after receiving the maintenance doses to control seizures were determined by enzyme immunoassay. The patients were divided into three groups according to the seizure type and the age at onset; A and B: patients with tonic and/or clonic seizures, aged below 3 yrs (n = 11) and 3 to 11 yrs (n = 6), respectively, C: those with absence seizures, aged 4 to 11 yrs (n = 8). The serum concentrations in A (47.8 +/- 21.6 micrograms/ml, mean +/- SD) were significantly (p less than 0.02) lower than those in groups B and C (85.2 +/- 14.0 and 73.0 +/- 17.4 micrograms/ml, respectively). VPA concentrations below 50 micrograms/ml were seen in 6 patients (55%) in group A. It was concluded that many epileptic children, whose ages at onset were below 3 yrs, with tonic and/or clonic seizures could be controlled even with low initial serum concentrations below the "therapeutic range".

Adolescent↗
PubMed1987

Characterization of rat T cell subset antigen by monoclonal antibody.

6B2-B8 T cell hybridoma cells were used to immunize mice, and immune spleen cells were fused with NS/1 myeloma cells. One clone, designated RTH-7, reacted with 89.5% of rat thymocytes, 30.2% of rat spleen cells, and 42.3% of rat lymph node cells. The RTH-7 reacted with a subset of rat T cells but not with B cells. Double staining analysis demonstrated that RTH-7 stained a rat T cell subset distinct from R1-10B5-positive cells that were known to be equivalent to mouse Lyt-2. It was revealed that RTH-7 and W3/25 recognize different antigenic epitopes on the same molecule. The RTH-7 as well as W3/25 substantially inhibited the production of interleukin 2 by cells in mixed lymphocyte reaction and the lymphocyte proliferation induced by mixed lymphocyte reaction. The RTH-7 inhibited the lymphocyte proliferation induced by Con A whereas W3/25 failed to do so. The RTH-7 defined antigen has a molecular weight of 53,000 under reducing condition and 47,000 under nonreducing condition. The RTH-7 defined antigen showed a wide range of heterogeneity in pI (6.2-8.8). The associated molecule of approximate molecular weight of 27,000 was occasionally detected with the RTH-7 defined antigen in 6B2-B8 T cell hybridoma cells as well as peripheral T cells but not in thymocytes. Thus, RTH-7 detects a cell surface antigen of a functional T cell subset of rat origin.

Animals↗