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Biomedical subjects

M Taniguchi

Publications and source records attributed to M Taniguchi.

At least 595 records · Page 33Linked to original sources
PubMed1990

Two types of mu chain complexes are expressed during differentiation from pre-B to mature B cells.

Immunoglobulin mu chains synthesized in murine pre-B cells are known to be associated with surrogate light chains designated as omega (omega), iota (iota) and B34. In addition to these molecules, we identified the complexes of polypeptides (50, 40, 27 and 15.5 kd) associated with surface or intracellular mu chains of pre-B cell lines. Most of these polypeptides were continuously synthesized and associated with mu chains in virgin B cells lines, although some of them scarcely bound to the mu kappa dimer or mu 2 kappa 2 tetramer concomitantly present in the same clone or population. However, in mature B cells they were no longer detectable except B34. Cross-linking of micron chains on the surface of pre-B cells resulted in an increase in intracellular free Ca2+, indicating that the micron chain complex on the surface of pre-B cell lines acted as a signal transduction molecule. However, the receptor cross-linkage of pre-B cell lines did not induce the increased inositol phospholipid metabolism usually observed in virgin and mature B cell lines. These results suggest that, during the differentiation from pre-B to mature B cells, the cells express two types of mu chain complexes which exhibit different structures as a whole and possess different signal transducing capacities.

Abelson murine leukemia virus↗
PubMed1990

Properties and repeated use of a reversibly soluble-insoluble yeast lytic enzyme.

A yeast lytic enzyme was covalently immobilized on an enteric coating polymer, Eudragit S, that is reversibly soluble and insoluble (S-IS) depending on the pH of the reaction medium. The yeast lytic enzyme immobilized on Eudragit S (Y-E) showed a sharp response of solubility to slight changes in pH without decrease in enzymatic activity. The specific activity per amount of enzyme protein of Y-E for dry yeast cells was about two-thirds that of the native enzyme. In both lysis reactions of dry and pressed baker's yeast cells, changing the pH of the reaction medium from 7.0 to 4.8 at an appropriate interval allows the insoluble Y-E and the reaction products (soluble protein for dry yeast cells and invertase and soluble protein for pressed baker's yeast cells) to be repeatedly separated. The reaction method using a reversible S-IS enzyme is a promising procedure for repeated use of the enzyme in a heterogeneous reaction system containing yeast cells as a substrate.

Acrylic Resins↗
PubMed1990

Diagnostic values of gallbladder hyperperfusion and the rim sign in radionuclide angiography and hepatobiliary imaging.

The diagnostic values of hyperperfusion to the gallbladder fossa and the rim sign were retrospectively evaluated in 24 histopathologically proven cases of gallbladder disease. Although 12 of 13 patients (92%) with acute cholecystitis had nonvisualization of the gallbladder, the positive predictive value with this finding was 71%. However, when the finding was associated with hyperperfusion to the gallbladder fossa or the rim sign, the positive predictive value with both (90%) was markedly increased, compared to the prevalence ratio of 54%. Such a combination could be useful for preserving a high positive predictive value in the diagnosis of acute cholecystitis.

Acute Disease↗
PubMed1990

Homogenous junctional sequence of the V14+ T-cell antigen receptor alpha chain expanded in unprimed mice.

Nucleotide sequences of VJ (variable-joining) junctional regions of V14+ alpha-chain T-cell receptor genes show that most V alpha 14+ T cells use one alpha chain (V alpha 14J alpha 281 with a one-nucleotide N region, which is frequently used in keyhole limpet hemocyanin-specific suppressor T-cell hybridomas) in unprimed mice. Moreover, the frequency of this alpha-chain expression was greater than 1.5% of the total alpha chains found in laboratory strains, including B10 congenic mice. This is about 10(4) times higher than was expected. The V14J281 alpha-chain expression was relatively low but was significant in CD4+/CD8+ immature thymocytes and became quite high in mature single-positive T cells, implying that this alpha chain is selected during T-cell maturation. V14J281 expression increased with time after birth and reached a maximum at around 5 weeks of age. The ligand seems to be a self molecule and to be present in laboratory strains but to be absent in a wild mouse, Mus musculus molossinus, because bone marrow chimeras clearly showed that bone marrow cells derived from Mus musculus molossinus negative for this alpha chain raised V14J281-positive T cells in a C57BL/6 environment. The above results suggest that there are some selection mechanisms for this cell type other than those for conventional alpha beta T cells and also that the homogenous VJ junction of the V14J281 alpha chain plays a pivotal role in the selection of the T cell and its ligand reactivity.

Animals↗
PubMed1990

Ontogenic changes in hepatic glutathione and metallothionein in rats and the effect of a low-sulphur-containing diet.

Metallothionein contains about 30% cysteine and is a major protein in newborn rat liver. This protein and glutathione constitute two major intracellular cysteine pools in newborn rat liver. When pregnant rats were fed on a soya-bean-protein diet, low in sulphur amino acids, the hepatic glutathione levels of the dams were decreased. However, this did not affect the levels of glutathione or metallothionein in the pups. The activity of the glutathione-degrading enzyme gamma-glutamyltransferase (EC 2.3.2.2) in the livers of pups was maximum at birth and gradually decreased with age when the hepatic glutathione was transported to the kidney. In the pups born from dams fed on soya-bean-protein diet the decline in the hepatic enzyme activity was delayed, suggesting a continued degradation of glutathione in the liver. These results suggest that even with a maternal nutritional deficiency of sulphur amino acids, the transfer of cysteine to the fetus is not impaired. However, the hepatic intra-organ degradation of glutathione is continued in these pups for a prolonged period after birth compared with pups born from control mothers. The increased degradation of glutathione in the liver may be essential to meet the requirement of cysteine in pups born from dams fed on the soya-bean-protein diet.

Aging↗
PubMed1990

Establishment of human monoclonal antibody recognizing a new tumor-associated antigen from a patient with small cell lung carcinoma.

Mouse-human heterohybridoma (3H12) producing human antibody was established by fusing P3/X63-Ag-U1 (P3U1) myeloma cells with lymphocytes from a patient of small cell lung carcinoma (SCLC). This monoclonal antibody reacts to lung cancer cells, especially SCLC, but not to adenocarcinoma or squamous cell carcinoma cells. It does not show any reactivities to other tumors or normal cells so far examined. An immunoprecipitation experiment with this antibody revealed that the antigen on SCLC was a single chain moiety of 150 kilodaltons (Kd). Judging from the cell type reactivity and molecular size of the antigen, this monoclonal antibody appears to detect a new tumor-associated antigen on human SCLC.

Animals↗
PubMed1990

"Alternative self-diploidization" or "ASD" homothallism in Saccharomyces cerevisiae: isolation of a mutant, nuclear-cytoplasmic interaction and endomitotic diploidization.

A mutant of Saccharomyces cerevisiae representing a novel life cycle, named "alternative self-diploidization" or "ASD" homothallism, was obtained fortuitously. In this life cycle, MAT alpha (or MATa) haplophase and MAT alpha/MAT alpha (or MATa/MATa) diplophase alternate. Germinated cells are haploid and mating. They soon become nonmating and sporogenous as they vegetatively grow. They sooner or later diploidize presumably via endomitosis. The diploid cells haploidize via normal meiosis. A single recessive nuclear mutation, named asd 1-1, is responsible for "ASD" homothallism. In the rho 0 cytoplasm, asd 1-1 cells mate even if at a low efficiency and fail to diploidize. Since pet mutations do not have such effects, we conclude that a certain mitochondrial function other than respiration is required for manifestation of "ASD" homothallism. That is, "ASD" homothallism is the result of some sort of nuclear-cytoplasmic interaction.

Cell Nucleus↗
PubMed1990

Surgical and electrophysiological observations during clipping of 134 aneurysms with evoked potential monitoring.

Somatosensory evoked potentials (SEPs) were monitored during 113 operations for the clipping of 134 cerebral aneurysms. Changes in peak latency and amplitude of early cortical SEP as well as central conduction time were evaluated. In 58 cases surgical occlusion of arterial vessels or other events occurred, and in 17 of these cases such events were associated with SEP changes or loss. Arterial occlusions resulted from temporary clipping of a feeding blood vessel (22), accidental clipping of a vessel (12), and intentional permanent vessel occlusion (8). A total SEP loss was seen in 2 cases of accidental vessel occlusion and in 6 cases of temporary vessel clipping. Significant SEP changes were found in 6 patients with temporary clipping, and once each with retraction of the cerebellum, retraction of the middle cerebral artery, and after intentional permanent vessel occlusion. Response to these changes included reapplication of aneurysm clips, repositioning of retractors, or removal of temporary clips. Stable SEP signals during 13 cases allowed the surgeon to proceed with the surgical course. Despite the limitations of SEP monitoring in certain anatomical locations, it has been found to be helpful in the operative management of some cases such as multilobed aneurysms of the middle cerebral artery, giant aneurysms, trapping procedures, and procedures requiring temporary vessel occlusion.

Adolescent↗
PubMed1990

Estimation of right ventricular pressure by 201Tl scintigraphy in paediatric cardiac disease.

To estimate right ventricular overload in paediatric cardiac disease, 201Tl scintigraphy was used to quantify right ventricular uptake. Six methods for calculating the 201Tl right-to-left ventricular uptake ratio (TRL) were compared, based on the location of regions of interest (ROIs), use of total count or mean count density, and the ROI-based method or profile method. When the TRL was compared with the right-to-left ventricular peak systolic pressure ratio (RVP/LVP), the mean count density method using entire right and left ventricular ROIs seemed to be appropriate, considering its simplicity, reproducibility and regression line. The linear regression line was RVP/LVP = 1.15 x TRL - 0.13 (n = 15, P = -0.0001), and RVP(mm Hg) = 162 x TRL - 33 (n = 15, P = 0.0001). In four patients with pulmonary stenosis, the changes of TRL were in good agreement with the right ventricular pressure changes after percutaneous balloon valvuloplasty. Thus, evaluation of thallium scintigraphy using this quantitative method can be a simple and effective way to evaluate patients with right ventricular pressure overloading.

Adolescent↗
PubMed1990

Induction of mouse anti-melanoma cytotoxic and suppressor T cells in vitro by an artificial antigen, GM3-lactone.

We investigated the ability of GM3-lactone liposomes to induce anti-melanoma T cell responses in mice. GM3-lactone liposomes, like murine B16 melanoma cells, induced anti-melanoma cytotoxic T cells (CTL) and also suppressor T cells (Ts). A small dose of GM3-lactone (0.0003 micrograms/ml) was enough to generate CTL in the in vitro primary response, whereas relatively large amounts of the antigen (0.03-0.3 microgram/ml) were required for anti-melanoma Ts induction. As the epitope for anti-melanoma Ts is NeuAc but not NeuGc residue on GM3, and anti-melanoma CTL are effectively induced by either GM3(NeuAc) or GM3(NeuGc)-lactone liposomes, GM3(NeuGc)-lactone or GM3(NeuGc) liposomes have potent activity as an artificial melanoma antigen to induce anti-melanoma CTL in vitro.

Animals↗
PubMed1990

Expression of IgH promoter/enhancer Ly-1 transgene in hematopoietic chimeric mice generated by embryonic stem cell line.

We have produced hematopoietic chimeric mice from an embryonic stem (ES) cell line carring Ly-1 cDNA under the control of IgH promoter and enhancer. Various amounts of serum IgM (5-86% of total IgM) in chimeric mice were of ES origin and 30-60% of IgM-positive B cells from the chimeric mice analyzed were reconstituted from ES cells. Using these chimeric mice, the expression of the Ly-1 transgene on lymphoid tissues was examined by polymerase chain reaction assay with primers specific for the transgene, and by cell sorter analysis. Transcription of the Ly-1 transgene was detected in spleen cells, thymocytes and lymph node cells; however, the expression of the Ly-1 molecule was observed only on lipopolysaccharide (LPS)-stimulated splenic IgM-positive B cells but not on resting splenic B cells. There was no significantly increased expression of Ly-1 on splenic T cells and thymocytes. Thus, our findings demonstrate that conventional splenic B cells could express the Ly-1 transgene on their surface in vivo after LPS stimulation. Also discussed is the ES-derived chimeric hematopoietic system.

Animals↗
PubMed1990

Effects of gangliosides on cell maturation of murine megakaryocytes in a liquid culture system.

Formation of platelet-producing megakaryocytes, the cytoplasm of which showed the terminal stage of cell maturation, heavy granulation and platelet-fields delineated with demarcation membranes, was observed in a short-term culture system, using megakaryocyte-enriched bone marrow cell suspension. Approximately 6-8% of the megakaryocytes changed to the platelet-producing megakaryocytes during 12-hour incubation. In the presence of inhibitors of energy metabolism, formation of the platelet-producing megakaryocytes was inhibited, suggesting that the process is dependent on energy producing systems. Ganglioside GD1a increased both the number of total megakaryocytes and the ratio of the platelet-producing megakaryocytes to total megakaryocytes, while GM1 did not influence the number of total megakaryocytes, but increased the ratio. Gangliosides GM2, GM3 and GD1b showed little effect on either the number of total megakaryocytes or the ratio. The results suggest that ganglioside GD1a stimulates at least two steps of megakaryocyte maturation, the change of megakaryocytic progenitors to megakaryocytes and the subsequent maturation of megakaryocytes to the platelet-producing megakaryocytes, while GM1 stimulates only the latter step of the maturation.

Animals↗