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Biomedical subjects

M Kasai

Publications and source records attributed to M Kasai.

At least 307 records · Page 17Linked to original sources
PubMed1992

Survival of mouse morulae vitrified in an ethylene glycol-based solution after exposure to the solution at various temperatures.

Mouse morulae were exposed in one step to a vitrification solution (EFS, a modified PBS containing 40% ethylene glycol, 18% Ficoll, and 0.3-M sucrose) at various temperatures, then cooled rapidly in liquid nitrogen, and then warmed rapidly. All of the embryos exposed to the EFS solution for 0.5 min at 25 degrees C before vitrification developed in culture. However, survival rates were lower if the duration of exposure was prolonged to 2, 5, or 10 min. At lower ambient temperatures (20, 10, and 5 degrees C), high survival rates were associated with longer exposure to the EFS solution. The toxicity of the EFS solution was also lower at lower temperatures. The toxic injury of morulae was manifested as decompaction of the blastomeres. Among the three additives in the EFS solution, ethylene glycol, which can cross cell membranes, was responsible for the toxicity. The results show that the optimum time for exposure of the embryos to the EFS solution before rapid cooling varies with the ambient temperature, i.e., 0.5 min at 25 degrees C, 0.5-5 min at 20 degrees C, 2-5 min at 10 degrees C, and 2-10 min at 5 degrees C. If they are exposed for an optimum period, almost all mouse morulae can survive vitrification (94-100%).

Animals↗
PubMed1992

Aging and immunity.

The function of the immune system peaks at around puberty and gradually declines thereafter with advance in age. The age-related decline of immunological function primarily occurs in the T cell-dependent immune system and is generally associated with increase in susceptibility to infections as well as in incidence of autoimmune phenomena in the elderly. The age-related change in T cell-dependent immune functions can be ascribed to the physiological thymic atrophy which starts in an early stage of life. Emigration of T cells from the thymus to the periphery mainly takes place in the late fetal and newborn stage, and dramatically declines after puberty. In other words, the thymic capacity to promote T cell differentiation starts to change in the early stage of life in terms of quantity and quality of T cells. Thus, the composition of T cell-subsets in the periphery gradually changes with age, resulting in the alteration of T cell functions in the elderly. The restoration of immunological functions of the aged individuals is possible and might be beneficial for them to cope with various diseases associated with aging. Physiological thymic atrophy is controlled by both extrathymic and intrathymic factors, and is not a totally irreversible process. The process of thymic atrophy might be explained by further understanding of the relationship between the neuroendocrine and the immune systems.

Aging↗
PubMed1992

Molecular involvement of the pvt-1 locus in a gamma/delta T-cell leukemia bearing a variant t(8;14)(q24;q11) translocation.

A highly malignant human T-cell receptor (TCR) gamma/delta+ T-cell leukemia was shown to have a productive rearrangement of the TCR delta locus on one chromosome 14 and a novel t(8;14)(q24;q11) rearrangement involving the J delta 1 gene segment on the other chromosome 14. Chromosome walking coupled with pulsed-field gel electrophoretic (PFGE) analysis determined that the TCR J delta 1 gene fragment of the involved chromosome was relocated approximately 280 kb downstream of the c-myc proto-oncogene locus found on chromosome band 8q24. This rearrangement was reminiscent of the Burkitt's lymphoma variants that translocate to a region identified as the pvt-1 locus. Sequence comparison of the breakpoint junctions of interchromosomal rearrangements in T-cell leukemias involving the TCR delta-chain locus revealed novel signal-like sequence motifs, GCAGA(A/T)C and CCCA(C/G)GAC. These sequences were found on chromosome 8 at the 5' flanking site of the breakpoint junction of chromosome 8 in the TCR gamma/delta leukemic cells reported here and also on chromosome 1 in T-cell acute lymphocytic leukemia patients carrying the t(1;14)(p32;q11) rearrangement. These results suggest that (i) during early stages of gamma delta T-cell ontogeny, the region 280 kb 3' of the c-myc proto-oncogene on chromosome 8 is fragile and accessible to the lymphoid recombination machinery and (ii) rearrangements to both 8q24 and 1p32 may be governed by novel sequence motifs and be subject to common enzymatic mechanisms.

Base Sequence↗
PubMed1992

Characterization of the subunits and sugar moiety of human placental and leukemic beta-glucuronidase.

beta-Glucuronidase purified from human placenta and chronic myelogenous leukemic cells was composed of three components of 18, 64 and 80 kDa, though the relative contents of the components were different between the sources. Analysis of their N-terminal amino-acid sequences showed that the 18-kDa and 64-kDa components were derived from the 80-kDa component by cleavage between Val159 and Gly160. Furthermore, the enzyme was found to be glycosylated at Asn173 and Asn420 with high mannose-type oligosaccharides, based on the electrophoretic mobility of the components as well as the endopeptidic peptides before and after endoglycosidase treatment. The enzyme purified from leukemic cells was poorly phosphorylated by N-acetylglucosamine 1-phosphotransferase as compared to the placental enzyme.

Amino Acid Sequence↗
PubMed1992

Cerebellar form of progressive multifocal leukoencephalopathy in a patient with chronic renal failure.

Progressive multifocal leukoencephalopathy (PML) developed in a 64-year-old woman who had undergone hemodialysis treatment due to chronic renal failure (CRF) for 6 yr. Her initial symptom was ataxia, and computed tomographic (CT) scan and magnetic resonance imaging (MRI) suggested a demyelinating disease of the cerebellum. Her cell-mediated immunity was impaired. At autopsy, the cerebellar disease was confirmed as PML by ultrastructural and immunohistochemical studies. Moreover, the JC type of papova virus infection was verified by Southern blot analysis.

Cerebellar Diseases↗
PubMed1992

Useful short-range transport of mouse embryos by means of a nonfreezing technique.

The survival of mouse morulae to be implanted on the uterine wall of a recipient after storage at 0 degree C in sucrose-containing medium has shown tendencies similar to those of blastocysts developing in vitro. The pregnancy rate, as defined by implantation sites per embryos transferred, has varied from 52.9 to 77.2% and decreased depending on the duration of storage (0 to 72 h), and was lower than the rate of blastocyst formation in vitro (57.2 to 87.3%). Regarding the birth rate, 56.0 to 59.4% of implanted embryos were delivered as live pups regardless of storage duration, with the exception of controls (78.9%, 0 h). Eventually, 37.0, 32.8, or 29.9% of embryos were obtained as live pups when preserved by our system for 24, 48, or 72 hours, respectively. This viable, highly reproducible nonfreezing technique is useful for embryo preservation. Embryos were transported to evaluate the efficacy of the nonfreezing method. Mouse morulae were kept in a thermos bottle filled with ice-water and packaged in polystyrene foam. The package was transported from Kochi to Sapporo, about 1300 km, within 48 hours during which it was possible to maintain 0 degree C in the bottle and deliver to most areas in Japan. After shipping, the survival of embryos was 46.8% for development to blastocysts in vitro, and 37.1% for the pregnancy rate, with a final birth rate of 14.1%. Transport factors other than storage may have contributed to the lower birth rate; however, our system is cheaper, more convenient, and more practical than others for short-range transport.

Animals↗
PubMed1992

Reactions of copper(II)-N-polycarboxylate complexes with hydrogen peroxide in the presence of biological reductants: ESR evidence for the formation of hydroxyl radical.

The formation of hydroxyl radicals (.OH) by the reaction of CuII(edta) (edta: ethylenediaminetetraacetic acid) with hydrogen peroxide (H2O2) in the presence of biological reductants, such as L-ascorbic acid and L-cysteine, has been demonstrated for the first time by ESR spectroscopy using water-soluble spin-traps, 5,5-dimethyl-1-pyrroline N-oxide (DMPO, 1), alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone (POBN, 2) and 3,5-dibromo-4-nitrosobenzenesulfonate (DBNBS, 3). Ethylenediaminetetraacetic acid (edta) is one of the polyamine-N-polycarboxylate chelating agents and it is commonly used by chemists and biochemists. Edta can chelate several metal ions. It is known that the CuII(edta) complex is usually less active than free copper ions in radical reactions, whereas complexes of edta with Fe(II) or Fe(III) still react with hydrogen peroxide (H2O2) or superoxide ion (O2-) (1). In our previous papers (2-4), we also have shown that copper(II) complexes with polyamine-N-polycarboxylates, such as edta and dtpa (diethylenetriaminepentaacetic acid), do not react with H2O2, whereas CuII(en)2 (en: ethylenediamine) can easily do so to give hydroxyl radical (.OH) as a reactive intermediate. Further, we assumed that the change of redox potential of Cu(II) ions as a result of ligation with different ligands causes the difference in reactivity of Cu(II) complexes towards H2O2. To verify this assumption, the reactions of CuII(edta), which was chosen as a Cu(II)-polyamine-N-polycarboxylate complex, with H2O2 were investigated in the presence of some biological reductants, using an ESR-spin trapping method.(ABSTRACT TRUNCATED AT 250 WORDS)

Ascorbic Acid↗
PubMed1991

Synergistic effects of interleukin-1 beta and interleukin-3 on the expansion of human hematopoietic progenitor cells in liquid cultures.

In the present study, we show that recombinant human interleukin-1 beta (rhIL-1 beta), which has no effect on the proliferation of human progenitor cells, has synergistic effects on the expansion of human progenitor cells induced by rhIL-3 in liquid cultures. The synergistic effects of rhIL-1 beta with rhIL-3 were observed in liquid cultures using not only fresh bone marrow mononuclear cells, but also selected populations of nonadherent cells, non-T nonadherent cells, and CD34-positive cells. Anti-granulocyte-macrophage colony-stimulating factor (anti-GM-CSF) antibody partially blocked the synergistic effects of rhIL-1 beta on the proliferation of colony-forming unit (CFU)-GM burst-forming unit-erythroid (BFU-E), and CFU-Mix in liquid cultures in the presence of rhIL-1 beta plus rhIL-3, suggesting that the synergistic effects of rhIL-1 beta plus rhIL-3 are explained in part by the secondary production of GM-CSF. Limiting dilution assays and liquid culture assays using CD34-positive cells indicate that rhIL-1 beta directly increases the numbers of colony-forming cells in liquid cultures. These results suggest that rhIL-1 beta has unique direct and indirect effects on the expansion of hematopoietic progenitor cells in liquid cultures.

Antibodies↗
PubMed1991

Production of a monoclonal antibody strongly reacting with immature thymic T lymphocytes and its immunohistological application.

A monoclonal antibody Th-5 has been produced against mouse immature thymic lymphocytes and employed to study the process of T cell differentiation in the thymus. Immunohistologically, Th-5 positive thymic T lymphocytes were first found at Day 12 of gestation. They increased in number as well as staining intensity until Day 18 of gestation and decreased thereafter. Th-5 antigen expression was not seen in lymphoid cells in the fetal liver. In the newborn thymus, lymphocytes in the subcapsular layer were still strongly positive, while other cortical lymphocytes became moderately positive for Th-5. Th-5 positiveness was more pronounced in the medulla than in the cortex in the thymus of young adult mice. The staining pattern of Th-5 in the thymus was apparently different from those with other T cell markers (Thy-1, CD3, CD4, CD5, CD8) including J11d, Pgp-1, IL-2R, and 3A10 (TCR gamma delta). Flow cytometric analyses showed that the expression of Th-5 was mostly associated with the Thy-1 antigen. However, the fluorescent intensity of Th-5 gradually declined with ontogenic development of the thymus, and the molecular size of the antigen was approximately 100 kDa, which is different from Thy-1 antigen (25-30 kDa). Considering these findings, the strong expression of Th-5 could be one of the markers of immature thymic T lymphocytes in the early phase of the ontogenic development.

Animals↗
PubMed1991

Purification of a K(+)-channel protein of sarcoplasmic reticulum by assaying the channel activity in the planar lipid bilayer system.

A K(+)-channel protein of the sarcoplasmic reticulum (SR) was purified by assaying the channel activity in a planar lipid bilayer system. The light fraction of SR vesicles was solubilized in 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS) and fractionated by an anion-exchange chromatography and followed by gel filtration chromatography and affinity chromatography with concanavalin A. All fractions in each steps were mixed with asolectin solubilized in CHAPS and reconstituted into vesicles by dialysis. The channel activity of each fraction was assayed after the reconstituted vesicles had been fused into a planar lipid bilayer. The final fraction which showed the K(+)-channel activity contained only 100 kDa protein in a silver-stained gel after SDS-PAGE and an anti-Ca(2+)-ATPase antibody did not recognize the protein. The characteristics of the K(+)-channel were identical to those observed in native SR vesicles when using the same method. The channel showed a single-channel conductance of 120 pS in 0.1 M KCl and marked voltage dependence. The channel did not permeate Ca2+ and Cl- and was blocked by neomycin B.

Animals↗
PubMed1991

Purification of a Cl-(-)channel protein of sarcoplasmic reticulum by assaying the channel activity in the planar lipid bilayer system.

A Cl- channel protein of sarcoplasmic reticulum (SR) was purified by assaying the channel activity in a planar lipid bilayer system. The light fraction of SR vesicles was solubilized in CHAPS and fractioned by anion exchange, gel filtration, and affinity chromatography with concanavalin A. All fractions in each step were reconstituted into vesicles with asolectin by dialysis and their channel activities were assayed after the vesicles had been fused into a planar lipid bilayer. A 100-kDa protein, different from Ca2(+)-ATPase, was found to form anion channels.

Animals↗
PubMed1991

Structural and functional characterization of inositol 1,4,5-trisphosphate receptor channel from mouse cerebellum.

The cerebellar inositol 1,4,5-trisphosphate (InsP3) receptor is a high molecular weight glycoprotein abundantly expressed in Purkinje cells. The subunit structure of the InsP3 receptor protein was examined by cross-linking experiments. Agarose-polyacrylamide gel electrophoresis of the cross-linked materials demonstrated that the cerebellar InsP3 receptor protein is composed of four noncovalently bound identical subunits each with a Mr of 320,000 in both purified and microsome-bound states. Chromatography of the purified receptor on a calmodulin-Sepharose column demonstrated a Ca2(+)-dependent interaction of the InsP3 receptor with calmodulin. Photoaffinity labeling of the cerebellar microsomal fraction with [alpha-32P]8-azidoadenosine 5'-triphosphate revealed the presence of ATP-binding site in the InsP3 receptor. Scatchard analysis of the purified InsP3 receptor revealed the Bmax and Kd values for ATP binding of 2.3 pmol/micrograms and 17 microM, respectively. Reconstitution of the purified InsP3 receptor into the planar lipid bilayer indicated channel activity in the purified receptor. It exhibited a calcium conductance (26 pS in 53 mM Ca2+) and sodium conductance (21 pS in 100-500 mM asymmetric Na+ solutions) with permeability ratios of PCa/PTris = 6.3 and PNa/PCl = 5.4. The purified channel was activated with submillimolar ATP in the presence of InsP3 and modified to reach a large conductance state.

Affinity Labels↗
PubMed1991

A novel cofactor produced by a thymic epithelial cell line: promotion of proliferation of immature thymic lymphocytes by the presence of interleukin-1 and various mitogens.

Three thymic epithelial cell lines (TEC1C5, TEC1-4, and TEC2-3) were established from the thymus of newborn C57BL/6 mice. TEC1C5 was revealed to be an interleukin (IL)-1 producing cell line. TEC1-4 produced a cofactor to promote proliferation of double negative (CD4-8-) thymic lymphocytes by the presence of IL-1. Production of the same cofactor was also seen in TEC2-3, but only when it was cultured by the presence of indomethacin. The chemical analysis of the TEC1-4 culture supernatant by ion-exchange column and sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that the factor was approximately 35 kDa in molecular weight. The present study revealed that a factor produced by TEC1-4 acted as a cofactor to promote the proliferation of immature T cells stimulated by IL-1 and various mitogens and was considered to be a new one in terms of molecular weight.

Animals↗
PubMed1991

Age influence on the thymic capacity to promote differentiation of T cells: induction of different composition of T cell subsets by aging thymus.

Three kinds of experiments were performed to see the differential effect of aging thymus on T cell differentiation in nude mice and thymectomized mice. In the experiment of thymus grafting into nude mice, the thymic capacity to promote T cell differentiation was the highest at newborn stage, and declined to 80% of the peak level at as early as 1 week of age. The level at 4 weeks of age was 50-60% of the peak level and did not greatly change thereafter with advancing age of thymus donors, up to 24 months of age. However, composition of T cell subsets differed with age of thymus graft; i.e. L3T4(CD4)+ T cells were more easily induced than Lyt-2(CD8)+ T cells by aging thymus, resulting in an increase of the ratio of L3T4+/Lyt-2+ T cells with advancing age of thymus donors. The decreased number of T cells and their subsets in the mice thymectomized at 4 weeks of age could be almost totally recovered by the grafting of newborn thymus, but less efficiently by the grafting of 24-month-old thymus. In the latter case again, L3T4+ T cells were more easily induced than Lyt-2+ T cells, resulting in an increase of the ratio of L3T4+/Lyt-2+ T cells by the grafting of the old thymus. In neonatal mice thymectomized 3 days after the birth, Lyt-2+ T cells were more severely affected than L3T4+ cells, resulting in high ratio of L3T4+/Lyt-2+ T cells. It was suggested that the capacity of the thymus to induce T cells started to decline as early as 1 week of age and did not greatly change between 4 weeks and 24 months of age. However, the composition of T cell subsets induced by the thymus changed with age, with preference for L3T4+ T cells over Lyt-2+ T cells.

Aging↗
PubMed1991

Synthesis and biological evaluation of quinocarcin derivatives: thioalkyl-substituted quinones and hydroquinones.

Varieties of thioalkyl-containing quinone and hydroquinone analogues of quinocarcin (1a) were prepared effectively, by addition of mercaptan to 3a-c, which were derived from 1a via DX-52-1 (1b). Antitumor activities of these analogues were preliminarily evaluated by growth inhibition of HeLa S3 cells (in vitro) and increased life span of P388 implanted mice (in vivo). Bis(alkylthio)quinones 4a-d and 5a-d, and corresponding hydroquinones 9b-d exhibited high activities both in vitro and in vivo. They were superior to 1a especially in single administration. Selected compounds 4a, 4d, 5a, 5d, and 9b were subjected to further evaluation, and bis(methylthio)quinone 5a was revealed to possess broad-spectrum activity toward human xenographted carcinomas MX-1, Co-3, St-4, and LC-06.

Animals↗
PubMed1991

Solubilization and reconstitution of ca pump from corn leaf plasma membrane.

The Ca(2+) transport system of corn (Zea mays) leaf plasma membrane is composed of Ca(2+) pump and Ca(2+)/H(+) antiporter driven by H(+) gradient imposed by a H(+) pump (M Kasai, S Muto [1990] J Membr Biol 114: 133-142). It is necessary for characterization of these Ca(2+) transporters to establish the procedure for their solubilization, isolation, and reconstitution into liposomes. We attempted to solubilize and reconstitute the Ca(2+) pump in the present study. A nonionic detergent octaethyleneglycol monododecyl ether (C(12)E(8)) was the most effective detergent for a series of extraction and functional reconstitution of the Ca(2+) pump among seven detergents examined. This was judged from activities of ATP-dependent (45)Ca(2+) uptake into liposomes reconstituted with the respective detergent-extract of the plasma membrane by the detergent dilution method. C(12)E(8)-extract of the plasma membrane was subjected to high performance liquid chromatography using a DEAE anion exchange column. Ca(2+)-ATPase was separated from VO(4) (3-)-sensitive Mg(2+)-ATPase. These ATPases were separately reconstituted into liposomes, and their ATP-dependent Ca(2+) uptake was measured. The liposomes reconstituted with the Ca(2+)-ATPase, but not with the VO(4) (3-)-sensitive Mg(2+)-ATPase, showed ATP-dependent Ca(2+) uptake. Nigericin-induced pH gradient (acid inside) caused only a little Ca(2+) uptake into liposomes reconstituted with the Ca(2+)-ATPase, suggesting that the Ca(2+)/H(+) antiporter was not present in the preparation. These results indicate that the Ca(2+)-ATPase actually functions as Ca(2+) pump in the corn leaf plasma membrane.

Journal Article↗