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S Kondo

Publications and source records attributed to S Kondo.

At least 721 records · Page 40Linked to original sources
PubMed1993

Transforming growth factor-beta 1 enhances the generation of allospecific cytotoxic T lymphocytes.

We investigated the effects of transforming growth factor-beta 1 (TGF-beta 1) on the proliferation and generation of murine T lymphocytes in vitro. TGF-beta 1 suppressed T- and B-lymphocyte proliferation, mixed lymphocyte reaction (MLR), and the generation of natural killer (NK) cells and lymphokine-activated killer (LAK) cells. On the other hand, TGF-beta 1 significantly enhanced the generation of allospecific cytotoxic T lymphocytes (CTL) at low concentrations (0.01-1 ng/ml) in a dose-dependent manner and restored it to the control level at higher concentrations (10-40 ng/ml). Allospecific CTL generation by TGF-beta 1 was maximally enhanced when added at the beginning of culture. Less enhancement occurred when the addition was delayed. Anti-TGF-beta 1 antibody completely abolished the enhancing effects of TGF-beta 1. Furthermore, platelet-derived TGF-beta (pTGF-beta) as well as recombinant TGF-beta 1 similarly enhanced the generation of allospecific CTL. These data demonstrate that TGF-beta has not only immunosuppressive effects but also immuno-enhancing effects in vitro.

Animals↗
PubMed1993

Application of corrosion cast method for scanning electron microscopic observation of mouse embryo vasculature.

We described a method for making vascular corrosion casts of mouse embryos and applied it to study the vasculature of the whole body mouse embryo at 13.5 days (body length 9-11 mm) to 18.5 days (body length 18-23 mm), as well as that of its respective organs. The Mercox resin was perfused via the umbilical vessels using a special needle made by pulling the hematocrit tube (caliber 100-200 microns). The specimens were treated with 10% NaOH, rinsed, dried, coated with gold and observed under a scanning electron microscope. Visceral organs of a 13.5 day embryo were rather immature, but the liver vasculature was relatively well developed. In a 15.5 day embryo, the whole body vasculature was relatively well developed and the features of respective organs could be identified. In a 18.5 day embryo, almost all organs and extremities were well developed, but sensory organs in some parts showed immature development.

Animals↗
PubMed1992

Efficient amplification of Drosophila simulans copia directed by high-level reverse transcriptase activity associated with copia virus-like particles.

The number of retrotransposon copia per genome in Drosophila melanogaster cultured cells is two to three times higher than that in D. melanogaster embryo cells. Here, we have found that the genome of the related species, Drosophila simulans, contains in cultured cells more efficiently amplified copia DNA (approximately ten fold). Furthermore, we analyzed copia virus-like particles (VLPs) prepared from D. melanogaster and D. simulans cultured cells, which contain copia RNA and reverse transcriptase (RT) activity, and thus, play a major role in copia replication. The RT activity associated with the D. simulans VLPs was 25 times higher than that associated with the D. melanogaster VLPs. Taken together with the fact that copia is believed to transpose through an RNA intermediate, these results suggest that the amplification of copia DNA should relate to copia RNA-mediated transposition, and the higher RT activity associated with the D. simulans VLPs would lead to the efficient amplification of copia DNA. In a comparison between D. melanogaster and D. simulans copia nucleotide (nt) sequences, five nt substitutions, which cause the respective amino acid changes, were found in the copia RT-coding region. Polymerase chain reaction direct sequencing showed that these five substitutions are the vast majority in each Drosophila species. The substitutions, therefore, may be responsible for the high level of the RT activity associated with the D. simulans VLPs.

Amino Acid Sequence↗
PubMed1992

Taxonomic implication of the apparent undetectability of 3-deoxy-D-manno-2-octulosonate (Kdo) in lipopolysaccharides of the representatives of the family Vibrionaceae and the occurrence of Kdo 4-phosphate in their inner-core regions.

After conventional hydrolysis of lipopolysaccharides (LPSs), Kdo was not detectable by the periodate-thiobarbituric acid test in those of any member of Vibrionaceae except the gems Plesiomonas, but phosphorylated Kdo was demonstrated after strong-acid hydrolysis. Dephosphorylation, periodate oxidation, and methylation analysis of LPS preparations from 7 strains selected from all genera of Vibrionaceae, except Plesiomonas, showed that the inner-core region (unlike that in enteric Gram-negative bacteria) contains only one molecule of Kdo 4-phosphate 5-substituted with heptose, a constituent of the distal part of the core region, as in enteric bacteria. The undetectability of Kdo in LPS after conventional hydrolysis and the occurrence of phosphorylated Kdo in strong-acid hydrolysates and of Kdo 4-phosphate in the inner-core region are taxonomic characteristics of the family Vibrionaceae.

Hydrolysis↗
PubMed1992

Neurotransmitter release from synaptotagmin-deficient clonal variants of PC12 cells.

Synaptotagmin (p65) is an abundant synaptic vesicle protein of neurons and contains regions similar to the regulatory domain of protein kinase C. These domains are thought to be involved in calcium-dependent interaction with membrane phospholipids during exocytosis. To assess the functional role of synaptotagmin, synaptotagmin-deficient clonal variants of PC12 cells were isolated. All of the variant cells released catecholamine and adenosine triphosphate in response to elevated intracellular concentrations of calcium, which suggests that synaptotagmin is not essential for secretion of catecholamine and adenosine triphosphate from PC12 cells.

Adenosine Triphosphate↗
PubMed1992

Granulocyte colony-stimulating factor receptors on human acute leukemia: biphenotypic leukemic cells possess granulocyte colony-stimulating factor receptors.

Granulocyte colony-stimulating factor (G-CSF) receptors on the gated leukemic blast cells from newly diagnosed patients with acute leukemia or crisis of chronic myelogenous leukemia were investigated using flow cytometric detection. Surface marker analysis and cytochemical studies were conducted simultaneously to characterize the blast cells. Among 24 leukemia cases examined, G-CSF receptor-positive blast cells were detected in all 11 cases of acute myeloblastic leukemia even though the percentage range of positive cells was widely variable. On the other hand, they were not detected on the blast cells from patients with peroxidase-negative acute lymphoblastic leukemia with no myeloid surface antigens. However, G-CSF receptors were demonstrated in significant amounts on blast cells from 5 of 8 cases of peroxidase-negative acute leukemia expressing both myeloid and lymphoid surface antigens (biphenotypic leukemia). The percentage of blast cells positive for G-CSF receptors was significantly smaller in biphenotypic cases [33 +/- 14% (SD)] than in acute myeloblastic leukemia cases [65 +/- 22%] (P less than 0.01). The percentage expression of CD13 antigen by blast cells was significantly related to their percentage positivity for G-CSF receptors (rs = 0.50, P less than 0.05). These findings indicate that the distribution of flow cytometrically detectable G-CSF receptors on leukemic cells possessing myeloid characteristics may be related to the maturation process.

Antigens, CD↗
PubMed1992

Production of a unique multi-lamella structure in the nuclei of yeast expressing Drosophila copia gag precursor.

Drosophila retrotransposon copia produces virus-like particles (VLPs) in the nuclei of cultured Drosophila cells. The VLPs contain copia RNA and reverse transcriptase activity, and thus, play a major role in copia replication. Here we have expressed the copia gag polyprotein precursor in yeast. The precursor, which includes copia protease itself, showed correct autoprocessing to produce a unique multi-lamella structure in the nuclei of the yeast cells. This expression system should be useful for the analysis of nuclear localization of the major copia VLP protein, and furthermore, would provide important information concerning the mechanism of copia VLPs formation.

Animals↗
PubMed1992

Analysis of the close relationship between human astrocytoma-specific antigens detected by murine monoclonal antibodies and c-kit proto-oncogene product.

Tyrosine-specific phosphorylated proteins found exclusively on the cell surface of human astrocytomas were previously identified with murine monoclonal antibodies, designated as GA-17, GB-4 and GC-3. The purpose of this study was to further characterize the antigens and investigate the relationship between them and c-kit protooncogene product. We demonstrated that the antigens had protein kinase activity. Moreover, GA-17 reacted with c-kit protein expressed on the membrane of A172 human glioblastoma cells.

Antibodies, Monoclonal↗
PubMed1992

Folinic acid does not mobilize hemopoietic progenitors following repeated consolidation chemotherapy for acute leukemia.

Folinic acid (FA) has been reported to expand the pool of peripheral blood stem cells (PBSC) after chemotherapy. We evaluated the efficacy of FA for harvesting PBSC following cytotoxic chemotherapy in 4 patients with acute leukemia. After achieving a complete remission (CR), 3 courses of chemotherapy for a consolidation of the CR were administered to the patients. Two successive cycles of leukapheresis were performed during the recovery phase from consolidation chemotherapy, which consisted of an intermediate dose of cytosine arabinoside. For the second cycle of leukapheresis, FA was administered intravenously at a dose of 50 mg/day following consolidation. The yields of either mononuclear cells or burst-forming units-erythroid (BFU-E) were not affected by FA administration. In contrast, the yields of colony-forming units-granulocyte/macrophage (CFU-GM) were significantly decreased in all patients compared to the CFU-GM yields after the first cycle of leukapheresis (P = 0.032). Thus FA is considered not to be effective in expanding the peripheral blood progenitor pool when given in a fashion different from the original report.

Acute Disease↗
PubMed1992

Restoration of proliferating cell nuclear antigen (PCNA) complex formation in xeroderma pigmentosum group A cells following cis-diamminedichloroplatinum (II)-treatment by cell fusion with normal cells.

We examined the role of the factor deficient in xeroderma pigmentosum group A (XP-A) cells in the formation of proliferating cell nuclear antigen (PCNA) complex with DNA in the DNA repair process in human fibroblasts following cis-diamminedichloroplatinum (CDDP)-treatment. Immunofluorescence staining after methanol fixation was used to detect the PCNA complex formation. When quiescent normal cells were PCNA-stained at 3 h after 100 microM CDDP treatment for 1 h, almost all nuclei of the cells showed a punctuated staining pattern. On the other hand, nuclei of XP-A cells were not stained. These results were the same with the findings following 10J/m2 of ultraviolet light (UV)-irradiation. The quantitative analysis of the PCNA immunofluorescence intensity of normal cells revealed that the mean intensity was increased by 4.8 times by the CDDP-treatment and 6.1 times by the UV-irradiation, compared with that of untreated cells. The intensities among nuclei ranged widely in both treatments. In contrast, the mean intensity was not increased in XP-A cells by the same treatments. However, when XP-A cells were fused with normal cells with polyethylene glycol (PEG) treatment, the nuclei of the XP-A cells showed positive PCNA-staining following CDDP-treatment or UV-irradiation in almost all cases. These results suggest that the PCNA complex formation may play a role in the DNA repair process after the step where the factor deficient in XP-A cells is involved following CDDP-treatment as well as following UV-irradiation.

Cell Division↗
PubMed1992

Organ culture of psoriatic skin: effect of TGF-alpha and TGF-beta on epidermal structure in vitro.

Normal skin and uninvolved and involved psoriatic skin specimens were maintained in vitro in organ culture. The 3-4 mm punch-biopsied skin specimens were put freely into the culture medium with or without fetal calf serum, under an atmosphere of 95% O2 plus 5% CO2, and rotated at 60 rpm at 37 degrees C. In the serum-free culture medium (vitamin A-free) granular layers appeared in the involved psoriatic epidermis in culture. Addition of TGF-alpha caused normal skin and uninvolved and involved psoriatic skin specimens to become acanthotic and to degenerate easily almost to the full thickness of the epidermal layer in proportion to increasing concentrations of TGF-alpha as well as with the duration of the culture, but without disappearance of their granular layers. TGF-beta caused the normal skin and uninvolved psoriatic skin specimens to become thinned without disappearance of granular layers, but caused the involved psoriatic skin specimens to be thinned without appearance of granular layers in serum-containing medium or with their disappearance in the serum-free medium. TGF-beta also antagonized the acanthotic and degenerative effect of TGF-alpha. The results suggest that TGF-alpha and TGF-beta may partially be related to the induction of psoriatic epidermal lesions.

Humans↗
PubMed1992

Properties of isolated extrachromosomal nucleoli from Tetrahymena pyriformis.

Extrachromosomal nucleoli were isolated from log phase cells of Tetrahymena pyriformis (amicronucleate strain) in a highly purified state. Nucleoli located at the periphery of the macronucleus were detached from the nucleoplasmic mass of isolated macronuclei with agitation and separated from macronuclei by filtration through a Nuclepore membrane filter (pore size 5 microm). The filtrate constitutes the crude nucleolar preparation, as judged by electron microscopy and DNA analysis. Further purification of the nucleoli was performed by isopycnic centrifugation of the filtrate in a Metrizamide density gradient. After this step, the purity of the nucleoli, as defined by rDNA content and measured by analytical CsCl centrifugation, was almost 100%. Electron microscopy of the purified nucleoli revealed structures that resemble those of an in situ nucleoli. Undegraded 35S pre-rRNA, together with 26S and 17S rRNA, could be isolated from purified nucleoli. In vitro RNA synthetic activity was associated with isolated nucleoli. This activity is insensitive to low and high concentrations of alpha-amanitin, indicating that the form I RNA polymerase is functioning.

Animals↗
PubMed1992

CD7-positive acute myeloid leukemia: further evidence of cellular immaturity.

Among 63 cases of acute myeloid leukemia (AML), 14 were found to express the CD7 antigen, a cell surface marker usually found at an early stage during T lineage differentiation. The CD7-positive AML cases consisted of 5 cases of M1, 3 cases of M2, 3 cases of M4, 1 case of M5, 1 case of M6 and 1 case of M7. Among these 63 cases, the proportion of blast cells expressing the CD34 antigen was examined. The proportion of CD34-stained cells among the CD7-positive AML cases, although varying, was significantly larger than that among the CD7-negative AML cases (P less than 0.05). As the CD34 antigen was expressed on hematopoietic progenitor cells and was considered to reflect an early hematopoietic stage, the high proportion of cells expressing CD34 among the CD7-positive AML cases may support the notion that CD7-positive AML cells are immature.

Adolescent↗
PubMed1992

Circulating CD34+ hematopoietic progenitors in the harvesting peripheral blood stem cells; enhancement by recombinant human granulocyte colony-stimulating factor.

The number of circulating progenitor cells increases during the period of hematopoietic recovery following myeloablative therapy. These progenitor cells were used for autologous transplantation in order to reconstitute hematopoiesis. As an indicator of the circulating progenitor cells, the number of granulocyte-macrophage colony forming units (CFU-GM), which is measured by means of a long-term cell culture, has been widely used. Recently, a cell surface marker, CD34, which can easily be measured by means of flowcytometry, was found to represent immature hematopoietic progenitor cells, which are very close to stem cells. Therefore, the relationship between the number of CD34 positive cells (CD34+ cells) and the number of CFU-GM in the peripheral blood following chemotherapy was studied in 9 patients selected to undergo autotransplantation. The number of peripheral blood CD34+ cells was found to be significantly correlated with that of CFU-GM (r = 0.81). When four out of 9 patients received recombinant human granulocyte-colony stimulating factor (rG-CSF) administration, a significant increase in the release of peripheral blood CD34+ cells as well as peripheral blood CFU-GM was observed (P less than 0.01). Thus, the measurement of CD34+ cells is useful for predicting the number of circulating CFU-GM.

Adolescent↗
PubMed1992

Two types of proliferating cell nuclear antigen (PCNA) complex formation in quiescent normal and xeroderma pigmentosum group A fibroblasts following ultraviolet light (uv) irradiation.

We examined the relationship between the formation of proliferating cell nuclear antigen (PCNA) complex with DNA and nucleotide excision repair in human fibroblasts following ultraviolet light (uv) irradiation. PCNA complex formation was detected by the immunofluorescence method after methanol fixation and nucleotide excision repair activity was detected as the unscheduled DNA synthesis (UDS) by autoradiography labeled with [3H]thymidine. Quiescent normal cells showed a strong punctuated pattern of PCNA staining 5 min to 3 h and UDS 3 h after 10 J/m2 of uv irradiation, but they no longer showed PCNA staining and UDS 24 h after irradiation. In contrast, xeroderma pigmentosum group A (XP-A) cells, which lack UDS activity, did not show PCNA staining up to 30 min after irradiation; however, unexpectedly, they were stained 3 h and even 24 h after irradiation with their staining pattern being different from that in normal cells. Namely, the fluorescence spots in XP-A cells were larger in size and much smaller in number than those in normal cells. When XP-A cells were fused with normal cells with polyethylene glycol treatment, nuclei of XP-A cells showed a PCNA staining pattern similar to that of normal cells at 30 min, which was no longer detected 24 h after irradiation. These results suggest that there exist two types of PCNA complex formation, nucleotide excision repair-related and -unrelated, in human fibroblasts following uv irradiation.

Cell Fusion↗
PubMed1992

Developmental capacity of bovine oocytes cryopreserved after maturation in vitro and of frozen-thawed bovine embryos derived from frozen mature oocytes.

The present study was conducted 1) to investigate the post-thaw developmental capacity of in vitro mature bovine oocytes (Metaphase II) frozen by 1.6 M of 1,2-propanediol and 2) to confirm the viability of frozen bovine embryos derived from frozen mature oocytes. The cleavage and developmental rates to the blastocyst stage of frozen-thawed mature oocytes were significantly lower (P<0.01) than that of nonfrozen oocytes. When mature oocytes were treated with hyaluronidase, trypsin, or base solution (solution control) before processing to remove the cumulus cells, the developmental rates to the blastocyst stage of frozen-thawed oocytes were 2.8% (5/180), 3.1% (9/295) and 1.1% (1/89), respectively. The viability and developmental capacity of frozen-thawed bovine embryos derived from frozen mature oocytes were not different from those of frozen-thawed bovine embryos derived from nonfrozen mature oocytes (control). Furthermore, nonfrozen and frozen-thawed embryos derived from frozen-thawed mature oocytes were nonsurgically transferred to recipient cows. One of the four and one of the two recipient cows became pregnant, respectively. The results of this study demonstrated the viability of embryos obtained from frozen-thawed bovine oocytes at Metaphase II followed by in vitro fertilization and culture to the blastocyst stage in vitro.

Journal Article↗
PubMed1992

Imaging of subunit complexes of thermophilic bacterium H(+)-ATPase with scanning tunneling microscopy.

Using a scanning tunneling microscope (STM), we observed reconstructed subunit complexes of H(+)-ATPase of a thermophilic bacterium. The measurement was carried out in air without conductive coating on the samples deposited on a highly oriented pyrolytic graphite (HOPG). The F1 subunit complex of the H(+)-ATPase, and an H(+)-ATPase whose F0 portion was embedded into liposomes prepared from soybean lecithin were imaged. Overall structural images of the subunit complex F1 were obtained: the structural dimensions of the STM images are in agreement with those deduced from conventional methods such as an transmission electron microscopy (TEM) and small-angle X-ray scattering (SAX) experimentation. Regarding the STM imaging of these samples, we discuss the advantages and disadvantages of the STM over those of conventional methods such as a TEM and SAX.

Cloning, Molecular↗