Biomedical subjects

G Fujii

Publications and source records attributed to G Fujii.

At least 19 recordsLinked to original sources

PubMed1992

The crystal structure of diphtheria toxin.

The crystal structure of the diphtheria toxin dimer at 2.5 A resolution reveals a Y-shaped molecule of three domains. The catalytic domain, called fragment A, is of the alpha + beta type. Fragment B actually consists of two domains. The transmembrane domain consists of nine alpha-helices, two pairs of which are unusually apolar and may participate in pH-triggered membrane insertion and translocation. The receptor-binding domain is a flattened beta-barrel with a jelly-roll-like topology. Three distinct functions of the toxin, each carried out by a separate structural domain, can be useful in designing chimaeric proteins, such as immunotoxins, in which the receptor-binding domain is substituted with antibodies to target other cell types.

Bacterial Toxins↗

PubMed1992

A molecular model for membrane fusion based on solution studies of an amphiphilic peptide from HIV gp41.

The mechanism of protein-mediated membrane fusion and lysis has been investigated by solution-state studies of the effects of peptides on liposomes. A peptide (SI) corresponding to a highly amphiphilic C-terminal segment from the envelope protein (gp41) of the human immunodeficiency virus (HIV) was synthesized and tested for its ability to cause lipid membranes to fuse together (fusion) or to break open (lysis). These effects were compared to those produced by the lytic and fusogenic peptide from bee venom, melittin. Other properties studied included the changes in visible absorbance and mean particle size, and the secondary structure of peptides as judged by CD spectroscopy. Taken together, the observations suggest that protein-mediated membrane fusion is dependent not only on hydrophobic and electrostatic forces but also on the spatial arrangement of the amino acid residues to form an amphiphilic structure that promotes the mixing of the lipids between membranes. A speculative molecular model is proposed for membrane fusion by alpha-helical peptides, and its relationship to the forces involved in protein-membrane interactions is discussed.

Amino Acid Sequence↗

PubMed1992

[A case of malignant localized visceral pleural mesothelioma].

We experienced malignant localized mesothelioma of which origin was visceral pleura. According to, 1) the preoperative chest X-ray and chest CT which showed extra-pleural sign, 2) the rapid tumor growth, and 3) the result from needle biopsy, we diagnosed malignant localized mesothelioma of which origin was parietal pleura. Surgical treatment was performed, and diagnosed that its origin was visceral pleura. The tumor invaded the lung. It is dangerous to diagnose by means of needle biopsy because of malignant cell implantation. We recommend that firstly the surgical treatment should be carried out for malignant mesothelioma, which needs extended resection for preventing its recurrence.

Humans↗

PubMed1991

Crystallization of diphtheria toxin.

Two new crystal forms (forms III and IV) have been grown of diphtheria toxin (DT), which kills susceptible cells by catalyzing the ADP-ribosylation of elongation factor 2, thereby stopping protein synthesis. Forms III and IV diffract to 2.3 A and 2.7 A resolution, respectively. Both forms belong to space group C2; the unit cell parameters for form III are a = 107.3 A, b = 91.7 A, c = 66.3 A and beta = 94.7 degrees and those for form IV are a = 108.3 A, b = 92.3 A, c = 66.1 A and beta = 90.4 degrees. Both forms have one protein chain per asymmetric unit with the dimeric molecule on a twofold axis of symmetry. Form IV is exceptional among all crystal forms of DT in that it can be grown reproducibly. Thus the form IV crystals should yield a crystallographic structure giving insight into the catalytic, receptor-binding and membrane-insertion properties of DT.

Crystallization↗

PubMed1991

Activin receptor mRNA is expressed early in Xenopus embryogenesis and the level of the expression affects the body axis formation.

Activin is a member of the transforming growth factor beta (TGF-beta) and possesses various activities in cellular control phenomena. During Xenopus embryonic development, activin is thought to act as a natural mesoderm-inducing factor. We isolated here the Xenopus activin receptor cDNA from Xenopus tadpole cDNA library and examined the expression of the Xenopus activin receptor gene during the course of early embryonic development. The Xenopus activin receptor has an 87% homology at the level of deduced amino acid sequence with the mouse activin receptor, and using the cDNA obtained, three bands of mRNA with different lengths were detected in Xenopus embryos throughout early embryogenesis. We synthesized activin receptor mRNA in vitro and tested the effect of the injection of the mRNA into Xenopus fertilized eggs on subsequent development. When the synthetic mRNA was injected into uncleaved fertilized eggs, embryos with reduced trunk structure were formed. However, when the mRNA was injected into the ventral blastomeres at the 16-cell stage, embryos with a secondary body axis were formed. These results indicate the importance of the function of activin receptor in the regulatory mechanism for body axis formation.

Activin Receptors↗

PubMed1991

Deduced primary structure of a Xenopus proteasome subunit XC3 and expression of its mRNA during early development.

Proteasome is a non-lysosomal proteinase complex ubiquitously distributed in eukaryotic cells. We isolated here the cDNA clone for one of the proteasome subunits (XC3) from Xenopus ovary cDNA libraries using rat RC3 cDNA as a prove. The cDNA is 885 bp long and encodes 234 amino acids. The deduced amino acid sequence is highly homologous (95.3%) to those of rat RC3 and human HC3 subunits. The mRNA for XC3 is one of the maternal mRNAs and detected at all the embryonic stages investigated, but its level changes in a characteristic way especially at the gastrula stage. We suggest that the highly conserved XC3 subunit plays an essential role in proteasome function and also that during Xenopus embryogenesis mRNA for XC3 subunit is replaced from maternal to newly-synthesized one probably around the gastrula stage.

Amino Acid Sequence↗

PubMed1988

Effects of repeated exposure to cyclophosphamide on drug resistance and biological properties of a newly autonomy-acquired mouse mammary tumor (T4-OI320).

T4-OI320 tumors, the autonomous but estrogen receptor (ER-)-positive subline recently established from the pregnancy-dependent TPDMT-4 mouse mammary tumor, were characterized by moderate sensitivity to 1 mg cyclophosphamide (CY) and high sensitivity to 20 micrograms mitomycin C (MMC) and 1.5 mg 5-fluorouracil (5FU) twice weekly, the modal chromosome number of 40, the mean ER level of 20.8 fmol/mg protein, and a population of cells with one exogenous mouse mammary tumor virus (MMTV) genome. Serial tumor passages under CY treatment were conducted to investigate the effects of continued chemotherapy on growth habit, drug resistance, ER, karyotype, proviral MMTV genome and 22 oncogenes including int-1 and int-2. The growth rate was 2.9- and 4.5-fold increased after 10 and 20 passages, respectively. Along with this, the tumors acquired greater or complete resistance to CY and MMC similar to each other in antitumor mechanism, but maintained similarly high sensitivity to 5FU different from CY in antitumor mechanism. The ER level remained the same as but declined to half of the initial level after 10 and 20 passages, respectively. Tumor cells became more heterogenous in karyotype and the proportion of hyperdiploid cells with 41 to 47 chromosomes increased, resulting in shift of the modal number to 42 after 20 passages: Cells with 42 chromosomes accounted for 41% of the population. The exogenous MMTV bands in the Southern blotting became more intense after CY treatment accompanying neither amplification nor rearrangement of any cellular oncogenes. The tumors transplanted under no treatment for 20 generations had 1.5-fold higher growth rate, slightly stronger resistance to CY and MMC, similarly high sensitivity to 5FU, 4-fold lower ER level, the same distribution of chromosome numbers compared to the original tumors and similar intensity of the exogenous MMTV bands. Thus, acquisition of higher growth potential and greater drug resistance in the course of CY treatment appeared to be associated with chromosomal changes and selective overgrowth of the particular cell population with exogenous MMTV information in this model.

Animals↗

PubMed1987

Preliminary study for application of anti-alpha-fetoprotein monoclonal antibody to boron-neutron capture therapy.

Boron-neutron capture therapy (BNCT) has been applied clinically, especially in brain-neuro surgery. We intended to expand the application of BNCT for the treatment of abdominal cancers and tried to determine whether MoAb (monoclonal antibody) against AFP (alpha-fetoprotein) could be useful tool to deliver boron-10 (10B) to AH-66 hepatoma cells for BNCT. Firstly, MoAb was boronated by mixing with 10B-compound (Cs2 10B12H11SH) by using N-succinimidyl 3(2-pyridyldithio)propionate (SPDP). Numbers of 10B atoms bound to an antibody molecule were in proportion to the dose of 10B-compound added, and maximum number of 10B atoms conjugated to an antibody molecule was approximately 1240. Secondly, using this boronated MoAb, 10B was delivered to AH-66 cells, and 11 X 10(9) 10B atoms were estimated to be on and/or in an AH-66 cell. After the irradiation with thermal neutron, boronated AH-66 cells showed decreasing uptake of [3H]TdR in proportion to the number of 10B atoms bound to and/or incorporated into the tumor cells. These results indicate that 10B atoms delivered by MoAb exert cytotoxic effect on AH-66 cells in a dose dependent manner by thermal neutron irradiation.

Animals↗

PubMed1987

[A case of metastasis of renal cell carcinoma to the abdominal wall 13 years after nephrectomy].

A 68-year-old man was admitted to our hospital complaining of a tumor of the left abdominal wall. Thirteen years previously, had undergone a nephrectomy of a right renal cell carcinoma with T2, N0, M0, manifestations stage I. Prior to his second operation, a parenchymal tumor was strongly suspected. The tumor, however, was finally diagnosed pathologically as being a metastatic renal cell carcinoma. Postoperatively, the patient has been well for 21 months without any evidence of recurrence at the time of this report. Long-term follow-up is thought to be essential for cases of renal cell carcinoma with a slow-growing type of metastasis.

Abdominal Muscles↗

PubMed1986

Expression of transferrin receptor on human carcinomas--an immunohistological study.

Thirty specimens taken from 25 adenocarcinomas, 1 squamous cell carcinoma, 2 anaplastic carcinomas and 2 malignant lymphomas were studied for the presence of transferrin receptor (TR). Immunoperoxidase technique was used and OKT9, an anti-transferrin receptor monoclonal antibody, was introduced. The tissue localization of carcino-embryonic antigen (CEA) and epithelial membrane antigen (EMA) were also studied. Of these, 5 cases were strongly stained for TR, 17 moderately and 6 weakly stained. TR was demonstrated on the basal site while luminal preference was evident with CEA and EMA. This polarity was observed in the well- to moderately-differentiated adenocarcinomas and in the well-differentiated squamous cell carcinoma but not in the poorly-differentiated and anaplastic variants. Putatively normal epithelium registered very weak positivity though the polarity was still maintained.

Adenocarcinoma↗

PubMed1986

Effect of cerulenin, an inhibitor of fatty acid synthesis, on the immune cytolysis of tumor cells.

Effect of cerulenin, an inhibitor of biosynthesis of fatty acids and sterols on the immune cytolysis of tumor cells was investigated. In cytotoxicity experiment, MH134 cells pretreated with cerulenin in a range of concentrations causing minor cellular injuries were lysed by xenogeneic antiserum and complement in a significantly higher degree than non-treated MH134 cells. C3H/He mice inoculated ip with 1 X 10(5) syngeneic MH134 cells, received cerulenin on days 3 and 6, and then the antiserum against MH134 cells on days 4 and 7. Such mice survived markedly longer than 3 control groups of mice carrying MH134 tumor cells; one without treatments, one treated only with cerulenin and the other only with the antiserum. Inhibition of biosynthesis of cell membrane fatty acid and sterols, that was indicated by inhibition of 14C-acetate incorporation, is thought to enhance the susceptibility of the tumor cells to killing by antibodies and complement. Such an inhibitor of fatty acids and sterols might be a beneficial adjuvant to the adoptive cancer immunotherapy.

Acetates↗

PubMed1985

Characterization of a human rhabdomyosarcoma cell strain in tissue culture.

A new human rhabdomyosarcoma cell strain, designated KYM-1, has been established from a neck tumor found in a 9-month-old infant. The cultured cells were round and mainly free-floating or in a moniliform pattern with a population doubling time of 75 hours. In stained preparations, the cells were pleomorphic and had a single round or oval nucleus in non-striated cytoplasm. However, the intracellular presence of myogenic markers was clearly shown by enzyme-immunochemical stains. An ultrastructural feature of the KYM-1 cells was the presence of numerous intermediate filaments in the perinuclear area and around the Golgi complexes which were associated with abundant cell organelles and aggregates of glycogen granules. High viscosity of the spent culture medium was attributed to hyaluronic acid, identified by electrophoresis and hyaluronidase digestion, and immunological and biochemical analyses revealed that the increased concentration of plasminogen activator activity found in the culture medium was almost wholly of the tissue plasminogen activator type. The KYM-1 cells also contained high concentrations of alkaline phosphatase activity. Tumorigenicity of the cells was confirmed by heterotransplantation into hamsters treated with anti-thymocyte serum.

Animals↗

PubMed1985

Amplification of c-yes-1 proto-oncogene in a primary human gastric cancer.

Abnormalities of cellular oncogenes in 22 cases of human primary gastric cancer were screened by Southern blot analysis using 16 onc probes. Human cellular sequences related to the v-yes oncogene of Y73 avian sarcoma virus (human c-yes-1 gene) were found to be amplified in a primary gastric cancer. The degree of amplification was about 4- to 5-fold. Another v-yes-related cellular gene (human c-yes-2, a pseudogene) was not amplified in this tumor. The normal stomach tissue adjacent to the tumor tissue in the same patient showed no amplification of c-yes-1 gene, suggesting that the amplified c-yes-1 is involved in the onset or the progress of this carcinoma.

Electrophoresis, Agar Gel↗

PubMed1984

Krestin (PSK).

A polysaccharide preparation isolated from Coriolus versicolor (Fr.) Quél. of Basidiomycetes (PSK) predominantly consists of glucan and approximately 25% tightly bound protein. PSK was effective against various allogeneic and syngeneic animal tumors and has been given orally to cancer patients. Various suppressed or enhanced immune responses of tumor-bearing animals were restored to normal levels by the administration of PSK in the tumor models tested. The killer T cell activity was augmented in tumor-bearing mice by intraperitoneal or oral administration of PSK, and there was correlation between the PSK associated antitumor effect and the killer T cell activity. It was found that PSK competed with immunosuppressive substances isolated from tumor-bearing mice and that the intestinal immune system appeared to be modulated by oral administration of PSK. After oral administration of 14C- or 35S-labeled PSK to normal rats, it was found that small or large molecular substances appeared in the serum depending on the time elapsed after administration, an indication that large molecular size products were from the digestive tract.

Amino Acids↗

PubMed1984

[Combined therapy with microwave hyperthermia and adriamycin in MM2-bearing mice].

C3H/He mice were inoculated i.p. with synergic MM2 tumor cells(2 X 10(6) cells/mouse), and subsequently treated either by systemic hyperthermia induced by microwave irradiation (2450 MHz)alone, administration of ADM alone, or a combination of both. The mice were exposed to hyperthermia for 5 minutes everyday at an output of 10, 20 or 30 watts. ADM was administered i.p. for 3 days at dose levels of 0.025 mg/kg, 0.05 mg/kg or 0.075 mg/kg body weight. The mean survival time and the mean relative body weight were recorded. From these data, tumor-suppressing effects of the treatments were analysed by one-way or two-way variance analysis. Mice treated with 30-watt microwave irradiation survived significantly longer than control mice without treatment (P less than 0.05), as did mice treated with ADM alone (P less than 0.01). The mean relative body weight was similar among the microwave, ADM and control groups. When the mice were given microwave treatment combined with ADM, significant difference was observed in the mean survival time by one-way variance analysis (P less than 0.01), but no significant difference was observed by two-way variance analysis. The best condition of mice and the optimal dose of ADM still remain to be determined to facilitate more efficient tumor-suppression using this combination therapy.

Animals↗

PubMed1983

[Tumor suppressing effect of systemic hyperthermia with 2350 MHz microwaves combined with 5-fluorouracil in mice].

C3H/He mice were inoculated i.p. with syngeneic MM2 tumor cells (2 X 10(6) cells/mouse), and they were subsequently treated by systemic hyperthermia with microwave irradiation (2450 MHz) alone, administration of 5-FU alone, or a combination of the both. The mice were exposed to hyperthermia for 5 minutes everyday with an output of 10, 20 or 30 watts. 5-FU was administered i.p. for 3 days at dose levels of 2.5 mg/kg, 5 mg/kg or 10 mg/kg body weight. The mean survival time and the mean relative body weight were recorded. From these data, tumor-suppressing effects of the treatments were analyzed by one-way variance analysis or two-way variance analysis. The mice treated with microwave irradiation alone or 5-FU alone survived significantly longer than the control mice receiving no treatment (P less than 0.01). However, no significant difference in mean survival time was observed between the microwave group and the 5-FU group. The mean relative body weight was similar among the microwave, the 5-FU and the control group. When the mice were treated with microwave irradiation and 5-FU, significant difference was observed in the mean survival time (P less than 0.01), and the combination of microwave irradiation with an output of 20 W and 10 mg/kg of 5-FU seemed to be optimal. Determination of an optimal combination was difficult with the mean relative body weight, because body weight decreased due to side effect of the combination therapy.

Animals↗

PubMed1982

Immune response to alien histocompatibility antigens on Epstein-Barr virus transformed cells.

Expression of alien histocompatibility antigens on Epstein-Barr virus transformed, cultured lymphoblastoid cell lines (LCL), which were established from normal peripheral blood lymphocytes (PBL), was studied by means of mixed lymphocyte reaction (MLR), cell mediated lysis (CML) and primed lymphocyte typing (PLT). Stimulation of PBL by autologous LCL resulted in some MLR responses and generation of cytotoxic effector cells against autologous LCL. Restimulation of PBL by 16 individual allogeneic PBL failed to prime an individual lymphocytes against autologous LCL in PLT tests. However, stimulation of PBL by a pooled normal PBL resulted in generation of cytotoxic cells against autologous LCL. Culturing of stimulated PBL in the presence of T cell growth factor (TCGF) for 30 days was shown to maintain cytotoxic effector cells in the cell population.

Cell Line↗

PubMed1979

Cross-reactive antibodies against human cultured B cells and bovine erythrocytes in human renal transplantation sera.

Sera of 58 recipients of renal allografts were studied for the presence of antibodies against cell cultures of human B lymphoid cell lines (B-LCL) and bovine erythrocytes (BRBC). Cytotoxic anti-B-LCL antibodies were found in 13% of the sera from recipients with the grafts and in 67% of the sera obtained after removal of the rejected grafts. Most of these sera also contained BRBC lysins of high titers. Absorption studies showed that the anti-B-LCL antibodies are directed against antigens shared by BRBC and that they can be absorbed with corresponding graft tissues. The specificity of BRBC lysins found in some of the transplantation sera was shown to be similar to that of Hanutziu-Deicher antibodies.

Absorption↗