Search PubMed⌕ Search

Biomedical subjects

Y Hashimoto

Publications and source records attributed to Y Hashimoto.

At least 1,549 records · Page 86Linked to original sources
PubMed1981

Inhibitory effect of 5-halogenated deoxyuridines on in vitro keratinization of a transformed rat urinary bladder epithelial cell line.

The effect of 5-halogenated deoxyuridines on the keratinization of an in vitro-transformed rat bladder epithelial cell line, BES20B, was studied by a cover slip culture method established previously. 5-Bromodeoxyuridine (BrdU) and 5-iododeoxyuridine (IdU) both showed dose-dependent inhibition of the keratinization. The complete inhibition of keratinization was achieved by BrdU at concentrations higher than 5 microgram/ml. At these concentrations, BrdU reduced the saturation density of the test cells on a cover slip. Removal of BrdU from the culture medium restored the cell growth as well as the keratinization of BrdU-treated cells, suggesting that the effect of BrdU is reversible. The effect of BrdU was abolished by the addition of excess thymidine. A possible mechanism of the anti-keratinization effect of BrdU is discussed in comparison with that of vitamin A.

Animals↗
PubMed1981

Factors influencing the autologous mixed lymphocyte reaction in rats: effect of xenogeneic serum protein.

Mixed culture of nylon non-adherent (T-enriched) spleen cells or lymph node cells of ACI/N or F344 rats with mitomycin C-treated autologous spleen cells resulted in the increased DNA synthesis of the responder T cells when they were cultured in medium containing foetal calf serum (FCS) or bovine serum albumin. This autologous mixed lymphocyte reaction (AMLR), however, proceeds little when the cells were cultured in medium containing autologous or allogeneic rat serum, irrespective of the responder:stimulator cell ratio and to the culture period. Furthermore, the AMLR response in FCS was greatly reduced if a relatively large number of macrophages were present in the responder cell population. These results suggest that the AMLR response is unlikely to occur in a physiological condition or in vivo.

Animals↗
PubMed1981

Alkylation of calf thymus DNA with reductively activated mitomycin C.

Mitomycin C (MMC) was catalytically reduced in the presence of a nucleotide or calf thymus DNA. Reaction with 5'-guanylic acid (5'-GMP) gave 1,2-cis-2, 7-diamino-1-(5'-guanylyl) mitosene. Reaction with calf thymus DNA gave modified DNA, which on enzymatic hydrolysis gave two alkylated 5'-deoxyguanylic acid (MG-1 and MG-2) and an alkylated 5'-deoxyadenylic acid (MA). This is the first example of isolation of nucleotides from DNA modified by MMC.

Alkylation↗
PubMed1981

Amino acid conjugation of N-hydroxy-4-aminoazobenzene dyes: a possible activation process of carcinogenic 4-aminoazobenzene dyes to the ultimate mutagenic or carcinogenic metabolites.

The activation process of N-hydroxy-4-aminoazobenzene (N-OH-AAB) dyes, proximate mutagenic or carcinogenic metabolites of AAB dyes, to the ultimate mutagenic or carcinogenic metabolites was studied by the use of an amino acid conjugation (aminoacylation) system catalyzed by yeast seryl-tRNA synthetase and [3H]ATP. A potent mutagen, N-hydroxy-3-methoxy-AAB (N-OH-3-MeO-AAB), as well as a non-mutagen, N-OH-2-MeO-AAB, were equally susceptible to N-O-serine conjugation. A weak mutagen, N-OH-AAB, and a moderate mutagen, N-OH-2,5-diMeO-AAB, were also susceptible to the aminoacylation, but to a lesser extent than the 2- or 3-methoxyl homologs. In contrast, N-hydroxy-N-methyl-4-aminoazobenzene and a moderate mutagen, N-OH-4'-MeO-AAB, were not susceptible to the aminoacylation. The ability of these N-OH-AAB dyes to bind with nucleic acid after serine conjugation was proportional to the susceptibility of the dyes to serine conjugation. Serine conjugates of N-OH-AAB dyes reacted with poly G, but not with poly A, poly C or poly U, suggesting that the azo dyes selectively bind with guanine base of nucleic acids. The susceptibility of N-OH-AAB dyes to aminoacylation was compared with the carcinogenic, mutagenic and unscheduled DNA synthesis-inducing activities of these and the mother AAB dyes.

Animals↗
PubMed1981

Cell surface antigens in normal and neoplastic urinary bladder epithelial cells of the rat.

Cell surface antigens of normal urinary bladder epithelium (NBE) and bladder cancers of inbred ACI/N rats were assayed by antisera raised in rabbits. Mixed hemadsorption test combined with absorption analysis defined three kinds of cell surface antigens in both NBE and bladder cancer cells; the first antigen was common to lymphoid cells, the second was present in most of the epithelia, and the third was unique to NBE and present to a lesser extent in bladder cancers. In addition, bladder cancers had a fourth antigen that was common only to epidermis. These findings were confirmed by the use of typing sera for the third and the fourth antigens, which were prepared by absorptions of each antiserum with lymphoid cells and the lung. Direct titration of the typing sera against various cells revealed that the third antigen (NBE antigen) was species-specific and the fourth antigen (BC-SK antigen) was not common to human bladder cancers but common in part to mouse epidermal cells and bladder cancers.

Animals↗
PubMed1981

Emergence of an epidermis-associated cell surface antigen in epithelial cells of the rat urinary bladder in carcinogenesis.

Inbred ACI/rats were treated with a selective urinary bladder carcinogen N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN). Two cell surface antigens on the epithelial cells of the bladder, normal bladder epithelium (NBE) antigen unique to normal epithelial cells of the bladder and BC-SK antigen specific for bladder cancer and epidermis, were periodically assayed by mixed hemadsorption test with the typing sera against each antigen. Treatment with BBN for 8 or more weeks induced papillomas or cancers that expressed a definite level of BC-SK antigen, whereas a 4-week treatment did not render the bladder cells with a significant level of this antigen. In general, the level of NBE antigen in bladder cells was not altered by the BBN treatment. In vitro culture of bladder cells of BBN-treated rats resulted in an increase in the level of BC-SK antigen as opposed to a decrease in the NBE antigen level. BC-SK antigen was not detected in epidermal cells of rats younger than 3 days, but it emerged in these cells by in vitro culture for longer than 4 days.

Animals↗
PubMed1981

Improvement of the preparation method for vaginal smears for the auto-cyto-screener.

An improved method of preparing vaginal smears for use in the Auto-Cyto-Screener is reported. The main alterations from the previous technique were the substitution of 2% formaldehyde phosphate buffer (pH 7.4) for 50% ethanol as the preservative fluid, the use of homogenization in place of sonication for cell aggregate dispersion and the introduction of Ficoll-gradient sedimentation, which not only removes leukocytes and other elements from the suspensions but also concentrates the cancer cells to some extent. An examination of cell deposition techniques showed that optimal results were achieved with the use of filter paper, not rubber, and with centrifugation performed immediately after loading the suspension into the chambers.

Autoanalysis↗
PubMed1981

Mutagenicity of 4-aminoazobenzene, N-hydroxy-4-aminoazobenzene, 4-nitrosoazobenzene, 4-nitroazobenzene, and their ring methoxylated derivatives on Salmonella.

The mutagenicities of 4-aminoazobenzene (AAB), N-hydroxy-4-aminoazobenzene, 4-nitroazobenzene, and their 2-, 3-, 4'-methoxyl and 2,5-dimethoxyl derivatives, and 2- and 3-methoxy-4-nitrosoazobenzene were examined on Salmonella typhimurium TA98 and TA100. The activities of AAB dyes upon S-9 metabolic activation were related to their carcinogenic activities in the rat. The potent carcinogen 3-methoxy-AAB was a potent mutagen for both tester strains. The moderate or weak carcinogens 4'-methoxy-AAB and AAb were moderate or weak mutagens for one or both of the tester strains. The non-carcinogens 2-methoxy-AAB and 2,5-dimethoxy-AAB were non-mutagenic. In contrast to AAB dyes, N-hydroxy-AAB dyes showed greater mutagenicity than the mother AAB dyes, without S-9 treatment. 4-Nitroazobenzene dyes and 4-nitrosoazobenzene dyes showed mutagenicity without S-9 treatment, and the activities were related to those of the corresponding N-hydroxy-AAB dyes. All 4-nitroazobenzene dyes were mutagenic in the presence of S-9, suggesting the production of mutagens other than N-hydroxy-AAB dyes by the S-9 treatment. The cytotoxicity of azo dyes to bacteria had no apparent relation to the mutagenic activity of the azo dyes. Incubation of 4-nitroazobenzene dyes with TA100 bacteria yielded N-hydroxy-AAB dyes. The synthesis and properties of new N-hydroxy-AAB dyes, 4-nitroazobenzene dyes and 4-nitrosoazobenzene dyes are described.

Azo Compounds↗
PubMed1981

Metabolic fate and carcinogenicity of N-(omega-hydroxyalkyl) N-(4-hydroxybutyl) nitrosamines analogs of N-butyl-N-(4-hydroxy-butyl) nitrosamine, in the rat.

The metabolic fate and carcinogenicity fo three omega-hydroxy derivatives of N-alkyl-N-(4-hydroxybutyl) nitrosamines, potent bladder carcinogens, were investigated in the rat. They were N-(2-hydroxyethyl)-N-(4-hydroxybutyl)-nitrosamine (HEHBN), N-(3-hydroxypropyl)-N-(4-hydroxybutyl) nitrosamine (HPHBN), and N-N-bis(4-hydroxybutyl) nitrosamine (BHBN). The principal urinary metabolite of HEHBN as well as HPHBN was identified as the corresponding 3-carboxypropyl compound, while the main metabolite of BHBN was N,N-bis (3-carboxypropyl) nitrosamine, indicating the preferential metabolic oxidation of the 4-hydroxybutyl chain to the 3-carboxypropyl group in the N-(omega-hydroxyalkyl)-N-(4-hydroxybutyl) nitrosamines. All three N-nitrosamines having the 4-hydroxybutyl chain induced neither bladder tumor nor any tumor in other organs under conditions similar to those used for N-alkyl-N-(4-hydroxy-butyl) nitrosamines. The essential structural and metabolic requirements in N-nitrosamines for the induction of bladder cancer in the rat are discussed.

Animals↗
PubMed1981

Human neutrophil aggregation and increased adherence to human endothelial cells induced by heat-aggregated IgG and immune complexes.

Several types of IgG-dependent phagocytic stimuli independent of complement were investigated for their property to induce human polymorphonuclear neutrophil leucocyte (PMN) aggregation and adherence to human endothelial cells (EC) in culture. A Coulter counter method was employed for the detection of cell aggregation. Aggregated IgG, ovalbumin-anti-ovalbumin (OV anti-OV) immune complexes (both insoluble and soluble) and opsonized latex particles induced a significant degree of PMN aggregation which was detectable as early as 2 min after exposure of PMN to these stimuli. This aggregation was dependent on divalent cations (Ca++, Mg++). The same phagocytic stimuli furthermore significantly increased adherence of PMN to cultured human EC and serum-coated plastic. Controls consisting of native IgG, and OV anti-OV complexes prepared from Fab')2 antibody failed to induce either aggregation or increased adherence of PMN. These data suggest that exposure of PMN to IgG-dependent phagocytic stimuli induces increased adhesiveness of PMN and that interaction between the Fc-receptor of PMN and the Fc-portion of phagocytic stimuli is essential for this effect.

Antigen-Antibody Complex↗
PubMed1981

Cytotoxic cells induced in tumor-bearing rats by a streptococcus preparation (OK-432).

The characteristics of the cytotoxic cells induced by ip injections of an immunoadjuvant, OK-432 (Picibanil), into ACI/N rats bearing syngeneic bladder cancer, BC47, were examined. The cytostatic activity, but not the cytolytic activity, of peritoneal macrophages was augmented when either normal or cancer-bearing rats were treated with OK-432. In contrast, the plastic nonadherent cells of the peritoneal exudate cells from OK-432-treated cancer bearing rats, but not lymph node cells or spleen cells, killed all ACI/N rat bladder cancers tested as well as ACI/N rat hepatoma cells and Meth-A mouse sarcoma cells. The plastic nonadherent cells from OK-432-treated normal rats also killed hepatoma cells and Meth-A cells, but not bladder cancer cells. The cytolytic cells that were induced in cancer-bearing rats by OK-432 treatment and showed cytolytic activity specific for bladder cancer were found to be sensitive to anti-rat thymocyte serum and complement, nylon-adherent, and Fc receptor-negative. The cells that showed nonselective cytolytic activity were nylon-adherent and insensitive to anti-rat thymocyte serum and complement.

Animals↗