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Biomedical subjects

T Takeuchi

Publications and source records attributed to T Takeuchi.

At least 1,243 records · Page 69Linked to original sources
PubMed1990

Improved antitumor effects of 3'-deamino-3'-morpholino derivatives of pirarubicin.

The preparation and antitumor effects of 3'-deamino-3'-morpholino derivatives of pirarubicin are described. Di-N-alkylation of pirarubicin with bis(2-iodoethyl)ether gave 3'-morpholino-pirarubicin, which was converted into its 13-tosylhydrazone, 13-deoxy derivative and 13-(S)- and 13-(R)-dihydro derivatives. Intraperitoneal administration to murine tumors indicated that the effective dose ranges of the compounds having sp3 carbon at C-13 position were broader than those of the compounds having sp2 carbon. By oral administration, 13-(S)-dihydro isomer was more effective than 13-(R)-dihydro isomer.

Administration, Oral↗
PubMed1990

Probestin, a new inhibitor of aminopeptidase M, produced by Streptomyces azureus MH663-2F6. II. Structure determination of probestin.

Probestin, a new inhibitor of aminopeptidase M, has been isolated from the culture broth of Streptomyces azureus MH663-2F6. The 1H and 13C NMR studies and amino acid analysis confirmed the presence of one 3-amino-2-hydroxy-phenylbutanoic acid, leucine and two proline residues in the molecule. Stereochemistries of these amino acids were determined by HPLC analysis. The fragmentation pattern shown in the mass spectrum and the chemical analysis on probestin clarified the amino acid sequence. Thus the structure of probestin was defined as (2S,3R)-3-amino-2-hydroxy-4-phenylbutanoyl-L-leucyl-L-prolyl-L-pro line.

Amino Acid Sequence↗
PubMed1990

Deoxyspergualin therapy in autoimmune MRL/1pr mice suffering advanced lupus-like disease.

The present study was designed to evaluate the therapeutic activity of a novel immunosuppressive agent, deoxyspergualin (DSG, NKT-01) in male MRL/MpJ-lpr/lpr (MRL/lpr) mice suffering advanced systemic lupus erythematosus (SLE)-like lesions. Treatment with DSG in the early phase of the disease at doses of 1.5 and 3 mg/kg strongly suppressed the development of SLE-like lesions. When DSG was administered from week 21 through 29 to MRL/lpr mice in advanced phases of the disease, a daily iv dose of 3 mg/kg (5 days/week) markedly reduced the symptoms, whereas a dose of 1.5 mg/kg did not. Moreover, DSG treatment at a dose of 3mg/kg, started at the time when the blood urea nitrogen levels were over 50 mg/deciliter, significantly prevented deterioration of the hyperuremia. Taking these findings into consideration, DSG was found to be a promising agent for curing such established autoimmune disease.

Animals↗
PubMed1990

Deoxyspergualin directly suppresses antibody formation in vivo and in vitro.

The effect of deoxyspergualin (DSG, NKT-01) on humoral immunity was investigated both in vitro and in vivo. DSG inhibited the primary and secondary responses to T cell-dependent antigens and the response to T cell-independent antigens in thymic and athymic mice. However, natural antibodies in non-sensitized mice were affected less by the administration of DSG. The agent produced a dose-dependent inhibition of B cell proliferation and antibody production to lipopolysaccharide in vitro. Suppression of secondary antibody response was also shown, whenever antigen stimulation was not given, antibody production was not affected. These results suggest that DSG affects the proliferative stage of B lymphocytes in such a way as to inhibit their growth and antibody production.

Animals↗
PubMed1990

Production, isolation and structure determination of a novel beta-glucosidase inhibitor, cyclophellitol, from Phellinus sp.

In the course of our screening of beta-glucosidase inhibitor, a culture filtrate of a mushroom, Phellinus sp. strongly inhibited the enzyme activity. The active substance was isolated through charcoal separation, column chromatography and crystallization. Spectroscopic and crystallographic analysis revealed that it had a novel cyclitol structure, (1S,2R,3S,4R,5R,6R)-5-hydroxymethyl-7-oxabicyclo[4,1,0]heptane-2,3,4-tri ol, and we named it cyclophellitol. It inhibited almond-derived beta-glucosidase with an IC50 of 0.8 micrograms/ml.

Basidiomycota↗
PubMed1990

Biological activities of new anthracyclines containing fluorine, FAD104 and its metabolites.

From various new anthracyclines containing fluorine in their sugar moieties, 7-O-(2,6-dideoxy-2-fluoro-alpha-L-talopyranosyl)adriamycinone-14-hemi pimerate (FAD104) has been selected for clinical investigation, because of its excellent antitumor activity and solubility. In this paper, the mechanism whereby FAD104 exhibits good antitumor activity in vivo was studied through experiments in vitro in comparison with doxorubicin (DOX). FAD104 had weaker activity than DOX in DNA single and double strand scission in P388 cells and in binding to calf thymus DNA. FAD104 was taken up by P388 cells faster than DOX. The ester linkage in FAD104 was gradually hydrolyzed at neutral pH. FAD104 was metabolized to 7-O-(2,6-dideoxy-2-fluoro-alpha-L-talopyranosyl)adriamycinone (FT-ADM) when incubated with mouse or human serum. In mouse serum the esterase activity was about 100 times higher than in human serum. The product of nonenzymatic and enzymatic esterolysis, FT-ADM, was rapidly taken up by P388 cells and accumulated, reaching at a 9.7-fold higher level than DOX. Thus FAD104 was less active than DOX in itself, but it showed much higher activity through conversion into FT-ADM, due to the action of esterase or to spontaneous and gradual hydrolysis at physiological pH. 7-O-(2,6-Dideoxy-2-fluoro-alpha-L-talopyranosyl)adriamycinol (FT-ADM-OH), another metabolite found in mouse serum had the least biological activity among the fluorine-containing anthracycline glycosides, but its activity was still higher than DOX.

Animals↗
PubMed1990

Amebiasis in institutions for the mentally retarded in Kanagawa Prefecture, Japan.

A parasitologic survey of 620 mentally retarded patients, institutionalized in five different facilities in Kanagawa Prefecture, revealed a high incidence (12.6%) of infection with Entamoeba histolytica. A concomitant serologic survey, by the indirect fluorescent antibody test, gave a much higher incidence (26.5%). Moreover, most zymodeme patterns of the amebae isolated from infected individuals were of a pathogenic type (Zymodeme II). Our findings demonstrate that the mentally retarded in Japan, as in the United States, still are plagued by a high rate of amebic infection.

Adult↗
PubMed1990

Expression of virally-transduced mouse tyrosinase in cultured chick embryo cells.

A cDNA encoding mouse tyrosinase was inserted into a plasmid containing the provirus of a replication competent Avian Leukosis Virus (ALV). A viral stock produced from the plasmid was used to infect cultured tyrosinase-negative (ca/ca) unpigmented chick embryo pigment cells. Five days after infection many cells were producing very dark discrete pigment granules. Cultures of tyrosinase positive, sex linked albino (sal) pigment cells produced no additional pigmentation. White Leghorn pigment cells responded to viral infection like the sal pigment cells.

Animals↗
PubMed1990

[O-serotypes, biochemical properties and antimicrobial susceptibilities of Serratia marcescens isolated from clinical specimens (2nd report)].

O-serotypes, biochemical properties and drug resistances of Serratia marcescens (129 strains) isolated from clinical specimens in Showa University Fujigaoka Hospital from April 1985 to March 1987, were compared with those of the previous results (Jpn J Clin Pathol 35:555-560, 1987). The isolation frequencies of serotype O 3 and O 23 strains were 35.7% and 8.5%, respectively. These strains with serotype O 3 or O 23 were wide-spread in the hospital. The urea-positive strains which occupied 61.2% of all isolates tended to increase more than those of the previous report. The isolation frequency of gelatin-positive and melibiose-negative strains was 85.5%. The resistance rate of all isolates to latamoxef and aminoglycosides significantly increased, comparing with the previous report (p less than 0.01, chi 2-test). The susceptibility of serotype O 3 strains to gentamicin and minocycline significantly increased (p less than 0.005). All of serotype O 23 strains were urea-negative. The resistance rate to kanamycin, tobramycin, gentamicin and nalidixic acid was higher than that of the other serotype strains. Furthermore, the resistance rate to ofloxacin showed the lowest (8.6%) among pyridonecarboxylic acids.

Aminoglycosides↗
PubMed1990

[The expression of ras p21 product in hepatocellular carcinoma].

To elucidate the cell biological significance of ras oncogene, the expression of ras-p21 was analyzed in 53 cases of liver tissues including 34 cases of hepatocellular carcinoma (HCC), by using immunohistochemical method. In result, 22 (65%) cases of 34 HCC and 34 (79%) cases of 43 liver cirrhosis were positive for p21, whereas all of chronic hepatitis and normal livers were negative. Especially, comparative study between the expression of p21 and clinicopathological background of HCC revealed that p21 was prominently expressed in well differentiated form, nodular type, small liver cancer, and the cases showing AFP levels below 400 ng/ml. From these results, it was indicated that ras oncogene might play an important role in malignant transformation of hepatocytes or differentiation of HCC.

Carcinoma, Hepatocellular↗
PubMed1990

[Influence of gastric juice on human amylase activity].

Although it is well established that amylase activity is inactivated by acid, little is known about the influence of native gastric juice on amylase activity. We investigated the effect of gastric juice, acid, and pepsin on both pancreatic (P-) and salivary (S-) isoamylase activities in vitro. S- and P-isoamylase activities were completely inactivated by HCl (10 mEq/l), but 20% of each isoamylase activity remained when bovine serum albumin (BSA) (3%) was added. However pepsin (0.2 tyrosine mg/ml/min) inactivated both isoamylase activities even though BSA was added. When saliva or pancreatic juice was mixed with gastric juice, both isoamylase activities were detected until the mixing ratio was 3:7 (gastric juice:saliva or pancreatic juice, v/v). It is suggested that some of both isoamylase activities could survive after exposure to gastric juice in the stomach and duodenum, depending on the concentrations of acid and protein in gastric juice, and mixing ratio to gastric juice.

Amylases↗
PubMed1990

Inhibition of tyrosine kinase and epidermal growth factor receptor internalization by lavendustin A methyl ester in cultured A431 cells.

Lavendustin A is a novel microbial secondary metabolite that strongly inhibits tyrosine kinase in vitro. But, since it was found that it did not inhibit tyrosine kinase in situ, possibly because of its poor penetration into the cells, the authors therefore synthesized a methyl ester derivative of lavendustin A. Lavendustin A methyl ester inhibited autophosphorylation and internalization of epidermal growth factor receptor in cultured A431 cells. It also inhibited phosphatidylinositol kinase in vitro and phosphatidylinositol turnover in situ.

Cells, Cultured↗
PubMed1990

[In vitro combined effects of pirarubicin (THP) and various antitumor drugs on human tumor cell lines].

The combined effects of pirarubicin (THP) and various antitumor drugs on HeLa S3 human uterine cervix carcinoma and K562 human myelocytic leukemia cells were determined by enhancement of their cytotoxic activities. The combination of 0.15 microgram/ml THP with cisplatin (CDDP), mitomycin C (MMC), peplomycin (PEP), 5-fluorouracil (5-FU), methotrexate (MTX), enocitabine (BH-AC) or etoposide showed synergistic effects on HeLa S3 cells. Also, the combination of 0.01 microgram/ml THP with CDDP, BH-AC or etoposide showed synergistic effects on K562 cells. Especially, the combined effects of THP with MMC or MTX were remarkable, and the combination under almost all concentrations of MMC or MTX showed synergistic effects on HeLa S3 cells. On the other hand, the combination of adriamycin (ADM) with MMC or MTX did not show such a remarkable effects on HeLa S3 cells.

Antineoplastic Combined Chemotherapy Protocols↗