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Biomedical subjects

T Takeuchi

Publications and source records attributed to T Takeuchi.

At least 1,693 records · Page 94Linked to original sources
PubMed1985

In vitro inhibition of Giardia lamblia and Trichomonas vaginalis growth by bithionol, dichlorophene, and hexachlorophene.

Bithionol, dichlorophene, and hexachlorophene, which are used in treating some helminthic infections, killed trophozoites of Giardia lamblia and Trichomonas vaginalis in modified BI-S-33 and Asami media, respectively. Virtually all G. lamblia and T. vaginalis cells were killed within 24 h with a 0.42 mM concentration of these compounds, except that 0.93 mM dichlorophene was required for sterilizing T. vaginalis in the same period. In modified BI-S-33 and Asami media from which bovine and human sera were omitted, respectively, the inhibitory actions of the compounds against in vitro growth of these protozoa were significantly enhanced. Trophozoites of G. lamblia and T. vaginalis could be killed in shorter than 10 min with 0.074 mM dichlorophene and 0.0025 mM hexachlorophene, respectively, in serum-free media. G. lamblia, which was incubated in the complete medium containing dichlorophene, showed a characteristic swelling of the ventral side which led to disruption of the parasite, whereas bithionol caused a thin crack in the cytoplasm of T. vaginalis incubated in Asami medium. The crack appeared to enlarge and result in vacuolization of T. vaginalis. These observations suggest that bithionol, dichlorophene, and hexachlorophene merit further evaluation to ascertain whether they are useful for treatment of giardiasis and trichomoniasis.

Animals↗
PubMed1985

A follow-up study of throat carriers of streptococci among schoolchildren in Otsu City.

Studies on the prevalence of beta-hemolytic streptococci in throats among primary school children were performed in Otsu City. In the first study, evidence of streptococcal infections was investigated in 41373 children of first grade of all primary schools for the 13 years from 1970 to 1982. An average of 12.2% of the strains isolated belonged to group A. The order of frequency of the other Groups was B, C and G respectively. The most predominant type of Group A streptococci was Type 12. In the second study, evidence of streptococcal infections was investigated in 87 children of the first grade of one primary school for the 5 years from 1977 to 1982. Throat cultures were repeated four times a year during the period of five years. Entire negative throat cultures over a 5-year period were observed in only 4 children. The prevalence of beta-hemolytic streptococci and Group A streptococci in throats were higher than those observed in the first study. The predominant types of Group A were Types 1, 6 and 28, although the relative predominance of these Types varied at different times during 5 years. High serum ASO titers were observed in the children who harbored Type 6 strains of Group A streptococci in throats. In 5 children Group A streptococci were frequently recovered from throats during the study period, and the same type of strains of Group A streptococci were isolated repeatedly.

Child↗
PubMed1985

[Contribution of prostaglandins to the activity of guinea-pig phrenic and chicken esophageal parasympathetic nerves].

In order to clarify the role of prostaglandins (PGs) in the activity of cholinergic neurones other than the ileal myenteric plexus, the effects of indomethacin (IND) and PGE2 on the contractile responses and the release of acetylcholine (ACh) induced by electrical stimulation were investigated in isolated guinea-pig phrenic nerve-diaphragm and chicken parasympathetically innervated oesophagus preparations. In the guinea-pig phrenic nerve-diaphragm preparations, IND at 56 microM did not affect the twitch responses induced by direct or indirect electrical stimulation. PGE2 at 1 microgram/ml augmented the twitch responses induced by direct or indirect stimulation of submaximal, but not of supramaximal intensity. The amounts of ACh released from the phrenic nerve by electrical stimulation were unaffected by IND (56 microM). PGE2 (0.01-1 microgram/ml) inhibited the ACh release by the nerve stimulation of high frequency (50 Hz) in a concentration-dependent manner. The inhibitory effect of PGE2 was less clear on the ACh release by lower frequency (1 Hz). Neither IND nor PGE2 affected the ACh release induced by 40 mM-K+. In the chicken parasympathetically innervated oesophagus preparation, IND (2.8-5.6 5.6 microM) augmented the twitch responses induced by the nerve stimulation at a frequency of 0.017 Hz, but not those produced by train pulse (5 sec at a frequency of 1 or 10 Hz). This augmentation was reversed by the application of PGE2 at 10 ng/ml. PGE2 at 10 ng/ml produced a transient inhibition of the twitch responses induced by 0.017 Hz or train pulses.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1985

Efficient culturing of human melanocytes from suction blisters.

The culturing of normal human melanocytes from the roof of suction blisters of adult oriental volunteers was carried out. Since the epidermal roofs of blisters did not contain any fibroblasts, and since keratinocytes did not attach to the culture dishes in the presence of PMA (phorbol 12-myristate 13-acetate), many melanocytes were obtained which grew well in the presence of PMA. This method is a very simple and easy way to establish pure melanocyte cultures.

Adult↗
PubMed1985

Saquayamycins, new aquayamycin-group antibiotics.

From the culture broth of Streptomyces nodosus MH190-16F3, four new antibiotics have been isolated, and named saquayamycins A, B, C and D. The compounds are glycosides of aquayamycin, and among aquayamycin-group antibiotics they are most closely related to P-1894B (vineomycin A1). All saquayamycins act on Gram-positive bacteria and inhibit the growth of adriamycin-sensitive and adriamycin-resistant P388 leukemia cells.

Animals↗
PubMed1985

Antitumor activities of (2"R)-4'-O-tetrahydropyranyl-adriamycin (THP) and its combination with other antitumor agents on murine tumors.

(2''R)-4'-O-Tetrahydropyranyladriamycin (THP) is a new derivative of doxorubicin (adriamycin, ADM). The concentrations of THP and ADM required to inhibit by 50% the growth of a cultured L1210 cells was 0.003 microgram/ml and 0.016 microgram/ml, respectively. Various therapeutic designs of combinations of THP with other antitumor agents were investigated in vivo using the L1210 murine leukemia. The combination of THP with cytosine arabinoside (Ara-C), cyclocytidine hydrochloride (Cyclo-C), 6-mercaptopurine (6-MP) and cyclophosphamide (EX) showed a great effectiveness following daily intraperitoneal treatment from days 1 to 10. High therapeutic effects were also obtained with the combinations of THP with Ara-C, Cyclo-C, vincristine (VCR) and EX following intravenous combination therapy one day following implantation of L1210 leukemia. Schedule dependency and its therapeutic efficacy of THP were examined. THP showed almost the same antitumor activity on the solid-type sarcoma-180 or solid-type Ehrlich carcinoma as ADM by intraperitoneal or intravenous treatment. THP showed some superior activity to ADM in the advanced stage of L1210 leukemia. High antitumor activity of THP on murine leukemia L1210 has been reported by Tsuruo et al. (Cancer Res. 42: 1462-1467, 1982) and was also confirmed. THP gave many mice cures, especially in the intravenous treatment.

Animals↗
PubMed1985

Isolation and characterization of terpentecin, a new antitumor antibiotic.

A new antitumor antibiotic, terpentecin was isolated from the culture broth of strain MF730-N6. Strain MF730-N6, isolated from soil, was found to belong to the genus Kitasatosporia. The antibiotic was extracted with chloroform, purified by column chromatography using silica gel and Diaion HP-20 successively, and finally purified by high performance reverse-phase thin layer chromatography. The molecular formula of terpentecin was determined to be C20H28O6 (molecular weight, 364). The antibiotic inhibited the growth of Gram-positive and Gram-negative bacteria, and prolonged the survival period of mice bearing leukemia L-1210, P388 and Ehrlich ascites carcinoma.

Actinomycetales↗
PubMed1985

Vanoxonin, a new inhibitor of thymidylate synthetase. II. Structure determination and total synthesis.

Acid hydrolysis of vanoxonin yielded one mol each of 2,3-dihydroxybenzoic acid, L-threonine, L-N omega-hydroxyornithine. Presence of acetyl group in vanoxonin was suggested by the 1H NMR. Periodate oxidation of vanoxonin liberated one mol of acetic acid suggesting that the acetyl group bound to the omega-nitrogen of N omega-hydroxyornithine. The sequence of three components was determined to be L-N-(2,3-dihydroxybenzoyl)threonyl-L-(N omega-acetyl-N omega-hydroxy)ornithine by mass spectrometric analysis. This structure was confirmed by the total synthesis of vanoxonin.

Dipeptides↗
PubMed1985

Vanoxonin, a new inhibitor of thymidylate synthetase. III. Inhibition of thymidylate synthetase by vanoxonin-vanadium complex.

Quinquevalent vanadium complex with two mol of vanoxonin ligated by the two catechols was shown to be the active structure for inhibition of thymidylate synthetase. The catechol group of vanoxonin as the essential moiety for the inhibition of enzyme was further confirmed by studies of structure-activity relationships using the enzyme obtained from Ehrlich ascites carcinoma cells of mice. Vanoxonin-vanadium complex showed competitive inhibition with respect to deoxyuridylic acid but uncompetitive to 5,10-methylenetetrahydrofolate.

Dipeptides↗
PubMed1985

Enhancement of antitumor effect of cytotoxic agents by bestatin.

Bestatin enhanced the antitumor effects of mitomycin C, 5-fluorouracil and cis-dichlorodiammineplatinum against a syngeneic solid tumor of colon adenocarcinoma 26 in BALB/c mice. The enhancement was dependent on administration schedule. Bestatin administration after treatment with the cytotoxic agents was more effective than that made before the treatment.

Adenocarcinoma↗