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Biomedical subjects

T Kitagawa

Publications and source records attributed to T Kitagawa.

At least 667 records · Page 37Linked to original sources
PubMed1981

Control of passive permeability of Chinese hamster ovary cells by external and intracellular ATP.

External ATP causes passive permeability change in several transformed cells, but not in untransformed cells. We studied the effect of external ATP on the passive permeability of CHO-K1 cells, a transformed clone of Chinese hamster ovary cells. Treatment of the cells with external ATP alone did not produce a permeability change, and this was observed only when a mitochondrial inhibitor, such as rotenone or oligomycin, was present together with ATP. These inhibitors reduced the concentration of intracellular ATP and a permeability change by external ATP was observed when intracellular ATP was decreased more than 70%. This requirement for permeability change of CHO-K1 cells was quite unique, since passive permeability change of other transformed cells so far tested was induced by ATP alone. Treatment of CHO-K1 cells with cyclic AMP analogues increased their sensitivity to external ATP about 2-fold. The roles of external and intracellular ATP in controlling passive permeability are discussed.

Adenosine Triphosphate↗
PubMed1981

Changes in the histologic types of gastric carcinoma in Japan.

The changes in histologic types of gastric carcinoma in Japan in recent years was studied utilizing the 4147 cases surgically resected at the Cancer Institute Hospital, Tokyo, from 1955 to 1974. All carcinomas were classified as either well-differentiated or poorly differentiated, and the ratio of the former to the latter (WPR) was calculated for the first decade (1955-1964) and the second decade (1965-1974). A decline in the WPR was observed, although the difference was not statistically significant. However, when the material was subdivided according to the site of the tumor in the stomach, a decrease in the WPR was markedly visible in the area designated as Fl-area, i.e., a part of the fundic area susceptible to intestinalization. When limited to this area, the difference was statistically significant (P less than 0.05).

Adenocarcinoma↗
PubMed1981

Resonance Raman spectra of bovine adrenal cytochrome P-450SCC.

Resonance Raman spectra were observed for a mitochondria-type cytochrome p-450 (P-450SCC) for the first time. Reduced P-450SCC at pH 7.4 exhibited the V4 line at 1342 cm-1, which is an unusually low frequency compared with an ordinary protohemoprotein but is common to the family of cytochrome P-450, suggesting the coordination of a strong pi-donor such as thiolate anion at the fifth coordination position of the heme iron. The anomaly was preserved for the CO-complex of the reduced form. The V10 line of oxidized P-450SCC with a substrate was observed at 1617 cm-1. This frequency and those of other structure-sensitive bands implied that the heme iron of oxidized P-450SCC adopts the hexa-coordinate high-spin structure, in contrast with the high-spin type cytochrome P-450 purified from phenobarbital- or 3-methylcholanthrene-treated rabbit liver microsomes which presumably have a penta-coordinate structure. In the presence of 20alpha-hydroxycholesterol, oxidized P-450SCC gave the V10 line at 1637 cm-1, i.e., at a frequency similar to that of low-spin type cytochrome P-450. The alkaline-denatured P-420SCC preparation in the presence of both dithiothreitol and EDTA, but not the P-450SCC gave the V10 line at 1637 cm-1, i.e., at a frequency similar to that of low-spin type cytochrome P-450. The alkaline-denatured P-420SCC preparation in the presence of both dithiothreitol and EDTA, but not the P-450SCC.

Adrenal Cortex↗
PubMed1981

Inactivation of pyroglutamyl aminopeptidase by L-pyroglutamyl chloromethyl ketone.

A chloromethyl ketone derivative of pyroglutamic acid was newly synthesized and its reactivity with bacterial pyroglutamyl aminopeptidase (L-pyroglutamyl-peptide hydrolas, EC 3.4.11.8) as an affinity labelling reagent was examined. The compound was found to inactivate the enzyme markedly and rapidly at very low concentrations, though the enzyme was resistant to N-tosyl-phenylalanyl chloromethyl ketone. The rate of the enzyme inactivation by pyroglutamyl chloromethyl ketone was retarded in the presence of a poor substrate, pyroglutamyl valine. The enzyme inactivated by treating with p-chloromercuribenzoate failed to react with pyroglutamyl chloromethyl ketone. These results strongly suggest an active site-directed mechanism for the enzyme inactivation by pyroglutamyl chloromethyl ketone. This compound was shown to be useful as a titrant for the catalytically active protein of pyroglutamyl aminopeptidase.

Amino Acid Chloromethyl Ketones↗
PubMed1981

Novel preparation method of immunogen for hydrophobic hapten, enzyme immunoassay for daunomycin and adriamycin.

The present study was undertaken to develop a novel method of preparing a hydrophobic hapten as immunogen. The anticancer drug, daunomycin (DM) was used as prototype and coupled to mercaptosuccinylated bovine serum albumin (MS, BSA) with N-(gamma-maleimidobutyryloxy)succinimide (GMBS). Injection of rabbits with a conjugate (DM-GMBS-MS.BSA) which contained 7.3 DM per BSA molecule produced good levels of anti-DM antibody which was detected by the reaction of diluted antiserum with beta-D-galactosidase-labeled DM. beta-D-galactosidase-labeled DM was used to develop a double antibody enzyme immunoassay for DM and for the DM homologue adriamycin (AM) which reproducibly detected as little as 1 pmole of either drug. A variety of commonly used other anticancer drugs were tested and had little reactivity in this immunoassay. These studies indicate that the anti-DM serum produced is highly specific.

Animals↗
PubMed1981

Inactivation of pyroglutamyl aminopeptidase by N alpha-carbobenzoxy-L-pyroglutamyl chloromethyl ketone.

Pyroglutamyl aminopeptidase [pyrrolidone-carboxylate peptidase: EC 3.4.11.8] from Bacillus amyloliquefaciens was inactivated rapidly and irreversibly by N alpha-carbobenzoxy-L-pyroglutamyl chloromethyl ketone (Z-PGCK). The second-order rate constant of the inactivation was 1.1 x 10(5) M-1.s-1, a value which is comparable to that of the clostripain-TLCK reaction. The D-isomer of this chloromethyl ketone derivative was almost inert toward the enzyme under the same conditions. The inactivation reaction was prevented by the presence of a poor substrate, pyroglutamyl-valine. The PCMB-inactivated enzyme, that was reversibly reactivated by 2-mercaptoethanol, failed to react with Z-PGCK. These results suggest that this chloromethyl ketone derivative reacts as an affinity label, presumably with the active site cysteinyl residue of the enzyme, as was reported for L-pyroglutamyl chloromethyl ketone.

Affinity Labels↗
PubMed1981

A clinical and electroencephalographical follow-up study for more than 10 years in patients with epilepsy.

A clinical and electroencephalographical follow-up study of 10 to 18 years was conducted on 147 patients with epilepsy. Generalized epilepsy was prognostically favorable, but petit mal absence with grand mal was not always good clinically and electroencephalographically as generally accepted. Paroxysmal discharges found in the initial EEGs tended to become more localized in the final EEGs recorded at least more than 10 years later. The migration of spike foci and bilateral independent spikes were found in many patients. Prognostically the EEG background was more important. Fourteen and six-per-second positive spikes and 6Hz spike and wave phantoms had an age dependence as well as 3 Hz spike and wave complexes and these discharges were regarded as prognostically the favorable patterns.

Adolescent↗
PubMed1981

Detection of Residual penicillin in milk by sensitive enzyme immunoassay.

A convenient and precise method by an application of a highly sensitive enzyme immunoassay of penicillin to detect the veterinary penicillin residue in milk was studied. The procedures of the assay to detect more than 0.01 microgram/ml of ampicillin in milk were developed. Five commercial milk samples were tested by the assay procedure, and no veterinary ampicillin residue was detected in any of them.

Ampicillin↗
PubMed1981

Enzyme immunoassay of neocarzinostatin using beta-galactosidase as label.

A novel convenient procedure was introduced for enzyme labelling of neocarzinostatin (NCS) with beta-D-galactosidase using a new hetero-bifunctional reagent N-(gamma-maleimidobutyryloxy) succinimide (GMBS). With the enzyme labelled NCS and a rabbit anti-NCS serum which was elicited in a rabbit immunized with NCS in complete Freund's adjuvant, a highly sensitive enzyme immunoassay which can quantify a femto mol order NCS was developed. Accuracy and precision of the assay as well as a comparison with the immunodiffussion method were studied with satisfactory results. This enzyme immunoassay of NCS was applicable to monitoring serum NCS levels of patients in clinical treatment of the antitumor agent.

Antibiotics, Antineoplastic↗
PubMed1981

A comparison of the differential effects of nitroglycerin, nifedipine and papaverine on contractures induced in vascular and intestinal smooth muscle by potassium and lanthanum.

To elucidate the mechanisms of smooth muscle relaxant effects of nitroglycerin, the effects of this substance on the potassium contracture (K+-contracture) and the lanthanum-induced contracture (La3+-contracture) were studied using smooth muscle preparations of the canine coronary artery and colon and the findings compared with the effects of nifedipine, a representative calcium antagonistic vasodilator. The effects of papaverine, a prototype smooth muscle relaxant, were also studied. La3+-contracture was induced in a calcium-free environment with the addition of lanthanum, an effective blocker of calcium influx. In the coronary artery, nitroglycerin produced a relaxation both of the La3+-contracture not K-contracture in the colon was affected. Nifedipine did not relax the La3+-contracture in a range of doses at which K+-contracture of both types of smooth muscles was relaxed. Papaverine produced a relaxation of La3+-contracture as well as K+-contracture, in both types of smooth muscles. Unlike the mechanism related to the relaxant effects of nifedipine, which is generally admitted to be an inhibition of calcium influx, the relaxant effect of nitroglycerin was attribute to the suppression of calcium release from the intracellular store sites and/or stimulation of calcium uptake into the intracellular store-sites. Papaverine was assumed to produce a relaxation through augmentation of the calcium binding to the intercellular store sites for calcium as well as through inhibition of the calcium influx.

Animals↗
PubMed1981

Treatment of esophageal cancer with high dose rate intracavitary irradiation.

Fifteen patients with esophageal cancer were treated with high dose rate intracavitary irradiation from a small radioactive source. The apparatus used for the intracavitary irradiation consisted of a remote-control intracavitary irradiation apparatus with small high intensity source (Ralstron, Shimazu Co.) and a transfer tube of radioactive source. Since the field size of irradiation was various, the most suitable program was set up at the depth of 0.5 cm from the inner surface of the esophagus. 13 fresh cases were treated with high dose rate intracavitary irradiation of 1000-2750 rads (0.5 cm below the inner surface) after external irradiation of ca. 5000 rads with Linac x-ray. As a result, 7 cases survived 1 year and 1 case 2 years. Local recurrence was seen in 5 out of 7 cases surviving 1 year. 2 recurrence cases after radical external irradiation showed improvement on x-ray picture through intracavitary irradiation.

Aged↗
PubMed1981

Solid phase enzyme immunoassay of tobramycin.

We have developed a competitive enzyme immunoassay (EIA) using co-polymer of styrene and maleate as the solid phase and glutaraldehyde for binding of the antibody to the solid phase. This assay showed a striking efficacy in its use for the assay of tobramycin (TOB). Furthermore, the pharmacokinetics of TOB were studied in six healthy male volunteers after the administration of 60- or 90-mg doses intramuscularly.

Adult↗
PubMed1981

Enzyme immunoassay for pepleomycin, a new bleomycin analog.

An antibody directed toward pepleomycin, a new antitumor antibiotic related structurally to bleomycin, has been produced in rabbits by immunization with a pepleomycin-protein conjugate which was prepared by a novel procedure of coupling pepleomycin to mercaptosuccinylated bovine serum albumin using N-(gamma-maleimidobutyryloxy)succinimide as a coupling agent. The antiserum was monospecific to pepleomycin and showed almost no cross-reactivity with a variety of other bleomycin analogs. An enzyme immunoassay for pepleomycin has been developed utilizing this antiserum and beta-D-galactosidase-labeled pepleomycin. The lower limit of detection by this assay, which involves a double antibody technique for the separation of antibody-bound and free antigen, was 50 pg of pepleomycin per tube. Using this assay, drug levels were easily determined in blood and urine of rabbits following administration of pepleomycin in a single dose of 1.2 mg/kg i.v. This assay is also suitable for measuring pepleomycin in the presence of other drugs since the assay is not significantly affected by any other antineoplastic agents tested. Since pepleomycin is now undergoing clinical trial, the enzyme immunoassay of the drug will be a valuable tool in clinical pharmacological studies.

Animals↗