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Biomedical subjects

T Maeda

Publications and source records attributed to T Maeda.

At least 1,171 records · Page 65Linked to original sources
PubMed1986

[Establishment and characterization of TA-4 producing cell line (OMC-1) originating from a human squamous cell carcinoma of the uterine cervix].

A new human cell line designated OMC-1 was established from a metastatic lesion of Virchow lymph node of a large cell non-keratinizing squamous cell carcinoma of the uterine cervix. OMC-1 was successively subcultured 30 times in about 15 months. The monolayer cultured cells appeared to be epithelial with a pavement-like arrangement and tendency to pile up without contact inhibition. Electronmicroscopy showed desmosomes and well-developed tonofilaments. The population doubling time was 43-70 hours, the saturation density was 1.3-1.7 X 10(5) cells/cm2, the plating efficiency was 23-25% and the mitotic index was 3.3-4.8%. Chromosome studies showed aneuploidy and a modal number of 45. After subcutaneous transplantation into nude mice, the cells grew into solid large cell non-keratinizing squamous cell carcinomas. By the flow cytometric analysis, the phase fractions of the cells was G1 + G0 = 40.1%, S = 24.9% and G2 + M = 35.0%. The OMC-1 cells produced TA-4 in culture media. TA-4 was also demonstrated immunohistochemically in the original tumor tissue, cultured cells and tumors in nude mice.

Animals↗
PubMed1986

[Ischemic colitis after surgery of abdominal aortic aneurysm].

Ischemic colitis following aortic reconstruction for abdominal aortic aneurysm was discussed. The low morbidity rate of postoperative abdominal symptom was recognized significantly when meandering mesenteric artery (MMA) was shown clearly in angiography before surgery. When inferior mesenteric artery (IMA) was patent before surgery, furthermore when IMA was not reconstructed, it is necessary for preventing postoperative ischemic colitis that mean IMA/systemic pressure ratio is above 0.5 or 0.6.

Aged↗
PubMed1986

[Studies on absorption, distribution and excretion of 14C labeled pivaloyloxymethyl (+)-(6R,7R)- 7-[(Z)-2-(2-amino-4-thiazolyl)-2-methoxyiminoacetamido]- 3-[(5-methyl-2H-tetrazol-2-yl)methyl]-8-oxo-5-thia- 1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate (14C-T-2588) in rats and mice].

Absorption, distribution and excretion of T-2588 were studied in rats and mice using (aminothiazole-2-14C) T-2588 and (pivaloyloxymethyl-14C) T-2588. Results are summarized below. The binding rate of 14C-T-2525, an activated form of 14C-T-2588 in vivo, to serum protein was 90 approximately 100% in rats and mice after an oral administration of (aminothiazole-2-14C) T-2588. Blood levels of radioactivity reached to the highest concentration at 1 hour after an oral administration of (aminothiazole-2-14C) T-2588 to rats, and then gradually diminished. After an oral administration of (aminothiazole-2-14C) T-2588 to rats and mice, the highest radioactivity distribution was found in kidney among all the organs except stomach, intestine and bladder. Radioactivity was widely distributed into other organs such as adrenal, lung, liver, heart and pancreas. But little radioactivity was found in the brain. In new born rats, tissue levels of radioactivity were lower and diminished slower than those of adult rats. After an oral administration of (aminothiazole-2-14C) T-2588 to rats and mice, urinary excretion of radioactivity was about 26% and 35% of the dosed radioactivity in rats and mice, respectively, and fecal excretion was about 76% and 63% of the dosed radioactivity in rats and mice, respectively. Urinary and fecal excretion patterns of radioactivity after multiple oral administration of (aminothiazole-2-14C) T-2588 for 7 days to mice were similar to those after a single administration. This result suggests that T-2588 did not accumulate in the body. After an oral administration of (pivaloyloxymethyl-14C) T-2588 to rats and mice, urinary excretion was both about 8% of the dosed radioactivity, and fecal excretion was both about 6%. Then excretion of 14CO2 into respiratory air was about 55% and 66% of the dosed radioactivity in rats and mice, respectively. Biliary excretion was about 6.5% of the dosed radioactivity after an oral administration of (aminothiazole-2-14C) T-2588 to rats. Small amount of radioactivity was secreted to the milk after intravenous administration of (aminothiazole-2-14C) T-2525 to nursing rats. After an administration of (aminothiazole-2-14C) T-2588 to pregnant mice, radioactivity hardly transferred into the fetus.

Administration, Oral↗
PubMed1986

[The autoradiographic studies on the distribution of 14C-labeled pivaloyloxymethyl (+)-(6R,7R)- 7-[(Z)-2-(2-amino-4-thiazolyl)-2-methoxyiminoacetamido]- 3-[(5-methyl-2H-tetrazol-2-yl)methyl]-8-o xo-5-thia- 1-azabicyclo [4.2.0]oct-2-ene-2-carboxylate (14C-T-2588) in mice].

The distribution of T-2588 was studied with whole body autoradiography in normal male mice and pregnant mice using two radioactive T-2588 labeled at the aminothiazole or pivaloyloxymethyl moieties. When (aminothiazole-2-14C) T-2588 was orally administered, the radioactivity was distributed widely to whole tissues except central nervous systems such as brain and spinal cord. In pregnant mice, no detectable radioactivity was present in the fetus. These results suggested that T-2588 was well absorbed and hardly crossed the blood-brain barrier and placenta. At 4 hours after administration, radioactivity was only observed in gastrointestinal tract implying rapid excretion of T-2588. When (pivaloyloxymethyl-14C) T-2588 was orally administered, radioactivity was accumulated to all tissues and fetus. From these results we speculated that formaldehyde formed by hydrolysis at the pivaloyloxymethyl ester and entered the C1-metabolic pathway.

Administration, Oral↗
PubMed1986

[Sensitivity to etoposide in cultured cells from cervical squamous cell carcinoma].

The anti-cancer effect of Etoposide was tested in in vitro in cultures of cells taken from a squamous cell carcinoma of the uterine cervix (SKG-IIIb). Growth inhibition was tested by the regrowth assay method, inhibition of DNA synthesis by the uptake of 3H-thymidine, and morphological changes by the method of Limburg et al. The concentrations of Etoposide used were similar to the blood levels recommended for clinical use. The regrowth assay showed that the effective concentration of Etoposide for 50% cell kill was 7.5 micrograms/ml in 2-hour and 1.0 microgram/ml in 24-hour cultures. The 3H-thymidine uptake test showed that a concentration of 13 micrograms/ml for 2 hours or of 3.5 micrograms/ml for 24 hours resulted in 50% inhibition of DNA synthesis. Morphological changes were much greater in the 2-hour cultures at the higher concentration of Etoposide than in the 24-hour cultures at the lower concentration. Investigation of the drug sensitivity by cell kinetics disclosed prolongation of the cell cycle occurring after 96 hours at 1.0 microgram/ml and inhibition of cell cycle progression occurring after 24 hours at 10.0 micrograms/ml and after 4 or 8 hours at 50.0 mu/ml. Thus, the anti-cancer effect of Etoposide on SKG-IIIb depends on both the concentration and exposure time and is related to its ability to inhibit cell growth and DNA synthesis and to cause morphological changes in the cancer cells.

Carcinoma, Squamous Cell↗
PubMed1985

Effects of adenosine on 45Ca uptake and [3H]acetylcholine release in synaptosomal preparation from guinea-pig ileum myenteric plexus.

The effects of adenosine on acetylcholine (ACh) release and calcium uptake were examined in a synaptosomal fraction prepared from guinea-pig ileum myenteric plexus-longitudinal muscle. A high concentration of potassium (40 mM) and electrical pulses (ES:10Hz) caused a marked increase in the output of [3H]ACh from [3H]choline-preloaded crude synaptosomes. This [3H]ACh output was calcium- and temperature-dependent. Adenosine reduced the high potassium-induced release significantly, and the electrically stimulated release completely. When the preparation was depolarized by high potassium or electrical pulses, the 45Ca uptake by synaptosomes was significantly enhanced. The uptake of 45Ca induced by high potassium was significantly reduced and that induced by electrical stimulation was completely abolished by adenosine. From these results, it may be suggested that adenosine inhibits neurotransmitter release by suppressing the presynaptic influx of calcium ion during depolarization of the cholinergic nerve terminals in guinea-pig ileum.

Acetylcholine↗
PubMed1985

Radioimmunoassay of an analog of luteinizing hormone-releasing hormone, [D-Ser(tBu)]6des-Gly-NH2(10) ethylamide (Buserelin).

A sensitive and specific radioimmunoassay is described for plasma and urinary levels of [D-Ser(tBu)]6des-Gly-NH2(10) ethylamide (buserelin). No appreciable cross-reaction (less than 0.05%) was observed with LH-RH and its analogs other than buserelin fragments (1.6-45%). The sensitivity was 3 pg per tube. At buserelin concentrations of 125, 250 and 500 pg/ml, the intra- and inter-assay coefficients of variation were 7.9, 10.0 and 10.0%, and 19.0, 7.8 and 6.8% respectively. Recovery of buserelin added to plasma was quantitative (62.5 pg/ml, 101.6%; 125 pg/ml, 76.8% and 250 pg/ml, 63.4%). A dose of 5 micrograms buserelin injected subcutaneously into 5 normal male adults, reached a peak plasma level in 45 min (mean value 119.3 +/- 47.3 pg/ml) and remained detectable for at least 4 h. The half disappearance time was 118.8 +/- 26.0 min. Between 9 and 16% of the administered dose was excreted in the urine within 24 h. Buserelin could also be detected in the plasma after intranasal administration of doses of 150, 300 and 450 micrograms. There was a significant difference in the area under the curve (AUC) for plasma levels after subcutaneous injection of 5 micrograms and intranasal administration of 150 micrograms, but not between the AUC values after the three intranasal doses. These results indicate that this method for radioimmunoassay of buserelin is suitable for analyzing the pharmacokinetics and bioavailability of buserelin in man.

Administration, Intranasal↗