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Biomedical subjects

T Sado

Publications and source records attributed to T Sado.

At least 109 records · Page 6Linked to original sources
PubMed1978

[Quarantine and health control of the squirrel monkey (Saimiri sciureus) (author's transl)].

A total of two hundreds and seventy squirrel monkeys (Saimiri sciureus) of both sexes were imported from South America through an animal dealer of the U. S. A. in eight lots from May, 1973 to July, 1974. They were investigated for the presence of the parasites for a maximum of fifteen months including nine weeks of quarantine period from the time of import. The mortality rate before or immediately after arrival at our laboratory reached 56.7% in the first two lots. This, however, could be reduced later to 4.8% by improving some conditions of transportation. Bacteriological surveys revealed no shigella or salmonella infections during the quarantine period. No tuberculin positive reactors were also detected. Filarial infestations seemed to be common in this species; about 45.5% had adult worms in the peritoneal cavity and about 65% harbored microfilaria in the peripheral blood. Acanthocephla was also found in a high rate in the lower alimentary tracts. It has been suggested that the worms disappear in fifteen months by keeping animals in the intermediate host-free circumstances. The sarcocyst was found in the femoral muscle of 7 (18.9%) of 37 animals examined histologically.

Acanthocephala↗
PubMed1977

Absorption, excretion and metabolism of a new dihydropyridine diester cerebral vasodilator in rats and dogs.

1. After oral administration of [14C]dihydropyridine diester, the plasma concn. of radioactivity was similar in rats and dogs, reaching a maximum at 0-5 to 1 h and decreasing with a half life of about 3-5 h. The plasma concn. of unmetabolized drug in dogs was 10 times higher than in rats. Radioactivity in rat tissue was high in liver, kidney and lung after both oral and intravenous administration. 2. In both species, 66-72% of radioactivity was excreted in faeces and 23-29% in urine in 48 h, regardless of the route of administration. Biliary excretion in rats after oral dosage amounted to 65%. 3. Eight metabolites were identified from urine of dogs and rats. They were derived from one or several of the following pathways: I, debenzylation of the N-benzyl-N-methylaminoethyl side chain; II, reduction of the 3-nitro group on the phenyl substituent; III, oxidation of the 1,4-dihydropyridine ring to the corresponding pyridine; IV, oxidative removal of the N-benzyl-N-methylamino group yielding a carboxylic acid; V, hydrolysis of the N-benzyl-N-methylamino-ethyl ester to the corresponding carboxylic acid; VI, hydroxylation of the 2-methyl group of the 1,4-dihydropyridine ring to hydroxymethyl.

Animals↗
PubMed1977

Lack of toxicity of chenodeoxycholic acid in the squirrel monkey.

The toxicity of chenodeoxycholic acid was studied in squirrel monkeys of both sexes. The drug was orally administered to five groups of 26 animals each at a daily dose of 0, 10, 20, 40, and 80 mg per kg, respectively, for a maximum of 52 weeks. No clinical symptoms that could suggest drug toxicity were observed. All laboratory studies, including liver function tests, were within normal limits. The proportion of lithocholic acid in biliary acids remained unchanged, whereas that of chenodeoxycholic acid was dose-dependently increased. No histopathological changes considered to be attributable to drug administration were observed.

Administration, Oral↗
PubMed1976

Vasodilator profile of a new 1,4-dihydropyridine derivative, 2,6-dimethyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-[2-(N-benzyl-N-methylamino)]-ethyl ester 5-methyl ester hydrochloride (YC-93).

A new 1,4-dihydropyridine derivative, 2,6-dimethyl-4-(3-nitrophenyl)-4,4-dihydropyridine-3,5-dicarboxylic acid 3-[2-(N-benzyl-N-methylamino)]-ethyl ester 5-methyl ester hydrochloride (YC-93), when i.v. injected into anesthetized dogs, exhibited not only a greated vasodilation in both cerebral and coronary than in femoral vessels, but also about 100 to 300 times higher potency as well as longer durability than any of reference drugs such as isoxsupurine, papaverine and cinnarizine. YC-93 was also effective in vasodilation by i.m. and i.d. administration. When administered into vertebral and coronary arteries, YC-93 caused vasodilation at the doses that did not affect systemic blood pressure. YC-93 did not potentiate the vasodilator effect of adenosine, and vasodilation by YC-93 was influenced by neither propranolol, atropine, diphenhydramine nor aminophylline. Acute toxicity (LD50) of YC-93 was almost the same as that of papaverine in mice and rats. Thus, YC-93 is a potent bu low-toxic vasodilator agent acting preferentially and perhaps directly on cerebral and coronary vascular beds and is well absorbed from gastrointestinal tract into blood stream.

Animals↗
PubMed1975

Determination of a new cerebral vasodilator 2,6-dimethyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-[2-(N-benzyl-N-methylamino)]-ethyl ester 5-methyl ester hydrochloride (YC-93) in plasma by electron capture gas chromatography.

A highly sensitive method for the quantitative determination of 2,6-dimethyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-[2-(N-benzyl-N-methylamino)]-ethyl ester 5-methyl ester hydrochloride (YC-93) in plasma is described. After extraction, YC-93 was oxidized to a pyridine analogue with nitrous acid and detected by electron capture gas chromatography. The sensitivity was 2-3 ng/ml, which is sufficient to determine plasma concentrations of YC-93 after oral administration of clinical doses to humans.

Chromatography, Gas↗
PubMed1975

Histocompatibility and T-B cell cooperation in mouse radiation chimeras.

Cooperative interaction between histocompatible as well as histoincompatible T and B cells in vivo was studied with B cell-bearing syngeneic radiation chimeras receiving syngeneic, semiallogeneic, or allogeneic A and T cells in various combinations. The results indicated the following: i) Histoincompatible T and B cells normally did not cooperate successfully for generation of antibody-forming cells. ii) Semiallogeneic (C3BF1) T cells cooperated successfully with parent-type (C3H) B cells developed in parent-type syngeneic chimeras (C3H/C3H), whereas parent-type (C3H as well as C57BL) T cells failed to cooperate with F1 (BC3F1) B cells developed in F1 syngeneic chimeras (BC3F1/BC3F1). iii) T cells obtained from C57BL/C3H or C57BL/C3BF1 chimeras, which were most likely donor (C57BL)- derived, cooperated successfully with C3H-derived B cells developed in C3H/C3H chimeras. iv) Evidence was obtained suggesting that stimulation of antibody response by allogeneic effect in the absence of syngeneic or semisyngeneic helper T cells did not take place in this experimental system. v) With the use of congenic resistant strains, it was shown that alloantigens controlled by H-2 loci, in particular by the K-I region of this gene complex, constituted the barrier of cooperative interaction between histoincompatible T and B cells. vi) Cooperation between H-2 compatible, non-syngeneic T and B cells was also disturbed in varying degrees depending on the strain combinations, thus indicating that cell surface antigens controlled by non-H-2 loci also had a significant role for the cooperative interaction between T and B cells. Problems associated with these findings were discussed.

Animals↗
PubMed1975

[Absorption, distribution and excretion of 14C-josamycin and 14C-josamycin propionate in rats (author's transl)].

Abosrption, distribution and excretion of 14C-josamycin (JM) and 14C-josamycin propionate (JM-P) were studied in rats by measuring both antibacterial activity and radioactivity. 1. In antibacterial activity, plasma and tissue concentrations of JM-P showed a similar tendency to those of JM. Those concentrations of JM reached a peak at 1 hour after administration with a subsequent rapid decrease, while the peak level of JM-P appeared 2 approximately 4 hours after administration and then fell down very slowly. 2. In radioactivity, oral administration of JM-P rapidly produced a very high plasma and tissue concentrations which were in lung, liver, kidney and spleen more than twice those of JM. These results showed that when given orally, JM-P is well absorbed with distributions at high concentrations especially in lung, liver, and kidney and spleen. 3. The ratios of bioactivity/radioactivity in JM administration were the highest in lung and the lowest in liver at 1 hour after. But those of JM-P were generally much lower than those of JM because of higher distribution of JM-P radioactivity into tissues. 4. Four days after oral administration of JM and JM-P, 23.1% and 21.8% of the given radioactivity were recovered respectively from urine. However, the antibacterial activities recovered were 0.40% for JM and 0.65% for JM-P. 5. Biliary recoveries of JM and JM-P were 17.2% and 12.1% of administered radioactivity 2 days after oral administration. On the other hand, 0.47% of JM and 0.17% of JM-P were excreted into bile as antibacterial activity. These results showed that JM and JM-P were excreted into rat urine and bile as some metabolites with less biological activity. 6. The amounts of JM and JM-P recovered from feces were 75.7% and 60.2%, respectively, of the orally given radioactivity. The amount of radioactivity recovered from expiration air was about 1% of either orally given JM or JM-P.

Animals↗
PubMed1975

The radiosensitivity of T and B lymphocytes in mice.

The radiosensitivity of T and B lymphocytes in spleens of specific pathogen-free C3Hf/HeMs male mice was studied by the direct and indirect immunofluorescence technique. It was found that the radiobiological parameters characterizing the survival curve of Bpsi lymphocytes were DO = 200 R and n = 1-00. The T lymphocytes, on the other hand, were shown to consist of two distinct subpopulations with respect to their radiosensitivity. The radiobiological parameters of the radiosensitive fraction of T lymphocytes were Dq = 185 R, DO =195 R and n = 2-50. The DO value of the radioresistant T lymphocyte subpopulation was practically unmeasurable. It was estimated that approximately 8 per cent of the T lymphocytes present in the spleen of normal C3Hf mice belonged to this radioresistant subpopulation.

Animals↗