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Biomedical subjects

K Tsuchiya

Publications and source records attributed to K Tsuchiya.

At least 649 records · Page 36Linked to original sources

Thermally-induced cutaneous sympathetic activity related to blood flow through capillaries and arteriovenous anastomoses.

In the ears of anaesthetized rabbits cutaneous efferent sympathetic nerve activity (SkNA) and blood flow (Q) to capillaries have been measured during various thermal treatments. Warming the spinal cord or skin of the body midside caused a marked decrease in SkNA but capillary Q increased only slightly. Exposure to a warm environment or localized warming of the ear alone induced either a decrease, an increase, or no change in SkNA, but capillary Q always increased markedly. The usual slight increase in capillary Q during spinal warming, was abolished by preventing the usual marked increase in skin temperature. When the spinal cord of the conscious rat was warmed, a marked increase in temperature of the tail (which contains arteriovenous anastomoses, AVA's) indicated dilatation, whereas there was no change in ear temperature (where there are no AVA's). When these results are considered together with recently defined differential influences of reflex and direct effects of temperature on blood flow through cutaneous AVA's and capillaries, it is concluded: (1) That thermally-induced reflex changes in skin blood flow are mediated via sympathetic nervous action on AVA's; (2) Changes in blood flow evoked by direct heating take place through the capillaries, not the AVA's, quite independently of SkNA.

Animals↗

SCE-129, antipseudomonal cephalosporin: in vitro and in vivo antibacterial activities.

SCE-129 [3-(4-carbamoyl-1-pyridiniomethyl)-7beta-(d-alpha-sulfophenylacetamido)-ceph-3-em-4-carboxylate monosodium salt], a new semisynthetic cephalosporin, shows potent in vitro antibacterial activities against Pseudomonas aeruginosa and some gram-positive bacteria, whereas it shows lower activity against many gram-negative rods. Against clinical isolates of P. aeruginosa this cephalosporin exhibited higher activity than did carbenicillin, and against the strains of Staphylococcus aureus, SCE-129 had similar activity to carbenicillin. Variations in pH, addition of horse serum, and type of growth medium had no significant effects on the activity of the cephalosporin; however, the inoculum size had some effect on the activity. SCE-129 is an effective bactericidal agent against P. aeruginosa and S. aureus. The protective effects of SCE-129 in mice infected with P. aeruginosa and S. aureus were more potent than those of carbenicillin. The protective effects of SCE-129 on Pseudomonas infection in mice varied according to the dosage schedule and the challenge dose. In a multiple dose schedule, a smaller amount of SCE-129 was necessary than that in a single dose schedule. The effects of SCE-129 after subcutaneous or intraperitoneal administration were more potent than were those by intravenous administration. No protective effect was observed by oral administration.

Animals↗

Comparative in vitro activities of SCE-129, sulbenicillin, gentamicin, and dibekacin against Pseudomonas.

Against sulbenicillin- and gentamicin-susceptible strains of Pseudomonas aeruginosa, SCE-129 was about 10 times more active than sulbenicillin and had a similar activity to gentamicin and dibekacin. Sulbenicillin-resistant strains of P. aeruginosa were moderately resistant to SCE-129, whether these strains were gentamicin-resistant or not. Gentamicin-resistant strains of P. aeruginosa were resistant to dibekacin but not to SCE-129. Against P. maltophilia, the minimum inhibitory concentration of SCE-129 resembled those of sulbenicillin, gentamicin, and dibekacin. Most strains of P. cepacia were moderately resistant to SCE-129 and sulbenicillin and highly resistant to gentamicin and dibekacin.

Cefsulodin↗

Comparative in vivo activities of cefsulodin, sulbenicillin, and gentamicin against Pseudomonas aeruginosa.

The in vivo activities of cefsulodin, sulbenicillin, and gentamicin were compared in mice infected intraperitoneally with Pseudomonas aeruginosa. In mice infected with sulbenicillin- and gentamicin-susceptible strains, cefsulodin was about 12 to 60 times more active than sulbenicillin and had an activity similar to gentamicin. In mice, the activity of cefsulodin was independent whether the strains were resistant to gentamicin or not, but it was considerably affected by resistance of the strains to sulbenicillin.

Animals↗

SCE-963, a new broad-spectrum cephalosporin: in vitro and in vivo antibacterial activities.

SCE-963 {7beta-[2-(2-aminothiazol-4-yl)acetamido]-3-[({1-(2-dimethylaminoethyl)- 1H-tetrazol-5-yl}thio)methyl]-ceph-3-em-4-carboxylic acid}, a new semisynthetic cephalosporin, showed excellent antibacterial activity against gram-positive and gram-negative bacteria, including Haemophilus influenzae, indole-positive Proteus, Enterobacter species, and Citrobacter freundii. The minimum inhibitory concentrations of SCE-963 against most strains of clinically isolated Escherichia coli, Klebsiella pneumoniae, H. influenzae, and Proteus mirabilis were within the range of 0.2 to 0.78 mug/ml. These activities were about 10 times more potent than those of cefazolin, cephaloridine, and cephalothin. Variations in pH, addition of horse serum, and type of growth medium had no significant effect on the activity of the cephalosporin, but the inoculum size elicited a considerable effect on the activity of beta-lactamase-producing strains of bacteria. SCE-963 exerted bactericidal and bacteriolytic effects on Staphylococcus aureus and E. coli. The pronounced in vitro activity was reflected in the remarkable protection in mice infected with a wide range of gram-negative bacteria, such as E. coli, K. pneumoniae, P. mirabilis, Proteus vulgaris, Proteus morganii, and Proteus rettgeri. The protective effects of SCE-963 in mice infected with E. coli, K. pneumoniae, and P. vulgaris varied according to the challenge dose. The activity of SCE-963 was far more potent when the drug was administered parenterally rather than orally.

Animals↗

Production of trypsin inhibitor by a Cephalosporium sp.

Conditions for the production of the trypsin inhibitor from Cephalosporium sp. KM 388 were investigated. Polypeptone-meat extract-glucose medium supported excellent production of the trypsin inhibitor. In this medium, polypeptone and meat extract were utilized both as carbon and nitrogen sources and as limiting substrates for the cell growth. Glucose was consumed during the stationary growth phase and prevented the disappearance of inhibitor activity. Cephalosporium sp. KM 388 grew at a rate of a first-order reaction for the cell concentrations. Trypsin inhibitor production paralleled cell growth. At 27 degrees C the maximum specific rates of growth and inhibitor production were 0.14 h-1 and 2.1 U of inhibitor/h per mg of cell, respectively. The production rate and the maximum yield of the inhibitor were increased 1.5- and 1.2-fold, respectively, when the initial pH 6.3 was maintained throughout the fermentation.

Acremonium↗

Experimental urinary tract infection with Pseudomonas aeruginosa in mice.

Urinary tract infection with Pseudomonas aeruginosa was induced in mice by transurethral inoculation of the organism into the bladder, followed by urethral obstruction for 6 h. The infection was mostly localized in the urinary organs. P. aeruginosa P9 was selected as the challenge organism from 10 laboratory strains of P. aeruginosa. After the inoculation of 10(7) colony-forming units of P. aeruginosa P9, transient bacteremia was observed in some of the mice from 6 h to 1 day after the inoculation. The number of organisms in the bladder tissue gradually decreased, whereas that in the kidneys increased to levels of 10(6) to 10(7) colony-forming units in 3 days, and these levels remained up to 2 weeks after the inoculation. The organisms gradually disappeared thereafter, and spontaneous recovery took place. The organisms could be recovered from the kidneys of 95% of the mice, and the gross lesions in the kidneys were observed in 77% of the mice 1 week after inoculation. The method developed here is simple and may be useful in the study of urinary tract infections due to P. aeruginosa and other species of bacteria.20

Animals↗

Interrelationships among zinc, copper, lead, and cadmium in food, feces, and organs of humans.

Concentrations of zinc, copper, lead, and cadmium were determined in 20 samples of food collected over a period of 20 days, 221 samples of feces collected over a period of 5 days from 19 males, 17 females, and 11 children and 85 samples each of renal cortex and liver from autopsied human cadavers in order to investigate the relationships among the four metals and among the various martices. In food the highest correlation was observed between copper and zinc (0.34). In feces the highest correlation was also between copper and zinc (0.45). In the highest correlation between cadmium and zinc (0.33), but that in the renal cortex was between copper and cadmium (0.52). These findings suggest that the relationships among the concentrations of the four metals in food and feces are almost equal to each other, but differ greatly from the concentrations in human organs due to the differing metabolic actions of the metals once they are absorbed into the body. In addition, it was observed that zinc and cadmium concentrations in the renal cortex increase with age, but copper and lead concentrations do not show much variation with age.

Aging↗

Absorption, distribution and excretion of SCE-963, a new broad-spectrum cephalosporin, in mice, rats, rabbits and dogs.

A single dose of 20 mg/kg of SCE-963 [7beta-]2-(aminothiazol-4-yl)acetamido]-3-[[[1-(2-dimethylaminoethyl)-1H-tetrazol-5-yl]thio]methyl]ceph-3-em-4-carboxylic acid] was administered subcutaneously to mice, intramuscularly to rats, rabbits and dogs. Plasma and tissue levels of SCE-963 reached a peak in 15 approximately 30 minutes after administration. In mice, rats and dogs, SCE-963 was distributed at high concentration in the descending order in the kidney, liver, plasma, lung and spleen, and in rabbits, in the kidney, plasma, lung, liver and spleen. The SCE-963 levels in the liver of mice, rats and dogs were higher than those of cefazolin, cephaloridine and cephalothin. The plasma and tissue levels of SCE-963 in mice and rats diminished rapidly, but those in rabbits and dogs declined gradually. SCE-963 was mainly excreted in the urine. The rate of excretion of SCE-963 in the bile was two to three times higher than that of cefazolin.

Animals↗

Absorption, distribution and excretion of cefsulodin, an antipseudomonal cephalosporin, in mice, rats and dogs.

A single dose of 20 mg/kg of cefsulodin [3-(4-carbamoyl-1-pyridiniomethyl)-7 beta-(D-alpha-sulfophenylacetamido)-ceph-3-em-4-carboxylate monosodium salt] was administered subcutaneously to mice, and intramuscularly to rats and dogs. The plasma and tissue levels reached the peak 15 approximately 30 minutes after administration. In mice and rats, no plasma levels were measurable 2 and 4 hours after administration. In dogs, the plasma levels were measurable 6 hours after administration. The level in the kidney of mice was slightly lower than the plasma level, while in rats and dogs, the level in the kidney was higher than the plasma level. The cefsulodin levels in the lung of rats and dogs were relatively high, and the level in mice was relatively low. The hepatic levels were very low in all test animal species. Cefsulodin was mainly excreted into the urine, and the excretion of cefsulodin into the bile was very slight.

Animals↗