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Biomedical subjects

A Takai

Publications and source records attributed to A Takai.

At least 91 records · Page 5Linked to original sources

[Subacute toxicity test of cefoperazone in beagle dogs with the intramuscular administration for 3 months (author's transl)].

The subacute toxicity test of cefoperazone (CPZ), a new cephalosporin antibiotic, was carried out in both sexes of Beagle dogs. CPZ was injected in Beagle dogs intramuscularly at dose levels of 500, 250 and 125 mg/kg/day for 3 months. The same amount of physiological saline was injected to control dogs intramuscularly for 3 months. The following results were obtained: 1) Sign of severe pain was shown immediately after injection in groups of CPZ at 500 and 250 mg/kg/day. In the same groups, the focal necrosis, hemorrhage, cell infiltration and fibrosis of muscles of injected site were noted microscopically. 2) In only one out of 6 dogs given CPZ at 500 mg/kg/day for 3 months, decrease of red blood cells and in values of hemoglobin and hematocrit an increase of reticulocytes in the peripheral blood were observed. In the same dog, splenomegaly and extramedullary hematopoiesis in the liver was found histopathologically, and in addition, the body weight and the food intake decreased during the administration period, associated with the development of anemia. 3) In dogs receiving up to 250 mg/kg/day, atrophy of the thymus was recognized at autopsy and slight decrease of cortical lymphocytes was seen histopathologically. 4) Based on these results, the maximum safety dose of CPZ was thought to be 125 mg/kg/day from the present experiment.

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[The autoradiographic studies on the distribution of 14C-labelled sodium 7-[D(-)-alpha-(4-ethyl-2, 3-dioxo-1-piperazinecarboxamido)-alpha-(4-hydroxyphenyl)-acetamido]-3-[(1-methyl -1 H-tetrazol-5-yl) thiomethyl]-3-cephem-4-carboxylate (14C-cefoperazone) in rats and mice].

The distribution of cefoperazone (CPZ), a new semisynthetic cephalosporin antibiotic, was studied by macroautoradiography following a single intravenous or subcutaneous administration of 100 mg/kg 14C-CPZ to rats, mice, pregnant mice and experimental pyelonephritic mice. (1) In whole body autoradiograms of rats administered subcutaneously and mice administered subcutaneously and intravenously, their distribution patterns of the radioactivity were found to be similar to each case. The radioactivity was distributed at high concentration in liver, kidney, lung, tongue, salivary gland, skin, gastrointestinal tracts and retina. The radioactivity was rapidly excreted in urine and bile. And it was observed that the radioactivity excreted through bile was not reabsorbed from gastrointestinal tracts. (2) In pregnant mice administered intravenously, the radioactivity was observed the same level as whole blood level in placenta, while was hardly observed in fetuses. (3) In the experimental pyelonephritic mice administered intravenously, a considerable radioactivity was concentrated on the acute inflammatory area.

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[General pharmacology of cefoperazone, a new cephalosporin antibiotic (author's transl)].

General pharmacological properties of cefoperazone (CPZ) were studied in various experimental animals. CPZ showed the following effects with intravenous injection to experimental animals. On the central nervous system, CPZ caused vomiting in dogs at 500 mg/kg, pyrexia and slow waves in electroencephalogram in rabbits at 1,000 mg/kg. On the motor and sensory nervous systems, CPZ enhanced slightly the twitch tension of musculus gastrocnemius induced by electrical stimulation in rats at 500 mg/kg. On the respiratory, cardiovascular and autonomic nervous systems, CPZ increased transiently the respiratory rate and potentiated the depressor response to Ach at 125 mg/kg, increased femoral blood flow, potentiated the pressor response to Adr in dogs and decreased the contraction of nictitating membrane induced by electrical stimulation in cats at 500 mg/kg, and then raised the systolic blood pressure in rabbits at 1,000 mg/kg. On the blood, CPZ decreased ChE activity in rabbit plasma at 250 mg/kg, prolonged bleeding time in mice at 500 mg/kg and prothrombin time in rabbits at 1,000 mg/kg. On the smooth muscle organs, CPZ enhanced slightly gastric motility in rabbits and ileal motility in guinea pigs at 62.5 and 125 mg/kg respectively, and promoted gastrointestinal propulsion of BaSO4 meal in mice at 1,000 mg/kg. On the urinary organ, CPZ increased urine volume and electrolytes excretion in dogs at 500 mg/kg. Subcutaneous injection of CPZ scarcely showed any significant effect in experimental animals under the dose of 2,000 mg/kg. In the in vitro experiments, CPZ enhanced slightly the motility of isolated rabbit gastrointestinal tract at 10(-3) g/ml. Assuming the single clinical dose of CPZ should be 10 approximately 40 mg/kg, it is concluded that the occurrence of pharmacological effects observed in experimental animals seems to be very rare clinically.

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