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Biomedical subjects

K Chiba

Publications and source records attributed to K Chiba.

At least 433 records · Page 24Linked to original sources
PubMed1982

Antipyrine disposition in relation to lowered anticonvulsant plasma level during pregnancy.

The authors studied antipyrine disposition before and after delivery in 4 epileptic women whose anticonvulsant plasma level per dosage ratio was lowered during pregnancy, and compared the results to those found in nonpregnant women undergoing antiepileptic treatment (N = 6) and healthy women (N = 6). The antipyrine clearance at term (0.53 +/- 0.11 ml/min/kg, mean +/- SD) was lower than it was early during puerperium (0.70 +/- 0.14 ml/min/kg, P less than .05) and approximately 3 months after delivery (1.14 +/- 0.26 ml/min/kg, P less than .01). The antipyrine clearance in nonpregnant epileptics (1.17 +/- 0.44 ml/min/kg) was comparable to that found 3 months after delivery, whereas it was significantly (P less than .01) higher than that found in healthy women (0.47 +/- 0.02 ml/min/kg). These observations suggest that the fall during pregnancy of anticonvulsant plasma concentrations relative to dosage is not attributable to the enhanced oxidative process of hepatic drug metabolism.

Adult↗
PubMed1982

Phenytoin--allopurinol interaction: Michaelis--Menten kinetic parameters of phenytoin with and without allopurinol in a child with Lesch--Nyhan syndrome.

We analyzed Michaelis--Menten pharmacokinetic parameters of phenytoin with and without the coadministration of allopurinol (150 and 200 mg/day) in a child with Lesch--Nyhan syndrome. The Vmax and Km were estimated from at least two different sets of serum concentration--dosage data of phenytoin. The Vmax values (mg/kg/day) were 16.1 without allopurinol, and 12.4 and 10.9 with allopurinol (150 and 200 mg/day), respectively, whereas those for Km remained relatively constant (3.9 to 4.9 microgram/ml). Our results suggest that allopurinol is a drug that inhibits the hepatic metabolism of phenytoin.

Adolescent↗
PubMed1981

A comparison between the computed tomogram and the neuropathological findings in cerebrovascular disease.

The findings on computed tomography (CT) and neuropathological examinations were correlated in 87 autopsied cases of cerebrovascular disease with regard to the seize and location of lesions, experience of reviewers, and improvement in CT quality. Small infarctions less than 5 mm were very difficult to detect accurately on CT. This was largely because of the limitations in the efficiency of the CT scanner. Accurate diagnosis of medium sized infarctions was also often difficult. This was mainly due to the anatomical location of lesions, the confluence of deep and widened sulci, periventricular white matter, and structures in the posterior fossa. Large infections could be visualized easily on CT, except in their early periods or in cases with hemorrhagic infarctions. The improved accuracy of CT diagnosis for small and medium sized infarctions could not be attained by the experience of reviewers, but was only possible by instrumental improvement of CT quality.

Cerebral Hemorrhage↗
PubMed1981

Effect of copper administration on the incorporation of [3H]-thymidine into the liver DNA of rats stimulated by dimethylnitrosamine and diethylnitrosamine.

The incorporation of [3H]thymidine into liver DNA of rats increased 6--8 times 48 h after a single injection of dimethylnitrosamine (DMN, 30 mg/kg) and diethylnitrosamine (DEN, 100 mg/kg). To test the suppressive effect of copper, the incorporation of [3H]thymidine into liver DNA in the DMN groups or DEN groups pretreated with copper was measured 48 h after the administration of DMN or DEN. The incorporation of [3H]thymidine into liver DNA of rats stimulated by the injection of DMN was strikingly suppressed by the injection of cupric acetate (20 mg Cu/kg), but that of rats stimulated by the injection of DEN was not suppressed by the injection of copper. Some other metal salts, silver nitrate (20 mg Ag/kg), nickel acetate (20 mg Ni/kg) and basic lead acetate (20 mg Pb/kg) did not significantly suppress the incorporation of [3H]thymidine stimulated by DMN or DEN. The accumulation of copper was much higher in the liver of copper-administered rats than that of nickel or lead in the liver of nickel-administered rats or lead-administered rats. The accumulation of silver was comparatively high in the liver of silver-administered rats.

Animals↗
PubMed1981

Metabolic detoxication of bis-(2-hydroxy-3, 5-dichlorophenyl)-sulfoxide in man.

The metabolic detoxication of bis(2-hydroxy-3, 5-dichlorophenyl)sulfoxide (BTS) in man was investigated. Bis(2-hydroxy-3, 5-dichlorophenyl)sulfide (BT) was identified in beta-glucuronidase treated urine following the administration of BTS by thin-layer chromatography, gas chromatography, ultraviolet spectrum and quantitative analysis. No other metabolites were detectable. BT-glucuronide was also identified in urine. It was assumed that BTS was reduced to BT and successively conjugated with glucuronide in man, and excreted as BT-glucuronide in the urine.

Antiplatyhelmintic Agents↗
PubMed1981

Placental transfer of anticonvulsants (phenobarbital, phenytoin, valproic acid) and the elimination from neonates.

In six full-term newborn infants born to epileptic mothers, the cord-to-maternal concentration ratios of anticonvulsants and the plasma disappearance of the drugs transferred across the placenta were studied. The respective mean +/- SEM values for the ratio of the cord-to-maternal blood concentration were: 0.95 +/- 0.05 (n = 5) for phenobarbital (PB), 0.97 +/- 0.04 (n = 3) for phenytoin (PHT), and 1.71 +/- 0.23 (n = 4) for valproic acid (VPA). The disappearance from the plasma of neonates showed a discernible two-component (initially slow and then fast) curve for all cases with PB, for one with PHT, and for two with VPA. Half-lives calculated from the terminal elimination phase were: 74.0 +/- 8.8 hours for PB (n = 5) and 26.8 +/- 4.8 hours (n = 4) for VPA. The half-life value of PB observed in this study was found to be shorter than that observed postnatally in the previous reports, while that of VPA was two to three times as long as that reported from children or adults, but shorter than that from a neonate in the literature.

Anticonvulsants↗