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The activities of lysosomal maltase in the serum, bile and liver were determined in intrahepatic cholestasis rats induced by alpha-naphtylisothiocyanate (ANIT, 200 mg/kg, i.p.), and compared with changes in alkaline phosphatase (ALP) activity. Moreover, the influences of endogenous bile acids on the release of maltase activity from the liver in intrahepatic cholestasis rats were studied. The maltase activities in the serum and bile significantly increased from 4 and 8 h after the intraperitoneal administration of ANIT, respectively. Conversely, a significant decrease in liver maltase activity was observed from 4 h after the injection of ANIT. On the other hand, total bile acid concentrations in the serum and bile significantly increased immediately after the treatment of ANIT, when biliary bile acid, exogenous bile acid or Triton X-100 was added to lysosomal fraction in the liver, the maltase activity in the supernate after the reaction significantly increased in proportion to the concentration of each substance added to the liver lysosome. These results suggested that maltase might be released from liver lysosomal membrane by surface active-action of bile acid accumulated in the liver after the administration of ANIT. Moreover, the changes in ALP activities in the serum, bile and liver after the administration of ANIT were almost similar to those in maltase activity.

Effects of endotoxin on the motility, the permeability of mesenteric blood vessel and endogenous substances (electrolyte (Na, K), histamine, serotonin and primary prostaglandin) in the small intestine of mice were investigated. Diarrhea was induced by intraperitoneal injection of Salmonella typhosa endotoxin in mice. It is suggested that the diarrheal action of endotoxin is due to the acceleration of intestinal motility and/or the facilitation of mesenteric blood vessel permeability. On the other hand, from the observation of blood concentration of acetaminophen and sulfisoxazole, inhibition of drug absorption was suggested in cases of diarrhea induced by endotoxin. This inhibition of gastrointestinal absorption is due to the delay of the gastric emptying rate, the increase of intestinal transit time of drug in the absorption site and the acceleration of mesenteric blood vessel permeability. Then it is conceivable that these actions may be mediated by biogenic amines (serotonin and histamine) and primary prostaglandins.

The effects of single and multidose 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP) treatment on mice (NMRI and C-57bl) and rats of different ages have been investigated by using the reduction of striatal dopamine uptake rate as a measure of the neurotoxic effect. The possibility that differences in MAO-B activity or in dopamine (DA) uptake rate might explain differences in MPTP toxicity between species, strains or animals of different age was investigated. Single dose MPTP treatment (45 mg/kg) had no effect on 10 day and 3 week old mice, while there was a significant reduction of DA uptake rate at the age of 12 and 40 weeks (both strains). No neurotoxicity of single dose MPTP treatment was observed in the rats, irrespective of their age. Multidose treatment with MPTP (3 x 20-45 mg/kg) caused a reduction of DA uptake rates both in the mice and in the rats at all dose regimens used. The effect of MPTP increased with increasing doses and was most pronounced in the C-57bl mice. Both DA uptake rate and monoamine oxidase B (MAO-B) activity increased with age. The increase in MAO-B activity was highest between 10 days and 3 weeks both in the mice and in the rats. Rats had higher (MAO-B) activity than the mice, while the two species had about the same DA uptake rates. No obvious correlations were found either between MAO-B activities or DA uptake rates and the neurotoxic effect of MPTP.

A highly sensitive and selective glass capillary gas chromatographic negative ion chemical ionization mass spectrometric assay was developed to measure peptidoaminobenzophenone(2-o-chlorobenzoyl-4-chloro-N-methyl-N'-glycylglycinanilide) and its metabolites; chlorodiazepam, chlorodesmethyldiazepam and lorazepam in human plasma. As peptidoaminobenzophenone underwent pyrolysis during gas chromatography, it was converted to a thermally stable aminoquinolone. Internal standards for these compounds were the respective deuterium labelled compounds. Calibration curves were prepared for the range of 1-100 ng ml-1. Interference by endogenous substances was negligible in the isobutane negative ion chemical ionization mode in contrast to the electron impact or positive ion chemical ionization mode. This method was used to determine the plasma levels in humans following oral administration of two 5 mg doses.

Fibrinolytic activity and plasmin inhibitor activity were determined by Blue Dextran-fibrin method in patients with acute myocardial infarction. The normal values of fibrinolytic activity and plasmin inhibitor activity were 3.34 +/- 0.74 units and 10.10 +/- 2.39 units (mean +/- SD), respectively. The fibrinolytic activity in normal women (3.63 +/- 0.99 units) was slightly higher than that in normal men (3.17 +/- 0.79 units), but the plasmin inhibitor was not significantly different in the two sexes statistically. Neither activity varied significantly with age. The blood fibrinolytic activity was depressed in the first week after acute myocardial infarction, the decrease being maximal 3 to 4 days after the event (1.73 +/- 0.31 units). The mean plasmin inhibitor activity remained normal after acute myocardial infarction, but it was increased in 3, and decreased in 4 of 7 patients in whom it was measured 3 to 4 days after the event.

The effects of concanavalin A (Con A) on plasma and brain concentration of aspirin (Asp) were investigated in rats. When Asp was administered in rats treated with Con A, the plasma and brain concentration of Asp and its metabolites (salicylic acid (SA), salicyluric acid (SU) and gentisic acid (GA)) were increased. Distribution of Asp and its metabolites into the hippocampus, striatum and hypothalamus were increased by treatment with Con A. Asp esterase activities in the small intestinal mucosa, liver and brain were increased by pretreatment with Con A, but these enzyme activities were decreased by a high dose of Con A. The inhibitory effect of Asp, SA, SU and GA on the writhing induced by acetic acid in Con A-pretreated mice was stronger than that in the control. A lowering of rectal temperature, after the administration of Asp, was stronger in Con A-treated rats than in control rats. These results suggested that Con A facilitated the absorption of Asp and enhanced the transfer of SA into the brain, and increased Asp esterase activities in various tissues.

The fibrinolytic activity of plasmin was determined by incubating with fibrin-fixed Blue Dextran as a substrate, the Blue Dextran released being proportional to the plasmin activity. The applicability of this method for rapid and accurate evaluation of fibrinolytic activity was demonstrated by dose-response curves with purified plasmin, plasmin generated by urokinase in human plasma and euglobulin. The method can also be used to determined plasmin inhibitors in plasma.

High-performance liquid chromatography was used to determine cyclosporin A (CsA) concentrations in the serum of kidney transplant patients by rapid-flow fractionation (RFF) followed by silica gel normal-phase high-performance liquid chromatography (HPLC). The extraction of CsA from serum was achieved by RFF using a short diatomaceous earth column eluted with diethyl ether-n-hexane (50:50, v/v). The recovery was more than 80% at concentrations of 50-150 micrograms/l. The concentration of this compound was determined by HPLC using a conventional silica gel column with 3.3 M ammonia solution-ethanol-n-hexane (0.31:10.69:89, v/v) as eluent. Concentration calibration was made on the basis of the peak-height ratio of CsA to CsD as the internal standard. The coefficient of variation of this assay was less than 6.5% and the results were used for the therapeutic drug monitoring of CsA administered to kidney transplant patients. Measurements of the CsA concentrations in 160 serum specimens were also made by conventional radioimmunoassay (RIA) using commercial kits. The data obtained by RIA were on average 2.5 times those obtained by HPLC. Higher values in RIA were observed characteristically with patients with severe disfunction resulting from CsA hepatotoxicity. From the results, it appeared that HPLC rather than RIA provides more precise and reliable values for the concentration of this drug.

Effects of various cathartics on charcoal transport, permeability of blood vessels and biogenic amines (serotonin (5-HT), histamine (His), polyamines) in the small intestine of mice were investigated. Diarrhea was induced in mice by oral administration of magnesium sulfate, mannitol, dioctyl sodium sulfosuccinate (DSS), castor oil and pilocarpine. In diarrhea following ingestion of magnesium sulfate and mannitol, vascular permeability in the intestinal membrane accompanied release of His from the small intestine, but such was not so when diarrhea was induced by DSS and castor oil. In diarrhea induced by various cathartics, 5-HT and His were apparently not related to intestinal motility. Thus, alteration in polyamine metabolism in the small intestine may exert an influence on transport of substances in cases of diarrhea in mice.

The activities of lysosomal maltase in the serum, urine and kidney were determined in rats with diabetes induced by streptozotocin (STZ, 75 mg/kg, i.p.) and compared with the changes in N-acetyl-beta-D-glucosaminidase (NAG) activity. Moreover, effects of insulin on maltase and NAG activities of the serum, urine and kidney in diabetic rats were studied. The following results were obtained: 1) The serum maltase activity within 24 hr after administration of STZ was influenced by insulin secretion. 2) Significant increases in blood urea nitrogen (BUN) levels were observed from the 3rd week after a single administration of STZ. The serum insulin level significantly decreased at 3 weeks after treatment of STZ. In this time, maltase activity in the serum rapidly increased, while the enzyme activity in the kidney decreased considerably. On the other hand, the changes in NAG activities in the serum, urine and kidney after administering STZ were almost similar to those in maltase activities. 3) There were positive relationships between maltase and NAG activities in the serum and urine in diabetic rats, respectively. 4) When lente insulin (2U) was subcutaneously injected once daily for 20 days from 24 hr after administration of STZ, NAG activities in the serum and kidney approached to the control levels. However, maltase activities in the group treated with insulin were significantly higher in the serum and kidney than those in the control group.