The prevalence of Toxoplasma gondii antibodies in wild and captive cetaceans from Japan.

The seroprevalence of Toxoplasma gondii was investigated in wild and captive cetaceans from Japan. Antibodies against T. gondii were examined by both latex agglutination test (LAT) and indirect hemagglutination test (IHAT) for 77 serum or plasma samples obtained from 59 individuals of 6 species, including 2 hybrids. Antibody titers greater than 1:64 in LAT and greater than 1:640 in IHAT, indicative of the presence of T. gondii, were found in 11.9% of 59 individuals. In 7 samples that showed a positive reaction by IHAT, T. gondii titers were examined for each immunoglobulin (Ig) fraction separated by sucrose gradient centrifugation. The antibody peaks in each fraction were divided into 3 types, thought to be a reaction of IgM (type 1), IgG (type 2), and IgM with IgG (type 3). Type 1 was found in serum from a bottle-nosed dolphin (Tursiops truncatus) and a killer whale (Orcinus orca) sampled soon after capture off the Japanese coast in 1988; it was concluded that infection in the wild had occurred less than 15 yr before the study was performed. The prevalence of putative IgM and IgG antibodies from a captive-bred T. truncatus suggested that T. gondii infection also occurred in the aquarium.

Enhanced utilization of phosphonate and phosphite by Klebsiella aerogenes.

Klebsiella aerogenes ATCC 9621 was able to utilize phosphonates (Pn), including aminoethylphosphonate, ethylphosphonate, methylphosphonate (MPn), and phosphonoacetate, and inorganic phosphite (Pt) as sole sources of phosphorus (P). The products of the phn gene cluster were absolutely required for Pn breakdown and Pt oxidation to inorganic phosphate (Pi) in this organism. To determine if K. aerogenes ATCC 9621 could be engineered to enhance the utilization of Pn and Pt, a multicopy plasmid, pBI05, which carried the entire phn gene cluster, was introduced into this strain. Despite the increased dosage of the phn genes, K. aerogenes ATCC 9621(pBI05) could utilize only up to 1.1-fold more Pn and Pt than did the control strain with the parent vector alone. These results suggested that Pi, which was generated from Pn and Pt, might limit further utilization of these P compounds. Consequently, to convert the resulting Pi to polyphosphate (polyP), the plasmid pKP28, which carried the K. aerogenes ppk gene (which encodes polyP kinase), was introduced into K. aerogenes ATCC 9621(pBI05). Overexpression of the ppk gene in K. aerogenes ATCC 9621(pBI05, pKP28) resulted in a 2.5-fold increase in Pt utilization over that of the control strain. This recombinant strain also accumulated approximately sixfold more P than did the control strain when the cells were grown with MPn as a sole source of P.

Alterations of hepatic drug metabolising system due to dimethylformamide (DMF).

The effect of repeated exposures to N, N-dimethylformamide (DMF) on the liver and the hepatic microsomal monooxygenase system and glutathione metabolizing enzymes were investigated. DMF was administered to Wistar male rats by subcutaneous (s.c.) injection at 1.0 ml/kg body weight (950 mg/kg), 3 times a week for 2 weeks. The gain in the body weight in the DMF group were suppressed compared with the control group at 2 week. The relative weight of the liver, spleen and kidney also appeared to increase in the DMF group as same as in the control group. Hematological examinations showed no changes. Glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) did not change in the DMF group. Hepatic microsomal protein and cytochrome P-450 did significantly decrease by 30% and 38%, respectively, while there was no change in cytochrome b5, NADPH-cytochrome c reductase and NADH-ferricyanide reductase. Glutathione peroxidase (GPx) activity was not affected by DMF administration, while glutathione reductase (GR) and glutathione S-transferase, (GST) activity were significantly increased by 16% and 64%, respectively. These results indicate that DMF alters tke hepatic drug metabolizing system without significant increase of the serum transaminase levels. These findings may contribute to elucidate the mechanism of DMF hepatotoxicity.

Liver injury induced by dichloropropanols--changes in the time course on hematological and blood chemical examinations.

The toxicity of dichloropropanols (DCPs) was investigated by hematological and blood chemical examination. Solutions of two isomers of DCPs, 1,3-dichloro-2-propanol (DC2P) and 2,3-dichloro-1-propanol (DC1P) were dissolved in saline at a concentration of 100 mg/ml and 0.1 ml of each was subcutaneously injected into male Wistar rats weighing about 200 g. Acute changes on transaminases and number of platelets were determined in the time course. 6 hours later, transaminases showed significant increases while the number of platelets significantly decreased in the DC2P-treated group. In the half the of DC2P-treated group, transaminases had increased furthermore at 24 hours, while those in the rest were recovered to the control level. No changes were observed in the DC1P-treated group. These results indicate that there is a prominent hepatotoxicity in DC2P, with the individual diversities to some extent and the hepatic toxicity differs considerably between DC2P and DC1P. Therefore, the monitoring of the working environment and biological monitoring of DCPs should be mandatory, in the workplace where DCPs, especially DC2P, are utilized.

Liver injury and alterations of hepatic microsomal monooxygenase system due to dimethylformamide (DMF) in rats.

The effects of repeated exposure to N, N-dimethylformamide (DMF) on the liver and the hepatic microsomal monooxygenase system were investigated. DMF was administered to Wistar male rats by subcutaneous (s.c.) injection at 0.5 ml/kg body weight daily for 1-17 days. Macroscopically, mild liver swelling was observed and liver weights significantly increased after 3 days of exposure to DMF respectively. Hematological changes were not observed. In exposed rats, glutamic oxaloacetic transaminase and glutamic pyruvic transaminase significantly increased after 3 and 7 days of exposure to DMF. After 17 days of exposure to DMF, transaminases decreased compared to the 7 days. Hepatic microsomal cytochrome P-450 tended to decrease after 3 days of exposure DMF and decreased by 34% after 7 days and 25% after 17 days. Aminopyrine N-demethylase activity depressed significantly while aniline hydroxylase activity showed no change after 3 days of exposure to DMF. These results indicate that DMF alters the hepatic microsomal monooxygenase system. These findings may greatly contribute to the elucidation of the pathogenesis of DMF hepatotoxicity.

Submassive hepatic necrosis induced by dichloropropanol.

A hitherto undescribed industrial liver injury of fulminant form induced by dichloropropanol is reported. Two middle-aged men developed severe hepatic injury just after cleaning a dichloropropanol tank at a plant producing dichloropropanol. They died from hepatic failure 4 and 11 days respectively, after carrying out the work. Liver specimens taken at autopsy from one of the cases showed submassive hepatic necrosis. This accident prompted us to undertake an experimental study in rats of intraperitoneal one-shot injection of two isomeric substances of dichloropropanol, that is, 2,3-dichloro-1-propanol (DC1P) and 1,3-dichloro-2-propanol (DC2P). Saline was injected into the control rats. One, two, four, six, 24, 48, 72 h, and 1 week after the injection, rats in each group were sacrificed. Neither control nor DC1P-injected rats showed significant biochemical or histopathological abnormalities. DC2P-injected rats revealed elevations of transaminase from 6 h after the injections, and submassive necrosis of the liver was observed in many rats. It was concluded that the severe liver injuries in both the human cases and rats in our study were caused by DC2P.

Identification and quantitative analysis of urinary metabolites of dichloropropanols in rats.

Urinary metabolites of dichloropropanols in rats were analyzed by gas chromatography-mass spectrometry (GC/MS). Solutions of dichloropropanols consisting of 1, 3-dichloro-2-propanol (DC2P) and 2, 3-dichloro-1-propanol (DC1P) were diluted in a saline at the concentration of 100 mg/ml, and 0.1 ml of the solutions were subcutaneously injected into male Wistar rats weighing about 160g. The urine samples were collected over a period of 24 hours after the injections. DC2P and DC1P in the urine were extracted with ethylacetate and analyzed by a GC/MS. The derivatization procedure with 4-bromophenylboric acid after acetonitril extraction was applied for the analyses of diols in the urine. By the GC/MS analysis, 3-chloro-1, 2-propanediol (3CPD), 2-chloro-1, 3-propanediol (2CPD) and 1, 2-propanediol (PPD) were identified as the hydroxylated metabolites of dichlorpropanols. Based on the analytical results, the metabolic pathways of dichlorpropanols forming 3CPD and 2CPD, and then hydroxylating to PPD were elucidated.

[Effects of ethylene oxide inhalation on mice].

Male ddY mice were exposed to ethylene oxide (EO) at a concentration of 400 ppm, 6 hours a day, 3 days a week for 13 weeks and the effects of EO on the hepatic drug metabolizing enzymes were investigated. The liver and spleen weight per body weight did not change. Compared to the control group, the kidney weight of the exposed group increased while the testis weight decreased significantly. Hematological examination showed macrocytic anemia in the exposed group. Contents of microsomal cytochrome P-450 in the exposed group increased twice as much as that in the control group, while microsomal protein, cytochrome b5, protoheme and NADPH-cytochrome C reductase activity did not change. NADH-ferricyanide reductase activity of the exposed group increased significantly. Among the glutathione related enzymes in the liver, glutathione reductase and glutathione peroxidase activities in the exposed group decreased but glutathione-S-transferase activity increased significantly.

[Toxicity of dichloropropanols--changes in hematological findings and serum chemistry].

We investigated the toxicity of dichloropropanols (DCPs) in hematological findings and serum chemistry. The solutions of two isomers of DCPs, 1,3-dichloro-2-propanol (DC2P) and 2,3-dichloro-1-propanol (DC1P) were dissolved in saline at the concentration of 100 mg/ml, and 0.1 ml of each solution was subcutaneously injected into male Wistar rats weighing about 200 g. At 6 hours after the injections, in the DC2P group, the number of white blood cells and platelets showed a significant decrease. Transaminases, alkaline phosphatase and lactate dehydrogenase were greatly elevated. Blood urea nitrogen and creatinine also showed a significant increase. There were no changes in the measurements in the DC1P group. These results indicate that there is a prominent hepatotoxicity in DC2P, and that there is a considerable difference in the toxicity present in DC2P and DC1P. Furthermore, in the workplace where DCPs, especially DC2P, is used, the monitoring of the working environment and biological monitoring should be mandatory.

Effects of dimethylformamide on hepatic microsomal monooxygenase system and glutathione metabolism in rats.

The effects of repeated exposure to N,N-dimethylformamide (DMF) on hepatic microsomal monooxygenase system and glutathione metabolism were investigated. DMF was administered to Wistar male rats by subcutaneous (s.c.) injection at 0.5 ml/kg body weight daily for 1 week. Macroscopically, mild liver swelling was observed and liver weights significantly increased after 1 week of exposure to DMF. Hematological changes were not detected. In exposed rats, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, cholinesterase and total cholesterol significantly increased. Hepatic microsomal cytochrome P-450 and protoheme decreased by 34% and 24%, respectively, while microsomal protein and cytochrome b5 were not affected. NADH-ferricyanide reductase activity decreased by 24% while NADPH-cytochrome c reductase activity showed no change. Glutathione reductase (GR) activity showed a significant decrease after the first injection and remained depressed throughout the study, with no change in glutathione peroxidase (GPx) activity. Glutathione S-transferase (GST) activity showed a significant increase at 3 days after DMF treatment and gradually increased by 66% at 1 week. In a subsequent experiment with a single administration of DMF (4 ml/kg), reduced glutathione (GSH) in the liver was decreased by 28% at 8 h, but recovered to control levels by 24 h. These results indicate that DMF alters the hepatic microsomal monooxygenase system and glutathione metabolism. These findings may greatly contribute to the elucidation of the pathogenesis of DMF hepatotoxicity.

[Effects of ethylene glycol on drug metabolizing enzymes in rat liver].

We investigated the effects of ethylene glycol (EG) on the hepatic drug metabolizing enzymes. The exposed group was given 1% EG solution and the control group was provided with distilled water for 2 weeks ad libitum. The body weight of the exposed group was the same as that of the control group. The liver and kidney weight per body weight did not change. The daily drinking volume for the exposed group on the average showed an increase of 13.5% over that of the control group. Hematologically and biochemically, anemia, liver and renal dysfunction were not seen. The content of the hepatic microsomal cytochrome P-450 in the exposed group showed an increase of 17% over that of the control group, but the contents of cytochrome b5, protoheme and the activities of NADPH-cytochrome c reductase, NADH-ferricyanide reductase did not change. The activities of the hepatic cytosolic alcohol dehydrogenase and glutathione reductase, glutathione peroxidase, glutathione-S-transferase also did not change. These results indicate that the hepatic microsomal cytochrome P-450 takes part in the metabolism of EG.

[Effects of ethylene glycol on hepatic microsomal cytochrome P-450].

The effect of ethylene glycol on rat hepatic microsomal cytochrome P-450 was studied in vitro and in vivo. The destruction of cytochrome P-450 was not seen in vitro. The addition of 1 mM NADPH also did not change. When ethylene glycol was added to drinking water at a concentration of 1.0% for 7 days, there was no change in the contents of microsomal protein, cytochrome P-450, b5 and heme. While NADPH-cytochrome C reductase activity of the exposed group did not change, NADH-ferricyanide reductase activity increased significantly.

[Effects of sexual difference on the toxicity of ethylene oxide. III. The rat hepatic monooxygenase system].

Wistar male and female rats were exposed to ethylene oxide (EO) at a concentration of 250 ppm, 6 hours a day, 5 days a week for 17 weeks and the effect of EO on the hepatic monooxygenase system in regards to the sex difference was investigated. Serum GOT of the exposed male rat slightly increased, but that of the female did not change. Contents of microsomal protein and cytochrome P-450 of the male exposed group decreased significantly compared to the male control group, but that of the female exposed group did not change. The change of cytochrome b5, protoheme and NADH-ferricyanide reductase activity of the female exposed group was the same as that of the male. Although NADPH-cytochrome c reductase activity of the male exposed group did not change, that of the female group exposed increased significantly when compared to the female control group. From these observations, we concluded that the effect of EO on the hepatic monooxygenase system was different between male and female.

[Delayed Sumithion intoxication].

A case of delayed Sumithion (fenitrothion) intoxication is reported. A 52-year-old man ingested 10 ml of Sumithion in order to commit suicide with alcohol and triazoram. Several hours later, he was admitted to our hospital because of clouding consciousness. On admission, he was somnolent, but had no other symptoms, especially suggested organophosphorus intoxication. After 40 hours, fasciculation and salivation, which are early symptoms of organophosphorus intoxication, gradually appeared. The concentration of Sumithion in the blood was measured during the course and its metabolism was represented phalmacokineticaly by a 2-compartment model. The retarded metabolism of the Sumithion was suggested by this model. It is considered that the retarded metabolism of Sumithion caused the delayed intoxication.