A Diagnostic Radar Chart method was devised for use in the general assessment of the toxicity of drugs on the basis of visual patterns in toxicity studies. Its usefulness was evaluated on the findings of 32 laboratory ritems in 3 groups of animal models with experimental pathological conditions. The chart was found to facilitate intuitive discrimination among three types of pathological animal models, evaluation of sexual differences and evaluation of individual differences among the animals for each item. Therefore, if patterns are constructed on the Diagnostic Radar Chart for each of the drugs usable for preparing animal models with typical experimental pathological conditions, the chart is thought to be useful for evaluation or identification of the toxicity of an unknown drug.
The potency of food chemicals to induce cell aging was evaluated in human diploid fibroblast cells HAIN-55 having a finite replicative potential by using in vitro aging markers, i.e., decreases of maximum proliferative potential (lifespan) of cells, saturation density in monolayer culture (SD), plating efficiency (PE) and mitotic index (MI), and an increase of cells with polyploid karyotypes. By treatment twice with low concentration of genotoxic chemicals aflatoxin B1, allylisothiocyanate or trans-cinnamaldehyde (severe clastogenic flavoring agent; Kasamaki et al., 1982), lifespan (expressed by the number of cumulative cell population doubling (CPD)) of the treated cells was reduced by 8-12 CPDs accompanied by change of the other aging markers. By successive treatment (29 or 25 times) with non-genotoxic chemical aspartame (N-L-aspartyl-L-phenylalanine) or L-canavanine (structural analogue of L-arginine), lifespan of the treated cells was also slightly shortened (by 2-6 CPDs) compared with the untreated control cells. In the process of cell aging, Mitochondrial activity (MTT activity) decreased almost in parallel with the decrease of SD and MI. On the basis of these results, a variety of genotoxic and non-genotoxic chemicals were examined by using MTT activity as the aging marker for their effects on the aging of HAIN-55 cells and bovine artery endotherial cells which also had a finite replicative potential. The results showed that seven genotoxic and nine non-genotoxic chemicals promoted cell aging.
The effects of rhG-CSF on T-2-induced leukopenia and lethal toxicity in mice were investigated. First, T-2 was administered by gavage to adult male mice at a dose of 3 mg/kg b. w. daily for 7 days, and rhG-CSF was given i. p. in daily dose of 10 or 30 μg/kg b. w./day, beginning on the 2nd day, for 5 days. The peripheral WBC of mice receiving T-2 alone was decreased to one fourth of control counts, and bone marrow (BM) cell counts were also markedly diminished. The administration of rhG-CSF prevented those T-2-induced depressions. Histologically, the delation of the hematopoietic cells from BM and spleen of mice given T-2 was remarkably counteracted by administration of rhG-CSF. In the other experiment, rhG-CSF was injected i. p. for 5 days beginning on the next day of the 7-day T-2 administration. The recovery of WBC and BM cell counts was hastened by rhG-CSF reaching the control level in 6 days, and differential leukocyte analysis revealed an increase of neutrophils. Furthermore, simultaneous administration of rhG-CSF depressed the T-2-induced lethal toxicity, dose-dependently. The results revealed that rhG-CSF possesses a potent ability to protect T-2-induced leukopenia and lethality in mice, and it could be used as an antidote against T-2 and related trichothecene-induced acute intoxication.
Pulmonary fibrosis induction by paraquat was studied histometrically using an image analyzer. Rats were given a subcutaneous injection of paraquat (7 or 25 mg/kg) and autopsied 3, 6 or 9 days later. The percentage of the area of connective fibers per unit area, and lung prolyl hydroxylase activity, as a biochemical parameter, were measured. Rats treated with 25 mg/kg of paraquat showed an increase in the percentage of the area of the connective fibers per unit area and also an increase in lung prolyl hydroxylase activity 6 days later. Thus, pulmonary fibrosis was confirmed both morphologically and biochemically. It is concluded that histometric examination using an image analyzer provides a very accurate method for the evaluation of pulmonary fibrosis.
The teratogenic potential of cis-1-[4-(p-monthane-8-yloxy) phenyl] piperidine (YM9429) was evaluated using CD (SD) rats. YM9429 induced cleft palate and specific skeletal variations including accessory cervical and lumbar ribs or excessive formation of the 7th lumbar vertebra by oral treatment during the organogenetic periods. No visceral or external malformations were induced, and no embryo/fetal mortality or fetal growth retardation was observed. Maternal plasma biochemical examination revealed decreases of cholesterol and phospholipid levels during days 15-17 of pregnancy after the treatment. The results suggest that YM9429 is a potent and specific teratogen inducing cleft palate in CD rats, and the reduced maternal plasma levels of cholesterol and phospholipid during the period of palatine closure are related to the induction of cleft palate.
We studied the ability of 2-PAM to reactivate cholinesterase (ChE) inhibited by organophosphorus compounds (OPs) and aging. We estimated the reactivation rate with 2-PAM following inhibition of ChE by fenitrothion, methylparathion or ethylparathion using erythrocytes of rat and rabbit and rat brain. The period of time during which inhibited ChE could be reactivated was shorter in the case of inhibition by fenitrothion or methylparathion than in the case of inhibition by ethylparathion. This results suggest that aging is related to the presence of the alkyl group in OPs, and occurs faster in the case of inhibition by OPs with an O, O-dimethyl moiety than in the case of inhibition by OPs with an O, O-diethyl moiety.
To investigate the preventive effects of diphenyl dimethyl dicarboxylate (PMC) on the immunotoxicity of carbon tetrachloride (CCl4) in ICR mice, PMC (3 and 6 mg/kg, respectively) were orally administered to mice through a zonde once a day for 28 consecutive days. CCl4 solution was also administered at 1 ml/kg (25%) p.o. 2 hr later the administration of PMC twice a week. Mice were immunized and challenged with sheep red blood cells (SRBC). Immune function were evaluated by humoral, cell-mediated and non-specific immune responses. The results of this study were summarized as follows; 1. The body weight gains and the relative spleen and thymus weights were significantly increased by PMC treatment as compared with treatment of CCl4 alone. However, the relative liver weights were significantly decreased. These values were similar to those of control mice. 2. Hemagglutination (HA) titers were significantly enhanced by PMC treatment as compared with treatment of CCl4 alone. Plaque forming cells (PFC) were also greatly increased by PMC treatment, especially at a dose of 6 mg/kg of it. 3. Delayed-type hypersensitivity (DTH) response was significantly decreased in mice treated with CCl4 and PMC along with the increase of PMC doses, as compared with those in the mice treated with CCl4 alone, while rosette forming cells (RFC) were significantly increased. These results were similar to those of control mice. 4. In PMC treatment as compared with treatment of CCl4 alone, there were significant increases in activities of natural killer (NK) cells and phagocytes along with circulating leukocytes. These results suggest that PMC has significant preventive effect on CCl4-induced immunotoxic status.
The acute toxicity of cadmium (Cd) in male rats was examined with or without Cd pretreatment. Firstly, the metallothionein (MT) contents in the liver and kidney after Cd exposure (2.0 mg/kg, i.v.) were determined. The MT contents in the liver increased immediately to a peak (36.0±5.5 n mol/g wet tissue) 2 days after Cd exposure and were 55-fold higher than that at 0 day (0.64±0.25 n mol/g wet tissue). On the other hand, the MT contents in the kidney increased slightly but steadily for 14 days after Cd exposure. In the study for comparison of Cd-induced toxicity, the LD50 value of the Cd-pretreatment group (Group II) was approximately 2-fold higher than that of the non-pretreatment group (Group I). In microscopic findings, differences between rats in Group I and Group II were recognized in the kidney. Cytoplasmic vacuolation of the proximal tubular epithelium in the kidney was observed in Group I, while degeneration or coagulative necrosis in the proximal tubular epithelium was observed in some rats in Group II in addition to the cytoplasmic vacuolation. Because the toxic changes other than in the kidney in Group II were almost equal to or less than that in Group I, in spite of the doubled dosage of Cd, the toxic effects of Cd, except on the kidneys, were considered to be reduced by the pretreatment with Cd.
The effects of rokitamycin, a macrolide antibiotic, on the binding of bilirubin to albumin were examined in vitro using blood plasma from young rats with hyperbilirubinemia, bilirubin-supplemented serum separated from human cord blood, and the human serum from a newborn infant with icterus gravis neonatorum. Rokitamycin at concentrations from 1 to 500μg/ml (the entire range over which experiments could be conducted) had little or no effect on the concentration of unbound bilirubin in any of the incubation mixtures used. This result suggests that rokitamycin has no effect on the binding of bilirubin to albumin.
The monkey CYP1A1 has been expressed in BALB 3T3 A31-1-1 cells and the expressed proteins were assayed for their capacity to activate aflatoxin B1(AFB1) and benzo[a]pyrene (B[a]P). The transformed cells were approximately 5.4-and 4/7-fold more sensitive to AFB1 and B[a]P than the parental cells, respectively. These results indicate that monkey CYPlA1 cDNA encoded a functional protein and that the expressed CYPlAl enzyme is active for the activation of B[a]P as well as AFB1 to produce toxic metabolites.