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At least 19 recordsLinked to original sources
PubMed1978

Bioassay of tetrachlorvinphos for possible carcinogenicity.

A bioassay of technical-grade tetrachlorvinphos for possible carcinogenicity was conducted by administering the test chemical in feed to Osborne-Mendel rats and B6C3F1 mice. Groups of 50 rats of each sex were administered tetrachlorvinphos at one of two doses for 80 weeks, then observed for 31 additional weeks. Time-weighted average doses were either 4,250 or 8,500 ppm. Matched controls consisted of groups of 10 untreated rats of each sex; pooled controls, used for statistical evaluation, consisted of the matched controls combined with 45 untreated male and 45 untreated female rats from similar bioassays of four other test chemicals. All surviving rats were killed at 111 weeks. Groups of 50 mice of each sex were administered tetrachlorvinphos at one of two doses, either 8,000 or 16,000 ppm, for 80 weeks, then observed for 12 additional weeks. Matched controls consisted of groups of 10 untreated mice of each sex; pooled controls, used for statistical evaluation, consisted of the matched controls combined with 40 untreated male and 40 untreated female mice from similar bioassays of four other test chemicals. All surviving mice were killed at 90-92 weeks. The mean body weights of the treated rats and mice were generally lower than those of the matched controls; however, the mortality rate was affected adversely by tetrachlorvinphos only in the male rats. Survival of all groups of rats and mice was adequate for meaningful statistical analyses of the incidence of tumors, except for a matched-control group of female rats for which the survival was abnormally low. In rats, C-cell adenoma of the thyroid showed a significant dose-related trend in the females, using pooled controls (controls 1/46, low-dose 2/50, high-dose 7/46, P=0.013), and by direct comparison, an increased incidence in the high-dose group (P=0.027). High incidences of C-cell hyperplasia in treated males and females further indicated a chemical-related effect on proliferative lesions of the thyroid. Cortical adenoma of the adrenal also showed a significant dose-related trend in the females, using pooled controls (controls 0/50, low-dose 2/49, high-dose 5/50,P=0.017), and by direct comparison, an increased incidence in the high-dose group (P=0.022). Hemangioma of the spleen occurred in male rats at a significantly higher incidence in the low-dose group than in the pooled controls (controls 0/52, low-dose 4/48, P=0.049); however, neither the incidence in the high-dose group (0/47) nor the test result for dose-related trend was statistically significant. In mice, hepatocellular carcinoma in males showed a highly significant dose-related trend, using either matched controls (controls 0/9, low-dose 36/50, high-dose 40/50, P<0.001) or pooled controls (controls 5/49, P<0.001). This finding was supported by direct comparisons of low- and high-dose groups of males with matched- or pooled-control groups, which showed highly significant increases in incidences of the tumor in the treated groups in all instances (P<0.001). In females, the incidence of hepatocellular carcinoma was not significant; however, the incidence of neoplastic nodule was significantly higher in both the low- and high-dose groups than in the pooled controls (controls 1/48, low-dose 14/49, P<0.001; high-dose 9/47, P=0.007), using pooled controls for tests for both doses. Because of this higher incidence in the low-dose group than in the high-dose group, there was a significant departure from linear trend (P=0.006). Granulomatous lesions of the liver were found in high proportions in both treated rats and treated mice, but none were found in matched controls. It is concluded that under the conditions of this bioassay, the administration of technical-grade tetrachlorvinphos in Osborne-Mendel rats was associated with proliferative lesions of the C cells of the thyroid and cortical adenomas of the adrenal in females. In female B6C3F1 mice, the incidence of neoplastic nodule of the liver was associated with treatment, and in male mice tetrachlorvinphos was carcinogenic, causing hepatocellular carcinoma of the liver.

Journal Article↗
PubMed1982

Microbial mutation studies with tetrachlorvinphos (Gardona)).

The mutagenic activity of tetrachlorvinphos was investigated in agar-layer cultures of Escherichia coli WP2 and WP2 uvrA, Salmonella typhimurium TA1535, TA1538, TA98 and TA100. Assays were carried out both in the presence and in the absence of S9 fractions of liver homogenates from rats and mice, both from untreated animals, and from animals pre-treated with Aroclor 1254. The induction of mitotic gene conversion by tetrachlorvinphos was studied in stationary phase cultures of the yeast Saccharomyces cerevisiae D4. No mutagenic effects, as determined by reverse gene mutation, were detected in vitro in the bacterial/mammalian microsome assay when a range of bacterial tester strains were exposed to tetrachlorvinphos at amounts up to 2000 micrograms per plate, either in the absence or in the presence of S9 fractions from non-induced or Aroclor-induced mouse or rat livers. Tetrachlorvinphos did not increase the mitotic gene conversion frequency in stationary phase cultures of the yeast, Saccharomyces cerevisiae D4.

Animals↗
PubMed1983

Cytological effects of the insecticide tetrachlorvinphos.

The effect of the organophosphorus insecticide tetrachlorvinphos (Gardona) has been studied on the mitosis and meiosis of Vicia faba, using the pure insecticide. An aqueous saturated solution of tetrachlorvinphos affected neither mitosis (after seed-soak and root treatment) nor meiosis (after spraying the plants at the flowering stage). The obtained results may be attributed to the low solubility of tetrachlorvinphos. A saturated solution of tetrachlorvinphos in Tween-60: water mixture (1:99) induced a statistically significant percentage of abnormal cells in root-tip meristems after root treatment for 4 h. Chromosome stickiness, disturbed meta- and anaphases and anaphase bridges were observed.

Meiosis↗
PubMed1978

Tetrachlorvinphos as an ineffective feed additive in control of gastrointestinal nematodes of beef cattle.

Tetrachlorvinphos was evaluated for anthelmintic efficacy as a feed additive against gastrointestinal nematodes of cattle. Tetrachlorvinphos was added to the mineral mixture of medicated cattle (n = 13) at the rate of 1.6 mg/day/kg of body weight for a 29-week period beginning May 2, 1975. Data suggest that the level of parasitism, as estimated by the number of nematode eggs per gram of feces, was not reduced by the addition of tetrachlorvinphos to the mineral mixture of medicated cattle. Results obtained from identification and quantification of nematodes recovered at necropsy from 6 medicated and 6 nonmedicated control heifers indicated that tetrachlorvinphos was ineffective as an anthelmintic against gastrointestinal nematodes of cattle.

Animal Feed↗
PubMed1984

Alkylation of urinary guanine in mice by the organophosphorus insecticide tetrachlorvinphos.

The methylating capability of tetrachlorvinphos on urinary guanine in mice has been investigated using an insecticide labeled at both O-CH3 groups. Following intraperitoneal administration of the 14C-labeled insecticide to mice, about 0.57% of the radioactivity in the O- to 24-hr samples was associated with the purine fraction. The amount of [7-14C]methylguanine in 0- to 48-hr urine samples, estimated as fraction of applied dose, was 26-31 X 10(-5). The results obtained indicate possible chemical alkylation of urinary guanine. On the other hand, a considerable portion of radioactivity is probably incorporated via the C-1 pool.

Alkylation↗
PubMed1985

Oncogenic evaluation of tetrachlorvinphos in the B6C3F1 mouse.

Groups of 80 male and 80 female B6C3F1 mice were fed diets containing 17.5, 64, 320, 1600, 8000, and 16000 ppm tetrachlorvinphos (TCVP) for up to 103 weeks. Another group of 80 male and 80 female mice were fed TCVP (16000 ppm) that was used in a previous bioassay. One hundred-sixty male and 160 female mice served as the control group. Ten treated and 20 control mice/sex/group were killed at 6, 12, and 18 months. It was estimated that the study maximum-tolerated dose was exceeded by three- and sixfold in the 8000- and 16000-ppm dose groups, respectively. Consequently, these exposures produced excessive cytotoxicity and regenerative changes in the liver and kidneys which were associated with sex-hormonal imbalance and metabolic overload in liver. A significant decrease (15-40%) in body weight was observed in mice fed 8000 and 16000 ppm TCVP. These treated mice did not gain weight during the study. Reduced food consumption and caloric intake throughout the study were probably responsible for the increased survival and the decreased incidence of spontaneous neoplasia in mice fed 8000 and 16000 ppm TCVP. Classification of pathologic lesions observed in these high-dose groups differed among study and consulting pathologists. The consultant and Shell pathologists concluded that the liver and kidney changes were causally related to excessive toxicity which was manifest primarily by hepatocellular hyperplasia and renal tubular adenoma. Study pathologist in accordance with his classification found statistically significant increases in hepatocellular carcinoma, hepatocellular adenoma or carcinoma, and renal tubular carcinoma in male mice fed 16000 ppm TCVP. The incidence of hepatic neoplasms as evaluated by the study pathologist in female mice fed 8000 and 16000 ppm TCVP although statistically significant was of questionable biologic significance when compared with historical female controls. The only statistically significant finding observed by the consulting pathologist was an increased incidence of renal tubular adenoma and renal tubular adenoma or carcinoma in male mice fed 16000 ppm TCVP. Use of results from these high-dose groups is contraindicated due to the many compromising factors affecting mice fed 8000 and 16000 ppm TCVP. TCVP was found not to be oncogenic in B6C3F1 mice at dose levels not exceeding the maximum tolerated dose.

Animals↗
PubMedDate not supplied

Abnormal in vitro development of ovarian follicles explanted from mice exposed to tetrachlorvinphos.

A system of mouse ovarian follicle culture in which follicles can be grown from a preantral stage of development through antral formation has been developed and modified recently by Nayudu and colleagues. Follicles have been shown to grow in this culture system at a relatively constant rate and show responsiveness to LH at the end of the culture by ovulation of mature oocytes. Reported here are the distinctly different in vitro growth patterns of follicles explanted from 22- to 24-day-old mice during a period when the colony was being treated for skin parasites with tetrachlorvinphos (TCVP) (Rabond). There is to date no information on the effects of this compound on the mammalian female reproductive system. For follicles from the TCVP treated group, the duration of growth as intact follicles was markedly reduced in comparison to mice of the same strain and source not treated with TCVP. In the treated group, premature termination of follicular growth was also associated with the spontaneous expulsion of oocytes with immature nuclei and without cumulus cells. For those follicles from treated mice that did remain in culture until the day luteinizing hormone was given, the ovulatory response was poor and the maturation response of the oocytes was low in comparison with the follicles from untreated mice. The effect of the treatment on the follicles was further characterized by obvious differences in the patterns of growth. Follicles in the untreated group grew in a linear pattern at around 25 microns/day; a single phase, fast pattern for the whole culture period.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

In vivo methylation of guanine by the organophosphorus insecticide tetrachlorvinphos.

The in vivo methylating capability of the organophosphorus insecticide tetrachlorvinphos, assayed by the formation of 7-methyl-guanine in mouse liver, was investigated. Following intraperitoneal injection of male mice with different doses of the 14C-insecticide, labelled at the OCH3 groups, the total and specific radioactivity of nucleic acids and protein were determined. The 14C-labelling in the isolated macromolecules reached its maximum 24 hours following administration of the insecticide. Analysis of the acid hydrolysate of DNA and of RNA on Dowex-50 WX-12 revealed the presence of (7-14C) methylguanine. At maximum 14C-labelling, the amount of radioactive 7-MeGu, calculated as fraction of total dose, was around 9 X 10(-5) and 39 X 10(-5) for DNA and RNA, respectively.

Animals↗
PubMed1982

Dual effects of tetrachlorvinphos on procaine toxicity and procainesterase activity in rats.

The effect of tetrachlorvinphos (TCVP) on liver procainesterase (PROCase) and procaine toxicity was studied in rats. TCVP is an organophosphate with an inducible effect on drug metabolizing enzymes. A single oral dose of 500 mg/kg of TCVP caused a remarkable decrease in PROCase (40% of control) 24 hr later and increased the motality after injection of procaine (250 mg/kg, i.p.) from 54% to 87%. Conversely, it was observed that PROCase elevated to 140% of the control and mortality decreased from 54% to 25% on day 3. With repeated administration of TCVP (500 mg/kg/day) for 5 days, the PROCase activity that was inhibited on day 1 was gradually restored to normal levels by 5 days and the mortality altered to 25%. The inducible effect on PROCase was examined using desmethyl-TCVP, a metabolite of TCVP without inhibitory effect on the enzyme; PROCase activity was enhanced to 1.6-fold of the control and procaine concentration in the brain was reduced to 30% of the control, accompanied with no death of rats after procaine injection. Electrophoresis of the solubilized liver microsomal fraction confirmed the inducible effect of TCVP on PROCase; microsomal protein from the TCVP-treated rat was more deeply stained than that from the control, and the PROCase activity of two anodic bands increased in the TCVP-treated microsomes. These results indicate that TCVP has a dual action on PROCase, inducible and inhibitory, and that the direct inhibitory effect of TCVP might mask the increased amount of the enzyme induced by repeated administration of TCVP. The dual effect of TCVP on PROCase would cause the change in procaine toxicity.

Animals↗
PubMed1990

[Twenty-eight-day repeated dose toxicity test for tetrachlorvinphos in Wistar rat].

A 28-day oral toxicity test of tetrachlorvinphos (TCV) was conducted in male and female Slc: Wistar rats by gavage at dose levels of 0, 10, 100 or 1000 mg/kg/day. The male and female rats showed dose-related inhibition of serum cholinesterase activity and erythrocyte acetylcholinesterase activity. At a dose of 1000 mg/kg, body weight gain was decreased in males, and there were 6 deaths in females. Adrenal gland, liver, kidney and thyroid gland weights were increased. The adrenal lesions were characterized by vacuolization and swelling of the cortex cells. The hepatic lesions consisted of vacuolization and necrosis of the hepatocytes. The renal lesions consisted of regeneration and necrosis of the tubular epithelial cells. These lesions were mostly observed at a dose of 1000 mg/kg. After a 14-day recovery period in the 1000 mg/kg group, the changes of cholinesterase, total cholesterol, gamma-glutamyltransferase, alkaline phosphatase, aspartate aminotransferase and blood urea nitrogen in serum were restored or showed a tendency toward recovery. However, the lesions in the kidney and adrenal remained. More than 14 days are therefore considered to be needed for recovery. At doses of more than 10 mg/kg, significant inhibition of the serum cholinesterase activity in both sexes, erythrocyte acetylcholinesterase activity in males, and lesions of the adrenal gland in females were observed. Target organs for TCV-treated rats were the adrenal, liver and kidney. It was concluded that the NOEL under this experimental condition is less than 10 mg/kg/day.

Administration, Oral↗
PubMed1979

Histopathology of neoplastic and nonneoplastic hepatic lesions in mice fed diets containing tetrachlorvinphos.

Tetrachlorvinphos was fed at 8,000 or 16,000 ppm in diets to male and female (C57BL/6N X C3H/HeN)F1 mice for 80 weeks. Surviving mice were killed at 92 weeks, and all mice were completely necropsied. A high incidence of unusual nonneoplastic hepatic lesions in treated mice was present and characterized by pericellular fibrosis, hepatocyte nuclear pleomorphism, and intrasinusoidal foci of macrophages with intracytoplasmic crystalline structures. From 84 to 94% of the treated male mice and from 21 to 23% of the treated females had hepatocellular neoplasms. Only 17% of the control males and 7% of the control females had liver tumors. The induced tumors were frequently multiple in the liver, whereas the tumors in the controls were usually singular. The morphology of 241 liver tumors in 110 treated mice was different from that of tumors in controls. Liver tumors in control mice were generally composed of small basophillic hepatocytes. In treated mice, tumors were hepatocellular carcinomas composed of solid sheets of large basophilic or eosinophilic hepatocytes. Foci of prominent trabecular formation were seen in 51 tumors. Fifteen tumors were composed of small basophilic hepatocytes with oval cells interposed among them. Foci of capillary formation were noted in 3 of these tumors. In addition, 7 more typical hemangiosarcomas forming sinusoids and with thrombosis were observed.

Animals↗
PubMed1993

Toxicity of tetrachlorvinphos to Rana temporaria L.

1. Changes in the erythrocyte system of frogs poisoned with tetrachlorwinfos depend on the sex of the animals and the dose of pesticide applied. They are a result of the pathomorphological changes due to translocation of fluids from the tissues to the circulation and swelling of the blood cells. 2. Changes in the leucocyte system of frogs are caused by several mechanisms: lytic action of the pesticide on the blood cell membrane, the stressogenic effect of the agent and enhanced activity of the reticuloendothelial system. 3. The appearance of typical changes due to stress, after even the lowest dose of tetrachlorwinfos, and low LD50 values indicate that this pesticide is highly toxic for frogs. 4. The relatively high susceptibility of frogs to intoxication with tetrachlorwinfos is probably the result of a high affinity of cholinesterase to this pesticide, because of the presence of the P = O bond in its molecule.

Animals↗