Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023380 (lethargy)
 5,697 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Methacrylonitrile is an aliphatic nitrile used extensively in the preparation of homo- and copolymers, elastomers, and plastics and as a chemical intermediate in the preparation of acids, amides, esters, and other nitriles. This aliphatic nitrile is also used as a replacement for acrylonitrile in the manufacture of an acrylonitrile/butadiene/styrene-like polymer. Methacrylonitrile was nominated for toxicity and carcinogenicity testing by the National Cancer Institute due to its high production volume and extensive use, the lack of chronic or carcinogenicity data, and its structural resemblance to the known rat carcinogen acrylonitrile. The current 13-week studies were conducted as part of an overall effort by the NTP to assess the toxicity and carcinogenicity of methacrylonitrile. During the 13-week studies, groups of 20 male and 20 female F344/N rats were administered 0, 7.5, 15, 30, 60, or 120 mg methacrylonitrile/kg body weight in deionized, purified water by gavage. Groups of 20 male and 20 female B6C3F1 mice were administered 0, 0.75, 1.5, 3, 6, or 12 mg/kg methacrylonitrile. Ten male and ten female rats and mice from each group were evaluated on day 32. The results of these studies clearly revealed that male rats are more sensitive than females to methacrylonitrile treatment. In the rat study, 19 males and one female administered 120 mg/kg and two males administered 60 mg/kg died during the first week of the study. Males in the 60 mg/kg group at the 32-day interim evaluation and at 13 weeks and females in the 120 mg/kg group at 13 weeks had significantly lower final mean body weights and body weight gains than did the vehicle controls; the surviving male in the 120 mg/kg group also weighed less than the controls at the 32-day interim evaluation. Clinical findings of toxicity were dose dependent and included lethargy, lacrimation, tremors, convulsions, ataxia, and abnormal breathing. There was hematologic evidence indicating that administration of methacrylonitrile induced minimal, normocytic, normochromic anemia. At the 32-day interim evaluation, a minimal dose-related anemia was evidenced by decreases in hematocrit values, hemoglobin concentrations, and erythrocyte counts in male and female rats. The anemia ameliorated by week 13. Administration of methacrylonitrile resulted in dose-related increases in serum thiocyanate and blood cyanide concentrations of male and female rats. These changes were expected and would be consistent with the in vivo metabolism of methacrylonitrile to cyanide. Blood cyanide concentrations were generally higher in males than in females, which may explain the higher sensitivity of males to the lethal effect of methacrylonitrile. There was also biochemical evidence of increased hepatocellular leakage and/or altered function in dosed male rats, suggesting that the liver may be a target organ for toxic effects of methacrylonitrile. Minimal, but significant, decreases in absolute right kidney and thymus weights (32-day interim evaluation) and increases in liver and stomach weights (week 13) occurred in male rats that received 60 mg/kg compared to the vehicle controls. In female rats, stomach weights of the 60 and 120 mg/kg groups were significantly greater and thymus weights of the 120 mg/kg group were significantly less than those of the controls on day 32 and at week 13; liver weights were also significantly greater in females in the 120 mg/kg group than in the vehicle controls on day 32. Male and female rats administered 60 mg/kg and females administered 120 mg/kg had significantly greater incidences of metaplasia of the nasal olfactory epithelium on day 32 and at the end of the study than did the vehicle controls; incidences of olfactory epithelial necrosis were also significantly greater in females in the 60 and 120 mg/kg groups than in the vehicle controls on day 32. Incidence and/or severity increased with increasing dose in females; however, the mortality in male rats administered 120 mg/kg made it difficult to assess the dose-response relationship in males. The no-observed-adverse-effect level for the nasal cavity of rats was 30 mg/kg. Female rats administered 60 or 120 mg/kg methacrylonitrile had significantly longer estrous cycles than did the vehicle controls. Females in the 60 mg/kg group spent more time in diestrus than the vehicle controls. One male and one female mouse in the 12 mg/kg groups died early. Methacrylonitrile administration caused no significant differences in final mean body weights or body weight gains. Clinical findings included lethargy, tremors, ataxia, convulsions, and abnormal breathing. At the 32-day interim evaluation, stomach weights of males administered 3 mg/kg or greater were significantly greater and thymus weights of males in the 12 mg/kg group were significantly less than those of the vehicle controls. At week 13, however, the stomach weights of only males in the 12 mg/kg group were increased relative to the vehicle controls. No treatment-related histopathologic lesions occurred in mice. Methacrylonitrile did not induce mutations in any of several strains of Salmonella typhimurium, with or without S9 activation, and did not induce sex-linked recessive lethal mutations in germ cells of male Drosophila melanogaster fed methacrylonitrile during the larval stage. Results of in vivo bone marrow micronucleus tests with methacrylonitrile in male rats and mice were also negative. In summary, gavage administration of methacrylonitrile to rats and mice resulted in dose-dependent lethargy, tremors, lacrimation, convulsions, and abnormal breathing. However, these effects were more pronounced in rats than mice; these differences may be attributed to the higher doses of methacrylonitrile administered to rats. Body weight gain and survival data of rats demonstrated that males are more sensitive to methacrylonitrile dosing than females. There is an apparent correlation between blood cyanide concentrations and survival rates, with males having greater cyanide concentrations and lower survival rates than female rats administered methacrylonitrile. Microscopically, the only target of methacrylonitrile toxicity was the olfactory epithelium of the nasal cavity. Necrotic and metaplastic effects were induced in male and female rats that received 60 or 120 mg/kg per day. No similar lesions were observed in mice administered methacrylonitrile. The no-observed-adverse-effect level for olfactory epithelial lesions in male and female rats administered methacrylonitrile for 13 weeks was 30 mg/kg per day. No clear chemical-related effects were observed in male or female mice administered methacrylonitrile for 13 weeks by gavage at doses up to 12 mg/kg per day.
 ...
PMID:NTP technical report on the toxicity studies of methacrylonitrile (CAS No. 126-98-7). Administered by gavage to F344/N rats and B6C3F1 mice. 1180 6

Primidone is used alone or with other anticonvulsants in the control of grand mal, psychomotor, and focal epileptic seizures. It may control grand mal seizures refractory to other anticonvulsant therapy. Primidone was nominated by the National Cancer Institute for 2-year toxicology and carcinogenicity studies due to its human use as an anticonvulsant. Male and female F344/N rats and B6C3F1 mice received primidone (greater than 99% pure) in feed for 14 days, 14 weeks, or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, cultured Chinese hamster ovary cells, and mouse bone marrow cells. 14-DAY STUDY IN RATS: Five male and five female rats were exposed to 0, 1,250, 2,500, 5,000, 10,000 or 20,000 ppm primidone (equivalent to average daily doses of approximately 120, 240, 500, 970, or 1,100 mg primidone/kg body weight to males and 120, 240, 500, or 900 mg/kg to females) in feed for 14 days. All 20,000 ppm females died before the end of the study as did one 10,000 ppm male and two 20,000 ppm males. The mean body weights of 10,000 ppm males and females and 20,000 ppm males were significantly less than those of the controls. Feed consumption by all exposed rats was generally similar to that by the controls. Males and females in the 10,000 and 20,000 ppm groups were observed to have eye discharge, ataxia, and abnormal posture and were thin and lethargic. 14-DAY STUDY IN MICE: Five male and five female mice were exposed to 0, 625, 1,250, 2,500, 5,000 or 10,000 ppm primidone (equivalent to average daily doses of approximately 100, 200, 400, or 800 mg/kg body weight to males and 100, 250, 500, or 900 mg/kg to females) in feed for 14 days. All mice in the 10,000 ppm groups and one male and one female mouse in the 5,000 ppm groups died on day 3 of the study. The mean body weights of mice in the 625, 1,250, 2,500, and 5,000 ppm groups were similar to those of the controls. Feed consumption by all exposed mice was generally similar to that by the controls. Males and females in the 10,000 ppm groups were observed to have abnormal posture, ataxia, and lethargy. 14-WEEK STUDY IN RATS: Groups of 10 male and 10 female rats were exposed to 0, 300, 600, 1,300, 2,500, or 5,000 ppm primidone (equivalent to average daily doses of approximately 20, 40, 100, 200, or 400 mg/kg) in feed for 14 weeks. All rats survived to the end of the study. The mean body weights of male and female rats in the 2,500 and 5,000 ppm groups were significantly less than those of the controls. Feed consumption by all exposed rats was generally similar to that by the controls. A minimal to mild exposure-related thrombocytosis occurred on day 22 and at week 14 in all exposed groups of male rats and in females in the 1,300 ppm or greater groups. A minimal decrease in hemoglobin concentration occurred in 2,500 and 5,000 ppm male and female rats on day 22 and at week 14. The incidences of centrilobular hepatocyte hypertrophy in male rats exposed to 600 ppm or greater and in female rats exposed to 1,300 ppm or greater were significantly greater than those in the controls. The severity of chronic nephropathy in male rats exposed to 1,300 ppm or greater increased with increasing exposure concentration. 14-WEEK STUDY IN MICE: Groups of 10 male and 10 female mice were exposed to 0, 300, 600, 1,300, 2,500, or 5,000 ppm primidone (equivalent to average daily doses of approximately 50, 100, 200, 400, or 1,000 mg/kg to males and 60, 120, 220, 440, or 1,100 mg/kg to females) in feed for 14 weeks. Three male and two female mice in the 5,000 ppm group died during week 1 of the study. The final mean body weights of all exposed groups were similar to those of the controls. Feed consumption by male mice in the 5,000 ppm group was slightly greater than that by the controls; this may have been due to feed spillage. Male and female mice in the 5,000 ppm groups were ataxic and lethargic. Compared to controls, the estrous cycle lengths of females exposed to 1,300, 2,500, or 5,000 ppm were significantly longer. The liver weights of male and female mice exposed to 600 po 600 ppm or greater were significantly greater than those of the controls. The incidences of centrilobular hepatocyte hypertrophy in all exposed males and in females exposed to 600 ppm or greater and the incidences of cytoplasmic alteration of the adrenal gland and hematopoietic cell proliferation of the spleen in 2,500 and 5,000 ppm males and in 5,000 ppm females were significantly greater than in the controls. 2-YEAR STUDY IN RATS: Groups of 50 male and 50 female F344/N rats were exposed to 0, 600, 1,300, or 2,500 ppm primidone (equivalent to average daily doses of approximately 25, 50, or 100 mg/kg) in feed for 2 years. Survival, Body Weights, and Feed Consumption Survival of the 1,300 and 2,500 ppm males was sig nificantly less than that of the controls. The mean body weights of males and females in the 2,500 ppm groups were less than those of the controls, beginning at week 29 for males and week 17 for females; the mean body weights of 1,300 ppm males and females were less than those of the controls during the second year of the study. Feed consumption by all exposed groups of rats was generally similar to that by the controls. Pathology Findings Male rats exposed to primidone had increased inci dences of thyroid gland follicular cell neoplasms (adenoma and/or carcinoma). All exposed groups of male rats had follicular cell adenomas or carcinomas (combined) at incidences above the historical control range, with the highest incidence in the 1,300 ppm group. Hepatocyte cytoplasmic vacuolation and centrilobular hypertrophy were associated with primidone exposure in male and female rats. These changes were more severe in females than in males and the incidences in all exposed groups of females were significantly greater than those in the controls. Females in the 2,500 ppm group had an increased incidence of hepatocellular eosinophilic foci. In 2,500 ppm males, the incidence of renal tubule hyperplasia was greater than that in the controls in the standard evaluation. Additional hyperplasias were found in the extended evaluation, and the incidences in exposed groups of males were significantly greater than that in the controls. In the extended evaluation, the incidence of renal tubule adenoma in 2,500 ppm males was significantly increased. The incidence of adenoma or carcinoma (combined) in 2,500 ppm males in the combined standard and extended evaluations were marginally increased over those in the controls. Male rats had an exposure-related increase in the severity of chronic nephropathy, which probably accounted for the reduced survival in the 1,300 and 2,500 ppm groups. The incidences of kidney cysts were increased in 1,300 and 2,500 ppm males. Hyperparathyroidism, secondary to the loss of renal function, was present in many exposed male rats. The incidences of parathyroid gland hyperplasia in all groups of exposed males were significantly greater than that in the controls. 2-YEAR STUDY IN MICE: Groups of 50 male and 50 female mice were exposed to dietary levels of 0, 300, 600, or 1,300 ppm primidone (equivalent to average daily doses of approximately 30, 65, or 150 mg/kg to males and 25, 50, or 100 mg/kg to females) in feed for 2 years. Survival, Body Weights, Feed Consumption, and Clinical Findings Survival of the 1,300 ppm males was significantly less than that of the controls. During the second year of the study, the mean body weights of 1,300 ppm male and female mice were less than those of the controls. The final mean body weights of 600 ppm males and females were less than those of the controls. Feed consumption by all exposed groups of mice was similar to that by the controls. During the latter part of the study, a treatment-related increase in the number of animals with swelling of the abdominal area was observed; necropsy revealed that the swelling was due to liver nodules/masses. Pathology Findings The liver was a target organ in both male and female mice. The incidences and multiplicities of hepatocellular neoplasms (hepatocellular adenoma, hepatocellular carcinoma, and hepatoblastoma) in all exposed groups of males and females (except hepatoblastoma in females) were significantly greater than those in the controls. The incidences of hepatocellular adenoma or carcinoma (combined) and hepatocellular adenoma, hepatocellular carcinoma, or hepatoblastoma (combined) in all exposed groups exceeded the historical control ranges in 2-year NTP studies. The incidences of centrilobular hepatocyte hypertrophy were increased in exposed groups of males and females, and the severities increased with increasing exposure concentration. The incidences of cytoplasmic vacuolization were increased in all exposed groups of females and in 300 ppm males. Incidences of eosinophilic focus in all exposed groups of females were significantly greater than those in the controls. Proliferative changes occurred in the thyroid gland in an exposure-related manner in male and female mice. Incidences of follicular cell hyperplasia were increased in all exposed groups of males and in 600 and 1,300 ppm females, but incidences of follicular cell adenomas were increased only in male mice. GENETIC TOXICOLOGY: Primidone was mutagenic in Salmonella typhimurium strain TA1535 in the absence of S9 activation only; no mutagenicity was detected in strain TA98, TA100, or TA1537, with or without S9. Primidone did not induce sister chromatid exchanges or chromosomal aberrations in cultured Chinese hamster ovary cells, with or without S9. The single in vivo study with primidone, a mouse bone marrow micronucleus test, also gave negative results. CONCLUSIONS: Under the conditions of these 2-year feed studies, there was equivocal evidence of carcinogenic activity of primidone in male F344/N rats based on a marginal increase in thyroid gland follicular cell neoplasms, primarily adenomas, and a marginal increase in renal tubule neoplasms. There was no evidence of carcinogenic activity of primidone in female F344/N rats exposed to 600, 1,300, or 2,500 ppm. There was clear evidence of carcinogenic activity of primidone in male B6C3F1 mice based on the increased incidences of hepatocellular neoplasms, and the increased incidence of thyroid gland follicular cell adenomas was also considered to be chemical related. There was clear evidence of carcinogenic activity of primidone in female B6C3F1 mice based on the increased incidences of hepatocellular neoplasms. Exposure of rats to primidone resulted in increased incidences of hepatocyte cytoplasmic vacuolization and centrilobular hypertrophy in males and females and eosinophilic foci in females. The increased severity of nephropathy and increased incidence of renal tubule hyperplasia in male rats were related to primidone exposure. Exposure of male mice to primidone resulted in hepatocyte centrilobular hypertrophy and thyroid gland follicular cell hyperplasia. Exposure of female mice to primidone resulted in hepatocyte centrilobular hypertrophy and cytoplasmic vacuolization, eosinophilic focus, and thyroid gland follicular cell hyperplasia. Synonyms: 5-Aethyl-5-phenyl-hexahydropyrimidin-4,6-dion; 2-deoxyphenobarbital; 2-desoxyphenobarbital; desoxyphenobarbitone; 5-ethyldihydro-5-phenyl-4,6 (1H,5H)-pyrimidinedione; 5-ethylhexahydro-4,6-dioxo-5-phenylphrimidine; 5-ethylhexahydro-5-phenylpyrimidine-4,6-dione; 5-ethyl-5-phenylhexahydropyrimidine-4,6-dione Trade names: Cyral; Hexadiona; Hexamidine; Lepimidin; Lepsiral; Majsolin; Midone; Milepsin; Misodine; Misolyne; Mizodin; Mizolin; Mylepsin; Mylepsinum; Mysedon; Mysoline; Prilepsin; Primacione; Primaclone; Primacone; Primakton; Primadon; Prysoline; Pyrimidone; ROE 101; Sertan
 ...
PMID:NTP Toxicology and Carcinogenesis Studies of Primidone (CAS No. 125-33-7) in F344/N Rats and B6C3F1 Mice (Feed Studies). 1257 87

Nickel sulfate hexahydrate is used in nickel plating, as a mordant in dyeing and printing textiles, as a blackening agent for zinc and brass, and in the manufacture of organic nickel salts. Nickel sulfate hexahydrate was nominated by the National Cancer Institute to the NTP as part of a class study of nickel compounds for which there was little information on the toxic and carcinogenic effects of inhalation exposure. Male and female F344/N rats and B6C3F1 mice were exposed to nickel sulfate hexahydrate (greater than 98% pure) by inhalation for 16 days, 13 weeks, or 2 years. Genetic toxicology studies were conducted in L5178Y mouse lymphoma cells. 16-DAY STUDY IN RATS: Groups of five male and five female F344/N rats were exposed to 0, 3.5, 7, 15, 30, or 60 mg nickel sulfate hexahydrate/m(3) (equivalent to 0, 0.7, 1.4, 3.1, 6.1, or 12.2 mg nickel/m(3)). Rats were exposed on weekdays only, for a total of 12 exposure days during a 16-day period. Additional groups of four or five male and female F344/N rats were exposed to 0, 3.5, 15, or 30 mg nickel sulfate hexahydrate/m(3)for tissue burden studies. In the core study, two 60 mg/m(3) males, one 30 mg/m(3) female, and all 60 mg/m(3)females died before the end of the study. Final mean body weights of all exposed groups of males and females were significantly lower than those of the controls, as were mean body weight gains of male rats. Clinical findings included increased rates of respiration and reduced activity levels in rats in all exposure groups, except those exposed to 3.5 mg/m(3). Absolute lung weights of 60 mg/m(3) males and of all exposed groups of females were significantly greater than those of the controls, as were the relative lung weights of all exposed groups of males and females. Inflammation (including degeneration and necrosis of the bronchiolar epithelium) occurred in the lungs of all exposed groups of males and females. Atrophy of the olfactory epithelium occurred in the nasal passages of all exposed groups of males (except 60 mg/m(3)) and in 15, 30, and 60 mg/m(3) females. Lymphoid hyperplasia in the bronchial or mediastinal lymph nodes was observed in 30 mg/m(3) males and in 60 mg/m(3) males and females. The concentration of nickel in the lungs of all exposed groups of males and females was greater than in control animals. 16-DAY STUDY IN MICE: Groups of five male and five female B6C3F1 mice were exposed to 0, 3.5, 7, 15, 30, or 60 mg nickel sulfate hexahydrate/m(3). Mice were exposed on weekdays only, for a total of 12 exposure days during a 16-day period. Additional groups of five male and five female B6C3F1 mice were exposed to 0 or 3.5 mg nickel sulfate hexahydrate/m(3)for tissue burden studies. All core study mice exposed to 7 mg/m(3) or greater died before the end of the study; all control and 3.5 mg/m(3)mice survived to the end of the study. Final mean body weights and weight gains of 7, 15, 30, and 60 mg/m(3)males and females were significantly less than those of the controls, and clinical findings in these groups included emaciation, lethargy, and rapid respiration rates. Absolute and relative lung weights of male and female mice exposed to 7 mg/m(3) or greater were significantly greater than those of the controls. Only tissues from mice exposed to 0, 3.5, or 7 mg/m(3) were examined histopathologically. Inflammation occurred in the lungs of 3.5 and 7 mg/m(3) males and females; necrosis of the alveolar and bronchiolar epithelium was a component of the inflammation in 7 mg/m(3)males and females. In addition, atrophy of the olfactory epithelium of the nasal passages was observed in 3.5 mg/m(3) males and females. Nickel concentrations in the lungs of mice exposed to 3.5 mg/m(3) were greater than those in the controls. 13-WEEK STUDY IN RATS: Groups of ten male and ten female F344/N rats were exposed to 0, 0.12, 0.25, 0.5, 1, or 2 mg nickel sulfate hexahydrate (equivalent to 0, 0.03, 0.06, 0.11, 0.22, or 0.44 mg nickel/m(3)), 5 days per week for 13 weeks. Additional groups of six male and six female F344/N rats were exposed to 0, 0.12, 0.5, or 2 mg nic mg nickel sulfate hexahydrate/m(3)for tissue burden studies. In the core study, one 2 mg/m(3)male rat died before the end of the study; all other males and all females survived until the end of the study. Final mean body weights and body weight gains of all exposed groups were similar to those of the controls. There were no significant clinical findings noted during the study. Exposure-related increases in neutrophil and lymphocyte numbers occurred and were most pronounced in female rats. With the exception of 0.12 mg/m(3)rats, absolute and relative lung weights of all exposed groups were generally significantly greater than those of the controls. Exposure-related increases in the incidence and severity of inflammatory lesions (alveolar macrophages, chronic inflammation, and interstitial infiltration) occurred in the lungs of all exposed groups of males and females. Lymphoid hyperplasia of the bronchial and/or mediastinal lymph nodes occurred in males exposed to 0.5 mg/m(3)or greater. Atrophy of the olfactory epithelium occurred in males and females exposed to 0.5, 1, and 2 mg/m(3)and in 0.25 mg/m(3)females. The concentration of nickel in the lungs of 0.5 and 2 mg/m(3) rats was greater than that in the lungs of control animals at 4, 9, and 13 weeks for males and at 13 weeks for females. 13-WEEK STUDY IN MICE: Groups of ten male and ten female B6C3F1 mice were exposed to 0, 0.12, 0.25, 0.5, 1, or 2 mg nickel sulfate hexahydrate, 5 days per week for 13 weeks. Additional groups of up to five or six male and female B6C3F1 mice were exposed to 0, 0.12, 0.5, or 2 mg nickel sulfate hexahydrate/m(3)for tissue burden studies. In the core study, four control males, three control females, and one 0.12 mg/m(3)male died before the end of the study; the deaths were not considered to be chemical related, and all other mice survived to the end of the study. The final mean body weights and body weight gains of all exposed groups were similar to those of the controls. There were no chemical-related clinical findings. Hematology changes similar to those reported in female rats occurred in female mice, but the mice were minimally affected. The absolute and relative lung weights of 1 mg/m(3)males and 2 mg/m(3)males and females were significantly greater than those of the controls. Increased numbers of alveolar macrophages occurred in all males and females exposed to 0.5 mg/m(3)or greater. Chronic active inflammation and fibrosis occurred in 1 and 2 mg/m(3)males and females. Lymphoid hyperplasia of the bronchial lymph node and atrophy of the olfactory epithelium in the nasal passages were observed in 2 mg/m(3)males and females. Nickel concentration in the lung of 2 mg/m(3)females was significantly greater than in control animals. 2-YEAR STUDY IN RATS: Groups of 63 to 65 male and 63 to 64 female rats were exposed to nickel sulfate hexahydrate by inhalation at concentrations of 0, 0.12, 0.25, or 0.5 mg/m(3) (equivalent to 0, 0.03, 0.06, or 0.11 mg nickel/m(3)). Animals were exposed for 6 hours plus T90 (8 minutes) 5 days per week for 104 weeks. Five male and five female rats from each group were evaluated at 7 months for histopathology; an additional seven males and seven females from each group were evaluated at 7 months for nickel tissue burden in the lung and kidney; and five males and five females from each group were evaluated at 15 months for alterations in hematology, nickel tissue burden in the lung and kidney, and histopathology. Survival, Body Weights, Clinical Findings, and Hematology The survival rates of all exposed groups of males and females were similar to those of the controls. Mean body weights of 0.5 mg/m(3)female rats were slightly lower (6% to 9%) than those of the controls throughout the second year of the study; final mean body weights of all exposed groups of males and 0.12 and 0.25 mg/m(3)females were similar to those of the controls. There were no clinical findings or hematology differences that were considered to be related to nickel sulfate hexahydrate administration. Pathology Findings No exposure-related neoplasms occurred in male or female rats exposed by inhalation to nickel sulfate hexahydrate for 2 years. Increased incidences of inflammatory lung lesions were generally observed in all exposed groups of male and female rats at the end of the study. The incidences of chronic active inflammation, macrophage hyperplasia, alveolar proteinosis, and fibrosis were markedly increased in male and female rats exposed to 0.25 or 0.5 mg/m(3). Increased incidences of lymphoid hyperplasia in the bronchial lymph nodes occurred in 0.5 mg/m(3)male and female rats at the end of the 2-year study. The incidences of atrophy of the olfactory epithelium in 0.5 mg/m(3)males and females were significantly greater than those in controls at the end of the study. Tissue Burden Analyses Lung nickel burdens in exposed male and female rats were greater than those in the controls at the 7- and 15-month interim evaluations, and lung nickel burdens values increased with increasing exposure concentration. 2-YEAR STUDY IN MICE: Groups of 80 male and 80 female mice were exposed to nickel sulfate hexahydrate by inhalation at concentrations of 0, 0.25, 0.5, or 1 mg/m(3) (equivalent to 0, 0.06, 0.11, or 0.22 mg nickel/m(3)). Animals were exposed for 6 hours plus T90 (8 minutes) 5 days per week for 104 weeks. Five male and five female mice from each group were evaluated at 7 months for histopathology; five males and five females from each group were evaluated at 7 months for nickel tissue burden in the lung and kidney; five males and five females from each group were evaluated at 15 months for alterations in hematology and histopathology; and five males and five females from each group were evaluated at 15 months for nickel tissue burden in the lung and kidney. Survival, Body Weights, Clinical Findings, and Hematology The survival rates of all exposed groups of males and females were similar to those of the controls. The mean body weights of 1 mg/m(3)males and of all exposed groups of females were lower than those of the controls during the second year of the study. There were no clinical findings or hematology differences considered to be related to chemical exposure. Pathology Findings Inflammatory lesions of the lung generally occurred in all exposed groups of male and female mice at the end of the 2-year study. These lesions included macrophage hyperplasia, chronic active inflammation, bronchialization (alveolar epithelial hyperplasia), alveolar proteinosis, and infiltrating cells in the interstitium. Incidences of macrophage hyperplasia and/or lymphoid hyperplasia occurred in the bronchial lymph nodes of most of the 1 mg/m(3)males and females and in some 0.5 mg/m(3)females at the end of the 2-year study. Atrophy of the olfactory epithelium was observed in 0.5 and 1 mg/m(3)males and in all exposed groups of females at the end of the 2-year study. Tissue Burden Analyses At the 7- and 15-month interim evaluations, lung nickel burden parameters measured in control and exposed groups were below the limit of detection. Absolute lung weights of 0.5 and 1 mg/m(3)lung burden study females were significantly greater than those of the controls at 15 months. GENETIC TOXICOLOGY: Nickel sulfate hexahydrate (500 to 800 g/mL) was tested for induction of trifluorothymidine resistance in L5178Y mouse lymphoma cells. A positive response was observed in the absence of S9. The test was not performed with S9. CONCLUSIONS: Under the conditions of these 2-year inhalation studies, there was no evidence of carcinogenic activity of nickel sulfate hexahydrate in male or female F344/N rats exposed to 0.12, 0.25, or 0.5 mg/m(3) (0.03, 0.06, or 0.11 mg nickel/m(3)). There was no evidence of carcinogenic activity of nickel sulfate hexahydrate in male or female B6C3F1 mice exposed to 0.25, 0.5, or 1 mg/ m3 (0.06, 0.11, or 0.22 mg nickel/m(3)). Exposure of rats to nickel sulfate hexahydrate by inhalation for 2 years resulted in increased incidences of chronic active inflammation, macrophage hyperplasia, alveolar proteinosis, and fibrosis of the lung; lymphoid hyperplasia of the bronchial lymph node; and atrophy of the olfactory epithelium. Exposure of mice to nickel sulfate hexahydrate by inhalation for 2 years resulted in increased incidences of chronic active inflammation, bronchialization (alveolar epithelial hyperplasia), macrophage hyperplasia, interstitial infiltration, and alveolar proteinosis of the lung; lymphoid and macrophage hyperplasia of the bronchial lymph node; and atrophy of the olfactory epithelium. Synonyms: Blue salt; hexahydrate, nickel (2+) salt; nickel monosulfate hexahydrate; nickel (2+) sulfate hexahydrate; nickel (II) sulfate hexahydrate; nickel sulphate hexahydrate; nickelous sulfate hexahydrate; nickelous sulphate hexahydrate; single nickel salt, sulfuric acid
 ...
PMID:NTP Toxicology and Carcinogenesis Studies of Nickel Sulfate Hexahydrate (CAS No. 10101-97-0) in F344 Rats and B6C3F1 Mice (Inhalation Studies). 1258 12

Isobutyl nitrite is used to a limited extent as an intermediate in the syntheses of aliphatic nitrites. It is also an ingredient of various incenses or room odorizers and is used as a euphoric. The chemical has also been used as a jet propellant and in the preparation of fuels. Isobutyl nitrite was nominated by the Consumer Product Safety Commission to the NTP for toxicology and carcinogenicity studies because of its possible contribution to the high incidence of Kaposi's sarcoma among male homosexual acquired immune deficiency syndrome patients and because of the lack of available data on the potential carcinogenicity of isobutyl nitrite. Male and female F344/N rats and B6C3F1 mice were exposed to isobutyl nitrite (purity of 93% or greater) by inhalation for 16 days, 13 weeks, or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, cultured Chinese hamster ovary cells, Drosophila melanogaster, and mouse peripheral blood. 16-DAY STUDY IN RATS: Groups of five male and five female F344/N rats were exposed to 0, 100, 200, 400, 600, or 800 ppm (approximately 420, 840, 1,700, 2,500, or 3,300 mg/m(3)) isobutyl nitrite by inhalation for 6 hours per day, 5 days per week for a total of 12 exposures during a 16-day period. All males and females exposed to 600 or 800 ppm and one 400 ppm female died on the first day of the study. Final mean body weights and mean body weight gains of 400 ppm males and females were significantly lower than those of the controls. Clinical findings observed in 400 ppm males and females included ocular discharge, lethargy, hunched posture, and rough coats. Absolute and relative lung weights of all exposed groups of males and of 200 and 400 ppm females were less than those of the controls. Chemical-related hyperplasia of the bronchial epithelium was observed in 200 and 400 ppm males and females and hyperplasia of the nasal turbinate epithelium was observed in rats exposed to 400 ppm or less. Hemosiderin pigmentation was observed in the spleen of 200 and 400 ppm males and females and bone marrow hematopoietic hyperplasia was observed in rats exposed to 400 ppm or less. 16-DAY STUDY IN MICE: Groups of five male and five female B6C3F1 mice were exposed to 0, 100, 200, 400, 600, or 800 ppm (approximately 420, 840, 1,700, 2,500, or 3,300 mg/m(3)) isobutyl nitrite by inhalation for 6 hours per day, 5 days per week for a total of 12 exposures during a 16-day period. Three males and four females exposed to 800 ppm died before the end of the study. Final mean body weights and mean body weight gains of 600 and 800 ppm males and females were significantly lower than those of the controls. Mice exposed to 400 ppm or greater were lethargic and exhibited hunched posture and rough coats. Absolute and relative lung weights of 600 and 800 ppm males and the relative lung weight of 600 ppm females were significantly greater than those of the controls. Chemical-related hyperplasia of the bronchiolar epithelium was observed in all exposed groups of males and females. Lymphocytic atrophy of the spleen and thymus was observed in males and females exposed to 400 ppm or greater. 13-WEEK STUDY IN RATS: Groups of 10 male and 10 female F344/N rats were exposed to 0, 10, 25, 75, 150, or 300 ppm (approximately 42, 105, 315, 630, or 1,260 mg/m(3)) isobutyl nitrite by inhalation for 6 hours per day, 5 days per week for 13 weeks. All rats survived to the end of the study. Final mean body weights and mean body weight gains of 300 ppm males and females were significantly lower than those of the controls, as was the mean body weight gain of 150 ppm females. Clinical findings observed during the study included ruffled fur in 300 ppm males and females, hypoactivity in 300 ppm males, and hyperactivity in 150 and 300 ppm females. A very mild chemical-related methemoglobinemia and anemia occurred in male and female rats in the 75, 150, and 300 ppm groups. Hematopoietic hyperplasia occurred in the bone marrow of all exposed groups of males and females and was considered to be a secondary response to the anemia and methed methemoglobinemia. There was minimal hemosiderin pigment accumulation in the spleens of males and females exposed to 75 ppm or greater, mild to moderate epithelial cell hyperplasia of the nasal mucosa was observed in 300 ppm males and females, and minimal hyperplasia occurred in 150 ppm males and females. Hyperplasia of the bronchial epithelium was observed in 300 ppm males and females. 13-WEEK STUDY IN MICE: Groups of 10 male and 10 female B6C3F1 mice were exposed to 0, 10, 25, 75, 150, or 300 ppm (approximately 42, 105, 315, 630, or 1,260 mg/m(3)) isobutyl nitrite by inhalation for 6 hours per day, 5 days per week for 13 weeks. There were no chemical-related deaths. Final mean body weights and mean body weight gains of 150 and 300 ppm females were significantly less than those of the controls. Final mean body weights and mean body weight gains of exposed groups of males were similar to those of the controls. There were no chemical-related clinical findings. A very mild chemical-related methemoglobinemia occurred in male and female mice in the 150 and 300 ppm groups. A very mild anemia occurred in the 300 ppm groups. In the lung, increased incidences of mild to moderate hyperplasia of the bronchiolar epithelium occurred in males and females exposed to 300 ppm. Minimal hyperplasia occurred in males exposed to 75 ppm or greater and in females exposed to 150 ppm. Minimal epithelial cell hyperplasia of the nasal mucosa was observed in 300 ppm males. Increased hematopoiesis of the spleen, secondary to the hematotoxicity, occurred in males exposed to 75 ppm or greater and in females exposed to 150 or 300 ppm. Increased hemosiderosis of the spleen occurred in males exposed to 300 ppm and in females exposed to 75 ppm or greater. 2-YEAR STUDY IN RATS: Based on the low final mean body weights, anemia, and the mild to moderate nasal mucosal lesions and the hyperplastic bronchial lesions observed in 300 ppm males and females, isobutyl nitrite exposure concentrations selected for the 2-year inhalation study in rats were 37.5, 75, and 150 ppm. Groups of 56 male and 56 female rats were exposed to 0, 37.5, 75, or 150 ppm (equivalent to 0, 158, 315, or 630 mg/m(3)) isobutyl nitrite by inhalation for 6 hours per day, 5 days per week, for 103 weeks. Ten male and 10 female rats from each group were evaluated at 15 months for clinical pathology and histopathology. Survival, Body Weights, Clinical Findings, Hematology, and Clinical Chemistry: Survival rates of exposed groups of rats were greater than those of the controls, and the survival rates of 75 and 150 ppm males were significantly greater than that of the control. Mean body weights of 150 ppm males and females were 3% to 11% lower than those of the controls throughout the course of the study. There were no clinical findings considered to be related to isobutyl nitrite exposure. A very mild methemoglobinemia and anemia occurred in male and female rats exposed to 75 or 150 ppm. Pathology Findings: Incidences of alveolar/bronchiolar adenoma and alveolar/bronchiolar adenoma or carcinoma (combined) occurred with significant positive trends in exposed males and females, and the incidences of these neoplasms in 75 ppm males and in 150 ppm males and females were significantly greater than those in the controls. The incidence of alveolar/bronchiolar carcinoma was significantly greater in 150 ppm male rats than that in the controls. The incidences of alveolar epithelial hyperplasia were also increased in 75 and 150 ppm males and in all exposed groups of females. The incidences of mononuclear cell leukemia in exposed groups of males and females were significantly less than those in the controls. 2-YEAR STUDY IN MICE: Based on the low final mean body weight of 300 ppm females and the mild to moderate bronchiolar hyperplasia observed in 300 ppm males and females, isobutyl nitrite exposure concentrations selected for the 2-year inhalation study in mice were 37.5, 75, and 150 ppm. Groups of 60 male and 60 female mice were exposed to 0, 37.5, 75, or 150 ppm (equivalent to 0, 158, 315, or 630 mg/m(3)) isobutyl nitrite by inhalation for 6 hours per day, 5 days per week, for 103 weeks. As many as 10 male and 10 female mice from each group were evaluated at 15 months for clinical pathology and histopathology. Survival, Body Weights, Clinical Findings, and Hematology and Clinical Chemistry: Survival rates of exposed groups of males were similar to those of the controls. Survival rates of exposed groups of females were greater than those of the controls, and the survival rate in 37.5 ppm females was significantly greater than that of the controls. Mean body weights of exposed groups of males and of 37.5 and 75 ppm females were similar to those of the controls throughout the study. Mean body weights of 150 ppm females were lower than those of the controls from week 20 until the end of the study. There were no biologically significant clinical findings noted in the 2-year study in mice. A very mild methemoglobinemia and anemia occurred in male and female mice exposed to 75 or 150 ppm. Pathology Findings: Incidences of alveolar/bronchiolar adenoma and alveolar/bronchiolar adenoma or carcinoma (combined) occurred with significant positive trends in exposed males and females, and the incidences of these neoplasms were significantly greater than those in the controls in 75 ppm males and in 150 ppm males and females. Incidences of alveolar epithelial hyperplasia were significantly increased in 75 and 150 ppm male and female mice. Thyroid gland follicular cell adenoma occurred with a significant positive trend in male mice; the incidences of thyroid gland follicular cell hyperplasia were increased in all exposed groups of males, and the incidences in males exposed to 37.5 or 150 ppm were significantly greater than those in the controls. Incidences of serous exudate and olfactory epithelium atrophy in the nose of 150 ppm females were significantly greater than those in the controls. Incidences of minimal to mild hemosiderin pigment in the spleen of 75 and 150 ppm male mice were significantly greater than those in the controls. GENETIC TOXICOLOGY: Isobutyl nitrite was found to be mutagenic in vitro and in vivo. It induced base-pair substitution mutations in Salmonella typhimurim strains TA100 and TA1535 and sister chromatid exchanges and chromosomal aberrations in cultured Chinese hamster ovary cells. Positive responses in the S. typhimurium tests required S9 activation, but isobutyl nitrite induced chromosomal effects in cultured Chinese hamster ovary cells with and without S9. In vivo, no induction of sex-linked recessive lethal mutations was noted in the germ cells of male Drosophila melanogaster exposed to isobutyl nitrite via feeding or injection. However, significant increases in micronucleated normochromatic erythrocytes were observed in the peripheral blood of male and female mice treated with isobutyl nitrite for 90 days by inhalation. CONCLUSIONS: Under the conditions of these 2-year inhalation studies, there was clear evidence of carcinogenic activity of isobutyl nitrite in male and female F344/N rats based on the increased incidences of alveolar/bronchiolar adenoma and alveolar/bronchiolar adenoma or carcinoma (combined). There was some evidence of carcinogenic activity of isobutyl nitrite in male and female B6C3F1 mice based on the increased incidences of alveolar/bronchiolar adenoma and alveolar/bronchiolar adenoma or carcinoma (combined) in males and females. The increased incidence of thyroid gland follicular cell adenoma in male mice may have been related to isobutyl nitrite exposure. Exposure of rats and mice to isobutyl nitrite by inhalation for 2 years resulted in increased incidences of alveolar epithelial hyperplasia (male and female rats and mice), thyroid gland follicular cell hyperplasia and splenic hemosiderin pigmentation (male mice), and serous exudate and atrophy of the olfactory epithelium of the nose (female mice). Exposure of rats to isobutyl nitrite by inhalation for 2 years resulted in decreased incidences of mononuclear cell leukemia in males and females.
 ...
PMID:NTP Toxicology and Carcinogenesis Studies of Isobutyl Nitrite (CAS No. 542-56-3) in F344 Rats and B6C3F1 Mice (Inhalation Studies). 1259 27

1-Trans-delta(9)-tetrahydrocannabinol (THC) was nominated by the National Cancer Institute to the NTP for study because it is the major psychoactive component of marijuana and a widely used Schedule I substance. Male and female F344/N rats and B6C3F1 mice received THC (97% pure) in corn oil by gavage for 13 weeks, 13 weeks with a 9-week recovery period, or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, cultured Chinese hamster ovary cells, and mouse peripheral blood cells. 13-WEEK STUDY IN RATS: Groups of 10 male and 10 female rats received 0, 5, 15, 50, 150, or 500 mg THC/kg body weight in corn oil by gavage, 5 days per week for 13 weeks. Six male and six female rats receiving 500 mg/kg died before the end of the study. The final mean body weights and weight gains of all dosed groups of males and females, except 5 mg/kg females, were significantly lower than those of the controls. Feed consumption by dosed groups was similar to that by controls. Clinical findings observed during the study included lethargy, sensitivity to touch, convulsions, tremors, and aggressiveness. There were no clinical pathology differences considered to be directly related to the administration of THC. The absolute and relative uterus weights of 50, 150, and 500 mg/kg females were significantly lower than those of the controls. Treatment-related multifocal atrophy was observed in the testes of 150 and 500 mg/kg males; uterine and ovarian hypoplasia observed in 150 and 500 mg/kg females was also considered to be related to THC administration. Based on final mean body weights and mortality observed in the 13-week study, doses selected for the 2-year rat study were 12.5, 25, and 50 mg/kg. 13-WEEK STUDY IN MICE: Groups of 10 male and 10 female mice received 0, 5, 15, 50, 150, or 500 mg THC/kg body weight in corn oil by gavage, 5 days per week for 13 weeks. There were no treatment-related deaths. The final mean body weight and weight gain of 500 mg/kg males were significantly lower than those of the controls. Clinical findings included lethargy and aggressiveness, and both male and female mice in all dosed groups were easily startled. There were no absolute or relative organ weight differences, clinical pathology differences, or microscopic changes observed that were considered to be related to the administration of THC. Due to the minimal THC-related effects observed in the 13-week study, doses selected for the 2-year mouse study were 125, 250, and 500 mg/kg. 13-WEEK WITH 9-WEEK RECOVERY STUDY IN RATS: Groups of 10 male and 10 female rats received 0, 5, 15, 50, 150, or 500 mg THC/kg body weight in corn oil by gavage, 5 days per week for 13 weeks, and then were allowed to recover during a 9-week treatment-free period. Five male and eight female 500 mg/kg rats, five male and two female 150 mg/kg rats, and three male and two female 50 mg/kg rats died before the end of the study. During the 13-week dosing period, mean body weight gains of all dosed groups of rats were lower than those of the controls but returned to normal during the recovery period. Final mean body weights of all dosed groups were similar to those of the controls. Clinical findings observed during the recovery period included sensitivity to touch, convulsions, and aggressiveness. The absolute right testis weight of 500 mg/kg males was significantly lower than that of the controls. Treatment-related multifocal atrophy of the testis was observed in 150 and 500 mg/kg males. There were no treatment-related lesions observed in females administered THC. 13-WEEK WITH 9-WEEK RECOVERY STUDY IN MICE: Groups of 10 male and 10 female mice received 0, 5, 15, 50, 150, or 500 mg THC/kg body weight in corn oil by gavage, 5 days per week for 13 weeks, and then were allowed to recover during a 9-week treatment-free period. The final mean body weights of all dosed groups were similar to those of the controls. Clinical findings observed during the study included lethargy and aggressiveness, and both male and female mice in all dosed groups were easily startled. The absolutebsolute and relative uterus weights of 150 and 500 mg/kg female mice were significantly lower than those of the controls, as was the absolute uterus weight of 50 mg/kg females. 2-YEAR STUDY IN RATS: Groups of 62 vehicle control male rats, 60 low-dose male rats, 70 mid- and high-dose male rats, and 60 female rats were administered 0, 12.5, 25, or 50 mg THC/kg body weight in corn oil by gavage for 104 to 105 weeks. Nine or ten animals from each group were evaluated at 15 months. Survival, Body Weights, and Clinical Findings: Survival of all dosed groups was generally significantly greater than that of the controls. Mean body weights of dosed groups of males and females were lower than those of the controls throughout the study. Convulsions and seizures were observed in all dosed groups of male and female rats, usually following dosing or handling. Hematology and Clinical Chemistry: At the 15-month interim evaluation, total leukocyte and lymphocyte counts in all dosed groups of females were greater than those of the controls, and platelet counts in these groups were lower than that of the controls. Levels of follicle stimulating and luteinizing hormones in all dosed groups of males were significantly greater than those of the controls, as was the serum corticosterone level of 25 mg/kg females. Pathology Findings: No increased incidences of neoplasms were considered related to administration of THC. The incidences of mammary gland fibroadenoma and uterine stromal polyps were decreased in dosed groups of females, as were the incidences of pituitary gland adenomas, interstitial cell adenomas of the testis, and pancreatic adenomas in dosed males. 2-YEAR STUDY IN MICE: Groups of 62 vehicle control male mice, 60 low-dose male mice, 61 mid-dose male mice, and 60 high-dose male mice and 60 female mice were administered 0, 125, 250, or 500 mg THC/kg body weight in corn oil by gavage for 104 to 105 weeks (males) or 105 to 106 weeks (females). Survival, Body Weights, and Clinical Findings: Survival of 500 mg/kg males was significantly less than that of the controls; survival of all other groups of males and of all dosed groups of females was similar to that of the controls. Mean body weights of all dosed groups were markedly lower than those of the controls throughout the study. Clinical findings in dosed groups included hyperactivity, convulsions, and seizures which occurred following dosing or handling. Hematology: At the 15-month interim evaluation, total leukocyte and lymphocyte counts in all dosed groups of males were significantly lower than those of the controls. Pathology Findings: Increased incidences of thyroid gland follicular cell adenoma occurred in 125 mg/kg males and females, but the increase was not dose-related. Increased incidences of thyroid gland follicular cell hyperplasia occurred in all dosed groups of males and females. Increased incidences of forestomach hyperplasia and ulcers occurred in all groups of males administered THC. Incidences of hepatocellular adenoma and of hepatocellular adenoma or carcinoma (combined) occurred with a significant negative trend in male and female mice, as did incidences of eosinophilic foci and fatty change in the liver. GENETIC TOXICOLOGY: THC was not mutagenic in Salmonella typhimurium strains TA97, TA98, TA100, or TA1535 with or without rat and hamster liver S9 fractions. In cultured Chinese hamster ovary cells, THC induced sister chromatid exchanges at the highest dose tested in the presence of S9; at this dose level, cell cycle delay indicative of toxicity was observed. THC did not induce chromosomal aberrations in cultured Chinese hamster ovary cells with or without S9 metabolic activation enzymes. In vivo, no increase in the frequency of micronucleated erythrocytes was observed in the peripheral blood of male or female mice administered THC by gavage for 13 weeks. CONCLUSIONS: Under the conditions of these 2-year gavage studies, there was no evidence of carcinogenic activity of 1-trans-delta(9)-tetrahydrocannabinol in male or female F344/N rats administered 12.5, 25, or 50 mg/kg. There was equivocal evidence of carcinogenic activity of THC in male and female B6C3F1 mice based on the increased incidences of thyroid gland follicular cell adenomas in 125 mg/kg groups. Increased incidences of thyroid gland follicular cell hyperplasia occurred in male and female mice, and increased incidences of hyperplasia and ulcers of the forestomach were observed in male mice. The incidences of mammary gland fibroadenomas and uterine stromal polyps were decreased in dosed groups of female rats, as were the incidences of pancreatic adenomas, pituitary gland adenomas, and interstitial cell adenomas of the testis in dosed male rats and liver neoplasms in dosed mice. These decreases were likely related to lower body weights in dosed animals. Synonyms: 3-Pentyl-6,6,9-trimethyl-6a,7,8,10a-tetrahydro-6h-dibenzo(b,d)pyran-1-ol; delta1-tetrahydrocannabinol; (-)-delta1-3,4-trans- tetrahydrocannabinol; delta(9)-tetrahydrocannabinon; THC; delta1-THC; delta(9)-THC
 ...
PMID:NTP Toxicology and Carcinogenesis Studies of 1-Trans-Delta(9)-Tetrahydrocannabinol (CAS No. 1972-08-3) in F344 Rats and B6C3F1 Mice (Gavage Studies). 1259 29

p-Nitrobenzoic acid is produced in large volumes for organic synthesis and as an intermediate in the manufacture of pesticides, dyes, and industrial solvents. Groups of male and female F344/N rats and B6C3F1 mice were exposed to p-nitrobenzoic acid (>99% pure) in feed for 14 days, 13 weeks, or 2 years for toxicity and carcinogenicity studies. Genetic toxicology studies were conducted in in vitro assays with Salmonella typhimurium and cultured Chinese hamster ovary cells, and in studies of erythrocyte micronucleus formation in mice in the 13-week study. 14-DAY STUDY IN RATS: Groups of five male and five female rats were given 0, 2,500, 5,000, 10,000, 20,000, or 40,000 ppm p-nitrobenzoic acid in feed for 14 days. All rats survived until the end of the study. Male and female rats given 20,000 and 40,000 ppm lost weight. The final mean body weights of 10,000, 20,000, and 40,000 ppm males were 82%, 60%, or 52% that of the controls, and the final mean body weights of 10,000, 20,000, and 40,000 ppm females were 87%, 68%, and 65% that of the controls. There were no clinical findings that were characteristic of organ-specific toxicity. Absolute and relative spleen weights were significantly increased in rats exposed to 10,000, 20,000, and 40,000 ppm. There were decreases in erythrocyte count and hemoglobin and hematocrit values and increases in reticulocyte count, nucleated erythrocytes, and methemoglobin concentration that were most pronounced in the 20,000 and 40,000 ppm groups. Congestion of the spleen occurred in 10,000 ppm males and in 20,000 and 40,000 ppm females. Hypertrophy of the follicular epithelium of the thyroid gland was present in male and female rats exposed to 10,000, 20,000, or 40,000 ppm p-nitrobenzoic acid, while follicular hyperplasia was observed in the 40,000 ppm males and females. Atrophy of the testis was observed in 20,000 and 40,000 ppm males. Other lesions observed in 20,000 and 40,000 ppm rats included atrophy of the thymus in males and atrophy of the ovary, bone marrow, and thymus in females. 14-DAY STUDY IN MICE: Groups of five male and five female mice were given 0, 2,500, 5,000, 10,000, 20,000, or 40,000 ppm p-nitrobenzoic acid in feed for 14 days. Three males and two females given 40,000 ppm died during the study. All other animals survived until the end of the study. Male mice given 20,000 and 40,000 ppm and females given 20,000 ppm lost weight. Mean body weight gains of 20,000 and 40,000 ppm males and 10,000, 20,000, and 40,000 ppm females were significantly lower than those of the controls. There were no clinical findings related to organ-specific toxicity although lethargy and ataxia were observed in 40,000 ppm mice. Relative liver weights were significantly increased in 20,000 and 40,000 ppm males and females and in 10,000 ppm females. Absolute and relative thymus weights of 20,000 and 40,000 ppm males and of 10,000, 20,000, and 40,000 ppm females were reduced. No significant differences in hematology parameters occurred in exposed mice. Testicular degeneration was observed in three 20,000 ppm and two 40,000 ppm males. Bone marrow hemorrhage and atrophy occurred in 40,000 ppm females. 13-WEEK STUDY IN RATS: Groups of 10 male and 10 female rats were given 0, 630, 1,250, 2,500, 5,000, or 10,000 ppm pnitrobenzoic acid in feed for 13 weeks resulting in approximate daily doses of 40, 70, 160, 310, or 660 mg/kg to males and 40, 80, 170, 340, or 680 mg/kg to females. All rats survived until the end of the study. Mean body weight gains and final mean body weights were significantly less than those of the controls in 2,500, 5,000, and 10,000 ppm males and in 5,000 and 10,000 ppm females. There were no clinical findings related to organ-specific toxicity. Differences in spleen weights and hematology parameters characteristic of regenerative anemia were observed in males and females, primarily in groups given 10,000 ppm. The absolute and relative spleen weights were significantly increased in 10,000 ppm males and females and the relative spleen weights were significantly increased in 5,000 ppm males hts were significantly increased in 5,000 ppm males and females. Methemoglobin, Heinz bodies, and reticulocyte counts were increased and erythrocyte counts, hemoglobin, and hematocrit values were decreased in 10,000 ppm males and females. Congestion, pigmentation, and accumulation of macrophages in the spleen and pigmentation in the kidney occurred in 2,500, 5,000, and 10,000 ppm males. Congestion and pigmentation of the spleen occurred in 10,000 ppm females. A yellowish brown pigment (hemosiderin) in the spleen and kidney was associated with hemolytic anemia. Mild cytoplasmic hyaline droplet accumulation was present in renal tubule epithelial cells in 10,000 ppm males while karyomegaly was present in male and female rats exposed to 2,500, 5,000, and 10,000 ppm p-nitrobenzoic acid. A chemical-related testicular lesion, consisting of atrophy of the seminiferous tubules, occurred in 10,000 ppm males. 13-WEEK STUDY IN MICE: Groups of 10 male and 10 female mice were given 0, 1,250, 5,000, 10,000, or 20,000 ppm pnitrobenzoic acid in feed for 13 weeks resulting in approximate daily doses of 170, 330, 670, 1,900, or 4,000 mg/kg body weight to males and 240, 460, 970, 2,500, or 4,900 mg/kg to females. All mice survived until the end of the study, except one 1,250 ppm female that was killed accidentally. Final mean body weights and mean body weight gains of all exposed males and of 5,000, 10,000, and 20,000 ppm females were significantly lower than those of the controls. No clinical findings or differences in organ weights or histopathology related to organ-specific toxicity were observed in exposed mice. 2-YEAR STUDY IN RATS: Groups of 60 male and 60 female rats were given 0, 1,250, 2,500, or 5,000 ppm p-nitrobenzoic acid in feed for 2 years. Ten males and 10 females from each exposure group were evaluated at 15 months. Survival, Body Weights, Feed Consumption, and Clinical Findings: Two-year survival rates of 1,250 and 2,500 ppm males were similar to that of the controls. Two-year survival of 5,000 ppm males was marginally greater than that of the controls and was attributed in part to a decrease in the severity of nephropathy and a decrease in the incidence of mononuclear cell leukemia. Survival of exposed females was similar to that of the controls. Mean body weights of 5,000 ppm males were 2% to 8% lower than those of the controls through week 80. Final mean body weights of exposed males were similar to that of the controls. Mean body weights of 5,000 ppm females were 2% to 9% lower than those of the controls during the first year of the study and were 10% to 16% lower during the second year of the study. Final mean body weights of exposed females were 97% (1,250 ppm), 92% (2;500 ppm), and 84% (5,000 ppm) that of the controls. Feed consumption by exposed males and females was similar to that by the controls. Dietary levels of 1,250, 2,500, or 5,000 ppm p-nitrobenzoic acid delivered approximately 50, 100, or 210 mg/kg body weight per day to males and 60, 125, or 250 mg/kg per day to females. There were no clinical findings attributable to organ-specific toxicity. Pathology Findings: There were increases in the incidences of clitoral gland adenoma and of clitoral gland adenoma or carcinoma (combined) (4/50, 14/49, 15/49, 15/50) in exposed females. The incidences of clitoral gland adenoma or carcinoma (combined) in the exposed groups (29% to 31%) exceeded the historical control mean incidence (11%) and range (2% to 21%) in female F344/N rats in recent 2-year NTP feed studies. The increased incidences of clitoral gland neoplasms were considered to be some evidence of carcinogenic activity in female rats exposed to p-nitrobenzoic acid. The incidences of hyperplasia of the clitoral gland in exposed females were marginally lower than that of the controls (10/50, 6/49, 6/ 49, 7/50). There was a chemical-related decrease in the severity of nephropathy in male rats. Male rat kidneys were examined using both single and step-section analyses, and the incidences of renal tubule neoplasms were not statistically greater than those of the controls. Mild hyaline droplet accumulation was observed in renal tubule epithelial cells in 10,000 ppm males in the 13-week study, but this effect was not severe enough to lead to a chemical-related neoplastic response in the 2-year study as has been observed with other chemicals. At the 15-month interim evaluation, hematologic parameters characteristic of a mild regenerative anemia and significant differences in spleen weights were noted in 5,000 ppm females. These differences included decreases in erythrocyte count, hemoglobin, and hematocrit, increases in spleen weights, and hemosiderin accumulation in splenic macrophages. At 2 years, significant decreases in the incidences of mononuclear cell leukemia were observed in 5,000 ppm males and 2,500 and 5,000 ppm females (males: 29/50, 35/50, 26/50, 2/50; females: 17/50, 11/50, 3/50, 0/50). While the mechanism for this decrease is unknown, decreases in the incidence of mononuclear cell leukemia have also been observed in 2year studies with other amine/nitro compounds. 2-YEAR STUDY IN MICE: Groups of 60 male and 60 female mice were given 0, 1,250, 2,500, or 5,000 ppm p-nitrobenzoic acid in feed for 2 years. Ten males and 10 females from each exposure group were evaluated at 15 months. Survival, Body Weights, Feed Consumption, and Clinical Findings: Two-year survival rates of exposed mice were similar to those of the controls. Mean body weights of 5,000 ppm males were 6% to 12% lower than those of the controls after week 17, and mean body weights of 5,000 ppm females were 12% to 24% lower than those of the controls after week 16. The final mean body weight of 5,000 ppm females was 19% less than that of the controls; final mean body weights of males were similar to that of the controls. Feed consumption by exposed mice was similar to that by the controls. Dietary levels of 1,250, 2,500, or 5,000 ppm p-nitrobenzoic acid delivered approximately 150, 300, or 675 mg/kg per day to males and 170, 365, or 905 mg/kg per day to females. There were no clinical findings of organ-specific toxicity. No chemical-related effects on hematology parameters were noted at the 15-month interim evaluation. Pathology Findings: There were no increases or decreases in neoplasms in male or female mice that were considered to be related to chemical administration. GENETIC TOXICOLOGY: p-Nitrobenzoic acid was mutagenic in Salmonella typhimurium strain TA100 with and without S9. No mutagenic activity was noted in strains TA98, TA1535, or TA1537, with or without S9. p-Nitrobenzoic acid induced sister chromatid exchanges and chromosomal aberrations in cultured Chinese hamster ovary cells in the absence of S9; with S9, results of both tests were negative. In vivo, no increase in micronuclei was observed in peripheral blood erythrocytes of male or female mice administered p-nitrobenzoic acid in dosed feed for 13 weeks. CONCLUSIONS: Under the conditions of these 2-year feed studies, there was no evidence of carcinogenic activity of p-nitrobenzoic acid in male F344/N rats exposed to 1,250, 2,500, or 5,000 ppm. There was some evidence of carcinogenic activity of p-nitrobenzoic acid in female F344/N rats based on increases in the incidences of clitoral gland adenoma and of clitoral gland adenoma or carcinoma (combined). There was no evidence of carcinogenic activity of p-nitrobenzoic acid in male or female B6C3F1 mice exposed to 1,250, 2,500, or 5,000 ppm. There were chemical-related decreases in the incidences of mononuclear cell leukemia in exposed male and female rats. p-Nitrobenzoic acid caused mild hematologic toxicity in female rats. Synonyms: 4-Nitrobenzoic acid; nitrodracylic acid; p-nitrobenzenecarboxylic acid; p-carboxynitrobenzene
 ...
PMID:NTP Toxicology and Carcinogenesis Studies of p-Nitrobenzoic Acid (CAS No. 62-23-7) in F344/N Rats and B6C3F1 Mice (Feed Studies). 1259 21

NTP Toxicology and Carcinogenesis studies of a-methylbenzyl alcohol (greater than 99% pure), a cosmetic ingredient and food flavoring agent, were conducted by administering the chemical in corn oil by gavage to groups of F344/N rats and B6C3F1 mice of each sex for 16 days, 13 weeks, or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, mouse lymphoma cells, and Chinese hamster ovary (CHO) cells. a-Methylbenzyl alcohol was nominated for study by the National Cancer Institute because of the potential for widespread human exposure. Sixteen-Day and Thirteen-Week Studies: The doses used in the 16-day studies for rats and mice ranged between 125 and 2,000 mg/kg. Six of 10 rats and all mice dosed at 2,000 mg/kg died. In addition, because 7/9 mice dosed at 1,000 mg/kg died, the doses selected for the 13-week studies for mice (47-750 mg/kg) were half those used for rats (93-1,500 mg/kg). In the 13-week studies, deaths of 1/10 male and 3/10 female rats dosed at 1,500 mg/kg were compound related; none of the mice died. Body weight gain was reduced in rats at 1,500 mg/kg; there were no significant histopathologic lesions in either rats or mice. The only compound-related effects were ataxia, labored breathing, and lethargy for up to 30 minutes after dosing in rats and mice given the two highest doses and increases in liver weight to body weight ratios for male rats given the three highest doses and for female rats at all doses. Based on the pattern of mortality and the effects on body weight gain in the short-term studies, doses of 375 and 750 mg/kg a-methylbenzyl alcohol were administered in corn oil by gavage, 5 days per week for 103 weeks, to groups of 50 rats and 50 mice of each sex. Two-Year Studies: Significant reduction in body weight gain commenced at weeks 20-30 in high dose male and female rats, and body weights were 20%-30% below those of vehicle controls at study termination. In the low dose groups, body weight reduction occurred only in male rats during the last 10 weeks of the study. After 80 weeks, 60% of the high dose rats and 80%-100% of the low dose and vehicle control rats were alive; thereafter, the number of deaths in the chemically exposed groups increased sharply so that, at the end of 2 years, final survival for vehicle control, low dose, and high dose rats was 35/50; 8/50; and 1/50 for males and 34/50, 25/50, and 11/50 for females. There were a large number of gavage accidents in these studies (1, 9, and 8 for male rats and 1, 4, and 14 for female rats), but these accidents did not contribute to the increase in mortality after week 80, as all but 4 of these occurred earlier. Mortality in the last quarter of the study was thought to be due to the effects of cumulative toxicity of a-methylbenzyl alcohol on a renal excretory system already compromised by aging. Renal nephropathy that commonly occurs during aging was found in all groups of rats, but the severity was greater in male rats dosed with a-methylbenzyl alcohol. In addition, a collection of nonneoplastic lesions (parathyroid hyperplasia, calcification of the heart and glandular stomach, and fibrous osteodystrophy of bone) was found in the dosed male rats; these lesions were probably secondary to mineral imbalance arising from renal dysfunction. Since survival was poor in low and high dose male and high dose female rats, the sensitivity of the study for detecting a carcinogenic effect in these groups was reduced. Despite this limitation, there were dose-related increases in the incidences of renal tubular cell adenomas or adenocarcinomas (combined) in male rats (vehicle control, 0/50; low dose, 2/50; high dose, 5/50). In addition, transitional cell papillomas of the urinary bladder were observed in one high dose male and two high dose female rats. In mice, a reduction in body weight gain was apparent in the high dose groups of males and females. Final survival rates in mice were similar among groups (male: 39/49; 40/50; 28/50; female: 41/50; 41/50; 38/50). No neoplastic or nonneoplastic lesions were attributed to a-methylbenzyl lesions were attributed to a-methylbenzyl alcohol administration in mice of either sex. Genetic Toxicology: a-Methylbenzyl alcohol was not mutagenic in S. typhimurium strains TA98, TA100, TA1535, or TA1537 when tested in the presence or absence of exogenous metabolic activation. a-Methylbenzyl alcohol produced a positive response without activation in the mouse L5178Y/TK+/- lymphoma assay for induction of trifluorothymidine resistance; it was not tested with activation. In cytogenetic tests with CHO cells, a-methylbenzyl alcohol induced chromosomal aberrations in the presence, but not the absence, of metabolic activation; no induction of sister chromatid exchanges was observed in CHO cells after exposure to a-methylbenzyl alcohol. Conclusions: Under the conditions of these 2-year gavage studies, there was some evidence of carcinogenic activityof a-methylbenzyl alcohol for male F344/N rats, as shown by increased incidences of renal tubular cell adenomas and adenomas or adenocarcinomas (combined). There was no evidence of carcinogenic activity for female F344/N rats administered 375 or 750 mg/kg. Renal toxicity characterized by severe nephropathy and related secondary lesions was observed in the dosed rats, and excessive mortality occurred during the last quarter of the studies. Poor survival reduced the sensitivity of the studies for detecting the presence of a carcinogenic response both in chemically exposed groups of male rats and in the high dose group of female rats. There was no evidence of carcinogenic activity of a-methylbenzyl alcohol for male or female B6C3F1 mice administered 375 or 750 mg/kg for 2 years. Synonyms: styrallyl alcohol; styralyl alcohol; a-methylbenzenemethanol; phenylmethylcarbinol; 1-phenethyl alcohol
 ...
PMID:NTP Toxicology and Carcinogenesis Studies of a-Methylbenzyl Alcohol (CAS No. 98-85-1) in F344/N Rats and B6C3F1 Mice (Gavage Studies). 1269 35

N,N-Dimethylaniline is used as a chemical intermediate in the synthesis of dyestuffs. Toxicology and carcinogenesis studies were conducted by administering N,N-dimethylaniline (greater than 98% pure) in corn oil by gavage to groups of F344/N rats and B6C3F1 mice of each sex for 2 weeks, 13 weeks, or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, mouse lymphoma cells, and Chinese hamster ovary (CHO) cells. Two-Week and Thirteen-Week Studies: In the 2-week studies, doses were 94-1,500 mg/kg; deaths of rats and mice were observed in groups given doses of 750 or 1,500 mg/kg. The final mean body weights of male rats that received 375 or 750 mg/kg were 15% or 47% lower than that of vehicle controls; final mean body weights of other groups of rats and mice were similar to those of vehicle controls. Compound-related clinical signs observed included cyanosis in rats and lethargy and tremors in rats and mice. Splenomegaly occurred in nearly all dosed groups of rats and mice, and the incidences were dose related. In the 13-week studies, doses were 32-500 mg/kg; no compound-related deaths occurred. The final mean body weights of male rats that received 250 or 500 mg/kg were 15% or 27% lower than that of vehicle controls. The final mean body weights of all groups of dosed female rats and male and female mice were within 12% of those of vehicle controls. Compound-related clinical signs included lethargy in rats and mice and cyanosis in rats. Splenomegaly was observed in all dosed groups of rats and mice; the severity was dose related. Compound-related extramedullary hematopoiesis and hemosiderosis occurred in the kidney or testis of dosed rats and liver and spleen of dosed rats and mice. Two-year studies were conducted by administering 0, 3, or 30 mg/kg N,N-dimethylaniline in corn oil by gavage, 5 days per week for 103 weeks, to groups of 50 rats of each sex. The lower dose was selected to be one-tenth the higher dose to increase the likelihood that one dose would cause only a minimal nonneoplastic response. Groups of 50 mice of each sex were administered 0, 15, or 30 mg/kg on the same schedule. Body Weight and Survival in the Two-Year Studies: Mean body weights of vehicle control and dosed rats and mice were similar throughout the studies. Survival rates of all respective groups were similar after 2 years, except for the lowered survival of vehicle control female rats (vehicle control, 21/50; low dose 32/50; high dose, 36/50). This may reflect the large number (24/50) of vehicle control female rats killed when observed to be in a moribund state. Final survival for other groups was as follows: male rats--29/50; 32/50; 28/50; male mice-- 34/50; 30/50; 34/50; female mice--35/50; 39/50; 33/50. Nonneoplastic and Neoplastic Effects in the Two-Year Studies: In these 2-year studies, the spleen was the expected site of chemical-related effects. Fatty metamorphosis and fibrosis in the spleen of high dose male rats were increased (fatty metamorphosis: vehicle control, 0/49; low dose, 1/49; high dose, 10/50; fibrosis: 5/49; 2/49; 22/50). Splenic hemosiderosis and hematopoiesis were present at an incidence greater than 85% in all groups of rats; however, the severity of the lesions was greater in dosed groups than in vehicle controls. Sarcomas of the spleen were seen in 3/50 high dose male rats, and an osteosarcoma was seen in another high dose male rat. One additional high dose male rat had a sarcoma of the thymus. Splenic sarcomas are uncommon in corn oil vehicle control male F344/N rats (NTP historical incidence 3/2,081, 0.1%), and thus, these neoplasms in high dose male rats (4/50, 8%) were considered to be chemically related. Lower incidences of mononuclear cell leukemia (which apparently originates in the spleen) were seen in dosed male and female rats than in vehicle controls (male: 13/50; 4/50; 3/50; female: 11/50; 7/50; 0/50). The incidence of squamous cell papillomas of the forestomach in high dose female mice was marginally greater than that in vehicle controls (2/50; 2/50; 8/50). No malignant forestomacin vehicle controls (2/50; 2/50; 8/50). No malignant forestomach neoplasms were observed. Genetic Toxicology: N,N-Dimethylaniline was not mutagenic in S. typhimurium strains TA98, TA100, TA1535, or TA1537 in the presence or absence of exogenous metabolic activation. In the mouse lymphoma assay, N,N-dimethylaniline produced a positive response with and without metabolic activation. In CHO cells, N,N-dimethylaniline induced both sister chromatid exchanges (SCEs) and chromosomal aberrations in the presence of exogenous metabolic activation. Without activation, an increase in chromosomal aberrations was observed, but no increase in SCEs occurred. Conclusions: Under the conditions of these 2-year gavage studies, there was some evidence of carcinogenic activity of N,N-dimethylaniline for male F344/N rats, as indicated by the increased incidences of sarcomas or osteosarcomas(combined) of the spleen. There was no evidence of carcinogenic activity of N,N-dimethylaniline for female F344/N rats given 3 or 30 mg/kg body weight by gavage for 2 years. There was no evidence of carcinogenic activity of N,N-dimethylaniline for male B6C3F1 mice given 15 or 30 mg/kg body weight by gavage for 2 years. There was equivocal evidence of carcinogenic activity of N,N-dimethylaniline for female B6C3F1 mice, as indicated by an increased incidence of squamous cell papillomas of the forestomach. Both rats and mice could have tolerated doses higher than those used in these studies. There were decreased incidences of mononuclear cell leukemia in dosed male and high dose female rats. Compound-related splenic fibrosis, hemosiderosis, and fatty metamorphosis were increased in male rats. Synonyms: dimethylaminobenzene; N,N-dimethylbenzeneamine; dimethylaniline; dimethylphenylamine; N,N-dimethylphenylamine
 ...
PMID:Toxicology and Carcinogenesis Studies of N,N-Dimethylaniline (CAS No. 121-69-7) in F344/N Rats and B6C3F1 Mice (Gavage Studies). 1269 81

2-Amino-4-nitrophenol is used to color semipermanent hair dyes and in the manufacture of mordant dyes for leather, nylon, silk, wool, and fur. 2-Amino-4-nitrophenol was nominated by the National Cancer Institute for toxicology and carcinogenesis studies because of widespread human exposure associated with its manufacture and use. Toxicology and carcinogenesis studies were conducted by administering 2-amino-4-nitrophenol (98% pure) in corn oil by gavage, 5 days per week, to groups of F344/N rats and B6C3F1 mice of each sex in 15-day, 13-week, and 2-year studies. Fifteen-Day and Thirteen-Week Studies: During the 15-day studies, rats and mice received doses of 0, 313, 625, 1,250, 2,500, or 5,000 mg/kg. All rats that received 2,500 or 5,000 mg/kg and all female rats that received 1,250 mg/kg died before the end of the studies. Final mean body weights of chemically exposed rats surviving to the end of the studies were comparable to those of vehicle controls. Diarrhea was observed in all groups of exposed rats except those receiving 313 mg/kg. All mice that received 2,500 or 5,000 mg/kg, 2/5 males and all females that received 1,250 mg/kg, and 1/5 females that received 313 mg/kg died before the end of the studies. Final mean body weights of exposed mice surviving until the end of the studies were comparable to those of vehicle controls. In 13-week studies, F344/N rats and B6C3F1 mice of each sex received 2-amino-4-nitrophenol at doses of 0, 62.5, 125, 250, 500, or 1,000 mg/kg. All rats that received 1,000 mg/kg and 2/10 males and 2/10 females that received 500 mg/kg died before the end of the studies. The final mean body weight of male rats that received 500 mg/kg was reduced 10% compared with that of vehicle controls; final mean body weights of all other surviving exposed rat groups were comparable to those of vehicle controls. Diarrhea and lethargy were observed for rats that received 500 or 1,000 mg/kg. All male mice and most females that received 1,000 mg/kg and 4/10 females that received 500 mg/kg died before the end of the studies. Final mean body weights of chemically exposed mice were comparable to those of vehicle controls. No compound-related clinical signs were observed in mice during the studies. Mineralization of the renal cortex and degeneration of the renal tubular epithelium were observed in male and female rats that received 1,000 mg/kg and in males that received 500 mg/kg. Degeneration and necrosis of the renal tubular epithelium was observed in 5/10 male and 3/10 female mice that received 1,000 mg/kg. Body Weight and Survival in the Two-Year Studies: In the 2-year studies, rats and mice received 2-amino- 4- nitrophenol at doses of 0, 125, or 250 mg/kg. Mean body weights of male rats that received 250 mg/kg were 8%-10% lower than those of vehicle controls throughout most of the 2-year study. Mean body weights of female rats were comparable to those of vehicle controls. Soft stools and occasional diarrhea were observed in chemically exposed rats starting 6 months after the beginning of the studies. Survival of male rats that received 250 mg/kg was markedly lower than that of vehicle controls after week 89 (final survival: vehicle control, 32/50; 125 mg/kg group, 24/50; 250 mg/kg group, 10/50). Survival of female rats was comparable among all groups (final survival: 25/50; 27/50; 31/50). Mean body weights of male and female mice that received 250 mg/kg were comparable to those of vehicle controls; the mean body weights of female mice that received 125 mg/kg were as much as 17% greater than that of vehicle controls. Survival of all mouse groups was comparable during the 2-year studies (final survival: male-- 28/50; 29/50; 23/50; female--28/50; 31/50; 30/50). Nonneoplastic and Neoplastic Effects in the Two-Year Studies: Pigmentation of the small and large intestines was present in exposed rats but not in vehicle controls. Ulcers and erosive lesions of the digestive tract were observed in male rats that received 250 mg/kg and to a lesser extent in male rats that received 125 mg/kg. A carcinoma of the colon occurrkg. A carcinoma of the colon occurred in one male rat that received 250 mg/kg; no other neoplasms were observed in the gastrointestinal tract of rats. No pigmentation, ulcers, or erosive lesions were found in the digestive tract of mice. The severity of nephropathy was markedly greater in exposed male rats than in vehicle controls. Associated with the nephropathy were nonneoplastic lesions indicative of reduced renal function and secondary hyperparathyroidism, including parathyroid hyperplasia, mineralization of various organs, and fibrous osteodystrophy. Renal tubular cell hyperplasia (1/50; 4/48; 5/50) and renal cortical (tubular cell) adenomas (0/50; 1/48; 3/50) occurred in male rats. Renal cortical adenomas are infrequently observed in male F344/N rats (historical incidence, 0.5%). More preputial gland adenomas or carcinomas (combined) were observed in low dose male rats than in vehicle controls (3/50; 10/48; 3/50), whereas the incidences of clitoral gland neoplasms were decreased in dosed female rats (9/50; 6/50; 1/49). Hemangiomas or hemangiosarcomas (combined) occurred in male mice that received 2-amino-4-nitrophenol (0/50; 1/50; 5/50); each tumor was present at a different site. The historical control incidence is 11% at the study laboratory and 6% in 2-year NTP studies. Genetic Toxicology: 2-Amino-4-nitrophenol was mutagenic in Salmonella typhimurium strains TA98 and TA100 with metabolic activation. 2-Amino-4-nitrophenol was not mutagenic in strains TA1535 or TA1537. 2-Amino-4-nitrophenol was mutagenic in the mouse lymphoma L5178Y/TK± assay without metabolic activation. It was not tested with activation. 2-Amino-4-nitrophenol induced sister chromatid exchanges (SCEs) and chromosomal aberrations in Chinese hamster ovary cells in the presence and absence of metabolic activation. Audit: The data, documents, and pathology materials from the 2-year studies of 2-amino-4-nitrophenol were audited at the NTP Archives. The audit findings show that the conduct of the studies is documented adequately and support the data and results given in this Technical Report. Conclusions: Under the conditions of these 2-year gavage studies, there was some evidence of carcinogenic activity of 2-amino-4-nitrophenol for male F344/N rats, as shown by increased incidences of renal cortical (tubular cell) adenomas. The incidences of renal tubular cell hyperplasia were also increased in male rats exposed to 2-amino-4-nitrophenol. The survival of male rats that received 2-amino-4-nitrophenol was reduced compared with survival of vehicle control male rats. There was no evidence of carcinogenic activity of 2-amino-4-nitrophenol for female F344/N rats or for male or female B6C3F1 mice that received 125 or 250 mg/kg per day.
 ...
PMID:NTP Toxicology and Carcinogenesis Studies of 2-Amino-4-Nitrophenol (CAS No. 99-57-0) in F344/N Rats and B6C3F1 Mice (Gavage Studies). 1272 86

Nitrofurazone is a synthetic furan derivative, active against a broad spectrum of bacteria, which has been widely used in veterinary and human medicine. Toxicology and carcinogenesis studies were conducted by feeding diets containing nitrofurazone (99% pure) to groups of F344/N rats and B6C3F1 mice of each sex for 14 days, 13 weeks, or 2 years. Fourteen-Day and Thirteen-Week Studies: Groups of five males and five females of each species were fed diets containing 0, 630, 1,250, 2,500, 5,000, or 10,000 ppm for 14 consecutive days. Early deaths occurred in all groups of rats receiving 5,000 or 10,000 ppm nitrofurazone. The surviving rats in the lower two dose groups gained weight, but weight gain was decreased as the dose of nitrofurazone was increased. Feed consumption by rats of each sex was decreased at all doses above 630 ppm. In all dosed groups, clinical signs of toxicity included rough hair coats and lethargy. At doses of 2,500 ppm and above, rats of each sex exhibited intermittent episodes of seizures and lethargy. All mice that received 2,500, 5,000, or 10,000 ppm nitrofurazone and 3/5 males that received 1,250 ppm died before the end of the 14-day studies; the surviving dosed mice (except females at 630 ppm) lost weight. A dose-related decrease in feed consumption was observed at all doses above 630 ppm. Clinical signs included rough hair coats and convulsive seizures. In the 13-week studies, groups of 10 rats of each sex were given diets containing 0, 150, 310, 620, 1,250, or 2,500 ppm nitrofurazone. No deaths were observed and all animals gained weight, but the magnitude of weight gain was dose dependent with decrements in final mean body weight for the highest dose group reaching 55% in males and 36% in females. Other evidence of chemically related toxicity included convulsive seizures, osteoporosis, degenerative arthropathy, and gonadal hypoplasia in both sexes at the two highest doses. Groups of 10 mice of each sex were given diets containing 0, 70, 150, 310, 620, or 1,250 ppm nitrofurazone for 13 weeks. Early deaths were observed in the two highest dose groups of each sex. The final mean body weights of male and female mice in the 1,250-ppm groups were about 20% lower than those of the controls; weight gains of the other dosed mice were comparable to those of the controls. Stimulus-induced convulsive seizures were observed for all mice in the two highest dose groups. Testicular hypoplasia was observed in the two highest dose groups of male mice. Body Weight and Survival in the Two-Year Studies: Dietary concentrations for the 2-year studies were 0, 310, or 620 ppm for rats and 0, 150, or 310 ppm for mice (50 animals per dose group). Mean body weights of high dose male rats were lower than those of the controls after week 39; mean body weights of low dose male rats and of the controls were comparable throughout the study. Final mean body weights of low and high dose female rats were 9% and 21% lower than those of the controls. Dosed rats consumed less feed than did the controls. The average amount of nitrofurazone consumed per day was approximately 11-12 or 24-26 mg/kg by low or high dose male and female rats. The survival of the high dose group of male rats was lower than that of the controls after week 92 (final survival-- male: control, 33/50; low dose, 30/50; high dose, 20/50; female: 28/50; 37/50; 31/50). Mean body weights of dosed mice were similar to or somewhat greater than those of controls throughout most of the studies. The average daily feed consumption by dosed mice was similar to that of controls. The average amount of nitrofurazone consumed per day was approximately 14-16 or 29-33 mg/kg for low or high dose male and female mice. The survival of the high dose group of male mice was lower than that of the controls after week 88 (final survival-- male: 39/50; 31/50; 27/50; female: 39/50; 40/50; 35/50). In mice of each sex, nitrofurazone administration induced stimulus-sensitive convulsive seizures beginning at week 4 or 5 for high dose mice and week 24 for low dose female mice. These seizures were low dose female mice. These seizures were observed primarily in the first year of the study. Nonneoplastic and Neoplastic Effects in the Two-Year Studies: Degenerative changes involving the vertebral and femoro-tibial (knee) joints were observed at increased incidences in dosed rats. The degenerative changes primarily affected the articular cartilage and were similar to those seen in the 13-week studies. Degeneration of the sternal synchondroses was increased in high dose female rats. The osteoporosis seen in the 13-week studies was not observed in the 2-year studies. Testicular degeneration, characterized by atrophy of the germinal epithelium and aspermatogenesis, was observed at increased incidences in dosed male rats (control, 12/50; low dose, 49/50; high dose, 47/50). Adenomas of the sebaceous glands and trichoepitheliomas or sebaceous adenomas (combined) of the skin were observed in high dose male rats (0/50; 0/50; 5/50). Carcinomas of the preputial gland were increased in dosed male rats (1/50; 8/50; 5/50). The incidences of preputial gland adenomas or carcinomas (combined) in dosed male rats were not statistically greater than that in the controls (9/50; 16/50; 7/50). However, in the low dose group, the incidence is greater than the highest incidence observed in historical untreated control groups (9/50). In addition, hyperplasia of the preputial gland was observed in six low dose male rats in which neither adenomas nor carcinomas occurred. The incidence of mesotheliomas of the tunica vaginalis in low dose male rats was greater than that in the controls (0/50; 7/50; 2/50). Fibroadenomas of the mammary gland occurred at markedly increased incidences in dosed female rats (8/49; 36/50; 36/50). Three adenocarcinomas were also observed (1/49; 0/50; 2/50). Ovarian atrophy (7/47; 44/50; 38/50) and tubular cell hyperplasia of the ovary (1/47; 23/50; 21/50) were observed at markedly increased incidences in dosed female mice. The incidences of benign mixed tumors (0/47; 17/50; 20/50), granulosa cell tumors (1/47; 4/50; 9/50), and granulosa cell tumors or luteomas (combined) (3/47; 6/50; 9/50) of the ovary were increased in exposed female mice. Mononuclear cell leukemia in rats occurred with negative trends (male: 21/50; 23/50; 6/50; female: 15/49; 2/50; 2/50). In female mice, the incidences of adenomas or carcinomas (combined) of the anterior pituitary gland occurred with a negative trend (10/50; 7/50; 2/49). The incidences of testicular interstitial cell tumors were decreased in dosed male rats (45/50; 30/50; 28/50). Genetic Toxicity: Nitrofurazone was mutagenic in Salmonella typhimurium strains TA98 and TA100 both with and without exogenous metabolic activation. The responses in strains TA1535 and TA1537 were more varied: nitrofurazone was mutagenic in strain TA1535 only in the presence of S9 and produced no consistent increase in gene reversions in strain TA1537 with or without S9. In the absence of metabolic activation, nitrofurazone induced forward mutations at the TK+/- locus of mouse L5178Y lymphoma cells; the chemical was not tested with S9. Treatment of cultured Chinese hamster ovary cells with nitrofurazone in the absence of S9 produced a dose-related increase in sister chromatid exchanges and chromosomal aberrations; with S9, sister chromatid exchanges were increased, but no induction of chromosomal aberrations was observed. Audit: The data, documents, and pathology materials from the 2-year studies of nitrofurazone were audited at the NTP Archives. The audit findings show that the conduct of the studies is documented adequately and support the data and results given in this Technical Report. Conclusions: Under the conditions of these 2-year feed studies, there was equivocal evidence of carcinogenic activity of nitrofurazone for male F344/N rats as shown by the occurrence of sebaceous gland adenomas and trichoepitheliomas of the skin, mesotheliomas of the tunica vaginalis, and preputial gland tumors. There was clear evidence of carcinogenic activity of nitrofurazone for female F344/N rats as shown by a markedly increased incidence of fibroadenomas of the mammary gland. There was no evidence of carcinogenic activity for male B6C3F1 mice fed diets containing nitrofurazone at concentrations of 150 or 310 ppm. There was clear evidence of carcinogenic activity of nitrofurazone for female B6C3F1 mice as shown by increased incidences of benign mixed tumors and granulosa cell tumors of the ovary. Administration of nitrofurazone was associated with decreased incidences of mononuclear cell leukemia in male and female rats, testicular interstitial cell tumors in male rats, and pituitary gland neoplasms in female mice. Convulsive seizures in mice of each sex, ovarian atrophy in female mice, testicular degeneration in rats, and degeneration of articular cartilage in rats were all associated with the administration of nitrofurazone. Synonyms: 5-nitro-2-furaldehyde semicarbazone; 2-[(5-nitro-2-furanyl)methylene]hydrazine carboximide Trade Names: Aldomycin; Amifur; Chemfuran; Coxistat; Furacin; Furacinetten; Furaplast; Furazol W; Furesol; Furracoccid; Mammex; Nefco; Nifuzon; Nitrofural; Vabrocid
 ...
PMID:NTP Toxicology and Carcinogenesis Studies of Nitrofurazone (CAS No. 59-87-0) in F344/N Rats and B6C3F1 Mice (Feed Studies). 1273 99


1 2 Next >>