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Ginkgo biloba extract has been used primarily as a medicinal agent in the treatment or prevention of cardiovascular and cerebrovascular dysfunction. Ginkgo biloba extract was nominated for study by the National Cancer Institute because of its widespread use as an herbal supplement to promote mental function and the limited availability of toxicity and carcinogenicity data. Furthermore, one of the major ingredients in Ginkgo biloba extract, quercetin, is a known mutagen. The Ginkgo biloba extract used in the current studies was procured from a supplier known to provide material to United States companies and contained 31.2% flavonol glycosides, 15.4% terpene lactones (6.94% bilo-balide, 3.74% ginkgolide A, 1.62% ginkgolide B, 3.06% ginkgolide C), and 10.45 ppm ginkgolic acid. Male and female F344/N rats and B6C3F1/N mice were administered Ginkgo biloba extract in corn oil by gavage for 3 months or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, Escherichia coli, and mouse peripheral blood erythrocytes. 3-MONTH STUDY IN RATS: Groups of 10 male and 10 female rats were administered 0, 62.5, 125, 250, 500, or 1,000 mg Ginkgo biloba extract/kg body weight in corn oil by gavage, 5 days per week for 14 weeks. Additional groups of 10 male and 10 female rats (clinical pathology study) were administered the same doses, 5 days per week for 23 days. All rats survived to the end of the study. Mean body weights of all dosed groups were similar to those of the vehicle control groups. Liver weights of all dosed groups of males and females were significantly greater than those of the vehicle control groups. The incidences of hepatocyte hypertrophy in all dosed groups of males and in 500 and 1,000 mg/kg females were significantly greater than those in the vehicle control groups; there was a dose-related increase in severity of this lesion in males. Hepatocyte fatty change occurred in all dosed males. The incidences of thyroid gland follicular cell hypertrophy were significantly increased in 500 and 1,000 mg/kg males and in 1,000 mg/kg females. The incidences of pigmentation in the olfactory epithelium of the nose were significantly increased in 500 and 1,000 mg/kg males and in females administered 125 mg/kg or greater. 3-MONTH STUDY IN MICE: Groups of 10 male and 10 female mice were administered 0, 125, 250, 500, 1,000, or 2,000 mg Ginkgo biloba extract/kg body weight in corn oil by gavage, 5 days per week for 14 weeks. One female mouse in the 1,000 mg/kg group died of a dosing accident during week 11. Mean body weights of 2,000 mg/kg females were significantly less than those of the vehicle control group. Ruffled fur was observed in two 1,000 mg/kg males between weeks 7 and 8 and all 2,000 mg/kg males between weeks 5 and 9. Liver weights of 250 mg/kg or greater males and all dosed groups of females were significantly greater than those of the vehicle control groups. Kidney weights of 2,000 mg/kg males were significantly less than those of the vehicle control group. The Markov transition matrix analyses indicate female mice in the 2,000 mg/kg group had a significantly higher probability of extended estrus than did the vehicle control females. The incidences of hepatocytic hypertrophy were significantly increased in males and females in the 250 mg/kg or greater groups. Significantly increased incidences of focal hepatocytic necrosis occurred in 1,000 and 2,000 mg/kg males. The incidences of hyaline droplet accumulation in the respiratory epithelium of the nose were significantly increased in 500 mg/kg males and 1,000 and 2,000 mg/kg females. In the olfactory epithelium of the nose, the incidences of hyaline droplet accumulation were significantly increased in the 125 (female only), 500, and 1,000 mg/kg groups. Incidences of atrophy of the olfactory epithelium were significantly increased in the 1,000 mg/kg groups. The incidences of pigment accumulation in macrophages in the olfactory epithelium were significantly increased in males in the 500 mg/kg or greater groups and in 1,000 and 2,000 mg/kg females. 2-YEAR STUDY IN RATS: Groups of 50 male and 50 female rats were administered 0, 100, 300, or 1,000 mg Ginkgo biloba extract/kg body weight in corn oil by gavage, 5 days per week for 104 or 105 (females) weeks. Additional groups of 10 male and 10 female rats (special study) were administered the same doses, 5 days per week for 14 weeks. Survival of 1,000 mg/kg males was significantly less than that of the vehicle controls. At week 14, all dosed groups of males and 1,000 mg/kg females had increased levels of thyroid stimulating hormone compared to those of the vehicle control groups. There were no significant decreases in the levels of triiodothyronine or total thyroxine. Mean body weights of 300 mg/kg males and females were less (10% or more) than those of the vehicle controls after week 93, and those of 1,000 mg/kg males and females were less after week 89. Clinical findings included ruffled fur in seven, eight, and 10 males in the 100, 300, and 1,000 mg/kg groups, respectively, beginning at week 89; four vehicle control males also had ruffled fur. Liver weights were significantly increased in all dosed groups of special study rats at 14 weeks. In the liver at 2 years, incidences of hepatocellular adenoma were slightly increased in 100 and 300 mg/kg males. Significantly increased incidences of nonneoplastic lesions at 2 years included hepatocyte hypertrophy and bile duct hyperplasia in all dosed groups of males and females, focal fatty change in all dosed groups of females, cystic degeneration in 100 and 1,000 mg/kg males, and oval cell hyperplasia and necrosis in 1,000 mg/kg males. In the thyroid gland, incidences of follicular cell adenoma were slightly increased in 300 and 1,000 mg/kg males and 300 mg/kg females. Single incidences of follicular cell carcinoma occurred in the 300 and 1,000 mg/kg female groups. There were significantly increased incidences of follicular cell hypertrophy in all dosed groups of males and females and follicle hyperplasia in all dosed groups of males. In the nose, adenoma of the respiratory epithelium occurred in two females receiving 300 mg/kg. Except for respiratory epithelium hyperplasia in 100 mg/kg females, the incidences of transitional epithelium and respiratory epithelium hyperplasia were significantly increased in all dosed groups of males and females. Except for olfactory epithelium respiratory metaplasia in 100 mg/kg females, the incidences of atrophy, respiratory metaplasia, nerve atrophy, and pigmentation were significantly increased in the olfactory epithelium of all dosed groups of males and females. Incidences of goblet cell hyperplasia in the respiratory epithelium were significantly increased in 300 and 1,000 mg/kg males and females, and incidences of chronic active inflammation were significantly increased in 1,000 mg/kg males and females. The incidence of submucosa fibrosis was significantly increased in 1,000 mg/kg males. The incidences of mononuclear cell leukemia in 300 and 1,000 mg/kg males were significantly greater than that in the vehicle controls. Dose-related increased severity of kidney nephropathy was noted in all dosed groups of males. 2-YEAR STUDY IN MICE: Groups of 50 male and 50 female mice were administered 0, 200, 600, or 2,000 mg Ginkgo biloba extract/kg body weight in corn oil by gavage, 5 days per week for 104 weeks. Survival of 600 and 2,000 mg/kg males was significantly less than that of the vehicle controls; survival of 600 mg/kg females was significantly greater than that of the vehicle controls. Mean body weights of 600 and 2,000 mg/kg males were less (10% or more) than those of the vehicle controls after weeks 85 and 77, respectively; mean body weights of 2,000 mg/kg females were generally less than those of the vehicle controls between weeks 17 and 69 and after week 93. In the liver, there were significantly increased incidences of hepatocellular adenoma in all dosed groups of females, hepatocellular carcinoma in all dosed groups of males and 2,000 mg/kg females, and hepatoblastoma in all dosed groups of males and 600 and 2,000 mg/kg females. The increased incidences of these neoplasms were primarily due to increased incidences of multiple adenoma, carcinoma, and hepatoblastoma. Except for the incidences of hepatocellular carcinoma or hepatoblastoma (combined) in 200 and 600 mg/kg females, the incidences of hepatocellular adenoma or carcinoma (combined), hepatocellular carcinoma or hepatoblastoma (combined), and hepatocellular adenoma, hepatocellular carcinoma, or hepatoblastoma (combined) were significantly increased in all dosed groups of males and females. Significantly increased incidences of nonneoplastic liver lesions included hypertrophy in all dosed groups of males and females, erythrophagocytosis in all dosed groups of males and in 600 and 2,000 mg/kg females, hematopoietic cell proliferation, inflammation, and necrosis in 600 and 2,000 mg/kg males, and cytoplasmic vacuolization, eosinophilic focus, and mixed cell focus in all dosed groups of females. In the thyroid gland, two incidences each of follicular cell adenoma occurred in the 600 and 2,000 mg/kg male groups. The incidence of follicle hyperplasia was significantly increased in 2,000 mg/kg males, and the incidences of follicular cell hypertrophy were significantly increased in 2,000 mg/kg males and 600 and 2,000 mg/kg females. In the forestomach, the incidences of inflammation, epithelium hyperplasia, and epithelium hyperkeratosis were significantly increased in all dosed groups of males and in 2,000 mg/kg females; the incidences of epithelium ulcer were significantly increased in 2,000 mg/kg males and females. GENETIC TOXICOLOGY Ginkgo biloba extract was mutagenic in S. typhimurium strains TA98 and TA100, and in E. coli strain WP2 uvrA/pKM101, with and without exogenous metabolic activation. (ABSTRACT TRUNCATED)

N,N-dimethyl-p-toluidine was nominated for toxicology and carcinogenesis studies by the National Cancer Institute based on the potential for human exposure through its use in dental materials and bone cements and the lack of toxicity and carcinogenicity data. Male and female F344/N rats and B6C3F1/N mice were administered N,N-dimethyl-p-toluidine (greater than 99% pure) in corn oil by gavage for 3 months or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium and Escherichia coli, mouse peripheral blood, and mouse and rat liver. 3-MONTH STUDY IN RATS: Groups of 10 male and 10 female rats were administered 0, 62.5, 125, 250, 500, or 1,000 mg N,N-dimethyl-p-toluidine/kg body weight in corn oil by gavage, 5 days per week for 14 weeks. Additional groups of 10 male and 10 female rats (clinical pathology study) were administered the same doses, 5 days per week for 25 days. On day 88, blood was collected from core study rats for hemoglobin and methemoglobin analyses only. All 1,000 mg/kg male and female rats and one 500 mg/kg male rat died by study day 3. Mean body weights of all surviving dosed groups of males and females were significantly less than those of the vehicle controls. Clinical findings associated with exposure to N,N-dimethyl-p-toluidine included cyanosis, abnormal breathing, and lethargy in groups administered 250 mg/kg or greater. Methemoglobinemia appeared to be the primary hematologic toxic response, and many other lesions could be explained as secondary to methemoglobin formation including Heinz body formation; a macrocytic, hypochromic, responsive anemia; and increased hematopoietic cell proliferation in the spleen and bone marrow. In general, hematologic changes were dose-related and occurred at both evaluated timepoints in all dosed groups. Anemia was evidenced by decreases in hematocrit values, hemoglobin concentrations, and erythrocyte counts; erythrocyte macrocytosis was characterized by increases in mean cell volume and mean cell hemoglobin values; erythrocyte hypochromia was evidenced by decreases in mean cell hemoglobin concentration values; and an erythropoietic response to the anemia was characterized by substantially increased reticulocyte and nucleated erythrocyte counts. Liver weights of all surviving dosed groups of males and females were significantly greater than those of the vehicle controls. Kidney weights of all surviving dosed groups of females were significantly greater than those of the vehicle controls. There were significant decreases in left cauda epididymis and left epididymis weights in 250 mg/kg males. There was a dose-related decrease in the number of cycling females, with only four females in the 250 mg/kg group having regular cycles and females in the 125 and 250 mg/kg groups spending a significantly higher proportion of time in extended diestrus compared to the vehicle control group. In the surviving groups of rats, there were significantly increased incidences of pigmentation in the liver of all dosed groups, hepatocyte hypertrophy in groups administered 125 mg/kg or greater, and hepatocyte necrosis in 62.5, 250, and 500 mg/kg females. In the olfactory epithelium of the nose, there were dose-related increases in the incidences and severities of degeneration in all dosed groups and significantly increased incidences of metaplasia in the 250 and 500 mg/kg groups. In the respiratory epithelium of the nose, there were significantly increased incidences of hyperplasia and squamous metaplasia in all of the groups administered 125 mg/kg or greater. The incidences of glandular hyperplasia of the nose were significantly increased in males and females administered 125, 250, or 500 mg/kg. In the spleen, there were significantly increased incidences of capsule fibrosis, congestion, mesothelial hypertrophy, and lymphoid follicle atrophy primarily in groups administered 125 mg/kg or greater. Hematopoietic cell proliferation and pigmentation were increased in severity in treated groups. In the kidney, there were significantly increased incidences of nephropathy (females), pigmentation (males and females), papillary necrosis (males and females), and mineralization (males). Other treatment-related lesions included inflammation of the forestomach in males, mesenteric lymph node atrophy in females, and bone marrow hyperplasia in males and females. 3-MONTH STUDY IN MICE: Groups of 10 male and 10 female mice were administered 0, 15, 30, 60, 125, or 250 mg N,N-dimethyl-p-toluidine/kg body weight in corn oil by gavage, 5 days per week for 14 weeks. All 250 mg/kg male and female mice (except for one male mouse) died before day 10, and three males and two females administered 125 mg/kg died before the end of the study. The final mean body weight of 125 mg/kg males and the mean body weight gains of 125 mg/kg males and females were significantly less than those of the vehicle controls. Clinical findings associated with administration of N,N-dimethyl-p-toluidine included abnormal breathing, thinness, lethargy, cyanosis, and ruffled fur in 125 and 250 mg/kg males and females. Methemoglobinemia appeared to be the primary hematologic toxic response; however there were less severe erythron changes compared to the 3-month study in rats. In females, no erythron changes were detected up to 125 mg/kg. In males, inconsistent and minor decreases in hematocrit values, hemoglobin concentrations, and erythrocyte counts, and increased reticulocyte counts occurred in groups administered 60 mg/kg or greater. Methemoglobin values were minimally increased in males and females administered 30 mg/kg or greater. Heinz bodies were slightly increased in 60 mg/kg females, 125 mg/kg males and females, and the one surviving 250 mg/kg male; Heinz body formation was considered secondary to methemoglobin formation. Liver weights of all dosed groups of mice were significantly greater than those of the vehicle controls. In the surviving groups of mice, there were significantly increased incidences of bronchiolar epithelium degeneration, bronchiolar epithelium regeneration, and peribronchiolar chronic active inflammation in the lung of 125 mg/kg groups, and histiocytic infiltrates of the alveoli in 125 mg/kg females. In the nose, there were significantly increased incidences of glandular hyperplasia and olfactory epithelium metaplasia in the 125 mg/kg groups and olfactory epithelium degeneration in 60 mg/kg females and 125 mg/kg males and females. In the thymus, the incidences of thymocyte necrosis in the 125 mg/kg groups were significantly increased. In the liver, the severities of cytoplasmic vacuolization of the hepatocytes were increased in dosed groups of males and females. 2-YEAR STUDY IN RATS: Groups of 50 male and 50 female rats were administered 0, 6, 20, or 60 mg N,N-dimethyl-p-toluidine/kg body weight in corn oil by gavage, 5 days per week for 104 or 105 weeks. Additional groups of 10 male and 10 female rats (clinical pathology study) were administered the same doses for 86 days. Survival of 60 mg/kg males was significantly less than that of the vehicle controls. Mean body weights of 60 mg/kg males and females were more than 10% less than those of the vehicle controls after week 61 and week 33, respectively. Clinical findings included signs of pallor in 60 mg/kg females and hyperactivity and boxing behavior in 20 mg/kg females and 60 mg/kg males and females. The hematology findings at the 3-month timepoint were consistent with those in the 3-month study in rats which indicated that methemoglobinemia was the primary hematologic toxic response. In the 20 and 60 mg/kg groups, there were dose-related decreases in hematocrit values, hemoglobin concentrations, and erythrocyte counts. There were similar trends toward erythrocyte macrocytosis and hypochromia and increased erythropoiesis as seen in the 3-month study. While the magnitudes of the erythron decreases were not sufficient to classify the responses as anemias, the patterns of the erythron changes were identical to those in the 3-month study. In the liver of 60 mg/kg males and females, there were significantly increased incidences of hepatocellular carcinoma and hepatocellular adenoma or hepatocellular carcinoma (combined). Numerous nonneoplastic liver lesions occurred in dosed males and females primarily in the 20 and 60 mg/kg groups. In the nose, there were significantly increased incidences of transitional epithelium adenoma and transitional epithelium adenoma or carcinoma (combined) in 60 mg/kg males; transitional epithelium adenoma also occurred in female rats administered 6 or 60 mg/kg. In the nose, there were significantly increased incidences of nonneoplastic lesions in the olfactory, respiratory, and transitional epithelia of dosed rats. These lesions occurred with the greatest incidence and severity in the 60 mg/kg groups. The incidences of inflammation and nerve atrophy were significantly increased in males and females administered 60 mg/kg. There were increased incidences of follicular cell adenoma or carcinoma (combined) of the thyroid gland in all dosed groups of males, and an increased incidence of follicular cell adenoma in 20 mg/kg females. In the spleen, there were significantly increased incidences of hematopoietic cell proliferation in all dosed groups of males and females. The incidences of congestion and mesothelial hypertrophy of the capsule were significantly increased in 60 mg/kg males and all dosed groups of females. There were also significantly increased incidences of capsular fibrosis and atrophy of the lymphoid follicle in the 60 mg/kg groups. The incidences of pigmentation were significantly increased in all dosed groups of males and in 60 mg/kg females. In all dosed groups of female rats, there were significantly increased incidences of nephropathy. (ABSTRACT TRUNCATED)

Unlabelled: [structure--see text] Elmiron, a white powder, is the sodium salt of pentosan polysulfate, a semisynthetic sulfated polyanion composed of beta-D-xylopyranose residues with biological properties similar to heparin. Elmiron is used in the United States for the relief of urinary bladder pain associated with interstitial cystitis. Because of its stimulating effect on fibrinolysis, Elmiron has been used clinically in the treatment and prevention of thrombotic disorders. The United States Food and Drug Administration nominated Elmiron for toxicology and carcinogenicity testing by the National Toxicology Program because of its orphan drug status. Male and female F344/N rats and B6C3F1 mice received Elmiron, which met product specifications provided by the manufacturer, in deionized water by gavage for 2 weeks, 3 months, or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, rat and mouse bone marrow cells, and mouse peripheral blood erythrocytes. 2-WEEK STUDY IN RATS: Groups of five male and five female rats were administered 0, 33, 111, 333, 1,000, or 3,000 mg Elmiron/kg body weight in deionized water by gavage, 5 days per week, for 16 days. Elmiron administration had no effect on survival or body weight gain. Activated partial thromboplastin time was significantly increased in 3,000 mg/kg rats. Liver weights of 3,000 mg/kg rats were significantly greater than those of the vehicle controls. Hepatocellular cytoplasmic vacuolization occurred in all 3,000 mg/kg females. 2-WEEK STUDY IN MICE: Groups of five male and five female mice were administered Elmiron in deionized water by gavage at doses of 0, 33, 111, 333, 1,000, or 3,000 mg/kg, 5 days per week, for 16 days. All mice survived to the end of the study. Mean body weight gains of male mice administered 333 mg/kg or greater were significantly greater than that of the vehicle control group. Liver weights of 1,000 and 3,000 mg/kg males were significantly increased. 3-MONTH STUDY IN RATS: Groups of 10 male and 10 female rats were administered Elmiron in deionized water by gavage at doses of 0, 63, 125, 250, 500, or 1,000 mg/kg, 5 days per week, for 14 weeks. No deaths were attributed to administration of Elmiron. Mean body weights of 125 mg/kg males were less than those of vehicle controls and the mean body weights of all dosed groups of females were greater. Hematology results indicated that Elmiron, at the doses selected, induced a minimal erythron decrease and leukocyte and platelet count increases that may have been secondarily related to the inflammatory lesions observed in various tissues of rats. Liver and spleen weights of males administered 250 mg/kg or greater were significantly increased. Liver weights of all dosed groups of females, and kidney, lung, and spleen weights of 1,000 mg/kg females were significantly increased. Histiocytic cellular infiltration, chronic active inflammation, and ulcers of the rectum occurred in most 500 and 1,000 mg/kg rats. Administration of Elmiron was associated with the presence of vacuolated histiocytes in the mandibular and mesenteric lymph nodes, lung, kidney, and liver of male and female rats. Histochemical investigations of the vacuolated histiocytes indicated the presence of neutral and acidic mucins and lipid material within the vacuoles. Transmission electron microscopy identified these vacuoles as lysosomal structures that exhibited a variety of contents. 3-MONTH STUDY IN MICE: Groups of 10 male and 10 female mice were administered Elmiron in deionized water by gavage at doses of 0, 63, 125, 250, 500, or 1,000 mg/kg, 5 days per week, for 14 weeks. One 250 mg/kg female mouse was sacrificed moribund on day 84; all other mice survived to the end of the study. Mean body weights of dosed groups were similar to those of the vehicle control groups. Hematology results indicated that Elmiron, at the doses selected, induced a minimal erythron decrease and leukocyte and platelet count increases that may have been secondarily related to the inflammatory lesions observed in various tissues of mice. in various tissues of mice. Liver weights of 500 mg/kg males and 1,000 mg/kg males and females, and spleen weights of 1,000 mg/kg males were significantly increased. Histiocytic cellular infiltration and chronic active inflammation of the rectum occurred in most 1,000 mg/kg mice. Administration of Elmiron was associated with the presence of vacuolated histiocytes in the mandibular and mesenteric lymph nodes, liver, and spleen of males and females. Histochemical investigations of the vacuolated histiocytes indicated the presence of neutral and acidic mucins within the vacuoles. Transmission electron microscopy identified these vacuoles as lysosomal structures that exhibited a variety of contents. 2-YEAR STUDY IN RATS: Groups of 50 males and 50 females were administered Elmiron in deionized water by gavage at doses of 0, 14, 42, or 126 mg/kg to males and 0, 28, 84, or 252 mg/kg to females, 5 days per week, for 104 or 105 weeks. Survival of all dosed groups of rats was similar to that of the vehicle control groups. Mean body weights of all dosed groups were similar to those of the vehicle controls throughout the 2-year study. Microscopically, myxomatous changes were present in the rectum of 56% of 126 mg/kg males and 83% of 252 mg/kg females. The incidences of chronic active focal alveolar inflammation of the lung were increased in all dosed groups. The incidences of histiocytic cellular infiltration of the mesenteric lymph nodes were increased in 42 and 126 mg/kg males and in 84 and 252 mg/kg females, and lymphohistiocytic hyperplasia was present in the spleen of 126 mg/kg males and 252 mg/kg females. 2-YEAR STUDY IN MICE: Groups of 50 males and 50 females were administered Elmiron in deionized water by gavage at doses of 0, 56, 168, or 504 mg/kg, 5 days per week, for 104 or 105 weeks. Survival of all dosed groups of mice was similar to that of the vehicle control groups. Mean body weights of males were similar to those of vehicle controls. Mean body weights of 504 mg/kg females were progressively less than those of the vehicle controls during the second year of the study. Increased incidences of hemangiosarcomas of the liver and hepatocellular neoplasms were observed in male and female mice. The incidences of hemangiosarcomas in the 504 mg/kg groups exceeded the historical control ranges for males and females; both the trend and the incidence in the 504 mg/kg groups were significant for males. Hemangiosarcomas in males and females were attributed to Elmiron administration. The incidence of hepatocellular adenoma in 504 mg/kg females was significantly increased and exceeded the historical control range; the trends for hepatocellular adenoma and for hepatocellular adenoma or carcinoma (combined) were also significant in females and were attributed to Elmiron administration. There was also a marginal increase in the incidences of hepatocellular neoplasms in male mice, which may have been associated with Elmiron administration. Malignant lymphomas occurred with a positive trend in female mice; the incidence in the 504 mg/kg group was also significantly increased and matched the upper limit of the historical control range. These malignant lymphomas may have been associated with Elmiron administration. Nonneoplastic lesions related to the administration of Elmiron occurred in the liver, rectum, mesenteric lymph node, and spleen of 504 mg/kg mice and to a lesser extent in 168 mg/kg mice. These lesions were similar to those observed in the 3-month study., Genetic Toxicology: Elmiron was not mutagenic in S. typhimurium strains TA97, TA98, TA100, or TA1535 with or without induced hamster or rat liver S9 enzymes. No increases in the frequency of micronucleated polychromatic erythrocytes were seen in bone marrow cells of rats or mice administered Elmiron by gavage three times at 24-hour intervals. No significant alterations in the frequency of micronucleated normochromatic erythrocytes were seen in peripheral blood samples from male or female mice administered Elmiron for 3 months by gavage., Conclusions: Under the conditions of these 2-year gavage studies, there was no evidence of carcinogenic activity of Elmiron in male F344/N rats administered 14, 42, or 126 mg/kg or in female F344/N rats administered 28, 84, or 252 mg/kg. There was some evidence of carcinogenic activity of Elmiron in male B6C3F1 mice based on increased incidences of liver hemangiosarcoma. The increased incidences of hepatocellular neoplasms in male mice may have been related to Elmiron administration. There was some evidence of carcinogenic activity of Elmiron in female B6C3F1 mice based on the increased incidences of liver hemangiosarcoma and hepatocellular neoplasms. The increased incidences of malignant lymphomas in female mice may have been related to Elmiron administration. Elmiron administration caused increased incidences of nonneoplastic lesions (presence of vacuolated histiocytes) of the rectum, lung, mesenteric lymph node, and spleen (males) in rats and of the liver, rectum, mesenteric lymph node, and spleen in mice.

Unlabelled: [structure--see text] Triethanolamine is widely used in the manufacturing of household detergents and polishes, textiles, agricultural herbicides, mineral and vegetable oils, paraffin and waxes, pharmaceutical ointments, petroleum demulsifiers, synthetic resins, plasticizers, adhesives, and sealants. It is used as a chemical intermediate for anionic and nonionic surfactants, a vulcanization accelerator, a humectant and softening agent and in many other industrial applications. The National Cancer Institute nominated triethanolamine for study because of its widespread use in cosmetics and other consumer products, its high potential for worker exposure due to its many industrial uses, and its potential for conversion to the carcinogen N-nitrosodiethanolamine. Previous 3-month and 2-year studies of triethanolamine were conducted by the National Toxicology Program in F344/N rats and B6C3F1 mice; results from the 2-year rat study indicated equivocal evidence of carcinogenic activity based on a marginal increase in the incidence of renal tubule adenoma (NTP, 1991). Interpretation of the results from the 2-year study in mice was complicated by Helicobacter hepaticus infection, prompting a repeat 2-year study in mice. Male and female B6C3F1 mice received triethanolamine (greater than 99% pure) by dermal application for 2 years; a study of absorption, distribution, metabolism, and excretion was performed in additional mice. Genetic toxicology studies were conducted in Salmonella typhimurium, cultured Chinese hamster ovary cells, Drosophila melanogaster, and mouse peripheral blood erythrocytes. 2-YEAR STUDY: Groups of 50 male and 50 female mice received dermal applications of 0, 200, 630, or 2,000 mg/kg (males) and 0, 100, 300, or 1,000 mg/kg (females) triethanolamine in acetone, 5 days per week, for 104 (males) or 104 to 105 (females) weeks. Survival of all dosed groups was similar to that of the vehicle control groups. Body weights of 2,000 mg/kg males were less than those of the vehicle controls from weeks 17 to 37 and at the end of the study; body weights of dosed groups of females were similar to those of the vehicle controls throughout the study. Treatment-related clinical findings included skin irritation at the site of application, which increased with increasing dose and was more severe in males than in females. Gross lesions observed at necropsy included nodules and masses of the liver in dosed females. The incidences of hepatocellular adenoma and hepatocellular adenoma or carcinoma (combined) were significantly increased in all dosed groups of females. The incidence of hemangiosarcoma of the liver in 630 mg/kg males was marginally increased. The incidences of eosinophilic focus in all dosed groups of mice were greater than those in the vehicle controls. Gross lesions observed at necropsy included visible crusts at the site of application in all dosed groups of mice. Treatment-related epidermal hyperplasia, suppurative inflammation, ulceration, and dermal chronic inflammation occurred at the site of application in most dosed groups of mice, and the incidences and severities of these lesions generally increased with increasing dose., Genetic Toxicology: Triethanolamine was not mutagenic in any of the in vitro or in vivo tests. It did not induce mutations in Salmonella typhimurium, and no induction of sister chromatid exchanges or chromosomal aberrations was noted in cultured Chinese hamster ovary cells exposed to triethanolamine. These in vitro tests were all conducted with and without S9 metabolic activation. Triethanolamine did not induce sex-linked recessive lethal mutations in germ cells of adult male Drosophila melanogaster exposed by feeding or injection. No increase in the frequency of micronucleated erythrocytes was observed in peripheral blood samples of male or female mice that received dermal applications of triethanolamine for 13 weeks., Conclusions: Under the conditions of this 2-year dermal study, there was equivocal evidence of carcinogenic activity of triethanolamine in male B6C3F1 mice based on the occurrence of liver hemangiosarcoma. There was some evidence of carcinogenic activity in female B6C3F1 mice based on increased incidences of hepatocellular adenoma. Exposure to triethanolamine by dermal application resulted in increased incidences of eosinophilic focus of the liver in males and females. Dosed mice developed treatment-related nonneoplastic lesions at the site of application.

Unlabelled: Riddelliine belongs to a class of toxic pyrrolizidine alkaloids and is isolated from plants of the genera Crotalaria, Amsinckia, and Senecio that grow in the western United States. Cattle, horses, and sheep that ingest these plants succumb to their toxic effects. Riddelliine residues have been found in meat, milk, and honey, and the plants may contaminate human food sources. Riddelliine was nominated for study by the Food and Drug Administration because of its potential for human exposure and its economic impact on the livestock industry and because the toxicity of other pyrrolizidine alkaloids suggests riddelliine may be carcinogenic. Male and female F344/N rats and B6C3F1 mice received riddelliine (approximately 92% pure) by gavage. Female rats and male and female mice were dosed for 2 years; due to high mortality, the study in male rats was terminated at week 72. In vitro genetic toxicology studies were conducted in Salmonella typhimurium and in cultured Chinese hamster ovary (CHO) cells. In addition, riddelliine was evaluated in vivo for induction of micronuclei in mouse bone marrow and peripheral blood erythrocytes and for induction of S-phase DNA synthesis and unscheduled DNA synthesis in the liver of rats and mice. Riddelliine-induced DNA adduct levels were determined in liver tissue obtained from female rats admininstered riddelliine for 3 or 6 months. 2-YEAR STUDY IN RATS: Groups of 50 male and 50 female rats were administered 0 or 1 mg riddelliine/kg body weight in sodium phosphate buffer by gavage 5 days per week; additional groups of 50 female rats received 0.01, 0.033, 0.1, or 0.33 mg/kg. A wide dose range was used in female rats to better characterize the dose-response curve. Females were dosed for 105 weeks; due to high mortality, male rats were terminated at week 72. All but three 1 mg/kg males died before week 70, and all 1 mg/kg females died before week 97. Mean body weights of 1 mg/kg males and females were less than those of the vehicle controls throughout most of the study. The only clinical finding related to riddelliine administration was a general debilitation of the animals prior to death. Hemangiosarcomas were present in the liver of 86% of males and 76% of females in the 1 mg/kg groups, and this neoplasm was considered the cause of the large number of early deaths in these groups. The incidences of hepatocellular adenoma and mononuclear cell leukemia in 1 mg/kg males and females were significantly increased. Nonneoplastic lesions related to riddelliine treatment occurred in the liver and kidney of males and females. Analyses of liver tissue from female rats treated with riddelliine for 3 or 6 months yielded eight DNA adducts; these were the same as DNA adducts formed in vitro by the metabolism of riddelliine by human liver microsomes in the presence of calf thymus DNA. 2-YEAR STUDY IN MICE: Groups of 50 male and 50 female mice were administered riddelliine in sodium phosphate buffer by gavage at doses of 0 or 3 mg/kg, 5 days per week, for 105 weeks; additional groups of 50 male mice received 0.1, 0.3, or 1 mg/kg for 105 weeks. A wide dose range was used in male mice to better characterize the dose-response curve. Survival of males and females administered 3 mg/kg was significantly less than that of the vehicle controls. Mean body weights of 3 mg/kg mice were less than those of the vehicle controls throughout most of the study. Hemangiosarcomas of the liver were present in 62% of males in the 3 mg/kg group. The incidences of hepatocellular neoplasms occurred with negative trends in male mice and were significantly decreased in 3 mg/kg females. The incidences of alveolar/bronchiolar neoplasms in 3 mg/kg females were significantly increased. Nonneoplastic lesions related to riddelliine administration occurred in the liver and kidney of males and females and in the lung and arteries (multiple tissues) of females., Genetic Toxicology: Riddelliine was mutagenic in S. typhimurium strain TA100 with, but not without, S9 activation; no significant mutagenic activity was detected in strain TA98 or TA1535,ed in strain TA98 or TA1535, with or without S9. A small, dose-related increase in mutant colonies seen in strain TA97 with S9 was judged to be equivocal. Riddelliine induced sister chromatid exchanges in cultured CHO cells with and without S9. Chromosomal aberrations were induced in CHO cells only in the presence of S9. Following 4 or 13 weeks of daily gavage treatment with riddelliine, no increases in the frequency of micronucleated erythrocytes were noted in the peripheral blood of male or female B6C3F1 mice. Use of a single intraperitoneal injection protocol, however, produced a small but significant increase in the frequency of micronucleated eryth-rocytes in peripheral blood of male Swiss mice 48 hours after injection; bone marrow analysis 24 hours after injection demonstrated a small but insignificant increase in the frequency of micronuclei. Unscheduled DNA synthesis was detected in cultured hepatocytes from male and female rats and mice following 5 or 30 days of riddelliine treatment by gavage. In addition, an S-phase DNA synthesis was observed in cultured hepatocytes of male and female rats treated for either time period., Conclusions: Under the conditions of these studies, there was clear evidence of carcinogenic activity of riddelliine in male and female F344/N rats based primarily on increased incidences of hemangiosarcoma in the liver. The increased incidences of hepatocellular adenoma and mononuclear cell leukemia in male and female rats were also considered to be treatment related. There was clear evidence of carcinogenic activity of riddelliine in male B6C3F1 mice based on increased incidences of hemangiosarcoma in the liver. There was clear evidence of carcinogenic activity in female B6C3F1 mice based on increased incidences of alveolar/bronchiolar neoplasms. Administration of riddelliine by gavage resulted in nonneoplastic lesions in the liver and kidney of male and female rats; the liver and kidney of male and female mice; and the lung and arteries (multiple tissues) of female mice. Decreased incidences of hepatocellular neoplasms in male and female mice were related to riddelliine administration.