Repeated high doses of ammonium perfluorooctanoate (APFO) have been reported to affect immune system function in mice. To examine dose-response characteristics in both rats and mice, male CD rats and CD-1 mice were dosed by oral gavage with 0.3-30 mg/kg/day of linear APFO for 29 days. Anti-sheep red blood cell (SRBC) IgM levels, clinical signs, body weights, selected hematology, and lipid parameters, liver weights, spleen, and thymus weights and cell number, selected histopathology, and serum corticosterone concentrations were evaluated. In rats, linear APFO had no effect on production of anti-SRBC antibodies. Ten and 30 mg/kg/day resulted in systemic toxicity as evidenced by decreases in body weight gain to 74 and 37%, and increases in serum corticosterone levels to 135 and 196% of control, respectively. In mice dosed with 10 and 30 mg/kg/day, marked systemic toxicity and stress were observed, as evidenced by a loss in body weight of 3.8 and 6.6 g, respectively (despite a tripling of liver weight), approximately 230% increase in serum corticosterone, and increases in absolute numbers of peripheral blood neutrophils and monocytes with an accompanying decrease in absolute lymphocyte numbers. Immune-related findings at 10 and 30 mg/kg/day that likely represent secondary responses to the systemic toxicity and stress observed at these doses include: decreased IgM antibody production at 10 (20% suppression) and 30 mg/kg/day (28% suppression); decreased spleen and thymus weights and cell numbers; microscopic depletion/atrophy of lymphoid tissue at 10 (thymus) and 30 mg/kg/day (spleen). In summary, no immune-related changes occurred in rats, even at doses causing systemic toxicity. In mice, immune-related changes occurred only at doses causing significant and profound systemic toxicity and stress.

No abstract

No abstract

Abstract. Intestinal carcinoids were diagnosed in three aged dogs. Two of the neoplasms occurred in the rectum and one at the cecocolic junction. Judged by histologic criteria, all three carcinoids were considered to be malignant. Amyloid was present in both rectal tumors. In each tumor the diagnosis was confirmed by the finding of electron-dense intracytoplasmic secretoq granules in the neoplastic cells.