Splenic myeloid metaplasia, histiocytosis, and hypersplenism in the dog (65 cases)

Antifertility effects of Oldenlandia affinis in male rats - a preliminary study

Antifertility effects of an aqueous leaf extract of Oldenlandia affinis on male rats were investigated. The extract was administered intraperitoneally in sexually mature male rats at a dose of 24 mg/rat (n=8) for a total of eight injections over a 4 week period. There was a decrease in testis weights but all other accessory sex organs and vital organ weights were not affected by treatment with O. affinis extract. Testis histology revealed fewer spermatozoa or azoospermic seminiferous tubules in treated animals compared to controls with no change in neither tubule thickness nor Sertoli cell structure. O. affinis treatment caused a 17% decrease in sperm motility but there was no change in cauda epididymal sperm counts. However, serum testosterone levels decreased significantly (P<0.05) in the experimental group (602.4 ± 57 ng/dL) compared to controls (808.9 ± 55 ng/dL). These preliminary results show that the aqueous leaf extract of O. affinis suppresses fertility parameters in male rats.

Chronic murine typhoid fever is a natural model of secondary hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a hyper-inflammatory clinical syndrome associated with neoplastic disorders especially lymphoma, autoimmune conditions, and infectious agents including bacteria, viruses, protozoa and fungi. In both human and veterinary medicine, hemophagocytic histiocytic disorders are clinically important and frequently fatal. HLH in humans can be a primary (familial, autosomal recessive) or secondary (acquired) condition, with both types generally precipitated by an infectious agent. Previously, no mouse model for secondary HLH has been reported. Using Salmonella enterica serotype Typhimurium by oral gavage to mimic naturally-occurring infection in Sv129S6 mice, we characterized the clinical, hematologic and morphologic host responses to disease thereby describing an animal model with the clinico-pathologic features of secondary HLH as set forth by the Histiocyte Society: fever, splenomegaly, cytopenias (anemia, thrombocytopenia), hemophagocytosis in bone marrow and spleen, hyperferritinemia, and hypofibrinogenemia. Disease severity correlates with high splenic and hepatic bacterial load, and we show disease course can be monitored and tracked in live animals. Whereby secondary HLH is known to occur in human patients with typhoid fever and other infectious diseases, our characterization of a viable natural disease model of secondary HLH offers an important means to elucidate pathogenesis of poorly understood mechanisms of secondary HLH and investigation of novel therapies. We characterize previously unreported secondary HLH in a chronic mouse model of typhoid fever, and novel changes in hematology including decreased tissue ferric iron storage that differs from classically described anemia of chronic disease. Our studies demonstrate S. Typhimurium infection of mice is a natural infectious disease model of secondary HLH that may have utility for elucidating disease pathogenesis and developing novel therapies.

Nódulos fibro-histiocíticos no baço de uma cadela: relato de caso

Descreve-se a ocorrência de múltiplos nódulos fibro-histiocíticos no baço de uma cadela Rottweiler, de sete anos. O diagnóstico foi feito por histopatologia e confirmado por imunoistoquímica positiva para ED1, CD18, vimentina e lisozima. O animal foi sacrificado três meses após o diagnóstico, por severo agravamento dos sinais clínicos.

Canine hemophagocytic histiocytic sarcoma: a proliferative disorder of CD11d+ macrophages

Histiocytic disorders of dogs include histiocytoma, localized histiocytic sarcoma (HS), disseminated HS (malignant histocytosis), and the reactive histiocytoses: cutaneous and systemic. A common element to these diseases is proliferation of dendritic cells (DC) of either Langerhans cell (epithelial DC) or interstitial DC lineage. In this report, 17 dogs with hemophagocytic HS are described. Breeds affected included Bernese Mountain Dog (6), Golden Retriever (4), Rottweiler (3), Labrador Retriever (2), a mixed-breed dog, and a Schnauzer, which were from 2.5 to 13 years old. The dogs presented with Coombs negative responsive anemia in 16/17 dogs (94%), thrombocytopenia in 15/17 dogs (88%), hypoalbuminemia in 16/17 dogs (94%), and hypocholesterolemia in 11/16 dogs (69%). All dogs died or were euthanized. The clinical course ranged from 2 to 32 weeks (mean 7.1 weeks). Diffuse splenomegaly with ill-defined masses was consistently present. Microscopic lesions were prevalent in spleen, liver, lung, and bone marrow. Metastasis occurred by insidious intravascular invasion with minimal mass formation. Histiocytes were markedly erythrophagocytic and accompanied by foci of extramedullary hemopoiesis. Cytologically, the histiocytes varied from well differentiated to atypical, with atypia more prevalent in spleen than bone marrow. These tumors arose from splenic red pulp and bone marrow macrophages, which expressed major histocompatibility complex class II and the beta2 integrin, CD11d. They had low and/or inconsistent expression of CD1 and CD11c, which are dominantly expressed by canine nonhemophagocytic HS of DC origin. Canine histiocytic proliferative diseases now encompass proliferation of all members of the myeloid histiocytic lineage: Langerhans cells, interstitial DC, and macrophages.

Benzo(a)pyrene-induced anemia and splenomegaly in NZB/WF1 mice

Benzo(a)pyrene (BaP), a polycyclic aromatic hydrocarbon, is a known immunomodulator. At high doses, BaP is immunosuppressive but at low doses it can enhance the immune response. Studies were conducted to determine if BaP would exacerbate the development of autoimmune disease in genetically prone NZB/WF1 mice. Five week old female NZBW/F1 mice were exposed dermally to 5, 20 and 40 mg/kg BaP for 30 days. Vehicle mice were exposed to an acetone:olive oil mixture for 30 days. BaP did not increase total IgG, anti-DNP-HSA or anti-dsDNA antibody levels. However, hematological evaluation revealed a decrease in erythrocyte number, hemoglobin and hematocrit and an increase in mean corpuscular volume and red cell distribution width in the 20 and 40 mg/kg dose groups. Liver and spleen weights were increased in the high dose groups; however, an increase in spleen cell number was not observed. Histopathological evaluation revealed splenic red pulp expansion in a mouse treated with 40 mg/kg BaP. An increase in splenic CFU-e production was observed in mice treated with 20 and 40 mg/kg BaP. A decrease in splenic total B cells, total T cells, CD4(+) and CD8(+) T cells was observed in mice treated with 20 and 40 mg/kg BaP. An increase in splenic null cells (non-T, non-B cells) was also observed in the high dose groups, consistent with extramedullary hematopoiesis. Coombs' tests, flow cytometry and an immune-mediated hemolysis assay indicated that the anemia was not autoimmune-mediated. Although no change was observed in the percentage of reticulocytes in these animals, further bone marrow analysis is needed to determine if the anemia is due to bone marrow suppression, possibly caused by BaP exposure, or chemical-induced hemolysis, perhaps contributed to by erythrocyte fragility inherited from a parent strain, NZB, which spontaneously develops autoimmune hemolytic anemia and subsequent splenomegaly.

Cytologic evaluation of benign and malignant hemophagocytic disorders in canine bone marrow

Canine hemophagocytic disorders were studied to better understand the cytologic features that differentiate benign and malignant disease. Of 286 canine clinical bone marrow reports evaluated retrospectively, 13 (4.5%) noted at least 3% hemophagocytic macrophages. Macrophages comprised between 6% and 44% of nucleated bone marrow cells. Clinical diagnoses for dogs with hemophagocytic disorders included malignant histiocytosis (n = 2), myelodysplastic syndromes (n = 4), round cell neoplasia (n = 2), immune-mediated disorders (n = 2), and idiopathic hemophagocytic syndrome (n = 3). Differentiation of benign and malignant forms of histiocytosis was problematic. Two dogs with a diagnosis of hemophagocytic syndrome had macrophages with atypical features similar to those described for malignant histiocytosis. Furthermore, only 2 of 11 dogs with presumably benign hemophagocytic disorders had exclusively mature macrophages in bone marrow. Other dogs had variable numbers of large reticular-type cells characterized by lacy chromatin, anisocytosis, anisokaryosis, and prominent and/or multiple nucleoli. On the basis of these results, cytomorphologic evaluation of bone marrow alone may not be adequate to consistently differentiate benign and malignant forms of hemophagocytic disorders.