RESUMEN
A serially transplantable perianal gland carcinoma (CAC-9) was developed in nude mice from a hypercalcemic dog that has been maintained through passage 20. Tumor doubling rate of CAC-9 was 3.1 +/- 0.4 days. Mithramycin (MMC) injected intraperitoneally (8 mg/kg) into nude mice bearing CAC-9 markedly decreased the tumor volume 2 weeks post-injection. MMC returned the elevated serum and urine calcium levels in mice with CAC-9 back to similar values as controls. The few remaining viable tumor cells after MMC were large and had numerous aggregations of intermediate filaments that displaced cytoplasmic organelles. Histomorphometric evaluation of lumbar vertebrae reveled no significant differences in bone resorption of nude mice bearing CAC-9 compared to saline-treated controls. This rapidly growing tumor line in nude mice associated with mild hypercalcemia will be a useful animal model to evaluate combinations of chemotherapy for cancer-associated hypercalcemia.
Asunto(s)
Neoplasias de las Glándulas Anales/patología , Carcinoma/patología , Plicamicina/uso terapéutico , Neoplasias de las Glándulas Anales/tratamiento farmacológico , Neoplasias de las Glándulas Anales/ultraestructura , Animales , Carcinoma/tratamiento farmacológico , Carcinoma/ultraestructura , Perros , Ratones , Ratones Desnudos , Trasplante de NeoplasiasRESUMEN
Transmission electron and light microscopy studies were carried out on morphologic characteristics of cellular organelles of normal and different neoplastic cells of hepatoid circumanal glands of 16 dogs. The ultrastructural features of the reserve and transitional cells in the adenomas and carcinomas are highly suggestive of different carcinogenic stimuli for each form of hepatoid circumanal gland neoplasm. The reserve cells, in response to the carcinogenic stimuli, appear to be growing at the expense of the degenerating glandular cells.
Asunto(s)
Adenoma/veterinaria , Neoplasias de las Glándulas Anales/ultraestructura , Carcinoma/veterinaria , Enfermedades de los Perros/patología , Perros/anatomía & histología , Glándulas Perianales/ultraestructura , Adenoma/ultraestructura , Animales , Carcinoma/ultraestructura , Femenino , Hiperplasia/patología , Hiperplasia/veterinaria , Masculino , Microscopía Electrónica , Organoides/ultraestructuraRESUMEN
Adenocarcinomas derived from apocrine glands of the anal sac and associated with persistent hypercalcemia in dogs were composed of tumor cells with numerous profiles of rough endoplasmic reticulum, clusters of free ribosomes, and a prominent Golgi apparatus. Neoplastic cells contained microtubules, microfilaments, tonofibrils, and had two types of electron-dense granules. Large lysosomelike dense bodies ranged from 0.6 to 2.2 microns in diameter and had a poorly delineated limiting membrane. Small granules (150-400 nm in diameter) had a sharply delineated limiting membrane with a narrow submembranous space and a homogeneous dense core. These smaller granules usually were located near the apexes of neoplastic cells, whereas the larger granules were situated near the base of cells. Apocrine cells in glands of the anal sac from control dogs that were in the secretory phase were columnar and had large dilated profiles of rough endoplasmic reticulum. Membranes of the endoplasmic reticulum fused with the plasmalemma and appeared to secrete their product directly into the lumens of acini, characteristic of merocrine secretion. Apical blebs of electron-lucent cytoplasm pinched off from nonneoplastic aprocine cells and were released into glandular lumens. Similar electron-lucent cytoplasmic blebs were present at the apexes of tumor cells. Myoepithelial cells were present between the epithelial cells and basement membrane in normal apocrine glands and were absent in neoplasms derived from these glands. Identification of the contents of the secretory-like granules in tumor cells and characterization of the hypercalcemic factor in the plasma or tumor tissue from dogs with this syndrome will help explain the pathogenesis of hypercalcemia associated with malignancy in animals and man.
Asunto(s)
Adenocarcinoma/veterinaria , Neoplasias de las Glándulas Anales/veterinaria , Enfermedades de los Perros/patología , Hipercalcemia/veterinaria , Neoplasias de las Glándulas Sudoríparas/veterinaria , Adenocarcinoma/complicaciones , Adenocarcinoma/ultraestructura , Neoplasias de las Glándulas Anales/complicaciones , Neoplasias de las Glándulas Anales/ultraestructura , Sacos Anales/ultraestructura , Animales , Gránulos Citoplasmáticos/ultraestructura , Citoesqueleto/ultraestructura , Perros , Retículo Endoplásmico/ultraestructura , Femenino , Aparato de Golgi/ultraestructura , Hipercalcemia/etiología , Ribosomas/ultraestructura , Neoplasias de las Glándulas Sudoríparas/complicaciones , Neoplasias de las Glándulas Sudoríparas/ultraestructuraRESUMEN
Intranuclear cisternal and vesicular structures, bound by a single membrane, were observed for the first time in some glandular "bird's eye" cells of canine circummanal gland carcinomas. The role of these intranuclear structures is not clear. It is suggested that they may be involved in cellular adaptation to an environment of nutrient deficiency, as a result of cell overcrowding.