Chemical bursectomy of chickens with colchicine applied to the anal lips.
(17/21)
To induce chemical bursectomy, 30 microliter colchicine dissolved in saline solution (1 mg/ml) was applied on the anal lips of White Leghorn chickens once daily for four consecutive days after hatching. Histologic characteristics of the bursa of Fabricius, spleen, thymus, cecal tonsils, and rectal wall were studied 1-7 days after hatching. Total necrosis of the lymphoid cells and the follicle-associated epithelium in the bursa was observed during the four days of colchicine application. The bursal stroma remained unchanged, and only minor changes were found in the interfollicular surface epithelium. After colchicine application ceased, some regeneration of the epithelium, as evidenced by small epithelial buds, was found. At the end of the observation period the epithelial buds were often covered by the follicle-associated epithelium, which was capable of phagocytizing carbon. However, practically no lymphoid repopulation was seen in the buds. Since this method of colchicine application had no direct effect on other lymphoid organs or on the survival or weight of the chickens, this bursectomy model seems to be a new tool for use in studies of bursal function. (+info)
Ultrastructural evaluation of adenocarcinomas derived from apocrine glands of the anal sac associated with hypercalcemia in dogs.
(18/21)
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. (+info)
Hypercalcemia associated with an adenocarcinoma derived from the apocrine glands of the anal sac.
(19/21)
Clinical, gross, and light microscopic findings are described for 36 dogs, 33 females and three males, with adenocarcinomas arising from the apocrine glands of the anal sac. All tumors had light microscopic features of malignancy and 22 of 23 metastasized to iliac and lumbar lymph nodes. Nine dogs had disseminated metastases, but bone metastases were found in only one dog. Differentiated neoplasms formed secretory acini and tubules lined by tall columnar or cuboidal epithelium. Most neoplasms were histologically bimorphic, with glandular areas and solid nests. Parathyroid glands were atrophic. Hypercalcemia (mean = 16.1 mg/dl) was present in 20 of 22 dogs (90%) and hypophosphatemia (mean = 3.2 mg/dl) in 12 of 17 (71%). Remission of hypercalcemia by tumor ablation and recurrence of hypercalcemia with tumor regrowth suggested that the tumor produced a substance that caused hypercalcemia. This unique clinicopathologic syndrome is characterized by hypercalcemia in old, predominantly female, dogs with an adenocarcinoma arising from the apocrine glands of the anal sac. (+info)
Lipids of the anal sac secretions of the red fox, Vulpes vulpes and of the lion, Panthera leo.
(20/21)
Lion anal sac secretion were found to be richer in lipids and to contain more complex less uniform mixtures of lower moleculas weight lipids then the anal sac of the red fox. In the lion, homologous series of 1-alkylglycerols and 2-hydroxy-fatty acids were identified. Phenylacetic, 3-phenylpropionic, and related hydroxylated acids were also observed. Gas-liquid chromatography profiles of fox anal sac secretion lower molecular weight lipids were found to be less variable in their major constituents and to be dominated by relatively few large peaks, mainly (derivatized) fatty acids. Indole was also identified. Free cholesterol, and occasionally, stanols were observed in fox and lion secretions. In the red fox, total cholesterol levels averaged 0.93 mg/g (% free, 56.4), n = 5. Findings are discussed in relation to histological and anatomical similarities and differences between the anal sacs of the lion and the fox and in the context of the role of these secretions in chemical communication. (+info)
Dependence of humoral hypercalcemia of malignancy on parathyroid hormone-related protein expression in the canine anal sac apocrine gland adenocarcinoma (CAC-8) nude mouse model.
(21/21)
Circulating parathyroid hormone-related protein (PTHrP) is the primary humoral factor in dogs with spontaneous humoral hypercalcemia of malignancy (HHM) and adenocarcinomas derived from apocrine glands of the anal sac. A canine apocrine adenocarcinoma model of HHM in nude mice (CAC-8) was developed and characterized. After 32 passages in vivo, a spontaneous variant of the tumor (CAC-8 Lo Ca) that has altered cellular morphology and that fails to induce HHM in tumor-bearing nude mice has been discovered. The hypercalcemic and nonhypercalcemic tumor lines were compared by tumor weight, effect on body weight, serum calcium concentration, plasma PTHrP concentration, histopathology, expression of PTHrP protein by radioimmunoassay and immunohistochemistry, and expression of PTHrP mRNA by in situ hybridization and northern blot analysis. Messenger RNA expression for other factors and cytokines known to alter PTHrP secretion or bone resorption in vivo, including tumor necrosis factor alpha (TNF alpha), interleukin (IL)-1, IL-6, and transforming growth factor beta (TGF beta), were also measured in the adenocarcinomas. There was no significant difference in weight of individual tumors. Nude mice bearing the CAC-8 (Lo Ca) tumor maintained normal body weight as compared with non-tumor-bearing control mice. In contrast, mice with the CAC-8 (Hi Ca) tumor had markedly decreased body weights. The CAC-8 (Hi Ca) tumor-bearing mice had severe hypercalcemia (mean = 13.4 mg/dl) and increased plasma concentrations of PTHrP (30.4 pM), whereas the CAC-8 (Lo Ca) tumor-bearing mice had a mean serum calcium concentration of 10.1 mg/dl and mildly increased PTHrP concentrations (5.7 pM) as compared with control mice (9.0 mg/dl and 1.0 pM, respectively). The original tumor (CAC-8 [Hi Ca]) is a well-differentiated adenocarcinoma, whereas the variant tumor (CAC-8 [Lo Ca]) is a solid carcinoma with both polygonal and spindle-shaped cells. The CAC-8 (Lo Ca) tumor had decreased PTHrP mRNA expression and protein synthesis. Messenger RNA expression of TGF beta, TNF alpha, IL-1, and IL-6 was similar in both tumors and was consistent with the central role of PTHrP in the induction of hypercalcemia in this animal model. (+info)