Scanning electron microscopic study of bovine leukemic cells

Scanning electron microscopic observation of (i) leukemic cells in peripheral blood and tumor tissues of 11 cattle with bovine leukosis (adult form, n = 5; calf form, n = 2; and thymic form, n = 4) and (ii) peripheral lymphocytes from 2 cattle with persistent lymphocytosis and from 3 healthy cattle revealed morphologic differences of cell surface structures among various forms of bovine leukosis. These differences indicated an interrelationship of cell surface morphologic features between peripheral lymphocytes and tumor cells. Leukemic cells from cattle with the thymic and calf forms characteristically had a smooth surface. In cells from cattle with the adult form, the majority of abnormal cells in the peripheral blood, possessed numerous elongated microvilli on the cell surface, whereas tumor cells in the tissue were pleomorphic with a long villous, plicated surface or had stubby projections. Most of the peripheral lymphocytes from cattle with persistent lymphocytosis were characterized by a dense arrangement of elongated microvilli on the cell surface.     

Scanning electron microscopic study of the functional anatomy of the porcine oviductal mucosa

A three-dimensional model has not been clearly established for the porcine oviductal mucosa. The oviducts of 12 cyclic sows were examined by Scanning Electron Microscopy to study the structure and nature of the mucosal arrangement of the oviduct. Epithelial cyclic changes were also studied. The oviductal infundibulum is an asymmetric funnel-shaped structure surrounding the ostium, in which a wide and a narrow side can be distinguished. The mucosa is more complex in the narrow side, showing numerous and tortuous longitudinal primary folds, while the mucosa becomes simpler in the wide side. Around the ostium abdominale wide secondary folds form cul-de-sacs, with their opening pointing in ovarian direction. Areas between folds throughout the lumen of the oviduct show a high-degree of complexity. Inter-fold spaces are occupied by a system of irregular grooves and pockets, with the presence of basal crypts in the caudal oviduct. Marked variations were observed in the oviductal epithelium depending on the oviductal segment, basal or apical areas of the folds, and phase of the oestrous cycle. Cyclical changes were observed in the infundibulum and ampulla, so that prominent and numerous ciliated cells lined apical areas of the folds in the follicular phase; whereas secretary cells were predominant throughout all areas of epithelial surface in the luteal phase. The oestrous cycle phase appeared do not affect the epithelial population cells of the caudal segments of the oviduct: ciliated and secretory cells uniformly lined apical and basal areas of the folds. The topography of the oviduct provides a complex system of regulation, which may influence not only the passage of cells, but also movement of fluid within the oviductal canal.     

Chicken anemia agent: an electron microscopic study

Particles of chicken anemia agent (CAA) negatively stained with uranyl acetate were found to be 26.5 nm in diameter. The surface detail evident on the particles indicated that the virus capsid was composed of 32 structural subunits arranged as in a class P = 3 icosahedron with a triangulation number of 3. Using mouse monoclonal antibodies to CAA and a gold-labeled goat anti-mouse IgG, CAA-specific structures were observed by thin-section electron microscopy in infected MDCC-MSB1 cells and in thymic lymphocytes from experimentally infected chicks. These consisted of electron-dense, granular, non-membrane-bound nuclear inclusions, which were often ring-shaped, and cytoplasmic accumulations of microtubules. Aggregates of virus-like particles were sometimes observed in the nuclei of infected MDCC-MSB1 cells. The nucleolar involvement that is characteristic of the morphogenesis of parvoviruses was not observed with CAA.     

Detection of the hyaluronan receptor CD44 in the bovine oviductal epithelium

Hyaluronan is involved in fundamental reproductive events such as sperm storage in the female reproductive tract, fertilization, and early embryo development, these functions are presumably mediated by its major cell surface receptor, CD44. The present study was conducted to investigate the presence and localization of CD44 in the bovine oviductal epithelium, using immunohistochemical and Western blot methods on tissue sections and epithelial cell extracts collected from the uterotubal junction (UTJ), isthmus, and ampulla of animals in the oestrus or luteal phase of the oestrous cycle. While positive immunolabelling for CD44 was found on the ad-luminal surface and supra-nuclear region of epithelial cells in all tubal segments investigated, in the UTJ, there were epithelial cells in which the entire cytoplasm positively stained. We found no differences in terms of CD44-positive staining between the different stages of the oestrous cycle. Presence of CD44 was detected by Western blotting in the tubal epithelium as a single band at 200 kDa. Although it appeared in all tubal segments, the expression of CD44 protein was more accentuated in the sperm reservoir (UTJ) than in the other segments. This is the first time CD44 has been detected in the epithelium of the tubal sperm reservoir in cattle, suggesting a pathway for the action of hyaluronan in this segment.     

Experimental hamster enteritis: an electron microscopic study.

Hamster enteritis (HE) was experimentally produced in weanling hamsters by orally inoculating healthy hamsters with suspensions of ilea obtained from hamsters with HE. Control groups of hamsters were inoculated orally with suspensions of ilea from healthy hamsters. Electron microscopy was done on ilea from 6 control hamsters, 31 hamsters with experimentally produced HE, and 4 hamsters with naturally occurring HE. Ultrastructural changes were not observed in the absorptive epithelium of control animals. Two different intracytoplasmic bacterial organisms were observed in epithelial cells of hamsters with experimentally produced HE. Organisms that were observed early in the disease process were identified as Escherichia coli. Organisms ultrastructurally similar to Campylobacter spp were observed later in the disease and were only within hyperplastic epithelial cells. The hyperplastic ileal epithelium of hamsters with naturally occurring HE contained campylobacter-like organisms.     

Canine hepatic neuroendocrine carcinoma: an immunohistochemical and electron microscopic study

Ten dogs with neuroendocrine carcinoma of the liver were selected for inclusion in the study. Clinical signs were anorexia (7), vomiting (5), polydipsia/polyuria (3), icterus (2), lethargy (2), weight loss (2), paresis (1), ataxia (1), weakness (1), collapse (1), and urinary tract infection (1). Hematologic and biochemical abnormalities included anemia (2/8), leukocytosis (4/8), high liver enzyme activity (serum alkaline phosphatase, 7/9; alanine transaminase, 7/9; aspartate transaminase, 8/9), and high total bilirubin (6/9). Grossly, the tumors were diffuse, involving all liver lobes in six dogs, and two dogs had various-sized nodules in addition to diffuse involvement. Histologically, there were eight tumors with solid or trabecular pattern (group A), one tumor with cords or rows of neoplastic cells (group B), and one tumor with multiple rosette-like structures (group C). Immunohistochemical studies revealed that all 10 neoplasms were positive for at least one of the endocrine markers used: neuron-specific enolase (NSE; 8/10), synaptophysin (5/10), and chromogranin-A (3/10). A panel of NSE, chromagranin-A, and synaptophysin detected 100% of the tumors in our series. Electron microscopy confirmed the diagnosis by the presence of intracytoplasmic neurosecretory granules in the two examined cases. Our results show that neuroendocrine markers commonly used in humans can be used for the diagnosis of hepatic neuroendocrine carcinoma in dogs, preferably a panel of synaptophysin, chromagranin-A, and NSE because chromogranin-A alone is not as useful in dogs as in humans.     

Immunoferritin and immune electron microscopic study of bovine herpesvirus strain DN-599.

Intracellular antigens of strain DN-599 bovine herpesvirus were detected in the cytoplasm and the nucleus of infected bovine embryonic kidney cells by the indirect immunoferritin (IF) technique. Specific tagging was observed in viral envelope and capsids. Aggregates of viral particles heavily coated with antibody were seen by immune electron microscopy (IEM).     

Olfactory neuroepithelioma in a dog: an immunohistochemical and electron microscopic study

A case of olfactory neuroepithelioma was investigated electron microscopically and immunohistochemically. The tumor mass was found in the nasal cavities of a 10-year-old female dog, which showed epistaxis, nasal discharge and facial swelling. The tumor tissue consisted of tubular structure of cuboidal to columnar cells and compactly arranged nests of small cells surrounded by a fibrovascular stroma. Mitotic figures were frequently observed. Immunohistochemically, the tumor cells frequently showed positive for neurofilament protein, synaptophysin and/or carnosine in addition to keratin. Ultrastructurally, tight junction was observed between the tumor cells. No dense-cored secretory granules were shown in the tumor cells. These findings indicated that the present tumor had neuronal and epithelial features probably originating from the olfactory epithelium.     

A scanning electron microscopic study of the vascular system of the bovine hind limb claw

The vascular organisation of the hind limb claws of clinically normal cattle was studied using scanning electron micrographs of plastic corrosion casts. The microvasculature of the dermal papillae and lamellae was demonstrated. A consistent vascular pattern was observed in the dermal papillae of the periople, coronary margin, sole and bulb. Ultrastructurally, the papillar vasculature consisted of a central artery and vein surrounded by a fine network of interconnected capillaries and venules. Arteriovenous anastomoses, connecting the central artery and vein, and peripherally situated arteriovenous loops were recognised in the terminal papillae of the white zone only. Arteriovenous anastomoses, focal enlargements and distension of the capillary bed were located within the interior half of the dermal lamellae. Numerous arteriovenous anastomoses were present throughout the entire dermis of the claw and were situated predominantly at the base of the dermal papillae and lamellae. The anastomoses and focal capillary enlargements may influence the blood flow in normal conditions and may play a significant role in the pathophysiology of bovine laminitis and sole ulceration.     

Scanning electron microscopic characterization of bovine coronavirus plaques in HRT cells

The ecology of cytopathic expression of bovine coronavirus (BCV) in HRT-18 cells was analyzed within virus-induced plaques by scanning electron microscopy. Virus replication was cytocidal for many HRT-18 cells, a function enhanced in the presence of trypsin. A monolayer of cells remained that imparted a characteristic turbidity to the plaque. These structurally normal, lysis-resistant cells did not stain with fluorescent antibodies specific for BCV antigens, failed to adsorb virus particles or mouse erythrocytes in contrast to the susceptible cells. The survival of cells in the plaque interior reflects a non-productively infected population with evidence of viral persistence.     

The scanning electron and light microscopic structure of bovine tactile hair

Bovine tactile hairs in skin samples from the lateral side of the upper lip were examined using scanning electron and light microscopy. The root of these hairs has a variable length and is surrounded by a large sinus located between the internal and the external dermal sheath. With a prominent thickness, the external dermal sheath forms the external wall of the tactile hair and contains many nerves some of which extend into trabeculae. Trabeculae projecting from the internal dermal sheath and attaching to the external dermal sheath with two or more branches are present in the entire sinus. The trabeculae are interconnected by connective tissue sheets that support the integrity of the trabecular organization. The sinus surfaces as well as trabeculae are lined by endothelia. As a result, the bovine tactile hair is truly a cavernous type of tactile hair with a well organized microscopic anatomy. Thus, the bovine tactile hair most likely plays an important role in relatively immobile and insensitive bovine lips.     

Electron microscopic study of the porcine choroid plexus epithelium

The choroid plexus (CP) is a highly vascularized organ in the brain ventricles which acts as the main producer of cerebrospinal fluid (CSF). A study of the surface ultrastructure of the porcine CP was performed using scanning and transmission electron microscopy. The vascular walls of the capillaries were fenestrated. Epiplexus cells of different morphology were abundant on top of the epithelial surface. Two types of epithelial cells were present, characterized by the presence or absence of microvilli. Some epithelial cells contained cilia while other cells had large secretory protrusions called blebs. In the choroid epithelium of the lateral ventricles, some cells with large depressions were present. Cells with peduncles, such as recently discovered in the buffalo, could not be recognized. The variability of the choroidal surface structures clearly indicates the active role of the CP in the formation and maintenance of the CSF and its components.