No abstract

No abstract

The bovine haemal nodes are lymphatic organs with haemal circulation. The blood circulates inside of them through virtual cavities named sinuses. In these sinuses there is passage of cells and particulate materials from parenchyma to sinuses and vice versa. For this passage temporal overtures exist in the sinus walls. The sinus wall is composed of endothelial cells, basal membrane and reticular cells. Our results have demonstrated that type IV collagen was one of the basal membrane constituents in bovine haemal nodes and by this constitution a dynamic equilibrium of the sinus walls was permitted.

Abstract. A young male Bernese mountain dog presented with neurologic abnormalities consisting of nonambulatory tetraparesis, generalized tremors, and depressed mental status. At necropsy only a mild enlargement of the lateral ventricles was seen. The histologic examination revealed the presence of eosinophilic deposits consistent with Rosenthal fibers (RFs) throughout the white matter of the central nervous system. There was also a marked proliferation of abnormally large astrocytes and limited myelin changes. RFs were most prominent in perivascular, subpial, and subependymal areas, where they were perpendicularly located, producing a pallisaded arrangement. Immunohistochemically, RFs were strongly positive for glial fibrillary acidic protein (GFAP), and when they were examined ultrastructurally they appeared as electron-dense amorphous masses located within the processes of astrocytes, most particularly in the perivascular feet. The histologic and immunohistochemical findings of this canine case were consistent with the published neuropathologic descriptions of Alexander disease in humans and in a few dogs, a rare condition that in humans has been shown to be caused by dominant mutations in the GFAP gene.Key words: Alexander disease; Bernese mountain dog; encephalopathy; GFAP; leukodystrophy; Rosenthal fibers; transmission electron microscopy.A 4-month-old male Bernese mountain dog presented to the Hospital Veterinario Rof Codina with a 3-week history of progressive tetraparesis and tremors, particularly of the hind limbs. The dog had been treated with prednisone (Dacortin, Merck Farma y Química, S. A., Barcelona, Spain) at 0.5 mg/kg per os twice a day for 3 days, but it did not respond to the therapy and the condition worsened rapidly. On admission, the neurologic examination revealed nonambulatory tetraparesis, generalized tremors and depressed mental status. Postural reactions were difficult to evaluate because of generalized weakness, but they were considered to be abnormally slow. Spinal cord reflexes were decreased in all 4 limbs, but cranial nerve function and muscle tone were preserved. The laboratory data revealed normal urine and blood values. A multifocal involvement of the central nervous system was suspected, and, therefore, sampling of cerebrospinal fluid (CSF) was performed by cerebellomedullary cisternal puncture. CSF analysis showed 5 cells/ml (reference range, ,8 cells/ml), total protein concentration of 21 mg/dl (reference range, ,25 mg/dl), and absence of neutralizing antibodies against canine distemper virus. Because of the deteriorated neurologic status, and at the request of the owner, the dog was euthanatized, and a complete necropsy was performed.Gross lesions were found only in the brain, with a moderate enlargement of the lateral ventricles. The brain and the cranial portion of the cervical spinal cord were fixed by immersion in 10% buffered formalin, and then representative coronal slices were embedded in paraffin according to standard laboratory procedures.Paraffin sections (4-5 mm...

An external pinkish growing mass that emerged from the right nostril of an adult goldfish Carassius auratus L. was evaluated by means of light microscopy and immunohistochemistry. The neoplasm presented a well-developed fibrovascular stroma associated with solid cell nests and a large number of Flexner-Wintersteiner rosettes. Myelinated fibres were observed around them. Neoplastic cells showed a prominent degree of nuclear atypia and low mitotic activity. The latter was in agreement with the low reactivity of tumour cells to anti-proliferating cell nuclear antigen antibody. Immunohistochemistry also revealed anti-neuronal nitric oxide synthase, anti-S100 protein, antineuropeptide Y, and anti-cytokeratin immunoreactivity in tumour cells as well as in normal olfactory epithelium of goldfish control sections. Histopathological and immunohistochemical findings strongly suggest a diagnosis of an olfactory neuroblastoma (ONB). To our knowledge this is the first description of ONB in goldfish. KEY WORDS: Tumour · Olfactory neuroblastoma · Goldfish · Carassius auratus · Histopathology · Immunohistochemistry Resale or republication not permitted without written consent of the publisherDis Aquat Org 96: [61][62][63][64][65][66][67][68] 2011 MATERIALS AND METHODSAn adult goldfish Carassius auratus L. was referred to a private veterinary clinic located in Rosario City, Argentina. The specimen showed an external pinkish growing mass emerging from the right nostril. The roughly shaped mass of approximately 0.5 cm in diameter was excised, fixed in 10% v/v buffered formaldehyde solution and submitted to the Diagnostic Pathology Service of the School of Veterinary Sciences-National University of Rosario, Argentina. The sample was dehydrated in a graded series of ethanol and embedded in paraffin wax. Sections of 3 to 5 µm in thickness were stained using haematoxylin and eosin, combined periodic acid-Schiff (PAS)/Alcian blue, the Grimelius technique and Tolivia staining.In order to define the origin of the presumptive tumour, an immunohistochemical study was carried out. Unless otherwise stated, all incubations were performed at room temperature in a humid chamber, and all washing procedures consisted of 3 successive 5 min immersions in 0.1 M phosphate-buffered saline (PBS). Endogenous peroxidase activity was blocked by incubation in Peroxidase Blocking Reagent (Dako) for 30 min, and after a rinse in PBS, antigens were exposed by heating under pressure in different buffer solutions or by incubating the samples with proteolytic enzymes depending on the primary antibody employed ( Table 1). The sections were subsequently washed again with PBS, treated with 3% skimmed milk powder for 15 min to block non-specific antibody binding, incubated with the primary antibody as indicated in Table 1, washed with PBS, and incubated for 30 min with anti-mouse or anti-rabbit EnVision+ System Labelled Polymer-HRP (DakoCytomation). After further rinsing, the sections were finally developed using 3, 3-diaminobenzidine tetrahydrochloride...

Nitric oxide (NO) is a free radical gas with important roles in the host's immune response against viral infections. In this study, we examined the kinetics and distribution of nitric oxide synthase (NOS) expression during the early steps of infection of the porcine nervous system by the alphaherpesvirus pseudorabies virus (PRV). To this end, we examined changes in the expression of the three major NOS isoforms, neuronal NOS (nNOS), endothelial NOS (eNOS) and inducible NOS (iNOS), by immunohistochemistry in the trigeminal ganglia and brain of pigs inoculated intranasally with a virulent PRV strain. The results obtained show that infection of the porcine nervous system by PRV induced a rapid and progressive increment in NOS expression that coincided in timing, location, and magnitude with those of virus propagation in the nervous tissue. A major finding of this study was that PRV caused not only nNOS and iNOS induction in a variety of cell types, but also eNOS up-regulation in endothelial cells and neurons; therefore, all possible sources of NO are activated and probably contribute to the overproduction of NO during infection with the neurotropic alphaherpesvirus PRV in its natural host.

No abstract

Haemal nodes are capsulated, lymphoid organs with haemal circulation. Their parenchyma is distributed in primary and secondary lymphatic nodes in the cortical and medullar zones. In these zones the lymphatic tissue may adopt a cord-like shape and it is composed by plasma cell, macrophages and B and T lymphocytes. Blood circulates through the sinuses situated underneath the capsule, around the trabeculae and in the marrow.