Morphological and histochemical observations on renal microbodies in cats.

The diaminobenzidine method for catalase showed two distinct morphological populations of renal microbodies in healthy mature cats of both sexes. Microbodies in the proximal convoluted tubules, which in this species also contain abdundant neutral lipids, were polyhedral and had distinct marginal plates. Those in the remaining renal tubules, which are lipid-free, were rounder and less uniform in size. Both forms of microbodies had homogenous granular matrices without nuceloides. The morphological variations of the microbodies may depend on their association with renal lipids. The cat may serve as a model to explore functional or pathological relationships between microbodies and fat metabolism.     

Canine cutaneous histiocytoma: ultrastructural and cytochemical observations.

Five canine cutaneous histiocytomas were studied by electron microscopy and esterase cytochemistry. The tumor cells contained irregular nuclei, characteristic lysosomal granules, and perinuclear microfilaments. The cells showed activity with alpha-naphthyl acetate esterase stains. These characteristics are evidence that this tumor originates from the mononuclear phagocyte system.     

Murine cytomegalovirus glomerulonephritis: clinical and ultrastructural observations.

This investigation was initiated to study and correlate the clinical and ultrastructural aspects of glomerulonephritis induced in the laboratory mouse by the intraperitoneal injection of a sublethal dose of murine cytomegalovirus. An attempt was made to ascertain the pathogenesis of the glomerular changes and the resultant viremia. Murine cytomegalovirus infection caused an acute transient glomerulonephritis in young female mice of the HA/ICR strain. Mice that survived a sublethal inoculation of homogenized infected gland developed transient proteinuria and excreted tubular casts. The murine cytomegalovirus infection resulted in a glomerular lesion that was selective for the mesangial cell. After entering the mesangial cell by phagocytosis the virus replicated in the nucleus and was excreted into the channel of the mesangial matrix, with extension toward the periphery of the capillary loop and adjacent to the urinary space. Virus particles were rarely found in the glomerulus after the 5th day of infection and chronic renal disease was not observed.     

Lymphocyte populations and adhesion molecule expression in bovine tonsils

Bovine tonsils are mucosal-associated lymphoid tissue (MALT) located at the entry of the pharynx where both inhaled and ingested antigens can induce an immune response. This study was conducted to determine the lymphocyte populations and adhesion molecule expression in the palatine tonsil (PT) and pharyngeal tonsil (PhT) of adult cattle and compare them with typical MALT (discrete Peyer's patches, PP) and a peripheral lymph node (parotid lymph node, PLN). The distribution of various lymphocyte subsets was determined in situ by immunofluorescence, and their proportions were determined by multicolor flow cytometry. The tonsils were similar to PP in the proportions of B- and T-cells (25-32% T-cells, 39-45% B-cells), and T cell subpopulations (CD4, CD8, and gammadelta). The PP contained the highest proportion of memory T-helper cells with beta7 integrin (30.3%+/-5.4), the tonsils intermediate (PT: 19.8%+/-4.4 and PhT: 19.7%+/-4.9), and the PLN had the lowest proportion (15.4%+/-3.1). The opposite relationship was observed with CD62L on na?ve T- helper cells as PP had the lowest proportion (14.2%+/-6.4), the tonsils intermediate (PT: 17.4%+/-2.5 and PhT: 24.3%+/-7.3), and the PLN the highest proportion (45.3%+/-6.5). MAdCAM-1 was highly expressed in the high endothelial venules (HEV) of PP, with variable and weak expression in the tonsils and PLN. PNAd, on the other hand, was highly expressed in HEV of tonsils and PLN, and weakly expressed in the PP. These results indicate that the bovine tonsils share characteristics with both PP and PLN. The alpha4beta7/MadCAM-land CD62L/PNAd interaction may be involved in lymphocyte migration to the tonsils, but it is likely that other adhesion molecules participate as well. Similarities between the human and bovine tonsils suggest that cattle may provide a good model to study the role of the tonsil in the respiratory immune response.     

Ultrastructural and enzyme histochemical aspects of amyloidosis in the bovine renal medulla.

Electron micrsocopic studies of bovine kidneys with amyloidosis showed macrophage-like cells in the interstitial amyloid that were either disseminated or in small groups. They had rather uniform protracted vacuoles filled with parallel fibrils. Similar vacuoles were also found in some reticular interstitial cells. In some samples electron-dense vacuoles and vacuoles containing fibrils were seen. Protracted lysosomal enzyme activity was seen in macrophage-like cells and reticular interstitial cells; these areas of activity showed green birefringence with Congo red. The vacuoles were thought to be lysosomes, and the parallel amyloid fibrils could be a consequence of intracellular formation or of phagocytosis.     

Neurotoxic syndrome of sheep due to the ingestion of plants of the Mediterranean scrub: clinical, histopathological, histochemical and ultrastructural observations

A severe neurological disorder was observed during a very dry season, in sheep pasturing on land with mediterranean vegetation. During the crisis, lasting 5-20", ataxia and convulsions were the main clinical signs. Brain congestion, spongy appearance of the liver, interstitial nephritis and hyperpigmentation of visceral lymph nodes were the most important macroscopic lesions. Histopathological, histochemical and ultrastructural findings confirmed liver and kidney lesions and showed considerable neurovisceral storage of lipofuscin. Although further toxicological and experimental studies are needed to elucidate the origin of the disease, the Authors attribute the outbreak of the neurological syndrome to the ingestion of a neurotoxin containing plant.     

Laboratory model for infectious bovine keratoconjunctivitis: the pathogenicity of different strains of Moraxella bovis, pathology and ultrastructural observations

Further studies were made using C57 mice pretreated with a corticosteroid and inoculated with Moraxella bovis by instillation, as a model for infectious bovine keratoconjunctivitis. Strains of M bovis which had previously been tested in cattle produced a generally similar range of pathogenicity when tested in mice. The pathology in the mouse model closely resembled that in cattle and the value of the model for studies on M bovis was confirmed.     

Further observations on the characteristics of a bovine parainfluenza-3 variant.

Calves were inoculated with a bovine para-influenza-3 variant to determine its pathogenicity and the stability of its cytopathic feature and its inability to agglutinate chicken erythrocytes. The inoculated calves and one contact animal developed an immune response without significant clinical illness. The clinical response in calves was similar to that induced by the parent virus strain. The variant was shown to retain its characteristic cytopathic effect for Madin Darby bovine kidney cells and its property of hemagglutination following one passage in the natural host.     

Lectin histochemical pattern on the normal and cystic ovaries of sows

The lectin histochemical pattern (LHP) was characterized and compared in normal and cystic ovaries of sows. Six biotinylated lectins (PNA, SBA, WGA, RCA‐1, DBA and UEA‐1) were used on tissue sections. In the normal ovaries, the reaction to UEA‐1 and SBA was mild to moderate in mesothelial and endothelial cells. RCA‐1 staining was mild to moderate in theca interna of growing follicles, corpora luteum and mesothelium. In addition, this lectin presented strong reaction in endothelial cells, granulosa cells of atretic follicles, zona pellucida of growing follicles and plasma. DBA showed strong intensity in mesothelial and endothelial cells. There was mild to moderate reactivity to WGA in granulosa cells, corpus luteum and theca interna of follicles in development, and moderate in zona pellucida, in granulosa cells of atretic follicles and mesothelium. PNA staining was mild to moderate in oocytes and in the adventitia and media of medullary arteries. Changes in the LHP of the cystic ovaries were noted; however, there were no differences in these findings between the follicular and luteinized cysts. UEA‐1 reactivity in the cystic ovaries was moderately reduced in the mesothelial and endothelial cells, whereas there was mild reduction in the DBA staining in the granulosa cells. Reaction to RCA‐1 and WGA in the cysts also was decreased in theca interna, zona pellucida and granulosa cells of atretic follicles. Furthermore, endothelium and theca interna in the cystic ovaries presented mild reduction of marcation to SBA, whereas there was decreased reactivity to PNA in the oocytes and adventitia and media layers of the medullary arteries. The results of the current study show that cysts modify the LHP in swine ovaries. These changes of glycoconjugates in many ovarian structures could modify diverse process and may be one of the reasons for decreased fertility in sows.     

Morphological and histochemical observations of the organic components of ostrich eggshell

The organic component of the avian eggshell can be divided into 3 portions, the shell membranes, the matrix and the cuticle. These have been well characterised in the chicken but little has been published with regard to the ostrich (Struthio camelus). A number of recent studies have indicated that the cause of intra-shell embryonic deaths in the ostrich is similar to intra-shell embryonic deaths that occur in the chicken. These deaths in the chicken are associated with the loss of or damage to the waxy cuticle and other organic components of the eggshell, which is reported to be absent in the ostrich eggshell. In this study, preliminary morphological and histochemical analyses, at the level of the light and electron microscope, have characterised the various organic components of the ostrich eggshell. The results of the histochemical and electron microscopical analyses suggest that there may only be 1 shell membrane in this species, which could play a major role in the limitation of bacterial penetration to the embryonic chamber The shell membrane has a distinct elemental profile as determined by EDS analysis. The matrix is shown to decrease in mesh size from the mammillary layer to the vertical crystal layer. The closer packing of the mesh may indicate the presence of a morphologically discernible termination signal to calcification or the remnants of an evolutionary calcified cuticle. The matrix of the pores may also form a defensive barrier against bacterial invasion, which could be damaged as a result of dipping the eggs before incubation.