Renal Interstitial Lipid Accumulation in Cats with Chronic Kidney Disease.

Chronic kidney disease (CKD) is a common progressive condition described in dogs and cats, involving several non-specific morphological and histological lesions. Recently, renal interstitial lipid accumulation was reported in cats with CKD; however, to date, little is known about this condition and its pathogenesis. The aim of this study was to investigate the occurrence and to characterize renal interstitial lipid deposits in dogs and cats. A total of 49 animals (27 cats and 22 dogs) with CKD were included in the study. Interstitial lipid accumulation was found exclusively in cats, affecting both males and females. In 55.6% of the cases, the extent of the lesion was not equally distributed in right and left kidneys. The lesion was always found in the cortical region, associated with an inflammatory reaction. Lipid macrovacuoles were also observed in the tubular epithelium, as well as in areas of tubulorrhexis. The amount of lipid deposited was variable, being more extensive in older animals. Data from this study suggest that interstitial lipid accumulation may be related to tubular lipidosis (typical of feline kidneys) associated with epithelial degeneration and lysis, and to tubular basement membrane fragmentation. Extended studies on this condition are necessary, as it appears to be involved in the progression of CKD and may, therefore, have repercussion in the clinical management of the disease and in the development of new approaches to delay its advance.

Cytological, immunocytochemical, ultrastructural and growth characterization of the rainbow trout liver cell line RTL-W1.

Despite its wide use in toxicology, a detailed characterization of RTL-W1 cell line lagged behind leaving ambiguities about its cell origin. We aimed to better characterize the line regarding cell phenotype and tumorigenic state. We studied RTL-W1 cells in monolayers and in (4-22-week-old) aggregates considering: (a) morphology (light and electron microscopy); (b) immunophenotype using AE1/AE3, vimentin, Cam5.2, CK7 and CK19 and e-cadherin antibodies and (c) growth behavior. RTL-W1 organelle content is constituted basically by mitochondria and abundant free ribosomes, with no (cytochemically) detectable peroxisomes and lysosomes. Immunocytochemistry showed a strong marking for AE1/AE3 and vimentin (in a cell subset). Since AE1/AE3 stained biliary epithelial ducts in trout liver, and considering the morphological characteristics and long term culture, RTL-W1 cells seem more similar to bile preductular epithelial cells (considered as stem cells in teleost liver). Also, we observed abnormal nuclear features described for both malignant cell lines and stem cells, so we could not conclude about tumorigenicity. Cell aggregates had signs of hepatocytic differentiation, such as the development of RER and microvillus-like projections into intercellular spaces. The morphological resemblance to the original tissue suggests that aggregates could have an added value in metabolic as well as in cell-to-cell interaction studies.

Crystalline inclusions in hepatocytes and associated interhepatocytic macrophages from female Ohrid trout (Salmo letnica Kar.).

When characterizing the liver ultrastructure in Ohrid trout, we noticed that cells often displayed unusual cytoplasmic crystalline inclusions. Their morphology varied much, concerning the size, shape and electron density, showing aspects never reported in fish liver. In hepatocytes, the inclusions existed in close topographical relationship with dense bodies (often within them). Such "crystals" inclusions also existed in macrophages and in biliary passages lumina. Data revealed seasonal/breeding-related changes of the dense bodies and crystalline inclusions within hepatocytes; decreasing from the earliest to the more advanced ovary maturation stages. Additionally, based on the negative correlations between the amounts of dense bodies and of "crystals" and the ovary somatic ratio, we suggested there might be connections between the sex steroids status and the inclusions formation. A positive correlation between the quantities of "crystals" and of dense bodies further suggested that the inclusions might derive from normal processes, e.g., the females' cyclic liver changes, that involves dense bodies' turnover. However, a toxicological aetiology cannot be excluded. Additionally, multiple mechanisms can contribute to the "crystals" genesis. Facing literature reports and because the inclusions content seemed washed out during tissue processing, they are likely lipid in nature, but their exact composition and genesis require further analyses.

Use of destained cytology slides for the application of routine special stains.

BACKGROUND: Special stains to demonstrate microorganisms or intra- and extracellular substances have not been evaluated in detail regarding their applicability and usefulness in destained cytologic specimens. OBJECTIVES: The aim of this study is to compare the results of routine special stains on destained slides previously stained with Hemacolor and on fresh (unstained) specimens. METHODS: Archival Hemacolor-stained fine needle aspirate specimens of inflammation with infectious agents (bacterial, mycobacterial, and fungal infections), neoplasia (melanoma, myxosarcoma, and mammary adenocarcinoma), and hemorrhage (pericardial effusion) from 14 dogs and 7 cats were selected. Cells in a minimum of 4 fields were photographed and 5 slides from each case were then destained by different methods (alcohol acid or microwave). Seven special stains were applied selectively to the destained slides, depending on the cytologic findings: periodic acid Schiff, Grocott-Gomori methenamine silver, Gram's, Ziehl-Neelsen, Alcian blue, Fontana-Masson, and Prussian blue. The same fields were rephotographed and 2 observers evaluated the slides qualitatively, with comparison to fresh cytologic specimens from similar lesions. RESULTS: Special stains applied to destained slides demonstrated the expected cellular and extracellular material or organisms independent of the destaining method. Staining intensity, nonspecific staining (background), cell morphology, and nuclear counterstaining results were similar to those of special stains applied to fresh unstained slides. CONCLUSIONS: Destaining does not appear to affect the results of routine special staining for cytologic specimens. Destaining before special stains may be a valuable diagnostic strategy when few slides are present or only stained slides are available.