Abstract
Endoscopic biopsies from the gastrointestinal tract are frequently encountered by the diagnostic pathologist. These biopsies often present an array of diagnostic challenges, one of which is the lack of standard morphologic and diagnostic criteria for evaluating inflammatory conditions. Recently the World Small Animal Veterinary Association Gastrointestinal Standardization Group completed a monograph depicting the major histopathological changes seen in inflammation of the gastric body, gastric antrum, duodenum and colon of dogs and cats. For each anatomical region there is a series of high quality photomicrographs showing examples of normal histology along with mild, moderate and marked inflammation. Where applicable, criteria for the number and type of cellular infiltrates are provided. The authors also designed histopathological reporting forms to encourage systematic evaluation and reporting. This monograph is a “must have” for diagnostic pathologists evaluating endoscopic biopsies.
Day MJ, Bilzer T, Mansell J, et al. Histopathological standards for the diagnosis of gastrointestinal inflammation in endoscopic biopsy samples from the dog and cat: A report from the World Small Animal Veterinary Association Gastrointestinal Standardization Group. J Comp Pathol
Certain strains of mice, including C3H/He, are known to be susceptible to dystrophic cardiac calcification (DCC). DCC results in calcium phosphate deposits in the myocardial tissue of affected mice. Recently the ATP binding cassette C 6 gene (Abcc6) was determined to be responsible for DCC, but the mechanism by which the gene product leads to dystrophic calcification was not known. Here the authors compared DCC-susceptible C3H/He mice with DCC-resistant C57BL/6 mice and discovered a missense mutation in Abcc6 that creates an additional donor splice site in C3H/He mice. This mutation results in premature termination of the protein and subsequent deficiency of functional protein in susceptible mice. Identical mutations were found in DBA/2J and 129S1/SvJ strains, both of which are susceptible to DCC.
Aherrahrou Z, Doehring LC, Ehlers EM, et al. An alternative splice variant in Abcc6, the gene causing dystrophic calcification, leads to protein deficiency in C3H/He Mice. J Biol Chem
Pulmonary fibrosis can be fatal in humans, and thus animal models are used to study the pathogenesis of this condition and determine the efficacy of therapeutics. Bleomycin-induced pulmonary fibrosis is the most common model used; however, reliance on histopathologic analysis of fibrotic lung tissue is not without problems. In addition to intra-observer variation, the fibrotic tissue is often unevenly distributed throughout the pulmonary parenchyma. Some pathologists use the Ashcroft scale to assign a grade from 0 to 8. Drawbacks of this scale include a lack of definitions for grades 2, 4 and 6, and incomplete validation in animal models. Here the authors present a modified Ashcroft scale with complete descriptions for all grades, and used this to validate histologic evaluation in rats treated with bleomycin. Use of the modified scale was associated with less inter- and intra-observer variability than the original unmodified scale. The modified scale also correlated better with lung density assessed by CT scan. Further evaluation of the modified Ashcroft scale in animals is warranted.
Hubner RH, Gitter W, El Mokhtari NE, et al. Standardized quantification of pulmonary fibrosis in histological samples. Biotechniques
The presence of lipogranulomas in canine livers is not uncommon, but a detailed comparison of lipogranulomas in livers with and without portosystemic shunts (PSS) has not been performed. Here the authors examined liver biopsies of 65 dogs with PSS and 79 dogs without PSS. Lipogranulomas were present in 55.4% of dogs with PSS and 46.8% of dogs without PSS. However, when the analysis was restricted to dogs greater than one year of age there were significantly more lipogranulomas in the PSS group than the non-PSS group (33/41, 80.5% versus 37/77, 48.1%, respectively). The lipogranulomas were randomly distributed within the hepatic lobule in PSS cases. Biopsies with PSS also showed a greater density of lipogranulomas per unit area. The authors divided the lipogranulomas into three groups based on the number of vacuoles and amount of pigment. Pigment granules were positive for Berlin blue, PAS, Sudan black B and macrophage scavenger receptor class A, and negative for Hall's, albumin and hepatocyte antigen, indicating that the pigment consists of ceroid and hemosiderin.
Isobe K, Matsunaga S, Nakayama H, Uetsuka K. Histopathological characteristics of hepatic lipogranulomas with portosystemic shunt in dogs. J Vet Med Sci
More and more pathologists are performing in situ hybridization and/or immunohistochemistry to facilitate localization of gene expression. Deutsch and colleagues have outlined the minimum information specifications for in situ hybridization and immunohistochemistry experiments (MISFISHIE). The criteria are modeled after the Minimum Information About a Microarray Experiment (MIAME) which has been well received by the research community. The goal is to have enough relevant information that another investigator could validate the findings. These guidelines define what information should be reported, but is it up to the investigator to decide how it is reported. Specific categories of information include experimental design, biomaterials (specimens) and treatments (section or whole-mount preparation), reporters (probes or antibody) information, staining protocols and parameters, imaging data and parameters, and image characteristics. The authors reviewed current publications to determine if they would have been compliant with MISFISHIE guidelines, and found that most would require only modest additions to achieve compliance. More information on MISFISHIE guidelines and the complete checklist can be found online at http:www.mged.org/Workgroups/MISFISHIE.
Deutsch EW, Ball CA, Berman JJ, et al. Minimum information specification for in situ hybridization and immunohistochemistry experiments (MISFISHIE). Nat Biotechnol