Global VetPathology

Veterinary pathologists are key contributors to multidisciplinary biomedical research. However, they are occasionally excluded from authorship in published articles despite their substantial intellectual and data contributions. To better understand the potential origins and implications of this practice, we identified and analyzed 29 scientific publications where the contributing pathologist was excluded as an author. The amount of pathologist-generated data contributions were similar to the calculated average contributions for authors, suggesting that the amount of data contributed by the pathologist was not a valid factor for their exclusion from authorship. We then studied publications with pathologist-generated contributions to compare the effects of inclusion or exclusion of the pathologist as an author. Exclusion of the pathologist from authorship was associated with significantly lower markers of rigor and reproducibility compared to articles in which the pathologist was included as author. Although this study did not find justification for the exclusion of pathologists from authorship, potential consequences of their exclusion on data quality were readily detectable.

Naked mole-rats (NMRs) are common in the managed care of zoos and valuable models for aging research. Limited information on NMR neuropathology is available despite many studies regarding their aging physiology. Histologic sections of brain from 27 adult (5-27 years old) NMRs from 2 zoos were reviewed to determine presence or absence of lesions associated with advanced age in humans and other mammals. A majority (23/27; 85%) of NMR brains had cerebral cortical neuronal changes with rounded or angular neurons, cytoplasmic vacuoles containing pale yellow pigment, periodic acid-Schiff (PAS)-positive granules and green autofluorescence, compatible with lipofuscinosis. Less severe lesions were present in cerebellar Purkinje cells, medulla, and hippocampal neurons. The hypothalamic neuropil of all NMRs had scattered variably sized PAS-positive granules and 10 (37%) had larger round bodies consistent with corpora amylacea. The youngest NMRs, 5 to 7 years old, generally had minimal or no cerebrocortical lesions. Further studies will help understand brain aging in this long-lived species.

JOHN P. SUNDBERG, HARM HOGENESCH, ALEXANDER YU. NIKITIN, PIPER M. TREUTING, AND JERROLD M. WARD The Jackson Laboratory, Bar Harbor, Maine, USA Purdue University College of Veterinary Medicine, West Lafayette, Indiana, USA Cornell University College of Veterinary Medicine, Ithaca, New York, USA University of Washington, Seattle, Washington, USA Global VetPathology, Montgomery Village, Maryland, USA

CD4 and CD8 are glycoproteins found on the surface of T lymphocytes and other immune cells. Researchers have long been able to detect these T cell subset markers in formalin‐fixed, paraffin‐embedded human tissues. CD4+ and CD8+ T lymphocyte levels and distribution are commonly used to determine disease state, for example in HIV infections. To date, reliable and consistent identification of these markers by immunohistochemistry (IHC) in fixed, paraffin‐embedded mouse tissues has been difficult. Typically, researchers must rely on frozen mouse tissues in order to detect these T cell subset markers in mice. However, not all facilities can support frozen IHC work. In contrast, formalin‐fixed, paraffin‐embedded (FFPE) is the standard archival tissue format. Therefore, we focused on developing reliable CD4 and CD8 IHC for mouse tissues fixed in formalin or Histochoice (Sigma‐Aldrich; St. Louis, MO), an alcohol‐based fixative.Normal mouse spleen was selected as the target tissue because it is a tissue in which a standard pattern for CD4 + and CD8 + T cell distribution would be recognizable. We used Anti‐Mouse CD8a Purified [4SM15] and Anti‐Mouse CD4 [4SM95] (eBiosciences; San Diego, CA) for which some prior success in IHC on FFPE had been reported by co‐author Rehg. For the FFPE tissues, we tried different heat antigen retrieval (AR) methods including citrate, TRIS and EDTA based buffers at multiple pHs. Because alcohol‐based fixatives do not induce the aldehyde cross‐linking and consequent epitope masking encountered with formalin fixation, AR was omitted for Histochoice‐fixed, paraffin‐embedded (HCPE) tissues. Multiple detection approaches were tried, including avidin‐biotin complex with horseradish peroxidase (ABC HRP) and polymer based detection.In FFPE tissues, high (8.0) pH EDTA heat antigen retrieval provided the best results, which is not unexpected given that CD4 and CD8 are membranous markers. For CD4, the optimal primary []s were 1.6mg/ml for FFPE spleen and 12.5 mg/ml for HCPE. For CD8, the optimal primary concentration was 5 mg/ml in both the FFPE and HCPE spleen. Use of a secondary antibody, Biotin‐SP‐conjugated AffiniPure Donkey Anti‐rat IgG (Jackson ImmunoResearch; West Grove, PA) with an ABC HRP detection approach worked best for both FFPE and HCPE CD8 labeling as well as for the FFPE CD4 labeling. In contrast, the best detection system for the HCPE CD4 IHC was a polymer based detection approach, specifically ImmPRESS Anti‐rat IgG (Peroxidase) Polymer Detection Kit (Vector Labs; Burlingame, CA). These combinations provided the least background while still enabling easy visualization of the markers in the appropriate biological pattern. This work is being expanded to other mouse tissues including the lung where it will be used to examine changes in CD4 and CD8 T cell subsets in infectious disease studies.Support or Funding InformationThis research has been funded by Dr. Davis' startup funds from the Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University and the Intramural Research Program of the NIH Clinical Center (ZIA CL000037‐27, ZIA CL000146‐21, and ZIA CL000192‐17).

Pathology is a discipline of medicine that adds great benefit to aging studies of rodents by integrating in vivo, biochemical, and molecular data. It is not possible to diagnose systemic illness, comorbidities, and proximate causes of death in aging studies without the morphologic context provided by histopathology. To date, many rodent aging studies do not utilize end points supported by systematic necropsy and histopathology, which leaves studies incomplete, contradictory, and difficult to interpret. As in traditional toxicity studies, if the effect of a drug, dietary treatment, or altered gene expression on aging is to be studied, systematic pathology analysis must be included to determine the causes of age-related illness, moribundity, and death. In this Commentary, the authors discuss the factors that should be considered in the design of aging studies in mice, with the inclusion of robust pathology practices modified after those developed by toxicologic and discovery research pathologists. Investigators in the field of aging must consider the use of histopathology in their rodent aging studies in this era of integrative and preclinical geriatric science (geroscience).

Burkholderia mallei and Burkholderia pseudomallei are potentially lethal pathogens categorized as biothreat agents due, in part, to their ability to be disseminated via aerosol. There are no protective vaccines against these pathogens and treatment options are limited and cumbersome. Since disease severity is greatest when these agents are inhaled, efforts to develop pre- or post-exposure prophylaxis focus largely on inhalation models of infection. Here, we demonstrate a non-invasive and technically simple method for affecting the inhalational challenge of BALB/c mice with B. pseudomallei and B. mallei. In this model, two investigators utilized common laboratory tools such as forceps and a micropipette to conduct and characterize an effective and reproducible inhalational challenge of BALB/c mice with B. mallei and B. pseudomallei. Challenge by oropharyngeal aspiration resulted in acute disease. Additionally, 50% endpoints for B. pseudomallei K96243 and B. mallei ATCC 23344 were nearly identical to published aerosol challenge methods. Furthermore, the pathogens disseminated to all major organs typically targeted by these agents where they proliferated. The pro-inflammatory cytokine production in the proximal and peripheral fluids demonstrated a rapid and robust immune response comparable to previously described murine and human studies. These observations demonstrate that OA is a viable alternative to aerosol exposure.

Evidence from studies in animals is essential for identifying chemicals likely to cause or contribute to many diseases in humans, including cancers. Yet, to avoid or delay the implementation of protective public health standards, the chemical industry typically denies cancer causation by agents they produce. The spurious arguments put forward to discount human relevance are often based on inadequately tested hypotheses or modes of action that fail to meet Bradford Hill criteria for causation. We term the industry attacks on the relevance of animal cancer findings as the "War on Carcinogens." Unfortunately, this tactic has been effective in preventing timely and appropriate health protective actions on many economically important yet carcinogenic chemicals, including: arsenic, asbestos, benzene, 1,3-butadiene, formaldehyde, methylene chloride, phthalates, tobacco usage, trichloroethylene [TCE], and others. Recent examples of the "War on Carcinogens" are chemicals causing kidney cancer in animals. Industry consultants argue that kidney tumor findings in rats with exacerbated chronic progressive nephropathy (CPN) are not relevant to humans exposed to these chemicals. We dispute and dismiss this unsubstantiated claim with data and facts, and divulge unprofessional actions from a leading toxicology journal.

ObjectiveComparison of characteristics of fire with non-fire households to determine factors differentially associated with fire households (fire risk factors).Design, setting and subjectsNational household telephone survey in 2004–2005 by the US Consumer Product Safety Commission with 916 fire households and a comparison sample of 2161 non-fire households. There were an estimated 7.4 million fires (96.6% not reported to fire departments) with 130 000 injuries.Main outcome measureBivariate analysis and multivariate logistic regression analyses to assess differences in household characteristics.ResultsSignificant factors associated with fire households were renting vs. owning (OR 1.988 p<0.0001); household members under 18 year of age (OR 1.277 p<0.0001); lack of residents over 64 years old (OR 0.552 p=0.0007); and college or higher education (some college OR 1.444 p=0.0360, college graduate OR 1.873, p<0.0001, postgraduate OR 2.156 p<0.0001). Not significant were age of house; race; ethnicity; and income. Number of smokers was borderline significant (OR 1.132 p=0.1019) but was significant in the subset of fire households with non-cooking fires (OR 1.383 p=0.0011). Single family houses were associated with non-fire households in the bivariate analysis but not in the multivariate analyses.ConclusionRenting, household members under 18 years old and smokers are risk factors for unattended fires, similar to the literature for fatal and injury fires. Differences included household members over 65 years old (associated with non-fire households), college/postgraduate education (associated with fire households) and lack of significance of income. Preventing cooking fires (64% of survey incidents), smoking prevention efforts and fire prevention education for families with young children have the potential for reducing unattended fires and injuries.