Analysis of mouse model pathology: a primer for studying the anatomic pathology of genetically engineered mice.

This primer of pathology is intended to introduce investigators to the structure (morphology) of cancer with an emphasis on genetically engineered mouse (GEM) models (GEMMs). We emphasize the necessity of using the entire biological context for the interpretation of anatomic pathology. Because the primary investigator is responsible for almost all of the information and procedures leading up to microscopic examination, they should also be responsible for documentation of experiments so that the microscopic interpretation can be rendered in context of the biology.

Manual immunohistochemistry staining of mouse tissues using the avidin-biotin complex (ABC) technique.

There are many variations on the immunohistochemistry (IHC) procedure, but all are based on attachment of a primary antibody to a unique epitope on or within the cell. This step is followed by incubation of the cell/primary antibody complex with another, secondary antibody that recognizes the species in which the primary antibody was produced. The secondary antibody has an indicator molecule attached to it.

Manual hematoxylin and eosin staining of mouse tissue sections.

The hematoxylin and eosin (H&E) stain is the standard used for microscopic examination of tissues that have been fixed, processed, embedded, and sectioned. It can be performed manually or by automation. For economic reasons, the manual technique is generally the method of choice for facilities with a low sample volume.

Mouse tissue fixation.

One of the primary goals of fixation is to stop postmortem changes that degrade the tissue and allow optimal preservation of morphologic and cytological detail as well as nucleic acid integrity. Following death, tissues soon undergo autolysis, and if organisms from the gastrointestinal, urinary, or respiratory tracts are present, their colonization can soon cause putrefaction. Time is of the essence because warmer temperatures accelerate both types of degradation.

Limited mouse necropsy.

Procurement of mouse tissues or organs is essential for complete verification of almost any phenotype. A proper necropsy can yield information that is difficult to obtain by limited biopsy or surgical intervention. The protocol described here is for a limited autopsy involving the thorax and abdomen only, and does not include all organs.

Structured reporting in anatomic pathology for coclinical trials: the caELMIR model.

Electronic media, with their tremendous potential for storing, retrieving, and integrating data, are an essential part of modern collaborative multidisciplinary science. Structured reporting is a fundamental aspect of keeping accurate, searchable electronic records. This discussion on structured reporting in anatomic pathology for pre- and coclinical trials in animal models provides background information for scientists who are not familiar with structured reporting.

Quantitation of fixative-induced morphologic and antigenic variation in mouse and human breast cancers.

Quantitative Image Analysis (QIA) of digitized whole slide images for morphometric parameters and immunohistochemistry of breast cancer antigens was used to evaluate the technical reproducibility, biological variability, and intratumoral heterogeneity in three transplantable mouse mammary tumor models of human breast cancer. The relative preservation of structure and immunogenicity of the three mouse models and three human breast cancers was also compared when fixed with representatives of four distinct classes of fixatives. The three mouse mammary tumor cell models were an ER+/PR+ model (SSM2), a Her2+ model (NDL), and a triple negative model (MET1).

Phosphatase and tensin homologue deleted on chromosome 10 deficiency accelerates tumor induction in a mouse model of ErbB-2 mammary tumorigenesis.

Loss of the tumor suppressor phosphatase and tensin homologue deleted on chromosome 10 (PTEN) and amplification or elevated expression of ErbB-2 are both involved in human breast cancer. To directly test the importance of these genetic events in mammary tumorigenesis, we have assessed whether mammary-specific disruption of PTEN could cooperate with activation of ErbB-2. Transgenic mice expressing ErbB-2 under the transcriptional control of its endogenous promoter (ErbB-2(KI)) were interbred with mice carrying conditional PTEN alleles and an MMTV/Cre transgene.

Protective immunity to SIV challenge elicited by vaccination of macaques with multigenic DNA vaccines producing virus-like particles.

We utilized SIV(mne) infection of Macaca fascicularis to assess the efficacy of DNA vaccination alone, and as a priming agent in combination with subunit protein boosts. All SIV(mne) structural and regulatory genes were expressed using the human cytomegalovirus Immediate Early-1 promoter in plasmids that directed the formation of virus-like particles in vitro. Macaques (n = 4) were immunized intradermally and intramuscularly four times over 36 weeks with 3 mg plasmid DNA.

Molecular analysis of metastasis in a polyomavirus middle T mouse model: the role of osteopontin.

Introduction: In order to study metastatic disease, we employed the use of two related polyomavirus middle T transgenic mouse tumor transplant models of mammary carcinoma (termed Met and Db) that display significant differences in metastatic potential.

Methods: Through suppression subtractive hybridization coupled to the microarray, we found osteopontin (OPN) to be a highly expressed gene in the tumors of the metastatic mouse model, and a lowly expressed gene in the tumors of the lowly metastatic mouse model. We further analyzed the role of OPN in this model by examining sense and antisense constructs using in vitro and in vivo methods.

Disseminated microsporidiosis in a pancreas/kidney transplant recipient.

Human microsporidiosis has been described most commonly in patients with acquired immunodeficiency syndrome and only rarely in those with other forms of immunosuppression. Only 11 cases of microsporidiosis have been reported previously in solid transplant recipients. To our knowledge, this is the first report to describe a case of microsporidiosis in a pancreas/kidney transplant recipient in whom multi-organ system dissemination was observed.

Follicular lipidosis in three Rottweilers.

Abstract  Follicular lipidosis is reported in three young Rottweilers that developed hypotrichosis of the mahogany-coloured points of the face and feet. One dog had concurrent lightening and dulling of the remaining hair. Hair matrix cells were swollen with intracellular lipid, identified by electron microscopy and oil-red-O staining.