Polyomavirus-associated Prostatitis in Wistar Han Rats Following Immunosuppression in a Chronic Toxicity Study.

Chronic prostatitis characterized on light microscopic examination by moderate, multifocal, predominantly lymphocytic inflammation associated with epithelial atypia and intranuclear and cytoplasmic inclusion-like material was identified in the prostate gland of 2 Wistar Han rats administered an immunomodulatory test article in a 6-month chronic toxicity study. Transmission electron microscopy of the prostate glands identified 45-nm, nonenveloped, icosahedral virions arranged in paracrystalline array within the cell nuclei in 1 of the 2 rats. The size, shape, location, and array pattern were most consistent with a polyomavirus.

Evaluation of miR-216a and miR-217 as Potential Biomarkers of Acute Exocrine Pancreatic Toxicity in Rats.

Detecting and monitoring exocrine pancreatic damage during nonclinical and clinical testing is challenging because classical biomarkers amylase and lipase have limited sensitivity and specificity. Novel biomarkers for drug-induced pancreatic injury are needed to improve safety assessment and reduce late-stage attrition rates. In a series of studies, miR-216a and miR-217 were evaluated as potential biomarkers of acute exocrine pancreatic toxicity in rats.

The Application of Paraphenylenediamine Staining for Assessment of Phospholipidosis.

Drug-induced phospholipidosis is characterized by intracellular accumulation of phospholipids with lamellar bodies in cells exposed to xenobiotics. Demonstration of the lamellar bodies by transmission electron microscopy (TEM) is the hallmark for a definitive diagnosis of phospholipidosis. However, the preparation of tissue samples for TEM and their ultrastructural evaluation are technically challenging and time consuming.

Neurophysiological assessment of sympathetic cardiovascular activity after loss of postganglionic neurons in the anesthetized rat.

The goal of this study was to determine the degree of sympathetic postganglionic neuronal loss required to impair cardiovascular-related sympathetic activity. To produce neuronal loss separate groups of rats were treated daily with guanethidine for either 5days or 11days, followed by a recovery period. Sympathetic activity was measured by renal sympathetic nerve activity (RSNA).

Characterization of a Novel Intestinal Glycerol-3-phosphate Acyltransferase Pathway and Its Role in Lipid Homeostasis.

Dietary triglycerides (TG) are absorbed by the enterocytes of the small intestine after luminal hydrolysis into monacylglycerol and fatty acids. Before secretion on chylomicrons, these lipids are reesterified into TG, primarily through the monoacylglycerol pathway. However, targeted deletion of the primary murine monoacylglycerol acyltransferase does not quantitatively affect lipid absorption, suggesting the existence of alternative pathways.

Characterization, biomarkers, and reversibility of a monoclonal antibody-induced immune complex disease in cynomolgus monkeys (Macaca fascicularis).

Two 6-month repeat-dose toxicity studies in cynomolgus monkeys illustrated immune complex-mediated adverse findings in individual monkeys and identified parameters that potentially signal the onset of immune complex-mediated reactions following administration of RN6G, a monoclonal antibody (mAb). In the first study, 3 monkeys exhibited nondose-dependent severe clinical signs accompanied by decreased erythrocytes with increased reticulocytes, neutrophilia, monocytosis, thrombocytopenia, coagulopathy, decreased albumin, azotemia, and increased serum levels of activated complement products, prompting unscheduled euthanasia. Histologically, immunohistochemical localization of RN6G was associated with monkey immunoglobulin and complement components in glomeruli and other tissues, attributable to immune complex disease (ICD).

Mechanistic investigations of test article-induced pancreatic toxicity at the endocrine-exocrine interface in the rat.

Pancreatic toxicity commonly affects the endocrine or exocrine pancreas. However, it can also occur at the endocrine-exocrine interface (EEI), where the capillary network of the islet merges with the capillaries of the surrounding acinar tissue, that is, the insulo-acinar portal system. The goal of this article is to describe a novel, test article-induced pancreatic toxicity that originated at the EEI and to summarize investigations into the mechanistic basis of the injury.

Renal pathophysiologic role of cortical tubular inclusion bodies.

Renal tubular inclusion bodies are rarely associated with drug administration. The authors describe the finding of renal cortical tubular intranuclear and intracytoplasmic inclusion bodies associated with the oral administration of a norepinephrine/serotonin reuptake inhibitor (NSRI) test article in Sprague-Dawley (SD) rats. Rats were given an NSRI daily for 4 weeks, and kidney histopathologic, ultrastructural pathology, and immunohistochemical examinations were performed.

Technical guide for nervous system sampling of the cynomolgus monkey for general toxicity studies.

For general toxicity studies, a technique was designed to consistently sample the most important neuroanatomic regions of the brain, spinal cord, and peripheral nerve of cynomolgus monkeys using a limited number of blocks and slides. Using the most rostral portion of the pons as a landmark, the entire fixed brain was cut dorsoventrally into cross-sectional slabs 4 mm in thickness. For microscopic evaluation, six blocks of the brain at the levels of the frontal pole, anterior commissure, rostral thalamus, caudal thalamus, middle cerebellum with brainstem, and occipital lobe were trimmed to fit in standard tissue cassettes.

Ultrastructural localization of extracellular matrix proteins of the lymph node cortex: evidence supporting the reticular network as a pathway for lymphocyte migration.

Background: The lymph node (LN) is a crossroads of blood and lymphatic vessels allowing circulating lymphocytes to efficiently recognize foreign molecules displayed on antigen presenting cells. Increasing evidence indicates that after crossing high endothelial venules, lymphocytes migrate within the node along the reticular network (RN), a scaffold of fibers enwrapped by fibroblastic reticular cells (FRC). Light microscopy has shown that the RN contains specific extracellular matrix (ECM) proteins, which are putative molecular "footholds" for migration, and are known ligands for lymphocyte integrin adhesion receptors.

Cardiovascular effects in rats following exposure to a receptor tyrosine kinase inhibitor.

The receptor tyrosine kinase receptor (RTK) signaling pathway, mesenchymal-epithelial transition factor (c-Met)/hepatocyte growth factor receptor (HGFR), has been implicated in oncogenesis and is a target of interest in cancer therapy. PF-04254644 is a potent and selective inhibitor of c-Met/HGFR. Wide ligand binding profiling of PF-04254644 revealed a potentially significant interaction with phosphodiesterase (PDE) 3, and follow-up PDE enzyme activity assays confirmed PF-04254644 as a potent inhibitor of PDE3 as well as other PDEs (1, 2, 5, 10, and 11).

Human skin in organ culture and human skin cells (keratinocytes and fibroblasts) in monolayer culture for assessment of chemically induced skin damage.

Human skin cells (epidermal keratinocytes and dermal fibroblasts) in monolayer culture and human skin in organ culture were exposed to agents that are known to produce irritation (redness, dryness, edema and scaly crusts) when applied topically to skin. Among the agents used were three well accepted contact irritants (i.e.

Porcine brain microvessel endothelial cells as an in vitro model to predict in vivo blood-brain barrier permeability.

The objective of the study was to establish primary cultured porcine brain microvessel endothelial cells (PBMECs) as an in vitro model to predict the blood-brain barrier (BBB) permeability in vivo. The intercellular tight junction formation of PBMECs was examined by electron microscopy and measured by transendothelial electrical resistance (TEER). The mRNA expression of several BBB transporters in PBMECs was determined by reverse transcriptionpolymerase chain reaction analysis.

Modeling inflammation-drug interactions in vitro: a rat Kupffer cell-hepatocyte coculture system.

Xenobiotic-inflammation interactions lead to hepatotoxicity in vivo. Selected xenobiotic agents (acetaminophen, APAP; chlorpromazine, CPZ; allyl alcohol, AlOH; monocrotaline, MCT) for which this occurs were evaluated for ability to elicit the release of Kupffer cell (KC)-derived inflammatory mediators and to modulate lipopolysaccharide (LPS)-stimulated release of these mediators. Using KCs and hepatocytes (HPCs) isolated from rat, KC/HPC cocultures were treated with either LPS, xenobiotic, vehicle or a combination.

Comparative methods for multiplex analysis of cytokine protein expression in plasma of lipopolysaccharide-treated mice.

Changes in circulating cytokines might serve as predictors of compound-evoked inflammatory responses. CD-1 mice were treated with lipopolysaccharide (LPS; 0.2 ml of 0.

A stepwise method for the isolation of endothelial cells and smooth muscle cells from individual canine coronary arteries.

Methods for the stepwise isolation of endothelial cells and smooth muscle cells from individual canine coronary arteries are described. Both cell types can be isolated in pure culture with high yields. Dogs are a common species used in the study of atherosclerosis and coronary artery disease.

Cytoskeletal protein degradation and neurodegeneration evolves differently in males and females following experimental head injury.

The resulting neuropathological degeneration that occurs following a traumatic brain injury (TBI) is a consequence of both immediate and secondary neurochemical sequelae. Proteolysis of cytoskeletal proteins, triggered by calcium-mediated events, is believed to be a particularly significant contributor to TBI-induced neuronal death. To date, efforts to associate cytoskeletal degradation and neurodegeneration in TBI have been primarily qualitative or semiquantitative.

Systemic proliferative changes and clinical signs in cynomolgus monkeys administered a recombinant derivative of human epidermal growth factor.

Epidermal growth factor (EGF) effects have been explored extensively in vivo in rodents, but little is known about trophic responses in nonhuman primates. A previous publication reports the hyperplastic epithelial/parenchymal changes noted in the digestive tract (tongue, esophagus, stomach, intestine, liver, gallbladder, pancreas, and salivary glands) of adult cynomolgus monkeys treated with recombinant human EGF(1-48) (rhEGF(1-48)). This report documents clinical findings and structural effects in the remaining epithelium-containing tissues of these animals.

Spontaneously occurring hepatocellular neoplasia in adolescent cynomolgus monkeys (Macaca fascicularis).

Spontaneous hepatic neoplasms were identified in two adolescent (<5 years of age) male cynomolgus monkeys (Macaca fascicularis). Monkey No. 1 had a solitary hepatocellular carcinoma (HCC).

Malignant intracranial teratoma in a juvenile Wistar rat.

An intracranial malignant teratoma was identified in a 91-day-old male Wistar rat manifesting central nervous system-related clinical signs. This tumor occupied the right midbrain and portions of the right caudal cerebrum and cranioventral cerebellum. Microscopically, the tumor contained intermingled cartilage, bone (with medullary hematopoietic tissue), fibrous connective tissue, skeletal muscle, fat, pseudostratified ciliated epithelium, stratified squamous epithelium, serous and mucoserous glands, and neural tissue with ependymal and choroid plexus epithelia.

Transport properties are not altered across Caco-2 cells with heightened TEER despite underlying physiological and ultrastructural changes.

Selected properties of Caco-2 cells were examined after disparate transepithelial electrical resistance (TEER) measurements were observed in two populations of Caco-2 cells. Comparisons were made between the early passages of Caco-2 cells (Caco-2E, passages 35-47) and the later passages of cells (Caco-2L, passages 87-112). Transmission electron microscopy revealed that regions of Caco-2L cells were composed of multiple cell layers rather than the monolayers observed in Caco-2E cells.

Elemental studies in rat lens during galactose cataract reversal.

Alterations in elemental composition of the normal lens have been reported to accompany galactose cataract development in rats. In this report we present the changes in regional distribution of Na, K, Cl, P, S and Ca during the reversal of galactose-induced cataracts. Elemental X-ray maps of lenses from young female Sprague Dawley rats fed 50% galactose for 20 days were examined at 0, 20, 40 and 90 days following the transfer of galactose fed rats to Purina Rat Chow diet.

Subacute toxicity of a novel inhibitor of acyl-CoA: cholesterol acyltransferase in beagle dogs.

PD 132301-2 is a substituted urea hypolipidemic and antiatherosclerotic agent that is a potent inhibitor of acyl-CoA:cholesterol acyltransferase (ACAT). To determine its subacute toxicity, PD 132301-2 was administered orally to beagle dogs at 0, 6, 12, 25, 50, 200, 400, or 800 mg/kg/day for 2 weeks. Clinico-pathologic evaluations were completed on all dogs.