Points to consider regarding the use and implementation of virtual controls in nonclinical general toxicology studies.

The replacement of a proportion of concurrent controls by virtual controls in nonclinical safety studies has gained traction over the last few years. This is supported by foundational work, encouraged by regulators, and aligned with societal expectations regarding the use of animals in research. This paper provides an overview of the points to consider for any institution on the verge of implementing this concept, with emphasis given on database creation, risks, and discipline-specific perspectives.

International Harmonization of Nomenclature and Diagnostic Criteria (INHAND): Non-proliferative and Proliferative Lesions of the Non-human Primate (M. fascicularis).

The INHAND (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions Project (www.toxpath.org/inhand.asp) is a joint initiative of the Societies of Toxicologic Pathology from Europe (ESTP), Great Britain (BSTP), Japan (JSTP) and North America (STP) to develop an internationally accepted nomenclature for proliferative and nonproliferative lesions in laboratory animals. The purpose of this publication is to provide a standardized nomenclature for classifying microscopic lesions observed in most tissues and organs from the nonhuman primate used in nonclinical safety studies. Some of the lesions are illustrated by color photomicrographs. The standardized nomenclature presented in this document is also available electronically on the internet (http://www.goreni.org/). Sources of material included histopathology databases from government, academia, and industrial laboratories throughout the world. Content includes spontaneous lesions as well as lesions induced by exposure to test materials. Relevant infectious and parasitic lesions are included as well. A widely accepted and utilized international harmonization of nomenclature for lesions in laboratory animals will provide a common language among regulatory and scientific research organizations in different countries and increase and enrich international exchanges of information among toxicologists and pathologists.

Fatal atypical O:3 Yersinia pseudotuberculosis infection in cynomolgus macaques.

Fatal Yersinia pseudotuberculosis infection in cynomolgus macaques was diagnosed based upon pathology, microbiology and PCR for this study. Pathological findings included acute, erosive to ulcerative, necrohemorrhagic enterocolitis. Genotyping by PCR showed an O:3 pattern (gmd-fcl(+), ddhC-prt(+), manB(+), ddhA-B(+)), but an additional gene, wbyK, was detected. This is the second report to identify wbyK+ O:3 genotype as the cause of fatal yersiniosis. The first case was reported in 2008, and involved farm deer in the U.S. As the frequency of wbyK+ O:3 genotype is found more often in different carriers, O:3 genotype is proposed to be divided into two subtypes: O:3a without wbyK and O:3b with wbyK. Virulence gene analysis showed the presence of inv, ypmC, irp1, ybtP-ybtQ, yadA, yopB, yopH, lcrF, and suggested that this O:3b isolate could be a highly pathogenic strain to cynomolgus macaques.

Spontaneous aortic dissecting hematoma in two dogs.

This report describes 2 cases of spontaneous aortic dissecting hematoma in young Border Collie and Border Collie crossbred dogs. Histology was performed in one of the cases involving an unusual splitting of the elastin present within the wall of the aorta, consistent with elastin dysplasia as described in Marfan syndrome in humans. The first case involved a young purebred Border Collie that died suddenly and the second case involved a Border Collie crossbred dog that died after a 1-month history of seizures. Gross lesions included pericardial tamponade with dissection of the ascending aorta in the former case and thoracic cavity hemorrhage, mediastinal hematoma, and aortic dissection in the latter. Histologic lesions in the case of the Border Collie crossbred dog included a dissecting hematoma of the ascending aorta with elastin dysplasia and right axillary arterial intimal proliferation.