Toxicologic Pathology Forum: Opinion on Performing Good Laboratory Practice Histopathology Evaluation for Nonclinical Toxicity Studies in a Remote Location.

Toxicologic/veterinary pathologists are working remotely from Good Laboratory Practice (GLP) test facilities (TFs) in increasing numbers, most commonly in home-office settings. A study pathologist (SP) generating data on GLP-compliant nonclinical studies must be keenly aware of applicable national GLP regulations and comply with TF and protocol requirements. This Toxicological Pathology Forum Opinion Piece will summarize primary areas of emphasis for the SP generating GLP data using glass slides. Peer review and digital review of whole slide images are out of scope for this opinion piece. Key GLP considerations for primary pathology on glass slides are discussed with respect to SP location and employment status, including pathologist qualifications, specimen management, facilities, equipment, archive, and quality assurance. Notable differences between national GLP regulations of the United States, the United Kingdom, Germany, the Netherlands, France, Ireland, Switzerland, Italy, and Israel are presented. With the understanding that each combination of location and employment is unique, the authors provide a general overview of considerations for successful remote GLP work.

Opinion on Maintaining In-House GLP Status for Toxicologic Pathology in Pharmaceutical and (Agro)Chemical Development.

Many pharmaceutical companies have recently elected to stop maintaining good laboratory practices (GLP) status of their R&D sites. Similar discussions have also been engaged in the (agro)chemical industry. This opinion paper examines the pros and cons of maintaining facility GLP status for the purposes of performing the pathology interpretation or peer reviews of GLP studies internally. The toxicologic pathologist provides gross and histomorphologic evaluation and interpretation of nonclinical exploratory and regulatory studies during drug and (agro)chemical development. This assessment significantly contributes to human risk assessment by characterizing the toxicological profile and discussing the human relevance of the findings. The toxicologic pathologist is a key contributor to compound development decisions (advancement or termination) and in the development of de-risking strategies for backup compounds, thus playing a critical role in helping to reduce the late attrition of drugs and chemicals. Maintaining GLP compliance is often perceived as a costly and cumbersome process; a common and short-term strategy to reduce the costs is to outsource regulatory toxicity studies. However, there are significant advantages in maintaining the GLP status for toxicologic pathology activities in-house including the sustainable retention of internal pathology expertise that has maintained the necessary training needed to manage GLP studies. [Box: see text].

International Harmonization of Nomenclature and Diagnostic Criteria (INHAND): Nonproliferative and Proliferative Lesions of the Rabbit.

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 non-proliferative 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 laboratory rabbit 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.

Proceedings of the 2019 National Toxicology Program Satellite Symposium.

The 2019 annual National Toxicology Program Satellite Symposium, entitled "Pathology Potpourri," was held in Raleigh, North Carolina, at the Society of Toxicologic Pathology's 38th annual meeting. The goal of this symposium was to present and discuss challenging diagnostic pathology and/or nomenclature issues. This article presents summaries of the speakers' talks along with select images that were used by the audience for voting and discussion. Various lesions and topics covered during the symposium included aging mouse lesions from various strains, as well as the following lesions from various rat strains: rete testis sperm granuloma/fibrosis, ovarian cystadenocarcinoma, retro-orbital schwannoma, periductal cholangiofibrosis of the liver and pancreas, pars distalis hypertrophy, chronic progressive nephropathy, and renal tubule regeneration. Other cases included polyovular follicles in young beagle dogs and a fungal blood smear contaminant. One series of cases challenged the audience to consider how immunohistochemistry may improve the diagnosis of some tumors. Interesting retinal lesions from a rhesus macaque emphasized the difficulty in determining the etiology of any particular retinal lesion due to the retina's similar response to vascular injury. Finally, a series of lesions from the International Harmonization of Nomenclature and Diagnostic Criteria Non-Rodent Fish Working Group were presented.

Proceedings of the 2018 National Toxicology Program Satellite Symposium.

The 2018 annual National Toxicology Program Satellite Symposium, entitled "Pathology Potpourri," was held in Indianapolis, Indiana, at the Society of Toxicologic Pathology's 37th annual meeting. The goal of this symposium was to present and discuss challenging diagnostic pathology and/or nomenclature issues. This article presents summaries of the speakers' talks along with select images that were used by the audience for voting and discussion. Various lesions and other topics covered during the symposium included seminiferous tubule dysgenesis in rats, ameloblast and odontoblast degeneration/necrosis in a Sprague Dawley rat, intestinal leiomyositis in a beagle dog, gallbladder mucinous hyperplasia, focus of hepatocellular alteration and bile duct alteration in otters, renal tubule cytoplasmic vacuolation with basophilic granules in mice treated swith antisense oligonucleotide therapy, a uterine choriocarcinoma in a rhesus macaque, and rete ovarii proliferative ovarian lesions in various aged rat strains. One particularly provocative lesion was a malignant neoplastic proliferation in the renal pelvic region of a cynomolgus macaque from a 21-day study. Additional challenging lesions included thyroid proliferative lesions in zebra fish and gross findings in fish larvae during routine chemical screening. The Rabbit and Minipig International Harmonization of Nomenclature and Diagnostic Criteria Organ Working Groups also presented a series of challenging lesions.

Best Practice Approach for Assessment of Microchip-associated Tumors in Preclinical Safety Studies: Position of the Registry of Industrial Toxicology Animal-data (RITA).

Microchip (passive radio-frequency identification device) implantation is a common and widely employed means of animal identification in laboratory animal facilities. However, these devices have been associated with tumors of the skin and subcutis in rodents. While microchip-associated tumors are rare, they pose a challenge for accurate diagnosis and documentation in preclinical toxicity studies. Documentation of these tumors should differentiate microchip-associated lesions with spontaneously occurring or test article-induced tumors. Standardizing criteria for microchip-associated lesions will aid the diagnostic process and allow for preclinical regulatory standardization. To this end, the Registry of Industrial Toxicology Animal-data have developed clear recommendations for diagnosis and documentation of microchip-associated lesions.

Non-proliferative and Proliferative Lesions of the Cardiovascular System of the Rat and Mouse.

The INHAND Project (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions in Rats and Mice) is a joint initiative of the Societies of Toxicologic Pathology from Japan (JSTP), Europe (ESTP), Great Britain (BSTP) and North America (STP) to develop an internationally-accepted nomenclature for proliferative and non-proliferative lesions in laboratory animals. The primary purpose of this publication is to provide a standardized nomenclature for characterizing lesions observed in the cardiovascular (CV) system of rats and mice commonly used in drug or chemical safety assessment. The standardized nomenclature presented in this document is also available electronically for society members on the internet (http://goreni.org). Accurate and precise morphologic descriptions of changes in the CV system are important for understanding the mechanisms and pathogenesis of those changes, differentiation of natural and induced injuries and their ultimate functional consequence. Challenges in nomenclature are associated with lesions or pathologic processes that may present as a temporal or pathogenic spectrum or when natural and induced injuries share indistinguishable features. Specific nomenclature recommendations are offered to provide a consistent approach.

Nonproliferative and Proliferative Lesions of the Rat and Mouse Skeletal Tissues (Bones, Joints, and Teeth).

The INHAND (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions in Rats and Mice) Project (www.toxpath.org/inhand.asp) is an initiative of the Societies of Toxicological 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 the skeletal tissues and teeth of laboratory rats and mice, with color photomicrographs illustrating examples of many common lesions. The standardized nomenclature presented in this document is also available on the internet (http://www.goreni.org/). Sources of material were databases from government, academic and industrial laboratories throughout the world.

Proliferative and non-proliferative lesions of the rat and mouse soft tissue, skeletal muscle and mesothelium.

The INHAND Project (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions in Rats and Mice) 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 lesions observed in the soft tissues including skeletal muscle as well as the mesothelium of rats and mice. The standardized nomenclature of lesions 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 developmental and aging lesions as well as those induced by exposure to test materials. A widely accepted and utilized international harmonization of nomenclature for lesions in soft tissues, skeletal muscle and mesothelium in laboratory animals will decrease confusion among regulatory and scientific research organizations in different countries and provide a common language to increase and enrich international exchanges of information among toxicologists and pathologists. (DOI: 10.1293/tox.26.1S; J Toxicol Pathol 2013; 26: 1S-26S).

Proceedings of the 2012 National Toxicology Program Satellite Symposium.

The 2012 annual National Toxicology Program (NTP) Satellite Symposium, entitled "Pathology Potpourri," was held in Boston in advance of the Society of Toxicologic Pathology's 31st annual meeting. The goal of the NTP Symposium is to present current diagnostic pathology or nomenclature issues to the toxicologic pathology community. This article presents summaries of the speakers' presentations, including diagnostic or nomenclature issues that were presented, along with select images that were used for audience voting or discussion. Some lesions and topics covered during the symposium include eosinophilic crystalline pneumonia in a transgenic mouse model; differentiating adrenal cortical cystic degeneration from adenoma; atypical eosinophilic foci of altered hepatocytes; differentiating cardiac schwannoma from cardiomyopathy; diagnosis of cardiac papillary muscle lesions; intrahepatocytic erythrocytes and venous subendothelial hepatocytes; lesions in Rathke's cleft and pars distalis; pernicious anemia and megaloblastic disorders; embryonic neuroepithelial dysplasia, holoprosencephaly and exencephaly; and INHAND nomenclature for select cardiovascular lesions.

The mixed network former effect in glasses: solid state NMR and XPS structural studies of the glass system (Na2O)(x)(BPO4)(1-x).

The structural organization of sodium borophosphate glasses with composition (Na(2)O)(x)(BPO(4))(1-x) (0.25 ≤x≤ 0.55) has been investigated by differential scanning calorimetry, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), as well as single- and double resonance (11)B and (31)P magic-angle spinning (MAS) NMR. (11)B MAS-NMR data indicate the dominance of anionic four-coordinated boron units, and (31)P MAS NMR reveals the successive transformation of neutral P(3) into singly charged P(2) units and their further transformation into doubly charged P(1) units at high Na(2)O contents. The quantification of these units provides detailed insight into the competition of the network formers borate and phosphate for the network modifier oxide. At low modifier content (x < 0.35), the anionic species are almost exclusively borate (B(4)) units, whereas at higher sodium concentrations, large numbers of anionic phosphate (P(2) and P(1)) species are formed. O-1s XPS data provide a quantitative distinction between B-O-B, B-O-P, and P-O-P linkages as well as non-bridging oxygen atoms, and comparable numbers can be extracted from (11)B and (31)P MAS-NMR experiments. Both XPS as well as (31)P{(11)B} and (11)B{(31)P} rotational echo double resonance (REDOR) NMR results reveal strong interactions between the two network formers boron oxide and phosphorus oxide, resulting in a preferred formation of B-O-P linkages. For higher Na(2)O contents, however, the successive network modification diminishes this preference, resulting in close-to-statistical network connectivities. Compositional trends of T(g) in the Na(2)O-B(2)O(3)-P(2)O(5) glass forming system can be correlated with the overall network connectedness, expressed by the total number of bridging oxygen atoms per network former species. However, separate linear correlations are observed for different compositional lines, indicating also the relevance of the type of network former linkages present.

RITA--Registry of Industrial Toxicology Animal data: the application of historical control data for Leydig cell tumors in rats.

Historical data for Leydig cell tumors from untreated or vehicle treated rats from carcinogenicity studies collected in the RITA database are presented. Examples are given for analyses of these data for dependency on variables considered to be of possible influence on the spontaneous incidence of Leydig cell tumors. In the 7453 male rats available for analysis, only one case of a Leydig cell carcinoma was identified. The incidence of Leydig cell adenomas differed markedly between strains. High incidences of close to 100% have been found in F344 rats, while the mean incidence was 4.2% in Sprague-Dawley rats and 13.7% in Wistar rats. Incidences in Wistar rats were highly variable, primarily caused by different sources of animals. Mean incidences per breeder varied from 2.8 to 39.9%. Analyses for the dependency on further parameters have been performed in Wistar rats. In breeders G and I, the Leydig cell tumor incidence decreased over the observation period and with increasing mean terminal body weight. The incidence of Leydig cell tumors increased with mean age at necropsy and was higher in studies with dietary admixture compared to gavage studies. These parameters had no effect on Leydig cell tumor incidence in breeders A and B. Animals from almost all breeders had a considerably higher mean age at necropsy when bearing a Leydig cell adenoma than animals without a Leydig cell adenoma. Studies with longitudinal trimming of the testes had a higher incidence than studies with transverse trimming. The observed dependencies and breeder differences are discussed and explanations are given. Consequences for the use of historical control data are outlined. With the retrospective analyses presented here we were able to confirm the published features of Leydig cell adenomas and carcinomas. This indicates that the RITA database is a valuable tool for analyses of tumors for their biological features. Furthermore, it demonstrates that the RITA database is highly beneficial for the definition of reliable historical control data for carcinogenicity studies on a scientifically solid basis.

Sodium distribution in mixed alkali K-Na metaphosphate glasses.

The local order and distribution of Na in the mixed alkali metaphosphate glasses K(x)Na(1-x)PO(3) were analyzed, with the aim to identify segregation or a random mixture of both cation species. X-Ray photoelectron spectroscopy and several nuclear magnetic resonance (NMR) techniques were applied, including (31)P and (23)Na high-resolution spectroscopy, (23)Na triple quantum-MAS NMR, rotational echo double resonance between (31)P and (23)Na, and (23)Na NMR spin echo decay. The structural picture emerging from these results reveals the similarity in the local Na environments in the glasses but also subtle structural adjustments with increasing degree of K replacement. While both cations are intimately mixed at the atomic scale, the (23)Na spin echo decay data suggest a detectable like-cation preference in the spatial distribution of the ions. These structural properties are consistent with those determined in Li-Rb metaphosphates, indicating that the origin of the mixed alkali effect observed in the conductivity of Na-K metaphosphate glasses may also be explained by structurally blocked ion diffusion.

Characterization of streptavidin binding to biotinylated, binary self-assembled thiol monolayers--influence of component ratio and solvent.

Many biosensor applications are based on streptavidin (SA) binding to partially biotinylated self-assembled thiol monolayers (SAMs). In our study, binary SAMs on gold were prepared from solutions containing 16-mercapto-1-hexadecanol (thiol I) and N-(8-biotinyl-3,6-dioxa-octanamidyl)-16-mercaptohexadecanamide (thiol II) in varying component ratios. Either chloroform or ethanol was used as solvent. After 24 h thiol incubation, SA was immobilized on the resulting SAMs using the strong SA-biotin interaction. The SA binding process was monitored by QCM-D (quartz crystal microbalance monitoring dissipation factor). It is shown that the Sauerbrey equation is valid to calculate the mass quantities of the immobilized SA layers. Under the chosen incubation conditions, marginal fractions of the biotinylated component II in chloroform ((n(I)/n(II))(solution) approximately = 1000) lead to SAMs which ensure a maximal SA binding quantity of m(Sauerbrey SA) approximately = 400 ng x cm(-2), being equivalent to a SA single-layer arrangement on the SAM surface. In case of incubations from ethanolic solutions, a complete SA layer formation needs significantly higher amounts of the biotinylated component II during SAM preparation ((n(I)/n(II))(solution) approximately = 50). X-ray photoelectron spectroscopy data show that the fraction of biotinylated thiol II in the SAM determines the amount of surface-bound SA. The SAM thiol ratio ((n(I)/n(II))(SAM)) not only depends on the corresponding component ratio in the incubation solution, but is also strongly influenced by the solvent. Using chloroform as solvent during SAM preparation significantly increased the fraction of biotinylated thiol II in the SAMs compared to ethanol.

Proceedings of the 2009 National Toxicology Program Satellite Symposium.

The National Toxicology Program (NTP) Satellite Symposium is a one-day meeting that is held in conjunction with the annual Society of Toxicologic Pathology (STP) meeting. The topic of the 2009 Symposium was "Tumor Pathology and INHAND (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions in Rats and Mice) Nomenclature." The goal of this article is to provide summaries of each speaker's presentation, including the diagnostic or nomenclature issues that were presented, along with a few select images that were used for voting. The results of the voting process and interesting points of discussion that were raised during the presentation are also provided. A supplemental file with voting choices and voting results for each case presented at the symposium is available at http://tpx.sagepub.com/supplemental.

Reactive and proliferative changes of splenic reticulum cells of rats investigated with special staining methods and immunohistochemistry.

In the rat spleen, reactive and proliferative changes of the reticulum cells are rare events and seem to occur almost exclusively in the red pulp. The normal structure of the splenic reticulum cell and fiber lattice and examples of spontaneous and induced pathological alterations were investigated by immunohistochemistry (smooth muscle-actin, vimentin, S100 and proliferating cell nuclear antigen) and special stains for extracellular fibers (silver impregnation, azan). In response to congestion, systemic tumor growth or treatment with a hematotoxic compound, the scaffold cells increased either their contractile properties or their production of extracellular fibers. Primary focal hyperplasias of stromal cells which had developed without obvious cause were characterized by vanishing of sinuses, increased fiber content, increased expression of sm-actin or foci of lipomatosis. The borders of focal hyperplasias were indistinct and they did not infiltrate the white pulp compartments. Neoplasms of the stromal reticulum cells resembled soft tissue tumors in other organs. Specific tumor entities as described in other species have so far not been observed in the rat.

ESTP comments on the draft updated OECD test guideline 407.

The revision of the OECD TG 407 test guideline (repeated dose 28-day oral toxicity study in rodents) focuses on endpoints to detect endocrine activities of chemicals. The new endpoints are likely to influence other previously established core endpoints of this study type. An expert group of pathologists and toxicologists within the European Society of Toxicologic Pathologists (ESTP) has contributed to the scientific discussion of the draft guideline. The advantages and disadvantages of methodical changes as necropsy of all females in dioestrus, blood collection for clinical chemistry and haematology at the same cycle stage, weighing of the thyroid gland and separate weighing of ventral and dorsolateral lobes of the prostate are considered. Possible alternatives are pointed out covering scientific as well as practical aspects.

Structural integration of tellurium oxide into mixed-network-former glasses: connectivity distribution in the system NaPO(3)-TeO(2).

Sodium phosphate tellurite glasses in the system (NaPO(3))(x)(TeO(2))(1-) (x) were prepared and structurally characterized by thermal analysis, vibrational spectroscopy, X-ray photoelectron spectroscopy (XPS) and a variety of complementary solid-state nuclear magnetic resonance (NMR) techniques. Unlike the situation in other mixed-network-former glasses, the interaction between the two network formers tellurium oxide and phosphorus oxide produces no new structural units, and no sharing of the network modifier Na(2)O takes place. The glass structure can be regarded as a network of interlinked metaphosphate-type P(2) tetrahedral and TeO(4/2) antiprismatic units. The combined interpretation of the O 1s XPS data and the (31)P solid-state NMR spectra presents clear quantitative evidence for a nonstatistical connectivity distribution. Rather, the formation of homoatomic P--O--P and Te--O--Te linkages is favored over mixed P--O--Te connectivities. As a consequence of this chemical segregation effect, the spatial sodium distribution is not random, as also indicated by a detailed analysis of (31)P/(23)Na rotational echo double-resonance (REDOR) experiments.