Acute Histopathologic Findings Related to Needle Puncture Trauma during Subcutaneous Injection in the Sprague-Dawley Rat Model.

It is important to detect injection site reactions during the nonclinical phases of drug development. However, differentiating between normal changes following needle trauma and changes due to the toxicity of injected drugs can be challenging. Therefore, we used the Sprague-Dawley rat model to evaluate the pathological findings expected following a single subcutaneous injection of normal saline. Rats were subcutaneously administered with normal saline, and the injection sites were examined microscopically. Inflammation was evident in most of the injection sites, mostly in minimal severity. Parakeratosis/epithelial crust was also seen in several sites, and necrosis was observed in a minority of the cases. These findings indicate that needle puncture trauma can present with some degree of inflammation and necrosis. Although limited to a specific time point and strain, this study shows that inflammation following subcutaneous injection can be attributed in part to the needle trauma and not necessarily to the drug itself.

Career Transition Points in Toxicologic Pathology: Management and Consulting.

In the constantly evolving field of toxicologic pathology, a pathologist's career is often characterized by multiple career transitions. However, these transitions can be challenging and/or overwhelming and may require a shift in focus, strategic approach, and acquisition of new skills and expertise. In order to provide a forum to discuss challenges associated with career transitions and skill set/competencies required to navigate career changes effectively and successfully, the Career Development and Outreach Committee of the Society of Toxicologic Pathology (STP) sponsored a career development workshop entitled "Transitions in a Pathologist's Career" in conjunction with the STP 36th annual symposium. The presentations at this workshop provided perspectives of managers from pharmaceutical companies and Contract Research Organizations as well as consultants. This article is designed to provide brief summaries of their talks in this well-received career development workshop.

Identification by whole genome sequencing of genes associated with delayed postoperative hemorrhage in Scottish deerhounds.

BACKGROUND: Delayed postoperative hemorrhage (DEPOH) is an important health concern for Scottish deerhounds. HYPOTHESIS/OBJECTIVES: Identify genes associated with DEPOH in Scottish deerhounds. ANIMALS: Two hundred sixty-nine privately owned Scottish deerhounds. METHODS: Retrospective case-control study. DEPOH cases and controls were identified through an owner health survey. Genome-wide association analysis was performed using whole genome sequences from 8 cases and 17 controls. All cases and controls were genotyped for selected variants. RESULTS: Of 269 dogs, 10 met inclusion and exclusion criteria for DEPOH, while 62 controls had undergone similar surgical procedures without DEPOH. Genome-wide association analysis identified a single locus on chromosome 9 spanning 40 genes. One of these genes (SERPINF2 encoding alpha-2 antiplasmin) was directly linked to the pathophysiology of DEPOH. The entire cohort was genotyped for a missense SERPINF2 variant (c.605 C>T; p.A202V). Compared to dogs with the reference C/C genotype, the likelihood of DEPOH was significantly higher for dogs with the T/T genotype (odds ratio [OR] = 1235; 95% confidence interval [CI] = 23-6752; P = 0.0005) and with the C/T genotype (OR = 28; 95% CI = 1.4-542; P = 0.03). CONCLUSIONS AND CLINICAL IMPORTANCE: SERPINF2 is associated with DEPOH in Scottish deerhounds. Genetic testing might be able to identify dogs that are susceptible to DEPOH.

Identification of 2,2-Dimethylbutanoic Acid (HST5040), a Clinical Development Candidate for the Treatment of Propionic Acidemia and Methylmalonic Acidemia.

Propionic acidemia (PA) and methylmalonic acidemia (MMA) are rare autosomal recessive disorders of propionyl-CoA (P-CoA) catabolism, caused by a deficiency in the enzymes P-CoA carboxylase and methylmalonyl-CoA (M-CoA) mutase, respectively. PA and MMA are classified as intoxication-type inborn errors of metabolism because the intramitochondrial accumulation of P-CoA, M-CoA, and other metabolites results in secondary inhibition of multiple pathways of intermediary metabolism, leading to organ dysfunction and failure. Herein, we describe the structure-activity relationships of a series of short-chain carboxylic acids which reduce disease-related metabolites in PA and MMA primary hepatocyte disease models. These studies culminated in the identification of 2,2-dimethylbutanoic acid (10, HST5040) as a clinical candidate for the treatment of PA and MMA. Additionally, we describe the in vitro and in vivo absorption, distribution, metabolism, and excretion profile of HST5040, data from preclinical studies, and the synthesis of the sodium salt of HST5040 for clinical trials.

A lifetime cancer bioassay of quinacrine administered into the uterine horns of female rats.

This study investigated if quinacrine can induce a tumorigenic response in rats when administered in a manner similar to the intended human use for female non-surgical sterilization. Young sexually mature female rats received two doses of quinacrine (or 1% methylcellulose control) into each uterine horn approximately 21 days apart, and were observed for 23 months after the second dose administration. Dose levels were 0/0, 0/0, 10/10, 70/70, and 70/250-350 mg/kg (first dose/second dose), which represent local doses in the uterus at approximate multiples of 1x, 8x and 40x the human dose (mg quinacrine/g uterine weight) used for female non-surgical sterilization. Rats were observed for viability, clinical signs of toxicity, and changes in body weight and food consumption. At necropsy, selected organs were weighed, macroscopic observations were recorded, and tissues were collected, fixed, processed, and examined for microscopic pathologic findings. Acute quinacrine toxicity was evident during the dosing period but did not affect long-term survival. Non-neoplastic findings were more common in treated animals than controls, providing evidence of the appropriateness of the bioassay. The incidence of uncommon tumors of the reproductive tract was similar to controls at doses of 10/10mg/kg but increased with dose level and was significantly greater than controls at >or=70/70 mg/kg. We conclude that two doses of quinacrine administered approximately 21 days apart into the uterus of young sexually mature rats at a local dose approximately 8 times the human dose used for non-surgical female sterilization increased the lifetime risk of tumor development in the reproductive tract.

Osteosarcoma inheritance in two families of Scottish deerhounds.

BACKGROUND: Osteosarcoma is the most common neoplastic disease in Scottish Deerhounds. For Deerhounds, a 2007 population-based study concluded that a single dominant genetic factor largely governed disease risk. For Greyhounds, Rottweilers, and Irish Wolfhounds, a 2013 genome-wide association study found multiple genetic markers in each breed, with each marker only weakly associated with the disease. We obtained from two breeders the pedigrees, age (if alive) or age at death, and osteosarcoma status for two families of Scottish Deerhounds, designated Cohorts K and T. A dog was considered unaffected only if it was osteosarcoma-free and at least 8.5 years old. We analyzed the data in two ways, by assuming either a single recessive genetic factor or a single dominant genetic factor with high penetrance. RESULTS: Cohort K contained 54 evaluable dogs representing 12 litters. Cohort T contained 56 evaluable dogs representing eight litters. Osteosarcoma seemed clearly heritable in both cohorts; however, having a parent with osteosarcoma raised a pup's risk of developing osteosarcoma to 38% for Cohort K but 78% for Cohort T, suggesting the possibility of different genetic risk factors in each cohort. In Cohort K, osteosarcoma inheritance fit well with a single, recessive, autosomal risk factor, although we could not rule out the possibility of a single dominant risk factor with incomplete penetrance. In Cohort T, inheritance could be explained well by a single, dominant, autosomal risk factor but was inconsistent with recessive expression. CONCLUSIONS: Inheritance of osteosarcoma in two Scottish Deerhound families could be explained well by a single genetic risk factor residing on an autosome, consistent with a 2007 report. In one family, inheritance was consistent with dominant expression, as previously reported. In the other family, inheritance fit better with recessive expression, although the possibility of a dominant genetic factor influenced by one or more other genetic factors could not be ruled out. In either case, the results suggest that there may be at least two different genetic risk factors for osteosarcoma in Deerhounds.

A one-year neonatal mouse carcinogenesis study of quinacrine dihydrochloride.

Quinacrine is an acridine derivative under investigation for its use in nonsurgical female sterilization. Safety issues regarding the carcinogenic potential of quinacrine have been raised because it is mutagenic and clastogenic in vitro. The objective of the study was to evaluate the carcinogenic potential of quinacrine dihydrochloride (quinacrine) in neonatal mice treated with single intraperitoneal doses on postpartum days 8 and 15 and observed for 52 weeks. Neonatal Crl: CD-1 mice of each sex were randomly allocated into four treatment groups (0, 10, 50, and 150 mg/kg), dosed twice with quinacrine suspended in carboxymethylcellulose, observed for 52 weeks post dose, and then euthanized, necropsied, and subjected to a full histopathological examination. In male mice, tumor incidence was not significantly increased at any site at any dose level. In female mice, the incidence of benign uterine endometrial stromal polyps was slightly greater at the mid and high dose (> or = 50 mg/kg), as was the incidence of endometrial hyperplasia. The incidence of polyps in these groups was not significantly greater than in controls by pair-wise comparison but was significantly greater (p = .042) by the linear trend test. The authors conclude that quinacrine administered twice to neonatal mice may have enhanced or accelerated the development of endometrial hyperplasia and uterine stromal polyps at higher doses. Because uterine stromal polyps are a commonly observed benign tumor in older mice, the significance of this finding is unclear and will require a weight of evidence evaluation for a conclusion on the carcinogenic potential of quinacrine.