No abstract

To monitor rodent colony health in research facilities, soiled-bedding sentinel (SBS) animals have traditionally been used. SBS can be tested by various methods, which may include serology, PCR analysis, and necropsy. Several pathogens are unreliably detected by using SBS or transmitted poorly through soiled bedding, and collection and evaluation of SBS samples can be time-intensive. Recently, exhaust air dust (EAD) testing through PCR analysis has emerged as an adjunct or replacement method for rodent colony health monitoring. EAD monitoring may provide a more efficient, sensitive, and humane method for monitoring health status. Using both EAD and SBS health monitoring, we evaluated colony health over the course of 1 y in 3 research barrier rooms in which mice were housed exclusively on IVC racks. Three pathogens—Helicobacter spp., Rodentibacter spp. (previously Pasteurella pneumotropica), and murine norovirus (MNV)—were not excluded in 2 of the rooms, and we expected that these mice would test positive with some regularity. EAD monitoring was significantly more sensitive than SBS for detection of the bacterial agents. SBS failed to detect Helicobacter spp. at time points when EAD had 100% detection in the rooms that did not exclude the bacteria. The detection of MNV did not differ between health monitoring systems at any time point. The findings suggest that EAD is especially valuable in detecting bacteria poorly transmitted through soiled bedding. In addition, the corresponding results with MNV detection suggest that EAD surveillance can reliably be implemented as an alternative to SBS monitoring in a facility in which mice are housed exclusively on IVC racks.

Purpose In this study, the efficacy of transurethral prostate ablation in the presence of silica‐shell ultrasound‐triggered phase‐shift emulsions (sUPEs) doped with MR contrast was evaluated. The influence of sUPEs on MR imaging assessment of the ablation zone was also investigated. Methods sUPEs were doped with a magnetic resonance (MR) contrast agent, Gd2O3, to assess ultrasound transition. Injections of saline (sham), saline and sUPEs alone, and saline and sUPEs with Optison microbubbles were performed under guidance of a prototype interventional MRI navigation platform in a healthy canine prostate. Treatment arms were evaluated for differences in lesion size, T1 contrast, and temperature. In addition, non‐perfused areas (NPAs) on dynamic contrast‐enhanced (DCE) MRI, 55°C isotherms, and areas of 240 cumulative equivalent minutes at 43°C (CEM43) dose or greater computed from MR thermometry were measured and correlated with ablated areas indicated by histology. Results For treatment arms including sUPEs, the computed correlation coefficients between the histological ablation zone and the NPA, 55°C isotherm, and 240 CEM43 area ranged from 0.96–0.99, 0.98–0.99, and 0.91–0.99, respectively. In the absence of sUPEs, the computed correlation coefficients between the histological ablation zone and the NPA, 55°C isotherm, and 240 CEM43 area were 0.69, 0.54, and 0.50, respectively. Across all treatment arms, the areas of thermal tissue damage and NPAs were not significantly different (P = 0.47). Areas denoted by 55°C isotherms and 240 CEM43 dose boundaries were significantly larger than the areas of thermal damage, again for all treatment arms (P = 0.009 and 0.003, respectively). No significant differences in lesion size, T1 contrast, or temperature were observed between any of the treatment arms (P > 0.0167). Lesions exhibiting thermal fixation on histological analysis were present in six of nine insonations involving sUPE injections and one of five insonations involving saline sham injections. Significantly larger areas (P = 0.002), higher temperatures (P = 0.004), and more frequent ring patterns of restricted diffusion on ex vivo diffusion‐weighted imaging (P = 0.005) were apparent in lesions with thermal fixation. Conclusions T1 contrast suggesting sUPE transition was not evident in sUPE treatment arms. The use of MR imaging metrics to predict prostate ablation was not diminished by the presence of sUPEs. Lesions generated in the presence of sUPEs exhibited more frequent thermal fixation, though there were no significant changes in the ablation areas when comparing arms with and without sUPEs. Thermal fixation corresponded to some qualitative imaging features.

Ornithonyssus bacoti, commonly known as the tropical rat mite, is a zoonotic ectoparasite that occasionally infests research rodent colonies. Most infestations have been attributed to wild rodents that harbor the mite and spread it to research animals, often during building construction or other activity that disrupts wild rodent populations. Although infestation may be clinically silent, severe outbreaks have been reported to cause pruritis, dermatitis, decreased reproductive performance, and anemia in rodents. In mid 2020, our institution experienced increased activity of wild mice, which were found to be infested with O. bacoti, diagnosed by microscopic exam and confirmed by fur swab PCR analysis. We elected to add O. bacoti to our quarterly health monitoring exhaust air dust (EAD) testing PCR panel, increase wild mouse control measures, and treat the environment with a sustained-release synthetic pyrethroid spray in an attempt to prevent colony animal infestation. Initial quarterly EAD health monitoring results in September of 2020 were negative for O. bacoti. However, in early 2021, multiple IVC racks tested positive for O. bacoti at quarterly testing. Treatment consisted of providing permethrin soaked nesting material and surface spray treatment of the room and hallway with a sustained-release synthetic pyrethroid. Historically in the literature, O. bacoti outbreaks of research mice were not identified until mite burden was high enough to cause dermatitis on animal care workers. Due to modern molecular diagnostics and proactive PCR-based health monitoring surveillance, we were able to identify the outbreak earlier than would have otherwise been possible. To the best of our knowledge, this is the first report to successfully identify O. bacoti using environmental health monitoring PCR techniques. This outbreak demonstrates the importance of screening for O. bacoti in facilities with the potential for wild rodent infestation and highlights unique considerations when managing O. bacoti infestations. In addition, a novel permethrin-soaked enrichment item was developed for cage-level treatment.

Purpose: Epigenetic alterations in hepatocellular carcinoma (HCC) may facilitate cell survival under transarterial chemoembolization-induced ischemia by potentiating the function of canonical stress response pathways including the unfolded protein response (UPR), Hypoxia-Inducible Factor (HIF), and Autophagy. Moreover, the redundancy in function of these pathways makes inhibition of any single pathway insufficient to abrogate their function entirely. We hypothesize that HCC cells surviving severe TACE-like ischemia are susceptible to inhibition of these pathways and that combination of the inhibition of these pathways would lead to synergistic effects. Materials: Viability assays and cytotoxicity profiles of Huh-7, SNU-387 and SNU-449 HCC cell lines were studied under standard (21% O 2 with complete medium) and compared to severely ischemic conditions (1% O 2 , 1% serum, 1 mM glucose) with an inhibitor of the UPR (GSK2606141), a HIF-1 alpha inhibitor (PX-478 or BAY87-2243) and an inhibitor of autophagy (Hydroxychloroquine). Cytotoxicity measurements were derived from measured dose-response curves using the WST-1 cytotoxicity assay. The t-test was used to compare standard to severely ischemic conditions. Results: Each of the cell lines tested demonstrated decreased cellular viability with incubation of either of the inhibitory agents (EC50 GSK2606141, PX-478, BAY87-2243, Hydroxcychloroquine of 75-150μM, 50-100 μM, 300-600uM, and 100-200μM respectively). Ischemia potentiated the cytotoxicity (EC50 GSK2606141, PX-478, BAY87-2243, Hydroxcychloroquine of 25-50μM, 50-75 μM, 200-400uM, and 50-80μM respectively; with p<0.05 except for BAY87-2243). Combination inhibition of the three pathways under TACE-like ischemia lead to a synergistic response showing cell death at concentrations below any single drug alone (EC50 of BAY87-2243 in combination of 100-200uM compared to 400-500uM as a single agent). Conclusions: Inhibition of the UPR, HIF, and autophagy independently lead to cytotoxicity of HCC cells. Combination of the three drugs under TACE-like ischemia lead to a synergistic response and should be considered as potential chemotherapeutics for TACE.