Dose Characterization of the Investigational Anticancer Drug Tigilanol Tiglate (EBC-46) in the Local Treatment of Canine Mast Cell Tumors.

Mast cell tumor (MCT) is the most common cutaneous neoplasm in dogs and wide surgical resection is the current first-line treatment. However, recurrence is common and often requires more specialist and expensive therapies. Tigilanol tiglate is a novel small molecule drug delivered by intratumoral injection that is currently under development to provide a new option for treating MCT. The aim of this study was to characterize a safe and effective dose of tigilanol tiglate for canine MCT and to gather preliminary data on the drug's pharmacokinetics. A multicenter, open-label, uncontrolled, non-randomized, dose de-escalation design was used. Eligibility was MCT stage I/IIa and a tumor size of 0.1-6.0 cm3. Dosing was based on tumor size (50% v/v tumor) and 3 drug concentrations (1.0, 0.5, 0.2 mg/mL) were evaluated. Twenty-seven dogs were treated in 3 dose de-escalation cohorts (10, 10, and 7 dogs, respectively). Efficacy at 21 days was defined using international accepted solid tumor response criteria (RECIST). Greatest efficacy (90% complete response) was observed at the highest drug concentration (1.0 mg/mL) and adverse events were generally low grade, mild and transient, and directly associated with the mode of action of the drug. Hematological and serum biochemistry were generally unremarkable with plasma concentration curves typical of a non-intravenous parenteral medication. Intratumoral treatment of MCT with tigilanol tiglate at a concentration of 1.0 mg/mL was highly efficacious and well-tolerated. These results support the drug's further development for the treatment of MCT and other solid tumors.

Evolution of endogenous retroviruses in the Suidae: evidence for different viral subpopulations in African and Eurasian host species.

BACKGROUND: Porcine endogenous retroviruses (PERVs) represent remnants of an exogenous form that have become integrated in the domestic pig (Sus scrofa) genome. Although they are usually inactive, the capacity of γ1 ERVs to infect human cells in vitro has raised concerns about xenotransplantation because the viruses could cross the species barrier to humans. Here we have analyzed the evolution of γ1 ERVs in ten species of Suidae (suids, pigs and hogs) from Eurasia and Africa using DNA sequences for their coding domains (gag, pro/pol and env genes). For comparison with γ1 PERVs, we have also analysed γ2 ERVs which in domestic pigs are known to be inactive and do not pose a risk to xenotransplantation. RESULTS: Phylogenetic analysis using Bayesian inference showed that γ1 and γ2 ERVs have distinctive evolutionary histories. Firstly, two different viral lineages of γ1 ERVs were found and a coevolutionary analysis demonstrated that they correspond broadly to their host phylogeny, one of Eurasian and another of African species, and show no evidence of horizontal transmission. γ2 ERVs, however, show a bush-like evolution, suggesting a rapid viral radiation from a single common ancestor with no correspondence between host and viral evolutionary trees. Furthermore, though γ1 ERV env genes do not possess frequent stop codons, γ2 env genes do. To understand whether γ1 suid ERVs may be still replicating, we have also evaluated their likely mechanism of proliferation by statistically testing internal to terminal branches using nonsynonymous versus synonymous substitution ratios. Our results suggest that γ1 ERVs are increasing in copy number by reinfection, which requires the translocation of the virus from one cell to another. CONCLUSIONS: Evidence of at least two viral subpopulations was observed in γ1 ERVs from Eurasian and African host species. These results should be taken into account in xenotransplantation since γ1 ERVs appear to be codiverging with their host and maintaining ongoing capacity to infect somatic and germ cells.

Distinctive differences in long terminal repeat sequences between γ1 endogenous retroviruses of African and Eurasian suid species.

Diversity of long terminal repeats (LTRs) from γ1 endogenous retroviruses (ERVs) was analysed by DNA sequencing in 10 species of the family Suidae (suids, pigs and hogs). Phylogenetic analysis separated LTR sequences into two groups which correlated approximately with either the previously described cluster I and III, or the clusters II, IV and V. Interestingly, a specific LTR exhibiting a novel molecular rearrangement was identified exclusively within African host species when compared to LTRs previously reported from known ERVs in the domestic pig (Sus scrofa). Furthermore, other sections of LTRs appear to be unique to African suids as suggested by phylogenetic analysis. These differences between African and Eurasian ERV lineages show that these ERVs belong to different viral sub-populations, implying coevolution of endogenous viral sequences with their host species and providing no evidence of transfer of viral sequences between African and Eurasian suids.

Treatment of natural infestations of the biting louse (Werneckiella equi) on horses using triflumuron, a benzoylurea derivative insect growth regulator.

The horse biting louse (Werneckiella equi) is a common global equine ectoparasite. To our knowledge, benzoyl(phenyl)urea insecticides (triflumuron, diflubenzuron) commonly used as sheep lousicides, have not been evaluated for efficacy against W. equi. The aim of this study was to determine louse control efficacy, general wellness and dermal safety following triflumuron application as a backline pour-on to horses. Two efficacy trials using 25 adult naturally infested lousy horses, and a dermal safety trial using 10 adult louse-free horses were conducted over a 14-month period. Lousy animals were selected by assessment of their lice status prior to treatment. For the efficacy trial, the triflumuron product was applied at a dose of 2.5mg triflumuron per kg bodyweight (1 mL product per 10 kg bodyweight). For the safety study, triflumuron was applied at a 3x clinical dose of 7.5 mg triflumuron per kg bodyweight (3 mL product per 10 kg bodyweight). In our first efficacy trial, 100% lousicidal efficacy was achieved by day 44 post-treatment. In our second trial, no lice were identified on horses by day 71 post-treatment. In the safety trial, no adverse effects were seen. Results of this study demonstrate that the off-label, experimental pour-on application of triflumuron at 2.5 mg/kg bodyweight is convenient, highly effective and safe (at 3x the clinical dose) for the treatment of the horse biting louse, W. equi.

Macrophage transcriptional responses following in vitro infection with a highly virulent African swine fever virus isolate.

We used a porcine microarray containing 2,880 cDNAs to investigate the response of macrophages to infection by a virulent African swine fever virus (ASFV) isolate, Malawi LIL20/1. One hundred twenty-five targets were found to be significantly altered at either or both 4 h and 16 h postinfection compared with targets after mock infection. These targets were assigned into three groups according to their temporal expression profiles. Eighty-six targets showed increased expression levels at 4 h postinfection but returned to expression levels similar to those in mock-infected cells at 16 h postinfection. These encoded several proinflammatory cytokines and chemokines, surface proteins, and proteins involved in cell signaling and trafficking pathways. Thirty-four targets showed increased expression levels at 16 h postinfection compared to levels at 4 h postinfection and in mock-infected cells. One host gene showed increased expression levels at both 4 and 16 h postinfection compared to levels in mock-infected cells. The microarray results were validated for 12 selected genes by quantitative real-time PCR. Levels of protein expression and secretion were measured for two proinflammatory cytokines, interleukin 1beta and tumor necrosis factor alpha, during a time course of infection with either the virulent Malawi LIL20/1 isolate or the OUR T88/3 nonpathogenic isolate. The results revealed differences between these two ASFV isolates in the amounts of these cytokines secreted from infected cells.

Worldwide phylogeography of wild boar reveals multiple centers of pig domestication.

Mitochondrial DNA (mtDNA) sequences from 686 wild and domestic pig specimens place the origin of wild boar in island Southeast Asia (ISEA), where they dispersed across Eurasia. Previous morphological and genetic evidence suggested pig domestication took place in a limited number of locations (principally the Near East and Far East). In contrast, new genetic data reveal multiple centers of domestication across Eurasia and that European, rather than Near Eastern, wild boar are the principal source of modern European domestic pigs.

Novel herpesviruses of Suidae: indicators for a second genogroup of artiodactyl gammaherpesviruses.

Five novel herpesviruses were identified in suid species from Africa (common warthog, Phacochoerus africanus) and South-East Asia (bearded pig, Sus barbatus; babirusa, Babyrousa babyrussa) by detection and analysis of their DNA polymerase genes. Three of the novel species, P. africanus cytomegalovirus 1, P. africanus lymphotropic herpesvirus 1 (PafrLHV-1) and S. barbatus lymphotropic herpesvirus 1 (SbarLHV-1), were closely related to known beta- (porcine cytomegalovirus) and gammaherpesviruses [porcine lymphotropic herpesvirus (PLHV) 1 and 3] of domestic pigs. In contrast, two novel species, S. barbatus rhadinovirus 1 (SbarRHV-1) and Babyrousa babyrussa rhadinovirus 1 (BbabRHV-1), were more closely related to a ruminant gammaherpesvirus, bovine herpesvirus 4 (BoHV-4), than to the porcine gammaherpesviruses PLHV-1, -2, -3, PafrLHV-1 and SbarLHV-1. SbarRHV-1, BbabRHV-1 and BoHV-4 were therefore tentatively assigned to a novel genogroup of artiodactyl gammaherpesviruses. This latter genogroup may also contain an as yet undiscovered gammaherpesvirus of domestic pigs, thereby adding a concern to their use in xenotransplantation.