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BackgroundDrilling accuracy is essential in the correct positioning of implants and avoidance of iatrogenic damage to surrounding tissues. The use of augmented drilling methods has been documented as an approach to improving the accuracy of drilling. The aim of this study was to compare the accuracy of two augmented drilling methods (fluoroscopically guided and aiming device) to freehand (FH) drilling.MethodsThree experienced specialist surgeons and three veterinary surgeons without primary orthopaedic experience drilled into synthetic bone towards a target using the three different methods at three different angles (0°, 10° and 20°). The duration of drilling was recorded, and the accuracy of drilling was measured using photographs before and after drilling.ResultsThe two augmented methods were more accurate than FH drilling in synthetic bone, with the aiming device producing the greatest accuracy. Increased angulation of drilling decreased the drilling accuracy. Surgeon experience did not impact on drilling accuracy. Surgeon inexperience and augmented drilling methods both increased the time taken to drill.ConclusionThe use of augmented drilling methods improved the accuracy of drilling, and surgeons should consider their use when drilling in anatomical regions where the margin of error is small.

The accuracy of drill hole location is critical for implant placement in orthopaedic surgery. Increasing drill bit size sequentially has been suggested as a method for improving the accuracy of drill hole start location. The aim of this study was to determine whether sequential drilling or drill angulation would alter accuracy of drill hole start location. Three specialist veterinary surgeons drilled holes in synthetic bone models either directly, or with sequentially increasing drill bit sizes. Drilling was performed at 0o, 10o and 20o to perpendicular to the bone models. Three synthetic bone models were used to mimic canine cancellous and cortical bones. Sequential drilling resulted in greater inaccuracy in drill hole location when assessing all drilling angles together. There was no influence of surgeon or synthetic bone density on drilling accuracy. The combination of drill angulation and sequential drilling increased inaccuracy in drill hole start location. We conclude that sequential drilling decreased accuracy of drill hole location in the synthetic bone model when drilling was angled. Inaccuracy associated with the drill hole start location should be taken into account when performing surgery, although the magnitude of inaccuracy is low when compared with other sources of error such as angulation.

Hepatic encephalopathy is a frequent and debilitating complication of liver disorders. Lactulose is an established and reasonably effective treatment, yet with incompletely understood mechanisms of action. The aims of this study were to examine how the faecal microbiota composition changed before, during and after lactulose treatment in a large animal model. Healthy, privately owned dogs (n = 18) completed a prospective cohort study. Faecal samples were collected weekly, while the subjects were either on their usual diet (week 1), or a standardised diet (weeks 2–9), with added oral lactulose in weeks 6–7. DNA extraction and 16S rRNA gene sequencing were undertaken. Faecal samples from week 7 had a significantly lower microbiota richness/diversity, based on observed operational taxonomic units, Shannon/Chao1 indexes and Pielou’s Evenness. Beta diversity based on UniFrac distances was significantly different in week 7 compared to weeks 1, 5 and 9. At the phylum level, week 7 was associated with a significant increase of Firmicutes and Actinobacteria, and a decrease of Bacteroidetes and Fusobacteria, when compared to weeks 5 and 9. In summary, we have shown that lactulose induces a reversible qualitative and quantitative change of the faecal microbiota, which may explain its clinical efficacy in the management of hepatic encephalopathy.

The dna samples are available to all researchers with a bona fide interest in a particular disease or diseases, subject to providing an application and securing ethical approval. [...]all contributors can be assured that the maximum benefit will be gained from every sample collected.

Background: Collecting genomic information is crucial to advance breeding for complex traits such as health, welfare, and behaviour in domesticated populations. For that purpose, different data collection scenarios can be envisioned based on the number of individuals, the number of markers, and the genotyping technology. This study developed a simulation framework, based on a service dog population, aiming to identify an optimal and cost-effective genotyping strategy that would support the implementation of genomic selection, investigation of the genetic architecture of traits of interest, and track loci of interest. Methods: We simulated a population based on the existing pedigree, using the gene drop method in AlphaSimR. The existing pedigree was extended with additional progeny generations to evaluate the outcomes of different genotyping strategies in the future. We generated genotype data based on existing high-coverage whole-genome sequences (WGS) for the current breeding dogs and evaluated different scenarios for genotyping the progeny. The genotyping options considered SNP arrays of various densities and WGS callsets produced from different sequencing depths. We then phased and imputed the genotype data to high-coverage WGS using AlphaPeel. Results: All scenarios were compared based on individual imputation accuracy against the simulated true whole-genome genotype. Averaged over five generations of simulated progeny, low-pass sequencing (0.5 to 2X depth) achieved accuracies of 0.998 to 0.999. The accuracy of SNP array genotyping (25K to 710K markers) was lower, with means of 0.911 to 0.938. Conclusions: Our simulation was tailored to identify the most cost-effective and efficient strategy for downstream use in genomic selection and genetic research into traits and loci of interest. Low-pass sequencing outperformed SNP array genotyping in imputation accuracy of whole-genome genotypes as expected. Additionally, low-pass sequencing technology was the most affordable genotyping approach currently available for dogs. Thus, it appears to be the optimal choice for balancing the goals of regimented breeding programmes such as those that produce service dogs. This simulation framework could also be adapted to address other objectives for breeding organisations working with small populations.Competing Interest StatementThe authors have declared no competing interest.Footnotes* https://github.com/HighlanderLab/amartin_born2guide_seq

Osteoarthritis (OA) is a common debilitating disease ofmammalian joints. Canine OA was classically understood to arise secondary to articular diseases, such as elbow dysplasia, hip dysplasia and cranial cruciate ligament rupture which produced a mechanical dYllfunction of the affected joint. However it is now recognised that primary factors, such as genetics, govern the severity ofOA for a given articular disease. In this study, two different aspects ofthe genetic basis to OA were investigated; gene transcription in diseased tissues and gene polymorphism frequencies in populations of dogs with diseases predisposing to OA. Evaluation of the quality of extracted mRNA from canine joint tissues by rnicrofluidic electrophoresis traces revealed that there were no differences in the quality of samples extracted using either an isopropanol or ethanol precipitation method. However, a significant proportion ofRNA samples (32%) were identified as degraded, highlighting the importance of assessing RNA quality before usage. In OA canine hip cartilage, there was an increase in the gene expression of structural matrix molecules (collagens and small leucine rich proteoglycans) and proteinases (matrix metalloproteinase 13, cathepsin -B and -D), with concurrent decreased expression of selected inhibitors or protease activity (tissue inhibitors of metalloproteinase-2 and -4) when compared to normal articular cartilage using quantitative reverse transcriptase polymerase chain reaction (RT-qPCR) analyses. The general pattern of changes in matrix-associated gene expression was similar to that reported in naturally occurring human OA cartilage. Canine-specific oligonucleotide microarray gene expression profiling of a small sample set of normal and OA articular cartilage samples identified differential expression of a number of genes not previously associated with the disease. However, the high degree of heterogeneity observed in the expression profile data generated hampered subsequent data interpretation, and highlighted the limitations of expression profiling small sample sets with limited phenotype stringency. Quantification of matrix-associated gene expression in OA elbow cartilage by RT-qPCR identified changes which were consistent with those identified in end stage hip OA cartilage, and which correlated with the radiographic severity of elbow OA for a number of genes (such as type I collagen alpha two chain, type III collagen alpha one chain and tissue inhibitor of matrix metalloproteinase 2). Matrix metalloproteinase expression in OA elbow trabecular bone was also identified to be increased when compared to normal trabecular bone, when quantified by RT-qPCR. A general pattern of increased protease and extracellular structural matrix gene expression was identified in ruptured canine cranial cruciate ligaments (CCL) when compared to intact CCLs, with both RTqPCR and oligonucleotide microarray. No significant differences were identified between the gene expression profiles of normal CCLs of a breed predisposed to CCL rupture (Labrador Retriever) when compared to a breed relatively resistant to CCL rupture (Greyhound), although a degree of risk-specific clustering was observed for expression profiles of genes which were differentially expressed in CCL rupture. The expression profiles ofruptured canine CCLs were similar to those previously reported for ruptured human CCLs. A transcriptomic basis to breed specific risk for the development ofcanine CCL rupture was not identified. Microarray data sets generated from normal and OA canine articular cartilage and normal and ruptured CCL were filtered to identify new reference genes for use in RT-qPCR experiments. One of the new reference genes (Mitochondrial ribosomal protein S7 [MRPS7]) demonstrated a high degree of stability across multiple articular tissues from normal and OA canine joints, as determined by multiple, different reference gene stability assessment algorithms, making it a potential universal reference gene for use in canine OA tissue studies. Silica membrane spin columns provided the most consistent recovery of high quantities of genomic DNA (gDNA) from EDTA preserved and clotted blood samples without the co-extraction of PCR inhibitors, when compared to phenol-chloroform or modified salt precipitation methods of DNA extraction. Spectrophotometer quantification of extracted gDNA did not provide an accurate assessment of the functional gDNA quantity with phenol-chloroform extracted samples, because ofprotein contamination. Single nucleotide polymorphisrns (SNPs) were identified in twenty candidate genes and their allele frequencies evaluated in populations of Labrador Retrievers and Golden Retrievers with cruciate ligament disease, populations of Labrador Retrievers with elbow dysplasia and hip dysplasia and compared to general populations of Labradors Retrievers and Golden Retrievers. Significant associations were identified for the minor allele and haplotype frequencies of SNPs in interieukin 12B (ILI2B) in Labrador Retrievers with elbow dysplasia, interieukin 4 (IL4) and interieukin 6 (IL6) in Labrador Retrievers with hip dysplasia, IL4 and ILl2B in Labrador Retrievers with cranial cruciate ligament rupture, and interieukin 10 (ILID) and Ankyrin repeat domain 10 (ANKRDIO) in Golden Retrievers with cranial cruciate ligament rupture. A common genomic risk for the articular disease, or OA, was not identified between the two different breeds of dog evaluated, but common genomic risks were identified for different articular diseases within a single breed. A genetic basis to canine articular disease, or OA, was confirmed.