Use of whole-genome sequence data and novel genomic selection strategies to improve selection for age at puberty in tropically-adapted beef heifers.

BACKGROUND: In tropically-adapted beef heifers, application of genomic prediction for age at puberty has been limited due to low prediction accuracies. Our aim was to investigate novel methods of pre-selecting whole-genome sequence (WGS) variants and alternative analysis methodologies; including genomic best linear unbiased prediction (GBLUP) with multiple genomic relationship matrices (MGRM) and Bayesian (BayesR) analyses, to determine if prediction accuracy for age at puberty can be improved. METHODS: Genotypes and phenotypes were obtained from two research herds. In total, 868 Brahman and 960 Tropical Composite heifers were recorded in the first population and 3695 Brahman, Santa Gertrudis and Droughtmaster heifers were recorded in the second population. Genotypes were imputed to 23 million whole-genome sequence variants. Eight strategies were used to pre-select variants from genome-wide association study (GWAS) results using conditional or joint (COJO) analyses. Pre-selected variants were included in three models, GBLUP with a single genomic relationship matrix (SGRM), GBLUP MGRM and BayesR. Five-way cross-validation was used to test the effect of marker panel density (6 K, 50 K and 800 K), analysis model, and inclusion of pre-selected WGS variants on prediction accuracy. RESULTS: In all tested scenarios, prediction accuracies for age at puberty were highest in BayesR analyses. The addition of pre-selected WGS variants had little effect on the accuracy of prediction when BayesR was used. The inclusion of WGS variants that were pre-selected using a meta-analysis with COJO analyses by chromosome, fitted in a MGRM model, had the highest prediction accuracies in the GBLUP analyses, regardless of marker density. When the low-density (6 K) panel was used, the prediction accuracy of GBLUP was equal (0.42) to that with the high-density panel when only six additional sequence variants (identified using meta-analysis COJO by chromosome) were included. CONCLUSIONS: While BayesR consistently outperforms other methods in terms of prediction accuracies, reasonable improvements in accuracy can be achieved when using GBLUP and low-density panels with the inclusion of a relatively small number of highly relevant WGS variants.

Multivariate genomic predictions for age at puberty in tropically adapted beef heifers.

Heifers that have an earlier age at puberty often have greater lifetime productivity. Age at puberty is moderately heritable so selection should effectively reduce the number of days to puberty, and improve heifer productivity and profitability as a result. However, recording age at puberty is intensive, requiring repeat ovarian scanning to determine age at first corpus luteum (AGECL). Genomic selection has been proposed as a strategy to select for earlier age at puberty; however, large reference populations of cows with AGECL records and genotypes would be required to generate accurate GEBV for this trait. Reproductive maturity score (RMS) is a proxy trait for age at puberty for implementation in northern Australia beef herds, where large scale recording of AGECL is not feasible. RMS assigns a score of 0 to 5 from a single ovarian scan to describe ovarian maturity at ~600 d. Here we use multivariate genomic prediction to evaluate the value of a large RMS data set to improve accuracy of GEBV for age at puberty (AGECL). There were 882 Brahman and 990 Tropical Composite heifers with AGECL phenotypes, and an independent set of 974 Brahman, 1,798 Santa Gertrudis, and 910 Droughtmaster heifers with RMS phenotypes. All animals had 728,785 real or imputed SNP genotypes. The correlation of AGECL and RMS (h2 = 0.23) was estimated as -0.83 using the genomic information. This result also demonstrates that using genomic information it is possible to estimate genetic correlations between traits collected on different animals in different herds, with minimal or unknown pedigree linkage between them. Inclusion of heifers with RMS in the multi-trait model improved the accuracy of genomic evaluations for AGECL. Accuracy of RMS GEBV generally did not improve by adding heifers with AGECL phenotypes into the reference population. These results suggest that RMS and AGECL may be used together in a multi-trait prediction model to increase the accuracy of prediction for age at puberty in tropically adapted beef cattle.

Towards multi-breed genomic evaluations for female fertility of tropical beef cattle.

Developing accurate genomic evaluations of fertility for tropical beef cattle must deal with at least two major challenges (i) recording cow fertility traits in extensive production systems on large numbers of cows and (ii) the genomic evaluations should work across the breeds, crossbreds, and composites used in tropical beef production. Here, we assess accuracy of genomic evaluations for a trait which can be collected on a large scale in extensive conditions, corpus luteum score (CLscore), which is 1 if ovarian scanning indicates a heifer has cycled by 600 d and 0 if not, in a multi-breed population. A total of 3,696 heifers, including 979 Brahmans, 914 Droughtmasters, and 1,803 Santa Gertrudis in seven herds across 3-yr cohorts with CLscores, were genotyped for 24,211 SNPs. Genotypes were imputed to 728,785 SNPs. GBLUP and BayesR were used to predict GEBV. Accuracy of GEBV was evaluated with two validation strategies. In the first strategy, the last year cohort of heifers from each herd was used for validation, such that every herd had heifers in both reference and validation populations. In the second validation strategy, each herd in turn was removed in its entirety from the reference population, and was used for validation. For both validation strategies, accuracy of GEBV for single breed and multi-breed reference populations was assessed. For the first validation strategy, accuracy of GEBV ranged from 0.2 for Brahmans to 0.4 for Droughtmasters. Increasing marker density from 24K SNPs to 728K SNPs resulted in a small increase in accuracy, and including multiple-breeds in the reference did not help improve accuracy. These results suggest that provided a herd has animals in the reference population, the accuracy of the GEBV is largely determined by within herd (linkage) information. The situation was very different when entire herds were predicted in the second validation. In this case accuracy of GEBV using only 24K SNPs and only a within breed reference was close to zero for all breeds. Accuracy increased substantially when 728K SNPs, BayesR, and a multi-breed reference were used, from 0.15 for Brahmans to 0.35 for Santa Gertrudis. Given the second validation strategy is more likely to reflect the situation for many herds in tropical beef production (no animals in the reference), genomic evaluations for fertility in tropical beef cattle should be based on high-density markers (728K SNPs) and should be multi-breed.

Ultrasonographic measurements in first trimester concepti identify predictors of birth weight and postnatal development in cattle.

The placenta is a major driver of prenatal growth and involved in programming of postnatal performance. We therefore determined placental and embryo-fetal ultrasonographic parameters in early pregnancy and their relationships with birth weight and postnatal weights in a Bos indicus-Bos taurus composite beef cattle population. Pregnancies were generated in 2-yr-old Droughtmaster heifers by artificial insemination after estrus synchronization in 2 consecutive years (2009, n = 36 and 2010, n = 57), with a subset of 2010 heifers used again as lactating 3-yr-old cows in 2011 (n = 24). Each cohort was managed as 1 contemporary group for measurements of Corpus luteum diameter, amnion length and width, placentome width and thickness, and embryo-fetal crown-rump length, at 7 and 8 wk of gestation. This was followed by recordings of birth weight, branding weight at 5 to 6 mo of age and weaning weight 2 mo later. At a significance threshold of P < 0.05, placentome thickness at week 7 was negatively correlated with weights at birth (r = -0.23), branding (r = -0.25), and weaning (r = -0.35), whereas placentome width at week 7 (r = 0.24) and thickness at week 8 (r = 0.29) were positively correlated with birth weight. Thicker placentomes in males at week 7 (7%) difference mirrored sex differences in weights at birth (7%), branding (10%), and weaning (6%). The sex difference trend for birth weight was not consistent across sire-year combinations, ranging from -3.2 to +4.7 kg (birth weight of males - females per sire). These results support the hypothesis that placental parameters at the transition from embryo to fetal stage are major predictors of fetal and postnatal growth, albeit with significant environmentally induced plasticity, in stabilized B. indicus-B. taurus composite populations, and suggest that elements of B. indicus-B. taurus reciprocal differences in birth weight persist in composite populations.

Decompressive Medial Cuneiform Exostectomy for Resistant Tibialis Anterior Insertional Tendinopathy.

Distal tibialis anterior tendinopathy, as a clinical entity, has only recently been documented in foot and ankle studies. We report our experience with medial cuneiform decompressive exostectomy and superficial tendon debridement in 14 cases of recalcitrant tibilalis anterior insertional pain. We reviewed 13 patients (14 feet; 12 females, 1 male; mean age 67.9 ± 7.5; range 55 to 80 years) in whom conservative treatment had failed who had undergone debridement of the insertional tibialis anterior tendon and decompressive exostectomy of the medial cuneiform. Pre- and postoperative American Orthopaedic Foot and Ankle Society (AOFAS) midfoot scale and visual analog scale (VAS) pain scores, local clinical findings, and dorsiflexion power at an average follow-up period of 28 ± 17.9 (range 6 to 55) months were assessed. All patients had experienced burning, nocturnal, medial midfoot pain and disability. The symptom longevity preoperatively was 8.5 ± 3.1 (range 6 to 17) months. Peritendinous or intrasubstance signal changes were noted on magnetic resonance imaging in 10 feet (71%). The mean preoperative VAS pain score was 8.7 ± 1.3 (range 5 to10), whereas postoperative it was 0.4 ± 0.5 (range 0 to1) (p = .001). The mean preoperative and postoperative AOFAS midfoot scale score was 54 ± 14.5 (range 20 to 70) and 91 ± 6.8 (range 79 to 100), respectively (p = .001). Postoperative ankle dorsiflexion power was normal and local tenderness had resolved in all patients. One patient (7.1%) stumbled at 2 weeks, resulting in avulsion of the tibialis anterior tendon, requiring transosseous fixation and gastrocnemius recession. All patients reported satisfaction with the surgical outcome and willingness to undergo the surgery again if necessary. A combination of medial cuneiform mechanical decompression and insertional tendon debridement can offer successful outcomes in resistant insertional tibialis anterior tendinopathy.

The complications of septic arthritis in the elderly.

BACKGROUND AND AIMS: An epidemiological analysis of cases of spontaneous community acquired septic arthritis in an elderly population at a university teaching hospital. METHODS: Confirmed cases of spontaneous septic arthritis in the over-65 population were studied. Patients with prosthetic joint infections were excluded from the study. Analysed data included initial presenting complaint and clinical examination, hematological and microbiological tests together with ultimate patient outcome. RESULTS: There were 7 confirmed cases of spontaneous septic arthritis in the over 65 population in the past 6 months (2 hips, 5 knees). The mean age was 72.14 (range 65-82) with a mean length of stay of 49 days. Those with septic arthritis of the knee presented with swelling, pain and immobility. Hip cases presented with pain and immobility. All patients were systemically well at the time of presentation, with no other foci of infection detected after septic screening. All patients had confirmed aspirate and arthroscopic/arthrotomy infection. Staphylococcus aureus was isolated from 6 joint aspirations and Pseudomonas Aeruginosa from one patient. Complications of treatment included acute renal failure, cardio/respiratory failure, disseminated infection, and death (1 case). CONCLUSION: Septic arthritis must be considered as a differential diagnosis in all patients with joint pain, swelling and immobility. This diagnosis is not confined to the pediatric population. A background of degenerative disease and occult presentation in the elderly may delay diagnosis. Sepsis must be considered in the elderly with joint pathology, and treatment must be initiated in a prompt and aggressive manner, to prevent sequelae.

C1 lateral mass screw-induced occipital neuralgia: a report of two cases.

C1-2 polyaxial screw-rod fixation is a relatively new technique. While recognizing the potential for inadvertent vertebral artery injury, there have been few reports in the literature outlining all the possible complications. Aim of this study is to review all cases of C1 lateral mass screws insertion with emphasis on the evaluation of potential structures at risk during the procedure. We retrospectively reviewed all patients in our unit who had C1 lateral mass screw insertion over a 2-year period. The C1 lateral mass screw was inserted as part of an atlantoaxial stabilization or incorporated into a modular occiput/subaxial construct. Outcome measures included clinical and radiological parameters. Clinical indicators included age, gender, neurologic status, surgical indication and the number of levels stabilized. Intraoperative complications including blood loss, vertebral artery injury or dural tears were recorded. Postoperative pain distribution and neurological deficit were recorded. Radiological indicators included postoperative plain radiographs to assess sagittal alignment and to check for screw malposition or construct failure. A total of 18 lateral mass screws were implanted in 9 patients. There were three male and six female patients who had C1 lateral mass screw insertion in this unit. Two patients had atlantoaxial stabilization for C2 fracture. There were four patients with rheumatoid arthritis whose C1 lateral mass screws were inserted as part of an occipitocervical or subaxial cervical stabilization. There was no vertebral artery injury, no cerebrospinal fluid leak and minimal blood loss in all patients. Three patients developed postoperative occipital neuralgia. This neuralgia was transient, in one of the patients having settled at 6-week follow-up. In the other two patients the neuralgia was unresolved at time of latest follow-up but was adequately controlled with appropriate pain management. Postoperatively no patient had radiographic evidence of construct failure and all demonstrated excellent sagittal alignment. It has been reported that the absence of threads on the upper portion of the long shank screw may protect against neural irritation. However, insertion of the C1 lateral mass screw necessitates careful caudal retraction of the C2 dorsal root ganglion. The insertion point for the C1 lateral mass screw is at the junction of the C1 posterior arch and the midpoint of the posterior inferior part of the C1 lateral mass. Two patients in our series suffered occipital neuralgia post-insertion of C1 lateral mass screws. This highlights the potential for damage to the C2 nerve root during C1 lateral mass screw placement.

Hypertonic saline reduces skeletal muscle injury and associated remote organ injury following ischemia reperfusion injury.

BACKGROUND AND PURPOSE: Pharmacological modulation of skeletal muscle reperfusion injury after traumaassociated ischemia may improve limb salvage rates and prevent the associated systemic sequelae. Resuscitation with hypertonic saline restores the circulating volume and has favorable effects on tissue perfusion and blood pressure. We evaluated the effects of treatment with a bolus of hypertonic saline on skeletal muscle ischemia reperfusion (IR) injury and the associated end-organ injury. METHODS: Adult male Sprague-Dawley rats (n = 27) were randomized into 3 groups: (1) a control group, (2) an IR group treated with normal saline, and (3) an IR group treated with hypertonic saline. Bilateral hindlimb ischemia was induced by application of a rubber band proximal to the level of the greater trochanters for 2.5 h. The treatment groups received either normal saline (4 mL/kg) or hypertonic saline (4 mL/kg) prior to tourniquet release. Following 12 h of reperfusion, the tibialis anterior muscle was dissected and muscle function was assessed electrophysiologically. The animals were then killed, and skeletal muscle and lung tissue were harvested for evaluation. RESULTS: Hypertonic saline significantly attenuated skeletal muscle reperfusion injury, as shown by reduced myeloperoxidase content, wet-to-dry ratio, and electrical properties of skeletal muscle. There was a corresponding reduction in lung injury, as demonstrated by reduced myeloperoxidase content and reduced wet-to-dry ratio. INTERPRETATION: Treatment with hypertonic saline attenuates skeletal muscle ischemia reperfusion injury and its associated systemic sequelae.

Statins attenuate polymethylmethacrylate-mediated monocyte activation.

BACKGROUND: Periprosthetic osteolysis precipitates aseptic loosening of components, increases the risk of periprosthetic fracture and, through massive bone loss, complicates revision surgery and ultimately is the primary cause for failure of joint arthroplasty. The anti-inflammatory properties of HMG-CoA reductase inhibitors belonging to the statin family are well recognized. We investigated a possible role for status in initiating the first stage of the osteolytic cycle, namely monocytic activation. METHODS: We used an in vitro model of the human monocyte/macrophage inflammatory response to poly-methylmethacrylate (PMMA) particles after pretreat-ing cells with cerivastatin, a potent member of the statin family. Cell activation based upon production of TNF-alpha and MCP-1 cytokines was analyzed and the intracellular Raf-MEK-ERK signal transduction pathway was evaluated using western blot analysis, to identify its role in cell activation and in any cerivastatin effects observed. RESULTS: We found that pretreatment with cerivastatin significantly abrogates the production of inflammatory cytokines TNF-alpha and MCP-1 by human monocytes in response to polymethylmethacrylate particle activation. This inflammatory activation and attenuation appear to be mediated through the intracellular Raf-MEK-ERK pathway. INTERPRETATION: We propose that by intervening at the upstream activation stage, subsequent osteoclast activation and osteolysis can be suppressed. We believe that the anti-inflammatory properties of statins may potentially play a prophylactic role in the setting of aseptic loosening, and in so doing increase implant longevity.

Improved tolerability of open carpal tunnel release under local anaesthetic: a patient satisfaction survey.

Carpal tunnel decompression is the most commonly performed procedure in hand surgery. This study was done to assess the effectiveness and acceptability by patients of open carpal tunnel release under local anaesthetic. We compare our results with both the literature and those of our previous study, after which were made alterations to improve the surgical and anaesthetic technique. These alterations included (a) injecting local anaesthetic with a dental syringe and a 27G needle in two stages along the proposed line of the incision and (b) omitting the use of a tourniquet, relying on the local anaesthetic with adrenaline to maintain a bloodless field during the procedure.