Image quality and scan time optimisation for in situ phase contrast x-ray tomography of the intervertebral disc.

In-line phase contrast synchrotron tomography combined with in situ mechanical loading enables the characterisation of soft tissue micromechanics via digital volume correlation (DVC) within whole organs. Optimising scan time is important for reducing radiation dose from multiple scans and to limit sample movement during acquisition. Also, although contrasted edges provided by in-line phase contrast tomography of soft tissues are useful for DVC, the effect of phase contrast imaging on its accuracy has yet to be investigated. Due to limited time at synchrotron facilities, scan parameters are often decided during imaging and their effect on DVC accuracy is not fully understood. Here, we used previously published data of intervertebral disc phase contrast tomography to evaluate the influence of i) fibrous image texture, ii) number of projections, iii) tomographic reconstruction method, and iv) phase contrast propagation distance on DVC results. A greater understanding of how image texture influences optimal DVC tracking was obtained by visualising objective function mapping, enabling tracking inaccuracies to be identified. When reducing the number of projections, DVC was minimally affected by image high frequency noise but with a compromise in accuracy. Iterative reconstruction methods improved image signal-to-noise and consequently significantly lowered DVC displacement uncertainty. Propagation distance was shown to affect DVC accuracy. Consistent DVC results were achieved within a propagation distance range which provided contrast to the smallest scale features, where; too short a distance provided insufficient features to track, whereas too long led to edge effect inconsistencies, particularly at greater deformations. Although limited to a single sample type and image setup, this study provides general guidelines for future investigations when optimising image quality and scan times for in situ phase contrast x-ray tomography of fibrous connective tissues.

Extramitral Valvular Cardiac Involvement in Patients With Significant Secondary Mitral Regurgitation.

Patients with secondary mitral regurgitation (SMR) often have extramitral valve cardiac involvement, which can influence the prognosis. SMR can be defined according to groups of extramitral valve cardiac involvement. The prognostic implications of such groups in patients with moderate and severe SMR (significant SMR) are unknown. A total of 325 patients with significant SMR were classified according to the extent of cardiac involvement on echocardiography: left ventricular involvement (group 1), left atrial involvement (group 2), tricuspid valve and pulmonary artery vasculature involvement (group 3), or right ventricular involvement (group 4). The primary end point was all-cause mortality. The prevalence of each cardiac involvement group was 17% in group 1, 12% in group 2, 23% in group 3%, and 48% in group 4. Group 3 and group 4 were independently associated with all-cause mortality (hazard ratio 1.794, 95% confidence interval 1.067 to 3.015, p = 0.027 and hazard ratio 1.857, 95% confidence interval 1.145 to 3.012, p = 0.012, respectively). In conclusion, progressive extramitral valve cardiac involvement (group 3 and group 4) was independently associated with all-cause mortality in patients with significant SMR.

Sex differences in prognosis of significant secondary mitral regurgitation.

AIMS: Secondary mitral regurgitation (MR) is more frequent in men than in women. However, little is known about differences in prognosis between men and women with secondary MR. The objective of this study is to investigate the sex distribution of secondary MR and the prognostic differences between sexes. METHODS: Patients with significant secondary MR, of both ischaemic and non-ischaemic aetiologies, were identified through the departmental electronic patient files and retrospectively analysed. The primary endpoint was all-cause mortality. RESULTS: A total of 698 patients (mean age 66 ± 11 years) with significant secondary MR were included: 471 (67%) men and 227 (33%) women. Ischaemic heart failure was significantly more common in men (61%), whereas non-ischaemic heart failure was more prevalent in women (63%). Women had significantly smaller left ventricular (LV) volumes when compared with men and more preserved LV systolic function when assessed with LV global longitudinal strain (GLS; 8.5 ± 4.1% vs. 7.5 ± 3.6%; P = 0.004). Women more often underwent surgical mitral valve repair (34%) when compared with men (26%), although no differences were observed for transcatheter mitral valve repair. During a median follow-up of 57 [interquartile range 29-110] months, 373 (53%) patients died. Women showed significantly lower mortality rates at 1-, 2- and 5-year follow-up (9%, 16% and 33% vs. 10%, 20% and 42%) when compared with men (P = 0.001). CONCLUSIONS: Significant secondary MR is more frequently observed in men as compared with women and is associated with worse prognosis.

Mitral Valve Annulus Dimensions Assessment with Three-Dimensional Echocardiography Versus Computed Tomography: Implications for Transcatheter Interventions.

The aim of this study is to evaluate the agreement between three-dimensional (3D) transesophageal echocardiography (TEE) and multidetector computed tomography (MDCT) for assessing mitral annular (MA) dimensions. A total of 105 patients (79 ± 9 years old, 52% male) who underwent clinically indicated 3D TEE and MDCT feasible for MA geometrical assessment were included. Using dedicated semi-automated postprocessing software, MA geometry, including mitral annular area (MAA), perimeter, septal-lateral (SL) diameter, and inter-trigonal (TT) diameter, was evaluated using 3D TEE and MDCT. Compared to 3D TEE, MAA, perimeter, and SL distance measured on MDCT data were larger (9.9 ± 3.0 vs. 9.3 ± 3.1 cm2 for MAA; 115 ± 18 vs. 108 ± 18 mm for perimeter; and 35 ± 5 vs. 32 ± 5 cm for SL distance, all p < 0.001). By contrast, the TT distance was comparable between MDCT and 3D TEE (26 ± 4 vs. 26 ± 4 cm, p = 0.258). The correlations of all the MA dimensions were good to excellent between the two modalities (R = 0.911 for MAA, 0.890 for perimeter, 0.739 for TT distance, and 0.857 for SL distance, respectively, all p < 0.001). This study showed good agreement between 3D TEE- and MDCT-derived MA measurements although MDCT systematically provided larger MAA, perimeter, and SL distance compared with 3D TEE.

Insufficient Mitral Leaflet Remodeling in Relation to Annular Dilation and Risk of Residual Mitral Regurgitation After MitraClip Implantation.

OBJECTIVES: The purpose of this study was to determine whether the mitral valve (MV) total leaflet area (TLA)-to-mitral annular area (MAA) (TLA/MAA) ratio measured using 3-dimensional (3D) transesophageal echocardiography (TEE) was associated with residual mitral regurgitation (MR) after MitraClip implantation in patients with secondary MR. BACKGROUND: The factors influencing the results of MitraClip implantation for secondary MR are controversial. This study hypothesized that insufficient remodeling of the mitral leaflets relative to the annular dilation may be associated with significant MR after MitraClip implantation. METHODS: This study included patients with secondary MR treated with MitraClips. Using 3D TEE dataset, the TLA in diastole and MAA in systole were measured with dedicated software. RESULTS: In a total cohort of 119 patients (mean age 74 ± 9 years; 61% male), significant residual MR (≥2+) was present in 43 patients (36%). In patients with significant residual MR, MAA was greater than in patients without residual MR (10.7 ± 2.4 cm2 vs. 9.0 ± 2.1 cm2; p < 0.001) whereas no significant difference was observed in TLA (12.2 ± 2.6 cm2 vs. 12.0 ± 2.9 cm2; p = 0.836). TLA/MAA ratio was lower in patients with significant residual MR as compared to their counterparts (1.14 ± 0.15 vs. 1.34 ± 0.16; p < 0.001), suggesting insufficient leaflet remodeling relative to annular dilation. On receiver-operating characteristic curve analysis, the TLA/MAA ratio had better discriminative power to identify patients who will have significant residual MR compared to MAA alone (area under the curve [AUC]: 0.830 vs. 0.723; p = 0.049). CONCLUSIONS: In patients with secondary MR, insufficient mitral leaflet remodeling relative to the annulus dilation, as reflected by a lower TLA/MAA ratio, is associated with significant residual MR after MitraClip implantation.

Assessment of D-Shaped Annulus of Mitral Valve in Patients with Severe MR Using Semi-Automated 4-Dimensional Analysis: Implications for Transcatheter Interventions.

The development of transcatheter mitral valve replacement therapies requires accurate post-processing analysis tools to provide D-shaped mitral annulus dimensions from 3-dimensional (3D) data. The agreement between two semi-automated, software packages to process 3D transesophageal echocardiography (TEE) data for the measurement of the mitral valve annulus dimensions was evaluated. 3DTEE data of patients with moderate-severe mitral regurgitation (MR) were postprocessed with semi-automated, vendor-independent (VI) software and vendor-specific (VS) software. Both post-processing software provided key measurements for the selection of transcatheter valve prosthesis size: annulus area, annulus circumference and the septal-to-lateral distance of the annulus. The intertrigonal distance was provided only by the VS software. The inter- and intra-observer agreements were assessed with Bland-Altman analysis. Of 105 patients (63.8 ± 11 years, 66% male) with MR, 28 had secondary MR, 45 fibroelastic deficiency, and 32 Barlow's disease. Using VS software, the dimensions for the overall population were 16.1 ± 4.6 cm2 for annulus area, for circumference 14.4 ± 1.9 cm, intertrigonal distance 3.4 ± 0.5 cm and septal-to-lateral distance 3.8 ± 0.6 cm. Similar dimensions were obtained using VI software: 15.7 ± 4.6 cm2 for annulus area, 14.5 ± 2.0 cm for circumference, and 4.1 ± 0.6 cm for septal-to-lateral distance. The inter- and intra-observer agreement for both software programs was excellent. In conclusion, current post-processing software programs for 3DTEE data of the mitral valve annulus provide good reproducibility of key measurements to select the transcatheter prosthesis size.

Prognostic Implications of Significant Isolated Tricuspid Regurgitation in Patients With Atrial Fibrillation Without Left-Sided Heart Disease or Pulmonary Hypertension.

The prognostic impact of isolated tricuspid regurgitation (TR) in patients with atrial fibrillation (AF) has not been investigated. The purpose of this study was to investigate the prognostic implications of significant isolated TR in AF patients without left-sided heart disease, pulmonary hypertension, or primary structural abnormalities of the tricuspid valve. A total of 63 AF patients with moderate and severe TR were matched for age and gender to 116 AF patients without significant TR. Patients were followed for the occurrence of all-cause mortality, hospitalization for heart failure and stroke. Patients with significant isolated TR (mean age 71 ± 8 years, 57% men) more often had paroxysmal AF as compared with patients without TR (mean age 71 ± 7 years, 60% men) (60% vs 43%, p = 0.028). In addition, right atrial size and tricuspid annular diameter were significantly larger in patients with significant isolated TR compared with their counterparts. During follow-up (median 62 [34 to 95] months), 53 events for the combined endpoint occurred. One- and 5-year event-free survival rates for patients with significant isolated TR were 76% and 56%, compared with 92% and 85% for patients without significant TR, respectively (Log rank Chi-Square p <0.001). The presence of significant isolated TR was independently associated with the combined endpoint (hazard ratio, 2.853; 95% confidence interval, 1.458 to 5.584; p = 0.002). In conclusion, in the absence of left-sided heart disease and pulmonary hypertension, significant isolated TR is independently associated with worse event-free survival in patients with AF.

Imaging of the mitral valve: role of echocardiography, cardiac magnetic resonance, and cardiac computed tomography.

PURPOSE OF REVIEW: This article reviews the role of multimodality imaging in the in evaluation of patients with mitral regurgitation referred for transcatheter interventions. RECENT FINDINGS: Transcatheter therapies for mitral regurgitation in patients with high surgical risk or contraindications for surgery are evolving rapidly. Three-dimensional imaging techniques (transesophageal echocardiography, computed tomography, and cardiovascular magnetic resonance) are key to determine the anatomical suitability for each transcatheter therapy, to accurately quantify mitral regurgitation, and to plan and guide the procedure. Fusion imaging is being implemented in catheterization laboratories to precisely guide the procedure and to maximize safety and optimal results. Transcatheter edge-to-edge mitral valve repair with the MitraClip device (Abbott Vascular, Santa Clara, CA) provides the largest evidence on the safety and efficacy of this minimally invasive therapy and the importance of accurate patient selection to improve outcomes has been recently shown in two randomized trials. SUMMARY: Multimodality imaging is key in the work-up of patient with mitral regurgitation undergoing transcatheter therapies. Preprocedural imaging with three-dimensional echocardiography, computed tomography, and cardiac magnetic resonance is important to evaluate the eligibility of patients for transcatheter interventions, whilst three-dimensional transesophageal echocardiography provides soft-tissue information that can be overlaid onto fluoroscopy allowing more accurate guidance of transcatheter interventions.

Characteristics and Prognosis of Patients With Nonvalvular Atrial Fibrillation and Significant Valvular Heart Disease Referred for Electrical Cardioversion.

Valvular atrial fibrillation (AF) is defined as AF in the presence of mitral stenosis or mechanical valve prosthesis. However, there are patients with AF who have significant native valvular heart disease (VHD) others than mitral stenosis that are classified as nonvalvular AF. The characteristics and prognostic implications of these entities have not been extensively studied. Of 1,885 AF patients referred for electrical cardioversion (64 ± 13years, 71% male), 171 (9.1%) had valvular AF (any grade of mitral stenosis or mechanical/biological valve prostheses) and 1,714 patients were identified as nonvalvular AF, of whom 329 (17.5%) had significant left-sided VHD. Patients with nonvalvular AF but with significant left-sided VHD were older, more frequently women and had more co-morbidities compared with the other groups. Furthermore, nonvalvular AF patients with significant left-sided VHD showed the worst left ventricular systolic function and largest left atrial volumes. During a median follow-up of 64 months (interquartile range: 33 to 96 months), 488 patients presented with the combined endpoint of all-cause mortality, heart failure hospitalization, and ischemic stroke. Patients with nonvalvular AF and with significant left-sided VHD had more events of heart failure whereas patients with valvular AF had higher all-cause mortality events. There were no differences in ischemic stroke events. Type of AF was not associated with outcomes after correcting for echocardiographic variables. In conclusion, the frequency of AF patients with significant VHD is relatively high. The consequences of VHD and AF on cardiac structure and function are more important determinants of adverse outcome than the type of AF.

YAP/TAZ Regulate Elevation and Bone Formation of the Mouse Secondary Palate.

Clefting of the secondary palate is one of the most common congenital anomalies, and the multiple corrective surgeries that individuals with isolated cleft palate undergo are associated with major costs and morbidities. Secondary palate development is a complex, multistep process that includes the elevation of the palatal shelves from a vertical to horizontal position, a process that is not well understood. The Hippo signaling cascade is a mechanosensory pathway that regulates morphogenesis, homeostasis, and regeneration by controlling cell proliferation, apoptosis, and differentiation, primarily via negative regulation of the downstream effectors, Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ). We deleted Yap/Taz throughout the palatal shelf mesenchyme as well as specifically in the posterior palatal shelf mesenchyme, using the Osr2Cre and Col2Cre drivers, respectively, which resulted in palatal shelf elevation delay and clefting of the secondary palate. In addition, the deletion resulted in undersized bones of the secondary palate. We next determined downstream targets of YAP/TAZ in the posterior palatal shelves, which included Ibsp and Phex, genes involved in mineralization, and Loxl4, which encodes a lysyl oxidase that catalyzes collagen crosslinking. Ibsp, Phex, and Loxl4 were expressed at decreased levels in the ossification region in the posterior palatal shelf mesenchyme upon deletion of Yap/Taz. Furthermore, collagen levels were decreased specifically in the same region prior to elevation. Thus, our data suggest that YAP/TAZ may regulate collagen crosslinking in the palatal shelf mesenchyme, thus controlling palatal shelf elevation, as well as mineralization of the bones of the secondary palate.

I.CAN: health coaching provides tailored nutrition and physical activity guidance to people diagnosed with cancer in a rural region in West Gippsland, Australia.

PURPOSE: I.CAN is a program which uses health coaching to provide tailored nutrition and physical activity guidance to people diagnosed with cancer in a rural region in eastern Victoria, Australia. I.CAN builds patients' nutritional knowledge, attitudes and health literacy to healthy eating and weight maintenance and incorporates sustainable and affordable dietary changes into everyday eating patterns. While oncology care identifies patients at risk of malnutrition and weight loss, less attention has been placed on building patient's capacity for healthy lifestyles and behaviours after cancer treatment. METHODS: I.CAN is delivered by a dietitian and exercise physiologist and is offered in three streams, one-on-one consultation, one-one-one and group and group. Paired t tests and chi-square analysis were used to analyse data. RESULTS: At 3-month review, I.CAN participants (1) significantly increased exercise activity from 51 to 86% (p < 0.001) and (2) showed increased trends in positive food choices from 62 to 66%. Importantly, positive food choices for alcohol and processed snacks were maintained, and there were increases in positive food choices for fresh fruit and vegetables, low fat dairy and processed meats. CONCLUSION: I.CAN is an example of a program which can be delivered within a rural setting, with minimal resources, and achieve positive impact for patients. IMPLICATIONS FOR CANCER SURVIVORS: Key to the success of the program is promoting wellness early in the cancer trajectory and providing patients with practical tools, a person-centred and multidisciplinary team approach and a program which is adaptable to the changing needs of the patient and the health service.

Chronic migraine-cephalgia related to trigeminal artery: a case report of innovative regenerative approach.

Persistent trigeminal artery (PTA) originates from the posterior bend or lateral wall of the intra-cavernous carotid artery and is the most common occurring type of remnant primitive fetal arteries. In literature, there is limited number of reports on migraine-cephalgia (MC) associated with coexisting PTA. The primitive anastomose arteries that fully belong to the intracranial arterial vascular system are not supposed to perform any supportive functional activity; usually they are subjected to normal biological decay caused by the aging process and metabolic dysfunctions. The hypothesis suggests that these primitive fetal arteries such as PTA may not undergo a fast and structural deterioration but they might be active contributors to a series of mechanisms that can cause a variety of idiopathic complaints. Consequently this would bring a different therapeutic approach other than their surgical removal, which is the accepted option today as a solution for these problems. In this case report, a chronic unilateral MC due to coexisting PTA adjacent to trigeminal nerve is presented. The caliber and location of the PTA was confirmed by a CT-Angiography. The MC treatment was achieved by administration of bio-identical testosterone, human placenta extract (HPE), b-nicotinamide adenine dinucleotide (NADH) and low dose amlopidine.

Transabdominal Intrapericardial Approach in Liver Transplantation for Unresectable Primary Hepatic Functioning Paraganglioma With Invasion Into Hepatic Veins and Suprahepatic Vena Cava: A Surgical and Anesthesia Management Challenge.

Primary hepatic functional paraganglioma is a rare form of extra-adrenal catecholamine-secreting tumor. Definitive treatment of functioning paraganglioma is challenging because of the critical location of the tumor frequently in close proximity to vital structures and risk of excessive catecholamine release during operative manipulation. We report the multidisciplinary management approach for a case of unresectable primary hepatic functional paraganglioma with invasion into the hepatic veins and suprahepatic vena cava. To our knowledge, this is the first report showing that orthotopic liver transplantation is curative for patients with unresectable primary hepatic paraganglioma. For locally advanced unresectable hepatic paraganglioma that involves the intrapericardial vena cava, a meticulous pre- and intraoperative medical management and transabdominal intrapericardial vascular control of the suprahepatic vena cava during orthotopic liver transplantation allows for complete extirpation of the tumor and achieves optimal outcome.

Age-related declines in α-Klotho drive progenitor cell mitochondrial dysfunction and impaired muscle regeneration.

While young muscle is capable of restoring the original architecture of damaged myofibers, aged muscle displays a markedly reduced regeneration. We show that expression of the "anti-aging" protein, α-Klotho, is up-regulated within young injured muscle as a result of transient Klotho promoter demethylation. However, epigenetic control of the Klotho promoter is lost with aging. Genetic inhibition of α-Klotho in vivo disrupted muscle progenitor cell (MPC) lineage progression and impaired myofiber regeneration, revealing a critical role for α-Klotho in the regenerative cascade. Genetic silencing of Klotho in young MPCs drove mitochondrial DNA (mtDNA) damage and decreased cellular bioenergetics. Conversely, supplementation with α-Klotho restored mtDNA integrity and bioenergetics of aged MPCs to youthful levels in vitro and enhanced functional regeneration of aged muscle in vivo in a temporally-dependent manner. These studies identify a role for α-Klotho in the regulation of MPC mitochondrial function and implicate α-Klotho declines as a driver of impaired muscle regeneration with age.

Age-dependent changes in intervertebral disc cell mitochondria and bioenergetics.

Robust cellular bioenergetics is vital in the energy-demanding process of maintaining matrix homeostasis in the intervertebral disc. Age-related decline in disc cellular bioenergetics is hypothesised to contribute to the matrix homeostatic perturbation observed in intervertebral disc degeneration. The present study aimed to measure how ageing impacted disc cell mitochondria and bioenergetics. Age-related changes measured included matrix content and cellularity in disc tissue, as well as matrix synthesis, cell proliferation and senescence markers in cell cultures derived from annulus fibrosus (AF) and nucleus pulposus (NP) isolated from the discs of young (6-9 months) and older (36-50 months) New Zealand White rabbits. Cellular bioenergetic parameters were measured using a Seahorse XFe96 Analyzer, in addition to quantitating mitochondrial morphological changes and membrane potential. Ageing reduced mitochondrial number and membrane potential in both cell types. Also, it significantly reduced glycolytic capacity, mitochondrial reserve capacity, maximum aerobic capacity and non-glucose-dependent respiration in NP. Moreover, NP cells exhibited age-related decline in matrix synthesis and reduced cellularity in older tissues. Despite a lack of changes in mitochondrial respiration with age, AF cells showed an increase in glycolysis and altered matrix production. While previous studies report age-related matrix degenerative changes in disc cells, the present study revealed, for the first time, that ageing affected mitochondrial number and function, particularly in NP cells. Consequently, age-related bioenergetic changes may contribute to the functional alterations in aged NP cells that underlie disc degeneration.

Extracellular dsRNA induces a type I interferon response mediated via class A scavenger receptors in a novel Chinook salmon derived spleen cell line.

Despite increased global interest in Chinook salmon aquaculture, little is known of their viral immune defenses. This study describes the establishment and characterization of a continuous cell line derived from Chinook salmon spleen, CHSS, and its use in innate immune studies. Optimal growth was seen at 14-18 °C when grown in Leibovitz's L-15 media with 20% fetal bovine serum. DNA analyses confirmed that CHSS was Chinook salmon and genetically different from the only other available Chinook salmon cell line, CHSE-214. Unlike CHSE-214, CHSS could bind extracellular dsRNA, resulting in the rapid and robust expression of antiviral genes. Receptor/ligand blocking assays confirmed that class A scavenger receptors (SR-A) facilitated dsRNA binding and subsequent gene expression. Although both cell lines expressed three SR-A genes: SCARA3, SCARA4, and SCARA5, only CHSS appeared to have functional cell-surface SR-As for dsRNA. Collectively, CHSS is an excellent cell model to study dsRNA-mediated innate immunity in Chinook salmon.

Crystallisation in basaltic magmas revealed via in situ 4D synchrotron X-ray microtomography.

Magma crystallisation is a fundamental process driving eruptions and controlling the style of volcanic activity. Crystal nucleation delay, heterogeneous and homogeneous nucleation and crystal growth are all time-dependent processes, however, there is a paucity of real-time experimental data on crystal nucleation and growth kinetics, particularly at the beginning of crystallisation when conditions are far from equilibrium. Here, we reveal the first in situ 3D time-dependent observations of crystal nucleation and growth kinetics in a natural magma, reproducing the crystallisation occurring in real-time during a lava flow, by combining a bespoke high-temperature environmental cell with fast synchrotron X-ray microtomography. We find that both crystal nucleation and growth occur in pulses, with the first crystallisation wave producing a relatively low volume fraction of crystals and hence negligible influence on magma viscosity. This result explains why some lava flows cover kilometres in a few hours from eruption inception, highlighting the hazard posed by fast-moving lava flows. We use our observations to quantify disequilibrium crystallisation in basaltic magmas using an empirical model. Our results demonstrate the potential of in situ 3D time-dependent experiments and have fundamental implications for the rheological evolution of basaltic lava flows, aiding flow modelling, eruption forecasting and hazard management.

The effect of long-term bisphosphonate therapy on trabecular bone strength and microcrack density.

OBJECTIVES: Bisphosphonates (BP) are the first-line treatment for preventing fragility fractures. However, concern regarding their efficacy is growing because bisphosphonate is associated with over-suppression of remodelling and accumulation of microcracks. While dual-energy X-ray absorptiometry (DXA) scanning may show a gain in bone density, the impact of this class of drug on mechanical properties remains unclear. We therefore sought to quantify the mechanical strength of bone treated with BP (oral alendronate), and correlate data with the microarchitecture and density of microcracks in comparison with untreated controls. METHODS: Trabecular bone from hip fracture patients treated with BP (n = 10) was compared with naïve fractured (n = 14) and non-fractured controls (n = 6). Trabecular cores were synchrotron scanned and micro-CT scanned for microstructural analysis, including quantification of bone volume fraction, microarchitecture and microcracks. The specimens were then mechanically tested in compression. RESULTS: BP bone was 28% lower in strength than untreated hip fracture bone, and 48% lower in strength than non-fractured control bone (4.6 MPa vs 6.4 MPa vs 8.9 MPa). BP-treated bone had 24% more microcracks than naïve fractured bone and 51% more than non-fractured control (8.12/cm2vs 6.55/cm2vs 5.25/cm2). BP and naïve fracture bone exhibited similar trabecular microarchitecture, with significantly lower bone volume fraction and connectivity than non-fractured controls. CONCLUSION: BP therapy had no detectable mechanical benefit in the specimens examined. Instead, its use was associated with substantially reduced bone strength. This low strength may be due to the greater accumulation of microcracks and a lack of any discernible improvement in bone volume or microarchitecture. This preliminary study suggests that the clinical impact of BP-induced microcrack accumulation may be significant.Cite this article: A. Jin, J. Cobb, U. Hansen, R. Bhattacharya, C. Reinhard, N. Vo, R. Atwood, J. Li, A. Karunaratne, C. Wiles, R. Abel. The effect of long-term bisphosphonate therapy on trabecular bone strength and microcrack density. Bone Joint Res 2017;6:602-609. DOI: 10.1302/2046-3758.610.BJR-2016-0321.R1.

Development and use of an Arctic charr cell line to study antiviral responses at extremely low temperatures.

Arctic charr (Salvelinus alpinus) are the northernmost distributed freshwater fish and can grow at water temperatures as low as 0.2 °C. Other teleost species have impaired immune function at temperatures that Arctic charr thrive in, and thus, charr may maintain immune function at these temperatures. In this study, a fibroblastic cell line, named ACBA, derived from the bulbus arteriosus (BA) of Arctic charr was developed for use in immune studies at various temperatures. ACBA has undergone more than forty passages at 18 °C over 3 years, while showing no signs of senescence-associated ß-galactosidase activity and producing nitric oxide. Remarkably, ACBA cells survived and maintained some mitotic activity even at 1 °C for over 3 months. At these low temperatures, ACBA also continued to produce MH class I proteins. After challenge with poly I:C, only antiviral Mx proteins were induced while MH proteins remained constant. When exposed to live viruses, ACBA was shown to permit viral infection and replication of IPNV, VHSV IVa and CSV at 14 °C. Yet at the preferred temperature of 4 °C, only VHSV IVa was shown to replicate within ACBA. This study provides evidence that Arctic charr cells can maintain immune function while also resisting infection with intracellular pathogens at low temperatures.