Long-term outcomes of the mayo conservative hip system in patients aged 30 years or less with osteonecrosis of the femoral head: mean follow-up of more than 10 years

INTRODUCTION

Historically, total hip arthroplasty (THA) in very young patients has been associated with lower survivorship. However, the long-term outcomes of THA using short stems for osteonecrosis of the femoral head (ONFH) in very young patients remain unclear. Therefore, this study aimed to investigate the long-term outcomes of the Mayo conservative hip system, a short metaphyseal stabilised stem, in patients with ONFH aged ≦30 years.

MATERIALS AND METHODS

We retrospectively reviewed 104 joints in 76 patients with ONFH who underwent THA using the Mayo conservative hip system with a minimum follow-up of 8 years. The mean follow-up period was 12.5 (range, 8-19) years. Patients were categorised into two age groups (≦30 years, n = 21 and > 30 years, n = 83). Radiographic evaluation was used to assess stem sinking, stress shielding, and spot welds. The clinical evaluations were performed using the Japanese Orthopedic Association (JOA) hip score. Postoperative major complication and revision surgery rates were also assessed.

RESULTS

The patient characteristics were similar between the two groups, except for the age. Revision surgeries were performed in five cases, with similar implant survival rates between the groups. Dislocations occurred in the older age group alone (four joints). One case of intra-operative periprosthetic femoral fracture was found in the younger age group. Stem sinking of > 3 mm occurred in one and seven joints in the younger and older age groups, respectively. Spot welds were observed in most joints (93.2%) in modified Gruen zones 2 and 6 without significant differences between the groups. Stress shielding showed no significant differences in the frequency of occurrence or location between the two groups. Furthermore,the JOA score showed no significant difference between the two groups.

CONCLUSION

The use of short stems in patients aged ≤ 30 years with ONFH showed favourable long-term outcomes.

Niacin supplementation attenuates the regression of three-dimensional capillary architecture in unloaded female rat skeletal muscle

Inactivity can lead to muscle atrophy and capillary regression in skeletal muscle. Niacin (NA), known for inducing hypermetabolism, may help prevent this capillary regression. In this study involving adult female Sprague-Dawley rats, the animals were randomly assigned to one of four groups: control (CON), hindlimb unloading (HU), NA, and HU with NA supplementation (HU + NA). For a period of 2 weeks, the rats in the HU and HU + NA groups underwent HU, while those in the NA and HU + NA groups received NA (750 mg/kg) twice daily through oral administration. The results demonstrated that HU lowered capillary number, luminal diameter, and capillary volume, as well as decreased succinate dehydrogenase activity, slow fiber composition, and PGC-1α expression within the soleus muscle. However, NA supplementation prevented these alterations in capillary structure due to unloading by stimulating PGC-1α factors and inhibiting mitochondrial dysfunction. Therefore, NA supplementation could serve as a potential therapeutic approach for preserving the capillary network and mitochondrial metabolism of muscle fibers during periods of inactivity.

Time elapsed from definitive diagnosis to surgery for osteonecrosis of the femoral head: a nationwide observational study in Japan

OBJECTIVES

This study documents the time elapsed from the diagnosis of osteonecrosis of the femoral head (ONFH) to surgery, exploring the factors that influence ONFH severity.

DESIGN

Retrospective observational study of a nationwide database.

SETTING

The Kaplan-Meier method with log-rank tests was applied to examine the period from definitive diagnosis of ONFH to surgery using any surgery as the end point. For bilateral cases, the date of the first surgery was the endpoint.

PARTICIPANTS

This study included 2074 ONFH cases registered in 34 university hospitals and highly specialised hospitals of the multicentre sentinel monitoring system of the Japanese Investigation Committee between 1997 and 2018.

MAIN OUTCOME MEASURE

The primary outcome was the time from diagnosis to surgery. The secondary outcome was the proportion of subjects remaining without surgery at 3, 6 and 9 months, and at 1, 2 and 5 years after diagnosis.

RESULTS

The median time to surgery was 9 months (IQR 4-22 months) after diagnosis of ONFH. The time to surgery was significantly shorter in the alcohol alone group and the combined corticosteroid and alcohol group than in the corticosteroid alone group (p=0.018 and p<0.001, respectively), in early stage ONFH with no or mild joint destruction (stages II and III, p<0.001), and with joint preserving surgery (p<0.001). The proportion without surgery was 75.8% at 3 months, 59.6% at 6 months, 48.2% at 9 months, 40.5% at 1 year, 22.2% at 2 years and 8.3% at 5 years.

CONCLUSION

ONFH has been considered to be an intractable disease that often requires surgical treatment, but the fact that surgery was performed in more than half of the patients within 9 months from diagnosis suggests severe disease with a significant clinical impact.

TRIAL REGISTRATION NUMBER

Chiba University ID1049.

Effects of interleukin-15 on autophagy regulation in the skeletal muscle of mice

This study aimed to evaluate the role of skeletal muscle-derived interleukin (IL)-15 in the regulation of skeletal muscle autophagy using IL-15 knockout (KO) and transgenic (TG) mice. Male C57BL/6 wild-type (WT), IL-15 KO, and IL-15 TG mice were used in this study. Changes in muscle mass, forelimb grip strength, succinate dehydrogenase (SDH) activity, gene and protein expression levels of major regulators and indicators of autophagy, comprehensive gene expression, and DNA methylation in the gastrocnemius muscle were analyzed. Enrichment pathway analyses revealed that the pathology of IL-15 gene deficiency was related to the autophagosome pathway. Moreover, although IL-15 KO mice maintained gastrocnemius muscle mass, they exhibited a decrease in autophagy induction. IL-15 TG mice exhibited a decrease in gastrocnemius muscle mass and an increase in forelimb grip strength and SDH activity in skeletal muscle. In the gastrocnemius muscle, the ratio of phosphorylated adenosine monophosphate-activated protein kinase α (AMPKα) to total AMPKα and unc-51-like autophagy activating kinase 1 and Beclin1 protein expression were higher in the IL-15 TG group than in the WT group. IL-15 gene deficiency induces a decrease in autophagy induction. In contrast, IL-15 overexpression could improve muscle quality by activating autophagy induction while decreasing muscle mass. The regulation of IL-15 in autophagy in skeletal muscles may lead to the development of therapies for the autophagy-induced regulation of skeletal muscle mass and cellular quality control.NEW & NOTEWORTHY IL-15 gene deficiency can decrease autophagy induction. However, although IL-15 overexpression induced a decrease in muscle mass, it led to an improvement in muscle quality. Based on these results, understanding the role of IL-15 in regulating autophagy pathways within skeletal muscle may lead to the development of therapies for the autophagy-induced regulation of skeletal muscle mass and cellular quality control.

High Concentrations of Nucleotides Prevent Capillary Regression during Hindlimb Unloading by Inhibiting Oxidative Stress and Enhancing Mitochondrial Metabolism of Soleus Muscles in Rats

Prolonged inactivity in skeletal muscles decreases muscle capillary development because of an imbalance between pro- and antiangiogenic signals, mitochondrial metabolism disorders, and increased oxidative stress. Nucleotides have been shown to exert a dose-dependent effect on disuse-induced muscle atrophy. However, the dose-dependent effect on capillary regression in disused muscles remains unclear. Therefore, this study investigated the dose-dependent effect of nucleotides on capillary regression due to disuse. For this purpose, Wistar rats were divided into five groups as follows: control rats fed nucleotide-free diets (CON), hindlimb-unloaded rats fed nucleotide-free diets (HU), and hindlimb-unloaded rats fed 1.0%, 2.5%, and 5.0% nucleotide diets, (HU + 1.0% NT), (HU + 2.5% NT), and (HU + 5.0% NT), respectively. Unloading increased reactive oxygen species (ROS) production and decreased mitochondrial enzyme activity, thereby decreasing the number of muscle capillaries. In contrast, 5.0% nucleotide-containing diet prevented increases in ROS production and reductions in the expression levels of NAMPT, PGC-1α, and CPT-1b proteins. Moreover, 5.0% nucleotide-containing diet prevented mitochondrial enzyme activity (such as citrate synthase and beta-hydroxy acyl-CoA dehydrogenase activity) via NAMPT or following PGC-1α upregulation, thereby preventing capillary regression. Therefore, 5.0% nucleotide-containing diet is likely to prevent capillary regression by decreasing oxidative stress and increasing mitochondrial metabolism.

Alternating current electromagnetic field exposure lessens intramyocellular lipid accumulation due to high-fat feeding via enhanced lipid metabolism in mice

Long-term high-fat feeding results in intramyocellular lipid accumulation, leading to insulin resistance. Intramyocellular lipid accumulation is related to an energy imbalance between excess fat intake and fatty acid consumption. Alternating current electromagnetic field exposure has been shown to enhance mitochondrial metabolism in the liver and sperm. Therefore, we hypothesized that alternating current electromagnetic field exposure would ameliorate high-fat diet-induced intramyocellular lipid accumulation via activation of fatty acid consumption. C57BL/6J mice were either fed a normal diet (ND), a normal diet and exposed to an alternating current electromagnetic field (ND+EMF), a high-fat diet (HFD), or a high-fat diet and exposed to an alternating current electromagnetic field (HFD+EMF). Electromagnetic field exposure was administered 8 hrs/day for 16 weeks using an alternating current electromagnetic field device (max.180 mT, Hokoen, Utatsu, Japan). Tibialis anterior muscles were collected for measurement of intramyocellular lipids, AMPK phosphorylation, FAT/CD-36, and carnitine palmitoyltransferase (CPT)-1b protein expression levels. Intramyocellular lipid levels were lower in the HFD + EMF than in the HFD group. The levels of AMPK phosphorylation, FAT/CD-36, and CPT-1b protein levels were higher in the HFD + EMF than in the HFD group. These results indicate that alternating current electromagnetic field exposure decreases intramyocellular lipid accumulation via increased fat consumption.

High-degree posterior rotational osteotomy for extensive collapsed femoral head osteonecrosis in teenagers: remodeling and results with a mean of 10-year follow-up

INTRODUCTION

This study evaluated the effectiveness of high-degree posterior rotational osteotomy for teenagers with extensively collapsed femoral head osteonecrosis.

MATERIALS AND METHODS

We reviewed 40 hips in 35 patients with severely collapsed femoral head osteonecrosis treated by this procedure with a mean follow-up period of 9.7 years (range 5-25 years). Thirteen hips had a history of steroid administration. Nine had slipped capital femoral epiphysis. Nine had femoral neck fracture. Two had traumatic dislocation and fracture. Seven had no apparent risk factors. The mean age of the patients (18 women and 17 men) was 14.8 years. All femoral heads were extensively collapsed below the acetabular roof, and 20 hips showed preoperative joint space narrowing (ARCO stage 4). Lateral radiographs of the femoral head revealed extensive lesions from the posterior to anterior portion. The mean degree of posterior rotation was 118° with intentional varus positioning [mean: 19° (range 10-30)]. The pre- and postoperative extent of the viable area of the femoral head was assessed using conventional anteroposterior radiographs and 45-degree flexion radiography. Further collapse, joint space narrowing, femoral head morphology, and congruency with the acetabulum based on the Stulberg classification were assessed using conventional anteroposterior radiographs. The clinical assessment was conducted using the Merle d'Aubigné hip scores at the last follow-up.

RESULTS

The viable area of the femoral head on the loaded portion was seen during a short period after operations. The necrotic lesions were gradually improved postoperatively. The mean extent of viable bone below the acetabular roof was 48% at less than 6 months after surgery and 92% at the final follow-up. The mean extent on 45° flexion radiography was 54% at less than 6 months after surgery and 89% at the final follow-up. Further collapse was prevented in 38 hips (95%). In 19 of 20 hips with preoperative narrowing of the joint space, the joint space was first improved, but narrowing progressively observed in 9 of 40 hips at the final follow-up. Thirty-four hips had excellent or good clinical outcomes, whereas 6 had fair or poor outcomes.

CONCLUSIONS

We concluded that this procedure is effective at delaying the progression of degeneration if adequate area of viable bone can be moved under the loaded portion of the acetabulum in teenagers with severe femoral head osteonecrosis.

High-Degree Valgus Osteotomy for Severe Femoral Head Osteonecrosis After Femoral Neck Fracture with Nonunion: A Case Report

CASE

A 15-year-old adolescent boy had severe groin pain because of extensive osteonecrosis of the femoral head with collapse, joint space narrowing, and nonunion after a failed internal fixation for femoral neck fracture. We performed a 60° valgus osteotomy that moved the posteromedial small viable portion of the femoral head to the weight-bearing acetabular area. The femoral neck nonunion and the necrosis healed completely, and the spherical contour of the femoral head was regained after postoperative hip joint remodeling.

CONCLUSIONS

Good remodeling and congruency were achieved by performing high-degree valgus osteotomy to obtain sufficient viable area below the acetabular roof.

Mild Hyperbaric Oxygen Exposure Enhances Peripheral Circulatory Natural Killer Cells in Healthy Young Women

Mild hyperbaric oxygen (HBO) enhances oxygen absorption in blood, relieving fatigue without causing oxidative stress. The benefits of mild HBO have been recognized in the treatment of lifestyle-related diseases and hypertension, but no research has been conducted on its effects on immunity. The aim of the present study is to investigate the effect of mild HBO on natural killer (NK) cells and cytokines in healthy young women. This crossover randomized control trial was conducted with 16 healthy young women. Participants were randomly exposed to normobaric oxygen (NBO; 1.0 atmospheres absolute (ATA), 20.8% oxygen) and mild HBO conditions (1.4 ATA, 35-40% oxygen, injected 18L oxygen per minute) in a hyperbaric oxygen chamber for 70 min. Heart rate, parasympathetic activity, NK cell count, interleukin (IL)-6, IL-12p70 and derivatives of reactive oxygen metabolites (d-ROMs) were measured before and after both exposures. In the NBO condition, parasympathetic activity remained unchanged, whereas after mild HBO exposure, parasympathetic activity was significantly increased. NK cells remained unchanged after NBO exposure, while NK cells were increased after exposure to mild HBO. Exposure to mild HBO did not increase d-ROM values, IL-6 and IL-12p70 protein levels. These findings suggest that exposure to mild HBO can be a useful protocol to increase NK cells by regulating parasympathetic activity via increasing oxygen delivery.

Brazilian Propolis Intake Decreases Body Fat Mass and Oxidative Stress in Community-Dwelling Elderly Females: A Randomized Placebo-Controlled Trial

This study aimed to investigate the effects of Brazilian propolis on body fat mass and levels of adiponectin and reactive oxygen species among community-dwelling elderly females. This was a double-blind randomized placebo-controlled trial. Altogether, 78 females aged 66-84 years were randomly assigned to the propolis (PRO; n = 39) or placebo (PLA; n = 39) group. For 12 weeks, the PRO group were given three capsules containing 227 mg of propolis twice a day. Meanwhile, the PLA group were given daily placebo capsules. Of 78 participants, 53 (PLA group: n = 28, PRO group: n = 25) completed the study. Although no changes were observed in absolute or relative fat mass in the PLA group, they showed a significant decline in the PRO group. The level of serum adiponectin in the PLA group did not change, although that of the PRO group significantly increased. The level of d-ROMs in the PLA group significantly increased, whereas that of the PRO group significantly decreased. The serum SOD activity in the PLA group significantly decreased, whereas that of the PRO group tended to increase. These results suggest that propolis supplementation may decrease body fat mass and oxidative stress among community-dwelling elderly females.

Impacts of Astaxanthin Supplementation on Walking Capacity by Reducing Oxidative Stress in Nursing Home Residents

Oxidative stress is associated with deterioration of endurance and muscle strength, which are mostly accompanied by aging. Astaxanthin supplement has excellent antioxidant activity without any pro-oxidative properties. In this study, we investigated how astaxanthin supplementation affects walking endurance and muscle strength in nursing home residents. Healthy elderly individuals (age: 67 to 94) were divided into two groups: 13 subjects received a daily dose of 24 mg of astaxanthin for 16 weeks (astaxanthin group) and 11 subjects received a placebo (placebo group). These subjects were compared using body component measurements, serum d-ROM levels, the distance of 6-min walking, blood lactate levels after the 6-min walking test, and muscle strength. After supplementation, the levels of d-ROMs and blood lactate after the 6-min walking test in the astaxanthin group significantly decreased compared with the placebo group (p < 0.05). Additionally, the walking distance was significantly higher in the astaxanthin group than in the placebo group (p < 0.05), despite a significant reduction in lactate levels after 6-MWT (p < 0.05). However, no significant intergroup differences were observed in muscle mass and strength. Astaxanthin supplement for 16 weeks is effective to increase the endurance capacity of the elderly. Astaxanthin supplement suppresses d-ROMs at rest and lactic acid production after the 6-min walk test. In contrast, astaxanthin supplement did not show significant intergroup differences in the muscle mass and strength. Therefore, the effect was most likely accompanied by an increase in endurance instead of an increase in muscle strength.

Usefulness of the synthesized 18-lead ECG in identify the origin of premature ventricular contractions

Background

There are have been reports on the 12-lead ECG waveforms used to identify ventricular premature contractions (VPCs), but there are not enough algorithms. On the other hand, the synthesized 18-lead ECG adds the right-side chest leads (V3R, V4R, and V5R) and back leads (V7, V8, and V9) to the 12-lead ECG.

Purpose

This aim of this study was to evaluate whether the waveforms of the 18-lead ECG are useful in predicting the origin of VPCs.

Methods

We studied 86 consecutive patients (age :61.8±16.0 years, male: 54.5%) enrolled from multicenter who underwent radiofrequency catheter ablation for VPCs. We retrospectively investigated the association between origin of the VPCs and characteristics of the synthetic 18-leads ECG.

Results

The 18-lead ECG showed a specific pattern for the VPC originating near the His-bundle. In 17 cases, the QRS morphology in V5R exhibited a QS pattern, and 13 of 17 cases had VPCs originating near the His-bundle. In the other 69 cases, V5R did not exhibit a QS pattern. ROC curve analysis showed that the QS pattern in V5R predicted VPC originating near the His-bundle with high accuracy: sensitivity 100.0%, specificity 94.5%, and AUC 0.98. Furthermore, the positive predictive value was 76.5% and negative predictive value 100.0%.

Conclusion

The QS pattern shown in V5R of the 18-lead ECG was a useful parameter for identifying VPCs originating near the His-bundle, which might be a good reference indicator during radiofrequency catheter ablation for VPCs.

Funding Acknowledgement

Type of funding sources: None.

Direct Probe of the Ferromagnetic Proximity Effect at the Interface of SnTe/Fe Heterostructure by Polarized Neutron Reflectometry

Introducing magnetic order into a topological insulator (TI) system has attracted much attention with an expectation of realizing exotic phenomena such as the quantum anomalous Hall effect (QAHE) and axion insulator states. The magnetic proximity effect (MPE) is one of the promising schemes to induce the magnetic order on the surface of a TI without introducing disorder accompanied by doping magnetic impurities in the TI. In this study, we investigate the MPE at the interface of a heterostructure consisting of the topological crystalline insulator (TCI) SnTe and Fe by employing polarized neutron reflectometry. The ferromagnetic order penetrates ∼2.2 nm deep into the SnTe layer from the interface with Fe, which persists up to room temperature. This is induced by the MPE on the surface of the TCI preserving the coherent topological states without introducing the disorder by doping magnetic impurities. This would open up a way for realizing next-generation spintronics and quantum computational devices.

Soft-Magnetic Skyrmions Induced by Surface-State Coupling in an Intrinsic Ferromagnetic Topological Insulator Sandwich Structure

A magnetic skyrmion induced on a ferromagnetic topological insulator (TI) is a real-space manifestation of the chiral spin texture in the momentum space and can be a carrier for information processing by manipulating it in tailored structures. Here, a sandwich structure containing two layers of a self-assembled ferromagnetic septuple-layer TI, Mn(Bi_1-xSb_x)₂Te₄ (MnBST), separated by quintuple layers of TI, (Bi_1-xSb_x)₂Te₃ (BST), is fabricated and skyrmions are observed through the topological Hall effect in an intrinsic magnetic topological insulator for the first time. The thickness of BST spacer layer is crucial in controlling the coupling between the gapped topological surface states in the two MnBST layers to stabilize the skyrmion formation. The homogeneous, highly ordered arrangement of the Mn atoms in the septuple-layer MnBST leads to a strong exchange interaction therein, which makes the skyrmions "soft magnetic". This would open an avenue toward a topologically robust rewritable magnetic memory.

Effects of porous tantalum on periprosthetic bone remodeling around metaphyseal filling femoral stem: a multicenter, prospective, randomized controlled study

Periprosthetic bone loss due to adaptive bone remodeling is an important unresolved issue in cementless total hip arthroplasty (THA). The use of porous tantalum on the proximal surface of the femoral stem is expected to decrease postoperative bone loss around the prosthesis through early fixation. We conducted a multicenter randomized controlled study to determine if porous tantalum could reduce periprosthetic bone loss after THA. From October 2012 to September 2014, 118 patients (mean age, 61.5 years; 107 females and 11 males) were prospectively enrolled and were randomly allocated at a ratio of 1:1 to either a metaphyseal filling stem with a proximal porous tantalum coating (Trabecular Metal) or a conventional metaphyseal filling stem with fiber mesh coating (VerSys). Patients underwent dual-energy x-ray absorptiometry scans within 1 week after surgery (baseline) and at 6, 12, and 24 months after surgery to assess periprosthetic bone mineral density (BMD) in the 7 Gruen zones. In addition, the Japanese Orthopaedic Association hip score was assessed before surgery and at 6, 12, and 24 months after surgery. In the proximal periprosthetic region (zones 1 and 7), the Trabecular Metal group had significantly smaller reductions in BMD than the VerSys group throughout the study period. In the VerSys group, significant reductions in BMD compared to baseline were seen at each measurement point in all regions, except in zone 6 at 24 months. In the Trabecular Metal group, no significant reductions in BMD relative to baseline were seen in zones 1, 5, or 6 throughout the study period. Both groups demonstrated similar improvement in Japanese Orthopaedic Association hip scores over the study period. This study demonstrated that a proximally coated stem with porous tantalum has superior results over a conventional stem with titanium fiber mesh in terms of periprosthetic bone remodeling.

Protective effects of chlorogenic acid on capillary regression caused by disuse muscle atrophy

Inactivity causes muscle atrophy and capillary regression in skeletal muscle. Chlorogenic acid has an antioxidant capacity and may prevent capillary regression. Therefore, the protective effects of chlorogenic acid on inactivity-induced capillary regression in rat soleus muscle were investigated. Twenty male Wistar rats were randomly divided into four groups: control (CON), chlorogenic acid supplementation (CGA), 2-week hindlimb unloading (HU), 2-week hindlimb unloading plus chlorogenic acid supplementation (HU+CGA). The rats in CGA and HU+CGA groups were orally administrated chlorogenic acid (850 mg/kg/day). Unloading resulted in a decrease in capillary number, oxidative capacity, and an increase in oxidative stress of the soleus muscle, whereas chlorogenic acid supplementation prevented capillary and metabolic changes resulting from unloading by reducing oxidative stress. In conclusion, chlorogenic acid supplementation may qualify as an effective treatment to reduce capillary regression in skeletal muscle caused by disuse muscle atrophy.

Effect of diabetes mellitus on coronary plaque characteristics and progression by serial Coronary Computed Tomography Angiography (CCTA)

Background

Diabetes Mellitus (DM) is a major risk factor for coronary artery disease (CAD) and associated poor outcomes. There is a higher incidence of major adverse cardiac events in patients with DM than those without DM. Coronary plaque characteristics measured by CCTA are correlated with adverse cardiovascular (CV) outcomes.

Purpose

We sought to evaluate coronary plaque characteristics as well as rates of progression of coronary plaque burden as measured by serial CCTA in patients with DM and those without DM.

Methods

The study population included a total of 403 participants (mean age 61.4±11.4 years, 53% men; median scan interval 1.5 years) who were prospectively enrolled in serial CCTA trials. We identified 212 participants with DM and 191 participants without DM, who had undergone serial CCTA. Coronary Plaque volumes were measured and characterized as low attenuation plaque (LAP), total non-calcified plaque (TNCP) and total plaque (TP) using semi-automated plaque analysis software (Qangio medis). Multivariate linear regression was used to examine the effect of DM on coronary plaque progression.

Results

Patients with DM had greater rates of progression of normalized TP volume (median change in annualized plaque (IQR): 39.1 (9.9–114.4) in DM vs 23.5 (4.1–63.8) mm3 in non-DM, p=0.001), TNCP volume (21.6 (3.3–60.8) in DM vs 8.7 (0.1–35.6) mm3 in non-DM, p=0.003) and LAP volumes (0.7 (−0.6 to 7.8) in DM vs 0.1 (−0.4 to 1.9) mm3 in non-DM, p=0.04). After adjusting for relevant risk factors and baseline plaque, the annualized rates of progression were higher in patients with DM by 28% for TP (p=0.004), 27% for TNCP (p=0.011), 23% for fibrous plaque (p=0.026) and by 42% LAP (p=0.050), compared to those without DM.

Conclusion

Patients with DM have significantly higher rates of coronary plaque progression, including vulnerable LAP, than those without DM. Our findings reveal differences in rates, burden and characteristics of coronary plaque progression in patients with DM vs those without DM. These results provide mechanistic understanding of natural history of coronary atherosclerosis in this vulnerable population, that could explain the increased risk of CV events among patients with DM. Coronary atherosclerotic phenotyping by CCTA could serve as a potential surrogate measure for risk stratification and evaluation in clinical trials to examine therapeutic strategies in this vulnerable population.

Funding Acknowledgement

Type of funding sources: None.

Significance of mitral L wave to predict late recurrence of atrial fibrillation after radiofrequency catheter ablation

Background

Mitral L wave, prominent mid-diastolic filling wave in echocardiographic examinations, is associated with severe left ventricular diastolic dysfunction, and that has been reported to predict recurrent atrial fibrillation (AF) after cardioversion. However, association between mitral L wave and the outcome of AF after radiofrequency catheter ablation (RFCA) has not been established.

Objective

The aim of this study is to evaluate the predictive value of mitral L wave on AF recurrence after RFCA.

Methods

250 patients including 164 paroxysmal AF (65.6%) and 86 non-paroxysmal AF (34.4%) who received RFCA in single center from January 2015 to December 2016 were enrolled consecutively. Echocardiographic examinations before RFCA were recorded, and the mitral L wave was defined as a distinct mid-diastolic flow velocity with a peak velocity ≥20 cm/s following the E wave. Systematic follow-up was conducted after RFCA. Univariate and multivariate analyses were carried out to determine the factors predicting late recurrence of AF (LRAF) which means AF recurrence after 3 months. Enrolled patients were divided into groups with the L wave (L-group; n=57) or without the L wave (NL-group; n=193) based on the findings of echocardiographic examinations.

Results

During a follow-up of 35.0±17.6 months, the ratio of LRAF in the L-group was significantly higher than that in the NL-group (32 (56.1%) vs. 41 (21.2%), Hazard ratio [HR]: 3.55, 95% confidence interval [CI]: 2.33 - 5.42, p&lt;0.001). Among the clinical factors, presence of mitral L wave, BNP value, non-paroxysmal AF and moderate-severe mitral regurgitation were related to LRAF. A multivariate analysis using a Cox proportional hazard model found that presence of mitral L wave (HR: 2.67, 95% CI: 1.30 - 5.48, p=0.007) was significantly associated with LRAF.

Conclusion

This study revealed that mitral L wave predicts late recurrence of AF after RFCA.

Funding Acknowledgement

Type of funding sources: None.

Effects of combined treatment with blood flow restriction and low-current electrical stimulation on capillary regression in the soleus muscle of diabetic rats

To clarify the preventive effects of low-current electrical stimulation (ES) under blood flow restriction (Bfr) on diabetes-associated capillary regression in skeletal muscles, we assessed the changes in three-dimensional capillary architecture and angiogenic factors. Twenty-four Goto-Kakizaki rats were randomly divided into four groups: the sedentary diabetes mellitus (DM), Bfr (DM + Bfr), electrical stimulation (DM + ES), and Bfr plus ES (DM + Bfr + ES) groups. Six healthy Wistar rats were used as age-matched controls. Bfr was performed using pressure cuffs (80 mmHg) around the thighs of the rats, and low-current ES was applied to the calf muscles of the rats. The current intensity was set at 30% of the maximal isometric contraction (24-30 mA). The treatments were delivered three times a week for 8 wk. In the DM group, the capillary diameter and volume of the soleus muscle decreased, and, the antiangiogenic factor level increased. Furthermore, DM caused an increase in the hypoxia-inducible factor. Individually, Bfr or ES treatments failed to inhibit the DM-associated capillary regression and increase in antiangiogenic factor. However, combined treatment with Bfr and ES prevented DM-associated capillary regression via inhibition of the increased antiangiogenic factor and enhancement of interleukin-15 expression, mitochondrial biogenesis factors, and a proangiogenic factor. Therefore, DM-associated capillary regression inhibited by the combined treatment may prevent the effects of the increased antiangiogenic factor and enhance the proangiogenic factor.NEW & NOTEWORTHY The combined treatment of blood flow restriction and low intensity electrical stimulation attenuated type 2 diabetes (T2D)-associated capillary regression in the skeletal muscles. The treatment inhibits the T2D-associated increase in antiangiogenic factors via inhibition of intramuscular chronic hypoxia; it can inhibit intramuscular chronic hypoxia by enhancing proangiogenic factors. These results suggest that the combined treatment may be an effective therapeutic intervention for the prevention of T2D-associated capillary regression in the skeletal muscles.

Protective effects of Enterococcus faecium strain R30 supplementation on decreased muscle endurance under disuse in rats

NEW FINDINGS

What is the central question of this study? Does Enterococcus faecium strain R30 (R30), a new lactic acid bacterial strain for supplementation, attenuate shifts in the typology of whole muscle fibres from slow- to fast-twitch by altering the autonomic nervous system in atrophied skeletal muscles? What is the main finding and its importance? R30 supplementation may attenuate the shifts in the typology of whole muscle fibres from slow- to fast-twitch fibres by upregulating peroxisome proliferator-activated receptor-γ coactivator-1α and activating the calcineurin-nuclear factor of activated T-cells signalling pathway, thus ameliorating the decrease in muscle endurance associated with disuse.

ABSTRACT

Enterococcus faecium strain R30 (R30), a new lactic acid bacterial strain for supplementation, was hypothesized to attenuate shifts in the typology of whole muscle fibres from slow- to fast-twitch fibres in atrophied skeletal muscles. We further postulated that the prevention of slow-to-fast fibre shifts would suppress the decreased muscle endurance associated with atrophy. To evaluate the protective effects of R30, we analysed slow-to-fast fibre shifts and disuse-associated reduced muscle endurance. R30 was administered to rats with an acclimation period of 7 days before hindlimb unloading (HU) for 2 weeks. The composition ratio of the fibre type and the expression levels of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), calcineurin and nuclear factor of activated T-cells (NFAT) were measured. Muscle endurance was evaluated at the end of the 2-week HU period in an in situ environment. R30 supplementation suppressed the slow-to-fast fibre switch and decreased the HU-induced expression of PGC-1α proteins and the deactivation of the calcineurin-NFAT pathway. Furthermore, R30 prevented a decrease in HU-associated muscle endurance in calf muscles. These results indicate that R30 supplementation may attenuate the shifts in the typology of whole muscle fibres from slow- to fast-twitch fibres via the upregulation of PGC-1α and the activation of the calcineurin-NFAT signalling pathway, thereby ameliorating the decrease in muscle endurance associated with disuse.

Nucleoprotein-enriched diet enhances protein synthesis pathway and satellite cell activation via ERK1/2 phosphorylation in unloaded rat muscles

NEW FINDINGS

What is the central question of this study? The purpose of this study was to determine whether the nucleotides in a nucleoprotein-enriched diet could ameliorate the unloading-associated decrease in soleus muscle mass and fibre size. What is the main finding and its importance? The results indicate that the nucleotides in the nucleoprotein-enriched diet could ameliorate the unloading-associated decrease in type I fibre size and muscle mass, most probably owing to the activation of protein synthesis pathways and satellite cell proliferation and differentiation via ERK1/2 phosphorylation. Thus, nucleotide supplementation appears to be an effective countermeasure for muscle atrophy.

ABSTRACT

Hindlimb unloading decreases both the protein synthesis pathway and satellite cell activation and results in muscle atrophy. Nucleotides are included in nucleoprotein and provide the benefits of increasing extracellular signal-regulated kinase (ERK) 1/2 phosphorylation. ERK1/2 phosphorylation is also important in the activation of satellite cells, especially for myoblast proliferation and stimulating protein synthesis pathways. Therefore, we hypothesized that nucleotides in the nucleoproteins would ameliorate muscle atrophy by increasing the protein synthesis pathways and satellite cell activation during hindlimb unloading in rat soleus muscle. Twenty-four female Wistar rats were divided into four groups: control rats fed a basal diet without nucleoprotein (CON), control rats fed a nucleoprotein-enriched diet (CON+NP), hindlimb-unloaded rats fed a basal diet (HU) or hindlimb-unloaded rats fed a nucleoprotein-enriched diet (HU+NP). HU for 2 weeks resulted in reductions in phosphorylation of p70S6K and rpS6, the numbers of myoblast determination protein (MyoD)- and myogenin- positive nuclei, type I muscle fibre size and muscle mass. Both CON+NP and HU+NP rats showed an increase in ERK1/2, phosphorylation of p70S6K and rpS6, and the numbers of MyoD- and myogenin-positive nuclei compared with their basal diet groups. The NP diet also ameliorated the unloading-associated decrease in type I muscle fibre size and muscle mass. The results indicate that the nucleotides in the nucleoprotein-enriched diet could ameliorate the unloading-associated decrease in type I fibre size and muscle mass, most probably owing to the activation of protein synthesis pathways and satellite cell proliferation and differentiation via ERK1/2 phosphorylation. Thus, nucleotide supplementation appears to be an effective countermeasure for muscle atrophy.

Reduced metabolic capacity in fast and slow skeletal muscle via oxidative stress and the energy-sensing of AMPK/SIRT1 in malnutrition

The effects of malnutrition on skeletal muscle result in not only the loss of muscle mass but also fatigue intolerance. It remains unknown whether the metabolic capacity is related to the fiber type composition of skeletal muscle under malnourished condition although malnutrition resulted in preferential atrophy in fast muscle. The purpose of the present study was to investigate the effects of metabolic capacity in fast and slow muscles via the energy-sensing of AMPK and SIRT1 in malnutrition. Wistar rats were randomly divided into control and malnutrition groups. The rats in the malnutrition group were provided with a low-protein diet, and daily food intake was limited to 50% for 12 weeks. Malnutrition with hypoalbuminemia decreased the body weight and induced the loss of plantaris muscle mass, but there was little change in the soleus muscle. An increase in the superoxide level in the plasma and a decrease in SOD-2 protein expression in both muscles were observed in the malnutrition group. In addition, the expression level of AMPK in the malnutrition group increased in both muscles. Conversely, the expression level of SIRT1 decreased in both muscles of the malnutrition group. In addition, malnutrition resulted in a decrease in the expression levels of PGC-1α and PINK protein, and induced a decrease in the levels of two key mitochondrial enzymes (succinate dehydrogenase and citrate synthase) and COX IV protein expression in both muscles. These results indicate that malnutrition impaired the metabolic capacity in both fast and slow muscles via AMPK-independent SIRT1 inhibition induced by increased oxidative stress.

The effect of neuromuscular electrical stimulation on muscle EMG activity and the initial phase rate of force development during tetanic contractions in the knee extensor muscles of healthy adult males

OBJECTIVE

Neuromuscular electrical stimulation (NMES) has been noted as an effective pre- contraction for an increase of neural and muscle factors during twitch contractions. However, it is unknown if this intervention is effective for the rate of force development (RFD), which is the ability to increase joint torque strength as quickly as possible, during tetanic contractions. NMES can be safely used by anyone, but, the strength setting of NMES requires attention so as not to cause pain. Therefore, the purpose of this study investigated whether NMES at less painful levels was effective for RFD during tetanic contractions. We also investigated effect activation by analyzing electromyogram (EMG) and RFD for each phase.

METHODS

Eighteen healthy males were studied. Before and after NMES intervention at 10% or 20% maximal voluntary isometric contraction (MVIC) level (10%NMES, 20%NMES respectively), EMG activity and the initial phase (30-, 50-, 100-, and 200-msec) RFD were measured. Visual analog scale (VAS) was also measured as an indicator of pain during each NMES.

RESULTS

20%NMES increased EMG activity and 30-, 50-, and 100-msec of RFD during MVIC, but could not improve 200 msec of RFD. However, 10%NMES could be failed to increase all phases RFD, but VAS was lower than that of 20% NMES.

CONCLUSION

These results suggest that muscle pre-contraction using 20%NMES could induce moderate pain, but could be an effective intervention to improve RFD via neural factor activity.

Preventive effects of low-intensity endurance exercise for severe hyperglycemia-induced capillary regression in non-obese type 2 diabetes rat skeletal muscle

Although endurance exercise is effective for reducing diabetes‐related capillary regression, it is difficult to prescribe high‐intensity endurance exercise due to the potential worsening of complications in patients with severe hyperglycemia. Therefore, this study aimed to examine whether chronic low‐intensity exercise training may prevent severe hyperglycemia‐induced capillary regression of skeletal muscle in non‐obese type 2 diabetes. Non‐diabetic Sprague Dawley rats were assigned to a control (Con) group and an exercise (Ex) group. Likewise, spontaneously diabetic Torii rats were assigned to a diabetic sedentary (DM) group or a diabetic exercise (DMEx) group. Rats in the Ex and DMEx groups were placed on a motor‐driven treadmill running at low speed (15 m/min) for 60 min/day, 5 days/week, for 14 weeks. Serum glucose levels were significantly increased in the DM group, but not in the DMEx group. Although the capillary‐to‐fiber ratio in the plantaris muscle was significantly lower in the DM group compared to the control group, the ratio in the DMEx group was significantly higher compared to the DM group. Moreover, the succinate dehydrogenase activity and expression levels of vascular endothelial growth factor and peroxisome proliferator‐activated receptor γ coactivator‐1α (PGC‐1α) were reduced in the plantaris muscle of the DM group. However, those in the DMEx group were significantly higher than those in the DM group. These results indicate that low‐intensity chronic endurance exercise training has the potential to prevent the progression of capillary regression in the skeletal muscles of non‐obese type 2 diabetes patients with severe hyperglycemia.

Clinical usefulness of Lipoprotein(a) for the prevalence and severity of peripheral artery disease among patients with acute coronary syndrome

Background

Lipoprotein(a) [LP(a)] is known to be a robust lipid marker associated with cardiovascular events. Though coronary artery disease and peripheral artery disease (PAD) are often coexist, little is known about the relationship between LP(a) and PAD among patients with acute coronary syndrome (ACS).

Purpose

The purpose of this study is to examine if LP(a) is of predictive value for PAD among ACS patients in Japanese population.

Methods

Of consecutive 238 ACS patient who received successful primary PCI, a total of 175 patients were enrolled in the current study. We excluded the patients who received hemodialysis (n=10), required multidisciplinary treatment (n=36) and incomplete data (n=17). PAD was diagnosed as ankle brachial index &lt;0.9. Multiple lipid biomarkers [LP(a), low-density lipoprotein (LDL-C), high-density lipoprotein (HDL-C), malondialdehyde-modified LDL (MDA-LDL), docosahexaenoic acid and arachidonic acid] were compared between patients with PAD (n=21) and without PAD (n=154). Further, multivariable logistic regression models were used to assess if LP(a) was associated with PAD. In addition, serum LP(a) level were compared between 3 groups according to pattern of PAD [none (n=154), unilateral (n=10) and bilateral PAD (n=11), respectively].

Results

Compared to patients without PAD, those with PAD were older (74.4 vs. 65.4 years, p=0.003), and had a higher prevalence of chronic kidney disease (CKD) (61.9% vs. 20.1%, p&lt;0.001), diabetes mellitus (DM) (66.7% vs. 27.3%, p&lt;0.001). Serum LP(a) level was significantly higher in patients with PAD (36.4 vs. 18.5 mg/dl, p&lt;0.001), whereas LDL-C and MDA-LDL were significantly lower in PAD (92.0 vs. 109.5 mg/dl, p=0.015 and 98.6 vs. 119.5 mg/dl, p=0.046, respectively). After adjusting for LDL-C and MDA-LDL, LP(a) &gt;30 mg/dl was independently associated with a presence of PAD (OR 5.67, 95% CI 2.09–15.4, p=0.0006). When adjusting for CKD and DM in a different model, LP(a) &gt;30 mg/dl was similarly associated with PAD (OR 4.98, 95% CI 1.66–14.9, p=0.004). Serum LP(a) levels were significantly higher in bilateral PAD group compared to none PAD group (Figure).

Conclusion

LP(a) was a useful lipid biomarker for the prevalence and severity of PAD among patients with ACS in Japanese population.

Funding Acknowledgement

Type of funding source: None

Acute effects of lactic acid-fermented and enzyme-digested soybean on protein synthesis via mTOR signaling in the skeletal muscle

Protein-containing nutrients result in the efficient hypertrophy of muscles by increasing muscle protein synthesis. Soybean is often ingested by athletes or individuals who exercise; however, it takes very long to be absorbed. Lactic acid-fermented and enzyme-digested (LFED) soybean is absorbed faster than untreated soybean. This study aims at determining muscle protein synthesis after ingesting a single bolus of soybean or LFED soybean produced by lactic acid bacteria and protease digestion. Eight-week-old overnight-fasted ICR mice were administered powdered or LFED soybean. Mice were euthanized at 7, 15, 30, 60, 90, and 120 min after soybean intake. We have demonstrated that LFED soybean administration was quicker in stimulating muscle protein synthesis by activating mammalian target of rapamycin (mTOR) signaling than orally ingesting untreated soybean in the gastrocnemius muscle. These results suggested that LFED soybean is a more efficient source of nutrition for muscle hypertrophy than untreated soybean.

Effect of exercise therapy combined with branched-chain amino acid supplementation on muscle strength in elderly women after total hip arthroplasty: a randomized controlled trial

BACKGROUND AND OBJECTIVES

Many patients develop a prolonged decrease of muscle strength after total hip arthroplasty (THA) despite their reconstructed hip joint. Physical exercise combined with branched-chain amino acid (BCAA) supplementation has been reported to improve muscle strength in elderly persons with sarcopenia. However, the effect of BCAA supplementation in patients after THA is unknown. This study examined the effects of BCAA supplementation combined with exercise therapy on the improvement of physical function in elderly patients after THA.

METHODS AND STUDY DESIGN

The subjects were 31 elderly women who underwent THA. The participants were randomly assigned to two groups: BCAA (n=18) and control (n=13). The combined therapy was carried out for one month after THA. For the exercise intervention, a 3-set physical exercise program was conducted. For the nutritional intervention, the participants consumed 3.4 g of BCAA supplement or 1.2 g of starch immediately after the exercise intervention.

RESULTS

BCAA supplementation combined with muscle strengthening exercises had a significant effect on knee extension strength of the contralateral side and on upper arm cross-sectional area. The improvement ratio of knee extension strength before and after intervention on the operated side was also significantly higher in the BCAA group.

CONCLUSIONS

BCAA supplementation is effective for patients to improve the strength of some muscles when combined with physical exercises, but hip abductor muscle strength of the operated leg did not improve. A future study is needed to determine the efficacy of this combined therapy for hip abductor muscle strength.

P175 Prognostic value of 99mTc-ECD brain perfusion SPECT in patients with atrial fibrillation and dementia

Background

Atrial fibrillation (AF) is the most common cardiac arrhythmia, and those afflicted have reduced quality of life, functional status, and cardiac performance. The patients with AF have a high risk of coronary heart disease and cardiovascular disease. Although the prevalence of AF is increasing, cognitive disorders are also on the rise in tandem with the aging of the population. The patients with dementia have also experienced lower the quality of life and have increased mortality. Technetium 99m ECD brain perfusion single photon emission computed tomography (99mTc-ECD brain perfusion SPECT) is a useful modality for diagnosing dementia and identifying high risk patients with mild cognitive impairment. However, there are few reports about the relationship between the value of Z score calculated by 99mTc-ECD brain perfusion SPECT and prognosis of patients with AF and dementia.

Purpose

The aim of this study was to evaluate the prognostic values of brain perfusion using 99mTc-ECD SPECT in patients with AF and dementia.

Methods

Among 405 consecutive patients who were diagnosed as AF in cardiac outpatients and subsequently diagnosed as dementia using Mini-Mental State Examination by neurologists or psychiatrists, we identified 170 patients (81 ± 10 years) who underwent 99mTc-ECD brain perfusion SPECT for the current study. Of those, 73, 73, and 24 were diagnosed as Alzheimer’s dementia (AD), vascular dementia (VD), and non-specified dementia respectively. Multivariate Cox model was used to assess if higher Z score by 99mTc-ECD brain perfusion SPECT and clinical parameters were associated with major adverse cardiovascular events (MACE) including cardiac death, myocardial infarction, hospitalization for heart failure, and stroke. Sub-analyses of multivariate Cox models by AD or VD were also assessed. The cut-off values of Z score were determined using area under the curve by a receiver operating characteristic analysis based on MACE occurrences.

Results

During a mean follow-up of 1258 ± 1044 days, 62 MACE occurred. There was not significant difference of MACE between AD and VD (33%, vs. 44%, p = 0.153). By multivariable Cox model, the higher Z score of temporal-occipital-pariental lobe was associated with increased MACE compared to the lower group (HR 2.521, 95% CI 1.465–4.337, p &lt; 0.001). In a sub-analysis of patients with AD, Z score was the most significant prognostic factor for MACE (HR 3.969, 95% CI 1.374–11.468, p = 0.011). The similar trend was observed in those with VD (HR 2.247, 95% CI 1.028–4.913, p = 0.043). Conclusion: This study demonstrated that the Z score of temporal-occipital-pariental lobe by 99mTc-ECD brain perfusion SPECT could be a potential prognostic value among patients with AF and dementia, regardless of type of dementia.

Effects of astaxanthin supplementation and electrical stimulation on muscle atrophy and decreased oxidative capacity in soleus muscle during hindlimb unloading in rats

The effects of a combination of the antioxidant astaxanthin (AX) and electrical stimulation (ES) on muscle mass and mitochondrial oxidative capacity were investigated in the soleus muscle of hindlimb unloaded rats. Five groups of male Sprague-Dawley rats were used; control, 1-week hindlimb unloading (HU), HU + AX, HU + ES, and HU + AX + ES. Respective rats in the AX groups received 50-mg/kg AX twice daily during HU. Calf muscles of rats in the ES groups were electrically stimulated for 240 s/day during HU. One-week HU decreased muscle mass along with decreased FoxO3a phosphorylation and increased ubiquitinated proteins expressions, decreased oxidative enzymatic activity accompanied with decline in PGC-1α protein expression, and increased reactive oxygen species production. However, the combination treatment could synergistically attenuate/suppress all HU-related changes, suggesting protective effects on muscle atrophy and decreased muscle oxidative capacity due to chronic neuromuscular inactivity.

Effects of combined treatment with blood flow restriction and low-intensity electrical stimulation on diabetes mellitus-associated muscle atrophy in rats

BACKGROUND

Diabetes mellitus (DM) results in decreased muscle mass and harmful complications. Blood flow restriction (Bfr) and electrical stimulation (ES) increase muscle protein synthesis. We hypothesized that combined Bfr and low-intensity ES may be more effective in preventing diabetes-associated muscle atrophy by inhibiting the downregulation of protein synthesis-related pathways. In this study, the effects of combined Bfr and low-intensity ES on diabetes-associated muscle atrophy were investigated by evaluating advanced glycation end-products (AGEs) and receptor for AGEs (RAGE) in rats.

METHODS

Twenty-four Goto-Kakizaki (GK) rats were randomly divided into four treatment groups: sedentary DM, DM + Bfr (pressure cuffs placed around the thigh), DM + ES, and DM + Bfr + ES. Six Wistar rats were used as an age-matched control. Levels of AGEs and the expression of RAGE, extracellular signal-regulated kinase (ERK), and ribosomal protein S6 (rpS6) were determined in plantaris muscles.

RESULTS

Diabetes resulted in a loss of muscle mass and upregulation of AGEs and RAGE in the plantaris muscle compared with the control group. Treatment with Bfr and ES alone failed to attenuate diabetes-associated loss of muscle mass, and could not prevent the upregulation of AGEs. However, the combination of Bfr and ES prevented the diabetes-associated decrease in muscle mass and upregulation of AGEs. In addition, the combination treatment prevented diabetes-associated decreases in the expression of phosphorylated rpS6.

CONCLUSIONS

Combination treatment with Bfr and ES may prevent diabetes-associated muscle atrophy by upregulating inhibition of AGEs, which leads to the activation of protein synthesis.

A comparison of the effect of large and small metal-on-metal bearings in total hip arthroplasty on metal ion levels and the incidence of pseudotumour

Aims

The purpose of this study was to compare two different types of metal-on-metal (MoM) bearing for total hip arthroplasty (THA): one with a large femoral head (38 mm to 52 mm) and the other with a conventional femoral head (28 mm or 32 mm). We compared clinical outcome, blood metal ion levels, and the incidence of pseudotumour in the two groups.

Patients and Methods

Between December 2009 and December 2011, 62 patients underwent MoM THA with a large femoral head (Magnum group) and 57 patients an MoM THA with a conventional femoral head (conventional group). Clinical outcome was assessed using the Harris Hip score, University of California, Los Angeles (UCLA) activity score and EuroQol-5D (EQ-5D). Blood metal ion levels were measured and MRI scans were analyzed at a minimum of five years postoperatively.

Results

No acetabular component was implanted with more than 50° of inclination in either group. The Harris Hip Score, UCLA activity score, and EQ-5D improved postoperatively in both groups; no significant clinical differences were noted between the groups. The blood cobalt ion levels in the conventional group continued to rise postoperatively to five years while reaching a plateau at two years postoperatively in the Magnum group. At five years, the mean cobalt ion level of 1.16 μg/l (sd 1.32) in the Magnum group was significantly lower than the 3.77 μg/l (sd 9.80) seen in the conventional group (p = 0.0015). The incidence of moderate to severe pseudotumour was 4.7% in the Magnum group and 20.6% in the conventional group. There were no dislocations in the Magnum group and two in the conventional group. One patient in the Magnum group underwent revision for pseudotumour at 4.7 years postoperatively.

Conclusion

At five years, a well-positioned large head MoM THA has a significantly lower level of metal ion release and a lower incidence of moderate to severe pseudotumour than a MoM bearing of conventional size. Cite this article: Bone Joint J 2018;100-B:1018–24.

Shubnikov-de Haas oscillations in p and n-type topological insulator (Bi x Sb1-x )2Te3

We show Shubnikov-de Haas (SdH) oscillations in topological insulator (Bi _x Sb_1-x )₂Te₃ flakes whose carrier types are p-type (x  =  0.29, 0.34) and n-type (x  =  0.42). The physical properties such as the Berry phase, carrier mobility, and scattering time significantly changed by tuning the Fermi-level position with the concentration x. The analyses of SdH oscillations by Landau-level fan diagram, Lifshitz-Kosevich theory, and Dingle-plot in the p-type samples with x  =  0.29 and 0.34 showed the Berry phase of zero and a relatively low mobility (2000-6000 cm² V^-1 s^-1). This is due to the dominant bulk component in transport. On the other hand, the mobility in the n-type sample with x  =  0.42 reached a very large value ~17 000 cm² V^-1 s^-1 and the Berry phase of near π, whereas the SdH oscillations were neither purely two- nor three-dimensional. These suggest that the transport channel has a surface-bulk coupling state which makes the carrier scattering lesser and enhances the mobility and has a character between two- and three-dimension.

Abstract P3-08-11: The prognostic impact of retinoic acid-induced 2 (RAI2) expression in ERα-positive breast cancer patients

Background: Breast cancer cells disseminate to the bone marrow and form bone metastases in a large majority of late-stage patients. Retinoic Acid-Induced 2 (RAI2) was reported as a putative suppressor of early hematogenous dissemination of tumor cells to the bone marrow in breast cancer, particularly in estrogen receptor α (ERα)-positive breast cancer. Here, we investigated mRNA expression of RAI-2 in breast cancer patients during long-term follow-up.

Materials and methods: A total of 451 invasive breast cancer tissues was available for analysis of RAI2 mRNA using a TaqMan PCR system. We also sought correlations between clinicopathological factors and levels of RAI2 expression in these samples. The expression of markers associated with tumor-initiating capacity, such as SNAI1, SNAI2 and VIM was also analyzed. The median follow-up period was 9.0 years. Survival curves were analyzed using the Kaplan-Meier method. Cox proportional hazards regression analysis was used for univariate and multivariate analyses of prognostic values.

Results: We found positive correlations between low expression of RAI2 mRNA and shorter disease-free survival and overall survival in breast cancer patients (P=0.003, P&lt;0.0001, respectively), which was limited to ERα-positive patients (P=0.04, P=0.0009, respectively), and not seen in ERα-negative patients (P=0.52, P=0.27, respectively). Low RAI2 mRNA levels were positively correlated with high grade, ERα-negativity and PgR negativity. Multivariate analysis indicated that low level RAI2 mRNA expression was an independent factor for survival both overall in breast cancer and in ERα-positive breast cancer patients

Multivariate analysis (ERα-positive breast cancer patients)  OS  Multivariate patientsp valueHR(95%CI)Tumor size≤2cm1390.83691 (Reference) &gt;2cm207 1.08(0.54-2.28)Node statusNegative176&lt;0.00011 (Reference) Positive144 4.72(2.33-10.34)Grade11240.95921 (Reference) 2•3218 0.98(0.50-2.14)RAI2 mRNA expressionhigh140&lt;0.00011 (Reference) middle•low206 4.79(2.14-12.78)

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Conclusion:We show that low expression of RAI2 is an independent factor predictive of a poor prognosis in ERα-positive breast cancer patients. RAI2 could be a promising candidate biomarker and therapeutic target in ERα-positive breast cancer to prevent dissemination to the bone marrow.

Citation Format: Nishikawa S, Kondo N, Endo Y, Hato Y, Hisada T, Nishimoto M, Dong Y, Okuda K, Kato H, Takahashi S, Nakanishi R, Toyama T. The prognostic impact of retinoic acid-induced 2 (RAI2) expression in ERα-positive breast cancer patients [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-08-11.

Elucidation of Spatial Distribution of Hydrophobic Aromatic Compounds Encapsulated in Polymer Micelles by Anomalous Small-Angle X-ray Scattering

Spatial distribution of bromobenzene (BrBz) and 4-bromophenol (BrPh) as hydrophobic aromatic compounds incorporated in polymer micelles with vesicular structure consisting of poly(ethylene glycol)-b-poly(tert-butyl methacrylate) (PEG-b-PtBMA) in aqueous solution is investigated by anomalous small-angle X-ray scattering (ASAXS) analyses near Br K edge. Small-angle X-ray scattering (SAXS) intensities from PEG-b-PtBMA micelles containing BrBz and BrPh were decreased as the energy of incident X-ray approached to Br K edge corresponding to the energy dependence of anomalous scattering factor of Br. The analysis for the energy dependence of SAXS profiles from the PEG-b-PtBMA micelles containing BrBz revealed that BrBz molecules were located in hydrophobic layer of PEG-b-PtBMA micelles. On the contrary, it was found by ASAXS that BrPh existed not only in the hydrophobic layer but also in the shell layer. Since ASAXS analysis successfully accomplished to visualize the spatial distribution of hydrophobic molecules in polymer micelles, it should be expected to be a powerful tool for characterization of drug delivery vehicles.