An artificial impact on the asteroid (162173) Ryugu formed a crater in the gravity-dominated regime

The Hayabusa2 spacecraft investigated the small asteroid Ryugu, which has a rubble-pile structure. We describe an impact experiment on Ryugu using Hayabusa2's Small Carry-on Impactor. The impact produced an artificial crater with a diameter >10 meters, which has a semicircular shape, an elevated rim, and a central pit. Images of the impact and resulting ejecta were recorded by the Deployable CAMera 3 for >8 minutes, showing the growth of an ejecta curtain (the outer edge of the ejecta) and deposition of ejecta onto the surface. The ejecta curtain was asymmetric and heterogeneous and it never fully detached from the surface. The crater formed in the gravity-dominated regime; in other words, crater growth was limited by gravity not surface strength. We discuss implications for Ryugu's surface age.

Incidence rate and risk factors for radiographic hip osteoarthritis in Japanese men and women: a 10-year follow-up of the ROAD study

OBJECTIVE

To investigate the incidence and progression rate of radiographic hip osteoarthritis (OA) and its risk factors in Japanese men and women using a large-scale population of a nationwide cohort study, Research on Osteoarthritis/osteoporosis Against Disability (ROAD).

METHODS

From the baseline survey of the ROAD study, 2,975 participants (1,043 men and 1,932 women) aged 23-94 years (mean, 70.2 years) living in urban, mountainous, and coastal communities were followed up with hip radiography at 3, 7, and 10 years (mean follow-up, 7.1 years). Radiographs were scored using the Kellgren/Lawrence (K/L) grading system, and radiographic hip OA was defined as K/L ≥ 2. The incidence and progression rate of hip OA were examined. Acetabular dysplasia was defined as a central-edge angle <20°. Cox's proportional hazard model was used to assess risk factors for incident and progressive radiographic hip OA.

RESULTS

The incidence rate of radiographic hip OA was 5.6/1,000 person-years and 8.4/1,000 person-years in men and women, respectively. The progression rate of hip OA was 2.2/1,000 person-years and 6.0/1,000 person-years in men and women, respectively. The significant risk factors for incident hip OA were age, obesity, and acetabular dysplasia at baseline (hazard risk [HR] 1.05, 95% confidence interval [CI] 1.03-1.08; 1.78, 1.10-2.75; 2.06, 1.30-3.17, respectively). The significant risk factors for progressive hip OA were baseline hip pain and acetabular dysplasia (HR 5.68, 95%CI 1.07-22.61; 14.78, 3.66-56.06, respectively).

CONCLUSION

Continued longitudinal surveys of the ROAD study will contribute to knowledge about and potential prevention of incident and progressive hip OA.

The first case of chronic pulmonary Mycobacterium shigaense infection in an immunocompetent patient

Mycobacterium shigaense has recently been recognized as an emerging human pathogen, and is well known as a skin pathogen in immunocompromised individuals. In this report we describe the first case of chronic pulmonary infectious disease caused by M. shigaense in an immunocompetent individual.

Classification of osteonecrosis of the femoral head: Who should have surgery?

Objectives

Using a simple classification method, we aimed to estimate the collapse rate due to osteonecrosis of the femoral head (ONFH) in order to develop treatment guidelines for joint-preserving surgeries.

Methods

We retrospectively analyzed 505 hips from 310 patients (141 men, 169 women; mean age 45.5 years (sd 14.9; 15 to 86)) diagnosed with ONFH and classified them using the Japanese Investigation Committee (JIC) classification. The JIC system includes four visualized types based on the location and size of osteonecrotic lesions on weightbearing surfaces (types A, B, C1, and C2) and the stage of ONFH. The collapse rate due to ONFH was calculated using Kaplan–Meier survival analysis, with radiological collapse/arthroplasty as endpoints.

Results

Bilateral cases accounted for 390 hips, while unilateral cases accounted for 115. According to the JIC types, 21 hips were type A, 34 were type B, 173 were type C1, and 277 were type C2. At initial diagnosis, 238/505 hips (47.0%) had already collapsed. Further, the cumulative survival rate was analyzed in 212 precollapsed hips, and the two-year and five-year collapse rates were found to be 0% and 0%, 7.9% and 7.9%, 23.2% and 36.6%, and 57.8% and 84.8% for types A, B, C1, and C2, respectively.

Conclusion

Type A ONFH needs no further treatment, but precollapse type C2 ONFH warrants immediate treatment with joint-preserving surgery. Considering the high collapse rate, our study results justify the importance of early diagnosis and intervention in asymptomatic patients with type C2 ONFH.

Cite this article: Y. Kuroda, T. Tanaka, T. Miyagawa, T. Kawai, K. Goto, S. Tanaka, S. Matsuda, H. Akiyama. Classification of osteonecrosis of the femoral head: Who should have surgery?. Bone Joint Res 2019;8:451–458. DOI: 10.1302/2046-3758.810.BJR-2019-0022.R1.

Challenges in a population-based registry of cardiovascular disease in Shiga, Japan

Background

Stroke and cardiovascular disease are one of the leading causes of death and disability in Japan. In order to investigate current burden, we conduct a population-based registry of cardiovascular disease in Shiga Prefecture, Japan since 2012. We will demonstrate challenges in conduct of the registry study.

Methods

In 2012, we established the Shiga Stroke Registry (SSR), a multicenter population-based registry study designed to build a complete information system for the management of stroke in Shiga Prefecture, Japan. The registry uses local monitoring, combined with remote data collection and quality control systems, to create an integrated surveillance system among a network of all acute care hospitals with neurology/neurosurgery facilities and smaller hospitals with rehabilitation facilities in the region. In 2019, study name has changed to Shiga Stroke and Heart Attack Registry (SSHR) and additional registration of coronary heart disease and aortic disease have started. Each case is reviewed and adjudicated by 2 or more specialists.

Results

In the financial year of 2018 (from April to March), a total of 4809 stroke cases were identified. From December 2018 to April 2019, a total of 515 coronary heart and aortic diseases were identified. A total 10 nurses work full-time for the registry and it takes average of 1 hour to collect information for each patient. Challenges in conduct of the cardiovascular registry involve regulatory and ethical approval, funding, associations with local hospitals, non-standardized hospital diagnosis, staff training for comprehensive data collection including pathophysiology, examination and treatment, and quality control of data collection.

Conclusions

SSHR is a population-based registry of wide range of stroke and cardiovascular disease in Shiga Prefecture, Japan. In order to keep quality of the data, we put a lot of efforts on staff training and quality control.

Key messages

Population-based registry of wide range of stroke and cardiovascular disease in Shiga, Japan. In order to keep quality of the data, we put a lot of efforts on staff training and quality control.

A population-based study identifies an association of THBS2 with intervertebral disc degeneration

OBJECTIVE

To clarify the genetic mechanisms underlying intervertebral disc degeneration (IDD), we examined the associations between single-nucleotide polymorphisms (SNPs) and indicated as coefficient of interaction term (IDD) in a general population in Japan.

METHODS

This was a cross-sectional study. In 1,605 participants, C2-3 to L5/S1 in the total spine magnetic resonance imaging (MRI) were evaluated using the Pfirrmann's scoring system. Disc scores of 4 and 5 were defined as IDD. Eight SNPs in eight genes associated with IDD were examined at each disc level, considering the non-genetic risk factors of age, sex, and body mass index (BMI).

RESULTS

The highest odds ratio was found for rs9406328 in the THBS2 gene at disc level T12-L1 (OR 1.27, 95%CI 1.05 to 1.53), and this association was strengthened after adjustment for age using logistic regression (OR 1.37, 95%CI 1.12 to 1.67). Among participants aged <50 years and 50-59, the average IDD score in those with 2 risk alleles of rs9406328 was markedly higher than in those with 0 or 1 risk allele, and the difference is much wider than the elderly participants. It indicates the genetic effect of rs9406328 is stronger in the younger age groups. Finally, multiple linear regression analyses of the association between rs9406328 and IDD, adjusted for age, sex, and BMI at each disc level, showed a statistical interaction between age and the number of risk alleles at C7-T1, T3-4 and T4-T5 as well as T12-L1.

CONCLUSION

CONCLUSION: The association between rs9406328 in THBS2 and IDD was replicated. The contributions of genetic and environmental factors to IDD differed by disc level.

P6234The relationship of alcohol consumption with risk factors of coronary heart disease and the intake of macro- and micro-nutrients in Japanese: the INTERLIPID study

Background

Many studies have reported the J-shaped relationship between alcohol consumption and coronary heart disease (CHD) risk; therefore, light-drinkers is generally recognized to be associated with the lower risk of CHD. However, the mechanisms of lower risk for CHD in light-drinkers are still unclear. Alcohol drinking status is likely to be associated with not only CHD risk factors but also dietary intake. Nevertheless, few studies report these relationships in detail.

Purpose

The purpose of this study is to evaluate the relationships of alcohol drinking status with CHD classical risk factors and the intake of macro- and micro- nutrients in Japanese.

Methods

Study participants were 1,090 Japanese men and women aged 40–59 years from The INTERLIPID study excepted for 55 individuals who had missing data (n=26) and were past-drinkers (n=29). Alcohol consumption was assessed with two 7-day alcohol records, and average ethanol intake (per week) was calculated. Participants were classified into following 4 groups: non-drinkers (0g/week), light-drinkers (<100 g/week), moderate-drinkers (100–299 g/week), and heavy-drinkers (≥300 g/week). Serum LDL and HDL cholesterol, blood pressure (BP), the prevalence of hypertension and dyslipidemia, and smoking status were assessed as CHD risk factors. The intake of energy and macro- and micro-nutrients were evaluated from the four-timed in-depth 24-hr dietary recalls. Nutrient intake densities were calculated per total energy intake without alcohol. The analysis of variance and chi-squared test were used to evaluate the relations of alcohol status with CHD risk factors and nutrient intake.

Results

Serum HDL cholesterol levels increased and LDL cholesterol levels decreased with increasing alcohol consumption. Systolic and diastolic BP increased with increasing alcohol consumption. J-shaped relationships with alcohol consumption were observed for the proportion of current smoker, number of cigarettes, and the prevalence of hypertension; that is, light-drinkers was lowest among all groups. The prevalence of dyslipidemia was the highest in non-drinkers, and decreased with increasing alcohol consumption. In heavy-drinkers, total energy (kcal/day) was the highest, but energy intake without alcohol (kcal/day) was the lowest. For macronutrients, the intake of carbohydrate (%kcal) decreased, and the intakes of total and animal protein (%kcal) increased with increasing alcohol consumption. The intakes of total cholesterol (mg/1000kcal) and sodium (mg/1000kcal) increased, and total fiber (g/1000kcal) decreased with increasing alcohol consumption. These associations were similar in men and women.

Conclusions

Alcohol consumption was related with not only CHD classical risk factors but also the intake of macro- and micro-nutrients. Non-drinkers had a higher proportion of some CHD risk factors than light-drinkers. These results might influence on J-shaped relationship between alcohol consumption and CHD risk.

Acknowledgement/Funding

1: Ministry of Education, Science, Sports, and Culture of Japan, 2: National Institutes of Health, Bethesda, MD, USA

Mechanical regulation of bone homeostasis through p130Cas-mediated alleviation of NF-κB activity

Mechanical loading plays an important role in bone homeostasis. However, molecular mechanisms behind the mechanical regulation of bone homeostasis are poorly understood. We previously reported p130Cas (Cas) as a key molecule in cellular mechanosensing at focal adhesions. Here, we demonstrate that Cas is distributed in the nucleus and supports mechanical loading-mediated bone homeostasis by alleviating NF-κB activity, which would otherwise prompt inflammatory processes. Mechanical unloading modulates Cas distribution and NF-κB activity in osteocytes, the mechanosensory cells in bones. Cas deficiency in osteocytes increases osteoclastic bone resorption associated with NF-κB-mediated RANKL expression, leading to osteopenia. Upon shear stress application on cultured osteocytes, Cas translocates into the nucleus and down-regulates NF-κB activity. Collectively, fluid shear stress-dependent Cas-mediated alleviation of NF-κB activity supports bone homeostasis. Given the ubiquitous expression of Cas and NF-κB together with systemic distribution of interstitial fluid, the Cas-NF-κB interplay may also underpin regulatory mechanisms in other tissues and organs.

Bovine Endocarditis Associated with Mycoplasma bovis

Mycoplasma bovis is a microorganism associated with pneumonia, mastitis, arthritis and otitis media of cattle; however, there are no reports of this organism causing bovine endocarditis. Five adult cattle with endocarditis characterized by caseated lesions (diameter 5-12 cm) of the endocardial surface of the left atrium, but without lesions in heart valves or affecting the right side of the heart, were identified in slaughterhouses in Japan. M. bovis was successfully isolated from the lesions and M. bovis antigen was detected immunohistochemically within the lesions. The results suggest that the lesions may have been associated with M. bovis alone. To our knowledge, this is the first demonstration of bovine endocarditis associated with M. bovis.

Hayabusa2 arrives at the carbonaceous asteroid 162173 Ryugu-A spinning top-shaped rubble pile

The Hayabusa2 spacecraft arrived at the near-Earth carbonaceous asteroid 162173 Ryugu in 2018. We present Hayabusa2 observations of Ryugu's shape, mass, and geomorphology. Ryugu has an oblate "spinning top" shape, with a prominent circular equatorial ridge. Its bulk density, 1.19 ± 0.02 grams per cubic centimeter, indicates a high-porosity (>50%) interior. Large surface boulders suggest a rubble-pile structure. Surface slope analysis shows Ryugu's shape may have been produced from having once spun at twice the current rate. Coupled with the observed global material homogeneity, this suggests that Ryugu was reshaped by centrifugally induced deformation during a period of rapid rotation. From these remote-sensing investigations, we identified a suitable sample collection site on the equatorial ridge.