Dynamic ultrasound reveals the specific behavior of the medial meniscus extrusion in patients with knee osteoarthritis

BACKGROUND

In the dynamic condition, knee osteoarthritis (OA) usually presents with pain. In the weight-bearing condition, a medial meniscus extrusion (MME) may cause severe symptoms and pathological progression. However, the correlation between a dynamic MME and pain has not been elucidated. Now, an MME can be evaluated under dynamic conditions and reflect the characteristics of symptomatic knee OA. This study investigated MMEs during walking and their correlation with knee pain.

METHODS

Thirty-two symptomatic patients with knee OA (mean age, 60.5 ± 9.9 years) were enrolled in this study. The medial meniscus was evaluated using ultrasonograms during walking, and in the static supine and unipedal standing positions, as dynamic and static conditions, respectively. The ΔMME (the difference between the maximum and minimum MMEs) was obtained in each condition. The intensity of the knee pain during walking was measured by the visual analog scale (VAS).

RESULTS

The ΔMME in the dynamic condition was significantly higher than that in the static condition (P < 0.01). There was a significant correlation between VAS and ΔMME only in the dynamic condition.

CONCLUSIONS

The dynamic evaluation is a valid tool for understanding the mechanisms of knee pain and the behavior of the medial meniscus in symptomatic knee OA.

The effect of gait modification on the response of medial meniscus extrusion during gait in patients with knee osteoarthritis

BACKGROUND

An increase in medial meniscus extrusion during weight-bearing conditions is associated with the progression of medial knee osteoarthritis (OA). Toe-out gait modification has been known to reduce the knee adduction moment (KAM); however, its effect on reducing the increase in medial meniscus extrusion in patients with knee OA remains unclear.

RESEARCH QUESTION

To (1) evaluate the effect of toe-out gait on the increase in medial meniscus extrusion and the KAM in patients with medial knee OA and (2) investigate the synergetic effect of lateral wedge insoles in combination with toe-out gait in determining the most effective intervention for reducing medial meniscus extrusion during gait.

METHODS

Twenty-five patients with medial knee OA were enrolled in this study. Participants walked under four conditions: normal gait, toe-out gait, normal gait with lateral wedge insoles, and toe-out gait with lateral wedge insoles. Medial meniscus extrusion and KAM peaks during gait were measured using ultrasound and a three-dimensional motion analysis system in each condition. These parameters were compared among the four conditions using repeated measures analysis of variance.

RESULTS

The increase in medial meniscus extrusion and the second KAM peak were significantly lower in all interventions compared with those observed during normal gait. However, there was no significant difference among the interventions.

SIGNIFICANCE

This study suggested that toe-out gait reduces the increase in medial meniscus extrusion and is associated with the reduction of the second KAM peak. However, no synergistic effect of lateral wedge insoles and toe-out gait was observed.

Human Trials on the Prevention of Tunnel Widening by the Emdogain in Anterior Cruciate Ligament Reconstruction

Background Although anterior cruciate ligament reconstruction (ACLR) is an established procedure, some problems remain, such as bone tunnel widening after ACLR. In animal studies, Emdogain (EMD) prevented tunnel widening by promoting tendon-bone healing. This study aimed to evaluate the effects of EMD on the prevention of tunnel widening after anterior cruciate ligament (ACL) injury in humans. Methods Nineteen patients who underwent ACLR were included. Seven patients in the EMD group were administered EMDs into the femoral tunnel during ACLR, while 12 patients in the control group were not administered EMDs. After surgery, at two and four weeks and three, six, and 12 months, femoral and tibial tunnel widening were evaluated on computed tomography images. Anteroposterior laxity and clinical scores such as the Lysholm score, the International Knee Documentation Committee (IKDC) subjective form, and the Knee Injury and Osteoarthritis Outcome Score (KOOS) were assessed before surgery and 12 months postoperatively. Results Tunnel widening on the femoral side was significantly smaller in the EMD group than in the control group at two weeks. However, there was no significant difference between the two groups at 12 months. There were no significant differences in anteroposterior laxity and clinical scores between the groups before and 12 months after surgery. Conclusion EMD administration into the bone tunnel did not prevent tunnel widening at 12 months after ACLR, although tunnel widening of the femoral tunnel was reduced by EMD administration in the early phase.

Single-cell RNA-seq analysis identifies distinct myeloid cells in a case with encephalitis temporally associated with COVID-19 vaccination

Recently accumulating evidence has highlighted the rare occurrence of COVID-19 vaccination-induced inflammation in the central nervous system. However, the precise information on immune dysregulation related to the COVID-19 vaccination-associated autoimmunity remains elusive. Here we report a case of encephalitis temporally associated with COVID-19 vaccination, where single-cell RNA sequencing (scRNA-seq) analysis was applied to elucidate the distinct immune signature in the peripheral immune system. Peripheral blood mononuclear cells (PBMCs) were analyzed using scRNA-seq to clarify the cellular components of the patients in the acute and remission phases of the disease. The data obtained were compared to those acquired from a healthy cohort. The scRNA-seq analysis identified a distinct myeloid cell population in PBMCs during the acute phase of encephalitis. This specific myeloid population was detected neither in the remission phase of the disease nor in the healthy cohort. Our findings illustrate induction of a unique myeloid subset in encephalitis temporally associated with COVID-19 vaccination. Further research into the dysregulated immune signature of COVID-19 vaccination-associated autoimmunity including the cerebrospinal fluid (CSF) cells of central nervous system (CNS) is warranted to clarify the pathogenic role of the myeloid subset observed in our study.

Cumulative knee adduction moment during jogging causes temporary medial meniscus extrusion in healthy volunteers

PURPOSE

The cumulative knee adduction moment (KAM) is a key parameter evaluated for the prevention of overload knee injuries on the medial compartment. Medial meniscus extrusion (MME), typical in hoop dysfunctions, is a measure for the cumulative mechanical stress in individual knees; however, its correlation with cumulative KAM is unknown. The aim of this study was to investigate the effect of temporary overload stress on MME and its correlation with cumulative KAM.

METHODS

Thirteen healthy asymptomatic volunteers (13 knees) were recruited for a cohort study (mean age, 23.1 ± 3.3 years; males: n = 8). The cumulative KAM was calculated using a three-dimensional motion analysis system, in addition to the number of steps taken while jogging uphill or downhill. MME was evaluated using ultrasound performed in the standing position. The evaluations were performed four times: at baseline (T0), before and after (T1 and T2, respectively) jogging uphill or downhill, and 1 day after (T3) jogging. Additionally, the Δ-value was calculated using the change of meniscus after efforts as the difference in MME between T1 and T2.

RESULTS

The MME in T2 was significantly greater than those in T0 and T1. Conversely, the MME in T3 was significantly lesser than that in T2. No significant difference was found between those in T0 and T1, and T3. ΔMME exhibited a significant positive correlation with the cumulative KAM (r = 0.68, p = 0.01), but not for peak KAM.

CONCLUSION

The temporary reaction of MME observed in ultrasound correlates with the cumulative stress of KAM.

miR-23a/b clusters are not essential for the pathogenesis of osteoarthritis in mouse aging and post-traumatic models

Osteoarthritis (OA), the most prevalent aging-related joint disease, is characterized by insufficient extracellular matrix synthesis and articular cartilage degradation and is caused by various risk factors including aging and traumatic injury. Most microRNAs (miRNAs) have been associated with pathogenesis of osteoarthritis (OA) using in vitro models. However, the role of many miRNAs in skeletal development and OA pathogenesis is uncharacterized in vivo using genetically modified mice. Here, we focused on miR-23-27-24 clusters. There are two paralogous miR-23-27-24 clusters: miR-23a-27a-24-2 (miR-23a cluster) and miR-23b-27b-24-1 (miR-23b cluster). Each miR-23a/b, miR-24, and miR-27a/b is thought to function coordinately and complementary to each other, and the role of each miR-23a/b, miR-24, and miR-27a/b in OA pathogenesis is still controversial. MiR-23a/b clusters are highly expressed in chondrocytes and the present study examined their role in OA. We analyzed miRNA expression in chondrocytes and investigated cartilage-specific miR-23a/b clusters knockout (Col2a1-Cre; miR-23a/bflox/flox: Cart-miR-23clus KO) mice and global miR-23a/b clusters knockout (CAG-Cre; miR-23a/bflox/flox: Glob-miR-23clus KO) mice. Knees of Cart- and Glob-miR-23a/b clusters KO mice were evaluated by histological grading systems for knee joint tissues using aging model (12 and/or 18 month-old) and surgically-induced OA model. miR-23a/b clusters were among the most highly expressed miRNAs in chondrocytes. Skeletal development of Cart- and Glob-miR-23clus KO mice was grossly normal although Glob-miR-23clus KO had reduced body weight, adipose tissue and bone density. In the aging model and surgically-induced OA model, Cart- and Glob-miR-23clus KO mice exhibited mild OA-like changes such as proteoglycan loss and cartilage fibrillation. However, the histological scores were not significantly different in terms of the severity of OA in Cart- and Glob-miR-23clus KO mice compared with control mice. Together, miR-23a/b clusters, composed of miR-23a/b, miR-24, miR-27a/b do not significantly contribute to OA pathogenesis.

The role of substance P on maintaining ligament homeostasis by inhibiting endochondral ossification during osteoarthritis progression

PURPOSE

Osteoarthritis (OA) is characterized by the degeneration of various tissues, including ligaments. However, pathological changes such as chondrogenesis and ossification in ligaments during OA are still unclear. Substance P (SP), a neuropeptide, has various functions including bone metabolism. This study aimed to analyze the expression and function of SP in OA ligaments, and the therapeutic potential of SP agonists in OA mice.

MATERIALS AND METHODS

Expressions of SP, SOX9, and MMP13 were histologically analyzed in the posterior cruciate ligament (PCL) in humans with OA and Senescence-accelerated mouse-prone 8 (SAMP8) mice as a spontaneous OA model. The effect of SP agonists on chondrogenesis was evaluated using human ligament cells. Finally, SP agonists were administered intraperitoneally to destabilized medial meniscus (DMM) mice, and the PCL was histologically evaluated.

RESULTS

In PCL of humans and mice, the expression of SP, SOX9, and MMP13 was upregulated as OA progressed, but their expression was downregulated in severe degeneration. SP and SOX9 were co-expressed in chondrocyte-like cells. In ligament cells, SP agonists downregulated SOX9, RUNX2, and COL10A1. On evaluating chondrogenesis in ligament cells, pellet diameter was reduced in those treated with the SP agonists compared to those untreated. Administration of SP agonists ameliorated PCL degeneration in DMM mice. The Osteoarthritis Research Society and ligament scores in mice with SP agonists were significantly lower than those without SP agonists.

CONCLUSIONS

SP plays an important role in maintaining ligament homeostasis by inhibiting endochondral ossification during OA progression. Targeting SP has therapeutic potential for preventing ligament degeneration.

Single-cell transcriptomics of the goldfish retina reveals genetic divergence in the asymmetrically evolved subgenomes after allotetraploidization

The recent whole-genome duplication (WGD) in goldfish (Carassius auratus) approximately 14 million years ago makes it a valuable model for studying gene evolution during the early stages after WGD. We analyzed the transcriptome of the goldfish retina at the level of single-cell (scRNA-seq) and open chromatin regions (scATAC-seq). We identified a group of genes that have undergone dosage selection, accounting for 5% of the total 11,444 ohnolog pairs. We also identified 306 putative sub/neo-functionalized ohnolog pairs that are likely to be under cell-type-specific genetic variation at single-cell resolution. Diversification in the expression patterns of several ohnolog pairs was observed in the retinal cell subpopulations. The single-cell level transcriptome analysis in this study uncovered the early stages of evolution in retinal cell of goldfish after WGD. Our results provide clues for understanding the relationship between the early stages of gene evolution after WGD and the evolution of diverse vertebrate retinal functions.

Evaluation of the flexion gap with a distal femoral trial component in posterior-stabilized total knee arthroplasty

Purpose

A distal femoral trial component was manufactured, and flexion gap size and inclination were evaluated with or without the distal femoral trial component in total knee arthroplasty (TKA). This study aimed to evaluate the effect of the distal femoral trial component on flexion gap size and joint inclination in posterior-stabilized (PS)-TKA.

Materials and methods

A total of 84 patients with medial osteoarthritis who underwent mobile-bearing PS-TKA using modified gap techniques were included in this retrospective study. The flexion gap size and inclination before and after setting the distal femoral trial component were evaluated and compared with the final gap size and inclination.

Results

The joint gap size and inclination were significantly lower in those with than in those without the distal femoral trial component (P = 0.005, P < 0.001). The final gap size and inclination were similar to the gap size and inclination with the distal trial component (P = 0.468, P = 0.158).

Conclusions

The joint gap size and medial tension in PS-TKA were significantly reduced after setting the distal femoral trial component. The flexion gap measured using the distal femoral trial component was similar to that when the final trial component was set. To more accurately perform the gap technique TKA, the flexion gap should be measured using the distal femoral trial component.

Transcriptional differences between coronavirus disease 2019 and bacterial sepsis

BACKGROUND

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2, has led to major public health crises worldwide. Several studies have reported the comprehensive mRNA expression analysis of immune-related genes in patients with COVID-19, using blood samples, to understand its pathogenesis; however, the characteristics of RNA expression in COVID-19 and bacterial sepsis have not been compared. The current study aimed to address this gap.

METHODS

RNA-sequencing and bioinformatics analyses were used to compare the transcriptome expression of whole blood samples from patients with COVID-19 and patients with sepsis who were admitted to the intensive care unit of Osaka University Graduate School of Medicine.

RESULTS

The COVID-19 and sepsis cohorts showed upregulation of mitochondrial- and neutrophil-related transcripts, respectively. Compared with that in the control cohort, neutrophil-related transcripts were upregulated in both the COVID-19 and sepsis cohorts. In contrast, mitochondrial-related transcripts were upregulated in the COVID-19 cohort and downregulated in the sepsis cohort, compared to those in the control cohort. Moreover, transcript levels of the pro-apoptotic genes BAK1, CYCS, BBC3, CASP7, and CASP8 were upregulated in the COVID-19 cohort, whereas those of anti-apoptotic genes, such as BCL2L11 and BCL2L1, were upregulated in the sepsis cohort.

CONCLUSIONS

This study clarified the differential expression of transcripts related to neutrophils and mitochondria in sepsis and COVID-19 conditions. Mitochondrial-related transcripts were downregulated in sepsis than in COVID-19 conditions, and our results indicated suboptimal intrinsic apoptotic features in sepsis samples compared with that in COVID-19 samples. This study is expected to contribute to the development of specific treatments for COVID-19.

Infants’ Prediction of Humanoid Robot’s Goal-Directed Action

Several studies have shown that infants anticipate human goal-directed actions, but not robot’s ones. However, the studies focusing on the robot goal-directed actions have mainly analyzed the effect of mechanical arms on infant’s attention. To date, the prediction of goal-directed actions in infants has not yet been studied when the agent is a humanoid robot. Given this lack of evidence in infancy research, the present study aims at analyzing infants’ action anticipation of both a human’s and a humanoid robot’s goal-directed action. Data were acquired on thirty 17-month-old infants, watching four video clips, where either a human or a humanoid robot performed a goal-directed action, i.e. reaching a target. Infants looking behavior was measured through the eye-tracking technique. The results showed that infants anticipated the goal-directed action of both the human and the robot and there were no differences in the anticipatory gaze behavior between the two agents. Furthermore, the findings indicated different attentional patterns for the human and the robot, showing a greater attention paid to the robot's face than the human’s face. Overall, the results suggest that 17-month-old infants may infer also humanoid robot’ underlying action goals.

Senescence-accelerated mice prone 8 (SAMP8) in male as a spontaneous osteoarthritis model

BACKGROUND

Animal models of spontaneous osteoarthritis (OA) are sparse and not well characterized. The purpose of the present study is to examine OA-related changes and mechanisms in senescence-accelerated mouse prone 8 (SAMP8) that displays a phenotype of accelerated aging.  METHODS: Knees of male SAMP8 and SAM-resistant 1 (SAMR1) mice as control from 6 to 33 weeks of age were evaluated by histological grading systems for joint tissues (cartilage, meniscus, synovium, and subchondral bone), and µCT analysis. Gene expression patterns in articular cartilage were analyzed by real-time PCR. Immunohistochemistry was performed for OA-related factors, senescence markers, and apoptosis.

RESULTS

Starting at 14 weeks of age, SAMP8 exhibited mild OA-like changes such as proteoglycan loss and cartilage fibrillation. From 18 to 33 weeks of age, SAMP8 progressed to partial or full-thickness defects with exposure of subchondral bone on the medial tibia and exhibited synovitis. Histological scoring indicated significantly more severe OA in SAMP8 compared with SAMR1 from 14 weeks [median (interquartile range): SAMR1: 0.89 (0.56-1.81) vs SAMP8: 1.78 (1.35-4.62)] to 33 weeks of age [SAMR1: 1.67 (1.61-1.04) vs SAMP8: 13.03 (12.26-13.57)]. Subchondral bone sclerosis in the medial tibia, bone mineral density (BMD) loss of femoral metaphysis, and meniscus degeneration occurred much earlier than the onset of cartilage degeneration in SAMP8 at 14 weeks of age.

CONCLUSIONS

SAMP8 are a spontaneous OA model that is useful for investigating the pathogenesis of primary OA and evaluating therapeutic interventions.

Posterior wall blowout on computed tomography after anterior cruciate ligament reconstruction

BACKGROUND

During anterior cruciate ligament (ACL) reconstruction, even when a posterior wall of the femoral bone tunnel is identified, computed tomography (CT) occasionally demonstrates a breach of the posterior femoral cortex of the femoral bone tunnel, i.e., posterior wall blowout, after ACL reconstruction (posterior wall blowout-like phenomenon). This study aimed to investigate the influence of the posterior wall blowout-like phenomenon on clinical outcomes after ACL reconstruction using hamstring tendon.

METHODS

A total of 105 patients who underwent CT examination two weeks after ACL reconstruction were enrolled. A cortical suspension device was used for femoral side fixation in all cases. Posterior wall was identified in all cases during the surgery. The side-to-side difference in anterior knee laxity, pivot shift test, Lysholm knee score, the International Knee Documentation Committee (IKDC) subjective form, and the Knee Injury and Osteoarthritis Outcome Score (KOOS) were evaluated one year after the surgery. A second CT examination was performed 6-12 months after the surgery, if a posterior wall blowout-like phenomenon was identified in the first CT examination.

RESULTS

Two weeks after the surgery, 16 of the 105 patients showed a posterior wall blowout-like phenomenon. Twelve of the 16 cases demonstrated a regenerated posterior femoral cortex of the femoral bone tunnel on their second CT images. There were no significant differences between the posterior wall blowout-like phenomenon group and the normal posterior wall group in terms of a side-to-side difference in anterior knee laxity (0.4 ± 1.5 mm and 0.1 ± 1.6 mm, respectively), pivot shift test, Lysholm knee score, IKDC score, and KOOS at one year after surgery. The length and diameter of the femoral bone tunnel were not significantly different between the two groups.

CONCLUSIONS

Posterior wall blowout-like phenomenon after ACL reconstruction using a cortical suspension device did not negatively influence clinical outcomes.

LEVEL OF EVIDENCE

III - retrospective comparative clinical study.

Tendon-Specific Dicer Deficient Mice Exhibit Hypoplastic Tendon Through the Downregulation of Tendon-Related Genes and MicroRNAs

Tendon is a fibrous connective tissue, that is, transmitting the forces that permit body movement. However, tendon/ligament biology is still not fully understood and especially, the role of miRNAs in tendon/ligament is sparse and uncharacterized in in vivo models. The objectives of this study were to address the function of DICER using mice with tendon/ligament-specific deletion of Dicer (Dicer conditional knockout; cKO), and to identify key miRNAs in tendon/ligament. Dicer cKO mice exhibited hypoplastic tendons through structurally abnormal collagen fibrils with downregulation of tendon-related genes. The fragility of tendon did not significantly affect the tensile strength of tendon in Dicer cKO mice, but they showed larger dorsiflexion angle in gait compared with Control mice. We identified two miRNAs, miR-135a and miR-1247, which were highly expressed in the Achilles tendon of Control mice and were downregulated in the Achilles tendon of Dicer cKO mice compared with Control mice. miR-135a mimic increased the expression of tendon-related genes in injured Achilles tendon-derived fibroblasts. In this study, Dicer cKO mice exhibited immature tendons in which collagen fibrils have small diameter with the downregulation of tendon-related genes such as transcriptional factor, extracellular matrix, and miRNAs. Thus, DICER plays an important role in tendon maturation, and miR-135a may have the potential to become key miRNA for tendon maturation and healing.

A larger side-to-side difference in anterior knee laxity increases the prevalence of medial and lateral meniscal injuries in patients with ACL injuries

PURPOSE

The objective of this study was to investigate factors that influence the prevalence of medial and lateral meniscal injuries at the time of anterior cruciate ligament (ACL) reconstruction in patients with ACL injuries.

METHODS

Patients with ACL injuries at 9 institutions were enrolled in this multicentre study. Age, sex, duration between injury and surgery, pivot shift test grade, anterior knee laxity determined using the Kneelax 3 arthrometer, and other variables were assessed by logistic regression analysis. Meniscal conditions were evaluated via arthroscopy.

RESULTS

In all, 830 patients were enrolled. The prevalence of medial and lateral meniscal tears was 32.0% (266 knees) and 26.5% (220 knees), respectively. Significant factors that influenced the prevalence of medial meniscal injuries were age [odds ratio (OR) 1.03; P = 0.000], side-to-side differences in instrumented anterior knee laxity before surgery (OR 1.12; P = 0.002), duration between injury and surgery (≥ 12 months) (OR 1.86; P = 0.023), and pivot shift test grade (OR 1.36; P = 0.014). Significant factors of lateral meniscal injury were side-to-side differences in anterior knee laxity before surgery (OR 1.12; P = 0.003) and the male sex (OR 1.50; P = 0.027).

CONCLUSION

Greater anterior knee laxity, age, a longer duration between injury and surgery, and a higher pivot shift test grade predicted medial meniscal injury. Greater anterior knee laxity and the male sex predicted lateral meniscal injury. In patients with ACL injuries, the importance of side-to-side differences in anterior knee laxity should be rediscovered from the viewpoint of meniscal conditions.

LEVEL OF EVIDENCE

Level III.

Equivalent outcomes of ACL revision with over-the-top single and double-bundle reconstruction using hamstring tendon compared to anatomical single and double-bundle reconstruction

Purpose

In revision anterior cruciate ligament reconstruction (ACLR), our procedure of choice is the over-the-top route (OTTR) for cases where it is difficult to use a primary bone tunnel or to create a new bone tunnel due to the enlargement or malposition of the bone tunnel. Depending on the condition of the primary bone tunnel, we choose single (bone tunnel or OTTR) or double (bone tunnel or anteromedial (AM) bundle: OTTR /posterolateral (PL) bundle: bone tunnel) for femoral fixation. This study showed the results of single and double OTTR revision ACLR using the hamstring tendon.

Methods

Seventy-eight patients, who underwent revision ACLR using the hamstring tendon and who could be followed up for more than 2 year, were included in this study. The methods of revision ACLR were single in 54 cases (bone tunnel: 24 cases; OTTR method: 30 cases) and double in 24 cases (bone tunnel: 16 cases; OTTR for AM bundle and bone tunnel for PL bundle: eight cases). The cause of re-injury, the meniscus and cartilage injury, the reconstruction method, and the Lysholm score, Lachman test, Pivot-shift test, and the side-to-side difference in the tibial anterior translation were evaluated before and after surgery.

Results

There was no statistically significant difference in the Lyshom score, Lachman / Pivotshift test and side-to-side difference anterior translation of the tibia between the four groups.

Conclusions

The clinical results of single and double OTTR revision ACLR are equivalent to those of anatomic single and double bone tunnel procedures.

The therapeutic capacity of bone marrow MSC-derived extracellular vesicles in Achilles tendon healing is passage dependent and indicated by specific glycans

The therapeutic potential of mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) for various diseases and tissue repair is attracting attention. Here, EVs from conditioned medium of human bone marrow MSCs at passage 5 (P5) and 12 (P12) were analyzed using mouse Achilles tendon rupture model and lectin microarray. P5 MSC-EVs accelerated Achilles tendon healing compared with P12 MSC-EVs. Fucose-specific lectin TJA-II was indicated as a glycan marker for therapeutic MSC-EVs. The present study demonstrated that early passaged MSC-EVs promote Achilles tendon healing compared with senescent MSC-EVs. Glycans on MSC-EVs might provide useful tools to establish a quality control and isolation system for therapeutic MSC-EVs in regenerative medicine.

Current status of countermeasures for ageing of nuclear power plants in Japan

This paper summarizes ageing countermeasure program of the nuclear power plants performed by the Japanese Government and industries and related activities, and describes current research program and utilization of the research results for the aged nuclear power plants. Regulatory bodies (NISA of METI: Nuclear and Industrial Safety Agency of the Ministry of Economy, Trade and Industry') reviewed the ageing issues of nuclear power plants to enhance countermeasures for the aged plants. Nuclear Power Plant Life Engineering Center (PLEC) entrusted by NISA is carrying out the task relating to the aged plants.

A Comparison of Central Anatomic Single-Bundle Reconstruction and Anatomic Double-Bundle Reconstruction in Anteroposterior and Rotational Knee Stability: Intraoperative Biomechanical Evaluation

Postoperative anterior and rotational stability are still controversial when compared with single-bundle (SB) and double-bundle (DB) anterior cruciate ligament (ACL) reconstruction. This study aimed to compare the central anatomical SB and anatomical DB ACL reconstruction in intraoperative knee kinematics during continuous knee flexion-extension. A total of 34 patients who underwent ACL reconstruction using the hamstring tendon were evaluated intraoperatively before and immediately after ACL reconstruction using OrthoPilot ACL Navigation System Version 3.0. The patients were prospectively randomized into the central anatomical SB (17 knees) and the anatomical DB reconstruction (17 knees) groups. The tibial translation and rotation were continuously measured during knee flexion-extension under conventional knee motion, anterior tibial load (100N), and internal-external torque (3 N·m). The anterior tibial translation and total range of tibial rotation were calculated from the measurement values from 20 to 50 degrees at each 5-degree point. The anterior tibial translation (p = 0.59; two-factor repeated measures analysis of variance; η ²G = 0.0077) and total range of tibial rotation (p = 0.95; η ²G = 0.0001) at each knee flexion angle showed no significant difference between the central anatomical SB and anatomical DB reconstruction groups. It is suggested that the central anatomical SB reconstruction is comparable with the anatomical DB reconstruction in biomechanical anteroposterior and rotational knee stability at time 0.

PD-1 blockade therapy promotes infiltration of tumor-attacking exhausted T cell clonotypes

PD-1 blockade exerts clinical efficacy against various types of cancer by reinvigorating T cells that directly attack tumor cells (tumor-specific T cells) in the tumor microenvironment (TME), and tumor-infiltrating lymphocytes (TILs) also comprise nonspecific bystander T cells. Here, using single-cell sequencing, we show that TILs include skewed T cell clonotypes, which are characterized by exhaustion (T_ex) or nonexhaustion signatures (T_non-ex). Among skewed clonotypes, those in the T_ex, but not those in the T_non-ex, cluster respond to autologous tumor cell lines. After PD-1 blockade, non-preexisting tumor-specific clonotypes in the T_ex cluster appear in the TME. Tumor-draining lymph nodes (TDLNs) without metastasis harbor a considerable number of such clonotypes, whereas these clonotypes are rarely detected in peripheral blood. We propose that tumor-infiltrating skewed T cell clonotypes with an exhausted phenotype directly attack tumor cells and that PD-1 blockade can promote infiltration of such T_ex clonotypes, mainly from TDLNs.

Long working hours, depression and suicidality among OB/GYNs in Japan

Background

There is abundant evidence linking long working hours among physicians with adverse health effects; however, most studies have focused on medical residents. In Japan, obstetrician/gynaecologists (OB/GYNs) work the longest hours, yet no studies have investigated potential relationships between excessive overtime and depression and suicidal ideation within this population.

Aims

To investigate the relationship between long working hours and depression and suicidal ideation among OB/GYNs in Japan.

Methods

We administered a survey questionnaire to OB/GYNs and received 919 valid responses. Multivariate logistic regression was performed with depression and suicidal ideation as the outcome variables and number of working hours per week, gender, age, marital status, hospital type and geographical area type as the explanatory variables.

Results

Sixteen per cent of the participants were depressed, and 3% reported suicidal ideation. Working 100 or more hours per week increased the odds for both depression and suicidal ideation [odds ratio (OR): 2.08 (95% confidence interval {CI}: 1.07–4.05, P = 0.03); and OR: 7.03 (95% CI: 1.95–25.38, P &lt; 0.001), respectively].

Conclusions

The results suggest that the Japanese Government should vigorously promote physicians’ work-style reform, so that a lowered upper limit of overtime hours will be enforced from 2024 to improve physicians’ health and patients’ safety.

Application of a true lateral virtual radiograph from 3D-CT to identify the femoral reference point of the medial patellofemoral ligament

PURPOSE

The purpose of this study is two-fold: (1) to describe the femoral reference point of the medial patellofemoral ligament (MPFL) on a virtual true lateral radiograph reconstructed from a three-dimensional computed tomography (3D-CT) image and (2) to compare this point with that of patients without patellofemoral instability and with Schöttle's point.

METHODS

A total of 26 consecutive patients (29 affected knees) with recurrent patellar dislocation (RPD), who underwent MPFL reconstruction were included in this study (4 males; 22 females; mean age, 24.0 years old). Using a true lateral 3DCT image, the MPFL femoral insertion was identified and marked with a 2-mm circle, and this image was reconstructed as a virtual true lateral radiograph. Following Schöttle's method, the point of intersection was described by their anterior-posterior and proximal-distal positions. As a control population, 29 age- and gender-matched patients with anterior cruciate ligament (ACL) injuries were also analysed.

RESULTS

The points in RPD patients were located significantly posterior (-2.5 ± 2.3 mm, p < 0.01) to the line representing an extension of the posterior cortex of the femur and distal (- 6.9 ± 2.4 mm, p < 0.01) to the posterior origin of the medial femoral condyle compared with those in the control population. The mean reference point of RPD patients was located in a 3.8-mm posterior and 4.4-mm distal position compared with Schöttle's point.

CONCLUSIONS

An anatomical and radiographic femoral reference point of the MPFL on a true lateral virtual radiograph was described with our method. In patients with RPD, this reference point was identified to be more posterior and distal to Schöttle's point. More anatomical and individualized MPFL reconstruction will be secured using our method.

LEVEL OF EVIDENCE

Level IV.

Quantitative evaluation of abnormal finger movements in myelopathy hand during the grip and release test using gyro sensors

Previous studies have reported qualitative characteristics of myelopathy hand, but few studies have reported quantitative kinematic parameters of this condition. Our purpose of this study was to quantitatively evaluate the abnormal finger movements in patients with cervical compressive myelopathy (CCM) (termed myelopathy hand) and to understand the characteristics of myelopathy hand during the grip and release test (GRT) using gyro sensors. Sixty patients with CCM (severe: n = 30; mild-to-moderate: n = 30) and sixty healthy adults (age-matched control: n = 30; young control: n = 30) were included in this study. All participants performed the GRT. The index and little fingers’ and the wrist’s movements during the GRT were recorded using three gyro sensors. The number of cycles, switching time-delay, time per cycle, and peak angular velocity were calculated and compared between groups. Patients with severe CCM had the lowest number of cycles and longest switching time-delays, followed by patients with mild-to-moderate CCM, the age-matched control group, and the young control group. The time per cycle and the peak angular velocities of fingers in participants with severe CCM were significantly lower than those in participants with mild-to-moderate CCM; however, there were no significant differences between the control groups. The peak angular velocities of fingers were significantly lower during extension motions than during flexion motions in participants with CCM. Participants with CCM have lower peak angular velocities during finger movement. Finger extension also is impaired in participants with CCM. Abnormal finger movements and the severity of myelopathy in participants with CCM can be assessed using gyro sensors.

Therapeutic effect of targeting Substance P on the progression of osteoarthritis

OBJECTIVES

Substance P (SP) modulates NK1 and has various functions such as regulation of pain response, bone metabolism, and angiogenesis, which are recognized as important factors in osteoarthritis (OA). We aimed to evaluate the therapeutic effect of targeting SP on OA progression.

METHODS

SP expression patterns were analysed histologically in articular cartilage and subchondral bone of human knees from OA patients and autopsy donors as non-OA samples and in mouse articular cartilage. Moreover, to examine the effect of SP on the progression of OA, we administered drugs to mice following the surgical destabilization of the medial meniscus: Phosphate-buffered saline (PBS), septide (NK1 receptor agonist), or aprepitant (NK1 receptor antagonist). Histological analysis and bone morphologic analysis using micro-computed tomography were performed.

RESULTS

In human analysis, the expression of SP in mild OA samples was significantly higher than that in severe OA, and that in healthy cartilage was significantly higher than that in OA. In mouse analysis, Osteoarthritis Research Society International scores in the septide group were significantly lower than those in the control group. Computed tomography analysis showed that the subchondral bone's epiphysis in the control group had sclerotic change, not observed in the septide group.

CONCLUSIONS

The administration of septide ameliorates OA progression through preventing subchondral bone sclerosis.