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Megalin, a type I transmembrane protein, serves as a multi-ligand endocytic receptor in the apical membrane of proximal tubules. Its ectodomain and full-length forms are excreted into human urine, with the former being more abundant. We previously developed two types of sandwich enzyme-linked immunosorbent assays (ELISAs) utilizing monoclonal antibodies that target the amino-terminal ligand-binding domain-I and the carboxyl-terminal cytoplasmic region of human megalin, respectively. The former, termed "A-megalin" ELISA, primarily identifies ectodomains of megalin, whereas the latter, "C-megalin" ELISA, specifically recognizes full-length megalin originating from urinary extracellular vesicles. This study developed novel sandwich ELISAs to assess mouse urinary A-megalin and C-megalin, thereby facilitating studies involving these biomarkers in mouse disease models. Immunoblotting and immunohistochemistry of monoclonal antibodies against human megalin were performed to assess their compatibility with mouse megalin in novel sandwich ELISAs, which were constructed and validated using human assay protocols. Immunoblot analysis of megalin in urinary extracellular vesicles and supernatant was performed to investigate the ratio of ectodomain to full-length forms in mouse urine. Stable measurements having a precision and accuracy within 15 % were achieved in the measurement of quality control samples. A-megalin and C-megalin were detectable in the urine of C57BL/6 mice, whereas most urine samples from kidney-specific conditional megalin-knockout mice were below detection limits. Ectodomain forms of megalin were at least approximately 70 times more abundant than the full-length form, even in mouse urine. In conclusion, we successfully developed sandwich ELISAs for assessing mouse urinary A-megalin and C-megalin to evaluate primarily ectodomain and full-length forms of megalin, respectively., Competing Interests: Declaration of competing interest A.S. received research grants from Denka Co., Ltd., (Copyright © 2024. Published by Elsevier B.V.)

Background and Objective: The dynamic characteristics of the intact knee joint are valuable for treating knee osteoarthritis and designing knee prostheses. However, it remains a challenge to elucidate the detailed dynamics of the knee due to its complexity of anatomical structure and complex interaction with body dynamics., Methods: In this study, a unique subject-specific musculoskeletal model with a concurrent high-accuracy intact finite element knee model was created and used to simultaneously evaluate the kinematics and mechanics of an intact knee joint during the gait cycle., Results: A medial pivot motion with external rotation, and a large parallel anterior translation were observed in the stance and swing phases, respectively, which is consistent with the in vivo fluoroscopy measurements. The maximum axial contact force on the knee joint, observed at 45% of the gait cycle, is approximately 2.89 times the body weight. The medial cartilage bears 65.7% of the total axial contact force. The results demonstrate that the cartilage-cartilage contact bears most of the joint load (62.5%) compared to the cartilage-meniscus-cartilage contact (37.5%). Regarding contact mechanics, the maximum contact pressure on both sides of the tibial cartilage (8.2 MPa) is almost similar to the first axial loading peak (14%) of the gait cycle. Additionally, the maximum contact pressure (6.01 MPa) was observed during the stance phase of the gait cycle on the patellofemoral joint., Conclusions: The predicted results on the tibiofemoral and patellofemoral joints provide a theoretical basis for the treatment of knee joint diseases and knee prosthesis design. Moreover, this approach presents a comprehensive tool to evaluate the mechanics at both the body and tissue levels. Therefore, it has a high potential for application in human biomechanics., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Bone drilling is an indispensable and demanding operation among many orthopaedic operations. A dedicated drill bit that can achieve low-trauma and self-centring drilling is in urgent need. In this study, a three-step orthopaedic low-traumatic drill bit design was proposed. In order to evaluate the drilling performance of the proposed drill, comprehensive comparison tests were carried out with various commercial medical drills in terms of skiving force, thrust force, temperature rise, and surface quality. The experimental results show that the proposed three-step drill design with the optimal point angle, a small chisel edge, transition arc and web thinning can obtain lower and more stable thrust force, slighter bending force, smaller temperature rise, and higher hole quality compared with the commercial drill bits. The proposed drill shows satisfactory drilling performance and has great application potential in clinical surgery., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background and Objective: A computational knee model facilitates efficient component design evaluations and preclinical testing under various dynamic loadings. However, the development of a highly mimicked dynamic whole knee model with specified ligament constraints that provides high predictive accuracy with in-vivo experiments remains a challenge., Methods: In the present study, a musculoskeletal integrated force-driven explicit finite-element knee model with tibiofemoral and patellofemoral joints constrained with detailed soft tissue was developed. A proportional-integral-derivative controller was concurrently added to the knee model to track the boundary conditions. The actuations of the quadriceps and hamstrings were predicted via a subject-specific musculoskeletal model and matched with electromyography results., Results: Compared to in-vivo fluoroscopic results in a gait cycle, the predicted results of the kinematics of the tibiofemoral joint exhibited an agreement in terms of tendency and magnitude (anterior-posterior translation: RMSE = 1.1 mm, r 2  = 0.87; inferior-superior translation: RMSE = 0.83 mm, r 2  = 0.84; medial-lateral translation: RMSE = 0.82 mm, r 2  = 0.05; flexion-extension rotation: RMSE = 0.23°, r 2  = 1; internal-external rotation: RMSE = 1.85°, r 2  = 0.65; varus-valgus rotation: RMSE = 1.39°, r 2  = 0.08). Contact mechanics, including the contact area, pressure, and stress, were synchronously simulated on the tibiofemoral and patellofemoral joints., Conclusions: The study provides a calibrated knee model and a kinematical validation approach that can be widely used in preclinical testing and knee prosthesis design., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Bone cutting with high efficiency as well as low levels of forces and damage has a great significance for orthopaedic surgeries. Due to the brittleness and anisotropy of cortical bone, a conventional cutting process can cause irregular crack propagation and fractured bone chip, affecting the tissue removal process and postoperative recovery. In this paper, a high-frequency impact cutting method is investigated, and its effect on fracture propagation, chip formation and cutting forces is studied for orthogonal cutting. Experimental results show that cracks are deflected by cement lines in conventional cutting, forming fractured blocks or split chips. In impact cutting, the cutting-induced fractures expand along a main shear direction, generating small pieces of triangular segmented chips. Cutting forces are significantly reduced with vibration-induced impacts; especially, the main cutting force is nearly 70% lower than that in the conventional cutting. The main reason for this is much higher strain rates in high-frequency impact cutting than in a conventional process, and direct penetration of fractures across the osteonal matrix without deflections along the cement lines. This results in a straighter path along the main shear plane and totally different chip morphology; so, a lower consumption of cutting energy in the main shear direction reduces the macroscopic cutting force. The results of this study have an important theoretical and practical value for revealing the mechanism of impact cutting, improving the efficiency of osteotomy and supporting the innovation in bone surgical instruments., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Analysis: of a mechanism of bone cutting has an important theoretical and practical significance for orthopaedic surgeries. In this study, the mechanism of material removal in orthogonal cutting of cortical bone is investigated. Chip morphology and crack propagation in cortical bone for various cutting directions and depth-of-cut (DOC) levels are analysed, with consideration of microstructural and sub-microstructural features and material anisotropy. Effects of different material properties of osteons, interstitial matrix and cement lines on chip morphology and crack propagation are elucidated for different cutting directions. This study revealed that differences in chip morphology for various DOCs were due to comparable sizes of the osteons, lamellae and DOC. Acquired force signals and recorded high-speed videos revealed the reasons of fluctuations of dynamic components in tests. Meanwhile, a frequency-domain analysis of force signals showed a frequency difference between formation of a bulk fractured chip and small debris for different cutting directions. In addition, SEM images of the top and side surfaces of the machined bone were obtained. Thus, the analysis of the cutting force and surface damage validated the character of chip formation and explained the material-removal mechanism. This study reveals the mechanism of chip formation in the orthogonal cutting of the cortical bone, demonstrating importance of the correlation between the chip morphologies, the depth of cut and the microstructure and sub-microstructure of the cortical bone. For the first time, it assessed the fluctuations of cutting forces, accompanying chip formation, in time and frequency domains. These findings provide fundamental information important for analysis of cutting-induced damage of the bone tissue, optimization of the cutting process and clinical applications of orthopaedic instruments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Bone is a natural composite and its cutting is a common procedure in orthopedic surgery. The processing damage, cutting force, and cutting heat strongly influence postoperative recovery. In this study, a orthogonal elliptical vibration-assisted (EVA) bone cutting system is developed based on semi-brittle behaviors of bone to experimentally investigate fracture, cutting force, roughness and temperature rise. To prevent large-scale fractures during bone cutting, an extended finite element method model incorporating detailed microstructure and material properties of bone is created to understand the crack-propagation mechanism. Both the simulation and the experiments demonstrate that the elliptical vibration could effectively control the direction of crack propagation. The experimental results also demonstrate that the cutting force and surface roughness decreases with an increase in the vibration frequency or amplitude, whereas temperature rise increases with the vibration frequency. These findings prove that the EVA could allow for low-trauma bone cutting in orthopedic surgery., Competing Interests: Declaration of competing interest None declared., (Copyright © 2019. Published by Elsevier Ltd.)

Background: A total knee arthroplasty should restore the mechanical function of the knee and enable patients to perform desired daily activities. The joint kinematics and contact mechanics performance are important determinants of the success of total knee arthroplasty devices. The purpose of this study was to determine the effect of intercondylar sagittal conformity on kinematics and contact mechanics., Methods: An explicit dynamic finite element method was used to investigate the differences in the performances of constrained cruciate-retaining (CR), unconstrained CR, and medial pivot designs during gait, squatting, descending stairs, and climbing stairs. The predicted kinematic results were verified through an in vitro experiment during the gait cycle., Results: The results confirmed that the medial pivot design improved the kinematic behavior with no paradoxical anterior motion, which was found in the unconstrained prosthesis during the four activities. However, a small femoral internal rotation was found during gait (3.9°), descending stairs (2.2°), and climbing stairs (3.6°), which may produce anterolateral pain. An enlarged contact area and a lower peak contact pressure were observed on the medial side of the medial pivot prosthesis. Conversely, on the lateral side of the medial pivot prosthesis, the contact area and peak contact pressure were equal to those of the unconstrained prosthesis, which could potentially result in wear., Conclusion: In summary, although the medial pivot prosthesis may provide qualitatively similar kinematics as the average measurements of tibiofemoral motion, further in vivo analysis and long-term studies on the femoral internal rotation and high contact pressure on the lateral side are still required., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Objective: Umbilical cord entanglement is known to be a major cause of fetal hypoxia and to be correlated with several neonatal complications, but almost all of the previous reports were restricted to nuchal cord. In this study, we retrospectively examined the correlation between multiple part cord entanglement and pregnancy outcomes., Materials and Methods: A total of 2156 cases were recruited from term deliveries in our hospital from 2008 to 2012. We counted umbilical cord loop numbers not only for nuchal cord but also for trunk and limb cord entanglement. We classified the cases into three groups: no loop, single loop and multiple loops group. We statistically analyzed pregnancy outcomes statistically in the three groups., Results: One thousand, four hundred and fifty-eight cases had no cord entanglement, 594 cases had single loop entanglement and 104 cases had multiple loops entanglement. Values of umbilical artery blood, pH (p = 0.002) and base excess (p < 0.001) showed significantly unfavorable status in entanglement cases, especially in the multiple loops group. A significantly larger percentage of neonates in the multiple loops group needed for oxygen (p < 0.001)., Conclusion: Multiple umbilical cord entanglement is highly correlated with early neonatal unfavorable status and need for resuscitation., (Copyright © 2018. Published by Elsevier B.V.)

Objectives: Most methods currently used to assess surgical skill are rather subjective or not adequate for microneurosurgery. Objective and quantitative microneurosurgical skill assessment systems that are capable of accurate measurements are necessary for the further development of microneurosurgery., Methods: Infrared optical motion tracking markers, an inertial measurement unit, and strain gauges were mounted on tweezers to measure many parameters related to instrument manipulation. We then recorded the activity of 23 neurosurgeons. The task completion time, tool path, and needle-gripping force were evaluated for three stitches made in an anastomosis of 0.7-mm artificial blood vessels. Videos of the activity were evaluated by three blinded expert surgeons., Results: Surgeons who had recently done many bypass procedures demonstrated better skills. These skilled surgeons performed the anastomosis with in a shorter time, with a shorter tool path, and with a lesser force when extracting the needle., Conclusions: These results show the potential contribution of the system to microsurgical skill assessment. Quantitative and detailed analysis of surgical tasks helps surgeons better understand the key features of the required skills., (Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Assessment of the radial pulse by palpation (pulse diagnosis) is an important diagnostic technique in Traditional Chinese Medicine (TCM), but the changes of blood flow volume in the radial artery during and after acupuncture are unknown., Objective: The aim of this study was to explore the changes of radial artery blood flow volume during and after acupuncture in healthy subjects., Design: This study was conducted as a pilot study utilizing a one-group intervention design., Setting: The study was conducted at a TCM outpatient clinic of Tohoku University Hospital., Participants: Twenty-six healthy volunteers participated in the study., Intervention: Acupuncture was performed at LR-3 bilaterally with manual rotation of the needles., Outcome Measures: Blood pressure was measured at rest and 180 seconds after acupuncture. Radial artery hemodynamics were monitored continuously with a high-resolution ultrasound echo-tracking system. The vessel diameter and blood flow volume of the right radial artery and heart rate were measured at rest, before acupuncture, during acupuncture, and 30, 60, and 180 seconds after acupuncture., Results: The systolic and diastolic diameter of the radial artery did not significantly change. Radial artery blood flow volume decreased significantly during acupuncture (mean +/- SD, 0.16 +/- 0.11 mL/sec per m(2); P < .01) compared with baseline (0.43 +/- 0.27 mL/sec per m(2)), but was increased at 180 seconds after acupuncture (0.54 +/- 0.28 mL/sec per m(2); P < .01)., Conclusions: The present study showed that radial artery blood flow volume decreased immediately during acupuncture at the LR-3 acupoint, but was increased at 180 seconds after acupuncture.

Purpose: To develop a prototype robotic system designed to assist vitreoretinal surgery and to evaluate its accuracy and maneuverability., Design: Experimental study., Participants: This study used harvested porcine eyes., Methods: After development of a prototype robotic system, pointing accuracy tests of the system were performed on graph paper and in harvested porcine eyes. The average maximal deviation from the aiming point to the actual position of the tip of the instrument was compared between manually conducted procedures and those conducted with robotic assistance. The feasibility of creating posterior vitreous detachment (PVD), retinal vessel sheathotomy (RVS), and retinal vessel microcannulation also were evaluated in porcine eye models, and the success rates of 4 consecutive attempts for each kind of procedure were evaluated., Main Outcome Measures: The average maximum deviation in pointing accuracy tests both on graph paper and in animal eye models was a main outcome measure. The success rate of making PVD, RVS, and retinal vessel microcannulation was the other primary outcome measure., Results: The pointing accuracy was superior with robotic assistance both on graph paper (327.0 microm vs. 32.3 microm) and in animal eye models (140.8 microm vs. 33.5 microm). Creating PVD, RVS, and retinal vessel microcannulation was feasible in 4 of 4 attempts, 4 of 4 attempts, and 2 of 4 attempts, respectively. The 2 failures in microcannulation were considered to be the result of difficulty in visual differentiation between the retinal vessel and retina in harvested porcine eyes., Conclusions: Improved accuracy and desirable feasibility of a prototype robotic system to assist vitreoretinal surgery were shown in this study. Research for wider implementation of robot-assisted surgery should be continued; there are some hurdles to overcome.

We describe the cloning and characterization of Siglec-H, a novel murine CD33-related siglec-like molecule with 2 immunoglobulin domains. Unlike other CD33-related siglecs, Siglec-H lacks tyrosine-based signaling motifs in its cytoplasmic tail. Although Siglec-H has the typical structural features required for sialic acid binding, no evidence for carbohydrate recognition was obtained. Specific monoclonal and polyclonal antibodies (Abs) were raised to Siglec-H and used to define its cellular expression pattern and functional properties. By flow cytometry, Siglec-H was expressed specifically on plasmacytoid dendritic cell (pDC) precursors in bone marrow, spleen, blood, and lymph nodes. Staining of tissue sections showed that Siglec-H was also expressed in a subset of marginal zone macrophages in the spleen and in medullary macrophages in lymph nodes. Using bone marrow-derived pDC precursors that express Siglec-H, addition of Abs did not influence cytokine production, either in the presence or absence of synthetic oligodeoxynucleotides containing unmethylated cytosine-guanine motifs (CpG). In comparison, Siglec-H functioned as an endocytic receptor and mediated efficient internalization of anti-Siglec-H Abs. By immunizing mice with ovalbumin-conjugated anti-Siglec-H Ab in the presence of CpG, we demonstrate generation of antigen-specific CD8 T cells in vivo. Targeting Siglec-H may therefore be a useful way of delivering antigens to pDC precursors for cross-presentation.

Leukocyte IgG receptors (Fc gamma R) are important immune-response modulating molecules. Fc gamma RIIIa is expressed on macrophages, NK-cells and gamma delta-T cells and exhibits a genetically determined, functional polymorphism at nucleotide 559. This allelic difference predicts either a phenylalanine (F158) or valine (V158) at amino acid 158 in the membrane-proximal extracellular domain, and has been shown to be associated with autoimmune and infectious diseases. Published methods to determine Fc gamma RIIIa genotypes are cumbersome. Therefore, we developed a novel, rapid and reliable PCR-based method to determine Fc gamma RIIIa genotypes. Comparison of genotyping results with direct Fc gamma RIIIa sequencing of 60 blood donors showed 100% accuracy of this new method. Since genotype frequencies of Fc gamma R polymorphisms depend strongly on race and ethnicity, we compared Fc gamma RIIIa genotype frequencies of 176 Caucasian Dutch and 104 Japanese blood donors. Interestingly, these frequencies were not significantly different (P>0.1), in contrast to the Fc gamma RIIa and Fc gamma RIIIb genotype frequencies (P<0.001).

To assess the influence of environmental cadmium (Cd) exposure on long-term outcome, a follow-up study was conducted from 1981-1982 to March 1991 on 3178 inhabitants living in the Cd-polluted Kakehashi River basin. The standardized mortality ratios of the urinary beta 2-microglobulin (beta 2-MG)-, protein-, and amino acid-positive subjects of both sexes and the urinary glucose-positive female subjects were higher than those of the subjects with urinary-negative findings or the general Japanese population during the observation period. After adjusting for age using Cox's proportional hazards model, significant associations were found between mortality and urinary indices. In multiple comparisons using all of the indices, urinary protein and beta 2-MG in the women and urinary protein in the men were the factors most contributing to the mortality rates. In the urinary protein-negative female group as well, a significant association was found between urinary beta 2-MG and mortality. These results suggest that the prognosis of subjects with Cd-induced renal dysfunction is unfavorable, with the mortality rate increasing even in the early stage of proximal tubular dysfunction. Urinary protein and urinary beta 2-MG are important prognostic factors, with the latter, in particular, considered to be useful as an early index predictive of premature mortality.

The extraction behaviour of tellurium(IV) and tellurium(VI) with sodium diethyldithiocarbamate, ammonium pyrrolidinedithiocarbamate and dithizone in organic solvents has been investigated by means of flameless atomic-absorption spectrophotometry with a carbon-tube atomizer. The selective extraction of tellurium(IV) and differential determination of tellurium(IV) and tellurium(VI) have been developed. With sodium diethyldithiocarbamate and carbon tetrachloride, when the aqueous phase/organic solvent volume-ratio is 5 and the injection volume in the carbon tube is 20 microl, the sensitivity for tellurium is 0.3 ng/ml for 1% absorption. The relative standard deviations are ca. 2%. The proposed methods have been applied satisfactorily to determination of tellurium(IV) and tellurium(VI) in various types of water.

A fluorometric liquid chromatographic method was developed for measurements of unconjugated oestradiol and oestriol in the serum of pregnant women. The serum samples are injected directly into the apparatus and pass to a pretreatment column, where oestrogens are adsorbed while hydrophilic components such as proteins and carbohydrates are not. The oestrogens then pass into a separation column containing a new type of polymer gel. The mobile phase consists of an acetonitrile-water mixture, and separation is achieved by a reversed-phase mechanism. The eluent is monitored for fluorescence. Data on the reproducibility and recovery by this method and the correlation of values with those obtained by radioimmunoassay are reported. Results on the increases of oestradiol and oestriol in the serum during pregnancy are also reported.