Effects of abdominal hollowing and bracing on each intervertebral angle during quadruped upper and lower extremity lift: Three-dimensional motion analysis of the spine.

To investigate the effects of intentionally minimizing spinal motion and abdominal muscle contractions on intervertebral angles during quadruped upper and lower extremity lift (QULEL). Fifteen healthy men performed the QULEL under four conditions: without any special instructions (basic), with the intention to minimize spinal motion (intentional), with abdominal bracing (bracing), and with abdominal hollowing (hollowing). Each intervertebral angle was calculated from the local coordinate system using the marker data obtained from a motion capture system. Shear moduli, as indicators of the activities of the right transversus abdominis (TrA), internal and external oblique, and rectus abdominis muscles, were assessed using shear wave elastography during QULEL. One-way repeated-measures analysis of variance and multiple comparisons among conditions were used to compare each shear modulus of the abdominal muscle and the changes in thoracic kyphosis (Th1-12), lumbar lordosis (L1-5), and lumbar intervertebral angles from the quadruped position to QULEL. The significance level was set at P < 0.05. Changes in lumbar lordosis and L2/L3 and L3/L4 extension angles were significantly lower under hollowing than under other conditions (effect size ηG2: lumbar lordosis, 0.068; L2/L3, 0.072; L3/L4, 0.043). The change in the L1/L2 extension angle significantly decreased in bracing and hollowing compared with the basic (ηG2 = 0.070). Only the TrA shear modulus significantly increased in bracing and hollowing compared with the basic (ηG2 = 0.146). Abdominal hollowing during the QULEL increased TrA activity and suppressed lumbar extension, except at L4/L5, and may be more effective as a rehabilitation exercise for controlling spinal motion.

Effect of age on shear modulus, muscle thickness, echo intensity of the upper limb, lower limb, and trunk muscles in healthy women.

PURPOSE: This study aimed to examine the effect of age on the mechanical properties, muscle size, and muscle quality in the upper and lower limb and trunk muscles. METHODS: We evaluated the shear modulus (G), muscle thickness (MT), and echo intensity (EI) of the upper and lower limb and trunk muscles of 83 healthy women (21-83-year-old). The G values of some limb muscles were measured in relaxed and stretched positions. RESULTS: Regarding the effect of age on G at the distinct positions, the G of the upper limb muscles were not significantly correlated with age in the relaxed and stretched positions. In contrast, the G of the iliacus showed a significant negative correlation in both positions. Additionally, the G of the rectus femoris had a significant negative correlation only in the relaxed position. Regarding differences among body parts, the G of the lower limb and oblique abdominal muscles showed a significant negative correlation, but no correlation in the upper limb, rectus abdominis, and back muscles. Moreover, MT showed a significant negative correlation with age in the lower limb, abdominal, and erector spinae muscles, but no correlation was detected in the upper limb and lumbar multifidus muscles. EI had a significant positive correlation in all the muscles. CONCLUSION: The effect of age on G depended on body parts, and the G of the lower limb and oblique abdominal muscles negatively associated with age. Additionally, G in the relaxed position may be more susceptible to aging than G in the stretched position.

Validity of the frame subtraction method in dynamic postural stability.

BACKGROUND: The movement of targeted subjects can be calculated using the frame subtraction method. However, the validity of this evaluation method of dynamic postural stability has not been clarified yet. This study aimed to verify the validity of the evaluation method for jump landing using the frame subtraction score based on the ground reaction force (GRF). METHODS: Twenty subjects performed single-leg jump landing, and their dynamic postural stability index (DPSI), medial‒lateral stability index (MLSI), anterior‒posterior stability index, and vertical stability index (VSI) were calculated from the GRF. Simultaneously, motion images were captured using digital video cameras in the sagittal and frontal planes. After the motion images were analyzed using the frame subtraction method, the frame subtraction scores in the frontal, sagittal, and combined planes were calculated. To confirm its validity, the relationship between the frame subtraction scores and GRF parameters was investigated using Pearson's correlation analysis. RESULTS: The frame subtraction scores in the frontal and combined planes were significantly correlated with the DPSI, MLSI, and VSI (r = 0.46-0.75, P < 0.05). CONCLUSIONS: Therefore, the frame subtraction method could be applied to the evaluation of dynamic postural stability. Markerless systems are deemed useful in clinical practice.

Differences in shear elastic modulus of the latissimus dorsi muscle during stretching among varied trunk positions.

The latissimus dorsi (LD) can be divided into the upper, middle, and lower parts, but the effective stretching positions for each part are unknown. In this study, we aimed to investigate effective trunk positions for stretching of the LD. A total of 14 healthy males participated in this study. The following seven trunk positions were chosen as the LD stretching positions; upright of the trunk (Baseline), flexion of the trunk (Flex), contralateral bending of the trunk (LB), contralateral rotation of the trunk (Rot), flexion and contralateral bending of the trunk (Flex + LB), flexion and contralateral rotation of the trunk (Flex + Rot), and contralateral bending and contralateral rotation of the trunk (LB + Rot). Maximal elevation of the upper limb was passively added to all positions. The shear elastic modulus, used as the index of muscle elongation, was measured at the four parts (upper, middle, lower, distal parts) of the LD. The shear elastic moduli showed obviously high values in Rot and LB + Rot at the upper, middle, and distal parts, and also in LB, Rot, and LB + Rot at the lower part. These findings suggest that contralateral trunk rotation, or a combination of contralateral trunk bending and rotation are effective trunk positions for stretching all parts of the LD. Contralateral trunk bending was also effective for stretching the lower part of the LD.

Verification of validity of gait analysis systems during treadmill walking and running using human pose tracking algorithm.

BACKGROUND: The human tracking algorithm called OpenPose can detect joint points and measure segment and joint angles. However, the validity of gait analysis using OpenPose has not been examined yet. RESEARCH QUESTION: What is the validity of OpenPose-based gait analysis? METHODS: Twenty-four healthy young people participated in this study. The participants were assessed during walking and running. Pelvic segment angles, and hip, knee, and ankle joint angles during treadmill walking and running were measured using VICON. Simultaneously, images were captured using digital cameras from the right and back sides. After processing with OpenPose, the corresponding angles were measured from the estimated joint points. To validate these estimations, linear regression analysis was performed, and intraclass correlation coefficients [ICCs (2, 1)] between the data obtained by OpenPose and VICON were calculated. Furthermore, the agreement between the data obtained by OpenPose and VICON was assessed by Bland-Altman analysis. RESULTS: For most ranges of motion (ROM) in the sagittal plane, the hip, knee, and ankle joints had large coefficients of determination, without proportional biases. For most peak angles in the sagittal plane, the knee and ankle joints had large coefficients of determination without proportional biases, although the hip joint had nonsignificant coefficients of determination and proportional biases. In particular, for the hip flexion-extension ROM and peak knee flexion angle during running and the knee ROM during slow walking, the ICCs showed good to excellent agreement. However, for the parameters of the pelvis and hip joint in the frontal plane, there were nonsignificant coefficients of determination and poor ICCs with fixed and proportional biases. SIGNIFICANCE: The lower limb ROM in the sagittal plane during gait can be measured by the OpenPose-based motion analysis system. The markerless systems have the advantage of being more economical and convenient than conventional methods.

Verification of criterion-related validity of the evaluation method of postural stability using the frame subtraction method.

It is important to quantify the postural stability. The frame subtraction method can calculate the motions of a subject, and might be easier to implement, with lower costs. However, validity of the evaluation of postural stability using this method have not been validated yet. Therefore, the purpose of this study was to verify criterion-related validity of the frame subtraction scores and the center of pressure (COP) parameters during maintenance of single leg standing. Twenty two healthy young subjects participated in this study. Motion tasks comprised right leg standing with eyes open and closed. The total length of COP displacements (LNG), Root mean square (RMS) area, anterior - posterior (AP) range, medial - lateral (ML) range were recorded using the force plate. Simultaneously, the motion images were acquired with digital video cameras from the front and right sides. After the motion images were analyzed using the frame subtraction method, the frame subtraction scores (maximum / sum of the frame subtraction score on each plane / the frontal and sagittal planes) were measured. To confirm the validity, Spearman's rank correlation coefficient between the frame subtraction scores and the COP parameters was calculated. The sum of the frame subtraction score on the frontal plane was significantly correlated with all COP displacements in the single leg standing. The result of this study indicated that the frame subtraction method could be applied to the evaluation of balance task with postural sway such as maintenance of single leg standing. The frame subtraction method is low cost and easy owing to its marker-less systems.

Age-related changes in muscle thickness and echo intensity of trunk muscles in healthy women: comparison of 20-60s age groups.

PURPOSE: The objective of this study was to investigate the age-related changes in muscle thickness and muscle echo intensity of trunk in subjects including wide range of age groups. METHODS: The subjects were 112 healthy women (age range 20-60s). The rectus abdominis, external oblique, internal oblique, transversus abdominis, erector spinae, and lumbar multifidus muscles were examined. To confirm the differences among the age groups, the linear mixed effect models were performed. RESULTS: There were significant decreases in muscle thickness of the rectus abdominis and external oblique muscles in the 50s and 60s age groups compared to those in the 20s age group, and a significant decrease in muscle thickness of the erector spinae muscle in the 60s age group compared to those in the 20s age group. However, there was no significant difference among the age groups in muscle thickness of other trunk muscles. There were significant increases in echo intensity of the abdominal muscles in other age groups compared to those in the 20s age group, and significant increases in echo intensity of the back muscles in the age groups over 40 compared to those in the 20s group. CONCLUSION: Our study revealed that muscle quality may be more affected by age than muscle quantity and the effects of aging differ among muscles.

Verification of reliability and validity of motion analysis systems during bilateral squat using human pose tracking algorithm.

BACKGROUND: The human tracking algorithm called OpenPose can detect joint points and calculate joint angles. However, the reliability and validity of OpenPose have not been clarified yet. RESEARCH QUESTION: Are there the enough reliability and validity of OpenPose based motion analysis? METHODS: 20 healthy young subjects participated in this study. The motion task was a bilateral squat. The joint angles of the trunk, hip, knee, and ankle were calculated using OpenPose and VICON. Kinematic measurements by three-dimensional motion analysis devices were recorded using VICON. Simultaneously, the images were taken with a digital camera from the right side. After the images were processed with OpenPose, joint angles were calculated from estimated joint points. To confirm the test-retest reliability within device, intraclass correlation coefficients [ICC (1, 3)] were calculated. To confirm the validity, linear regression analysis and ICC (2, 1) between the data obtained by OpenPose and VICON were calculated. Furthermore, the agreement between the data obtained by OpenPose and VICON was assessed by Bland-Altman analysis. RESULTS: ICCs (1, 3) of the data obtained by OpenPose and VICON were almost perfect. There were significant associations between the data obtained by OpenPose and VICON. ICCs (2, 1) between the data obtained by OpenPose and VICON were almost perfect or substantial for trunk, knee and ankle joints, and fair on the hip joint. There were fixed biases on knee and ankle joints, and proportional biases on trunk and hip joint. SIGNIFICANCE: OpenPose based motion analysis is reliable and has the advantage of being low cost and easier to operate than conventional methods. In future, to consider the clinical utility of OpenPose, it is necessary to identify the error between the true values indicating actual joint movement and data obtained by OpenPose with its correction for fixed and proportional biases. (295 words).

A new method to confirm the absence of human and animal serum in mesenchymal stem cell culture media.

Mesenchymal stem cells are an ideal source for regenerative medicine. For clinical use, cell culture should be done at stable conditions, thus the use of serum should be avoided because of the batch-to-batch variations of serum. Although several kinds of serum-free media are available, a method to confirm whether they contain serum has not been established yet. During studies on effect of adipocyte mesenchymal stem cells (Ad-MSCs) on pain using a human pain gene array, we noticed that BDKRB1 gene was constantly upregulated when serum was used in the culture medium. In this study, we attempted to establish further the potential of this gene as a new marker indicative of the presence of serum in media. Using a real-time quantitative PCR gene array screening containing 84 functional genes, we verified BDKRB1 as a specific gene upregulated in the presence of serum. The expression of BDKRB1 in Ad-MSCs was induced not only by bovine serum but also by human serum. The BDKRB1 expression was induced even when Ad-MSCs was cultured with 0.1% serum in the medium. We concluded that BDKRB1 is a valuable marker to detect traces of both human and animal serum in Ad-MSCs cultures. Our study provides a new method to confirm the absence of serum in media and ensure a stable cell culture condition.

Effect of the Aspect Ratio of Coiled-Coil Protein Carriers on Cellular Uptake.

We showed previously that a rigid and fibrous-structured cationic coiled-coil artificial protein had cell-penetrating activity that was significantly greater when compared with a less-structured cell-penetrating peptide. Nanomaterials with anisotropic structures often show aspect-ratio-dependent unique physicochemical properties, as well as cell-penetrating activities. In this report, we have designed and demonstrated the cell-penetrating activity of a shorter cationic coiled-coil protein. An aspect ratio at 4.5:1 was found to be critical for ensuring that the cationic coiled-coil protein showed strong cell-penetrating activity. At an aspect ratio of 3.5:1, the cationic coiled-coil protein showed cell-penetrating activity that was similar to a less-structured short cationic cell-penetrating peptide. Interestingly, at an aspect ratio of 4:1, the cationic coiled-coil protein exhibited intermediate cell-penetrating activity. These findings should aid in the principle design of intracellular drug delivery carriers including coiled-coil artificial proteins, their derivatives, and α-helical cell-penetrating peptides as well as provide a framework for developing synthetic nanomaterials, such as metal nanorods and synthetic polymers.

Adipose-Derived Mesenchymal Stem Cells Restore Impaired Mucosal Immune Responses in Aged Mice.

It has been shown that adipose-derived mesenchymal stem cells (AMSCs) can differentiate into adipocytes, chondrocytes and osteoblasts. Several clinical trials have shown the ability of AMSCs to regenerate these differentiated cell types. Age-associated dysregulation of the gastrointestinal (GI) immune system has been well documented. Our previous studies showed that impaired mucosal immunity in the GI tract occurs earlier during agingthan is seen in the systemic compartment. In this study, we examined the potential of AMSCs to restore the GI mucosal immune system in aged mice. Aged (>18 mo old) mice were adoptively transferred with AMSCs. Two weeks later, mice were orally immunized with ovalbumin (OVA) plus cholera toxin (CT) three times at weekly intervals. Seven days after the final immunization, when fecal extract samples and plasma were subjected to OVA- and CT-B-specific ELISA, elevated levels of mucosal secretory IgA (SIgA) and plasma IgG antibody (Ab) responses were noted in aged mouse recipients. Similar results were also seen aged mice which received AMSCs at one year of age. When cytokine production was examined, OVA-stimulated Peyer's patch CD4+ T cells produced increased levels of IL-4. Further, CD4+ T cells from the lamina propria revealed elevated levels of IL-4 and IFN-γ production. In contrast, aged mice without AMSC transfer showed essentially no OVA- or CT-B-specific mucosal SIgA or plasma IgG Ab or cytokine responses. Of importance, fecal extracts from AMSC transferred aged mice showed neutralization activity to CT intoxication. These results suggest that AMSCs can restore impaired mucosal immunity in the GI tract of aged mice.

A recombinant varicella vaccine harboring a respiratory syncytial virus gene induces humoral immunity.

The varicella-zoster virus (VZV) Oka vaccine strain (vOka) is highly efficient and causes few adverse events; therefore, it is used worldwide. We previously constructed recombinant vOka (rvOka) harboring the mumps virus gene. Immunizing guinea pigs with rvOka induced the production of neutralizing antibodies against the mumps virus and VZV. Here, we constructed recombinant vOka viruses containing either the respiratory syncytial virus (RSV) subgroup A fusion glycoprotein (RSV A-F) gene or RSV subgroup B fusion glycoprotein (RSV B-F) gene (rvOka-RSV A-F or rvOka-RSV B-F). Indirect immunofluorescence and Western blot analyses confirmed the expression of each recombinant RSV protein in virus-infected cells. Immunizing guinea pigs with rvOka-RSV A-F or rvOka-RSV B-F led to the induction of antibodies against RSV proteins. These results suggest that the current varicella vaccine genome can be used to generate custom-made vaccine vectors to develop the next generation of live vaccines.

MHC class I molecules are incorporated into human herpesvirus-6 viral particles and released into the extracellular environment.

Human herpesvirus-6 (HHV-6), which belongs to the betaherpesvirus subfamily, mainly replicates in T lymphocytes. Here, we show that MHC class I molecules are incorporated into HHV-6 viral particles and released into the extracellular environment. In addition, HHV-6A/B-infected T cells showed reduced surface and intracellular expression of MHC class I molecules. The cellular machinery responsible for molecular transport appears to be modified upon HHV-6 infection, causing MHC class I molecules to be transported to virion assembly sites.

Novel polyvalent live vaccine against varicella-zoster and mumps virus infections.

The varicella-zoster virus (VZV) Oka vaccine strain (vOka) is a highly immunogenic and safe live vaccine that has long been used worldwide. Because its genome is large, making it suitable for inserting foreign genes, vOka is considered a candidate vector for novel polyvalent vaccines. Previously, a recombinant vOka, rvOka-HN, that expresses mumps virus (MuV) hemagglutinin-neuraminidase (HN) was generated by the present team. rvOka-HN induces production of neutralizing antibodies against MuV in guinea pigs. MuV also expresses fusion (F) protein, which is important for inducing neutralizing antibodies, in its viral envelope. To induce a more robust immune response against MuV than that obtained with rvOka-HN, here an rvOka expressing both HN and F (rvOka-HN-F) was generated. However, co-expression of HN and F caused the infected cells to form syncytia, which reduced virus titers. To reduce the amount of cell fusion, an rvOka expressing HN and a mutant F, F(S195Y) were generated. Almost no syncytia formed among the rvOka-HN-F(S195Y)-infected cells and the growth of rvOka-HN-F(S195Y) was similar to that of the original vOka clone. Moreover, replacement of serine 195 with tyrosine had no effect on the immunogenicity of F in mice and guinea pigs. Although obvious augmentation of neutralizing antibody production was not observed after adding F protein to vOka-HN, the anti-F antibodies did have neutralizing activity. These data suggest that F protein contributes to induction of immune protection against MuV. Therefore this recombinant virus is a promising candidate vaccine for polyvalent protection against both VZV and MuV.

CD134 is a cellular receptor specific for human herpesvirus-6B entry.

Human herpesvirus-6B (HHV-6B) is a T lymphotropic ß-herpesvirus that is clearly distinct from human herpesvirus-6A (HHV-6A) according to molecular biological features. The International Committee on Taxonomy of Viruses recently classified HHV-6B as a separate species. The primary HHV-6B infection causes exanthem subitum and is sometimes associated with severe encephalopathy. More than 90% of the general population is infected with HHV-6B during childhood, and the virus remains throughout life as a latent infection. HHV-6B reactivation causes encephalitis in immunosuppressed patients. The cellular receptor for HHV-6A entry was identified as human CD46, but the receptor for HHV-6B has not been clear. Here we found that CD134, a member of the TNF receptor superfamily, functions as a specific entry receptor for HHV-6B. A T-cell line that is normally nonpermissive for HHV-6B infection became highly susceptible to infection when CD134 was overexpressed. CD134 was down-regulated in HHV-6B-infected T cells. Soluble CD134 interacted with the HHV-6B glycoprotein complex that serves as a viral ligand for cellular receptor, which inhibited HHV-6B but not HHV-6A infection in target cells. The identification of CD134 as an HHV-6B specific entry receptor provides important insight into understanding HHV-6B entry and its pathogenesis.

Complementation of the function of glycoprotein H of human herpesvirus 6 variant A by glycoprotein H of variant B in the virus life cycle.

Human herpesvirus 6 (HHV-6) is a T-cell-tropic betaherpesvirus. HHV-6 can be classified into two variants, HHV-6 variant A (HHV-6A) and HHV-6B, based on genetic, antigenic, and cell tropisms, although the homology of their entire genomic sequences is nearly 90%. The HHV-6A glycoprotein complex gH/gL/gQ1/gQ2 is a viral ligand that binds to the cellular receptor human CD46. Because gH has 94.3% amino acid identity between the variants, here we examined whether gH from one variant could complement its loss in the other. Recently, we successfully reconstituted HHV-6A from its cloned genome in a bacterial artificial chromosome (BAC) (rHHV-6ABAC). Using this system, we constructed HHV-6ABAC DNA containing the HHV-6B gH (BgH) gene instead of the HHV-6A gH (AgH) gene in Escherichia coli. Recombinant HHV-6ABAC expressing BgH (rHHV-6ABAC-BgH) was successfully reconstituted. In addition, a monoclonal antibody that blocks HHV-6B but not HHV-6A infection neutralized rHHV-6ABAC-BgH but not rHHV-6ABAC. These results indicate that HHV-6B gH can complement the function of HHV-6A gH in the viral infectious cycle.

Age-related changes in the thickness of the deep and superficial abdominal muscles in women.

The study investigated age-related changes in the thickness of the deep and superficial abdominal muscles of 103 healthy women who could walk independently The participants were classified into five age groups: young (n=26; 20-24 years), young adult (n=26; 25-44 years), middle-aged (n=16; 45-64 years), young-old (n=16; 65-74 years), and old-old (n=19; 75-85 years). The muscle thicknesses of the right rectus abdominis, external oblique, internal oblique, and transversus abdominis were measured using ultrasound imaging. The rectus abdominis was significantly thicker in the young group compared with the young adult, middle-aged, young-old, and old-old groups (p<0.05). The external oblique and internal oblique muscles were significantly thicker in the young group compared with the middle-aged, young-old, and old-old groups (p<0.05). However, there were no significant differences in the thickness of the transversus abdominis between groups. The results suggest that age-related muscle atrophy occurs from an early age in superficial abdominal muscles, such as rectus abdominis, and that age-related atrophy is less in deep abdominal muscles such as the transversus abdominis.

Characterization of varicella-zoster virus-encoded ORF0 gene--comparison of parental and vaccine strains.

The varicella-zoster virus (VZV) Oka vaccine strain (vOka) differs from the parental strain (pOka) at several amino acid positions, but the mutations responsible for the attenuation of vOka have not been clearly defined. The ORF0 of vOka carries some of the mutations. Although we found that the ORF0 of both strains was incorporated into virus particles, the C-terminal region of vOka ORF0 was presented on the virion surface and was N-glycosylated, suggesting that the mutation in vOka ORF0 changes it into a novel envelope glycoprotein. In a mutant virus in which pOka ORF0 was replaced by vOka ORF0, the molecular weight of ORF0 was altered, but the plaque size was not. In addition, a pOka recombinant virus lacking the hydrophobic domain of ORF0 grew equally well as the wild-type virus, indicating that the mutation in ORF0 is not by itself sufficient for the attenuation of the vOka virus.