Association between trunk extensor strength and gait-induced back pain in the elderly with adult spinal deformity: a cross-sectional study.

PURPOSE: The purpose of the present study was to investigate the association between quantitatively assessed trunk extensor strength and gait-induced back pain (GIBP) in patients with adult spinal deformity (ASD). METHODS: Ninety-five patients with ASD aged ≥ 50 years who were admitted to our hospital between April 2018 and March 2023 were included in the study. GIBP was evaluated through a 6-minute walking test (6MWT), with GIBP being defined as the occurrence of back pain during the evaluation and inability to complete the test. The patients were divided into three groups: difficulty completing the 6MWT (Group 1), ability to complete the 6MWT with breaks (Group 2), and ability to complete the 6MWT without taking a break (Group 3). The main independent variable was trunk extensor strength, which was measured using a hand-held dynamometer. Ordered logistic regression analysis was conducted to assess the association between GIBP and trunk extensor strength while adjusting for basic characteristics and radiographic parameters as covariates. RESULTS: The numbers of patients with ASD included in each group were; 27 in Group 1 (28.4%), 31 in Group 2 (32.6%), and 37 in Group 3 (39.0%). An ordered logistic regression analysis adjusted for basic characteristics and radiographic parameters, trunk extensor strength was significantly associated with GIBP (odds ratios, 1.128; 95% confidence intervals, 1.025-1.242). CONCLUSIONS: The results of the present study strongly indicate that trunk extensor strength is a valuable factor associated with GIBP in patients with ASD.

Proteomic profiling of FFPE specimens: Discovery of HNRNPA2/B1 and STT3B as biomarkers for determining formalin fixation durations.

Recent advancements in proteomics technologies using formalin-fixed paraffin-embedded (FFPE) samples have significantly advanced biomarker discovery. Yet, the effects of varying sample preparation protocols on proteomic analyses remain poorly understood. We analyzed mouse liver FFPE samples that varied in fixatives, fixation duration, and storage temperature using LC/MS. We found that variations in fixation duration significantly affected the abundance of specific proteins, showing that HNRNPA2/B1 demonstrated a significant decrease in abundance in samples fixed for long periods, whereas STT3B exhibited a significant increase in abundance in samples fixed for long durations. These findings were supported by immunohistochemical analysis across liver, spleen, and lung tissues, demonstrating a significant decrease in the nuclear staining of HNRNPA2/B1 in long-duration acid formalin(AF)-fixed FFPE samples, and an increase in cytoplasmic staining of STT3B in long-duration neutral buffered formalin-fixed liver and lung tissues and granular staining in all long-duration AF-fixed FFPE tissue types. Similar trends were observed in the long-duration fixed HeLa cells. These results demonstrate that fixation duration critically affects the proteomic integrity of FFPE samples, emphasizing the urgent need for standardized fixation protocols to ensure consistent and reliable proteomic data. SIGNIFICANCE: The quality of FFPE samples is primarily influenced by the fixation and storage conditions. However, previous studies have mainly focused on their impact on nucleic acids and the extent to which different fixation conditions affect changes in proteins has not been evaluated. In addition, to our knowledge, proteomic research focusing on differences in formalin fixation conditions has not yet been conducted. Here, we analyzed FFPE samples with different formalin fixation and storage conditions using LC/MS and evaluated the impact of different fixation conditions on protein variations. Our study unequivocally established formalin fixation duration as a critical determinant of protein variation in FFPE specimens and successfully identified HNRNPA2/B1 and STT3B as potential biomarkers for predicting formalin fixation duration for the first time. The study findings open new avenues for quality assessment in biomedical research and diagnostics.

Formalin-Fixed Paraffin-Embedded Proteomics of Malignant Mesothelioma and New Candidate Biomarkers Thioredoxin and Superoxide Dismutase 2 for Immunohistochemistry.

The pathogenesis of malignant mesothelioma (MM) has been extensively investigated, focusing on stress derived from reactive oxygen species. We aimed to identify diagnostic biomarkers of MM by analyzing proteins in formalin-fixed paraffin-embedded specimens using liquid chromatography-mass spectrometry. We extracted proteins from formalin-fixed paraffin-embedded sections of MM tissues (n = 7) and compared their profiles with those of benign mesothelial tissues (n = 4) and alveolar tissue (n = 1). Proteomic data were statistically assessed and profiled using principal component analysis. We were successful in the classification of MM and healthy tissue. The levels of superoxide dismutase 2 (SOD2), an enzyme that converts superoxide anion into oxygen and hydrogen peroxide, and thioredoxin (TXN), which plays a crucial role in reducing disulfide bonds in proteins, primarily contributed to the classification. Other redox-related proteins, such as pyruvate dehydrogenase subunit X, and ceruloplasmin also contributed to the classification. Protein-protein interaction analysis demonstrated that these proteins play essential roles in MM pathogenesis. Immunohistochemistry revealed that TXN levels were significantly lower, whereas SOD2 levels were significantly higher in MM and lung cancer tissues than in controls. Proteomic profiling suggested that MM tissues experienced increased exposure to hydrogen peroxide and other reactive oxygen species. Combining immunohistochemistry for TXN and SOD2 allows for differentiation among MM, lung cancer, and control tissues; hence, TXN and SOD2 may be promising MM biomarkers and therapeutic targets.

Influence of changes in pelvic anteversion during gait on walking ability and physical function in patients with adult spinal deformity: A cross-sectional study.

BACKGROUNDS: Evaluation of gait posture using a three-dimensional motion analysis system (3DMAS) revealed that elderly patients with adult spinal deformity (ASD) experience pelvic anteversion while walking. The purpose of this study was to investigate the influence of changes in pelvic anteversion during gait on walking ability and physical function in patients with ASD. METHODS: Fifty-four patients with ASD aged 50 years or older who were admitted to our hospital between March 2016 and December 2021 were included in the study. The 6-min walking distance (6MWD) was used to evaluate walking ability, and trunk and hip extensor strength were measured to evaluate physical function in the subjects. The 3DMAS was used to measure the subject's changes in pelvic anteversion during gait. After measuring the changes in pelvic anteversion, the median value of the study subjects was calculated, according to which the subjects were divided into two groups (small anteversion [S] group, large anteversion [L] group). Walking ability and physical function were compared between the two groups. RESULTS: The number of subjects in each group was 27. Comparisons of walking ability and physical function between the groups revealed significant differences in 6MWD (S group, 333.6 ± 111.2 m; L group, 238.0 ± 106.3 m) and hip extensor strength (S group, 15.8 ± 3.8 kgf; L group, 13.4 ± 4.4 kgf). No significant differences regarding trunk extensor strength were observed between the groups (S group, 15.2 ± 4.0 kgf; L group, 12.9 ± 4.8 kgf). CONCLUSION: The results of the present study revealed that ASD patients with greater pelvic anteversion associated with walking have lower walking ability and physical function. These results suggest the importance of evaluating the posture of ASD patients not only by using radiographic findings but also by assessing movement, such as gait posture.

Proteome analysis of CD5-positive diffuse large B cell lymphoma FFPE tissue reveals downregulation of DDX3X, DNAJB1, and B cell receptor signaling pathway proteins including BTK and Immunoglobulins.

BACKGROUND: The molecular pathology of diffuse large B cell lymphoma (DLBCL) has been extensively studied. Among DLBCL subtypes, the prognosis of CD5-positive DLBCL is worse than that of CD5-negative DLBCL, considering the central nervous system relapse and poor response to R-CHOP therapy. However, the molecular mechanisms underlying the tumorigenesis and progression of CD5-positive DLBCL remain unknown. METHODS: To identify molecular markers that can be targeted for treating DLBCL, a proteomic study was performed using liquid chromatography-mass spectrometry with chemically pretreated formalin-fixed paraffin-embedded specimens from CD5-positive (n = 5) and CD5-negative DLBCL patients (n = 6). RESULTS: Twenty-one proteins showed significant downregulation in CD5-positive DLBCL compared to CD5-negative DLBCL. Principal component analysis of protein expression profiling in CD5-positive and CD5-negative DLBCL revealed that DNAJB1, DDX3X, and BTK, which is one of the B cell phenotypic proteins, were the most significantly downregulated proteins and served as biomarkers that distinguished both groups. Additionally, a set of immunoglobulins, including IgG4, exhibited significant downregulation. Immunohistochemistry analysis for BTK demonstrated reduced staining in CD5-positive DLBCL compared to CD5-negative DLBCL. CONCLUSIONS: In conclusion, DNAJB1 and DDX3X, BTK, and a set of immunoglobulins are promising biomarkers. Probably, the suppression of BCR signaling is the unique phenotype of CD5-positive DLBCL. This formalin-fixed paraffin-embedded (FFPE)-based profiling may help to develop novel therapeutic molecularly targeted drugs for treating DLBCL.

Is dynamic spino-pelvic alignment during gait associated with lumbar function in patients with degenerative lumbar spinal stenosis?

INTRODUCTION: Static spine and pelvic posture has been reported to be associated with symptoms in patients with lumbar spinal stenosis (LSS), but it is unknown whether dynamic alignment of the spine and pelvis is associated with lumbar function in daily life. This study aims to investigate the relationship between dynamic alignment of the spine and pelvis during gait and lumbar function in daily life in patients with LSS. METHODS: We evaluated lumbar function in daily life using the Oswestry Disability Index (ODI), trunk and hip muscle strength as physical function, static spinal alignment, and dynamic spinal/pelvic alignment during gait. The relationship between the ODI score and physical function or static and dynamic alignment was examined. RESULTS: A total of 35 preoperative patients with LSS participated in this study. ODI score significantly correlated with trunk extension strength (r = -0.578, p = 0.000), hip extension strength (r = -0.472, p = 0.004), maximum spinal flexion angle during gait (r = -0.473, p = 0.004) and maximum pelvic anterior tilt angle (r = 0.510, p = 0.002). Multiple regression analysis showed that trunk extension strength (standardized ß; - 0.309), hip extension strength (standardized ß; -0.287), maximum spinal flexion angle (standardized ß; - 0.306) and maximum pelvic anterior tilt angle (standardized ß; 0.271) significantly affected the ODI score, with adjusted coefficient of determination of 0.529. CONCLUSION: The results of this study showed that the patients with LSS with weak hip or trunk extensor muscles, a greater angle of pelvic tilt or a less spinal flexion during gait had a lower lumbar function in daily life.

Novel assessment of physiotherapy outcomes in adults with structural spinal disorders.

PURPOSE: The aim is to investigate whether a simple prone posture assessment test (P-test) at baseline can be predict the effectiveness of at least 3 months of physiotherapy for adults with structural spinal disorders. METHODS: Seventy-six adults (age 71.0 ± 7.1 years) with structural spinal disorders who visited our outpatient clinic and underwent physiotherapy, which included muscle strength and range of motion training was provided once a week for a minimum of 3 months, and where the load was adjusted individually by the physiotherapist. The P-test is performed with the subject lying on the bed in a prone position and is positive if no low back pain is seen and the abdomen touches the bed. The Oswestry Disability Index (ODI) was used to assess disability. The minimum clinically important difference (MCID) was set at 10% improvement of the ODI score. Logistic regression analysis was performed to investigate the association between baseline P-test and achievement of ODI-MCID. RESULTS: The study population characteristics were: Sagittal vertical axis 138.1 ± 73.2 mm; Pelvic tilt, 36.9 ± 9.8 degrees; Pelvic incidence minus lumbar lordosis, 45.3 ± 22.1 degrees; and maximum coronal Cobb angle, 21.3 ± 19.7 degrees. Logistic regression analysis showed that being positive on the P-test was associated with the achievement of ODI-MCID (Odds ratio, 8.381; 95% confidence interval, 2.487-35.257). CONCLUSIONS: This study found that our developed P-test was a useful predictor of achieving the ODI-MCID in a cohort of adults with structural spinal disorders receiving at least 3 months of physiotherapy.

Cumulated ambulation score in hospitalized patients with osteoporotic vertebral fractures is an important predictor of returning home: a retrospective cohort study.

Osteoporotic vertebral fractures are recognized as a serious problem in the aging society. In this study, we found that the cumulated ambulation score predicts returning home in patients with osteoporotic vertebral fractures. The cumulated ambulation score is an important piece of information in determining the destination of patients with osteoporotic vertebral fractures. PURPOSE: Osteoporotic vertebral fractures are a serious problem affecting the health status of the elderly, and if they require inpatient treatment, they may have difficulty deciding where to discharge. The study's purpose is to investigate whether the cumulated ambulation scores predict returning home for hospitalized osteoporotic vertebral fractures patients. METHODS: The subjects were 120 osteoporotic vertebral fractures patients aged 65 years or older who were admitted to our hospital between April 2015 and March 2022. The cumulated ambulation scores for all subjects were measured in the 3-days right after admission. A multivariable analysis was performed with the dependent variable as whether the patient returned home and the independent variable as the cumulated ambulation score. Three models were created from the measured cumulated ambulation score, and each model was analyzed as an independent variable (model 1; score on the 1st day, model 2; total score on the 2-days, model 3; total score on the 3-days). RESULTS: The length of hospitalization for the osteoporotic vertebral fracture's patients were 11.8 ± 5.3 days, and 80 (66.7%) returned home. Multivariable analysis showed that cumulated ambulation score was a predictor of returning home (model 1, odds ratio: 3.151, 95% confidence interval: 2.074-5.203; model 2, odds ratio: 2.234, 95% confidence interval: 1.685-3.187; model 3, odds ratio: 1.929, 95% confidence interval: 1.535-2.599). CONCLUSION: The cumulated ambulation score of patients with osteoporotic vertebral fractures right after admission is a factor that affected returning home and is useful in determining where patients are discharged.

The association of dynamic spinal alignment on gait endurance of patients with adult spinal deformity: a cross-sectional study.

PURPOSE: The purpose of this study was to evaluate the gait posture of patients with adult spinal deformity (ASD) using a 3-dimensional motion analysis system (3DMAS) and to investigate whether it affects gait endurance. METHODS: Fifty-one patients with ASD aged 50 years or older who were admitted to our hospital between March 2016 and March 2018 were included in the study. The subjects completed the 6-min walking test, which is an indicator of gait endurance. Static standing posture was assessed by whole-spine x-ray examination (coronal cobb angle, CCA; sagittal vertical axis, SVA; pelvic tilt, PT; and pelvic incidence minus lumbar lordosis, PI-LL). In addition, the gait posture was evaluated by a 3DMAS (dynamic trunk tilt angle, DTA; and dynamic pelvic tilt angle, DPA). The relationship between standing and gait postures and gait endurance was investigated by multivariable analysis. RESULTS: In univariable analysis, SVA, PI-LL, and DTA were associated with gait endurance. Furthermore, in the multivariable analysis, DTA showed the strongest association among the static and dynamic parameters (R2 = 0.61, ß = - 0.35, P < 0.05). CONCLUSIONS: An association was found between gait posture and gait endurance in patients with ASD. These findings can be useful to health care providers treating patients with ASD. It is advisable to assess the gait posture of patients with ASD because they present postural abnormalities during gait.

Relationship between Lower Limb Pain Intensity and Dynamic Lumbopelvic-Hip Alignment in Patients with Degenerative Lumbar Spinal Canal Stenosis: A Cross-Sectional Study.

STUDY DESIGN: This cross-sectional study was conducted in a single hospital. PURPOSE: To clarify the relationship between lower limb pain intensity and dynamic lumbopelvic-hip alignment in patients with lumbar spinal canal stenosis (LSS), using a three-dimensional (3D) motion analysis system. OVERVIEW OF LITERATURE: Although it is well known that leg symptoms have a close relationship with posture in patients with LSS, the relationship under dynamic conditions, such as gait, remain unclear. METHODS: Thirty patients with LSS scheduled for spine surgery participated in this study. Lower limb pain was assessed using the Visual Analog Scale (VAS), and the patients were divided into two groups based on the mean scores (patients with scores above and below the mean were classified as the high-VAS and low-VAS groups, respectively). The kinematics of the spine, pelvis, and hip joints during gait were then measured using a 3D motion analysis system. Student paired t -tests were used to compare the angles of the spine, pelvis, and hip during gait between the two groups. RESULTS: Compared to those in the low-VAS group, the spine was significantly extended and bent toward the more painful lower limb side, and the pelvis was significantly anteriorly tilted among individuals in the high-VAS group. CONCLUSIONS: Patients with LSS experiencing severe pain in their lower limb tend to keep the spine in a more extended position, bend laterally toward the painful side, and have an anteriorly tilted pelvic posture. The dynamic spinal and pelvic alignment was closely related to the intensity of the lower limb pain.

Maximum gait speed and lumbar spinal mobility can affect quality of life in elderly women with lumbar kyphosis.

Background: The site and angle of kyphosis are important factors that affect quality of life (QOL). Lumbar kyphosis, rather than thoracic kyphosis, is reported to affect the QOL in patients with kyphosis. Increased angle of kyphosis in elderly people is associated with a decline in motor and physical functions, and also correlates with reduced QOL. Investigation of how physical performance affects their QOL would be helpful in developing an effective physical therapy program for elderly patients with kyphosis. The aims of the current study were to evaluate the physical performance including back muscle strength, spinal range of motion, and walking ability in elderly patients with lumbar kyphosis, and to examine its association with back pain-specific QOL. Methods: The design of this study is a cross-sectional study in a single hospital. A total of 51 elderly women aged 65 years or older diagnosed with kyphosis were enrolled in the study. The items evaluated were back pain (visual analog scale [VAS]), back-pain specific QOL (the Oswestry Disability Index [ODI]), maximum gait speed, thoracic kyphosis angle, lumbar lordosis angle, sacral inclination, spinal inclination, trunk extension/flexion range of motion (ROM), thoracic spinal ROM, lumbar spinal ROM, and back muscle strength. Data were analyzed using bivariate analyses and multivariate regression analyses. Results: Significant positive correlations were observed between ODI and VAS (rs=0.506) or spinal inclination (rs=0.626). Significant negative correlations were observed between ODI and maximum gait speed (rs=-0.664), lumbar lordosis angle, (rs=-0.553), trunk extension ROM (rs=-0.571), lumbar spinal ROM (rs=-0.651), or back muscle strength (rs=-0.521). Multiple regression analysis demonstrated that maximum gait speed (standard partial regression coefficient; b=0.484) and lumbar spinal ROM (b=0.463) had a significant impact on ODI. The results of analysis of variance were significant with R2 of 0.622. Conclusions: The current study demonstrated that maximum gait speed and lumbar spinal ROM influenced back-pain specific QOL in the elderly women with lumbar kyphosis. Maximum gait speed and lumbar spinal ROM should be evaluated thoroughly to effectively perform non-operative treatment in elderly people with lumbar kyphosis.

Hip Extensor Strength Influences Dynamic Postural Changes during Gait in Patients with Adult Spinal Deformity: A Cross-Sectional Study Using Three-Dimensional Motion Analysis.

STUDY DESIGN: Single-hospital cross-sectional study. PURPOSE: The aim of the present study was to investigate the physical functions influencing dynamic postural change in patients with adult spinal deformity (ASD). OVERVIEW OF LITERATURE: Dynamic postural change leading to increased forward lean during gait is a problem in patients with ASD; however, the relationship between this change and trunk and hip extensor strength is unclear. METHODS: Thirty patients with ASD aged ≥50 years who were admitted to our hospital between July 2016 and September 2019 were included in this study. X-ray parameters (i.e., sagittal vertical axis, pelvic tilt, and pelvic incidence minus lumbar lordosis) were evaluated from the full-length standing radiographs of the subjects. Trunk and hip extensor strength was evaluated using a hand-held dynamometer. Dynamic postural changes (i.e., sagittal trunk shift during standing, sagittal trunk shift during gait, and delta sagittal trunk shift) were assessed using a three-dimensional motion analysis system. The relationships between dynamic postural change and various X-ray parameters, as well as trunk and hip extensor strength, were examined using multivariable analysis. RESULTS: Multivariable analysis showed that hip extensor strength is the factor most strongly associated with dynamic postural change among the X-ray parameters and physical functions assessed in this study (ß=-0.41, R2=0.12). CONCLUSIONS: We demonstrated the association between dynamic postural change and hip extensor strength in patients with ASD. Our results may be useful to healthcare providers treating patients with ASD. Interventions for dynamic postural change in patients with ASD should focus on hip extensor strength.

Reciprocal relationship between locomotive syndrome and social frailty in older adults.

AIM: States of vulnerability are multidimensional and become more prevalent with advancing age. These states and the causal relationships between them, merit thorough investigation. This study aimed to understand the reciprocal relationship between the constructs of the locomotive syndrome and social frailty among a community of older adults. METHODS: This 2-year cohort study examined a community of older adults (≥75 years) consisting of 1177 members. Using Makizako's method, social frailty was deemed to be present if more than two out of five questions were answered negatively. Locomotive syndrome was measured with the Geriatric Locomotive Function Scale-25, which consists of 25 items measuring an individual's risk of developing locomotive syndrome; a total score of ≥16 identified the presence of locomotive syndrome. Possible reciprocal associations between locomotive syndrome and social frailty were assessed using Cox proportional hazards analyses. RESULTS: A total of 748 older adults were analyzed in the following subgroups. Among 574 participants without social frailty at the baseline, the presence of locomotive syndrome at the baseline was associated with new-onset social frailty during the next 2 years, after adjusting for confounding factors (hazard ratio 1.76, 95% confidence interval 1.17-2.65). Conversely, the presence of social frailty among participants without locomotive syndrome in the baseline was not associated with new-onset locomotive syndrome. CONCLUSION: The presence of locomotive syndrome was determined to be a risk factor for the onset of social frailty. Therefore, interventions that address the negative impact of locomotive syndrome are a first step toward addressing these vulnerable conditions. Geriatr Gerontol Int 2021; 21: 981-984.

Clinical outcomes of lumbar diseases specific test in patients who undergo endoscopy-assisted tubular surgery with lumbar herniated nucleus pulposus: an analysis using the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ).

PURPOSE: This study was to evaluate clinical outcomes using a patient-oriented test that scores health-related quality of life (HRQOL) for patients after minimally invasive surgery using microendoscopic discectomy (MED) for lumbar disc hernia. Few studies regarding MED in terms of disease-specific quality of life measures using Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) have been published. METHODS: Retrospective analysis of the surgical and clinical outcomes with regard to reducing pain and improving the functional status for 31 patients who underwent MED for lumbar disc hernia was conducted. These patients were evaluated at 3-year follow-up. The evaluations were based on a visual analogue scale (VAS), the Japanese Orthopaedic Association (JOA) scoring system, and the JOABPEQ, which is an objective, patient-oriented test that assesses HRQOL in patients with lumbar disorders. RESULTS: A low rate of improvement was seen only in mental health until 1 year, the low rate of improvement in mental health and was independently correlated with body mass index (BMI), pre-operative scores on the Brief Scale for Psychiatric problems in Orthopaedic Patients (BS-POP), and scores on the BS-POP at 12 months post-operatively. CONCLUSIONS: All categories of VAS, JOA scores, and all domains of JOABPEQ were significantly higher over 3 years than those obtained pre-operatively. But only mental health domain showed mild improvement until 1 year. Moreover, BMI showed a negative correlation with improvements in the mental health domain post-operatively. As patients may be mentally exhausted from lumbar disc herniation, pre-operative mental health may be improved by surgical treatment.

Coexistence of Chronic Musculoskeletal Pain and Depressive Symptoms and Their Combined and Individual Effects on Onset of Disability in Older Adults: A Cohort Study.

OBJECTIVES: Coexistence of chronic musculoskeletal pain and depressive symptoms is common, and their combined effect on adverse events warrants investigation. The purpose of this study was to investigate the individual and combined effect of chronic musculoskeletal pain and depressive symptoms on the onset of disability, which is a crucial outcome in older adults. DESIGN: A 1-year cohort study. SETTING AND PARTICIPANTS: 1251 community-dwelling older adults. MEASUREMENTS: The number of chronic musculoskeletal pain sites was measured using a self-reported questionnaire. Depressive symptoms were assessed using the Geriatric Depression Scale-15. Disability was self-reported as any difficulty in basic activities of daily living. Incidence of disability was defined as any difficulty in performing 1 or more tasks at the follow-up assessment, that was absent at baseline. RESULTS: Older adults with more chronic musculoskeletal pain sites tend to have depressive symptoms at baseline (P for trend < .001). Compared to older adults without both chronic musculoskeletal pain and depressive symptoms, older adults with both chronic multisite musculoskeletal pain and depressive symptoms have the higher risk for development of disability (adjusted odds ratio: 6.84, 95% confidence interval: 3.72 to 12.58), followed by older adults with chronic multisite musculoskeletal pain and without depressive symptoms (adjusted odds ratio: 2.13, 95% confidence interval: 1.35 to 3.37). CONCLUSIONS/IMPLICATIONS: Simultaneous assessment of both chronic musculoskeletal pain and depressive symptoms may be useful for accurate prognosis and preventing disability in older adults.

pH-Induced Association and Dissociation of Intermolecular Complexes Formed by Hydrogen Bonding between Diblock Copolymers.

Poly(sodium styrenesulfonate)⁻block⁻poly(acrylic acid) (PNaSS⁻b⁻PAA) and poly(sodium styrenesulfonate)⁻block⁻poly(N-isopropylacrylamide) (PNaSS⁻b⁻PNIPAM) were prepared via reversible addition⁻fragmentation chain transfer (RAFT) radical polymerization using a PNaSS-based macro-chain transfer agent. The molecular weight distributions (Mw/Mn) of PNaSS⁻b⁻PAA and PNaSS⁻b⁻PNIPAM were 1.18 and 1.39, respectively, suggesting that these polymers have controlled structures. When aqueous solutions of PNaSS⁻b⁻PAA and PNaSS⁻b⁻PNIPAM were mixed under acidic conditions, water-soluble PNaSS⁻b⁻PAA/PNaSS⁻b⁻PNIPAM complexes were formed as a result of hydrogen bonding interactions between the pendant carboxylic acids in the PAA block and the pendant amide groups in the PNIPAM block. The complex was characterized by ¹H NMR, dynamic light scattering, static light scattering, and transmission electron microscope measurements. The light scattering intensity of the complex depended on the mixing ratio of PNaSS⁻b⁻PAA and PNaSS⁻b⁻PNIPAM. When the molar ratio of the N-isopropylacrylamide (NIPAM) and acrylic acid (AA) units was near unity, the light scattering intensity reached a maximum, indicating stoichiometric complex formation. The complex dissociated at a pH higher than 4.0 because the hydrogen bonding interactions disappeared due to deprotonation of the pendant carboxylic acids in the PAA block.

The E3 ubiquitin ligase Hace1 is required for early embryonic development in Xenopus laevis.

BACKGROUND: HECT domain and ankyrin repeat containing E3 ubiquitin protein ligase 1 (HACE1) regulates a wide variety of cellular processes. It has been shown that one of the targets of HACE1 is the GTP-bound form of the small GTPase Rac1. However, the role of HACE1 in early development remains unknown. RESULTS: In situ hybridization revealed that Xenopus laevis hace1 is specifically expressed in the ectoderm at the blastula and gastrula stages and in the epidermis, branchial arch, kidney, and central nervous system at the tailbud stage. Knockdown of hace1 in Xenopus laevis embryos via antisense morpholino oligonucleotides led to defects in body axis elongation, pigment formation, and eye formation at the tadpole stage. Experiments with Keller sandwich explants showed that hace1 knockdown inhibited convergent extension, a morphogenetic movement known to be crucial for body axis elongation. In addition, time lapse imaging of whole embryos during the neurula stage indicated that hace1 knockdown also delayed neural tube closure. The defects caused by hace1 knockdown were partly rescued by knockdown of rac1. Moreover, embryos expressing a constitutively active form of Rac1 displayed phenotypes similar to those of embryos with hace1 knocked down. CONCLUSIONS: Our results suggest that Xenopus laevis hace1 plays an important role in early embryonic development, possibly via regulation of Rac1 activity.

The kinase SGK1 in the endoderm and mesoderm promotes ectodermal survival by down-regulating components of the death-inducing signaling complex.

A balance between cell survival and apoptosis is essential for animal development. Although proper development involves multiple interactions between germ layers, little is known about the intercellular and intertissue signaling pathways that promote cell survival in neighboring or distant germ layers. We found that serum- and glucocorticoid-inducible kinase 1 (SGK1) promoted ectodermal cell survival during early Xenopus embryogenesis through a non-cell-autonomous mechanism. Dorsal depletion of SGK1 in Xenopus embryos resulted in shortened axes and reduced head structures with defective eyes, and ventral depletion led to defective tail morphologies. Although the gene encoding SGK1 was mainly expressed in the endoderm and dorsal mesoderm, knockdown of SGK1 caused excessive apoptosis in the ectoderm. SGK1-depleted ectodermal explants showed little or no apoptosis, suggesting non-cell-autonomous effects of SGK1 on ectodermal cells. Microarray analysis revealed that SGK1 knockdown increased the expression of genes encoding FADD (Fas-associated death domain protein) and caspase-10, components of the death-inducing signaling complex (DISC). Inhibition of DISC function suppressed excessive apoptosis in SGK1-knockdown embryos. SGK1 acted through the transcription factor nuclear factor κB (NF-κB) to stimulate production of bone morphogenetic protein 7 (BMP7), and overexpression of BMP7 in SGK1-knockdown embryos reduced the abundance of DISC components. We show that phosphoinositide 3-kinase (PI3K) functioned upstream of SGK1, thus revealing an endodermal and mesodermal pathway from PI3K to SGK1 to NF-κB that produces BMP7, which promotes ectodermal survival by decreasing DISC function.

Preparation and characterization of a pH-responsive nanogel based on a photo-cross-linked micelle formed from block copolymers with controlled structure.

Poly(ethylene glycol)-b-poly(2-(diethylamino)ethyl methacrylate-co-2-cinnamoyloxyethyl acrylate) (PEG-b-P(DEAEMA/CEA)) was prepared by reversible addition-fragmentation chain transfer (RAFT)-controlled radical polymerization. As solution pH is increased from an acidic pH, the hydrodynamic radius (R(h)) increases abruptly near pH 7, indicative of the micelle formation at pH > 7. The micelle formation at pH > 7 was supported by (1)H NMR and light scattering data. Upon irradiation of light, polymer chains in the core of the polymer micelle are cross-linked as a result of the photodimerization of the cinnamoyl groups, yielding a nanogel. The nanogel was characterized by gel-permeation chromatography (GPC), light scattering, small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM), and fluorescence techniques. The nanogel displayed an ability to solubilize N-phenyl-1-naphthylamine (PNA) and 1-pyrenemethanol (hydrophobic guest molecules) into the hydrophobic core at pH > 7. It was confirmed with PNA that the solubilization of a guest molecule occurred at polymer concentrations (C(p)) lower than the critical micelle concentration (cmc) for PEG-b-P(DEAEMA/CEA) because the nanogel retains its micellar structure at C(p) < cmc. 1-Pyrenemethanol is strongly captured by the nanogel at pH 10, whereas it is easily released from the nanogel when pH is reduced to 3. This indicates that the hydrophobicity of the core of the nanogel can be modulated by a change in the degree of protonation of the DEAEMA units in the core, and thus the capture of a guest molecule and its release can be controlled by a change in solution pH.

Maize C4-form phosphoenolpyruvate carboxylase engineered to be functional in C3 plants: mutations for diminished sensitivity to feedback inhibitors and for increased substrate affinity.

Introducing a C(4)-like pathway into C(3) plants is one of the proposed strategies for the enhancement of photosynthetic productivity. For this purpose it is necessary to provide each component enzyme that exerts strong activity in the targeted C(3) plants. Here, a maize C(4)-form phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) was engineered for its regulatory and catalytic properties so as to be functional in the cells of C(3) plants. Firstly, amino acid residues Lys-835 and Arg-894 of maize PEPC, which correspond to Lys-773 and Arg-832 of Escherichia coli PEPC, respectively, were replaced by Gly, since they had been shown to be involved in the binding of allosteric inhibitors, malate or aspartate, by our X-ray crystallographic analysis of E. coli PEPC. The resulting mutant enzymes were active but their sensitivities to the inhibitors were greatly diminished. Secondly, a Ser residue (S780) characteristically conserved in all C(4)-form PEPC was replaced by Ala conserved in C(3)- and root-form PEPCs to decrease the half-maximal concentration (S(0.5)) of PEP. The double mutant enzyme (S780A/K835G) showed diminished sensitivity to malate and decreased S(0.5)(PEP) with equal maximal catalytic activity (V(m)) to the wild-type PEPC, which will be quite useful as a component of the C(4)-like pathway to be introduced into C(3) plants.