Risk factors for contralateral total knee arthroplasty after unilateral total knee arthroplasty.

BACKGROUND: Little attention has been focused on risk factors for undergoing bilateral total knee arthroplasty (TKA) after primary unilateral TKA among patients with knee osteoarthritis (OA). This study investigated the differences in characteristics between groups with and without additional TKA for the contralateral knee among patients with knee OA who underwent primary unilateral TKA. METHODS: Seventy-six patients who underwent primary unilateral TKA were included in this study. We defined patients who underwent additional TKA for the contralateral knee within one year of the primary TKA as a bilateral TKA group, and patients who did not undergo bilateral TKA as a unilateral TKA group. Femorotibial angle (FTA), percentage of mechanical axis (%MA), Kellgren-Lawrence (KL) grade, range of motion, Japan Orthopaedic Association (JOA) score, 10 m-walking time, C-reactive protein, estimated glomerular filtration rate, and serum albumin levels were selected as independent variables including covariates of age, sex, and body mass index for predicting bilateral TKA. We compared differences in variables between the two groups using the t-test or Mann-Whitney U-test and general linear models. A multivariate stepwise logistic regression model was also used to determine which variables correlated with bailateral TKA. RESULTS: In pairwise comparisons, the KL grade, FTA, %MA, JOA score, and knee flexion angle in the contralateral knee were significantly worse in the bilateral TKA group than in the unilateral TKA group after controlling for covariates (P < 0.01, respectively). A stepwise logistic regression revealed that significant contributors to undergoing the contralateral TKA were FTA (OR = 1.47, P < 0.001) and knee flexion angle (OR = 0.96, P = 0.022) of the contralateral knee. CONCLUSIONS: Severe varus deformity and limitations of flexion in the contralateral knee were found to be risk factors for undergoing additional TKA within one year of primary unilateral TKA among patients with knee OA.

Smartphone Use Is Associated with Low Prevalence of Locomotive Syndrome among Elderly Individuals with Musculoskeletal Disorders.

Objectives: Physical activity management through smartphone applications is increasing worldwide; however, it is unclear whether smartphone users among elderly Japanese individuals with musculoskeletal disorders are less likely to experience "locomotive syndrome" (LoS). We aimed to test the hypothesis that LoS in smartphone users had lower prevalence than that in non-smartphone users among elderly individuals with musculoskeletal disorders. Methods: Elderly participants, aged ≥60 years, who visited the outpatient clinic were enrolled. All participants were asked whether or not they used smartphones and were allocated into either the smartphone group or the non-smartphone group. After completing the 25-question Geriatric Locomotive Function Scale (GLFS-25), LoS prevalence was determined by 3-stage cutoff values of the GLFS-25 score (≥7, ≥16, and ≥24), and the total and three subdomain scores (body pain, movement-related difficulty, and psychosocial complications) were compared between the two groups. Generalized linear regression was then performed to confirm whether the use of smartphones was associated with lower GLFS-25 scores, even after controlling for confounders. Results: Overall, 266 participants, aged ≥60 years, were recruited. LoS prevalence was significantly higher in the non-smartphone group than in the smartphone group at all stages (all p < 0.001). Mean GLFS-25 total and subdomain scores were significantly lower in the smartphone group than in the non-smartphone group (all p < 0.001), and these statistical relationships were maintained even after controlling for age and sex. Conclusions: Smartphone use was associated with low LoS prevalence and low GLFS-25 scores among elderly individuals with musculoskeletal disorders, although the causal relationship remains unclear.

The Cut-off Value of Physical Activity for Undergoing Total Knee Arthroplasty in Patients with Knee Osteoarthritis.

BACKGROUND: We aimed to determine a cut-off value for physical activity (PA), measured using an accelerometer, between patients with knee osteoarthritis (OA) who decided to undergo total knee arthroplasty (TKA) and those who continued conservative treatment. METHODS: Forty-two participants were assigned to either a TKA group or a non-TKA group (21 per group). They were instructed to wear an accelerometer throughout the day. Average daily steps (steps/day), average daily time of light PA (LPA) (min/day), and average daily time of moderate-to-vigorous PA (MVPA) (min/day) were measured for seven days. Variables between the two groups were compared using univariate analyses, and then a stepwise logistic regression was conducted to determine which variables best correlated with undergoing TKA. The PA cut-offs were analysed using the receiver operating characteristic curve. RESULTS: Pain severity (p = 0.002), KL grade (p = 0.001), and MVPA (p = 0.012) differed significantly between the groups. The most useful cut-off value was 5.84 (min/day) for MVPA (AUC = 0.773), although only pain severity and KL grade were found to be significant contributors to undergoing TKA. CONCLUSIONS: Our results revealed there was a significant decrease in PA levels (MVPA cut-off, 5-6 min/day) in the TKA group compared with the non-TKA group.

Short-Chain Fatty Acid-Producing Gut Microbiota Is Decreased in Parkinson's Disease but Not in Rapid-Eye-Movement Sleep Behavior Disorder.

Gut dysbiosis has been repeatedly reported in Parkinson's disease (PD) but only once in idiopathic rapid-eye-movement sleep behavior disorder (iRBD) from Germany. Abnormal aggregation of α-synuclein fibrils causing PD possibly starts from the intestine, although this is still currently under debate. iRBD patients frequently develop PD. Early-stage gut dysbiosis that is causally associated with PD is thus expected to be observed in iRBD. We analyzed gut microbiota in 26 iRBD patients and 137 controls by 16S rRNA sequencing (16S rRNA-seq). Our iRBD data set was meta-analyzed with the German iRBD data set and was compared with gut microbiota in 223 PD patients. Unsupervised clustering of gut microbiota by LIGER, a topic model-based tool for single-cell RNA sequencing (RNA-seq) analysis, revealed four enterotypes in controls, iRBD, and PD. Short-chain fatty acid (SCFA)-producing bacteria were conserved in an enterotype observed in controls and iRBD, whereas they were less conserved in enterotypes observed in PD. Genus Akkermansia and family Akkermansiaceae were consistently increased in both iRBD in two countries and PD in five countries. Short-chain fatty acid (SCFA)-producing bacteria were not significantly decreased in iRBD in two countries. In contrast, we previously reported that recognized or putative SCFA-producing genera Faecalibacterium, Roseburia, and Lachnospiraceae ND3007 group were consistently decreased in PD in five countries. In α-synucleinopathy, increase of mucin-layer-degrading genus Akkermansia is observed at the stage of iRBD, whereas decrease of SCFA-producing genera becomes obvious with development of PD.IMPORTANCE Twenty studies on gut microbiota in PD have been reported, whereas only one study has been reported on iRBD from Germany. iRBD has the highest likelihood ratio to develop PD. Our meta-analysis of iRBD in Japan and Germany revealed increased mucin-layer-degrading genus Akkermansia in iRBD. Genus Akkermansia may increase the intestinal permeability, as we previously observed in PD patients, and may make the intestinal neural plexus exposed to oxidative stress, which can lead to abnormal aggregation of prion-like α-synuclein fibrils in the intestine. In contrast to PD, SCFA-producing bacteria were not decreased in iRBD. As SCFA induces regulatory T (Treg) cells, a decrease of SCFA-producing bacteria may be a prerequisite for the development of PD. We propose that prebiotic and/or probiotic therapeutic strategies to increase the intestinal mucin layer and to increase intestinal SCFA potentially retard the development of iRBD and PD.

Meta-Analysis of Gut Dysbiosis in Parkinson's Disease.

BACKGROUND: PD may begin with the intestinal accumulation of α-synuclein fibrils, which can be causally associated with gut dysbiosis. The variability of gut microbiota across countries prevented us from identifying shared gut dysbiosis in PD. OBJECTIVES: To identify gut dysbiosis in PD across countries. METHODS: We performed 16S ribosomal RNA gene sequencing analysis of gut microbiota in 223 patients with PD and 137 controls, and meta-analyzed gut dysbiosis by combining our dataset with four previously reported data sets from the United States, Finland, Russia, and Germany. We excluded uncommon taxa from our analyses. For pathway analysis, we developed the Kyoto Encyclopedia of Genes and Genomes orthology set enrichment analysis method. RESULTS: After adjusting for confounding factors (body mass index, constipation, sex, age, and catechol-O-methyl transferase inhibitor), genera Akkermansia and Catabacter, as well as families Akkermansiaceae, were increased, whereas genera Roseburia, Faecalibacterium, and Lachnospiraceae ND3007 group were decreased in PD. Catechol-O-methyl transferase inhibitor intake markedly increased family Lactobacillaceae. Inspection of these bacteria in 12 datasets that were not included in the meta-analysis revealed that increased genus Akkermansia and decreased genera Roseburia and Faecalibacterium were frequently observed across countries. Kyoto Encyclopedia of Genes and Genomes orthology set enrichment analysis revealed changes in short-chain fatty acid metabolisms in our dataset. CONCLUSIONS: We report that intestinal mucin layer-degrading Akkermansia is increased and that short-chain fatty acid-producing Roseburia and Faecalibacterium are decreased in PD across countries. © 2020 International Parkinson and Movement Disorder Society.

Properties of human dentin surface after ArF excimer laser irradiation.

Recently, improvement of the properties of dentin surface using dental lasers to increase bonding strength has been anticipated in the field of adhesive dentistry. The objective of this study was to investigate changes in the surface properties of human dentin after ArF excimer laser irradiation at different irradiation times, pulse repetition rates and energy densities. The SEM images of the irradiated surfaces were observed, and the contact angle and the roughness of the irradiated surface were measured. As a result, SEM demonstrated that the dentin surface became irregular following ArF excimer laser irradiation. When the energy density increased, the irregularity became more minute and dentinal tubules were more easily identified. By contrast, such changes were not observed when the irradiation time and pulse repetition rate were changed. Moreover, as energy densities increased, the contact angle tended to decrease and the surface roughness tended to increase. These results suggested that the area of the irradiated surface and wettability increased after irradiation with the ArF excimer laser. Consequently, irradiation with ArF excimer lasers could improve the surface properties and be potentially useful for adhesive dentistry.

[Time-dependence evaluation of the primary visual cortex by 1H MR-spectroscopy using a stimulation control system].

UNLABELLED: Proton magnetic resonance spectroscopy ((1)H MRS) is used to evaluate tumors and their remaining function under the assumption that event-related inspection and a method of data collection dependent on time are difficult. Therefore, this study examined the possibility that time depended on in MRS with a visual cortex. We conducted experiments using the following stimulations: REST: eyes are in a closed state, CONTROL: eyes are in an open state, and Continuous: consecutive stimulation and time dependence in the visual cortex. We enabled dependence in time by collecting data with a system that controlled stimulation and experimented on stimulation for a short time using this system. The results showed that no significant difference in metabolites was seen in the REST, CONTROL, and Consecutive stimulations. However, a significant difference was seen in Cr and NAA with time-dependent stimulation. Therefore, we considered functional magnetic resonance spectroscopy (fMRS) useful because time-dependent stimulation showed a meaningful difference with REST.

[Response by visual stimulation with the BOLD effect and motion artifact: identification of the activating signal and motion artifact].

This study used functional magnetic resonance imaging (fMRI) to evaluate brain function. fMRI data were collected by a block paradigm, and brain function was evaluated. However, irrelevant artifacts caused by the BOLD effect frequently occur in analytical processing. Therefore, there is a limit to obtaining an adequate activating reaction in the analytical system, which is normally equipped with MRI. However, there is a limit to obtaining a sufficient activating reaction in the analytical system, which is normally equipped with MRI. It has become standard practice to use an analytical system such as statistical parametric mapping (SPM). The response of movement of cerebrospinal fluid (CSF) artifact is high. Therefore, disappearance of the CSF artifact was done by statistical analysis. Then, the response of the signal from the beginning of stimulation was examined. As a result, the activating signal and the artifact signal could be identified.

Influence of moving sight by turning over frequency.

In late years, f-MRI (functional magnetic resonance imaging) are used for analysis of a visual function. In case of the study for a visual function, the checker flag pattern consists of white square and black square is usually used for sight stimulation. In sight stimulation using this pattern, a color of square (black and white) changes alternately at constant frequency. It is usually called pattern reversal stimulation. When this pattern is used for stimulation, the subject sometimes feels movement for the shown stimulation pattern. We think that this sensation of movement relates to spatial frequency (that means the size of a square of a stimulation pattern) of a stimulation image and a turning over frequency of a stimulation pattern strongly. Our objectives of this study are the following. 1) Clarify a part of the brain that is a cause of this moving sensation. 2) Investigate the relationship among the magnitude of this sensation, spatial frequency and turning over frequency. Three normal adults were used for the subject. This time, turning over frequency was changed to 8 Hz by 1 Hz step under fixed spatial frequency. Under this condition, we examined the state of activation of a V1 area. In addition, we examined whether BOLD effect varied with a change of a stimulation color. In this experiment, we used blue and yellow color instead of black and white for stimulation, and the reaction was examined.