Optimization of treatment strategy

The purpose of this study was to predict the survival time of patients with malignant glioma after radiotherapy with high accuracy by considering additional clinical factors and optimize the prescription dose and treatment duration for individual patient by using a machine learning model. A total of 35 patients with malignant glioma were included in this study. The candidate features included 12 clinical features and 192 dose–volume histogram (DVH) features. The appropriate input features and parameters of the support vector machine (SVM) were selected using the genetic algorithm based on Akaike’s information criterion, i.e. clinical, DVH, and both clinical and DVH features. The prediction accuracy of the SVM models was evaluated through a leave-one-out cross-validation test with residual error, which was defined as the absolute difference between the actual and predicted survival times after radiotherapy. Moreover, the influences of various values of prescription dose and treatment duration on the predicted survival time were evaluated. The prediction accuracy was significantly improved with the combined use of clinical and DVH features compared with the separate use of both features (P < 0.01, Wilcoxon signed rank test). Mean ± standard deviation of the leave-one-out cross-validation using the combined clinical and DVH features, only clinical features and only DVH features were 104.7 ± 96.5, 144.2 ± 126.1 and 204.5 ± 186.0 days, respectively. The prediction accuracy could be improved with the combination of clinical and DVH features, and our results show the potential to optimize the treatment strategy for individual patients based on a machine learning model

L-arginine stimulates fibroblast proliferation through the GPRC6A-ERK1/2 and PI3K/Akt pathway.

L-arginine is considered a conditionally essential amino acid and has been shown to enhance wound healing. However, the molecular mechanisms through which arginine stimulates cutaneous wound repair remain unknown. Here, we evaluated the effects of arginine supplementation on fibroblast proliferation, which is a key process required for new tissue formation. We also sought to elucidate the signaling pathways involved in mediating the effects of arginine on fibroblasts by evaluation of extracellular signal-related kinase (ERK) 1/2 activation, which is important for cell growth, survival, and differentiation. Our data demonstrated that addition of 6 mM arginine significantly enhanced fibroblast proliferation, while arginine deprivation increased apoptosis, as observed by enhanced DNA fragmentation. In vitro kinase assays demonstrated that arginine supplementation activated ERK1/2, Akt, PKA and its downstream target, cAMP response element binding protein (CREB). Moreover, knockdown of GPRC6A using siRNA blocked fibroblast proliferation and decreased phosphorylation of ERK1/2, Akt and CREB. The present experiments demonstrated a critical role for the GPRC6A-ERK1/2 and PI3K/Akt signaling pathway in arginine-mediated fibroblast survival. Our findings provide novel mechanistic insights into the positive effects of arginine on wound healing

Variability in Physical Inactivity Responses of University Students during COVID-19 Pandemic: A Monitoring of Daily Step Counts Using a Smartphone Application

This study investigated the changes in physical inactivity of university students during the COVID-19 pandemic, with reference to their academic calendar. We used the daily step counts recorded by a smartphone application (iPhone Health App) from April 2020 to January 2021 (287 days) for 603 participants. The data for 287 days were divided into five periods based on their academic calendar. The median value of daily step counts across each period was calculated. A k-means clustering analysis was performed to classify the 603 participants into subgroups to demonstrate the variability in the physical inactivity responses. The median daily step counts, with a 7-day moving average, dramatically decreased from 5000 to 2000 steps/day in early April. It remained at a lower level (less than 2000 steps/day) during the first semester, then increased to more than 5000 steps/day at the start of summer vacation. The clustering analysis demonstrated the variability in physical inactivity responses. The inactive students did not recover daily step counts throughout the year. Consequently, promoting physical activity is recommended for inactive university students over the course of the whole semester

Vibration acceleration promotes endochondral formation during fracture healing through cellular chondrogenic differentiation.

Vibration acceleration through whole body vibration has been reported to promote fracture healing. However, the mechanism responsible for this effect remains unclear. Purpose of this study was to determine whether vibration acceleration directly affects cells around the fracture site and promotes endochondral ossification. Four-week-old female Wistar Hannover rats were divided into two groups (vibration [V group] and control [C group]). The eighth ribs on both sides were cut vertically using scissors. From postoperative day 3 to 11, vibration acceleration using Power Plate® (30 Hz, low amplitude [30-Low], 10 min/day) was applied in the V group. Mature calluses appeared earlier in the V group than in the C group by histological analysis. The GAG content in the fracture callus on day 6 was significantly higher in the V group than in the C group. The mRNA expressions of SOX-9, aggrecan, and Col-II in the fracture callus on day 6 and Col-X on day 9 were significantly higher in the V group than in the C group. For in vitro analysis, four different conditions of vibration acceleration (30 or 50 Hz with low or high amplitude [30-Low, 30-High, 50-Low, and 50-High], 10 min/day) were applied to a prechondrogenic cell (ATDC5) and an undifferentiated cell (C3H10T1/2). There was no significant difference in cell proliferation between the control and any of the four vibration conditions for both cell lines. For both cell lines, alcian blue staining was greater under 30-Low and 50-Low conditions than under control as well as 30-High and 50-High conditions on days 7 and 14. Vibration acceleration under 30-L condition upregulated chondrogenic gene expressions of SOX-9, aggrecan, Col-II, and Col-X. Low-amplitude vibration acceleration can promote endochondral ossification in the fracture healing in vivo and chondrogenic differentiation in vitro

Vibration acceleration enhances proliferation, migration, and maturation of C2C12 cells and promotes regeneration of muscle injury in male rats

Abstract Vibration acceleration (VA) using a whole‐body vibration device is beneficial for skeletal muscles. However, its effect at the cellular level remains unclear. We aimed to investigate the effects of VA on muscles in vitro and in vivo using the C2C12 mouse myoblast cell line and cardiotoxin‐induced injury in male rat soleus muscles. Cell proliferation was evaluated using the WST/CCK‐8 assay and proportion of Ki‐67 positive cells. Cell migration was assessed using wound‐healing assay. Cell differentiation was examined by the maturation index in immunostained cultured myotubes and real‐time polymerase chain reaction. Regeneration of soleus muscle in rats was assessed by recruitment of satellite cells, cross‐sectional area of regenerated muscle fibers, number of centrally nucleated fibers, and conversion of regenerated muscle from fast‐ to slow‐twitch. VA at 30 Hz with low amplitude for 10 min promoted C2C12 cell proliferation, migration, and myotube maturation, without promoting expression of genes related to differentiation. VA significantly increased Pax7‐stained satellite cells and centrally nucleated fibers in injured soleus muscles on Day 7 and promoted conversion of fast‐ to slow‐twitch muscle fibers with an increase in the mean cross‐sectional area of regenerated muscle fibers on Day 14. VA enhanced the proliferation, migration, and maturation of C2C12 myoblasts and regeneration of injured rat muscles

Effects of l-arginine stimulation on the activities of ERK, Akt, PKA and CREB.

<p>(A, B, C, D) ERK, Akt, PKA and CREB activities were analyzed by immunoblotting at 5, 15, and 30 min after stimulation with 6 mM l-arginine. Densitometry measurements for p-ERK, p-Akt, p-PKA and p-CREB were normalized to the amount of total ERK, Akt, PKA and CREB, respectively. (E) Fibroblasts were treated with 10 μM U0126, and then cells were stimulated with 6 mM l-arginine. The activities of CREB were analyzed by immunoblotting. Results are presented as the fold change compared with untreated cells. Data are expressed as the mean ± SEM of 3 independent experiments (*<i>p</i><0.05, **<i>p</i><0.01, Tukey’s post hoc test).</p

Effects of inhibition of ERK, Akt, PKA, CREB and GPRC6A on the proliferation of l-arginine-treated fibroblasts.

<p>Fibroblast proliferation was measured by MTS assay after pretreatment with 0 or 6l-arginine and subsequent treatment with 10 μM U0126, LY294002, H-89, siRNA CREB and siRNA GPRC6A. Results are expressed as the mean ± SEM of 3 independent experiments.</p

Effects of knockdown of GPRC6A on the activities of ERK, Akt, PKA and CREB in l-arginine-treated fibroblasts.

<p>(A, B, C, D) Fibroblasts were treated with si RNA GPRC6A and then cells were stimulated with 6 mM l-arginine. The activities of ERK, Akt, PKA and CREB were analyzed by immunoblotting. Densitometry measurements for p-ERK, p-Akt, p-PKA and p-CREB were normalized to the amount of total ERK, Akt, PKA, and CREB, respectively. Results are presented as the fold change compared with the control group. Data are expressed as the mean ± SEM of 3 independent experiments (**<i>p</i><0.01, Tukey’s post hoc test).</p