Efficient Myogenic Activities Achieved through Blade-Casting-Assisted Bioprinting of Aligned Myoblasts Laden in Collagen Bioink.

This study investigated mechanical stimulation combined with three-dimensional (3D) bioprinting as a new approach for introducing biophysical and biological cues for tissue regeneration. A blade-casting method in conjunction with bioprinting was employed to fabricate bioengineered skeletal muscle constructs using a bioink composed of C2C12 myoblasts and collagen type-I. Various printing process parameters were selected and optimized to achieve a highly organized cell alignment within the constructs. The resulting cell-aligned constructs demonstrated remarkable improvement in actin filament alignment and cell proliferation compared with conventionally printed cell-laden constructs. This improvement can be attributed to the synergistic effects of mechanotransduction, facilitating the cellular response to mechanical cues and the alignment of fibrillated collagen, which plays a significant role in modulating cellular functions and promoting muscle tissue regeneration. Furthermore, we assessed the impact of blade casting combined with 3D bioprinting on gene expression. The expression levels of myogenesis-related genes were substantially upregulated, with an approximately 1.6-fold increase compared to the constructs fabricated without the blade-casting technique. The results demonstrated the effectiveness of combining mechanical stimulation through blade casting with 3D bioprinting in promoting aligned cell structures, enhancing cellular functions, and driving muscle tissue regeneration.

Upregulation of LAMB1 via ERK/c-Jun Axis Promotes Gastric Cancer Growth and Motility.

Gastric cancer is the fifth most common cancer worldwide with a poor survival rate. Therefore, it is important to identify predictive and prognostic biomarkers of gastric cancer. Laminin subunit beta 1 (LAMB1) is involved in attachment, migration, and organization during development, and its elevated expression has been associated with several cancers. However, the role and mechanism of LAMB1 in gastric cancer remains unknown. Here, we determined that LAMB1 is upregulated in gastric cancer tissues and contributes to cell growth and motility. Using a public database, we showed that LAMB1 expression was significantly upregulated in gastric cancer compared to normal tissues. LAMB1 was also found to be associated with poor prognosis in patients with gastric cancer. Overexpression of LAMB1 elevated cell proliferation, invasion, and migration; however, knockdown of LAMB1 decreased these effects in gastric cancer cells. U0126, an extracellular signal-regulated kinase (ERK) inhibitor, regulated the expression of LAMB1 in gastric cancer cells. Additionally, we showed that c-Jun directly binds to the LAMB1 promoter as a transcription factor and regulates its gene expression via the ERK pathway in gastric cancer cells. Therefore, our study indicates that LAMB1 promotes cell growth and motility via the ERK/c-Jun axis and is a potential biomarker and therapeutic target of gastric cancer.

A Myoblast-Laden Collagen Bioink with Fully Aligned Au Nanowires for Muscle-Tissue Regeneration.

Contact guidance can promote cell alignment and is thus widely employed in tissue regeneration. In particular, skeletal muscle consists of long fibrous bundles of multinucleated myotubes formed by the fusion and differentiation of the satellite cells of myoblasts. Herein, a functional bioink and cell-printing process supplemented with an electric field are proposed for obtaining highly aligned myoblasts in a collagen-based bioink. To achieve the goal, we mixed Au nanowires (GNWs) with the collagen-based bioink to provide aligned topographical cues to the laden cells. Because the aligned GNWs could clearly provide topographical cues to the cells, we adjusted various processing parameters (flow rate, nozzle speed, and processing temperature) and applied an external electric field to optimally align the GNWs. By selecting an appropriate condition, the GNWs in the printed C2C12-laden structure were well aligned in the printing direction, and they eventually induced a high degree of myoblast alignment and efficient myotube formation. Through the several in vitro cellular activities and in vivo works revealing the myogenesis of the cell-laden structure, we conclude that the collagen/GNW-based cell-laden structure fabricated using the proposed method is a new prospective platform for the effective formation of muscle tissues.

Tumor-Stroma Crosstalk Enhances REG3A Expressions that Drive the Progression of Hepatocellular Carcinoma.

BACKGROUND: Crosstalk between tumors and their microenvironment plays a crucial role in the progression of hepatocellular carcinoma (HCC). However, there is little existing information about the key signaling molecule that modulates tumor-stroma crosstalk. METHODS: Complementary DNA (cDNA) microarray analysis was performed to identify the key molecule in tumor-stroma crosstalk. Subcutaneous xenograft in vivo murine model, immunoblotting, immunofluorescence, and real-time polymerase chain reaction using HCC cells and tissues were performed. RESULTS: The key molecule, regenerating gene protein-3A (REG3A), was most significantly enhanced when coculturing HCC cells and activated human hepatic stellate cells (HSCs) (+8.2 log) compared with monoculturing HCC cells using cDNA microarray analysis. Downregulation of REG3A using small interfering RNA significantly decreased the proliferation of HSC-cocultured HCC cells in vitro and in vivo, and enhanced deoxycholic acid-induced HCC cell apoptosis. Crosstalk-induced REG3A upregulation was modulated by platelet-derived growth factor ßß (PDGF-ßß) in p42/44-dependent manner. REG3A mRNA levels in human HCC tissues were upregulated 1.8-fold compared with non-tumor tissues and positively correlated with PDGF-ßß levels. CONCLUSIONS: REG3A/p42/44 pathway/PDGF-ßß signaling plays a significant role in hepatocarcinogenesis via tumor-stroma crosstalk. Targeting REG3A is a potential novel therapeutic target for the management of HCCs by inhibiting crosstalk between HCC cells and HSCs.

Effect of neuromuscular electrical stimulation on lip strength and closure function in patients with dysphagia after stroke.

[Purpose] This study aimed to investigate the effect of neuromuscular electrical stimulation (NMES) on lip strength and closure function of patients with dysphagia after stroke. [Subjects and Methods] Eight patients with dysphagia were recruited. NMES was applied to the orbicularis oris muscle. All the participants received NMES for 30 min/d, 5 d/wk, for 4 weeks. Lip strength was measured using the Iowa Oral Performance Instrument. To assess lip closure, the lip closure subitem of the videofluoroscopic dysphagia scale was used. [Results] Lip strength showed significant improvement and lip closure function showed a significant decrease. [Conclusion] This study demonstrates that NMES is useful for improving lip strength and closure function.

Differences in maximal strength and endurance of the tongue according to region in healthy adults.

[Purpose] The purpose of this study was to identify differences in maximal strength and endurance of the tongue among healthy adults. [Subjects and Methods] A total of 60 healthy volunteers (30 men; 30 women; age range, 20-26 years) were recruited and evaluated for maximal strength and endurance of the anterior and posterior regions of the tongue using the Iowa Oral Performance Instrument. [Results] Tongue strength in the anterior region was greater than that in the posterior region. In contrast, tongue endurance in the posterior region was greater than that in the anterior region. [Conclusion] In conclusion, these results confirm that the anterior region of the tongue exhibits greater strength, whereas the posterior region exhibits greater endurance.

The effects of tongue stretching exercise on tongue length in healthy adults: a preliminary study.

[Purpose] The purpose of this study was to investigate the effects of tongue stretching exercise on the tongue length of healthy adults. [Subjects and Methods] This study recruited 6 healthy adults. They were treated for 4 weeks with tongue stretching. The change in tongue length during tongue protrusion before and after intervention was measured using a ruler. [Results] All 6 participants showed increased tongue length (minimum 20 mm to maximum 40 mm). [Conclusion] This study confirms that tongue stretching is a useful method to increase tongue length.

Effect of motor imagery training and electromyogram-triggered neuromuscular electrical stimulation on lower extremity function in stroke patients: a pilot trial.

[Purpose] To investigate the effect of motor imagery training and electromyogram-triggered neuromuscular electrical stimulation (MIT-EMG NMES) on the lower extremity function of stroke patients. [Subjects and Methods] This study recruited eight patients with hemiplegia due to stroke. All patients received MIT-EMG NMES for 20 min daily, 5 days per week for 4 weeks. Lower extremity function were assessed using the timed up-and-go (TUG) and 10-meter walk (10MW) tests. [Results] The results of TUG test decreased significantly from 20.5 ± 4.5 to 14.0 ± 3.5 s, while those of 10 MW test showed a significant decrease from 21.3 ± 4.5 to 15.5 ± 3.2 m. [Conclusion] This study suggests that MIT-EMG NMES is a new rehabilitation therapy for lower extremity recovery in hemiplegic stroke patients.

Effects of jaw opening exercise on aspiration in stroke patients with dysphagia: a pilot study.

[Purpose] The purpose of this study was to investigate the effect of jaw opening exercise (JOE) on aspiration in patients with dysphagia after stroke. [Subjects and Methods] Three subjects were recruited. Isometric and isotonic JOE were performed using a rubber ball, 5 days a week for 4 weeks. Aspiration was evaluated using the penetration-a spiration scale (PAS) based on a videofluoroscopic swallowing study. [Results] All subjects showed a score reduction of at least 1 point and a maximum reduction of 2 points in the PAS in the liquid type. [Conclusion] This study confirmed that JOE can be used to reduce aspiration in patients with dysphagia after stroke.

Taping of the elbow extensor muscle in chronic stroke patients: comparison between before and after three-dimensional motion analysis.

[Purpose] This study aimed to observe the effect of kinesio taping on the quality of movement of each arm during a reaching task in patients with right-sided hemiparetic stroke. [Subjects and Methods] Sixteen right-handed participants who had had a right-sided hemiparetic stroke were requested to perform a reaching task with each arm, with and without kinesio taping. A three-dimensional motion analysis system was used to measure peak angular velocity, time to reach peak angular velocity, and movement units during elbow motion. [Results] In the right arm, movements during the reaching task with kinesio taping were faster, smoother, and more efficient than those without kinesio taping. The peak angular velocity increased, and the time to reach peak angular velocity decreased. Movement units decreased significantly. However, in the untaped arm, the movement was slower, rougher, and less efficient. [Conclusion] Kinesio taping provided a positive effect on the reaching movement of the taped arm of right-handed persons who had had a right-sided hemiparetic stroke.

Effects of combining mental practice with electromyogram-triggered electrical stimulation for stroke patients with unilateral neglect.

[Purpose] The aim of this study was to investigate the effect of mental practice combined with electromyogram-triggered electrical stimulation on neglect and activities of daily living in stroke patients with unilateral neglect. [Subjects and Methods] Thirty-three stroke patients with unilateral neglect were recruited from a local university hospital, and were divided into two groups. The experimental group received an intervention consisting of mental practice combined with electromyogram-triggered electrical stimulation on the neglected side, while the control group received cyclic electrical stimulation at the same site. In addition, both groups received an identical intervention of conventional occupational and physical therapy. [Results] After the intervention, the experimental group showed a statistically significant improvement in the line bisection test result, star cancellation test result, and Catherine Bergego Scale scores. The control group showed a significant improvement only in the line bisection test result. [Conclusion] These data suggest that mental practice combined with electromyogram-triggered electrical stimulation is an effective, novel treatment for reducing unilateral neglect in stroke patients.

Effects of a Community-based Fall Prevention Exercise Program on Activity Participation.

This study was conducted to identify the effects of a fall-prevention exercise program on the participation and static balance of elderly persons in daily life roles. [Subjects] Ten participants over 65 years of age (75.29±2.93) who were healthy community-dwellers (two men and eight women) were recruited. [Methods] The participants exercised three times a week for eight weeks. The exercise program was based on the fitness and mobility exercise (FAME) protocol. The outcome measures were changes in activity participation level and the fall index. [Results] After the exercise, the activity participation level significantly increased, and the fall index significantly decreased. [Conclusion] A fall prevention exercise program can have a positive effect on participation and static balance in older adults.

Engineered 3D liver-tissue model with minispheroids formed by a bioprinting process supported with in situ electrical stimulation.

Three-dimensional (3D) bioprinting, an effective technique for building cell-laden structures providing native extracellular matrix environments, presents challenges, including inadequate cellular interactions. To address these issues, cell spheroids offer a promising solution for improving their biological functions. Particularly, minispheroids with 50-100 µm diameters exhibit enhanced cellular maturation. We propose a one-step minispheroid-forming bioprinting process incorporating electrical stimulation (E-MS-printing). By stimulating the cells, minispheroids with controlled diameters were generated by manipulating the bioink viscosity and stimulation intensity. To validate its feasibility, E-MS-printing process was applied to fabricate an engineered liver model designed to mimic the hepatic lobule unit. E-MS-printing was employed to print the hepatocyte region, followed by bioprinting the central vein using a core-shell nozzle. The resulting constructs displayed native liver-mimetic structures containing minispheroids, which facilitated improved hepatic cell maturation, functional attributes, and vessel formation. Our results demonstrate a new potential 3D liver model that can replicate native liver tissues.

An unsupervised two-step training framework for low-dose computed tomography denoising.

BACKGROUND: Although low-dose computed tomography (CT) imaging has been more widely adopted in clinical practice to reduce radiation exposure to patients, the reconstructed CT images tend to have more noise, which impedes accurate diagnosis. Recently, deep neural networks using convolutional neural networks to reduce noise in the reconstructed low-dose CT images have shown considerable improvement. However, they need a large number of paired normal- and low-dose CT images to fully train the network via supervised learning methods. PURPOSE: To propose an unsupervised two-step training framework for image denoising that uses low-dose CT images of one dataset and unpaired high-dose CT images from another dataset. METHODS: Our proposed framework trains the denoising network in two steps. In the first training step, we train the network using 3D volumes of CT images and predict the center CT slice from them. This pre-trained network is used in the second training step to train the denoising network and is combined with the memory-efficient denoising generative adversarial network (DenoisingGAN), which further enhances both objective and perceptual quality. RESULTS: The experimental results on phantom and clinical datasets show superior performance over the existing traditional machine learning and self-supervised deep learning methods, and the results are comparable to the fully supervised learning methods. CONCLUSIONS: We proposed a new unsupervised learning framework for low-dose CT denoising, convincingly improving noisy CT images from both objective and perceptual quality perspectives. Because our denoising framework does not require physics-based noise models or system-dependent assumptions, our proposed method can be easily reproduced; consequently, it can also be generally applicable to various CT scanners or dose levels.

Effect of Pressure on Ce-Substituted Nd-Fe-B Hot-Deformed Magnets in the Hot-Pressing Process.

With the increasing demand for Nd-Fe-B magnets across various applications, the cost-effective substitution of Ce has garnered significant interest. Many studies have been conducted to achieve the high magnetic properties of Nd-Ce-Fe-B hot deformation magnets in which Nd is replaced with Ce. We propose a method to improve magnetic properties of the Ce-substituted Nd-Ce-Fe-B hot-deformed magnets by optimizing the hot-pressing process. This study investigates the microstructure and properties following hot deformation of Ce-substituted Nd-Ce-Fe-B magnets fabricated at a constant temperature and different pressures (100-300 MPa) during the hot-pressing process. The results highlight the influence of pressure from previous hot-pressing processes on grain alignment and microstructure during hot deformation. Magnets subjected to hot pressing at 200 MPa followed by hot deformation achieved superior magnetic properties, with Hci = 8.9 kOe, Br = 12.2 kG, and (BH)max = 31 MGOe with 40% of Nd replaced with Ce. Conversely, precursors prepared at 100 MPa exhibited low density due to high porosity, resulting in poor microstructure and magnetic properties after hot deformation. In magnets using precursors prepared at 300 MPa, coarsened grains and a condensed h-RE2O3 phase were observed. Incorporating Ce into the magnets led to insufficient formation of RE-rich phases due to the emergence of REFe2 secondary phases, disrupting grain alignment and hindering the homogeneous distribution of the RE-rich phase essential for texture formation. Precursors prepared under suitable pressure exhibited uniform distribution of the RE-rich phase, enhancing grain alignment along the c-axis and improving magnetic properties, particularly remanence. In conclusion, our findings present a strategy for achieving the ideal microstructure and magnetic properties of hot-deformed magnets with high Ce contents.

Fetal abdominal obesity in women with one value abnormality on diagnostic test for gestational diabetes mellitus.

Previous studies have shown that fetal abdominal obesity (FAO) was already observed at the time of gestational diabetes mellitus (GDM) diagnosis and persisted until delivery despite management in older and/or obese women. In this study, we investigated whether fetuses of women with milder hyperglycemia than GDM have accelerated abdominal growth, leading to adverse pregnancy outcomes. We retrospectively reviewed the medical records of 7,569 singleton pregnant women who were universally screened using a 50-g glucose challenge test (GCT) and underwent a 3-h 100-g oral glucose tolerance test (OGTT) if GCT result was ≥140mg/dL. GDM, one value abnormality (OVA), and normal glucose tolerance (NGT, NGT1: GCT negative, NGT2: GCT positive & OGTT negative) were diagnosed using Carpenter-Coustan criteria. With fetal biometry data measured simultaneously with 50-g GCT, relative fetal abdominal overgrowth was investigated by assessing the fetal abdominal overgrowth ratios (FAORs) of the ultrasonographically estimated gestational age (GA) of abdominal circumference(AC) per actual GA by the last menstruation period(LMP), biparietal diameter(BPD) or femur length(FL), respectively. FAO was defined as FAOR ≥90th percentile The FAORs of GA-AC/GA-LMP and GA-AC/GA-BPD were significantly higher in OVA subjects compared to NGT subjects but not in NGT2 subjects. Although the frequency of FAO in OVA (12.1%) was between that of NGT (9.6%) and GDM (18.3%) without statistically significant difference, the prevalence of large for gestational age at birth and primary cesarean delivery rates were significantly higher in OVA (9.8% and 29.7%) than in NGT (5.1% and 21.5%, p<0.05). Particularly, among OVA subjects with FAO, the prevalence (33.3% and 66.7%) was significantly higher than in those without FAO (9.7% and 24.2%, p<0.05). The degree of fetal abdominal growth acceleration in OVA subjects was intermediate between that of NGT and GDM subjects. OVA subjects with FAO at the time of GDM diagnosis were strongly associated with adverse pregnancy outcomes.

Tumor-on-a-chip models combined with mini-tissues or organoids for engineering tumor tissues.

The integration of tumor-on-a-chip technology with mini-tissues or organoids has emerged as a powerful approach in cancer research and drug development. This review provides an extensive examination of the diverse biofabrication methods employed to create mini-tissues, including 3D bioprinting, spheroids, microfluidic systems, and self-assembly techniques using cell-laden hydrogels. Furthermore, it explores various approaches for fabricating organ-on-a-chip platforms. This paper highlights the synergistic potential of combining these technologies to create tumor-on-a-chip models that mimic the complex tumor microenvironment and offer unique insights into cancer biology and therapeutic responses.

Flexible Dry Electrode Based on a Wrinkled Surface That Uses Carbon Nanotube/Polymer Composites for Recording Electroencephalograms.

Electroencephalography (EEG) captures minute electrical signals emanating from the brain. These signals are vulnerable to interference from external noise and dynamic artifacts; hence, accurately recording such signals is challenging. Although dry electrodes are convenient, their signals are of limited quality; consequently, wet electrodes are predominantly used in EEG. Therefore, developing dry electrodes for accurately and stably recording EEG signals is crucial. In this study, we developed flexible dry electrodes using polydimethylsiloxane (PDMS)/carbon-nanotube (CNT) composites with isotropically wrinkled surfaces that effectively combine the advantages of wet and dry electrodes. Adjusting the PDMS crosslinker ratio led to good adhesion, resulting in a highly adhesive CNT/PDMS composite with a low Young's modulus that exhibited excellent electrical and mechanical properties owing to its ability to conformally contact skin. The isotropically wrinkled surface also effectively controls dynamic artifacts during EEG signal detection and ensures accurate signal analysis. The results of this study demonstrate that dry electrodes based on flexible CNT/PDMS composites and corrugated structures can outperform wet electrodes. The introduction of such electrodes is expected to enable the accurate analysis and monitoring of EEG signals in various scenarios, including clinical trials.

DNA Hypermethylation Inhibits the CD82 Metastasis Suppressor Gene in Gastric Cancer.

BACKGROUND/AIM: Gastric cancer, with its high global incidence and mortality rates, poses a significant challenge due to the rapid decline in patient survival upon metastasis. Understanding and combating metastasis are crucial in improving outcomes. The metastasis suppressor gene CD82 has demonstrated efficacy in inhibiting metastasis across various carcinomas but is frequently down-regulated. However, its role and regulatory mechanisms in gastric cancer remain elusive. MATERIALS AND METHODS: Utilizing public data, we assessed patient survival in relation to CD82 expression. CD82 expression in gastric cancer cell lines was evaluated via western blotting, and its impact on cell mobility was assessed through wound healing and Transwell assays. The demethylation of CD82 was induced using 5-aza-deoxycytidine, while methylation levels were detected via methylation-specific PCR. RESULTS: Low CD82 expression correlated with poor prognosis in patients, and down-regulation and over-expression of CD82 significantly affected cell mobility. Treatment with 5-aza-deoxycytidine restored CD82 expression in low-expressing cell lines, highlighting its methylation-dependent regulation. CONCLUSION: CD82 serves as a pivotal regulator of cell mobility in gastric cancer by suppressing metastasis. Its expression is attenuated in gastric cancer cells through promoter hypermethylation.

Impact of glucose metabolism on PD-L1 expression in sorafenib-resistant hepatocellular carcinoma cells.

Hepatocellular carcinoma (HCC) is the fifth leading cause of cancer-related mortality worldwide. Programmed cell death ligand-1 (PD-L1) is an immune checkpoint protein that binds to programmed cell death-1 (PD-1), which is expressed in activated T cells and other immune cells and has been employed in cancer therapy, including HCC. Recently, PD-L1 overexpression has been documented in treatment-resistant cancer cells. Sorafenib is a multikinase inhibitor and the only FDA-approved treatment for advanced HCC. However, several patients exhibit resistance to sorafenib during treatment. This study aimed to assess the effect of glucose deprivation on PD-L1 expression in HCC cells. We used PD-L1-overexpressing HepG2 cells and IFN-γ-treated SK-Hep1 cells to explore the impact of glycolysis on PD-L1 expression. To validate the correlation between PD-L1 expression and glycolysis, we analyzed data from The Cancer Genome Atlas (TCGA) and used immunostaining for HCC tissue analysis. Furthermore, to modulate PD-L1 expression, we treated HepG2, SK-Hep1, and sorafenib-resistant SK-Hep1R cells with rapamycin. Here, we found that glucose deprivation reduced PD-L1 expression in HCC cells. Additionally, TCGA data and immunostaining analyses confirmed a positive correlation between the expression of hexokinase II (HK2), which plays a key role in glucose metabolism, and PD-L1. Notably, rapamycin treatment  decreased the expression of PD-L1 and HK2 in both high PD-L1-expressing HCC cells and sorafenib-resistant cells. Our results suggest that the modulation of PD-L1 expression by glucose deprivation may represent a strategy to overcome PD-L1 upregulation in patients with sorafenib-resistant HCC.