Enhancement of natural killer cell cytotoxicity by using static magnetic field to increase their viability.

Natural killer (NK) cells are innately immune to the body's immune system and can actively recognize and kill cancer cells. This study explores the potential for enhancing the killing ability of NK cells by co-culturing the NK cells with the target cells under a static magnetic field (SMF). In this study, NK92-MI cell lines were cultured in the presence of a 0.4-T SMF. The effect of the SMF on NK cell viability was evaluated by means of an MTT assay. Culturing tests were performed with inhibitors of the DAG/IP3, STAT3, ERK, JNK and p38 pathways in order to examine the possible signaling cascade responsible for the SMF effect on the NK92-MI cell viability. Finally, the effect of the SMF on the cytotoxicity of the NK92-MI cells was evaluated by co-culturing the NK cells with K562 leukemia cell lines. The results showed that the application of a 0.4-T SMF significantly increased (p < 0.05) the viability of the NK92-MI cells. Furthermore, the inhibitor tests indicated that the SMF affected cell viability by activating multiple MAPK signaling pathways (ERKs, JNKs, and p38-MAPK). Finally, SMF pre-exposure for 48 hr significantly improved the killing activity of the NK92-MI cells (p < 0.05). That is, pre-exposure to SMF increased the viability of the NK92-MI cells and improved their killing ability against K562 tumor cells. In general, the present results suggest that NK cells pre-exposed to 0.4-T SMF show potential as a tool for immune-therapy treatment of cancer.

Static magnetic field increases survival rate of dental pulp stem cells during DMSO-free cryopreservation.

Successful and efficient cryopreservation of living cells and organs is a key clinical application of regenerative medicine. Recently, magnetic cryopreservation has been reported for intact tooth banking and cryopreservation of dental tissue. The aim of this study was to assess the cryoprotective effects of static magnetic fields (SMFs) on human dental pulp stem cells (DPSCs) during cryopreservation. Human DPSCs isolated from extracted teeth were frozen with a 0.4-T or 0.8-T SMF and then stored at -196 °C for 24 h. During freezing, the cells were suspended in freezing media containing with 0, 3 or 10% DMSO. After thawing, the changes in survival rate of the DPSCs were determined by flow cytometry. To understand the possible cryoprotective mechanisms of the SMF, the membrane fluidity of SMF-exposed DPSCs was tested. The results showed that when the freezing medium was DMSO-free, the survival rates of the thawed DPSCs increased 2- or 2.5-fold when the cells were exposed to 0.4-T or 0.8-T SMFs, respectively (p < 0.01). In addition, after exposure to the 0.4-T SMF, the fluorescence anisotropy of the DPSCs increased significantly (p < 0.01) in the hydrophilic region. These results show that SMF exposure improved DMSO-free cryopreservation. This phenomenon may be due to the improvement of membrane stability for resisting damage caused by ice crystals during the freezing procedure.

Interaction between the albumin-bilirubin score and nutritional risk index in the prediction of post-hepatectomy liver failure.

BACKGROUND: Post-hepatectomy liver failure (PHLF) is the most common postoperative complication and the leading cause of death after hepatectomy. The albumin-bilirubin (ALBI) score and nutritional risk index (NRI) have been shown to assess end-stage liver disease and predict PHLF and patient survival. We hypothesized that the ALBI score and NRI interact in the prediction of PHLF. AIM: To analyze the interaction between the ALBI score and NRI in PHLF in patients with hepatocellular carcinoma. METHODS: This retrospective study included 186 patients who underwent hepatectomy for hepatocellular carcinoma at the Affiliated Hospital of Youjiang Medical University for Nationalities between January 2020 and July 2023. Data on patient characteristics and laboratory indices were collected from their medical records. Univariate and multivariate logistic regression were performed to determine the interaction effect between the ALBI score and NRI in PHLF. RESULTS: Of the 186 patients included in the study, PHLF occurred in 44 (23.66%). After adjusting for confounders, multivariate logistic regression identified ALBI grade 2/3 [odds ratio (OR) = 73.713, 95% confidence interval (CI): 9.175-592.199] and NRI > 97.5 (OR = 58.990, 95%CI: 7.337-474.297) as risk factors for PHLF. No multiplicative interaction was observed between the ALBI score and NRI (OR = 0.357, 95%CI: 0.022-5.889). However, the risk of PHLF in patients with ALBI grade 2/3 and NRI < 97.5 was 101 times greater than that in patients with ALBI grade 1 and NRI ≥ 97.5 (95%CI: 56.445-523.839), indicating a significant additive interaction between the ALBI score and NRI in PHLF. CONCLUSION: Both the ALBI score and NRI were risk factors for PHLF, and there was an additive interaction between the ALBI score and NRI in PHLF.

Chromatin modified protein 4C (CHMP4C) facilitates the malignant development of cervical cancer cells.

Despite improvements in prevention and treatment, cervical cancer (CC) still poses a serious threat to women's health. CHMP4C (chromatin modified protein 4C) is a subunit of the endosomal sorting complex required for transport, which is expressed in both nucleus and cytoplasm. Here, we examined the effect of CHMP4C on the biological behavior of CC cells and the underlying mechanisms. We report that CHMP4C expression is higher in CC tissues, and high CHMP4C expression is associated with lower survival. Up-regulation of CHMP4C in C-33A cells accelerates cell proliferation, migration and invasion, whereas down-regulation of CHMP4C in Ca Ski cells had the opposite effect. Moreover, overexpression of CHMP4C induced activation of the epithelial-mesenchymal transition pathway, whereas depletion of CHMP4C inhibited activation. Our results suggest that CHMP4C contributes to the viability and motility of CC cells by modulating epithelial-mesenchymal transition and may facilitate the identification of novel biomarkers for CC therapy.

Static magnetic field attenuates mortality rate of mice by increasing the production of IL-1 receptor antagonist.

PURPOSES: Disseminated intravascular coagulation (DIC) is a complex systemic thrombohemorrhagic disorder involving intravascular coagulation and hemorrhage. The aim of this study is to test whether static magnetic field (SMF) is effective in attenuating lipopolysaccharide (LPS)-induced DIC. MATERIALS AND METHODS: In vivo experiments were performed in this study using male BALB/cByJ mice. An intraperitoneal injection of 50 mg/kg LPS was shown to lead to approximately 50% mortality and this dose was used in subsequent experiments. To test the effects of SMF on the survival rate of LPS-induced animals, the mice were exposed to 0.25-T SMF for 2 h before LPS injection. In addition, the effect of a 2-h SMF treatment on the production of anti-inflammatory cytokines was evaluated. RESULTS: In the first set of experiments, we found that the survival rate was higher in the SMF-exposed group than in the sham-exposed group. The circulating platelet (PLT) counts in the SMF-exposed mice were significantly higher than in the unexposed animals. However, no significant changes in inflammatory cytokine, including tumour necrosis factor-alpha (TNF-alpha), interleukin-1alpha (IL-1alpha), interleukin-6 (IL-6) and monocyte chemotactic protein 1 (MCP-1), in plasma were found after SMF treatment. The results from the second experiment showed that the plasma levels of interleukin-1 receptor antagonist (IL-1ra) were higher in the SMF-exposed group than in the sham group. CONCLUSIONS: Exposure to an SMF increases the plasma levels of IL-1ra. This effect may inhibit the reduction in PLT in plasma, resulting in prevention in LPS induced DIC.

Mechanobiology of MG63 osteoblast-like cells adaptation to static magnetic forces.

The aim of this study was to explore the biophysical effects of static magnetic field on osteoblastic cells. MG63 cells were exposed to 0.25 and 0.4-T static magnetic fields (SMF). The cell cycle effects were tested by flow cytometry. The differentiation of the cells was assessed by detecting the changes in prostaglandin E2, osteocalcin, and extracellular matrix expression. Membrane fluidity was used to evaluate the alterations in the biophysical properties of cellular membranes after the SMF simulations. Our results show that SMF exposure increases prostaglandin E2 level and extracellular matrix express in MG63 cells. On the other hand, MG63 cells exposed to 0.4-T SMF exhibited a significant decrease in membrane fluidity at 8 h. Based on these findings, it appears reasonable to suggest that SMF affect osteoblastic maturation by increasing membrane rigidity and then inducing differentiation pathway.

Photoelastic analysis of stress distributions in the root-bone interface when applying various orthodontic methods to subside lower anterior crowding.

Dental crowding is a prevalent problem in modern society. Various factors, including different bracket systems and geometry of wire, influence the outcome using superelastic wire in the alignment stage of treatment. Currently, the use of light round wire instead of large-sized rectangular wire is emphasized to avoid powerful torsional stiffness. However, these guidelines lack scientific evidence for support. They have been written predominantly based on clinical experience. Therefore, the purpose of this study was to evaluate how factors such as bracket systems and wire geometry affect the stress distribution at the root-bone interface. Models using a photoelastic material (PL-3) to simulate bone tissue were fabricated. The simulated teeth were arranged as in lower anterior crowding. Then, the crowded teeth were subjected to orthodontic treatment with various types of bracket, ligating approaches using ligature wires of different sizes, shapes, and materials. Photoelastic images of the bone area of the models were obtained and compared. The results showed that wire size plays a more significant role than the material or cross-sectional shape of the wire in affecting the stress distribution at the simulated root-bone interface. The teeth ligated with a larger cross-sectional diameter of wire showed the application of excessive torque, which may cause root resorption and slow down tooth movement. These results not only demonstrate the scientific evidence backing clinical experience but also can be a useful reference for further clinical application.

Vibrational analysis of mandible trauma: experimental and numerical approaches.

The aim of this study was to evaluate the effectiveness of vibrational assessment of the mandible fracture patterns. Measurement of natural frequencies and associated vibrational mode shapes was performed to determine the relationship between the dynamic behavior of the human mandible and incidence of mandibular fractures using both in vitro modal testing and finite element analysis. Our results show that the natural frequencies of the human mandible in dry and wet conditions are 567 Hz and 501 Hz, respectively. The first vibrational mode of human mandible is a bending vibration with nodes located at the mandibular body where bone fracture is less likely to occur. By contrast, high vibration amplitudes were identified in the symphysis/parasymphysis and subcondyle regions where bone fractures tend occur. These findings indicate that the vibrational characteristics of the mandible are potential parameters for assessment of the mechanisms of injury.

Detection of looseness degree of dental posts using natural frequency analysis.

This study examines the relationship between the retention force and natural frequency of dental posts cemented with zinc phosphate cement. Forty-two decoronated maxillary incisors were collected and embedded in resin blocks. The 7-mm post spaces were prepared for all test samples prior to cementing the 13-mm Para-Posts with zinc phosphate cement. The natural frequency values and retention forces of the zinc phosphate cement-cemented Para-Posts in various liquid/powder mixing ratios were measured. Thereafter, the natural frequency values of the zinc phosphate cement-cemented posts were continuously detected during ultrasonic vibration. Moreover, both the natural frequency values and the dislodgement forces in response to ultrasonic vibrations were measured for the pretreated post samples. Results showed that the natural frequency values of the posts significantly decreased from 8.8 ± 0.8 to 5.0 ± 0.5 kHz (P < 0.05) before and after ultrasound treatment, respectively. The natural frequency values and the dislodgement forces of tested posts had a highly linear relationship (R² = 0.99, P < 0.05). These findings suggest that natural frequency is a variable for monitoring the stability status of zinc phosphate cement-cemented dental posts.

Hepatoprotection of Graptopetalum paraguayense E. Walther on CCl4-induced liver damage and inflammation.

AIM OF THIS STUDY: Graptopetalum paraguayense E. Walther, a vegetable consumed in Taiwan, has been used in folk medicine for protection against liver injury, although its actual efficacy remains uncertain. Therefore, we investigated the protective effects of Graptopetalum paraguayense E. Walther against carbon tetrachloride (CCl(4))-induced liver damage in rats. MATERIALS AND METHODS: Water extracts of Graptopetalum paraguayense E. Walther (WGP) were administered for 8 consecutive weeks to male Sprague-Dawley rats. And a dose-dependent manner in preventing liver damage was confirmed. Moreover, the major ingredient of WGP, gallic acid, was also orally administrated in the CCl(4)-induced rats. The hepatoprotective activity was assessed using various biochemical parameters such as antioxidant enzymes and histopathological studies. RESULTS: WGP ranging from 50 to 300 mg/kg bw administrations significantly lowered serum aspartate transaminase (AST) and alanine transaminase (ALT) levels, and inhibited malondialdehyde (MDA) generation in CCl(4)-treated rats. WGP increased cellular GSH level and antioxidant enzymes, including superoxide dismutase, glutathione reductase, and catalase. Serum tumor necrosis factor-alpha (TNF-α) was decreased in the group treated with CCl(4) plus WGP (150 and 300 mg/kg bw). Histopathological examination of livers showed that WGP reduced fatty degeneration, cytoplasmic vacuolization and necrosis in CCl(4)-treated rats. In contrary, 10mg/kg bw of gallic acid was administrated, this dose was related with WGP (300 mg/kg bw), and had significantly decreased the AST and ALT compared to the CCl(4)-treated group. Aforesaid results suggested that gallic acid from WGP offered antioxidative activity against CCl(4)-induced oxidative liver damage. CONCLUSIONS: Taken together, this study is the first time to suggest that Graptopetalum paraguayense E. Walther exerts hepatoprotection via promoting antioxidative and anti-inflammatory properties against CCl(4)-induced oxidative liver damage.

Effects of compressive residual stress on the morphologic changes of fibroblasts.

Recently, the term tensotaxis was proposed to describe the phenomenon that tensile stress or strain affects cell migration. Even so, less attention has been paid to the effects of compressive stress on cell behavior. In this study, by using an injection-molded method combined with photoelastic technology, we developed residual stress gradient-controlled poly-L-lactide discs. After culturing NIH-3T3 fibroblasts on the stress gradient substrate, the cell distributions for high- and low-stress regions were measured and compared. Our results showed that there were significantly more cells in the low-compressive stress region relative to their high-stress analogs (p < 0.05). In addition, NIH-3T3 fibroblasts in the low-compressive stress region expressed more abundant extensive filopodia. These findings provide greater insight into the interaction between cells and substrates, and could serve as a useful reference for connective tissue development and repair.