Study on the therapeutic effects and prognosis evaluation of non-invasive ventilation in patients with chronic obstructive pulmonary disease with lung cancer.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a prevalent respiratory complication among the elderly, and its severity can escalate to respiratory failure as the disease progresses. OBJECTIVE: To evaluate the application value of non-invasive ventilation in the clinical treatment of patients with COPD and lung cancer. This study assesses its therapeutic effects and its impact on patients' quality of life (QoL) as measured by the Functional Assessment of Cancer Therapy-Lung (FACT-L) scale. METHODS: A retrospective analysis was conducted on clinical data from 102 patients with COPD and lung cancer. Patients were divided into two groups: the control group (n= 48), who received conventional treatment, and the observation group (n= 54), who received non-invasive positive pressure ventilation (NIPPV) in addition to conventional treatment. Relevant indicators of curative effect, including blood gas indices, incidence of dyspnoea, improvements in mental health and appetite, and FACT-L QoL scores, were analysed at 2 weeks, 1 month, and 6 months post-treatment. RESULTS: At 2 weeks post-treatment, the observation group who had used NIPPV showed significant improvements in blood gas indices, dyspnoea, mental state and self-care ability compared with the control group (p< 0.05). At 1 month, these benefits persisted and included improved maintenance of body weight (p< 0.05). By 6 months, the observation group had a lower incidence of pulmonary encephalopathy (p< 0.05), and QoL, as measured by the FACT-L scale, improved significantly in the observation group but declined in the control group (p< 0.05). CONCLUSION: NIPPV demonstrates significant efficacy in treating COPD patients with lung cancer, particularly in enhancing curative effects and improving patients' QoL.

Influencing factors of negative conversion time of nucleic acid detection in 228 patients infected with Omicron variant of SARS-CoV-2 in Shanghai / 中国热带医学

@#Abstract: Objective To analyze and compare the effects of different clinical characteristics on the negative conversion time of nucleic acid detection after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant infection, and to provide a scientific basis for the isolation and treatment of coronavirus disease 2019 (COVID-19). Methods　The epidemiological and clinical data of 228 mild SARS-CoV-2 Omicron variant infected patients diagnosed in Shanghai were retrospectively collected from April 27, 2022 to June 8, 2022 in Wujiaochang designated Hospital, Yangpu District, Shanghai. The negative conversion time of nucleic acid detection was used as the outcome variable, and the patients were divided into A (≤18 days) and B (>18 days). Univariate and multivariate logistic regression analysis were used to analyze the influencing factors of the negative conversion time of nucleic acid detection. Results　The mean nucleic acid conversion time of 228 patients was (18.7±12.1) d, with the median time of 18 (2-46) d. Among them, 120 patients in group A had an average nucleic acid conversion time of (13.2±2.0) d, and 108 cases in group B had an average nucleic acid conversion time of (20.8±1.3) d. Univariate analysis showed that there were no statistically significant differences in the effects of hypertension, coronary heart disease, diabetes, hypokalemia, malignant tumors, neuropsychiatric diseases, chronic digestive diseases on the negative nucleic acid conversion time (P>0.05); however, there were significant differences in the effects of combined cerebrovascular disease, leukopenia, chronic respiratory system diseases and vaccination on the negative nucleic acid conversion time (P<0.05). Further multivariate logistic regression analysis revealed that the combination of chronic respiratory diseases and non-vaccination were significant risk factors for prolongation of negative nucleic acid conversion time (P<0.05). Conclusions The results of this study show that gender, age and whether hypertension, coronary heart disease, diabetes mellitus, hypokalemia, malignant tumor, neuropsychiatric disease and chronic digestive disease have no significant effect on the nucleic acid conversion time, whereas chronic respiratory disease and no vaccination are significantly correlated with the prolongation of nucleic acid conversion time in SARS-CoV-2 Omicron-infected patients.

Concentrated growth factor promotes proliferation, osteogenic differentiation, and angiogenic potential of rabbit periosteum-derived cells in vitro.

OBJECTIVE: The aim of this research is to investigate the effects of concentrated growth factor (CGF) on the proliferation, osteogenic differentiation, and angiogenic potential of rabbit periosteum-derived cells (PDCs) in vitro. METHODS: PDCs were isolated from the femoral and tibial periosteum of rabbits and cultured with or without CGF membranes or CGF conditioned media. Scanning electron microscopy (SEM) was used for the structural characterization. Cell Counting Kit-8 assay was used to measure cell proliferation. Alkaline phosphatase (ALP) activity of PDCs was also measured. Immunohistochemistry was used to detect the expression of CD34. Enzyme-linked immunosorbent assay (ELISA), quantitative real-time PCR (qPCR), and Western blot were used to evaluate the secretion and expression levels of osteogenic differentiation markers (bone morphogenetic protein-2, type I collagen, osteocalcin) and angiogenesis markers (vascular endothelial growth factor, basic fibroblast growth factor) in supernatants and PDCs at days 3, 7, 14, and 21. RESULTS: The SEM analysis showed a dense three-dimensional fibrin network in CGF, and CGF membranes were covered by PDCs with elongated or polygonal morphological features. Compared with the control group, CGF significantly promoted the proliferation of PDCs during the experimental period (p < 0.05). Immunohistochemistry revealed that PDCs were dispersedly distributed among the CGF substrates, and CD34-positive cells were also present. Moreover, CGF significantly increased the ALP activity and upregulated the expression and secretion of osteogenic differentiation and angiogenesis markers in PDCs at days 3, 7, 14, and 21 (p < 0.05). CONCLUSION: CGF can increase the proliferation and promote the osteogenic differentiation and angiogenic potential of PDCs in vitro. These results indicate that CGF can be used as a new therapeutic means for biotechnological and clinical applications.

MRI compatibility of several early transition metal based alloys and its influencing factors.

Magnetic resonance imaging (MRI) compatibility of three early transition metal (ETM) based alloys was assessed in vitro with agarose gel as a phantom, including Zr-20Nb, near-equiatomic (TiZrNbTa)90 Mo10 and Nb-60Ta-2Zr, together with pure tantalum and L605 Co-Cr alloy for comparison. The artifact extent in the MR image was quantitatively characterized according to the maximum area of 2D images and the total volume in reconstructed 3D images with a series of slices under acquisition by fast spin echo (FSE) sequence and gradient echo (GRE) sequence. It was indicated that the artifacts extent of L605 Co-Cr alloy with a higher magnetic susceptibility (χv ) was approximately 3-fold greater than that of the ETM-based alloys with χv in the range of 160-250 ppm. In the ETM group, the MRI compatibility of the materials can be ranked in a sequence of Zr-20Nb, pure tantalum, (TiZrNbTa)90 Mo10 and Nb-60Ta-2Zr. In addition, using a rabbit cadaver with the implanted tube specimens as a model for ex vivo assessment, it was confirmed that the artifact severity of Nb-60Ta-2Zr alloy is significantly reduced in comparison with the L605 alloy. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 377-385, 2018.

Rab5a is overexpressed in oral cancer and promotes invasion through ERK/MMP signaling.

Ras-related protein Rab-5A (Rab5a) has been identified to be overexpressed in several types of human cancer. However, its clinical significance and biological roles in oral cancer remain unclear. In the present study, the protein expression of Rab5a was examined in 79 cases of oral squamous cell carcinoma samples using immunohistochemistry. It was demonstrated that Rab5a protein was upregulated in 49.3% (39/79) of cancer samples. Small interfering RNA knockdown was performed on Detroit 562 cells with high endogenous expression. Rab5a transfection was performed in FaDu cells with low endogenous levels. Rab5a depletion was revealed to inhibit cell growth, invasion and colony formation while its overexpression facilitated cell growth, invasion, and colony formation. In addition, Rab5a facilitated cell cycle progression and cell migration. It was also demonstrated that Rab5a depletion downregulated and its overexpression upregulated the expression levels of various cell cycle­associated proteins, and matrix metalloproteinase­2 (MMP­2). Furthermore, Rab5a positively regulated the extracellular signal­regulated kinase (ERK) signaling pathway and promoted epithelial­mesenchymal transition (EMT). ERK inhibitor PD98059 partially inhibited the role of Rab5a on MMP­2, cyclin D1, cell proliferation and invasion. The results of the present study suggest that Rab5a is overexpressed in oral cancer tissue samples and promotes the malignant phenotype through EMT and the ERK/MMP­2 signaling pathway.

[Comparison of adaptation of crowns of different lithium disilicate glass-ceramic].

OBJECTIVE: To evaluate the adaptation of different lithium disilicate glass-ceramic crown and whether different fabrication processes affect the adaptation of crowns. METHODS: Thirty epoxy dies crowns were divided into 3 groups. They were cemented to domestic lithium disilicate glass-ceramic crowns in Group A, to IPS e.max CAD crowns in Group B and to IPS e.max Press crowns in Group C respectively. All crowns were cut by cutting machine. A confocal laser scanning microscope was used to measure the gap between crown tissue surface and die. RESULTS: There were significant differences in the three groups of measurement points(P<0.05). Within the groups, specimens in group A showed in the lowest marginal fit([46.8±9.1] µm). Those in group B showed the lowest shoulder suitability([59.3±7.9] µm), axial plane([50.5±3.6] µm) and occlusal surface([87.6±11.6 µm]. Those in group C demonstrated the lowest axial plane angle[(84.4±10.1) µm]. In addition to the axial plane angle, the CAD/CAM system exhibited good accuracy of fit. CONCLUSIONS: The three groups of lithium disilicate glass-ceramic crowns appeared to have clinically acceptable fit.

The fluoride coated AZ31B magnesium alloy improves corrosion resistance and stimulates bone formation in rabbit model.

This study aimed to evaluate the effect of fluorine coated Mg alloy and clarify its mechanism in bone formation. We implanted the fluorine coated AZ31B Mg alloy screw (group F) in rabbit mandibular and femur in vivo. Untreated AZ31B Mg alloy screw (group A) and titanium screw (group T) were used as control. Then, scanning electron microscopy, the spectral energy distribution analysis, hard and decalcified bone tissues staining were performed. Immunohistochemistry was employed to examine the protein expressions of bone morphogenetic protein 2 (BMP-2) and collagen type I in the vicinity of the implant. Compared with the group A, the degradation of the alloy was reduced, the rates of Mg corrosion and Mg ion release were slowed down, and the depositions of calcium and phosphate increased in the group F in the early stage of implantation. Histological results showed that fluorine coated Mg alloy had well osteogenic activity and biocompatibility. Moreover, fluoride coating obviously up-regulated the expressions of collagen type I and BMP-2. This study confirmed that the fluorine coating might improve the corrosion resistance of AZ31B Mg alloy and promote bone formation by up-regulated the expressions of collagen type I and BMP-2.

Different study conditions between dental students in China and Japan.

BACKGROUND: The purpose of this study was to compare the study conditions of dental students towards dental education in China and Japan. METHODS: 60 students from the Stomatology School of China Medical University and 51 students from the Dental Faculty of Kyushu University, Japan, participated in this study. Information was derived from a self-answered questionnaire consisting of 10 items. RESULTS: More Japanese students (60%) compared to Chinese students (28%) were satisfied with their lives in dental school. For the main reason of discontent, 23.5% of the Japanese students attributed to busy study and lacking of spare time, while 38.3% of the Chinese students indicated small campus lacking of infrastructure. CONCLUSIONS: Both students of two countries think they were in big pressure. The main stressor of Japanese students was the examination, but that of Chinese students was anxiety of their future and obtains employment. The main source of tuition and maintenance was family in the both countries, but more Japanese students (25.5%) were dependent on scholarship compared with Chinese students (3.3%). CLINICAL IMPLICATIONS: The findings from this study enhance our understanding of study conditions among dental students and help to define strategies to improve student management in both Japan and China.

Career choice and future plan of Chinese 8-year stomatology medical doctor program students.

BACKGROUND: This elite education reform that commenced in 2001 aims to improve the quality of Chinese dentists. It is expected to be one of the biggest drivers that lead dental education of China to a new stage. The authors identified and analyzed the perspectives of Chinese 8-year stomatology medical doctor (SMD) program students toward their career choice and future plan. METHODS: The data from a self-administered questionnaire (4 items regarding career choice and 6 items about future plan), administered to 87 8-year SMD program students from the School of Stomatology, Peking University, Beijing, China, were used. The authors performed a comparison of the students of different sexes and home locations using the Chi-square test. RESULTS: Of the students, 34.5% indicated interpersonal motives as the reason to choose the 8-year SMD program, and only 52.9% thought that they had made good choices. The top three popular careers were those of prosthodontists (20.7%), oral surgeons (14.9%), and orthodontists (13.8%). The majority of students preferred first-tier cities (85.7%) and university hospitals (71.3%). CONCLUSION: In China, most 8-year S.M.D students would like to work as clinical dentists of university hospitals in first-tier cities. The top three career choices of graduates would be prosthodontists, oral surgeons, and orthodontists.

Association between implant apex and sinus floor in posterior maxilla dental implantation: A three-dimensional finite element analysis.

The aim of the present study was to evaluate the effect of the association between the implant apex and the sinus floor in posterior maxilla dental implantation by means of three-dimensional (3D) finite element (FE) analysis. Ten 3D FE models of a posterior maxillary region with a sinus membrane and different heights of alveolar ridge with different thicknesses of sinus floor cortical bone were constructed according to anatomical data of the sinus area. Six models were constructed with the same thickness of crestal cortical bone and a 1-mm thick sinus floor cortical bone, but differing heights of alveolar ridge (between 10 and 14 mm). The four models of the second group were similar (11-mm-high alveolar ridge and 1-mm-thick crestal cortical bone) but with a changing thickness of sinus floor cortical bone (between 0.5 and 2.0 mm). The standard implant model based on the Nobel Biocare® implant system was created by computer-aided design (CAD) software and assembled into the models. The materials were assumed to be isotropic and linearly elastic. An inclined force of 129 N was applied. The maximum von Mises stress, stress distribution, implant displacement and resonance frequencies were calculated using CAD software. The von Mises stress was concentrated on the surface of the crestal cortical bone around the implant neck with the exception of that for the bicortical implantation. For immediate loading, when the implant apex broke into or through the sinus cortical bone, the maximum displacements of the implant, particularly at the implant apex, were smaller than those in the other groups. With increasing depth of the implant apex in the sinus floor cortical bone, the maximum displacements decreased and the implant axial resonance frequencies presented a linear upward tendency, but buccolingual resonance frequencies were hardly affected. This FE study on the association between implant apex and sinus floor showed that having the implant apex in contact with, piercing or breaking through the sinus floor cortical bone benefited the implant stability, particularly for immediate loading.

Comparing the influence of crestal cortical bone and sinus floor cortical bone in posterior maxilla bi-cortical dental implantation: a three-dimensional finite element analysis.

OBJECTIVE: This study aimed to compare the influence of alveolar ridge cortical bone and sinus floor cortical bone in sinus areabi-cortical dental implantation by means of 3D finite element analysis. MATERIALS AND METHODS: Three-dimensional finite element (FE) models in a posterior maxillary region with sinus membrane and the same height of alveolar ridge of 10 mm were generated according to the anatomical data of the sinus area. They were either with fixed thickness of crestal cortical bone and variable thickness of sinus floor cortical bone or vice versa. Ten models were assumed to be under immediate loading or conventional loading. The standard implant model based on the Nobel Biocare implant system was created via computer-aided design software. All materials were assumed to be isotropic and linearly elastic. An inclined force of 129 N was applied. RESULTS: Von Mises stress mainly concentrated on the surface of crestal cortical bone around the implant neck. For all the models, both the axial and buccolingual resonance frequencies of conventional loading were higher than those of immediate loading; however, the difference is less than 5%. CONCLUSION: The results showed that bi-cortical implant in sinus area increased the stability of the implant, especially for immediately loading implantation. The thickness of both crestal cortical bone and sinus floor cortical bone influenced implant micromotion and stress distribution; however, crestal cortical bone may be more important than sinus floor cortical bone.

Maxillary Sinus Augmentation without Grafting Material with Simultaneous Implant Installation: A Three-Dimensional Finite Element Analysis.

PURPOSE: The study aims to provide a theoretical guidance of postmaxillary implant in the augmented sinus without grafting materials by establishing a three-dimensional model of this new implant restorative technique, evaluating failure risk of sinus augmentation without grafting materials of different alveolar ridge heights, and analyzing stress distribution of different healing stage. MATERIALS AND METHODS: Seventeen three-dimensional finite element models of a posterior maxillary region with sinus mucosa and different elevation heights were constructed according to anatomical data of sinus area, and the standard implant model based on Nobel Biocare implant system were created via computer-aided design software. All materials were assumed to be isotropic and linearly elastic. Axial force of 150 N was applied. The von Mises stress, stress distribution, and implant displacement were calculated with software. RESULTS: With the height of the alveolar ridge reducing, the maximum von Mises stress of tissues and the displacement of the implant are on the rise, especially when the height of the bone is less than 7 mm. When the height decreased to 4 mm, the data may be doubled. After the stiff callus stage, the stress and displacement were close to the control model. CONCLUSION: For maxillary sinus augmentation without grafting material implant technique, the stress of different tissues and the displacement of the implant were not increased much when the height of alveolar ridge is more than 7 mm. But if the alveolar bone height is less than 4 mm, this implant technique is not suggested. Immediately loading is not suggested and the loading opportunity should be after the stiff callus stage at least to improve the success rate.

MRI-compatible Nb-60Ta-2Zr alloy used for vascular stents: haemocompatibility and its correlation with protein adsorption.

Nb-60Ta-2Zr is a newly developed MRI-compatible alloy used for vascular stents. In this work, its haemocompatibility was investigated, including platelet adhesion (lactate dehydrogenase activity), platelet activation (P-selectin expression), coagulation and haemolysis. For comparison, parallel assessments for these factors were performed for the niobium, tantalum, 316L stainless steel (316L SS) and L605 Co-Cr alloy (L605). In addition, albumin and fibrinogen were selected to examine the correlation of protein adsorption with platelet adhesion and metal surface properties. The propensity for platelet adhesion and activation on the Nb-60Ta-2Zr alloy was at nearly the same level as that for Nb and Ta but was slightly less than those of 316L SS and L605. The mitigated platelet adhesion and activation of the Nb-60Ta-2Zr alloy is associated with its decreased adsorption of fibrinogen. The Nb-60Ta-2Zr alloy has a longer clotting time and exhibits significantly superior thromboresistance than 316L SS and L605. Moreover, the haemolysis rate of the Nb-60Ta-2Zr alloy satisfies the bio-safety requirement of the ISO 10993-4 standard. The favourable haemocompatiblity of the Nb-60Ta-2Zr alloy provides evidence of its good biocompatibility and of its suitability as a candidate stent material.

The responses of endothelial cells to Zr6 1Ti 2Cu25Al12 metallic glass in vitro and in vivo.

The goal of this study was to evaluate the biocompatibility of newly developed Zr61Ti2Cu25Al12 metallic glass (denoted ZT1) and its parallel material, commercially pure titanium (CP-Ti), as dental implants. To this end, we evaluated their cytotoxicity in vitro using human umbilical vein endothelial cells (HUVECs) and in vivo by performing an oral mucosa irritation test in hamsters. Specifically, cytotoxicity was determined in HUVECs by evaluating their cell morphology using scanning electron microscopy (SEM) and their cell viability using CCK-8 assays. Moreover, we examined the mRNA levels of vascular endothelial growth factor and von Willebrand factor by quantitative PCR (qPCR). In the early stages of proliferation and differentiation, no differences were observed between HUVECs inoculated on ZT1 compared to those on CP-Ti. However, in the later stages of proliferation and differentiation, the HUVECs inoculated on ZT1 were significantly better than the cells cultured on CP-Ti. In the oral mucosa irritation test, we sutured sample discs into the cheek pouch of hamsters. After 2, 3, and 4weeks, we harvested the corresponding mucosal tissues, stained them with hematoxylin and eosin, obtained blood samples for biochemical analysis, and finally, observed the topography of the sample discs by SEM. Immunohistochemistry and hematology analyses showed no differences in the biocompatibility of ZT1 and CP-Ti, and neither of these compounds caused irritation of the mucosa. In addition, SEM images showed that no pitting occurred on the sample discs. Together, these data indicate that ZT1 may be a good candidate for dental implants and should be further studied.

Career choice and future design of dental students in China and Japan.

The purpose of this study was to compare career choice and future plans of dental students in China and Japan. Information was derived from a self-answered questionnaire. Significant differences were detected for eight items between the two countries. Regarding motivation towards career choice, 41% of Japanese students indicated positive motives related to helping others, achieving self-worth and health-care related interests, whereas Chinese students indicated that their choice was mainly for financial and prestige reasons, and for 32% of them, dentistry was a passive choice. More Chinese dental students (74%) wanted further education compared with Japanese students (22%). The majority of Japanese students (56.9%) planned to work as general dentists. Conversely, Chinese students were more likely to specialise (50%). More than 50% of Japanese students wanted to work in dental offices, but the majority of Chinese students (65%) preferred university hospital. We found it is strange that nearly one-fourth of the Chinese students did not want to be a clinical dentist mainly because of the poor health-care environment. This study provides a description of the perspectives of Japanese and Chinese dental students and enables a better understanding of career choices and future course design issues.

Comparison of attitudes towards dental education among dental students in Japan and China.

The aim of this study was to identify and compare the attitudes of dental students towards dental education in Japan and China. Fifty-four dental students from the Stomatology School of China Medical University and 51 dental students from the Dental Faculty of Kyushu University, Japan, participated in this study. Information was derived from a self-answered questionnaire consisting of 11 items. Significant differences in the responses of the participants from the two countries were detected for 10 of the questionnaire items (P < 0.05). Nearly three-quarters of the Japanese students were satisfied with the teaching faculties of their schools, while only a quarter of the Chinese students indicated satisfaction. A total of 69% of Chinese students thought that learning a foreign language wasted too much time compared with none of the Japanese students. A student-oriented teaching mode was not well accepted by either of the groups, and 62% of Chinese students and 53% of Japanese students wanted to increase the duration of the clinical practice stage of education. The findings from this study enhance our understanding of differences and/or similarities among dental students in the two nations. This information may help to define strategies to improve the quality of dental education, and especially exchange programmes of international students.

[Effect of different denture cleaning methods on roughness in resin denture base].

OBJECTIVE: To determine the effect of different denture cleaning methods on surface roughness in resin denture base. METHODS: We established 20 wafer samples of fuser base resin (14 mm×14 mm×3 mm), and then randomly divided them into 4 groups: group A was the control group, which were placed in water, while group B, C and D were the experimental groups, whose cleaning methods were toothbrush and water, toothbrush and toothpaste, denture cleaning tablets, respectively. Each procedure in group B and C lasted for 3 seconds, but group D lasted 5 min and repeated for 1080 times. We cleaned twice a day to simulate the method of cleaning dentures. Surface roughness was checked after different procedures by laser scanning confocal microscopy. RESULTS: Significant difference on surface roughness was found between group B, C and A (P<0.05), while no significant difference in the surface roughness between group A and D (P>0.05). CONCLUSION: Significant surface roughness alterations have been observed in toothbrush and toothpaste group, but no change has been found in denture cleaning tablets group, which does not produce scratches on the surface of resin denture base.

Efficacy of cold light bleaching using different bleaching times and their effects on human enamel.

This study investigated the efficacy of cold light bleaching using different bleaching times and the effects thereof on tooth enamel. Before and after bleaching, stained tooth specimens were subjected to visual and instrumental colorimetric assessments using Vita Shade Guide and spectrophotometric shade matching. Enamel surface alterations were examined using scanning electron microscopy (SEM) to analyze surface morphology, surface microhardness (SMH) measurement to determine changes in mechanical properties, and X-ray diffraction (XRD) to characterize post-bleaching enamel composition. Cold light bleaching successfully improved tooth color, with optimal efficacy when bleaching time was beyond 10 min. Significant differences in surface morphology were observed among the different bleaching times, but no significant differences were observed for enamel composition and surface microhardness among the different bleaching times. Results of this study revealed an association between the bleaching time of cold light bleaching and its whitening efficacy. Together with the results on enamel surface changes, this study provided positive evidence to support cold light bleaching as an in-office bleaching treatment.

Activation of the ERK1/2 signaling pathway during the osteogenic differentiation of mesenchymal stem cells cultured on substrates modified with various chemical groups.

The current study examined the influence of culture substrates modified with the functional groups -OH, -COOH, -NH2, and -CH3 using SAMs technology, in conjunction with TAAB control, on the osteogenic differentiation of rabbit BMSCs. The CCK-8 assay revealed that BMSCs exhibited substrate-dependent cell viability. The cells plated on -NH2- and -OH-modified substrates were well spread and homogeneous, but those on the -COOH- and -CH3-modified substrates showed more rounded phenotype. The mRNA expression of BMSCs revealed that -NH2-modified substrate promoted the mRNA expression and osteogenic differentiation of the BMSCs. The contribution of ERK1/2 signaling pathway to the osteogenic differentiation of BMSCs cultured on the -NH2-modified substrate was investigated in vitro. The -NH2-modified substrate promoted the expression of integrins; the activation of FAK and ERK1/2. Inhibition of ERK1/2 activation by PD98059, a specific inhibitor of the ERK signaling pathway, blocked ERK1/2 activation in a dose-dependent manner, as revealed for expression of Cbf α -1 and ALP. Blockade of ERK1/2 phosphorylation in BMSCs by PD98059 suppressed osteogenic differentiation on chemical surfaces. These findings indicate a potential role for ERK in the osteogenic differentiation of BMSCs on surfaces modified by specific chemical functional groups, indicating that the microenvironment affects the differentiation of BMSCs. This observation has important implications for bone tissue engineering.

Effects of the surface characteristics of nanoporous titanium oxide films on Ti-24Nb-4Zr-8Sn alloy on the initial adhesion of osteoblast-like MG-63 cells.

The aim of the present study was to investigate the effects of the surface characteristics of nanoporous titanium oxide films, formed by anodization on Ti-24Nb-4Zr-8Sn (Ti2448) alloy, on the early adhesion of osteoblast-like MG-63 cells. Nanoporous titanium oxide films with two different pore sizes (30 and 90 nm) were formed by anodization in NH4F solution on Ti2448 alloy. The surface roughness of the nanoporous titanium oxide films was determined using a Surftest Formtracer and field emission scanning electron microscopy (FESEM). Cell viability was evaluated at different time points using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. To investigate the regulatory mechanisms involved in the focal adhesion of osteoblasts to Ti2448 alloy, we quantified the expression levels of integrin ß1 and paxillin mRNAs on the nanoporous titanium oxide films during early osteoblast adhesion using real-time RT-PCR. Samples with a 30-nm nanoporous film exhibited a greater number of overlapping microporous structures with microprojections compared with the 90-nm nanoporous film samples. The MTT assay indicated that cell viability on the 30-nm nanoporous surface following 24 and 48 h of cell culture was higher than those observed on the unanodized control and 90-nm nanoporous surfaces. Integrin ß1 mRNA expression levels on the 30-nm nanoporous surface following cell culture for 48 h were also significantly higher compared with those on the unanodized control and 90-nm nanoporous surfaces. The results demonstrated that a 30-nm nanoporous titanium oxide film on Ti2448 alloy may provide the optimum bioactive implant surface for the initial adhesion of osteoblasts.