Overexpression of programmed cell death ligand 1 reduces LPS-induced inflammatory cytokine upregulation and enhances osteo/odontogenic-differentiation of human dental pulp stem cells via upregulation of CCCTC-binding factor.

OBJECTIVE: The aim of this study was to explore the effect and mechanism of programmed cell death ligand 1 (PD-L1) in promoting the proliferation and osteo/odontogenic-differentiation of human dental pulp stem cells (hDPSCs) by mediating CCCTC-binding factor (CTCF) expression. DESIGN: The interaction between PD-L1 and CTCF was verified through co-immunoprecipitation. hDPSCs transfected with PD-L1 overexpression and CTCF knockdown vectors were treated with lipopolysaccharide or an osteogenic-inducing medium. Inflammatory cytokines and osteo/odontogenic-differentiation related genes were measured. Osteo/odontogenic-differentiation of hDPSCs was assessed using alkaline phosphatase (ALP) and alizarin red S staining. RESULTS: Overexpression of PD-L1 inhibited LPS-induced pro-inflammatory cytokine upregulation, cell proliferation, ALP activity, and calcium deposition in hDPSCs and elevated the expression of osteo/odontogenic-differentiation related genes; however, such expression patterns could be reversed by CTCF knockdown. Co-immunoprecipitation results confirmed the binding of PD-L1 to CTCF, indicating that PD-L1 overexpression in hDPSCs increases CTCF expression, thus inhibiting the inflammatory response and increasing osteo/odontogenic-differentiation of hDPSCs. CONCLUSION: PD-L1 overexpression in hDPSCs enhances the proliferation and osteo/odontogenic-differentiation of hDPSCs and inhibit the inflammatory response by upregulating CTCF expression.

Mechanical characteristics analysis of high dimensional vibration isolation systems based on high-static-low-dynamic stiffness technology.

Large floating raft vibration isolation systems (FRVISs) based on high-static-low-dynamic stiffness (HSLDS) technology offer excellent low frequency vibration isolation performance with broad application prospects. However, the design process for these complex high-dimensional coupled nonlinear systems remains poorly developed, particularly when applied for ocean-going vessels that experience rolling and pitching motions. The present work addresses this issue by establishing a six-degree-of-freedom HSLDS vibration isolation model for FRVISs composed of eight isolators, and the model is applied to fully analyze the swing stability and multidimensional vibration isolation performance of these systems. The influence of nonlinearity on the mechanical properties of the vibration isolators is analyzed more clearly by assuming that each vibration isolator realizes nonlinear HSLDS characteristics in the z direction and linear characteristics in the x and y directions. The results demonstrate that the swing displacement responses of the system are greatly reduced under weak nonlinearity, which reflects the high static stiffness and high static stability characteristics of an HSLDS system. The multidimensional vibration isolation performance of the system is evaluated according to the impacts of nonlinearity, the installation height Hz of the isolators, and the relative position Dr of the two middle isolators. The results of analysis demonstrate that applying a value of Hz = 0 produces the best vibration isolation performance overall under strong nonlinearity by avoiding unnecessary secondary peaks in the force transmission rate under harmonic mechanical excitation and ensuring a maximum high-frequency vibration isolation effect. However, applying a weak nonlinearity is better than a strong nonlinearity if Hz is not zero. In contrast, Dr has little effect on the vibration isolation effect of the raft in the x, y, and z directions. Therefore, an equidistant installation with Dr = 0.5 would be considered ideal from the standpoint of installation stability.

Mutations of the TGFBR2 gene in Chinese patients with Marfan-related syndrome.

PURPOSE: Transforming growth factor beta receptors II gene (TGFBR2) mutations associated with Marfan syndrome and Marfan-associated disorders have been investigated. However, such studies are limited in China. To obtain more information about TGFBR2 mutations, we analyzed 6 unrelated Chinese patients with Marfan-associated disorders and without ocular manifestation. METHODS: The genomic DNA from blood leukocytes of these 6 patients and their relatives was isolated, and the entire coding region of TGFBR2 was amplified using PCR. We determined the sequence of TGFBR2 with the ABI 3100 Genetic Analyzer. RESULTS: Three mutations were identified in TGFBR2. Two mutations were associated with Loeys-Dietz syndrome (LDS), which were distributed as following: one missense mutation R528C (caused by a 1582C > T substitution) and one polymorphism T315M (a rare SNP). The third mutation was a novel silent mutation associated with MFS2, which was K291K caused by an 873 C > T substitution. CONCLUSIONS: The TGFBR2 gene missense mutations are possibly causative mutations of Loeys-Dietz syndrome. This result suggests an increase in the mutation spectrum of Marfan-related disorders in China and possibly world-wide.

[Early surgical treatment for infants with large atrial septal defects or ventricular septal defects complicated by pneumonia: experience of 39 cases].

OBJECTIVE: This research reported the experience of early surgical treatment for infants with large atrial septal defects (ASD) or ventricular septal defects (VSD) complicated by pneumonia. METHODS: Between January 2003 and January 2008, 39 infants with large ASD or VSD complicated by pneumonia were admitted to the Second Xiangya Hospital. Thirty-six patients underwent surgical repair within 7-10 days after pneumonia had been controlled. Mean age was 5.4+/-3.4 months and mean weight was 4.7+/-1.6 kg in the 36 patients. Three patients received conservative treatment due to uncontrolled lung infections. RESULTS: Of the 36 patients, 33 had successful surgery and 3 (8.3%) died of serious low cardiac output (n=1) or respiratory failure due to congenital tracheostenosis (n=2). The 33 survivors showed normal growth and development in a 6 month-5 year follow-up. Of the 3 patients receiving conservative treatment, 1 died of cardiopulmonary failure and 2 were discharged after the symptoms had been improved. CONCLUSIONS: With increasing medical experience and technique, early surgical operation may be performed with good outcomes in infants with large ASD or VSD complicated by pneumonia.