Expression of human thromboxane synthase using a baculovirus system

AbstractHuman thromboxane (TX) synthase (EC 5.3.99.5) was produced by the baculovirus expression system using cDNA encoding human TX synthase [(1991) Biochem. Biophys. Res. Commun. 78, 1479-1484]. A recombinant baculovirus TXS7 was expressed in Spodoptera frugiperda Sf9 insect cells. The expressed protein was recognized by monoclonal antibody, Kon 7 raised against human TX synthase [(1990) Blood 76, 80-85]. The recombinant TX synthase catalyzed the conversion of prostaglandin (PG) H2 to TXA2 and 12-hydroxy-heptadecatrienoic acid (HHT). Both conversions of PGH2 to TXA2 and HHT by the expressed TX synthase were completely inhibited by a specific TX synthase inhibitor, OKY-046 (5 μM)

Expression of human thromboxane synthase using a baculovirus system

AbstractHuman thromboxane (TX) synthase (EC 5.3.99.5) was produced by the baculovirus expression system using cDNA encoding human TX synthase [(1991) Biochem. Biophys. Res. Commun. 78, 1479-1484]. A recombinant baculovirus TXS7 was expressed in Spodoptera frugiperda Sf9 insect cells. The expressed protein was recognized by monoclonal antibody, Kon 7 raised against human TX synthase [(1990) Blood 76, 80-85]. The recombinant TX synthase catalyzed the conversion of prostaglandin (PG) H2 to TXA2 and 12-hydroxy-heptadecatrienoic acid (HHT). Both conversions of PGH2 to TXA2 and HHT by the expressed TX synthase were completely inhibited by a specific TX synthase inhibitor, OKY-046 (5 μM)

Minimization of dental implant diameter and length according to bone quality determined by finite element analysis and optimized calculation

Purpose: The purpose of this study was to investigate the influences of bone quality and implant size on the maximum equivalent elastic strain (MES) in peri-implant bone using finite element (FE) analysis, and to minimize implant size via optimized calculation based on MES. Methods: Three-dimensional FE models consisting of a mandible and a titanium implant with a superstructure were constructed and applied a vertical load or an oblique load of 60 N. We investigated the effects of four variables: the thickness of the cortical bone (C), Young's modulus of the trabecular bone (T), and the diameter (D) and length (L) of the implant. According to the variables determined using Latin hypercube sampling, 500 FE models were constructed and analyzed under each of the loads following the construction of response surfaces with the MES as a response value. D and L were minimized by optimized calculation with the MES limited to the physiological limit with reference to the mechanostat theory. Results: The MES was significantly influenced by D more than L, and could be restricted to the physiological limit unless both C and T were small. Larger MES than physiological limit was observed around the bottom of implants. Conclusions: From the viewpoint of the mechanostat theory, we calculated minimum size of implants according to the bone quality. However, the results should be verified with more detailed FE models made using CT data, animal studies and clinical prognoses. (C) 2016 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved

Influence of changes in denture-base fit and connecting rigidity on the load distribution of abutment teeth and the displacement of abutment teeth and denture base in mandibular distal-extension removable partial dentures.

The purpose of this study was to clarify the influence of denture-base fit and retainer design on the distribution of stress on abutment teeth, and the displacement of abutment teeth and the denture base. A mandibular model with a simulated periodontal ligament and mucosa was fabricated to simulate a partially edentulous case with the right first molar and second molar missing. The edentulous area was made flat to eliminate the influence of residual ridge forms. Two types of removable partial dentures with different direct retainers: 1, a cone crown telescope （CCT）; and 2, a modified circumferential clasp with a distal guide plate, a buccal retentive arm and a lingual enlarged bracing arm （MCC）, with an embrasure clasp as an indirect retainer, were designed. The following conditions of the denture-base conformity with the simulated mucosa were established: completely suitable（ CS）, mesial half unsuitable（ M－）, distal half unsuitable（ D－）, buccal half unsuitable （B－）, lingual half unsuitable （L－）, and completely unsuitable （CU）. A 200μm clearance area was made between the denture base and simulated mucosa on these unsuitable parts. The stresses at the apical, buccal and distal portions, the distal displacement of abutment teeth and the subsidence of the denture base were investigated. Both the stress on and the displacement of abutment teeth for the partially unsuitable denture base were larger than those for the completely suitable denture bases for the CCT-retained denture. The distal stress and distal displacement of abutment teeth for the completely unsuitable denture base were larger than for the completely suitable denture base with the MCC-retained denture. The buccal stress distribution and the distal displacement of the abutment teeth with the CCT-retained denture were significantly larger than those with the MCC-retained denture under all conditions. When the denture base was completely unsuitable or the distal part was unsuitable, the subsidence of the denture base with the MCC-retained denture was larger than that with the CCT-retained denture. These results showed that the denture base fit influenced the stress and displacement of the abutment teeth for the CCT-retained denture more than that for the MCC-retained denture, and the subsidence of the denture base of the MCC-retained denture was the same as that of the CCT-retained denture when the unsuitable parts of the denture base were only mesial and buccal. Thus, the MCC-retained denture does not cause overloading of abutment teeth and the residual ridge even if the fitness of the denture base decreases

Thin films of single-walled carbon nanotubes promote human osteoblastic cells (Saos-2) proliferation in low serum concentrations

One strategy used for the regeneration of bone is the development of cell culture substrates and scaffolds that can control osteoblast proliferation and differentiation. In recent investigations, carbon nanotubes (CNTs) have been utilized as scaffolds for osteoblastic cell cultures; however, there are only a few reports describing the proliferation of osteoblastic cells on thin CNT films; in particular, the effects of serum concentration on cell proliferation has not been studied. In the present study, we prepared culture dishes with homogeneous thin or thick films of non-modified CNTs and examined the effect of serum concentrations on human osteoblastic cells (Saos-2) proliferation in these culture dishes. We demonstrated that the ratio of cell proliferation was strongly affected by the concentration of serum. Interestingly, single-walled carbon nanotube (SWNT) thin films were found to be the most effective substrate for the proliferation of Saos-2 cells in low concentrations of serum. Thus, thin SWNT films may be used as an effective biomaterial for the culture of Saos-2 cells in low serum concentrations

Maintenance of hemiround colonies and undifferentiated state of mouse induced pluripotent stem cells on carbon nanotube-coated dishes

Induced pluripotent stem (iPS) cells have attracted　worldwide interest. However, there　have been only a few studies investigating effective culture　substrates for feeder-free culturing for the　maintenance of iPS cells. In this study, we cultured mouse iPS cells under feeder-free conditions on carbon nanotube (CNT)-coated dishes and then evaluated the colony morphology and differentiation state of the cells on the dishes. After 5 d of cultivation in a medium containing 15% fetal bovine serum (FBS) and leukemia inhibitory factor (LIF), the colonies on thick films of multi-walled CNTs (MWCNTs) were observed to be hemiround; further, the cells expressed early undifferentiation markers. On the other hand, the colonies on a cell culture polystyrene dish and a collagen-coated polystyrene dish showed indistinct outline and spread well, and most spreading cells only weakly expressed early undifferentiation markers. These results indicate that the thick films of MWCNTs could maintain hemiround colonies and undifferentiated state of mouse iPS cells cultured under feeder-free conditions

Significance of mandibular molar replacement with a dental implant: a theoretical study with nonlinear finite element analysis

Abstract Background Dental implants are frequently applied to unilateral defects in the mandible. However, implant placement in the molar region of the mandible can be difficult due to anatomical structure. The aim of this study was to evaluate the distribution of occlusal force in a mandibular shortened dental arch (SDA) with implants. Methods Three-dimensional finite element (FE) models of the mandible with varying numbers of teeth and implants were constructed. Models Im6 and Im67 contained one and two implants in the defect of the left molar region, respectively. Models Im456 and Im4567 contained three and four implants in the defect of the left premolar and molar regions, respectively. Model MT67 contained a defect in the molar region with no implant placed. Model MT7 represented natural dentition without a left second molar, as a control. Modification of the condition of occlusal contacts assuming the intercuspal position was performed before analysis under load 400 N; therefore, the load condition as total force on the occlusal surface was 400 N. FE analyses were subsequently performed under load conditions of loads 100, 200, and 800 N. The distribution of reaction forces on the occlusal surface and the mandibular condyle was investigated. Results Force distribution in models Im67 and Im4567 appeared to be symmetrical under all load conditions. Occlusal force distribution in models Im6 and Im456 was similar to that in model MT7. However, the occlusal force at the second premolars on the defect side in those models was larger under loads 100 and 200 N. Conversely, the occlusal force on the first molars was much larger than that in model MT7 under load 800 N. Conclusions Within the limitations of this theoretical study, we demonstrated that restoration with the same number of implants as missing teeth will show almost symmetric occlusal force distribution, and it will produce less biomechanically stress for a unilateral defect of the mandible. However, if restoration of a missing second molar with an implant is impossible or difficult, then an SDA with implants may also be acceptable except for individuals with severe bruxism

Adhesion of Osteoblast-like Cells (Saos-2) on Micro-/Submicro-Patterned Apatite Scaffolds Fabricated with Apatite Cement Paste by Micro-Molding

In the present study, we developed patterned apatites with grooves, pillars, and holes by micro-molding. The effects of the patterns on adhesion of the human osteoblastic cell line Saos-2 were investigated. The patterned apatites were fabricated with apatite cement paste using the mi-cro-molding method. The number of attached cells and ratio of cell spreading were estimated by a cell adhesion assay using Saos-2. The resulting patterns of grooves, holes, and pillars at the mi-cro-/submicro-level were easily transferred using the corresponding mold. Saos-2 cells were well orientated on the grooves and filopodia were radially elongated on pillars. The number of attached cells on the patterned apatite was higher than that on the planar apatite. Interestingly, the tendency of increasing of ratios of spreading cells was similar to that of decreasing of water contact angle on apatite pillars. These results show that the adhesion of Saos-2 cells was affected by the type and size of the apatite patterns

Effect of Protein Adsorption on Alignment of Human Gingival Fibroblasts on Grooved Composite Resin

Groove patterns on the surface of implants act as an effective barrier to the apical migration of epithelial attachment, after which the grooves facilitate gingival fibroblast attachment. Cell alignment on grooves is largely influenced by the adsorbed protein type. However, cell attachment and cell alignment properties of micro/nano-grooved dental composite resins using osteoblasts and fibroblasts have not been investigated. Further, the effect of saliva-related protein adsorption has not investigated. In this study, we prepared composite resins with grooves that were 2 μm, 1 μm, and 500 nm wide and estimated the effect of pre-coating of some proteins, mainly mucin, on attachment and alignment of human gingival fibroblasts(HGF). In the cell attachment assay on mucin-coated grooves, the number of attached cells on mucin-coated planar or grooved composite resins was lower compared to that on both composite resins without pre-coating of mucin. Interestingly, the number of attached cells on grooves pre-coated with mucin was 5.7-fold higher than those on planar pre-coated with mucin. Grooves at the micro/nano level may act as a hook for floating cells during the cell attachment assay. Furthermore, the degree of cell alignment was strongly dependent on the pre-coating protein types. The cells were radially spread or round-shaped, but not have sufficient alignment on non-, mucin-, and albumin-coated grooves. Although the cells were attached on the grooves, they were not aligned along the direction of grooves. The cells on fetal bovine serum- or fibronectin-coated grooves exhibited good alignment in the groove direction, particularly on fibronectin-coated grooves. Thus, our patterning method creates an effective seal between soft tissue and dental materials to protect against microorganism invasion