Osteoconductivity of hydrothermally synthesized beta-tricalcium phosphate composed of rod-shaped particles under mechanical unloading

Spherical beta-tricalcium phosphate (β-TCP) granules synthesized using a unique dropping slurry method expressed good osteoconductivity with prominent bone apposition and bioresorbability when implanted into the rat femur (Gonda et al, Key Eng. Mater. 361-363:1013-1016, 2008). The spherical β-TCP granules were implanted into the bone defect created in the distal end of the right femur of each 8-week-old female Wistar rat. To analyze performance of the spherical β-TCP granules as bone substitute in the bone with reduction in osteogenic potential, the right sciatic neurectomy was performed after implantation and the right hind limb was kept unloaded for 2 weeks before euthanization. Four weeks after implantation, some spherical β-TCP granules with resorption in part were surrounded by newly formed bone. Eight and 12 weeks after implantation, most of the residual β-TCP granules were embedded in newly formed bone, and total volume of the implant and newly formed bone was more than the other portions of the bone or the bone of control animals. Osteoclast activity in the implanted area was also higher than the other portions of the bone or the bone of control animals. Replacement of the intraosseous residual β-TCP granules for bone progressed at 12 weeks after implantation compared to those at 8 weeks after implantation. These data suggested that the spherical β-TCP granules stimulated osteogenesis and osteoclast activity of the unloaded bone

Stimulatory effect of hydrothermally synthesized biodegradable hydroxyapatite granules on osteogenesis and direct association with osteoclasts.

Calcium-deficient hydroxyapatite (HA) granules with a unique spherical shape were prepared using an applied hydrothermal method. Spherical stoichiometric HA granules were also prepared by normal sintering and both granules were used for implantation into rat tibiae to compare the biological responses to each implant. Twelve and 24 weeks after implantation, the volume of calcium-deficient HA granules was significantly less than that of stoichiometric HA granules, and the biodegradability of calcium-deficient HA granules was confirmed. The larger number of osteoclasts, larger osteoblast surface and larger bone volume in the implanted area of calcium-deficient HA than those of stoichiometric HA suggested that osteoclastic resorption of calcium-deficient HA affected osteogenesis in that area. To analyze the direct contribution of osteoclasts to osteogenesis, C2C12 multipotent myoblastic cells, which have the potential to differentiate into osteoblasts in the presence of bone morphogenetic protein 2, were cultured with supernatants of osteoclasts cultured on calcium-deficient HA, stoichiometric HA, beta-tricalcium phosphate disks or plastic dishes, or bone marrow macrophages cultured on plastic dishes. Supernatants of osteoclasts but not bone marrow macrophages stimulated the expression of Runx2 and osteocalcin in C2C12 cells in concert with bone morphogenetic protein 2. The expression of alkaline phosphatase was stimulated with supernatants of osteoclasts cultured on ceramic disks. These results suggested that osteoclasts produced certain soluble factors which stimulated osteoblastic differentiation and they were thought to be associated with the induction of a larger osteoblast surface and bone volume in the animals implanted with calcium-deficient HA granules

Scoliosis in Shprintzen–Goldberg Syndrome

We report a case of scoliosis in a 12-year-old girl with Shprintzen–Goldberg syndrome. She was diagnosed with Shprintzen–Goldberg syndrome at birth. She was hospitalized for a surgical treatment because scoliosis gradually progressed. Preoperative X-ray confirmed 80° symptomatic scoliosis in T10–L5. Posterior correction and fusion were performed, and postoperative X-ray showed a correction to 43°in T10-L5. Limited subcutaneous tissues and fragile bones must be considered when selecting the appropriate surgical method. Accurate placement of a screw into thin pedicle is essential to obtain sufficient correction and fusion. The use of a navigation system is recommended

Stimulation of Osteogenesis in Bone Defects Implanted with Biodegradable Hydroxyapatite Composed of Rod-Shaped Particles under Mechanical Unloading

The aim of thisSstudy was totevaluatertheninfluence of mechanical unloading on the repair of bone defects with implantation of biodegradable bone substitutes. Spherical granules of biodegradable hydroxyapatite composed of rod-shaped particles (RHA) or beta-tricalcium phosphate composed of rod-shaped particles (RTCP) were implanted into a bone defect created in the distal end of the right femur of 8-week-old Wistar rats. Two, 6, 10, and 22 weeks after implantation, part of the sciatic nerve in the thigh was resected and exposed to mechanical unloading for 2 weeks. Then, 4, 8, 12 and 24 weeks after implantation, repair of the bone defect was analyzed. As a control, the bone defect without implantation of ceramic granules was also analyzed. Both RHA and RTCP tended to be reduced, but the reduction was not obvious during the experimental period. At 12 and 24 weeks after implantation, the amount of newly formed bone in the animal implanted with RHA was significantly greater than that at 4 weeks after implantation, but that in the animal implanted with RTCP or without implantation was not significantly different. The number of osteoclasts in the region implanted with RHA was significantly larger than that of the region implanted with RTCP or without implantation at 12 and 24 weeks. The activities of alkaline phosphatase in osteoblasts and tartrate-resistant acid phosphatase in osteoclasts were remarkably increased in the bone defects with implantation compared with those in the bone defects without implantation. These results suggested that RHA stimulated osteogenesis and osteoclastogenesis even after 2 weeks of mechanical unloading, and that RHA could be expected to improve the repair of bone defects in patients under the condition of skeletal unloading

Behavior of β-tricalcium phosphate granules composed of rod-shaped particles in the rat tibia

Porous spherical granules of β-tricalcium phosphate (β3-TCP) composed of rod-shaped particles were prepared viaa hydrothermal route. The biological significance ofimplantation of the spherical β-TCP granules for healing of bone defects was analyzed by implantation into 2 mm diameter and 3 mm deep defects created intibiae of 9-week-oldWistar rats. Implantation of spherical β-TCP contributed to regeneration of bone tissue. At 2 and 4 weeks after implantation, numerous alkaline phosphatase-positive cells appeared around the implant and newly formed bone. At 8 weeks after implantation, residualimplants were mostly embedded in bone tissue. Without implantation, bone defects healed with a much lower amount of bone. In addition, bone marrow adipocytes were considerably fewer intibiae with implants compared to tibiae without implants at 4 and 8 weeks after the operation. These data suggested that implanted granules worked as scaffolds to maintainalkaline phosphatase-positive cells and also resulted in less fatty change of bone marrow

Two Cases of Rhegmatogenous Retinal Detachment Associated with Asteroid Hyalosis

Background: To report two cases of rhegmatogenous retinal detachment (RRD) associated with asteroid hyalosis (AH). Case Presentation: Two patients presented with RRD originating from a flap tear. Case 1 involved a 62-year-old male who was found to have bullous RRD in his left eye originating from a flap tear. During vitreous surgery, a thick vitreous cortex was found to have strongly adhered to the entire retinal surface, from the center to the periphery. A bimanual method was then used in conjunction with the vitrectomy to create an artificial posterior vitreous detachment. After surgery, the retina was successfully reattached, and his corrected visual acuity (VA) improved. Case 2 involved a 70-year-old male who was found to have localized RRD in his left eye originating from a flap tear. During vitreous surgery, a thick vitreous cortex was found to have strongly adhered to the entire retinal surface. After surgery, the retina was successfully reattached, and his corrected VA improved. Conclusions: RRD associated with AH presents with stronger vitreoretinal adhesion compared to typical RRD, thus requiring a more complicated surgical technique to properly treat the patient

Efficacy and safety of plasma exchange for Kawasaki disease with coronary artery dilatation

Abstract Background The treatment of Kawasaki disease is controversial when intravenous immunoglobulin therapy fails, although it typically relies on combinations of prednisolone, infliximab, cyclosporine, and plasma exchange therapy. The goal of the treatment is no longer merely to reduce mortality but also to decrease the sequelae of coronary artery lesions, which are the most common and potentially life-threatening complications. Recently, plasma exchange therapy has been used to treat intravenous immunoglobulin-unresponsive Kawasaki disease with coronary artery lesions. When performed before coronary artery dilatation, the outcomes for plasma exchange are known to be excellent; however, when dilatation is already present, sequelae persist. Methods Between December 2006 and April 2015, we treated ten patients with Kawasaki disease complicated by coronary artery lesions that received plasma exchange because intravenous immunoglobulin therapy had proven to be ineffective. Here, we retrospectively review the efficacy and safety of plasma exchange therapy in such unresponsive cases against coronary artery lesions in patients with Kawasaki disease when plasma exchange performed after coronary artery dilatation. Results In nine of the ten patients (90.0%), the body temperature was confirmed to be < 37.5 °C at an average of 2.7 ± 1.4 days after starting plasma exchange. Serum C-reactive protein levels decreased significantly from 9.9 ± 4.9 mg/dL before exchange to 1.9 ± 2.9 mg/dL after exchange (P < 0.05). One year after plasma exchange treatment, the coronary artery lesions had regressed to within normal limits in six of the ten patients. Although lesions remained in three patients, all three of these patients were asymptomatic. In addition, there were no stenosis of the coronary artery in nine of the ten patients. One patient died due to a ruptured giant coronary aneurysm 1 day after starting plasma exchange. Conclusions In conclusion, plasma exchange may be effective in not only regressing coronary artery lesions but also preventing sequelae in patients with Kawasaki disease when plasma exchange is performed after coronary artery dilatation