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Patients suffering from bone defects are often treated with autologous bone transplants, but this therapy can cause many complications. New approaches are therefore needed to improve treatment for bone defects, and stem cell therapy presents an exciting alternative approach. Although extensive evidence from basic studies using stem cells has been reported, few clinical applications using stem cells for bone tissue engineering have been developed. We investigated whether injectable tissue-engineered bone (TEB) composed of mesenchymal stem cells (MSCs) and platelet-rich plasma was able to regenerate functional bone in alveolar deficiencies. We performed these studies in animals and subsequently carried out large-scale clinical studies in patients with long-term follow-up; these showed good bone formation using minimally invasive MSC transplantation. All patients exhibited significantly improved bone volume with no side effects. Newly formed bone areas at 3 months were significantly increased over the preoperation baseline ( p < .001) and reached levels equivalent to that of native bone. No significant bone resorption occurred during long-term follow-up. Injectable TEB restored masticatory function in patients. This novel clinical approach represents an effective therapeutic utilization of bone tissue engineering. S TEM C ELLS 2013;31:572-580 [ABSTRACT FROM AUTHOR]

Abstract: Objective: The aim of the present study is to investigate the involvement of immunocompetent cells, pro-inflammatory cytokines and HSP, to evaluate a change of periodontal ligament during the initial stage of orthodontic tooth movement. Design: In the present study, we investigated the distributional density of immunocompetent cells, the localisation of cytokines, and the expression levels of their mRNA in the periodontal ligament during the initial stage of orthodontic tooth movement, using immunohistochemistry and real-time PCR. Results: Orthodontic tooth movement led to significant recruitment of OX6+ cells and ED1+ cells in the rat PDL. Double-immunofluorescence staining showed that some ED1+ cells expressed pro-inflammatory factors of IL-1β and TNF-α in the PDL during orthodontic tooth movement. Real-time PCR analysis revealed that the expression levels of IL-1β (Il1b) and TNF-α (Tnf) mRNA gradually increased following its decrease after 1h of orthodontic tooth movement. These findings suggest that ED1+ cells are involved in the expression of TNF-α and IL-1β and the subsequent regulation of bone resorption on pressure side. HSP27 (Hspb1) mRNA levels were significantly increased as compared with the control at 1h of the initial stage of treatment. Conclusion: ED1+ cells involved in the expression of TNF-α and IL-1β may play an important role in the initial reaction of the PDL and in the induction of the osteoclastic bone resorption during orthodontic tooth movement. [Copyright &y& Elsevier]

β-tricalcium phosphate (β-TCP) granules are commonly used materials in dentistry or orthopedic surgery. However, further improvements are required to raise the operability and bone-forming ability of β-TCP granules in a clinical setting. Recently, we developed epigallocatechin gallate (EGCG)-modified gelatin sponges as a novel biomaterial for bone regeneration. However, there is no study on using the above material for preparing hydrogel incorporating β-TCP granules. Here, we demonstrate that vacuum heating treatment induced thermal cross-linking in gelatin sponges modified with EGCG and incorporating β-TCP granules (vhEc-GS-β) so that the hydrogels prepared from vhEc-GS-β showed high stability, β-TCP granule retention, operability, and cytocompatibility. Additionally, microcomputed tomography morphometry revealed that the hydrogels from vhEc-GS-β had significantly higher bone-forming ability than β-TCP alone. Tartrate-resistant acid phosphatase staining demonstrated that the number of osteoclasts increased at three weeks in defects treated with the hydrogels from vhEc-GS-β compared with that around β-TCP alone. The overall results indicate that thermal cross-linking treatment for the preparation of sponges (precursor of hydrogels) can be a promising process to enhance the bone-forming ability. This insight should provide a basis for the development of novel materials with good operativity and bone-forming ability for bone regenerative medicine. [ABSTRACT FROM AUTHOR]

An antral pseudocyst (AP) is a common well-defined 'dome-shaped' faintly radiopaque lesion of the maxillary sinus, and usually does not require treatment in asymptomatic patients. However, when sinus floor augmentation is required to increase bone volume for implant installation, the elevation of the sinus mucosa might drive the AP against the ostium. This might cause its obstruction and, as possible consequence, sinusitis. The purpose of this study was to investigate the clinical and tomographic conditions of APs to identify a predictable cyst removal that might allow a safety sinus floor augmentation. A total of 52 maxillary sinuses in 46 patients (mean age 55.1 years) presenting AP were examined by cone beam computed tomographies (CBCTs). A two-stage approach was applied. At the first surgery, the cystic lesions were further inspected by an endoscope through the antrostomy, and histopathological diagnosis of the removed tissues was carried out. After the confirmation of decrease of the swelling of sinus membrane by CBCT, the sinus floor augmentation was performed, at least four months after cyst removal. The color and transparency of the 86 cystic lesions were classified into 4 types. The whitish transparent cysts were 34 (39.5%), the yellowish transparent cysts were 18 (20.9%), the dark purple transparent cysts were 8 (9.3%) and the milky-white opaque cysts were 26 (30.2%). The contents of the 60 (69.8%) transparent cysts were serous fluid, but those of milky-white cysts were composed of viscous or elastic soft tissues, and the aspiration of the contents was unsuccessful. The analysis of the preoperative CBCT did not provide certainty on the contents of the cystic lesions. All cystic lesions were diagnosed as AP, and an infection was identified in one AP, presenting marked infiltration of the inflammatory cells. Considering the difficulties of performing a correct diagnosis of the AP content by a CBCT analysis, the risk of failure of the surgery that creates severe afflictions to the patients, and the necessity of a histological evaluation of the cyst, a two-stage surgery appeared to be the most reliable procedure. [ABSTRACT FROM AUTHOR]

We investigate the physical origins of the Balmer decrement anomalies in GS-NDG-9422 and RXCJ2248-ID galaxies at z ∼ 6 whose H α /H β values are significantly smaller than 2.7, the latter of which also shows anomalous H γ /H β and H δ /H β values beyond the errors. Because the anomalous Balmer decrements are not reproduced under the Case B recombination, we explore the nebulae with optical depths smaller and larger than the Case B recombination by physical modeling. We find two cases quantitatively explaining the anomalies: (1) density-bounded nebulae that are opaque only up to around Ly γ –Ly8 transitions and (2) ionization-bounded nebulae partly/fully surrounded by optically thick excited H i clouds. The case of (1) produces more H β photons via Ly γ absorption in the nebulae, requiring fine tuning in optical depth values, while this case helps ionizing photon escape for cosmic reionization. The case of (2) needs the optically thick excited H i clouds with N 2 ≃ 1012−1013 cm−2, where N 2 is the column density of the hydrogen atom with the principal quantum number of n = 2. Interestingly, the high N 2 values qualitatively agree with the recent claims for GS-NDG-9422 with the strong nebular continuum requiring a number of 2 s -state electrons and for RXCJ2248-ID with the dense ionized regions likely coexisting with the optically thick clouds. While the physical origin of the optically thick excited H i clouds is unclear, these results may suggest gas clouds with excessive collisional excitation caused by an amount of accretion and supernovae in the high- z galaxies. [ABSTRACT FROM AUTHOR]