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woven bone [keywords]
- DEVELOPMENT AND CHARACTERIZATION OF NOVEL MEDICATED NANOFIBERS AGAINST PERIODONTITIS. [JOURNAL ARTICLE]
- Curr Drug Deliv 2014 Dec 5.
Periodontitis is an inflammatory disease of gums involving degeneration of periodontal ligaments, creation of periodontal pocket and resorption of alveolar bone, thus disrupting the support structure of teeth causing their loosening and finally removal. Since the disease is mainly confined to the periodontal pocket, so site specific drug delivery of an antibiotic is the best suitable option. This also eradicates the demerits of oral dosing like low drug concentration reaching the target site and the various systemic side effects. In the present work, an efficient and easy technique of electrospinning has been used to develop non-woven drug loaded and biodegradable nanofiber patch with inbuilt property of high surface area to volume ratio. Hyaluronic acid (HA) has been used specifically as the polymer since it possesses remarkable properties like providing an extracellular matrix supporting tissue regeneration, anti-inflammation and mucoadhesion. A blend of this natural polymer with another polymer (Polyvinyl alcohol) has been tried since HA alone cannot be electrospun efficiently as it shows very high viscosity at very low polymer concentration. The developed formulation presented controlled release behavior with good mucoadhesive strength. The in vivo studies confirmed the maintenance of minimum inhibitory concentration (MIC) over an extended period of time in addition to a significant anti-inflammatory effect. All these observations suggested that the above formulation form a stable intra periodontal pocket drug delivery system.
- Osseointegration of Ti-6Al-4V Alloy Implants with a Titanium Nitride Coating Produced by a PIRAC Nitriding Technique: A Long-Term Time Course Study in the Rat. [JOURNAL ARTICLE]
- Microsc Microanal 2014 Dec 8.:1-11.
This study examined bone tissue responses to Ti-6Al-4V alloy implants with a hard TiN coating applied by an original powder immersion reaction-assisted coating (PIRAC) nitriding method. Progression of implant fixation in the distal epiphysis and within the medullary cavity of the rat femur was evaluated between 3 days and 6 months postimplantation by scanning electron microscopy, oxytetracycline incorporation, and histochemistry. After 6 months, successful osseointegration was achieved in both epiphyseal and diaphyseal sites. Throughout, implant portions located within the epiphysis remained in close contact with bone trabeculae that gradually engulfed the implant forming a bone collar continuous with the trabecular network of the epiphysis. In the diaphysis, woven bone was first formed within the marrow cavity around the implant and later was replaced by a shell of compact bone around the implant. In general, higher osseointegration rates were measured for TiN-coated versus the uncoated implants, both in the epiphysis and in the diaphysis. In conclusion, our findings indicate an excellent long-term biocompatibility of TiN coatings applied by the PIRAC nitriding technique and superior osteoinductive ability in comparison with uncoated Ti-6Al-4V alloy. Such coatings can, therefore, be considered for improving the corrosion and wear resistance of titanium-based orthopedic implants.
- Benign osteoblastoma of maxilla: a case report emphasizing the histopathological differential diagnosis. [Journal Article]
- J Clin Diagn Res 2014 Oct; 8(10):ZD21-3.
Benign osteoblastoma is a rare bone tumour characterized histologically by production of woven bone spicules, which are bordered by prominent osteoblasts. It mainly affects male teenagers and young adults. A case of benign osteoblastoma of maxilla in a nineteen years old male is reported here. Also, histological comparison is made between benign osteoblastoma, aggressive osteoblastoma and osteosarcoma.
- Paleopathological Description and Diagnosis of Metastatic Carcinoma in an Early Bronze Age (4588+34 Cal. BP) Forager from the Cis-Baikal Region of Eastern Siberia. [Journal Article]
- PLoS One 2014; 9(12):e113919.
Extensive osteolytic and osteoblastic lesions were observed on the skeletal remains of an adult male excavated from an Early Bronze Age cemetery dated to 4556+32 years BP, located in the Cis-Baikal region of Siberia (Russian Federation). Lytic lesions ranged in size from several mm to over 60 mm in diameter and had irregular, moth-eaten borders. Many of these lesions destroyed trabecular bone, though a hollowed shell of cortical bone often remained observable. Radiographic analysis revealed numerous lytic lesions within trabecular bone that had not yet affected the cortex. Blastic lesions were identified as spiculated lines, bands, or nodules of mostly immature (woven) bone formed at irregular intervals. Anatomical elements with the greatest involvement included those of the axial skeleton (skull, vertebrae, sacrum, ribs, and sternum) as well as proximal appendicular elements (ossa coxae, proximal femora, clavicles, scapulae, and proximal humeri). Osteocoalescence of destructive foci was observed on the ilium and frontal bone, with the largest lesion found on the right ilium. Differential diagnoses include metastatic carcinoma, mycotic infections, tuberculosis, Langerhan's cell histiocytosis, and multiple myeloma. Based on lesion appearance and distribution, age and sex of the individual, as well as pathogen endemism, the most likely diagnostic option for this set of lesions is metastatic carcinoma. The age and sex of this individual and appearance of the lesions may reflect carcinoma of the lung or, possibly, prostate. This represents one of the earliest cases of metastatic carcinoma worldwide and the oldest case documented thus far from Northeast Asia.
- Effects of in vitro chondrogenic priming time of bone-marrow-derived mesenchymal stromal cells on in vivo endochondral bone formation. [JOURNAL ARTICLE]
- Acta Biomater 2014 Nov 20.
Recapitulation of endochondral ossification leads to a new concept of bone tissue engineering via a cartilage intermediate as an osteoinductive template. In this study, we aimed to investigate the influence of in vitro chondrogenic priming time for the creation of cartilage template on the in vivo endochondral bone formation both qualitatively and quantitatively. To this end, rat bone-marrow-derived mesenchymal stromal cells (MSCs) were seeded onto two scaffolds with distinguished features: a fibrous poly(lactic-co-glycolic acid)/poly(ε-caprolactone) electrospun scaffold (PLGA/PCL) and a porous hydroxyapatite/tricalcium phosphate composite (HA/TCP). The constructs were then chondrogenically differentiated for 2, 3 and 4weeks in vitro, followed by subcutaneous implantation in vivo for up to 8weeks. A longer chondrogenic priming time resulted in a significantly increased amount and homogeneous deposition of the cartilage matrix on both the PLGA/PCL and HA/TCP scaffolds in vitro. In vivo, all implanted constructs gave rise to endochondral bone formation, whereas the bone volume was not affected by the length of priming time. An unpolarized woven bone-like structure, with significant amounts of cartilage remaining, was generated in fibrous PLGA/PCL scaffolds, while porous HA/TCP scaffolds supported progressive lamellar-like bone formation with mature bone marrow development. These data suggest that, by utilizing a chondrogenically differentiated MSC-scaffold construct as cartilage template, 2weeks of in vitro priming time is sufficient to generate a substantial amount of vascularized endochondral bone in vivo. The structure of the bone depends on the chemical and structural cues provided by the scaffold design.
- miR-124 Negatively Regulates Osteogenic Differentiation and In Vivo Bone Formation of Mesenchymal Stem Cells. [JOURNAL ARTICLE]
- J Cell Biochem 2014 Nov 25.
MicroRNAs are novel key regulators of cellular differentiation. Dlx transcription factors play an important role in osteoblast differentiation, and Dlx5 and Dlx2 are known targets of miR-124. Therefore, in the present study, we investigated the regulatory effects of miR-124 on the osteogenic differentiation and in vivo bone formation of mesenchymal stem cells (MSCs). During osteogenic induction by BMP2, the expression levels of miR-124 were inversely correlated with those of osteogenic differentiation marker genes in human and mouse bone marrow-derived MSCs, MC3T3-E1 cells and C2C12 cells. The overexpression of a miR-124 mimic significantly decreased the expression levels of Dlx5, Dlx3 and Dlx2, whereas the silencing of miR-124 with hairpin inhibitors significantly increased the expression of these Dlx genes. Luciferase reporter assays demonstrated that miR-124 directly targets the 3'UTRs of Dlx3, Dlx5 and Dlx2. The overexpression of a miR-124 mimic suppressed the osteogenic marker gene expression levels, alkaline phosphatase activity and matrix mineralization, which were all significantly increased by the overexpression of a miR-124 inhibitor. When ectopic bone formation was induced by the subcutaneous transplantation of human bone marrow-derived MSCs in nude mice, MSCs overexpressing a miR-124 inhibitor significantly enhanced woven bone formation compared with control MSCs. However, MSCs overexpressing a miR-124 mimic exhibited increased adipocyte differentiation at the expense of ectopic bone formation. These results suggest that miR-124 is a negative regulator of osteogenic differentiation and in vivo bone formation and that the targeting of Dlx5, Dlx3 and Dlx2 genes partly contributes to this inhibitory effect exerted by miR-124. This article is protected by copyright. All rights reserved.
- Comparative assessment of the interfacial soft and hard tissues investing implants and natural teeth in the macaque mandible. [JOURNAL ARTICLE]
- Clin Oral Investig 2014 Nov 21.
The aim of this study was to conduct a comparative qualitative and quantitative assessment of the interfacial soft and hard tissues investing implants and natural teeth.The test sample consisted of six adult healthy male Macaca fascicularis with three-unit splinted crowns, each crown supported by an Ankylos screw-shaped titanium implant. These implants were placed in the mandibular premolar-second molar region, one side by an immediate-loading (IL) and the other by delayed-loading (DL) protocol. The animals were sacrificed after 3 months of functional loading. Another two monkeys with natural dentition served as controls. Nondecalcified sections were prepared for assessment of optical intensities (OI) under a confocal laser scanning microscope.In both the test (IL and DL) and control, the soft tissue complexes demonstrated a highly fluorescent keratinized layer and diminished cytoplasmic and enhanced membranous fluorescence in the remaining epithelium. Peri-implant mucosa was further characterized by an intense fluorescence at the junctional epithelium-implant interface and in the stromal mononuclear infiltrate. Connective tissue contact and periodontal ligament were weakly fluorescent. In hard tissues, a high fluorescence was observed in peri-implant woven bone and along the implant-bone interface. Mean OI was significantly higher in peri-implant woven bone than around teeth (P < 0.05). In the remaining soft and hard tissue complexes, no significant differences in mean OI between the test and control were observed (P > 0.05).Present findings suggest that peri-implant woven bone is highly mineralized, while the peri-implant and gingival mucosa share structural similarities.Optical intensities of interfacial tissues investing implants and teeth are related to their biological properties.
- Brown tumors of the femur and pelvis secondary to a parathyroid carcinoma: Report of one case. [Journal Article]
- Rev Med Chil 2014 Jul; 142(7):919-23.
Brown tumors result from excess osteoclast activity and consist of collections of osteoclasts intermixed with fibrous tissue and poorly mineralized woven bone. They are secondary to hyperparathyroidism (HPT). Their incidence is higher in primary than in secondary hyperparathyroidism. We report a 69 years-old male, admitted in a state of confusion, lethargy and bedridden, with a pathological fracture of the femur caused by a brown tumor. The laboratory examination revealed a hypercalcemia (8.85 mEq/L), with high levels of ionized Ca (5.48mEq/L), serum alkaline phosphatases (416 U/L) and serum parathormone (120 pg/mL). Ultrasound examination of the neck showed a large parathyroid tumor, probably corresponding to a carcinoma. A primary HPT was diagnosed. The patient was hydrated and high doses of diuretics and bisphosphonates were administered. After correction of serum calcium and neurologic symptoms, the patient was operated, performing an extensive resection of the tumor. The pathology report confirmed the diagnosis of parathyroid carcinoma.
- Preservation of a tooth related with central giant cell granuloma with non-invasive curettage: 7 years followed-up case report. [Journal Article]
- Oral Health Dent Manag 2014 Sep; 13(3):634-7.
Central Giant Cell Granuloma (CGCG) is defined by the World Health Organization as an intraosseous lesion consisting of cellular fibrous tissue containing multiple foci of hemorrhage, aggregations of multinucleated giant cells, and occasionally trabeculae of woven bone. An 8-year-old patient presented with painless swelling and bleeding in his upper right canine region was referred to our clinic. Incisional biopsy was confirmed that this was a CGCG. The patient was treated with non-invasive curettage and secondary intention healing. Seven-year follow-up of the patient revealed a complete resolution of the lesion and uneventful eruption of the permanent canine tooth. In this case report, a successful long-term outcome of the conservative treatment of the CGCG was presented.
- Novel EP4 receptor agonist-bisphosphonate conjugate drug (C1) promotes bone formation and improves vertebral mechanical properties in the ovariectomized rat model of postmenopausal bone loss. [JOURNAL ARTICLE]
- J Bone Miner Res 2014 Oct 4.
Current treatments for postmenopausal osteoporosis aim to either promote bone formation or inhibit bone resorption. The C1 conjugate drug represents a new treatment approach by chemically linking the anti-resorptive compound alendronate (ALN) with the anabolic agent prostanoid EP4 receptor agonist (EP4a) through a linker molecule (LK) to form a conjugate compound. This enables the bone-targeting ability of ALN to deliver EP4a to bone sites and mitigate the systemic side effects of EP4a, while also facilitating dual anti-resorptive and anabolic effects. In vivo hydrolysis is required to release the EP4a and ALN components for pharmacological activity. Our study investigated the in vivo efficacy of this drug in treating established bone loss using an ovariectomized (OVX) rat model of postmenopausal osteopenia. In a curative experiment, 3-month-old female Sprague-Dawley rats were OVX, allowed to lose bone for 7 weeks, then treated for 6 weeks. Treatment groups consisted of C1 conjugate at low and high doses, vehicle-treated OVX and sham, prostaglandin E2 (PGE2 ), and mixture of unconjugated ALN-LK and EP4a to assess the effect of conjugation. Results showed that weekly administration of C1 conjugate dose-dependently increased bone volume in trabecular bone, which partially or completely reversed OVX-induced bone loss in the lumbar vertebra and improved vertebral mechanical strength. The conjugate also dose-dependently stimulated endocortical woven bone formation and intracortical resorption in cortical bone, with high dose treatment increasing the mechanical strength but compromising the material properties. Conjugation between the EP4a and ALN-LK components was crucial to the drug's anabolic efficacy. To our knowledge, the C1 conjugate represents the first time that a combined therapy using an anabolic agent and the anti-resorptive compound ALN has shown significant anabolic effects which reversed established osteopenia. © 2014 American Society for Bone and Mineral Research.