Evaluation of Cytotoxicity and Biocompatibility of Ti2AlC in Rabbits

Background: The Titanium and its alloys are suitable for dental implant and medical applications. Biocompatibility of the materials is a major factor in determining the success of the implant and has a great impact on their rate of osseointegration. The aim of this study was to evaluate the biocompatibility and cytotoxicity of Ti2AlC in comparison to CPTi & Ti6Al7Nb in rabbits. Materials and Methods: 10 male New Zealand White rabbits, weighing (2-2.5 kg), aged (10-12 months) were used in this study. Cylindrical implants were prepared from the study materials (CPTi, Ti6Al7Nb and Ti2AlC) with (8mm) height and (3mm) diameter for the evaluation of tissue response and disc specimens were prepared with (6 mm) diameter and (2 mm) thickness for evaluation of cytotoxicity MTT test. A histological study was performed at 2 & 6 weeks post- surgical implant insertion. Results: Histological findings show that Ti2AlC has enhanced proliferation of osteo-progenitor cell and reported mature bone formation at 6 weeks. Moreover, Ti2AlC has recorded a higher percentage for viable cells by MTT test in comparison to CPTi and Ti6Al7Nb. Conclusion: The new Ti2AlC dental implant is considered biocompatible and has showed a better bone formation than the CPTi and Ti6Al7Nb materials at 2 & 6 weeks.

Heterotopic Ossification of the Inferior Vena Cava Wall: A Case Report and Literature Review

Masses of the inferior vena cava (IVC) are very diverse, most of which are thrombus and tumor thrombus, whereas heterotopic ossification of IVC has never been reported. Heterotopic ossification (HO) is the formation of mature lamellar bone outside normal bones and in soft tissues. Some researchers believe that HO is a manifestation of vascular calcification. Here we present a case of HO of the inferior vena cava (IVC) wall. A 68 year old female patient complaining hypertension and palpitation and diagnosed with a retroperitoneal mass was found to have a primary mass of the inferior vena cava wall during surgery. Histopathological examination after surgical resection revealed that the mass was mainly composed of mature bone tissues and hematopoietic tissues of bone marrow, there was no recurrence and the patient was symptom-free 15 months after the surgery. HO of the inferior vena cava wall is very rare, with large volume it can affect the circulation, and this case remind us that it can be cured by surgical resection.

Tongue Osseous Choristoma in an 11-Year-Old Female: A Case Report and Literature Review Focusing on Pediatric Cases

Osseous choristoma is an uncommon benign lesion characterized by the presence of ectopic mature bone within soft tissue. In most cases, these lesions occur on the dorsum of the tongue in patients in their third and fourth decades of life. This article describes a case of lingual osseous choristoma in a pediatric patient. An eleven-year-old girl with a lingual mass was referred to our hospital from a dental clinic. Total excisional biopsy and histological examination were performed, and osseous choristoma was diagnosed. The postoperative course was uneventful with no signs of recurrence during the 12 months after surgery. Moreover, a literature review focusing on pediatric cases with lingual osseous choristoma was performed to know the etiology, clinicopathological characteristics, and course of treatment of the lesion.

Impact of FasL Stimulation on Sclerostin Expression and Osteogenic Profile in IDG-SW3 Osteocytes

The Fas ligand (FasL) is known from programmed cell death, the immune system, and recently also from bone homeostasis. As such, Fas signalling is a potential target of anti-osteoporotic treatment based on the induction of osteoclastic cell death. Less attention has been paid to osteocytes, although they represent the majority of cells within the mature bone and are the key regulators. To determine the impact of FasL stimulation on osteocytes, differentiated IDG-SW3 cells were challenged by FasL, and their osteogenic expression profiles were evaluated by a pre-designed PCR array. Notably, the most downregulated gene was the one for sclerostin, which is the major marker of osteocytes and a negative regulator of bone formation. FasL stimulation also led to significant changes (over 10-fold) in the expression of other osteogenic markers: Gdf10, Gli1, Ihh, Mmp10, and Phex. To determine whether these alterations involved caspase-dependent or caspase-independent mechanisms, the IDG-SW3 cells were stimulated by FasL with and without a caspase inhibitor: Q-VD-OPh. The alterations were also detected in the samples treated by FasL along with Q-VD-OPh, pointing to the caspase-independent impact of FasL stimulation. These results contribute to an understanding of the recently emerging pleiotropic effects of Fas/FasL signalling and specify its functions in bone cells.

A rare case of osseous metaplasia in anaplastic thyroid cancer

Anaplastic thyroid cancer is the most advanced and aggressive thyroid cancer. It is very rare and isfound in less than 2% of patients with thyroid cancer. It most commonly occurs in people over theage of 60 years. It is usually diagnosed at later stages when the disease has already spread tosurrounding structures or has grown large enough to compress the trachea or esophagus causingpressure symptoms. The patient here, a 75-year-old female, presented with a large swelling in thefront of the neck in euthyroid status which was diagnosed as anaplastic thyroid cancer and wasmanaged surgically and the surgical specimen was sent for histopathological examination. Thepresence of osseous metaplasia with mature bone formation in anaplastic thyroid carcinoma is a rareentity and has been discussed in this case report.

Bilateral Diffuse Nodular Pulmonary Ossification Mimicking Metastatic Disease in a Patient with Fibrolamellar Hepatocellular Carcinoma

Pulmonary ossification (PO) is a rare finding, characterized by mature bone formation in the lung parenchyma. We report a 20-year-old female patient diagnosed with fibrolamellar hepatocellular carcinoma (FL-HCC) and bilateral diffuse nodular PO. The patient presented with a unifocal left liver mass and multiple bilateral pulmonary lesions, which were treated as metastatic disease. The patient received neoadjuvant chemotherapy, followed by left hepatectomy, and bilateral staged thoracotomies for clearance of the pulmonary disease. The histology of the pulmonary nodules demonstrated nodular type PO. We present the history, the course of treatment, imaging, and histologic findings of this rare disease process that could mimic metastatic pulmonary disease.

Tenascin-W: Discovery, Evolution, and Future Prospects

Of the four tenascins found in bony fish and tetrapods, tenascin-W is the least understood. It was first discovered in the zebrafish and later in mouse, where it was mistakenly named tenascin-N. Tenascin-W is expressed primarily in developing and mature bone, in a subset of stem cell niches, and in the stroma of many solid tumors. Phylogenetic studies show that it is the most recent tenascin to evolve, appearing first in bony fishes. Its expression in bone and the timing of its evolutionary appearance should direct future studies to its role in bone formation, in stem cell niches, and in the treatment and detection of cancer.

Expression of CD44 in previously grafted alveolar bone.

Objetive: To determine the expressions of the bone surface marker CD44 in samples of alveolar bone previously regenerated with allograft, xenograft, and mixed, using the technique of guided bone regeneration. Material and Methods: This exploratory study was approved by the institutional research and ethics committee. By means of intentional sampling and after obtaining informed consent for tissue donation, 20 samples of alveolar bone previously regenerated with guided bone regeneration therapy with particulate bone graft and membrane were taken during implant placement. The samples were stained with hematoxylin-eosin for histological analysis, and by immunohistochemistry for the detection of CD44. Results: Sections with hematoxylin-eosin showed bone tissue with the presence of osteoid matrix and mature bone matrix of usual appearance. Of the CD44+ samples, 80% were allograft and 20% xenograft. The samples with allograft-xenograft were negative. There were no differences in the intensity of CD44 expression between the positive samples. The marker was expressed in osteocytes, stromal cells, mononuclear infiltrate, and some histiocytes. Eighty percent of the CD44+ samples and 100% of the samples in which 60 or more cells were labelled corresponded to allografts (p=0.000). A total of 67% of the samples from the anterior sector, and 40% from the posterior sector were CD44+ (p=0.689). Conclusion: This study shows for the first time that guided bone regeneration using allografts is more efficient for the generation of mature bone determined by the expression of CD44, compared to the use of xenografts and mixed allograft-xenograft, regardless of the regenerated anatomical area.