A Calcifying Odontogenic Cyst With Compound Odontoma in the Maxillary Sinus: A Case Report in a Pediatric Patient.

Calcifying odontogenic cysts (COCs) exhibit a diverse clinical course, commonly developing between the second and third decades of life, displaying no gender predilection. A 15-year-old female without medical history was under observation for a mixed lesion in the maxilla associated with an impacted tooth. She presented to the emergency department with sudden onset and worsening swelling of the left midface. Radiographic findings in the panoramic radiograph and a CT scan revealed a well-circumscribed mixed lesion localized in the left maxilla, extending into the left maxillary sinus and reaching the orbital floor. After an intercurrent infection of the cyst, the patient was hospitalized, received intravenous antibiotics, and went for surgical intervention under general anesthesia. Lesions that combine histological characteristics of two or more odontogenic tumors or individual cysts in the same location are called hybrid odontogenic lesions. This type of lesion poses a challenge for both pathologists and surgeons, because of its controversial histogenesis and poorly understood clinical evolution. The most common of these lesions are COCs associated with odontoma. Our case represents an exceptionally rare entity among odontogenic cysts.

The role of hybrid chitosan membranes on scarring process following lumbar surgery: post-laminectomy experimental model.

OBJECTIVES: Post-operative scarring process on lumbar surgery is object of several studies mainly because of the epidural fibrosis formation. Hybrid chitosan have shown promising effect on fibrosis prevention. The aim of this study was to determine the influence of chitosan-silane membrane on the lumbar surgery scarring process. These membranes have improved mechanical strength which makes them suitable to maintain a predefined shape. METHODS: A two level lumbar laminectomy was performed in 14 New Zealand male rabbits. Laminectomy sites were randomly selected for biomaterial or control. Chitosan membranes were prepared and care was taken in order to make it adapted to the bone defect dimensions covering the totality of the defect including the bone margins. Histological analysis was performed by haematoxylin/eosin and by Masson's trichrome staining four weeks after laminectomy. RESULTS: Microscope observations revealed the presence of a well-organized regenerating tissue, integrated in the surrounding vertebral bone tissue with a regular and all-site interface on the chitosan sites, in clear contrast with the presence of a disorganized regenerating tissue with aspects consistent with the persistence of a chronic inflammatory condition, on control sites. DISCUSSION: The results of this study clearly demonstrated that hybrid chitosan had an organizing effect on post-operative scarring process. The presence of the hybrid chitosan membrane resulted on a well-organized tissue integrated in the surrounding vertebral bone tissue with signs of regenerative bone tissue in continuity with native bone. This can be a major feature on the dynamics of epidural fibrosis formation.

Challenges for nerve repair using chitosan-siloxane hybrid porous scaffolds.

The treatment of peripheral nerve injuries remains one of the greatest challenges of neurosurgery, as functional recover is rarely satisfactory in these patients. Recently, biodegradable nerve guides have shown great potential for enhancing nerve regeneration. A major advantage of these nerve guides is that no foreign material remains after the device has fulfilled its task, which spares a second surgical intervention. Recently, we studied peripheral nerve regeneration using chitosan-γ-glycidoxypropyltrimethoxysilane (chitosan-GPTMS) porous hybrid membranes. In our studies, these porous membranes significantly improved nerve fiber regeneration and functional recovery in rat models of axonotmetic and neurotmetic sciatic nerve injuries. In particular, the number of regenerated myelinated nerve fibers and myelin thickness were significantly higher in rat treated with chitosan porous hybrid membranes, whether or not they were used in combination with mesenchymal stem cells isolated from the Wharton's jelly of the umbilical cord. In this review, we describe our findings on the use of chitosan-GPTMS hybrids for nerve regeneration.

Maxilla osseus sequestre and oral exposure: effects of the treatment of multiple myeloma with bisphosphonates.

Multiple myeloma, the second most common haematopoietic cancer, represents a collection of plasma-cell neoplasms that invariably become fatal when self-renewing myeloma cells begin unrestrained proliferation. The major clinical manifestation of multiple myeloma is related to loss of bone through osteolysis. The bone disease can lead to pathologic fractures, spinal cord compression, hypercalcemia, and pain. It is also a major cause of morbidity and mortality in these patients. These patients frequently require radiation therapy, surgery and analgesic medications. Bisphosphonates are specific inhibitors of osteoclastic activity, and are currently used to prevent bone complications and to treat malignant hypercalcemia in patients with multiple myeloma, or bone metastases from breast and prostate cancers. Recent published reports have documented a possible link between treatment with intravenous bisphosphonates and osteonecrosis of the jaw. Bisphosphonates have been demonstrated to alter the normal bone microenvironment and appear to have direct effects on tumours as well. These changes may contribute to the development of osteonecrosis of the jaw in these patients, particularly after tooth extractions or other invasive dental procedures. Osteonecrosis of the mandible has been reported in 3 patients from Centro Hospitalar de Vila Nova de Gaia (CHVNG) with multiple myeloma treated for over 18 to 48 months with intravenous bisphosphonate zoledronate. It has been postulated that bisphosphonates may cause oral avascular bone necrosis due to antiangiogenic effect leading to disruption of osteoclast-mediated bone resorption. Although this report serves to alert clinicians about the potential complication of bone necrosis in patients receiving bisphosphonates therapy, many questions remain concerning the underlying pathogenesis of this process. In these 3 described clinical cases, surgical debridment without flap elevation, intensive antibiotherapy and zolendronate treatment arrest made possible the partial recovery of the patients. We purpose this type of clinical approach in patients suffering from multiple myeloma and bone osteonecrosis induced by bisphosphonate treatment. Research to determine the mechanism of this dental phenomenon is needed to fully validate and substantiated the possible link between bisphosphonates treatment of multiple myeloma or other cancer diseases with avascular osteonecrosis of the jaws. Until then, clinicians involved in the care of patients at risk should consider this possible complication.

Effect of zona pellucida removal on DNA methylation in early mouse embryos.

Removal of the zona pellucida is known to affect mouse development to term. Zygotes were recovered immediately after fertilization and their zona pellucida removed by exposure to pronase before culture and comparison with zona-intact embryos. The effect of removing the zona pellucida was assessed in terms of embryo development to blastocyst, DNA methylation, histone acetylation, and expression of three developmentally regulated genes. No significant differences were seen in percentage of embryos that developed to the blastocyst stage. However, zona-free embryos showed a significant reduction in the DNA methylation level at two-cell and four-cell stages, but no differences at pronuclear, morula, and blastocyst stages, as observed by immunofluorescence. Mechanical or enzymatic removal of the zona pellucida showed similar DNA methylation staining patterns at the two-cell stage. The time when the zona pellucida was removed appears to influence the levels of DNA methylation. When zona removal was delayed for 8 h, there was no difference in DNA methylation levels between zona-free and zona-intact two-cell embryos, indicating that the critical time is early on, between 1 and 8 h postfertilization. In contrast, when immunofluorescence analysis of histone acetylation was performed, no significant differences were seen between zona-free and zona-intact embryos at any of the developmental stage. Similarly, no differences were found regarding the onset of transcription of Dnmt1s, Nanog, and Fgf4 genes.

Ionic transport in tall columnar epithelial (TCE) cells obtained by nasal brushing from non-cystic fibrosis (CF) individuals.

Tall columnar epithelial (TCE) cells can be obtained by a non-invasive procedure through brushing the inferior turbinate and the adjacent lateral nasal wall. Here, we present results from the functional study of epithelial cells, thus obtained by using the patch-clamp technique. By patch-clamping the sub-apical region of TCE cells, we were able to identify at least three different groups of Cl- channels, namely: a) one with large conductance, rectifying, which was the most frequently found type of Cl- channel; b) a second type of small conductance, activated by cAMP and IBMX, in excised inside-out patches and voltage independent; c) a third type with a conductance around 25 pS, voltage independent, with a linear IV relationship, that could be observed in the excised inside-out configuration. The study of CFTR Cl- channel and its role in airway cell physiology has generally been conducted in cultured cells, most of which not polarized. This experimental work using freshly obtained TCE cells from the nasal epithelium, demonstrates that such cells may be one valid tool to study Cl- channels (most probably ORCC and CFTR Cl- channels) as a model for the lower respiratory epithelium.