Patient-derived xenografts of a case of ameloblastic fibrodentinoma.

OBJECTIVES: The establishment of animal models of xenotransplantation can contribute to the elucidation of the molecular pathogenesis of ameloblastic fibrodentinomas (AFD) and it also provides an opportunity for drug tests. We aimed to evaluate the possibility of AFD tumour growth in a patient-derived xenograft (PDX) model. In addition, we characterized the human tumour and the PDXs. MATERIALS AND METHODS: A sample of a recurrent AFD was obtained and two fragments were contralaterally implanted subcutaneously in an 8-week old female NUDE mouse. After 250 days, the PDXs were removed and submitted to histopathological and molecular analysis. Immunohistochemical reactions for Ki67 and the phosphorylated form of ERK1/2 were carried out in both, PDXs and human tumour, and the presence of BRAFV600E was assessed. RESULTS: From day 135 onwards, the PDXs presented a growth peak and remained stable until day 250. Histopathologically, the PDXs presented the same features of the patient's tumour. Tumour cells exhibited Ki67 and pERK1/2 immunoexpression in the patient's tumour and PDX. The AFD was wild-type for BRAFV600E. CONCLUSION: The PDX model recapitulated well the human tumour after a long implantation time, representing a possible model to study the AFD and other odontogenic tumours pathobiology.

Dental management for patients undergoing heart valve surgery.

This study sought to review current guidelines and the most optimal dental management for patients undergoing cardiac valve surgery.

Hemorrhagic complications in individuals with liver disease submitted to minor oral surgery.

Individuals with chronic liver disease (CLD) have an increased risk of bleeding from thrombocytopenia and changes in hemostasis. The aim of this study was to evaluate the frequency of and the factors associated with the occurrence of bleeding in CLD patients who underwent dental surgical procedures. This was a retrospective study whose data were collected in a hospital dentistry service between 2010 and 2016. The patients were referred from the gastroenterology and liver transplantation services of a university hospital for dental treatment. The study followed the STROBE guidelines. Among the 71 surgical procedures performed, there were 17 (24%) perioperative and postoperative bleeding episodes, 14 of which were in pretransplant patients and 11 received blood transfusion before dental surgery. Individuals with a previous history of bleeding (PR = 2.67, CI = 1.07-6.67, P  = 0.035) and those with a platelet count before surgery 50 × 10 9 /l or less (PR = 7.48, CI = 1.70-32.86, P  = 0.008) had a higher prevalence of perioperative and postoperative bleeding episodes than their peers without a previous history of bleeding, and those with platelet count greater than 50 × 10 9 /l. The approach to individuals with CLD is complex and represents a challenge to the clinician. A careful anamnesis combined with laboratory screening of coagulation disorders appears to be useful to identify individuals at a major risk of bleeding. Studies identifying the predisposing factors of bleeding in CLD patients support well tolerated protocols for oral surgery in this group.