EVALUATION OF HARMONIC MOTION ELASTOGRAPHY AND ACOUSTO-­OPTIC IMAGING FOR MONITORING LESION FORMATION BY HIGH INTENSITY FOCUSED ULTRASOUND

Malignant or benign tumors may be ablated with high‐intensity focused ultrasound (HIFU). This technique, known as focused ultrasound surgery (FUS), has been actively investigated for decades, but slow to be implemented and difficult to control due to lack of real‐time feedback during ablation. Two methods of imaging and monitoring HIFU lesions during formation were implemented simultaneously, in order to investigate the efficacy of each and to increase confidence in the detection of the lesion. The first, Acousto‐Optic Imaging (AOI) detects the increasing optical absorption and scattering in the lesion. The intensity of a diffuse optical field in illuminated tissue is mapped at the spatial resolution of an ultrasound focal spot, using the acousto‐optic effect. The second, Harmonic Motion Imaging (HMI), detects the changing stiffness in the lesion. The HIFU beam is modulated to force oscillatory motion in the tissue, and the amplitude of this motion, measured by ultrasound pulse‐echo techniques, is influenced by the stiffness. Experiments were performed on store‐bought chicken breast and freshly slaughtered bovine liver. The AOI results correlated with the onset and relative size of forming lesions much better than prior knowledge of the HIFU power and duration. For HMI, a significant artifact was discovered due to acoustic nonlinearity. The artifact was mitigated by adjusting the phase of the HIFU and imaging pulses. A more detailed model of the HMI process than previously published was made using finite element analysis. The model showed that the amplitude of harmonic motion was primarily affected by increases in acoustic attenuation and stiffness as the lesion formed and the interaction of these effects was complex and often counteracted each other. Further biological variability in tissue properties meant that changes in motion were masked by sample‐to‐sample variation. The HMI experiments predicted lesion formation in only about a quarter of the lesions made. In simultaneous AOI/HMI experiments it appeared that AOI was a more robust method for lesion detection.

Le cancer épithélial des ovaires à cellules claires et de type mucineux exprime un niveau élevé de HYAL-1 : corrélation inverse avec l’expression des récepteurs d’estrogène et de progestérone

Le cancer épithélial des ovaires (CEO) est classifié en sous types histopathologiques identifiés tel que séreux, endométrioide, à cellules claires et mucineux. Une analyse génétique réalisée au niveau moléculaire a suggéré un rôle pour des gènes suppresseurs de tumeur localisés sur le bras court du chromosome 3p21.3 dans la pathogénèse du CEO de type séreux. Notre objectif était d’évaluer le profil d’expression de HYAL-1, localisé dans cette même région, dans les différents sous types du CEO, et de vérifier une éventuelle corrélation avec l’expression des récepteurs d’hormones stéroïdiennes. Pour se faire, nous avons analysé par RT-PCR quantitative l’expression de l’ARNm de HYAL-1, des récepteurs d’estrogène (ER-α et ER-β) et du récepteur de progestérone (PR) dans des échantillons de tissus extraits de tumeurs du CEO provenant de deux cohortes indépendantes et dans des lignées cellulaires. Nous avons également réalisé des analyses bioinformatiques à partir de l’expression de ces gènes en ayant recours à une base de données de microarray disponible en ligne et ouverte au public. Par la suite, nous avons mesuré l’activité enzymatique de HYAL-1 dans des lignées cellulaires du CEO et dans des échantillons de plasma. Nos résultats ont montré que l’expression de l’ARNm de HYAL-1 était élevée dans le type à cellules claires et mucineux mais non dans les types séreux et endométrioides, autant dans les échantillons sains que de ceux provenant de tumeurs bénignes. De façon cohérente, le niveau d’ARNm et l’activité enzymatique de HYAL-1 étaient élevés dans les lignées cellulaires à cellules claires et mucineuses. Nous avons aussi démontré qu’il y avait une corrélation inverse entre les niveaux de l’ARNm de HYAL-1 et ceux d’ER-α et PR dans les échantillons de tissus de CEO du type mucineux et à cellules claires. De façon similaire, nous avons noté que l’activité de HYAL-1 était élevée dans le plasma de ces mêmes patients. En conséquence nos travaux proposent HYAL-1 en tant que biomarqueur potentiel dans le cas des CEO de type à cellules claires et mucineux présentant un faible niveau d’expression d’ER-α et PR.

Implications d'AXIN2 et de l'instabilité microsatellite dans le développement des tumeurs du cortex-surrénalien

Les lésions tumorales cortico-surrénaliennes sont majoritairement des adénomes bénins et très rarement des carcinomes. Les altérations génétiques impliquées dans le développement des tumeurs cortico-surrénaliennes sporadiques, plus particulièrement au stade malin, demeurent à ce jour très peu connues. Lors de travaux récents menant à l’identification d’altérations génétiques de β-CATÉNINE nous avons constaté que plusieurs tumeurs présentaient une accumulation nucléo/cytoplasmique de la protéine β-CATÉNINE sans toutefois contenir de mutations pour ce gène. Nous avons donc émis l’hypothèse que, comme pour d’autres types de cancers, d’autres composants de la voie de signalisation Wnt/β-CATÉNINE, tel qu’AXIN2, pourrait être impliqués dans le développement des tumeurs du cortex surrénalien. De plus, plusieurs aberrations dans l’expression d’AXIN2 et de β-CATÉNINE sont associées à des tumeurs présentant de l’instabilité microsatellite dans d’autres types de cancer, notamment le cancer gastrique et colorectal. Nous avons donc étudié une cohorte de 30 adénomes, 6 carcinomes, 5 AIMAH, 3 hyperplasies ACTH-dépendante et 5 PPNAD ainsi que les lignées cellulaires de carcinomes cortico-surrénaliens humains H295R et SW13. Une étude préliminaire du statut MSI a également été réalisée sur 10 tumeurs contenant une mutation pour AXIN2 et/ou β-CATÉNINE. Nous avons trouvé des mutations d’AXIN2 dans 7% des adénomes (2/30) et 17% des carcinomes (1/6) cortico-surrénaliens. L’analyse fonctionnelle des mutations par immunohistochimie, analyse western blot et analyse de RT-PCR en temps réel a révélé une diminution de l’expression d’AXIN2 associée à cette mutation. L’analyse préliminaire MSI a démontré 1 échantillon AIMAH MSI-H, c’est-à-dire instable pour le locus BAT-25 et BAT-26 et 3 autres adénomes sécrétant de l’aldostérone instables seulement pour le locus BAT-26. Ainsi, ces travaux permirent d’identifier une nouvelle altération génétique associée au développement des tumeurs du cortex surrénalien en plus de rapporter pour la première fois la présence de MSI-H dans ce type de tumeurs.

Decompression for Management of Keratocystic Odontogenic Tumor in the Mandible

Keratocystic odontogenic tumor (KCOT) is a benign intraosseous neoplasm of odontogenic origin with high recurrence rate. To date, various conservative or aggressive management strategies have been suggested as a method of treatment. Decompression is a conservative method that has been used in the treatment of large odontogenic cysts. The present paper reports a case of KCOT located in the mandible and discusses the importance of its management using conservative methods. The authors present a case of a 38-year-old patient with a KCOT located in the right mandibular angle and ascending ramus, which was treated by decompression followed by enucleation and curettage. The lesion did not recur during a follow-up period of 3 years after surgery. Preserving important structures of the bone and soft tissue decompression is a method with low morbidity. In addition, according to the literature, decompression has a success rate at least as high as the one of most aggressive treatments.

Conservative Treatment of Odontogenic Myxoma

Odontogenic myxomas (OMs) are nonencapsulated rare benign tumors that can occur in gnathic bones. They are locally invasive and have a high recurrence rate. Radiologically, OMs show a multilocular (in the majority of cases) or unilocular radiolucency, with either distinct or poorly defined margins. Histopathologically, OMs are characterized by spindle-, wedge-, or stellate-shaped cells loosely arranged in an abundant mucoid background. Myxomas are mainly asymptomatic. Radical surgery, excision, and enucleation followed by curettage of the surrounding bony tissue have all been advocated as treatment options. This study presents a successful case of conservative treatment of OMs with a 5-year follow-up.

Large Unicystic Ameloblastoma of the Mandible: Management Guided by Biological Behavior

Ameloblastoma is a true neoplasm of odontogenic epithelial origin. It is a slow-growing benign tumor of the jaw, and patients usually present late after the tumor achieves considerable size to cause facial disfigurement. Diagnosis mainly from tissue biopsy and radiograph findings does assist in differentiating between types of ameloblastoma. Unicystic ameloblastoma is a tumor with a strong propensity for recurrence. There is a difference in biological behavior between mural unicystic ameloblastoma and those which are simply cystic or show intraluminal proliferation. The challenges in the management of this tumor are to provide complete excision in addition to reconstructing the bony defect, to provide the patient with reasonable cosmetic and functional outcome. The authors report a case of a mural unicystic ameloblastoma in a 23-year-old man who was treated by partial resection of the mandible. Biomedical prototypes were used because they provide acceptable precision and are useful for treatment planning.

Conservative Management of a Large Keratocystic Odontogenic Tumor in the Maxilla

Keratocystic odontogenic tumor is characterized by high recurrence rates. Conservative or aggressive management has been suggested as a method of treatment. Decompression is a conservative treatment that has been used in the treatment of large odontogenic cysts. The authors report a case of a 14-year-old patient with a keratocystic odontogenic tumor located in the right maxilla, which was treated by decompression followed by enucleation with curettage. The lesion did not recur on follow-up for 3 years after the enucleation surgery.

Leiomioma vascular bucal: relato de dois casos, revisão da literatura e estudo imuno-histoquímico

INTRODUÇÃO: Os leiomiomas são neoplasias benignas do músculo liso que ocorrem mais comumente nos tratos geniturinário e gastrintestinal, entretanto são raros na cavidade bucal, na qual provavelmente a maioria desses tumores tem sua origem a partir de músculo liso vascular. OBJETIVOS: Relatar dois casos com história clínica semelhante, confrontando seus aspectos com aqueles encontrados na literatura. RELATO DOS CASOS: Dois casos de mulheres na quinta e sexta décadas de vida apresentando nódulo submucoso em ventre lingual. Após exame microscópico que revelou numerosos vasos sangüíneos entremeados a células fusiformes, com núcleos ovalados ou alongados, e exame imuno-histoquímico com positividade para actina de músculo liso nos dois casos, o diagnóstico final foi leiomioma vascular. CONCLUSÃO: O estudo do leiomioma vascular bucal é de extrema importância devido à raridade e semelhança desse com outras lesões da cavidade bucal. A análise imuno-histoquímica é importante para o diagnóstico final do leiomioma.

Lip cavernous hemangioma in a young child

Hemangiomas are benign tumors of infancy and childhood, characterized by a phase of fast growth with endothelial cell proliferation, occurring in 10-12% of children at 1 year of age. It is known that hemangiomas of infancy are most commonly located on the head and neck region (around 60% of cases) and occur more frequently in the lips, tongue, and palate. Approximately 50% of hemangiomas have complete resolution, and 90% of them are resolved up to the age of 9. Complications occur in only 20% of the cases, the most common problem being ulceration with or without infection. The treatment depends on lesion location, size and evolution stage, and the patient's age. Surgery is usually indicated when there is no response to systemic treatments, or even for esthetic reasons, being performed as a simple excision in combination or not with plastic surgery. This paper reports a case of lip cavernous hemangioma in a 4-year-old child, who was submitted to 3 sessions of vascular sclerosis due to the size of the lesion, before undergoing simple excision of the hemangioma. Two years of postoperative clinical follow-up shows treatment success with no recurrence of the lesion.

Epidermal cyst causing facial asymmetry

Epidermoid cysts are rare benign tumors that are derived from the development of abnormally situated ectodermal tissue and are often an incidental finding. They are usually diagnosed between 15 and 50 years of age, with both sexes equally affected. In epidermoid cyst management, complete excision is the therapy of choice. The authors reported a case of a 24-year-old man with an epidermoid cyst located on the left side of the face, on the region of mandibular body, which was treated by complete surgical excision. The patient has been followed up for 2 years without signs of recurrence. Copyright © 2013 by Mutaz B. Habal, MD.

Conservative condylectomy for management of osteochondroma of the mandibular condyle

Osteochondroma is one of the most common benign tumors of the skeleton. This tumor is rare in the craniofacial region, with the most common sites of occurrence being the coronoid process of the mandible and the mandibular condyle. Traditionally, the treatments of these lesions include total condylectomy or local resection of the lesion. Conservative condylectomy procedure with reshaping of the remaining condylar neck and repositioning of the articular disk has been suggested. This article aimed to describe a 35-year-old woman with osteochondroma in the left mandibular condyle who was treated by conservative condylectomy. The patient has been free of recurrence for 2 years, showing good aesthetic and functional stability. Copyright © 2013 by Mutaz B. Habal, MD.

Tissue engineering: Using collagen type i matrix for bone healing of bone defects

Among the many tissues in the human body, bone has been considered as a powerful marker for regeneration and its formation serves as a prototype model for tissue engineering based on morphogenesis. Therefore, collagen type I is one of the most useful biomaterials used in tissue engineering as extracellular matrix components capable to promote bone healing. The literature reveals excellent biocompatibility and safety due to its biological characteristics, such as biodegradability and weak antigenicity, making collagen type I the primary resource in medical applications. Thus, it was also used for tissue engineering including skin replacement, bone substitutes, and artificial blood vessels and valves. The authors describe the treatment of an abscessed apical periodontal cyst and show good outcomes of bone healing, using tissue engineering, as collagen type I matrix. © 2013 by Mutaz B. Habal, MD.

Avaliação da população de células tronco tumorais nas neoplasias da glândula mamária em cadelas

Pós-graduação em Ciência Animal - FMVA

Caracterização de mutações no gene MED12, dos miRNAS mapeados em 7q22 e dos candidatos a regulação do gene HMGA2 em leiomiomas uterinos

Pós-graduação em Ciências Biológicas (Genética) - IBB

Análise prognóstica da imunoexpressão de proteínas relacionadas à transição epitelial-mesenquimal nos carcinomas mamários esporádicos de cadelas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)