Histopathological evaluation of urethroplasty with dorsal buccal mucosa: an experimental study in rabbits

PURPOSE: Buccal mucosa is a widely accepted tissue for urethroplasty. The exact healing and tissue integration process, mainly the histological characteristics of dorsal buccal mucosa graft urethroplasty when used dorsally to reconstruct the urethral plate has not previously been assessed, and thus we developed an experimental model to address this question. MATERIALS AND METHODS: In 12 New Zealand rabbits (weight 2.5 kg) we surgically created a dorsal penile urethral defect. A buccal mucosa graft was sutured to the corpora and tunica albuginea, and the ventral urethra anastomosed to this new urethral plate. The animals were divided in three groups and sacrificed 1, 3 and 6 weeks after surgery (groups 1, 2 and 3). A retrograde urethrogram was obtained at autopsy in the last group and the penis analyzed histologically with hematoxylin-eosin and Masson's staining. RESULTS: The urethrograms showed no evidence of fistula or stricture. In group 1 the histopathological analysis showed submucosal lymph-mononuclear inflammatory edema, numerous eosinophils and squamous epithelium integrated into the adjacent urothelium. In group 2 there was no evidence of an inflammatory response but rather complete subepithelial hyaline healing, which was more marked in group 3. CONCLUSION: Healing of buccal mucosa grafts to reconstruct the urethral plate can be achieved by total integration of the squamous epithelium with the urothelium, maintaining the original histological properties of the graft with no fibrosis or retraction.Federal University of São Paulo Divisions of UrologyFederal University of São PauloUNIFESP, Divisions of UrologyUNIFESPSciEL

A preoperative diagnostic test that distinguishes benign from malignant thyroid carcinoma based on gene expression

Accurate diagnosis of thyroid tumors is challenging. A particular problem is distinguishing between follicular thyroid carcinoma (FTC) and benign follicular thyroid adenoma (FTA), where histology of fine-needle aspirates is not conclusive. It is often necessary to remove healthy thyroid to rule out carcinoma. in order to find markers to improve diagnosis, we quantified gene transcript expression from FTC, FTA, and normal thyroid, revealing 73 differentially expressed transcripts (Pless than or equal to.0001). Using an independent set of 23 FTCs, FTAs, and matched normal thyroids, 17 genes with large expression differences were tested by real-time RT-PCR. Four genes (DDIT3, ARG2, ITM1, and C1orf24) differed between the two classes FTC and FTA, and a linear combination of expression levels distinguished FTC from FTA with an estimated predictive accuracy of 0.83. Furthermore, immunohistochemistry for DDIT3 and ARG2 showed consistent staining for carcinoma in an independent set 59 follicular tumors (estimated concordance, 0.76; 95% confidence interval, [0.59, 0.93]). A simple test based on a combination of these markers might improve preoperative diagnosis of thyroid nodules, allowing better treatment decisions and reducing long-term health costs.Universidade Federal de São Paulo, Mol Endocrinol Lab, Div Endocrinol, Dept Med, São Paulo, BrazilUniversidade Federal de São Paulo, Div Genet, Dept Morphol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Pathol, São Paulo, BrazilDuke Univ, Med Ctr, Dept Biostat & Bioinformat, Durham, NC USAJohns Hopkins Univ, Sch Med, Dept Neurosurg, Baltimore, MD 21205 USAUniversidade Federal de São Paulo, Mol Endocrinol Lab, Div Endocrinol, Dept Med, São Paulo, BrazilUniversidade Federal de São Paulo, Div Genet, Dept Morphol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Pathol, São Paulo, BrazilWeb of Scienc