Anatomical description of the extratemporal facial nerve under high-definition system: a microsurgical study in rats

Purpose: To describe the microsurgical anatomical aspects of the extratemporal facial nerve of Wistar rats under a high-definition video system. Methods: Ten male Wistar rats (12­15 weeks old), without veterinary diseases, weighing 220­280 g, were used in this study. All animals in this study were submitted to the same protocol and by the same surgeon. A 10-mm incision was made below the bony prominence of the right or left ear, and extended towards the angle of the mandible. The dissection was performed and the main branches of the facial nerve were dissected. Results: The main trunk of the facial nerve has a length of 0.88 ± 0.10 mm and a length of 3.81 ± 1.03 mm, measured from its emergence from the stylomastoid foramen to its bifurcation. Seven branches originating from the facial nerve were identified: posterior auricular, posterior cervical, cervical, mandibular, buccal, temporal, and zygomatic. Conclusions: The anatomy of the facial nerve is comparable to that of humans, with some variations. The most observed anatomical division was the distribution in posterior auricular, posterior cervical, cervical, mandibular, buccal, temporal, and zygomatic branches. There is no statistical difference between the thickness and distance of the structures compared to the contralateral side.

Optimization of methods to assess mitochondrial DNA in archival paraffin-embedded tissues from mammary canine tumors / Otimização dos métodos para avaliar o DNA mitocondrial obtido a partir de tumores mamários caninos incluídos em parafina

In this study we describe the alterations used to extract and amplify mitochondrial desoxyribonucleic acid (DNA) from formalin-fixed paraffin-embedded samples of canine mammary tumors. The epithelial and mesenchymal components (chondromyxoid and chondroid) of each tumor, as well as the normal mammary gland tissues, were manually microdissected from 19 mixed canine mammary tumors (10 benign mixed tumors and nine carcinomas arising in mixed tumors). DNA was extracted by Invisorb® Spin Tissue Mini Kit, with protocol changes proposed by the manufacturer. A 273-bp fragment was amplified by polymerase chain reaction (PCR) and submitted to automatic sequence analysis. The fragment was successfully analyzed in 100 percent of the samples. However, an additional lysis step, the reduction of volume in buffer solutions and PCR, a higher annealing temperature and an increase in the number of PCR cycles were required. The initial PCR products were diluted and re-amplified in six samples so that they could be successfully analyzed.

A presente comunicação descreve as modificações usadas para extrair e amplificar o DNA mitocondrial obtido de amostras de tumores mamários caninos fixados em formol tamponado a 10 por cento e incluídos em parafina. Os componentes epiteliais e mesenquimais (condromixóide e condróide), bem como a mama normal adjacente, foram microdissectados manualmente de 19 tumores mamários (10 tumores mistos benignos e nove carcinomas em tumores mistos). O DNA foi extraído utilizando-se o Invisorb® Spin Tissue Mini Kit com modificações do protocolo proposto pelo fabricante. Um fragmento de 273-pb foi amplificado por reação em cadeia da polimerase (PCR) e seqüenciado em seqüenciador automático. O fragmento foi analisado em 100 por cento das amostras, entretanto modificações como lise adicional, redução do volume das soluções de extração e PCR, aumento da temperatura de anelamento e do número de ciclos de amplificação foram necessárias. Em seis amostras os produtos iniciais de PCR foram diluídos e reamplificados para obtenção de sucesso.

Molecular approach of the fragile chromosomal region Xq31-34 in cattle (Bos taurus) by microdissection and DOP-PCR / Aproximação molecular da região cromossômica frágil Xq31-34 em bovinos (Bos taurus) utilizando microdissecação cromossômica e DOP-PCR

Fragile sites (FS) are chromosomal regions where the normal compactation of chromatine is not observed. FRAXA (Fra Xq27.3, X sexual chromosome) is one of the most studied FS in humans. FRAXA is an expansion of the trinucleotide CGG located in the gene FMR-1. In cattle, sites of chromosomal fragility were reported in BTAX, associated with different pathologies and fertility impairment. Chromosomal microdissection has became a valuable tool for isolating chromatine fragments. In this work, it was combined the chromosomal microdissection technique with DOP-PCR in order to carry out a molecular analysis of the fragile chromosomal region BTAXq31-34. In that region, polymorphic DNA-RAPD sequences (GC rich) are present and sequences of the gene FMR-1 are missing. The results showed the usefulness of the microdissection-DOP-PCR technique for molecular characterization of fragile chromosomal sites in cattle.

Os sítios frágeis (FS) são regiões de cromossomo onde a compactação normal da cromatina não é realizada. O FRAXA (Fra Xq27.3, cromossomo sexual X) é um dos FS mais estudados em seres humanos. O FRAXA apresenta expansão do trinucleotídeo CGG localizado no gene FMR-1. Em bovinos, existem estudos informando sobre fragilidade cromossômica em BTAX associada com diversas patologias e alterações na fertilidade. A microdissecação cromossômica é uma valiosa técnica para isolar fragmentos de cromatina. Neste trabalho, combinou-se a técnica de microdissecação de cromossomo com DOP-PCR para executar a análise molecular da região do sitio frágil cromossômico BTAXq31-34. Naquela região estão presentes seqüências do polimorfo DNA-RAPD (rico em GC), em que as seqüências do gene FMR-1 estão ausentes. Os resultados mostram a utilidade da técnica de microdissecação-DOP-PCR para a caracterização molecular de sítios frágeis cromossômicos em bovinos.