The disribution of ganglioside sialidase on developing mouse tooth germ

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Ganglioside sialidase is one type of the animal sialidases, whose activity is innately localized on cell membrane by biological definition. This project aimed at confirming the morphological localization and biological role of this enzyme. An immunocytochemical study proved the enzyme being localized on cell membrane of COS cells transfected with bovine cDNA of the enzyme, and of skeletal muscle cells in transgenic mice expressed with the human cDNA. To elucidate a biological role of the enzyme, a histological study was done in incisors of abovementioned transgenic mice. Mouse incisors continue to grow during the animal life. Therefore we can study an effect of some experimental condition on tooth formation at any time of the animal life. The histological changes of the enamel organ and tooth were ambiguous in the transgenic mice because of inadequate tissue fixation with paraformaldehyde. To get good histological features, the tissue fixation method needed to be improved. Mice under anesthetization were fixed with the chemical fixative which was infused into the left ventricle through a catheter by using a peristaltic pump. The fixative circulating the body along blood vessels was drained from the right atrium cut open. The shorter surgical operation time to insert a catheter into the left. ventricle you will take, the better histological features you will get. A catheter was devised for shortening the surgical operation time. The best catheter was a polyethylene tubing 0.9mm in diameter connected to a metal needle (26 gauge) at the one end. The left ventricle was punctured by the needle after thoracotomy. To hold the needle in place the heart and needle were glued by using Aron Alpha A (Toagosei Co., Ltd.), one of surgical glues. Taking much time for improving the tissue fixation method, the histological study has not yet been completed.