Técnicas anatômicas no ensino da prática de anatomia animal / Anatomical techniques in the animal anatomy practice teaching

A preocupação quanto a conservação de peças anatômicas existe a mais de 5 mil anos, pois o uso de peças cadavéricas são indispensáveis para o ensino, contribuindo com a melhora das habilidades aplicativas, assimilativas e compreensivas da disciplina. Esse trabalho propõe maior utilização das técnicas apresentadas em laboratórios de anatomia, visando abolir o uso do formol como conservante, permitindo um ambiente agradável para a prática da relação ensino-aprendizagem. Para isso foram utilizadas quatro técnicas anatômicas, a criodesidratação, glicerinação, injeção de látex e injeção de vinilite seguido de corrosão, que foram executadas utilizando cães, gatos e órgãos provenientes de doações. Com a criodesidratação e glicerinação os materiais anatômicos ficaram consideravelmente mais leves do que eram quando mantidos em formol, mantendo-se inodoros, diferente do evidenciado na utilização de formol e outros conservantes. As estruturas de estudo das peças ficaram intactas, de fácil visualização e o armazenamento passou a ser feito em caixas fechadas sem qualquer tipo de liquido, mantendo-se assim por até 3 anos. As técnicas de injeção de látex e vinilite seguido de corrosão mostraram total eficiência preenchendo os sistemas injetados, podendo visualizar as ramificações e todo caminho percorrido no sistema circulatório. As quatro técnicas anatômicas estudadas nesse trabalho mostraram ser suficientes para atender as necessidades dos estudantes quanto ao estudo da anatomia, devido à perfeita evidenciação de estruturas externas e internas dos animais.

The concern about preservation of anatomical specimens in existence for over 5000 years, since the use of anatomical parts, are indispensable for teaching and contribute for the improvement of applicative, assimilative skills and understanding of the discipline. This paper proposes better use of techniques in anatomy laboratories, to abolish the use of formaldehyde as preservative, allowing a pleasant environment for the practice of teaching/learning relationship. For this purpose, we used four anatomical techniques, (1) the cryodehydration, (2) glycerin conservation, (3) latex injection and (4) vinylite injection followed corrosion, we executed using dogs, cats and organs from donations. With cryodehydration and glycerin conservation the anatomical materials were considerably lighter than when kept in formaldehyde, odorless unlike in the use of formaldehyde and other preservatives. The structures to be studied were kept intact, easily to view, and the specimens could be stored in closed boxes without any liquid, thus remaining for up to 3 years. The Injection techniques (latex and vinylite followed by corrosion) showed total efficiency to inject filling systems, and allowed a clear view of all ramifications and paths of the circulatory system. The four anatomical techniques studied were shown to be sufficient to meet the needs of students to study anatomy due to the perfect disclosure of external and internal animal structures.

Comparison of cryoprotectants in the preservation of Theileria parva sporozoites using an in vitro infectivity assay.

An in vitro infectivity assay was used to examine five cryoprotectants for their suitability for preserving Theileria parva sporozoites. All five were capable of preserving T. parva sporozoites through freezing, the optimal concentrations being 7.5% for glycerol, 5% for dimethyl sulphoxide (DMSO), poly (vinylpyrrolidone) (PVP) and poly(ethylene glycol) (PEG), and 2.5% for hydroxyethyl starch (HES). When the five cryoprotectants were compared at their optimal concentrations, using a modification of the standard method of stabilate preparation, glycerol was significantly better than the others (p < 0.05). Measurement of the effects of each cryoprotectant on the osmolality of the media revealed that glycerol and DMSO elevated the osmolality significantly (p < 0.05). Resuscitation of glycerol-preserved sporozoites required the presence of glycerol in the diluent to maintain infectivity. Studies on the effects of equilibration time in glycerol on the infectivity of sporozoites showed that those frozen immediately after mixing (2 min) were as infective as those frozen after 60 min of equilibration.

Inhibition of nuclear DNA-dependent RNA polymerases from mouse ascites tumors and liver by glycerol.

Nuclear DNA-dependent RNA polymerases were isolated from Ehrlich ascites carcinoma, TA3 ascites adenocarcinoma, and mouse liver and tested for inhibition by glycerol. The results confirm the finding of Smith and Duerksen ((1975) Biochem. Biophys. Res. Commun. 67, 916-923) that glycerol may inhibit nuclear RNA polymerase II, but because different grades of glycerol inhibited mouse liver RNA polymerase IIa to different extents, it is suggested that an inhibitory contaminant is present. RNA polymerases IIa and IIb from the two tumors and mouse liver were proportionately inhibited by A.C.S. reagent-grade glycerol at concentrations above 10%. RNA polymerase Ia from liver and the TA3 tumor was not inhibited by any concentration of glycerol tested (2-32.3%), but RNA polymerase Ia from Ehrlich carcinoma was inhibited by glycerol concentrations above 16%.