Avaliação da técnica de esfoliação com escova citológica para coleta de células conjuntivais em gatos sadios: comparação entre a face palpebral da membrana nictitante e a conjuntiva palpebral / Evaluation of the exfoliative cytology technique using cytobrush in healthy cats: Comparison between palpebral surface of nictitating membrane and palpebral conjunctiva

A citologia conjuntival é um importante meio de diagnóstico de afecções da superfície ocular. Buscam-se técnicas que forneçam quantidade e qualidade celular, com uso de instrumentos que provoquem mínimo trauma e que diminuam as chances de danos iatrogênicos ao olho. Existem diversas técnicas de coleta de células, entre elas encontram-se: impressão, esfoliação e punção por agulha fina. Dentre os métodos utilizados para esfoliação, o uso da escova citológica fornece resultados superiores em vários parâmetros, incluindo a qualidade das células. Estudou-se a citologia conjuntival por esfoliação com escova citológica, utilizada para coleta de material da cérvix uterina, tendo como objetivos determinar se tal instrumento se adequaria à coleta de material da face palpebral da membrana nictitante e da conjuntiva palpebral de felinos sadios. Foram avaliados os seguintes parâmetros: facilidade de execução da técnica, possibilidade de ocorrência de danos iatrogênicos e quantidade e qualidade de células coletadas. Cinquenta gatos machos (58%) e fêmeas (42%), com ou sem raça definida, participaram do estudo. Apenas gatos isentos de alterações oculares no exame físico foram incluídos. A escova citológica se mostrou um instrumento de fácil utilização, que fornece células em quantidade satisfatória e com morfologia preservada. Comparada a conjuntiva palpebral, a face palpebral da membrana nictitante se mostrou um local mais adequado à realização da coleta de amostras citológicas, pela maior facilidade de execução da técnica e menor possibilidade de danos iatrogênicos. No que diz respeito à quantidade e qualidade celular, não houve diferença significativa entre os dois locais de coleta. Foi possível observar células provenientes das diferentes camadas do epitélio conjuntival com predomínio de células intermediárias e ausência de células caliciformes.

Conjunctival cytology is an important diagnostic method for ocular superficial diseases. There are several techniques to collect cells, including impression, exfoliation and fine needle aspiration. These techniques have shown individual variations depending on method and instrument used on the collection process. Techniques with instruments that cause low damage and decrease iatrogenic damage risks to the eyes, providing cellular quantity and quality, are wanted. Exfoliative cytology techniques are frequently used in human and veterinary medicine. Among the methods used for exfoliation, cytobrush provides better results on many parameters, including cell quality. The use of conjunctival exfoliation cytology using cytobrush (brush usually used for cervix cytology) was investigated. The aim was to determine if this technique would provide an adequate number and quality of conjunctival third eyelid cells of cats; to compare these samples with those collected by the same way from conjunctival area and to determine a cytologic pattern of this region. This comparison would provide information about technique security, possible damage risks and collected cells characteristics. Cats were evaluated through physical and routine ophthalmic exam. Fifty domestic cats, males (58%) and females (42%), of any breed were accepted. In the study were included only animals free of ocular and systemic changes. Cytobrush showed an easy and usefulness instrument, that provides satisfactory amount of cells with preserved morphology. Compared to palpebral conjunctiva, palpebral surface of nictitating membrane showed a most adequate site to cytological sample collect, greater facility of technical perform and smaller possibility of iatrogenic damage. In respect to quality and quantity of cells there was no significant difference between collect sites. It was possible to observe epithelial cells of conjunctiva from different stratum with predominance of intermediate cells and absence of goblet cells.

Distribution of goblet cells and MUC5AC mRNA in the canine nictitating membrane.

This study evaluated the distribution of goblet cells and the expression of MUC5AC mRNA in the canine nictitating membrane. The distribution of goblet cells in the nictitating membrane and temporal bulbar conjunctiva of beagle dogs was examined by histochemical analysis of impression cytology specimens and frozen sections. MUC5AC mRNA was detected by the reverse transcription polymerase chain reaction (RT-PCR). The distribution of MUC5AC mRNA was also examined by in situ hybridization using digoxigenin-labeled antisense and sense RNA probes. Histochemical analysis showed that the canine nictitating membrane epithelium contained many more periodic acid-Schiff positive goblet cells, particularly on the palpebral side, compared with the temporal bulbar conjunctiva. RT-PCR revealed that MUC5AC was expressed in both the nictitating membrane and in conjunctival tissue. When the distribution of MUC5AC mRNA was assessed by in situ hybridization, its expression was high on the palpebral side of the nictitating membrane and low in the temporal bulbar conjunctiva. MUC5AC mRNA expression corresponded with the distribution of goblet cells by histochemical examination. In conclusion, there were numerous goblet cells in the canine nictitating membrane epithelium, particularly on the palpebral side, and MUC5AC mRNA was expressed in the nictitating membrane epithelium at locations corresponding to the goblet cells.

[Morphology and structure of the nictitating membrane cartilage in mammals]. / Morphologie et structure du cartilage de la membrane nictitante des Mammifères.

In 30 species of Mammals of varying body size (from rat to elephant), the form, dimensions and structure of the cartilage of the third eyelid were studied. The cartilage is a thin lamina concave in its corneal side, usually elongated in the oro-aboral direction. In the most species studied the outline of the cartilage may be inscribed in a triangle with a oral base, a dorsal margin, a ventral margin and an aboral apex. A study of stained sections revealed, in more than half of species, the presence of elastic fibres in the aboral part of cartilage; these fibres are particularly numerous, but non uniformly distributed, in the Equidae, lion and Suidae.

The cartilage of the third eyelid: a comparative macroscopical and histological study in domestic animals.

The purpose of this comparative study was to evaluate morphological differences between the cartilages of the third eyelid in dogs, cats, pigs, cows, small ruminants and horses. For that reason a total of 83 third eyelids were investigated. By the aid of a modified maceration technique, the three-dimensional form of the cartilage could be demonstrated for the first time. Generally, the cartilage consists of a long narrow appendix which is followed by a variable crossbar. In dogs the appendix is cone shaped in the basal end and extends to form a triangular plate. The former is crescent-like in shape and has a marked bulge. The cartilage of the cat consists of an appendix which is enlarged in the proximal end as compared to the dog. The crossbar resembles a reverse s-form with ends tapering off to a point. In contrast pig and cow cartilage possess a typical anchorform whereas the cartilage of small ruminants starts with a thin rod which extends in a slightly curved form ending in an oval plate. The crossbar is crescent-like in these animals. In the horse the base of the cartilage is surrounded by a massive fatty tissue and the crossbar has a characteristic hook-form. Moreover, there are significant differences in regard to the quality of the cartilage, especially concerning the presence and distribution of elastic fibres. In cats and horses the elastic fibres of the adjacent connective tissue penetrate the perichondrium. Additionally, the centre of the cartilage shows a very dense network consisting of fine elastic fibres. In dogs, pigs, cows and small ruminants the cartilage consists of hyaline quality and only in the neighbouring connective tissue are some elastic fibres detectable.

Functional morphology of the nictitating membrane in the domestic cat.

Morphological differences between the corneal and palpebral surfaces of the nictitating membrane of the domestic cat were examined using histology, histochemistry and the scanning electron microscope. Both surfaces are covered by one or two layers of epithelial cells. The epithelium contains numerous goblet cells, particularly on the palpebral side. These cells revealed binding sites for six lectins as well as positive PAS reactivity, and alcianophilia at both pH 2.5 and pH 3.5. Numerous lymph follicles located on the corneal side make the epithelium look like lymphoepithelial tissue. Accumulations of lymphatic tissue may also be found on the palpebral side. Scanning electron micrographs showed microvilli on the epithelial surfaces. The function of the cat nictitating membrane is discussed on the basis of our findings and those of other authors. Movements of the nictitating membrane alternate between active and passive phases of gliding. The membrane as a whole effectively protects the nasal portion of the bulb from dust, dehydration and pathogens.

Russel bodies-containing cells in the Harderian gland of the chicken in relation to different immune conditions.

The modulation of the number of Russel bodies-containing plasma cells in the Harderian gland under different experimentally induced immune conditions is reported. The findings support the conception of an immunologic function of the Harderian gland which is similar to the function of the thymus on the one hand, and to the function of the bursa of Fabricius on the other.