Spontaneous healing of the tympanic membrane after traumatic perforation in rats / Cicatrização espontânea da membrana timpânica após sua perfuração traumática: estudo experimental em ratos,

OBJECTIVE: The objective of the present study was to assess the healing of traumatic tympanic membrane perforation in rats. METHODS: The tympanic membrane from male Wistar rats was perforated in the anterior and posterior portions to the handle of the malleus. Five tympanic membranes were evaluated 3 days after tympanic perforation; 5 after 5 days; 5 after 7 days; 3 after 10 days; and 4 after 14 days. The tympanic membranes were submitted to histopathological evaluation after hematoxylin-eosin staining. RESULTS: Tympanic membrane closure occurred at about 7-10 days after injury and the healing process was complete by day 14. The proliferative activity of the outer epithelial layer was present close to the handle of the malleus and to the tympanic annulus. CONCLUSION: The spontaneous healing process of the tympanic membrane starts from the outer epithelial layer, with later healing of the lamina propria and the mucosal layer. .

OBJETIVOS: Avaliar o reparo cicatricial de perfurações traumáticas da membrana timpânica em ratos. MÉTODO: A membrana timpânica de ratos Wistar machos foram perfuradas nas porções anterior e posterior ao cabo do martelo. Cinco membranas timpânicas foram avaliadas 3 dias após perfuração timpânica; 5 após 5 dias; 5 após 7 dias; 3 após 10 dias; e 4 após 14 dias. As membranas timpânicas foram submetidas à avaliação histopatológica após coloração com hematoxilina- eosina. RESULTADOS: O fechamento da membrana timpânica ocorreu em torno de 7 a 10 dias após perfuração traumática, e o processo de cicatrização estava completo no 14° dia. A atividade proliferativa da camada epitelial externa foi identificada próxima ao cabo do martelo e ao ânulus timpânico. CONCLUSÃO: O processo de cicatrização espontânea da membrana timpânica se inicia com a camada epitelial externa, com posterior cicatrização da lâmina própria e da camada mucosa. .

Neutrophil transepithelial migration: role of toll-like receptors in mucosal inflammation

The symptomatic phases of many inflammatory diseases are characterized by migration of large numbers of neutrophils (PMN) across a polarized epithelium and accumulation within a lumen. For example, acute PMN influx is common in diseases of the gastrointestinal system (ulcerative colitis, Crohn's disease, bacterial enterocolitis, gastritis), hepatobiliary system (cholangitis, acute cholecystitis), respiratory tract (bronchial pneumonia, bronchitis, cystic fibrosis, bronchiectasis), and urinary tract (pyelonephritis, cystitis). Despite these observations, the molecular basis of leukocyte interactions with epithelial cells is incompletely understood. In vitro models of PMN transepithelial migration typically use N-formylated bacterial peptides such as fMLP in isolation to drive human PMNs across epithelial monolayers. However, other microbial products such as lipopolysaccharide (LPS) are major constituents of the intestinal lumen and have potent effects on the immune system. In the absence of LPS, we have shown that transepithelial migration requires sequential adhesive interactions between the PMN beta2 integrin CD11b/CD18 and JAM protein family members. Other epithelial ligands appear to be abundantly represented as fucosylated proteoglycans. Further studies indicate that the rate of PMN migration across mucosal surfaces can be regulated by the ubiquitously expressed transmembrane protein CD47 and microbial-derived factors, although many of the details remain unclear. Current data suggests that Toll-like receptors (TLR), which recognize specific pathogen-associated molecular patterns (PAMPs), are differentially expressed on both leukocytes and mucosal epithelial cells while serving to modulate leukocyte-epithelial interactions. Exposure of epithelial TLRs to microbial ligands has been shown to result in transcriptional upregulation of inflammatory mediators whereas ligation of leukocyte TLRs modulate specific antimicrobial responses. A better understanding of these events will hopefully provide new insights into the mechanisms of epithelial responses to microorganisms and ideas for therapies aimed at inhibiting the deleterious consequences of mucosal inflammation.

Morphological observations of the sensory nerve endings of the Calomys callosus' lingual mucosa, employing the silver impregnation method

Estudaram-se as características morfológicas das terminaçöes nervosas sensitivas da mucosa lingual de Calomys callosus, empregando-se a técnica de impregnaçäo pela prata. Para a obtençäo das peças, cada animal foi anestesiado com injeçäo intraperitonial de tionembutal sódico. As peças foram fixadas em soluçäo de formalina a 10 por cento por um período de 20 dias à temperatura ambiente e cortes espessos de 40-60 micrometros foram obtidos em criostato Linde. As preparaçöes foram coradas pela técnica de impregnaçäo pela prata. De acordo com os nossos resultados podemos concluir que: 1) todas as regiöes (anterior, média e posterior) da mucosa dorsal da língua de Calomys callosus possuem terminaçöes nervosas sensitivas; 2) as terminaçöes nervosas podem ser simples ou complexas localizando-se no tecido conjuntivo da lâmina própria ou no interior das papilas conjuntivas das papilas filiformes, fungiformes e valadas, 3) as terminaçöes nervosas livres no interior das papilas fungiformes dispöem-se longitudinalmente ou formando uma rede complexa de fibras nervosas terminais

histological study of human respiratory nasal mucosa: observations on glands

Mucosa of nasal septum, inferior turbinate and inferior meatus from eighteen autopsy cases of both sexes was studied. Observations showed that stroma was rich in connective tissue, blood vessels and glands. Collagen fibers were more than elastic fibers. Blood vessels were mostly subepithelial, and periglandular. Glands were of mixed type. The difference between serous and mucous cells of the septal, meatal and conchal regions of the same side was statistically significantant [p < 0.05]. In septal and inferior meatal region, the ratio of serious and mucous cells was approximately 2:1. In inferior conchal region their ratio was approximately 3:1

Development of the mucociliary system in the eustachian tube and middle ear: murine model

In order to describe the developmental anatomy of the murine eustachian tube and its related structures, seventy six mice of ages ranging from gestational day 11 to postnatal day 21 were investigated through the light and electron microscopic observations. Development of the ciliated cells was seen concurrently in both the eustachian tube and middle ear on the 16 th gestation day, one day earlier than the epithelial secretory cells appeared in both the eustachian tube and middle ear. The number of ciliated cells and secretory cells increased rapidly after birth. Tubal glands were well identified with evidence of secretory activity around the time of birth. Thus, the findings of this study indicate that the mucociliary defense system starts to develop during the fetal stage and is well established immediately after birth.