Showing papers on "Respiratory epithelium published in 1970"

The role of mucus in transport by cilia.

Abstract: The mucociliary system of respiratory epithelium performs as a major defense mechanism by clearing foreign bodies from the surface of air-exposed cavities. This action is brought about by ciliary b...

Evaluation of Model Systems for Study of Airway Epithelium, Cilia, and Mucus

Abstract: An animal "model" of human lung disease provides a means of testing the effect of irritants and of study in pathogenesis. To relate the model to human lung disease it is necessary to establish the morbid anatomy of the disease. The airway lining system which is under scrutiny here is a. mucus-secreting surface appropriate for the study of chronic bronchitis, the main features of which in man are hypertrophy of mucus-secreting cells, increase in number of goblet cells and extension to the periphery, and an increase in cell activity. The mitotic count is raised and the type of acid glycoprotein modified. These changes can be quantified. They can be reproduced in the experimental animal. The rat is chiefly dealt with here as it has been studied in most detail.

Attachment of two myxoviruses to ciliated epithelial cells.

Abstract: Summary It is thought that influenza and related viruses enter susceptible cells, such as those of tissue cultures and the chorioallantois, by being adsorbed to the surface and then taken in by an active process termed ‘viropexis’. It has been suggested that this active process resembles phagocytosis (Fazekas de St Groth 1948). However, influenza viruses commonly invade the ciliated epithelium of the respiratory tract of the intact host, which is thought not to be actively phagocytic. Organ cultures of such epithelium are extremely susceptible to infection (Hoorn & Tyrrell, 1969). It was therefore of interest to use these to investigate the mechanism of entry of influenza viruses into ciliated epithelial cells; it was uncertain whether the primary target cells would be the ciliated or the mucus-secreting cells. As infection was so efficient, it seemed likely that the virus might ‘exploit’ in some way the sweeping action of the cilia and, rather than being moved on by their activity, might attach and then enter the cells directly or indirectly. Further studies on the entry of virus into non-ciliated cells appeared during this work and these will be discussed later.

The fine structure of the proliferative cells of the mouse intestine as revealed by electron microscopic autoradiography with 3H-thymidine.

Abstract: The duodenal and colonic epithelia in mice were observed with electron microscopic autoradiography 2, 5 and 24 hours after a single injection of 3H-thymidine. After 2 hours, in the duodenum, silver grains are found in many undifferentiated cells, in a few young goblet cells, in some crystal-containing cells, and in some lymphocytes. In the colon after 2 hours silver grains are seen in some undifferentiated cells, and in many young goblet cells. Undifferentiated cells are characterized by a few short microvilli, poorly developed rough-surfaced endoplasmic reticulum, abundant free ribosomes, and a few apical moderately dense granules. In normal animals, absorptive cells seem to arise from undifferentiated cells, and goblet cells — from younger goblet cells. Undifferentiated cells could also become young goblet cells. Crystal-containing cells, which may not be of epithelial origin, proliferate in the epithelium in the adult animal.

Enzyme histochemistry of embryonic nasal mucosa.

Abstract: The prenatal development of rodent nasal mucous membrane has been examined histochemically (lactate dehydrogenase, succinate dehydrogenase, glucose-6-phosphate dehydrogenase, alkaline phosphatase, PAS and PAS with diastase digestion). Localization and intensity of the enzyme systems studied were distinctly different in respiratory and olfactory areas. These differences were demonstrable by at least the second half of gestation in the animals studied. Findings in Jacobson's organs were parallel to those in olfactory areas. Each of the pathways of carbohydrate metabolism examined was present in respiratory epithelium. However, intensity was less, appeared later and was more variable in intracellular localization than that found in olfactory areas. Based on enzyme staining olfactory epithelium seemed metabolically more active than respiratory mucosa. Apical portions of olfactory epithelium stained most intensely for oxidative enzyme systems, particularly the glucose-6-phosphate dehydrogenase system. These areas of high activity were thought to represent apices of supporting cells rather than receptor cells. This localization of a pentose phosphate shunt enzyme system was related speculatively to ion transport in these cells. Alkaline phosphatase was relatively slight in respiratory areas during the ages studied. The basal portions of olfactory epithelium stained positively for alkaline phosphatase. Since hydrolytic enzymes have been thought to be important in the mechanism of olfaction, its demonstration in these tissues suggests that this portion of the olfactory mechanism is present by midgestation in the rodents studied.

The possible value of certain cells for the propagation of respiratory viruses

Abstract: A strain of HeLa cells, L 132 cells and roller tube cultures of human embryo respiratory epithelium were compared with standard laboratory systems for the propagation of certain rhinoviruses, parainfluenza viruses and some others.