We have used intratracheal instillation of bleomycin in rats to study the microanatomical changes of blood vessels associated with lung fibrosis. Bleomycin is a toxic cytostatic drug employed in classical models of lung fibrosis. Wistar rats were submitted to intratracheal injection of 1.5 units of bleomycin and sacrificed 2.5 months later, a timing when marked fibrosis of the lung is observed. We casted the vascular tree of the rat lungs by perfusion with a methacrylate resin. These casts were studied by scanning electron microscopy. Lung tissue was also studied by light microscopy and thin section electron microscopy. The major vascular modifications observed in the bleomycin-treated rats were: (1) neoformation of an elaborate network of vessels located in the peribronchial domains of the lung, and (2) distortion of the architecture of alveolar capillaries. By light microscopy, it was clear that the newly formed vascular network was located in regions of fibrosis (which in the resin casts were digested away). These neoformed vessels appeared to originate from bronchial arteries. Thin section electron microscopy revealed that endothelial cells of the neoformed vessels were plump, presented large nuclei, and showed numerous pinocytotic vesicles that were also observed in subendothelial pericytes. The alveoli of the bleomycin-treated rats were heterogeneous in size and shape in contrast with the homogeneity of alveoli of control animals. The alveolar capillaries of fibrotic lungs appeared to occupy a larger volume of the alveolar wall than alveolar capillaries of control rats. Our findings indicate that lung fibrosis encompasses marked changes of the vascular system, namely, the neoformation of vessels and the rearrangement of alveolar capillaries. These structural changes suggest that fibrotic transformation of the lung is associated with the local generation of angiogenic stimuli.

The article analyzes the practice of physicians and nurses working on the Family Health Programme (Programa de Saúde da Família or PSF, in Portuguese).A questionnaire was used to assess the evidences of assimilation of the new values and care principles proposed by the programme.The results showed that a great number of professionals seem to have incorporated the practice of home visits, health education actions and planning of the teams' work agenda to their routine labour activities.

We have used scanning electron microscopy (SEM) to screen the entire epithelial surface of the cervical trachea of the adult rat. This scrutiny revealed that the density of ciliated cells along this epithelium follows a repetitive pattern: circular strips of high density of ciliated cells alternate with areas of low density of the same cells. Cilia-poor strips of the tracheal epithelium were seen on areas of cartilage rings; here, ciliated cells made up 32% of the total surface of the tracheal lining. Cilia-rich areas filled the epithelial surface at the tracheal ligaments (i.e., the regions located in-between the rings); here, ciliated cells occupied 65% of the tracheal lumen. In the cilia-poor zones, the density of ciliated cells decreased from its periphery into its center, where cilia were virtually absent. No differences in this pattern of the tracheal epithelium were seen between young adult and older rats. We conclude that the respiratory epithelium expresses density zonation of ciliated cells on the trachea of adult rats. We propose that the high concentration of ciliated cells on the regions of epithelium located at the tracheal ligaments suggests that these zones are electively committed in the clearance of the respiratory airway.

The work environment of cotton mill rooms of modern textile plants is characterized by noise pollution. We have taped and reproduced this noisy environment to study its effects on experimentally exposed rats. Because we have previously documented that chronic noise causes alterations in the respiratory epithelium, we have focused our investigation on the morphology of the tracheal lining. Wistar rats were exposed to the textile-type noise from 1 up to 7 months, with an average 40 hours weekly exposure of the animals. The rats were sacrificed monthly and the tracheas were studied by scanning electron microscopy (SEM) to quantify the areas of the airway lining that were covered by ciliated, serous or other cells of the epithelium. We found that noise exposure of the rats caused a significant loss of tracheal ciliated cells; an increased density of serous cells on the epithelium balanced this change. This modification of the rat trachea was already established after 1 month of noise treatment of the animals; it did not change significantly throughout the 7-month course of the herein investigation. Loss of ciliated cells was more intense in areas of the tracheal epithelium located between the regions of cartilage rings. We conclude that the ciliated cell is an elective target for damage caused on the respiratory epithelium by the workplace noise occurring in cotton mill rooms. This modification of the respiratory epithelium is likely to impair clearance of the airways since this function depends on the activity of ciliated cells.