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Biomedical subjects

M E Lathrop

Publications and source records attributed to M E Lathrop.

5 recordsLinked to original sources
PubMed1995

The effects of imidazole on pulmonary damage induced by bleomycin.

Bleomycin may produce diffuse pulmonary damage. Our objective was to evaluate the effect of imidazole, a thromboxane-synthetase inhibitor, on pulmonary damage induced by endotracheal instillation of bleomycin in rats. Bleomycin 1 U/100 g body weight produced diffuse pulmonary damage and increased number of inflammatory cells after 3 days, hemorrhage and focal fibrosis after 7 days, and diffuse fibrosis and pneumocyte hyperplasia after 14 to 30 days. Imidazole 5 mg/100 g body weight, given intraperitoneally 30 min before bleomycin, decreased the 3rd day lesions without altering the histopathology in subsequent periods. Imidazole reduced (p < 0.05) the increases in cell number (3rd and 14th days) as well as in proteins in bronchoalveolar lavage (3rd day), without modifying the increase in phospholipids observed in rats treated with bleomycin. We conclude that imidazole decreases initial bleomycin-induced pulmonary damage, but it does not interfere with fibrosis and late development of epithelial hyperplasia.

Animals↗
PubMed1992

Comparison of the subcellular distribution of alveolar surfactant in two mammalian species of similar body weight: cat and rabbit.

1. We studied the total amount and subcellular distribution of alveolar surfactant, extracted through bronchoalveolar lavage of anesthetized cats and rabbits. This was correlated to several morphometric and ventilatory variables of these animals. 2. Lung weight was significantly larger in the cat while respiratory frequency and minute ventilation were significantly larger in the rabbit. No significant differences were observed in tidal volume, total lung capacity, P(a)O2, P(a)CO2 and pH(a). 3. While both species had similar protein contents in the bronchoalveolar lavage, rabbits had larger phospholipid contents, mostly distributed in the lighter, more active subfractions. 4. With regard to the estimated values obtained from allometric equations derived for mammals, the rabbit presented a lung weight of nearly one-third of the estimated one, an exceedingly larger minute ventilation (by nearly 60%) and a respiratory frequency twice the calculated one. 5. We suggest that the different distribution of alveolar surfactant in these species may be explained by disparities in their ventilatory demands, the rabbit having a higher respiratory frequency and a larger minute ventilation, performed by a mass of lung tissue lower than that corresponding to its body mass.

Animals↗
PubMed1991

Factors affecting distribution of alveolar surfactant during resting ventilation.

Few studies have been done to establish the ventilatory factors affecting alveolar surfactant under resting conditions. Experiments in which ventilatory variables were recorded for 4 h were performed in 12 adult cats breathing spontaneously under pentobarbital sodium anesthesia. After the animals were killed and bronchoalveolar lavages (BALs) were performed, the resulting fluid was subjected to differential centrifugation and determinations of proteins, phospholipids (PL), and disaturated phosphatidylcholine (DSPC). Pellet P1+2 was obtained by two centrifugations at 140 g; the supernatant was centrifuged at 1,000 g to obtain pellet P3 and subsequently at 60,000 g to obtain P4. Pellets P3 and P4 had the higher contents of PL and DSPC. Bivariate and multivariate correlational analyses indicate that 1) total PL in BAL was not related to any of the ventilatory variables studied, 2) PL in P3 and P4 fractions was directly correlated to the physiological range of variations in the frequency of large spontaneous gasps (fL), and 3) PL in P1+2 fraction was inversely related to fL. Cats subjected to bilateral section of carotid nerves, although presenting reduced chemosensory drive and ventilatory chemoreflexes, did not exhibit significant differences in resting ventilatory variables nor in alveolar surfactant components. Present results indicate that the total content of alveolar surfactant is not modified by ventilatory variations within physiological range but that the spontaneous occurrence of large gasps increases the proportion of more active forms of alveolar surfactant. This may mediate the role of augmented breaths in keeping lung compliance and preventing atelectasis under resting ventilatory conditions.

Animals↗
PubMed1989

[Effect of endotracheal instillation of hydrochloric acid on the contents of alveolar surfactant in rats].

Aspiration of gastric contents to the lung is a cause of Adult Respiration Distress syndrome. We studied the effects of endotracheal instillation of hydrochloric acid (2 ml/kg, 0.1 N solution) in anesthetized rats who were sacrificed 4 or 48 hr later. A control group received 0.9% saline solution instead. Total protein, phospholipids, disaturated phosphatidylcholine (DSPC) and number of cells were determined in the bronchoalveolar lavage fluid. Histologic studies were performed in one rat in each group. HCl caused edema and inflammatory reaction characterized by a rise in protein and cells in the bronchoalveolar fluid 48 hr after endotracheal instillation. This was associated with an increase in total phospholipid and in DSPC. Therefore, the inflammatory response to HCl is associated to an increase in alveolar surfactant 48 hr after instillation.

Animals↗