| dc.contributor.author | MacKenzie, Mary-Gordon. | en_US |
| dc.date.accessioned | 2014-10-21T12:37:47Z | |
| dc.date.available | 1993 | |
| dc.date.issued | 1993 | en_US |
| dc.identifier.other | AAINN87473 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55359 | |
| dc.description | One of the leading causes of mortality and morbidity in the neonate is respiratory distress syndrome (RDS). RDS occurs due to a deficiency of surfactant in the alveoli of the premature infant at birth. Glucocorticoids have been shown to be effective in decreasing the incidence of RDS when administered prenatally. Their action is to increase the production of surfactant in the immature lung. Unfortunately glucocorticoids have been found to be effective only under ideal circumstances (i.e. dependent on the dose, species, route of administration, and the time and length of exposure to these steriods). Hence investigators have attempted to find other agents which can act alone or synergistically with glucocorticoids to increase fetal lung maturation in the premature fetus. | en_US |
| dc.description | The specific goal of these studies was to examine the effects of the glucocorticoid cortisol, given in combination with either isoxsuprine or thyrotropin releasing hormone (TRH) on fetal lung maturation. We were also interested in the individual effects of isoxsuprine and TRH on the surfactant pools. Our results indicate that a combination of glucocorticoids and isoxsuprine, administered either simultaneously or sequentially, produced no further increase in the surfactant pools above the effect of the steroid alone. In vivo experiments examining the effects of short term exposure to isoxsuprine alone have shown that this agonist may produce an inhibitory phase in surfactant secretion which is dependent on the gestational age of the fetus or newborn pup. In vitro experiments showed a stimulation of both synthesis and secretion of disaturated phosphatidylcholine (DSPC) from the alveolar type II cell treated with isoxsuprine. All combinations of glucocorticoids and TRH resulted in an increased production of surfactant over either drug given alone and the response was maximal with multiple doses of TRH. Our results indicate that the effectiveness of glucocorticoids, either alone or in combination with other agents such as TRH or isoxsuprine, is dependent on gestational age at the time of treatment and duration of prenatal drug exposure. | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 1993. | en_US |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | | en_US |
| dc.subject | Health Sciences, Pharmacology. | en_US |
| dc.subject | Biology, Animal Physiology. | en_US |
| dc.title | The effects of glucocorticoids and other agents on fetal lung maturation. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
