Effects of corticosteroids in preterm sheep on adaptation and sympathoadrenal mechanisms at birth

Stein, Howard; Oyama, Kotaro; Martinez, Alma M; Chappell, Barbara; Buhl, Eva Miriam; Blount, Leslie; Padbury, Jamés F.

doi:10.1152/ajpendo.1993.264.5.e763

Cited by 41 publications

(57 citation statements)

References 4 publications

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“…Studies on animals have shown evidence of the effect of corticosteroids on the mechanisms for adaptation to extrauterine life. Stein et al 66 demonstrated, on premature lambs, that corticosteroids led to an improvement in ventilatory, circulatory and metabolic functions of the animals treated, which was related to the increase in the adenyl-cyclase activity of the myocardium. Corticosteroids are also thought to promote an increase in the expression of adrenergic receptors in vessel walls and the myocardium, which assist in cardiocirculatory stabilization at birth.…”

Section: Resultsmentioning

confidence: 99%

“…In these circumstances, antenatal corticosteroids would also exercise a protective role in cardiorespiratory stabilization at birth 66 and their contribution towards successful adaptation to extra-uterine life would indirectly influence the frequency of respiratory distress syndrome, diminishing its occurrence. The incidence of intra-hospital death among patients who utilized antenatal corticosteroids and those who did not was also significantly lower in the treated group.…”

Section: Resultsmentioning

confidence: 99%

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Antenatal treatment with corticosteroids for preterm neonates: impact on the incidence of respiratory distress syndrome and intra-hospital mortality

et al. 2003

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CONTEXT: Although the benefits of antenatalcorticosteroids have been widely demonstrated in other countries, there are few studies among Brazilian newborn infants. OBJECTIVE:To evaluate the effectiveness of antenatal corticosteroids on the incidence of respiratory distress syndrome and intra-hospital mortality among neonates with a gestational age of less than 34 weeks. TYPE OF STUDY:Cross-sectional. SETTING:A tertiary-care hospital. PARTICIPANTS:Neonates exposed to any dose of antenatal corticosteroids for fetal maturation up to 7 days before delivery, and newborns paired by sex, birth weight, gestational age and time of birth that were not exposed to antenatal corticosteroids. The sample obtained consisted of 205 exposed newborns, 205 non-exposed and 39 newborns exposed to antenatal corticosteroids for whom it was not possible to find an unexposed pair. PROCEDURES:Analysis of maternal and newborn records. MAIN MEASUREMENTS:The primary clinical outcomes for the two groups were compared: the incidence of respiratory distress syndrome and intra-hospital mortality; as well as secondary outcomes related to neonatal morbidity. RESULTS:Antenatal corticosteroids reduced the occurrence of respiratory distress syndrome (OR: 0.33; 95% CI: 0.21-0.51) and the protective effect persisted when adjusted for weight, gestational age and the presence of asphyxia (adjusted OR: 0.27; 95% CI: 0.17-0.43). The protective effect could also be detected through the reduction in the need for and number of doses of exogenous surfactant utilized and the number of days of mechanical ventilation needed for the newborns exposed to antenatal corticosteroids. Their use also reduced the occurrence of intra-hospital deaths (OR: 0.51: 95% CI: 0.38-0.82). However, when adjusted for weight, gestational age, presence of prenatal asphyxia, respiratory distress syndrome, necrotizing enterocolitis and use of mechanical ventilation, the antenatal corticosteroids did not maintain the protective effect in relation to death. With regard to other outcomes, antenatal corticosteroids reduced the incidence of intraventricular hemorrhage grades III and IV (OR: 0.28; 95% CI: 0.10-0.77). CONCLUSIONS:Antenatal corticosteroids were effective in the reduction of morbidity and mortality among premature newborns in the population studied, and therefore their use should be stimulated within our environment.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Antenatal treatment with corticosteroids for preterm neonates: impact on the incidence of respiratory distress syndrome and intra-hospital mortality

et al. 2003

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“…The head and neck of the fetus were delivered through a midline abdominal incision and hysterotomy as described previously (3,4,9). Fetuses received an intr amuscular injection of ketamine (10 mg/kg) and acepromazine (0.1 mglkg).…”

Section: Methodsmentioning

confidence: 99%

“…All newborn lambs were managed as described previously in delivery protocols of chronically catheterized fetuses (3,4,9). Procedures included: insertion of an umbilical artery catheter for blood sampling and blood gas monitoring; administration of 10 mL/kg heparinized placental blood within 5 min of delivery to all animals; insertion of a left ventricular catheter via the right carotid artery during continuous measurement of left ventricular pressure, left ventricular dP/dt and the injection of microspheres; administration of 5% dextrose in water into the umbilical artery and left ventricular catheters at a total rate of 4.5 mLlkg/h throughout the study protocol.…”

Section: Methodsmentioning

confidence: 99%

Postnatal Cardiovascular and Metabolic Responses to a Single Intramuscular Dose of Betamethasone in Fetal Sheep Born Prematurely by Cesarean Section

et al. 1995

Pediatr Res

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Although the benefits of antenatal hormone treatment are well accepted, most studies have reported only pulmonary effects. There is evidence of beneficial cardiovascular and metabolic effects in studies using chronically catheterized animals; however because of the route of administration, the results are not directly applicable to clinical strategies. We previously demons trated sign ificant pulmonary effects in animals treated antenatally with a single, direct fetal, intramuscular injection of glucocorticoids . Th is study was performed to determine the effects of a single fetal injection of betamethasone (BETA) alone or in combination with thyroxine (T 4 ) on cardiovascular and metabolic respons es after preterm birth . Hemodynamic and metabolic response s at birth were determined in fetuses (126-d gestation; term = 150 d) treated with ultrasound-guided intramuscular injections of 0.5 mg/kg BETA (n = 7), BETA plus 60 g/kg T 4 (n = 7), or saline (SAL, n = 9). After 48 h, lambs were delivered by cesarean section and studied for 3 h. BETA treatment increased mean arterial blood pressure [56 ± 6 (SEM) versus 42 ± 3 mm Hg], heart rate (152 ± 5 versus 123 ± 4 beats/min), and cardiac Multiple studies have documented improved outcomes of preterm human infants born to mothers treated antenatally with glucocor ticoids. Most studies have focused primarily on pulmonary effects, although secondary outcome variables and retrospective metanalysis of clinical and other demographic data indicate beneficial effects in other organ systems (1, 2). Maternal corticosteroid treatment reduces nonrespiratory morbidities such as intraventricular hemorrhage, necrotizing enterocolitis, and patent ductus arteriosus. The mechanism(s) for these varied clinical outcomes is uncertain .In previous studies using chronically catheterized fetal sheep we demonstrated that antenatal corticosteroid infusion signifi- Responses of BETA + T 4 -treated animals were not different from animals treated with BETA alone. Glucose and FFA were simila r among all groups. The increase in catecholamine levels normally seen at birth was significantly attenuated in both the BETA and BETA + T 4 -treated animal s. A single, intramuscular injec tion of glucocorticoids 48 h before delive ry improves cardiovascular responses to preterm birth . This effect is not augmented by concomitant admi nistration of T4 ' (Pediatr Res 38: 709-715, 1995) Abbrev iations BETA, betamethasone T 4 , thyroxine T 3 , triiodothyronine SAL , saline TRH, thyrotropin-releasing hormone ANOVA, analysis of variance

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“…221). This therapy results in an increased ventilatory and cardiovascular response [294]. The effect is a decrease of morbidity [159], in spite of a brief period of suppression of the basal corticoid concentration.…”

Section: Therapeutic Effects Of Hormonesmentioning

confidence: 99%

The Pulmonary Surfactant System: Biochemical and Clinical Aspects

Creuwels

Golde

Haagsman

1997

Lung

283

188

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Abstract. This article starts with a brief account of the history of research on pulmonary surfactant. We will then discuss the morphological aspects and composition of the pulmonary surfactant system. We describe the hydrophilic surfactant proteins A and D and the hydrophobic surfactant proteins B and C, with focus on the crucial roles of these proteins in the dynamics, metabolism, and functions of pulmonary surfactant. Next we discuss the major disorders of the surfactant system. The final part of the review will be focused on the potentials and complications of surfactant therapy in the treatment of some of these disorders. It is our belief that increased knowledge of the surfactant system and its functions will lead to a more optimal composition of the exogenous surfactants and, perhaps, widen their applicability to treatment of surfactant disorders other than neonatal respiratory distress syndrome.Key words: Surfactant protein-Pulmonary surfactant-Respiratory distress syndrome. HistoryResearch on surfactant goes back to 1929 when von Neergaard published the first paper about the difference in pressure needed to inflate lungs with air or with liquid [333]. He found that the pressure necessary for filling the lungs with air was higher than when the lungs were filled with liquid. To explain this result he stated that the alveoli were stabilized by lowering the naturally high surface tension of the air/water interface. In 1946 Thannhauser and co-workers reported that lung tissue has a remarkably high content of the lipid dipalmityl lecithin (current name, dipalmitoylphosphatidylcholine)Offprint requests to: Henk P. Haagsman.

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Effects of corticosteroids in preterm sheep on adaptation and sympathoadrenal mechanisms at birth

Cited by 41 publications

References 4 publications

Antenatal treatment with corticosteroids for preterm neonates: impact on the incidence of respiratory distress syndrome and intra-hospital mortality

Antenatal treatment with corticosteroids for preterm neonates: impact on the incidence of respiratory distress syndrome and intra-hospital mortality

Postnatal Cardiovascular and Metabolic Responses to a Single Intramuscular Dose of Betamethasone in Fetal Sheep Born Prematurely by Cesarean Section

The Pulmonary Surfactant System: Biochemical and Clinical Aspects

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