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Biomedical subjects

R D Leake

Publications and source records attributed to R D Leake.

103 records · Page 6Linked to original sources
PubMed1976

Inulin clearance in the newborn infant: relationship to gestational and postnatal age.

Thirty-eight healthy newborn infants with gestational ages ranging from 25 to 42 weeks were studied at 2 days to 9 weeks postnatal age to evaluate the rate of glomerular maturation after birth. Glomerular function was assessed by a constant infusion method for inulin clearance (Cin). Cin was nearly identical when measured by the traditional clearance method and by the constant infusion technique. The Cin of 22 infants 2-3 days old ranged from 0.6 to 17.9 ml/min and was directly related to gestational age (r = 0.81, P less than 0.001). For 26 infants studied at 1-9 weeks of age, Cin was directly proportional to conceptual (gestational and postnatal) age (r = 0.89, P less than 0.001), and approximated that of infants of similar gestational age studied at 2-3 days of age.

Aging↗
PubMed1975

Hyperviscosity syndrome associated with necrotizing enterocolitis.

Hyperviscosity, or decreased fluidity secondary to increased numbers of red blood cells, leads to tissue hypoperfusion. We report the case of an infant with hyperviscosity who died from necrotizing enterocolitis (NEC), and describe the presumptive association between NCE and hyperviscosity.

Adult↗
PubMedDate not supplied

Fetal lung fluid response to maternal hyperosmolality.

Lung fluid production in utero, a significant source of amniotic fluid, may be regulated by the fetus in response to environmental stress. We monitored changes of maternal and fetal plasma osmolality, plasma arginine vasopressin level, and fetal lung fluid production in response to mannitol-induced change in maternal osmolality in five chronically catheterized ovine fetuses. Four additional ewes and their fetuses did not receive mannitol and served as controls. Maternal infusion of 20% mannitol resulted in maternal and subsequent fetal hyperosmolality (changing from 303 +/- 2 to 322 +/- 2 mOsm and 300 +/- 5 to 319 +/- 8 mOsm, respectively), Mean fetal lung fluid production significantly decreased (from 2.6 +/- 0.4 to 1.6 +/- 0.4 ml/10 min), whereas lung fluid osmolality significantly increased (from 298 +/- 2 to 303 +/- 3 mOsm) in the study animals. No changes in lung fluid sodium or potassium concentrations were observed in study or control fetuses. Fetal plasma arginine vasopressin level significantly increased in the study fetuses (2.2 +/- 0.3 to 5.3 +/- 1.6 microU/ml), though not in control animals. These results indicate that the fetal lamb responds to increased osmolality by decreasing lung fluid production, and that there is a concomitant increase in lung fluid osmolality. This response appears to be mediated via increased fetal plasma vasopressin levels.

Animals↗
PubMedDate not supplied

Postnatal thyroxine supplementation in infants less than 32 weeks' gestation: effects on pulmonary morbidity.

OBJECTIVE: Transient hypothyroxinemia in premature newborns has been linked with poor neonatal outcomes. We designed this study to evaluate the effects of early thyroxine (T4) administration in the premature infant. STUDY DESIGN: A total of 49 newborns less than 32 weeks' gestation, were randomized in a double-blind, placebo-controlled trial. Within the first 48 hours of life, T4 (10 or 20 micrograms/kg; intravenous or through nasogastric tube, respectively) was administered for a total of 21 days. Chronic lung disease, the primary outcome variable, was defined by oxygen dependency at 28 days of life. RESULTS: The incidence of chronic lung disease, death, grade III or IV intraventricular hemorrhage, periventricular leukomalacia, and sepsis was not different in the placebo and treated groups. CONCLUSION: Early T4 supplementation in preterm newborns less than 32 weeks' gestation does not decrease the incidence of chronic lung disease or other complications of prematurity.

Bronchopulmonary Dysplasia↗