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Biomedical subjects

D L Phelps

Publications and source records attributed to D L Phelps.

90 records · Page 5Linked to original sources
PubMed1981

Plasma tocopherol levels in term infants fed breast milk or proprietary formulae.

Plasma tocopherol levels were compared at 2 days and 2 weeks in 27 normal term infants fed breast milk or one of two proprietary formulae. Levels rose from cord values of approximately 0.6 to 1 mg/dl at 2 days and 1.6 mg/dl at 2 weeks. There were no significant differences between the three groups. Current levels of tocopherol supplementation in infant formulae result in plasma levels comparable to those achieved with breast milk in healthy term infants.

Aging↗
PubMed1979

Vitamin E in kitten oxygen-induced retinopathy. II. Blockage of vitreal neovascularization.

The effect of vitamin E (tocopherol) on oxygen-induced retinopathy was studied in the kitten after a quantitative scoring system was developed for their India ink injected retinal flat preparations. In 75 previously described kittens exposed to two or three days of oxygen from day 3, treatment from day 1 with vitamin E or placebo disclosed that kittens treated with vitamin E had less retinopathy. Theories of the mechanism of action of vitamin E would predict that, if given only after the oxygen exposure, vitamin E should be ineffective. This was tested in 37 kittens with placebo or drug begun only after withdrawal from oxygen. Unexpectedly, significantly less intravitreal neovascularization was found in kittens treated with vitamin E after oxygen exposure.

Animals↗
PubMed1979

Observations of vitamin E in experimental oxygen-induced retinopathy.

Retrolental fibroplasia (RLF) is a proliferative retinopathy observed in premature infants. Its relationship to oxygen has led to both clinical and laboratory research into the potential benefits of the antioxidant tocopherol in this disorder. Although the clinical trials to date have only suggested a beneficial result, studies in the kitten model demonstrate two significant actions of tocopherol in protecting against this retinopathy, only one of which is predicted by theory. These data support the need for prospective controlled trials in human premature infants.

Animals↗
PubMed1978

Effects of cortisol and aminophylline upon survival, pulmonary mechanics, and secreted phosphatidyl choline of prematurely delivered rabbits.

Rabbits delivered at 27.0 days of gestation were studied after administration of cortisol (2 mg/kg/day), aminophylline (6.25 mg/kg/day), or sterile saline to the does on days 24-26 of gestation. Survival at 60 min was 52.9% in the aminophylline-treated group and 22.2% in the control and cortisol-treated groups with all animals being in a warm, oxygen-enriched environment and receiving frequent tactile stimulation. Lung volume at 30 cm H2O was lower in the cortisol-treated group than in the controls or aminophylline-treated group in animals surviving for 60 min (Table 2). The aminophylline-treated group retained significantly more gas at low pressures on the deflation curve (Table 2) and had significantly more phosphatidylcholine recovered in lung lavage fluid (Table 3) than the other groups. Aminophylline appears to have enhanced lung maturation better than cortisol in this experimental model.

Adenosine Monophosphate↗
PubMed1977

Spironolactone: relationship between concentrations of dethioacetylated metabolite in human serum and milk.

The concentration of canrenone, a principal metabolite of spironolactone, was determined in human serum and milk. The milk to serum concentration ratios of this metabolite were 0.72 at 2 hr and 0.51 at 14.5 hr after ingestation of spironolactone. It was estimated that the maximum quantity of canrenone ingested daily by a human infant via its mother's milk would be approximately 0.2% of the daily dose of spironolactone given to the mother.

Adult↗
PubMed1977

The role of tocopherol in oxygen-induced retinopathy: kitten model.

The effect of tocopherol (vitamin E) on oxygen-induced retinopathy was studied in 75 kittens following the development of a 12-point scoring system to quantitate the degree of retinopathy seen at three weeks. The tocopherol was found to be beneficial when given daily from the day of birth (P less than .0001) with oxygen exposures of two to three days (79% FiO2) beginning on day 3. Caution is urged in applying these data to humans because (1) hepatosplenomegaly was noted in the treated animals, and (2) the kitten model for oxygen-induced retinopathy is not entirely satisfactory, Pediatrics, 59:998-1005 1977, RETROLENTAL FIBROPLASIA, OXYGEN TOXICITY, VITAMIN E, RETINOPATHY, KITTEN.

Animals↗
PubMed1976

PAH clearance, sodium excretion, and PAH extraction ratio in acidotic near-term lambs treated with hypertonic sodium bicarbonate.

The electrolyte changes and renal hemodynamic adjustment to hypertonic sodium bicarbonate (NaHCO3) correction of a metabolic acidosis were studied in 4 neonatal lambs and in 2 controls. PAH clearance increased from 0.92 to 1.65 ml/min/kg (p less than 0.05), urine flow from 0.37 to 0.61 ml/min/kg (p less than 0.05), and Na excretion from 8.4 to 23.7 muEq/min/kg (p less than 0.05) during the NaHCO3 infusion. These increases were transient and returned to pre-infusion levels following NaHCO3 infusion. Calculation of Na intake and output revealed a net retention of 5.1 mEq/kg in the study lambs which was reflected in a rise of serum Na and osmolarity (Osm) during the post-NaHCO3 -infusion period. The extraction ratio of sodium p-aminohippurate (EPAH) and its relationship to arterial pH were studied in 4 additional lambs. The EPAH did not change with metabolic acidosis but for unknown reasons, the infusion of NaHCO3 resulted in a temporary depression of EPAH (p less than 0.001).

Acidosis↗
PubMed1975

Placenta to lamb fetus transfusion in utero during acute hypoxia.

Maternal and fetal hemodynamics, placental blood flow, fetal-placental blood volume, placental blood volume, and fetal blood volumes were measured in six chronic sheep prepartions to evaluate their changes during acute fetal hypoxia induced by maternal hypoxia. During fetal hypoxia, the maternal and fetal arterial blood pressure and heart rate were essentially unchanged. The placental blood flow (control equal to 325 ml.per kilogram per minute) was also unchanged during the hypoxia period. However, the placental blood volume decreased significantly from 65 to 60 and 51 ml. per kilogram at 15 and 30 minutes of hypoxia period, respectively. The fetal blood volume increased reciprocally and significantly from 86 to 109 and 102 ml. per kilogram at the same periods of hypoxia since the fetal-placental blood volumes were unchanged. These blood volume changes persisted for 30 to 60 minutes following the stoppage of hypoxia experiments. The placental vascular resistance measured in six experiments showed a significant increment during hypoxia, suggesting placental vasoconstriction as the responsible mechanism for the reduction of placental blood volume and reciprocal increase in fetal blood volume. The data suggest that significant placental transfusion to the lamb fetus may occur in utero during fetal hypoxia resulting in a higher fetal blood volume before birth.

Acute Disease↗
PubMedDate not supplied

Cryotherapy in infants with retinopathy of prematurity. A decision model for treating one or both eyes.

Formal decision model analysis for cryotherapy to reduce blindness from retinopathy of prematurity shows that the decision to treat depends substantially on disease severity, the probability of long-term side effects, and correlations of treatment outcomes and side effects for individuals in whom both eyes are treated. The model indicates that both eyes should be treated regardless of disease severity only when the probability of long-term side effects is zero. As risk of long-term side effects increase, treating neither eye or only the worst eye is preferred for an increasingly large spectrum of disease. With high correlations of long-term side effects, treating the worst eye is preferred for moderate levels of disease severity. For high disease severity, treating both eyes is recommended, even when the probability of long-term side effects is high. Better-informed treatment recommendations must await new data to assess risks of long-term side effects and correlations of treatment outcomes and side effects.

Cryosurgery↗
PubMedDate not supplied

A semipermeable skin dressing for extremely low birth weight infants.

Skin breakdown and high fluid requirements are common problems in extremely low birth weight infants that may be reduced by application of a semipermeable skin dressing (SPD). An SPD was applied to 39 study infants who weighed < 1000 gm (control subjects, n = 37) to determine whether it would protect the skin and decrease fluid requirements. Randomization occurred before 12 hours of life and SPD was applied to the chest, abdomen, and back. Sixty-one infants survived the first 14 days. Skin remained nonerythematous, intact, and undamaged under the dressing, whereas uncovered skin sustained significant breakdown in both groups. No significant differences were found in fluid or electrolyte status. Although the SPD did not affect fluid requirements, the significant improvement in skin integrity under the SPD may justify its use in premature infants with delicate skin.

Bandages↗