Vitamin E alters alveolar type II cell phospholipid synthesis in oxygen and air.

Newborn rats were injected with vitamin E or placebo daily until 6 days after birth. The effect of vitamin E pretreatment on in vitro surfactant phospholipid synthesis was examined in isolated type II cells exposed to oxygen or air form 24 h in vitro. Type II cells were also isolated from untreated 6-day-old rats and cultured for 24 h in oxygen or air with control medium or vitamin E supplemented medium. These cells were used to examine the effect of vitamin E exposure in vitro on type II cell phospholipid synthesis and ultrastructure. Phosphatidylcholine (PC) synthesis was reduced in cells cultured in oxygen as compared with air. This decrease was not prevented by in vivo pretreatment or in vitro supplementation with vitamin E. Vitamin E pretreatment increased the ratio of disaturated PC to total PC and increased phosphatidylglycerol synthesis. The volume density of lamellar bodies in type II cells was increased in cells maintained in oxygen. Vitamin E did not affect the volume density of lamellar bodies. We conclude that in vitro hyperoxia inhibits alveolar type II cell phosphatidylcholine synthesis without decreasing lamellar body volume density and that supplemental vitamin E does not prevent hyperoxia-induced decrease in phosphatidylcholine synthesis.

A comparison of fluorescent and nonfluorescent light sources for phototherapy.

We have compared fluorescent and nonfluorescent light sources for phototherapy for newborn infants with hyperbilirubinemia. Phototherapy was provided by a tungsten halogen lamp and conventional fluorescent light with identical radiant flux of 6 microW/sq cm. For 22 infants treated with the nonfluorescent lamp the mean duration of phototherapy was 33.77 hours and the mean reduction of bilirubin was 3.84 mg/100 ml/day. This did not differ significantly from infants treated with conventional fluorescent lights. The nonfluorescent light can be utilized for infants in incubators or on radiant warmers. These results provide additional support for the relationship between radiant flux as a practical measure of phototherapy dose and the clinical response of a reduction in serum bilirubin.

Amelioration of bronchopulmonary dysplasia after vitamin E administration. A preliminary report.

We studied the effect of vitamin E on the development of bronchopulmonary dysplasis in neonates with respiratory-distress syndrome. Twenty infants received vitamin E administered intramuscularly during the acute phase of the syndrome, and 20 infants served as controls. Administration of vitamin E significantly increased the serum vitamin E concentration. Nine vitamin-treated and 13 control patients required supplemental oxygen for longer than 250 hours; all were treated with positive-pressure ventilation and endotracheal continuous distending airway pressure. Six of those 13 controls had x-ray changes consistent with bronchopulmonary dysplasia, and four died. None of the nine vitamin-treated patients had changes characteristic of bronchopulmonary dysplasia (P = 0.046), and all survived. Administration of vitamin E during the acute phase of the respiratory-distress syndrome appears to modify the development of bronchopulmonary dysplasis.

Importance of radiant flux in the treatment of hyperbilirubinemia: failure of overhead phototherapy units in intensive care units.

Prior to 1972, radiation used to treat neonatal hyperbilirubinemia was based upon the photometric unit, the foot-candle, a measure of light illumination. Measurements in terms of microwatts per square centimeter for selective wavelengths is more precise. We compared the effectiveness of phototherapy provided by overhead phototherapy units in intensive care modules vs. conventional phototherapy units. Forty-two infants were studied over a six-month period and divided into three groups based upon radiant flux measurements as follows: Group 1 (No. = 6), 1.0 muw to 1.9 muw/sq cm/nm; group 2 (No. = 15), 2.0 muw to 3.9 muw/sq cm/nm; group 3 (No. = 21), 4.0 muw to 6.0 muw/sq cm/nm. All flux determinations were made within the 400- to 500-nm range. All infants in group 1 were treated with overhead phototherapy units in the intensive care modules. Because of multiple factors known to increase the risk of kernicterus, evaluation of effectiveness of phototherapy at low radiant flux was limited in group 1. Significant changes in bilirubin were noted by 48 hours when comparing group 3 with groups 1 and 2. A minimum of 4.0 muw/sq cm/nm appears necessary for effective phototherapy. As designed, phototherapy units in intensive care modules are ineffective in delivering this therapeutic level of radiant flux.