CDPdiacylglycerol pyrophosphatase (E.C. 3.6.1.26) activity has been examined in rat lung mitochondrial and microsomal fractions. While the mitochondrial hydrolase exhibited a broad pH optimum from pH 6-8, the microsomal activity decreased rapidly above pH 6.5. Apparent Km values of 36.2 and 23.6 microM and Vmax values of 311 and 197 pmol.min-1.mg protein-1 were observed for the mitochondrial and microsomal preparations, respectively. Addition of parachloromercuriphenylsulphonic acid led to a marked inhibition of the microsomal fraction but slightly stimulated the mitochondrial activity at low concentrations. Mercuric ions were inhibitory with both fractions. Although biosynthetic reactions utilizing CDPdiacylglycerol require divalent cations, addition of Mg2+, Mn2+, Ca2+, Zn2+, Co2+, and Cu2+ all inhibited the catabolic CDPdiacylglycerol hydrolase activity in both fractions. EDTA and EGTA also produced an inhibitory effect, especially with the mitochondrial fraction. Although addition of either adenine or cytidine nucleotides led to a decrease in activity with both fractions, the marked susceptibility to AMP previously reported for this enzyme in Escherichia coli membranes, guinea pig brain lysosomes, and pig liver mitochondria was not observed. These results indicate that rat lung mitochondria and microsomes contain specific CDPdiacylglycerol hydrolase activities, which could influence the rate of formation of phosphatidylinositol and phosphatidylglycerol for pulmonary surfactant.

We reported previously that metyrapone inhibited the maturational effect of adrenocorticotropin in the fetal sheep lung, even in the presence of exogenous glucocorticoids. To examine the role of β-adrenergic input in this response we examined lung maturation in fetal sheep treated for 100 hours in vivo with adrenocorticotropin (66 ng/min for 15 minutes every 2 hours, n = 5); adrenocorticotropin plus propranolol (40 μg/min, n = 4), or saline solution (n = 8). Pulmonary maturation was assessed by pressure-volume curves, phospholipid content, and morphologic features. The basal cortisol level rose from <5 to 82.0 ± 12.1 and 83.5 ± 8.0 ng/ml in the adrenocorticotropin and adrenocorticotropin plus propranolol groups, respectively. The adrenal: body weight ratio (× 10−4) rose from 1.43 ± 0.12 in the saline solution group to 2.90 ± 0.16 and 2.51 ± 0.14 in the adrenocorticotropin and adrenocorticotropin plus propranolol groups, respectively. Lung distensibility (milliliters of air per gram of lung) rose from 1.10 ± 0.14 to 1.90 ± 0.20 in the adrenocorticotropin group but was unchanged (0.98 ± 0.24) in the adrenocorticotropin plus propranolol group. Phosphatidylcholine (milligrams per gram of lung) in the lung lavage rose from 0.07 ± 0.02 to 0.23 ± 0.11 in the adrenocorticotropin group but was not significantly changed (0.12 ± 0.06) in the adrenocorticotropin plus propranolol group. We conclude that propranolol inhibits the maturational effects of adrenocorticotropin on the fetal lung, which implies that the mechanism of pulmonary maturation is not solely dependent on endogenous cortisol and must be mediated, at least in part, through adrenergic responses.

The mammalian lung is stabilized by a specialized material, the pulmonary surfactant, which acts by reversibly reducing the surface tension at the air-liquid interface of the lung during breathing. Pulmonary surfactant contains approximately 90% lipid and 10% proteins. Dipalmitoyl phosphatidylcholine, the major lipid component, appears to be primarily responsible for the ability to reduce surface tension to near 0 dyn/cm (1 dyn = 10 microN). The other components of pulmonary surfactant promote the adsorption and spreading of this disaturated lecithin at the air-liquid interface. Surfactant activity can be accessed by physical and biological assays. Apparent discrepancies between the results obtained with the Wilhelmy plate surface balance and the pulsating bubble surfactometer have led to the suggestion that separate "protein-facilitated" (catalytic type) and "protein-mediated" (chemical type) processes may be involved in adsorption and (or) spreading at the different surfactant concentrations used with these two techniques. Artificial surfactants, which mimic the essential properties of the natural product with the pulsating bubble surfactometer, can be produced with synthetic lipids. Treatment of prematurely delivered infants suffering from the neonatal respiratory distress syndrome with lipid extracts of pulmonary surfactant leads to a marked improvement in gaseous exchange.

Bovine pulmonary surfactant was obtained by endotracheal lavage of lungs from newly slaughtered cows followed by differential centrifugation. Lipid extracts of bovine surfactant contained 3% neutral lipid, mainly as cholesterol and diacylglycerol and 97% phospholipid. Phosphatidylcholine (79%) and phosphatidylglycerol (11%) accounted for most of the phospholipids with smaller amounts of phosphatidylethanolamine, phosphatidylinositol, lyso-bis-phosphatidic acid and sphingomyelin. Fatty acid analysis revealed high levels of palmitate in phosphatidylcholine and to a lesser extent phosphatidylglycerol, but not in the other diacylphospholipids. Phosphatidylcholine was 53% disaturated and phosphatidylglycerol was 23% disaturated. Monoenoic species accounted for the major proportion of the remaining lipid. The protein content was 10% as estimated by the Lowry procedure and 5% when determined by amino acid analysis. Extraction with chloroform/methanol removed ca. 90% of the protein but had no effect on the surfactant properties as evaluated by a pulsating bubble technique.

The role of Adrenocorticotrophin (ACTH), administered in physiological doses (12 micrograms/d), on lung maturation was investigated in the intact ovine fetus at 127-130 days of gestation. ACTH1-24 was administered in a pulsatile or continuous dose for 72 hours. Compared to untreated twins (n = 4) and saline infused fetuses (n = 4), the lungs of the pulsatile-ACTH (n = 10) and continuous-ACTH (n = 4) treated fetuses showed accelerated prepartum maturation by all indices used. Lung distensibility (V40-ml of air per g of wet lung at 40 cm H2O pressure), as determined by pressure-volume curves with air was 1.62 +/- 0.18 vs 0.72 +/- 0.23 and 0.66 +/- 0.12 while the stability (Vo-ml of air per g of wet lung at atmospheric pressure) was 0.33 +/- 0.07 vs 0.10 +/- 0.01 and 0.21 +/- 0.09 for the P-ACTH group vs the control groups (P less than 0.005). In the continuous-ACTH group vs their untreated twins the distensibility was 1.58 +/- 0.10 vs 0.56 +/- 0.11 while the stability was 0.83 +/- 0.20 vs 0.09 +/- 0.01 respectively (less than 0.005). Phosphotidylcholine concentration in lavage fluid increased from 0.05 +/- 0.02 mg/g of lung to 0.24 +/- 0.07 in the pulsed-ACTH group compared to untreated twin fetuses (P less than 0.05). Morphologically the lungs of the treated groups were well aerated with thin walled airsacs. In both treated groups, there was a doubling of the adrenal weight (P less than 0.005). Fetal plasma cortisol basal level increased from less than 5 ng/ml to 143.5 +/- 66.5 ng/ml in the continuous-ACTH group while it only rose to 36.6 +/- 7.5 ng/ml in the pulsed-ACTH group by 72 hours. Superimposed on the rise in basal fetal cortisol, there was an acute increase in cortisol temporally related to each ACTH pulse; the peaks reaching levels indistinguishable from the levels of the continuous-ACTH infusion. It is concluded that the administration of low doses of ACTH markedly accelerate prepartum maturation of the intact ovine lung over 72 hours. The mechanism by which ACTH exerts this powerful maturation effect on the fetal lung remains to be elucidated.

Morphological features of 3rd order, fetal stem arteries of placentae from 50 'toxemic' patients, including all types, i.e., those with pre-eclampsia, essential hypertension, and chronic renal disease, were compared with similar arteries in 50 placentae of normal pregnancies. Striking changes of the arterial wall and subtle but definite alterations in the surrounding stroma were observed in the fetal arteries from hypertensive pregnancies. The earliest mural alteration consisted of endothelial proliferation which narrowed the lumen. This was followed by proliferation of subendothelial and smooth muscle cells probably derived from the medial layer. In the media, the proliferating smooth muscle cells were affected by vacuolation and other degenerative processes. Of the above changes the intimal and medial alterations were present in 38 placentae of toxemic patients, whereas some of these features were found only in 6 cases of the control group. Other lesions of the fetal stem arteries (i.e. thrombi and arteritis) were observed less commonly. Moreover, smooth muscle cells that usually are scattered in the villous stroma in normal placentae, in toxemic patients were more numerous and tended to form bridges between the fetal arteries. On the basis of the present observations, it may be concluded that several lumen-narrowing alterations affect the fetal arteries of the placentae in toxemia of pregnancy. Whereas these undoubtedly contribute to the 'placental insufficiency' commonly found in this group of diseases, they probably represent a reaction to a more basic and as yet not identified factor(s) that may be operational in 'toxemia' of pregnancy.

Assessment of 180 high risk newborns revealed significant impairment of the neurological status compared to the control group; the degree of impairment was related to the number and severity of the adverse factors. In addition to the perinatal factors, prenatal factors were also related to the low neurological score. In the high risk group, the chief neurologic pathology evidenced as poor muscle tone in the term infants and poor vigilance in the preterm infants. The neurological score showed better correlation to the arterial pH and base status as compared to the oxygen content. The adverse effect of hypoxia was more persistent in the term infants than in the preterm infants. The bilirubin level of 8 to 15 mg/dl did not significantly influence the neurological status of the newborns. Some high risk infants with normal Apgar score had significantly low neurological score even on the fourth day after birth, compared to the control group.

A program designed to achieve normal plasma glucose concentrations before meals was tested in 83 insulin-dependent diabetic women during 110 pregnancies. The women rigidly controlled their carbohydrate intake but not their total energy intake, and twice daily they injected a combination of short-acting (Toronto) and intermediate-acting (NPH or Lente) insulin. Obstetric care was highly individualized and was aimed at avoiding or minimizing the impact of complications, such as hypertension, on the fetus and ensuring fetal lung maturity before delivery. The mean plasma glucose levels before meals (+/- standard error of the mean) were 136 +/- 9, 117 +/- 5 and 101 +/- 2 mg/dl during the first, second and third trimesters respectively. Obstetric complications included hypertensive disease of pregnancy (in 30.0%) and hydramnios (in 16.4%). The mean gestational age (+/- standard deviation [SD]) was 38.1 +/- 1.8 weeks, the cesarean section rate 45.4% and the mean stay in hospital for diabetes control before delivery (+/- SD) 15.7 +/- 9.6 days. The perinatal mortality rate was 0.9%. Neonatal problems included congenital anomalies in 3.6%, somatomegaly in 24.6%, hypoglycemia in 26.5%, hypocalcemia in 17.3% and hyperbilirubinemia in 39.4%. There were nine cases (8.2%) of the respiratory distress syndrome, four (3.6%) of which were severe. These findings lend support to the importance of a policy aimed at achieving normoglycemia and fetal lung maturity before delivery, goals that are attainable without lengthy antenatal hospitalization.

A comparative study on gestational age assessment of 155 newborn infants was undertaken using a scoring system with the clinical criteria: (1) criteria of Dubowitz et al, (2) external criteria alone, and (3) primitive reflexes in relation to the amniotic fluid study. The effect of certain prenatal and perinatal abnormal states on the results of these methods was evaluated. The criteria of Dubowitz et al, external criteria and amniotic fluid studv showed greater accuracy than the primitive reflexes for the assessment of gestational age of normal infants, especially the preterm group. In asphyxiated babies and in babies of diabetic mothers, the neurological score, being poor, under-estimated the gestational age. The amniotic fluid score and the external criteria were more helpful than the neurological score for the assessment of gestational age in these states. Smoking and toxemia did not influence the score by any of the methods in normal infants. In dysmaturity, the amniotic fluid score and score by primitive reflexes were more reliable than the external criteria alone and the criteria of Dubowitz et al. In general, the amniotic fluid score was not influenced by abnormal states compared to scores by other methods.

Study of 108 samples of amniotic fluid obtained between 28 and 42 weeks' gestation from 101 patients revealed that in normal pregnancies the creatinine concentration, lecithin/sphingomyelin (L/S) ratio and percentage of fat cells correlated better with the gestational age of the newborn--assessed by clinical criteria--than did the bilirubin and sodium concentrations. A creatinine concentration of 1.75 mg/dL or more, an L/S ratio of 4 or more and a fat cell percentage of 10 or more correlated significantly with a gestational age of 37 weeks or more. In abnormal pregnancies (those with obstetric or medical complications, or both) the mean creatinine concentration in the amniotic fluid was significantly less than expected for gestational age in fetal dysmaturity and greater than expected when the mother had diabetes. The mean L/S ratio in the amniotic fluid was elevated when the mother had hypertension or smoked and in cases of fetal dysmaturity or long interval between rupture of the membranes and delivery, whereas it was significantly lower than normal when the mother had diabetes. The mean bilirubin concentration in the amniotic fluid was significantly lower than normal when the mother had hypertension. When the mother had diabetes, maturity of the fetal lung, liver, skin and brain appeared to be delayed, according to the values for the amniotic fluid constituents.

Uterine smooth muscle cells in "toxemia of pregnancy" contain varying amounts of fat—a feature to date believed to characterize only the arterial smooth muscle cells in atherosclerotic lesions. Thus, the smooth muscle cells at these two sites do not differ essentially in their reactivity to certain forms of injury: hypoxia may represent an injurious factor common to both "toxemia" and atherosclerosis. These observations imply that the view that the arterial smooth muscle cells are biologically different than are those elsewhere may no longer be tenable.

Uterine smooth muscle cells in "toxemia of pregnancy" contain varying amounts of fat—a feature to date believed to characterize only the arterial smooth muscle cells in atherosclerotic lesions. Thus, the smooth muscle cells at these two sites do not differ essentially in their reactivity to certain forms of injury: hypoxia may represent an injurious factor common to both "toxemia" and atherosclerosis. These observations imply that the view that the arterial smooth muscle cells are biologically different than are those elsewhere may no longer be tenable.

The variation in the neonatal mortality rate from 39.6/1,000 to 16.43/1,000 live births in a series of 913 high-risk pregnancy cases manged in a Regional Obstetrical Neonatal Intensive Care Unit over the past 5 years has been dependent on a man, not a machine. The presence of a trained full-time director of the obstetric part of the team was an unexpected variable which seems significant. A follow-up of 300 survivors at 3 years of age with the Denver development screening test (DDST) and the Stanford-Binet test (S-B) has been completed. Intensive antenatal and immediate postnatal care by an obstetric-pediatric team reduced the sequela of physical or mental retardation to 3 per cent (DDST) and 11.6 per cent (S-B).