Impaired glucocorticoid synthesis in premature infants developing chronic lung disease

Premature infants have higher cortisol precursor concentrations than term infants; however, many sick preterm infants have surprisingly low cortisol concentrations. Those who develop chronic lung disease (CLD) have lower cortisol values than those who recover. We hypothesized that some infants have a decreased ability to synthesize cortisol, leading to physiologic disruptions including amplified inflammatory responses, thereby resulting in CLD. We measured cortisol, 11-deoxycortisol, 17-hydroxyprogesterone, 17-hydroxypregnenolone, dehydroepiandrosterone sulfate, and ACTH in 40 extremely low birth weight infants enrolled in a study of low-dose hydrocortisone therapy to prevent CLD. Thirty-four infants survived and 15 developed CLD. Hydrocortisone therapy did not suppress ACTH or any measured steroid value. Before study (<48 h of life), 17-OH progesterone was higher in CLD infants, as was the ratio of 17-OH progesterone to 11-deoxycortisol. On d 15-19 (> or =72 h after end of therapy), basal and stimulated cortisol concentrations were lower in CLD infants. In contrast, the basal ratio of 11-deoxycortisol to cortisol was higher in CLD infants, as were stimulated values of 17-OH progesterone and stimulated ratios of 17-OH progesterone to 11-deoxycortisol and 11-deoxycortisol to cortisol. Thus, infants who developed CLD had lower basal and stimulated cortisol values, but elevated cortisol precursors and precursor to product ratios, compared with infants who recovered. These data support the hypothesis that these immature infants have a decreased capacity to synthesize cortisol, which may lead to a relative adrenal insufficiency in the face of significant illness.

Effect of single versus multiple courses of antenatal corticosteroids on maternal and neonatal outcome

OBJECTIVE

Treatment of pregnant mothers with a single course of antenatal corticosteroids significantly reduces neonatal mortality and morbidity. Multiple weekly courses are often given. However, the safety and efficacy of repeated courses of antenatal corticosteroids have not been adequately studied.

STUDY DESIGN

A retrospective study was performed for 609 mothers and their 713 infants who were treated with 1 to 12 courses of antenatal corticosteroids. Data for 369 singleton preterm infants born at < or =34 weeks' gestation, 210 multiple gestations, and 134 infants delivered at > or =35 weeks' gestation were analyzed separately.

RESULTS

The incidence of respiratory distress syndrome was 45% for single-course and 35% for multiple-course groups (P =.005; odds ratio, 0.44; 95% confidence interval, 0.25-0.79). The multiple-course group also had significantly less patent ductus arteriosus (20% vs 13%; P =.016). Incidence of death before discharge and other neonatal morbidities were similar. The multiple-course group had a reduction of 0.46 +/- 0.19 cm in head circumference at birth (P =.013) when adjusted for gestational age and preeclampsia. The 2 groups had similar birth weights. Infants born at > or =35 weeks' gestation, multiple-gestation infants, and infants who were born >7 days after the last corticosteroid dose had similar outcomes, regardless of the number of courses they received. Mothers treated with multiple courses compared with a single course had a significantly higher incidence of postpartum endometritis (P =.013), even though they had a lower incidence of prolonged rupture of membranes (24% vs 33%, P =.06) and similar cesarean delivery rates.

CONCLUSION

Exposure to multiple courses of antenatal corticosteroids compared with a single course resulted in a significant reduction in the incidence of respiratory distress syndrome in singleton preterm infants delivered within a week of the last corticosteroid dose. This was associated with a reduction in birth head circumference and an increased incidence of maternal endometritis. Whether the potential benefits of repeated therapy clearly outweigh the risks will ultimately be determined in randomized prospective controlled trials.

Pulmonary function and electrolyte balance following spironolactone treatment in preterm infants with chronic lung disease: a double-blind, placebo-controlled, randomized trial

OBJECTIVE

To study the effect of spironolactone on dietary electrolyte supplementation, pulmonary function, and electrolyte balance in premature infants with chronic lung disease.

STUDY DESIGN

A double-blind, randomized, and placebo-controlled trial was designed to study two groups of low birth weight infants with chronic lung disease at Pennsylvania Hospital. The placebo group received chlorothiazide and a placebo, and the spironolactone group received chlorothiazide and spironolactone during the 2-week study period. A two-tailed t-test was used to determine equivalence between the two groups.

RESULTS

Pulmonary compliance, resistance and tidal volume, serum sodium and potassium, and FIO2, were not statistically different between the two groups. The need for sodium and/or potassium chloride did not differ between the two groups, nor did the quantity of each salt.

CONCLUSION

The addition of spironolactone did not reduce the requirement for supplemental electrolytes, nor did it improve pulmonary mechanics or electrolyte balance.

Prophylaxis against early adrenal insufficiency to prevent chronic lung disease in premature infants

BACKGROUND. Many extremely low birth weight infants (<1000 g) show biochemical evidence of adrenal insufficiency in the first week of life, correlating with subsequent development of chronic lung disease (CLD).

METHODS

We conducted a randomized, double-masked, placebo-controlled pilot study to test whether early treatment with low-dose hydrocortisone for 12 days (1 mg/kg/day for 9 days followed by.5 mg/kg/day for 3 days), begun before 48 hours of life, would increase the likelihood of survival without CLD.

RESULTS

Forty patients were enrolled at two centers. Birth weight and gestation were similar for treatment and placebo groups: 732 +/- 135 g versus 770 +/- 135 g and 25.2 +/- 1.3 weeks versus 25.4 +/- 1.5 weeks. More infants treated with hydrocortisone achieved study success, defined as survival without supplemental oxygen at 36 weeks' postconception (12/20 [60%] vs 7/20 [35%]). Lower birth weight, histologic chorioamnionitis, and preeclampsia were significant risk factors, whereas study center, prenatal steroids, sex, and ethnicity were not significant. Hydrocortisone treatment decreased days on >40% oxygen, days on >25% oxygen, days on ventilator, and oxygen at discharge. Among infants exposed to chorioamnionitis, hydrocortisone treatment also was associated with increased enteral intake during the first month of life and with increased weight at 36 weeks' postconception. Five treated infants and 6 placebo infants developed sepsis; 3 in each group died.

CONCLUSIONS

First, early treatment with low-dose hydrocortisone in this population of extremely low birth weight infants increased the likelihood of survival without CLD. Second, the benefit was particularly apparent in infants with chorioamnionitis. Third, a larger multicenter trial is needed to verify the primary outcome and to better evaluate risks and benefits.

Regional hemodynamic effects of dopamine in the sick preterm neonate

OBJECTIVE

To study the effects of dopamine on renal, mesenteric, and cerebral blood flow in sick preterm neonates.

STUDY DESIGN

The pulsatility index was used to assess the dopamine-induced changes in renal, mesenteric, and cerebral blood flow by means of color Doppler ultrasonography in 23 nonhypotensive preterm neonates (birth weight: 981 +/- 314 g; postnatal age: <2 days). Dopamine was given at a dose of 6.1 +/- 3.0 microgram/kg per minute to combat oliguria, impaired peripheral perfusion, or both. Blood flow velocity measurements were made before and during dopamine administration, with each patient serving as his or her own control subject.

RESULTS

Dopamine significantly increased blood pressure and urine output. Dopamine decreased the pulsatility index in the renal artery (2.98 +/- 1.18 vs 1.68 +/- 0.45; P <.05) while the pulsatility index in the superior mesenteric and medial cerebral artery was not affected. Thus renal blood flow increased while mesenteric and cerebral blood flow remained unchanged during dopamine treatment. The increase in renal blood flow was independent of the blood pressure changes.

CONCLUSIONS

These findings suggest a functionally mature renal, but not mesenteric, vasodilatory dopaminergic response in the preterm neonate. The observations also indicate the lack of an effect of low- to medium-dose dopamine on cerebral hemodynamics in the nonhypotensive preterm neonate.

Early diagnosis and treatment of neonatal sepsis

Perinatally acquired bacterial neonatal sepsis is a low incidence, high risk disease with a relatively benign treatment. Accurate diagnosis is difficult because there is no definitive diagnostic test; even blood cultures have an unacceptably low sensitivity. Therefore, the clinician must accept that a number of neonates who do not have the disease will have treatment initiated for sepsis. In order to treat rapidly all infants with sepsis and to minimize therapy for those without infection, historical, clinical, and laboratory data can be used together in a management approach to achieve optimal results. A systemized approach using history, examination, sepsis screen laboratory tests, and cultures is presented to guide clinical management.

Effects of serotonin on cerebral circulation after middle cerebral artery occlusion

Serotonin (5-HT) produces constriction of peripheral collateral blood vessels. Using an animal model, the authors tested the hypothesis that 5-HT constricts collateral vessels in the cerebrum. A branch of the middle cerebral artery (MCA) was occluded proximally and cannulated distally in anesthetized dogs. Blood flow to the area at risk for infarction was detected by perfusing the cannulated MCA branch with microsphere-free blood during systemic injection of radioactive microspheres (shadow flow technique). Blood flow to collateral-dependent and normal cerebrum was measured during intravenous infusion of 5-HT (10 and 40 mg/kg/minute). Serotonin produced a dose-related reduction of blood flow to collateral-dependent cerebrum, increased collateral vessel resistance in large cerebral arteries and collateral vessels, and decreased cerebral artery perfusion pressure. In contrast, blood flow to normal cerebrum was not altered because a decrease in small vessel resistance effectively compensated for a decrease in MCA perfusion pressure. These findings indicate that 5-HT produces constriction of collateral vessels in the cerebrum. This response is clearly different from normal small cerebral vessels, which dilate during 5-HT infusion.

Macrosomic infants of nondiabetic mothers and elevated C-peptide levels in cord blood

C-peptide concentrations in the cord blood of 29 macrosomic neonates born of nondiabetic mothers were higher than in 23 control infants whose birth weight was appropriate for gestational age, and there was a significant direct correlation between birth weight and C-peptide concentration. Six of the macrosomic infants studied (20%) had hypoglycemia in the first 24 hours of life, compared with none of the infants born with appropriate weight. We conclude that chronic fetal hyperinsulinemia may be one of the causes of macrosomia and neonatal hypoglycemia in infants of nondiabetic mothers.

Secretory leukocyte protease inhibitor and lung inflammation in developing bronchopulmonary dysplasia

OBJECTIVE

To investigate secretory leukocyte protease inhibitor (SLPI) concentrations in tracheal lavage fluids of neonates with an endotracheal tube in place during the first month of life, and to evaluate the relationship of SLPI to neutrophil counts and elastase activity in patients in whom bronchopulmonary dysplasia (BPD) developed versus those in whom it did not.

DESIGN

A prospective, inception cohort study.

SETTING

University children's hospital neonatal intensive care unit.

PATIENTS

Fifty-three neonates who weighed < 2000 gm at birth, and who had an endotracheal tube in place, were enrolled. Forth-one patients survived to 28 days; BPD developed in 24 but not in 17 patients.

MAIN OUTCOME MEASURES

Tracheal lavage was performed on days 1, 2, 4, 7, 14, 21, and 28, and analyzed for neutrophils, elastase activity, and SLPI. Results were evaluated longitudinally for 28 days, and were compared between BPD and no-BPD groups during the first week.

RESULTS

SLPI concentrations increased significantly for all patients during the study period. During the first week, SLPI concentrations were similar between BPD and no-BPD groups; neutrophil counts and elastase activity were higher in the BPD group.

CONCLUSIONS

Patients in whom BPD ultimately developed had early evidence of increased pulmonary inflammation and a significantly less favorable protease-antiprotease balance. If elastase-induced injury contributes to the development of BPD, early therapy with recombinant SLPI might be beneficial by increasing the antielastase capacity of epithelial lining fluid.

Clinicopathologic approach to the diagnosis of neonatal sepsis

Perinatally acquired bacterial neonatal sepsis is a low incidence, high risk disease with a relatively benign treatment. Accurate diagnosis is difficult because there is no definitive diagnostic test; even blood cultures have an unacceptably low sensitivity. Therefore, the clinician must accept that a number of neonates who do not have the disease will have treatment initiated for sepsis. In order to treat rapidly all infants with sepsis and to minimize therapy for those without infection, historical, clinical, and laboratory data can be used together in a management approach to achieve optimal results.

Computed tomography versus magnetic resonance imaging in stereotactic localization

Neurosurgeons are often faced with a lesion that is obvious on magnetic resonance imaging (MRI), but not well-defined on computerized tomography (CT). However, questions remain regarding the distortion inherent in MRI images. Therefore the following comparative study was conducted. Five patients with intracranial lesions (1 lymphoma, 1 multiple sclerosis, 2 glioblastomas, and 1 AVM), underwent both CT and MRI for purpose of stereotactic biopsy or radiosurgery. The Brown-Roberts-Wells CT and MRI compatible localizing rings were used. Coordinates of the left optic nerve-globe junction, the aqueduct, pineal and optic chiasm were recorded from both CT and MRI. With MRI, all three imaging planes, axial, coronal and sagittal, were used. Coordinates were calculated in millimeters and submitted to statistical analysis using Pierson correlation coefficients. In all, there were 17 CT, 17 MRI axial, 13 MRI coronal, and 13 MRI sagittal coordinates. The analysis revealed that of the MRI coordinates, the axial coordinates were more available and retrievable. Lateral targets, such as the left optic nerve-globe junction, were more difficult to identify on coronal and sagittal images and often lacked a full compliment of fiducial points for calculation. The correlation with CT was best for axial, followed by coronal and then sagittal MRI planes. Geometric image distortion occurs owing to nonlinearity of the magnetic field as well as magnet susceptibility to different tissues at an interface. We feel that MRI stereotaxy can be utilized in conjunction with CT for verification of lesion coordinates in relatively large lesions, and particularly in those not well delineated on CT.

Long-term pulmonary consequences of respiratory distress syndrome in preterm infants treated with exogenous surfactant

The pulmonary outcome for preterm infants 1 year after synthetic surfactant replacement for respiratory distress syndrome was assessed by examining their pulmonary status and the results of pulmonary function tests. A total of 47 infants were followed: 13 infants mean +/- SD: birth weight, 1960 +/- 616 gm; gestation, 32 +/- 1.1 weeks) had been assigned to the placebo group and 34 (birth weight = 1890 +/- 530 gm; gestation = 32 +/- 2.5 weeks) to surfactant treatment. The infants were examined at 3 to 6 months of age (n = 45) and at 9 to 12 months of age (n = 36). There were no significant differences between the two groups in predisposing clinical conditions that would lead to chronic lung disease. The infants had similar patterns of growth, respiratory-related illness, and need for theophylline therapy, diuretic therapy, or both. None had hypoxemia by pulse oximetry. Mean (+/- SEM) values for pulmonary mechanics and energetics in surfactant-treated infants were significantly (p < 0.01) lower for total pulmonary resistance in late infancy (57.7 +/- 11.7 vs 35.3 +/- 4.6 cm H2O/L per second). Lower values (mean +/- SEM) of resistive work of breathing were also measured in the surfactant-treated group (60.7 +/- 12.0 vs 38.2 +/- 3.6 gm-cm/kg per breath). The dynamic pulmonary compliance values were in the low-normal range for both groups, and the mean (+/- SEM) peak-to-peak esophageal pressure values were elevated (11.47 +/- 2.26 cm H2O in the placebo group; 9.24 +/- 0.69 cm H2O in the surfactant group). Forced expiratory flow measurements in late infancy demonstrated significant (p < 0.01) improvement in expiratory reserves and reduced evidence of airflow obstruction in the surfactant-treated infants (peak flow (mean +/- SEM): 287.1 +/- 69 vs 396.9 +/- 27 ml/sec; forced expiratory flow (mean +/- SEM) at functional residual capacity: 56.3 +/- 7.5 vs 83.4 +/- 19.5 ml/sec). No significant differences in pulmonary functions were noted in early infancy. These data suggest that surfactant replacement for respiratory distress syndrome may be associated with beneficial long-term effects on the resistive airflow properties of larger preterm infants.

Pulmonary mechanics and energetics in preterm infants who had respiratory distress syndrome treated with synthetic surfactant

Pulmonary mechanics and energetics were determined in 32 neonates with respiratory distress syndrome, who were randomly assigned to receive treatment with an exogenous synthetic surfactant, Exosurf Neonatal, or air placebo. Pulmonary mechanics were measured before and 2 hours after surfactant (n = 13) or air placebo (n = 19) treatment, then longitudinally at 24, 48, and 72 hours after treatment, and again at 7, 14, and 28 days of age. There were no significant differences in the values for pulmonary mechanics or energetics 2 hours after the first dose of surfactant. Improvement in pulmonary mechanics was apparent 24 hours after surfactant treatment, when dynamic compliance was 36% greater than in the placebo group (p less than 0.03). Lung compliance values were also higher in surfactant-treated infants 48 and 72 hours after treatment, with a maximal increase of 64% at 7 days of age (p less than 0.03). Surfactant treatment also caused a significant decrease in total pulmonary resistance at 48 and 72 hours after initial treatment and at 14 days of age (p less than 0.04). Similarly, a decrease in flow-resistive work of breathing was demonstrated 24, 48, and 72 hours after surfactant treatment. At 28 days of age, pulmonary mechanics were not different in the two groups. We conclude that beneficial effects of surfactant on pulmonary mechanics were not apparent 2 hours after dosing but were evident 24 hours after dosing and persisted for the first 7 to 14 days of life.

Clinicopathologic approach to the diagnosis of neonatal sepsis

Perinatally acquired bacterial neonatal sepsis is a low-incidence, high-risk disease with a relatively benign treatment. Accurate diagnosis is difficult because there is no definitive diagnostic test; even blood cultures have an unacceptably low sensitivity. Therefore, the clinician must accept that a number of neonates will have treatment initiated for sepsis who do not have the disease. In order to treat rapidly all infants with sepsis and to minimize therapy for those without infection, historical, clinical, and laboratory data can be used together in a management approach to achieve optimal results.

Surfactant protein-A in bronchoalveolar lavage fluid from neonates with RDS on conventional and high-frequency oscillatory ventilation

Surfactant protein-A (SP-A) was measured in bronchoalveolar lavage (BAL) samples from ventilated neonates in order to study the concentration of SP-A with regard to: 1) high-frequency oscillatory ventilation (HFOV) vs. conventional mechanical ventilation (CMV); 2) the postnatal course and ontogeny of SP-A; and 3) the correlation with measurements of pulmonary function. Patients on HFOV had markedly lower BAL SP-A concentrations on days 1 and 2 compared to those on CMV, which may indicate influence of mode of ventilation on surfactant metabolism. The SP-A concentrations increased postnatally concurrent with resolution of acute respiratory distress syndrome. Finally, there were only weak correlations between BAL SP-A concentration and dynamic lung compliance and oxygen requirement.

Effects of dexamethasone and indomethacin on elastase, alpha 1-proteinase inhibitor, and fibronectin in bronchoalveolar lavage fluid from neonates

Elastase activity and concentrations of alpha 1-proteinase inhibitor, albumin, and fibronectin were measured in bronchoaleolar lavage (BAL) fluid from ventilated lungs in preterm neonates with lung disease before and after treatment with dexamethasone or indomethacin. Treatment with dexamethasone was associated with a significant decrease in BAL elastase activity but no change in fibronectin, albumin, or alpha 1-proteinase inhibitor concentrations. In contrast, treatment with indomethacin was associated with an increase in BAL elastase activity and fibronectin concentration, with no change in albumin or alpha 1-proteinase inhibitor concentrations. Control groups showed no changes in these BAL fluid biochemical markers during a similar time period. These data indicate that treatment with corticosteroids decreases lung inflammation as measured by BAL elastase activity. Corticosteroid treatment may not inhibit the development of pulmonary fibrosis, because fibronectin concentrations in BAL fluid were unaffected. Indomethacin treatment may augment lung inflammation and fibrosis by increasing BAL elastase activity and fibronectin concentration.

A chronic lung disorder following abdominal pregnancy

Abdominal pregnancy is a rare condition that is associated with a high infant mortality, as well as orthopedic and pulmonary deformations. This article describes the clinical and radiological courses of two infants born after abdominal pregnancies. Evidence of pulmonary hypoplasia secondary to fetal compression was present. The morbidity and mortality for infants born of abdominal pregnancies may depend on the extent of pulmonary involvement, which may relate to the length of fetal compression.

Diminished polymorphonuclear leukocyte adherence and chemotaxis following protein-calorie malnutrition in newborn rats

Recent advances in neonatal care have permitted the survival of very low birth weight infants who are difficult to nourish, and ultimately develop clinical and biochemical signs of malnutrition. These infants may be at greater risk for nosocomial infection than normally nourished hosts. We have compared neutrophil adherence and chemotactic responses in a newborn rat model of protein-calorie malnutrition. Wistar rats at 14 days gestation received either a normal (24% protein) or isocaloric (2.5% protein) diet. On day 5, rat pups were divided into three groups: pups allowed to nurse on their own dam (normal); normally nourished pups foster nursed onto a malnourished mother (depleted); or malnourished pups foster nursed to a normal dam (repleted). Granulocytes from depleted pups demonstrated significantly diminished adherence and chemotaxis when compared to normal or repleted pups. Thus, abnormalities of neutrophil function in malnourished newborn rats may contribute to increased susceptibility to bacterial infection.

Sepsis screen in neonates with evaluation of plasma fibronectin

Two hundred twenty neonates with suspected early onset sepsis were prospectively studied to evaluate the ability of a sepsis screen to discriminate infected from noninfected newborn infants. A positive sepsis screen consisted of positive findings in two or more of the following tests: total white blood cell count; immature/total neutrophil ratio; C-reactive protein; micro-erythrocyte sedimentation rate; or plasma fibronectin. For proved sepsis a four-part screen excluding fibronectin yielded a sensitivity of 100%, specificity of 83%, positive predictive value of 27% and negative predictive value of 100%. In contrast the sensitivity of white blood cell count and immature/total neutrophil ratio was only 46%. Adding fibronectin to the four-part screen provided equal sensitivity and negative predictive value but decreased specificity and positive predictive value. While plasma fibronectin may play an important role in the pathogenesis of neonatal sepsis, it is not useful as a marker for infection. The screens did not identify preterm infants with late onset nosocomial sepsis. Although clinical judgment should be the primary factor in the decision to institute antibiotic therapy, a simple four-part sepsis screen provides valuable presumptive information for excluding the diagnosis of early onset neonatal sepsis.

Improved survival and short-term outcome of inborn "micropremies"

Survival and significant chronic morbidity were determined by retrospective chart review for 107 inborn "micropremies." "Micropremies" are defined as appropriate-for-gestational age neonates of less than 1,001 grams and less than or equal to 28 weeks gestation. The overall survival rate for "micropremies" was 64 percent, ranging from 20 percent at 24 weeks to 83 percent at 27 weeks gestation. Race and sex are important determinants of survival in these infants. The incidence of severe, chronic morbidity in "micropremies" is relatively low. The acceptable outcome for "micropremies" supports aggressive perinatal management for fetuses as low as 24 to 25 weeks gestation. However, it is important for physicians to use current statistics from their own institutions when counseling parents and making management decisions.

Fibronectin and complement secretion by monocytes and peritoneal macrophages in vitro from patients undergoing continuous ambulatory peritoneal dialysis

We investigated the role of the opsonic glycoprotein fibronectin in the host defense of the peritoneum in patients undergoing continuous ambulatory peritoneal dialysis (CAPD). Fibronectin concentration in peritoneal dialysate from high infection rate CAPD patients (greater than 1.50 episodes peritonitis per year) was significantly less than from low infection rate CAPD patients (less than 0.55 episodes peritonitis per year). In vitro secretion of fibronectin by cultured peritoneal macrophages from patients with high infection rate was less than from low infection rate patients (P less than 0.05) and controls (P less than 0.01). In vitro secretion of the second component of complement, however, was similar in both high and low infection rate patients. Plasma fibronectin concentration and in vitro fibronectin secretion by cultured peripheral blood monocytes was not different between high infection rate patients and low infection rate patients, but was less than normals. Decreased fibronectin secretion by peritoneal macrophages is associated with a higher incidence of peritonitis among CAPD patients.

Tracheal lavage and plasma fibronectin: relationship to respiratory distress syndrome and development of bronchopulmonary dysplasia

Plasma for fibronectin determinations was obtained from 39 neonates with uncomplicated respiratory distress syndrome (RDS) and from 15 infants with RDS who developed bronchopulmonary dysplasia (BPD). Tracheal lavage fibronectin and albumin concentrations were measured in 15 infants with RDS and 15 with BPD. Control plasma fibronectin values were obtained from 20 healthy preterm infants on days 1, 2, 3, 14, and 30 of life. Control tracheal lavage fibronectin and albumin concentrations were measured in 17 neonates of various gestational ages who required tracheal intubation for nonpulmonary indications. Mean plasma fibronectin concentrations from patients with RDS was 121 +/- 11 micrograms/ml on days 1, 2, and 3, versus control level of 163 +/- 12 micrograms/ml (P less than 0.01). Mean tracheal lavage fibronectin/albumin ratio was 3.8 +/- 0.6 ng per microgram of albumin on days 1 to 5 for infants with RDS, versus control level of 5.6 +/- 3.6 (P = NS). Tracheal lavage fibronectin/albumin ratio from patients with BPD was elevated at 16.3 +/- 5.0 ng fibronectin per microgram of albumin on days 14 to 21, and 23.6 +/- 7.4 on day 30 (P less than 0.05 versus control and and versus RDS days 1 to 10). Low plasma fibronectin concentrations early in RDS may contribute to the development of pulmonary capillary leak. High tracheal lavage fibronectin levels may foster the development of pulmonary fibrosis in patients with BPD.

Effect of fibronectin on adherence of neutrophils from newborn infants

Neutrophils (polymorphonuclear leukocytes [PMNs]) from infants and adults increased in adherence over a 20-min incubation as measured in a morphological assay. At each time point, PMNs from healthy infants had significantly diminished adherence when compared with those of adults; PMNs from sick newborn infants showed intermediate adherence values. Moreover, PMNs from healthy infants had significantly diminished membrane fluorescence for fibronectin when compared with those of adults. Preincubation with exogenous fibronectin did not augment the adherence of PMNs from infants or adults. Deficient adherence of PMNs from newborns may be related to decreased membrane fibronectin.

Cystic fibrosis in Pueblo Indian children

Three Pueblo American Indian children with cystic fibrosis are described. The three cases constitute a higher incidence of cystic fibrosis in Pueblo Indians than would be expected from the known rarity of this disease in American Indian populations. This report discusses the possible genetic implications and emphasizes the need to consider the diagnosis of cystic fibrosis in American Indians with appropriate symptoms.

Decreased fibronectin biosynthesis by human cord blood mononuclear phagocytes in vitro

Cultured cord blood monocytes synthesize significantly less fibronectin than cultured monocyte-macrophages from adult peripheral blood. Biosynthesis of the second component of complement in vitro is similar for both cell systems. The monocyte-macrophages from neonates and adults have similar functional and morphologic properties in long-term cultures. The decreased monocyte-macrophage biosynthesis of fibronectin observed in vitro may be in part related to the reduced plasma fibronectin concentrations and reticuloendothelial system hypofunction which occur in newborn infants.

Decreased plasma fibronectin in neonatal sepsis

Fibronectin is a large opsonic glycoprotein which promotes reticuloendothelial system clearance of bacteria, immune complexes, collagenous debris, and damaged platelets. The concentration of plasma fibronectin is decreased in the newborn infant; however, the role of fibronectin in the onset and course of neonatal sepsis is unknown. Serial plasma fibronectin levels were determined in 19 neonates with documented bacterial sepsis. Plasma fibronectin concentrations decreased significantly (P less than .001) in all study infants concurrent with the development of septicemia. Recovery of plasma fibronectin to normal levels occurred by day 5 in premature neonates and by days 7 to 10 in term neonates. Fibronectin deficiency and resultant reticuloendothelial system impairment may decrease the ability of newborn infants to resist or clear bacterial infections. An acute reduction in the concentration of plasma fibronectin may be a valuable marker for neonatal sepsis.