Maternal diabetes induces changes in the umbilical cord gene expression

INTRODUCTION

Since maternal diabetes may affect fetal development and the umbilical cord provides an extension of the fetal vasculature, we decided to investigate cords' biological responses to maternal diabetic milieu.

METHODS

Using microarray analysis, we determined the gene expression profiles in the umbilical cords of six neonates born to type 1 diabetic mothers and in six control cords. Umbilical cord tissue was collected immediately after elective cesarean section. Expression data were confirmed by real-time polymerase chain reaction (11 genes). Additionally, the same umbilical cords were analyzed histologically.

RESULTS

Two hundred eighty six genes were differentially expressed in the umbilical cords from diabetic pregnancies compared to the controls (fold change ±1.5 and P < 0.01). Maternal diabetes had a major effect on the expression of genes involved in vascular development (Bone morphogenetic protein 4, Delta-like 1, and Notch homolog 4), vessel wall integrity (Collagen type VIII alpha 1, Myocyte enhancer factor 2C, and Matrix metalloproteinase 2), and vascular function (Natriuretic peptide precursor B, Endothelin 1, Endothelin receptor B, Cyclooxygenase 1, and Phosphodiesterase 5A). Maternal diabetes was associated with thicker umbilical vein intima-media layers and larger umbilical vein and artery intima-media areas compared to the controls.

DISCUSSION

Maternal diabetic environment seems to alter umbilical cord expression of genes involved in the regulation of vascular development and function with simultaneous umbilical vessel muscle layer thickening. These alterations suggest vascular phenotypic modifications, which in turn may lead to long-term vascular consequences in various tissues in infants of diabetic mothers.

Phospholipase A2 in meconium-induced lung injury

Although the triggering mechanisms of tissue inflammation and injury in meconium-contaminated lungs are still unclear, there is increasing evidence to suggest a central role for phospholipase A(2)'s (PLA(2)). In fact, elevated PLA(2) activities together with high enzyme concentrations, especially the amount of pancreatic (group I) secretory PLA(2) (PLA(2)-I), have been detected in human meconium and in meconium-contaminated lungs. Recent data from our laboratory further indicate that human pancreatic PLA(2), introduced in high amounts within aspirated particulate meconium, is a potent inducer of lung tissue inflammatory injury. Our finding of elevated human PLA(2)-I concentrations in plasma during the first hours after intratracheal meconium administration in newborn piglets further suggests that intrapulmonary aspiration of meconium could also have systemic inflammatory and injurious effects. This, however, remains to be studied in further detail.

Study orientations of graduate entry medical students

BACKGROUND

In order to meet the changing needs of health care, the University of Turku has introduced a graduate entry programme aimed at students with previous education and experience in health care professions.

AIMS

In this study, we look at the study performance of students with different educational backgrounds with special emphasis on graduate entry students.

METHODS

We surveyed the study orientations of 145 first-year medical students with different educational backgrounds in the Medical Faculty of the University of Turku, Finland. Special emphasis was placed on graduate entry students (n = 25) with previous education and work experience in health care professions. The students were characterized based on student records and the questionnaire Inventory of General Study Orientation (IGSO).

RESULTS

Our results revealed that after the first year of medical studies the graduate entry students showed exceptionally strong theoretical and practical commitment to their studies with a strong work-life orientation which makes them a distinct group among medical students.

Gene expression of pulmonary cytokines after sevoflurane or thiopentone anaesthesia in pigs

BACKGROUND

Volatile anaesthetics have diverse inflammatory effects on the lungs. They increase gene expression of some pro-inflammatory cytokines in alveolar macrophages whereas in alveolar type II cells they seem to decrease secretion and gene expression of pro-inflammatory cytokines. We have previously detected increased leukotriene C4, nitrate and nitrite concentrations in bronchoalveolar lavage fluid after sevoflurane anaesthesia. In the current study, we measured gene expression of inflammatory cytokines in the lung tissue and plasma concentrations of cytokines in pigs after thiopentone or sevoflurane anaesthesia.

METHODS

Sixteen pigs were randomly selected to receive either a continuous thiopentone infusion (control group, n = 8) or sevoflurane (n = 8) at 4.0% inspiratory concentration (1.5 MAC) in air for 6 h. Tissue samples were collected at the end of the study for measurement of gene expression of inflammatory cytokines. Blood samples were collected during anaesthesia for measurement of plasma cytokine concentrations.

RESULTS

Compared with thiopentone anaesthesia, lower gene expression of tumour necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) in lung tissue was observed after sevoflurane anaesthesia. Of measured cytokines IL-1beta, TNF-alpha, IL-6, IL-8 and IL-10 only plasma concentrations of IL-6 could be measured during the study without a difference between the groups.

CONCLUSION

Lower gene expression of TNF-alpha and IL-1beta was found in the intact porcine lung tissue after sevoflurane anaesthesia compared with thiopentone anaesthesia. Clinical significance of this finding is unknown.

Intravenous immunoglobulin g attenuates pulmonary hypertension but induces local neutrophil influx in meconium aspiration in piglets

BACKGROUND

Pulmonary hypertension and inflammation are well-identified pathogenetic features in meconium aspiration syndrome of newborns, but current approaches to their treatment or prevention are still often unsatisfactory.

OBJECTIVES

To investigate the possible protective effects of human intravenous immunoglobulin G (IVIG) on the hypertensive and inflammatory lung injury in severe neonatal meconium aspiration.

METHODS

Eleven newborn (10-12 days old) ventilated and catheterized piglets that received an intratracheal bolus (3 ml/kg) of a 65-mg/ml mixture of human meconium were studied for 6 h. IVIG was infused in 5 piglets 30 min before meconium administration, and 6 piglets served as controls and received the vehicle only.

RESULTS

Meconium instillation induced a biphasic pulmonary hypertensive response, which was significantly diminished by IVIG pretreatment. Similarly, IVIG improved the oxygenation of the piglets, but the intrapulmonary shunt fraction or systemic hemodynamic parameters did not differ between the study groups, except of a minor decrease in the mean arterial blood pressure caused by IVIG. The blood leukocyte count was comparable in the 2 groups. The lung tissue ultrastructural and histological changes, number of apoptotic cells and phospholipase A2 activity were similar in the 2 groups. The amount of neutrophil accumulation, assessed by myeloperoxidase activity, was however significantly increased in macroscopically damaged lung tissue after IVIG administration.

CONCLUSIONS

Our results thus indicate that IVIG treatment of newborns with severe meconium aspiration significantly diminishes the pulmonary hypertensive response and improves oxygenation, but the effects do not extend to protection of lung cellular injury.

Corticosteroid treatment in meconium aspiration syndrome: a solution for better outcome?

Corticosteroid treatment in severe meconium aspiration syndrome may afford, especially if started early, some improvement in oxygenation, lung function and pulmonary haemodynamics during the acute phase of the disorder. Still, the effects of corticosteroids on lung tissue perturbations and outcome of diseased infants remain unclear.

CONCLUSION

Further research is needed to determine the clinical significance and optimal timing and dosing of corticosteroid treatment in severe meconium aspiration syndrome.

Maturational changes in ovine pulmonary metabolism of platelet-activating factor: implications for postnatal adaptation

We recently reported that PAF acetylhydrolase (PAF-Ah) mRNA level and PAF-Ah activity in lamb lungs are up-regulated in the immediate newborn period, thereby facilitating the fall in postnatal PAF levels as well as a fall in pulmonary vascular resistance (B. O. Ibe, F. C. Sardar, and J. U. Raj, Mol Genet Metab 69:46-55, 2000). We have studied hypoxia effects on PAF synthesis and PAF-Ah activity in fetal lamb pulmonary arterial smooth muscle cells (FPASMC) and endothelial cells (FPAEC). We also studied PAF synthesis by platelets, and PAF-Ah activity in plasma of perinatal lambs at different ages. PAF synthesis (means +/- SEM, pmol/10(6) cells) by SMC in baseline was 168 +/- 27 and increased 3-fold on stimulation with A23187. Hypoxia augmented A23187-stimulated PAF synthesis by 30%. In FPAEC, baseline synthesis was 0.54 +/- 0.062 and increased 3-fold to 1.72 +/-.34. Hypoxia had no effect on PAF synthesis by EC. FPASMC produced over 300-fold more PAF than FPAEC. PAF synthesis by platelets was 47.02 +/- 7.1, 63.4 +/- 6.6, 71.5 +/- 9.9, and 62.2 +/- 5.2 for fetal, and newborn lambs <2 h, <1 day, and 6-12 days, old, respectively. PAF synthesis by platelets of <1 day-old lambs was different from that of fetal lambs. PAF-Ah activity (nmol lyso-PAF/min/mg protein) by FPASMC in normoxia was 3.41 +/- 0.38 which was 50% higher than the rate in hypoxia. Activity in FPAEC was 1.75 +/- 0.37 which was not different from hypoxia. PAF-Ah activity in fetal lamb plasma was 47.83 +/- 6.87 which was different from 155.32 +/- 12.10, the activity in plasma of newborn <1 day old. Activity in the other perinatal lambs did not differ from fetal or newborn <1 d. Our data suggest that lower pulmonary vascular PAF synthesis in normoxia together with higher PAF-Ah activity during immediate postnatal period is necessary to ensure rapid catabolism of PAF in vivo so as to facilitate postnatal adaptation of the pulmonary and systemic circulations.

Maternal magnesium sulfate treatment is associated with reduced brain-blood flow perfusion in preterm infants

OBJECTIVE

To examine the influence of antenatally administered magnesium sulfate (MgSO4) and ritodrine on cerebral blood flow and systemic hemodynamics in preterm infants.

DESIGN

Prospective, observational study.

SETTING

Neonatal intensive care unit of a university central hospital.

PATIENTS

Fifty-five preterm infants age <33 wks of gestation.

INTERVENTIONS

Serial Doppler examinations of the brain circulation, heart rate, systemic blood pressure, and echocardiographic assessment of ductus arteriosus shunting were performed during the first week of life in infants exposed antenatally to maternal MgSO4 (n = 19) or ritodrine treatment (n = 17), and in 19 nonexposed preterm controls.

MEASUREMENTS AND MAIN RESULTS

Cerebral blood flow velocity measurements were obtained from the anterior cerebral artery and internal carotid artery. Perfusion pressure and indices of resistance and blood flow in both vessels were subsequently derived. Maternal MgSO4 had no effect on neonatal cerebral blood flow velocity or resistance, but was associated with decreased (p <.05) perfusion pressure and blood flow in the anterior cerebral artery and internal carotid artery during the first day of life. Systolic blood pressure and pulse pressure were also lower (p <.05) during the whole study period in the MgSO4-exposed infants when compared with the controls. Maternal ritodrine treatment, on the other hand, had no consistent effects on either neonatal cerebral or systemic hemodynamics.

CONCLUSIONS

Our data indicate that maternal MgSO4 treatment, in contrast to antenatal ritodrine, is associated with lowered cerebral perfusion in preterm infants on the first day of life.

Meconium aspiration syndrome: a role for phospholipase A2 in the pathogenesis?

The pathophysiology of neonatal meconium aspiration syndrome (MAS), often resulting in severe respiratory failure, is complex and still largely unclear. Factors involved in the propagation of acute lung injury after perinatal aspiration of meconium include obstruction of the airways, ventilation/perfusion mismatch, increase of the pulmonary vascular resistance and a rapidly developing parenchymal and alveolar inflammatory reaction with associated surfactant dysfunction.

CONCLUSION

Although the early pulmonary inflammatory response is believed to play a central pathogenetic role in the meconium-induced acute lung damage, its initiating mechanisms are still poorly defined. However, increasing evidence indicates a direct toxic effect of meconium.

Antenatal magnesium sulphate exposure is associated with prolonged parathyroid hormone suppression in preterm neonates

The effects of maternal magnesium sulphate treatment on neonatal mineral status and parathyroid hormone secretory response were studied in 8 exposed and 27 control preterm infants during the first 2 wk of life. Antenatal magnesium sulphate resulted in hypermagnesaemia during the first 3-7 d of life without affecting other serum mineral concentrations.

CONCLUSION

Early hypermagnesaemia was associated with hypercalciuria during the first 3 d and parathyroid hormone suppression up to the age of 2 wk in the exposed infants.

Dexamethasone treatment attenuates pulmonary injury in piglet meconium aspiration

To investigate the pulmonary effects of steroid treatment in neonates with meconium aspiration, 25 10- to 12-d-old piglets were studied for 6 h after an intratracheal bolus of human meconium. Dexamethasone (0.5 mg/kg) was given in two treatment schedules, either 1 h before (n = 6) or 1 h after meconium instillation (n = 8). Eight piglets served as controls. Three additional piglets were given dexamethasone without meconium instillation. Pulmonary hemodynamics and oxygenation were followed, and lung tissue samples investigated for signs of inflammation and ultrastructural injury, including apoptosis. Pulmonary artery pressure and vascular resistance increased after meconium instillation, but this rise was significantly prevented after prophylactic dexamethasone. This treatment also improved the acutely deteriorated oxygenation of the piglets after meconium insufflation. Prophylactic, but not early, dexamethasone treatment further protected the lungs from the ultrastructural changes caused by meconium instillation. Additionally, the increase of apoptotic epithelial cell deaths was significantly prevented by both dexamethasone treatments. These results show that prophylactic dexamethasone treatment significantly attenuates the early pulmonary hemodynamic deterioration and structural lung damage caused by meconium aspiration. Further studies on the apoptosis-inhibiting effect of dexamethasone administration in neonatal lungs exposed to heavy meconium are warranted.

Human meconium has high phospholipase A2 activity and induces cellular injury and apoptosis in piglet lungs

Aspiration of meconium produces an inflammatory reaction resulting in necrotic changes in lung tissue. To further investigate the mechanisms of the meconium-induced early pulmonary injury, twenty 10-12-d-old piglets were studied for lung tissue ultrastructural and apoptotic changes and phospholipase A2 activity. Twelve piglets received an intratracheal bolus (3 mL/kg) of a 20-mg/mL (thin, n = 6) or 65-mg/mL (thick, n = 6) mixture of human meconium, and control piglets (n = 5) received the same amount of intratracheal saline. Three ventilated piglets with no aspiration were also studied. Pulmonary hemodynamics and systemic oxygenation were followed for 6 h after meconium or saline insufflation. In the control groups, the pulmonary tissue showed open alveolar spaces and intact vascular walls, whereas meconium administration resulted in severe pneumonitis, with alveolar spaces filled with inflammatory exudate. Meconium instillation additionally resulted in edematous changes in the vascular walls and alveolar epithelium, whereas type II pneumocytes were intact. The amount of apoptotic cells was increased, especially in the respiratory epithelium, and the catalytic activity of phospholipase A2 in lung tissue samples was significantly elevated after thick meconium instillation. This activity rise proved to be mainly because of human group I phospholipase A2, introduced by meconium. Our data thus show that aspiration of meconium leads to severe lung tissue inflammation with early ultrastructural changes in the pulmonary alveolar walls and is associated with apoptotic cell death in the epithelium, already during the first hours after the insult. These results further suggest that high phospholipase A2 activity, mainly introduced into the lungs within the meconium, may have an important role in the initiation of these alterations in neonatal lungs.

Nitric oxide inhalation inhibits pulmonary apoptosis but not inflammatory injury in porcine meconium aspiration

To investigate the possible protective effects of nitric oxide (NO) inhalation in newborns with meconium aspiration, 18 10-12-d-old piglets were studied for 6h after an intratracheal bolus (3 ml/kg) of a 65-mg/ml mixture of human meconium. Twelve of the piglets were treated with continuous NO inhalation at a dose of 1 ppm (n = 6) or 10 ppm (n = 6), started 30 min before the insult. Pulmonary haemodynamics and systemic oxygenation were followed, and lung tissue samples were studied for signs of inflammation, evidence of ultrastructural injury and apoptotic cell changes. Inhalation of 10 ppm NO, in contrast to 1 ppm NO, significantly delayed the meconium-induced pulmonary pressure rise and the increase in intrapulmonary shunt fraction, and maintained better oxygenation in the piglets. Histologically and biochemically, treatment with 1 or 10 ppm NO inhalation did not protect the lungs against meconium-induced inflammatory injury. Further, ultrastructural lung tissue analysis revealed a significant amount of alveolar exudate and oedematous alveolar epithelium and endothelium after meconium instillation, also in the lungs treated with NO inhalation. However, the increase in apoptotic epithelial cell deaths, previously shown to be stimulated by intratracheal meconium, was significantly impeded after inhalation of 10 ppm. These results thus show that early continuous NO inhalation controls the rise in pulmonary artery pressure and improves the efficiency of arterial oxygenation, and further prevents the increase in epithelial apoptosis, but does not protect against early inflammatory damage caused by meconium aspiration.

Association of low-density lipoprotein oxidation to abnormal electrocardiographic late potentials

In vivo oxidation of low-density lipoprotein is shown to be significantly related to another risk factor for coronary atherosclerosis, abnormal electrocardiographic late potentials, in clinically healthy pilots. Because both of these variables have been also associated with cardiac arrhythmogenic action, together they may improve the identification of patients at risk of ventricular tachyarrhythmias.

Meconium stimulates cyclooxygenase-2 expression in rat lungs

Since meconium aspiration often induces an inflammatory respiratory disorder, we investigated the effects of intrapulmonary meconium on the expression of cyclooxygenase-1 and 2 in rat lungs. Suspension of human meconium was instilled intratracheally into ventilated lungs of anesthetized rats, while control rats received an equal volume of saline. The meconium lungs were ventilated either with air or 100% oxygen, and control lungs were ventilated with air. After 3 h, the lungs were removed and the amount of cyclooxygenase-1 and 2 mRNA was measured by Northern blot analysis. Cyclooxygenase-1 mRNA was clearly expressed in control rat lungs, while cyclooxygenase-2 expression was minimal. Meconium administration markedly upregulated the expression of cyclooxygenase-2 mRNA, while cyclooxygenase-1 expression remained unchanged. Increased expression of cyclooxygenase-2 was detected in rat lungs ventilated with either air or oxygen. Our data thus indicate that meconium aspiration induces pulmonary expression of cyclooxygenase-2, suggesting an important role for prostaglandins in the meconium aspiration-induced inflammation in neonatal lungs.

Involvement of thromboxane A2 and prostacyclin in the early pulmonary hypertension after porcine meconium aspiration

Severe perinatal aspiration of meconium is frequently complicated by unsuccessful neonatal adaptation with associated pulmonary hypertension. This vascular complication is supposedly related to pulmonary release of vasoconstrictory agents, including metabolites of arachidonic acid. Thus, to investigate the role of prostanoids on these meconium-induced circulatory changes in the lungs, the hemodynamic response to meconium instillation was studied in acetylsalicylic acid-pretreated juvenile pigs. Twelve 10-wk-old pigs with adapted lung circulation received 3 mL/kg of 65 mg/mL human meconium via the endotracheal tube. Six of them were medicated with 10 mg/kg acetylsalicylic acid 30 min before meconium insufflation. Hemodynamic parameters and urinary excretion of stable metabolites of thromboxane A2 and prostacyclin were measured serially for 6 h after the insult. Meconium administration induced a biphasic increase in mean pulmonary artery pressure and pulmonary vascular resistance, and a rapid rise in urinary levels of prostanoid metabolites. Acetylsalicylic acid pretreatment prevented the initial (0-1 h) pulmonary hypertensive response and increase in prostanoid excretion. During the second phase (1-6 h), acetylsalicylic acid did not attenuate the progressive increase in mean pulmonary artery pressure and pulmonary vascular resistance nor did it affect the longitudinal distribution of the pulmonary resistances. Our results thus show that in adapted porcine lungs, arachidonic acid metabolites contribute to the early hypertensive response, but have only minor effects during the second phase vascular hypertension.

Endothelin-1, atrial natriuretic peptide and pathophysiology of pulmonary hypertension in porcine meconium aspiration

To evaluate the role of endothelin-1 (ET-1) and atrial natriuretic peptide (ANP) in the development of meconium aspiration-induced pulmonary hypertension, plasma ET-1 and ANP levels were measured serially for 6h after meconium instillation in juvenile pigs. Eleven 10-week-old, anaesthetized and catheterized pigs received intratracheally a bolus of 3 ml kg(-1) 20% human meconium, and five of them were premedicated with 30 mg kg(-1) methylprednisolone i.v. Another six pigs served as controls and were given 3 ml kg(-1) sterile saline intratracheally. Meconium instillation resulted in an increase in plasma ET-1 levels with a significant correlation to the simultaneously increasing PVR (r = 0.72). Methylprednisolone had no effect on the early (0-1 h) ET-1 increase, but prevented significantly the second phase (1-6 h) rise with a concomitant attenuation of the progressive pulmonary hypertension. ANP concentrations were higher in the meconium than in the control group throughout the study and further increased after steroid treatment with a good correlation to ET-1 (r = 0.86). Thus, the postinjury rise in circulating vasoactive peptides, together with the pulmonary hypertensive response, and modulation of the peptide balance and pressor reaction by steroids, suggest a contributory role for ET-1 and ANP in the development of pulmonary hypertension after meconium aspiration.

Meconium aspiration induces a concentration-dependent pulmonary hypertensive response in newborn piglets

To investigate the effects of aspirating different meconium concentrations on the pulmonary circulation in 10- to 12-day-old piglets, 30 catheterized animals were studied. The piglets received an intratracheal bolus of 3 ml/kg of a mixture of human meconium in saline with concentrations of 20 mg/ml (light, n = 7), 40 mg/ml (moderate, n = 6), or 65 mg/ml (thick, n = 10) meconium in saline. Control piglets (n = 7) received 3 ml/kg of intratracheal saline. Pulmonary and systemic pressures were measured and vascular resistances calculated at baseline and serially for 4 hours after instillation. Four of the piglets died early and were excluded from the study. In addition, 23 samples of human meconium-stained amniotic fluid were collected at delivery for determination of their meconium concentration. After an initial rise in pulmonary artery pressure and vascular resistance after meconium and saline instillation, pulmonary artery pressure and resistance increased progressively and concentration-dependently in the meconium groups, but returned to baseline in the control group. The saline and meconium-induced initial increases, and the subsequent meconium-stimulated progressive rise in vascular resistance occurred mainly in the postarterial segment. There were no significant changes in systemic hemodynamics. Mean airway pressure increased and oxygenation deteriorated after meconium instillation. The impairment of oxygenation depended on the meconium concentration in the instilled bolus and persisted throughout the study after moderate and thick meconium instillation. Similarly, the intrapulmonary shunt fraction increased initially and remained elevated in the moderate and thick meconium groups. Meconium concentrations in the human amniotic fluid samples were in the same range as concentrations used in the present experimental study. These results indicate that aspirated meconium at concentrations found in light to moderate meconium-stained human amniotic fluid has significant effects on pulmonary hemodynamic and oxygenation in newborn piglets.

Transcephalic electrical impedance in the study of cerebral circulation in a juvenile pig model

Transcephalic electrical impedance offers a technique for non-invasive, cot-side monitoring of neonatal cerebral circulation but the exact nature of the signal is somewhat ambiguous. The impedance signal is examined in an animal project where the ventilator settings are adjusted (20 min-1-10 min-1-40 min-1 for 10 min periods each) to produce circulatory changes. Six juvenile pigs are intubated, and ECG, arterial blood pressure, carotid flow (CF) by electromagnetic flowmeter and impedance are continuously monitored and stored on analogue tape. Cardiac output by thermodilution, blood oxygen (pO2) and carbon dioxide (pCO2) tensions are measured. ECG is converted to heart rate, mean blood pressure is integrated, and the high-frequency (1.50-4.00 Hz) component of the impedance signal delta Z is computed using autoregressive spectral estimation. Stroke volume, peripheral vascular resistance (PVR) and cerebral vascular resistance (CVR) are calculated. pCO2 and CF increase and pO2 decreases during hypoventilation. CF correlates positively with cardiac output, stroke volume, delta Z and pCO2, and negatively with pO2 and CVR. delta Z correlates positively with heart rate and cardiac output, and negatively with PVR and CVR. It is concluded that the impedance signal is related to the amount of blood transmitted to the brain by every beat of the heart, depending on the changes in both the systemic circulation and the cerebral vascular compliance.

Methylprednisolone attenuates the pulmonary hypertensive response in porcine meconium aspiration

Severe neonatal aspiration of meconium is frequently complicated by fatal pulmonary hypertension. The protective effect of an i.v. bolus of methylprednisolone on meconium aspiration-induced hypertensive lung injury was studied in anesthetized pigs with adapted lung circulation. Eleven 10-wk-old pigs received 3 mL/kg 20% human meconium via the endotracheal tube. Five of them were pretreated with 30 mg/kg methylprednisolone 30 min before aspiration. Ventilator settings were adjusted to keep arterial PO2 above 8 kPa and arterial PCO2 below 5 kPa. Meconium insufflation induced a biphasic pulmonary pressor response during the 6 h follow-up. Methylprednisolone tended to prevent the early (0-1 h) increase in pulmonary artery pressure and inhibited significantly the second phase (1-6 h) progressive rise in pulmonary artery pressure and pulmonary vascular resistance. This inhibition of resistance increase was most profound in the postarterial segment of the lung circulation, as determined by pulmonary artery occlusion. Additionally, the methylprednisolone pretreated group demonstrated a significant decrease in venous admixture together with improved oxygenation during the late phase after the insult, and further showed evidence of diminished lung edema formation. Although meconium aspiration-induced fall in blood leukocyte concentration was inhibited by methylprednisolone pretreatment, no histologic difference was found in pulmonary leukocyte sequestration. Our results thus show that in adapted porcine lungs methylprednisolone pretreatment improves oxygenation and attenuates the meconium aspiration-induced pulmonary hypertensive response by preventing the increase in the postarterial resistance.

Adenosine triphosphate treatment for meconium aspiration-induced pulmonary hypertension in pigs

To investigate the pulmonary haemodynamic effects of meconium aspiration and subsequent adenosine triphosphate (ATP) treatment, 12 anaesthetized and ventilated pigs (wt 24-28 kg) received either ATP or an equal volume of saline into the right heart in doses of 0.02 to 0.80 mumol kg-1 min-1 after intratracheal administration of 2 mL kg-1 of human meconium. Meconium instillation induced significant increases in pulmonary vascular pressures and total and postarterial resistances calculated from pulmonary artery occlusion studies, but did not affect the systemic haemodynamics, except for a fall in heart rate and increase in central venous pressure. Infusion of ATP at the lowest doses (0.02 and 0.08 mumol kg-1 min-1) selectively decreased the pulmonary arterial pressure and vascular resistance and at 0.32 and 0.80 mumol kg-1 min-1 reduced both the pulmonary and systemic resistances. In the lung circulation the increasing doses of ATP reduced preferably the arterial but also the postarterial resistance. Withdrawal of ATP infusion led to a significant rebound effect especially in the postarterial segment of the lung circulation. Meconium aspiration thus induces an acute, predominantly postarterial obstruction in the lung circulation and infusion of ATP at low doses selectively dilates the pulmonary vascular bed and may help to preclude elevation of capillary pressures in meconium aspiration-induced pulmonary hypertension.

Meconium aspiration induces ARDS-like pulmonary response in lungs of ten-week-old pigs

To investigate whether aspiration of meconium induces a hemodynamic and histologic pulmonary response similar to that frequently seen in experimental acute respiratory distress syndrome, twelve 10-week-old pigs with postnatally adapted lungs were studied. Six 10-week-old pigs received 3 ml/kg 20% human meconium via the endotracheal tube. Six control pigs of the same age were given sterile saline. Ventilator settings were adjusted to keep PaO2 above 8 kPa and PaCO2 below 5 kPa. The pulmonary hemodynamic response to aspiration consisted of two separate hypertensive components. An initial peak in pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) was followed by a progressive increase in PAP and PVR in the meconium group, whereas in the saline group these parameters returned to baseline levels. The distribution of PVR, determined by pulmonary artery occlusion, was characterized by an increase in the postarterial resistance immediately after meconium aspiration and a progressive increase in both arterial and postarterial resistance during the later phase. On histological examination, marked neutrophil sequestration was seen in the meconium lungs. In addition, lung edema formation was significantly enhanced in the meconium group, as shown by an increased lung wet/dry weight ratio. Thus, meconium aspiration resulted in a biphasic pulmonary pressor response and severe pulmonary inflammation. This response resembled that of models of experimental acute respiratory distress syndrome following diverse types of precipitating insults; this suggests that similar pathophysiologic mechanisms are elicited and cause similar pulmonary dysfunction following different forms of lung injury.

Human meconium has potent antioxidative properties

In vitro the antioxidative capacity of pooled and lyophilized human meconium, measured by chemiluminescence, was compared to that of three potent antioxidants: vitamin C, a vitamin E analogue and a synthetic antioxidant, butylated hydroxytoluene. Meconium showed a significant superoxide trapping and peroxidation prevention capacity, but its capacity to trap peroxyl radicals was minor. These effects of meconium were possibly due to bilirubin and ubiquinol-10, both found in high concentrations in meconium. It is speculated that human meconium may have a physiological role as an important endogenous antioxidant during perinatal transition.

Hemodynamic control of atrial natriuretic peptide plasma levels in neonatal respiratory distress syndrome

To evaluate the contribution of the pulmonary and ductal hemodynamics on the cardiac atrial natriuretic peptide (ANP) synthesis and release in neonatal respiratory distress syndrome, serial blood samples for plasma C-terminal end, and the more stable N-terminal end (NT-proANP) of the propeptide were obtained. Simultaneous evaluation of the systolic pulmonary artery pressure (PAP) and magnitude of ductal shunting by the Doppler method were made of 37 distressed infants during the first 4 days of life. Both plasma ANP and NT-proANP rose after birth, peaked at 48 hours of age, and correlated significantly (r = 0.66; p < 0.001; n = 78) with each other. The initially high systolic PAP and, since the systemic arterial pressure (SAP) did not change, the PAP/SAP ratio declined slowly during the study period, as did the magnitude of ductal left-to-right shunting after an initial increase during the first hours after birth. Plasma NT-proANP had a positive correlation to the magnitude of ductal left-to-right shunting both during the first 2 and 4 days of life, but did not correlate with PAP, SAP, or PAP/SAP ratio during the same time periods. Eight infants with delayed closure of the ductus maintained elevated plasma NT-proANP values after the second day of life.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute effects of synthetic surfactant replacement on pulmonary blood flow in neonatal respiratory distress syndrome

To assess the acute effects of surfactant replacement therapy on the pulmonary blood flow in neonatal respiratory distress syndrome (RDS), 23 distressed infants were studied before and for 1 hour after either synthetic surfactant instillation (n = 13) or endotracheal suctioning (n = 10). Doppler ultrasound was used to measure blood flow velocity and flow velocity integral, representing volumetric flow, of the left pulmonary artery branch, ductal left-to-right shunt, and ascending aorta. Surfactant instillation increased the left pulmonary artery and ductal shunt flow velocity and flow velocity integral for 1 hour in 10 of 13 treated infants, whereas no change was found after endotracheal suctioning. There was a significant (P < 0.05) correlation between the changes in the pulmonary artery and ductal flow values at 1 hour after surfactant treatment. The mean increase during 1 hour after treatment in the pulmonary artery flow ranged from 15 to 25% and in the ductal left-to-right shunt from 28 to 33%. No change in the aortic flow or heart rate was found in either group. Our results thus suggest that synthetic surfactant therapy may acutely increase pulmonary blood flow and ductal left-to-right shunting in infants with RDS.

Hormonal enteroinsular axis in newborn infants of insulin-treated diabetic mothers

To study whether the increased glucose levels in the amniotic fluid during diabetic pregnancies induce an early maturation of the hormonal enteroinsular axis, we measured blood glucose levels and plasma concentrations of C-peptide, pancreatic glucagon, enteroglucagon, and gastric inhibitory polypeptide (GIP) in cord blood from 18 newborn infants of insulin-treated diabetic mothers (IDM) and 18 infants of nondiabetic mothers. In addition, we studied the same parameters in 20 IDM and 12 control infants before and after their first feed comprising human milk (5 mL/kg), given by nasogastric tube at the age of 2 h. The IDM had significantly higher blood glucose levels and plasma C-peptide concentrations in their cord blood than the control infants, which was followed postnatally by a substantial fall in these levels, whereas a more modest decrease could be seen in the control infants. Circulating enteroglucagon and GIP concentrations at the age of 2 h were significantly higher than those observed in cord blood in both the IDM and the control infants, but the IDM had significantly lower blood glucose levels, higher plasma C-peptide, and lower enteroglucagon concentrations before the first feed. There was a significant increase in blood glucose levels after the feed in both the IDM and the control infants, and the concentrations 2 h after feeding were of the same magnitude in the two groups. No significant C-peptide response could be observed in either group, but the IDM continuously had higher C-peptide concentrations. A significant enteroglucagon and GIP response could be seen in the IDM, whereas the controls exhibited only a GIP response. However, no significant differences were found between the two groups in the absolute postprandial plasma concentrations of these hormones. Our results show rapid, substantial postnatal changes in circulating concentrations of enteroinsular hormones in both IDM and control infants. Enteral feeding with human milk corrects early postnatal hypoglycemia within 2 h in most IDM without causing any exacerbation of their hyperinsulinemia. The absence of any C-peptide response to the first feed and of any observed differences between IDM and normal infants in absolute concentrations of enteroglucagon and GIP after the first feed suggests that the enteroinsular axis matures postnatally in both groups of infants.

Maternal and neonatal C-reactive protein after interventions during delivery

To evaluate the effects of interventions during delivery on the maternal and neonatal C-reactive protein (CRP) we prospectively measured CRP by immunoturbidometry in 238 mother-infant pairs (179 normal vaginal deliveries, 36 cesarean sections and 23 vacuum extractions) at 24 and 72 hours after delivery. We additionally measured CRP in peripheral maternal and neonatal blood immediately after birth in 29 uncomplicated vaginal deliveries. CRP values in the mothers and their offspring were low at birth, but rose significantly during the first day after vaginal delivery. Cesarean section induced a pronounced elevation of maternal CRP, but had no effect on neonatal values. Delivery by vacuum extraction produced a transient elevation of both maternal and neonatal CRP at 24 hours after birth. Neonatal CRP values were not associated with presence or size of superficial birth tissue trauma evaluated simultaneously with blood sampling. Increased CRP release in mothers and their infants after interventions during delivery may be associated with varying degrees of tissue trauma and can complicate assessment of the presence of infection.

Pulmonary hemodynamics after synthetic surfactant replacement in neonatal respiratory distress syndrome

To evaluate the acute effects of surfactant replacement therapy on pulmonary circulation in neonatal respiratory distress syndrome, we studied 25 infants before and for 1 hour after either synthetic surfactant administration (n = 15) or endotracheal suctioning (n = 10). The noninvasive Doppler method was used to estimate systolic pulmonary artery pressure from tricuspid regurgitant flow velocity and to measure blood flow velocity of the left-to-right shunt through the ductus arteriosus. Pulmonary artery pressure decreased significantly within 15 minutes after surfactant administration and remained low throughout the study period, whereas suctioning did not change pulmonary artery pressure levels. No changes in systemic pressure were found in either group. Velocity of the ductal left-to-right shunting increased and remained elevated for 1 hour only in surfactant-treated infants. In addition, right-to-left ductal shunting disappeared in four infants after surfactant administration. Our data thus indicate that administration of synthetic surfactant to infants with respiratory distress syndrome reduces pulmonary vascular resistance, resulting in a decrease in pulmonary artery pressure and an increase in ductal flow velocity.

Synthetic surfactant replacement therapy decreases estimated pulmonary artery pressure in respiratory distress syndrome

OBJECTIVE

To evaluate the effects of surfactant replacement therapy on the pulmonary artery pressure in infants with respiratory distress syndrome.

DESIGN

Nonrandomized, "before-after" trial.

SETTING

Neonatal intensive care unit at a referral center.

PARTICIPANTS

Ten preterm infants with respiratory distress syndrome.

INTERVENTIONS

Administration of two or four doses of an exogenous synthetic surfactant at 12-hour intervals.

MEASUREMENTS AND RESULTS

Systolic pulmonary artery pressure was estimated by measuring tricuspid regurgitant flow velocity with the Doppler method before and, on average, 45 minutes after administration of synthetic surfactant. Measurable recordings were technically obtainable on 18 of 23 occasions. Surfactant instillation decreased pulmonary artery pressure significantly on 17 of 18 occasions, but did not change the systemic blood pressure. Twelve hours after surfactant treatment, pulmonary artery pressure measured on nine occasions returned to the pretreatment level. No change in the velocity or magnitude of the ductal left-to-right shunting due to exogenous surfactant was found.

CONCLUSIONS

Synthetic surfactant replacement therapy in infants with respiratory distress syndrome induces a significant, but transient decrease in systolic pulmonary artery pressure with no effect on the ductal shunt.

Maternal smoking and neonatal prostacyclin excretion

To study the effect of smoking during pregnancy on the production of vasodilatory, antiaggregatory prostacyclin (PGI2) of the neonates, we measured the urinary excretion of 6-keto-prostaglandin F1a (6-keto-PGF1a, a metabolite of PGI2) on the first and on the third or fourth day of life of a group of babies of smoking (BSM, n = 14) and nonsmoking (BNSM, n = 13) mothers. The urinary excretion of 6-keto-PGF1a was similar in both groups (249.8 +/- 18.5, mean +/- SEM, and 262.7 +/- 35.0 pg 6-keto-PGF1a/mmol of creatinine for BSM and BNSM, respectively, on the first day of life; 109.4 +/- 18.6 and 133.3 +/- 18.5 pg/mmol for BSM and BNSM, respectively, on the third or fourth day of life). Thus smoking during pregnancy is not followed by such changes of PGI2 production that they were reflected by changes of urinary 6-keto-PGF1a of newborns on the first or on the third or fourth day of life.

Platelet thromboxane B2 production in neonatal pulmonary hypertension

Production of platelet thromboxane B2, a stable metabolite of thromboxane A2, was measured in seven newborn infants with pulmonary hypertension during the first day of life. Platelet thromboxane B2 production was significantly lower than in 12 healthy controls but did not correlate with simultaneous blood gas values.

Maternal residual beta-cell function and the outcome of diabetic pregnancy

Preservation of own insulin production (residual pancreatic beta-cell function) has been shown to have a beneficial effect on glycemic control in insulin-dependent diabetic subjects, and its total lack has been suggested to be an independent risk factor during diabetic pregnancy. We studied the influence of residual beta-cell activity on the glucose control and the outcome of pregnancy in 29 diabetic women by sequentially measuring gestational postprandial plasma C-peptide (CPR) levels, diurnal blood glucose curves and blood glycosylated hemoglobin (Hb A1c) and by analyzing the morbidity and mortality of the offsprings. The 9 diabetics with moderate own insulin secretion (CPR levels over 1.0 microgram/l, White classes B and C, later referred to as group I) had significantly better glucose control than the remaining 20 subjects with lower CPR values (White classes C, D and NF, later referred to as group II) (figure 1, table I). There were two intrauterine deaths, both in group II. These deaths (one caused by multiple congenital contracture syndrome and the other by severe intrauterine growth retardation without any evident cause) could not be straightly connected with diabetes. Respiratory distress syndrome was seen in group II only. There was no other significant difference in the neonatal morbidity between the two groups (table II). All mothers of RDS infants were in White class NF where the birthweight was also smaller than in classes B and C. These were the only differences in neonatal morbidity between the White classes (table III). In conclusion, moderate residual beta-cell function seemed to be clinically important in maintaining strict glucose control during gestation.(ABSTRACT TRUNCATED AT 250 WORDS)

Maternal ingestion of acetylsalicylic acid inhibits fetal and neonatal prostacyclin and thromboxane in humans

Small doses of maternal acetylsalicylic acid have proved to prevent preeclampsia. To study the mechanism of this action of acetylsalicylic acid, healthy women ingested 100 mg (n = 13) or 500 mg (n = 14) of acetylsalicylic acid during labor at term. The fetal prostacyclin synthesis, as assessed by the production of 6-ketoprostaglandin F1 alpha (a metabolite of prostacyclin) by the umbilical artery, was reduced from 21.3 +/- 1.6 ng/gm/min of dry weight in the controls (n = 25, mean +/- SE) to 7.8 +/- 1.1 ng/ml/min (p less than 0.001) in infants of mothers receiving 500 mg of acetylsalicylic acid, but it was unchanged in infants with mothers receiving 100 mg of acetylsalicylic acid (19.5 +/- 2.3 ng/gm/min). Maternal ingestion of 500 mg of acetylsalicylic acid also was accompanied by reduced (p less than 0.10) urinary excretion of 6-ketoprostaglandin F1 alpha in neonates during the first 3 days of life. The fetal platelet thromboxane A2 synthesis, as assessed by the release of thromboxane B2 (a metabolite of thromboxane A2) during spontaneous clotting of the umbilical blood (63.4 +/- 4.2 pg/10(5) platelets, n = 22), was inhibited in infants born to mothers given 100 mg (14.0 +/- 3.7 pg/10(5) platelets, p less than 0.001) or 500 mg of acetylsalicylic acid (6.1 +/- 3.5 pg/10(5) platelets, p less than 0.001). The thromboxane B2 release by the umbilical artery (1.1 +/- 0.1 ng/gm/min, n = 13) also was decreased in infants of mothers receiving 500 mg of acetylsalicylic acid (0.57 +/- 0.1 ng/gm/min, n = 7, p less than 0.01). Thus a small dose of maternal acetylsalicylic acid (100 mg) inhibits only the fetoplacental thromboxane A2 but leaves prostacyclin production unaffected.

Dietary fatty acids and platelet thromboxane production in puerperal women and their offspring

The effects of the ratio of polyunsaturated to saturated fatty acids in the diet of puerperal women on maternal and neonatal fatty acids and thromboxane A2 synthesis were studied in 91 mother-infant pairs on the fourth to fifth day after delivery. The mothers received a diet with either a low (0.1) or a high (1.5) polyunsaturated to saturated fatty acid ratio for 4 to 5 days. The fatty acid composition in maternal and neonatal serum and in breast milk was determined in 34 mother-infant pairs from both dietary groups. The capacity of the platelets to produce thromboxane B2, a stable metabolite of thromboxane A2, was determined in another 57 mother-infant pairs. The percentage of linoleic acid was increased in maternal and neonatal sera as well as in the breast milk in the group with a high dietary polyunsaturated to saturated fatty acid ratio, whereas the content of arachidonic acid was increased only in maternal serum. This was accompanied by increased platelet thromboxane B2 production in the mothers, and maternal and neonatal thromboxane B2 synthesis correlated significantly with each other (r = 0.43, p less than 0.05). This finding may provide therapeutic possibilities in the future.

Increased platelet thromboxane B2 production in newborn infants of diabetic mothers

Platelet thromboxane B2 (TxB2) production, plasma concentrations of C-peptide and pancreatic glucagon as well as blood glucose levels were measured in 12 infants of insulin-dependent diabetic mothers and eight healthy controls at the age of two hours. Platelet TxB2 production (p less than 0.05) and plasma C-peptide levels (p less than 0.02) were significantly higher and blood glucose concentrations lower (p less than 0.002) in the infants of the diabetic mothers than in the controls. The data suggest that platelets of infants of diabetic mothers produce increased amounts of proaggregatory thromboxane A2, which may contribute to the hyperaggregation in these infants.

[Early closure of ductus arteriosus with indomethacin]

The open ductus arteriosus was closed with indomethacin on the first days of life in 13 out of 27 preterm infants with respiratory distress syndrome. The early medical closure of the ductus arteriosus shortened the duration of the ventilatory assistance and need of additional oxygen in these infants.

Plasma six-keto-prostaglandin F1 alpha and endocrine pancreatic function in the newborn infant of the diabetic mother

Plasma concentrations of 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), C-peptide and pancreatic glucagon and blood glucose levels were measured in 13 infants of insulin-dependent diabetic mothers at the age of 2 h. Plasma 6-keto-PGF1 alpha levels were lower in these infants when compared to those of healthy controls at the same age (p less than 0.05). Plasma 6-keto-PGF1 alpha correlated negatively with the C-peptide levels (r = -0.57; p less than 0.05) and positively with the pancreatic glucagon concentrations (r = 0.83; p less than 0.001) in the infants of diabetic mothers. No correlation with blood glucose concentrations was found. The data suggest that hyperinsulinemia in infants of diabetic mothers is associated with a decreased vascular prostacyclin production.

Immunoreactive thromboxane B2 and 6-keto-prostaglandin F1 alpha in neonatal hyperbilirubinemia

To study the effects of hyperbilirubinemia on platelet thromboxane A2 (TxA2) and vascular prostacyclin (PGI2) production in newborn infants, the stable metabolites of these prostanoids, thromboxane B2 (TxB2) and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), respectively, were studied in 48 hyperbilirubinemic (serum total bilirubin concentrations between 100 and 320 mumol/1) term infants before and after phototherapy at the age of 2-10 days. The effect of bilirubin on platelet TxA2 production was also determined in vitro. The production of TxB2 during spontaneous clotting in infants with moderate hyperbilirubinemia (serum total bilirubin 171-250 mumol/1) was higher than that in infants with mild (serum bilirubin 100-170 mumol/1) or marked (serum bilirubin greater than 250 mumol/1) jaundice. There was, in addition, an inverse correlation (r = -0.625, p less than 0.01, n = 20) between TxB2 formation and serum total bilirubin concentrations in infants with total bilirubin concentrations over 170 mumol/1. Platelet TxB2 production was enhanced at low (200 mumol/1), but decreased at high (400-1600 mumol/1) concentrations of bilirubin in vitro. Although phototherapy reduced the serum bilirubin levels, it did not change the TxB2 generation. Neither hyperbilirubinemia nor phototherapy had any effect on the plasma 6-keto-PGF1 alpha levels. The results indicate a dual effect of bilirubin on the TxA2 production in neonatal platelets. This may contribute to the hemostatic disturbances in neonatal hyperbilirubinemia.

Thromboxane B2 production by fetal and neonatal platelets: effect of idiopathic respiratory distress syndrome and birth asphyxia

To study the production of proaggregatory thromboxane A2 (TxA2) by fetal and neonatal platelets, blood specimens were collected from umbilical cords immediately after delivery at term (n = 22), from newborn infants during the first 10 days of life (n = 85), from infants between 1 and 3 months of age (n = 14), and from healthy adults (n = 18). The blood samples were allowed to clot spontaneously at +37 degrees C for 60 min, and the concentrations of thromboxane B2 (TxB2), a stable metabolite of TxA2, in the sera were measured by radioimmunoassay and expressed as nanograms of TxB2/10(6) platelets. Platelet TxB2 generation in term infants at the age of 1 day (1.344 +/- 0.253 ng/10(6) platelets, mean +/- SE, n = 9) was higher than that in cord blood (0.634 +/- 0.042 ng/10(6) platelets, n = 22), or in infants of 1-3 months of age (0.881 +/- 0.099 ng/10(6) platelets, n = 14), or in adults (0.869 +/- 0.062 ng/10(6) platelets, n = 18). Increase in TxB2 generation following birth was seen already at the age of 1 h (1.076 +/- 0.114 ng/10(6) platelets, n = 9). TxB2 synthesis in preterm infants (1.032 +/- 0.136 ng/10(6) platelets, n = 10) did not differ from that in term infants on the 1st day of life, and idiopathic respiratory distress syndrome had no effect on it (1.029 +/- 0.079 ng/10(6) platelets, n = 19). Severe birth asphyxia was accompanied by reduced TxB2 formation (0.564 +/- 0.201 ng/10(6) platelets, n = 7).(ABSTRACT TRUNCATED AT 250 WORDS)

Early closure of patent ductus arteriosus with indomethacin in preterm infants with idiopathic respiratory distress syndrome

Thirty-seven preterm infants with idiopathic respiratory distress syndrome were prospectively studied for the effect of the early closure of patent ductus arteriosus with indomethacin on the course of idiopathic respiratory distress syndrome. Serial retrograde aortograms were performed in all infants in order to visualize the ductus arteriosus, apart from three patients, who died early and were evaluated aortographically only once. The ductus was initially open in 27 infants and closed in 10 infants. The infants with open ductus arteriosus were randomly divided into two groups. The first group consisted of 13 infants, in whom the ductus was closed with indomethacin at a median age of 18 hours. The other 14 infants served as controls. Total time on assisted ventilation and duration of exposure to additional oxygen were significantly shorter in medicated infants than in controls. Oxygenation of infants with an initially closed ductus was better from birth and duration of their ventilatory assistance and oxygen exposure were shorter than in infants with initial ductal shunting. The data suggest that the early closure of the patent ductus arteriosus with indomethacin in distressed preterm infants has a favourable effect on the course of idiopathic respiratory distress syndrome.

Increased plasma immunoreactive 6-keto-prostaglandin F1 alpha levels in newborns with idiopathic respiratory distress syndrome

Serial plasma concentrations of immunoreactive 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), the stable hydration product of prostacyclin (PGI2), were measured with radioimmunoassay during the first month of life in 25 preterm infants with idiopathic respiratory distress syndrome (IRDS) and 38 preterm controls with normal heart and lung function. The levels of 6-keto-PGF1 alpha (521 +/- 81 pg/ml, mean +/- S.E.) in the infants with IRDS were higher (P less than 0.05) than those in the controls (335 +/- 42 pg/ml) on the first day of life, but thereafter no difference was seen. The highest first day 6-keto-PGF1 alpha level (1448 pg/ml) was found in the infant who died because of severe IRDS at the age of 19 h. The plasma 6-keto-PGF1 alpha concentrations in the distressed infants correlated positively with the alveolar-arterial oxygen gradient and the need of additional oxygen, but negatively with the arterial pH. In addition, an inverse correlation between the first day concentrations of 6-keto-PGF1 alpha and the lowest arterial oxygen tension in infants needing assisted ventilation was found. The mode of delivery (Cesarean section versus vaginal delivery) the gestational age, birth weight, sex or Apgar scores of the infants were not related to the 6-keto-PGF1 alpha levels on the first day of life. Neither did maternal pre-eclampsia, diabetes mellitus, or antenatal glucocorticoid treatment have any effect on the 6-keto-PGF1 alpha concentrations in the newborns. Our data suggest that a surge of the vasodilatory and antiaggregatory PGI2 is released during the early stage of IRDS, possibly in an attempt to increase the pulmonary perfusion. Our results give further indirect evidence that hypoxia stimulates the PGI2 production. High plasma immunoreactive 6-keto-PGF1 alpha levels during the early phase of IRDS suggest an increased generation of the vasodilatory and antiaggregatory PGI2 in this syndrome. This may be an attempt to overcome the increased pulmonary vasconstriction in IRDS. When the PGI2 formation rapidly declines after the first day of life, a relative PGI2 deficiency may ensue.

Plasma prostacyclin from birth to adolescence

The plasma concentration of 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), the stable hydration product of prostacyclin, was measured by radioimmunoassay in 111 healthy children aged between 1 day and 16 years and in 21 healthy adults aged between 21 and 72 years. The 6-keto-PGF1 alpha levels in children up to age 16 years were higher than those in adults. During the first 4 days of life the plasma concentrations of 6-keto-PGF1 alpha in term infants were higher (P less than 0.05) than the respective levels in preterm infants. There was no difference between the 6-keto-PGF1 alpha levels measured simultaneously in umbilical arterial and peripheral venous plasma in 7 newborn infants. Maternal pre-eclampsia or epidural analgesia during labour, mode of delivery, birthweight, or sex of the infants were not related to the plasma 6-keto-PGF1 alpha levels on the first day of life. High levels of vasodilatory and anti-aggregatory prostacyclin during the first days of life may play a role in the postnatal adaptation of the circulation and platelet function.

Hemihypertrophy with unilateral folliculitis and acne

A case of congenital hemihypertrophy, right-sided folliculitis and acne in a 16-year-old boy is described. Except for hemihypertrophy and skin changes on the right side, no other abnormalities were found. A similar combination could not be found in the literature.