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Biomedical subjects

M Hallman

Publications and source records attributed to M Hallman.

At least 73 records · Page 4Linked to original sources
PubMed1995

Levels of SP-A-anti-SP-A immune complexes in neonatal respiratory distress syndrome correlate with subsequent development of bronchopulmonary dysplasia.

As part of a double-blind, randomized, placebo-controlled study of human surfactant therapy for neonatal respiratory distress syndrome (NRDS), we measured circulating immune complexes between surfactant protein-A and anti-surfactant protein-A antibodies (SAS). Plasma from almost all infants contained detectable immune complexes. Immune complex levels in surfactant-treated infants were comparable with those of placebo-treated controls. Despite the relatively small sample size, maximum SAS immune complex values between 2 and 4 weeks after birth correlated significantly with subsequent development of BPD. Levels of these immune complexes correlated with eventual BPD independently of, and more strongly than, gestational age and birth weight. Thus, plasma SAS immune complex measurements may be useful in analyzing the course and outcome of NRDS, in particular the likelihood of subsequent development of BPD. This assay may also help to identify infants at risk for BPD and to target preventative therapy to them.

Antigen-Antibody Complex↗
PubMed1995

Interleukin-1 receptor antagonist in the fetomaternal compartment.

Interleukin-1 (IL-1) is a major mediator in infections and inflammation. Interleukin-1 receptor antagonist (IL-1ra) opposes the actions of IL-1. IL-1ra is present in exceptionally high concentrations in third trimester amniotic fluid. We studied IL-1ra in amniotic fluid, fetal serum and newborn urine. The concentrations of IL-1ra in amniotic fluid at mid-trimester and at 25-41 gestational weeks were 6.6 +/- 0.5 ng/ml (n = 30) and 100 +/- 4 ng/ml (n = 202), respectively. At mid-trimester, amniotic fluid IL-1ra was not dependent on fetal gender, whereas during the third trimester IL-1ra was higher in female- than in male-bearing gestations. Urine of normal term newborns during the first day of life contained a very high concentration of IL-1ra (125 +/- 16 ng/ml, n = 50). Urinary concentration in female newborns was significantly higher than that in male newborns (202 +/- 19 ng/ml, n = 25 versus 49 +/- 14 ng/ml, n = 25). IL-1ra concentration in fetal serum at 22-36 gestational weeks was 0.50 +/- 0.07 ng/ml (n = 31) and at term 1.5 +/- 0.3 ng/ml (n = 17). Serum concentrations were not gender-dependent. The gender differences in IL-1ra concentrations may in part explain the lower susceptibility of female fetuses to infection.

Amniotic Fluid↗
PubMed1995

Closure of patent ductus arteriosus decreases pulmonary myeloperoxidase in premature infants with respiratory distress syndrome.

The aim of the study was to determine whether in premature infants with respiratory distress syndrome (RDS), an interrelationship existed between patent ductus arteriosus (PDA) and pulmonary neutrophil content. Thirteen premature infants with PDA (gestational age 26.9 +/- 2.4 weeks, birth weight 903 +/- 300 g) were pair-matched with infants without PDA (gestations age 27.1 +/- 2.5 weeks, birth weight 1,041 +/- 430 g) with regard to gestational age, birth weight and severity of RDS. The myeloperoxidase (MPO) contents of tracheal aspirates were analyzed before (age 2.8 +/- 1.7 days, MPO I) and after closure of PDA with indomethacin (5.5 +/- 1.9 days, MPO II), and at corresponding time points in controls (2.6 +/- 1.6 and 4.8 +/- 1.8 days). In PDA patients closure of PDA decreased MPO from 14.7 (range 2.1-27.4) to 4.6 (1.2-8.0) micrograms/mg protein (p = 0.0008), whereas in controls it remained unchanged: 5.4 (2.9-7.8) and 5.3 (2.9-7.8; p = 0.58). A significant difference existed in the change in MPO contents between the infants with PDA and the controls. In premature infants with RDS, closure of PDA decreases the neutrophil content of the lungs. The effect may be caused by closure of PDA as such, or by indomethacin. The high pulmonary neutrophil content in PDA may exacerbate inflammatory processes and contribute to the development of chronic pulmonary disease.

Birth Weight↗
PubMed1995

Prenatal dexamethasone and exogenous surfactant therapy: surface activity and surfactant components in airway specimens.

To explain some of the effects of prenatal glucocorticoid treatment on lung function, surfactant parameters in the airway specimens of ventilator-dependent preterm infants were analyzed. In this double-blind study, the mothers of these infants had received dexamethasone (DEX) or placebo prenatally. Human surfactant was given for the treatment of moderate to severe respiratory distress syndrome. Seventy-six preterm infants with mean gestational age of 29 wk and mean birth weight of 1137 g were studied. The concentrations of surfactant components in epithelial lining fluid (ELF) were analyzed, and the surface activity was measured using a pulsating bubble method. Prenatal DEX treatment increased the responsiveness to exogenous surfactant and decreased the severity of respiratory failure during the first day of life. The treatment had no effect on the concentrations of surfactant phospholipids that were generally high. Prenatal DEX treatment increased the association between phospholipid concentration in ELF and the degree of respiratory failure. Prenatal DEX improved the surface activity of surfactant isolated from airway specimens and tended to increase the ratio of surfactant protein A to phosphatidylcholine among recipients of exogenous surfactant. A subgroup of infants, offspring of mothers with severe hypertension had an abnormally low concentration of surfactant protein A and a poor outcome, despite prenatal DEX treatment or surfactant substitution. Prenatal DEX decreased the concentration of nonsedimentable proteins in ELF and decreased the inhibition of surface activity by these proteins. Our results indicate that improved surfactant function during the first day of life explains some of the beneficial pulmonary effects of prenatal glucocorticoid treatment in preterm infants who are ventilator-dependent.

Apoproteins↗
PubMed1994

Intravascular ultrasound characterization of thrombi of different composition.

An in vitro model was designed to test the hypothesis that thrombi of varying composition have different echogenic patterns. Thrombi were prepared in specially designed tubes, mounted on a holder that allows introduction of an intravascular ultrasound catheter rotated inside a subselective sheath. The thrombi were made by the addition of thrombin to whole blood, platelet-rich plasma, and to mixtures of whole blood and platelet-rich plasma with increasing concentration of whole blood relative to the volume of the mixture in the following ratios: 1:5, 2:5, 3:5 and 4:5. Sixty-six thrombi prepared from 11 blood samples of healthy subjects were studied and compared with control tubes filled with saline solution. Platelet-rich thrombi showed low echogenicity similar to saline solution. Whole blood thrombi appeared uniformly "speckled." Mixtures of whole blood and platelet-rich plasma showed a gradual increase in echogenicity with an increasing amount of whole blood in the mixture. Quantitative videodensitometry compared the gray scale intensity of each image relative to background saline. The mean value of echogenicity of platelet-rich thrombi was 0.9 +/- 1.2, and the mean value of whole blood thrombi was 13 +/- 5.3. Platelet-rich thrombi are echo-lucent, and the main echogenic reflectance of thrombi originates from red blood cells. The ultrasound intensity is in linear relation to the amount of red blood cells in the thrombus.

Adult↗
PubMed1994

Cytokines released by granulocytes and mononuclear cells stimulate amnion cell prostaglandin E2 production.

Preterm labor is associated with histologic chorioamnionitis and intraamniotic infection. Chorioamnionitis is characterized by infiltration of the fetal membranes by granulocytes. In intraamniotic infection, white cells accumulate in amniotic fluid. Granulocytes and mononuclear cells have been shown to release products that stimulate prostaglandin E2 (PGE2) production by amnion cells. The aim of the present study was to identify some of these products. Cell-free supernatant obtained from formylmethionyl-leucyl-phenylalanine (FMLP)-activated granulocytes was subjected to size exclusion chromatography. The fractions obtained were analyzed for their stimulatory effect on PGE2 production by human amnion cells in culture. Two peaks of PGE2-stimulatory activity were found. The activity present in one of these was synergistic with interleukin-1 beta (IL-1 beta) in stimulating amnion cell PGE2 production and was found to contain mainly transforming growth factor-alpha (TGF-alpha) immunoreactivity. This cytokine originated at least in part from eosinophils. The PGE2-stimulatory activity present in the other peak contained IL-1 beta, epidermal growth factor (EGF), and tumor necrosis factor-alpha (TNF-alpha). The release of IL-beta, TNF-alpha, TGF-alpha, and EGF by granulocytes differed from that of mononuclear cells. We have previously shown that TGF-alpha and EGF are synergistic with IL-1 and TNF-alpha in enhancing amnion cell PGE2 production. The different pattern of prostaglandin-stimulatory cytokines released from different types of white cells suggest that the cells may potentiate each others' effects.

Amnion↗
PubMed1994

Increased incidence of bronchopulmonary dysplasia after antenatal administration of indomethacin to prevent preterm labor.

The aim of this randomized study was to compare the neonatal outcome in infants who have been exposed in utero to indomethacin with that in infants exposed to a beta-adrenergic agonist, nylidrin hydrochloride. Eighty pregnant women threatened with preterm labor between 24 and 34 weeks of gestation were enrolled in the study. An intravenous infusion of nylidrin or enterally administered indomethacin was given for a maximum of 72 hours. If preterm labor recurred, all parturient patients were treated with nylidrin. Indomethacin prolonged gestation significantly more than the beta-adrenergic agonist (6.6 weeks vs 4.5 weeks; p = 0.04). Ten of the forty-two infants exposed to indomethacin and 2 of the 45 infants exposed to nylidrin had bronchopulmonary dysplasia (24% vs 5%; p = 0.02). Among the 28 infants delivered within 120 hours after the start of treatment, the incidences of respiratory distress syndrome (82% vs 29%; p = 0.02), bronchopulmonary dysplasia (73% vs 6%; p = 0.0006), and necrotizing enterocolitis or focal intestinal perforation (27% vs 0%; p = 0.03) were higher among those exposed to indomethacin than among those exposed to nylidrin. We infer that administration of indomethacin to pregnant women threatened with premature labor is associated with an increased risk of bronchopulmonary dysplasia in their infants if delivery occurs early.

Adult↗
PubMed1994

Free-radical-induced lipid peroxidation during the early neonatal period.

The effect of gestational age on postnatal free-radical-mediated lipid peroxidation was studied in 19 term (gestational age 37-42 weeks) and 21 healthy preterm (gestational age 31-36 weeks) infants by measurement of expired ethane and pentane during the first 7 days of life. Ethane (11.9 versus 5.7 pmol/kg/min; p = 0.0001) and pentane (11.4 versus 7.5 pmol/kg/min; p = 0.01) were significantly higher in preterm than in term infants. Correlations were found between gestational age and ethane (r = 0.60, p = 0.0001) for days 1-7 and pentane (r = 0.54, p = 0.0003) for days 3-7; and between birth weight and ethane (r = 0.58, p = 0.0001) and pentane (r = 0.55, p = 0.0003). These results indicate that during the postnatal period, immaturity is a major factor determining the rate of free-radial-mediated lipid peroxidation.

Age Factors↗
PubMed1994

Interaction of transferrin saturated with iron with lung surfactant in respiratory failure.

Proteins that decrease the surface activity of surfactant accumulate in epithelial lining fluid in respiratory failure. The aim of this study was to isolate a surfactant inhibitor from the airways of rabbits in acute respiratory failure induced by bronchoalveolar lavage (BAL). This inhibitor was identified as being transferrin (TF). Unlike serum TF, TF recovered in respiratory failure was saturated with iron (Fe(3+)-TF). Fe(3+)-TF decreased the surface activity of normal surfactant in vitro, whereas iron-free TF had no effect. In the presence of H2O2 and a reducing agent, Fe(+3)-TF inactivated the surfactant complex: the surface absorption rate was decreased, immunoreactive surfactant protein A was decreased, and malondialdehyde was formed. The acute effects of Fe(3+)-TF and iron-free TF applied to the airways were studied in animal models. In respiratory failure induced by BAL, Fe(3+)-TF deteriorated respiratory failure, whereas iron-free TF had no effect. In respiratory failure induced by hyperoxia for 48 h, administration of iron-free TF ameliorated the respiratory failure and improved the surface activity in BAL. We propose that Fe(3+)-TF accumulating in epithelial lining fluid during lung damage contributes to surfactant inhibition and promotes the formation of free radicals that inactivate the surfactant system.

Animals↗
PubMed1994

Influence of fetal gender on the concentration of interleukin-1 receptor antagonist in amniotic fluid and in newborn urine.

IL-1 receptor antagonist (IL-1ra) is a cytokine that blocks the effects of IL-1 by binding to IL-1 receptors without inducing signal transduction. Amniotic fluid contains high concentrations of IL-1ra. The purpose of this study was 1) to analyze whether factors related to the mother or the fetus influence amniotic fluid IL-1ra concentration, and 2) to study whether the fetus is a source of IL-1ra. Two hundred two specimens of amniotic fluid, as well as 21 urine samples from newborn infants, were analyzed. Women carrying a female fetus had a higher concentration of amniotic fluid IL-1ra than those carrying a male fetus (female 136.4 +/- 6.1 micrograms/L, n = 83; male 74.7 +/- 3.7 micrograms/L, n = 119; p < 0.0001, unpaired two-sided t test). Length of gestation, presence or absence of labor signs, or elevated IL-1 beta in amniotic fluid did not affect the concentration of IL-1ra in amniotic fluid. Urine of infants taken during the first 48 h of life contained a high concentration of IL-1ra (91.1 +/- 17.5 micrograms/L). The urinary IL-1ra concentration was higher in female newborns than in male newborns (females 124.0 +/- 25.2 micrograms/L, n = 11; males 54.9 +/- 19.1 micrograms/L, n = 10; p = 0.04). We conclude that 1) the concentration of IL-1ra in amniotic fluid and newborn urine is dependent on the gender of the fetus and of the newborn and 2) fetal urine is a major source of amniotic fluid IL-1ra.(ABSTRACT TRUNCATED AT 250 WORDS)

Amniotic Fluid↗
PubMed1994

Immaturity-dependent free radical activity in premature infants.

To examine the role of immaturity in the free radical-mediated rate of lipid peroxidation in premature infants, we studied 27 infants [gestational age, 27.1 (SD 2.4) wk; birth weight, 970 (SD 330) g]. Ethane and pentane were quantitated in expired air during the first 18 d of life. During the first 2 postnatal d ethane [24.1 (SEM 7.8) pmol x kg-1 x min-1] and pentane [24.2 (SEM 4.1) pmol x kg-1 x min-1] were stable but increased during d 5 to maxima of 79.1 (15.8) pmol x kg-1 x min-1 and 62.1 (8.1) pmol x kg-1 x min-1, respectively. Maximum ethane and pentane correlated with gestational age (r = -0.42, p = 0.03 and r = -0.52, p = 0.005, respectively) and birth weight (r = -0.38, p = 0.05 and r = -0.59, p = 0.001, respectively). Infants with high maximum expired ethane and pentane (exceeding 40 pmol x kg-1 x min-1) had higher odds of dying or having bronchopulmonary dysplasia than those with low ethane and pentane (odds ratio, 6.5; 95% confidence interval, 1.1 to 38.5; p < 0.05 for ethane and odds ratio, 5.6; 95% confidence interval, 1.1 to 29.3; p < 0.05 for pentane). We conclude that degree of prematurity is the single most important factor explaining free radical-mediated lipid peroxidation in premature infants. A therapeutic intervention to limit the effects of free radicals should be started during the 1st postnatal d in premature infants to be effective.

Ethane↗
PubMed1994

Dexamethasone treatment of infants at risk for chronic lung disease: surfactant components and inflammatory parameters in airway specimens.

The mechanisms explaining the beneficial effects of glucocorticoid in ventilator-dependent preterm infants are not known. In the present randomized trial, we evaluated the hypothesis that dexamethasone (DEX) treatment of small, preterm infants at risk for chronic lung disease favorably affects the surfactant system. Twenty-three ventilator-dependent infants, with a mean +/- SD gestational age of 26 +/- 2 wk and a mean birth weight of 836 +/- 173 g, received 1 wk of treatment with either DEX (dose 0.5 mg/kg/d) or placebo beginning at 2 wk of age. The airway specimens were analyzed for surfactant components, surface activity, surfactant inhibitors, and inflammatory mediators. The concentrations of these parameters in epithelial lining fluid were calculated using the urea method. DEX treatment decreased the concentration of nonsedimentable protein in epithelial lining fluid within 3 d (p < 0.05). The nonsedimentable fraction of airway specimens decreased the surface activity of surfactant as a function of protein concentration. At a constant protein concentration, the protein from placebo-treated infants inhibited the surface activity of human surfactant in vitro more than protein from DEX-treated infants (p < 0.05). DEX transiently increased the concentration of surfactant protein-A in epithelial lining fluid but had no effect on surface activity of the sedimentable surfactant complex or on concentrations of phosphatidylcholine, IL-1 beta, lactoferrin, or myeloperoxidase. We conclude that the acute beneficial effect of DEX treatment in preterm ventilator-dependent infants may in part be mediated through a decrease in the concentration of non-sedimentable protein and a decrease in the capacity of this protein to inhibit surface activity.

Blood Proteins↗
PubMed1994

Successful treatment of ARDS with two doses of synthetic surfactant.

A 50-year-old man with adult respiratory distress syndrome (ARDS) was successfully treated with synthetic surfactant. The therapy rapidly improved the respiratory function; it also increased the release of endogenous surfactant. Synthetic surfactant may thus be of value in the treatment of ARDS.

Drug Combinations↗
PubMed1994

The fate of exogenous surfactant in neonates with respiratory distress syndrome.

Respiratory distress syndrome (RDS) in newborn neonates is characterised by deficient secretion of surfactant from type III alveolar cells. Administration of surfactant to airways acutely decreases the degree of respiratory failure and increases the survival rate in neonates with RDS. Clinically available surfactants are lipid extracts derived from animal lung lavage or from whole lung. Synthetic surfactants contain phospholipids or additional spreading agents. An optimal exogenous surfactant would be efficacious, nontoxic and nonimmunogenic, resistant to oxidants and proteolytic agents, widely available at reasonable cost and manufactured with little batch-to-batch variability. Surfactant has been instilled into the airways as a bolus infusion through the endotracheal tube. In addition, surfactant may be given by aerosolisation or continuous infusion into the airways. Suggested dosages range from 50 to 200 mg/kg. Exogenous surfactant is cleared from the epithelial lining fluid (ELF) mainly by alveolar epithelial cells, although alveolar macrophages and the central airways may also contribute to clearance of the drug. Only small quantities of surfactant actually enter the blood stream. A significant fraction of surfactant is taken up, processed, and secreted back into the alveolar space by type II alveolar cells. This process is termed recycling. Phosphatidylglycerol, given to small premature neonates as a component of exogenous human surfactant, has an apparent pulmonary half-life of 31 +/- 3 hours (n = 11). The apparent pulmonary half-life of the main surfactant component dipalmitoyl phosphatidylcholine is 45 hours (n = 3) and that of surfactant protein A is about 9 hours (n = 4). A relationship between the dose of exogenous surfactant and its concentration in the ELF has been demonstrated. Some neonates with RDS respond poorly to surfactant therapy. The reasons for this include insufficient levels of surfactant in the ELF, uneven distribution of exogenous surfactant, inability of exogenous surfactant to enter the metabolic pathways, inhibition of surface activity by plasma-derived proteins, or inactivation of surfactant as a result of proteases, phospholipases, or oxygen free radicals. In addition, surfactant therapy may be ineffective in neonates with respiratory failure caused by factors other than surfactant deficiency. The efficacy of exogenous surfactant can be improved by increasing the dosage of surfactant and by administration of surfactant very early in respiratory failure.

Animals↗
PubMed1994

Prenatal dexamethasone treatment in conjunction with rescue therapy of human surfactant: a randomized placebo-controlled multicenter study.

OBJECTIVES: A placebo-controlled, randomized, double-blind study was performed to determine whether prenatal dexamethasone (DEX) treatment improves the outcome of the preterm infant when exogenous surfactant is available. METHODS: 157 pregnant women at five hospitals with threatened preterm delivery and with lengths of gestation < 32 weeks received either DEX (dose 6 mg four times at 12-hour intervals) or placebo (PL). Prenatal treatment was not repeated. Preterm infants received rescue therapy of human surfactant (maximum four doses) if they required ventilatory support and at least 40% oxygen for the treatment of respiratory distress syndrome (RDS). RESULTS: Enrolled pregnant women delivered 188 live-born neonates, of whom 79 (DEX 41 and PL 38 neonates) were born 1 to 14 days after the prenatal treatment. Neonates born within 1 to 14 days after the initial DEX treatment had a lower incidence of RDS (DEX, 44%; PL, 79%; P < .01), lower requirements of surfactant (DEX, 22%; PL, 53%; P < .01), shorter duration of ventilatory support (DEX, 2.0 days; PL, 5.3 days; P < .05) and oxygen therapy (DEX, 2.0 days; PL, 7.0 days; P < .01), and a higher neonatal survival without ventilatory support (P < .05) than PL-treated neonates. DEX-treated neonates had higher mean blood pressure than PL-treated neonates during the first 3 days after birth. Among all neonates treated with DEX, there was a lower incidence of intraventricular hemorrhage or periventricular leucomalacia (DEX, 13%; PL, 33%; P < .01). Reduction in the incidence of intraventricular hemorrhage or periventricular leucomalacia in DEX-treated neonates was particularly associated with exogenous human surfactant therapy (DEX+surfactant 10%; PL+surfactant 48%; P < .01). CONCLUSIONS: Prenatal DEX treatment combined with exogenous human surfactant therapy in preterm infants decreases pulmonary morbidity and cerebral complications, and increases survival without severe morbidity.

Cerebral Hemorrhage↗
PubMed1993

Bronchoalveolar lavage fluid findings following radiotherapy for non-small cell lung cancer.

PURPOSE: To evaluate the diagnostic potential of bronchoalveolar lavage fluid analysis in radiation-induced lung injury. METHODS AND MATERIALS: Thirty patients with inoperable non-small cell lung cancer received either high-dose hyperfractionated radiotherapy or radiotherapy and interferon, a potential radiosensitizer, or radiotherapy and N-acetylcysteine, a potential radioprotector. Bronchoalveolar lavages were performed before and immediately after radiotherapy, and thereafter 6-8 weeks and 3 months after radiotherapy. Total and differential cell counts were measured from the bronchoalveolar lavage fluid samples. Urea measured in serum and in bronchoalveolar lavage fluid was used to calculate epithelial lining fluid. The concentrations of protein and phosphatidylcholine, the major surfactant phospholipid, in epithelial lining fluid were measured. The extent of radiation-induced lung injury was assessed from computed tomographies performed before radiotherapy, and 6-8 weeks and 3 months after radiotherapy. RESULTS: More patients in the interferon-arm developed radiation pneumonitis than did patients in the other groups, but no significant differences in alveolar fluid indices were noted between the groups. When all the patients were studied together, radiation was shown to have induced a significant relative increase of lymphocytes in bronchoalveolar lavage fluid 6-8 weeks and 3 months after the end of radiotherapy. The concentration of phosphatidylcholine in epithelial lining fluid decreased significantly 6-8 weeks and 3 months after treatment. The increase in protein concentration in epithelial lining fluid reached a statistically significant level 6-8 weeks after radiotherapy. CONCLUSION: Analysis of bronchoalveolar lavage fluid predicts the degree of radiation pneumonitis; however, radiology remains to be "the gold standard."

Acetylcysteine↗
PubMed1993

Interleukin-1 binding and prostaglandin E2 synthesis by amnion cells in culture: regulation by tumor necrosis factor-alpha, transforming growth factor-beta, and interleukin-1 receptor antagonist.

Proinflammatory cytokines may promote preterm labor in the setting of intrauterine infection. Tumor necrosis factor (TNF) and interleukin-1 (IL-1) synergistically stimulate the production of prostaglandin E2 (PGE2) by amnion cells. Transforming growth factor-beta (TGF-beta) inhibits the cytokine-stimulated PGE2 production. In the present study, we investigated the binding of IL-1 beta on human amnion cells in culture. Untreated amnion cells possessed 540 +/- 60 IL-1 receptors per cell, with a dissociation constant of 1.4 +/- 0.4 nM. Cells treated with TGF-beta 1 (10 ng/ml) had 570 +/- 110 receptors per cell. TNF-alpha (50 ng/ml) increased the number of IL-1 receptors to 2930 +/- 590. TGF-beta 1 inhibited the receptor upregulation by TNF-alpha. Cells treated with TGF-beta 1 and TNF-alpha expressed 1140 +/- 590 receptors per cell. The binding affinity was not changed by the cytokines. IL-1 receptor antagonist (IL-1ra) inhibited the stimulation of amnion cell PGE2 production by IL-1 beta, but not by TNF-alpha. Amnion cells secreted large amounts of IL-1ra (1.1 +/- 0.3 ng/10(5) cells). Treatment of the cells with TGF-beta 1 or TNF-alpha did not affect the release of IL-1ra. We conclude that IL-1 receptor expression is an important step in the regulation of the effects of cytokines on amnion cell PGE2 production.

Amnion↗