Stable microbubble test for predicting the risk of respiratory distress syndrome: II. Prospective evaluation of the test on amniotic fluid and gastric aspirate

We determined prospectively if the stable microbubble (SM) test on gastric aspirate obtained at birth was as useful as that on amniotic fluid in predicting respiratory distress syndrome (RDS). One hundred and five paired samples of amniotic fluid obtained at delivery from 105 consecutive women with gestation of 35 weeks or less and gastric aspirates from their neonates obtained within 30 min of birth were studied. The SM test with the predefined cut-off value of less than 5 bubbles/mm2 for amniotic fluid and less than 10 bubbles/mm2 for gastric aspirate signified the risk of RDS with the positive predictive value of 100% and 96% and with the negative predictive value of 91% and 84%, respectively. We conclude that the SM test on both amniotic fluid and gastric aspirate obtained at birth is a rapid (< 10 min), simple and reliable procedure for predicting neonates who will develop RDS. It may be used as a bedside test to define a population of neonates with surfactant deficiency in clinical trials of prophylactic surfactant therapy.

Stable microbubble test for predicting the risk of respiratory distress syndrome: I. Comparisons with other predictors of fetal lung maturity in amniotic fluid

With the advent of surfactant replacement therapy, there is an increasing need for a rapid test of predicting the development of respiratory distress syndrome (RDS). We evaluated the clinical usefulness of the stable microbubble (SM) test in predicting the development of RDS by comparison with other tests in amniotic fluid samples obtained within 12 h before delivery from 40 pregnancies between 23-35 weeks of gestation. These tests included the lecithin/sphingomyelin (L/S) ratio, disaturated phosphatidylcholine/sphingomyelin (DSPC/S) ratio, concentrations of lecithin, DSPC, and surfactant-associated proteins A and B, C (SP-A, SP-B,C). The cut-off value of each test for predicting RDS was determined at a point of maximum diagnostic accuracy. The overall diagnostic accuracy of the SM test was similar to that of other tests. However, both the SM test and the SP-B,C concentration had positive predictive values of 100%. We conclude that the rapid (< 10 min) and reliable information obtained by this test should encourage its use in defining a population of neonates with surfactant deficiency in a multicentre trial of prophylactic surfactant therapy.

Neonatal adrenal hemorrhage detected antenatally

This report describes two cases of neonatal adrenal mass detected antenatally by routine ultrasound (US) examination of pregnant women. Case 1 was recognized by the fetal US at 31 weeks gestation. The mass, located near the right upper pole of the kidney, was echolucent on US examination. A serial US of the mass showed changes of the internal echoes from a cystic lesion to a mixed lesion, and finally to a hyperechogenic lesion due to a neonatal adrenal hemorrhage (NAH). At 33 days, laparotomy was performed, and the pathological finding revealed an NAH owing to the mass bleeding into the adrenal cyst. Case 2 was also detected by fetal US just before birth. The mass of the right upper pole of the kidney was hyperechogenic on US examination. The baby clinically deteriorated after birth because of hypovolemia owing to NAH. A serial US of the mass showed the change from a hyperechogenic to a cystic lesion. Four months later, the mass spontaneously resolved. From the US spectrum, the mass was diagnosed as NAH. These are the second known cases of NAH detected before birth in Japan.

Surfactant replacement therapy in premature babies with respiratory distress syndrome: factors affecting the response to surfactant and comparison of outcome from 1982-86 and 1987-91

The impact of surfactant therapy on chronic lung disease remains uncertain. During the past decade (1982-91), over 300 babies with respiratory distress syndrome (RDS) weighing 501-2,500 g at birth were consecutively treated with surfactant-TA at our neonatal intensive care unit. Data on 95 RDS babies treated in the first 5 year period (Period 1, 1982-86) were compared with those on 158 RDS babies treated in the second 5 year period (Period 2, 1987-91). Overall respiratory improvement was better in Period 2 than in Period 1. In Period 2, surfactant therapy converted 98% of the babies with moderate/severe RDS to those with 'near normal' lung by 72 hr post-treatment. In Period 2, 95% of the surfactant-treated babies weighing 501-1,750 g at birth survived, 97% of which required no supplemental oxygen at 40 weeks corrected gestational age. Increased survival rate in the surfactant-treated babies during the past decade has not been followed by a parallel increase in chronic lung disease. The severity of the initial pulmonary disease per se was not the significant risk factor for chronic lung disease. Several other variables affecting the response to surfactant therapy and outcome have been identified by stepwise logistic regression analysis and include factors related to perinatal events such as birth asphyxia and infection, and other complications of prematurity.

A prospective, randomized trial of early versus late administration of a single dose of surfactant-TA

Thirty-two neonates weighing 500-1500 g with documented surfactant deficiency and without evidence of severe birth asphyxia, infection, prolonged rupture of membranes greater than or equal to 72 h, or oligohydramnios were randomly assigned to receive a single intratracheal dose of surfactant-TA (100 mg/kg) either within 30 min of birth (n = 16, early group) or at 6 h of age (n = 16, late group). By 6 h of age, all neonates of the late group had moderate/severe RDS, while none of the neonates of the early group had either clinical or radiological respiratory distress syndrome. The incidence of bronchopulmonary dysplasia was significantly lower in survivors of the early group than those of the late group (1/15 versus 7/14, a 43% reduction with a 95% confidence interval of 14-72%, P = 0.025). These beneficial effects of early surfactant treatment remained after controlling for the various confounding factors in the logistic models.

Surfactant proteins and anti-surfactant antibodies in sera from infants with respiratory distress syndrome with and without surfactant treatment

The presence of surfactant protein antigenemia and of surfactant protein antibodies was determined in serum from surfactant-treated and control infants with respiratory distress syndrome who were enrolled in a prospective randomized clinical trial. The surfactant used for treatment (surfactant TA) contained surfactant proteins (SPs) B and C and no SP-A. Enzyme-linked immunosorbent assays (ELISAs) that identify surfactant-associated proteins and ELISAs that identify IgG or IgM directed against surfactant proteins were used to investigate sera from these infants obtained prior to treatment, at 1 week of age, and at 2 months of age. There were no significant differences between average values in the surfactant-treated and control groups at each time period. However, in the control group, averaged results from ELISAs that identify SP-A and that identify IgM antibodies to SP-A or to SP-B, C showed significant differences between pretreatment sera and sera obtained at 1 week of age. No significant differences were noted in averaged results for IgG. Positive ELISA values were more frequently found in the control group than in the surfactant-treated group with regard to SP-A, and IgM against SP-A and SP-B, C in sera from neonates at 1 week of age. No positive ELISA values were found in sera from infants at 2 months of age. It is concluded that some patients with severe respiratory distress syndrome presumably leak surfactant proteins into the circulation and that this induces transient low titers of IgM antibody. This occurrence is decreased with surfactant treatment. Surfactant treatment may reduce leak of surfactant proteins into the vascular space by reducing lung damage.

Precision and reliability of stable microbubble test as a predictor of respiratory distress syndrome

The precision and reliability of the stable microbubble test as a predictor of respiratory distress syndrome (RDS) were studied. In blind experiments, the stable microbubble test was performed by three analysts in quadruplicate on six different amniotic fluid samples obtained from pregnant women whose babies developed RDS and on three samples prepared from mature controls. Three-way analysis of variance revealed that there were statistically significant differential effects of the analyst, observer, and sampling on the stable microbubble values, and also that there were statistically significant interactions between the analyst and observer as well as between the analyst and sampling. However, the magnitude of these effects was not large enough to modify the interpretation of the test results. We conclude that the rapidity, simplicity and reliability of the stable microbubble test allow for its use as a bedside procedure in identifying infants who are likely to develop RDS.

[Factors affecting clinical response to surfactant therapy in neonates with severe respiratory distress syndrome]

Clinical data from a multicenter, nonrandomized clinical trial (phase II) of surfactant therapy in 206 neonates with severe respiratory distress syndrome were evaluated by logistic risk models to identify factors that might affect response to surfactant therapy as well as outcome. Based on the magnitude and duration of initial response to a single post-ventilatory dose of Surfactant-TA, the response patterns were classified into three categories: A) immediate and sustained response, B) immediate response, relapse, and recovery, and C) poor or no response. Neonates with response A had significantly better outcome than those with response C. When the neonates with response A were combined with those with response B, surfactant treatment was successful in 89% of the neonates, with a 90% survival rate in this series. The risk variables strongly associated with "non responders" were low pretreatment values for arterial pH (less than or equal to 7.25), blood pressure, and a 5-minute Apgar score (less than or equal to 6). All of these factors are known to be related to perinatal events including an intercurrent episode of hypoxia during the first hours of life, and modify the course of "pure" respiratory distress syndrome, in which the surfactant deficiency is the primary factor. Some of these factors affecting the response to the surfactant can be eliminated by improving perinatal care including maternal transport, prevention of birth asphyxia and initial stabilization of the neonates with respect to the cardiocirculatory system, and by treating with surfactant at or soon after birth.

Surfactant replacement therapy with a single postventilatory dose of a reconstituted bovine surfactant in preterm neonates with respiratory distress syndrome: final analysis of a multicenter, double-blind, randomized trial and comparison with similar trials. The Surfactant-TA Study Group

The effects of a single dose of surfactant TA were assessed in premature neonates (birth weight 750 to 1749 g) with respiratory distress syndrome (RDS) in a multicenter, double-blind, randomized clinical trial. Only neonates with surfactant deficiency and without ultrasonographic evidence of intracranial hemorrhage greater than or equal to grade II were enrolled. Fifty-four patients received surfactant (100 mg of phospholipid per kilogram of body weight) and 46 patients received an air placebo within 8 hours of life. Treatment with this surfactant resulted in a significant reduction in the severity of RDS with a concomitant increase in the proportion of neonates with mild disease. The frequency of pulmonary interstitial emphysema and of pneumothorax was significantly lower in treated neonates compared with control neonates (2% vs 26%, P = .0008, and 7% vs 39%, P = .0004, respectively). The frequency of intracranial hemorrhage was significantly lower in the surfactant group compared with the control group (20% vs 54%, P = .0008) and was also reduced for the smallest neonates in the surfactant group (13% vs 73%, P = .00008). When categorized according to severity of intracranial hemorrhage and severity of bronchopulmonary dysplasia, the surfactant group was at a significant advantage (adjusted Cochran-Mantel-Haenszel X2 = 10.72, P less than .001 and X2 = 4.43, P = .036, respectively). The proportion of neonates surviving without intracranial hemorrhage and/or bronchopulmonary dysplasia was 63% in the surfactant group vs 26% in the control group (P = .0004); as for the smallest neonates, it was 58% in the surfactant group vs 4% in the control group (P = .0002). There were no differences between the groups with respect to the frequency of patent ductus arteriosus (46% vs 37%), pulmonary hemorrhage (6% vs 7%), necrotizing enterocolitis (0% vs 2%), sepsis (4% vs 2%), retinopathy of prematurity (13% vs 22%), or death (15% vs 22%). It is concluded that treatment with the single-dose surfactant regimen used in this study reduces the severity of respiratory distress during the 48 hours after treatment and decreases the major pulmonary morbidity and intracranial hemorrhage in premature neonates with RDS. Further studies are needed to determine whether (1) treatment at birth or as soon as after RDS is diagnosed and (2) the use of multiple dose of this surfactant would result in any additional benefits.

Monozygous double inner cell masses in mouse blastocysts following fertilization in vitro and in vivo

The incidence of human identical twins after in vitro fertilization and embryo transfer (IVF-ET) is estimated to be higher than the commonly accepted incidence after conception in vivo. This paper reports that 8 mouse blastocysts which had double inner cell masses in 261 blastocysts (3.1%) were identified after fertilization in vitro and they developed into trophoblastic outgrowth formation with two inner cell masses. In contrast, only 3 monozygous double inner cell masses were observed in 526 blastocysts (0.6%) which were fertilized in vivo and cultured from the two-cell stage in vitro. It is therefore possible that fertilization in vitro predisposes to monozygous twinning.

Effects of indomethacin, prostaglandin E2 and prostaglandin F2 alpha on mouse blastocyst attachment and trophoblastic outgrowth in vitro

A study was performed in order to investigate the participation of prostaglandins (PGs) during implantation. The effects of indomethacin on mouse blastocyst attachment and trophoblastic outgrowth were examined in vitro. Studies were also carried out on cultures supplemented with PGE2 and/or PGF2 alpha along with indomethacin. (1) Blastocyst attachment and trophoblastic outgrowth were inhibited by indomethacin dose-dependency. (2) In the cultures supplemented with indomethacin and PGE2 or PGF2 alpha, respectively, the inhibitory effects of indomethacin were reduced. (3) In the cultures supplemented with all three substances with treatment (1) and (2), inhibition of indomethacin was partially reversed, but still lower than control group without indomethacin. The above results indicate that both PGE2 and PGF2 alpha have a promoting effect on implantation, and PGF2 alpha was more effective than PGE2.

Surfactant-associated proteins in tracheal aspirates of infants with respiratory distress syndrome after surfactant therapy

We have developed enzyme-linked immunoassays (ELISAs) that measure major proteins that are associated with pulmonary surfactant. Using these ELISAs, we tested sequential tracheal aspirates from infants severely ill with respiratory distress syndrome (RDS) who had been treated either with exogenous surfactant or with placebo within 8 h of birth. On average, we found low concentrations of surfactant proteins in tracheal aspirates on Day 1 of life, with increases evident by Day 3. The surfactant used in this study (TA surfactant) contains only the low molecular weight (6 kDa) surfactant proteins and not the 35 kDa surfactant protein. As we expected, those who were treated with TA surfactant more frequently had detectable concentrations of low molecular weight surfactant protein on the second day of life when compared with control infants. No differences were evident in the concentrations of surfactant proteins between the 2 groups by Day 3, nor were differences evident between the 2 groups evident for 35 kDa surfactant protein during the first 3 days of life. Increased low molecular weight surfactant proteins in tracheal aspirates 1 to 2 days after surfactant therapy may occur either because of persistence of exogenous surfactant proteins and/or enhanced surfactant protein production. Comparisons with measurements from other groups of patients with RDS confirm that absence of both surfactant proteins reflects alveolar surfactant deficiency.

[Pharmacokinetic and clinical studies on latamoxef in the field of obstetrics and gynecology]

Latamoxef (LMOX) 1 g was administered twice daily for 5 days to patients undergoing operation for myoma uteri and the time course of tissue concentrations of the drug and the prophylactic effect of the treatment on postoperative infection were studied. 1. Area under concentration-time curve (AUC) of LMOX was the highest in the perimetrium (45.3%), followed by the cervix uteri (39.2%), endometrium (35.9%), oviduct (35.1%), myometrium (29.5%), and ovary (24.4%). 2. Cmax was the highest in oviduct (46.9 micrograms/g), followed by Cmax's in perimetrium (44.2 micrograms/g), cervix uteri (35.8 micrograms/g), myometrium (26.9 micrograms/g), endometrium (25.6 micrograms/g), and ovary (24.3 micrograms/g). 3. Serum half-lives were T1/2(alpha) = 0.27 hour and T1/2(beta) = 1.81 hours. 4. Prophylactic efficacy against postoperative infections was 94.3%, and febrile morbidity was 5.7%. The preoperative and postoperative laboratory tests did not show appreciable changes, no adverse reaction was observed. In the present study, LMOX showed good transfer into gynecological tissues, suggesting its very high usefulness in the treatment of infection and in the postoperative management.