Fit-for-Discharge Criteria after Esophagectomy: An International Expert Delphi Consensus

There are no internationally recognized criteria available to determine preparedness for hospital discharge after esophagectomy. This study aims to achieve international consensus using Delphi methodology. The expert panel consisted of 40 esophageal surgeons spanning 16 countries and 4 continents. During a 3-round, web-based Delphi process, experts voted for discharge criteria using 5-point Likert scales. Data were analyzed using descriptive statistics. Consensus was reached if agreement was ≥75% in round 3. Consensus was achieved for the following basic criteria: nutritional requirements are met by oral intake of at least liquids with optional supplementary nutrition via jejunal feeding tube. The patient should have passed flatus and does not require oxygen during mobilization or at rest. Central venous catheters should be removed. Adequate analgesia at rest and during mobilization is achieved using both oral opioid and non-opioid analgesics. All vital signs should be normal unless abnormal preoperatively. Inflammatory parameters should be trending down and close to normal (leucocyte count ≤12G/l and C-reactive protein ≤80 mg/dl). This multinational Delphi survey represents the first expert-led process for consensus criteria to determine 'fit-for-discharge' status after esophagectomy. Results of this Delphi survey may be applied to clinical outcomes research as an objective measure of short-term recovery. Furthermore, standardized endpoints identified through this process may be used in clinical practice to guide decisions regarding patient discharge and may help to reduce the risk of premature discharge or prolonged admission.

Mast cells decrease efficacy of anti-angiogenic therapy by secreting matrix-degrading granzyme B

Resistance towards VEGF-centered anti-angiogenic therapy still represents a substantial clinical challenge. We report here that mast cells alter the proliferative and organizational state of endothelial cells which reduces the efficacy of anti-angiogenic therapy. Consequently, absence of mast cells sensitizes tumor vessels for anti-angiogenic therapy in different tumor models. Mechanistically, anti-angiogenic therapy only initially reduces tumor vessel proliferation, however, this treatment effect was abrogated over time as a result of mast cell-mediated restimulation of angiogenesis. We show that mast cells secrete increased amounts of granzyme b upon therapy, which mobilizes pro-angiogenic laminin- and vitronectin-bound FGF-1 and GM-CSF from the tumor matrix. In addition, mast cells also diminish efficacy of anti-angiogenic therapy by secretion of FGF-2. These pro-angiogenic factors act beside the targeted VEGFA–VEGFR2-axis and reinduce endothelial cell proliferation and angiogenesis despite the presence of anti-angiogenic therapy. Importantly, inhibition of mast cell degranulation with cromolyn is able to improve efficacy of anti-angiogenic therapy. Thus, concomitant mast cell-targeting might lead to improved efficacy of anti-angiogenic therapy.

Resistance towards VEGF-centered anti-angiogenic therapy is an important clinical challenge. Here, the authors show that mast cells mediate resistance to anti-angiogenetic inhibitors by altering the proliferative and organizational state of endothelial cells through mobilization of FGF-1 and GM-CSF from the tumor matrix and secretion of FGF-2.

[Postnatal changes in the ductus arteriosus and brown adipose tissue: a review and an exploratory post-mortem study of lambs]

After a short review of the literature, postnatal changes in the ductus arteriosus Botalli are described in 52 lambs sampled in 1970 and 1971. Five groups of animals were formed on the basis of findings. (I) All lambs (n = 18) that died of asphyxia or prematurity had open ducti and, in most cases, severe adventitial bleeding (2). Completely anatomically closed ducti were found in I-week-old lambs (n = 9). Lambs that died within about 4 days of birth were grouped as (3) low-birth weight (dysmaturity) (n = 2), (4) normal weight and died after bacterial infection (n = 7), or (5) normal birth weight and died of other causes (n = 6). The dysmature lambs died because of cold and poor suckling. Compared with the lambs with a normal body weight, the dysmature lambs had almost completely closed ducti. Extensive, often circular, haemorrhages at the periphery of the necrotic muscular tissue of the ductal media were found in the dysmature and infected lambs. In these lambs, the brown adipose tissue surrounding the ductus was red-brownish and often depleted of its fat. This fat depletion and haemorrhages were less severe in lambs that died of other causes. The haemorrhages in the media of the ductus arteriosus, which were not found in older lambs, have not been described previously in other species, including humans. These haemorrhages are most likely the result of a short period of ductal relaxation, resulting in the passage of blood through the vasa vasorum and leakage of blood cells from degenerated capillaries at the border of the necrotic muscular tissue. It is hypothesized that the relaxation results from one or a combination of the following: (i) direct heat from heat-producing brown adipose tissue surrounding the ductus (because of cold or infection), (2) infection or inflammatory mediators, and (3) adipose tissue-derived relaxing factors.

Drainage of esophageal leakage using endoscopic vacuum therapy: a prospective pilot study

BACKGROUND AND STUDY AIMS

Major leakage from an esophageal anastomosis is a life-threatening surgical complication. Endoscopically guided endoluminal vacuum therapy using polyurethane sponges is a new method for treating such leakage.

PATIENTS AND METHODS

Between June 2007 and June 2009, five patients (mean age 68 years) who developed anastomotic leakage after esophageal surgery were prospectively evaluated. After endoscopic diagnosis of a major leakage, polyurethane sponges were endoscopically positioned in the wound cavity of the anastomosis. Continuous suction was applied via drainage tubes fixed to the sponges. Initially sponges were endoscopically changed three times per week.

RESULTS

In all five patients treatment was successful. Median time to reduce levels of inflammation markers by 50 % was 10 days for white blood cell (WBC) count and 7 days for C-reactive protein (CRP). The smallest initial wound cavity size was 42 cm (3) and the largest was 157 cm (3). The median duration of drainage was 28 days, with a median of 9 sponge changes and a median time to total cavity closure of 42 days. Two patients needed anastomotic dilation by Savary-Miller bougienage due to stenosis found on further follow-up. One of these patients died of acute severe hemorrhage from an aortoanastomotic fistula after the dilation procedure.

CONCLUSIONS

Endoscopically assisted vacuum therapy is a well-tolerated and effective therapeutic option for treatment of major esophageal leaks after surgery. Additional surgery was avoided in all cases. However, the occurrence of a delayed aortoesophageal fistula calls for careful further investigation of this new technique.

Evaluation of the blood analyzer ABL 735 radiometer for determination of the percentage of fetal hemoglobin in fetal and neonatal blood

OBJECTIVE

To evaluate the quality of measurements of percentage fetal hemoglobin (HbF) using the blood analyzer ABL 735 and to compare the results with the HbF measurements using the Biorad-Variant (the gold standard).

METHODS

The percentage of HbF in fetal blood, obtained during intrauterine transfusions or from the umbilical cord blood of preterm and term babies, and from the red blood cells of adults who had given blood for transfusion, was determined spectrophotometrically (ABL-735) and by high pressure liquid chromatography (Biorad-Variant). Blood pH values were also measured with the ABL 735. Reproducibility (mean difference between duplo measurements) and the relationships between the HbF percentages measured by both methods were calculated.

RESULTS

Reproducibility was independent of the HbF percentage and was more reliable with the Biorad-Variant method (0.3%) than with the ABL-735 method (2.1%). Regression analysis showed that the ABL-HbF percentages were often underestimated. Serious aberrations were observed at low pH values (<7.00) on the recalculated ABL-HbF percentages. For samples with pHs >7.00 a relatively good relationship was found between the pH-corrected ABL-HbF percentages and those of the Biorad-Variant values.

CONCLUSION

The HbF percentage measured with the ABL blood analyzer is only moderately accurate if the HbF percentage is corrected for the pH.

Effect of tibolone on breast cancer recurrence: LIBERATE trial bone sub-study

Abstract #66

LIBERATE, a randomized, placebo controlled, double blind trial studied the effect of tibolone (Livial), a tissue selective hormone replacement therapy (HRT) on breast cancer (BC) recurrence, aiming to demonstrate non-inferiority of treatment compared to placebo. In the LIFT trial of osteoporotic women, tibolone prevented BC development.&#x2028; Design and Method: Women with surgically treated BC (T1-3, N0-2, M0) within the last 5 years complaining of vasomotor symptoms, were randomly assigned to tibolone 2.5mg daily or placebo treatment for a maximum of 5 years. Adequate sample size was estimated to be &gt;1500 in each arm. A bone mineral density (BMD) sub-study of 724 patients (454 Caucasian; 270 Asian) was enrolled utilizing DXA scanning at baseline and 2 years.&#x2028; Results: Between 2002 and 2004, 3,148 women were randomized in 31 countries; 1579 to tibolone and 1569 to placebo. Mean age at randomization was 52.7 years (28.0-75.0) and mean time since surgery was 2.1 years. In total 58% of women recruited were node positive and 78% ER positive. The trial closed prematurely in July 2007, with a median follow-up of 3.1 years (0.01-4.99) per patient, because an increased risk of BC recurrence occurred on tibolone HR 1.40 (1.14-1.70; p&lt;0.001); 15.2% (237/1556) women on tibolone recurred compared to 10.7% (165/1542) on placebo. Risk for distant recurrence on tibolone was HR 1.38 (95% CI 1.09-1.74 p=0.007).&#x2028; Aromatase inhibitor (AI) users had the highest risk of recurrence on tibolone HR 2.42 (1.01-5.79) compared to tamoxifen treated women HR 1.25 (0.98-1.59). Compared to ER positive cancers HR 1.56 (1.22-2.01), ER negative cancer had no increased risk of recurrence HR 1.15 (0.73-1.80). No differences in mortality occurred between groups.&#x2028; At entry to the bone sub-study, 298 (43%) women had normal BMD, 313 (45%) osteopenia (T-score between -1 and -2.5) and 81 (11.7%) osteoporosis. Low body mass index (&lt;0.001), Asian race (p&lt;0.001) and old age at menarche predicted for low bone mass after 2 years. Tibolone increased BMD by 3.5% at the lumbar spine and 2.9% at the hip compared to placebo (both p&lt;0.001) and reduced fracture rate in the Caucasian (p=0.036) but not the Asian population. Women with normal BMD (before or at day 1) had increased recurrence on tibolone 15.1% (21/139) compared to placebo 6.9% (11/159) p=0.036, whereas no increased BC recurrence was seen in women with low BMD; 7.5% (15/201) on tibolone and 6.7% (13/193) on placebo.&#x2028; Conclusion: HRT after breast cancer treatment increases BC recurrence especially in AI treated patients. Risk of BC recurrence is elevated in BC women with normal BMD (compared to low) who take HRT.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 66.

Safety of tibolone in the treatment of vasomotor symptoms in breast cancer patients--design and baseline data 'LIBERATE' trial

Many patients with a history of breast cancer (BC) will suffer from vasomotor symptoms, which can be induced or exacerbated by treatment with tamoxifen or aromatase inhibitors. The LIBERATE trial was designed as a randomized, double-blind, multicenter trial to demonstrate that tibolone 2.5mg/day (Livial) is non-inferior to placebo regarding BC recurrence in women with vasomotor symptoms surgically treated for primary BC within the last 5 years. Secondary objectives are effects on vasomotor symptoms as well as overall survival, bone mineral density and health-related quality of life. Mean age at randomization was 52.6 years, and the mean time since surgery was 2.1 years. The mean daily number of hot flushes and sweating episodes was 7.3 and 6.1, respectively. For the primary tumor, Stage IIA or higher was reported for >70% of the patients. In subjects whose receptor status was known, 78.2% of the tumors were estrogen receptors positive. At randomization, tamoxifen was given to 66.2% of all patients and aromatase inhibitors to 7%. Chemotherapy was reported by 5% at randomization. The adjuvant tamoxifen use in LIBERATE allows a comparison with the Stockholm trial (showing no risk of BC recurrence associated with hormone therapy), which was stopped prematurely subsequent to HABITS. The LIBERATE trial is the largest, ongoing, well-controlled study for treatment of vasomotor symptoms in BC patients.

TRAIL promotes metastasis of human pancreatic ductal adenocarcinoma

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has attracted considerable attention for its potential use in tumor therapy, as some recombinant variants of this ligand induce apoptosis in tumor cells without harming most normal cells. Here, we show that TRAIL strongly induces the expression of the proinflammatory cytokines interleukin-8 and monocyte chemoattractant protein 1 and enhances the invasion of apoptosis-resistant pancreatic ductal adenocarcinoma cells in vitro by upregulation of the urokinase-type plasminogen activator expression. Most importantly, we also demonstrate for the first time that TRAIL treatment results in strongly increased distant metastasis of pancreatic tumors in vivo. We orthotopically transplanted human pancreatic ductal adenocarcinoma cells to the pancreata of severe combined immunodeficiency mice and observed a dramatic increase in metastatic spread including a sixfold increase in the volume and fourfold increase in the number of liver metastases upon TRAIL treatment. Our results point to the necessity to carefully evaluate in vivo side effects of TRAIL and to select therapy conditions that not only enhance apoptosis induction but in addition prevent proinvasive and proinflammatory non-apoptotic TRAIL signaling.

Decreased deformability of donor red blood cells after intrauterine transfusion in the human fetus: possible reason for their reduced life span?

BACKGROUND

The life span of donor red blood cells (RBCs) is reduced in the fetus with Rh hemolytic disease. This may have resulted from donor or recipient factors.

STUDY DESIGN AND METHODS

Studied in vitro was the effect of gamma irradiation on hemolysis, methemo-globin (metHb), and lipid peroxidation of donor RBCs and the ability of fetal and adult plasma to protect irradiated RBCs from induced lipid peroxidation. Also studied in vivo were the effects after the time that donor RBCs reside in the fetus by measuring its lipid peroxidation, cholesterol-to-phospholipid ratios, and deformability of RBCs.

RESULTS

Irradiation barely increased hemolysis and metHb formation and did not increase lipid peroxidation. Plasma samples of D+ fetuses inhibited induced oxidative stress less than plasma samples of adults. Nevertheless, in vivo lipid peroxidation of the donor RBC membrane had not increased, whereas the molar cholesterol-to-phospholipid ratio increased from 1.08 +/- 0.11 to 1.38 +/- 0.12. It became identical to that of the fetal RBCs (1.44 +/- 0.12). Before transfusion, the deformability of the adult RBCs (elongation index, 0.578 +/- 0.013) was better than that of the fetal cells (elongation index, 0.494 +/- 0.027), but decreased to fetal levels after transfusion (elongation index, 0.518 +/- 0.039).

CONCLUSION

Irradiation of the RBCs and a reduced fetal antioxidant capacity do not lead to in vivo lipid peroxidation. The shorter life span of donor cells in the fetus probably results from a decreased deformability of the RBCs after transfusion, most likely owing to an increased cholesterol-to-phospholipid ratio.

Non-protein-bound iron and free radical damage in fetuses with rhesus haemolytic disease: influence of intrauterine transfusions

OBJECTIVE

To determine iron-induced free radical damage in fetal rhesus haemolytic disease (RHD) before and after repeated intrauterine red blood cell transfusions and its relation to hydrops fetalis.

DESIGN

Prospective, observational study.

SETTING

Department of Obstetrics, Leiden University Medical Centre, the Netherlands.

POPULATION

Fifty anaemic fetuses, including 13 hydropic ones, 9 preterm and 12 term neonates and 8 female non-pregnant adults.

METHODS

Venous blood plasma samples were collected from 50 fetuses suffering from RHD preliminary to the first, and if appropriate, subsequent intrauterine red blood cell transfusions for determination of iron status including non-protein-bound iron (NPBI) and iron-binding primary antioxidant proteins, total plasma anti-oxidant capacity and its contributing secondary antioxidants (e.g. vitamin C, uric acid, sulphydryl groups and peroxidation products). Results were compared with values of healthy preterm and term neonates directly at birth and adult controls. Within the fetal haemolytic group, 13 hydropic fetuses were analysed as a separate group.

MAIN OUTCOME MEASURES

Non-protein-bound iron, antioxidants, total antioxidant capacity and peroxidation products. Sub analysis of the outcome measures of the hydropic fetuses.

RESULTS

RHD fetuses had at initial cordocentesis a significantly higher NPBI level and a significantly lower total plasma antioxidant capacity than control babies and adults. Their vitamin C tended to be more oxidised but lipid peroxidation had not increased, when compared with preterm babies. The repeated intrauterine red blood cell transfusions had a positive effect on the total antioxidant capacity of plasma and did not increase the concentration of NPBI. The hydropic fetuses, who had higher NPBI concentrations and lower plasma protein concentrations and total antioxidant capacity, did not show more peroxidation products in plasma than the non-hydropic fetuses. Fetuses without reversal of hydrops despite intrauterine transfusions showed decreasing levels of proteins with subsequent transfusions but peroxidation products remained constant.

CONCLUSION

Repeated intrauterine red blood cell transfusions do not lead to free radical damage in the fetus in utero. Iron-induced free radical activity does not appear to play a causative role in the proceeding of hydrops fetalis in RHD.

Plasma guanosine 3',5'-cyclic monophosphate and severity of peri/intraventricular haemorrhage in the preterm newborn

A poorly controlled cerebral circulation, caused by excessive production of nitric oxide, has been suggested as predisposing to peri/intraventricular haemorrhage (PIVH) in the immature neonate. It is hypothesized that a relation exists between plasma cyclic GMP (cGMP) as an effector of endogenous vasodilatory nitric oxide production and severity of PIVH. In 83 consecutively admitted preterm neonates, nitric oxide production was assessed by measuring plasma cGMP at 0, 24, 48, 72 and 168 h of age. Simultaneously, cranial ultrasound investigations were performed and haemodynamic parameters registered. The investigations showed that 60 neonates (72%) had no PIVH; 18 neonates (22%) had mild to moderate PIVH; and 5 neonates (6%) had severe PIVH. At 48 and 72 h of age, cGMP levels of infants with severe PIVH were significantly higher than those of infants with no or only mild PIVH, whereas at 72 and at 168 h, infants with moderate PIVHs had significantly higher cyclic cGMP levels than infants without PIVH. Finally, at 168 h of age infants with mild PIVH also had higher cyclic cGMP values than those of infants without PIVH. Maximal cGMP values preceded the final extension of PIVH in moderate and severe PIVHs. Blood pressure support was necessary significantly more often in infants with moderate and severe PIVH. A logistic regression model revealed that cGMP was significantly associated with PIVH, irrespective of gestational age, mean arterial pressure or severity of infant respiratory distress syndrome.

CONCLUSION

Increased cGMP levels are associated with the development of PIVH. It is suggested that vasodilatory nitric oxide-induced impairment of cerebral autoregulation plays a role here.

A new method to determine the feto-placental volume based on dilution of fetal haemoglobin and an estimation of plasma fluid loss after intrauterine intravascular transfusion

OBJECTIVES

(1) To calculate the feto-placental volume (FPV), using the haematocrit (Ht) values and the percentages of fetal haemoglobin (HbF), before and after red blood cell transfusion. (2) To estimate the transfusion-induced loss of plasma fluid.

DESIGN

Retrospective analysis of data of 42 anaemic fetuses at the first transfusion [gestational age (GA) 19-36 weeks].

SETTING

Department of Obstetrics, Leiden University Medical Centre, The Netherlands.

SAMPLE

Fifteen hydropic and 27 non-hydropic fetuses.

METHODS

Donor blood volume (V(donor)) and Ht (Ht(donor)), fetal pre- and post-transfusion Ht values (Ht(initial), Htfinal) and percentages of HbF (HbF(initial) and HbF(final)) were used to calculate the FPV. The total red cell volume after transfusion (RCV(final)) and Ht(final) were used to estimate the plasma fluid loss.

MAIN OUTCOME MEASURES

Feto-placental blood volume and loss of plasma fluid.

RESULTS

The equations that use Htfinal over-estimate the FPV when the formula does not account for the difference between donor and post-transfusion Ht (FPV(Ht) = 21.36 * GA, - 390; r = 0.89). FPV is underestimated (FPV(Ht) = 9.90 * GA - 172; r = 0.84) when the blood volume increases with a volume less than the added donor blood volume. The calculation of FPV, using HbF percentages and the initial fetal RCV, is independent of volume changes (FPVHbF = 15.10 * GA - 279; r = 0.85). Comparing RCV(final) and Ht(final) values showed that 31.1 +/- 14.5% of the transfused volume was lost. Results of the hydropic fetuses did not differ from those of the non-hydropic fetuses.

CONCLUSIONS

FPV values based on Ht values are less reliable than those based on RCV and HbF findings. When, for practical reasons, Ht values have to be used, we propose an adapted equation for the calculation of the necessary volume of donor blood: V(donor) = FPV(HbF) * (Ht(final) - Ht(initial) / (Ht(donor) - 0.70 * Ht(final)).

Derivated fetal haemoglobin as a marker for red cell age in the human fetus reflecting stimulated or impaired red blood cell production

We have determined whether derivated fetal haemoglobin (dHbF, consisting of glycated and acetylated HbF) can be used as a cell age marker for fetal red blood cells (RBCs). Cord blood was obtained between 19 and 39 weeks of gestation from 28 alloimmunised anaemic fetuses (23 RhD+ and 5 Kell) and from 20 non-anaemic fetuses and newborns (controls). Density gradient centrifugation was applied to 36 samples (20 RhD+, 15 controls and 1 Kell) to obtain fractions of increasing cell age. Blood samples were used for measurements of mean cellular volume (MCV), mean cell haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), pyruvate kinase activity (PK) and derivated fetal haemoglobin (dHbF) by cation-exchange HPLC. Reticulocytes were counted only in the whole blood samples. In all density gradient separated RBC fractions, the values for MCV, MCH and PK activity decreased and those of MCHC and dHbF increased with increasing density (equivalent to increasing cell age). The mean density was lower for RBCs of the anaemic RHD group (1.072+/-0.007 g/ml) than for the non-anaemic controls (1.077+/-0.005 g/ml) (p<0.05) The RBC density of the Kell sensitised fetus did not differ from those of the controls. In the control group, the values of the cell age markers in whole blood changed significantly with the gestational age, showing an increase of mean age of the erythrocyte population. The best linear relationship was found for dHbF (y=6.28+0.17*weeks; r=0.84; p<0.001). In the anaemic RhD+ fetuses, the RBC age markers did not change with gestational age; the dHbF percentages were lower, and the MCV, MCH, PK values and the reticulocyte counts were higher than in the controls (0.05<p<0.001). The dHbF values of the Kell sensitised fetuses were above (p<0.01) and the reticulocyte counts were below normal (p<0.05) for gestational age. For the anaemic fetuses, a significant number of the dHbF values (86%) and of the reticulocyte counts (78%) differed from the values of the controls (p<0.01). The dHbF percentages in RhD+ fetuses showed the best correlation with the Hb deficit, which is a measure for anaemia (r=-0.81, p<0.0001). We conclude that the percentage derivated HbF may indicate whether the RBC production is normal for gestational age. It may in that sense reflect stimulated or impaired erythropoiesis in alloimmunised haemolytic anaemia.

Nitric oxide production during the early neonatal period in small-for-gestational-age infants

In a study of endogenous nitric oxide production in growth-retarded, very preterm newborns (<32 wk GA), urinary NOx/creatinine ratio and plasma guanosine 3',5'-cyclic monophosphate levels were determined during the early neonatal period. Newborns were divided into three groups: appropriate-for-gestational-age (AGA, n = 19), moderately small-for-gestational-age (SGA, n = 13) and severely SGA (n = 6) infants. Severely SGA infants showed significant higher values of nitric oxide derivatives during the first 24 h of life compared with the other groups.

CONCLUSION

An increased NO production is found in SGA infants during the first 24 h after birth. This may reflect an increased intrauterine nitric oxide production in the feto-placental circulation found in cases with intrauterine growth retardation,

Apparent rejuvenation of transfused donor blood in the fetus is due to accelerated removal of the older RBCs

BACKGROUND

In severely anemic fetuses of women alloimmunized to RBC antigens, transfused donor RBCs disappear faster than in adults. This may result from an accelerated linear or nonlinear decline with time. It was investigated whether changes in donor RBC age characteristics after circulation in the fetus may reflect the main type of cellular decline.

STUDY DESIGN AND METHODS

Donor RBC age characteristics (density, mean cell volume [MCV], and mean cell Hb content [MCHC]) were determined before intrauterine transfusions. Density gradient centrifugation was used to obtain RBCs of different ages. The results from gradient centrifugation were used to calculate mean values for the density, MCV, and MCHC to be expected after the transfusion interval, assuming a linear decline in RBCs of 1 percent per day. Donor and fetal RBCs, taken just before the second transfusion, were separated by agglutination with IgM D MoAb. For these donor cells, the observed mean values for density, MCV, and MCHC were compared with the calculated, expected values (n = 12).

RESULTS

The mean +/- SD transfusion interval was 17.9 +/- 3.6 days. The Hb declined by 1.75 +/- 0.62 percent per day (n = 9). After the transfusion interval and contrary to the expected changes, cell density and MCHC decreased and MCV increased significantly (0. 001<p<0.02). This difference between actual and calculated values decreased with increasing intervals; for MCV, it was also associated with a greater decline in Hb per day (p<0.05).

CONCLUSION

All donor cells age during circulation in the fetus. However, after the transfusion interval, the donor RBC population remaining is apparently younger than the RBC population before transfusion. This results from a preferential disappearance of older donor RBCs and not from a linear loss of cells with time. The removal of older RBCs before the transfusion may increase the time between transfusions and thereby reduce the total number of transfusions required.

Evidence of endothelium involvement in the pathophysiology of hydrops fetalis?

A fetus with signs of hydrops is at high risk of intrauterine death. The pathophysiology of hydrops fetalis is still unclear. We found decreased concentrations of cyclic guanosine monophosphate in fetal plasma of alloimmunized pregnancies complicated by hydrops fetalis, which might suggest reduced nitric oxide production due to injury of fetal vascular endothelial cells.

Amniotic fluid nitric oxide metabolites, cyclic guanosine 3',5' monophosphate and dimethylarginine in alloimmunized pregnancies

OBJECTIVE

To determine the relationship between gestational age or the Liley index (the severity of fetal hemolysis) and the amniotic fluid total nitrite (NOx), cyclic guanosine 3',5 'monophosphate (cGMP) and dimethylarginine (DMA) concentrations. We hypothesized that the concentrations of these components change because of fetal growth or adaptation to fetal anemia.

STUDY DESIGN

Amniotic fluids (n=64) were obtained between 23 and 37 weeks from fifty-three patients at risk for alloimmunization. Amniotic fluids from the pregnancies with a Liley index=1 were considered as controls (n=17). Creatinine (C, microMol) was determined with the Jaffé reagent, nitrite (NOx, microMol) with the Griess reagent, cGMP (nMol) by an enzyme immunoassay and DMA (microMol) after HPLC. Multiple regression analysis was used for separating the effects of growth and the estimated degree of anemia.

RESULTS

The concentration of NOx, cGMP and DMA was not related to the Liley index or whether or not the fetuses needed blood transfusions. The concentrations of creatinine (C), NOx and cGMP increased during pregnancy (in weeks;W) (C=-69.2+6.28W; r2=0.532; P<0.0001, NOx=-17.6+1.29W; r2=0.106; P=0.01, cGMP=-20.9+1.05W; r2=0.414; P<0.0001). The DMA concentration (3.8+/-0.8(SD) and the NOx/creatinine ratio (181+/-110 mM/M) did not change with gestational age. The cGMP/creatinine ratios (microM/M) increased (cGMP/C=-41.8+4.31W; r2=0.134; P=0.007) whereas the DMA/creatinine ratio (mM/M) declined during pregnancy (DMA/C=73.1-1.34W; r2=0.278; P=0.0002). Consequently, the NOx/DMA and cGMP/DMA ratios increased (NOx/DMA=-6.96+0.43W; r2=0.105; P=0.02, cGMP/DMA=-5.9+0.29W; r2=0.391; P<0.0001).

CONCLUSIONS

The concentrations in amniotic fluid of cGMP and NOX, but not of DMA increase during gestation. The cGMP/creatinine ratio increases also whereas that of DMA decreases. The changes in products of the NO-cGMP pathway are independent of mild to moderate fetal hemolysis and may result from fetal growth as well as from reduced inhibition of NO synthase by DMA. Gestational age related effects should be taken into account when analyzing nitric oxide metabolites in amniotic fluids.

Nitric oxide metabolites, cyclic guanosine 3,5 monophosphate and dimethylarginines during and after uncomplicated pregnancies: a longitudinal study

OBJECTIVE

In cross-sectional studies, the variability between women may mask or deny gestational changes, related to the nitric oxide-cyclic GMP system. Therefore, we analyzed longitudinally as markers of this system, the urinary levels of nitrite+nitrate (NOx), cyclic guanosine 3',5' monophosphate (cGMP) and of the inhibitor of nitric oxide synthase, dimethylarginine (DMA).

STUDY DESIGN

Late-afternoon urine samples were obtained from 20 women with uncomplicated pregnancies and nine non-pregnant women. Creatinine concentrations (mol) were determined with the Jaffé reagent and NOx (mmol) with the Griess reagent after reduction of nitrate. cGMP (micromol) was determined in an enzyme immunoassay and DMA (mmol) after solid-phase extraction and liquid chromatography. Trend analyses and (paired) t-tests were done for detection of time-related differences.

RESULTS

The NOx/creatinine (mmol/mol) ratios of the non pregnant women (63.8+/-18.8, S.D.) did not differ from those of the pregnant women at the onset of pregnancy (70.5+/-36.4). Over the entire pregnancy period these ratios declined significantly (P<0.001) and lower values were found at the end of gestation and after birth (49.6+/-22.4). The cGMP/creatinine (micromol/mol) and DMA/creatinine ratios (mmol/mol) changed parabolically (P<0.001). The maxima of 68.0+/-19.9 and of 4.95+/-1.01 were found at week 20 and 16, respectively. These ratios declined to 45.2+/-17.7 and to 4.03+/-0.83 at the end of gestation but not further during parturition (39.6+/-17.2 and 4.01+/-1.90). The lowest cGMP/creatinine ratios occurred one month after birth (27.4+/-15.7) while in the non-pregnant women the value was 15.3+/-6.2 microM/M. The lowest DMA/creatinine ratios, measured one month after birth (3.41+/-1.28 mmol/mol) were similar to those of the non-pregnant women (3.75+/-0.39 mmol/mol). Positive instead of negative relationships were found between the DMA results and those of the cGMP (P<0.001) and NOx determinations (P<0.05).

CONCLUSIONS

(1) The gestational changes of the urinary NOx/creatinine and especially of the GMP/creatinine ratio reflect most likely changes in vascular resistance. (2) Because of the variability of the results between but also within women, these ratios are useless to monitor supposed changes in NO production during parturition.

Cervicovaginal fetal fibronectin concentrations: predictive value of impending birth in postterm pregnancies

OBJECTIVE

To determine the predictive value of cervicovaginal fetal fibronectin (fFN) concentrations > or =50 ng/ml for spontaneous onset of labour within 3 days in pregnancies of 41 weeks gestation or more.

STUDY DESIGN

In the Department of Obstetrics, Leiden University Medical Centre, and of the Diaconessen Hospital, Voorburg (The Netherlands), 126 cervicovaginal secretions of fFN, from 80 consenting women between 287 and 304 days gestation were collected. Pregnant women underwent sterile speculum examinations for cervicovaginal sampling from the 41st week onwards. The fFN concentration in these samples was determined with a quantitative solid-phase enzyme-linked immunosorbent assay. Concentrations of <50 ng fFN per ml were characterised as negative test results, meaning that spontaneous delivery would not take place within 3 days, and those of > or =50 fFN ng/ml were taken as positive test results. Sensitivity and specificity of the fFN test were calculated for predicting spontaneous birth. Parametric and nonparametric tests were used for evaluating differences and correlations.

RESULTS

Spontaneous delivery took place after 2.5+/-2.5(SD) days with fFN values > or =50 ng/ml and after 4.7+/-3.6 days with fFN concentrations <50 ng/ml (P<0.001). Sensitivity and specificity of the fFN test predicting spontaneous onset of labour within 3 days, were 0.71 [95% confidence interval (CI) 0.58-0.86] and 0.64 (95% CI 0.48-0.78). If fFN > or =50 ng/ml then a spontaneous onset of labour is more likely to occur within 3 days (odds ratio 4.5 (95% CI 1.8-11.3).

CONCLUSIONS

The fFN test does not predict accurately enough whether or not birth will take place within 3 days of sampling. Nevertheless, the higher odds for spontaneous delivery within a few days when the test is positive may be of use in planning adjusted induction of labour.

The disappearance of fetal and donor red blood cells in alloimmunised pregnancies: a reappraisal

OBJECTIVE

To determine the proportional reduction per day in the number of fetal and donor red blood cells from the fetal circulation after intrauterine intravascular transfusions.

DESIGN

A retrospective study of 302 transfusions in 101 fetuses.

SETTING

The Department of Obstetrics and Gynaecology of the University Medical Centre Leiden, The Netherlands.

METHODS

We measured the haematocrit in fetal samples both before and after repeated intravascular intrauterine transfusion in fetuses with alloimmune disease. The percentage of fetal erythrocytes was determined in Kleihauer-Betke stained smears. The decline of fetal, donor and mixed red blood cells was calculated by dividing the proportional decrease of the haematocrit values of the number of days between transfusions, also after correction for changes in fetoplacental volumes. Results (given as mean [SD]) are derived from the proportional changes of haematocrit per day.

RESULTS

The interval between the first and second transfusion (15.5 days [SD 5.2]) was shorter than between subsequent transfusions (means ranging from 21.4 to 21.9 days; P < or = 0.0001). The decline per day of mixed, and of donor red blood cells, calculated without corrections for volume changes did not differ from those corrected for volume changes resulting from the transfusion and from fetal growth (correction factor 1.1 [SD 0.4]). Since the coefficient of variance is smaller for the uncorrected decline values, this type of calculation is preferable for clinical purposes. The disappearance of fetal erythrocytes after the first transfusion (6.1%/day [SD 2.9]) was faster than that of mixed fetal and donor red blood cells (3.2%/day [SD 1.2]; P < 0.0001) and of donor cells alone (1.4%/day [SD 1.6]; P < 0.0001). The decline of the mixed red blood cell population became the same as that of the donor cells (2.2%/day [SD 0.8]) after the second transfusion. This decline of donor cells was higher than after the first transfusion (1.4%/day [SD 1.6]; P < 0.05). After the first transfusion the fetal erythrocytes disappeared faster after transplacental puncture of the umbilical cord (6.6%/day [SD 2.8]) than after transamniotic punctures (5.4%/day [SD 2.7]; P = 0.05). The mixed red blood cell also decreased faster (3.5%/day [SD 1.3] versus 2.8%/day [SD 0.9]; P < 0.01).

CONCLUSION

The fast disappearance of fetal erythrocytes, especially after transplacental punctures, shows that the interval between the first and second transfusion needs to be shorter than that for intervals between subsequent transfusions. The number of donor erythrocytes declines by approximately 2% per day.

Mortality, severe respiratory distress syndrome, and chronic lung disease of the newborn are reduced more after prophylactic than after therapeutic administration of the surfactant Curosurf

OBJECTIVE

To test the hypothesis that prophylactic treatment with the surfactant Curosurf (Chiesi Farmaceutici SPA, Parma, Italy) improves survival and respiratory problems more than rescue treatment.

DESIGN

Meta-analysis of three prophylaxis versus rescue treatment trials, conducted in four countries.

METHODS

A meta-analysis was performed with the original, individual data of mortality, severe respiratory distress syndrome, and chronic lung disease of 671 newborns as outcomes. The random-effects logistic model (accounting for the trial-within-country structure) was applied and adjusted for imbalances in covariates.

RESULTS

The probability of each outcome differed between the countries, but the actual treatment effect itself did not. The adjusted odds ratios (ORs) and confidence intervals (CIs) for prophylaxis versus rescue were as follows: mortality: OR, .47; 95% CI, .30 to .73; severe RDS: OR, .50; 95% CI, .33 to .74; and chronic lung disease of the newborn in the survivors at day 28 after birth: OR, .54; 95% CI, .34 to .86. Gender, birth weight, gestational age, and prenatal administration of glucocorticosteroids were significant confounding covariates.

CONCLUSION

The analysis shows that for the porcine surfactant Curosurf, prophylactic administration of surfactant has significant advantages over rescue therapy.

Urine samples before dinner are preferable when studying changes in endogenous nitrate production under uncontrolled dietary conditions

Changes in nitric oxide production result in changes in nitrate excretion, but these are difficult to detect if the daily intake of nitrate varies substantially. Instead of using a sample of the combined urine produced in 24 h for analysis, we studied the urine nitrate concentration in urine discharge at various times of the day. This was done with urine samples from each of seven men after a high dietary nitrate intake, followed by a low dietary intake 24 h later. The lowest variability in nitrate concentration was found in the samples before dinner (late afternoon) (511 +/- 201 (S.D.) mumol/l). However, the pre-dinner samples after a day with a nitrate-rich meal had still a 40% increased nitrate concentration (623 +/- 147 mumol/l), when compared with samples before the high nitrate diet (440 +/- 90 mumol/l; P < 0.05). This effect disappeared on the second day after the high nitrate meal (476 +/- 108 mumol/l). Similar results were found when using the nitrate/creatinine ratio. We conclude that urine samples taken before nitrate rich meals are the most reliable samples for estimating (changes in) endogenous nitrate production.

Theoretical changes in neonatal hospitalisation costs after the introduction of porcine-derived lung surfactant ('Curosurf')

The aims of this study were to determine the effects of porcine-derived lung surfactant (PLS; 'Curosurf') therapy on mortality, periods of care and hospitalisation costs in a model cohort of 1000 premature neonates. In this cohort, 55% of the neonates would develop respiratory distress syndrome (RDS) and this would result in a mortality rate of 35%. The mortality rate among infants without RDS is 19%. Five modes of surfactant therapy were studied: (i) late rescue; (ii) early treatment; (iii) prophylaxis; (iv) multiple-dose treatment; and (v) high multiple-dose treatment. At a 55% incidence of RDS, we found that late rescue and single-dose treatment of severely ill neonates resulted in between 4 and 51 extra survivors, and that multiple-dose treatments increased the number of extra survivors by between 17 and 101. Early treatment and prophylaxis were found to be the most effective strategies, resulting in between 38 and 111 extra survivors. These 2 modes of surfactant therapy were also more effective than the other types of intervention at other incidences of RDS. The introduction of PLS therapy increased the total hospitalisation costs of the cohort of 1000 neonates [71 million Netherlands guilders (NLG) if no patients received surfactant] by 0.8 to 16.0% because of increased survival. Improved survival increased the mean period of intensive care by 0.5 to 12.6% and of nonintensive care by 0.6 to 16.0%, thereby increasing the need for more beds. Costs for PLS ranged from 0.3 to 1.2% of the total hospital costs. The additional costs of PLS therapy per additional survivor, compared with the 'do nothing' option, ranged from NLG68 034 to NLG136 233, and were lowest with prophylaxis and highest with high multiple-dose treatment. Savings in costs per survivor (0.2 to 4.1%) and nonsurvivor (5.1 to 23.1%) were highest with prophylaxis and early treatment, which were found to be the most cost effective of the strategies studied.

Biochemical lung maturity, static respiratory compliance, and pulmonary gas transfer in intubated preterm infants with and without respiratory distress syndrome

We investigated the relationship between tests of biochemical lung maturity [lecithin/sphingomyelin ratio (L/S ratio)], static compliance of the respiratory system (Crs), and estimates of pulmonary gas transfer [venous admixture and arterial/alveolar (a/A) ratio] in a group of intubated preterm infants with and without respiratory distress syndrome (RDS). Thirty infants were studied once (n = 26) or twice (n = 4). The L/S ratio was obtained by means of high-performance thin-layer chromatography and determination of the phosphorus content. Crs was obtained by the multiple occlusion technique. Transcutaneous blood gases and the percentage of oxygen in the inspired gas were recorded and estimates of pulmonary gas transfer were calculated using algorithms. L/S ratio and Crs correlated well (r = 0.73), indicating a higher compliance in biochemically more mature lungs. Both the a/A ratio and venous admixture correlated significantly with the L/S ratio and Crs (P < 0.001). Crs, L/S ratio, and a/A ratio decreased with increasing severity of radiological RDS, and the percentage venous admixture increased (P < 0.001). Sequential measurements in four infants during the acute phase and after RDS resolved indicated that clinical improvement coincided with improvements in biochemical lung maturity, Crs, and estimates of pulmonary gas transfer.

Changes of respiratory system mechanics in ventilated lungs of preterm infants with two different schedules of surfactant treatment

We investigated the time course of changes in the static respiratory system compliance and resistance in relationship to surfactant administration by means of single-breath and multiple-occlusion techniques. The study comprised 12 infants receiving a high-dose schedule (200 mg/kg, maximum 600 mg/kg) and 13 infants receiving a low-dose schedule (100 mg/kg, maximum 300 mg/kg) of porcine surfactant. Eight healthy preterm infants served as a comparison group. Respiratory mechanics were studied before and at 1.5, 8, and 72 h after surfactant administration. Results were related to changes in gas transfer, including an estimate of venous admixture. Static compliance improved after surfactant instillation, and changes were similar in the two treatment groups during the first eight h (0.8 In.(hour + 1) mL.kPa-1). The compliance values remained below the values of the healthy comparison group during the whole study period, but resistance remained at the same level. There was a considerable delay in changes of respiratory mechanics in relationship to the rapid fall of the venous admixture, from 27 to 19%, and the rapid increase of the transcutaneous oxygen pressure/fraction of inspired oxygen ratio from 13 to 27 kPa within the hour. There were no clues that short-term changes in compliance were masked by breathing at a higher and flatter portion of the pressure-volume curve. Both treatment schedules resulted in a similar improvement of compliance within 72 h and the two groups benefited similarly in terms of venous admixture.

Ultrastructural features of alveolar epithelial cells in the late fetal pulmonary acinus: a comparison between normal and hypoplastic lungs using a rat model of pulmonary hypoplasia and congenital diaphragmatic hernia

The aim of this study was to describe and compare the ultrastructural features and functional maturity of alveolar epithelial cells in hypoplastic and normal fetal rat lungs. Pulmonary hypoplasia in association with congenital diaphragmatic hernia was induced in fetuses by administration of 2,4-dichlorophenyl-p-nitrophenylether (Nitrofen) to pregnant Sprague Dawley rats (100 mg on day 10 of gestation). Lung tissue of Nitrofen-exposed and control fetal rats aged 19-22 days (vaginal plug day 1, birth day 23) was embedded in Epon. Semithin (1 micron) toluidine blue-stained sections were examined by light microscopy; ultrathin sections (approximately 80 nm) were studied via transmission electron microscopy. In bronchoalveolar lavage fluid from control and Nitrofen-exposed fetuses (day 22), phospholipid fractions and surfactant protein A content were measured semiquantitatively. On day 19 both control and Nitrofen-exposed lungs contained only cuboid alveolar epithelial cells; from day 20 there were cuboid, low cuboid, and thinner epithelial cells. The (low) cuboid cells contained large glycogen fields, some precursory stages of multilamellar bodies (MLBs), and just a few mature MLBs on day 19 and 20; smaller glycogen fields, more precursory stages, and more mature MLBs on day 21; and little or no glycogen but many precursory stages and mature MLBs on day 22. The thinner cells contained little or no glycogen and a few precursory stages of MLBs on days 20-22; very thin cells on day 22 contained neither glycogen nor any precursory stages of MLBs. MLBs and tubular myelin were seen in the lumens of future air spaces from day 20 onward. Nitrofen-exposed lungs differed from control lungs in that inclusion bodies (IBs) were less numerous in (low) cuboid alveolar cells on days 19 and 20, and more glycogen was seen on day 22. In addition intra- and extracellular "MLBs" in exposed lungs more often had an unusual appearance, i.e., a confluent structure and higher electron density. However, despite morphologic differences, there was no clear difference in phospholipid composition and SP-A content per mol phospholipid in bronchoalveolar lavage fluid. We conclude that morphologically hypoplastic lungs are less mature near term, without an apparent effect on surfactant composition.

Comparison of prophylaxis and rescue treatment with Curosurf in neonates less than 30 weeks' gestation: a randomized trial

OBJECTIVE

The aim of this randomized clinical trial was to evaluate the immediate effects of prophylactic administration of Curosurf and to compare outcomes after prophylactic or expectant management.

STUDY DESIGN

Porcine surfactant (Curosurf, 200 mg/kg body weight) was administered intratracheally within 10 minutes of birth to preterm neonates with a gestational age of 26 to 29 weeks (n = 75); rescue-eligible neonates (n = 72) were initially subjected to a sham maneuver. The primary end points of the trial, evaluated at the age of 6 hours, were to obtain (1) a 40% decrease in the ratio between transcutaneous oxygen tension (tcPO2) (kPa) and fraction of inspired oxygen (FIO2), and (2) a 50% decrease in the incidence of radiologically verified respiratory distress syndrome (RDS). After 6 to 24 hours, a similar dose of surfactant was given to the neonates of both the prophylaxis and the rescue-eligible group, if they needed mechanical ventilation with an FIO2 > or = 0.6.

RESULTS

At 6 hours the prophylaxis group had, in comparison with the rescue-eligible group, significantly higher tcPO2/FIO2 ratios (mean +/- SD: 39.7 +/- 15.3 vs 28.1 +/- 18.1; P < .001) and less severe RDS by radiological scoring (chi 2 = 14.9; P = .005). Severe RDS was present in 19% of the prophylactically treated neonates versus 32% in the rescue-eligible group (P < .05). The prophylaxis group needed shorter periods of FIO2 > 0.40 than the rescue-eligible neonates (P < .01), and eight neonates of the prophylaxis group (11%) versus 23 of the rescue-eligible group (32%) qualified for rescue treatment with surfactant in the interval 6 to 24 hours (P < .01). There were no differences in the incidence or severity of pneumothorax, pulmonary interstitial emphysema, cerebral hemorrhage, periventricular leukomalacia, patent ductus arteriosus, in the duration of mechanical ventilation or time in supplemental oxygen, or in mortality.

CONCLUSIONS

Subgroup analysis revealed (1) that administration of corticosteroids reduced the risk of developing neonatal RDS as effectively as did surfactant prophylaxis at birth, and (2) that prophylaxis was effective especially in neonates with gestational age < 28 weeks or birth weight < 1000 g, in male neonates, and in neonates who had received no antenatal treatment with corticosteroids. Our data indicate that prophylactic treatment with surfactant should be considered in high-risk neonates fulfilling these latter criteria.

[Prevention and treatment of respiratory distress syndrome in premature infants using intratracheally administered surfactants]

OBJECTIVE

To study the effects of administration of surfactant immediately after birth (prophylactic) or after 6 hr (therapeutic) to 81 Dutch preterm infants from a multicentre trial.

SETTING

University Hospital Leiden and Sint Joseph Hospital, Veldhoven.

DESIGN

A randomized controlled trial with stratification for biochemical lung (im)maturity. The aims of the study were (I): to improve the TcPO2/FiO2 ratio by 40% and (2) to prevent the respiratory distress syndrome by 50% at 6 hours after birth. The secondary goal was to compare effects of prophylactic versus therapeutic use of exogenous surfactant (from 6 hours onwards) in surfactant-deficient infants.

PATIENTS

The entrance criteria of the study were: (I) inborn children with a gestational age between 26 and 30 weeks, (2) elective intubation and (3) sampling of bronchotracheal or gastric aspirate. After randomization the children received surfactant within 10 minutes after birth prophylactically (n = 42) or 6 hours after birth if they needed more than 60% oxygen (13 of 39 control infants). A second dose of surfactant was given if, at 6 hours after the first dose, the FiO2 was still high (> or = 0.6).

TREATMENT

We used a natural porcine surfactant preparation (Curosurf) in a dose of 200 mg/kg given through the endotracheal tube.

RESULTS

The mean gestational age of the 81 infants was 28.2 weeks. The TcPO2/FiO2 ratios increased in the prophylactic group compared with the controls (38 versus 30 kPa; p < 0.05). RDS occurred less often and less severely in the prophylactic group (p < 0.05). Neonatal mortality was lower in the prophylactically treated infants (3/42) than in the control group (10/39; p < 0.05). Compared with the control infants with immature lungs, the immature prophylactically treated infants had six hours after birth higher TcPO2/FiO2 ratios (35 vs 13 kPa; p < 0.001), a 35% reduction of the incidence of RDS with a significant reduction of its severity (p < 0.05), and significantly lower mean airway pressures (0.87 versus 1.24 kPa; p < 0.005). The surfactant given 6 hours after birth to the immature controls resulted in an immediate improvement of the oxygenation. Nevertheless, these infants spent more time on the respirator and needed extra oxygen for longer periods than the immature infants prophylactically treated (p < 0.05).

CONCLUSION

Surfactant, given either prophylactically or therapeutically, results in clinical improvement of children with biochemically immature lungs. A prophylactic treatment, moreover, results in reduced incidence and severity of RDS, in a significant shortening of the time spent on the respirator and in reduced need of extra oxygen compared with therapeutic treatment. We recommend to give surfactant prophylactically or at the first signs of RDS.

Derivation of tumorigenic and non-tumorigenic mouse alveolar type-II cell lines from fetal type-II cells after a combined in vivo/in vitro carcinogen treatment

Alveolar type-II cells were isolated from the lungs of fetuses (day 18 of gestation) of the A/WySnAf (A/Sn) mouse strain, which were treated in utero at day 15 with the directly-acting carcinogen N-ethyl-N-nitrosourea (ENU). The isolated type-II cells were again treated with ENU during their initial growth in vitro. After a prolonged culture period, 5 cell lines were obtained, which were identified as type-II cell lines. Differences between cell lines were found with respect to contact-inhibited growth, cell doubling time and ability to grow in a serum-free medium. Two out of the 5 cell lines produced highly invasive type-II cell carcinomas after s.c. injection of 5 x 10(6) cells into nude mice. Thus, both tumorigenic and non-tumorigenic mouse alveolar type-II cell lines were derived after this combined in vivo and in vitro carcinogen treatment of fetal mouse alveolar type-II cells. This offers the possibility of studying in vitro the factors thought to influence lung tumorigenesis in vivo. In addition, our findings strongly suggest that alveolar type-II cells are the progenitor cells of malignant mouse lung tumors.

Cerebral and aortic blood flow velocity patterns in preterm infants receiving prophylactic surfactant treatment

Blood velocity in the internal carotid artery (ICA) and in the descending thoracic aorta (DAo) was investigated used Duplex-Doppler ultrasound in 14 infants of less than 30 weeks gestation, treated prophylactically with surfactant, and in 11 comparable infants with relatively mature lungs who served as controls. After surfactant administration, blood gases, pH or FiO2 were not different between the groups. Temporal mean blood velocity in the ICA was used as a relative measure of cerebral flow (TMFV-cer), and its coefficient of variation (CV-cer) was used to assess fluctuations in cerebral blood velocity. The pulsatility index (PI) in the ICA (PI-cer) and DAo (PI-DAo) was used to estimate if a left-to-right shunt was present. During surfactant instillation TMFV-cer was abnormally low and CV-cer indicated a fluctuating cerebral blood velocity. At 10 min after surfactant administration, TMFV-cer of the treated infants was higher compared to the controls, while CV-cer was stable in both groups. PI-cer and PI-DAo were abnormally high during the first hour of life after surfactant treatment, suggesting a left-to-right shunt without, however, clinical signs of a hemodynamically important ductus arteriosus. We suggest that cerebral perfusion is affected during and at 10 min after surfactant instillation. Left-to-right shunting appears to be a common event following surfactant treatment.

Comparison of the pulmonary surfactant content in alveolar macrophages of newborn, young, and adult rats

The phospholipid composition of the 150-g pellet containing macrophages from neonatal lung lavages resembles that of surfactant. To study whether this composition reflects the surfactant content of the macrophage, we isolated the alveolar phospholipids and macrophages from the lavage fluids of fetal, newborn, young, and adult Wistar rats. The alveolar surfactant phospholipids increased from fetal levels of 2.8 nmol/mg dry lung weight (DLW) to 39 nmol/mg DLW at day 1, decreased sharply within the first week, and stabilized at a level of 2-4 nmol/mg DLW after day 15. The number of alveolar macrophages increased significantly during the first postnatal day from approximately 750 to more than 5000 (per mg DLW), decreased during the next 4 days, and varied strongly at older ages. We estimated the surfactant content in the macrophages semiquantitatively by polarization microscopy. Birefringence augmented significantly during the first 1.5 days after birth and decreased after that concurrently with the amount of alveolar surfactant. However, only cells without birefringent inclusions sedimented at 150g, whereas the phospholipid composition of the pellets falsely suggested that large amounts of intracellular surfactant were present in its cells. At least two populations of macrophages (surfactant-rich and surfactant-poor) are present in the growing animal. We suggest that differences in function of these various types of macrophages also might depend on surfactant congestion.

Estimated costs of different treatments of the respiratory distress syndrome in a large cohort of preterm infants of less than 30 weeks of gestation

Within a model cohort of 1,000 preterm infants of less than 30 weeks of gestation, the incidence and mortality of RDS change if corticosteroids are used prenatally and surfactant prophylactically or therapeutically after birth. Combined pre- and postnatal therapies give the best results: approximately 125 extra survivors. Therapeutic surfactant administration even in combination with prenatal corticosteroids has cost implications because extra intensive care beds (7-11%) are needed. More special care places (12-24%) are required after each type of intervention. The estimated costs per extra survivor are the lowest for prenatal corticosteroid administration. The combination of corticosteroids prenatally and prophylactic surfactant postnatally seems to be most cost-effective because it produces the greatest number of survivors and the lowest number of intensive and high dependency care days in hospital.

Development of a human lung surfactant, derived from extracted amniotic fluid

Using a surfactant preparation of human origin for the treatment of the respiratory distress syndrome (RDS) instead of an animal-derived surfactant will minimize immunological problems. Therefore we isolated surfactant material from human amniotic fluid. Protein and phospholipid fractions of extracted human amniotic fluid (HAFS) were separated by Lipidex 5000 or acidulated LH20 liquid chromatography systems. Fractions of HAFS, the phospholipid or the recombined phospholipid-protein fractions, were tested in the 27-day fetal rabbit model. The results were compared with the results of the corresponding fractions of extracted ovine lung lavage (EOS) and of the already clinically tested surfactant Curosurf. The in situ surface activity of HAFS, EOS, and of their combined phospholipid + protein fractions (200 mg/kg body wt.) resulted in a lung compliance which was significantly higher than the control (saline) values. The compliances of HAFS, EOS, their combined fractions, and Curosurf were similar, but the lung stability values (V5) differed significantly among these surfactant extracts. The best V5 values (greater than or equal to 0.020 ml/g body wt.) were found after installing EOS or its LH20 phospholipid + protein fractions. HAFS had a poor stabilizing capacity which increased significantly after Lipidex chromatography and even more after enrichment of the Lipidex material with 10% palmitic acid. The Lipidex HAFS + 10% palmitic acid surfactant is at present the best obtainable human surfactant extract. Further development is in progress for the clinical application of this surfactant in preterm neonates.

Fetal mouse alveolar type II cells in culture express several type II cell characteristics found in vivo, together with major histocompatibility antigens

Alveolar type II cells were isolated from fetal mouse lung by differential adherence and obtained in monolayer culture. Cultures display a high degree of purity as shown by histochemical and immunocytochemical staining procedures. Seventy-five percent of cells stained positive with specific anti-lavage serum mouse (SALS-M), an antiserum specific for (pre)alveolar type II cells of the mouse, and osmiophilic bodies were present in 82% of cells. These and other characteristics of type II cells in culture correspond to those of alveolar type II cells in fetal mouse lung. The pattern of reactivity of these cells with various anti-cytokeratin antibodies is described, and we show that, in contrast to rat type II cells, they do not exhibit alkaline phosphatase activity. Identity of the type II cell cultures was shown by their specific phospholipid composition and surfactant protein A (SP-A) content. The fetal alveolar type II cells in culture were found to synthesize and express class I but not class II major histocompatibility complex (MHC) antigens. The possibility to culture fetal alveolar type II cells of the mouse and the availability of genetically well-defined inbred and transgenic mouse strains opens ways to study the genetics of type II cell differentiation and function. Also, the in vitro availability of alveolar type II cells, the progenitor cells of mouse lung tumors, will enable us to study in vitro several of the processes involved in lung tumorigenesis in the mouse.