In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.

Context: Impaired neurodevelopmental outcome represents a major morbidity for survivors of infant heart surgery for congenital heart defects. Previous studies in these neonates have reported preoperative microcephaly, periventricular leukomalacia, and other findings. The hypothesis of this study is that preoperative cerebral blood flow is substantially diminished and might relate to preoperative neurologic conditions.', 'Preoperative brain magnetic resonance imaging was performed. Cerebral blood flow measurements in infants with congenital heart defects were obtained by using a novel noninvasive magnetic resonance imaging technique, pulsed arterial spin-label perfusion magnetic resonance imaging. Cerebral blood flow was measured before the operation under standard ventilation and repeated after increased carbon dioxide.', 'A total of 25 term infants were studied. The average age at the time of the operation was 4.4 +/- 4.6 days. Congenital heart defects varied widely. Microcephaly occurred in 24% (6/25). Baseline cerebral blood flow was 19.7 +/- 9.2 mL . 100 g -1 . min -1 (8.0-42.2 mL . 100 g -1 . min -1 ). Five patients had cerebral blood flow measurements of less than 10 mL . 100 g -1 . min -1 . Mean hypercarbic cerebral blood flow increased to 40.1 +/- 20.3 mL . 100 g -1 . min -1 (11.4-94.0 mL . 100 g -1 . min -1 , P < .001). Pairwise analyses found that low hemoglobin levels were associated with higher baseline cerebral blood flow values ( P = .04). Periventricular leukomalacia occurred in 28% (7/25) and was associated with decreased baseline cerebral blood flow values ( P = .05) and a smaller change in cerebral blood flow with hypercarbia ( P = .003).\Question: Is preoperative cerebral blood flow diminished in neonates with severe congenital heart defects?
Structural brain abnormalities are common in these neonates before surgical intervention. Preoperative cerebral blood flow for this cohort was low and drastically reduced in some patients. Low cerebral blood flow values were associated with periventricular leukomalacia. Carbon dioxide reactivity was preserved but might be compromised by some aspects of the cardiac anatomy. The full spectrum of cerebral blood flow measurements with this technique in congenital heart defects and their long-term significance require continued investigation.

Context: The goal of this study was to identify genetic determinants of plasma N-terminal proatrial natriuretic peptide (NT-proANP) in the general community by performing a large-scale genetic association study and to assess its functional significance in in vitro cell studies and on disease susceptibility.', 'Genotyping was performed across 16 000 genes in 893 randomly selected individuals, with replication in 891 subjects from the community. Plasma NT-proANP1-98 concentrations were determined using a radioimmunoassay. Thirty-three genome-wide significant single-nucleotide polymorphisms were identified in the MTHFR-CLCN6-NPPA-NPPB locus and were all replicated. To assess the significance, in vitro functional genomic studies and clinical outcomes for carriers of a single-nucleotide polymorphism rs5063 (V32M) located in NPPA that represented the most significant variation in this genetic locus were assessed. The rs5063 variant allozyme in transfected HEK293 cells was decreased to 55±8% of wild-type protein (P=0.01) as assessed by quantitative western blots. Carriers of rs5063 had lower NT-proANP levels (1427 versus 2291 pmol/L; P<0.001) and higher diastolic blood pressures (75 versus 73 mm Hg; P=0.009) and were at an increased risk of stroke when compared with wild-type subjects independent of age, sex, diabetes mellitus, hypertension, atrial fibrillation, and cholesterol levels (hazard ratio, 1.6; P=0.004).\Question: Does circulating atrial natriuretic peptide genetic association study identify a novel gene cluster associated with stroke in whites?
This is the first large-scale genetic association study of circulating NT-proANP levels performed with replication and functional assessment that identified genetic variants in the MTHFR-CLCN6-NPPA-NPPB cluster to be significantly associated with NT-proANP levels. The clinical significance of this variation is related to lower NT-proANP levels, higher blood pressures, and an increased risk of stroke in the general community.

Context: At birth the fetus emerges from a sterile environment into a nonsterile one. This process is associated with activation of the fetal immune system which protects the fetus against infection in the newborn period. We conducted this study to determine whether activation of the monocyte-neutrophil system occurs in fetuses before premature birth.', 'Forty patients in premature labor with intact membranes underwent cordocentesis for research purposes. Fetal blood was analyzed with the use of flow cytometry to measure the cell surface markers CD11c, CD13, CD15, and CD67, which are associated with monocyte and neutrophil activation, and CD14 and CD63, which were used as controls.', 'Twenty-eight percent (11/40) of the infants were delivered prematurely within 72 hours of entering the study while the remainder were delivered at term. Our data clearly indicate that premature infants delivered within 72 hours had a higher percentage of CD11c, CD13, CD15, and CD67 than those delivered at term. In contrast, there were no significant differences in the percentages of CD14 and CD63.\Question: Is premature parturition characterized by in utero activation of the fetal immune system?

Activation of the monocyte-neutrophil system exists in fetuses destined for premature delivery. These findings indicate that premature parturition is associated with in utero immune system activation.