Increased risk of intracranial hemorrhage in preterm infants with OPRM1 gene A118G polymorphism.

BACKGROUND: To investigate the relationship between the OPRM1 gene A118G polymorphism and intracranial hemorrhage (ICH) in premature infants and identify the relevant genes in disease occurrence. METHODS: In the present case study analysis, polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to detect the genotype and allele frequencies of the OPRM1 gene All8G single nucleotide polymorphism (SNP) in a case group of premature infants with ICH (n=167) and a control group of premature infants (n=163) without ICH. RESULTS: In the case group, 73 (43.7%) wild type A118 homozygous (A/A), 82 (49.1%) mutant heterozygous (A/G), and 12 (7.2%) mutant G118 homozygous (G/G) individuals were observed. The frequencies of A and G alleles were 68.3% and 31.7% respectively. In the control group, 89 (54.6%) wild type A118 homozygous (A/A), 68 (41.7%) mutant heterozygous (A/G), and 6 (3.7%) mutant G118 homozygous (G/G) individuals were observed. The frequencies of A and G alleles were 75.5% and 24.5% respectively. There was no significant difference in the frequency distribution of the OPRM1 gene A118G polymorphism between the two groups (χ2=4.839, P=0.089). There was a significant difference in the positive rate of wild-type AA and mutant-type (A/G + G/G) between the two groups (χ2=3.913, P=0.048). Carrying the G allele of the individual was 1.5 times more frequent suffering from the risk of ICH than carrying the A allele [odds ratio (OR): 1.549; 95% confidence interval (CI): 1.003-2.391], indicating that the OPRM1 118G allele was positively correlated with ICH and can increase the risk of ICH occurrence. CONCLUSIONS: The OPRM1 gene A118G polymorphism is associated with ICH in premature infants. The OPRM1 gene A118G may play a critical role in the occurrence of ICH.

Application of NT-proBNP in ventilator weaning for preterm infants with RDS.

OBJECTIVE: To evaluate the value of N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels along with spontaneous breathing trial (SBT) in the prediction of ventilator weaning outcome among respiratory distress syndrome (RDS) preterm infants ready to wean. METHODS: NT-proBNP along with plasma albumin concentration, serum sodium, serum potassium, and hematocrit were measured immediately before SBT in preterm infants (≤32 weeks) mechanically ventilated due to RDS. Extubation was considered successful if infants remained extubated >48 hr. Either SBT failure or extubation failure was considered weaning failure. RESULTS: Sixty-three of 88 infants passed the SBT and were subsequently extubated. Of these, two (3.2%) cases rapidly developed laryngeal dyspnea imposing reintubation (excluded from analysis). Of the remaining 61 infants, 45 (73.8%) cases had successful extubation, and 16 (26.2%) cases were reintubated. Infants who failed weaning had lower gestational age, birth weight, and plasma albumin concentrations, higher NT-proBNP, doses of surfactant, occurrence of ventilator-associated pneumonia, and occurrence of pulmonary arterial hypertension than those who did not. NT-proBNP was the only independent factor that could predict weaning failure (OR = 1.872; P = 0.044). The ROC-AUC for NT-proBNP to predict weaning failure was 0.977 (95% CI 0.918-0.997; P < 0.001). The cut-off of NT-proBNP level 18,500 pg/ml to predict weaning failure had a positive likelihood ratio of 25.180. The addition of NT-proBNP to SBT in prediction of weaning failure significantly improved the net reclassification improvement (NRI = 0.224; P = 0.034). CONCLUSION: NT-proBNP is an independent factor that could predict weaning failure. Measurement of NT-proBNP prior to SBT may be helpful in promoting successful ventilator weaning along with SBT.

[Investigation on factors related to pyelic separation in early newborns].

OBJECTIVE: To explore the relationship of pyelic separation with gestational age, body weight and sex in early newborns. METHODS: A total of 320 neonates were examined by renal ultrasound 2-7 days after birth. The neonates included 180 boys and 140 girls, with a mean gestational age of 36±3 weeks (28-42 weeks) and a mean birth weight of 2430±1000 g (900-4870 g). Correlation analysis was performed between renal pelvis anteroposterior diameter (APD) and gestational age/body weight. The newborns were grouped based on gestational age, body weight and sex and the incidence of pyelic separation was compared among the groups. RESULTS: Pyelic separation was found in 100 of the 320 newborns. The incidence of pyelic separation in boys (37.8%, 70 cases) was significantly higher than in girls (22.2%, 30 cases) (P<0.05). The incidence rates of pyelic separation on the left side, right side and both sides were 59%, 13% and 29% respectively in boys, and 53%, 7% and 40% respectively in girls. There was no significant difference in the location of renal pelvis separation between boys and girls (P>0.05). There significant difference in the incidence of pyelic separation between different gestational age groups (P>0.05). APD was positively correlated with gestational age and birth weight (P<0.05). The incidence of pyelic separation was negatively correlated with birth weight in all newborns except those who were macrosomic (P<0.05). CONCLUSIONS: The incidence of pyelic separation in early newborns is closely associated with birth weight and sex. APD is positively correlated to gestational age and birth weight. Pyelic separation often occurs more frequently on the left side or both sides than on the right side.

[Association between platelet-activating factor acetylhydrolase gene polymorphism and intracranial hemorrhage in preterm infants].

OBJECTIVE: To explore whether Val279Phe single nucleotide polymorphisms (SNPs) in the 9th exon of platelet-activating factor acetylhydrolase (PAF-AH) are associated with intracranial hemorrhage in preterm infants. METHODS: A case-control study was performed. Polymerase chain reaction (PCR) was used to test genotype and allele frequencies of the 9th exon Val279Phe SNPs of PAF-AH in 58 preterm infants with intracranial hemorrhage (hemorrhage group) and 65 preterm infants without intracranial hemorrhage (control group). RESULTS: There were significant differences in genotype frequency of Val279Phe SNPs in the 9th exon of PAF-AH between the hemorrhage and control groups (P<0.05). Frequency of normal genotype in the hemorrhage group (63.8%) was significantly lower than in the control group (81.5%). In contrast, frequency of heterozygous genotype (34.5%) in the hemorrhage group was significantly higher than in control group (16.9%). There were also significant differences in allele frequency of Val279Phe SNPs in the 9th exon of PAF-AH between the two groups (P<0.05). T allele frequency in the hemorrhage group (19.0%) was significantly higher than in the control group (10.0%). CONCLUSIONS: Val279Phe SNPs in the 9th exon of PAF-AH may be associated with intracranial hemorrhage in preterm infants.