Plasma levels of asymmetric dimethylarginine in premature neonates: its possible involvement in developmental programming of chronic diseases

Aim: The endothel dysfunction in early life may play a role in developmental programming of cardiovascular morbidity. The changes of dimethylarginines' plasma levels during the first month among preterm infants and their determinants had been investigated in our study.
Methods: Twenty preterm infants of healthy mothers were studied. Mean (±SD) birth weight and gestational age were 919.5 ± 235.5 g and 26.7 ± 1.6 weeks, respectively. Blood samples were taken by venipuncture at the 3rd, 7th, 14th, 21st and 28th days. Plasma concentrations of L-arginine, asymmetric and symmetric dimethylarginine (SDMA) were measured by liquid chromatography-mass spectrometry method, evaluated by multivariate linear regression analysis.
Results: L-arginine (p < 0.001) and asymmetric dimethylarginine (ADMA) levels (p < 0.001) were positively associated with postnatal age. ADMA levels were negatively correlated with gestational age (p = 0.007), dopamine-need on the 3rd day of life (p = 0.015) and late infection (p = 0.038). The higher birth weight was associated with higher L-arginine (p = 0.052) and ADMA (p = 0.002) concentrations. The dopamine-need on the 7th day of life had a significant effect on postnatal elevation of SDMA levels (p = 0.035).
Conclusion: The progressive increase of ADMA levels described by our study among preterm infants suggests that early endothel dysfunction may take part in developmental programming of chronic adult diseases.     

Birth by cesarean section is associated with elevated neonatal plasma levels of dimethylarginines

Background: This study was undertaken to compare the effects of vaginal delivery and cesarean section on the l‐arginine‐nitric oxide system by measuring levels of l‐arginine, an endogenous nitric oxide synthase antagonist asymmetric dimethylarginine (ADMA), and symmetric dimethylarginine (SDMA) in the cord blood and postnatally. Methods: Plasma samples were obtained from the umbilical vein and artery at birth and from peripheral venous blood on the second postnatal day in 30 full‐term newborn infants: 10 born vaginally and 20 born by cesarean section. Results: After vaginal delivery, ADMA concentration was higher in the umbilical vein than in the umbilical artery (mean 1.06 vs 0.90 µmol/L [P= 0.027]); and ADMA level fell after birth to 0.66 µmol/L on the second postnatal day (P= 0.007 vs umbilical artery). Newborns born by cesarean section had similar ADMA levels in umbilical arterial and venous blood, 1.19 and 1.18 µmol/L, and the ADMA level fell to 0.84 µmol/L by the second postnatal day (P < 0.001). Vaginal birth induced neither significant umbilical venoarterial difference nor a postnatal fall in SDMA. After cesarean section, SDMA was essentially the same in umbilical vein, umbilical artery and postnatal peripheral vein samples. At 2 days of age, both ADMA and SDMA levels stayed higher in infants born by cesarean section than in vaginally born infants. Conclusions: ADMA level falls after both vaginal and cesarean birth, whereas SDMA level does not. The higher ADMA level after cesarean birth compared with vaginal birth may contribute to decreased nitric oxide production and bioavailability in neonatal vascular beds.     

不对称二甲基精氨酸与新生儿持续性肺动脉高压病理进程的相关性研究

目的 探讨不对称二甲基精氨酸(asymmetric dimethylarginine,ADMA)在新生儿持续性肺动脉高压(persistent pulmonary hypertension of the newborn,PPHN)足月儿循环系统中的变化规律及其与治疗响应的关系,探索其成为治疗靶标和治疗响应标志物的可能性...     

Advanced intrauterine growth restriction is associated with reduced excretion of asymmetric dimethylarginine

Background

High blood levels of asymmetric dimethylarginine (ADMA) are associated with future development of adverse cardiovascular events. The ADMA/symmetric dimethylarginine (SDMA) ratio is a marker of ADMA catabolism, with a high ADMA/SDMA ratio being suggestive of reduced ADMA excretion.

Aims

This study aimed a) to verify the presence of a statistically significant difference between ADMA/SDMA ratio levels in a group of young adult subjects who were born preterm with an extremely low birth weight (ex-ELBW) and a group of healthy adults born at term and b) to seek correlations between ADMA/SDMA ratio levels in ex-ELBW and anthropometric and clinical parameters (gender, chronological age, gestational age, birth weight, and length of stay in the Neonatal Intensive Care Unit).

Subjects, study design, outcome measures

Thirty-seven ex-ELBW subjects (11 males [M] and 26 females [F], aged 17–28 years, mean age: 22.2 ± 1.8 years) were compared with 37 controls (11 M and 26 F). ADMA/SDMA ratio levels were assessed for each patient included in the study.

Results

ADMA/SDMA ratio in ex-ELBW subjects was higher compared to controls (1.42 ± 0.31 vs 0.95 ± 0.14, p < 0.002) and inversely correlated with birth weight (r = − 0.68, p < 0.0001) and gestational age (r = − 0.54, p < 0.0005).

Conclusions

ADMA catabolism is significantly decreased in ex-ELBW subjects compared to controls, underlining a probable correlation with restriction of intrauterine growth. These results suggest the onset of early circulatory dysfunction predictive of increased cardiovascular risk in ex-ELBW.     

Carbamoyl phosphate synthetase polymorphisms as a risk factor for necrotizing enterocolitis

A C-to-A nucleotide transversion (T1405N) in the gene that encodes carbamoyl-phosphate synthetase 1 (CPS1) has been correlated with low plasma concentrations of L-arginine in neonates. As plasma L-arginine concentrations are decreased in premature infants with necrotizing enterocolitis (NEC), we hypothesized that the CPS1 T1405N polymorphism would correlate with the presence of NEC. We analyzed the CPS1 genotypes for the T1405N polymorphism in 17 preterm infants (相似文献   

Host defence lectins in preterm neonates

AIM: Deficiency in collectins is discussed as a risk factor for pulmonary and systemic infections in children and adults. The objective of this study was to determine serum concentrations of surfactant protein D (SP-D) and mannose-binding lectin (MBL) in preterm and term infants at birth. METHODS: 47 preterm infants below 32 wk gestational age (GA) and 19 healthy, term newborn infants at birth have been included in the study, and SP-D as well as MBL concentrations have been determined in umbilical cord blood samples using sandwich ELISA technique. In addition, SP-D concentrations were assessed in tracheal aspirates (TA) of 24 mechanically ventilated preterms and in infants without pulmonary complications before elective surgery. RESULTS: MBL serum concentrations were significantly lower in preterms <32 wk GA (756.7 ng/ml; 14.6-11 184 ng/ml) compared to term newborns (3168.9 ng/ml; 282.3-7679.5 ng/ml; p=0.005; median and range, respectively). Serum SP-D concentrations were significantly decreased in preterms between 28 and 32 wk GA (1.4 ng/ml; 0-4.6 ng/ml; n=26) compared to term infants (2.2 ng/ml; 1.2-3.3 ng/ml; p=0.05) and were found to positively correlate with history of antenatal corticosteroids and chorioamnionitis. SP-D concentrations in TA were increased in preterm infants between 28 and 32 wk GA with respiratory distress syndrome (RDS) (25.0 ng/ml; 0.9-44.7 ng/ml; n=12) compared to control subjects (6.6 ng/ml; 0.5-30.4 ng/ml; n=12) in contrast to extremely immature infants <28 wk GA suffering from RDS (4.4 ng/ml; 0.8-78.4 ng/ml; n=12). CONCLUSION: In preterm infants, significant changes occur in collectin umbilical cord blood concentrations and pulmonary SP-D levels. Functional aspects of these findings need to be addressed further.     

Influence of gestational age and intrauterine growth on leptin concentrations in venous cord blood of human newborns

BACKGROUND: The ob gene product leptin is involved in the regulation of body weight and energy expenditure, suggesting a potential role of leptin in embryonal and fetal development and progression of pregnancy. In term infants, leptin concentrations showed a positive correlation with birth weight. We aimed at comparing leptin cord blood levels in AGA (appropriate for gestational age) to SGA (small for gestational age) preterm and term newborns. PATIENTS AND METHODS: Ninety-seven human newborns, 47 females and 50 males, 33 born at term and 64 born before 36 weeks of gestation, were studied prospectively. Leptin concentrations in venous cord blood were determined using a specific RIA (radioimmunoassay). RESULTS: In term newborns, mean gestational age (GA) was 39 weeks (wk) (+/- 0.7 wk) and mean birth weight (BW) was 3316 g (+/- 473 g); in preterm newborns (n = 64), mean GA was 30 wk (+/- 5.0 wk) and mean BW was 1398 g (+/- 505 g). Mean standard deviation score of birth weight (BW SDS) was calculated as - 0.47. Mean leptin concentrations in term newborns differed significantly from those in preterm newborns (9.21 +/- 2.63 ng/ml vs. 1.58 +/- 0.88 ng/ml; p < 0.0001). In preterm and term infants, leptin concentrations showed a linear correlation with BW (r = 0.46; p < 0.0001) and GA (r = 0.48; p < 0.0001), respectively. Leptin levels were best predicted by an exponential regression model with GA (Leptin = exp(- 4.41 + 0.14 x GA); r = 0.61; p < 0.0001). Using multivariate regression analysis (r = 0.57; p < 0.0001), we found significant influences of GA (p < 0.00001) and BW SDS (p < 0.05) on leptin levels. No difference was observed between leptin values in AGA versus SGA preterm infants. CONCLUSION: These data suggest fetal leptin levels to be primarily determined by GA and additionally modulated by growth restriction in term newborns. We found a dramatic increase at weeks 33 to 35 of gestation and no modulation by BW SDS in very preterm infants.     

妊娠期合并糖代谢异常对新生儿胰岛素敏感性的影响

目的探讨妊娠期合并糖代谢异常对子代新生儿期胰岛素敏感性的影响。方法选择2009年12月至2010年11月本院产科出生的新生儿,根据母亲妊娠期是否合并糖代谢异常分为糖代谢异常母亲的新生儿和糖代谢正常母亲的新生儿。所有研究对象均进行出生体格测量,并于生后 3 天内测定空腹血糖( FPG) 和空腹血清胰岛素( FINS) ,计算胰岛素敏感指数( ISI) ,采用胰岛素稳态模型( HOMA) 计算胰岛素抵抗指数( IR) ,即 HOMA-IR,其中 FINS、ISI 和 HOMA-IR 值为胰岛素敏感性的评价指标。以性别、胎龄、出生体重为协变量,分别在早产儿和足月儿中进行胰岛素敏感性的协方差分析。结果 89 例早产新生儿和 96 例足月新生儿纳入分析。糖代谢异常母亲新生儿的出生体重、出生身长和重量指数( PI) 与糖代谢正常母亲的新生儿相比,差异无统计学意义( P >0. 05) 。与糖代谢正常母亲的早产儿相比,糖代谢异常母亲的早产儿 FPG 降低、FINS 升高,差异有统计学意义[FPG( mmol/L) : ( 4. 00 ±0. 25) 比( 4. 82 ±0. 18) ,FINS( 经对数 Lg 转换) : ( 0. 69± 0. 06) 比( 0. 54 ± 0. 04) ,P < 0. 05],ISI 值降低、HOMA-IR 值升高,但差异无统计学意义[ISI( 经对数 Ln 转换) : ( -2. 89 ±0. 15) 比( -2. 78 ±0. 11) ,HOMA-IR 值( 经对数 Lg 转换) : ( -0. 10 ±0. 06)比( -0. 15 ±0. 05) ,P >0. 05]; 足月儿中糖代谢异常母亲的新生儿 FPG、FINS 和 HOMA-IR 值低,ISI 值高,但差异均无统计学意义[FPG( mmol / L) : ( 4. 68 ± 0. 23) 比( 5. 17 ± 0. 13) ,FINS( 经对数 Lg转换) : ( 0. 56 ±0. 06) 比( 0. 61 ±0. 03) ,HOMA-IR 值( 经对数 Lg 转换) : ( -0. 14 ±0. 06) 比( -0. 03± 0. 03) ,ISI( 经对数 Ln 转换) : ( - 2. 79 ± 0. 14) 比( - 3. 04 ± 0. 08) ,P > 0. 05]。结论母亲妊娠期合并糖代谢异常虽然对新生儿的出生体重没有影响,但血糖仍然呈现低水平趋势,且对早产儿胰岛素敏感性可能有一定的影响。     

Circulating levels of biologically active and immunoreactive intact parathyroid hormone in human newborns

We evaluated circulating levels of biologically active and immunoreactive intact parathyroid hormone [iPTH-(1-84)] in 47 newborns at birth and eight hypocalcemic preterm infants during the first 10 d of life. Use of two sensitive detection systems, the cytochemical bioassay and an immunoradiometric assay specific for intact parathyroid hormone, enabled us to compare plasma concentrations of PTH-like bioactivity (bioPTH) and iPTH-(1-84). Mean umbilical venous plasma bioPTH was elevated in nondiabetic term and preterm newborns [22.5 +/- 3.1 (+/- SEM) and 15.8 +/- 2.5 ng-equiv/L, respectively] compared with normal adult subjects (9.8 +/- 2.6 ng-equiv/L; p less than 0.01). Umbilical bioPTH was suppressed in five term infants of diabetic mothers (2.6 +/- 0.4 ng-equiv/L). In contrast, iPTH-(1-84) was low in term and preterm nondiabetic infants' and term infants of diabetic mothers' umbilical samples (5.4 +/- 1.5, 4.3 +/- 1.5, and 2.4 +/- 1.0 ng/L, respectively). Umbilical venous bioPTH was highly correlated with the magnitude of the transplacental calcium gradient (r = 0.90; p less than 0.05). In eight preterm infants studied longitudinally, by 24-36 h of life, declining plasma total and ionized calcium (1.71 +/- 0.04 and 0.78 +/- 0.03 mmol/L, respectively) were accompanied by a significant rise in both bioPTH (41.2 +/- 6.3 ng-equiv/L) and iPTH-(1-84) (56.3 +/- 11.6 ng/L). These data indicate that the 3rd trimester fetoplacental circulation contains levels of bioPTH several-fold higher than those of immunoreactive intact hormone. We also conclude that even hypocalcemic preterm newborn infants can significantly elevate circulating levels of PTH.     

Increased epidermal growth factor levels in human milk of mothers with extremely premature infants

Maternal milk is the major source of nutrients and growth-promoting substances in the first weeks of life for the majority of neonates. Epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha) are trophic peptides present in human milk with significant healing effects on injured gastrointestinal mucosa. Decreasing gestational age of neonates is associated with higher risk of developing gastrointestinal disorders, and human milk provides better protection against these diseases compared with formula. The aim of this study was to evaluate the concentrations of EGF and TGF-alpha in human milk collected from mothers with infants born: extremely preterm, preterm, and full term. Milk samples were collected at the end of first, second, and fourth week postpartum from each mother of infants born in one of the three gestational age groups: extremely preterm (23-27 wk, n = 16), preterm (32-36 wk, n = 16), and full term (38-42 wk, n = 15). Milk concentrations of EGF and TGF-alpha were quantified with a homologous RIA in the milk aqueous fraction. Concentrations of EGF in human milk from the extremely preterm group (23-27 wk) were significantly higher compared with values from the preterm and full-term groups throughout the first month of lactation. A similar pattern was observed with human milk TGF-alpha; however, milk TGF-alpha levels were lower than EGF. In conclusion, we have found higher concentrations of EGF and TGF-alpha in human milk of mothers with extremely preterm babies. These data may indicate the potential importance of milk-borne EGF and TGF-alpha for the development of extremely premature infants.     

Inflammatory mediators in umbilical plasma from neonates who develop early-onset sepsis

OBJECTIVES: To study whether early-onset neonatal sepsis is associated with a prenatal immune response with elevated umbilical plasma levels of inflammatory mediators, and to study whether mediator levels may be helpful in identifying infected neonates. SETTING: Nested case-control study. METHODS: Cord blood was sampled from 7,073 consecutively delivered neonates. After review of the medical records, neonates suspected to suffer from infection were classified as infected (n = 52) or noninfected but sick controls (n = 33). We also included a group of healthy controls (n = 99). Umbilical plasma levels of tumour necrosis factor-alpha (TNFalpha), interleukin (IL)-1beta, IL-6, IL-8, soluble TNF receptors (p55 and p75), IL-1 receptor antagonist (IL-1RA) and C-reactive protein were measured by immunoassays. RESULTS: Infected neonates had higher levels of TNFalpha, IL-1beta, IL-6, IL-8, p55, p75 and IL-1RA than healthy controls (all p < 0.01). Among preterm infants (GA <37 weeks), those with infection (n = 11) had higher levels of IL-1beta, IL-6, IL-8, p55 and p75 than noninfected sick controls (n = 13) (all p < 0.05), but among term infants, the infected did not differ from the noninfected sick controls. Receiver operator characteristic plots showed that IL-1beta, IL-6 and IL-8 identified preterm infected neonates accurately. CONCLUSIONS: Early-onset neonatal sepsis is associated with a prenatal immune response with increased TNFalpha, IL-1beta, IL-6, IL-8, p55, p75 and IL-1RA levels in umbilical plasma. Among neonates who present symptoms suggestive of infection, cytokine levels may be helpful in identifying preterm, but not term infected individuals.     

Extracellular release of bactericidal/permeability-increasing protein in newborn infants

Upon activation, polymorphonuclear leucocytes (PMN) release bactericidal/permeability-increasing protein, (BPI) from their azurophil granules. BPI selectively binds to the lipopolysaccharide (LPS) on gram-negative bacteria and induces their death. This study examined plasma BPI concentration levels in healthy newborns and in newborns with clinical sepsis, and the ability of PMN from preterm and term infants to release BPI. We also studied the release of myeloperoxidase (MPO), and the surface expression of adhesion molecule CD11b on PMN. In infants with clinical sepsis, plasma BPI concentration was higher, 27.8 microg/L [8.6-883; median (range)] (n = 11), than in healthy term infants 8.9 microg/L (3.9-179) (n = 17), and in adults 7.3 microg/L (0.7 -18.4) (n = 15); p = 0.014, Kruskal-Wallis. In preterm infants (n = 8), the ability of PMN to release BPI in vitro after stimulation with PMA was 8.8, in term infants it was 15.9 (n = 29; p > 0.05 vs. preterm infants) and in adults 23.4 ng/10(6) PMN (n = 15; p = 0.024 and p > 0.05 vs. preterm and term infants, respectively). The corresponding values of MPO were 20.0 ng/10(6) (11.3-46.7) in preterms, 19.0 ng/10(6) (2.2-223.7) in terms, and 27.8 ng/10(6) (9.1-80.7) in adults; p = 0.67 between groups. In infants with clinical sepsis, CD11b level was higher, 292 RFU (234-403) than the basal CD11b expression levels in healthy newborn infants, 116 RFU (76-145); P = 0.0001. FMLP-stimulated PMN CD11b expressions in preterm cord blood, 1071 RFU (552-1286) and in term cord blood, 918 (567-1472) were on the same level, but lower than that in adult blood, 1592 (973-1946); p < 0.001, ANOVA. Our findings suggest that in preterm infants the ability to release BPI is lower than in adults and term infants. These findings suggest that premature neonates have an impaired ability to mobilize BPI, possibly contributing to their marked susceptibility to infections with Gram-negative bacteria.     

Asymmetric dimethylarginine in ELBW newborns exposed to chorioamnionitis

We measured circulating ADMA concentrations in a group of very premature newborns at birth and during the first week of life.ADMA levels resulted significantly higher in infants born to mothers with histologic chorioamnionitis than in infants delivered for other maternal or fetal indications, both at birth and through the first week of life.We speculate that ADMA might be involved in the complex biological events associated with fetal exposure to chorioamnionitis.     

Nitric oxide levels in preterm and term infants and in premature infants with bacteremia

OBJECTIVE: To determine the serum nitric oxide levels in healthy neonates and in infants with bacteremia. METHODS: We performed a prospective study in a tertiary neonatal intensive care unit. The serum nitric oxide levels were measured in all infants at birth (basal) and in the infected neonates also on the first 2 days of bacteremia. RESULTS: Thirty-three neonates (10 term, 23 preterm) were included. Eleven preterm infants (mean gestational age 27 weeks) had bacteremia. The main blood culture isolates included coagulase-negative staphylococci (n=4), Klebsiella pneumoniae (n=3), and Escherichia coli (n=3). The serum nitric oxide levels increased during infection in 10 infants (p <0.008). The mean nitric oxide level before infection was 44 microM and during infection 96 microM (p=0.008). In the healthy babies, the mean nitric oxide level was 26 microM in those with a gestational age <27 weeks, 44 microM in those born between 28 and 36 weeks of gestation, and 63 microM in term infants. CONCLUSIONS: Bacteremic preterm infants produce significantly higher amounts of nitric oxide. The basal nitric oxide levels at birth may be correlated with gestational age.     

A randomized controlled trial of fluid supplementation in term neonates with severe hyperbilirubinemia

OBJECTIVE: To evaluate the effectiveness of fluid supplementation in decreasing the rate of exchange transfusion and the duration of phototherapy in term neonates with severe nonhemolytic hyperbilirubinemia. STUDY DESIGN: This was a randomized controlled trial conducted in a tertiary care referral unit in northern India. Seventy-four term neonates with severe nonhemolytic hyperbilirubinemia (total serum bilirubin > 18 mg/dL [308 micromol/L] to < 25 mg/dL [427 micromol/L]). The subjects were randomized to an "extra fluids" group (intravenous fluid supplementation for 8 hours and oral supplementation for the duration of phototherapy; n = 37) or a control group (n = 37). RESULTS: At inclusion, 54 infants (73%) had high serum osmolality, including 28 (75%) in the extra fluids group and 26 (70%) in the control group. The proportion of infants who underwent exchange transfusion was lower in the extra fluids group than in the control group: 6 (16%) versus 20 (54%)(P = .001; relative risk = 0.30; 95% confidence interval = 0.14 to 0.66). The duration of phototherapy was also shorter in the extra fluids group: 52 +/- 18 hours versus 73 +/- 31 hours (P = .004). CONCLUSION: Fluid supplementation in term neonates presenting with severe hyperbilirubinemia decreased the rate of exchange transfusion and duration of phototherapy.     

Successful breastfeeding after discharge of preterm and sick newborn infants

AIM: To determine the extent and duration of breastfeeding in preterm and sick newborn infants admitted to a level IIb neonatal unit (NU). METHOD: Hospital-based follow-up of 1730 infants born in 1996, 2001 and 2004, and studied from discharge to 6 months of post-natal age. RESULTS: At discharge from the NU, 98% of term (n = 945) and 92% of preterm (n = 785) infants were exclusively or partly breastfed. Exclusive breastfeeding increased at 2 months of corrected post-natal age and 78% of term infants were still exclusively or partly breastfed at 6 months of corrected post-natal age. Duration of breastfeeding among preterm infants was significantly shorter than in infants born at term. However, even among extremely preterm infants with a gestational age <28 weeks, 41% were still breastfeeding, exclusively or in part, at 6 months of post-natal age. There was no difference in breastfeeding after neonatal care in 1996 as compared to 2004. Moreover, the study showed that the breastfeeding after neonatal care differed only slightly from population data for all infants in Sweden. CONCLUSION: Breastfeeding can be successfully established in most preterm and previously sick neonates.     

Predictive value of umbilical cord blood bilirubin for postnatal hyperbilirubinaemia

AIM: The study investigated the predictive value of umbilical cord serum (UCS) bilirubin for the postnatal course of bilirubinaemia in healthy term and near-term newborns. METHODS: Term appropriate-for-gestational-age (AGA; n=1100), small-for-gestational-age (SGA; n=163) and near-term infants (GA 34-36 wk; n=78) were included and separated according to their UCS bilirubin levels, starting from <20 (group 1), 20-<30 (2), 30-40 (3) and >40 (4) micromol/l. The newborns were followed for at least 5 postnatal days, and UCS bilirubin values were correlated with the development of hyperbilirubinaemia and phototherapy (PT) treatment. RESULTS: A clear relation between UCS bilirubin and the development of hyperbilirubinaemia was found in all three patient populations. None of the 75 AGA patients of group 1 developed postnatal bilirubin values above 300 micromol/l, whereas 0.3, 3.4 and 8.6% of the patients in groups 2-4, respectively, did so. The frequency of PT increased from 0% in group 1 up to 9.6% in group 4. For the prediction of further need of PT using a UCS bilirubin cut-off level of 30 micromol/l, we found a sensitivity of 90% and a negative predictive value of 99.1%, indicating that all patients with UCS bilirubin values below 30 micromol/l (443/1100 or 40.2%) were at a very low risk of developing dangerous hyperbilirubinaemia. Similar results were obtained in SGA children with a sensitivity of 94.1% and a negative predictive value of 98.6%. In comparison to term newborns, we generally found higher bilirubin values in preterms. A total of 6.4% of preterm children developed bilirubin values over 300 micromol/l, compared with 3% of term children, and 47.4% of preterms had to be treated with PT. Predicting the need of PT by using a UCS bilirubin cut-off level of 30 micromol/l revealed a sensitivity of 70.3% and a negative predictive value of 65.6%. CONCLUSION: These data suggest that UCS bilirubin is useful in predicting the postnatal bilirubin values in term and near-term newborns. We presume that the use of UCS bilirubin values may help detect infants at low risk for postnatal hyperbilirubinaemia and minimize an unnecessary prolongation of hospitalization.     

不对称二甲基精氨酸和新生儿相关疾病的关系

不对称二甲基精氨酸(ADMA)是一氧化氮合酶(NOS)的内源性竞争性抑制剂,是血管内皮功能不全的危险因子.近年来研究发现,ADMA不仅是预测急性心血管疾病的危险因子,而且是一种新的预测危重疾病及死亡的危险因子.在动物实验及体外实验发现,外源性ADMA能明显改变肺功能,诱导细胞凋亡.在缺氧、PPHN、需机械通气的早产儿、脑损伤中,ADMA水平均升高.ADMA可能是预测新生儿严重并发症和死亡的独立危险因子.     

Postnatal changes in maternal and neonatal plasma antioxidant vitamins and the influence of smoking

OBJECTIVE: To study the postnatal changes in the plasma concentrations of fat soluble antioxidant vitamins and malondialdehyde (MDA) in mothers and their newborns and their relation to smoking. DESIGN: Prospective cohort study. SETTING: Tertiary perinatal centre. SUBJECTS: Eighteen non-smoking and 14 smoking mothers and 33 infants. MAIN OUTCOME MEASURES: Plasma concentrations of vitamins E, A, and beta-carotene and MDA were measured in mothers and infants at delivery and on day 4 post partum. RESULTS: Neonatal plasma levels of vitamins E, A, and beta-carotene were significantly lower than maternal levels both at delivery and on day 4 in both groups. There was a significant postnatal increase in plasma vitamin E levels in smoking mothers and neonates of both groups. A significant postnatal increase in maternal, but not neonatal, plasma vitamin A was noted in both groups. Cord plasma vitamin E levels were significantly lower in infants of smoking mothers (mean 4.7 v 6.5 micromol/l, p = 0.041). Plasma MDA was paradoxically lower in smoking mothers at delivery (3.19 v 4.01 micromol/l, p = 0.03) and on day 4 (1.37 v 3.29 micromol/l, p = 0.005) and in infants of the smoking group on day 4 (2.18 v 3.12 micromol/l, p = 0.014). Also, there was a significant postnatal fall in plasma MDA levels on day 4 in mothers and infants in the smoking group. CONCLUSIONS: The postnatal changes in plasma vitamin E were more pronounced in the smoking group. The postnatal changes in plasma vitamins A and beta-carotene were similar in both groups. The rapid decline in plasma MDA in smoking mothers and their infants suggests withdrawal of oxidative stress from smoking around delivery. This coincided with the increase in plasma vitamin E.     

PLASMA PANCREATIC POLYPEPTIDE IN THE HUMAN NEONATE

Abstract. Lucas, A., Adrian, T. E., Bloom, S. R. and Aynsley-Green, A. (University Department of Paediatrics, John Radcliffe Hospital, Oxford and Hammersmith Hospital, London). Plasma pancreatic polypeptide in the human neonate. Acta Paediatr Scand, 69: 211, 1980.—Plasma pancreatic polypeptide (PP) concentrations have been studied in 197 healthy term and preterm infants. At birth plasma concentrations were lower than those found in the young fasting adult ( p > 0.01), but by the sixth postnatal day in both term and preterm infants basal concentrations had risen to adult levels. In preterm infants, who were studied at two further postnatal ages, 13 and 24 days, basal plasma PP concentrations peaked at 13 days with levels that were over twice those seen in fasting adults ( p > 0.005). However, the marked PP elevations following feeding that have been reported in adults, were not seen in any of the groups of neonates studied. PP physiology thus appears to differ in neonates and adults. These findings may be relevant to adaptation to postnatal life.