Erythrocyte insulin binding in preterm newborn infants

To characterize the erythrocyte insulin receptor in newborn infants we studied the binding of 125I-insulin to the erythrocytes from 42 preterm infants (14 at birth, 14 aged 2-7 days, and 14 aged 8-16 days) with a mean gestational age of 34.1 wk, and from 32 term infants (16 at birth and 16 aged 2-7 days). The insulin binding to cord blood erythrocytes from preterm infants was significantly higher than that of cord blood cells from term infants and to postnatal cells from preterm as well as term infants. The erythrocytes from preterm infants aged 2-7 days bound more insulin than cells from preterm infants aged 8-16 days. The maximum insulin binding (specific insulin binding at tracer concentration of insulin) correlated negatively with the gestational age both at birth and over the 1st postnatal wk. In the preterm infants there was a strong negative correlation between the maximum insulin binding and postnatal age. The enhanced insulin binding to cord blood erythrocytes from preterm infants was due to both an increased receptor concentration and a high affinity for insulin. The increased affinity persisted over the 1st wk of life. In preterm infants older than 1 wk the insulin binding characteristics were basically similar to those in term newborn infants. In all infants studied the receptor concentration seemed to be postnatal age dependent while the receptor affinity was gestational age dependent. No correlation was found between the insulin binding data and the plasma concentrations of immunoreactive insulin or C-peptide.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of gestational age upon prealbumin and retinol binding protein in preterm and term infants

The relationships between maternal and umbilical cord levels of prealbumin and retinol binding protein (RBP) were studied in 68 mothers and in their appropriate-for-gestational-age neonates delivered between 25 and 42 weeks gestation. Arterial and venous concentrations of prealbumin and RBP in cord sera were also studied in a subsample of eight infants. In cord sera, prealbumin and RBP levels increased with gestational age (prealbumin, r = 0.47; RBP, r = 0.40, p less than 0.01), and were significantly different in neonates born at term compared to those born prematurely (mean +/- SD, prealbumin 12.0 +/- 3.9 mg/dl vs. 8.8 +/- 2.3 mg/dl, p less than 0.001; RBP, 2.3 +/- 0.8 vs. 1.8 +/- 0.5 mg/dl, p less than 0.005). No significant differences between arterial and venous concentrations of prealbumin and RBP were observed in cord blood. In maternal blood, serum prealbumin and RBP concentrations did not increase with length of gestation (25-42 weeks). Maternal prealbumin was not correlated significantly with infants' cord serum levels; the correlation coefficient for RBP was 0.29, p less than 0.05. Maternal prealbumin and RBP serum levels were approximately twice the values seen in neonates born both at term and prematurely. Although the difference between premature and full-term cord levels of prealbumin and RBP may reflect an increase in hepatic protein synthesis that occurs with maturation of the fetus and/or a change in placental function after 37 weeks gestation, neither of these factors sufficiently explains the variance in neonatal prealbumin and RBP levels.     

C-reactive protein and bacterial infection in preterm infants

Serum C-reactive protein (CRP) concentration was measured by a new solid phase ligand-binding radiometric monoclonal antibody immunoassay in a prospective study of 193 consecutively born preterm infants. In 104 with no clinical or laboratory evidence of infection the median CRP in cord serum was 0.125 mg/l (range 0.011–6.0 mg/l), at 24 h it was 1 mg/l (0.016–7.0) and at 48 h 2 mg/l (0.400–8.0). The present highly sensitive assay has enabled these normal ranges to be defined for the first time, at levels below the threshold of non-labelled immunoassays and of all commercially available CRP assays. The values in cord serum were significantly lower than in normal healthy adults (median 0.8 mg/l, range 0.07–29 mg/l,n=468) [20]. Arterial catheterisation and endotracheal intubation, in the absence of infection, did not appear to elevate CRP, nor did cerebral germinal layer or intraventricular haemorrhage. Among nine infants with confirmed septicaemia eight had a serum CRP level raised at least once during the first 48 h and serum CRP in the other one increased 250-fold in 24 h before treatment was started. Using this assay, serum CRP is a useful and rapidly available adjunct to clinical assessment in diagnosis and exclusion of bacterial infection in the early neonatal period, has encouraged us to withhold or discontinue antibiotics and also has a role in monitoring response to treatment.     

Optimal protein and energy intakes in preterm infants

There is compelling evidence that current nutritional practice fails to provide sufficient dietary protein for preterm infants, especially extremely and very low birth weight infants. Nutrient requirements can be estimated by a variety of techniques, but most suggest that these infants will require a protein intake of 3.5-4.0 g/kg/d. Even when these infants are able to tolerate full enteral feeds, most currently available artificial milk formula or breast milk fortifiers will not ensure these protein requirements are met except when fed at high volumes. Energy requirements on the other hand may be currently met, and evidence from controlled studies suggests that intakes higher than 110-135 kcal/kg/d might not be beneficial. The data from studies on neonatal adiposity outcomes, and from studies examining relationship between early growth and later cardiovascular outcome, also suggest that excess nutrient intake might be harmful. In the light of this data, optimal intakes and protein-energy ratios require re-appraisal.     

GTP-dependent protein(Gs) activity in preterm infants.

In a previous study, we showed a renal resistance to PTH in preterm infants during their 1st week of life. We proposed it could explain early neonatal hypocalcemia. Such renal resistance is well known in type 1 pseudohypoparathyroid patients and is explained by a defect of stimulatory GTP-dependent protein (Gs). To determine if functional immaturity in the Gs protein could be involved in PTH resistance, we studied 27 newborn babies: 7 full-term and 20 preterm babies. Biological activity of the Gs unit was determined on days 1, 3 and 10 after delivery by bioassay. No correlation was found between the Gs unit activity and either gestation or birth weight at these dates. Eight infants had hypocalcemia and their Gs unit activity did not differ from those with normocalcemia. Furthermore, we showed that the Gs unit is active from 29 weeks of gestation. We conclude that the Gs protein appears not to be involved in the pathophysiology of early renal resistance to PTH and therefore in early neonatal hypocalcemia.     

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??Objective To investigate the predictive value of lipopolysaccharide binding protein ??LBP?? in early diagnosis of preterm infection with premature rupture of membrane??PROM??. Methods Totally 93 preterm infants with PROM were enrolled in this study?? and were divided into infection group ??45 cases?? and non-infection group ??48 cases?? according to the discharge diagnosis. Their serum LBP levels were detected within 24 hours after birth. High-sensitivity C-reactive protein ??hs-CRP???? procalcitonin ??PCT?? and interleukin-6 ??IL-6?? levels were compared with LBP. Receiver operator characteristic curve ??ROC?? was drawn and the area under the curve ??AUC?? was calculated. Each parameter was evaluated for the diagnosis of early-onset infection in preterm infants with PROM. In addition?? according to the severity of the disease infection group was further divided into severe infection group??21 cases?? and general infection group??24 cases??. LBP levels were detected in two groups of premature infants to assess the value of LBP in the diagnosis of premature infants with premature rupture of membranes. Results The serum levels of IL-6?? PCT and LBP in the infection group were significantly higher than those in the non-infection group. There was no significant difference on serum levels of hs-CRP between the two groups. The level of LBP in the severe infection group was higher than that in the general infection group?? and the difference between the two groups was statistically significant. The AUC of ROC for LBP ??0.974?? in early-onset bacterial infection of preterm infants with PROM was the highest?? PCT ??0.694?? second?? IL- 6 ??0.588?? third?? and hs-CRP ??0.478?? was the lowest. Conclusion Serum level of LBP is superior to hs-CRP and PCT in the diagnosis of early-onset bacterial infection in preterm infants with PROM. LBP can be used as a useful index for the early diagnosis of bacterial infection in preterm infants with PROM. LBP levels can evaluate the severity of premature premature infection in preterm premature rupture of membranes.     

Studies in renal response to various protein intakes in preterm infants

The renal effects of two diets--breast-milk and breast-milk with extra human protein (7 g/l breast-milk)--were compared in very low birth weight infants with a gestational age of 26 to 30 weeks. When the infants were given the high protein diet for one week the glomerular filtration rate (GFR) increased significantly more than when breast-milk alone was given. Sodium clearance showed a similar increase in proportion to the GFR during the two diets. The high protein diet raised the urine osmolality moderately in all individuals, while the diuresis remained unchanged. The data in the present study indicate that the function of the immature kidney is influenced by the amount of protein in the diet. However, the long-term renal effects in preterm infants maintained on a high protein intake remain unknown.     

Hypotension in preterm infants

PURPOSE: Hypotension is a frequent occurrence in sick preterm neonates. It is important to appropriately recognise and treat hypotension in preterm infants due to the possible association with short and long term adverse outcomes. SEARCH STRATEGY: An extensive search for relevant articles was carried out on PubMed, Embase and Cochrane database of systematic reviews. Cross references were hand searched. CONCLUSIONS: The pathophysiology hypotension in preterm infants is multifactorial. Hypovolemia plays only a minor role in the absence of overt fluid losses. Cardiac dysfunction seems to be a factor in some neonates. Assessment of hypotension should be based on an overall clinical condition. Overzealous fluid administration seems to be associated with adverse outcomes and should be avoided in the absence of obvious fluid losses. Inotropes should be used if fluid boluses fail to correct hypotension. Dopamine is the most effective inotrope. Dobutamine can be used as add on therapy or as first line if cardiac dysfunction is an obvious cause. Evidence points to hypocortisolism in at least some hypotensive infants. Steroids have been used successfully in inotrope-resistant hypotension in some infants. Steroids should be used judiciously since there have been concerns about adverse neurological outcome in preterm infants who received steroids in the neonatal period.     

Hydrolysed protein accelerates the gastrointestinal transport of formula in preterm infants

Vomiting, large gastric residuals and abdominal distension are common in very immature infants on formula feeding. The present trial investigated whether a protein hydrolysate formula reduces the gastrointestinal transit time in preterm infants. Fifteen preterm infants (median gestational age 29 (24-32) wk, birthweight 1241 (660-1900) g, postnatal age 18 (5-54) d) on full enteral feeds (>150 ml/kg*d) were enrolled. It was hypothesized that the gastrointestinal transit time is at least 2 h shorter when protein hydrolysate formula is fed compared with standard preterm formula. In a randomized cross-over design study, each formula was fed for 5 d. On days 4 and 9 the gastrointestinal transit time was estimated using carmine red. The protein hydrolysate formula had a markedly shorter gastrointestinal (p = 0.0022, two-sided Mann-Whitney U test). Conclusion: The hydrolysate protein formula accelerated gastrointestinal transit of milk and stools, but whether hydrolysate formulas enable a more rapid establishment of full enteral feeding in preterm infants needs to be investigated. transit time (9.8 h) than the standard formula (19 h)     

丝裂原活化蛋白激酶与早产儿慢性肺疾病

早产儿慢性肺疾病是早产儿吸入高浓度氧、机械通气治疗和肺部感染后最常见的合并症.其详细的发病机制尚未完全明了,病理主要表现为早期的炎症反应,晚期的肺泡融合及间质成纤维细胞增生.丝裂原活化蛋白激酶(MAPK)是真核细胞内重要的信号传导通路,近来研究发现MAPK通过参与词节细胞炎症、增殖、分化、生存和凋亡等多种生物学行为,促进了早产儿慢性肺疾病的发生.     

丝裂原活化蛋白激酶与早产儿慢性肺疾病

早产儿慢性肺疾病是早产儿吸入高浓度氧、机械通气治疗和肺部感染后最常见的合并症.其详细的发病机制尚未完全明了,病理主要表现为早期的炎症反应,晚期的肺泡融合及间质成纤维细胞增生.丝裂原活化蛋白激酶(MAPK)是真核细胞内重要的信号传导通路,近来研究发现MAPK通过参与词节细胞炎症、增殖、分化、生存和凋亡等多种生物学行为,促进了早产儿慢性肺疾病的发生.     

丝裂原活化蛋白激酶与早产儿慢性肺疾病

早产儿慢性肺疾病是早产儿吸入高浓度氧、机械通气治疗和肺部感染后最常见的合并症.其详细的发病机制尚未完全明了,病理主要表现为早期的炎症反应,晚期的肺泡融合及间质成纤维细胞增生.丝裂原活化蛋白激酶(MAPK)是真核细胞内重要的信号传导通路,近来研究发现MAPK通过参与词节细胞炎症、增殖、分化、生存和凋亡等多种生物学行为,促进了早产儿慢性肺疾病的发生.     

Lipopolysaccharide binding protein is a potential marker for invasive bacterial infections in children

BACKGROUND: The aim of this study was to test the hypothesis that elevated lipopolysaccharide binding protein (LBP) serum concentration is a useful marker in the early diagnosis of invasive bacterial infection in children. We measured LBP in serum and cerebrospinal fluid (CSF) of children with proven invasive infection caused by Haemophilus influenzae, Streptococcus pneumoniae and Neisseria meningitidis. PATIENTS AND METHODS: Samples were collected from 39 children (aged 2 months to 17 years) with bacterial sepsis (n = 19) or meningitis (n = 20). Bacterial infection was diagnosed when a blood or CSF culture was positive and clinical signs of invasive infection were present. The control group consisted of serum (n = 60) and CSF (n = 19) samples from children with neurologic disease, juvenile idiopathic arthritis or viral infection. In 10 patients with bacterial infection, follow-up samples (24 and 48 hours) were available. LBP values were measured by an immunochemiluminescence analyzer (IMMULITE; DPC Biermann, Bad Nauheim, Germany) and compared with tumor necrosis factor-alpha and interleukin-8 concentrations. RESULTS: The median LBP serum concentrations in patients with bacterial infection were markedly elevated compared with the control groups (45.0 [33.1-55.2] versus 8.3 [6.8-10.1] microg/mL [median and 5-95% confidence interval]; P < 0.0001). Follow-up serum values of LBP were persistently elevated despite adequate antibiotic treatment, whereas tumor necrosis factor-alpha and interleukin-8 concentrations decreased. In contrast, LBP concentrations in the CSF were below the detection limit of 0.5 microg/mL in 67% of patients with bacterial meningitis (median <0.5 microg/mL), whereas tumor necrosis factor-alpha and interleukin-8 levels were highly elevated. CONCLUSION: LBP serum concentration is elevated in serum of children with invasive bacterial infection and could be a promising diagnostic marker.     

Basal insulin secretion and erythrocyte insulin binding in preterm and term newborn infants

To study the ontogeny of the insulin secretion and the erythrocyte insulin receptor we measured plasma immunoreactive insulin and C-peptide concentrations and the binding of [125I]-insulin to the erythrocytes in cord blood from 16 preterm and 16 term infants. 20 normal-weight adults were also studied. The C-peptide concentrations and the molar ratio of C-peptide to insulin were lower in the newborn infants than in the adults. The immunoreactive insulin correlated positively with birth weight in the term infants. The insulin binding to erythrocytes from the newborn infants was increased when compared to the adults. Erythrocytes from the preterm infants bound more insulin than the cells from the term infants. There was a strong negative correlation between insulin binding and gestational age. In the term infants, plasma C-peptide correlated negatively with the insulin binding. The increased binding to erythrocytes from the term infants was due to an increase in the receptor concentration. The high insulin binding in the preterm infants was a result of both an increased receptor concentration and affinity. These data suggest that the basal insulin secretion is similar in preterm and term infants and that the clearance of insulin is decreased in newborn infants. The increased insulin binding in newborn infants may be a mechanism by which the growth stimulatory effect of insulin in fetal life is mediated.