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BACKGROUND AND AIMS: Most diseases in premature neonates are secondary to immaturity of various organ systems. Also the inadequate capacity of mitochondrial energy production may play an important role in the neonatal morbidity. SUBJECTS AND METHODS: The activities and amount of respiratory chain (RC) complexes, pyruvate dehydrogenase (PDH) and citrate synthase (CS) were analysed in isolated muscle mitochondria obtained at autopsy in 19 premature neonates using spectrophotometric and radioenzymatic methods and blue-native electrophoresis and Western blotting. Two groups of children recommended for muscle biopsy at the age of 0.5-2 and 3-18 years served as controls. RESULTS: In premature neonates, the activities of RC complexes III, IV, PDH and CS were markedly lower in comparison with older children. On the contrary, the activity of complex I was higher in premature neonates than in older children. The ratios between RC complexes I, II and III and CS were significantly higher in premature neonates in comparison with older children. In addition, the protein amount of RC complexes and PDH subunits were lower in premature neonates in comparison with older children. CONCLUSION: The results of our study document the age-dependent differences in activities of PDH and respiratory chain complexes in early childhood. Lower functional capacity of mitochondrial energy-providing system in critically ill neonates may be explained by combination of various factors including the delay in maturation of PDH and respiratory chain complexes in very premature neonates and increased degradation of mitochondrial proteins in connection with sepsis, tissue hypoperfusion or hypoxemia.

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Extremely preterm infants often develop chronic lung disease (CLD) characterized by heterogeneous aeration; poorly supported, floppy airways; and air trapping. High-frequency jet ventilation (HFJV) with high end-expiratory pressure (optimal lung volume strategy [OLVS]) may improve airway patency, lead to better gas distribution, improve gas exchange, and facilitate extubation. In a pilot trial, this study sought to explore the effect of HFJV on oxygenation, ventilation, and ease of extubation in preterm infants with evolving CLD and refractory respiratory failure (RRF). From September 2002 to October 2004, 12 episodes of RRF developed in 10 ventilated extremely immature infants with evolving CLD (10 on conventional and two on high-frequency oscillation). Chorioamnionitis was confirmed in all infants, patent ductus arteriosus was ligated in five patients, and UREAPLASMA UREALYTICUM was cultured from trachea in four patients. HFJV with OLVS was initiated when oxygenation index (OI) > 10 or exhaled tidal volume (V TE) >or= 7 mL/kg were required to maintain partial pressure of carbon dioxide, arterial (Pa CO2) < 60 mm Hg. Inspiratory time (0.02/s) and frequency (310 to 420/min) were set initially with adjustment of pressure amplitude to keep Pa CO2 between 45 and 55 mm Hg. Ventilatory stabilization and weaning from mechanical ventilation with extubation to nasal continuous positive airway pressure (CPAP) were the goals of this approach. Gas exchange data were analyzed by Analysis of variance for repeated measures. Ten patients on 11 occasions of RRF were extubated to nasal CPAP successfully in a median of 15.5 days. Nine of 10 patients survived (one died of pentalogy of Cantrell), all required supplemental O2 at 36 weeks. Pa CO2 decreased within 1 hour after the initiation of HFJV, and OI decreased by 24 hours. Both remained significantly lower until successful extubation ( P < 0.02). Compared with conventional ventilation or high-frequency oscillatory ventilation, HFJV used with OLVS appears to improve gas exchange and may facilitate weaning from mechanical ventilation (MV) in extremely immature infants with evolving CLD. These encouraging pilot data need to be confirmed in a larger clinical trial.

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Carnitine plays an important role in energetic metabolism. The aim of the study was to characterize the carnitine status in term and preterm newborns with respect to gestational age, birth weight, haematocrit and red blood cell count (RBC). The effect of nutrition on carnitine levels in the first week of life was also studied. Total blood pool of free carnitine (FC), acylcarnitines (AC) and total carnitine (TC) were analysed in whole cord blood and postnatally in capillary blood obtained at the day 4-6 in 33 term newborns and at the day 7-10 in 27 preterm newborns using tandem mass spectrometry. Plasma level of carnitine in the cord blood was measured using radioenzymatic method. Cord plasma levels of FC, AC and TC were higher in preterm newborns in comparison with term newborns (p < 0.01), but the total blood pool of FC and TC in whole cord blood was lower in preterm newborns than in term newborns (p < 0.01) and positive correlation was found between FC and gestational age or birth weight (p < 0.05). In addition, positive correlation was found between AC and red blood cell count or haematocrit (p < 0.05). During the first week of life, blood pool of FC and TC in term newborns and AC and TC in preterm newborns decreased regardless of the type of enteral or parenteral nutrition. Our results indicate that preterm newborns are born with limited carnitine store. Interpretation of carnitine analyses in whole blood relies in addition to gestational age and birth weight on the haematocrit, especially in newborns with anaemia or blood hyperviscosity.

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The experience gained since 1987, through observation of 85 girls with Turner syndrome under growth hormone (GH) treatment, has enabled the analysis of one of the largest cohorts. Our results show that age, karyotype and height reflect the heterogeneity of the patients examined at our growth centre. In 47 girls, followed over 4 years on GH (median dose 0.72 IU/kg/week), the median age was 9.4 years and mean height SDS was -3.55 (Prader) and -0.14 (Turner-specific), while height and other anthropometrical parameters [weight, body mass index, sitting height (SH), leg length (LL) SH/LL, head circumference, arm span] were documented and compared to normative data as well as to Turner-specific references established on the basis of a larger (n = 165) untreated cohort from Tübingen. The latter data are also documented in this article. Although there was a trend towards normalization of these parameters during the observation period, no inherent alterations in the Turner-specific anthropometric pattern occurred. In 42 girls who started GH treatment at a median age of 11.8 years, final height (bone age >15 years) was achieved at 16.7 years. The overall gain in height SDS (Turner) from start to end of GH therapy was 0.7 (+/- 0.8) SD, but 0.9 (+/- 0.6) SD from GH start to onset of puberty (spontaneous 12.2 years, induced 13.9 years) and -0.2 (+/- 0.8) from onset of puberty to end of growth. Height gain did not occur in 12 patients (29%) and a gain of > 5 cm was only observed in 16 patients (38%). Height gain correlated positively with age at puberty onset, duration, and dose of GH, and negatively with height and bone age at the time GH treatment started. Final height correlated positively with height SDS at GH start and negatively with the ratio of SH/LL (SDS). We conclude that, in the future, GH should be given at higher doses, but oestrogen substitution should be done cautiously, owing to its potentially harmful effect on growth. LL appears to determine height variation in Turner syndrome and the potential to treat short stature successfully with GH.

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The authors used assessment of lactic dehydrogenase activity in cerebrospinal fluid to evaluate the severity of hypoxic damage of the CNS of neonates. The highest activity was recorded in infants who died in conjunction with the hypoxic lesion of the CNS. The lowest activity was found in neonates with a permanently normal neurological finding during infancy. From the results ensues the prognostic importance of the above examination for subsequent psychomotor development of children.

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The authors assessed the levels of lactate and 2,3 diphosphoglycerate in the umbilical blood of 105 full-term neonates. A significant increase was found in the levels of 2,3 diphosphoglycerate in newborns of mothers with a history of imminent chronic intrauterine hypoxia. The lactate levels of these newborns were the same as in children of mothers without a history showing a risk of intrauterine hypoxia. The psychomotor development of newborns with increased levels of 2,3 diphosphoglycerate was significantly more altered than in those with normal levels in their first year of life.

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The authors examined 91 neonates with one or several anamnestic signs of intra-partum hypoxia (cardiotocographic record, pH in blood of umbilical artery, Apgar score) and 65 neonates with a normal delivery. When evaluating signs of hypoxia, a very low correlation between the methods used was found. Neurological investigation of all children revealed significant differences in the incidence of neurological abnormalities between groups of hypoxic neonates (whatever method used) and the group of neonates without a history of hypoxia intra partum, but only in the second month. In the other age periods, when the children were subjected to neurological examination (6, 12 months), no differences were found in the frequency of neurological abnormalities between the group of "hypoxic" and normal children.

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Mean beta-endorphin-like immunoreactivity in the plasma of 10 normal women in the 10th month of pregnancy was 144.3 +/- 7.5 ng/l. During labor in 7 women its immunoreactivity was increased and peaked at the time of vaginal delivery (1 162 +/- 69 ng/l). Two hours after delivery, beta-endorphin-like immunoreactivity was significantly decreased (297 +/- 39 ng/l) and after 4 to 5 days was 155 +/- 33 ng/l. Beta-endorphin-like immunoreactivity in the cord plasma (523 +/- 30 ng/l) was significantly lower than in the mother at the time of vaginal delivery and in venous blood of newborns 24 hours post partum was 156 +/- 11 ng/l. The correlation between beta-endorphin-like immunoreactivity in the mother and the cord blood plasma was not determined. At the time of the fetal hypoxia, beta-endorphin-like immunoreactivity in the cord blood plasma was increased (2 741 ng/l). We conclude that immunoreactive beta-endorphin influences a stress reaction in the mother and fetus at the time of labor. During intra-uterine life the fetus probably produces its own immunoreactive-like beta-endorphin independently of the maternal production of this peptide.

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