Marta M. G. B. Mataloun

Lung morphometry, collagen and elastin content: changes after hyperoxic exposure in preterm rabbits

INTRODUCTION Elastic and collagen fiber deposition increases throughout normal lung development, and this fiber network significantly changes when development of the lung is disturbed. In preterm rats and lambs, prolonged hyperoxic exposure is associated with impaired alveolization and causes significant changes in the deposition and structure of elastic fibers. OBJECTIVES To evaluate the effects of hyperoxic exposure on elastic and collagen fiber deposition in the lung interstitial matrix and in alveolarization in preterm rabbits. METHODS After c-section, 28-day preterm New-Zealand-White rabbits were randomized into 2 study groups, according to the oxygen exposure, namely: Room air (oxygen = 21%) or Oxygen (oxygen ≥ 95%). The animals were killed on day 11 and their lungs were analyzed for the alveolar size (Lm), the internal surface area (ISA), the alveoli number, and the density and distribution of collagen and elastic fibers. RESULTS An increase in the Lm and a decrease in the alveoli number were observed among rabbits that were exposed to hyperoxia with no differences regarding the ISA. No difference in the density of elastic fibers was observed after oxygen exposure, however there were fewer collagen fibers and an evident disorganization of fiber deposition. DISCUSSION This model reproduces anatomo-pathological injuries representing the arrest of normal alveolar development and lung architecture disorganization by just a prolonged exposition to oxygen. CONCLUSIONS In the preterm rabbit, prolonged oxygen exposure impaired alveolization and also lowered the proportion of collagen fibers, with an evident fiber network disorganization.

Effect of postnatal malnutrition on hyperoxia-induced newborn lung development

Several factors are associated with bronchopulmonary dysplasia. Among them, hyperoxia and lung immaturity are considered to be fundamental; however, the effect of malnutrition is unknown. Our objective was to evaluate the effects of 7 days of postnatal malnutrition and hyperoxia on lung weight, volume, water content, and pulmonary morphometry of premature rabbits. After c-section, 28-day-old New Zealand white rabbits were randomized into four groups: control diet and room air (CA, N = 17), control diet and > or = 95% O2 (CH, N = 17), malnutrition and room air (MA, N = 18), and malnutrition and > or = 95% O2 (MH, N = 18). Malnutrition was defined as a 30% reduction of all the nutrients provided in the control diet. Treatments were maintained for 7 days, after which histological and morphometric analyses were conducted. Lung slices were stained with hematoxylin-eosin, modified orcein-resorcin or picrosirius. The results of morphometric analysis indicated that postnatal malnutrition decreased lung weight (CA: 0.83 +/- 0.19; CH: 0.96 +/- 0.28; MA: 0.65 +/- 0.17; MH: 0.79 +/- 0.22 g) and water content, as well as the number of alveoli (CA: 12.43 +/- 3.07; CH: 8.85 +/- 1.46; MA: 7.33 +/- 0.88; MH: 6.36 +/- 1.53 x 10-3/mm) and elastic and collagen fibers. Hyperoxia reduced the number of alveoli and increased septal thickening and the mean linear intercept. The reduction of alveolar number, collagen and elastic fibers was intensified when malnutrition and hyperoxia were associated. These data suggest that dietary restriction enhances the magnitude of hyperoxia-induced alveolar growth arrest and lung parenchymal remodeling. It is interesting to consider the important influence of postnatal nutrition upon lung development and bronchopulmonary dysplasia.

Respostas pulmonares à restrição nutricional e à hiperoxia em coelhos prematuros

OBJETIVOS: Este modelo experimental foi desenvolvido para analisar os efeitos da restricao nutricional e da hiperoxia, durante 11 dias, sobre o peso e a morfometria pulmonares, em coelhos prematuros. METODOS: Apos cesarea, coelhos New Zealand White com idade gestacional de 28 dias foram randomizados nos seguintes grupos: dieta controle e ar ambiente, dieta controle e hiperoxia (> 95% O2), restricao nutricional e ar ambiente e restricao nutricional e hiperoxia (>95% O2). A restricao nutricional foi obtida com uma reducao em 30% de todos os nutrientes da dieta controle. As lâminas de pulmao foram coradas com hematoxilina-eosina, resorcina-orceina modificada e picrosirius, sendo posteriormente realizada a analise morfometrica RESULTADOS: Observou-se um menor ganho de peso no grupo restricao nutricional e hiperoxia (p < 0,001) a partir do quarto dia e, no grupo restricao nutricional e ar ambiente (p < 0,001), a partir do sexto dia de vida, em relacao aos respectivos grupos controles. A restricao nutricional reduziu o numero de alveolos (p < 0,001) e o deposito de colageno (p < 0,001). A hiperoxia produziu uma reducao do numero de alveolos (p < 0,001) e do deposito de colageno (p < 0,001), alem de maiores intercepto linear medio (p < 0,05) e espessamento de septos inter-alveolares (p < 0,001). A restricao nutricional associada a hiperoxia intensificou a reducao do numero de alveolos (p < 0,001) e do deposito de colageno (p < 0,001). CONCLUSOES: A restricao nutricional intensificou as alteracoes morfometricas pulmonares produzidas pela hiperoxia, especialmente em relacao a alveolizacao e deposito de colageno.

Hydronephrosis in Schinzel-Giedion syndrome: an important clue for the diagnosis

Schinzel-Giedion syndrome is a rare autosomal recessive disorder characterized by coarse facies, midface retraction, hypertrichosis, multiple skeletal anomalies, and cardiac and renal malformations. Craniofacial abnormalities of this syndrome sometimes resemble a storage or metabolic disease. The pathogenesis of the disease remains unknown. The objective of this report was to emphasize the importance of congenital bilateral hydronephrosis for the diagnosis of Schinzel-Giedion syndrome. We describe the first Brazilian case of a newborn with typical facies, generalized hypertrichosis, cardiac and skeletal anomalies, and bilateral hydronephrosis detected during pregnancy and confirmed later by abdominal ultrasonography. Chromosomal constitution was normal. Of the 35 cases already reported in the literature, 31 presented hydronephrosis, which is considered an important clue in diagnosis. If Schinzel-Giedion syndrome were indexed as a cause of congenital hydronephrosis, its identification would be greatly facilitated, since the majority of the other findings in Schinzel-Giedion syndrome are nonspecific and common to many genetic syndromes.

Predictive value of the "Clinical Risk Index for Babies" for the risk of neonatal death

OBJECTIVE Several indicators, mainly birthweight and gestational age, have been used to predict the mortality risk in neonatal intensive care units. In order to assess the potential value of CRIB in predicting neonatal mortality, the score was used over the first 12 hours of life of the newborns admitted to this unit, during the year of 1996. METHOD The inclusion criteria consisted of all infants without inevitably lethal congenital malformations, birthweight below 1,500 g and/or gestational age less than 31 weeks. Newborn children who died within 12 hours after delivery were excluded. The CRIB score covers birth weight, gestational age, the presence of congenital malformations (not inevitably lethal) and three indexes of physiological status during first 12 hours after birth-maximum and minimum appropriate fraction of inspired oxygen and maximum (most acidotic) base excess. RESULTS In a prospective cohort, seventy one newborn children were studied. The birthweight (average) was 1,119 +/- 275.6 g, gestational age 30 weeks 4/7 +/- 2 weeks 3/7; male (57%); Apgar 1(0) min. score < or = 3 (36.2%) and Apgar 5 degrees min. score < 5 (5.8%). The mortality rate was 29.6% (gold standard). But mortality rate by birthweight less than 1,000 gr. or gestational age lower than 29 weeks was 60.0% and for the CRIB score above 10 was 100%. DISCUSSION The specificity and predictive positive values for CRIB score above 10 were greater than any other two parameters. The area under the receiver operating characteristic (ROC) curve for predicting death was significantly greater for CRIB than for birthweight alone. It was concluded that the CRIB score is a better predictive indicator for mortality than are birthweight and gestational age.

Use of corticosteroids and the outcome of infants with bronchopulmonary dysplasia.

UNLABELLED Ventilator-dependent premature infants are often treated with dexamethasone. Several trials showed that steroids while improve pulmonary compliance and facilitate extubation, some treated infants may have adverse effects, such as alterations of growth curves. We conducted this retrospective study to evaluate the effects of steroids on mechanical ventilation, oxygen therapy, hospital length stay and mortality, in ventilator-dependent infants with bronchopulmonary dysplasia (BPD) (defined as the need of oxygen supplementation at 28 days of life). Twenty-six newborns with BPD were evaluated during 9 - 42 days postpartum (mean = 31 days) and were divided into two groups: Group I - 14 newborns that did not receive dexamethasone, and Group II - 12 newborns that received dexamethasone at 14 - 21 days of life. Dexamethasone was given at a dose of 0.25 mg per kilogram of body weight twice daily intravenously for 3 days, after which the dose was tapered. RESULTS There were no statistically significant differences in the mean length of mechanical ventilation (Group I - 37 days, Group II - 35 days); oxygen supplementation (Group I - 16 days, Group II - 29 days); hospital stay (Group I - 72 days, Group II - 113 days); mortality (Group I - 35.7%, Group II - 41.6%). At birth, Group II was lighter (BW: Group I - 1154 grams +/- 302, Group II - 791 grams +/- 165; p < 0.05) and smaller (height: Group I - 37.22 cm +/- 3.3, Group II - 33.5 +/- 2.4; p< 0.05) than Group I. At 40 weeks, there were no statistically significant differences between groups in relation to anthropometric measurements. CONCLUSIONS The use of corticosteroids in bronchopulmonary dysplasic infants may influence the somatic growth during its use. However, after its suspension, a recovery seems to occur, suggesting that its influence could be transitory.

Effects of corticosteroids in very low birth weight newborns dependent on mechanical ventilation

UNLABELLED Corticosteroids have been used in bronchopulmonary dysplasia prevention because of their antiinflammatory effects. Among their effects is a decrease in the incidence of bronchopulmonary dysplasia. However, short- and long-term side effects have been detected in preterm newborns. PURPOSE To analyze the effects of corticosteroids on bronchopulmonary dysplasia, length of stay, mortality, growth, as well as the adverse effects in very low birth weight newborns between 10 and 14 days of life and dependent on mechanical ventilation. METHODS Cohort study. All newborns with a birth weight under 1500 g, mechanical ventilation-dependent between 10 and 14 days of life, during the period January 2000 and June 2001 were included (n = 38). They were divided into 2 groups: Group I with corticosteroids (n = 16) and Group II without corticosteroids (n = 22). Dexamethasone administration: from the 10th day of life, d1-d3, 0.3 mg/kg/d; d4-d6, 0.2 mg/kg/d; d7-d9, 0.1 mg/kg/d. Respiratory evolution, bronchopulmonary dysplasia (oxygen dependence at 28 days of life), growth pattern and the presence of adverse effects were analyzed. RESULTS The incidence of bronchopulmonary dysplasia was 6.5% (Group I) and 30% (Group II), P = .07. A decrease in growth was detected in Group I compared with Group II (change in weight: Group I--47 g/week, Group II--85.5 g/week, P = .06; change in head circumference: Group I--0.75 cm/week, Group II--1 cm/week, P = .05). CONCLUSION Use of corticosteroids in very low birth weight infants dependent on mechanical ventilation during the first 10 to 14 days of life did not affect the respiratory evolution and occurrence of bronchopulmonary dysplasia, but the velocity of growth was reduced.

Prolonged rupture of the membranes and neonatal infection

OBJECTIVE To evaluate a schedule of assessment at birth of newborn from mothers with prolonged rupture of membranes (PROM >or= 24 hours), based on selected clinical and laboratorial parameters of infection. METHODS Prospective study, including newborns admitted to the Nursery of the Hospital de Clínicas - University of São Paulo from May/1993 to December / 1994, whose mothers had PROM >/or 24 hours. In all newborns white blood cell count (umbilical cord and 24 hours of life) and blood culture of umbilical cord were done. Antibiotics were given to newborns with clinical signs of chorioamnionitis, GA <or= 34 weeks and/or GA> 34 and < 37 weeks, plus at least one risk factor of infection. All newborns were classified into 4 subgroups: I (PROM <or= 48 hours), II (PROM > 48 hours and < 7 days), III (PROM >or= 7 and < 14 days), IV (PROM >or= 14 days). RESULTS The incidence of infection was 38.1% and was more frequent in newborns with GA < 34 weeks (p< 0.05). No statistical significance was noted among the subgroups analysed. Among the risk factors analysed, GA < 34 weeks was the main one. CONCLUSIONS The authors recommend the use of prophylactic antibiotic therapy in newborns from mothers with PROM which have a GA <or= 34 weeks, aiming to decrease the risk of neonatal infection.