RESUMO
OBJECTIVES: We studied the left ventricular systolic and diastolic function in preterm infants during the first month of life in comparison with the respective patterns in term neonates. STUDY DESIGN: Serial 2-dimensional/M-mode and Doppler transmitral flow velocity measurements were performed in 20 preterm (gestational age, 32 to 36 weeks) and 25 term infants between days 2 and 5 after birth and at age 1 month. RESULTS: After birth, the early velocity, early integral, early filling fraction, early and atrial velocity ratios, and early and atrial integral ratios were lower in the preterm than in the term infants (P <.01). During the first 4 weeks of life, these values, the atrial velocity, and the atrial integral increased gradually, whereas the atrial filling fraction, diastolic filling time, and deceleration time of early diastolic filling decreased slightly with postnatal age (P <.01) in the preterm infants. At age 1 month their diastolic function reached the level of term infants with the exception of early and atrial integral ratios and atrial filling fraction. The measures of systolic performance were within normal range, but midwall fractional shortening at 2 to 5 days (P <.05), and fractional shortening area (P <.05), as well as midwall fractional shortening (P <.01) at 1 month of age, were slightly inferior in the preterm than in the term infants. During the first month the left ventricular mass and left ventricular mass/body surface area ratio increased more markedly in the preterm than term infants, significantly in both groups (P <.05). CONCLUSIONS: The preterm diastolic patterns represent a transition between the patterns of the fetus and those of term neonates. These changes reflect an improvement in the left ventricular diastolic function, more markedly in relaxation than in compliance. The postnatal increase in the transmitral measures and left ventricular mass suggest marked myocardial adaptation to the extrauterine environment in the preterm infant already during the first month.
Assuntos
Diástole/fisiologia , Recém-Nascido Prematuro/fisiologia , Sístole/fisiologia , Função Ventricular Esquerda/fisiologia , Velocidade do Fluxo Sanguíneo/fisiologia , Desenvolvimento Infantil/fisiologia , Ecocardiografia Doppler , Feminino , Seguimentos , Humanos , Recém-Nascido , Masculino , Estudos Prospectivos , Volume Sistólico/fisiologiaRESUMO
OBJECTIVE: To evaluate the contribution of the type of milk on serum cholesterol ester fatty acids in infants receiving mixed feeding, we analyzed 3-day dietary records and serum cholesterol ester fatty acid composition of 397 seven-month-old infants. STUDY DESIGN: The infants received, in addition to solid food, only one type of milk: human milk (n = 218), a ready-to-use liquid formula (n = 139), a powdered formula (n = 33), or soy formula (n = 7). RESULTS: Mean fat intakes were low and varied from 28% to 31% of energy; the milks provided 43% to 64% of the fat. The mean polyunsaturated/saturated fat ratios of solid foods were from 0.52 to 0.63 and of milks from 0.20 to 0.45. Breast-fed infants' relative serum linoleic acid (18:2n-6) concentration was low (51.2%), whereas infants fed liquid formula had low serum oleic acid (18:1n-9) in accordance with low oleic acid content in that formula. The breast-fed infants had markedly higher serum concentrations of arachidonic acid (20:4n-6) and docosahexaenoic acid (22:6n-3) than the infants fed any of the formulas. CONCLUSION: The typical fatty acid patterns of breast- or formula-fed infants were still evident in 7-month-old infants who already received 60% to 70% of their energy from solid food. Marked differences were seen also in the relative concentrations of docosahexaenoic acid and arachidonic acid despite their small contribution in cholesterol esters.
Assuntos
Aleitamento Materno , Ácidos Graxos/sangue , Alimentos Infantis/análise , Leite Humano/química , Gorduras na Dieta/administração & dosagem , Gorduras/análise , Ácidos Graxos/análise , Feminino , Humanos , Lactente , MasculinoRESUMO
OBJECTIVE: To determine the influence of gender, apolipoprotein E phenotypes, and diet on the interindividual variances in serum lipid and lipoprotein concentrations in children at 7 and 13 months of age. STUDY DESIGN: Prospective randomized intervention trial. Half of 1062 families with 7-month-old infants received dietary and lifestyle counseling aimed at partially replacing saturated fat with mono- and polyunsaturated fat and reducing exposure to other known atherosclerosis risk factors. This study comprises all trial children who at 8 months of age received, in addition to solid food, only breast milk or only formula (N = 553). Forward stepwise multiple regression analysis was used in the evaluation of the contributions of gender, apolipoprotein E phenotype, and diet. RESULTS: Apolipoprotein E phenotypes, gender, and milk type provided independent information concerning serum lipid values at 7 and 13 months of age (three-way ANOVA, p < 0.01). At 7 months, milk type was the most significant predictor of total, non-high-density lipoprotein and high-density lipoprotein cholesterol and apolipoprotein B and A1 concentrations. At 13 months when the effects of gender (5%) and apolipoprotein E type (5%) were excluded, diet predicted only 2% of the variance in serum cholesterol concentration. The apolipoprotein E type predicted 8% of the variance in non-high-density lipoprotein cholesterol concentration and 7% of the variance in apolipoprotein B concentration (p < 0.001), together explaining only 3% of the variance in serum high-density lipoprotein cholesterol and apolipoprotein A1 concentrations. CONCLUSIONS: At 7 months of age diet is an important predictor of serum lipid and lipoprotein concentrations. At the age of 13 months the apolipoprotein E phenotype significantly predicts the concentrations of serum non-high-density lipoprotein cholesterol and apolipoprotein B. However, at both ages apolipoprotein E phenotype, gender, and diet together explain only from 1.4% to 15.5% of the variance in serum lipids and apolipoproteins, suggesting that other, presumably genetic, factors are major determinants.