Genetic and Environmental Influences on Retinopathy of Prematurity.

OBJECTIVE: The goals were to isolate and study the genetic susceptibility to retinopathy of prematurity (ROP), as well as the gene-environment interaction established in this disease. METHODS: A retrospective study (2000-2014) was performed about the heritability of retinopathy of prematurity in 257 infants who were born at a gestational age of ≤ 32 weeks. The ROP was studied and treated by a single pediatric ophthalmologist. A binary logistic regression analysis was completed between the presence or absence of ROP and the predictor variables. RESULTS: Data obtained from 38 monozygotic twins, 66 dizygotic twins, and 153 of simple birth were analyzed. The clinical features of the cohorts of monozygotic and dizygotic twins were not significantly different. Genetic factors represented 72.8% of the variability in the stage of ROP, environmental factors 23.08%, and random factors 4.12%. The environmental variables representing the highest risk of ROP were the number of days of tracheal intubation (p < 0.001), postnatal weight gain (p = 0.001), and development of sepsis (p = 0.0014). CONCLUSION: The heritability of ROP was found to be 0.73. The environmental factors regulate and modify the expression of the genetic code.

Grupo de Nutrición y Metabolismo Neonatal, Sociedad Española de Neonatología: recomendaciones y evidencias para la suplementación dietética con probióticos en recién nacidos de muy bajo peso al nacer / Nutrition and Metabolism Group of the Spanish Neonatology Society: Recommendations and evidence for dietary supplementation with probiotics in very low birth weight infants

Las guías de práctica clínica son una importante herramienta para la mejora de la atención sanitaria. En los últimos años, se han ido acumulando evidencias sobre el impacto de la suplementación nutricional con probióticos en el recién nacido de muy bajo peso, sin que exista uniformidad en los microorganismos y las cepas utilizadas. Desde la Sociedad Espa˜nola de Neonatología, a través de su Grupo de Nutrición y Metabolismo de SENeo, se ha acometido la elaboración de unas recomendaciones que sean útiles para orientar al neonatólogo en este campo

Clinical practice guidelines are an important tool for improving healthcare. In recent years there has been accumulating evidence on the impact of nutritional supplementation with probiotics in the very low birth weight infants. With no uniformity in microorganisms and strains Clinical practice guidelines are an important tool for improving healthcare. In recent years there has been accumulating evidence on the impact of nutritional supplementation with probiotics in the very low birth weight infants. With no uniformity in microorganisms and strains

[Nutrition and Metabolism Group of the Spanish Neonatology Society: recommendations and evidence for dietary supplementation with probiotics in very low birth weight infants]. / Grupo de Nutrición y Metabolismo Neonatal, Sociedad Española de Neonatología: recomendaciones y evidencias para la suplementación dietética con probióticos en recién nacidos de muy bajo peso al nacer.

Clinical practice guidelines are an important tool for improving healthcare. In recent years there has been accumulating evidence on the impact of nutritional supplementation with probiotics in the very low birth weight infants. With no uniformity in microorganisms and strains used. The Spanish Neonatology Society (SENeo), through its Nutrition and Metabolism Group has undertaken to develop recommendations that will be useful as a guide for the neonatologist in this field.

Problemas de salud prevalentes en los menores en centros de acogida / Prevalent health problems of children in residential care centers

Introducción: La población infantil sujeta a medidas de protección es una franja de población vulnerable, no sólo desde el punto de vista social, sino también sanitario. La principal limitación detectada en la bibliografía recientemente revisada es la escasez de estudios que evalúen la situación sanitaria de los menores durante su estancia en el sistema de protección. Nos proponemos analizar el estado de salud de una población en programa residencial básico, atendiendo a las diferencias entre grupos etarios, así como la asociación de distintas variables con el tiempo de institucionalización. Material y métodos: Se diseña un estudio transversal, realizándose dos visitas a los 26 centros de la provincia de Granada (entre diciembre de 2006 y marzo de 2007). En la primera se revisan los expedientes de los menores y en la segunda se procede a su valoración clínica. En cuanto al estudio estadístico, la muestra se distribuye en tres grupos de edad (0-5, 6-12 y 13-18 años), y se realiza el análisis comparativo y la inferencia estadística mediante las pruebas de la chi2, Kruskal-Wallis y Mann-Whitney. Resultados: Se revisa un total de 294 menores. La prevalencia global de desnutrición es del 4%, más frecuente en el grupo de 0-5 años, y la de sobrepeso del 18%, más habitual en el grupo de 6-12 años. Las alteraciones más frecuentemente detectadas son otorrinolaringológicas (ORL) (63,9%), dermatológicas (34,9%) –más prevalentes en los menores de 12 años– y conductuales (28,1%), más frecuentes en los mayores de 6 años. El seguimiento en consultas especializadas fue del 40%. En cuanto al tiempo de estancia en la institución, se observaron mayores estancias en los menores con un diagnóstico psicopatológico y con un mayor número de seguimientos en las consultas especializadas (AU)

Conclusiones: El estado de salud de los menores institucionalizados se podría considerar adecuado en líneas generales. Las principales diferencias con la población general derivan de la existencia de tasas de desnutrición algo superiores en los menores de 0-5 años y una alta prevalencia de patología ORL, dermatológica, mental y conductual. Cabe destacar la vulnerabilidad del grupo de niños de 6-12 años con un número más elevado de necesidades sanitarias (AU)

Introduction: Children under protection measures constitute a vulnerable population from both social and health standpoints. The main limitation detected in a review of the recent literature is the scarcity of studies on the health status of minors during their stay in the protection system. We proposed to study the health status of a population in a basic residential care program, investigating differences among age groups and analyzing the association of different variables with time of institutionalization. Methods: A cross-sectional study was designed that involv­ed two visits to the centres: the first to review the records of the minors and the second to carry out physical examinations. For the statistical study, the sample was divided into three age groups (0-5, 6-12 and 13-18 yrs) and the chi2, Kruskal-Wallis and Mann-Whitney tests were used for comparative analyses and statistical significances. Results: We revised 294 children. Prevalence of global malnutrition was 4%, highest in the 0-5-yr group; prevalence of overweight was 18%, highest in the 6-12-yr group. The most frequent disorders were: ENT (63.9%); dermatological (34.9%), most prevalent in children <12 yrs; and behavioural (28.1%), most prevalent in children >6 yrs old; 40% were under specialist follow-up. Longer stays in the institution were associated with a psychopathological diagnosis and higher frequency of specialist follow-up. Conclusions: The health status of institutionalised minors can in general be considered adequate. The main differences with the general population derive from the presence of somewhat higher malnutrition rates in the 0 to 5-year-olds and an elevated prevalence of ENT, dermatological, psychological and behavioural pathologies. We highlight the vulnerability of 6 to 12-year-olds, who have a larger number of healthcare needs (AU)

Melatonin increases following convulsive seizures may be related to its anticonvulsant properties at physiological concentrations.

Melatonin ( N-acetyl-5-methoxytryptamine, aMT) is an indoleamine produced by several organs and tissues including the pineal gland. Melatonin (aMT) modulates the activity of the brain, mainly acting on both GABA and glutamate receptors. Previous studies have shown the participation of melatonin in the control of convulsive crises, suggesting that aMT concentration increases during seizures, and that patients with seizures of diverse origins show an alteration of the aMT rhythm. However, what is not known is the duration of the aMT response to seizures, and whether aMT changes during seizures could be a marker of the disease. For this reason, the serum levels of aMT in 54 children with a convulsive crisis, febrile and epileptic, were analyzed during the crisis, as well as at 1 h and 24 hours after the seizure. The results show that aMT significantly increases during the seizure (Day group, 75.64+/-45.91 and Night group, 90.69+/-51.85 pg/mL), with normal values being recovered 1 h later (Day group, 26.33+/-10.15 and Night group, 27.78+/-7.82 pg/mL) and maintained for up to 24 hours, when the circadian variation of aMT returns to the normal acrophase. Due to the interindividual variation of aMT levels among healthy people, a single determination of the indoleamine concentration is not a suitable marker of the existence of a convulsive crisis unless the circadian profile of aMT secretion in the patient is known. The results obtained also support the view that the stimulation of aMT production by the convulsive crisis may participate in the response of the organism against the seizures.

Longitudinal study of the simultaneous secretion of melatonin and leptin during normal puberty.

BACKGROUND/AIMS: Pubertal changes are a consequence of the activation of the hypothalamic-pituitary-gonadal axis due to an increase in the frequency and magnitude of pulses of gonadotropin-releasing hormone (GnRH), which may depend on the intrinsic properties of the neurons of the hypothalamic arcuatus nucleus, or on the influence of neurotransmitters and/or neuromodulators. We evaluated the serum concentrations of melatonin and leptin in healthy prepubertal and adolescent subjects of both sexes, to define their participation at the initial stages and during the progression of pubertal development. METHODS: 80 pediatric subjects (47 females and 33 males), aged 6-18 years, were divided into 2 groups, prepubertal (n = 25) and adolescent (n = 55), according to the absence or presence, respectively, of physical signs of pubertal development. The subjects were assessed on two occasions: at the time of their inclusion in the study, and 12-18 months later when the subject had advanced one pubertal stage according to the Tanner classification. Blood was obtained in fasting for clinical purposes and for the hormonal study. Melatonin and leptin were measured by radioimmunoanalysis. RESULTS: As described previously, melatonin decreases at the onset of puberty and during pubertal development. Both the absolute melatonin value and the decrease between evaluations tended to be greater in females; the variations were correlated with neither an increase in body weight nor with the degree of pubertal development. The concentration of leptin increased in both sexes with the progression of puberty, this value being 40% greater in women, and correlated with the indicators of an increase in body volume and fat accumulation. Although its concentration remained stable between evaluations for both sexes, among the males the association between leptin and pubertal development took place at the start of the process, while for the females we observed a significant overall association between pubertal stage and leptin concentration, this association being stronger at more advanced Tanner stages. Neither at the onset of puberty nor during its course did we observe any significant relation between melatonin concentration and any of the Tanner stages, whether for males or for females. Neither was there any correlation between the absolute values or rates of modification of melatonin and leptin. CONCLUSION: According to the evolutionary dynamics of their respective concentrations, both initially and during pubertal progress, melatonin and leptin do not interact in the initiation or progression of human pubertal development, and do not seem to play a key role in this process.

Consideraciones sobre el manejo clínico de la diarrea aguda y la deshidratación en pediatría / Management of acute diarrhoea in Pediatrics

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Pubertad y melatonina / Puberty and melatonin

Antecedentes: La melatonina, principal producto hormonal de la glándula pineal tiene una producción nocturna máxima. Aun cuando no todos los investigadores están de acuerdo, numerosos datos sugieren que los niveles elevados prepuberales mantienen el eje hipotálamo-hipófiso-gonadal en reposo, ejerciéndose de este modo un efecto inhibidor del desarrollo puberal. Como consecuencia, el descenso de los valores séricos de melatonina con la edad activa la secreción pulsátil de hormona liberadora de gonadotropina (GnRH) y de esta forma el eje reproductor, y en consecuencia se produce el comienzo de la pubertad. Objetivo. Estudiar el patrón de excreción urinaria de melatonina en niños de distintas edades, las características de su eliminación rítmica y analizar si la pubertad se asocia a una disminución significativa de su producción. Material y métodos: Se estudiaron 32 niños (17 varones y 15 mujeres), realizándose determinaciones urinarias (mediante radioinmunoanálisis [RIA]) de melatonina en orina diurna (recogida entre las 9:00 y 21:00 h) y nocturna (recogida entre las 21:00 y 9:00 h del día siguiente) y determinaciones sanguíneas de hormona luteinizante (LH), foliculoestimulante (FSH), testosterona, estradiol y sulfato de deshidroepiandrosterona (DHEAS). Se estudia el patrón circadiano y la secreción de melatonina en los distintos estadios de Tanner de desarrollo puberal (análisis de varianza [ANOVA]). Resultados: No hay diferencias significativas entre la secreción diurna y nocturna de melatonina entre varones (1,38 0,52 pg/ ml melatonina diurna y 6,92 2,06 pg/ml melatonina nocturna) y mujeres (1,15 0,43 pg/ml melatonina diurna y 11,41 4,32 pg/ml melatonina nocturna). Hay diferencias altamente significativas (p < 0,001) entre las tasas diurnas y nocturnas de secreción de melatonina en ambos sexos. Hay diferencias altamente significativas (p < 0,001) en la secreción diurna, nocturna y total entre los distintos estadios de Tanner de desarrollo puberal, encontrándose en las comparaciones entre grupos que entre los estadios I y II, tanto en varones como en mujeres se observa un significativo descenso de estas tasas de secreción. Hay una significativa disminución de la secreción de melatonina con la edad en ambos sexos (relación lineal), con mayor descenso nocturno. No hay relación entre la secreción de melatonina y la de estradiol, testosterona, LH, FSH y DHEAS. Conclusiones: La secreción de melatonina sigue un patrón circadiano, con mayor secreción nocturna, siendo la amplitud de este ritmo significativamente superior en niñas, por mayor secreción nocturna. Se observa un descenso significativo de la secreción entre los estadios I y II de desarrollo puberal, con descenso mantenido posterior en los siguientes estadios. (AU)

[Puberty and melatonin]. / Pubertad y melatonina.

BACKGROUND: Melatonin is the main hormone secreted by the pineal gland and secretion is maximal at night. Although researchers disagree, numerous data suggest that elevated melatonin levels during the prepubertal age maintain the hypothalamic-pituitary-gonadal axis in quiescence, thus exerting an inhibitory effect on pubertal development. The decrease in serum melatonin with advancing age activates hypothalamic pulsatile secretion of gonadotropin-releasing hormone and consequently the reproductive axis, which results in the onset of puberty. OBJECTIVE: To evaluate urinary melatonin levels in children of different ages and the characteristics of its rhythmic excretion and to determine whether puberty is associated with a significant reduction in urinary melatonin levels. MATERIAL AND METHODS: Thirty-two children were studied (17 boys and 15 girls). Concentrations of 24-h urinary melatonin were quantified by radioimmunoassay in daytime samples (collected between 9.00 and 21.00) and nighttime samples (collected between 21.00 and 9.00 on the following day). Blood levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol, testosterone and dehydroepiandrosterone sulfate (DHEAS) were calculated. Circadian rhythms and melatonin secretion in the various Tanner stages were assessed (ANOVA). RESULTS: No significant differences were found between day- and nighttime secretion of melatonin among boys (daytime melatonin: 1.38 0.52 pg/ml; nighttime melatonin: 6.92 2.06 pg/ml) and girls (daytime melatonin: 1.15 0.43 pg/ml; nighttime melatonin: 11.41 4.32 pg/ml). Highly significant differences were found (p < 0.001) between the day and night rates of melatonin secretion in both genders. Highly significant differences (p < 0.001) were also found in day-, nighttime and total secretion among the different Tanner stages. Comparison among groups revealed a significant decrease in secretion rates in stages I and II in both boys and girls. Melatonin significantly decreased with age in both sexes (lineal relationship). This decrease was greater at night. No relationship was found between the secretion of melatonin and estradiol, testosterone, LH, FSH and DHEAS. CONCLUSIONS: Melatonin secretion follows a circadian pattern, with greater secretion at night. The change in this rhythm was significantly greater in girls, due to greater nighttime secretion. Secretion significantly decreases in Tanner stages I and II with subsequent decreases in the later stages.

Evaluación de la eficacia antipirética y seguridad de dos formulaciones pediátricas de ibuprofeno / Evaluation of the antipyretic safety and accuracy of two pediatric ibuprofen formulations

OBJETIVO: Comparar la eficacia y evaluar la bioequivalencia clínica de dos presentaciones de ibuprofeno para niños, suspensión y gránulos efervescentes, en el tratamiento de la fiebre. MÉTODOS: Ensayo clínico abierto, de distribución aleatoria y multicéntrico. Se administró a niños con pesos superiores a 25kg, que acudieron con temperatura axilar superior a38º C a servicios de urgencias hospitalarios, una dosis de ibuprofeno en suspensión de 7 mg/kg, o una dosis de gránulos efervescentes con la siguiente posología: 200 mg en niños con pesos entre 25 y 40 kg, o 400 mg si pesaban entre 35 y 40 kg y tenían una temperatura axilar superior a 39 ºC, así como en los niños de más de 40 kg. Se tomó la temperatura axilar antes del tratamiento y a los 30, 60, 90, 120, 180 y 240 min, y se registraron posibles efectos adversos. RESULTADOS: Se incluyeron 103 pacientes, 51 recibieron gránulos y 52 suspensión. La temperatura media se redujo en los dos grupos a lo largo del estudio (p < 0,005), sin diferencias entre ellos. Las diferencias medias de temperatura en cada momento del estudio se situó dentro del intervalo de bioequivalencia (60,5ºC). En un caso se alcanzó una temperatura axilar de 35,9 ºC, siendo el único acontecimiento adverso ocurrido. CONCLUSIÓN: Ambas formulaciones se mostraron eficaces en la reducción de la temperatura y pueden considerarse bioequivalentes clínicamente (AU)

The influence of maternal erythrocyte deformability on fetal growth, gestational age and birthweight.

The increase in blood viscosity during pregnancy reduces maternal-fetal blood flow, which can lead to fetal hypoxia and acidosis. These factors have been related to a reduction in fetal growth and to premature births. We carried out a longitudinal study of 36 normal-term gestations at different stages of the pregnancy. We analyzed the erythocyte deformability, the intraerythocyte viscosity and the plasma viscosity in the mother, as well as the relation of these parameters to fetal growth (biparietral diameter (BPD) and length of the femur), birthweight, gestational age at birth and the Agpar score. The results obtained were as follows: from weeks 25 to 36 of pregnancy (30.9 (SD 2 weeks)) there occurs a significant increase in maternal erythocyte rigidity (p < 0.05) (despite the compensatory decrease in intracellular viscosity). This increase is very significantly related to the fetal biparietral diameter (r = -0.50, p < 0.01), the length of the fetal femur (r = -0.48, p < 0.02), gestational age at birth (r = -0.73, p < 0.0001, birthweight (r = -0.63, p < 0.001) and the Agpar score 5 minutes after birth (r = 0.67, p < 0.001). Our conclusions are that the reduction in erythocyte deformability (which we attribute to alterations in the fluidity or elasticity of its membrane) and the factors that increase the aggregation capacity of the red cells (modulators of blood viscosity and of blood flow in the placental intervillous space) are risk factors for reduced fetal growth, lower birthweight and lower gestational age at birth. By avoiding maternal hematocrit levels higher than 36% we could improve uteroplacental perfusion, fetal growth and perinatal results.

Changes in erythrocytic deformability and plasma viscosity in neonatal ictericia.

We studied 45 full-term newborns divided into 3 groups. Group 1: 17 newborns with bilirubin <10 mg/dL; Group 2: 18 newborns with hemolytic ictericia (bilirubin 11-20 mg/dL) and Group 3: 10 newborns with moderate hemolytic ictericia needing exchange transfusion. The following were studied: erythrocytic deformability, plasma viscosity, plasmatic osmolarity, seric bilirubin, bilirubin/albumin ratio, free fatty acids and corpuscular volume of the erythrocytes. In full-term newborns, the following are risk factors for increased erythrocytic rigidity: neonatal hemolytic illness (p = 0.004, odds ratio: 7.02), increases in total bilirubin (p = 0.02, odds ratio: 4.3) and increases in the bilirubin/albumin ratio (p = 0.025, odds ratio: 4.25). Furthermore, the most important risk factor for high plasma viscosity is also neonatal hemolytic illness (p = 0.01, odds ratio: 2.30). The role of total bilirubin is also important (p = 0.09, odds ratio: 2.10), while that of the bilirubin/albumin ratio (p = 0.012, NS) is less so. The greater the hemolysis, the greater the erythrocytic rigidity and plasma viscosity (p < 0.01). In full-term newborns with moderate ictericia, hemolytic illness and increases in the bilirubin/albumin ratio are accompanied by rheological alterations that could affect cerebral microcirculation and cause a neurological deficit not exclusively related to the levels of bilirubin in plasma.

Relationships between methoxyindole and kynurenine pathway metabolites in plasma and urine in children suffering from febrile and epileptic seizures.

OBJECTIVE: The methoxyindole pathway metabolite, melatonin (aMT), and the kynurenine pathway metabolites, kynurenic acid (KYNA), xanturenic acid (XA) and 3-hydroxyantranilic acid (3HANA) are anticonvulsants, whereas the kynurenine pathway metabolites, L-kynurenine (KYN) and 3-hydroxykynurenine (3HK), are proconvulsants. It is thought that alterations in the concentrations of these compounds may be responsible for the excitotoxic aspect of human seizures. The aim of this study was to determine whether alterations in tryptophan metabolism might be related to the occurrence and type (febrile or non-febrile) of seizures in children. DESIGN: One hundred and eighteen children from the University of Granada Hospital were studied. They were divided into two main groups (febrile or epileptic convulsive) depending upon their clinical diagnosis. An age-, weight- and gender-matched control group was also studied. Each group was then divided into two subgroups of patients sampled between 0900 h and 2100 h (diurnal groups) and patients sampled between 2100 h and 0900 h (nocturnal groups). MEASUREMENTS: Plasma melatonin was measured in samples obtained from both the diurnal and nocturnal groups. Urinary excretion of melatonin and kynurenine metabolities were measured in an aliquot of 12-h urine samples collected from both the diurnal and nocturnal groups. RESULTS: Besides the typical circadian rhythm of melatonin we also found diurnal/nocturnal differences in the concentrations of all the kynurenines, which reached significantly higher levels during the day. In normal humans the production of methoxyindoles is lower during the day and rises at night, whereas the production of kynurenines is higher during the day and decreases at night. In patients suffering from febrile and epileptic convulsions, however, there was a significant increase in the nocturnal production of KYN, 3HK, KYNA and XA. Thus we found the circadian rhythm of kynurenines to be altered in convulsive patients. Furthermore, while the various kynurenine metabolites increased by the same amount during the night in febrile convulsive children, in epileptic children the increase in KYN and 3HK was significantly lower than the increase in KYNA and XA. During the day the proconvulsant KYN decreased significantly and the anticonvulsant XA increased in both convulsive groups. Moreover, plasma aMT increased during the day in febrile convulsive group and also during the night in both febrile and epileptic groups although showing no significant change in their urinary excretion levels. CONCLUSIONS: Our results point to the existence of an imbalance in the tryptophan metabolite pathways during convulsions, blunting the normal diurnal-nocturnal rhythm of kynurenines. They also support the idea of a difference in the production of tryptophan metabolites between febrile and epileptic patients, suggesting that the tryptophan pathways follow different routes depending upon the type and duration of the convulsion.

5-Methoxytryptophol and melatonin in children: differences due to age and sex.

It seems clear that the pineal hormone, melatonin (N-acetyl-5-methoxytryptamine), is involved in the reproductive behavior of several animal species including humans. Moreover, several data also support a role for 5-methoxytryptophol (ML), another pineal hormone, in the control of sexual processes. To test the role of ML in human reproductive axis, 128 healthy children, 68 boys and 60 girls, were studied. Each of these groups was divided in three age subgroups of 6, 11, and 14 years. A single blood sample (0900 hours) was obtained from each subject to determine melatonin, ML, FSH, LH, estradiol (girls), and testoterone (boys) by RIA. Statistical analysis of the data included ANOVA-II (factor I: age, factor II: sex) and an analysis of covariance with age as covariate. A similar plasma melatonin concentration, with a significant decrease between 6 and 11 years, was found in boys and girls. Melatonin concentrations correlate well with initiation of the pubertal development in these children, although no sex differences were found. Concentrations of ML are approximately 50% of those of melatonin. In contrast to melatonin, ML levels show significant age and sex differences. Plasma ML concentration significantly increased in boys (P < 0.001) and decreased in girls (P < 0.001) after 8 years of age. These results support the hypothesis that, besides melatonin, other pineal compounds such as ML may be involved in the maturation process in humans. The pineal indole ML may also be used as a marker of the different chronobiology in the pubertal development in boys and girls.

[Pineal functioning (melatonin levels) in healthy children of different ages. An update and the value of pineal gland study in pediatrics]. / Funcionalismo pineal (tasas de melatonina) en niños sanos de diferentes edades. Actualidad e interés del estudio de la glándula pineal en pediatría.

BACKGROUND: Classically, the function of the pineal gland involved the regulation of several endocrine and non-endocrine functions, such as seasonal breeding, biological rhythm synchronization and the sleep/wake cycle. The study of the pineal gland has not a new increasing interest due to the recent discovery that melatonin is the most potent antioxidant compound known to date. MATERIAL AND METHODS: We present here the data of aMT levels (mean +/- SD, pg/ml) measured by RIA in healthy children grouped by age and time of sample extraction. The group differences are evaluated by a mean comparison test. RESULTS: The results showed that plasma levels of aMT in cord blood reflect both the aMT levels and their circadian rhythm seen in the mother, without significant differences between umbilical artery and vein. In children between 18 months and 6 years of age, aMT concentrations at 09.00 reaches a maximum of 60.8 +/- 100.58. This value significantly decreased in children between 6-8 years old (35.54 +/- 9.17, p < 0.001), with a more significant decrease in children 8-13 years old (25.28 +/- 7.16, p < 0.01). However, in children 13-15 years of age, aMT concentrations increased to 31.14 +/- 8.29 pg/ml (p < 0.01). CONCLUSION: Our data support the existence of a functional pineal gland during the neonatal period, although it lacks the rhythmic secretion of aMT. From the preschool stage, children show a significant decrease in aMT concentration, except during the pubertal period when there is a small increase in aMT levels. In this paper we also review the available information about pineal function, specifically in regards to the relationship between pineal-melatonin and CURRENT PEDIATRICS in order to better understand the infant physiology and physiopathology related to this area.

[Changes in erythrocyte rigidity and neonatal relative viscosity during the adaptation of the newborn to extrauterine life. Observations on term and premature newborns]. / Modificaciones de la rigidez eritrocitaria y viscosidad relativa neonatal durante la adaptación del recién nacido a la vida extrauterina. Consideraciones en recién nacidos a término y pretérmino.

BACKGROUND: The deformability of the red blood cell is a important factor in the blood viscosity and it is related with the blood viscosity and it is modified by the plasma biochemical characteristics and the composition of hemoglobin in the red blood cell. In this study, we want to compare the rheologic characteristics in the blood of cord umbilical in term and preterm newborns during the first 24 hours of life and we want to evaluate that hemorheologic modifications are explained because of the different gestational age. METHODS: We studied 191 newborns in our maternity from 1989 until 1990. We analyzed four groups: In the first group (n = 40) of preterm newborn (gestational age < 37 weeks); in the second group (n = 72) of term newborns (gestational age > 37 weeks); the samples were obtained from umbilical artery immediately after the umbilical cord clamp; in the third group (n = 38) of preterm newborn and the fourth group of term newborns (n = 41) was studied during 24 hours after delivery. We analyzed the plasma viscosity, the viscosity of red blood cell (RBC) content and the RBC rigidity calculated by Taylor's coefficient. RESULTS: The RBC rigidity is greater during the post-delivery period, which could be in relation with the greater values of plasma viscosity and the RBC content during the postnatal period. The comparisons between umbilical cord of term and preterm newborn they did not show differences for the RBC content viscosity and the relative viscosity. The plasma viscosity of the umbilical cord was discretely greater in the term newborn though in meaning limits statistics. In umbilical cord the hematocrit does not defer significantly between term and preterm newborns. CONCLUSIONS: Following our data we can make firm that the RBC rigidity is increased after the delivery in term and preterm newborns and the greater relative viscosity observed in newborn to term during the first life extrauterine days in related fundamentally to the corporal liquids readjustment that occurs after of delivery.

Lipoproteins in pregnant women before and during delivery: influence on neonatal haemorheology.

AIMS: To investigate whether the lipid profile of pregnant women during parturition differs from the profile at previous stages of pregnancy and to determine the effects of maternal lipid changes on fetal or neonatal haemorheology. METHODS: Sixty pregnant women were studied, divided into two groups. Group 1 contained 30 women of mean age of 27 (SD 3) years and gestational age > 38 weeks in whom delivery had not yet begun; all these pregnancies followed an uncomplicated course and there was no evidence of any fetal pathology from previous obstetric examinations. All the women reached term and birth weight was 3340 (350) g. Group 2 contained women of mean age 26 (4) years, in whom delivery was ongoing, all of whose pregnancies reached term. The following variables were determined in all cases: total cholesterol, triglycerides, high density lipoproteins (HDL), low density lipoproteins (LDL), free fatty acids and phospholipids, and apoprotein A (apo-A) and apoprotein B (apo-B). Serum and plasma viscosity was measured with a capillary viscosimeter. RESULTS: The apo-B/apo-A and HDL/apo-A ratios increased during delivery, indicating that in pregnant women these atherogenic indices are raised during delivery compared with previous gestational stages. Significant correlation coefficients were obtained between maternal lipids (triglycerides, total cholesterol, LDL, total cholesterol/HDL, and LDL/HDL) and plasma viscosity in the neonate. CONCLUSIONS: Plasma atherogenic indices increase progressively until birth. These changes have implications for neonatal haemorheology because they cause an increase in plasma viscosity.

Pineal response after pyridoxine test in children.

To characterize the pineal response to pyridoxine, plasma melatonin was measured in one hundred and twenty children 3 hours after vitamin B6 administration. The children, aged between 1.5 and 8 years, were divided in four groups as follows: a) control day group, grouping 27 children sampled at 9:00 and at 12:00; b) control night group, grouping 29 children sampled at 21:00 and at 24:00; c) pyridoxine day group, grouping 30 children sampled at 9:00, then intravenously (i.v.) injected with 3 mg/kg of pyridoxine, and sampled at 12:00; and d) pyridoxine night group, grouping 34 children sampled at 21:00, i.v. injected with 3 mg/kg of pyridoxine, and sampled at 24:00. Melatonin concentration was measured by radioimmuno assay. The data obtained showed a significant increase in melatonin levels after pyridoxine administration in the pyridoxine night group (39.87 +/- 8.02 pg/ml basal vs 88.45 +/- 9.21 pg/ml after pyridoxine, p < 0.001). The other groups did not showed significant differences in melatonin concentrations. Statistical analysis shows that the administration of pyridoxine during the nocturnal hours represents a stimulating factor to increase the pineal production of melatonin in children.