Silvia Berni

Neonatal hyperbilirubinemia. Evidence for a role of the erythrocyte enzyme activities involved in the detoxification of oxygen radicals.

ABSTRACT. Determinations of erythrocyte enzyme scavengers of oxygen radicals (glutathione‐peroxidase, superoxide‐dismutase and catalase) and determinations of erythrocyte age‐dependent glycolytic activities (glucose‐6‐phosphatedehydrogenase, pyruvate‐kinase and glucose‐phosphate‐isomerase) were carried out in cord blood and in the blood taken on the 4th day of life in 152 newborn infants with different peak bilirubin levels. The enzyme activities scavenging oxygen radicals, glutathione‐peroxidase and superoxide‐dismutase were significantly lower in infants with peak bilirubinemia higher than 214 μmol/l, compared to less‐jaundiced neonates, both at birth and on the 4th day of life; their values correlated negatively with peak bilirubinemia at birth and on the 4th day of life. Glycolytic age‐dependent enzyme activities were significantly higher in more jaundiced newborn infants only on the 4th day of life, when their values correlated positively with peak bilirubinemia. The results of this investigation suggest that a deficiency of factors protecting from oxygen toxicity, may play a role in the development of neonatal hemolysis and jaundice.

ANTIOXIDANT ERYTHROCYTE ENZYME ACTIVITIES DURING ORAL CONTRACEPTION

Nineteen healthy young women, non-smokers and of normal weight, used a combined oral contraceptive, consisting of 20 micrograms ethinylestradiol and 150 micrograms desogestrel, for 9 cycles and were investigated before starting oral contraceptive use, and during the 3rd, 6th and 9th cycle. In all cases, the antioxidant erythrocyte enzyme activities, superoxide-dismutase (SOD), catalase (CAT) and glutathione-peroxidase (GSH-Px), were determined. Pyruvate-kinase (PK) activity was also considered as a predictable index of the age and constancy of the erythrocyte population. A steady, significant increase in GSH-Px and CAT enzyme activities was found. No significant variations were found in SOD and PK enzyme levels. These findings clearly suggest that the use of combined oral contraceptives leads to an increase in antioxidant defenses. The specific physiological and biochemical mechanisms of this response merit further investigation.

Magnesium profile in autism.

The aim of the present study was to determine and compare plasma and erythrocyte concentrations of magnesium in 12 autistic children (10 boys, 2 girls), 17 children with other autistic spectrum disorders (14 boys, 3 girls), 5 girls with classic Rett syndrome, and 14 normal children (7 boys, 7 girls) of the same age. No differences in intracellular Mg were found between controls and pathological subjects; however, autistic children and children with other autistic spectrum disorders had significantly lower plasma concentrations of Mg than normal subjects (p=0.013 and p=0.02, respectively). Although our study population was small, we conclude that children with autistic spectrum disorders require special dietary management. If these cases are diagnosed at an early stage, they can be helped through diet.

Changes in Erythrocyte Properties during the First Hours of Life: Electron Spin Resonance of Reacting Sulfydryl Groups

ABSTRACT: In an attempt to clarify the mechanism by which the red cells (RBC) of newborn infants are protected against oxidative agents, electron spin resonance (ESR) assays were carried out using the nitroxide radical 4-maleimide-2,2,6,6-tetramethylpiperidinyl-1-oxyl (Mal-6), a sulfydryl-reacting agent. The ESR assays were performed in 24 samples of cord blood, 20 samples of blood from 4-day-old infants, and eight samples of 8-h-old infants. The analyses were carried out on whole blood and washed erythrocytes were resuspended in buffered saline. The same experiments were performed in 10 blood samples from healthy adults as controls. Whole blood, before and after removing the buffy coat, and cell-free plasma were also examined by ESR assay. Cell-free plasma and buffy coats proved not to be appreciably involved in the Mal-6 behavior. The data of the ESR spectroscopy demonstrated a significantly slower reaction rate in the samples of cord blood and in blood of 8-h-old infants, compared to that of 4-day-old infants and adults. No significant differences in Mal-6 behavior could be detected between cord blood and 4-day-old infant blood in the results of ESR assays performed in washed red cells. Chemical determination of RBC-reacting sulfydryl groups and the assays of glutathione also demonstrated the absence of differences between cord blood and blood of 4-day-old infants. The results of our investigation suggest that the RBC-sulfydryl-reacting groups are less involved in the detoxification of oxidative agents during the first hours of life than in the following days. This peculiarity of RBC of younger infants appears to be due, to a considerable extent, to the modulation by plasma factors of the interactions between Mal-6 and RBC-reacting sulfydryl groups. Therefore, the changes in plasma components occurring during the first hours of life appear to modify the interactions between the RBC and the oxidative agents.

Characteristics and functional properties of red cells during the first days of life

In order to evaluate postnatal red blood cell (RBC) properties and whole-blood rheology, 36 healthy full-term newborn infants were tested twice (cord blood, 4th-day blood) for whole-blood flow rate, hematocrit, hemoglobin (Hb), RBC count, mean corpuscular volume, mean corpuscular Hb and its concentration, white blood cell and platelet count, plasma fibrinogen, erythrocyte glucose-6-phosphate dehydrogenase, glutathione peroxidase (GSH-Px), glutathione reductase, catalase and superoxide dismutase. Another 38 healthy full-term newborns were tested twice for separation of erythrocytes into fractions of different density. Healthy adults were taken as control. The results showed a decreased whole-blood flow rate in blood drawn on the 4th day with respect to cord blood. A multivariate analysis with flow rate as dependent variable demonstrated a significant positive correlation with GSH-Px on the 4th day. The assays of RBC densities showed a significant increase in the first 4 days.

Epidemiologic Study of Neonatal Jaundice A Survey of Contributing Factors

Bracci, R., Buonocore, G., Garosi, G., Bruchi, S. and Berni, S. (Division of Neonatology, University of Siena, Siena, Italy). Epidemiologic study of neonatal jaundice. A survey of contributing factors. Acta Paediatr Scand Suppl 360: 87, 1989.

Basal and post-ischemic vascular compliance in children/adolescents born small for gestational age.

BackgroundIntrauterine growth restriction plays a powerful role in influencing later susceptibility to certain chronic diseases, such as hypertension. Endothelial dysfunction and arterial stiffness are early events in the development of cardiovascular diseases (CVDs). We have studied vascular compliance in small for gestational age (SGA) children/adolescents in comparison with that in appropriate for gestational age (AGA) subjects.MethodsWe monitored blood pressure, vascular resistance and compliance in 82 children–adolescents (52 SGA, 30 AGA), by means of pulse wave analysis (CR 2000 HDI) at the radial level, before and after 3 min of ischemic stress at the brachial level.ResultsIn the children/adolescents born SGA we found a significant increase in systolic and diastolic blood pressure and vascular resistance in the basal condition; the large and small vessels were stiffer. After ischemia we observed an increased vascular response in the SGA children/adolescents: there was a great diminution of systolic and diastolic blood pressure and a larger increase of the elasticity of the conduit and resistance vessels.ConclusionsThese data show that the SGA group presented some early signs of arterial wall functional disorders. More pediatric data are needed for the evaluation by non-invasive techniques of vascular function in children–adolescents at risk of CVD.

Selenium status, birth weight, and breast-feeding: Pattern in the first month

Selenium (Se) is an essential nutritional element for humans. A low Se status has been documented in formula-fed small-for-gestational age (SGA) newborns in the first month of life. The aim of the study was to compare the nutritional selenium status in adequate-for-gestational age (AGA) and in SGA newborns in the first month of life in relation to feeding type. Se status was assessed by plasma and erythrocyte concentrations, determined by pulsed Zeeman effect-atomic absorption spectrophotometry. We studied 210 newborns divided in groups according to birth weight (129 AGA, 81 SGA) and feeding type (breast milk, formula, mixed) in wk 1–4 of postnatal life. Erythrocyte Se levels are affected neither by feeding type nor by birth weight. Se plasmatic concentrations were lower in SGA than in AGA newborns. Significant differences in mean plasma concentrations were found between formula-fed and breast-fed (p=0.013) and between formula-fed and mixed-fed (p=0.006) SGA newborns. The difference was not significant in AGA neonates. Breast-fed SGA newborns consistently showed higher plasma Se concentrations than formula-fed newborns. Unless supplemented from birth, Se intake will be inadequate in bottle-fed SGA infants.

RISK FACTORS FOR ERYTHROCYTES DURING FIRST DAYS OF LIFE

In an attempt to clarify the risk factors involved in the decreased survival of the red cells of the neonate,a comparison of erythrocytes in cord blood and those in 4 day olds was performed.The following deter minations were carried out:Hb,Htc,MCV,electron spin resonance spectros-copy of nitroxide radical Mal-6,age dependent and oxygen scavenger erythrocyte enzyme activities G-6-PD,PK,GPI,GSH-Px,SOD and CAT;F and A1 Hb percentages.The findings were as follows:l)lower reduction kinetics of the specific -SH reagent Mal-6 in the cord blood.This finding suggests limited availability of reducing agent in cord blood or decreased membrane permeability there to.2)Normalization of Mal-6 kinetics after resuspending cord blood red cells in the plasma of 4 day old infants. It is evident that significant modifications of the newborns erythrocytes are induced by plasma factors.3)Increase in the mean oxygen scavenger activity GSH-Px from birth to 4th day of life.This is most likely due to the disappearance from the circulation of the red cells less resistant to oxidative stress.4)Increase in F Hb during the first 4 days of life.The results of the present investigation demonstrate that a certain number of erythrocytes viable uder intrauterine conditions,are removed from circulation after birth.

EXPERIMENTAL STUDY ON ARTERIAL COMPLIANCE AND URINARY EXCRETION OF TGF-BETA IN A GROUP OF SMALL-FOR-GESTATIONAL-AGE CHILDREN-ADOLESCENTS: PP.6.239

Background: Intrauterine Growth Restriction play a powerful role in influencing later susceptibility to certain chronic diseases. Endothelium plays a key role in the development of atherosclerosis. Endothelial dysfunction and arterial stiffness are early events in the development of cardiovascular diseases. TGF-â triggers a profibrotic response inducing the synthesis of extracellular matrix, retards its degradation, and stimulates the synthesis of integrin. To study vascular tree in small for gestational age adolescents (SGA) versus appropriate for gestational age (AGA) subjects, we monitored basal and postischemic vascular compliance in 67 adolescents; in 30 children-adolescents we studied the urinary excretion of TGF-â before and after ischemic stimulus. Methods and Results: Arterial elasticity, by pulse wave analysis was assessed in 52 SGA and in 15 AGA, at radial level, before and after an ischemic stimulus. TGF-â excretion was detected in 14 SGA and in 16 AGA (ELISA-Quantikine R&D Systems). In SGA we observed significant increase of Systolic (+7.6 mm Hg), Pulse (+2.29 mm Hg), Diastolic Blood Pressure (+4,23) and of Vascular Resistances (+151); the elasticity of large (−2.16) and small (-1.53) vessels was worse in SGA group. After ischemia we noticed a greater vasodilation: higher decrease in Systolic (-4.1 in SGA versus –2.1 in AGA), diastolic pressure (-1.57 and –1.3 in SGA and AGA) and vascular resistances (-117 in SGA and –116 in AGA); we observed a greater increase in macrovascular (+1.73 in SGA +0.4 in AGA) and microvascular elasticity (+0.82 in SGA, +0.35 in AGA). The basal urinary excretion of TGF-â increased in SGA group and doubled after ischemic stimulus versus AGA adolescents; these post-ischemic response were significant (p = 0.01). Conclusions: Our results shows that in SGA group there are some evidences of a very precocious markers of endothelial dysfunction that is associated with a raised synthesis and release of a profibrotic agent as TGF-â, that could play a pathogenetic role in the development of arterial stiffness.