Biomedical subjects

M Pezzati

Publications and source records attributed to M Pezzati.

At least 19 recordsLinked to original sources

PubMed2004

Prediction of early tolerance to enteral feeding by measurement of superior mesenteric artery blood flow velocity: appropriate- versus small-for-gestational-age preterm infants.

AIM: To evaluate whether serial Doppler measurements of superior mesenteric artery blood flow velocity could predict early tolerance to enteral feeding in preterm infants. METHODS: In a prospective study, 54 healthy preterm neonates were assigned to one of the following groups: neonates with birthweight appropriate for gestational age (group 1), neonates small for gestational age without (group 2) and with prenatal haemodynamic disturbances (group 3). We studied Doppler blood flow velocity and resistance index before and after the first feed. RESULTS: Contrary to patients of group 3, infants in groups 1 and 2 showed a significant increase in blood flow velocity and a significant decrease in resistance index from the preprandial values after the first feed. At each postprandial time, we found significant differences in all velocity and resistance measurements between patients of group 3 and patients of both groups 1 and 2. In all patients, we found that the value of mean velocity measured 30 min after the first feed was the most predictive of early feed tolerance, with 95% sensitivity and 94% specificity when mean velocity >0.38 m/s. CONCLUSION: Small-for-gestational-age preterm infants with prenatal haemodynamic disturbances have an unusual intestinal haemodynamic response to the first feed. In the whole group of preterm infants, the value of mean velocity measured 30 min after the first feed is a good tool for the clinician in predicting early enteral feeding.

Blood Flow Velocity↗

PubMed2004

Effect of blood transfusions on oxidative stress in preterm infants.

OBJECTIVE: To confirm the increase in non-transferrin bound iron (NTBI) after packed red cell (PRC) transfusion and to evaluate the association with increased oxidative stress in preterm infants. METHOD: Twenty healthy preterm infants (gestational age 28.2 (2.2) weeks; birth weight 1047 (230) g), who required blood transfusion for anaemia of prematurity were prospectively studied. Serum concentrations of NTBI, total hydroperoxides (TH), and protein SH groups, and plasma total radical trapping antioxidant capability (TAC) were measured within three hours before and after PRC transfusion. The infants were transfused with 38.6 (23) ml PRCs over 5.8 (1.0) hours, at a mean age of 43.3 (25.1) days. RESULTS: After PRC transfusion, haemoglobin concentration increased from 9.2 (1.1) to 14.6 (1.5) g/l. Mean plasma NTBI concentration after transfusion was significantly higher (0.43 (0.45) v 2.03 (1.31) micromol/l; p = 0.001), while plasma concentrations of TH (212.3 (42.2) v 214.7 (66.3) Carr units/l) and protein SH groups (317.5 (38.8) v 353.8 (57.4) micromol/), and TAC (256.3 (36.1) v 267.1 (42.4) micromol HClO/ml) remained unchanged. CONCLUSION: For three hours after PRC transfusion, plasma NTBI is significantly increased in preterm infants, but this is not associated with significant changes in oxidative stress.

Antioxidants↗

PubMed2003

Redox status in very-low birth-weight newborns.

Inborn metabolic diseases, such as disorders in pyruvate metabolism, in gluconeogenesis or in the respiratory chain, may present with lactic acidosis in newborn infants. A simple tool to screen for the efficacy of mitochondrial oxidation reduction activity is the detection of the redox status through simultaneous measurements of plasma lactate, pyruvate and ketone bodies, which are strongly influenced by feeding and stress. We present the redox status values of 55 very-low birth-weight infants under different nutritional conditions. We were able to demonstrate that the redox status values are not dependent on the type of nutrition (oral feeding or continuous enteral nutrition). Instead we observed a strong difference between newborns with intrauterine growth retardation and newborns with appropriate growth. Newborns with intrauterine growth retardation show lower preprandial values of glucose and ketone bodies than newborns with appropriate weight, but higher levels of lactate and pyruvate; nevertheless the lactate/pyruvate and beta-hydroxybutyrate/acetoacetate ratios are normal. The results of the redox status study could suggest the reduced activity of gluconeogenesis and, probably, of beta-oxidation in very-low birth-weight newborns with intrauterine growth retardation.

3-Hydroxybutyric Acid↗

PubMed2003

Plasma bilirubin level and oxidative stress in preterm infants.

OBJECTIVE: To assess the hypothesis that changes in plasma total bilirubin levels (Btot) can influence the antioxidant system and oxidative stress in preterm infants. METHODS: Twenty two healthy preterm infants who presented with visible non-haemolytic hyperbilirubinaemia were studied at the mean (SD) age of 3.7 (1.5) days. Btot, plasma total hydroperoxide concentration (TH), plasma protein SH group concentration, and total antioxidant capacity of the plasma (TAC) were measured at study entry and after 24 hours. RESULTS: Btot did not correlate with TH, TAC, or protein SH group concentration, but a significant correlation was found between TH and TAC, TH and protein SH groups, and TAC and protein SH groups, both at study entry and after 24 hours. CONCLUSION: The decrease in plasma bilirubin was contemporary with an increase in plasma antioxidant capacity and decrease in oxidative stress in preterm infants. This may be the result of the pro-oxidant effect of haem oxygenase, mediated by iron release, which may outcompete the antioxidant properties of bilirubin.

Antioxidants↗

PubMed2003

Prolonged hyperinsulinemic hypoglycemia in a small for date preterm.

Hyperinsulinism is an important cause of hypoglycemia in early infancy. Many forms of hyperinsulinemic hypoglycemia are described: transient, prolonged, persistent. Transient forms are well recognized in infants of diabetic mother; prolonged forms are responsible for the hypoglycemia in small-for-date (SGA) infants and asphyxiated newborns. Persistent hyperinsulinemic hypoglycemia occurs in a group of congenital disorders associated with an abnormality of beta-cell regulation throughout the pancreas. Accurate diagnosis and treatment are essential in all various forms of hyperinsulinism also because newborns are at high risk of permanent brain damage. We report a case of prolonged hyperinsulinemic hypoglycemia in a SGA preterm, immediately treated with a high dose of glucose and glucocorticoid and then with diazoxide. Hypoglycemia was continued until 2 months of age when it resolved spontaneously and completely.

Glucose↗

PubMed2002

Effect of blood transfusions on cerebral haemodynamics in preterm infants.

AIM: To assess the possible cerebral haemodynamic changes occurring in preterm infants after blood transfusions. METHODS: Preterm infants who had undergone blood transfusions were prospectively studied using both near infrared spectroscopy and cerebral Doppler ultrasonography. RESULTS: Fourteen infants (mean gestational age 29.6 wk, SD 2.6; mean birthweight 1,430g, SD 332) were studied at the mean age of 29 (SD 14) d. A significant increase in oxygenated haemoglobin (O2Hb), deoxygenated haemoglobin (HHb), mixed cerebral oxygen saturation (SmO2) and change in cerebral blood volume occurred after transfusion. Between ultrasound parameters, we found a decrease in diastolic velocity and an increase in resistance index. CONCLUSION: Blood transfusions improve cerebral oxygen supply and induce a decrease in cerebral blood volume, probably due to an increase in cerebral vessel resistance.

Anemia↗

PubMed2002

Haemodynamic changes in the brain after vaginal delivery and caesarean section in healthy term infants.

OBJECTIVE: To investigate whether the mode of delivery may affect neonatal cerebral haemodynamics during the first hour of life. DESIGN: Prospective study. SAMPLE: Healthy infants with gestational age > or =37 weeks and birthweight appropriate for gestational age, born after uncomplicated pregnancy by vaginal delivery or elective caesarean section, two to five hours after the delivery. METHODS: Near infra-red spectroscopy was used to measure changes of oxygenated haemoglobin, deoxygenated haemoglobin, oxidized-reduced cytochrome aa3, and mean cerebral oxygen saturation (mixed cerebral oxygen saturation = oxygenated haemoglobin/total haemoglobin). Changes in cerebral blood volume were calculated. RESULTS: Near infra-red spectroscopy data did not show significant differences between infants born by vaginal delivery or by caesarean section. There was a significant decrease of oxygenated haemoglobin and change of cerebral blood volume values at 120 and 180 minutes in both the groups, while deoxygenated haemoglobin and oxidized-reduced cytochrome aa3 were unchanged. CONCLUSIONS: A decrease of cerebral blood volume occurs after birth and this occurs both in infants born by vaginal delivery and by caesarean section.

Blood Pressure↗

PubMed2002

Pharmacokinetics of oxatomide in preterm infants.

The pharmacokinetics and tolerability of oxatomide oral suspension were investigated in preterm infants to evaluate the feasibility of planning a further study to assess its antiinflammatory effects and its effectiveness in preventing chronic lung disease (CLD). Following the administration of oxatomide 1 mg/kg, the peak plasma concentration (Cmax), the elimination half-life (t1/2), the volume of distribution (Vd), and the area under the curve (AUC) 0-36 h were measured and the following results were obtained: 42.2 +/- 15 ng/ml at 2 h after oxatomide administration, 41.4 +/- 2.0 h, 37.4 +/- 4.2 l/kg, and 468 +/- 52 ng/ml/h, respectively. Our study, therefore, demonstrated that a dose of 1 mg/kg/day oxatomide was effective in reaching therapeutic plasma levels in preterm infants without inducing adverse effects.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2001

Randomised controlled trial of the effect of cisapride on the pyloric muscle in preterm infants.

UNLABELLED: In this study we determined the effects of cisapride on the pyloric muscle in preterm infants. To perform a randomised, double blind, placebo controlled study, two groups each of 16 preterm newborns were given either cisapride (0.2 mg/kg every 8 h) or a placebo for at least 7 days. Infants were studied first on the day when treatment with cisapride or placebo was to be initiated (time 0), and then after 3 (time 1) and 7 days (time 2). In each group, the following parameters were studied by ultrasonography: cross-sectional diameter of the entire pylorus, muscle thickness, and length of the pyloric canal. Also, the mean daily total gastric aspirate volume was studied for the entire week of the study. At time 0, we observed no significant differences between the two groups with respect to diameter, muscle thickness and length of the pyloric muscle. At time 1 and time 2, both diameter and muscle thickness were significantly greater in the cisapride group than in the placebo group. Furthermore, the length of the pyloric canal was significantly greater in the cisapride group than in placebo group at time 2, though not so at time 1. For the entire week of the study, we found a significantly larger mean daily total gastric aspirate volume in the group of infants treated with cisapride compared to the placebo treated group. CONCLUSION: Cisapride significantly affects all of the main measurements of the pyloric muscle and causes a significantly larger amount of daily total gastric aspirate volume. Its use to promote feeding intolerance in preterm newborns cannot be recommended.

Analysis of Variance↗

PubMed2001

The role of blood transfusions and iron intake on retinopathy of prematurity.

BACKGROUND: The role of blood transfusions and iron intake in the pathogenesis or retinopathy of prematurity (ROP) is controversial. AIM: To evaluate the influence of packed red cell (PRC) transfusions and iron intake on ROP incidence. STUDY DESIGN: Prospective observational study. SUBJECTS: Forty-five preterm infants with birthweight <1250 g were studied. After ophthalmological study, they were divided into group A (n=24) that included newborns without ROP, and group B (n=21) that included newborns with ROP. RESULTS: Logistic regression analysis demonstrated that gestational age (OR 0.61; 95% C.I. 0.41-0.90), transfusion volume during the first week (OR 1.16; 95% C.I. 1.03-1.3) and during the first 2 months of life (OR 2.93; 95% C.I. 1.52-5.62), and iron intake during the first week of life (OR 1.15; C.I. 1.01-1.32) and during the first 2 months of life (OR 2.93; 95% C.I. 1.52-5.62) were associated with the development of ROP. CONCLUSION: Our study showed that gestational age, blood transfusion volume and iron load by transfusions are associated with the risk of occurrence of ROP in infants with a birthweight of less than 1250 g.

Erythropoietin↗

PubMed2001

Influence of maternal magnesium sulphate and ritodrine treatment on cerebral blood flow velocity of the preterm newborn.

BACKGROUND: To evaluate the effect of antenatal tocolytic administration of magnesium sulphate and ritodrine on the cerebral blood flow velocity and on the cerebral vascular resistance of preterm newborns in the first hours of life. METHODS: Cerebral blood flow velocity, resistance index and relative vascular resistance were studied in 27 preterm infants (<34 weeks gestation) with antenatal exposure to maternal magnesium sulphate treatment and in 27 preterm infants (<34 weeks gestation) with antenatal exposure to maternal ritodrine treatment. Both antenatal magnesium sulphate or ritodrine were used for tocolysis. Cerebral blood flow was measured, using Doppler ultrasonography, in the anterior cerebral artery, in the left middle cerebral artery and in the right middle cerebral artery. RESULTS: We did not find any significant difference in the blood flow velocity, resistance index or relative vascular resistance in the three cerebral arteries between the two treatment groups. CONCLUSIONS: Our study shows that maternal antenatal administration of magnesium sulphate to delay preterm delivery, compared to antenatal administration of ritodrine, does not induce any significant differences either in cerebral blood flow velocity or in cerebral vascular resistance of preterm infants in the first hours of life.

Blood Flow Velocity↗

PubMed2001

Prevention of bilirubin encephalopathy.

Prevention of bilirubin encephalopathy is based on the detection of infants at risk of developing a significant hyperbilirubinemia. This task can be accomplished by performing a simple umbilical cord blood test, such as blood group, Rh, Coombs' test and glucose-6-phosphate dehydrogenase, in order to detect hemolytic diseases. In preterm infants, the prevention of hyperbilirubinemia with phototherapy is a relatively simple task, since these infants are cared for in hospital. Early hospital discharge of full-term neonates represents a major concern. The management of neonatal jaundice requires that therapy begins when total serum bilirubin levels are significantly below the levels at which kernicterus is considered an immediate threat. Unfortunately, determination of serum bilirubin is a painful procedure, and is not very accurate since there is a high variability in laboratory measurements. The accuracy and precision of a new transcutaneous bilirubin measurement, comparable to the standard of care laboratory test, makes the daily evaluation of transcutaneous bilirubin measurement a useful tool in distinguishing physiological from nonphysiological hyperbilirubinemia, and determining the bilirubin increment in the first days of life. Full-term neonates who lose a significant amount of weight are especially at risk of significant hyperbilirubinemia and must be treated with ad libitum feeding and intensive phototherapy.

Bilirubin↗

PubMed2000

Changes in mesenteric blood flow response to feeding: conventional versus fiber-optic phototherapy.

OBJECTIVE: To evaluate whether fiberoptic phototherapy influences the postprandial increase in mesenteric blood flow velocity similarly to conventional phototherapy in preterm infants. PATIENTS AND METHODS: With the use of Doppler color ultrasonography, blood flow velocity in the superior mesenteric artery was measured both preprandially and postprandially in 19 preterm infants during and after conventional phototherapy, and in 20 preterm infants during and after fiber-optic phototherapy. The mean arterial blood pressure/mean flow velocity ratio was calculated as an estimate of relative vascular resistance of the superior mesenteric artery. RESULTS: The study shows that conventional phototherapy blunts the postprandial mesenteric blood flow response to feeding in preterm infants. Furthermore, it shows that the postprandial increase in intestinal blood flow is not attenuated when fiber-optic phototherapy is administered, and that such postprandial increase of blood flow is significantly greater than in infants receiving conventional phototherapy. During and after fiber-optic phototherapy, a significant reduction in postprandial relative vascular resistance was found; such reduction was significantly greater than during conventional phototherapy. CONCLUSIONS: Fiber-optic phototherapy is preferable to conventional phototherapy for the treatment of hyperbilirubinemia in preterm infants because it does not affect the physiologic postprandial redistribution of blood flow from the periphery to the gastrointestinal system as does conventional phototherapy.

Blood Flow Velocity↗

PubMed1999

Effects of indomethacin and ibuprofen on mesenteric and renal blood flow in preterm infants with patent ductus arteriosus.

OBJECTIVE: To evaluate the effect of intravenous ibuprofen and indomethacin for treatment of patent ductus arteriosus (PDA) on mesenteric and renal blood flow velocity in preterm infants. STUDY DESIGN: Seventeen mechanically ventilated preterm infants (<33 weeks' gestation) with PDA received either 0.2 mg/kg indomethacin (n = 8) or 10 mg/kg ibuprofen (n = 9), infused over 15 minutes. Mesenteric and renal blood flow velocity were measured by using Doppler ultrasonography. RESULTS: Indomethacin caused a significant reduction in mesenteric and renal blood flow velocity 30 minutes after drug administration; mesenteric and renal blood flow velocity did not return to the pretreatment values by 120 minutes. Ibuprofen did not alter blood flow 30 minutes after treatment, and blood flow increased 120 minutes after treatment. Mesenteric and renal blood flow velocity changes were significantly different between the 2 treatment groups. CONCLUSIONS: Compared with indomethacin, ibuprofen did not significantly reduce mesenteric and renal blood flow velocity.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed1999

[Urinary tract ultrasonography in newborns with late oligohydramnios].

BACKGROUND AND AIM: The aim of this study was to evaluate the value of neonatal renal ultrasonography in the diagnosis of urinary tract malformation pathologies in newborns from pregnancies complicated by late oligohydramnios. METHODS: During the period January 1994-October 1997, 119 newborns from pregnancies complicated by oligohydramnios occurring in the third trimester of pregnancy underwent ultrasonography of the urinary tract at our Centre. All newborns had previously undergone prenatal ultrasonography. RESULTS: Ultrasonography revealed calicopyelic dilatation < 10 mm in 7 newborns (5.8%), 5 of whom had already been reported at the prenatal ultrasonography. One new-born (0.8%) also showed the presence of an ectopic kidney that had not been diagnosed at the prenatal scan. By the next follow-up all the calico-pyelic dilatations had become normal. CONCLUSIONS: Neonatal ultrasonography did not show any alterations to the urinary tract that might be responsible for the reduction of amniotic liquid. We therefore feel that is useful to perform neonatal ultrasonography in those situations in which the onset of oligohydramnios occurred in the second trimester of pregnancy and in cases in which no scan was performed during the prenatal period.

Female↗

PubMed1998

Renal blood flow velocity in preterm and term neonates during the fourth day of life: changes in relation to gestational age and birth weight.

Measurements of renal artery blood flow velocity have been previously reported during prenatal life and during the first month of life in neonates. Since renal flow velocity increases during the first 3 days of postnatal age we determined, during the fourth day of life, the changes of renal blood flow velocity in relation to gestational age and birth weight in 109 healthy preterm and term infants with gestational age between 26 and 42 weeks and birth weight between 750 and 3,730 g. Renal arteries were insonated about 3 mm from the abdominal aorta, by placement of a microconvex 7-MHz transducer below the costal margin in the dorsolateral area of the right or left flank. Mean flow velocity significantly increased with advancing of gestational age and birth weight. This study provides normative data for renal artery blood flow velocity in healthy preterm and term infants during the fourth day of life.

Birth Weight↗

PubMed1997

Acardiac twins. Two case reports.

The acardius syndrome is a rare complication of monozygotic twin pregnancies, occurring in 35,000 births. Development results from arterio-arterial and veno-venous anatomoses leading to predominance of one of the twins. The acardiac twin is grossly abnormal and the outcome is invariably fatal. The normal twin provides circulation for itself as well as the acardiac and the perinatal mortality is about 50-70%, as the result of congestive heart failure. Conservative therapy may be important for congestive cardiac failure in the normal twin. Surgical therapy is direct to maintain the pump fetus by interrupting the vascular communication between the twins. We present two cases of acardiac twin prenatally diagnosed by ultrasound and successfully managed by conservative therapy.

Adult↗

PubMed1994

Fetoneonatal hydrops from human parvovirus B19. Case report.

Authors report the case of a newborn who died just a few hours after the birth as a result of intrauterine Parvovirus B19 infection. Diagnosis of fetal hydrops was made by ultrasound examination at the 25th week of pregnancy. Etiology was established on the basis of specific antibody findings in the serum of the mother, the fetus (by cordocentesis), and the neonate; B19 virus was then observed in the fetus and the neonate tissues after death using the dot-blot hybridization assay and the polymerase chain reaction technique for viral DNA. The severe fetal anemia was treated with intrauterine transfusions, but achieved poor results. The pathogenesis of fetal hydrops and advisability of intrauterine treatment in such cases are discussed.

Adult↗