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Biomedical subjects

L A Ramenghi

Publications and source records attributed to L A Ramenghi.

At least 19 recordsLinked to original sources
PubMed2005

Thrombophilia and fetal germinal matrix-intraventricular hemorrhage: does it matter?

Germinal matrix-intraventricular hemorrhage (GMH-IVH) in the fetus is very rare and the role of thrombophilia in its pathogenesis is unclear. We report on the prenatal diagnosis by magnetic resonance imaging of GMH-IVH in a 24-week fetus. The newborn presented posthemorrhagic ventriculomegaly and was found to be heterozygous for two thrombophilic patterns, factor V Leiden and methylenetetrahydrofolate reductase mutation. The combination of this hypercoagulable state and prenatal GMH-IVH is discussed together with the opportunity of testing these infants for thrombophilia.

Adult↗
PubMed2003

Hydrolysed proteins in preterm formula: influence on plasma aminoacids, blood fatty acids and insulinaemia.

The data from the present investigation differ from those of the previous study. The new version of hydrolysed protein formula did not induce changes in insulinaemia or in the insulinaemia/glycaemia ratio in pre- and postprandial samples when compared with the intact protein formula. The investigation also confirmed that branch chain aminoacids regulate insulin secretion and that the length of chain is insulinotropic for fatty acids, while the degree of unsaturation is not able to reduce insulin secretion in the newborn baby. This could be caused by stimulation of insulin output activated by the C20:5 n 3; the effects of fatty acids are probably related more to the variable composition of cell membrane than to the fatty acids circulating levels.

Amino Acids↗
PubMed2003

Cerebral perfusion in infants and neonates: preliminary results obtained using dynamic susceptibility contrast enhanced magnetic resonance imaging.

BACKGROUND: Previous studies have used the dynamic susceptibility contrast enhanced (DSCE) magnetic resonance (MR) imaging technique to measure cerebral perfusion in adults. OBJECTIVE: To assess the feasibility of the technique in a heterogeneous cohort of sick human infants and identify cerebral perfusion abnormalities. METHODS: Perfusion measurements were made by characterising the changing concentration of an injected bolus of contrast agent using a series of MR images acquired during the first pass of the contrast bolus. Qualitative values of relative cerebral blood flow (rCBF) were then calculated from these data on a pixel by pixel basis to generate parametric maps of perfusion. RESULTS: Images of perfusion were successfully calculated from 12 out of 27 neonates and infants, all with established cerebral pathology. Normal vascular anatomical structures such as the circle of Willis were identified within all calculated images. Values of rCBF were generally larger in grey matter than in white matter. In several patients, perfusion abnormalities resulted in structural abnormalities which were detected in conventional MR imaging at follow up. The acquisition of perfusion data was most difficult when the least mature brains were examined because of motion artefacts and a smaller head size with a lower level of rCBF than adults. CONCLUSIONS: This preliminary study shows that: (a) maps of rCBF can be acquired from neonates and infants; (b) characterisation of the bolus passage becomes progressively easier as the brain matures; (c) early abnormalities in cerebral perfusion may have negative prognostic implications; (d) the main difficulty when using the DSCE technique to study neonates relates to image artefacts resulting from bulk head motion.

Brain↗
PubMed2002

Cerebral venous thrombosis, intraventricular haemorrhage and white matter lesions in a preterm newborn with factor V (Leiden) mutation.

We report a preterm newborn who presented extensive cerebral vein thrombosis on MRI but no abnormal neurological signs. The baby underwent MRI as germinal-matrix intraventricular haemorrhage was revealed by a routine ultrasound brain scan performed on day 16; earlier ultrasound scans (day 2, 7, 12) were all normal. Cerebral vein thrombosis was diagnosed at the first MRI scan together with abnormal restriction in diffusion weighted imaging in the frontal white matter parenchyma. Bilateral microcavitations with a linear pattern of distribution reflecting the distribution of medullary veins developed a week later in the same white matter areas where abnormal diffusion weighted imaging was formerly noted. The baby was later found to be heterozygous for factor V Leiden.

Cerebral Veins↗
PubMed2002

Magnetic resonance imaging of the infant brain: anatomical characteristics and clinical significance of punctate lesions.

OBJECTIVE: To describe the magnetic resonance imaging (MRI) characteristics of punctate brain lesions in neonates (number, appearance, distribution, and association with other brain abnormalities) and to relate them to neurodevelopmental outcome. METHODS: A retrospective analysis was performed of 110 MRI brain scans from 92 infants admitted in 1998 to the neonatal intensive care unit. Results of routine neurodevelopmental follow up (1998-2001) in those infants with punctate brain lesions were analysed. RESULTS: Punctate lesions were observed in 15/50 preterm and 2/42 term infants. In the preterm group, the number of lesions was < 3 in 20%, 3-10 in 27%, and > 10 in 53%. In 14/15 the lesions were linearly organised and located in the centrum semiovale. Other brain abnormalities were absent or minor--that is, "isolated" punctate lesions--in 8/15 and major in 7/15. In the term group, punctate lesions were organised in clusters and no other brain abnormalities were observed. Isolated punctate lesions were observed in 10/17 infants, and a normal neurodevelopmental outcome was seen in 9/10 (mean follow up 29.5 months). One infant showed a slight delay in language development. In the infants with associated brain lesions (7/17, mean follow up 27.5 months), outcome was normal in only two subjects. CONCLUSIONS: Punctate lesions are predominantly seen in preterm infants, are usually linearly organised, and border the lateral ventricles. Isolated punctate lesions may imply a good prognosis, because most of these subjects have a normal neurodevelopmental outcome so far.

Brain Diseases↗
PubMed2001

Magnetic resonance and cranial ultrasound characteristics of periventricular white matter abnormalities in newborn infants.

OBJECTIVE: To characterize the range of abnormalities within the periventricular white matter (PVWM) in a cohort of newborns using magnetic resonance (MR) brain imaging and to compare the focal MR abnormalities with the cranial ultrasound (CUS) findings. METHODS: Retrospective study of MR brain and CUS findings of infants born in the 18-month period 1998-1999. PVWM abnormalities were identified by MR and focal lesions were characterized by size, number and distribution using a grading scale. Correspondence with CUS findings was assessed. RESULTS: 175 MR examinations corresponding to n = 105 preterm infants, (median GA 28, range 23-36 weeks) and n = 25 term infants (median GA 39, range 37-42 weeks) were analysed for PVWM abnormalities. In the preterm group, MR demonstrated a normal PVWM in n = 76, focal areas of altered signal intensity (SI) in PVWM in n = 26 and venous infarction in n = 3. In the term group, MR demonstrated a normal PVWM in n = 15, focal areas of altered SI in PVWM in n = 4, oedematous PVWM in n = 2 and a middle cerebral artery infarction in n = 4. All infants with normal MR had normal CUS findings. A focal PVWM SI abnormality detectable on MR corresponded with an abnormality on CUS in only n = 10/30. CONCLUSIONS: MR appears considerably more sensitive than CUS in demonstrating the existence and extent of focal PVWM lesions in newborn infants. Satisfactory correspondence between the two imaging investigations is obtained only for cystic PVWM lesions.

Brain Ischemia↗
PubMed2001

Cerebral maturation in premature infants: quantitative assessment using MR imaging.

BACKGROUND AND PURPOSE: The assessment of whether brain development is at an appropriate level for age has become an integral part of clinical MR reporting, although few studies have quantitatively defined the developmental changes occurring in premature infants. We have developed a simple scoring system to assess four parameters of cerebral maturation--myelination, cortical folding, glial cell migration, and germinal matrix distribution--to determine the total maturation score (TMS). The aim of this study was to validate this scoring system in a large population of preterm infants across a range of gestational ages. METHODS: A retrospective analysis was conducted of MR images acquired over a 3-year period with an identical imaging protocol. Infants born more than 14 days before the imaging examination and those with a clinical or radiologic history suggestive of neuroabnormality were excluded from the study. The TMS was derived by consensus. Interobserver agreement was evaluated by using the Bland-Altman plot. RESULTS: Images from 134 infants (23-41 weeks' gestational age) were evaluated. The TMS was significantly related to the postmenstrual age of the infant, with the mean TMS for each age group increasing with advancing postmenstrual age. Interobserver agreement was found to be high (mean difference in score = 0.07, SD = 0.56). CONCLUSION: This scoring system provides a standardized method for assessing cerebral maturation in the premature infant. The TMS is easy to calculate from standard MR images, is reproducible, and can help detect changes occurring within a postnatal age of a few weeks.

Brain↗
PubMed2000

Quantitative comparison of intrabrain diffusion in adults and preterm and term neonates and infants.

OBJECTIVE: Quantitative measurements of mean water diffusivity (D(av)) were made in human neonates, infants, and adults to assess changes in brain tissue that occur with maturation. SUBJECTS AND METHODS: Values of D(av) were obtained by calculating the average of the diffusion measurements made with diffusion-sensitizing gradients placed along three orthogonal directions. The mean diffusivity, a rotationally invariant determination of apparent diffusion coefficient, was measured in five healthy prematurely born neonates and infants, in 10 healthy term neonates and infants, and in five adults. RESULTS: Values of D(av) were found to decrease with maturation in most parts of the brain. In prematurely born neonates and infants with a postmenstrual age (postgestastional age + postnatal age) under 36 weeks, the average value of D(av) in frontal white matter was 1.90 x 10(-3) mm2 sec(-1). The corresponding value was measured as 1.62 x 10(-3) mm2 sec(-1) in neonates and infants born at term with a postnatal age of no more than 43 days and 0.79 x 10(-3) mm2 sec(-1) in the adult brain. CONCLUSION: Values of D(av) are known to decrease in neonates and young infants in the period immediately after ischemic insult. This decrease and the associated increase in signal intensity seen on diffusion-weighted imaging have been used to monitor ischemic brain injury in neonates and infants. Therefore, the decrease in D(av) that occurs with maturation, which we report in this study, must be considered if quantitative diffusion measurements are used to assess ischemic neonatal brain injury.

Adult↗
PubMed1999

"Sucrose analgesia": absorptive mechanism or taste perception?

It remains unclear whether "sucrose analgesia" is related to a pre- or postabsorptive mechanism. In a double blind cross over study sucrose reduced the pain response of preterm infants exposed to heel prick blood samples only when it was administered into the mouth. It was ineffective when administered intragastrically.

Administration, Oral↗
PubMed1998

Persistently low cardiac output predicts high mortality in newborns with cardiogenic shock.

BACKGROUND: Cardiogenic shock is an acute "unstable" state of circulatory dysfunction. OBJECTIVE: To evaluate the haemodynamic aspects of 45 newborn infants affected by cardiogenic shock, in relation to etiologies and the mortality rate. DESIGN: Retrospective, correlation study of etiologies, mortality rate and haemodynamic measurements by Doppler ultrasound parameters. PATIENTS: 45 newborn infants with cardiogenic shock, Gestational Age (GA) 37 (34-41), Birth Weight (BW) 2750 (1600-3600) g and and a control group of 20 neonates [GA 38 (34-40) wks, BW 2960 (1750-3800) g]. MEASUREMENTS: Left ventricular Cardiac Output (CO) was measured by a duplex scanner with pulsed Doppler and color flow mapping echocardiography in the first 48 hours of life. RESULTS: In healthy newborns CO was 240 mL/min/kg (210-280), in newborns with cardiogenic shock CO was 170 mL/min/kg (f130-200), p < 0.01. The Stroke Volume was 1.80 mL/kg (1.70-1.90) in the control group and 1.20 (1.15-1.80) in the shocked group (p < 0.05); Heart Rate was 146 beats/min (130-160) and 160 beats/mm (140-194), (p < 0.01) respectively. Twenty-nine infants with cardiogenic shock had CO < or = 150 mL/min/kg and 5 of them (17.2%) died; 16 neonates had CO > 150 mL/min/kg and only one (6.2%) died (p < .01). Twenty-six of 36 newborns with perinatal asphyxia had CO < or = mL/min/kg and 5 of them died, while only one of 10 infants with CO > 150 mL/min/kg died. CONCLUSIONS: Our results show that persistently low CO (< or = mL/min/kg) during the first 48 hours life, in newborns with cardiogenic shock due to perinatal asphyxia is associated with a significantly higher mortality.

Cardiac Output, Low↗
PubMed1998

Magnetic resonance of the neonatal brain.

We discuss the advantages of magnetic resonance (MR) technique in the study of the neonatal brain. Major results have been obtained concerning the understanding of the normal appearance of the developing brain. Bands of cells migrating to the cortex have been identified in the frontal periventricular white matter up to late gestation. MR can also identify the disappearance of the subependymal germinal matrix with increasing gestational age. With respect to the lesions of prematurity, subependymal germinal matrix hemorrhages were for the first time identified by MR underneath the posterior horns of the lateral ventricles. Subtle ischemic lesions of the periventricular white matter, not detected by brain ultrasound scan, are also described. Analysis of the lesions of the term neonates showed the role of MR in defining a more precise prognosis of infants who have sustained "birth asphyxia". The lesions can affect the basal ganglia, watershed areas of the white matter, and cortex. MR scans performed in the second week of life seem to show a stronger association with the outcome. Brain ischemic areas of the term neonates presenting with focal or multifocal seizures can also be detected by MR. These infarcted zones are usually located in the perfusion territory of the middle cerebral artery, more often in the left hemisphere. The timing of the scan is an important factor as the conventional MR can be negative in the first two-three days after the seizures. The diffusion-weighted imaging (DWI) is a new MR technique very sensitive to acute ischemic injury, and it may solve the problem of the scan timing.

Brain↗
PubMed1998

MR features of developing periventricular white matter in preterm infants: evidence of glial cell migration.

PURPOSE: MR imaging of the brain is increasingly used in the investigation of the newborn, but little information is available on the normal appearance of the developing brain. We scanned a series of newborn infants in an attempt to define the normal appearance of developing periventricular white matter and to assess how pathologic conditions may modify this appearance. METHODS: Sixty-eight newborn infants, median postmenstrual age (PMA) 34 weeks (range, 24 to 42 weeks), were subdivided into two groups: group A (n = 33), which included those with normal clinical and sonographic examinations, and group B (n = 35), which contained those with evidence of neuroabnormality detected prior to the MR study, either clinically or by cerebral sonography. Images were acquired in two planes on a 1.5-T imager using turbo spin-echo pulse sequences. RESULTS: Symmetric periventricular bands of reduced signal intensity were noted in the frontal periventricular white matter on T2-weighted images in 98% of group A infants and in 97% of group B infants. The number of bands was inversely related to PMA. The reduction in number of bands with increasing PMA was delayed in group B infants. CONCLUSION: The uniform appearance of periventricular bands in a population of healthy infants and their relationship to the infants' maturity is consistent with the results of previous histologic studies. These studies demonstrate the presence of migrating glial cells within the periventricular white matter of infants beyond 20 weeks' gestation, when neuronal migration to the cortex is complete. We postulate that the bands seen on T2-weighted images represent groups of migrating glial cells, providing a further marker of cerebral maturation.

Brain↗
PubMed1998

Laser-Doppler-flowmetry in preterm newborns during apneic events.

MATERIALS AND METHODS: We have studied with Laser-Doppler-Flowmetry (LDF) Skin Blood Flow Perfusion (SBFP) during apneic events in 15 preterm newborns (mean GA 32.4 w; mean B.W. 1620). Eighty-four apneic episodes were analyzed and the results were gathered into two groups. Group 1 with SBFP belonging to preterms aged up to 5 days and Group 2 with SBFP records of some older newborns (from 5th to 10th day of life). At first a decrease of LDF was often observed during apneic events. RESULTS: A statistically significant difference between the two groups was noted considering the SBFP percentage reduction, the hematocrit and the time of appearance of the skin blood flow decrease. We also studied the mean of all apneic SBFP reductions in each of those newborns (11/14) who had apneic events in both periods, observing a remarkable increase in mean SBFP reduction when the newborns were older than five days. CONCLUSIONS: These differences can be caused by rheologic factors such as high hematocrit, less pronounced red cell deformability and a sort of cold vasoparalysis more evident in the first days of life. We think laser-Doppler-flowmetry be suggested when the newborn is able to better contrast the negative effects of apnea, for example centralizing the circle in favour of vital organs.

Apnea↗
PubMed1997

Hemodynamic effects of intravenous morphine infusion in ventilated preterm babies.

BACKGROUND: the importance of sedation and analgesia of newborn babies in intensive care is only now receiving recognition in many neonatal units. OBJECTIVE: to evaluate the hemodynamic effects of morphine on Cerebral Blood Flow velocities (CBFv), Cardiac Output (CO), Stroke Volume (SV), Mean Arterial Blood Pressure (MABP) and Heart Rate (HR) in ventilated preterm infants, before and during the infusion of a loading dose. DESIGN: prospective, open, non-randomized, before-after intervention study with hemodynamic measurements made by Doppler ultrasound. SETTING: neonatal Intensive Care Unit, Tertiary Care Center. PATIENTS: sequential sample of 30 ventilated preterm newborns (gestational age (GA) 29 +/- 2 wks, range 27-31, birth weight (BW) 1240 +/- 440 g, range 800-1680). INTERVENTION: each subject received an intravenous loading dose of morphine (100 mcg/Kg/h) for 2 h, followed by a continuous infusion of 25 mcg/kg/h. MEASUREMENTS: the following Doppler parameters of the anterior cerebral artery were estimated: Peak systolic flow velocity (Vs), end-diastolic flow velocity (Vd), mean flow velocity (Vm) and Pourcelot' Resistance Index (RI). Measurements of CBFv, CO and SV (by Doppler ultrasound), MABP and HR were made 30 min before (baseline values) and at 15 (M15), 30 (M30), 60 (M60) and 120 min (M120), during the morphine loading infusion. Statistical evaluation analysis of variance, significance was calculated by Student-Newman-Kenfeld test. RESULTS: there were no statistically significant changes in the cerebral and cardiac Doppler parameters before or during the 120 min of morphine loading infusion. There was a non-significant fall in MABP (MABP: Baseline value = 44 +/- 6 mmHg, M120 = 42 +/- 4 mmHg; reduction = 4%) and HR (HR = Baseline value = 148 +/- 12 beats/min., M120 = 140 +/- 16 beats/min.; reduction = 5%). CONCLUSIONS: a loading dose of morphine over 2 h did not have any significant effect on MABP or cerebral and cardiac hemodynamics. No adverse effects were noted that could be attributed to morphine therapy.

Analgesics, Opioid↗
PubMed1997

Prenatal pseudocysts of the germinal matrix in preterm infants.

Sonographic characteristics of germinal-matrix (PGM) pseudocysts of prenatal origin detected on cranial ultrasound in preterm newborns were correlated with their outcomes. PGM cysts were classified as typical or atypical, according to their location. Typical PGM cysts were present at the head of the caudate nucleus or slightly medially, adjacent to the foramen of Monro. Cysts were defined as atypical when they were located subependymally elsewhere. Only one infant of 16 with a typical PGM cyst presented with psychomotor retardation. His cerebral scan also showed subependymal calcifications due to cytomegalovirus infection. Three babies had cysts in the frontal periventricular zones (atypical PGM cyst). They had negative cranial MRI (12-15 months of age) and normal neurological follow-up (24 months). In conclusion, isolated prenatal PGM cysts in preterm infants correlate with a normal outcome.

Brain Diseases↗