Yıldız Atalay

Magnesium pre-treatment reduces neuronal apoptosis in newborn rats in hypoxia–ischemia

Hypoxic-ischemic brain damage has significant mortality and morbidity in newborns. Although the role of magnesium in neonatal hypoxic-ischemic brain injury related to N-methyl-D-aspartate receptors has been widely studied; the effects of magnesium on neuronal apoptosis have not been known exactly in hypoxia-ischemia. The aim of this study was to investigate the effects of magnesium on neuronal apoptosis in the 7-day-old rat hypoxia-ischemia model. Seven-day-old rats were administered magnesium sulfate (group 1; n=9) or saline (group 2; n=9) intraperitoneally before hypoxia-ischemia. Additionally 18 seven-day-old rats were given magnesium sulfate (group 3; n=9) or saline (group 4; n=9) after hypoxic-ischemic insult. Neuronal apoptosis was investigated by the dUDP-biotin nick end-labeling (TUNEL) method following 3-day recovery in all subjects. In evaluating TUNEL-positive cells, we firstly calculated the areas (mm(2)) of brain regions, hippocampus, striatum, cortex, in right and left hemispheres in subjects by IMAGE analysis. The numerical density was calculated as the number of cells per square millimeter by counting all TUNEL-positive cells. Afterwards, the ratio of right side numeric density to sum of right and left side numeric densities (right Apoptosis Index) was calculated for every brain region in rats receiving magnesium and compared to vehicle groups. The right Apoptosis Index of the hippocampus in magnesium pre-treated rats (mean+/-S.D.; 36.6+/-22.1) was significantly lower than vehicle (61.0+/-16.0; P<0.05); whereas right apoptosis indices were not changed by magnesium pre-treatment in striatum and cortex. Additionally, magnesium sulfate administration following hypoxic-ischemic insult also had no effect on right apoptosis indices in all three brain regions. It is concluded that magnesium might have a role in preventing neuronal apoptosis due to neonatal hypoxic-ischemic brain injury.

Cerebrospinal fluid and serum vascular endothelial growth factor and nitric oxide levels in newborns with hypoxic ischemic encephalopathy

Excitatory amino acids, cytokines and nitric oxide (NO) have been studied in the etiology and pathogenesis of hypoxic ischemic encephalopathy (HIE) of the newborn. Vascular endothelial growth factor (VEGF) is a known mediator of angiogenesis and has been shown to induce vascular proliferation and permeability via NO-mediated mechanism during hypoxia. The objective of this study was to investigate the cerebrospinal fluid and serum VEGF and NO levels in different stages of HIE and the correlation between the two mediators. Cerebrospinal fluid (CSF) and serum samples of 19 newborns with HIE and 13 controls were obtained within the first 24 h of life and kept at -70 degrees C until the time of measurement. NO levels were determined by Sievers NOA by chemiluminescence method and VEGF levels were measured by the enzyme-linked immunosorbent assay double sandwich method. The NO levels in CSF were higher than the control and mild HIE group in newborns with moderate to severe HIE, and VEGF levels in CSF were higher in the mild HIE group compared to controls but similar in the moderate to severe HIE group compared to mild HIE and control patients. There was no difference between groups with regard to serum NO or VEGF levels, and no correlation was observed between NO and VEGF levels both in CSF and serum samples. Depending on the severity of the hypoxic insult the stimulus for NO production by VEGF may have variable effects on endothelial cells which may give rise to the current results.

Neonatal resuscitation course experience in Turkey

With appropriate resuscitation, 900 000 newborns are prevented from suffering severe asphyxia each year [1]. Simple measures such as protection from hypothermia, appropriate head positioning and suctioning and recognising those who need respiratory support can make significant changes in neonatal mortality and morbidity rates. Despite the importance of neonatal resuscitation, educational programs are still not widely developed in developing countries, mostly due to limited resources, the fact that other important health problems affecting children such as respiratory tract infections and gastroenteritis are predominant and shortage of medical staff trained for neonatal resuscitation. Turkey is one of the developing countries between Asia and Europe with 1 371 000 births per year [2] with an infant mortality rate of 42.7/1000 live births, and a neonatal mortality rate of 12.5/ 1000 [3]. There are no official neonatal resuscitation education programs in Turkey yet, despite some efforts by the government. There are 46 medical faculties, six of which are located in Ankara; and Gazi University Medical School is one of them with a well established neonatal intensive care unit (NICU). A neonatal resuscitation course for health care personnel working with neonates in different hospitals in Ankara and peripheral towns, has been organised by Gazi University Hospital. The participants were given preand posttests to evaluate their basic knowledge of neonatal resuscitation together with a written critique of the efficacy and quality of the course.

Cardiac tamponade in a newborn because of umbilical venous catheterization: is correct position safe?

Cardiac tamponade is a rare but life‐threatening complication of umbilical venous catheterization in the newborn. Most complications from central venous catheters are related to incorrect position of the catheter and it is emphasized to confirm the position of the catheter tip after placement in order to avoid possible complications. We present an unusual complication of cardiac tamponade because of umbilical venous catheterization in a term newborn which is extremely rare with correct location of the catheter tip at the junction of inferior vena cava and right atrium. We suggest that correct position never guarantees uneventful catheterization in the newborn. In any infant with a central venous catheter in situ who deteriorates clinically, pericardial effusion/cardiac tamponade must be considered and appropriate action taken.

Excitatory amino acids and taurine levels in cerebrospinal fluid of hypoxic ischemic encephalopathy in newborn

The recent studies indicating the transiently enhanced expression of excitatory amino acid receptors in hypoxia vulnerable brain regions and the elevated concentration of aspartate and glutamate in cerebrospinal fluid of asphyxiated newborns strongly suggest the role of excitatory amino acids in hypoxic ischemic brain damage in the developing human brain. In this study, we compared the concentrations of glutamate, aspartate, taurine and glycine in the cerebrospinal fluid of asphyxiated infants with values of a healthy control group. The concentrations of aspartate (5.82 +/- 3.36), glutamate (1.76 +/- 1.0) and taurine (9.32 +/- 9.1) were significantly elevated in cerebrospinal fluid of asphyxiated infants (P < 0.05). When compared to the control group, the high levels of aspartate was correlated with the degrees of hypoxic-ischemic encephalopathy (HIE) and the varying outcome. The high levels of aspartate and glutamate in the asphyxiated patients adds further evidence to the role of excitotoxicity in hypoxic ischemic encephalopathy. The mental and motor development of the patients in asphyxiated group was followed for 3 years.

Use of amplitude-integrated electroencephalography (aEEG) and near infrared spectroscopy findings in neonates with asphyxia during selective head cooling

BACKGROUND Amplitude-integrated electroencephalogram (aEEG) at <6 h is the best single outcome predictor in term infants with perinatal asphyxia at normothermia. Hypothermia treatment has changed the cutoff values for outcome prediction by using time at onset of normal trace and SWC. Cerebral hemodynamics and oxygenation changes detected by near infrared spectroscopy (NIRS) during hypothermia treatment in aphyxiated neonates are not a well known issue. AIM The aim of this study was to investigate the correlations between brain monitoring (amplitude integrated EEG and NIRS) and outcome in asphyxiated full-term infants with moderate/severe hypoxic-ischemic encephalopathy before, during and after hypothermia treatment. METHOD Ten neonates were recruited for hypothermia treatment by using the cool cap entry criteria. aEEG and NIRS were applied in 10 and 8 patients, respectively with moderate and severe hypoxic-ischemic encephalopathy before, just after brain cooling and rewarming periods. Patterns and voltages of aEEG backgrounds sleep-wake cycles (SWC) and NIRS values (TOI% and FTOE) were recorded. During the follow up their outcomes were assessed by using the Bayley Scales of Infant Development II. CONCLUSION Hypothermia changes the predictive value of early aEEG. Normalization of a babys aEEG and the appearance of SWCs while being cooled occurs later. In our study one patient had normal aEEG background pattern at 80 and imminent SWC at 90 h after birth and still had normal Bayley scores at 24 months. Time to normal aEEG and SWC appearance should be carefully evaluated during the cooling period. NIRS values were different due to the clinical presentations of the patients.

Transient Neonatal hypoglycemia: Long-term effects on neurodevelopmental outcome

OBJECTIVE To investigate the frequency, etiology and consequences of neonatal hypoglycemia. STUDY DESIGN Ninety-four infants admitted to Gazi University Hospital neonatal intensive care unit for hypoglycemia (blood glucose <2.2 mmol/l 140 mg/dl]) over the past 5 years were identified and investigated with regard to cause, duration of treatment and neurological outcome. RESULTS The frequency of neonatal hypoglycemia in our unit was 94/1,023 (9.18%). Twelve infants with hypoglycemia were small for gestational age (SGA), 55 were appropriate for gestational age (AGA), and 27 were large for gestational age (LGA). The cause of the hypoglycemia was not identified in 53 infants. SGA infants required the longest duration of i.v. glucose infusion. Forty-eight patients received psychometric evaluation, one patient showed a language deficit and two patients showed motor deficits. CONCLUSION Neonatal hypoglycemia is a dangerous condition for its acute and chronic complications, and may be observed in infants with no clear risk factors. However, if acted upon early, these complications are preventable with mostly very simple measures.

Tau and S100B Proteins as Biochemical Markers of Bilirubin-Induced Neurotoxicity in Term Neonates

We investigated the relationship between total serum bilirubin and serum Tau and S100B protein levels, and predicted a cutoff level of bilirubin-induced neurotoxicity in term newborns. Total serum bilirubin, serum Tau, and S100B levels were measured in 92 jaundiced term newborns. A neurologic examination, electroencephalogram, brainstem auditory-evoked response, and otoacoustic emission were performed in the infants on admission and at age 3 months. Serum Tau (r = 0.921, P < 0.001) and S100B (r = 0.927, P < 0.001) levels were correlated with total serum bilirubin levels in all infants. Serum Tau and S100B protein levels remained at a steady level up to a total serum bilirubin level of 19.1 mg/dL, and then demonstrated a significant increase. Mean total serum bilirubin, serum Tau, and S100B levels of infants who manifested auditory neuropathy, neurologic abnormalities, or electroencephalogram abnormalities were significantly higher than in infants without these abnormalities (P < 0.05). Clinical and laboratory findings of bilirubin-induced neurotoxicity developed after a total serum bilirubin level of 22 mg/dL was reached. Serum levels of Tau and S100B proteins in jaundiced term newborns were strongly correlated with early-phase bilirubin encephalopathy.

Scrum Leptin Levels and their Relationship to Tumor Necrosis Factor« and Interleukin-6 in Neonatal Sepsis

Circulating leptin concentrations are raised in animal models of inflammation and sepsis and leptin production is also increased in rodents by administration of endotoxin or cytokines. The purpose of this study was to investigate the effect of sepsis on serum leptin concentration and whether circulating leptin was related to tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) release in newborn infants. Plasma leptin, TNF-alpha and IL-6 were measured in 20 neonates with culture-proven sepsis as soon as sepsis was diagnosed and after recovery and in 15 healthy control infants. There was no significant difference in plasma leptin levels between septic and control infants (p > 0.05); there was also no difference in plasma leptin levels in septic neonates before and after therapy (p > 0.05). No relationship between leptin and TNF-alpha (r = 0.16, p > 0.05) or IL-6 (r = 0.12, p > 0.05) was identified. These findings suggest that a major role of leptin in acute neonatal sepsis appears unlikely.

Radiation Exposure to Premature Infants in a Neonatal Intensive Care Unit in Turkey

Objective The aim of this work was to determine the radiation dose received by infants from radiographic exposure and the contribution from scatter radiation due to radiographic exposure of other infants in the same room. Materials and Methods We retrospectively evaluated the entrance skin doses (ESDs) and effective doses of 23 infants with a gestational age as low as 28 weeks. ESDs were determined from tube output measurements (ESDTO) (n = 23) and from the use of thermoluminescent dosimetry (ESDTLD) (n = 16). Scattered radiation was evaluated using a 5 cm Perspex phantom. Effective doses were estimated from ESDTO by Monte Carlo computed software and radiation risks were estimated from the effective dose. ESDTO and ESDTLD were correlated using linear regression analysis. Results The mean ESDTO for the chest and abdomen were 67 µGy and 65 µGy per procedure, respectively. The mean ESDTLD per radiograph was 70 µGy. The measured scattered radiation range at a 2 m distance from the neonatal intensive care unit (NICU) was (11-17 µGy) per radiograph. Mean effective doses were 16 and 27 µSv per procedure for the chest and abdomen, respectively. ESDTLD was well correlated with ESDTO obtained from the total chest and abdomen radiographs for each infant (R2 = 0.86). The radiation risks for childhood cancer estimated from the effective dose were 0.4 × 10-6 to 2 × 10-6 and 0.6 × 10-6 to 2.9 × 10-6 for chest and abdomen radiographs, respectively. Conclusion The results of our study show that neonates received acceptable doses from common radiological examinations. Although the contribution of scatter radiation to the neonatal dose is low, considering the sensitivity of the neonates to radiation, further protective action was performed by increasing the distance of the infants from each other.