Canan Turkyilmaz

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.

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.

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.

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.

Hypernatremic dehydration in the newborn period and long-term follow up.

Background: Hypernatremic dehydration due to inadequate fluid intake can be a significant problem during the neonatal period and thereafter. The objective of the present study was to evaluate the term newborn infants admitted to Gazi University Hospital neonatal intensive care unit (NICU) for hypernatremic dehydration between June 2001 and June 2003 and compare the results with those of the literature search performed via MEDLINE for infants with the same diagnosis.

Role of excitatory aminoacids in neonatal hypoglycemia

Abstract Background: In many neurological disorders, injury to neurons may be due in part to overstimulation of the receptors for the excitatory amino acids glutamate and aspartate. The same excitotoxic mechanism and high aspartate levels in experimental studies led to this study of the concentrations of glutamate and aspartate and zinc, copper, and magnesium levels in the cerebrospinal fluid (CSF) of hypoglycemic newborns.

Atrial natriuretic peptide concentrations in children with pulmonary hypertension: Correlation with hemodynamic measurements

SummaryTo define the relation between atrial natriuretic peptide (ANP) and hemodynamic parameters in children with pulmonary artery hypertension, we measured the ANP concentrations of the femoral vein, right atrium, pulmonary artery, left atrium and left ventricle, or femoral artery in 32 patients during right or left heart catheterization. There is a strong correlation among the ANP levels obtained from different locations (p<0.001), and these ANP levels are positively correlated with pulmonary arterial pressures and pulmonary resistance. Patients were divided into two groups according to their pulmonary arterial pressure. The group with pulmonary arterial systolic pressure higher than 31 mmHg had higher ANP levels than the group with pulmonary arterial systolic pressure lower than 31 mmHg. When patients were grouped according to their pulmonary resistance, ANP levels in the group with pulmonary resistance over 2 U/m2 were higher than those in the group with pulmonary resistance lower than 2 U/m2. In this study ANP levels showed a correlation with the right ventricular systolic pressure. A correlation was not seen between ANP levels and the flow ratios or the presence of shunt. The results of our study suggest that ANP should be considered an important factor in pulmonary hypertension, independent of other factors.

A rare case of severe lactic acidosis in a preterm infant: lack of thiamine during total parenteral nutrition

Abstract Total parenteral nutrition (TPN) is a revolution in neonatal intensive care unit (NICU) care, but this therapy is not without problems. A 35-week-old, 1300 g female infant was transferred to our NICU because of bilious vomiting and feeding problems. When enteral feeding was started again, a severe condition similar to the previous one developed. On the 24th day, the patient underwent surgery with a diagnosis of Hirschprung’s disease. One week before surgery, the parenteral solutions were composed without vitamins because intravenous vitamin supplements suitable for infants were not available. Thereafter, the patient suffered from severe hypoglycaemia, and sepsis started to develop, accompanied by a large anion gap and metabolic acidosis which is severe lactic acidosis refractory to massive doses of bicarbonate. The acidosis improved significantly when the patient was treated with thiamin. Although TPN is life saving in the NICU, meticulous attention must be paid while treating a patient with TPN, and all possible nutrients should be provided. In this report, a case of a preterm newborn requiring a prolonged period of TPN and complicated by serious lactic acidosis is presented and discussed.