Alterations of Insulin-like Growth Factor-I mRNA and IGF Binding Protein-5 mRNA Expression Following Hypoxic-Ischemic Brain Injury in Immature Rat / 대한소아내분비학회지

PURPOSE:Insulin-like growth factor-I(IGF-I) is an essential anabolic factor for postnatal rat brain development and IGF-I expression is highly abundant during the first 21 days, critical growth period. Hypoxic-ischemic brain insults occurring during the perinatal period result in neuronal necrosis and permanent brain damage. To investigate the regulation of the action of IGF-I in response to such a hypoxic insult, we examined the gene expression of IGF-I and IGFBP-5 during the first 72 hr after hypoxic-ischemic injury in immature rat brain. METHODS:Ligation of the right carotid artery of 7-day-old rats was followed by 2 hour exposure to 8% oxygen to produce severe hypoxic brain damage. Using reverse transcriptase-polymerase chain reaction(RT-PCR), the expression of IGF-I mRNA and IGFBP-5 mRNA was determined in both hypoxic and control brains at post 1, 4, 12, 24, 48 hr and 72 hr after hypoxic-ischemic insult. RESULTS:The IGF-I mRNA and IGFBP-5 mRNA expression of hypoxic brain were not different from those of controls at 1 hr of recovery but IGF-I mRNA expression was decreased rapidly at post 4 hr, this decrease more pronounced at 12 hr of recovery. IGF-I mRNA and IGFBP-5 mRNA expression were increased at 48 hr and 24 hr of recovery, respectively and both IGF-I mRNA and IGFBP-5 mRNA expression showed similar level of controls at 72 hr of recovery. CONCLUSION: Out findings suggest that IGF-I play a important role in both neuronal loss and repair process following hypoxic-ischemic brain injury and IGFBP-5 is also strongly involved in the repair of damaged brain tissue by mediating IGF-I action. (J Korean Soc Pediatr Endocrinol 2003;8:56-63)

Myeloperoxidase Assay on Hypoxic-Ischemic Brain Injury in Immature Rats / 대한소아신경학회지

PURPOSE: Neutrophils found around an infarcted area in the brain was once considered as only the physiologic response following the brain injury, but recent studies have shown that inflammatory responses by neutrophils play an important role in the reperfusion injury. The presence of polymorphonuclear leukocytes(PML) is proven by biochemical assay of myeloperoxidase(MPO) secreted in the cytoplasmic granules. We observed the process of PML infiltration on hypoxic-ischemic brain injury of immature rats by the assay of MPO activity and changes of the MPO activity after the administration of fucoidin, inhibitor of P- and L-selectin. METHODS: We used a well characterized model of the brains of 7 day-old-rats, which had unilateral hypoxic and ischemic injuries(HI). Those injuries were induced by unilateral carotid artery ligation followed by timed exposure to hypoxic inspiratory gas mixture(8% O2). MPO activity was measured in the brain tissue homogenates of HI rats(n=18) at 0, 2, 8, 24 and 48 hrs and in rats that received fucoidin immediately before and again after hypoxia(50 mg/kg, n=6) at 8 and 24 hrs. Controls(n=2) were rats with neither hypoxia nor ischemia. The brain samples were homogenized in 20 mM potassium phosphate buffer(pH 7.4) for 50 secs. The homogenate was centrifuged at 14,000 g at 4degrees C for 15 mins and the supernatant was discarded. The tissue was pulverized, weighed, and suspended in 1 mL of 50 mM potassium phosphate buffer solution(pH 6.0) containing 0.5% cetylditrimethylammonium bromide(wt/vol). The tissue was sonicated and centrifuged at 10,000 g for 15 mins. 200 micro L of the supernatant was mixed with 1 mL of 50 mM potassium phosphate buffer solution(pH 6.0) containing 10 micro L of 1.325 mM o-dianisidine hydrochloride and 170 micro L of 3% hydrogen peroxide(vol/vol). Changes in absorbance at 460 nm were measured for 5 mins by using microplate reader. One unit of MPO activity was defined as that degrading 1 micro mol peroxide/min at 25degrees C, and the result was expressed as units of MPO/100 mg tissue. RESULTS: In HI rats, MPO activity increased at 2 hrs after HI and peaked at 24 hrs in the right hemisphere. In rats with fucoidin treatment immediately before and again after hypoxia, the MPO activity significantly decreased in both hemispheres compared with HI rats(P<0.05). MPO activity in the tissue of control rats was insignificant. CONCLUSION: The dynamic changes of the MPO activity suggest the important role of PMN on hypoxic-ischemic brain injuries in immature rats. MPO activity could be used as an index of the severity of injuries of hypoxic-ischemic brains.

Evoked Potentials and Cranial Ultrasonography as a Prognostic Method in Newborn with Asphyxia

PURPOSE: This study was aimed at finding a diagnostic tool which is useful in predicting the neurologic outcome of the asphyxiated newborns. METHODS: 31 newborns with asphyxia were evaluated by brainstem evoked potentials and cranial ultrasonography(CUS). During the neonatal follow-up, we evaluated the development of the babies with Bayley Scale of Infant Development II and INFANIB on corrected age of 14 months. RESULTS: The positive prognostic value of cranial ultrasonography was 72.5% and the negative predictive value was 75.0%. Auditory evoked potential(AEP) showed poor prognostic accuracy in comparison to visual evoked potential(VEP) which showed best prognostic value(85.7%) and somatosensory evoked potential(SEP) with best negative prognostic value(81.3%). CONCLUSION: We would like to emphasize that combined modalities such as SEP snd CUS were more accurate in predicting neurologic outcomes of asphyxiated newborns than evoked potential or CUS read independently. SEP and CUS combination was useful in predicting neurologic outcome of asphyxiated newborn as well as VEP and SEP.

Radiologic Localization and Lengths of Umbilical Artery Catheter to Major Aortic Branches Determined by Ultrasonography in Neonates

PURPOSE: Incorrect positioning of umbilical artery catheter (UAC) results in an increased incidence of complications and erroneous pressure measurements. We radiologically localized major aortic branches and calculated the length of catheter from umbilicus to celiac artery, renal artery and aortic bifurcation for optimal positioning of UAC. To determine the neonatal body measurement that best predicts optimal UAC lengths, we studied three commonly used parameters-birth weight (BW), total body length (TBL) and shoulder-umbilicus length (SUL). METHODS: Fifty one high type of UAC were routinely identified by sonographic scanning from the epigastrium in longitudinal projection and 42 low type of UAC from the flank in coronal projection. The distances from the catheter tip to the celiac artery, the renal artery and to the aortic bifurcation were measured by electronic calipers and were compared with the length of the catheter from umbilicus to the tip on the chest anteroposterior radiograph. RESULTS: The celiac arteries originated from T10-T12, renal arteries Ll-L2, and aortic bifurcations L3-L5. There was positive correlation between BW, TBL or SUL and the length of catheter to the celiac artery (r2=0.476, 0.749 or 0.753), to the renal artery (r2= 0.785, 0.847 or 0.720), and to the aortic bifurcation (r2=0.714, 0.809 or 0.747). CONCLUSION: Although any one of the three parameters can be used clinically, we prefer the TBL and SUL parameters for its reliability and usefulness in emergency settings. The use of a new distribution plot of origins of major branches and regression equations for calculation of the lengths may help deciding the optimal position of UAC.

Plasma Atrial Natriuretic Peptide Concentration after Birth in Low Birth Weight Neonates

PURPOSE: Atrial natriuretic peptide(ANP) is a hormone with diuretic and natriuretic properties that is released by the atrial stretch and plays an important role in sodium and volume homeostasis. We studied plasma ANP concentration and the influence of ANP on sodium balance after birth in low birth weight neonates on the basis of 34 wks gestational age when the nephrogenesis was completed. METHODS: Twenty low birth weight neonates without congenital heart disease, respiratory insufficiency, renal disease or sepsis born between June 1997 and December 1997 at Korea University Guro Hospital were enrolled in this study. Blood sampling for ANP was done at 6 hr, 12 hr, 24 hr, 3 days, 4 days and 10 days after birth. FENa was calculated by blood and urine electrolyte and creatinine. We analyzed the correlation of plasma ANP concentration and fractional Na excretion rate(FENa). RESULTS: Plasma ANP concentration of low birth weight neonates less than 34 wks was 63.67+/-12.94pg/ml at 6 hr after birth and peaked at 24 hr(110.67+/-6.34pg/ml). Thereafter, it gradually decreased and reached 42.43+/-21.89pg/ml at 10 days(P<0.05). Plasma ANP concentration of low birth weight neonates more than 34 wks was 25.50+/-8.22pg/ml at 6 hr after birth and peaked at 12hours(152.67+/-39.93pg/ml). Thereafter, it gradually decreased and reached 42.78+/-17.67pg/ml at 10 days(P<0.001). And plasma ANP concentration did not correlate significantly with FENa in low birth weight neonates less than 34 wks(r=0.02, P=0.09), but there was good correlation between plasma ANP and FENa in low birth weight neonates more than 34 wks(r=0.6, P<0.001). CONCLUSION: From the above results, it is concluded that ANP influences renal Na excretion after 34-week gestational age when the development of distal tubule, containing ANP receptors, is rapid and contributes to body fluid and Na homeostasis.

Plasma Atrial Natriuretic Peptide and Hemodynamic Change of Patent Ductus Arteriosus in Healthy Low Birth Weight Infants without Clinical Evidence of PDA

PURPOSE: Atrial natriuretic peptide(ANP) is a hormone with strong vasodilating, diu-retic and natriuretic properties. The aim of this study was to clarify the interrelationship of ANP secretion and hemodynamic changes of patent ductus arteriosus(PDA) in healthy preterm and fullterm infants without clinical evidence of PDA. METHODS: Thirteen preterm infants and six full term infants who did not develop clinical evidence of PDA were studied at 6 hr, 12 hr, 24 hr, 3rd day and 4th day after birth, until their PDAs closed spontaneously. Plasma ANP concentrations and the hemodynamic changes of PDA were rneasured. RESULTS: The ANP concentrations of all infants increased from 34.1+/-10.9 pg/ml at 6 hr to 120.5+/-18.8 pg/ml at 12 hr, and declined thereafter gradually to 74.2+/-12.7 pg/ml at 4th day. The ANP concentrations, LA/Ao ratio and LAV decreased after ductal closure. The pulmonary flow velocity(PFV) of PDA correlated with ANP concentration in preterm infants(r=0.23, P<0.05). LA/Ao ratio correlated with ANP contration in all infants (r=0.28, P<0.05), especially in preterm infants(r=0.46, P<0.01 during 12 hr and 4th day after birth. LAV correlated with the ANP concentrations in preterm infants during 12 hr and 4th day after birth(r=0.34, P<0.05). CONCLUSION: The changes of ANP concentrations are probably due to the changes of the left-to-right shunt of PDA with left atrial stretch. Reduction of the ANP concentrations may serve as an indicator of spontaneous closure of PDA. Therefore ANP measurement may be useful in deciding the need and the timing of medical and surgical managernent of newbom infants without clinical evidence of PDA.

A Study of the Comparison of Uitrasonography with Radiography to Localize the Umbilical Venous Catheter in the Neonate

PURPOSE: Incorrect umbilical venous catheter(UVC) position results in an increased incidence of complications and rnisleading pressure measurements. Most modern catheters are radiopaque and are easily seen on plain film radiographs but the exact relation of the catheter tip to vascular anatomic landmarks is not available. We assessed the ability of ultrasonography to locate the tip of UVC. And we described the relationship between the locations of the tip of UVC on the ultrasonography and the anatomical landmark seen on the radiography. METHODS: From February 1997 to June 1997, 40 newborns admitted to NICU at Guro Hospital, Korea University, and required UVC insertion for clinical care. UVC position was checked by anteroposterior and cross table lateral radiography. And then ultrasonographic assessment was performed using Hewlett Packard Sonos-1000(Hewlett Packard, UK) with a 5 MHz transducer. The ultrasonographic examinations were documented on hard copy and compared with current plain film radiographs. The sensitivity, specificity, positive predictive value, negative predictive value for the radiography as a test to detect properly positioned UVC were calculated. RESULTS: 1) In 23 of 40 newborns the UVCs were properly positioned by anteroposterior radiography (T8-T10), but ultrasonographic examination showed that 3 UVCs were malpositioned(false positive value 13%). Detection of properly located UVC by anteroposterior radiography had a sensitivity of 76.9%, specificity of 78.6%, positive predictive value of 87% and negative predictive value of 64.7%. 2) In 13 of 40 newborns the UVCs were properly positioned by anteroposterior radiography (T8- T9), ultrasonographic examination showed that all UVCs were positioned in RA and IVC(false positive value 0%). Detection of properly located UVC by anteroposterior radiography had a sensitivity of 50%, specificity of 100%, positive predictive value of 100% and negative predictive value of 51.9%. 3) In 18 of 40 newborns the UVCs were properly positioned by cross table lateral radio- graphy(less than 7mm between diaphragm and tip of UVC), but ultrasonographic examination showed that all UVCs were positioned in RA and IVC(false positive value 10.5%). Detection of properly located UVC by cross table lateral radiography had a sensitivity of 69.2%, specificity of 100%, positive predictive value of 100%, negative predictive value of 63.6%. CONCLUSION: Ultrasonographic catheter localization is a noninvasive technique that uses no ionizing radiation and has no known deterimental side effects, and allows direct visualization of the pertinent vascular anatomy and provides more information than traditional radiography. Use of ultrasonographic guidance at the time of UVC insertion allows the catheter position to be immediately adjusted, with confirmation of the amended position, obviating the need for repeated radiological evaluations. When ultrasonography is unavailable, proper placement of UVC can be estimated by use of radiography to position the tip of UVC between the eighth and ninth thoracic vertebral body by anteroposterior radiography and less than 7mm above or below the diaphragm by cross table lateral radiography.

Study of a Comparison of Ultrasonography with Radiography to Localize the Umbilical Arterial Catheter

PURPOSE: This study was performed to observe the utilization of ultrasonography in locating the position of UAC and to compare the position with anatomical landmarks seen on radiography. METHODS: Optimal position is when the catheter tip is located between T6-T10 or L3-L5 by anteroposterior radiography (AP-R) and above the diaphragm by cross-table lateral radiography (CTL-R). Ultrasonographic studies used a Hewlett Packard Sonos 1000 with 5 MHz scanner, the distance from the catheter tip to the origin of the celiac artery in high position and the distance from the catheter tip to the origin of the renal arteries and to the aortic bifurcation in low position were measured. RESULTS: In 23 of 36 newborns, high type UAC was properly positioned by AP-R, but ultrasonographic examination showed that 3 UAC were malpositioned under 5mm above the origin of the celiac artery. Detection of properly positioned UAC by AP-R had a sensitivity of 80% and specificity of 72.7%. In 19 of 28 newborns, high type UAC was properly positioned by CTL-R, but ultrasonographic examination showed that 2 UAC were malpositioned under 5mm above the origin of the celiac artery. Detection of properly positioned UAC by CTL-R had a sensitivity of 81% and specificity of 71.4%. In 15 of 20 newborns, low type UAC was properly positioned by AP-R, and ultrasonographic examination showed that 1 UAC was malpositioned below the aortic bifurcation. Detection of properly localized UAC by AP-R had a sensitivity of 77.8% and specificity of 50%. CONCLUSION: Ultrasonographic catheter localization is a noninvasive technique that uses no ionizing radiation and has no known deterimental side effects, and allows direct visualization of the pertinent vascular anatomy, providing more information than traditional radiography.