Fas/FasL expression in the hippocampus of neonatal rat brains follwing hypoxic-ischemic injury / 소아과

PURPOSE: Fas is a cell surface receptor that transduces apoptotic death signals. Interaction of extracelluar domain of Fas with Fas ligand(FasL) triggers the apoptotic process in many diseases. We investigated the expression of Fas and FasL in the hippocampus of 7-day-old newborn rat brains following hypoxia-ischemia injury. METHODS: The 7-days-old newborn rats were exposed to 8 percent oxygen for two hours after the ligation of right common carotid arteries. The newborn rats were killed and their brains were removed at 12, 14 and 48 hours after hypoxic-ischemic injury. The expressions of Fas and FasL of the right hippocampus were observed by western blotting and immunofluorescent staining. RESULTS: Fas and FasL were strongly expressed in the right hippocampus ipsilateral to the ligation of the common carotid artery by western blotting at 12 hours following hypoxic-ischemic injury, and then slowly decreased. The immunofluorescent expressions of Fas and FasL strongly increased in the CA1 area of the right hippocampus at 12 and 24 hours following hypoxic-ischemic injury. The immunofluorescent expression of Fas decreased at 48 hours, but the expression of FasL persisted strongly at 48 hours following hypoxic-ischemic injury. CONCLUSION: The interaction of Fas with FasL on the cell surface may be involved in neuronal injury following hypoxic-ischemic injury in the developing brain.

Hydroxyl Radical Production after Intrastriatal Injection of Dopamine and the Effect of Growth Hormone on the Apoptosis of Striatal Neurons Injured by Hypoxia-ischemia in Newborn Rat Brain / 대한소아내분비학회지

PURPOSE:We investigated the production of oxygen hydroxyl radicals in the striatum of neonatal rat brain after intrastriatal injection of dopamine (DA) and the effect of growth hormone (GH) on the apoptosis of striatal neurons injured by hypoxia-ischemia. METHODS:The extracellular striatal levels of 2,3-dihydroxybenzoic acid (DHBA) and 2,5-DHBA as indicators of hydroxyl radical(OH-) production were measured by in vivo microdialysis in the striatums of 7 day-old newborn rats (n=10) after direct intrastriatal infusion of dopamine hydrochloride (1.0 micromol/microL). The samples of perfused artificial cerebrospinal fluid (CSF) were collected every 10 minutes interval. The levels of DA, 2,3-DHBA and 2,5-DHBA of CSF were analysed by HPLC (high performance liquid chromatography). Also, the brains were removed at 24 hour after hypoxic-ischemic injury by Rice-Vannucci method. The coronal sections (12 micrometer) of paraffin-fixed brains were stained by TUNEL (terminal transferase-mediated dUTP nick-end-labelling) technique, and the neuronal cells undergoing apoptosis in the striatum were observed by fluorescent microscopy and compared between GH-treated (50 mg/kg, Dong-Ah Pharmacy Co.) and saline-treated rats. RESULTS:The extracellualr striatal levels of 2,3-DHBA and 2,5-DHBA increased abruptly in the first 10 minutes samples after intrastriatal injection of DA. After then, the levels declined slowely. The levels of striatal extracelluar 2.3-DHBA increased up to 621.8+/-508.7% of basal levels (P<0.05), and the levels of 2.5-DHBA increased up to 262.8+/-198.1% of basal levels (P<0.05). GH reduced markedly the number of apoptotic neuronal cells in the striatum after hypoxic-ischemic brain injury. CONCLUSION: The level of hydroxyl radicals increased abruptly after intrastriatal injection of DA and GH reduced markedly the number of apoptotic neuronal cells in the striatum after hypoxic-ischemic brain injury.

Possible Neuroprotective Role of Exogenous Growth Hormone on Hypoxic-Ischemic Brain Injury in Neonatal Rats / 소아과

PURPOSE: This study was performed to evaluate the possible neuroprotective effect of exogenous growth hormone on hypoxic-ischemic brain injury in neonatal rats. METHODS: After ligation of the right common carotid artery, seven-day old Sprague-Dawley rats(n= 75) were exposed to 8% oxygen for two hours. In a growth hormone(GH)-treated group(n=25), each animal was subcutanously injected by GH(50 mg/kg, Grotrpin, Dong-Ah Pharmacy Co. KOREA) just before exposing to 8% oxygen, and then injected for the next two consecutive days by the same method. In a saline-treated group(n=25), the same amounts of saline were injected instead of GH. Other twenty five animals were sham-operated without hypoxia as a sham control group. The gross morphologic changes of extracted brains at three and seven days after injury were observed, and the ratios of wet and dry weight of each cerebral hemisphere ipsilateral and contralateral to hy poxic-ischemic injury were compared among three groups for evaluating the severity of brain edema. Also, the microscopic changes of cerebral cortex on coronal sections of paraffin-embedded brains were observed at three days after injury by light microscopy. RESULTS: The GH injection reduced the severities of gross changes at seven days after HI injury. The brain edemas of ipsilateral cerebral hemispheres to the site of ligation of the right common carotid artery were significantly decreased in GH-treated animals at three days after HI injury, compared to those in saline-treated animals(P<0.05). On light microscopic examination, neurons with pyknosis of nucleus were remarkably reduced on cerebral cortex at three days after hypoxic-ischemic injury by GH treatment. CONCLUSION: Exogenous GH might have a some neuroprotective role in hypoxic-ischemic brain injury of newborn rats.

Congenital Pulmonary Vein Stenosis Manifested by Severe Cyanosis in Infancy / 소아과

Congenital pulmonary vein stenosis(CPVS) with anatomically normal connection, a rare anomaly, usually leads to progressive pulmonary hypertension, cardiac failure in infancy, and death if untreated. Most are combined with other anomalies, particularly left to right shunt lesions. Very often, the detection of CPVS is overlooked on the initial cardiac echocardiogram, because it may be mild in its severity initially, but progresses over time. CPVS shows the turbulence at color Doppler echocardiogram and a pulsed-wave Doppler signal of >1.6 m/sec with loss of phase. We experienced a case showing a small sized secundum atrial septal defect and mild turbulence at the right pulmonary vein on the initial color Doppler echocardiogram, and at follow-up, severe cyanosis, pulmonary hypertension, right heart failure, and reopened ductus with bidirectional shunt. Complete examination of echocariogram must be warranted at the initial stage and follow-up, in order not to miss CPVS.

Survival Rate in Very Low Birth Weight Infants / 소아과

PURPOSE: We observed changes in the outcome of very low birth weight infants(VLBWI) admitted to the neonatal intensive care unit(NICU) of Dankook University Hospital(DKUH) in the last six years. METHODS: The distribution of birth weight and gestational age, survival rate, neonatal complications, and causes of death for 228 VLBWI who had been admitted to DKUH from 1st January 1997 to 31th December 2002, were observed by retrospective review of medical records. We compared the above variables between period I(1997-1999) and period II(2000-2002). RESULTS: The mean birth weight, mean gestational age, gender ratio, rate of inborn infants, and other perinatal and obstetric variables were not significantly different between the two periods, except for the rate of infants with Apgar scores less than 4 at 5 min. The survival rate of VLBWI significantly increased from period I(81.0%) to period II(85.4%)(P<0.05). Major neonatal complications of VLBWI were respiratory distress syndrome, bronchopulmonary dysplasia, retinopathy of prematurity, necrotizing enterocolitis, periventricular leukomalasia and intraventricular hemorrhage. The most common cause of death in VLBWI was pulmonary hemorrhage, and the age of death was mostly less than seven days after birth. CONCLUSION: The survival rate of VLBWI who had been admitted to the NICU of DKUH was increased without any increase in major complications, and this increase(4.4%) in survival rate was mainly from the increase in survival rate of infants with birth weights of less than 1,000 gm and gestational ages of less than 28 weeks.