Effect of Maturation on Endothelium-Dependent Relaxation in Pulmonary Arteries of the Newborn Rabbit

PURPOSE: This study was done to determine whether maturatin alters endothelium- dependent responses in pulmonary arteries. METHODS: Vascular rings of pulmonary arteries, with and without endothelium, taken from rabbits of 3 and 30 days of age were suspended in organ chambers filled with Krebs-Henseleit solution, bubbled with 95% O2-5% CO2 and maintained at 37degrees C. Immediately after mounting, the rings were stretched progressively until a maximal response to KCl was achieved. The rings were incubated with indomethacin and allowed to equilibrate before contraction and relaxation study. RESULTS: When the endothelium was intact in arterial rings from 3-day-old rabbits, acetylcholine (ACH) (10-6 M) relaxed preconstricted rings with histamine (5x10-6 M) (98.1 4.7% relaxation, mean SD). In rings without endothelium, KCl (10-2 to 9x10-2 M) and histamine (5x10-8 to 10-5 M) caused concentration-dependent contractions. When normalized to maximal contractions achieved to each agonist, the concentration-effect curves to KCl and histamine in rings without endothelium were similar to both ages. Rings with endothelium showed a progressive shift to the right of the concentration- effect curve to histamine. Relaxation to sodium nitroprusside were unaffected by age. In preconstricted ring, ACH (10-8 to 5x10-6 M) caused relaxations in rings with endothelium which were greater at 30-day compared to 3-day-old rabbits. CONCLUSION: These study demonstrates that endothelium-dependent relaxation increase with age, possibly due to changes in the release and/or effect of endothelium-derived relaxing factor (EDRF or nitric oxide) from pulmonary arteries during the neonatal period.

A Case of Milk Allergy with Positive Contact Challenge Test / 소아알레르기및호흡기학회지

Food allergy is a state of immunologic reaction resulting from the exposure to food or food additive. The clinical symptoms and signs varied from localized symptoms at the site of direct contact such as contact urticaria, localized gastrointestinal symptoms with nausea, pain, vomiting and diarrhea to systemic symptoms occurring in remote organs, such as skin, respiratory system, cardiovascular system. We reported a case of 8 month-old girl with milk allergy who presented skin symptoms after cutaneous contact with milk protein. Developed after 15 minutes of milk contact challenge on forearm and followed by erythematous papules and wheals distributed throughout the face and neck area accompanied by edema and itching. The symptoms were continued for 2 hours and disappeared after an injection of pheniramine maleate.

Results of Balloon Angioplasty in Patients with Coarctation of the Aorta

PURPOSE: This study was undertaken to analyze and compare the effects of percutaneous balloon angioplasty(BAP) on postoperative re-coarctation and native coarctation of the aorta(CoA) and to thereby contribute to the development of treatment methods for CoA. METHODS: The subjects in this study were 21 children who had undergone BAP from Jan. 1996 to Dec. 2000 in the Division of Yonsei Pediatric Cardiology. The relation between factors such as pressure and diameter changes across the coarctation segment together with hemodynamic and morphologic variables of children with postoperative re-coarctation and native CoA was analyzed through retrospective study of medical records. RESULTS: Among the 21 cases, 11 children showed a decreased pressure gradient across the coarctation segment of less than 20 mmHg(average : 11+/-5 mmHg) after BAP was performed. In postoperative re-coarctation, the pressure gradient across the coarctation segment significantly fell from 56+/-21(30-90) mmHg to 20+/-13(0-50) mmHg(P<0.001) after BAP, while in native CoA, the pressure gradient decreased from 57+/-13(40-70) mmHg to 22+/-14(10-40) mmHg(P<0.001) after BAP. The diameter of the narrowest coarctation segment was significantly increased in native CoA and postoperative re-coarctation after BAP. The factor that most affected our results was the ratio of isthmic/descending aortic dimension showing an inverse relationship between the ratio of isthmic/descending aortic dimension and pressure gradient after BAP(gamma=-0.473, P=0.030). Complications included one case of femoral artery stenosis, one case of femoral artery interruption, and one case in which seizure occurred two days after BAP due to cerebral thrombosis. CONCLUSION: We conclude that BAP is an effective treatment modality in postoperative re- coarctation and native CoA.