Distinct Cellular Calcium Metabolism in Radiation-sensitive RKO Human Colorectal Cancer Cells

Radiation therapy for variety of human solid tumors utilizes mechanism of cell death after DNA damage caused by radiation. In response to DNA damage, cytochrome c was released from mitochondria by activation of pro-apoptotic Bcl-2 family proteins, and then elicits massive Ca2+ release from the ER that lead to cell death. It was also suggested that irradiation may cause the deregulation of Ca2+ homeostasis and trigger programmed cell death and regulate death specific enzymes. Thus, in this study, we investigated how cellular Ca2+ metabolism in RKO cells, in comparison to radiation-resistant A549 cells, was altered by gamma (gamma)-irradiation. In irradiated RKO cells, Ca2+ influx via activation of NCX reverse mode was enhanced and a decline of [Ca2+]i via forward mode was accelerated. The amount of Ca2+ released from the ER in RKO cells by the activation of IP3 receptor was also enhanced by irradiation. An increase in [Ca2+]i via SOCI was enhanced in irradiated RKO cells, while that in A549 cells was depressed. These results suggest that gamma-irradiation elicits enhancement of cellular Ca2+ metabolism in radiation-sensitive RKO cells yielding programmed cell death.

Transcatheter Closure of Atrial Septal Defect Using Amplatzer Septal Occluder

BACKGROUND AND OBJECTIVES: Transcatheter occlusion (TCO) may be an alternative method for the surgical closure of a secundum atrial septal defect (ASD) below 20 mm in diameter. We performed this study in order to evaluate the safety and feasibility of an Amplatzer septal occluder for closing ASD bigger than 20 mm in diameter percutaneously. SUBJECTS AND METHODS: Thirty three of 39 patients presenting with ASD were included in this study (3 patients with a large defect over 32mm and 3 with multiple defects were excluded). The median age was 8.6 years (2.2 - 54) and median weight was 27 kg (10.7 - 85). The mean defect size was 15+/-3 mm as measured by transthoracic echocardiogram, 17+/-5 mm by transesophageal echocardiogram, and 21+/-6 (11 - 32) mm by balloon stretched diameter. The balloon stretched diameter was larger than 20 mm in 20 of 33 patients. The mean Qp/Qs was 2.3+/-0.7. The mean device size was 22+/-6 mm and the mean fluoroscopic time was 13+/-7 min. RESULTS: The device was successfully implanted in 29 of 33 patients. The 4 patients in which implantation failed showed a left disc protrusion into the right atrium. Three of these patients were treated surgically, and one underwent a successful second attempt of TCO 12 months after the first trial. Complete closure was obtained in 30 patients in follow-up. The complications encountered included;cobra-shaped deformity of the device (3), transient AV block (Wenckebach) (1), embolization of the radioopaque marker into the left atrial appendage (1), failure in the first device (1), and mild mitral regurgitation at 3 months follow-up due to device protrusion into the mitral valve (1). CONCLUSION: The Amplatzer septal occluder appears to be a promising device for TCO of ASD up to 32 mm in diameter, however, long-term follow-up in a large number of patients is warranted.

Influence of Epstin-Barr Virus Infection in Immune Thrombocytopenic Purpura in Childhood / 대한소아혈액종양학회지

PURPOSE: Acute immume thrombocytopenic purpura (ITP) is relatively common hematologic disease in children. Most acute ITP is recovered within 6 month spontaneously and the complication is rare. But 10~20% of the ITP patient became a chronic form. Infection with Epstein-Barr virus (EB virus) in developing country usually occurs during infancy and early childhood. Acute ITP associated with EB virus is likely to develop chronic ITP in current literatures. We studied the pattern of laboratory findings in long term follow up of ITP with EB virus infection. METHODS: One hundred and seventy nine patients diagnosed with ITP admitted to the division of pediatric hematology, Gachon Medical Center and Hanyang University Hospital between Mar. 1991 and Jun. 2001 were reviewed retrospectively. Serologic test for EB virus was available for 57 patients and 25 of them were follow up at least 6 months. Evidence of acute EB virus infection was defined as a positive Viral Capsid Antigen (VCA) IgM or positive Anti VCA IgG and negative Ebstein-Barr virus Nuclear Antigen (EBNA). Complete remission (CR) was defined as a recovery of platelet count of more than 100 109/L and partial remission (PR) as a recovery of platelet count of 50~100 109/L, maintained for at least 6 months. RESULTS: Sixteen out of 57 patients were associated acute EB virus infection. Of this group, 8 patients were follow up at least 6 months. Forty one of 57 with no evidence of acute EB virus infection, 17 were follow up at least 6 months. The clinical and laboratory data was not different significantly in children with and without acute EB virus infection in admission. In EB virus infection group of 6 months follow up, platelet count was significantly lower than control group in 6 months follow up (P=0.006). Five patients of 8 (63%) with acute EB virus infection had chronic ITP and 2 of 17 (12%) with no evidence of EB virus infection had chronic ITP in follow up 6 months. CONCLUSION: Patients with EB virus associated ITP tended to resolved more slowly than those without EB virus infection and also showed tendency to become chronic ITP.