Comprehensive analysis of microRNA-mRNA co-expression in circadian rhythm

To investigate the potential role of microRNA (miRNA) in the regulation of circadian rhythm, we performed microarray-based expression profiling study of both miRNA and mRNA in mouse liver for 48 h at 4-hour intervals. Circadian miRNA-mRNA target pair is defined as the pair both elements of which show circadian expression patterns and the sequence-based target relationship of which can be predicted. Circadian initiators, Clock and Bmal1, showed inversely correlated circadian expression patterns against their corresponding miRNAs, miR-181d and miR-191, targeting them. In contrast, circadian suppressors, Per, Cry, CKIe and Rev-erba, exhibited positively correlated circadian expression patterns to their corresponding miRNAs. Genomic location analysis revealed that intronic region showed higher abundance of cyclic than non-cyclic miRNAs targeting circadian genes while other (i.e., 3'-UTR, exon and intergenic) regions showed no difference. It is suggested that miRNAs are involved in the regulation of peripheral circadian rhythm in mouse liver by modulating Clock:Bmal1 complex. Identifying specific miRNAs and their targets that are critically involved in circadian rhythm will provide a better understanding of the regulation of circadian-clock system.

A Study on the Animal Epithelium as A Causative Allergen in Children with Asthma and Rhinitis / 소아알레르기및호흡기학회지

PURPOSE: The exposure to domestic animals has been increased, but there is no systematic evaluation for the clinical importance of animal antigens in Korea. The purpose of this study is to evaluate the significance of animal epithelial antigens as the causative allergens in childhood asthma and rhinitis. METHODS: In 228 children with asthma and rhinitis, allergic skin tests were done with 72 extracts, including 5 animal epithelial antigens. RESULTS: According to the results of allergy skin tests, 208 out of 228 children showed positive skin reactions to more than one antigens, and 128(61.4%) showed positive reactions to animal epithelial extracts. Among them, 17(8.1%) were mites non-sensitive to house dust and sensitive to animal epithelium. The positive reaction to each antigens were as follows:D. farinae(72.6%), D. pteronyssinus(69.7%), rabbit(40.3%), cat(33.1%), dog(24.0%), horse(16.8 %), and cow(14.9%). The degree of skin reactions to animal epithelial antigens were weaker than those to house dust mites. The positive concordance rates between skin tests and specific IgE reactions to D. pteronyssinus and cat/dog were 89.1%, and 25.9%, respectively. We experienced six patients with asthma and rhinitis who suspected animal epithelium as a causative allergen. CONCLUSION: Up to 61.4% of children with respiratory allergy showed positive reactions to animal epithelial extracts and 8.1% of them were house dust mites non-sensitive cases. Therefore, animal epithelium should be investigated as a causative allergen when skin reactions were strong and showed positive specific IgE antibodies.

Ischemic Stroke in Children: Analysis of Risk Factors / 대한소아신경학회지

PURPOSE: This paper evaluate and classified the risk factors that could possibly cause ischemic stroke in children, and investigate whether TOAST classification could be applied to the ischemic stroke in children. METHODS: From March 1995 to February 2002, we retrospectively reviewed the medical record of 87 patients under the age 16 who had been registered to the Ajou Stroke Registry. We evaluated the risk factors of ischemic stroke according to the Ajou Stroke Registry Protocol, and classified the risk factors into 6 main subgroups. In addition, the risk factors were investigated according to the age distribution. TOAST classification had been applied to children with ischemic stroke. RESULTS: There was 64 ischemic stroke(73.6%) and 23 hemorrhagic stroke(26.4%) among the 87 patients. In children with ischemic stroke, there was three major peak age; 13 patients younger than 1 year old(15.3%), 26 patients in age 5 to 8 years old(40.6 %), 22 patients in 9 to 12 years old(34.3%). Vasculopathy(48.6%) was the most common risk factor of the ischemic stroke in this study. Other important risk factors in order of frequency were hypertensive encephalopathy(12.5%), infectious disease(7.8%), metabolic disease(7.8%), and hematologic disease(6.2%). Moyamoya disease was the most common cause of ischemic stroke due to vasculopathy. If we analyze the risk factors according to the age at the presentation of ischemic stroke, 90% of the ischemic stroke due to vasculopathy had been developed after 5 years of age. However, ischemic stroke due to infectious disease had been developed less than 4 years of age. Major stroke was the most common subtype of the ischemic stroke in children, but TIA had been found in 80% of the patients with ischemic stroke due to moyamoya disease. TOAST classification determined the subtype of the ischemic stroke only in 2 children. Risk factors of ischemic stroke in the remained 62 patients were extremely variable, and could not be applicable to the TOAST classification. CONCLUSION: Risk factor of ischemic stroke were found in the 90% of patients. Although risk factors of ischemic stroke were extremely variable in children, cerebral vasculopathy including moyamoya disease was the most common. However, inherited metabolic disorder, coagulopathy, and hypertensive encephalopathy were also relatively common risk factors of ischemic stroke especially in children older than 5 years old. Therefore, we must extensively evaluate all the possible risk factors of ischemic stroke in children. TOAST classification could not be applicable in children because the risk factors of ischemic stroke were extremely variable.