A national pharmacoepidemiological study of antibiotic use in Korean paediatric outpatients.

BACKGROUND: Information on the use of antibiotics in Eastern Asian children is limited. The objectives of this study were to evaluate in Korean paediatric outpatients (1) the nationwide pattern of prescribing antibiotics according to age group and medical institution and (2) the adherence of antibiotic use for acute respiratory tract infections to both national guidelines and European antibiotic prescribing quality indicators. METHOD: This population-based study used the national insurance reimbursement database for 2011. The study subjects were outpatients younger than 18 years old prescribed systemic antibiotics. Patterns of antibiotic prescription were compared according to diagnostic conditions, age group and medical institution. The disease-specific proportion of recommended antibiotic or quinolone use for acute respiratory tract infections was evaluated on the basis of clinical practice guidelines and European quality indicators. RESULTS: The data consisted of 70.7 million prescription records for 7.9 million paediatric outpatients, which means that 79.3% of the whole paediatric population used antibiotics. Broad-spectrum antibiotics made up 78.5% of the prescriptions, with broad-spectrum penicillins such as amoxicillin/clavulanate being the most commonly prescribed (50.2%). They were prescribed more commonly in younger paediatric patients (∼80%) than in adolescents (66.6%). The leading diagnosis accounting for antibiotic prescription was bronchitis (35.9%). The prescription proportion of recommended antibiotics in the European quality indicators was extremely low compared with the national guidelines: <0.1% for pharyngotonsillitis and 13.4% for acute otitis media. CONCLUSIONS: Antibiotic use in children in Korea is inappropriately high. In addition, broad-spectrum antibiotics are used excessively.

Ethnic variability in the allelic distribution of pharmacogenes between Korean and other populations.

OBJECTIVE: We examined the differences in allele frequencies for pharmacogenes among the Korean (KOR), Chinese (CHB), Japanese (JPT), Caucasian (CEU), and Nigerian (YRI) populations. METHODS: Fifty-seven pharmacogenes were selected from the imputed Korean Association REsource and HapMap databases. Minor allele frequencies were analyzed using the sample size-modified single nucleotide polymorphism-specific fixation index (FST) and the χ-test with Bonferroni's correction. Geneset analysis was also carried out to identify pharmacogenes that have significantly different allele frequencies among the various populations tested. RESULTS: The KOR population was the most divergent group from the YRI population (FST: 0.079) but very similar to the CHB and JPT populations (FST: 0.003). VKORC1 showed a large population divergence in the KOR-YRI (0.439) comparison. CYP3A4 was also highly divergent in the KOR-YRI (FST: 0.361) comparison. The calcium signaling pathway gene set was divergent in all pairwise population comparisons. CONCLUSION: In terms of the 57 pharmacogenes studied, there were no significant differences among the KOR, CHB, and JPT populations. However, the YRI and CEU populations were significantly differentiated from the three Eastern Asian groups. Future pharmacogenomics studies can utilize the polymorphisms identified in this study, as these variants may have important implications for the selection of highly informative single nucleotide polymorphisms for future clinical trials.

In vivo MR evaluation of the effect of the CCR2 antagonist on macrophage migration.

The CCR2 antagonist is a receptor antagonist for monocyte chemoattractant protein-1 and is known to be a potential anti-inflammatory therapeutic agent. Recently used optimized labeling techniques for superparamagnetic iron oxide, macrophage homing, and recruitment toward the infection site can be observed on in vivo MRI. This study details the effect of the CCR2 antagonist on the macrophage migration and the feasibility of in vivo MRI for assessing the inhibition of chemotactic activity by the CCR2 antagonist. On binding assay, the CCR2 antagonist inhibits the binding affinity of monocyte chemoattractant protein-1 to CCR2. Increased expression of messenger ribonucleic acid (mRNA) and expression of CCR2 and CD11b on the cellular surface, as induced by monocyte chemoattractant protein-1, was shown, and the effect of monocyte chemoattractant protein-1 on CCR2 and CD11b was restricted by the CCR2 antagonist. In a migration test using the transwell system, macrophages treated with the CCR2 antagonist showed significantly decreased chemotactic migration compared to that of wild-type macrophages. MR images of infected left calf muscles in 12 mice were obtained 24 h after administration of macrophages labeled with superparamagnetic iron oxide. MRI successfully demonstrated the effect of the CCR2 antagonist on the directional migration of macrophages.

Graft rejection in the xenogeneic transplantation of mice: diagnosis with in vivo MR imaging using the homing trait of macrophages.

BACKGROUND: To evaluate the feasibility of magnetic resonance (MR) imaging to depict the in vivo recruitment of superparamagnetic iron oxide (SPIO)-labeled macrophages and to diagnose graft rejection in xenogeneic transplantation. METHODS: We transplanted the trachea of SD rat (xenogeneic) or C3H/HeN mouse (syngeneic) into the left thighs of six male C3H/HeN mice. The SPIO-labeled macrophage was administered through the tail vein 2 days (acute) or 14 days (chronic) after transplantation in each group. The left thighs of the mice were imaged on a 4.7-T MR scanner 24 h after macrophage administration. We evaluated the extent and pattern of the susceptibility effect (macrophage distribution) and compared them in the two groups. The MR findings were then correlated with the histopathologic results. We also measured in both groups the monocyte chemoattractant protein (MCP)-1 level before and 2 days, 2 weeks, and 4 weeks after transplantation. RESULTS: The band-shaped lower signal intensity (SI) zone was noted around the graft in the acute and chronic phases of xenogeneic group and in the acute phase of syngeneic group, but it was not noted in the chronic phase of syngeneic transplantation. The lower SI zone corresponded to the distribution of SPIO-labeled macrophages on histopathological analyses. On histologic examination, the severe inflammation developed around the xenogeneic graft, but only slightly around the syngeneic graft. MCP-1 was elevated 2 days after transplantation in both groups, but then gradually decreased in the syngeneic group; in xenogenic group, the MCP-1 value decreased by week 2 but then increased by week 4. CONCLUSIONS: This study demonstrates that the homing of intravenously administered SPIO-labeled macrophages can be monitored on MR imaging and is correlated with the MCP-1 level and the histopathologic findings of the xenograft rejection.

TIMP-2 promotes cell spreading and adhesion via upregulation of Rap1 signaling.

We previously demonstrated that TIMP-2 treatment of human microvascular endothelial cells (hMVECs) activates Rap1 via the pathway of paxillin-Crk-C3G. Here, we show that TIMP-2 overexpression in hMVECs by adenoviral infection enhances Rap1 expression, leading to further increase in Rap1-GTP. TIMP-2 expression, previously reported to inhibit cell migration, also leads to cell spreading accompanied with increased cell adhesion. HMVECs stably expressing Rap1 display a similar phenotype as hMVECs-TIMP-2, whereas the expression of inactive Rap1 mutant, Rap1(38N), leads to elongated appearance with greatly reduced cell adhesion. Furthermore, the phenotype of hMVECs-Rap1(38N) was not reversed by TIMP-2 overexpression. TIMP-2 greatly promotes the association of Rap1 with actin. Therefore, these findings suggest that TIMP-2 mediated alteration in cell morphology requires Rap1, TIMP-2 may recruit Rap1 to sites of actin cytoskeleton remodeling necessary for cell spreading, and enhanced cell adhesion by TIMP-2 expression may hinder cell migration.