Yun-Sik Yang

Identification of polymorphisms in human interleukin-27 and their association with asthma in a Korean population

AbstractInterleukin 27 (IL-27) acts as a versatile cytokine in the early regulation of Th1 initiation and in the negative regulation of the Th2 factor GATA-3. IL-27, which was discovered as a novel heterodimeric cytokine of the IL-12 family, consists of two subunits, the Epstein-Barr virus-induced gene 3 (EBI3) and p28. The IL-27 cytokine is mediated by one of the receptor chains (WSX-1) of the IL-27 receptor that is highly expressed on CD4+ T lymphocytes and NK cells. Although signaling of IL-27/WSX-1 interactions have been recognized in the down-regulation of airway hyper-reactivity and in lung inflammation during the development of allergic asthma, little is known about the role of single nucleotide polymorphisms (SNPs) of IL-27 and individual susceptibility to asthma. To address this question, we have examined the five exons and the boundary intron sequences of IL-27P28, including the promoter regions, with the aim of identifying sites of variation that may be useful for understanding the genetic influences of this gene. We identified four SNPs, g.-964A > G, g.2905T > G, g.4603G > A and g.4730T > C, and analyzed the genotype and allele frequencies between asthma patients and healthy controls. Our results strongly suggest that the g.-964A > G polymorphism of IL-27p28 is most likely associated with susceptibility to asthma. Moreover, we elucidate the haplotype frequencies of g.2905T > G, g.4603G > A and g.4730T > C in terms of their relative correlation with asthma patients and healthy controls.

p-Glycoprotein ABCB5 and YB-1 expression plays a role in increased heterogeneity of breast cancer cells: correlations with cell fusion and doxorubicin resistance.

BackgroundCancer cells recurrently develop into acquired resistance to the administered drugs. The iatrogenic mechanisms of induced chemotherapy-resistance remain elusive and the degree of drug resistance did not exclusively correlate with reductions of drug accumulation, suggesting that drug resistance may involve additional mechanisms. Our aim is to define the potential targets, that makes drug-sensitive MCF-7 breast cancer cells turn to drug-resistant, for the anti-cancer drug development against drug resistant breast cancer cells.MethodsDoxorubicin resistant human breast MCF-7 clones were generated. The doxorubicin-induced cell fusion events were examined. Heterokaryons were identified and sorted by FACS. In the development of doxorubicin resistance, cell-fusion associated genes, from the previous results of microarray, were verified using dot blot array and quantitative RT-PCR. The doxorubicin-induced expression patterns of pro-survival and pro-apoptotic genes were validated.ResultsYB-1 and ABCB5 were up regulated in the doxorubicin treated MCF-7 cells that resulted in certain degree of genomic instability that accompanied by the drug resistance phenotype. Cell fusion increased diversity within the cell population and doxorubicin resistant MCF-7 cells emerged probably through clonal selection. Most of the drug resistant hybrid cells were anchorage independent. But some of the anchorage dependent MCF-7 cells exhibited several unique morphological appearances suggesting minor population of the fused cells maybe de-differentiated and have progenitor cell like characteristics.ConclusionOur work provides valuable insight into the drug induced cell fusion event and outcome, and suggests YB-1, GST, ABCB5 and ERK3 could be potential targets for the anti-cancer drug development against drug resistant breast cancer cells. Especially, the ERK-3 serine/threonine kinase is specifically up-regulated in the resistant cells and known to be susceptible to synthetic antagonists.

Primary Pterygium Surgery Using the Inferior Conjunctival Transposition Flap

The authors investigated a surgical method for primary pterygium without adjunctive therapy and devised a technique called the inferior conjunctival transposition flap. The procedure was performed by making a flap of the inferior conjunctiva after excision of the pterygium, and transpositioning it to make a covering for the bare sclera and donor site and a barrier to pterygium tissue. This method has been used on 54 eyes of 50 patients (mean age 47 years, range 18 to 69 years) with primary pterygium. All of these patients were treated by one surgeon. During a follow-up period of 12 to 26 months (mean 20 months), the pterygium recurred in 3 (5.6%) of the 54 eyes. In all other cases good anatomic and cosmetic results were achieved without any serious complications. The authors concluded that the inferior conjunctival transposition flap is an encouraging technique for the treatment of primary pterygium.

Analysis of the variations in IL-28RA gene and their association with allergic rhinitis.

IL-28RA is one of the important candidate genes for complex trait of genetic diseases, but there is no published information of the genetic variation in this gene. We scanned the seven exons and their boundary introns sequence of IL-28RA including the promoter regions to analyze genetic variation sites, and identified eighteen single nucleotide polymorphisms (SNPs) and two variation sites. We chose seven SNPs (g.-1193 A>C, g.-30 C>T, g.17654 C>T, g.27798 A>G, g.31265 C>T, g.31911 C>T and g.32349 G>A) of them for large sample size genotyping, and assessed the association of genotype and allele frequencies of these SNPs between allergic rhinitis patients and non-allergic rhinitis controls. We also compared the genotype frequencies between Korean controls and Han Chinese control or Korean Chinese control. We investigated the frequencies of haplotype constructed by these SNPs between allergic rhinitis patients and non-allergic rhinitis controls. Our results suggested that the g.32349 G>A polymorphism of IL-28RA might be associated with susceptibility to allergic rhinitis (P=0.032), but seems to have no relationship with serum total IgE levels. The haplotype frequencies by these SNPs also show significant association between controls and allergic rhinitis patients.

Tolerance of patients and postoperative results : Topical anesthesia for strabismus surgery

PURPOSE To assess patient tolerance and the postoperative results of intraoperative adjustment of strabismus surgery under topical anesthesia. METHODS Twenty-four patients with strabismus underwent rectus muscle recession under topical anesthesia without the use of additional systemic analgesics and sedatives. Patient tolerance was estimated according to the sites of procedure. In addition, the angle of strabismus was measured 1 day, 6 weeks, and 1 year postoperatively. RESULTS Of the 24 patients identified (11 men and 13 women; mean age: 24 years), 16 had exotropia, 7 were esotropic, and 1 was hypertropic. During the operation, 17 patients never expressed any pain, and 7 patients complained of discomfort on muscle manipulation. Postoperatively, the success rate was 95.8% (23 patients) the first day after surgery, 79.2% (19 patients) after 6 weeks, and 70.8% (17 patients) after 1 year. CONCLUSION Intraoperative adjustment performed with the patient under topical anesthesia is recommended in all cooperative cases of strabismus surgery and is comfortable for patients.

Identification of single nucleotide polymorphisms in the TNFRSF17 gene and their association with gastrointestinal disorders

TNFRSF17 is preferentially expressed in mature B lymphocytes, and may be important for the development of B cells. TNFRSF17 is selected as a candidate susceptibility gene to IBD pathogenesis by our cDNA microarray analysis, and we showed the specific expression of TNFRSF17 in resting and activated CD19+ cells obtained from human blood. We identified four SNPs (g-1729G>A, g.2295T>C, g.2445G>A and g.2493G>A) and one variation site (g.894delT) in the TNFRSF17 gene using direct sequencing analysis. In addition, the association of the genotype and allelic frequencies of these SNPs was studied in healthy controls and in patients with ulcerative colitis (UC) or irritable bowel syndrome (IBS). Although, the genotype and allelic frequencies of these SNPs, in the UC and IBS patients, were not significantly different from those in the healthy controls, the distribution of the AAG, GGA, AGG and AAA haplotypes, of the SNPs (g.-1729G>A, g.2445G> A and g.2493G>A) associated with the TNFRSF17 gene, in the UC patients, were notably different from those of the healthy controls (P = 0.002, 0.002, 4.7E-4 and 3.3E-6, respectively). Moreover, the frequencies of the AAG, AGG, GAG and GAA haplotypes were significantly different in the IBS patients compared to the healthy controls (P = 4.2E-5, 4.4E-17, 1.8E-22 and 1.6E-10, respectively). These results suggest that the haplotypes of the TNFRSF17 polymorphisms might be associated with UC and IBS susceptibility.

Sudden unilateral blindness after intracranial aneurysm surgery

SummaryThe incidence of unilateral blindness and ophthalmoplegia after aneurysm surgery is very rare, but if it occurs, it is mainly caused by intra-operative nerve injury. We experienced 6 cases of unilateral blindness immediately after surgery for 3 recent years. These patients were classified into Hunt-Hess grade I to II except for one patient with III. All patients complained of visual loss with varying degree of lid oedema and ophthalmoplegia ipsilateral to the site of surgery. Angiographic examination of these patients revealed that the aneurysm was located at the internal carotid artery bifurcation in one case and the middle cerebral artery bifurcation in five cases. All of them were relatively far from the optic nerve. The aneurysm was clipped easily with minimal brain retraction via standard pterional craniotomy since the brain was slack in all cases. In all cases, injuring the optic nerve during surgery was remote. All patients showed evidence of retinal ischaemia on fundoscopy with or without fluorescein angiography.The pathophysiology of this ischaemic event is unknown. In our patients, we could exclude possible aetiological factors such as abnormal systemic and ocular conditions, causing ischaemia in intra-orbital structures, increased intracranial pressure, intra-operative hypotension, carotid atherosclerosis, and ocular vasospasm etc. Accordingly we speculate that the complications seen in our cases were most likely related to intra-orbital ischaemia initiated by a collapse of the arterial and venous channels in the orbit and/or to direct or indirect contusion on the intra-orbital structures. These situations could be produced by inadvertent pressure placed on the eyeball with a bulky retracted frontal skin flap.Visual acuity in these patients ranged from no light perception to the ability to see objects and detect colour. Their conditions were irreversible. The degree of visual recovery seems to be dependent on the duration and severity of retinal ischaemia by orbital compression. Unfortunately there is no satisfactory treatment. We recommend the use of an eye shield to protect ipsilateral eyeball just before aneurysm surgery.

Significant association between IL-17F promoter region polymorphism and susceptibility to asthma in a Korean population.

Background: Individual differences in susceptibility to asthma would be expected because of common DNA variants of single nucleotide polymorphisms (SNPs) across populations. The pro-inflammatory cytokine IL-17F has homology with the IL-17 motif and induces the expression of other inflammatory cytokines in airway epithelial cells. This study aimed to identify IL-17F gene polymorphisms and to determine a possible association between these polymorphisms and susceptibility to asthma through a case-control study in a Korean population. Methods: We identified SNPs in the IL-17F gene by sequencing. Genotyping was conducted using the high-resolution melting (HRM) method on 424 asthma patients and 548 healthy controls. Results: The genotype and allele frequencies of rs1889570 SNP were significantly different between asthma patients and healthy controls (p = 0.001 and 0.002, respectively). The rs1889570 SNP genotype was also positively associated with the number of peripheral blood eosinophils in asthma patients (p = 0.03). The frequencies of haplotypes AA (p = 0.01), GG (p = 0.01) and AG (p = 0.006) were significantly different between asthma patients and healthy controls. Conclusions: In this study, we confirmed that the rs1889570 polymorphism of the IL-17F gene is associated with susceptibility to asthma in a Korean population.

Putative association of RUNX1 polymorphisms with IgE levels in a Korean population.

RUNX1, a member of the runt domain gene family of transcription factors, encodes a heterodimeric transcription factor and regulates the expression of various genes related to hematopoiesis and myeloid differentiation. RUNX1 has been one of the target genes for research into various autoimmune diseases due to its properties as a transcription factor and functional distribution for chromosomal translocation. In an effort to identify additional gene polymorphisms in which variants have been implicated in asthma, we investigated the genetic polymorphisms in RUNX1 to evaluate it as a potential candidate gene for a host genetic study of asthma and IgE production. We identified 19 sequence variants by direct DNA sequencing in 24 individuals of which four common variants were selected for genotyping in our asthma cohort (1,055 asthmatic patients, 384 normal controls). Using logistic regression analysis for association with the risk of asthma, while controlling for age, gender, and smoking status as covariates, no significant associations with the risk of asthma were detected. However, two polymorphisms in the promoter region (-2084G>C and -1282G>A) showed a marginal association with total IgE levels (0.03 and 0.03 in recessive models, respectively). Our findings suggest that polymorphisms in RUNX1 might be one of the genetic factors for the regulation of IgE production.

Visualization of retinal and choroidal blood flow with fluorescein leukocyte angiography in rabbits

Abstract• Purpose: To visualize the retinal and choroidal leukocytes in rabbits with a new technique, fluorescein leukocyte angiography using a scanning laser ophthalmoscope. • Methods: Blood was withdrawn from an ear vein of a rabbit (New Zealand White), mixed with fluorescein dye in a test tube and centrifuged. The yellow-brown coat layer containing fluorescein-stained leukocytes was collected and injected into the ear vein of the same rabbit while performing fluorescein angiography with a scanning laser ophthalmoscope. The angiographic image displaying circulating fluorescent leukocytes in retinal and choroidal vessels was recorded on a videotape. • Results: Fluorescent leukocytes were clearly visible in the retinal arteries, capillaries, veins and choroidal vessels for more than 1 h. Plugging of leukocytes was seen throughout this period of time in choroidal vessels, while plugging was rare in retinal vessels. • Conclusions: Fluorescein leukocyte angiography is a new technique which can be used for visualization of the leukocytes in retinal and choroidal vessels non-invasively and in vivo.