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Articles by S. J Kim
Total Records ( 14 ) for S. J Kim
  S. J Kim and H. S. Toma
 

Objective  To determine the inhibitory effect of intravitreal nonsteroidal anti-inflammatory drugs on choroidal neovascularization (CNV) in an animal model of age-related macular degeneration.

Methods  Six laser burns of sufficient power to rupture the Bruch membrane were induced in the peripapillary area of each eye of 18 adult Brown Norway rats. Both eyes of each animal received the same 5-µL intravitreal injection of 30 mg/mL of ketorolac tromethamine, 40 mg/mL of triamcinolone acetonide, or balanced salt solution. Fluorescein angiography was performed on days 14 and 21 after injection, animals were euthanized, and retinal pigment epithelium–choroid–sclera (choroidal) flat mounts were prepared. Areas of abnormal vascular leakage on fluorescein angiography and vascular budding on choroidal mounts were measured and quantified using an image analysis program.

Results  Intravitreal ketorolac significantly reduced CNV leakage on fluorescein angiography at 2 (P < .001) and 3 (P = .006) weeks compared with eyes injected with balanced salt solution, but intravitreal triamcinolone was a more potent inhibitor of CNV leakage than ketorolac (P < .001). Vascular budding on choroidal mounts was almost entirely suppressed with triamcinolone (P < .001) and significantly inhibited with ketorolac (P = .009).

Conclusion  Intravitreal ketorolac significantly reduced laser-induced CNV leakage and vascular budding as determined by fluorescein angiography and choroidal flat mounts, respectively, although this effect was less than that of triamcinolone.

Clinical Relevance  Intravitreal nonsteroidal anti-inflammatory drugs may be useful in the treatment of CNV owing to age-related macular degeneration or other causes and offer distinct clinical advantages over corticosteroids because of their lack of association with cataract formation or glaucoma.

  Y. J Jang , M. S Park , S. S Park , J. H Kim , H An , S. H Park , S. J Kim , C. S Kim and Y. J. Mok
 

Background  The results of gastric cancer treatment have improved during the past 2 decades. In addition to early diagnosis, surgeon experience and subspecialty may influence long-term outcomes. This study analyzed data accumulated during the past 20 years regarding the impact of surgical subspecialty on gastric cancer prognosis.

Design  A 20-year, retrospective study.

Setting  Korea University Guro Hospital, Seoul.

Patients  A total of 2797 patients admitted between 1984 and 2003 with surgically treated, pathologically confirmed, primary gastric adenocarcinoma.

Main Outcome Measure  Long-term survival.

Results  The incidence of total gastrectomy and the number of retrieved lymph nodes increased during the study period. In curative cases, 5-year survival improved from 66.1% to 76.6%, and this survival gain was restricted to stages I, III, and IV. A Cox proportional hazards regression model showed that age, sex, tumor location, type of resection, stage, and the interaction between period of study and surgical subspecialty were independent prognostic factors.

Conclusions  This large, long-term cohort study demonstrates that the management of gastric cancer has been largely successful, with favorable trends in prognostic factors. Successful outcomes are realized more often by gastric surgical specialists. Efforts must be made to improve the treatment of patients with stage II gastric cancer because the improvements in long-term results have plateaued.

  K. Y Yoo , C. W Jeong , B. Y Park , S. J Kim , S. T Jeong , M. H Shin and J. Lee
  Background

We examined the effects of remifentanil on cardiovascular and bispectral index (BIS) responses to tracheal intubation and neonatal outcomes in pre-eclamptic patients undergoing Caesarean delivery under general anaesthesia.

Methods

Forty-two women with severe pre-eclampsia were randomly assigned to receive either remifentanil 1 µg kg–1 (n=21) or saline (n=21) over 30 s before induction of anaesthesia using thiopentone 4 mg kg–1 and suxamethonium 1.5 mg kg–1. Mean arterial pressure (MAP), heart rate (HR) and BIS values as well as plasma catecholamine concentrations were measured. Neonatal effects were assessed using Apgar scores and umbilical cord blood gas analysis.

Results

Induction with thiopentone caused a reduction in MAP and BIS in both remifentanil and control groups. Following the tracheal intubation MAP and HR increased in both groups, the magnitude of which was lower in the remifentanil group. BIS values also increased, of which magnitude did not differ between the groups. Norepinephrine concentrations increased significantly following the intubation in the control, while remained unaltered in the remifentanil group. The neonatal Apgar scores at 1 min were significantly lower in the remifentanil group than in the control. However, Apgar scores at 5 min, and umbilical artery and vein blood gas values were similar between the groups.

Conclusions

These results suggest that a single bolus of 1 µg kg–1 remifentanil effectively attenuates haemodynamic but not BIS responses to tracheal intubation in pre-eclamptic patients undergoing Caesarean delivery under general anaesthesia. However, its use was associated with maternal hypotension and neonatal respiratory depression requiring resuscitation.

  K. Y Yoo , C. W Jeong , S. J Kim , S. T Jeong , S. H Kwak , M. H Shin and J. Lee
  Background

We determined cardiovascular responses to tracheal intubation in relation to the time since injury in patients with different levels of spinal cord injury.

Methods

Two hundred and fourteen patients with complete cord injury were studied. They were either quadriplegics (>C7, n=71) or paraplegics (<T5, n=143), and were subdivided into six groups each according to the time since injury: <4 week (acute), 4 week–1 yr, 1–5, 5–10, 10–20, and >20 yr. Twenty patients with no cord injury served as controls. Systolic arterial pressure (SAP), heart rate (HR), and plasma catecholamine concentrations were determined.

Results

Intubation did not affect SAP in the quadriplegics regardless of the time post-injury, but it significantly increased SAP in all paraplegics. Moreover, the pressor response was enhanced in the paraplegics who were 10 yr or more since injury (P<0.05). HR increased significantly in all groups; the magnitude of the increase was less only in acute quadriplegics compared with controls. Plasma concentrations of norepinephrine increased in every group except for the quadriplegics within 4 weeks of injury. The maximum increases in SAP, HR, and norepinephrine from awake baseline values were smaller in the quadriplegics than in the paraplegics (P<0.01).

Conclusions

The cardiovascular and catecholamine responses to intubation change as a function of the time elapsed and the level of the cord injury. In this study, the pressor response to tracheal intubation was abolished in the quadriplegics but not in paraplegics; indeed, it was enhanced at 10 yr or more since injury in this group.

  S. J Park , H. Y Yoo , Y. E Earm , S. J Kim , J. K Kim and S. D. Kim
  Background

The roles of arachidonic acid (AA) metabolites in hypoxia-induced pulmonary vasoconstriction (HPV), a critical physiological mechanism that prevents ventilation/perfusion mismatch, are still incompletely understood.

Methods

Pulmonary arterial pressure was measured in ventilated/perfused rat lungs. Isometric tones of rat intralobar pulmonary arteries were also measured, using a myograph.

Results

Hypoxia (Po2, 3%)-induced pulmonary arterial pressure increases (PAPhypox) were stable with blood-mixed perfusate, but decayed spontaneously. PAPhypox was inhibited by 29%, 16%, and 28% by the thromboxane A2 (TXA2) antagonist SQ-29548, the 5-lipoxygenase inhibitor, MK886, and the leukotriene D4 antagonist, LY-171883, respectively. The prostacyclin synthase inhibitor tranylcypromine augmented PAPhypox by 5%, whereas inhibition of cytochrome P450 did not affect PAPhypox. Consistently, the TXA2 analogue U46619 increased PAPhypox whereas prostacyclin abolished PAPhypox. However, leukotriene D4 had no direct effect on PAPhypox. In the isolated pulmonary arteries, pretreatment with U46619 was essential to demonstrate hypoxia-induced contraction.

Conclusions

The above results suggest that TXA2 and cysteinyl leukotrienes, other than leukotriene D4, are endogenous factors that facilitate HPV in rats. The indispensable role of TXA2-induced pretone in the HPV of isolated pulmonary arteries indicates that the signal from thromboxane receptors might be a critical component of oxygen sensation mechanisms.

  B. Y Park , C. W Jeong , E. A Jang , S. J Kim , S. T Jeong , M. H Shin , J Lee and K. Y. Yoo
  Background

The optimal dose of remifentanil to attenuate the cardiovascular responses to tracheal intubation in pre-eclamptic patients undergoing Caesarean delivery under general anaesthesia has not been established. We compared the effects of two low doses of remifentanil on the cardiovascular responses to tracheal intubation and neonatal outcomes.

Methods

Forty-eight women with severe pre-eclampsia were randomly assigned to receive either remifentanil 0.5 µg kg–1 (R0.5 group, n=24) or 1 µg kg–1 (R1.0 group, n=24) over 30 s before induction of anaesthesia using thiopental 5 mg kg–1 and succinylcholine 1.5 mg kg–1. Systolic arterial pressure (SAP), heart rate (HR), and plasma catecholamine concentrations were measured. Neonatal effects were assessed using Apgar scores and umbilical cord blood gas analysis.

Results

SAP was decreased by induction of anaesthesia and increased by tracheal intubation in both groups. The peak SAP after intubation was greater in the R0.5 group than in the R1.0 group, whereas it did not exceed baseline values in either group. HR increased significantly above baseline in both groups with no significant differences between the groups. Three subjects in the R1.0 group received ephedrine due to hypotension (SAP<90 mm Hg). Norepinephrine concentrations remained unaltered after intubation and increased significantly at delivery with no significant differences between the groups. Neonatal Apgar scores and umbilical arterial and venous pH and blood gas values were comparable between the groups.

Conclusions

Both doses of remifentanil effectively attenuated haemodynamic responses to tracheal intubation with transient neonatal respiratory depression in pre-eclamptic patients undergoing Caesarean delivery under general anaesthesia. The 1.0 µg kg–1 dose was associated with hypotension in three of 24 subjects.

  H Hotta , T Miura , T Miki , N Togashi , T Maeda , S. J Kim , M Tanno , T Yano , A Kuno , T Itoh , T Satoh , Y Terashima , S Ishikawa and K. Shimamoto
 

Rationale: The diabetic heart is resistant to ischemic preconditioning because of diabetes-associated impairment of phosphatidylinositol 3-kinase (PI3K)-Akt signaling. The mechanism by which PI3K-Akt signaling is impaired by diabetes remains unclear.

Objective: Here, we examined the hypothesis that phosphorylation of Jak2 upstream of PI3K is impaired in diabetic hearts by an angiotensin II type 1 (AT1) receptor–mediated mechanism.

Methods and Results: Infarct size (as percentage of risk area) after 20-minute ischemia/2-hour reperfusion was larger in a rat model of type 2 diabetes (Otsuka–Long–Evans–Tokushima fatty [OLETF] rat) than in its control (Long–Evans–Tokushima–Otsuka [LETO] rat) (60.4±1.6% versus 48.4±1.3%). Activation of Jak2-mediated signaling by erythropoietin or DADLE ([d-Ala2, d-Leu5]-enkephalin acetate), a -opioid receptor agonist, limited infarct size in LETO rats (27.7±3.4% and 24.8±5.0%) but not in OLETF rats (53.9±5.3% and 55.0±2.2%). Blockade of the AT1 receptor by valsartan or losartan for 2 weeks restored the myocardial response of OLETF rats to erythropoietin-induced infarct size limitation (39.4±4.9% and 31.2±7.5). In OLETF rats, erythropoietin failed to phosphorylate both Jak2 and Akt, and calcineurin activity was significantly higher than in LETO rats. Two-week treatment with valsartan normalized calcineurin activity in OLETF rats and restored the response of Jak2 to erythropoietin. This effect of AT1 receptor blockade was mimicked by inhibition of calcineurin by FK506.

Conclusions: These results suggest that the diabetic heart is refractory to protection by Jak2-activating ligands because of AT1 receptor–mediated upregulation of calcineurin activity.

  J. Y Um , C. H Jang , K. Y Kim , S. J Kim , N. H Kim , P. D Moon , I. Y Choi , N. Y Myung , H. J Jeong , S. H Hong and H. M. Kim
 

Auditory dysfunction is related to large/small vessel occlusions and hemorrhage. Sudden sensorineural hearing loss (SSNHL) frequently occurs with anterior inferior cerebellar artery occlusion proximal to the internal auditory artery. Moreover, SSNHL has various pathogenetic mechanisms, the main proposed mechanisms being vascular disease, membrane ruptures, infection, and autoimmunity. Tumor necrosis factor (TNF) is an important cytokine in the inflammation process of cerebrovascular diseases. In the current study, the possible effects of polymorphisms in TNF- and TNF-β genes on SSNHL are evaluated. Two genetic polymorphisms in the TNF locus (TNF- —308 G - ->A and TNF-β +252 A - ->G) were investigated as risk factors for SSNHL by determining their prevalence in 97 SSNHL patients and in 587 controls. A significant increase was found for the TNF-β allele 1 in SSNHL patients compared with the controls ( 2 = 7.251, P = .007, odds ratio [OR] = 1.534, confidence interval [CI] = 1.12-2.10). These findings suggest that the TNF-β +252 locus plays an important role in the etiopathogenesis of SSNHL.

  T Tanei , K Morimoto , K Shimazu , S. J Kim , Y Tanji , T Taguchi , Y Tamaki and S. Noguchi
 

Purpose: Breast cancer stem cells have been shown to be associated with resistance to chemotherapy in vitro, but their clinical significance remains to be clarified. The aim of this study was to investigate whether cancer stem cells were clinically significant for resistance to chemotherapy in human breast cancers.

Experimental Design: Primary breast cancer patients (n = 108) treated with neoadjuvant chemotherapy consisting of sequential paclitaxel and epirubicin-based chemotherapy were included in the study. Breast cancer stem cells were identified by immunohistochemical staining of CD44/CD24 and aldehyde dehydrogenase 1 (ALDH1) in tumor tissues obtained before and after neoadjuvant chemotherapy. CD44+/CD24 tumor cells or ALDH1-positive tumor cells were considered stem cells.

Results: Thirty (27.8%) patients achieved pathologic complete response (pCR). ALDH1-positive tumors were significantly associated with a low pCR rate (9.5% versus 32.2%; P = 0.037), but there was no significant association between CD44+/CD24 tumor cell proportions and pCR rates. Changes in the proportion of CD44+/CD24 or ALDH1-positive tumor cells before and after neoadjuvant chemotherapy were studied in 78 patients who did not achieve pCR. The proportion of ALDH1-positive tumor cells increased significantly (P < 0.001) after neoadjuvant chemotherapy, but that of CD44+/CD24 tumor cells did not.

Conclusions: Our findings suggest that breast cancer stem cells identified as ALDH1-positive, but not CD44+/CD24, play a significant role in resistance to chemotherapy. ALDH1-positive thus seems to be a more significantly predictive marker than CD44+/CD24 for the identification of breast cancer stem cells in terms of resistance to chemotherapy.

  H. Y Seo , J. M Park , K. H Park , S. J Kim , S. C Oh , B. S Kim , Y. H Kim and J. S. Kim
  Objective

Angiogenesis is one of the crucial steps in various solid tumor growth and metastasis. However, there are limited data regarding the clinical and prognostic significance of serum vascular endothelial growth factor levels per platelet count in unresectable advanced gastric cancer compared with early gastric cancer and healthy volunteers.

Methods

A total of 181 gastric cancer patients were included and control serum samples were acquired from 113 healthy volunteers. The levels of serum vascular endothelial growth factor were measured using human vascular endothelial growth factor quantitative enzyme-linked immunosorbent assay. Survival curves were calculated using the Kaplan–Meier method and survival comparisons were made by the log-rank test in metastatic gastric cancer.

Results

There was a significant correlation between serum vascular endothelial growth factor levels and differentiation of tumor (P = 0.014), stage (P = 0.036). The overall survival (P = 0.0432) and the progression-free survival (P = 0.0116) were significantly shorter in patients with high serum vascular endothelial growth factor per platelet count (≥1.626 pg/106). In the multivariate analysis, the presence of peritoneal carcinomatosis (P = 0.039), serum vascular endothelial growth factor per platelet (P = 0.005) were found to be significantly associated with poor progression-free survival.

Conclusions

This study demonstrates that serum vascular endothelial growth factor per platelet count is correlated with poor overall survival and progression-free survival in patients with advanced gastric cancer.

  S. J Park , Y. S Chun , K. S Park , S. J Kim , S. O Choi , H. L Kim and J. W. Park
 

Hypoxic inhibition of K+ current is a critical O2-sensing mechanism. Previously, it was demonstrated that the cooperative action of TASK-1 and NADPH oxidase-4 (NOX4) mediated the O2-sensitive K+ current response. Here we addressed the O2-sensing mechanism of NOX4 in terms of TASK-1 regulation. In TASK-1 and NOX4-coexpressing human embryonic kidney 293 cells, hypoxia (5% O2) decreased the amplitude of TASK-1 current (hypoxia-ITASK-1). To examine whether reactive oxygen species (ROS) mediate the hypoxia-ITASK-1, we treated the cells with carbon monoxide (CO) which is known to reduce ROS generation from the heme-containing NOX4. Unexpectedly, CO failed to mimic hypoxia in TASK-1 regulation, rather blocked the hypoxia-ITASK-1. Moreover, the hypoxia-ITASK-1 was neither recovered by H2O2 treatment nor prevented by antioxidant such as ascorbic acid. However, the hypoxia-ITASK-1 was noticeably attenuated by succinyl acetone, a heme synthase inhibitor. To further evaluate the role of heme, we constructed and expressed various NOX4 mutants, such as HBD(–) lacking the heme binding domain, NBD(–) lacking the NADPH binding domain, FBD(–) lacking the FAD binding domain, and HFBD(–) lacking both heme and FAD domains. The hypoxia-ITASK-1 was significantly reduced in HBD(–)-, FBD(–)-, or HFBD(–)-expressing cells, versus wild-type NOX4-expressing cells. However, NBD(–) did not affect the TASK-1 response to hypoxia. We also found that p22 is required for the NOX4-dependent TASK-1 regulation. These results suggest that O2 binding with NOX4 per se controls TASK-1 activity. In this process, the heme moiety and FBD seem to be responsible for the NOX4 regulation of TASK-1, and p22 might support the NOX4-TASK-1 interaction.

  S. J Kim , K. H Park , S. H Kim , S. G Kim and Y. M. Chun
 

Background: Recent reports revealed that outcomes of anterior cruciate ligament (ACL) reconstruction in middle- or old-age patients are comparable with those of young patients. However, in case of concomitant arthrosis in the affected knee, there has been a paucity of literature regarding the outcomes of ACL reconstruction. We studied the level of improvement in pain originating from significant cartilage degeneration in middle-aged ACL-deficient patients after ACL reconstruction. We divided the pain into pain at rest and activity-induced pain.

Hypothesis: The activity-induced pain would be more improved by ACL reconstruction than the pain at rest.

Study Design: Case series; Level of evidence, 4.

Methods: We studied 36 patients who had undergone arthroscopic isolated ACL reconstruction for functional instability with significant cartilage degeneration grade III or IV without mensical injury. All patients had activity-induced pain; 20 of these patients also had pain at rest. To assess the pain level, the visual analog scale (VAS) was employed, in addition to radiologic and clinical evaluations such as the Lachman test, KT-2000 arthrometer, and pivot shift test. The mean age of the patients was 48.6 years (range, 41-61 years); mean follow-up was 46.7 months (range, 27-74 months).

Results: The preoperative mean VAS of the activity-induced pain (4.1 ± 1.0; range, 2-6) showed significant improvement at the most recent follow-up (2.0 ± 1.0; range, 0-4; P < .0001). However, the preoperative mean VAS of the pain at rest (2.9 ± 0.9; range, 2-5) did not improve significantly at the most recent follow-up (2.5 ± 0.8; range, 1-4; P = .149). The Lachman test, KT-2000 arthrometer, andpivot shift test showed significant improvement compared with preoperative outcomes (P < .0001). There was no significant difference in radiologic assessment between preoperative and postoperative outcomes (P = .082).

Conclusion: Anterior cruciate ligament reconstruction in middle-aged patients with significant cartilage degeneration is effective in reducing activity-induced pain and instability. Even though all patients had less than severe arthritic changes on preoperative radiographs, the pain at rest did not improve after ACL reconstruction.

  N Krishnan , D. G Jeong , S. K Jung , S. E Ryu , A Xiao , C. D Allis , S. J Kim and N. K. Tonks
 

In mammalian cells, the DNA damage-related histone H2A variant H2A.X is characterized by a C-terminal tyrosyl residue, Tyr-142, which is phosphorylated by an atypical kinase, WSTF. The phosphorylation status of Tyr-142 in H2A.X has been shown to be an important regulator of the DNA damage response by controlling the formation of H2A.X foci, which are platforms for recruiting molecules involved in DNA damage repair and signaling. In this work, we present evidence to support the identification of the Eyes Absent (EYA) phosphatases, protein-tyrosine phosphatases of the haloacid dehalogenase superfamily, as being responsible for dephosphorylating the C-terminal tyrosyl residue of histone H2A.X. We demonstrate that EYA2 and EYA3 displayed specificity for Tyr-142 of H2A.X in assays in vitro. Suppression of eya3 by RNA interference resulted in elevated basal phosphorylation and inhibited DNA damage-induced dephosphorylation of Tyr-142 of H2A.X in vivo. This study provides the first indication of a physiological substrate for the EYA phosphatases and suggests a novel role for these enzymes in regulation of the DNA damage response.

 
 
 
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