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Role of dopamine D2 receptors in optimizing choice strategy in a dynamic and uncertain environment
Kwak, Shinae,Huh, Namjung,Seo, Ji-Seon,Lee, Jung-Eun,Han, Pyung-Lim,Jung, Min W. Frontiers Media S.A. 2014 Frontiers in Behavioral Neuroscience Vol.8 No.-
<P>In order to investigate roles of dopamine receptor subtypes in reward-based learning, we examined choice behavior of dopamine D1 and D2 receptor-knockout (D1R-KO and D2R-KO, respectively) mice in an instrumental learning task with progressively increasing reversal frequency and a dynamic two-armed bandit task. Performance of D2R-KO mice was progressively impaired in the former as the frequency of reversal increased and profoundly impaired in the latter even with prolonged training, whereas D1R-KO mice showed relatively minor performance deficits. Choice behavior in the dynamic two-armed bandit task was well explained by a hybrid model including win-stay-lose-switch and reinforcement learning terms. A model-based analysis revealed increased win-stay, but impaired value updating and decreased value-dependent action selection in D2R-KO mice, which were detrimental to maximizing rewards in the dynamic two-armed bandit task. These results suggest an important role of dopamine D2 receptors in learning from past choice outcomes for rapid adjustment of choice behavior in a dynamic and uncertain environment.</P>
Jung, Ahjin,Yun, Ji-Sook,Kim, Shinae,Kim, Sang Ryong,Shin, Minsang,Cho, Dong Hyung,Choi, Kwang Shik,Chang, Jeong Ho Korean Society for Molecular and Cellular Biology 2019 Molecules and cells Vol.42 No.1
Histidine triad nucleotide-binding protein (HINT) is a member of the histidine triad (HIT) superfamily, which has hydrolase activity owing to a histidine triad motif. The HIT superfamily can be divided to five classes with functions in galactose metabolism, DNA repair, and tumor suppression. HINTs are highly conserved from archaea to humans and function as tumor suppressors, translation regulators, and neuropathy inhibitors. Although the structures of HINT proteins from various species have been reported, limited structural information is available for fungal species. Here, to elucidate the structural features and functional diversity of HINTs, we determined the crystal structure of HINT from the pathogenic fungus Candida albicans (CaHINT) in complex with zinc ions at a resolution of $2.5{\AA}$. Based on structural comparisons, the monomer of CaHINT overlaid best with HINT protein from the protozoal species Leishmania major. Additionally, structural comparisons with human HINT revealed an additional helix at the C-terminus of CaHINT. Interestingly, the extended C-terminal helix interacted with the N-terminal loop (${\alpha}1-{\beta}1$) and with the ${\alpha}3$ helix, which appeared to stabilize the dimerization of CaHINT. In the C-terminal region, structural and sequence comparisons showed strong relationships among 19 diverse species from archea to humans, suggesting early separation in the course of evolution. Further studies are required to address the functional significance of variations in the C-terminal region. This structural analysis of CaHINT provided important insights into the molecular aspects of evolution within the HIT superfamily.
( Shina Jang ),( Su Gyung Jung ),( Hwoa Yeon Choi ),( Eun Ae Jo ),( Hyung Eun Choi ),( Sung Ook Hwang ),( Soo Ran Choi ) 대한산부인과학회 2019 대한산부인과학회 학술대회 Vol.105 No.-
Objective: Acute histologic chorioamnionitis (HCA) is frequently observed after preterm birth and is associated with the risk of neonatal morbidity and mortality. We aimed to evaluate the relationship between immediately afterbirth oral suction matrix metalloproteinase-8 (MMP-8) and acute HCA in preterm birth. Methods: 93 consecutive patients who delivered preterm neonates (gestational age, from 24+0 weeks to 36+6 weeks) were included. The concentrations of immediately afterbirth oral suction MMP-8 and interleukin-8 (IL-8) were measured by ELISA. Acute HCA was defined as the presence of neutrophils infiltration into the fetal membranes. Logistic regression analysis was used for analysis. Results: Immediately afterbirth oral suction MMP-8 concentrations were significantly higher in patients with acute HCA than in those without acute HCA (median [range]; 65.3ng/ml [0.03-12479.6] versus 9.86ng/ml [0.02-1808.2], p=0.027). There was a strong association between MMP-8 and IL-8 (p<0.001). The diagnostic indices of MMP-8 (cutoff, 39.7ng/ml) in the identification of acute HCA were: sensitivity of 57.7% specificity of 83.6%. Based on a multivariable logistic regression analysis, immediately afterbirth oral suction MMP-8 (p=0.008, odds ratio [OR]=5.36, 95% confidence interval [CI]=1.56-18.37) was associated acute HCA. Conclusion: There is a significantly association between increased levels of immediately afterbirth oral suction MMP-8 and acute HCA.
Technique failure in Korean incident peritoneal dialysis patients: a national population-based study
( Shina Lee ),( Hyunwook Kim ),( Kyoung Hoon Kim ),( Hoo Jae Hann ),( Hyeong Sik Ahn ),( Seung-jung Kim ),( Duk-hee Kang ),( Kyu Bok Choi ),( Dong-ryeol Ryu ) 대한신장학회 2016 Kidney Research and Clinical Practice Vol.35 No.4
Background: Technique failure is an important issue for peritoneal dialysis (PD) patients. In this study, we aimed to analyze technique failure rate in detail and to determine the predictors for technique failure in Korea. Methods: We identified all patients who had started dialysis between January 1, 2005, and December 31, 2008, in Korea, using the Korean Health Insurance Review and Assessment Service database. A total of 7,614 PD patients were included, and the median follow-up was 24.9 months. Results: The crude incidence rates of technique failure in PD patients were 54.1 per 1,000 patient-years. The cumulative 1-, 2-, and 3-year technique failure rates of PD patients were 4.9%, 10.3%, and 15.6%, respectively. However, those technique failure rates by Kaplan-Meier analysis were overestimated compared with the values by competing risks analysis, and the differences increased with the follow-up period. In multivariate analyses, diabetes mellitus and Medical Aid as a crude reflection of low socioeconomic status were independent risk factors in both the Cox proportional hazard model and Fine and Gray subdistribution model. In addition, cancer was independently associated with a lower risk of technique failure in the Fine and Gray model. Conclusion: Technique failure was a major concern in patients initiating PD in Korea, especially in diabetic patients and Medical Aid beneficiaries. The results of our study offer a basis for risk stratification for technique failure. Copyright ⓒ 2016. The Korean Society of Nephrology. Published by Elsevier. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
( Shina Lee ),( Jung Hwa Ryu ),( Hee Sung Go ),( Seung Jung Kim ),( Duk Hee Kang ),( Dong Ryeol Ryu ),( Kyu Bok Choi ) 대한내과학회 2014 대한내과학회 추계학술발표논문집 Vol.2014 No.1
Background: Hyperphosphatemia is important problem because of its affect on endothelial dysfunction as well as homeostasis of bone. Chronic kidney disease(CKD) patients tend to have higher serum phosphorus values than those in healthy population due to their positive balance of phosphorus in kidney. There are a few studies which reported that serum phosphorus level was correlated with endothelial function. Recently it has been reported the patients with higher serum phosphorus level revealed the more endothelial dysfunction in healthy population. Thus, the following study was carried out in an effort to redefi ne the relationship between serum phosphorus level and endothelial dysfunction to those on chronic kidney disease. Methods: This is a cross-sectional study and the enrolled 79 CKD patients with exception of CKD stage 5 or receiving renal replacement therapy. They were subjected to the measurement with iontophoresis, and endoPAT, ankle brachial index, which represented endothelial function assessment. And also the average serum phosphrous level in patients was measured for the last three months including examination month. The Pearson`s correlation coeffi cient analysis was performed to defi ne the association of serum phosphorus and endothelial function. Results: When participants were divided into four groups according to estimated GFR, serum phosphorus level had signifi cant higher values in CKD stage 4. From univariate analysis, higher phosphorus level was associated with better endoPAT values(r=0.296, p=0.008). Multivariate analysis adjusted by PTH, TG showed significant correlation between the serum phophorus level and endoPAT. Conclusions: This study showed that serum phosphorus level may associate with endothelial function even in CKD. Furthermore, it is required a prospective study of larger population to identify the relationship between phosphorus and endothelial function and to establish optimal reference range of phosphorus level for protection from endothelial dysfunction.