Publications by authors named "Hyun Joo Yoo"

8 Publications

  • Page 1 of 1

Cortical thickness and resting-state cardiac function across the lifespan: A cross-sectional pooled mega-analysis.

Psychophysiology 2020 Oct 10. Epub 2020 Oct 10.

Norwegian Centre for Mental Disorders Research (NORMENT), Institute of Clinical Medicine, University of Oslo, Oslo, Norway.

Understanding the association between autonomic nervous system [ANS] function and brain morphology across the lifespan provides important insights into neurovisceral mechanisms underlying health and disease. Resting-state ANS activity, indexed by measures of heart rate [HR] and its variability [HRV] has been associated with brain morphology, particularly cortical thickness [CT]. While findings have been mixed regarding the anatomical distribution and direction of the associations, these inconsistencies may be due to sex and age differences in HR/HRV and CT. Previous studies have been limited by small sample sizes, which impede the assessment of sex differences and aging effects on the association between ANS function and CT. To overcome these limitations, 20 groups worldwide contributed data collected under similar protocols of CT assessment and HR/HRV recording to be pooled in a mega-analysis (N = 1,218 (50.5% female), mean age 36.7 years (range: 12-87)). Findings suggest a decline in HRV as well as CT with increasing age. CT, particularly in the orbitofrontal cortex, explained additional variance in HRV, beyond the effects of aging. This pattern of results may suggest that the decline in HRV with increasing age is related to a decline in orbitofrontal CT. These effects were independent of sex and specific to HRV; with no significant association between CT and HR. Greater CT across the adult lifespan may be vital for the maintenance of healthy cardiac regulation via the ANS-or greater cardiac vagal activity as indirectly reflected in HRV may slow brain atrophy. Findings reveal an important association between CT and cardiac parasympathetic activity with implications for healthy aging and longevity that should be studied further in longitudinal research.
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http://dx.doi.org/10.1111/psyp.13688DOI Listing
October 2020

Role of COX2 as a Biomarker for Estimating Survival of Patients With Clinical Stage I Gastric Cancer.

Anticancer Res 2020 Jan;40(1):341-347

Department of Surgery, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.

Background/aim: The prognostic significance of biomarkers related to gastric cancer prognosis has not been fully elucidated. The aim of study was to use immunohistochemical biomarkers to reveal prognosis.

Patients And Methods: A total of 682 patients who had undergone curative surgery were evaluated regarding the correlation of prognosis and immunohistochemical biomarkers.

Results: The COX2-positive groups showed a poor 5-year overall and disease-free survival. Further analysis revealed that COX2 positivity was a significant risk factor for poorer disease-free survival in the group with clinical stage I disease (p=0.016). We also noted a marked trend between COX2 positivity and poorer overall survival. The COX2-positive group showed general postoperative pathological up-staging compared with the COX2-negative group.

Conclusion: This study showed the potential of COX2 as a biomarker for gastric cancer prognosis. Preoperative evaluation of COX2 might be a useful tool for generating optimal treatment strategies in patients with clinical stage I gastric cancer.
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http://dx.doi.org/10.21873/anticanres.13958DOI Listing
January 2020

Is there any different risk factor for clinical relevant pancreatic fistula according to the stump closure method following left-sided pancreatectomy?

Ann Hepatobiliary Pancreat Surg 2019 Nov 29;23(4):385-391. Epub 2019 Nov 29.

Department of Surgery, Yeouido St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.

Backgrounds/aims: Consistency on risk factors for postoperative pancreatic fistula (POPF) after left-sided pancreatectomy (LP) according to the stump closure methods has not been revealed. Appropriate surgical stump closure method after LP is still in debate. This study investigates risk factors for POPF according to the closure methods in LP.

Methods: A total of 49 consecutive patients underwent LP with a stapler closure (ST) or hand-sewn closure (HS) between June 2001 and September 2016. The risk factors of pancreatic fistulas were investigated in 49 LPs according to stump closure methods, HS (n=19), and ST (n=30).

Results: There was no significant difference in the incidence of overall POPF (HS 42.1% vs. ST 50.0%) and clinical relevant POPF (CR-POPF) (HS 5.3% vs. ST 6.7%) between two groups. In the ST group, the pancreas was significantly thick in patients with CR-POPF (27 mm vs. 17 mm) and the tumor was also larger (58 mm vs. 27 mm). In the HS group, the operation time was longer in CR-POPF group (515 min vs 292 min). In univariate analysis, wider diameter of the pancreatic duct (27 mm vs 16 mm) was associated with POPF in the HS group. There was no meaningful risk factor for POPF in the ST group.

Conclusions: Incidence of overall POPF between the ST and HS group were clinically insignificant in this study. The thickness of the pancreas and the tumor diameter are factors significantly associated with CR-POPF in the ST group. Long operation time was the only factor associated with CR-POPF in the HS group.
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http://dx.doi.org/10.14701/ahbps.2019.23.4.385DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6893043PMC
November 2019

Brain structural concomitants of resting state heart rate variability in the young and old: evidence from two independent samples.

Brain Struct Funct 2018 Mar 18;223(2):727-737. Epub 2017 Sep 18.

Department of Psychology, The Ohio State University, Columbus, OH, USA.

Previous research has shown associations between brain structure and resting state high-frequency heart rate variability (HF HRV). Age affects both brain structure and HF HRV. Therefore, we sought to examine the relationship between brain structure and HF HRV as a function of age. Data from two independent studies were used for the present analysis. Study 1 included 19 older adults (10 males, age range 62-78 years) and 19 younger adults (12 males, age range 19-37). Study 2 included 23 older adults (12 males; age range 55-75) and 27 younger adults (17 males; age range 18-34). The root-mean-square of successive R-R-interval differences (RMSSD) from ECG recordings was used as time-domain measure of HF HRV. MRI scans were performed on a 3.0-T Siemens Magnetom Trio scanner. Cortical reconstruction and volumetric segmentation were performed with the Freesurfer image analysis suite, including 12 regions as regions of interests (ROI). Zero-order and partial correlations were used to assess the correlation of RMSSD with cortical thickness in selected ROIs. Lateral orbitofrontal cortex (OFC) cortical thickness was significantly associated with RMSSD. Further, both studies, in line with previous research, showed correlations between RMSSD and anterior cingulate cortex (ACC) cortical thickness. Meta-analysis on adjusted correlation coefficients from individual studies confirmed an association of RMSSD with the left rostral ACC and the left lateral OFC. Future longitudinal studies are necessary to trace individual trajectories in the association of HRV and brain structure across aging.
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http://dx.doi.org/10.1007/s00429-017-1519-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5828882PMC
March 2018

Adipocyte-Specific Deficiency of De Novo Sphingolipid Biosynthesis Leads to Lipodystrophy and Insulin Resistance.

Diabetes 2017 10 11;66(10):2596-2609. Epub 2017 Jul 11.

Department of Life Science, Gachon University, Sungnam, Korea

Sphingolipids have been implicated in the etiology of chronic metabolic diseases. Here, we investigated whether sphingolipid biosynthesis is associated with the development of adipose tissues and metabolic diseases. SPTLC2, a subunit of serine palmitoyltransferase, was transcriptionally upregulated in the adipose tissues of obese mice and in differentiating adipocytes. Adipocyte-specific SPTLC2-deficient (aSPTLC2 KO) mice had markedly reduced adipose tissue mass. Fatty acids that were destined for the adipose tissue were instead shunted to liver and caused hepatosteatosis. This impaired fat distribution caused systemic insulin resistance and hyperglycemia, indicating severe lipodystrophy. Mechanistically, sphingosine 1-phosphate (S1P) was reduced in the adipose tissues of aSPTLC2 KO mice, and this inhibited adipocyte proliferation and differentiation via the downregulation of S1P receptor 1 and decreased activity of the peroxisome proliferator-activator receptor γ. In addition, downregulation of SREBP (sterol regulatory element-binding protein)-1c prevented adipogenesis of aSPTLC2 KO adipocytes. Collectively, our observations suggest that the tight regulation of de novo sphingolipid biosynthesis and S1P signaling plays an important role in adipogenesis and hepatosteatosis.
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http://dx.doi.org/10.2337/db16-1232DOI Listing
October 2017

Higher locus coeruleus MRI contrast is associated with lower parasympathetic influence over heart rate variability.

Neuroimage 2017 04 17;150:329-335. Epub 2017 Feb 17.

Department of Psychology, The Ohio State University, Columbus, OH, USA.

The locus coeruleus (LC) is a key node of the sympathetic nervous system and suppresses parasympathetic activity that would otherwise increase heart rate variability. In the current study, we examined whether LC-MRI contrast reflecting neuromelanin accumulation in the LC was associated with high-frequency heart rate variability (HF-HRV), a measure reflecting parasympathetic influences on the heart. Recent evidence indicates that neuromelanin, a byproduct of catecholamine metabolism, accumulates in the LC through young and mid adulthood, suggesting that LC-MRI contrast may be a useful biomarker of individual differences in habitual LC activation. We found that, across younger and older adults, greater LC-MRI contrast was negatively associated with HF-HRV during fear conditioning and spatial detection tasks. This correlation was not accounted for by individual differences in age or anxiety. These findings indicate that individual differences in LC structure relate to key cardiovascular parameters.
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http://dx.doi.org/10.1016/j.neuroimage.2017.02.025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5391255PMC
April 2017

Heart rate variability is associated with amygdala functional connectivity with MPFC across younger and older adults.

Neuroimage 2016 Oct 31;139:44-52. Epub 2016 May 31.

University of Southern California, United States.

The ability to regulate emotion is crucial to promote well-being. Evidence suggests that the medial prefrontal cortex (mPFC) and adjacent anterior cingulate (ACC) modulate amygdala activity during emotion regulation. Yet less is known about whether the amygdala-mPFC circuit is linked with regulation of the autonomic nervous system and whether the relationship differs across the adult lifespan. The current study tested the hypothesis that heart rate variability (HRV) reflects the strength of mPFC-amygdala interaction across younger and older adults. We recorded participants' heart rates at baseline and examined whether baseline HRV was associated with amygdala-mPFC functional connectivity during rest. We found that higher HRV was associated with stronger functional connectivity between the amygdala and the mPFC during rest across younger and older adults. In addition to this age-invariant pattern, there was an age-related change, such that greater HRV was linked with stronger functional connectivity between amygdala and ventrolateral PFC (vlPFC) in younger than in older adults. These results are in line with past evidence that vlPFC is involved in emotion regulation especially in younger adults. Taken together, our results support the neurovisceral integration model and suggest that higher heart rate variability is associated with neural mechanisms that support successful emotional regulation across the adult lifespan.
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http://dx.doi.org/10.1016/j.neuroimage.2016.05.076DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5133191PMC
October 2016

RANKL-induced schlafen2 is a positive regulator of osteoclastogenesis.

Cell Signal 2008 Dec 31;20(12):2302-8. Epub 2008 Aug 31.

Division of Life and Pharmaceutical Sciences, Center for Cell Signaling and Drug Discovery Research, Ewha Womans University, Seoul 120-750, Republic of Korea.

Osteoclasts are hematopoietic lineage derived-multinucleated cells that resorb bone. Their activity in balance with that of osteoblast is essential for bone homeostasis. Receptor activator of NF-kappaB ligand (RANKL) is known as an essential cytokine for the osteoclastogenesis, and c-Jun signaling in cooperation with NFAT family is crucial for RANKL-regulated osteoclastogenesis. We show here that schlafen2 (Slfn2), a member of a new family of growth regulatory genes involved in thymocyte development, is critical for osteoclastogenesis. RANKL selectively induces Slfn2 expression in osteoclast precursors via Rac1 signaling pathway. Targeted inhibition of Slfn2 by small interfering RNAs (siRNAs) markedly inhibits the formation of osteoclasts by diminishing the activation of c-Jun and the expression of c-Jun and NFATc1. In contrast, the overexpression of Slfn2 markedly increased phosphorylation and transactivation of c-Jun by RANKL. Together, these results indicate that Slfn2 has an essential role in osteoclastogenesis, functioning upstream of c-Jun and NFATc1.
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http://dx.doi.org/10.1016/j.cellsig.2008.08.019DOI Listing
December 2008