Publications by authors named "Geon Park"

79 Publications

Performance assessment of ASTA MicroIDSys, a new matrix assisted laser desorption ionization-time of flight mass spectrometry system, for identification of viridans group streptococci.

Microbiol Immunol 2021 Sep 13. Epub 2021 Sep 13.

Department of Laboratory Medicine, School of Medicine, Chosun University, Gwangju, Republic of Korea.

The performance of the ASTA MicroIDSys system (ASTA), a new matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) system, was evaluated for the identification of viridans group streptococci (VGS) and compared with the results obtained with the Bruker Biotyper system (Bruker Daltonics). A total of 106 Streptococcus reference strains belonging to 24 species from the bacterial strain bank was analyzed using the two MALDI-TOF MS systems. Of the 106 reference strains tested, ASTA MicroIDSys and Bruker Biotyper correctly identified 84.9% and 81.1% at the species level, 100% and 97.2% at the group level and 100% and 98.1% at the genus level, respectively. The difference between the two systems was not statistically significant (P = 0.289). Out of 24 species, 13 species were accurately identified to the species level with 100% accurate identification rates with both systems. The accurate identification rates at the species level of ASTA MicroIDSys and Bruker Biotyper were 100% and 87.5% for the S. anginosus group; 78.4% and 73.5% for the S. mitis group; 91.7% and 91.7% for the S. mutans group; and 100% and 100% for the S. salivarius group, respectively. The ASTA MicroIDSys showed an identification performance equivalent to that of the Bruker Biotyper for VGS. Therefore, it would be useful for the identification of VGS strains in clinical microbiology laboratories.
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http://dx.doi.org/10.1111/1348-0421.12942DOI Listing
September 2021

Relationships between Relative Expression of RND Efflux Pump Genes, H33342 Efflux Activity, Biofilm-Forming Activity, and Antimicrobial Resistance in Acinetobacter baumannii Clinical Isolates.

Jpn J Infect Dis 2021 Nov 26;74(6):499-506. Epub 2021 Feb 26.

Department of Laboratory Medicine, College of Medicine, Chosun University, Republic of Korea.

Various mechanisms underlying antimicrobial resistance in Acinetobacter baumannii have been reported. However, the relationships between efflux pump activity, biofilm formation, and antimicrobial resistance in A. baumannii is controversial. In this study, we investigated the relative expression of RND efflux pump genes, H33342 efflux activity, and biofilm-forming activity in 120 A. baumannii clinical isolates, examined their potential relationships with each other, and statistically analyzed their effects on antibiotic resistance. High adeB expression and high H33342 efflux activity were correlated with low biofilm-forming activity. High adeB expression was significantly correlated with resistance to tigecycline and cefotaxime, but not with the multidrug resistance (MDR) phenotype. Importantly, only high adeJ expression was significantly correlated with the MDR phenotype and was correlated with resistance to various antibiotics. However, we found no significant correlation between adeJ expression and biofilm-forming activity. Furthermore, adeG expression was not correlated with antibiotic resistance and biofilm-forming activity. The results of multivariate analysis showed that adeB overexpression and high H33342 efflux activity were related to biofilm-forming activity, and only adeJ overexpression was significantly associated with the MDR phenotype, highlighting the importance of adeJ overexpression.
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http://dx.doi.org/10.7883/yoken.JJID.2020.765DOI Listing
November 2021

Association of Vitamin D Status with Lower Limb Muscle Strength in Professional Basketball Players: A Cross-Sectional Study.

Nutrients 2020 Sep 5;12(9). Epub 2020 Sep 5.

Department of Sports Medicine Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 03063, Korea.

Vitamin D deficiency in athletes may play a role in influencing fracture risk and athletic performance. This study aimed to examine the vitamin D status of basketball players and determine its correlation with muscle strength. We included 36 male professional basketball players (mean age, 22.6 ± 3.2 years) categorized by vitamin D status. We examined the muscle strength of knee extension/flexion and ankle dorsiflexion/plantarflexion using an isokinetic dynamometer. Eleven (30.5%), fifteen (41.7%), and ten (27.8%) players had deficient (<20 ng/mL), insufficient (20-32 ng/mL), and sufficient vitamin D levels (>32 ng/mL), respectively. In the dominant side, there were no significant correlations of vitamin D level with knee extension/flexion strength ( = 0.134, = 0.436; = -0.017, = 0.922, respectively), or with plantarflexion/dorsiflexion ankle strength ( = -0.143, = 0.404; = 1.109, = 0.527, respectively). Moreover, the isokinetic lower limb strengths were not significantly different between the three groups in all settings (all > 0.05). In conclusion, professional basketball players had a high prevalence of vitamin D insufficiency. Though it may not be associated with muscle strength, maintaining adequate vitamin D levels by micronutrients monitoring, regular dietician consultation, and supplementation is still a critically considerable strategy to enhance young athletes' health.
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http://dx.doi.org/10.3390/nu12092715DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7551193PMC
September 2020

Isokinetic Performance of Shoulder External and Internal Rotators of Professional Volleyball Athletes by Different Positions.

Sci Rep 2020 05 26;10(1):8706. Epub 2020 May 26.

Department of Sports Medicine Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.

This study aimed to exam the isokinetic shoulder rotator strength of professional volleyball athletes, by playing positions. This cross-sectional study included a total of 49 healthy male professional volleyball players. We measured the isokinetic strength of the external rotator (ER) and internal rotator (IR) muscles and compared the dominant and non-dominant shoulders at angular speeds of 60°/s and 180°/s. In ER, all positions of players had similar strength between the dominant shoulder and non-dominant shoulders. Conversely, all playing positions except libero had stronger strength in dominant shoulder than that in the non-dominant shoulder. The ER/IR ratio in the dominant shoulder was significantly lower only for the attacker (outside hitter and opposite) at 60°/s and 180°/s (P < 0.0001; P = 0.0028 respectively) and blocker at 60°/s (P = 0.0273) when compared with non-dominant shoulder. Furthermore, the attacker had a lower ER/IR ratio in the dominant shoulder than setter and libero at 60°/s and 180°/s. For elite volleyball players without injury, the dominant shoulder had a higher strength of internal rotation, causing the relative muscle imbalance than the non-dominant shoulder, especially for the attacker and blocker positions. Training program should be individualized for each playing position to improve the imbalanced shoulder.
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http://dx.doi.org/10.1038/s41598-020-65630-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7251108PMC
May 2020

Anterior Cruciate Ligament Reconstruction in Patients Older Than 50 Years: A Systematic Review and Meta-analysis.

Orthop J Sports Med 2020 Apr 29;8(4):2325967120915698. Epub 2020 Apr 29.

School of Medicine, Samsung Medical Center, Sungkyunkwan University, Seoul, Republic of Korea.

Background: There is no consensus regarding the best treatment approach for middle-aged patients with anterior cruciate ligament (ACL) injuries. Chronic ACL-deficient knees are often associated with instability as well as secondary meniscal and cartilage lesions. ACL reconstruction (ACLR) has achieved satisfactory outcomes in younger patients; however, the effectiveness and safety of ACLR in middle-aged patients remain uncertain.

Purpose: To compare the patient-reported functional scores, arthrometric outcomes, and complications of primary ACLR between older (≥50 years) and younger (<50 years) patients.

Study Design: Systematic review; Level of evidence, 3.

Methods: We conducted a systematic review of cohort studies that compared the clinical outcomes of ACLR between patients aged ≥50 years and those aged <50 years. The Cochrane Central Register of Controlled Trials, Embase, and MEDLINE databases were searched for relevant studies. The Methodological Index for Non-randomized Studies (MINORS) criteria was used to assess the risk of bias and conducted a random-effects meta-analysis to combine the data, and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to evaluate the overall quality of the body of retrieved evidence. The primary outcome was knee functional outcomes, and secondary outcomes were arthrometric outcomes of ACLR and complications.

Results: This study included 4 retrospective cohort studies with a total of 287 participants (129 in the older group and 158 in the younger group). All included studies reported significant improvements in clinical outcomes in both groups after ACLR. No significant differences were noted in the improvement of International Knee Documentation Committee (IKDC) scores (mean difference [MD], 0.20 [95% CI, -2.65 to 3.05]; = .89) and Lysholm scores (MD, -1.98 [95% CI, -6.93 to 2.98]; = .43) between the 2 groups. No significant differences were observed in anteroposterior stability or risk of complications between the groups.

Conclusion: ACLR may be performed in middle-aged patients (≥50 years) without concern for inferior clinical and arthrometric results compared with younger patients (<50 years).
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http://dx.doi.org/10.1177/2325967120915698DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7218932PMC
April 2020

Mechanical intestinal obstruction following laparoscopic inguinal hernia repair in a patient with abdominal cocoon syndrome.

J Surg Case Rep 2019 Dec 17;2019(12):rjz370. Epub 2019 Dec 17.

Department of Surgery, Pusan National University Hospital, Busan 49241, Korea.

Abdominal cocoon syndrome (ACS) is a rare condition characterized by partial or complete encasement of small intestine by a thick fibro-collagenous membrane. A 65-year-old man presented to the surgical department with left inguinal. He underwent laparoscopic transabdominal preperitoneal inguinal hernia. When we inserted a trocar into the peritoneal cavity, the small intestine was injured and repaired immediately. We identified a fibrotic membrane covering the small intestine, which was found as ACS. Two weeks later after discharge, he presented to the emergency department with mechanical intestinal obstruction. Conservative treatment had no effect on the patient and membrane excision, adhesiolysis and small intestine resection with anastomosis were performed. Unfortunately, the patient was hospitalized for a long time with bowel leakage and discharged on postoperative day 48. The preoperative diagnosis is quite challenging and most cases are diagnosed intraoperatively. When finding the ACS during the operation, careful attention should be needed.
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http://dx.doi.org/10.1093/jscr/rjz370DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6917468PMC
December 2019

Task complexity interacts with state-space uncertainty in the arbitration between model-based and model-free learning.

Nat Commun 2019 12 16;10(1):5738. Epub 2019 Dec 16.

Department of Bio and Brain Engineering, Korea Advanced Institute of Science Technology (KAIST), Daejeon, 34141, Republic of Korea.

It has previously been shown that the relative reliability of model-based and model-free reinforcement-learning (RL) systems plays a role in the allocation of behavioral control between them. However, the role of task complexity in the arbitration between these two strategies remains largely unknown. Here, using a combination of novel task design, computational modelling, and model-based fMRI analysis, we examined the role of task complexity alongside state-space uncertainty in the arbitration process. Participants tended to increase model-based RL control in response to increasing task complexity. However, they resorted to model-free RL when both uncertainty and task complexity were high, suggesting that these two variables interact during the arbitration process. Computational fMRI revealed that task complexity interacts with neural representations of the reliability of the two systems in the inferior prefrontal cortex.
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http://dx.doi.org/10.1038/s41467-019-13632-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6915739PMC
December 2019

The Relationship between Vitamin D Status and Rotator Cuff Muscle Strength in Professional Volleyball Athletes.

Nutrients 2019 Nov 14;11(11). Epub 2019 Nov 14.

Department of Sports Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 03063, Korea.

This study aimed to examine the vitamin D status of professional volleyball athletes and to determine its correlation with shoulder muscle strength. We included 52 healthy male professional volleyball players (23.2 ± 4.5 years), who were categorized by vitamin D status (<20 ng/mL: deficiency, 20-30 ng/mL: insufficiency, and >30 ng/mL: sufficiency). We examined the strength of the internal rotator (IR) and external rotator (ER) muscles of the shoulder by using an isokinetic dynamometer. Fourteen players (26.9%) had vitamin D deficiency, 24 players (46.2%) were vitamin D-insufficient, and 14 players (26.9%) were vitamin D-sufficient. There was no significant correlation between vitamin D level and shoulder muscle strength at 60°/s (IR, = 0.159, = 0.26; ER, = 0.245, = 0.08) and at 180°/s (IR, = -0.093, = 0.51; ER, = -0.037, = 0.79). Moreover, the isokinetic shoulder strengths were not significantly different across the three groups in all settings. In conclusion, vitamin D insufficiency was common in elite volleyball players. Though not being associated with isokinetic muscle weakness, vitamin D levels should be regularly monitored, and vitamin D should be supplied to young elite athletes, considering its importance for musculoskeletal health.
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http://dx.doi.org/10.3390/nu11112768DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6893407PMC
November 2019

Rapid and Reliable One-Step Genotyping Using Direct Real-Time Allele-Specific PCR and Melting Curve Analysis Without DNA Preparation.

Indian J Hematol Blood Transfus 2019 Jul 18;35(3):531-537. Epub 2018 Dec 18.

2Department of Laboratory Medicine, Chosun University College of Medicine, 365 Pilmun-daero, Dong-gu, Gwangju, 61453 South Korea.

genotyping is a molecular diagnostic technique important for transfusion and transplantation in medicine, and human identification in forensic science. Because genotyping are labor intensive and time consuming, the genotyping cannot be firstly used to resolve the serological ABO discrepancy in blood bank. For rapid one-step genotyping, we developed direct, real-time, allele-specific polymerase chain reaction (PCR), and melting curve analysis (DRAM assay) without DNA preparation. In DRAM assay, we used a special PCR buffer for direct PCR, a rapid RBC lysis buffer, white blood cells as template without DNA preparation, allele-specific primers for discriminating three alleles (261G/del, 796C/A, and 803G/C), and melting curve analysis as a detection method. There was 100% concordance among the results of genotyping by the DRAM assay, serologic typing, PCR-RFLP and PCR-direct sequencing of 96 venous blood samples. We were able to reduce the number of manual steps to three and the hands-on time to 12 min, compared to seven steps and approximately 40 min for conventional genotyping using allele-specific PCR with purified DNA and agarose gel electrophoresis. We have established and validated the DRAM assay for rapid and reliable one-step genotyping in a closed system. The DRAM assay with an appropriate number of allele-specific primers could help in resolving ABO discrepancies and should be valuable in clinical laboratory and blood bank.
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http://dx.doi.org/10.1007/s12288-018-1053-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6646450PMC
July 2019

A rare collision tumor comprising intracystic papillary neoplasm associated with adenocarcinoma and angiosarcoma in the gallbladder.

Korean J Intern Med 2020 05 31;35(3):732-733. Epub 2019 Jul 31.

Department of Pathology, College of Medicine, Daejeon St. Mary's Hospital, The Catholic University of Korea, Daejeon, Korea.

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http://dx.doi.org/10.3904/kjim.2018.394DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7214352PMC
May 2020

Patients older than 50 years had similar results of knee strength and anteroposterior stability after ACL reconstruction compared to younger patients.

Knee Surg Sports Traumatol Arthrosc 2019 Jan 2;27(1):230-238. Epub 2019 Jan 2.

Department of Sports Medicine Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul, 135-710, South Korea.

Purpose: To evaluate knee strength, ligament stability, and functional outcomes in patients older than 50 years who underwent anterior cruciate ligament (ACL) reconstruction, and to compare these results with those obtained from a younger patient group (< 40 years).

Methods: Forty patients older than 50 years and 50 patients younger than 40 years who underwent ACL reconstruction were retrospectively studied. Isokinetic extensor and flexor muscle strength were evaluated. The peak torque was determined at speeds of 60°/s and 180°/s. The highest peak torque at each velocity was compared with that on the uninjured side. Patients were also evaluated for knee anteroposterior (AP) laxity and functional outcomes, which were measured by the Lysholm and International Knee Documentation Committee (IKDC) scores. All tests were evaluated at baseline and 1 year postoperatively.

Results: The groups were comparable at the baseline. Both groups had significant improvements in all parameters, including isokinetic muscle strength, AP laxity, and functional scores, at 1 year postoperatively (all p < 0.05). Compared with younger patients, older patients had similar results for extensor and flexor strength, AP laxity, and Lysholm score (n.s.). However, younger patients had better IKDC scores than did older patients [median 81.1; 95% confidence interval (CI) 95% CI 78.9-88.7 vs. median 75.6; 95% CI 70.1-79.3, p = 0.007].

Conclusions: Though with lower IKDC scores, older patients with ACL reconstruction had comparable results of knee strength and ligament laxity to younger patients. ACL reconstruction is recommended for treating patients older than 50 years with ACL insufficiency, especially for those with high functional demand.

Level Of Evidence: Retrospective cohort study, III.
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http://dx.doi.org/10.1007/s00167-018-5342-3DOI Listing
January 2019

The effects of pain on quadriceps strength, joint proprioception and dynamic balance among women aged 65 to 75 years with knee osteoarthritis.

BMC Geriatr 2018 10 17;18(1):245. Epub 2018 Oct 17.

Department of Sports Medicine Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul, 135-710, South Korea.

Background: Patients with knee osteoarthritis (OA) were reported to have quadriceps weakness, and impaired proprioception, both related to pain and swelling. It is unclear whether pain alone a causal factor to above findings over the knee joint. The purpose of this study was to assess the effects of knee pain alone on the quadriceps strength, proprioception and dynamic balance in subjects with bilateral knee OA without joint swelling.

Methods: Fourty females with mean age of 68.3 years were involved in this cross-sectional study. The inclusion criteria were bilateral knee OA without joint swelling, with a visual analogue pain scale difference (> 1) between each knee. Patients all underwent assessment of the isokinetic strength of knee muscles, knee proprioceptive acuity, and dynamic balance.

Results: Patients' more painful knee had weaker isokinetic quadriceps strength than less painful knee at both 60 °/s and 180 °/s (p = 0.01, p = 0.01, respectively). There were no differences in proprioceptive acuity between both knees in all three knee positions. Meanwhile, there was a significant difference in the dynamic balance index measurement between both knees (more painful versus less painful: 3.88 ± 1.15 vs. 3.30 ± 1.00, p = 0.01). Quadriceps strength was associated with dynamic balance stability (60 °/s, r = - 0.578, p <  0.01; 180 °/s, r = - 0.439, p <  0.01).

Conclusions: For patients with knee OA, the more painful knee was associated with weaker quadriceps and poor balance ability. To improve lower limb function and balance stability of the older persons having knee OA, physicians should take the optimal pain management strategy.
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http://dx.doi.org/10.1186/s12877-018-0932-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6192068PMC
October 2018

Rapid, Reliable, and Inexpensive Detection Method Using DNA Binding Dye-based Duplex Allele-specific Melting Curve Analysis.

Ann Clin Lab Sci 2018 May;48(3):296-300

Department of Laboratory Medicine, Chosun University College of Medicine, Gwangju, Korea

Background: Allopurinol is the most commonly used drug for the treatment of gout and also one of the most common causes of severe cutaneous adverse reactions (SCARs). Human leukocyte antigen- is strongly associated with allopurinol-induced SCARs. The aim of the present study was to develop and validate a rapid and economic screening method for .

Methods: The accuracy of duplex allele-specific melting curve analysis using DNA-binding dye for was evaluated in 150 blood samples with sequence-based typing (SBT) as the reference method.

Results: Fifty -positive and 100 negative results obtained by duplex allele-specific melting curve analysis were completely in agreement with the SBT results.

Conclusion: Duplex allele-specific melting curve analysis is a rapid, reliable and inexpensive assay that is appropriate for screening for the allele.
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May 2018

Correction: Necrosis-inducing peptide has the beneficial effect on killing tumor cells through neuropilin (NRP-1) targeting.

Oncotarget 2018 06 1;9(42):26977. Epub 2018 Jun 1.

Department of Biochemistry, Chosun University School of Medicine, Dong-Gu, Gwang-Ju, Korea.

[This corrects the article DOI: 10.18632/oncotarget.8719.].
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http://dx.doi.org/10.18632/oncotarget.25604DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6003566PMC
June 2018

Comparison of Knee Stability, Strength Deficits, and Functional Score in Primary and Revision Anterior Cruciate Ligament Reconstructed Knees.

Sci Rep 2018 06 15;8(1):9186. Epub 2018 Jun 15.

Department of Sports Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.

Comparing to primary surgery, revision ACL reconstruction is more technically demanding and has a higher failure rate. Theoretically, rehabilitation can improve knee function after ACL reconstruction surgery. This study aimed to compare knee stability, strength, and function between primary and revision ACL reconstructed knees. 40 primary and 40 revision ACL reconstruction surgeries were included between April 2013 and May 2016. Patients with revision surgery had a higher anteroposterior translation comparing those with primary reconstruction (median laxity, 2.0 mm vs. 3.0 mm, p = 0.0022). No differences were noted in knee extensor at 60°/sec or 180°/sec (p = 0.308, p = 0.931, respectively) or in flexor muscle strength at 60°/sec or 180°/sec between primary and revision ACL reconstruction knees (p = 0.091, p = 0.343, respectively). There were also no significant differences between functional scores including IKDC score and Lysholm score in primary versus revision surgeries at 12th months after index operation (p = 0.154, p = 0.324, respectively). In conclusion, despite having higher anteroposterior instability, patients with revision ACL reconstruction can have non-inferior outcomes in isokinetic knee strength and function compared to those with primary ACL reconstruction after proper rehabilitation.
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http://dx.doi.org/10.1038/s41598-018-27595-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6003945PMC
June 2018

Bilateral perirenal extra-adrenal myelolipoma in a haemodialysis patient.

Nephrology (Carlton) 2018 06;23(6):604-605

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

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http://dx.doi.org/10.1111/nep.13136DOI Listing
June 2018

Clinical Etiology of Hypermetabolic Pelvic Lesions in Postoperative Positron Emission Tomography/Computed Tomography for Patients With Rectal and Sigmoid Cancer.

Ann Coloproctol 2018 Apr 30;34(2):78-82. Epub 2018 Apr 30.

Department of Radiology, The Catholic University of Korea, Daejeon St. Mary's Hospital, Daejeon, Korea.

Purpose: The purpose of this study was to present various clinical etiologies of hypermetabolic pelvic lesions on postoperative positron emission tomography/computed tomography (PET/CT) images for patients with rectal and sigmoid cancer.

Methods: Postoperative PET/CT images for patients with rectal and sigmoid cancer were retrospectively reviewed to identify hypermetabolic pelvic lesions. Positive findings were detected in 70 PET/CT images from 45 patients; 2 patients who were lost to follow-up were excluded. All PET findings were analyzed in comparison with contrast-enhanced CT.

Results: A total of 43 patients were classified into 2 groups: patients with a malignancy including local recurrence (n = 30) and patients with other benign lesions (n = 13). Malignant lesions such as a local recurrent tumor, peritoneal carcinomatosis, and incidental uterine malignancy, as well as various benign lesions such as an anastomotic sinus, fistula, abscess, reactive lymph node, and normal ovary, were observed.

Conclusion: PET/CT performed during postoperative surveillance of rectal and sigmoid colon cancer showed increased fluorodeoxyglucose uptake not only in local recurrence, but also in benign pelvic etiologies. Therefore, physicians need to be cautious about the broad clinical spectrum of hypermetabolic pelvic lesions when interpreting images.
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http://dx.doi.org/10.3393/ac.2017.09.21DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5951092PMC
April 2018

The synonymous nucleotide substitution RHD 1056C>G alters mRNA splicing associated with serologically weak D phenotype.

J Clin Lab Anal 2018 May 19;32(4):e22330. Epub 2017 Sep 19.

Department of Laboratory Medicine & Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.

Background: D antigen is one of the most clinically significant blood group antigens. Variation of the RHD gene can cause weak D or partial D phenotypes. While most variations are missense substitutions with amino acid changes, those without are called "silent" or "synonymous" substitutions. Synonymous substitutions often have little effect on the protein, not altering the phenotype. However, effect on splicing can affect end-product protein. We report a new synonymous variation, RHD 1056C>G, that resulted in weak D phenotype, and predicted its effect with various in silico methods.

Methods: Serologic testing of the D antigen with full sequencing of the RHD gene was done. Human Splice Finder was used to predict the effect of this variation, and validation of this method was done with all known RHD variations reported in the literature.

Results: RHD 1056C>G was predicted to cause the formation of an exonic splicing silencer (ESS) site. The creation of new ESS site potentially inhibits the splicing event, resulting alteration of splicing. This is similar to remodeling of splice acceptor or donor site, as this kind of deep exonic variation could affect the D antigen's quality or quantity. This is in concordance with serologic results, which showed only delayed weak agglutination to anti-D reagents.

Conclusions: The analytic methods we applied showed good correlation with the actual phenotype, along with concordant results when analyzing other known variants reported in the literature. We conclude that RHD 1056C>G results in serologic weak D phenotype.
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http://dx.doi.org/10.1002/jcla.22330DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6817278PMC
May 2018

Stroke or left atrial thrombus prediction using antithrombin III and mean platelet volume in patients with nonvalvular atrial fibrillation.

Clin Cardiol 2017 Nov 14;40(11):1013-1019. Epub 2017 Aug 14.

Department of Internal Medicine, Chosun University School of Medicine, Gwangju, Republic of Korea.

Background: CHADS (congestive heart failure, hypertension, age ≥ 75 years, diabetes mellitus, stroke) and CHA DS -VASc (congestive heart failure, hypertension, age ≥ 75 years, diabetes mellitus, stroke, vascular disease, age 65 to 74 years, sex category) scores showed just moderate discrimination ability in predicting thromboembolic complications in patients with nonvalvular atrial fibrillation (AF).

Hypothesis: To determine the association of antithrombin III (AT-III) deficiency and mean platelet volume (MPV) with the development of stroke or left atrial (LA) thrombus in patients with AF.

Methods: AT-III and MPV were analyzed in 352 patients with AF. The primary endpoint was a composite of ischemic stroke event and incidental LA thrombus.

Results: There were 50 events (14.2%) during a mean 35.4 months of follow-up. A significantly higher stroke or LA thrombus rate was observed in the low-AT-III group (<70%) than that in the high-AT-III group (≥70%). A significantly higher stroke or LA thrombus rate was observed in the high-MPV group (≥7.0 fL) than that in the low-MPV group (<7.0 fL). AF patients with an MPV ≥7.0 fL and AT-III deficiency had higher stroke or LA thrombus risk than those without an MPV ≥7.0 fL and AT-III deficiency. In the Cox proportional hazard analysis, high MPV was found to be an independent predictor of stroke or LA thrombus risk (hazard ratio: 6.408; 95% confidence interval: 2.874-14.286). Although AT-III deficiency was not an independent predictor of stroke or LA thrombus risk, a trend was observed.

Conclusions: High MPV and AT-III deficiency were predictive markers for stroke or LA thrombus. Their predictive power for stroke was independent of antiplatelet treatment, anticoagulation therapy, and a high CHA DS -VASc score in patients with AF.
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http://dx.doi.org/10.1002/clc.22759DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6490604PMC
November 2017

Characteristics of 18F-fluorodeoxyglucose uptake in anastomotic sinus and fistula following rectal cancer surgery.

Clin Imaging 2017 Jan - Feb;41:33-36. Epub 2016 Aug 26.

Department of Radiology, The Catholic University of Korea, Daejeon Saint Mary's Hospital, 64, Daeheung-ro, Jung-gu, Daejeon, 34943, Republic of Korea. Electronic address:

Purpose: To assess the characteristics of 18F-fluorodeoxyglucose (FDG) uptake in persisting anastomotic sinus and fistula following rectal cancer surgery.

Methods: Eight patients with anastomotic sinus and fistula were retrospectively studied.

Results: A total of 13 anastomotic sinuses (n=11) and fistulas (n=2) were observed. Sixteen FDG-positron emission tomography/computed tomography studies for 13 lesions performed and 26 uptake patterns were evaluated. Twenty-one lesions were found to have diffuse increased uptake, whereas four lesions had focal uptake. There was only one lesion without FDG uptake.

Conclusions: Increased FDG uptake is frequently observed in anastomotic sinus and fistula, which should be known to avoid making wrong diagnosis.
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http://dx.doi.org/10.1016/j.clinimag.2016.08.019DOI Listing
January 2017

A Novel FLCN c.1489_1490delTG Mutation that Escapes the Nonsense-Mediated Decay System.

Ann Clin Lab Sci 2016 Sep;46(5):562-5

Department of Laboratory Medicine, Chosun University College of Medicine, Gwangju, South Korea

A novel FLCN c.1489_1490delTG (p.Val497Glyfs*22) mutation at the genomic DNA and mRNA levels was identified in a 43-year-old woman with complaining of recurrent primary spontaneous pneumothorax. The aberrant FLCN mRNA escaped the nonsense-mediated decay system (NMD) because of a premature termination code located in an NMD-incompetent region. To the best of our knowledge, this is the first case report of an FLCN mutation escaping the NMD.
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September 2016

Cowden Syndrome Detected by FDG PET/CT in an Endometrial Cancer Patient.

Nucl Med Mol Imaging 2016 Sep 4;50(3):255-7. Epub 2016 Jun 4.

Department of Radiology, The Catholic University of Korea, Daejeon Saint Mary's Hospital, 64, Daeheung-ro, Jung-gu, Daejeon, 34943 Republic of Korea.

Cowden syndrome (CS) is a rare autosomal dominant disorder characterized by multiple hamartomas in various tissues and cancers (breast, thyroid, and endometrium). We report CS of the esophagus and gastrointestinal tract that was incidentally detected by positron emission tomography/computed tomography (PET/CT) at postoperative surveillance in an endometrial cancer patient. PET/CT showed mildly increased FDG uptake along the entire esophagus and stomach. Upper GI endoscopy and histologic examination revealed glycogenic acanthosis of the esophagus and several hundred gastric polyps. In our case, increased FDG uptake of the esophageal wall contributed to the diagnosis of CS.
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http://dx.doi.org/10.1007/s13139-016-0427-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4977259PMC
September 2016

Electrochemical Properties of Graphene Oxide/Resol Composites as Electrode Materials for Supercapacitor Applications.

J Nanosci Nanotechnol 2016 May;16(5):4320-7

RGO/Resol carbon composites were prepared from a mixture of reduced GO and a low-molecular-weight phenolic resin (Resol) solution. The effects of the calcination temperature, amount of Resol added and KOH treatment on the electrochemical performance of the RGO/Resol composites were investigated. The physical and electrochemical properties of the composite materials were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer, Emmett and Teller (BET) surface areas measurements, and cyclic voltammetry (CV). The relationships between their physical properties and their electrochemical performance were examined for use as super-capacitors (SCs). The RGO/Resol composite calcined at 400 degrees C after the KOH loading showed dramatically improved electrochemical properties, showing a high BET surface and capacitance of 2190 m2/g and 220 F/g, respectively. The RGO/Resol composites calcined after the KOH treatment showed much better capacitor performance than those treated only thermally at the same temperature without KOH impregnation. The fabrication of high surface electrodes was essential for improving the SCs properties.
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http://dx.doi.org/10.1166/jnn.2016.11016DOI Listing
May 2016

MicroRNA-205-5p is upregulated in myelodysplastic syndromes and induces cell proliferation via PTEN suppression.

Leuk Res 2016 08 16;47:172-7. Epub 2016 Jun 16.

Department of Laboratory Medicine, Chosun University College of Medicine, Gwangju, Republic of Korea. Electronic address:

Micro (mi)RNA dysregulation is implicated in the development of myelodysplastic syndrome (MDS). Chromosomal abnormalities on 1q are frequently detected in Korean patients with MDS; however, how these are related to disease development is unknown. The present study compared the expression profiles of miRNAs encoded by chromosome 1q between 65 MDS patients and 11 controls. We found that miR-205-5p levels were 12.5 fold higher in the former (P=0.001). miR-205-5p level was increased in 44.7% of patients when an arbitrary 2(-ΔCt) cut-off value of 1.25 was used. miR-205-5p expression data were used to generate a receiver operating characteristic (ROC) curve for miR-205-5p, for which the area under the curve (AUC) was 0.825 (95% confidence interval: 0.710-0.941; P=0.001). Moreover, transfection with a miR-205-5p mimic induced cell proliferation by inhibiting the expression of the tumor suppressor protein phosphatase and tensin homolog (PTEN). Our findings suggest that miR-205-5p upregulation contributes to MDS by suppressing PTEN and that miR-205-5p thus acts as an oncogene in hematopoietic cells.
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http://dx.doi.org/10.1016/j.leukres.2016.06.003DOI Listing
August 2016

Development and Evaluation of Species-Specific PCR for Detection of Nine Acinetobacter Species.

Ann Clin Lab Sci 2016 May;46(3):270-8

Department of Laboratory Medicine, Chosun University Medical School, Gwang-Ju, South Korea.

Molecular methods have the potential to improve the speed and accuracy of Acinetobacter species identification in clinical settings. The goal of this study is to develop species-specific PCR assays based on differences in the RNA polymerase beta-subunit gene (rpoB) to detect nine commonly isolated Acinetobacter species including Acinetobacter baumannii, Acinetobacter calcoaceticus, Acinetobacter pittii, Acinetobacter nosocomialis, Acinetobacter lwoffii, Acinetobacter ursingii, Acinetobacter bereziniae, Acinetobacter haemolyticus, and Acinetobacter schindleri. The sensitivity and specificity of these nine assays were measured using genomic DNA templates from 55 reference strains and from 474 Acinetobacter clinical isolates. The sensitivity of A. baumannii-specific PCR assay was 98.9%, and the sensitivity of species-specific PCR assays for all other species was 100%. The specificities of A. lwoffii- and A. schindleri-specific PCR were 97.8 and 98.9%, respectively. The specificity of species-specific PCR for all other tested Acinetobacter species was 100%. The lower limit of detection for the nine species-specific PCR assays developed in this study was 20 or 200 pg of genomic DNA from type strains of each species. The Acinetobacter species-specific PCR assay would be useful to determine the correct species among suggested candidate Acinetobacter species when conventional methods including MALDI-TOF MS identify Acinetobacter only to the genus level. The species-specific assay can be used to screen large numbers of clinical and environmental samples obtained for epidemiologic study of Acinetobacter for the presence of target species.
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May 2016

A nondestructive approach for discrimination of the origin of sesame seeds using ED-XRF and NIR spectrometry with chemometrics.

Food Sci Biotechnol 2016 30;25(2):433-438. Epub 2016 Apr 30.

1School of Food Science and Biotechnology, Kyungpook National University, Daegu, 41566 Korea.

An energy dispersive X-ray fluorescence (ED-XRF) spectrometer and a near infrared (NIR) spectrometer combined with chemometrics were applied for origin discrimination of 48 Korean, 44 Chinese, and 21 Indian sesame seed samples used for development of a discriminant calibration model. Multi-elemental ED-XRF analysis based on Mg, Al, Si, P, S, Cl, K, Ca, Mn, Fe, and Cu was used for comparisons among origins. All elements, except for Fe, showed differences and 96.5% of seed samples were assigned to the correct origin using discriminant analysis based on chemical analytical results. NIR measurements were performed for spectral scanning. Classification of seeds using NIR discriminant analysis achieved 89.4% of seed samples assigned to the correct origin. Both ED-XRF and NIR are useful as nondestructive tools for discrimination of sesame seed origins.
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http://dx.doi.org/10.1007/s10068-016-0059-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6049197PMC
April 2016

Necrosis-inducing peptide has the beneficial effect on killing tumor cells through neuropilin (NRP-1) targeting.

Oncotarget 2016 May;7(22):32449-61

Department of Biochemistry, Chosun University School of Medicine, Dong-Gu, Gwang-Ju, Korea.

The therapeutic efficacy of most anti-cancer drugs depends on their apoptosis-inducing abilities. Previously, we showed that a peptide containing the mitochondrial targeting domain (MTD) found in Noxa, a BH-3 only protein of Bcl-2 family, induces necrosis. Here, a fusion peptide of neuropilin-1 (NRP-1) targeting peptide and MTD peptide, designated tumor homing motif 17:MTD (TU17:MTD), was found to induce necrosis in cancer cells in vitro and to cause the regression of tumors when intravenously injected into mice bearing subcutaneous CT26 colorectal carcinoma tumors. The necrosis within tumor tissues was evident upon administering TU17:MTD. TU17:MTD penetrated into tumor cells by targeting to Neuropilin-1, which could be blocked by anti-NRP-1 antibody. The efficacy of TU17:MTD on tumor regression was higher than that of TU17:D(KLAKLAK)2, a fusion peptide of NRP-1 targeting peptide and a pro-apoptotic peptide. The necrotic cell death within tumor tissues was evident at day 1 after administering TU17:MTD systemically. Transplanted subcutaneous substantially reduced in size within two weeks and 5 days, respectively, with no apparent side effects. Together, these results propose that the pro-necrotic peptide MTD may present an alternative approach for development of targeted anti-cancer agents.
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http://dx.doi.org/10.18632/oncotarget.8719DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5078025PMC
May 2016

The Mechanism of Allelic Competition in the ABO 547G>A Mutant is Associated with Decreased Activity of Glycosyltransferase B.

Ann Clin Lab Sci 2016 ;46(1):106-9

Department of Laboratory Medicine, Chonbuk National University Medical School, Jeonju, Korea Research Institute of Clinical Medicine of Chonbuk National University-Biomedical Research Institute of Chonbuk National University Hospital, Korea

The 547G>A polymorphism demonstrates significant allelic competition in people who harbor the B306 allele. We have performed the full sequencing of ABO gene in family members and measured their serum glycosyltransferase activity for demonstrating the cause of allelic competition. Genetic study including two regulatory regions and exon 1, and exons 2-7 of ABO gene demonstrated c.547G>A in exon 7 of the proband and her second son. The ABO genotype of the proband, husband, first son, and other son was ABO*A102/ABO*B306, ABO*A105/ABO*O02, ABO*A102/ABO*O02, and ABO*B306/ABO*O02 respectively. Serum glycosyltransferse B activity in the proband and her second son was lower than in normal B controls. We infer that allelic competition in the the 547G>A carrying individuals is associated with reduced activity of glycosyltransferase B.
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December 2016

In Vitro Interactions of Antibiotic Combinations of Colistin, Tigecycline, and Doripenem Against Extensively Drug-Resistant and Multidrug-Resistant Acinetobacter baumannii.

Ann Lab Med 2016 Mar;36(2):124-30

Department of Laboratory Medicine, College of Medicine, Chosun University, Gwangju, Korea.

Background: Acinetobacter baumannii infections are difficult to treat owing to the emergence of various antibiotic resistant isolates. Because treatment options are limited for multidrug-resistant (MDR) A. baumannii infection, the discovery of new therapies, including combination therapy, is required. We evaluated the synergistic activity of colistin, doripenem, and tigecycline combinations against extensively drug-resistant (XDR) A. baumannii and MDR A. baumannii.

Methods: Time-kill assays were performed for 41 XDR and 28 MDR clinical isolates of A. baumannii by using colistin, doripenem, and tigecycline combinations. Concentrations representative of clinically achievable levels (colistin 2 μg/mL, doripenem 8 μg/mL) and achievable tissue levels (tigecycline 2 μg/mL) for each antibiotic were used in this study.

Results: The colistin-doripenem combination displayed the highest rate of synergy (53.6%) and bactericidal activity (75.4%) in 69 clinical isolates of A. baumannii. Among them, the-doripenem-tigecycline combination showed the lowest rate of synergy (14.5%) and bactericidal activity (24.6%). The doripenem-tigecycline combination showed a higher antagonistic interaction (5.8%) compared with the colistin-tigecycline (1.4%) combination. No antagonism was observed for the colistin-doripenem combination.

Conclusions: The colistin-doripenem combination is supported in vitro by the high rate of synergy and bactericidal activity and lack of antagonistic reaction in XDR and MDR A. baumannii. It seems to be necessary to perform synergy tests to determine the appropriate combination therapy considering the antagonistic reaction found in several isolates against the doripenem-tigecycline and colistin-tigecycline combinations. These findings should be further examined in clinical studies.
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http://dx.doi.org/10.3343/alm.2016.36.2.124DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4713845PMC
March 2016

Primary mucinous cystadenocarcinoma of the renal pelvis misdiagnosed as ureteropelvic junction stenosis with renal pelvis stone: a case report and literature review.

World J Surg Oncol 2015 Nov 26;13:324. Epub 2015 Nov 26.

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

Background: Primary mucinous adenocarcinoma of the renal pelvis is extremely rare, with only ~100 cases reported till now. Its presumed pathogenesis includes glandular metaplasia of the urothelium of the calyces and the pelvis and malignant transformation of the metaplasia. Unfortunately, it has no characteristic symptoms or radiological features. We report a case of primary mucinous adenocarcinoma of the renal pelvis misdiagnosed as ureteropelvic junction stenosis with a renal pelvis stone.

Case Presentation: A 50-year-old man presented with discomfort in his right flank after a fall. A physical examination was normal except mild costovertebral angle tenderness on the right side. The results of most laboratory tests were within normal limits. Plain radiography of the kidneys, ureter, and urinary bladder showed a large radio-opaque mass in the right kidney. Abdominal computed tomography showed a hyperdense mass with 2.62 × 5.70 cm size in the right renal pelvis and severe hydronephrosis and cortical thinning. Diuretic-enhanced 99mTc DTPA renal scanning showed that the relative function of the right versus the left kidney was 20 versus 80 %. On the basis of the imaging findings, kidney dysfunction due to ureteropelvic junction stenosis with a large stone was initially diagnosed. However, the drained urine volume was almost zero, and gelatinous material was aspirated when percutaneous nephrostomy was performed for decompression of hydronephrosis. Although the cytopathology of gelatinous material was negative for malignancy, we could not rule out other disease, such as hidden malignancies of the kidney. We therefore performed radical nephrectomy, and pathological examination of the kidney uncovered a mucinous cystadenocarcinoma in the renal pelvis. A bone scan and positron emission tomography showed no evidence of other malignancies, metastasis, or remnant cancer. The patient has been well, without evidence of tumour recurrence or metastasis, for 20 months after surgery.

Conclusions: Primary mucinous adenocarcinomas of the renal pelvis are extremely rare, and most are diagnosed via post-operative analysis of resected specimens. Although preoperative diagnosis is difficult, urologists should consider the possibility of primary mucinous adenocarcinoma in patients with severe hydronephrosis accompanied by renal stones and chronic inflammation.
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http://dx.doi.org/10.1186/s12957-015-0739-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4662030PMC
November 2015
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