1
|
Chan K, Keane A, Pradhan S, King T, Moroco A, Goyal N, Choi KY. Postoperative Urinary Complications in Head and Neck Free Flap Reconstructive Surgery. Ann Otol Rhinol Laryngol 2024; 133:284-291. [PMID: 37902061 PMCID: PMC10865755 DOI: 10.1177/00034894231208256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2023]
Abstract
OBJECTIVE The purpose of this study is to evaluate the postoperative urinary complications and the optimal timing of foley catheter removal in patients who underwent free flap reconstructive surgery for head and neck pathology. METHODS A retrospective case-control study of head and neck patients who underwent free flap reconstructive surgery at a single institution between January 2009 and December 2021 was conducted. Patient risk factors for postoperative urinary retention (POUR) were analyzed. Fisher Exact and Wilcoxon Rank Sum tests were used to evaluate rates of foley replacement, straight catheterization, and catheter-associated urinary tract infection (CAUTI) and associated risk factors. RESULTS Two hundred and eleven patients were included in this study. Older age, lower BMI, lower intraoperative fluid volumes, and need for straight catheterization were statistically significant for POUR requiring foley replacement. Shorter total (P = .04) and postoperative (P = .01) foley duration showed statistical significance for POUR requiring straight catheterization. About 60% of patients who had straight catheterization required a foley replacement (P < .001). Only one patient (0.5%) developed a urinary tract infection (UTI). CONCLUSION Foley catheter duration impacts the risk of POUR requiring straight catheterization and subsequently, foley replacement. Optimal timing for foley catheter removal in the postoperative period remains to be elucidated. Removal of catheters between 21 and 48 hours after surgery may decrease the risk of POUR without increasing the rate of CAUTI in patients with head and neck pathology undergoing free flap reconstructive surgery.
Collapse
Affiliation(s)
- Kimberly Chan
- Department of Otolaryngology – Head and Neck Surgery, The Pennsylvania State University, College of Medicine, Hershey, PA, USA
| | - Allison Keane
- Department of Otolaryngology – Head and Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Sandeep Pradhan
- Department of Public Health Sciences, The Pennsylvania State University, College of Medicine, Hershey, PA, USA
| | - Tonya King
- Department of Public Health Sciences, The Pennsylvania State University, College of Medicine, Hershey, PA, USA
| | - Annie Moroco
- Department of Otolaryngology – Head and Neck Surgery, Thomas Jefferson University, Sidney Kimmel Medical College, Philadelphia, PA, USA
| | - Neerav Goyal
- Department of Otolaryngology – Head and Neck Surgery, The Pennsylvania State University, College of Medicine, Hershey, PA, USA
| | - Karen Y. Choi
- Department of Otolaryngology – Head and Neck Surgery, The Pennsylvania State University, College of Medicine, Hershey, PA, USA
| |
Collapse
|
2
|
Choi KY, Patel SD, Lane C, Tucker J, Chan K, Pradhan S, Mahase SS, Tam SH, King TS. Elucidating survival and functional outcomes in patients with primary head and neck malignancies treated in academic versus community settings. Head Neck 2024; 46:398-407. [PMID: 38087455 DOI: 10.1002/hed.27588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 10/19/2023] [Accepted: 11/19/2023] [Indexed: 01/13/2024] Open
Abstract
BACKGROUND Differences in treatment outcomes between community or academic centers are incompletely understood. METHODS Retrospective review of head and neck cancer patients between 2010 and 2020 in a rural health region. Kaplan-Meier curves and log-rank tests were used to evaluate survival outcomes, along with bivariate and multivariable Cox proportional hazards models. Linear regression was used for functional outcomes of tracheotomy and gastrostomy tube dependence. RESULTS Two hundred and forty-eight patients treated at an academic center were compared with 94 patients treated in community centers. In multivariable analysis, the risk of death (HR = 0.60, p = 0.019), and risk of recurrence were lower (HR = 0.29, p < 0.001) for patients treated in academic centers. Patients treated in community centers had longer gastrostomy tube dependence (p = 0.002). CONCLUSION Our findings suggest that treatment at an academic center was associated with a lower risk of recurrence and shorter gastrostomy tube dependence compared to treatment in the community.
Collapse
Affiliation(s)
- Karen Y Choi
- Department of Otolaryngology-Head and Neck Surgery, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
| | - Shivam D Patel
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Ciaran Lane
- Department of Otolaryngology, Max Rady College of Medicine, University of Manitoba, Winnipeg, Canada
| | - Jacqueline Tucker
- Department of Otolaryngology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Kimberly Chan
- Department of Otolaryngology-Head and Neck Surgery, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
| | - Sandeep Pradhan
- Department of Public Health Sciences, Division of Biostatistics and Bioinformatics, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
| | - Sean S Mahase
- Department of Radiation Oncology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
| | - Samantha H Tam
- Department of Otolaryngology-Head and Neck Surgery, Henry Ford Medical Center, Detroit, Michigan, USA
| | - Tonya S King
- Department of Public Health Sciences, Division of Biostatistics and Bioinformatics, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
| |
Collapse
|
3
|
Choi KY, Hao Q, Carlisle K, Hollenbeak CS, Lai SY. Cost-Effectiveness of [ 99mTc]Tilmanocept Relative to [ 99mTc]Sulfur Colloid for Sentinel Lymph Node Biopsy in Early Stage Oral Cavity Cancer. Ann Surg Oncol 2023; 30:7689-7698. [PMID: 37556007 PMCID: PMC10562505 DOI: 10.1245/s10434-023-13937-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 06/29/2023] [Indexed: 08/10/2023]
Abstract
BACKGROUND Several studies have demonstrated varying rates of efficacy, reliability, and sensitivity of sentinel lymph node biopsy (SLNB) in identifying occult nodal disease for early stage oral cavity squamous cell carcinoma (OCSCC) depending on the radionuclide agent utilized. No head-to-head comparison of cost or clinical outcomes of SLNB when utilizing [99mTc]tilmanocept versus [99mTc]sulfur colloid has been performed. The goal of this study was to develop a decision model to compare the cost-effectiveness of [99mTc]tilmanocept versus [99mTc]sulfur colloid in early stage OCSCC. PATIENTS AND METHODS A decision model of disease and treatment as a function of SLNB was created. Patients with a negative SLNB entered a Markov model of the natural history of OCSCC parameterized with published data to simulate five states of health and iterated over a 30-year time horizon. Treatment costs and quality-adjusted life-years (QALYs) for each health state were included. The incremental cost-effectiveness ratio (ICER) was then estimated using $100,000 per additional QALY as the threshold for determining cost-effectiveness. RESULTS The base case cost-effectiveness analysis suggested [99mTc]tilmanocept was more effective than [99mTc]sulfur colloid by 0.12 QALYs (7.06 versus 6.94 QALYs). [99mTc]Tilmanocept was more costly, with a lifetime cost of $84,961 in comparison with $84,264 for sulfur colloid, however, the overall base case ICER was $5859 per additional QALY, well under the threshold for cost-effectiveness. Multiple one-way sensitivity analyses were performed, and demonstrated the model was robust to alternative parameter values. CONCLUSION Our analysis showed that while [99mTc]tilmanocept is more costly upfront, these costs are worth the additional QALYs gained by the use of [99mTc]tilmanocept.
Collapse
Affiliation(s)
- Karen Y Choi
- Penn State College of Medicine, Hershey Medical Center, Hershey, PA, USA.
- Department of Otolaryngology Head and Neck Surgery, Penn State Hershey Medical Center, Hershey, PA, USA.
| | - Qiang Hao
- Department of Health Policy and Administration, Penn State University, University Park, PA, USA
| | - Kathryn Carlisle
- Penn State College of Medicine, Hershey Medical Center, Hershey, PA, USA
| | | | - Stephen Y Lai
- Department of Head and Neck Surgery, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Department of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| |
Collapse
|
4
|
Choi KY, Hao Q, Carlisle K, Hollenbeak CS, Lai SY. ASO Visual Abstract: Cost-Effectiveness of [ 99mTc]Tilmanocept Relative to [ 99mTc]Sulfur Colloid for Sentinel Lymph Node Biopsy in Early Stage Oral Cavity Cancer. Ann Surg Oncol 2023; 30:7699. [PMID: 37592087 DOI: 10.1245/s10434-023-14110-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/19/2023]
Affiliation(s)
- Karen Y Choi
- Penn State College of Medicine, Hershey Medical Center, Hershey, PA, USA.
- Department of Otolaryngology Head and Neck Surgery, Penn State Hershey Medical Center, Hershey, PA, USA.
| | - Qiang Hao
- Department of Health Policy and Administration, Penn State University, University Park, PA, USA
| | - Kathryn Carlisle
- Penn State College of Medicine, Hershey Medical Center, Hershey, PA, USA
| | | | - Stephen Y Lai
- Department of Head and Neck Surgery, Department of Molecular and Cellular Oncology, Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| |
Collapse
|
5
|
Schmalbach CE, Ow TJ, Choi KY, O'Leary M, Lin A, Hughley BB, Emerick KS, Moore B, Lee NY, Zandberg DP, Wang SJ. American Head and Neck Society position statement on the use of PD-1 inhibitors for treatment of advanced cutaneous squamous cell carcinoma. Head Neck 2023; 45:32-41. [PMID: 36181317 DOI: 10.1002/hed.27202] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 09/12/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND A position statement put forth by the American Head and Neck Society (AHNS) was constructed to provide evidence-based treatment recommendations for PD-1 inhibitor use in advanced cutaneous squamous cell carcinoma (cSCC). Secondarily, we sought to identify knowledge gaps warranting further investigation. METHODS A literature search utilizing key terms: cutaneous squamous cell carcinoma, cutaneous cancer, checkpoint inhibitors, systemic therapy, Program Cell Death, PD-1 (PubMed, Cochrane, and Google Scholar) was carried out to generate evidence-based statements. The statements were distributed among the AHNS membership. Delphi methodology was applied to identify statements achieving 70% or greater consensus among the leadership team. RESULTS Twenty-six position statements achieved consensus. Knowledge gaps for future research included: impact of immunosuppression on cSCC staging and associated treatment; role of PD-1 inhibitors in immunosuppressed patients. CONCLUSION This comprehensive position statement put forth by the AHNS represents majority consensus by practicing head and neck surgeons throughout the country.
Collapse
Affiliation(s)
- Cecelia E Schmalbach
- Department of Otolaryngology - Head and Neck Surgery, Temple University, Philadelphia, Pennsylvania, USA
| | - Thomas J Ow
- Department of Otorhinolaryngology - Head and Neck Surgery, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Karen Y Choi
- Department of Otolaryngology - Head and Neck Surgery, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Miriam O'Leary
- Department of Otolaryngology - Head and Neck Surgery, Tufts University, Boston, Massachusetts, USA
| | - Alice Lin
- Department of Otolaryngology - Head and Neck Surgery, Kaiser Permanente, Los Angeles, California, USA
| | | | - Kevin S Emerick
- Department of Otolaryngology - Head and Neck Surgery, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, USA
| | - Brian Moore
- Ochsner Medical Center, New Orleans, Louisiana, USA
| | - Nancy Y Lee
- Memorial Sloan Kettering Cancer Center, Head and Neck Radiation Oncology, New York City, New York, USA
| | - Dan P Zandberg
- Division of Hematology/Oncology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Steven J Wang
- Department of Otolaryngology - Head and Neck Surgery, University of Arizona, Tucson, Arizona, USA
| |
Collapse
|
6
|
Chan K, Keane A, Aynardi J, Choi KY. Phrenic nerve schwannoma presenting as an asymptomatic neck mass. Clin Case Rep 2022; 10:e6784. [PMID: 36590669 PMCID: PMC9794921 DOI: 10.1002/ccr3.6784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 11/11/2022] [Accepted: 12/05/2022] [Indexed: 12/29/2022] Open
Abstract
Phrenic nerve schwannomas of the head and neck are exceedingly rare pathologies that can present as an asymptomatic neck mass. Surgery is the definitive treatment, and a conservative surgical approach is preferred if a benign pathology is suspected.
Collapse
Affiliation(s)
- Kimberly Chan
- College of MedicineThe Pennsylvania State UniversityHersheyPennsylvaniaUSA
| | - Allison Keane
- Department of Otolaryngology – Head and Neck SurgeryCollege of Medicine, The Pennsylvania State UniversityHersheyPennsylvaniaUSA
| | - Jason Aynardi
- Department of Pathology and Laboratory MedicineCollege of Medicine, The Pennsylvania State UniversityHersheyPennsylvaniaUSA
| | - Karen Y. Choi
- Department of Otolaryngology – Head and Neck SurgeryCollege of Medicine, The Pennsylvania State UniversityHersheyPennsylvaniaUSA
| |
Collapse
|
7
|
Ruszkay N, Tucker J, Choi KY. Otolaryngology in the face of A pandemic. Oper Tech Otolayngol Head Neck Surg 2022; 33:74-83. [PMID: 35502270 PMCID: PMC9045873 DOI: 10.1016/j.otot.2022.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Although infrequent, pandemics are serious public health concerns with unpredictable courses. The COVID-19 pandemic began over 2 years ago and is far from over. This pandemic has spread rapidly throughout the world and led to several million deaths, making it commonly compared to the deadly Spanish influenza pandemic. Policy and safety measures are constantly being adapted to reduce transmission rates. The pandemic places stress on all healthcare workers, but especially otolaryngology providers due to their direct contact with airway connected cavities. This puts them at high risk for infection and has impacted inpatient and outpatient otolaryngology care, as well as education, research, and mental health.
Collapse
Affiliation(s)
- Nicole Ruszkay
- Department of Otolaryngology - Head and Neck Surgery, Penn State Hershey Medical Center, Hershey, Pennsylvania
| | - Jacqueline Tucker
- College of Medicine, Pennsylvania State University, Hershey, Pennsylvania
| | - Karen Y Choi
- Department of Otolaryngology - Head and Neck Surgery, Penn State Hershey Medical Center, Hershey, Pennsylvania
- College of Medicine, Pennsylvania State University, Hershey, Pennsylvania
| |
Collapse
|
8
|
Daher GS, Choi KY, Wells JW, Goyal N. A Systematic Review of Oral Nutritional Supplement and Wound Healing. Ann Otol Rhinol Laryngol 2022; 131:1358-1368. [PMID: 35043693 DOI: 10.1177/00034894211069437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE To explore the current literature for effects of oral nutritional supplement on wound healing rates in humans. METHODS A systematic review of the literature was performed using the Medline and PubMed database following PRISMA guidelines. The PubMed database was searched using terms relating to oral nutritional supplement and wound healing from 1837 to March 2020. Study inclusion criteria were: (i) design: randomized controlled trials, clinical studies, observational studies, clinical trials; (ii) population: adults; and (iii) intervention: oral nutritional supplement. RESULTS The search yielded 2433 studies, 313 of which were clinical trials or clinical studies. After abstract review, 28 studies qualified to be included in the review evaluating the following supplementation categories on wound healing: protein and amino acids (10), mineral, vitamin and antioxidants (9), probiotics (1), and mixed nutrients (8). Arginine and omega-3 supplement were shown to improve wound healing in head and neck cancer patients with surgical wounds by decreasing incidence of postoperative complications and reducing length of hospital stay. Mineral, vitamins, and antioxidants enriched supplements were more beneficial in increasing wound healing than non-enriched protein supplement for diabetic foot and pressure ulcers. CONCLUSIONS Supplementation of a variety of nutrients had variable effects on improving wound healing in different types of wounds. However, further research on the impact of nutritional supplements on surgical wound healing is necessary. The impact of multiple nutrient formulations may also need to be further evaluated for efficacy.
Collapse
Affiliation(s)
- Ghazal S Daher
- The Pennsylvania State University, College of Medicine, Hershey, PA, USA
| | - Karen Y Choi
- Department of Otolaryngology - Head and Neck Surgery, Milton S. Hershey Medical Center, Hershey, PA, USA
| | - Jeffery W Wells
- Department of Otolaryngology - Head and Neck Surgery, Milton S. Hershey Medical Center, Hershey, PA, USA
| | - Neerav Goyal
- Department of Otolaryngology - Head and Neck Surgery, Milton S. Hershey Medical Center, Hershey, PA, USA
| |
Collapse
|
9
|
Tucker J, Sarsfield E, Choi KY, Goyal N. Educating School Nurses about Human Papillomavirus (HPV) Associated Cancers and the Importance of HPV Vaccination. J Community Health Nurs 2021; 38:201-208. [PMID: 34787044 DOI: 10.1080/07370016.2021.1972244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE To assess and improve school nurse knowledge of HPV-associated cancers. DESIGN An experimental quality improvement study. METHODS At a continuing education regional conference, an interactive HPV education session was provided. Pre- and post-education surveys were completed by attendees. FINDINGS After the educational intervention, 89.9% of nurses indicated a change in knowledge and 83.2% indicated a planned change in practice. CONCLUSIONS An education intervention aimed at school nurses can be impactful in broadening the understanding of HPV oncogenesis. CLINICAL EVIDENCE Educational interventions can be a strategy to increase school nurse knowledge and subsequently patient knowledge about HPV associated cancers.
Collapse
Affiliation(s)
- Jacqueline Tucker
- College of Medicine, The Pennsylvania State University, Hershey, Pennsylvania, USA
| | - Erin Sarsfield
- Department of Otolaryngology, Head and Neck Surgery, College of Medicine, The Pennsylvania State University, Hershey, Pennsylvania, USA.,Penn State Health, Penn State Cancer Institute, Hershey, Pennsylvania, USA
| | - Karen Y Choi
- College of Medicine, The Pennsylvania State University, Hershey, Pennsylvania, USA.,Department of Otolaryngology, Head and Neck Surgery, College of Medicine, The Pennsylvania State University, Hershey, Pennsylvania, USA.,Penn State Health, Penn State Cancer Institute, Hershey, Pennsylvania, USA
| | - Neerav Goyal
- College of Medicine, The Pennsylvania State University, Hershey, Pennsylvania, USA.,Department of Otolaryngology, Head and Neck Surgery, College of Medicine, The Pennsylvania State University, Hershey, Pennsylvania, USA.,Penn State Health, Penn State Cancer Institute, Hershey, Pennsylvania, USA
| |
Collapse
|
10
|
Benyo S, Keane A, Warrick J, Choi KY. HPV-positive oral papillomas in an adolescent-A diagnostic dilemma. Clin Case Rep 2021; 9:e04546. [PMID: 34401152 PMCID: PMC8347631 DOI: 10.1002/ccr3.4546] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 06/09/2021] [Accepted: 06/16/2021] [Indexed: 12/31/2022] Open
Abstract
Human papillomavirus oral papilloma is often sexually transmitted, but non-sexual modes of transmission should be considered, including autoinoculation from skin lesions. A patient-centered multimodality approach should be utilized in the pediatric population.
Collapse
Affiliation(s)
- Sarah Benyo
- The Pennsylvania State UniversityCollege of MedicineHersheyPAUSA
| | - Allison Keane
- Department of Otolaryngology – Head and Neck SurgeryThe Pennsylvania State UniversityCollege of MedicineHersheyPAUSA
| | - Joshua Warrick
- Department of Pathology and Laboratory Medicine, The Pennsylvania State UniversityCollege of MedicineHersheyPAUSA
| | - Karen Y. Choi
- Department of Otolaryngology – Head and Neck SurgeryThe Pennsylvania State UniversityCollege of MedicineHersheyPAUSA
| |
Collapse
|
11
|
Leng Y, Chow DLY, Chui SK, Ip NSK, Chan SWC, Choi KY, Li AOC. Distribution of Urate Crystal Deposition in the Hands and Wrists of Patients with Chronic Gout. Hong Kong Journal of Radiology 2021. [DOI: 10.12809/hkjr2117173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Y Leng
- Department of Radiology, Tuen Mun Hospital, Hong Kong
| | - DLY Chow
- Department of Radiology, Tuen Mun Hospital, Hong Kong
| | - SK Chui
- Department of Radiology, Tuen Mun Hospital, Hong Kong
| | - NSK Ip
- Department of Radiology, Tuen Mun Hospital, Hong Kong
| | - SWC Chan
- Department of Radiology, Tuen Mun Hospital, Hong Kong
| | - KY Choi
- Department of Orthopaedics and Traumatology, Tuen Mun Hospital, Hong Kong
| | - AOC Li
- Department of Radiology, Tuen Mun Hospital, Hong Kong
| |
Collapse
|
12
|
Choi KY, Amit M, Tam S, Bell D, Phan J, Garden AS, Williams MD, Ferrarotto R, El-Naggar AK, Raza SM, DeMonte F, Kupferman ME, Hanna EY, Su SY. Clinical Implication of Diagnostic and Histopathologic Discrepancies in Sinonasal Malignancies. Laryngoscope 2020; 131:E1468-E1475. [PMID: 32946597 DOI: 10.1002/lary.29102] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 08/14/2020] [Accepted: 08/25/2020] [Indexed: 02/03/2023]
Abstract
OBJECTIVES To evaluate the incidence of histopathologic diagnostic discrepancy for patients referred to our institution, identify pathologies susceptible to diagnostic error, and assess the impact on survival of histopathologic diagnostic discrepancies. METHODS Three hundred ninety-seven patients with sinonasal cancers were identified, and discordance between the outside pathologic report and MD Anderson Cancer Center pathologic report was assessed. Overall survival and disease-specific survival were analyzed using Kaplan-Meier and log rank methods. RESULTS Discordance of major histopathologic diagnoses was present in 24% (97 of 397) of reports, with sinonasal undifferentiated carcinoma, sarcoma, neuroendocrine carcinoma, and poorly differentiated carcinoma pathologies having the highest change in diagnosis (P < .01). A further 61% (244 of 397) had minor changes such as histologic grade, subtype, or stage, with sarcoma and neuroendocrine carcinoma pathologies being most susceptible to change (P < .02). Overall, the 5-year overall survival (OS) and disease-specific survival (DSS) was reduced in patients with a major change in histopathologic diagnosis (59.2% vs. 70.2% (P = .02) and 72.9% vs. 81.2% (P = .02), respectively). Furthermore, patients with a major change in diagnosis and prior treatment experienced a significant reduction in 5-year OS (61.9% vs. 70.4%, P = .03 < .01) and DSS (72.4% vs. 81.5%, P = .04). CONCLUSION Histopathological diagnosis of sinonasal tumors is complex and challenging given the rarity of the disease. Obtaining the correct diagnosis is important for treatment selection and survival. In histologies prone to misdiagnoses, obtaining a second opinion from experienced head and neck pathologists at a high-volume institution may potentially lead to a change in treatment recommendations that could result in improved survival in patients with sinonasal malignancies. LEVEL OF EVIDENCE 4 Laryngoscope, 131:E1468-E1475, 2021.
Collapse
Affiliation(s)
- Karen Y Choi
- Department of Otolaryngology Head and Neck Surgery, The Pennsylvania State University, College of Medicine, Hershey, Pennsylvania, U.S.A
| | - Moran Amit
- Department of Head and Neck Surgery, University of Texas MD Anderson Cancer Center, Houston, Texas, U.S.A
| | - Samantha Tam
- Department of Head and Neck Surgery, University of Texas MD Anderson Cancer Center, Houston, Texas, U.S.A
| | - Diana Bell
- Department of Head and Neck Surgery, University of Texas MD Anderson Cancer Center, Houston, Texas, U.S.A
| | - Jack Phan
- Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas, U.S.A
| | - Adam S Garden
- Department of Head and Neck Surgery, University of Texas MD Anderson Cancer Center, Houston, Texas, U.S.A
| | - Michelle D Williams
- Department of Pathology, University of Texas MD Anderson Cancer Center, Houston, Texas, U.S.A
| | - Renata Ferrarotto
- Department of Thoracic, Head and Neck Medical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas, U.S.A
| | - Adel K El-Naggar
- Department of Pathology, University of Texas MD Anderson Cancer Center, Houston, Texas, U.S.A
| | - Shaan M Raza
- Department of Head and Neck Surgery, University of Texas MD Anderson Cancer Center, Houston, Texas, U.S.A
| | - Franco DeMonte
- Department of Neurosurgery, University of Texas MD Anderson Cancer Center, Houston, Texas, U.S.A
| | - Michael E Kupferman
- Department of Head and Neck Surgery, University of Texas MD Anderson Cancer Center, Houston, Texas, U.S.A
| | - Ehab Y Hanna
- Department of Head and Neck Surgery, University of Texas MD Anderson Cancer Center, Houston, Texas, U.S.A
| | - Shirley Y Su
- Department of Head and Neck Surgery, University of Texas MD Anderson Cancer Center, Houston, Texas, U.S.A
| |
Collapse
|
13
|
Hennessy M, Bann DV, Patel VA, Saadi R, Krempl GA, Deschler DG, Goyal N, Choi KY. Commentary on the management of total laryngectomy patients during the COVID-19 pandemic. Head Neck 2020; 42:1137-1143. [PMID: 32298016 PMCID: PMC7262329 DOI: 10.1002/hed.26183] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 04/04/2020] [Indexed: 01/19/2023] Open
Abstract
The coronavirus disease‐2019 (COVID‐19) pandemic has rapidly spread across the world, placing unprecedented strain on the health care system. Health care resources including hospital beds, ICUs, as well as personal protective equipment are becoming increasingly rationed and scare commodities. In this environment, the laryngectomee (patient having previously undergone a total laryngectomy) continues to represent a unique patient with unique needs. Given their surgically altered airway, they pose a challenge to manage for the otolaryngologist within the current COVID‐19 pandemic. In this brief report, we present special considerations and best practice recommendations in the management of total laryngectomy patients. We also discuss recommendations for laryngectomy patients and minimizing community exposures.
Collapse
Affiliation(s)
- Max Hennessy
- Department of Otolaryngology-Head and Neck Surgery, The Pennsylvania State University, College of Medicine, Hershey, Pennsylvania, USA
| | - Darrin V Bann
- Department of Otolaryngology-Head and Neck Surgery, The Pennsylvania State University, College of Medicine, Hershey, Pennsylvania, USA
| | - Vijay A Patel
- Department of Otolaryngology-Head and Neck Surgery, The Pennsylvania State University, College of Medicine, Hershey, Pennsylvania, USA
| | - Robert Saadi
- Department of Otolaryngology-Head and Neck Surgery, The Pennsylvania State University, College of Medicine, Hershey, Pennsylvania, USA
| | - Greg A Krempl
- Department of Otolaryngology-Head and Neck Surgery, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Daniel G Deschler
- Department of Otolaryngology-Head and Neck Surgery, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, USA
| | - Neerav Goyal
- Department of Otolaryngology-Head and Neck Surgery, The Pennsylvania State University, College of Medicine, Hershey, Pennsylvania, USA
| | - Karen Y Choi
- Department of Otolaryngology-Head and Neck Surgery, The Pennsylvania State University, College of Medicine, Hershey, Pennsylvania, USA
| |
Collapse
|
14
|
Tsay AJ, Paine AR, Lighthall JG, Choi KY, Hebel J, Flamm A. A possible pitfall of Mohs surgery in collision tumor diagnosis: A case of a squamous cell carcinoma of the scalp overlying a metastatic breast lesion of the skull. JAAD Case Rep 2020; 6:119-121. [PMID: 32016155 PMCID: PMC6992889 DOI: 10.1016/j.jdcr.2019.12.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Affiliation(s)
- Annie J Tsay
- Penn State College of Medicine, Hershey, Pennsylvania
| | - Allison R Paine
- Department of Dermatology, Penn State Milton S. Hershey Medical Center, Hershey, Pennsylvania
| | - Jessyka G Lighthall
- Section of Facial Plastic and Reconstructive Surgery, Penn State Milton S. Hershey Medical Center, Hershey, Pennsylvania
| | - Karen Y Choi
- Division of Otolaryngology-Head and Neck Surgery, Penn State Milton S. Hershey Medical Center, Hershey, Pennsylvania
| | - Jeanette Hebel
- Dermatology Associates of Lancaster, Lancaster, Pennsylvania
| | - Alexandra Flamm
- Department of Dermatology, Penn State Milton S. Hershey Medical Center, Hershey, Pennsylvania
| |
Collapse
|
15
|
Choi KY. Book Review: Neck Dissection. Ann Otol Rhinol Laryngol 2019. [DOI: 10.1177/0003489419842086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
16
|
Shin HR, Bae HS, Kim BS, Yoon HI, Cho YD, Kim WJ, Choi KY, Lee YS, Woo KM, Baek JH, Ryoo HM. PIN1 is a new therapeutic target of craniosynostosis. Hum Mol Genet 2019; 27:3827-3839. [PMID: 30007339 PMCID: PMC6216213 DOI: 10.1093/hmg/ddy252] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 07/05/2018] [Indexed: 01/14/2023] Open
Abstract
Gain-of-function mutations in fibroblast growth factor receptors (FGFRs) cause congenital skeletal anomalies, including craniosynostosis (CS), which is characterized by the premature closure of craniofacial sutures. Apert syndrome (AS) is one of the severest forms of CS, and the only treatment is surgical expansion of prematurely fused sutures in infants. Previously, we demonstrated that the prolyl isomerase peptidyl-prolyl cis-trans isomerase interacting 1 (PIN1) plays a critical role in mediating FGFR signaling and that Pin1+/- mice exhibit delayed closure of cranial sutures. In this study, using both genetic and pharmacological approaches, we tested whether PIN1 modulation could be used as a therapeutic regimen against AS. In the genetic approach, we crossbred Fgfr2S252W/+, a mouse model of AS, and Pin1+/- mice. Downregulation of Pin1 gene dosage attenuated premature cranial suture closure and other phenotypes of AS in Fgfr2S252W/+ mutant mice. In the pharmacological approach, we intraperitoneally administered juglone, a PIN1 enzyme inhibitor, to pregnant Fgfr2S252W/+ mutant mice and found that this treatment successfully interrupted fetal development of AS phenotypes. Primary cultured osteoblasts from Fgfr2S252W/+ mutant mice expressed high levels of FGFR2 downstream target genes, but this phenotype was attenuated by PIN1 inhibition. Post-translational stabilization and activation of Runt-related transcription factor 2 (RUNX2) in Fgfr2S252W/+ osteoblasts were also attenuated by PIN1 inhibition. Based on these observations, we conclude that PIN1 enzyme activity is important for FGFR2-induced RUNX2 activation and craniofacial suture morphogenesis. Moreover, these findings highlight that juglone or other PIN1 inhibitors represent viable alternatives to surgical intervention for treatment of CS and other hyperostotic diseases.
Collapse
Affiliation(s)
- H R Shin
- BK21 Program, Department of Molecular Genetics and Dental Pharmacology and Therapeutics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - H S Bae
- BK21 Program, Department of Molecular Genetics and Dental Pharmacology and Therapeutics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - B S Kim
- BK21 Program, Department of Molecular Genetics and Dental Pharmacology and Therapeutics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - H I Yoon
- BK21 Program, Department of Molecular Genetics and Dental Pharmacology and Therapeutics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Y D Cho
- BK21 Program, Department of Molecular Genetics and Dental Pharmacology and Therapeutics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea.,Department of Periodontology, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - W J Kim
- BK21 Program, Department of Molecular Genetics and Dental Pharmacology and Therapeutics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - K Y Choi
- Department of Plastic and Reconstructive Surgery, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Y S Lee
- BK21 Program, Department of Molecular Genetics and Dental Pharmacology and Therapeutics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - K M Woo
- BK21 Program, Department of Molecular Genetics and Dental Pharmacology and Therapeutics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - J H Baek
- BK21 Program, Department of Molecular Genetics and Dental Pharmacology and Therapeutics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - H M Ryoo
- BK21 Program, Department of Molecular Genetics and Dental Pharmacology and Therapeutics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| |
Collapse
|
17
|
Amit M, Tam S, Takahashi H, Choi KY, Zafereo M, Bell D, Weber RS. Prognostic performance of the American Joint Committee on Cancer 8th edition of the TNM staging system in patients with early oral tongue cancer. Head Neck 2018; 41:1270-1276. [PMID: 30537405 DOI: 10.1002/hed.25553] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 09/13/2018] [Accepted: 10/31/2018] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The 8th edition of the American Joint Committee on Cancer's (AJCC) staging system for oral cavity cancer incorporates pathological features. We aimed to assess whether these changes results in better risk stratification of patients with early oral tongue squamous cell carcinoma (OTSCC). METHODS Overall survival (OS) and disease-specific survival (DSS) of 244 patients were calculated using the Kaplan-Meier method. Multivariate analysis with stepwise selection was performed using Cox proportional hazards regression. RESULTS Sixty-two patients (25%) were upstaged using the 8th edition. Multivariate analysis revealed that overall stage using the 8th edition of the AJCC staging system but not using the 7th edition was a significant predictor for both OS and DSS. The 8th edition had lower Akaike information criterion and improved concordance index values compared with the 7th edition. CONCLUSION The 8th edition of AJCC allows better risk stratification and more precise counseling of patients with OTSCC who were previously considered at low risk.
Collapse
Affiliation(s)
- Moran Amit
- Departments of Head and Neck Surgery, The University of Texas M. D. Anderson Cancer Center, Houston, Texas.,Head and Neck Surgery and the Laboratory for Head and Neck Cancer Research, Houston Methodist research institute, Houston Methodist hospital, Houston, Texas
| | - Samantha Tam
- Departments of Head and Neck Surgery, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
| | - Hideaki Takahashi
- Departments of Head and Neck Surgery, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
| | - Karen Y Choi
- Departments of Head and Neck Surgery, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
| | - Mark Zafereo
- Departments of Head and Neck Surgery, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
| | - Diana Bell
- Departments of Pathology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
| | - Randal S Weber
- Departments of Head and Neck Surgery, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
| |
Collapse
|
18
|
Kim K, Choi KY, Kim JH, Park IS, Rho YS, Lee DJ. Base of tongue cancer-is it tongue cancer located at the base of the tongue, or is it a type of lingual tonsil cancer? The perspective from a genomic analysis. Int J Oral Maxillofac Surg 2018; 47:846-853. [PMID: 29452725 DOI: 10.1016/j.ijom.2018.01.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 12/05/2017] [Accepted: 01/26/2018] [Indexed: 11/26/2022]
Abstract
The aim of this study was to determine whether base of tongue (BOT) cancer is tongue cancer located at the base of the tongue or lingual tonsil cancer originating from tonsil tissue. This was a retrospective study using data from The Cancer Genome Atlas (TCGA). The genomic patterns of three primary cancers (BOT, oral tongue, and tonsil) were compared to determine their similarities and differences. Gene expression data (n=193; 26 BOT, 125 oral tongue, and 42 tonsil cases), copy number alteration data (n=142; 19 BOT, 96 oral tongue, and 27 tonsil cases), and somatic mutation data (n=187; 25 BOT, 122 oral tongue, and 40 tonsil cases) were analyzed using the t-test, heatmap analysis, and OncoPrint, respectively. Clinical information for the three tumour groups was included in the analyses. When using multiplatform analysis, BOT cancer showed nearly the same genomic pattern as tonsil cancer, but not oral tongue cancer. The χ2 test and survival analysis revealed that BOT cancer had the same clinical and survival patterns as tonsil cancer. In conclusion, BOT cancer showed a genomic pattern similar to that of tonsil cancer, but different to that of oral tongue cancer. Further prospective studies are warranted before the results of this study can be applied in a clinical setting.
Collapse
Affiliation(s)
- K Kim
- Department of Otolaryngology-Head and Neck Surgery, Hallym University Medical Centre, Seoul, Republic of Korea
| | - K Y Choi
- Department of Otolaryngology-Head and Neck Surgery, Hallym University Medical Centre, Seoul, Republic of Korea
| | - J H Kim
- Department of Otolaryngology-Head and Neck Surgery, Hallym University Medical Centre, Seoul, Republic of Korea
| | - I S Park
- Department of Otolaryngology-Head and Neck Surgery, Hallym University Medical Centre, Seoul, Republic of Korea
| | - Y S Rho
- Department of Otolaryngology-Head and Neck Surgery, Hallym University Medical Centre, Seoul, Republic of Korea
| | - D J Lee
- Department of Otolaryngology-Head and Neck Surgery, Hallym University Medical Centre, Seoul, Republic of Korea.
| |
Collapse
|
19
|
Choi KY. Book Review: Differential Diagnosis in Neuroimaging: Head and Neck. Ann Otol Rhinol Laryngol 2017. [DOI: 10.1177/0003489417727523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
20
|
Spielman DB, Hsueh WD, Choi KY, Bent JP. From Morbidity and Mortality to Quality Improvement: Effects of a Structured and Interactive Otolaryngology Conference. OTO Open 2017; 1:2473974X17692775. [PMID: 30480176 PMCID: PMC6239051 DOI: 10.1177/2473974x17692775] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 12/22/2016] [Accepted: 01/18/2017] [Indexed: 11/16/2022] Open
Abstract
Objective Measure the effects of a structured morbidity and mortality conference format
on the attitudes of resident and faculty participants. Study Design Prospective cohort study. Setting Otorhinolaryngology–head and neck surgery residency training program. Subjects and Methods Two changes were implemented to the structure of our morbidity and mortality
conference: (1) we adopted a recently described presentation framework
called situation-background-assessment-recommendation and (2) appointed a
faculty moderator to lead the conference. Surveys were distributed to
residents and faculty before and after these modifications were implemented
to measure changes in attitude of conference attendees. Results After implementing the above changes to the morbidity and mortality
conference, participant engagement increased from “moderately engaged” to
“extremely engaged” (P < .01). Among both faculty and
residents, the perceived educational value of conference also improved from
“moderately educational” to “extremely educational” (P <
.01). Finally in the attending cohort, the impact on future patient care
increased from “no change” to “greatly enhanced” (P <
.01). Conclusion By implementing the situation-background-assessment-recommendation framework
and appointing a faculty moderator to morbidity and mortality conference,
participants reported significantly enhanced engagement during the
conference, increased educational value of the session, and a positive
impact on future patient care.
Collapse
Affiliation(s)
- Daniel B Spielman
- Otolaryngology-Head and Neck Surgery, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Wayne D Hsueh
- Otolaryngology-Head and Neck Surgery, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Karen Y Choi
- Otolaryngology-Head and Neck Surgery, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, USA
| | - John P Bent
- Otolaryngology-Head and Neck Surgery, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, USA
| |
Collapse
|
21
|
Choi KY. Book Review: Robotic Head and Neck Surgery: The Essential Guide. Ann Otol Rhinol Laryngol 2016. [DOI: 10.1177/0003489416654659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
22
|
Choi KY. Book Review: Vertigo: Clinical Practice and Examination. Ann Otol Rhinol Laryngol 2016. [DOI: 10.1177/0003489415604575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
23
|
Hong SM, Park CW, Kim SW, Nam YJ, Yu JH, Shin JH, Yun CH, Im SH, Kim KT, Sung YC, Choi KY. NAMPT suppresses glucose deprivation-induced oxidative stress by increasing NADPH levels in breast cancer. Oncogene 2015; 35:3544-54. [PMID: 26568303 DOI: 10.1038/onc.2015.415] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 09/03/2015] [Accepted: 09/04/2015] [Indexed: 12/21/2022]
Abstract
Nicotinamide phosphoribosyltransferase (NAMPT) is a rate-limiting enzyme involved in NAD+ biosynthesis. Although NAMPT has emerged as a critical regulator of metabolic stress, the underlying mechanisms by which it regulates metabolic stress in cancer cells have not been completely elucidated. In this study, we determined that breast cancer cells expressing a high level of NAMPT were resistant to cell death induced by glucose depletion. Furthermore, NAMPT inhibition suppressed tumor growth in vivo in a xenograft model. Under glucose deprivation conditions, NAMPT inhibition was found to increase the mitochondrial reactive oxygen species (ROS) level, leading to cell death. This cell death was rescued by treatment with antioxidants or NAD+. Finally, we showed that NAMPT increased the pool of NAD+ that could be converted to NADPH through the pentose phosphate pathway and inhibited the depletion of reduced glutathione under glucose deprivation. Collectively, our results suggest a novel mechanism by which tumor cells protect themselves against glucose deprivation-induced oxidative stress by utilizing NAMPT to maintain NADPH levels.
Collapse
Affiliation(s)
- S M Hong
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - C W Park
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), Pohang, Korea.,Biokogen Inc. POSTECH Biotech Center #226, Pohang, Korea
| | - S W Kim
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - Y J Nam
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - J H Yu
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - J H Shin
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - C H Yun
- Academy of Immunology and Microbiology (AIM), Institute for Basic Science (IBS), Pohang, Korea
| | - S-H Im
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), Pohang, Korea.,Academy of Immunology and Microbiology (AIM), Institute for Basic Science (IBS), Pohang, Korea
| | - K-T Kim
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - Y C Sung
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - K Y Choi
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| |
Collapse
|
24
|
Yau CH, Choi KY, Kwong NS, Lau PC, Yuen MK, Kwok NC, Chow YY, Siu SLY, Li KW, Lam DK. Frequency of developmental dysplasia of the hip in breech-presented Chinese neonates in Hong Kong. Hong Kong Med J 2012; 18:407-411. [PMID: 23018068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023] Open
Abstract
OBJECTIVES. To clarify the use of ultrasonography by determining the frequency of developmental dysplasia of the hip among breech-presented Chinese neonates in Hong Kong. DESIGN. Prospective case series. SETTING. Regional hospital, Hong Kong. PATIENTS. All breech-presented Chinese neonates born during January 2008 to June 2009 were included (except premature neonates). They were examined clinically from birth till the age of 1 year. Ultrasound of the hips was performed at the age of 2 weeks, and X-ray of the pelvis at the age of 1 year. RESULTS. A total of 209 breech-presented neonates were born during the study period; 110 neonates completed all necessary investigations and follow-up. Among the latter, there were three neonates with developmental dysplasia of the hip warranting treatment, which amounted to a frequency of 2.7%. CONCLUSION. Developmental dysplasia of the hip among breech-presented Chinese babies is only slightly less common than in corresponding populations in other regions in the world. Since early diagnosis is important, ultrasonography screening in high-risk cases such as those with breech presentation may be useful.
Collapse
Affiliation(s)
- C H Yau
- Department of Orthopaedics and Traumatology, Tuen Mun Hospital, Tuen Mun, Hong Kong
| | | | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Choi KY, Wang Z, Ozarowski A, van Tol J, Zhou HD, Wiebe CR, Skourski Y, Dalal NS. Spin dynamics of the S = 5/2 2D triangular antiferromagnet Ba3NbFe3Si2O14. J Phys Condens Matter 2012; 24:246001. [PMID: 22627202 DOI: 10.1088/0953-8984/24/24/246001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We report pulse-field magnetization, ac susceptibility, and 100 GHz electron spin resonance (ESR) measurements on the S = 5/2 two-dimensional triangular compound Ba3NbFe3Si2O14 with the Néel temperature T(N) = 26 K. The magnetization curve shows an almost linear increase up to 60 T with no indication of a one-third magnetization plateau. An unusually large frequency dependence of the ac susceptibility in the temperature range of T = 20-100 K reveals a spin-glass behavior or superparamagnetism, signaling the presence of frustration-related slow magnetic fluctuations. The temperature dependence of the ESR linewidth exhibits two distinct critical regimes; (i) ΔH(pp)(T) is proportional to (T-T(N))(-p) with the exponent p = 0.2(1)-0.2(3) for temperatures above 27 K, and (ii) ΔH(pp)(T) is proportional to (T-T*)(-p) with T* = 12 K and p = 0.8(1)-0.8(4) for temperatures between 12 and 27 K. This is interpreted as indicating a dimensional crossover of magnetic interactions and the persistence of short-range correlations with a helically ordered state.
Collapse
Affiliation(s)
- K Y Choi
- Department of Physics, Chung-Ang University, Seoul, Republic of Korea.
| | | | | | | | | | | | | | | |
Collapse
|
26
|
Cho YK, Choi MG, Oh SN, Baik CN, Park JM, Lee IS, Kim SW, Choi KY, Chung IS. Comparison of bolus transit patterns identified by esophageal impedance to barium esophagram in patients with dysphagia. Dis Esophagus 2012; 25:17-25. [PMID: 21668570 DOI: 10.1111/j.1442-2050.2011.01212.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Bolus transit through the esophagus has not been validated by videoesophagram in patients with dysphagia and changes in impedance with abnormal barium transit have not been described in those patients. The aim of this study was to compare esophageal impedance findings with barium esophagram measurements in patients with dysphagia. The consecutive patients with dysphagia underwent conventional multichannel esophageal impedance manometry, after which a barium videoesophagram was performed simultaneously with multichannel esophageal impedance manometry using a mean of three swallows of barium. Esophageal emptying patterns shown in the esophagogram were classified by the degree of intraesophageal stasis and presence of intraesophageal reflux. Bolus transit patterns in impedance were classified as complete and incomplete transit. Sixteen patients (M : F = 8 : 8, mean age, 47 years) were enrolled. Their manometric diagnosis were normal (n= 6), ineffective esophageal motility (n= 1), diffuse esophageal spasm (DES; n= 2), and achalasia (n= 7). Sixty-three swallows were analyzed. According to impedance analysis, 21/22 swallows with normal barium emptying showed complete transit (96%) and 31/32 swallows with severe stasis showed incomplete transit (97%). Nine swallows with mild stasis showed either complete or incomplete transit patterns in impedance. Swallows with mild barium stasis and complete transit in impedance were observed in patients who had received treatment (two patients with achalasia with history of esophageal balloonplasty and a patient with DES after nifedipine administration). Impedance reflected severe stasis with retrograde barium movement and described typical bolus transit patterns in patients with achalasia and DES. In conclusion, impedance-barium esophagram concordance is high for swallows with normal esophageal emptying and for severe barium stasis in patients with dysphagia.
Collapse
Affiliation(s)
- Y K Cho
- Division of Gastroenterology, Department of Internal Medicine, The Catholic University of Korea, Seoul, Korea
| | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Felea V, Lemmens P, Yasin S, Zherlitsyn S, Choi KY, Lin CT, Payen C. Magnetic phase diagram of multiferroic MnWO4 probed by ultrasound. J Phys Condens Matter 2011; 23:216001. [PMID: 21555835 DOI: 10.1088/0953-8984/23/21/216001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The magnetic phase diagram of multiferroic MnWO(4) is studied in magnetic fields up to 60 T using sound velocity and sound attenuation measurements. Anomalies are observed at temperatures T(N1) = 7.6 K, T(N2) = 12.6 K and T(N3) = 13.6 K that separate commensurate antiferromagnetic (AF1) to helical AF2 and commensurate AF3 to paramagnetic phases, respectively. The anomalies are significantly different and shed light on the spin-phonon coupling and evolution of the various order parameters in this multiferroic material. For temperatures below T(N2) pronounced field hysteresis effects are also observed in the sound velocity, indicating field-induced transformations. In the temperature dependence of the attenuation we observe anomalies distinctively different from the usual maxima related to relaxation effects. They are attributed to the combination of dispersion effects due to domain walls and the discontinuously changing sound velocity. In total, six different magnetic phases, at various temperatures and fields including a novel high-field phase, are revealed and analyzed.
Collapse
Affiliation(s)
- V Felea
- Institute for Condensed Matter Physics, TU Braunschweig, Braunschweig, Germany
| | | | | | | | | | | | | |
Collapse
|
28
|
Yeung YK, Ho ST, Yen CH, Ho PC, Tse WL, Lau YK, Choi KY, Choi ST, Lam MMY, Cheng SHS, Wong TC. Factors affecting mortality in Hong Kong patients with upper limb necrotising fasciitis. Hong Kong Med J 2011; 17:96-104. [PMID: 21471588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023] Open
Abstract
OBJECTIVE To identify predictive factors for mortality of patients with upper limb necrotising fasciitis. DESIGN Retrospective study. SETTING Six hospitals in Hong Kong. PATIENTS Clinical records of 29 patients treated in the hospitals were traced and analysed. MAIN OUTCOME MEASURES Possible predictive factors for mortality as evaluated by application of Fisher's test. RESULTS Overall mortality was 28%. Digital infections conferred a lower mortality, but progressive necrosis necessitated amputation. Vibrio vulnificus was the commonest organism identified in association with marine injury and in patients with cirrhosis. Prognostic indicators with decreasing significance include deranged renal and liver function, thrombocytopaenia, proximal involvement (elbow or above) initially, and presence of hypotension upon admission. CONCLUSION With a P value of less than 0.05, deranged renal and liver function, thrombocytopaenia, initial proximal involvement, and hypotension on admission were predictors of mortality in necrotising fasciitis affecting the upper limbs. The ALERTS (Abnormal Liver function, Extent of infection, Renal impairment, Thrombocytopenia, and Shock) score with a cutoff of 3 appeared to predict mortality.
Collapse
Affiliation(s)
- Y K Yeung
- Department of Orthopaedics, Caritas Medical Centre, Shamshuipo, Kowloon, Hong Kong.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
McGregor A, Choi KY, Schleiss MR. Guinea pig cytomegalovirus GP84 is a functional homolog of the human cytomegalovirus (HCMV) UL84 gene that can complement for the loss of UL84 in a chimeric HCMV. Virology 2010; 410:76-87. [PMID: 21094510 DOI: 10.1016/j.virol.2010.10.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 07/23/2010] [Accepted: 10/15/2010] [Indexed: 01/01/2023]
Abstract
The guinea pig cytomegalovirus (GPCMV) co-linear gene and potential functional homolog of HCMV UL84 (GP84) was investigated. The GP84 gene had delayed early transcription kinetics and transient expression studies of GP84 protein (pGP84) demonstrated that it targeted the nucleus and co-localized with the viral DNA polymerase accessory protein as described for HCMV pUL84. Additionally, pGP84 exhibited a transdominant inhibitory effect on viral growth as described for HCMV. The inhibitory domain could be localized to a minimal peptide sequence of 99 aa. Knockout of GP84 generated virus with greatly impaired growth kinetics. Lastly, the GP84 ORF was capable of complementing for the loss of the UL84 coding sequence in a chimeric HCMV. Based on this research and previous studies we conclude that GPCMV is similar to HCMV by encoding single copy co-linear functional homologs of HCMV UL82 (pp71), UL83 (pp65) and UL84 genes.
Collapse
Affiliation(s)
- A McGregor
- Center for Infectious Diseases and Microbiology, Translational Research and Division of Infectious Diseases, University of Minnesota Medical School, Department of Pediatrics, 2001 Sixth Street SE, Minneapolis, MN 55455, USA.
| | | | | |
Collapse
|
30
|
Kim TH, Lee JJ, Chung SH, Lee HH, Lee KH, Choi KY, Lee SH. Efficacy of assessment in fetal behaviour by four dimensional ultrasonography. J OBSTET GYNAECOL 2010; 30:439-43. [PMID: 20604642 DOI: 10.3109/01443615.2010.486084] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
This study was conducted to examine the behaviour and facial expressions of the fetus after birth by 4-dimensional (4-D) ultrasonography, and the association of the biophysical profile (BPP) with the Doppler scale. A total of 40 singleton pregnancies were included. All 4-D ultrasonographies were performed using the Accuvix XQ (Medison Co. Ltd, Seoul, Republic of Korea). The BPP and Doppler were performed on gravidas using 2-D ultrasonography. We recorded the newborn while awake no later than 48 h after delivery. The most frequent movement in fetuses and newborn was yawning and isolated arm movements, respectively. Sucking, swallowing (r = 0.78) and isolated limb movements (r = 0.72) in fetuses as observed by 4-D ultrasonography had a relationship with isolated limb movements in the newborn. Because of the limitation of ultrasonography, an overall comparison could not be made. There was a high correlation between sucking, swallowing, and isolated limb movements in fetuses and newborn.
Collapse
Affiliation(s)
- T-H Kim
- Department of Obstetrics and Gynecology, College of Medicine, Soonchunhyang University, Bucheon, Republic of Korea
| | | | | | | | | | | | | |
Collapse
|
31
|
Wang M, Holmes-Davis R, Rafinski Z, Jedrzejewska B, Choi KY, Zwick M, Bupp C, Izmailov A, Paczkowski J, Warner B, Koshinsky H. Accelerated photobleaching of a cyanine dye in the presence of a ternary target DNA, PNA probe, dye catalytic complex: a molecular diagnostic. Anal Chem 2010; 81:2043-52. [PMID: 19231844 DOI: 10.1021/ac702519k] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In many settings, molecular testing is needed but unavailable due to complexity and cost. Simple, rapid, and specific DNA detection technologies would provide important alternatives to existing detection methods. Here we report a novel, rapid nucleic acid detection method based on the accelerated photobleaching of the light-sensitive cyanine dye, 3,3'-diethylthiacarbocyanine iodide (DiSC(2)(3) I(-)), in the presence of a target genomic DNA and a complementary peptide nucleic acid (PNA) probe. On the basis of the UV-vis, circular dichroism, and fluorescence spectra of DiSC(2)(3) with PNA-DNA oligomer duplexes and on characterization of a product of photolysis of DiSC(2)(3) I(-), a possible reaction mechanism is proposed. We propose that (1) a novel complex forms between dye, PNA, and DNA, (2) this complex functions as a photosensitizer producing (1)O(2), and (3) the (1)O(2) produced promotes photobleaching of dye molecules in the mixture. Similar cyanine dyes (DiSC(3)(3), DiSC(4)(3), DiSC(5)(3), and DiSC(py)(3)) interact with preformed PNA-DNA oligomer duplexes but do not demonstrate an equivalent accelerated photobleaching effect in the presence of PNA and target genomic DNA. The feasibility of developing molecular diagnostic assays based on the accelerated photobleaching (the smartDNA assay) that results from the novel complex formed between DiSC(2)(3) and PNA-DNA is under way.
Collapse
Affiliation(s)
- M Wang
- Investigen Inc., Hercules, California, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Lumata LL, Choi KY, Brooks JS, Reyes AP, Kuhns PL, Wu G, Chen XH. 77Se and 63Cu NMR studies of the electronic correlations in CuxTiSe2 (x = 0.05, 0.07). J Phys Condens Matter 2010; 22:295601. [PMID: 21399313 DOI: 10.1088/0953-8984/22/29/295601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We report a (77)Se and (63)Cu nuclear magnetic resonance (NMR) investigation on the charge-density-wave (CDW) superconductor Cu(x)TiSe(2) (x = 0.05 and 0.07). At high magnetic fields where superconductivity is suppressed, the temperature dependence of (77)Se and (63)Cu spin-lattice relaxation rates 1/T(1) follow a linear relation. The slope of (77)Se 1/T(1) versus T increases with the Cu doping. This can be described by a modified Korringa relation which suggests the significance of electronic correlations and the Se 4p- and Ti 3d-band contribution to the density of states at the Fermi level in the studied compounds.
Collapse
Affiliation(s)
- L L Lumata
- Department of Physics, Florida State University, Tallahassee, FL 32310, USA.
| | | | | | | | | | | | | |
Collapse
|
33
|
Kim MY, Kaduwal S, Yang DH, Choi KY. Bone morphogenetic protein 4 stimulates attachment of neurospheres and astrogenesis of neural stem cells in neurospheres via phosphatidylinositol 3 kinase-mediated upregulation of N-cadherin. Neuroscience 2010; 170:8-15. [PMID: 20638445 DOI: 10.1016/j.neuroscience.2010.07.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Revised: 07/01/2010] [Accepted: 07/09/2010] [Indexed: 11/15/2022]
Abstract
The neurosphere culture system is useful for expanding neural stem cells (NSCs) without affecting self-renewal potential and multipotency. However, the extrinsic signals that affect the formation or dissociation of neurospheres are poorly understood. Here, we found that bone morphogenetic protein 4 (BMP4) induced the attachment of neurospheres, astrocytic differentiation, and migration of neurosphere NSCs. These outcomes were accompanied by Akt activation and upregulation of the adhesion molecule, N-cadherin. A phosphatidylinositol 3 kinase (PI3 kinase) inhibitor (LY294002) blocked attachment of neurosphere, astrocytic differentiation, migration, and N-cadherin upregulation of neurosphre NSCs. The PI3 kinase-Akt pathway appeared to selectively mediate the effects of BMP4, as neurosphere attachment was unaffected by MEK inhibitors (PD98059 and U0126). Importantly, a neutralizing N-cadherin antibody inhibited BMP4-induced neurosphere attachment, astrocytic differentiation, and migration of neurosphere NSCs. Together, these findings show that BMP4-induced attachment of neurospheres is related to the astrocytic differentiation of these cells and that these effects are attributable, at least in part, to PI3 kinase-Akt pathway-dependent induction of N-cadherin.
Collapse
Affiliation(s)
- M Y Kim
- Translational Research Center for Protein Function Control, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | | | | | | |
Collapse
|
34
|
Abstract
INTRODUCTION Because of the increasing use of magnetic resonance imaging (MRI), thoracic soft disc herniations are being easily detected in the early stages. To avoid a high morbidity rate and other complications that are associated with the conventional approach, the authors have applied a percutaneous endoscopic technique. METHODS From May 2001 to July 2007, fourteen patients with soft lateral or central thoracic disc herniation (TDH) underwent percutaneous endoscopic thoracic discectomy. Under local anesthesia with intravenous sedation, the authors removed the herniated disc through the thoracic intervertebral foramen after performing a foraminoplasty, which is the enlargement of the foramen by cutting the lateral and inferior part of the superior facet with a round cutter. The clinical outcome was evaluated using the visual analogue scale (VAS) and Oswestry disability index (ODI). RESULTS Six patients were male and eight were female, aged 21-75 years (mean: 48.1 years). Mean follow-up period was 60.2 months (15-89 months), mean operative time was 61 min. The mean VAS improved from 6.5 to 3.0 for back pain and 5.8 to 2.5 for leg pain at the final follow-up. The mean ODI scores also improved from 58.1 before surgery to 24.5 at the final follow-up. Conversion to an open procedure was not required for any of the patients. DISCUSSION As it has been proven to lessen the morbidity rate, this percutaneous endoscopic thoracic discectomy (PETD) technique for symptomatic soft TDH is a safe and effective method that provides a direct route to the lesion under local anesthesia.
Collapse
Affiliation(s)
- K Y Choi
- Department of Neurosurgery, Wooridul Spine Hospital, Seoul, Republic of Korea
| | | | | | | |
Collapse
|
35
|
Abstract
The relationship between the wax matrix in lipstick and sweating has been investigated by observing the change of size and shape of the wax matrix due to sweating by Scanning Electron Microscopy (SEM). For observation by SEM, a lipstick sample was frozen in liquid nitrogen. The oil in the lipstick was then extracted in cold isopropanol (-70 degrees C) for 1-3 days. After the isopropanol was evaporated, the sample was sputtered with gold and examined by SEM. The change of wax matrix underneath the surface from fine, uniform structure to coarse, nonuniform structure resulted from the caking of surrounding wax matrix. The oil underneath the surface migrated to the surface of lipstick with sweating; consequently the wax matrix in that region was rearranged into the coarse matrix. In case of flamed lipstick, sweating was delayed and the wax matrix was much coarser than that of the unflamed one. The larger wax matrix at the surface region was good for including oil. The effect of molding temperature on sweating was also studied. As the molding temperature rose, sweating was greatly reduced and the size of the wax matrix increased. It was found that sweating was influenced by the compatibility of wax and oil. A formula consisting of wax and oil that have good compatibility has a tendency to reduce sweating and increase the size of the wax matrix. When pigments were added to wax and oil, the size of the wax matrix was changed, but in all cases sweating was increased due to the weakening of the binding force between wax and oil. On observing the thick membrane of wax at the surface of lipstick a month after molding it was also found that sweating was influenced by ageing. In conclusion, the structure of the wax matrix at the surface region of lipstick was changed with the process of flaming, molding temperature, compatibility of wax and oil, addition of pigment, and ageing. In most cases, as the size of the wax matrix was increased, sweating was reduced and delayed.
Collapse
Affiliation(s)
- S Y Seo
- Household and Personal Care Products R&D Institute, LG Chemical Ltd. #84, Jang dong, Yusong gu, Taejon, 305-343, Korea
| | | | | | | | | | | |
Collapse
|
36
|
Pohl J, Blancas JM, Cave D, Choi KY, Delvaux M, Ell C, Gay G, Jacobs MAJM, Marcon N, Matsui T, May A, Mulder CJ, Pennazio M, Perez-Cuadrado E, Sugano K, Vilmann P, Yamamoto H, Yano T, Zhong JJ. Consensus report of the 2nd International Conference on double balloon endoscopy. Endoscopy 2008; 40:156-60. [PMID: 18253908 DOI: 10.1055/s-2007-966994] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- J Pohl
- Department of Internal Medicine II, Dr. Horst Schmidt Kliniken, Wiesbaden, Germany.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Abstract
We describe a case of esophageal perforation that resulted from a fishbone. A 71-year-old man had had a fishbone impacted in the lower esophagus for 2 days. At presentation, the bone was dislodged at endoscopy; one round opening in a deep ulceration was detected when the fishbone was removed. The perforation was closed by endoscopic hemoclipping, after the removal of the fishbone. A thoracic computed tomography revealed air around the esophagus, aorta and bronchus and the presence of a pleural effusion. These findings suggested mediastinal emphysema and mediastinitis due to the esophageal perforation after the removal of the fishbone. Esophagography revealed a focal esophageal defect and linear contrast leakage at the distal esophagus. The mediastinal emphysema and pleural effusion successfully resolved after the endoscopic hemoclip application and conservative management of the perforation.
Collapse
Affiliation(s)
- H Y Sung
- Division of Gastroenterology, Department of Internal Medicine, Catholic University of Korea, Seoul, Korea
| | | | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Chu W, Chan KH, Kwan CY, Choi KY. Degradation of atrazine by modified stepwise-Fenton's processes. Chemosphere 2007; 67:755-61. [PMID: 17140623 DOI: 10.1016/j.chemosphere.2006.10.039] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2006] [Revised: 10/09/2006] [Accepted: 10/11/2006] [Indexed: 05/12/2023]
Abstract
The removal of atrazine (ATZ) by stepwise Fenton's processes (stepwise-FP) was studied and the system models were developed through the examination of reaction kinetics. The study compared the performance of the removal of ATZ by conventional FP with stepwise-FP, where the total dose of H(2)O(2) was split and inputted into the system at different times and/or quantities. The performance of stepwise-FP was found to be better than that of conventional FP. This was probably due to the minimization of the peak concentration of H(2)O(2) in the solution, which reduced the probability that valuable H(2)O(2) and hydroxyl radicals would be consumed in forming weaker radicals. The reaction kinetics of the decay of ATZ in stepwise-FP was found to be a two-stage process; and in each stage, fast decay followed by stagnant decay was observed. Two characterized constants (the initial decay rate and the oxidative capacity) were introduced and were found to be useful in quantifying the stepwise-FP. The models for predicting stepwise-FP with respect to different dosing times and/or asymmetrical doses were developed, and were found to be very useful for evaluating the system performance and/or for process design.
Collapse
Affiliation(s)
- W Chu
- Department of Civil and Structural Engineering, Research Centre for Environmental Technology and Management, The Hong Kong Polytechnic University, Hunghom, Kowloon, Hong Kong.
| | | | | | | |
Collapse
|
39
|
Abstract
Polymorphisms in the promoter region of the serotonin reuptake transporter (SERT) gene may underlie the disturbance in gut function in patients with irritable bowel syndrome (IBS). Association studies of SERT polymorphisms and IBS have shown diverse results among different countries, which might be due to racial and subject composition differences. The aim of this study was to assess the potential association between SERT polymorphisms and IBS in Koreans. A total of 190 IBS patients, who met the Rome II criteria, and 437 healthy controls were subjected to genotyping. SERT polymorphisms differed in the IBS and control groups (P = 0.014). The SERT deletion/deletion genotype occurred with greater frequency in the diarrhoea-predominant IBS group than in the controls. A strong genotypic association was observed between the SERT deletion/deletion genotype and diarrhoea-predominant IBS (P = 0.012). None of the clinical symptoms analysed was significantly associated with the SERT genotypes. The frequency of the SERT insertion/insertion genotype was much lower than that of the other two genotypes. A significant association was observed between the SERT polymorphism and IBS, especially diarrhoea-predominant IBS, suggesting that the SERT gene is a potential candidate gene involved in IBS in Korea.
Collapse
Affiliation(s)
- J M Park
- Division of Gastroenterology, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Lemmens P, Choi KY, Gnezdilov V, Sherman EY, Chen DP, Lin CT, Chou FC, Keimer B. Anomalous electronic Raman scattering in NaxCoO2.yH2O. Phys Rev Lett 2006; 96:167204. [PMID: 16712268 DOI: 10.1103/physrevlett.96.167204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2005] [Indexed: 05/09/2023]
Abstract
Raman scattering experiments on NaxCoO2.yH2O single crystals show a broad electronic continuum with a pronounced peak around 100 cm(-1) and a cutoff at approximately 560 cm(-1) over a wide range of doping levels. The electronic Raman spectra in superconducting and nonsuperconducting samples are similar at room temperature, but evolve in markedly different ways with decreasing temperature. For superconducting samples, the low-energy spectral weight is depleted upon cooling below T* approximately 150 K, indicating the opening of a pseudogap that is not present in nonsuperconducting materials. Weak additional phonon modes observed below T* suggest that the pseudogap is associated with charge ordering.
Collapse
Affiliation(s)
- P Lemmens
- Max Planck Institute for Solid State Research, D-70569 Stuttgart, Germany and Institute for Condensed Matter Physics, TU Braunschweig, D-38106 Braunschweig, Germany
| | | | | | | | | | | | | | | |
Collapse
|
41
|
Kim YH, Lee JH, Yang SK, Kim TI, Kim JS, Kim HJ, Kim JI, Kim SW, Kim JO, Jung IK, Jung SA, Jung MK, Kim HS, Myung SJ, Kim WH, Rhee JC, Choi KY, Song IS, Hyun JH, Min YI. Primary colon lymphoma in Korea: a KASID (Korean Association for the Study of Intestinal Diseases) Study. Dig Dis Sci 2005; 50:2243-7. [PMID: 16416168 DOI: 10.1007/s10620-005-3041-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2005] [Accepted: 03/22/2005] [Indexed: 12/16/2022]
Abstract
Although almost all primary colorectal lymphomas are of B-cell lineage in Western countries, primary colorectal T-cell lymphomas are not uncommon in the East. The aim of this study was to review the clinical characteristics and treatment outcomes of primary colorectal lymphomas, with special emphasis on the differences between T-cell and B-cell lymphomas. Ninety-five cases of primary colorectal lymphomas that satisfied Dawson's criteria were identified from the clinical databases of 13 university hospitals in Korea. The mean age at the time of presentation was 51.1 years and the male:female ratio was 64:31. The clinical information, including endoscopic and histological characteristics, was retrospectively analyzed. Of the primary colorectal lymphomas, 78 cases (82.1%) were of B-lineage and 17 cases (17.9%) were of T-cell lineage. Patients with T-cell lymphomas presented at a younger age than patients with B-cell lymphomas (42.8 vs 52.9 years, respectively; P = 0.016). The most common presenting symptom was abdominal pain (87.1%) for B-cell lymphomas, whereas hematochezia or night fever was more common for T-cell lymphomas (52.9% and 35.3%, respectively). The most common endoscopic type was fungating mass (54.0%) for B-cell lymphomas and ulcerative/ulcero-infiltrative lesions (80.0%) for T-cell lymphomas. Intussusception was more common in B-cell lymphomas than in T-cell lymphomas (30.8% vs 5.9%, respectively; P = 0.035), but perforation was more common in T-cell lymphomas than in B-cell lymphomas (23.5% vs 3.8%, respectively; P = 0.005). The prognosis was significantly worse for T-cell lymphomas than for B-cell lymphomas (P = 0.002). Primary colorectal T-cell lymphomas are characterized by multifocal ulcerative lesions in relatively young patients, a high rate of hematochezia, fever, or perforation, and a poor prognosis even for cases of localized disease.
Collapse
Affiliation(s)
- Y-H Kim
- Sungkyunkwan University, Korea
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Kim JI, Kim SS, Park S, Han J, Kim JK, Han SW, Choi KY, Chung IS, Chung KW, Sun HS. Endoscopic hemoclipping using a transparent cap in technically difficult cases. Endoscopy 2003; 35:659-62. [PMID: 12929060 DOI: 10.1055/s-2003-41512] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND AND STUDY AIMS Technical difficulties have been experienced in endoscopic hemoclipping on the posterior wall of the body of the stomach because the angle of approach is tangential. It has been suggested that the use of a transparent cap on the tip of the endoscope could help to solve this problem. The purpose of this study was to examine the efficacy of endoscopic hemoclipping using a transparent cap over the tip of the endoscope. PATIENTS AND METHODS A total of 74 patients with a bleeding peptic ulcer or stigmata of recent hemorrhage underwent endoscopic hemoclipping. Technical difficulty in hemoclipping was experienced in 18 patients and the transparent cap was used in these cases. We therefore conducted a nonrandomized prospective study to compare bleeding control with the hemoclip with and without the aid of a transparent cap. RESULTS There were no statistically significant differences between the patients treated with the cap and those treated without the cap with regard to the initial hemostasis rate (94.4 % vs. 91.1 %), the rebleeding rate (11.7 % vs. 11.8 %), or the permanent hemostasis rate (94.4 % vs. 96.4 %). CONCLUSIONS Although there was no statistically significant difference between patients treated with or without a transparent cap, hemoclipping with the aid of the cap made it possible to clip a lesion too tangential to be clipped without it. However, this study did not compare conventional hemoclipping with hemoclipping using a cap because the cap was only used in cases in which conventional clipping had failed.
Collapse
Affiliation(s)
- J I Kim
- Department of Gastroenterology, Internal Medicine, The Catholic University of Korea, Seoul, Korea
| | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Abstract
The most common type of esophageal food-related foreign body is the meat bolus, which is frequently associated with underlying esophageal stenosis. Herein, we report two cases of meat bolus impaction associated with nutcracker esophagus. In the first case, the 63-year-old male patient had chest discomfort and swallowing difficulty after ingestion of butcher's meat. In the second case, the 55-year-old male patient had complained of swallowing difficulty after ingestion of chicken. In both cases, no pathologic findings were observed endoscopically after removal of the esophageal meat bolus. We performed esophageal manometry, which showed very high amplitudes of esophageal pressure in the mid- and distal esophagus. These findings were consistent with nutcracker esophagus. These cases show that esophageal motility disorder may be the cause of esophageal foreign body impaction, and esophageal manometry should be performed for evaluation of the cause of foreign body, especially in an endoscopically normal patient.
Collapse
Affiliation(s)
- H S Chae
- Department of Internal Medicine, Catholic University College of Medicine, Seoul, South Korea
| | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Abstract
The three-dimensional structures of Delta5-3-ketosteroid isomerases from two different bacterial species have been determined. The structures reveal an unusually apolar active site, in which each of several competitive inhibitors of the enzyme are held by two hydrogen bonds with the general acids Tyr14 and Asp99, and by hydrophobic interactions. The hydrogen bond between the Tyr14 hydroxyl and the C3 oxyanion of a transition-state analog is a low-barrier hydrogen bond, as indicated by a highly deshielded nuclear magnetic resonance. Structural and other biochemical studies have enabled the proposal of a detailed catalytic mechanism for Delta5-3-ketosteroid isomerase and provided a major thrust towards understanding the mechanism not only in chemical terms but also in energetics terms.
Collapse
Affiliation(s)
- N C Ha
- National Creative Research Initiative Center for Biomolecular Recognition, Pohang University of Science and Technology, Pohang, 790-784, Kyungbuk, South Korea
| | | | | | | |
Collapse
|
45
|
Lemmens P, Choi KY, Kaul EE, Geibel C, Becker K, Brenig W, Valenti R, Gros C, Johnsson M, Millet P, Mila F. Evidence for an unconventional magnetic instability in the spin-tetrahedra system Cu(2)Te(2)O(5)Br(2). Phys Rev Lett 2001; 87:227201. [PMID: 11736421 DOI: 10.1103/physrevlett.87.227201] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2001] [Indexed: 05/23/2023]
Abstract
Thermodynamic experiments as well as Raman scattering have been used to study the magnetic instabilities in the spin-tetrahedra systems Cu(2)Te(2)O(5)X(2), X = Cl and Br. While the phase transition observed in the Cl system at T(N) = 18.2 K is consistent with 3D antiferromagnetic ordering, the phase transition at T(o) = 11.4 K in the Br system has several unusual features. We propose an explanation in terms of weakly coupled tetrahedra with a singlet-triplet gap and low-lying singlets.
Collapse
Affiliation(s)
- P Lemmens
- 2. Physikalisches Institut, RWTH Aachen, D-56056 Aachen, Germany
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
46
|
Nam GH, Jang DS, Cha SS, Lee TH, Kim DH, Hong BH, Yun YS, Oh BH, Choi KY. Maintenance of alpha-helical structures by phenyl rings in the active-site tyrosine triad contributes to catalysis and stability of ketosteroid isomerase from Pseudomonas putida biotype B. Biochemistry 2001; 40:13529-37. [PMID: 11695900 DOI: 10.1021/bi015547k] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ketosteroid isomerase (KSI) from Pseudomonas putida biotype B is a homodimeric enzyme catalyzing an allylic rearrangement of Delta5-3-ketosteroids at rates comparable with the diffusion-controlled limit. The tyrosine triad (Tyr14.Tyr55.Tyr30) forming a hydrogen-bond network in the apolar active site of KSI has been characterized in an effort to identify the roles of the phenyl rings in catalysis, stability, and unfolding of the enzyme. The replacement of Tyr14, a catalytic residue, with serine resulted in a 33-fold decrease of kcat, while the replacements of Tyr30 and Tyr55 with serine decreased kcat by 4- and 51-fold, respectively. The large decrease of kcat for Y55S could be due to the structural perturbation of alpha-helix A3, which results in the reorientation of the active-site residues as judged by the crystal structure of Y55S determined at 2.2 A resolution. Consistent with the analysis of the Y55S crystal structure, the far-UV circular dichroism spectra of Y14S, Y30S, and Y55S indicated that the elimination of the phenyl ring of the tyrosine reduced significantly the content of alpha-helices. Urea-induced equilibrium unfolding experiments revealed that the DeltaG(U)H2O values of Y14S, Y30S, and Y55S were significantly decreased by 11.9, 13.7, and 9.5 kcal/mol, respectively, as compared with that of the wild type. A characterization of the unfolding kinetics based on PhiU-value analysis indicates that the interactions mediated by the tyrosine triad in the native state are very resistant to unfolding. Taken together, our results demonstrate that the internal packing by the phenyl rings in the active-site tyrosine triad contributes to the conformational stability and catalytic activity of KSI by maintaining the structural integrity of the alpha-helices.
Collapse
Affiliation(s)
- G H Nam
- Division of Molecular and Life Sciences National Research Laboratory of Protein Engineering, and National CRI Center for Biomolecular Recognition, Pohang University of Science and Technology, Pohang, 790-784, South Korea
| | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Choi KY, Kim YS, Choo GH, Kim JG, Suh IH. [2,13-Bis(acetamido)-5,16-dimethyl-2,6,13,17-tetraazatricyclo[16.4.0.07,12]docosane]copper(II) dichloride octahydrate. Acta Crystallogr C 2001; 57:1014-5. [PMID: 11588354 DOI: 10.1107/s0108270101004024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2001] [Accepted: 03/05/2001] [Indexed: 11/10/2022] Open
Abstract
The title compound, [Cu(C(24)H(46)N(6)O(2))]Cl(2).8H(2)O, contains a centrosymmetric cation, with the anions and water molecules on general sites. The coordination geometry around the Cu(II) ion is an axially elongated octahedron, with Cu-N distances of 2.0448 (17) and 2.0847 (17) A, and a Cu-O1 distance of 2.3138 (16) A.
Collapse
Affiliation(s)
- K Y Choi
- Department of Cultural Heritage Conservation Science, Kongju National University, Kongju 314-701, South Korea
| | | | | | | | | |
Collapse
|
48
|
Cho JH, Kim DH, Lee KJ, Kim DH, Choi KY. The role of Tyr248 probed by mutant bovine carboxypeptidase A: insight into the catalytic mechanism of carboxypeptidase A. Biochemistry 2001; 40:10197-203. [PMID: 11513597 DOI: 10.1021/bi010807j] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have investigated the function of Tyr248 using bovine wild-type CPA and its Y248F and Y248A mutants to find that the K(M) values were increased by 4.5-11-fold and the k(cat) values were reduced by 4.5-10.7-fold by the replacement of Tyr248 with Phe for the hydrolysis of hippuryl-L-Phe (HPA) and N-[3-(2-furyl)acryloyl]-Phe-Phe (FAPP), respectively. In the case of O-(trans-p-chlorocinnamoyl)-L-beta-phenyllactate (ClCPL), an ester substrate, the K(M) value was increased by 2.5-fold, and the k(cat) was reduced by 20-fold. The replacement of Tyr248 with Ala decreased the k(cat) values by about 18- and 237-fold for HPA and ClCPL, respectively, demonstrating that the aromatic ring of Tyr248 plays a critical role in the enzymic reaction. The increases of the K(M) values were only 6- and 5-fold for HPA and ClCPL, respectively. Thus, the present study indicates clearly that Tyr248 plays an important role not only in the binding of substrate but also in the enzymic hydrolysis. The kinetic results may be rationalized by the proposition that the phenolic hydroxyl of Tyr248 forms a hydrogen bond with the zinc-bound water molecule, causing further activation of the water molecule by reducing its pK(a) value. The pH dependency study of k(cat) values and the solvent isotope effects also support the proposition. A unified catalytic mechanism is proposed that can account for the different kinetic behavior observed in the CPA-catalyzed hydrolysis of peptide and ester substrates.
Collapse
Affiliation(s)
- J H Cho
- Department of Life Sciences and Chemistry, Division of Molecular and Life, Pohang University of Science and Technology, San 31 Hyoja-dong, Pohang 790-784, Korea
| | | | | | | | | |
Collapse
|
49
|
Affiliation(s)
- H S Chae
- Department of Internal Medicine and Surgery, Catholic University, College of Medicine, Seoul, South Korea
| | | | | | | | | | | | | | | |
Collapse
|
50
|
Choi G, Ha NC, Kim MS, Hong BH, Oh BH, Choi KY. Pseudoreversion of the catalytic activity of Y14F by the additional substitution(s) of tyrosine with phenylalanine in the hydrogen bond network of delta 5-3-ketosteroid isomerase from Pseudomonas putida biotype B. Biochemistry 2001; 40:6828-35. [PMID: 11389596 DOI: 10.1021/bi002767+] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Delta5-3-ketosteroid isomerase (KSI) from Pseudomonas putida Biotype B catalyzes the allylic isomerization of Delta5-3-ketosteroids to their conjugated Delta4-isomers via a dienolate intermediate. Two electrophilic catalysts, Tyr-14 and Asp-99, are involved in a hydrogen bond network that comprises Asp-99 Odelta2...O of Wat504...Tyr-14 Oeta...Tyr-55 Oeta.Tyr-30 Oeta in the active site of P. putida KSI. Even though neither Tyr-30 nor Tyr-55 plays an essential role in catalysis by the KSI, the catalytic activity of Y14F could be increased ca. 26-51-fold by the additional Y30F and/or Y55F mutation in the hydrogen bond network. To identify the structural basis for the pseudoreversion in the KSI, crystal structures of Y14F and Y14F/Y30F/Y55F have been determined at 1.8 and 2.0 A resolution, respectively. Comparisons of the two structures near the catalytic center indicate that the hydrogen bond between Asp-99 Odelta2 and C3-O of the steroid, which is perturbed by the Y14F mutation, can be partially restored to that in the wild-type enzyme by the additional Y30F/Y55F mutations. The kinetic parameters of the tyrosine mutants with the additional D99N or D99L mutation also support the idea that Asp-99 contributes to catalysis more efficiently in Y14F/Y30F/Y55F than in Y14F. In contrast to the catalytic mechanism of Y14F, the C4 proton of the steroid substrate was found to be transferred to the C6 position in Y14F/Y30F/Y55F with little exchange of the substrate 4beta-proton with a solvent deuterium based on the reaction rate in D2O. Taken together, our findings strongly suggest that the improvement in the catalytic activity of Y14F by the additional Y30F/Y55F mutations is due to the changes in the structural integrity at the catalytic site and the resulting restoration of the proton-transfer mechanism in Y14F/Y30F/Y55F.
Collapse
Affiliation(s)
- G Choi
- Division of Molecular and Life Sciences, Pohang University of Science and Technology, Pohang, Kyungbuk, South Korea
| | | | | | | | | | | |
Collapse
|