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Chae H, Ahn MS, Noh D, Nam H, Hong D. BALLU2: A Safe and Affordable Buoyancy Assisted Biped. Front Robot AI 2021; 8:730323. [PMID: 34957224 PMCID: PMC8692890 DOI: 10.3389/frobt.2021.730323] [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: 06/24/2021] [Accepted: 08/24/2021] [Indexed: 12/03/2022] Open
Abstract
This work presents the first full disclosure of BALLU, Buoyancy Assisted Lightweight Legged Unit, and describes the advantages and challenges of its concept, the hardware design of a new implementation (BALLU2), a motion analysis, and a data-driven walking controller. BALLU is a robot that never falls down due to the buoyancy provided by a set of helium balloons attached to the lightweight body, which solves many issues that hinder current robots from operating close to humans. The advantages gained also lead to the platform’s distinct difficulties caused by severe nonlinearities and external forces such as buoyancy and drag. The paper describes the nonconventional characteristics of BALLU as a legged robot and then gives an analysis of its unique behavior. Based on the analysis, a data-driven approach is proposed to achieve non-teleoperated walking: a statistical process using Spearman Correlation Coefficient is proposed to form low-dimensional state vectors from the simulation data, and an artificial neural network-based controller is trained on the same data. The controller is tested both on simulation and on real-world hardware. Its performance is assessed by observing the robot’s limit cycles and trajectories in the Cartesian coordinate. The controller generates periodic walking sequences in simulation as well as on the real-world robot even without additional transfer learning. It is also shown that the controller can deal with unseen conditions during the training phase. The resulting behavior not only shows the robustness of the controller but also implies that the proposed statistical process effectively extracts a state vector that is low-dimensional yet contains the essential information of the high-dimensional dynamics of BALLU’s walking.
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Affiliation(s)
- Hosik Chae
- Robotics and Mechanisms Laboratory (RoMeLa), Department of Mechanical and Aerospace Engineering, University of California, Los Angeles (UCLA), Los Angeles, CA, United States
| | - Min Sung Ahn
- Robotics and Mechanisms Laboratory (RoMeLa), Department of Mechanical and Aerospace Engineering, University of California, Los Angeles (UCLA), Los Angeles, CA, United States
| | - Donghun Noh
- Robotics and Mechanisms Laboratory (RoMeLa), Department of Mechanical and Aerospace Engineering, University of California, Los Angeles (UCLA), Los Angeles, CA, United States
| | - Hyunwoo Nam
- Robotics and Mechanisms Laboratory (RoMeLa), Department of Mechanical and Aerospace Engineering, University of California, Los Angeles (UCLA), Los Angeles, CA, United States
| | - Dennis Hong
- Robotics and Mechanisms Laboratory (RoMeLa), Department of Mechanical and Aerospace Engineering, University of California, Los Angeles (UCLA), Los Angeles, CA, United States
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Hooks J, Ahn MS, Yu J, Zhang X, Zhu T, Chae H, Hong D. ALPHRED: A Multi-Modal Operations Quadruped Robot for Package Delivery Applications. IEEE Robot Autom Lett 2020. [DOI: 10.1109/lra.2020.3007482] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Yoo BS, Ahn MS, Lee SJ, Son JW, Kim JY, Park SW. P783Guideline-directed therapy at discharge is important in patients with heart failure and atrial fibrillation. Eur Heart J 2019. [DOI: 10.1093/eurheartj/ehz747.0383] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background
There are limited and conflicting data regarding the prognostic implication of guideline-directed therapy, especially in heart failure (HF) patients with atrial fibrillation (AF). Thus, this study evaluated the relationship between guideline adherence to recommended therapy at discharge and relevant 60-day clinical outcomes in acute HF patients with AF having reduced ejection fraction (HFrEF) or preserved ejection fraction (HFpEF).
Methods and results
Of 5,625 acute HF patients in the Korean Acute Heart Failure Registry, 2,071 with documented AF (HFrEF, n=986; HFpEF, n=1,085) were separately analysed. A guideline adherence score was calculated for the prescription of angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, β-blockers, mineralocorticoid receptor antagonists, and anticoagulants. In HFrEF patients with AF, there was significant trend of increase in mortality (p for trend <0.001) and composite endpoint (p for trend = 0.002) according to guideline adherence. Poor adherence was associated with a significantly high risk of mortality (hazard ratio [HR], 4.75; 95% confidence interval [95% CI], 1.77–12.74) and composite endpoint (HR, 2.36; 95% CI, 1.33–4.18). In HFpEF patients with AF, there was a significant increasing trend for rehospitalization (p for trend = 0.04) and composite endpoint (p for trend = 0.03). However, the beneficial effect of good guideline adherence was statistically non-significant for all clinical outcomes
Conclusion
Better adherence to guidelines was associated with a better 60-day prognosis in both HFrEF and HFpEF patients with AF. However, the beneficial effect of guideline adherence was more pronounced in HFrEF patients with AF.
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Affiliation(s)
- B S Yoo
- Wonju College of Medicine, Yonsei University, Division of Cardiology, Department of Internal Medicin, Wonju, Korea (Republic of)
| | - M S Ahn
- Wonju College of Medicine, Yonsei University, Division of Cardiology, Department of Internal Medicin, Wonju, Korea (Republic of)
| | - S J Lee
- Wonju College of Medicine, Yonsei University, Division of Cardiology, Department of Internal Medicin, Wonju, Korea (Republic of)
| | - J W Son
- Wonju College of Medicine, Yonsei University, Division of Cardiology, Department of Internal Medicin, Wonju, Korea (Republic of)
| | - J Y Kim
- Wonju College of Medicine, Yonsei University, Division of Cardiology, Department of Internal Medicin, Wonju, Korea (Republic of)
| | - S W Park
- Wonju College of Medicine, Yonsei University, Division of Cardiology, Department of Internal Medicin, Wonju, Korea (Republic of)
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McGill SG, Yi S, Yi H, Ahn MS, Cho S, Liu K, Sun D, Lee B, Jeong H, Huh J, Hong D, Lee DD. Team THOR's Entry in the DARPA Robotics Challenge Finals 2015. J FIELD ROBOT 2016. [DOI: 10.1002/rob.21672] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Stephen G. McGill
- GRASP Lab University of Pennsylvania Philadelphia Pennsylvania 19104
| | - Seung‐Joon Yi
- GRASP Lab University of Pennsylvania Philadelphia Pennsylvania 19104
| | - Hak Yi
- School of Mechanical Engineering Kyungpook National University Daegu South Korea 41566
| | - Min Sung Ahn
- RoMeLa Lab University of California at Los Angeles Los Angeles California 90095
| | - Sanghyun Cho
- RoMeLa Lab University of California at Los Angeles Los Angeles California 90095
| | - Kevin Liu
- RoMeLa Lab University of California at Los Angeles Los Angeles California 90095
| | - Daniel Sun
- RoMeLa Lab University of California at Los Angeles Los Angeles California 90095
| | - Bhoram Lee
- GRASP Lab University of Pennsylvania Philadelphia Pennsylvania 19104
| | - Heejin Jeong
- GRASP Lab University of Pennsylvania Philadelphia Pennsylvania 19104
| | - Jinwook Huh
- GRASP Lab University of Pennsylvania Philadelphia Pennsylvania 19104
| | - Dennis Hong
- RoMeLa Lab University of California at Los Angeles Los Angeles California 90095
| | - Daniel D. Lee
- GRASP Lab University of Pennsylvania Philadelphia Pennsylvania 19104
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Shin DW, Shin JY, Oh SJ, Park JK, Yu H, Ahn MS, Bae KB, Hong KH, Ji YI. The Prognostic Value of Circumferential Resection Margin Involvement in Patients with Extraperitoneal Rectal Cancer. Am Surg 2016; 82:348-355. [PMID: 27097629] [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: 06/05/2023]
Abstract
The prognostic influence of circumferential resection margin (CRM) status in extraperitoneal rectal cancer probably differs from that of intraperitoneal rectal cancer because of its different anatomical and biological behaviors. However, previous reports have not provided the data focused on extraperitoneal rectal cancer. Therefore, the aim of this study was to examine the prognostic significance of the CRM status in patients with extraperitoneal rectal cancer. From January 2005 to December 2008, 248 patients were treated for extraperitoneal rectal cancer and enrolled in a prospectively collected database. Extraperitoneal rectal cancer was defined based on tumors located below the anterior peritoneal reflection, as determined intraoperatively by a surgeon. Cox model was used for multivariate analysis to examine risk factors of recurrence and mortality in the 248 patients, and multivariate logistic regression analysis was performed to identify predictors of recurrence and mortality in 135 patients with T3 rectal cancer. CRM involvement for extraperitoneal rectal cancer was present in 29 (11.7%) of the 248 patients, and was the identified predictor of local recurrence, overall recurrence, and death by multivariate Cox analysis. In the 135 patients with T3 cancer, CRM involvement was found to be associated with higher probability of local recurrence and mortality. In extraperitoneal rectal cancer, CRM involvement is an independent risk factor of recurrence and survival. Based on the results of the present study, it seems that CRM involvement in extraperitoneal rectal cancer is considered an indicator for (neo)adjuvant therapy rather than conventional TN status.
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Affiliation(s)
- Dong Woo Shin
- Department of Surgery, Haeundae Paik Hospital, College of Medicine, Inje University, Haeundae-ro, Haeundae-gu, Pusan, Korea
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Shin DW, Shin JY, Oh SJ, Park JK, Yu H, Ahn MS, Bae KB, Hong KH, Ji YI. The Prognostic Value of Circumferential Resection Margin Involvement in Patients with Extraperitoneal Rectal Cancer. Am Surg 2016. [DOI: 10.1177/000313481608200421] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The prognostic influence of circumferential resection margin (CRM) status in extraperitoneal rectal cancer probably differs from that of intraperitoneal rectal cancer because of its different anatomical and biological behaviors. However, previous reports have not provided the data focused on extraperitoneal rectal cancer. Therefore, the aim of this study was to examine the prognostic significance of the CRM status in patients with extraperitoneal rectal cancer. From January 2005 to December 2008, 248 patients were treated for extraperitoneal rectal cancer and enrolled in a pro-spectively collected database. Extraperitoneal rectal cancer was defined based on tumors located below the anterior peritoneal reflection, as determined intraoperatively by a surgeon. Cox model was used for multivariate analysis to examine risk factors of recurrence and mortality in the 248 patients, and multivariate logistic regression analysis was performed to identify predictors of recurrence and mortality in 135 patients with T3 rectal cancer. CRM involvement for extraperitoneal rectal cancer was present in 29 (11.7%) of the 248 patients, and was the identified predictor of local recurrence, overall recurrence, and death by multivariate Cox analysis. In the 135 patients with T3 cancer, CRM involvement was found to be associated with higher probability of local recurrence and mortality. In extraperitoneal rectal cancer, CRM involvement is an independent risk factor of recurrence and survival. Based on the results of the present study, it seems that CRM involvement in extraperitoneal rectal cancer is considered an indicator for (neo)adjuvant therapy rather than conventional TN status.
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Affiliation(s)
- Dong Woo Shin
- Department of Surgery, Haeundae Paik Hospital, College of Medicine, Inje University, Haeundae-ro, Haeundae-gu, Pusan, Korea
| | - Jin Yong Shin
- Department of Surgery, Haeundae Paik Hospital, College of Medicine, Inje University, Haeundae-ro, Haeundae-gu, Pusan, Korea
| | - Sung Jin Oh
- Department of Surgery, Haeundae Paik Hospital, College of Medicine, Inje University, Haeundae-ro, Haeundae-gu, Pusan, Korea
| | - Jong Kwon Park
- Department of Surgery, Haeundae Paik Hospital, College of Medicine, Inje University, Haeundae-ro, Haeundae-gu, Pusan, Korea
| | - Hyeon Yu
- Department of Surgery, Haeundae Paik Hospital, College of Medicine, Inje University, Haeundae-ro, Haeundae-gu, Pusan, Korea
| | - Min Sung Ahn
- Department of Surgery, Pusan Paik Hospital, College of Medicine, Inje University, Pusan, Korea
| | - Ki Beom Bae
- Department of Surgery, Pusan Paik Hospital, College of Medicine, Inje University, Pusan, Korea
| | - Kwan Hee Hong
- Department of Surgery, Pusan Paik Hospital, College of Medicine, Inje University, Pusan, Korea
| | - Yong Il Ji
- Department of Gynecology and Obstetrics, Haeundae Paik Hospital, College of Medicine, Inje University, Haeundae-ro, Haeundae-gu, Pusan, Korea
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8
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Seong Park J, Choi JH, Kang SY, Lee HW, Ahn MS, Cho SR, Jeong SH. Clinical significance of cryptic chromosomal translocations detected by multiplex RT-PCR in patients with acute leukemia. Int J Lab Hematol 2013; 36:e20-3. [PMID: 23910794 DOI: 10.1111/ijlh.12127] [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: 12/01/2022]
Affiliation(s)
- J Seong Park
- Departments of Hematology-Oncology, Ajou University School of Medicine, Suwon, Korea
| | - J-H Choi
- Departments of Hematology-Oncology, Ajou University School of Medicine, Suwon, Korea
| | - S Y Kang
- Departments of Hematology-Oncology, Ajou University School of Medicine, Suwon, Korea
| | - H W Lee
- Departments of Hematology-Oncology, Ajou University School of Medicine, Suwon, Korea
| | - M S Ahn
- Departments of Hematology-Oncology, Ajou University School of Medicine, Suwon, Korea
| | - S R Cho
- Departments of Laboratory Medicine, Ajou University School of Medicine, Suwon, Korea
| | - S H Jeong
- Departments of Hematology-Oncology, Ajou University School of Medicine, Suwon, Korea.
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Lee CK, Ahn MS, Lee EY, Shin JH, Cho YS, Ha HK, Yoo B, Moon HB. Acute abdominal pain in systemic lupus erythematosus: focus on lupus enteritis (gastrointestinal vasculitis). Ann Rheum Dis 2002; 61:547-50. [PMID: 12006332 PMCID: PMC1754133 DOI: 10.1136/ard.61.6.547] [Citation(s) in RCA: 143] [Impact Index Per Article: 6.5] [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: 02/07/2023]
Abstract
OBJECTIVE To determine the causes of acute abdominal pain in systemic lupus erythematosus (SLE) and to compare the clinical and laboratory data, especially antiphospholipid antibodies and the SLE Disease Activity Index (SLEDAI), between lupus enteritis (gastrointestinal vasculitis) and acute abdominal pain without lupus enteritis in patients with SLE. METHODS A retrospective study was carried out for all patients admitted with SLE from 1993 to March 2001. The SLEDAI and laboratory data were collected at the time of diagnosis of SLE and at the time of acute abdominal pain. Lupus enteritis (gastrointestinal vasculitis) was diagnosed by clinical investigation and abdominal computed tomographic findings. RESULTS Chart review identified 175 patients (20 male, 155 female) who had been admitted with SLE. Of these patients, 38 (22%) presented with acute abdominal pain. Lupus enteritis was the most common cause of acute abdominal pain. Patients were divided into three groups: group 1: lupus enteritis (n=17), group 2: acute abdominal pain without lupus enteritis (n=21), and group 3: SLE without acute abdominal pain (n=137). There was no difference in age and sex among the three groups. Antiphospholipid, anti-RNP, anti-Sm, anti-Ro, and anti-La antibodies did not differ among the three groups. There was no difference in the SLEDAI at the time of diagnosis and at the time of acute abdominal pain between groups 1 and 2. Complement, erythrocyte sedimentation rate, C reactive protein, and anti-dsDNA measured at the time of acute abdominal pain did not differ between groups 1 and 2. A drop in the white blood cell count at the time of abdominal pain was more prominent in group 1 than group 2. In lupus enteritis, the jejunum and ileum were the sites most commonly affected. Rectal involvement was rare. Even though four patients relapsed, all the patients with lupus enteritis, including those who relapsed, responded well to corticosteroid. CONCLUSION Lupus enteritis is the most common cause of acute abdominal pain in SLE. All patients with lupus enteritis responded well to a high dose of a corticosteroid without surgical intervention. The SLEDAI and laboratory data, except leucopenia, do not correlate with the occurrence of lupus enteritis.
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Affiliation(s)
- C-K Lee
- Division of Allergy and Rheumatology, Department of Internal Medicine, Asan Medical Centre, Seoul, Korea
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10
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Abstract
The basic principles of successful total nasal reconstruction include providing a sufficient amount of tissue coverage, creating an adequate structural framework, and fashioning a viable inner lining. Relative uniformity of opinion exists regarding sources for tissue coverage and nasal lining. A variety of options exists, however, regarding the type of material used for nasal framework. Alloplastic metals, such as vitallium or titanium mesh, combined with autogenous soft tissue coverage, are reliable alternatives for use in total nasal reconstruction.
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Affiliation(s)
- M S Ahn
- Department of Otolaryngology-Head and Neck Surgery, Division of Facial Plastic and Reconstructive Surgery, University of California at San Francisco, San Francisco, California, USA
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11
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Miller PJ, Levine J, Ahn MS, Maas CS, Constantinides M. Softform for facial rejuvenation: historical review, operative techniques, and recent advances. Facial Plast Surg 2002; 16:23-8. [PMID: 11802342] [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: 02/23/2023] Open
Abstract
The deep nasolabial fold and other facial furrows and wrinkles have challenged the facial plastic surgeon. A variety of techniques have been used in the past to correct these troublesome defects. Advances in the last five years in new materials and design have created a subcutaneous implant that has excellent properties. This article reviews the development and use of Softform facial implant.
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Affiliation(s)
- P J Miller
- Division of Facial Plastic and Reconstructive Surgery, Department of Otolaryngology, New York University School of Medicine, New York, NY, USA
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Abstract
We report the first case in the English literature of an intramural duodenal hematoma presenting as a complication of Helicobacter pylori-induced peptic ulcer disease. Intramural duodenal hematomas have been previously described in patients-usually in the setting of blunt trauma, postendoscopic biopsy, gastrostomy placement, and hemostatic therapy and in patients with a coagulopathy or bleeding diathesis-but not as a presentation of peptic ulcer disease. It is important to recognize this complication, as surgical management may benefit patients with a duodenal hematoma.
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Affiliation(s)
- M S Ahn
- Department of Medicine, University of California, San Diego, California, U.S.A
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Abstract
Retroperitoneal fibrosis is a rare disease characterized by the formation of dense plaque of fibrous tissue covering the retroperitoneal structures. This disease is commonly presented as ureteral obstruction, but the involvement of duodenum is rare. We report a case of retroperitoneal fibrosis which was complicated with duodenal stenosis and was successfully treated with corticosteroids. A 58-yr-old man, who had history of aorto-iliac bypass graft due to arteriosclerosis obliterans with infrarenal aortic occlusion was admitted to the hospital with abdominal pain and a mass. Abdominal CT scan revealed the periaortic soft tissue mass encircling grafted aorta and stenosis of duodenal third portion. Retroperitoneal fibrosis with duodenal stenosis was diagnosed and prednisolone therapy was initiated. Follow-up CT scan showed that the patient responded to prednisolone therapy with eased pain, shrinking periaortic mass, and reduced duodenal stenosis.
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Affiliation(s)
- B M Jun
- Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
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Kim SJ, Ha J, Jung IM, Ahn MS, Kim M, Lee HS, Cheong HI, Choi Y. Recurrent focal segmental glomerulosclerosis following renal transplantation in Korean pediatric patients. Pediatr Transplant 2001; 5:105-11. [PMID: 11328548 DOI: 10.1034/j.1399-3046.2001.005002105.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [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: 11/23/2022]
Abstract
The recurrence of focal segmental glomerulosclerosis (FSGS) in transplants is a well-known problem in pediatric renal transplantation (Tx). Recently, the race of the recipient was recognized as a major variable associated with disease recurrence. In view of this finding, we report on our single-center experience of FSGS recurrence in Korean children, an ethnically homogeneous Far East Asian population. Clinical records and renal biopsy specimens, both native and graft, were reviewed for all pediatric renal Txs (recipient age < or = 18 yr) performed at Seoul National University Hospital from 1984 to 1999. Twenty-two children with primary FSGS received 22 allografts for renal replacement. The mean age of disease onset in these patients was 5.9 yr. The grafts were from 12 living-related, six living-unrelated, and four cadaveric donors, and all recipients were immunosuppressed with cyclosporin A (CsA)-based regimens. Post-transplant recurrence of FSGS was confirmed in nine patients (41%). Long-term graft survival in recurrent and non-recurrent groups was not significantly different. Risk factor analysis showed that patients with a disease duration shorter than 48 months (odds ratio 11.7, 95% CI 1.53-89.1) and a glomerulosclerosis percentage of < 55% by renal biopsy (odds ratio 16.0, 95% CI 1.45-176) were at greater risk of disease recurrence. These results suggest that Korean children are similar to non-African-American youngsters in the USA and Europe with respect to post-transplant recurrence of FSGS. The same may be true of other Far Eastern Asian children.
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Affiliation(s)
- S J Kim
- Department of Surgery, Seoul National University Hospital, 28 Yongon-dong, Chongno-gu, Seoul, 110-460, Korea.
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Affiliation(s)
- S K Min
- Department of Surgery, Seoul National University College of Medicine, Seoul, South Korea
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Kwon SY, Ahn MS, Chang HJ. Clinical significance of hepatitis C virus infection to alcoholics with cirrhosis in Korea. J Gastroenterol Hepatol 2000; 15:1282-6. [PMID: 11129222] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
BACKGROUND/METHODS To investigate the prevalence and clinical significance of hepatitis C virus (HCV) infection and its relationship with the development of hepatocellular carcinoma (HCC), 162 consecutive alcoholic patients with cirrhosis were studied. Alcohol intake and parenteral risk factors were investigated by interview using a questionnaire. All patients had consumed at least 80 g alcohol/day for at least the past 5 years. Sera were tested for anti-HCV using a third-generation enzyme immunoassay (EIA), hepatitis B s antigen (HBsAg), anti-HBs, anti-HBc and anti-HIV. Serum HCV-RNA was detected by a one-tube reverse transcription-polymerase chain reaction (RT-PCR) method. Patients were classified into three groups accroding to the presence or absence of viral markers: (i) cases without anti-HCV or HBsAg (group A); (ii) cases with HBsAg only (group B); and (iii) cases with anti-HCV only (group C). Demographic and clinical findings were compared among the three groups. RESULTS Anti-HCV was present in 17 cases (10.5%) and HBsAg was present in 47 cases (29%). No patient had both anti-HCV and HBsAg. Group C subjects were the oldest, but the duration of drinking in this group was similar to that of group A. There was no significant difference in the daily alcohol intake among the three groups. Previous surgical operations and tattooing were more frequent in group C. Only one patient in group C was an intravenous drug user. The combined rate of HCC was significantly higher in groups B and C than in groups A (34, 23.5 and 6.1%, respectively). Laboratory data showed a higher platelet count, higher albumin level, lower bilirubin level and lower aspartate aminotransferase/alanine aminotransferase ratio in group C patients than in the other two groups. Hepatitis C virus RNA was detected in 14 of 85 cases tested (16.5%), in 11 of 12 cases (91.7%) with anti-HCV and in three of 73 cases (4.1%) without anti-HCV. CONCLUSIONS Hepatitis C virus infection is frequent in alcoholic patients with cirrhosis in Korea. Hepatitis C virus, as well as hepatitis B virus, infection may have a synergistic effect on the development of HCC in alcoholic patients.
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Affiliation(s)
- S Y Kwon
- Department of Internal Medicine, National Medical Center, Seoul, Korea.
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Park CS, Krishna G, Ahn MS, Kang JH, Chung WG, Kim DJ, Hwang HK, Lee JN, Paik SG, Cha YN. Differential and constitutive expression of neuronal, inducible, and endothelial nitric oxide synthase mRNAs and proteins in pathologically normal human tissues. Nitric Oxide 2000; 4:459-71. [PMID: 11020335 DOI: 10.1006/niox.2000.0300] [Citation(s) in RCA: 36] [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: 11/22/2022]
Abstract
Nitric oxide (NO) is produced by NO synthases (nNOS, iNOS, and eNOS) expressed in various human tissues and depending on the amount of NO produced in each tissue, the physiological function of NO is determined. However, due to the difficulty in obtaining normal human tissues, little is known about the basal levels of each of the three NOS mRNAsand proteins expressed constitutively in various human tissues. Results of the present study indicate that the basal levels of each of the three NOS mRNAs and proteins expressed in various regions of brain and peripheral tissues are different both in their sizes and in their contents. In Northern blot analysis, two different-sized mRNAs were found for each NOS isozymes: for the nNOS, approximately 12 and <12 kb mRNAs; for the iNOS, 4.2 and 4.5 kb mRNAs; for the eNOS, 4.2 and 4.4 kb mRNAs. In the Western blot, several different-sized NOS proteins were detected ( approximately 160, approximately 140, and approximately 130 kDa for nNOS; approximately 130 kDa for iNOS and eNOS) with tissue-specific expression patterns. These differential expression patterns of NOS mRNAs and proteins were caused by alternative splicing in the open-reading frame, and 5'- and/or 3'-untranslated regions of NOS mRNAs. These results suggest that regulation for differential expression of the three NOS genes in various human tissues may occur by alternative splicing of the NOS mRNAs in tissue-specific patterns.
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Affiliation(s)
- C S Park
- Department of Pharmacology and Toxicology, Inha University, Inchon, Korea
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Abstract
The objective of this study was to determine whether brow elevation occurs as a result of paralysis of brow depressors after botulinum toxin A injection. The study's design was a prospective case series with pretreatment and posttreatment outcome evaluation with statistical analysis at a university-based division of facial plastic surgery private clinic. Twenty-two patients of a consecutive sample desiring a cosmetic enhancement underwent injection of botulinum toxin A directed to brow depressors. Injections consisted of 7 to 10 units of botulinum toxin A (Botox, Allergan, Irvine, Calif.) into selected brow depressor muscle (lateral orbicularis oculi) bilaterally. No patients withdrew for adverse effects. All patients were evaluated 2 weeks after treatment. The outcomes were measured by change in brow elevation along vertical axis extending from both midpupil and lateral canthus to the caudal row of brow hairs with eyes at neutral gaze and the head at Frankfort plane. Preintervention and postintervention brow height was measured by the primary clinical investigator. The average brow elevation from the midpupil observed after selected injection of brow depressors with botulinum toxin A was 1.02 mm (p = 0.038). The average brow elevation from the lateral canthus observed after selected injection of brow depressors with botulinum toxin A was 4.83 mm (p<0.0001). Significant temporal brow elevation occurs as the result of paralysis of brow depressors by using botulinum toxin A injection. This procedure may be considered an alternative to surgical brow elevation.
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Affiliation(s)
- M S Ahn
- Division of Facial Plastic Surgery at the University of California at San Francisco, USA
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Abstract
BACKGROUND The most common neoplasm of the parotid gland is the pleomorphic adenoma. The familial occurrence of such tumors arising within the parotid gland is rare, with only 3 previous reports in the literature. Bilateral synchronous pleomorphic adenomas of the parotid gland are also uncommon. We report 2 siblings with pleomorphic adenomas of the parotid gland, 1 of whom had bilateral synchronous mixed tumors. Patients and Methods Chromosomal analysis of tumor cells from the sibling with bilateral adenomas revealed the translocation t(3;12)(p21;q15). Chromosome 12q breakpoints have previously been identified in a wide variety of solid tumors including pleomorphic adenomas of the parotid gland. CONCLUSIONS We discuss bilateral mixed tumors, familial parotid tumors, and the potential for a genetic predisposition for the recurrence of such parotid tumors, as suggested by characteristic chromosomal translocations associated with mixed tumors.
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Affiliation(s)
- M S Ahn
- Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, 400 Parnassus Ave, Suite A730, San Francisco, California 94117, USA
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20
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Yun SW, Choi EK, Ju WK, Ahn MS, Carp RI, Wisniewski HM, Kim YS. Extensive degeneration of catecholaminergic neurons to scrapie agent 87V in the brains of IM mice. Mol Chem Neuropathol 1998; 34:121-32. [PMID: 10327412 DOI: 10.1007/bf02815074] [Citation(s) in RCA: 11] [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] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Scrapie is a degenerative disease of the central nervous system of sheep and goats. The causative agent has been passaged to a number of laboratory species, including mice and hamster. Amyloid plaque formation and vacuolation, the signs of senile dementia, are found in the brains of mice infected with 87V scrapie agent. Dopamine (DA) and norepinephrine (NE) concentrations in the brains of scrapie-infected mice were measured with high-performance liquid chromatography-electrochemical detector (HPLC-ECD). A significant decrease in NE level was exhibited in all regions tested, whereas the level of DA decreased significantly only in cerebral cortex. Immunohistochemistry was used to examine immunoreactive catecholamine neurons in substantia nigra and locus ceruleus using antisera against tyrosine hydroxylase (TH). The population of TH-immunoreactive neurons in the substantia nigra and locus ceruleus were significantly decreased in scrapie-infected mice compared to controls. These data suggest that both the noradrenergic and dopaminergic system are sensitive to the action of scrapie agent 87V and that changes in the catecholamine levels in the brains of scrapie-infected mice may contribute to some of the clinical symptoms of the diseases, such as ataxia and apraxia.
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Affiliation(s)
- S W Yun
- Institute of Environment and Life Science, College of Medicine, Hallym University, Chunchon, Korea
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21
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Abstract
The vast majority of cerebellopontine angle (CPA) tumors are extraaxial masses arising from either the eighth nerve (acoustic neuroma) or meninges (meningioma). Rarely, a tumor that arises from the brain parenchyma may protrude laterally to present with a clinical and radiographic picture simulating that of the much more common extraaxial lesions. Three individuals with CPA lesions that ultimately proved at operation to be exophytic brain tumors (pontine medulloblastoma, cerebellar astrocytoma, and fourth ventricular ependymoma) are described. The clinical manifestations of these lesions, although not entirely typical, fell well within the possible range of presentation of benign tumors primary to the CPA. In two of these cases the tumor actually penetrated into the internal auditory canal. As the optimal management strategy for treating parenchymal tumors differs substantially from that for extraaxial lesions, it is essential that the surgeon have a preoperative awareness of the lesion's nature before embarking on a surgical endeavor. Critical to arriving at the correct diagnosis is the close examination of preoperative imaging studies. The clinician should be alerted to the possibility that a CPA tumor is of intraaxial origin when the preoperative magnetic resonance imaging scan shows 1) blurring of the margin between the tumor and brainstem or cerebellum; 2) a degree of peritumoral hyperintensity on T2-weighted scans disproportionate to the size of the extraaxial mass; and 3) dilation of the lateral recess of the fourth ventricle.
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Affiliation(s)
- M S Ahn
- Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco 94117, USA
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22
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Ahn MS, Jackler RK, Lustig LR. The early history of the neurofibromatosis. Evolution of the concept of neurofibromatosis type 2. Arch Otolaryngol Head Neck Surg 1996; 122:1240-9. [PMID: 8906061 DOI: 10.1001/archotol.1996.01890230086016] [Citation(s) in RCA: 27] [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] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Although neurofibromatosis (NF) became widely recognized as a pathologic entity in the late 19th century, only relatively recently has a clear distinction been made between its generalized form and the central variety. The latter form is typified by bilateral acoustic neuromas (ANs), which may be accompanied by other intracranial tumors, in particular, meningiomas. Up until almost the current era, confusion regarding the protean manifestations of the 2 types of NF existed in the minds of clinicians and in the literature. In 1987, a consensus panel of the National Institutes of Health differentiated the clinical manifestations associated with classic von Recklinghausen syndrome from those of the predominantly intracranial subtype and they were subsequently deemed NF type 1 (NF-1) and NF type 2 (NF-2), respectively. During the last few years, the genetic flaws that underlie these 2 syndromes have been elucidated, revealing that their origins lie in defects on separate chromosomes. The early literature on the subject included repeated descriptions of patients with manifestations typical of NF-2. The investigators, however, considered the intracranial lesions to be merely 1 facet of the generalized form of the disease. A few prescient individuals, however, demonstrated an appreciation for the distinguishing characteristics between these superficially similar, yet quite different, syndromes. The goals of this article are to trace the evolution of the concept of NF-2 as a distinct clinical entity from NF-1 and to assess the early awareness of and attitudes toward bilateral ANs, familial ANs, and ANs associated with other intracranial tumors.
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Affiliation(s)
- M S Ahn
- Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, USA
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23
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Ahn MS, Ha J, Yun IJ, Kim S, Lee JS, Kim S, Han JS, Ahn C, Choi Y, Cheong HI, Kim ST, Kim SJ. To keep a stable therapeutic level of cyclosporine during the early posttransplant period is important in graft survival. Transplant Proc 1996; 28:1316-7. [PMID: 8658675] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- M S Ahn
- Department of Surgery, Seoul National University Hospital, Korea
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24
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Abstract
Glutathione (GSH) is a potent endogenous antioxidant that protects major organs from oxidant injury. However, present nutrition regimens may inadequately support tissue stores of this tripeptide during critical illness. To determine whether GSH reserves can be enhanced in vivo with intravenous (IV) supplements, rats underwent central venous catheterization, were given chow and water ad libitum during a 2-day recovery period, and were then randomized to receive one of three treatments as an IV bolus: (1) dextrose, (2) glutathione (GSH), or (3) glutathione monoethyl ester. GSH monoethyl ester is transported into cells more easily than is GSH. Tissue and plasma samples were analyzed for GSH at 2 and 4 hours after drug administration. Liver, renal, and ileal mucosal GSH were significantly increased in the GSH-monoethyl ester rats compared with dextrose-treated animals. In addition, plasma GSH was dramatically increased after monoester injection. In contrast, GSH administration depressed liver GSH stores and did not significantly affect GSH concentration in the other organs analyzed. Plasma GSH concentration was elevated 2 hours after GSH administration. We conclude that: (1) the monoethyl ester of glutathione can be used in vivo to enhance tissue and plasma GSH concentration and (2) IV GSH administration does not significantly increase tissue GSH levels and may paradoxically depress hepatic GSH in normal rats. Because the malnourished and critically ill are likely to have depleted GSH stores, nutrition strategies that include the provision of GSH monoester may lend additional support to those organs that are at risk for injury from oxygen free radicals during catabolic states.
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Affiliation(s)
- M K Robinson
- Department of Surgery, Brigham and Women's Hospital/Harvard Medical School, Boston, Massachusetts 02115
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25
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Mitchell JB, DeGraff W, Kaufman D, Krishna MC, Samuni A, Finkelstein E, Ahn MS, Hahn SM, Gamson J, Russo A. Inhibition of oxygen-dependent radiation-induced damage by the nitroxide superoxide dismutase mimic, tempol. Arch Biochem Biophys 1991; 289:62-70. [PMID: 1654848 DOI: 10.1016/0003-9861(91)90442-l] [Citation(s) in RCA: 173] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Stable nitroxide radicals have been previously shown to function as superoxide dismutase (SOD)2 mimics and to protect mammalian cells against superoxide and hydrogen peroxide-mediated oxidative stress. These unique characteristics suggested that nitroxides, such as 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (Tempol), might protect mammalian cells against ionizing radiation. Treating Chinese hamster cells under aerobic conditions with 5, 10, 50, and 100 mM Tempol 10 min prior to X-rays resulted in radiation protection factors of 1.25, 1.30, 2.1, and 2.5, respectively. However, the reduced form of Tempol afforded no protection. Tempol treatment under hypoxic conditions did not provide radioprotection. Aerobic X-ray protection by Tempol could not be attributed to the induction of intracellular hypoxia, increase in intracellular glutathione, or induction of intracellular SOD mRNA. Tempol thus represents a new class of non-thiol-containing radiation protectors, which may be useful in elucidating the mechanism(s) of radiation-induced cellular damage and may have broad applications in protecting against oxidative stress.
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Affiliation(s)
- J B Mitchell
- Radiobiology Section, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
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26
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Abstract
Superoxide dismutase (SOD) is an enzyme that detoxifies superoxide (O2.-), a potentially toxic oxygen-derived species. Attempts to increase intracellular concentrations of SOD by direct application are complicated because SOD, being a relatively large molecule, does not readily cross cell membranes. We have identified a set of stable nitroxides that possess SOD-like activity, have the advantage of being low molecular weight, membrane permeable, and metal independent, and at pH 7.0 have reaction rate constants with O2.- ranging from 1.1 x 10(3) to 1.3 x 10(6) M-1 s-1. These SOD mimics protect mammalian cells from damage induced by hypoxanthine/xanthine oxidase and H2O2, although they exhibit no catalase-like activity. In addition, the nitroxide SOD mimics rapidly oxidize DNA-FeII and thus may interrupt the Fenton reaction and prevent formation of deleterious OH radicals and/or higher oxidation states of metal ions. Whether by SOD-like activity and/or interception of an electron from redox-active metal ions they protect cells from oxidative stress and may have use in basic and applied biological studies.
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Affiliation(s)
- J B Mitchell
- Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
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27
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Abstract
Intraventricular or epidural injection of morphine through implantable infusion devices was used for severe pain in 50 patients with advanced cancer, arachnoiditis, or spinal injury. Intraventricular catheter was inserted for injection of morphine in 21 patients, 29 were treated through epidural infusion. For the evaluation of results the multimodal evoked potential (MEP) has been obtained before and after each treatment. 80% of the patients experienced good results. No significant side effects have been noted in patients with either epidural or intraventricular injection of morphine. These may be excellent methods for pain control in well selected patients.
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Affiliation(s)
- C R Choi
- Department of Neurosurgery, St. Mary's Hospital, Catholic University Medical College, Seoul, Korea
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28
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Hakuba A, Komiyama M, Tsujimoto T, Ahn MS, Nishimura S, Ohta T, Kitano H. Transuncodiscal approach to dumbbell tumors of the cervical spinal canal. J Neurosurg 1984; 61:1100-6. [PMID: 6502239 DOI: 10.3171/jns.1984.61.6.1100] [Citation(s) in RCA: 65] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A combined anterior and lateral approach to the anterior cervical spinal canal with fusion was performed on five patients with cervical dumbbell-shaped tumors. The procedure consists of anterior discectomy and ipsilateral uncectomy, and removal of the posterolateral corners and posterior transverse ridges of the upper and lower vertebral bodies at the level of the tumor. In the case of a large tumor in the spinal canal, additional removal of a limited segment from the lateral part of the vertebral body was performed. The bone defect was filled with a T-shaped iliac bone graft. Two vertebral bodies were fused in each case. The highest level of the operation was C-2 and the lowest was T-1. The authors believe that any cervical dumbbell-shaped tumor below the C-2 level can be removed via an anterolateral approach as long as no more than three levels of the spine are involved.
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