Publications by authors named "Yong Koo Kang"

39 Publications

Multiple-Session Subthreshold Micropulse Laser Therapy for Exudative Perifoveal Vascular Anomalous Complex: a case report.

Retin Cases Brief Rep 2021 Jul 16. Epub 2021 Jul 16.

Department of Ophthalmology, Kyungpook National University Hospital, Kyungpook National University School of Medicine, Daegu, South Korea.

Purpose: To report a case of exudative perifoveal vascular anomalous complex treated with a 532 nm subthreshold micropulse laser unresponsive to intravitreal injections.

Methods: A case report.

Results: A 65-year-old woman presented with blurred vision in left eye for 1 month. An isolated perifoveal aneurysm surrounded by retinal hemorrhages and hard exudates was revealed in fundus examination and optical coherent tomography showed a round lesion with a hyperreflective wall, subretinal fluid, and an intraretinal cyst. She was diagnosed with exudative perifoveal vascular anomalous complex and received 4 intravitreal injections. However, her best-corrected visual acuity decreased and an aneurysmal lesion with macular edema persisted for approximately 6 months. We applied 3 sessions of 532 nm subthreshold micropulse laser therapy around the aneurysm because the intravitreal injection treatment was ineffective. Since the last session, macular edema was disappeared and the involuted lesion remained substantially stable without recurrence and her best-corrected visual acuity improved without visual field defect.

Conclusion: To our knowledge, this is the first report of a successful subthreshold micropulse laser treatment for an exudative perifoveal vascular anomalous complex lesion and it could be a safe and effective method for the patient unresponsive to intravitreal injections.
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http://dx.doi.org/10.1097/ICB.0000000000001181DOI Listing
July 2021

Long-Term Effect of Silicone Oil Tamponade for Postoperative and Posttraumatic Bacterial Endophthalmitis.

J Ophthalmol 2021 1;2021:6658281. Epub 2021 Feb 1.

Department of Ophthalmology, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea.

Purpose: To compare clinical features and microbial profiles, treatment outcomes, and prognostic factors of the eyes between postoperative and posttraumatic bacterial endophthalmitis after pars plana vitrectomy (PPV) with silicone oil (SO) tamponade.

Methods: Overall, 57 eyes of 57 patients who diagnosed exogenous bacterial endophthalmitis and underwent PPV with SO tamponade between 2000 and 2019 were reviewed. Causative microorganisms, culture positivity, change of mean best-corrected visual acuity (BCVA), and course of treatment were investigated between postoperative and posttraumatic groups, and relevant factors were analyzed according to the final BCVA.

Results: The mean BCVA change was not significantly different between groups. The positive rate of microorganisms was significantly higher in the postoperative group. The mean time to surgery over 48 hours, initial BCVA worse than hand motion, and additional surgery after initial vitrectomy were correlated with poor final BCVA worse than 20/200. There was significantly achieved final BCVA 20/200 or better in the and group than the and group.

Conclusion: PPV with SO tamponade may be an effective surgical treatment strategy for exogenous bacterial endophthalmitis. Final visual outcomes were not significantly different between postoperative and posttraumatic groups, and the mean time to surgery, initial visual acuity, additional surgery, and type of microorganism are significantly related to visual prognosis.
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http://dx.doi.org/10.1155/2021/6658281DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7870316PMC
February 2021

Germline Mutations for Novel Candidate Predisposition Genes in Sporadic Schwannomatosis.

Clin Orthop Relat Res 2020 11;478(11):2442-2450

K. B. Chang, M. W. Joo, Department of Orthopaedic Surgery, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.

Background: Schwannomatosis is a late-onset tumor predisposition syndrome associated with the development of many different types of malignancies. A relevant genetic mechanism can be explained by three mutational events. The first-hit mutation is a germline mutation, and the SMARCB1 mutation on chromosome 22 is the most well-known genetic abnormality in patients with schwannomatosis. LZTR1 is another major predisposing gene in 22q-related schwannomatosis that lacks SMARCB1 variants. Although these two variants account for the occurrence of most familiar schwannomatoses, the genetic causes of sporadic schwannomatosis for the most part remain unknown. Therefore, current molecular diagnostic criteria cannot completely explain the basis of this disease. The common genetic background between schwannomatosis and other related malignant tumors is also unclear. Moreover, it is not easy to explain various clinical manifestations by only two known mutations. QUESTION/PURPOSES: (1) Are there important sequences outside the SMARCB1 or LZTR1 region on chromosome 22 that might carry a first-hit mutational predisposition to sporadic schwannomatosis? Or are there alternative evolutionarily conserved loci that might carry a first-hit mutational predisposition? (2) Is the age of disease onset associated to such genetic variants?

Methods: This study was a retrospective chart review and prospective genetic study on patients with schwannomatosis who were treated surgically. The clinical criteria to diagnose schwannomatosis were as follows: (1) histologically proven nonvestibular schwannomas; (2) no evidence of vestibular schwannomas on 3-mm brain MRI. A total of 21 patients were treated between March 2006 and June 2015. Since nine patients did not visit the outpatient clinic during the recruitment period, we obtained blood samples from 12 patients with schwannomatosis for a genetic analysis. After two patients were excluded because of their family history of schwannomatosis, genetic analyses were finally performed on 10 patients. Then, those with NF2, SMARCB1 or LZTR1 variants were screened by whole exome sequencing. All 10 patients passed our screening strategy. There were eight men and two women, with a median (range) age of 43 years (24 to 66) at the time of diagnosis. To select candidate genes, common ethnic variants and frequent mutations in in-house exome sequencing data were removed to exclude the population-specific polymorphisms not found in other population and to generalize the findings. Frameshift, nonsense, and splice-site variants were deemed pathogenic. Missense variants were classified as potentially pathogenic, variants of uncertain significance, or benign using in silico (via computer simulation) prediction algorithms, Sorting Intolerant From Tolerant (SIFT), Polymorphism Phenotyping v2 (PolyPhen-2), and Combined Annotation Dependent Depletion (CADD). A variant was considered potentially pathogenic if two or more algorithms predicted the variant to be damaging and benign if none considered it damaging. Then, potentially pathogenic variants only in the genes associated with cancer-predisposition or DNA damage repair were classified as the pathogenic candidate variants of sporadic schwannomatosis. The predictions for pathogenic candidate variants were checked again on Clinical Interpretation of Genetic Variants (InterVar) based on the American College of Medical Genetics guidelines and validated against Mendelian clinically applicable pathogenicity scores (M-CAP scores).

Results: We detected 26 variants; 13 variants across 10 genes were predicted to be pathogenic and found in seven patients, two each in ARID1A, PTCH2, and NOTCH2 and one each in MSH6, ALPK2, MGMT, NOTCH1, CIC, TSC2, and CDKN2A. One frameshift deletion in PTCH2 met the criteria for pathogenic or likely pathogenic classification, as recommended by the American College of Medical Genetics guidelines. Six missense mutations were classified as possibly pathogenic variants based on M-CAP scores. Four predicted pathogenic missense variants were detected in DNA damage repair (DDR) genes. Three DDR genes were affected: ARID1A, MGMT, and MSH6. Among the nine predicted pathogenic mutations detected in known cancer-predisposing genes, one was a frameshift deletion and the others were missense mutations. Seven tumor suppressor genes were involved: PTCH2, ALPK2, CIC, NOTCH1, NOTCH2, TSC2, and CDKN2A. One patient with multiple pathogenic variants in two DDR genes, ARID1A and MSH6, received a schwannomatosis diagnosis at 33 years old. Each of the other patients who had single variants in the DDR gene received their diagnoses at 41 years of age. The age at diagnosis was 40 years or older in patients with variants in cancer-predisposing genes, except for one patient who had multiple variants in TSC2 and CDKN2A. The carrier of those variants received the diagnosis at 24 years old.

Conclusions: This study identified first-hit candidate mutations predisposing patients to schwannomatosis that were not related to SMARCB1 or LZTR1 variations in a cohort of patients with sporadic schwannomatosis. Patients with sporadic schwannomatosis without SMARCB1 or LZTR1 genetic variation may have developed the disease because of genomic variants related to cancer initiation in areas other than chromosome 22. Seven of 10 patients had predicted pathogenic germline mutations in DDR and cancer predisposition genes. We detected multiple cancer-related mutations in each patient. The age at the time schwannomatosis was diagnosed might be associated with a combination of variants and characteristics of the genes containing the variants; however, we did not have enough patients to confirm this association.

Clinical Relevance: The germline mutations identified in this study and the ideas related to the age of disease onset may provide potential candidate variants for future research on sporadic schwannomatosis and help to revise the current clinical and molecular diagnostic criteria. Further in vivo and in vitro studies are needed for these variants.
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http://dx.doi.org/10.1097/CORR.0000000000001239DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7571934PMC
November 2020

Subthreshold Micropulse Yellow Laser (577 nm) for Idiopathic Macular Telangiectasia Type 1 Resistant to Intravitreal Injection.

Korean J Ophthalmol 2020 04;34(2):168-169

Department of Ophthalmology, Kyungpook National University School of Medicine, Daegu, Korea.

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http://dx.doi.org/10.3341/kjo.2019.0071DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7105782PMC
April 2020

Incidence and treatment outcomes of secondary epiretinal membrane following intravitreal injection for diabetic macular edema.

Sci Rep 2020 01 17;10(1):528. Epub 2020 Jan 17.

Department of Ophthalmology, Kyungpook National University School of Medicine, Daegu, 41944, Korea.

The purpose of this study was to investigate the incidence of secondary epiretinal membrane (ERM) after intravitreal injection and the effect of ERM on visual acuity and central macular thickness (CMT) in patients with diabetic macular edema (DME). We included 147 eyes of 95 patients over 18 years old who were diagnosed with DME from 2012 to 2016, treated with intravitreal injection, and followed-up more than 24 months. Mean CMT in the ERM group was significantly thicker than in the non-ERM group after 9, 12, 18, and 24 months. Secondary ERM developed in 9.5% of patients during follow-up. Compared to other agents, the incidence of secondary ERM was significantly higher after intravitreal injection of dexamethasone implant. Among patients in the ERM group, the mean decrease of CMT between pre-injection and 2 weeks post-injection was significantly less after secondary ERM formation than before ERM formation. Secondary ERM formation was significantly associated with the number of intravitreal injections and the use of dexamethasone implant. Therefore, secondary ERM develops more frequently as the number of intravitreal injections increases and after intravitreal dexamethasone implant injection. The therapeutic effects of intravitreal injections for DME patients decrease after secondary ERM formation.
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http://dx.doi.org/10.1038/s41598-020-57509-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6969073PMC
January 2020

Angiographic features of drug-induced bilateral angle closure and transient myopia with Ciliochoroidal effusion.

BMC Ophthalmol 2019 Nov 4;19(1):213. Epub 2019 Nov 4.

Department of Ophthalmology, School of Medicine, Kyungpook National University, 130 Dongdeok-ro, Jung-gu, Daegu, 41944, South Korea.

Background: To report five cases of acute drug-induced angle closure and transient myopia with ciliochoroidal effusion and to analyze angiographic findings of these cases.

Methods: This study is an observational case series. Five patients with acute drug-induced angle closure and transient myopia with ciliochoroidal effusion were examined by fluorescein angiography, indocyanine green angiography (ICGA) and ultrasound biomicroscopy (UBM).

Results: Five patients presented with bilateral visual loss and ocular pain after intake of topiramate, methazolamide, phendimetrazine tartrate or mefenamic acid. All patients showed elevated intraocular pressure (IOP) with shallow anterior chamber and myopic shift from - 0.5 to - 17.0 diopters (D). UBM showed ciliochoroidal effusions with diffuse thickening of the ciliary body in all cases. Rapid normalization of IOP and decrease of myopic shift occurred in all patients after discontinuing the suspected drugs. We classified the ICGA findings into 2 major signs (hypofluorescent dark spots, hyperfluorescent pinpoints) and 3 minor signs (diffuse choroidal hyperfluorescence, early hyperfluorescence of choroidal stromal vessel, and leakage and dilated retinal vessels).

Conclusions: The pathogenesis of acute drug-induced angle closure and transient myopia with ciliochoroidal effusion may be idiosyncratic reaction of uveal tissue to systemic drugs. Accumulation of extravascular fluid in the ciliochoroidal layer had a major role in the pathogenesis. ICGA could be a useful method to examine the pathophysiology of this condition by imaging of the choroidal layer.
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http://dx.doi.org/10.1186/s12886-019-1230-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6829858PMC
November 2019

Weakly supervised lesion localization for age-related macular degeneration detection using optical coherence tomography images.

PLoS One 2019 5;14(4):e0215076. Epub 2019 Apr 5.

Department of Information and Communication Engineering, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu, Republic of Korea.

Age-related macular degeneration (AMD) is the main cause of irreversible blindness among the elderly and require early diagnosis to prevent vision loss, and careful treatment is essential. Optical coherence tomography (OCT), the most commonly used imaging method in the retinal area for the diagnosis of AMD, is usually interpreted by a clinician, and OCT can help diagnose disease on the basis of the relevant diagnostic criteria, but these judgments can be somewhat subjective. We propose an algorithm for the detection of AMD based on a weakly supervised convolutional neural network (CNN) model to support computer-aided diagnosis (CAD) system. Our main contributions are the following three things. (1) We propose a concise CNN model for OCT images, which outperforms the existing large CNN models using VGG16 and GoogLeNet architectures. (2) We propose an algorithm called Expressive Gradients (EG) that extends the existing Integrated Gradients (IG) algorithm so as to exploit not only the input-level attribution map, but also the high-level attribution maps. Due to enriched gradients, EG can highlight suspicious regions for diagnosis of AMD better than the guided-backpropagation method and IG. (3) Our method provides two visualization options: overlay and top-k bounding boxes, which would be useful for CAD. Through experimental evaluation using 10,100 clinical OCT images from AMD patients, we demonstrate that our EG algorithm outperforms the IG algorithm in terms of localization accuracy and also outperforms the existing object detection methods in terms of class accuracy.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0215076PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6450633PMC
January 2020

Post-radiation sarcoma: A study by the Eastern Asian Musculoskeletal Oncology Group.

PLoS One 2018 17;13(10):e0204927. Epub 2018 Oct 17.

Department of Orthopaedic Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seocho-gu, Seoul, Republic of Korea.

The oncologic risk of ionizing radiation is widely known. Sarcomas developing after radiotherapy have been reported, and they are a growing problem because rapid advancements in cancer management and screening have increased the number of long-term survivors. Although many patients have undergone radiation treatment in Asian countries, scarce reports on post-radiation sarcomas (PRSs) have been published. We investigated the feature and prognostic factors of PRSs in an Asian population. The Eastern Asian Musculoskeletal Oncology Group participated in this project. Cases obtained from 10 centers were retrospectively reviewed. Patients with genetic malignancy predisposition syndrome, or who had more than one type of malignancy before the development of secondary sarcoma were excluded. Forty-two high-grade sarcomas among a total of 43 PRSs were analyzed. There were 29 females and 13 males, with a median age of 58.5 years; 23 patients had bone tumors and 19 had soft tissue tumors. The most common primary lesion was breast cancer. The median latency period was 192 months. There were no differences in radiation dose, latency time, and survival rates between bone and soft tissue PRSs. The most common site and diagnosis were the pelvic area and osteosarcoma and malignant fibrous histiocytoma for bone and soft tissue PRSs. The median follow-up period was 25.5 months. Five-year metastasis-free and overall survival rates were 14.5% and 16.6%, and 39.1% and 49.6% for bone and soft tissue PRSs. Survival differences depending on initial metastasis and surgery were significant in soft tissue sarcomas. Although this study failed to find ethnic differences, it is the largest review on PRS in an Asian population. As early recognition through long-term surveillance is a key to optimal management, clinicians should take efforts to understand the real status of PRS.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0204927PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6192585PMC
March 2019

Origin of Satellite Ganglion Cysts with Effusion in the Flexor Hallucis Longus Tendon Sheath around the Hallux.

Clin Orthop Surg 2018 Mar 27;10(1):94-98. Epub 2018 Feb 27.

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

Background: To describe the clinical and magnetic resonance imaging findings of ganglion cysts with effusion in the flexor hallucis longus tendon sheath around the hallux to evaluate their origin.

Methods: Patients with recurrent or painful ganglion cysts around the hallux with effusion in the flexor hallucis longus tendon sheath who underwent surgical treatment at St. Vincent's Hospital from February 2007 to August 2016 were investigated. Surgical indication was a painful or recurrent mass caused by the cystic lesions. Those without effusion of the flexor hallucis longus tendon sheath were excluded. We assessed the clinical and magnetic resonance imaging findings.

Results: Magnetic resonance imaging findings in all patients showed several ganglion cysts around the hallux and large fluid accumulations within the flexor hallucis longus tendon sheath. Regarding the location, six ganglion cysts were on the dorsomedial aspect, one on the plantar medial aspect, seven on the plantar lateral aspect, and one in the toe pulp. Ten patients showed joint effusions in both the metatarsophalangeal and interphalangeal joints, two in the metatarsophalangeal joints, and three in the interphalangeal joints. There were communication stalks with a tail shape or abutment between ganglion cysts with surrounding joint effusions. Intraoperatively, connections between ganglion cysts, the synovial cyst of the flexor hallucis longus tendon sheath, and surrounding joints were seen.

Conclusions: Synovial fluid accumulation in the metatarsophalangeal or interphalangeal joint supplies the synovial cyst of the flexor hallucis longus tendon sheath and subsequently ganglion cysts in the hallux. In clinical practice, the surgeon should carefully check surrounding joints with tendon sheaths to prevent recurrence of the ganglion cysts around the hallux.
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http://dx.doi.org/10.4055/cios.2018.10.1.94DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5851861PMC
March 2018

Effect of a Fibroin Enzymatic Hydrolysate on Memory Improvement: A Placebo-Controlled, Double-Blind Study.

Nutrients 2018 Feb 17;10(2). Epub 2018 Feb 17.

School of Pharmacy and Health Professions, Creighton University Medical Center, Omaha 68178 NE, USA.

The consumption of a specifically prepared silk fibroin protein enzymatic hydrolysate (FPEH) has been reported to improve cognitive function in healthy humans. The objective of the current study is to evaluate the dose-dependent effects of the FPEH on memory. Healthy adults with an average age of approximately 55 years were administered doses of 0, 280, 400 and 600 mg of FPEH per day in two divided doses for 3 weeks. The Rey-Kim Auditory Verbal Learning Test and the Rey-Kim Complex Figure Test of the Rey-Kim Memory Test were used to evaluate memory at baseline and after 3 weeks. The scores for each test were combined into the memory quotient score (MQ). Learning gradient, memory maintenance, retrieval efficacy, and drawing/recall scores were also compared. After 3 weeks of FPEH, dose-dependent increases were observed for the MQ, the learning gradient, the numbers of words remembered, the retrieval efficiency, and drawing/recall. The optimal dose for FPEH was 400 or 600 mg, depending on the end point measured. No adverse effects were reported. FPEH significantly improved measurements of memory in healthy adults by 3 weeks at doses over 280 mg daily, with an apparent plateau effect at 400-600 mg daily.
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http://dx.doi.org/10.3390/nu10020233DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5852809PMC
February 2018

Short-term Analysis of the Residual Volume of an Eye Drop Following 23-Gauge Microincision Vitrectomy Surgery.

Korean J Ophthalmol 2017 Oct 6;31(5):439-445. Epub 2017 Jul 6.

Department of Ophthalmology, Kyungpook National University School of Medicine, Daegu, Korea.

Purpose: To evaluate the change of residual volume of eye drop after instillation in patients with 23-gauge microincision vitrectomy surgery (MIVS).

Methods: Patient who were treated 23-gauge MIVS from November 2014 to July 2015 were included. The residual volume was defined as the amount of remnant eye drop in patient's eyes after instillation, calculated as the difference between instillation volume and spilled volume of eye drop. Calculation of residual volume of eye drop was performed one day before surgery, and daily from postoperative day 1 to day 5.

Results: Forty consecutive patients were included. The residual volume of eye drop decreased from 30.3 ± 1.4 μL at baseline to 13.0 ± 1.5 μL at day 1, 18.3 ± 1.6 μL at day 2, 24.7 ± 1.5 μL at day 3, and 27.9 ± 1.4 μL in day 4, postoperatively (p < 0.001, respectively). The volume at postoperative day 5 was 29.4 ± 1.3 μL, but it was not different from the volume at baseline (p = 0.105). The change of residual volume was significantly correlated with postoperative chemosis (r = 0.672, p < 0.001) and effected by the number of quadrant with postoperative chemosis (p < 0.05).

Conclusions: This study shows that postoperative residual volume of eye drop after instillation decreased until postoperative day 4, and postoperative chemosis affects the change of residual volume. Thus, checking proper use of eye drops and teaching about instillation technique by physician is necessary for patients with 23-gauge MIVS.
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http://dx.doi.org/10.3341/kjo.2016.0090DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5636720PMC
October 2017

Thymic carcinoma initially presented with geographic destruction of scapula in a child.

Skeletal Radiol 2017 Oct 23;46(10):1421-1425. Epub 2017 Jun 23.

The Musculoskeletal Oncology Group, The Catholic University of Korea, Department of Orthopaedic Surgery, Uijongbu St. Mary's Hospital, The Catholic University of Korea, 65-1, Geumohdong, Gyunggido, 480-130, South Korea.

As the conventional histopathologic examination of thymic carcinoma (TC) is nonspecific, immunohistochemical studies along with correlative radiographic investigations are needed for its correct diagnosis. TC commonly occurs in the late 5th to early 6th decades of life but is extremely rare in childhood. It may be incidentally detected from chest radiographs taken as routine or for other reasons. However, most patients present with symptoms such as chest pain, cough, shortness of breath, dysphagia and hoarseness, which are directly attributable to the mediastinal mass. Although TC frequently invades the neighboring organs, pleura and pericardium and metastasizes to the lymph nodes, liver and lung at the time of the first diagnosis, initial or late metastasis to the bone has been seldom reported in adults. Indeed, the English literature revealed no earlier report on initial bony metastasis in a child to date. We report a case of TC in a 12-year-old boy who initially presented with scapular osteolysis masquerading as a primary bone tumor to emphasize the usefulness of combined imaging for staging and histologic studies, particularly for such an unexpected case.
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http://dx.doi.org/10.1007/s00256-017-2696-4DOI Listing
October 2017

Clinical Analysis of Ocular Parameters Contributing to Intraoperative Pain during Standard Phacoemulsification.

J Ophthalmol 2017 12;2017:9463871. Epub 2017 Apr 12.

Department of Ophthalmology, Kyungpook National University School of Medicine, Daegu, Republic of Korea.

. To study the correlation between ocular parameters and subjective pain that patients perceived during phacoemulsification. . Medical records of 142 patients who underwent standard phacoemulsification under topical anesthesia between March and August 2016 were retrospectively reviewed. The pain during phacoemulsification and 1 h after surgery was assessed and compared using a visual analog scale. In addition, demographic data, preoperative biometric parameters, and intraoperative surgical parameters were recorded. . Mean age of patients was 67.49 ± 12.50 years. The mean pain score was 2.26 ± 0.85 during phacoemulsification and 0.40 ± 0.69 postoperatively. Intraoperative pain was significantly associated with higher preoperative intraocular pressure ( = 0.220, = 0.016), greater anterior chamber depth ( = 0.210, = 0.028), and greater axial length ( = 0.181, = 0.043). . To reduce the subjective pain when patients have high preoperative intraocular pressure, large anterior chamber depth, or great axial length, supplementary procedures may be required.
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http://dx.doi.org/10.1155/2017/9463871DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5405601PMC
April 2017

Evaluation of the effects of the combination of autologous mesenchymal stem cells and platelet-rich plasma on structural bone allograft healing.

Cell Tissue Bank 2017 Jun 24;18(2):229-238. Epub 2017 Feb 24.

Research Institute of Medical Science, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.

In this study, we evaluated the efficacy of the combination of autologous mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP) for enhancing structural allogenic bone graft healing in rabbits. For these experiments segmental bone defects (1.5-2 cm) were generated on femoral diaphysis of New Zealand white rabbits and reconstructed via structural allogenic bone grafting and additional intramedullary nail fixation. The structural allografts were subsequently wrapped with Gelfoam containing autologous MSCs and PRP, or PRP alone (control). Grafted periosteal tissues were harvested at 4, 8, and 12 weeks post-implantation and subjected to plain radiographic and, histological, as well as real-time quantitative reverse transcription-PCR analysis of bone morphogenic protein (BMP)-2, BMP-4, BMP-7, receptor activator of nuclear factor-kappa B ligand (RANKL), and vascular endothelial growth factor (VEGF) expression. Compared to those in the control group, the animals in the experimental group exhibited significantly higher Taira radiographic scores at 4 and 12 weeks after surgery, as well as callus formation. Likewise, these animals exhibited increases in BMP-4 production at 4 weeks, RANKL production at 4 and 12 weeks, and BMP-2, BMP-7, and VEGF production at 4, 8, and 12 weeks. Together, these data suggest that the administration of autologous MSCs and PRP resulted in enhanced healing of structural allogenic bone grafts compared to PRP alone. As such, this combination might comprise an ideal therapy for improving the clinical outcomes of structural allografts.
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http://dx.doi.org/10.1007/s10561-017-9611-zDOI Listing
June 2017

Prognostic significance of chemotherapy-induced necrosis in osteosarcoma patients receiving pasteurized autografts.

PLoS One 2017 14;12(2):e0172155. Epub 2017 Feb 14.

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

Background: Among various reconstruction methods after wide excision for osteosarcoma, pasteurized autograft is often preferred. While the whole area of the tumor can be assessed for chemotherapy-induced necrosis, one of the important prognostic factors, in other reconstructive techniques, only a portion removed from a wide-resection specimen is available when using pasteurized autograft method. The assessment, therefore, may be unreliable. We analyzed the prognostic significance of the chemotherapy-induced necrosis in osteosarcoma patients who underwent reconstruction with pasteurized autografts.

Patients And Methods: We reviewed the records of osteosarcoma patients who underwent treatment in our institution from 1998 to 2013. Cases of reconstruction with pasteurized autografts were defined as the patient group, and the same number of patients who underwent other reconstruction methods served as controls. Chemotherapy-induced necrosis was evaluated for removed extra-osseous and curetted intramedullary tumor tissues.

Results: A total of 22 patients were identified; the median age was 15.5 years, and there were 12 males. The most common tumor location was the distal femur. The most common histological subtype was osteoblastic. Median size was 8.1 cm. Disease status was stage IIB in 13 patients and IIA in 9. Median follow-up was 76 months. No differences between the patient and control groups were observed in potential prognostic factors, overall survival, metastasis-free survival, or recurrence-free survival. Univariate analyses demonstrated that histological response was a significant prognostic factor for metastasis-free survival and also significant for recurrence-free survival.

Conclusion: Chemotherapy-induced necrosis grading, using only available tumor tissues, could be a prognostic factor for osteosarcoma patients receiving pasteurized autografts for reconstructive surgery.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0172155PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5308815PMC
August 2017

Retraction to: Memory-Enhancing Effects of Silk Fibroin-Derived Peptides in Scopolamine-Treated Mice.

J Microbiol Biotechnol 2016 12;26(12):2228

BrainOn Inc., Seoul 150-037, Republic of Korea.

This article has been retracted from JMB for misconduct of the authors (data fabrication and falsification). JMB as the publisher regrets for any inconvenience caused by the retraction.
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http://dx.doi.org/10.4014/jmb.2016.26.12.2228DOI Listing
December 2016

Sympathetic Ophthalmia after Ocular Wasp Sting.

Korean J Ophthalmol 2015 Dec 25;29(6):435-6. Epub 2015 Nov 25.

Department of Ophthalmology, Kyungpook National University School of Medicine, Daegu, Korea.

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http://dx.doi.org/10.3341/kjo.2015.29.6.435DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4668261PMC
December 2015

MicroRNA-31 functions as a tumor suppressor by regulating cell cycle and epithelial-mesenchymal transition regulatory proteins in liver cancer.

Oncotarget 2015 Apr;6(10):8089-102

Lab of Oncogenomics, Department of Pathology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.

MicroRNA-31 (miR-31) is among the most frequently altered microRNAs in human cancers and altered expression of miR-31 has been detected in a large variety of tumor types, but the functional role of miR-31 still hold both tumor suppressive and oncogenic roles in different tumor types. MiR-31 expression was down-regulated in a large cohort of hepatocellular carcinoma (HCC) patients, and low expression of miR-31 was significantly associated with poor prognosis of HCC patients. Ectopic expression of miR-31 mimics suppressed HCC cell growth by transcriptional deregulation of cell cycle proteins. Additional study evidenced miR-31 directly to suppress HDAC2 and CDK2 expression by inhibiting mRNA translation in HCC cells. We also found that ectopic expression of miR-31 mimics reduced metastatic potential of HCC cells by selectively regulating epithelial-mesenchymal transition (EMT) regulatory proteins such as N-cadherin, E-cadherin, vimentin and fibronectin. HCC tissues derived from chemical-induced rat liver cancer models validated that miR-31 expression is significantly down-regulated, and that those cell cycle- and EMT-regulatory proteins are deregulated in rat liver cancer. Overall, we suggest that miR-31 functions as a tumor suppressor by selectively regulating cell cycle and EMT regulatory proteins in human hepatocarcinogenesis providing a novel target for the molecular treatment of liver malignancies.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4480737PMC
http://dx.doi.org/10.18632/oncotarget.3512DOI Listing
April 2015

Osteosarcoma in Asian Populations Over the Age of 40 Years: A Multicenter Study.

Ann Surg Oncol 2015 Oct 13;22(11):3557-64. Epub 2015 Feb 13.

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

Background: Elderly patients with osteosarcoma (OSA) are no longer uncommon; however, many questions remain regarding this population. We investigated the clinicopathological characteristics and prognostic factors of OSA in an Asian population over the age of 40 years.

Methods: This was a multi-national, multi-institutional study by the Eastern Asian Musculoskeletal Oncology Group (EAMOG).

Results: A total of 232 patients were enrolled (116 males and 116 females), with a median age of 50 years at diagnosis; 25 (10.8 %) patients exhibited initial metastasis. Median follow-up was 52 months for survivors. We observed 102 osteolytic and mixed radiographic findings for 173 lesions. Histological subtypes other than osteoblastic type were frequent. Radiation-associated OSA was seen in seven patients, with a 5-year overall survival (OS) of 16.7 %. No Paget's OSA was observed. High-grade spinopelvic OSA was seen in 29 (12.5 %) patients. The 5-year OS was 59.4 % in patients without initial metastasis and 45.2 % in patients with spinopelvic OSA. While surgery and initial metastasis were common prognostic factors for OS, chemotherapy was not. Histologic response to neoadjuvant chemotherapy was poor in 61 of 83 patients.

Conclusion: This study revealed distinct clinicopathological features of OSA patients over 40 years of age compared with younger patients, such as the high incidence of axial tumors, common osteolytic and mixed radiographic findings, the high frequency of unusual histologic subtypes, and poor prognosis. Contrary to Western elderly patients with OSA, there was no Paget's OSA in this study, which may result in a lower incidence of secondary OSA. Prognostic factor analyses demonstrated chemotherapy did not influence OS.
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http://dx.doi.org/10.1245/s10434-015-4414-6DOI Listing
October 2015

Memory-enhancing effects of silk fibroin-derived peptides in scopolamine-treated mice.

J Microbiol Biotechnol 2013 Dec;23(12):1779-84

BrainOn Inc., Seoul 150-037, Republic of Korea.

Although enzyme-hydrolyzed silk fibroin has been reported to enhance cognitive function before, it has been still unknown which peptides can improve memory. Here we report that amino acid sequences of three novel peptides were identified from fibroin hydrolysate. Fibroin hydrolysate was obtained by hydrolysis with protease after partial hydrolysis with 5M CaCl2. Synthesized peptides derived from these sequences improved scopolamine-induced memory impairments in mice. We confirmed this hydrolysate had effects that improved learning and memory abilities by performing the Rey-Kim test. From this hydrolysate of silk fibroin, amino acid sequences of eight peptides were identified by LC-MS/MS. Three peptides (GAGAGTGSSGFGPY, GAGAGSGAGSGAGAGSGAGAGY, and SGAGSGAGAGSGAGAGSGA) were synthesized to investigate whether they could improve memory. Passive avoidance test and Morris water maze test were performed, and all peptides showed memory-enhancing abilities on scopolamine-induced memory impairments in mice. In this study, we identified three novel peptides that could improve memory, and that silk fibroin hydrolysate was a mixture of various active peptides that could enhance memory.
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http://dx.doi.org/10.4014/jmb.1308.08059DOI Listing
December 2013

Huge tophaceous pseudogout associated with tenosynovial chondromatosis arising from flexor digitorum tendon sheaths of the foot: a case report.

Skeletal Radiol 2013 Dec 5;42(12):1755-9. Epub 2013 Jul 5.

The Musculoskeletal Oncology Group, The Catholic University of Korea, Seoul, Korea,

Synovial chondromatosis (SC) is a benign proliferative process of synovial tissue creating multiple cartilaginous nodules in joints. It most commonly occurs in the large joints of the knee, hip, and shoulder, uncommonly in the small joints of the hand and foot, and only rarely in the tenosynovial membrane of tendon sheath, termed tenosynovial chondromatosis (TC). Unlike SC, TC predisposes to the foot or hand. The rarity and unfamiliarity of imagers with TC, as well as the variability of its histologic features often lead to an erroneous diagnosis of extraskeletal chondroma or even chondrosarcoma as in the present case. Calcium pyrophosphate dehydrate (CPPD) crystals are usually deposited in the articular cartilage or periarticular structures such as synovium and capsule, and rarely in other soft tissue structures including bursa, tendon, subcutaneous tissue, and dura mater. CPPD crystals may also be deposited in extraskeletal chondroma and SC. We present an exceptionally rare case of huge tophaceous pseudogout associated with TC that is considered to arise from the flexor digitorum longus tendon sheaths of the foot, initially mistaken for a chondrosarcoma.
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http://dx.doi.org/10.1007/s00256-013-1672-xDOI Listing
December 2013

(E)-N-(3,3-Diphenyl-allyl-idene)-4-nitro-aniline.

Acta Crystallogr Sect E Struct Rep Online 2012 Oct 29;68(Pt 10):o3031. Epub 2012 Sep 29.

Center for Neuro-Medicine, Korea Institute of Science & Technology, Hwarangro 14-gil, Seongbuk-gu, Seoul 136-791, Republic of Korea.

In the title compound, C(21)H(16)N(2)O(2), the dihedral angles between the mean planes of the 4-nitro-phenyl ring and the two phenyl rings are 57.3 (5) and 16.8 (6)°. The imine group displays a C-C-N-C torsion angle of -24.9 (3)°.
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http://dx.doi.org/10.1107/S1600536812040391DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3470385PMC
October 2012

(E)-N-(3,3-Diphenyl-allyl-idene)-3-nitro-aniline.

Acta Crystallogr Sect E Struct Rep Online 2012 Oct 29;68(Pt 10):o3030. Epub 2012 Sep 29.

Advanced Analysis Center, Korea Institute of Science & Technology, Hwarangro 14-gil, Seongbuk-gu, Seoul 136-791, Republic of Korea.

In the title compound, C(21)H(16)N(2)O(2), the 3-nitro-phenyl and two phenyl rings are twisted from the mean plane of the enimino fragment by 44.4 (1), 37.2 (1) and 74.1 (1)°, respectively. The crystal packing exhibits no classical inter-molecular contacts.
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http://dx.doi.org/10.1107/S1600536812040354DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3470384PMC
October 2012

Metastatic malignant tumour in the hand.

J Plast Surg Hand Surg 2011 Apr;45(2):90-5

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

Skeletal metastasis is a common event during the advanced stage of a malignant tumour, but metastasis to the hand is rare (about 0.1% incidence). We have seen seven cases of metastatic malignant tumour of the hand since 1983, and report them here.
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http://dx.doi.org/10.3109/2000656X.2011.556224DOI Listing
April 2011

The prognostic factors of recurrent GCT: a cooperative study by the Eastern Asian Musculoskeletal Oncology Group.

J Orthop Sci 2011 Mar 8;16(2):196-202. Epub 2011 Feb 8.

Department of Orthopedic Surgery, Graduate School of Medical Science, Kanazawa University, 13-1 Takara-machi, Kanazawa, 920-8641, Japan.

Background: Giant-cell tumor (GCT) of bone is a common primary benign tumor with high local recurrence and potential distant metastasis or malignant transformation. We have investigated the clinical behavior of recurrent GCT of bone in the extremities.

Methods: We retrospectively reviewed 110 patients with recurrent GCTs of bone in the extremities treated by the Eastern Asian Musculoskeletal Oncology Group. The factors that affected the number of recurrences and distant metastasis were analyzed.

Results: The median interval between initial surgery and the first recurrence of GCT was 16 months (2-180 months). All patients received additional surgery for first recurrence. Twenty-five patients had a second recurrence and 6 patients had a third recurrence. The mean interval between the initial surgery and the first recurrence correlated with the eventual number of recurrences-14.1 months for the repeated recurrence groups (two and three recurrences) and 28.3 months for the single recurrence group (p = 0.016). Campanacci grade did not correlate with repeated recurrence (p = 0. 446). The venue of the initial surgery did not correlate with recurrence but did affect preservation of the adjacent joint (chi-squared test; p = 0.046). Campanacci grade II and III also correlated with sacrifice of the adjacent joint (p = 0.020). The incidence of lung metastasis and malignant transformation were 7.5% (8 out of 107 patients) and 2.7% (3 out of 110 patients), respectively. Repeat recurrence was associated with lung metastasis (p = 0.018).

Conclusions: Early local recurrence of GCT is a risk factor for repeat recurrence. Repeat recurrence also correlates with lung metastasis. Recurettage with meticulous adjuvant treatment to completely preclude recurrent lesions is a reasonable method for preserving the adjacent joint. However, a continuous careful follow-up is mandatory.
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http://dx.doi.org/10.1007/s00776-011-0030-xDOI Listing
March 2011

Autologous mesenchymal stem cells loaded in Gelfoam(®) for structural bone allograft healing in rabbits.

Cell Tissue Bank 2011 Nov 21;12(4):299-309. Epub 2010 Jul 21.

Department of Orthopedic Surgery, St. Vincent's Hospital, The Catholic University of Korea, Ji-dong 93, Paldal-gu, Suwon, Gyeonggi-do, Korea.

This study was designed to evaluate the effect of autologous bone marrow mesenchymal stem cells (MSCs) seeded into Gelfoam® on structural bone allograft healing. Thirty New Zealand white rabbits were divided into two groups. Segmental bone defect was created on diaphysis of the femur, and the defect was reconstructed with structural bone allograft. In experimental group, structural allograft was wrapped around by Gelfoam® containing autologous MSCs, whereas cells were not included in control group. At 4, 8, 12 weeks, the femur of rabbits underwent radiographic and histologic evaluation for bony union. Bone morphogenic protein-2 (BMP-2), BMP-4, BMP-7, vascular endothelial growth factor (VEGF), and receptor activator of nuclear factor-kappa B ligand (RANKL) were measured within the grafted periosteal tissue. Bony union was not achieved in both groups at 4 and 8 weeks. At 12 weeks, three out of five femurs in experimental group were united, but one out of five in control group was united. Mean Taira scores were significantly different between two groups. The expression of BMP-2 was significantly higher at 4, 8 weeks, the expressions of BMP-4 and BMP-7 were significantly higher at 8 and 12 weeks, and the expression of VEGF and RANKL were significantly higher at all time points in experimental group. Incorporation of the structural bone allograft could be enhanced if allograft is covered with Gelfoam® containing autologous MSCs. MSCs have influence on not only bone formation, but neo-angiogenesis, and bone resorption.
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http://dx.doi.org/10.1007/s10561-010-9194-4DOI Listing
November 2011

Kimura's disease involving a long bone.

Skeletal Radiol 2010 May 28;39(5):495-500. Epub 2010 Jan 28.

Department of Orthopedic Surgery, The Catholic University of Korea, Seoul, Korea.

Kimura's disease is a rare, benign lymphoproliferative disorder of unknown etiology. It occurs most often in Asian men, usually in the second or third decade of life. Most lesions occur in the head and neck followed by the axilla, groin, popliteal region, and arm. The lesions are commonly found in soft tissues. To the best of our knowledge, there has been only one case report of bone involvement in Kimura's disease presented on plain radiography. We report a case of Kimura's disease that involved the proximal meta-diaphysis of the humerus and adjacent soft tissue shown on radiography and MR imaging.
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http://dx.doi.org/10.1007/s00256-009-0863-yDOI Listing
May 2010

Dysplasia epiphysealis hemimelica: radiographic and magnetic resonance imaging features and clinical outcome of complete and incomplete resection.

Skeletal Radiol 2010 Jan 8;39(1):85-90. Epub 2009 Oct 8.

The Musculoskeletal Oncology Group, The Catholic University of Korea, Uijungbu, Gyunggido, Korea.

Objectives: The objectives of this communication were to discuss radiographic and magnetic resonance (MR) imaging manifestations and clinical outcome after complete and incomplete resection of the mass of dysplasia epiphysealis hemimelica (DEH).

Materials And Methods: Clinical records, radiographs, and MR images of eight patients with DEH were retrospectively examined. Six patients were treated by complete excision of the lesional mass, and two patients were treated by incomplete resection at our University Hospitals during the period from 1980 to 2006.

Results: We found that, unlike in osteochondroma, DEH was radiographically not clearly separable from the underlying or host bone with preserved cortical bone and marrow continuity. The finding in the talus distinguished DEH from (osteochondroma-like) parosteal osteosarcoma, in which a radiolucent demarcation line clearly separated the tumor from the host bone. The DEH mass had a well-defined low to intermediate signal intensity on T1-weighted images and an intermediate to high signal intensity on T2-weighted images, with irregularity of the articular surface. Simple excision was performed in all patients. The excision was complete in six patients and incomplete in two patients whose lesions was juxta-articular in the ankle and articular in the knee, respectively. The residual mass slowly absorbed and vanished, resulting in mild flaring of the affected portion of the epiphysis. No local recurrence or complication was seen in any of the eight patients.

Conclusions: Although the radiographic signs of DEH are characteristic, (osteochondroma-like) parosteal osteosarcoma should be differentiated from DEH when there is a radiolucent separation line between the mass and host bone in the talus. Simple excision was effective in the management of DEH if the deformity was not complicated. Incompletely excised masses resolved and vanished with time.
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http://dx.doi.org/10.1007/s00256-009-0803-xDOI Listing
January 2010

The impact of the International Atomic Energy Agency (IAEA) program on radiation and tissue banking in Korea.

Cell Tissue Bank 2009 May 8;10(2):109-13. Epub 2008 Oct 8.

Department of Orthopedic Surgery, St. Vincent's Hospital, The Catholic University of Korea, Suwon, Republic of Korea.

In 1971, first bone bank was established at the Department of Orthopaedic Surgery in Catholic University of Korea. The first clinical case was reported at the Journal of Korean Orthopaedic Association in 1973. Subsequently, more than 60 surgical bone banks were established in the university and teaching hospitals throughout country. In 1990, the Korea Biomaterial Research Institute (KBRI) organised the IAEA/RCA training course on tissue banking. In this course students from 17 countries participated. In 1994 the first collaboration for cadaver tissue recovery was performed. It is important to single out that the various religious groups in Korea have favourable attitudes towards tissue donation, which contributes to the success of the tissue banking programs in the country. The demands of allograft were getting increased in the Korean medical and dental society. Currently, 62 hospital based bone banks, 5 processing tissue banks, 1 regional tissue bank and more than 30 tissue distributors are working in Korea. Based on the U.S.A. usage of more than 1,000,000 grafts per year, 100,000-200,000 grafts will be needed in Korea. Those findings indicate a greatly increased need for training of tissue bank operators. The Korean society will need at least 20-30 tissue bank operators for training in every year. The National Training Centre (NTC) for tissue bank operators and medical personal using the IAEA Curriculum in the Korean languages was established in 2003. From 2004 to 2006, NTC have been trained 40 tissue bank operators. They have produced at least 10,000 tissues per year. These figures indicate a cost saving of US$ 10 million. Within 5 years, NTC will train 100 tissue bank operators. These individuals and their respective banks will provide an increasing number of high quality grafts to the communities they serve at a cost far less than if they were acquired from abroad.
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http://dx.doi.org/10.1007/s10561-008-9083-2DOI Listing
May 2009
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