Biomedical subjects

Sang-Ho Lee

Publications and source records attributed to Sang-Ho Lee.

At least 19 recordsLinked to original sources

PubMed2007

Percutaneous endoscopic discectomy for extraforaminal lumbar disc herniations: extraforaminal targeted fragmentectomy technique using working channel endoscope.

STUDY DESIGN: A retrospective analysis of 41 patients operated for excision of soft lumbar extraforaminal disc herniation (EFDH) by percutaneous endoscopic extraforaminal approach under local anesthesia by a new technique. OBJECTIVES: To describe a new and safer percutaneous endoscopic technique for the removal of soft EFDH and report the results on the basis of a new objective criterion modified from Oswestry Disability Index (ODI). SUMMARY OF BACKGROUND DATA: EFDHs usually occur in older patients and present with atypical symptoms. Their diagnosis and treatment are still controversial, with various authors describing open midline or paraspinal approaches using the microscope with varying amounts of success. Percutaneous endoscopic techniques have traditionally been considered unsuitable for these herniations. METHODS: Forty-one patients with a soft EFDH were subjected to percutaneous endoscopic discectomy with the new technique. In our technique, the skin entry point is medial and the angle of approach steeper as compared with the earlier described endoscopic techniques. This might help in avoiding exiting root injury and increasing the efficacy of the procedure. The results were analyzed on the basis of percentage change in ODI as compared with preoperative values. RESULTS: Mean follow-up was 34.1 month. Mean VAS score for radicular pain improved from 8.6 to 1.9, and mean ODI improved from 66.3 to 11.5. Overall, 92% of patients experienced satisfactory outcome. Two patients had poor outcome due to the need for subsequent open surgery. CONCLUSION: Percutaneous endoscopic discectomy using the "extraforaminal targeted fragmentectomy" technique is an effective and safe procedure for the select group of patients with a soft EFDH.

Adult↗

PubMed2007

Modified transcorporeal anterior cervical microforaminotomy for cervical radiculopathy: a technical note and early results.

A prospective analysis of the first twenty patients operated for cervical radiculopathy by a new modification of transcorporeal anterior cervical foraminotomy technique. To evaluate early results of a functional disc surgery in which decompression for the cervical radiculopathy is done by drilling a hole in the upper vertebral body and most of the disc tissue is preserved. Earlier approaches to cervical disc surgery either advocated simple discectomy or discectomy with fusion, ultimately leading to loss of motion segment. Posterior foraminotomy does not address the more common anterior lesion. Twenty patients suffering from cervical radiculopathy not responding to conservative treatment were chosen for the new technique. Upper vertebral transcorporeal foraminotomy was performed with the modified technique in all the patients. All the patients experienced immediate/early relief of symptoms. No complications of vertebral artery injury, Horner's syndrome or recurrent laryngeal nerve palsy were noted. Modified transcorporeal anterior cervical microforaminotomy is an effective treatment for cervical radiculopathy. It avoids unnecessary violation of the disc space and much of the bony stabilizers of the cervical spine. Short-term results of this technique are quite encouraging. Longer-term analysis can help in outlining the true benefits of this technique.

Adult↗

PubMed2007

Antitumor activity of novel indirubin derivatives in rat tumor model.

PURPOSE: The novel indirubin derivatives 5'-nitro-indirubinoxime, 5'-fluoro-indirubinoxime, and 5'-trimethylacetamino-indirubinoxime were designed and tested for antitumor activity both in vitro and in vivo using rat tumor model. EXPERIMENTAL DESIGN: Three-week-old male Sprague-Dawley rats were inoculated s.c. on the left flank with 10(7) RK3E-ras rat kidney epithelial cells harboring k-ras gene. Alternatively, 5 x 10(6) RK3E-ras cells were injected into the oral mucosa. Indirubin derivative treatment began on the 3rd or 6th day after oral or s.c. cell injection, respectively. Indirubin derivatives were directly injected into the tumor every other day for a total of five times. Animals were monitored daily and tumor volume was measured by caliper. RESULTS: Indirubin derivatives showed potent antiproliferative activity on various human cancer cells and oncogenic RK3E-ras rat kidney cells, with IC(50) ranging from 1 to 12 mumol/L. Treatment with indirubin derivatives induced the activation of caspase-7 followed by apoptosis in RK3E-ras cells. Indirubin derivatives showed strong antitumor activity in rat solid and oral tumor models. Direct injection of indirubin derivatives every other day for 10 days induced significant inhibition of tumor growth in Sprague-Dawley rats bearing RK3E-ras-induced tumors. Histologically, treatment with indirubin derivatives caused significant inhibition of tumor formation with increased apoptosis and decreased tumor cell proliferation. CONCLUSIONS: Our data showed that novel indirubin derivatives 5'-nitro-indirubinoxime, 5'-fluoro-indirubinoxime, and 5'-trimethylacetamino-indirubinoxime effectively arrested the tumor growth by inhibiting cell proliferation and inducing apoptosis. These findings provide the potential value of indirubin derivatives as novel candidates for antitumor agents.

Animals↗

PubMed2006

Pure epidural cavernous hemangioma of the cervical spine that presented with an acute sensory deficit caused by hemorrhage.

Pure epidural cavernous hemangioma of the spine without vertebral involvement is rare. Due to the slow growth of this lesion, the most common symptoms are chronic pain, myelopathy, and radiculopathy. In our case, the patient complained of an acute onset sensory deficit of the C4 dermatome. An MRI revealed an epidural mass with an acute hematoma. Here, we report a case of a pure epidural cavernous hemangioma that presented with acute neurologic symptoms caused by intralesional hemorrhage and an acute epidural hematoma, which were demonstrated on the patient's MRI.

Cervical Vertebrae↗

PubMed2006

Detection and spectral analysis of trifluoromethyl groups at a surface by sum frequency generation vibrational spectroscopy.

Sum frequency generation (SFG) vibrational spectroscopy was used to detect the presence of trifluoromethyl groups on the surface of 4-(trifluoromethyl)benzyl alcohol (TFMBA) in air. Supplementary data from infrared and Raman spectra were correlated to ab initio calculations by use of density functional theory (DFT) for TFMBA and three related compounds to reliably assign vibrational modes to the spectra. It was shown that strongly ordered CF3 groups dominate the surface of the TFMBA, and the vibrational modes of this functional group are strongly coupled to the benzene ring of the benzyl alcohol. This coupling, along with the SFG activity of the CF3 group, is removed with the insertion of an oxygen atom between the CF3 group and the benzene ring.

Journal Article↗

PubMed2006

Percutaneous endoscopic lumbar discectomy for migrated disc herniation: classification of disc migration and surgical approaches.

Percutaneous endoscopic lumbar discectomy (PELD) for migrated disc herniations is technically demanding due to the absence of the technical guideline. The purposes of this study were to propose a radiologic classification of disc migration and surgical approaches of PELD according to the classification. A prospective study of 116 consecutive patients undergoing single-level PELD was conducted. According to preoperative MRI findings, disc migration was classified into four zones based on the direction and distance from the disc space: zone 1 (far up), zone 2 (near up), zone 3 (near down), zone 4 (far down). Two surgical approaches were used according to this classification. Near-migrated discs were treated with "half-and-half" technique, which involved positioning a beveled working sheath across the disc space to the epidural space. Far-migrated discs were treated with "epiduroscopic" technique, which involved introducing the endoscope into the epidural space completely. The mean follow-up period was 14.5 (range 9-20) months. According to the Macnab criteria, satisfactory results were as follows: 91.6% (98/107) in the down-migrated discs; 88.9% (8/9) in the up-migrated discs; 97.4% (76/78) in the near-migrated discs; and 78.9% (30/38) in the far-migrated discs. The mean VAS score decreased from 7.5 +/- 1.7 preoperatively to 2.6 +/- 1.8 at the final follow-up (P < 0.0001). There were no recurrence and no approach-related complications during the follow-up period. The proposed classification and approaches will provide appropriate surgical guideline of PELD for migrated disc herniation. Based on our results, open surgery should be considered for far-migrated disc herniations.

Adolescent↗

PubMed2006

Irreducible representation and projection operator application to understanding nonlinear optical phenomena: hyper-Raman, sum frequency generation, and four-wave mixing spectroscopy.

Symmetry plays an essential role in understanding optical activities of a molecule in infrared and Raman vibrational spectroscopy as well as in nonlinear optical vibrational spectroscopy. Each vibrational mode belongs to an irreducible representation of the underlying symmetry group. In this paper, using the alpha-helical polypeptide symmetry as an example, we calculate all the third rank nonzero hyper-Raman tensors as well as the infrared and Raman tensors by applying the projection operators to each irreducible species. We demonstrate that the projection operator method provides selection rules for the infrared, Raman, and hyper-Raman vibrational transitions and also other nonlinear optical spectroscopy such as sum frequency generation and the four-, five-, and six-wave mixing coherent vibrational transitions. Specific expressions for all nonzero elements of the corresponding nonlinear susceptibility tensors in a laboratory-fixed coordinate frame are also deduced.

Optics and Photonics↗

PubMed2006

A method of binding kinetics of a ligand to micropatterned proteins on a microfluidic chip.

A combination of microfluidic protein patterning and quantitative microfluidic handling has been used to analyze the binding kinetics of protein-ligand interactions on the nanoliter scale. The microfluidic handling method employing hydrophobic valving and pneumatic control allowed us to control nanoliter volumes of ligand or protein on a microfluidic chip. A hydrophobic and inert fluorocarbon thin film was patterned on a silicon nitride substrate to prevent non-specific binding on the background. Selectively patterned protein patterns of various sizes were used for quantitative analysis of the kinetic parameters of immobilized proteins on the circular patterns. As a model system, a streptavidin-patterned array of the same-sized pattern, i.e. 150 microm diameter, was used to capture FITC-BSA-biotin present in solution. The fluorescence intensity was well matched with the Langmuir isotherm model results, showing a dissociation constant of 2.43x10(-8)M. Similar streptavidin arrays with different-sized spots, ranging from 50 to 200 microm, showed a consistent dissociation constant of FITC-BSA-biotin with streptavidin pattern. Therefore, the reduction of pattern size of an immobilized protein did not change the dissociation rate of the ligand.

Biosensing Techniques↗

PubMed2006

Operative failure of percutaneous endoscopic lumbar discectomy: a radiologic analysis of 55 cases.

STUDY DESIGN: A retrospective study. OBJECTIVE: To determine the range of lumbar disc herniation that can be addressed effectively using current endoscopic techniques. SUMMARY OF BACKGROUND DATA: The current technical limitation of the procedure in terms of the location and size of the herniation has not been fully documented in previous studies. METHODS: The inclusion was an intracanal lower lumbar disc herniation in which subsequent surgery was performed because of the presence of remnant fragments. All 1586 cases, including 55 failed cases, were classified according to the size, location, and extent of migration. RESULTS: In the nonmigrated herniations, the central located high-canal compromised (>50%) herniations showed the highest rate of failure (15%), and the rate was significantly different from the low and high-canal compromise group (1.9% and 11.1%, respectively, P < 0.001). There was no significant difference in the failure rate between the nonmigrated herniations and low-grade migration group (2.7% and 3.7%, respectively). However, the high-grade migration group (beyond the measured height of the posterior marginal disc space) showed a significantly high-incidence of failure (15.7%, P < 0.001). CONCLUSIONS: Based on these results, open surgery may be considered for herniations with high-canal compromise and high-grade migration. On the other hand, percutaneous endoscopic lumbar discectomy can be considered to be a surgical option in the remaining intracanal disc herniations.

Adult↗

PubMed2006

Risk factor for unsatisfactory outcome after lumbar foraminal and far lateral microdecompression.

STUDY DESIGN: A retrospective study of consecutive patients who underwent microdecompression for far lateral disc or foraminal stenosis. OBJECTIVES: To evaluate the risk factors for unsatisfactory outcome. SUMMARY OF BACKGROUND DATA: There has been no detailed analysis of postoperative radicular pain, although it is not infrequent following foraminal and far lateral microdecompression. METHODS: A total of 184 patients, who were followed up for more than 2 years, were reviewed. Microdecompression was performed through lateral intermuscular approach. In cases of double herniation (combination of intracanalicular disc at the same level), additional intracanalicular decompression was simultaneously performed. The unsatisfactory outcomes included persistent or recurrent leg pain, based on the Japanese Orthopedic Association leg pain score, and revision surgery at the same level. The potential risk factors, including gender, age, symptom period, preoperative radiologic and intraoperative findings, were determined. RESULTS: The average follow-up period was 38.4 months, with a maximum 70 months. Forty of the 184 patients (21.7%) had persistent or recurrent leg pain, with nine requiring revision surgeries. The statistically significant risk factor for unfavorable outcomes was double herniation, with odds ratio of 2.89 (P = 0.004). CONCLUSION: Facet preserving microdecompression is an effective method for foraminal and far lateral root compression. However, in cases of double herniation, total facetectomy is preferable.

Adult↗

PubMed2006

Investigation of the beta-catenin gene in a case of dentinogenic ghost cell tumor.

Dentinogenic ghost cell tumor (DGCT) is considered as a neoplastic counterpart of the calcifying odontogenic cyst (COC). beta-catenin mutations have been described in COC suggesting a critical role in its histogenesis. In this study, we report a patient with DGCT contains a missense mutation on codon 3 (ACT --> TCT) of beta-catenin gene. Immunohistochemistry showed nuclear, cytoplasmic, and membranous accumulation of beta-catenin in the tumor cells. TUNEL assay showed positive signals in nucleated cells adjacent to the ghost cells. Our data suggest that beta-catenin plays an important role in the tumorigenesis of DGCT. DGCT may develop by an improper differentiation process coordinated by Wnt signaling pathway. Further studies are needed to determine the genotypic/phenotypic characteristics of ghost cell-containing odontogenic lesions.

Adult↗

PubMed2006

Rapid, sequence-specific detection of unpurified PCR amplicons via a reusable, electrochemical sensor.

We report an electrochemical method for the sequence-specific detection of unpurified amplification products of the gyrB gene of Salmonella typhimurium. Using an asymmetric PCR and the electrochemical E-DNA detection scheme, single-stranded amplicons were produced from as few as 90 gene copies and, without subsequent purification, rapidly identified. The detection is specific; the sensor does not respond when challenged with control oligonucleotides based on the gyrB genes of either Escherichia coli or various Shigella species. In contrast to existing sequence-specific optical- and capillary electrophoresis-based detection methods, the E-DNA sensor is fully electronic and requires neither cumbersome, expensive optics nor high voltage power supplies. Given these advantages, E-DNA sensors appear well suited for implementation in portable PCR microdevices directed at, for example, the rapid detection of pathogens.

Base Sequence↗

PubMed2006

Spinal intradural capillary hemangioma.

BACKGROUND: Capillary hemangiomas are typically superficial lesions found in the skin or mucosa of the head and neck, but intradural locations are rare. We report a case of the spinal intradural capillary hemangioma of the lumbar spine with a review of the pertinent literature. CASE DESCRIPTION: A 59-year-old man presented with a 3-month history of low back pain and left leg pain. On examinations, the patient was shown to have paresthesia in the left L4, L5, and S1 dermatome and a diminution of the left knee jerk. Magnetic resonance imaging revealed an approximately 2-cm intradural enhancing lesion at the level of the L1-2 disk space. Laminectomy of L1-2 was performed for tumor removal. A reddish mass was covered by matted adherent nerve roots and derived its blood supply from radicular vessels. Complete excision was accomplished. Histologic diagnosis was capillary hemangioma. After operation, the patient's symptoms were improved. CONCLUSION: We experienced a rare spinal intradural vascular tumor of the lumbar spine. Histologic diagnosis was capillary hemangioma. We report a rare case of spinal intradural capillary hemangioma of the lumbar spine.

Hemangioma, Capillary↗

PubMed2006

Microfluidic protein detection through genetically engineered bacterial cells.

Protein microarray technology, in which a large number of capture ligands are spatially arrayed at a high density, presents an attractive method for high-throughput proteomic analysis. Toward this end, we demonstrate the first cell-based protein detection in a microsystem, wherein Escherichia coli cells are genetically engineered to express the desired capture proteins on the membrane surface and are spatially arrayed as sensing elements in a microfluidic device. An E. coli clone expressing peptide ligands with high affinity and high specificity for target molecules was isolated a priori. Then these cells were electrokinetically immobilized on gold electrodes using dielectrophoresis, thus allowing each sensor element to be electrically addressable. Flow cytometry and subsequent fluorescence analysis verified the highly specific capture and detection of target molecules by the bacteria. Finally, through the coexpression of peptide-based capture ligands on the cell surface and fluorescent protein in the cytoplasm, we demonstrate an effective means of directly linking the fluorescence intensity to the density of capture ligands.

Escherichia coli↗

PubMed2006

Immediate pain improvement is a useful predictor of long-term favorable outcome after percutaneous laser disc decompression for cervical disc herniation.

OBJECTIVE: The purpose of this study was to evaluate the long-term clinical outcome of percutaneous laser disc decompression (PLDD) for cervical disc herniation and to identify factors affecting long-term favorable outcome. BACKGROUND DATA: PLDD using the Ho:YAG laser has been regarded as an effective alternative for soft disc herniation. However, little is known about long-term favorable outcome parameters. METHODS: We retrospectively reviewed the clinical and radiological data of 60 patients who underwent PLDD with laser-assisted spinal endoscopy (LASE) for contained cervical soft disc herniation from January 1998 to January 2000. The clinical outcome was measured using the Macnab criteria. Statistical analysis was performed using Fisher's exact test. Sex, age, operated level and location of disc herniation, amount of laser energy, and time for symptom improvement were selected as parameters. RESULTS: The mean follow-up period was 71.0 months (range, 59-83 months). The mean age was 45.7 years (range, 26-68 years), and the mean symptom duration was 13.0 months (range, 2-60 months). The Visual Analogue Scale (VAS) score was significantly improved from 7.9 preoperatively to 2.6 at the final follow-up (p < 0.001). At the final follow-up, 51 (85.0%) patients achieved a favorable outcome. Immediate (within 24 h) pain relief was achieved in 19 patients, and it was strongly related to long-term success (p = 0.006). CONCLUSION: The long-term clinical outcome of PLDD with LASE was fairly good, with a success rate of 85%. Immediate pain relief is a useful prognostic factor predicting favorable outcome following the procedure.

Adult↗

PubMed2006

Transforaminal percutaneous endoscopic discectomy in the treatment of foraminal and extraforaminal lumbar disc herniations.

The objective of this study is to evaluate the efficacy of the endoscopic technique, as applied to patients with foraminal and extraforaminal disc herniations, and to report the outcome and complications. A retrospective analysis was performed of 35 consecutive cases of foraminal and extraforaminal lumbar disc herniation managed by posterolateral endoscopic discectomy. Pain was measured by means of the Visual Analog Score. Patient satisfaction was evaluated by the Macnab outcome criteria. The median follow-up period was 18 months (range 10 to 35 months). The mean Visual Analog Score improved from 8.6 before the surgery to 3.2 after the surgery. Overall, excellent or good outcomes were obtained in 30 (85.7%) of the 35 patients at the last follow-up examination, with both these outcomes showing statistically significant improvement (P<0.01). There were no complications related to the surgery, nor was any spinal instability detected. Three patients (8.6%) experienced persistent radiculopathy and subsequently underwent open microdiscectomy at the same level. We concluded that transforaminal percutaneous endoscopic discectomy is safe and efficacious in the treatment of foraminal or extraforaminal disc herniations. However, proper patient selection is paramount to ensure a satisfactory outcome after decompression of foraminal and extraforaminal disc herniations.

Adult↗

PubMed2006

Early clinical and radiologic outcomes of cervical arthroplasty with Bryan Cervical Disc prosthesis.

Among 61 patients underwent disc replacement with the Bryan prosthesis, 47 patients were followed more than 3 months and their clinical and radiologic data were retrospectively analyzed to clarify very early clinical and radiologic outcomes and complications of disc arthroplasty with the Bryan Cervical Disc prosthesis during the learning period. Mean follow-up period was 6 months. Mean age was 45.6 years. Single-level procedure was done in 39 patients and 2-level in 8; a total of 55 levels replaced. Neck disability index improved from 59.8% to 22.9%. Visual analog pain score (VAS) of the neck improved from 8.4 to 1.6. VAS of shoulder/arm pain improved from 8.8 to 2.4. Mean patients' subjective improvement rate of symptoms was 71.1%. According to improvement in the neck disability index and VAS (over 50% improvement rate in each parameter), patients' subjective improvement rate (over 50%), and patients' satisfaction, the surgical success was achieved in 39 patients (83%). Eight patients (17%) showed failure. Mean segmental angle became more kyphotic after surgery from -0.7 degree of kyphosis (-11 to 7.7 degrees) to -1.3 degrees (-32 to 20.9 degrees) without statistical significance (P=0.55). Among 24 segments that showed preoperative kyphosis, 13 (54.2%) showed aggravated kyphosis, 7 (29.1%) showed decreased kyphosis and 4 (16.7%) recovered to lordosis. Among 31 segments that showed preoperative lordosis, 19 (61.3%) showed loss of lordosis and 12 (38.7%) showed increased lordosis. Mean range of motion increased significantly after surgery (6.7 to 8.5 degrees, P=0.04). Preoperative and postoperative segmental kyphosis was not related to clinical success. Cervical arthroplasty with the Bryan Cervical Disc prosthesis failed to restore segmental lordotic angle. A concern arises because it is well known that the fusion in kyphotic curvature causes more frequent problems on adjacent levels in anterior cervical discectomy and fusion. For the present, it seems preferable to exclude the patient who already has significant segmental kyphosis from disc arthroplasty with Bryan Cervical Disc prosthesis.

Adult↗

PubMed2006

Percutaneous endoscopic interlaminar discectomy for intracanalicular disc herniations at L5-S1 using a rigid working channel endoscope.

OBJECTIVE: Percutaneous endoscopic transforaminal discectomy is often used as a minimally invasive procedure for lumbar disc herniation. However, a transforaminal approach posts limitations at the L5-S1 level owing to anatomic constraints, such as a high iliac crest or small intervertebral foramen and especially for migrated large intracanalicular disc herniations. We discuss the procedure and clinical results of percutaneous endoscopic interlaminar discectomy using a rigid working channel endoscope at the L5-S1 level and the relevant surgical anatomy. METHODS: We performed percutaneous endoscopic discectomy through the interlaminar approach in 67 patients who satisfied our inclusion criteria during the period from March 2002 to November 2002. All procedures were performed under local anesthesia. Under fluoroscopic guidance, we performed discography using indigocarmine mixed with radio-opaque dye. The 6-mm working channel endoscope was then introduced into the epidural space. Herniated disc material was removed using forceps and laser under clear endoscopic visualization. We retrospectively evaluated the 65 cases with more than 1.5 years of follow-up. The patients were evaluated using the visual analogue scale (VAS) and the Oswestry Disability Index (ODI). RESULTS: VAS for leg pain (preoperative mean, 7.89; postoperative mean, 1.58) and ODI (preoperative mean, 57.43; postoperative mean, 11.52) showed statistically significant (P = 0.00) improvement in their values at the last follow-up examination compared with preoperative scores. Of the study group, 90.8% individuals showed favorable result. The mean hospital stay was 12 hours. The average time to return to work was 6.79 weeks. Complications included two cases of dural injury with cerebrospinal fluid leakage, nine cases of dysesthesia that were transient, and one case of recurrence. Two patients required conversion to open procedure at the initial operation. There was no evidence of infection in any patients. CONCLUSION: Percutaneous endoscopic interlaminar discectomy is a safe, effective, and minimally invasive procedure for the treatment of intracanalicular disc herniations at the L5-S1 level in properly selected cases, especially when the transforaminal approach is not possible because of anatomic constraints.

Adult↗