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Biomedical subjects

Sang Won Han

Publications and source records attributed to Sang Won Han.

At least 19 recordsLinked to original sources
PubMed2006

Urachal anomalies in children: a single center experience.

The objective of this study is to define optimal diagnosis and treatment strategies for patients with urachal anomalies in the pediatric age group. The medical records of 21 children who had undergone surgery for urachal anomalies at Severance Hospital, Yonsei University College of Medicine from January 1990 to April 2005 were reviewed. The subjects included 14 males and 7 females (M:F 2:1). The four types of urachal anomalies confirmed were a urachal cyst in 10 patients (47.6%), a patent urachus in 6 (28.6%), a urachal sinus in 4 (19.0%) and a urachal diverticulum in 1 (4.8%) patient. The most common presenting complaint was umbilical discharge (n = 10, 40.0%), followed by abdominal mass (n = 9, 36.0%). Urachal anomalies were diagnosed by ultrasonography in 18 patients, and 7 of them were additionally examined by computed tomography. The remaining patients were diagnosed solely by surgical exploration. Excision was performed in all patients and was supplemented by partial cystectomy in three. Umbilical discharge was the most common clinical manifestation in our patients, suggesting that ultrasonography should be performed in patients with umbilical discharge to differentiate urachal anomalies. We found the most common anomaly to be the urachal cyst, and all patients were successfully treated by surgical excision.

Child↗
PubMed2006

Improved time intervals by implementation of computerized physician order entry-based stroke team approach.

BACKGROUND: The need for rapid evaluation and treatment of acute stroke patients has been well documented. A computerized physician order entry (CPOE) system can improve communication and provide immediate access to information, which may be useful for an effective team approach program targeted to reduce in-hospital time delays. METHODS: To reduce the time from a patient's arrival at the emergency department to thrombolysis, a team approach program using CPOE was developed, and its efficacy was investigated by comparing time intervals from arrival to evaluation and intravenous tissue-type plasminogen activator (tPA) treatment before and after the implementation of the program. RESULTS: Among 379 consecutive patients who were screened as potential candidates for thrombolysis, 25 patients (6.6%) received tPA during a 1-year period after initiation of the program. Fourteen patients were treated with tPA in the previous year. After program implementation, time from arrival to computed tomography scan was reduced from 34 to 19 min (p = 0.01). Time to report of complete blood count was also shortened from 52 to 33 min (p < 0.01). Finally, time from arrival to tPA treatment was reduced by 23 min (from 79 to 56 min; p < 0.01). Onset-to-door time tended to be longer after the program implementation (from 41 to 60 min; p = 0.14). CONCLUSIONS: Implementation of the CPOE-based team approach program significantly reduced time from emergency department arrival to evaluations and treatment.

Acute Disease↗
PubMed2006

A new subtype classification of ischemic stroke based on treatment and etiologic mechanism.

A new subtype classification of ischemic stroke was developed to reflect recent therapeutic strategies as well as evolving concepts of stroke definitions and mechanisms. In 200 consecutive patients with acute ischemic stroke, the inter-rater reliability and proportion of subtypes of the new classification system were assessed and compared with those of the Trial of ORG 10172 in the Acute Stroke Treatment (TOAST) classification. The most frequent subtype of the new classification was atherothrombosis (n = 80, 40%), followed by stroke of undetermined etiology (n = 54, 27%), small artery disease (n = 33, 16.5%), cardioembolism (n = 26, 13%), and stroke of other determined etiology (n = 7, 3.5%). Three raters agreed to the stroke subtype diagnosis in 165 out of 200 cases and the overall kappa value was excellent (kappa = 0.82). The new classification system for brain infarction was easy to use and had high inter-rater reliability.

Adult↗
PubMed2006

Early recanalization after intravenous administration of recombinant tissue plasminogen activator as assessed by pre- and post-thrombolytic angiography in acute ischemic stroke patients.

BACKGROUND AND PURPOSE: Recanalization rates after the intravenous (IV) recombinant tissue plasminogen activator (rt-PA) treatment have been poorly studied in acute stroke. METHODS: CT angiography was performed before IV rt-PA in all patients and digital subtraction angiography was undertaken for intra-arterial thrombolysis in cases of no improvement after rt-PA infusion. RESULTS: Forty-five patients were treated with IV rt-PA. Initial CT angiography showed relevant arterial occlusions in 35 patients. Recanalization after rt-PA therapy was demonstrated by digital subtraction angiography in 7 of the 31 patients with the occlusion on initial CT angiography: 2/16 in the internal carotid or proximal middle cerebral artery, 3/11 in the distal middle cerebral artery and 2/4 in the basilar artery occlusion. CONCLUSIONS: The early recanalization rate after IV rt-PA use was very low in cases with large proximal arterial occlusions. CT angiography before IV rt-PA may be useful for the prediction of its efficacy.

Angiography, Digital Subtraction↗
PubMed2006

Carcinoembryonic antigen (CEA) mimicry by an anti-idiotypic scFv isolated from anti-Id 6.C4 hybridoma.

Since carcinoembryonic antigen (CEA) is expressed during embryonic life, it is not immunogenic in humans. The use of anti-idiotypic (Id) antibodies as a surrogate of antigen in the immunization has been considered a promising strategy for breaking tolerance to some tumor associated antigens. We have described an anti-Id monoclonal antibody (MAb), designated 6.C4, which is able to mimic CEA functionally. The anti-Id MAb 6.C4 was shown to elicit antibodies that recognized CEA in vitro and in vivo. In the present study, we sought to verify whether a single chain (scFv) antibody obtained, the scFv 6.C4, would retain the ability to mimic CEA. Two scFv containing the variable heavy and light chain domains of 6.C4 were constructed with a 15-amino acid linker: one with and another without signal peptide. DNA immunization of mice with both forms of scFv individually elicited antibodies able to recognize CEA.

Adenocarcinoma↗
PubMed2006

Predictive implications of recurrent transient ischemic attacks in large-artery atherosclerosis.

BACKGROUND: It is uncertain whether recurrent transient ischemic attacks (R-TIAs), when comparing with single TIAs (S-TIAs), have any distinct mechanisms. METHODS: All consecutive patients with TIAs, who had been admitted for a 2-year period, were divided into two groups: those who had R-TIAs and those who had S-TIAs. Registry data, medical records, and imaging findings were reviewed and compared between the two groups. RESULTS: There were 85 patients who had TIAs: 42 patients had R-TIAs, and 43 patients had S-TIAs. On univariate analysis, R-TIA patients had less cardiac embolic TIA sources, less weakness, less speech disturbances, shorter symptom duration, a longer time interval from onset to treatment, less abnormalities on diffusion-weighted magnetic resonance imaging, and more significant relevant arterial stenoses. After logistic regression analysis, independent factors associated with R-TIAs were symptom duration < 10 min (odds ratio OR 3.62; 95% confidence interval CI 1.37-9.57), > or = 50% stenosis of the clinically relevant artery (OR 7.08; 95% CI 1.29-38.71), and absence of cardiac embolic sources (OR 0.04; 95% CI 0.002-0.71). CONCLUSIONS: R-TIAs may have pathophysiological mechanisms distinct from those of S-TIAs and so may provide a clue for the etiologic diagnosis, in that patients with R-TIAs are more likely to have large-artery atherosclerosis.

Angiography, Digital Subtraction↗
PubMed2006

Left colonic antegrade continence enema: experience gained from 19 cases.

PURPOSE: As problems have developed with the right colonic antegrade continence enema procedure (Malone's procedure/Monti's retubularized ileocolostomy), left colonic antegrade continence enema (LACE) procedure, in which retubularized ileum or sigmoid colon is anastomosed into the sigmoid colon, has gained popularity. The aim of the study was to describe our experience with the LACE procedure. METHODS: We retrospectively reviewed 19 LACE procedures that were performed at the Yonsei University College of Medicine Hospital (Seoul, Korea) from March 2001 to March 2005. RESULTS: Male-to-female ratio was 11:8, with median age of 10 years (range, 3-34 years). Most common diagnosis was meningomyelocele (78.9%, 15/19). The median total follow-up period was 23 months (range, 3-37 months); median antegrade continence enema volume used was 600 mL (range, 250-1500 mL); and median transit time was 30 minutes (range, 15-60 minutes). Patients performed antegrade continence enema with an average of once every 2 days (range, 0.3-3 days). Social continence was achieved in 14 patients (73.7%). Regurgitation of fecal material through stoma was not reported at all in 17 patients (89.5%). CONCLUSIONS: We recommend LACE as the procedure of choice for children with congenital malformations or any other condition predisposing to fecal incontinence or constipation intractable to conventional treatment.

Adolescent↗
PubMed2006

Superimposition of nutcracker syndrome in a hematuric child with idiopathic hypercalciuria and urolithiasis.

We report a 5-year-old girl with idiopathic hypercalciuria who developed gross hematuria and left flank pain despite normalization of calciuria, a renal stone, and microscopic hematuria. She was found to have nutcracker syndrome by renal Doppler ultrasound, which revealed the significant differences of the peak blood flow velocities in the two portions of the left renal vein.

Calcium Metabolism Disorders↗
PubMed2006

Paradoxically accelerated fatal brain herniation following thrombolytic therapy in acute ischemic stroke.

INTRODUCTION: The use of plasminogen activators (PAs) in acute stroke patients has dual effects. PAs are beneficial by dissolving thrombi occluding an artery, but may be harmful by their proteolytic and excitotoxic actions. METHODS AND RESULTS: We report two patients with a fatal brain herniation who rapidly deteriorated despite the successful recanalization and the sustained arterial patency or blood flow. Imaging studies taken after the thrombolytic treatment suggested early occurrence of cellular damage and profound breakdown of the blood-brain barrier. CONCLUSION: Fatal brain edema occurred after persistent reperfusion by the thrombolytic therapy. Paradoxical thrombolytic-induced injury, which has been suggested in experimental studies, might play a role.

Aged↗
PubMed2005

Rescue localized intra-arterial thrombolysis for hyperacute MCA ischemic stroke patients after early non-responsive intravenous tissue plasminogen activator therapy.

The outcome of patients who show no early response to intravenous (i.v.) tissue plasminogen activator (tPA) therapy is poor. The objective of this study was to evaluate the feasibility of rescue localized intra-arterial thrombolysis (LIT) therapy for acute ischemic stroke patients after an early non-responsive i.v. tPA therapy. Patients with proximal MCA occlusions who were treated by LIT (n = 10) after failure of early response [no improvement or improvement of National Institute of Health Stroke Scale (NIHSS) scores of < or = 3] to i.v. tPA therapy (0.9 mg/kg-10% bolus and 90% i.v. infusion over 60 min) were selected. The recanalization rates, incidence of post-thrombolysis hemorrhage and clinical outcomes [baseline and discharge NIHSS scores, mortality, 3 months Barthel index (BI) and modified Rankin score (mRS)] were evaluated. Rescue LIT therapy was performed on ten MCA occlusion patients (male:female = 3:7, mean age 71 years). The mean time between the initiation of i.v. tPA therapy and the initiation of intra-arterial urokinase (i.a. UK) was 117+/-25.0 min [time to i.v. tPA 137+/-32 min; time to digital subtraction angiography (DSA) 221+/-42 min; time to i.a. UK 260+/-46 min]. The baseline NIHSS scores showed significant improvement at discharge (median from 18 to 6). Symptomatic hemorrhage and, consequent, mortality were noted in 2/10 (20%) patients. Three months good outcome was noted in 4/10 (40%, mRS 0-2) and 3/10 (30%, BI > or = 95). In conclusion, rescue LIT therapy can be considered as a treatment option for patients not showing early response to full dose i.v. tPA therapy. Larger scale studies for further validation of this protocol may be necessary.

Aged↗
PubMed2005

Free radicals as triggers of brain edema formation after stroke.

Brain edema is a leading cause of death after stroke. Cytotoxic edema, which is most severe in astrocytes, begins within a few minutes of adenosine triphosphate depletion and reflects the ultimate infarct size. Vasogenic edema is caused by uncontrolled fluid leakage from the blood to the brain parenchyma through a weakened blood-brain barrier (BBB) and contributes to an actual net volume increase of the brain, which often leads to death. Recent research on ischemia-induced injury mechanisms of the microvasculature has led to the disclosure of the mechanisms and cellular pathways leading to BBB breakdown. In addition, the introduction of magnetic resonance imaging to clinical practice has enabled the evaluation of edema severity in stroke patients and differentiation between cytotoxic and vasogenic edema. Free radicals exert their deleterious actions during both cytotoxic and vasogenic edema. They can contribute to BBB disruption directly and can also trigger molecular pathways related to the dysfunction of ion transporters in the cell membrane and those related to increased vascular permeability. The development of effective therapeutic strategies aimed at reducing brain edema based on targeting specific molecular pathways involved may reduce death and disability from stroke.

Blood-Brain Barrier↗
PubMed2005

Elastin content of the renal pelvis and ureter determines post-pyeloplasty recovery.

PURPOSE: We evaluated the collagen-to-smooth muscle tissue matrix ratio and percentage of elastin in the renal pelvis, ureteropelvic junction (UPJ) and ureter, and compared these findings with the degree of obstruction, patient age and post-pyeloplasty renal recovery. MATERIALS AND METHODS: We analyzed histological sections from 75 patients with UPJ obstruction. Nine patients were excluded owing to bilateral UPJ obstruction and an improper specimen. We divided the specimen obtained from pyeloplasty into 3 parts, namely the renal pelvis above the obstruction, the obstructed UPJ portion and the ureter below the obstruction. To examine the collagen and smooth muscle, sections were stained using Masson's trichrome, and elastic van Giesson stain was used for elastin, smooth muscle and collagen. Collagen, smooth muscle and elastin populations were identified, and the tissue matrix ratio and percentage of elastin were calculated by color image analysis. RESULTS: In patients with lower ratios of collagen-to-smooth muscle in the UPJ proper hydronephrosis was more improved postoperatively (p = 0.049). In patients with a lower percentage of elastin in the renal pelvis, UPJ and ureter hydronephrosis was more improved postoperatively (p <0.0001). CONCLUSIONS: Because the UPJ portion was resected during pyeloplasty, the renal pelvis and the ureter remaining after pyeloplasty are likely to be related to improved hydronephrosis. A higher percentage of elastin in the renal pelvis and ureter contributes to inelasticity and low compliance, and results in a slower recovery from hydronephrosis after pyeloplasty.

Adolescent↗
PubMed2005

Extracorporeal pelvic floor magnetic stimulation in children with voiding dysfunction.

OBJECTIVE: To determine the effect of extracorporeal pelvic floor magnetic stimulation in children with an overactive bladder, as although such stimulation is an effective treatment for voiding dysfunction such as urge incontinence (UI) and urgency-frequency syndrome, experience in children is scarce. PATIENTS AND METHODS: This prospective study included 42 children diagnosed with an overactive bladder, based on urodynamic or video-urodynamic study; a complete follow-up was available in 34. The children were grouped into those with UI only, not monosymptomatic nocturnal enuresis (nMNE), or MNE, according to their symptoms. Clinical variables were assessed by recording a voiding and nocturnal enuresis diary before and after magnetic stimulation, the latter being administered twice a week for 4 weeks using a size-adjusted magnetic chair (each session took 20 min). RESULTS: The UI only and nMNE group had a significant decrease in voiding frequency and frequency of UI (P < 0.05); the MNE group also had a significant decrease in voiding frequency (P < 0.05). There was a significant increase in functional bladder capacity in all groups (P < 0.05) but no significant decrease in the mean volume and frequency of NE in the nMNE and MNE groups (P > 0.05). CONCLUSIONS: Extracorporeal pelvic floor magnetic stimulation has an acute effect on voiding dysfunction such as urge syndrome in children. However, controlled studies with a sham-stimulation group and various durations of stimulation are necessary for its application as a primary treatment for voiding dysfunction in children.

Child↗
PubMed2004

Over expression of the selectable marker blasticidin S deaminase gene is toxic to human keratinocytes and murine BALB/MK cells.

BACKGROUND: The blasticidin S resistance gene (bsr) is a selectable marker used for gene transfer experiments. The bsr gene encodes for blasticidin S (BS) deaminase, which has a specific activity upon BS. Therefore, its expression is supposed to be harmless in cells. The work reported on herein consisted of experiments to verify a possible toxicity of bsr on mammalian cells, which include several cell lines and primary cultures. RESULTS: Murine keratinocyte BALB/MK and human primary keratinocyte cells transduced with the retroviral vector LBmSN, which has an improved expression system of bsr, namely bsrm, died in five days after the transduction. Meanwhile the control vector LBSN, which expresses bsr, did not provoke cell death. The lethal activity of bsrm was observed only in human keratinocytes and BALB/MK cells among the cell types tested here. Death appears to be mediated by a factor, which is secreted by the BALB/MK transduced cells. CONCLUSION: By our study we demonstrated that the expression of bsrm gene is toxic to human keratinocytes and BALB/MK cells. It is likely over expression of BS deaminase gene is responsible for the death.

Aminohydrolases↗
PubMed2004

The results of antegrade continence enema using a retubularized sigmoidostomy.

Left colonic antegrade continence enema (ACE) has been reported only as an alternative to right colonic ACE-the Malone appendicostomy and Monti retubularized ileostomy. This paper evaluated the advantages of left colonic ACE using a retubularized sigmoidostomy (RS) as an appropriate method for maintaining fecal continence and as a first-line surgical treatment for patients with fecal incontinence or intractable constipation. Ten patients underwent surgery between March 2002 and June 2003: seven with meningomyelocele, one with cloacal anomaly, one with anorectal malformation, and one with lipoma of the spine. An RS tube was fashioned and then implanted using a segment of the sigmoid colon and exteriorized through the umbilicus. An enema was done 10 days after surgery using only normal saline. The outcomes were assessed after adjusting to the appropriate enema regimen for the 10 cases. The mean duration of the enema was 23.0+/-8.4 min, with 250 ml (range 80-800) as the median volume of fluid used. The enema interval ranged from 1-3 days. No patient showed any abdominal discomfort or soiling episodes, with the exception of one who experienced daytime fecal staining, but this occurred less than once per month. The self-cosmesis for the umbilical stoma was satisfactory. The RS procedure provided excellent continence control, with a shortening of the enema duration, a lower fluid volume, and good cosmesis, and without any ACE-related abdominal pain. This procedure can be used as a first-choice surgical treatment for intractable constipation and fecal incontinence.

Abdominal Pain↗
PubMed2004

Vestibular imbalance associated with a lesion in the nucleus prepositus hypoglossi area.

BACKGROUND: The nucleus prepositus hypoglossi (NPH) is known to be a neural integrator of horizontal eye movements. Although the role of the human NPH is not well known, it may also function in postural balance, in view of its anatomic connections with the vestibular nuclei and vestibulocerebellum and of lesion studies in experimental animals. OBJECTIVE: To show that the human NPH contributes to vestibular function in addition to eye movement control. DESIGN: Case series. SETTING: University hospital. Patients Six patients with small and discrete brainstem infarctions that predominantly involved the NPH region.Main Outcome Measure Findings on magnetic resonance images. RESULTS: The NPH was affected at the lower pontine level in 2 patients and at the upper medullary level in 4. In addition to gaze-evoked nystagmus, all patients had vertigo, vomiting, and postural ataxia, suggesting vestibular dysfunction. The patients typically fell contralaterally or bilaterally to the lesion side. CONCLUSION: The NPH serves a vestibular function in addition to its oculomotor control function.

Aged↗
PubMed2004

Chondrogenic differentiation of human mesenchymal stem cells using a thermosensitive poly(N-isopropylacrylamide) and water-soluble chitosan copolymer.

Poly(N-isopropylacrylamide) (PNIPAAm) is known to be thermally responsive material and has a lower critical solution temperature (LCST, 32 degrees C) at which a macromolecular transition from a hydrophilic to a hydrophobic structure occurs. Chitosan is a useful natural polymeric biomaterial due to its biocompatibility and biodegradable properties. It has good characteristics for cell attachment, proliferation and viability. The aim of this study was to assess the ability to differentiate from mesenchymal stem cells (MSCs) to chondrocytes and mass formation using a newly developed injectable material, a thermosensitive (water-soluble chitosan-g-PNIPAAm) gel, and evaluate cartilage formation in vivo after injecting a cell-thermosensitive gel complex. The MSCs were cultured in the chitosan-PNIPAAm in vitro. Fluorescence-activated cell sort analysis, viability test, collagen type I, II, X formation and the aggrecan levels were examined. These cultured cells can be easily recovered from a copolymer gel by simply lowering the temperature. An animal study was performed to assess cartilage formation in the submucosal layer of the bladder of rabbits. The cartilage formation could be detected. This can be used to treat vesicoureteral reflux or reflux esophagitis by the effective mass effect. This is a simple method (sol-gel technique in LCST), and good cartilage formation occurs in the bladder tissue.

Absorbable Implants↗