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Biomedical subjects

Young Min Park

Publications and source records attributed to Young Min Park.

At least 19 recordsLinked to original sources
PubMed2006

Effective removal of Ga residue from focused ion beam using a plasma cleaner.

Samples prepared using the focused ion beam (FIB) inevitably contain the surface damage induced by energetic Ga+ ions. An effective method of removing the surface damage is demonstrated using a plasma cleaner, a device which is widely used to minimize the surface contamination in scanning transmission electron microscopy (STEM). Surface bombardment with low-energy Ar+ ions was induced by biasing the sample immersed in the plasma source, so as to etch off the surface materials. The etch rates of SiO2, measured with a bias voltage of 100-300 V, were found to vary linearly with both the time and bias and were able to be controlled from 1.4 to 9 nm/min. The removal of the Ga residue was confirmed using energy dispersive spectroscopy (EDS) after the plasma processing of the FIB-prepared sample. When the FIB-prepared sample was processed via plasma etching for 10 min with a bias of 150 V, the surface Ga damage was completely removed.

Journal Article↗
PubMed2006

Localized intradermal microinjection of tranexamic acid for treatment of melasma in Asian patients: a preliminary clinical trial.

BACKGROUND: Melasma is a common cosmetic problem among Asians. While various treatments are currently being used, there is no entirely satisfactory treatment. It was recently reported that the topical plasmin inhibitor is an effective treatment for ultraviolet-induced hyperpigmentation. OBJECTIVE: Because there are no studies assessing the efficacy and safety of localized microinjection of tranexamic acid (TA) for the treatment of melasma, we conducted a pilot study to evaluate the efficacy and side effects of this potentially new method for the treatment of melasma in Korean women. METHODS: A total of 100 women with melasma, after written consent, were enrolled for a prospective open pilot study of 12 weeks. After applying topical anesthesia, 0.05 mL TA (4 mg/mL) was injected intradermally into the melasma lesion at 1 cm intervals by using a 0.5 mL insulin syringe with a 30-gauge needle. This was repeated weekly for 12 weeks. A clinical investigator evaluated the results by using the Melasma Area and Severity Index (MASI) at baseline and at 4, 8, and 12 weeks. The patient satisfaction questionnaire was documented at 12 weeks. Safety evaluations were performed at each follow-up visit. RESULTS: Eighty-five patients completed the trial. A significant decrease in the MASI from baseline to 8 and 12 weeks was observed (13.22+/-3.02 vs 9.02+/-2.62 at week 8 and vs. 7.57+/-2.54 at week 12; p<.05 for both). The patients' self-assessment of melasma improvement was as follows: 8 of 85 patients (9.4%) rated as good (51-75% lightening), 65 patients (76.5%) as fair (26-50% lightening), and 12 patients (14.1%) as poor (0-25% lightening). Side effects were minimal and all the patients tolerated the treatment well. CONCLUSION: Based on these results, we suggest that the intralesional localized microinjection of TA acid can be used as a potentially new, effective, and safe therapeutic modality for the treatment of melasma.

Adult↗
PubMed2006

Evaluation of natural change of skin function in split-thickness skin grafts by noninvasive bioengineering methods.

BACKGROUND: Autologous split-thickness skin grafts (STSGs) are considered the mainstay for the treatment of large full-thickness wounds. There have been few studies reporting the natural change of the skin function in STSGs after procedure, however. OBJECTIVE: The objective was to evaluate the natural change of the skin function in STSG using noninvasive bioengineering methods. METHODS: Eighteen patients were eligible for the study. The skin functions of the graft and the control site were evaluated by an evaporimeter, corneometer, mexameter, and cutometer at Postoperation Days 0.5, 1, 2, 3, 6, 9, and 12 months. RESULTS: Transepidermal water loss (TEWL) of the graft was maintained around that of the normal skin. The values of the skin hydration testing generally decreased during the follow-up period. Erythema was highly maintained for the whole period. For the pigmentation, the ratio tended to increase after 6 months. The skin pliability of the graft was abruptly decreased at 0.5 month, and it recovered from 3 to 12 months. The value did not reach that of the normal skin, however. CONCLUSION: Our results showed that the STSGs had changed within the frame of the skin function, including the TEWL, epidermal hydration, color, and pliability, throughout 1 year after surgery. The authors have indicated no significant interest with commercial supporters.

Adolescent↗
PubMed2005

Specific gene expression patterns in liver cirrhosis.

Liver cirrhosis (LC) is a complex disease that can develop into hepatocellular carcinoma (HCC). In an effort to investigate genetic differences between LC and HCC, we used cDNA microarray analysis to characterize the gene expression profiles in LC and HCC tissues. Consistent differences were observed among the expression patterns in LC, HCC, and normal liver tissues. Interestingly, the expression patterns of LC without tumor association (LCT) were also readily distinguished from those of LC tissues near hepatic tumor tissues (near-tumor tissue, NTT). Moreover, 25 cirrhosis-specific genes could be used to divide the NTT samples into two groups: inflammatory active cirrhosis (NTTa) and inflammatory inactive cirrhosis (NTTi). We found that NTTa samples showed gene expression patterns similar to those of the LCT and HCC groups, whereas the expression patterns of the NTTi group were significantly different from those of the LCT, NTTa, and HCC groups. Finally, we selected two of the 25 LC-specific genes and showed that these markers could be used to successfully discriminate among the different LC subtypes. Collectively, these novel results allow the identification of new genetic subgroups of LC and provide new candidate genes for use as early markers for active cirrhosis and HCC.

Biomarkers, Tumor↗
PubMed2005

Hepatitis B virus genotype C prevails among chronic carriers of the virus in Korea.

Hepatitis B virus (HBV) is one of the major causative agents of chronic liver diseases in Korea. HBV has been classified into 8 genotypes by a divergence of >8% in the entire genomic sequence, and have distinct geographic distributions. There are limited data on the relevance between HBV genotypes and clinical outcomes in Korea. To investigate the clinical feature relating to HBV genotype in Korea, a total 120 serum samples with HBsAg (65 from Seoul and 55 from the other city in Korea) were obtained from each 30 chronic HBV carriers with asymptomatic carrier (ASC), chronic hepatitis (CH), liver cirrhosis (LC) and hepatocellular carcinoma (HCC). HBV genotype was determined by either enzyme-linked immunosorbent assay (ELISA) using monoclonal antibodies against genotype-specific epitopes in the preS2-region or the direct sequencing of small S gene. HBV genotypes were determined in 105 (87.5%) of 120 samples. HBV genotype C was identified in all HBV carriers with ASC, CH, LC, and HCC. Genotypes A, B, D, E, F and G were not detected in any of them. Genotype C HBV prevails predominantly among chronic carriers of the virus in Korea, irrespective of their clinical stages of liver disease and geographic origin.

Carrier State↗
PubMed2005

Acrodermatitis enteropathica-like eruption associated with combined nutritional deficiency.

We present here a case of acrodermatitis enteropathica-like eruption associated with essential free fatty acid and protein deficiencies as well as borderline zinc deficiency that occurred after Whipple's operation in a 31-yr-old woman. Her eruptions were improved not by zinc supplements alone, but her condition was improved by total parenteral nutrition including amino acids, albumin, lipid and zinc. Although we could not exactly decide which of the nutrients contributed the most to her manifestations, we inferred that all three elements in concert caused her dermatoses. This case shows that even though the patient's skin manifestations and laboratory results are suggestive of acrodermatitis enteropathica, the physicians should keep in mind the possibility that this disease can be associated with other nutritional deficiencies such as free fatty acid or protein deficiency.

Acrodermatitis↗
PubMed2004

Therapeutic efficacy of multimodal combination therapy using transcatheter arterial infusion of epirubicin and cisplatin, systemic infusion of 5-fluorouracil, and additional percutaneous ethanol injection for unresectable hepatocellular carcinoma.

PURPOSE: Previous studies have shown that a treatment regimen using epirubicin, cisplatin, and 5-fluorouracil (5-FU) (ECF) has a survival benefit for gastric cancer patients. Based on these results and the hypothesis that a combination modality has a better therapeutic advantage over a single mode of therapy, the efficacy of multimodal combination therapy using a transarterial infusion of epirubicin and cisplatin, systemic infusion of 5-FU, and additional percutaneous ethanol injection (PEI) for unresectable hepatocellular carcinoma (HCC) was investigated in this study in comparison with conventional transarterial chemoembolization (TACE). PATIENTS AND METHODS: From July 1997 to September 1998, a total of 52 patients with unresectable HCC who underwent at least two cycles of transarterial chemotherapy were enrolled in this study. Among the 52 patients, 30 (ECF group) received a multimodal combination therapy comprising transarterial infusion of epirubicin (50 mg/m2) and cisplatin(60 mg/m2), systemic infusion of 5-FU (200 mg/m2), and additional PEI every 4 weeks, and the remaining 22(ADR group) received conventional TACE using Adriamycin (ADR, 50 mg) and Gelfoam every 8 weeks. RESULTS: During the follow-up period (mean 13.8 +/ -8.5 months), the objective tumor response of the ECF group was significantly higher than that of the ADR group (53.3 vs 22.7%, P=0.044). The median survival time was 13.5 months for the ECF group and 10.5 months for the ADR group (P=0.026). The cumulative survival rates at 6, 12, 18, and 24 months,respectively, were 90, 57, 27, and 17% for the ECF group and 73, 37, 7, and 0% for the ADR group. Uni-variate analysis showed five prognostic factors including tumor number, tumor morphology, portal vein thrombosis, Child-Pugh classification, and tumor response. With multivariate analysis, portal vein thrombosis and tumor response were identified as the two independent f actors for survival. No serious adverse effect was observed in the ECF group, while there was a higher tendency for hepatic complications in the ADR group. CONCLUSIONS: Combination therapy comprising transarterial infusion of epirubicin and cisplatin, systemic infusion of 5-FU, and additional PEI appears to be feasible and promising as a multimodal approach for unresectable HCC. Furthermore, it may provide a survival benefit for patients with more advanced disease.

Administration, Cutaneous↗
PubMed2004

Over-expression of c-raf-1 proto-oncogene in liver cirrhosis and hepatocellular carcinoma.

Liver cirrhosis accompanies at least 70% of hepatocellular carcinomas world-wide. To evaluate the dysregulation of apoptosis and the MAPK pathway in hepatocarcinogenesis, we investigated the expression profiles of the genes involved in apoptosis and MAPK pathway in cirrhosis and hepatocellular carcinoma. A total of 94 tissue specimens (61 cirrhosis and 33 hepatocellular carcinoma) obtained from 67 patients were analyzed by microarray, quantitative PCR and Western blot experiments. Of 71 apoptosis-associated genes, c-raf-1 and S6 were up-regulated in 42.9% and 32.1% of 28 cirrhosis tissues, respectively, and both genes were well correlated in a five-cluster K-means analysis. For c-raf-1 and down stream genes in the MAPK pathway, c-raf-1, MEK, and MAPK were up-regulated in 40%, 80%, and 86.7% of 45 cirrhosis specimens, respectively, and in 50%, 63.6%, and 59.1% of 22 hepatocellular carcinoma specimens, respectively. Western blot analysis showed that activated Raf-1 was over-expressed in 91.2% (52/57) of cirrhosis and in 100% (30/30) of hepatocellular carcinoma. The expression level of Raf-1 in 14 of 26 paired samples (53.8%) was significantly higher in hepatocellular carcinoma than in cirrhosis ( [Formula: see text] -fold, [Formula: see text] ). These results suggest that the activation of Raf-1 plays an important role in the development of hepatocellular carcinoma.

Journal Article↗
PubMed2004

Damage and recovery of skin barrier function after glycolic acid chemical peeling and crystal microdermabrasion.

BACKGROUND: Superficial chemical peeling and microdermabrasion have become increasingly popular methods for producing facial rejuvenation. However, there are few studies reporting the skin barrier function changes after these procedures. OBJECTIVE: To evaluate objectively the degree of damage visually and the time needed for the skin barrier function to recover after glycolic acid peeling and aluminum oxide crystal microdermabrasion using noninvasive bioengineering methods. METHODS: Superficial chemical peeling using 30%, 50%, and 70% glycolic acid and aluminum oxide crystal microdermabrasion were used on the volar forearm of 13 healthy women. The skin response was measured by a visual observation and using an evaporimeter, corneometer, and colorimeter before and after peeling at set time intervals. RESULTS: Both glycolic acid peeling and aluminum oxide crystal microdermabrasion induced significant damage to the skin barrier function immediately after the procedure, and the degree of damage was less severe after the aluminum oxide crystal microdermabrasion compared with glycolic acid peeling. The damaged skin barrier function had recovered within 24 hours after both procedures. The degree of erythema induction was less severe after the aluminum oxide crystal microdermabrasion compared with the glycolic acid peeling procedure. The degree of erythema induced after the glycolic acid peeling procedure was not proportional to the peeling solution concentration used. The erythema subsided within 1 day after the aluminum oxide crystal microdermabrasion procedure and within 4 days after the glycolic acid peeling procedure. CONCLUSION: These results suggest that the skin barrier function is damaged after the glycolic acid peeling and aluminum oxide crystal microdermabrasion procedure but recovers within 1 to 4 days. Therefore, repeating the superficial peeling procedure at 2-week intervals will allow sufficient time for the damaged skin to recover its barrier function.

Adult↗
PubMed2003

Purification and characterization of a cytosolic phospholipase A2 from rat liver.

A cytosolic phospholipase A2 (PLA2) was purified 640-fold from rat liver by sequential anion-exchange chromatography, Ca2+-precipitation/KCl-solubilization, gel filtration chromatography, and affinity chromatography. A single peak of PLA2 activity was eluted at an apparent molecular mass of 197 kDa from a Superdex 200HR gel filtration column. In the presence of Ca2+, the purified enzyme catalyzed the hydrolysis of 81.8 nmol of phosphatidylethanolamine per hour per mg of protein. The apparent Km was 1.83 nM. The enzyme was inhibited by arachidonyl trifluoromethyl ketone (AACOCF3), an inhibitor of cPLA2. However, it was not inhibited by bromoenol lactone (BEL), an inhibitor of iPLA2, and p-bromophenacyl bromide (p-BPB), an inhibitor of sPLA2. These data suggest that the purified enzyme is a novel Ca2+-dependent cytosolic PLA2.

Animals↗
PubMed2003

Comparison of proteome between hepatitis B virus- and hepatitis C virus-associated hepatocellular carcinoma.

PURPOSE: Hepatocellular carcinoma (HCC) is one of the most common malignant cancers closely associated with chronic infection by the hepatitis B virus (HBV) or the hepatitis C virus (HCV) throughout the world. Differential expression of the proteome in HBV- and HCV-associated HCC was investigated to identify any useful biomarkers indicating virus-specific hepatocarcinogenesis. EXPERIMENTAL DESIGN: Twenty-one pairs of specimens (tumorous and surrounding nontumorous liver tissues) were obtained from 21 HCC patients. They were divided into three HCC types by viral markers: 7 hepatitis B surface antigen-positive (B-type HCC), 7 anti-HCV-positive (C-type HCC), and 7 hepatitis B surface antigen-negative and anti-HCV-negative. Total proteins were analyzed by two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and alterations in the proteome were examined. RESULTS: Sixty proteins were identified that show significant changes in the expression level between nontumorous and tumorous tissues. Among these, 14 proteins were commonly changed in all three of the HCC types, but 46 proteins showed a tendency of viral marker specificity. CONCLUSIONS: The identified proteins were classified according to the viral factor as being involved in B-type and C-type HCC. These results suggest strongly that the expression pattern of proteome in HCC tissues is closely associated with etiologic factors. The different protein profiles between B-type and C-type HCC indicate that the pathogenetic mechanisms of hepatocarcinogenesis may be different according to the viral factor, HBV and HCV.

Carcinoma, Hepatocellular↗