Biomedical subjects
Publications and source records attributed to Chil-Hwan Oh.
Fluorescence resonance energy transfer has been used to illustrate its applicability to the sensitive detection of DNA hybridization reactions in a PDMS microfluidic channel.
Raman spectroscopy has strong potential for providing noninvasive dermatological diagnosis of skin cancer. In this study, confocal Raman microscopy was applied to the dermatological diagnosis for one of the most common skin cancers, basal cell carcinoma (BCC). BCC tissues were obtained from 10 BCC patients using a routine biopsy and used for confocal Raman measurements. Autofluorescence signals from tissues, which interfere with the Raman signals, were greatly reduced using a confocal slit adjustment. Distinct Raman band differences between normal and BCC tissues for the amide I mode and the PO2- symmetric stretching mode showed that this technique has strong potential for use as a dermatological diagnostic tool without the need for statistical treatment of spectral data. It was also possible to precisely differentiate BCC tissue from surrounding noncancerous tissue using the confocal Raman depth profiling technique. We propose that confocal Raman microscopy provides a novel method for dermatological diagnosis since direct observations of spectral differences between normal and BCC tissues are possible.
BACKGROUND: In the evaluation of the severity of skin inflammations, visual scoring system is widely being used as a subjective method. However, it is well known that interobserver variations occur even between the interpretations of experienced dermatologists. OBJECTIVE: To develop a new objective and quantitative method for the evaluation of skin surface contours and for the assessment of severity in SLS-induced edema, a new investigatory tool based on the concept of "stereoimaging" was studied. Differences between binocular images were used by a stereoimage optical topometer (SOT) system capable of calculating skin surface topographic information, which was then used to produce a three-dimensional image. METHODS: We compared the results obtained by SOT with a visual scoring system after applying sodium lauryl sulfate (SLS) to skin. The degree of edema was assessed qualitatively by visual scoring (0: none, 1: mild edema, 2: moderate edema, 3: severe edema). To quantify the severity, five three-dimensional parameters (S(a), S(z), SL, SA and SV) were used in the SOT analysis. RESULTS: The means of these five parameters increased significantly in visual grade 1+ compared to visual grade 0 and the means of the five parameters decreased significantly and proportionally as the visual grades increased from 1+ to 3+. A highly significant correlation was found to exist between the visual scoring results and the five SOT parameters. CONCLUSION: SOT can be used to evaluate the severity of SLS-induced edema objectively and can be extensively applied to evaluate the degree of severity in other inflammatory skin conditions.
The severity of psoriasis has been traditionally assessed by measures, such as the psoriasis area and severity index (PASI), the psoriasis severity scores, and the lesional severity scores. As a result, even experienced dermatologists show variations when attempting to determine the severity of psoriasis. Therefore, a better non-invasive and objective measurement of clinical signs is needed. In this study, an instrument, a so-called 'stereoimage optical topometer' (SOT), based on a new concept of 'stereoimaging' was used to measure the three-dimensional skin surface. The aim of this study was to compare the results obtained by the SOT with the visual score of psoriasis lesion. Thirty psoriatic patients were enrolled in this study. Initially, the severity of the infiltration and the scale of 134 psoriatic lesions were assessed by using a visual scoring system (0: none, 1: mild, 2: moderate, 3: severe, and 4: very severe), as scored by five dermatologists. The SOT was then used to quantify the severity of each psoriatic lesion using four three-dimensional SOT parameters (Sa, SL, SA, and SV). Secondly, the involved skin-surface area in the psoriasis cases was scored by the naked eye by the five dermatologists and by image analysis. Statistically significant differences were observed between grades 0, 1, 2, and 3 in terms of the severity measurements of the individual psoriatic lesions by SOT when using the parameters Sa, SL, SA, and SV. Therefore, it was concluded that there is a strong correlation between the results measured by visual scoring and by SOT in psoriasis.
BACKGROUND: Occasionally, Bowen's disease and bowenoid papulosis cannot be distinguished in microscopic finding. Their clinical presentations are quite different from one another. The purpose of this study was to evaluate the histological differences in Bowen's disease and bowenoid papulosis, by comparing the size and shape of nuclei, using image analysis system. METHODS: We performed morphometric assessment on 13 specimens of Bowen's disease and eight specimens of bowenoid papulosis using an image analysis system, and the following parameters were calculated, such as nuclear contour index (NCI), irregularities of nucleus (IN), form factor (form AR) and circulatory factor (form PE). RESULTS: For NCI, there were significant differences between the Bowen's disease and bowenoid papulosis, and IN also shows significant differences between these two dis-eases, showing that Bowen's disease has more corrugated or indented nucleus contour than bowenoid papulosis. In the parameter of form PE, there were significant differences between the two diseases, indicating that Bowen's disease has more oval-shaped nuclei than bowenoid papulosis. There were no significant differences in form factor between Bowen's disease and bowenoid pupulosis. CONCLUSIONS: Significant differences were found in the morphometric evaluation between Bowen's disease and bowenoid papulosis. The nuclei were larger, more oval and more irregular margins in Bowen's disease than bowenoid papulosis.
BACKGROUND/AIMS: Although difficult, it is essential to assess the disease severity of psoriasis objectively. The visual grading method currently used for assessing the involved surface area in patients with psoriasis, which is included on the Psoriasis Area and Severity Index (PASI) scoring system, is a subjective method. The aim of this study was to establish the reliable objective method, in estimating the involved surface area in patients with psoriasis. METHODS: Thirty patients with psoriasis participated in this study. The skin lesions of each patient were estimated using the visual grading method and an image analysis system. RESULTS: The differences between five dermatologists' estimates of the involved surface area obtained from the visual grading method were highly significant (P<0.05, Kruskal-Wallis test). The comparison between the visual grading method and the image analysis system showed that the involved areas measured by the visual grading method were significantly higher than those from the image analysis (P<0.05, Wilcoxon signed rank test). CONCLUSIONS: The visual grading method was neither objective nor reproducible. On the other hand, the image analysis system can be used as an objective method of measuring the involved surface area of patients with psoriasis. Therefore, the image analysis system can be used as a standard for the assessment of the involved area of patients with psoriasis.