Biomedical subjects
Publications and source records attributed to Kyoung Chan Park.
Eruptive lentiginosis is a rare condition characterized by the abrupt spreading of asymptomatic pigmented macules over the entire body without systemic associations. We report mother and daughter, both of whom developed abrupt dissemination of numerous pigmented skin lesions.
BACKGROUND/PURPOSE: Vitiligo and nevus depigmentosus (ND) present similar hypopigmented macules with significantly different prognoses. Although the distinction between the two diseases is important, differential diagnosis relies on medical history and physical examination, which is far from decisive in some cases. The Mexameter is an objective skin color-measuring device, and has been reported to provide a reproducible and sensitive means of quantifying small skin color differences. In this study, we investigated the usefulness of a Mexameter for discriminating these diseases. METHODS: A selection of 202 hypopigmented skin lesions (182 from vitiligo and 20 from ND) were the objects of this study. Using a Mexameter, MIs were obtained from lesions and symmetrically located control skin. RMIs, ratios of the MIs of lesional skins to control skins, were calculated. RESULTS: The mean MIs and RMIs were significantly different for vitiligo and ND. The mean RMI of ND lesions was 74+/-13, which was significantly higher than that of vitiligo lesions (50+/-24). No ND lesion had an RMI of <50%. CONCLUSION: This study shows that the Mexameter, an objective pigment-measuring device, can be used to achieve a more accurate diagnosis of hypopigmentary disorders, and that the relative melanin index (RMI), which represents the relative pigment levels, might be a more effective parameter than the melanin index (MI) itself for comparing pigmentation differences.
Heat shock proteins (HSPs) are known to protect cells from oxidative stress and other types of injuries. We previously reported the neuroprotective effect of HSP70 following cerebral ischemia and reperfusion using hsp 70.1 knockout (KO) mice. However, the precise role of HSP70 in neuroprotection has not been established yet. The purpose of this study was to investigate the relationship between HSP70 and antioxidant enzymes using hsp 70.1 KO mice. The activities of both SOD-1 and SOD-2 were significantly decreased in hsp 70.1 KO mice than in the wild type (WT) littermates. SOD-1 protein level in the hsp 70.1 KO mice was lower than that of WT. We speculate that HSP70 might be involved in regulation of expression of SOD-1 at the level of transcription or by post-transcriptional modification.
BACKGROUND/AIMS: Facial sebum secretions are known to change under various circumstances. Facial skin types have been categorized as oily, normal, dry, and combination types. However, these have been evaluated subjectively by individuals to date, and no objective accepted standard measurement method exists. The combination skin type is most common, but its definition is vaguer than the definitions of the other skin types. METHODS: We measured facial sebum secretions with Sebumeter. Sebum secretions were measured at five sites of the face seasonally for a year, in the same volunteers. Using the data obtained we developed a set of rules to define the combination skin type. RESULTS: Regional differences in sebum secretion were confirmed. Sebum secretions on forehead, nose, and chin were higher than on both cheeks. Summer was found to be the highest sebum-secreting season, and seasonal variations were found in the T- and U-zones. A mismatch of skin type in the T- and U-zones in more than two seasons appears to be close to subjective ratings of what is described as the 'combination' skin type. CONCLUSION: We showed that the face shows definitive regional and seasonal variations in sebum secretion. To define the combination skin type, seasonal variations in sebum secretion should be considered in addition to regional variations.
BACKGROUND: It is known that cellular senescence could affect culture results. A previous study on K19 found that the loss of stem cell proportion is the reason for difficulties experienced when culturing aged keratinocytes. But the situation is unclear, because K19 is not generally accepted as an epidermal stem cell marker. OBJECTIVE: The aim of this study was to investigate the effects of cellular senescence caused by chronological aging or by repeated subcultures. METHODS: The effects of cellular senescence were investigated using monolayer cultures of keratinocytes and reconstructed epidermis. We prepared keratinocytes from donors of different ages and by repeated subcultures. Flow cytometric analysis was performed using alpha6 integrin and CD71 antibodies, and candidate keratinocyte stem cell proportions were separated according to reactivities to these antibodies. Living skin equivalents (LSEs) were reconstructed using keratinocytes from child, adult and elderly donors. RESULTS: Flow cytometric analysis showed a decrease in the candidate stem cell proportion in an age- or culture passage-dependent manner. LSE experiments showed that a reconstructed epidermis using child's keratinocytes was well formed compared to epidermis reconstructed using an elderly donor's keratinocytes. Different expression of proliferation markers was also observed according to donor age. CONCLUSION: Our results showed that cellular senescence by chronological aging or repeated sub-culture induced the loss of candidate stem cell proportion in keratinocyte cultures. This seems to be the reason why it is difficult to culture keratinocytes from the elderly or by repeatedly culturing keratinocytes in vitro.
A subepidermal calcified nodule (SCN) is an uncommon form of calcinosis cutis that is not associated with other dermatologic or systemic illnesses. Clinically, SCN presents as a solitary, firm tumor that can be white, white-yellow, or erythematous. Most SCNs occur in children; they are extremely rare in adults. The treatment of choice is believed to be surgical excision. We describe a case of SCN on the right ear lobe of a 33-year-old male, which was treated using a CO2 laser and electrodessication.
BACKGROUND: There is increasing evidence that neuropeptides, especially substance P (SP), may be involved in the pathogenesis of atopic dermatitis (AD). OBJECTIVE: We performed this study to determine more precisely the role of SP in AD. METHODS: We separated peripheral blood mononuclear cells (PBMCs) from AD patients and normal controls, and measured proliferation response and cytokine release after adding SP (10(-11), 10(-10) and 10(-9) M). We also compared substance P receptor expression by semi-quantitative RT-PCR. RESULTS: PBMCs from AD patients proliferated at significantly higher rates (ca. by 30%). Semi-quantitative RT-PCR showed that the level of expression of SP receptor increased in AD patients versus normal controls. IL-4 release from PBMCs was significantly higher in AD patients, while IFN-gamma release from PBMCs was significantly lower in AD patients. Different concentrations of SP did not cause any difference in IL-4 and IFN-gamma secretions. However, TNF-alpha release from PBMCs in AD patients increased significantly at 10(-10) and 10(-9) M of SP compared to SP (-) control. IL-10 release from PBMCs increased significantly in AD patients with 10(-9) M of SP compared to SP (-) control. CONCLUSION: SP might aggravate AD by increasing the production of TNF-alpha and IL-10 rather than by affecting IL-4 and IFN-gamma. This different immune response is considered to be the result of upregulated SP receptor in AD.
Carcinoid tumors show variety of pathological features and some of them are admixed with adenocarcinoma. The carcinoma-carcinoid spectrum is a concept of classifying tumors based on the tumor mass differentiation which is composed of tissues of both endocrine and nonendocrine functions. When two types of tissues exist within one tumor intermingled with each other in a similar proportion, it is called composite tumor. On the other hand, collision tumor is characterized by the presence of two localized tissue types adjacently together. Gastric composite tumors are relatively rare. According to the reports on the Korean literature, there are several collision tumors, but only one case of gastric composite tumor has been cited. Reports of multiple synchronous or metachronous cancers have increased steadily during the last decades. Multiple gastric carcinoids or carcinoid tumors developed in association with gastric adenocarcinoma contribute to this trend. We report one case of gastric composite tumor simultaneously occurring with a early gastric adenocarcinoma with review of the literature.
There are diverse ring-like narrowings in the lower esophagus: mucosal ring, muscular ring, ring-like annular peptic stricture. Esophageal muscular ring is extremely rare and generally asymptomatic. It occurs at the proximal border of the esophageal vestibule that corresponds to the upper end of the lower esophageal sphincter. We experienced a case of lower esophageal muscular ring with a symptom of intermittent mild dysphagia for 40 years and report the findings with a review of the literature.
UV light is absorbed in the epidermis and induces sunburn cell formation. It has been reported that HSP70 increases the UVB resistance of cell lines by in vitro experiments using various cell lines. In this study, hsp70.1(-/-) KO mouse was used in order to study the role of HSP70 after UVB irradiation. Western blotting showed a decreased level of HSP70 in hsp70.1(-/-) KO mouse compared with wild type FVB mouse. Six h after UVB irradiation, there were no significant histologic differences between the hsp70.1(-/-) KO mouse and the wild type FVB mouse. A similar degree of nuclear swelling was observed. However, there were significant differences at 12 and 24 h after UVB irradiation. After 12 h, a few apoptotic cells were observed in the wild type mouse, but a large number of cells were apoptotic in the hsp70.1(-/-) KO mouse. After 24 h, the epidermis of the wild type FVB mouse was relatively intact, but almost the entire epidermis was necrotic in the hsp70.1(-/-) KO mouse. These results showed that epidermal injury of hsp70.1(-/-) KO mouse was much more severe than that of wild type mouse although initial changes are similar in both species of mice. These results suggest that susceptibility of hsp70.1(-/-) KO mouse to UVB irradiation may originate from a defect in the repair mechanism. This HSP deficient model may be useful in studies of the effects of tissue injury that relate to the impaired tissue repair mechanisms.
Ceramide is implicated in the regulation of various signaling pathways leading to proliferation, differentiation or apoptotic cell death, but there have been few investigations about the effects of ceramide on the cell growth and the melanogenesis of melanocytes. In the present study, we investigated the effects of cell-permeable ceramide on Malme-3M human melanoma cell line. MTT proliferation assay showed that C2-ceramide inhibited the growth of Malme-3M cells in a dose-dependent manner. Cell cycle analysis confirmed the inhibition of DNA synthesis by a reduction in the S phase and an increase in the G0/G1 phase. Flow cytometric analysis for apoptotic cells and morphological observations indicated that the antiproliferative effect of C2-ceramide was not due to apoptosis. We next investigated the effects of C2-ceramide on the pigmentation of Malme-3M melanoma cells. The results showed that C2-ceramide induced only a slight decrease of tyrosinase activity and melanin synthesis. To investigate the ceramide signaling pathway, we studied the influence of C2-ceramide on extracellular signal-regulated kinase (ERK) and Akt activation by Western blot. We demonstrated that the amount of phosphorylated Akt was decreased by C2-ceramide, whereas ERK was activated transiently. Because of a well-known involvement of ceramide in apoptosis, we further investigated the level of caspase-3 and HSP70 after treatment of C2-ceramide. We found that the caspase-3 was not activated and the expression of HSP70 increased moderately. In conclusion, C2-ceramide inhibited the cell growth of Malme-3M cells without the induction of apoptosis. We suggest that increased HSP70 may be related to the resistance against apoptosis.
Skin equivalent model provides a new investigating system to study the role of extracellular matrix and dermal factors such as collagen, basement membrane components and fibroblasts (Fb) which contribute to cell-cell and cell-matrix interactions. Although basement membrane factors is known to play an important role in epidermal differentiation and epidermal-matrix adhesion, comparative effects of these extracellular matrix and dermal factors on the reconstruction of epidermis are little known. In this study, we investigated effects of type I collagen (Coll I), type IV collagen plus laminin (LAM) coated Coll I (Coll IV+LAM), and human Fb enriched Coll I (Coll I+Fb) on epidermal reconstruction. When human keratinocytes were cultured on three different gels containing Coll I, Coll IV+LAM and Coll I+Fb, basal keratinocytes were cuboidal and perpendicular to the dermo-epidermal junction only in the gel containing Coll I+Fb. Proliferation marker expression was prominent and differentiation marker expression was similar with those of normal skin in the gel containing Coll I+Fb than in the other gel models. Since ascorbate is suspected to exert an effect as a modulator of proliferation and differentiation in keratinocytes, we tested the effects of ascorbate on human epidermis reconstruction. When 25 microg/ml ascorbate was added, disordered arrangement of epidermis was disappeared and differentiation marker expression was similar with its expression in normal skin. These data indicate that human Fb and a modulator of proliferation and differentiation such as ascorbate are essential for epidermalization in reconstructed epidermis.
BACKGROUND/AIMS: Facial skin is usually classified as dry, normal, and oily in the cosmetics field. However, there is no standard objective method for classifying facial skin. METHODS: We measured sebum excretion with Sebumeter at four sites on the face. Based on the amount of sebum secretion, we reclassified skin type according to the guidelines provided by the manufacturer. The mean of sebum excretion (mean facial sebum excretion; MFSE) was also calculated. RESULTS: People secrete varying amounts of sebum at different skin sites. Reclassification of skin type based on sebum secretion revealed that most participants underestimated the amount of facial sebum excretion. When sebum secretion amounts were compared, a statistically significant difference was apparent between the oily and dry skin types. However, there were no statistical differences between oily and normal, and normal and dry skin. CONCLUSION: We showed that subjective skin type does not match the amount of sebum secreted. Thus, this simple and subjective classification is of very limited use and it should be re-evaluated by using an objective and standardized measuring tool.
1. Fructose-1,6-diphosphate (FDP), a glycolytic metabolite, is reported to ameliorate inflammation and inhibit the nitric oxide production in murine macrophages stimulated with endotoxin. It is also reported that FDP has cytoprotective effects against hypoxia or ischaemia/reperfusion injury in brain and heart. However, underlying mechanisms of its various biological activities are not completely understood. 2. In this study, we examined the effects of FDP on UVB-induced prostaglandin production in HaCaT keratinocytes. 3. Ultraviolet B (UVB, 280-320 nm) irradiation (30 mJ cm(-2)) increased prostaglandin E(2)(PGE(2)) production, which was significantly decreased by FDP in a concentration dependent manner. NS-398, a cyclo-oxygenase-2 (COX-2) selective inhibitor completely inhibited UVB-induced PGE(2) production showing that COX-2 activity is responsible for the increase in PGE(2) production under our experimental conditions. 4. UVB irradiation increased total COX activity and COX-2 mRNA in HaCaT keratinocytes, which were significantly blocked by FDP in a concentration dependent manner. 5. N-acetylcysteine (NAC) significantly attenuated UVB-induced PGE(2) production, COX activity and COX-2 mRNA expression indicating oxidative components might contribute to these events. 6. FDP reduced UVB-induced increase in cellular reactive oxygen species (ROS) level although it did not show direct radical scavenging effect in the experiment using 1,1-diphenyl-2picrylhydrazil (DPPH). FDP preserved the cellular antioxidant capacity including catalase activity and GSH content after irradiation. 7. Our data obtained hitherto suggest that FDP may have a protective role in UVB-injured keratinocyte by attenuating PGE(2) production and COX-2 expression, which are possibly through blocking intracellular ROS accumulation.