Pancreatic Exocrine and Endocrine Cell Differentiation during Pancreatic Regeneration / 한양의대학술지

Pancreatic tissue is maintained by a simple proliferation of the preexisting cells in adulthood, whereas, they are dynamically derived from precursor/ stem cells from ductal epithelia during prenatal life. It has been known that tissue regeneration rarely occurs in the normal adult pancreas, particularly in the human pancreas. However, regeneration can be experimentally induced in the adult pancreas in response to various tissue injuries such as partial resection, pancreatitis by obstruction of the duct, and chemical insults. Regenerating pancreatic tissue shares a common morphogenic feature of "neogenic regeneration" in all regenerating animal models. Neogenic regeneration occurs at the site of tissue injury by forming small tubular structures with elongated epithelial cells (ductules) which grow to form pancreatic ducts and acini. The endocrine cells, including insulin secreting beta cells, are also derived from these ductules. As a sequential process of neogenesis, the regenerating tissue becomes heterogeneous in composition. Some areas were composed by tubules and ductules in surrounding loose connective tissue while others were denser with differentiating acini derived from tubules or ductules. Such neogenic regeneration mimics tissue development during fetal pancreatic organogenesis. In the process of pancreatic neogenesis, we found unique expressions of bioactive proteins such as nestin and clusterin as morphogenic factors. It is likely that the stem/precursor cells could be recapitulated and regenerated to functional cells, including endocrine and exocrine pancreatic cells with acinar and ductal cells during neogenic regeneration of the pancreas.

Superficial Cutaneous Mycoses in Korea / 한양의대학술지

Superficial cutaneous mycosis is mycotic infection of the epidermis of the skin, and one of common dermatoses in Korea. They have close relationship between host (human) and fungi. Their clinical patterns and incidence, and their causative fungi may change with social environments and life patterns. Since 1945, GNP has been increased explosively, more than 243 folds, and economic developments brought abrupt changes of social environments and life patterns in Korea. Furthermore, there had been great social events during this period; Korean War in 1950-1953, the Asian Game in 1986, the Olympic Game in 1988 and the World Cup in 2002. Those events gave much chances for dermatophytes to move and change. Tinea pedis is the most common dermatophytosis and has been increased from 26% of all dermatophytosis in late 1950s to 40.9-42.2%. And tinea unguium(onychomycosis) has been increased as tinea pedis does; Its proportion was 2.8% in late 1950s, and 17% in 1990s. The patients with tinea pedis have high family infection rate and also have high coexisting dermatophytosis. The most common isolate was Trichophyton(T.) rubrum, followed by T. mentagrophytes and Epidermophyton floccosum. Tinea capitis showed the most dramatic changes; its incidence was the highest just after Korean war and decreased abruptly since 1970s. Microsporum(M.) ferrugineum was the most common isolates till 1970s, and abruptly decreased and now nearly disappeared. Trichophyton(T.) violaceum was isolated in Cheju island. After Korean war, T. schoenleinii was isolated from favus and is disappeared. M. canis was isolated for the first time in 1959 and has been the most common isolates since late 1970s. T. verrucosum was isolated in 1986, and T. tonsurans was isolated for the first time in 1995 and spread among wrestlers, Judo players and Korean wrestlers. It might be imported by wrestlers with sport exchanging program. In cidence of tinea cruris was dramatically changed and was 5% of all dermatophytosis in 1940s, and 26.6-39.1% in 1990s. Those changes might be related to change of life patterns. Proportion of cutaneous candidiasis among superficial cutaneous mycosis was 1.9% in 1960s, 6.7% in 1973, 14.6% in 1976-1985, and 7.4% in 1989-1992. Proportion of pityriasis versicolor among superficial cutaneous mycosis was 12.1% in 1973, 7.7% in 1976-1985, and 7.7% in 1989-1992. Research for Malassezia have been increasing since late 1990s and that will bring us many new informations.

Changing Patterns of Dermatophytosis and Its Causative Agents according to Social and Economic Developments in Korea / 대한의진균학회지

Deramtophytosis is one of common dermatoses and occupied 10~20% of all dermatologic outpatients in Korea. It has close relationship between host (human) and dermatophytes. Their clinical patterns and incidence, and their causative dermatophytes may change with social environments and life patterns; Some dermatophytes may decrease or disappear and others can be imported from other countries. During recent 60 years, GNP has been increased explosively, more than 190 folds, and that economic developments brought abrupt changes of social environments and life patterns in Korea. Furthermore, there had been great social events; Korean War in 1950~1953, the Asian Game in 1986, the Olympic Game in 1988 and the World Cup in 2002. Those events gave much chances for dermatophytes to move and change. Trends of clinical types of dermatophytosis and their causative dermatophytes were evaluated with reported articles during the period. Tinea capitis showed the most dramatic changes. Its incidence was the highest just after Korean war, 24.5% of all primary school students, and decreased abruptly by 26.5% of all dermatophytosis in late 1950s, 4.9% in late 1960s, and 2~4% since 1970s. Microsporum(M.) ferrugineum was the most common isolates till 1970s, and abruptly decreased and now nearly disappeared. Trichophyton(T.) violaceum was isolated in Cheju island. After Korean war, T. schoenleinii was isolated from favus and disappeared. M. canis was isolated for the first time in 1959 and has been the most common isolates from tinea capitis since late 1970s. T. verrucosum was isolated for the first time in 1986 in Kwangju and has been isolated nation-widely. T. tonsurans was isolated for the first time in 1995 in Daegu and spread among wrestlers, Judo players and Korean wrestlers. It might be imported by wrestlers with sport exchanging program. Tinea pedis is the most common dermatophytosis in Korea now. It was 26% of all dermatophytosis in late 1950s, and increased by 40.9~42.2% in 1970s. And tinea unguium has been increased as tinea pedis does; It was 2.8% of all dermatophytosis in late 1950s, and increased by 5.1~14.2% in 1970s, 5.5~15.3% in 1870s and 17% in 1990s. The patiets with tinea pedis have high family infection and also high coexisting dermatophytosis. The most common isolate was T. rubrum, followed by T. mentagrophytes and Epidermophyton floccosum. Tinea cruris was one of dramatically changed dermatophytosis. Its incidence was 5% of all dermatophytosis in 1940s, and increased by 10.2% in late 1950s, and 26.6~39.1% in 1970s. Environments and socioeconomic conditions are changing, and international travel and sports exchanging program are increasing. All those social events may cause new dermatophytes to invade from other countries. We should check it carefully and continuously.