Biomedical subjects

Joong Sun Lee

Publications and source records attributed to Joong Sun Lee.

6 recordsLinked to original sources

PubMed2007

PPAR-gamma agonist, ciglitazone, increases pigmentation and migration of human melanocytes.

Peroxisome proliferator-activated receptors (PPARs) play an important role in cellular responses. It was reported that three subtypes of PPAR are expressed in human melanocytes. In this study, we investigated the effects of the PPAR-gamma agonist, ciglitazone, on pigmentation and migration of human melanocytes. Ciglitazone stimulated the melanin content of cells and cultured skin. This increase in pigmentation was due to the stimulation of tyrosinase activity and expression of tyrosinase and microphthalmia-associated transcription factor protein of the melanocytes. Migration was increased after ciglitazone treatment, which was observed by the Boyden chamber checkerboard analysis and a scratch motility assay. These results suggest the regulatory role of PPAR-gamma in pigmentation and migration of human melanocytes.

Cell Movement↗

PubMed2006

Peroxisome proliferator-activated receptors-gamma activator, ciglitazone, inhibits human melanocyte growth through induction of apoptosis.

Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear hormone receptor superfamily. All three PPAR subtypes, PPAR-alpha, PPAR-beta/delta and PPAR-gamma are expressed in human melanocytes. In this study, we investigated the effects of PPAR-gamma activator on melanocyte growth, and apoptosis. The PPAR-gamma activators ciglitazone, troglitazone, and 15-deoxy-prostaglandin J2 inhibited melanocyte growth in a dose-dependent manner. This inhibitory effect of ciglitazone seemed to occur through induction of apoptosis. Apoptosis was increased after ciglitazone treatment, which was observed by the TUNEL method and flow cytometry. We noted a decrease in extracellular signal regulated kinase protein expression under ciglitazone treatment. Western blot analysis revealed an apparent time-dependent reduction in Bcl-2 protein levels in ciglitazone-treated melanocytes. In terms of Bax expression, a difference was not found. The expression of caspase-3 proteins was increased time-dependently with ciglitazone treatment. These results indicate that melanocyte growth and apoptosis may be modulated through PPAR-gamma and that ciglitazone, a PPAR-gamma activator, inhibits growth of human melanocytes by inducing apoptosis.

Apoptosis↗

PubMed2006

Cutaneous ciliated cyst of the inguinal area in a man.

Cutaneous ciliated cysts are rare, predominantly occurring on the lower extremities of young women. Most of them have been regarded as müllerian remnants. Cases in men are rarely reported. We report a case of a cutaneous ciliated cyst involving the inguinal area of a 56-year-old man and briefly review the published work.

Biopsy, Needle↗

PubMed2005

Sclerosing segmental neurofibromatosis.

Segmental neurofibromatosis is a rare disorder characterized by cafe-au-lait macules and/or neurofibromas limited to a single body segment. The neurofibromas in segmental neurofibromatosis are usually soft, non-tender nodules as in other types of neurofibromatosis. Histopathologically, they are usually non-encapsulated, loosely textured dermal tumors. We report a case of sclerosing segmental neurofibromatosis, in which the patient presented with several grouped, erythematous to brownish, firm tender nodules on the left side of the posterior neck. Histopathologically, the stroma was mostly very fibrotic, especially around hair follicles, in addition to the usual features of neurofibroma. The atypical clinical feature, hardness, and tenderness of the lesions may be associated with the fibrosis.

Diagnosis, Differential↗

PubMedDate not supplied

The ultrastructural characteristics of the hair bulb of segmented heterochromia in the scalp hair.

Segmented heterochromia is a pigmentary disorder characterized by alternating dark and light segments on each hair shaft. Our aim was to observe the ultrastructure of hair shafts and bulbs to understand the pathogenesis of the disease. Biopsy specimens including normal or diseased hair follicles were prepared for transmission electron microscopy. In dark segments, dense and ellipsoidal melanosomes were noted while small, round ones were found in the light segments. Two groups of melanosomes lined up on the matrix, one of which was composed of compact ellipsoidal melanosomes, and the other was composed of melanosomes with irregular sizes and shapes. Melanocytes seemed to be under necrosis, apoptosis, or dark cell transformation. Langerhans cells were found in the bulb. Two kinds of melanosomes were produced in the same hair bulb simultaneously. Degenerating melanocytes might produce deformed melanosomes. Langerhans cells might be involved in the death of melanocytes. It is unknown how either group of melanosomes is adopted and transferred to the hair cortex producing the characteristic pattern of pigmentation.

Adolescent↗

PubMedDate not supplied

The nevoid pili multigemini over the back.

Pili multigemini is a rare developmental defect of hair follicles. It usually involves the beard of an adult and the scalp in children, but there have been no reported cases on the back. We report 3 cases of extensive pili multigemini over the entire back of healthy males. All cases were found incidentally. The direct microscopic examination of one hair follicle showed that it consisted of more than twenty shafts, which had rough surfaces and brush-like bulbs. The histological examination revealed that complicated follicular structures formed as many as 23 to even 36 hair shafts. Lots of hairs were surrounded by each inner root sheath and had one common outer root sheath. We suggest this nevoid is pili multigemini over the back.

Adult↗