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Biomedical subjects

S Im

Publications and source records attributed to S Im.

12 recordsLinked to original sources
PubMed1992

Epidermal changes in active vitiligo.

Light and electron-microscopic studies were performed on the vitiligo and adjacent, normal appearing skin from 97 patients with actively spreading vitiligo and 19 patients with stable vitiligo. The vitiliginous skin revealed complete loss of pigment and melanocytes. In addition to degenerative changes in melanocytes, vacuolar changes of basal cells, epidermal infiltration of lymphocytes, dermal infiltration of lymphocytes, and melanophages in the upper dermis were also seen in the normal appearing skin adjacent to vitiliginous skin. These epidermal and dermal changes are more prominent in the skin of actively spreading vitiligo than in stable vitiligo. These findings suggest that the adjacent, normal appearing skin of actively spreading vitiligo shows some characteristic histopathologic findings, especially in the epidermis, indicating that cellular immunity could be involved in the pathogenesis of vitiligo.

Acute Disease↗
PubMed1992

Culture of melanocytes obtained from normal and vitiligo subjects.

The development of human melanocyte culture in vitro from normal adult skin and uninvolved skin of vitiligo patients is essential to investigate the mechanism of depigmentation in vitiligo and other pigmentary dermatoses. By using selective growth and long-term maintenance conditions, we selectively cultured melanocytes derived from normal foreskins and arm skins, and uninvolved foreskins and arm skins of vitiligo patients. The melanocytes of the arm skins were successfully cultured from the roofs of suction blisters. Melanocyte Growth Media (MGM) consisting of MCDB-153 formulation with basic fibroblast growth factor (bFGF), bovine pituitary extract (BPE), insulin, hydrocortisone, phorbol 12-myristate 13-acetate (PMA) and 10% human AB serum was sufficient to grow the melanocytes from normal and vitiligo donors. Melanocytes from uninvolved skin of vitiligo donors showed no different morphologic features, initial seeding capacity and population doubling time compared with those from normal skin. Melanocytes from both cell types grew without any lag period for more than 6 months (6-11 passages). Melanocytes obtained from foreskins had higher initial seeding capacity and shorter population doubling time than those obtained from arm skins using suction-blistered roofs. Our results suggest that the culture method using suction blisters may be a simple and easy way to obtain melanocytes. In addition, vitiligo melanocytes can be successfully cultured with appropriate growth conditions and may show no defective growth patterns. This culture system will be applied to investigate the basic pathophysiology of vitiligo and other various pigmentary dermatoses.

Cells, Cultured↗
PubMed1991

Hydroa vacciniforme with unusually severe scar formation: diagnosis by repetitive UVA phototesting.

Hydroa vacciniforme is a rare, chronic, photosensitive disorder manifested in childhood by recurrent vesicles that heal with scarring. Reproduction of vesicles with repetitive UVA phototesting may be an important diagnostic aid. Recurrent eruption resulted in severe scarring of the face and a flexion contracture of the finger in our patient. The clinical features and laboratory evaluation of hydroa vacciniforme are reviewed.

Adolescent↗
PubMed1991

Treatment of vitiligo with oral 5-methoxypsoralen.

Thirty-six patients with vitiligo were treated with oral 5-methoxypsoralen (5-MOP) and subsequently exposed to UVA irradiation. The patients were treated once or twice weekly over a period of 2-10 months, taking 40-60 mg of 5-MOP 2 hours before exposure to UVA light. The amount of exposure to UVA light was slowly increased according to the patient's tolerance. Eleven (31%) patients showed remarkable repigmentation of the areas of vitiligo within six months. Overall, 78% of the patients showed effective repigmentation. Areas of vitiligo on the face and trunk were more responsive to treatment than those on the distal part of limbs. Adverse effects due to the drug included 2 patients with nausea and 1 patient with headache. It is suggested that treatment with systemic 5-MOP is effective, safe, and useful in selected cases of vitiligo.

Administration, Oral↗
PubMed1991

The ultraviolet B protection effects of topically applied melanosomes onto human skin.

Melanosome is a cellular organelle that is composed of a melanosomal matrix and a brown biochrome, melanin which is formed by tyrosine-tyrosinase reactions. The melanosome is formed within the melanocyte and transferred to the surrounding keratinocytes through dendritic processes. Human skin color is related to the number, size, type and distribution of melanosomes, and the major role of melanosomes is to prevent skin from injurious nonionizing ultraviolet radiation. Controlled NaOH hydrolysis and centrifugation of human hair make it possible to isolate large amounts of melanosomes which are synthesized within the follicular melanocytes and transferred to hair matrix cells. In this study, the sun protection factors of topically applied melanosomes isolated from human hair were evaluated using ultraviolet B phototesting. Topically applied melanosomes increased the minimal erythemal doses. And the sun protection factors of each 50% and 25% melanosomal preparation were 12.3 +/- 5.5 and 3.1 +/- 1.3 respectively, and these ultraviolet B protection effects showed statistically significant differences from 10%, 5% and 1% melanosomal preparations and vehicle. Form these results, the dose-related photoprotective role of melanosomes was confirmed.

Humans↗
PubMed1990

An epidermoid cyst with a seborrheic verruca-like cyst wall.

The epidermoid cyst with a seborrheic verruca-like cyst wall is a newly described variant of the epidermoid cyst. The cyst wall of this variant shows changes simulating seborrheic keratosis and verruca. Our case of a subcutaneous mass was shown histopathologically to have this variant.

Adult↗
PubMed1989

Likelihood estimation of quantitative genetic parameters when selection occurs: models and problems.

Conceptual aspects of estimation of genetic components of variance and covariance under selection are discussed, with special attention to likelihood methods. Certain selection processes are described and alternative likelihoods that can be used for analysis are specified. There is a mathematical relationship between the likelihoods that permits comparing the relative amount of information contained in them. Theoretical arguments and evidence indicate that point inferences made from likelihood functions are not affected by some forms of selection.

Animals↗
PubMed1977

Metabolic studies on two patients with nonhepatic tyrosinemia using deuterated tyrosine loads.

Metabolic studies on two patients with defects in the tyrosine oxidation pathway are reported. Serum tyrosine was greatly elevated in both patients (1.37 and 1.52 mmol/liter, respectively) and both excreted large quantities of p-hydroxyphenylacetic acid, p-hydroxyphenyllactic acid, and p-hydroxyphenylpyruvic acid. Deuterated tyrosine loads were administered to both patients, before and after lowering of the serum tyrosine concentration by dietary treatment, and to a normal adult control subject. In one patient the excretion of the deuterated (D2)-tyrosine load was more than 300 times that found in the control subject whether the test was done at high or low serum tyrosine level and the pattern of metabolites indicated a persistent defect in p-hydroxyphenylpyruvic acid oxidase. Enzyme assays on needle liver biopsy supported this finding. In the second patient excretion of the D2 label was 300 times that of the control at high serum tyrosine levels, but only 5 times normal at low serum tyrosine levels. This finding was interpreted as indicating substrate inhibition of p-hydroxyphenylpyruvic acid oxidase. The primary defect has not been established in this patient, but the findings are compatible with a defect in hepatic-soluble tyrosine aminotransferase.

4-Hydroxyphenylpyruvate Dioxygenase↗