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Biomedical subjects

Y K Park

Publications and source records attributed to Y K Park.

At least 19 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↗
PubMed1992

Nutrient intakes and body weights of persons consuming high and moderate levels of added sugars.

We classified a nationally representative sample of persons aged 4 years and older as high or moderate consumers of added sugars (ie, sugars added to foods by processors or consumers). Intake of added sugars was determined on the basis of grams consumed per kilogram of body weight (g/kg) and on the basis of percent of dietary energy from added sugars (% kcal). Regardless of the intake measure used, high consumers of added sugars had a significantly lower percentage of dietary energy from fat than did moderate consumers of added sugars. Persons defined by the % kcal measure as high consumers of added sugars took in lower percentages of the Recommended Dietary Allowances (RDAs) for 11 vitamins and minerals; these high consumers had body weights similar to those of their moderate counterparts. Persons defined as high consumers by the g/kg measure consumed greater percentages of the RDAs than did their moderate counterparts; these high consumers more frequently selected foods from categories likely to contain sugar-rich foods but weighed significantly less than did moderate consumers. Thus, different approaches to defining intake of added sugars revealed two patterns of high consumption of added sugars with different levels of nutritional risk. Conditions of overweight were not associated with high intake of added sugars. Educational efforts, therefore, should focus on those consumers who tend to substitute foods rich in added sugars for more nutritionally desirable foods.

Adolescent↗
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

Characteristics of vitamin and mineral supplement products in the United States.

A 1986 nationwide survey of 11,775 adults 18 y or older and 1877 children 2-6 y old identified approximately 3400 different (unique) vitamin and mineral supplement products being taken. The most commonly included nutrient listed on the product labels was vitamin C, which was present in 50% of the unique products examined. Calcium and iron were the most commonly included minerals and were present in 25% of the unique products examined. Prenatal and children's chewable products came in a relatively narrow potency range and generally contained nutrients in amounts approximating or less than the US recommended daily allowances. These products also contained significant minimum amounts of nutrients. Potencies of products not targeted for use by these special groups, particularly those products that were self-prescribed, varied widely and ranged from insignificant to extremely large amounts of nutrients. Units used to declare product potency or to prescribe the dosage varied.

Adult↗
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

Giant cell tumor of the scapula associated with secondary aneurysmal bone cyst.

Giant cell tumors are distinctive neoplasms characterized by a profusion of multinucleate giant cells scattered throughout a stroma of mononuclear cells. Most giant cell tumors are found at the epiphyses of long bones, especially around the knee joint. Flat bone involvement is rare. However, a case of giant cell tumor with secondary aneurysmal bone cyst was encountered at the scapula of a 25-year-old man. Since the occurrence of a giant cell tumor with secondary aneurysmal bone cyst on flat bones (i.e., the scapula) is extremely rare, the above-mentioned case is worthy of reporting.

Adult↗
PubMed1991

Pedunculated leiomyoma of scrotum.

Leiomyoma may originate at any anatomic location of smooth muscle in the genitourinary system. The kidney capsule is the most common site for the genitourinary leiomyomas. Leiomyoma origination from the scrotum is rare. The previous reported cases presented as small, firm, nontender, slowly enlarging freely movable masses within the scrotum. We report a case of leiomyoma of the tunica dartos, a benign lesion arising from the wall of the left scrotum. It presented as a pedunculated lesion with a surface ulceration, which need to be differentiated from squamous carcinoma of the scrotum. It was treated with a simple surgical excision.

Carcinoma, Squamous Cell↗
PubMed1991

Study of the skin concentrations after administration of the various phototoxic drugs.

The skin concentrations of 8-methoxypsoralen (8-MOP), 5-methoxypsoralen (5-MOP), and 4, 5', 8-trimethylpsoralen (TMP) were studied in the guinea pig following oral administration and bathing. The skin concentration of phototoxic drugs after oral administration peaked at 1.5 hours, and the concentration of 8-MOP was 3.5 times greater than that of 5-MOP. The skin concentration of TMP was not detected in our study (limit of sensitivity 5ng/ml). The skin concentrations of phototoxic drug after bathing decreased in the order of 5-MOP, TMP, and 8-MOP.

Administration, Cutaneous↗
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↗
PubMed1991

Effects of maternal postural change from supine to left-lateral on tocolysis, maternal cardiac function and pulsatility index of uterine artery.

In order to prove the usefulness of the left-lateral position (l-lat.) in preventing the cardiovascular complications associated with ritodrine, twenty-nine patients having preterm labor were employed as the subjects of this study. Before and during the administration of ritodrine, the cardiac function was recorded by impedance cardiography. (1) When ritodrine was administered in the supine position, SV and CO first increased but eventually tended to decrease. When the position was changed to the l-lat. after SV and CO had almost returned to the preadministration level, HR decreased and SV and CO increased in 70% (10/14) of the patients. However, in patients showing no change in HR in the supine position, the cardiac function did not change either. (2) The magnitude of the changes in cardiac function accompanying the postural change during ritodrine administration was compared with that observed before administration. The decrease in HR and the increase in SV due to the postural change to the l-lat. were larger during ritodrine administration than before administration. The l-lat. position is recommended as a means for preventing the side effects accompanying ritodrine administration. This study also indicated the possibility that the inferior vena cava may be more strongly compressed in the supine position by the relaxed gravid uterus.

Cardiac Output↗
PubMed1991

Effect of left-lateral position on maternal hemodynamics during ritodrine treatment in comparison with supine position.

Pregnant women are generally recommended to rest in the left-lateral position (l-lat.) to avoid caval compression. We studied the influence of postural change from the supine position (sup.) to the l-lat. on maternal hemodynamics and tocolysis. The cardiac output (CO) was measured by impedance cardiography, while the pulsatility index of the uterine artery (PIUtA) was determined by the pulsed Doppler method. When the maternal posture was changed from sup. to l-lat, the following results were obtained. (1) The frequency of uterine contractions (UC) (preterm labor = 92) was significantly reduced (p less than 0.01). (2) The resting uterine tonus (n = 5) was also significantly decreased (p less than 0.05). (3) In the cases showing a decrease in the frequency of UC, the CO value was significantly increased (p less than 0.01), whereas PIUtA was significantly decreased (p less than 0.01). It is concluded that the postural change from sup. to l-lat. resulted in a decrease in the frequency of UC and the resting uterine tonus and at the same time an increase in the CO and decrease in the vascular resistance of the uterine artery.

Cardiac Output↗
PubMed1990

The effect of UVA irradiation on the epidermal melanocyte after 8-MOP and TMP administration.

Morphological and numerical changes in the epidermal melanocytes of black C57BL mice after phototoxic drug administration followed by ultraviolet A irradiation were studied to compare the effects of photochemotherapy on the epidermal melanocytes using 8-methoxypsoralen and trimethylpsoralen. One hour after intraperitoneal injection of the phototoxic drugs, 1.5 mg/kg in the small dose group and 6.0 mg/kg in the large dose group, the mice were exposed to UVA irradiation. This procedure was performed twice a week for 8 weeks at the small dose group and for 5 weeks in the large dose group. Skin biopsies were taken before irradiation in both groups, and follow up biopsies were done at each week. The number and size of the melanocytes were observed in a split-DOPA preparation. In the drug treated groups, there was an increase in the size of the perikaryon, and the number, length, width, and arborization of dendrites. Such changes were more clearly seen in the group treated with trimethylpsoralen compared with the 8-methoxypsoralen treated group. Therefore, trimethylpsoralen is more effective than 8-methoxypsoralen in the increase of the perikaryon size, and the number, length, width, and arborization of dendrites of melanocytes in the intraperitoneal injection.

Animals↗
PubMed1990

Trend changes in use and current intakes of tropical oils in the United States.

To evaluate the need for and potential public health impact of selective labeling of foods containing tropical oils (TOs), we examined trend changes in use of TOs in the United States from 1963 to 1985 and estimated current intakes of total fat (FI) and saturated fatty acids (SFAI) attributable to TOs. Although world production of TO has increased rapidly since 1970, use in the United States has not followed the world trend. A large portion of TOs in the United States was used in nonfood products. Estimates of current intake of TOs by selected US population groups revealed only minor contribution of TOs to the daily FI and SFAI in the United States. In 1985 the most reasonable estimate of the average FI from all three TOs represented less than 4% of total daily FI or less than 2% of daily energy intake. Three TOs combined contributed less than or equal to 8% to the daily SFAI of the three sex and/or age groups examined.

Adult↗