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Biomedical subjects

H C Wulf

Publications and source records attributed to H C Wulf.

At least 109 records · Page 6Linked to original sources
PubMed1995

Pigmentation-dependent side effects to copper vapor laser and argon laser treatment.

BACKGROUND AND OBJECTIVE: Melanin is a limiting factor for obtaining beneficial results in dermatological treatment of vascular malformations. The aim of our study was to establish a relation between pretreatment skin pigmentation and the occurrence of side effects. STUDY DESIGN/MATERIALS AND METHODS: Thirteen human volunteers selected to have a varying degree of skin pigmentation were laser-treated on the inside of the brachium with an argon laser (AL, 488 nm and 514.5 nm) and a copper vapor laser (CVL, 578 nm), both connected to a Hexascan. Total exposure areas were 1.26 cm2 and beam diameters were 1 mm. Three intensities were used, 0.7, 1.0, and 1.3 W. Pulse duration was 200 ms, resulting in fluences of 17.8, 25.5, and 33.1 J/cm2. Pretreatment skin pigmentation was objectified by skin reflectance measurements. RESULTS: At 1, 2, and 6 months after laser treatment, significant correlations were demonstrated between pretreatment skin pigmentation and laser-induced pigmentary changes and scar formation. At the 6-month assessment, the AL induced significantly higher scores of clinically evaluated scar formation as compared with the CVL (1.0 and 1.3 W/spot) and tended to induce higher clinical scores of pigmentary changes (not significant, ns). CONCLUSIONS: We recommend skin pigmentation to be taken into consideration in dermatological laser treatment of vascular malformations.

Adult↗
PubMed1995

Effects of systemic indomethacin on photocarcinogenesis in hairless mice.

The effect of systemic treatment with the anti-inflammatory drug indomethacin on sun-induced skin carcinogenesis was examined in lightly pigmented hairless hr/hr C3H/Tif mice. Two groups of 20 mice were exposed to simulated solar ultraviolet radiation from one Phillips TL 12 and five Bellarium-S SA-1-12 tubes for 8 min/day, 4 days/week (daily dose was 12.6 kJ/m2, equivalent to 2.1 B-MED the basic minimal erythema dose). A mean dose of 1.8 mg kg-1 24 h-1 indomethacin was supplied to one of the two groups via the drinking water. The pharmacological treatment started on the first day of the trial and continued during the entire experiment. The time to first, second, and third tumour was significantly delayed in the group treated with indomethacin (P < 0.001). The mortality rate was higher in the indomethacin-treated group than in the group receiving no pharmacological treatment (P < 0.0005). Under the present conditions, our study suggests that indomethacin may be beneficial in protection against photocarcinogenesis.

Animals↗
PubMed1995

Mast cells and elastosis in ultraviolet-irradiated hairless mice.

Earlier studies of ultraviolet (UV) irradiated hairless mice have suggested a relation between elastosis and mast cells. To examine whether such a relation exists, we examined groups of hairless mice irradiated with equal doses of UV. The narrow UV bands had peaks at 292, 300, 307, 317 and 336 nm. The groups were irradiated 5 times per week during 1 year. It was shown that the shorter the wavelengths, the more pronounced was the degree of elastosis. Sections from dorsal skin were prepared for light microscopy and stained with orcein, making it possible to detect the elastosis at the same time as the mast cells. We used a projection microscope and a computer analyzing system connected to a video scanner for the calculations. The mast cell count was higher in the irradiated groups than in the control group. The number of mast cells was higher in the groups irradiated with the shortest wavelengths (292 and 300 nm). In groups irradiated with wavelengths shorter than 307 nm a subepidermal clearance zone containing significantly fewer mast cells than the rest of the upper dermal layer was found. We suggest that the mast cells might have a digesting function, as this layer was cleared of elastotic fibers and few mast cells were seen here.

Animals↗
PubMed1995

In vivo estimation of pigmentation in ultraviolet-exposed hairless mice.

A new in vivo method of visual scoring of pigmentation in hairless hr/hr mice with a C3H/Tif background is described. The mice were placed under a bank of 6 Philips TL08 fluorescent ultraviolet A (UVA) tubes in a dark room, and the pigmentation of the skin was compared with a Kodak Gray Scale with 20 different shades from white to black. The radiation from the tubes changed both the color of the back of the mouse and the gray scale into purple hues. The purple color of the back of each mouse could then be classified as one of 20 shades on the gray scale. An experiment was conducted exposing 3 groups of 20 mice to different doses of UV radiation from Philips TL01 tubes. One group of 20 mice was not irradiated and served as control. The pigmentation of each mouse was scored by one investigator every 2-3 weeks. After a few weeks of exposure a clear distinction between the groups was seen. To evaluate the inter- and intrapersonal variation of the method, 30 mice with various degrees of pigmentation were scored independently and blindly by two investigators. This was done twice during the study with a few days' interval. No interpersonal difference was found, but one investigator scored differently the first and second time by only 0.5 points. The described method provides a reproducible in vivo method, with very good discrimination, for estimation of pigmentation in hairless mice.

Animals↗
PubMed1995

Carcinogenic and melanogenic effects of a filtered metal halide UVA source and a tubular fluorescent UVA tanning source with or without additional solar-simulated UV radiation in hairless mice.

The carcinogenic and melanogenic effects of a filtered metal halide source (UVASUN) that emits UV radiation in a range from 340 to 400 nm and a bank of Philips TL 09R tubes (TL 09) emitting in a range from 310 to 400 nm were studied in lightly pigmented hairless hr/hr C3H/Tif mice. Both the carcinogenic effect of the two UVA radiation sources alone and in combination with a UV source, consisting of one Philips TL 12 and five Bellarium-S SA-1-12 tubes emitting radiation somewhat similar to the UV part of the solar spectrum (SOLAR UV), were investigated. Finally, the melanogenic effect of exposure to the two UVA sources were studied. The mice were exposed to the UVA sources 30 min/day 5 days/week, in equal erythemogenic doses, calculated by using the Commission Internationale de l'Eclairage human erythema action spectrum. Equal erythemogenic doses of TL 09 and UVASUN induced the same degree of skin pigmentation, but skin tumor development was enhanced in mice exposed to TL 09 compared with UVASUN (P < 0.0005). For all but one tumor, endpoint pretreatment with TL 09 or UVASUN for 91 days did not influence tumor development during subsequent exposure to SOLAR UV radiation 10 min/day, 4 days/week. Exposure to the two UVA radiation sources after 91 days of SOLAR UV exposure significantly enhanced skin tumor development. Overall, the data on the interaction between exposure to the UVA sources and SOLAR UV indicated that the risk of SOLAR UV-induced carcinogenesis was independent of the type of prior-UVA exposure and post-UVA exposure.

Animals↗
PubMed1995

Plasma cell balanitis treated with a copper vapour laser.

A 48-year-old, uncircumcised man presented with plasma cell balanitis, which is a chronic, erosive dermatitis at the glans penis and the inner surface of the prepuce, which is normally treated by circumcision. He was treated with three sessions of copper vapour laser over a period of three months and apart from a minor relapse after seven months he has to our knowledge been well.

Balanitis↗
PubMed1994

[Sun and sun protection].

Protection against the sun in Denmark is only necessary from mid April to September. The number of erythema units may reach about 16 per day in the summer sun and about 50% of the biological active radiation is found between 12 a.m. and 3 p.m. (summertime). The most biologically active wavelengths are found to be 300-325 nm and protection with sunscreens and clothes should include these wavelengths. Necessary sun protection factors for average and especially sensitive Danes were estimated. The average Dane needs a SPF of 4-8 and especially sensitive persons a SPF of 8-15 when exposed all day in summer. Most clothes meet these demands.

Denmark↗
PubMed1994

Pigmentation dependent, short time skin reactions to copper vapour laser and argon laser treatment.

Thirteen human volunteers selected to have a varying degree of epidermal skin pigmentation were laser treated on the inside of the brachium in six hexagonal areas; three areas with an argon laser (AL, 488, 514.5 nm) and three corresponding areas with a copper vapour laser (CVL, 578 nm). The lasers were connected to a Hexascan device and the physical settings were identical for the two laser types, except for the wavelengths. Beam diameter was 1 mm, pulse duration 200 ms, intensities 0.7, 1.0 and 1.3 W/spot, corresponding to 14.1, 20.2 and 26.2J/cm2 per treated skin area. The skin pigmentation was objectified by skin reflectance. A correlation was demonstrated between skin pigmentation and wound healing time, maximum wound area, and the acute clinical response at days 0, 1, 4, 7, 11 and 17 after laser treatment. An increased skin pigmentation resulted in increased acute and subacute skin reactions. Comparison of the AL and the CVL demonstrated that the CVL on day 0 (0.7 and 1.0 W/spot) and on day 1 (0.7 W/spot) induced a significantly higher degree of skin reactions as compared with the AL. At 0.7 W/spot the CVL induced a significantly higher maximum wound area and a significantly prolonged wound healing time as compared with the AL. An inverse reaction existed between pigmentation and the threshold intensity required to induce wound formation.

Adult↗
PubMed1994

Near-visible-UV radiation delays UVB tumorigenesis.

The effect of UVA radiation (321-400 nm) on UVB photocarcinogenesis was examined in lightly pigmented hairless hr/hr C3H/Tif mice. Five groups of 22 mice were exposed to UVB radiation (281-320 nm) from one Philips 12 tube for 10 min per day and 4 days per week. Four of the groups were simultaneously exposed to UVA from two to six filtered Philips 09 tubes. The daily dose of UVB was 2.0 kJ m-2 in all five groups; the UVA2 (321-340 nm) dose varied from 0.7 to 4.5 kJ m-2 and the UVA1 (341-400 nm) dose from 0.3 to 45.6 kJ m-2. A sixth group was exclusively irradiated with the filtered UVA tubes and served as a control. Skin tumor development was not significantly different for the groups exposed to the UVB source alone or the UVB source in combination with the largest daily UVA dose (0.2 > p > 0.1). Skin tumor development was significantly delayed in the other groups irradiated with the UVB source and the lower doses of UVA (p < 0.001). No tumors were observed in the control group. This study suggests that UVA1 radiation delays UVB-induced skin tumor development. However, the delay cannot be expected to persist when UVA is administered in higher daily doses.

Animals↗
PubMed1994

A polychromatic action spectrum for photosensitivity to orally administered 8-methoxypsoralen in humans.

The action spectrum for producing minimal phototoxic erythema after oral administration of 8-methoxypsoralen (8-MOP) was determined in the range of 312-368 nm in 12 human volunteers using six different UV radiation sources. The peak sensitivity was found to be at 343 nm. The 8-MOP photosensitivity was at a high level (> or = 0.75 of maximum) between 336 and 355 nm. Conventional UVA radiation sources, like the Philips TL/09R tube, have a high energy output within 335 and 355 nm, and are therefore highly recommended in oral psoralen plus UVA radiation treatment.

Administration, Oral↗
PubMed1994

8-methoxypsoralen increases daytime plasma melatonin levels in humans through inhibition of metabolism.

It is well established that in healthy humans oral intake of 5- or 8-methoxypsoralen (5- and 8-MOP) is followed by a significant increase in plasma melatonin concentrations. The effect of psoralen on rat melatonin has been studied in vitro and in vivo and a stimulation of release or secretion from the pineal gland has been suggested. In this study we examined the time-related changes in plasma concentrations of 8-MOP, melatonin and 6-sulfatoxymelatonin in 15 patients admitted for routine psoralen plus UVA therapy. On the first day of treatment blood samples were collected before, and 30, 60, 66 and 90 min after intake of 8-MOP (0.6 mg/kg). Although the rate of 8-MOP absorption varied greatly, a significant increase (P = 0.0002) in melatonin levels was found 60 min after 8-MOP intake. During UVA exposure a strongly correlated decrease in mean melatonin and mean 8-MOP concentrations was found, indicating an effect of UVA radiation, either direct or 8-MOP mediated, on circulating melatonin levels. Plasma 6-sulfatoxymelatonin concentrations decreased significantly between all time points, suggesting inhibition of melatonin metabolism.

Adult↗
PubMed1994

Differences in narrow-band ultraviolet B and broad-spectrum ultraviolet photocarcinogenesis in lightly pigmented hairless mice.

The carcinogenic effect of 4 ultraviolet (UV) sources was studied in lightly pigmented hairless mice. Two narrow-band UV sources, Philips TL01 and Philips TL12 with a Tempax filter, and two broad-spectrum UV sources, Philips TL12 and Bellarium S, were used. Exposure doses were calculated from the CIE erythema action spectrum. Four groups of mice (n = 20) were exposed to a nonerythemogenic dose (low dose), and 4 groups were exposed to an erythemogenic dose (high dose) of each of the 4 UV sources. One group (control) was not irradiated. The mice in the 4 low-dose groups were all exposed to 0.6 basic minimal erythema doses (B-MED) 5 days/week, and all the mice in the high-dose groups to 1.2 B-MED 5 days/week. After 16 weeks of acclimatization, the doses were doubled. Bellarium S and Philips TL12 were equally carcinogenic in the low-dose regimen and the high-dose regimen. Mice exposed to Philips TL12 with a Tempax filter developed tumors significantly earlier compared with Bellarium and Philips TL12. Philips TL01 was more carcinogenic than any of the other UV sources. Equally erythemogenic doses calculated from the CIE erythema action spectrum seem to be more carcinogenic when derived from narrow-band UVB sources than from broad-band UV sources.

Acclimatization↗
PubMed1994

A quantitative study of the melanogenic effect of multiple suberythemal doses of different ultraviolet radiation sources.

The melanogenic potential of multiple suberythemogenic doses of 6 different ultraviolet (UV) sources was investigated. The UV sources emitted different amounts of UVA and UVB. The backs of 12 volunteers were exposed to the 6 UV sources 10 times during 4 weeks. Every volunteer was exposed to the same suberythemogenic dose (0.75 basic minimal erythema dose) of each of the UV sources. The changes in pigmentation and minimal erythema dose of the UV exposed test sites were registered during the 10 sessions. Three UVA sources with a low emission in the UVB area (0.2-3.1%) had a high melanogenic potential. Two UVB sources (UVB emission 74.3% and 94.5%) were unable to induce a significant increase in skin pigmentation. The 3 UVA sources with a low UVB output increased skin pigmentation significantly better than a UVA source with a UVB output of 6.9%. All 6 lamps were able to increase photoprotection significantly. The increase in photoprotection was not significantly different between any of the 6 UV sources. This study shows that, if humans are exposed to equally suberythemogenic doses of different types of UV radiation, then radiation obtained from UVA sources greatly enhances melanogenesis, whereas UVB radiation sources are unable to induce pigmentation.

Adult↗
PubMed1994

Skin pigmentation as a predictor of minimal phototoxic dose after oral methoxsalen.

BACKGROUND AND DESIGN: Twenty-eight subjects were phototested to determine their erythemal responses to oral methoxsalen with UV-A and UV-B irradiation. Skin pigmentation was measured by skin reflectance at 550 and 660 nm before irradiation. The smallest UV radiation dose to produce erythema (minimal phototoxic dose and minimal erythema dose, respectively) was determined. The serum concentration of methoxsalen was measured at the time of UV-A irradiation. RESULTS: There was a positive correlation between skin pigmentation and both 72-hour minimal phototoxic dose and 24-hour minimal erythema dose. No correlation was demonstrated between methoxsalen serum concentration and minimal phototoxic dose. The combination of skin pigmentation and methoxsalen level did not give a better prediction of minimal phototoxic dose than skin pigmentation alone. CONCLUSIONS: Skin pigmentation measurements can be used to predict the minimal phototoxic and erythema doses. Skin pigmentation measurements are easy to perform and should be included in both phototherapy and photochemotherapy to improve the efficiency and reliability of the treatment.

Administration, Oral↗