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H C Wulf

Publications and source records attributed to H C Wulf.

At least 73 records · Page 4Linked to original sources
PubMed1998

Ultraviolet exposure influences laser-induced wounds, scars, and hyperpigmentation: a murine study.

Laser therapy is today considered the treatment of choice for vascular skin lesions, which commonly are located on the face and, therefore, frequently are exposed to sunlight. The purpose of this study was to examine whether preoperative and postoperative ultraviolet irradiation influences the development of laser-induced side effects. We laser-treated hairless mice with a copper vapor laser; three different intensities were used at a constant pulse duration. Simulated solar ultraviolet radiation was administered either before the laser treatment (3 consecutive days, daily doses of 2.48 J/cm2) or after the laser treatment (four times weekly in 4 weeks, daily doses of 1.66 J/cm2). Laser-induced wounds, scars, and hyperpigmentation were evaluated by macroscopic, histologic, and biochemical examinations. Preoperative ultraviolet exposure enlarged the laser-induced wounds and the areas with texture change at some of the laser intensities used. However, the most pronounced effect was seen for postoperative ultraviolet-irradiated mice. These mice developed, at some of the laser intensities, a higher incidence of bulging infiltration as well as higher degrees of fibrosis and hyperpigmentation, thus developing a poor cosmetic appearance. Furthermore, ultraviolet irradiation after laser treatment resulted in slowly healing wounds of reduced size, indicating deep, constricted skin damage. We conclude that ultraviolet exposure before and after copper vapor laser treatment increases the risk of inducing side effects from dermatological laser treatment.

Animals↗
PubMed1998

A UVB phototherapy protocol with very low dose increments as a treatment of atopic dermatitis.

From 1991 to 1992, 15 patients with atopic dermatitis were treated with a new UVB treatment regimen guided by skin reflectance measurements. The new treatment was characterized by very low dose increments from start to end of therapy. The median cumulative dose increment during therapy was only 20%. The severity of the disease, the efficacy of the treatment, the occurrence of adverse effects and the cumulative UVB dose were obtained from the case records. This data were compared in an open study with the data obtained from 17 patients with atopic dermatitis who were treated from 1988 to 1991 at the department with a standard UVB treatment regimen with stepwise dose increments. There was no difference in the severity of the disease at the beginning of the therapy between the two groups. The skin reflectance-guided low-dose UVB therapy was not significantly faster (3.5 weeks) than the regimen with stepwise dose increments (4.5 weeks). The cumulative UV exposure was four times lower with the new treatment regimen (34 standard erythema doses) compared with the old regimen (161 standard erythema doses), P<0.001. The healing score was significantly higher with the new treatment regimen compared with the old, P<0.05. This study indicates that skin reflectance-guided UVB phototherapy may enable the dermatologist to lower the cumulative UVB exposure significantly without losing effect.

Adult↗
PubMed1998

Skin pigmentation in Caucasian babies is high and evenly distributed throughout the body.

To investigate if Caucasian babies have particular sun sensitive skin and if skin pigmentation before any sun exposure is uniform throughout the body, we measured skin pigmentation objectively by skin reflectance spectroscopy in 10 anatomical sites in 20 healthy Caucasian babies (mean age 5 months, range 1 to 10 months) that had not been sun exposed previously. We found that skin pigmentation at all the measured sites was significantly higher than the constitutive pigmentation in Caucasian adults (P < 0.01). Furthermore, the level of skin pigmentation in all the 10 measured sites in the babies was statistically not different (P < 0.31) and there was no gender differences in pigmentation for any site.

Adult↗
PubMed1998

High MHC class I expression correlates with slow growth in UV-induced skin carcinomas in hairless mice.

An experiment was set up to investigate the relationship, if any, between cell surface MHC class I expression and the growth rate for skin tumors induced by two different UV radiation regimens in hairless mice. Two groups of 20 hairless mice were each irradiated with either a UVA radiation source (2 SED per session) or broad-spectrum UV radiation (UVB) (8.1 SED per session) 5 days a week during the entire experiment. In the UVA group, 17 out of 20 animals developed tumors, and 10 of these grew to a diameter of > or = 5 mm. In the UVB group, 19 out of 20 animals developed tumors, and 15 of these grew to a diameter of > or = 5 mm. The tumor induction time, i.e. the time from the start of UV treatment to tumor appearance, was found to be significantly longer (p<0.01) in the UVA than in the UVB group. This is in accordance with previous findings. Of the 25 tumors growing to a diameter of > or = 5 mm, 11 were established as cultured cell lines (4 UVA and 7 UVB tumors). These uncloned cell lines were analyzed for surface expression of major histocompatibility complex class I by FACS analysis. There was a clear correlation between high MHC class I expression and slow growth of the individual tumors (p<0.05). This suggests a role for the MHC class I governed, i.e. cytotoxic T-cell-mediated, reactions in deciding the fate of UV-induced skin cancers. No correlation was found between MHC class I expression and tumor induction time.

Animals↗
PubMed1998

Melanin and melanosome complexes in long standing stable vitiligo--an ultrastructural study.

To investigate the presence of melanin and melanocytes (MC) in stable vitiligo, skin biopsies from five patients with vitiligo lesions of between 1 to 17 years duration were examined under the electron microscope. Areas of the upper dermis and epidermis were explored. There was a significant amount of melanin in a few keratinocytes (KC) grouped in the stratum basale in 1-3 year-old vitiligo lesions. In these KC, the melanosomes were most often aggregated into melanosome complexes (MCo) while the remaining KC were completely devoid of melanin. Solitary MCo were also observed in a few dermal cells in all vitiligo biopsies. All non-keratinocytes were scrutinized in series of 200-300 consecutive sections and were identified according to morphological characteristics. Neither active nor inactive MC, nor MC dendrites were found. These observations show that melanin in non-negligible amounts can be found even in 3 year-old vitiligo epidermis. Since there were no MC detected in the epidermis it implies that the melanosomes can persist in certain KC for some time after the onset of vitiligo.

Adolescent↗
PubMed1997

[Dermatological laser treatment. A review of therapeutic possibilities and equipment].

Laser light is monochromatic light that is delivered either in order to perform a precise thermal destruction of specific skin components or in order to ablate skin in an unspecific, but highly controlled way. Optimal dermatological laser treatment requires carefully selected laser wavelengths for specific indications. It is recommended that laser treatment of vascular lesions such as naevus flammeus and haemangiomas is carried out in early childhood. In laser treatment of benign, pigmented lesions it is important to distinguish between epidermal and dermal lesions, since treatment response as well as optimal laser wavelengths depend on this subclassification. The treatment of tattoos is undertaken by different laser types, of which the most optimal can be selected by skin reflectance measurements. Novel fields of indications for dermatological laser therapy are verrucae vulgares, erythematous hypertrophic scars, undesired hair growth, and wrinkled, photoaged facial skin.

Humans↗
PubMed1997

Risk assessment of side effects from copper vapor and argon laser treatment: the importance of skin pigmentation.

BACKGROUND AND OBJECTIVE: Epidermal melanin is a limiting factor for obtaining beneficial results in dermatological treatment of vascular malformations. The aim of our study was to predict the highest laser intensity and energy fluence which can be applied to skin with different degrees of pigmentation before side effects are induced. STUDY DESIGN/MATERIALS AND METHODS: Thirteen human volunteers with different degrees 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. Three input intensities were used. 0.7, 1.0, and 1.3 W. Pulse duration was kept constant at 200 msec, resulting in hexascan fluences of 14.1, 20.2, and 26.2 J/cm2. At the 6-month assessment it was noted whether pigmentary changes or scarring were clinically absent or present. The results were analysed by logistic regression. RESULTS: We found that pretreatment pigmentation percentage and laser intensity were significant risk factors of inducing side effects (P < .001), whereas it was without significant importance whether the AL or the CVL was used (P > .05). Contour lines of 1, 2.5, 5, 10, 25, and 50% risk levels of inducing clinically recognizable pigmentary changes and scarring were calculated. Pigmentary changes occurred at a significantly lower intensity level than skin texture changes (P = .006). CONCLUSION: On basis of our results, we recommend assessment of skin pigmentation prior to laser treatment with the CVL and the AL, and we recommend that the illustrated risk levels are taken into consideration.

Adult↗
PubMed1997

Side effects from dermatological laser treatment related to UV exposure and epidermal thickness: a murine experiment with the copper vapor laser.

BACKGROUND AND OBJECTIVE: The intention of the present study was to clarify whether UV-exposure prior to laser treatment of albino mouse skin may influence laser-induced side effects and if a possible influence may be explained by epidermal thickening. STUDY DESIGN/MATERIALS AND METHODS: Albino, hairless mice were irradiated 0, 8, and 22 consecutive times with simulated solar UV (1.4 J/cm2 per treatment). Subsequently, two areas on the back of the mice (1.26 cm2 each) were treated with a copper vapor laser that was connected to a Hexascan. The beam diameter was 1 mm, pulse duration 200 msec, and intensities 0.6 W, 0.8 W, and 1.0 W. Laser-induced wounds, scars, and histologically evaluated fibrosis were evaluated. RESULTS: We found that mice irradiated with UV before laser treatment developed smaller wounds, smaller texture change areas, and less fibrosis as compared with nonirradiated control groups, and significant, negative correlations were demonstrated between epidermal thicknesses (stratum corneum, the cellular part of epidermis, and the entire epidermis) and laser-induced skin reactions. A dose response was obtained between laser intensities and laser-induced skin reactions, which tended to be more severe in the cranial back location as compared with the caudal back location. Epidermal layers increased significantly after eight consecutive times of UV irradiation and increased to a steady level after 22 times of irradiation. CONCLUSION: We conclude that UV exposure prior to laser treatment of albino mice reduced laser-induced side-effects, which could be explained by increased epidermal thickening. Variations in epidermal thickness might thus contribute to variations in clinical response to dermatological laser treatment with the copper vapor laser.

Animals↗
PubMed1997

Urocanic acid isomers: relation to body site, pigmentation, stratum corneum thickness and photosensitivity.

Urocanic acid (UCA), present in the stratum corneum as trans-UCA, absorbs ultraviolet (UV) radiation and isomerizes to cis-UCA. Cis-UCA has been demonstrated to initiate suppression of selected immune responses in several experimental systems. Topical application of UCA-containing products reduces UV-induced erythema, but a role for endogenous UCA in photoprotection has not been reported. In this study the relationship between UCA isomers, pigmentation, minimal erythema dose (MED), and stratum corneum thickness was investigated. Pigmentation, concentration of total UCA, and the percentage present as the cis-isomer was measured in 36 healthy subjects, skin type I-IV, at six UV-exposed and nonexposed body sites: forehead, chest, back, outer upper arm, inner upper arm, and buttock. The MED was determined by phototesting on buttock skin, and a punch biopsy for measurement of stratum corneum thickness was taken adjacent to the site of the phototest. The percentage of cis-UCA was significantly higher in UV-exposed than on nonexposed areas. A small intraindividual variation in total UCA was found, being high on the buttock and the arm, lowest on the forehead. The subject to subject variation of total UCA was considerable at all body sites. No correlation was found between total UCA and MED, skin type, pigmentation, or stratum corneum thickness.

Adolescent↗
PubMed1997

UV induced erythema evaluated 24 h post-exposure by skin reflectance and laser Doppler flowmetry is identical in healthy persons and patients with cutaneous malignant melanoma and basal cell cancer.

Twenty-one patients with invasive cutaneous malignant melanoma and 19 patients with basal cell skin cancer and 29 healthy volunteers were phototested on non-UV exposed buttock skin to examine their 24 h reaction to a series of increasing doses of simulated sunlight with 25% dose increments. Skin pigmentation at the phototest sites was determined by skin reflectance before testing to assure an equal level of constitutive skin pigmentation in the 3 groups. Erythema reactions were scored visually 24 hours post-exposure and objective measurements of erythema were performed by skin reflectance and laser Doppler flowmetry. In adjacent non-irradiated skin the redness was also quantified to determine the increase in redness in irradiated skin compared to non-irradiated skin. Constitutional skin pigmentation correlated well to UV sensitivity (r = 0.75) and skin redness measured by skin reflectance technique correlated to laser Doppler flowmetry (r = 0.86). No significant differences in UV doses to barely perceptible erythema or to the higher erythema grades were found between the two skin tumour groups and the control group, and no significant differences were found in skin reflectance measured redness or in laser Doppler flowmetry of any erythema reactions between the 3 groups. The 24 h erythema reaction to sunlight can therefore not be used to distinguish patients with invasive cutaneous malignant melanoma or basal cell carcinoma from normal persons.

Erythema↗
PubMed1997

Two pathways for induction of apoptosis by ultraviolet radiation in cultured human keratinocytes.

Loss of attachment may induce apoptosis in epithelial cells, but it is unclear whether substrate adhesion modulates apoptosis triggered by genotoxic agents such as ultraviolet radiation (UV). To investigate this issue, we plated neonatal human keratinocytes on different substrates and irradiated them with UVB. DNA strand breaks were nick-labeled to identify apoptotic nuclei. Keratinocytes grown in monolayers were less susceptible to UV-induced apoptosis than were cells freshly seeded on glass (ED50 2130 +/- 96 J per m2, mean +/- SD, versus 131 +/- 96 J per m2, mean +/- SD, respectively). This phenomenon depended on differences in integrin-mediated adhesion, because blocking of integrin beta1 with a monoclonal antibody increased sensitivity of keratinocyte monolayers to UV and an increase in beta1 integrin receptor occupancy by plating on fibronectin, type IV collagen, or keratinocyte-derived extracellular matrix diminished the UV-dependent apoptosis. Down-regulation of p53 with an anti-sense oligonucleotide did not affect apoptosis in glass-plated keratinocytes but effectively suppressed apoptosis in keratinocytes adhering via beta1 integrin. Thus, in addition to the known p53-dependent pathway, UV was able to induce a p53-independent apoptosis that could be blocked by integrin-mediated cell attachment (the integrin-sensitive pathway). The susceptibility to the p53-dependent apoptosis, but not to the integrin-sensitive process, varied among keratinocytes of different clonogenic potential: transit amplifying cells > stem cells > terminally differentiated cells. The p53-independent integrin-sensitive apoptotic pathway may provide an additional mechanism counteracting UV carcinogenesis in the skin.

Adhesins, Bacterial↗
PubMed1997

Sunscreens used at the beach do not protect against erythema: a new definition of SPF is proposed.

Since sunscreens are recommended by doctors and used all over the world to protect against sun induced erythema, it is important to evaluate if sunscreens are used as recommended and if the intended effect is achieved. We refer to the findings of several studies performed on people at risk of sun-burning at beaches in the vicinity of Copenhagen, Denmark. On a sunny day at the beach 65% of the sunbathers used one or more sunscreens. Of these, 46% used the sunscreen all over the body and a median sun protection factor (SPF) of 5-6 was used. The sunbathers used 0.5 mg/cm2 of sunscreen independent of skin type. Of the sunscreen users, 43% applied the sunscreen after arriving at the beach and 43% reapplied the sunscreen after swimming. The sun exposure time and the sun exposure dose were almost identical among sunscreen users and non-users. Self-assessed redness of the skin demonstrated that more sunscreen users than non-users reported to be red the day after sun exposure, 42 and 34%, respectively. Theoretical calculations support this findings and show a drastic reduction in the achieved photoprotection if a thinner layer than in the test situation is used. Sunscreens do not protect against erythema if not used as intended. Instead of changing people's habits, we suggest modifying the test method by adjusting the amount of sunscreen to that used in real life situations, 0.5 mg/cm2.

Administration, Cutaneous↗
PubMed1997

Epidermal thickness, skin pigmentation and constitutive photosensitivity.

The important factors for UV sensitivity in humans are considered to be the skin pigmentation and the epidermal thickness. In this study on 73 Caucasians (age 20-85 years), we investigated in UV unexposed buttock skin the relationship between the UV sensitivity and constitutive skin pigmentation and thickness of the stratum corneum and the cellular part of the epidermis, in 34 normal people and in 39 skin cancer patients (20) patients with cutaneous malignant melanoma and 19 patients with basal cell carcinoma of the skin). Skin pigmentation was measured by skin reflectance spectroscopy, and UV sensitivity by phototest with a solar simulator. Thicknesses of the stratum corneum and the cellular part of the epidermis were determined by light microscopic evaluation of skin biopsies from the phototest areas. We found that epidermal thickness was independent of skin type and was not correlated to constitutive skin pigmentation. Thickness of the stratum corneum was statistically not different in normal persons and in skin cancer patients (P = 0.41) and was independent of gender (P = 0.61) and age (P = 0.56), while thickness of the cellular epidermis decreased with age (P < 0.01). Stratum corneum thickness was found to be of minor importance for the constitutive UV sensitivity (accounting for on average 11% of the total photoprotection), which was mainly determined by the constitutive skin pigmentation (goodness-of-fit for correlation r = 0.83). A theoretical model for the relationship of UV dose to induction of clinical erythema grade and skin pigmentation and thickness of the stratum corneum was developed. Objective measurements of skin pigmentation in UV unexposed skin by skin reflectance spectroscopy in Caucasians, normal people and people with cutaneous malignant melanoma and basal cell carcinoma of the skin predicts the constitutive UV sensitivity with a high degree of precision.

Adult↗
PubMed1997

Seasonal variation in urocanic acid isomers in human skin.

Urocanic acid (UCA) is a major chromophore for UV in the skin and has been suggested to act as an initiator of UV-induced immunosuppression. It converts from the naturally occurring trans-isomer to the cis-isomer on UV exposure. Isomerization is dose dependent until the photostationary state is reached, and the seasonal variation in irradiance from the sun may lead to changes in the percentage of UCA present as cis-UCA throughout the year. Thirty young healthy subjects, skin types I-IV, were followed from early summer till spring. At each of six visits (June, July, August, October, December, March), pigmentation and the concentration of UCA isomers were measured at six body sites: forehead, upper chest, upper back, outer upper arm, inner upper arm and buttock. In exposed as well as unexposed regions a variation in pigmentation was found, peak values being recorded in August. Total UCA concentration was lower in July and August than in the rest of the year, irrespective of body site. In July, the percentage of cis-UCA was close to the maximal obtainable (50-60%) at all sites except the buttock. In the three winter months the percentage of cis-UCA was below 7% in all regions except for the forehead, where the mean cis-UCA was 18% in October and March. No consistent relationship was found between UCA isomers and pigmentation or skin type.

Adolescent↗
PubMed1997

Distinctive molecular abnormalities in benign and malignant skin lesions: studies by Raman spectroscopy.

Near-infrared Fourier transform Raman spectroscopy is an analytical, nondestructive technique that provides information about the molecular structure of the investigated sample. The molecular structure of proteins and lipids differ between neoplastic and normal tissues and therefore Raman spectroscopy has been considered promising for the diagnosis of cancer. We aimed to compare the molecular structure of normal skin, benign and malignant skin lesions by the near-infrared Fourier transform Raman spectroscopy. Biopsies were obtained from the following skin lesions: skin tag, dermatofibroma, seborrhoeic keratosis, actinic keratosis, keratoacanthoma, basal cell carcinoma, squamous cell carcinoma, nevus intradermalis, nevus compositus, dysplastic nevus and lentigo maligna. Control skin was harvested from the vicinity of these lesions. In the Raman spectra, the secondary structure of the proteins was reflected by the amide vibrations of peptide bonds. The principal lipid vibrations were twisting and wagging (CH2) and CH stretching vibrations. Histologically distinguishable lesions showed specific combinations of band changes indicating alterations in the protein conformation and in the molecular structure of the lipids. Histogenetically related lesions (actinic keratosis and sqamous cell carcinoma) produced similar but not identical patterns of spectral changes. Because the examined skin lesions produced reproducible and unique spectra, we suggest that Raman spectroscopy will be useful for diagnosis of skin lesions.

Humans↗