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Biomedical subjects

H C Wulf

Publications and source records attributed to H C Wulf.

At least 127 records · Page 7Linked to original sources
PubMed1994

Erythema after irradiation with ultraviolet B from Philips TL12 and TL01 tubes.

A trial was conducted to investigate whether the experimentally found erythema caused by irradiation from Philips TL12 (TL12) and Philips TL01 (TL01) tubes corresponded to the expected erythema efficacy calculated from the CIE erythema action spectrum. Using the CIE erythema action spectrum and the emission spectra of the two tubes, the ratio between the calculated erythema efficacy of the two tubes is TL12:TL01 = 1:4.2. Seventeen volunteers were irradiated on previously unexposed buttocks with TL12 and TL01 in doses ranging from 0.8 to 3.3 kJ/m2 and from 3.1 to 18.6 kJ/m2 respectively. The erythema was evaluated clinically and measured by skin reflectance before and 24 h after exposure. Also the pigmentation of the skin was measured before exposure. The erythema efficacy ratio between TL12 and TL01 was found to be 1:2.8. This indicates that TL01 is more or TL12 is less potent than should be expected from the CIE erythema action spectrum and that this should be taken into account when changing from TL12 to TL01 in therapy.

Dose-Response Relationship, Radiation↗
PubMed1994

Scratching and ultraviolet irradiation: an experimental animal model.

The purpose of the study was to establish a useful animal model for quantification of itching and to examine whether the wavelengths inducing itching were identical to those inducing erythema. Four groups of hairless mice were irradiated with 4 different light sources in order to provoke itch. The light sources were adjusted to give equal erythrogenic doses. The groups were treated 5 times weekly for a year. For the first 16 weeks the daily dose was 0.6 minimal erythema dose (MED) and for the following 36 weeks 1.2 MED. The severity of the itching in the 4 groups and in a control group of untreated mice was compared. The chosen parameters were the number of scratch-sequences and the summarized time of scratching during an observation period of 1 h. Ultraviolet irradiation provoked itching. Especially the wavelengths 315-330 nm were more itch-provoking than erythemogenic. The difference between the control group and a group treated with Philips TL12 combined with a Tempax filter was significant. An action spectrum of itching does not seem to be identical to the erythema action spectrum. The animal model described is usable to quantify itch but has to be simplified. Of the lamps used, Philips TL01 was the least itch-provoking lamp type and may be preferred in the treatment of itching diseases.

Animals↗
PubMed1993

Laser induced wounds and scarring modified by antiinflammatory drugs: a murine model.

Scarring is a well-known side effect to cutaneous laser treatment. Therefore we investigated if wounds and scarring could be decreased by pharmacological interference in the acute inflammatory reaction following laser therapy. A copper vapor laser operating at 578 nm was used at three different intensities and doses. The antiinflammatory drugs methylprednisolone (1 mg/kg/24 h) and indomethacin (2 mg/kg/24 h) were administered through the drinking water. The laser induced wounds were evaluated daily and histologic and biochemical analyses were used to estimate scarring. The administration of antiinflammatory drugs resulted at some laser intensities in increased scores of maximum wound area, healing time, cumulated wound area, fibrosis, hydroxyproline, and hydroxylysine, being mostly pronounced for indomethacin at 0.8 W/spot. The maximum wound area and the wound healing time could be used as a predictor of scarring. A dose response was shown between the laser intensities and the mentioned parameters. We recommend carefulness in the laser treatment of patients receiving indomethacin and disrecommend use of the drug in the prophylaxis against laser induced scarring.

Administration, Oral↗
PubMed1993

Side effects of laser therapy, modified by ultraviolet irradiation and para-aminobenzoic acid in mice.

Scarring is a well-known side-effect of cutaneous laser treatment and exposure to solar ultraviolet radiation is suspected to increase scar formation. We investigated how wounds and scarring were modified by interfering in the laser-induced inflammation using ultraviolet radiation and para-aminobenzoic acid. A copper vapour laser operating at 578 nm was used at three different intensities and doses. The ultraviolet radiation was administered three times weekly prior to and four times weekly after the laser treatment. The daily dose was 21.5 kJ/m2 equivalent to 3.5 Basic-MED. The laser-induced wounds were evaluated daily and histological and biochemical analyses were used to estimate scarring. Ultraviolet irradiation resulted at some of the used laser intensities in decreased scores of maximum wound area, wound healing time, cumulated wound area, and a decreased skin content of hydroxyproline, whereas the degree of the chronic fibrosis tended to increase. Application of para-aminobenzoic acid before the solar ultraviolet irradiation did not change the acute wound scores but reduced, although not significantly, the degree of fibrosis.

4-Aminobenzoic Acid↗
PubMed1993

Carcinogenic potential of fluorescent UV tanning sources can be estimated using the CIE erythema action spectrum.

In legislation the CIE human erythema action spectrum is used to assess the risk of UV radiation appliances for household use. The most popular type of UV radiation source for private use is the low pressure 'UVA' radiation source, which mainly emits in the UVA area, but also has some emission in the UVB area. Recently reports have raised doubt whether the CIE erythema action spectrum is a good approximation for the carcinogenic risk. Therefore, it was investigated whether the carcinogenic potential of differing UV tanning sources, which mainly emit in the UVA area, could be assessed by using the CIE erythema spectrum. Two groups of lightly pigmented C3H/Tif mice were initially exposed to broad spectrum UV radiation with a high output of UVB (UVB emission 16.7%) during 84 days, in a daily dose of 4.67 Basic minimal erythema doses (Basic-MED). Subsequently, one group was exposed to Bellarium-S SA-1-12 (UVB emission 6.9%), the other to Philips TL 09R (UVB emission 2.2%), in a daily dose of 1 Basic-MED. The time to occurrence of seven tumour end-points was almost identical in the two groups, p > 0.4. To obtain further information on the relationship between the daily dose of common UV tanning sources measured in Basic-MED and tumour development, we combined the result of this experiment with the results of two others. There existed a negative correlation between the daily exposure dose measured in Basic-MED and the tumour induction time, p < or = 0.05. This inverse relationship was observed both when the UV tanning sources were administered with or without a prior exposure to broad spectrum UV irradiation. Our results indicate that the carcinogenic risk of UV tanning sources in the hairless C3H/Tif mouse can be estimated by the CIE erythema action spectrum.

Animals↗
PubMed1993

Vitronectin in mouse skin: immunohistochemical demonstration of its association with cutaneous amyloid.

Vitronectin is a multifunctional glycoprotein known to be associated with the dermal elastic fiber network in human adults, with various types of human amyloid and with apoptotic keratin bodies in human skin. It has also been shown to bind to human keratin intermediate filaments and to intranuclear material in vitro. To learn more of its function and mode of tissue deposition, vitronectin in mouse skin was studied. Vitronectin was purified from mouse plasma and a polyclonal anti-vitronectin antiserum was produced. This was used in an avidin-biotin-peroxidase complex technique and in an immunofluorescence technique on biopsy sections of dorsal skin from mice. Hairless lightly pigmented mice, known to develop dermal amyloid deposits at advanced ages, were used, making it possible to study vitronectin's association not only with elastic fibers but also with amyloid. Association of vitronectin with elastotic material was investigated in mice exposed to ultraviolet radiation. No vitronectin immunoreactivity could be demonstrated in association with elastin-stained material in skin specimens from any of the mice, whether exposed to ultraviolet radiation or not. In contrast, vitronectin was constantly found to be associated with dermal amyloid deposits. Moreover, mouse vitronectin was found to bind to mouse keratinocytes when studied by immunofluorescence staining of skin sections that had been pre-incubated with mouse plasma as sources of vitronectin. The results indicate that vitronectin is associated with amyloid and can bind to intracellular structures in epidermal keratinocytes in mice as in humans, and that mouse tissue may be used for the study of vitronectin's interactions with amyloid and with intracellular structures.

Amino Acid Sequence↗
PubMed1993

UV-induced alterations in skin and lymphocytes during a one-week holiday in the Canary Islands in May.

The effect of solar exposure during a one-week sunbathing vacation in May at 29 degrees N latitude was investigated in 22 volunteers. The following end-points were measured before and after the holiday: skin reflectance at 507 nm, transmission of radiation from 289 nm to 448 nm through the epidermis, epidermal thickness, minimal erythema dose (MED), total white cell, neutrophil, lymphocyte, and lymphocyte subpopulation counts in blood, spontaneous DNA synthesis, DNA strand breaks and sister-chromatid exchange in lymphocytes, and the UVC tolerance of lymphocytes. There was a statistically significant decrease in skin reflectance (p < 0.001) and epidermal transmission (p < 0.01) after the holiday, reflecting increased pigmentation and epidermal thickening. There was a statistically significant increase in epidermal thickness (p < 0.001), MED (p < 0.05), spontaneous DNA synthesis (p < 0.01) and DNA strand breaks in lymphocytes (p < 0.02) after the holiday. The other end-points were not significantly changed. We report that changes in skin pigmentation and epidermal thickness occur after one week of UV exposure. It was also observed that a one-week UV exposure increased both spontaneous DNA repair and the amount of DNA strand breaks in the lymphocytes of the volunteers, while no changes in T-cell subsets were detected.

Adult↗
PubMed1992

UVA tanning devices interact with solar-simulated UV radiation in skin tumor development in hairless mice.

The carcinogenic effect of three UVA tanning sources was studied in lightly pigmented hairless mice. The three tanning sources (Bellarium-S SA-1-12, Philips TL 09R and Philips TL 10R) have different emission spectra, and emit different amounts of UVB. Radiation from the tanning sources was administered for 20 min/day, 5 day/week in daily doses equivalent to those used in suntan salons. The radiation was given alone or after 12 weeks of exposure to solar-simulated UV radiation (SOLAR UV) (10 min/day, 4 day/week; daily dose, 19.5 kJ/m2 UVA and 3.9 kJ/m2 UVB). Irradiation with Bellarium-S SA-1-12 for 47 weeks and Philips TL 09R for 74 weeks induced skin tumours in 20/20 and 13/20 of the animals, respectively. When irradiation with Bellarium-S SA-1-12 and PHilips TL 09R was administered after 12 weeks of SOLAR-UV exposure, a strong enhancement of SOLAR-UV-induced photocarcinogenesis was observed (p < 0.001). Irradiation with Philips TL 10R was only slightly carcinogenic, and during 85 weeks of irradiation only one skin tumor appeared in a group of 20 mice. However, when irradiation with Philips TL 10R was administered after 12 weeks of exposure to SOLAR UV, an enhancement of SOLAR-UV-induced carcinogenesis was observed (p < 0.001). Our results suggest that the hazards of exposure to commercial tanning devices are increased when they are used after a period of natural sun exposure. Even tanning sources with a low carcinogenic potential are able to increase SOLAR-UV-induced carcinogenesis significantly.

Animals↗
PubMed1991

Sister-chromatid exchanges in cannabis smokers.

The genotoxicity of cannabis smoking was evaluated by means of the sister-chromatid exchange (SCE) test. The SCE test is considered to be a sensitive tool for the discovery of genotoxic agents in the environment. Twenty-two tobacco smokers and 22 persons smoking both tobacco and cannabis were compared. Our findings showed that smoking in itself enhanced the SCE level significantly (18.5%) compared to a group of non-smokers, but adding smoking of cannabis to tobacco smoking did not affect the SCE level further. Based on our observations cannabis smoking could not be considered genotoxic.

Adolescent↗
PubMed1991

Xeroderma pigmentosum lesions related to ultraviolet transmittance by clothes.

Xeroderma pigmentosum is associated with severe actinic degeneration of the skin. Our patient with xeroderma pigmentosum showed increasing actinic damage in some areas covered by clothes. We therefore performed a complete evaluation of the patient's exposure to ultraviolet radiation. This included transmission measurements of the patient's clothes, glasses, and car windows. The transmission of UVB (280 to 320 nm) by the clothes varied from none to 17.8%. The transmitted UVB radiation was proportional to the clinical manifestations of xeroderma pigmentosum. The patient's wardrobe was changed, and UVA-blocking film was applied to the windows of the car and house. A decline in manifestations was seen after 18 months of improved ultraviolet protection.

Adult↗
PubMed1991

Photocarcinogenesis in hairless mice induced by ultraviolet A tanning devices with or without subsequent solar-simulated ultraviolet irradiation.

The carcinogenic effect of 3 commercially available ultraviolet A (UVA) tanning sources was studied in lightly pigmented hairless mice. The tanning sources (Bellarium-S SA-1-12 and Philips TL 09R and TL 10R) have different emission spectra and emit different quantities of UVB. The tanning sources were administered either alone, or before irradiation with solar-simulated UV (solar UV). All 3 UVA tanning sources were able to induce skin tumors when administered in daily doses resembling those used in tanning salons (20 min/d, 5 d/week). Irradiation with Bellarium-S during 32 weeks induced skin tumors in all mice; a similar response was seen after 66 weeks of irradiation with Philips TL 09R. Irradiation with Philips TL 10R during 98 weeks induced tumors in 6 of 20 mice. Nine groups of 20 mice were pretreated 20 min/d, 5 d/week during 13 weeks with one of the UVA tanning sources. Three groups were irradiated with Bellarium-S, 3 groups with Philips TL 09R and 3 groups with Philips TL 10R in daily doses ranging from 0.2 to 1.8 minimum erythema doses (MED). The highest daily doses were equivalent to the doses received during one session in a commercial solarium. Subsequently all 9 groups were irradiated with 3.1 MED/d solar UV 10 min/d, 4 d/week until all mice had died. Time to first tumor was compared. All groups pretreated with Bellarium-S and Philips TL 09R showed an enhanced tumor development compared with a group irradiated with solar UV only. Pretreatment with Philips TL 10R did not enhance the carcinogenic effect of solar UV.

Animals↗
PubMed1990

Monitoring of genotoxic exposure of humans by the sister chromatid exchange test. Methodology and confounding factors.

During the last decades several in vitro assays for measurement of genotoxic exposure have been developed. Exposure of humans to genotoxic products in their workplaces and the environment may be evaluated by means of the sister chromatid exchange test (SCE), which visualize exchange of DNA material between sister chromatids of a chromosome. This thesis deals with the development of SCE methodology and screening of confounding factors to make the method useful in population monitoring of genotoxic exposure of chemicals in vivo. Human lymphocytes are cultured under standardized conditions. The cells are prepared for chromosome analysis by means of new-developed apparatuses treating 12 samples simultaneously. By this method the preparation is speeded up and breathing of glacial acetic acid is minimized. Slides are prepared and stained. The staining procedure includes irradiation of the slides with long wave UV light. The light source has been optimized with regard to simplicity and spectral distribution to fit the absorption spectrum of the dye bisbenzimid. The irradiation time and dose to produce distinct harlequin stained chromosomes has been found. Population screening demands analysis in microscope of a great number of chromosomes. The working time at microscope is long and improvement of ergonomics and automation to speed up the procedure was obtained by development of a special microscope which projects the picture of SCEs at table level. The scanning table was motorized. These changes gave excellent ergonomic proporties as fixed positions of the eyes and hands were avoided. The system is fast and flexible and may semiautomatically produce karyotypes. By pointing out SCEs the system automatically registers SCE number, cell coordinates, mitosis quality and perform statistics. The statistical model which best describe the distributions of SCE data has been analysed. This was a negative binomial distribution, which is close to the Poisson distribution. The transformation y = (S).5 + (S + 1).5 follows a normal distribution. Variances of the transformation of the sum of SCEs in 30 cells within subjects and between subjects have been calculated, and on that basis the demands to sample size have been calculated. To avoid to make false statements about a connection between an exposure and SCE a detailed knowledge of confounding factors is essential. Of endogenous factors gender, age, race, and heredity have been considered. Of these gender and age contribute to the variation in SCE. Very high SCE level has been found in healthy members of a family and such cases have to be excluded from exposure studies.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1989

Rapid recovery of Langerhans cell alloreactivity, without induction of autoreactivity, after in vivo ultraviolet A, but not ultraviolet B exposure of human skin.

For therapeutic medical, cosmetic, and recreational reasons, humans expose themselves to increasing amounts of UVA. However, little is known of the photobiologic events associated with cutaneous carcinogenesis and photoaging that occur as a result of UVA exposure. UVB exposure of human skin abrogates the function of epidermal CD1+DR+ Langerhans cells and induces the appearance of CD1-DR+ non-Langerhans cell APC. This non-Langerhans cell APC population activates autoreactive immunoregulatory T cells that lead to suppressor-effector T cell function. In this report we show that, similarly to UBV, UVA exposure abrogates the function of CD1+DR+ Langerhans cells. However, in contrast to UVB, there is rapid recovery of Langerhans cell antigen-presenting cell activity and that CD1-DR+ non-Langerhans cell APC failed to appear to a significant degree. In keeping with the lack of CD1-DR+ epidermal cells, UVA exposed epidermal cells harvested 3 days after exposure functioned similarly to normal epidermis in that they activated alloreactive T cells but not autoreactive T cells in the absence of added Ag. This was in contrast to UVB irradiated epidermal cells that potently activate autoreactive T cells and contain CD1-DR+ cells. Thus, although both UVA and UVB initially depletes and inactivates CD1+DR+ Langerhans cells, the subsequent APC function of epidermal cells exposed to UVA differ profoundly from that of cells exposed to UVB. UVA radiation is less carcinogenic than UVB; differences in host responses to UV tumors may be linked to the rapid recovery of Langerhans cell function and the lack of induction of CD1-DR+ non-Langerhans cell APC after UVA exposure.

Adult↗
PubMed1989

Tattoo removal by overtattooing with tannic acid.

Removal of tattoos was studied in the guinea pig. Professional tattoos were made, and two different solutions of tannic acid were injected intradermally into the tattoos four times. The macroscopic end result was formation of a slight fibrosis with little visible pigment. Histologic examination after treatment showed a moderate fibrosis with little visible pigment situated deeper in the dermis than in the untreated tattoo.

Animals↗
PubMed1989

A tuneable, narrow-band, high-intensity UV source.

More potent narrow-band UV sources need to be developed to determine the in vivo action spectra of long-term UV effects, such as photocarcinogenesis. This article describes the development of a potent, narrow-band UVB source, an Oriel solar simulator modified by the use of newly developed all-dielectric interference (ADI) filters. The sharp cut-off edges and high levels of transmission are unique features of these filters. Further, they can be produced as long-wave-pass or short-wave-pass filters with maximum transmittance at any given wavelength. The simulator is equipped with up to 4 ADI filters and potentially emits narrow UV bands. The filter combinations for narrow bands allow transmission of up to 80% of the incoming radiation. There was a homogeneous intensity area of 25 X 25 cm at a distance of 150 cm from the source in the centre of the irradiation field. The average intensity of UV available in narrow bands of UV (with a minimum half-band width of 11 nm) was 140 mW/m2. These values are sufficient to determine action spectra in groups of live animals (mice).

Equipment Design↗
PubMed1989

Narrow-band UV radiation and induction of dermal elastosis and skin cancer.

A narrow-band UV light source with emission peaks at 292, 300, 307, 317, and 336 nm was developed and used to irradiate whole cages of hairless mice. The purpose was to obtain experimental information on the action spectrum for photocarcinogenesis and dermal elastosis. Groups of 20 mice were irradiated with 500 J/m2 daily, 5 times per week during one year. The total dose was 130 kJ/m2. All mice irradiated with 292 nm and 300 nm developed squamous cell carcinomas. None in the other groups developed malignant skin tumors. Elastosis was estimated quantitatively. The elastic fibers covered 3% of a representative microscopic section of dermis in the control group. In the groups irradiated with peaks at 336 nm, 317 nm, 307 nm, 300 nm, and 292 nm the corresponding percentages were 6%, 13%, 28%, 32%, and 36%, respectively. The shorter the wavelengths the more pronounced was a subepidermal zone replacing the elastotic tissue to the deeper dermis. This zone stained corresponding to a content of glycosaminoglycans (GAG), sulphated GAG, hyaluronic acid, mature collagen, and new reticulin.

Animals↗
PubMed1988

No detectable increase in sister chromatid exchanges in lymphocytes from mycosis fungoides patients after topical treatment with nitrogen mustard.

We measured sister chromatid exchanges (SCEs) in lymphocytes of eight MF patients before, and 2 h, and 24 h after treatment with topical nitrogen mustard. The mean number of SCEs/cell (+/- SEM) were 8.15 (+/- 0.62), 8.34 (+0.55) and 8.26 (+/- 0.56), respectively. The 2 h and 24 h results do not differ significantly from pretreatment levels. Our results show that concentrations of nitrogen mustard used to control MF do not induce SCEs in peripheral blood lymphocytes.

Aged↗