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Biomedical subjects

N Bech-Thomsen

Publications and source records attributed to N Bech-Thomsen.

At least 19 recordsLinked to original sources
PubMed2006

Effect of a new silver dressing on chronic venous leg ulcers with signs of critical colonisation.

OBJECTIVE: To investigate the clinical performance and safety of a new silver-containing wound-contact layer, Physiotulle -Ag (Coloplast), in the treatment of chronic venous leg ulcers with delayed healing and signs of critical colonisation. METHOD: This was an open prospective non-comparative multicentre clinical study. Patients were treated for four weeks with Physiotulle -Ag, which was covered by Alione Hydrocapillary Dressing (Coloplast). RESULTS: Thirty patients were recruited into the study. One ulcer healed after three weeks of treatment. The mean relative ulcer area reduced by 55% after four weeks. Over the study period the mean amount of healthy granulation tissue increased from 26% to 62%, and the mean amount of fibrin decreased from 63% to 32%. The ratio of malodorous wounds was 50% at inclusion, 20% after one week and 3% after four weeks. The dressing was considered easy or very easy to apply in 100% and easy to remove in 89% of dressing evaluations. The dressing combination showed good exudate-management properties. Incidence and severity of maceration, erythema and eczema decreased during the study and no device-related adverse events were recorded. CONCLUSION: Physiotulle -Ag is safe and easy to use in chronic venous leg ulcers in which healing is delayed and with signs of critical colonisation.

Aged↗
PubMed2000

Optimized UVB treatment of psoriasis: a controlled, left-right comparison trial.

In a randomized, controlled, left-right comparison study, 20 patients with chronic plaque psoriasis were treated with UVB. One side of the body received UVB in a conventional regimen with fixed dose increments, the other side was given UVB doses according to measurements of skin pigmentation. Skin pigmentation was quantified by the skin reflectance technique. The relationship between skin pigmentation and sensitivity to UV radiation was used to optimize and individualize the initial UVB exposure dose. Clinical outcome, initial, final and cumulative UVB doses, time to 50% reduction in PASI score, and side-effects were compared. The consequence of the optimization of the UVB doses with a skin reflectance meter was that the initial UVB dose was significantly higher than in the conventional UVB regimen. PASI scoring demonstrated a more rapid improvement during the first 2 weeks of treatment on the half body receiving the optimized treatment compared to the other side (P < 0.05). This new technique offers the same therapeutical advantages and security as a dose regimen guided by minimal erythema dose testing. However, measurement of skin pigmentation by skin reflectance is a quick method which can be operated easily by nurses.

Adult↗
PubMed1998

Impact of epidermal thickness on purpura from the pulsed dye laser.

BACKGROUND AND OBJECTIVE: To clarify whether epidermal thickness is of importance to the purpuric reaction from treatment with the pulsed dye laser (PDL). STUDY DESIGN/MATERIALS AND METHODS: Fifteen fairly pigmented volunteers were laser treated in two test regions of varying epidermal thicknesses: normal buttock skin and ultraviolet B (UVB)-exposed buttock skin. Laser treatments were performed with the flashlamp-pumped PDL (585 nm). Fluences ranged from 3-6.5 J/cm2, spot size was 7 mm, and each volunteer received at least six fluences in each treatment region. Assessment of the response was based on clinical evaluation (threshold dose to purpura 10 minutes and 1 day after treatment) and skin reflectance-evaluated redness (1 and 6 days, 2 and 6 weeks after treatment). RESULTS: The total epidermal thickness differed between the unexposed buttock skin (median, 72.7 microm) and the UVB-exposed buttock skin (87.2 microm) (P < 0.01). There was no correlation between the epidermal thickness and the threshold dose to induce purpura 10 minutes and 1 day after laser exposure. Skin reflectance revealed no correlation between the epidermal thickness and the skin reflectance evaluated redness on 1, 6 days, and 2 weeks postoperatively. A dose-response relation was seen within the two test regions; 6 weeks after laser exposure, there was no remaining laser-induced skin redness. CONCLUSION: The epidermal thickness is unimportant to the purpuric reaction after PDL treatment.

Adult↗
PubMed1998

Ofuji's papuloerythroderma: a study of 17 cases.

In this retrospective study the clinical, laboratory and histological features, treatment methods and disease course in 17 patients with papuloerythroderma (PE) are reviewed. The median age at diagnosis was 72 years and the female/male ratio was 1:4:7. The most common abnormal laboratory findings were eosinophilia and an elevated serum IgE level. Psoralen photochemotherapy (PUVA) and oral prednisolone 10-20 mg daily given in combination or alone were very efficient treatments, while UVB phototherapy in combination with topical steroids was also successful. However, potent topical corticosteroids alone or in combination with oral antihistamines were not effective. The patients were observed for a median of 19 months from diagnosis, three being followed for more than 5 years. Five of the patients relapsed, but only one had multiple relapses, two developed cutaneous T-cell lymphoma (CTCL) and two others had histological features suggestive of that disorder. Six of the patients died, cardiovascular disease being the most common cause. PE is a distinct clinical entity with a polymorphous aetiology which frequently includes an association with CTCL or visceral malignancy. PUVA, oral corticosteroids and UVB in combination with topical corticosteroids appear to be effective therapeutic modalities.

Aged↗
PubMed1998

Side effects from the pulsed dye laser: the importance of skin pigmentation and skin redness.

The pulsed dye laser is the treatment of choice for port-wine stains. In this study we evaluate the importance of preoperative skin pigmentation and skin redness for the development of side effects from one treatment with the pulsed dye laser. A risk assessment is performed and skin reflectance measurement objectifies postoperative pigmentary changes. Fourteen human volunteers (skin types I to V) were laser-treated on the inside of the proximal brachium. Photographic documentation was used for blinded, clinical evaluation of side effects 3 and 6 months postoperatively. Skin was artificially reddened using topical application of 10% nicotinic acid cream. The development of pigmentary alterations and texture changes depended on the preoperative pigmentation and redness degrees. The risk of inducing clinically visible pigmentary alterations and texture changes increased with higher preoperative skin pigmentation and redness degrees, and with the application of increasing laser doses. Pigmentary alterations were induced at a lower fluence level than texture changes. The risk of side effects was higher 3 months postoperatively than 6 months postoperatively, substantiating a gradual disappearance of side effects. Skin reflectance measurements documented postoperative hyperpigmentation that faded partially from 3 to 6 months postoperatively. This is the first human experimental model for port-wine stains which provides quantitative data on the relationship between preoperative skin colours and postoperative clinically disturbing side effects.

Administration, Cutaneous↗
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↗
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

Photodynamic therapy with topical delta-aminolevulinic acid delays UV photocarcinogenesis in hairless mice.

Photodynamic therapy (PDT) with topical application of delta-aminolevulinic acid (ALA) followed by irradiation with visible light (ALA-PDT) is a relatively new and promising experimental treatment of superficial premalignant and malignant skin neoplasms. The purpose of this study was to determine whether ALA-PDT can prevent photocarcinogenesis in hairless mice exposed to solar UV. A total of 140 mice was divided into seven groups of 20 mice each. Group 1: solar-UV exposure. Group 2: solar UV and a cream base+visible light once a week. Group 3: solar UV and ALA-PDT once a week. Group 4: solar UV and ALA-PDT once every second week. Group 5: solar UV and ALA-PDT every fourth week. Group 6: ALA-PDT once a week. Group 7: no treatment. The time to first and to second tumor > or = 1 mm was registered. Predefined endpoints, such as one tumor > or = 4 mm or an area of small confluent tumors on the back of the mice were criteria for withdrawal from the experiment. The time to first and to second tumor was significantly longer in the ALA-PDT-treated mice than in mice only exposed to solar UV and solar-UV/cream base-visible light (P < 0.005). However, we observed an increased death and accident rate in the ALA-PDT-treated groups compared to the groups not treated with ALA-PDT (chi-square test, P = 0.0250). Significantly more ALA-PDT-treated mice were withdrawn because of a tumor > or = 4 mm (P = 0.0005). The UV unexposed mice developed no tumors. Repetitive treatments with ALA-PDT delay photoinduced carcinogenesis in mice.

Administration, Topical↗
PubMed1996

Skin reflectance-guided laser selections for treatment of decorative tattoos.

BACKGROUND AND DESIGN: A fundamental idea of laser treatment of tattoos is that the wavelength must be well absorbed by the tattoo color. In this study, absorption by different tattoo colors was therefore measured in vivo by skin reflectance to establish optimal laser wavelengths for different tattoo colors. Spectral reflectance by tattooed skin and by normal, uninvolved skin was measured in 10-nm steps in a wavelength range from 300 to 800 nm on eight human volunteers with a total of 13 tattoos, which consisted of 14 different tattoo colors. Wavelength ranges for maximal absorption were established. RESULTS: We found that tattoos absorbed maximally in the following ranges: red tattoos, from 505 to 560 nm (green spectrum); green tattoos, from 630 to 730 nm (red spectrum); and a blue-green tattoo, in two ranges from 400 to 450 nm and from 505 to 560 nm (blue-purple and green spectrums, respectively). Yellow tattoos absorbed maximally from 450 to 510 nm (blue-green spectrum), purple tattoos-absorbed maximally from 550 to 640 nm (green-yellow-orange-red spectrum), blue tattoos absorbed maximally from 620 to 730 nm (red spectrum), and orange tattoos absorbed maximally from 500 to 525 nm (green spectrum). Black and gray absorbed broadly in the visible spectrum, but these colors were most effective from 600 to 800 nm. Optimal and suboptimal laser wavelengths are proposed. CONCLUSIONS: We recommend that wavelength ranges should be established for maximal tattoo absorption before laser treatment of decorative tattoos to select the most optimal laser wavelength present.

Adult↗
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

Solar pruritus.

A case of solar pruritus is reported. Severe pruritus of the back, shoulders and upper lateral aspects of the arms, without any eruption, developed in a 28-year-old outdoor worker during 4 to 6 weeks of intensive solar exposure. The pruritus was intense and described as a burning sensation deep in the skin. Only a few excoriations and slight xerosis were found. Solar pruritus or brachioradial pruritus is a condition primarily seen in Caucasian people living in the tropics or subtropics. Previously the disease has only been reported once outside these areas.

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↗