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A great number of journeys to sunny destinations are sold to the Danish population every year. We suspect that this travel considerably increases personal annual ultraviolet-radiation (UVR) exposure doses. This is important because such exposure is the main cause of skin cancer, and studies have shown a correlation between intermittent solar UVR exposure and malignant melanoma.To prospectively monitor the behaviour of a group of sun seekers during a winter sun holiday and to study the impact of behaviour on personal UVR exposure doses.In this observational study 25 Danish sun seekers were closely monitored by on-site investigators for 6 days during a winter sun holiday in the Canary Islands, thus avoiding the possible recall bias of retrospective studies with questionnaires. The volunteers recorded their location, clothing and sunscreen use in diaries, and their UVR doses were measured by personal UVR dosimeters worn on the wrist. This resulted in 3450 half-hour registrations during 150 participation days.On average, each volunteer received a total UVR dose of 57 standard erythema doses over 6 days, which is 43% of the annual UVR dose of a Danish indoor worker. Their exposed body area, sunscreen use and percentage of body with sunscreen application were positively correlated with their personal UVR doses, and there was also a strong relationship between location and UVR doses received.The behaviour of the volunteers had a major impact on their personal UVR doses. Our results emphasize the importance of changing the behaviour of sun seekers with protanning attitudes to reduce their personal annual UVR exposure doses, and possibly their risk of skin cancer.

From 1991 to 1992, 28 patients with chronic plaque psoriasis were treated with a new UVB treatment regimen guided by skin reflectance measurements. The severity of the disease, the efficacy of the treatment, the number of side-effects and the cumulative UVB dose were recorded. These data were compared in an open study with the data obtained from 18 patients with chronic plaque psoriasis, who were treated from 1988 to 1991 at our department with a UVB treatment regimen with regular dose increments. There was no difference in the severity of the disease at the beginning of the therapy or in the healing score between the two groups. The cumulative UV exposure was lower with the new treatment regimen (30 basic minimal erythema doses) compared with the old regimen (89 basic minimal erythema doses). The skin reflectance-guided UVB therapy achieved a response earlier (5 weeks) than the regimen with stepwise dose increments (9 weeks). This study indicates that skin reflectance-guided UVB phototherapy may enable t...

Sunscreens absorb ultraviolet B (UVB) and it is a major concern that sunscreen use may lead to vitamin D deficiency.To investigate the relation between the amount of sunscreen applied and the vitamin D serum level in humans after UVB exposure under controlled conditions.Thirty-seven healthy volunteers with fair skin types were randomized to receive an inorganic sunscreen with sun protection factor (SPF) 8 of 0 mg cm(-2) , 0.5 mg cm(-2) , 1 mg cm(-2) , 1.5 mg cm(-2) , or 2 mg cm(-2) thickness on the upper body, approximately 25% of the body area. Participants were irradiated with a fixed UVB dose of 3 standard erythema doses 20 min after sunscreen application. This procedure was repeated four times with a 2- to 3-day interval. Blood samples were drawn before the first irradiation and 3 days after the last to determine the serum vitamin D level expressed as 25-hydroxyvitamin D(3) [25(OH)D].The vitamin D serum level increased in an exponential manner with decreasing thickness of sunscreen layer in response to UVB exposure. For all thicknesses of sunscreen, the level of 25(OH)D increased significantly after irradiation (P0.05), except for the group treated with 2 mg cm(-2) , in which the increase in 25(OH)D was not statistically significant (P=0.16).Vitamin D production increases exponentially when thinner sunscreen layers than recommended are applied (2 mg cm(-2) ). When the amount of sunscreen and SPF advised by the World Health Organization are used, vitamin D production may be abolished. Re-evaluation of sun-protection strategies could be warranted.

Photodynamic therapy (PDT) is an attractive therapy for nonmelanoma skin cancers and actinic keratoses (AKs). Daylight-mediated PDT is a simple and tolerable treatment procedure for PDT. Methyl aminolaevulinate (MAL)-PDT is approved for the treatment of thin or nonhyperkeratotic AKs on the face and scalp. However, thick AK lesions are often treated as well when present in the field-cancerized treatment area.In a randomized multicentre study to evaluate efficacy of daylight-mediated PDT for different severity grades of AKs.One hundred and forty-five patients with a total of 2768 AKs (severity grades I-III) of the face and scalp were randomized to either 1½ or 2½ h exposure groups. After application of a sunscreen (sun protection factor 20) and gentle lesion preparation, MAL was applied to the entire treatment area. Patients left the clinic immediately after application and exposed themselves to daylight according to randomization. Daylight exposure was monitored with a wrist-borne dosimeter.No difference in lesion response was found between the 1½ and 2½ h exposure group. The mean lesion response rate was significantly higher in grade I lesions (75·9%) than in grade II (61·2%) and grade III (49·1%) lesions (P0·0001). Most grade II (86%) and III AKs (94%) were in complete response or reduced to a lower lesion grade at follow-up. Large variations in response rate of grade II and III AKs were found between centres. No association was found between response rate and light dose in patients who received an effective light dose of3·5 J cm(-2).Daylight-mediated PDT of moderate to thick AKs was less effective than daylight-mediated PDT of thin AKs especially in some centres. However, nearly all thicker lesions (grades II and III) were reduced to a lower lesion grade at 3 months after a single treatment of daylight-mediated PDT.

Field cancerization is a term that describes the presence of genetic abnormalities in a tissue chronically exposed to a carcinogen. These abnormalities are responsible for the presence of multilocular clinical and sub-clinical cancerous lesions that explains the increased risks of multiple cancers in this area. With respect to the skin, this term is used to define the presence of multiple non-melanoma skin cancer, its precursors, actinic keratoses and dysplastic keratinocytes in sun exposed areas. The multiplicity of the lesions and the extent of the area influence the treatment decision. Providing at least equivalent efficacy and tolerability, field directed therapies are therefore often more worthwhile than lesion targeted approaches. Photodynamic therapy (PDT) with its selective sensitization and destruction of diseased tissue is one ideal form of therapy for this indication. In the following paper the use of PDT for the treatment of field cancerized skin is reviewed and recommendations are given for its use.

Previous studies on ultraviolet radiation (UVR) exposure before and after a diagnosis of cutaneous malignant melanoma (CMM) have been based primarily on questionnaires. Objective measures are needed.To assess changes in UVR exposure in patients with CMM using objective surrogate parameters in a descriptive study.Ten patients recently diagnosed with CMM during the 5 months (autumn and winter) preceding study start in February 2009; 21 patients diagnosed from 12 months to 6 years before study start; and 15 controls, who matched the recently diagnosed patients on age, sex, residential area, constitutive skin type and occupation completed the investigations. UVR exposure before and after diagnosis of CMM was assessed using measures of serum 25-hydro vitamin D [25(OH)D], skin pigmentation and by interviews. Winter 25(OH)D was used as a surrogate parameter of UVR exposure the previous summer - the summer before CMM diagnosis in recently diagnosed patients.Winter 25(OH)D was significantly higher among recently diagnosed patients compared with controls (P = 0·02, R² = 0·60) and patients diagnosed up to 6 years earlier (P = 0·01). The increase in 25(OH)D during the summer after diagnosis was significantly lower for recently diagnosed patients than for controls (P = 0·005, R² = 0·51) and patients diagnosed up to 6 years earlier (P = 0·008). No difference was found in summer 25(OH)D between the groups.Our findings suggest that patients with CMM had a higher UVR exposure the summer before diagnosis than did controls and patients diagnosed up to 6 years earlier, and that after diagnosis UVR exposure fell to the level of controls in patients with CMM.

Mismatches between skin pigmentation and modern lifestyle continue to challenge our naked skin. One of our responses to these challenges is the development and use of sunscreens. The management of sunscreens has to balance their protective effect against erythema, photocarcinogenesis and photoageing owing to the potential toxicity of the ultraviolet (UV) filters for humans and the environment. The protection against UV radiation offered by sunscreens was recently standardized in the European Union (EU) based on international harmonization of measurement techniques. Four different categories of sun protection have been implemented along with recommendations on how to use sunscreen products in order to obtain the labelled protection. The UV filters in sunscreens have long been authorized for use by the EU authority on the basis of data from studies on acute toxicity, subchronic and chronic toxicity, reproductive toxicity, genotoxicity, photogenotoxicity, carcinogenicity, irritation, sensitization, phototoxicity and photosensitization as well as on environmental aspects. New challenges with respect to the safety of UV filters have arisen from the banning of animal experiments for the development of cosmetics. Future debates on sunscreens are likely to focus on nanoparticles and environmental issues, along with motivation campaigns to persuade consumers to protect their skin. However, more efficient sunscreen use will also continue to raise questions on the benefit in preventing vitamin D synthesis in the skin induced by sunlight.

Actinic keratoses (AKs) are common dysplastic skin lesions that may differentiate into invasive squamous cell carcinomas. Although a superior cosmetic outcome of photodynamic therapy (PDT) is advantageous compared with equally effective treatments such as cryotherapy and curettage, the inconvenience of clinic attendance and discomfort during therapy are significant drawbacks. Daylight-mediated PDT could potentially reduce these and may serve as an alternative to conventional PDT.To compare the efficacy of methyl aminolaevulinate (MAL)-PDT with 1½ vs. 2½ h of daylight exposure in a randomized multicentre study.One hundred and twenty patients with a total of 1572 thin AKs of the face and scalp were randomized to either 1½- or 2½-h exposure groups. After gentle lesion preparation and application of a sunscreen of sun protection factor 20, MAL was applied to the entire treatment area. Immediately after, patients left the clinic and exposed themselves to daylight according to the randomization. Daylight exposure was monitored with a wristwatch dosimeter and patients scored their pain sensation during treatment.The mean lesion response rate at 3 months was 77% in the 1½-h group and 75% in the 2½-h group (P = 0·57). The mean duration of daylight exposure was 131 and 187 min in the two groups. The mean overall effective light dose was 9·4 J cm(-2) (range 0·2-28·3). Response rate was not associated with effective daylight dose, exposure duration, treatment centre, time of day or time of year during which the treatment was performed. Treatment was well tolerated, with a mean ± SD maximal pain score of 1·3 ± 1·5.Daylight-mediated MAL-PDT is an effective, convenient and nearly pain-free treatment for patients with multiple thin AKs. Daylight-mediated PDT procedures were easily performed and 2 h of daylight exposure resulted in uniformly high response rates when conducted in the period from June to October in Nordic countries.

Inflammatory acne vulgaris is a very common condition, particularly in adolescents and young adults, and new effective and well-tolerated treatments are needed.To evaluate the efficacy and tolerability of methyl aminolaevulinate-based photodynamic therapy (MAL-PDT) in patients with moderate to severe facial acne vulgaris in a randomized, controlled and investigator-blinded trial.Twenty-one patients were assigned to the treatment group and 15 patients to the control group. The treatment group received two MAL-PDT treatments, 2 weeks apart. Both groups were evaluated 4, 8 and 12 weeks after treatment. Efficacy evaluation included changes from baseline in numbers of noninflammatory and inflammatory lesions, changes from baseline in global acne severity grade and clinical assessments of clinical improvement by patient and evaluating dermatologist. Pain scores during treatment and local adverse effects were also evaluated.Twelve weeks after treatment the treatment group showed a 68% reduction from baseline in inflammatory lesions vs. no change in the control group (P=0.0023). We found no reduction in number of noninflammatory lesions after treatment. All patients experienced moderate to severe pain during treatment and developed severe erythema, pustular eruptions and epithelial exfoliation. Seven patients did not receive the second treatment due to adverse effects.MAL-PDT proved to be an efficient treatment for inflammatory acne. The treatment was associated with severe pain during treatment and severe adverse effects after treatments. Efforts must be made to optimize the treatment regimen and to avoid adverse effects.

Quantification of quality of life (QoL) related to disease severity is important in patients with atopic eczema (AE), because the assessment provides additional information to the traditional objective clinical scoring systems.To measure health-related QoL (HRQoL) in patients with AE; to analyse discriminant, divergent and convergent validity by examining the association between various QoL methods; and to examine the association between disease severity assessed by an objective Severity Scoring of Atopic Dermatitis (SCORAD) and QoL.HRQoL was assessed at two visits at a 6-monthly interval in 101 patients with AE and 30 controls with one dermatology-specific questionnaire [Dermatology Life Quality Index (DLQI) or Children's DLQI (CDLQI)], one generic instrument (SF-36) and three visual analogue scales (VASs) of severity and pruritus. Objective SCORAD was used to measure disease severity.Patients with AE had significantly lower QoL than healthy controls and the general population. DLQI /CDLQI, pruritus, and patient and investigator overall assessment of eczema severity were significantly (P0.0001) and positively correlated with SCORAD, while the generic questionnaire showed only poor correlation. A gender difference was found for the mental component score of SF-36 (P = 0.019).AE has an impact on HRQoL. Patients' mental health, social functioning and role emotional functioning seem to be more affected than physical functioning. A simple VAS score of patients' assessment of disease severity showed the highest and most significant correlations with most of the HRQoL methods used. There is evidence to support the ability of patients with AE to make an accurate determination of their disease severity and QoL.

Personal annual ultraviolet (UV) radiation data based on daily records are needed to develop protective strategies.To compare UV radiation exposure patterns in the winter half-year (October-March) and the summer half-year (April-September) for Danish indoor workers.Nineteen indoor workers (age range 17-56 years) wore personal UV dosimeters, measuring time-stamped UV doses continuously during a year. The corresponding sun exposure behaviour was recorded in diaries. Similar data were collected for 28 volunteers during sun holidays in the winter half-year. The relationship between UV dose and sun exposure behaviour was analysed.The ambient UV dose during the winter in Denmark (at 56 degrees N) was 394 standard erythema doses (SED) or 10.5% of the annual ambient UV dose. In winter compared with summer the subjects had: (i) a lower percentage of ambient UV radiation, 0.82% vs. 3.4%; (ii) a lower solar UV dose in Denmark, 3.1 SED (range 0.2-52) vs. 133 SED (range 69-363); (iii) less time outdoors per day with positive dosimeter measurements, 10 min vs. 2 h; and (iv) no exposure (0 SED) per day on 77% vs. 19% of the days. Sun holidays outside Denmark in winter gave a median 4.3 SED per day (range 0.6-7.6) and 26 SED (range 3-71) per trip.In the winter half-year indoor workers received a negligible UV dose from solar exposure in Denmark and needed no UV precautions. No UV precautions are needed from November to February during holidays to latitudes above 45 degrees N, while precautions are needed the whole year around at lower latitudes.

Sunburn cell (SBC) formation in the epidermis is a characteristic consequence of ultraviolet radiation (UVR) exposure at doses around or above the minimum erythema dose. SBC have been identified morphologically and biologically as keratinocytes undergoing apoptosis. There is evidence that SBC formation is a protective mechanism to eliminate cells at risk of malignant transformation. The level of DNA photodamage is a major determinant of SBC induction by a process controlled by the tumor suppressor gene p53. However, extra-nuclear events also contribute to SBC formation, such as the activation of death receptors including CD95/Fas. UVR triggers death receptors either by direct activation of these surface molecules or by inducing the release of their ligands such as CD95 ligand or tumor necrosis factor. Oxidative stress also appears to be involved, probably via mitochondrial pathways, resulting in the release of cytochrome C. Pathways which modify SBC formation are now extensively studied given the importance of apoptosis in eliminating irreparably damaged cells. A greater understanding of the mechanisms that induce and prevent UVR-induced apoptosis will contribute to our understanding of mechanisms relevant in genomic integrity.

There is no consensus on the methodology for describing the mechanical properties of human skin in vivo. Current descriptions are generally method dependent.The mechanical properties of palmar skin of the hypothenar as well as dorsal and ventral forearm skin were studied in 17 healthy volunteers. Two methods were used: ballistometry [Dia-stron Torsional Ballistometer (Diastron Ltd., Andover, UK)] and suction cup [The Dermaflex machine (Cortex Technology, Hadsund, Denmark)].A moderate degree of correlation was found between the methods (rs=0.315-0.540), while internal correlation between different measures obtained with one method was higher (rs=0.375-0.967). The suction cup method parameters (distensibility and elasticity) correlated significantly with the ballistometry parameters (indentation, alpha, area and coefficient of restitution), while the hysteresis did not correlate to ballistometry parameters. The coefficient of variation of both methods (CV=0.02-0.35) was within the range obtained with other non-invasive methods, e.g., TEWL. Regional differences were identified with both methods, while only the suction cup method identified age-related changes.The results suggest that while both methods may be useful, they describe related but not identical aspects of skin mechanics. The differences in measuring principle suggest that the suction cup method predominantly measures elasticity, while the ballistometer predominantly appears to measure stiffness. Hysteresis may be a unique measure of skin viscosity. Additional studies, however, are needed to specify the clinical significance of the various measures of skin mechanics.

The purpose of this study was to investigate the reliability of measuring solar ultraviolet radiation (UVR) doses with personal UV dosimeters worn on the wrist. Individual solar UVR exposure was measured over one day under standardised conditions (One-day Beach Study), and over an extended period of time with varying UV exposure and activities (Holiday Study). Dosimeters of a UV-sensitive spore-film filter type (VioSpor) were placed on the right wrist and on the top of head of the test subjects. The wrist was chosen as being a practical position for personal dosimetry and the head position as an internal control for maximal personal UV doses. The One-day Beach Study took place in the vicinity of Copenhagen in June 1998 over 5 h and included 11 subjects. The Holiday Study included 9 subjects during a period with a mean of 14 days in Scandinavia and Europe from June to September 1998. The head position received the highest UV dose in all subjects in both studies. In both studies, despite considerable individual variation, the mean wrist dose was the same (50%) of that received on the head, although the wrist dose correlated significantly with head dose (P0.01) only in the Holiday Study. We conclude that the wrist position is a practical and convenient body site for personal dosimetry, yielding reliable results in group exposure studies.

The purpose of this pilot study was to determine if photodynamic therapy with topical application of 5-aminolaevulinic acid followed by irradiation with incoherent filtered and unfiltered light (ALA-PDT) is an effective therapy for recalcitrant hand and foot warts. In 30 patients with recalcitrant warts, 49 regions with a total of 250 warts were randomized to one of the following five treatments: (i) ALA-PDT with white light applied three times within 10 days (W3); (ii) ALA-PDT with white light applied once (W1); (iii) ALA-PDT with red light applied three times within 10 days (R3); (iv) ALA-PDT with blue light applied three times within 10 days (B3), and (v) cryotherapy applied up to four times within 2 months (CRYO). The ALA-PDT treatment modality was repeated in case of partially responding warts. Significantly more warts were completely healed after W3 and W1 than after R3, B3 and CRYO (P0.01): 73% of the warts treated with W3 were completely healed, 71% after W1, 42% after R3, 23% after B3 and 20% after CRYO. No scars were observed in the ALA-PDT treated areas and patients treated for foot warts were all able to walk after the treatment. No recurrences in completely responding ALA-PDT treated warts were observed after 12 months of follow-up. In conclusion, photodynamic therapy with topical 5-aminolaevulinic acid followed by irradiation with white light is a promising treatment for recalcitrant hand and foot warts.

To determine the evidence base for routine therapeutic decisions in dermatologic out-patients.A retrospective review of a random sample of primary therapy and literature.University hospital, dermatologic out-patient clinic in CopenhagenA random sample of the case notes from 115 out-patients.The evidence base of therapy prescribed when the diagnosis was ascertained was studied in literature searches in MEDLINE and EMBASE. Evidence was structured into primary evidence consisting of randomized controlled trials, and secondary evidence consisting of follow-up studies or the application of trial results between diseases with pathogenic or clinical similarities, e.g. atopic and seborrheic dermatitis.Randomized controlled trials could be found describing 38% (95% confidence interval: 30-47) of all treatments. Secondary evidence was found for 33% (24-41), while no evidence was found for 23% (16-31) of the given treatments.Approximately three-quarters of dermatologic out-patient therapy is based on scientific evidence ranging from randomized controlled trials to logical deduction from analogous clinical situations. The proportion of evidence-based medicine in dermatologic therapy therefore appears to be comparable with that of internal medicine and may thus be above expectations.

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.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.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).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.

Three patients with cheilitis were successfully treated by photodynamic therapy using the topical application of 5-aminolevulinic acid (ALA), followed by irradiation with incoherent visible light. The three patients had had, for several years, disabling lesions on the lower lip, and histopathological examination showed dysplastic lesions without signs of carcinoma. Conventional treatments were ineffective. During photodynamic therapy, all patients reported a burning sensation when irradiated at the ALA treated area, diminishing immediately after removal of the light source, and vanishing within 4 days after treatment. Superficial peeling began 4 days after treatment, and lasted some months. Follow-up, after 6 and 12 months, did not reveal any sign of recurrence.

Port wine stains are commonly located on UV-exposed skin areas. We therefore examined the long-term interaction between UV radiation and copper vapor laser light (578 nm, yellow light) and whether the thermal influence from laser light had a carcinogenic potential itself.The study was conducted in lightly pigmented hairless hr/hr C3H/Tif mice and included 8 groups of 17-20 mice. Intensities of 0.5, 1.0, and 1.4 W were used, corresponding to calibrated Hexascan fluences of 15.9, 31.8, and 44.6 J/cm2. Beam diameter was 1 mm and pulse duration 250 msec. UV irradiation of the mice was performed 4 days weekly and started the day after laser treatment. The UV simulated solar ultraviolet radiation can from one Phillips TL 12 and five Bellarium-S SA-1-12 tubes. The daily dose was 1.3 J/cm2, equivalent to 2.1 B-MED.No tumors appeared in groups receiving laser light only. The time to first (P0.01), second (P0.01), and third (P0.02) tumor was significantly delayed in the group treated with 1.4 W before UV irradiation (P0.01) compared with those receiving UV radiation only. No significant differences could be demonstrated for the groups treated with 0.5 and 1.0 W.One laser treatment with the copper vapor laser did not accelerate UV-induced photocarcinogenesis, and the laser exposure did not have a malignant potential itself.

To explore the influence of sex on sister chromatid exchange (SCE) level, a pair of chimeric twins was examined for differences in SCE frequency between the XX and XY cells present in each individual. By this method, the influence of possible differences in environmental exposure was eliminated. SCE levels were varied by growing the cells in media containing 0, 1.3 × 10–7, or 6.5 × 10–7 M melphalan. XX cells showed a higher SCE count than XY cells. This difference increased with increasing SCE level and ranged from 5.4% to 7.8% (P = 0.0003) of the SCE counts. Only about 2% of the difference could be explained by the higher amount of DNA present in the XX cells than in the XY cells. In this case XX cells seemed to be more sensitive to SCE-inducing agents than XY cells.

Tritiated 8-methoxypsoralen was given perorally to rats in amounts corresponding to therapeutic human doses. The rats were exposed to UVA light or kept in darkness. None of the fractions (apart from 3H2O from the lens) examined changed their level of radioactivity under the influence of UVA light. Time-radioactivity curves were recorded for the skin, lens, residual eye, and the liver. Four fractions were measured: 3H2O, soluble pool, DNA-RNA, and protein. Tritiated water appeared already 1 h after ingestion, and attained maximum value 9-24 h after ingestion, indicating the efficiency with which the liver degrades 8-MOP. 3H-8-MOP and metabolites could be detected in the soluble pool in maximum amounts 2-3 h after the administration. Pretreatment with trypsin increased the concentration of 3H-8-MOP and metabolites; the origin of this extra radioactivity was the protein fraction. The 3H-8-MOP binding to DNA or RNA was studied by pretreatments of the homogenates with DNase or RNase followed by measurement of radioactivity in the TCA extracts. This indicated that no measurable amount of 3H-8-MOP had been bound to DNA or RNA. We conclude that 8-MOP administered to rats in amounts corresponding to human therapeutic doses does not bind to DNA or RNA in measurable amounts either after UV-light or in darkness. The experiments have shown proteins to be the main binding site in rat organs.

The acute effect of 8-methoxypsoralen (8-MOP) and 8-MOP + long wave ultraviolet light (UVA) on sister chromatid exchange (SCE) has been examined in an in vitro experiment. The SCE count was significantly increased by 8-MOP without light, but the effect was substantially greater (50%) by 8-MOP + UVA. In addition, mitoses with banded staining of the chromosomes were seen after 8-MOP and UVA. These changes were dose dependent, and they might be responsible for the reduced cell turnover in psoriasis plaque after PUVA.

Chromosome analysis of lymphocytes from the peripheral blood of 20 patients with sarcoidosis and 10 healthy controls showed a significantly greater number of hypomodal cells among the patients. Two patients receiving systemic treatment with glucocorticoids had many chromosomal aberrations.

Sister chromatid exchanges (SCE) and sister chromatid exchange points (SCE-points) were counted in lymphocytes in peripheral blood drawn from hospital personnel exposed to anaesthetics as well as from persons not exposed. A total of 38 healthy persons were investigated, representing female nurse anaesthetists, male physicians practising anaesthesia, female nurses from the intensive care unit, and female secretaries. The mean SCE number per cell for each person was used as the variable, and the Mann-Whitney U-test was applied to test for differences between groups. The group of secretaries seemed to differ from the other three groups, which appeared identical (P