[en] We used PUVA therapu in a patient with crisis-type adult T-cell leukaemia/lumphoma and generalized cutaneous leukaemic cell infiltration. PUVA proved very effective in reducing leukaemic cells and in clearing the eruption. To understand the way in which PUVA produced a reduction in the number of leukaemic cells, we examined peripheral blood cells by light and electron microscopy. Light microscopy was of little help, but electron microscopy revealed that PUVA induced apoptosis-like changes in circulating leukaemic cells. This suggests that apoptosis-like changes in leukaemic cells might be the reason for the success of this treatment. (Author)

[en] Ultraviolet (UV) irradiation of trans-urocanic acid (UCA), a major UV absorbing component of the epidermis, leads to the formation of cis-UCA, which mediates immunosuppressive effects. In this study, the net yield of cis-UCA was measured after the photoisomerization of urocanic acid by narrow UV wavebands (spectral range 295-405 nm), with the irradiation doses related to solar irradiance at sea level. The formation of cis-UCA in Caucasian skin (in vivo), as well as in aqueous solution (in vitro), was determined by HPLC analysis. The same irradiation conditions were met in both components of the study. The in vivo experiments showed high efficiency of cis-UCA formation in the spectral region of 305-341 nm, whereas high efficiency in vitro was found at 305 and 326 nm. At 350 and 363 nm, cis-UCA was formed in vivo, but not in vitro. At longer test wavelengths up to 405 nm, no significant formation of cis-UCA was detectable. Our results demonstrate that the formation of cis-UCA in the skin with common exposures takes place over a broad spectrum range of UVB and UVA, up to at least 363 nm. These findings emphasize the potency of UVA to isomerize UCA, and they may contribute to further elucidation of the effects of phototherapy and sunbathing. (author)

[en] Sites of previously unexposed buttock skin of eight human volunteers (skin type II) were treated daily for 3, 5, 8, or 10 days with suberythemogenic doses of solar-simulated radiation (SSR) in the presence of a UVB sunscreen containing 5-methoxypsoralen (5-MOP) at 30 p.p.m., or daily for 10 days with SSR + the same sunscreen without 5-MOP. One week after cessation of treatment, these sites, together with a control unexposed site, were challenged with 2 minimal erythema doses (2 MED) of SSR. Biopsy samples were taken within 15 min of the challenge dose, and were incubated for 1 h in tritiated thymidine. UV-induced DNA damage was measured indirectly by unscheduled DNA synthesis (UDS), and directly using a monoclonal antibody to thymine dimers, and automated image analysis. The level of pigmentation was assessed in sections in a semiquantitative fashion with Masson-Fontana staining, and the number of layers in the stratum corneum was used to assess changes in epidermal thickness. Using the UDS and dimer measurements, the level of photochemoprotection afforded by 5-MOP was determined from the reduction in the level of DNA damage observed. The photochemoprotection was expressed as a ratio of the 5-MOP-treated sites compared with the sites that did not receive 5-MOP treatment. (Author)

[en] Topical photochemotherapy with psoralen and its derivatives 4,5',8-trimethylpsoralen (TMP) and 8-methoxypsoralen (8-MOP), with UVA irradiation, was evaluated with regard to minimum phototoxic dose, concentration, timing of UVA irradiation and systemic and local side-effects, in healthy volunteers. Psoralen (0.005%) in aqueous gel was found to be superior to TMP and 8-MOP in aqueous gel. No hyperpigmentation was seen after topical PUVA treatment with psoralen in aqueous gel. Patients with plaque-type psoriasis (n=7), palmoplantar psoriasis (n=7) and hyperkeratotic eczema (n=2) were treated. Topical PUVA therapy was effective in most psoriasis patients, without the occurrence of local or systemic side-effects. Moreover, hyperkeratotic eczema patients who did not respond to conventional therapy showed partial remission. These results indicate that topical PUVA therapy with psoralen in aqueous gel is a useful therapeutic modality for treatment of psoriasis patients, and patients with recalcitrant dermatoses such as palmoplantar psoriasis and hyperkeratotic eczema. (author)

[en] A survey, using a postal questionnaire, was carried out to examine the current practice of UVB phototherapy in dermatology centres in the U.K. The questionnaire was sent to 115 dermatology departments, and sought information regarding the type and age of each machine used for ultraviolet B (UVB) phototherapy, methods of prescribing, recording and terminating patient exposure, and the skin conditions treated. Completed questionnaires were received from 87 of the 115 centres, giving a response rate of 76%. The survey showed that an appreciable number of U.K. phototherapy centres are using equipment which is both old, and suboptimal in producing a therapeutic response. There appeared to be a wide variation in the approach to phototherapy, both in terms of prescribing initial and incremental exposure, and in terminating treatment. The findings suggest that effectiveness and efficiency might be improved, and the risk/benefit ratio of phototherapy further reduced, by some rationalization of treatment protocols. (author)

[en] Three short articles constitute the correspondence concerning a report on the testing of SunCheck monitors, devices designed to protect the user from overexposure to ultraviolet radiation. The use of these monitors in conjunction with suncreams is also discussed. (UK)

[en] Short communication

[en] Both cyclosporin (CyA) and ultraviolet radiation are effective in the treatment of psoriasis, but their precise mechanisms of action are uncertain. We investigated their effects on ornithine decarboxylase (ODC) activity, ODC gene expression, and cellular proliferation stimulated by epidermal growth factor (EGF), in cultured normal human epidermal keratinocytes. CyA (5 μg/ml) inhibited ODC activity, ODC mRNA level, and cell growth induced by 50 ng/ml EGF. Ultraviolet B (10 mJ/cm²) irradiation suppressed the induction of ODC, ODC mRNA, and cell proliferation stimulated by EGF, but ultraviolet A (0-15 J/cm²) irradiation inhibited neither EGF-stimulated ODC activity nor cell proliferation. These findings indicate that reduction of ODC activity in CyA- or ultraviolet B-treated human keratinocytes may contribute to the antiproliferative mechanism of these agents. These results also suggest that the regulation of ODC activity by ultraviolet B and A irradiation may be mediated by different signal transduction pathways. (author)

[en] Short communication

[en] Ultraviolet A (UVA) radiation represents an important oxidative stress to human skin and certain forms of oxidative stress have been shown to modulate intercellular adhesion molecule-1 (ICAM-1) expression. ICAM-1 has been shown to play an important part in many immune reactions and the perturbations of this molecule by ultraviolet radiation could have implications in many inflammatory responses. An enhancement immunohistochemical method with avidin/biotin was used for analysing the early effects of UVA radiation on human cell cultures and human skin (340-400 nm). Both in vitro and in vivo data show that ICAM-1 staining in epidermal keratinocytes, which was expressed constitutively, decreased in a UVA dose-dependent manner. The decrease was most noted at 3-6 h following UVA radiation with some ICAM-1 staining returning by 48 h post-UVA. ICAM-1 positive staining in the dermis was specific for vascular structures and was increased 24 h after UVA radiation. Cultured dermal fibroblasts exhibited ICAM-1 staining which increased slightly within 6-48 h post-UVA radiation. As epidermal ICAM-1 expression is depleted following UVA radiation and dermal expression increases due to an increase in the vascular structures, ICAM-1 provides a valuable marker following UVA radiation in human skin that can be readily measured in situ. (author)