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Biomedical subjects

T Ruzicka

Publications and source records attributed to T Ruzicka.

At least 199 records · Page 11Linked to original sources

Calcipotriol cream with or without concurrent topical corticosteroid in psoriasis: tolerability and efficacy.

The objectives of the study were to determine whether concurrent treatment with calcipotriol (50 microg/g) and either clobetasone 17-butyrate cream (0.5 mg/g) (moderate potency) or betamethasone 17-valerate cream (1 mg/g) (potent) or placebo (vehicle of calcipotriol) was more effective and/or caused less skin irritation than calcipotriol cream (50 microg/g) used twice daily. It was a multicentre, double-blind, parallel group study. Patients applied calcipotriol cream in the morning and either vehicle (n = 174), calcipotriol (n = 174), clobetasone (n = 175) or betamethasone creams (n = 176) in the evening for up to 8 weeks. Adverse events led to withdrawal in 20 patients (2.9%). The mean percentage change in PASI (psoriasis area and severity index) was -40.6 in the calcipotriol/vehicle group, -48.3 in the calcipotriol/calcipotriol group, -53.7 in the calcipotriol/clobetasone 17-butyrate group and -57.5 in the calcipotriol/betamethasone 17-valerate group. A statistically significant difference was seen between the four treatment groups (P = 0.006) with calcipotriol/vehicle being less effective than the other treatments. A statistically significant difference in favour of calcipotriol/betamethasone 17-valerate was seen between the calcipotriol/calcipotriol group and the calcipotriol/betamethasone 17-valerate group. The majority of adverse events were skin irritations, which were reported for 31.2% of patients treated with calcipotriol/vehicle, 34.3% of patients treated with calcipotriol twice daily and 23.8% vs. 17.1% of patients treated with calcipotriol/clobetasone 17-butyrate and calcipotriol/betamethasone 17-valerate, respectively. Skin irritation was seen statistically significantly less frequently in patients treated with calcipotriol/ clobetasone 17-butyrate or calcipotriol/betamethasone 17-valerate (P = 0.001), whereas no difference was seen between the other groups. In conclusion, calcipotriol applied twice daily was as effective as calcipotriol/clobetasone 17-butyrate, but slightly less effective than calcipotriol/betamethasone 17-valerate. The incidence of skin irritation was less for patients using concurrent corticosteroids, whereas treatment with calcipotriol/vehicle did not reduce the incidence of skin irritation when compared with calcipotriol twice daily.

Adult↗

Nitric oxide in human skin: current status and future prospects.

The gaseous free radical nitric oxide is an important biologic mediator with physiologic and pathophysiologic roles in nearly every organ system. Because of its unique biologic activity, unusual chemical structure, and unprecedented mechanisms of action, nitric oxide, arguably more than any other natural product, has opened new avenues to investigate cellular processes. Nitric oxide is generated in biologic tissues by specific nitric oxide synthases that metabolize arginine and molecular oxygen to citrulline and nitric oxide. Besides its function as a diffusible messenger in the vasculature and in neurons, nitric oxide also plays a key role in innate immunity and inflammation. Recent progress has allowed the identification of the nitric oxide pathway in several cell types that reside in the skin, including keratinocytes, melanocytes, Langerhans cells, fibroblasts, and endothelial cells. Convincing evidence suggests that nitric oxide synthesis in these cells can be modulated by calcium-mobilizing agonists as well as diverse inflammatory and immune stimuli, and thereby contributes to the pathogenesis of several human skin diseases. Characterization of these intrinsic and extrinsic regulatory stimuli of nitric oxide synthesis has afforded substantial insights into the role of nitric oxide in inflammatory, hyperproliferative, and autoimmune skin diseases, as well as skin cancer, and may ultimately form the basis for future therapeutic intervention. The demonstrable and potential roles of nitric oxide in skin disease pathogenesis and treatment are the subjects of this review.

Humans↗

Aberrant timing in epidermal expression of inducible nitric oxide synthase after UV irradiation in cutaneous lupus erythematosus.

Photosensitivity is a main criterion for the diagnosis of systemic lupus erythematosus (LE), and ultraviolet (UV) irradiation plays a key role in the pathogenesis of cutaneous LE. Patients with a tentative diagnosis of LE are routinely tested for skin lesion development after experimental UV irradiation, providing an ideal opportunity to evaluate early, preclinical events involved in the pathogenesis of LE. Several reports have shown expression of the cytokine-inducible nitric oxide synthase (iNOS) in autoimmune diseases. Therefore, we investigated the role of iNOS expression at mRNA and protein level in the pathogenesis of LE lesions. Skin biopsies from patients with different subtypes of LE were examined, and iNOS expression was found in six of 18 biopsies from cutaneous LE patients and two of three biopsies from systemic LE patients. In biopsies taken 4-20 d after UV irradiation, epidermal iNOS expression was seen in all patients (n = 10) after UVB and in four of 10 patients provoked by UVA. In healthy controls (n = 8) epidermal iNOS expression was detected 24 h after UV irradiation, persisting for another day before subsiding on day 3. In LE patients (n = 8) the exact reverse situation was seen: an iNOS-specific signal was undetectable in keratinocytes for 2 d after UV irradiation, but became positive on day 3 and persisted for up to 25 d in the evolving skin lesions. Our findings demonstrate a time-restricted, UV-induced iNOS expression in human skin; moreover, the results indicate that both the kinetics of iNOS induction as well as the time span of local iNOS expression may be critical to the development of cutaneous LE lesions.

Adult↗

Biphasic effect of exogenous nitric oxide on proliferation and differentiation in skin derived keratinocytes but not fibroblasts.

Nitric oxide (NO) is known to exert cytotoxic and cytostatic effects in various cells and tissues. Although NO formation in human skin has been convincingly demonstrated, little is known about the NO-mediated effects in skin physiology and pathology. Here, we investigate the influence of NO on proliferation, differentiation, and apoptosis of primary cultures of normal human keratinocytes and fibroblasts. Four different NO donors at concentrations ranging from 0.01 to 5 mM were added every 12 h or 24 h to primary cultures of human keratinocytes and fibroblasts, and cells cultured for up to 3 d in the presence of these compounds. Cultures were examined for necrosis or apoptosis using trypan blue exclusion and in situ nick-translation. Cultures were also screened for the expression of the proliferation marker Ki67 and for an increase in cell numbers using neutral red staining. In addition, keratinocytes were stained for cytokeratin 6 expression to assess differentiation. We find that both keratinocytes and fibroblasts are highly resistant towards necrosis- or apoptosis-inducing effects of NO. In both cell types NO modulates cell growth, albeit in a cell-type specific pattern: cytostasis becomes significant in fibroblasts at concentrations of > or = 0.25 mM of the NO donor. In keratinocytes a biphasic effect is found with increased proliferation at low concentrations ranging from 0.01 to 0.25 mM and cytostasis at concentrations of > or = 0.5 mM. Conversely, expression of cytokeratin 6 is decreased at the lower NO donor concentrations and increased at higher concentrations as an indication of induction of differentiation at higher NO concentrations. Collectively, our results demonstrate that NO modulates proliferation and differentiation in human skin cells, a finding that will help to explain the pathophysiology of human skin diseases. Moreover, these findings suggest that NO generation in human skin diseases is not directly associated with local cell destruction, in contrast to findings in several other human diseases.

Cell Differentiation↗

Muir-Torre phenotype has a frequency of DNA mismatch-repair-gene mutations similar to that in hereditary nonpolyposis colorectal cancer families defined by the Amsterdam criteria.

Muir-Torre syndrome (MTS) is an autosomal dominant disease defined by the coincidence of at least one sebaceous skin tumor and one internal malignancy. About half of MTS patients are affected by colorectal cancer. In a subgroup of MTS patients the disease has an underlying DNA mismatch-repair (MMR) defect and thus is allelic to hereditary nonpolyposis colorectal cancer (HNPCC). The purpose of this study was to examine to what extent germ-line mutations in DNA MMR genes are the underlying cause of the MTS phenotype. We ascertained 16 MTS patients with sebaceous skin tumors and colorectal cancer, and we examined their skin and visceral tumors for microsatellite instability. All the patients exhibited high genomic instability in at least one tumor. The search for germ-line mutations in the hMSH2 and hMLH1 genes in 13 of the MTS patients revealed truncating mutations in 9 (69%): eight mutations in the hMSH2 gene and one in the hMLH1 gene. This is the first systematic search for germ-line mutations in patients ascertained on the basis of sebaceous skin tumors. Our results indicate that (1) MTS patients exhibit significantly more mutations in the hMSH2 gene than in the hMLH1 gene; and (2) the subpopulation of MTS patients who are also affected by colorectal cancer, irrespective of family history and age at onset of tumors, may have a likelihood for an underlying DNA MMR defect similar to that for patients with a family history fulfilling the strict clinical criteria for HNPCC.

Adult↗

Pilomatricoma in elderly individuals.

We report on 4 elderly patients aged 54-85 years with histopathologically diagnosed pilomatricoma who had been seen in our department from 1993 to 1997. Pilomatricoma is a rather uncommon neoplasm in middle-aged and old patients. It is much better known in children. Here, we clinically studied these 4 cases of pilomatricoma in elderly patients (above 50 years of age) to show the variety of clinical differential diagnosis and discuss the clinicopathological features. The results of the present study indicate that the differential diagnosis of pilomatricoma should also be considered in elderly individuals.

Adolescent↗

Psoralen photoactivation promotes morphological and functional changes in fibroblasts in vitro reminiscent of cellular senescence.

Premature aging of the skin is a prominent side effect of psoralen photoactivation, a treatment used widely for various skin disorders. The molecular mechanisms underlying premature aging upon psoralen photoactivation are as yet unknown. Here we show that treatment of fibroblasts with 8-methoxypsoralen (8-MOP) and subsequent ultraviolet A (UVA) irradiation resulted in a permanent switch of mitotic to stably postmitotic fibroblasts which acquired a high level of de novo expression of SA-beta-galactosidase, a marker for fibroblast senescence in vitro and in vivo. A single exposure of fibroblasts to 8-MOP/UVA resulted in a 5.8-fold up-regulation of two matrix-degrading enzymes, interstitial collagenase (MMP-1) and stromelysin-1 (MMP-3), over a period of >120 days, while TIMP-1, the major inhibitor of MMP-1 and MMP-3, was only slightly induced. This imbalance between matrix-degrading metalloproteases and their inhibitor may lead to connective tissue damage, a hallmark of premature aging. Superoxide anion and hydrogen peroxide, but not singlet oxygen, were identified as important intermediates in the downstream signaling pathway leading to these complex fibroblast responses upon psoralen photoactivation. Collectively, the end phenotype induced upon psoralen photoactivation shares several criteria of senescent cells. In the absence of detailed molecular data on what constitutes normal aging, it is difficult to decide whether the changes reported here reflect mechanisms underlying normal cellular aging/senescence or rather produce a mimic of cellular aging/senescence by quite different pathways.

Cell Division↗

Differential accumulation of iodine-123-iodobenzamide in melanotic and amelanotic melanoma metastases in vivo.

UNLABELLED: Iodine-123-iodobenzamide (IBZM) is a specific antagonist of dopamine D2 receptors and usually is used to study neuropsychiatric disorders. It also has a substantial affinity for malignant melanomas. This has been attributed to specific dopamine D2 receptor binding on melanoma cells because melanocytes and dopaminergic neurons share the same ectodermal origin and are both able to produce melanin. However, IBZM binding to melanoma metastases occurs predominantly 24 hr after injection, which is much later than maximal specific D2 receptor binding is expected. Furthermore, IBZM binding is not consistent in melanoma patients. This points to another mechanism of IBZM binding to melanoma cells. The aim of this study was to characterize IBZM-binding metastatic melanoma patients clinically and histologically to shed light on the nature of this mechanism. METHODS: Twenty-one patients with proven or suspected metastases of a malignant melanoma entered this prospective study after surgical removal of the primary tumor. Whole-body scans, planar scintigrams and SPECT scans were performed 2-5 hr and 1 day after intravenous injection of 185 MBq IBZM. RESULTS: The suspected diagnosis of metastatic cancer was later confirmed in 17 patients by histology, clinical follow-up, x-ray, CT or other radiologic methods. Four patients were free of tumor tissue at the time of investigation and remained stable for 2 yr thereafter. Twelve of the 17 patients had a melanotic and 5 had an amelanotic subtype of the tumor. Iodine-123-IBZM accumulation occurred in the metastases of 10 of the 12 patients with melanotic melanoma and in 0 of the 5 patients with the amelanotic tumor type (p < 0.01; chi-square test). Furthermore, IBZM accumulation occurred in 0 of the 11 amelanotic metastases but in 20 of the 25 melanotic metastases (p < 0.001). The sensitivity is, thus, 83% for the detection of melanotic melanoma metastases on a patient basis and 80% on a lesion basis. Iodine-123-IBZM scintigraphy demonstrated one previously unknown metastasis. Six initially suspected lesions were not due to melanoma metastases and were IBZM-negative. No false-positive IBZM accumulations occurred in our patients. CONCLUSION: Iodine-123-IBZM binds to melanotic malignant melanomas with high specificity and moderate sensitivity but not to amelanotic melanomas. Our data suggest that the tracer does not bind to membrane dopamine receptors of the tumor but is built in or closely bound to intracellular melanin.

Adult↗

Preferential relative porphyrin enrichment in solar keratoses upon topical application of delta-aminolevulinic acid methylester.

Topically applied delta-aminolevulinic acid is used efficiently for the treatment of solar keratoses by photodynamic therapy. Recent animal studies suggest that porphyrin sensitization of epithelial tissue is improved by using esters rather than free delta-aminolevulinic acid. The present study examines porphyrin metabolite formation after topical application of delta-aminolevulinic acid or delta-amino-levulinic acid methylester in human solar keratoses versus adjacent normal skin. Level of total porphyrins, porphyrin metabolites and protein were measured in skin samples excised after 1 and 6 h. Higher levels of porphyrins were observed in solar keratoses than in normal skin with both substances. Maximum porphyrin levels were present in solar keratoses treated with delta-aminolevulinic acid for 6 h. However, the ratio of porphyrins in solar keratoses versus adjacent normal skin was higher with delta-aminolevulinic acid methylester. The pattern of porphyrins showed no significant difference between normal and afflicted skin, protoporphyrin being predominant. The results suggest that application of free delta-aminolevulinic acid may be more effective in sensitizing solar keratoses. However, treatment with delta-aminolevulinic acid methylester leads to a preferential enrichment of porphyrins within lesional skin.

Administration, Topical↗

Demonstration and functional analysis of IL-10 receptors in human epidermal cells: decreased expression in psoriatic skin, down-modulation by IL-8, and up-regulation by an antipsoriatic glucocorticosteroid in normal cultured keratinocytes.

The chronic skin disease psoriasis is characterized by epidermal hyperproliferation and inflammation. The exact etiology of the disease is still unknown. At the molecular level, overexpression of growth factors and proinflammatory cytokines such as IL-8 and the corresponding receptor has been described in psoriatic plaques. On the other hand, the loss of inhibitory control mechanisms is involved in the pathogenesis of the disease, as exemplified by the reduced mRNA levels for the cell cycle inhibitor p53 found in lesional skin. Here we extend these findings to a cytokine with negative regulatory functions, IL-10. Only under certain conditions are human keratinocytes able to synthesize IL-10. In skin, pathological overexpression of IL-10 was described om atopic dermatitis. IL-10 exerts its effects via a specific receptor (IL-10R). We show here for the first time the presence and functionality of IL-10R in epidermal cells and its dramatically decreased expression in acute exanthematic psoriatic epidermis by in vitro and in situ binding studies. These results were substantiated using semiquantitative reverse transcriptase-PCR, demonstrating decreased expression of the IL-10R gene in psoriatic skin, its down-modulation by the proinflammatory cytokine IL-8, and its pharmacological induction in cultured cells. Biological responsiveness of epidermal cells toward IL-10 could also be demonstrated by a reduction of the growth rate and inhibition of IFN-gamma-induced HLA-DR expression. Our results provide the first evidence for a role of the IL-10R gene in the homeostasis of the epidermis and substantiate the concept of a loss of negative regulatory peptides as a step in the eruption of psoriasis.

Acute Disease↗

Evidence that singlet oxygen-induced human T helper cell apoptosis is the basic mechanism of ultraviolet-A radiation phototherapy.

Ultraviolet A (UVA) irradiation is effectively used to treat patients with atopic dermatitis and other T cell mediated, inflammatory skin diseases. In the present study, successful phototherapy of atopic dermatitis was found to result from UVA radiation-induced apoptosis in skin-infiltrating T helper cells, leading to T cell depletion from eczematous skin. In vitro, UVA radiation-induced human T helper cell apoptosis was mediated through the FAS/FAS-ligand system, which was activated in irradiated T cells as a consequence of singlet oxygen generation. These studies demonstrate that singlet oxygen is a potent trigger for the induction of human T cell apoptosis. They also identify singlet oxygen generation as a fundamental mechanism of action operative in phototherapy.

Antibodies, Blocking↗

A short-term trial of tacrolimus ointment for atopic dermatitis. European Tacrolimus Multicenter Atopic Dermatitis Study Group.

BACKGROUND: Tacrolimus (FK 506) is an effective immunosuppressant drug for the prevention of rejection after organ transplantation, and preliminary studies suggest that topical application of tacrolimus is effective in the treatment of atopic dermatitis. METHODS: We conducted a randomized, doubleblind, multicenter study that compared 0.03 percent, 0.1 percent, and 0.3 percent tacrolimus ointment with vehicle alone in patients with moderate to severe atopic dermatitis. The ointment was applied twice daily to a defined, symptomatic area of 200 to 1000 cm2 of skin for three weeks. The primary end point was the change in the summary score for erythema, edema, and pruritus between the first and last days of treatment. RESULTS: After three weeks of treatment, the median percentage decrease in the summary score for dermatitis on the trunk and extremities was 66.7 percent for the 54 patients receiving 0.03 percent tacrolimus, 83.3 percent for the 54 patients receiving 0.1 percent tacrolimus, 75.0 percent for the 51 patients receiving 0.3 percent tacrolimus, and 22.5 percent for the 54 patients receiving vehicle alone (P<0.001). The results for the face and neck were similar. The differences among the three tacrolimus groups were not statistically significant. A sensation of burning at the site of application was the only adverse event that was significantly more frequent with tacrolimus than with vehicle alone (P<0.001). Throughout the study, most patients in all three tacrolimus groups had blood concentrations of tacrolimus below 0.25 ng per milliliter. The highest concentration was 4.9 ng per milliliter, which was reported in the group receiving 0.3 percent tacrolimus. CONCLUSIONS: The short-term application of tacrolimus ointment is effective in the treatment of atopic dermatitis, with the sensation of burning being the main side effect.

Administration, Cutaneous↗

Mutations in the human homologue of the Drosophila segment polarity gene patched (PTCH) in sporadic basal cell carcinomas of the skin and primitive neuroectodermal tumors of the central nervous system.

The human homologue of the Drosophila segment polarity gene patched (PTCH) has recently been identified as the tumor suppressor gene responsible for the nevoid basal cell carcinoma (BCC) syndrome (H. Hahn et al., Cell, 85: 841-851, 1996; R. L. Johnson et al., Science (Washington DC), 272: 1668-1671, 1996). In addition to multiple BCCs, patients with nevoid BCC syndrome have a predisposition for the development of primitive neuroectodermal tumors (PNETs) of the central nervous system. We have analyzed 9 sporadic BCCs and 37 PNETs for mutation and expression of the PTCH gene. PTCH mutations were found in 3 BCCs (33.3%) and in 5 PNETs (14%), including 1 of 5 cerebral PNETs, 2 of 15 medulloblastomas, and 2 of 17 desmoplastic medulloblastomas. The sequence changes in six of these tumors (four PNETs, two BCCs) were mutations predicted to result in truncated proteins. Missense mutations were detected in one PNET and one BCC each. In addition, novel sequence polymorphisms were found in exon 2, intron 5, intron 10, and intron 14 of PTCH. Reverse transcription-PCR analysis revealed increased PTCH expression levels compared to nonneoplastic brain tissue and normal skin in the majority of PNETs and BCCs investigated. Our data suggest that genetic alterations of PTCH are not only of significance in hereditary and sporadic BCCs but are also involved in the molecular pathogenesis of a subset of sporadic central nervous system PNETs.

Adolescent↗

A local lymph node assay to analyse immunosuppressive effects of topically applied drugs.

Topical glucocorticosteroids represent the mainstay of antiinflammatory therapy in the treatment of inflammatory skin diseases. Their clinical use, however, is limited by local and systemic side-effects. Thus, in dermatopharmacology there is a large demand for alternative non-steroidal antiinflammatories. Other than transplantation models, most of the frequently used in vivo test systems for assessment of drug-induced immunosuppression measure changes in inflammatory skin responses by means of skin erythema and edema after challenge of sensitized animals. The aim of this study was to develop an alternative mouse model to detect and analyse immunosuppressive effects of topically applied drugs. On the basis of a modified local lymph node assay, we analysed effects of topical hydrocortisone, dexamethasone, mometasone furoate and FK506 (tacrolimus) during the induction phase of contact hypersensitivity. On 4 consecutive days, NMRI mice were treated on the dorsal surfaces of both ears with increasing concentrations of test compound. During the last 3 days, the mice received in addition the contact sensitizer, oxazolone (1%). On day 5, draining auricular lymph nodes were removed in order to assess lymph node cell counts and perform flow cytometric analysis of lymph node cell subpopulations (CD4+/CD25+, Ia+/CD69+, Ia+/B220+). All test compounds proved to exert significant immunosuppressive effects after topical application, but showed differences in their immunomodulatory potential. In conclusion, the local lymph node assay serves as an appropriate model to characterize immunosuppressive effects of topically applied drugs by measuring immunologically relevant end-points.

Administration, Topical↗

1,25-(OH)2-vitamin D3 and calcipotriol induce IL-10 receptor gene expression in human epidermal cells.

Psoriasis is a common hyperproliferative and inflammatory skin disease with a prevalence of 0.5-3%. Lesional skin is characterized by pathological overexpression of proinflammatory cytokines such as IL-8 and its receptor and the decreased presence of negative regulatory control factors like the anti-oncogene p53. The expression of these genes can be modulated in the opposite direction by antipsoriatic drugs. Another possible candidate gene is the receptor for the anti-inflammatory cytokine IL-10 (IL-10R). Recently, vitamin D3 and its analogues have attracted interest as new therapeutic agents in the treatment of psoriasis. In extension of these findings we studied here the effect of the physiologically active metabolite, 1,25-dihydroxyvitamin D3 (calcitriol) and its synthetic analogue calcipotriol (MC 903) on the expression of the IL-10R in HaCaT cells by RT-PCR. IL-10 receptor gene expression was effectively induced in the range of 10(-8)-10(-9) M. Upregulation by calcitriol was about 10-fold, by calcipotriol 12-fold. Induction of the receptor for the anti-inflammatory cytokine IL-10 may be involved in the antipsoriatic action of vitamin D derivatives.

Calcitriol↗

[Resistance to activated protein C by mutation of the factor V gene. Most frequent blood coagulation defect in venous thromboses].

Deep venous thromboses, in particular when recurrent, can be associated with chronic venous leg ulcers. Such complications are often seen in dermatology departments and frequently represent a therapeutic problem. Resistance to activated protein C (APCR) has recently been identified as the most frequent coagulation defect associated with an increased risk of venous thrombosis. In most cases, APCR is caused by a point mutation in the factor V gene which results in an impaired inactivation of activated factor V (Va). As a consequence of this, an important anti-coagulant mechanism in the physiological balance of the hemostatic system is abolished. This autosomal dominantly inherited genetic defects affects about 5% of the general population. In this article we draw attention to the existence of this recently identified, genetically determined risk factor for venous thrombosis, describe recent diagnostic developments and discuss therapeutic options.

Chromosome Aberrations↗

[Cream PUVA photochemotherapy].

Bath-PUVA-photochemotherapy lacks systemic side effects and requires low cumulative UVA doses, but a major disadvantage is the logistical requirement for bath tubs in a practice. We have developed an alternative form of topical PUVA therapy using a lipophilic emulsion vehicle for the photosensitizer 8-MOP (cream-PUVA-photochemo-therapy). A 0.0006% 8-MOP containing water-in-oil emulsion (30% H2O) was optimal for inducing photosensitivity in treated skin areas without increasing 8-MOP plasma levels. Increased skin photosensitivity was maximal 1 hour after cream application and persisted for 3 hours. We next assessed the effectiveness of cream-PUVA-photochemotherapy in the treatment of patients with chronic recalcitrant palmoplantar eczema (n = 10). In seven patients complete, and in two patients partial, remissions were observed after 40 treatments. Thus, cream-PUVA-photochemotherapy, which is easier to perform than bath-PUVA-photochemotherapy, is an effective, safe and low-cost modality, which may prove to become the topical PUVA therapy of choice for dermatological practitioners.

Dose-Response Relationship, Drug↗