Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 140
Filtrar
1.
J Eur Acad Dermatol Venereol ; 35(12): 2448-2455, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34459043

RESUMO

BACKGROUND: Photodiagnostic investigations are essential for the accurate diagnosis of abnormal cutaneous photosensitivity and provide important information for the management of patients with photodermatoses (cutaneous photosensitivity disorders). Although photodiagnosis has been undertaken since the early 1970s, specialist services in the United Kingdom (UK) and Republic of Ireland are limited and there is no formal guidance on diagnostic approach. Indeed, there is a limited literature in this area of methodology and diagnostic practice. OBJECTIVES: The primary objective was to undertake a British Photodermatology Group Workshop to review the role and activities of specialist centres in the UK and Republic of Ireland in order to ascertain whether there were consensus practices. Secondary objectives were to identify key priorities for service, training and research. METHODS: An initial detailed survey review of current activities was undertaken prior to the Workshop and data from this survey were used to inform discussion at the Workshop, which was attended by key photodermatology experts from the UK and Republic of Ireland. RESULTS/CONCLUSIONS: We have undertaken a detailed review of current Photodiagnostic Services in the UK and Republic of Ireland and report on our findings from the 12 centres and we have identified key areas of consensus practice. This is an important step in the process of standardising and optimising procedures and protocols and defining minimum clinical standards for photodiagnostic investigations, which are of such diagnostic importance in Dermatology.


Assuntos
Dermatopatias , Humanos , Irlanda , Inquéritos e Questionários , Reino Unido
2.
Br J Dermatol ; 179(1): 63-71, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29235664

RESUMO

BACKGROUND: Hand eczema is a common inflammatory dermatosis that causes significant patient morbidity. Previous studies comparing psoralen-ultraviolet A (PUVA) with narrowband ultraviolet B (NB-UVB) have been small, nonrandomized and retrospective. OBJECTIVES: To conduct an observer-blinded randomized controlled pilot study using validated scoring criteria to compare immersion PUVA with NB-UVB for the treatment of chronic hand eczema unresponsive to topical steroids. METHODS: Sixty patients with hand eczema unresponsive to clobetasol propionate 0·05% were randomized to receive either immersion PUVA or NB-UVB twice weekly for 12 weeks with assessments at intervals of 4 weeks. The primary outcome measure was the proportion of patients achieving 'clear' or 'almost clear' Physician's Global Assessment (PGA) response at 12 weeks. Secondary outcome measures included assessment of the modified Total Lesion and Symptom Score (mTLSS) and the Dermatology Life Quality index (DLQI). RESULTS: In both treatment arms, 23 patients completed the 12-week assessment for the primary outcome measure. In the PUVA group, five patients achieved 'clear' and eight 'almost clear' [intention-to-treat (ITT) response rate 43%]. In the NB-UVB group, two achieved 'clear' and five 'almost clear' (ITT response rate 23%). For the secondary outcomes, median mTLSS scores were similar between groups at baseline (PUVA 9·5, NB-UVB 9) and at 12 weeks (PUVA 3, NB-UVB 4). Changes in DLQI were similar, with improvements in both groups. CONCLUSIONS: In this randomized pilot trial recruitment was challenging. After randomization, there were acceptable levels of compliance and safety in each treatment schedule, but lower levels of retention. Using validated scoring systems - PGA, mTLSS and DLQI - as measures of treatment response, the trial demonstrated that both PUVA and NB-UVB reduced the severity of chronic palmar hand eczema.


Assuntos
Eczema/tratamento farmacológico , Dermatoses da Mão/tratamento farmacológico , Terapia PUVA/métodos , Adulto , Idoso , Esquema de Medicação , Feminino , Ficusina/administração & dosagem , Ficusina/efeitos adversos , Humanos , Masculino , Pessoa de Meia-Idade , Terapia PUVA/efeitos adversos , Fármacos Fotossensibilizantes/administração & dosagem , Fármacos Fotossensibilizantes/efeitos adversos , Projetos Piloto , Estudos Prospectivos , Método Simples-Cego , Raios Ultravioleta , Adulto Jovem
3.
Br J Dermatol ; 170(2): 392-7, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24125495

RESUMO

BACKGROUND: Photoadaptation describes the skin's ability to withstand an increased dose of ultraviolet (UV) radiation with repeated exposure, and this is the reason for exposure doses being increased during a course of phototherapy. However, directly measured data on photoadaptation are available only for broadband (BB) and not narrowband (NB)-UVB. OBJECTIVES: To measure photoadaptation to narrowband UVB. METHODS: We measured the degree of photoadaptation in patients with psoriasis during a standard course of NB-UVB phototherapy. The minimal erythemal dose (MED) was measured before and towards the end of a course of phototherapy. An adaptation factor (AF) was calculated for each patient using the ratio of final MED to initial MED. Sigmoid dose-response curves were also constructed. RESULTS: MED results were available for 50 patients (mean age 44 years, 28 female). The mean AF was 2·7 (95% confidence interval 2·4-3·0). There was no significant correlation between AF and skin type or initial MED. Dose-response curves were right shifted and parallel after phototherapy, and there was no significant difference in the maximum slope (P = 0·73). CONCLUSIONS: The photoadaptation caused by NB-UVB is considerably less than that reported for BB-UVB. The variation in photoadaptation between patients was not explained by skin type or baseline MED. Physical factors (such as tanning and epidermal thickening) are probably sufficient to account for photoadaptation, rather than downregulation of the inflammatory response. These data should help in the design of phototherapy protocols for NB-UVB to achieve optimal clearance of psoriasis.


Assuntos
Adaptação Fisiológica/efeitos da radiação , Pele/efeitos da radiação , Raios Ultravioleta , Adulto , Relação Dose-Resposta à Radiação , Feminino , Humanos , Masculino , Psoríase/radioterapia , Radiometria , Terapia Ultravioleta/métodos
7.
Br J Dermatol ; 166(2): 380-8, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21967523

RESUMO

BACKGROUND: There is marked interpatient variation in responses to psoralen-ultraviolet A (PUVA) photochemotherapy. Identification of molecular biomarkers of PUVA sensitivity may facilitate treatment predictability.The glutathione S-transferases (GSTs) influence cutaneous defence against UV radiation-induced oxidative stress and are therefore candidate biomarkers of PUVA sensitivity. Several human GSTs, including GSTM1 and GSTT1, are polymorphic, and null polymorphisms have been associated with increased UVB erythemal sensitivity and skin cancer risk. PUVA also increases skin cancer risk. OBJECTIVES: To investigate the effect of GST genotype on PUVA sensitivity. METHODS: We investigated GST genotype in patients starting PUVA (n=111) and the effects of 8-methoxypsoralen (8-MOP) on antioxidant response element (ARE)-regulated gene expression in mammalian cells. RESULTS: Lower minimal phototoxic doses (MPD) (P=0·022) and higher serum 8-MOP concentrations (P=0·052) were seen in GSTM1-null allele homozygotes compared with patients with one or two active alleles. In a subset of patients with psoriasis (n=50), the GSTM1 genotype was not associated with PUVA outcomes, although MPD [hazard ratio (HR) 1·37; 95% confidence interval (CI) for HR 1·15-1·64] and GSTT1-null (HR 2·39; 95% CI for HR 1·31-4·35) and GSTP1b (HR 1·96; 95% CI for HR 1·10-3·51) genotypes were associated with clearance of psoriasis in this patient group. Exposure of mammalian cells to 8-MOP induced gene expression via the ARE, a regulatory sequence in promoters of cytoprotective genes including GSTs, suggesting that these genes may be implicated in 8-MOP metabolism. CONCLUSION: The polymorphic human GSTs are associated with PUVA sensitivity. Further studies are required to examine the clinical relevance of these preliminary findings.


Assuntos
Glutationa Transferase/genética , Metoxaleno/administração & dosagem , Terapia PUVA/métodos , Fármacos Fotossensibilizantes/administração & dosagem , Polimorfismo Genético/genética , Psoríase/genética , Adolescente , Adulto , Idoso , Relação Dose-Resposta a Droga , Eritema/induzido quimicamente , Feminino , Expressão Gênica , Genótipo , Glutationa S-Transferase pi/genética , Humanos , Masculino , Metoxaleno/sangue , Pessoa de Meia-Idade , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/efeitos da radiação , Transtornos de Fotossensibilidade/genética , Fármacos Fotossensibilizantes/sangue , Psoríase/tratamento farmacológico , Recidiva , Elementos de Resposta/genética , Resultado do Tratamento , Adulto Jovem
8.
FASEB J ; 22(12): 4218-27, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18708588

RESUMO

The nuclear factor of activated T cells (NFAT) transcription factors are regulated by calcium/calcineurin signals and play important roles in T cells, muscle, bone, and neural tissue. NFAT is expressed in the epidermis, and although recent data suggest that NFAT is involved in the skin's responses to ultraviolet radiation (UVR), the wavelengths of radiation that activate NFAT and the biological function of UV-activated NFAT remain undefined. We demonstrate that NFAT transcriptional activity is preferentially induced by UVB wavelengths in keratinocytes. The derived action spectrum for NFAT activation indicates that NFAT transcriptional activity is inversely associated with wavelength. UVR also evoked NFAT2 nuclear translocation in a parallel wavelength-dependent fashion and both transcriptional activation and nuclear translocation were inhibited by the calcineurin inhibitor cyclosporin A. UVR also evoked NFAT2 nuclear translocation in three-dimensional skin equivalents. Evidence suggests that COX-2 contributes to UV-induced carcinogenesis. Inhibiting UV-induced NFAT activation in keratinocytes, reduced COX-2 protein induction, and increased UV-induced apoptosis. COX-2 luciferase reporters lacking functional NFAT binding sites were less responsive to UVR, highlighting that NFAT is required for UV-induced COX-2 induction. Taken together, these data suggest that the proinflammatory, antiapoptotic, and procarcinogenic functions of UV-activated COX-2 may be mediated, in part, by upstream NFAT signaling.


Assuntos
Ciclo-Oxigenase 2/biossíntese , Queratinócitos/enzimologia , Queratinócitos/efeitos da radiação , Fatores de Transcrição NFATC/fisiologia , Raios Ultravioleta , Linhagem Celular , Ciclosporina/farmacologia , Indução Enzimática , Humanos , Queratinócitos/efeitos dos fármacos , Transporte Proteico/efeitos da radiação , Ativação Transcricional/efeitos da radiação
9.
Rev Med Brux ; 30(4): 304-8, 2009 Sep.
Artigo em Francês | MEDLINE | ID: mdl-19899377

RESUMO

The occupational physician (OP) and the general practitioner (GP) both aim at maintaining and promoting public health. The attending physician is the physician who has been freely chosen by the patient whilst the occupational physician is assigned by the company. Although synergy between both professions might seem obvious, in reality it is not always so. The focus of the occupational physician's work is on the worker in his work place. Through health monitoring action and knowledge of jobs and positions, the occupational physician aims to contribute to the improvement of well-being at work. Medical examinations result in drafting a form stating the person's ability or inability to occupy his/her assigned job. In line with the required respect for the patient's rights and, hence, with his/her authorization, the GP may transmit the medical information the said GP deems useful to the OP, e.g. back-to-work medical examinations and pre-back-to-work medical consultations are opportunities to establish a contact between both practitioners in view of considering the possibilities of adapting the workplace situation at the time of resumption of work. The GP should know that there exists an appeal opportunity with the Office in charge of Monitoring Well-being at Work (Employment Federal Public Service) against a decision that by which the worker is not allowed to stay in his assigned work task. During the medical examinations the OP may endorse the action of the GP by strengthening the worker/patient's awareness of the fact that his/her health problems must be adequately taken into account and by organizing information sessions about general interest campaigns about, for instance, cardiovascular risk prevention or a campaign about quitting smoking or reducing alcohol consumption to a more sensible and reasonable level. Knowledge of delayed effects of professional exposure should be consolidated in GPs; the possibility of drawing attention to one's suspicions about occupational illnesses to the Fund for Occupational Illnesses must also again brought to mind. In order to establish a follow-up program on the health of patients beyond their professional activity, it is necessary to draft a "liaison document", between the OP and the GP, which identifies the professional risks workers/patients have been exposed to. In sum, it is important to provide GPs with means to identify the patient's OP and consolidate their knowledge of occupational medicine by organizing on-going training modules.


Assuntos
Medicina de Família e Comunidade/estatística & dados numéricos , Relações Interprofissionais , Medicina do Trabalho/estatística & dados numéricos , Médicos , Tomada de Decisões , Emprego/estatística & dados numéricos , Humanos , Exposição Ocupacional , Exame Físico , Fatores de Risco
10.
Rev Med Brux ; 30(4): 297-303, 2009 Sep.
Artigo em Francês | MEDLINE | ID: mdl-19899376

RESUMO

Occupational medicine is an important medical discipline in Belgium, with about one thousand of experts. Roles of the occupational physicians must be analyzed on the basis both of legal prescriptions and real practice. The examination of the roles of the occupational physician in various countries shows that regulation are an important legal framework from which he can deploy his practice. A contrario it is also the means which makes it possible to the unions and the management to force him. However the real roles are definitely broader than the regulations let understand, concerning very diverse fields which make this medical discipline a real preventive general medicine. It is less and less a public health discipline and approaches gradually in practice the clinical disciplines, in the sense that the singular colloquium, the knowledge of the particular work places and risks of every worker and the individualization of the action are its bases. On the other hand, fitness for work assessments and its procession of authoritarian medical and administrative acts, heritages of the public health, hardly efficient, should largely disappear from the prescriptions. It will allow for a wider deployment of the activity of the occupational physician towards the industrial organisations, by proposing the necessary adaptations of the work places, the limitations of exposure to harmful effects, the remediation of the psychosocial load, etc, through "preventive prescriptions". Complementarily, the population ageing imposes new solutions to rehabilitate the old workers, and this will be likely to modify, not only the medical approach in work environment, but also already imposes a closer cooperation with the general practitioner, which is likely to improve the action abilities of both medical disciplines.


Assuntos
Medicina do Trabalho/tendências , Bélgica , Emprego , França , Humanos , Medicina do Trabalho/legislação & jurisprudência , Aptidão Física , Reino Unido , Estados Unidos
11.
Rev Med Brux ; 30(4): 318-25, 2009 Sep.
Artigo em Francês | MEDLINE | ID: mdl-19899379

RESUMO

The missions of the Occupational Diseases Fund are defined in application of the law regarding the insurance against occupational diseases. The workers covered by this law are granted several rights, such as a financial compensation in case of temporary or permanent disability, a further compensation if they have to be taken away from the risk in the workplace, the reimbursement of health care costs related to the occupational disease, or the payment of an annuity to the widow(er) if death is its ultimate consequence. Among the compensable diseases, we shall focus on lung cancer, and especially the one related to asbestos exposure. This type of cancer is clearly under-registrated in Belgium as in most countries of the European Union, leading to an insufficient number of cases entitled to compensation by our institution. In this instance, the insurance against occupational diseases and all related social advantages are hugely under-exploited in our country. It is our duty to increase doctors' awareness of the problem and spread accurate information to reverse this trend and provide occupational cancer cases with a legitimate compensation, in particular those related to asbestos. A wider knowledge of the occupational history of cancer patients, thanks to occupational physicians, and a better use of mineralogical analyses on lung samples, would improve this situation inacceptable on any level : medical, social or even human.


Assuntos
Amianto/toxicidade , Bélgica/epidemiologia , Carcinógenos/toxicidade , União Europeia/estatística & dados numéricos , Humanos , Neoplasias Pulmonares/economia , Neoplasias Pulmonares/epidemiologia , Doenças Profissionais/induzido quimicamente , Doenças Profissionais/economia , Doenças Profissionais/epidemiologia , Exposição Ocupacional/economia , Exposição Ocupacional/estatística & dados numéricos , Garantia da Qualidade dos Cuidados de Saúde
12.
Br J Dermatol ; 159(1): 192-7, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18460025

RESUMO

BACKGROUND: Polymorphic light eruption and erythropoietic protoporphyria (EPP) have been demonstrated to have a moderate and large impact on the quality of life (QoL) of patients, respectively. However, there is little information available about the impact of other photodermatoses on QoL. OBJECTIVES: To assess and compare the impact of all forms of photodermatoses on patients' QoL using the standard 1-week Dermatology Life Quality Index (DLQI) questionnaire and a modified questionnaire to assess the impact over the previous year. METHODS: All patients with photodermatoses seen between 2001 and 2005 at five U.K. photobiology centres were contacted by post on the same day during a forecasted sunny week across the U.K. and asked to complete DLQI questionnaires. RESULTS: A total of 1877 patients were contacted. Seven hundred and ninety-seven (42%) patients replied, with a range from 30% to 48% for the five individual centres. Nearly two-thirds of patients with actinic prurigo (AP) and more than one-third of patients with photoaggravated dermatoses (PAD), chronic actinic dermatitis, EPP and solar urticaria had a DLQI of > 10, confirming a very large effect of the disorders on QoL. Of the cutaneous porphyrias, both variegate porphyria (median DLQI 3) and porphyria cutanea tarda (median DLQI 1.5) had a much lower impact on QoL than EPP. CONCLUSION: This is the first large-scale study to attempt to measure the impact of a range of photodermatoses on QoL. Photodermatoses have a major impact on QoL. This impact is highest in AP and PAD.


Assuntos
Transtornos de Fotossensibilidade/psicologia , Qualidade de Vida , Estudos Transversais , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Cooperação do Paciente/psicologia , Índice de Gravidade de Doença , Inquéritos e Questionários
13.
Cancer Res ; 53(12): 2697-9, 1993 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-8504406

RESUMO

We report that, in human skin, exposure to equally erythemogenic doses of UVA, UVB, and UVC increases immunocytochemically detected p53 in a wavelength-specific pattern. UVC produced immunostaining confined to the upper epidermis. With UVB, staining was seen throughout the epidermis, whereas with UVA staining predominated in the basal layer. The results with UVB and UVC are understandable on the basis of their known differences in penetration, whereas those with UVA are not. This suggests that within one cell type the pattern of p53 response to UV radiation is wavelength dependent.


Assuntos
Expressão Gênica/efeitos da radiação , Genes p53/efeitos da radiação , Pele/efeitos da radiação , Raios Ultravioleta , Adulto , Humanos , Masculino , Pessoa de Meia-Idade , Pele/química , Proteína Supressora de Tumor p53/análise , Raios Ultravioleta/classificação
14.
J Invest Dermatol ; 113(3): 346-50, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10469332

RESUMO

The time-course for the development of ultraviolet A-induced erythema in psoralen-sensitized skin differs from that caused by ultraviolet B or ultraviolet A but objective data are not available. During psoralen ultraviolet A therapy, the minimal phototoxic dose is determined 72 h after exposure, when psoralen ultraviolet A erythema is assumed to be maximal. This measurement is of fundamental importance in optimizing the therapeutic regimen. We examined a detailed time-course for development of psoralen ultraviolet A erythema in 16 subjects. The erythemal responses to ultraviolet B, ultraviolet A and psoralen ultraviolet A were assessed visually and using a reflectance device. Ultraviolet B erythema was maximal 24 h after exposure compared with subsequent time-points. Psoralen ultraviolet A erythema was evident at 24 h, with reduction in the median ultraviolet A minimal erythema dose from 14 to 5 J per cm2 in the presence of psoralen (p < 0.01; n = 9). Peak psoralen ultraviolet A erythema, assessed by minimal phototoxic dose, did not occur until 96 h or later in 75% of subjects. Using individual dose- response curves, we determined that only 67% of mean maximum psoralen ultraviolet A erythemal intensity had developed by 72 h. Furthermore, at the time of maximal erythema, the slope of the psoralen ultraviolet A dose-response curve was approximately 2-fold shallower than that for ultraviolet B-induced erythema. If assessment of psoralen ultraviolet A erythemal sensitivity had been made at 96 h instead of the conventional 72 h time-point, peak erythemal responses would not have been missed in any of the subjects. Based on these findings, it seems appropriate to consider whether psoralen ultraviolet A minimal phototoxic dose measurements should be performed 96 h after exposure.


Assuntos
Eritema/etiologia , Terapia PUVA/efeitos adversos , Adulto , Idoso , Relação Dose-Resposta à Radiação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Tempo
15.
J Invest Dermatol ; 87(6): 771-4, 1986 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-3097159

RESUMO

Terfenadine, given in sufficient dose to cause maximum H1 receptor blockade, had no effect on the intensity of UVB or UVC erythema measured with a reflectance instrument at 4, 8, and 24 h after irradiation. Histamine, acting on the H1 receptor, is not a significant mediator of UVB or UVC erythema.


Assuntos
Compostos Benzidrílicos/uso terapêutico , Eritema/etiologia , Lesões Experimentais por Radiação , Raios Ultravioleta , Adulto , Animais , Relação Dose-Resposta à Radiação , Eritema/induzido quimicamente , Eritema/patologia , Feminino , Histamina/farmacologia , Humanos , Masculino , Terfenadina
16.
J Invest Dermatol ; 117(5): 1318-21, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11710951

RESUMO

Psoriasis may be treated with ultraviolet B from lamps that have a broad emission spectrum or, more effectively, with lamps that have a narrow emission spectrum at 311 +/- 2 nm. There are conflicting reports of either greater or lesser burning episodes with narrow-band compared to broad-band ultraviolet B, even when treatments are based on predetermined minimal erythema dose measurements. This suggests that either the characteristics of the dose-response curve for erythema or the time course for erythema may be different for the two lamps. We examined the erythemal response to narrow-band and broad-band ultraviolet B in 12 patients with psoriasis. A geometric series of 10 doses from each lamp type were used on nonlesional skin on the back. Dose-response curves were constructed from reflectance measurements of erythema at 24 h and 72 h after irradiation. No significant difference was found in steepness of the erythema dose-response curve for the two lamps at 24 or 72 h. Persistence of erythema was assessed as the percentage of erythema remaining at 72 h. The mean persistence was 63% for narrow-band and 64% for broad-band lamps (p = 0.94). Therefore, in terms of erythemal response, no evidence has been found for a difference in burning potential for the two lamps.


Assuntos
Eritema/etiologia , Lesões por Radiação , Raios Ultravioleta , Adulto , Relação Dose-Resposta à Radiação , Eritema/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Tempo
17.
J Invest Dermatol ; 91(5): 454-7, 1988 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-3171220

RESUMO

The time course of ultraviolet erythema was measured using six different exposure doses of UVC and UVB radiation in each of eight adult subjects. The intensity of erythema was measured by reflectance spectrophotometry at 4, 8, 24, 36, and 48 h after irradiation. In five subjects there was no significant difference between the form of the UVB and UVC erythema time-course. In three subjects a significant difference was observed, but this was random rather than systematic between subjects. The results do not confirm the previously reported major differences in time course between the two qualities of radiation.


Assuntos
Eritema/etiologia , Raios Ultravioleta/efeitos adversos , Adulto , Relação Dose-Resposta à Radiação , Feminino , Humanos , Masculino , Estatística como Assunto , Fatores de Tempo
18.
J Invest Dermatol ; 116(5): 813-5, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11348476

RESUMO

There is considerable interindividual variation in bioavailability of Methoxsalen (8-methoxypsoralen) after ingestion of the standard dose used in photochemotherapy (psoralen plus ultraviolet A). A dose change may be used to alter the degree of photosensitivity, although there is limited information on the effect of 8-methoxypsoralen dose alterations on phototoxicity within individuals. We studied the effect of changes of 8-methoxypsoralen dose over a narrow range in 15 subjects with psoriasis. Two hours after ingestion, serum 8-methoxypsoralen concentration was determined and phototesting was performed at 350 +/- 30 nm (0.45-14 J per cm2). The minimal phototoxic dose at 72 h was recorded, erythema was measured using a reflectance instrument, and dose-response curves were constructed. Each subject was tested on three occasions using doses of 25 mg per m2 (conventional dose) or conventional dose +/- 10 mg. Median serum 8-methoxypsoralen concentration increased from 96 to 143 to 229 ng per ml with dose increases from conventional dose - 10 mg to conventional dose and conventional dose + 10 mg, respectively (p < 0.001). The median minimal phototoxic dose and D0.025 (the objective equivalent of the minimal phototoxic dose derived from the dose-response curve) were significantly reduced with increasing 8-methoxypsoralen dose from conventional dose minus 10 mg (minimal phototoxic dose 1.7 J per cm2; D(0.025) 2.8 J per cm2) to conventional dose (1.2; 1.4 J per cm2) and conventional dose plus 10 mg (0.9; 1.0 J per cm2) (p < 0.001). Change in 8-methoxypsoralen dose had no detectable effect on the maximum slope of the psoralen plus ultraviolet A erythema dose-response curve. Thus, 8-methoxypsoralen dose changes within individuals, over a narrow but clinically relevant range, significantly altered the threshold response to psoralen plus ultraviolet A erythema but not the rate of increase in erythema with increasing ultraviolet A dose.


Assuntos
Eritema/tratamento farmacológico , Eritema/etiologia , Metoxaleno/administração & dosagem , Terapia PUVA/efeitos adversos , Raios Ultravioleta/efeitos adversos , Adulto , Idoso , Relação Dose-Resposta a Droga , Relação Dose-Resposta à Radiação , Eritema/sangue , Humanos , Metoxaleno/sangue , Metoxaleno/uso terapêutico , Pessoa de Meia-Idade , Concentração Osmolar
19.
J Invest Dermatol ; 103(4): 493-9, 1994 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-7930673

RESUMO

The mechanisms mediating the varied effects of ultraviolet radiation (UVR) on human skin are unclear, although a relationship between erythema and DNA damage is suggested by photosensitivity in xeroderma pigmentosum. Increased p53 expression in response to UVR is thought to reflect direct DNA damage, but recent evidence indicates that UVR also activates membrane and cytosolic signal transduction pathways. In this study, we have investigated the relationship between erythema and p53 induction following UVB and whether this p53 response is specific to UVR. p53 protein expression was determined by immunocytochemistry using the monoclonal antibody DO7, and p53 mRNA expression was examined by non-isotopic in situ hybridization. Incremental doses of UVB were administered to the lower back of eight subjects. Immunostaining revealed that p53 positive nuclei were significantly increased 8 h after suberythemogenic doses of UVB (79 +/- 12), compared to normal unirradiated skin (8 +/- 6, p < 0.0005), but no change in p53 mRNA was seen. Higher UVB doses, which resulted in moderate erythema, resulted in a similar or greater induction of p53 protein. Indomethacin (1% w/v), applied immediately after UVB irradiation, significantly inhibited UVB erythema at 8 h in six subjects (p < 0.005), but did not reduce p53 immunostaining. Dithranol (1 microgram/microliter, n = 8), sodium dodecylsulphate (5%, n = 4), and retinoic acid (0.5%, n = 4), applied for 48 h, caused erythema, significantly increased p53 protein levels (p < 0.05), and also increased p53 mRNA. Our results show that in human skin, UVB-induced p53 elevation can be dissociated from erythema and skin irritants can also induce p53 protein. The induction of p53 mRNA by irritants but not UVR suggests different mechanisms of action.


Assuntos
Dermatite Irritante/fisiopatologia , Eritema/metabolismo , Pele/química , Pele/efeitos da radiação , Proteína Supressora de Tumor p53/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Antralina/farmacologia , Eritema/etiologia , Feminino , Regulação da Expressão Gênica , Humanos , Indometacina/farmacologia , Masculino , Pessoa de Meia-Idade , RNA Mensageiro/análise , Transdução de Sinais , Pele/efeitos dos fármacos , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/efeitos da radiação , Raios Ultravioleta/efeitos adversos
20.
Arch Dermatol ; 125(12): 1653-7, 1989 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-2589859

RESUMO

Twenty patients with psoriasis were phototested to determine their erythemal responses to UVB and psoralen-UVA (PUVA) (oral 8-methoxypsoralen). The smallest ultraviolet radiation doses to produce erythema (minimal erythema dose and minimal phototoxic dose, respectively) were recorded and dose-response curves were constructed for UVB (24 hours after irradiation) and PUVA (48 hours) using objective measurement. The choice of a 48-hour measurement was validated by phototesting an additional 11 subjects to determine the time course of PUVA erythema. No correlation was demonstrated between minimal erythema dose for UVB, minimal phototoxic dose for PUVA, and sun-reactive skin type. The mean slope of the dose-response curve for UVB erythema was four times steeper than that for PUVA. Psoralen-UVA erythema reached a broad maximum between 48 and 96 hours after irradiation. Using objective methods we have demonstrated that the commonly accepted view of a steep dose-response relationship for PUVA erythema is not valid.


Assuntos
Terapia PUVA , Transtornos de Fotossensibilidade/etiologia , Psoríase/tratamento farmacológico , Adulto , Idoso , Relação Dose-Resposta à Radiação , Humanos , Metoxaleno/uso terapêutico , Pessoa de Meia-Idade , Dosagem Radioterapêutica , Raios Ultravioleta
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA