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Biomedical subjects

R Roelandts

Publications and source records attributed to R Roelandts.

At least 19 recordsLinked to original sources
PubMed2006

Economic evaluation of methyl aminolaevulinate-based photodynamic therapy in the management of actinic keratosis and basal cell carcinoma.

BACKGROUND: Various effective therapeutic options are currently available for the treatment of actinic keratosis (AK) and basal cell carcinoma (BCC), but none is perfect. Poor cosmesis resulting from surgical procedures and skin irritation induced by topical agents remain significant problems. OBJECTIVES: To evaluate the cost-effectiveness of a recent approach, methyl aminolaevulinate-based photodynamic therapy (MAL-PDT; Metvix; Galderma, Lausanne, Switzerland) in AK and BCC. METHODS: A medical decision tree was developed for simulation of all possible outcomes associated with the medical decision to apply MAL-PDT or a comparator. The time horizon was 1 year for AK and 5 years for BCC. The comparators were cryotherapy in AK and excision surgery in BCC. Clinical data for the model were obtained from the literature. Data on medical management resulted from a Delphi panel performed among 12 Belgian dermatologists. Based on the model, the cost per full responder was calculated, whereby a responder was defined as a patient with all lesions clinically responding and showing an excellent cosmetic result. RESULTS: MAL-PDT is a more expensive treatment compared with cryotherapy for AK. However, the cost per full responder is comparable with cryotherapy (euro363 and euro379, respectively). Incremental cost per extra full responder is euro401. Incremental cost per full responder is euro469 for nodular BCC and euro251 for superficial BCC, both compared with excision surgery. CONCLUSIONS: The results suggest that MAL-PDT is a cost-effective intervention in AK taking a 1-year time horizon, if society is willing to pay euro1.50 per day of response, and that MAL-PDT is better value for money than excision in BCC, taking a 5-year time horizon.

Aminolevulinic Acid↗
PubMed2002

Long-term efficacy and safety of tacalcitol ointment in patients with chronic plaque psoriasis.

BACKGROUND: As psoriasis patients often require continuous treatment optimal therapy has to provide efficacy and a good safety profile over the long term. OBJECTIVES: The aim of this multicentre study was to assess the efficacy, safety and tolerability of tacalcitol (4 microg g(-1)) ointment (Curatoderm, Hermal, Reinbek, Germany) applied once daily over a treatment period of 18 months. PATIENTS AND METHODS: Efficacy parameters were Psoriasis Area Severity Index (PASI), based on summed scores of erythema, infiltration and scaling and total body surface involvement (TBI). Safety assessment included serum levels of calcium, parathyroid hormone, calcitonin, 1,25-dihydroxy vitamin D3 (calcitriol); urinary calcium, creatinine, calcium/creatinine ratio in spot and 24-h urine and urinary alpha(1)-microglobulin. A group of 304 patients with chronic plaque psoriasis, covering between 7% and 20% of the body surface area was included for the initial treatment phase of 3 months. Of the 257 patients who completed the initial 3 months, 197 patients continued in a second treatment phase of 15 months. RESULTS: Tacalcitol treatment proved to be effective in reducing the severity of psoriasis and maintained therapeutic response over the study period. The median PASI fell from 9.5 to 4 .6 at month 3 and to 3.25 at month 18 (P < 0.0001). The median improvement in TBI was 30% at month 3 and 50% at month 18. In no patient was there any relevant disturbance of calcium homeostasis. There were no significant changes in mean values of serum calcium, parathyroid hormone and calcitriol. Additionally no significant changes in 24-h urinary excretion evaluation were observed. There was no correlation between levels of serum calcium or urinary calcium and amount of tacalcitol ointment used, even in the patients requiring the largest amounts of ointment (up to 13 g day(-1) and up to 20% of body area affected). Treatment was generally well tolerated and there were no serious or unexpected adverse events reported. However, discontinuation of treatment as a result of skin irritation was seen in 5.9% of patients. The greatest frequency of cutaneous side-effects occurred during initial treatment and the incidence decreased markedly as the treatment was well-tolerated with continued use. CONCLUSIONS: Tacalcitol ointment once daily was demonstrated to be efficacious, safe and well tolerated in the long-term control of plaque psoriasis in patients with up to 20% body surface involvement.

Adolescent↗
PubMed2000

The diagnosis of photosensitivity.

Many photosensitive patients are seen for consultation when they have no lesions, so a detailed history is important. The differential diagnosis is based on the age at which the symptoms first occurred. The striking symptoms and signs are discussed, and advice is given on which additional investigations are necessary and when phototesting must be performed. Guidelines are also given for the performance of phototesting with simple light sources.

Adolescent↗
PubMed1999

Photo(chemo)therapy in private practice in Belgium, France and The Netherlands.

Photo(chemo)therapy is used widely, and ultraviolet (UV) sources, protocols and indications are numerous. A survey was carried out to examine how photo(chemo)therapy is employed in private practice and to determine whether safety guidelines are respected. A questionnaire survey sent to Belgian, French and Dutch dermatologists generated 593 useful responses. UV sources, doses of UV and 8-methoxypsoralen (8-MOP), as well as the frequency of the treatment, were all different in the three countries. UV starting doses were rarely chosen according to the minimal phototoxic dose (MPD) or to the minimal erythema dose (MED). Total cumulative UV doses were not always determined. Maintenance PUVA therapy for psoriasis was still performed by 15 to 40% of dermatologists in the respective countries. Another striking fact was that genital protection is not universal. On the other hand, the irradiance of tubes is checked regularly, and contraindications are respected. Despite the availability of guidelines, clinicians seem to be inconstant in their assessment of the carcinogenic risk of UV radiation.

Belgium↗
PubMed1998

Solar urticaria. A report of 25 cases and difficulties in phototesting.

BACKGROUND: Solar urticaria is a rare photosensitive disease, and its differential diagnosis with respect to polymorphous light eruption is sometimes difficult. We report our experience with 25 cases of solar urticaria and discuss the pitfalls in phototesting such patients. OBSERVATION: The most important locations in this patient series are the V of the neck and the arms, which are similar to those of polymorphous light eruption. In all of the patients, however, the lesions appeared within 30 minutes of sun exposure or phototesting and disappeared within 24 hours. Notably, 12 (48%) of the patients had a history of atopy. Phototesting helps confirm the diagnosis, but, in some patients, this was difficult. CONCLUSIONS: A negative phototest result from a single light source does not necessarily exclude a diagnosis of solar urticaria. In patients in whom phototesting elicits negative reactions, other light sources should be used, and, if the phototest result is still negative, a provocative test with natural sunlight should be done. Histamine1-receptor antihistamines are a useful first-line therapy, although more severely affected persons may require prophylactic courses of phototherapy or photochemotherapy. The main problem is maintenance treatment.

Adolescent↗
PubMed1995

Photo(chemo)therapy and general management of erythropoietic protoporphyria.

Erythropoietic protoporphyria is an autosomal dominant or autosomal recessive photodermatosis characterized by a deficiency of the enzyme ferrochelatase. The diagnosis is based on the very typical complaints of burning and pain on sun exposure and on increased protoporphyrin concentration in the red blood cells, the plasma and the feces. Different treatment modalities have been proposed. The treatment of choice has always been beta-carotene. For severe cases, PUVA treatment can be given three times a week until a total UVA dose of 120-200 J/cm2. In younger children, UVB phototherapy can be used if beta-carotene gives unsatisfactory therapeutic results. The irradiations are given four times a week until a total dose of 1-1.5 J/cm2 is reached.

Adolescent↗
PubMed1993

Chronic actinic dermatitis.

Chronic actinic dermatitis (CAD) is one of the most frequently encountered photodermatoses in patients older than 50 years of age. It is characterized by persistent redness of the face and other exposed areas. CAD can become so severe that even nonexposed parts of the body develop eczematous lesions and the disease persists during winter. The diagnosis must be confirmed by phototests that show a broad action spectrum with low threshold doses. CAD must be differentiated from photocontact allergy and airborne dermatitis. The histopathologic features in the early stages are comparable to contact dermatitis, whereas in the later stages they may be those of pseudolymphoma. The most popular treatments are azathioprine and PUVA.

Chronic Disease↗
PubMed1992

Evaluating the UVA photoprotection of sunscreens with murine skin edema.

The acute and chronic deleterious effects of UVA on skin have prompted a growing interest in developing effective UVA-photoprotective sunscreens. The quantification of their UVA photoprotection remains, however, a major problem. In the present study, murine skin edema induced by 8-methoxypsoralen plus UVA (PUVA) is evaluated as a screening method for quantifying the UVA photoprotection of commercially available sunscreens. The PUVA-induced murine skin edema is provoked on the dorsa of female hairless albino mice and measured with a hand-held micrometer. A clear time course and a well-defined dose-response relationship are demonstrated. Therefore, a UVA-photoprotection factor (UVA-PF) could be defined by dividing the minimal edema dose with sunscreen by the minimal edema dose without sunscreen. The UVA-PF values obtained with this method were quantitatively and qualitatively very similar to those obtained in 8-methoxypsoralen-photosensitized murine skin by using the number of sunburn cells as the biologic end point and were qualitatively similar to UVA-PF values obtained in human skin using phototoxic erythema and UVASUN-induced tanning as the parameter. It is concluded that PUVA-induced murine skin edema offers an objective, reproducible, and easily applicable screening method for quantifying the degree of UVA photoprotection of a sunscreen.

Animals↗
PubMed1992

The relative importance of the components used for ultraviolet A protection in broad-spectrum sunscreens.

The need for effective ultraviolet A (UVA) protection is increasing. Broad-spectrum sunscreens are being used to protect the skin against aging and in the treatment of photodermatoses, where UVA protection can be vital. They are also used by patients taking photosensitizing drugs, such as 8-methoxypsoralen, to protect their skin against solar UVA. This raises the question of what components in broad-spectrum sunscreens are the most necessary for optimal UVA protection. In the present study, the components that can be used are compared and evaluated using an animal method with the inhibition of skin edema induced by 8-methoxypsoralen plus UVA as the biological end point. The results of this method indicate that powders do not provide any significant UVA protection. This could be due to the use of 8-methoxypsoralen in the test so that particularly the shorter UVA range is evaluated. Powders reflect mainly the longer UVA wavelengths. The UVA protection as measured with this method seems to be similar for the benzophenone derivative and for the dibenzoylmethane derivative. The UVA protection factors obtained are compared with those obtained in human skin using phototoxic erythema and UVA-induced tanning as parameters.

Animals↗
PubMed1991

Which components in broad-spectrum sunscreens are most necessary for adequate UVA protection?

There is an increasing need for broad-spectrum sunscreens that afford adequate UVA protection. In the selection of such a sunscreen, the sun protection factor is of no real value because it gives an indication of only the UVB protection. As long as the methods used to determine the real UVA protection factor are not standardized, the most valid information is the formula of the sunscreen. To determine the components that are most necessary for optimal UVA protection, different components were compared separately and in combination in human subjects by different methods. The physical agents tested gave only relatively weak UVA protection in both the shorter and the longer UVA ranges. Dibenzoylmethane derivatives are more efficient than the physical agents, but only in the shorter UVA range. The UVA protection afforded by the combination of a dibenzoylmethane derivative and physical agents appears to be cumulative.

Adult↗
PubMed1991

The history of photochemotherapy.

The combination of psoralens, obtained from plants, and sun exposure dates from antiquity. The main indication was vitiligo. In this century, extensive research on psoralens started in Egypt, where the active ingredients were isolated from plants and were soon thereafter commercialized for the treatment of vitiligo. The most important compound was 8-methoxypsoralen. When it was discovered that 8-methoxypsoralen inhibits the S phase of the cell cycle, it also started to be used in the treatment of psoriasis. In the meantime, the action spectrum was defined in the ultraviolet A (UVA) range (320-400 nm). Special UVA light boxes were constructed for total body irradiation. At first, the 8-methoxypsoralen was applied topically. Within a few years, high-intensity UVA bulbs became available, which permitted the 8-methoxypsoralen to be administered orally. Photochemotherapy or PUVA treatment as we know it today had begun.

History, 20th Century↗
PubMed1990

Protecting the eye from ultraviolet A radiation during photochemotherapy.

Except for the skin, the eye is the only organ that is continuously exposed to solar radiation, including longwave ultraviolet irradiation (UVA). Since 8-methoxypsoralen (8-MOP) remains not only in the skin but also in the lens of the eye after 8-MOP + UVA (PUVA) treatment, wearing protective goggles just during the UVA irradiation is insufficient. It is wise to shield the eyes for several hours after 8-MOP ingestion, to avoid or reduce possible long-term side effects such as cataract formation. Adequate eye protection from UVA after PUVA can be provided by sunglasses that filter out the appropriate UVA spectrum from the sunlight. Nearly all the commercially available sunglasses are colored, which reduces the intensity of the visible light reaching the eye. In such cases, the diameter of the pupil can remain dilated, which it would not without sunglasses. However, the UVA intensity remains the same. As a result, more UVA can reach the lens. In this study, new uncolored glasses are evaluated and compared with commercially available sunglasses (all colored) to determine their UVA transmission.

Eye↗
PubMed1989

Evaluating the UVA protection of sunscreens.

Because the protection factor of sunscreens concerns only UVB protection, usually nothing is known about the protection offered in the UVA range. Using different methods, we compared six commercially available sunscreens to determine the UVA protection factor and, thus, to select the most appropriate sunscreen. Two clinical methods on human skin (inhibition of UVA-induced tanning with the use of a high-intensity UVA source and inhibition of methoxsalen plus UVA-induced phototoxicity) were compared with a method in animals (inhibition of UVA-induced sunburn cell production in mice treated with methoxsalen) and with two in vitro techniques (solution-dilution and sandwich spectrophotometry). We conclude that all five methods used give a quantitative estimate of UVA protection, but none can be accepted as a standard because the UVA protection factor varies according to the method used and the reading time.

Adolescent↗