Biomedical subjects

E Snellman

Publications and source records attributed to E Snellman.

22 records · Page 2Linked to original sources

PubMed1992

Effect of psoriasis heliotherapy on epidermal urocanic acid isomer concentrations.

A noninvasive Finn Chamber sampling method and HPLC analysis were used to determine epidermal urocanic acid (UCA) concentrations of psoriasis patients during 4 weeks of heliotherapy on the Spanish Canary Islands and a follow-up period of 8 weeks. During heliotherapy the epidermal cis-UCA concentration increased from a mean initial value of 0.2 nmol/cm2 to a mean final value of 2.9 nmol/cm2. The total UCA concentration decreased during the first week of heliotherapy from an initial value of 5.5 nmol/cm2 to a nadir of 2.0 nmol/cm2. Thereafter, a steady increase was recorded in the total UCA level, with a maximum of 10.2 nmol/cm2 in week 2 of the post-treatment follow-up period. Suberythemal sun exposures caused near-maximal UCA isomerization, and during heliotherapy the cis isomer constituted 63.7-74.3% of the total UCA concentration. Clinical response of psoriasis to heliotherapy, however, seemed to be independent of UCA isomer levels.

Adult↗

PubMed1992

Solar ultraviolet (UV) radiation and UV doses received by patients during four-week climate therapy periods in the Canary Islands.

The ultraviolet (UV) radiation doses received by 270 psoriasis patients were studied during 4-week climate therapy periods in November, March or April in the Canary Islands. The daily total solar UV radiation (ambient radiation load, ARL) was measured using frequent readings with a Robertson-Berger sunburning ultraviolet (SUV) meter. A daily personal radiation load (PRL) was calculated for each patient, using sun exposure diary data. To measure the cumulative UV exposure of particular skin sites (skin site dose, SSD), 10 patients wore polysulphone UV dosimeters. The daily ambient radiation load (ARL) ranged from 2.9 to 8.9 erythemal units (EU); the cumulative ARL for a 4-week treatment period was 182.6 EU. The mean daily personal radiation load (PRL), calculated separately for each week of the treatment period, was from 2.5 to 5.6 EU; the mean total 4-week PRL was 118.0 EU, being about 65% of the ARL. The 4-week cumulative skin site dose (SSD) varied between 22.2 and 63.3% (mean 41.2%) of the corresponding personal radiation load (PRL).

Adolescent↗

PubMed1992

Comparison of the antipsoriatic efficacy of heliotherapy and ultraviolet B: a cross-over study.

Ten psoriasis patients who underwent a 4-week heliotherapy period in the Canary Islands were treated with ultraviolet B (UVB) phototherapy at relapse, 2-24 months later. In both settings, psoriasis improvement was monitored using a psoriasis severity index (PSI), and UV exposure was recorded with polysulphone films. In the 8 patients that could be evaluated, a median healing rate of 94% was recorded in the heliotherapy period, with a median cumulative UV dose of 46 erythemal units (EU). In the UVB phototherapy, a median improvement rate of 86% was found after a median cumulative UV dose of 112 EU. It is concluded that, on an erythemal UV dose basis, heliotherapy was more effective than UVB phototherapy in treating psoriasis.

Adult↗

PubMedDate not supplied

Kinetics of phototoxicity in trioxysalen bath psoralen plus ultraviolet A photochemotherapy.

A trioxysalen bath is a safe alternative to systemic 8-methoxypsoralen in long-term psoralen plus ultraviolet A (PUVA) treatment. The kinetics of its main side-effect, the strong phototoxicity, has not been thoroughly studied. This study determined the degree and persistence of phototoxicity after a single 10 min bath at a trioxysalen concentration of 0.33 mg/l. The buttock skin of 16 healthy volunteers was irradiated with UVA 10 min, and 1, 3, 9 and 24h after the bath. The minimal phototoxic dose (MPD) was assessed 48, 72 and 96h after the bath. In general, the 96 h reading showed the lowest values of MPD; for example, a median of 0.14 J/cm2 (95% confidence interval 0.10-0.14 J/cm2) at sites irradiated 10 min after the bath. The values increased progressively with later irradiation, and the maximum dose applied, 18.32 J/cm2, failed to produce any redness when irradiation was given 24 h after the bath. Substantial phototoxicity persists up to at least 9h after the trioxysalen bath, making it wise for patients to avoid sunshine for at least the rest of the day.

Adult↗