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Biomedical subjects

R S Dawe

Publications and source records attributed to R S Dawe.

At least 19 recordsLinked to original sources
PubMed2006

Regulation of cutaneous drug-metabolizing enzymes and cytoprotective gene expression by topical drugs in human skin in vivo.

BACKGROUND: Individuality in the expression and regulation of hepatic drug-metabolizing enzymes (DMEs) and cytoprotective (CP) genes is an important determinant of treatment response. There is increasing evidence that many DMEs and CP genes are also expressed in human skin. Responses to topical drugs used to treat common skin diseases, such as psoriasis, are unpredictable and may potentially be rationalized, at least in part, by interindividual differences in cutaneous DME and CP gene expression. OBJECTIVES: We investigated whether three topical drugs [coal tar, all-trans retinoic acid (atRA) and clobetasol 17-propionate] used in routine clinical practice modulated the expression of a variety of DME and CP genes [cytochrome P450s, glutathione S-transferases (GSTs) and drug transporters] in healthy human skin in vivo. METHODS: Healthy adult volunteers (n = 30) were invited to participate in the study. Each subject was randomly allocated to receive two of the three study chemicals and one control site application. Crude coal tar (n = 13), atRA (n = 14) or clobetasol 17-propionate (n = 10) was applied under occlusion to photoprotected buttock skin for 96 h. A vehicle control (white soft paraffin) was also applied under the same conditions at an adjacent site in all subjects. Full-thickness punch biopsies (4-mm diameter) were then taken from treated and control sites. Total RNA was extracted and reverse transcribed into cDNA, which was used as a template in subsequent real-time polymerase chain reaction analysis, where fluorescent output was directly proportional to input cDNA concentration. Triplicate measurements of skin mRNA expression were made from each sample, and the arithmetic mean values taken. After logarithmic transformation, the paired t-test was used to compare values between treated and control skin. RESULTS: Cytochrome P450s CYP1A1, CYP1A2, CYP1B1, CYP2C18, quinone reductase (NQO-1), GSTP1, gamma-glutamyl cysteine synthetase (gamma-GCS), glutathione peroxidase-1 (GPx-1), cyclooxygenase-2 (COX-2) and haem oxygenase-1 (HO-1) were induced by coal tar; CYP26, NADPH P450 reductase (CPR), GSTP1 and HO-1 by atRA; and CYP3A5 by clobetasol 17-propionate. In contrast, CYP1A1 and CYP1A2 expression was suppressed by atRA, and gamma-GCS and MRP1 by clobetasol 17-propionate. Marked interindividual variation in gene regulation by topical drugs was seen for the majority of genes examined. CONCLUSIONS: These data demonstrate that topical drugs can modulate DME gene expression in human skin in vivo and indicate that variation in the expression and regulation of these genes may be a determinant of individuality in response to topical therapies for common skin diseases.

Administration, Cutaneous↗
PubMed2006

UVA1 phototherapy for treatment of necrobiosis lipoidica.

The primary cause of collagen degeneration in necrobiosis lipoidica (NL) is proposed to be immunologically mediated vascular disease. Ultraviolet (UV)A1 has been used successfully to treat scleroderma in which both vascular damage and collagen dysregulation also occur. We treated six patients with NL [(five women; mean age of 32 years (range 22-70) and mean disease duration of 2.9 years (range 6 months to 5 years)] with a high-output ultraviolet (UV)A1 2-kW filtered metal halide source (Dr Hönle; Dermalight ultrA 1) having an emission spectrum of 340-440 nm. All patients had NL on the shins, which had been unresponsive to potent topical corticosteroid therapy (n = 6) and had responded minimally or not at all to TL-01 UVB (n = 2), topical psoralen plus UVA (PUVA) soaking (n = 2) or oral PUVA (n = 1) therapy. Patients received a variable number of total exposures (15-51), given 3-5 times weekly. NL resolved completely in one patient; this patient had minimal improvement after the first course of 16 exposures, but after a further 13 exposures, resolution occurred 6 months later. Two subjects obtained moderate improvement in their overall disease severity after 15 and 24 exposures, while two had only minimal improvement after 15 and 51 exposures. The remaining patient had no improvement after 16 treatments. Patients with the shortest disease duration had the greatest response. UVA1 therapy may be of benefit for the treatment of NL as an adjuvant therapy to topical corticosteroids or as a second-line alternative to other phototherapies, and may have a superior outcome in a proportion of patients.

Adult↗
PubMed2006

UVA1 phototherapy for genital lichen sclerosus.

BACKGROUND: Lichen sclerosus (LS) is characterized histologically by an inflammatory T-cell infiltrate, sclerosis and thickening of the dermis, and epidermal atrophy. Ultraviolet (UV) A1 therapy has been shown to be effective in the management of morphea and scleroderma, diseases that have some histological and clinical similarities with LS, and more recently in extragenital LS. AIM: To determine the effectiveness of UVA1 therapy for genital LS. METHODS: Seven women with severe genital LS uncontrolled by ultrapotent topical corticosteroids, with a median age of 62 years (range 48-78) and disease duration of 6-47 years, were treated with UVA1 therapy from a high output source. After completion of UVA1 therapy, a clinician and the patient graded the overall response of symptoms and physical signs. RESULTS: Five patients improved with therapy. Three obtained moderate improvement in overall disease severity and two had minimal improvement. Of these five, one relapsed within 3 months and another after a year. Both had a further course of UVA1 therapy, resulting in minimal improvement in one and moderate improvement in the other. In the remaining three, disease severity had improved to a point where intermittent use of topical corticosteroids resulted in acceptable control. DISCUSSION: UVA1 therapy may be of benefit in the management of vulval LS, a disease that is often poorly responsive to standard therapies. The therapy is well tolerated and could provide an acceptable therapeutic option for patients with severe disease.

Aged↗
PubMed2005

The photocarcinogenic risk of narrowband UVB (TL-01) phototherapy: early follow-up data.

BACKGROUND: Limited information is available on the carcinogenic risk associated with narrowband TL-01 UVB phototherapy in humans. OBJECTIVES: To determine the skin cancer incidence in a population treated with TL-01 phototherapy. PATIENTS AND METHODS: All TL-01-treated patients were identified from the departmental computerized database. Patients with malignant melanoma (MM), squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) were identified by record linkage with the Scottish Cancer Registry. The incidence of each was compared with the normal Scottish population matched for age and sex. RESULTS: Data were obtained from 1908 patients. The median follow-up duration was 4 years (range 0.04-13). The median cumulative number of TL-01 treatments and dose were 23 (1-199) and 13 337 (30-284 415) mJ cm(-2), respectively. No increased incidence of SCC or MM was observed. Ten patients developed BCC compared with an expected 4.7 in the Scottish population [standardized rate ratio 213 (95% confidence interval 102-391); P < 0.05]. CONCLUSIONS: A small but significant increase of BCC was detected in the TL-01 group. This could be explained by a number of factors, including ascertainment bias. To determine the true carcinogenic risk of TL-01 phototherapy, longer follow-up is essential.

Aged↗
PubMed2005

A randomized controlled comparison of the efficacy of Dead Sea salt balneophototherapy vs. narrowband ultraviolet B monotherapy for chronic plaque psoriasis.

BACKGROUND: Dead Sea (DS) salt solution soaks are used in combination with narrowband ultraviolet B (NB-UVB) to treat psoriasis in many centres, particularly in continental Europe. No previously published controlled study has assessed DS salt + NB-UVB balneophototherapy. OBJECTIVES: To compare DS salt balneophototherapy with NB-UVB monotherapy for chronic plaque psoriasis. METHODS: Sixty patients with chronic plaque psoriasis participated in this paired, controlled study, with pretreatment DS salt soaks randomly allocated to each participant's right or left study limb. Psoriasis severity was assessed with a Scaling, Erythema and Induration score by a blinded observer. Assessments were weekly during the therapy course, and thereafter 8-weekly until relapse or for up to 1 year after clearance. RESULTS: The mean area under the psoriasis severity-time curves during treatment was not detectably lower with DS salt balneophototherapy than with NB-UVB monotherapy (P = 0.099). The psoriasis severity score fell slightly more from beginning to end of courses with DS salt balneophototherapy than with NB-UVB monotherapy (P = 0.019). There was no detectable difference in times to relapse. CONCLUSIONS: In this population the addition of pretreatment DS salt soaks to NB-UVB did not result in a clinically important improvement in clearance of psoriasis.

Adult↗
PubMed2005

Can St John's wort (hypericin) ingestion enhance the erythemal response during high-dose ultraviolet A1 therapy?

BACKGROUND: St John's wort (SJW) is widely used as a treatment for depression. A phototoxic reaction, due to its content of hypericin, can occur in animals and in cell culture, and has been reported in humans. Hypericin displays absorption within the ultraviolet (UV) A1 spectrum and there may therefore be a potential for phototoxicity if taken during high-dose UVA1 therapy. OBJECTIVES: To assess the phototoxicity risk of SJW ingestion. METHODS: Eleven adult volunteers of skin types I and II were exposed to a geometric dose series of UVA1 irradiation from a high-output source (Dermalight Ultra 1; Dr Hönle, Martinsreid, Germany; irradiance 70-77 mW cm(-2)) on the photoprotected lower back skin at eight 1.5-cm(2) test areas. Irradiation was carried out at baseline and after 10 days of SJW extract 1020 mg (equivalent to 3000 microg of hypericin) daily. Four, 8, 24 and 48 h after each exposure, the minimal erythema dose (MED) and the presence or absence of pigmentation were recorded visually and erythema was assessed objectively with an erythema meter. RESULTS: The median MED and D(0.025), an objective measure of MED, were lower at all time-points after SJW ingestion. The visual erythemal peak (lowest median MED), which was seen at 8 h postirradiation, was lower after SJW (median 14 J cm(-2), range 10-56) than at baseline (median 20 J cm(-2), range 14-56) (P = 0.047). Similarly, the median D(0.025) at 8 h postirradiation was lower after SJW (median 22.0 J cm(-2), range 15.2-53.9) than at baseline (median 33.7 J cm(-2), range 22.9-136.0) (P = 0.014). The MED and D(0.025) were also significantly different at the 48-h and 4-h time-points, respectively. Significance was not reached at the 24-h time-point. Median intensity of postirradiation erythema increased at all time-points after ingestion of SJW. Despite these differences, the maximum slope of the dose-response curve was not increased after SJW ingestion. CONCLUSIONS: These data suggest that SJW extract has the potential to lower the erythemal threshold to UVA1 irradiation in a significant proportion of individuals and highlight the importance of ascertaining a full drug history, including herbal remedies, before initiating UVA1 phototherapy.

Adult↗
PubMed2005

Does narrow-band ultraviolet B phototherapy work in atopic dermatitis through a local or a systemic effect?

The likely mechanisms of action of narrow-band ultraviolet B (NB-UVB) in atopic dermatitis are several. We attempted, in a 12 patient prospective intraindividually controlled study, to determine whether the effect of NB-UVB in atopic dermatitis is primarily through systemic or local effects. Change in observer-assessed severity of patches of dermatitis covered during each whole-body NB-UVB treatment was compared with change in uncovered neighbouring patches. We found great variation between patients in responses. Only in two (of 12) patients was there a large difference between directly exposed and covered patch dermatitis severity. We suspect that the balance of local and systemic effects important in determining response to NB-UVB in atopic dermatitis varies from patient to patient. This study did not conclusively answer our original question, but did show that in some patients localized effects of NB-UVB are important.

Case-Control Studies↗
PubMed2004

A randomized, double-blind, placebo-controlled study of the efficacy of tetracaine gel (Ametop) for pain relief during topical photodynamic therapy.

BACKGROUND: Many patients find topical 5-aminolaevulinic acid (ALA) photodynamic therapy (PDT) painful. Local anaesthetics are not routinely used and their effect on PDT pain has not been examined. OBJECTIVES: To evaluate the efficacy of tetracaine gel (Ametop) for pain relief during and after PDT. METHODS: A prospective, double-blind, placebo-controlled study of 42 patients with lesions (< or =2 cm diameter) of superficial nonmelanoma skin cancer or dysplasia. Patients were randomized to either tetracaine (4% w/w) (n=22) or vehicle (n=20) gel under occlusion for 1 h pre-irradiation. Pain was assessed during and after irradiation using a visual analogue scale (VAS) and faces pain scale. RESULTS: Patients who received tetracaine gel experienced only slightly less pain during PDT (median VAS 4) compared with those who received placebo (median VAS 4.5) (95% confidence interval for difference 0-3, P=0.08). No significant difference in pain was experienced between the treatment groups immediately after irradiation or later. CONCLUSIONS: When compared with placebo, tetracaine gel did not significantly reduce pain during or after PDT for small lesions of superficial basal cell carcinoma, Bowen's disease or actinic keratosis.

Administration, Topical↗
PubMed2004

A pilot study of treatment of lentigo maligna with 5% imiquimod cream.

BACKGROUND: Lentigo maligna (LM) is an in situ form of malignant melanoma, and surgical excision is often unsatisfactory. Imiquimod cream is an immune response modifier and induces a predominantly T-helper 1 type response. OBJECTIVES: Assessment of histological and clinical response of surgically resectable LM after treatment with 5% imiquimod cream. METHODS: Six patients with LM were treated with 5% imiquimod cream daily for 6 weeks. The whole site of the original lesion was then excised. Clinical and histological and appearances were measured using clinical response and histological grading scores. RESULTS: Complete or almost complete clearance of pigmentation with minimal residual histological evidence of LM was observed in four patients, one patient showed no clinical or histological improvement, and the remaining patient had almost no residual pigmentation clinically after treatment yet histopathological changes remained as severe as before treatment. CONCLUSIONS: Topical imiquimod cream merits further investigation as a new therapy for LM.

Administration, Topical↗
PubMed2004

The optimal time to determine the minimal phototoxic dose in skin photosensitized by topical 8 methoxypsoralen.

BACKGROUND: We recently investigated the characteristics of psoralen plus ultraviolet (UV) A erythema in skin photosensitized by topical 8-methoxypsoralen (8-MOP) in three independent studies. OBJECTIVES: In order to determine the optimal time to read the minimal phototoxic dose (MPD) after treatment with topical 8-MOP and irradiation with UVA, we assessed the overall data. METHODS: One forearm of each subject was immersed in 8-MOP solution for 15 min and test sites on the flexor surface of the forearm were immediately exposed to a UVA dose series. Erythema was assessed visually and objectively using a reflectance instrument at 24-h intervals for 7 days. RESULTS: Results were obtained from 44 subjects (predominantly Fitzpatrick skin phototype II). A broad erythemal plateau was evident beyond 72 h and the visual MPD was significantly lower at 96, 120 and 144 h than at 72 h (P < 0.01). Only 30% of subjects were at peak erythema at the conventional MPD assessment time of 72 h. The median time to reach maximal erythema was 96 h (range 48-144). Objectively, 85% of subjects were at peak erythema at or beyond 96 h. CONCLUSIONS: We recommend that (i) the optimal time to read the topical 8-MOP MPD is 4 days after UVA exposure as readings beyond this time may be difficult to interpret because of the development of pigmentation, and (ii) 40% of the topical 8-MOP MPD should be considered for the first treatment.

Adult↗
PubMed2004

An update and guidance on narrowband ultraviolet B phototherapy: a British Photodermatology Group Workshop Report.

Summary These guidelines for use of narrowband (TL-01) ultraviolet B have been prepared for dermatologists by the British Photodermatology Group on behalf of the British Association of Dermatologists. They present evidence-based guidance for treatment of patients with a variety of dermatoses and photodermatoses, with identification of the strength of evidence available at the time of preparation of the guidelines, and a brief overview of background photobiology.

Combined Modality Therapy↗
PubMed2004

History of psoriasis response to sunlight does not predict outcome of UVB phototherapy.

We prospectively asked 146 consecutive patients starting narrow-band UVB (NB-UVB) for psoriasis about the effects of sunlight on their psoriasis. Eighty-eight (60%) patients reported improvement with sunlight, six (4%) reported worsening, and 52 (36%) had not noted any change in their psoriasis with sunlight exposure. Overall, 101 (69%) were recorded to reach clearance or minimal residual activity (MRA), 24 (16.5%) to achieve moderate improvement, and 21 (14.5%) had other recorded outcomes (mainly 'did not attend'), with UVB phototherapy. Forty-two (72%) of the 58 who did not report improvement with sunlight went on to clearance/MRA with UVB compared to 59/88 (67%) of those who did report improvement (95% confidence interval for difference in percentage improving, -10% to 20%, P = 0.49). Patients' replies to questions about how their psoriasis responds to sunlight do not appear to predict response to UVB phototherapy in our patient population.

Adolescent↗