Search PubMed⌕ Search

Biomedical subjects

N J Lowe

Publications and source records attributed to N J Lowe.

At least 91 records · Page 5Linked to original sources
PubMed1988

New retinoids for dermatologic diseases. Uses and toxicity.

Systemic administration of retinoids is frequently associated with mucocutaneous side effects, liver toxicity, and abnormalities of the serum lipid profile. Currently, the main factors limiting more common use of retinoids are their teratogenicity and chronic bone toxicity. Treatment with retinoids requires appropriate selection of patients, careful periodic monitoring of the clinical response, and appropriate laboratory tests. Careful therapeutic management is necessary in order to prevent or minimize side effects.

Acne Vulgaris↗
PubMed1988

Psoriasis.

Explore the source record for details and available documents.

Adolescent↗
PubMed1987

Comparative efficacy of two dosage forms of oral methoxsalen in psoralens plus ultraviolet A therapy of psoriasis.

Two alternate oral formulations of 8-methoxypsoralen, one liquid and the other crystalline, were evaluated in a double-blind trial for their comparative efficacy in combination with ultraviolet A (UVA) light in the treatment of severe psoriasis. With the liquid formulation a greater proportion of patients achieved a good clinical result within the 20 treatment sessions than patients receiving the crystalline formulation. This difference is even more striking using a more rigorous criterion of clearance. Among all patients who achieved clearance, no significant differences were seen in either the number of treatments required or in the total UVA energy employed between the two groups. The preceding clinical results are discussed in light of published pharmacokinetic data.

Administration, Oral↗
PubMed1987

Actinic reticuloid in a black man: successful therapy with azathioprine.

A 61-year-old black man suffering from actinic reticuloid with contact allergy to four substances, extreme sensitivity to both ultraviolet A and ultraviolet B, normal visible light sensitivity, and negative results on photopatch tests was placed on a regimen of azathioprine, 50 mg twice a day. At 3 months, clinical appearance was unchanged, as was his strong contact allergy; however, tolerance to natural sunlight was markedly improved. At 6 months the clinical appearance and ultraviolet responses were normal; however, strong contact allergy persisted. To our knowledge, this is the first report of actinic reticuloid in a black person. Azathioprine, after giving an excellent clinical response without leukopenia, was discontinued. A further 9-month follow-up showed continued remission. The persistence of contact allergy, despite profound improvement in photosensitivity and the skin's appearance, suggests that the role of contact allergy in the cause of actinic reticuloid is unclear, and the existence and identity of the hypothesized photosensitizer(s) in actinic reticuloid remain unproved.

Azathioprine↗
PubMed1987

Indoor and outdoor efficacy testing of a broad-spectrum sunscreen against ultraviolet A radiation in psoralen-sensitized subjects.

The efficacy of a sunscreen containing an investigational drug, butyl methoxydibenzoylmethane in combination with padimate O against the erythemogenic effect of ultraviolet A (UVA) radiation was evaluated in two double-blind studies involving subjects sensitized with topical 8-methoxypsoralen. UVA radiation was supplied from either a filtered solar simulator (indoors) or filtered sunlight (outdoors). Five formulations were tested: 3% butyl methoxydibenzoylmethane and 7% padimate O, 7% padimate O, 5% octyl salicylate, and 3% oxybenzone, 3% butyl methoxydibenzoylmethane alone, 7% padimate O alone, and vehicle. Sunscreen protection against the erythemogenic effect of UVA radiation was expressed as phototoxic protection factors. The phototoxic protection factor for each sunscreen was derived from a ratio of the minimal phototoxic dose of UVA radiation that produced delayed erythema on sunscreen-protected and unprotected skin. The combination of 3% butyl methoxydibenzoylmethane and 7% padimate O provided significantly greater protection than the other sunscreen formulations, and for each sunscreen the phototoxic protection factors determined indoors and outdoors were comparable.

4-Aminobenzoic Acid↗
PubMed1987

Etretin therapy for severe psoriasis. Evaluation of initial clinical responses.

We have investigated the clinical responses of 21 patients with severe psoriasis to therapy with etretin, a metabolite of etretinate. In a preliminary double-blind dose-finding study, the optimum dose of etretin was determined to be 50 mg/d (mean, 0.66 mg/kg/d). In an open study, patients receiving etretin therapy were followed up for a minimum of six months. An excellent or good response (greater than 50% clearance) was obtained in 18 of 21 patients. The incidence of mucocutaneous side effects from etretin therapy was similar to that previously reported with etretinate therapy. As a group, patients who received etretin therapy for six or more months showed no significant aberrations from normal levels of serum lipids or serum liver enzymes. However, five patients had mild elevation of liver enzymes or blood lipids, which were corrected by dose reduction. Etretin showed equivalent efficacy to that previously reported with etretinate in severe recalcitrant plaque psoriasis vulgaris. Taken with the reportedly more rapid clearance of etretin from the body, there may be clinical advantages of the use of etretin over the use of etretinate.

Acitretin↗
PubMed1987

Short-contact anthralin therapy for psoriasis using an aqueous cream formulation.

A pilot study of five patients was conducted using an aqueous anthralin cream (Drithocreme) and demonstrated that between twenty and forty minutes was an effective contact time to produce an improvement in induration of psoriatic plaques. In a further, bilateral controlled study, the anthralin cream was used to treat twenty patients with symmetrical chronic plaque psoriasis. The cream was applied to one side of the body overnight and then to the other side in the morning. Thirty minutes later it was washed off both sides in a bath or shower. The results indicated that both overnight and short-contact treatment were equally effective, and the short-contact treatment reduced staining and irritation.

Adult↗
PubMed1986

all-trans-Retinoic acid inhibits the appearance of two phorbol ester-induced ornithine decarboxylase mRNAs in mouse epidermis.

Two ornithine decarboxylase mRNA species are seen in mouse epidermis in response to the topical application of the phorbol ester tumor promoter, 12-O-tetradecanoyl phorbol-13-acetate (TPA). This induction occurs in a time- and dose-dependent fashion and appears to be relatively specific as alpha-actin mRNA reveals no change with treatment. Both mRNA species are inhibited in a dose-dependent manner by treating mouse skin with all-trans-retinoic acid prior to TPA. These results indicate that these two compounds are active at the transcriptional level.

Animals↗
PubMed1986

PUVA therapy for psoriasis: comparison of oral and bath-water delivery of 8-methoxypsoralen.

A direct clinical comparison has been made of the efficacy of oral 8-methoxypsoralen with bath-water delivery of 8-methoxypsoralen during psoralen ultraviolet A (PUVA) phototherapy for a group of forty patients with stable plaque-type psoriasis vulgaris. The 8-methoxypsoralen concentration was 3.7 mg/liter in the bath water. The efficacy of these treatments was assessed by their ability to improve or clear the psoriasis. The skin of eight of the twenty patients with oral psoralen cleared, and another eight showed good improvement. Of the twenty patients who received 8-methoxypsoralen in bath water, eight patients had clearing of the skin, whereas nine patients had good improvement during the initial 8-week treatment period. Administration of 8-methoxypsoralen in bath water required much lower ultraviolet A irradiance to achieve maximum improvement. There were no systemic side effects in the patients treated by bath-water delivery; however, some patients did develop phototoxic erythema. Minimal phototoxic doses were also studied in patients and in volunteers using both routes of psoralen delivery. The minimal phototoxic dose threshold after psoralen bath delivery gradually declined over five treatments from 5.3 +/- 0.6 joules/cm2 to 2.8 +/- 0.3 joules/cm2, suggesting an accumulation of psoralen in the skin with this method of drug delivery. Bath-water delivery of 8-methoxypsoralen was therefore found to be as effective as oral administration of 8-methoxypsoralen and yet required smaller amounts of ultraviolet A radiation and yielded fewer side effects. It would thus seem to be confirmed as a useful alternative means of 8-methoxypsoralen administration in PUVA therapy.

Administration, Oral↗
PubMed1986

Effect of continued ultraviolet B phototherapy on the duration of remission of psoriasis: a randomized study.

Phototherapy using sunburn spectrum ultraviolet radiation (UVB) is now a frequently utilized treatment for psoriasis that is extensive or has not responded to topical preparations. Four university centers performed a prospective randomized clinical trial to compare remission times of patients with psoriasis who continued UVB phototherapy after initial clearing with this therapy and patients whose UVB phototherapy was discontinued within 3 weeks of clearing. As assessed by life table methods, the time to flare after initial clearing for patients on UVB maintenance therapy was significantly longer than for patients who discontinued UVB within 3 weeks after initial clearing. Our data suggest that continuing UVB phototherapy after initial clearing contributes to the duration of disease control and is justified for many patients.

Actuarial Analysis↗
PubMed1986

Topical retinoids: in vivo predictive assays.

Vitamin A is important for epithelial cell proliferation and differentiation and therefore has been used as a therapy for a variety of skin diseases. Synthetic vitamin A derivatives, called retinoids, have been used to treat a number of clinical skin conditions, including cystic acne and various forms of ichthyosis, Darier's disease, and psoriasis. Because of the toxicity of existing retinoids, newer vitamin A derivatives have been synthesized and must be evaluated in preclinical assays. Retinoids have profoundly differing biologic properties that can be evaluated selectively by studying their efficacy in different in vivo animal assays. This review will discuss some of the assays that may be useful predictors of retinoid efficacy.

Acne Vulgaris↗
PubMed1986

U.v. wavelength dependence for the induction of ornithine decarboxylase activity in hairless mouse epidermis.

Induction of mouse epidermal ornithine decarboxylase activity by u.v. radiation has been studied with a monochromator. Dose-response studies were carried out with 10 nm increments between 260 and 320 nm. Time-course studies were carried out at 280, 290 and 300 nm. Ornithine decarboxylase activity, assessed at 24 h post-irradiation, was induced in a dose-dependent fashion between 260 and 310 nm with peak activity at 280-290 nm. These data suggest that the chromophore is a protein.

Animals↗
PubMed1986

Differential rates of percutaneous absorption through the eczematous and normal skin of a monkey.

A monkey (Macaca fascicularis), diagnosed as having eczematous dermatitis on the basis of histopathology of a skin biopsy, was used to study the percutaneous absorption of 2 anti-inflammatory steroids. Absorption was measured through involved and uninvolved skin by using in vitro diffusion cell techniques. Hydrocortisone (0.5%) and triamcinolone acetonide (0.1%) were applied to the skin in a petrolatum vehicle. After application for 24 h, the permeation of hydrocortisone was approximately doubled (from 2.6 to 5.5% of the applied dose) when diseased skin was used. The absorption of triamcinolone acetonide was enhanced through the eczematous skin during the initial 12 h. At 24 h, however, no significant difference in total absorption was obtained.

Absorption↗
PubMed1986

Cutaneous phototoxicity reactions.

This paper reviews some potential mechanisms of cutaneous phototoxicity and discusses selected methods of predicting and ranking phototoxic reactions. Phototoxicity is a non-immunological reaction that is induced by the action of light on a photoactive chemical. The phototoxic chemical may be either exogenous or endogenous, and if exogenous may include topical or systemic agents. Examples of phototoxic agents include psoralens (e.g. 5-methoxypsoralen, 8-methoxypsoralen, as well as the isopsoralens). Psoralens are used therapeutically for the treatment of different skin diseases and psoralen-like chemicals may be present in perfumes and cosmetics. Phototoxic reactions can be evaluated visually in animals. The hairless mouse has also proved useful with skin thickening as a marker of dermal oedema and the induction of polyamine biosynthetic enzymes, as well as other biochemical changes being indicative of cutaneous phototoxicity. In vitro tests of phototoxicity include the Candida albicans assay as well as bacterial mutagenicity. For example, in the latter category different psoralens vary in their ability to induce mutagenicity in Salmonella typhimurium strains, an assay which can provide rapid screening of potential phototoxicity of chemicals. For human testing, phototoxic chemicals can be delivered topically or orally, and in conjunction with appropriate ultraviolet radiation will produce phototoxic reactions which can be evaluated for intensity of response.

Animals↗