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Biomedical subjects

K H Kaidbey

Publications and source records attributed to K H Kaidbey.

At least 55 records · Page 3Linked to original sources
PubMed1978

Phototoxicity to a sunscreen ingredient. Padimate A.

Para-aminobenzoic acid and certain of its esters are widely used in sunscreens. We found that one of these, amyl paradimethylaminobenzoate (padimate A) was capable of provoking phototoxic reactions; With ultraviolet A (UV-A) dosages of about 30 joules/sq cm, a reaction grossly resembling sunburn developed in most subjects. The dominant histological feature was vacuolar degeneration of the epidermis without sunburn cells. Proprietary sunscreens containing padimate A were also shown to produce a similar reaction. Our explanation for the paradox of a sunscreen that promotes "sunburn" is that, as affected users have concluded, the product was ineffective. The similarity between sunburn and a phototoxic response has delayed recognition of this adverse effect until now.

Adolescent↗
PubMed1977

Hair growth inhibition as a method of screening drugs for local antimitotic activity.

The intradermal injection of certain drugs with antimitotic properties in the guinea pig resulted in localized areas of reversible hair loss or hair growth inhibition. The size of the affected field was related to the dose. This may provide a useful and simple method for the rapid screening of potentially useful agents for local cytostatic activity.

Animals↗
PubMed1977

Clinical and histological study of coal tar phototoxicity in humans.

Coal tars of different origin were compared with regard to their capacity to cause a phototoxic reaction in human skin. The photosensitizing potencies were found to differ. Tars that were partially refined had less activity than crude coal tar. An extract of tar, liquor carbonis detergens, was the least photosensitizing. The phototoxic reaction to coal tar was found to be a two-stage process, an immediate wheal associated with sharp burning, followed by a raised, red, infiltrated lesion peaking at 24 to 48 hours. The phototoxic reaction was completely prevented when arterial blood flow was cut off. The histological findings were prominently epidermal, with strong intracellular edema sometimes leading to microvesicles. It seems a possibility that assaying phototoxic potentiality may provide a convenient measure of therapeutic efficacy of materials derived from coal tar.

Adrenal Cortex Hormones↗
PubMed1976

Assay of topical corticosteroids. Efficacy of suppression of experimental Rhus dermatitis in humans.

Rhus dermatitis, experimentally induced in humans, was used as a model for determining the efficacy of various proprietary topical steroids. One-centimeter squares of vesicular dermatitis were induced by patch application of Rhus oleoresin. The steroids were then applied without occlusion once daily for four days, with readings of the therapeutic effect taken on the fifth day. Only potent steroids provided unequivocal suppression in this severe test. The rank order of efficacy corresponded to clinical experience. Cream and ointment formulations of the same steroid at the same strength did not differ. High strength preparations were more effective than regular strengths. Relief of pruritus was an important early effect of efficaceous steroids.

Administration, Topical↗
PubMed1976

The influence of corticosteroids and topical indomethacin on sunburn erythema.

The extent to which topical and intradermal corticosteroids and topical indomethacin suppress sunburn erythema was investigated in human volunteers. Both agents retarded the onset and decreased the magnitude of delayed erythema. Suppression by corticosteroids was not demonstrable with ultraviolet doses larger than 2 MEDs (minimal erythema dose). Below 2 MEDs, topical betamethasone valerate produced a dose-related suppression of erythema. Indomethacin was more effective and produced a measurable dose-dependent suppression against 3 and 6 MEDs. Despite significant inhibition of erythema, sunburn damage to epidermal cells was not altered by these drugs.

Administration, Topical↗
PubMed1976

Therapy of resistant psoriasis with topical corticosteroids and dimethylsulfoxide.

The sequential application of full-strength dimethylsulfoxide (DMSO) and potent topical corticosteroid preparations was very effective in resistant plaque-type psoriasis. Complete clearing may be achieved in 3-4 weeks. Lower strengths of DMSO were less beneficial. Irritation from the solvent was effectively controlled by corticosteroids and was limited to transient burning or stinging. Resistance to topical corticosteroids may be overcome by the concomitant use of DMSO.

Administration, Topical↗
PubMed1975

Further studies of photoaugmentation in humans: phototoxic reactions.

The addition of modest amounts of long ultraviolet light (UV-A) to 1/2 minimal erythema dose (MED) of sunburning irradiation (UV-B) produced erythema visible at 24 hr, the prototype of the photoaugmentation phenomenon. The results were the same whether UV-A was given before or after UV-B. Photoaugmentation could be demonstrated after an inverval of 6 hr between doses, but not after 1 day. Photoaugmentation has also been demonstrated clinically and histologically with two topical photosensitizers, coal tar and 8-methoxy-psoralen.

Adult↗
PubMed1975

Effects of intensive application of retinoic acid on human skin.

The daily application of 0-3% retinoic acid to the back produced an acute irritant dermatitis which resolved to a near-normal clinical appearance within 40 days despite continued daily exposure. Hardened skin was markedly altered physiologically. The responses to DMSO, histamine and the histamine liberator, compound 48/80, were sharply enhanced. This reflected enhanced permeability resulting from reduction of the horny layer to less than one-half its normal thickness. Phototoxic and irritant substances produced exaggerated reactions owing to greater penetration. A paradoxical decrease in delayed sinsitivity to streptodornase-streptokinase was attributed to enhanced clearance of the antigen.

Adult↗
PubMed1975

Topical colchicine therapy for recalcitrant psoriasis.

Once daily applications of 1.0% colchicine in hydrophilic ointment for 6 to 12 weeks produced substantial resolution of recalcitrant psoriatic plaques, especially those on the trunk. With occlusion, lower concentrations of the drug (0.25% and 0.50%) were usually effective. A thick viscous base (hydrophilic petrolatum) was more effective than a hydrophilic cream base (hydrophilic ointment), presumably because of greater occlusivity. Treatment with topically applied colchicine may be valuable when other measures fail to control localized thick plaques of psoriasis. Its use is still experimental and should be restricted to small areas until more is known about its percutaneous absorption.

Administration, Topical↗
PubMed1975

Treatment of psoriasis with topically applied tretinoin and steroid ointment.

The sequential application of tretinoin and a corticosteroid ointment was considerably more effective in the treatment of plaque-type psoriasis than either drug alone in a pilot study. The best results were obtained with 0.3% tretinoin followed by a potent corticosteroid ointment. Combined therapy was particularly efficacious in steroid-resistant psoriasis, including that on the palms, elbows, and knees. Irritancy from the high-strength tretinoin was a potentially troublesome side-effect. Care must be taken to avoid drug contact on areas that are easily irritated.

Administration, Topical↗