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Biomedical subjects

D S Wilkinson

Publications and source records attributed to D S Wilkinson.

At least 73 records · Page 4Linked to original sources
PubMed1978

Triclocarban: evaluation of contact dermatitis potential in man.

Triclocarban was subjected to a profiling of its dermatitis producing potential including irritancy (21-day cumulative irritancy potential and application to 213 normal controls), phototoxicity (method of Marzulli), predictive contact sensitization (modified Draize method), predictive phototesting and battery screening in 2200 dermatitis patients, in an effort to define its relative dermatitis potential. The allergic contact dermatitis potential of triclocarban following bar soap use appears minimal.

Carbanilides↗
PubMed1978

[Some atypical forms of eczema in children (author's transl)].

Among 466 children under the age of 12 years who presented with eczema in a 5-year period, 68 p. 100 were atopic. 136 had various atypical signs of atopy. 44 suffered from pityriasis alba of sufficient intensity to justify referral for this reason; 10 had the typical features of seborrhoeic dermatitis of infants. 27 suffered from "forefoot" eczema ("juvenile plantar dermatosis"). The course and characteristics of this condition are discussed and compared with the series recently described in the West of Scotland. Our cases were exactly similar except for an aggravation in the summer months and the fact that our cases responded poorly to topical corticosteroids alone though improved with coal tar. Atopy and contact sensitivity to shoe materials are rare in both groups. We feel that this may be classified as "frictional" dermatitis and agree with our Scottish colleagues that the introduction of nylon socks during the last ten years may be important.

Child↗
PubMed1977

Metabolism of 5-fluorouracil in sensitive and resistant Novikoff hepatoma cells.

N1-S1/FdUrd Novikoff hepatoma cells, which lack thymidine kinase activity, are resistant to 5-fluorouracil (FUra) as well as 5-fluorodeoxyuridine (FdUrd), suggesting that the pathway, FUra leads to FdUrd leads to FdUMP, is utilized for the conversion of FUra to FdUMP. However, the inhibition of thymidylate synthetase activity, the presumed target of FdUMP, by 1 X 10(-4) M FUra in intact N1-S1 Novikoff hepatoma cells, which have significant levels of thymidine kinase activity, is completely eliminated by 5 X 10(-4) M hydroxyurea, which is a potent inhibitor of ribonucleotide reductase. These results imply that the formation of ribonucleotides and does not involve thymidine kinase. This apparent dichotomy can be explained by the fact that, in addition to the well known lack of thymidine kinase activity, [14C]FUra conversion to ribonucleotides is greatly depressed in the N1-S1/FdUrd cells. Hence, the formation of FdUMP from FUra in Novikoff hepatoma cells apparently proceeds primarily via the intermediate formation of ribonucleotides. The decreased conversion of FUra to ribonucleotides in N1-S1/FdUrd cells decreases not only the ability of the analog to inhibit DNA synthesis, but also its effect on RNA metabolism. FUra, at a concentration of 1 X 10(-5) M, inhibits rRNA maturation in N1-S1 cells, but not in N1-S1/FdUrd cells. Since N1-S1/FdUrd cells are completely resistant to 1 X 10(-5) M FUra, whereas N1-S1 cells are completely inhibited by 1 X 10(-5) M FUra, even in the presence of 1 X 10(-4) M thymidine, the effects of FUra on RNA metabolism appear to contribute significantly to the cytotoxicity of the analog at higher drug concentrations.

Animals↗
PubMed1977

Lanolin with reduced sensitizing potential. A preliminary note.

The allergens of lanolin appear to lie in the content of natural free fatty alcohols rather than in the total alcohols as hitherto supposed. The detectable incidence of allergy is increased by the simultaneous presence of detergent. Amongst selected lanolin-sensitive skin patients, removal of both free fatty alcohols and detergent from lanolin reduces the incidence of detectable hypersensitivity by 96%. Methods are described for determining free fatty alcohols and detergent in lanolin, and for removing them.

Dermatitis, Atopic↗
PubMed1977

Black heel a minor hazard of sport.

"Black heel" (calcaneal petechiae) is a traumatic lesion affecting the back or posterolateral aspect of the heel. It is seen almost exclusively in adolescentes or young adults engaged in active sports, notably basketball, but also football, lacrosse, tennis, and so forth. The lesion is disposed horizontally at the upper dege of the calcaneal fat-pad and consists of grouped punctate hemorrhages, the nature of which is revealed by repeated paring of the lesion. The nature of the pigment is shown by specialized stains. "Black heel" is probably more common than is realized. It is likely to be cuased by a shearing or pinching stress from abrupt contact of th foot with a floor or hard ground. As it si usually symptomless, it may be disregarded or only observed by chance. However, it has been confused clinically with a melaonoa, and as it is such a trivial self-healing process, it is important that it be recognized for what it is.

Adolescent↗
PubMed1976

The mechanism of 5-fluorouridine toxicity in Novikoff hepatoma cells.

The mechanism of 5-fluorouridine (FUrd) cytotoxicity in Novikoff hepatoma cells appears to vary under different experimental conditions. Continuous exposure to 1 X 10(-7) M FUrd results in a simple thymineless death that can be prevented by the addition of 1 X 10(-4) M thymidine to the culture medium. In contrast, 1 X 10(-4) M thymidine does not prevent the growth inhibition caused by a 1-hr exposure to 1 X 10(-5) M FUrd, despite the fact that it does prevent the inhibition of DNA synthesis. Although it has no effect on the inhibition of DNA synthesis, 1 X 10(-4) M uridine prevents the growth inhibition caused by a 1-hr exposure to 1 X 10(-5) M FUrd. Since 1 X 10(-4) M uridine, but not 1 X 10(-4) M thymidine, prevents the inhibition of ribosomal RNA maturation caused by a 1-hr exposure to 1 X 10(-5) M FUrd, it seems likely that the effects of the analog on RNA metabolism contribute significantly to the cytotoxic activity of the analog in this specific experimental situation.

Antineoplastic Agents↗
PubMed1975

Careers advice to youths with atopic dermatitis.

Adolescents who have suffered from atopic dermatitis frequently start training or apprenticeship for unsuitable jobs. The School Medical Serivce and the Youth Employment Service have now been linked with the Employment Medical Advisory Service to afford help to such young people. It is suggested that family doctors and parents be reminded of this with Guidance Notes.

Adolescent↗
PubMed1975

Cinnamic aldehyde in toothpaste. 1. Clinical aspects and patch tests.

Although cinnamon is known to cause dermatitis in bakers and confectioners, it has only rarely been reported as causing trouble in food or cosmetics. A newly-formulated 'spicy' toothpaste containing cinnamon as a flavouring agent was the cause of oral symptoms in eight patients referred to clinics in Buckinghamshire and in Malmö and in a further eight patients discovered subsequently. Similar symptoms and patch test results were observed independently at both centres. Positive reactions were obtained with 1% cinnamic aldehyde in 15 out of 16 patients tested. Only one patient reacted to a standard sample of balsam of Peru (25% in petrolatum).

Acrolein↗
PubMed1975

Sensitivity to cinnamic aldehyde in a toothpaste. 2. Further studies.

The authors carried out further studies to assess the significance of the findings of patients sensitive to cinnamic aldehyde in a toothpaste. Selected groups of patients in whom sensitivity to this might have been overlooked were patch-tested. With the exception of three patients, two with cosmetic sensitivity and one with hand eczema, the results were negative. The frequency of use of the original toothpaste was assessed among patients attending the clinic and this was followed by a circular letter to general practitioners and dentists inviting referral of patients with oral symptoms. As a result, five further cases, four of whom gave positive patch test reactions to cinnamic aldehyde, were discovered. The authors emphasize the importance of attempting to obtain accurate information as quickly as possible when 'new' or hitherto unsuspected allergens are implicated.

Acrolein↗
PubMed1975

The inhibition of ribosomal RNA synthesis and maturation in Novikoff hepatoma cells by 5-fluorouridine.

The inhibition of ribosomal RNA (rRNA) maturation by 5-fluorouridine (FUrd) in Novikoff hepatoma cells appears to depend upon the incorporation of the analog into the 45 S rRNA precursor. Precursor synthesized in the presence of FUrd is not processed into mature rRNA, but precursor synthesized in the absence of the analog is processed normally after the addition of the drug. The effect of FUrd on rRNA maturation is concentration dependent. At a concentration of 1 X 10(-4)M, the analog completely inhibits the formation of mature 18 S and 28 S rRNA; while at a concentration of 1 X 10(-7)M, the analog has no significant effect on rRNA maturation. These results suggest that some minimum degree of analog substitution is necessary to inhibit the maturation process. In addition to its inhibition of maturation, FUrd also inhibits the transcription of 45 S rRNA precursor. However, this effect of the drug is less complete and more time dependent that the effect on maturation. The inhibition of rRNA maturation by FUrd persists after removal of the analog from the culture medium. Cells that had been exposed to FUrd for 2 hr were unable to process 45 S rRNA precursor 20 hr after removal of the drug from the medium.

Animals↗