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Biomedical subjects

C M Lawrence

Publications and source records attributed to C M Lawrence.

At least 109 records · Page 6Linked to original sources
PubMed1985

Comparison of ultrasound and caliper measurements of normal and inflamed skin thickness.

We have compared ultrasound and Harpenden calipers for the measurement of thickness of non-inflamed and anthralin-inflamed skin. In non-inflamed skin ultrasound gave consistently and significantly lower values (0.87 mm +/- 2.3% s.e.) than calipers (1.1 mm +/- 2.7% s.e.) and the ultrasound/caliper ratio was 0.89 +/- 1.3%. In anthralin-inflamed skin the ultrasound/caliper ratio was not significantly different from unity (1.02 +/- 1.3%), but ultrasound was unable to measure inflamed skin thickness in 18% of cases because the echo could not detect the dermis-subcutaneous fat interface. The proportion of unreadable ultrasound results increased linearly with increase in skin thickness and the variance of ultrasound readings increased as inflammatory skin thickness increased; by contrast caliper variance remained constant. Harpenden calipers cannot be used in all subjects or in skin sites in which skin folds cannot be raised, but if the patient and site to be studied can be selected, Harpenden calipers have a greater precision, reproducibility and reliability than ultrasound for measurement of the thickness of inflamed skin.

Anthralin↗
PubMed1985

Mechanism of anthralin inflammation. I. Dissociation of response to clobetasol and indomethacin.

The effect of topical clobetasol propionate and a 1% topical indomethacin gel which could inhibit UV erythema was measured on anthralin inflammation by change in skin-fold thickness and erythema. The time course of the inflammatory oedema and erythema were different, as was their response to the drugs studied. The oedema of anthralin inflammation was completely inhibited by clobetasol propionate but the erythemal response showed a small and non-significant reduction. Indomethacin had no effect on anthralin oedema but produced a small but significant reduction in erythema in the first 24 h after anthralin application. These results suggest that either anthralin inflammation is not due to production of prostenoids, or that if it is, it occurs by other than the classical enzymic pathway.

Adult↗
PubMed1985

Mechanism of anthralin inflammation. 2. Effect of pretreatment with glucocorticoids, anthralin and removal of stratum corneum.

The inflammatory dose-response to anthralin was measured in human skin 24 h after pretreatment with topical corticosteroids and anthralin, and 48 h after removal of the stratum corneum with adhesive tape. Anthralin inflammation was increased after 1% hydrocortisone application and decreased by 0.1% betamethasone valerate and 0.05% clobetasol propionate; although the difference between these effects was not significant, the difference between the effect of hydrocortisone and clobetasol propionate was. Anthralin inflammation was not significantly affected by pretreatment with anthralin and was reduced, although not significantly by removal of the stratum corneum. The finding that anthralin inflammation is not altered in skin in which aryl hydrocarbon hydroxylase (AHH) activity is increased and that anthralin inflammation may be altered in situations in which AHH activity is unchanged, excludes a direct relationship between anthralin inflammation and AHH activity.

Administration, Topical↗
PubMed1985

Plasma bile salt levels in patients presenting with generalised pruritus: an improved indicator of occult liver disease.

Fasting plasma bile salt concentrations were measured in 26 patients presenting to a Skin Department who had generalised pruritus without primary skin disease, as part of a screening investigation for systemic causes of pruritus. The results were compared with conventional tests of hepatic function. Plasma-conjugated cholate measurements identified all patients with hepatobiliary disease. Conventional liver function tests were abnormal in these patients but also in five patients with no other evidence of hepatic dysfunction. Fasting conjugated-cholate measurements offer a useful screening test for identifying hepatobiliary disease in patients presenting with generalised pruritus.

Adult↗
PubMed1984

Inhibition of dithranol inflammation by free-radical scavengers.

Dithranol (anthralin) inflammation of forearm skin was completely inhibited by various scavengers of free radicals of the oxygen species. It is concluded that dithranol inflammation is initiated by formation of free radicals; these may act through lipid peroxidation and production of inflammatory endoperoxides or by a more direct mechanism.

Administration, Topical↗
PubMed1984

Two patterns of skin ulceration induced by methotrexate in patients with psoriasis.

Two patterns of skin ulceration occurred in patients receiving weekly methotrexate for psoriasis. In type I ulceration, psoriatic plaques became painful and eroded shortly after starting methotrexate (MTX) (median, 10 days). Type II ulcers occurred in clinically uninvolved skin affected by other pathology--stasis dermatitis in two and adjacent to an anal fistula in one and had a variable relationship to the duration of methotrexate treatment. Type I ulcers developed at methotrexate doses between 12.5 and 25 (median, 20) mg/wk and healed rapidly (median, 10 days) after dose reduction or withdrawal. Type II ulcers developed at methotrexate doses of 7.5 to 20 (median, 10) mg/wk and took a median of 9 weeks to heal. Type I ulceration may be confused with an exacerbation of psoriasis, and the MTX dose mistakenly increased rather than reduced. Type II ulcers can mimic stasis ulcers and may be overlooked as evidence of MTX toxicity.

Adult↗
PubMed1984

Human skin aryl hydrocarbon hydroxylase.

Aryl hydrocarbon hydroxylase (AHH) activity has been measured in full-thickness biopsies of human skin from patients with and without psoriasis. Basal levels of enzyme activity varied over a fivefold range and were not related to age, sex or clinical condition. Induction of AHH activity by the application of coal tar resulted in a two- to fivefold increase in activity above basal levels, which was not related to the presence or absence of psoriasis. Separation of human skin into dermis and epidermis showed that human skin AHH activity is predominantly dermal.

Adolescent↗
PubMed1984

Effect of coal tar on cutaneous aryl hydrocarbon hydroxylase induction and anthralin irritancy.

The inflammatory dose-response to topical anthralin and whole skin aryl hydrocarbon hydroxylase (AHH) activity were measured before and 24 h after application of a coal tar solution to the uninvolved skin of patients with psoriasis. The inflammatory response to anthralin decreased and total AHH activity increased after the tar treatment. A possible explanation is that anthralin or an irritant product is metabolized by AHH activity in the skin. Induction of AHH by coal tar increases its removal and reduces anthralin irritancy.

Adult↗
PubMed1984

A comparison of PUVA-etretinate and PUVA-placebo for palmoplantar pustular psoriasis.

Seventeen patients with palmoplantar pustular psoriasis and three with hyperkeratotic psoriasis of palms and soles were treated with either PUVA-etretinate (1 mg/kg) or PUVA-placebo. Patients were randomly allocated to each group and the trial was conducted according to a double-blind protocol, so far as the side-effects of etretinate made this possible. PUVA was given three times a week for a maximum of 18 weeks, after 2 weeks on daily placebo or etretinate alone. All ten patients in the PUVA-etretinate group cleared, but there were four failures in the PUVA-placebo group (P = 0.03). The PUVA-etretinate treated patients required significantly fewer PUVA treatments (13.1 +/- 2.9; mean +/- s.e.) and cleared in a significantly shorter time (30.3 +/- 7.1 days) than the PUVA-placebo group (23.2 +/- 4.2 treatments; 59.2 +/- 11.5 days, P less than 0.05). The cumulative UV-A dose to clear was less in the PUVA-etretinate group (53.9 +/- 18.5 J/cm2) than the PUVA-placebo group (113.1 +/- 33.4 J/cm2). This difference was not significant due to the exceptionally large dose of UV-A used on one patient but the results were significant when it was excluded. The therapeutic advantage of adding etretinate to PUVA is offset by the side-effects of cheilitis, hair loss and peeling skin which occurred in eight of the ten PUVA-etretinate patients, and an increase in fasting triglyceride concentrations and serum alkaline phosphatase activity.

Etretinate↗
PubMed1983

Aryl hydrocarbon hydroxylase activity and psoriasis.

Aryl hydrocarbon hydroxylase (AHH) has been measured in the skin, jejunum and liver of normal and psoriatic individuals. We have been unable to confirm previous reports of an abnormality in AHH activity in patients with psoriasis. Re-examination of the laboratory records on which the original reports were based leads us to doubt their veracity and validity.

Animals↗
PubMed1983

Assessment of liver function using fasting bile salt concentrations in psoriasis prior to and during methotrexate therapy.

To determine if fasting bile salt concentrations are an accurate indicator of pre-existing and methotrexate-induced liver disease in patients with psoriasis, the plasma concentrations of conjugated cholate, chenodeoxycholate and sulpholithocholate were measured in 18 patients being assessed for methotrexate therapy and 21 receiving long-term therapy. The results were compared with other liver function tests and liver histology. The liver function tests were a poor indicator of occult liver disease and, whilst fasting bile salts appeared more sensitive, they were still unreliable and inadequate for the clinical assessment of the hepatopathy associated with psoriasis. The reasons for these discrepancies are discussed.

Adult↗
PubMed1982

Ampliative medicament allergy: concomitant sensitivity to multiple medicaments including yellow soft paraffin, white soft paraffin, gentian violet and Span 20.

A patient developed multiple rare medicament contact allergies including sensitivities to gentian violet, yellow and white soft paraffin, and Span 20 (sorbitan monolaurate). Nickel sensitivity antedated these medicament allergies. The possibility that nickel sensitivity is a marker of predilection to develop multiple medicament allergies was tested. We were unable to demonstrate an increased incidence of nickel sensitivity in a group of patients with 2 or more medicament allergies.

Adult↗