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Biomedical subjects

W Weightman

Publications and source records attributed to W Weightman.

10 recordsLinked to original sources

The effect of excess protamine on thrombelastography in vitro.

The aim of the current study was to assess the direct effect of protamine on conventional thrombelastography in vitro. Protamine was added to blood samples collected from 25 adult cardiac surgical patients prior to the induction of anaesthesia and after separation from cardiopulmonary bypass. The final protamine concentrations were 0 (control), 0.05 mg/ml, 0.1 mg/ml and 0.2 mg/ml (i.e. sufficient to reverse heparin 0, 5, 10 and 20 IU/ml respectively, assuming a 1:1 reversal ratio). In the pre-induction samples, protamine was associated with increases in r time and reductions in maximum amplitude (P<0.01). After bypass, the control samples demonstrated a heparin effect as expected, which was corrected by the addition of protamine 0.05 mg/ml. However, the higher concentrations of protamine were again associated with increases in r time and reductions in maximum amplitude (P<0.01). The results indicate that protamine has a direct anticoagulant effect on conventional thrombelastography in vitro. This effect occurs whether protamine is present alone, or whether protamine is present in excess after neutralization of heparin. Unless this effect is taken into account, excess protamine may confound the interpretation of conventional thrombelastography in cardiac surgical patients.

Adult↗

Photodynamic therapy with topical methyl aminolaevulinate for 'difficult-to-treat' basal cell carcinoma.

BACKGROUND: Basal cell carcinoma (BCC) may be difficult to treat by conventional means, particularly if the lesions are large or located in the mid-face (H-zone). Photodynamic therapy (PDT) using topical methyl aminolaevulinate (MAL) may be a good noninvasive option for these patients. OBJECTIVES: To investigate the efficacy and safety of PDT using MAL for BCCs defined as 'difficult to treat', i.e. large lesions, in the H-zone, or in patients at high risk of surgical complications. METHODS: This was a prospective, multicentre, noncomparative study. Patients were assessed 3, 12 and 24 months after the last PDT treatment. One hundred and two patients with 'difficult-to-treat' BCC were treated with MAL PDT, using 160 mg g(-1) cream and 75 J cm(-2) red light (570-670 nm), after lesion preparation and 3 h of cream exposure. Results Ninety-five patients with 148 lesions were included in the per protocol analysis. The histologically confirmed lesion complete response rate at 3 months was 89% (131 of 148). At 12 months, 10 lesions had reappeared, and therefore the cumulative treatment failure rate was 18% (27 of 148). At 24 months, an additional nine lesions had reappeared, resulting in a cumulative treatment failure rate of 24% (36 of 148). The estimated sustained lesion complete response rate (assessed using a time-to-event approach) was 90% at 3 months, 84% at 12 months and 78% at 24 months. Overall cosmetic outcome was judged as excellent or good in 79% and 84% of the patients at 12 and 24 months, respectively. Follow-up is continuing for up to 5 years. CONCLUSIONS: MAL PDT is an attractive option for 'difficult-to-treat' BCC. Because of the excellent cosmetic results, the treatment is particularly well suited for lesions that would otherwise require extensive surgical procedures.

Administration, Topical↗

A comparison of photodynamic therapy using topical methyl aminolevulinate (Metvix) with single cycle cryotherapy in patients with actinic keratosis: a prospective, randomized study.

BACKGROUND: Actinic keratosis (AK) is a very common condition, which has the potential of progressing to squamous cell carcinoma. The present study is a prospective, randomized study comparing the lesion response, cosmetic outcome, patient satisfaction and tolerability of a new treatment modality, photodynamic therapy (PDT), using topical methyl aminolevulinate (Metvix), with the most commonly used standard therapy for AK, cryotherapy. METHODS: A total of 204 patients with clinically diagnosed AK were randomized to either cryotherapy or PDT. The PDT patients were further assigned to an active or placebo group in a random, double-blind manner. Cryotherapy was performed using liquid nitrogen spray in a single freeze-thaw cycle. PDT was performed using 160 mg/g methyl aminolevulinate cream or placebo, a 3-hour application time, red light (570-670 nm) and a total light dose of 75 J/cm(2). PDT was repeated after 7 days. Two sessions of PDT were undertaken, as a previous study had shown a single session had similar efficacy to cryotherapy. Lesion response was assessed clinically after 3 months (complete response or non-complete response). RESULTS: The lesion response rate was 91% in the methyl aminolevulinate PDT group, 68% in the cryotherapy group and 30% in the placebo PDT group. Methyl aminolevulinate PDT was statistically significantly better than both cryotherapy and placebo PDT in terms of response rates and cosmetic outcome. Most patients preferred PDT to other treatments. CONCLUSIONS: PDT with methyl aminolevulinate is an excellent treatment option, particularly for patients with widespread damage or AK lesions in cosmetically sensitive areas.

Administration, Cutaneous↗

Bullous pemphigoid induced by cephalexin.

Two young men developed severe bullous eruptions with a distinctive clinical picture of severe flexural involvement and extensive mucosal ulceration. Biopsies showed subepidermal bullae and associated inflammation consisted of predominantly neutrophils. Both had IgG and C3 staining of the dermal-epidermal junction on direct immunofluorescence. Bullous pemphigoid was diagnosed on the basis of clinical, histopathological and immunofluorescence findings. Both cases occurred after recent ingestion of cephalexin. We believe they represent the first reported cases of bullous pemphigoid induced by cephalexin.

Adrenal Cortex Hormones↗

A case of atrophoderma vermiculatum responding to isotretinoin.

Atrophoderma vermiculatum (AV) is a rare disorder leading to reticular or honeycomb scarring of the face and responding poorly to treatment. A case is now presented of the successful induction of remission in the inflammatory component of the disease following a prolonged course of isotretinoin; improvement was then maintained after cessation of the treatment. In severe cases of AV with significant scarring, a trial of isotretinoin therapy is thus worthwhile in an attempt to stop progression of the disease and improve its cosmetic appearance.

Child↗

Effect of an ointment containing boric acid, zinc oxide, starch and petrolatum on psoriasis.

A randomized double-blind controlled trial was undertaken to study the efficacy of a cow udder ointment versus petroalatum alone. A total of 30 patients participated in the study. Sixteen patients completed the trial with 8 of 9 patients improving in the active group and 6 of 7 patients improving in the placebo group. This difference was not statistically significant. The use of a cow udder ointment for psoriasis cannot be supported, particularly with the potential for side effects.

Administration, Topical↗

Toxic epidermal necrolysis.

Toxic epidermal necrolysis (TEN) is a rare, drug-induced, life-threatening syndrome with widespread epidermal loss and mucosal erosions. The classification, pathophysiology, clinical features and treatment are discussed in this review. Prognosis has improved as admission to a burns unit and early treatment of infection has become standard management. The role of corticosteroids in treatment is still controversial.

Humans↗

Formulation of 1-alpha,25-dihydroxycholecalciferol topical ointment for psoriasis treatment.

A means of accurate and rapid formulation of 1-Alpha,25-dihydroxycholecalciferol topical ointment is described. The accuracy of the formulation technique is within 95% of the theoretical ointment concentration (lug/gram of petrolatum base). Moreover, the stability of the formulated ointment is examined at room temperature (21 degrees C) and refrigerated (2 degrees C) over 40 days storage. When protected from light the loss of potency is 6% at 21 degrees C and negligible at 2 degrees C.

Administration, Topical↗