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Biomedical subjects

J L Fewkes

Publications and source records attributed to J L Fewkes.

3 recordsLinked to original sources
PubMed1996

Complications of cutaneous surgery in patients who are taking warfarin, aspirin, or nonsteroidal anti-inflammatory drugs.

BACKGROUND AND DESIGN: No controlled studies exist with regard to the risks of continuing therapy with warfarin sodium or platelet inhibitors or the benefits of briefly discontinuing therapy with these agents in patients who are undergoing cutaneous surgical procedures. Our objective was to determine the frequency of complications of cutaneous surgery in patients who were receiving warfarin or platelet inhibitors and to evaluate whether preoperative discontinuation reduces complications. A retrospective, controlled study was performed of complications of excisional and Mohs micrographic surgery in 653 patients who were being treated with warfarin or platelet inhibitors or with their medications being briefly withheld. RESULTS: Severe complications of cutaneous surgery in patients who are taking warfarin or platelet inhibitors are uncommon, occur in 1.6% of cases, and are not significantly increased compared with complications in control subjects. Furthermore, there was no statistically significant reduction in the rates of severe complications in patients who had their medications preoperatively held. CONCLUSION: Cutaneous surgery in patients who receive warfarin or platelet inhibitors is associated with a low risk of severe complications, not significantly reduced by brief preoperative discontinuation.

Adolescent↗
PubMed1995

Lack of selectivity of protoporphyrin IX fluorescence for basal cell carcinoma after topical application of 5-aminolevulinic acid: implications for photodynamic treatment.

Clinical trials of topical ALA in photodynamic therapy (PDT) of basal cell carcinoma (BCC) show significant recurrence rates. Exogenous 5-aminolevulinic acid (ALA) is converted by intracellular enzymes to photoactive protoporphyrin IX (PpIX) in human tissues. PpIX generates cytotoxic singlet oxygen when irradiated with visible light in the 400-640 nm range. To evaluate variability and heterogeneity in PpIX production by tumors in such trials, and to assess the usefulness of PpIX for marking skin tumors, we measured PpIX fluorescence distribution in BCC after topical application of 20% ALA cream. ALA cream was applied under occlusion for periods ranging from 3 to 18 h (average 6.9 h, SD 4 h) to 16 BCCs. ALA conversion to PpIX in the BCCs was assessed by in vivo photography, ex vivo video fluorescence imaging, and fluorescence microscopy. External macroscopic PpIX fluorescence, as assessed by in vivo and ex vivo imaging, correlated with the clinical presence of BCC. Examination by a digital imaging fluorescence microscope revealed inter- and intratumor fluorescence variability and heterogeneity. PpIX fluorescence corresponding to full tomor thickness was found in six superficial and four nodular tumors, and partial-thickness fluorescence was observed in five nodular tumors, but no PpIX fluorescence was observed in some areas of superficial, nodular and infiltrating tumors. In a significant number of nodular and infiltrating BCCs, topical ALA appeared to provide little or no PpIX in deep tumor lobules. In addition, no selectivity for tumor tissue versus normal epidermis was seen. The grossly brighter external PpIX fluorescence over tumors may be due, therefore, to enhanced penetration through tumor-reactive stratum corneum and to the tumor thickness.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Cutaneous↗