Biomedical subjects
Publications and source records attributed to S M Allan.
In 1948 Dr Sophie Spitz described criteria that distinguished juvenile melanoma from malignant melanoma. Since then the cases of eruptive Spitz naevi have been reported arising on normal skin, on lightly pigmented patches and on hypopigmented patches. There are only 12 reports of Spitz naevi arising on hyperpigmented patches: we describe here three further cases, all on the arms of children, seen in our department in a single year.
Lymph node status is still the single most important prognostic factor in breast cancer. Axillary surgery remains the only reliable means of providing this information. This pilot study evaluates using a highly specific radiolabelled monoclonal antibody to provide equivalent information by a non-invasive technique. After optimisation of labelling conditions, our first antibody, ICR12 (against the gene product of c-erbB-2) was evaluated in a mouse model system. Twenty-four hours post i.v. injection the mice were killed and their organs, blood and tumours harvested for counting. Tumour localisation was four times greater than that into normal tissues, reaching 20% injected dose per gram of tumour. Eight patients have had this Tc99m-ICR12. Patient selection was by immunocytochemical staining of fine needle aspirates from the patient's own breast cancer. After intravenous administration of the immunoconjugate, tomographic images were obtained at 24 h. These results were compared to the subsequent histopathological examinations. Three patients acted as normal controls, one patient was negative due to inappropriate sampling, and two patients had strong membrane staining and provided excellent tumour localisation to both breast primary and regional node metastases. A further two patients only had moderate antigen expression on staining and did not localise well. The good performance of this radiolabelled antibody with patients that strongly stain for the antigen encourages the development of this system as both a method of staging breast cancer and a potential means of immunotherapy in this subgroup of patients.
The results of the determination of c-erbB-2 gene expression by immunocytochemical staining of cytological aspirates, prepared by cytocentrifugation, have been compared with paraffin-embedded tissue sections from the same tumour. Our results show equivalent staining in 20/22 cases, with six cases being both scored positive and fourteen cases being both negative. Two samples gave conflicting results. One case was scored as being positive on the cytological aspirate, whereas in the tissue sections taken from the same tumour positive staining was only seen in areas of non-invasive intraduct carcinoma. This sample was scored as being negative. In another case, cytoplasmic staining with less than 50% of the cells showing any positivity was observed in the cytospin sample, with negative staining in the corresponding tissue section. We conclude that expression of c-erbB-2 immunostaining is detectable on cytological preparations prepared by cytocentrifugation but must be interpreted with caution in tumours which may have a large intraduct component or which give predominant cytoplasmic staining.
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A two-stage chromatographic procedure has been devised for the measurement of 7-dehydrocholesterol in human skin. Extracts containing ergosterol as internal standard underwent preparative chromatography on a Spherisorb S5W column using hexane-1% isopropanol as solvent, and an eluted fraction was analysed with an Ultrasphere 5-microns ODS column with methanol-tetrahydrofuran-17.5 mM KH2PO4 (95:1:4, v/v) as solvent and using an amperometric detector at 1.7 V. 7-Dehydrocholesterol could be reliably assayed in human skin samples as small as 5 mm in diameter. In hospital patients skin 7-dehydrocholesterol concentrations ranged from 12 to 81 micrograms/g dry weight.
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This is a study of the use of myocutaneous flaps by general surgeons in a district general hospital over a 5 year period, and shows that such work can be satisfactorily performed by general surgeons.
We present the technique and our results in using a plug of Prolene mesh to repair femoral hernias. By filling the femoral canal with a Prolene plug we achieved a sound hernia repair. Our results allow us to recommend the technique to others.
A method for the analysis of valproic acid in plasma or serum has been developed. The specimen is deproteinized with acetonitrile containing nonanoic acid as internal standard and an aliquot of supernate is heated at 70 degrees C for 15 min with 4-bromophenacyl bromide at pH 7. An aliquot of the reaction mixture is subjected to reverse phase high performance liquid chromatography at ambient temperature and a detector wavelength of 254 nm. Drug and internal standard eluted within 6 min. The method correlated well with a gas chromatographic procedure. Recoveries ranged from 85 to 108% and the day-to-day coefficients of variation ranged from 3.8 to 10.7%.
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