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Biomedical subjects

H M McCallum

Publications and source records attributed to H M McCallum.

12 recordsLinked to original sources
PubMed1996

Long-term culture of primary breast cancer in defined medium.

Over a period of 6 1/2 years between January 1986 and May 1992, 135 unselected primary breast cancers were cultured and of these 10 developed into cell lines. Six of the lines grew in defined serum-free medium, while the other four required supplementation with 0.5% fetal calf serum. Two of the lines are from the same breast, being derived from a local excision specimen and from a mastectomy specimen 12 months later. In addition, 12 lymph nodes containing metastatic breast cancer were cultured; one of these cultures became permanent in a defined serum-free medium. Oestrogen receptor (ER) status was negative in all but one of the tumours which grew successfully, and even in this case the derived cell line is ER negative. The epithelial nature of the lines has been confirmed by immunocytochemistry and by electron microscopy (EM), while their malignant nature is shown by morphology, unattached growth, chromosome analysis, and, in the case of the line from a lymph node metastasis, the absence of any benign source of epithelial cells.

Adult↗
PubMed1993

Co-amplification of erbB2, topoisomerase II alpha and retinoic acid receptor alpha genes in breast cancer and allelic loss at topoisomerase I on chromosome 20.

The DNA topoisomerase enzymes are targets for the cytotoxic effects of a number of anticancer agents termed topoisomerase inhibitors. We have analysed breast cancer biopsy specimens for genetic alterations at and around topoisomerase loci in order to obtain molecular insight into factors which may determine how tumours respond to chemotherapy. We show that of 50 tumours examined, the topoisomerase II alpha locus is co-amplified in 3 cases out of 6 with erbB2 amplification and that amplification can be accompanied by high expression of topoisomerase II alpha. In our attempts to distinguish amplification from aneuploidy and define the limits of amplification, we also observed co-amplification of the retinoic acid-alpha receptor with erbB2 and topoisomerase II alpha in the same three samples. At the topoisomerase I locus on chromosome 20, we observed allelic loss in two out of 17 samples. Genetics abberations at topoisomerase loci, therefore, appear to be relatively common in breast cancer.

Aged↗
PubMed1990

An evaluation of radiofrequency exposure from therapeutic diathermy equipment in the light of current recommendations.

Shortwave and microwave diathermy equipment use by physiotherapy departments in Grampian Region has been studied. Stray electric and magnetic fields close to equipment have been measured and compared with exposure levels recommended by the INIRC and the NRPB. Fields above the recommended whole body levels extend to 0.5-1.0 m from the electrodes and cables for continuous wave (cw) shortwave equipment, and up to 0.5 m for microwave units and pulsed shortwave models. Operators were exposed to local fields above these values for 2 - 3 min during cw shortwave treatments, but rarely exceeded the recommended exposure. However, short localised exposures to high fields, which can occur if the operator moves close to the electrodes or cables, could exceed these limits. Physiotherapists are advised to remain at a distance of at least 1 m during cw treatments, and not to approach within 0.5 m of the electrodes and cables even for a short period.

Diathermy↗
PubMed1988

Occult primary seminoma: eighteen-year delay in presentation.

Primary retroperitoneal seminoma is well documented. A case is reported in which a patient presented with a seminoma of testis eighteen years after removal of a retroperitoneal seminoma. Histologic appearance of the testis was identified to the original pathology, and it is proposed that this represents recurrence of an occult testicular seminoma.

Adult↗
PubMed1984

Lymphocytic infiltration of the prostate.

Symptomatic presentation due to lymphocytic infiltration of the prostate is rare. Six patients are described in whom lymphocytic infiltration of the prostate was secondary to non-Hodgkin's lymphoma, chronic lymphatic leukaemic, and myeloid leukaemia. The prostatic infiltration was sufficiently extensive to result in outflow tract obstruction.

Aged↗
PubMed1984

Long-term effects of cold cardioplegic myocardial protection in the rat.

The long-term histologic effects of the use of two cold cardioplegic solutions (St. Thomas' and saline) were studied and compared in a model of heterotopic cardiac transplantation in rats of isogeneic strain. After cold cardioplegic arrest, hearts were stored for varying times ("minimal," 30, or 90 minutes) in one of the solution prior to transplantation, giving a total of six groups (five animals in each group). Early assessment of myocardial injury 48 hours after transplantation was by the uptake of technetium 99m pyrophosphate and by measurement of serum creatine kinase activity. Late assessment of myocardial injury at 3 months after transplantation was by quantitative histologic examination. The findings indicated that significant myocardial fibrosis occurred in hearts stored in both solutions for the longest storage period (90 minutes) and that St. Thomas' cardioplegic formula conferred better myocardial protection after 90 minutes' storage than did cold saline, as judged by the degree of histologic injury at 3 months (p less than 0.025). Significant correlation was found between long-term histologic changes at 3 months and the uptake of technetium 99m pyrophosphate (p less than 0.001) and serum creatine kinase activity (p less than 0.05) assessed at 48 hours. Uptake of technetium 99m pyrophosphate and increased serum creatine kinase activity was demonstrated 48 hours after injury in animals having no detectable histologic injury at 3 months. These observations indicate that there may be technetium 99m pyrophosphate uptake and enzyme release from reversibly damaged myocardial cells.

Animals↗