Clonogenic assays under either anchorage-dependent or -independent conditions are very useful for testing the sensitivity of tumor cells to cytotoxic drugs and radiation. These assays have not been widely used with squamous-cell carcinomas (SCC) because of poor tumor-cell viability and poor cloning efficiency, especially in semi-solid media. To find a clonogenic assay suitable for use with human squamous cancers we tested SCC lines, derived in our laboratory from patients with head and neck cancer, for the capacity to form colonies in soft agar and in 96-well plates. Of 13 UM-SCC lines tested for colony formation in agarose, only UM-SCC-11A was capable of growth in conventional semi-solid media. One other line, UM-SCC-14C, produced colonies in agarose only in the presence of epidermal growth factor. In contrast, all 17 of the SCC lines tested exhibited colony formation in adherent cell culture using limiting dilution in 96-well plates. The plating efficiencies of the SCC lines in the 96-well plate assay ranged from 0.02 to 0.52 colonies (wells)/cell whereas the PE values in soft agar were lower, ranging from 0.0055 to 0.0086 colonies/cell. The 96-well plate assay is not affected by cell migration, a problem encountered with some cell lines when clonogenic assays are performed in Petri dishes. UM-SCC-11A was tested for radiation sensitivity both in soft agar and in the 96-well plate assay. Comparable results were obtained. In summary, the majority of SCC cell lines did not form viable colonies in soft agar but the 96-well plate assay was applicable to a broad spectrum of anchorage-dependent human SCC cell lines and provides an efficient method for evaluating clonogenic cell survival.
Calcium antagonists represent a new class of drugs, which were suggested to act by a selective inhibition of Ca2+ influx through cell membranes. We studied the mechanism of action of three calcium antagonists, diltiazem, nifedipine, and verapamil, by investigating the effect on 45Ca uptake and efflux in rat heart and aorta and in rabbit vessels. The uptake of La3+-resistant 45Ca was not decreased by nifedipine or verapamil either in the heart or in the vessels and was increased by diltiazem in rabbit vessels. The efflux of 45Ca from the mesenteric vein of rabbit, originating presumably from intracellular and membrane-boudn fractions, was enhanced by nifedipine. These effects were observed with drug concentrations inhibiting contractions in isolated atria and the spontaneous and norepinephrine-, potassium-, or barium-induced contractions in the portal vein of rats. Thus, our results suggest that calcium antagonistic drugs act by other mechanisms than the inhibition of transmembranous Ca flux, probably on the release and binding of Ca2+ in intracellular pools. The relatively greater inhibition of norepinephrine- than K+-induced contractions in vessels by the calcium antagonistic drugs and the abolition of the inotropic effect of norepinephrine in rat atrium exposed to 0-Ca Krebs solution for a short period are other effects suggesting an intracellular action for these drugs.
Physicians are supportive of the value of screening, however the reliability of and evidence to support DRE and PSA as prostate cancer screening tests are in question. CME which addresses issues surrounding prostate screening and areas related to patient education and counselling are of greatest need.
The impact of breast cancer on the emotional and social health of women and their families is an important issue for the cancer field. Nevertheless, many patients do not avail themselves of support programmes. In rural communities there is often a lack of services, which, for many, leads to a perception of 'being alone' in the struggle to become better. This paper reports an evaluation of a pilot project to facilitate a self-help peer support group network: an extensive provincial audio teleconferencing network for rural breast cancer survivors, established by the Telemedicine Centre of the Memorial University of Newfoundland. A satisfaction questionnaire was distributed to participants in the pilot programme. Responses suggested that they were very satisfied with the use of audio teleconferencing for the facilitation of a social support programme. The programme appeared to help bridge the isolation gap that rural women with breast cancer often experience. The results have implications for the provision of self-help social support services through audio teleconferencing, as well as for the quality of life and wellbeing of rural women.
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