PubMed Health⌕ Search

Biomedical subjects

D Guy

Publications and source records attributed to D Guy.

27 records · Page 2Linked to original sources
PubMed1980

Surface properties of cells isolated from non-metastasizing and metastasizing hamster lymphosarcomas.

Present evidence suggests that the cell surface has an important role in metastasis. To examine this idea further, the surface properties of single cells isolated from the primary growths of a liver-metastasizing (ML) and a non-metastasizing (NML) lymphosarcoma were compared for adhesion to cell monolayers, cytopherometry, isoelectric focusing, adhesion to immobilized lectins and surface labelling with lactoperoxidase-catalysed radioiodination. It was found that the ML cells had increased adhesion to 3 out of 4 of the monolayers studies; a lower overall surface charge but greater peripheral concentrations of charge; and increased surface expression of the fucose moiety. No consistent difference between the two cell types was detected in the electrophoretic pattern of the labelled surface proteins. These findings are discussed in the light of present knowledge of the cell surface, and it is concluded that the significance of any of the observed changes in relation to metastasis has yet to be established.

Animals↗
PubMed1979

Surface protein distributions in cells isolated from solid tumours and their metastases.

Methods have been developed which isolate single viable cells from the primary growths of two tumour systems (a lymphosarcoma and a carcinoma) and their secondary deposits. Subsequent comparisons of the surface-membrane structure of pairs of these primary and secondary cells, using lactoperoxidase-catalysed radioiodination coupled with polyacrylamide-gel electrophoresis, suggest that their overall structures are qualitatively very similar. This latter picture is still maintained when the isolated cells are treated with trypsin or incubated in complete medium before radioiodination. Analysis of the incorporated label into defined sections of the electrophoretic patterns revealed small quantitative differences between primary and secondary cells. In particular, slightly reduced incorporation into certain surface components of secondary cell preparations was seen. However, these did not occur for all the animals investigated, and also they did not consistently occur if the isolated cells were incubated in complete medium. The most similar overall change observed for the two tumour systems was a slight reduction in the secondary cells of a 20K mol. wt surface component.

Animals↗
PubMed1979

A simple lectin-mediated cell-adhesion method for investigating the cell surface.

A very simple, rapid and reproducible method has been developed for studying the interaction of lectins with the cell surface. This involves determining the number of adherent cells after shaking cell suspensions in Petri dishes which have had a lectin coupled to their surface using 1-cyclohexyl-3-(2-morpholinoethyl) carbodiimide metho-p-toluene sulfonate. Using concanavalin A coupled to 60 mm diameter dishes and between 1.5 and 2 x 10(6) tumour cells, this adhesion reached a maximum after 10 min shaking. Maximum cell adhesion also varied according to the particular lectin used. Adhesion was absent or was very low if cells were shaken in untreated dishes, or in dishes coupled to bovine serum albumin, or in the presence of the lectin-specific sugar-competitor. Under conditions of maximum cell adhesion, the binding of two different lymphosarcoma lines to four different lectins was very similar, whereas the binding of a carcinoma line to these lectins was completely different from that observed for the lymphosarcomas.

Animals↗
PubMed1977

Radioiodination studies of tumour cell-surface proteins after different disaggregation procedures.

The surface of single cells isolated from solid tumours by either a mechanical or an enzymatic method have been compared, using lactoperoxidase-catalyzed radioiodination of the tyrosine-containing proteins. Qualitatively, the patterns of surface labelling were similar, and duplicate experiments indicated that each method of isolation gave reproducible results. Analysis of incorporated label into 4 defined sections of the electrophoretic pattern illustrated quantitative differences. When the cells were isolated mechanically, the incorporation into low-mol.- wt. components was considerably reduced, whereas that into the high-mol.-wt. components was unaffected. Treatment of enzymatically isolated cells with trypsin also reduced incorporation into low-mol.-wt components.

Animals↗
PubMedDate not supplied

Nitrogen utilization from elemental diets.

Repletion experiments were performed in malnourished, chair-adapted primates to explore recently reported differences in nitrogen utilization from elemental diets. Two elemental diets were fed consecutively for 8 days through a gastrostomy. Diet C (maltodextrins, peptides, crystalline amino acids) resulted in: larger weight gain (F1,6 = 17.93, p less than 0.01); smaller decrease of serum albumin (F1,5 = 11.2, p less than 0.015), larger increase in total iron binding capacity (F1,6 = 30.6, p less than 0.002), and a more positive nitrogen balance (F1,6 = 30.4, p less than 0.002) than diet V (glucose oligosaccharides, crystalline amino acids). Diet C was considered to be more effective in the nutritional repletion of the study animals. Additional experiments were performed in normal human volunteers to investigate the metabolic fate of ingested glutamine and whether the rapid catabolism and excretion of the amido nitrogen of this amino acid, which constitutes 11.56% of total nitrogen in diet V, could explain the differences observed in primates in our study and in human subjects by other authors. Six normal volunteers were fed 15N amino glutamine, 15N alanine, or 15N H4Cl. Similar amounts of 15N from Gln and Ala were excreted in 10 hr. The amido group of glutamine does not seem to be metabolized differently from the alpha-amino group of alanine under the conditions of the study. The marked differences in nitrogen utilization from the study diets could not be explained by the presence of relatively large amounts of glutamine in one of them.

Adult↗
PubMedDate not supplied

[Vasectomy in Quebec: 1977-1997].

Vasectomy is recognized as an efficient method of contraception. However, some recent findings have suggested that vasectomy may raise a potential health risk, notably related to prostate cancer. The goal of the present study is to evaluate the spatial and temporal evolution of this surgical practice in Québec (Canada). Using the registry of the Régie de l'assurance-maladie du Québec, we describe the course of vasectomy practice during the past 21 years. We also estimate the frequency of vasectomy procedures on the regional scale. Observed and expected rates of vasectomy and a synthetic index of vasectomy allow us to evaluate its spatial and temporal evolution. The results show a similar annual growth rate of this practice during the last 10 years. The mean age at the time of vasectomy of the study subjects (N = 332,000) is 35 years old. However recently, this mean age seems to be more representative because of the lower proportions of younger (< 25 years old) and older (> 50 years old) patients at the time of vasectomy. In addition, we observe some clear differences concerning the vasectomy rates between specific geographical sectors; the rates being significantly lower (p < 0.01) in urban and some rural areas. The highest rates are found in the suburbs of Montréal and Québec City. There are also some local variations of the practice, which are difficult to interpret. In this article, we compare our results to those for the rest of Canada and the United States. We note that the rates are generally similar to those for the Province of Québec. Besides, we discuss about the reasons for strong spatial variations of the surgery.

Adult↗