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Biomedical subjects

S M Henry

Publications and source records attributed to S M Henry.

42 records · Page 3Linked to original sources
PubMed1987

Use of Fab anti-IgG in phenotyping IgG-sensitised red cells.

Previously described methods of phenotyping red cells sensitised with IgG using the indirect antiglobulin test required the dissociation of the coating protein. Based on an entirely different principle, Fab fragments of anti-human IgG (Fab anti-IgG) were used to block the antiglobulin binding sites on cell-bound IgG molecules, removing the necessity to dissociate them from the red cell. Fab anti-IgG was found to be effective in blocking interfering IgG on in vivo and in vitro IgG-sensitised red cells, permitting successful red cell phenotyping. Strongly IgG-sensitised samples which could not be fully neutralised by chloroquine diphosphate (CDP) or blocked with Fab anti-IgG alone could usually be phenotyped using a combination of both these methods. This new procedure may be of use in immunohaematology laboratories.

Antibodies, Anti-Idiotypic↗
PubMed1983

Nuclear matrix: a cell-cycle-dependent site of increased intranuclear protein phosphorylation.

Evidence is presented that the nuclear matrix is a cell-cycle-dependent site of increased intranuclear protein phosphorylation. The incorporation of radioactive phosphate (32P) is highest during the premitotic (G2) phase and 40-50% less in the postmitotic phase (G1). This is observed for both total matrix protein and for several individual polypeptides ranging in molecular mass from greater than 200 kDa to 19 kDa. The phenomenon can be demonstrated when the matrix is isolated from orthophosphate-labeled intact cells, as well as when the matrix is isolated and then incubated in vitro in a protein kinase reaction mixture. The ability of the isolated matrix to mimic the events in vivo indicates the presence of endogenous protein phosphokinase activity and physiological substrates in this isolated nuclear fraction. Further evidence for such mimicry was obtained when amino acid phosphorylation sites were determined. Phosphoserine is the most abundant phosphoamino acid in the matrix labelled both in vitro and in vivo, although phosphothreonine and phosphotyrosine are also present. On the basis of several pieces of data, the endogenous matrix activity appears to be due to multiple protein phosphokinases. Since the maximum phosphorylation coincides with premitosis, the phosphoproteins may play a role in mitotic events. These observations extend and expand the application of this fraction to the study of nuclear structure/function relationships, particularly at the time of mitosis.

Binding Sites↗
PubMed1983

Evidence for a unique profile of phosphatidylcholine synthesis in late mitotic cells.

Evidence is presented that the structural rearrangements in late mitosis are accompanied by an alteration in membrane lipid synthesis. This evidence was derived from analyzing phospholipid classes after rapid-labeling, as well as from determining the intracellular site of incorporation of choline by HeLa S3 cells as they progressed from metaphase into early interphase (G1). Compared with postmitotic cell data, the recent mitotic cell data indicate a specific two- to threefold increase in the net synthesis of phosphatidylcholine (PC) species, which appeared to contain the more saturated fatty acids. Since this was observed with glycerol, choline, and orthophosphate labelings, and not with methyl labeling, it appears that the CDP-choline plus diacylglycerol pathway rather than the phosphatidylethanolamine to PC pathway was augmented. Electron microscope autoradiography of anaphase, telophase, and early G1 cells demonstrated that the reformed nuclear envelope was the incorporation site of a significant proportion of the newly synthesized PC. This incorporation occurred by early telophase prior to chromosome decondensation. The potential significance of PC metabolism with regard to membrane rearrangements, such as nuclear envelope reformation, is discussed.

Choline↗