Search PubMed⌕ Search

Biomedical subjects

A Murphy

Publications and source records attributed to A Murphy.

At least 127 records · Page 7Linked to original sources
PubMed1988

Thrombospondin promotes platelet aggregation.

Thrombospondin (TSP), isolated from human platelets, promotes aggregation of both nonstimulated platelets and platelets stimulated with thrombin or ADP. The TSP-promoted aggregation is specific since a monoclonal antibody against TSP inhibits the effect of exogenously added TSP and inhibits thrombin-induced platelet aggregation in the absence of added TSP. Several lines of evidence suggest that TSP mediates its effect on aggregation of nonstimulated and stimulated platelets through different platelet-surface receptor systems. The TSP-promoted aggregation of nonstimulated platelets was inhibited by a monoclonal antibody to platelet glycoprotein IV (GPIV), but not by a monoclonal antibody to the fibrinogen receptor, GPIIb-IIIa. In contrast, the antibody to GPIIb-IIIa totally inhibited the TSP-potentiated aggregation of thrombin-stimulated platelets, whereas the antibody to GPIV has no effect. Thus, these studies suggest that TSP promotes platelet aggregation by at least two mechanisms--one dependent on and one independent of the platelet fibrinogen receptor system.

Adenosine Diphosphate↗
PubMed1987

Bombesin-like peptides elevate cytosolic calcium in small cell lung cancer cells.

The ability of bombesin-like peptides to elevate intracellular Ca2+ levels in small cell lung cancer cells was investigated using the fluorescent Ca2+ indicator Fura 2. Nanomolar concentrations of bombesin elevated cytosolic Ca2+ levels in the absence or presence of extracellular Ca2+. Potent bombesin receptor agonists, such as gastrin releasing peptide (GRP) or (GRP)14-27 elevated cytosolic Ca2+ levels whereas inactive compounds such as (D-Trp8)bombesin or (GRP)1-16 did not. Furthermore, the bombesin receptor antagonist (D-Arg1, D-Pro2, D-Trp7,9, Leu11) substance P (30 microM) had no effect on the Ca2+ levels by itself but antagonized the increase in Ca2+ caused by 10 nM or 100 nM bombesin. These data suggest that bombesin receptors may regulate the release of Ca2+ from intracellular organelles in small cell lung cancer cells.

Benzofurans↗
PubMed1987

Thrombospondin promotes cell-substratum adhesion.

The physiological role of the platelet-secreted protein thrombospondin (TSP) is poorly understood, although it has been postulated to be involved in platelet aggregation and cellular adhesion. In this report, TSP isolated from human platelets was found to promote, in vitro, the cell-substratum adhesion of a variety of cells, including platelets, melanoma cells, muscle cells, endothelial cells, fibroblasts, and epithelial cells. The adhesion-promoting activity of TSP was species independent, specific, and not due to contamination by fibronectin, vitronectin, laminin, or platelet factor 4. The cell surface receptor for TSP is protein in nature and appears distinct from that for fibronectin.

Animals↗
PubMed1985

Gestation sac size in in-vitro fertilization pregnancies.

The gestation sac size in pregnancies resulting from in-vitro fertilization (IVF) and embryo transfer have been compared with those in spontaneous pregnancies. Small-for-dates gestational sac sizes were found in 36% of the IVF pregnancies. This proportion held for both singleton and multiple pregnancies. With increasing gestation beyond 8 weeks the gestation sac volume increasingly approached normal. In contrast to spontaneous conceptions, IVF pregnancies had a low rate of pregnancy loss once fetal heart movements were demonstrated, when the gestation sac size was small-for-dates. Small sac size in an IVF pregnancy may lead to the misdiagnosis of a failed pregnancy.

Abortion, Spontaneous↗
PubMed1983

Skeletons in the closet: exploring personal family background as a prerequisite for family nursing.

A nurse's family background, values and experiences will either positively or negatively affect the kind of care he or she gives. This depends on whether the nurse either has explored his/her background and uses it as a valuable resource or fails to see that it may affect care or even be a restriction to quality care. An individual can take specific steps to use family background as a potent and valuable resource. This paper describes a collection of self-directed and group exercises developed at the University of British Columbia School of Nursing that can be used to explore family background and hence use it more positively.

Adult↗
PubMed1983

Mutants deleted in the agnogene of simian virus 40 define a new complementation group.

Analysis of the DNA sequence of the late leader region of simian virus 40 indicates that it might encode a 61-amino acid, highly basic protein, LP-1. Mutants deleted in this region are viable, but they produce infectious progeny more slowly than wild-type virus in established monkey cells. On the basis of the rates of appearance and the sizes of mixed plaques formed after cotransfections with pairs of mutants, we found that mutants defective in the synthesis of LP-1 complementation was also observed in infections with virions and was bidirectional. Therefore, these mutants define a new complementation group, group G. In addition, a protein of the appropriate molecular weight for LP-1 (approximately 8 X 10(3) ) was synthesized by wild-type virus-infected cells but not by mock-infected or group G gene mutant-infected cells. This protein, whose identity has been established definitively by Jay et al. (Nature (London) 291:346-349, 1981), was synthesized at a high rate at late times after infection, was present predominantly in the cytoplasmic fraction of cells, possessed a fairly short half-life, and was absent from mature virions. Once formed, virions of group G gene mutants behaved biologically and physically like virions of wild-type virus. On the basis of these findings and other known properties of LP-1 and mutants defective in LP-1 synthesis, we hypothesize that LP-1 functions to facilitate virion assembly, possibly by serving as a nonreusable scaffolding protein.

Animals↗
PubMed1983

An investigation of the optimum culture conditions for a differentiated culture of sheep thyroid cells.

Primary cultures of differentiated sheep thyroid were investigated to assess the effect of varying the media, sera, hormones and the initial cell number plated on the culture life span. Iodide uptake and follicular morphology were used as indices of differentiation. It was found that the effect of variations in the type of medium and the concentration and type of serum used was very small. The addition of all the hormones used - insulin, hydrocortisone and thyrotrophic hormone - had a synergistic effect on the iodide trapping ability of the culture system. A cell number of approximately 1 x 10(6) cells per 25 cm2 flask was found to be optimum for the development of differentiation in the cultures.

Animals↗