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Biomedical subjects

P Lyons

Publications and source records attributed to P Lyons.

At least 19 recordsLinked to original sources
PubMed2000

The noncatalytic domain of protein-tyrosine phosphatase-PEST targets paxillin for dephosphorylation in vivo.

The noncatalytic domain of protein-tyrosine phosphatase (PTP)-PEST contains a binding site for the focal adhesion-associated protein paxillin. This binding site has been narrowed to a 52-residue sequence that is composed of two nonoverlapping, weak paxillin binding sites. The PTP-PEST binding site on paxillin has been mapped to the two carboxyl-terminal LIM (lin11, isl-1, and mec-3) domains. Transient expression of PTP-PEST reduced tyrosine phosphorylation of p130(cas), as anticipated. A PTP-PEST mutant defective for binding p130(cas) does not cause a reduction in its tyrosine phosphorylation in vivo. Expression of PTP-PEST also caused a reduction of phosphotyrosine on paxillin. Expression of mutants of PTP-PEST with deletions in the paxillin-binding site did not associate with paxillin in vivo and failed to cause a reduction in the phosphotyrosine content of paxillin. These results demonstrate that paxillin can serve as a PTP-PEST substrate in vivo and support the model that a noncatalytic domain interaction recruits paxillin to PTP-PEST to facilitate its dephosphorylation.

Animals↗
PubMed1999

Effective health promotion and clinical care for large people.

Health and fitness professionals most often approach health care for large people in the context that health improvement can only be attained through weight loss. Unequivocal acceptance of the notion that thinness equals health and fitness presents an obstacle for large people who want to improve their health through lifestyle changes in eating and activity patterns and also weakens the working relationship between the health care professional and the large client. Since the health benefits of exercise and sound nutrition are significant for people of all sizes, the strategy for health care professionals should be to assist people of all sizes in eating healthier and becoming more active. Because large people face even more barriers to exercise than smaller people, we address the special needs of large people trying to become more physically active, outline an approach sensitive to their needs, and suggest how health and fitness professionals can improve their effectiveness with this population.

Body Weight↗
PubMed1998

The construction of the crack babies phenomenon as a social problem.

Early negative findings on cocaine-exposed newborns engendered widespread media and public perceptions of a causal link between poor mothers' substance use and serious problems in their offspring. Despite later research questioning the prevalence of the problems and implicating other environmental and economic factors, these mothers were stigmatized and criminalized, and their children precipitously removed from their care. This paper reviews the process by which this came about and urges a more balanced and complex view of the problem.

Cocaine-Related Disorders↗
PubMed1997

Bet1p activates the v-SNARE Bos1p.

Bet1p is a type II membrane protein that is required for vesicular transport between the endoplasmic reticulum and Golgi complex in the yeast Saccharomyces cerevisiae. A domain of Bet1p, that shows potential to be involved in a coiled-coil interaction, is homologous to a region of the neuronal protein SNAP-25. Here, we used in vitro binding studies to demonstrate that Bet1p plays a role in potentiating soluble NSF attachment protein receptor (SNARE) interactions. Mutational analysis points to the coiled-coil region as necessary for Bet1p function, and circular dichroism experiments support this theory. In vitro binding studies were also used to demonstrate that a direct interaction between Bet1p and Bos1p is required for the efficient interaction of the vesicle SNARE with its SNARE target. Genetic studies suggest that the interactions of Bet1p with Bos1p are regulated by the small GTP-binding protein Ypt1p.

Amino Acid Sequence↗
PubMed1997

The birth.

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Adolescent↗
PubMed1997

The rape.

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Emergency Service, Hospital↗
PubMed1995

Immunogenicity of transgenic plant-derived hepatitis B surface antigen.

The focus of the Children's Vaccine Initiative is to encourage the discovery of technology that will make vaccines more readily available to developing countries. Our strategy has been to genetically engineer plants so that they can be used as inexpensive alternatives to fermentation systems for production of subunit antigens. In this paper we report on the immunological response elicited in vivo by using recombinant hepatitis B surface antigen (rHBsAg) purified from transgenic tobacco leaves. The anti-hepatitis B response to the tobacco-derived rHBsAg was qualitatively similar to that obtained by immunizing mice with yeast-derived rHBsAg (commercial vaccine). Additionally, T cells obtained from mice primed with the tobacco-derived rHBsAg could be stimulated in vitro by the tobacco-derived rHBsAg, yeast-derived rHBsAg, and by a synthetic peptide that represents part of the a determinant located in the S region (139-147) of HBsAg. Further support for the integrity of the T-cell epitope of the tobacco-derived rHBsAg was obtained by testing the ability of the primed T cells to proliferate in vitro after stimulation with a monoclonal anti-idiotype and an anti-idiotype-derived peptide, both of which mimic the group-specific a determinant of HBsAg. In total, we have conclusively demonstrated that both B- and T-cell epitopes of HBsAg are preserved when the antigen is expressed in a transgenic plant.

Amino Acid Sequence↗
PubMed1994

Ypt1p implicated in v-SNARE activation.

Synaptobrevin-like membrane proteins that reside on transport vesicles, called the vesicle SNARE (v-SNARE), play a key role in ensuring that a vesicle targets and fuses with its correct acceptor compartment. Here we show that Bos1p, the v-SNARE of yeast endoplasmic reticulum-to-Golgi transport vesicles, pairs with another integral membrane protein of similar topology (Sec22p) on vesicles. This pairing, which appears to require functional Ypt1p (Rab in mammalian cells), may aid the activity of Bos1p on this compartment. These findings suggest that Rabs regulate the specificity of membrane fusion by selectively activating the v-SNARE on carrier vesicles. Because the v-SNARE resides on more than one membrane, such a regulated activation step may be necessary to prevent the premature fusion of donor and acceptor compartments.

Biological Transport↗
PubMed1988

Production of hepatitis B virus-infected human B-cell hybridomas: transmission of the viral genome to normal lymphocytes in cocultures.

The presence of hepatitis B virus (HBV) genome and transcripts in mononuclear cells from a patient with acute type B hepatitis offered the possibility of developing a cell line which could serve as a model for HBV replication in lymphocytes. A human B-cell hybridoma, KDG92, was then produced which carries HBV DNA in an episomal state and expresses the major virus transcripts as well as its surface (HBsAg), core (HBcAG), and e (HBeAg) antigens. KDG92 releases in the supernatant surface antigen particles but not core or Dane particles. However, in cocultures this hybridoma is able to transmit episomal HBV DNA to normal lymphocytes, both T and B cells. This in vitro system can therefore provide important indications as to the virus life cycle in lymphocytes and the mechanisms of virus propagation from cell to cell.

B-Lymphocytes↗