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T Parsons

Publications and source records attributed to T Parsons.

32 records · Page 2Linked to original sources
PubMed1992

High-affinity binding of the bactericidal/permeability-increasing protein and a recombinant amino-terminal fragment to the lipid A region of lipopolysaccharide.

Bactericidal/permeability-increasing protein (BPI) is a 55-kDa cationic protein (nBPI55) elaborated by polymorphonuclear neutrophils (PMN). BPI has potent bactericidal activity against a wide variety of gram-negative organisms and neutralizes endotoxin activities. An N-terminal fragment of nBPI55 exhibits the bactericidal and antiendotoxin properties of the holoprotein. To further characterize the biological activities of the N-terminal fragment, a recombinant protein (rBPI23) corresponding to the first 199 amino acids of human BPI was produced and purified. rBPI23 had antibacterial activity equivalent to that of nBPI55 against Escherichia coli J5. Furthermore, both rBPI23 and nBPI55 bound identically to a broad range of R- and S-form lipopolysaccharides (LPS) and to natural and synthetic lipid A. Binding of radiolabeled nBPI55 to LPS was inhibited in an identical fashion by either nBPI55 or rBPI23. The binding of both proteins to immobilized E. coli J5 lipid A was inhibited in a comparable fashion by long- or short-chain LPS or lipid A. The binding of both rBPI23 and nBPI55 was specific, saturable, and of high affinity, with an apparent Kd of approximately 2 to 5 nM for all ligands tested. These results demonstrate that BPI recognizes the highly conserved lipid A region of bacterial LPS via residues contained within the amino-terminal portion of the BPI molecule.

Antimicrobial Cationic Peptides↗
PubMed1990

Effects of norepinephrine on neonatal rat cardiocyte growth and differentiation.

Norepinephrine stimulates the growth in size of nondividing neonatal cardiocytes. During this time the neonatal cardiocyte is in a period of transition in which the cell can synthesize DNA and yet does not divide. Because the cell undergoes karyokinesis without cytokinesis the objective of this study was to determine whether the norepinephrine-induced growth in size of the neonatal cardiocyte was accompanied by an increase in a) the number of cardiocytes synthesizing DNA, b) the number of binucleate cardiocytes, and c) organized myofibrils. One- to four-d-old neonatal rat heart cells were isolated and placed in serum-free medium which was then supplemented with serum, norepinephrine, norepinephrine plus propranolol, or isoproterenol. After 4 d the number and size of the cells was determined using a Coulter counter. In other cultures cardiocytes were fixed on Days 0, 1, 2, and 4, and an increase in the number of binucleate cardiocytes was found in all treatment groups including controls. However, the rate of binucleation was faster in the norepinephrine group. It was also determined by proliferating cell nuclear antigen (PCNA) antibody staining that by Day 4, over 50% of the cardiocytes were in the cell cycle. The percentage of cells in which PCNA could be detected was higher in the norepinephrine and norepinephrine plus propranolol groups. Furthermore, there was a concomitant increase in the amount and organization of myofibrils in the catecholamine-treated cardiocytes.

Animals↗
PubMed1988

Electrophysiology versus psychophysics in the detection of visual loss in pseudotumor cerebri.

This study compared visual evoked potentials (VEP) and contrast sensitivity (CS) as methods of detecting visual loss in 15 women with acute onset of pseudotumor cerebri (PTC). A total of 24 out of 30 eyes (14 of 15 patients) had a visual disturbance. Neuro-ophthalmologic examination demonstrated abnormal Goldmann visual fields in 13 of 30 eyes. CS was abnormal in 18 eyes; VEP was abnormal in five eyes. Nine eyes had visual loss detected by CS only, five by perimetry only, and one had the VEP as the sole abnormality. CS was a valuable adjunct to perimetry in PTC whereas VEP was rarely helpful.

Adolescent↗
PubMed1981

Metabolic labeling of lutropin with [35S]sulfate.

Chemical analyses have previously detected sulfate linked to the oligosaccharides of lutropin isolated from bovine and human pituitaries. To determine whether lutropin could be metabolically labeled with sulfate, isolated bovine and rat pituitaries were incubated with [35S]sulfate. In both species, two major labeled products were immunoprecipitated with antisera specific to lutropin subunits. Incorporation into the subunits occurred posttranslationally since it was not blocked by cycloheximide, which did, however, block the incorporation of radiolabeled methionine. Metabolic labeling with [35S]sulfate provides a valuable approach for examining the biosynthetic processing of lutropin and the physiological role of sulfate in this hormone.

Animals↗
PubMed1975

The sick role and the role of the physician reconsidered.

The main substance of this paper was presented orally at a meeting of the Sick Role, organized and chaired by Andrew Twaddle. It was a commentary on four papers and the oral discussion of them. In response to these the paper first discusses the relation of the sick role to deviant behavior and the motivation to become and remain ill. The position was taken that the author never had meant to confine the category of illness to deviant behavior, though its negative valuation should not be forgotten. Nor had he confined it to cases of acute illness, omitting consideration of chronic and other types. The most important issue, however, concerned the structure of the relation between physician and patient. Though insisting that interaction between them is two-way, not one-way, the author insisted that the relation is basically asymmetrical because of the physician's expertise in health matters, gained through training and experience, and his special fiduciary responsibility for the care of the sick. In this respect the relationship is different from others such as the competitive market or the democratic association, but is comparable to the relation of teacher and student in higher education.

Authoritarianism↗
PubMedDate not supplied

Properties of cultured endothelium from adult human vessels.

Endothelium was isolated from samples of aorta and vena cava obtained from cadaver donors at the time kidneys were harvested for transplantation. Digestion with collagenase and gentle swabbing were used to free the cells from the intimal surface. Low density seeding permitted isolation of individual colonies with typical endothelial morphology. Modified Medium 199 supplemented with 10%-20% human plasma-derived serum and an extract from the bovine hypothalamus (500 micrograms/ml) enabled subcultured colonies to grow to confluency when culture surfaces were coated with fibronectin (1 micrograms/cm2). The presence of Factor VIII antigen was demonstrated using an indirect immunofluorescence technique. A monoclonal antibody to cultured umbilical vein endothelium, specific for endothelium, reacted with the subcultured cells from the aorta and vena cava. Type IV procollagen, fibronectin, and thrombospondin were identified as labeled proteins secreted by cultures of adult endothelium that had been incubated with 3H-proline and 3H-glycine. When the cultured endothelium was used in a sodium-m-periodate stimulated T lymphocyte mitogenic culture system, the endothelium exhibited accessory cell function. Prostacyclin production stimulated by incubation with arachidonic acid and PGH2 was variable from vessel to vessel. However, average values were lower than normally seen with cultured primary umbilical vein endothelium.

Adult↗