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Biomedical subjects

E R Smith

Publications and source records attributed to E R Smith.

At least 55 records · Page 3Linked to original sources
PubMed2000

Differences in ventricular septal motion between subgroups of patients with heart failure.

BACKGROUND: Septal systolic motion is determined by the end-diastolic trans-septal pressure gradient, and hence is load dependent. OBJECTIVE: To explore septal contribution to left ventricular (LV) systolic function in patients with heart failure. DESIGN: Echocardiograms were identified post hoc from normal subjects and a cohort of patients with heart failure. PATIENTS: Twelve normal subjects and 69 patients with heart failure and normal conduction or left bundle brance block (LBBB) were studied. METHODS: Parasternal short axis LV end-diastolic and end-systolic areas were traced. Using a floating centroid, 32 radial chords were constructed, and perecentage shortening from end-diastole to end-systole was calculated for each chord. MAIN RESULTS: Comparing heart failure with normal conduction and LBBB, LV end-diastolic area was similar (43+/-10 versus 45+/-12 cm(2) not significant), but stroke area was higher in normal conduction (7+/-4 versus 4+/-4cm(2), P<0.05) as was area ejection fraction (0.17+/-0.11 versus 0.10+/- 0.08, P<0.01). In normal subjects, the summed percentage shortening of 10 midseptal chords was similar to that of 10 midfreewall chords (256+/-16% versus 235+/-32%, not significant). In contrast, patients with heart failure and normal conduction had greater midseptal than midfreewall sum med chord shortening (113+/-18% versus 60+/-12%, P<0.05); patients with heart failure and LBBB had paradoxical septal motion (3+/-28, P<0.05 compared with normal conduction). CONCLUSIONS: Patients with heart failure and normal conduction have an enhanced septal contribution to LV systolic function compared with normal subjects. In heart failure with LBBB, this is lost and the area ejection fraction is lower. Strategies to optimize septal function in heart failure warrant further study.

Adult↗
PubMed1999

The adipocyte fatty acid-binding protein binds to membranes by electrostatic interactions.

The adipocyte fatty acid-binding protein (AFABP) is believed to transfer unesterified fatty acids (FA) to phospholipid membranes via a collisional mechanism that involves ionic interactions between lysine residues on the protein surface and phospholipid headgroups. This hypothesis is derived largely from kinetic analysis of FA transfer from AFABP to membranes. In this study, we examined directly the binding of AFABP to large unilamellar vesicles (LUV) of differing phospholipid compositions. AFABP bound LUV containing either cardiolipin or phosphatidic acid, and the amount of protein bound depended upon the mol % anionic phospholipid. The K(a) for CL or PA in LUV containing 25 mol % of these anionic phospholipids was approximately 2 x 10(3) M(-1). No detectable binding occurred when AFABP was mixed with zwitterionic membranes, nor when acetylated AFABP in which surface lysines had been chemically neutralized was mixed with anionic membranes. The binding of AFABP to acidic membranes depended upon the ionic strength of the incubation buffer: >/=200 mM NaCl reduced protein-lipid complex formation in parallel with a decrease in the rate of FA transfer from AFABP to negatively charged membranes. It was further found that AFABP, but not acetylated AFABP, prevented cytochrome c, a well characterized peripheral membrane protein, from binding to membranes. These results directly demonstrate that AFABP binds to anionic phospholipid membranes and suggest that, although generally described as a cytosolic protein, AFABP may behave as a peripheral membrane protein to help target fatty acids to and/or from intracellular sites of utilization.

Adipocytes↗
PubMed1999

Identification of ammonium ion and 2,6-bis(omega-aminobutyl)- 3, 5-diiminopiperazine as endogenous factors that account for the "burst" of sphingosine upon changing the medium of J774 cells in culture.

Cells in culture often undergo a "burst" of free sphingosine, sphingosine 1-phosphate, ceramide, and other bioactive lipids upon removal of "conditioned" medium, and at least one lipid signaling pathway (protein kinase C) has been shown to be affected by these changes (Smith, E. R. & Merrill A. H., Jr. (1995) J. Biol. Chem. 270, 18749-18758; Smith, E. R., Jones, P. L., Boss, J. M. & Merrill, A. H., Jr. (1997) J. Biol. Chem. 272, 5640-5646). Whereas increases in sphinganine and dihydroceramide are responses to provision of precursors for sphingolipid biosynthesis de novo in the new medium, the sphingosine burst is due to sphingolipid turnover upon removal of suppressive factor(s) in conditioned medium. This study describes the purification and characterization of these suppressive factors. Conditioned medium from J774 cells was fractionated into two components that suppress the burst as follows: ammonium ion, which reaches 2-3 mM within 48 h of cell culture; and a low molecular weight, cationic compound that has been assigned the structure 2, 6-bis(omega-aminobutyl)-3,5-diimino-piperazine (for which we suggest the name "batrachamine" based on its appearance) by (1)H and (13)C NMR, Fourier transform infrared spectroscopy, and mass spectrometric analyses. The physiological significance of these compounds as suppressors of sphingolipid metabolism is unclear; however, ammonium ion is a by-product of amino acid catabolism and reaches high concentrations in some tissues. Batrachamine is even more intriguing because this is, as far as we are aware, the first report of a naturally occurring compound of this structural type. Considering the many cell functions that are affected by sphingoid bases and their derivatives, the effects of NH(4) and batrachamine on sphingolipid metabolism may have important implications for cell regulation.

Ammonium Chloride↗
PubMed1999

Revisiting the past and back to the future: memory systems and the linguistic representation of social events.

Five studies were conducted to investigate the relationship between how people communicate about social events and how representations of these events are stored in memory. It was hypothesized that more distant events in memory would be described with more abstract linguistic predicates, and recent events with more concrete language. The 1st study supported this hypothesis. The 2nd and 3rd experiments demonstrated that abstract predicates used as prompts elicit memories that are significantly more removed in time than concrete predicates. Two final experiments showed that these outcomes are not merely a function of the type of semantic cue but an interaction between memory and preferential predicate use. The findings illustrate a link between memory and communicative behavior of a type that has not been previously studied. The results are discussed in terms of a recent, well-supported model of 2 separate fast-learning and slow-learning memory systems.

Affect↗
PubMed1999

Attachment to groups: theory and measurement.

Aspects of people's identification with groups may be understood by borrowing theoretical ideas and measurement strategies from research on attachment in close relationships. People have mental models of the self as a group member and of groups as sources of identity and esteem. These models affect thoughts, emotions, and behaviors related to group membership. Three studies show that two dimensions of attachment to groups, attachment anxiety and avoidance, can be assessed with good reliability, validity, and over-time stability. These factors are distinct from relationship attachment and from other measures of group identification. Group attachment predicts several important outcomes, including emotions concerning the group, time and activities shared with a group, social support, collective self-esteem, and ways of resolving conflict. This conceptualization provides new insights into the nature of people's psychological ties to groups.

Adult↗
PubMed1999

Seeking a comprehensive vision plan.

The demand for vision care services continues to rise rapidly. A comprehensive vision benefit can be of tremendous value to the employer and employee alike. Although nationwide standards do not exist for the provision of vision care services, the authors outline the features of a vision benefit that are crucial to offering a quality plan.

Costs and Cost Analysis↗
PubMed1999

Oncogene expression and microvessel count in recurrent and nonrecurrent stage Ib squamous cell carcinoma of the cervix.

OBJECTIVE: To evaluate p53, epidermal growth factor receptor (EGFR) and c-erbB-2 oncogene expression and compare it with microvessel count (MVC) in determining the clinical outcome of stage Ib squamous cell carcinoma (SCC) of the cervix. STUDY DESIGN: Immunostaining with p53, EGFR, C-erbB-2 and factor VIII antibodies was performed on tumor sections from 22 patients (11 with cancer recurrence, 11 free of cancer after four years). The levels of oncogene expression were semiquantitatively graded (0-4). Microvessels were counted (per 200 x field) in areas of highest neovascularization. RESULTS: Eight of 11 patients (72.7%) with recurrence expressed EGFR as compared with 5 of 11 patients (45.5%) free of disease. This difference is not significant (P = .39). An equal number of patients with and without recurrence expressed c-erbB-2. Five of 11 patients (45.5%) with recurrence expressed p53, as compared with 6 of 11 (54.5%) free of disease (P = 1.00). Eight of 11 patients (72.7%) with recurrence had an MVC above 24 as compared with 2 of 11 patients (18.2%) free of disease; this difference was statistically significant (P = .03). CONCLUSION: The expression of EGFR, p53 and c-erbB-2 appears to have little prognostic value in stage Ib SCC of the uterine cervix. The prognostic value of MVC is in keeping with previous findings.

Adult↗
PubMed1998

Cloning of Drosophila GCN5: conserved features among metazoan GCN5 family members.

PCAF and hGCN5 are distinct human genes that encode proteins related to the yeast histone acetyltransferase and transcriptional adapter GCN5. The PCAF protein shares extensive similarity with the 439 amino acids of yGCN5, but it has an approximately 350 amino acid N-terminal extension that interacts with the transcriptional co-activator p300/CBP. Adenoviral protein E1a can disrupt PCAF-CBP interactions and prevent PCAF-dependent cellular differentiation. In this report, we describe the cloning and initial characterization of a Drosophila homolog of yGCN5. In addition to the homology to yGCN5, the Drosophila protein shares sequencesimilarity with the N-terminal portion of human PCAF that is involved in binding to CBP. In the course of characterizing dGCN5, we have discovered that hGCN5 also contains an N-terminal extension with significant similarity to PCAF. Interestingly, in the case of the h GCN5 gene, alternative splicing may regulate the production of full-length hGCN5. The presence of the N-terminal domain in a Drosophila GCN5 homolog and both human homologs suggests that it was part of the ancestral form of metazoan GCN5.

Acetyl-CoA C-Acyltransferase↗