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Biomedical subjects

S C Smith

Publications and source records attributed to S C Smith.

At least 73 records · Page 4Linked to original sources
PubMed1999

Residues within the HFRIGC sequence of HIV-1 vpr involved in growth arrest activities.

HIV-1 Vpr is a virion-associated protein that can cause growth arrest when produced inside the cell but when added externally it can cause cell death. Employing the yeast model system, the C-terminal domain, in particular the sequence HFRIGCRHSRIG (Vpr(71-82)), is essential for both the growth arrest and cytocidal activities. Conservation of this sequence in HIV-2 and SIV suggests that these residues may be functionally important. Using site-directed mutagenesis we show that the most highly conserved aa residues, His71 and Gly75, were important for the cell cycle inhibitory effects. In contrast, we show that the wild-type Vpr(71-82) peptide and three variants of this peptide with Gly75 changed to Ser, Ala, and Ile all exhibited the same cytocidal activity suggesting that the intracellular and extracellular effects are unrelated.

Amino Acid Sequence↗
PubMed1999

Bacterial expression of the major antigenic regions of porcine rotavirus VP7 induces a neutralizing immune response in mice.

The outer capsid protein of rotavirus, VP7, is a major neutralization antigen. A chimeric protein comprising Escherichia coli (E. coli) outer membrane protein A (OmpA) and part of porcine rotavirus VP7 containing all three antigenic regions (217 amino acids) was expressed in Salmonella and E. coli as an outer-membrane associated protein. Mice immunized intraperitoneally or orally, respectively, with live E. coli or Salmonella cells expressing this chimeric protein produced antibodies against native VP7 as determined by enzyme-linked immunosorbent assays and neutralization tests. This indicates that the VP7 fragment from a porcine rotavirus which is antigenically similar to human rotavirus serotype 3, when expressed in bacteria as a chimeric protein, can form a structure resembling its native form at least in some of the major neutralization domains. These results indicate that the use of a live bacterial vector expressing rotavirus VP7 may represent a strategy for the development of vaccines against rotavirus-induced diarrhoea in infants.

Animals↗
PubMed1999

Analysis of the degree of undertreatment of hyperlipidemia and congestive heart failure secondary to coronary artery disease.

There is a lack of data evaluating the implementation of guidelines in the management of coronary artery disease (CAD) or congestive heart failure (CHF) in the outpatient setting. We analyzed an administrative data set from the Merck & Co. sponsored national Quality Assurance Program, a retrospective outpatient chart audit of 58,890 adult outpatients from 140 medical practices (80% cardiology only) in the USA with diagnoses of CAD and/or CHF identified from medical claims data. We determined the (1) frequency of lipid documentation and prescription of lipid-lowering agents in patients with CAD, (2) frequency of assessment of left ventricular function and prescription of an angiotensin-converting enzyme inhibitor in patients with CHF, and (3) predictors of medication prescription. Of the 48,586 patients with CAD, 44% had annual diagnostic testing of low-density lipoprotein cholesterol. Only 25% of these patients reached the target low-density lipoprotein cholesterol of < or = 100 mg/dl, and only 39% were taking lipid-lowering therapy, which was less among the elderly than in the younger patients. Of the 16,603 patients with CHF, 64% had diagnostic testing of left ventricular function, and 50% of patients were taking an angiotensin-converting enzyme inhibitor; 67% of patients received medication if they had documented systolic dysfunction. Significant predictors of medication prescription included diagnostic testing, younger age, history of myocardial infarction or coronary artery bypass grafting, hypertension, cardiology specialty, and geographic region. Thus, current practice patterns in the management of CAD and CHF are inadequate. Patient age, diagnostic testing, and practice environment influence medication prescription.

Adult↗
PubMed1999

Effect of estrogen replacement therapy on corrected thrombolysis in myocardial infarction frame count.

The effect of chronic estrogen replacement therapy on the corrected Thrombolysis In Myocardial Infarction trial frame count of the left anterior descending coronary artery was assessed in 122 postmenopausal women. With use of multivariate analysis to account for confounding variables likely to affect the corrected Thrombolysis In Myocardial Infarction trial frame count, no chronic effect of estrogen replacement therapy on coronary blood flow was documented.

Aged↗
PubMed1999

Reduction in ischemic vascular complications with a hydrophilic-coated intra-aortic balloon catheter.

Hydrophilic coatings improve the handling characteristics of angioplasty equipment, but until recently this technology has not been available for intra-aortic balloon (IAB) catheters. To determine whether a new hydrophilic coating is associated with a reduction in IAB-related complications, we prospectively evaluated 188 patients undergoing insertion of this new IAB catheter. Complications related to IAB insertion were recorded and compared to data from 682 patients previously treated with an uncoated IAB catheter of the same shaft diameter and balloon size. By multivariate analysis the hydrophilic-coated IAB catheter was associated with a 72% reduction in ischemic vascular complications (relative risk 0.28, 95% CI 0.08-0.96, P= 0.04). There were also trends toward reductions in IAB rupture and the need for vascular surgical repair for bleeding or ischemia. While further investigation is warranted, hydrophilic coatings that reduce the coefficient of friction during IAB catheter insertion may also reduce subsequent ischemic vascular complications.

Aged↗
PubMed1999

How the health care system can influence cardiovascular disease risk factors.

Only a small fraction of the health-care dollar is directed toward lifestyle changes that would reduce the social burden from cardiovascular diseases (CVD). Here we discuss the challenge, opportunity, methods, and potential for managed care to implement risk reduction strategies and preventive care. A systematic team approach involving nurses, nutritionists, exercise physiologists, and behavioral experts has been shown to be effective, along with physicians, in reducing CVD risk. This approach is increasingly accepted by and practiced in the CVD community and the managed care industry.

Cardiovascular Diseases↗
PubMed1999

Ejection fraction by radionuclide ventriculography and contrast left ventriculogram. A tale of two techniques. SAVE Investigators. Survival and Ventricular Enlargement.

OBJECTIVES: We assessed the abilities of two methods to measure ejection fraction (EF)-radionuclide ventriculography (RVG) and contrast left ventriculography (Cath-EFa) to predict cardiovascular events. BACKGROUND: Both RVG and Cath-EFa are commonly used methods to measure left ventricular performance and assess prognosis. Their comparative abilities to predict clinical events have not been reported. METHODS: Both RVG EF and Cath-EFa were measured within 16 days of myocardial infarction (MI) in 688 patients. The results were divided into terciles. Prognosis by terciles was assessed for each technique. A multivariate analysis was performed to determine which EF measurement was a better predictor of prognosis. RESULTS: Average RVG-EF was 32%+/-7, while Cath-EFa was 42%+/-10. Both RVG and Cath-EFa were poorly correlated (R=0.42). Event rate declined across terciles with increasing EF for both techniques (events in lowest to highest tercile of Cath-EFa 40.7%, 25.9%, 11.6%, p < 0.001; and RVG-EF 39.9%, 26.1%, 15.6%, p < 0.001). There was concordance of terciles in 303 of 688 patients (44%). When patients in the highest RVG terciles were in the highest Cath-EFa tercile, the event rate was 7%. However, when patients in the highest RVG terciles were in the lowest Cath-EFa tercile, the event rate was 19%. Both Cath-EFa (p < 0.001) and RVG-EF (p < 0.001) were independent predictors of cardiovascular events. CONCLUSIONS: Ejection fraction measured by RVG or during catheterization is a valuable tool in the risk stratification of postinfarct patients. When disagreement is present between clinical impression and measurement by either method, the use of an alternative measurement is warranted and complementary.

Adult↗