Biomedical subjects

R Vlietstra

Publications and source records attributed to R Vlietstra.

8 recordsLinked to original sources

PubMed1997

Analysis of the relative costs and effectiveness of primary angioplasty versus tissue-type plasminogen activator: the Primary Angioplasty in Myocardial Infarction (PAMI) trial. The PAMI Trial Investigators.

OBJECTIVES: We sought to determine the relative cost and effectiveness of two different reperfusion modalities in patients with acute myocardial infarction (AMI). BACKGROUND: Recent studies have found superior clinical outcomes after reperfusion by primary percutaneous transluminal coronary angioplasty (PTCA) compared with thrombolytic therapy. The high up-front costs of cardiac catheterization may diminish the relative advantages of this invasive strategy. METHODS: Detailed in-hospital charge data were available from all 358 patients with AMI randomized to tissue-type plasminogen activator (t-PA) or primary PTCA in the United States from the Primary Angioplasty in Myocardial Infarction trial. Resource consumption during late follow-up was estimated by assessment of major clinical events and functional status. RESULTS: Compared with t-PA, primary PTCA resulted in reduced rates of in-hospital mortality (2.3% vs. 7.2%, p = 0.03), reinfarction (2.8% vs. 7.2%, p = 0.06), recurrent ischemia (11.3% vs. 28.7%, p < 0.0001) and stroke (0% vs. 3.9%, p = 0.02) and a shorter hospital stay (7.6 +/- 3.3 days vs. 8.4 +/- 4.7 days, p = 0.04). Despite the initial costs of cardiac catheterization in all patients with the invasive strategy, total mean (+/- SD) hospital charges were $3,436 lower per patient with PTCA than with t-PA ($23,468 +/- $13,410 vs. $26,904 +/- $18,246, p = 0.04), primarily due to the reduction in adverse in-hospital outcomes. However, professional fees were higher after primary PTCA ($4,185 +/- $3,183 vs. $3,322 +/- $2,728, p = 0.001), and thus total charges, although favoring PTCA, were not significantly different ($27,653 +/- $13,709 vs. $30,227 +/- 18,903, p = 0.21). At a mean follow-up time of 2.1 +/- 0.7 years, no major differences in postdischarge events or New York Heart Association functional class were present between PTCA- and t-PA-treated patients, suggesting similar late resource consumption. Including in-hospital events, 83% of PTCA-treated patients were alive and free of reinfarction at late follow-up, compared with 74% of t-PA-treated patients (p = 0.06). CONCLUSIONS: Compared with t-PA, reperfusion by primary PTCA improves clinical outcomes with similar or reduced costs. These findings have important clinical implications in an increasingly cost-conscious health care environment.

Aged↗

PubMed1997

A novel gene which is up-regulated during colon epithelial cell differentiation and down-regulated in colorectal neoplasms.

To identify new molecular markers for differentiation of normal and neoplastic colon epithelium, we have studied changes in gene expression during the in vitro differentiation of the HT29-D4 colon carcinoma cell line. Using a modified differential display procedure, we cloned a novel cDNA, designated differentiation-related gene 1 (Drg1). Drg1 mRNA has a length of approximately 3 kb and is induced approximately 20-fold during in vitro differentiation of the colon carcinoma cell lines HT29-D4 and Caco-2. The absence of Drg1 induction in growth-inhibited A431 epidermoid carcinoma cells indicates that Drg1 up-regulation in colon carcinoma cells is not a result of decreased proliferation. The Drg1 cDNA contains an open-reading frame of 1182 bp that encodes a protein with a predicted molecular weight of 43 kd. Drg1 mRNA is expressed most prominently in placental membranes and prostate, kidney, small intestine, and ovary tissues. Compared to normal colon mucosa, Drg1 mRNA expression is decreased in colon adenomas and adenocarcinomas. An antiserum raised against recombinant Drg1 protein detected a band of the expected size in Western blots. Immunohistochemistry showed that in normal colon Drg1 protein is expressed in the cytoplasm and basolateral membranes of surface epithelial cells that border the gut lumen, indicating that Drg1 protein is expressed late during differentiation, just before apoptosis and shedding of cells into the colon lumen.

Amino Acid Sequence↗

PubMed1996

Influence of acute myocardial infarction location on in-hospital and late outcome after primary percutaneous transluminal coronary angioplasty versus tissue plasminogen activator therapy.

In the Primary Angioplasty in Myocardial Infarction trial, 395 patients with acute myocardial infarction (AMI) were prospectively randomized to tissue plasminogen activator (tPA) or primary percutaneous transluminal coronary angioplasty (PTCA). In 138 patients with anterior wall AMI, in-hospital mortality was significantly reduced by treatment with PTCA compared with tPA (1.4% vs 11.9%, p = 0.01). PTCA also resulted in lower rates of death or reinfarction (1.4% vs 18.0%, p = 0.0009), recurrent myocardial ischemia (11.3% vs 28.4%, p = 0.01), and stroke (0.0% vs 6.0%, p = 0.037) in anterior wall AMI. The independent beneficial effect of treatment with primary PTCA rather than tPA in anterior wall AMI was confirmed by multivariate analysis and interaction testing. The in-hospital mortality of 257 patients with nonanterior wall AMI was similar after PTCA and tPA (3.2% vs 3.8%, p = 0.82). Compared with tPA, however, primary PTCA resulted in a markedly lower rate of recurrent myocardial ischemia (9.7% vs 27.8%, p = 0.0002), fewer unscheduled catheterization and revascularization procedures, and a shorter hospital stay (7.0 vs 8.6 days, p = 0.01) in nonanterior wall AMI. Thus, compared with tPA, primary PTCA in patients with anterior wall AMI results in significantly improved survival, with lower rates of stroke, reinfarction, and recurrent myocardial ischemia. In nonanterior wall AMI, treatment with PTCA and tPA results in similar early mortality, although PTCA-treated patients have a more stable hospital course characterized by reduced recurrent ischemia, fewer subsequent invasive procedures, and earlier discharge.

Angioplasty, Balloon, Coronary↗

PubMed1996

Outcome of different reperfusion strategies in patients with former contraindications to thrombolytic therapy: a comparison of primary angioplasty and tissue plasminogen activator. Primary Angioplasty in Myocardial Infarction (PAMI) Investigators.

High-risk patients have been excluded from most thrombolytic trials because of concern over hemorrhagic complications or lack of efficacy. However, based on several recent studies suggesting that patients with relative thrombolytic contraindications may also benefit from reperfusion, recommendations have been made to broadly expand the eligibility criteria for thrombolytic therapy, despite higher absolute complication rates. Primary percutaneous transluminal coronary angioplasty (PTCA) may be an attractive alternative for patients presenting at appropriately equipped hospitals who would otherwise remain at high risk after thrombolytic therapy. In the Primary Angioplasty in Myocardial Infarction (PAMI) trial, 395 patients with acute myocardial infarction were randomized to tissue plasminogen activator (t-PA) or primary PTCA. Conditions were present in 151 patients (38%) which formerly would have contraindicated thrombolytic therapy (age > 70 yr, symptom duration > 4 hr, or prior bypass surgery). In-hospital mortality was 4.3-fold higher in patients with former thrombolytic contraindications compared to lytic-eligible patients (8.6% vs. 2.0%, P = .002). Lytic-eligible patients treated with t-PA and PTCA had similar in-hospital mortality (1.7% vs. 2.4%, P = NS). In contrast, both in-hospital (2.9% vs. 13.2%, P = .025) and 6-mo mortality (2.9% vs. 15.7%, P = .009) were significantly reduced in patients with former thrombolytic contraindications treated by primary PTCA compared to t-PA. By logistic regression analysis, treatment by PTCA rather than t-PA was the strongest predictor of survival in patients with former thrombolytic contraindications. We conclude that patients with conditions formerly contraindicating thrombolytic therapy constitute a high-risk group with significant morbidity and mortality after lytic reperfusion. Our data suggest that patients with former contraindications to thrombolytic therapy may benefit by preferential management with primary PTCA without antecedent thrombolysis.

Aged↗

PubMed1996

Initial experience with 1.5-mm2 high impedance, steroid-eluting pacing electrodes.

UNLABELLED: In this human study, 21 atrial and 62 ventricular 1.5-mm2 unipolar steroid-eluting pacing electrodes were implanted in 64 patients. Pacing thresholds, lead impedance, and sensing measurements were measured via pacemaker telemetry within 24 hours postimplant, and at 1, 2, 3, 4, 6, 12, 24, and 52 weeks. Acute pacing impedances measured via a pacing systems analyzer were 1,039 +/- 292 (atrial) and 1,268 +/- 313 ohms (ventricular). A 10%-15% decline in the mean telemetered atrial and ventricular pacing impedances was observed at 1 week, but thereafter remained stable. Acute pacing thresholds at 0.5 ms were 0.5 +/- 0.3 V (atrial) and 0.4 +/- 0.1 V (ventricular). Filtered P and R wave amplitudes were 3.7 +/- 2.3 mV and 14.9 +/- 5.9 mV, respectively. In 21 patients, no complications related to the atrial electrode were observed. Of 62 patients with ventricular electrodes, 4 patients (6%) experienced complications and required surgical intervention. On these, causative factors included micro-dislodgment (1 patient), and perforation (1 patient). Sudden unexplained exit block occurred late (> 6 weeks) in two patients. In the remainder of patients, pacing thresholds and sensed electrogram amplitudes remained stable throughout the 52-week follow-up period. CONCLUSIONS: The present study validates that smaller surface (i.e., 1.5 mm2) steroid-eluting electrode designs offer excellent pacing and sensing performance with significantly higher pacing impedances. Although questions remain as to the cause of late exit block in two patients in this series, this relatively small surface electrode design offers promise toward achieving greater pacing efficiency and a theoretical 13%-16% (minimum) enhancement in permanent pacemaker longevity.

Administration, Topical↗

PubMed1995

Identification of mRNAs that show modulated expression during colon carcinoma cell differentiation.

To investigate the working hypotheses that stem cells or their early descendants are prime targets for neoplastic transformation, and that the degree to which a neoplasm retains the immature phenotype is an important determinant of tumor aggressiveness, we have identified several mRNAs that are downregulated during the in vitro differentiation of HT29-D4 colon carcinoma cells. These genes include heat-shock cognate protein Hsc70, adenylosuccinate lyase, B23/nucleophosmin, alpha-tubulin, and a novel gene designated DS-1. The DS-1 mRNA has a length of approximately 0.9 kb and is downregulated 4.7-fold upon differentiation. From the DS-1 cDNA, a protein of 206 amino acids with a molecular mass of 24 kDa and an isoelectric point of 10.9 can be deduced. An antiserum directed against a synthetic peptide detected a minor band of the expected size in Western blots, as well as a major band of lower size that may represent a processed form of the protein.

Adenylosuccinate Lyase↗

PubMed1993

Initial experience with single lead VDD system. Case study.

A single pass lead with dual chamber electrode system, designed for atrial and ventricular sensing and ventricular pacing (VDD), was implanted in a 63-year-old man with a history of syncope and second degree atrioventricular (AV) block. Intact VDD pacing function was confirmed at rest and during treadmill exercise. There were no postoperative complications. A single pass lead system that allows VDD mode pacing in patients with symptomatic AV block and competent sinus node function offers several advantages over traditional two lead dual chamber systems. These advantages include enhanced atrial sensing due to a differentially processed signal reliable for P wave detection and effective for rejection of far field ventricular signals, lowered cost and reduced implant time.

Cardiac Pacing, Artificial↗

PubMed1985

Antibiotic treatment and relapse in Whipple's disease. Long-term follow-up of 88 patients.

Reports of clinical relapse occurring after apparently successful antibiotic treatment of Whipple's disease prompted this review of long-term follow-up of treated patients. Follow-up of at least 1 yr after completion of treatment or 2 yr after diagnosis was obtained on 88 patients with documented Whipple's disease by a review of the medical literature, correspondence with the authors as needed, and questionnaires mailed to academic gastroenterology programs in the United States. Relapse was defined on the basis of morphology (preferably) or clinically, or both. Thirty-one patients relapsed, 6 of whom relapsed twice. Fifty-seven patients did not relapse. The mean time to relapse was 4.2 yr. The mean follow-up period of patients who did not relapse was 8.2 yr. The type and number of relapses were as follows: clinical, 16; central nervous system, 13; arthralgia, 5; gastrointestinal, 1; and cardiac, 2. The clinical, arthralgia, and gastrointestinal relapses were evenly distributed between early relapses (occurring less than 2 yr after diagnosis) and late relapses (occurring greater than 2 yr after diagnosis). All cardiac and central nervous system relapses were late. Twenty-one of 49 patients treated with tetracycline alone relapsed. Two relapses were reported in 15 patients treated with penicillin and streptomycin followed by tetracycline. Three relapses developed in 8 patients treated with penicillin alone. Five of the 16 patients treated with other regimens relapsed. Nine of the 13 patients with central nervous system relapse had been initially treated with tetracycline, 2 were treated with penicillin, and 2 were treated with combinations of antibiotics. Results of treatment of central nervous system relapse were poor in 10 of the 11 patients for whom details were available. Results of treatment of non-central-nervous-system relapse were excellent in 19 of 20 patients. It is concluded that tetracycline alone, or penicillin alone, is not adequate initial therapy for Whipple's disease and that central nervous system relapse is resistant to antibiotic therapy. The authors recommend parenteral penicillin and streptomycin followed by 1 yr of oral trimethoprim-sulfamethoxazole therapy or oral trimethoprim-sulfamethoxazole alone for 1 yr as initial therapy for Whipple's disease. Relapse should be defined by demonstration of recurrence of bacilli whenever possible.

Adult↗