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Biomedical subjects

J L Anderson

Publications and source records attributed to J L Anderson.

At least 199 records · Page 11Linked to original sources
PubMed1990

Summary of U.S. clinical trials program for evaluation of anistreplase.

Because the reestablishment of coronary blood flow is believed to be central to the benefit of thrombolytic therapy, the U.S. evaluation program of anistreplase has focused on reperfusion, patency, and reocclusion comparisons with approved thrombolytic regimens, including (1) intracoronary streptokinase (completed) (TEAM-I), (2) intravenous streptokinase (completed) (TEAM-II), and (3) intravenous tissue plasminogen activator complex or alteplase (tPA, ongoing) (TEAM-III). The TEAM trials have established that anistreplase possesses similar reperfusion efficacy to intracoronary streptokinase, if given within 4 h, but is much easier to administer; comparisons with currently approved intravenous agents, streptokinase, and tissue plasminogen activator (tPA) have been completed and are being analyzed or are underway; reocclusion and reinfarction rates are low; safety is good, and similar to that of streptokinase; and mortality rates have been low with treatment, consistent with beneficial reports from randomized trials. Based on overall efficacy, ease of administration, and safety, anistreplase has been shown to be a promising agent for treatment of acute myocardial infarction.

Acute Disease↗
PubMed1990

Reassessment of benefit-risk ratio and treatment algorithms for antiarrhythmic drug therapy after the cardiac arrhythmia suppression trial.

The Cardiac Arrhythmia Suppression Trial (CAST) has led to serious reconsideration of both the benefit-risk ratio of antiarrhythmic drug therapy and the appropriate therapeutic approach to various cardiac arrhythmias. Class IC drugs, such as encainide and flecainide, should not be used to treat asymptomatic postinfarction arrhythmias. Furthermore, because the CAST raises serious questions about the concept of treating asymptomatic but "potentially malignant" (prognostically important) arrhythmias guided by ambulatory monitoring, the prophylactic use of any of the antiarrhythmic agents (except beta blockers) must be considered inappropriate and potentially harmful until otherwise established by specific clinical trials. For prophylaxis of malignant ventricular arrhythmias (sustained ventricular tachycardia or ventricular fibrillation), treatment may still begin with standard agents in classes IA, IB, or both, preferably guided by electrophysiologic testing alone or in combination with noninvasive testing. Class IC therapy may be most useful in those patients in this group who do not have such high-risk characteristics for proarrhythmia as a history of multiple myocardial infarctions (MIs), congestive heart failure, or low ejection fraction. Amiodarone is moderately effective for treating these arrhythmias but is reserved as second- or third-line therapy because of its potential organ toxicity. Sotalol, a beta blocker with class III activity, is often effective and relatively well tolerated in these patients and may become a preferred drug when approved. For symptomatic but nonmalignant ventricular arrhythmias, a more conservative approach is more appropriate than in the past, with therapy reversed for those with debilitating symptoms. An initial trial of beta blockade is often appropriate before class I agents are considered.(ABSTRACT TRUNCATED AT 250 WORDS)

Algorithms↗
PubMed1990

Time delays in the diagnosis and treatment of acute myocardial infarction: a tale of eight cities. Report from the Pre-hospital Study Group and the Cincinnati Heart Project.

To establish the magnitude of prehospital and hospital delays in initiating thrombolytic therapy for acute myocardial infarction, the time from telephone 911 emergency medical system (EMS) activation to treatment and its components were analyzed from eight separate ongoing trials. This included estimates of ambulance response time, prehospital evaluation and treatment time, and time from admission to the hospital to initiation of thrombolytic therapy. The average time from EMS activation to patient arrival at the hospital was prospectively determined to be 46.1 +/- 8.2 minutes in 3715 patients from eight centers. The time from admission to the hospital to initiation of thrombolytic therapy was retrospectively determined to be 83.8 +/- 55.0 minutes in a separate group of 730 patients from six centers. Both the prehospital and hospital time delays were much longer than those perceived by paramedics and emergency department directors. Shorter hospital time delays were observed in patients in whom a prehospital ECG was obtained as part of a protocol-driven prehospital diagnostic strategy and a diagnosis of acute infarction made before arrival at the hospital (36.3 +/- 11.3 minutes in 13 patients). These results show that the magnitude of time required to evaluate, transport, and initiate thrombolytic therapy will preclude initiation of treatment to most patients within the first hour of symptoms. Implementation of a protocol-driven prehospital diagnostic strategy may be associated with a reduction in time to thrombolytic therapy.

Electrocardiography↗
PubMed1990

Long-term beta-blocker vasodilator therapy improves cardiac function in idiopathic dilated cardiomyopathy: a double-blind, randomized study of bucindolol versus placebo.

PURPOSE: Bucindolol is a potent nonselective beta-blocking agent with vasodilatory properties. In this study, we evaluated the effects of long-term bucindolol therapy in the treatment of heart failure from idiopathic dilated cardiomyopathy. PATIENTS AND METHODS: Patients were eligible for enrollment if they had symptomatic heart failure, idiopathic dilated cardiomyopathy, and left ventricular ejection fraction less than 0.40. All patients received an initial test dose of 12.5 mg bucindolol orally every 12 hours for two or three doses. Patients tolerating the test dose were randomly assigned (double-blind) to receive bucindolol or placebo in a 3:2 ratio. Study medication was begun at a dose of 12.5 mg orally every 12 hours and gradually increased over a 1-month period until either a maximum tolerated dose or a target dose of 100 mg every 12 hours was reached. Study medication was then continued for an additional 2 months. RESULTS: A total of 24 patients were enrolled into the study. Twenty-three patients tolerated bucindolol test challenge; 14 were randomized to receive bucindolol, and nine were randomly assigned to receive placebo. The placebo group (age 56 +/- 2 years) was significantly older than the bucindolol group (46 +/- 3 years), but by all other clinical and hemodynamic parameters the two groups were comparable. Twenty-two of 23 patients completed the study. Patients treated with bucindolol had significant improvements in clinical heart failure symptoms and in resting hemodynamic function, including an increase of left ventricular ejection fraction (0.26 +/- 0.02 to 0.35 +/- 0.09, p = 0.003), cardiac index (2.2 +/- 0.1 to 2.5 +/- 0.4 L/minute/m2, p = 0.014), and left ventricular stroke work index (25 +/- 3 to 35 +/- 7 g.m/m2, p = 0.002) and a decrease in pulmonary artery wedge pressure (17 +/- 3 to 10 +/- 5 mm Hg, p = 0.005) and heart rate (86 +/- 3 to 75 +/- 9 beats/minute, p = 0.012). Patients treated with bucindolol also had a significant increase in exercise left ventricular ejection fraction (0.26 +/- 0.03 to 0.32 +/- 0.14, p = 0.015) and reduction in questionnaire-measured symptoms (p = 0.007) and New York Heart Association functional class (p less than 0.001). However, total treadmill exercise duration and maximal oxygen consumption with exercise did not change. No changes in rest or exercise parameters were observed in the placebo-treated group. Central venous plasma norepinephrine concentration decreased significantly in the bucindolol-treated group (423 +/- 79 to 212 +/- 101 pg/mL, p = 0.010), but was unchanged in the placebo-treated group. CONCLUSION: Bucindolol is well tolerated in patients with idiopathic dilated cardiomyopathy and congestive heart failure, and therapy for 3 months is associated with improved resting cardiac function, improved heart failure symptoms, and a reduction in venous norepinephrine concentration.

Adrenergic beta-Antagonists↗
PubMed1990

Facilitating changes in supervisees' clinical behaviors: an experimental investigation of supervisory effectiveness.

This research was conducted to determine whether supervisees altered their clinical behaviors as a consequence of a joint data-analysis method of clinical supervision. Four beginning graduate student clinicians assigned to articulation clients were supervised in accordance with tenets of Cogan's Clinical Supervision Model and Anderson's Continuum of Supervision. Supervision focused on the targeted dependent variables of clinician "explanations," "informative feedback," and "directive responses to off-task utterances." Visual inspection of multiple baseline data indicated that target behaviors improved after they became the focus of supervision. The supervisory procedures implemented in this study effected positive changes in the supervisees' clinical behaviors. Qualitative discoveries that relate to the practicalities of daily supervision are discussed.

Clinical Competence↗
PubMed1990

Correlation between class II antigen (DR) expression and interleukin-2-induced lymphocyte proliferation during acute cardiac allograft rejection.

We have previously reported a correlation between biopsy-proven rejection and the presence of IL-2-responsive lymphocytes for biopsy specimens from human cardiac allografts. We thus hypothesized a relationship between tissue expression of HLA class II antigen (DR) and the outgrowth of IL-2-responsive lymphocytes. Employing immunofluorescence DR staining with a propidium iodide counterstain in consecutive specimens from 41 patients, we found two patterns of DR expression: DR expressed on the vascular endothelial surface (donor antigens) and/or on myocardial infiltrating cells (presumably recipient antigens). Specimens were categorized by histologic diagnosis as "baseline nonrejecting controls" that were obtained 7.5 +/- 0.4 (mean +/- SE) days posttransplantation, "nonrejecting" (obtained 59.9 +/- 5.8 days posttransplantation), "prerejecting" (obtained 47.7 +/- 6.3 days posttransplantation), and "rejecting" (obtained 101.3 +/- 10.1 days posttransplantation). Prerejecting specimens were histologically negative specimens obtained from patients a mean of 6.0 +/- 0.4 days before a biopsy-proven rejection episode. The percentage of specimens positive for interstitial DR staining were: less than 1% for controls, 30% for nonrejecting specimens, 68% for prerejecting, and 46% for rejecting. For vascular DR staining, 25% of control specimens were positive, 56% of nonrejecting, 74% of prerejecting, and 73% of rejecting specimens. Culture positivity was seen for 38% of controls, 35% of nonrejecting specimens, 79% of prerejecting, and 70% of rejecting. Vascular DR staining was higher than interstitial staining for all specimen categories. For the vascular pattern, the mean score was significantly higher for culture-positive specimens compared to culture negative (0.87 +/- 0.1 vs. 0.59 +/- 0.1; P less than 0.01). A similar relationship was not found for the interstitial pattern. Lymphocyte growth occurred in conjunction with vascular DR upregulation significantly more frequently than in conjunction with interstitial DR expression (65% vs. 35% of culture-positive specimens, P less than 0.0001). These findings suggest a relationship between DR expression, lymphocyte growth, and acute rejection. Vascular DR and interstitial DR patterns show several differences with respect to kinetics of expression and correlation with histology and culture, and thus may represent different processes.

Blood Vessels↗
PubMed1990

Spontaneous variability in ventricular ectopic activity during chronic antiarrhythmic therapy.

Previous determinations of variability in frequency of ventricular arrhythmias have been based on repeated recordings obtained in the absence of therapy. We evaluate variability during "effective" treatment with antiarrhythmic drugs. Variability in the percent suppression of premature ventricular complexes (PVCs) was determined in 55 patients with chronic arrhythmias who underwent multiple ambulatory electrocardiographic recordings during evaluation of chronic therapy with antiarrhythmic drugs initially determined to be effective, which was defined as 70% or more reduction in total PVC frequency or 90% or more reduction in repetitive forms. During chronic therapy, total PVCs were suppressed by 92%, averaged after a logarithmic transformation step, and repetitive beats were suppressed by 88%. Variability in suppression was substantial. The one-sided 95% confidence intervals required a fall in suppression of total PVCs to 40% or less to exceed limits of spontaneous variability and of repetitive PVCs to 66% or less. Suppression declined at least once during therapy to less than 60% for total PVCs in 24 of 55 patients (44%) and to less than 80% for repetitive PVCs in 13 of 33 patients (39%); nine patients (16%) showed increases in PVC frequency at least once to levels above pretreatment baseline. Seven subgroups were analyzed for their effects on variability and loss of suppression: age, gender, disease etiology, cardiac function, baseline PVC frequency, use of beta-blockers, and class of antiarrhythmic drug. Differences in confidence bounds and loss of suppression were found to be determined in a complex way by subgroup differences in variability and in initial levels of PVC suppression. Variability was greater for patient subgroups with greater PVC frequency, beta-blocker therapy, and non-coronary artery disease. However, clinical loss of suppression was more common only in more elderly patients and those with worse cardiac function. In summary, substantial variability in arrhythmia frequency occurs during effective antiarrhythmic therapy, and the 95% confidence limits of spontaneous variability are broad and determined in a complex way. Careful consideration should be given before concluding on the basis of a single Holter test that changes (increases) in arrhythmia frequency, especially in certain subgroups, are caused by treatment failure.

Adrenergic beta-Antagonists↗
PubMed1990

Therapeutic management of acute myocardial infarction.

Criteria for selecting patients for thrombolytic therapy are presented, the major benefits of the currently approved thrombolytic agents are reviewed, and management considerations, including contraindications and the role of ancillary therapy, are discussed. Coronary thrombosis is now believed to play a central role in the pathogenesis of acute myocardial infarction (AMI). Re-establishment of coronary perfusion by thrombolysis has been extensively studied in the past decade and is now regarded as established therapy for patients with ischemic pain of brief (less than six hours') duration who have electrocardiographic ST-segment elevation, are less than 75 years of age, and have no contraindications. Studies supporting thrombolytic therapy have focused on the endpoints of (1) coronary artery patency or reperfusion, (2) improvement in left ventricular function, and (3) reduction in mortality. Benefits for each of these three endpoints have been established and are reviewed with respect to streptokinase, alteplase, and anistreplase, the three agents that have been approved for intravenous use in patients with AMI. The risk of bleeding, including intracranial hemorrhage, remains a concern for all patients. Ancillary therapies to be considered include aspirin, heparin, nitroglycerin, and beta blockers. Recent studies testing different strategies for coronary angiography and angioplasty plus surgery have generally supported a conservative approach, with interventions performed for clinical reasons rather than prophylaxis. Although the currently approved agents have differing pharmacologic profiles, none has yet proved to be clearly superior in the management of patients with AMI. Nonetheless, these agents remain the most promising means of treating selected patients.

Acute Disease↗
PubMed1990

Rod visual fields in cone-rod degeneration. Comparisons to retinitis pigmentosa.

Dark-adapted visual fields to short- and long-wavelength stimuli were obtained from 20 patients with cone-rod degeneration, 20 patients with retinitis pigmentosa, and ten normal subjects. Patients were selected because they retained rod electroretinographic (ERG) function over a sufficient range for the Naka-Rushton analysis of retinal illuminance versus amplitude functions. Patients with cone-rod degeneration retained a relatively normal field topography although overall sensitivity was reduced. The mean sensitivity loss was consistent with a small elevation in ERG semisaturation constant and minimally delayed rod b-wave implicit times. Rod visual fields from patients with retinitis pigmentosa retaining rod ERG function were consistent with log sensitivity profiles reported previously for type 2 patients. Sensitivity loss was greatest in midperipheral regions, with most patients showing least loss in the far periphery. Disproportionate loss in the midperiphery is consistent with a large elevation in the ERG semisaturation constant and prolonged rod b-wave implicit times.

Adolescent↗
PubMed1989

Reperfusion, patency and reocclusion with anistreplase (APSAC) in acute myocardial infarction.

Because the reestablishment of coronary blood flow is believed to be central to the benefit of thrombolytic therapy, measurements of reperfusion (i.e., angiography before and after therapy), patency (i.e., angiography after therapy) and reocclusion rates are important to the evaluation of new thrombolytic therapies. For anisoylated plasminogen streptokinase activator complex (APSAC, anistreplase), comparisons have been made with control or placebo therapies to assess absolute efficacy, and with streptokinase to assess relative efficacy. In pooled experience from reperfusion studies, APSAC (30 U over 2 to 5 minutes) led to angiographic reperfusion in 55% of patients (98 of 177) who had symptoms of acute myocardial infarction (MI) for less than 6 hours. Among 107 patients treated with APSAC in angiographic patency studies, 69% (74) showed an open infarct-related artery 1 to 4 hours after therapy. (Patency rates are generally 10 to 20% greater than reperfusion rates, because some patients with acute MI may have a patent [subtotally occluded or spontaneously reperfused] infarct-related artery when entered into patency studies.) Using early peaking (less than or equal to 15 hours) of the creatine kinase curve as an indicator, a patency rate of 63% was observed among 387 patients treated with APSAC. The initial success rate with thrombolytic therapies is diminished by the rates of reocclusion and reinfarction, which must be accounted for in determining the net success of therapy. In 6 studies, a total of 87 patients with initially patent arteries after APSAC returned for reevaluation in 1 to 3 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Anistreplase↗
PubMed1989

Relation of plasma D-dimer concentrations to coronary artery reperfusion before and after thrombolytic treatment in patients with acute myocardial infarction.

This study was designed to investigate the possible role of pre- and posttreatment plasma D-dimer concentration as a reflection of coronary artery thrombolysis. Blood was collected from 206 patients with angiographically documented acute coronary occlusion presenting within 6 hours of symptom onset who were enrolled in a prospective study comparing intravenous APSAC (30 U) (IV-APSAC) with intracoronary streptokinase (160,000 U) (IC-SK). D-dimer concentrations in 104 patients after IV-APSAC therapy were higher than in 90 patients after IC-SK (mean +/- standard error, 1,009 +/- 60 vs 603 +/- 45, p less than 0.001), but there was no difference in patients with and without reperfusion (1,096 +/- 88 vs 875 +/- 67, p = 0.1 for IV-APSAC, and 587 +/- 48 vs 634 +/- 95, p = 0.6 for IC-SK). The median concentrations before treatment were similar in the IV-APSAC and IC-SK groups (93 and 90 ng/ml, respectively). These were higher than the value in 25 ambulatory control subjects (72 ng/ml) but lower than in 29 post-AMI (6 to 30 hours) patients and in preoperative orthopedic patients (140 ng/ml each). There was no difference in D-dimer concentrations in patients with grade 0 or grade 1 coronary artery occlusion (median 85 vs 90 ng/ml) or in patients with or without ultimate successful reperfusion (median 85 vs 93 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Relative efficiency and risk of endomyocardial biopsy: comparisons in heart transplant and nontransplant patients.

Right ventricular endomyocardial biopsy remains the gold standard for the diagnosis of acute rejection of the cardiac allograft. Among 704 consecutive procedures performed in 39 transplant recipients (2,842 myocardial samples), endomyocardial biopsy by either the right internal jugular (n = 661) or the femoral venous (n = 43) approach was compared with 243 consecutive procedures performed in nontransplant patients (n = 149 and n = 94, internal jugular and femoral approach, respectively). The internal jugular vein could not be located in only 0.61% (4/661) of heart transplant versus 5% (7/149) of nontransplant procedures (P less than 0.001). Vascular access plus sufficient myocardial sampling was obtained in all but 0.61% (4/661) internal jugular procedures performed in heart transplant patients and in all but 7% (11/149) of those performed in nontransplant patients (P less than 0.0001). (Vascular access was achieved in all femoral venous procedures performed in both transplant and nontransplant patients; sampling was successful after vascular access in all heart transplant recipients and all but two [2.1%] nontransplant procedures.) Cardiac complications occurred in nontransplant patients after one internal jugular procedure (cardiac perforation with tamponade) and after one femoral venous procedure (pericardial effusion). No cardiac complications occurred in transplant recipients, but 2 other complications were observed: One local abscess and one superior vena caval perforation with hemothorax associated with hypotension, both after an internal jugular approach. The overall efficiency (no safety problem; vascular access and adequate sample) was higher among transplant than nontransplant procedures (99% vs 93%, respectively, P less than 0.0001). These observations continue to support routine application of endomyocardial biopsy for monitoring rejection in cardiac transplant patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Effect of dietary brussels sprouts with increased selenium content on mammary carcinogenesis in the rat.

Brussels sprouts (Brassica oleracea, L; Jade cross E, hybrid cultivar) were cultivated with inorganic selenium added to the plant growth medium. Sprague-Dawley, female, weanling rats were divided into groups and fed 20% brussels sprouts diets containing either 0.03, 0.58, 1.29, or 6.71 ppm of selenium naturally occurring in the sprouts. These diets were fed 2 weeks before and 2 weeks after a single dose of 7,12-dimethylbenz[a]anthracene (DMBA), and the rats were then placed on a low selenium basal diet for an additional 25 weeks. All brussels sprouts diets reduced the incidence of DMBA-induced mammary carcinogenesis. Increased dietary levels of naturally occurring selenium did not further depress mammary tumorigenesis. The time periods of selenium feeding may have been too brief to observe any additional tumor reductions.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1989

One measure of supervisory effectiveness in speech-language pathology and audiology.

This investigation developed and utilized a methodology for studying the follow-through of student clinicians from supervisory conferences to later activities. Based upon an earlier investigation in which 1,389 commitments made by 64 supervisees were identified and analyzed, completion of each commitment was measured in this investigation to determine if specific behaviors of clinicians occur after making commitments in supervisory conferences. Results indicated that clinicians demonstrate greater completion of commitments when structured accountability (i.e., written agreement) is introduced early into and subsequently faded from supervisory conferences, and that the written agreement is more beneficial for beginning clinicians than for experienced clincians. Of utmost importance was the demonstration that specific behaviors of supervisees can be followed and measured over time, and that certain behaviors of clinicians occur as a direct result of commitments made during conferences with a supervisor.

Audiology↗
PubMed1989

Optimal thrombolytic therapy: for whom, when, how.

Here are criteria for patient selection, as well as contraindications for intravenous thrombolysis, the advantages and disadvantages of available drugs, and protocols for administration of each.

Clinical Trials as Topic↗