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Biomedical subjects

R A Goldstein

Publications and source records attributed to R A Goldstein.

At least 91 records · Page 5Linked to original sources
PubMed1985

Kinetics of rubidium-82 after coronary occlusion and reperfusion. Assessment of patency and viability in open-chested dogs.

Currently available noninvasive techniques are unable to rapidly assess artery patency and tissue viability during acute myocardial infarction. In prior studies, rubidium-82 (Rb-82), a short-lived positron emitter obtained from a generator, was validated as an indicator of flow with a model that included the rate constants for transfer into and out of the cell. Accordingly, in the current study, 20 open-chested dogs with experimental infarction were studied serially at base line, after coronary occlusion, and at reperfusion. Time-activity curves acquired with beta probes on the epicardial surface were used to measure flow and net transfer of rubidium. Flow decreased to 0.41 +/- 0.08 ml/min per gram during occlusion and increased to 2.73 +/- 0.56 ml/min per gram in potentially viable ischemic tissue, whereas flows were 0.32 +/- 0.08 during occlusion (P less than 0.05 vs. viable) and 1.58 ml/min per gram (P less than 0.002 vs. viable) in irreversibly injured tissue. The transfer rate constant for Rb-82, kT, at base line was +1.22 +/- 0.60 X 10(-3) s-1 and did not change significantly during occlusion in viable vs. nonviable samples (+1.41 +/- 1.27 vs. +0.93 +/- 1.51 X 10(-3) s-1, respectively), except that 4 out of 11 nonviable tissue samples had negative kTs. At reperfusion, viable myocardial samples were all positive (+1.26 +/- 1.58 X 10(-3) s-1), whereas all irreversibly injured tissues had a negative kT, indicating leakage of tracer (-1.50 +/- 1.10 X 10(-3) s-1, P less than 0.001). This study suggests that Rb-82 time-activity curves can be useful to determine patency of an infarct related artery and potential viability after reperfusion during myocardial infarction.

Animals↗
PubMed1984

Congestive heart failure with normal systolic function.

Although there have been isolated reports of congestive heart failure (CHF) with normal systolic function, the prevalence and characteristics of this condition have not previously been described. Accordingly, 188 patients with CHF undergoing radionuclide ventriculography were prospectively evaluated. Sixty-seven (36%) had a normal ejection fraction (EF) of 0.45 or greater, and 121, an abnormal EF of less than 0.45. Of these, 72 (55 with an abnormal EF [group I] and 17 with a normal EF [group II]) were also reviewed for clinical characteristics. There was no demographic difference between groups, except that systemic hypertension appeared to be a contributing factor in 65% of the patients in group II, compared with 23% of the patients in group I (p less than 0.002). Echocardiographic left atrial emptying index, reflecting left ventricular compliance, was determined in 72 patients and 14 normal subjects. Left atrial emptying index in normal control subjects was 0.93 +/- 0.11 (+/- standard deviation), compared with 0.41 +/- 0.18 in group I and 0.44 +/- 0.19 in group II patients (p less than 0.001 vs control in both groups). Thus, normal systolic function is common among patients with CHF. Diastolic dysfunction, consistent with a noncompliant left ventricle, was found in both CHF groups.

Echocardiography↗
PubMed1984

Amrinone: acute electrophysiologic and hemodynamic effects in patients with congestive heart failure.

Amrinone is an effective inotropic agent, but its electrophysiologic effects in humans have not been previously determined. Fifteen patients with congestive heart failure (CHF) New York Heart Association functional class II to IV, underwent an electrophysiologic study after withdrawal of all other cardioactive drugs before and after 10 to 20 micrograms/kg/min of intravenous amrinone (doses that increased cardiac index and decreased pulmonary capillary wedge pressure and systemic vascular resistance, p less than 0.002). Amrinone caused no change in PR, QRS, QTc, AH or HV intervals or maximal corrected sinus node recovery time and had no significant effect on the ventricular effective refractory periods. Amrinone decreased the atrial effective refractory period from 256 +/- 40 to 240 +/- 38 ms (p = 0.015), and the atrioventricular (AV) nodal functional refractory period from 374 +/- 65 to 356 +/- 64 ms (p less than 0.05), and enhanced maximal 1:1 AV nodal conduction from 371 +/- 46 to 334 +/- 47 ms (p = 0.006). Nine patients had baseline HV prolongation; this was not affected by amrinone. The frequency of inducible ventricular tachycardia was not significantly affected by amrinone. Holter recordings (24 to 48 hours) were obtained from 10 patients before and after acute oral amrinone dosing (75 to 150 mg every 8 hours). There was no change in the number of ventricular premature contractions per 24 hours (2,197 +/- 3,305 vs 2,616 +/- 2,436) or number of runs of ventricular tachycardia per 24 hours (10 +/- 12 vs 12 +/- 13); however, the number of ventricular couplets per 24 hours increased from 22 +/- 34 to 52 +/- 55 (p = 0.054).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Pharmacologic therapy of low output syndromes after cardiac surgery.

With the advancement of surgical techniques and myocardial protection we can expect that patients previously felt to be inoperable because of poor ventricular function will be surgical candidates. This group of patients will on occasion develop severe left ventricular dysfunction in the peri-operative period. Optimum management in this setting will require acquisition of haemodynamic data, assessment of ventricular loading conditions and inotropic state and the selection of appropriate drug therapy. Drugs are available with specific haemodynamic profiles and therapy is enhanced by matching the abnormal haemodynamics of patients with an appropriate therapeutic agent. If the patient fails to respond quickly to pharmacotherapy, consideration should be directed toward use of an intra-aortic balloon pump.

Adrenergic alpha-Antagonists↗
PubMed1984

Immunopathogenesis, immunology and assessment of activity of sarcoidosis.

To this point we have attempted to summarize what we believe to be the most exciting new findings relative to sarcoidosis, along with providing data in support of those comments. We wish to conclude this brief review by sharing some anecdotal thoughts (no benefit of controlled clinical trials) concerning how the individual practitioner may apply this "research" information in caring for patients. In newly diagnosed patients with sarcoidosis, especially with widespread use of transbronchial lung biopsy, we would recommend BAL at that time because it can provide very valuable information with minimal increased morbidity or cost. BAL, in combination with SACE and possibly gallium scan (not required in all), along with the usual measures such as pulmonary function studies, chest roentgenograms (all of which are already commonly done) permit the clinician to make an accurate conclusion about disease activity in the lungs. Because there are no published therapeutic trials of corticosteroids in which the ultimate prognosis of pulmonary sarcoidosis has been improved, the decision to initiate therapy in these patients remains a clinical one and is commonly based upon practitioner experience rather than a particular laboratory test per se. Once that decision has been made, a decision to repeat any "research" studies would have to be individualized. Clearly serial SACE measures are relatively inexpensive and without morbidity. Moreover, despite their lack of "diagnostic value" serial measurements in known sarcoidosis have been shown to be very valuable in assessing disease activity and may therefore provide the clinician with a valuable aid to monitoring steroid treatment. A less common and much more perplexing circumstance occurs when evaluating patients with sarcoidosis established for several years present with evidence of progressive or chronic pulmonary involvement and dyspnea. In such individuals a measure of activity would be very helpful because the clinician would like to avoid steroids in persons with end stage and irreversible fibrosis and consider their use in those individuals in whom there is evidence of continued disease activity. In this instance, gallium scan, SACE and even BAL may all prove valuable. When we have found SACE elevated and gallium scan positive, we have assumed the disease to be active (even if the chest X-rays show stability).(ABSTRACT TRUNCATED AT 400 WORDS)

Antibody Formation↗
PubMed1983

Myocardial perfusion with rubidium-82. I. Measurement of extraction fraction and flow with external detectors.

Accurate measurement of the regional extraction of a diffusible radiopharmaceutical is essential for the quantifying of regional blood flow, and may also provide an important physiologic or diagnostic indicator of the cellular viability of an organ in man through external detection by positron emission tomography. However, extraction fraction of a diffusible tracer usually decreases as flow increases, and thus noninvasive methods for measuring flow are nonlinear unless the extraction fraction can be measured independently. This report describes the theoretical basis and documents the applicability of this theory for determining, with external detectors, the first-pass regional extraction fraction of rubidium-82 by the heart, following a single intravenous bolus injection of the tracer. Measurement of extraction fraction was found to be independent of flow, thereby making it possible to determine accurately with a single intravenous bolus injection of rubidium-82, the regional blood flow in the myocardium at up to five times normal resting flow.

Coronary Circulation↗
PubMed1983

Myocardial perfusion with rubidium-82. II. Effects of metabolic and pharmacologic interventions.

In order to validate a new method for quantifying coronary blood flow, we injected intravenously a bolus of rubidium-82 (Rb-82) into 28 open-chested dogs under a wide range of flow and physiologic conditions, using beta probes to monitor myocardial radioactivity. Extraction fraction and perfusion were measured using a functional model that separates the data into the free and trapped myocardial rubidium. Extraction and uptake of rubidium were lower during acidosis than during alkalosis and were unchanged by glucose-insulin, digoxin, or propranolol. Myocardial flow, as indicated by rubidium, correlated linearly with simultaneous measurements of flow by microspheres in the same sample volume over a wide range of flow (r = 0.97, n = 106, range 0.02-7.76 ml/min/g). Regional myocardial blood flow can be accurately determined using generator-produced Rb-82. Studies using current state-of-the-art, fast positron-emission tomographic cameras are required to determine the utility of this approach in man.

Animals↗
PubMed1982

Transfer factor.

A workshop on transfer factor, sponsored by the Immunology, Allergic and Immunologic Diseases Program of the National Institute of Allergy and Infectious Diseases, National Institutes of Health, was held in Bethesda, Maryland, on February 25, 1981. The purpose of the meeting was two-fold: (1) to review the state of the art of transfer factor and (2) to suggest future directions for research in this area, specifically in regard to the prophylactic use of transfer factor for varicella-zoster in leukemic children.

Child↗