Cardiac sarcolemma enzymes & liver microsomal cytochrome P450 in isoproterenol treated rats

In the heart sarcolemma and sarcoplasmic reticulum of rat there was significant decrease in cholesterol and phospholipid levels in isoproterenol treated rats. The membrane enzymes lipoprotein lipase and Ca-ATPase decreased due to myocardial necrosis. Lipid peroxide and xanthine oxidase were significantly enhanced, whereas superoxide dismutase was markedly decreased in ischemic heart produced by isoproterenol. Cytochrome P450, b5 and heme were found to be degraded in myocardial cell damage. Guggulsterone showed a marked protective effect on the cardiac enzymes and cyt P450 system against myocardial necrosis induced by isoproterenol.

[Initial experiences with a monoclonal antibody to the progesterone receptor complex]

Today, the immuncytochemical demonstration of estrogen receptors can be regarded as established. Recently, a monoclonal antibody (mab) against the progesterone receptor-complex became commercially available. The antibody Mi 60-10, developed by Milgrom and co-workers, is murine and principally directed against the progesterone receptor of the rabbit, but it also attacks an "epitop" of the human receptor. The Western-Blot analysis shows the antibody having several specific bands against T-47-D cells in the region of 110,000 dalton. To estimate the practical performance of this antibody, 73 primary breastcarcinomas were incubated with both the ER-ICA-Kit and the new "mab". The PAP method was used for visualisation. In a frozen section the mab Mi 60-10 proved as successful as the ER-ICA-Kit. However, in contrast to the ER-ICA-Kit, the mab Mi 60-10 is also successful in locating the receptor, also in formalin-fixed samples embedded in paraffin. This is also the case with blocks, which were stored for several years. In aspirated cytological samples the immunocytochemical demonstration of progesterone was just as successful as that of estrogen and comparable with results on the histological section. A satisfactory validity can be obtained today through the development of highly specific monoclonal antibodies against the progesterone receptor complex, with the complete receptor diagnosis of mammary carcinoma both immunocytochemically in frozen sections and additionally, of progesterone receptors in paraffin wax sections. The only current problems involve the exact quantification of the immunocytochemical results. It is predictable today, that the DCC-method, when compared to the immunocytochemical receptor analysis, will reduce in significance.

Effect of the degree of effort on the sensitivity of the exercise thallium-201 stress test in symptomatic coronary artery disease

The sensitivity of ST-segment depression on the electrocardiogram during exercise is influenced by the level of effort. Whether such is the case with thallium-201 imaging (initial defect or redistribution) has not been established. Accordingly, the prevalence of these parameters was evaluated in 288 patients (age 59 +/- 10 years, 88% men) with coronary artery disease who underwent both exercise thallium-201 imaging and coronary angiography within 3 months of each other: 159 had a prior myocardial infarction, 72 had 1-vessel, and 216 had multivessel disease. The degree of effort was evaluated by 3 criteria: (1) percentage of maximal predicted heart rate (less than or equal to 65, greater than 65 to 85, greater than 85%); (2) workload during exercise (less than or equal to 4, greater than 4 to 8, greater than 8 METs); and (3) duration of exercise (less than or equal to 3, greater than 3 to 6, greater than 6 minutes). The prevalence of defects on initial images was higher than both redistribution on delayed images and ST-segment depression on the electrocardiogram (p less than 0.01). The overall prevalence of initial defects remained the same for all levels of effort and was not influenced by the presence or absence of a prior infarction. However, it decreased in patients with 1-vessel disease who exercised to higher workloads. The prevalence of redistribution on delayed thallium-201 images was higher than that of ST-segment depression on the electrocardiogram (p less than 0.01), except at higher levels of effort where they were similar.(ABSTRACT TRUNCATED AT 250 WORDS)

Albunex: a safe and effective commercially produced agent for myocardial contrast echocardiography

Microbubble solutions of sonicated human serum albumin have been shown to be effective echocardiographic contrast agents free from adverse effects on coronary blood flow, left ventricular function, and systemic hemodynamics. Albunex is a commercially prepared solution of air-filled albumin microspheres prepared from sonicated 5% human serum albumin. The effects of Albunex on coronary blood flow, left ventricular function, and systemic hemodynamics, as well as contrast enhancement were evaluated in 10 open chest, anesthetized dogs. After an intracoronary injection, Albunex did not alter left atrial, left ventricular systolic or end-diastolic, or mean aortic pressures. It did not cause a coronary hyperemic response, alter left ventricular systolic thickening, or lower the peak positive left ventricular dp/dt. It did not alter these measurements even in the presence of a critical coronary stenosis. The contrast opacification produced by Albunex microbubbles was dose dependent (optimal dose range of 0.033 to 0.5 ml/kg), with attenuation occurring at higher doses. In conclusion, although Albunex provides adequate contrast enhancement, intracoronary injection of Albunex does not significantly alter coronary blood flow, left ventricular function, or systemic hemodynamics. Because of the standardized size and concentration of the microspheres, Albunex may be an ideal agent for myocardial contrast echocardiography.

Functional significance of predischarge exercise thallium-201 findings following intravenous streptokinase therapy during acute myocardial infarction

The purpose of this study was to determine which predischarge exercise thallium-201 imaging pattern(s) best correlate with myocardial salvage following intravenous streptokinase therapy (IVSK). Myocardial salvage was defined as improvement in regional left ventricular function determined by two-dimensional echocardiography between the time of admission and time of discharge in 21 prospectively studied patients receiving IVSK within 4 hours of chest pain. All patients had coronary angiography 2 hours following IVSK. Whereas 16 of the 21 patients (76%) had patent infarct-related vessels, only seven (33%) showed significant improvement in regional function at hospital discharge. Eleven patients demonstrated persistent defects (PD), and five each showed delayed and reverse redistribution. Patients with both delayed and reverse redistribution demonstrated significant improvement in regional left ventricular function score, while those with PD did not (+3.9 +/- 3.3 versus -0.5 +/- 2.9, p = 0.004). All other clinical, exercise, electrocardiographic, scintigraphic, and angiographic variables were similar between all patients, with the exception of the interval between chest pain and the institution of IVSK, which was longer in patients with reverse compared to delayed redistribution (3.5 +/- 0.4 versus 2.2 +/- 0.4 hours, p = 0.001). It is concluded that both delayed and reverse redistribution seen on predischarge exercise thallium-201 imaging are associated with myocardial salvage, defined as serial improvement in regional systolic function. Despite a high infarct vessel patency rate in patients with acute myocardial infarction receiving IVSK within 4 hours of onset of symptoms, only one third demonstrated improvement in regional function that was associated with either delayed or reverse redistribution seen on predischarge exercise thallium-201 imaging.

Effect of fish oil concentrate on lipoprotein composition in NIDDM

Non-insulin-dependent diabetes mellitus (NIDDM) is associated with elevated very-low-density lipoprotein (VLDL) triglyceride concentrations and abnormalities of low-density lipoprotein (LDL) composition. Because fish oil supplementation may favorably affect lipid and lipoprotein concentrations in nondiabetic subjects, we determined the effect of fish oil concentrate on plasma lipids and lipoprotein composition in patients with NIDDM. Dietary-supplementation 1-mo periods of 4.0 and 7.5 g of omega-3 fatty acids in fish oil were compared with a placebo of 12 g safflower oil by use of a single-blind crossover design. Medications, including antidiabetic therapy, were continued through the study. Compared with safflower oil treatment, fish oil supplementation resulted in a significant reduction of total plasma triglycerides of 24% at the 4-g dose and a larger reduction of 39% at the 7.5-g dose. These decreases were due to similar reductions in VLDL triglycerides. LDL cholesterol levels were mildly elevated, but a larger 20% increase in LDL apolipoprotein B (apoB) concentration was observed. During supplementation with the fish oil concentrate, the LDL cholesterol-to-apoB ratio was significantly reduced when compared with pretreatment values, but not when compared with safflower oil treatment. High-density lipoprotein (HDL) cholesterol and plasma apoA1 levels were not significantly changed during fish oil treatment. At the 7.5-g dose, fasting glucose and glycohemoglobin levels increased by 20 and 12%, respectively, but were unchanged at the lower level of supplementation. Thus, in NIDDM patients, dietary supplementation with omega-3 fatty acids induces a reduction in total plasma and VLDL triglyceride levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Myocardial contrast echocardiography in humans. II. Assessment of coronary blood flow reserve

The hypothesis that myocardial contrast echocardiography could be used to simultaneously assess coronary blood flow reserve and the size of the perfusion bed supplied by a coronary artery was examined in nine patients and six dogs. All patients were undergoing cardiac catheterization and had single vessel coronary artery disease (greater than or equal to 85% stenosis of either the proximal left anterior descending or the left circumflex coronary artery); the six dogs had a critical stenosis of the left circumflex coronary artery. Three milliliters of sonicated Renografin-76 (mean microbubble size 6 micron) was injected into the left main coronary artery before and after intracoronary administration of papavarine, 6 to 9 mg. The beds supplied by the normal and stenotic vessels could not be differentiated during contrast echocardiography before injection of papavarine. However, after papavarine, the normal vascular bed showed significantly more contrast enhancement than did the bed supplied by the stenotic artery. This disparity in contrast enhancement made it possible to delineate the size of the bed perfused by the stenotic vessels. When quantitative analysis of the time-intensity curves obtained from the echocardiograms was performed in the dogs, the absolute values for the area under the curve, peak contrast intensity and curve width did not correlate with absolute blood flows measured with radiolabeled microspheres. However, the ratios of the areas under the curves derived from the two vascular beds before and after papavarine correlated well with the ratios of blood flows between the two beds during the same stages (r2 = 0.73 by linear regression and r2 = 0.85 by an exponential function). In comparison, the ratios of peak amplitudes and curve widths before and after papavarine had poor correlations with ratios of flows from the two beds (r2 = 0.18 and 0.02, respectively). In conclusion, myocardial contrast echocardiography can be used to simultaneously assess coronary blood flow reserve and the size of the perfusion bed supplied by a stenotic vessel.

Myocardial contrast echocardiography without significant hemodynamic effects or reactive hyperemia: a major advantage in the imaging of regional myocardial perfusion

All agents used for myocardial contrast echocardiography to date produce adverse hemodynamic effects and alter coronary blood flow. It was hypothesized that because 5% human albumin, when sonicated for use as a contrast agent, is neither hyperosmolar nor a calcium chelator, it would not have significant effects on coronary blood flow, left ventricular function or systemic hemodynamics. Albumin microbubbles of two distinct sizes (mean size 2.9 and 5.8 micron) were produced and compared with nonsonicated albumin, nonsonicated Renografin, sonicated Renografin and hand-agitated Renografin for their effects on hemodynamics, coronary blood flow and regional left ventricular systolic thickening in 15 open chest anesthetized dogs. None of the albumin solutions significantly altered left atrial, left ventricular systolic and end-diastolic and mean aortic pressures. These agents did not cause a coronary hyperemic response or alter left ventricular systolic thickening, but slightly lowered the peak positive left ventricular maximal rate of rise in pressure (dP/dt) (-4.1 +/- 5.4%, p less than 0.01). In contrast, all the Renografin solutions caused significant changes in all these variables (p less than 0.02). In six dogs. albumin solutions did not alter these variables even in the presence of critical coronary stenosis. The contrast opacification produced by 5.8 micron albumin microbubbles was equivalent to that produced by sonicated Renografin. Compared with an equivalent amount of saline and nonsonicated albumin solutions, 10 ml of sonicated albumin did not produce any evidence of infarction, embolization or hemorrhage in the myocardium, brain or kidneys of rabbits.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of obesity on sulfonamide disposition in Zucker rats

The genetically obese Zucker rat was used as a model of obesity and compared to its lean littermate to assess and quantify obesity-altered changes in the in vivo disposition of six sulfonamides. Body composition determination indicated that the obese rats were twice the weight of lean rats and a distinct trend towards an increase in fat free mass and total body water was observed. The sulfonamide blood concentration was measured by colorimetry after a 7 mg/kg intravenous dose. All sulfonamides exhibited a biexponential decline of blood concentration with time. The volume of distribution and clearance of sulfanilamide in lean and obese rats were similar resulting in similar elimination half-lives. A decrease in clearance coupled with a trend towards an increase in volume of distribution prolonged the elimination half-life of sulfadiazine in obese rats. For sulfapyridine, sulfamerazine, sulfisomidine and sulfisoxazole, increases in the volumes of distribution and clearances resulted in similar elimination half-lives in lean and obese rats. The free fractions of the sulfonamides were significantly increased in the serum of obese rats, the influence of which on the volume of distribution and clearance is discussed.

Increased exercise thallium-201 lung uptake: a noninvasive prognostic index in two-vessel coronary artery disease

To determine the physiologic impact of two-vessel coronary artery disease and its effect on prognosis, a series of clinical, angiographic, exercise and quantitative thallium-201 (Tl-201) imaging parameters were analyzed in 85 consecutive two-vessel coronary artery disease patients followed for 52 +/- 27 months after coronary angiography and Tl-201 scintigraphy. End points were cardiac death (n = 3), myocardial infarction (n = 6) and coronary bypass graft surgery more than three months after testing (n = 16). Using Cox Hazards survival analysis, early cardiac events were not predicted by: myocardial infarction or anginal history; resting left ventricular function; exercise blood pressure response; angina or severity of ECG ST segment depression (mm); Tl-201 defect size; redistribution or clearance; angiographic patterns; or the presence of proximal left anterior descending disease. Significant predictors of adverse cardiac events were: increased exercise lung to heart Tl-201 ratio (0.59 +/- 0.12 versus 0.46 +/- 0.1; P less than 0.0001); ECG lead extent of ST segment depression (P less than 0.03); and exercise heart rate response (P less than 0.047). Event-free survival for patients with normal and abnormally increased lung to heart Tl-201 ratios at 48 months was 76% versus 63% (P less than 0.003). It was concluded that two-vessel coronary artery disease survival correlates with exercise Tl-201 uptake which reflects exercise induced left ventricular dysfunction.

Success of internal mammary bypass grafting can be assessed intraoperatively using myocardial contrast echocardiography

To determine whether the success of internal mammary artery bypass grafting can be assessed intraoperatively using myocardial contrast echocardiography, sonicated Renografin-76 was injected into the aortic root of 11 dogs during the delivery of cardioplegic solution. Studies were performed with the left anterior descending coronary artery patent and totally occluded, and after internal mammary artery bypass grafting distal to the occluded vessel. Flow rate during cardioplegia was constant for all three stages in each experiment. Myocardial contrast echocardiography clearly demonstrated homogeneous myocardial perfusion with the left anterior descending coronary artery patent, lack of perfusion in the left anterior descending artery bed during its occlusion and excellent perfusion of the occluded bed after internal mammary artery bypass grafting distal to the occlusion in 10 of the 11 dogs. In one dog, the bypass graft was technically inadequate and contrast opacification was not noted in the left anterior descending artery bed after internal mammary artery bypass grafting. The exponential function C(t) = Ae-alpha t + Be-beta t was fitted to computer-derived time-intensity curves from the myocardium, where alpha denotes contrast washout and beta denotes contrast appearance. Respective values for alpha and beta (mean + 1 SD) were similar for the patent left anterior descending coronary artery and after internal mammary artery bypass grafting distal to the occluded artery (0.11 +/- 0.10 versus 0.10 +/- 0.10, and 2.5 +/- 2.4 versus 1.1 +/- 0.56). In conclusion, myocardial contrast echocardiography has potential for intraoperative assessment of the adequacy of coronary artery bypass grafting.

Superiority of quantitative exercise thallium-201 variables in determining long-term prognosis in ambulatory patients with chest pain: a comparison with cardiac catheterization

The purpose of this study was to determine the prognostic utility of quantitative exercise thallium-201 imaging and compare it with that of cardiac catheterization in ambulatory patients. Accordingly, long-term (4 to 9 years) follow-up was obtained in 293 patients who underwent both tests for the evaluation of chest pain: 89 had undergone coronary artery bypass graft surgery within 3 months of testing and were excluded from analysis, 119 experienced no cardiac events and 91 had an event (death in 20, nonfatal myocardial infarction in 21 and coronary artery bypass operations performed greater than 3 months after cardiac catheterization in 50). When all variables were analyzed using Cox regression analysis, the quantitatively assessed lung/heart ratio of thallium-201 activity was the most important predictor of a future cardiac event (chi 2 = 40.21). Other significant predictors were the number of diseased vessels (chi 2 = 17.11), patient gender (chi 2 = 9.43) and change in heart rate from rest to exercise (chi 2 = 4.19). Whereas the number of diseased vessels was an important independent predictor of cardiac events, it did not add significantly to the overall ability of the exercise thallium-201 test to predict events. Furthermore, information obtained from thallium-201 imaging alone was marginally superior to that obtained from cardiac catheterization alone (p = 0.04) and significantly superior to that obtained from exercise testing alone (p = 0.02) in determining the occurrence of events. In addition, unlike the exercise thallium-201 test, which could predict the occurrence of all categories of events, catheterization data were not able to predict the occurrence of nonfatal myocardial infarction. The exclusion of bypass surgery and previous myocardial infarction did not alter the results. In conclusion, data from this study demonstrate that exercise thallium-201 imaging may be superior to data from both exercise testing alone and cardiac catheterization data alone for predicting future events in ambulatory patients who have undergone both exercise thallium-201 imaging and catheterization for the evaluation of chest pain.

Identification of the human papillomavirus type 18 E6 and E6 proteins in nuclear protein fractions from human cervical carcinoma cells grown in the nude mouse or in vitro

We recently reported the transcription patterns of human papillomavirus (HPV) type 18 sequences in human cervical carcinoma cell lines. The open reading frames (ORFs) E6* and E6 represent the 5'-terminal cistrons in HPV18 mRNAs. ORF E6* was assumed to be specific for HPV types associated with genital carcinomas. To identify the predicted gene product, ORF E6* from a HeLa cDNA clone was expressed as an MS2 fusion protein in Escherichia coli. The C-terminal 23 amino acid residues were chemically synthesized. A panel of monoclonal antibodies was generated, recognizing E6* and E6* plus E6, respectively. In human cervical carcinoma cell lines grown in vitro these monoclonal antibodies specifically immunoprecipitate the putative Mr 17,000 and 18,000 HPV18 E6 proteins in nuclear protein fractions. In a HPV18 DNA containing human cervical carcinoma established in nude mice, these monoclonal antibodies specifically immunoprecipitate a polypeptide with a molecular weight of 6500 as predicted for the HPV18 ORF E6* gene product in a nuclear protein fraction.

Prognostic utility of the exercise thallium-201 test in ambulatory patients with chest pain: comparison with cardiac catheterization

The goal of this study was to determine the prognostic utility of the exercise thallium-201 stress test in ambulatory patients with chest pain who were also referred for cardiac catheterization. Accordingly, 4 to 8 year (mean +/- 1SD, 4.6 +/- 2.6 years) follow-up data were obtained for all but one of 383 patients who underwent both exercise thallium-201 stress testing and cardiac catheterization from 1978 to 1981. Eighty-three patients had a revascularization procedure performed within 3 months of testing and were excluded from analysis. Of the remaining 299 patients, 210 had no events and 89 had events (41 deaths, nine nonfatal myocardial infarctions, and 39 revascularization procedures greater than or equal to 3 months after testing). When all clinical, exercise, thallium-201, and catheterization variables were analyzed by Cox regression analysis, the number of diseased vessels (when defined as greater than or equal to 50% luminal diameter narrowing) was the single most important predictor of future cardiac events (chi 2 = 38.1) followed by the number of segments demonstrating redistribution on delayed thallium-201 images (chi 2 = 16.3), except in the case of nonfatal myocardial infarction, for which redistribution was the most important predictor of future events. When coronary artery disease was defined as 70% or greater luminal diameter narrowing, the number of diseased vessels significantly (p less than .01) lost its power to predict events (chi 2 = 14.5). Other variables found to independently predict future events included change in heart rate from rest to exercise (chi 2 = 13.0), ST segment depression on exercise (chi 2 = 13.0), occurrence of ventricular arrhythmias on exercise (chi 2 = 5.9), and beta-blocker therapy (chi 2 = 4.3). The exclusion of myocardial revascularization procedures as an event did not change the results significantly. Although the number of diseased vessels was the single most important determinant of future events, the exercise thallium-201 stress test when considered as a whole (which included the number of segments demonstrating redistribution on delayed thallium-201 images, change in heart rate from rest to exercise, ST segment depression on the electrocardiogram, and ventricular premature beats on exercise) was equally powerful (chi 2 = 41.6). Combination of both catheterization and exercise thallium-201 data was superior to either alone (chi 2 = 57.5) for determining future events. Exercise stress test alone (without thallium-201 data) was inferior to the exercise thallium-201 stress test or cardiac catheterization for predicting future events (chi 2 = 30.6).(ABSTRACT TRUNCATED AT 400 WORDS)

Left ventricular dysfunction in excess of the size of infarction: a possible management strategy

In this report we describe two patients whose left ventricular dysfunction was far in excess of infarct size as evidenced by ECG changes and the magnitude of creatine kinase release. Both patients demonstrated redistribution in myocardial beds remote from the infarct zone on delayed rest thallium 201 images and both had multivessel disease evident on coronary angiography. Both patients experienced relief of symptoms and improvement in regional and global left ventricular function after revascularization surgery. The possible mechanisms of left ventricular dysfunction in myocardial beds remote from the zone of infarction are discussed.

Computer versus visual analysis of exercise thallium-201 images: a critical appraisal in 325 patients with chest pain

Although computer-aided analysis of planar thallium images has been previously reported to be superior to visual analysis, a segment-by-segment comparison of all thallium variables (presence of initial defect, presence of redistribution, and presence of abnormal lung:heart thallium ratio) has not been performed with the use of both methods. In the present study, such a comparison was performed to determine which thallium variable(s) are superior, when the computer method is used. In addition, both methods were compared to determine their correlations with the angiographic extent of coronary artery disease (no disease, or one-vessel disease vs multivessel, or left main disease) and the occurrence of future events (cardiac-related death or nonfatal myocardial infarction). Computer-aided analysis was superior to visual analysis (an average of three independent blinded observers) for detection of coronary disease because: (1) it was more specific for detecting initial defects despite having the same sensitivity (89.6% vs 91.0%, p = NS) and (2) it was more sensitive for detecting redistribution in the territory of a stenosed vessel (68% vs 46%, p less than 0.001). However, absolute myocardial clearance of thallium had very poor specificity compared to visually assessed redistribution. Only when segmental clearance was considered abnormal on a relative basis (if it was slower by 98% or more than the fastest clearing segment in the heart) did abnormal clearance achieve the same specificity (99%) and a better sensitivity (60% vs 48%, p less than 0.01) than visual analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Correlates of lung/heart ratio of thallium-201 in coronary artery disease

We studied 306 patients with chest pain (262 with coronary artery disease and 44 with no coronary artery disease) to determine which of 23 clinical, exercise, thallium, and angiographic variables best discriminate between patients with increased lung/heart ratios of thallium versus those with normal ratios. Normal lung/heart ratio values were defined using an additional 45 subjects with less than 1% probability of coronary artery disease. The number of diseased vessels was the best discriminator between patients with increased ratios versus those with normal ratios. Double product at peak exercise, number of segments with abnormal wall motion, patient gender, and duration of exercise were also significant discriminators. Using discriminant function analysis these variables could correctly identify 81% of cases with increased lung/heart ratios and 72% of cases with normal ratios. These results indicate that an increased lung/heart ratio of thallium reflects exercise-induced left ventricular dysfunction and affords a better understanding of why this thallium parameter is a powerful prognostic indicator in patients with chest pain.

Fibrin glue from stored human plasma. An inexpensive and efficient method for local blood bank preparation

European surgeons have used fibrin glue extensively during thoracic, cardiovascular, and general surgical operations. Until now, however, it has been available only as a commercial preparation made from pooled human plasma, and it has not been approved by the U.S. Food and Drug Administration for use in the United States because of a high associated risk of hepatitis and acquired immune deficiency syndrome. Methods of obtaining fibrinogen, an essential component of fibrin glue, from cryoprecipitate or fresh frozen plasma have been published recently. However, the cryoprecipitate method results in relatively low concentrations of fibrinogen, which can reduce glue effectiveness. The fresh frozen plasma method is more expensive and does not meet the standards of the American Association of Blood Banks for the "closed" system required for safe handling and management of blood component products. Both the cryoprecipitate and the fresh frozen plasma methods result in waste of unstable clotting factors. These factors are necessary to replace human plasma clotting deficiencies but are not necessary for the production of fibrin glue. The authors have developed an efficient, high-concentration blood bank method for producing and maintaining a local supply of a safer and less expensive but equally effective material derived from stored human plasma. This material is produced using approved blood bank techniques for a "closed" system in blood component production, thus reducing the risks of contamination and infection, and its fibrinogen concentration is higher than that of standard cryoprecipitate. The cost of 1 unit of this fibrin glue is comparable to that for 1 unit of cryoprecipitate and less than that for 1 unit of fresh frozen plasma.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of selectively altering collateral driving pressure on regional perfusion and function in occluded coronary bed in the dog

To determine whether selectively altering the coronary perfusion pressure in the adjacent nonoccluded vessel has any influence on the occluded bed, the effects of alterations in the perfusion pressure of the left anterior descending coronary artery on the perfusion and function of the acutely occluded left circumflex coronary (LC) arterial bed were studied in 10 anesthetized open-chest dogs. Radiolabelled microsphere-assessed regional myocardial perfusion and endocardial excursion determined by two-dimensional echocardiography were measured during control conditions prior to mid-LC occlusion with left anterior descending coronary arterial pressure (LADP) equal to aortic pressure (AoP) (Stage 0) and to 3 randomly performed postocclusion stages. At each postocclusion stage, the perfusion territory of the occluded LC bed (area at risk) was measured in vivo using myocardial contrast two-dimensional echocardiography. During Stage 1 (LADP = AoP), area at risk was 5.1 +/- 0.9 cm2 (x +/- 1 SD) and transmural blood flow to the LC arterial bed decreased from 0.96 +/- 0.50 ml/min/g (Stage 0) to 0.16 +/- 0.12 ml/min/g (p less than 0.01), while endocardial excursion decreased from 28.0 +/- 9.0% to 2.0 +/- 10.0% (p less than 0.01). During Stage 2 (LADP greater than AoP), area at risk decreased to 4.4 +/- 1.0 cm2 compared with Stage 1 (p less than 0.01), and transmural blood flow, endocardial:epicardial blood flow ratio, and endocardial excursion increased to 0.51 +/- 0.39 ml/min/g, 0.64 +/- 0.20, and 14 +/- 6%, respectively (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

The importance of defining left ventricular area at risk in vivo during acute myocardial infarction: an experimental evaluation with myocardial contrast two-dimensional echocardiography

Because the left ventricular "area at risk" is the most important determinant of ultimate infarct size, it would be useful to know the size of the area at risk during acute myocardial infarction to make therapeutic decisions. We therefore performed a series of experiments in four groups of dogs. In group I dogs (n = 15) we attempted to determine whether current methods of assessing left ventricular function during acute myocardial infarction reflect the true size of the area at risk. At each of two to five sequential stages, a more proximal coronary occlusion was performed to produce a larger area at risk until cardiovascular collapse occurred. At each stage, the area at risk (measured by myocardial contrast echocardiography), hemodynamic variables, and left ventricular ejection fraction (LVEF) were measured. Hemodynamic variables became abnormal when the area at risk was large (25% to 40% of the left ventricle), whereas LVEF became abnormal when the area at risk was of moderate size (18%). When cardiac output and LVEF were normalized to baseline values, a close inverse relationship was noted between these variables and area at risk. In contrast, there was a poor relationship between normalized mean arterial pressure and area at risk (r = .42). In group II dogs (n = 9) the area at risk was measured serially over 6 hr after coronary occlusion. The size of the area at risk remained unchanged regardless of the transmural extent of the ultimate infarct. The circumferential endocardial extent of the area at risk closely predicted the circumferential endocardial extent of the infarct at 6 hr in eight of nine dogs that developed an infarct. Group III dogs (n = 7) underwent the same protocol as group II dogs, but the duration of occlusion was 3 hr. The circumferential endocardial extent of the area at risk closely predicted the circumferential endocardial extent of the infarct. Group IV dogs (n = 5) underwent subtotal coronary occlusion. Although regional wall motion abnormalities were noted in this group, no area at risk could be defined. We conclude that although a close inverse relationship is noted between normalized cardiac output and area at risk, the absolute values for cardiac output and other hemodynamic variables become abnormal only when the area at risk is large (25% to 40%); measurement of LVEF may provide a better assessment of the size of the area at risk than hemodynamic variables.(ABSTRACT TRUNCATED AT 400 WORDS)

Free fatty acids and the binding of sulfonamides in the serum of genetically obese Zucker rat

The purpose of this study was to evaluate the serum chemistry profiles and the degree of protein binding of six sulfonamides in the sera of genetically obese Zucker rats and their lean litter mates. Free fatty acid concentrations were significantly elevated in the serum of obese rats. Obese rat serum had a mean fraction unbound for sulfanilamide, sulfadiazine, sulfapyridine, sulfamerazine, sulfisomidine, and sulfisoxazole which was significantly higher than that found in the lean rat serum. Altered serum chemistry and/or pathological states may play a significant role in altering drug protein interactions.

Quantitative aspects of myocardial perfusion imaging

Computer quantitation of myocardial perfusion images has enhanced the detection of thallium perfusion abnormalities compared to visual analysis. Computer analysis is more specific than visual analysis for detection of initial defects and more sensitive for detection of redistribution. Computer analysis is equally good for detecting thallium abnormalities in the distribution of the three major coronary arteries. Measurement of absolute clearance of thallium results in an unacceptable high false-positive rate. However, when clearance in a myocardial segment is compared to the fastest clearing segment in the heart, the specificity of clearance improves significantly. Quantitation of lung:heart ratio is very useful. Increased lung:heart ratio reflects exercise induced left ventricular dysfunction and is a strong marker of prognosis. Single photon emission computerized tomography (SPECT) offers the potential of more precisely sizing the risk area. The question of whether this technique offers a significant advantage over planar thallium imaging has to be answered.

Relationship between left ventricular systolic function and plasma clearance of 169Yb-DTPA in normal and ischemic dogs

Plasma clearance of 169Yb-DTPA, a heavy chelate metal excreted only by glomerular filtration, was measured serially in a canine model to determine whether the clearance of this substance correlates with left ventricular systolic function. Fourteen anesthetized open-chest dogs were studied. Six dogs (group I) were used to estimate the clearance of 169Yb-DTPA in the setting of normal left ventricular function. Eight dogs (group II) were used to estimate clearance of 169Yb-DTPA in the presence of ischemic left ventricular dysfunction. Cardiac output, mean arterial pressure, and plasma levels of 169Yb-DTPA were measured serially. In group II dogs, area at risk for necrosis was defined using myocardial contrast echocardiography. The change in clearance of 169Yb-DTPA in group II dogs correlated well with change in cardiac output and area at risk (r = 0.80 and -0.93, respectively) and was significantly different from group I dogs (p less than 0.01). However, changes in clearance of 169Yb-DTPA in the group II dogs did not correlate well with change in mean arterial pressure (r = 0.26).

IN CONCLUSION

(1) clearance of 169Yb-DTPA is constant over time in the absence of ischemic left ventricular dysfunction and derangement of other hemodynamic parameters; (2) changes in clearance of 169Yb-DTPA correlate well with changes in systolic pump function and left ventricular area at risk in the setting of ischemic left ventricular dysfunction, and (3) clearance of 169Yb-DTPA is not related to mean arterial pressure.

Myocardial contrast echocardiography in humans: I. Safety--a comparison with routine coronary arteriography

Myocardial contrast echocardiography is a new diagnostic cardiovascular imaging technique capable of defining perfusion zones of coronary vessels in vivo; ultimately, it may be used to measure absolute regional myocardial blood flow. However, before it can be used in humans, its safety must be clearly established. Accordingly, the electrocardiographic and hemodynamic effects of intracoronary injections of 2 cc of sonicated Renografin-76 were compared with 5 to 10 cc of non-sonicated Renografin-76 in 10 subjects with normal coronary arteries. Two cubic centimeters of sonicated Renografin provides optimal myocardial opacification during echocardiography, while 5 to 10 cc of Renografin is required for an adequate coronary arteriogram. During coronary arteriography, heart rate decreased while PR and QT intervals and QRS duration increased as compared with baseline and myocardial contrast echocardiography (p less than 0.01). Similarly, the decrease in aortic pressure and first derivative of left ventricular pressure (dP/dt) was significantly (p less than 0.01) greater during routine coronary arteriography than during myocardial contrast echocardiography. Changes in left ventricular end-diastolic or pulmonary capillary wedge pressure were similar during myocardial contrast echocardiography and coronary angiography. There were no significant differences in the duration of electrocardiographic and hemodynamic changes between myocardial contrast echocardiography and coronary arteriography. It is concluded that intracoronary injection of 2 cc of sonicated Renografin-76 provides optimal myocardial opacification. It is safe in humans, producing transient electrocardiographic and hemodynamic alterations that are less pronounced than those seen during routine coronary angiography.