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Biomedical subjects

B Freedman

Publications and source records attributed to B Freedman.

At least 73 records · Page 4Linked to original sources
PubMed1984

Myocardial ischemia during ergonovine testing: different susceptibility to coronary vasoconstriction in patients with exertional and variant angina.

Coronary spasm is an accepted cause of transient myocardial ischemia in patients with variant angina; more recently it has been suggested that dynamic stenoses could also play an important role in the pathophysiology of exertional angina. To test this hypothesis we submitted 31 patients with histories typical of exertional angina to ergonovine testing and compared the electrocardiographic and clinical responses to those observed in seven patients with variant angina. All underwent bicycle ergometric exercise testing and coronary angiographic examination. For all tests, ST segment shifts of 0.1 mV or greater were considered to be diagnostic of myocardial ischemia. In patients with exertional angina, exercise testing produced diagnostic ST segment depression in 21 (68%). Ergonovine testing produced diagnostic ST segment depression in nine (29%). All nine had positive exercise test results and two- or three-vessel disease, yet the test was negative in seven other patients with positive exercise test results and similar angiographic findings. Conversely, in the seven patients with variant angina, results of exercise testing were positive in five (ST segment depression in two, ST elevation in three), while ergonovine produced ST segment elevation in all seven. Coronary angiographic examination showed normal arteries in two, one-vessel disease in four, and three-vessel disease in one. Results of all ergonovine tests were positive at values of rate pressure product much lower than those observed during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Protein concentrations in fluid from gross cystic disease of the breast.

Wide variations in the concentrations of IgA, IgG, lactoferrin, lysozyme and albumin were found in 96 cyst fluids obtained from 75 patients with gross cystic disease of the breast. Sedimentation coefficient determination were performed on 19 of the cyst fluids with the highest IgA concentrations in an attempt to discover the basis for the wide variation and two types of cyst fluids were found: cyst fluids that resembled external secretions such as colostrum of milk with the IgA wholly or predominantly in the 11S (secretory) form, and low concentrations of IgG and albumin, and cyst fluids that resembled serum with the IgA wholly or predominantly in the 7S (serum) form, and high concentrations of IgG and albumin. Some cyst fluids contained low concentrations of all proteins measured, and no relationship was observed between the concentrations of the proteins studied, and age, parity or menstrual status.

Adult↗
PubMed1983

Impairment of myocardial perfusion and function during painless myocardial ischemia.

Left ventricular (or pulmonary and systemic arterial) hemodynamics were measured for a mean of 13.6 hours during continuous electrocardiographic monitoring in 14 patients admitted to the coronary care unit because of angina at rest. Of 293 episodes of transient ST segment and T wave changes identified, 247 (84%) were completely asymptomatic. Sixty-three percent of asymptomatic episodes were associated with an elevation of the left ventricular end-diastolic or pulmonary artery diastolic pressure of 5 mm Hg or more; in 15% there were smaller elevations (2 to 4 mm Hg) and in 22% there were no changes or less than a 2 mm Hg elevation of pressure. The peak contraction and relaxation dP/dt (first derivative of left ventricular pressure) were reduced to 100 mm Hg/s or more in 84 and 81% of asymptomatic episodes, respectively. Great cardiac vein oxygen saturation measured in three patients showed an increased myocardial oxygen extraction similar to that seen in painful episodes, which preceded and accompanied asymptomatic electrocardiographic changes. These results indicate that asymptomatic electrocardiographic changes represent transient myocardial ischemia. Comparison of asymptomatic and symptomatic episodes revealed that asymptomatic episodes were generally shorter (253 +/- 159 versus 674 +/- 396 seconds, probability [p] less than 0.001) and produced less impairment of left ventricular function: there were smaller elevations of left ventricular end-diastolic or pulmonary artery diastolic pressure (5.9 +/- 5.0 versus 16.5 +/- 6.9 mm Hg, p less than 0.001), and smaller reductions of peak left ventricular contraction dP/dt (252 +/- 156 versus 395 +/- 199 mm Hg/s, p less than 0.001) and relaxation dP/dt (259 +/- 191 versus 413 +/- 209 mm Hg/s, p less than 0.001). In individual patients, however, asymptomatic and symptomatic episodes of similar duration and severity were observed. The duration and severity of ischemia appear important for the genesis of anginal pain, but additional factors must be involved.

Adult↗
PubMed1983

Oestrogen receptor activity and intranuclear translocation of oestradiol in rat and human mammary tumours.

Forty-eight rat mammary tumours and 25 human breast carcinomata were examined for (a) oestrogen receptor activity and (b) capacity for intranuclear translocation of oestrogen. Receptor activity was determined by saturation analysis using charcoal adsorption to separate free and bound hormone. The capacity for intranuclear translocation was determined by incubation of tumour slices in Krebs-Ringer bicarbonate solution containing [3H]oestradiol-17 beta at a physiological concentration, in the presence and absence of a large excess of non-radioactive oestradiol, at 37 degrees C. Saturable nuclear uptake of [3H]oestradiol (= translocation) in boiled or receptor-negative tissues was minimal, i.e. less than 12 fmol/mg DNA per 2 h and in receptor-positive tissue was reduced by 85% when the temperature was lowered to 0 degree C. In 27 ovary-independent transplantable tumours and 21 dimethylbenz(a)anthracene-induced tumours (predominantly ovary dependent) saturable nuclear uptake was strongly correlated with level of oestrogen receptor activity (Spearman's rank correlation coefficient r = +0.73, P less than 0.001). Nineteen of these 48 tumours were examined further: 60-80% of the saturable uptake was precipitable with protamine sulphate and this fraction of the total saturable uptake was also highly correlated with receptor level (Spearman's r = +0.87, P less than 0.001). In the 25 human tumours studied, saturable nuclear uptake was again correlated with receptor level (Spearman's r = +0.75, P less than 0.001). These studies suggest that saturable transfer of oestradiol from the extracellular medium through the cytoplasm to the cell nucleus is mediated by the oestrogen receptor in the rat and human tumours examined. They provide no evidence for any defect of the receptor mechanism before nuclear binding in tumours which are receptor positive but hormone insensitive.

Animals↗
PubMed1982

Pathophysiology of coronary artery spasm.

Coronary arterial measurements were made from cineangiograms in patients with positive and negative ergonovine tests. In those with positive tests, normal segments of arteries adjacent to the site of spasm and arteries without spasm showed no greater sensitivity to ergonovine than arteries from control patients (20 +/- 13% constriction vs 17 +/- 12%, NS). In patients with positive and negative ergonovine tests, constriction was measured at lesion sites after ergonovine and compared with values predicted from a geometric theory. The measured constriction was always greater than predicted in patients with a positive ergonovine test, and frequently less than predicted in patients with a negative test. The increased sensitivity of arteries that show localized vasospasm at lesion sites after ergonovine administration is not explained by geometry alone.

Adult↗
PubMed1981

Localization of coronary artery disease with exercise electrocardiography: correlation wit thallium-201 myocardial perfusion scanning.

In 61 patients with single vessel coronary artery disease (70 percent or greater obstruction of luminal diameter in only one vessel) and no previous myocardial infarction, the sites of ischemic changes on 12 lead exercise electrocardiography and on thallium-201 myocardial perfusion scanning were related to the obstructed coronary artery. The site of exercise-induced S-T segment depression did not identify which coronary artery was obstructed. In the 37 patients with left anterior descending coronary artery disease S-T depression was most often seen in the inferior leads and leads V4 to V6, and in the 18 patients with right coronary artery disease and in the 6 patients with left circumflex artery disease S-T depression was most often seen in leads V5 and V6. Although S-T segment elevation was uncommon in most leads, it occurred in lead V1 or a VL, or both, in 51 percent of the patients with left anterior descending coronary artery disease. A reversible anterior defect on exercise thallium scanning correlated with left anterior descending coronary artery disease (probability [p] less than 0.0001) and a reversible inferior thallium defect correlated with right coronary or left circumflex artery disease (p less than 0.0001). In patients with single vessel disease, the site of S-T segment depression does not identify the obstructed coronary artery; S-T segment elevation in lead V1 or aVL, or both, identifies left anterior descending coronary artery disease; and the site of reversible perfusion defect on thallium scanning identifies the site of myocardial ischemia and the obstructed coronary artery.

Coronary Disease↗
PubMed1981

Toxicity of Bacillus thuringiensis Spo Cr Mutants for the European Corn Borer Ostrinia nubilalis.

Inclusion bodies isolated from Spo Cr mutants of Bacillus thuringiensis were toxic for larvae of the European corn borer. Probit analysis revealed comparable toxicity between wild-type crystals (isolated from B. thuringiensis subsp. kurstaki) and crystals produced from two spore-free mutants of the same subspecies. Death of the larvae was due to starvation, presumably through delta-endotoxin-induced gut paralysis. Inclusion bodies pretreated with alpha-chymotrypsinogen were equally as toxic as native crystals for the insect larvae.

Journal Article↗
PubMed1981

Exercise-induced ST-segment elevation in leads V1 or aVL. A predictor of anterior myocardial ischemia and left anterior descending coronary artery disease.

Exercise-induced ST-segment elevation in leads V1 and/or aVL in the absence of anterior Q waves occurred in 46 of 190 patients (24%) who underwent 12-lead exercise electrocardiography with thallium-201 myocardial perfusion imaging and coronary arteriography. Significant left anterior descending coronary artery (LAD) disease was present in 38 of 46 patients (83%) with V1/aVL ST evaluation and in 72 of 144 patients (50%) without V1/aVL ST elevation (p less than 0.0005). Anterior myocardial ischemia, indicated by reversible anterior perfusion defects on thallium scanning, was present in 40 of 46 patients (87%) with V1/aVL ST elevation and in 25 of 144 patients (17%) without V1/aVL ST elevation (p less than 0.0005). Exercise ST elevation in V1/aVL was detected in 38 of 110 of the patients (35%) with LAD disease, for a specificity of 90%, and in 40 of 65 of the patients (62%) with anterior myocardial ischemia, for a specificity of 95%. We conclude that during 12-lead exercise electrocardiography, ST-segment elevation in V1 and/or a VL in the absence of anterior Q waves predicts anterior myocardial ischemia and LAD disease.

Arterial Occlusive Diseases↗
PubMed1981

Coronary artery spasm during exercise: treatment with verapamil.

Six patients who had documented coronary spasm and no coronary artery with organic obstruction greater than 50% developed angina and ST-segment elevation on exercise testing. Oral verapamil, 160-480 mg/day, prevented exercise-induced ischemia in all patients and increased maximal work capacity from 611+/- 250 kpm to 808 +/- 160 kpm (p less than 0.02). In two patients, a relationship between the prevention of exercise-provoked ischemia and the plasma concentration of verapamil was demonstrated, and in one of these, the relationship had a diurnal pattern. Patients with variant angina may develop coronary spasm on effort and often respond to verapamil.

Angina Pectoris↗