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Biomedical subjects

B Freedman

Publications and source records attributed to B Freedman.

At least 91 records · Page 5Linked to original sources

Coronary spasm management with verapamil (Isoptin).

Because of recurrent chest pain, 17 patients with documented spasm in coronary arteries without severe atherosclerotic obstructions were treated with verapamil in an open trial, using doses of 120 mg/day to 480 mg/day (mean, 240 mg/day). Thirteen patients received additional oral isosorbide dinitrate (30 mg/day). Eleven patients became asymptomatic, and four experienced marked reduction in frequency of attacks (one to four a month). While two patients did not respond, in most patients verapamil was effective in preventing attacks of angina due to coronary spasm.

Administration, Oral↗

The value of exercise electrocardiography and exercise thallium-201 myocardial perfusion scanning in determining the presence of single vessel coronary artery obstruction.

In 39 patients with single vessel coronary artery disease and no previous myocardial infarction, exercise thallium-201 myocardial perfusion scanning and 12 lead exercise electrocardiography (ECG) were compared to see how reliably each method identified the site of coronary artery obstruction. Significant (greater than or equal to 70% diameter) stenosis was present in the left anterior descending (LAD) coronary artery in 21 patients, in the right coronary artery (RCA) in 14 patients and in the left circumflex (LCX) in four patients. Thallium defects on the scan in the septal (SEPT), anteroseptal (ANT SEPT) and anterior (ANT) segments correlated (P less than 0 . 0005) with LAD disease and defects in the inferior (INF), posteroinferior (POST INF), and posterior (POST) segments correlated (P less than 0 . 0005) with RCA or LCX disease. Exercise induced ST segment elevation in VI and/or AVL correlated with LAD disease. The site of ischaemic ST depression did not correlate with disease in any vessel. ST segment depression in leads L2, 3, AVF (67%) and in leads V4--6 (67%) was most sensitive for detecting patients with LAD disease and ST depression in leads V4--6 was most sensitive (56%) for detecting patients with RCA or LCX disease but neither differentiated LAD from RCA/LCX disease.

Adult↗

Noninvasive prediction of multivessel disease after myocardial infarction.

In 65 patients with a previous transmural myocardial infarction (anterior in 33, inferior in 32), exercise thallium scanning was compared with 12-lead exercise electrocardiography to see if multivessel disease could be detected. At coronary arteriography 40 patients were shown to have multivessel disease ( greater than or equal to 70% diameter stenosis in two or three vessels) and 25 patients had one-vessel disease. On the exercise scan thallium defects corresponding to the electrocardiographic site of infarction were present in all patients. Patients wih one-vessel and multivessel disease were separated by exercise-induced angina, perfusion defects on the exercise thallium scan in more than one specific vasculare area, and a positive exercise ECG associated with angina, but not by a positive exercise ECG alone. Of the 40 patients with multivessel disease, 85% had defects in more than one vascular area on the thallium scan and 70% had a positive exercise ECG (p = NS). Of the 37 patients with thallium defects in more than one specific vascular area, 92% had multivessel disease, compared with 72% of the 39 patients who had a positive exercise ECG (p < 0.05). periinfactional ischemia was present in 38 of the 65 patients (58%) ( 14 of 25 with one-vessel disease and 24 of 40 with multivessel disease), and did not correlate with the severity of the corresponding coronary artery disease. When thallium defects that resolved were noted in a second vascular area, they were associated with a resolving rather than a constant defect in the vascular area where the infarction had occurred ( p < 0.005). In patients after a transmural myocardial infarction, multivessel disease can be better differentiated from one-vessel disease by thallium scanning than by exercise electrocardiography.

Adult↗

Sedimentation profiles of the oestrogen receptor from breast tumours of man and rat using vertical-tube rotor centrifugation.

In rat mammary tumours and uteri it was found that reaction time, ionic strength, reproductive state and storage in liquid nitrogen affected the form of the oestrogen receptor detected by sucrose density-gradient analysis using a vertical-tube rotor. A standard method of gradient analysis was defined. The sedimentation profile of the oestrogen receptor was compared in three types of experimental rat mammary tumour of known hormonal sensitivity. These were two lines of ovary-independent transplantable tumours and those tumours induced by dimethylbenz(a)anthracene (DMBA) which are mainly ovary-dependent. In all three types of tumour the 8S receptor was the predominant molecular form (32 out of 36 tumours induced by DMBA and 11 out of 13 transplantable tumours). Sedimentation profiles of the oestrogen receptor were also examined in 46 human breast carcinomata found to be receptor-positive by the dextran-coated charcoal technique. Of these, 17 were found to be receptor-negative by gradient analysis and 28 out of 29 receptor-positive tumours contained 8S receptor. It was concluded that (1) 8S receptor is the predominant molecular form in both human and rat mammary tumours, (2) molecular form of receptor is not related to ovarian dependence in these rat mammary tumours and (3) gradient analysis seems unlikely to provide additional discrimination in the prediction of response to endocrine therapy over that provided by simpler methods.

Animals↗

Exercise thallium imaging: location of perfusion abnormalities in single-vessel coronary disease.

Exercise-induced thallium defects were segmentally analyzed in four standard views (anterior, 40 degrees left anterior oblique, 60 degrees left anterior oblique, and left lateral) and correlated with the arteriographic findings in 49 patients with single-vessel disease (> 70% diameter narrowing). Defects in the septal (SEPT), anteroiseptal (ANT SEPT), and anterior (ANT) segments correlated (p < 0. 0005) with stenosis of the left anterior descending coronary artery (LAD). For LAD disease the ANT SEPT segment had the highest sensitivity (84%) and specificity (100%). Defects in the inferior (INF), posteroinferior (POST INF), and posterior (POST) segments correlated (p < 0.0005) with either right (RCA) or circumflex (LCX) stenosis. For RCA or LCX disease, the POST segment had the highest sensitivity (82%) and specificity (100%). The site of single-vessel coronary artery disease can be accurately predicted noninvasively by segmental analysis of thallium images in four anatomical projections.

Adult↗

Reproducibility of measurements of oestrogen-receptor concentration in breast cancer.

The reproducibility of measurements of oestrogen-receptor activity has been examined in multiple specimens from a rabbit uterus, a rat mammary tumour and human breast tumours. The relationship between receptor concentration and tumour histology has also been investigated in 11 large primary tumours. In the animal tissues, receptor measurements were relatively reproducible (coefficient of variance: wet wt. basis 16-17%, protein basis 16-21%) but in human breast tumours receptor activity varied considerably (c.v.: wet wt. basis, 22-125%; protein basis, 28-72%). In addition to these variations in receptor activity within tumours, there was a difference between tumours, as demonstrated by an analysis of variance (P less than 0.01). In the 11 primary breast cancers selected for study, the level of receptor activity was related to menopausal status and the tumour content of the specimen. We conclude that the receptor activity detected varies within a tumour and depends upon the tumour content of the biopsy specimen. Predictions based on precise quantitation of receptor concentrations may therefore necessitate replicate tumour sampling and correction for the fraction of non-tumour tissue in each sample.

Animals↗

Plasma hormone levels and the incidence of carcinogen-induced mammary tumours in two strains of rat.

The incidence of mammary tumours developing after administration of the carcinogen DMBA (at 50 days of age) has been determined in 2 strains of Sprague-Dawley rat. Untreated animals of each strain were exsanguinated in dioestrus at a time corresponding to the early post-carcinogen stage (at 70 days of age) and the plasma concentrations of prolactin, oestradiol-17B and progesterone were measured by radioimmunoassay. In an inbred strain of rats, tumour-induction rate was 6-4% and plasma prolactin concentration was 2-5 x lower than that found in a random-bred strain with a tumour-induction rate of 41-6%. No difference was found between the 2 strains in the level of either ovarian hormone. It is concluded that the difference between these strains in mammary gland susceptibility to DMBA may be related to plasma prolactin concentration, but it is unlikely to be determined by the ovarian hormones.

9,10-Dimethyl-1,2-benzanthracene↗