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Biomedical subjects

D Schlossman

Publications and source records attributed to D Schlossman.

At least 19 recordsLinked to original sources
PubMed1993

Image intensifier based digital chest radiography. Visibility of lesions and anatomy.

Contrast- and edge-enhanced digital monitor images from an image intensifier system for chest radiography were compared to conventional radiograms using visual grading analysis. Eleven observers graded the visibility of rounded opacities, the carinal region, fine line structures, and also compared the overall quality of images from 20 patients. The results showed significantly better visibility on the digital monitor for the rounded opacities and the mediastinum compared to the conventional radiograms. The overall quality of the digital images was also considered better. However, the digital images showed significantly inferior visibility for the line structures in comparison with the conventional radiograms. Our study indicates that the present contrast- and edge-enhanced digital images, with a spatial resolution of 1,024 x 1,024 pixels and a contrast resolution of 8 bits, are superior to conventional radiograms for the visualization of mediastinal anatomy and rounded opacities. The clinical importance of the inferior visibility of fine line structures is not clear.

Adult↗
PubMed1991

Epidermal growth factor receptor expression in normal ovarian epithelium and ovarian cancer. II. Relationship between receptor expression and response to epidermal growth factor.

Previously we have shown that epidermal growth factor acts as a mitogen for some, but not all, ovarian cancer cells in culture. In this study we examined the effect of epidermal growth factor on proliferation of normal human ovarian epithelial cells in monolayer culture. We found that epidermal growth factor stimulated twofold to fourfold increases in proliferation in epithelial cells from each of five normal ovaries (p less than 0.01). In addition, Scatchard analysis of binding of epidermal growth factor tagged with iodine 125 indicated the presence of high-affinity receptors in all of the ovarian epithelial cells and ovarian cancer cell lines. The number and affinity of receptors was similar in the normal epithelium and cancer cell lines, and there was no relationship between epidermal growth factor receptor number and responsiveness to epidermal growth factor. We conclude that human ovarian epithelial cells normally express epidermal growth factor receptors and that epidermal growth factor acts as a mitogen for these cells. Although the mitogenic response to epidermal growth factor often is attenuated in ovarian cancer cell lines, loss of responsiveness to epidermal growth factor does not appear to be due to decreased receptor expression.

Cells, Cultured↗
PubMed1990

Chest radiography in the intensive care unit. Indications for radiography and effects of selective archiving of films.

Consecutive chest radiographs (n = 2,303) in 601 patients in the intensive care units (ICU) were analyzed with regard to main disease and indication. Two thirds of the patients were transferred for routine post-operative treatment, 14 per cent mainly for cardiopulmonary insufficiency. The remainder were referred because of various clinical conditions. The main indications for chest radiography were routine radiographic follow-up and/or control of the position of catheters, tubes, drainages etc. (50%). Obvious clinical indications appeared in only about 1/4 of the patients. When the patients were discharged from the ICU all chest radiographs were analyzed with regard to their predicted future value. Films considered not worth storing were removed and stored in a separate archive (57%). During a 15-month follow-up period none of the removed films were requested, indicating that a substantial number of films can be sorted out continuously. The possibility to reduce and to 'clinically compress' the amount of data in a future digital picture archive is emphasized.

Humans↗
PubMed1989

Role of glutamic acid 177 of the ricin toxin A chain in enzymatic inactivation of ribosomes.

The gene for the A chain of ricin toxin was fused to a beta-galactosidase marker cistron via a DNA sequence encoding a short collagen linker, and the tripartite fusion protein was expressed in Escherichia coli. Site-specific mutagenesis was used to change glutamic acid residue 177 to aspartic acid or alanine. When the mutant proteins were expressed, purified, and tested quantitatively for enzymatic activity, the carboxylate function at position 177 was found not to be absolutely essential for ricin toxin A-chain catalysis.

Blotting, Western↗
PubMed1989

Selection and characterization of ricin toxin A-chain mutations in Saccharomyces cerevisiae.

A DNA sequence encoding the A chain of ricin toxin (RTA) from the castor bean plant, Ricinus communis, was placed under GAL1 promoter control and transformed into Saccharomyces cerevisiae. Induction of expression of RTA was lethal. This lethality was the basis for a selection of mutations in RTA which inactivated the toxin. A number of mutant alleles which encoded cross-reactive material were sequenced. Eight of the first nine mutant RTAs studied showed single-amino-acid changes involving residues located in the proposed active-site cleft.

Amino Acid Sequence↗
PubMed1989

Digital chest radiography with a large image intensifier. An ROC study with an anthropomorphic phantom.

The diagnostic performance of two systems for chest radiography was studied. One system was based on a large image intensifier, the other was a conventional film-screen system. The images from the image intensifier were studied either on a digital TV screen or on 100 mm photofluorograms. Receiver operating characteristic curve analysis was performed on images of an anthropomorphic chest phantom. Low-contrast MMAP (methyl methacrylate polymer) nodules and simulated vessels were positioned over the parenchymal and the mediastinal region of the phantom. Five observers assessed the digital monitor images, photofluorograms, and conventional full-size radiograms. The results showed a significantly superior detectability for the full-size radiograms over the digital monitor images both in the parenchyma and in the mediastinum. No significant difference was found between photofluorograms and digital images.

Humans↗
PubMed1988

Cardioangiographic findings in patients with arrhythmogenic right ventricular dysplasia.

The dimension, contractility, and regional wall motion of the right and left ventricles were scored on the angiograms of 13 patients with arrhythmogenic right ventricular dysplasia. In 10 patients the right ventricle was enlarged, in eight the contractility of the right ventricle was reduced, and in all but one patient there were regional wall motion abnormalities of the right ventricle. The most common abnormality of regional wall motion was mild hypokinesia. There were bulging or dyskinetic areas in seven patients. Regional wall motion abnormalities of the left ventricle were found in five patients, two of whom also had bulging or dyskinetic areas. The reproducibility of right ventricular dimension, contractility, and regional wall motion scores was generally fair but varied unexpectedly both within and between two observers (Kendall's Tau 0.38-0.92). The score values of regional wall motion for some of the segments differed considerably within and between observers. One of the observers consistently gave higher scores than the other. These data suggest that a more objective approach is needed for evaluating angiographic changes in arrhythmogenic right ventricular dysplasia.

Adolescent↗
PubMed1986

Felodipine-induced dilatation of epicardial coronary arteries. A randomized, double-blind study.

Dilatation of large coronary arteries is of potential value in the treatment of angina pectoris. In this double-blind study, the acute effect of felodipine or placebo on coronary artery dilatation was studied in patients with severe angina pectoris with the aid of coronary arteriography. There were two parallel groups, one with 9 patients who received felodipine, the other with 12 patients who received placebo. Measurements of vessel diameters were performed at a proximal position of the affected artery, at the site of the stenosis, and distal to the lesion. The mean plasma felodipine concentration was 17+/-6 nmol/l. The systolic blood pressure was reduced from 156+/-15 to 145+/-13 mm Hg after felodipine (p less than 0.05), but was unaffected by placebo. The heart rate and arterial catecholamine levels were basically unchanged in both groups of patients. The proximal arterial segment was dilated 7% after felodipine (p = 0.05), the stenosis area 9% (N.S.) and the distal part of the vessel 7% (p less than 0.05). There were no changes in coronary diameters in the placebo group. In conclusion, felodipine dilates large coronary arteries, and this mode of action may be valuable in the treatment of patients with coronary artery disease, especially in cases where coronary spasm is a prominent feature.

Adult↗
PubMed1985

Fentanyl-droperidol-nitrous oxide anaesthesia in patients with ischaemic heart disease and various degrees of left ventricular functional impairment.

Haemodynamic stability and left ventricular function (LVF) during induction of anaesthesia and sternotomy were compared in three groups of patients with ischaemic heart disease, angiographically classified as having good, poor and depressed LVF. Anaesthesia was given with fentanyl-droperidol and nitrous oxide. The group with good LVF showed large variations in arterial pressure and heart rate between stimulated and unstimulated states with a reasonable preservation of LVF, expressed as stroke volume, through the whole observation period. The group with poor LVF showed monotonously falling arterial pressure, and no heart rate response to tracheal intubation. These patients maintained remarkably stable stroke volumes in connection with low afterloads. After nitrous oxide, additional volume loading was required because of profound hypotension. The majority of the patients in the intermediate group, labelled "depressed LVF", reacted to intubation and sternotomy with signs of left ventricular failure in connection with tachycardia and increased afterloads. The individual variations between patients with different degrees of left ventricular impairment were considerable, and these haemodynamic patterns need to be confirmed with a larger material.

Anesthesia, General↗
PubMed1984

Sex differences in cardioangiographic findings after myocardial infarction.

The cardioangiographic findings in 50 women 40-54 years of age were compared with those of a series of 69 men with infarction recruited from the same catchment area and investigated according to the same principles. Women less often had left ventricular abnormalities than men; this difference was mainly confined to patients with non-Q wave infarctions. There was no difference in the prevalence of left ventricular abnormalities among women and men with Q wave infarctions. No major sex difference was found in the prevalence of coronary abnormalities. Collaterals were less common in women than in men.

Adult↗
PubMed1984

Computer aided exercise electrocardiographic testing and coronary arteriography in patients with angina pectoris and with myocardial infarction.

A set of electrocardiographic criteria for the diagnosis of coronary artery disease was evaluated in two different groups of patients examined by computer aided 12 lead exercise electrocardiographic stress testing and coronary arteriography. One group consisted of patients with severe angina pectoris and the other of patients who had suffered a myocardial infarction three years before the study. Angiographically determined categories of patients could be identified with satisfactory precision by the electrocardiographic criteria under test in the patients with angina pectoris but not in those with infarction. A new method of classifying patients on the basis of data from coronary arteriography improved the correlation with ST segment analysis compared with conventional classification.

Adult↗
PubMed1983

Myocardial protective effect of maintained beta-blockade in aorto-coronary bypass surgery.

Twenty-nine patients were randomly allocated to two groups before undergoing aorto-coronary bypass surgery. In one group the beta-blocking medication was withdrawn three days preoperatively, and in the other group it was maintained. The patients in the latter group were additionally given 100 mg metoprolol per os two hours before surgery. The degree of myocardial injury, as judged from cumulated activity of S-CK B, was less when the beta-blockade was maintained.

Adrenergic beta-Antagonists↗
PubMed1983

Strut fractures in De Bakey aortic valves.

In two of six patients with a De Bakey aortic valve prosthesis implanted in 1973, strut fractures occurred after 7.5 and 9 years, respectively. In one case the cage and ball embolized and the outcome was fatal. The second case was recognized before embolization had occurred, and the valve could be successfully replaced. Valve replacement is recommended in cases with a De Bakey aortic prosthesis of the described type.

Aortic Valve↗
PubMed1982

Computerized exercise ECG in the diagnosis of critical coronary lesions.

Different ECG criteria are evaluated with respect to their ability to identify individuals with critical lesions of the coronary arteries in a population of patients with severe angina. Six chest leads and the the limb leads were recorded in 85 patients by computer during maximal, symptom-limited exercise ECG testing. Averaging of ECG complexes enhances the signal quality and makes it possible to use measurements of the limb leads recorded during exercise. 14 patients with abnormal Q waves in lead V2 were excluded from ST analysis. In the remaining 71 patients, more than 1/3 mm ST depression in lead I and/or more than 2.0 mm ST depression in any of the chest leads had a sensitivity of 85% and a specificity of 67% for lesions in the main stem and/or proximal LAD and/or three-vessel disease. The predictive value of a positive test was 83%. This and other criteria were evaluated for different disease groups and a different stages during the exercise test.

Adult↗
PubMed1980

The diagnosis of atrial myxomas. Difficulties and pitfalls.

Altogether seven patients with the preoperative diagnosis of atrial myxoma were admitted to our hospital in 1968-78 and referred for surgery. In two patients no tumour was found at operation. In one of them the reason for the misinterpretation was severely malformed mitral leaflets. In the other the contrast medium was injected into a pulmonary vein, which caused a contrast defect due to inadequate mixing.

Adult↗