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Biomedical subjects

A Marmur

Publications and source records attributed to A Marmur.

13 recordsLinked to original sources

Dietary intervention in breast cancer patients: effects on food choice.

Effects of dietary intervention on food choice were studied in 240 women aged 50-65 years who had been operated for a stage I-II breast cancer. Following surgery, the women participated in a dietary history interview and were then randomized to one of two groups. The intervention group (n = 121) received individual dietary counselling aimed at reducing dietary fat intake to 20-25% energy (E%), whereas no dietary advice was given to women in the control group (n = 119). For the 52% of the women in the intervention group that completed the study the total fat intake decreased from 36 to 23 E% (P less than or equal to 0.01) and from 37 to 34 E% (P less than or equal to 0.01) for the control group. There were significant reductions in the intake of table fat, high-fat milk products, pork and sausages (containing greater than 11% fat), eggs, rice, pasta, cakes and chocolate for the intervention group. Concurrently the intake of vegetables, fruits, potatoes, bread, cereals, low-fat milk products, low-fat meat, sausages and fish increased significantly. For the control group there was a significant decrease in the consumption of total milk products, total meats, rice, pasta, cakes, and butter intake while the consumption of vegetables, fruits, cereals and fish increased (P less than or equal to 0.01). Reduction of high-fat foods and increases of carbohydrate-rich foods were more pronounced for the intervention group than for the control group. Formal education influenced dietary changes, and dietary counselling should therefore ideally be adapted to education level. This study showed that dietary counselling can bring about significant changes in consumption of high-fat foods for at least a 2-year period for women operated for breast cancer.

Breast Neoplasms

Sialic acid of platelets and granulocytes in polycythemia vera.

Previous studies have shown that erythrocytes of polycythemia vera (PV) patients have an increased content of sialic acid on their membrane compared with normal erythrocytes. This has been attributed to the presence of an abnormal clone known to proliferate in this disease. Since granulocytes and platelets originate from the same stem cell that is involved in this disease, it was of interest to see whether these cells also bear increased amounts of sialic acid compared with their normal counterparts. While normal values were found for granulocyte populations, elevated values were found for the platelet populations of PV patients.

Blood Platelets

A model of deposition and embolization of proteins and platelets on biomaterial surfaces.

A theoretical model for the deposition and detachment of protein and platelets on biomaterial surfaces is presented here. This work is an extension of the model previously reported. Two mechanisms of protein and platelet removal are assumed: A characteristic time elapses before adsorbed protein detaches from the surface, carrying away platelets and protein which have deposited on top of it; and thrombi that attain a critical size are subject to hydrodynamic forces which embolize them from the surface. A theoretical distribution of thrombus sizes is assumed. Analysis of the effects of varying model parameters on predicted protein and platelet deposition reveals that the addition of the embolization process does not change the overall structure of the deposition profiles, but does significantly affect the finer details.

Adsorption

Platelet adhesion in hyperlipidemic and hypertensive patients.

Platelet adhesion was studied in whole blood using a simple stagnation flow method in patients at high risk for the development of atherosclerosis. Fourteen patients with hypercholesterolemia, 26 with hypertriglyceridemia and 25 normolipidemic hypertensive subjects were compared with 75 normal (normotensive and normolipidemic) subjects. Increased platelet adhesion was found in hypercholesterolemic (but not hypertriglyceridemic) patients only when native blood with no anticoagulants was used. In hypertensive patients, platelet adhesion was significantly elevated, but remarkably reduced by beta-blocker drugs. Propranolol and atenolol significantly reduced platelet adhesion, but this effect was found to take a longer time than that required for significant blood pressure reduction.

Adult

Platelet adhesion determination in whole blood using a simple stagnation flow method.

A simple stagnation flow method for the determination of platelet adhesivity has been developed. The sensitivity of the method to its main operational parameters was tested, resulting in recommended standard flow conditions. The method was shown to be dependent on the surface properties of the test slide, on which platelets are deposited, thus proving its suitability to elucidate variations in the surface interaction of the platelets. Normal values were established for males and females.

Adult

The roles of serum myoglobin, total CPK, and CK-MB isoenzyme in the acute phase of myocardial infarction.

Frequent blood samples were drawn for determination of serum myoglobin, creatine phosphokinase (CPK), and the MB isoenzyme of CPK (CPK-MB) in patients with acute myocardial infarction (AMI). Significantly elevated levels of myoglobin were present 1.5 hours following onset of chest pain and predated elevations of CPK and CPK-MB by 3 hours. No evidence of the previously described "staccato" phenomenon was found. Due to very frequent blood sampling, a detailed picture of the evolution over time of the above indices was obtained. Significant differences were found in the biochemical profile of anterior wall infarction and diaphragmatic wall MI. A time-sensitivity curve (showing sensitivity of the assay at each time following onset of symptoms) was obtained for myoglobin, CPK, and CPK-MB. It appears that myoglobin is the most sensitive biochemical indicator of AMI in its early phase and since it decreases rapidly back to normal values, it can serve as an invaluable aid in the diagnosis of reinfarction and infarct extension. CPK-MB is a less sensitive indicator of MI but has the advantage of greater specificity.

Acute Disease

Moving boundary electrophoresis and sialic acid content of normal and polycythaemic red blood cells.

Moving boundary electrophoresis has been used for the assessment of the negative charge on erythrocyte membranes. The equipment is easy to construct and simpler to use than the microelectrophoresis technique. There is a direct relationship between the electrophoretic velocity measured by the moving boundary method and the sialic acid content of the red cell membrane. Polycythaemic erythrocytes have a higher electrophoretic mobility and higher sialic acid content than normals. Separation of the erythrocytes according to their densities shows that old polycythaemic erythrocytes have a higher electrophoretic mobility and sialic acid content than young normal ones. This suggests that the difference is not associated with a younger erythrocyte population in polycythaemia vera, but may represent a membrane change in the abnormal erythroid clone present in this disease.

Electrophoresis

Sedimentation and adhesion of platelets onto a horizontal glass surface.

An experimental method for measuring platelet adhesion to a glass surface and platelet sedimentation rate is described. Anticoagulated platelet-rich plasma is placed on a horizontal glass slide for various contact periods. The number of platelets adhering to the slide per unit area is recorded as a function of time. The experimental results are used to verify theoretical predictions which account for the effect of the slow sedimentation rate of the platelets and for their escape over the potential barrier between them and the solid surface. By a least-squares fit of the theoretical equation to the experimental data, both the platelet adhesiveness, in terms of P the probability to overcome the potential barrier, and the platelet sedimentation rate V are evaluated. A range of values of P and V for healthy humans is presented.

Blood Platelets

Physico-chemical explanation of blood cell adhesion in thrombus formation.

A model is suggested which assumes that the rate of deposition of cells is determined both by hydrodynamic factors and by Brownian motion over the potential barrier caused by London and double-layer forces in the immediate vicinity of the deposition surface. The height of the barrier in the potential energy of interaction between blood cells and various surfaces is analyzed in relation to the physical properties of the cells, surfaces, and solutions. Based on this analysis, the adhesion of platelets to injured blood vessel walls and to non-biologic materials, the lack of adhesion of red blood cells under the same conditions, the mechanism of ADP induced aggregation and the interaction with blood flow are explained. The qualitative predictions of the model are substantiated by available experimental information. Quantitative results are presented in terms of a time constant, which typifies a period of contact with a surface, during which appreciable deposition occurs.

Adenosine Diphosphate