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Biomedical subjects

M W Rampling

Publications and source records attributed to M W Rampling.

At least 37 records · Page 2Linked to original sources
PubMed1988

Diabetic hypertension--the importance of fibrinogen and blood viscosity.

Fibrinogen and blood viscosity were measured in 72 stable non-insulin dependent diabetic subjects, 31 without hypertension, and 41 who had treated hypertension. The hypertensive group had higher plasma fibrinogen levels and blood viscosity. As both these rheological variables have been associated with micro- and macro-vascular disease, these findings may provide a possible explanation for the mechanism of the increased vascular disease seen in hypertensive compared with normotensive diabetic subjects.

Blood Viscosity↗
PubMed1986

A comparison of five methods for estimating red cell aggregation.

A comparison has been made of the responses of five techniques for estimating the degree of aggregation in red cell suspensions. They were the use of direct microscopic observation, the erythrocyte sedimentation rate test, low shear rate viscometry, the Myrenne Erythrocyte Aggregometer and the Paar Oscillating Capillary Rheometer. The test samples consisted of normal red cells suspended in buffer to which fibrinogen was added as an aggregating agent. Each test exhibited a fibrinogen threshold concentration before any response occurred. The range of response and sensitivity was highest for the sedimentation test, viscometry and the Paar device. However the simplicity and rapidity of operation of the Myrenne machine make it attractive in a clinical setting. Finally, inspite of its relative insensitivity, the microscopic technique has the great advantage of being the only one that produces unequivocal data since it is based on direct observation.

Blood Sedimentation↗
PubMed1986

A study of the haematological and haemorheological consequences of venesection.

A study has been made of a number of haematological and haemorheological factors following venesection therapy. Haematocrit was very effectively reduced by the venesection regimen and led to a fall in whole blood viscosity in spite of the microcytosis that was eventually induced in all the subjects. No clinically significant coagulation changes were observed. It is concluded that a simple venesection regimen without volume replacement is a safe procedure for improving blood rheology.

Aged↗
PubMed1983

A theoretical analysis of the effects of varying fibrinogen concentration and haematocrit on the flow characteristics of blood in cylindrical tubes.

The viscosity: shear rate relationship of whole blood is shown to be described to a good approximation by a bi-linear plot on log: log axes. This has allowed an analytical solution to be obtained which gives a full description of the flow properties of blood in rigid tubes of a size where the Fahraeus-Lindqvist effect is minimal. As a result the profound effects that changing haematocrit has on blood flow in such tubes can be quantitated. The analysis also shows that in similar circumstances altering fibrinogen concentration is of rheological significance only at flow rates below the normal physiological range.

Blood Flow Velocity↗
PubMed1981

The binding of fibrinogen and fibrinogen degradation products to the erythrocyte membrane and its relationship to haemorheology.

A study has been made of the binding of fibrinogen to erythrocyte membranes. The amount of fibrinogen bound is found to be proportional to the concentration in the suspending phase (up to 10 g/l) and to be unaffected by other plasma proteins or calcium ions (up to normal concentrations). The binding is also unaffected by temperature (between 4 and 37 degrees C). However it is sensitive to both pH and ionic strength variation. A similar study of the major fibrinogen degradation products (FDP) produced by plasmin shows that these all bind to red cell membranes but by different amounts. A model based on these data is suggested for the positions of the binding regions on the fibrinogen and FDP molecules and is used to explain their influence on rouleaux formation and on the flexibility of the erythrocyte.

Anticoagulants↗
PubMed1976

A comparison of the sulphite and thrombin methods for measuring fibrinogen concentration of plasma from patients undergoing thrombolytic therapy.

A thrombin method for the determination of fibrinogen concentration has been compared with a non-enzymatic sulphite precipitation method on plasma from patients undergoing thrombolytic therapy with an intermittent plasminogen/streptokinase regime. There was very good agreement between the methods even when the determinations were made in the presence of high levels of fibrinogen degradation products (FDP), provided that the thrombin clottable fibrinogen was greater than 1 mg/ml. However, after extensive fibrinogen depletion, when the thrombin method underestimates fibrinogen concentration due to significant clot inhibition by FDP, an overestimate due to co-precipitation of fragments X and Y will be obtained by the sulphite method. This suggests that the simultaneous application of both techniques may provide a simple method of assessing the presence of high levels of anticoagulant FDP in various clinical disorders.

Evaluation Studies as Topic↗
PubMed1976

The sulphite precipitation method for fibrinogen measurement; its use on small samples in the presence of fibrinogen degradation products.

A technique based on precipitation by sodium sulphite (Na2SO3) has been developed for measuring the fibrinogen concentration of small (100 mul) samples. This technique offers technical advantages over the thrombin-clotting method, especially when measuring dilute solutions. Measurements made with the sulphite technique on fibrinogen solutions on plasma samples were not significantly different from those obtained with the thrombin-clotting method.

Fibrin Fibrinogen Degradation Products↗