Biomedical subjects
Publications and source records attributed to A J Marengo-Rowe.
A rapid and reproducible electrophoretic method for the separation and quantitation of haemoglobins on cellulose acetate is described. The accuracy of the method and its possible sources of error are discussed. The normal range for haemoglobin A(2) by this method is 1% to 3% of the total haemoglobin concentration. Blood samples from 32 thalassaemic patients showed haemoglobin A(2) values of 3.5% to 7%.
The present study defines excessive bleeding in patients who undergo cardiopulmonary bypass, and evaluates the use of coagulation testing to predict those patients that bleed excessively. Evaluation of 774 consecutive patients undergoing aortocoronary bypass surgery was carried out. Cardiopulmonary bypass consisted of a bloodless prime and a Harvey bubble oxygenator. In the postoperative period, excessive hemorrhage was defined as that exceeding 600 ml chest tube drainage in the first eight hours. One hundred and sixty-three patients (21%) were noted to be in this category. Excessive bleeding postoperatively was best predicted by a PTT greater than 45 seconds, a PT greater than 19 seconds, a fibrinogen level less than 225 mg/dl and a TFT equal to or less than 1:32. These laboratory findings occur singly or in combination. The assessment of platelet, numbers or function and fibrin(ogen) split products were of no prognostic value. Using these criteria, the re-exploration rate for excessive hemorrhage and/or tamponade was 0.6 per cent (5 out of 774 patients). No preoperative laboratory test of hemostatic function was useful in predicting coagulopathies resulting from cardiopulmonary bypass.
A photodynamic method has been evaluated as a means of eradicating viral contaminants with the potential for rendering blood safe for transfusion. Herpes simplex virus type 1 (HSV-1) was tested under flowing conditions in culture media or in blood supplemented with the virus. Hematoporphyrin derivative was used as the sensitizer and was photoactivated with visible light at 630 nm and 5 J/cm2. HSV-1 in suspension both in culture medium as well as in blood was shown to be killed. The human immunodeficiency virus was also found to be photoinactivated in flowing cell culture medium and, thus, potentially may be inactivated in blood. These findings extend our previous studies which demonstrated that enveloped viruses can be photoinactivated with hematoporphyrin derivative in a static fluid system. Analysis of blood cell number, red cell lysis, plasma proteins, and other standard hematological tests showed no significant change. The possibility that transfusion-associated acquired immunodeficiency syndrome (AIDS) may result from a blood unit infected with human immunodeficiency virus that tested negative makes it imperative that a safe and effective means of viral killing be developed. The system reported here offers promise as an effective approach to this problem.