Patient-oriented research facilitated through the establishment of the Nurses Network for Cooley's Anemia (CANNA).
Explore the source record for details and available documents.
Adult↗
Biomedical subjects
S M Carson
Publications and source records attributed to S M Carson.
Optimal flow rates for integrated cardioplegia.
BACKGROUND: Antegrade cardioplegic delivery may be impaired by coronary occlusions, whereas retrograde delivery of cardioplegic solution may be inhomogeneous, leading to an accumulation of lactate and hydrogen ions, the products of anaerobic metabolism. Integrated cardioplegia using continuous retrograde cardioplegia and antegrade infusions into completed vein grafts washes out metabolites accumulated in regions inadequately perfused by retrograde cardioplegia alone. To determine the flow rates required to achieve the greatest washout, we compared a high flow rate (200 ml/min) to a low flow rate (100 ml/min). METHODS: Twenty patients scheduled for isolated coronary bypass surgery were prospectively randomized to compare two flow rates for integrated cardioplegic protection using tepid (29 degrees C) blood cardioplegia. Arterial and coronary sinus blood samples were collected to evaluate myocardial metabolism. After antegrade arrest, cardioplegic solution was delivered by coronary sinus perfusion and simultaneous infusions into each completed vein graft at either high or low flow. RESULTS: Increasing from low to high flow increased the washout of lactate and hydrogen ions during the aortic crossclamp period. Two hours after crossclamp removal, ventricular function was better in the high flow groups. CONCLUSIONS: Tepid retrograde cardioplegia resulted in an accumulation of toxic metabolites. The addition of antegrade vein graft infusions at a flow rate of 100 ml/min resulted in a washout of these metabolites. A flow rate of 200 ml/min further improved this washout and resulted in improved ventricular function. An integrated approach to myocardial protection using a flow rate of 200 ml/min may improve the results of coronary bypass surgery.
Blood↗
Does the internal thoracic artery graft delay the recovery of myocardial metabolism?
BACKGROUND: The left internal thoracic artery (LITA) bypass graft to the left anterior descending artery has greater long-term patency than a saphenous vein graft. However, surgeons may be reluctant to use the LITA graft in some patients because they are unable to deliver cardioplegia to the left anterior descending artery territory. METHODS: We compared the myocardial levels of high-energy phosphates and their metabolites in patients who received an LITA graft with those in patients who received a saphenous vein graft to the left anterior descending artery territory during elective coronary artery bypass grafting. Right and left ventricular biopsy specimens were obtained at three times: before aortic cross-clamping, after cross-clamp removal, and after 10 minutes of reperfusion. RESULTS: No differences were found between the LITA graft group and the saphenous vein graft group in any right ventricular metabolites. There was an improvement in myocardial protection over time and a higher proportion of LITA graft patients in the late time period (early group, 63% versus late group, 80%; p < 0.01). Within each time period, there were no differences between the LITA and saphenous vein graft groups. Among patients receiving cold antegrade cardioplegia, the myocardial levels of high-energy phosphates were better preserved in those receiving an LITA graft. CONCLUSIONS: Advances in myocardial protection have led to improved preservation of high-energy phosphate levels after cardioplegic arrest. In patients undergoing elective coronary artery bypass grafting, the use of an LITA graft does not adversely affect myocardial metabolism. Further investigations are required to determine the effects of the use of the LITA during urgent or emergent procedures.
Adenine Nucleotides↗
Tepid antegrade and retrograde cardioplegia.
To determine the optimal temperature for the combination of antegrade and retrograde cardioplegia, 42 patients undergoing coronary artery bypass grafting were randomized to receive cold (9 degrees C; n = 14), tepid (29 degrees C; n = 14), or warm (37 degrees C; n = 14) blood cardioplegia delivered continuously retrograde and intermittently antegrade. Myocardial oxygen utilization, lactate and acid metabolism, and coronary vascular resistance were measured during the operation and cardiac function was assessed postoperatively. Myocardial oxygen consumption, lactate release and acid release were greatest with warm, intermediate with tepid, and least with cold cardioplegia (p = 0.0001). However, washout of lactate and acid at the time of cross-clamp release was reduced (p = 0.022) with tepid or cold compared with warm cardioplegia. Early postoperative left ventricular function was best preserved (p = 0.01) after tepid than after cold or warm combination cardioplegia. These results suggest that tepid combination cardioplegia reduced metabolic demands but permitted immediate recovery of cardiac function. This technique may provide better myocardial protection than cold or warm combination cardioplegia.
Aged↗
The optimal cardioplegic temperature.
Seventy-two patients undergoing coronary artery bypass grafting were randomized to receive cold (8 degrees C) antegrade or retrograde, tepid (29 degrees C) antegrade or retrograde, or warm (37 degrees C) antegrade or retrograde blood cardioplegia (n = 12 in each group). Myocardial oxygen utilization as well as lactate and acid metabolism were assessed intraoperatively and cardiac function was assessed postoperatively. Myocardial oxygen consumption and anaerobic lactate release were greatest during warm, intermediate during tepid, and least during cold cardioplegic arrest. Myocardial oxygen consumption and lactate release were underestimated during retrograde cardioplegia because of contamination of aortic root samples. Warm retrograde and tepid retrograde cardioplegia resulted in greater lactate and acid washout with reperfusion. Left ventricular stroke work indices were greater after warm antegrade and tepid antegrade cardioplegia than after cold antegrade cardioplegia, and right ventricular stroke work indices were greatest after warm antegrade cardioplegia. Warm antegrade cardioplegia increased aerobic metabolism during and after cardioplegia and preserved left and right ventricular function. Tepid antegrade cardioplegia reduced anaerobic lactate and acid release during arrest and preserved cardiac function.
Adult↗
Monoclonal antibodies against bovine tissue factor, which block interaction with factor VIIa.
Two monoclonal antibodies that recognize bovine tissue factor (coagulation factor III) have been obtained following the fusion of hyperimmune mouse spleen cells with NS-1 plasmacytoma cells. Both antibodies, TF1-E2 and TF1-F7, have gamma 1 heavy chains and lambda light chains. TF1-E2 and TF1-F7 have each been used to purify bovine tissue factor from a crude detergent extract of bovine brain by immunoaffinity chromatography. Both antibodies inhibit tissue factor procoagulant activity and block the association of factor VIIa with tissue factor. The association of TF1-F7 and tissue factor solubilized in Triton X-100 was measured under equilibrium conditions. The Kd for this antibody-antigen interaction was 2.1 +/- 0.2 nmol/L. TF1-E2 effectively competes with TF1-F7 for tissue factor binding, indicating that the monoclonal antibodies recognize overlapping sites on the protein. These antibodies will be useful reagents for large-scale purification and for structure-function studies of bovine tissue factor. In particular, since they appear to bind to the same region of the tissue factor molecule as factor VIIa, they will be useful as specific probes for studying the kinetics of tissue factor-initiated coagulation and for immunocytochemical localization of tissue factor in bovine cells.
Animals↗
Monoclonal antibody recognizing rabbit IgG (Fab). A specific reagent for second antibody applications.
A monoclonal mouse antibody, which recognizes a determinant on the Fab portion of rabbit IgG, has been obtained following fusion of hyperimmune mouse spleen cells with NS-1 plasmacytoma cells. The monoclonal antibody, RIg9C, has a gamma 1 heavy chain and a kappa light chain. RIg9C binds rabbit IgG but not human or bovine IgG. It has been conjugated with horseradish peroxidase for application in an enzyme-linked immunosorbent assay as well as for detection of antigens transferred from polyacrylamide gels to nitrocellulose. In enzyme-linked immunosorbent assays, the RIg9C-peroxidase conjugate was useful for measuring rabbit immunoglobulin either free in solution or in immune complexes. Using the enzyme-linked immunosorbent assay to quantitate antibody-antigen binding, the apparent dissociation constant was found to be 4 X 10(-8) M. Because of its low dissociation constant and specificity, RIg9C will be preferred over other reagents (e.g. second antibody and protein A) where sensitive recognition of only the Fab segment is critical.
Animals↗