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Biomedical subjects

N J Griffiths

Publications and source records attributed to N J Griffiths.

8 recordsLinked to original sources
PubMed1979

The incidence of postoperative pulmonary perfusion defects.

The incidence of postoperative thromboembolism was studied using radioisotope lung perfusion and ventilation scanning. 26% of patients had defects on their pre-operative scans and 8% developed new unmatched perfusion defects postoperatively, indicating possible pulmonary emboli. This latter figure was much lower than some previously recorded results and was similar in 2 groups of patients--one receiving dextran 70 prophylaxis during operation and the other a control group who received saline.

Dextrans↗
PubMed1979

Factors affecting the fibrinolytic response to surgery.

The stress of injury and surgical operation results in an initial increase in the spontaneous fibrinolytic activity of the blood which is followed by a period of reduced activity in the postinjury or postoperative period. This 'fibrinolytic shutdown' is particularly marked in patients with malignant disease and occurs irrespective of whether or not they develop a deep venous thrombosis. It also occurs in patients with benign disease and in these patients is greater, though only on the first postoperative day, in those who develop deep venous thrombosis. Venous occlusion studies suggest that this reduction in spontaneous fibrinolytic activity may be the results of a reduction in the fibrinolytic capacity of the vascular endothelium resulting either from a deficiency of the enzyme plasminogen activator or an inability to release the enzyme from the endothelium. Changes in antiplasmins, the inhibitors of the fibrinolytic system, also occur as a result of the stress of operation. Plasma levels of alpha2-macroglobulin fall while those of alpha1-antitrypsin rise. These changes occur irrespective of the presence of malignant or benign disease and do not appear to influence the development of deep venous thrombosis.

Endothelium↗
PubMed1977

Alteration in fibrinolytic capacity after operation.

The fibrinolytic response to 20 min of forearm venous occlusion was studied in patients undergoing major and minor operations. Fibrinolytic capacity, which is defined as the increase in fibrinolytic activity resulting from a period of venous occlusion, was significantly reduced on the first postoperative day after major operations, but not after minor operations. Since venous occlusion results in the release of plasminogen activator from the vascular endothelium into the blood, these findings suggest that the reduction in the level of spontaneous fibrinolytic activity after major operations is the result either of exhaustion of the vascular endothelium of plasminogen activator or defective synthesis and release of this enzyme from the endothelium.

Adult↗
PubMed1977

Plasma fibrinolytic inhibitors after operation.

The response of the fibrinolytic system to the stress of a surgical operation has been studied in a group of 39 patients. Fibrinolytic activity was stimulated during the operation but depressed during the early postoperative period. This was accompanied by an increase in the level of fibrinolytic inhibitors in the plasma after operation. This increase in fibrinolytic inhibitors was a result of a significant rise in alpha1 antitrypsin; the level of alpha2 macroglobulin fell both during and after the operation.

Adolescent↗
PubMed1976

Changes in the fine structure of venous endothelium in the rabbit following adrenaline infusion.

The fine structure of the endothelium lining the femoral and mesenteric veins in the rabbit was examined following the infusion of concentrations of adrenaline varying from 0.5 to 5.0 mug/kg. Control animals were infused with saline. Vesiculation of the endothelial cells was observed following each infusion of adrenaline, the effect being most marked with the highest dose used. It is suggested that this vesiculation may be associated with the release of antihaemophilic globulin and/or plasminogen activator from the endothelial cells.

Animals↗