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Biomedical subjects

R M Ibbotson

Publications and source records attributed to R M Ibbotson.

17 recordsLinked to original sources

Reduced quality of clot formation with gelatin-based plasma substitutes.

We have studied, over a wide range of dilutions using techniques of clot weight, thrombelastography and scanning electron microscopy, the physical properties of a blood clot formed in vitro when fresh blood was diluted with gelatin-based colloid solutions compared with crystalloid controls. The colloid solutions tested (3.5% polygeline (Haemaccel) and 4% succinylated gelatin (Gelofusine)) produced clots that had reduced median weight (P < 0.001 and P = 0.018, respectively) and reduced mean shear modulus (P < 0.001) compared with crystalloid controls. Scanning electron microscopy showed that the fibrin formed a less extensive mesh in the presence of the gelatin-based colloids compared with crystalloid. Reduction in clot quality with gelatin-based colloids has not been noted previously and further work is needed to ascertain if this occurs in vivo as these solutions are used frequently in patients who require full haemostatic competence.

Blood Cells↗

Effect of danazol on the biochemical abnormality of inherited antithrombin III deficiency.

Seven members of a family affected by hereditary antithrombin III deficiency were identified. The disorder was associated with recurrent spontaneous episodes of phlebitis, deep venous thrombosis, and pulmonary embolism in middle age. Danazol, a 17-alkyl derivative of ethinyl testosterone, which has been used to treat other antiprotease deficiency states, was assessed in the management of two men with antithrombin deficiency. In a dose of 600 mg a day danazol appeared to correct the antithrombin deficiency. This drug may provide a useful adjunct to anticoagulant treatment, particularly before surgery.

Adult↗

High mean platelet volume after myocardial infarction: is it due to consumption of small platelets?

Seventy nine men surviving after sustaining a myocardial infarction in 1982, and who had at that time had raised mean platelet volumes compared with controls, were followed up after 18 months. The shape of each man's platelet distribution curve was calculated from the mean platelet volume, platelet count, and platelet distribution width. The calculated curves were in close agreement with the curves plotted by the Coulter counter from the raw data. These curves did not differ significantly from those of a current control group, but the curves plotted from the variables measured at the time of myocardial infarction in 1982 showed a deficit of platelets in the volume range 5-12 fl amounting at maximum to 30% (p less than 0.0001); there were no significant differences above 12 fl. The deficit of small platelets became more appreciable during initial admission, was less at one month's follow up, and had disappeared at one year. The deficit of small platelets is probably an effect rather than a cause of infarction.

Blood Platelets↗

Platelet size in myocardial infarction.

The mean platelet volume and platelet count were measured serially in 100 patients soon after myocardial infarction and again at a follow up clinic about seven weeks later. The results were compared with those in age matched controls. The mean platelet volume after infarction (mean 9.07 fl (SE 0.08] was significantly greater than in the controls (8.32 fl (SE 0.07); p less than 0.001), and was still raised at the follow up clinic (8.69 fl (SE 0.10); p less than 0.01). The mean platelet count on admission (275 X 10(9)/1 (SE 7] was significantly lower than in the control group (295 X 10(9)/1 (SE 5); p less than 0.05) and fell significantly during admission, with a mean change of -36 X 10(9)/1 (95% confidence limits -26, -45; p less than 0.01). At the follow up clinic the platelet count had risen to a level not significantly different from the admission value. As larger platelets are haemostatically more active, the finding of an increased mean platelet volume after myocardial infarction provides further evidence that abnormal platelet behaviour may be implicated in the process of infarction.

Adult↗

Congenital dyserythropoietic anaemia with unusual cytoplasmic inclusions.

A case of congenital dyserythropoietic anaemia is described which appears to be at variance with the accepted classification. The morphological findings are of normoblastic hyperplasia with marked cytoplasmic vacuolation. Electron microscopy shows these to be myelin figures in all stages of erythroid differentiation.

Anemia↗

The simultaneous presentation of Hodgkin's disease of myeloma.

The simultaneous presentation of Hodgkin's disease and multiple myeloma is described. This is rare as only one previous case appears to have been documented. Speculations as to the aetiology are discussed as well as the significance of the presentation.

Hodgkin Disease↗

Failure of orally administered hydroxychloroquine sulphate to prevent venous thromboembolism following elective hip operations.

In a double-blind, randomized trial of orally administered hydroxychloroquine sulphate in the prevention of venous thromboembolism after elective surgery on the hip, the drug or a placebo was given to fifty consecutive patients. Therapy was commenced on the day before the operation and continued for fourteen days. The diagnosis of deep venous thrombosis was made by daily thermographic scanning of the legs and confirmed by phlebography. The diagnosis of pulmonary embolism was made by perfusion lung scanning. No significant difference in the incidence of thromboembolism was found between treated and control groups. The results provide evidence that substances which reduce the incidence of thromboembolism in general surgery may not be effective in operations on the hip.

Administration, Oral↗

Serum fibrin(ogen) degradation products in diagnosis of deep-vein thrombosis and pulmonary embolism after hip surgery.

Levels of fibrin(ogen) degradation products (F.D.P.) have been measured by radioimmunoassay for degradation product E (FgE) and by tanned-red-cell haemagglutination-inhibition immunoassay (T.R.C.H.I.I.) in the serum of thirty-three patients undergoing total hip replacement. Levels of F.D.P. did not correlate with thermographic evidence of deep-venous thrombosis. However, in 34 patients with pulmonary embolism, levels of F.D.P. measured by the T.R.C.H.I.I. were transiently raised at the time of embolus, and FgE concentrations were increased for up to 5 days preceding the embolus. Since the measurments of FgE is simple, convenient, and cheap, this estimation might constitute a valuable screening test for major thromboembolic episodes in the postoperative period.

Aged↗

The influence of paraproteinaemia on the technicon automated platelet counter.

In five patients whose serum contained a paraprotein it has been shown that platelet counts obtained using the Technicon AutoCounter are much too high. In two patients with IgG gammopathy the error is caused by some factor in the red cells lysed by the diluent solution 2M urea. In three patients with IgM gammopathy spurious platelet counts were produced by platelet-poor plasma when diluted with 2M urea. It is recommended that at the present time no patient known to have a paraprotein should have platelet counts performed on the AutoCounter.

Blood Cell Count↗