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Biomedical subjects

D H Bevan

Publications and source records attributed to D H Bevan.

At least 37 records · Page 2Linked to original sources
PubMed1996

A prospective randomised controlled trial of postoperative autotransfusion with and without a heparin-bonded circuit.

Autotransfusion has been included in the routine protocol in some units as an effort towards blood conservation. In this study we aimed to measure the efficacy and limitations of autotransfusion and whether a heparin-bonded circuit had any advantage. One hundred five patients were randomised to one of three post-operative treatments. Group 1 (n = 34) was not autotransfused whereas groups 2 (n = 36) and 3 (n = 35) received autotransfusion with the circuit of group 3 coated with heparin. Homologous blood and blood products were given according to strict protocols identical for all groups. Transfused and circulating blood was analysed for haemostatic variables and the requirement for homologous blood was recorded. Autotransfused blood contained no intact platelets and very high levels of D-Dimers (a peptide fragment released when fibrin is lysed) which resulted in high levels of systemic D-Dimers in patients receiving autotransfusion. Flow cytometric analysis revealed that whilst platelet glycoprotein 1 b receptors were severely reduced immediately following surgery, there was no additional damage caused by autotransfusion. Furthermore, there was no difference in platelet aggregation, von Willebrand factor (vWF) multimetric analysis or clotting profiles between the groups. Median (interquartile range) blood loss was 898 ml (638-1195) in group 1, 853 ml (595-1348) in group 2 and 770 ml (615-1000) in group 3 (Kruskal-Wallis P = 0.46). Median transfusion requirements were 2 units in each group. Whilst auto-transfusion does not appear to compromise haemostasis, it does not reduce the requirement for homologous blood and heparin-bonding of the circuit has no impact.

Aged↗
PubMed1995

Sickle cell anemia, right atrial thrombosis, and the antiphospholipid antibody.

We report a patient with sickle cell anemia (homozygous Hb SS) and typical features of sickle chest syndrome but with no response to exchange transfusion. A right atrial thrombus was found, and antiphospholipid antibodies were detected in his blood. He responded to thrombolytic therapy. The relationship between right atrial thrombus and massive pulmonary embolus, and the implications of an additional thrombophilic state in sickle cell disease are discussed.

Adult↗
PubMed1995

Primary non-Hodgkin's lymphoma of the thyroid with bone marrow infiltration at presentation.

Primary non-Hodgkin's lymphoma of the thyroid is predominantly a disorder of elderly females. Most patients present with limited disease and receive local irradiation. Presentation with advanced disease is uncommon and, consequently, bone marrow examination is not always done. We report a patient with primary thyroid lymphoma who had bone marrow infiltration at presentation and discuss the importance of this investigation in management.

Aged↗
PubMed1995

Erythrocyte aplasia and systemic lupus erythematosus.

Pure erythrocyte aplasia is a recognised feature of systemic lupus erythematosus (SLE); here we report two cases, one predating the onset of SLE, the other following a long period of disease quiescence. One case demonstrates the typical features of this disorder and was successfully treated with prednisolone. The second case is unusual in being resistant to immunosuppressive treatment. Bone marrow culture from the second patient revealed an inhibition of BFU-E colony formation in the presence of the patient's serum, indicating that a serum inhibitor of haemopoiesis was present. Furthermore, following T cell depletion of this patient's marrow, there was an increase in BFU-E, CFU-G and CFU-GM colony growth implicating, in addition, a possible T cell-mediated inhibition of marrow haemopoiesis. This is a novel observation and may explain the resistance shown by this patient to standard treatment.

Adult↗
PubMed1994

Eosinophilic folliculitis occurring after bone marrow autograft in a patient with non-Hodgkin's lymphoma.

Eosinophilic pustular folliculitis is a rare disorder previously reported predominantly in Japanese people who are otherwise healthy. Recently, the disorder has been noted in patients with acquired immune deficiency syndrome, as has eosinophilic folliculitis, a similar but distinct entity. The authors report a patient with eosinophilic folliculitis who was immunocompromised after high dose chemotherapy and bone marrow autograft for treatment of non-Hodgkin's lymphoma.

Adult↗
PubMed1994

Hypercoagulable states in patients with leg ischaemia.

Hypercoagulable states are found in up to 10 per cent of patients with a history of unexplained venous thrombosis. To investigate the prevalence in arterial thrombosis, thrombophilia screening was performed on 124 patients who had previously undergone lower-limb revascularization, 45 claudicants and 27 controls. Of the patients who had undergone revascularization 40 per cent had a hypercoagulation abnormality (low levels of protein C, protein S and antithrombin III or presence of the lupus anticoagulant) in comparison with 27 per cent of claudicants and 11 per cent of controls (P < 0.01). Furthermore, patients who had suffered reocclusion after revascularization were significantly more likely to have a hypercoagulation abnormality than those who had not (P < 0.05), even if the occlusion had occurred more than 6 months previously. Lupus anticoagulant was the abnormality most frequently detected and, like low protein C levels, was found only in patients with peripheral vascular disease. It appears that hypercoagulable states are common in patients with arterial disease and may predispose to failure of revascularization.

Aged↗
PubMed1994

Pre-operative aspirin decreases platelet aggregation and increases post-operative blood loss--a prospective, randomised, placebo controlled, double-blind clinical trial in 100 patients with chronic stable angina.

Aspirin has an established benefit in reducing the incidence of coronary events and vein graft occlusion. We have now assessed the risk of pre-operative aspirin in a prospective, randomised, double-blind clinical trial in 100 patients scheduled for elective coronary artery surgery. Any prescribed aspirin and non-steroidal anti-inflammatory drugs were discontinued 2 weeks pre-operatively and these were replaced by a randomly assigned tablet of either aspirin 300 mg daily or placebo taken until the day of surgery. Patient compliance was confirmed by serum and urinary salicylate analysis. The two groups were similar in demographic characteristics, bypass time, number of grafts placed and number of internal mammary arteries used. All patients survived to be discharged home (see Table). Aspirin decreases platelet aggregation to arachidonic acid and to collagen both pre- and post-operatively. The benefit of pre-operative aspirin has to be balanced against the risk of increasing post-operative blood loss, re-exploration for excessive bleeding and transfusion requirements.

Aspirin↗
PubMed1994

The radiological features of adult T-cell leukaemia/lymphoma.

Adult T-cell leukaemia/lymphoma (ATLL) results from a monoclonal expansion of T-cells infected with the human T-cell lymphotropic virus type 1 (HTLV-1). Six cases of ATLL, three males and three females all from the Caribbean and with a mean age of 55 years, have been reviewed retrospectively, illustrating the wide spectrum of radiological changes. One patient had extensive mediastinal adenopathy, hitherto an unrecorded finding in ATLL.

Female↗
PubMed1994

Aprotinin inhibits fibrinolysis, improves platelet adhesion and reduces blood loss. Results of a double-blind randomized clinical trial.

The present recommendation is that aprotinin should be started before cardiac surgery, but as bleeding is only a problem in a minority, most patients are treated unnecessarily. In a prospective, randomised, double-blind trial we have studied the use of aprotinin, given only to the minority of patients who bled significantly post-operatively and who had not received prophylactic aprotinin. Sixty patients, who bled in excess of 400 ml in the first 3 h post-operatively were randomised to receive either aprotinin (2 x 10(6) KIU loading dose followed by an infusion of 0.5 x 10(6) KIU/h for 4 h) or placebo, in addition to conventional treatment. The demographic characteristics and the surgical procedures performed were similar in the two groups. Haematological variables were measured (A) before and (B) at the end of the infusion. Three patients were re-explored for excessive bleeding in each group and one patient died in each group. The patients in the aprotinin group bled significantly less and had higher haemoglobin levels on discharge than the patients in the placebo group. The tissue plasminogen activator antigen decreased and the fibrinogen level increased in the aprotinin group. In addition, aprotinin increased the number of surface GPIb platelet receptors as estimated by flow cytometry (36% versus 5%, P < 0.01) and maintained the platelet von Willebrand Factor activity (vWF). There was no significant difference in D-dimers, fibrin(ogen) degradation products, plasma vWF activity and antigen, platelet vWF antigen, platelet aggregation (to collagen, arachidonic acid, platelet activating factor and ristocetin), platelet count or transfusion of blood products between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Splenic sepsis in sickle cell disease.

We describe two patients with sickle cell disease (SCD) who developed infections situated in the spleen. One patient had a splenic abscess and there was strong clinical evidence for an infected splenic infarct in the second patient. SCD predisposes to splenic infection because of functional hyposplenism, defective phagocyte function and splenic infarction. Splenic infections can occur in patients who might be considered to have an absent spleen and the diagnosis of splenic abscess should be considered in individuals with SCD who present with fever and abdominal pain.

Abscess↗
PubMed1992

Splenic lymphoma with villous lymphocytes in tropical West Africa.

Splenic lymphoma with villous lymphocytes (SLVL) is a monoclonal B-lymphoproliferative disorder characterised by splenomegaly and distinctive villous lymphocytes in the peripheral blood. It has not previously been reported from Africa, but we describe ten Ghanaian patients with SLVL seen at one hospital during a 4-year period. The clinical presentation is similar in Africa and in temperate regions, though the lymphocyte count is higher in African patients and the disorder predominantly affects middle-aged women rather than elderly men. It is likely that SLVL has previously been classified as splenic chronic lymphocytic leukaemia or hyper-reactive malarial splenomegaly.

Adult↗
PubMed1992

Coagulation-factor deficiencies and abnormal bleeding in Noonan's syndrome.

Noonan's syndrome is characterised by a dysmorphic facies, congenital heart disease, and short stature, and is inherited as an autosomal dominant trait. Because abnormal bleeding has also been reported, we investigated a group of patients for coagulation-factor deficits. Of the 72 individuals studied (37 male, 35 female, mean age 11.4 years), 47 (65%) had a history of abnormal bruising or bleeding. 29 patients (40%) had a prolonged activated partial thromboplastin time. Specific abnormalities in the intrinsic pathway of coagulation (partial factor XI:C, XII:C, and VIII:C deficiencies) were found in 36 patients (50%). Multiple abnormalities among these 36 patients included combined factor XI:C and XII:C deficiencies (4 patients) and factor XI:C and VIII:C deficiencies (4), and 1 patient had combined factor VIII:C, XI:C, and XII:C deficiency. There was poor correlation between a history of abnormal bleeding and coagulation-factor deficit. In five families, similar coagulation-factor deficiencies were present in first-degree relatives with the syndrome. The pattern of inherited bleeding abnormalities seen in Noonan's syndrome suggests autosomal regulation of the intrinsic coagulation pathway.

Adolescent↗
PubMed1991

Use of immunoglobulin gene rearrangements to show clonal lymphoproliferation in hyper-reactive malarial splenomegaly.

In Africa, hyper-reactive malarial splenomegaly (HMS), which is also known as tropical splenomegaly syndrome, can be associated with a prominent lymphocytosis in blood and bone marrow that is difficult to distinguish clinically from chronic lymphocytic leukaemia (CLL). The observation that some patients with HMS become resistant to treatment with anti-malarial drugs has led to the suggestion that HMS may evolve into a malignant lymphoproliferative disorder. To test this hypothesis, 22 Ghanaian patients with HMS and/or lymphocytosis were categorised by degree of response to proguanil according to standard clinical criteria, and DNA was extracted from peripheral blood cells and screened for rearrangements of the Jh region of the immunoglobulin gene with a DNA probe. Clonal rearrangements of the Jh region were found in all 3 patients with no response, in none of 13 patients with sustained response, and in 2 of 6 patients with moderate response or relapse on proguanil therapy. The detection of such rearrangements, and hence clonal lymphoproliferation in individuals with clinical features intermediate between HMS and CLL, supports the hypothesis that HMS may evolve into a malignant lymphoproliferative disorder.

Adolescent↗
PubMed1991

Abnormal neutrophil adhesion in sickle cell anaemia and crisis: relationship to blood rheology.

Defects in neutrophil adhesion and migration may contribute to the susceptibility to infection seen in sickle cell anaemia (SCA). These dynamic defects may be influenced by abnormalities in blood rheology found in this disorder. A whole blood model was used to study neutrophil adhesion in SCA patients: neutrophil adhesion to protein coated glass was quantitated by measuring the rate of disappearance of neutrophils from heparinized whole blood circulating through a perfusion chamber. Twenty-three adult patients (Hb SS) were studied in asymptomatic steady state, of whom nine were also studied during pain crisis, both before and 4-7 d after conventional therapy. Red cell and granulocyte filterability and whole blood and plasma viscosity were also measured. The half-time for disappearance from the perfusion system (t1/2) of neutrophils from patients in the steady-state was 93.5 +/- 8.4 min, compared to 49.1 +/- 2.8 min in normal age-matched controls (P = 0.001). In crisis t1/2 was further prolonged to 170.0 +/- 16.1 min (P = 0.01 v. steady state). After therapy, t1/2 decreased to 57.0 +/- 4.5 min (P = 0.001 v. pre-therapy state and P = 0.009 v. steady state) and was comparable to Hb AA controls. These findings reveal a neutrophil adhesion defect in SCA which worsens in crisis but is corrected following supportive therapy. Red cell filterability (expressed as average resistance to flow and pore-clogging particles) and white cell filterability (expressed as pore-clogging particles) were also abnormal in SCA and were found to correlate with neutrophil adhesion. Plasma viscosity also correlated with adhesion t1/2. The defect appears to be related to abnormal blood flow properties in SCA but the rheological factors cannot fully explain either the steady-state defect or the marked changes in neutrophil adhesion during crisis.

Adult↗