Charles D Forbes

Biomaterials for blood-contacting applications

Consideration of biomaterials for blood-contacting applications should take into account blood-biomaterial interactions, factors influencing the blood response and evaluation procedures. Examination of blood-biomaterial interactions indicates that relevant features are protein adsorption, platelet reactions, intrinsic coagulation, fibrinolytic activity, erythrocytes, leucocytes and complement activation. Factors influencing the blood response to a biomaterial in clinical application are the biomaterial structure, the presence of an antithrombotic agent, the patient status as determined by the disease and drug therapy, and the nature of the application. Evaluation options for biomaterials are clinical, in vivo, ex vivo and in vitro, with ex vivo and in vitro procedures relevant for biomaterial development.

Free radical pathology in chronic arterial disease

The generation of toxic oxygen metabolites is more usually associated with inflammation. However, pathological free radical reactions can cause tissue damage by adversely affecting prostacyclin (PGI2) synthesis allowing initiation of coagulation. We have assessed changes in the red cell defence to toxic oxygen metabolite generation, viz measurement of glutathione concentration (GSH) and superoxide dismutase activity (SOD). GSH and SOD were measured in 20 patients with peripheral arterial disease, 22 patients with vasculitis, and 11 patients with angina, and compared to 17 matched controls. The 53 subjects with arterial disease had significantly lower SOD levels: in contrast GSH levels were significantly higher. Extracellularly plasma thiol levels (PSH) were low and caeruloplasmin (Cp) levels were high. We suggest that free radical pathology exists not only in inflammatory vascular disease but also in atherosclerosis.

Daily living problems of people with haemophilia and HIV infection: implications for counselling.

The advent of AIDS not only signifies the emergence of a new disease that affects hitherto healthy members of the general population but also highlights many unresolved problems of people with haemophilia, a life-long genetic disorder of blood clotting. Although HIV infection and the threat of AIDS has been a tragedy for people with haemophilia, the reported study shows that in spite of recent technological advancement in treatment, problems caused by haemophilia as such are still devastating for some severely affected patients. The ability of people with haemophilia to cope with their daily living problems such as chronic and acute pain, stress in the family, difficulties with unemployment and social relationships affects their response to HIV/AIDS. These facts have important implications for their rehabilitation and counselling and raise questions about coping with HIV/AIDS for other risk groups.

Knowledge of hiviaids and behavioural change of people with haemophilia

Abstract People with haemophilia have been infected by HIV through blood products required for the treatment of their bleeds. In a recent study in Scotland their knowledge of HIV/AIDS and their behavioural changes were explored. It was found that people with severe haemophilia were better informed about HIV and AIDS than the mildly/moderately affected, bur only the knowledge of precautions in mildly/moderately affected patients was positively associated with their change of sexual practices. Mildly/moderately affected patients, who were less at risk of contracting HIV, reduced their treatment more than the severely affected patients. Only one third of patients applied safe-sex practices and a greater proportion of those who did not were single men, some of them HIV antibody positive.