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Biomedical subjects

D K Cooper

Publications and source records attributed to D K Cooper.

At least 307 records · Page 17Linked to original sources
PubMed1969

Agricultural accidents: a study of 132 patients seen at Addenbrooke's Hospital, Cambridge, in 12 months.

In a 12-month study 132 patients injured in agricultural accidents were treated at the Accident Service of Addenbrooke's Hospital, Cambridge. Agricultural machinery and implements were concerned in 50% of the accidents and animals in 10%. The state of immunity against tetanus of these patients was found to be extremely low, only 9% being fully immunized, and 56% having never received a course of prophylactic adsorbed tetanus toxoid.While prevention is obviously the only real solution to accidents of any nature, legislation is not enough to achieve this, and the final responsibility lies with the farmworker to ensure that all safety precautions are followed.

Accident Prevention↗
PubMedDate not supplied

Xenoantigens and xenoantibodies: their modification.

The hyperacute rejection of pig organs by primates, including humans, results from antibody-mediated complement activation. Protection from complement injury still leads to delayed rejection, which results from other mechanisms that may also be dependent on the presence of antibody. Anti-pig antibodies are directed largely, if not entirely, against alpha-galactose (alpha Gal) epitopes on pig vascular endothelium. Prevention of antibody-antigen binding is being attempted by methods that (1) alter antigen expression on the donor organ or (2) deplete the potential recipient of anti-alpha Gal antibody. To date, most progress has been made in depleting antibody by extracorporeal immunoadsorption using immunoaffinity columns of synthetic alpha Gal oligosaccharides. A pig organ transplanted into a recipient baboon depleted of antibody functions for several days--in contrast to minutes to hours in unmodified baboons. The return of antibody, however, results in rejection of the graft. Pharmacologic immunosuppressive agents are relatively ineffective for prolonged suppression of anti-alpha Gal production. Total-body irradiation and splenectomy are proving more successful. Studies are continuing with the aim of achieving a state of B cell tolerance toward alpha Gal epitopes.

Animals↗
PubMedDate not supplied

The pig as a source of cardiac xenografts.

The inadequate availability of human donor hearts and other organs has inspired interest in the field of xenotransplantation. Historically, ten attempts to transplant animal hearts into human recipients have been reported. Those who received hearts from nonhuman primates (i.e., baboons and chimpanzees) survived rather longer than did those who received hearts from nonprimates (i.e., sheep and pigs). Nevertheless, current opinion is that the pig is the best candidate as a source of hearts for humans despite the considerable immunologic disparity between the two species. Pigs are available in large numbers and can be bred easily and rapidly. They grow to appropriate sizes and their cardiovascular system is similar to that of humans. Substantial knowledge has been accumulated regarding both genetic engineering and tolerance induction in pigs, two strategies that may help to overcome the existing immunologic barriers. Concern has been raised, however, with regard to the potential for the transfer of a porcine infection with the pig organ to the human recipient. This brief review addresses these and other aspects of the use of the pig as a source of hearts for patients with end-stage cardiac disease.

ABO Blood-Group System↗
PubMedDate not supplied

Prevention of loss of vertebral bone density in heart transplant patients.

Seventy-six patients (63 men, 13 women) have been followed up by vertebral bone density (VBD) studies from 3 to 36 months. VBD was measured by single-energy computerized tomographic scan. Before transplantation, VBD was found to be lower than in age-matched controls (less than 40 years of age [group 1], 96% of controls: 40 through 49 years of age [group 2], 77%; 50 to 60 years of age [group 3], 87%; more than 60 years of age [group 4], 76%). After transplantation, despite oral calcium supplements, VBD fell further in all but two patients (97%), which was almost certainly related to maintenance steroid and cyclosporine therapy, and was most marked in the older groups (group 2, 67% compared with age-matched controls at 6 months; group 3, 60%; group 4, 50%). Intensive therapy with synthetic salmon calcitonin (in 29 of 76 patients [38%]), testosterone (in 33 of 63 men [52%]), or estrogen (in 12 of 13 women [92%]) limited, but did not totally prevent, further loss in VBD; in patients who had shown an approximate 45% loss of VBD from pretransplantation levels, further loss was reduced to between 4% and 10%. Five patients increased bone density after calcitonin therapy. Despite significantly reduced VBD in several older patients, minor vertebral bone compression developed in only one patient. We recommend that all patients undergoing heart transplantation, particularly those over the age of 50 years, should be followed by VBD studies, and therapy should be administered to prevent VBD loss.

Adult↗
PubMedDate not supplied

Donor-heart evaluation by monitoring the left ventricular pressure-volume relationship: clinical observations.

Fourteen donor hearts were assessed by measurement of dopamine requirement, basic hemodynamic parameters (for example, systolic blood pressure), and the left ventricular pressure-volume relationship. The latter function was measured by a combination microtipped manometer/conductance catheter placed in the left ventricle through the ascending aorta. With an isoproterenol dose 24 hours after transplantation as the measure of cardiac performance, multiple linear regression analysis indicated that the ratio of arterial elastance (Ea) to left ventricular end-systolic elastance (Ees), ventriculoarterial coupling (Ea/Ees), and myocardial ischemic time were good predictors of posttransplantation cardiac performance. Dopamine requirement and basic hemodynamic data were not. Twelve implanted hearts showed an Ea/Ees of less than 1.0 and showed good early (less than 24 hours) and late function. Two hearts considered on clinical grounds to be unsuitable for transplantation showed an Ea/Ees of more than 1.0. The data suggest that measurement of the left ventricular pressure-volume relationship would appear to be a clinically useful predictor of donor-heart performance after transplantation.

Adult↗