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Biomedical subjects

A S Daar

Publications and source records attributed to A S Daar.

At least 55 records · Page 3Linked to original sources

Culture and psychology in organ transplantation.

The cultural and psychological dimensions of organ transplantation are often overlooked in the process of meeting its exacting technical requirements. This new branch of medicine has brought with it new ways of understanding death, human rights, commerce, gift giving, and ethics. It produces strong emotions in recipients, donors and transplanters alike. These factors need to be taken fully into consideration if organ transplantation is to evolve in ways that are felt to be beneficial for all concerned.

Attitude to Death↗

Cultural and psychological dimensions of human organ transplantation.

Human organ transplantation is practiced in local cultural worlds that shape beliefs about appropriate conduct for its development and application. The psychological response of individuals to the transplant experience mediate and condition its life-changing force in the context of family and community. In this paper, three cases are examined to illustrate the impact of cultural and psychological influences on human organ replacement therapies. First, we explore brain death and its implications for the definition of death and the procurement of organs. A case example from Japan provides the framework for addressing the cultural foundations that contribute to perceptions of personhood and the treatment of the body. Second, we examine marketing incentives for organ donation using a case from India where, until recently, explicit forms of financial incentives have played a role in the development of renal transplantation involving non-related living donors. Third, we focus on the psychological remifications of organ transplantation using a case that demonstrates the profound experience of being the recipient of the "gift of life". Resolution of scientific and ethical challenges in the field of organ transplantation must consider the complex and significant impact of cultural and psychological factors on organ replacement therapies.

Attitude to Health↗

Brachial plexus palsy and spinal subarachnoid pneumatosis following trauma.

The case of a 33-year-old male involved in a road traffic accident, resulting in brachial plexus palsy associated with subarachnoid pneumatosis, is described. A knowledge of the regional anatomy at the root of the neck is used to explain the patient's neurological signs and the mechanism of entry of air into the subarachnoid space.

Accidents, Traffic↗

Chondroid syringoma of the nose: report of a case.

Chondroid syringoma or mixed tumour of the skin is a rare benign tumour which can present on the face. We present here the case of a patient who underwent an excisional biopsy of a small painless nodule in the soft triangle of the nose for cosmetic reasons. The clinical presentation, histology and treatment, with review of the relevant literature, is discussed.

Adenoma, Pleomorphic↗

HLA antigens in Omanis with blinding trachoma: markers for disease susceptibility and resistance.

AIM: To determine the presence of HLA antigens in people with blinding trachoma. METHODS: Fifty Omanis with blinding trachoma were serologically typed for HLA A, B, C, DR, and DQ antigens and DNA typed for class II DR beta and DQ beta alleles and compared with a population of 100 healthy controls. RESULTS: chi 2 analysis of serological reactions did not reveal any significant differences in HLA antigen frequencies after correction of probability, although DR4, DR7, and DR53 were completely absent in the patients and all of the patients were HLA DQ1 positive. In the case of DQ1 the relative risk was 22.6 (95% confidence interval of 20.7-24.7). Class II DNA low resolution DR beta typing showed a significant increase in HLA DR16 (pc = 0.036, relative risk = 3.8) and a significant decrease in HLA DR53 (pc = 0.018, relative risk = 0.05). CONCLUSION: The finding that HLA DR16 (a DR2 subtype) is associated with susceptibility to blinding trachoma, a disease that is caused by an intracellular micro-organism, is consistent with reports of an HLA DR2 association with leprosy and tuberculosis, diseases also caused by an intracellular micro-organism. Similarly, resistance to leprosy is associated with HLA DR53 as is the case with blinding trachoma described here. It is postulated that HLA DR2 or subtypes in association with HLA DQ 1 may enable an intracellular micro-organism to enter the cell or are involved in presentation of peptides derived from intracellular micro-organisms to T lymphocytes initiating a delayed hypersensitivity or autoimmune reaction. These findings are the first report that genetic factors are of major importance in the development and protection against blinding trachoma.

Biomarkers↗

HLA antigens in an Omani population with dilated cardiomyopathy.

We have investigated the frequency of HLA antigens in 50 Omanis with idiopathic dilated cardiomyopathy to establish whether there are ethnic/racial differences in the reported HLA associations with this disease. There were no statistically significant HLA-A, B, C, DR or DQ antigen frequency differences between the patients and 247 healthy Omanis. THe reported association of HLA-DR4 with idiopathic dilated cardiomyopathy in the Caucasian population does not apply to the Omanis. This confirms the heterogeneity of this disease and points to ethnic/racial origins as important factors when examining the HLA association. This is particularly pertinent as HLD-DR4 has been strongly linked to autoantibody formation in idiopathic dilated cardiomyopathy in Caucasians. The lack of any HLA antigen association in Omanis would argue against the proposed HLA-linked autoimmune pathology of idiopathic dilated cardiomyopathy.

Cardiomyopathy, Dilated↗

Marketing human organs: the autonomy paradox.

The severe shortage of organs for transplantation and the continual reluctance of the public to voluntarily donate has prompted consideration of alternative strategies for organ procurement. This paper explores the development of market approaches for procuring human organs for transplantation and considers the social and moral implications of organ donation as both a "gift of life" and a "commodity exchange." The problematic and paradoxical articulation of individual autonomy in relation to property rights and marketing human body parts is addressed. We argue that beliefs about proprietorship over human body parts and the capacity to provide consent for organ donation are culturally constructed. We contend that the political and economic framework of biomedicine, in western and non-western nations, influences access to transplantation technology and shapes the form and development of specific market approaches. Finally, we suggest that marketing approaches for organ procurement are and will be negotiated within cultural parameters constrained by several factors: beliefs about the physical body and personhood, religious traditions, economic conditions, and the availability of technological resources.

Altruism↗

HLA antigens in Omani patients with vitiligo.

Fifty native Omanis with vitiligo were studied to compare the incidence of HLA ABC and DR antigens with a control population. HLA Bw6 was found in 82% of patients compared with 49% controls (Pc = 0.0009 RR = 4.56) and HLA DR7 occurred in 40% of patients and 9% in controls (Pc = 0.00075 RR = 6.17). HLA DR7 was significantly increased in those patients with acrofacial, compared to focal disease (57% vs. 24% P = 0.038). Sixty-six per cent of the patients in this study had parents who were consanguineous and a positive family history was only found in this group with an incidence of 32%. HLA Bw4 segregated 100% with patients with a positive family history compared with 48% in consanguineous patients without a positive family history (Pc = 0.011 RR = 23). Vitiligo appears to be associated with different HLA antigens in different ethnic groups.

Female↗

The binding of jacalin with rabbit immunoglobulin G.

Rabbit immunoglobulin G (IgG) was subjected to affinity chromatography on a column of jacalin-Sepharose 4B. While the majority of IgG molecules did not bind, a small fraction, representing about 25% of the total IgG applied, bound to jacalin-Sepharose 4B. The binding of rabbit IgG to jacalin was further evidenced by ELISA performed on jacalin coated microtitre plates. While the jacalin-retained IgG fraction displayed strong binding, the unretained fraction did not demonstrate any detectable binding. Upon SDS-PAGE, both the jacalin retained and unretained rabbit IgG fractions displayed identical protein profiles. Upon protein blotting it was demonstrated that jacalin binding sites were located only on the heavy chain of IgG. These results suggest that rabbit IgG molecules are heterogeneous with respect to their glycosylation patterns. A small fraction of rabbit IgG molecules binds jacalin and the process is probably mediated through O-linked oligosaccharides present on the heavy chain of IgG.

Animals↗

Maturation of immunoglobulin-A binding proteins in the seeds of jackfruit.

The accumulation of proteins in the jackfruit seeds was monitored by extracting seeds proteins at various stages of growth. The early developing seed had several protein bands distributed over a molecular weight range of 10-67 kDa. But the mature seeds contained fewer bands with two of them being prominent at 12 and 15.4 kDa. Upon isoelectric focusing, the mature seed proteins were resolved into several bands distributed over a pH range of 4-9. While the mature seed proteins contained powerful hemagglutinating activities, these were not detected in the early developing seed. In contrast, the early developing seed had immunoglobulin A (IgA) binding activity as determined by enzyme-linked immunosorbent assay (ELISA). By Western blotting it was found that the early developing seed contained a novel 10 kDa IgA binding protein that was not present in the mature seeds.

Carrier Proteins↗