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Biomedical subjects

A S Daar

Publications and source records attributed to A S Daar.

At least 73 records · Page 4Linked to original sources
PubMed1993

Identification of a novel 4 kDa immunoglobulin-A-binding peptide obtained by the limited proteolysis of jacalin.

Jacalin, an IgA-binding lectin from jackfruit (Artocarpus heterophyllus) seeds, was isolated by the passage of PBS extracts of seeds over an affinity matrix containing IgA-Sepharose-4B. It was further purified by HPLC. When analyzed by SDS-PAGE under both reducing and nonreducing conditions, the native jacalin was dissociated into two subunits of 12 and 15.4 kDa. Both the subunits could bind IgA. Peptide mapping performed with radioiodinated jacalin indicated that both the subunits were susceptible to proteolysis by Staphylococcus aureus V8 proteinase. One degradation product was a small peptide of 4 kDa. This small proteolytic fragment also bound IgA. The amino-termini of the two major IgA binding subunits, 12 and 15.4 kDa, were identical. The 4 kDa IgA-binding proteolytic fragment of jacalin had a different amino-terminal sequence, suggesting that the region of jacalin which binds IgA does not remain close to the amino-terminus of the peptide.

Amino Acid Sequence↗
PubMed1992

A controlled trial of surgery for trachomatous trichiasis of the upper lid.

The effectiveness of commonly used procedures to correct trachomatous trichiasis of the upper lid was examined in a clinical trial in Oman. Lids were graded as having minor trichiasis (five or fewer lashes), major trichiasis (more than five lashes), and defective lid closure. Randomly allocated surgery specific for lid grade was completed in 384 lids, of which 369 (96%) were followed up once or twice approximately 9 and 21 months after surgery. The definition of operative success included no evidence of trichiasis and complete lid closure. Tarsal rotation was the most effective operation and was successful in 80% of cases of minor trichiasis, compared with success rates of 29% for electrolysis and 18% for cryoablation. Tarsal rotation was successful in 77% of cases of major trichiasis, compared with a 41% success rate for tarsal advance and rotation. Surgery for major trichiasis produced a significant improvement in visual acuity in operated vs nonoperated fellow eyes in a regression model incorporating the between-eyes correlation of visual acuity.

Cornea↗
PubMed1992

Rewarded gifting.

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Bioethics↗
PubMed1991

The case for using living non-related donors to alleviate the world wide shortage of cadaver kidneys for transplantation.

There continues to be a shortage of kidneys for transplantation even in countries with developed cadaver donor programmes. It is becoming clearer that cadaver donation will probably never satisfy the demand for kidneys, and living donor transplants are bound to play an important role in transplantation, more so in developing countries. Living non-related donation played a significant role in the early days of clinical renal transplantation, but fell into disrepute partly because of the activities of a few individuals and a few transplant centers that profited from commerce in human organs. However, it has always been recognised that living non-related donor (LNRD) renal transplantation per se was ethically acceptable. With the improvement in the results of renal transplantation, the persistent shortage has led to a reassessment of LNRD transplantation. Evidence indicates that both the public and the profession are in favour of this source of donation, although many transplant units are still reluctant to use it. However, more and more units, in both the developed and the developing world, are now performing such transplants. Where this is done ethically, the results appear to be excellent. We strongly believe that spouses, distant relatives and genetically non-related individuals who have an enduring relationship should be permitted to donate.

Asia↗
PubMed1991

Organ donation--world experience; the Middle East.

Many countries in the Middle East began renal transplantation in the late 1970s and the 1980s. In many countries transplantation has evolved through distinct stages of development, and at present living-related donors continue to be the main source of kidneys. Islamic opinion has been strongly in favour of transplantation of organs from both living and cadaveric donors. Brain death as a criterion of death was accepted by Islamic Jurists in 1986, and in Saudi Arabia about 35% of all transplants are from cadaveric donors. Some patients continue to go to neighbouring countries to buy kidneys for transplantation; there is evidence that this practice has resulted in unacceptable morbidity and mortality, and is currently associated with a risk of at least 1:18 of acquiring HIV infection. Extrarenal solid organ transplantation is very new, with heart transplants being performed in Turkey, Jordan, and Saudi Arabia. Liver transplants have been initiated in Turkey and Kuwait. The favourable religious rulings and the resources available should enable transplantation to develop rapidly in the next few years in the Middle East and West Asia.

Brain Death↗
PubMed1990

High mortality among recipients of bought living-unrelated donor kidneys.

Between June, 1984, and May, 1988, 130 patients from three renal units in the United Arab Emirates and Oman went of their own accord to Bombay, where they bought, through brokers, kidneys from living unrelated Indian donors for US$2600-3300. 131 transplants were done, and the 122 patients who survived the perioperative period returned to their original renal units for follow-up. Altogether there were 25 deaths (16 before the end of 3 months, 4 in the next 3 months, and 4 more by the end of the first year), which gave a patient survival rate of 81.5% at 1 year. The patients who died had multiple complications, but infection was the commonest known cause of death. Patients were not properly instructed about their treatment, and little or no information was given to doctors following up the patients, criteria of suitability for transplantation were not strict, and patients were exposed to serious infections (including human immunodeficiency virus infection). In addition, the availability of living-donor programmes slows down attempts to establish cadaver-donor transplant programmes.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Ethics and commerce in live donor renal transplantation: classification of the issues.

Renal transplantation is now very successful. A shortage of kidneys continues to be a problem. Attempts to increase the supply have recently led to unethical practices, but the issues in the discussion of the ethics need clarification. We propose a classification that we believe will help to achieve this for living donor renal transplantation. This can be considered under five categories: (1) living-related donation; (2) emotionally related donation; (3) altruistic donation; (4) "rewarded" gifting; and (5) rampant commercialism. Ethical issues for categories 1, 2, and 3 are either esoteric or have been resolved. Category 4 needs further discussion and elucidation and should be the area of concentration. Category 5 we perceive to be unethical.

Altruism↗