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Biomedical subjects

E Ho

Publications and source records attributed to E Ho.

At least 19 recordsLinked to original sources

Polymorphism of HLA in the Romanian population.

We have investigated the HLA-class I and class II polymorphism in a population of 83 Romanians using conventional serology together with PCR amplification and oligonucleotide typing of HLA-class II genes. Romanians show a higher frequency of HLA-A11, B13, B18, B37, B39, B51 and DR2 than other European populations. HLA-DRB1*1501 and 1601 account for the high frequency of the serologic specificity DR2. In Romanians, HLA-DR2 is in linkage disequilibrium with HLA-B18 and HLA-Bw52 rather than with HLA-B7 as in the case in other Europeans. Unexpected HLA-DR2 haplotypes include HLA-DRB1*1502, DQA1*0102, DQB1*0601; HLA-DRB1*1602, DQA1*0102, DQB1*0502. Other unusual haplotypes include HLA-DRB1*0405, DQA1*03, DQB1*0302; HLA-DRB1*1305, DQA1*0103, DQB1*0603; and HLA-DRB1*1405, DQA1*0101, DQB1*05032. Analysis of the genetic distance between Romanians and other Europeans who have been studied serologically are consistent with the hypothesis that Romanians descend from Roman ancestors who colonized Dacia between the 1st century B.C. and 1st century A.D.

Base Sequence

Effect of anti-HLA and anti-idiotypic antibodies on the long-term survival of heart and kidney allografts.

Long-term survival of heart and kidney allografts is threatened by the development of chronic rejection. Analysis of the relationship between reversible acute rejection episodes and actuarial survival at 5 years showed an inverse correlation suggesting that early cellular events may trigger antibody-mediated chronic rejection. In both heart and kidney allograft recipients producing anti-HLA antibodies we found a significant decrease in the 5-year graft survival rate. However, there was heterogeneity among anti-HLA antibody producers with respect to the development of anti-idiotypic antibodies. The actuarial 5-year graft survival was significantly higher in patients with Ab2 compared to patients without.

Actuarial Analysis

Effect of recipient gender and race on heart and kidney allograft survival.

Study of long-term survival of heart allografts shows that AA males and females have lower graft survival rates than those observed in NAC recipients. Primary kidney allografts in AA males, but not females, also display lower 5-year survival rates compared to those observed in the corresponding populations of NAC. Comparison of graft survival in the overall population of male and female recipients of kidney allografts shows that females have higher graft survival rates, probably as a result of better HLA matching. The level of alloantibody activity in posttransplantation sera is similar in the two populations, suggesting that factors other than HLA mismatching may contribute to the higher degree of graft failure in AA recipients.

Actuarial Analysis

Clinical correlations with serum C1q levels in patients with rheumatoid arthritis.

Previous studies have suggested that serum C1q levels measured during the first 5 years of rheumatoid arthritis (RA) may be predictive of the extent of subsequent joint damage. To further evaluate the clinical significance of this marker in RA, levels of C1q were measured by radial immunodiffusion in serum samples from 107 well-characterized patients with RA. Mean levels of C1q were higher in patients with a disease duration less than or equal to 5 years (173 micrograms/ml) than in patients with a disease duration greater than 5 years (148 micrograms/ml) (P = 0.032). Serum C1q levels were correlated with total joint counts and activities of daily living scores, but no correlation was observed with erythrocyte sedimentation rates or with radiographic scores. The results suggest that C1q may be a useful early marker of disease activity in patients with RA.

Arthritis, Rheumatoid

Towards an epistemological basis for andragogy in midwifery education.

In designing the curriculum for pre and post registration midwifery courses, the author has utilised an andragogical model. This term refers to the art and science of teaching adults (Knowles 1978). The ideas that Knowles (1978) put forward about andragogy while not new, have been implemented in adult education and are certainly relevant to the modern practice of midwifery education. The aim of this paper is to examine the two extreme philosophical views about the nature of man and to provide an epistemological basis for andragogy in midwifery education.

Adult

Soluble HLA antigens, anti-HLA antibodies, and antiidiotypic antibodies in the circulation of renal transplant recipients.

Chronic rejection represents the major threat to long-term survival of organ allografts. It is presumed that this form of rejection is mediated by antibodies against mismatched HLA antigens of the graft. The presence and specificity of anti-HLA-antibodies in posttransplantation sera are, however, difficult to document. We have explored the possibility that anti-HLA antibodies form immune complexes with soluble HLA antigens released from the injured graft and/or that they are blocked by antiidiotypic, anti-anti-HLA-antibodies. Our data demonstrate that the long-term survival of renal allografts is significantly lower in patients who develop anti-HLA-antibodies following transplantation than in patients who do not form antibodies. Following depletion of soluble HLA antigens by magnetic immunoaffinity, we could identify anti-HLA-antibodies in 57% of the sera obtained from patients undergoing chronic rejection of kidney allografts, compared with 41% prior to antigen depletion. In patients tolerating the graft for 4 years or more, the corresponding frequencies of antibody-positive sera was 2% and 5% prior and following depletion of HLA antigens. The presence of HLA antigen/anti-HLA-antibody immune complexes in patients' sera was positively associated with chronic humoral rejection (P less than 0.0001). Patients who tolerated the graft in spite of having developed antibodies against one of its mismatched HLA antigens show specific antiidiotypic (anti-anti-HLA-antibodies). Such antiidiotypic antibodies were not found in sera from patients with chronic rejection (P = 0.005). This indicates that antiidiotypic antibodies may delay the progression of chronic humoral rejection.

Antibodies, Anti-Idiotypic

The role of anti-HLA antibodies in heart transplantation.

The major threat to long-term survival of heart allograft recipients is the development of graft atherosclerosis, which seems to be a manifestation of chronic rejection. To assess the role of anti-HLA antibodies in heart allograft rejection we studied 107 patients and compared the survival of recipients who formed anti-HLA antibodies with the survival of recipients who developed no antibodies. At 4 years the actuarial survival was 90% in the nonproducer group and 38% in antibody-producers (P = 0.038). We further explored the possibility that HLA antigens from the injured graft are released into the circulation and can be found in the serum either free or complexed with anti-HLA antibodies. This hypothesis was confirmed by the finding that the frequency of sera containing soluble HLA antigens from the graft or immune complexes of HLA alloantigens with anti-HLA antibodies was significantly higher in patients who rejected compared with patients with successful heart allografts (P less than 0.05). Following depletion of soluble HLA antigens, anti-HLA antibodies became detectable in 53% and 74% sera obtained during the first and second year posttransplantation, respectively, from patients undergoing chronic rejection. Long-term survivors showed a significantly lower (P less than 0.001) frequency of anti-HLA antibodies in sera depleted of HLA antigens. Lastly, studies of anti-anti-HLA-A2 and A3 antibodies in recipient sera suggest that quiescence is maintained by antiidiotypic antibodies.

Antigen-Antibody Complex

Comparison of nicorandil-induced relaxation, elevations of cyclic guanosine monophosphate and stimulation of guanylate cyclase with organic nitrate esters.

Nicorandil increases cyclic 3'5'-guanosine monophosphate (cGMP) in vascular smooth muscle. However, high concentrations are required to activate guanylate cyclase (GC). We examined the relationship between activation of GC, increases in cGMP and relaxation in canine mesenteric artery and vein, renal and coronary artery and thoracic aorta. Nicorandil (10-100 microM) relaxed in each of the blood vessels. Relaxation was associated with elevations of cGMP but independent of release of endothelium-derived relaxing factor, and inhibited by methylene blue and hemoglobin. The organic nitrate esters nitroglycerin, pentaerythritol tetranitrate, isosorbide dinitrate, 2-isosorbide mononitrate, and 5-isosorbide mononitrate each behaved in a similar manner. In each blood vessel pentaerythritol tetranitrate was the most potent and 5-isosorbide mononitrate the least potent relaxant and stimulant of cGMP. Each of the organic nitrate esters (1 microM to 1 mM) except nicorandil stimulated soluble GC activity in the presence of 10 mM cysteine. Nicorandil (EC50 38 mM) increased GC activity. Moreover, nicorandil (0.1 microM to 30 microM) did not inhibit cGMP phosphodiesterase. The EC50 for vascular relaxation was directly correlated with the EC50 for elevation of cGMP for each of the agonists in each blood vessel type. The EC50 for activation of GC was directly related to the reciprocal of the rate constant for nitric oxide formation for each of the organic nitrate esters. However, a direct correlation existed between the EC50 for activation of GC and the EC50 for 1) elevation of cGMP and 2) relaxation, for each of the organic nitrate esters except nicorandil. Thus, the high concentrations of nicorandil required to activate GC cannot account for the low concentrations required to elevate cGMP or relax smooth muscle. We postulate that nicorandil may interact with a membrane receptor or release a second messenger, distinct from nitric oxide or endothelium-derived relaxing factor, which then activates GC. This may represent a physiologic mechanism for regulation of GC activity in smooth muscle.

3',5'-Cyclic-GMP Phosphodiesterases

Lumbar spondyloptosis. A long term follow up of three cases.

This paper reports the long term results of 3 patients with lumbosacral spondyloptosis who were treated by closed reduction, followed by 6 to 12 weeks plaster cast immobilisation, posterior fusion and finally anterior fusion after a further 3 to 6 months. The follow up was from 7.5 to 10.5 years. Spondyloptosis was diagnosed by estimating the slip angle and the percentage slip. The initial slip angle ranged from 40 degrees to 55 degrees with 46%-91% slip. The average improvement in the slip angle after reduction was 82% with 74% improvement in slip. There was some loss of correction in every case by the end of treatment: the average improvement in slip angle was 59% (36%-78%) with an average 52% (25%-69%) correction of slip. Fusion was obtained in every case and the clinical results were very satisfactory.

Adolescent

[A case report of redo A-C bypass for MCLS performed 13 years after initial surgery].

This is the first report of re-aortocoronary bypass for Kawasaki's disease. The patient is a 22-year old female. She was afflicted with Kawasaki's disease at the age of 6 and had the symptom of angina pectoris at the age of 9. She went through the first aortocoronary bypass, to the left anterior descending artery (LAD) and the right coronary artery (RCA) with saphenous vein graft (SVG). After the first operation, the graft to LAD occluded totally, but she remained asymptomatic and well for 11 years. She had a sudden recurrence of anginal attack at the age of 20. The examinations confirmed ischemia of the anterior wall (LAD area) and the lateral wall (LCX area). Coronary angiography revealed patent SVG with a moderate sign of sclerotic change. We decided on re-aortocoronary bypass, left mammary artery to LAD and gastroepiploic artery to LCX, when she was 22-years old. LIMA was anastomosed to LAD, but LCX was not revascularized, because LCX was not identified and exposed in the operation. In spite of incomplete revascularization, postoperative stress ECG test was negative. Tl-myocardial scintigram confirmed no ischemia of the anterior wall and greatly reduced ischemia in the lateral wall. She became asymptomatic and returned to normal life.

Adult