Myf-3 hypermethylation in malignant lymphoproliferative disorders.
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Biomedical subjects
Publications and source records attributed to P H Kay.
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A patient undergoing coronary artery bypass was found to have a giant epicardial lipoma weighing 1.36 kg which was excised uneventfully. The radiological and pathophysiological features are considered, and the options for management discussed.
A cross-sectional study of 50 randomly selected patients 12-36 months following mechanical heart valve replacement with Bjork-Shiley tilting disc valves was undertaken to investigate the factors which affect perception of, and reaction to, sounds generated by mechanical heart valves implanted in patients. Numerous problems were generated by the valves, including annoyance (68%), sleep disturbance (52% in patients; and 46% in patients' partners), interference with concentration (36%) and social embarrassment (28%). These findings are not affected by the measured level of sound or any variation in the number or anatomical position of the valve(s), though age and sex do seem to matter, more problems being reported by younger patients and those of the female sex. Aspects of the patient's personality did not seem to alter the difficulties experienced, though a high level of psychological morbidity was identified in the group as a whole. Most patients experience problems due directly to the noise generated by their valve and should be adequately warned of this before operation. This should also be taken into consideration in designing and evaluating new valve prostheses.
Four allelic forms of the immunoglobulin lambda light chain constant region (C lambda) genes are found in the caucasoid population and are recognised by the presence of Eco RI restriction fragments of sizes 8, 13, 18, and 23 kb hybridising with a C lambda probe. The less common allelic forms of the C lambda genes are marked by the 13, 18, and 23 kb fragments, and these may be misinterpreted as rearranged fragments derived from a monoclonal population of B-cells. The 13, 18, and 23 kb alleles result from the insertion of one, two, and three copies, respectively, of a 5.2 kb repeat unit that can be demonstrated by hybridising genomic DNA digested with Hind III with a C lambda probe. Using selected histologically and immunophenotypically well-defined cases, we assessed the usefulness of the 5.2 kb Hind III/C lambda fragment in distinguishing between rearrangements indicative of a B-cell lymphoma and germline configurations representing uncommon allelic forms of the C lambda genes. From these studies, we conclude that Hind III digestion should routinely be performed when using the C lambda probe to assess B-cell monoclonality. Identification of the 5.2 kb Hind III fragment obviates the need to examine DNA from normal peripheral blood granulocytes to exclude allelism of the C lambda genes in cases exhibiting the uncommon restriction fragments after Eco RI digestion.
Polymorphism of the myogenic gene, Myo-D1, has been sought to examine genetic mechanisms which control skeletal muscle development. By Southern analysis, three restriction-fragment length polymorphisms (RFLPs) have been found in various mouse strains using the TaqI, SacI and BglII restriction endonucleases and a full-length cDNA Myo-D1 probe. Reference to the distribution of RFLPs in different mouse strains derived from Mus mus (M.m.) domesticus and M.m. musculus subspecies suggests that Myo-D1 rearrangements are subject to nonrandom association. The biological significance of RFLP of the Myo-D1 gene is yet to be determined.
A retrospective analysis of the long-term results of using the Ionescu-Shiley pericardial bioprosthesis in the tricuspid position was carried out on 73 patients (8 men, 65 women). Of these procedures, ten were tricuspid valve replacement alone and the remainder were in combination with other valve procedures. The mean follow-up was 9.6 years (range, 4 to 18 years). The mean age of the patients was 53 years (range, 27 to 78 years). Seventy-one of the patients suffered tricuspid valve dysfunction from rheumatic heart disease. There were 13 postoperative deaths (within 30 days), giving a mortality rate of 17.8%. The actuarial survival at 10 years was 71% +/- 4.2%. Of the survivors, 49 (79.6%) were in functional class I or II. Primary tissue valve failure in the tricuspid position occurred in 1 patient 12 years after implantation and required reoperation. In another patient bioprosthetic tricuspid valve endocarditis developed. There was no incidence of thromboembolic complications. We conclude that the Ionescu-Shiley pericardial bioprosthesis was a satisfactory prosthesis in the tricuspid position in patients with acquired valvar dysfunction.
Mice deficient in the fifth component of complement are known to be extremely susceptible to lethal challenge with Candida albicans. However, male mice, that have significantly higher concentrations of serum C5 than females, were markedly more susceptible to infection. This difference was observed in both susceptible (CBA/H) and resistant (BALB/c) mice. Levels of serum C3 likewise showed no correlation with susceptibility.
To investigate the safety and efficacy of postoperative autologous blood transfusion (AT) using the Shiley hardshell venous reservoir, a prospective, randomised, controlled study was carried out in two matched groups of twenty patients undergoing elective coronary artery bypass surgery. The mean volume of shed mediastinal blood reinfused in the first 6 h postoperatively was 371.7 +/- 63.23 ml. Use of homologous blood was reduced from 760.5 +/- 108.37 ml in the control patients to 466.25 +/- 87.44 ml in the AT patients, a reduction of 38.7% (p less than 0.05). There was no statistically significant difference in the clinical outcome, overall blood loss, use of platelets, fresh frozen plasma and colloids, haematological indices, renal and hepatic functions, or clotting mechanism, although there was a reduction in the fibrinogen level in the patients who received AT (p less than 0.05). Mediastinal blood did not clot and was defibrinogenated. It contained significant levels of haemoglobin (8.175 +/- 0.506 g/dl), platelets (96.55 +/- 10.39 per mm3 10(3)), protein (42.5 +/- 1.13 g/l), calcium (2.385 +/- 0.054 mmol/l) and was well oxygenated (PO2 = 20.46 +/- 0.81 kPa). No patients developed bacteraemia or had any AT-related infections. We conclude that postoperative autologous transfusion using the Shiley hardshell venous reservoir is a safe and efficient method for reducing postoperative homologous blood requirement after coronary artery bypass surgery.
The importance of complement in the potentiation of the immune response is now firmly established. More recently, however, evidence has accumulated which suggests that complement may influence biological events following non-immunologically mediated tissue damage. Several of the many different genetically controlled structural forms of complement components, which are now recognised, have been shown to influence immunoregulation and disease susceptibility. Furthermore, molecular and genetic analyses have revealed that some of the regulatory elements such as S-protein may have multiple biological functions. As a consequence, it is likely that reference to detailed functional and molecular properties of various complement components, with special reference to regulatory elements will provide new insights into mechanisms of pathogenesis of disease.
Juvenile insulin-dependent diabetes mellitus develops in susceptible children exposed to unknown environmental factors. If the genes responsible for susceptibility could be identified, it should be possible to understand the method of injury to beta cells as well as identify the infectious or other agents involved. For a decade it has been known that one or more of the susceptibility genes must be within the major histocompatibility complex (MHC). Unfortunately, there are at least 20 different genes in the complex and it has not been possible to determine which are actually responsible. Therefore, we undertook to apply a new concept and new technology to the problem. Over several years we have shown that the diabetogenic gene(s) are contained within conserved ancestral haplotypes which can then be used as markers of the DNA which must contain the gene(s), whether present in a patient or an asymptomatic carrier such as a parent. This approach avoids the confusion which has resulted from using DR3 or DR4 which are only sometimes associated with the relevant genes. The new technology involves pulsed field gel electrophoresis which allows examination of large fragments of DNA containing all of the MHC, and makes it possible to identify deletions and duplications which were otherwise undetectable. In the first instance we compared two ancestral haplotypes [1,8,3 (8.1) and 18,F1,3 (18.2)] known to contain the relevant genes, and contrasted the DNA with that of another ancestral haplotype [3,7,2(7.1)] which is known to lack these genes. We have shown that there are three major deletions common to the two carrier haplotypes but absent in the protective haplotypes.(ABSTRACT TRUNCATED AT 250 WORDS)
To reduce the risk of damage to the anterior surface of the right ventricle after resternotomy, it has been recommended that the pericardium be closed with a patch after open heart operations. We have examined 4 patients undergoing resternotomy for the third time 3 to 8 years after bovine pericardium valve replacement. On each occasion the pericardium was closed with a patch of bovine pericardium. In all cases, the patch was frozen to the inner aspect of the sternum, increasing the difficulty of resternotomy. Histological examinations of the patches confirmed dense fibrous connective tissue, patchy calcification, and foreign body giant cell reaction. Bovine pericardium appears to increase the difficulty of repeat cardiac operations. We recommend its use be discontinued.
We describe here an Nco I restriction fragment length polymorphism of tumor necrosis factor carried by the 8.1 (HLA-A1,B8,BfS,C4AQ0,C4B1,DR3) and the 44.1 (HLA-B44,BfS,C4A3,C4BQ0,DR4) ancestral haplotypes associated with complications of rheumatoid arthritis. By examining multiple examples of these and other ancestral haplotypes it was seen that 8.1 and 44.1 ancestral haplotypes yield fragments of approximately 5.5 kb while many other ancestral haplotypes carry fragments of approximately 10.5 kb. The polymorphism is associated with the ancestral haplotype rather than the HLA-B or -DR allele defined by conventional serology.
The molecular map of the human major histocompatibility complex was examined in multiple examples of various Caucasoid and Japanese major histocompatibility complex supratypes using pulsed field gel electrophoresis. Extensive differences in restriction fragment lengths were observed. However, each supratype showed specific genomic characteristics including deletions, duplications, or insertions supporting the hypothesis that these supratypes are markers of conserved ancestral haplotypes. Some of the gene arrangements are consistent with the deletions or duplications previously described or suggested by conventional DNA techniques and protein typing, while others have not been recognized previously. Characterization of the gene organization within disease-associated ancestral haplotypes will provide new insights into the functional role and evolution of the major histocompatibility complex.
A small solid state transducer was used to measure pericardial pressure (PP) in 13 pediatric patients (mean age 18 months) at hourly intervals for 24 h following cardiac surgery. The mean PP following closed cardiac surgery via a left thoracotomy (group 1: 5 patients) was 2.7 +/- 1.4 mmHg and did not change with time. Maximum PP occurred during isovolumic relaxation of the ventricle rising to a peak at the onset of the 'a' wave of the central venous pressure (CVP). PP was strongly correlated with CVP (r = 0.58, P less than 0.001) but not with airways pressure (r = 0.27, P less than 0.2). Mean PP in the 3 patients undergoing transatrial surgery (group 2) was 4.5 +/- 2.7 mmHg (group 1 vs group 2, P less than 0.001). PP was significantly raised in the 2 patients undergoing transventricular correction of Fallot's tetralogy (group 3, PP = 10.2 +/- 3.2 mmHg; group 3 vs group 2, P less than 0.001) and in the 3 patients undergoing homograft conduit reconstruction of the right ventricular outflow tract for truncus arteriosus (group 4, PP = 9.3 +/- 2.6 mmHg; group 4 vs group 2, P less than 0.001). The results confirm that PP is a mathematical function of the expansile forces of the heart and the restricting forces of the pericardium and mediastinum. Patients with pulmonary regurgitation or pulmonary hypertensive crisis leading to increased right ventricular end diastolic dimension or a space occupying conduit have a high PP and are therefore at risk of atypical tamponade. In this situation splinting open the chest may reduce PP and break the cycle of falling cardiac output.
The genomic organization of the human MHC was examined in multiple examples of six different supratypes using pulsed field electrophoresis (PFGE) after digestion of genomic DNA with infrequency cutting restriction endonucleases. Differences in restriction fragment length and band intensity were shown to be specific for each supratype. Mapping of the MHC revealed that each supratype contains previously undescribed deletions and insertions between HLA B and DQ regions.
The hypothesis that complement is important in the host response to human immunodeficiency virus (HIV) was tested. Complement C4 and Bf allotypes were determined in 26 patients who fulfilled the diagnostic criteria for persistent generalised lymphadenopathy due to HIV, 72 homosexuals who were negative for antibody to HIV, and 185 control subjects drawn from the local population. HLA-A, B, and DR were also typed and the phenotypes examined for the presence of supratypes and C4BQ0. Eleven patients (42%) had C4B null alleles compared with only 13 (18%) homosexuals who were negative for antibody and 28 (15%) controls. From estimates of gene frequencies the difference between the patients with lymphadenopathy and the controls was significant after conservative correction. In the patients only a minority (six) of the C4B null alleles were contained within ancestral haplotypes. Together with the fact that C4 null alleles result in partial deficiency of C4, this finding suggests that products of complement genes are important in infection with HIV or its consequences, or both. A role is proposed for complement and Fc receptors.
Class III gene rearrangements have been examined in Thai/Chinese individuals with supratypes bearing defective or null C4 alleles. Genomic DNA from C4 null supratypes was probed with an almost full-length 21-OH probe following digestion with Taq I and Kpn I. The HLA-B17 C4A3 BQ0 BfS DR3 Thai/Chinese supratypes (which may be associated with insulin-dependent diabetes mellitus in Orientals) lacks a 3.2 kb Taq I and a 3.9 kb Kpn I fragment hybridizing with the 21-OH probe. Similar gene rearrangements are found in Caucasoid diabetogenic supratypes HLA-B18 C4A3 BQ0 BfF1 DR3 and HLA-B8 C4AQ0 B1 BfS DR3. Interethnic comparisons suggest that class II and class III interactions may be important in disease susceptibility. By contrast, neither of two Thai/Chinese supratypes with C4AQ0 appear to have major class III gene rearrangements; disease association studies will determine the significance of C4 deficiency per se. As in Caucasoids, the electrophoretically fast C4 allele, C4A6, in Orientals has been shown to correlate with a 12 kb Bgl II fragment hybridizing with a C4 probe. It is likely that the HLA-B17 C4A6 B1 BfS DR7 supratype marks a highly conserved MHC chromosomal segment.