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D Middleton

Publications and source records attributed to D Middleton.

At least 127 records · Page 7Linked to original sources
PubMed1993

DNA HLA-DR typing results of 4000 kidney transplants.

Recipients (4076) and donors (3325) of kidney transplants performed at 110 transplant centers were typed for HLA-DRB by the DNA RFLP method. The discrepancy rate of replicate samples distributed among 8 participating laboratories was a low 2.6%. The discrepancy rate between RFLP-DRB and serological HLA-DR typings was 25.0% for organ donors and 27.6% for kidney recipients. Discrepancy rates at the different transplant centers ranged from 9.7% to 86.7%. The discrepancies consisted of antigens being incorrectly interpreted by serology (16.8%), and of serological "blanks" turning out to be definable alleles by the DNA method (10.8%). The alleles that were mainly affected by discrepancies were DR1, DR8, DR10, DR12, DR13, DR14, DR16, DR17.2, and DR18.

Alleles↗
PubMed1993

Analysis of HLA-DR matching in DNA-typed cadaver kidney transplants.

The effect of matching for HLA-DR antigens was analyzed retrospectively in 3455 cadaver kidney transplants that were typed by the DNA-RFLP method. HLA-DR matching improved the one-year graft survival rate significantly (P < 0.01). Importantly, in 718 first transplants in which the number of mismatches assigned by serological typing was different from that assigned by DNA typing, only the DNA results showed a significant impact of matching on graft outcome (P = 0.03). These results demonstrate that DNA typing is clinically relevant. We were unable to confirm that the HLA-DR6 specificity or the DR6-split DRB1*1302 are associated with poor graft survival.

Cadaver↗
PubMed1992

Structural relationship between the two IgY of the duck, Anas platyrhynchos: molecular genetic evidence.

cDNA clones encoding the H chains of the 7.8S and 5.7S IgY of the White Pekin duck have been isolated and sequenced. The H chain of the 7.8S IgY possesses four C region domains and thus resembles the H chain of chicken IgY with which it shows, in the C region, 54% inferred amino acid sequence identity, and complete conservation of the C region cysteine and tryptophan residues. The H chain of the 5.7S IgY possesses only two C region domains, that are virtually identical to CH1 and CH2 of the 7.8S IgY H chain. Although Southern blot genomic analysis did not resolve whether the two transcripts encoding the H chains of the 7.8S and 5.7S IgY are derived from one or two H chain-encoding genes, the CH 1, 2, 3, and 4 exons are apparently colinear, and no evidence was found for a separate locus in which CH1 and 2 exons were present and CH3 and 4 exons were lacking. The VH domain-encoding sequences of the cDNA for the two IgY H chains showed high similarity in the inferred VH gene (93% nucleotide and 91% inferred amino acid identity) and in the inferred JH segment (89% nucleotide and 93% inferred amino acid identity) but low similarity in the D region (26% nucleotide and 7% inferred amino acid identity). Genomic Southern blot hybridization analysis showed multiple VH-hybridizing sequences represented on up to 20 restriction fragments.

Amino Acid Sequence↗
PubMed1992

DNA typing: an important step forward? Collaborative Transplant Study.

In a collaborative project which was supported by 96 transplant centers, DNA typing of HLA-DR antigens was carried out on over 7,000 transplant donors and recipients at 8 participating laboratories. Approximately 25% of the individuals were found to have been typed incorrectly by serological means. An analysis of over 2,500 first cadaver kidney transplants showed a significant correlation of matching for the HLA-DR antigens in transplants where the serological typing was confirmed by DNA typing. In transplants where the serological typing was found to be incorrect, the analysis of serological HLA-DR mismatches resulted in no correlation with graft outcome whereas a significant correlation was found when the corrected DNA typed HLA-DR antigens were analyzed. Transplants which had been reported to the Collaborative Transplant Study based on serological typing as matched for HLA-A, -B, -DR or HLA-B, -DR were found to have a superior graft survival rate only if HLA-DR compatibility was confirmed by DNA typing.

DNA Fingerprinting↗
PubMed1992

HLA class II frequencies in celiac disease patients in the west of Ireland.

Restriction fragment length polymorphism analysis, using a single restriction enzyme TaqI-multiple-probe system for HLA-DRB1-DQB1 and -DQA1, was used to determine HLA-DR and -DQ frequencies in 56 unrelated celiac patients and 47 unrelated controls from the west of Ireland. In addition, HLA-DPB1 allelic frequencies were determined in the same group of patients and controls by using the technique of enzymatic DNA amplification of the polymorphic second exon of HLA-DPB1 genes in conjunction with sequence-specific oligonucleotide probing. The results suggest that HLA-DQ rather than HLA-DR is more important in conferring susceptibility to celiac disease. Furthermore, no association between HLA-DP and celiac disease was found in this study.

Adolescent↗
PubMed1992

Frequency of HLA-DPB1 alleles, including a novel DPB1 sequence, in the Northern Ireland population.

HLA-DPB1 allele frequencies in 150 unrelated normal individuals from Northern Ireland were determined using oligonucleotide typing methods. HLA-DPB1*0401 was the most common allele in the population possessed by 75.3% of subjects, followed by DPB1*0201 (20.7%). In addition to these alleles, only HLA-DPB1*0402, -DPB1*0301, and -DPB1*0501 were present in subjects at frequencies greater than 10%. The results in this study are in broad agreement with other Caucasoid studies, but there is regional and ethnic variation in HLA-DP allele frequencies. Three DPB1 alleles were found to be in linkage disequilibrium with HLA-DR antigens determined by RFLP, namely, DPB1*0101 with DRw17 (Dw24 associated) RFLP, DPB1*0501 with DRw13-Dw19 RFLP, and DPB1*1901 with DRw13-Dw18 (Dw25 associated) RFLP. One individual revealed a novel DPB1 pattern of probe reactivity, which following DNA sequencing was found to be HLA-DPB1*2001. To assess the system used and to compare consistency of results between laboratories, 62 cell lines were oligotyped for HLA-DP. The results revealed the system described here to be extremely accurate and showed excellent agreement of HLA-DP typing results for cell lines between laboratories.

Alleles↗
PubMed1992

Sparganosis in the monotremes Tachyglossus aculeatus and Ornithorhynchus anatinus in Australia.

Sparganosis in the echidna, Tachyglossus aculeatus, is characterized by large subcutaneous masses that may be confused with neoplasms. Plerocercoids, believed to be Spirometra erinacei, were found in the ventral or lateral subcutaneous tissues of three echidnas. In each case there was a prominent fibrous mass < or = 12 cm in diameter enclosing plerocercoids, which were surrounded by an intense inflammatory infiltrate dominated by plasma cells and lymphocytes, with focal suppuration. Multiple, small (< or = 2 mm) plerocercoids were present in the lungs and pleural cavity of a fourth echidna that died due to severe pneumonitis. Several plerocercoids also were found in the lung of a platypus (Ornithorhynchus anatinus) associated with parenchymal compression and focal pneumonia.

Animals↗
PubMed1991

Survival of DNA HLA-DR typed and matched cadaver kidney transplants. The Collaborative Transplant Study.

The clinical value of serological HLA matching for cadaver kidney transplantation remains uncertain because the success rate for HLA-matched cadaver transplants is lower than that of HLA-matched sibling grafts. Up to 25% of serological HLA-DR typings may be incorrect when compared with a more accurate DNA-RFLP method, and we have now examined whether incorrect HLA-DR typings account for the lower than expected success rates of HLA-matched cadaver transplants. 58 transplant centres took part in this study and DNA was extracted from over 4000 samples of frozen tissue at the study centre. 8 laboratories then completed blind RFLP typing for HLA-DR. Serological typing data were reported by individual transplant laboratories. 29 of 107 transplants (27%) that were reported as HLA A, B, DR compatible and 76 of 273 (28%) transplants that were reported as HLA B, DR compatible according to serological typing were found to be HLA-DR mismatched by DNA typing. The one-year transplant success rate for DNA-matched HLA, A, B, DR grafts was 87% compared with 69% for mismatched grafts (p less than 0.02); the corresponding success rate for DNA-matched HLA B, DR grafts was 85% compared with 72% for mismatched grafts (p less than 0.01). Many transplants that were previously thought to be HLA matched are mismatched, and this finding may account for previously unexplained graft failures.

Cadaver↗
PubMed1991

Techniques used to define human MHC antigens: restriction fragment length polymorphisms.

Polymorphisms within the HLA-DRB1, -DRB3, -DQB1 and -DQ A1 genes are detectable using restriction fragment length polymorphism (RFLP) analysis. DNA is isolated from EDTA-treated blood or from spleen or lymph nodes. The DNA is digested to completion with the restriction endonuclease TaqI and resolved using agarose gel electrophoresis. The DNA after denaturation is then transferred to a nylon membrane (Southern blotting) and hybridised with radiolabelled cDNA probes: HLA-DR beta pRTV1, HLA-DQ beta pII-beta-1 and HLA-DQ alpha pDCH1. After autoradiography the membrane is dehybridised prior to rehybridisation. This system is very useful in those situations where serological assignment is difficult due to poor quality or low numbers of circulating B cells and where there is a lack of reliable antisera for certain specificities. The RFLP techniques can also define subtypes of DR and DQ serological specificities. However, certain alleles have the same RFLP. In some instances by identifying the DQ allele the DR allele can be determined by association due to linkage disequilibrium (e.g., DRw17-Dw25-DQw2 and DRw13-Dw25-DQw6). In other instances (e.g., DR1 and DRBr), the problem can be resolved using serology. In addition the RFLP system cannot be applied prospectively to the cadaver donor situation because of time restrictions. Thus the RFLP system complements existing serological techniques. However, it can be very useful as a quality control for the serological methods especially in the assessment of the quality of antisera and in the determination of discrepancies between centres.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗