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Biomedical subjects

D Middleton

Publications and source records attributed to D Middleton.

At least 19 recordsLinked to original sources
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

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↗
PubMed1991

Five new TaqI DRB1 polymorphisms.

Five new restriction fragment length polymorphisms (RFLPs) using TaqI and a DR beta probe have been found in Caucasian individuals. The families of these individuals have been tissue typed by serological and RFLP methods. The new RFLPs are similar to previously established RFLPs except for the size of one fragment in each instance.

Blood Donors↗
PubMed1991

HLA-DR and DQ DNA genotyping in multiple sclerosis patients in Northern Ireland.

DNA from multiple sclerosis (MS) patients and healthy control individuals from the Northern Ireland population, was assessed by restriction fragment length polymorphism (RFLP) analysis to look for disease-associated polymorphisms. HLA-DR and -DQ allogenotyping was performed using a single enzyme (TaqI)/Multiple probe system. The TaqI/DR beta RFLPs correlate well with serologically defined specificities and in addition detect further subtypes of these associated with DQ or Dw specificities. The results confirm an association of MS with DR beta 15 and show a decreased frequency of DR beta 4 in the patients. An increased frequency of DR beta 17 in patients negative for DR beta 15 was also found. There is a decrease in the frequency of the TaqI/DQ beta 3 (TA10 + ve) RFLP and the TaqI/DQ alpha 2LL genotype in the MS patients, these not being associated with DR beta 15. In addition RFLP analysis of the DPA1 and DPB1 genes reveals an MspI/DP beta 3.0-kb fragment which occurs at a higher frequency in the patients than in the controls.

Gene Frequency↗
PubMed1991

HLA antigen frequencies and Wegener's granulomatosis.

Previous reports of an association between HLA tissue type and Wegener's granulomatosis are contradictory. By using for the first time a highly sensitive restriction fragment-length polymorphism (RFLP) analysis in addition to standard microcytotoxicity assays, the largest series yet investigated (41 patients) was tissue typed. No association was found between any specific HLA antigen and Wegener's granulomatosis. Although the condition appears to be immunologically mediated, this study indicates that the HLA antigens do not have a major role.

Adolescent↗
PubMed1990

The immunoglobulin M heavy chain constant region gene of the channel catfish, Ictalurus punctatus: an unusual mRNA splice pattern produces the membrane form of the molecule.

The immunoglobulin (IgM) heavy chain constant region gene of the channel catfish, Ictalurus punctatus, has been cloned and characterized. The gene contains four constant region domain-encoding exons (CH1 to CH4) expressed in the secreted form of the immunoglobulin, and two exons encoding the transmembrane (TM) domain utilized in the lymphocyte membrane receptor form of the immunoglobulin. The sequence of a cDNA clone encoding the 3' region of the message for the membrane receptor form of the mu chain indicates that the TM1 exon is spliced directly to the CH3 exon, and not into a site within the CH4 exon, as occurs in the mammals, a shark and an amphibian. This unusual pattern of splicing, which produces a membrane heavy chain that is characteristically smaller than the secreted heavy chain, may be common to all teleost fish.

Amino Acid Sequence↗
PubMed1990

Mineralization of the supraspinatus tendon in dogs.

Mineralization of the supraspinatus tendon is proposed as a cause of forelimb lameness in dogs. A new radiographic position (cranioproximal-cranio-distal) is advanced to detect abnormalities of the craniomedial aspect of the proximal portion of the humerus. Four dogs had surgery to remove mineralized debris from the supraspinatus tendon insertion and have improved limb function. Two dogs were evaluated in depth, with no signs of relapse 2 to 4 years after surgery. Other dogs, without apparent forelimb lameness, have had mineralization detected by use of radiography, thus emphasizing the need for thorough forelimb evaluation before determining that the mineralization is indeed the cause of lameness.

Animals↗