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J H Edwards

Publications and source records attributed to J H Edwards.

204 records · Page 12Linked to original sources
PubMedDate not supplied

Correlation between a DNA restriction fragment length polymorphism and C4A6 protein.

The fourth component of complement (C4) in man, is coded for by two separate but closely linked loci (C4A and C4B) within the major histocompatibility region (MHC), on the short arm of chromosome 6. Like class I and II loci of this region, the C4 genes are highly polymorphic with more than 30 alleles, including null alleles, assigned to the two loci. This extensive polymorphism, based mainly on electrophoretic mobility, provides a useful marker for studies of disease susceptibility. Several disorders, including systemic lupus erythematosus and type I diabetes, show associations with C4 phenotypes. We have used the technique of Southern with a C4 specific probe to examine the genomic DNA of individuals typed for C4 by protein electrophoresis. We have identified 10.7 and 3.8 kilobase (kb) BglII restriction fragments in each of 9 unrelated individuals with a C4A6 allele, and in none of 22 unrelated individuals in whom this allele was not expressed. This clear correlation of restriction fragment length polymorphism with C4 phenotype provides a precise basis for analysis of C4 polymorphism. It is likely to be of value in clinical investigations of autoimmune disease.

Complement C4↗
PubMedDate not supplied

0.6 T MR imaging of the cervical spine: multislice and multiecho techniques.

During a 6 month period, 50 patients with signs and symptoms referable to the cervical spine were studied with a 0.6 T superconducting magnetic resonance (MR) imaging unit. The last 23 of these 50 patients were studied with combined multislice and multiecho techniques. In 38 of the 50 patients, abnormalities were demonstrated on MR images. Intramedullary lesions included syringomyelia (three cases), primary tumors (two), metastatic neoplasm (one), cord atrophy secondary to trauma (one), and multiple sclerosis (one). Intradural, extramedullary lesions included two neurofibromas and two Chiari malformations. The rest of the lesions were extradural: degenerative changes (10), spinal stenosis with cord compression (five), disk degeneration and/or herniation (five), postoperative changes (four), metastases to bone/epidural disease (three), and neurofibromatosis (one). Two patients had more than one abnormality. The MR findings were compared with available routine radiographs, computed tomographic (CT) scans with and without metrizamide, and myelograms. MR imaging was consistently better than routine CT scanning in the detection of lesions of the spinal cord and in directly imaging the effects on the spinal cord of extrinsic abnormalities such as spinal stenosis. Metrizamide-enhanced CT scanning detected all cases of syringomyelia, but it involved an invasive procedure. Myelography alone was slightly less sensitive and considerably less specific than MR in detecting intramedullary lesions and in distinguishing cord neoplasms from syringomyelia. Multislice, multiecho techniques with up to 240 msec echo times (TEs) were particularly helpful in the detection and characterization of extradural processes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗