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Biomedical subjects

G J Price

Publications and source records attributed to G J Price.

28 records · Page 2Linked to original sources
PubMed1988

Multiple interactions of lysine-128 of Escherichia coli glutamate dehydrogenase revealed by site-directed mutagenesis studies.

A highly conserved lysine at position 128 of Escherichia coli glutamate dehydrogenase (GDH) has been altered by site-directed mutagenesis of the gdhA gene. Chemical modification studies have previously shown the importance of this residue for catalytic activity. We report the properties of mutants in which lysine-128 has been changed to histidine (K128H) or arginine (K128R). Both mutants have substantially reduced catalytic centre activities and raised pH optima for activity. K128H also has increased relative activity with amino acid substrates other than glutamate, especially L-norvaline. These differences, together with alterations in Km values, Kd values for NADPH and Ki values for D-glutamate, imply that lysine-128 is intimately involved in either direct or indirect interactions with all the substrates and also in catalysis. These multiple interactions of lysine-128 explain the diverse effects of chemical modifications of the corresponding lysine in homologous GHDs. In contrast, lysine-27, another highly reactive residue in bovine GDH, is not conserved in all of the sequenced NADP-specific GDHs and is therefore not likely to be involved in catalysis.

Amino Acid Sequence↗
PubMed1987

Isolation and characterization of a vinculin cDNA from chick-embryo fibroblasts.

A chick-embryo fibroblast lambda gt11 cDNA library was screened with affinity-purified antibodies to chick gizzard vinculin. One recombinant was purified to homogeneity and the fusion protein expressed in Escherichia coli strain C600. The fusion protein was unstable, but polypeptides that reacted with vinculin antibodies, but not non-immune immunoglobulin, were detected by Western blotting. The recombinant contained a single EcoRI fragment of 2891 bp with a single open reading frame. The deduced protein sequence could be aligned with that of six CNBr-cleavage peptides and two tryptic peptides derived from chicken gizzard vinculin. AUG-247 has tentatively been identified as the initiation codon, as it is contained within the consensus sequence for initiation sites of higher eukaryotes. The cDNA lacks 3' sequence and encodes 74% of the vinculin sequence, presuming the molecular mass of vinculin to be 130,000 Da. Analysis of the deduced sequence showed no homologies with other protein sequences, but it does display a triple internal repeat of 112 amino acid residues covering residues 259-589. The sequences surrounding the seven tyrosine residues in the available sequence were aligned with the tyrosine autophosphorylation consensus sequence found in protein tyrosine kinases. Tyr-822 showed a good match to this consensus, and may represent one of the two major sites of tyrosine phosphorylation by pp60v-sre. Northern blots showed that the 2.89 kb vinculin cDNA hybridized to one size of mRNA (approx. 7 kb) in chick-embryo fibroblasts, chick smooth muscle and chick skeletal muscle. Southern blots revealed multiple hybridizing bands in genomic DNA.

Amino Acid Sequence↗
PubMed1987

Abdominal aortic aneurysm causing duodenal obstruction.

Two cases of abdominal aortic aneurysm presenting with duodenal obstruction following truncal vagotomy and pyloroplasty are described. Barium examination revealed the site and cause of obstruction in both. In one case the aneurysm was successfully resected.

Aged↗
PubMed1987

A combined approach to the assessment of neurological dysphagia.

The dysphagia encountered by patients with neurological disorders can be both distressing and life threatening because of the associated problems of aspiration. Decisions regarding management are often difficult because the exact nature of the underlying disorder varies from patient to patient and is frequently complex. A new approach to the assessment and evaluation of acquired neurological dysphagia is presented. Management of the first 50 patients assessed by this method is described. The advantages of a joint dysphagia clinic comprising neurology, speech therapy, ENT and radiology departments are discussed.

Combined Modality Therapy↗
PubMed1987

Peroneal tendon injury associated with calcaneal fractures: CT findings.

Injury to the peroneal tendons is one of the major long-term complications of intraarticular calcaneal fractures and heretofore has been difficult to diagnose by noninvasive radiography. Retrospective review of CT scans of 24 intraarticular calcaneal fractures, obtained shortly after injury, identified 22 cases (92%) of acute peroneal tendon abnormalities. In most of these cases, multiple findings were present. These included lateral displacement in 14 (58%) of 24, impingement by bony fragments in eight (33%), subluxation or dislocation in six (25%), soft-tissue masses around the tendons representing hematomas or early scar tissue in five (21%), and entrapment of the tendons in three (13%). In 10 cases with long-term follow-up, impingement on the tendons by bony fragments correlated well with the subsequent development of peroneal tenosynovitis, while hematoma around the tendons or lateral displacement of the tendons was clinically insignificant. Thus, CT in the immediate postfracture period, can be used to detect and categorize acute peroneal tendon injuries as well as possibly to predict the likelihood and nature of subsequent development of peroneal tenosynovitis.

Calcaneus↗
PubMed1986

Complete plantar foot coverage with the free neurosensory radial forearm flap.

Resurfacing the sole of the foot is a unique and challenging problem. Many methods have been advocated in search of an ideal solution. When the entire surface requires reconstruction, alternatives have been limited, and their results have often been less than satisfactory. Free-flap transfer allows a single-stage reconstruction from a variety of donor sites. This report of a free neurosensory radial forearm flap to cover a complete plantar weight-bearing surface is an additional choice for reconstruction. This flap has the potential for sensory reinnervation by the medial antebrachial cutaneous nerve and when elevated without its fascia can provide improved adherency.

Accidents, Occupational↗
PubMedDate not supplied

Newborn screening for congenital hypothyroidism, Victoria, Australia, 1977-1997. Part 1: The screening programme, demography, baseline perinatal data and diagnostic classification.

Clinical, demographic and laboratory data from infants with congenital hypothyroidism (CH) born in the Australian state of Victoria from the commencement of neonatal screening in mid-1977 until December 1988 are reported. These provide a baseline for a 12-year prospective longitudinal study on physical and neuro-psychological outcome until mid-1997, the subject of a second paper. Infants with CH were detected using a primary TT4 screening test. Demographic data were collected prospectively using a clinical assessment protocol. Nearly all affected infants underwent 99mTc pertechnetate scanning at the initial assessment to determine the underlying aetiology of their hypothyroidism. 704,723 infants were screened and 199 with permanent primary hypothyroidism (one in 3,541) were identified. The most common aetiologies were thyroid ectopia (46%), thyroid aplasia (33%), and 'dyshormonogenesis' (11%). The clinical abnormalities classically described in CH were more evident in infants with aplasia, and the striking female preponderance in infants with thyroid dysplasia (syn. dysgenesis) was confirmed. Other features included increased frequencies of 'dyshormonogenesis' in infants of parents of Middle-Eastern origin and of labour induction in infants with dysplasia. A closed posterior fontanelle was not found in any infant with thyroid aplasia.

Age Determination by Skeleton↗
PubMedDate not supplied

Newborn screening for congenital hypothyroidism, Victoria, Australia, 1977-1997. Part 2: Treatment, progress and outcome.

A controlled longitudinal prospective study is reported of physical and neuropsychological progress up to 12 years in 152 children with congenital hypothyroidism (CH), detected by newborn screening in the Australian state of Victoria and born between the onset of screening in mid-1977 and December 1988. Linear growth of the CH children was normal. Throughout they were slightly heavier and the median head circumference was slightly larger compared with reference data. Those with thyroid aplasia required a marginally larger dose of thyroxine to achieve euthyroidism. Assessment of cognitive outcome in the children with permanent primary CH revealed the mean scores at 2, 5 and 8 years to be from 8.5 (p<0.001) to 10.2 (p<0.001) points lower than in a group of 60 euthyroid controls. However, there was large overlap and, of the affected children, only 10.1% at 2 years, 3.9% at 5 years and 6.8% at 8 years fell more than 2 SD below the means of the euthyroid controls. On univariate analysis, variables shown to have significant correlation with cognitive outcome at 8 years in the CH children were newborn activity, baseline TT4 and FTI, initial T4 dosage, socio-economic classification, maternal age, maternal education and presence of a serious accompanying disorder. On multiple regression analysis, significant variables were baseline bone age, maternal age and education, and presence of a serious accompanying disorder. No single thyroidal or extra-thyroidal variable could be identified to account for the discrepancy between the children with CH and the controls.

Age Determination by Skeleton↗