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J S Rees

Publications and source records attributed to J S Rees.

64 records · Page 4Linked to original sources
PubMed1985

Incidence of Hb Barts and alpha-thalassaemia genotypes in a South African population.

The cord blood of 1,207 randomly selected neonates from the Cape Coloured population of South Africa was analysed for the presence of Hb Barts. 40 individuals (3.3%) had detectable Hb Barts levels with values ranging from 1.1 to 7.3%. Restriction enzyme analysis of DNA from subjects with Hb Barts showed that 85% of the cases studied had the genotypes -alpha 3.7/alpha alpha or -alpha 3.7/-alpha 3.7. The observed frequency of the -alpha/alpha alpha genotype was much lower than the expected frequency which suggests that this genotype is often not associated with detectable levels of Hb Barts. Mapping of the sigma-globin locus in three subjects with HbH disease revealed the presence of the--SEA/alpha-thalassaemia determinant in this population.

DNA↗
PubMed1983

The molecular basis of alpha thalassaemia in a South African population.

We have investigated the molecular basis of alpha thalassaemia in the so-called 'Cape Coloured' population of Cape Town. DNA from 17 cases was analysed by Southern blotting and hybridization with an alpha globin complementary DNA probe. Three types of alpha thalassaemia genetic determinants were detected: the 3.5 kb deletion which inactivates one alpha globin gene per chromosome (-alpha/haplotype), a much larger deletion which removes both alpha globin genes (- -/haplotype), and a non-deletion determinant which leaves both alpha globin genes intact. The interaction of these determinants with each other or with the normal chromosome (alpha alpha/) produced the phenotypes alpha thalassaemia silent carrier, alpha thalassaemia trait and Hb H disease. All cases of the -alpha/haplotype result from the rightward deletion which removes the Bgl II site between the duplicated alpha globin genes. The predominance of the -alpha/haplotype (21 out of the 28 alpha thalassaemia determinants) over the - -/haplotype is consistent with the low incidence of Hb H disease and the apparent absence of Hb Bart's hydrops fetalis in this population group.

Child↗
PubMed1972

Purification and properties of 2-furoyl-coenzyme A hydroxylase from Pseudomonas putida F2.

1. 2-Furoyl-CoA hydroxylase of Pseudomonas putida F2 has been purified 60-fold by a combination of (NH(4))(2)SO(4) fractionation, DEAE-cellulose chromatography and agarose chromatography. 2. The purified enzyme catalyses the formation of 5-hydroxy-2-furoyl-CoA, which tautomerizes to form 5-oxo-Delta(2)-dihydro-2-furoyl-CoA. 3. The enzyme has a requirement for an electron acceptor that can be satisfied by a membrane preparation from 2-furoate-grown Ps. putida F2 or by artificial electron acceptors, and so presumably the incorporated oxygen atom is derived from water rather than molecular oxygen. 4. The enzyme is a large protein with a molecular weight of 3.27x10(6) and is disrupted to form inactive subunits in the presence of 0.2% (w/v) sodium dodecyl sulphate. It has a pH optimum of 8.5-9.5, a K(m) for 2-furoyl-CoA of 20.2mum and an absorption spectrum with a trough at 265nm and a single peak at 273nm. No absorption peaks are detectable in the visible region of the spectrum. 5. The enzyme is resistant to the effects of a wide range of potential inhibitors, but is inhibited by the copper-chelating agents bathocuproin and cuprizone, though not by sodium diethyldithiocarbamate. 6. Flavins are absent and the iron content does not show a sustained increase during purification. The copper content of the protein increases in close correlation with the increase in specific activity during purification. 7. A catalytic sequence for the hydroxylation of 2-furoyl-CoA by a copper protein is proposed.

Ammonium Sulfate↗
PubMedDate not supplied

The role of drinks in tooth surface loss.

This paper outlines the current knowledge about the interaction between various groups of drinks and tooth surface loss. It begins by examining how the erosive effects of drinks are assessed in the laboratory and clinically. It then surveys the current erosive effects of various groups of drinks, including carbonated drinks, mineral waters, alcopops, ciders, beers, wine and fruit teas.

Beverages↗
PubMedDate not supplied

Update on periodontology: 2. Diagnosis in periodontology.

The second in this series of articles looks at the problems of diagnosis in periodontology. This is an area that is often neglected in the routine examination of patients, but with the introduction of systems like CPITN the examination of patients with periodontal disease is becoming easier.

Gingival Crevicular Fluid↗
PubMedDate not supplied

Finite element analysis of the stress-concentrating effect of fraenal notches in complete dentures.

Based on clinical experience and empiricism, it was postulated that fraenal notches and midline diastemas lead to fracture of complete dentures. This study used finite element stress analysis to investigate the stress-concentrating effect of a fraenal notch with and without a midline diastema. It was found that a large fraenal notch resulted in high stress levels and that these stresses were augmented more by a narrow median diastema than its wider counterpart.

Dental Stress Analysis↗