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Biomedical subjects

D S Gill

Publications and source records attributed to D S Gill.

87 records · Page 5Linked to original sources
PubMed1985

Serum immunoreactive erythropoietin and erythropoiesis in protein-energy malnutrition.

Immunoreactive erythropoietin was estimated in the sera of 23 Nigerian children with protein-energy malnutrition (PEM) and 14 healthy Nigerian children of similar age attending a well baby clinic. The geometric mean estimate for this parameter was 262 mIU/ml (observed range 39-1340 mIU/ml; 95% confidence range 25-1738 mIU/ml) in the children with PEM and 80 mIU/ml (observed range 43-257 mIU/ml; 95% confidence range 27-241 mIU/ml) in the health children. Erythropoietin levels were above the 95% confidence range for the healthy children in 14 of the cases of PEM. There was a statistically significant inverse correlation between the haemoglobin levels of the children with PEM and the logarithm of immunoreactive serum erythropoietin estimates (r = -0.73; P less than 0.001). By contrast, statistically significant correlations were not found between the logarithm of erythropoietin estimates and either the percentage of erythroblasts in the marrow, the M/E ratio or the logarithm of the absolute blood reticulocyte count. These data suggest that there is no abnormality of erythropoietin production in PEM and that the anaemia seen in this condition results from an impairment of erythropoiesis. A stepwise multiple regression analysis revealed a positive correlation between the logarithm of the erythropoietin level and the logarithm of the concentration of circulating neutrophil metamyelocytes plus myelocytes and we speculate on the aetiology of this finding.

Child, Preschool↗
PubMed1985

Changes in the uptake of 57Co-cyanocobalamin during dimethylsulphoxide-induced differentiation of HL60 cells to neutrophils.

The uptake of serum-bound 57Co-cyanocobalamin by uninduced and dimethylsulphoxide-induced HL60 cells has been studied. The data indicate that during the maturation of promyelocytes to neutrophil granulocytes, there is a progressive and marked reduction in (a) the number of surface receptors for the transcobalamin II-cobalamin complex (TCII-Cbl) per cell up to the metamyelocyte stage and (b) the amount of TCII-Cbl entering a cell, through the entire maturation pathway. The maturation of promyelocytes to neutrophil granulocytes was also accompanied by a marked reduction in intracellular vitamin B12 content. These observations help in explaining some features of granulocytopoiesis in cobalamin deficiency.

Biological Transport↗
PubMed1985

Limited value of serum ferritin in evaluating iron status in children with protein-energy malnutrition.

26 of 46 Nigerian children with protein-energy malnutrition (PEM) had elevated S-Ferritin levels; the geometric mean value in the entire group of children with PEM was 146 micrograms/l and the observed range 11-7000 micrograms/l. There was no statistically significant correlation between the logarithm of the S-Ferritin level and the amount of stainable iron in marrow fragments (r = 0.23; p greater than 0.2). A stepwise multiple linear regression analysis in which the logarithm of the S-Ferritin level was used as the dependent variable and a total of 17 clinical, biochemical and haematological parameters were used as the independent variables showed that 34.8% of the variability in S-Ferritin could be accounted for by variations in the percentage of lymphocytes in the bone marrow. We speculate that the latter parameter may be an index of previous infection and that the elevated S-Ferritin levels may, therefore, be at least partly caused by infections. Increased serum aspartate transaminase activities were also encountered in PEM, suggesting that hepatocellular damage may contribute to the high S-Ferritin levels in this condition. Our data indicate that S-Ferritin has a limited value as an indicator of iron status in subjects with PEM, presumably because of the frequency of infections and of hepatocellular damage in such subjects.

Body Temperature↗
PubMed1985

Vesicular stomatitis virus NS proteins: structural similarity without extensive sequence homology.

The complete nucleotide sequence of the NS mRNA of vesicular stomatitis virus (New Jersey serotype) was established from two cDNA clones spanning the entire coding region of the mRNA. The gene is 856 nucleotides long and can code for a polypeptide of 274 amino acids. Comparison with the nucleotide sequence of the NS gene of the Indiana serotype revealed only 41% sequence homology. The deduced amino acid sequences of the NS proteins were only 32% homologous, with no identical stretches of more than five amino acids. However, at the C-terminal domain there was a conserved region of 21 amino acids with greater than 90% homology. Surprisingly, relative hydropathicity plots also demonstrated the presence of a large number of hydrophilic amino acids sequestered similarly over the N-terminal half of the protein. In addition, the total number of serine and threonine residues, presumptive phosphorylation sites, was similar and included seven serine and three threonine residues located at identical positions. It appears that during divergent evolution of these two vesicular stomatitis virus serotypes from a common ancestor, considerable mutation occurred in the main body of the gene but the overall structure of the protein was retained. The function of the NS protein in relation to the evolution of the two viruses is discussed.

Amino Acid Sequence↗
PubMed1984

Complete nucleotide sequence of the mRNA coding for the N protein of vesicular stomatitis virus (New Jersey serotype).

The nucleotide sequence of the mRNA encoding the nucleocapsid protein of the New Jersey serotype (Ogden strain) of vesicular stomatitis virus (VSV) was determined from two overlapping cDNA clones spanning almost entirely the coding region of the mRNA. The 5'-terminal noncoding sequence present in the mRNA but not in the cDNA clones was determined from a primer extended to the 5' terminus of the mRNA. The mRNA is 1329 nucleotides long (excluding polyadenylic acid) and encodes a protein of 422 amino acids. The nucleotide sequence was compared with the previously determined nucleotide sequence of the nucleocapsid protein of the Indiana serotype. An overall identity of 67.7% was found between the two serotypes. The only place where insertions and/or deletions have occurred during the evolution of the two viral genes from their presumed common ancestor is in the untranslated region. The nonidentical nucleotides are distributed throughout the length of the mRNA although not in an entirely random manner. The predicted amino acid sequence demonstrates that both proteins are initiated from the initiator codon located at the same distance from the 5' end (nucleotides 14 to 16) and contain the same number of amino acids. An overall identity of more than 80% of the amino acid sequence was observed between the two proteins when conservative replacements of amino acids were considered.

Amino Acid Sequence↗
PubMedDate not supplied

Differences in sequence-specific expression of two anti-arsonate Fabs in E. coli.

Monoclonal antibodies are potentially useful therapeutic agents and can now be produced in hosts such as bacteria. However, it has been found that bacterial expression of some antibody-combining site fragments is greatly diminished. We compared two homologous anti-arsonate antibodies, 36-65 and 36-71, to address the question of why the former but not the latter expresses well as Fab in E. coli. These antibodies are both derived from the same variable region germline genes but differ in affinity due to somatic mutations present in 36-71. To investigate the poor expression of 36-71 Fab, we examined several factors, such as cellular toxicity, induction with isopropylthio-beta-D-galactoside, and growth of transformed bacteria at lower temperatures (30 degrees C), as well as the possibility of E. coli strain-related expression of Fab. However, none of these factors made a significant difference to Fab expression. We next localized a significant portion of the defect in Fab expression to the heavy chain by swapping the heavy and light chains from the two antibodies to construct hybrid Fabs. We used site-directed mutagenesis to engineer amino acids into the variable regions of antibody 36-71, to reproduce those found in 36-65 which is expressed well in E. coli. The defect in expression is due to residues located in the complementarity-determining regions, as mutations of heavy chain framework residues to those present in 36-65 do not enhance expression of 36-71 Fab in E. coli.

Amino Acid Sequence↗
PubMedDate not supplied

Treatment planning for the loss of first permanent molars.

During the mixed-dentition stage of dental development, dentists may encounter patients with first permanent molars considered to have a poor long-term prognosis. In this situation, extraction of the tooth and space closure or use of the extraction space for future orthodontic treatment should be considered. The aim of this article is to give guidelines about treatment planning for patients who have first molars with a poor prognosis during the mixed-dentition stage.

Age Factors↗