What is this thing called EBM?
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Evidence-Based Medicine↗
Biomedical subjects
K H Pwee
Publications and source records attributed to K H Pwee.
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Databases, Bibliographic↗
Influenza in Singapore: assessing the burden of illness in the community.
INTRODUCTION: Influenza infection has significant morbidity and mortality. The social and economic costs from work absence in the working population and from hospitalisations in the elderly are considerable. Meta-analyses of cohort and randomised controlled studies indicate that influenza vaccination is effective in preventing respiratory illness, hospitalization, pneumonia and death in 50% to 68% of cases. In Singapore, data on the disease burden from influenza are sparse and no official recommendation on influenza vaccination exists. METHOD: We estimated the disease burden of influenza-like illness (ILI), influenza infection in the general adult population, and hospitalisations and deaths from pneumonia and influenza, from routine official and published sources, and hoc community sample surveys, national virological surveillance, hospitalization and mortality data. RESULTS: In a resident population of 3 million people, there were 4.2 million cases of ILI in a typical non-epidemic year, 3.5 million visits to the doctor and 2.1 million days of work absence due to ILI. Data from the National Influenza Surveillance Programme indicated that about 15% of patients with ILI were positive for influenza isolates. We therefore estimated 630,000 cases of influenza virus infection cases a year, giving rise to 520,000 sick visits and 315,000 days of sick absence from work. About 4200 elderly (65+) persons were hospitalised for pneumonia and influenza, resulting in about 1450 deaths every year. The literature suggests a vaccine efficacy of about 50% of preventing influenza and its complications, including hospitalizations and deaths. This indicates that at least 315,000 cases of influenza virus infection, 258,000 sick visits, and 157,000 lost days from work in the whole population, and 2100 hospitalisations and 600 deaths from pneumonia in the elderly are potentially preventable by vaccination each year. CONCLUSION: Influenza poses a considerable burden of illness in the community and the potential benefits from influenza vaccination are substantial.
Adult↗
DNA binding mediated by the wheat HMGa protein: a novel instance of selectivity against alternating GC sequence.
The high-mobility-group (HMG) chromosomal protein wheat HMGa was purified to homogeneity and tested for its binding characteristics to double-stranded DNA. Wheat HMGa was able to bind to P268, an A/T-rich fragment derived from the pea plastocyanin gene promoter, producing a small mobility shift in gel retardation assays where the bound complex was sensitive to addition of proteinase K but resistant to heat treatment of the protein, consistent with the identity of wheat HMGa as a putative HMG-I/Y protein. Gel retardation assays and southwestern hybridization analysis revealed that wheat HMGa could selectively interact with the DNA polynucleotides poly(dA).poly(dT), poly(dAdT).poly(dAdT), and poly(dG).poly(dC), but not with poly(dGdC).poly(dGdC). Surface plasmon resonance analysis determined the kinetic and affinity constants of sensor chip-immobilized wheat HMGa for double-stranded DNA 10-mers, revealing a good affinity of the protein for various dinucleotide combinations, except that of alternating GC sequence. Thus contrary to prior reports of a selectivity of wheat HMGa for A/T-rich DNA, the protein appears to be able to interact with sequences containing guanine and cytosine residues as well, except where G/C residues alternate directly in the primary sequence.
Base Sequence↗
High mobility group proteins HMG-1 and HMG-I/Y bind to a positive regulatory region of the pea plastocyanin gene promoter.
A 268 bp region (P268) of the pea plastocyanin gene promoter responsible for high-level expression has been shown to interact with the high mobility group proteins HMG-1 and HMG-I/Y isolated from pea shoot chromatin. cDNAs encoding an HMG-1 protein of 154 amino acid residues containing a single HMG-box and a C-terminal acidic tail and an HMG-I/Y-like protein of 197 amino acid residues containing four AT-hooks have been isolated and expressed in Escherichia coli to provide large amounts of full-length proteins. DNase I footprinting identified eight binding sites for HMG-I/Y and six binding sites for HMG-1 in P268. Inhibition of binding by the antibiotic distamycin, which binds in the minor groove of A/T-rich DNA, revealed that HMG-I/Y binding was 400-fold more sensitive than HMG-1 binding. Binding-site selection from a pool of random oligonucleotides indicated that HMG-I/Y binds to oligonucleotides containing stretches of five or more A/T bp and HMG-1 binds preferentially to oligonucleotides enriched in dinucleotides such as TpT and TpG.
Amino Acid Sequence↗
HMG protein binding to an A/T-rich positive regulatory region of the pea plastocyanin gene promoter.
Gel retardation assays using pea nuclear extracts have detected specific binding to regions of the promoter of the pea plastocyanin gene (petE). Several complexes which differ in sensitivity to competition with unlabelled promoter fragments and various DNA alternating copolymers, to heat treatment and to digestion with proteinase K have been detected. A protein factor, PCF1, forming one of these complexes was heat-stable and most sensitive to competition with poly(dAdT).poly(dAdT) compared to other alternating copolymers. DNase I footprinting assays showed that tracts of A/T-rich sequence within the -444 to -177 positive regulatory region of the petE promoter were protected in the presence of the pea nuclear extract. The factor PCF1 copurified with a high-mobility-group (HMG) protein preparation from pea chromatin. DNase I footprinting with the HMG protein preparation demonstrated that similar tracts of A/T-rich sequences within the promoter were protected. Southwestern-blot analysis of pea HMG proteins purified by gel filtration through Superose 12 detected a single DNA-binding species of 21 kDa. The properties of the factor PCF1 suggest that it is likely to be an HMG I protein.
Base Composition↗
The pea plastocyanin promoter directs cell-specific but not full light-regulated expression in transgenic tobacco plants.
A series of 5' deletions of the pea plastocyanin gene (petE) promoter fused to the beta-glucuronidase (GUS) reporter gene has been examined for expression in transgenic tobacco plants. Strong positive and negative cis-elements which modulate quantitative expression of the transgene in the light and the dark have been detected within the petE promoter. Disruption of a negative regulatory element at -784 bp produced the strongest photosynthesis-gene promoter so far described. Histochemical analysis demonstrated that all petE-GUS constructs directed expression in chloroplast-containing cells, and that a region from -176 bp to +4 bp from the translation start site was sufficient for such cell-specific expression. The petE-promoter fusions were expressed at high levels in etiolated transgenic tobacco seedlings but there was no marked induction of GUS activity in the light. The endogenous tobacco plastocyanin genes and the complete pea plastocyanin gene in transgenic tobacco plants were also expressed in the dark, but showed a three- to sevenfold increase in the light. This indicates a requirement for sequences 3' to the promoter for the full light response of the petE gene.
Base Sequence↗