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Biomedical subjects

D J Hughes

Publications and source records attributed to D J Hughes.

18 recordsLinked to original sources
PubMed2004

Measurement of carbon dioxide levels during use of ELSA and the effect of venting on these levels.

DESIGN: A prospective, objective assessment of ELSA use, in order to determine whether venting of the ELSA influences carbon dioxide (CO2) levels. PRIMARY ENDPOINT: Inspired and expired CO2 levels. SETTING: On board RFA ARGUS during Operation TELIC. METHODS: 10 volunteers had a baseline of inspired and expired CO2 levels taken. These levels were measured at one minute intervals during use of an ELSA in 3 conditions--sitting, jogging and jogging with venting. RESULTS: There was no difference in expired CO2 levels between baseline and use of ELSA whilst sitting. Periodic venting of the ELSA made no difference to inspired and expired CO2 levels. CONCLUSIONS: Venting of the ELSA during use makes no difference to CO2 levels whether inspired or expired. Therefore, venting is unnecessary and potentially wastes vital time during escape from a smoke-filled compartment and adds additional stress to the escapee.

Adult↗
PubMed1998

Structural polymorphism in a tubercidin analogue of the DNA double helix.

A high-angle X-ray fibre diffraction study of a tubercidin analogue of the poly[d(A-T)].poly[d(A-T)] DNA double helix has been carried out using station 7.2 at the Daresbury Laboratory synchrotron radiation source. The polymer has been studied for a wide range of salt strengths and hydration conditions and exhibits conformational polymorphism that is quite distinct from that observed for the unmodified polymer. The replacement of deoxyadenosine by deoxytubercidin in the polynucleotide causes only slight alterations to the structure of A-DNA, but significantly alters the structure of the B conformation. Additionally, the modified polymer does not, in any conditions yet identified, adopt the D conformation. In conditions which would normally favour the D conformation of poly[d(A-T)].poly[d(A-T)], the modified polymer adopts an unusual conformation which is designated here as the K conformation. These observations are important for an understanding of major groove interactions involved in the stabilisation of particular DNA conformations and also more generally for an insight into the pharmacological activity of tubercidin which following its incorporation into nucleic acids may cause stereochemical distortions of the DNA double helix.

DNA↗
PubMed1996

Time-Resolved Simultaneous SAXS/WAXS of the Drawing of Polyethylene at the Daresbury SRS.

A system has been developed which represents a significant advance in the quality and extent of small- and wide-angle X-ray scattering data (SAXS and WAXS) that can be recorded simultaneously with strain data during the drawing and annealing of polymer materials. WAXS data are recorded using a Photonic Science charge-coupled-device area detector and SAXS data using a gas-filled multiwire area detector. Strain data, for the region of the specimen from which the SAXS/WAXS data are collected, are calculated from an accurately synchronized continuously recorded video image of the specimen. The system allows X-ray and video image data to be collected as a series of frames with essentially no ;dead-time' between frames. The data are fully two-dimensional and can be collected for a wide range of d spacings. The use of this system to investigate the stress-induced orientation and phase changes during the drawing of a range of grades of commercially available polyethylene is described.

Journal Article↗
PubMed1996

Mutation characterization of CFTR gene in 206 Northern Irish CF families: thirty mutations, including two novel, account for approximately 94% of CF chromosomes.

A variety of mutation detection techniques, including restriction endonuclease digestion, allele specific oligonucleotides, and automated fluorescent sequencing, were used in the identification of 15 CFTR mutations representing 86.7% of CF chromosomes in 206 Northern Irish cystic fibrosis (CF) families. A systematic analysis of the 27 exons and intron/exon boundaries of the CFTR gene was performed using denaturing gradient gel electrophoresis (DGGE) in an attempt to characterise the 55 unknown CF mutations in 51 patients. Twenty different mutations were detected by DGGE on 30 chromosomes accounting for a further 7.3% of CF alleles. Fifteen of these mutations had not previously been found in Northern Ireland, and two are novel, M1I(G > T) and V562L. In total, 30 CFTR mutations account for 93.9% of the 412 Northern Irish CF chromosomes tested. The three major CF mutations in Northern Ireland are delta F508, G551D, and R117H with respective frequencies of 68.0%, 5.1%, and 4.1%. The efficacy of the DGGE technique was proven by the detection of 77 out of 77 control variants from all the CFTR exons. DGGE is a highly efficient and sensitive method for mutation screening especially in large genes where the mutation spectrum is known to be heterogeneous.

Alleles↗
PubMed1993

2-Hydroxymethyl-3,4-dihydroxy-6-methyl-pyrrolidine (6-deoxy-DMDP), an alkaloid beta-mannosidase inhibitor from seeds of Angylocalyx pynaertii.

A polyhydroxy alkaloid has been isolated from the seeds of the African legume Angylocalyx pynaertii and identified as a 2-hydroxymethyl-3,4-dihydroxy-5-methylpyrrolidine by ms and 1H- and 13C-nmr spectroscopy. The absolute stereochemistry was established, by a stereochemically unambiguous synthesis from diacetone glucose, as 2,5-imino-1,2,5-trideoxy-D-mannitol, which may also be regarded as 2R,5R-dihydroxymethyl-3R,4R-dihydroxypyrrolidine (DMDP) [2] in which a hydroxymethyl group is deoxygenated, i.e., 6-deoxy-DMDP [1]. Whereas the structurally related polyhydroxypyrrolidine alkaloids which have previously been discovered are inhibitors of alpha- and beta-glucosidase, 6-deoxy-DMDP is unique in inhibiting beta-mannosidase. In addition to this novel alkaloid and 2-hydroxymethyl-3,4-dihydroxypyrrolidine [3], previously shown to be present in several Angylocalyx species, the known piperidine alkaloids deoxymannojirimycin [4] and fagomine [5] were identified for the first time as constituents of An. pynaertii seeds.

Alkaloids↗
PubMed1993

Antibacterial activity of multilayer silver-copper surface films on catheter material.

The antimicrobial activity of Ag, Cu, and layered Ag-Cu surface films, sputter-coated onto several types of catheter material, against clinical isolates of Staphylococcus epidermidis and Staphylococcus aureus was evaluated. When 20 microL of a suspension of S. epidermidis or S. aureus (2.68 x 10(6) colony-forming units/mL) was applied onto Ag-Cu- or Cu-coated butyl rubber, bacterial numbers were greatly reduced within 10 h, and eliminated within 24 h. In contrast, antibacterial activity was significantly less on uncoated or Ag-coated surfaces. Ag-Cu- or Cu-coated silicon rubber, polyvinylchloride, and teflon were even more effective than Ag-Cu- or Cu-coated butyl rubber. Ag-Cu layered surface films also showed antibacterial activity against Pseudomonas aeruginosa biofilm formation. Multiple metal surface film combinations show great promise in lowering the incidence of device-associated nosocomial infections.

Catheterization↗
PubMed1989

Frameworks for midwifery care in Great Britain: an exploration of quality assurance.

In order to design a quality assurance tool for midwifery it was necessary to assess current frameworks and standards for practice. With that aim a questionnaire was sent to all midwifery managers in the UK. The findings showed that 'Planned Individualised Care' is the favoured framework for midwifery practice and that the use of nursing models (or adapted versions of these) and midwifery models is widespread but not prevalent. Documentation for midwifery care is not always in accordance with the favoured framework for care as reported. The standards articulated in the three 'Maternity Care in Action' reports are those aspired to by most maternity units. Methods of assessing the quality of maternity care are many and varied but show a clear trend towards giving precedence to gauging client satisfaction with the service.

Midwifery↗
PubMed1979

Bovine ocular squamous-cell carcinoma: lymphocyte response to phytohaemagglutinin and tumour antigen.

The presence of ocular squamous-cell carcinomas in cattle was associated with significantly lower blastogenic response of peripheral-blood cultures to PHA than that of age-matched control cattle. The difference in blastogenic response was more marked when the external diameter of the tumour exceeded 2 cm. Cattle with aquamous-cell carcinomas had cell-mediated immunity against tumour extracts, as measured by the leucocyte adherence inhibition (LAI) microassay. The LAI reaction against tumour extracts was directly proportional to the general level of cell-mediated immunity as demonstrated by the lymphoproliferative response to PHA.

Animals↗
PubMed1979

Rapid assay for repair of damage induced by ultraviolet light in bovine lymphocytes.

Bovine peripheral blood lymphocytes exhibit a peak of deoxyribonucleic acid (DNA) repair, measured after exposure of cells to ultraviolet light, three to four days after phytohaemagglutinin addition to diluted blood cultures. This peak of DNA repair is induced coincidentally with that of DNA replication. DNA repair is determined in the presence of hydroxyurea which inhibits DNA replication. This assay provides a rapid screening method for deficits in DNA repair synthesis in cattle.

Animals↗