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Biomedical subjects

J B Wright

Publications and source records attributed to J B Wright.

At least 19 recordsLinked to original sources
PubMed2001

A survey of trainee obstetricians preferences for childbirth.

OBJECTIVE: To determine trainee obstetricians personal preferences regarding mode and place of delivery given various scenarios. STUDY DESIGN: An anonymous nationwide postal survey of 365 specialist registrars. RESULTS: The response rate was 76%. About 2.5% preferred a home birth. And 16% of men and 15% of women opted for elective cesarean section (CS). When faced with a proposed trial of instrumental delivery in theatre, 60% accepted and a further 12% accepted only if they could choose the obstetrician performing the delivery. Regarding a breech presentation at term, 78% would accept external cephalic version (ECV). CONCLUSIONS: The percentage of obstetricians who preferred vaginal delivery and ECV were considerably higher than previously reported, and there were no significant gender differences. This study shows a more balanced attitude from obstetricians and refutes the previously held view that they necessarily advocate high levels of intervention for themselves.

Attitude of Health Personnel↗
PubMed2000

Healing of porcine donor sites covered with silver-coated dressings.

OBJECTIVE: To compare rates of healing of donor sites in pigs between those dressed with silver-coated dressings and those dressed with petrolatum-impregnated absorbent gauze. DESIGN: Open study with each animal acting as its own control. SETTING: University research facility, Canada. ANIMALS: 6 young specific-pathogen-free domestic pigs. INTERVENTIONS: A total of 72 wounds about 1 cm x 2 cm x 0.4 mm were made in rows of eight on each pig with a dermatome. They were divided into three groups of 24, and dressed with petrolatum gauze, or silver-coated dressings moistened with sterile water either once only or daily for 10 days. All dressings were secured in place with an elastic bandage. MAIN OUTCOME MEASURES: Erythema, infection, epidermal migration, and healing. RESULTS: Wounds dressed with moistened silver-coated dressings re-epithelialised significantly more quickly. This resulted in complete re-epithelialisation within 70% of the time taken by those wounds dressed with petrolatum gauze. CONCLUSION: Silver-coated dressings provide a moist environment for the healing wound combined with an effective antimicrobial agent, and this significantly accelerates healing compared with wounds dressed with traditional petrolatum gauze dressings.

Animals↗
PubMed2000

Molecular and cell biology of skin wound healing in a pig model.

To define the pattern of change at the molecular and cellular levels during the healing of excisional skin wounds in the skeletally immature pig, mRNA levels for relevant molecules were assessed by semiquantitative RT-PCR using porcine specific primer sets and RNA isolated from normal skin and samples at various time post-wounding. Analysis of cellular change was assessed by DNA quantification and histology of tissue sections. The results demonstrated that the changes in the pattern of RNA and DNA content of the scar tissue were consistent with the observed increasing cellularity. The mRNA levels for collagen I, III, HSP47, IL-1, TGF-beta, MMP-1, -2 and -9, TIMP-1, -2, and-4, PAI-1, versican were significantly elevated during healing; levels for biglycan and fibromodulin were not significantly altered; and the mRNA levels for TIMP-3 were depressed. These findings suggest that skin wound healing is a series of complex matrix-cell interactions that involve cellular migration and inflammation, followed by proliferation of fibroblasts with new collagen synthesis, and lastly tissue remodeling of the scar.

Animals↗
PubMed1999

Analysis of VX on soil particles using ion trap secondary ion mass spectrometry.

The direct detection of the nerve agent VX (methylphosphonothioic acid, S-[2-[bis(1-methylethyl)amino]ethyl] O-ethyl ester) on milligram quantities of soil particles has been achieved using ion trap secondary ion mass spectrometry (IT-SIMS). VX is highly adsorptive toward a wide variety of surfaces; this attribute makes detection using gas-phase approaches difficult but renders the compound very amenable to surface detection. An ion trap mass spectrometer, modified to perform SIMS, was employed in the present study. A primary ion beam (ReO4-) was fired on axis through the ion trap, where it impacted the soil particle samples. [VX + H]+, [VX + H]+ fragment ions, and ions from the chemical background were sputtered into the gas-phase environment of the ion trap, where they were either scanned out or isolated and fragmented (MS2). At a surface concentration of 0.4 monolayer, intact [VX + H]+, and its fragment ions, were readily observable above background. However, at lower concentrations, the secondary ion signal from VX became obscured by ions derived from the chemical background on the surface of the soil particles. MS2 analysis using the ion trap was employed to improve detection of lower concentrations of VX: detection of the 34S isotopic ion of [VX + H]+, present at a surface concentration of approximately 0.002 monolayer, was accomplished. The study afforded the opportunity to investigate the fragmentation chemistry of VX. Semiempirical calculations suggest strongly that the molecule is protonated at the N atom. Deuterium labeling showed that formation of the base peak ion (C2H4)N(i-C3H7)2+ involves transfer of the amino proton to the phosphonothioate moiety prior to, or concurrent with, C-S bond cleavage. To manage the risk associated with working with the compound, the vacuum unit of the IT-SIMS was located in a hood, connected by cables to the externally located electronics and computer.

Chemical Warfare Agents↗
PubMed1999

Fragmentation of an alkali metal-attached peptide probed by collision-induced dissociation fourier transform mass spectrometry and computational methodology.

Collision-induced dissociation of metal-cationized N-CBZ-Gly-Pro-Gly-Pro-Ala was studied by Fourier transform mass spectrometry. Lithium-, sodium-, potassium- and rubidium-cationized peptide species were generated by matrix-assisted laser desorption/ionization (MALDI) using 2,5-dihydroxybenzoic acid as matrix, together with appropriate metal salts. The experimental mass spectrometric results were interpreted with the aid of Monte Carlo conformational searches using the Amber(*) force field, together with ab initio molecular orbital calculations with Gaussian-94 for the singly lithium- and potassium-cationized peptides. It is concluded that metal coordination plays a key role in guiding the gas-phase fragmentation of the cationized peptide. In contrast to lithium and sodium, potassium and rubidium apparently do not coordinate to the C-terminal carbonyl. When the peptide is cationized with the two smaller alkali metals, losses corresponding to alanine and CBZ are observed, while the coordination of potassium and rubidium results in only CBZ loss upon dissociation.

Amino Acid Sequence↗
PubMed1999

Efficacy of topical silver against fungal burn wound pathogens.

BACKGROUND: Fungal infections of burn wounds have become an important cause of burn-associated morbidity and mortality. The nature of fungal infections dictates aggressive treatment to minimize the morbidity associated with these infections. Persons with large total body surface area burns are particularly susceptible to fungal infections and are treated in such a manner as to minimize their risk of infection. METHODS: This study examined the in vitro fungicidal efficacy of a variety of different topical agents. By placing fungal inocula in contact with mafenide acetate, silver nitrate, silver sulfadiazine, and a nanocrystalline silver-coated dressing, we determined the kill kinetics of these topical agents against a spectrum of common burn wound fungal pathogens. RESULTS: The topical antimicrobials that were tested demonstrated varying degrees of efficacy against these pathogens. CONCLUSION: The nanocrystalline silver-based dressing provided the fastest and broadest-spectrum fungicidal activity and may make it a good candidate for use to minimize the potential of fungal infection, thereby reducing complications that delay wound healing.

Antifungal Agents↗
PubMed1998

Wound management in an era of increasing bacterial antibiotic resistance: a role for topical silver treatment.

BACKGROUND: Antibiotic-resistant bacteria represent an increasing concern in wound infections. Wound colonization with these organisms normally results in aggressive management of the wound complicated by a greatly limited choice of therapeutic antibiotics. Silver and other noble metals are recognized as potential allies in combating these organisms in wounds. METHODS: Three types of topical silver applications were tested to determine their bactericidal efficacies against clinical isolates of antibiotic-resistant organisms. The silver-based applications represent 3 methods of applying silver to wounds: as a liquid (silver nitrate), incorporated in a cream (silver sulfadiazine) and as a dressing coating (silver-coated dressings). The reduction in the viable bacterial population recovered from test articles after exposure to silver provided a comparative measure of the bactericidal efficacies of these silver applications. RESULTS: All of the products demonstrated an ability to reduce the number of viable bacteria. However, the methods varied in their efficacy against antibiotic-resistant bacteria, with the silver-coated dressing being the most efficacious and silver nitrate the least efficacious. CONCLUSIONS: Silver was demonstrated to be effective at killing the antibiotic-resistant strains tested. The silver-coated dressing was particularly rapid at killing the tested bacteria and was effective against a broader range of bacteria. Silver may be a useful prophylactic or therapeutic agent for the prevention of wound colonization by organisms that impede healing, including antibiotic-resistant bacteria.

Administration, Cutaneous↗
PubMed1996

Gravitropism in roots of intermediate-starch mutants of Arabidopsis.

Gravitropism was studied in roots of wild type (WT) Arabidopsis thaliana (L.) Heynh. (strain Wassilewskija) and three starch-deficient mutants that were generated by T-DNA insertional mutagenesis. One of these mutants was starchless while the other two were intermediate mutants, which had 51% and 60%, respectively, of the WT amount of starch as determined by light and electron microscopy. The four parameters used to assay gravitropism were: orientation during vertical growth, time course of curvature, induction, and intermittent stimulation experiments. WT roots were much more responsive to gravity than were roots of the starchless mutant, and the intermediate starch mutants exhibited an intermediate graviresponse. Our data suggest that lowered starch content in the mutants primarily affects gravitropism rather than differential growth because both phototropic curvature and growth rates were approximately equal among all four genotypes. Since responses of intermediate-starch mutants were closer to the WT response than to the starchless mutant, it appears that 51-60% of the WT level of starch is near the threshold amount needed for full gravitropic sensitivity. While other interpretations are possible, the data are consistent with the starch statolith hypothesis for gravity perception in that the degree of graviresponsiveness is proportional to the total mass of plastids per cell.

Arabidopsis↗
PubMed1995

Wild water rapid burns.

Swimming pool water slides are becoming increasingly long and adventurous. This case report and survey suggest that they may carry with them a notable risk of friction burns.

Adult↗
PubMed1994

Performance of four different indirect enzyme-linked immunosorbent assays (ELISAs) to detect specific IgG, IgA, and IgM in Legionnaires' disease.

Currently recommended methods in Legionnaires' disease serology are based upon crude whole-cell antigenic preparations. To investigate whether purified antigens would perform better in a given diagnostic test for antibodies against Legionella pneumophila, we compared the performance of three antigenic preparations of L. pneumophila serogroup 1 consisting of outer membrane protein (OMP), flagellin (FLA), and lipopolysaccharide (LPS) to a sonic extract (SON) in indirect immunosorbent assay (ELISA) measuring both IgG, IgA, and IgM. The reactivity of sera from 20 patients with culture-verified Legionnaires' disease and sera from 12 patients with pneumonia and a diagnostic rise in titre by a microagglutination test (MA) was studied. Our results indicated that the SON IgA assay was the most sensitive test in both groups of patients. The LPS IgG and IgM assays, however, were the most specific tests, closely followed by the corresponding SON tests. By combining two individual assays, a maximum nosographic sensitivity of 85% could be obtained. Whereas no benefit of using purified outer membrane protein or flagella instead of a sonic extract in the indirect ELISAs was found, the LPS antigen provided a sensitive and specific alternative to the sonic extract.

Antibodies, Bacterial↗
PubMed1993

Mania following sleep deprivation.

A first episode of mania is described in a previously healthy man who was partially sleep deprived for four nights. The sleep deprivation preceded the psychosis. During the psychotic episode he believed that he was the Messiah. This case is discussed in the light of reports exploring the relationship between psychosis and sleep deprivation.

Adult↗
PubMed1992

Demonstration of the intracellular production of tissue-destructive protease by Legionella pneumophila multiplying within guinea-pig and human alveolar macrophages.

The major extracellular enzyme of Legionella pneumophila, a metalloprotease, has been proposed as a pathogenic factor in Legionnaires' disease due to its cytotoxic, tissue-destructive, and phagocyte-inhibitory properties. The relevance of these activities depends on the production of the protease during infection, i.e. by L. pneumophila multiplying intracellularly. In this study, L. pneumophila was demonstrated to produce protease in guinea-pig and human alveolar macrophages infected in vitro. After 24 h infection, approximately 0.1 to 0.2 micrograms of protease per 10(6) bacteria was measured by ELISA in culture supernatants and lysates of the infected cells, whereas no protease could be detected immediately after infection. Immunogold labelling using anti-protease antibody showed the enzyme to be located within phagosomes and distributed throughout the macrophages. Recent observations have shown that this protease could modify host defence mechanisms through inhibition of bacterial killing by neutrophils and monocytes. The intracellular production of the enzyme in infected macrophages demonstrated here further supports a role for the protease in the pathogenesis of Legionnaires' disease.

Animals↗
PubMed1991

Decreased biocide susceptibility of adherent Legionella pneumophila.

In a study of the in vitro effectiveness of biocides against Legionella pneumophila, some aspects of the cooling tower environment were replicated in the laboratory, paying particular attention to water hardness and pH. Pieces of Douglas fir and polyvinyl chloride were colonized in a recirculating system and the comparative efficacy of two biocides (Bronopol and Kathon) against the sessile and planktonic populations was examined. While the biocides were relatively effective against the planktonic L. pneumophila population over a short period of time (minimum 9-12 h), substantially longer periods of time (maximum greater than 48 h) were required to reduce the number of cultivable bacteria to below detectable levels in the adherent population. The results indicate that failure to monitor the sessile population of L. pneumophila in laboratory studies of biocides may result in the use of incorrect dosages and/or contact times in field trials with apparently reduced in situ efficacy.

Anti-Bacterial Agents↗