Biomedical subjects
Publications and source records attributed to P J Turner.
We report 12 cases of transient osteoporosis in 10 patients. The presenting symptoms, diagnostic investigations and management are considered here as well as a discussion on the aetiology and the pathology. Arthroscopic surgery was carried out in some of the patients to exclude intraarticular pathology. Resolution of symptoms occurred in all patients within 6 months and the MRI findings returned to normal.
AZD2563, a new oxazolidinone targeted at Gram-positive bacteria, was evaluated and compared with linezolid and other agents against 802 aerobic bacterial isolates for spectrum of activity, bactericidal activity, and the effect of miscellaneous factors upon activity in vitro. At a concentration of 2 mg/L, AZD2563 inhibited 98% of all Gram-positive bacteria tested (100% at 4 mg/L), including susceptible and resistant isolates of Staphylococcus aureus, coagulase-negative staphylococci, Enterococcus spp., Streptococcus pneumoniae, other Streptococcus spp. and Corynebacterium spp. Conversely, all Enterobacteriaceae and non-fermenting Gram-negative bacteria had MICs > 128 mg/L, and only a few Haemophilus or Moraxella spp. had MICs < 8 mg/L. By conventional laboratory definition, AZD2563 and linezolid were bacteriostatic against staphylococci and enterococci, with variable bactericidal activity against Strep. pneumoniae. The in-vitro activity of AZD2563 was essentially unaffected by altering pH, inoculum size, the type of testing medium, or the inclusion of human serum up to 25% v/v.
There has long been a discrepancy between microwave conductivity measurements in high temperature superconductors and the conductivity spectrum expected in the simplest models for impurity scattering in a d-wave superconductor. Here we present a new type of broadband measurement of microwave surface resistance that finally shows some of the spectral features expected for a d(x2-y2) pairing state. Cusp-shaped conductivity spectra, consistent with weak impurity scattering of nodal quasiparticles, were obtained in the 0.6-21 GHz frequency range in highly ordered crystals of YBa2Cu3O6.50 and YBa2Cu3O6.99.
In vitro susceptibilities to meropenem and comparators of Acinetobacter strains isolated from serious infections in 37 European hospital centers participating in the Meropenem Yearly Susceptibility Test Information Collection (MYSTIC) Program (1997-2000) were tested. There were 635 Acinetobacter strains collected: 490 A. baumannii; 51 A. calcoaceticus var. lwoffii; and 94 other Acinetobacter strains. Overall, meropenem and imipenem were the most effective agents tested. Resistance to the antimicrobials was: 14%, meropenem; 16%, imipenem; 39%, piperacillin-tazobactam; 41%, tobramycin; 45%, ceftazidime; and 53%, ciprofloxacin. Thus, the carbapenems have useful activity against Acinetobacter spp. and represent a viable choice for treating infections caused by these organisms.
Resistance patterns that are currently problematic in Europe can vary greatly within the same species over time, among various patient populations and among geographic regions on the same continent. The results from the Meropenem Yearly Susceptibility Test Information Collection (MYSTIC) Program, which monitors carbapenem resistance rates in institutions using meropenem, were used to determine resistance differences among Proteus mirabilis. MIC results from 688 P. mirabilis strains were classified into 4 patient care groups: ICU (n=426), neutropenia patients (NP; n=145), general wards (n=97) and cystic fibrosis patients (CF; n=20). A total of 40 centers from 12 European countries have participated since 1997, divided into 3 geographic regions (East, North, South). All testing was performed by NCCLS reference methods and interpretive criteria, including screening of extended-spectrum beta-lactamase (ESBL) phenotypes. Over the monitored interval the resistance rates varied for each agent without a clear trend toward a greater rate. Rank order of susceptibility was: meropenem (99%) > piperacillin/tazobactam (TAZ; 96%) > cefepime (95%) > ceftazidime (CAZ; 94%) > imipenem (IPM; 92%). Ciprofloxacin (CIP) was the least active agent tested (MIC90 4 microg/ml; 86% susceptible). Unexpectedly, 3.6% of P. mirabilis were imipenem-resistant (MIC, > or = 16 microg/ml). Greater rates of resistance were found for strains from NP and CF patients, and from eastern or southern European sites, usually associated with epidemic clusters. Generally susceptible species such as P. mirabilis have recently emerged as therapeutic problems in European medical centers following mutations that compromise CIP, CAZ and aminoglycoside use. Imipenem also showed decreased susceptibility of greater than 7% compared to less than 1% for meropenem. Continued surveillance by the MYSTIC Program appears to be a prudent practice to focus effective empiric treatment regimens.
Fixed nitrogen (N) often limits the growth of organisms in terrestrial and aquatic biomes, and N availability has been important in controlling the CO2 balance of modern and ancient oceans. The fixation of atmospheric dinitrogen gas (N2) to ammonia is catalysed by nitrogenase and provides a fixed N for N-limited environments. The filamentous cyanobacterium Trichodesmium has been assumed to be the predominant oceanic N2-fixing microorganism since the discovery of N2 fixation in Trichodesmium in 1961 (ref. 6). Attention has recently focused on oceanic N2 fixation because nitrogen availability is generally limiting in many oceans, and attempts to constrain the global atmosphere-ocean fluxes of CO2 are based on basin-scale N balances. Biogeochemical studies and models have suggested that total N2-fixation rates may be substantially greater than previously believed but cannot be reconciled with observed Trichodesmium abundances. It is curious that there are so few known N2-fixing microorganisms in oligotrophic oceans when it is clearly ecologically advantageous. Here we show that there are unicellular cyanobacteria in the open ocean that are expressing nitrogenase, and are abundant enough to potentially have a significant role in N dynamics.
The Meropenem Yearly Susceptibility Test Information Collection (MYSTIC) Program is a longitudinal global antimicrobial surveillance study that compares the activity of meropenem and comparator antimicrobial agents against pathogens isolated from intensive care, neutropenic or cystic fibrosis patients, and general wards. Data from the different European MYSTIC Program units (1997-2000) showed that the most prevalent isolates tested overall were methicillin-susceptible Staphylococcus aureus (MSSA; in accordance with study design methicillin-resistant S. aureus was not tested), Pseudomonas aeruginosa and Escherichia coli. In all the unit types, E. coli (approximately 20% having an extended spectrum beta-lactamase phenotype) and MSSA were highly susceptible to meropenem (97-99% susceptibility). Isolates of MSSA showed lower levels of susceptibility to ciprofloxacin (61-77% susceptibility) in both cystic fibrosis and neutropenia patients, and particularly high levels of resistance to ceftazidime (38% susceptibility) in cystic fibrosis units. Ciprofloxacin (54% susceptibility) and gentamicin (46% susceptibility) demonstrated low levels of activity against P. aeruginosa (frequently encountered in cystic fibrosis units). Meropenem and piperacillin/tazobactam were the most active agents against P. aeruginosa in all the unit types. Carbapenems and piperacillin/tazobactam have sustained > 90% susceptibility rates overall against the most frequently isolated pathogens. The analysis of specific units that house patients with a high-risk of contracting antimicrobial-resistant pathogens remains very important for the optimal selection of empiric regimens.
OBJECTIVE: A method of cephalometric analysis is described in which cephalometric x-rays were scanned using a flat-bed scanner and transparency hood. Then the image was displayed on a computer monitor for point identification and subsequent cephalometric analysis using dedicated software. The reproducibility of point identification using this method was compared with two other, commonly used, methods. MATERIAL AND METHODS: The study material comprised 25 lateral skull x-rays taken as part of routine orthodontic assessment. Repeat cephalometric point identification was carried out on each x-ray using 3 methods: 1. On-screen digitization of the scanned bitmap image (Screenceph method). 2. Tracing followed by digitization of the identified points and 3. Direct digitization. RESULTS: For the 8 angular and 4 linear cephalometric measurements examined the Screenceph method compared favourably with the two conventional methods. The median difference between methods was 0.5 degrees and 0.2 mm. Using constructed Cartesian axes to examine the x, y discrepancy between repeat measurements and comparing Screenceph to tracing followed by digitization, there were significant differences in 3 instances at the 5% level and 2 instances at the 1% level. These differences represented median scores of 0.14 to 0.32 mm greater for Screenceph. Comparing Screenceph to direct digitization 15 significant differences out of the 28 measurements were noted: six at the 5% level and 9 at the 1% level. The actual difference in median scores ranged from 0.2 mm to 0.53 mm. CONCLUSION: The results demonstrated that Screenceph is sufficiently accurate to use in a clinical setting but is not yet sufficiently exact for use in research projects owing to hardware limitations.
This article defines and describes the process of backing up data files, which should be undertaken by anyone who routinely uses a computer. The important points to be considered when developing a backup strategy are explained and a résumé given of the backup devices currently available.
In order to access the Internet it is necessary to open an account with an Internet Service Provider. This article describes the typical services provided by these companies so that the new subscriber will be in a better position to make an informed choice.
This article discusses the use of speech recognition software by means of reviewing two leading packages. Both programs require considerable training before they can be used effectively, but are then able to convert continuous speech into text with varying degrees of success.
1. The aim of this study was to investigate the role of kinins in the development of nasal hyperresponsiveness induced by platelet activating factor (PAF) in normal human subjects. 2. Intranasal administration of PAF, 60 micrograms, induced an increased responsiveness to histamine, 200 micrograms per nostril, 6 h later. This effect was abolished by pretreatment with the bradykinin B2 receptor antagonists icatibant and [1-adamantaneacetyl-D-Arg0,Hyp3,beta-(2-thienyl)-Al a5,8,D-Phe7]-bradykinin ([Ad]-BK), both at 200 micrograms, every 2 h following PAF administration. 3. In a separate experiment, utilizing the same protocol, nasal lavage was used to measure the release of mediators into the nasal cavity following treatment with PAF. PAF increased the levels of eosinophil cationic protein (ECP) and kinin detected in the lavage samples, compared with a saline control. The levels of these mediators were reduced by pretreatment with either icatibant or [Ad]-BK. 4. Administration of lyso-PAF, 60 micrograms intranasally, did not cause a rise in kinin or ECP levels in nasal lavage fluid. 5. Exogenous bradykinin, 500 micrograms, or a saline control, applied topically to the nasal mucosa every 30 min for 2 h, failed to cause hyperresponsiveness to histamine. 6. We conclude that bradykinin itself does not cause hyperresponsiveness, but is involved in the hyperresponsiveness induced by PAF in the human nasal airway.
1. The effects of inhibitors of nitric oxide synthase (NOS) on the responsiveness of the human nasal airway were investigated, by measuring the nasal response to histamine and bradykinin. 2. Repeated intranasal administration of N(G)-nitro-L-arginine methyl ester (L-NAME) or N(G)-monomethyl-L-arginine (L-NMMA), 1 micromol per nostril every 30 min for 6 h, increased the nasal obstruction induced by histamine, 50 - 500 microg, and bradykinin, 200 microg per nostril. A single administration of L-NAME, 1 micromol per nostril did not induce hyperresponsiveness to histamine. 3. Pretreatment with L-arginine, 30 micromol, abolished the hyperresponsiveness to histamine caused by L-NAME, 1 micromol. Pretreatment with N(G)-nitro-D-arginine methyl ester (D-NAME), 1 micromol, did not induce hyperresponsiveness to histamine. 4. Repeated administration of L-NAME, 1 micromol, caused a significant reduction in the amount of nitric oxide measured in the nasal cavity. 5. Neither L-NMMA, 1 micromol, nor L-arginine, 30 micromol, altered the nasal hyperresponsiveness induced by platelet activating factor (PAF), 60 microg. PAF did not alter the levels of nitric oxide in the nasal cavity. 6. The results suggest that inhibition of nitric oxide synthase induces a hyperresponsiveness in the human nasal airway, and that this occurs by a mechanism different from that involved in PAF-induced hyperresponsiveness.
The Meropenem Yearly Susceptibility Test Information Collection (MYSTIC) is a global, multicentre surveillance study that compares the activity of meropenem in centres that are prescribers with that of imipenem, ceftazidime, piperacillin/tazobactam, ciprofloxacin and gentamicin. Of the 46 centres (intensive care units, cystic fibrosis units, neutropenia units and general wards) contributing to this study, 29 were in Europe, 14 in the Americas and three in the Middle East and Asia. The results for the most common isolates obtained in the first year of the study from these three regions show that meropenem has a broad spectrum of activity and potency in these centres, with 89% of the 6890 strains tested having an MIC < or = 4 mg/L. The overall susceptibility was lower for the comparator antibiotics. There was evidence in all regions of strains producing beta-lactamases and other resistance mechanisms against the other beta-lactams tested, fluoroquinolones and aminoglycosides. Future years' results from this surveillance study will show whether meropenem will continue to exhibit such activity.
The primary objective of the MYSTIC study is to monitor the performance of meropenem over a period of at least 3 years during which this carbapenem is prescribed in different hospital units thus allowing profiles to be established within individual hospitals. Monitoring is being carried out by assessing the antibiotic susceptibility of bacterial pathogens isolated from patients with a predominate problem of intraabdominal infections (IAI) and/or lower respiratory tract infections (LRTI), treated in specialist centres (haematology wards, the Intensive Care Unit [ICU], cystic fibrosis units) and non-specialised centres. Samples will be collected over each year and tested against meropenem and a set of comparators. The data obtained from the first year of the study (1997) come from 33 centres spread mainly throughout Europe but also in Israel and Mexico. The results shows that meropenem retains its broad spectrum and potency whilst there is evidence that the activity of comparator antibiotics is being eroded by a variety of resistance mechanisms. Data from subsequent years of the programme will determine whether these trends continue and will allow a series of individual centre profiles to be compiled and presented.
Allergic rhinitis is a condition which affects over 15% of the population in the United Kingdom. The pathological process involves two stages: nasal inflammation, and the development of nasal airway hyperresponsiveness (AHR) to allergen and a number of other stimuli. This results in the amplification of any subsequent allergic reaction, contributing to the chronic allergic state. A number of different hypotheses have been proposed to explain the underlying mechanism of AHR, including a role for eosinophil-derived proteins, free radicals and neuropeptides. While there may be a number of independent pathways which can result in AHR, evidence obtained from both animal models and in vivo experiments in humans indicate that some mediators may interact with one another, resulting in AHR. Further research into these interactions may open new avenues for the pharmacological treatment of chronic allergic rhinitis, and possibly other allergic airway diseases.
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This article examines the specialist software that is commercially available to assist the running of a dental practice. Generically termed 'practice management systems' (PMSs), these programs are designed to help perform many of the clerical, administrative and accounting tasks traditionally carried out manually, in a shorter time and with greater accuracy. PMSs have benefited considerably from advances in computer technology, particularly the increased speed of processors and graphic displays, to the point that they have become a viable alternative to an appointments diary and clinical records.