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Biomedical subjects

P J Turner

Publications and source records attributed to P J Turner.

At least 19 recordsLinked to original sources
PubMed2000

Involvement of kinins in hyperresponsiveness induced by platelet activating factor in the human nasal airway.

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.

Adamantane↗
PubMed2000

Induction by inhibitors of nitric oxide synthase of hyperresponsiveness 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.

Adult↗
PubMed2000

MYSTIC (Meropenem Yearly Susceptibility Test Information Collection): a global overview.

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.

Anti-Bacterial Agents↗
PubMed1999

The MYSTIC (meropenem yearly susceptibility test information collection) programme.

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.

Bacteria↗
PubMed1999

Hyperresponsiveness in the human nasal airway: new targets for the treatment of allergic airway disease.

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.

Animals↗
PubMed1998

Basic computing for dental practitioners: 5. Practice management systems.

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.

Appointments and Schedules↗
PubMed1998

Basic computing for dental practitioners: 6. Multimedia and communication.

This final article in the series on computing for dental practitioners examines multimedia and the Internet. Multimedia is one area where the greatest advances have been made in recent years; almost all PCs marketed today have multimedia capabilities and more and more software is being written with multimedia attributes.

Computer Graphics↗
PubMed1998

Basic computing for dental practitioners: 1. The principles of computers and computing.

The purpose of this series of six articles is to introduce the interested general dental practitioner to computers and computing, to remove much of the mystery surrounding computers and to explain the technology in straightforward terms. The first two articles will concentrate on the basic principles; later papers will discuss the most commonly used software, practice management systems and multimedia.

Computer User Training↗
PubMed1996

Combined orthodontic and restorative management of a case of bilateral ectopic canines and resorbed central incisors.

A case is reported in which two ectopic maxillary permanent canine teeth bypassed the lateral incisors and caused extensive resorption to both maxillary central incisor teeth. Management involved positioning the canine teeth into the central incisor region and placing porcelain veneers on these teeth. The orthodontic and restorative implications of the treatment are discussed.

Child↗
PubMed1996

Successful bonding in orthodontics: 1.

Since it was first described in 1955, direct bonding of orthodontic attachments to the teeth has become routine in fixed appliance therapy. The technique used is deceptively simple: meticulous attention to detail and a thorough understanding of the factors involved are needed to ensure a successful outcome.

Acid Etching, Dental↗
PubMed1995

A compilation of meropenem tissue distribution data.

Meropenem body fluid and tissue concentration data from both published studies and samples obtained during efficacy evaluation have been compiled and presented according to a consistent format to facilitate comparison. The concentration data have been compared with the mode MIC data available for the pathogens isolated during the clinical evaluation of meropenem. These data support the widespread and rapid penetration of meropenem into the interstitial fluid of those tissues not protected by a tight epithelial barrier. Furthermore, they suggest that the proposed dosages of meropenem 500 mg or 1 g tds would provide an adequate duration of cover at tissue sites for the treatment of a range of commonly occurring pathogens. A higher dosage of 40 mg/kg or 2 g in adults given tds would be recommended for meningitis based on the penetration of meropenem into CSF. Overall, the tissue and body fluid data presented confirm the expectation, based on the plasma concentrations and theoretical arguments, that meropenem is rapidly and readily distributed into the interstitial fluid, thereby producing concentrations in tissues likely to be clinically effective. This is consistent with the available clinical data on the therapeutic efficacy of meropenem.

Carbapenems↗
PubMed1995

Laboratory data which differentiate meropenem and imipenem.

Meropenem and imipenem are carbapenems which are distinguishable from all other currently available beta-lactam antibiotics by breadth of antibacterial spectrum and stability to beta-lactamases, but can be differentiated one from another. Meropenem is relatively stable to human renal dehydropeptidase-I (DHP-I); it does not require to be co-administered with cilastatin and consequently, unlike imipenem, will be administered as a single agent. In vitro both meropenem and imipenem are active against almost all clinically important aerobic and anaerobic bacteria. Differences in potency are seen but few may be of clinical significance: imipenem is more active against enterococci and meropenem is more active against Pseudomonas aeruginosa, Pseudomonas cepacia, Haemophilus influenzae and Proteus, Morganella and Providencia species. The primary target of imipenem is PBP2 in P. aeruginosa whilst meropenem has high affinity for both PBP2 and 3; this may contribute to greater potency against this organism. Laboratory evaluations predict that meropenem will not be seizurogenic, which combined with activity against likely pathogens, identified its potential for the treatment of bacterial meningitis. This has been investigated in a guinea-pig model in which meropenem exhibited potent activity against the common meningeal pathogens and also infections caused by penicillin-resistant Streptococcus pneumoniae or Listeria monocytogenes. Clinical experience will determine the significance of these differences.

Animals↗
PubMed1994

Prone oblique positioning for computed tomographic arthrography of the shoulder.

Computed tomographic arthrography (CTA) of the shoulder is currently the best investigation of the unstable shoulder. 47 patients had CTA in the prone oblique position to assess its ability to demonstrate both anterior and posterior capsular mechanisms simultaneously. The first five patients were also scanned supine oblique to allow direct comparison with the prone oblique position. All studies were reviewed retrospectively by three musculoskeletal radiologists with regard to how well the relevant structures were demonstrated. In the prone oblique position, the anterior capsule was well shown in 98%, anterior labrum 98%, posterior capsule 91%, posterior labrum 89%, subscapularis tendon 98%, biceps tendon 100% and biceps tendon proximal insertion 78%. In 86% of cases both anterior and posterior structures were well seen simultaneously. In the five cases that also had supine imaging the prone oblique images were superior. The cause of poor demonstration of structures was invariably insufficient intraarticular air. It is concluded that the prone oblique is an excellent technique for CTA of the shoulder and should become the standard position for assessing shoulder instability.

Adolescent↗