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Biomedical subjects

C Price

Publications and source records attributed to C Price.

At least 19 recordsLinked to original sources
PubMed2006

Strength of cancellous bone trabecular tissue from normal, ovariectomized and drug-treated rats over the course of ageing.

Hormone therapy (HT) drugs and bisphosphonates prevent osteoporosis by inhibiting osteoclastic bone resorption. However, the effects of osteoporosis and anti-resorptive drugs on the mechanical behavior of the bone tissue constituting individual trabeculae have not yet been quantified. In this study, we test the hypothesis that the mechanical properties of bone trabecular tissue will differ for normal, ovariectomized and drug-treated rat bones over the course of ageing. Microtensile testing is carried on individual trabeculae from tibial bone of ovariectomized (OVX) rats, OVX rats treated with tibolone and placebo-treated controls. The method developed minimizes errors due to misalignment and stress concentrations at the grips. The local mineralization of single trabeculae is compared using micro-CT images calibrated for bone mineral content assessment. Our results indicate that ovariectomy in rats increases the stiffness, yield strength, yield strain and ultimate stress of the mineralized tissue constituting trabecular bone relative to normal; we found significant differences (P < 0.05) at 14, 34 and 54 weeks of treatment. These increases are complemented by a significant increase in the mineral content at the tissue level, although overall bone mineral density and mass are reduced. With drug treatment, the properties remain at, or slightly below, the placebo-treated controls levels for 54 weeks. The higher bone strength in the OVX group may cause the trabecular architecture to adapt as seen during osteopenia/osteoporosis, or alternately it may compensate for loss of trabecular architecture. These findings suggest that, in addition to the effects of osteoporosis and subsequent treatment on bone architecture, there are also more subtle processes ongoing to alter bone strength at the tissue level.

Aging↗
PubMed2006

Transfusion-related acute lung injury in the paediatric patient: Two case reports and a review of the literature.

Transfusion-related acute lung injury (TRALI) is increasingly recognized as a major complication of transfusion therapy; it was the leading cause of transfusion-related fatalities in the United States in 2003. Most cases of TRALI that have been reported are in adult patients. We present two cases of TRALI that occurred in children and review the existing literature of paediatric TRALI. The paediatric TRALI case reports highlight two laboratory findings that can help in the diagnosis of TRALI: transient leucopenia and an elevated pulmonary oedema fluid/plasma protein ratio. These two simple diagnostic tests can help rule out other diagnoses and add confidence to the clinical diagnosis of TRALI. Finally, our first case also highlights the potential danger of directed maternal blood donations, which may increase the risk of paediatric TRALI.

Adolescent↗
PubMed2005

A multicentre randomized controlled trial of epidural corticosteroid injections for sciatica: the WEST study.

OBJECTIVE: To determine the effectiveness and predictors of response to lumbar epidural corticosteroid injections (ESI) in patients with sciatica. We performed a 12-month, multicentre, double-blind, randomized, placebo-controlled, parallel-group trial in four secondary pain-care clinics in the Wessex Region. METHODS: Two hundred and twenty-eight patients with a clinical diagnosis of unilateral sciatica of 1-18 months' duration were randomized to either three lumbar ESIs of triamcinolone acetonide or interligamentous saline injections at intervals of 3 weeks. The main outcome measure was the Oswestry low back pain disability questionnaire (ODQ). RESULTS: At 3 weeks, the ESI group demonstrated a transient benefit over the placebo group (patients achieving a 75% improvement in ODQ, 12.5 vs 3.7%; number needed to treat, 11.4). No benefit was demonstrated from 6 to 52 weeks. ESIs did not improve physical function, hasten return to work or reduce the need for surgery. There was no benefit of repeated ESIs over single injection. No clinical predictors of response were found. At the end of the study the majority of patients still had significant pain and disability regardless of intervention. CONCLUSIONS: In this pragmatic study, ESIs offered transient benefit in symptoms at 3 weeks in patients with sciatica, but no sustained benefits in terms of pain, function or need for surgery. Sciatica is a chronic condition requiring a multidisciplinary approach. To fully investigate the value of ESIs, they need to be evaluated as part of a multidisciplinary approach.

Adolescent↗
PubMed2005

Brain abnormalities underlying altered activation in dyslexia: a voxel based morphometry study.

Voxel-based morphometry was used to assess the consistency among functional imaging and brain morphometry data in developmental dyslexia. Subjects, from three different cultural contexts (UK, France and Italy), were the same as those described in a previous PET activation paper, which revealed a common pattern of reduced activation during reading tasks in the left temporal and occipital lobes. We provide evidence that altered activation observed within the reading system is associated with altered density of grey and white matter of specific brain regions, such as the left middle and inferior temporal gyri and the left arcuate fasciculus. This supports the view that dyslexia is associated with both local grey matter dysfunction and with altered connectivity among phonological/reading areas. The differences were replicable across samples confirming that the neurological disorder underlying dyslexia is the same across the cultures investigated in the study.

Adult↗
PubMed2005

The genome of the social amoeba Dictyostelium discoideum.

The social amoebae are exceptional in their ability to alternate between unicellular and multicellular forms. Here we describe the genome of the best-studied member of this group, Dictyostelium discoideum. The gene-dense chromosomes of this organism encode approximately 12,500 predicted proteins, a high proportion of which have long, repetitive amino acid tracts. There are many genes for polyketide synthases and ABC transporters, suggesting an extensive secondary metabolism for producing and exporting small molecules. The genome is rich in complex repeats, one class of which is clustered and may serve as centromeres. Partial copies of the extrachromosomal ribosomal DNA (rDNA) element are found at the ends of each chromosome, suggesting a novel telomere structure and the use of a common mechanism to maintain both the rDNA and chromosomal termini. A proteome-based phylogeny shows that the amoebozoa diverged from the animal-fungal lineage after the plant-animal split, but Dictyostelium seems to have retained more of the diversity of the ancestral genome than have plants, animals or fungi.

ATP-Binding Cassette Transporters↗
PubMed2005

Cost-effectiveness and safety of epidural steroids in the management of sciatica.

OBJECTIVES: To investigate the clinical effectiveness of epidural steroid injections (ESIs) in the treatment of sciatica with an adequately powered study and to identify potential predictors of response to ESIs. Also, to investigate the safety and cost-effectiveness of lumbar ESIs in patients with sciatica. DESIGN: A pragmatic, prospective, multicentre, double-blind, randomised, placebo-controlled trial with 12-month follow-up was performed. Patients were stratified according to acute (<4 months since onset) versus chronic (4-18 months) presentation. All analyses were performed on an intention-to-treat basis with last observation carried forward used to impute missing data. SETTING: Rheumatology, orthopaedic and pain clinics in four participating centres: three district hospitals and one teaching hospital in the south of England. PARTICIPANTS: Total of 228 patients listed for ESI with clinically diagnosed unilateral sciatica, aged between 18 and 70 years, who had a duration of symptoms between 4 weeks and 18 months. INTERVENTIONS: Patients received up to three injections of epidural steroid and local anaesthetic (active), or an injection of normal saline into the interspinous ligament (placebo). MAIN OUTCOME MEASURES: The primary outcome measure was the Oswestry Disability Questionnaire (ODQ); measures of pain relief and psychological and physical function were collected. Health economic data on return to work, analgesia use and other interventions were also measured. Quality-adjusted life-years (QALYs) were calculated using the SF-6D, calculated from the Short Form (SF-36). Costs per patient were derived from figures supplied by the centres' finance departments and a costings exercise performed as part of the study. A cost-utility analysis was performed using the SF-36 to calculate costs per QALY. RESULTS: ESI led to a transient benefit in ODQ and pain relief, compared with placebo at 3 weeks (p = 0.017, number needed to treat = 11.4). There was no benefit over placebo between weeks 6 and 52. Using incremental QALYs, this equates to and additional 2.2 days of full health. Acute sciatica seemed to respond no differently to chronic sciatica. There were no significant differences in any other indices, including objective tests of function, return to work or need for surgery at any time-points. There were no clinical predictors of response, although the trial lacked sufficient power to be confident of this. Adverse events were uncommon, with no difference between groups. Costs per QALY to providers under the trial protocol were 44,701 pounds sterling. Costs to the purchaser per QALY were 354,171 pounds sterling. If only one ESI was provided then costs per QALY fell to 25,745 pounds sterling to the provider and 167,145 pounds sterling to the purchaser. ESIs thus failed the QALY threshold recommended by the National Institute for Health and Clinical Excellence (NICE). CONCLUSIONS: Although ESIs appear relatively safe, it was found that they confer only transient benefit in symptoms and self-reported function in a small group of patients with sciatica at substantial costs. ESIs do not provide good value for money if NICE recommendations are followed. Additional research is suggested into the epidemiology of radicular pain, producing a register of all ESIs, possible subgroups who may benefit from ESIs, the use of radiological imaging, optimal early interventions, analgesic agents and nerve root injections, the use of cognitive behavioural therapy in rehabilitation, improved methods of assessment, a comparative cost-utility analysis between various treatment strategies, and methods to reduce the effect of scarring and inflammation.

Acute Disease↗
PubMed2004

Introduction to the DAPPLE Air Pollution Project.

The Dispersion of Air Pollution and its Penetration into the Local Environment (DAPPLE) project brings together a multidisciplinary research group that is undertaking field measurements, wind tunnel modelling and computer simulations in order to provide better understanding of the physical processes affecting street and neighbourhood-scale flow of air, traffic and people, and their corresponding interactions with the dispersion of pollutants at street canyon intersections. The street canyon intersection is of interest as it provides the basic case study to demonstrate most of the factors that will apply in a wide range of urban situations. The aims of this paper are to introduce the background of the DAPPLE project, the study design and methodology for data collection, some preliminary results from the first field campaign in central London (28 April-24 May 2003) and the future for this work. Updated information and contact details are available on the web site at http://www.dapple.org.uk.

Air Pollution↗
PubMed2004

Genome sequence of the enterobacterial phytopathogen Erwinia carotovora subsp. atroseptica and characterization of virulence factors.

The bacterial family Enterobacteriaceae is notable for its well studied human pathogens, including Salmonella, Yersinia, Shigella, and Escherichia spp. However, it also contains several plant pathogens. We report the genome sequence of a plant pathogenic enterobacterium, Erwinia carotovora subsp. atroseptica (Eca) strain SCRI1043, the causative agent of soft rot and blackleg potato diseases. Approximately 33% of Eca genes are not shared with sequenced enterobacterial human pathogens, including some predicted to facilitate unexpected metabolic traits, such as nitrogen fixation and opine catabolism. This proportion of genes also contains an overrepresentation of pathogenicity determinants, including possible horizontally acquired gene clusters for putative type IV secretion and polyketide phytotoxin synthesis. To investigate whether these gene clusters play a role in the disease process, an arrayed set of insertional mutants was generated, and mutations were identified. Plant bioassays showed that these mutants were significantly reduced in virulence, demonstrating both the presence of novel pathogenicity determinants in Eca, and the impact of functional genomics in expanding our understanding of phytopathogenicity in the Enterobacteriaceae.

Base Sequence↗
PubMed2004

The neural areas that control the retrieval and selection of semantics.

Semantic retrieval consistently activates left inferior frontal regions, yet lesions to these areas do not typically result in semantic deficits. This discrepancy has led to the hypothesis that left prefrontal areas are primarily involved in executive processes while semantic information is retrieved from temporal cortices. We investigated semantic executive processing by changing, over trials, the semantic association to a stimulus. Using fMRI and PET, we demonstrate that changes in semantic association increased activation in temporal as well as frontal areas. The similar effects in temporal and frontal areas suggest that semantic executive processes are not confined to the left inferior frontal cortex but might be distributed throughout the semantic system.

Adult↗
PubMed2004

The displaced equine soft palate as a source of abnormal respiratory noise during expiration.

REASONS FOR PERFORMING STUDY: To develop the technique of respiratory sound analysis for the diagnosis of dorsal displacement of the equine soft palate. OBJECTIVES: To show that 1) the displaced soft palate can spontaneously vibrate in the presence of expiratory airflow; 2) the observed frequency of vibration can be detected in respiratory sound recordings; and 3) the frequency of vibrations measured in cadaveric specimens are similar to those obtained from audio spectra in exercising horses with DDSP. METHODS: Palatal movements and respiratory sounds were recorded from artificially ventilated cadaveric heads. The fundamental mode of palate vibrations calculated from high-speed videoendoscopic recordings was compared with frequencies detected in the audio spectra and with data collected from exercising horses with DDSP. RESULTS: Palate vibrations occurred when air was blown through the trachea. The fundamental mode of vibrations was present in the audio spectra and was not significantly different from those recorded in vivo. CONCLUSIONS: Vibrations of the soft palate are the probable source of expiratory sounds recorded in horses with DDSP. POTENTIAL RELEVANCE: This study strengthens the case for the application of respiratory sound analysis in the diagnosis of DDSP in exercising horses.

Animals↗
PubMed2003

Risk identification, assessment and management in public health practice: a practical approach in one public health department.

BACKGROUND: The continuing identification, assessment and management of risks are key themes for clinical governance. These themes are being integrated into both primary and secondary care practice; however, integration into public health practice appears much slower. This paper describes the recent approach that we have taken in Sheffield, and proposes a model for public health departments to identify, assess and manage risks, which complements other risk management processes and is transferable to other settings. It assumes that public health practice is not a risk-free activity and holds that the process of identifying, assessing and managing risks is a key component to raising standards. METHODS: A number of risk 'management' models were reviewed and a primary care approach was applied to public health practice. A list of potential risks was identified using a number of methods including reflective practice, information from complaints and/or critical incidents. Risks were assessed by likelihood and impact, and were captured in a risk framework. RESULTS: By March 2002, 21 risks had been identified and characterized, and progress had been made to manage 11 of these risks. CONCLUSION: This process, and the development of a risk framework, was useful in identifying a prioritized work programme to improve standards of public health practice in this department. This model can also be used not only for planning risk management activities, continual identification and assessment of risks but also to provide inspiration for other clinical governance activities including public health audit.

England↗
PubMed2002

Sequence of Plasmodium falciparum chromosomes 1, 3-9 and 13.

Since the sequencing of the first two chromosomes of the malaria parasite, Plasmodium falciparum, there has been a concerted effort to sequence and assemble the entire genome of this organism. Here we report the sequence of chromosomes 1, 3-9 and 13 of P. falciparum clone 3D7--these chromosomes account for approximately 55% of the total genome. We describe the methods used to map, sequence and annotate these chromosomes. By comparing our assemblies with the optical map, we indicate the completeness of the resulting sequence. During annotation, we assign Gene Ontology terms to the predicted gene products, and observe clustering of some malaria-specific terms to specific chromosomes. We identify a highly conserved sequence element found in the intergenic region of internal var genes that is not associated with their telomeric counterparts.

Animals↗
PubMed2002

Surface modification of an experimental silicone rubber aimed at reducing initial candidal adhesion.

Silicone rubber, which is a widely used biomaterial, is often used to make soft liners for permanent denture. Colonization of denture soft lining materials by Candida albicans can result in clinical problems. The aim of this study was to chemically modify the surface of an experimental silicone rubber in order to produce a silicone that was less susceptible to candidal colonization. Surface modification was carried out with the use of argon-plasma bombardment followed by silane treatment, which caused the incorporation of either hydrophilic or hydrophobic functional groups onto the surface. Changes in water contact angles and chemical analysis of the materials with scanning ion mass spectroscopy confirmed surface changes. In vitro assays were carried out using C. albicans to measure levels of adherence to the surface-modified silicone after 1 h. C. albicans exhibited very low adherence to all silane-treated surfaces, whether hydrophobic or hydrophilic. This led to the conclusion that incorporated long-chain functional groups were inhibiting the adherence of the yeast, possibly by the formation of a barrier between the surface of the material and the yeast. In conclusion, silane surface treatment of an experimental silicone rubber has been successful in reducing candidal adherence.

Biocompatible Materials↗
PubMed2002

Phase I study of weekly oxaliplatin plus irinotecan in previously treated patients with metastatic colorectal cancer.

BACKGROUND: In vitro synergy between Oxal (oxaliplatin) and CPT-11 (irinotecan) has been reported. Oxaliplatin exerts its antineoplastic activity through the formation of platinum-DNA adducts. Resistance to oxaliplatin is through repair of these adducts, which is inhibited by irinotecan. PATIENTS AND METHODS: Oxaliplatin and irinotecan were administered weekly for 4 weeks followed by a 2-week rest period. The dose of oxaliplatin was escalated first, starting at 30 mg/m(2). Once a dose of 60 mg/m(2) was attained, the weekly dose of irinotecan was escalated, from 40 mg/m(2) to 85 mg/m(2). A total of 49 previously treated patients with metastatic colorectal cancer were entered in order to establish the maximum tolerated dose. Pharmacokinetics of oxaliplatin and irinotecan were analyzed. RESULTS: Forty-nine patients were evaluable for toxicity. The recommended phase II doses for this combination are oxaliplatin 60 mg/m(2) and irinotecan 50 mg/m(2), weekly x 4 q 6 weeks. Diarrhea was the most common dose-limiting toxicity. No pharmacological interactions were noted between oxaliplatin and irinotecan. Twelve of the 47 evaluable patients (26%) achieved a partial response. CONCLUSION: Weekly combination of oxaliplatin and irinotecan appears to be a well tolerated and active regimen in patients previously treated for metastatic colorectal cancer. Further investigations of this regimen are warranted.

Adult↗
PubMed2001

Macrochelation, cyclometallation and G-quartet formation: N3- and C8-bound PdII complexes of adenine and guanine.

The reactions of Pd(II) ions with a series of chelate-tethered derivatives of adenine and guanine have been studied and reveal a difference in the reactivity of the purine bases. Reactions of [PdCl2(MeCN)2] and A-alkyl-enH x Cl (alkyl = propyl or ethyl, A adenine, en = ethylenediamine) yield the monocationic species [PdCl(A-N3-Et-en)]+ (1) and [PdCl(A-N3-Pr-en)]+ (2). Both involve co-ordination at the minor groove site N3 of the nucleobase as confirmed by single-crystal X-ray analysis. Reactions with the analogous G-alkyl-enH x Cl derivatives (G=guanine, alkyl = ethyl or propyl) were more complex with a mixture of species being observed. For G-Et-en HCI a product was isolated which was identified as [PdCl(G-C8-Et-en)]+ (3). This compound contains a biomolecular metal-carbon bond involving C8 of the purine base. Crystallography of a product obtained from reaction of G-Pr-enH x Cl and [Pd(MeCN)4][NO3]2 reveals an octacationic tetrameric complex (4), in which each ligand acts to bridge two metal ions through a combination of a tridentate binding mode involving the diamine and N3 and monodentate coordination at N7.

Adenine↗
PubMed2001

Support of clinician image-related workflow by a user-edited, web-based patient list manager.

Clinician efficiency can be enhanced by worklists that compile useful data for rapid access at the time of need. The authors report development of a web-based, user-edited "Patient List Manager" for the Clinical Image Management System (CIMS). The CIMS List Manager interfaces with the CIMS Archive to provide the user with available studies. It has tools that let the user build personal lists from the available studies. Listed studies are moved from the archive to the cache for rapid access at the time of need. Users can build/edit the list through a browser (without viewing pictures) or from within the image viewer. In this way, the List Manager distributes list building into knowledgeable hands. This is particularly valuable at the current time when health system patient registries are not mature enough to reliably support building build anticipatory patient lists.

Humans↗