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J Carpenter

Publications and source records attributed to J Carpenter.

At least 19 recordsLinked to original sources
PubMed2007

Retrospective analysis of 49 cases of brain abscess and review of the literature.

The case records of 49 patients discharged from St George's Hospital, London, between December 2000 and March 2004 with the diagnosis of brain abscess were reviewed in order to document the epidemiology, causes, treatment, and prognostic factors associated with brain abscess. Brain abscess occurred at all ages, more frequently in men than in women. Headache and altered mental status were common presenting symptoms. The frontal lobe was the most common site. Streptococcal infection was seen most commonly, but staphylococcal infection predominated in cases following neurosurgery. Computed tomography provided sufficient diagnostic information in most cases. All but five patients had early surgical drainage. Cefotaxime and metronidazole were used most often for empirical therapy. Thirty-nine patients recovered fully or had minimal incapacity. Five patients died. Patients with underlying cranial neoplasms or medical conditions had a worse outcome than those with a contiguous focus of infection or post-traumatic abscess. Changes in disease pattern were determined by comparison to a literature review. A PubMed search of the literature using the keywords "brain abscess" was undertaken, and identified papers and relevant citations were reviewed. Compared to earlier series, there was a marked decrease in the number of cases of brain abscess secondary to otitis media and congenital heart disease. There was an increase in the number of cases of brain abscess secondary to neurosurgery and trauma. Changes in the epidemiology of predisposing conditions for brain abscess are associated with changes in the patient population and causative organisms. Though still a potentially fatal infection, there have been recent improvements in diagnosis, treatment, and outcome.

Adolescent↗
PubMed2005

Legionella pneumophila associated with the protozoan Hartmannella vermiformis in a model multi-species biofilm has reduced susceptibility to disinfectants.

Legionella pneumophila will infect biofilm-associated protozoa, and in this way might be protected from disinfectants in potable water systems. A base biofilm containing Pseudomonas aeruginosa, Klebsiella pneumoniae, and Flavobacterium spp. was grown on steel coupons in potable water prior to the addition of L. pneumophila and the protozoan H. vermiformis. After 7 d, coupons were removed and treated with 0.5 mgl(-1) free residual chlorine (FRC) or 0.5 mgl(-1) monochloramine (MCA) for 15, 60, or 180 min or 24 h. In a second experiment, only L. pneumophila and the base biofilm organisms were present but with an identical treatment protocol. Treatment of L. pneumophila for 180 min in a system without H. vermiformis resulted in log reductions of 2.07 and 2.11 for FRC and MCA, respectively. When H. vermiformis was present, however, the treatment resulted in log reductions of 0.67 and 0.81 for FRC and MCA, respectively. A similar pattern was observed for 15 and 60 min contact times. These results indicate that L. pneumophila was less susceptible to MCA or FRC when associated with biofilm-associated H. vermiformis in a model potable water biofilm.

Animals↗
PubMed2004

Ethical issues in social research: difficulties encountered gaining access to children in hospital for research.

BACKGROUND: This paper recounts the difficulties experienced when the authors sought access to children in hospital for social research interviews. These were part of a 2-year study, funded by the Joseph Rowntree Foundation, aiming to explore the numbers, circumstances and experiences of children who spend prolonged periods in health care settings. METHODS: As the intention was to carry out 'guided conversations' with 24 young people in various different NHS locations, permission to do so was sought from a multi-site research ethics committee (MREC), and from several local research ethics committees (LRECs). Agreement was then necessary from NHS trusts, which were asked to nominate a liaison person to help identify and recruit children to the study. Consent was also required from individual parents and children. A series of unexpected delays encountered during this process are discussed in some detail. Eventually a sample of 15 children was achieved. DISCUSSION: The second part of the paper locates this experience within a wider context, noting that similar difficulties gaining access to children in NHS settings have recently been reported by other social researchers. Several possible reasons for this trend are identified and discussed. These relate to the role of MRECs and LRECs in screening social research proposals, recently implemented legislation about data protection, heightened concerns within the NHS about confidentiality and consent, and increasing awareness of the risk of child abuse in health care settings. CONCLUSION: Finally, some suggestions for facilitating the access process are discussed. They include the sensitive and appropriate application of research governance frameworks to social research - including studies within health care settings. Ethical considerations and adequate protection of children are vital but, the authors argue, wherever possible children themselves should be encouraged to decide whether or not to participate in research. In addition, unnecessarily complex access procedures may adversely affect research outcomes.

Attitude↗
PubMed2003

Perceptions of physician order entry: results of a cross-site qualitative study.

OBJECTIVE: To identify perspectives of success factors for implementing computerized physician order entry (POE) in the inpatient setting. DESIGN: Qualitative study by a multidisciplinary team using data from observation, focus groups, and both formal and informal interviews. Data were analyzed using a grounded approach to develop a taxonomy of patterns and themes from the transcripts and field notes. RESULTS: A taxonomy of ten high level themes was developed, including 1) separating POE from other processes, 2) terms, concepts, and connotations, 3) context, 4) tradeoffs, 5) conflicts and contradictions, 6) collaboration and trust, 7) leaders and bridgers, 8) the organization of information, 9) the ongoing nature of implementation, and 10) temporal concerns. CONCLUSION: The identified success factors indicate that POE implementation is an iterative and difficult process, but informants perceive it is worth the effort.

Attitude to Computers↗
PubMed2001

Development of an internally quenched fluorescent substrate and a continuous fluorimetric assay for Streptococcus pneumoniae signal peptidase I.

Signal peptidase (SPase) I is responsible for the cleavage of signal peptides of many secreted proteins in bacteria and serves as a potential target for the development of novel antibacterial agents due to its unique physiological and biochemical properties. In this paper, we describe a novel fluorogenic substrate, KLTFGTVK(Abz)PVQAIAGY(NO2)EWL, in which 2-aminobenzoic acid (Abz) and 3-nitrotyrosine (Y(NO2)) were used as the fluorescent donor and acceptor, respectively. The substrate can be cleaved by both Streptococcus pneumoniae and Escherichia coli SPase I. Upon cleavage of the fluorogenic substrate by SPase I, the fluorescent intensity increases and can be monitored continuously by spectrofluorometer. Kinetic analysis with S. pneumoniae SPase I demonstrated that the K(m) value for the substrate is 118.1 microM, and the k(cat) value is 0.032 s(-1). Mass spectrometric analysis and peptide sequencing of the two cleaved products confirmed that the cleavage occurs specifically at the predicted site. More interestingly, the positively charged lysine in the N-terminus of the substrate was demonstrated to be important for effective cleavage. Phospholipids were found to stimulate the cleavage reaction. This stimulation by phospholipids is dependent upon the N-terminal charge of the substrate, indicating that the interaction of the positively charged substrate with anionic phospholipids is important for maintaining the substrate in certain conformation for cleavage. The substrate and assay described here can be readily automated and utilized for the identification of potential antibacterial agents.

Amino Acid Sequence↗
PubMed2001

Carers and community mental health services.

BACKGROUND: There is a growing appreciation of the role and needs of carers for people with mental health problems. Carers are a diverse group, including partners, relatives and friends who are seen as such by service users. METHODS: Sixty-four carers of people with severe mental health problems served by four different mental health care providers were interviewed using the Experiences of Care-giving Inventory. The districts were selected to differentiate services that are targeted at more severely impaired users from those that include a wider spectrum, and to contrast services that have greater integration between health and social care providers with those whose health and social care agencies operate relatively discretely. RESULTS: In the two districts where service users had more severe mental health problems, carers worried more about negative symptoms and thought less about good aspects of the caring relationship. In the two districts where health and social services worked more closely together, carers worried significantly less about the need to back up services. CONCLUSIONS: These findings suggest that service organisation can affect carers, in particular that integration between health and social care for people with mental health problems may benefit carers in ways that were hitherto unproven. They highlight the needs of carers for younger people. They show that the ECI is a useful instrument in measuring the impact of caring for people with severe mental health problems.

Adult↗
PubMed2001

Endovascular repair of aortic aneurysms: critical events and adjunctive procedures.

OBJECTIVE: We sought to define the learning curve relative to the incidence and range of intraoperative problems and to establish guidelines for troubleshooting during the endovascular repair of infrarenal aortic aneurysms. METHODS: We prospectively evaluated our first 75 consecutive cases over a 12-month period and focused on perioperative critical events and adjunctive procedures as categorical outcome measures collected during the operation. Patients were separated into three groups on the basis of the date of their operation, such that group 1 consisted of our first 25 cases, group 2 our next 25 cases, and group 3 our last 25 cases. RESULTS: At least one critical event and adjunctive procedure marked 67 (89%) of 75 cases. In 51%, there were at least two critical events and adjunctive procedures. There were no immediate open conversions or intraoperative deaths. Access problems occurred in 28% of the 75 cases and were addressed by use of brachial-femoral artery access (30%), iliac artery/aortic bifurcation balloon angioplasty (8%), and iliofemoral conduits (4%). Graft foreshortening was the most common deployment event (44%), necessitating distal covered extensions. Iliac graft limb twists and kinks occurred in 12% of cases and were managed with balloon angioplasty and uncovered stents. General incidents included balloon ruptures (10%), arterial dissections (6%), iliac artery rupture (2.6%), and lower extremity ischemia (4%). The two cases of iliac artery rupture were managed with distal covered extensions, and there were no cases of atheroemboli. Intraoperative endoleaks were encountered in 44% of the cases and included proximal attachment sites (15%), distal attachment sites (9%), type 2 sources, and "blushes." Management of intraoperative endoleaks included proximal/distal covered extensions and re-ballooning. Our 30-day endoleak rate was 20%. The incidence of critical events did not decrease in the latter one third compared with the first two thirds of cases. CONCLUSIONS: Critical events occur frequently during endovascular repair of aortic aneurysms. The intraoperative problems range from the common endoleaks, access and deployment issues, and balloon ruptures, to rare but life-threatening complications such as iliac artery rupture. A toolbox of accessories that includes wires, catheters, large balloons, covered proximal and distal extensions, and uncovered stents is essential given the frequency of adjunctive procedures. Successful aortic endografting requires more than mere familiarity with basic endovascular techniques.

Aortic Aneurysm↗
PubMed2001

A diffusion of innovations model of physician order entry.

OBJECTIVE: To interpret the results of a cross-site study of physician order entry (POE) in hospitals using a diffusion of innovations theory framework. METHODS: Qualitative study using observation, focus groups, and interviews. Data were analyzed by an interdisciplinary team of researchers using a grounded approach to identify themes. Themes were then interpreted using classical Diffusion of Innovations (DOI) theory as described by Rogers [1]. RESULTS: Four high level themes were identified: organizational issues; clinical and professional issues; technology implementation issues; and issues related to the organization of information and knowledge. Further analysis using the DOI framework indicated that POE is an especially complex information technology innovation when one considers communication, time, and social system issues in addition to attributes of the innovation itself. CONCLUSION: Implementation strategies for POE should be designed to account for its complex nature. The ideal would be a system that is both customizable and integrated with other parts of the information system, is implemented with maximum involvement of users and high levels of support, and is surrounded by an atmosphere of trust and collaboration.

Diffusion of Innovation↗
PubMed2000

Bootstrap confidence intervals: when, which, what? A practical guide for medical statisticians.

Since the early 1980s, a bewildering array of methods for constructing bootstrap confidence intervals have been proposed. In this article, we address the following questions. First, when should bootstrap confidence intervals be used. Secondly, which method should be chosen, and thirdly, how should it be implemented. In order to do this, we review the common algorithms for resampling and methods for constructing bootstrap confidence intervals, together with some less well known ones, highlighting their strengths and weaknesses. We then present a simulation study, a flow chart for choosing an appropriate method and a survival analysis example.

Algorithms↗
PubMed2000

Brachial artery catheterization to facilitate endovascular grafting of abdominal aortic aneurysm: safety and rationale.

PURPOSE: Endovascular treatment of abdominal aortic aneurysms (AAAs) is a technically demanding procedure that is based on the complexity and multiplicity of steps and the guidewire and catheter manipulations required. Brachial artery catheterization is an adjunctive technique that can facilitate the placement of an endoluminal prosthesis. METHODS: Brachial access was used during endoluminal AAA repair in 79 of 103 consecutive patients with a modular-design stent-graft prosthesis at two institutions. RESULTS: Left brachial access facilitated (1) angiography to guide juxtarenal device deployment, (2) antegrade contralateral limb access, (3) device delivery through disadvantaged iliac arteries by means of a brachial femoral wire, (4) access to renal arteries when necessary, and (5) catheter exchanges and a reduction in fluoroscopic positional changes. Complications included one puncture-site pseudoaneurysm, seven hematomas, and 29 patients with extensive ecchymosis. The length of stay was not prolonged in any case. There were no embolic, oculocerebral, or ischemic upper extremity events. CONCLUSIONS: Brachial artery catheterization, as an adjunctive technique to endoluminal AAA repair, offers noteworthy technical advantages with few, but self-limiting complications.

Angiography↗
PubMed2000

Field-emission scanning electron microscopy of resin-dentin interface morphology of seven dentin adhesive systems.

PURPOSE: The purpose of this study was to evaluate the resin-dentin interface morphology of 7 resin-based dentin adhesive systems (Solid Bond, EBS-Multi, PermaQuik, One Coat Bond, Gluma One Bond, Prime & Bond NT/NRC, and Clearfil Liner Bond 2V). MATERIALS AND METHODS: Fourteen dentin disks 1.0 mm thick were obtained from superficial occlusal dentin of extracted human third molars, and finished with wet 600-grit silicon carbide paper. Two dentin disks were bonded using each of the adhesives above according to the manufacturers' instructions, and a thin layer of flowable resin composite was applied. The specimens were kept in tap water for 24 h at 37 degrees C, and then assigned to one of two observational techniques: a fracture technique and an acid-base technique. Fracture technique: shallow grooves were cut, fixed in 10% buffered formalin, and dehydrated in an ascending ethanol series up to 100%, critical-point dried, and fractured along the prepared grooves. Acid-base technique: the specimens were embedded in epoxy resin, sectioned through the center, polished with diamond paste down to 0.25-micron particle size, and treated with 10% orthophosphoric acid for 10 s and 5% sodium hypochlorite for 5 min. All the specimens were mounted on aluminum stubs, gold sputter coated, and observed using field-emission scanning electron microscopy (FE-SEM). RESULTS: All the dentin adhesive systems showed hybrid layer formation, but the thickness varied depending on the bonding system used. The self-etching priming systems (Prime & Bond NT/NRC and Clearfil Liner Bond 2V) showed the thinnest hybrid layer at 1 to 2 microns, whereas the "single-bottle" system (Gluma One Bond) exhibited the thickest hybrid layer at 8 to 16 microns. CONCLUSION: The ultramorphological structures of dentin bonding systems are determined by the composition of each system. Characterization of the interface of the adhesive system using the fracture technique provides additional information regarding the pattern of resin infiltration in some dentin bonding systems.

Adhesives↗
PubMed1999

The calibration and validation of a phase-modulated near-infrared cerebral oximeter.

OBJECTIVE: This study was undertaken to compare the cerebral oxygenation measured by an experimental phase-modulated near-infrared (NIR) spectroscopy system with capillary saturation estimated from jugular venous oxygen saturation. METHODS: Jugular venous catheters were placed in 30 patients undergoing carotid endarterectomy and 194 measurements of venous oxygen saturation were obtained intra operatively. Simultaneous measurement of optical path length at 754, 785, and 816 nm was performed using a phase-modulated near-infrared spectroscopy system. Optical calibration was performed using both an optical bench and a scattering mold. Hemoglobin saturation was calculated from NIR measurements using equations derived from diffusion theory. Capillary saturation was calculated from the arterial and venous saturations. RESULTS: Jugular venous saturations ranged from 41 to 92%. When calibrated using the optical bench, the NIR estimates of hemoglobin saturation deviated from estimated capillary values by an average of 2.6% bias and 4.3% deviation. No systematic bias was noted. NIR values derived from mold calibration were less accurate and precise (4.6% bias and 6.9% deviation.) Use of the initial venous sample as an in vivo calibration improved the accuracy of the mold calibration but did not alter the performance of the bench calibration. CONCLUSIONS: Under the conditions tested, an experimental phase-modulated near-infrared spectroscopy system calibrated using an optical bench agreed with capillary saturation estimated from jugular venous samples. Further work is necessary to demonstrate valid performance of the system under other conditions.

Aged↗
PubMed1999

A massive epidemic of multidrug-resistant typhoid fever in Tajikistan associated with consumption of municipal water.

From 1 January through 30 June 1997, 8901 cases of typhoid fever and 95 associated deaths were reported in Dushanbe, Tajikistan. Of 29 Salmonella serotype Typhi isolates tested, 27 (93%) were resistant to ampicillin, chloramphenicol, nalidixic acid, streptomycin, sulfisoxazole, tetracycline, and trimethoprim-sulfamethoxazole. In a case-control study of 45 patients and 123 controls, Salmonella Typhi infection was associated with drinking unboiled water (matched odds ratio, 7; 95% confidence interval, 3-24; P<.001). Of tap water samples, 97% showed fecal coliform contamination (mean level, 175 cfu/100 mL). Samples taken from water treatment plants revealed that fecal coliform contamination occurred both before and after treatment. Lack of chlorination, equipment failure, and back-siphonage in the water distribution system led to contamination of drinking water. After chlorination and coagulation were begun at the treatment plants and a water conservation campaign was initiated to improve water pressure, the incidence of typhoid fever declined dramatically.

Case-Control Studies↗
PubMed1999

Stable antisense RNA expression neutralizes the activity of low-density lipoprotein receptor-related protein and promotes urokinase accumulation in the medium of an astrocytic tumor cell line.

Low-density lipoprotein receptor-related protein (LRP) binds and internalizes multiple ligands that are structurally and functionally diverse. However, the effects of LRP on cellular phenotype remain unclear. To study LRP in human astrocytic tumor cells, we designed LRP antisense RNA expression constructs in which the antisense cDNA fragment was expressed under the control of the cytomegalovirus (CMV) promoter. U-1242 MG astrocytic tumor cells were transfected with the antisense constructs and cloned from single cells to yield multiple cell lines with decreased LRP expression. Further studies were performed with two cell lines in which LRP antigen was completely eliminated (L(alpha)42) or substantially decreased (Lalpha47), as determined by Western blot analysis. Untransfected U-1242 MG cells and cells that were stably transfected with empty vector (pBK-CMV) bound activated alpha2-macroglobulin (alpha2M) in a specific and saturable manner. The Bmax was about 5000 receptors/cell. Lalpha42 cells did not bind alpha2M, and binding was decreased by >60% in Lalpha47 cells. Lalpha42 and Lalpha47 cells also demonstrated reduced susceptibility to the cytotoxin, Pseudomonas exotoxin A, and accumulated greatly increased levels of urokinase-type plasminogen activator (uPA) in conditioned medium. The accumulation of uPA demonstrates a major role for LRP in the catabolism of this protein in astrocytic tumor cells. The LRP-deficient cell lines, developed using antisense technology, represent a new model system for studying LRP function in astrocytes.

ADP Ribose Transferases↗
PubMed1999

Operation and organisation of services for people with severe mental illness in the UK. A survey of the Care Programme Approach.

BACKGROUND: Since 1991, English mental health policy guidelines have been explicit in recommending inter-professional working, involvement of patients and carers, harmonisation between health and social services and targeting at people with severe mental illness. AIMS: To explore the structure and operation of mental health services in practice and relate them to measurable data. METHOD: A survey of mental health trusts was conducted in 1997-1998. Responses were compared with a concurrent survey of social services departments. Some qualitative data were collected. Harmonisation and targeting scores were devised and tested for association. RESULTS: The response rate was 79%. The frequency with which different professionals, patients and carers were involved in the care process is described. Reasons for this are discussed briefly. Levels of harmonisation and targeting were found to vary widely and to be positively associated. CONCLUSIONS: This survey portrays mental health services' practice in relation to Government policy. However, adherence to guidelines cannot be taken as a guarantee of service quality or efficiency.

Health Care Surveys↗