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Biomedical subjects

John Baker

Publications and source records attributed to John Baker.

At least 19 recordsLinked to original sources
PubMed2006

Simultaneous measurement of temperature and chemical species concentrations with a holographic interferometer and infrared absorption.

What is believed to be a new technique that allows for the simultaneous measurement of 2D temperature and chemical species concentration profiles with high spatial resolution and fast time response was developed and tested successfully by measuring a thin layer of fuel vapor created over a volatile fuel surface. Normal propanol was placed in an open-top rectangular container, and n-propanol fuel vapor was formed over the propanol surface in a quiescent laboratory environment. An IR beam with a wavelength of 8-13 mum emitted from a heated plate and a He-Ne laser beam with a wavelength of 632 nm were combined and passed through the n-propanol vapor layer, and both beams were absorbed by the vapor layer. The absorption of the IR beam was recorded by an IR camera, and the He-Ne laser was used to form a holographic interferogram. Two-dimensional temperature and propanol vapor concentration profiles were, respectively, determined by the IR absorption and the fringe pattern associated with the holographic interferogram. This new measurement technique is a significant improvement over the dual wavelength holographic interferometry that has been used previously to measure temperature and fuel concentration, and it is ready for application under different types of fire and flame conditions.

Journal Article↗
PubMed2006

Ethnic differences in Type 2 diabetes care and outcomes in Auckland: a multiethnic community in New Zealand.

INTRODUCTION: In New Zealand, Maori and Pacific (mostly of Samoan, Tongan, Niuean, or Cook Islands origin) people with Type 2 diabetes are more likely to suffer poor outcomes than other New Zealanders. Responsibility for addressing this outcome differential is falling on primary care and general practice in particular. This paper compares the general practice care provided to people with Type 2 diabetes in South and West Auckland, according to ethnicity. METHOD: An external audit of general practice diabetes care is carried out in South and West Auckland by the Diabetes Care Support Service. The results of 5917 routine patient audits carried out in 2003 are included in this study. Number of visits, recording of important information, risk factors, and treatments are compared between different ethnic groups. RESULTS: Maori and Pacific people with diabetes who attend a regular GP had a higher average number of consultations than Europeans (5.7, 5.4, and 4.8 visits per year respectively). They were as likely as Europeans to have undergone important regular examinations and investigations. Maori were more likely than Europeans to be on some treatments. However, Maori and Pacific people were more likely to have a range of adverse risk factors for diabetes complications than Europeans. These include being a smoker (35, 18, and 13% respectively), having an HbA1c greater than 8% (50, 56, 23%), and having microalbuminuria (55, 50, 27%). DISCUSSION: Although there were no large differences in the process measures of general practice diabetes care provided to different ethnic groups in South and West Auckland, Maori and Pacific people were not achieving the same outcomes of care in terms of risk factors for diabetes complications. Many of these risk factors are influenced by other factors in the wider community; however the New Zealand health system needs to consider how it can better address these differences.

Aged↗
PubMed2006

How expert are the experts? An exploration of the concept of 'expert' within Delphi panel techniques.

The use of the term 'expert' occurs widely in healthcare research, in the context of national guidelines and consensus methods for the development of clinical protocols. Within consensus methods of research, especially Delphi panel techniques, the use of 'experts' is fundamental to reliability. Yet literature fails to debate the practicalities of defining 'experts' for use within Delphi panel research. This paper, by John Baker and colleagues, draws on methodological literature and discusses the concepts and elements of 'experts'. It concludes with recommendations for researchers to ensure experts for future Delphi research.

Delphi Technique↗
PubMed2005

Prevention of distal embolization and no-reflow in patients with acute myocardial infarction and total occlusion in the infarct-related vessel: a subgroup analysis of the cohort of acute revascularization in myocardial infarction with excimer laser-CARMEL multicenter study.

To overcome the adverse complications of percutaneous coronary interventions in thrombus laden lesions (i.e., distal embolization, platelet activation, no-reflow phenomenon), mechanical removal of the thrombus or distal embolization protection devices are frequently required. Pulsed-wave ultraviolet excimer laser light at 308 nm can vaporize thrombus, suppress platelet aggregation, and, unlike other thrombectomy devices, ablate the underlying plaque. The following multicenter registry was instituted to evaluate the safety and efficacy of laser ablation in patients presenting with acute myocardial infarction (AMI) complicated by persistent thrombotic occlusions. Patients with AMI and complete thrombotic occlusion of the infarct-related vessel were included in eight participating centers. Patients with further compromising conditions (i.e., cardiogenic shock, thrombolysis failures) were also included. Primary endpoint was procedural respective laser success; secondary combined endpoints were TIMI flow and % stenosis by quantitative coronary analysis and visual assessment at 1-month follow-up. Eighty-four percent of all patients enrolled (n = 56) had a very large thrombus burden (TIMI thrombus scale > or = 3), and 49% were compromised by complex clinical presentation, i.e., cardiogenic shock (21%), degenerated saphenous vein grafts (26%), or thrombolysis failures (5%). Laser success was achieved in 89%, angiographic success in 93%, and the overall procedural success rate was 86%. The angiographic prelaser total occlusion was reduced angiographically to 58% +/- 25% after laser treatment and to 4% +/- 13% final residual stenosis after adjunctive balloon angioplasty and/or stent placement. TIMI flow increased significantly from grade 0 to 2.7 +/- 0.5 following laser ablation (P < 0.001) and 3.0 +/- 0.2 upon completion of the angioplasty procedure (P > 0.001 vs. baseline). Distal embolizations occurred in 4%, no-reflow was observed in 2%, and perforations in 0.6% of cases. Laser-associated major dissections occurred in 4% of cases, and total MACE was 13%. The safety and efficacy of excimer laser for thrombus dissolution in a cohort of high-risk patients presenting with AMI and total thrombotic occlusion in the infarct-related vessel are encouraging and should lead to further investigation.

Aged↗
PubMed2005

The grief evaluation measure (GEM): an initial validation study.

This article describes the development of the Grief Evaluation Measure (GEM), a new instrument designed to screen for the development of a complicated mourning response in a bereaved adult. The GEM provides a quantitative and qualitative assessment of risk factors, including the mourner's loss and medical history, coping resources before and after the death, and circumstances surrounding the death. It is designed to provide an in-depth evaluation of the bereaved adult's subjective grief experience and associated symptoms. Reliability and validity studies were conducted with two samples of bereaved adults (n = 23 and n = 92, respectively) from various clinical and support settings. Data on the two central sections of the GEM that assess the mourner's grief response and the level of symptomatology are described. Results indicate that the GEM's internal consistency and test-retest reliability are high. The GEM demonstrates good concurrent validity for established measures of bereavement, trauma, and physical and psychiatric symptoms, and good predictive validity for mourner adjustment one year after initial assessment. Plans for future development and an invitation for other researchers to collaborate with research on the GEM are also discussed.

Adaptation, Psychological↗
PubMed2005

Specialist educational intervention for mental health nursing staff: delivery, content and personal impact.

AIM: This paper reports a study to ascertain the views of acute ward-based mental health nursing staff on the delivery, content and personal impact of an innovative 18-day, whole team educational intervention in acute mental health care. BACKGROUND: There are grave concerns internationally about the quality of inpatient mental health care for people with acute psychiatric problems. Educational courses are needed to improve these services. However, existing schemes are often selective, hard to access and limited to developing highly specialist skills for senior nurses. They have also been criticized for making no difference to clinical practice. There is little evidence to guide the development of these or alternative team-based courses. METHOD: Qualitative data were collected over a 6-week period using 12 focus group interviews and individual questionnaires. RESULTS: Four themes were identified. The joint education of nursing staff from different organizations was welcomed and reduced feelings of ward isolation. Mixing qualified and unqualified staff was not regarded positively. In terms of course content and learning themes, unqualified staff were more likely to report positive learning outcomes for knowledge, skills, attitude, morale and personal development; qualified nurses were more likely to indicate positive outcomes in anonymized data from questionnaires than from focus groups. Both groups reported little chance of knowledge implementation without changes in the organization of care. CONCLUSION: Whilst it may be desirable to educate whole nursing teams, more benefit might be gained from shared education between several organizations and separating the education of qualified and unqualified staff before combining these groups in team education. Participants remained pessimistic about their chances of implementing new knowledge and skills in current acute inpatient mental health environments.

Acute Disease↗
PubMed2005

Specialist educational intervention for acute inpatient mental health nursing staff: service user views and effects on nursing quality.

AIM: This paper reports a study to evaluate the impact of an innovative 18-day educational intervention for acute ward-based mental healthcare nursing staff on documented quality of nursing care and on service user views of that care. BACKGROUND: There are grave concerns internationally about the quality of inpatient mental health care for people with acute psychiatric problems. It is claimed that specialist educational courses are needed to improve these services. However, whilst such courses may lead to positive learning outcomes for participants, the impact on the actual care of service users is unknown. METHOD: An uncontrolled before-and-after evaluation of three acute mental health wards from different United Kingdom National Health Service trusts was carried out. Quality of nursing care was evaluated by extracting documentary evidence from service user records, assessed by two independent researchers according to predefined quality criteria. The views of a purposive sample of mental health service users, currently receiving services from the three designated wards, were ascertained by semi-structured interview. RESULTS: Both documentary evidence and service user views revealed some important baseline deficiencies in the quality of care offered at the study sites. Following the educational intervention, statistically significant improvements were observed in the quality of care planning, initial assessments and the provision of therapeutic care. No statistically significant changes were observed in the quality of risk assessments, medication management or external agency involvement. CONCLUSIONS: Education can have an impact on nursing care but may not be sufficient alone to change mental healthcare practices on acute inpatient wards in the radical manner demanded by policymakers and service user lobby groups. Educational interventions need to be implemented in conjunction with organizational changes that are specifically designed to maximize the opportunities presented by a newly skilled and positive workforce.

Acute Disease↗
PubMed2004

Periprosthetic supracondylar femur fractures following total knee arthroplasty.

Periprosthetic supracondylar femur fractures following total knee arthroplasty (TKA) are an infrequent, but devastating, complication. From 1998 to 2000, we treated 30 supracondylar femur fractures above TKAs. Eighteen fractures were managed with retrograde intramedullary rod fixation (FIMR) and the other 12 fractures with traditional open reduction with internal fixation (ORIF). Follow-up averaged 3 years, with Knee Society knee scores being 84 and 82, respectively. Complications included 1 above-knee amputation for deep sepsis and 1 nonunion with varus alignment. FIMR appears to be the treatment of choice when it is feasible. However, traditional ORIF also may yield satisfactory results in those designs that cannot accommodate retrograde FIMR fixation.

Aged↗
PubMed2004

Cementless bipolar hemiarthroplasty for displaced femoral neck fractures in the elderly.

Controversy exists regarding the use of cementless femoral fixation for hip arthroplasties in elderly patients. This study reviews the clinical and radiographic outcomes of cementless bipolar hemiarthroplasties in patients older than 65 years of age. From 1998 to 2000, 256 cementless bipolar hemiarthroplasties were performed in 248 patients with displaced femoral neck fractures who had a mean age of 77 years. The mean final follow-up was 3.5 years and Harris hip scores averaged 82 points. Two loose femoral stems were revised and the rest of the implants were radiographically stable and demonstrated evidence of bone ingrowth. Six patients had debilitating groin pain necessitating conversion to total hip arthroplasty. Cementless bipolar hemiarthroplasty can be safely performed in elderly patients and can provide predictable clinical and radiographic results.

Aged↗
PubMed2004

Embryonal rhabdomyosarcoma (sarcoma botryoides) of the cervix presenting as a cervical polyp treated with fertility-sparing surgery and adjuvant chemotherapy.

BACKGROUND: Embryonal rhabdomyosarcoma (sarcoma botryoides) of the female genital tract is rare in the cervix. It tends to occur in children and young women, and appears to have a better prognosis than sarcoma botryoides of the vagina and uterus. CASE: We report a case of embryonal rhabdomyosarcoma (sarcoma botryoides) presenting as a cervical polyp in a 19-year-old female. The tumor was composed of rhabdomyoblasts of varying differentiation dispersed within a loose, myxoid stroma, and formed a distinct 'cambium' layer beneath the epithelium. The patient was successfully treated with fertility-sparing surgery and adjuvant chemotherapy. CONCLUSIONS: Awareness of this uncommon lesion in this site and its clinical implications is important to avoid misdiagnosis. Therapy has recently inclined towards conservative treatment.

Adult↗
PubMed2004

Excimer laser revascularization of saphenous vein grafts in acute myocardial infarction.

Patients who develop acute myocardial infarction due to occlusion in a saphenous vein graft (SVG) constitute a revascularization challenge. Excimer laser angioplasty may have a potential advantage in the treatment of SVGs, since its 308 nanometer wavelength is avidly absorbed by both atherosclerotic plaque and thrombus. The data presented herein support the notion that excimer laser angioplasty is a technology that has a potential role in achieving adequate revascularization outcomes in this selected, high-risk patient population.

Aged↗
PubMed2003

Strategies for educational action to meet veterinary medicine's role in biodefense and public health.

It is clear that the profession is not well prepared to respond to society's needs in bio-defense and public health. The imperatives that face the veterinary profession, as emphasized by the agenda for action conference deliberations that are reported in this issue of the journal, require action on many fronts, but possibly none more essential than to address how veterinary education needs to change to meet these challenges. Addressing these needs, participants at the agenda for action conference met in groups of 30 to 50 to shape approaches that would address these key questions. The 161 participants were broadly representative of government, private practice, corporate practice, organized veterinary medicine, and academia (Appendix A). Reported here are the results of those deliberations, with each of the seven sections written up by the discussion leader. Included in the participants were 20 students, representative of eight different veterinary colleges, who both participated in the group discussions and have presented their own report.

Animals↗
PubMed2002

Ubiquitylation of MHC class I by the K3 viral protein signals internalization and TSG101-dependent degradation.

The Kaposi's sarcoma-associated herpes virus gene product K3 (KK3) subverts the MHC class I antigen presentation pathway by downregulating MHC class I from the plasma membrane. We now show that KK3 associates with MHC class I molecules and promotes ubiquitylation of class I after export from the endoplasmic reticulum. Ubiquitylation requires the KK3 N-terminal plant homeodomain and provides the signal for class I internalization at the plasma membrane. Once internalized, ubiquitylated MHC class I is targeted to the late endocytic pathway, where it is degraded. Depletion by small interfering RNA of TSG101, a ubiquitin enzyme 2 variant protein involved in late endosomal sorting, prevents class I degradation and preserves cell surface class I expression in KK3-expressing cells. These results suggest a mechanism by which the KK3-induced class I ubiquitylation provides a signal for both internalization and sorting to the late endosomal pathway for degradation. KK3 is the first viral gene product that subverts the trafficking of a host protein via the ubiquitin-dependent endosomal sorting machinery.

DNA-Binding Proteins↗
PubMed2002

Bilateral panuveitis in a child with hypohidrotic ectodermal dysplasia.

PURPOSE: To report a case of bilateral panuveitis in a patient with hypohidrotic ectodermal dysplasia. DESIGN: Interventional case report. METHODS: A 6-year-old African-American boy with hypohidrotic ectodermal dysplasia presented with pain, photophobia, and decreased vision in both eyes. RESULTS: Findings included severe bilateral panuveitis with optic disk edema, macular epiretinal membrane, peripheral retinal vasculitis, and retinitis. All other known causes of panuveitis were explored and ruled out. CONCLUSIONS: The abnormal development of tissues of ectodermal origin evident in hypohidrotic ectodermal dysplasia may include a predisposition to panuveitis.

Child↗