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Biomedical subjects

S Jan

Publications and source records attributed to S Jan.

At least 19 recordsLinked to original sources
PubMed2006

Access to bone mineral density testing in patients at risk for osteoporosis.

INTRODUCTION: Prior studies have documented suboptimal diagnosis and treatment for osteoporosis in many settings. Consistent predictors of suboptimal management include patient age, physician training, and physician gender. We assessed whether access to bone mineral density (BMD) testing was a predictor of osteoporosis management in an at-risk population of patients from New Jersey. METHODS: Based on health care claims data, we identified three groups of at-risk beneficiaries, including women >or=65 (n=8,283), men and women >or=45 with a fracture (n=740), and men and women >or=45 taking chronic oral glucocorticoids (n=616). As the outcome of interest, we determined whether beneficiaries had undergone a BMD test and/or filled a prescription for a medicine used for osteoporosis (alendronate, calcitonin, hormone therapy, etidronate, risedronate, raloxifene, teriparatide) during the period 1 September 2002-31 August 2004. We assessed the relationship between this outcome and access to BMD testing. Access was characterized using two different measures: (1) the estimated driving time between each beneficiary's residence and the nearest BMD testing center ("driving time") and (2) the number of persons >or=65 years of age per BMD testing machine ("BMD scanner ratio") for each of the 21 counties in New Jersey. RESULTS: Of the 9,640 beneficiaries, we found that 3,104 (32%) had undergone a BMD test, 2,893 (30%) had filled a prescription for an osteoporosis medication, and 4,364 (45%) had one or both. Across the 21 counties of New Jersey, the percentage of at-risk patients who had a BMD test and/or medication for osteoporosis ranged from 38 to 52%. In models adjusted for patient factors and the clustering of patients in counties, driving time was not associated with patients being screened or treated for osteoporosis. The BMD scanner ratio was a weak predictor of osteoporosis management. CONCLUSION: Among beneficiaries of one large health insurer in New Jersey, two different measures of access to BMD testing were not important predictors of receiving testing and/or medications for osteoporosis.

Age Distribution↗
PubMed2006

Fatal fat embolism after vertebroplasty: identification of the high-risk patient.

We report a rare complication of autopsy-proven fat and bone marrow embolization following percutaneous vertebroplasty in a patient who had no evidence of cement leakage. Cement injection was done during one patient encounter, covering 3 vertebral levels by using a unipedicular approach. Patients may have complications even without polymethylmethacrylate leakage.

Aged↗
PubMed2006

Symptomatic refractures after vertebroplasty in patients with steroid-induced osteoporosis.

BACKGROUND AND PURPOSE: Refracture after percutaneous vertebroplasty in patients receiving oral glucocorticoid therapy has caused some patients and referring physicians to have negative perceptions concerning the efficacy of the initial vertebroplasty treatment. The purpose of this study was to analyze symptomatic refractures after vertebroplasty in patients on oral steroid therapy. We hypothesized that the higher refracture rate of patients on oral glucocorticoid therapy after percutaneous vertebroplasty is due not to an inadequacy of the procedure but rather to a naturally higher predisposition of these patients to refracture compared with patients with primary osteoporosis. METHODS: A retrospective analysis was performed on all osteoporosis patients having initial vertebroplasty from August 1999 to August 2003. The follow-up period was limited to 1 year after initial vertebroplasty session, with the last follow-up date ending in August 2004. Data were collected on 387 osteoporosis patients. RESULTS: Of the patients with primary osteoporosis, 20.6% patients refractured whereas 37.8% of the patients with steroid-induced osteoporosis had symptomatic refractures within 1 year of initial vertebroplasty. Relative risk of refracture within 1 year for the patients with steroid-induced osteoporosis was 1.84 compared with the patients with primary osteoporosis. In addition, the patients with steroid-induced osteoporosis were more likely to refracture after their second treatment session (within 1 year of initial vertebroplasty) than those with primary osteoporosis. CONCLUSION: Patients presenting on oral steroid therapy at their initial vertebroplasty are almost twice more likely to have symptomatic refractures than primary osteoporosis patients within 1 year of initial vertebroplasty.

Administration, Oral↗
PubMed2004

GATE: a simulation toolkit for PET and SPECT.

Monte Carlo simulation is an essential tool in emission tomography that can assist in the design of new medical imaging devices, the optimization of acquisition protocols and the development or assessment of image reconstruction algorithms and correction techniques. GATE, the Geant4 Application for Tomographic Emission, encapsulates the Geant4 libraries to achieve a modular, versatile, scripted simulation toolkit adapted to the field of nuclear medicine. In particular, GATE allows the description of time-dependent phenomena such as source or detector movement, and source decay kinetics. This feature makes it possible to simulate time curves under realistic acquisition conditions and to test dynamic reconstruction algorithms. This paper gives a detailed description of the design and development of GATE by the OpenGATE collaboration, whose continuing objective is to improve, document and validate GATE by simulating commercially available imaging systems for PET and SPECT. Large effort is also invested in the ability and the flexibility to model novel detection systems or systems still under design. A public release of GATE licensed under the GNU Lesser General Public License can be downloaded at http:/www-lphe.epfl.ch/GATE/. Two benchmarks developed for PET and SPECT to test the installation of GATE and to serve as a tutorial for the users are presented. Extensive validation of the GATE simulation platform has been started, comparing simulations and measurements on commercially available acquisition systems. References to those results are listed. The future prospects towards the gridification of GATE and its extension to other domains such as dosimetry are also discussed.

Computer Simulation↗
PubMed2004

The surprising diversity of Delta6-desaturase substrates.

A single gene encoding a Delta6-desaturase (FADS2) has been isolated and characterized in mammalian species. This Delta6-desaturase plays a major role in the biosynthesis of PUFAs (polyunsaturated fatty acids). It catalyses the rate-limiting desaturation of linoleic acid (C(18:2) n-6) and alpha-linolenic acid (C(18:3) n-3) required for the biosynthesis of long-chain PUFAs. Moreover, recent studies have provided strong evidence that this Delta6-desaturase also acts on 24-carbon PUFAs of both the n-6 and n-3 series. Another substrate of this Delta6-desaturase has been identified through complementary works from different investigators. This Delta6-desaturase acts on a saturated fatty acid, palmitic acid (C(16:0)), leading to the newly characterized biosynthesis of hexadecenoic acid (C(16:1) n-10) or sapienate.

Animals↗
PubMed2000

Institutional considerations in priority setting: transactions cost perspective on PBMA.

Programme budgeting and marginal analysis (PBMA) is increasingly being used as a method of priority setting in the health care sector. Despite this, PBMA has, on occasions, been subject to problems in its application which can be seen as being 'institutional' in nature. This paper examines the extent to which the institutional setting of PBMA affects the way in which it can be conducted. In particular, a transactions costs perspective is taken to analyse the extent to which variation in such costs can alter the incentives of the individual participants. A number of recommendations for improving the sustainability of such projects is then provided. Following this, the implications which this 'institutional' approach has for the evaluation of PBMA are set out.

Budgets↗
PubMed2000

Analysis of helical axes, pivot and envelope in active wrist circumduction.

OBJECTIVE: To study active wrist circumduction and planar moves, in terms of anatomical angles and envelope and of finite helical axes and mean pivot point. DESIGN: We measured the position of the "mean pivot point" and its mean distance to the axes as anatomical angles in an in vivo full range movement. BACKGROUND: The mean pivot point has been used in in vitro and roentgen stereophotogrammetric studies of wrist kinematics. However, the distribution of "3D centers of rotation" has never been presented in a non-invasive in vivo study. METHODS: A light 6 degrees of freedom electrogoniometer was built and employed in vivo to measure circumduction, flexion-extension and radioulnar deviation on both wrists of twenty one volunteers. RESULTS: Results were in general agreement with previously published ranges of wrist planar motion. The circumduction envelope proved to be a relevant representation of active wrist motion. The "mean pivot point" displayed a relative dispersion in localization of this point. CONCLUSION: The pivot results suggest that the wrist acts as a universal joint but with a non fixed location in the capitate head. The major axis of wrist envelope was not skew. RELEVANCE: The envelope and the precise knowledge of the helical axis pivot and its mean distance to the axes could give precious information on wrist functionality and stability after surgical or conservative treatment.

Adult↗
PubMed2000

Resource allocation within Australian indigenous communities: a program for implementing vertical equity.

Given the significant disparities in health and health related disadvantage between Aboriginal and non-Aboriginal Australians, the application of some notion of equity has a role to play in the formulation of policy with respect to Aboriginal health. Aboriginal and Torres Strait Islander has been abbreviated to Aboriginal. There has been considerable debate in Australia as to what the principles of equity should be. This paper discusses the relevance of the principle of vertical equity (the unequal, but equitable, treatment of unequals) to Aboriginal health funding. In particular, the paper advocates pursuing procedural justice as the basis for vertical equity where the focus is on the fairness of how things are done rather than on the distribution of outcomes per se (i.e. distributive justice). Particular attention is paid to how the principle of vertical equity might be handled at a practical level. Details of the approach used in a number of Australian indigenous communities are discussed. It is concluded that there are strong arguments for pursuing procedural justice under vertical equity particularly when there are cultural differences in the way health is defined and when there is importance attached to indigenous involvement in the health care decision making process.

Adolescent↗
PubMed2000

The use of conjoint analysis to elicit community preferences in public health research: a case study of hospital services in South Australia.

AIMS: To demonstrate the use of conjoint analysis (CA) in public health research through a survey of the South Australian community about aspects of their public hospital services. METHODS: A series of focus groups determined the most important attributes in choice of hospital services. These were built into a CA survey, using the discrete choice approach. The survey was posted to a representative sample of 700 South Australians. Theoretical validity, internal consistency and non-response bias were all investigated. RESULTS: Some 231 individuals returned the questionnaire. The attribute, 'improvement in complication rates' was positively associated with choice of hospital. Three attributes were found to be negatively associated with such choice: 'waiting times for casualty', 'waiting times for elective surgery' and, anomalously, 'parking and transport facilities'. 'Travel time' and the cost attribute, 'Medicare levy' were not statistically significant. Trade-offs between the significant attributes were estimated, as were satisfaction or utility scores for different ways of providing hospital services. Results concerning internal consistency and internal validity were encouraging, but some potential for non-response bias was detected. CONCLUSION: A high premium is placed on the quality of hospital care and members of the community are prepared to choose between hospitals largely on the basis of outcomes and length of waiting times for elective surgery and in casualty. IMPLICATIONS: CA can yield potentially policy-relevant information about community preferences for health services.

Adult↗
PubMed1999

A new perspective on economic analysis in health care? A critical review of 'The Economics of Health Reconsidered' by Tom Rice.

A recently published book, 'The Economics of Health Reconsidered' by Tom Rice, provides a strong critique of the role of markets in health care. Many of the issues of 'market failure' raised by Rice, however, have been, to varying extents, recognised previously in the health economics literature (at least outside the U.S.). What perhaps sets Rice's book apart from previous attempts to document such issues is its elegance and the methodical manner in which this critique is delivered. Significantly the critique is based solely on conventional economic arguments. There has, however, been an emerging strand of the health economics literature not acknowledged in Rice's book which has approached some of these issues of market failure from a different perspective. Notably this research has involved, in part, borrowing from the ideas and methodological traditions of other disciplines. The emphasis in this work has been to expand the scope and the concerns of economic analysis in health care.

Delivery of Health Care↗
PubMed1998

Subtilisin-related serine proteases in the mammalian constitutive secretory pathway.

Proteolytic cleavage is a key step in the activation of many secreted proteins. Since the identification of the prototype yeast enzyme Kex2, seven subtilisin-related serine proteases, together with a number of isoforms, have been identified in mammalian cells, five of which act within the constitutive secretory pathway. Overlapping expression patterns and substrate specificities complicate analysis but individual roles are beginning to emerge for some members of the group.

Animals↗
PubMed1998

A holistic approach to the economic evaluation of health programs using institutionalist methodology.

The paper examines possibilities for employing more holistic approaches to the evaluation of health care programs. It is argued that the reductionism of conventional forms of economic evaluation, where value (or benefit) is seen in terms of either health consequences or individuals' utility, can cause a number of aspects of such programs to be overlooked. As such, this imposes fairly strict limits on the capacity of economic evaluation to inform public policy. In contrast, institutionalist economic theory in common with the community development approach to health promotion is an area of research which acknowledges that change to the broader socio-political environment can be a source of value. It is suggested that this idea has, for instance, significance for the evaluation of indigenous health programs where notions of "cultural appropriateness" have strong influence over the effectiveness and acceptability of such programs. It is concluded that no one evaluative approach is appropriate in all situations and that a greater receptiveness to broader sources of social value can help to improve the way evaluations are conducted.

Evaluation Studies as Topic↗
PubMed1997

Vertical equity: weighting outcomes? or establishing procedures?

Considerations of equity in the health policy literature have in the main focussed on horizontal equity (the equal treatment of equals) and as a consequence have tended to overlook vertical equity (the unequal, but equitable, treatment of unequals). There is evidence from earlier, if preliminary, work carried out by the authors and a colleague that health care decision makers may well want to embrace concerns for vertical equity in the allocation of health service resources. This paper examines some possibilities for incorporating vertical equity into health care policy through distributive and/or procedural justice. While no firm solutions are offered, it is suggested that the idea of fitting John Broome's notion of 'claims' within a communitarian framework holds promise.

Australia↗
PubMed1996

The Swedish UPA score: an administrative tool for identification of underprivileged areas.

The purpose was to construct a Swedish social deprivation index analogous to the underprivileged area (UPA) score, used in the UK to distribute resources to general practice for patients resident in the most underprivileged areas. UPA scores were calculated using 1990 Swedish census data and the 1992 unemployment and migration registers for all 8,502 SAMS (small area market statistics) areas with more than 50 inhabitants. Selection of the eight variables included in the score and weights attached to each were derived from a national survey of general practitioners in the UK representing the degree to which they considered that each factor increased their workload or pressure on services. The UPA score for each area is the sum of the eight normalised (arc sin square root), standardised (z scores) and weighted variables for that area. The distribution of UPA scores ranged from -79.13, in the most affluent areas to 46.10 in the most underprivileged areas. It was found that a wide range of social deprivation exists at small area level.

England↗