Analytical technique for quantification of selected resorbable calcium phosphate bone void fillers with the use of polarized-light microscopy

Synthetic calcium phosphate bone void fillers promote varying rates of bone formation and material resorption depending on chemistry, porosity, pore structure, and implant site. The objective of this study was to quantify the resorption of a novel ultraporous beta-tricalcium phosphate cancellous bone void filler with simultaneous quantification of bone formation in a canine humerus model. Potential measurement error involved in conventional histomorphometry using Von Kossa stains inspired the development of a new technique. This technique utilizes bright-field and polarized-light microscopy in conjunction with image analysis software, allowing more accurate histomorphometry. This technique was validated with two separate controlled experiments. Scanning electron microscopy further supported the results. The findings suggest that the use of polarized-light microscopy combined with image analysis software can be an effective tool in simultaneously quantifying calcium phosphate resorption and bone formation.     

Developing health science students into integrated health professionals: a practical tool for learning

Background  

An integrated sense of professionalism enables health professionals to draw on relevant knowledge in context and to apply a set of professional responsibilities and ethical principles in the midst of changing work environments [1, 2]. Inculcating professionalism is therefore a critical goal of health professional education. Two multi-professional courses for first year Health Science students at the University of Cape Town, South Africa aim to lay the foundation for becoming an integrated health professional [3]. In these courses a diagram depicting the domains of the integrated health professional is used to focus the content of small group experiential exercises towards an appreciation of professionalism. The diagram serves as an organising framework for conceptualising an emerging professional identity and for directing learning towards the domains of 'self as professional' [4, 5].     

Restructuring Primary Health Care Markets in New Zealand: from Welfare Benefits to Insurance Markets

Background

New Zealand's Primary Health Care Strategy (NZPHCS) was introduced in 2002. Its features are substantial increases in government funding delivered as capitation payments, and newly-created service-purchasing agencies. The objectives are to reduce health disparities and to improve health outcomes.

Analysis

The NZPHCS changes New Zealand's publicly-funded primary health care payments from targeted welfare benefits to universal, risk-rated insurance premium subsidies. Patient contributions change from fee-for-service top-ups to insurance premium top-ups, and are collected by service providers who, depending upon their contracts with purchasers, may also be either insurance agents or risk-bearing insurance companies. The change invokes the tensions associated with allocating risk-bearing amongst providers, patients and insurance companies that accompany all insurance-based funding instruments. These include increases in existing incentives for over-consumption and new incentives for insurers to limit their exposure to variations in patient health states by engaging in active patient pool selection.The New Zealand scheme is complex, but closely resembles United States insurance-based, risk-rated managed care schemes. The key difference is that unlike classic managed care models, where provider remuneration is determined by the insurer, the historic right for general practitioners to autonomously set patient charges alters the fiscal incentives normally available to managed care organisations. Consequently, the insurance role is being devolved to individual service providers with very small patient pools, who must recoup the premium top-ups from insured individuals. Premium top-ups are being collected only from those individuals consuming care, in proportion to the number of times care is sought. Co-payments thus constitute perfectly risk-rated premium levies set by inefficiently small insurers, raising questions about the efficiency and equity of a 'universal' insurance system pooling total population demands and costs. The efficacy of using financial incentives to constrain costs and encourage innovation when providers retain the right to arbitrarily recoup costs directly from patients, is also questioned.

Results

Initial evidence suggests that total costs are higher than initially expected, and prices to some patients have risen substantially under the NZPHCS. Limited competition and NZPHCS governance requirements mean current institutional arrangements are unlikely to facilitate efficiency improvements. System design changes therefore appear indicated.

     

Screening for Depression in the Medically Ill: a comparison of self-report measures, clinician judgment, and DSM-IV diagnoses

The performance of the self-report 10-item Depression in the Medically Ill scale was observed in 210 patients as part of clinical assessment by consultation-liaison psychiatry clinicians. Both the Depression in the Medically Ill scale and the Beck Depression Inventory for Primary Care were completed by the patient, and the clinicians made their judgment of the presence and severity of "clinical depression" and DSM-IV affective disorder diagnoses. Both the Depression in the Medically Ill scale and the Beck Depression Inventory for Primary Care detected 85% of patients with DSM-IV major depressive episode. The Depression in the Medically Ill scale was slightly superior to the Beck Depression Inventory for Primary Care in its relationship to clinicians' judgments of clinical depression caseness.     

Nonlinear and Frequency-Dependent Mechanical Behavior of the Mouse Respiratory System

The assessment of the mechanical properties of the respiratory system is typically done by oscillating flow into the lungs via the trachea, measuring the resulting pressure generated at the trachea, and relating the two signals to each other in terms of some suitable mathematical model. If the perturbing flow signal is broadband and not too large in amplitude, linear behavior is usually assumed and the input impedance calculated. Alternatively, some researchers have used flow signals that are narrow band but large in amplitude, and invoked nonlinear lumped-parameter models to account for the relationship between flow and pressure. There has been little attempt, however, to deal with respiratory data that are both broadband and reflective of system nonlinearities. In the present study, we collected such data from mice. To interpret these data, we first developed a time-domain approximation to a widely used model of respiratory input impedance. We then extended this model to include nonlinear resistive and elastic terms. We found that the nonlinear elastic term fit the data better than the linear model or the nonlinear resistance model when amplitudes were large. This model may be useful for detecting overinflation of the lung during mechanical ventilation. © 2003 Biomedical Engineering Society. PAC2003: 8719Rr, 8719Uv     

Comparative study on deletions of the dystrophin gene in three Asian populations

The frequency and distribution of deletions of 19 deletion-prone exons clustered in two hot spots in the proximal and central regions of the dystrophin gene were compared in three populations from Singaporean, Japan, and Vietnam. DNA samples obtained from 105 Singaporean, 86 Japanese, and 34 Vietnamese Duchenne muscular dystrophy patients were examined by polymerase chain reaction amplification. Deletions of the examined exons were found in 51.2% of Japanese patients but in 40.0% or less of the Singaporeans and Vietnamese. About two thirds of the deletions were localized in the central region and the remaining deletions were clustered at the proximal region. The most commonly deleted exons at the central deletion hot spot were exon 50 in the Singaporean, exons 49 and 50 in the Japanese, and exon 51 in the Vietnamese population. At the proximal deletion hot spot, the most commonly deleted exons were exons 6 and 8 in the Singaporeans, exons 12 and 17 in the Japanese, and exons 8 and 12 in the Vietnamese. Two cases each from Singapore and Japan had large-scale gross mutations spanning both deletion hot spots. Our results suggest that, although the presence and frequency of the two deletion hot spots may be similar in the three Asian populations analyzed, the distribution and frequency of deletions among the different exons can vary as a result of population-specific intronic sequences that predispose individuals to preferential deletion breakpoints. Received: May 20, 2002 / Accepted: July 1, 2002     

Discrimination of single-copy IS6110 DNA fingerprints of Mycobacterium tuberculosis isolates by high-resolution minisatellite-based typing

Seven isoniazid-resistant isolates with mutations in the NADH dehydrogenase (ndh) gene were molecularly typed by IS6110-based restriction fragment length polymorphism analysis. All seven isolates with the R268H mutation had identical 1.4-kb IS6110 fingerprints. High-resolution minisatellite-based typing discriminated five of these isolates; two isolates were identical.