Advocating for Policy Change: Examples Emerging From a Medical-Legal Partnership in Primary Care.

Medical-legal partnerships bring legal services directly into clinical settings. Policy advocacy is often opportunistic and varies across partnerships. Our objective was to study policy advocacy that emerged from a medical-legal partnership in Toronto over a four-year period.

Integrating social justice advocacy into a family health team: Successes and lessons learned.

Problem Addressed: Health is largely determined by socioeconomic factors. Health care providers can potentially address these factors through social justice advocacy. However, many individual providers and teams have not taken on this role in Canada.

End-systolic Pressure-Volume Relation, Ejection Fraction, and Heart Failure: Theoretical Aspect and Clinical Applications.

A mathematical formalism describing the nonlinear end-systolic pressure-volume relation (ESPVR) is used to derive new indexes that can be used to assess the performance of the heart left ventricle by using the areas under the ESPVR (units of energy), the ordinates of the ESPVR (units of pressure), or from slopes of the curvilinear ESPVR. New relations between the ejection fraction (EF) and the parameters describing the ESPVR give some insight into the problem of heart failure (HF) with normal or preserved ejection fraction. Relations between percentage occurrence of HF and indexes derived from the ESPVR are also discussed.

Investigating pharmaceutical marketing in Canada using American prosecutions.

Background: Pharmaceutical companies are prohibited from marketing medications for off-label uses in both the United States and Canada. In the United States, there have been several recent multi-billion dollar settlements with pharmaceutical companies based, partly, on off-label promotion. Health Canada has not publicized any investigations into, or prosecutions of, pharmaceutical companies for off-label promotion in Canada even though many of the same medications are marketed here.

Ejection Fraction and ESPVR. A study from a theoretical perspective.

A formula derived by using large elastic deformation for the contraction of the myocardium is used to describe the pressure-volume relation (PVR) in the heart left ventricle, it is also used to calculate a mathematical expression for the non-linear end-systolic pressure-volume relation (ESPVR) in the left ventricle. An important feature of the mathematical formalism used is the inclusion of the isovolumic pressure Piso (equal active pressure generated by the myocardium) in the formalism describing the PVR. Relations between the ejection fraction (EF) and parameters describing the non-linear ESPVR are presented.

Criteria for study of heart failure derived from ESPVR.

In this study, the end-systolic pressure-volume relation (ESPVR) is used to derive new criteria that can help understand the problem of heart failure with normal or preserved ejection fraction (HFpEF). It is shown that the ejection fraction (EF) is just one index of several indexes that can be derived from the parameters describing the ESPVR and related areas under ESPVR.

ESPVR, ejection fraction and heart failure.

The problem of heart failure with preserved ejection fraction (HFpEF) has recently received much attention. In this study we discuss some relations that connect ejection fraction EF to the parameters describing the end-systolic pressure-volume relation (ESPVR). It is shown that the study of the relation between EF and ESPVR can give some understanding of the problem of HFpEF.

Application of the method of characteristics for the study of shock waves in models of blood flow in the aorta.

Numerical algorithms are presented for the numerical solution of the one-dimensional model of blood flow in the aorta. The pertinent hyperbolic equations are written using Riemann invariants, which are integrated along the characteristics using two efficient algorithms. Because of the hyperbolic nature of the equations shock waves are to be expected, and their occurrence is discussed.

Analysis of the cruciform binding activity of recombinant 14-3-3zeta-MBP fusion protein, its heterodimerization profile with endogenous 14-3-3 isoforms, and effect on mammalian DNA replication in vitro.

The human cruciform binding protein (CBP), a member of the 14-3-3 protein family, has been recently identified as an origin of DNA replication binding protein and involved in DNA replication. Here, pure recombinant 14-3-3zeta tagged with maltose binding protein (r14-3-3zeta-MBP) at its N-terminus was tested for binding to cruciform DNA either in the absence or presence of F(TH), a CBP-enriched fraction, by electromobility shift assay (EMSA), followed by Western blot analysis of the electroeluted CBP-cruciform DNA complex. The r14-3-3zeta-MBP was found to have cruciform binding activity only after preincubation with F(TH).

The calculation of the intramyocardial stress.

A mathematical approach is given by which the intramyocardial stress sigma induced in the passive medium of the myocardium is expressed as the sum of the stress (sigma)p induced in the passive medium by the left ventricular pressure P and the external pressure Po, and the stress(sigma)d induced in the passive medium by the active force generated by the muscular fibers of the myocardium. Relations between sigma = (sigma)p + (sigma)d, the left ventricular elastance E and the residual volume Vd are also derived. Applications to experimental data are given and clinical implications of the results are discussed.

Active and passive stresses in the myocardium.

A mathematical approach that can be used to calculate the passive stress in the ventricular wall is presented. The active fiber stress (force/unit area) generated by the muscular fibers in the ventricular wall is expressed by means of body force (force/unit volume of the myocardium). It is shown that the total intramyocardial passive stress induced in the passive medium of the myocardium can be expressed as the sum of a passive stress induced by the left ventricular pressure and a passive stress induced by the active fiber stress.

Studying the mechanics of left ventricular contraction.

Several interesting aspects of the ESPVR have been discussed in this study, including: a) A possibility to introduce, in an explicit manner, the active force of the myocardium in the formalism describing the PVR of the left ventricle. b) A possibility to express the ventriculo-arterial coupling by using the ratio Emax/eam in a way to distinguish between the normal physiological state and the mildly or severely depressed state of the heart. The possibility of also expressing this coupling by using directly different areas under ESPVR has been indicated.

Ventriculo-arterial coupling and the areas under the end-systolic pressure-volume relation.

Ventriculo-arterial coupling is expressed as the ratio Emax/eam (maximum ventricular elastance/arterial elastance). Different areas under the end-systolic pressure-volume relation (ESPVR) are expressed in terms of Emax/eam. The explicit inclusion of the active force of the myocardium in the mathematical formalism describing the pressure-volume relation (PVR) leads to new insight into the mechanics of left ventricular contraction.

Possible clinical applications of the external work reserve of the myocardium.

The concept of external work reserve (EWR) related to the end-systolic pressure-volume relation in the left ventricle and introduced in previous publications is investigated. The potential clinical usefulness of indexes related to EWR as well as to different areas under the end-systolic pressure volume line (ESPVL) is indicated. The possibility of non-invasive clinical application of the results of this study is discussed.

Clinical application of end-systolic pressure-volume relation.

On the basis of a mathematical formalism derived in previous studies, properties of the end-systolic pressure-volume (P-V) relation were analyzed to define indexes that can characterize a normal or failing left ventricle. Careful analysis of different areas under the P-V line can lead to new indexes that describe the performance of the left ventricle. The possibility to distinguish between normal, mildly depressed, or severely depressed left ventricles based on P-V relation is discussed.

Theoretical study related to left ventricular energetics.

This study presents new mathematical relations to link oxygen consumption to different areas under the end-systolic pressure-volume relation (ESPVR). The approach consists of approximating the relation between oxygen consumption and left ventricular pressure by a quadratic polynomial, and then relating the coefficients of the quadratic polynomial to different areas under the ESPVR. The procedure applies to both ejecting contraction and isovolumic contraction.

Pressure-volume relation in the right ventricle.

The concept of body force (force/unit volume of muscle), which has been suggested as an explanation for the mechanical contraction of the left ventricle, is now applied to the right ventricle. The results indicate that the same mathematical formalism can be applied to a description of the pressure-volume relation and the ejection mechanism in both the right and left ventricles.

Pump function of the heart as an optimal control problem.

In order to model the pump function of the heart the left ventricle is represented as an elastic thick-walled cylinder contracting symmetrically. The acceleration is included in the mathematical formalism describing the contraction of the myocardium and optimal control theory is used to solve the differential equation of motion of the cylindrical wall in such a way as to minimize a given performance index. Application of the equations to experimental data published in the literature is discussed.

Non-linear pressure-volume relation in left ventricle.

A thick-walled elastic cylinder contracting symmetrically is used as a model for the myocardium. The active force generated by the myocardium during systolic contraction is represented by body force (force/unit volume of myocardium). A mathematical formalism previously developed and based on large deformation analysis is used to derive a quadratic equation to represent the non-linear pressure volume (P-V) relation in the left ventricle in the Suga-Sagawa model.