Immigration Status and Breast Cancer Surgery Quality of Care Metrics: A Population-Level Analysis.

INTRODUCTION: As immigrant women face challenges accessing health care, we hypothesized that immigration status would be associated with fewer women with breast cancer receiving surgery for curable disease, fewer undergoing breast conserving surgery (BCS), and longer wait time to surgery. METHODS: A population-level retrospective cohort study, including women aged 18-70 years with Stage I-III breast cancer diagnosed between 2010 and 2016 in Ontario was conducted. Multivariable analysis was performed to assess odds of undergoing surgery, receiving BCS and wait time to surgery. RESULTS: A total of 31,755 patients were included [26,253 (82.7%) Canadian-born and 5502 (17.3%) immigrant women]. Immigrant women were younger (mean age 51.6 vs. 56.1 years) and less often presented with Stage I/II disease (87.4% vs. 89.8%) (both p < .001). On multivariable analysis, there was no difference between immigrant women and Canadian-born women in odds of undergoing surgery [Stage I OR 0.93 (95% CI 0.79-1.11), Stage II 1.04 (0.89-1.22), Stage III 1.22 (0.94-1.57)], receiving BCS [Stage I 0.93 (0.82-1.05), Stage II 0.96 (0.86-1.07), Stage III 1.00 (0.83-1.22)], or wait time [Stage I 0.45 (-0.61-1.50), Stage II 0.33 (-0.86-1.52), Stage III 3.03 (-0.05-6.12)]. In exploratory analysis, new immigrants did not have surgery more than established immigrants (12.9% vs. 10.1%), and refugee women had longer wait time compared with economic-class immigrants (39.5 vs. 35.3 days). CONCLUSIONS: We observed differences in measures of socioeconomic disadvantage and disease characteristics between immigrant and Canadian-born women with breast cancer. Upon adjusting for these factors, no differences emerged in rate of surgery, rate of BCS, and time to surgery. The lack of disparity suggests barriers to accessing basic components of breast cancer care may be mitigated by the universal healthcare system in Canada.

A Review of Recent Advances in 3D Bioprinting With an Eye on Future Regenerative Therapies in Veterinary Medicine.

3D bioprinting is a rapidly evolving industry that has been utilized for a variety of biomedical applications. It differs from traditional 3D printing in that it utilizes bioinks comprised of cells and other biomaterials to allow for the generation of complex functional tissues. Bioprinting involves computational modeling, bioink preparation, bioink deposition, and subsequent maturation of printed products; it is an intricate process where bioink composition, bioprinting approach, and bioprinter type must be considered during construct development. This technology has already found success in human studies, where a variety of functional tissues have been generated for both in vitro and in vivo applications. Although the main driving force behind innovation in 3D bioprinting has been utility in human medicine, recent efforts investigating its veterinary application have begun to emerge. To date, 3D bioprinting has been utilized to create bone, cardiovascular, cartilage, corneal and neural constructs in animal species. Furthermore, the use of animal-derived cells and various animal models in human research have provided additional information regarding its capacity for veterinary translation. While these studies have produced some promising results, technological limitations as well as ethical and regulatory challenges have impeded clinical acceptance. This article reviews the current understanding of 3D bioprinting technology and its recent advancements with a focus on recent successes and future translation in veterinary medicine.

Loss of resealing ability in erythrocyte membranes. Effect of divalent cations and spectrin release.

Washed human erythrocyte membranes can recover impermeability to macromolecules upon warming in solutions of sufficient ionic strength. This ability is rapidly lost from most ghost preparations in dilute salt solution at temperatures of 15 degrees C of higher. Divalent cations both reseal ghosts in the absence of high ionic strength and prevent loss of resealing ability. The effective concentrations are 40 micron for Ca2+ and 200 micron for Mg2+. The loss of resealing ability is associated with the release of spectrin polypeptides from the inner surface of the membrane. In ghost preparations that have not become irreversibly leaky, or in the presence of Ca2+, loss of spectrin does not occur. These results suggest that an intact spectrin netwoek is required for resealing to macromolecules, and divalent cations stabilize this network. In light of this information, the effect of temperature on resealing kinetics is described.

Observations on Levitt's "new theory of transport".

Levitt (1974) (Biochim. Biophys. Acta 373, 115--131) has recently developed a "New Theory of Transport for Cell Membrane Pores" based on the supposition that equivalent pores in the red cell membrane are so small that water and small solute molecules such as urea can not pass each other. Levitt's concept is based on the implicit assumption that urea and water are spherical molecules. We have shown, using a scale model, that Levitt's supposition is not in agreement with the actual molecular shapes. Levitt has further asserted that there is a serious methodological error in measurements reported fifteen years ago by Goldstein and Solomon (1960) (J. Gen. Physiol. 44, 1--17). We have shown that the supposed "methodological error" lies in the fact that Levitt made his mathematical analysis of the appropriate equations under conditions significantly different from those employed by Goldstein and Solomon. A computer solution of the equations under the actual conditions used shows that Levitt's assertion is not justified.

Improved stop-flow apparatus to measure permeability of human red cells and ghosts.

An improved stop-flow apparatus has been designed and constructed to measure the permeability characteristics of human red cells, which can be inferred from the time course of red cell volume changes following a sudden change in cellular environment produced by a raped mixing device. The improved apparatus is directly coupled to a computer which automates the subtraction and averaging procedures that have been developed to minimize the noise generated in the system by the cessation of red cell forward motion when the flow is suddenly stopped. Real time data acquisition also makes it possible to increase the number of data points by an order of magnitude, thus improving accuracy significantly. The apparatus has been tested by measurements of the human red cell hydraulic permeability coefficient. Data are presented to validate the subtraction procedure. Experiments have also been carried out on red cell ghosts which indicate that the hydraulic conductivity of the ghost is similar to that of the undisturbed red cell.

The effect of stem geometry on stresses within the distal cement mantle in total hip replacement.

Cement-stem debonding is one of the most common reasons for failure in Total Hip Replacement (THR). Four similar THR prostheses design configurations were investigated with reference to the influence of mechanical stress occurring in a cement mantle of differing thicknesses and potentially affecting clinical performance. Non-linear finite element analysis was performed on constant cement mantle thicknesses of 1, 2, and 4 millimetres. The results obtained indicate stress levels within the cement mantle decrease with increasing cement mantle thickness. The prosthesis distal tip is shown to have particular significance. Truncation of the distal tip hemisphere to a flat profile for the fixation of a centralizer increases the cement stresses.