Tetracalcium Phosphate/Monetite/Calcium Sulfate Hemihdrate Biocement Powder Mixtures Prepared by the One-Step Synthesis for Preparation of Nanocrystalline Hydroxyapatite Biocement-Properties and In Vitro Evaluation

A modified one-step process was used to prepare tetracalcium phosphate/monetite/calcium sulfate hemihydrate powder cement mixtures (CAS). The procedure allowed the formation of monetite and calcium sulfate hemihydrate (CSH) in the form of nanoparticles. It was hypothesized that the presence of nanoCSH in small amounts enhances the in vitro bioactivity of CAS cement in relation to osteogenic gene markers in mesenchymal stem cells (MSCs). The CAS powder mixtures with 15 and 5 wt.% CSH were prepared by milling powder tetracalcium phosphate in an ethanolic solution of both orthophosphoric and sulfuric acids. The CAS cements had short setting times (around 5 min). The fast setting of the cement samples after the addition of the liquid component (water solution of NaH₂PO₄) was due to the partial formation of calcium sulfate dihydrate and hydroxyapatite before soaking in SBF with a small change in the original phase composition in cement powder samples after milling. Nanocrystalline hydroxyapatite biocement was produced by soaking of cement samples after setting in simulated body fluid (SBF). The fast release of calcium ions from CAS5 cement, as well as a small rise in the pH of SBF during soaking, were demonstrated. After soaking in SBF for 7 days, the final product of the cement transformation was nanocrystalline hydroxyapatite. The compressive strength of the cement samples (up to 30 MPa) after soaking in simulated body fluid (SBF) was comparable to that of bone. Real time polymerase chain reaction (RT-PCR) analysis revealed statistically significant higher gene expressions of alkaline phosphatase (ALP), osteonectin (ON) and osteopontin (OP) in cells cultured for 14 days in CAS5 extract compared to CSH-free cement. The addition of a small amount of nanoCSH (5 wt.%) to the tetracalcium phosphate (TTCP)/monetite cement mixture significantly promoted the over expression of osteogenic markers in MSCs. The prepared CAS powder mixture with its enhanced bioactivity can be used for bone defect treatment and has good potential for bone healing.     

Effect of Calcium Nitrate on the Properties of Portland–Limestone Cement-Based Concrete Cured at Low Temperature

The effect of calcium nitrate (CN) dosages from 0 to 3% (of cement mass) on the properties of fresh cement paste rheology and hardening processes and on the strength of hardened concrete with two types of limestone-blended composite cements (CEM II A-LL 42.5 R and 42.5 N) at different initial (two-day) curing temperatures (−10 °C to +20 °C) is presented. The rheology results showed that a CN dosage up to 1.5% works as a plasticizing admixture, while higher amounts demonstrate the effect of increasing viscosity. At higher CN content, the viscosity growth in normal early strength (N type) cement pastes is much slower than in high early strength (R type) cement pastes. For both cement-type pastes, shortening the initial and final setting times is more effective when using 3% at +5 °C and 0 °C. At these temperatures, the use of 3% CN reduces the initial setting time for high early strength paste by 7.4 and 5.4 times and for normal early strength cement paste by 3.5 and 3.4 times when compared to a CN-free cement paste. The most efficient use of CN is achieved at −5 °C for compressive strength enlargement; a 1% CN dosage ensures the compressive strength of samples at a −5 °C initial curing temperature, with high early strength cement exceeding 3.5 MPa but being less than the required 3.5 MPa in samples with normal early strength cement.     

Cost-effectiveness of Molecular Profile Patient Selection for First-line Treatment of Recurrent/Metastatic Head and Neck Cancer

PurposePatients with recurrent and/or metastatic head and neck squamous cell cancer are offered platinum-based chemotherapy plus cetuximab; however, this strategy is not cost-effective. We evaluated the cost-effectiveness of a hypothetical predictive molecular test to identify and treat only patients potentially responsive to cetuximab (C) added to platinum-fluorouracil (PF) (PF + C POS) versus the administration of PF + C to all patients (PF + C ALL).MethodsA Markov model has been developed to estimate health outcomes (quality-adjusted life years [QALYs]; life years [LYs]) and costs of the 2 strategies on a time horizon of 3 years from the Italian health care perspective. For the response to treatment, a definition, including partial or complete response, has been applied. In the base-case scenario, molecular test sensitivity, specificity, and cost have been assumed equal to 85%, 70%, and €4000, respectively.FindingsThe model estimated 0.5285 QALYs (0.9245 LYs) and 0.5666 QALYs (0.9949 LYs) for PF + C POS and PF + C ALL, respectively. The incremental cost-utility ratio of PF + C ALL versus PF + C POS was €112,462/QALY, suggesting the administration of PF + C only to patients who would be responsive to it.ImplicationsThe use of cetuximab with chemotherapy could be a cost-effective choice in first-line recurrent and/or metastatic head and neck squamous cell cancer if based on a molecular selection able to identify which patients will achieve partial or complete response to the treatment. The developed model may be usefully applied to new emerging treatments, such as immunotherapeutic agents in the same setting.     

A priority dispatch system for emergency medical services

A decision tree priority dispatch system for emergency medical services (EMS) was developed and implemented in Atlanta and Fulton County, Georgia. The dispatch system shortened the average response time from 14.2 minutes to 10.4 minutes for the 30% of patients deemed most urgent (P less than or equal to .05); resulted in a significant increase in the use of advanced life support units for this group (P less than or equal to .02); decreased the number of calls that required a backup ambulance service; and significantly increased conformity to national EMS response time standards for critically ill and injured patients (P less than or equal to .0009). Due to dispatch error, 0.3% of calls were dispatched as least severe but subsequently were found to be most urgent.     

军医大学选修课程体系管理

优质的选修课程可以激发学员的兴趣和学习主动性,拓宽学员的知识面。完善选修课程体系,提升课程管理水平是适应现代医学院校高等教育体系改革,实现军队医学院校人才培养目标的重要支撑和有效途径。要明晰选修课程与必修课程在医院院校课程体系中的共同支撑地位和相互关联性,课程设置要注意围绕军队医学人才培养目标的实现要求、注重发挥选修课的基本功能和满足学员的实际需求,课程的管理应具有灵活性。在遵循自主选课原则基础上,实行学分制及中途退续课机制,并辅以严格的考核制度。     

PRIORITY SETTING IN GLOBAL HEALTH: TOWARDS A MINIMUM DALY VALUE

Rational and analytic healthcare decision making employed by many national healthcare‐funding bodies could also be expected from global health donors. Cost effectiveness analysis of healthcare investment options presents the effectiveness of a particular action in proportion to the resources required, and cost effectiveness thresholds, while somewhat arbitrary, define the level at which the investment can be considered value for money. Currently, cost effectiveness thresholds reflect the national budget context or willingness‐to‐pay, which is problematic when making cross‐country comparisons. Defining a global minimum monetary value for the disability adjusted life year (DALY) would in effect set a global baseline cost effectiveness threshold. A global minimum DALY value would reflect a universal minimum value on human health, irrespective of a national provider's willingness or ability to pay. A minimum DALY value and associated threshold has both limitations and flaws but is justified on similar grounds to the Millennium Development Goals or the absolute poverty threshold and has the potential to radically improve transparency and efficiency of priority setting in global health. Copyright © 2013 John Wiley & Sons, Ltd.     

To accept,or not to accept,that is the question: citizen reactions to rationing

Background The publicly financed health service in Sweden has come under increasing pressure, forcing policy makers to consider restrictions. Objective To describe different perceptions of rationing, in particular, what citizens themselves believe influences their acceptance of having to stand aside for others in a public health service. Design Qualitative interviews, analysed by phenomenography, describing perceptions by different categories. Setting and participants Purposeful sample of 14 Swedish citizens, based on demographic criteria and attitudes towards allocation in health care. Results Participants expressed high awareness of limitations in public resources and the necessity of rationing. Acceptance of rationing could increase or decrease, depending on one’s (i) awareness that healthcare resources are limited, (ii) endorsement of universal health care, (iii) knowledge and acceptance of the principles guiding rationing and (iv) knowledge about alternatives to public health services. Conclusions This study suggests that decision makers should be more explicit in describing the dilemma of resource limitations in a publicly funded healthcare system. Openness enables citizens to gain the insight to make informed decisions, i.e. to use public services or to ‘opt out’ of the public sector solution if they consider rationing decisions unacceptable.