Laser and electron‐beam powder‐bed additive manufacturing of metallic implants: A review on processes,materials and designs

Additive manufacturing (AM), also commonly known as 3D printing, allows the direct fabrication of functional parts with complex shapes from digital models. In this review, the current progress of two AM processes suitable for metallic orthopaedic implant applications, namely selective laser melting (SLM) and electron beam melting (EBM) are presented. Several critical design factors such as the need for data acquisition for patient‐specific design, design dependent porosity for osteo‐inductive implants, surface topology of the implants and design for reduction of stress‐shielding in implants are discussed. Additive manufactured biomaterials such as 316L stainless steel, titanium‐6aluminium‐4vanadium (Ti6Al4V) and cobalt‐chromium (CoCr) are highlighted. Limitations and future potential of such technologies are also explored. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:369–385, 2016.     

Pannexin‐1 and P2X7‐Receptor Are Required for Apoptotic Osteocytes in Fatigued Bone to Trigger RANKL Production in Neighboring Bystander Osteocytes

Osteocyte apoptosis is required to induce intracortical bone remodeling after microdamage in animal models, but how apoptotic osteocytes signal neighboring “bystander” cells to initiate the remodeling process is unknown. Apoptosis has been shown to open pannexin‐1 (Panx1) channels to release adenosine diphosphate (ATP) as a “find‐me” signal for phagocytic cells. To address whether apoptotic osteocytes use this signaling mechanism, we adapted the rat ulnar fatigue‐loading model to reproducibly introduce microdamage into mouse cortical bone and measured subsequent changes in osteocyte apoptosis, receptor activator of NF‐κB ligand (RANKL) expression and osteoclastic bone resorption in wild‐type (WT; C57Bl/6) mice and in mice genetically deficient in Panx1 (Panx1KO). Mouse ulnar loading produced linear microcracks comparable in number and location to the rat model. WT mice showed increased osteocyte apoptosis and RANKL expression at microdamage sites at 3 days after loading and increased intracortical remodeling and endocortical tunneling at day 14. With fatigue, Panx1KO mice exhibited levels of microdamage and osteocyte apoptosis identical to WT mice. However, they did not upregulate RANKL in bystander osteocytes or initiate resorption. Panx1 interacts with P2X₇R in ATP release; thus, we examined P2X₇R‐deficient mice and WT mice treated with P2X₇R antagonist Brilliant Blue G (BBG) to test the possible role of ATP as a find‐me signal. P2X₇RKO mice failed to upregulate RANKL in osteocytes or induce resorption despite normally elevated osteocyte apoptosis after fatigue loading. Similarly, treatment of fatigued C57Bl/6 mice with BBG mimicked behavior of both Panx1KO and P2X₇RKO mice; BBG had no effect on osteocyte apoptosis in fatigued bone but completely prevented increases in bystander osteocyte RANKL expression and attenuated activation of resorption by more than 50%. These results indicate that activation of Panx1 and P2X₇R are required for apoptotic osteocytes in fatigued bone to trigger RANKL production in neighboring bystander osteocytes and implicate ATP as an essential signal mediating this process. © 2016 American Society for Bone and Mineral Research.     

A follow-up study of women who donated oocytes to known recipient couples for altruistic reasons

BACKGROUND: Current legislation in Canada allows for only altruistic gamete donation. Limited clinical data are available on the emotional and psychological impact of altruistic oocyte donation on known donors. METHODS: Seventeen women who had donated oocytes to known parties without financial compensation agreed to receive the oocyte donation questionnaire (ODQ) to explore the psychological domains of altruistic oocyte donation. RESULTS: Thirteen ODQ were returned, giving a response rate of 76%. All subjects indicated that they were primarily motivated by a 'desire to give and help' the recipient couple. Most subjects did not find the donation decision difficult but some found the post-donation psychological adjustments challenging. Subjects also indicated that mandatory counselling on the psychological implications of oocyte donation was an important component of cycle preparation. The majority of subjects had disclosed the donation to others and felt that disclosure to the presumptive child was essential. CONCLUSIONS: The findings provide clinical materials for conceptualizing the dynamics entailed by known altruistic oocyte donation, with regards to motivation, relationship implications, donor satisfaction and plans for disclosure. The data support the provision of psycho-social support services to help donors dealing with any residual emotional difficulties regardless of the outcome of oocyte donation.     

A global perspective on changes in the burden of caries and periodontitis: implications for dentistry

The structure and contents of most oral health care systems and the contents of dental curricula reflect a deep-rooted tradition for attempting to cure oral diseases by refined technological means. However, better oral health conditions for the world's populations necessitate the application of up-to-date scientific knowledge to control the major oral diseases. This review points out that not only should the structure and contents of oral health care delivery systems be based on state-of-the-art knowledge about the biology of the oral diseases; they must also take into account the trends for change in caries and periodontal diseases within and between populations, and acknowledge the impact of changes in treatment philosophies for these trends. The oral disease profiles for populations in low- and high-income countries are briefly described, and it is concluded that the rapidly changing disease profiles observed in high-income countries necessitate re-thinking of the future role and organization of dentistry in such countries. The priorities for low- and middle-income countries must be to avoid repeating the mistakes made in the high-income countries. Instead, these societies might take advantage of setting priorities based on a population-based common risk factor approach. If such an approach is adopted, the training of personnel with oral health care competence must be rethought. The authors suggest three different cadres of dental care providers to be considered for an approach that allows health care planners in different populations around the world to prioritize appropriate oral health care with due respect for the socio-economic conditions prevailing.     

Management of acute intra-abdominal hemorrhage in ruptured hepatoblastoma with transarterial embolization using calibrated gelfoam particles

This brief report aims to evaluate the treatment outcome of transarterial embolization in ruptured hepatoblastoma complicated with acute intra-abdominal hemorrhage. Three children (mean age 6 years) with high-risk hepatoblastoma presented with rupture and acute intra-abdominal hemorrhage. In addition to aggressive fluid resuscitation and blood product support, super-selective embolization of the arteries with active bleeding or pseudoaneurysm was performed using calibrated gelfoam particles, with a technical success rate of 100%. Hemodynamic status and hemoglobin level were normalized in all patients within 2 days postembolization. The 30-day survival rate was 100%. No major complication was detected apart from mild elevation of alanine transaminase.     

Comparing Effectiveness of High-Fidelity Human Patient Simulation vs Case-Based Learning in Pharmacy Education

Objective. To determine whether human patient simulation (HPS) is superior to case-based learning (CBL) in teaching diabetic ketoacidosis (DKA) and thyroid storm (TS) to pharmacy students.Design. In this cross-over, open-label, single center, randomized control trial, final-year undergraduate pharmacy students enrolled in an applied therapeutics course were randomized to HPS or CBL groups. Pretest, posttest, knowledge retention tests, and satisfaction survey were administered to students.Assessment. One hundred seventy-four students participated in this study. The effect sizes attributable to HPS were larger than CBL in both cases. HPS groups performed significantly better in posttest and knowledge retention test compared to CBL groups pertaining to TS case (p<0.05). Students expressed high levels of satisfaction with HPS sessions.Conclusion. HPS was superior to CBL in teaching DKA and TS to final-year undergraduate pharmacy students.