缝隙连接在血管内皮和平滑肌细胞中的作用及其与高血压的关系

细胞间的直接通讯--缝隙连接在控制和协调血管功能方面起重要作用。缝隙连接是沟通相邻细胞质膜的唯一一类通道,为离子、小分子代谢物质、第二信使等细胞间信号分子的直接交换提供一个通道。血管内皮细胞和平滑肌细胞表达多种类型缝隙连接蛋白(connexin,Cx),多种Cx 在心血管系统中的共同表达并协调一致地工作,对心血管系统的发育、平滑肌和内皮细胞功能的整合、以及对血管壁细胞功能协调等起着重要作用。在血管发生疾病时Cx表达相应发生改变,以与缝隙连接调节血管紧张度和动脉血压的作用相一致。本综述讨论了在血管内皮和平滑肌细胞在生理和病理情况下(以高血压为例)缝隙连接对血管结构和功能的影响。     

Posterior Femoral Condylar Offset After Total Knee Replacement in The Risk of Knee Flexion Contracture

The aim of this study was to clarify the risk of knee flexion contracture associated with a posterior femoral condylar offset after total knee replacement (TKR). Radiographs from 100 healthy Japanese volunteers were included in the study. We evaluated femoral component posterior offset in various implants and compared them with the normal Japanese knee. Posterior offset of the femoral condyle is up to a maximum of 4.7 times greater than that of the healthy Japanese knee in all knee implants. Excess posterior offset of the femoral condyle in TKR prostheses may cause knee joint flexion contracture due to the relative shortening of the posterior soft tissue.     

Influence of internal-gap width and cement type on the retentive force of zirconia copings in pullout testing

Objectives

The purpose of this study was to evaluate the influence of internal-gap width and cement type on the retentive force of zirconia copings.

Methods

A CAD/CAM system was used to mill 48 identical abutments on extracted human molars and fabricate 48 zirconia copings. The internal-gap width for cement was set to 40 μm or 160 μm (n = 24 each). Three cement types (Panavia F, RelyX Unicem, and RelyX Luting) were used with each internal-gap width (n = 8/cement type). The intaglio surfaces of the copings were airborne-particle abraded, and each coping was cemented onto the corresponding abutment using the indicated luting agent. After 10,000 cycles of thermocycling, the retentive force was evaluated by pullout tests. Kruskal–Wallis and Wilcoxon Rank Sum tests were used for data analysis (α = 0.05).

Results

In the 40-μm gap groups, Panavia F had the highest mean retentive force compared to RelyX Unicem and RelyX Luting (P < 0.000). In 160-μm gap groups, RelyX Unicem had the highest mean retentive force compared to Panavia F and RelyX Luting (P < 0.000).

Conclusions

With the increase in internal gap width, a resin cement with self-etching agents as a co-initiator for autopolymerization resulted in significantly decreased retentive force, whereas a resin-modified glass ionomer cement or a self-adhesive resin cement did not. Use of resin cements rather than resin-modified glass ionomer cements improved the retentive force of zirconia copings regardless of the amount of internal gap width.     

Cross-sectional analysis of the implant-abutment interface

The purpose of this study was to develop a technique to evaluate the implant-abutment gap of an external hexagon implant system as a function of radius. Six implants of 3.75 mm in diameter (Conexao Sistema de Protese Ltda, Sao Paulo, Brazil) and their respective abutments were screw connected and torqued to 20 N cm(-1). The implants were mounted in epoxy assuring an implant long-axis position perpendicular to the vertical axis. Each implant was grounded through its thickness parallel to implant long-axis at six different distance interval. Implant-abutment gap distances were recorded along the implant-abutment region for each section. Individual measurements were related to their radial position through trigonometric inferences. A sixth degree polynomial line fit approach determined radial adaptation patterns for each implant. Micrographs along implant sections showed a approximately 300 mum length implant-abutment engagement region. All implants presented communication between external and internal regions through connection gaps and inaccurate implant-abutment alignment. Average gap distances were not significantly different between implants (P > 0.086). Polynomial lines showed implant-abutment gap values below 10 mum from 0 mum to approximately 250 mum of the implant-abutment engagement region. Gap distances significantly increased from approximately 250 mum to the outer radius of the implant-abutment engagement region. The technique described provided a broader scenario of the implant-abutment gap adaptation compared with previous work concerning implant-abutment gap determination, and should be considered for better understanding mechanical aspects or biological effects of implant-abutment adaptation on peri-implant tissues.     

Gap Balancing Sacrifices Joint-Line Maintenance to Improve Gap Symmetry: A Randomized Controlled Trial Comparing Gap Balancing and Measured Resection

A total knee arthroplasty can be completed using two techniques; measured resection or gap balancing. A prospective blinded randomized controlled trial was completed with 103 patients randomized to measured resection (n=52) or gap balancing (n=51). Primary outcome measure was femoral component rotation. Secondary outcome measures were joint-line change, gap symmetry and function and quality-of-life outcomes. Gap balancing resulted in a significantly raised joint-line compared to measured resection. Gap symmetry was significantly better using gap balancing. Functional outcomes and quality-of-life were not significantly different at 24 months. Using computer navigation, gap balancing significantly raises the joint-line in order to improve gap symmetry. This does not result in a clinical difference in function or quality of life at 24 months.     

The lived experiences of racial bias for Black,Asian and Minority Ethnic students in practice: A hermeneutic phenomenological study

AimThis study explored the lived experiences of racial bias for Black, Asian and Minority Ethnic students undertaking an undergraduate or post-graduate degree in nursing, midwifery and allied health courses in the United Kingdom.BackgroundPrevious research indicates that students from Black, Asian and Minority Ethnic groups have fewer opportunities to succeed at university and this has brought about a race awarding gap in their degree attainment. The reasons for this awarding gap are complex and multi-factorial and it is crucial that the lived experiences of racial bias are explored from the student perspective.DesignA hermeneutic phenomenological approach was adopted to elicit individual and collective experiences in the practice environment, a mandatory component of the student’s degree.MethodsA focus group and individual semi-structured interviews were conducted to collect data from sixteen participants and analysed using thematic analysisResultsThree encompassing themes were identified which included a sense of not belonging, trauma impact on mental health and understanding covert and overt racism. Participants reported incidences of racism and appeared to be traumatised by their experiences within practice and the university. They also reported poor mental health and well-being as shared experiences and a lack of confidence in the university and practice to mitigate racial issues.ConclusionsMeaningful action must be taken by universities and practice partners to advance racial inequality initiatives by having robust anti-racism action plans and processes. These should be co-created with students and staff to reduce the race awarding gap.     

Widening the participation gap: The effect of educational track on reported voting in England

This article explores the effect of tracked education in upper secondary on voting behaviour. It discusses two causal mechanisms that link tracked education to greater disparities of political participation: the curriculum and peer socialization. Data of Waves 1, 2, 5 and 7 of the Longitudinal Study of Young People in England (LSYPE) is used to assess the hypothesis that educational track has an independent effect on voting. Controlling for several pre- and post-track influences, the paper shows that students who have taken vocational courses in less prestigious schools indeed have lower reported voting levels at age 20 than those who have pursued an academic qualification (A levels) in prestigious schools. It is proposed that the effect of tracked education on political participation is likely to vary across Europe and that this variation may well be explained by differences across Europe in the extent to which the academic and vocational tracks are integrated, both in terms of the curriculum and in their social intake.     

Difficult esophageal atresia: Trick and treat

Although most patients with esophageal atresia (EA) and tracheo-esophageal fistula (TEF) may benefit from “standard” management, which is deferred emergency surgery, some may present unexpected elements that change this paradigm. Birth weight, associated anomalies, and long gap can influence the therapeutic schedule of the patients with EA/TEF and can make their treatment tricky. As a consequence, detailed information on these aspects gives the power to develop a decision-making process as correct as possible. In this article, we will review the most important factors influencing the treatment of patients with EA/TEF and will share our experience on the diagnostic and therapeutic tips that may provide pivotal help in the management of such patients.