放射数字化减影技术(Digital Subtraction Radiography)在评估骨组织细微变化方面的应用

在口腔医学临床实践中,对及时发现早期、细微硬组织的变化提出了越来越高的要求.由于口腔颌面部硬组织结构复杂,运用常规的影像学检测手段常难以对早期病损作出准确的诊断.即使已存在明显的牙槽骨丧失,但确诊变化程度,常受种种因素干扰而发生误差.在口腔种植中,早期存在的种植体周围的碟形或角形缺损,以及沿着根状种植体螺纹的骨丧失很难在常规影像上发现.此外,对引导组织再生技术的早期效果也需精确、灵敏的评估技术.目前较常用的是依靠临床手术直视下或放射影像学观察两种方法.如使用手术方法观察,必须进行两次手术,可能会损伤新的结缔组织附着;而影像学评估则是目前最佳的非创伤性方法.因此,放射数字减影技术(Digital Subtraetion Radiography,DSR)作为具有高度敏感性的影像诊断方法逐步被应用到口腔临床医学.     

Are the ACR 2010 diagnostic criteria for fibromyalgia better than the 1990 criteria?

Fibromyalgia (FM) is difficult to diagnose and manage chronic pain condition whose symptoms have no clear pathophysiological cause, although it is thought that patient hypersensitivity to a range of stimuli may give rise to mechanical hyperalgesia as a result of altered central nociceptive processing. The 1990 American College of Rheumatology (ACR) classification criteria, which have been widely used in clinical practice, require the existence of chronic widespread pain (CWP) for > 3 months, and the presence of at least 11 out of 18 specified tender points upon digital palpation, although this latter criterion has long been criticised. The newer 2010 ACR diagnostic criteria state that FM can be defined as CWP associated with somatic symptoms, and recommend the use of a widespread pain index and a scale to rate symptom severity. A modified version of the 2010 criteria removed the physician assessment of the extent of somatic symptoms and replaced it by a summary score of three self-reported symptoms, thus making it easier to use while maintaining its sensitivity. This review discusses the advantages and limitations of all of these criteria.     

Genotype–phenotype landscapes for immune–pathogen coevolution

Our immune systems constantly coevolve with the pathogens that challenge them, as pathogens adapt to evade our defense responses, with our immune repertoires shifting in turn. These coevolutionary dynamics take place across a vast and high-dimensional landscape of potential pathogen and immune receptor sequence variants. Mapping the relationship between these genotypes and the phenotypes that determine immune–pathogen interactions is crucial for understanding, predicting, and controlling disease. Here, we review recent developments applying high-throughput methods to create large libraries of immune receptor and pathogen protein sequence variants and measure relevant phenotypes. We describe several approaches that probe different regions of the high-dimensional sequence space and comment on how combinations of these methods may offer novel insight into immune–pathogen coevolution.     

One Year’s Results from a Server-Based System for Performing Reject Analysis and Exposure Analysis in Computed Radiography

Rejected images represent both unnecessary radiation exposure to patients and inefficiency in the imaging operation. Rejected images are inherent to projection radiography, where patient positioning and alignment are integral components of image quality. Patient motion and artifacts unique to digital image receptor technology can result in rejected images also. We present a centralized, server-based solution for the collection, archival, and distribution of rejected image and exposure indicator data that automates the data collection process. Reject analysis program (RAP) and exposure indicator data were collected and analyzed during a 1-year period. RAP data were sorted both by reason for repetition and body part examined. Data were also stratified by clinical area for further investigation. The monthly composite reject rate for our institution fluctuated between 8% and 10%. Positioning errors were the main cause of repeated images (77.3%). Stratification of data by clinical area revealed that areas where computed radiography (CR) is seldom used suffer from higher reject rates than areas where it is used frequently. S values were log-normally distributed for examinations performed under either manual or automatic exposure control. The distributions were positively skewed and leptokurtic. S value decreases due to radiologic technology student rotations, and CR plate reader calibrations were observed. Our data demonstrate that reject analysis is still necessary and useful in the era of digital imaging. It is vital though that analysis be combined with exposure indicator analysis, as digital radiography is not self-policing in terms of exposure. When combined, the two programs are a powerful tool for quality assurance.     

Nanotechnology for Cell–Substrate Interactions

In the pursuit to understand the interaction between cells and their underlying substrates, the life sciences are beginning to incorporate micro- and nanotechnology-based tools to probe and measure cells. The development of these tools portends endless possibilities for new insights into the fundamental relationships between cells and their surrounding microenvironment that underlie the physiology of human tissue. Here, we review techniques and tools that have been used to study how a cell responds to the physical factors in its environment. We also discuss unanswered questions that could be addressed by these approaches to better elucidate the molecular processes and mechanical forces that dominate the interactions between cells and their physical scaffolds.     

Ankle–foot simulator development for testing ankle–foot orthoses

The fatigue failure of thermoplastic ankle–foot orthoses (AFOs) was observed in clinics. However, there was no standard evaluation for the AFOs to enhance the understanding of how AFOs become more readily acceptable to patients. Therefore, this study aimed to develop an ankle–foot simulator (AFS) as a testing apparatus for AFOs, and performed a pilot test to investigate the failure mechanism of anterior ankle–foot orthosis (AAFO). The accuracy and repeatability of the AFS during cyclic walking, cyclic stepping and cyclic stepping with the AAFO in sagittal plane were measured. The root mean square errors (RMSEs) of cyclic walking of AFS compared to a target gait data were less than 80.52N and 2.55° in the vertical ground reaction force and in the kinematics, respectively. The RMSE of ankle plantarflexion and dorsiflexion of AFS in the cyclic stepping tests were less than 1.25°. The repeatability was assessed by standard deviation, which were less than 9.46N and 0.72° in all testing conditions. A typical failure progression of five AAFOs was observed and graded for four phases under cyclic stepping test. Failure always initiated at the junction of anterior tarsal bar and lateral (or medial) bar of the AAFOs, from which the rest failures were extended. It is suggested that this junction must be reinforced or prevented the stress concentration to elongate the endurance of AAFO.     

Alginate–lanthanide microspheres for MRI-guided embolotherapy

In cancer therapy, a promising treatment option to accomplish a high tumor-to-normal-tissue ratio is endovascular intervention with microsized particles, such as embolotherapy. In this study, alginate microspheres (ams) were prepared with the JetCutter technique, which is based on cutting a sodium alginate solution jet stream into small droplets of uniform size which are then cross-linked with different lanthanides or iron-III, resulting in microspheres of a predefined size which can be visualized by magnetic resonance imaging (MRI). The microspheres were investigated for their size and morphology (light microscopy and scanning electron microscopy analysis), cation content and MRI properties. The lanthanide-ams formulations, with a uniform size of 250 μm and a cation content between 0.72–0.94%, showed promising results for MR imaging. This was further demonstrated for Ho³⁺-cross-linked alginate microspheres (Ho³⁺-ams), the most potent microsphere formulation with respect to MR visualization, allowing single sphere detection and detailed microsphere distribution examination. Intravascular infusion of Ho³⁺-ams by catherization of ex vivo rabbit and porcine liver tissue and assessment of the procedure with MRI clearly showed accumulation and subsequently embolization of the targeted vessels, allowing accurate monitoring of the microsphere biodistribution throughout the tissue. Therefore, the different alginate–lanthanide microsphere formulations developed in this study show great potential for utilization as image-guided embolotherapy agents.