凝胶材料制备方法及其反应动力学的研究进展

部分水凝胶材料具有良好的生物相容性、低细胞毒性和生物可降解性,广泛应用于组织工程和生物医药等领域,其中采用天然高分子明胶、壳聚糖和海藻酸钠制备复合凝胶材料,负载骨髓间充质干细胞用于修复和治疗骨缺损成为近年来的研究热点之一。因为水凝胶材料抗张强度低和化学稳定性差,所以研究凝胶反应机理和凝胶反应动力学对提高水凝胶的性能具有重要意义。本文总结了明胶、壳聚糖和海藻酸钠凝胶材料的制备方法和凝胶反应机理,比较了不同凝胶反应动力学研究方法,介绍凝胶复合材料在骨修复中的应用,为天然高分子凝胶材料的分子设计和临床应用提供思路。     

Lumbar endplate microfracture injury induces Modic-like changes,intervertebral disc degeneration and spinal cord sensitization – an in vivo rat model

BACKGROUND CONTEXTEndplate (EP) injury plays critical roles in painful IVD degeneration since Modic changes (MCs) are highly associated with pain. Models of EP microfracture that progress to painful conditions are needed to better understand pathophysiological mechanisms and screen therapeutics.PURPOSEEstablish in vivo rat lumbar EP microfracture model and assess crosstalk between IVD, vertebra and spinal cord.STUDY DESIGN/SETTINGIn vivo rat EP microfracture injury model with characterization of IVD degeneration, vertebral remodeling, spinal cord substance P (SubP), and pain-related behaviors.METHODSEP-injury was induced in 5 month-old male Sprague-Dawley rats L4–5 and L5–6 IVDs by puncturing through the cephalad vertebral body and EP into the NP of the IVDs followed by intradiscal injections of TNFα (n=7) or PBS (n=6), compared with Sham (surgery without EP-injury, n=6). The EP-injury model was assessed for IVD height, histological degeneration, pain-like behaviors (hindpaw von Frey and forepaw grip test), lumbar spine MRI and μCT, and spinal cord SubP.RESULTSSurgically-induced EP microfracture with PBS and TNFα injection induced IVD degeneration with decreased IVD height and MRI T2 signal, vertebral remodeling, and secondary damage to cartilage EP adjacent to the injury. Both EP injury groups showed MC-like changes around defects with hypointensity on T1-weighted and hyperintensity on T2-weighted MRI, suggestive of MC type 1. EP injuries caused significantly decreased paw withdrawal threshold, reduced axial grip, and increased spinal cord SubP, suggesting axial spinal discomfort and mechanical hypersensitivity and with spinal cord sensitization.CONCLUSIONSSurgically-induced EP microfracture can cause crosstalk between IVD, vertebra, and spinal cord with chronic pain-like conditions.CLINICAL SIGNIFICANCEThis rat EP microfracture model was validated to induce broad spinal degenerative changes that may be useful to improve understanding of MC-like changes and for therapeutic screening.     

Uncertainty-aware domain alignment for anatomical structure segmentation

Automatic and accurate segmentation of anatomical structures on medical images is crucial for detecting various potential diseases. However, the segmentation performance of established deep neural networks may degenerate on different modalities or devices owing to the significant difference across the domains, a problem known as domain shift. In this work, we propose an uncertainty-aware domain alignment framework to address the domain shift problem in the cross-domain Unsupervised Domain Adaptation (UDA) task. Specifically, we design an Uncertainty Estimation and Segmentation Module (UESM) to obtain the uncertainty map estimation. Then, a novel Uncertainty-aware Cross Entropy (UCE) loss is proposed to leverage the uncertainty information to boost the segmentation performance on highly uncertain regions. To further improve the performance in the UDA task, an Uncertainty-aware Self-Training (UST) strategy is developed to choose the optimal target samples by uncertainty guidance. In addition, the Uncertainty Feature Recalibration Module (UFRM) is applied to enforce the framework to minimize the cross-domain discrepancy. The proposed framework is evaluated on a private cross-device Optical Coherence Tomography (OCT) dataset and a public cross-modality cardiac dataset released by MMWHS 2017. Extensive experiments indicate that the proposed UESM is both efficient and effective for the uncertainty estimation in the UDA task, achieving state-of-the-art performance on both cross-modality and cross-device datasets.     

预防性使用盐酸西替利嗪治疗PD-1抑制剂所致斑丘疹的多中心随机对照研究

目的 探讨盐酸西替利嗪片预防性治疗PD-1抑制剂所致常见斑丘疹的临床疗效。方法 选择2020年7月—2021年12月于深圳大学第三附属医院、中国科学院大学宁波华美医院和丽水市中心医院收治的60例适合PD-1抑制剂治疗的肿瘤患者。随机分为预防用药组和治疗用药组,每组各30例。预防用药组在给予PD-1抑制剂治疗的当天同步口服盐酸西替利嗪片,每晚10mg/次,每疗程连续7d,7d内未出现斑丘疹则停止使用,如在预防用药期间出现斑丘疹,则继续口服直到斑丘疹好转停药。治疗用药组使用PD-1抑制剂治疗期间出现1级或以上级斑丘疹,则开始口服盐酸西替利嗪片,每晚10mg/次,每疗程使用的时间为出现1级或以上级斑丘疹开始口服盐酸西替利嗪片至斑丘疹级别小于1级的用药天数,观察4个疗程。比较治疗前后两组患者斑丘疹发生情况,斑丘疹发生后服用盐酸西替利嗪片天数,不同PD-1抑制剂斑丘疹发生情况。结果 治疗后,盐酸西替利嗪片预防用药组斑丘疹发生率（6.7%）显著低于治疗用药组发生率（26.7%,P＜0.05）。斑丘疹发生后,预防用药组较治疗用药组用药天数减少（P＜0.05）。使用同种PD-1抑制剂中,预防用药组斑丘疹发生率明显低于治疗用药组（P＜0.05）。结论 预防性使用盐酸西替利嗪片对PD-1抑制剂所致常见斑丘疹具有较好的预防作用,能显著降低斑丘疹发生率及斑丘疹发生后盐酸西替利嗪片的用药天数。     

基于计算机的医学影像后处理技术定位癫痫致痫灶研究进展

约30%～40%癫痫患者无法通过药物控制发作,需要手术治疗。癫痫外科术前评估的关键在于结合多模态信息的综合分析评估定位致痫灶,但目前多模态神经影像学综合分析主要依赖人工解读,主观性强,耗时费力。为提高对于常规影像学MRI阴性致痫灶定位的准确性,已有研究将医学影像后处理技术应用于分析癫痫影像,结果表明医学影像后处理技术具有能客观、精细分析大脑结构和功能异常等优点,从而有可能为致痫灶定位提供准确、有效的解决方案。本文就医学影像后处理技术在癫痫致痫灶定位中的应用进展予以综述。