DNGR-1-mediated cross-presentation of dead cell-associated antigens

Conventional dendritic cells type 1 (cDC1) are critical for inducing protective CD8⁺ T cell responses to tumour and viral antigens. In many instances, cDC1 access those antigens in the form of material internalised from dying tumour or virally-infected cells. How cDC1 extract dead cell-associated antigens and cross-present them in the form of peptides bound to MHC class I molecules to CD8⁺ T cells remains unclear. Here we review the biology of dendritic cell natural killer group receptor-1 (DNGR-1; also known as CLEC9A), a C-type lectin receptor highly expressed on cDC1 that plays a key role in this process. We highlight recent advances that support a function for DNGR-1 signalling in promoting inducible rupture of phagocytic or endocytic compartments containing dead cell debris, thereby making dead cell-associated antigens accessible to the endogenous MHC class I processing and presentation machinery of cDC1. We further review how DNGR-1 detects dead cells, as well as the functions of the receptor in anti-viral and anti-tumour immunity. Finally, we highlight how the study of DNGR-1 has opened new perspectives into cross-presentation, some of which may have applications in immunotherapy of cancer and vaccination against viral diseases.     

Clinical manifestations and outcome of nocardiosis and antimicrobial susceptibility of Nocardia species in southern Taiwan, 2011–2021

Background/PurposeNocardiosis is an uncommon infectious disease. This study aimed to assess the clinical outcome of patients with nocardiosis and examine the antimicrobial susceptibility profiles of Nocardia spp. isolated.MethodsWe retrospectively reviewed the medical records of all inpatients diagnosed with nocardiosis between 2011 and 2021. The identification of Nocardia spp. at the species level was performed with the use of MALDI-TOF and 16S rRNA assays. The antimicrobial susceptibility of Nocardia spp. was performed using the microbroth dilution method. Factors associated with 90-day all-cause mortality were identified in multivariate logistic regression analysis.ResultsOf 60 patients with nocardiosis in the 11-year study period, the lungs (55.0%) were the most common site of involvement, followed by the skin and soft tissue (45.0%). Twenty-two patients (36.7%) died within 90 days following the diagnosis. All of the Nocardia isolates were susceptible to trimethoprim-sulfamethoxazole, linezolid, and amikacin, whereas more than 70% of the isolates were not susceptible to ciprofloxacin, imipenem-cilastatin, moxifloxacin, cefepime, and clarithromycin. Nocardiosis involving the lungs (relative risk [RR], 9.99; 95% confidence interval [CI], 1.52–65.50; p = 0.02), nocardiosis involving the skin and soft tissue (RR, 0.15; 95% CI, 0.02–0.92; p = 0.04), and treatment with trimethoprim-sulfamethoxazole (RR, 0.14; 95% CI, 0.03–0.67; p = 0.01) were independently associated with 90-day all-cause mortality.ConclusionsNocardia spp. identified between 2011 and 2021 remained fully susceptible to trimethoprim-sulfamethoxazole, linezolid, and amikacin. Nocardiosis of the lungs, skin and soft tissue infection, and treatment with trimethoprim-sulfamethoxazole were independently associated with 90-day all-cause mortality.     

人工晶体开孔孔径对晶体变形及前房内流场影响的数值模拟研究

目的 研究不同人工晶体(implantable collamer lens,ICL)开孔孔径对晶体变形和前房内流场的影响。 方法 从医工结合角度出发,采用流固耦合数值模拟方法,研究人工晶体不同开孔孔径对其变形及眼内房水流场(流量、速度场、压力场、温度场)的影响。 结果 流体动力学方面,房水通过 ICL 中央孔的房水流量从大到小对应的孔径依次为 0. 36、0. 40、0. 30、0. 20、0. 10 mm,该流量与孔径呈非线性关系。 后房压力略高于前房,前后房压差随孔径增大逐渐降低。 眼内温度分布对孔径的影响并不敏感。 固体静力学方面,0. 36 mm 孔径的 ICL 变形量最小,其变形量受房水通过中央孔的流量所主导,该流量越大,ICL 的变形越小。 结论 本文综合流体动力学和固体静力学分析,验证了现有 0. 36 mm 孔径的合理性,并提出理想的孔径范围为 d≥0. 36 mm。 研究结果有助于探明 ICL 的失效机制,提高临床手术的成功率,为未来人工晶体的国产化提供经验。     

前侧入路的两种不同显露方式治疗肱骨近端骨折

目的 探讨肩关节前侧入路的两种不同显露方式治疗肱骨近端骨折的疗效差异。方法 回顾性分析2018年4月至2020年3月在孝感市第一人民医院治疗的47例肱骨近端骨折的病例资料。采用肩关节前侧入路,一种手术方式经胸大肌三角肌间隙进入26例（胸三角肌间隙组）,平均年龄（62.5±2.2）岁,根据Neer分型,二部分4例,三部分9例,四部分13例;另一种于三角肌前缘外0.5～1.0 cm,经三角肌间隙进入21例（三角肌间隙组）,平均年龄（61.3±2.2）岁,根据Neer分型,二部分4例,三部分7例,四部分10例。比较两种不同显露方式治疗的手术时间、术中出血量、骨折愈合时间、肩关节功能评分、疼痛评分及术后并发症发生情况。结果 47例患者均获随访,随访时间10～25个月,平均（15.6±4.7）个月,末次随访时骨折均一期愈合。胸三角肌间隙组与三角肌间隙组的手术时间、术中出血量、骨折愈合时间比较,差异无统计学意义（P>0.05）。末次随访Constant-Murley评分,胸三角肌间隙组为（81.2±1.5）分,三角肌间隙组为（79.4±2.1）分,两组比较差异有统计学意义（P<0.05...     

球扩式介入主动脉瓣膜支架的抗迁移力学行为

目的 研究球扩式主动脉瓣膜支架植入后的抗迁移力学行为。 方法 建立球扩式瓣膜支架介入主动脉瓣膜后的抗迁移力学模型,采用数值模拟方法研究不同瓣环椭圆率、摩擦因数、瓣膜支架材料及自体瓣叶钙化情况对瓣膜支架抗迁移力的影响规律。 结果 当主动脉瓣环椭圆率为 0. 2、0. 3、0. 4、0. 5 时,对应的最大抗迁移力分别为12. 37、10. 94、8. 50、4. 75 N;当摩擦因数为 0. 1、0. 2、0. 3 时,瓣膜支架的最大抗迁移力分别为 8. 98、11. 00、13. 10 N;L605 钴铬合金制成的瓣膜支架的锚定性要优于 316L 不锈钢制成瓣膜支架的锚定性,其对应的最大抗迁移力分别为 13. 10、9. 82 N;当自体瓣叶发生钙化时,最大抗迁移力为 13. 1 N,而未钙化时最大抗迁移力仅为 5. 51 N,相比而言降低了 57. 9% 。 结论 随着主动脉瓣瓣环椭圆率不断增大,瓣膜支架的锚定性逐渐降低;随着瓣膜支架与组织间的摩擦因数不断增大,最大抗迁移力也不断增大;L605 钴铬合金制成的瓣膜支架比 316L 不锈钢制成瓣膜支架的锚定性能优异;瓣膜发生钙化情况下瓣膜支架的锚定性要优于未发生钙化时的锚定性。 研究结果为抗迁移瓣膜支架的结构设计和临床选择提供重要的科学依据。     

桩影响前牙烤瓷冠修复后牙本质应力分布的三维有限元分析

采用三维有限元法分析桩对上颌中切牙金属烤瓷冠修复后牙本质应力分布的影响。选择一标准的上颌中切牙，经包埋、螺旋ＣＴ扫描、图形数字化，采用ＳｕｐｅｒＳＡＰ有限元分析软件在微机上建立三维有限元模型，模拟了牙槽骨、牙周膜、牙本质、桩、金属烤瓷冠的金属帽状冠及烤瓷层等结构，与临床实际结构类似。分别分析ＳＤＡ－Ⅱ型中熔合金桩修复前后，牙本质应力分布情况。结果表明：金属桩可改变牙本质原有的应力分布模式，使桩与牙本质交界区应力值增大；但与此同时又降低了牙本质应力峰值，Ｖｏｎｍｉｓｅｓ应力降低１３．９８％，最大主应力降低７．０５％。即从力学角度提示：合理桩修复可防止牙体断裂。     

一次手术法对自制两段式种植体种植效果的实验研究

本实验用自制纯钛两段式种植体,以一次手术法植入到狗的下颌前磨牙区,观察5个月,结果表明,观察期间内牙龈无炎症,种植体稳固,X线片显示种植体周围无透射区,镜下可见种植体表面与牙龈之间形成上皮附着样结构,与骨组织之间大多呈骨性愈合。提示了两段式种植体有两种设计和手术方式可供选择。骨内部分在开放的环境中也可达到骨性愈合。     

大鼠脑缺血再灌注损伤后Cx43蛋白的表达模式

目的：建立大鼠大脑中动脉闭塞（MCAO）缺血再灌注模型,探索再灌注后Cx43蛋白的表达模式。方法75只大鼠随机分为MCAO组（60只）和假手术组（15只）。MCAO组均行MCAO手术,术后根据缺血再灌注时间分为0.5、4、12、24 h 4个亚组,每组15只;假手术组不插入线栓。各组进行改良神经损伤严重程度评分（mNSS）、脑组织TTC染色及神经元尼式染色,Western blot及免疫组织化学方法检测各组脑组织Cx43蛋白的表达并进行统计学分析。结果 MCAO组造模成功率75%。MCAO组大鼠mNSS评分明显高于假手术组（P＜0.05）,脑梗死面积增加,额顶叶皮质区神经元大量损伤。Western blot结果显示：假手术组及MCAO 0.5、4、12、24 h组Cx43表达量分别为0.23±0.12、0.58±0.18、0.78±0.07、0.61±0.05和0.27±0.07, MCAO 0.5、4、12 h组与假手术组差异均有统计学意义（P＜0.05）,而MCAO 24 h组与假手术组差异无统计学意义（P＞0.05）。免疫组化结果显示：MCAO组侧脑室下区Cx43的表达在0.5 h开始升高,4 h达高峰,12 h逐渐下降,直至24 h恢复基线水平;与Western blot结果一致。结论 Cx43蛋白在脑缺血性再灌注损伤发生、发展中起重要作用。     

LED固化灯光照强度对光固化复合树脂聚合收缩的影响

目的采用数字图像相关法动态研究LED光固化灯不同光照强度对光固化复合树脂聚合收缩的影响。方法收集12颗大小接近的新鲜离体磨牙,随机分为3组,制备大小为2.0 mm×2.0 mm×2.0mm的邻(?)面洞形,洞面酸蚀冲洗后涂粘接剂光照10 s,充填3M Z350纳米复合树脂,邻面快速制造散斑,LED固化灯垂直(?)面光照40s,3组光照强度分别为300 mW/cm~2、500 mW/cm~2和800 mW/cm~2,数码相机同步实时采集光照过程中试件表面散斑的变化序列图像,用数字图像相关法计算获得各序列图上逐个像素点水平方向(x)和垂直方向(y)位移,统计线性收缩率,描绘各像素点的时域变化曲线,并用SPSS 12.01统计软件包进行方差分析和配对t检验。结果 3种光照强度下树脂x方向线收缩率分别为0.081%～0.486%、0.004%～0.316%和0.063%～0.560%,y方向线收缩率分别为0.088%～0.981%、0.003%～0.77%和0.157%～1.252%,3组之间差异有统计学意义(P<0.05);3组第20 s树脂游离面收缩x方向位移差异无统计学意义,y方向位移差异有统计学意义。结论 LED光固化灯500 mW/cm~2光照时引起的树脂聚合收缩最小。     

The Effect of Premature Loss of Deciduous Teeth a Biomktric Study in 14- and 10-Year-Olds

Abstract

Objective. To compare two methods used to examine the cement interface homogeneity of adhesively luted glass fiber posts (GFPs). Material and methods. GFPs were divided into four groups (n = 5 in each) and inserted into artificial root canals under standardized conditions: Group I = RelyX Unicem, application with application aid; Group II = RelyX Unicem; Group III = Panavia F 2.0; and Group IV = Variolink II. Posts in Groups II–IV were cemented without using an appliance. All specimens were sectioned at three levels (cervical, middle and apical) perpendicularly to the post's long axis and examined and photographed (n = 60) using scanning electron microscopy (SEM). Cement interface inhomogeneities were (A) measured by means of SEM software and (B) estimated using a graphics program with SEM images being divided into 72 equal circle segments to calculate a percentage value of inhomogeneities of the 360° circumference. Results. Median values of inhomogeneities (A/B; %) within the cement interface for the cervical, middle and apical levels of analysis, respectively were 1.4/2.1, 2.2/4.2 and 1.9/2.1 for Group I; 21.0/20.1, 24.8/23.6 and 27.0/24.3 for Group II; 1.5/1.7, 5.5/6.3 and 19.4/20.8 for Group III; and 18.1/16.7, 16.1/15.3 and 27.2/25.7 for Group IV. The two methods correlated very well (0.994), with a value of one indicating a 100% correlation. Conclusion. Both evaluation methods were found to be equally appropriate for quantifying the cement interface homogeneity of SEM cross-sections of adhesively luted GFPs.