Background & Aims: Performing ex situ normothermic machine perfusion (NMP) for ≥24 h represents an opportunity to evaluate and treat livers, but is limited by the lack of support from relevant extrahepatic organs. Incorporation of systems of renal replacement therapy, including hemodiafiltration (HDF), appears useful in this regard during prolonged ex situ liver NMP. This study aimed to demonstrate the impact and benefits associated with incorporation of continuous HDF during 24-h ex situ NMP in a relevant preclinical model, including transplantation and post-transplant follow-up. Methods: Porcine livers (n = 28) underwent 24-h ex situ NMP with either partial perfusate exchange at 12 h and no HDF (NHDF, n = 11) or HDF initiated 2 h after NMP start (n = 17). Biochemical, histological, endothelial, and metabolomic parameters were assessed. A subset of grafts undergoing NMP + HDF (n = 8) were transplanted into recipients. Results: Incorporation of HDF during NMP maintained stable pH and electrolyte levels, effectively preventing hypernatremia, hypochloremia, and hypocalcemia developing without HDF. HDF cleared metabolic wastes (e.g. urea) and inflammatory cytokines (IL-1B, IL-2, IL-6, IL-8, and IL-18), resulting in reduced injury and oxidative stress markers after 24 h (Suzuki score 0.8 ± 0.4 HDF vs. 2.7 ± 1.3 NHDF, p <0.001). Vasoprotective endothelial response mechanisms, including KLF2 and eNOS gene and protein expression, were upregulated, whereas stellate cell activation and sinusoidal contraction were reduced among HDF-treated grafts. HDF reduced metabolomic alterations arising in livers during 24-h NMP, and adequate graft maintenance using NMP + HDF was demonstrated by full functional and metabolic recovery during post-transplant follow-up. Conclusions: Continuous HDF promotes a more physiological biochemical and metabolic environment, reduces inflammation and oxidative stress, and preserves homeostatic endothelial response mechanisms in livers undergoing 24-h ex situ NMP, facilitating successful transplantation in a complex preclinical model. Impact and implications: In this preclinical study, livers were normothermically perfused for 24 h ex situ, both with and without continuous HDF. Incorporation of HDF offered relevant improvements in numerous on-device measures, including the maintenance of physiological biochemical parameters; removal of injurious metabolic wastes; and improvement of injury and stress responses in parenchymal and nonparenchymal cells. A subset of livers were successfully transplanted and demonstrated full functional and metabolic recovery during follow-up. These findings indicate that advanced renal replacement therapies, such as HDF, are a key aspect of improving and prolonging ex situ normothermic liver perfusion, although there is ongoing need to develop more physiological metabolic support protocols for livers while on such devices.

Ex situ normothermic machine perfusion (NMP) of the liver has emerged as a dynamic preservation strategy, enabling the maintenance of metabolic activity and assessment of grafts prior to transplantation. Prolonged perfusions, however, are limited by the accumulation of metabolic waste, electrolyte imbalances, and inflammatory mediators that can compromise graft function. Continuous renal replacement therapies (CRRT), especially continuous venovenous hemodiafiltration (CVVHDF), offer a potential means to support solute clearance and homeostatic regulation during extended perfusion periods. In this protocol, we describe a reproducible and safe method for integrating CVVHDF into an ex situ liver NMP system by connecting the filtration circuit independently from the main organ perfusion circuit. This configuration supports hemodynamic stability, helps prevent excessive intravascular pressures, and may reduce the risk of tissue edema. The physical connection, priming, and monitoring of the CRRT circuit are explained in detail, along with instructions on how to utilize a Hoffman clamp to simulate physiological venous pressure. When compared to direct in-line circuit integration, representative results suggest that the out-of-circuit approach is associated with reduced graft edema, while maintaining stable circuit pressure and solute clearance. This approach can be easily integrated into other similar perfusion devices in order to improve solute handling while maintaining stable perfusion dynamics.

Background The use of grafts from donation after circulatory death (DCD) overcomes the inadequate donor organ supply. Our team developed a transportable dual hypothermic oxygenated machine perfusion (DHOPE) device, which initiates DHOPE at a recipient center to reduce static cold storage (SCS) time and the risk of graft failure in DCD liver transplantation. Methods Six porcine livers per group with 30 min of warm ischemia exposure were preserved via SCS or DHOPE for 6 h and then reperfused for 12 h with whole blood to mimic transplantation. Hepatocellular and biliary function and injury were assessed in perfusate and bile samples. Molecular biomarkers and histology were compared between groups. Results Reperfusion portal vein pressure, in a flow-constant manner, and alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and gamma-glutamyltransferase (γ-GGT) release were significantly lower in the DHOPE group than in the SCS group at all time points. Higher bile production paralleled the lower levels of ALP and γ-GGT in the DHOPE group. The DHOPE group secreted more total bilirubin (TBIL) in bile, resulting in decreased TBIL in the perfusate, and livers preserved with DHOPE exhibited better cholangiocellular function. Furthermore, improvements in hypoxia, the inflammatory response, cell-free microRNAs and energy metabolism were observed in the DHOPE group. There were fewer apoptotic cells and TGF-β1-positive cells in the liver parenchyma and extrahepatic bile duct in the DHOPE group than in the SCS group. Conclusions This study demonstrates the efficacy of local 4 °C DHOPE to protect porcine liver grafts from 30-min warm ischemia damage.

Conventional static cold storage (SCS) exacerbates ischemic injury in the DCD liver, leading to severe complications for transplant recipients. To address this issue, clinical application of MP technology for donor liver preservation is underway. Simultaneously, efforts are focused on the development of various MP instruments, validated through relevant animal model experiments. Effective large animal trials play a pivotal role in clinical applications. However, challenges persist in the ex vivo preservation of DCD livers and the transplantation procedure in pigs. These hurdles encompass addressing the prolonged preservation of donor livers, conducting viability tests, alleviating ischemic injuries, and shortening the anhepatic phase. The use of a variable temperature-controlled MP device facilitates the prolonged preservation of DCD livers through sequential Dual Hypothermic Oxygenated Machine Perfusion (DHOPE) and Normothermic Machine Perfusion (NMP) modes. This protocol enhances the porcine OLTx model by improving the quality of DCD livers, optimizing the anastomosis technique, and reducing the duration of the anhepatic phase.

Introduction: For end-stage liver diseases, liver transplantation remains the most suitable therapy for its treatment. Nonetheless, the current gap between the patients on the waiting list and the graft supply, as well as the gold standard preservation method (Static Cold Storage or SCS), limits its usefulness. Extended Criteria Donors (ECD) has been proposed as a potential solution to increase the donor pool, although these have a greater susceptibility to ischemia-reperfusion injury (IRI), especially after SCS, causing delayed graft function and primary non-function. These side effects have fueled research into more suitable methods such as ex-situ normothermic machine perfusion (NMP). Methods: Sixteen healthy pig livers were subjected to normothermic perfusion using blood as a perfusion solution. in 5 experiments, taurocholic acid was administrated 6 hours after perfusion initiation. Perfusate and bile were sampled before, during and after perfusion to assess the hepatocellular injury and liver function and bile duct injury and bile production. Liver samples were collected before and after perfusion to perform analysis of general damage, stellate cell activation, oxidative stress and LSEC response. Results: AST and LDH levels increased progressively for the first 12 hours (P= 0.02 and P=0.001 respectively). Afterward, both parameters stabilized. Glucose and lactate levels decreased rapidly during the first 4 hours (p=0.003 for glucose and p=0.04 for lactate) and reached the lowest within 8 (p<0.001) and 12 hours (p<0.001) respectively. Overall, blood pH remained steady (p=0.10). Serum levels of ALKP, GGT and Bil didn’t suffer any changes during all the perfusion (p=0.99, p=0.75 and p=0.13 respectively). Bile production started within 1 hour after ex-situ perfusion. Livers supplied with taurocholic acid had a higher bile production rate, 9±3 mL/h, compared to those not supplied, 4±3 (p=0.005). No structural alterations were detected in liver samples after the Suzuki injury score assessment (p=0.33) and stellate cell activation quantification by both gene (p=0,64) and protein expression (p=0,79) and percentage of the stained area (p=0.15). Although eNOS gene and protein expression increased (p=0.01 and p=0.008 respectively), histological analysis of CD31 endothelial staining showed no differences between the baseline, 35,7±9,1 %, and the 24-hour perfusion 36,3±7,2%, of the sinusoidal area (p=0.87). This increase was associated with higher levels of MDA after the perfusion (p=0.006) as the KLF2 gene and protein expression remained invariable (p=0.80 and p=0.26 respectively). Conclusion: Our results show that NMP, as a preservation method, is capable of maintaining the normal hepatic structure and, at the same time, supporting normal metabolic activity. However, further studies should be conducted to demonstrate post-transplant liver viability.

Amelia Hessheimer, Xiran He, Mingju Liang, Javier Muñoz, Josep M. Sanahuja, Xiaoyu Tan, Marina Vendrell, Felipe León, I sabel Mora, Joaquím Albiol, Li Lin, Feng Huo, Constantino Fondevila Hospital Clínic i Provincial, Barcelona, Spain; Guanguong Shunde Innovative Design Institute, Guangdong, People’s Republic of China; General Hospital of Southern Theater Command of PLA, Guangdong, People’s Republic of China; DTI Foundation, Barcelona, Spain.

In this paper, we design a circuit components testing system for physics teaching based on embedded devices. In order to solve the problem that the computing performance of embedded devices based on NPU processor is weak and the same class samples are not detected due to high overlap, ReD_SSD Mobilenet algorithm based on SSD algorithm is proposed. Depth separable convolution is used to replace the traditional convolution of SSD algorithm to reduce the computational complexity of the model; ReDistance-IOU algorithm is used to complete the screening operation of the model pre-detection frame to reduce the system undetected rate; At the same time, the off-line 8 bit mixed quantization is adopted for the trained network model to further reduce the computational complexity of the model within the acceptable range of accuracy loss.The experimental results show that, compared with the SSD algorithm model, the ReD_SSD Mobilenet algorithm model reduces the average missing rate by 37. 4% on the physical circuit component data set. After adding the depth-separable convolution and off-line 8-bit mixed quantization, the compression rate of the model reaches 95%. The results show that the detection accuracy of ReD_SSD Mobilenet algorithm reaches 76.2%, and the detection frame rate on an embedded device is as high as 33.4 frames/s.

In the physical circuit experiment teaching of junior high school, the equipment detection link before the experiment can be completed by the target detection algorithm based on embedded devices. In order to solve the problems of slow detection speed and false detection and missed detection in the traditional target detection algorithm on embedded devices, a real-time target detection model based on YOLOv3-Tiny is proposed. By data augmentation of self-made circuit experimental equipment data set, the problem of electronic equipment category imbalance is solved. K-means clustering algorithm is used to obtain the optimal Anchor size and number of circuit experimental equipment data sets, and the parameters of YOLOv3-Tiny algorithm are improved. The test results show that the improved YOLOv3-Tiny algorithm can achieve a detection accuracy of 94.61% and a detection frame rate of 39 frame/s on the NPU processor of the embedded device RK3399Pro development board.

为了实现基于边缘计算的电路实验器材检测算法,该文研究基于YOLOv3-Tiny算法的重叠池化(Overlapping Pooling,OP)_YOLOv3 Tiny算法.采用5层最大池化(MAX Pooling)层对特征矩阵进行重叠池化降维操作,削弱池化的特征弱化现象;优化调整图像尺寸,丰富小目标的浅、深层信息;同时,采用K-means聚类算法获得锚框(Anchor box)的最佳参数.实验结果表明,基于OP_YOLOv3 Tiny算法在RK3399Pro开发板上对电路实验器材的检测帧率达到33.8 f/s,检测精准率达到88.1％,与YOLOv3-Tiny算法相比,精测精准率提升了4.7％,可以满足实时目标检测的要求.

目的:初步探索离体肝脏双泵双氧合机械灌注设备在离体猪肝脏低温灌注中的可操作性以及稳定性.方法:从45～50 kg雌性巴马小型猪获取供肝,利用灌注设备同时对肝动脉和门静脉实施低温携氧灌注8 h.肝动脉采用压力恒定模式控制,门静脉采用流量恒定模式控制,观察灌注过程中的流量、压力、血气指标、炎症因子以及病理组织学评分的变化.采用IBM SPSS Statistics 23.0统计学软件进行实验数据分析.结果:灌注过程中,肝动脉压力稳定维持在24.09～24.65 mmHg(1 mmHg=133.32 Pa),流量从初期的0.04 mL/[min·g(肝重)]逐渐升高至0.09 mL/[min·g(肝重)];门静脉的流量稳定维持在0.47～0.50 mL/[min·g(肝重)],压力呈降低趋势,从初期的2.79 mmHg下降至1.84 mmHg.灌注液pH值、葡萄糖(Glu)以及乳酸(Lac)水平维持稳定.肝组织的炎症因子白介素6(IL-6)和肿瘤坏死因子α(TNF-α)亦维持稳定.在组织病理学评价方面,肝组织的空泡化水平呈下降趋势,而肝组织的坏死、水肿以及肝窦扩张水平则维持稳定.结论:该离体肝脏双泵双氧合机械灌注设备能够无故障地运转8 h,同时维持肝脏的低代谢状态,降低肝内灌注阻力和改善肝细胞缺氧,具有安全性和稳定性.

There is a dearth of effective parameters for selecting potentially transplantable liver grafts from expanded-criteria donors. In this study, we used a nuclear magnetic resonance (NMR) relaxation analyzer-based assay to assess the viability of ex vivo livers obtained via porcine donation after circulatory death (DCD). Ex situ normothermic machine perfusion (NMP) was utilized as a platform for viability test of porcine DCD donor livers. A liver-targeted contrast agent, gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA), was injected into the perfusate during NMP, and the dynamic biliary excretion of the Gd-EOB-DTPA was monitored by measuring the longitudinal relaxation time (T1). The longitudinal relaxation rate (R1) of the bile was served as a parameter. The delay of increase in biliary R1 during early stage of NMP indicated the impaired function of liver grafts in both warm and cold ischemia injury, which was correlated with the change of alanine aminotransferase. The preservative superiority in cold ischemia of dual hypothermic oxygenated machine perfusion could also be verified by assessing biliary R1 and other biochemical parameters. This study allows for the dynamic assessment of the viability of porcine DCD donor livers by combined usage of ex situ NMP and NMR relaxation time based assay, which lays a foundation for further clinical application.

目的 构建离体肝脏常温机械灌注设备,探讨灌注实验过程对红细胞的影响.方法 获取健康雌性巴马小型猪肝脏和血液,利用常温机械灌注设备对离体肝脏持续灌注8 h,温度设定37℃,动脉压力设定80/60 mmHg,门静脉设定恒流模式(0.5 mL/minrg),记录灌注过程中灌注液温度、肝动脉和门静脉流量等数据,每小时化验红细胞及其他相关指标,包括红细胞压积(Hematocrit,HCT)、血红蛋白(Hemoglobin,HGB)、总胆红素(Total Bilirubin,TBIL)、间接胆红素(Indirect Bilirubin,IBIL)、溶血率、乳酸(Lactate,Lac)以及血糖(Glucose,Glu).结果 灌注过程中灌注液温度稳定维持37℃,肝动脉流量从最初的(54.64±11.94)mL/min,上升到(249.34±93.01)mL/min,门静脉流量平均值稳定在(442.67±79.19)mL/min.灌注开始和结束时HCT和HGB分别为(27.67±2.42)％、(9.40±0.81)g/dL和(28.00±2.45)％、(9.52±0.81)g/dL.分别比较灌注开始和结束时HCT、HGB数值,均无统计学差异.灌注前后TBIL和IBIL水平比较,差异无统计意义.灌注过程中每小时检测溶血率均为0.Lac从灌注开始的(2.52±0.39)mmol/L下降至灌注结束的(0.35±0.07)mmol/L(P＜0.05).Glu在第2小时达到最高值(21.37±5.96)mmol/L,灌注结束时下降至(9.78±2.63)mmol/L(P＜0.05).结论 离体肝脏常温机械灌注设备能够维持HCT和HGB稳定,不会导致溶血;过程中Lac和Glu持续消耗,间接反映了灌注过程红细胞携氧能力可以改善离体肝脏功能.

目的 探讨自主研发的常温机械灌注(Normothermic Machine Perfusion,NMP)设备对不同热缺血时间下供肝的保护作用.方法 选取雌性巴马猪作为血液和肝脏供体,分为DCD30min组和DCD60min组,利用NMP设备灌注12 h,观察灌注过程中两组的灌注参数、血气生化指标以及胆汁相关指标的水平.结果 两组供肝不同时间点的肝动脉流量比较,差异无统计学意义(P＞0.05);DCD 30 min组的门静脉压力低于DCD 60 min组,差异有统计学意义(P＜0.05);两组的酸碱平衡、乳酸、血糖、ALP、γGGT和TBIL的水平比较,均无统计学意义(P＞0.05);DCD 60 min组的尿素氮水平更高,DCD 30 min组的转氨酶水平更低,均具有统计学差异(P＜0.05);两组肝脏均能持续合成胆汁,胆汁的pH、碳酸氢根及葡萄糖水平均无统计学差异(P＞0.05);而胆汁胆红素和胆汁酸浓度具有统计学差异(P＜0.05).结论 NMP12h,两组不同热缺血时间的供肝都能进行有氧代谢和持续合成胆汁,提示自主研发的NMP设备可有效保护有热缺血损伤的供肝.

目的 利用离体肝脏常温灌注系统初步探索门静脉恒压控制模式与门静脉恒流控制模式对热缺血损伤肝脏的保存效果差异.方法 使用雌性巴马小型猪获取血液和供肝,所有供肝的热缺血时间为60 min,一组采用门静脉恒压控制模式(n=6),一组采用门静脉恒流控制模式(n=6),利用常温机械灌注设备灌注6 h,观察肝脏的灌注参数、血气生化指标以及组织病理学变化.结果 灌注前,两组的冷缺血时间差异无统计学意义(P>0.05).猪肝脏经过6 h的常温机械灌注,恒压组的肝动脉流量为(0.13±0.08)mL/min/g(肝重)比恒流组的(0.25±0.09)mL/min/g(肝重)更低(P<0.05).两组比较,灌注液的pH、乳酸水平、葡萄糖水平差异无统计学意义(P>0.05);尿素氮水平除了在第2小时,两组比较差异无统计学意义(P>0.05).对于肝细胞酶学和总胆红素水平,两组在灌注结束时亦差异无统计学意义(P>0.05).恒流组的胆汁生成量为(54.47±15.63)mL,较恒压组的(6.98±3.20)mL更多(P<0.05).两组在病理学评分的比较差异无统计学意义(P>0.05).结论 门静脉恒流模式更有利于肝动脉的供血,从而促进肝细胞进行胆汁合成,提示门静脉流量控制模式可能是更合适的灌注方式.但是这仍需要通过动物肝移植实验以及临床肝移植的数据进一步验证.

离体肝脏灌注技术在不同的器官保存、评估、修复阶段,有不同的模式切入,现阶段的商品化技术集中在低温机械灌注(hypothermic machine perfusion,HMP)、亚低温机械灌注(sub-normothermic machine perfusion,SNMP)、常温机械灌注(normothermic machine perfusion,NMP)的模式上.本文针对4款商用设备进行技术剖析,发现市场上暂无满足所有灌注模式及不同模式组合的设备.同时本文结合器官灌注模式各阶段的特点及肝脏临床生理特点,研发一个满足所有离体肝脏灌注临床研究及应用的全功能产品.

在分析了驾驶员疲劳检测系统的算法以及其实现的复杂度之后,提出基于TI公司的DM642数字处理器的驾驶员疲劳检测系统的设计与实现方法,结合DM642性能特性的优化手段.其中文章介绍驾驶员疲劳检测系统实现,详细介绍利用各种优化手段对人脸检测部分进行处理,并对优化前后的性能进行对比.实验结果表明,该人脸检测系统在640*480的动态视频检测中达到20 fps的实时化处理速度.

In order to improve the accuracy of the eye gaze tracking technology, this paper presents a novel pupil detection algorithm based on Hough Transform with edge gradient direction information. According to the pupil pixel features in the context of infrared corneal reflection, taking advantage of two-dimensional Hough Transform, combining the edge gradient direction and a fixed range of discrete pupil radius, this algorithm counts parameter space discrete transform points to locate pupil center. It effectively filters out noise, reduces the discrete transform point statistics and calculates pupil's parameters. Experimental results show that the algorithm has a higher accuracy and real-time than the previous models.