Quantitative analysis of collagen morphology in breast cancer from millimeter scale using multiphoton microscopy

The tumor microenvironment(TME)is now recognized as an important participant of tumor progression.As the most abundant extracellular matrix component in TME,collagen plays an important role in tumor development.The imaging study of collagen morphological feature in TME is of great significance for understanding the state of tumor.Multiphoton microscopy(MPM),based on second harmonic generation(SHG)and two-photon excitation fluorescence(TPEF),can be used to monitor the morphological changes of biological tissues without labeling.In this study,we used MPM for large-scale imaging of early invasive breast cancer from the tumor center to normal tissues far from the tumor.We found that there were signi¯cant di®erences in collagen morphology between breast cancer tumor boundary,near tumor transition region and normal tissues far from the tumor.Furthermore,the morphological feature of eight collagen¯bers was extracted to quantify the variation trend of collagen in three regions.These results may provide a new perspective for the optimal negative margin width of breast-conserving surgery and the understanding of tumor metastasis.

MORPHOLOGY AND MECHANICAL PROPERTIES OF POLYPROPYLENE WITH in situ FORMED POLYAMIDE-6 FIBRILS

in situ Fibril formation of polyamide-6 （PA6） in isotropic polypropylene （iPP） was first fabricated using a slit die extrusion and hot stretching process. Then the prepared materials were subjected to injection molding in the temperature range higher than the melting temperature of iPP but lower than that of PA6. The obtained injection-molded samples were characterized via scanning electron microscopy （SEM）, differential scanning calorimetry （DSC） and two-dimensional wide- angle X-ray scattering （2D-WAXS）. Mechanical properties were also investigated. The SEM result shows that the optimum fibril formation could be only achieved in the range of 20 wt% to 30 wt% of PA6 content for the studied system. The fibril morphology changes along the sample thickness in the injection-molded bars. The fibril morphology in the skin layer was better than that in the core layer. 2D-WAXS results showed that the orientation of PP decreased with the increase of PA6 content, which indicated that the orientation of PP was confined by PA6 fibrils. Combined consideration of mechanical properties and morphology indicates that only PP/PA6 composites with 20 wt% of PA6 content show better properties because of the better fibril morphology and PP chain orientation.

Role of corneal collagen fibrils in corneal disorders and related pathological conditions

The cornea is a soft tissue located at the front of the eye with the principal function of transmitting and refracting light rays to precisely sense visual information. Corneal shape, refraction, and stromal stiffness are to a large part determined by corneal fibrils, the arrangements of which define the corneal cells and their functional behaviour. However, the modality and alignment of native corneal collagen lamellae are altered in various corneal pathological states such as infection, injury, keratoconus, corneal scar formation, and keratoprosthesis. Furthermore, corneal recuperation after corneal pathological change is dependent on the balance of corneal collagen degradation and contraction. A thorough understanding of the characteristics of corneal collagen is thus necessary to develop viable therapies using the outcome of strategies using engineered corneas. In this review, we discuss the composition and distribution of corneal collagens as well as their degradation and contraction, and address the current status of corneal tissue engineering and the progress of corneal cross-linking.

Effects of fibril- or fixed-collagen on matrix metalloproteinase-1 and tissue inhibitor of matrix metalloproteinase-1 production in the human hepatocyte cell line HLE

AIM: Matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) are central to the spontaneous resolution of liver fibrosis. The mechanisms involved have been investigated in hepatic steilate cells (ISC), but not in hepatocytes. We investigated the effects of fibril- and fixed-collagen on MMP-1 and TIMP-1 production in hepatocytes, using the HLE cell line.METHODS: Fibril type T and Ⅳ collagen were prepared by HCl digestion of type T and Ⅳ collagen, respectively.For fixed-collagen, culture dishes were coated with fibril type Ⅰ or Ⅳ collagen and fixed by ultraviolet. Type Ⅰcollagenase activity was measured using fluorescein isothiocyanate-labeled type Ⅰ collagen. MMP-1 and TIMP-1 in HLE cells were measured by a one-step sandwich enzyme immunoassay.RESULTS: Both fibril type Ⅰand Ⅳ collagen significantly increased type Ⅰ coilagenase activity about two-fold compared with no fibril collagen. The effects of the fibril collagen were not affected by the coating condition. There was no significant difference in the effects on collagenase activity between cells cultured in medium containing fibril type Ⅰ collagen and those cultured in the presence of type Ⅳ collagen. Both types of fibril collagen significantly increased MMP-1 production, and showed more than 10-fold higher levels of MMP-1 than the control. The enhanced MMP-1 production by fibril collagens was unaffected by the coating condition. By contrast, TIMP-1 production was not changed by the addition of fibril type Ⅰ or Ⅳ collagen,and neither was it affected by the coating conditions.Coating with type Ⅰ collagen significantly suppressed MMP-1production by almost one-tenth compared with no coating.By contrast, lIMP-1 production was not affected by either the absence of a collagen coat or by increasing the concentration of the coating collagen.CONCLUSION: These results indicated that, in HLE cells,fibril- and fixed-collagen have opposite effects on MMP-1production without affecting TIMP production. Fibril collagen induced collagenase activity by up-regulation of MMP-1 production without affecting TIMP-1 production.By contrast, fixed collagen reduced MMP-1 production.Our results suggest that hepatocytes might also play an important role in the regulation of the hepatic fibrosis alongside HSC.

Studies on morphology and biomechanics of the coronary arteries

Morphology and biomechanics of the coronary arteries have been studied in the human and common experimental animals since 1979. The types of the coronary distribution, the artery-vein relationship,and the intramural vascular changes and the coronary colla

Different architectures of collagen fibrils enforce different fibrillogenesis mechanisms

According to current knowledge on collagen fibril-logenesis, collagen fibrils are formed by a cooperative process involving lateral fusion of small protofibrils. Almost all the experimental research, however, was carried out on tendon collagen, whose fibrils are characterized by approximately straight subfibrils. By contrast, in most tissues the collagen fibril sub-units follow a helical course in which geometrical constraints prevent lateral fusions, thereby implying a different mechanism where collagen fibrils grow by addition of individual microfibrils rather than by lateral fusion of pre-assembled subfibrils. The proc-ess at the origin of these fibrils may provide a simple, automatic explanation for the remarkable uniformity in fibrils size observed in most tissues without re-quiring the intervention of unknown mechanisms of diameter control. Other mechanisms of growth con-trol remain indispensable to terminate the fibril-logenesis process in tendons and ligaments.

<i>In Situ</i>Hydroxyapatite Synthesis: Influence of Collagen on Its Structural and Morphological Characteristic

Hydroxyapatite (HA) was synthesized in situ by the precipitation method, with and without the presence of collagen (COLL), to study its influence on HA’s structural and morphological characteristics. The material was characterized by energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR), wide-angle X-ray diffraction (WAXD), thermogravimetric analysis (TG) and scanning electron microscopy (SEM). The Ca/P molar ratio was influenced by collagen addition—1.89 and 2.38 for samples without and with collagen, respectively. The WAXD pattern revealed better resolution and intensity besides higher crystallinity degree of the HA in the presence of collagen. The photomicrographs showed a strong influence of collagen on the HA morphology.

心电图MVP积分在阵发性心房颤动射频导管消融术后随访中的临床价值

目的探讨心电图P波形态、电压及时间(MVP)积分在阵发性心房颤动(下称房颤)射频导管消融术(下称消融)后随访中的临床价值。方法选择2018年2月至2022年1月嘉兴市第一医院(嘉兴大学附属医院)收治的心房颤动消融患者84例,随访1年,依据房颤是否复发分为未复发组60例、复发组24例。比较两组患者消融前、消融后1年心电图P波参数(MVP)积分、超声心动图检查指标。结果未复发组消融前患者P波时间、MVP积分小于复发组,P波面积大于复发组,未复发组消融后1年患者P波时间、V_(1)P波负向部分振幅和时间的乘积(PtfV_(1))、P波面积、MVP积分小于复发组,差异均有统计学意义(均P<0.05)。复发组消融后1年PtfV_(1)大于消融前,差异有统计学意义(P<0.05)。心电图P波时间、P波面积、MVP积分是房颤消融后房颤复发的影响因素(均P<0.05)。ROC曲线分析发现,MVP积分诊断房颤复发的AUC较大(P=0.001)。未复发组消融前后左心房前后径(LAD)小于复发组,消融后左心室短轴缩短率、左心室射血分数大于复发组,差异均有统计学意义(均P<0.05)。复发组消融前后MVP积分与LAD均呈正相关(r=0.312、0.381,均P<0.05)。结论心电图MVP积分有助于预测房颤消融后复发。

Relationship between Atrial Tissue Remodeling and ECG Features in Atrial Fibrillation

The difference in the atrial organizational structure between patients with atrial fibrillation (AF) and those with sinus rhythm was investigated.In order to analyze the rationality in explaining the electrocardiogram (ECG) characteristics of AF with statistics data or tissue remodeling model,and the logical relationship between the hypothesis of pulmonary veins (PV) muscle sleeves and that of multi wavelets in mechanism of AF,we examined the expression of collagen volume fraction of type I (CVF-I ) with picrosirius red staining,connexin 40 (Cx40) by immunohistochemistry,and intercalated disc (ID) using transmission electron microscope in atrial tissue.The results showed that there was significant difference in the expression of CVF-I (t=3.827,P<0.01),Cx40 (t=4.21,P<0.01),and groups of the ID that keeping the electrical transmission and atrial electrical coupling synchronization (t=15.116,P<0.001),but no significant difference was found in total IDs (t=0.611,P=0.543) between patients with AF and those with sinus rhythm.The quantitative differences in the tissue remodeling could not explain the ECG characteristics of AF.The number of normal IDs and abnormal distribution are the structural basis to trigger and maintain atrial electrical remodeling,and induce and maintain AF.Such histological reconstruction supports the hypothesis of multi wavelets and can also explain ECG features.

Platelet-Derived Growth Factor-A Overexpression Correlates with Atrial Fibrosis in the Patients with Atrial Fibrillation Secondary to Rheumatic Valvular Disease

Objective: To investigate the relationship between platelet-derived growth factor-A (PDGF-A) and atrial fibrosis in patients who have developed atrial fibrillation (AF) secondary to rheumatic valvular disease. Methods: 84 selected patients participated in the current study who have developed rheumatic heart disease and were going to have a cardiac surgical operation. In the current study, whole subjects were divided into two group, they were atrial fibrillation (AF) group (the quantity is thirty-nine) and sinus rhythm (SR) group (the quantity is forty-five). Before the operation, complete clinical data was available for the whole patients. During the operation, the right atrial tissue (0.3 - 0.5 mm3) was disserted from every patient. Right atrial fibrosis was observed by Masson staining and the distribution of PDGF-A in right atrium specimen was observed by immunohistochemistry. RT-PCR techniques were applied to admeasure the mRNA expressions of PDGF-A in patients’ atrial tissue. At the same time, western-Blot techniques were employed to admeasure the protein expressions of PDGF-A. Results: In baseline clinical characteristics, in both AF group and SR group, there was no apparently difference between them (P > 0.05);compared with SR group, the diameters of left atrium and right atrium in AF group were apparently increased (P Conclusion: Atrial remodeling plays an important role in patients with valvular atrial fibrillation;PDGF-A in patients with AF was highly expressed in the right atrial, and was closely related with atrial fibrosis.

风湿性二尖瓣狭窄及持续性房颤对左心耳形态学及功能学超声指标的影响

目的 探讨风湿性二尖瓣狭窄(RMS)及持续性房颤(PeAF)对左心耳形态学和功能学超声指标的影响。方法 回顾性分析57例RMS合并PeAF(RMS-PeAF)患者(RMS-PeAF组)、22例单纯RMS患者(RMS组)、31例单纯PeAF患者(PeAF组)及40例正常健康者(正常对照组)的临床资料。比较4组的左心耳形态学超声指标[左心耳最大切面面积指数(LAAAImax)、左心耳最小切面面积指数(LAAAImin)、左心耳最大体积指数(LAAVImax)、左心耳最小体积指数(LAAVImin)、左心耳入口最大径线指数(LAAODImax)、左心耳长度指数(LAALI)]和左心耳功能学超声指标[左心耳血流充盈峰值速度(LAA-PFV)、左心耳血流排空峰值速度(LAA-PEV)、左心耳前壁收缩运动速度(LAA-AWSV)、左心耳前壁舒张运动速度(LAA-AWDV)、LAA-PFV/LAA-AWDV值、左心耳面积缩小率(LAAAR)、左心耳射血分数(LAAEF)],以及左心耳自发声学显影(SEC)分级。结果 (1)RMS-PeAF组的LAAAImax、LAAAImin、LAALI、LAAODImax大于PeAF组、正常对照组,LAAVImax、LAAVImin大于其余3组(P<0.05);RMS组及PeAF组的LAAAImin、LAAVImin、LAALI、LAAODImax大于正常对照组,且RMS组的LAAODImax大于PeAF组(P<0.05)。(2)RMS-PeAF组的LAA-PFV、LAAAR、LAAEF小于其余3组,LAA-PEV小于正常对照组,LAA-AWSV、LAA-AWDV小于PeAF组和正常对照组,LAA-PFV/LAA-AWDV值大于PeAF组(P<0.05);RMS组的LAA-PFV、LAA-PEV、LAAAR、LAAEF小于正常对照组,LAA-AWSV、LAA-AWDV小于PeAF组和正常对照组,而LAA-PFV/LAA-AWDV值大于PeAF组和正常对照组(P<0.05);PeAF组的LAA-PFV、LAA-PEV、LAAAR、LAAEF、LAA-PFV/LAA-AWDV值小于正常对照组(P<0.05)。(3)4组的左心耳SEC分级差异有统计学意义,其中RMS-PeAF组的左心耳SEC分级高于其余3组(P<0.05)。结论 单纯RMS和单纯PeAF对左心耳形态学及部分功能学超声指标的影响程度相似,且二者同时存在会产生叠加效应,但RMS对心耳前壁运动的抑制作用更为显著。

实时三维经食管超声心动图定量评估心房颤动患者左心耳形态及功能改变的临床意义

目的探究实时三维经食管超声心动图(RT-3D-TEE)定量评估心房颤动(AF)患者左心耳(LAA)形态及功能改变的临床意义。方法选取2018年10月至2020年9月于本院检查的60例AF患者作为研究组,另选取同期于本院检查的无AF的60例其他心脏疾病患者作为对照组。所有患者均行RT-3D-TEE定量评估,比较两组LAA形态[LAA最大开口直径(D_(max))、最小直径(D_(min))、直径变化率(D%),LAA开口最大面积(A_(max))、最小面积(A_(min))、面积变化率(A%)]及功能参数变化[LAA舒张末期容积(LAA-EDV)、收缩末期容积(LAA-ESV)、LAA射血分数(LAA-EF)]。结果研究组D_(max)、D_(min)、A_(max)、A_(min)均高于对照组,A%、D%均低于对照组,差异有统计学意义(P<0.05)。研究组LAA-EDV、LAA-ESV均高于对照组,LAA-EF低于对照组,差异有统计学意义(P<0.05)。结论采用RT-3D-TEE定量评估AF患者能获得准确LAA形态及功能状态,为临床诊断提供可靠的依据,值得推广应用。

非瓣膜性心房颤动患者左心耳解剖形态及相关参数与卒中的关系

目的探究非瓣膜性心房颤动患者左心耳解剖形态及相关参数与卒中的关系。资料与方法回顾性分析2015年3月—2020年1月就诊于解放军总医院,接受心脏CT血管造影和经食管超声检查的721例非瓣膜性心房颤动患者。收集患者的临床资料、心脏CT血管造影、经胸超声及经食管超声结果。根据既往有无卒中史分为卒中组105例和非卒中组616例,获取左心耳的解剖形态及相关参数,采用多因素Logistic回归分析左心耳解剖形态及相关参数与卒中的关系。结果卒中组与非卒中组患者CHA2DS2-VASc评分(t=-13.65,P<0.001)、心房颤动类型(χ^(2)=5.85,P=0.016)、左心耳开口平面与长径夹角(χ^(2)=5.483,P=0.009)等差异有统计学意义。多因素Logistic回归分析显示,左心耳开口平面与长径夹角(OR=2.813,95%CI 1.526~5.184,P=0.001)、CHA2DS2-VASc评分(OR=3.497,95%CI 2.801~4.336,P<0.001)是卒中的独立危险因素。结论左心耳开口平面与长径夹角是预测卒中的独立危险因素,左心耳形态传统的四分类型不是卒中风险的独立危险因素。

羧基化的聚酰胺—胺/无定形磷酸钙诱导Ⅰ型胶原纤维矿化的研究

目的:利用羧基化的聚酰胺—胺稳定矿化物前驱相无定形磷酸钙,合成并表征同时具有有机和无机材料特性的仿生矿化复合物(ACP/CPAMAM),并观察其诱导胶原纤维仿生矿化的效果。方法:制备ACP/CPAMAM纳米复合物,并通过透射电子显微镜、选区电子衍射、粒径分析、电位分析等对其表征和验证。最终体外实验应用牛跟腱胶原纤维,借助透射电镜—能谱分析观察胶原纤维内部及周围晶体形成情况。结果:ACP/CPAMAM纳米复合物成功合成并且为无定形相,平均粒径为25.13 nm。透射电子显微镜及选区电子衍射显示,ACP的表面出现10 nm厚的低衬度包裹层,证实了ACP/CPAMAM的成功合成且其结构为非晶相。透射电镜—能谱分析显示,应用ACP/CPAMAM矿化肌腱Ⅰ型胶原纤维后可见高密度晶体,胶原纤维周围可见致密、连续的晶体形成,证实该纳米复合物可连续诱导胶原纤维矿化。结论:ACP/CPAMAM作为一种新型的纳米复合生物材料具有良好的生物活性和仿生矿化特性,能够诱导胶原纤维形成矿化产物,提示ACP/CPAMAM可能成为一种新型诱导胶原纤维仿生再矿化的纳米材料。

左心耳造影剂滞留与非瓣膜性心房颤动相关脑卒中风险的关联

目的:探索左心耳造影剂滞留与非瓣膜性心房颤动(房颤)相关脑卒中风险的关联。方法:选取2019年1月至2022年6月于新疆医科大学第一附属医院行左心耳封堵术的非瓣膜性房颤患者204例,按照术后有无左心耳造影剂滞留,造影剂滞留患者和无造影剂滞留患者分别有76例(37.3%)和128例(62.7%),脑卒中患者和非脑卒中患者分别有87例(42.6%)和117例(57.4%),这两类患者中造影剂滞留患者分别有64例(73.6%)和12例(10.3%)。规范采集经胸超声心动图、经食道超声心动图、经皮左心耳封堵术中左心耳造影图像,收集患者基线资料,通过倾向性评分匹配调整混杂因素,分析匹配后左心耳造影剂滞留与房颤相关脑卒中风险的关联。结果:共100例患者按1:1的比例匹配成功,其中造影剂滞留患者和无造影剂滞留患者各50例,脑卒中患者和非脑卒中患者分别有55例和45例;其平均年龄为(70.5±10.5)岁,男性占56.0%。匹配后的多因素Logistic回归分析显示,左心耳造影剂滞留(OR=66.125,95%CI:6.880~635.551,P<0.001)、CHA2DS2-VASc评分(OR=3.263,95%CI:1.621~6.568,P=0.001)、左心耳深度之和(OR=1.128,95%CI:1.042~1.120,P=0.003)、左心耳开口直径之和(OR=0.773,95%CI:0.665~0.898,P=0.001)均与房颤相关脑卒中风险有关。结论:在非瓣膜性房颤患者中,左心耳造影剂滞留与房颤相关脑卒中风险有关,造影剂滞留患者的左心耳深度之和较大,左心耳开口直径之和较小。

P波参数与形态对心房颤动及其他心血管疾病的预测作用

心房颤动是最常见的心律失常,其特点是快速和异常的心房激活导致心房功能受损。因P波特征的任何偏转都意味着心房激活时间和传导途径的变化,因此,了解P波典型形态学改变以及异常P波参数与心房颤动间的联系可做到早期心房颤动的精准预测。现重点介绍P波形态、P波参数与心房颤动的联系,探索基于人工智能技术下P波对心房颤动的预测价值,以及P波参数对其他心血管疾病的预测作用,为将来P波对心房颤动和其他心血管疾病发生的早期识别提供一种新的手段。

Left atrial appendage morphology in patients with atrial fibrillation in China： implications for stroke risk assessment from a single center study

Background The left atrial appendage （LAA） is thought to be the main source of thrombi in patients with atrial fibrillation （AF）. The purpose of this study was to describe the LAA orifice diameter, LAA length, and morphologic type of the LAA in Chinese patients with AF as well as to evaluate whether these LAA parameters are associated with a history of stroke in patients with AF from a single center in China. Methods The study population consisted of 219 consecutive patients with drug-refractory, symptomatic paroxysmal, or persistent AF scheduled to undergo radiofrequency catheter ablation in our single center. All patients underwent extensive clinical assessment and multidetector computed tomography to fully explore the anatomy of the LAA. Results Of the 219 patients who underwent catheter ablation procedures, chicken wing LAA morphology was found in 114 patients （52.2%）, windsock in 52 （23.9%）, cauliflower in 29 （13.0%）, and cactus in 24 （10.9%）. Compared with the windsock LAA morphology, cactus had a larger left atrial diameter （（42.40±3.68） and （37.91±4.32） mm, P=-0.005） and LAA orifice diameter （（27.38±3.70） and （24.14±3.58） mm, P=0.048）. The LAA length was significantly larger in the chicken wing morphology than in the windsock （（37.50±6.74） and （31.33±3.92） ram, P=0.015） and cauliflower morphologies （（37.50±6.74） and （31.33±3.92） mm, P=-0.015）. According to their medical records, 26 patients （11.9%） had suffered a prior stroke. Compared with patients who had no history of stroke, the prior-stroke patients were older （62.04±8.07 and 58.24±9,24, P=-0.047） and there were fewer patients with chicken wing （23.1% and 59.1%, P=-0.001） and more patients with cauliflower （26.9% and 9.8%, P=-0.046）. Multivariate Logistic regression analysis demonstrated that age （odds ratio （OR） 1.26; 95% confidence interval （CI） 1.08-1.47; P=0.003）, non-chicken wing morphology （OR 5.82; 95% CI 1.61- 21.03; P=-0.007）, and LAA orifice diameter （OR 1.25; 95% CI 1.05-1.49; P=0.014） were independent predictors of stroke after adjusting for all parameters that emerged as potential confounders with univariate analysis. Conclusion LAA analysis can potentially be used to inform guidance on the implication for stroke risk assessment.

Optimal bulk-heterojunction morphology enabled by fibril network strategy for high-performance organic solar cells

A bicontinuous network formed spontaneously upon film preparation is highly desirable for bulk-heterojunction(BHJ) organic solar cells(OSCs). Many donor-acceptor(D-A) type conjugated polymers can self-assemble into polymer fibrils in the solid state and such fibril-assembly can construct the morphological framework by forming a network structure, inducing the formation of ideal BHJ morphology. Our recent works have revealed that the fibril network strategy(FNS) can control the blend morphology in fullerene, non-fullerene and ternary OSCs. It has been shown that the formation of fibril network can optimize phase separation scale and ensure efficient exciton dissociation and charge carriers transport, thus leading to impressive power conversion efficiencies(PCEs) and high fill factor(FF) values. We believe that FNS will provide a promising approach for the optimization of active layer morphology and the improvement of photovoltaic performance, and further promote the commercialization of OSCs.

碳化二亚胺联合N-羟基琥珀酰亚胺交联过氧乙酸-乙醇处理后的肌腱:体外形态学特征

背景:过氧乙酸已被证明能有效灭活异体肌腱中的潜在微生物,但会使胶原分子内、分子间交联受到破坏,因此如何减弱或者修复这种损伤,灭菌的同时改善肌腱形态学特性是一个待解决的问题。目的:探讨碳化二亚胺/N-羟基琥珀酰亚胺交联是否对过氧乙酸-乙醇处理后的肌腱起保护作用。方法:选取18只新西兰大白兔,切取半腱肌肌腱(36条)作为实验材料。将肌腱分3组处理,每组12条:对照组肌腱脱细胞后置入过氧乙酸-乙醇溶液中进行灭菌处理;实验1组在对照组处理的基础上,置入MES缓冲液中浸泡24 h,置入含50 mmol/L MES、2.5 mmol/L碳化二亚胺、5 mmol/L N-羟基琥珀酰亚胺的乙醇交联液中浸泡6 h;实验2组在对照组处理的基础上,置入MES缓冲液中浸泡24 h,置入含50 mmol/L MES、5 mmol/L碳化二亚胺、5 mmol/L N-羟基琥珀酰亚胺的乙醇交联液中浸泡6 h;3组处理后均进行伽马辐照灭菌,分别进行光学显微镜、扫描电镜、透射电镜与偏光显微镜观察。结果与结论:①光学显微镜、扫描电镜:空白组胶原纤维无序性较强,肌腱细胞散在分布,腱束间连接松散纤维间隙较宽,纤维缠绕在一起,波形紊乱;两实验组肌腱平行排列且均匀规则,呈波浪形,纤维间隙小,以实验2组表现更为显著;②透射电镜:实验2组胶原原纤维直径、胶原原纤维指数大于对照组、实验1组(P<0.05),实验1组、实验2组胶原纤维质量平均直径大于对照组(P<0.05),对照组胶原纤维密度大于实验1组、实验2组(P<0.05);③偏光显微镜:3组均为Ⅰ型胶原纤维占比较大、Ⅲ型胶原纤维占比较小,对照组纤维密度较小,间隙较宽松;实验1组纤维密度有所增加,实验2组纤维间隙最小、密度最为大,对照组胶原卷曲周期大于实验1组、实验2组(P<0.05);④结果表明,碳化二亚胺联合N-羟基琥珀酰亚胺交联处理能在微观角度改善肌腱的受损程度,对过氧乙酸-乙醇处理后肌腱起保护作用,且碳化二亚胺浓度为5 mmol/L较2.5 mmol/L处理可获得更好的肌腱形态学特征。

基于嵌入式系统的实时房颤检测算法研究

目的:设计一种基于嵌入式系统的实时房颤检测算法,辅助房颤的快速诊断和鉴别。方法:首先通过对心电信号进行分析,提取心率变异性指标以及P波平衡性、叠加平均比例2项形态学指标,构建基于支持向量机的房颤检测数学模型,完成上位机算法设计。然后设计主要包括心电采集模块、微控制单元、液晶显示屏和存储器的嵌入式房颤检测设备。再于某院搜集包含11种不同心电节律的3 746例患者的12导心电图数据,并从每名患者的心电数据中提取一段Ⅱ导心电信号建立上位机验证数据集及嵌入式系统测试数据集。在完成上位机算法训练及验证之后,将其移植到嵌入式房颤检测设备中。最后对上位机算法及嵌入式房颤检测设备的房颤检测性能进行评估。结果:上位机算法检测房颤的准确率为93.40%,敏感度为97.85%,特异度为88.83%;嵌入式房颤检测设备的房颤检测准确率为91.37%,敏感度为96.48%,特异度为87.04%。结论:设计的房颤检测算法能够有效区分房颤与多种不同类型的非房颤心电节律,可为基于穿戴式设备的房颤实时监测提供技术支撑。