肺癌细胞及其聚苯乙烯微球模型的光散射研究

在生物医学和临床医学领域,许多疾病的诊断和治疗依赖于细胞形态的识别。不同细胞具有不同的形态,这些形态的不同将导致生物组织中光传播特征的变化,更重要的是这将影响细胞的光散射特性。目前,动态光散射理论是动态识别细胞尺寸和形状的最佳方式。细胞主要由细胞质、细胞核和线粒体组成,因此,分析它们的光散射特性对于光学诊断和治疗具有非常重要的意义。设计实验获取了癌细胞和聚苯乙烯球的光散射特性,并利用时域有限差分法建立细胞质模型进行细胞光散射特性仿真。从肺癌细胞的光散射结果可以看出,线粒体对前向散射（0~20）和后向散射（160~180）贡献最大,细胞核对侧向散射（80~100）贡献最大,细胞质对各个角度贡献均等。仿真结果和实验结果基本一致。     

小鼠小肠粘膜中的退变暗细胞

小鼠小肠粘膜中的退变暗细胞梁平周琳瑛陈莲云钟秀容（福建医科大学电镜室，福州３５０００４）电镜下的暗细胞早就被描述，但其本质众说纷纭。近年来有些作者在肿瘤和其他病理组织内见到伴有线粒体肿胀的暗细胞，认为是有别于凋亡、坏死的另一种细胞死亡方式，称之为Ｂ型...     

洋葱细胞周期中线粒体DNA合成的电镜放射自显影研究

许多工作表明,线粒体DNA的合成是在整个细胞周期中不断进行的,但在不同生物细胞周期的不同时相中线粒体DNA合成速度高低不同。过去这方面的研究通常都是用动物和低等植物进行的。本文以洋葱根端细胞为材料,用电镜放射自显影法研究了细胞周期各时相的线粒体DNA合成。幻根在~3H-胸腺嘧啶核苷溶液中培养10分钟,水洗5分钟,按常规制备了电镜自显影标本。有丝分裂间期各对相是按核内染色质集缩的形态特点、细胞板形成的进程和核内银粒的多少确定的。按Baserga(1985)报告,Gl期     

婴儿黑色素神经外胚瘤的电镜观察

婴儿黑色素神经外胚瘤(MNTI)是国际公认的一种罕见疾病。就我们所知,自1918年由Krompecher首先报告此瘤至今,国外仅有90余例报告,国内只有极少个案报告。我院1970年以后,在临床上曾诊治两例经病理检验确诊为这一种瘤的患儿,并对其中一例手术切除的瘤块进行了超微结构研究。肿瘤组织在电镜下可见两种细胞群,一种是含黑色素的细胞,另一种是无黑色素的小园细胞。色素细胞呈多角或长梭形,彼此以上皮连接方式相连,形成细胞团或围成腔隙。有时可见基底膜将有色素的细胞包围。有色素细胞的胞核富于斑块状异染色质,核膜边缘不齐,胞浆比较丰富。胞浆内除见有线粒体、粗面内质网和高尔基复合体外,还存在许多处在不同发育阶段(Ⅱ—Ⅳ期)的黑色素小体。这些小体为园形或呈棒状,常可在棒状小体     

线粒体肌病超微结构特征研究

目的：结合线粒体肌病超微结构变化的特征，探讨该病的病因和可能的发病机制。方法：对2例线粒体肌病患者腓肠肌活检组织进行光镜和电镜超微病理观察。结果：发现病变肌纤维超微结构变化丰富，线粒体内类结晶包涵体形态独特，肌纤维间存在脂滴沉积，糖原颗粒聚集和异形吞噬体。结论：线粒体内不同形态的类结晶包涵体可能代表了不同种蛋白质的堆积，或是同一种蛋白质异常合成的不同时期的表现；脂滴沉积和糖原颗粒的异常增多，是继发于线粒体功能的障碍所致，进而出现形吞噬体的自我保护性反应。     

60Coγ射线辐照对姬松茸菌丝体细胞超微结构的影响

应用透射电子显微镜观察了不同剂量^60Coγ射线辐照的姬松茸菌丝体的细胞超微结构。结果表明：^60Coγ射线辐照引起了姬松茸菌丝体细胞超微结构变化，出现了细胞质壁分离、细胞膜破损、细胞质外流、线粒体形态结构变异、内质网数量减少等现象。研究发现，当0．5kGY〈辐照剂量〈0．75kGY时，细胞壁膜断裂，内含物散布在细胞质中，内质网数目明显减少且不发达，线粒体嵴模糊；而辐照剂量为0．75kGY时，多数细胞中内质网数目增加且发达，线粒体形态发生变化，数量也显著增加，但有的细胞的细胞壁和细胞膜断裂，内含物外流，细胞变成空泡。上述结果表明：^60Coγ射线辐照对姬松茸菌丝体细胞超微结构产生不同程度的损伤，但适当的辐照可增加内质网和线粒体的数量。     

水稻胚乳发育中线粒体定向淀粉质体转变及琥珀酸脱氢酶的研究

以水稻胜泰一号为材料，对其开花后发育前期颖果进行了超微结构观察，查明在某一特定时期线粒体大量转变为淀粉质体。进而对线粒体标志酶-琥珀酸脱氢酶进行了电镜细胞化学定位分析，在胚乳细胞中线粒体的内膜和嵴上均有显著的酶活性，进一步证实胚乳细胞中线粒体转变成淀粉质体的事实。     

低强度激光生物效应与细胞凋亡

低强度激光的生物刺激效应已被众多事实所证实［１］。但其机理尚不清楚。近年来，许多研究揭示细胞凋亡可能在低强度激光生物效应中起着重要作用，本文拟从细胞凋亡这一角度做一概述和探讨。细胞凋亡是细胞对内外信号刺激做出的应答反应，是一种由基因控制的细胞主动死亡过程，有时被称为程序性细胞死亡［２］。随着人们认识的深化，现在越来越多的生物学家认为细胞凋亡在细胞发育、分化和成熟过程中具有特殊的生物学意义，涉及到许多生理病理过程，细胞凋亡是细胞生物体的重要自稳机理之一。它作为细胞固有的主要消亡机理包括两个基本的生…     

水稻矮缩病毒云南、浙江分离株侵染水稻植株的细胞病理比较研究

为探讨水稻矮缩病毒（RDV）不同分离株侵染寄主植物的细胞病理学变化,验证RDV部分基因差异是否引起致病性差异,本文应用超薄切片电镜技术比较观察RDV云南分离株和浙江分离株侵染水稻的细胞病理.结果显示,RDV云南分离株侵染的水稻叶片中充满病毒粒体的细胞呈条带状分布,呈现出明显的侵染中心.在充满病毒粒体的细胞周围,相邻细胞不同程度地病变,叶绿体膜系统消失,部分叶绿体中含有病毒颗粒,线粒体残体及细胞质中有分散或聚集的病毒粒体,细胞核中未见病毒粒体;离侵染中心较远的细胞中亚细胞结构较完整.RDV浙江分离株侵染的水稻叶片中部分细胞充满病毒粒体,无明显的条带状分布,其他细胞病理特征与RDV云南分离株侵染的水稻叶片相似.这些结果表明,RDV不同分离株侵染寄主植株的细胞病理特征无显著差异,对其致病性的差异需进一步研究.     

透射电子显微镜在1798例肾活检病理诊断中作用的评价

肾脏疾病的病理诊断是病理学的一个重要分支，也是肾脏病学不可分割的部分。对肾脏疾病肾活检的病理诊断，除需要有病理学知识外，还必须有免疫组织化学和超微病理学的知识。超微病理学，是应用电子显微镜技术和手段，观察亚细胞结构的病理变化。     

弱精症病人精子线粒体的电镜观察

为了解弱精症精人精子线粒体的超微结构变化,本文对10例弱精症病人,4例健康人（年龄28－37）精液稀释后离心,常规电镜制片,透射电镜观察。结果表明：弱精症患者除了存在精子大小、形态和核形异常外,同时精子内线粒体发生了超微结构的病理性改变,表现为：一是在精子头部或核有病变的精子,其属部线粒体存在数量和分布的异常,出现双层、三层重叠,并发生脊间隙增宽;二是线粒体肿胀、膜电子密度减低、脊间隙扩张并形成微囊;三是出现畸形或巨形线粒体。本文提出对男性不育病人进行精液电镜检查,了解线粒体的超微结构变化,对明确诊断和临床治疗有一定价值。     

Rational Engineering of a Mitochondrial-Mimetic Therapy for Targeted Treatment of Dilated Cardiomyopathy by Precisely Regulating Mitochondrial Homeostasis

Dilated cardiomyopathy (DCM) is a leading cause of heart failure and the most common indication for heart transplantation. Currently, there is still an unmet clinical need in effective therapies for DCM. Herein a mitochondrial-mimetic therapy capable of efficiently targeting the heart, cardiomyocytes, and myocardial mitochondria as well as effectively regulating mitochondrial homeostasis for targeted treatment of DCM is reported. A bioactive conjugate TPT is first synthesized by integrating three functional moieties onto a scaffold, which can assemble into small-size nanomicelles (i.e., TPTN). Intravenously delivered TPTN efficiently accumulates in the heart and mainly localizes in cardiomyocytes and myocardial mitochondria of DCM mice, thereby alleviating DCM. Mechanistically, TPTN inhibits intracellular oxidative stress, alleviates mitochondrial injury, improves mitochondrial dynamics, regulates mitochondrial oxidative phosphorylation, and reduces calpain-1 and NLRP3 inflammasome activation, thus restoring mitochondrial homeostasis and inhibiting adverse cardiac remodeling. By packaging TPTN into outer mitochondrial membrane-derived vesicles, a mitochondrial-mimetic therapy is engineered, which displays significantly enhanced three-level targeting capability to the heart, cardiac cells, and myocardial mitochondria, thereby affording notably potentiated therapeutic effects in DCM mice. Accordingly, the three-level targeting mimetics is promising for targeted treatment of DCM. The findings provide new insight into rational design of precision therapies for mitochondrial dysfunction-associated diseases.     

凋亡神经元线粒体超微结构的形态计量学分析

目的:观察并分析人大脑皮层凋亡神经元线粒体超微结构的形态计量学变化.方法:取21例脑外科手术患者的额叶大脑皮质超薄切片中的正常神经元和凋亡神经元的电镜照片各80张,分为对照组与凋亡组.采用形态计量学方法对两组神经元的细胞体、细胞核、线粒体及细胞质基质灰度进行分析.结果:与正常神经元相比,凋亡神经元线粒体的体密度、面密度、数密度、比膜面明显增大(P＜0.01),比表面无明显改变(P＞0.05),线粒体基质与细胞质基质灰度之差明显增大(P＜0.01).结论:凋亡神经元线粒体未发生明显肿胀或增生,但其内膜和嵴的面积明显增加,基质密度降低.     

肝豆状核变性线粒体超微结构的形态计量学分析

目的:比较肝豆状核变性(hepatolenticular degeneration,Wilson’s disease,WD)与正常肝脏肝细胞线粒体的形态计量学差异。方法:应用透射电镜观察两组肝组织中肝细胞内线粒体并应用图像分析软件计算线粒体的平均周长、平均面积、数密度等。结果:肝豆状核变性肝细胞线粒体平均周长(Bm)、平均面积(Am)均大于正常对照组线粒体,两者差异具有显著性(P0.05),数密度(Nv)差异无统计学意义。结论:肝豆状核变性线粒体发生显著肥大。     

Cytochemical energy-filtering transmission electron microscopy of mitochondrial free radical formation in paraquat cytotoxicity.

The generation of oxygen free radicals was investigated using cytochemistry and its energy-filtering transmission electron microscopy in reference to the toxic mediator for the herbicide paraquat. When isolated intact mitochondria from rat livers were incubated in a medium containing paraquat and NADH, a mitochondrial NADH-quinone oxidoreductase activity generated superoxide anions to cause the destruction of mitochondria which resulted in cell death. The superoxide anions were immediately converted into hydrogen peroxide, which then formed cerium perhydroxide deposits in the presence of cerium ions and precipitated on the outer surface of the mitochondrial outer membrane. This localization was also specifically identified by energy spectral imaging and image-electron energy loss spectral analyses. Precipitation reaction was scavenged by the addition of either cytochrome c or catalase and inhibited by dicoumarol (an inhibitor of NAD(P)H-quinone oxidoreductases). These cytochemical energy-filtering transmission electron microscopic results indicated that paraquat generated free radicals from the outer membrane of mitochondria.     

High‐Fidelity Trapping of Spatial–Temporal Mitochondria with Rational Design of Aggregation‐Induced Emission Probes

High‐fidelity trapping of mitochondrial dynamic activity is critical to value cellular functions and forecast disease but lack of spatial–temporal probes. Given that commercial mitochondria probes suffering from low photostability, aggregation‐caused quenching effect, and limited signal‐to‐noise ratio from fluorescence “always on” in the process of targeting mitochondria, here, the rational design strategy of a novel aggregation‐induced emission (AIE) molecular motif and unique insight into the high‐fidelity targeting of mitochondria is reported, thereby illustrating the relationship between tailoring molecular aggregation state and mitochondrial targeting ability. This study focuses on how to exactly modulate the hydrophilicity and the aggregated state for realizing “off‐on” fluorescence, as well as matching the charge density to go across the cell membrane for mitochondrial targeting. Probe tricyano‐methylene‐pyridine (TCM‐1) exhibits an unprecedented high‐fidelity feedback on spatial–temporal mitochondrial information with several advantages such as “off‐on” near‐infrared characteristic, high targeting capacity, favorable biocompatibility, as well as excellent photostability. TCM‐1 also produces reactive oxygen species in situ for image‐guided photodynamic anticancer therapy. Through unraveling the relationship between tuning molecular aggregation behavior and organelle‐specific targeting ability, for the first time, a unique guide is provided in designing AIE‐active probes to explore the hydrophilicity and membrane potential for targeting subcellular organelles.     

Starvation induces the formation of giant mitochondria in gastric parietal cells of guinea pigs

Mitochondria occasionally increase in size in response to metabolic injury. Numerous studies have reported giant mitochondria in patients with various diseases and animals with metabolic injuries, but there are few reports on giant mitochondria in normal cells under physiological conditions. Here, we report giant mitochondria in normal gastric parietal cells. Stomachs of guinea pigs fed freely, fasted or fasted and then injected with histamine were processed for electron microscopy. Giant mitochondria >2 microm in the diameter of their major axis were observed in resting-type parietal cells in the gastric glands of animals fasted for 60-72 h, whereas acid-secreting-type parietal cells found in those fed ad libitum did not contain giant mitochondria. Giant mitochondria showed unusual structures, especially in their cristae: they contained closely packed, tubular and concentric cristae as well as amorphous and pleomorphic inclusion bodies in their matrix. We observed giant mitochondria consisting of several segments, suggesting the fusion of several normal-sized mitochondria. Histamine injection decreased in a frequency of giant mitochondria in accordance with a decrease in a frequency of resting-type parietal cells. This is the first report of giant mitochondria in gastric parietal cells under physiological or near physiological conditions. Gastric parietal cells might be a good model for examining mitochondrial fusion and fission in a physiological state accompanied by the morphological change of the cells in the membrane system from an acid-secreting to resting type.     

Varied cytochrome oxidase activities of the alveolar type I, type II and type III cells in rat lungs: quantitative cytochemistry

Cytochemically demonstrated cytochrome oxidase activities in mitochondria of rat pulmonary alveolar epithelial cells were quantitatively compared. As the standardized procedures, lungs were fixed for 10 min at 4 degrees C with 2% pure glutaraldehyde, and incubated for different times at 37 degrees C in a medium containing 1.0 mg/ml 3,3'-diaminobenzidine-4HCl, 1 mg/ml cytochrome c, 0.1 mg/ml catalase, 7% sucrose, and 0.1 M phosphate buffer, pH 7.4. Electron micrographs were then obtained, and the densities of the reaction deposits in the mitochondrial intermembrane-intracristal space were measured in an image analyzer, and were plotted in terms of time in minutes. The initial velocity (maximal rate) of the activity expressed as deposit accumulation rate (% area/60 min) filling the mitochondrial intermembrane-intracristal space of Type I, Type II and Type III cells was 40, 130 and 9.3, respectively. These results indicated that mitochondria are varied in the intensity of cytochrome oxidase activity among 3 types of pulmonary alveolar epithelial cells, and that the image-analyzing measurement of the accumulation rate of reaction product may be useful for quantitative analysis of enzyme activity, in particular, in the cells which are difficult to isolate from complex tissues.     

Red AIE Luminogens with Tunable Organelle Specific Anchoring for Live Cell Dynamic Super Resolution Imaging

Lysosomes and mitochondria play an important role in maintaining cell homeostasis. Visualizing the long-term activities of lysosomes and mitochondria on the nanometer scale in live cells is essential for further understanding their functions but remains challenging due to the limitations of existing fluorescent probes, such as aggregation-caused quenching (ACQ) effect, limited signal-to-noise ratio from fluorescence “always on” in the process of targeting organelle and poor photobleaching resistance. Herein, two efficient red-emitting aggregation-induced emission (AIE) luminogens are reported, which showed “off-on” fluorescence characteristic and specific lysosomes as well as mitochondria targeting capability. Owing to their AIE characteristics, a Stokes’ shift larger than 100 nm, good biocompatibility, and excellent photostability, the AIE luminogens have been successfully utilized for high fidelity imaging of lysosomes and mitochondria. By virtue of these two probes, stimulated emission depletion (STED) images of dynamic lysosomal fusion and mitochondrial fission with a high resolution of 65.6 nm are obtained. Furthermore, the interactions between lysosomes and mitochondria in the process of mitophagy are recorded. This study also provides practical guidance for designing specific organelle targeting probes to support live cell dynamic super-resolution imaging.