IGMI组织注射SEM观察提示胰岛素

 @@ 传统知识认为,由胰岛(pancreatic islet)B细胞合成,释放入胰组织液中的多肽胰岛素(polypeptide insulin)或激素分泌颗粒,马上透过有孔毛细血管壁进入血液,通过肝门静脉转运而发挥作用.值得指出,胰组织内既存在毛细血管,也分布有丰富的毛细淋巴管;毛细淋巴管的管径和通透性,远远大于毛细血管.大分子多肽胰岛素何以进入门脉血液而不进入淋巴呢?新生胰岛素通过门脉经肝时不会被灭活吗?这些疑虑激励我们探讨和澄清多肽激素在细胞外的正常转运途径或规律.     

IGMI组织注射SEM观察提示胰岛素正常转运经淋巴而非门脉

传统知识认为 ,由胰岛 (ｐａｎｃｒｅａｔｉｃｉｓｌｅｔ)Ｂ细胞合成 ,释放入胰组织液中的多肽胰岛素(ｐｏｌｙｐｅｐｔｉｄｅｉｎｓｕｌｉｎ)或激素分泌颗粒 ,马上透过有孔毛细血管壁进入血液 ,通过肝门静脉转运而发挥作用。值得指出 ,胰组织内既存在毛细血管 ,也分布有丰富的毛细淋巴管 ;毛细淋巴管的管径和通透性 ,远远大于毛细血管。大分子多肽胰岛素何以进入门脉血液而不进入淋巴呢 ?新生胰岛素通过门脉经肝时不会被灭活吗 ?这些疑虑激励我们探讨和澄清多肽激素在细胞外的正常转运途径或规律。1 材料与方法应用免疫胶体金 (1 0ｎｍ)标…     

微波辐射固定及其在免疫金标记技术中的应用

应用微波辐射快速固定大鼠胰腺组织和白血病病人骨髓细胞悬液,再按常规制作电镜超薄切片。包埋后超薄切片免疫金标记β细胞中的胰岛素分泌颗粒显示组织细胞结构清晰,标记率高,(图1)。骨髓细胞悬液包埋前免疫金标记和酶反应定位血小板表面糖蛋白(GPⅡb/Ⅲa)和胞浆内过氧化物酶均呈现阳性结果(图2)。电镜观察结果表明,经微波辐射固定的生物样品能较好地保存细胞的超微结构,抗原性及其酶活性。根据多次反复试验,我们取得的经验是,在进行微波辐射固定生物样品时,电镜样品固定温度和时间以26～28℃,15秒为宜。由于微波辐射加热温度升高很快,我们采用在炉室内四角放置四个盛有     

人体及动物不同组织中肥大细胞颗粒超微结构的比较研究

运用透射电镜对人体正常皮肤、肺、心肌及萎缩性胃炎胃粘膜、垂体肿瘤、淋巴管瘤;大肠正常皮肤、舌粘膜、腹腔及小肠,化学致癌剂诱发肝癌、舌粘膜、腹腔及小鼠,化学致癌剂诱发肝癌以及血吸虫感染家兔肝、脾等组织中肥大细胞（MC）胸浆内颗粒的超微结构进行了对比观察,结果表明：存在于人体肺及胃粘膜中的大多数MC颗粒均具有独特 亚结构,它们由多个呈旋涡状排列的筒状结构组成,其它组织中的MC颗粒则主要呈电子致密均质状,前者属MC^T,后者为MC^CT。这种结构特征在正常及病理性组织中并无明显差异。因此,人体MC颗粒的超微结构特征可以作为区别两类不同表型MC的标志之一。与人体组织中MC相反,大鼠体内各部组织中MC颗粒超微结构基本一致,而与人体MC^T颗粒类似。因此,单从颗粒的超微结构不能区分大鼠MC表型,血吸虫感染家兔肝、脾中的MC颗粒超微结构则与上述观察均不相同,颗粒内或见有电子透明的大的结晶样结构或见有许多电子透明的小点状结构。后者有的广布于整个颗粒之中,有的则沿颗粒周边分布,沿有一些颗粒则由单膜包绕,内含多个致密亚单位。     

肾综合征出血热发病中不溶性免疫复合物的作用

目的：为确定肾综合征出血热（HFRS）不溶性免疫复合物（IC）在发病中的作用。方法：本研究采用HFRS病毒抗原和相应抗体在体外制备成特异性的不溶性IC,经尾静脉注射入小鼠体内,而后应用免疫荧光组织化学方法结合激光扫描共聚焦显微镜和电子显微镜观察了病毒抗原及IC在各主要脏器的分布及其致病变作用。结果：IC注射后24h,主要见于血管系统如肝血窦和肾小球毛细血管之中。IC注射72h后,IC主要存在于肾小球基底膜部位以及血管系膜中,呈细小或粗大的颗粒状。肾小球毛细血管中红细胞明确阳性。某些血管腔中仍充满荧光物质,有些荧光物质位于足细胞的胞质内。在肾小球周围的部分肾小管上皮细胞可有IC,包括抗原和C3。不溶性IC注射后168h（7d）,大多数肾小球结构接近正常,几乎看不到特异性的荧光。电镜观察发现病变以肾小球为主,发现系膜细胞伸出明显的胞质突起,并延伸至内皮和基膜之间。系膜细胞也有增生,可见沿细胞膜分布的中等数量的吞饮小泡以及胞浆中小的溶酶体颗粒。免疫沉积物可出现在肾小球系膜基质区,为不规则形,常聚集成团块状,呈散在分布,有时可见于内皮下、上皮下和/或基膜内。肾小球基膜呈不规则延伸、增厚,呈花斑状,并形成裂隙。IC注射后24h,某些毛细血管袢管腔中有血小板聚集。注射后72h,血小板聚集已不明显。某些毛细血管内皮细胞损伤严重,内皮细胞肿胀,部分区域内皮细胞突起脱落,基膜裸露。内皮细胞伸出许多绒毛状突起,互相交织融合形成拱状结构。胞浆中游离核糖体和粗面内质网增多。有些内皮细胞的胞质形成泡状结构。毛细血管管腔中充满一些电子致密的沉积物,并且这些电子致密物可通过内皮缺损与肾小球毛细血管基膜物质相连。肾小球囊壁层基膜外侧裸露,有胶原纤维形成。足细胞肿胀,突起融     

大鼠急性出血坏死性胰腺炎时肾损害的超微结构研究

胰胆管内逆行注射5%牛磺胆酸钠建立大鼠急性出血坏死性胰腺炎（AHNP）动物模型,用光镜和电镜动态观察肾脏在不同时期的病理形态学变化,从形态学的角度探讨AHNP所引起的肾脏损伤机制;结果发现AHNP时肾脏的病理形态学改变表现为不同程度的肾小球毛细血管腔内红细胞堆积以及血小板和纤维素的析出粘集,毛细血管基底膜增厚,足细胞的足突融合,肾间质血管内新鲜血栓形成,以及肾小管上皮细胞变性、坏死,小管内出现蛋白管型或红细胞管型等.本实验结果提示在AHNP时可伴有明显的肾脏微循环损伤,微循环障碍可能是引起或加重AHNP相关肾损害的重要原因之一.     

Application of backscattered electron imaging to enzyme histochemistry of lymphatic capillaries.

A backscattered electron imaging (BEI) in scanning electron microscope (SEM) was applied to the observation of lymphatic capillaries on cryostat-cut tissue blocks of monkey stomachs with enzyme-histochemical method. The differentiation of the lymphatics from blood capillaries was established on cryostat sections using 5'-nucleotidase (5'-Nase)-alkaline phosphatase double-staining method. On the tissue surface, 5'-Nase-positive lymphatic capillary walls were seen as highlights with good contrast and resolution by the BEI. A pair of the backscattered and secondary electron imaging in the same area clearly reveals the correlation between the enzyme activity and surface structure of the tissue. Observation of stereo-pairs of the BEIs increases the information on the three-dimensional architecture of lymphatic capillaries. The present study demonstrates the applicability of the BEI of 5'-Nase reaction to SEM histochemistry of lymphatic capillaries stained with heavy metal.     

Three-dimensional reconstruction by scanning electron microscopy from serial epoxy resin semi-thin sections after ion-etching

Three-dimensional reconstruction was performed using scanning electron micrographs of serial semi-thin sections of Epon embedded specimens. Connective tissue in a rabbit ear chamber was fixed in glutaraldehyde and osmium tetroxide, and then embedded in Epon. One-microm-thick serial sections were cut with a diamond knife, mounted on glass slides and stained with toluidine blue. After observation with a light microscope, the sections were ion-etched with an ion-spatter coater. Following double staining with uranyl acetate and lead citrate, the consecutive sections were ion-coated with platinum. Each serial section was photographed with a scanning electron microscope. Profiles of a blood vessel and fibroblasts were digitized with a computer and computer reconstruction of the blood vessel was performed. Three-dimensional reconstructions showed that the newly formed blood vessel was a cylinder-like, bare endothelial tube with a rather smooth outer surface. Fibroblasts were situated around the endothelial tube. Several openings were found in the endothelial tube, suggesting the morphological feature of high permeability and fragility in newly formed blood vessels. The availability of three-dimensional reconstruction from scanning electron micrographs of serial semi-thin epoxy resin sections was discussed; structures of interest can be reconstructed (1) quickly and easily, (2) without skilful techniques, and (3) almost at the level of ultrastructure.     

Enzyme-histochemical demonstration of lymphatic vessels in the golden hamster periodontium: an attempt to reactivate the 5'-nucleotidase activity with Mg++ ion supply

Enzyme-histochemical demonstration of lymphatic vessels in the golden hamster periodontium was performed on cryostat sections using the 5'-nucleotidase (5'-Nase) staining method by light microscopy and backscattered electron imaging of scanning electron microscopy. The inhibition of the 5'-Nase activity by decalcification was cancelled by the Mg++ ion supply. The reaction products of 5'-Nase activity were produced on the lymphatic endothelial cells and the tubular structures of lymphatic vessels were seen as highlights by backscattered electron imaging. The invasion of 5'-Nase-positive lymphatic vessels into the alveolar bone from the periodontium was found in the present study.     

Development of an active targeting liposome encapsulated with high-density colloidal gold for transmission electron microscopy

Active targeting of the liposome is an attractive strategy for drug delivery and in vivo bio-imaging. We previously reported the specific accumulation of Sialyl Lewis X (SLX) liposome to inflamed tissue in arthritic model mice or tumor-bearing mice. SLX-liposome encapsulation with fluorescent substances allows for the visualization of these liposomes by the time-dependent transvascular accumulation of fluorescent signals in the histological sections. In the present study, we developed a new SLX-liposome encapsulated with colloidal gold for transmission electron microscopic observation. We herein describe the characterization of the colloidal gold-loaded SLX-liposomes and demonstrate its specific targeting to the endothelial cells of tumor blood vessels in tumor-bearing mice.     

Polymer Scaffolds for Small‐Diameter Vascular Tissue Engineering

To better engineer small‐diameter blood vessels, a few types of novel scaffolds are fabricated from biodegradable poly(L ‐lactic acid) (PLLA) by means of thermally induced phase‐separation (TIPS) techniques. By utilizing the differences in thermal conductivities of the mold materials and using benzene as the solvent scaffolds with oriented gradient microtubular structures in the axial or radial direction can be created. The porosity, tubular size, and the orientational direction of the microtubules can be controlled by the polymer concentration, the TIPS temperature, and by utilizing materials of different thermal conductivities. These gradient microtubular structures facilitate cell seeding and mass transfer for cell growth and function. Nanofibrous scaffolds with an oriented and interconnected microtubular pore network are also developed by a one‐step TIPS method using a benzene/tetrahydrofuran mixture as the solvent without the need for porogen materials. The structural features of such scaffolds can be conveniently adjusted by varying the solvent ratio, phase‐separation temperature, and polymer concentration to mimic the nanofibrous features of an extracellular matrix. These scaffolds were fabricated for the tissue engineering of small‐diameter blood vessels by utilizing their advantageous structural features to facilitate blood‐vessel regeneration.     

Correlative light microscopy, scanning electron microscopy, and transmission electron microscopy of osmium-macerated biological tissues

A method facilitating correlation of light microscopic (LM), scanning electron microscopic (SEM) and transmission electron microscopic (TEM) images was developed. Rat kidney and heart were initially subjected to the osmium maceration procedure and then embedded in acrylic resin. Semithin sections of the tissue blocks were first provided for LM and then examined by SEM after resin removal. Furthermore, the ultrathin sections adjacent to the semithin sections were observed by TEM. The three-dimensional images of intracellular organelles provided an informative adjunct to LM and TEM.     

Morphological and histochemical analyses of living mouse livers by new 'cryobiopsy' technique

A new 'cryobiopsy' (CB) technique has been invented for freezing the functioning livers of living mice in vivo without stopping their blood circulation. Livers of anesthetized mice were pinched off with pre-cooled CB forceps and immediately plunged into isopentane-propane cryogen. They were routinely freeze-substituted in acetone containing paraformaldehyde for light microscopy (LM) or osmium tetroxide for scanning electron microscopy (SEM). By freeze-fracturing some of them with a scalpel in liquid nitrogen before the freeze-substitution, well-preserved tissue areas were exposed only for SEM. They were either embedded in paraffin wax for LM or infiltrated with t-butyl alcohol followed by freeze-drying for SEM. Serial paraffin sections were stained with hematoxylin-eosin (HE) or histochemical periodic acid-Schiff (PAS) reaction. By HE-staining, the tissue surface areas were often compressed with the CB forceps and sinusoidal erythrocytes became aggregated side by side. In slightly deeper tissue areas, however, hepatic sinusoids were widely open with flowing erythrocytes. Lots of PAS-reaction products were well preserved in hepatocytes of the CB specimens. On the contrary, they were unevenly distributed in hepatocytes of conventionally quick-frozen specimens, and often lost in those of the conventionally dehydrated specimens. By SEM, some cell organelles, such as mitochondria and endoplasmic reticulum, and also dilated fenestrae of endothelial cells, open Disse's spaces and bile canaliculi appeared to be under normal blood circulation in the prepared CB samples. The new CB technique would be easy and useful for repeated examination of functioning organs of a living animal.     

考虑多普勒效应的脉冲无意调制特征比较

脉内无意调制特征是雷达特定辐射源识别的基础和关键。该文在考虑多普勒效应的条件下,对工程中常用的脉内无意调频与无意调相特征进行了可分性比较。首先给出了高斯白噪声以及中、高信噪比条件下,脉内信号相位的简化观测模型;在分析以往关于两种待比较特征的提取流程的基础上,给出了特征定义;然后利用基于离散度矩阵的可分性判据对两种特征进行了理论的可分性比较。结果显示,脉内无意调相特征对噪声的鲁棒性相对更强。仿真实验以及104个实测雷达的个体识别试验验证了上述结果。