The value of electron microscopy in the diagnosis of IgA nephropathy

Electron microscopy plays a fundamental role in the evaluation of renal diseases in general. IgA nephropathy represents a heterogeneous disease clinically and morphologically. There are a number of conditions that need to be considered in the differential diagnosis of IgA nephropathy. The renal pathologist must wisely integrate the light microscopic, immunofluorescence, and ultrastructural data when evaluating cases in which IgA nephropathy is a consideration. Electron microscopy can be crucial in providing information either to support a diagnosis of IgA nephropathy or to aid in the diagnosis of one of its mimics.     

The role of electron microscopy in the diagnosis of surgical pathology in the central nervous system

Electron microscopy has played an important role in the diagnosis of surgical pathology and the establishment of new tumor entities and variants in the central nervous system. However, the use of ultrastructural analysis of brain tumors has decreased with the advent of immunohistochemistry. I present here my personal experiences and perspective on the role of electron microscopy in surgical neuropathology.     

Application of low-vacuum scanning electron microscopy for renal biopsy specimens

Low-vacuum scanning electron microscopy (LV-SEM) has been developed which enables the observation of soft, moist, and electrically insulating materials without any pretreatment unlike conventional scanning electron microscopy, in which samples must be solid, dry and usually electrically conductive. The purpose of this study was to assess the usefulness of LV-SEM for renal biopsy specimens. We analyzed 20 renal biopsy samples obtained for diagnostic purposes. The sections were stained with periodic acid methenamine silver to enhance the contrast, and subsequently examined by LV-SEM. LV-SEM showed a precise and fine structure of the glomerulus in both formalin fixed paraffin and glutaraldehyde-osmium tetroxide-fixed epoxy resin sections up to 10,000-fold magnification. The spike formation on the basement membrane was clearly observed in the membranous nephropathy samples. Similarly to transmission electron microscopy, electron dense deposits were observed in the epoxy resin sections of the IgA nephropathy and membranous nephropathy samples. LV-SEM could accurately show various glomerular lesions at high magnification after a simple and rapid processing of the samples. We consider that this is a novel and useful diagnostic tool for renal pathologies.     

Lack of electron microscopy hinders correct renal biopsy diagnosis: A study from India

Electron microscopy (EM) is performed routinely on all native kidney biopsies in the western world. However, in India, it is not regularly performed due to non-availability and financial constraints. The aim of this prospective study was to evaluate the usefulness of routinely performing EM on native kidney biopsies. In order to eliminate selection bias, all consecutive native kidney biopsies were included in this study, provided they had adequate tissue for light, immunofluorescence (IF), and EM. The biopsies were reported on the basis of light and IF microscopy. EM was performed on each case by another pathologist who also independently reviewed the light microscopic slides and IF images. The findings were then reviewed to assess how the ultrastructural features contributed to the primary diagnosis and assigned to one of the following categories: 1. Crucial for diagnosis, 2. Important contribution, or 3. Not required. Of the 115 cases evaluated, EM was crucial in 12% of the cases. In 20% of the cases, it provided important confirmatory information and in the remaining 68% cases, EM was not considered required. This study supports the use of EM as a routine diagnostic tool in the evaluation of native kidney biopsies. There is an urgent need for availability and accessibility of EM in our country.     

肾综合征出血热患者早期骨髓细胞结构异常的研究

目的 观察汉坦病毒(HV)对人体骨髓细胞的作用。方法 应用免疫荧光技术、光镜和电镜细胞学检查对骨髓细胞结构尤其是超微结构进行观察研究，并设对照组。结果 检测了27例肾综合征出血热(HFRS)患者骨髓细胞的病毒抗原，20例呈现阳性。发现粒细胞含HV抗原阳性细胞百分数最高(76％)，其他依次为单核细胞(65％)，淋巴细胞(40％)，巨核细胞(20％)和红细胞(3．7％)。利用光镜、透射电镜和扫描电镜进行细胞学观察发现感染病毒的骨髓细胞、细胞膜和细胞器的损伤明显高于对照组。结论 HV可侵入骨髓细胞中，并对人骨髓细胞具有致病变作用。     

Scanning and transmission electron microscope observations on human gallbladder epithelium

Summary The early development of the human gallbladder epithelium was studied in 25 foetuses with crown-rump (CR) lengths from 6.0 to 22.5 cm by light and scanning and transmission electron microscopy. The PAS-reaction was used to locate cellular mucosubstances.The development could be devided into previllous and villous stages by light microscopy. The incipient formation of villi was observed in the present material at the 12.5 cm stage.Electron microscopically, three stages of development in the gallbladder epithelial cells were noticed. In the first stage, only one epithelial cell type was found. The microvilli were undeveloped, and there were no secretory granules in the epithelial cells.In the second stage, the epithelial cells contained secretory granules. The other characteristics of this stage were pseudopod-like projections on the apical cell surfaces and development of microvilli into a brush border-like structure.In the third stage, the epithelium showed the same zonal construction as that of the adult gallbladder. The apical surface of the epithelial cell was convex, and the microvilli were well developed. There were no pseudopod-like projections on the apical cell surface. The secretory granules were similar to those seen in the normal epithelial cells of the adult gallbladder. Degenerating cells were sometimes seen in this stage. The PAS-reaction was positive in the second and third stages.     

小鼠胚胎肾脏细胞坏死性凋亡的超微结构

目的 观察小鼠胚胎肾脏发育过程中细胞坏死性凋亡的超微结构变化.方法 应用电子显微镜技术对不同胚龄(E12、14、16、18d)胎鼠(各3例)的肾脏的细胞坏死性凋亡进行系统观察.结果 细胞坏死性凋亡确实出现在胚胎肾脏中,它同时具有坏死的细胞质和凋亡的细胞核.细胞肿胀,细胞膜破溃,细胞器也肿胀空泡化.核染色质高密度固缩,边聚,多呈月牙状.细胞凋亡被发现的机会大于坏死性凋亡和细胞胀亡.结论 细胞坏死性凋亡与细胞凋亡及细胞胀亡共同构成了小鼠胚胎肾脏发育过程中的程序性细胞死亡,但坏死性凋亡和胀亡为辅,而以细胞凋亡为主.     

Transformation of synaptic vesicle phenotype in the intramedullary axonal arbors of cat spinal motoneurons following peripheral nerve injury

Permanent transection of a peripheral motor nerve induces a gradual elimination of whole axon collateral systems in the axotomized spinal motoneurons. There is also an initial concurrent decrease in the amount of recurrent inhibition exerted by these arbors in the spinal cord for up to 6 weeks after the injury, whereas the same reflex action returns to normal by the 12-week postoperative state. The aim of the present investigation was to study the fine structure of the intramedullary axonal arbors of axotomized α-motoneurons in the adult cat spinal cord following a permanent peripheral motor nerve lesion. For this purpose, single axotomized α-motoneurons were labeled intracellularly with horseradish peroxidase at 12 weeks after permanent transection of their peripheral motor nerve. The intramedullary portions of their motor axon and axon collateral arbors were first reconstructed at the light microscopic level and subsequently studied ultrastructurally. This study shows that the synaptic contacts made by the intramedullary axon collateral arbors of axotomized motoneurons have undergone a change in synaptic vesicle ultrastructure from spherical and clear vesicles to spherical and dense-cored vesicles at 12 weeks after the transection of their peripheral axons. We suggest that the present transformation in synaptic vesicle fine structure may also correspond to a change in the contents of these boutons. This may, in turn, be responsible for the strengthening and recovery of the recurrent inhibitory reflex action exerted by the axotomized spinal motoneurons following a prolonged permanent motor nerve injury. Electronic Publication     

Value of transmission electron microscopy for primary ciliary dyskinesia diagnosis in the era of molecular medicine: Genetic defects with normal and non-diagnostic ciliary ultrastructure

ABSTRACT

Primary ciliary dyskinesia (PCD) is a genetic disorder causing chronic oto-sino-pulmonary disease. No single diagnostic test will detect all PCD cases. Transmission electron microscopy (TEM) of respiratory cilia was previously considered the gold standard diagnostic test for PCD, but 30% of all PCD cases have either normal ciliary ultrastructure or subtle changes which are non-diagnostic. These cases are identified through alternate diagnostic tests, including nasal nitric oxide measurement, high-speed videomicroscopy analysis, immunofluorescent staining of axonemal proteins, and/or mutation analysis of various PCD causing genes. Autosomal recessive mutations in DNAH11 and HYDIN produce normal TEM ciliary ultrastructure, while mutations in genes encoding for radial spoke head proteins result in some cross-sections with non-diagnostic alterations in the central apparatus interspersed with normal ciliary cross-sections. Mutations in nexin link and dynein regulatory complex genes lead to a collection of different ciliary ultrastructures; mutations in CCDC65, CCDC164, and GAS8 produce normal ciliary ultrastructure, while mutations in CCDC39 and CCDC40 cause absent inner dynein arms and microtubule disorganization in some ciliary cross-sections. Mutations in CCNO and MCIDAS cause near complete absence of respiratory cilia due to defects in generation of multiple cellular basal bodies; however, the scant cilia generated may have normal ultrastructure. Lastly, a syndromic form of PCD with retinal degeneration results in normal ciliary ultrastructure through mutations in the RPGR gene. Clinicians must be aware of these genetic causes of PCD resulting in non-diagnostic TEM ciliary ultrastructure and refrain from using TEM of respiratory cilia as a test to rule out PCD.     

Light and electron microscopic examination of fine-needle aspirates in the preoperative diagnosis of cartilaginous tumors

Twenty-eight patients with chondrogenic tumours--2 chondroblastomas, 4 chondromas, 18 chondrosarcomas, 1 clear-cell chondrosarcoma, and 3 mesenchymal chondrosarcomas--underwent fine-needle aspiration biopsy (FNAB) in the preoperative investigation. The cytologic features in smears were compared with the histopathologic findings in the surgical specimens; in 14 cases they were also compared with the light and electron microscopic findings in resin-embedded fine-needle aspirates. The smears of the vast majority of the classical chondrosarcomas presented features that made possible the FNAB diagnosis of a chondrogenic tumor to be made. In the case of the low-grade chondrosarcomas in particular, which were poorly or moderately cellular in smears and showed chondroblastic cells often in lacunary structures of hyaline matrix, consideration of the clinical presentation, size, location, and roentgenographic appearance was essential for the diagnosis of chondrosarcoma. On the other hand, the high-grade chondrosarcomas presented cytologic features that clearly indicated their malignancy and they usually had a myxoid matrix. The possible differential diagnoses that may arise from the FNAB diagnosis of cartilaginous tumors are discussed. The resin-embedding technique for the light and electron microscopic examination of FNABs, along with the histochemical analysis for the demonstration of sulphated glucosaminoglycans and the immunocytochemistry applied to smears, was found to be of value in the definite diagnosis, especially in the distinction of chondrogenic tumors from chordoma and metastatic mucous-producing carcinoma.     

An electron microscopic study of the pars distalis of the dog adenohypophysis

Summary The parenchymal cells of the pars distalis of the dog adenohypophysis were studied with the electron microscope. Criteria for the differentiation of four cell types included the size and shape of the cells and the size, shape and distribution of organelles and secretory granules. Three secretory granule-containing cells designated as I, II and III were observed. Cell type I was further divided into subtypes (Ia, Ib, Ic) on the basis of the granule size of maximal frequency. A fourth cell type (IV) contained no or only a few secretory granules. It was unique in having a highly irregular shape with cytoplasmic processes extending between the other cell types and also occasionally enclosing follicular cavities.These studies were supported by USPHS training grant, GM-155 and by Public Health Service, GRS grant 5394. The author wishes to thank Dr. J. M. Wolfe and Dr. E. V. Crabill for their valuable assistance during the course of this investigation.     

Diagnostic utility of CD10, CD3 and electron microscopy of renal cortical neoplasms with oncocytic features

No currently defined imaging techniques can reliably distinguish between oncocytoma and epithelial malignant lesions with oncocytic features in the kidney; therefore, patients must undergo resection or, in certain circumstances, biopsy to definitively establish diagnosis. Immunohistochemical staining for CD10 and CD3, evaluation of the staining pattern and intensity, and relevant morphologic appearance are helpful diagnostic tools in discriminating between renal cell carcinoma with oncocytic features and renal oncocytoma. Electron microscopy confirms different ultrastructural components of each neoplastic cell type and correlates with immunohistochemical findings. Accurate determination of the tumor origin would allow for the use of limited nephron sparing and laparoscopic surgical approaches to treat appropriately.     

Mammalian cell nano structures visualized by cryo Hilbert differential contrast transmission electron microscopy

We applied the Hilbert differential contrast phase electron microscopy technique for the first time to mammalian cells, Ptk2 cells. Intracellular architectures such as the cytoskeletal network, membranous organelles, and mitochondria were observed without prior removal of cell membranes or extraction of soluble proteins. The attachment of mitochondria and membrane organelles with microtubules were observed. Microtubules were depolymerized by nocodazole treatment as expected. Thus, Hilbert differential contrast phase electron microscopy of vitrified cells is a nano-scale molecular imaging technique that opens up new vistas for exploring the supramolecular organization of the mammalian cell.     

Simultaneous processing of substrate-dependent monolayer cultures for scanning and transmission electron microscopy

Summary A reliable method is described for processing substrate-dependent cells raised on culture-grade plastic for both scanning (SEM) and transmission electron microscopy (TEM). This technique allows collection of specimens for TEM and SEM from the same culture dish or flask. In this way it is possible to study the surface morphology (SEM) and thin section ultrastructure of cells from contiguous regions of a culture. Specific regions of a culture can be selected and processed so that specimens retain orientation throughout mounting or embedment and sectioning. The method is applicable both to confluent cultures as well as isolated colonies.     

东北梅花鹿卵母细胞中细胞器变化的电镜观察

目的 揭示东北梅花鹿卵母细胞及其细胞器的发育规律。方法 根据梅花鹿卵泡直径大小、透明带的形成、卵泡腔的出现时间把非发情期和发情期卵泡系统分为：原始卵泡、生长卵泡和成熟卵泡3个时期,并利用电镜、目镜测微尺和显微照相技术对各期卵母细胞发育过程中细胞器进行观察（每类卵母细胞观察6～8个）。 结果 1.原始卵泡和生长卵泡前期：线粒体、高尔基体、滑面内质网（SER）、皮质颗粒等细胞器数量不断增加,并逐渐移向皮质区。2.生长卵泡后期和成熟卵泡期：高尔基体及粗面内质网（RER）消失,皮质颗粒开始在质膜下呈线性排列,线粒体向胞质中央区扩散且少嵴圆形线粒体一律转变为带帽线粒体,核仁发生致密化。3.短而粗的微绒毛从初级卵泡卵母细胞开始出现,到次级卵泡卵母细胞时变得密集而细长,三级卵泡期则开始缩短变粗,部分退出透明带。结论 在卵母细胞发育过程中,线粒体的形态、数量及分布的变化与细胞的代谢水平、增殖及分化密切相关;皮质颗粒与高尔基体基本无关联,但却与滑面内质网关系密切;核仁既是RNA的合成场所又是其贮存场所,同时RNA致密化也成为减数分裂恢复的前提。     

Neuropeptide Y immunoreactivity in the cat claustrum: A light- and electron-microscopic investigation

The claustrum is a telencephalic nucleus located ventrolateral to the basal ganglia in the mammalian brain. It has an extensive reciprocal connectivity with most if not all of the cerebral cortex, in particular, primary sensory areas. However, despite renewed and growing interest amongst investigators, there remains a paucity of data concerning its peptidergic profile. The aim of the present study was to examine the presence, morphology, distribution and ultrastructure of neuropeptide Y-immunoreactive (NPY-ir) neurons and fibers in the claustrum of the cat. Ten adult healthy cats from both sexes were used. All animals received human and ethical treatment in accordance with the Principles of Laboratory Animal Care. Subjects were irreversibly anesthetized and transcardially perfused with fixative solution containing glutaraldehyde and paraformaldehyde. Brains were promptly removed, postfixed and sectioned. Slices were incubated with polyclonal anti-NPY antibodies according to the standard avidin–biotin–peroxidase complex method adopted by our Department of Anatomy, Histology and Embryology. NPY-ir neurons and fibers were found to be diffusely distributed throughout the claustrum, with no obvious topographic or functional patterning other than larger numbers in its central/broadest part (stereotaxic planes A12–A16). Neurons were generally classified by diameter into three sizes: small (under 17 μm), medium (17–25 μm) and large (over 25 μm). Staining density is varied with some neurons appearing darker than others. At the electron-microscopic level NPY immunoproduct was observed within neurons, dendrites and terminal boutons, each differing relative to their ultrastructural attributes. Two types of NPY-ir synaptic boutons were found. Lastly, it is of interest to note that gender-specific differences were not observed.     

Light and electron microscopic findings in five cases of cryoglobulinemic glomerulonephritis

Summary Renal tissue from five patients with cryoglobulinemia was studied by light and electron microscopy and immunofluorescence. None of the histologic features observed at the light microscopic level seems to be specific for cryoglobulinemia. Electron microscopic investigations have shown very large electron dense deposits in almost every examined lobule in all cases. The deposits displayed two main patterns; a homogeneous texture in two cases and tubular or annular structures in three cases. The patients with typically structured deposits had IgG-IgM cryoglobulinemia (2 cases) or monoclonal IgM cryoglobulinemia (1 case). The presence of IgM in cryoglobulinemia may be the cause of the peculiar structure of the deposits.     

An electron microscopical study of the development of the teleost heart

Summary An electron microscopic study has been made on the development of the heart of the plaice (Pleuronectes platessa L.) by the examination of tissue taken from fish at the stage when the heart-tube has formed right through the larval life and up two months postmetamorphosis. The process of developments of the heart is essentially the same as that in higher vertebrates but there are certain minor sequential differences with comparable chick tissue. By day 24 (ten days after hatching) the early larval heart has formed which is a trilaminar structure — a layer of myocardium bounded internally by endocardium and externally by epicardium. This condition lasts until the 4a (Ryland) stage with the onset of endocardial invagination into the myocardium which is the criterion distinguishing the late larval heart. The late larval heart lasts throughout metamorphosis of the larva and until two months post-metamorphosis when the total adult heart is assumed. Thus the process of cardiogenesis continues irrespective of hatching and of metamorphosis. This study supports the concept that the epicardium is derived from an extramyocardial source. No results are presented concerning the theory that, in its earliest stages, the myocardium has a secretory function in the production of cardiac jelly, or of myofibrillogenesis in the Teleost myoblast. Stellar configurations of short lengths of newly formed sarcomeres commonly radiate out from Z centres in early myocytes and it is suggested that this is a primitive feature of Teleost myogenesis. There is also a proliferation of mitochondria within the myocardial cells at metamorphosis which may be connected to the subsequent fast growth of the heart in the succeeding two months.     

Standard methods of electron microscopic radioautography

The standard methods of making electron microscopic radioautograms and quantitation of silver grains in our laboratory were presented. Specialized techniques for insoluble or soluble compounds should be employed for demonstrating the synthesis of various macromolecules and the incorporation of various labeled substances. Specimens for electron microscopic radioautography processed under the same conditions can be employed for the quantitation of radioactive substances in subcellular compartments using image analyzers.     

Intrahypothalamic connections: An electron microscopic study in the rat

Summary Terminal degeneration within the hypothalamus was studied by electron microscopy 1 or 2 days (1) after carefully placed microlesions in the arcuate, anterior periventricular, ventromedial, premammillary and posterior hypothalamic nuclei and (2) after microlesions placed in the hypothalamus deafferented 3 weeks earlier.In the median eminence terminal degeneration was found after each of these lesions. Projections from the ventromedial nucleus reach the arcuate, suprachiasmatic, and anterior periventricular nuclei.Projections from the arcuate nucleus terminate in the medial preoptic, anterior periventricular, and ventromedial nuclei.After lesioning the premammillary nuclei degeneration was found in the supraoptic, arcuate, anterior hypothalamic and ventromedial nuclei.