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PubMedDate not supplied

Scanning electron microscopy of normal cells, dyskaryotic cells and malignant cells exfoliated from the uterine cervix.

The same exfoliated benign, dyskaryotic and malignant cervical cells were observed by light microscopy and scanning electron microscopy in order to investigate the reflection of the course of malignancy in the surface ultrastructure. The surface ultrastructural features (microridges and microvilli) of normal squamous cells and metaplastic cells showed regularities, with an approximately even thickness, length and distribution of microvilli. In dyskaryotic cells of the superficial type, the microridgelike structure was retained, and some regularity of the microvilli remained. However, in dyskaryotic cells of the deep-layer type, the microvillous surface ultrastructure had a pronounced irregularity and diversity. In malignant cells, there was unevenness in the projections and in the thickness of the cytoplasm, and these cells presented, as a whole, a bizarre appearance. The surface ultrastructure of malignant cells thus reflected a strong atypia of the cytoplasm.

Carcinoma in Situ↗
PubMedDate not supplied

[Electron microscopy of the intestinal mucosa in a case of lymphangiectasis].

The morphology of the intestinal mucosa was reviewed using light microscopy and transmission electron microscopy from a two year-old male patient with protein losing primary intestinal lyphangiectasis. Diagnostic studies ruled out recognized forms of secondary intestinal lymphangiectasia (e.g cardiac, hepatic, renal diseases or lymphoreticular cancer). Furthermore, certain features distinguish this patient from the secondary type: decreased immunoglobulin and albumin levels, lymphocytopenia, chylous ascitis and delated lymphatics on small-bowel biopsy.

Child, Preschool↗
PubMed1987

Low magnification transmission electron microscopy in diagnostic pathology.

Transmission electron microscopy examination of selected diagnostic specimens, that is, renal and nerve biopsies, can be greatly facilitated by the implementation of slot grid preparations that are inherently devoid of any grid bars. Such preparations are conducive to screening and photography at both low and intermediate modes of magnification without any apparent loss of resolution. The use of this technique in diagnostic electron microscopy is simplified by sequential en bloc staining with both uranyl and lead salts.

Animals↗
PubMed1988

Plant protoplasts immobilized in calcium alginate: a simple method of preparing fragile cells for transmission electron microscopy.

A simple method for electron microscopic preparation of plant protoplasts is described. The main problems in preparing these fragile protoplasts for electron microscopy have been cell collapse due to steep gradients between protoplasts and fixatives and unacceptable loss of material during the many steps of the procedure. These problems may be solved by immobilization of the protoplasts in calcium alginate beads. The free diffusion properties of this gel prevent steep gradients. The beads also simplify handling and prevent loss of material. Protoplasts isolated from hypocotyls of rape, Brassica napus (var. Niklas), have been used as a model system. Transmission electron microscopy of the immobilized protoplasts osmotically stabilized with glucose demonstrated adequate structural and ultrastructural preservation.

Alginates↗
PubMed1969

Measurement of protein concentration by quantitative electron microscopy.

The method of quantitative electron microscopy was applied to the measurement of protein concentration in thin sections. The human erythrocyte was selected as a model because of its apparently uniform protein concentration. Phosphotungstic acid (PTA) in aqueous solution was used as a reversible stain for protein, and PTA-stained Dowex resin spheres were embedded along with the red cells as standards for measurement of section thickness. The mass of stain removed from a given area of sectioned red cell by buffer (pH 7.4) was measured by quantitative electron microscopy. From the stoichiometry of the reaction between PTA and red cell protein established in this study, the amount of protein present in the measured area was calculated. From this amount of protein and the measured thickness, the concentration of protein was calculated and expressed as g/100 ml, for comparison with the clinical laboratory value for hemoglobin. Groups of red cells from the same sample were measured on 3 different days and their mean values (g/100 ml +/- SD) were 29 +/- 3.9, 30 +/- 2.7, and 33 +/- 4.6, compared to the clinical laboratory value of 32.1 g/100 ml packed cells, after correction for volume change and protein loss during fixation.

Blood Proteins↗
PubMed1992

Preparation of muscle samples for comparative electron microscopy.

The interpretation of muscle structure by scanning electron microscopy (SEM) has not been consistent among various studies. Consequently, the literature is confusing with respect to the identity of T-tubules, transverse ridges, Z-disks, and intermyofibrillar connections. The objective of this research was to evaluate the effects of different methods of sample preparation and imaging on ultrastructural details of previously identified transverse structures and intermyofibrillar connections and to verify or disprove the commonality of these structures under different viewing conditions. Scanning electron microscopy coupled with a cold stage, SEM at room temperature, and transmission electron microscopy (TEM) of thin sections were most appropriate for exposing detail of inter- and intracellular structures and for measuring sarcomere length and spacing of intermyofibrillar connections. Scanning electron microscopy of samples mounted on a cold stage, fractured, and sublimed provided excellent images of meat and muscle ultrastructure and may be used in correlative microscopy. Sarcomere length and spacing between intermyofibrillar connections were similar among most specimen preparation techniques and were affected similarly by heat treatments. Results indicate that the regularly spaced transverse structures viewed by conventional SEM and the intermyofibrillar connections viewed by low-temperature SEM are Z-disks.

Animals↗
PubMed1999

DNA bending due to specific p53 and p53 core domain-DNA interactions visualized by electron microscopy.

We have used transmission electron microscopy to analyze the specificity and the extent of DNA bending upon binding of full-length wild-type human tumor suppressor protein p53 (p53) and the p53 core domain (p53CD) encoding amino acid residues 94-312, to linear double-stranded DNA bearing the consensus sequence 5'-AGACATGCCTAGACATGCCT-3' (p53CON). Both proteins interacted with high specificity and efficiency with the recognition sequence in the presence of 50 mM KCl at low temperature ( approximately 4 degrees C) while the p53CD also exhibits a strong and specific interaction at physiological temperature. Specific complex formation did not result in an apparent reduction of the DNA contour length. The interaction of p53 and the p53CD with p53CON induced a noticeable salt-dependent bending of the DNA axis. According to quantitative analysis with folded Gaussian distributions, the bending induced by p53 varied from approximately 40 degrees to 48 degrees upon decreasing of the KCl concentration from 50 mM to approximately 1 mM in the mounting buffer used for adsorption of the complexes to the carbon film surface. The p53CD bent DNA by 35-37 degrees for all salt concentrations used in the mounting buffer. The bending angle of the p53/DNA complex under low salt conditions showed a somewhat broader distribution (sigma approximately 39 degrees ) than at high salt concentration (sigma approximately 31 degrees ) or for p53CD (sigma approximately 24-27 degrees ). Together, these results demonstrate that the p53CD has a dominant role in complex formation and that the complexes formed both by p53 and p53CD under moderate salt conditions are similar. However, the dependence of the bending parameters on ambient conditions suggest that the segments flanking the p53CD contribute to complex formation as well. The problems associated with the analysis of bending angles in electron microscopy experiments are discussed.

Base Sequence↗
PubMed2001

Transmission electron microscopy studies of squeeze cast Al-AlN composites.

Aluminium-matrix composites containing approximately 45 vol.% AlN particles were fabricated by melt infiltration of aluminium into an AlN preform under a pressure up to 130 MPa. Three types of aluminium alloy (2024, 6060 and 5754) were used. The as-prepared composites were studied by light microscopy, scanning and transmission electron microscopies, and energy-dispersive X-ray spectroscopy. As a result of the melt infiltration process, the composites are very dense and the microstructure shows a homogeneous distribution of the reinforcement. The interfaces are clean with very little porosity. Composites with 2024 and 6060 matrices were carefully studied by transmission electron microscopy (TEM) and high resolution electron microscopy (HREM) after heat treatments. Dislocation density in the matrix of the reinforced material increases due to the difference in thermal expansion coefficients of aluminium alloys and AlN. This can induce an accelerated ageing response of the coherent and semicoherent precipitations of age-hardened matrices. This behaviour has been studied in the 2024 and 6060 composites by using microhardness measurements and TEM. Reactions between the AlN reinforcement and aluminium matrices (6060 and 5754) were observed and analysed by TEM. Matrices containing some of magnesium display a MgAl2O4 spinel formation at the AlN/matrix interface. The spinel formation is probably due to the reaction between magnesium of the matrix and the thin Al2O3 layer on the AlN surfaces. This reaction can affect the mechanical behaviour of the composite infiltrated with the 5754 matrix. This has been confirmed by overageing some samples at high temperatures (300 degrees C and 550 degrees C) for 10 days in order to emphasize the interfacial reactions.

Journal Article↗
PubMedDate not supplied

Fine needle aspiration of schwannomas. Value of electron microscopy and immunocytochemistry in the preoperative diagnosis.

In the absence of Verocay bodies, the cytologic appearance of schwannomas can be quite nonspecific, with the differential diagnosis including a number of spindle cell lesions. The diagnostic accuracy can be enhanced by the use of electron microscopy (EM) and immunocytochemistry; both techniques are easily applicable to aspirated material. Six cases of schwannoma, diagnosed as such preoperatively by the application of these techniques, are reported. Only two of the cases showed Verocay bodies on light microscopy. Electron microscopy, performed on four cases, revealed a complex arrangement of long cell processes, with scattered desmosomelike structures, a prominent focally reduplicated basal lamina and long-spacing collagen. All of the cases showed positive staining for S-100 protein.

Adult↗
PubMed1979

Intercellular junctions in FANFT-induced carcinomas of rat urinary bladder in tissue culture: in situ thin-section, freeze-fracture, and scanning electron microscopy studies.

This paper describes a set of simple methods for comparative light and electron microscopy studies on tissue cultured tumour cells derived from both noninvasive and invasive carcinogen-induced rat urinary bladder carcinomas. Cells are grown on Thermanox plastic coverslips and fixed in situ. Each plastic coverslip is then divided with scissors into four parts: the first is processed for light microscopy, the second for thin-section electron microscopy, the third for freeze-fracture electron microscopy, and the fourth for scanning electron microscopy. In some experiments, portions of the culture which have first been examined by light microscopy are subsequently prepared for electron microscopy. In this way, the culture conditions are kept constant and comparison of structural features (i.e. intercellular junctions) by several preparative techniques is possible. Noninvasive and invasive rat bladder tumour cells, characterized by numerous pleomorphic microvilli, have normal zonulae occludentes at the apices of lateral surfaces of tumour cells in all cultures. In some areas of invasive tumour cells, occludens junctions are focally attenuated, consisting of only one or two strands, and occasionally the strands are discontinuous. Gap junctions, type PF-1, as well as numerous demosomes are present in all cell lines. Thus, intercellular junctions in noninvasive and invasive rate bladder epithelial cell lines bear a striking resemblance to those previously described in the comparable solid primary tumours. These culture systems may be useful for studying factors which influence the formation of intercellular junctions during malignant transformation.

Animals↗
PubMed1993

[Diagnostic value of electron microscopy on epithelial tumors of the ovary].

The study on transmission electron microscopy (TEM) and scanning electron microscopy (SEM) in 52 cases of ovarian epithelial tumors (OET) was presented. The characteristic features of ultrastructure and cell surface structure of different types of OET, also the diagnostic features of cancer cells were determined and discussed. It has a great value in differentiation of histologic types of OET and in early diagnosis of cancer. In 3 cases of borderline malignant tumor, some malignant cells, which were impossible to distinguish by light microscopy, were discovered by TEM and SEM. The diagnostic value of electron microscopy in early malignancy of tumors is more important.

Adenocarcinoma, Mucinous↗
PubMedDate not supplied

Role of electron microscopy in transplant renal pathology.

The crucial role that electron microscopy plays in diagnostic renal pathology is undisputed. By allowing recognition of findings not identifiable by light microscopic evaluation, electron microscopy has contributed significantly to the understanding of renal diseases and has proven to be of unquestionable value in many diagnostic situations. However, the percentage of cases in which electron microscopic examination adds important information that is either key for establishing or confirming a diagnosis or provides valuable data that influence patient's management remains controversial. This figure depends on the renal biopsy service that is surveyed, but it is reported that on the average ultrastructural evaluation is of value in approximately 30 to 45% of the cases. Correct interpretation of a renal biopsy depends on the ability to correlate light, immunofluorescence, and ultrastructural findings. In contrast, the role of electron microscopy in the examination of renal transplant specimens remains controversial. Many centers do not use routine electron microscopy to examine these specimens and insist that there are only a few specific indications that require ultrastructural evaluation. There is general agreement among renal pathologists that electron microscopy is of importance in the evaluation of renal specimens from patients with proteinuria to distinguish between transplant glomerulopathy, recurrent or de novo glomerulonephritis in order to correctly manage these patients and predict survival of the graft. The other possible indications are much more controversial. This paper summarizes and critically reviews the literature available on this subject and defines recommendations based on the information available at the current time.

Biomarkers↗
PubMed1994

Triple retinal infection with human immunodeficiency virus type 1, cytomegalovirus, and herpes simplex virus type 1. Light and electron microscopy, immunohistochemistry, and in situ hybridization.

PURPOSE: This report describes the histopathologic and virologic findings of the retina from a 55-year-old bisexual patient with the acquired immune deficiency syndrome (AIDS), who had concurrent human immunodeficiency virus type 1 (HIV-1), cytomegalovirus (CMV), and herpes simplex virus type 1 (HSV-1) retinitis, and was treated with ganciclovir. METHODS: The eyes were obtained at autopsy and processed for light microscopy and transmission electron microscopy. Immunohistochemical stains for HSV-1, CMV, HIV-1, varicella zoster virus, and glial fibrillary acidic protein were carried out using the peroxidase-antiperoxidase and streptavidin-biotin-alkaline phosphatase techniques. For in situ hybridization, a radiolabeled CMV DNA probe (Eco-RI-Y fragment of strain AD 169) was used. RESULTS: Results of histopathologic examination showed a full-thickness necrotizing retinitis with cytomegalic and herpes viral intranuclear inclusions in cells of the neurosensory retina, retinal vascular endothelium, and the retinal pigment epithelium. Some areas of the retina were replaced by glial tissue. The choroid contained only a few chronic inflammatory cells. Immunoperoxidase studies disclosed CMV antigens diffusely distributed throughout all layers of the retina and the retinal pigment epithelium. Herpes simplex virus type 1 antigens were present in retinal cells and the retinal vascular endothelium. Human immunodeficiency virus type 1 antigens were found in mononuclear cells in all layers of the sensory retina. Dual infections with HIV-1 and CMV of individual multinucleated giant cells of glial origin were demonstrated immunohistochemically. Transmission electron microscopy showed herpes viral particles in the vascular endothelium of the retinal vessels and the choriocapillaris. Human immunodeficiency virus particles were identified in the endothelium of the choriocapillaris. CONCLUSIONS: The possibility of multiple viral infections of the retina, mimicking classic CMV retinitis, should be considered in the clinical and histologic differential diagnosis of necrotizing retinitis in patients with AIDS.

Antibodies, Viral↗
PubMed2005

The role of electron microscopy in neuropathology.

The electron microscope has been an essential instrument for elucidating the morphology of cells and tissue. Fine structural investigation of nervous tissue has disclosed numerous new findings, which were once invisible. In this communication I present my personal perspective on the role of electron microscopy in neuropathology through the presentation of selected electron microscopic projects engaged in our institution. These include brain edema, structural analysis of the myelin in the central nervous system, endodermal cysts in the central nervous system, aberrant synaptic development, toxoplasmosis in AIDS, and Hirano bodies.

Acquired Immunodeficiency Syndrome↗
PubMed1996

X-ray diffraction, electron microscopy, and Fourier transform infrared spectroscopy of apatite crystals isolated from chicken and bovine calcified cartilage.

Apatite crystals of the calcified zone of the subarticular cartilaginous growth plates of the long bones of young growing chickens and calves were isolated by low temperature reaction with hydrazine and plasma ashing and examined by electron microscopy, electron diffraction and microprobe analysis, and computer-generated deconvolution of the spectra obtained by Fourier transform infrared spectroscopy. The crystal habit was that of wide, very thin, relatively long rectangular plates, which tended to form small clusters of crystals, possibly because reaction with hydrazine alone did not remove all of the organic matrix constituents. Further reaction with low power plasma ashing released more of the isolated crystals although to a lesser extent than was possible with bone. Stereograms of the small clusters showed that many of the crystals in the small isolated aggregates of crystals were bent and/or curved. Together with the resultant overlap of individual adjacent crystals, they also produced images of sharp, very dense lines, reminiscent of the electron-dense needle or rod-like appearances frequently observed by transmission electron microscopy of thin sections of calcified cartilage and thought to represent the habit of the apatite crystals. No true rod or needle-like crystals were observed in the isolated crystals. Although the overall general apatitic structure of the apatite crystals was similar to that of the apatitic crystals of bone, the individual crystals were significantly larger than those of bone from the same specimen, and there were small but significant differences in the concentrations of acid phosphate and carbonate groups and in their short range order.

Animals↗
PubMedDate not supplied

Diagnostic electron microscopy: future development.

When the electron microscope was initially developed, pathologists thought that it would become the ultimate diagnostic tool for tumor diagnosis because the structure of subcellular organelles could be visualized. However, the role of diagnostic electron microscopy in tumor diagnosis diminished rapidly when it was noted that there were a finite number of diagnostic subcellular organelles and that immunohistochemistry could yield the answer to questions which related to tumor diagnosis more rapidly and cheaply. If diagnostic EM is to remain a viable entity, its future role in tumor diagnosis lies in exploiting the relevance of the correlation between structure and function of subcellular organelles. This correlation between structure and function of subcellular organelles is best accomplished in an environment in which the recent technologic advances in electronics are incorporated into the electron microscopy laboratory.

Clinical Laboratory Techniques↗
PubMed2000

Development of an X-ray photoemission electron microscopy system with multi-probes, and its application to surface imaging at static and dynamic states.

We have developed a new X-ray photoemission electron microscopy system combined with low energy electron microscopy, photoemission electron microscopy, mirror electron microscopy (MEM), secondary electron emission microscopy (SEEM) and Auger electron emission microscopy, which provides multi-angle information on the distribution and change of element, chemical state, structure, etc. at solid surfaces under the working conditions such as high temperature and gas atmosphere. The performance of each microscopical method was examined and typical images are presented. The dynamic behaviour of fabricated surfaces has been imaged in real time by SEEM and MEM.

Journal Article↗