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At least 361 records · Page 20Linked to original sources
PubMed1979

Virus-cell interactions as seen by scanning electron microscopy.

Scanning electron microscopy (SEM) has been used during the past few years to determine surface alterations of cells infected with a variety of RNA and DNA viruses. Infection of different cultured cells by RNA and DNA viruses usually revealed dramatic shape changes with surface alterations. The most frequent changes seen were "rounding up" of cells and the development of surface microprojections such as ruffles and microvilli. In the light of available knowledge, suggestions are made in this review for future SEM studies in this field with more sensitive methodologies, which will enable even better characterization of virus-induced cell surface changes.

Animals↗
PubMed2002

Noncytopathic hepatitis A virus induces surface alterations in LLC-MK2 cells revealed by thin sections, negative staining, and scanning electron microscopy.

Previous electron microscope studies of ultrastructural events during hepatitis A virus replication in experimentally infected cells have used only ultrathin section techniques. Nevertheless, no important differences were observed between infected and uninfected cells. This study was carried out using scanning electron microscopy and negative staining of whole LLC-MK2 cells grown directly on grids covered with support membranes, and then infected with an hepatitis A virus strain. Thin sections of infected and uninfected controls were also analyzed. An intricate web of projections forming a net between cell interfaces was observed only in infected cells. Some of these projections were more than 700 nm long and had ballooning tips. Nevertheless, HAV particles were not visualized in the infected cells.

Animals↗
PubMed2004

The in vitro effect of albendazole, ivermectin, diethylcarbamazine, and their combinations against infective third-stage larvae of nocturnally subperiodic Brugia malayi (Narathiwat strain): scanning electron microscopy.

Scanning electron microscopy (SEM) was employed to observe the effects of ivermectin (IVM), diethylcarbamazine (DEC), and albendazole (ALB) alone, and the drugs in combination (ALB+IVM and ALB+DEC) against infective third stage larvae (L3) of nocturnally subperiodic (NSP) Brugia malayi (Narathiwat strain) in vitro. IVM, at a concentration of 10(-4) M, killed L3 within 1-2 h. The SEM data showed damage to the L3 surface and loss of regular cuticular annulations. The cuticles were grooved in the middle region of the body. In comparison with normal L3 before treatment with IVM, the cuticular surface showed transversed striations with periodic annulations. The result demonstrated that IVM showed a larvicidal activity against L3 of NSP B. malayi cultivated in vitro. Compared with those larvae in the control group, the treated larvae had no morphological changes in the cuticular surface at the head, body, and tail regions after cultivation with all drugs alone, and in their combinations at a concentration of 10(-5) M for 7 d. In this system, and at that concentration, only the larvae cultured with ALB alone remained highly motile. Although no morphological changes had been observed by SEM, those drugs used alone (IVM and DEC) and in combinations (ALB+IVM and ALB+DEC), reduced larval motility throughout the experiments at a concentration of 10(-5) M. The minimum lethal concentration (MIC) of IVM against NSP B. malayi was 10(-4) M.

Albendazole↗
PubMed1992

Blood vessel architecture in lymph nodes of the dog viewed by scanning electron microscopy.

Scanning electron microscopy was used to investigate the submicroscopic organization of the blood vessels of dog lymph nodes (LN). The LN vessels were casted by systemic perfusion of the animals vasculature with two resins of distinct viscosity. This resulted in the retrieval of two types of LN vascular replicas that depicted either the arterial blood system alone (methacrylate casting) or both the arterial and venous blood systems (Mercox casting). We found that the dog LN showed a significantly higher density of arterial vessels in the cortex than in the medulla. In the cortical domain, a subcapsular layer stood out because of its rich content in arterial capillaries. The use of the high-resolution resin (mercox) resulted in excellent structural detail of the luminal surface of the LN vessels that allowed a clear distinction between arterioles and venules based on the geometrical pattern of the imprints left in the replicas by the nuclei of endothelial cells. At the cortex-medulla frontier, most arterioles showed narrowings of their lumen that suggested the existence of sphincters at this level. Our findings document that the microanatomical arrangement of blood vessels in the LN of the dog is different from that of LN from other mammals studied so far, in particular from rodents where vascular-poor microdomains have been reported in the LN cortex. The arteriolar sphincters that we detected at the innermost zone of the cortex may represent the structural counterpart of the physiological modulation of the blood supply of the cortex exerted by arterial branches coming from the hilus.

Animals↗
PubMed1988

[Effect of a modification of the medium on the structure of bacterial cells based on electron microscopy data].

Electron microscopy was used to study the interactions between microorganisms and the culture medium in the presence of modifying agents. Temperature-dependent changes in the intensity of water-glycerin exchange between the cells and the medium are demonstrated, which is of interest for the optimization of the conditions of using protectors, as well as for the study of the permeability of cell membranes.

Culture Media↗
PubMed1987

The fine structure of the human placental villus as revealed by scanning electron microscopy.

Scanning electron microscopy of the placenta has a history of only twenty years. During that time, however, there have been dramatic advances in instrument technology coupled with the refinement of preparative techniques designed to reduce fixation artifacts to a minimum. As a result many of the early claims must be amended or suitably qualified, and this is one aim of the present review. Much new data on the internal structure of the placental villus is also presented. By means of the partial digestion technique it is now possible to describe the three dimensional configuration of the various components of the villous tree. This review will consider these sequentially, starting externally with the gross morphology of the villi and ending with replicas of the fetal vasculature produced by corrosion casting.

Chorionic Villi↗
PubMed1988

[Characteristics of the microstructure of biliary calculi based on data from scanning electron microscopy].

Scanning electron microscopy was employed to study cholelithic microstructure. Irrespective of the chemical composition, the gall-stones demonstrated the presence of a cementing matrix composed of micellar-vesicular particles occurring either in aggregates or regularly spreading along the facets about the surface of crystalloid structures. There appeared to be a close relationship between the latter and the particles which are, viz., vesicles, responsible for the plane and margin epitaxy of the cryslalloid structures. Any cholesterol deposits are lipoprotein-like particles or their derivatives, appearing as micellar-vesicular particles in case of choleliths.

Cholelithiasis↗
PubMed1986

Fuchs' heterochromic cyclitis: an electron microscopy study.

Electron microscopy and computerised image analysis of iris biopsies in five cases of Fuchs' heterochromic cyclitis showed that depigmentation was due to significant reduction in deep stromal melanocyte numbers and a decrease in melanosomal size, in the presence of more mast cells and an infiltrate of plasma cells and lymphocytes. Anterior border cells appeared sparse and their melanosomes showed similar differences when compared to five normally pigmented controls. Pigment epithelium melanosomes did not alter in size.

Adult↗
PubMed1986

Dissection technique for cochleas prepared for scanning electron microscopy.

Scanning electron microscopy (SEM) permits a three-dimensional study of the surface morphology of the organ of Corti that is very useful in evaluating the condition of the apical end of the hair cells and the stereocilia. However, some laboratories have experienced problems with curling of the basilar membrane during critical point drying of cochlear specimens prepared for SEM evaluation using the Murakami or osmium thiocarbohydrazide-procedures. This curling of the basilar membrane can obstruct the view of the reticular lamina and the ciliary ends of the hair cells. We have used a dissection method, referred to as the anchor technique, to overcome basilar membrane curling. This technique removes all the structures above the reticular lamina but leaves the basilar membrane attached to the spiral ligament and the lateral bone to which the spiral ligament is anchored. Individual cochlear turns are dissected in this manner and mounted on the same examination stub for SEM evaluation. Maintenance of the lateral attachment of the basilar membrane requires additional dissection time but eliminates the problem of curling during critical point drying. An additional benefit is that mounting the individual turns on the same examination stub facilitates evaluation and photomicroscopy of the surface morphology. The anchor technique has been used successfully on the guinea pig and should be appropriate for most mammalian cochleas.

Animals↗
PubMed1986

[Types of mitochondria destruction in the cardiac myocyte (from the data of scanning electron microscopy)].

Scanning electron microscopy has revealed three types of myocardial mitochondria degradation in intact rabbit heart: desquamation of the external membrane, mitochondria swelling with their following destruction, mini-focal ulceration of mitochondrial external membranes. There was a clear-cut daily and seasonal dynamics of the three types of degradation. Mitochondria degradation was much more pronounced in the fibrillating than in intact heart.

Animals↗
PubMed1985

Interaction between glioma cells and normal brain tissue in organ culture studied by scanning electron microscopy.

Scanning electron microscopy was employed to investigate cocultures between normal rat brain fragments and spheroids consisting of rat glioma cells. Lamellipodia were seen to arise from tumor cells at the border between the two structures and touch the surface of the fragment. Cytoplasmic extensions from malignant cells appeared to penetrate into the brain fragment. Leading lamellae were extended from the tumor cells as they migrated along the normal surface and gradually covered the fragment. Tumor cells formed broad foot-plates against the normal surface. No alterations of the brain fragment were observed ahead of the tumor cells. Thus there were specific changes of the surface microarchitecture of the malignant cells, but not of the normal brain tissue.

Animals↗
PubMed1979

Surface ultrastructure of polycystic ovaries as viewed by electron microscopy.

Scanning electron microscopy was used to observe surface fine structure of germinal epithelium and granulosa cells of human ovaries from 24 patients with polycystic ovaries and primary infertility. Synthetic LH-RH was administered intravenously and serum LH was measured at frequent intervals before and after LH-RH injection. The PCO patients were arbitrarily classified into two groups on the basis of ovarian morphology: typical PCO (Type I) with greater LH response than the lower LH response of a typical PCO (Type II). The germinal epithelium which did not completely cover the surface of the normal ovary was characterized by patchy areas of cells with and without dense microvilli. In normal preovulatory follicles, most granulosa cells were polyhedral in shape with smooth surfaces, whereas those facing the follicular cavity were elongated and flattened and were covered with material having a filamentous/reticular texture. In PCO the germinal epithelium surrounding the whole surface possessed dense microvilli, solitary cilia, and blebs, resembling the fetal ovary. In normal ovaries, the follicular cells were uniform in size and shape with microvilli and evaginations. The PCO cells have irregular size and shape with few microvilli.

Adult↗
PubMed1984

[Study of the surface of cytolytic T-lymphocytes by scanning electron microscopy].

Scanning electron microscopy revealed three types of cytolytic T lymphocytes (CTL) interacting with target cells (TC). The type I cells occurred as smooth spherical lymphocytes with single microvilli; the type II rounded or oval cells were uniformly covered with microvilli; the type III cells were marked by an irregular shape, were densely covered with microvilli, while their surface was folded or tuberous. Within the first several minutes after absorption the surface of TC was largely covered by the type I lymphocytes. The proportion of the type III cells rose with the time of interaction. At the beginning it was 8-9%, reaching 30-71% after 30-60 minutes of incubation. It is assumed that the 3 types of the cells described mirror 3 stages of CTL activation. The increase in number of microvilli and appearance of the membranous folds may be a consequence of exocytosis and incorporation of the membrane of secretory granules into the plasma membrane of lymphocytes. The data obtained support the authors' assumption about the secretory mechanism of the action of CTL, whose contact with TC stimulated secretion activation.

Animals↗
PubMed1981

Surface topography and other characteristics of non-transformed and carcinogen transformed C3H/10T 1/2 cells in mitosis, as revealed by quantitative scanning electron microscopy.

Scanning electron microscopy (SEM) has been used for the characterization of the different phases of mitosis in normal and transformed C3H/10T 1/2 cells after the stages had been confirmed by light microscopy. Our findings suggest that it is only possible to separate the different phases of mitosis by SEM after having evaluated a great number of cells and after having established the SEM features for the light microscopically identified mitotic phases (Feulgen staining). The main finding in the study is that both the normal and all three types of transformed cells, type I, II and III, have the same shape in the different stages of mitosis but that transformed cells seem to exhibit a larger number of pleomorphic microvilli than do non-transformed cells. We also found that in contrast to the other mitotic phases, prophase cells have a very low concentration of microvilli in the nuclear area.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1977

The presence of fine elastin fibrils within the elastin fibre observed by scanning electron microscopy.

Scanning electron microscopy of critical point dried, enzymically and chemically purified fetal and adult elastin fibres from bovine ligamentum nuchae has shown that the fibres are composed of fine elastin fibrils (110-130nm diameter). In the fetal tissue the elastin fibres were of relatively uniform thickness and did not bifurcate, but in the adult, much thicker, branching fibres were present. It would appear that, during maturation of the elastin fibre, thickening is the result of the aggregation of many fine fibrils, and bifurcations result form bundles of such fibrils crossing over from one fibre to another.

Animals↗
PubMed1995

Comparison of cell sediment and surface grown "test plaque" using scanning electron microscopy.

Scanning electron microscopy was used to compare the morphology, integrity and distribution of bacterial cells in a test plaque grown on the surface of enamel with that of the cell sediment plaque routinely used in a short-term intraoral caries model. Cultures of S. mutans IB-1600 or S. sobrinus 6715-13 were grown in complex media supplemented with either 2.0% sucrose (glucan plaque) or 0.2% glucose (non-glucan plaque). Cell sediment (CS) plaque was prepared by centrifuging the cultures after incubation, recovering the cell sediment, and spreading it on Metricel membrane filter paper. Surface grown (SG) plaque was prepared by suspending saliva-coated bovine enamel in the culture medium, incubating, and recovering the enamel assembly with bacterial accumulations. Cell morphology and integrity, as well as the appearance of glucan-like material produced by the cells, was similar in both CS and SG test plaques. The cell distribution however, varied in the SG plaque from extremes of all cells to all glucan, whereas the cell sediment plaque was more uniform in cell distribution. A highly standardized test plaque minimizes variability in the intraoral caries model. These findings support the contention that the bacterial cells in a cell sediment plaque are similar in morphology, integrity and glucan production to surface grown plaque, and have the added advantage of uniform distribution, which makes the cell sediment plaque more appropriate for intraoral caries model studies.

Animals↗