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Results for “scanning electron microscope”

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At least 883 records · Page 49Linked to original sources

PubMed2004

Scanning electron microscopic observations on adult Spirocerca lupi (Nematoda: Spirurida, Thelaziidae).

Scanning electron microscopy was used to study the surface ultrastructure of adult worms of Spirocerca lupi. At the anterior end of both sexes, the mouth is hexagonal, without definite lips. Around the mouth, two pairs of submedian cephalic papillae and two lateral amphids are present. There is a pair of lateral cervical papillae. At the anterior end of the body, on the ventral side, an excretory pore is seen. In the female, the vulva is located anteriorly and the tail is blunt, with a pair of subterminal phasmids. The male tail is spiral, with four pairs of preanal papillae, a single large median preanal papilla on the anterior lip of the cloacal aperture, two pairs of postanal papillae, four pairs of tiny papillae near the tip of the tail and two subterminal phasmids. The cuticle shows an abnormal tumour-like mass in two cases.

Animals↗

PubMed1982

Scanning electron microscope observation of the swarming phenomenon of Vibrio parahaemolyticus.

Scanning electron microscopy was used to study the production of lateral flagella and the swarming phenomenon in Vibrio parahaemolyticus. Differences in the size and diameter of the sheathed, polar flagellum and lateral flagella were apparent in these preparations. Swarming of V. parahaemolyticus was found to be similar to the swarming of Proteus spp. in that swarm cells which are heavily flagellated and elongated are formed.

Flagella↗

PubMed1978

Scanning electron microscope study of herpes simplex virus experimental disciform keratitis.

Scanning electron microscopy of the endothelium of experimental disciform keratitis revealed corneal endothelial changes which distinguished disciform oedema from the more progressive stages of disciform keratitis. The endothelium of corneas with disciform oedema were wholly intact and characterised by subtle morphological alterations. In contrast, the more progressive stages of disciform keratitis were characterised by massive destruction and denudation of the endothelium. The significance of these observations is discussed.

Animals↗

PubMed1989

[Connecting pattern of rabbit surface buccal epithelial cells: a scanning electron microscopic study].

Rabbit buccal epithelial cells were studied by scanning electron microscopy. The cell surface was covered with type 4 microridges. The surface was also segmented by cellular borders and attached borders. Small area enclosed by the attached border was often elevated from the surrounding areas. The intervals of the microridges of this small protrusion were narrower than those of the surrounding area and resembled those of type 5 microridges. These findings suggest that exposure of the cell membrane to the external environment induces morphological changes in the microridges. The area surrounded by cellular borders, which was considered to have become small protrusions, was also observed. These observations suggest a staggered lamination of cell stacks and the penetration of a part of cell surface of the lower layer into the cellular space of the upper layer, forming an interdigitation. This cell arrangement is considered to enhance the strength of the binding of the cells.

Animals↗

PubMed1991

Scanning electron microscopic study of pulp stones in human permanent teeth.

Scanning electron microscopy was used to examine pulp stones which are small calcified formations found in the coronal and/or radicular part of the dental pulp. Pulp stones range considerably in size and shape. Most are round or oval but others can be irregular and may correspond to a reduced duplicate of the pulp chamber anatomy. Both free and attached pulp stones were observed. The surface aspect was variable and frequently exhibited large resorption zones. Three characteristic features were observed on fractures: a) no characteristic organization where the mineralized mass is compact and homogeneous, b) a concentric architecture around an initiating central core, and c) a linear orientation along the pulp axis showing mineralized fibres and vessels. The findings suggest that the presence or absence of tubules should not be the sole factor for denticle classification since tubules can be also observed in "false" pulp stones. Cellular oval lacunae connected by long extensions were also found. Various stages of mineralization were seen, in particular, a deposition of fine needle shaped crystals on a collagenous matrix, and the fusion of numerous small calcospherules to the mineralized mass.

Calcium Sulfate↗

PubMed1989

Scanning electron microscopic study of the red pulp of ferret spleen.

Scanning electron microscopy of the red pulp of ferret spleen showed areas of relatively wide splenic cord and rather poorly developed splenic sinuses of two different types. The inner aspect of most sinuses was covered with rod-shaped cells running in the longitudinal direction of the sinus. Stomata of these sinuses were recognized between the rod-like cells in a relatively regular lattice-like arrangement. The lining of other sinuses showed characteristics of the poorly differentiated sinuses, having a remarkable irregularity in form, size, and distribution of the lining cells and the stomata. The outer surface of the splenic sinuses was covered with attenuated reticular cell processes supporting the sinus. Sheathed capillaries which have a well-developed sheath structure were frequently found in the cordal area. Cordal capillaries were exclusively open into labyrinthine reticular tissue space of the cord with a funnel-shaped or a perforated saccular or ampullar terminal.

Animals↗

PubMed1985

Scanning electron microscopic studies of Paracoccidioides brasiliensis in the yeast phase.

Scanning electron microscopy of four different Paracoccidioides brasiliensis isolates in the yeast phase revealed that mother cells generating multiple, spherically shaped buds may be firmly or tenuously associated with their progeny whereas elongated buds remain attached to the mother cell through stem-like structures and may represent early stages of hypha formation. The yeast cell surfaces were covered with a delicate network of microfibrillar components.

Microscopy, Electron, Scanning↗

PubMed1980

Scanning electron microscopic study of microcrystals implicated in human rheumatic diseases.

Scanning electron microscopy has been used in conjunction with wavelength dispersive X-Ray spectroscopy and in correlation with X-Ray diffraction to define the populations of crystals present in rheumatic diseases. Microcrystals of monosodium urate, triclinic and monoclinic calcium pyrophosphate dihydrate, apatite, calcium hydrogen phosphate dihydrate and corticosteroids, among others, have been found in synovial fluid, in the intraarticular tissues (fibrocartilage, cartilage, and synovial membrane), and in the periarticular tissues (tendons and ectopic calcifications). Scanning electron microscopy in conjunction with wavelength dispersive X-Ray spectroscopy has made it possible to detect microcrystals, even isolated, to describe their morphologies, and to study their relations with the cells of the synovial fluid and with the collagenous and cellular structures of the synovial membrane and of the cartilage. It cannot replace X-Ray diffraction for the conclusive identification of microcrystals, but it can certainly help to improve the analysis of the various populations of crystals present in articular and periarticular rheumatic diseases.

Arthritis, Rheumatoid↗

PubMed1975

[Trichorrhexis congenita. Scanning electron microscopic studies on a congenital disorder of hair growth].

1. A congenital disturbance of hair growth belonging to the "trichorrhexis nodosa" group is described. Clinically, abnormal hair fragility since birth was the leading symptom. There was no detectable amino-aciduria. 2. The scanning electron microscope (SEM) reveals localized alterations of the hair shafts. These are irregularities of the cuticular pattern, partial fractures of the cortical filament bundles, and complete fractures with broom-like splintering of the hair ends. 3. There is no generally accepted definition of the symptom or the disease of "trichorrhexis nodosa". Further SEM analysis and collection of such hair anomalies is proposed. As in the case described here no "nodes" of the hair shaft were observed, it is presented as "trichorrhexis conginita".

Child, Preschool↗

PubMed1992

Scanning electron microscopic observations of Anopheles albimanus (Diptera: Culicidae) eggs.

To investigate the existence of subspecies of Anopheles albimanus Wiedeman in southern Mexico, the egg morphology of specimens obtained from several field populations and from insectary-adapted colonies of uniform pupal phenotype was examined. Scanning electron microscopic observations have shown that the eggs of An. albimanus are polymorphic in respect to the size and shape of their floats, but not in their ornamentation. Four types of eggs were found. Differences in the proportion of the various morphological types were statistically significant, although proportions of egg types were variable among individuals within the same population. These observations are suggestive of distinctive populations and warrant further studies using more sensitive methods to investigate sibling species in An. albimanus sensu lato.

Animals↗

PubMed1983

Scanning electron microscopic study of the intestinal mucosa of an Indian freshwater adult major carp, Labeo rohita (Hamilton).

Fine anatomical structures of the different regions (viz., anterior, middle and posterior) of the intestinal mucosa in adult Labeo rohita (Hamilton) have been studied by using Scanning Electron Microscope (SEM). Surface mucosal modifications of the anterior and the middle of the intestine not only increase the luminal surface by 2-4 times but serve also the storage function of the ingested food due to the absence of stomach in the fish studied. Fine anatomical structures of the columnar epithelial and goblet cells of the mucosa have been studied in detail. The height and complexity of the microridges on the luminal end of each columnar cells in the various regions vary greatly probably due to the functional variations of the region concerned. Communication between the columnar cells and the sub-mucosal layer through the basement membrane is effected by circular orifices. A pear-shaped apical portion provided with prominent microridges of the goblet cell probably allows the mechanical stress to develop for the accumulation of secretory mucins.

Animals↗

PubMed1984

Scanning electron microscope studies of lymphatic tissues with special reference to the structure of the reticulum.

Reticular cells of the lymph nodule in the rabbit appendix and the lymphatic pulp including the germinal center in the dog mesenteric lymph node were observed under the scanning electron microscope after removal of free cells. Three dimensional architecture and arrangement of the reticular cells varied by regions in the lymph nodule. The appendix lymph nodule encapsulated with the endothelium of lymphatic sinuses was subdivided into two regions: (1) a central region of sparsely arranged stellate cells with coarse processes and (2) a peripheral zone of densely arranged stellate cells with many delicate processes. In the lymph node, the germinal center contained a loosely formed network of delicate stellate cells. Peripheral reticular cells of the nodule were thread-like, extending concentrically around the germinal center or along the sinus wall. Many lateral bridges of the threads occurred segmentally. The reticular framework of the medullary cord formed spongy meshes by anastomoses of stellate cells. Cytoplasmic perforations were observed in the sinus wall of the medullary cord. Those may be for lymphocyte migration.

Animals↗

PubMed1994

[Scanning electron microscopic observation on altered fenestration of the choriocapillaris in sodium iodate-treated rats].

Fenestration of the choriocapillaris may be lost and regained in various pathologic conditions. The purpose of this study was to observe the gradual disappearance of fenestrae with the scanning electron microscope. Pigmented rats were treated with an intravenous injection of sodium iodate. Changes in the choriocapillaris were produced by damaging retinal pigment epithelium. The eyes were processed for styrene embedded cracking on the third, fifth, and seventh days. Dense clusters of fenestrae were seen at the luminal surface facing retina on the third day. These clusters were surrounded by protrusion of cellular surface. The clusters of fenestrae were smaller with some variation in size on the fifth and seventh days. The protrusion between the clusters became flatter and wider. Some endothelial cells had a flat surface with tiny clusters of fenestrae. Although there was loss of fenestrae with smaller clusters and some variation in size, the tendency of the fenestrae to cluster was sustained in the same way as during the reformation of fenestrae in the choriocapillaris after laser photocoagulation.

Animals↗

PubMed1990

Ultrastructural investigation of granulation tissues on the osteoarthritic femoral head. A scanning electron microscopic and transmission electron microscopic study.

From the femoral heads of nine cases of advanced osteoarthritis of hip joint, three categories of granulation tissues with different colors (bright red, dark-red and white granulation tissues) and texture were obtained. After processing, the specimens were observed under scanning electron microscope and transmission electron microscope. With transformation of the granulation tissues from bright red to white, the collagen fibers therein contained gradually changed from fine to thick ones. Nevertheless, the cellular components in these three types of granulation tissues always possessed the characteristics of both fibroblasts and chondrocytes, i.e., fibroblastic configuration with pericellular Type I collagen fibrils bearing 64 nm periodicity; and chondrocytic scallop-shaped cytoplasmic membrane with intracytoplasmic fat droplets and glycogen granules and pericellular Type II collagen fibrils. All these indicated that in osteoarthritis of hip joints, the granulation tissues of the femoral heads transformed eventually into fibrocartilage, irrespective of their color and texture.

Femur Head↗

PubMed1978

Scanning electron microscopic study of the otolithic organs in the bichir (Polypterus bichir) and shovel-nose sturgeon (Scaphirhynchus platorynchus).

The anatomy and ultrastructure of the sacculus, lagena, and utriculus of the ear of Polypterus bichir and Scaphirhynchus platorynchus were studied using the scanning electron microscope. The otolithic organs each contain a single dense calcareous otolith in close contact with a sensory epithelium (macula). The maculae have sensory hair cells typical of those found in other vertebrates, surrounded by microvilli-covered supporting cells. The hair cells on each macula are divided into several groups, with all of the cells in each group morphologically polarized in the same direction. The cells of the utricular macula in both species are divided into opposing groups in a pattern similar to that found in other vertebrates. The saccular and lagenar maculae are located in a single large chamber in both species. In Scaphirhychus the two maculae are on the same plane, while in Polypterus they are at right angles to one another. The hair cells on the saccular maculae of both species are divided into two oppositely oriented groups. In Scaphirhynchus the cells on the posterior half of the macula are oriented dorsally on the dorsal half of the macula and ventrally on the ventral half. The anterior region of the macula is rotated and the cells of the dorsal and ventral groups are shifted so that they are oriented on the animal's horizon plane. A similar pattern is found in Polypterus, except that this macula is shaped like a "J" with the vertical portion of the J having horizontal cells and the bottom portion vertical cells. The lagenar maculae in both species have dorsally oriented cells on the anterior side of the macula and ventrally oriented cells on the posterior half of the macula. While these data are not sufficient for clarifying the taxonomic relationship between the two species studied, it is clear that the ears in these species have a number of significant differences from the teleost ear that could have functional and/or taxonomic significance.

Animals↗

PubMed1994

Study of the apices of human permanent teeth with the use of a scanning electron microscope.

The apical region of the roots of 38 maxillary incisors, 25 mandibular incisors, 29 maxillary second premolars, 92 mandibular first and second premolars, 12 maxillary first molars, and 17 mandibular first molars were prepared and studied with the use of a scanning electron microscope. The number and size of the main apical foramina, their distance from the anatomic apex, and the existence and size of accessory foramina were recorded, summarized, and statistically analyzed. More than one main foramen was observed in all groups except for the palatal root of maxillary molars and the distal root of mandibular molars. Accessory foramina were also observed in all groups of teeth. The distal roots of mandibular molars had the largest size main foramen (mean value, 392 microns), whereas the maxillary premolars had the largest accessory foramina (mean value, 53.4 microns) and the most complicated apical morphologic makeup. The distance of the main foramen from the anatomic apex never exceeded 1 mm. The highest values were observed at the mandibular incisors (978 microns), the distal root of mandibular molars (818 microns), and the upper premolars (816 microns). All values showed satisfactory fitting to normal distribution.

Chi-Square Distribution↗

PubMed1989

Scanning electron microscope appearance of the enamel/composite/bracket areas using different methods of surface enamel treatment, composite mix and bracket loading.

Minimal plaque retention on and around orthodontic brackets is of paramount importance if iatrogenic tooth damage is to be avoided. This study made use of the scanning electron microscope to examine how variations in composite mix and finishing affected the smoothness and adaptation at the bracket, composite, and enamel interfaces. The study indicated that the optimum choice for good composite/enamel adaptation with a smooth composite surface and good composite/bracket adaptation involves the use of an intermediate unfilled resin layer, a paste/liquid mix of composite placed on a bracket which is optimally loaded, and no excess composite removed with an instrument.

Acid Etching, Dental↗

PubMed1979

[Comparative studies on Trichomonas vaginalis in the scanning electron microscope].

Different strains of Trichomonas vaginalis isolated from the vagina of women with trichomoniasis were used in these investigations. The cultures were carried out on modified CPLM and Roiron media. Individuals at the highest phase of logarithmic growth underwent the observation. Preparations to be evaluated in scanning electron microscope ( JEOL - JSM -S1) were made from a condensed culture containing 500,000 individuals per ml. Each time, microscopic pictures obtained after washing, demucination and various fixation procedures and after lyophylisation were compared to each other. The pictures obtained from smears taken from the vagina of women with trichomoniasis were compared, too. Special attention was paid to the behaviour of the surface and motion organelles of the parasite.

Biometry↗