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The purpose of this scanning electron microscope study was to observe the interface between dentin and amalgam utilizing various adhesive resin cements. The adhesive resin materials used in this study were Imperva Dual, Geristore, and Panavia. The scanning electron micrographs revealed that bonds were established between amalgam, adhesive resins, and dentin.
A scanning electron microscopic study of selected morphological stages of Candida albicans is presented. Stages represented are budding yeast cells, mycelial-like forms, chlamydospores, germ tube formation, and an unusual rough cell type.
A new technique for performing corneal endothelial cell autoradiography with the scanning electron microscope is presented. The scanning electron microscope is able to detect silver grains deposited over tritiated thymidine--labeled nuclei of regenerating corneal endothelium.
Using an ultrahigh-resolution scanning electron microscope (SEM), an attempt was made to directly visualize antibody molecules at antigenic sites in rat pancreas or on silicone plates. Although individual antibody molecules could not be discerned, a fluffy meshwork, probably indicating several molecules, was seen. With further improvements in specimen preparation, the high-resolution SEM promises to be an important tool in examining individual antibody-antigen sites without the need of an electron-dense label such as colloidal gold.
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Scanning electron microscopic observations of the subarachnoid space were made in dogs focussing upon the fibre components in both the normal subarachnoid space and in areas of post-haemorrhagic fibrosis. It was concluded that the fibrous tissue originates from the arachnoid membrane itself, while organized haematoma is considered to form a component of the fibrosis. Perfusion of the subarachnoid space of dogs with a solution of 0.1% Toluidine Blue was also done. This showed that cerebrospinal fluid (CSF) is carried from the subarachnoid space directly to the dural sinuses through a fine string-like structure, which is conceivably one of the collateral CSF absorptive pathways.
Observations made with a scanning electron microscope of the claw horn and underlying soft tissues of young pigs fed a normal diet supplemented with 1 mg d-biotin/kg of feed were compared with observations on a similar group receiving no additional biotin. Supplementary biotin affected the structure of the coronary epidermis; there was an increase in the density of the horn tubules in the stratum medium, the horny squames in the stratum medium were more tightly packed and the tubules were more clearly defined in the pigs receiving biotin. The width of the band of intertubular horn adjacent to the laminae was greater in the claws of control pigs.
We describe a vector scanning system to reduce charging effects during scanning electron microscope (SEM) imaging. The vector scan technique exploits the intrinsic charge decay mechanism of the specimen to improve imaging conditions. We compare SEM images obtained by conventional raster scanning versus vector scanning to demonstrate that vector scanning successfully reduces specimen-charging artifacts.
Scanning electron microscope studies of coronary bypass grafts were carried out in six routine bypass operations. Infusion of the initial crystalloid cardioplegic medium into the aortic root after aortic cross clamping was performed in every case. In two cases, pieces of aorta below and above the cross-clamped site, le, having and not having had contact with the crystalloid cardioplegic medium, were studied. The endothelial lining of the veins showed normal structure following distention with blood. Following infusion with a crystalloid cardioplegic solution, the endothelial cells had almost completely vanished and the flow surface was composed mainly of collagen fibers. The aortic samples taken from below the cross-clamp site showed similar destruction of the endothelium that was observed in vein grafts after crystalloid cardioplegic solution infusion, whereas the aortic samples taken from above the cross-clamp site disclosed normal endothelium.
Scanning electron microscopic observation of (i) leukemic cells in peripheral blood and tumor tissues of 11 cattle with bovine leukosis (adult form, n = 5; calf form, n = 2; and thymic form, n = 4) and (ii) peripheral lymphocytes from 2 cattle with persistent lymphocytosis and from 3 healthy cattle revealed morphologic differences of cell surface structures among various forms of bovine leukosis. These differences indicated an interrelationship of cell surface morphologic features between peripheral lymphocytes and tumor cells. Leukemic cells from cattle with the thymic and calf forms characteristically had a smooth surface. In cells from cattle with the adult form, the majority of abnormal cells in the peripheral blood, possessed numerous elongated microvilli on the cell surface, whereas tumor cells in the tissue were pleomorphic with a long villous, plicated surface or had stubby projections. Most of the peripheral lymphocytes from cattle with persistent lymphocytosis were characterized by a dense arrangement of elongated microvilli on the cell surface.
This is the first scanning electron microscopic demonstration of the three-dimensional architecture and detailed surface structures of the entire osseous labyrinth of the cochlea. Mouse cochleae were observed after dissolving the soft tissues with KOH and NaOCl solutions. The precise shapes, surface structures, and orientations of the primary osseous spiral lamina and secondary osseous spiral lamina in the cochlea were observed along their entire course from the hook at the base to the helicotrema at the apex. The primary osseous spiral lamina showed three half turns after the hook; the lengths of the hook and each half turn and the slope angle of the spiral were obtained. The widths of the primary and secondary spiral laminae and the spiral fissure for the basilar membrane between the free edges of the two spiral laminae were measured along the course of the cochlear duct. The surface of the lateral wall under the stria vascularis was also viewed. Scanning electron microscopy can provide more precise microanatomical data than has been previously available for the osseous cochlea, giving a better understanding of hearing mechanisms with regard to the width, support, and movement of the basilar membrane and the functions of various components of the cochlea.
This paper reports a scanning electron microscope study of the morphology of the atrioventricular (AV) valves in the mouse. The leaflet tissue of the 2 AV valves consists of a continuous veil that shows no commissures or clefts. In all instances, the chordae that arise from the papillary system merge with the free border of the leaflet tissue. No distinct terminations of chordae were observed on the ventricular face of the valves. The leaflet tissue of the right AV valve can be divided into parietal and septal components on the basis of the insertion into the ventricular wall and of the papillary system. While the septal component is similar in shape, location and tension apparatus to the septal tricuspid leaflet in man, the parietal component appears to correspond to the anterior and posterior human leaflets. This segment of the valve is served by 3 papillary muscles that arise from the septal wall. The right AV valve is not a tricuspid structure from the morphological standpoint, but appears to function as such because of the particular attachment of the papillary muscles. The leaflet tissue of the mitral valve is served by 2 papillary muscles, anterior and posterior, which consist of muscular trabeculae extending from the heart apex to the base of the valve. These muscles remain associated with the ventricular wall. The leaflet tissue attaches directly to these papillary muscles, which give rise to a very small number of slender chordae. There are thus several important differences between the AV valves of the mouse and man.(ABSTRACT TRUNCATED AT 250 WORDS)
The clinical and scanning-electron-microscope appearances of enamel defects in six patients with tuberous sclerosis are described. The pit-shaped enamel defects seem to be pathognomonic of the disease. The detection may be an important help in the early diagnosis of this complex syndrome.
The use of the Scanning Electron Microscope has made it possible through observation to study the human cervical mucus through the various stages of the ovarian cycle, as well as to describe the significant variations of the meshed woof making up the ultrastructure during the ovarian cycle. While the slackening of the woof and the dimension of the meshes are minimal at both the beginning and end of the cycle, they reach a maximum on forteenth day. In the ovulatory period, lateral expansions from the filaments are numerous. On the other hand, median and terminal thicknesses are almost inexistant during the same period : their frequency decreases during the first part of the cycle, then increases during the luteal phase. During both the preceding and following days of ovulation, one can observe numerous twistings at the level of the filaments which probably express the relaxation and then contraction of the latter. The preparatory technique as well as the method of observation used appear reliable enough to allow a comparison of the cervical mucus ultrastructure in varied physiological, pathological and experimental situations.
Scanning electron microscopy, light microscopy, and morphometric analysis were used to study the morphological changes of the otic placode and vesicle before and during invagination and closure processes. Our results reveal that the otic placode undergoes shaping between stages HH9 and HH12; during this period the rostrocaudal axis is shortened, while the lateromedial axis of the placode lengthens. The presence of long cytokinesis bridges during this period suggests that cellular displacements after mitosis may participate in the shaping of the otic placode. The shaping process appears to facilitate the approach of the otic placode to the neural tube. From stage HH12 on, the otic anlage gradually becomes a U-shaped structure with its medial portion in intimate apposition to the rhombencephalic neural tube. The coincidence in time between the beginning of intimate otic anlage-rhombencephalon contact and active invagination suggests that these two processes are related. Changes occurring at the edges of the otic vesicle until their disappearance in stage HH17 suggest that, in addition to a process of invagination, the edges of the otic anlage become bent. During closure, cells at the edges of the otic vesicle differ in apical morphology according to their topographical location: The cells between the rostral and lateral edges have elongated apices, in contrast with the polygonal shape of the cell apices in other places of the edges. In the opposite side (between the caudal and medial edges) cell death is observed. Closure of the otic vesicle conceptualized as a zipper-like model is discussed. We propose that early development of the otic anlage takes place in four stages: 1) shaping (stages HH9-11); 2) triggering of the invagination (stage HH12); 3) early invagination and lateral bending (stages HH13-15); and 4) late invagination and closure (stages HH16-17).
Scanning electron microscopy, immunocytochemistry, and single cell microspectrophotometry were employed to characterize the photoreceptors and visual pigments in the retina of the garter snake, Thamnophis sirtalis. The photoreceptor population was found to be comprised entirely of cones, of which four distinct types were identified. About 45.5% of the photoreceptors are double cones consisting of a large principal member joined near the outer segment with a much smaller accessory member. About 40% of the photoreceptors are large single cones, and about 14.5% are small single cones forming two subtypes. The outer segments of the large single cones and both the principal and accessory members of the doubles contain the same visual pigment, one with peak absorbance near 554 nm. The small single cones contain either a visual pigment with peak absorbance near 482 nm or one with peak absorbance near 360 nm. Two classes of small single cones could be distinguished also by immunocytochemistry and scanning electron microscopy. The small single cones with the 360-nm pigment provide the garter snake with selective sensitivity to light in the near ultraviolet region of the spectrum. This ultraviolet sensitivity might be important in localization of pheromone trails.
Scanning electron microscopy was used to examine factory-sharpened, dulled, and resharpened scalers. The following observations were made: 1. The factory sharpened scalers exhibited metallic extensions from the lateral surface (wire edges). 2. The machine-resharpened instruments resulted in nonfunctional wire edges from the facial surface. Honing produced an exact meeting of facial and lateral surfaces. 3. Hand sharpening, using an Arkansas stone (grit 500) against the lateral surface away from the cutting edge, effected an exact meeting of the facial and lateral surfaces and no evidence of wire edges. 4. From this study an optimum cutting edge for a scaler is characterized as having a smooth, contiguous meeting of the facial and lateral surfaces free of wire edges. If a wire edge is present, it should be functional.
Using scanning electron microscopy (SEM), differences in cell surface morphology are identifiable between normal urothelium and malignant urothelia including the presence of pleomorphic microvilli (PMV). PMV have been reported in carcinomas of the urinary bladder, and they appear early in the pathogenesis of these tumors in animal models. Preliminary studies in our laboratory and others' demonstrated similar changes in tissue and cytologic specimens from patients with bladder cancer. We observed and evaluated normal and neoplastic cells of the human bladder by SEM in a preliminary assessment of surface topography with regard to tumor growth, grade, and stage. However, while these SEM observations indicated that differences between normal and abnormal urothelia could be readily recognized, the distinction between the various types of atypical cells was not as clearly defined. Data collected so far indicates that changes in the surface topography of the exfoliated cells may possibly vary both in relation to tumor grade and stage. Based on these qualitative observations, we expanded our approach by using a computerized image analysis system directly interfaced with the SEM. The measurements which can be made include cell surface area, diameter, length, width, perimeter, orientation and number of PMV per unit area. Statistical analysis is also performed. The boundaries between cells are not recognizable by the system, making the single cells present in cytologic specimens ideal for evaluation. Uniform short microvilli are readily distinguished from PMV. Preliminary evaluation of 23 patients has distinguished specimens from malignant cases compared to patients with benign lesions.