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At least 433 records · Page 24Linked to original sources
PubMed1990

Branching morphogenesis in the embryonic mouse submandibular gland: a scanning electron microscopic study.

The embryonic development of the salivary gland in the mouse was studied by scanning electron microscope (SEM). The submandibular morphogenesis was found to take place within its associated mesenchymal tissue. This stromal mesenchymal element has prevented us from observing three-dimensional details of the branching morphogenesis by SEM. In the present study, we applied a modified Evan's enzymatic digestion method to the embryonic submandibular gland. Consequently, we obtained important information about the morphogenetic events for the branching development of the mouse submandibular gland, demonstrating that a pit and shallow clefts are formed on the lateral aspect of the spherical end bud. This pit and cleft formation likely represents the initial morphogenetic movement of the epithelium that establishes primary branchings. Furthermore, SEM observation of the basal surface of the embryonic epithelial cells provided us views of the developmental change of cell projections probably involving epithelial-mesenchymal contacts.

Animals↗
PubMedDate not supplied

Improved depth of field in the scanning electron microscope derived from through-focus image stacks.

The depth of field limit in the scanning electron microscope (SEM) can be overcome by recording stacks of through-focus images (as in conventional and confocal optical microscopy) which are postprocessed to generate an all-in-focus image. Images are recorded under constant electron optical conditions by mechanical Z-axis movement of the sample. This gives rise to a change in magnification through the stack due to the perspective projection of the SEM image. Calculation of the necessary scaling as well as the derivation of best focus information at every patch in the image--and a contour map function derived from the selected patch depths--are incorporated in a new software package (Auto-Montage Pro). The utility of these procedures is demonstrated with examples from the study of human osteoporotic bone, where results show uncoupling of resorption and formation. The procedure can be combined with pseudo-colour coding for the direction of apparent illumination when using backscattered electron (BSE) detectors in contrasting positions.

Aged↗
PubMed1989

Cyclosporine A impairs wound healing of ureterocystoneostomy in rats. Scanning electron microscopic examination.

The effect of cyclosporine A (CsA), an immunosuppressive agent used in transplantation, on wound healing following microsurgical neoimplantation of a ureter in the bladder of 63 SIV ZUR rats was examined morphologically using the light and scanning electron microscopes and functionally by radiography. Following ureterocystoneostomy (UCN) on the right side, the animals in Group I (control group) received 1.0 ml CsA solvent (0.1 g ethanol and 0.3 g intralipid) per day. Group II received 12.5 mg/kg/day CsA and Group III 17.5 mg/kg/day CsA. All drugs were administered i.p. A third of the animals in each group were reoperated 7, 14 or 28 days after UCN. At these time intervals, there were no radiologically demonstrable differences in the operated side. Examination under the scanning electron microscope indicated delayed restitution of epithelium in the bladder for rats which had received CsA as compared to the control group. In the area of the UCN, CsA caused dose-independent retardation of the regenerative hyperplasia associated with wound healing (Group I: max. 7 days after UCN: Group II and Group III, max. 14 days after UCN). Hyperplastic areas had ropy microridges and uniform short microvilli. Where the hyperplasia exhibited nodular and papillary formation, also histologically more evident under CsA, occasional epithelial cells had pleomorphic microvilli on their luminal surface. Unlike other known premalignant changes of this kind, the frequent occurrence of pleomorphic microvilli under CsA was reversible. In general, CsA led to dose-unrelated protraction of UCN wound healing with no lasting functional disturbance in rats.

Animals↗
PubMed1982

Scanning electron microscopic study of age-related surface changes in rat femoral head articular cartilage.

The articular surface of the femoral heads of young (5 month-old) and old (21 month-old) female rats were examined with the use of the scanning electron microscope using an especially sensitive preparative technique in which the femoral heads were fixed in a glutaraldehyde-paraformaldehyde fixative, post-fixed in OsO4, dehydrated in ethanol and critical point dried. The articular surfaces of the young group were relatively smooth with only small ridges, which may represent superficial collagen fibrils embedded in a proteoglycan matrix. The old group's articular surfaces differed in 2 ways from the surfaces obtained from the young group. First, circumscribed depressions (roughly 20-25 micrometers in diameter) were found, which may represent the empty lacunae of superficial-layer chondrocytes. Secondly, the articular surface was 'roughened', apparently by numerous exposed collagen fibrils that may have been exposed as a result of a loss of superficial proteoglycans. It is concluded that our methodology of tissue preparations for observation with the scanning electron microscope is a sensitive and practical technique that could be useful for characterizing early morphological manifestations of articular cartilage degenerative changes.

Aging↗
PubMed1988

Ulcerative colitis in protracted remission. A quantitative scanning electron microscopic study.

Colonoscopic biopsies from 32 patients were studied at the ultrastructural level using a scanning electron microscope (SEM). Sixteen of the 32 patients had a previous diagnosis of total ulcerative colitis (UCR greater than 10 years) in protracted remission. The colonic mucosa was normal at endoscopic and histologic examinations (UCRN). The remaining 16 patients had normal colonic mucosa, but had an adenoma or an adenocarcinoma elsewhere in the colon. Several ultrastructural parameters were investigated, such as the number of crypts per area, the distance between the crypts, the outline of mucosal units, the number of mucous cells, the outline of absorptive cells, and the number of villi per area. Quantitative determinations of SEM structures (including measurements with an interactive digital image analyzer system; MOP 30, Zeiss Contron) were made. The results showed no significant differences between the various parameters (except for the number of crypts per area) between patients with UCRN and controls. The possibility of a total (or quasi-total) restitutio ad integrum of the colonic mucosa in certain patients with UCR is discussed. An international policy regarding the colonoscopic surveillance of patients with UCRN should be elaborated. It is suggested that the time interval between control colonoscopic biopsies in patients with UCRN should be increased substantially.

Adenocarcinoma↗
PubMed1990

Scanning electron microscopic observations of microcanals and continuous zones of interglobular dentin in human deciduous incisal dentin.

Scanning electron microscopic (SEM) observation of the coronal dentin of deciduous incisors revealed microcanals and continuous zones of interglobular dentin (CID) in the labio-lingual central portion of dentin beneath the incisal edge. The microcanals, which were clearly larger than dentinal tubules, extended from the incisal edge to the vicinity of the pulp cavity. They were located essentially in the labio-lingual central portion of the dentin and were arranged linearly in the mesio-distal direction. Inside the microcanals, collagen fiber bundles were arranged almost in parallel with the canal long axis: spherical bodies 1.0-2.5 microns in size made up of assemblies of regular parallelpipedal crystals and granulated crystals were also seen. In some instances, bacteria had invaded incisal dentin that had been exposed by attrition. The CID were made up of interglobular dentin aligned with the long axis of the tooth. As was true in the case of the microcanals, several zones were arranged irregularly in the mesio-distal direction, generally in the labio-lingual central portion of the coronal dentin. The CID were confined to about half the width of the incisal edge dentin on the incisal edge side and did not appear in the vicinity of the pulp cavity. Within the interglobular dentin itself, which was surrounded by calcospherites, were longitudinal collagen fibers connected with dentinal tubule walls inside calcified dentin and collagen bundles forming a network with those fibers. Spherical bodies 1.0-1.5 microns in size were observed attached to the surfaces of the bundles or distributed among these fibers. In some instances, the microcanals penetrated the CID.

Child↗
PubMed1992

Observation of atomic steps on single crystal surfaces by a commercial scanning electron microscope.

Atomic steps on (111) and (100) crystal surfaces of Pt were observed using a commercial scanning electron microscope (SEM) in secondary electron mode. By comparing the SEM images and those by reflection electron microscopy (REM), the observed contrast was confirmed to be that from atomic steps on crystal surfaces. The contrast mechanism is briefly discussed. One application of this imaging technique is also shown.

Gold↗
PubMed1979

Scanning electron microscope surface morphometry of type II alveolar lung cell response to urethane in strain A mice.

Quantitative scanning electron microscope (SEM) examination of the time course of type II cell hyperplasia in mice exposed to a single i.p. injection of urethane is presented. Counts of type II cells from random alveoli suggest that, compared to controls, a significant depression in type II cell numbers occurs during the first week, followed by a doubling in the next 3 to 4 week period. This supports conclusions of earlier studies done with thin sections and light morphometric techniques. The use of a SEM as the morphometric tool is statistically more efficient, however, since initial sample preparation is easier, samples are larger in area, resolution is higher and, most importantly, the amount of surface area available for examination is many times greater than that presented by light microscope examination of cross sections with equivalent magnification.

Animals↗
PubMed1986

[Intravascular papillary endothelial hyperplasia of the breast--report of a case with scanning electron microscopic observations].

A 65-year-old woman noticed a left breast mass and underwent excisional biopsy. The excised mass measured 1.7 cm in diameter. Histologically, the tumor-like mass revealed irregular vascular channels with occasional thrombi and many papillary projections of fibrous stalks lined with a layer of flat endothelial cells. A small cavernous hemangioma was present adjacent to the lesion. Scanning electron microscopic observation revealed disorderly oriented thin and thick cords forming branches and meshworks in the lumina. The luminal wall and cords were covered with flat endothelial cells. Light and scanning electron microscopic differences between intravascular papillary endothelial hyperplasia and angiosarcoma are discussed.

Breast↗
PubMed2000

The effects of space charge on contrast in images obtained using the environmental scanning electron microscope

We present experimental evidence for the existence of a space charge in the environmental scanning electron microscope. Space charge formation is attributed to differences in the mobilities of negative and positive charge carriers in the imaging gas. A model is proposed for the behavior of space charge during image acquisition. The effects of space charge on images acquired using the gaseous secondary electron detector, ion current, and backscattered electron signals are interpreted using the proposed model.

Journal Article↗
PubMed1984

Spleen alterations in hairy cell leukemia: a scanning electron microscopic study.

In Hairy Cell Leukemia (HCL) peripheral blood and bone marrow cells show under the scanning electron microscope (SEM) a characteristic surface with numerous ruffles and microvilli. The spleen of a patient affected by HCL was studied by SEM after fresh sectioning and routine preparation. Cells with the typical "hairy" surface were observed infiltrating the red pulp, altering the normal reticular meshwork and causing red blood cell distortion. In the sinuses, hairy cells adhered to the endothelial cells causing sinus dilatation and destruction. Aggregates of hairy cells delimiting pooled erythrocytes were also observed and may represent the "pseudosinuses" described in previous light and transmission electron microscopic studies. These preliminary findings may explain the condition of hypersplenism which characterizes HCL. In addition, SEM is proposed as a rapid and simple method to identify HCL spleen involvement.

Bone Marrow Cells↗
PubMed1990

[Experimental studies in the healing process of the rats tongue after Nd:YAG contact laser irradiation. Scanning electron microscopic observation].

The Nd:YAG laser is useful in clinical oral surgery because of its superior hemostatic and coagulating effects. The purpose of this study was to examine the healing process of the tongue wounds caused by the Nd:YAG contact laser. A scanning electron microscope (SEM) was used, focusing mainly on the papillae filiformes of the tongue, and the results were compared with the pathological findings. The laser's effect on the microcirculatory network and the healing process were observed using the injection replica scanning electron microscope method. One hundred and eighty nine male Wistar rats were used in the experiment. Irradiation condition were 3, 6, 9 and 12-W for 1.0 second. The rats were sacrificed immediately after irradiation and on the 1st, 4th, 7th, 10th, 14th, 21st, 28th and 56th days after irradiation. The results were as follows. Pathological observations; Immediately after irradiation, the 3-W wound was observed below the lamina propria. The 6-W and 9-W wounds were observed from the upper musculi transversus linguae to the near center. The 12-W wound was observed to the center of the musculi transversus linguae. SEM observations; In the case of the 3-W wound, on the 7th day, normal epithelization was largely complete and there was a mucosal bulge which appeared to be regenerating papillae filiformes at the edge of the wound. On the 28th day, regenerated papillae filiformes were observed over the entire surface of the wound. The similar healing process was observed for the 6, 9 and 12-W wounds. However, in the cases of the 6-W and 9-W wounds the regenerated papillae filiformes were morphologically different from the original ones. In the case of the 12-W wound, on the 56th day regenerated papillae filiformes were observed around the edge of the wound but not in the center. Injection replica SEM observations; Concerning the effect of contact laser irradiation (6-W) on the tongue's microcirculatory network, the blood vessels at the edge of the wound were cut straight off, which suggested that they had been cauterized. Observations of the network during the healing of the wound showed that capillary loops had been restored and were related to the papillae filiformes.

Animals↗
PubMed1975

Hemocyanin - antibody labeling of phodopsin in mouse retina for a scanning electron microscope study.

To reveal the presence of rhodopsin on the surface of the mouse retina, a scanning electron microscope study of the immunolabeling of rhodopsin was attempted. The glutaraldehyde-fixed mouse retina was treated first with rabbit antibodies specific against bovine rhodopsin and then with hemocyanin-labeled goat antibodies specific against rabbit antibody. The distribution of hemocyanin label on mouse retina and the technique used for labeling are discussed.

Animals↗
PubMed1980

Scanning electron microscope visualization of the mammary gland secretory unit and of myoepithelial cells.

Mammary gland pieces from lactating mice were incubated for various times up to 4 h in collagenase and then additionally for up to 1.5 h in a mixture of collagenase and hyaluronidase. Tissue then was fixed and prepared for scanning electron microscope viewing. Monitoring of time of enzymic hydrolysis allowed visualization of connective tissue sheets, secretory lobules, blood vessels, alveoli encased in and devoid of basement membrane, secretory epithelia, alveolar milk ducts, and myoepithelial cells. Scanning electron microscope viewing of alveoli in cross section showed good internal micro-anatomy including a valve-like arrangement of secretory epithelia at the point of milk duct attachment. Morphology of myoepithelial cells and their relationship to secretory cells and to each other was presented. There was no evidence that myoepithelial cells were interconnected continuously throughout the tissue, but they interlaced over an alveolus; thus, the concept of a limited physiological syncytium was advanced.

Animals↗
PubMed1985

Mammalian fertilization as seen with the scanning electron microscope.

For several years we have been looking at mammalian gametes and their interactions with the scanning electron microscope (SEM). Examining the images produced by the SEM has given us a three-dimensional view of sperm, eggs, and egg investments. We are particularly impressed with the structural variation among gametes of different mammalian species. In this short report we examine the structure of mammalian spermatozoa, eggs, zonae pellucidae, and cumuli. Our observations and those of others have led us to believe that variation in gamete structure and function may have evolved as a mechanism for reproductive isolation of mammalian species.

Animals↗