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Results for “scanning electron microscope”

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At least 937 records · Page 52Linked to original sources

PubMed1978

[The structure of the round window membrane studied by thin section.- freeze-fracture- and scanning electron microscopic technique (author's transl)].

In thin sections of the round window membrane of chinchilla there were found tight junctions between the cells of the outer and of the inner cell layer as well. Their structure was demonstrated in freeze-fracture replica, and in the scanning electron microscope both faces of the membrane appeared uninterrupted. The tight junctions between the mucosal cells constantly became visible and are considered impermeable; however, the junctions connecting the mesothelial cells, which face the perilymph, demonstrated high susceptibility against differences in preparation and were structurally different.

Animals↗

PubMed1986

Histopathologic and scanning electron microscopic study of one type of intraocular lens.

We performed clinicopathologic analyses of 28 explanted anterior chamber intraocular lenses (Stableflex). Two factors strongly indicated that this lens can be difficult to remove: (1) the clinical histories obtained from the explanting surgeons who, with few exceptions, stated that removal was extremely difficult; and (2) our scanning electron microscopic findings, which documented extensive tissue encapsulation around loops as well as multiple sites of loop severance required at the time of lens removal. The general efficacy of this intraocular lens compared with other anterior chamber lenses was not addressed in this study.

Humans↗

PubMed1984

Endothelialization following end-to-end and end-in-end (sleeve) microarterial anastomoses. A scanning electron microscopic study.

Eighteen microvascular end-to-end and eighteen end-in-end anastomoses were performed on the central arteries (diameters 0.8-1.2 mm) of rabbit ears. Specimens taken after intervals of 1-2 hours and 3, 7, 14, 30 and 90 days were studied using a scanning electron microscope. At 1-2 hours platelets and to a minor extent erythrocytes and fibrin had accumulated in defects between the vessel ends on sutures and at the suture holes of all end-to-end anastomoses. This had also occurred at the distal end of the telescoped segment in all end-in-end anastomoses. At 3 days endothelial desquamation at anastomotic sites and clamp sites was found in both end-to-end and end-in-end anastomoses. The exposed subendothelial surface was covered with a carpet of platelets, and frequently numerous leucocytes were found. Between 3 and 7 days, new endothelial cells appeared at the junction between the vessels in end-to-end anastomoses and in all areas damaged by vascular clamps. At the ends of the sleeved segments reendothelialization was observed over platelet aggregates. Between 7 and 14 days neo-endothelialization seemed to be virtually completed in both types of anastomosis. In the vicinity of the anastomoses, the appearance of the new endothelium was frequently abnormal with irregularly formed cells. Characteristic clefts and holes were seen between these abnormal (pleomorphic) endothelial cells. Histological findings from the same vessel specimens show that areas with abnormal endothelialization correspond to segments with intimal hyperplasia. Such areas were found in specimens throughout the entire period studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1988

Human macrophages from skin: II. Histochemical, cytochemical and scanning electron microscopical identification.

The recent development of a simple not invasive method for isolating macrophages from the skin of normal subjects has also provided a unique opportunity for morphological studies. Human macrophages isolated from skin blisters (n = 34) (Michna 1988) are identified as substratum using the proof of unspecific esterase with alpha-naphthyl-butyrate. The typical morphological features of human macrophages are demonstrated in a transmission and scanning electron microscopic study. In a cytochemical part the lysosomal potenties of these human macrophages are displayed.

Acid Phosphatase↗

PubMed1989

Scanning electron microscopic studies on the red pulp of the mink spleen.

In order to obtain three-dimensional information on the fine architecture of the red pulp of the mink spleen, especially the circulation pattern in the red pulp, perfusion-fixed and freeze-cracked specimens were examined with a scanning electron microscope. A latticework was formed by elongated endothelial cells (rod cells) with side processes and the spongy reticular tissue. The outer surface of the sinus was covered with fine processes of reticular cells. Numerous sheathed arteries were found in the splenic cord. The sheath was composed of a few layers of flat reticular cells. The arterial capillaries of the red pulp opened directly into the cordal space. No evidence could be detected to prove or suggest any direct continuity between arterial capillaries and splenic sinuses. These results strongly support the concept of "open circulation", at least in the red pulp of the mink spleen, with the possibility of a "functionally closed circulation" under some physiological conditions.

Animals↗

PubMed2000

Scanning electron microscopic analysis of arterial line filters used in cardiopulmonary bypass.

The clinical value of arterial line filters is still a controversial issue. Proponents of arterial line filtration argue that filters remove particulate matter and undissolved gas from circulation while opponents argue the absence of conclusive clinical data. We conducted scanning electron microscope (SEM) studies of arterial line filters used clinically in the cardiopulmonary bypass circuits during adult cardiac surgery and analyzed the types and characteristics of materials entrapped in the arterial line filters. Twelve arterial line filters were obtained during routine hypothermic cardiopulmonary bypass in 12 adult cardiac patients. The arterial line filter was a screen type with a pore size of 40 microm (Baxter Health Care Corporation, Bentley Division, Irvine, CA, U.S.A. ). After opening the housing, the woven polyester strands were examined with SEM. All segments examined (120 segments, each 2.5 x 2. 5 cm) contained no embolic particles larger in their cross-sectional area than the pore size of the filter (40 microm). The origins of embolic particulates were mostly from environmental foreign bodies. This may suggest a possible need for more aggressive filtration of smaller particulates than is generally carried out at the present time.

Adult↗

PubMed1982

Chemical modification of hemoglobin in intact whole cells: morphological studies by scanning electron microscope.

1. Whole blood was incubated in physiological conditions with a variety of modifiers capable of modifying hemoglobin. Some of these compounds have been considered as therapeutic agents for certain hemoglobinopathies such as sickle-cell disease. 2. The extent of modification on hemoglobin was estimated by electrophoresis and the red-cell morphology by scanning electron microscope. 3. Results indicated that carbamyl phosphate, aspirin and glutaryl-salicylamide had no observable effect, whereas cross-linkers in general produced drastic changes in red-cell morphology. 4. Dibromoaspirin, a very effective acetylating agent, produced abnormalities even in concentrations as low as 1 mM.

Anemia, Sickle Cell↗

PubMed1980

Scanning electron microscopical study of tracheal vascularization in guinea pig.

In view of a considerable increase of the tracheal injuries brought about by intubation, further detailed information on microcirculation of the trachea is needed. For this purpose, the normal microvascularization of the guinea pig trachea was investigated in microcorrosion casts viewed in a scanning electron microscope. The trachea is supplied by longitudinal vascular bundles running at both sides of the organ, including both longitudinal tracheoesophageal arteries and veins. They are the source of a segmental vascularization of the trachea. Due to numerous arteriovenous anastomoses and anastomoses occurring within respective arterious and venous vascular systems, a constant blood flow within submucous capillary plexus and the tracheal wall is provided. A characteristic feature of tracheal vascularization is a very rich, dense network of veins, which form well-developed plexuses, particularly in tracheal segments covered by skeletal cartilages.

Animals↗

PubMed2000

Advantages of stereo imaging of metallic surfaces with low voltage backscattered electrons in a field emission scanning electron microscope

High emission current backscattered electron (HC-BSE) stereo imaging at low accelerating voltages (</= 5 keV) using a field emission scanning electron microscope was used to display surface structure detail. Samples of titanium with high degrees of surface roughness, for potential medical implant applications, were imaged using the HC-BSE technique at two stage tilts of + 3 degrees and - 3 degrees out of the initial position. A digital stereo image was produced and qualitative height, depth and orientation information on the surface structures was observed. HC-BSE and secondary electron (SE) images were collected over a range of accelerating voltages. The low voltage SE and HC-BSE stereo images exhibited enhanced surface detail and contrast in comparison to high voltage (> 10 keV) BSE or SE stereo images. The low voltage HC-BSE stereo images displayed similar surface detail to the low voltage SE images, although they showed more contrast and directional sensitivity on surface structures. At or below 5 keV, only structures a very short distance into the metallic surface were observed. At higher accelerating voltages a greater appearance of depth could be seen but there was less information on the fine surface detail and its angular orientation. The combined technique of HC-BSE imaging and stereo imaging should be useful for detailed studies on material surfaces and for biological samples with greater contrast and directional sensitivity than can be obtained with current SE or BSE detection modes.

Journal Article↗

PubMedDate not supplied

Peculiar characteristics of the insertion area of the masseter muscle in rats. Scanning electron microscopic study.

The structure of the bone surface of the insertion area of the masseter muscle was studied in 20 albinus Wistar rats. Specimens were fixed in a modified Karnovsky solution and treated according to the technique described by LESTER et alii and examined in a JEOL scanning electron microscope, JSM-P15. The results showed that the insertion area of the masseter muscle of rats presents a smooth surface covered by thick layers of calcified collagen fibers. In adjacent areas of the lower edge of the mandibular angle an irregular surface with bone reabsorption and foraminae was observed. The vascular foraminae measure from 30 to 50 microns in diameter and the distance between them ranges from 200 to 460 microns. Osteocyte lacunae were seen at the surface and their measures range from 18 to 25 microns in diameter, which were surrounded by collagen fiber bundles of longitudinal disposition.

Animals↗

PubMed1985

Evaluation of danazol influence upon the uterus using scanning electron microscopic morphometric and biochemical analyses.

A study using a Sprague-Dawley rat model was designed to correlate morphologic and intracellular steroid receptor alteration with danazol therapy. One uterine horn was removed for cytoplasmic estrogen receptor analysis following four to eight days of danazol therapy. This was followed by intra-aortic injection of buffered phosphate solution and 3 per cent glutaraldehyde. The remaining uterine horn was removed for scanning electron microscopic and morphometric analysis of light microscopic changes. After four days of treatment, there was an increase in the nuclear to cytoplasmic ratio compared with that of the control tissue. Vaginal smears on the eighth day of danazol exposure indicated that the rats had entered a noncycling estrus state, and there was a significant increase in the estrogen-specific binding capacity of the endometrial cells. Scanning electron microscopy showed a distinct decrease in endometrial folds, microvilli and glandular openings, which suggests a decline in secretory activity in the danazol-treated group. Thus, danazol induced measurable changes in the estrogen binding capacity of endometrial cells, and these changes correlated with certain morphologic alterations in the endometrial lining.

Analysis of Variance↗

PubMed1998

Scanning electron microscope study of Mirophthirus liae (Anoplura: Mirophthiridae) and confirmation of the family status of the Mirophthiridae (Phthiraptera: Anoplura).

The family Mirophthiridae was erected in 1980 to accommodate the monotypic sucking louse Mirophthirus liae Chin, an ectoparsite of the Chinese pygmy dormouse, Typhlomys cinereus. Some systematists did not accept this taxonomic designation and instead placed M. liae in the family Polyplacidae. The scanning electron microscope study described here provides further diagnosis of M. liae and, based on the unique morphological characteristics of this louse, it is returned to the monotypic family Mirophthiridae. A diagnosis of the family Mirophthiridae is provided.

Animals↗

PubMed1997

[Scanning electron microscopic changes of maxillary sinus mucosa before and after functional endoscopic sinus surgery].

We attempted to evaluate postoperative maxillary sinus mucosal changes in 20 maxillary sinuses of 16 patients who underwent functional endoscopic sinus surgery (FESS). Ciliated area of the maxillary sinus mucosa and ostium of maxillary sinus were quantitatively observed by scanning electron microscope and image analysis before and after FESS. In the present study, the number of preoperative ciliated cells of maxillary sinus mucosa and ostium was significantly reduced, goblet cells and microvillous cells were increased, and squamous cell metaplasia observed in part of the maxillary sinuses. Many damaged ciliated cells tend to recover and ciliated area significantly increased at 6-12 months after the surgery. The results showed that the damaged ciliated epithelium could return to normal by the improvement of ventilation and drainage of the maxillary sinus following FESS.

Adolescent↗

PubMed1998

Fiber numbers per unit weight of JFM standard reference samples determined with a scanning electron microscope. Japan Fibrous Material.

A standard reference 10 sample-set of fibrous minerals were prepared by the Japan Fibrous Material Research Association (JFMRA) under the name of JMF standard reference samples. In this paper, the fiber number per unit weight of JFM standard reference samples was determined with a scanning electron microscope. Fiber numbers per unit weight (f/microgram) and standard deviations observed in this experiment were as follows: glass wool (GW1) 7.0 +/- 0.1 x 10(2), rock wool (RW1) 1.7 +/- 0.2 x 10(3), micro glass fiber (MG1) 6.5 +/- 0.4 x 10(4), refractory ceramic fibers; (RF1) 8.8 +/- 0.7 x 10(3), (RF2) 8.7 +/- 0.8 x 10(3), mullite fibers (RF3) 3.5 +/- 0.7 x 10(3), potassium titanate whisker (PT1) 5.9 +/- 0.3 x 10(5), silicon carbide whisker (SC1) 4.1 +/- 0.4 x 10(5), titanium oxide whisker (rutile) (TO1) 6.4 +/- 0.6 x 10(5), and wollastonite (WO1) 2.4 +/- 0.1 x 10(4). Fiber numbers per unit weight would change in proportion to the cube or cube root of the fiber size if the fibers have the same density and the same aspect ratio. JFM standard reference samples should be used taking into consideration the difference in fiber number per unit weight when users conduct in vitro and/or in vivo (injection) biological experiments using these samples.

Humans↗

PubMedDate not supplied

Allergic nasal polyps under scanning electron microscope.

The study material consisted of 18 patients (10 men, 8 women, aged 26-66 years), suffering from recurrent nasal polyps and bronchial asthma. Nine patients manifested intolerance to aspirin and non-steroid anti-inflammatory drugs (NSAIDs). The polyps removed during one of polypectomies were analysed with the help of scanning electron microscope (SEM) in order to evaluate the morphology of their surface. All the specimens displayed the increase in areas of cilium-free epithelium, covered with short microvilli and squamous epithelial cells. The arrangement of these changes was irregular and they were more pronounced in patients with intolerance to aspirin and NSAIDs. Apart from this, there were no other differences which would allow to differentiate in SEM investigation between polyps derived from patients with and without tolerance to NSAIDs.

Adult↗

PubMed1983

Scanning electron microscopic evaluation of variably angled end-to-side microvascular anastomoses.

A comparison of right-angled and opposing oblique-angled end-to-side microvascular anastomoses with both patent and occluded recipient vessels was performed in rats. Patency rates after 3 weeks were comparable in all types of anastomoses (average, 92%). However, scanning electron microscopic evaluation revealed a variety of both nonspecific (pits, craters, folds, etc.) and angle-dependent (mounds, erosions, bridges, etc.) endothelial alterations. It is concluded that, in proximally patent recipient vessels, the functional integrity of the anastomosis is not related to the grafting angle; however, in proximally occluded recipient vessels, retrograde-directed oblique angles may lead to progressive embarrassment of anastomotic function.

Animals↗

PubMed1991

Scanning electron microscopic study of three glioblastoma multiforme (GBM) cell lines of the Chinese brain in vitro and in vivo.

Three permanent glioblastoma multiforme (GBM) cell lines have been successfully established and characterized from the Chinese brain GBM tumors. The tumorigenicity in the athymic nude mice with multiple pulmonary metastases are observed. The scanning electron microscopic examinations reveal numerous surface microvilli and blebs of various size on the primary GBM tumors, the cultured tumor cells in vitro and the xenografted tumor cells in the nude mice in vivo. The distinct ultrastructural features of stellate cultured cells with astrocytic-differentiation after db-cAMP treatment of 96 hours show many intermittent dilations (pseudopods) along the long cytoplasmic processes. The intermittent dilatations and growth cones also express strongly positive immunostaining for GFAP. The growth inhibition of db-cAMP treated, cultured in vitro tumor cells is also observed. We are convinced that the continuous, established cell lines and tumorigenicity in the athymic nude mice may constitute the best reliable in vitro and in vivo systems for the investigation of human brain GBM.

Animals↗

PubMed1984

Calcium deposition on the maternal surface of the human placenta: a scanning electron microscopic study.

To explore the role of calcium in the materno-foetal relationship we decided to study the surface ultrastructure of the human placenta. Fresh pieces of tissues were obtained from central and peripheral parts of the maternal surface of human full-term placentas, processed and then examined with the Scanning Electron Microscope. Calcium depositions could only be seen at higher magnifications in forms of flecks, plaques, and concretions. They were frequently found in firm association with the tips of microvilli projecting from the apical parts of the syncytiotrophoblasts, which led to the clumping of those tips. Regional variations in the distribution of calcium deposits were apparent. Our findings indicate that placental calcification is a continual process occurring simultaneously in various parts of the placenta to varying degrees. Moreover, it seems possible that the process of placental calcification is of clinical and pathological significance bearing relationship to both maternal and foetal conditions.

Calcium↗