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PubMed1984

A method for scanning electron microscopy of mitotic apparatus of cells in culture.

The mitotic apparatus of HeLa cells which had been covered with surface structures was successfully exposed for scanning electron microscopy. HeLa cells were cultured on carbon coated coverslips. After synchronization they were lysed with non-ionic detergent in a microtubule- stabilizingbuffer and embedded in styrene. Then the surface layer of the cells was sectioned away with a glass knife. Styrene was removed by treating the specimens with isoamylacetate and the cells were processed for scanning-electron microscopy. Various stages of mitotic apparatus were obtained with good preservation. Chromosomes appeared as aggregates of filamentous and granular structures. Microtubules appeared as filaments 40 nm in diameter.

Chromosomes, Human↗

PubMed1983

Time-lapse cinemicrography and scanning electron microscopy of platelet formation by megakaryocytes.

The surface architecture of megakaryocytes undergoing platelet formation in vitro has been examined by time-lapse cinemicrography and scanning electron microscopy. Fragments of mouse bone marrow were placed in culture medium and incubated at 37 degrees C. After several hours mature megakaryocytes migrated out of the marrow and some underwent shape changes so that they eventually appeared as a relatively small central body, housing the nucleus, from which emerged a number of thin processes which resembled platelet chains. Scanning electron microscopy showed that initially the megakaryocyte surface was ruffled but with development of processes it became smoother. Circumferential folds of small amplitude were found on the surface of developing constrictions which separated putative platelets. It is thought they may be associated with the mechanism of extension, but could have a role in establishing the topography of membrane components. Rupture of the chains and release of platelets was not observed; this permits the number of putative platelets formed by individual megakaryocytes to be determined. The putative platelets exhibited features common to circulating platelets when exposed to a glass surface including the development of pseudopodia and, eventually, flattening on to the surface.

Animals↗

PubMed1993

Conventional and high resolution field emission scanning electron microscopy of vertebrate cerebellar parallel fiber-Purkinje spine synapses.

Purkinje dendrite-parallel fiber spine synapses of human, teleost fishes, Rhesus monkey and mouse cerebellar cortex have been studied by means of conventional scanning electron microscopy (SEM) using ethanol-cryofracturing technique and by high resolution field emission scanning electron microscopy (HRFESEM) for studying the outer and inner surface morphology of pre- and postsynaptic endings. Transmission electron microscopy of mouse cerebellar cortex either by means of ultrathin sections and freeze-etching replicas have been complementarily used for proper identification and comparative observations. Normal teleost fishes showed short neck and neckless Purkinje spines with exhibited spread or extended postsynaptic densities. In pathological human cerebellum, the ethanol cryofracturing technique exposed the outer surface of edematous flat and invaginated Purkinje spine synapses. In fractured presynaptic endings HRFESEM showed in Rhesus monkey cerebellar cortex a homogeneous extravesicular material binded to the synaptic vesicles and joining them to the presynaptic membrane. HRFESEM partially resolved the synaptic cleft as currently observed in high magnification transmission electron microscopy. Round subunits, 25-35 nm in diameter, were observed associated to postsynaptic membrane, apparently corresponding to the localization and distribution of E face postsynaptic intramembrane particles, which suggest that such subunits correspond to the domains of neurotransmitter postsynaptic receptors.

Animals↗

PubMed1980

Scanning electron microscopy of canine pulmonary arteries and veins.

In this communication we describe (1) a method for preparing pulmonary arteries and veins for examination by scanning electron microscopy and (2) the topographic characteristics of the luminal surface of these vessels. Seven healthy adult dogs were used in this study. The pulmonary vasculature was washed free of blood by perfusion with Tyrode's solution. Blood vessels were partially fixed in situ under physiologic pressure in 3 dogs (15 mm of Hg) or 2 times physiologic pressure in 4 dogs (30 mm of Hg) by perfusion with 1% glutaraldehyde. The pulmonary artery and aorta were tied off and the lungs were removed and immersed in 1% glutaraldehyde for 4 hours for additional fixation under pressure. Blood vessels were dissected free of surrounding tissue, further fixed in 2.5% glutaraldehyde, postfixed in osmium tetroxide, dehydrated, and critical point dried. The luminal surfaces were sufficiently flat to allow visualization of most of the topographic features of the luminal surface. Even 1 missing endothelial cell wound have been obvious. Contrary to previous reports, we did not find a dense population of finger-like projections on the surface of arterial endothelium. Rather, we found a modest number of small rounded blebs. The venous endothelial sheet was similar in appearance. These observations demonstrate that scanning electron microscopy may be used to study vascular lesions in pulmonary vaessels, as well as in more accessible peripheral vessels.

Animals↗

PubMed1990

Scanning electron microscopy of vascular corrosion casts--technique and applications: updated review.

The present paper states very briefly the main steps leading to the technique of scanning electron microscopy (SEM) of vascular corrosion casts. From the terms presently used (injection method, microcorrosion cast, injection replica, vascular corrosion cast, vascular cast) the use of "vascular corrosion cast" for lymphatic and blood vessels is recommended. Specification and pretreatment (kind, volume, dosage of anticoagulants, vasoactive substances and spasmolytica used) of the animals examined are referenced as they are available from the literature. The recommendation is given to pay more attention to these parameters than done so far. The steps necessary for producing reasonable and suitable vascular corrosion casts are critically described. Special attention is paid to the physical and chemical properties of the casting media and their significance for polymerization, shrinkage, casting quality, corrosion resistance, and thermal and spatial stability. Emphasis is also focused on the advantages of cutting the vascular corrosion casts embedded in an ice block by a band saw, a self constructed multi-blade cutting device or a mini wheel-saw placed in the chamber of a cryomicrotome. From the drying methods presently used freeze-drying is stressed because of minimal specimen damage. To render casts conductive in most cases sputter-coating is sufficient. It is recommended to run the SEM with 5-10 kV since the resolution received still reveals all details the casting media presently can replicate. Further the application of scanning electron microscopy of vascular corrosion casts in fully differentiated normal tissue, in pathologic tissue as well as in developing tissues and organs is stated. Lastly possibilities and conditions are discussed under which SEM of vascular corrosion casts can serve to quantify vascular structures in order to make the technique more than pure descriptive.

Animals↗

PubMed1989

Scanning electron microscopy of dysplastic Barrett's epithelium.

Twenty-six patients with Barrett's esophagus (BE) were followed prospectively by endoscopic examination and biopsy. Two biopsies were taken from each of 4 areas of BE. One was processed for light microscopy (LM) and one for scanning electron microscopy (SEM). Those in whom dysplastic BE was demonstrated by LM were reexamined at 6-mo intervals, and the others at yearly intervals. One patient had low grade dysplasia (LGD) by LM on entry, and in 2 others, LGD was recognized on the second examination. These changes have persisted in semiannual examinations over 3, 2, and 2 yr, respectively. SEM prints were examined without knowledge of LM findings, and features that might correlate with LGD by LM were sought. SEM findings were similar to those of Zwas et al. (Gastroenterology 90:1932, 1986) in that most glandular cells had surface features unlike either gastric or intestinal cells but unique to BE. In the patient with LGD on entry, there was an aggregate of very large cells covered by short microvilli with bald patches. In the other patients with LGD, there was more variation in size and shape of cells than in nondysplastic cases.

Adult↗

PubMed1998

Origin and regional distribution of the arterial vessels of the vomeronasal organ in the sheep. A methodological investigation with scanning electron microscopy and cutting-grinding technique.

The origin and location of the arteries of the vomeronasal organ (VNO) in the sheep were studied by means of dissection, scanning electron microscopy of corrosion casts, and the cutting-grinding technique after injection with Araldite CY23-HY2967 via one of the carotid arteries. Dissection revealed that the most ventral of the three main branches of the sphenopalatine artery is responsible for the blood supply to the VNO. Scanning electron microscopy of corrosion casts revealed that the arterioles of the vomeronasal organ form a microvascular network. Cross sections of the region of the nasal cavity containing the VNO, obtained by the cutting-grinding technique, showed that the arterioles of the vomeronasal plexus are located medial and ventral to the vomeronasal duct. These results confirm the usefulness of the cutting-grinding technique as a complementary procedure in morphological studies of structures containing hard tissues.

Animals↗

PubMed2005

Fine needle aspiration cytology diagnosis of gastrointestinal stromal tumors utilizing scanning electron microscopy.

BACKGROUND: Digestive stromal neoplasms are the most frequent undifferentiated mesenchymal tumors. The outcome of these malignancies is difficult to predict and the histogenesis is still controversial. However, the frequent and specific expression of CD117 (c-kit) by these tumors could imply an origin from interstitial cells of Cajal. Our objective was to analyze the role of fine needle aspiration cytology, cell block preparation, and immunocytochemistry in the interpretation of gastrointestinal stromal tumors, and to establish scanning electron microscopy as a useful research aid for pathologic changes of the surface cells of gastrointestinal stromal tumors, not totally appreciated by light microscopy. MATERIAL AND METHODS: Twelve cases of gastrointestinal stromal tumors were included in this study, in which fine needle aspiration cytology was performed. RESULTS: On aspirated material, the tumor cells formed closely packed cohesive tissue fragments with high cellular density often in bloody background, or fascicles with parallel side-by-side arrangements of the nuclei. On cell block biopsy material, gastrointestinal stromal tumors were highly cellular spindle or epithelioid tumors with basophilic appearance. Immunocytochemically, they were CD117 positive in all twelve cases, CD34 positive in nine, weakly smooth muscle actin-positive in five, and S-100 and GFAP-negative in all cases. The scanning electron microscopy study showed a strong correlation with the cytomorphological profile. CONCLUSIONS: Gastrointestinal stromal tumors show a broad morphologic variety, but nuclear pleomorphism by cytology alone, rarely correlates with malignant potential. In the appropriate clinical and radiological setting, a confident diagnosis of gastrointestinal stromal tumors can be documented by fine needle aspiration cytology, cell block, immunocytochemical, and scanning electron microscopy results.

Biopsy, Needle↗

PubMedDate not supplied

Scanning electron microscopy of normal human peripheral blood cells.

To investigate the surface morphology of peripheral blood cells, venous blood specimens drawn from 16 normal healthy subjects were studied with scanning electron microscopy. Blood cells were fixed with 2% glutaraldehyde and stained with Riu's A and B solutions. Red blood cells, platelets and specific types of leucocytes were identified and photographed through a light microscope. The cells were then fixed with OSO4, dehydrated, dried and metal-coated. Observation with a scanning electron microscope revealed that the erythrocytes were biconcave in shape with smooth surfaces. Adhesion to one another was in rouleaux formation. The surface morphology of the neutrophils was characterized by irregular and branching ridges. Prominent pits on the cell membranes were also noted. A few microvilli, similar to those seen in lymphocytes, were distributed sporadically on the surface. Lymphocytes were much smaller in size than neutrophils. Variable amounts of short upright microvilli, which probably represented the different functional status of the cells, were observed. The monocytes possessed folding cellular processes, while the eosinophils had a villous and granular appearance. Circulating platelets existed in two forms: the native form with discoid shape and the activated form with pseudopodia. The surface was smooth. It is concluded that most peripheral blood cells can be identified by their specific topographic characters. The information thus obtained by scanning electron microscopy can facilitate the cytodiagnosis of abnormal specimens such as sputum, pleural effusion and ascites.

Blood Cells↗

PubMed1990

High resolution scanning electron microscopy of stereocilia in the cochlea of normal, postmortem, and drug-treated guinea pigs.

The morphology of hair bundles has been studied by high resolution scanning electron microscopy using a variety of fixatives, including glutaraldehyde, glutaraldehyde-picrate, glutaraldehyde-tannic acid, glutaraldehyde followed by post-fixation in osmium tetroxide, and the osmium thiocarbohydrazide technique. Critical evaluation of several metal coatings, gold, gold-palladium, and platinum has been carried out. Both the surface texture of stereocilia and their cross-links are sensitive to fixation and metal coating. We are of the opinion that glutaraldehyde gives the best general quality of fixation and preservation for all types of cross-links. We have described three major sets of cross-links: first, lateral links connecting stereocilia within the same row; second, lateral links connecting stereocilia of adjacent rows; and third, upward-pointing links, one per stereocilium, connecting the tip of each shorter stereocilium to the lateral surface of the adjacent taller stereocilium. Current physiological and anatomical evidence suggests that the lateral links couple the individual stereocilia within the hair bundle so that they function as a single mechanical unit. The upward-pointing tip links are ideally placed to respond to mechanical deformation of the hair bundle, being stretched when the stereocilia are deflected in the excitatory direction towards the tallest row and relaxed when deflected in the opposite, inhibitory direction. Postmortem morphological changes are detected within 15 minutes of cardiac arrest and become progressively more pronounced in time. These results enabled us to distinguish specific drug-induced changes which could not be attributed simply to cell death. Effects of cisplatin and kanamycin upon hair bundles are described. The work reported here is based on studies using the guinea pig cochlea. Some of the postmortem changes described have also been confirmed in human cochleas. It is stressed that many of the postmortem and drug-induced effects can only reliably be studied by high resolution scanning electron microscopy coupled with appropriate preparation procedures.

Animals↗

PubMed1987

Uncombable hair (pili trianguli et canaliculi): evidence for dominant inheritance with complete penetrance based on scanning electron microscopy.

Uncombable or spun-glass hair (pili trianguli et canaliculi) is an uncommon condition in which the hair is "unmanageable" and has a distinct appearance on scanning electron microscopy. The hair is usually grossly abnormal in infancy and childhood, but may become normal later in life. Although dominant inheritance has been observed, most cases have been sporadic. Both recessive and dominant transmission with incomplete penetrance have been suggested as modes of inheritance. We report the occurrence of this condition in a young girl, her brother, and her father. Although the proposita and her brother had characteristically uncombable hair, their father appeared normal and denied any history of hair abnormality. However, the characteristic hair morphology was observed on scanning electron microscopy in all 3 relatives, documenting dominant transmission and complete penetrance of the gene in this family.

Child, Preschool↗

PubMed1987

In vitro excystation of Giardia from humans: a scanning electron microscopy study.

The in vitro excystation of Giardia lamblia on cysts isolated from human feces was studied. After purification by sucrose gradient, cysts were incubated in a pepsin-acid solution, then placed in a modified HSP3 medium where excystation occurred within a few minutes. The excystation procedure was studied by continuous observations by light microscopy and sequential observations by scanning electron microscopy (SEM). The in vitro excystation was stopped at timed intervals during incubation by addition of a large amount of 1% glutaraldehyde. The excystation process began by the cyst wall opening at one pole. Flagella protruded rapidly, the parasite emerged progressively from the cyst envelope, posterior end first, the empty cyst collapsed and shrank. Although flagella emerging from the organism were distinguishable, the cell body had not yet shown all the morphological features of the G. lamblia trophozoite. A radical rearrangement of the organism occurred gradually: initially oval in shape, the parasite became round, then elongated, flattened, and underwent cytokinesis. The daughter trophozoites acquired their typical morphological features: the shape, the adhesive disc with the C-shaped structure distinctly visible on the ventral surface, and the definite placement of the flagella. These observations obtained on G. lamblia by SEM were comparable to those obtained with G. muris.

Giardia↗

PubMed1998

Scanning electron microscopy of central nervous system cerebrospinal-fluid-contacting surfaces: a bibliography (1963-1995).

This bibliography is compiled to assist in locating papers related to the application of scanning electron microscopy (SEM) to cerebrospinal-fluid-contacting surfaces in vertebrates. The use of SEM by neuroscientists has continued apace since the publication of the first bibliography in 1980. SEM studies now include more than 50 species of vertebrates and range from cyclostomes to humans; they encompass development from embryo to senescence and concern both normal and pathologic morphology. Although remarkable strides have been made toward a greater understanding of many aspects of the structure and function of cerebrospinal-fluid-contacting surfaces, many significant problems await the judicious application of scanning electron microscopy.

Animals↗

PubMedDate not supplied

[Effects of progesterone and nomegestrol acetate on the endometrial epithelium of the rabbit. A study with scanning electron microscopy].

Immature female rabbits were tested by the Clauberg-MacPhail technique using progesterone (P), or nomegestrol acetate (NOM), a 19-norprogesterone derivative. The endometrial surface was observed by scanning electron microscopy. Estrogen priming followed by treatment with P induced changes on the endometrial surface which were very close to those observed in menopausal women under sequential estroprogestative therapy. After treatment with NOM the aspect of endometrium surface was very close to those observed after treatment with P. This is in accordance with the pharmacological profile of the product. Scanning electron microscopy confirms the previsional value of Clauberg-MacPhail's test and provides useful complementary information for the pharmacological understanding of a new synthetic progestogen.

Animals↗

PubMed2003

Biofilm formation on intraocular lenses by a clinical strain encoding the ica locus: a scanning electron microscopy study.

PURPOSE: To determine whether the Staphylococcus epidermidis strain carries the intercellular adhesion (ica) locus, which encodes production of adhesins mediating adherence to biomaterials and to study, with scanning electron microscopy, the morphologic features of this coagulase-negative Staphylococcus strain that adheres to intraocular lenses (IOLs). METHODS: Polymerase chain reaction amplification was used to investigate whether the isolate under study (S. epidermidis clinical strain N890074) carries the ica locus. Sterile intraocular lenses (IOLs) were incubated in bacterial suspension either for 5 minutes or 1 hour. IOLs were then examined by scanning electron microscopy. RESULTS: Polymerase chain reaction amplification revealed that S. epidermidis N890074 contained the ica locus. The bacteria appeared to be anchored to the surface of the lenses by several different means-particularly by leglike appendages and a slime layer-which probably came into play step by step. CONCLUSIONS: For the first time in ophthalmology, to the authors' knowledge, photographs showing leglike appendages involved in the first phase of adhesion have been obtained. They also clearly visualize the slime layer containing the embedded bacteria. This study provides information about the nature and the genesis of these attachment processes. Adherence is known to be greater when the bacterial DNA contain the ica locus. Full knowledge of the pathogenesis of bacterial adhesion is necessary to gain a better understanding of IOL infection and endophthalmitis.

Adhesins, Bacterial↗

PubMed1993

Cast-model and scanning electron microscopy of the rat brain ventricular system.

In order to establish a good experimental model for comparative studies of the brain ventricular system in mammals, a resin-cast model and scanning electron microscopy were employed to examine the rat brain ventricular system. From the resin-cast model, we found that the gross morphology of the brain ventricular systems of rats is simpler than that of humans. From scanning electron microscopy, local variations of ependymal cells lining the rat brain ventricle were noted. Most areas of the ventricles were lined by ciliated ependymal cells arranged in regular rows, whereas in some other areas non-ciliated ependymal cells were also observed. Epiplexus cells and supraependymal cells were also encountered on the top surface of the choroid epithelium, and ependymal cells in certain area such as the pineal recess.

Animals↗

PubMed1992

Detection of neuromuscular junctions on isolated branched muscle fibers: application of nitric acid fiber digestion method for scanning electron microscopy.

Three-dimensional morphology and neuromuscular junctions of the branched muscle fibers of the rat skeletal muscles isolated from the rat were examined by application of the nitric acid digestion method for scanning electron microscopy. Treatment with fifteen percent nitric acid and a supersonic wave bath were effective in isolating the branched muscle fibers and for detecting their innervations by scanning electron microscopy. Mean numbers of total and branched fibers in the rat plantaris muscles were 11,130 +/- 314 and 32.4 +/- 4.8 (n = 12), respectively. Bifurcation of these fibers resembled either the letter X (X type) or letter Y (Y type). The Y type fibers were most frequently seen (84% of total branched fibers), and X types accounted for 14%. The remaining 2% of the fibers were subtypes of X and Y with overlapping bifurcation. These branched fibers were differentiated by their length from the bifurcated point, i.e., short, medium and long branches. Neuromuscular junctions on these branched fibers were located almost at the center of their length. The number of innervations was decided by the number of bifurcating fibers across the central part of the length.

Animals↗

PubMed1975

Scanning electron microscopy of human and rhesus monkey kidneys.

Human kidney biopsies fixed by immersion fixation and a rhesus monkey kidney fixed by vascular perfusion were critical point-dried and studied by scanning electron microscopy. The surface morphologies of the parietal and visceral epithelial cells and cells lining the uriniferous tubules are described. Many instructive views of these cells as well as some new nephronal features are presented. This study demonstrated that both scanning and transmission electron microscopy may be undertaken on the same biopsy sample. In view of these results, the possibility of using scanning electron microscopy for routine diagnosis of human biopsies is discussed.

Adult↗