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PubMedDate not supplied

Early detection of tracheal damage in chickens by scanning electron microscopy.

Fifteen-day-old chickens were inoculated with effective doses of cultured Mycoplasma gallisepticum and treated with the antibiotic tiamulin or tylosin. Scanning electron microscopy was used to detect early and late damages in the tracheal mucosa of the affected birds. Edematous changes of various degrees were demonstrated as early as day 4 postinoculation. Catarrhal changes were observed at day 10 postinoculation, and obstruction of the tracheal lumen by mucofibrinous plugs was observed at day 10 or later postinoculation. Scanning electron microscopy was useful in early detection of inflammatory changes in the trachea of apparently healthy chicks.

Animals↗

PubMed1994

Meshwork structures in bovine glomerular and tubular basement membrane as revealed by ultra-high-resolution scanning electron microscopy.

We examined the ultrastructure of the bovine glomerular basement membrane (GBM) and tubular basement membrane (TBM) using ultra-high-resolution scanning electron microscopy after conductive staining without metal coating. Purified basement membranes (BMs) were obtained by sonication and acellular BMs by detergent treatments. Purified GBMs (PGBMs) and acellular GBMs (AGBMs) showed similar meshwork structures composed of regular round or oval pores and branching strands. Pore diameters were 10.2 +/- 2.4 nm (mean +/- SD) in PGBMs and 9.8 +/- 3.1 nm in AGBMs. Purified TBMs (PTBMs) and acellular TBMs (ATBMs) exhibited heterogeneous meshwork structures in which compact meshes in the cristae were combined with coarse meshes in the invaginations on the epithelial surfaces. Pore diameters were 12.6 +/- 5.2 nm in PTBMs and 11.4 +/- 4.0 nm in ATBMs which were significantly larger than those in GBMs. The width of the strands ranged from 3 to 15 nm in all BMs. A 4 M guanidine hydrochloride extraction of the acellular BMs revealed large polygonal networks in the invaginations of the TBM and twisted strands which were considered to be type IV collagen fibrils. Ultra-high-resolution scanning electron microscopy and conductive staining were useful for the study of three-dimensional architectures of BMs and revealed heterogeneous meshwork structures in the GBM and TBM which were probably caused by a different ratio of the major components.

Animals↗

PubMed1984

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

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 polymerizations, 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 and a self constructed multi-blade cutting device offer. From the drying methods presently used freeze-drying is stressed because of minimal specimen damage. To render casts conductive in most cases sputtercoating 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. Lastly 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.

Animals↗

PubMed2002

Scanning electron microscopy of vascular corrosion casts and histologic examination of pulmonary microvasculature in dogs with dirofilariosis.

OBJECTIVE: To characterize structural changes in pulmonary vessels of dogs with dirofilariosis. ANIMALS: 8 dogs with dirofilariosis and 2 unaffected control dogs. PROCEDURE: Pulmonary artery pressure was measured in affected dogs, and dogs then were euthanatized. Scanning electron microscopy was used to examine vascular corrosion casts of pulmonary vasculature. Tissue sections of pulmonary vasculature were evaluated by use of histologic examination. RESULTS: Pulmonary artery pressure was higher in dogs with severely affected pulmonary vessels. In tissue sections, dilatation, as well as lesions in the tunica intima and proliferative lesions resulting in constriction or obstruction, were frequently observed in branches of the pulmonary artery. Numerous dilated bronchial arteries were observed around affected pulmonary arteries. Hyperplastic venous sphincters were observed in small pulmonary veins and venules. In corrosion casts, affected pulmonary lobar arteries had dilatation, pruning, abnormal tapering, constriction, and obstruction. In small arteries and arterioles, surface structures representing aneurisms and edema were seen. Bronchial arteries were well developed and extremely dilated, and they formed numerous anastomoses with pulmonary arteries at all levels, from the pulmonary trunk to peripheral vessels. Capillaries in the lungs were dilated with little structural change. Small pulmonary veins and venules had irregular annular constrictions that were caused by hyperplastic smooth muscle cells of venous sphincters. CONCLUSIONS AND CLINICAL RELEVANCE: Scanning electron microscopy of microvascular casts delineated links between the bronchial and pulmonary circulations in dogs with dirofilariosis. Results of scanning electron microscopy provided a structural explanation for the development of pulmonary circulatory disturbances and pulmonary hypertension in dogs affected by dirofilariosis.

Animals↗

PubMed1980

Scanning electron microscopy of the tracheal epithelium of calves inoculated with bovine herpesvirus 1.

Tracheal epithelium was examined by light, scanning electron and transmission electron microscopy at four, five and seven days after calves were infected intranasally with bovine herpesvirus. Similar areas were examined from uninoculated calves. Tracheal epithelial lesions were found in all inoculated calves and their degree of severity did not vary with the interval between inoculation and examination. Extensive loss of cilia leaving areas of tracheal epithelium covered by microvilli was the main feature.

Animals↗

PubMed1980

Thrombogenicity of different suture materials as revealed by scanning electron microscopy.

The thrombogenicity of five suture materials--polypropylene (Prolene), polyester (Mersilene), polyglactin 910 (Vicryl), nylon (Tthilon), and silk--was examined in vivo by scanning electron microscopy. The most blood-compatible material appeared to be Prolene. A rather satisfactory antithrombogenciity was shown by Mersilene, in comparison with which Ethilon and Vicryl provided less thromboresistance. The possible connection between the chemical changes which occur during the hydrolysis of Vicryl and its blood compatibility is discussed. Of the tested materials, silk proved to be the most thrombogenic. This study shows that the thrombogenicity of a suture material could be easily and conveniently tested in an experimental model by scanning electron microscopy, thus enabling the first choice of a suitable suture for the cardiovascular surgery, before one continues with other more sophisticated methods for the evaluation of thromboresistance.

Animals↗

PubMed1989

Scanning electron microscopy of transitory subependymal cysts in the developing midbrain of postnatal rats.

Transitory cystic cavities, associated with the subependymal region of the aqueduct in the midbrain of postnatal rats aged 1-15 days, were studied by light and scanning electron microscopy. The walls of these cysts, as observed in scanning electron microscopy, were lined by a dense feltwork of nerve fibres. Two types of cells were identified in the cysts: smaller glioblasts and larger amoeboid microglial cells. The glioblasts were characterized by a smoother cell body with radiating long processes. The amoeboid microglial cells showed blebs and pseudopodia on their surface. They either adhered to the walls or floated freely in the lumen. It is postulated that the formation of the subependymal cysts in the developing brain resulted following the cleavage or breakdown of the nervous tissue due to the expansion of the aqueduct and the brain as a whole. The amoeboid microglial cells in the cysts were probably derived from the extravasated blood monocytes in response to the physical damage ensuing during the formation of the cysts.

Animals↗

PubMed2003

[Scanning electron microscopy of eggs of Haemagogus leucocelaenus (Diptera: Culicidae)].

OBJECTIVE: To observe morphological details of the eggs of Haemagogus (Conopostegus) leucocelaenus, seen for the first time via scanning electron microscopy (SEM), with morphometric analysis of the main structures. METHODS: Eggs of Hg. leucocelaenus were obtained from females captured in the Biological Reserve of Tinguá, State of Rio de Janeiro. Some of the eggs were kept for hatching and others underwent processing for scanning electron microscopy studies. Three eggs were submitted to morphometric analysis. The material was fixed in 2.5% glutaraldehyde and postfixed in 1% osmium tetroxide, both in 0.1M, pH 7.2 sodium cacodylate buffer, then dehydrated in ethanol and dried using the critical point method. This was then set up on metallic supports, covered with gold and observed using the Jeol 5310 scanning electron microscope. Measurements were made with the aid of the Semafore analysis software coupled to the electron microscope. RESULTS: The eggs presented elliptical outlines of approximately 574 mm in length and 169 mm in width, with an egg index (l/w ratio) of 3.39 mm. The exochorion was extremely regular and had ornamentation that was usually hexagonal but sometimes pentagonal. Tubercles were observed on the chorionic cells, symmetrically arranged in relation to the longitudinal axis. Inside the cells, there were smaller, individualized tubercles, some arranged peripherally and others grouped to a greater or lesser extent in the center. The surface of the chorionic reticulum did not present rugosity. The micropylar apparatus was formed by a prominent continuous collar of 8.32 mm in thickness, with a slightly irregular surface. The micropylar disk was very evident, and was continuous with the collar. The micropyle was seen at the center of this disk, measuring 1.6 mm and with a micropylar apparatus of 27.3 mm in diameter. CONCLUSIONS: The ornamentation of the exochorion presents differences in relation to the tubercles of chorionic cells and the external chorionic reticulum between the eggs of Hg. Leucocelaenus, in comparison with the eggs of Hg. janthinomys and Hg. equinus, and also in relation to those of Aedes aegypti, Ae. albopictus and Ae. bahamensis. In various aspects, the eggs of Hg. leucocelaenus have more resemblance to those of Hg. Equinus than those of Hg. janthinomys, with greater differences presented in relation to the eggs of Hg. spegazzinii and Hg. lucifer.

Animals↗

PubMed1986

A scanning electron microscopy and histological study on the effects of the mutant eyeless (e/e) gene upon the hypothalamus in the Mexican axolotl Ambystoma mexicanum Shaw.

A scanning electron microscopy, histological, and immunochemical investigation examined the effects of the mutant gene (e) upon hypothalamic development in the Mexican axolotl. The adult eyeless mutant is sterile. Previous studies indicated that this reproductive defect was due to the mutation's effect upon the hypothalamus. The present study demonstrated the pleiotropic effects of the eyeless gene upon development of the hypothalamus. Scanning electron microscopy studies looked at the early ontogeny of the hypothalamohypophyseal system. The major morphological difference observed in the hypothalamus of normals compared to eyeless mutants was the reduced nature or complete lack of a preoptic recess in eyeless mutants. Early embryonic tissue movements also differed when normal siblings were compared to eyeless mutant axolotls. Histological examination looking for paraldehyde-fuchsin-positive secretory neurons revealed a paired nucleus preopticus in both normals and eyeless mutants, but this region lacked the emanating paraldehyde-fuchsin-positive fiber tracts in eyeless mutants. The neurohypophysis of the eyeless mutants was atrophied and contained far less paraldehyde-fuchsin-positive material when compared to normal axolotls. Immunochemical studies were done to look at the distribution of immunoreactive luteinizing-hormone-releasing hormone (ir-LHRH) in brains of eyed and eyeless mutant axolotls of different stages. This study detected deficiencies in ir-LHRH in the anterior hypothalamus of eyeless mutants. In general in the eyeless mutant axolotl, the observed anterior hypothalamic deficiencies are comparable to those observed in anurans which have had their optic vesicles removed. These observations suggest a possible utility of the eyeless mutant axolotl for studies concerned with endocrine development in the absence of hypothalamic modulation.

Ambystoma↗

PubMed1993

Scanning electron microscopy of human esophageal mucosa in patients with carcinoma of the esophagus.

Specimens taken at surgery from 15 patients with carcinoma of the esophagus were examined with scanning electron microscopy. Nine patients were treated with chemotherapy (cisplatin + 5-fluorouracil), surgery and radiotherapy; one received preoperative radiotherapy only; and the remaining five primary surgery only. Scanning electron microscopy was performed on specimens of both tumor tissue and the mucosa at least 5 cm from the tumor. In adjacent non-tumor tissue, damage due to treatment was observed in the form of changes in microridges and increased cell loss. In tumor tissue, the degree of damage was correlated to tumor response to treatment. For patients with no residual tumor after treatment, the ultrastructure was normalized with a low tumor score, while for patients with residual tumor, the score was high.

Adenocarcinoma↗

PubMed1982

[Effects of anterior chamber perfusion on the rabbit corneal endothelium: a scanning electron microscopy study (author's transl)].

The effects of intraocular irrigating solutions (TC Earle and NaCl 9%) on the rabbit corneal endothelium were evaluated utilizing scanning electron microscopy. Introcular pressure was maintained at 15 or 50 mm Hg. Rate of perfusion was between 50 microliter/min and 2 ml/min. With NaCl 9%, in eyes exposed to high pressure (50 mm Hg) for 2 hours with a rate of 50 microliter/min changes could be detected: rupture of apical junctions and minimal structural changes. Similar lesions appeared with a pressure of 15 mm Hg at a rate of ml/min. With Earle solution, no lesions were seen after 3 hours and minimal changes after 4 hours. Intraocular irrigating solution seems to be more toxic than increased intraocular pressure on the structure of endothelial cells, as seen on scanning electron microscopy. Greater sensitivity of endothelium to perfusion fluid than intraocular pressure probably explains the paradoxical appearance of corneal edema in diseased states, and suggests that endo-ocular surgical procedures require modification.

Animals↗

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↗