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PubMed1983

[Vascularization of the cervical trachea and its clinical relevance. A scanning electron microscopy study on corrosion casts].

The angioarchitecture of the cervical trachea of the rat as a model was studied using scanning electron microscopy of vascular corrosion casts. Four different types of vascular pattern are described. 1. Supplying and draining vessels of the first order (Superior and inferior thyroid arteries, and inferior thyroid veins) situated within the peritracheal tissue at the lateral sides of the trachea. 2. The vessels arising from them, which have a horizontal course and lie within the intercartilaginous membrane (vessels of the second order). 3. The vessels of the third order branching from those of the second order, perforating the intercartilaginous membrane and again running vertically within the tracheal mucosa. 4. Vessels of the fourth order forming the capillary plexus of the tracheal mucosa, consisting of irregular (pars fibrocartilaginea) or rectangular (pars membranacea) meshes. The clinical relevance of the vascular patterns of the trachea is discussed in respect to ischemic tracheal lesions.

Animals↗

PubMed1984

Scanning electron microscopy of urinary calculi--some peculiarities.

Within the scope of the investigation of more than 1,500 urinary calculi by scanning electron microscopy (SEM), some peculiarities arose concerning secondary phase transitions and morphology of some of the crystalline phases present. There is evidence for a phase transition from Ca-oxalate dihydrate to the monohydrate form in oxalate rich stones. This is characterized by a transitional zone, in which often relatively large monocrystals of newly formed whewellite are found, sticking within weddellite crystals with typical dissolution signs. We conclude that the phase transformation is regulated by dissolution and recrystallization. In mixed uric acid / uric acid dihydrate stones, occasionally parallel growth of apparently two different kinds of crystals upon each other can be observed, which possibly are uric acid crystals grown epitaxially on uric acid dihydrate. A few nearly pure whewellite stones with little Ca-phosphate at the central core show tubules which obviously had been part of a calcified renal papilla and so had been acting as a nidus for stone formation. Bacterial footprints as well as calcified bacteria have only been found in apatite containing stones of patients with urinary tract infections by Escherichia coli. These bacteria are likely responsible for the origin of these footprints.

Calcinosis↗

PubMed1984

[Fate of artificial lenses: a scanning electron microscopy study].

Thirty one intraocular lenses removed from human eyes 2 months to 30 years after implantation were examined by scanning electron microscopy. Binkhorst 4 loop lenses (12) and 2 loop lenses (6), and Choyce lenses (6) were the most prevalent styles examined. Most of the lenses produced before 1978 were found to have manufacturing defects (mold disalignment, unfinished gate areas, etc.). More recent lenses showed an improvement in the quality of the surface. The lenticular, nonimpinging portion of the lenses made with polymethylmethacrylate did not demonstrate signs of degradation. However the holes in the edges of the lenses were rough and poorly finished with obvious irregularities. On the other hand, the lens foot of a Choyce lens revealed severe unusual abnormalities: the plastic surface changes may be consistent with degradation. Examination of explanted iris clip lenses showed degradation of the polypropylene loops in two cases: the loops were found to have fractured surfaces.

Corneal Diseases↗

PubMed1982

Scanning electron microscopy of the developing chick tegmentum vasculosum.

The developing tegmentum vasculosum in the chick cochlea was analyzed by means of scanning electron microscopy. Chick embryos representative of Hamilton and Hamburger stages 35, 37, 41 and 45 were examined in order to study the morphogenesis of the "lamellae" (Knowlton, 1967), or folds, of the tegmentum vasculosum and the differentiation of the light and dark cell luminal surfaces. At stage 35 low folds are distinguishable in the proximal segment of the cochlear duct only. In subsequent stages a complex series of lamellae develop throughout the entire tegmentum vasculosum in conjunction with a developing capillary network. Dark cell luminal surfaces are clearly distinguishable from the adjacent light cell surfaces by stage 37. Stages 41 and 45 show a progressive increase in dark cell surface area as well as a considerable increase in the number and size (height and diameter) of surface microvilli. The avian tegmentum vasculosum is thought to be the functional equivalent of the stria vascularis in mammals. Analysis of the morphogenesis of the tegmentum vasculosum is vital to a thorough understanding of its functional relationships with the maturing endolymphatic fluid ionic composition and endocochlear potential.

Animals↗

PubMed1982

Scanning electron microscopy of rat liver hyperplastic nodules induced by diethylnitrosamine.

Rat liver hyperplastic nodules induced by diethylnitrosamine (DEN) were observed by scanning electron microscopy (SEM). Liver hyperplastic nodules were made according to the methods of Solt and Farber. Hyperplastic nodules appeared 4 weeks after DEN administration and these early hyperplastic nodules continued growing and became eosinophilic hyperplastic nodules 5 to 6 weeks after DEN administration. SEM revealed that hyperplastic nodules were composed of enlarged hepatocytes which formed two-cell-thick plates. Intercellular surfaces of hepatocytes were covered with numerous microvilli. Dilation of bile canaliculi was marked in hyperplastic nodules. Kupffer cells were not seen in the sinusoids. Sinusoidal endothelia had no fenestrae. Transmission electron microscopy revealed the endothelium had a continuous basement membrane. In conclusion, hyperplastic nodule has the intermediate features between liver cirrhotic nodule and liver cell adenoma or hepatocellular carcinoma.

Animals↗

PubMed1982

Iron carbonyl, a tracer for phagocytosis in scanning electron microscopy.

Human peripheral blood mononuclear cells and polymorphonuclear (PMN) leukocytes, separated by Ficoll-Hypaque have been incubated with a preparation containing iron carbonyl, and studied by scanning electron microscopy (SEM) in the backscattered electron imaging (BEI) mode. Iron carbonyl particles were visible only on the cell surface when studied in the conventional secondary electron (SE) mode of the scanning electron microscope. However, ingested iron carbonyl particles were observed in high contrast when the backscattered electrons were selectively collected. The BEI mode of the scanning electron microscope appeared very useful in identifying phagocytic activity in mixed cell populations and in establishing direct correlations, at the level of each individual cell, between surface morphology and phagocytic activity.

Humans↗

PubMed1996

Demonstration of the fine structure of stereocilia in the organ of Corti of the guinea pig by field emission scanning electron microscopy.

A combined perfusion- and immersion prefixation with glutaraldehyde followed by a tannic acid/arginine/osmium tetroxide (TAO) treatment of the guinea pig cochlea is described for field-emission gun scanning electron microscopy (FEG-SEM) observation of the fine structure of the stereocilia of the organ of Corti. Conventional osmium tetroxide postfixation methods in combination with a thin conductive coating failed to show the fine structure of the glycocalyx of the epithelial lining in the endolymphatic compartment of the cochlea, in particular, on the stereocilia surface. The antennulae-like glycocalyx covering of the stereocilia surface of the more pronounced rows of outer hair cells has been demonstrated only in ultrathin sections by means of cationic markers. The side- and tip-links connecting the stereocilia have been demonstrated both in scanning and transmission electron microscopy, although at that time these structures often were considered as artificial. However, they can be visualized with FEG-SEM at low accelerating voltage (2-3 kV), and at appropriate working distance and probe current, in combination with a glutaraldehyde perfusion/immersion prefixation and TAO postfixation. Stereo images enhance considerably the three-dimensional appreciation of the stereocilia with glycocalyx lining and side- and tip-links, proving that these connections are a structural part of the hair cell.

Animals↗

PubMed1975

Scanning electron microscopy of the wall of the third ventricle of the brain of Rana temporia. II. Electron microscopy of the ventricular surface of the pars ventralis of the tuber cinereum.

Scanning electrom microscopy of the ventricular surface of the pars ventralis of the tuber cinereum of the frog Rana temporaria shows that it can be divided in (1) a dorsolateral area, characterized by the presence of very numerous large, solid, bulbous protrusions (2) a medial area, where the large bulbous structures are completely absent and which is diffusely covered with very numerous cilia, (3) a transiotional area located between the two other regions. The large bulbs, shown by scanning electron microscopy, correspond with the end-bulbs of thick ventricular dendrites of nerve cells revealed by transmission electron microscopy. At least many of these intra-ventricular bulbs are dendritic endings of peptidergic neurosecretory neurons, which have been tentatively identified as adenohypophysiotropic neuro-hormone producing neurons (Derickx et al., 1972, 1973a, 1973b). The structural features of the dendritic endings plead in favour of a possible receptive role.

Animals↗

PubMedDate not supplied

Uncombable hair (cheveux incoiffables, pili trianguli et canaliculi) syndrome: brief review and role of scanning electron microscopy in diagnosis.

Uncombable hair syndrome was first described some 3 decades ago as "cheveux incoiffables" and is also known as spun-glass hair and pili trianguli et canaliculi. Both inherited (autosomal dominant and recessive with variable levels of penetrance) and sporadic forms of uncombable hair syndrome have been described, both being characterized by scalp hair that is impossible to comb due to the haphazard arrangement of the hair bundles. A characteristic morphologic feature of hair in this syndrome is a triangular to reniform to heart shape on cross-sections, and a groove, canal or flattening along the entire length of the hair in at least 50% of hairs examined by scanning electron microscopy. Most individuals are affected early in childhood and the hair takes on a spun-glass appearance with the hair becoming dry, curly, glossy, lighter in color, and progressively uncombable. Only the scalp hair is affected. Several conditions are associated with uncombable hair, such as ectodermal dysplasia, retinal dysplasia/pigmentary dystrophy, juvenile cataract, digit abnormalities, tooth enamel anomalies, oligodontia, and phalangoepiphyseal dysplasia. Other syndromes with hair abnormalities may also mimic uncombable hair syndrome clinically and these include, Rapp-Hodgkin ectodermal dysplasia; loose anagen hair syndrome; ectodermal dysplasia, ectrodatyly, cleft lip/palate (EEC) syndrome; and familial tricho-odonto-onchyial ectodermal dysplasia with syndactyly. Unlike other conditions with an uncombable hair component, uncombable hair syndrome alone (cheveux incoiffables, pili trianguli et canaliculi) is not associated with physical, neurologic, or mental abnormalities. In most cases of uncombable hair syndrome, the hair is grossly abnormal in infancy and early childhood, but may have improved manageability later in life. Scanning electron microscopy of hair samples provides definitive evidence for diagnosis of clinically suspected uncombable hair syndrome and eliminates other hair abnormalities from the differential diagnosis.

Chemical Phenomena↗

PubMed1997

[Fornicate structure of blind saccular lymph vessel segments in the conjunctiva--scanning electron microscopy studies].

BACKGROUND: The accepted fundamental element of the initial lymphatic system is a tubular structure (lymphatic capillary), which is present either in the form of a finger-shaped blind-ending protuberance, or in the nature of a plexiform composite arrangement. We were able to demonstrate experimentally that the finger-shaped protuberances, which are known as "initial segments" are in fact temporary filling states. As the filling process continues, these vascular elements become intermediate segments, via which other parts of the vascular network take up the dye. To date there have been no investigations of the internal structure of these apparently blind-ending vessel segments. In this study, lymphographically represented "terminal segments" should be cut away for the purpose of examining the fornix by scanning electron microscopy. Is the internal surface of the fornix regular and unbroken, or are there fissure-like structures which could explain the observed filling processes? MATERIAL AND METHODS: In conjunctiva of bovine eyes (n = 80), interstitial double-contrast lymphography (Berlinblue solution/air) under a slit-lamp microscope was used specifically to search for finger-shaped terminal segments. The conjunctivae had previously been prepared by fixing in polymeric resins. A proportion (n = 21) of the specimens were amenable to examination under the scanning electron microscope. RESULTS: Notwithstanding the observed great variation in the shape of the lymphographically obtained blind-ending structures-in the form of terminations shaped variously like fingers, balloons, domes, pistons or pyramids, terminations with two humps, and terminations shaped like spear heads-scanning electron microscopy revealed within the fornices many relatively uniformly shaped structures in the form of fissures, configured with lips and saw-tooth edges, rather like zip fasteners. These findings are suggestive of preformed connections to neighbouring segments. This appears to be another element, in addition to the familiar flap-like structures, for controlling the circulation of lymph. Does the "initial part" of the lymphatic system now have to be redefined?

Animals↗

PubMed1978

Scanning electron microscopy of primordial germ cells in early chick embryos.

Primordial germ cells (PGCs) of the early chick embryo were examined using scanning electron microscopy. Temporal changes in the form and distribution of surface projections were found to be correlated with migratory phases of PGCs. Non-migrating PGCs were spherical to ovoid with relatively smooth surfaces. Their transition to the migratory phase was first evidenced by a burst of membrane activity. Migrating PGCs became somewhat flattened against the underlying hypoblast (which serves as the substratum for their migration) and exhibited blebs and lamellar processes. The lamellar processes were most prominent at the leading edges of actively migrating PGCs. Overall results of the present study indicates that PGCs found in the germinal crescent area of early chick embryos actively migrate on the dorsal surface of the hypoblast towards posterior embryonic regions.

Animals↗

PubMed1976

Scanning electron microscopy of bone cells in culture.

Embryonic and young rat bone cells have been growing in culture and examined in the scanning electron microscopy (SEM). Compared with cells fixed in situ and taken directly from the animal, the cultured osteoblastic cells were smoother, flatter and more extensive and showed tighter intercellular contacts. Some matrix is formed in culture and undergoes at least partial mineralization as judged by the accumulation of Ca and P measured by energy dispersive x-ray analysis. Findings concerning the morphology of the collagen arrangement were indecisive. Some superficial cells, free of surrounding matrix, resembled osteocytes in normal in vivo bone. This may indicate that a proportion of the extracellular matrix produced by the cultured cells failed to polymerise into recognizable bone matrix, and that osteocytic morphology is not dependent upon the physical characteristics of the bone matrix.

Animals↗

PubMed1978

Model of skin vascularization in Rana esculenta L.: scanning electron microscopy of microcorrosion casts.

Microcorrosion casts of blood vessels in the skin of Rana esculenta L. were examined by means of scanning electron microscopy with particular reference to the subepidermal network of respiratory capillaries. Due to the fact that arteries and veins lie in the deeper layers of the stratum spongiosum of the corium, the respiratory vessels form a morphologically homogeneous network. Functionally, however, this network is subdivided into small areas with a centripetal direction of blood flow. The deep capillary net, situated at the base of the stratum compactum of the corium, is not so dense as the respiratory network and does not directly communicate with it. Alveolar glands of the skin have no effect on the distribution of capillaries in the two networks.

Animals↗

PubMed1991

Fine structure of the glomerular basement membrane of the rat kidney visualized by high-resolution scanning electron microscopy.

The fine structure of the glomerular basement membrane (GBM) of the rat kidney was studied by means of high resolution scanning electron microscopy. Specimens were taken from kidneys perfused with paraformaldehyde, freeze-fractured and then processed with conductive staining. The fractured surface of glomerular tufts exhibited the inner and outer surface of the GBM uncovered by endothelial and epithelial cells. The lamina densa was composed of densely packed granular material together with scattered fibrils. The laminae rarae interna and externa were composed of a meshwork that showed some structural heterogeneities. The meshwork composing the lamina rara interna contained 5- to 9-nm-thick fibrils, had pores 11-30 nm wide, and was associated with granular material except in those places that corresponded with endothelial fenestrae. The meshwork of the lamina rara externa was made up of 6- to 11-nm-thick fibrils, and had smaller pores under the foot processes (10-24 nm wide) than those near the filtration slits (16-32 nm wide). In addition to the meshwork, the lamina rara interna contained microfibrils that were arranged differently depending on the topography of the capillary wall: scattered fibrils had no predominant orientation at the convex side, circumferential bundles lay at the concave side of the peripheral capillary wall, and had a circumferential arrangement in the paramesangial wall.

Animals↗

PubMed1976

Scanning electron microscopy of experimental adiaspiromycosis.

Adiaspiromycotic granulomas of mice experimentally inoculated with fungus Emmonsia crescens Emmons et Jellison 1960 were examined by scanning electron microscopy. There morphology, surface structure, and germinating adiaspores isolated from granulomas are described.

Animals↗

PubMed1991

The microvasculature of the 7,12-dimethylbenz(a)anthracene (DMBA)-induced rat mammary tumour. I. Vascular patterns as visualized by scanning electron microscopy of corrosion casts.

We examined the microvasculature of the 7,12-dimethylbenz(a)anthracene (DMBA)-induced rat mammary tumour by scanning electron microscopy of corrosion casts. An elaborate vascular envelope predominantly consisting of sinusoidal and venular vessels was formed around each tumour nodule. These vessels exhibited various abnormal features, whereas arterioles appeared normal. The abnormal vessels possessed many globular outpouches, possibly representing the site of angiogenesis. An additional capillary layer was seen in the marginal boundary between the tumour and host tissue. The lack of centrifugally extruding vessels in this layer may indicate a poor potency for vascular spread of tumour cells into the adjacent normal tissue. Loop-like or glomerular ingrowths were frequently found on the inner aspect of the vascular capsule, which eventually developed into a dense intranodular plexus. Intranodular vessels often showed focal narrowing, tapering and/or rupturing, possibly due to increased tissue pressure caused by proliferating tumour cells. Those surrounding necrotic portions were extremely dilated with occasional periodic varicosities. The features may be associated with the lessening of the tissue pressure resulting from tumour cell collapse.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1994

Scanning electron microscopy of osteoid osteoma.

We have examined the organic components of the nidus of an osteoid osteoma in 4 patients using scanning electron microscopy. Different organisation of the osteoblastic cells and of the fibrous structures of the osteoid matrix in different zones was demonstrated. These findings indicated a greater degree of immaturity in the centre, as compared with the peripheral area where the process of differentiation was more evident.

Adolescent↗

PubMed1984

The odontoblast process and its branches in human teeth observed by scanning electron microscopy.

Healthy teeth were fixed, resin-impregnated and freeze-fractured. Specimens were critical point-dried and examined by scanning electron microscopy. Odontoblast processes were observed in the inner-, middle- and peripheral dentine. The processes in the inner-third dentine closely approximated tubule wall and could be found in most of the tubules. Some tubules contained a thin fibre besides the odontoblast process. In the middle third of dentine, the processes became thinner, their appearance was cable-like with lateral branches and a wide periodontoblast space could be seen. Processes were seen only in a few tubules of outer-third dentine in both young and aged subjects. They divided into longitudinal and lateral branches and seemed to be connected with one another.

Adolescent↗