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PubMed1980

[Scanning electron microscopic study of keratohyaline granules in the oral epithelium of rats].

Scanning electron microscopy of rat buccal epithelium on deparaffinized or epon-etched sections provided observations of intracellular structures especially of keratohyaline granules. Cell-walls and nuclei were easily observable and the two types of keratohyaline granules already seen in transmission electron microscopy were identified namely intracytoplasmic or intranuclear single granules and composite granules with a heterogeneous structure which appeared clearly in the scanning method. Tridimensional information from scanning electron microscopy adds significantly to knowledge of keratohyaline granules morphology, so far studied with the transmission method only.

Animals↗
PubMed1985

Pathogenesis of the mouse forelimb deformity induced by acetazolamide: an electron microscopic study.

Scanning electron microscopic observations after removal of the epidermis from developing limb buds reveal a fine mesenchymal cell process meshwork (CPM). The relationship between apical ectodermal ridge (AER) development and CPM density was investigated and related to the postaxial reduction deformities induced by acetazolamide (AA). AA was given orally to pregnant mice at 9 A.M. and 4 P.M. of day 9 and 9 A.M. of day 10 (VP = 0) in a dose of 1,000 mg/kg. Forelimb ectrodactyly, especially on the right, was the most common deformity observed. Scanning electron microscopic observations showed that the AER in AA-treated right forelimb buds did not extend postaxially as far as that in controls. The postaxial region with the hypoplastic AER became defective. Scanning and transmission electron microscopic observations revealed that in control and treated right forelimb buds, the CPM underneath the typical AER was sparser than that underneath the dorsal or ventral non-ridge epidermis. However, in treated right forelimb buds, the CPM underneath a hypoplastic AER was denser than that underneath the normal AER. These findings suggest that AA-induced deformity results from a disturbance of the AER-mesenchymal interactions.

Abnormalities, Drug-Induced↗
PubMed1978

Scanning electron microscopic observations of tooth germ in tissue culture with special reference to the migration of epithelial cells.

Tooth germ derived from the mandible of newborn mice was used in this study. The enamel organs were dissected and attached directly to coverslips without using the plasma clot. By this method it was possible, for the first time as far as is known, to attain preparations in which the major part of the outgrowth from the explant consisted purely of epithelial-like cells which probably were aneloblasts. Abundant desmosomes and tonofilaments were confirmed by transmission electron microscopy. Under the scanning electron microscope this outgrowth of epithelial cells revealed characteristic intercellular connections which were divided into four types. 1)In the part nearest to the explant, cell boundaries were indicated with a large number of short microvilli. 2)In the zone beyond the first type, the intercellular connection was represented by bridge-like processes firmly combined with each other. 3)In a still further zone, the tips of bridge-like processes were free from the cell connection and extended to the adjacent cells with the advance of cell migration. 4)In the most peripheral part of the explant, the cytoplasmic processes were capable of further expansion. These cells were soon separated from the adjacent cells to migrate as free cells.

Animals↗
PubMed1984

Transmission and scanning electron microscopic studies of human sperm heads extracted with 8 M urea, 1% mercaptoethanol and different concentrations of salt.

Transmission (TEM) and scanning (SEM) electron microscopic studies were performed on the human sperm heads extracted with (a) 1% Triton X-100, 1% mercaptoethanol (ME) and (b) 8 M urea, 1% ME together with increasing concentrations of NaCl ranging from 0.2 to 0.6 M. In the TEM study, the extraction of the nuclear material was first observed when the heads were treated with 8 M urea and 1% ME, with the majority of the chromatin remaining as 400-550 A thick interconnecting cords and oval bodies. At 0.2 M NaCl the cords and bodies were further separated but linked together by extremely thin 20-50 A fibers. Between 0.3 and 0.5 M NaCl the chromatin bodies within the sperm heads began to be extracted, first at the central part and progressively towards the periphery. Finally, at 0.6 M NaCl only the chromatin cords forming the periphery of the heads remained. In the SEM study, the sperm heads remained unbroken up to the treatment with 8 M urea, 1% ME and 0.2 M NaCl. Between 0.3 M and 0.5 M NaCl the majority of heads were disrupted to form interlacing chromatin cords of 400-550 A thick while the unbroken heads exhibited surface with cross-weaving cords. At 0.6 M NaCl all heads were disrupted and the remaining chromatin existed mostly as exoskeleton of former sperm heads. Protein gel electrophoresis showed that histones and nonhistones were removed from the chromatin when the treatment reached 0.2 M NaCl, whereas protamines started to be removed at 0.3 M, and totally removed at 0.6 M NaCl; HP1 was the first protamine fraction to be extracted.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Optimisation of the environmental scanning electron microscope for observation of drying of matt water-based lacquers.

Environmental scanning electron microscopy (ESEM) modifies conventional SEM through the use of a partial gas pressure in the microscope specimen chamber. Like conventional SEM, it has the resolution to image structure on the submicron lengthscale, but can also tolerate hydrated specimens if water vapour is used in the specimen chamber. This ability to image aqueous specimens leaves ESEM uniquely placed to study in situ drying in polymer latexes. However, there are two key practical difficulties associated with in situ drying. First, the size of the latex particles: larger latex particles are typically around 500 nm in diameter. Although ESEM can resolve structure on this lengthscale without difficulty, the magnification required results in radiation damage of the specimen due to the electron beam. This means that a given region can be imaged only once during film formation, so the evolution of particular features cannot be followed. Second, the change from ambient temperature and pressure to the ESEM conditions of 7 degrees C and 7.5 torr (100 Pa) can subject the specimen to a very high evaporation rate, which can disrupt film formation. The inclusion of a drop of water in the specimen chamber is shown largely to alleviate this, enabling successful imaging of film formation in the lacquer. Instead of the polymer latex itself, this work concentrates on a matting lacquer with silica inclusions. The silica matting agent particles are 1-10 microm in size, allowing for a lower magnification to be used, massively reducing specimen damage. Furthermore, the contrast during drying is much enhanced in the presence of silica. The images reveal the silica as bright regions against a darker background of polymer and water. Film formation shows the transition from a uniform, featureless aqueous solution to a polymer film with silica particles present on the surface. The appearance of individual silica particles can be followed. The particles are generally revealed quite early, after a few minutes of drying time. As film formation progresses, these same particles appear larger and more distinct. Few new particles are revealed at longer film formation times.

Journal Article↗
PubMed1989

Comparison between light and scanning electron microscopic findings in cells stained by Riu's method.

Difficulties with cell recognition are sometimes encountered in surface structural studies of biomedical specimens with scanning electron microscopy (SEM). If cells are stained and examined first by light microscopy (LM), then the specificity of their surface structures when observed by SEM can be reassured. Although other staining methods have been advocated, Riu's stain, which employs eosin yellow, methylene blue and azure I was tested in this study. A total of 28 specimens, including 10 pleural effusions, 4 ascites, 9 peripheral blood cells and 5 bronchial brushings, were collected for comparison. Free cells were fixed with 2% glutaraldehyde and allowed to form sediment on poly-L-lysine precoated plastic cover slips. They were stained with Riu's A and B solutions and observed with a light microscope. A lattice composed of cut lines made by a surgical knife served as the cell finder. Cells of interest were photographed before they were fixed in OsO4, dehydrated and dried in liquid CO2 at a critical-point temperature. Observation with a scanning electron microscope showed that the particular cells could be found within 10 minutes. Cell loss was minimal. Configuration of the cells was preserved and no distortion was detected in their fine surface structure. This study confirms that Riu's stain is suitable for comparative purposes between LM and SEM.

Cells↗
PubMed1988

Terminal sprouting in partially denervated muscle of the mouse: a scanning electron microscopic study.

Terminal sprouting in the mouse gastrocnemius muscle was examined by scanning electron microscopy after partial denervation. After one of the two muscle nerves in the medial head was cut, terminal sprouts arose from the outer edge of the intact motor endplates and grew out onto a connective tissue layer on the muscle fibres. The sprouts were very slender along their length, although some had a varicose appearance. The terminal tip of the sprouts was swollen in an amoeba-shaped configuration, forming a growth cone. Several shorter projections surrounded the initial part of a long terminal sprout, whilst in the centre the varicosity had a spindle shape like a diamond: the former most likely indicated the processes of a Schwann cell, and the latter may be a Schwann cell soma. Such swelling patterns suggested that the sprout initially grew out from a growth cone and then the Schwann cells migrated into the growing sprout. The sprouts had no synaptic connections with their muscle fibres at least during the growth cone-forming stage. No structural changes to guide the growing terminal sprouts could be recognized on the flat surface of the muscle fibres.

Animals↗
PubMed2005

Effects of Nd:YAG laser irradiation on root canal dentin wall: a scanning electron microscopic study.

OBJECTIVE: The purpose of this study was to evaluate, by scanning electron microscopy (SEM), the effects of Nd:YAG laser irradiation applied perpendicular or parallel to the root canal dentin wall. METHODS: Thirty human teeth were divided into two groups: Group A (20 roots), laser application with circular movements, parallel to the dentin root surface; and Group B (10 roots), roots cut longitudinally and laser applied perpendicular to the root surface. Group A was subdivided into A1 (10 roots), laser application with 100 mJ, 15 Hz and 1.5 W; and A2 (10 roots) with 160 mJ, 15 Hz, and 2.4 W. Group B was subdivided into B1 (10 hemisections) and B2 (10 hemi-sections) with parameters similar to A1 and A2. Four applications of 7-sec duration were performed, with a total exposure of 28 sec. SEM evaluations were made in the cervical, middle, and apical thirds, with 500x and 2000x magnifications. Morphological changes scores were attributed, and the results were submitted to Kruskal Wallis statistical test (5%). RESULTS: Significant statistical differences were found between groups Aand B (p = 0.001). In groups A1 and A2, few areas of dentin melting were observed. In groups B1 and B2, areas of melting dentin covering dentin surface were observed. CONCLUSIONS: It was concluded that intracanal laser application with circular movements (parallel to the surface) produces limited morphological changes in root canal dentin wall.

Dental Pulp Cavity↗
PubMed1975

Identification of nerve fibres in the scanning electron microscope.

The use of silver as a "stain" for nerve fibres in scanning electron microscopy (SEM) preparations has been investigated. Samples of cardiac tissues were treated according to the Bielschovsky silver impregnation method. Following embedding in paraffin, successive sections were selected for light microscopy and for SEM studies, respectively. The silver impregnated fibres, when examined in SEM preparations, appeared nearly white against a greyish background of cardiac tissue. They were therefore easy to localize even at a low magnification. These nerve fibres were identified in the same tissue, but different blocks by means of transmission electron microscopy (TEM) studies and by fluorescence microscopy.

Animals↗
PubMed1977

Scanning electron microscopic surface morphology of isolated hepatocytes from normal and premalignant rat liver.

Scanning electron microscopy was performed on hepatocytes isolated after collagenase perfusion of livers from rats fed 2-acetylaminofluorene (AAF) in the diet for 6--8 weeks and on hepatocytes from control rats. The premalignant AAF-cells showed a greater variation in cell size and shape. They also exhibited a reduced number of microvilli and more blebs and other protrusions on the surface than hepatocytes from control animals.

2-Acetylaminofluorene↗
PubMed1990

The morphological variability of neuromuscular junctions in the rat extraocular muscles: a scanning electron microscopical study.

Six morphologically distinct types of neuromuscular junctions were identified by scanning electron microscopy in the rat extraocular muscles: two diffuse and four focal types. The diffuse junctions, spreading out extensively over the muscle fiber surface, were characterized by two types of varicose swellings (or terminal varicosities) of nerve endings. One type consisted of several ramifying nerve endings and shallow postsynaptic depressions with poorly-developed junctional folds. The other type consisted of a single axon and formed many synaptic contacts along the long axis of a muscle fiber. Round synaptic depressions facing the varicosities contained several junctional folds. The focal junctions, confined to an oval area on the muscle fiber surface, were characterized by the complexity and variability of their subneural apparatuses. Four different types of apparatuses, i.e., focal junctions, were found: 1) an apparatus consisting of labyrinthine gutters with numerous slit-like junctional folds, 2) apparatuses consisting of a large number (more than 20) of cup-like depressions with either a small number of pit-like junctional folds or 3) numerous slit-like ones, and 4) an apparatus consisting of a small number (about 10) of cup-like depressions with a few junctional folds. The findings indicate that the rat extraocular muscles contain six different types of muscle fibers.

Animals↗
PubMed1992

Microcirculation of the rat pancreas, with special reference to the insulo-acinar portal and insulo-venous drainage systems: a further scanning electron microscope study of corrosion casts.

Microcirculation in rat pancreas was studied by scanning electron microscopy of resin vascular casts and by light microscopy of India ink-injected and sectioned tissue samples. In the scanning survey of the casts, islets larger than 30 microns in diameter counted no less than 400 in the adult rat pancreas. They were located either in the exocrine lobules (intralobular islets, counting 210 or more), or in the interlobular tissue spaces and along the secretory ducts (extralobular islets, 190 or more). Every islet received arterial blood via one or more proper arterioles. These afferent vessels first divided in the peripheral zone of the islet consisting of A and D cells and later extended deeper to form a capillary network in the islet core consisting of B cells. Blood originating from this capillary network left the islet via efferent vessels. This microvascular pattern may favor the regulation by A and D cells over the secretory activity of B cells. The intralobular islets gave their efferent vessels to the capillary bed of the exocrine tissue of the lobule, thus forming an insulo-acinar portal system. When the lobule was relatively small in size, superfluent blood was led directly to veins via insulo-venous drainage vessels. The intralobular islets sometimes issued one or more long translobular portal vessels reaching adjacent lobules. The extralobular islets issued either insulovenous vessels draining to interlobular veins, or extralobular insulo-acinar portal vessels supplying adjacent lobules.

Animals↗
PubMed1980

Cochlea of the human fetus: a scanning electron microscope study.

Fine structures of the human fetal cochlea were observed by scanning electron microscopy. The study aimed to make the knowledge on the developmental microanatomy of the cochlea more accurate. The temporal bones of fetuses were removed and the membranous portions of the cochleas were prepared for observation. In a 14-week 6-day old fetus, the hair cells were arranged mainly in four rows. The sensory hairs differed in appearance from those in the adults. The innermost or first row hair cells corresponded to the inner hair cells and revealed certain characteristic structures. From the second to the third or outermost row, a rather uniform hair pattern with a bud-like appearance was noted. Neither W nor V letter formation of sensory hairs was found. One strong kinocilium was identified with its thick base; it was located lateral to the outermost stereocilia. With older fetuses, 22 weeks 2 days and 24 weeks 0 day of age, the hair patterns closely resembled those of the adult with the exception of the presence of a short kinocilium on the outer hair cells and a slim kinocilium on the inner hair cells. The present study indicates that structures including the sensory hairs and their attachment to the tectorial membrane, the Reissner's membrane and the stria vascularis essentially complete their morphologicjal development in 6 months after gestation.

Cochlea↗
PubMed1988

[Scanning electron microscopic representation of the tegument of the cysticercus of Taenia saginata].

By scanning electron microscopy we found heteromorph microtriches in the tegumental surface of the praeadult and its bladder. But this polymorphism is caused by three unimorph parts, namely the head region, the midbody and the bladder. The types of microtriches are heterogeneous in regard to the shape (from conical to cylindrical), the size (from 0.37 to 4.5 micron in length and 0.055 to 0.092 micron in diameter) and the density (from 6.3 to 25 microtriches/micron 2). An attempt was made to determine the relative increase in the tegumental surface of the cysticercus of T. saginata. The relation of actual surface area to a corresponding area without microtriches is OF = nA + 1/1 - nB. In this study, the factor of the increase in the tegumental surface (OF) ranged from the head region (6.3x) to the midbody (1.4x -1.7x) and the bladder (21x). By transmission electron microscopy fine threads were demonstrated in the apical surface of the microtriches. These fine threads raised the adhesive function of the microtriches in the course of the infection of the final host as well as in the migration in the digestive tract. A relation between shape, size and density of the microtriches and the body volume is postulated.

Animals↗
PubMed1986

[Age-related changes and sex differences in bone resorption in the mouse femur: a light and scanning electron microscopic study].

Bone resorption surfaces can be identified as rough areas by scanning electron microscopy. In this study, for understanding the principle of bone resorption and influences of gonads on the bone resorption in long bones, osteoclasts and bone resorption surfaces in the femur were qualitatively and quantitatively examined by light and scanning electron microscopy in 250 dd-mice of both sexes at 4, 7, and 14 weeks of age; some of the animals were gonadectomized at 4 weeks and examined at 7 and 14 weeks. The numbers of osteoclasts and bone resorption surfaces on the distal trabecular bones in the femur were large at 4 and 7 weeks and became smaller at 14 weeks. The area-proportion of the bone resorption surfaces in the distal trabecular bone region was large at 4 weeks and decreased with age. The number of osteoclasts and the number and area-proportion of the bone resorption surfaces were greater in females than males at 7 and 14 weeks. The sex-differences after puberty were large at 14 weeks than 7 weeks. After gonadectomy, the above values were not changed in females but significantly increased in males. In gonadectomized mice, the values were greater in males than females at 14 weeks. The results suggest that bone resorption activities change corresponding to the growth rate of the femur and receive inhibitory influences by male gonadal products, possibly androgenic hormones.

Aging↗
PubMed1984

Scanning electron microscopic observations of the oocyst, sporoblast and sporozoite of Plasmodium yoelii yoelii.

Scanning electron microscopy was used to study the surface characteristics of the oocyst, sporoblast and sporozoite of Plasmodium yoelii yoelii. Observations were made of the sporogonic stages of 6-12 day infections of the malaria parasite in Anopheles stephensi. Oocyst and sporoblast development were not synchronous. The surface of the undifferentiated (early stage) oocyst appeared smooth, whereas that of differentiated (late stage) oocysts were rough or wrinkled. The wall of the differentiated oocysts showed numerous micropores at higher magnification (x15,000-20,000) the biological significance of which is not known. Small, bud-like satellite bodies were seen attached to some oocysts. Various forms of different stages of the sporoblast were described. Sporozoite budding took place on the surface of the sporoblast body. The sporozoite was elongate, curved and with a blunt anterior end.

Animals↗
PubMed1977

Hydrosalpinx simplex as seen by the scanning electron microscope.

Five cases of hydrosalpinx simplex were studied by light microscopy and scanning electron microscopy (SEM). Comparison was made with normal fallopian tube epithelia. By light microscopy numerous ciliated cells as well as nonciliated cells were found in both hydrosalpinx and normal tubal material. In hydrosalpinx material the epithelium was found to be compressed to one-sixth its usual height. The SEM survey of large areas of hydrosalpinx did not reveal any deciliation. In fact, the mucosa of the hydrosalpinx did not differ conspiciously from that of a healthy fallopian tube. However, some nonciliated cells with collapsed areas were revealed by SEM. The significance of the compressed areas is unknown.

Adnexal Diseases↗