SEARCH · PubMed Health

Results for “Microscopy, Electron, Scanning”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,261 records · Page 70Linked to original sources

PubMed1975

Scanning electron microscopy of the articular surfaces of the hip joint disorders.

The specimens from 19 femoral heads with various abnormalities are observed with scanning electron microscopy, comparing with light microscopic findings. Villi and plica appearance implies the fibrillated surface of degenerated cartilage with fibrous tissue proliferation. Beside these findings, craters with their associated undulations of concentric circles or guitar-shaped figures are visualized in the areas histologically showing the exposed cartilage of the deep zone. The undulations are correspondent to the fine clefts of the shredding surface. From the observations reported here, the existence of the lamellar system around the chondrocyte lacuna is proposed in the deep matrix of the articular cartilage.

Aged↗

PubMed1991

Ossicular erosion by cholesteatoma: investigation by scanning electron microscopy utilizing a new preparation technique.

A new technique for removing the soft tissues from middle ear ossicles to prepare them for scanning electron microscopy is described. The technique involved use of a solution of hypochlorite. The bony surface of normal ossicles was studied as a control group after preparation by the technique and no morphological distortion was observed. Ossicles eroded by cholesteatoma were then studied, and we propose that the erosion occurs in three stages; pumicing, pitting and cavitating. The mucoperiosteum of normal ossicles and otosclerotic foci were also studied.

Cholesteatoma↗

PubMed1990

[A scanning electron microscopy study of the normal rabbit appendix].

The surface relief of the mucous membrane of the normal rabbit appendix was studied under scanning electron microscopy. Two different types of surface relief were identified. One consisted of relatively regular crests and grooves of the mucosa, the other one exhibited scattered crater-like openings into which "heads of lymphatic nodes" were inserted to varying extent and which were separated from the surface mucosa by broad alveolar cavities. Since adequate terminology has not yet been coined for the description of the observed structures, the authors use the terminology of classical histology and from analogous descriptions of other reliefs.

Animals↗

PubMed1986

On the ovarian bursa of the golden hamster. I. Scanning electron microscopy of the inner surface and stomatal orifices.

The inner surface of the ovarian bursa in the golden hamster was observed by scanning electron microscopy. There were numerous discontinuities in the bursal epithelium. Crevice-like gaps were formed between irregularly spaced epithelial cells, and the subepithelial connective tissue was exposed to the bursal cavity through the gaps. Through circular defects in the epithelial lining or pores, which were less than 20 microns in diameter, either the subepithelial connective tissue or stomatal orifices were visible. There were smooth surfaced areas lined with lymphatic endothelium, instead of bursal epithelium, which was continuous from the wall of the lymphatic vessel to the inner surface of the bursa. These areas were not present in all bursae, but if they were present, stomatal orifices consistently opened in them. Stomata in the ovarian bursa had two types of orifices, (1) circular orifices opening predominantly in smooth surfaced areas and measuring up to 50 microns in diameter; (2) jagged orifices opening usually in pores and measuring less than 10 microns in diameter. Blood cell components derived from ovulation entered lymphatics via stomata. Bursal fluid and small particles may drain into lymphatics directly via stomata and indirectly by diffusion through gaps, pores and connective tissue. Judging from the structural appearance of the stomatal orifices, the degree of opening of jagged orifices may change in response to changes in the cavity, while circular orifices may be stable openings.

Animals↗

PubMedDate not supplied

[Scanning electron microscopy of the cytoskeleton of the aortic endothelial cells of mature and aged rats].

The aortic endothelial cells' cytoskeleton was visualized using scanning electron microscopy of detergent-extracted cells. It is shown that the aortic endothelial cells' cytoskeleton undergoes structurization during aging. The cytoskeleton structurization is supposed to be an adaptive reaction which increases stability of intracellular contacts and cell adhesion with the underlying substrate.

Aging↗

PubMed1979

The chick embryo late primitive streak and head process studied by scanning electron microscopy.

Changes in cell shape during the formation of the head process and regression of Hensen's node have been examined by scanning electron microscopy in a series of chick embryos from stage -5 to stage -8. The endoderm was removed from embryos mounted for New culture so that the mesoderm could be viewed from the ventral surface. As the primitive streak shortens its cells flatten and lose the flap-like processes characteristic of earlier stages. The notochord differentiates and its cells become transversely orientated, then re-align along the embryonic axis between stage 6 and stage -8. At the same time a split or cleft appears between notochord and head mesoderm, and extracellular fibrils are formed which are the first sign of the formation of a notochordal sheath.

Animals↗

PubMed1994

Collagen fiber arrangement in temporo-mandibular joint (TMJ) disks from human subjects with functional diseases. Scanning electron microscopy investigations.

Twelve articular disks from patients with temporo-mandibular joint (TMJ) arthropathy were studied and compared with two normal disks. Scanning electron microscopy (SEM) examination of the surfaces and of longitudinal and cross-sections of the disks allowed the observation of the arrangement of the collagen fiber component in different parts of the disk. The superficial part of the articular disks appears to be formed by rather compact fibers. The internal portion is usually formed by bundles of collagen fibers in sheets, alternating with isolated fibers arranged in a parallel or irregular way. In some samples, blood vessels were observed. Our investigations suggested that the appearance of vascularization is the first remarkable histological change that can be observed in functionally abnormal articular disks.

Collagen↗

PubMed1994

Scanning electron microscopy of acinar cells of rat submandibular salivary glands.

1. The submandibular salivary gland of rats was observed by high-resolution scanning electron microscopy employing the aldehyde-osmium-DMSO-osmium method. 2. The intracellular membranous components and sponge-like structures of basement membrane containing the fine collagen fibrils of acinar cells were clearly identified in three-dimensional images. The granular endoplasmic reticulum and Golgi apparatus showed the luminal surface. The mitochondria were small, ranging in diameter from 0.3 to 0.5 microns, and revealed their cristae. The secretory granules ranged in diameter from 0.3 to 1.4 microns. Ribosome granules were attached to the surfaces of cisterns, and measured 20 to 25 nm in diameter. 3. The contact areas between the acinar cells revealed numerous cytoplasmic protrusions. In the striated duct cells, the mitochondria were arranged vertically and surrounded by basal infoldings of the plasma membranes. At high magnification, the mitochondrial cristae were visualized in their three-dimensional characteristics.

Animals↗

PubMed1993

[Contribution of scanning electron microscopy in children with lithiasis].

Infrared spectroscopy (IR) was used as the preferential method for determination of the composition of calculi and scanning electron microscopy (SEM) for observation of the IR shape. Our results show the role of SEM for visualisation of the internal ultrastructure and architecture of calculi in children. The authors confirm their previous hypothesis that phosphates favour the nucleation of other compounds, and demonstrate the presence of some trace elements which could play an important role in lithogenesis (eg Si).

Child↗

PubMed1995

The formation of filopodia-like protrusions during preparation of cell suspensions for scanning electron microscopy.

The standard preparation of cell suspensions (e.g., blood cells, cell suspensions derived from monolayer cultures or from various tissues, etc.) for scanning electron microscopy (SEM) includes fixation of the cells in suspension and subsequent dehydration and critical point drying (CPD) of the cells after their preliminary attachment to the special substrata. In the course of the SEM examination of cell suspensions of various origins, unusual morphological cell surface structures, filopodia-like protrusions (FLP), were consistently detected in 3-20% of the cells in the populations. FLP can be effectively observed only by using a stage tilt angle of no less than 30 degrees. FLP were single or multiple thin threads extending from basal parts of a spherical cell and attaching to the substratum surface used. FLP strikingly resembled substratum-attached filopodia formed by a viable cell at its earliest stages of spreading. The percentages of the cells with FLP were not significantly affected by the character of cell fixation (primary aldehyde fixation alone or primary aldehyde with subsequent OsO4 post-fixation) or the raising of the temperature and pressure inside the CPD bomb. It seems that the protrusions imitating the natural cell surface structures can probably be formed at later stages of the preparation of cell suspensions for SEM, namely during dehydration and (or) CPD when the cells undergo substantial shrinkage. One of the possible mechanisms by which the cell shrinkage could induce FLP formation follows. A prefixed spherical cell which settles down to the substratum sticks to it at some discrete points on the cell surface. As a result of the subsequent cell shrinkage, FLP could be formed and then stretched, connecting the same points on the cell surface with the points of the initial cell-substratum adhesion.

Animals↗

PubMed1996

Casting methods of scanning electron microscopy applied to hemal lymph nodes in rats.

Hemal lymph nodes of the para-aortic group in rats were examined by scanning electron microscopy (SEM) using the corrosion cast technique. The vasoarchitecture of hemal lymph nodes was described in cast specimens filled from the abdominal aorta. A dense system of capillaries arranged in the mode of a meshwork could be represented in the nodal cortex. The postcapillary venule (PCV) with wide vascular lumina provided the prevailing vessel type of the deep cortex. Sphincter-like narrowings of the capillary lumen appeared at the sites where capillaries merged with the PCV. These vascular segments were interpreted as structures controlling the hemodynamics of the joining PCV thereby providing appropriate conditions for homing lymphocytes. No evidence was obtained from the casts for an open circulation in hemal lymph nodes. The intranodal lymphatic pathways were studied in specimens interstitially injected with resin. The fine lymphoid tissue spaces were characterized by special cast patterns reflecting the structural differentiation of certain nodal compartments. Afferent lymphatics could be clearly identified in casts with a retrograde filling from the subcapsular sinus. Very spacious intermediary sinuses and wide meshed medullary sinuses could be represented in those casts as well, thus allowing ample space for the encounter of large macrophages with red blood cells.

Animals↗

PubMedDate not supplied

Development of mouse submandibular gland studied by field emission scanning electron microscopy.

The ultrastructural organization of mouse submandibular gland from 15 days gestation to 180 days of age was studied by field emission scanning electron microscopy. At 15 days of gestation several groups of acini, intercalated and striated ducts were present. They consisted of numerous pyramidal and/or polyhedral cells with spherical or elongated nuclei and short microvilli. At 3 days after birth different shapes of acinar structures covered by a network of fine collagen bundles were observed. The acinar portions corresponded to the terminal tubules and showed the acinar cells containing immature secretory granules. Fractured specimens of ducts revealed a flat surface with large central nuclei. At 14 days after birth acinar terminal portions possessed a round shape; branches of either intercalated and striated ducts were also observed. Gap junctions and interdigitations were numerous at the base of acinar cells. At 30 days after birth the acinar terminal portions and striated ducts revealed a large number of secretory granules. Acinar cells showed a pyramidal shape and basal nuclei. Freeze-cracked surfaces of the striated ductal cells evidenced also a pyramidal shape. Secretory granules ranged from 0.3 to 1.2 microns in size and were clearly observed by infoldings of the basement membranes. At 90 days after birth the ultrastructural features were more differentiated when compared with the previous ages. The freeze-cracked specimens showed very numerous secretory granules in all acinar and striated ductal cells. The granules occupied almost all the apical region of the cells. The outer surface of the basement membrane of acinar and myoepithelial cells was constituted by a spongy-like material covered by fine collagen fibrils. At 180 days after birth numerous secretory granules were seen either in acinar and ductal cells. A morphofunctional polarization of the cell was finally clearly observed in that the cytoplasmic organelles were concentrated in the basal portion whereas the secretory granules were located in the apical region of the cells.

Animals↗

PubMedDate not supplied

Detection of calcifications in breast biopsies by scanning electron microscopy.

The identification of microcalcifications in breast biopsy specimens is a common and important task for the surgical pathologist that may sometimes be problematic. Although visualized by preoperative mammographic and operative specimen radiography, some cases may fail to reveal calcifications by histopathologic examination or occasion laborious and time-consuming study to confirm sparse calcifications. The present study demonstrates how conventional bright-field and polariscopic light microscopy did require considerable effort to confirm rare calcification. On the other hand, scanning electron microscopy was employed directly on a routine slide and provided definitive visual and physical proof, e.g., by means of energy dispersive x-ray microanalysis of a rare calcification on a slide previously judged to be negative for calcium and in a short period of time. Recent instrument advances in high voltage beam stabilization and in the ability to vary the pressure of the scanning electron microscope in the vicinity of the specimen now allow complete insertion of a diagnostic glass slide with only trivial preparation. The report, although brief, raises important questions regarding the extent and prevalence of breast calcifications.

Adult↗

PubMedDate not supplied

[Scanning electronic microscopy of the small intestine in persistent diarrhea].

Persistent diarrhea very often leads children to malnutrition. It has become the major cause of death resulting from acute diarrhea episodes in developing countries. In order to determine the ultrastructural alterations of the small bowel that occur in the syndrome, 16 infants with severe persistent diarrhea were studied, utilizing light microscopy and the scanning electron microscope. Stool and jejunal fluid samples were collected for culture, rotavirus, ova and parasite search. Enteropathogenic agents were isolated in stools from 11 (68.7%) patients and bacterial proliferation in the small bowel was detected in 11 (68.7%) patients. EPEC strains were the most frequent enteropathogenic agent isolated both from stool and jejunal fluid cultures. The stool cultures revealed the presence of the following enteropathogenic microorganisms: EPEC 0111 in four, EPEC 0119 in one, EAggEC in five, Shigella flexneri in two, and Shigella sonnei in one; mixed infections due to EAggEC associated with EPEC 0111 were seen in two patients. The light microscopic analysis revealed that 56.2% of the patients suffered moderate villous atrophy most frequently associated with effacement of the microvilli, intracytoplasmatic vacuolization, increased number of multivesicular bodied and increased lymphocytic and eosinophylic infiltration in the lamina propria. The scanning electron microscopic analysis revealed in all cases shortening of the villi and enterocyte derangements; very often there was a total lack and/or effacement of the microvilli; in half of the patients there was a mucoid material covering the enterocytes tightly adhered to the apical epithelium surface. The scanning ultrastructural alterations observed in these patients are probably due to an association of factors brought about by the presence of enteropathogenic microorganisms and the resulting food intolerance that is responsible for perpetuation of diarrhea.

Diarrhea, Infantile↗

PubMed1996

Problems in preparation of chromosomes for scanning electron microscopy to reveal morphology and to permit immunocytochemistry of sensitive antigens.

Although much information about chromosome structure and behaviour has been obtained using light microscopy, greater resolution is needed for a thorough understanding of chromosome organisation. Scanning electron microscopy (SEM) can provide valuable data about these three-dimensional organelles. The introduction of methods using osmium impregnation of methanol-acetic acid-fixed chromosome spreads revolutionised matters, producing life-like images of chromosomes. Nevertheless, it became clear that osmium impregnation introduced various artefacts, although the resulting images were still useful. Methanol-acetic acid-fixed chromosomes are, in fact, flattened on the glass substratum, and the 3-dimensional appearance obtained after osmium impregnation is the result of swelling during this process. At the same time, the fibrous substructure of the chromosomes becomes much coarser. More recently a number of alternative methods have become available for studying chromosomes by SEM. Isolated chromosomes, that have not been allowed to dry during preparation, retain a 3-dimensional appearance without osmium impregnation, and the same is true of methanol-acetic acid-fixed chromosomes that have been treated with 45% acetic acid and processed without drying; however, these methods do not permit the routine production of intact metaphase spreads. Use of cytocentrifuge preparations obviates the use of acetic acid fixation and osmium impregnation, produces intact metaphase spreads, and permits the immunocytochemical detection of antigens that are easily destroyed by routine fixation procedures.

Acetic Acid↗

PubMed1976

Scanning electron microscopy of normal uterine cervix, carcinoma in situ and squamous cell carcinoma. Preliminary findings.

Colposcopically directed punch biopsy specimens of the uterine cervix were taken from women in whom Papanicolaou smears indicated cytological abnormalities. Half of each specimen was processed for scanning electron microscopy and half for light microscopy. The surface morphology of normal cervical, metaplastic and frankly carcinomatous epithelia and epithelia of carcinoma in situ, as seen under the scanning electron microscope, was compared with the appearance revealed by Papanicolaou smears, and haematoxylin- and eosin-stained sections.

Carcinoma in Situ↗

PubMed1977

Effect of pretreatment with ethanol containing fluoride on etched enamel surface as evaluated by scanning electron microscopy, optical microscopy, and tensile bond strength measurement.

The effects of pretreatment with a fluoride-containing ethanol solution on etched enamel surfaces before application of sealant were examined using scanning electron microscopy, optical microscopy, and tensile bond strength determinations. The results suggested that when etched enamel surfaces are treated with ethanol containing no more than 250 ppm fluorine in potassium fluoride, there is no interference with the bonding of the sealant to the treated, etched anamel surface.

Acid Etching, Dental↗

PubMed2001

Scanning electron microscopy determination of string mozzarella cheese in gastric contents.

As part of a suspected homicide investigation, a sampling of the gastric contents from the victim was forwarded to the U.S. Food and Drug Administration's Forensic Chemistry Center (FCC) for analysis of specific, selected components. The victim was known to have consumed string mozzarella cheese, as a snack, less than 24 h before his disappearance and the subsequent discovery of the body. The investigation sought to confirm or dismiss speculation the victim may have been fed a meal or eaten additional food prior to his death. Analysis of the stomach contents involved examination by stereoscopic light microscopy (SLM) and isolation, processing, and analysis of suspect materials by scanning electron microscopy (SEM). Several wax-like, off-white to cream-colored objects were noted by SLM examination and removed from the gastric contents. Through a series of fixation, sectioning, drying, and coating steps, these objects were prepared for analysis by SEM. Comparison of the suspect material with laboratory control string mozzarella cheese showed excellent correlation between the analyzed samples, confirming the suspect material from the stomach contents as string mozzarella cheese.

Cheese↗