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PubMed1977

Advantages of megavolt electron microscopy in biological research.

New electron microscopes, operating within the megavolt range have opened important prospects for scientific research. These microscopes were, at first, mainly used by physicists and metallurgists; but nowadays more and more biologists are interested in high voltage electron microscopy: they have obtained important and significant results. The present paper gives more information concerning experiments that have been achieved in Toulouse with our two big instruments working at 1 million volts (1 MV) and three million volts (3 MV).

Cell Wall↗
PubMed1976

Developing protoscoleces of Echinococcus granulosus on the outer surface of the brood capsule, detected by scanning electron microscopy.

By means of scanning electron microscopy, stalked protrusions were observed arising from the outer surface of intact brood capsules of Echinococcus granulosus. Histological studies showed these protrusions to be developing protoscoleces. However, complete development is not attained and the protoscoleces eventually die. It is suggested that external development is a result of overcrowding within the brood capsule.

Animals↗
PubMed1975

[Evaluation of the interaction between blood and foreign material in the pump oxygenator during open-heart surgery in infants by scanning electron microscopy (author's transl)].

Scanning electron microscopy was used to elucidate the interaction between blood and foreign material in the pump oxygenator during open-heart surgery in 7 infants. The loss of platelets upstream of the blood pump is caused by thrombogenicity. The pump itself causes massive destruction of platelets and red blood cells; thromboembolie up to 100 mu and foreign body particles up to 200 mu are being detached from the wall of the tubing to a large extent. The particulate matter is trapped in arterial line filter. Particles up to 40 mu and cellular aggregates up to 60 mu can pass through the filter and enter the patient's systemic circulation.

Blood↗
PubMedDate not supplied

Transmission electron microscopy in hematological diagnosis.

Transmission electron microscopy (TEM) is still a very useful adjunct for hematological diagnosis in the era of molecular techniques. In this article, the main applications of TEM to the cellular identification of normal myeloid cells, the study of dyserythropoietic conditions, myelodysplastic syndromes, congenital dyserythropoietic anemias, acute myeloid leukemias, and lymphoproliferative disorders, as well as the application of ultrastructural cytochemical reactions in hematological diagnosis, are reviewed.

Blood Platelets↗
PubMed1996

Differentiation of females in Sergentomyia sensu stricto (Diptera: Psychodidae) using scanning electron microscopy of pharyngeal armatures.

Scanning electron microscopy of external ornamentation and internal armature of the pharynx was used to identify females of Sergentomyia sensu stricto. Five species from the eastern Mediterranean basin were compared; S. minuta clearly was separated from species of the fallax-group. Within the fallax-group, S. fallax was distinguished readily by its heart-shaped pharynx and the difference in armature between the dorsal and lateral plates.

Animals↗
PubMed2002

The Big Eye in the 21st century: the role of electron microscopy in modern diagnostic neuropathology.

Electron microscopy (EM) remains a powerful and even essential tool in modern diagnostic neuropathology. tumors are still encountered that defy histological or immunohistochemical classification, and EM can often provide answers in these cases. Tumors of the CNS for which EM is useful include unusual or atypical variants of meningioma, ependymoma, and schwannoma; oligodendroglioma-like tumors composed of small "clear" cells; and small "blue cell" tumors of childhood. EM is of great value in identifying site of origin for metastatic adenocarcinomas of unknown origin-an under-recognized and under-utilized potential for this technique. EM is useful in the diagnosis of peripheral nerve sheath tumors and gastrointestinal autonomic nerve tumors. EM is also important in the evaluation of certain congenital, inherited and metabolic diseases-including ceroid lipofuscinoses, CADASIL syndrome, certain myopathies, and mitochondrial encephalomyopathies--and of certain toxic and drug-induced peripheral neuropathies. An important application of EM is its utility in initiating a workup of an atypical tumor or metabolic condition, for which clinical and histological clues point in no obvious direction. In these situations, EM may provide either an answer outright (including answers to questions not asked) or important clues that guide further workup and narrow the range of diagnostic possibilities.

Central Nervous System Diseases↗
PubMed1986

Red pulp of the spleen in autoimmune haemolytic anaemia and hereditary spherocytosis: morphometric light and electron microscopy studies.

Morphometric light and electron microscopy studies on perfusion-fixed spleens from 6 patients with autoimmune haemolytic anaemia and 18 patients with hereditary spherocytosis showed increased relative (and absolute) volumes of red pulp and absolute volumes of pulp cords when compared to 10 controls and 16 patients with immune thrombocytopenia without haemolysis. The mean erythrocyte volume density of the red pulp and mean erythrocyte area were significantly increased, and more of the erythrocytes' profiles were closer to being circular than in the controls. The changes within the splenic red pulp were qualitatively identical in the 2 cases of haemolytic disease, being quantitatively more pronounced, however, in hereditary spherocytosis than in autoimmune haemolytic anaemia.

Adolescent↗
PubMed1988

Chromatin and nuclear envelope of freeze-fractured, neuronal interphase nuclei, resolved by scanning electron microscopy.

High-resolution scanning electron microscopy (SEM) has previously been used to study intracellular detail, including chromatin. It has, however, been commonly carried out either on cellular subfractions or following extraction methods to visualize detail. In the work presented here, intracellular detail of neurons of the dorsal root was visualized in situ by viewing freeze-fracture faces obtained after hypotonic expansion. This procedure permits the detailed resolution, by SEM, of juxtanuclear and intranuclear detail to a degree impossible without hypotonic dispersal. In agreement with work previously reported, nuclear chromatin of these interphase cells presents largely as 30-nm fibers, with a next higher hierarchical structure imparted by swelling in magnesium chloride. Detailed analyses showed that particles as small as 10-nm nucleosomes comprising the 30-nm chromatin fiber could be resolved, with "end-on" views of such fibers showing 5 nucleosomes per helical turn of the fiber. Chromatin fibers positioned subjacent to nuclear pores, or associated with "nuclear spaces" communicating with nuclear pores, were frequently found to be resolved as clusters, in an apparently more decondensed conformation, rather than tightly coiled into the 30-nm fiber. In addition, details of the nuclear envelope, including nuclear pores and perinuclear filaments as well as membranes of the endoplasmic reticulum, decorated with ribosomes, were clearly resolved.

Animals↗
PubMed1992

Morphologic analysis of serous effusion cells by scanning electron microscopy.

The authors used scanning electron microscopy (SEM) to examine the cells obtained from serous effusions of patients affected with a neoplasm or benign disease. Cellular morphology was studied in non-neoplastic effusions to distinguish benign cells from cancer cells with which they are almost always suspended in malignant effusions. Tumor cells differ in some features such as shape, size, arrangement and especially in surface structures (microvilli), the latter being very noticeable when using this method. The investigation enabled us to note several changes in the cell surface that could reflect particular activities of the cells themselves. For this reason we believe that the technique may be considered very useful to gain knowledge of cellular morphology. However, it cannot be considered suitable for making routine diagnostic conclusions.

Adult↗
PubMed2006

Wet electron microscopy with quantum dots.

Wet electron microscopy (EM) is a new imaging method with the potential to allow higher spatial resolution of samples. In contrast to most EM methods, it requires little time to perform and does not require complicated equipment or difficult steps. We used this method on a common murine macrophage cell line, IC-21, in combination with various stains and preparations, to collect high resolution images of the actin cytoskeleton. Most importantly, we demonstrated the use of quantum dots in conjunction with this technique to perform light/electron correlation microscopy. We found that wet EM is a useful tool that fits into a niche between the simplicity of light microscopy and the high spatial resolution of EM.

Actins↗
PubMed1987

The evaluation of endothelial damage following corneal storage: a comparison of staining methods and the value of scanning electron microscopy.

Staining techniques and scanning electron microscopy (SEM) were used to assess damage to the endothelial cells following corneal storage. The aim was to establish whether these assays are useful in the assessment of endothelial integrity following corneal storage. Four groups ensured a range of normal and damaged endothelial cells: 1) fresh; 2) stored for 7 days in a moist chamber; 3) stored by the cryopreservation method of Capella and Kaufman; 4) damaged by rapid freezing with a cryoprobe. Trypan blue (TB), nitroblue tetrazolium (NBT), acridine orange (AO), fluorescein diacetate (FDA) and ethidium bromide (EB), were used to stain the endothelial layer. SEM was carried out on duplicate samples. Staining with NBT resulted in low cell counts due to loss of cells. There was no significant difference between the extent of damage measured by TB, AO or FDA, but it was shown that staining with FDA and EB can distinguish between damaged and intact cells. Tissue stored for 7 days in a moist chamber had a reduced number of intact cells compared to fresh tissue, and tissue stored by the Capella and Kaufman technique gave a reduced number of intact cells compared to both these control and storage groups. SEM showed surface perforation was characteristic of injured cells, rather than complete disruption. FDA has a theoretical advantage over the other stains, and should provide a more accurate appraisal of defects of cell membrane integrity. For this reason, the use of FDA with EB to stain the endothelium, with SEM carried out on duplicate samples, were preferred as assays to use in the development of corneal storage.

Animals↗
PubMed1976

[Peculiar capillary convolution of the parietal pleura. III. Electron microscopy studies].

By means of electron microscopy and ultrahistochemical research it has been attempted to detail the structure and explain the function of the pleural tufts of the parietal pleura present in the ventral mediastinum of dogs. This led to the discovery that the varions forms present for the surface-enlarging pleura protusions in actuality exhibit corresponding morphological characteristics. As a special formation of the serous lamina of parietal pleura, they are covered by an occasionally incomplete mesothel unit. The parenchyma of these organs is compinsed of a macrophage-rich outer border zone and of a vessel-canying central zone. The experimental in vivo application of cationized ferritin in the pleura-space clearly indicated a high resorptive metabolism of the mesothel and of the pluripotential mesenchym cells. The higher incidence of lymphoplasmatic cell-forms in the proximity of the central vessels along with leucocytic cell infiltrations fulfill an immunocellular and phagocytic function. The structure of the cell population of the pleural tufts partaking on the resorption of matter out of the pleural space has been discussed in detail. The in vivo application of a cationized ferritin solution for the purpose of studying these resorptive processes has been critically judged.

Animals↗
PubMed1976

Human chromatin and chromosomes studied by scanning electron microscopy: progress and perspectives.

Scanning electron microscopy (SEM) has been utilized for the past several years for the study of whole-mount preparations of human chromosomes. Cell cycle-dependent changes in chromatin can be demonstrated easily. Chromomeres, which are mass accumulations at complementary points along each chromatid, provide a basis for the "banding" patterns produced by various stains used in light microscopy. In a highly condensed metaphase chromosome, only a rare free fiber end is seen, suggesting that a single chromatin fiber folds into a chromatid. The presence of interchromosomal fibers suggests that the DNA molecule (i.e., the chromatin fiber) might be folded into more than one chromosome. The specificity of the 9q+/22q-Ph1) translocation in chronic myelogenous leukemia and the evidence for nonrandom translocation abnormalities in adult acute leukemia suggest that either the linear integrity of the chromatin fiber comprising several chromosomes is real or that the nuclear membrane attachment site of individual chromosomes results in specific, adjacent chromosomes which are available for induction of nonrandom translocations.

Chromatin↗
PubMed2001

Quantitative analysis of sharp-force trauma: an application of scanning electron microscopy in forensic anthropology.

Scanning electron microscopy (SEM) has occasionally been used by anthropologists and forensic scientists to look at morphological characteristics that certain implements leave on bone. However, few studies have addressed techniques or protocols for assessing quantitative differences between tool marks on bone made by different bladed implements. In this study, the statistical variation in cut mark width was examined between control and test samples on bone using a scalpel blade, paring knife, and kitchen utility knife. Statistically significant differences (p < .0005) were found between cut marks made by the same knife under control and test conditions for all three knife types used in the study. When the control sample and test samples were examined individually for differences in mean variation between knife types, significant differences were also found (p < .0005). While significant differences in cut mark width were found, caution should be used in trying to classify individual cut marks as being inflicted by a particular implement, due to the overlap in cut mark width that exists between different knife types. When combined, both quantitative and qualitative analyses of cut marks should prove to be more useful in trying to identify a suspect weapon. Furthermore, the application of SEM can be particularly useful for assessing many of these features.

Bone and Bones↗
PubMed2002

Scanning electron microscopy of Trichuris trichura.

Scanning electron microscopy (SEM) studies have been carried out on adult and ova of T. trichura to provide the additional topographical details which are not obtainable by the light microscopy. The egg of T. trichura has a chitinous shell which consists of layers of dense lamellae and bordered by a limiting membrane. An operculum and a collar made of chitin form the opercular area. The lamallae of the egg shell are diffuse with numerous micropores. Cuticular pores are found scattering on the surface of the adult T. trichuira. The spicule sheath in male is cylindrical and covered with spines of different shape, size and distribution along its length. Spines are compact proximally, reduced in number on the middle part and lacking distally. SEM of the cloacal part showed paracloacal papillae.

Animals↗
PubMed2002

[Optimization of structural characteristics of a root canal wall during retrograde tooth filling on a basis of scanning electron microscopy data].

Studies by scanning electron microscopy showed that dentin of the root stump (resection of the root apex is an obligatory condition of retrograde filling) has numerous regular dentin tubules, in contrast to the apical part of the root. Mechanical treatment of dentin during preparation of the platform for retrograde filling leads to the formation of a thick "lubricating" layer on the surface of these platform. This layer consists of corpuscles of destroyed tissue substance (smudge) and completely covers the ends of dentin tubules, thus preventing the formation of strong bonds between the filling material and dentin surface. Treatment (pickling) of the platform surface with the conditioner notably improved the adhesion of Russian filling material Dentis to dentin. The best adhesive effect of retrograde filling was attained with Kemfil, the material requiring no pickling pretreatment.

Adhesiveness↗
PubMed2005

Rapid viral diagnosis: role of electron microscopy.

Starting in the 1960, electron microscopy (EM) became widely applied also in viral diagnosis. During the 1970th and 80th, many new agents were characterized from diagnostic cell cultures and clinical specimens. The wide introduction of ELISA- and PCR-techniques as well as cost-arguments recently reduced the role of EM in routine viral diagnosis. Compared to other diagnostic techniques, however, EM excells by speed and "open view", i.e. by the ability to detect also the "un-expected" without the need for specific reagents. As shown in 2003 by the elucidation of the SARS pandemia and the human monkeypox outbreak in US, EM is well suited as a safe, front-line diagnostic method in infectious diseases emergencies and/or in possible bioterrorist attacks.

Forecasting↗
PubMed1991

[Subendocardial vascular plexus of the human ventricular myocardium in ontogenesis studied by scanning electron microscopy].

By means of scanning electron microscopy of native and corrosive preparations peculiarities of endocardium of the papillary-trabecular apparatus of the human heart ventricle and its vessels have been studied in ontogenesis. Folds of the endocardium increase its contact area with blood and also increase reserve of its elasticity at diastole. The subendocardial vascular plexus is formed by capillary-like venous sinusoids. They situate in the direction to the compact myocardium at the depth of 300-500 mcm. They are supposed to perform resorptive functions of nutritive substances and oxygen from blood, which is in the ventricular cavities and to smooth blood pressure between blood in the ventricular cavities and vessels of the compact myocardium.

Adolescent↗