A Scanning Electron Microscopic Study of Enamel Surfaces of Incipient Caries

The surface changes of natural incipient caries in human teeth were examined by scanning electron microscopy. Numerous small round depressions due to dissolved prism ends are observed. The prism sheaths seem to be preferentially demineralized, followed by demineralization of prism cores. Perikymata are well-pronounced. Focal holes and relatively large dissolution areas can be present. A new prismatic pattern of destruction with an appearance of fish scales is found. Evidence of remineralization of the incipient carious lesions is seen on the surfaces of the lesions. This study disagrees with the concept of an intact enamel surface layer.     

Peripheral Blood Smears of Myelodysplasia Patients: Scanning Electron Microscope Findings

The utility of scanning electron microscopy in the evaluation of ordinary glass peripheral blood smears of patients with myelodysplasia and those uncertain for myelodysplasia is emphasized. Attention is directed to changes in segmented granulocytes. Comparison of ultrastructural findings in abnormal blood smears with control cases is made. Important findings include reduced cytoplasmic granule number, increased cell size, large cytoplasmic vacuoles, condensation of the peripheral cytoplasm, prominence of large cytoplasmic granules, irregular cytoplasmic perimeter, abnormal nuclear morphology, abnormal cell shape, and a necklace-like arrangement of cytoplasmic granules. Of these findings, reduced cytoplasmic granule number was the most specific finding, while condensation of peripheral cytoplasm was the most sensitive. Combination of these two morphologic findings may provide a strong predictor of myelodysplasia. The study included a limited test of unknown cases evaluated by one author, including two uncertain for myelodysplasia. Pitfalls in evaluating temporary pancytopenia not associated with myelodysplasia are noted.     

The Use of a Desktop Scanning Electron Microscope as a Diagnostic Tool in Studying Fibrin Networks of Thrombo-embolic Ischemic Stroke

Proneness to the formation of tight and rigid fibrin networks has been shown to be independently associated with thrombotic disease. These changes may be visible long before the actual event. Previous research has shown that there is a fundamental difference between fibrin network architecture of controls compared to fibrin networks of patients 48?h post-thrombo-embolic ischemic stroke. This conclusion was made using a high-tech scanning electron microscope (SEM). Here the authors investigate whether ultrastructure of these networks can be successfully analyzed when using a smaller, desktop SEM. Such a screening procedure would not only be inexpensive, but could potentially warn patients of a possible thrombotic event long before any symptoms are prevalent. Platelet-rich plasma, obtained from healthy volunteers and thrombo-embolic ischemic stroke patients (48?h poststroke), was activated by the addition of thrombin. Fibrin networks were compared using a Zeiss ULTRA plus FEG-SEM with InLens and a desktop portable ZEOL SEM (ZEOLNeoScope). This desktop version produces micrographs that may easily be analyzed, and the information gained by studying the micrographs was comparable to that of the Zeiss ULTRA plus FEG-SEM. Such a desktop machine might be used as a screening tool or to identify individuals with risk, before the actual event. In addition, it may provide valuable information in recovering stroke patients.     

扫描电镜观察肿瘤细胞受攻击过程中的形态变化

本文以扫描电镜观察了Ｂ淋巴细胞白血病瘤系细胞（Ｒａｊｉ细胞）在遭受淋巴因子激活的杀伤细胞（ＬＡＫ细胞）攻击时所表现的超微结构外形改变。结果发现ＬＡＫ细胞不仅可主动接近瘤细胞，并在该处出现胞吐分泌象；瘤细胞的主要改变则在与ＬＡＫ细胞的接触处，渐次形成窦穴，甚至遭受该细胞的穿凿性攻击致胞体受损，终而导致死亡解体。研究中还发现ＬＡＫ细胞也有相应地生理性耗损现象。     

Light and Scanning Electron Microscope Examination of the Digestive Tract in Peppered Moray Eel,Gymnothorax pictus (Elopomorpha)

The morphology of the digestive tract of the peppered moray eel, Gymnothorax pictus (G. pictus) (Elopomorpha: Anguilliformes) was examined using both light and scanning electron microscopy. The digestive tract is composed of the esophagus, the stomach, and the intestines; pyloric caeca were absent. The stomach was divided into a cardiac region that was continuous with the esophagus, a body which terminated in a long blind sac, and a pyloric region that was continuous with the intestine. The short intestine possessed several partitions that were created by the mucosal folds within the posterior region. The terminal region of the stomach was characterized by the thick longitudinal muscularis and subserosa, and the gastric glands and microvilli were absent. Ciliary tufts of ciliated cells were observed on the surface of the partition‐like mucosal folds within the intestinal wall. Acidic mucus was secreted throughout the digestive tract. It was suggested that the terminal region of the stomach is specialized for storage of large food items. In addition, it is possible that the partition‐like mucosal folds within the intestine perform a function similar to that of the spiral valve and, and along with ciliated cells, facilitated digestion and absorption. The acidic mucus likely maintained surface epithelium pH and protease activity. Within a phylogenetic context, the absence of a pyloric caeca in G. pictus while possessing an intestine implies that this species is affiliated to groups that had branched off earlier than basal teleosts. Anat Rec, 296:443–451, 2013. © 2013 Wiley Periodicals, Inc.     

Low Temperature Backscattered Electron Imaging in the Study of Human Tissues

A scanning electron microscopic technique for the examination of bulk, fresh, hydrated human tissue is described. Samples of fresh tissue are frozen in liquid nitrogen against a mirror-finished copper block and planed in a cryoultramicrotome before transfer to a low temperature scanning electron microscope. After sublimation of water from the specimen surface, the tissue is examined in secondary electron and back-scattered electron modes. Adjacent pieces of tissue, and those retrieved after backscattered electron observation, can be readily prepared for and examined by light and by conventional transmission electron microscopy.

The method has been tested with multiple blocks taken from 6 cases of human breast carcinoma. In the backscattered electron mode, the infiltrating columns of neoplastic cells can be distinguished from mammary adipose and fibrous tissue. Within a carcinoma, the collagenous stroma, carcinoma cells, and perivascular and perineural infiltrates can be identified. These features have been contrasted with those obtained by light microscopy, by low temperature scanning, and by transmission electron microscopy. This use of back-scattered electron imaging for the investigation of unfixed hydrated tissue offers the possibility that the technique could be of considerable value in the microscopy of very small samples in which, because of a need for subsequent biochemical, histochemical, and immunologic investigation, fixation and dehydration are to be avoided.     

Low Temperature Backscattered Electron Imaging in the Study of Human Tissues

A scanning electron microscopic technique for the examination of bulk, fresh, hydrated human tissue is described. Samples of fresh tissue are frozen in liquid nitrogen against a mirror-finished copper block and planed in a cryoultramicrotome before transfer to a low temperature scanning electron microscope. After sublimation of water from the specimen surface, the tissue is examined in secondary electron and back-scattered electron modes. Adjacent pieces of tissue, and those retrieved after backscattered electron observation, can be readily prepared for and examined by light and by conventional transmission electron microscopy.

The method has been tested with multiple blocks taken from 6 cases of human breast carcinoma. In the backscattered electron mode, the infiltrating columns of neoplastic cells can be distinguished from mammary adipose and fibrous tissue. Within a carcinoma, the collagenous stroma, carcinoma cells, and perivascular and perineural infiltrates can be identified. These features have been contrasted with those obtained by light microscopy, by low temperature scanning, and by transmission electron microscopy. This use of back-scattered electron imaging for the investigation of unfixed hydrated tissue offers the possibility that the technique could be of considerable value in the microscopy of very small samples in which, because of a need for subsequent biochemical, histochemical, and immunologic investigation, fixation and dehydration are to be avoided.     

Bacteria in Biopsies of Human Hypochloridric Stomach: A Scanning Electron Microscopy Study

A long-lasting condition of hypochloridria leads to a bacterial growth both in the gastric lumen and biopsies of human stomach. Some of these bacteria are probably involved in gastric carcinogenesis, due to their capacity of nitrosation. This study was carried out on biopsies taken during endoscopy from both gastric antrum and the body of patients with or without hypochloridria. Scanning electron microscopy observation shows that bacteria, other than Helicobacter pyloridout, found in hypochloridria, can be located not only over but also into and under the mucus layer covering the gastric epithelium. In such areas, mechanical and biochemical damage may occur.     

Immunogold-Silver Staining Method for Lymphocyte Cell Surface Antigens with Light,Transmission Electron,and Scanning Electron Microscopy

Abstract

The immunogold-silver staining (IGSS) method combined with light, transmission electron, and scanning electron microscopy (LM, TEM and SEM, respectively) was used for detecting lymphocyte surface antigens. Two different sizes of colloidal gold particles (5 nrn and 15 nm) were applied as markers and IntenSEII kit as a physical developer for gold particles.

The silver enhanced gold particles were clearly observed on cell surfaces as black dots in LM and TEM and as white dots in SEM equipped with a mixed signal of secondary electron and back-scattered electron (SE/BE) signals. Monoclonal antibody (MAb)-positive cells possessing the complexes on their well preserved surfaces were easily identified among other lymphoid cells at low magnifications of LM or SEM equipped with SE/BE signals. Thus, the IGSS method has a great advantage for a qualitative screening such as the percentage of lymphocyte subsets in a cell suspension. However, the IGSS method was inadequate for semiquantitative study with antigen density on cell surfaces because gold particles enhanced with the physical developer were considerably enlarged, and a silver-gold complex was not considered to show one antigen site on cell surface. (The J Histotechnol 16:217, 1993)     

Acellular Scanning Electron Microscopy of Spicular Renal Amyloidosis

Two human renal biopsies containing glomerular amyloid deposits organized into spicular formations (spicular amyloid) were studied by scanning electron microscopy following removal of the cellular components (acellular SEM). Following SEM studies, portions of the same acellular tissue were embedded in paraffin and plastic for light microscopy and transmission electron microscopy, respectively. Spicular deposits by acellular SEM appear as tapering conical formations interconnected by a delicate branching network of fibrils, which imparts a higher degree of organization than previously appreciated by two-dimensional LM and TEM. Silver stains of paraffin-and plastic-embedded acellular tissue showed persistence of argyrophilia in spicular deposits, while acellular TEM showed that the spicules appeared comprised “purely” of amyloid fibrils without visible contaminating material. We conclude that the argyrophilia of spicular amyloid is an inherent feature of the parallel organization of fibrils rather than a result of incorporation of glomerular basement membrane or cell components and that spicular amyloid deposits have a higher degree of organization than is apparent by two-dimensional studies.     

Scanning Electron Microscopy of Disseminated Superficial Actinic Porokeratosis

A typical skin lesion from a patient with biopsy-confirmed disseminated superficial actinic porokeratosis (DSAP) was examined by scanning electron microscopy. The lesion was rimmed by a prominent but discontinuous cornoid lamella. The cornoid lamella was found to consist of a packed layer of keratinocytes whose orientation varied from parallel to the epidermis at the base of the lesion to perpendicular at the summit of the porokeratotic column. The central core of the cornoid lamella consisted of a tightly packed mass of keratin.     

New Techniques Scanning Electron Microscopy of Acellular Glomeruli in Human Glomerulonephritis: Application of a Technique

Scanning electron microscopy (SEM) has been employed in studies of human and experimental glomerulonephritis (GN), a major contribution being the elucidation of podocyte morphology and the process of podocyte foot process retraction in proteinuric conditions. Application of SEM in GN has been limited however by an emphasis on cell surface alterations while the site of major disease processes, the glomeru-lar basement membrane, has remained hidden from view. A previously reported technique for the preparation of acellular glomeruli from fresh tissue has been adapted for use on frozen human renal biopsies. One case of minimal change disease (MCD) and one case of membranous glomerulonephritis (MGN) have been studied. The acellular glomerular basement membrane of MCD has a lightly textured or granular surface whereas in MGN a striking reticular network of basement membrane has formed perpendicular to the native basement membrane. The immune complexes have been removed. This technique provides a graphic visualization of GBM alterations occurring in glomerulonephritis and is applicable to the study of human as well as experimental model of glomerulonephritis.     

New Techniques Scanning Electron Microscopy of Acellular Glomeruli in Human Glomerulonephritis: Application of a Technique

Scanning electron microscopy (SEM) has been employed in studies of human and experimental glomerulonephritis (GN), a major contribution being the elucidation of podocyte morphology and the process of podocyte foot process retraction in proteinuric conditions. Application of SEM in GN has been limited however by an emphasis on cell surface alterations while the site of major disease processes, the glomeru-lar basement membrane, has remained hidden from view. A previously reported technique for the preparation of acellular glomeruli from fresh tissue has been adapted for use on frozen human renal biopsies. One case of minimal change disease (MCD) and one case of membranous glomerulonephritis (MGN) have been studied. The acellular glomerular basement membrane of MCD has a lightly textured or granular surface whereas in MGN a striking reticular network of basement membrane has formed perpendicular to the native basement membrane. The immune complexes have been removed. This technique provides a graphic visualization of GBM alterations occurring in glomerulonephritis and is applicable to the study of human as well as experimental model of glomerulonephritis.     

Correlative Study of Adult Respiratory Distress Syndrome by Light, Scanning, and Transmission Electron Microscopy

The sequential pulmonary changes occurring in the evolution of adult respiratory distress syndrome (ARDS) were studied in 35 patients by correlative light, scanning, and transmission electron microscopy. The causes of ARDS were diverse, the major ones being sepsis or aspiration. Patient survival ranged from 3 to 51 days. The acute stage in patients surviving 2 to 7 days was characterized by an exudative reaction with a predominance of hyaline membranes. This acute stage merged with and was replaced by a subacute reparative stage in patients surviving 7 to 14 days, which in turn was replaced by a chronic fibroproliferative stage complicated by interstitial pulmonary fibrosis and a deranged acinar architecture. Correlation of findings by scannning electron microscopy with those by light and transmission electron microscopy provided an added dimension to understanding of the evolving stages of ARDS and demonstrated that type 2 pneumocytes contributed to the fibroproliferative stage through organization of hyaline membranes and re-epithelialization of alveoli.     

Correlative Study of Adult Respiratory Distress Syndrome by Light,Scanning, and Transmission Electron Microscopy

The sequential pulmonary changes occurring in the evolution of adult respiratory distress syndrome (ARDS) were studied in 35 patients by correlative light, scanning, and transmission electron microscopy. The causes of ARDS were diverse, the major ones being sepsis or aspiration. Patient survival ranged from 3 to 51 days. The acute stage in patients surviving 2 to 7 days was characterized by an exudative reaction with a predominance of hyaline membranes. This acute stage merged with and was replaced by a subacute reparative stage in patients surviving 7 to 14 days, which in turn was replaced by a chronic fibroproliferative stage complicated by interstitial pulmonary fibrosis and a deranged acinar architecture. Correlation of findings by scannning electron microscopy with those by light and transmission electron microscopy provided an added dimension to understanding of the evolving stages of ARDS and demonstrated that type 2 pneumocytes contributed to the fibroproliferative stage through organization of hyaline membranes and re-epithelialization of alveoli.     

Scanning and Transmission Electron Microscopy of a Craniopharyngioma: X-ray Microanalytical Study of the Intratumoral Mineralized Deposits

This paper discusser the value of scanning electron microscopy (SEM) and x-ray microanalysis in the classification of craniopharyngiomas. This neoplasm shows epithelial nests, cords of cuboid cells, foci of squamous metaplasia, and microcystic degeneration. SEM reveals that the epithelial cysts are lined with elongated cells that possess numerous microvilli and blebs and that some cysts are lined with polyhedral cells. The microvilli are interpreted as characteristic of the fast growing craniopharyngiomas. A microanalytical study of the calcified areas reveals the presence of magnesium, phosphorus, and calcium.     

Scanning and Transmission Electron Microscopy of a Craniopharyngioma: X-ray Microanalytical Study of the Intratumoral Mineralized Deposits

This paper discusser the value of scanning electron microscopy (SEM) and x-ray microanalysis in the classification of craniopharyngiomas. This neoplasm shows epithelial nests, cords of cuboid cells, foci of squamous metaplasia, and microcystic degeneration. SEM reveals that the epithelial cysts are lined with elongated cells that possess numerous microvilli and blebs and that some cysts are lined with polyhedral cells. The microvilli are interpreted as characteristic of the fast growing craniopharyngiomas. A microanalytical study of the calcified areas reveals the presence of magnesium, phosphorus, and calcium.     

Detection of Villous Conidia of Conidiobolus coronatus in a Blood Sample by Scanning Electron Microscopy Investigation

Conidiobolus coronatus is a major insect pathogen belonging to the fungal order Entomophthorales, causing a rare subcutaneous infection of the nasofacial region, resulting in swelling of predominantly the nose, mouth, and perinasal tissue. Later in the course of the infection firm, painless, subcutaneous nodules develop that are attached to the underlying tissues but not to the skin. No morphological studies are available in the literature on the morphology of C. coronatus in vivo and all morphological studies have been conducted on in vitro cultures. Here the authors report on the ultrastructural pathology as seen with a scanning electron microscope (SEM) of villous conidia of C. coronatus, detected in a 37-year-old woman who presented to the casualty department at Pretoria Academic Hospital, South Africa with left-sided facial pain and headache. The diagnosis of C. coronatus was confirmed by LightCycler real-time flourescence PCR technique. Research shows that typically diagnosis of the pathogen is established only on histological examination, and in over 85% of cases cultures for the causative organism is negative. This pathogen has not previously been found in a blood sample and the authors present for the first time the morphology of C. coronatus in blood using the SEM.     

Scanning electron microscopic observations of surface prismless enamel formed by minute crystals in some human permanent teeth

It might have been recognized that surface prismless enamel with no prism sheaths or boundaries is formed by needle-shaped crystals in parallel arrangements and shows almost the same crystal size as the underlying prismatic enamel. This study found that some island- and band-shaped prismless enamel in third molars and dome-shaped prismless areas in the region adjacent to the partial hypoplastic enamel of a premolar were formed by minute crystals compared with the underlying prismatic enamel when observing afibrillar cementum and cementicle-like structures by scanning electron microscopy. Their minute crystals became smaller in size towards the natural enamel surface. In the band- and dome-shaped prismless enamel, the minute crystals abruptly changed to the usual-sized crystals in the underlying prismatic enamel, although the minute crystals in the dome-shaped prismless areas tended to show random arrangements. The band-shaped prismless layers might be similar to afibrillar cementum, but shallow Tomes’ process pits were present in the natural surface and no appositional laminations were observed in the fractured surface. The minute crystal formation in such prismless regions might be caused by the remarkable decline of ameloblast activity immediately after the disappearance of Tomes’ processes producing prism structures surrounded by prism sheaths during the final stage of amelogenesis.     

Collagen Fibrils in the Odontoblast Layer in the Teeth of the Rat and the House Shrew,Suncus murinus by Scanning Electron Microscopy Using a Maceration Method

It is not well known whether there are gaps in the tight junctions between odontoblasts and whether the fluid flows from the pulp to the predentin through these gaps. The collagen fibrils in the odontoblast layer were investigated using a maceration method in order to show the existence of the gaps between tight junctions of the odontoblasts. The mandibles containing teeth of the rat and the house shrew were digested by NaOH maceration and revealed the architecture of the collagen fibrils under scanning electron microscopy. The collagen fibrils went from the pulp, through the odontoblast layer, and were woven into the collagen network of the predentin in all teeth used in this study. Thick bundles of collagen were seen in the odontoblast layer at the pulp horn of the rat molars. Because there are many collagen fibrils in the odontoblast layer, it is considered that the tight junction of the odontoblast is of the discontinuous type.