Contribution of Scanning Electron Microscopy and Associated Analytical Techniques to the Study of Atherosclerotic Disease

Human carotid atheroma has been examined by scanning electron microscopy (SEM) utilizing both secondary and backscattered electron detectors and transmission electron microscopy (TEM) both at conventional and high voltage. Different cytochemical techniques have been used to map elastic fibers, proteoglycans, calcium, non esterified cholesterol. By immunocytochemistry the distribution of factor VIII related antigen and actin has been studied. With SEM it was possible to detect aspects of carotid plaques not appreciated when using other conventional techniques. With TEM some modifications of the structural and/or functional features of connective tissue macromolecules have been observed. The occurrence of anomalous collagen has been shown. The fine investigation of endothelial cells, smooth muscle cells and the intercellular matrix components has supplied information of particular morpho-functional significance, thus allowing the development of new ideas on the complex pathogenetic mechanisms of atherosclerosis and suggesting some important anatomo-clinical correlations

Cell Ultrastructure in Disease

The doctor of today must adopt the \u27cellular way of thinking\u27 in the evaluation of diseases. This ultrastructural outlook provides him with much indispensable information that also serves a practical purpose. A diseased cell organelle is at the basis of every clinical sign and any attempt of therapy must be aimed at that specific point of lesion. We intend, in the light of a long experience, to propose to clinicians a new way of thinking in which a precise correlation between symptoms and sub-microscopic changes of the cell is considered. Many different examples amply justify this proposal. Electron microscopy can contribute by enabling a) identification of structural sub-cellular modifications suitable for the finest differential diagnosis, b) more and more complete understanding of pathogenic pathways of various diseases, c) the establishment of guidelines for precise pharmacological interventions at the molecular level

Scanning Electron Microscopy Application in Clinical Research

Our personal experience on the application of scanning electron microscopy in cardiology, gastroenterology and ophthalmology is reviewed. SEM has not yet significantly contributed to myocardium pathology. However, in the near future, SEM could be a reliable technique to complete the information available from other sources. As to atherosclerosis, SEM allowed us to improve our knowledge of the early stages of the disease; some pathological features, not always detected by conventional morphological examinations, can be documented. An important contribution to gastrointestinal pathology was made by SEM investigations both in the staging of some important diseases (i.e., coeliac disease, peptic ulcer, Crohn\u27s disease, ulcerative colitis) and in the follow-up of mucosal changes during therapy. In the ophthalmological field,SEM provided three-dimensional new information to clinicians, who are familiar with the biomicroscopic images. Our experience in hematology is still limited. However, in the lost few years SEM joined to immunocytochemistry allowed us to characterize cell populations in several blood diseases. Some procedures of particular interest in the management of human bioptic specimens are stressed in order to get to a complete correlative microscopy. We conclude that continuous and simultaneous correlations have to be carried out between SEM and other methods and instruments available for morphological investigation

Beam Voltage Effects in the Study of Embedded Biological Materials by Secondary Electron Detectors

Thin and semithin sections were extensively examined by the secondary electron (SE) detector in a conventional scanning electron microscope (SEM), and in a transmission electron microscope with a scanning attachment (STEM). Various para-meters, in particular the beam voltage, were shown to affect the final SE image (SEI). As for SEM observation, a surface contrast was imaged at low primary electron (PE) voltages (0.6-2 kV), whereas a subsurface contrast predominated at higher energies (15-30 kV). In STEM, significant differences were not detected by varying the PE in the 20-100 kV range. Surface and subsurface in-formation was simultaneously imaged even though the SEI were better resolved at the highest energy

Characterization of Mucus Glycoconjugates in Normal Human Conjunctiva by Lectins in Light Microscopy, Transmission and Scanning Electron Microscopy

Maintenance of tear film in normal conditions is dependent on 1) mucus layer integrity and 2) the presence and distribution of conjunctival epithelial cell microvilli. In the present work a new methodology has been developed to gain correlative information about microprojection assessment and mucus composition, from the same specimen, by Light Microscopy (LM), Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). We have characterized the glycosidic residues secreted by goblet cells in normal human conjunctiva, by means of four lectins (WGA, ConA, PNA and SBA), conjugated with FITC for LM and with colloidal gold for TEM and SEM. The cytochemical reactions were performed on histological sections of paraffin-embedded material and on semithin and ultrathin sections of both Epon embedded material directly processed for TEM and of blocks recovered from SEM and reprocessed for TEM. WGA, ConA, PNA and SBA receptors were found to be constituents of the mucus produced by goblet cells in human conjunctiva. The granules of the so-called second mucus system (SMS) cells were labelled mainly by WGA. A difference in the quality of glycoconjugates between goblet cells and SMS cells has been also demonstrated. Our results provide an improved method to evaluate alterations of tear film that occur in many conjunctival diseases

Scanning Electron Microscopy in the Study of Campylobacter Pylori Associated Gastritis

The close association between Campylobacter pylori (CP), gastritis and peptic ulcer is now well established. Moreover increasing evidence has been collected of a major etiological role of CP in type B chronic gastritis. For this reason, searching for CP is essential in all patients with upper gastrointestinal symptoms. Scanning electron microscopy (SEM) is a most reliable technique for studying the distribution of microorganisms and their relationship to the gastric mucosal surface. The aim of this paper is to compare SEM to other routine methods of detection for CP, such as Giemsa staining on histological sections and Urease Microtiter Test (MT) on fresh tissue and to investigate the surface morphology of gastric mucosa colonized by CP and to correlate it with the histopathological picture. Thirty-seven biopsies taken from the gastric body and the antrum of 22 patients were used for each type of determination. The different parameters were graded semiquantitatively. Histology showed a normal mucosa in 4 cases, chronic superficial gastritis in 12 and chronic atrophic gastritis in 21 cases. SEM was more sensitive than histology and Urease MT in detecting Campylobacter pylori. This is due to the patchy distribution of this bacterium on gastric mucosa. For this reason SEM should always be performed when routine tests are negative. The presence of CP correlated significantly (p \u3c 0.001, Spearman Rank Correlation Test) with the neutrophilic infiltrate, thus with the activity of the gastritis. The CP associated gastritis has no distinctive surface features other than the presence of the bacterium SEM morphology of surface gastric mucous cells suggests that CP does not damage the lining epithelium directly. Neutrophils and inflammatory mediators could be involved in the production of the mucosal lesions

Scanning Electron Microscopy, X-Ray Microanalysis and Immunohistochemistry on Worn Soft Contact Lenses

The deposits accumulated on the surfaces of soft contact lenses are a cause of problems for the wearer of these lenses, as the deposits are never completely removed by the available washing solutions. Therefore it appears of interest to investigate the composition of these deposits. In this paper we review the major findings in the literature and, in addition, present our personal experience. We have studied new, continuously and daily worn soft contact lenses by scanning electron microscopy (SEM), X-ray microanalysis and immunohistochemistry. We have carefully evaluated preparative methods, and we can conclude that SEM and X-ray microanalysis are best carried out on unfixed, air-dried lenses. The deposits present consist mainly of mucus, especially on the tarsal side of the lenses. Chloride and potassium, coming from the tear fluid, as well as sulfur, derived from proteins, were found. Calcium was very rarely detected. IgG, IgA, IgE and C3c complement fractions were found only on the outer surfaces and not within the lens. We believe that the best characterization of the deposits is achieved by means of correlative techniques on the same lens. In fact, this approach integrates morphology and composition

Corsican pine (Pinus laricio Poiret) stand management: Medium and long lasting effects of thinning on biomass growth

With the aim of acquiring better comprehension of the ecological and productive aspects of the management of pine forests, we monitored logging damage and evaluated the effects of thinning on stand growth 20 years after the treatment in a Pinus laricio Poiret stand in central Italy. The objectives of the present study were to estimate the injury levels to the remaining trees after thinning; to assess logging damage in the long-term by monitoring residual trees at the end of thinning; to evaluate the effect of damage on the radial growth of trees; to assess the stand dynamics in relation to injury levels and the treatment applied in a twenty-year range; to understand a possible treatment return time; and to evaluate the existence of the "thinning shock". The results were that 20 years after treatment, the stand dynamics showed a complete recovery; logging damage did not affect the radial growth of P. laricio over time; a second treatment seem to be sustainable starting from the fifteenth year after the previous treatment; and the thinning shock can be clearly evaluated in the first six to seven years after the treatment

Strategies to Mitigate the Effects of Soil Physical Disturbances Caused by Forest Machinery: a Comprehensive Review

Purpose of Review: Ground-based mechanized forest operations can cause severe soil disturbances that are often long lasting and detrimental to the health of forested ecosystems. To reduce these soil disturbances, focus is being increasingly directed at identifying and using appropriate mitigation techniques. This systematic review considered 104 scientific articles and reported the main findings according to four core themes: terrain-related factors, operational planning, machine modifications, and types of amendments used to mitigate machine-induced soil impacts. Recent Findings: For terrain-related factors, most severe disturbances occur on machine operating trails exceeding 20% slope and that soil bulk density and rut depth show greater increases in fine-textured soils. When considering operational planning, trafficability maps proved to be helpful in reducing the frequency and magnitude of soil damages as well as the length of trails needed within harvest sites, especially if they are regularly updated with weather information. Machine modifications, through high flotation tires, use of extra bogie axle, lower inflation pressure, and use of steel flexibles tracks, are highly researched topics because of the considerable upside in terms of machine ground pressure distribution and increased traction. Two main types of amendments emerged to mitigate soil disturbances: brush mats and mulch cover. Brush mats created from harvesting debris can spread the load of a machine to a greater area thereby lowering peak loads transferred to the soil. Brush mats of 15–20 kg m−2 are being recommended for adequate soil protection from harvesting operations. Summary: To conclude, we outline recommendations and strategies on the use of soil mitigation techniques within cut-to-length forest operations. New research opportunities are also identified and discussed. Considering single factors causing machine-induced soil disturbances remains important but there is a pressing need for having a multi-disciplinary approach to tackle the complex problems associated with machine/soil/plant interactions

Strategies to Mitigate the Effects of Soil Physical Disturbances Caused by Forest Machinery: a Comprehensive Review

Purpose of Review Ground-based mechanized forest operations can cause severe soil disturbances that are often long lasting and detrimental to the health of forested ecosystems. To reduce these soil disturbances, focus is being increasingly directed at identifying and using appropriate mitigation techniques. This systematic review considered 104 scientific articles and reported the main findings according to four core themes: terrain-related factors, operational planning, machine modifications, and types of amendments used to mitigate machine-induced soil impacts. Recent Findings For terrain-related factors, most severe disturbances occur on machine operating trails exceeding 20% slope and that soil bulk density and rut depth show greater increases in fine-textured soils. When considering operational planning, trafficability maps proved to be helpful in reducing the frequency and magnitude of soil damages as well as the length of trails needed within harvest sites, especially if they are regularly updated with weather information. Machine modifications, through high flotation tires, use of extra bogie axle, lower inflation pressure, and use of steel flexibles tracks, are highly researched topics because of the considerable upside in terms of machine ground pressure distribution and increased traction. Two main types of amendments emerged to mitigate soil disturbances: brush mats and mulch cover. Brush mats created from harvesting debris can spread the load of a machine to a greater area thereby lowering peak loads transferred to the soil. Brush mats of 15-20 kg m(-2) are being recommended for adequate soil protection from harvesting operations. To conclude, we outline recommendations and strategies on the use of soil mitigation techniques within cut-to-length forest operations. New research opportunities are also identified and discussed. Considering single factors causing machine-induced soil disturbances remains important but there is a pressing need for having a multi-disciplinary approach to tackle the complex problems associated with machine/soil/plant interactions