scholarly journals POLYESTER-METHACRYLATE EMBEDMENTS FOR ELECTRON MICROSCOPY

1962 ◽  
Vol 12 (3) ◽  
pp. 615-621 ◽  
Author(s):  
Frank N. Low ◽  
Max R. Clevenger
Keyword(s):  
Electron Microscopy ◽  
Heavy Metal ◽  
Fine Structure ◽  
Organic Solvents ◽  
Polyester Resin ◽  
Butyl Methacrylate ◽  
Metal Compounds ◽  
Tert Butyl Hydroperoxide ◽  
Polyester Matrix ◽  
Volatile Materials

It has been found that tissues fixed for electron microscopy and dehydrated in acetone can be embedded in mixtures of n-butyl methacrylate and polyester resin. Activation with 1 per cent tert-butyl hydroperoxide followed by 12 to 48 hours at 60°C produces blocks that section well with glass knives. The ribbons are cleared of methacrylate by heat (200–250°C for 1 hour) and/or immersion in organic solvents (CCL4, acetone-ether). After removal of the methacrylate the residual polyester matrix provides thermostable and insoluble support for the tissue. Its insolubility permits staining by immersion of cleared preparations in organic solvents carrying heavy metal compounds in solution. Clearing by heat stabilizes section-grid relationships. The removal of volatile materials by clearing substantially reduces contamination of both specimen and microscope. Tissue fine structure is well preserved in these preparations.

scholarly journals DNA AND THE FINE STRUCTURE OF SYNAPTIC CHROMOSOMES IN THE DOMESTIC ROOSTER (GALLUS DOMESTICUS)

1964 ◽  
Vol 23 (1) ◽  
pp. 63-78 ◽  
Author(s):  
James R. Coleman ◽  
Montrose J. Moses
Keyword(s):  
Electron Microscopy ◽  
Heavy Metal ◽  
Fine Structure ◽  
Electron Microscope ◽  
Meiotic Prophase ◽  
Gallus Domesticus ◽  
Feulgen Staining ◽  
Synaptinemal Complex ◽  
Relationship Of ◽  
The Relationship

The indium trichloride method of Watson and Aldridge (38) for staining nucleic acids for electron microscopy was employed to study the relationship of DNA to the structure of the synaptinemal complex in meiotic prophase chromosomes of the domestic rooster. The selectivity of the method was demonstrated in untreated and DNase-digested testis material by comparing the distribution of indium staining in the electron microscope to Feulgen staining and ultraviolet absorption in thicker sections seen with the light microscope. Following staining by indium, DNA was found mainly in the microfibril component of the synaptinemal complex. When DNA was known to have been removed from aldehyde-fixed material by digestion with DNase, indium stainability was also lost. However, staining of the digested material with non-selective heavy metal techniques demonstrated the presence of material other than DNA in the microfibrils and showed that little alteration in appearance of the chromosome resulted from DNA removal. The two dense lateral axial elements of the synaptinemal complex, but not the central one to any extent, also contained DNA, together with non-DNA material.

Validation of the expert methodology «Detection of condensed traces of the gunshot residue containing heavy metal compounds on various objects by scanning electron microscopy and X-ray microanalysis»

2021 ◽  
Vol 87 (12) ◽  
pp. 63-72
Author(s):  
S. A. Smirnova ◽  
I. B. Afanasyev ◽  
G. I. Bebeshko ◽  
G. G. Omel’yanyuk
Keyword(s):  
Electron Microscopy ◽  
Heavy Metal ◽  
Scanning Electron Microscopy ◽  
Electron Microscope ◽  
Standard Sample ◽  
Gunshot Residue ◽  
Test Results ◽  
Metal Compounds ◽  
X Ray ◽  
Scanning Electron

We present and discuss the results of the validation of a forensic qualitative testing technique which consists in the detection of condensed traces of the gunshot residue (GSR) in the form of individual microparticles on the objects under study and their identification by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) using a scanning electron microscope Mira III (Tescan, Czech Republic) equipped with a system of X-ray microanalysis INCA GSR 450 (Oxford Nanoanalysis, Great Britain). The procedure for detecting GSR particles containing heavy metal compounds, systems of their classification and interpretation of test results are described. The suitability of the methodology for solving forensic problems has been confirmed. The validation procedure consists in assessing the reliability by comparing the test results obtained by experts (A and B) in two laboratories at different times using the same device, and in confirming the competence of experts proceeding from the results of blind tests. A standard sample ENFSI GSR PT 2018 A-03-07 is used. Each of the experts determined the number of particles classified as GSR present in control samples taken in a ballistic laboratory during a full-scale experiment: from the hands of the shooter; from the hands of a person who did not shoot; without microparticles (clean stage of an electron microscope). The reliability of the technique is characterized by the index (probability) of correct results of detecting GSR particles in the standard sample of at least 95.8% and by a small proportion of false results (no more than 5.4%). The competence of the experts is proved by the consistent results of «blind» testing of control full-scale samples, containing and not containing GSR particles obtained in different laboratories. The results of the validation indicate the suitability of the method for obtaining reliable and valid information about the presence of GSR particles on the objects under study.

Two- or three-way observations of the identical cell elements within the same sections by LM, TEM and/or SEM

1978 ◽  
Vol 36 (2) ◽  
pp. 82-83 ◽  
Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Light Microscopy ◽  
Thin Sections ◽  
Transmission Electron ◽  
Identical Cell ◽  
Electron Microscopes ◽  
Scanning Electron

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).

Fibroblasts During Hypertrophic Scar Formation and Resolution

1973 ◽  
Vol 31 ◽  
pp. 428-429
Author(s):  
C. W. Kischer
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Proliferation ◽  
Fine Structure ◽  
Metabolic Activity ◽  
Hypertrophic Scar ◽  
Normal Skin ◽  
Ground Substance ◽  
Hypertrophic Scars ◽  
Scanning Electron

The morphology of the fibroblasts changes markedly as the healing period from burn wounds progresses, through development of the hypertrophic scar, to resolution of the scar by a self-limiting process of maturation or therapeutic resolution. In addition, hypertrophic scars contain an increased cell proliferation largely made up of fibroblasts. This tremendous population of fibroblasts seems congruous with the abundance of collagen and ground substance. The fine structure of these cells should reflect some aspects of the metabolic activity necessary for production of the scar, and might presage the stage of maturation.A comparison of the fine structure of the fibroblasts from normal skin, different scar types, and granulation tissue has been made by transmission (TEM) and scanning electron microscopy (SEM).

Effects of Hypophysectomy on the Fine Structure of Rat Liver Cells

1967 ◽  
Vol 25 ◽  
pp. 156-157
Author(s):  
Robert R. Cardell
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Rat Liver ◽  
Liver Cell ◽  
Anterior Pituitary ◽  
Liver Cells ◽  
Biochemical Studies ◽  
Liver Functions ◽  
Rat Liver Cells ◽  
And Control

Hypophysectomy of the rat renders this animal deficient in the hormones of the anterior pituitary gland, thus causing many primary and secondary hormonal effects on basic liver functions. Biochemical studies of these alterations in the rat liver cell are quite extensive; however, relatively few morphological observations on such cells have been recorded. Because the available biochemical information was derived mostly from disrupted and fractionated liver cells, it seemed desirable to examine the problem with the techniques of electron microscopy in order to see what changes are apparent in the intact liver cell after hypophysectomy. Accordingly, liver cells from rats which had been hypophysectomized 5-120 days before sacrifice were studied. Sham-operated rats served as controls and both hypophysectomized and control rats were fasted 15 hours before sacrifice.

Ultrastructure of the soil fungus, Geomyces pannorus

1984 ◽  
Vol 42 ◽  
pp. 738-739
Author(s):  
J. A. Traquair ◽  
E. G. Kokko
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fine Structure ◽  
Low Temperatures ◽  
Soil Fungus ◽  
Organic Soils ◽  
Anatomical Studies ◽  
Transmission Electron ◽  
Electron Microscopical ◽  
Scanning Electron

With the advent of improved dehydration techniques, scanning electron microscopy has become routine in anatomical studies of fungi. Fine structure of hyphae and spore surfaces has been illustrated for many hyphomycetes, and yet, the ultrastructure of the ubiquitous soil fungus, Geomyces pannorus (Link) Sigler & Carmichael has been neglected. This presentation shows that scanning and transmission electron microscopical data must be correlated in resolving septal structure and conidial release in G. pannorus.Although it is reported to be cellulolytic but not keratinolytic, G. pannorus is found on human skin, animals, birds, mushrooms, dung, roots, and frozen meat in addition to various organic soils. In fact, it readily adapts to growth at low temperatures.

Fine structure and possible functions of the hermaphrodite duct of some pulmonate snails (Mollusca: Gastropoda)

1990 ◽  
Vol 48 (3) ◽  
pp. 68-69
Author(s):  
Alan N. Hodgson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Seminal Vesicle ◽  
Reproductive Biology ◽  
Light Microscope ◽  
Light Microscope Level ◽  
Transmission Electron ◽  
Standard Techniques

The hermaphrodite duct of pulmonate snails connects the ovotestis to the fertilization pouch. The duct is typically divided into three zones; aproximal duct which leaves the ovotestis, the middle duct (seminal vesicle) and the distal ovotestis duct. The seminal vesicle forms the major portion of the duct and is thought to store sperm prior to copulation. In addition the duct may also play a role in sperm maturation and degredation. Although the structure of the seminal vesicle has been described for a number of snails at the light microscope level there appear to be only two descriptions of the ultrastructure of this tissue. Clearly if the role of the hermaphrodite duct in the reproductive biology of pulmonatesis to be understood, knowledge of its fine structure is required.Hermaphrodite ducts, both containing and lacking sperm, of species of the terrestrial pulmonate genera Sphincterochila, Levantina, and Helix and the marine pulmonate genus Siphonaria were prepared for transmission electron microscopy by standard techniques.

Polymers contamination by heavy metal compounds

2002 ◽  
Vol 56 (11) ◽  
pp. 483-488
Author(s):  
Sasa Jovanic ◽  
Dragoslav Stoiljkovic ◽  
Ivanka Popovic
Keyword(s):  
Heavy Metal ◽  
Aqueous Medium ◽  
Metal Compound ◽  
Medium Temperature ◽  
Metal Compounds ◽  
Metal Type ◽  
Copper Manganese ◽  
Increasing Temperature

The contamination of important synthetic (surface unmodified) polymers by various heavy metal compounds (such as copper, manganese and lead) in aqueous medium was investigated in this study. The influence of the pH of the aqueous medium, temperature and metal type on contamination was investigated during a 10 day period. It was found that increasing pH contributed to higher polymer contamination (at higher pH 100 times for copper and up to 400 times for lead), as well as contact with easily penetrable substances. Increasing temperature decreased contamination by the metal compound for PELD and PET which was not the case for PEHD and PR.

scholarly journals A Cellular Reaction to Antibody in Tissue Culture Studied with Electron Microscopy

1959 ◽  
Vol 5 (3) ◽  
pp. 405-410 ◽  
Author(s):  
Harrison Latta
Keyword(s):  
Electron Microscopy ◽  
Tissue Culture ◽  
Endoplasmic Reticulum ◽  
Nuclear Membrane ◽  
Normal Serum ◽  
Butyl Methacrylate ◽  
Heart Cells ◽  
Plasma Clot ◽  
Outer Nuclear Membrane ◽  
Cell Components

The reaction of embryonic chick heart cells grown in tissue culture to specific guinea pig antiserum has been studied with electron microscopy. Heart fragments from chick embryos were cultured with a plasma clot. After being tested with antiserum or normal serum, they were fixed with buffered osmium tetroxide and embedded in butyl methacrylate before removal from the glass culture chamber. Thin cells found by phase microscopy to have reacted were sectioned in a plane parallel to the glass surface on which they had grown. The results confirm and extend observations made previously while the reactions were occurring. The plasma membrane, like that of the red cell, becomes disrupted or less resistant to trauma following the action of antiserum. The membranes of mitochondria and endoplasmic reticulum vesiculate and swell. Before nuclear shrinkage becomes prominent, the outer nuclear membrane separates over a large portion of the nuclear envelope and forms one or more large swollen blebs. Thus, the outer nuclear membrane shows a reactivity similar to endoplasmic reticulum. It is suggested that the various physical and chemical changes observed to follow the action of antibody and complement on fibroblasts may be explained by osmotic pressure differences between various cell components. Some basic similarities to the action of hemolytic agents on red cells are noted.

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