scholarly journals A novel cytochemical marker for liposome decomposition in lysosomes.

1983 ◽  
Vol 31 (3) ◽  
pp. 404-410 ◽  
Author(s):  
S C Ho ◽  
L Huang
Keyword(s):  
Electron Microscopy ◽  
Enzymatic Reaction ◽  
Chinese Hamster ◽  
Electron Dense Deposit ◽  
Transmission Electron ◽  
Dense Deposit ◽  
Condensed Product ◽  
Dense Deposits ◽  
Indigo Blue ◽  
Cytochemical Marker

The endocytosis of large unilamellar liposomes composed of phosphatidylcholine by the cultured Chinese hamster V-79 cells is demonstrated with electron microscopy cytochemistry. A novel cytochemical marker, 5-Br,4-Cl,3-indolylphosphate (BCIP) is used. This marker is a soluble and colorless substrate for the lysosomal acid phosphatase and can be readily entrapped in liposomes. The product of the enzymatic reaction, 5-Br,4-Cl,3-hydroxy indole, rapidly self-condenses and becomes an insoluble derivative of indigo blue. In thin section transmission electron microscopy, the condensed product appears as electron-dense deposits in the lysosomes. Since the electron-dense deposit only appears when the endocytosed liposomes are delivered to the lysosomes as the result of phagosome-lysosome fusion, this marker provides a unique cytochemical means to reveal those liposomes that are lysosomotropic and are actually decomposed within the lysosomes. No electron-dense deposits are found in the liposome-treated cells in the presence of chloroquine, or a combination of NaN3 and deoxyglucose. As a comparison, we have also used horseradish peroxidase entrapped in liposomes to confirm the endocytic uptake of liposomes. Using a radioactive marker, 125I-labeled lysozyme, entrapped in liposomes, it is shown that about 20-30% of liposome uptake by V-79 cells is due to endocytosis.

The Prevalence of Mesangial Electron-Dense Deposits in PLA2R-Positive Membranous Nephropathy

Nephron ◽  
2021 ◽  
pp. 1-5
Author(s):  
Gabriel Giannini ◽  
Lois J. Arend
Keyword(s):  
Electron Microscopy ◽  
Nephrotic Syndrome ◽  
Membranous Nephropathy ◽  
Immunofluorescence Microscopy ◽  
Common Cause ◽  
Electron Dense Deposit ◽  
Dense Deposit ◽  
Phospholipase A2 Receptor ◽  
Dense Deposits ◽  
Negative Biopsies

<b><i>Introduction:</i></b> Membranous nephropathy (MN) is a common cause of nephrotic syndrome in adults and can be primary or secondary. The antigenic target of antibodies in 70% of primary cases is phospholipase A2 receptor (PLA2R). The presence or absence of mesangial electron-dense deposits has been used to distinguish between primary and secondary MN. Mesangial deposits suggest MN due to lupus, infection, or other causes, though they are reported to occur in approximately 10% of primary MN. Staining for PLA2R is now frequently used for confirming a diagnosis of primary MN. If mesangial deposits predict a secondary cause, they should be more frequent in PLA2R-negative biopsies. <b><i>Methods:</i></b> A review of institutional kidney biopsies between March 2017 and June 2020 identified all cases of MN. Cases with a diagnosis of lupus or near “full-house” staining by immunofluorescence microscopy (IF) were excluded. Light microscopy, IF, and electron microscopy (EM) were performed. PLA2R staining was performed by IF. EM for all cases was reviewed and electron-dense deposit location, distribution, and size were determined. <b><i>Results:</i></b> Ninety-three cases of MN were identified, of which 86 had both PLA2R staining and EM performed. Of these, 51 cases (59%) were positive for PLA2R and 35 (41%) were negative. Mesangial electron-dense deposits were present in 22 (25.6%) of the 86 cases, including 27.5% (14/51) of PLA2R-positive cases and 22.8% (8/35) of PLA2R-negative cases. No difference was seen in size or distribution of deposits, or other features considered suggestive of secondary MN. <b><i>Conclusion:</i></b> PLA2R-negative cases were not more likely to have mesangial deposits than PLA2R-positive cases. Mesangial deposits should not be used as an indicator of secondary MN.

A MORPHOLOGICAL APPROACH TO THE MECHANISMS OF RISTOCETIN INDUCED PLATELET AGGLUTINATION(RIPA)

1987 ◽  
Author(s):  
G Escolar ◽  
J Monteagudo ◽  
N Villamor ◽  
M Garrido ◽  
R Castillo
Keyword(s):  
Electron Microscopy ◽  
Monoclonal Antibody ◽  
Platelet Rich Plasma ◽  
Human Platelets ◽  
Complex Interaction ◽  
Electron Dense Deposit ◽  
Transmission Electron ◽  
Dense Deposit ◽  
Morphological Approach ◽  
Adhesive Proteins

Changes in the morphology of human platelets induced by Ristocetin (RIPA) have been analyzed at ultraestructural level by means of a tannine acid procedure. Studies were completed with aggregation and binding experiments. Modificationsof these tests induced by apyrase,a monoclonal antibody (Mab) to GPIIb/IIIa and EDTA were also investigated.Transmission electron microscopy reveals that ristocetin precipitates adhesive proteins on plateletmembrane. An electron-dense deposit was noticeable within 20 secondsafter ristocetin was added. When experiments were carried out in theaggregometer cuvette under stirring, groups of platelets become activated, change shape, and finally aggregate releasing part of their content. The morphology of aggregates did not differ from those formed in the presence of ADP.Aggregation studies demonstrated that a Mab to GPIIb/IIIa modifies the extent and the rate of the aggregation curve when RIPA was performed in citrated platelet rich plasma (c-PRP). Apyrase modified the extent but not the slope of the curve. Neither the antibody nor apyrase modified RIPA when it was performed in PRP obtained in presence of EDTA. Binding experiments confirmed that I-vWF bound to platelets in presence of ristocetin was not modified by apyrase or anti-GPIIb/IIIa Mab. All these facts together suggest that RIPA,when performed in c-PRP besides reflecting the interaction of GPI with vWF, is also testing other mechanisms of the platelet function including exposure of GPIIb/IIIa complex, interaction of fibrinogen with this glycoprotein, and the contribution of the release reaction.

Adhesion of Phytophthora palmivora zoospores: electron microscopy of cell attachment and cyst wall fibril formation

1975 ◽  
Vol 18 (1) ◽  
pp. 123-132
Author(s):  
V.O. Sing ◽  
S. Bartnicki-Garcia
Keyword(s):  
Electron Microscopy ◽  
Cell Adhesion ◽  
Cyst Wall ◽  
Cell Attachment ◽  
Sodium Dodecyl ◽  
Film Surface ◽  
Phytophthora Palmivora ◽  
Thin Sections ◽  
Electron Dense Deposit ◽  
Dense Deposit

Zoospores of Phytophthora palmivora adhered to a plastic film surface were examined by electron microscopy. Three stages of adhesion were compared: (1) non-adhesive, unencysted zoospores, (2) adhered incipient cysts, and (3) adhered mature cysts. Thin sections of incipient cysts revealed cells attached to the film surface through the partially discharged contents of the so-called peripheral vesicles; this seems to be the first step in cell adhesion. In mature cysts, the adhesive appeared to have been compacted into an electron-dense deposit binding the cyst wall to the plastic surface. The adhesion zone was also examined in face view after lysing attached incipient cysts with sodium dodecyl sulphate. Cyst wall microfibrils were seen together with an amorphous substance (presumably the adhesive material). The microfibrils were in various stages of formation. Seemingly, adhesion and microfibril formation take place concurrently. The possibility was considered that the material contained in the peripheral vesicles serves in both cell adhesion and microfibril elaboration.

Cytopathological changes induced by potato spindle tuber viroid in Scopolia sinensis

1981 ◽  
Vol 59 (5) ◽  
pp. 677-682 ◽  
Author(s):  
Y. C. Paliwal ◽  
R. P. Singh
Keyword(s):  
Potato Spindle Tuber Viroid ◽  
Infected Tissue ◽  
Cell Organelles ◽  
Electron Dense Deposit ◽  
Dense Bodies ◽  
Dense Deposit ◽  
Dense Deposits ◽  
Local Lesions ◽  
Extensive Cell ◽  
In Cells

The mesophyll parenchyma of Scopolia sinensis Hemsl. leaves infected with potato spindle tuber viroid (PSTV) was examined for cytopathological changes. Cells of the systemically infected tissue showed a proliferation of cytoplasmic membranes in the form of sheets or vesicles and generally these membranes and the tonoplast were studded with electron-dense deposits. About 47% of the cells examined contained amorphous electron-dense inclusions in their vacuoles but about 3% of the healthy leaf cells also contained a few such inclusions. The lumen of many mature cells contained small spherical to oval electron-dense bodies interspersed with fibrils. In cells adjoining the local lesions on inoculated leaves, electron-dense bodies were not found and membrane deposits were rare. However, the amorphous inclusions occurred in 52% of these cells examined. Extensive cell wall deposits containing flattened tubules and vesicles were common in cells adjoining local lesions. Only smaller, localized wall deposits were found in cells of the systemically infected tissue and in some cells adjoining local lesions. Cell organelles were generally unaffected in systemically infected tissue except that mitochondria often contained vacuoles filled with an electron-dense deposit. However, degenerating chloroplasts and mitochondria were common in cells adjoining local lesions.

scholarly journals An electron microscopic histochemical and analytical X-ray microprobe study of calcification in Bruch's membrane from human eyes.

1981 ◽  
Vol 29 (5) ◽  
pp. 601-608 ◽  
Author(s):  
W L Davis ◽  
R G Jones ◽  
H K Hagler
Keyword(s):  
Electron Microscopy ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Phosphotungstic Acid ◽  
Electron Microscopic ◽  
X Ray ◽  
Transmission Electron ◽  
Dense Deposits ◽  
Calcium And Phosphorus ◽  
Human Eyes

Transmission electron microscopy, electron microprobe analysis, high temperature microincineration, and electron microscopic histochemical procedures were used to study the electron-dense deposits characteristic of the macular aspect of aged human eyes. These inorganic deposits were rich in calcium and phosphorus and selectively removed by flotation on formic acid. The amorphous decalcified masses showed a significant sulfur peak and were readily stained with acidic phosphotungstic acid. The latter observations are indicative of the presence of organic matrical proteoglycan. Such data may be a further indication that proteoglycans are retained at sites of calcification.

Techniques for Transmission Electron Microscopy of Fiber-Matrix Interfaces in Aluminum Alloy-Boron Composites by Ion Erosio

1971 ◽  
Vol 29 ◽  
pp. 204-205
Author(s):  
G. G. Shaw
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloy ◽  
Electron Beam ◽  
Pure Aluminum ◽  
Ion Milling ◽  
Transmission Electron ◽  
Fiber Matrix ◽  
Ion Erosion ◽  
Row Of Fibers

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.

Direct Observation of Heat Exchanger Deposits by Cross Sectioning

1967 ◽  
Vol 25 ◽  
pp. 364-365
Author(s):  
R. W. Anderson ◽  
D. L. Senecal
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heat Exchanger ◽  
Direct Observation ◽  
Cross Sections ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Flowing Water ◽  
Transmission Electron ◽  
Deposit Layer

A problem was presented to observe the packing densities of deposits of sub-micron corrosion product particles. The deposits were 5-100 mils thick and had formed on the inside surfaces of 3/8 inch diameter Zircaloy-2 heat exchanger tubes. The particles were iron oxides deposited from flowing water and consequently were only weakly bonded. Particular care was required during handling to preserve the original formations of the deposits. The specimen preparation method described below allowed direct observation of cross sections of the deposit layers by transmission electron microscopy.The specimens were short sections of the tubes (about 3 inches long) that were carefully cut from the systems. The insides of the tube sections were first coated with a thin layer of a fluid epoxy resin by dipping. This coating served to impregnate the deposit layer as well as to protect the layer if subsequent handling were required.

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

Ultrastructural Analysis of the Salivary Glands of Gromphadorhina Portentosa (Schaum)

1977 ◽  
Vol 35 ◽  
pp. 638-639
Author(s):  
P.J. Dailey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Salivary Glands ◽  
Secretory Vesicles ◽  
The Past ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
Gromphadorhina Portentosa ◽  
Scanning Electron ◽  
Topographical Relief

The structure of insect salivary glands has been extensively investigated during the past decade; however, none have attempted scanning electron microscopy (SEM) in ultrastructural examinations of these secretory organs. This study correlates fine structure by means of SEM cryofractography with that of thin-sectioned epoxy embedded material observed by means of transmission electron microscopy (TEM).Salivary glands of Gromphadorhina portentosa were excised and immediately submerged in cold (4°C) paraformaldehyde-glutaraldehyde fixative1 for 2 hr, washed and post-fixed in 1 per cent 0s04 in phosphosphate buffer (4°C for 2 hr). After ethanolic dehydration half of the samples were embedded in Epon 812 for TEM and half cryofractured and subsequently critical point dried for SEM. Dried specimens were mounted on aluminum stubs and coated with approximately 150 Å of gold in a cold sputtering apparatus.Figure 1 shows a cryofractured plane through a salivary acinus revealing topographical relief of secretory vesicles.

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).

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