scholarly journals Addition of phosphotungstic acid to ethanol for dehydration improves both the ultrastructure and antigenicity of pituitary tissue embedded in LR White acrylic resin

2005 ◽  
Vol 68 (5) ◽  
pp. 337-347 ◽  
Author(s):  
Yuko Sakai ◽  
Masahiro Hosaka ◽  
Yoshiki Hira ◽  
Tsuyoshi Watanabe
Author(s):  
B. L. Giammara ◽  
A. O. Rose ◽  
J. S. Hanker

Microwave embedment methods have been developed for epoxy and polyester resins. Because the thick yeast cell wall is known to inhibit penetration by many embedding media, we wished to use an embedding agent exhibiting favorable properties of hydrophilicity and low viscosity. The complex requirement for low temperature and curing using UV irradiation with the polymer Lowicryl, and recent advantages described for yeast using LR White, made the latter polymer a good candidate for our studies.Saccharomyces cerevisiae was grown at 30°C in selective medium to an OD640 = 1.0. A modification of the procedure of Tuinen and Riezman was used to fix the cells. Briefly, the cells were washed three times with Sorenson's buffer, pH 7.3, and fixed as a suspension in 3% paraformaldehyde, 0.25% glutaraldehyde in Sorenson's for 2 hours at room temperature. The cells were again washed three times followed by incubation in 1 % sodium meta-periodate at room temperature for one hour.


2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 255-257
Author(s):  
P. Kudláčková ◽  
M. Zouhar ◽  
P. Ryšánek

Beet soilborne pomovirus (BSBV) was observed both in the sap and in tissues from local lesions on Chenopodium quinoa leaves after their embedding into acrylic resin LR White. Immunocapturing with polyclonal antibodies was used to enhance number of particles on grids and immunolabelling by colloidal gold was used for better visibility of virus particles in tissues. BSBV has rod-like particles of various length and it forms inclusions of several particles adhering side to side each to another.


Author(s):  
Edward C. Yeung ◽  
Bing Quan Huang
Keyword(s):  

Author(s):  
E. N. Albert

Silver tetraphenylporphine sulfonate (Ag-TPPS) was synthesized in this laboratory and used as an electron dense stain for elastic tissue (Fig 1). The procedures for the synthesis of tetraphenylporphine sulfonate and the staining method for mature elastic tissue have been described previously.The fine structure of developing elastic tissue was observed in fetal and new born rat aorta using tetraphenylporphine sulfonate, phosphotungstic acid, uranyl acetate and lead citrate. The newly forming elastica consisted of two morphologically distinct components. These were a central amorphous and a peripheral fibrous. The ratio of the central amorphous and the peripheral fibrillar portion changed in favor of the former with increasing age.It was also observed that the staining properties of the two components were entirely different. The peripheral fibrous component stained with uranyl acetate and/or lead citrate while the central amorphous portion demonstrated no affinity for these stains. On the other hand, the central amorphous portion of developing elastic fibers stained vigorously with silver tetraphenylporphine sulfonate, while the fibrillar part did not (compare figs 2, 3, 4). Based upon the above observations it is proposed that developing elastica consists of two components that are morphologically and chemically different.


Author(s):  
J. Quatacker ◽  
W. De Potter

Mucopolysaccharides have been demonstrated biochemically in catecholamine-containing subcellular particles in different rat, cat and ox tissues. As catecholamine-containing granules seem to arise from the Golgi apparatus and some also from the axoplasmic reticulum we examined wether carbohydrate macromolecules could be detected in the small and large dense core vesicles and in structures related to them. To this purpose superior cervical ganglia and irises from rabbit and cat and coeliac ganglia and their axons from dog were subjected to the chromaffin reaction to show the distribution of catecholamine-containing granules. Some material was also embedded in glycolmethacrylate (GMA) and stained with phosphotungstic acid (PTA) at low pH for the detection of carbohydrate macromolecules.The chromaffin reaction in the perikarya reveals mainly large dense core vesicles, but in the axon hillock, the axons and the terminals, the small dense core vesicles are more prominent. In the axons the small granules are sometimes seen inside a reticular network (fig. 1).


Author(s):  
Julie A. Martini ◽  
Robert H. Doremus

Tracy and Doremus have demonstrated chemical bonding between bone and hydroxylapatite with transmission electron microscopy. Now researchers ponder how to improve upon this bond in turn improving the life expectancy and biocompatibility of implantable orthopedic devices.This report focuses on a study of the- chemical influences on the interfacial integrity and strength. Pure hydroxylapatite (HAP), magnesium doped HAP, strontium doped HAP, bioglass and medical grade titanium cylinders were implanted into the tibial cortices of New Zealand white rabbits. After 12 weeks, the implants were retrieved for a scanning electron microscopy study coupled with energy dispersive spectroscopy.Following sacrifice and careful retrieval, the samples were dehydrated through a graduated series starting with 50% ethanol and continuing through 60, 70, 80, 90, 95, and 100% ethanol over a period of two days. The samples were embedded in LR White. Again a graduated series was used with solutions of 50, 75 and 100% LR White diluted in ethanol.


Author(s):  
César D. Fermin ◽  
Dale Martin

Otoconia of higher vertebrates are interesting biological crystals that display the diffraction patterns of perfect crystals (e.g., calcite for birds and mammal) when intact, but fail to produce a regular crystallographic pattern when fixed. Image processing of the fixed crystal matrix, which resembles the organic templates of teeth and bone, failed to clarify a paradox of biomineralization described by Mann. Recently, we suggested that inner ear otoconia crystals contain growth plates that run in different directions, and that the arrangement of the plates may contribute to the turning angles seen at the hexagonal faces of the crystals.Using image processing algorithms described earlier, and Fourier Transform function (2FFT) of BioScan Optimas®, we evaluated the patterns in the packing of the otoconia fibrils of newly hatched chicks (Gallus domesticus) inner ears. Animals were fixed in situ by perfusion of 1% phosphotungstic acid (PTA) at room temperature through the left ventricle, after intraperitoneal Nembutal (35mg/Kg) deep anesthesia. Negatives were made with a Hitachi H-7100 TEM at 50K-400K magnifications. The negatives were then placed on a light box, where images were filtered and transferred to a 35 mm camera as described.


Author(s):  
C. D. Humphrey ◽  
C.S. Goldsmith ◽  
L. Elliott ◽  
S.R. Zaki

An outbreak of unexplained acute pulmonary syndrome with high fatality was recognized in the spring of 1993 in the southwestern United States. The cause of the illness was quickly identified serologically and genetically as a hantavirus and the disease was named hantavirus pulmonary syndrome (HPS). Recently, the virus was isolated from deer mice which had been trapped near the homes of HPS patients, and cultivated in Vero E6 cells. We identified the cultivated virus by negative-stain direct and colloidal gold immune electron microscopy (EM).Virus was extracted, clarified, and concentrated from unfixed and 0.25% glutaraldehyde fixed supernatant fluids of infected Vero E6 cells by a procedure described previously. Concentrated virus suspensions tested by direct EM were applied to glow-discharge treated formvar-carbon filmed grids, blotted, and stained with 0.5% uranyl acetate (UA) or with 2% phosphotungstic acid (PTA) pH 6.5. Virus suspensions for immune colloidal gold identification were adsorbed similarly to filmed grids but incubated for 1 hr on drops of 1:50 diluted monoclonal antibody to Prospect Hill virus nucleoprotein or with 1:50 diluted sera from HPS virus infected deer mice.


Author(s):  
Marie-Thérèse Nicolas

An alternative to aqueous chemical fixation consists in immobilizing physically the specimen by freezing it as fast as possible without using any cryoprotectant. This Fast Freeze Fixation (FFF) followed by Freeze Substitution (FS) avoids osmotic artefacts due to the slow penetration of liquid chemical fixative. Associated with Immuno-Gold labeling (IGS), FFF-FS allows a more precise localization of antigens.Using the bioluminescent bacteria Vibrio harveyi, a comparison of IGS with an antibody directed against its luciferase (enzyme of the luminescent reaction) has been done after liquid chemical fixation versus FFFFS. This later technique, beside an expected improvement of the ultrastructure always shows a better preservation of antigenicity and a lower background. In the case of FFF-FS technique (Figure 3):–labeling in acrylic resin (LRWhite) is 2 to 4 fold more intense than in epoxy resin (Epon),–but the ultrastructure is always better in Epon.–but the ultrastructure is always better in Epon.–The addition of fixatives in the substitution medium, results in a decrease of labeling which is more important in the case of a mixture of fixatives than with osmium tetroxide alone; with one exception: the substitution with glutaraldehyde which produces a dramatic increase in the density of the labeling but also, at the same time, a swelling of the cells of about 30%.


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