Spontaneous Cataract in Nude Athymic Mice

1977 ◽  
Vol 35 ◽  
pp. 512-513
Author(s):  
Ronald H. Bradley ◽  
R. S. Berk ◽  
L. D. Hazlett
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Nude Mouse ◽  
Cellular Immunity ◽  
Phosphate Buffer ◽  
Osmium Tetroxide ◽  
Athymic Mice ◽  
Transmission Microscopy ◽  
Mouse Lens ◽  
Scanning Electron

The nude mouse is a hairless mutant (homozygous for the mutation nude, nu/nu), which is born lacking a thymus and possesses a severe defect in cellular immunity. Spontaneous unilateral cataractous lesions were noted (during ocular examination using a stereomicroscope at 40X) in 14 of a series of 60 animals (20%). This transmission and scanning microscopic study characterizes the morphology of this cataract and contrasts these data with normal nude mouse lens.All animals were sacrificed by an ether overdose. Eyes were enucleated and immersed in a mixed fixative (1% osmium tetroxide and 6% glutaraldehyde in Sorenson's phosphate buffer pH 7.4 at 0-4°C) for 3 hours, dehydrated in graded ethanols and embedded in Epon-Araldite for transmission microscopy. Specimens for scanning electron microscopy were fixed similarly, dehydrated in graded ethanols, then to graded changes of Freon 113 and ethanol to 100% Freon 113 and critically point dried in a Bomar critical point dryer using Freon 13 as the transition fluid.

Scanning and Transmission Microscopy of Nematocyst Batteries in Epitheliomuscular Cells of Hydra

1971 ◽  
Vol 29 ◽  
pp. 410-411 ◽  
Author(s):  
Jane A. Westfall ◽  
S. Yamataka ◽  
Paul D. Enos
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Osmium Tetroxide ◽  
External Surface ◽  
Three Dimensional ◽  
Surface Structures ◽  
Transmission Microscopy ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Scanning Electron

Scanning electron microscopy (SEM) provides three dimensional details of external surface structures and supplements ultrastructural information provided by transmission electron microscopy (TEM). Animals composed of watery jellylike tissues such as hydras and other coelenterates have not been considered suitable for SEM studies because of the difficulty in preserving such organisms in a normal state. This study demonstrates 1) the successful use of SEM on such tissue, and 2) the unique arrangement of batteries of nematocysts within large epitheliomuscular cells on tentacles of Hydra littoralis.Whole specimens of Hydra were prepared for SEM (Figs. 1 and 2) by the fix, freeze-dry, coat technique of Small and Màrszalek. The specimens were fixed in osmium tetroxide and mercuric chloride, freeze-dried in vacuo on a prechilled 1 Kg brass block, and coated with gold-palladium. Tissues for TEM (Figs. 3 and 4) were fixed in glutaraldehyde followed by osmium tetroxide. Scanning micrographs were taken on a Cambridge Stereoscan Mark II A microscope at 10 KV and transmission micrographs were taken on an RCA EMU 3G microscope (Fig. 3) or on a Hitachi HU 11B microscope (Fig. 4).

The External Morphology of the Eggs of Culex (Culex) saltanensis (Diptera: Culicidae) Under Scanning Electron Microscopy

2020 ◽  
Author(s):  
J R Santos-Mallet ◽  
T D Balthazar ◽  
A A Oliveira ◽  
W A Marques ◽  
A Q Bastos ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Optical Microscopy ◽  
Osmium Tetroxide ◽  
Neotropical Region ◽  
External Morphology ◽  
Metal Supports ◽  
Scanning Electron

Abstract The aim of the present study was to describe the morphology of the eggs of Culex (Culex) saltanensis Dyar that occurs in the Neotropical region. Eggs of the Cx. (Cux.) saltanensis were collected at the Mata Atlântica FIOCRUZ campus, fixed in 1% osmium tetroxide, prepared for mounting on metal supports, observed under a scanning electron microscope, and described morphologically. The eggs had a coniform shape with a length of approximately 0.5 mm (505–510 µm) and a width in the median portion of 117 µm (113–123 µm). Upper portion is lined with tubers of irregular shape and varying sizes (0.64–1.31 µm), located on a cross-linked matrix forming bands observed under optical microscopy. The micropyle is encased in a necklace of approximately 6.6-µm plates arranged in a flower-like shape. Comparing Cx. (Cux.) saltanensis eggs with several species of different genera, important divergent characteristics can be observed. However, this study points to the need for new descriptions of eggs of species belonging to the same subgenus in order to analyze if there will be differences between them. Culex (Cux.) saltanensis eggs have particular characteristics not observed in eggs of other Culicidae genera.

Field Emission Scanning Electron Microscopy Of Mouse Cerebellar Synaptic Contacts

2000 ◽  
Vol 6 (S2) ◽  
pp. 844-845
Author(s):  
O.J. Castejón ◽  
R. P. Apkarian ◽  
H. V. Castejón
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Field Emission ◽  
Cerebellar Cortex ◽  
Osmium Tetroxide ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Solution Ph ◽  
Osmium Tetroxide Solution ◽  
Scanning Electron

Samples of albino mice cerebellar cortex were processed by the cryofracture method for scanning electron microscopy and examined with the field emission scanning electron microscope (FESEM). Albino mouse cerebellar cortex was excised, cut into 1-2 mm slices and inmersed in 4% glutaraldehyde in O. l M phosphate buffer solution, pH 7.4, for 24h at 4°C; and postfixed for 1 h in a similarly buffered 1% osmium tetroxide solution. Specimens were dehydrated in a graded serie of ethanol (30, 50, 70, 80, 90 2x100%) prior to wrapping individual tissue pieces in preformed absolute ethanol filled parafilm cryofracture packets. Rapid freezing of packets was performed by plunging into LN2. First, the packet was transferred from the LN2 storage vessel with LNT chilled forceps in order to avoid themial damage. Secondly, the cooled fracture blade was removed from the LN2, the packet was orientated under the blade, and immediately struck with a heavy tool.

Microcysys in the Posteroventral Cochlear Nucleus of the Gerbil by Scanning Electron Microscopy

1997 ◽  
Vol 3 (S2) ◽  
pp. 257-258
Author(s):  
S.M. Yu ◽  
C.I. Lee
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cochlear Nucleus ◽  
Phosphate Buffer ◽  
Neurodegenerative Disorder ◽  
Meriones Unguiculatus ◽  
Anteroventral Cochlear Nucleus ◽  
Critical Point Drying ◽  
Ethanol Series ◽  
Scanning Electron

Microcysts are most evident in the posteroventral and anteroventral cochlear nucleus (PVCN & AVCN) of the gerbil. They are reported as a neurodegenerative disorder or spongioform degeneration or a dynamic process related to the degree of auditory stimulation in the cochlear nucleus of the gerbil. Little information is avalable on the origin and formation of microcysts in the cochlear nucleus of the gerbil. The aim of this study was to investigate the internal morphologic changes of microcysts in the gerbil PVCN during postnatal development by scanning electron microscopy.The mongolian gerbil, Meriones unguiculatus, were sacrificed by cardiac perfusion of a saline nitrite flush, followed by a 3% glutaraldehyde in 0.1M phosphate buffer. After fixation the brain were washed in 0.1M phosphate buffer ,embedded in 5% agar, vibratome-sliced through the cochlear nucleus, and then postfixed in the 1% osmium tetroxide in 0.1M phosphate buffer for one hour. The sectioned tissues were dehydrated in a graded ethanol series to absolute ethanol and transferred to liquid carbon dioxide for critical point drying.

scholarly journals Preparation, Evaluation & Optimization of Nanoparticles Composed of Pyridostigmine

2021 ◽  
Vol 9 (11) ◽  
pp. 1422-1438
Author(s):  
Niwash Kumar
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Controlled Release ◽  
Drug Release ◽  
Zeta Potential ◽  
Phosphate Buffer ◽  
Polydispersity Index ◽  
Nanoparticle Formulation ◽  
Scanning Electron

Abstract: The purpose of this study was to prepare Pyridostigmine nanoparticles for control release of Pyridostigmine to improve the oral bioavailability, enhance the solubility and dissolution rate by decreasing particle size of drug. Infrared spectroscopic studies confirmed that there was no interaction between drug and polymers. The controlled release Pyridostigmine nanoparticles were prepared by Solvent evaporation by using Ethyl cellulose, Chitosan & HPMC K100 at different ratios. The production yield of the formulated controlled release nanoparticles (F1 to F16) in the range of 76.11 % to 83.58 %. The drug content of the formulated controlled release nanoparticles (F1 to F16) in the range of 82.56 %to 98.20%. The Theoretical loading of the formulated controlled release nanoparticles (F1- F16) in the range of 24.43 % to 64.24%. The entrapment efficiency increased with increasing the concentration of polymers and the formulations containing chitosan nanoparticles F6 (1:2) showed better entrapment (90.94%) among all formulation. The solubility of selected formulation (F6) in 0.2 M Phosphate buffer pH 6.8 increased when compared to pure drug. Particle size distribution was determined by Malvern zeta size, the size range for produced nanoparticles in the range of 200 nm to 400 nm. The Polydispersity index of selected nanoparticle formulation (F6) was indicated a narrow range and a homogeneous size distribution of particles. The in vitro dissolution study was carried out in 0. 2N PBS for 2 hours and phosphate buffer pH 6.8 for 10 hours. The formulations shows controlled release of drug up to 12 hrs and all formulations showed more than 75% of drug release. The release kinetics showed that the formulations were complies with Zero order kinetics followed by diffusion controlled mechanism. The best formulation F6 was evaluated by infrared spectroscopy, particle size, Polydispersity index & zeta potential and Scanning Electron microscopy. Best formulation of nanoparticles shown the extent of drug release was found to be F6 (96.93%) in 12 hrs. SEM studies confirmed the morphology of the nanoparticle formulation. Keywords: Polydispersity index, Zeta potential, Scanning Electron microscopy, Pyridostigmine

A technique for preparing Beauveria spp. for scanning electron microscopy

1980 ◽  
Vol 58 (15) ◽  
pp. 1700-1703 ◽  
Author(s):  
E. C. Quattlebaum ◽  
G. R. Carner
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Freeze Drying ◽  
Osmium Tetroxide ◽  
Air Drying ◽  
Preparation Methods ◽  
Critical Point Drying ◽  
Scanning Electron

Vapor fixation for 96 h with 1% osmium tetroxide (OsO4) and 3–4 days air drying produced distortion-free specimens of Beauveria spp. for examination with the scanning electron microscope. A combination of 4 h OsO4 vapor fixation and freeze-drying also reduced disruption satisfactorily but specimens were not as well preserved as with the first method. Preparation methods that were ineffective in preventing collapse of hydrophilic structures were Cling Free® sprayed on specimens prior to examination, freeze-drying, critical-point drying (of unfixed material), and vapor fixation with glutaraldehyde.

Fixation and conductive staining by tannin-RuO4 for transmission and scanning electron microscopy

1990 ◽  
Vol 48 (3) ◽  
pp. 24-25
Author(s):  
Gen Takahashi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Thin Section ◽  
Tannic Acid ◽  
Osmium Tetroxide ◽  
Glutaraldehyde Fixation ◽  
Ruthenium Tetroxide ◽  
Cellular Ultrastructure ◽  
Scanning Electron

Ruthenium tetroxide(RuO4) was first used as a stain in histology by Ranvier in 1887. Its use in TEM as a fixative or stain was reported by Gaylarde et al. However,the preservation of the cellular ultrastructure was very poor after RuO4 fixation alone, because RuO4 is a far more vigorous oxidant than osmium tetroxide. Peltari et al reported that a preceeding glutaraldehyde fixation helped to stabilize the ultrastructure, although the penetration of RuO4 into the tissue was poor.In the present study, RuO4 has been found to be a useful fixative and staining reagent with the prerequisite of using RuO4 as a postfixative after prefixation with tannic acid (TA)-glutaraldehyde(GL) for thin-section TEM(TA-RuO4 method) or after preceeding osmication followed by TA mordanting for non-coating SEM(OsO4-TA-RuO4 method).TA-RuO4 method for thin-section TEM

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