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PubMed1992

Golgi method without osmium tetroxide for the study of the central nervous system.

A variant Golgi technique was developed that consisted of substituting osmium tetroxide with formaldehyde as the initial fixative in intracardiac perfusion, along with the addition of glacial acetic acid to the chromating fluid. This procedure avoids disposal of dangerous waste substances into the environment. Other advantages include 1) reduction of cost, danger to lab workers, and risk of disruption of the tissue slices during their handling by eliminating the osmium tetroxide, 2) clear tissue background, 3) greater quantity of impregnated neurons than in the classical procedure, with distinct morphological details easily identified even in gross sections and 4) reduction in processing time.

Animals↗
PubMed1995

Osmium tetroxide-potassium ferrocyanide intensification of a diaminobenzidine product obtained by photoconversion of a fluorescent label: a study of human neutrophil granules.

A diaminobenzidine posttreatment employing osmium tetroxide and potassium ferrocyanide was successfully used to intensify the diaminobenzidine stain formed by photoconversion of immunofluorescent labelling. Lactoferrin labelled granules became visible following the photoconversion process. Adequate diaminobenzidine staining was obtained after irradiating the cytospin preparations with ultraviolet light for 30-40 min. The diaminobenzidine stain had advantages over the fluorescent stain owing to its greater stability, greater density, and ability to be intensified. The enhancement procedure intensified both the color and density of the diaminobenzidine product. Consequently, shorter irradiation times could be used. Osmium tetroxide solutions of 3-4% increased the intensity with minimal background staining. Ultrastructural immunogold cytochemistry on ultrathin sections confirmed the existence of the lactoferrin labelled structures observed by light microscopy of cytospin preparations indicating that these were secondary granules. The photomicroscopy procedures used in this study were simple to perform and could be applied to studies of other cellular antigens prior to using immunoultramicroscopy.

3,3'-Diaminobenzidine↗
PubMed1977

Schistosoma mansoni tegumental appendages: scanning microscopy following thiocarbohydrazide-osmium preparation.

Scanning photographs of the surface of normal adult male and female Schistosoma mansoni are given. The specimens were prepared using a thiocarbohydrazide technique which facilitates the binding of osmium. The resultant deep penetration of osmium preserves surface detail for electron reflection. The schistosomal tegument is characterized by a variety of surface bosses and spines. The function of certain of these is thought to be tactile or as chemoreceptors. Numerous tegumental pores surrounding setae in surface tubercles are shown. Clefts in the inner aspect of the gynecophoral canal are also seen. The excretory pore in both male and female is shown, along with a cluster of receptors at the terminus of the gynecophoral groove. Such grouped receptors may function to indicate position of the worm in copula.

Animals↗
PubMed1992

Effects and distribution of intravitreally or subretinally injected silicone oil identified in rabbit retina using osmium tetroxide method.

Silicone oil was injected into the eyes of 28 rabbits. Utilizing the specific affinity of osmium tetroxide for lipids, the pathological features and histochemical localization of silicone oil within the retina were studied. This osmium tetroxide technique makes it possible to identify the presence of silicone oil particles in the ocular tissues. It was demonstrated that in eyes with silicone oil injected into the vitreous cavity or subretinal space, silicone oil was detected in the inner retinal layer and in phagocytes in the vitreous cavity but not in the outer retinal layer, retinal pigment epithelium and choroid. In addition, prominent subretinal and epiretinal proliferation with abundant phagocytes containing silicone oil particles were noted in the eyes with subretinal injection of silicone oil through an artificial retinal break. This study suggests that when injected subretinally silicone oil induces excessive subretinal and epiretinal proliferation.

Animals↗
PubMed2003

Comparative effect of osmium tetroxide and ruthenium tetroxide on Penicillium sp. hyphae and Saccharomyces cerevisiae fungal cell wall ultrastructure.

The fungal cell wall viewed through the electron microscope appears transparent when fixed by the conventional osmium tetroxide method. However, ruthenium tetroxide post-fixing has revealed new details in the ultrastructure of Penicillium sp. hyphae and Saccharomyces cerevisiae yeast. Most significant was the demonstration of two or three opaque diverse electron dense layers on the cell wall of each species. Two additional features were detected. Penicillium septa presented a three-layered appearance and budding S. cerevisiae yeast cell walls showed inner filiform cell wall protrusions into the cytoplasm. The combined use of osmium tetroxide and ruthenium tetroxide is recommended for post-fixing in electron microscopy studies of fungi.

Cell Wall↗
PubMed1991

A new visualization principle of cerium phosphate reaction product of phosphatases in cryotome sections for light microscopy--the cerium-oxalate-osmium-silver (Ce-Ox-Os-Ag) method.

A new visualization principle for the detection of cerium phosphate reaction product of phosphatases in light microscopy is described. The new mode is based on the conversion of cerium phosphate into cerium oxalate. The latter is able to react with OsO4. In this way osmium black is formed, staining enzymatic activity sites grey or greyish-black. Utilizing the argyrophilia of osmium black, the staining contrast could be remarkably intensified by posttreatment with Ag-proteinate (Ce-Ox-Os-Ag procedure). This procedure is of similar sensitiveness in comparison to the DAB-Ni method, proposed earlier. The advantages are a very pale background staining and a complete suppression of the cerophilia. Moreover, it substitutes to DAB, a probable potent carcinogen. The method is time-saving when the processing of the reactions was stimulated in a microwave oven.

Animals↗
PubMed1991

Osmium tetroxide reactivity of DNA bases in nucleotide sequencing and probing of DNA structure.

Osmium tetroxide, 2,2'-bipyridine (Os,bipy) has been widely applied as a probe of the DNA structure. To obtain information about reactivity of DNA bases toward this probe synthetic homopolynucleotides poly(dT), poly(dC), poly(dG) and poly(dA) were treated with Os,bipy and the content of modified bases measured by stripping voltammetry and absorption spectrophotometry. After 20 hours' treatment strong modification of poly(dT) and poly(dC) and weak modification of poly(dG) were observed, while no modification was detected in poly(dA). At short incubation times under conditions close to those usually used in probing the DNA structure the extent of poly(dT) modification was more than 10 times higher than that of poly(dC). Thus, in single-stranded DNA Os,bipy reacts with T much greater than C and G. Due to the fast reaction of thymines with Os,bipy (and osmium tetroxide, pyridine) these chemicals can be applied in Maxam-Gilbert nucleotide sequencing as agents specific for thymines in single-stranded DNA.

2,2'-Dipyridyl↗
PubMed1987

Morphological study of the transverse-axial tubular system (TAxTS) in rat heart using ferrocyanide-osmium method and thick sectioning.

The structure of the transverse-axial tubular system (TAxTS) in ventricular and atrial myocytes of the rat heart was investigated by examining thick (as much as 0.2 micron) and thin sections stained by the ferrocyanide-osmium method. Ventricular myocytes contain longitudinally and transversely oriented tubules which represent invaginations of the plasma membranes and form orderly latticeworks. These tubules are irregular in diameter and course tortuously. Dilated, triangular cisterns are often seen at the points of interconnections between longitudinal and transverse elements. The junctional sarcoplasmic reticulum forms 'couplings' with both transversely and longitudinally oriented TAxTS tubules, and a large proportion of the surface area of the TAxTS tubules is involved in such couplings. In atrial myocytes, the TAxTS tubules are poorly developed and pleomorphic, often with a beaded appearance, and show an irregular distribution from one cell to another and from one area to another within a given cell. The osmium-ferrocyanide stain reveals the TAxTS to be much more extensive than is evident from examination of routinely stained preparations.

Animals↗
PubMed1987

Use of osmium etching procedures for studying the ultrastructure of isolated rat islets of Langerhans.

Variants of the osmium etching procedure, described by Tanaka et al. for the demonstration of the structure of organelles by scanning electron microscopy, have been utilized in studies of isolated rat islets of Langerhans. Use of a preliminary glutaraldehyde fixation followed by the osmium etching procedure originally described, allowed effective removal of the cytoplasmic ground substance, as demonstrated by transmission electron microscopy. High resolution scanning electron microscopy of similar preparations permitted studies of the interaction of cytoskeletal elements with individual organelles. In particular, direct interactions of insulin storage granules with cytoskeletal elements were clearly evident.

Animals↗
PubMed1987

Morphological aspects and observations about the permeability of the rat mesentery to the osmium-amine.

In a previous work we felt that many authors were interested in observing the permeability and structure of the mesentery employing many techniques and analysing the material from different points of view. Our collaboration, at that time, was limited to the study of the permeability of the mesentery to the lanthanum nitrate and we came to a final conclusion that the penetration of the heavy salt is impeded by the presence of a basement membrane, localized between the mesothelial and connective tissue layers and that it was continuous to the basal lamina, located between neighbouring mesothelial cells; we could then observe that the lanthanum traveled through the cytoplasm and not in between mesothelial cells. In this paper we analyze the behavior of the mesentery in relation to the osmium-amine and we compare it to the observations made in our previous work. Generally speaking, we were unable to observe any reaction in any of the structures of the mesentery, except for some special cases. In those not very common cases, employing special techniques, we came to the conclusion that the osmium-amine reacts in the periphery (outer surface) of the mesentery and also penetrates, sometimes with no visible reaction, all the way to the elastic layer, where a reaction can be detected.

Amines↗
PubMed1986

Improvement of prolactin immunolabelling in osmium-fixed acrylic-embedded pituitary gland.

Immunolabelling of prolactin (PRL) with protein A-colloidal gold complex and tissue fine structure were enhanced after postfixation of pituitary gland with osmium tetroxide and embedment in acrylic momers (LR White). Thin sections were treated with sodium metaperiodate before immunocytochemistry. An intense PRL labelling was detected in secretory granules, Golgi complexes and extracellular accumulation of the hormone. The use of osmium greatly improved the fine structure of the tissue and its stability during acrylic embedment.

Acrylates↗
PubMed1975

[Characteristics of artefacts following fixation with glutaraldehyde and osmium tetroxide].

In the myocard and kidney of rats perfused with Karnovsyk's solution for 5--10 minutes then fixed for two more hours and postfixed in 1 per cent solution of osmium tetroxid in Millonig buffer, characteristic electrondense granules were observed. The structure of the organ appeared to be normal. Although the granules appeared to be diffuse, they presence was most marked on the membranes, on the surface of erythrocytes and in the pinocytic vacuoles both on counterstained slides and on those of without counterstaining. When postfixation was carried out with osmium-tetroxide solved in Veronal buffer artefacts did not occur. To avoid artefacts fixation in glutaraldehyd should not be followed by a postfixative containing phosphate buffer.

Aldehydes↗
PubMed1971

Microscopic fat cell size measurements on frozen-cut adipose tissue in comparison with automatic determinations of osmium-fixed fat cells.

Diameters of fat cells in adipose tissue slices, floating in an isoosmolar solution, were measured under a microscope. The slices were obtained from percutaneous biopsies by freeze-cutting after brief formaldehyde fixation. All cells in a given part of the slice were measured, thus avoiding selection. A normal distribution of fat cell diameters could be demonstrated with this method, as has been found with previously described methods. The error of the method was 2.6% for diameter and 8.0% for weight determinations. Storage of adipose tissue at 4 degrees C for 48 hr had no effects on cell size determinations. Results with this microscopic method were compared with those obtained from a previously described method for automatic determinations of osmium-fixed fat cells. The latter method was slightly modified by using a viscous electrolyte, which prevented sedimentation of large fat cells, and by using sonication to complete cell separation. The methods agreed closely. A method for calculating mean fat cell weight using osmium-fixed fat cells is described, which makes determinations of sample wet weight and ratio of lipid to wet weight unnecessary.

Adipose Tissue↗
PubMed1981

The structure of the endoplasmic reticulum revealed by osmium tetroxide-potassium ferricyanide staining.

Postfixation of plant tissues with a mixture of osmium tetroxide and potassium ferricyanide (OsFeCN) yields a selective staining of the endoplasmic reticulum (ER) and nuclear envelope (NE). The other cytoplasmic organelles and inclusions are evident, but by comparison with the NE-ER they are weakly contrasted. Demarcation of the NE-ER results from the enhanced deposition of an electron-opaque reaction product on the inner leaflet of the membrane that extends into the cisternal space. The procedure thus renders the NE-ER readily apparent even when the elements are sectioned parallel to their surface and makes it possible to easily visualize their cellular pattern. Ultrastructural studies reveal with clarity tubular reticula and fenestrated lamellae that are extensively interconnected into one continuous membrane system. Problems with the OsFeCN procedure include the inability of the reagent to stain the NE-ER in all cells of a tissue, the occasional staining of non-ER such as dictyosomal cisternae and plastids, and the failure to selectively stain the NE-ER in protoplasts or single wall-less cells. Results obtained with OsFeCN are compared with other ER fixatives and stains including potassium permanganate and zinc iodide-osmium tetroxide. Despite its problems, under optimal circumstances OsFeCN is judged to be superior to other stain-fixatives for selectively contrasting the NE-ER compartment and is recommended generally for ultrastructural investigations.

Endoplasmic Reticulum↗
PubMed1996

The osmium ammine-SO2 staining method for studying the in situ configuration of viral genomes in ultrathin sections of DNA virus infected cells.

The Feulgen-like osmium ammine-SO2 method developed by Cogliati and Gautier (CR Acad Sci Ser D 1973, 276, 3041-3044) stains the DNA at the ultrastructural level. Compared to several other techniques for detecting DNA, this method remains the only one revealing the configuration of the DNA molecules within the cell whatever their compactness. In the present article we summarize the results we obtained with the osmium ammine method in the study of the fate of viral genomes along the infectious cycles in several DNA virus infected cells including adenovirus, herpes simplex virus, simian virus 40 and poxvirus. The results are discussed in relation to the replicative and transcribing activities of viral DNA.

Adenoviridae Infections↗
PubMed1996

Osmium ammine-B and electron spectroscopic imaging of ribonucleoproteins: correlation of stain and phosphorus.

Ultra-thin sections of Chironomus salivary glands were stained in a non-Feulgen procedure with osmium ammine-B and imaged at several electron energy-loss windows. For two types of RNP-containing structures (ie Balbiani ring granules and endoplasmic reticulum), a significant spatial correlation was observed between stain distribution and net phosphorus distribution. Non-Feulgen osmium ammine-B staining does not require the use of ultra-thin sections and can approximate the distribution of nucleic acid phosphorus.

Animals↗
PubMed2003

Synthesis and nonlinear optical absorption of novel porphyrin-osmium-cluster complexes.

Reaction of azido(tetra-p-tolylporphyrinato)indium(III) [TTPInN(3)] and [Os(3)(mu-H)(2)(CO)(10)] in toluene at 80 degrees C overnight gave two major products, complexes 1 and 2. Complex 1 had an axial bridge of "NH", while 2 had an axial bridge of "N" between the porphyrin and osmium cluster moieties. Complex 1 could be converted to 2 when refluxed in toluene. These two novel porphyrin-osmium clusters are the first axially linked porphyrin-metal cluster complexes. UV/Vis spectroscopy revealed the significant ground state electronic perturbation in the capped complex 2, demonstrating that the remarkable electronic interaction of the moieties within the molecule was achieved by this special structural arrangement. In addition, the electrochemistry of 1 and 2 were investigated and their oxidation current voltage curves are similar to those of indium(III)-porphyrins with a metal-metal sigma bond such as [TPPInRe(CO)(5)] (TPP=tetraphenylporphyrin). The two new molecules also exhibit large nonlinear optical absorption at 532 nm with a ns pulse laser and are potential optical limiting materials for sensor protection in the visible region.

Journal Article↗