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At least 1,153 records · Page 64Linked to original sources
PubMed1989

Eosinophilic intracytoplasmic globules in pulmonary adenocarcinomas: a histochemical, immunohistochemical, and ultrastructural study of six cases.

Intracytoplasmic globules have been described in a variety of neoplastic and nonneoplastic conditions, but remain poorly defined. In a review of 100 consecutive cases of lung carcinomas, six cases of mucin-positive adenocarcinoma demonstrated eosinophilic intracytoplasmic globules that ranged in size from less than 1 to 20 mu in diameter. The globules were often located adjacent to areas of tumor necrosis, and occurred either singly or multiply within individual tumor cells. Globules were similar in morphologic appearance to Russell bodies in plasma cells or the eosinophilic globules in hepatocytes of patients with alpha-1-antitrypsin deficiency, but were morphologically distinct from intracytoplasmic mucin vacuoles. The globules were brightly positive with PAS stain with diastase, were brick red with Masson's trichrome stain, and showed variably positive staining with Mallory's phosphotungstic acid-hematoxylin and Ziehl-Nielson stains. Immunoperoxidase staining showed slight staining of some globules with albumin, IgG, IgA, and alpha-1-antitrypsin. Ultrastructurally the globules had a homogeneous density and were often associated with profiles of rough endoplasmic reticulum. We suggest that these globules represent secretory glycoprotein accumulated in the cytoplasm of tumor cells in areas of tumor cell injury.

Adenocarcinoma↗
PubMed1989

Phosphotungstate shows a heparin-like anticoagulant effect but inhibits heparin.

We examined the anticoagulant effects of phosphotungstate (PTA). PTA inhibited factors IIa and Xa activity only in the presence of antithrombin III (ATIII). The inhibitory effect of PTA on IIa was much smaller than that on Xa. When PTA was added to heparin (Hep), the inhibitory effect of Hep on IIa was reduced. As a result of charge interaction, PTA showed an inhibitory effect on anion transport activity of the erythrocyte, a potent salting-in effect and a metachromatic reaction on toluidine blue (TolB). Silicotungstate (STA) showed almost the same results as PTA. These effects of PTA and STA were not replaced by their constituents, tungstate, silicate and phosphate, but may arise from their high anionic valency.

Anticoagulants↗
PubMed1990

Phosphotungstate as a useful eluent for antithrombin III purification by heparin-agarose affinity chromatography.

We have recently found that phosphotungstate (PTA) has a heparin-like anticoagulant effect. In the present paper, we studied whether PTA is useful as an eluent of antithrombin III (ATIII) on heparin-Sepharose affinity chromatography. Human ATIII adsorbed on the heparin-Sepharose gel was eluted with NaCl buffer at the NaCl level of 1M. Whereas, PTA could elute ATIII at the level of less than 1mM and thus obtained ATIII fraction contained less impurities than such a fraction eluted with NaCl. Residual PTA in the eluate was easily decomposed by alkalization, being convenient for subsequent studies.

Antithrombin III↗
PubMed1985

Astroblastoma of pure type.

A rare case of astroblastoma of the pure type occurring in the left occipital lobe of a 54-year-old female is reported. The predominant histologic feature was that of perivascular pseudorosettes. The tumor tissues were not stained by the Mallory's phosphotungstic acid-hematoxylin, but the perikarya of some tumor cells were positively stained for the glial fibrillary acidic protein.

Astrocytoma↗
PubMed1984

Synaptic remodelling during development and maturation: junction differentiation and splitting as a mechanism for modifying connectivity.

Morphological variation of the synaptic active zone during later development and maturation (15-224 days) has been studied in the molecular layer of the rat occipital cortex. Both E-PTA stained and osmicated tissue have been used. In the E-PTA stained material the degree of specialization of the presynaptic thickening is directly related to junction length. Junctions with well-developed dense projections (Types A and B) are longest and continue to increase in length with maturation, suggesting that active remodelling of the synaptic apposition is an ongoing process. The presence of perforated junctions, possessing two or more regions with specializations of different maturity and different curvature, raises the possibility that these junctions may arise by the addition and differentiation of new paramembranous material at an existing junction. In osmicated tissue, presynaptic terminals possessing multiple active zones have been quantitated. The maturational increase in number of simple perforated junctions (Type 1), is paralleled by a smaller increase in the number of multiple perforated junctions (Type 2). A spine apparatus is frequently observed in these perforated terminals, suggesting that it is intimately involved in the reorganization. The direction of curvature of the closely apposed junctions is predominantly negative (indenting the postsynaptic process). Other types of arrangement, with separate postsynaptic processes, are described (Types 3-5), and micrographs suggestive of sequential stages in pre- and postsynaptic terminal splitting are presented. The total length of the postsynaptic thickening of perforated terminals is twice the mean synaptic length of non-perforated terminals, again suggestive that duplication of the active zone may have occurred. Division of existing synaptic terminals by duplication and subsequent splitting would readily account for the increased dendritic spinal numbers seen in Golgi preparations of animals raised under enriched conditions. This would be a straight-forward mechanism by which reinforcement of neuronal connections could occur in response to use.

Animals↗
PubMed1992

A new electron microscope positive staining method for viruses in suspension.

A new procedure for the positive staining of viruses in suspension, the Tokuyasu staining procedure (TSP), was evaluated using a non-enveloped virus, rotavirus; an enveloped virus, rubella virus and two glutaraldehyde-treated enveloped viruses, Human T Cell Lymphotropic Virus Type I (HTLV-I) and Human Immunodeficiency Virus Type 1 (HIV-1) as models. The TSP involves an initial staining of the virus with uranyl acetate (UA) followed by thin embedding in a mixture of UA and polyvinyl alcohol (PVA). Using aqueous UA for the TSP, a combination of positively and negatively stained particles was seen for both rotavirus and rubella virus. With glutaraldehyde-fixed HTLV-I and HIV-1, stain penetration did not occur and only negative staining was observed. The substitution of methanolic UA for aqueous UA in the TSP resulted in only positive staining of rotavirus and rubella virus. The change in procedure also resulted in stain penetration of the glutaraldehyde-fixed HTLV-I and HIV-1 to give positively stained particles. Some novel morphological features of rotavirus and rubella virus structure were observed by the TSP.

Glutaral↗
PubMed1986

Postsynaptic density visualized by whole mount electron microscopy.

Detergent-unextractable structures of synaptic plasma membrane of rat cerebrum were observed by whole mount electron microscopy. The globular structures were identified as postsynaptic densities (PSDs) from several criteria and appeared to consist of folded strings, to which a number of other molecules might be attached. Some of the globular structures were attached with subsynaptic webs. The structures contained a number of finely striated small strips (10-20 nm wide, 60-100 nm long), parts of which were peeled off from PSD cytoskeletal base by N-lauroyl sarcosinate.

Animals↗
PubMed1981

On the negative straining of the protein crystal structure.

It has been shown that in some cases negative staining reveals structure with details down to 0.4 nm in size, the nature of protein playing a key role. Various stains seem to interact with different parts of a thermitase (a serine protease) molecule, which results in intensity changes in electron diffraction patterns.

Crystallization↗
PubMed1985

Ultrastructure of gap junctions in the central nervous system of Lymnaea stagnalis with particular reference to electrotonic coupling between the neuroendocrine caudodorsal cells.

Presence and structure of gap junctions have been studied at the ultrastructural level in the central nervous system of the freshwater snail Lymnaea stagnalis. Gap junctions are clearly visible in thin sections of glutaraldehyde-fixed and phosphotungstic acid-stained material as well as in freeze-fracture preparations. Various types can be distinguished on the basis of junctional size and shape, and numerical density, diameter, spacing and arrangement of junctional particles. Junctions are present between neurones and between glial cells. The neuroendocrine ovulation-hormone-producing caudodorsal cells show gap junctions at four sites, viz. between somata, between axons in the "loop area" and in the intercerebral commissure and between neurohaemal axon terminals. These junctions show common characteristics as to numerical density, diameter, spacing and arrangement of junctional particles, but morphometry reveals different mean values for junctional size and numerical density. Values are the highest for axons in the loop area, intermediate for axons crossing the commissure, and the lowest for somata and axon terminals. It is proposed that the gap junctions particularly play a role in electrotonic intercellular coupling. The results strongly suggest that the gap junctions between the caudodorsal cells--especially those in the loop area and between the crossing axons--are the morphological correlates of the previously demonstrated electrotonic coupling between these cells. This coupling may enable all cells of the network to act synchronously so that a large amount of ovulation-hormone can be released within a short period of electrical activity (the discharge).

Animals↗
PubMed1995

Automatic gas chromatographic determination of the high-density-lipoprotein cholesterol and total cholesterol in serum.

A new analytical method that combines on-line precipitation-filtration, enzymatic hydrolysis, extraction and gas chromatography was developed for the determination of total cholesterol and high-density-lipoprotein cholesterol in human serum. Very-low-density lipoprotein, intermediate-density lipoprotein and low-density lipoprotein are precipitated with sodium phosphotungstate and magnesium chloride; then, the serum is continuously filtered and unprecipitated high-density-lipoprotein cholesterol is enzymatically hydrolyzed and finally determined as cholesterol by gas chromatography. Total cholesterol is also determined by direct introduction of the serum into the proposed system. The proposed method was validated by analyzing a lipid control serum with certified contents of high-density-lipoprotein cholesterol and total cholesterol. The results obtained were consistent with the certified contents.

Cholesterol↗
PubMed1992

A rapid and simple quantification of human apolipoprotein E-rich high-density lipoproteins in serum.

A rapid and simple method for the quantitative determination of human serum apo E-rich high-density lipoproteins is described. A sample was divided into two parts; one part was mixed with an equal volume of 13% polyethylene glycol 6000, and the other part was mixed with a solution containing dextran sulfate, sodium phosphotungstate, and Mg2+, respectively. The mixed solutions were centrifuged (2000 g; 15 min). The supernate obtained by the former procedure contained both apo E-rich HDL and apo E-poor HDL, but that obtained by the latter procedure contained solely apo E-poor HDL. The serum apo E-rich HDL concentration in terms of apo E (E) and cholesterol (C), was given by the following equations: E = EP x 2, and C = (CP - CD) x 2, where EP and CP were the concentrations of apo E and cholesterol, respectively, in the supernate obtained with 13% polyethylene glycol, and CD was the concentration of cholesterol in the supernate obtained with the mixture solution of dextran sulfate, sodium phosphotungstate, and Mg2+. Normal serum apo E-rich HDL concentrations were 2.6 +/- 1.5 and 6.7 +/- 2.3 mg/dl (means +/- SD, n = 38) in terms of apo E and cholesterol, respectively. Apo E-rich HDL was increased strikingly in the sera from three patients with hepatobiliary diseases.

Adult↗
PubMedDate not supplied

Structure of paracrystalline arrays on outer membranes of rat-liver and rat-heart mitochondria.

Crystalline arrays are induced in outer membranes of rat-liver and rat-heart mitochondria by phosphotungstate and silicotungstate. The basic structure of the arrays has been determined by correlation averaging of electron microscopic images of side views of tubular arrays and en face views of planar arrays. The arrays consist of rows of bilobed projecting subunits and are similar (in lattice parameters and projected subunit dimensions) to periodic arrays of ion transport ATPases, e.g., arrays of Ca(2+)-ATPase induced by vanadate in sarcoplasmic reticulum. Hexokinase-labeled colloidal gold particles do not specifically decorate the arrays, suggesting that the hexokinase receptor (VDAC channel) is not a component of the arrays.

Animals↗
PubMed2004

Alterations of N-ethylmaleimide-sensitive atpase following transient cerebral ischemia.

Neuronal repair following injury requires recruitment of large amounts of membranous proteins into synaptic and other cell membranes, which is carried out by the fusion of transport vesicles to their target membranes. A critical molecule responsible for assemblage of membranous proteins is N-ethylmaleimide-sensitive factor (NSF) which is an ATPase. To study whether NSF is involved in ischemic neurological deficits and delayed neuronal death, we investigated alterations of NSF after transient cerebral ischemia by means of biochemical methods, as well as confocal and electron microscopy. We found that transient cerebral ischemia induced depletion of free NSF and concomitantly relocalization of NSF into the Triton X-100-insoluble fraction including postsynaptic densities in CA1 neurons during the postischemic period. The NSF alterations are accompanied by accumulation of large quantities of intracellular vesicles in CA1 neurons that are undergoing delayed neuronal death after transient cerebral ischemia. Therefore, permanent depletion of free NSF and relocalization of NSF into the Triton X-100-insoluble fraction may disable the vesicle fusion machinery necessary for repair of synaptic injury, and ultimately leads to synaptic dysfunction and delayed neuronal death in CA1 neurons after transient cerebral ischemia.

Adenosine Triphosphatases↗
PubMed1984

Comparison of phosphotungstate and dextran sulfate-Mg2+ precipitation procedures for determination of high density lipoprotein cholesterol.

Because of the controversy over the best method for assaying high density lipoprotein (HDL) cholesterol in the clinical laboratory, a commonly used phosphotungstate method for precipitating low density and very low density lipoproteins (LDL and VLDL) was compared with a recently recommended dextran sulfate precipitation method. The accuracy and precision of HDL cholesterol determinations were similar for both methods. Either of these procedures would appear to be equally satisfactory for the assay of HDL cholesterol in the clinical laboratory.

Apolipoprotein A-I↗
PubMed1995

Type I collagen packing, conformation of the triclinic unit cell.

The X-ray diffraction pattern of tendon collagen can contain a number of sharp Bragg peaks indicating three-dimensional crystallinity of the sample. Optimal diffraction images have been obtained with a high flux synchrotron X-ray source and a carefully maintained sample environment and staining techniques. The Bragg peaks are always superimposed on a diffuse background. This makes interpretation of data difficult and a number of conflicting models of collagen packing have been proposed. The removal of the diffuse scatter from the images allows the Bragg peaks to be seen on a relatively flat background. This was conducted by modelling the background points as a series of two-dimensional polynomial functions. The resultant set of observed Bragg reflections serves as an excellent basis to test the validity of two contradictory packing modes; (1) the triclinic model, Fraser et al., (2) the microfibril model, Kajava. From this it can easily be seen that the model proposed by Kajava is inappropriate, since there is limited agreement between predicted positions of reflections and the positions of observable reflections on film. The packing of collagen molecules on a triclinic lattice is favoured by this criterion.

Animals↗