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At least 595 records · Page 33Linked to original sources
PubMed1991

Synapses in developing cingulate and hippocampal cortices in undernourished rats.

Differential patterns of developmental changes were observed between 10 and 150 days of age in numerical densities of ethanolic-phosphotungstic acid stained synapses in the molecular layer of cingulate cortex (area 29 c,d) and hippocampus (CA1)-dentate region in rat. Chronic caloric undernutrition commencing prenatally caused considerable reduction of synaptic densities up to 45 days of age in both the cortices, but showed opposite trends subsequently; the density attained was higher than control in the cingulate area, but lower than control in hippocampus-dentate area. Post-weaning rehabilitatory nutrition resulted in a reduced deviation from normal in the cingulate area but not in the hippocampus-dentate area.

Aging↗
PubMed1995

Sudden infant death syndrome: increased number of synapses in the hypoglossal nucleus.

The medulla was sampled from nine cases of sudden infant death syndrome (SIDS) and from six age-matched control cases without neurological disease. Morphometric analyses were performed on serial Nissl sections through the hypoglossal nucleus on the left side of the medulla. The total volume of the nucleus and both the numerical density (Nv, cells per mm3) and total number of neurons were measured. Tissue from the remaining hypoglossal nucleus was prepared for electron microscopy using the ethanolic phosphotungstic acid method to stain synaptic contacts. Stereological analyses were performed to determine the Nv and total number of synapses. Total volume of the hypoglossal nucleus was significantly greater (36%) in SIDS cases than in controls. The Nv of neurons was significantly less than in controls (28%), although the total number of neurons did not differ significantly. The mean profile area of motor neuron cell bodies was significantly greater (30%) in SIDS cases, with no differences in the mean profile areas for interneurons or glia. The Nv of synapses did not differ significantly between SIDS cases and controls, although the total number of synapses was greater (61%) in SIDS. These abnormalities in growth indicate a greater volume of neuropil in a hypoglossal nucleus containing a normal complement of neurons. The greater number of synapses in SIDS cases is consistent with a failure to eliminate normally extraneous synapses during early development.

Brain↗
PubMed1976

Demonstration of a core in poliovirus particles by electron microscopy.

Electron microscopic examination of poliovirus in CsCl-solutions without conventional staining with phosphotungstic acid or uranyl acetate revealed the existence of cores inside poliovirus particles. Empty capsids could not be visualized by this technique. Evidently, CsCl can enhance the contrast of the virus particle to an extent sufficient for the study of poliovirus particles by electron microscopy under conditions in which they exhibit specific properties.

Capsid↗
PubMed1983

In situ electron microscopic observation of negatively stained tissue culture cells contaminated with mycoplasmas.

A simple, fast, and in situ method of detecting the inapparent infection of cultured cells with mycoplasmas is reported. Animal cells grown on Formvar-coated electron microscopic grids were directly fixed with glutaraldehyde, negatively stained with phosphotungstic acid and examined by transmission electron microscopy. Cells contaminated with mycoplasmas could be discriminated from uncontaminated cells. The micro-organisms in the negatively stained preparations corresponded with those revealed by thin sectioning, and the distribution of mycoplasmas in cultured cells coincided with those revealed by the Hoechst staining method. Most of the highly resolved mycoplasmas were polymorphic, and closely associated with host cells; often more than 500 organisms per host cell were seen.

Animals↗
PubMed2003

Isolation and characterization of a new species of kobuvirus associated with cattle.

A cytopathic agent was isolated using Vero cells from the culture medium of HeLa cells that had been used for more than 30 years in our laboratory. This agent, termed U-1 strain, was serially passed in Vero cells with distinct CPE. Particles of U-1 strain negatively stained with phosphotungstic acid exhibited a distinct surface that resembled Aichi virus. The RNA genome of U-1 strain comprises 8374 nt, with a genome organization analogous to that of picornaviruses. Possible cleavage sites of the large ORF, which encoded a leader protein prior to the capsid protein region, were assigned following amino acid alignment with Aichi virus. The virus sequence had 33 and 75 % amino acid identity with the Aichi virus VP1 and 3D regions, respectively, but no more than 23 and 36 % with those of the prototype strains of other PICORNAVIRIDAE: The dendrogram based on the P1, P2 and P3 proteins indicated that U-1 strain is genetically included in the genus Kobuvirus but is distinct from Aichi virus. Of 72 cattle sera, 43 (59.7 %) were positive for neutralizing antibody against U-1 strain at a titre of 1 : 8 or more. However, sera from 190 humans, 242 monkeys, 139 pigs, 5 horses, 22 dogs and 9 cats did not neutralize U-1 strain at a 1 : 4 dilution. RNA corresponding to U-1 strain was detected in 12 (16.7 %) of 72 faecal samples from cattle by RT-PCR. These results indicated that U-1 strain, suspected to be a contaminant from calf sera, is a new species of the genus Kobuvirus, now termed bovine kobuvirus.

5' Untranslated Regions↗
PubMed1969

Properties and Ultrastructure of Phycoerythrin From Porphyridium cruentum.

Phycoerythrin, a photosynthetic accessory pigment, was isolated from Porphyridium cruentum and examined by electron microscopy and disc gel electrophoresis. The absorption monomer, with maxima at 563, 545, and a shoulder at 500 nm, has a molecular weight of about 300,000. With phosphotungstic acid staining it appears as a tightly structured disc-shaped particle possessing a mean diameter of 101 +/- 0.4A and height of 54 +/- 0.7A. The absorption maxima remained the same in glutaraldehyde fixed material, and in dimer and trimer aggregates. Treatment with sodium dodecyl sulfate caused a breakdown into smaller units accompanied by a loss of the 563 nm peak. It is suggested that this absorption monomer is the in vivo functional species and comparable to the phycocyanin hexamer, but structurally distinguishable at the ultrastructural level. It has been calculated that about 35 phycobiliprotein molecules can be contained within each phycobilisome. There are 1.4 x 10(3) chlorophyll molecules per phycobilisome, but not contained within it.

Journal Article↗
PubMed1976

Isolation of plasma membranes from corn roots by sucrose density gradient centrifugation: an anomalous effect of ficoll.

An investigation was conducted into the isolation of plasma membrane vesicles from primary roots of corn (Zea mays L., WF9 x M14) by sucrose density gradient centrifugation. Identification of plasma membranes in cell fractions was by specific staining with the periodic-chromic-phosphotungstic acid procedure. Plasma membrane vesicles were rich in K(+)-stimulated ATPase activity at pH 6.5, and equilibrated in linear gradients of sucrose at a peak density of about 1.165 g/cc. It was necessary to remove mitochondria (equilibrium density of 1.18 g/cc) from the homogenate before density gradient centrifugation to minimize mitochondrial contamination of the plasma membrane fraction. Endoplasmic reticulum (NADH-cytochrome c reductase) and Golgi apparatus (latent IDPase) had equilibrium densities in sucrose of about 1.10 g/cc and 1.12 to 1.15 g/cc, respectively. A correlation (r = 0.975) was observed between K(+)-stimulated ATPase activity at pH 6.5 and the content of plasma membranes in various cell fractions. ATPase activity at pH 9 and cytochrome c oxidase activity were also correlated.A major peak of ATPase activity at pH 6.5 was observed at low density in Ficoll after nonequilibrium centrifugation in a combination Ficoll-sucrose gradient. Twenty to forty percent of the vesicles in this ATPase fraction stained positively for plasma membranes, and with equilibrium centrifugation the major portion of the ATPase activity shifted to densities in sucrose which were characteristic of plasma membranes. All major vesicular ATPase activities observed in Ficoll or sucrose contained substantial amounts of plasma membranes. For unknown reasons, mitochondria and plasma membranes equilibrated over a broader density range and at lower peak densities in sucrose as a result of equilibrium centrifugation through Ficoll.

Journal Article↗
PubMed1989

Cytochemistry of trichohyalin granules: a possible role for cornification of inner root sheath cell in the hair follicle.

We studied ultracytochemically how trichohyalin granules (TGs) were involved in the cornification of the inner root sheath (IRS) cells in the hair follicle. After storing unfixed mouse skin samples in glycerol and then low ionic strength salt solution (G-LISS), the TGs reduced electron-dense amorphous material (EDM) to various degrees, with the appearance of filamentous material in routine staining. As the IRS cells were differentiating, these changes in the TGs became successively prominent; Some TGs consisted of the filamentous material and residual granular EDM, showing a "filamentogranular structure". In the cells in transition to cornified cells, or transitional cells, the EDM of the TGs disappeared and consisted of only filamentous material which was intertwined with keratin filaments (KFs). The internal substructure of the TGs induced by the G-LISS treatment stained well with ethanolic phosphotungstic acid, which reacts with basic proteins, and the KFs associated with the TGs also stained well. In skin samples not treated with G-LISS, the TGs of the transitional cells often exhibited fibrogranular structure after PTA staining to detect tissue basic proteins, suggesting a release of PTA stainable proteins(s) by the TGs in living transitional cells. The KFs of the cornified cells were more intensively stained and thicker (about 20 nm wide) than those of the differentiating IRS cells. These findings suggest that the TGs may contain at least two kinds of basic proteins; One is G-LISS-soluble, and the other is a very insoluble filamentous protein. These protein materials may be added to or incorporated into the KFs in the cornified cells with the disappearance of the TGs, since the KFs are markedly thick with PTA staining.

Animals↗
PubMed1990

Hair follicle nevus with hyperplasia of smooth and striated muscle.

We report a peculiar nevus which occurred on the left side of the chin of an 18-year-old male. It had been present for four years and had grown rapidly during the last year. Histologically, many hair follicles, smooth muscles, and striated muscles were found within the reticular dermis. The hair follicles were accompanied by mature sebaceous glands; numerous eccrine glands were seen in the middle and deep dermis. Immunohistochemical stain and phosphotungstic acid hematoxylin stain supported the fact that the muscles seen between the follicles were both smooth and striated. This nevus was considered to be a hair follicle nevus accompanied by hyperplasia of smooth muscles and striated muscles.

Adolescent↗
PubMed1995

Extravasation of macromolecules and possible trapping of transforming growth factor-beta in venous ulceration.

The pathogenesis of venous ulceration is thought to involve formation of pericapillary fibrin cuffs as a result of venous hypertension, and a recent hypothesis suggests that extravasated plasma proteins may bind or trap growth factors. We have compared the tissue distribution of fibrin cuffs, plasma proteins, procollagen, and transforming growth factors (TGF-beta 1 and TGF-beta 2) within venous ulcers and normally healing graft donor sites. In venous ulcers, the papillary dermis and the ulcer bed contained convoluted capillaries with phosphotungstic acid haematoxylin-positive pericapillary fibrin cuffs. By immunohistochemical staining, the cuffs were positive for actin, and contained massively redundant lamellae of basement membrane material which stained positive for type IV collagen. Extravasated factor XIIIa and alpha 2-macroglobulin were present within the fibrin cuffs. Increased numbers of type I procollagen positive fibroblasts, and increased TGF-beta 1 immunoreactivity were present within the fibrin cuffs, but not in the provisional matrix in the ulcer bed around the cuffs. In contrast, in normally healing graft donor sites, tortuous capillaries and fibrin cuffs were absent, factor XIIIa and alpha 1-macroglobulin were restricted to the lumina of vessels, and procollagen and TGF-beta immunoreactivity were present within the granulation tissue and adjacent dermal matrix at the wound margin. These observations suggest that growth factors critical in wound healing, such as TGF-beta, are present within venous ulcers, but are abnormally distributed. Their distribution within fibrin cuffs and co-localization with extravasated plasma proteins, particularly alpha 2-macroglobulin, which is a recognized scavenger molecule for TGF-beta and other growth factors, provides evidence for a possible 'trapping' of growth factors in venous ulcers.

Blood Proteins↗
PubMed1982

Cell coat of podocytes in patients with nephrotic syndrome.

Renal biopsies from 23 patients with the nephrotic syndrome and five patients with slight or no proteinuria were examined for the presence of cell coat of podocytes by light and electron microscopy. Of those with nephrotic syndrome, five had minimal change disease, nine focal glomerular sclerosis, six membraneous nephropathy and three amyloidosis. Colloidal iron and phosphotungstic acid stains were used for the demonstration of anionic and neutral polysaccharide components of the cell coat. On light microscopy, the colloidal iron reaction showed a reduction in intensity of the stain in glomeruli of patients with massive proteinuria, as compared to those with slight or no proteinuria. On electron microscopy, only the cell coat lining the surface of the foot processes disappeared parallel to the loss of these structures, while the coat covering the surface facing the urinary space remained unchanged with both stains.

Cell Membrane↗
PubMed1984

Gastric parietal cell carcinoma--a newly recognized entity: light microscopic and ultrastructural features.

Three cases of gastric parietal cell carcinoma are described. Tumour cells are round to polygonal, with abundant eosinophilic, granular cytoplasm reactive with phosphotungstic acid haematoxylin and Luxol Fast Blue. Ultrastructurally the tumour cells are characterized by abundant mitochondria, tubulovesicles, intracellular canaliculi and intercellular lamina filled with undulated microvilli.

Aged↗
PubMed1976

The influence of the embedding medium when staining for electron microscopy: the penetration of stains into plastic sections.

Using a sectioned-section procedure it was found that only a few structures, e.g. the connective tissue elements, were deeply penetrated by phosphotungstic acid (PTA) and uranyl acetate (UA). Reynold's lead citrate appeared to penetrate more generally. Using stains selective for the embedding medium, and also observing the surfaces of shadowed sections, it was concluded that structures readily penetrated by polar stains were only poorly infiltrated by non-polar embedding media. It is argued that this differential infiltration leading to differential penetration by polar stains largely controls the pattern of staining of ultrathin sections by PTA and UA.

Animals↗
PubMed1982

Imaging of outer segment periodicities in unstained cryoultramicrotomy sections of the frog retina.

Frog retinas were examined following cryoultramicrotomy. The extent of glutaraldehyde cross-linking ranged from maximally 2% for 2 h to no cross-linking. When the tissue was cryoprotected, the effects of hypotonic, isotonic and hypertonic media on outer segment banding periodicities were studied. The specimen was cryosectioned at 193 K to 113 K with sections collected on a dry knife (213 K to 123 K). The sections were freeze-dried and only rehydrated with phosphotungstic acid section stain when transmission electron microscopy was used to establish the extent of gross retinal morphology for each fixation protocol employed. As the extreme of no cross-linking and no cryoprotection was approached and reached, conventional sections which displayed extensive retinal morphology were not obtained. Instead, fragments of retinal tissue resulted which showed periodicities of alternating light and dark bands. These periodicities are interpreted as photoreceptor outer segment discs with contrast formation depending upon an interplay between three factors: mass density differences between disc and interdisc space, section cutting angle, and section thickness.

Animals↗
PubMed1991

Application of high-resolution scanning electron microscopy to biological macromolecules.

The development of ultrahigh-resolution scanning electron microscopes (SEMs) has made the observation of biological macromolecules feasible, but adequate preparation methods have not yet been established. Although it has been possible to observe some molecules after they have been spread on a carbon substrate, this method has not proved suitable for other molecules which exhibit lower contrast, or are more susceptible to damage by the electron beam. In this study we have applied heavy-metal impregnation methods using phosphotungstic acid, uranyl acetate, or osmium tetroxide mordanted by tannic acid. In addition, contamination due to the electron beam was reduced by improving the vacuum in the specimen chamber, and by the use of a heated specimen stage. Using these measures, haemocyanin, ferritin, apoferritin, thyroglobulin and immunoglobulin M were successfully image. Ultrahigh-resolution SEM seems likely to become an important means for studying the morphology of biological macromolecules.

Animals↗
PubMed1975

Comparative electron-microscope studies on type-III and type-I collagens.

Long-spacing-segment crystallites prepared from type III collagen with the chain composition [alpha1(III)]3 and type I collagen with the chain composition [alpha(I)]i12alpha2 have been compared in the electron microscope after positive. staining with phosphotungstic acid and uranyl acetate. The comparison revealed several differences in intensities of the cross-striation bands as well as significant differences in band positions. The latter occur most prominently in three distinct regions of the crystallites. Further, crystallites prepared from type III collagen contain an additional intensely staining band in an area corresponding to the carboxy-terminal end of the molecule. The latter band is still observed following limited pepsin digestion and presumably represents a slight elongation of the helical portion of the type III molecule when compared to the type I molecule. In spite of the somewhat altered distribution of charged groups as indicated in studies on the long-spacing-segment crystallites, type III molecules are capable of forming fibrils of the native type with a cross-striation pattern and periodicity virtually identical to that observed when type I molecules are precipitated as native fibers.

Amino Acid Sequence↗
PubMed1994

Multicentric lymphoma involving large granular lymphocytes in a cow.

This case report describes for the first time in the literature a bovine multicentric lymphoma involving large granular lymphocytes (LGL). Clinically, the cow had typical manifestations of multicentric lymphoma with nonspecific signs. Most lymphocytes in cytological specimens from blood and lymph nodes had an LGL-morphology. Histopathologically malignant LGLs were found in the liver, kidneys, and lungs. The azurophilic granules were clearly seen with May-Grünwald-Giemsa stain. The granules were slightly eosinophilic as shown with hematoxylin-eosin stain, and most stained intensively dark with phosphotungstic acid hematoxylin.

Animals↗
PubMed2006

Auricular rhabdomyosarcoma in a rat.

An ear (auricular) neoplasm from a 1-year-old male rat was removed surgically and examined histologically. Macroscopically, the neoplasm was firm, white and measured (0.5 x 0.5 cm). Microscopically, the neoplasm was expansile, non-encapsulated, and composed of large, pleomorphic, polygonal to spindle-shaped cells containing multiple nuclei. Using immunohistochemical and chemical stains, the neoplastic cells were positive for vimentin, myoglobin, phosphotungstic acid haematoxylin and desmin, but had no immunoreactivity for cytokeratin or alpha-smooth muscle actin. On the basis of histopathological, immunohistochemical and histochemical stains, a diagnosis of auricular rhabdomyosarcoma was made. Although reported infrequently in human, this is, to the author's knowledge, the first report that describes the detailed gross, histopathological, histochemical and immunohistochemical findings of auricular rhabdomyosarcoma in a rat.

Animals↗