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At least 1,243 records · Page 69Linked to original sources
PubMed1983

Cerebral veins: fluorescence histochemistry, electron microscopy, and in vitro reactivity.

Pial veins, choroid plexus veins, and the cerebri magna vein were investigated with regard to their ultrastructural organization, adrenergic nerve supply, and in vitro reactivity. The vessel walls consisted of a continuous layer of endothelial cells, large amounts of collagenous material, and occasional pericytes. Smooth muscle cells were observed only in a few specimens from the cerebri magna vein. All veins were surrounded by adrenergic nerve fibres. Potassium (124 mM) and noradrenaline (10(-5) - 10(-4) M) induced small contractions (0.2-0.5 mN) of isolated veins during in vitro conditions. The magnitude of these responses was less than one-tenth of that obtained in small pial arteries.

Animals↗
PubMed2000

The vascular bed in the rabbit ear: microangiography and scanning electron microscopy of vascular corrosion casts.

The vascular bed of the rabbit ear has been studied with light microscopy, microangiography and scanning electron microscopy of resin casts in a series of 20 ears. The major arteries supplying the ear were the central and rostral auricular branches of the caudal auricular artery. The caudal auricular branch was not observed, except as a small vessel supplying the rostral auricular base. The central auricular branch supplied blood to most of the auricular integument and was surrounded by capillaries extended from those supplying the skin. The periarterial capillaries formed a fine, compact network in the tunica media and were closely related to the central auricular branch. Evidence is presented suggesting that this vascular mechanism has a counter-current heat-exchange function for regulating body temperature. The artery had the well-developed internal elastic lamina and intimal cushions that regulate blood flow at the branching sites. A number of arteriovenous anastomoses were also observed between arterioles and venules, particularly in marginal regions of the ear. The intimal cushions and arteriovenous anastomoses might play an additional role in thermoregulation by regulating local blood flow in the ear.

Angiography↗
PubMed1997

[Interaction of silicone oil with various intraocular lenses. A light and scanning electron microscopy study].

BACKGROUND: Silicone oil is increasingly used as an intravitreal tamponade in severe forms of vitreoretinal disorders, also in pseudophakic eyes. In some patients silicone oil was observed to be adherent to the intraocular implant. MATERIAL AND METHODS: To investigate the interaction of silicone oil with IOL-materials and the influence of lipoproteins of the serum on this interaction we used the following in vitro experimental set-up: Sterile IOLs of different IOL-materials (e.g. PMMA, silicone, hydrogel) and surface-modifications (e.g. Pharmacia 809P and 809C, Soflex LI41U, Alcon AcrySof M60BM, Allergan SI-30NB, SI-40NB, Chiron adatomed 90D, C10 and C31UB, MemoryLens U940A, Corneal ISHEMA 66, Storz H60M) were stored in vitro together with silicone oil (1000 centistokes) with and without a fresh serum solution at 37 degrees Celsius. This combination was rotated slowly and mixed thoroughly three times a day. After 3 and 6 months and a standardized special preparation in an ultrasound bath and air treatment, the IOLs were examined by light microscopy followed by scanning electron microscopy. RESULTS: Silicone oil strongly adhered to holes and to the IOL surface especially in silicone and PMMA IOLs. Highly hydrophylic IOLs-like the heparin-surface-modified and hydrogel IOL-cleared from silicone oil relatively early. This effect was more pronounced in the group with lipid-/serum solution than without. In some silicone IOLs silicone oil was strongly adherent to the lens and it was nearly impossible to wash off the oil even when using an alcoholic solution. One silicone IOL lost its haptics in the serum-oil-IOL-mixture, another lost small particles from the IOL surface. CONCLUSION: Silicone oil is more adherent to hydrophobic IOLs than to hydrophylic IOLs. Lipoproteins of the serum play an important role in facilitating an effect of silicone oil on IOL materials. We recommend highly hydrophylic especially surface-modified IOLs for lens implantation following vitreoretinal silicone oil surgery. Implantation of silicone IOLs in vitreoretinal high risk eyes should be avoided.

Equipment Failure Analysis↗
PubMed1971

Visualization of single heavy atoms by dark field electron microscopy.

Dark field electronmicrographs of atoms of palladium, iodine, platinum, osmium, and uranium in model compounds have been obtained. Statistical analyses and a series of blind tests demonstrate the validity of the results. Moreover, optical density measurements of the images indicate that the observed relative scattering cross-sections of these atoms agree well with the theoretical cross-sections calculated from a Thomas-Fermi-Dirac model of the atom.

Bacteriophages↗
PubMed1965

Localization of a basic protein in the myelin of various species with the aid of fluorescence and electron microscopy.

In this study, alanine was shown to be the N-terminal amino acid of a basic protein of low molecular weight that was isolated from either human or guinea pig brain. Antibodies prepared against the guinea pig protein were labeled with either fluorescein or ferritin. Studies with the labeled antibodies showed that an immunohistochemically similar protein is found in the myelin sheaths of central and peripheral nervous tissues of chicken and frog and a variety of mammalian species. Loss of integrity of the myelin during processing was shown to enhance markedly the antigen-antibody reaction.

Alanine↗
PubMed1974

Monolayer cultures derived from neonatal hamster pancreas. Light and electron microscopy.

Cells derived by trypsinization of neonatal golden hamster pancreas were cultured in modified Eagle's medium for 120 h in the presence of glucose (0.8 mg/ml) and for an additional 48 h in medium containing glucose (0.8 or 3.1 mg/ml) or tolbutamide (1,000 microg/ml) plus glucose (0.8 mg/ml). At day 7, cultures were stained differentially for light microscopy or examined by electron microscopy. Immunoreactive insulin (IRI) and immunoreactive glucagon (IRG) in the culture medium were measured by standard immunoassay procedures. Staining properties and ultrastructural appearance of cultured cells were comparable to those of the intact neonatal hamster pancreas. Cultures consisted predominantly of cells possessing aldehyde fuchsin positive (AF(+)) cytoplasmic granules resembling ultrastructurally those of the intact neonatal pancreatic beta cells and additionally, those of fibroblastoid, acinar, acino-insular, and aldehyde fuchsin negative (AF(-)) argyrophilic cells. IRI release rate by the cultured cells was increased in the presence of elevated glucose or tolbutamide which paralleled the loss of AF(+) granulation, but IRG release rate was suppressed by elevated glucose concentration. These findings indicate that these monolayer cultures consist of most of the cell types occurring in the neonatal pancreas, including endocrinologically competent islet cells.

Animals↗