Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Freeze fixation-dehydration was used for the first time in the preparation of attached Gyrodactylus for SEM viewing. The technique provided instant immobilization of specimens before death and negligible shrinkage throughout the fixation-dehydration process. Comparisons of sample means of two linear measurements of attached opisthaptors showed 20% more shrinkage of Gyrodactylus fixed using 10% neutral buffered formalin than those which were freeze fixed. Freeze fixation-dehydration was excellent for the study of gross external morphology of attached Gyrodactylus. However, the freeze fixation-dehydration process may cause disruption of intracellular structural components making delicate tissues brittle and more prone to damage during subsequent manipulation.
 ...
PMID:Freeze fixation-dehydration as a method of preparation of Gyrodactylus (Monogenea) for SEM. 899 16

The cerebellar Golgi cells of mouse, teleost fish, primate and human species have been studied by means of light and Golgi light microscopic techniques, confocal laser scanning microscopy, slicing technique, ethanol-cryofracturing and freeze-fracture methods for scanning electron microscopy and ultrathin sectioning and freeze-etching replicas for transmission electron microscopy. The Golgi cells appeared in the granular layer as polygonal, stellate, round or fusiform macroneurons surrounded by the granule cell groups. They exhibited ascending dendrites toward the molecular layer and horizontal dendrites and a short beaded axonal plexus confined to the granular layer. Scanning electron microscopy revealed their three-dimensional neuronal geometry and smooth outer surfaces. Freeze-fracture method for SEM showed the stereospatial cytoplasmic arrangement of endoplasmic reticulum, cell organelles and nuclear envelope. By means of transmission electron microscopy the asymmetric synaptic connections of Golgi cell horizontal dendrites--with mossy fiber rosettes at the cerebellar glomerulus--and of Golgi cell axons--with granule cell dendrites at the periphery of glomerular region--were identified. At the molecular layer, Golgi cell ascending dendrites exhibited short neckless spines establishing asymmetric contacts with granule cell axons or parallel fibers. Shaft asymmetric axodendritic and axospinodendritic contacts between Golgi cell dendrites and climbing fibers were also found in the molecular layer.
 ...
PMID:Correlative microscopy of cerebellar Golgi cells. 1089 96

A correlative microscopic study of vertebrate cerebellar mossy fiber glomeruli has been carried out to obtain a three-dimensional view of the multisynaptic contacts formed by afferent mossy fibers with the granule and Golgi cell dendrites and by the monosynaptic relationship of Golgi cell axonal ramifications with granule cell dendrites. Samples of mice, hamsters, teleost fishes and human species were studied by means of one of the following procedures: confocal laser scanning microscopy (CLSM), ethanol-cryofracturing technique and conventional scanning electron microscopy (CSEM) and transmission electron microscopy (TEM) by ultrathin sections and freeze-etching replicas. CLSM, by means of montages of z-series of the cerebellar granular layer, provided a new approach to explore mossy fiber trajectory and branching bifurcation pattern and the quantitative relationship between mossy fibers and granule cell dendrites. CSEM and freeze-fracture method for SEM offered a more detailed in-depth, higher resolution image of outer and inner surface organization of mossy fiber glomeruli. TEM, either by ultrathin sections or freeze-etching replicas, was used as complementary technique for proper orientation, comparative purposes and rational identification of pre- and postsynaptic structures. Freeze-etching replicas showed in addition the real extent of glial cell cytoplasm encapsulating the synaptic glomeruli. The integrated microscopy approach offers a new and more comprehensive view of three-dimensional morphology, organization and quantitative aspects of mossy fiber glomeruli.
 ...
PMID:Confocal, scanning and transmission electron microscopic study of cerebellar mossy fiber glomeruli. 1108 14

Double fluorescent labelling of rat cerebellar cortex using antibody to glial fibrillary acidic protein (GFAP) and Alexa fluor conjugates for secondary detection for confocal laser scanning microscope (CLSM), field emission scanning electron microscopy (FESEM) of Rhesus monkey cerebellar cortex, ultrathin sectioning and freeze-etching replica method for transmission electron microscopy of mouse cerebellar cortex have been examined in an attempt to obtain a new and more accurate view of three-dimensional image of Bergmann glial cells (BGC) and their topographic relations in the molecular layer. Intense immunopositive GFAP green staining was observed in the BGC and glial limiting layer. Secondary antibody conjugated with Alexa fluor 488 and Alexa fluor 668-1B4 stained in red capillary endothelial cells and microglial cells. BGC morphology revealed the existence of several cell types or subpopulations of BGC. Bergmann glial fibers, in palisade arrangement, branch and rebranch forming a complex glial network in the molecular layer. Field emission SEM and freeze-fracture SEM method show the SE-I image of high mass dense Bergmann glial cytoplasm ensheathing like a veil the Purkinje cell (PC) soma and dendritric arborization. Bergmann glial fibers appeared completely surrounding individual parallel fibers or parallel fiber bundles, terminal climbing fiber collaterals, basket and stellate cells and capillaries. Freeze-etching direct replicas showed the typical orthogonal arrangement of intramembrane particles, corresponding to the large repertoire of BGC receptors. The study reveals three-dimensional Bergmann glial cells heterogeneity and the complex network formed by Bergmann glial cells in the molecular layer.
 ...
PMID:Correlative microscopy of cerebellar Bergmann glial cells. 1211 73

The potential to use adult Artemia to deliver erythromycin to first-feeding sockeye salmon, Oncorhynchus nerka (Walbaum), was investigated in three trials. In the first trial, first-feeding sockeye were fed live erythromycin enriched adult Artemia or pellets containing equal amounts of erythromycin for 35 days. At the end of the trial, tissue erythromycin concentration of the fish fed the live Artemia was significantly greater (P < 0.05, 25.52 +/- 1.29 microg mL(-1); mean +/- SEM), than the tissue concentration of the fish fed the pellets (0.72 +/- 0.01 microg mL(-1)). In the second trial, first-feeding sockeye were fed either live or freeze-dried bioencapsulated erythromycin (adult Artemia) or pellets containing erythromycin daily for 21 days. Mean daily erythromycin concentration in fish fed the freeze-dried Artemia, live Artemia, or pellets did not differ significantly. In the third trial, apparent erythromycin digestibility was determined. Significantly more (P < 0.05) erythromycin was retained by juvenile sockeye fed freeze-dried bioencapsulated erythromycin (98.3 +/- 1.0%) compared with medicated pellets (89.2 +/- 1.7%). Uptake of bioencapsulated erythromycin from adult Artemia (live or freeze-dried) appears to be greater than uptake from pellets. Freeze-dried and live Artemia were equally effective at delivery suggesting enriched freeze-dried adult Artemia could be produced into a highly palatable, consistent, off-the-shelf product.
 ...
PMID:Uptake of erythromycin by first-feeding sockeye salmon, Oncorhynchus nerka (Walbaum), fed live or freeze-dried enriched adult Artemia or medicated pellets. 1296 36

Polymer and particle adsorption at the polydimethylsiloxane (PDMS) droplet-water interface has been investigated. Adsorption isotherms and adsorbed layer structure are reported for a range of PEO-PPO-PEO block copolymers, and hydrophilic and hydrophobic silica "nanoparticles". The influence of solution conditions on the adsorption behaviour has indicated the thermodynamics of polymer-droplet and particle-droplet interactions. The influence of droplet cross-linking (deformability) has indicated the role of interfacial penetration in controlling adsorption at the droplet-water interface. The plateau adsorbed amount (Gamma(max)) and adsorbed layer thickness (delta(max)) of PEO-PPO-PEO copolymers are dependent on the copolymer structure and the level of cross-linking within droplets. For a wide range of copolymer structures, Gamma(max) values are in the range 2 to 20 mg m(-2). For delta(max), values range from 2 to 20 nm and are directly proportional to the PEO block length. Droplet cross-linking significantly reduces Gamma and delta values; this is considered to be due to the influence of interfacial penetrability on the adsorbed copolymer conformation. Hydrophilic silica particles adsorb onto PDMS droplets with plateau surface coverages that correspond to their hard sphere radius+double layer thickness, i.e. lateral silica-silica interactions control particle packing. Free energies of adsorption (DeltaG(ads)) are concurrent with a physical adsorption mechanism. Surface coverages, DeltaG(ads) and particle packing at the interface are only weakly influenced by pH, but are significantly influenced by salt addition. Droplet cross-linking reduced particle adsorption only at higher salt concentrations; this was attributed to the increased likelihood of silica particles wetting PDMS. Freeze fracture SEM revealed that individual silica particles are adsorbed at the droplet interface with negligible interfacial aggregation. Densely packed adsorbed particle layers are only observed when the double layer thickness is a few nanometers. Adsorption of hydrophobic particles at the PDMS droplet-water interface is more pronounced (greater adsorbed amounts and DeltaG(ads) values) than for hydrophilic particles and displays a pH dependency in line with 'DLVO behaviour'. The surface coverage values correspond to multiple close packed layers and are significantly influenced by droplet cross-linking, conferring extensive interfacial penetration (confirmed by SEM). Densely packed adsorbed particle layers with interfacial aggregation are observed over a wide range of solution conditions. Interfacial particle saturation occurred at a salt concentration two orders of magnitude less than the critical coagulation concentration (ccc) for silica in water. This phenomenon was observed for both liquid and cross-linked PDMS droplets indicating that particle interaction through the water phase plays a decisive role in particle packing at the interface. SEM indicated the presence of a rigid interfacial crust layer at the salt concentration corresponding to interfacial saturation and a multi-layered interfacial particle wall at salt concentrations >/= ccc. The PDMS droplets under consideration, having inherent colloid stability in the absence of added stabilisers, are an excellent model system for characterising polymer and particle adsorption at the droplet-water interface. The insight gained concerning adsorption thermodynamics at the droplet-water interface is not available from more conventional emulsions.
 ...
PMID:Polymer and particle adsorption at the PDMS droplet-water interface. 1507 33

Dust is an environmental stressor and can become extensive in agricultural production systems. Thirty-six female, Spanish goats (average BW 21.1 kg, SEM = 1.31; age = 4 mo) were randomly assigned to simulated dust events or no dust, with or without tilmicosin phosphate treatment in a 2 x 2 factorial arrangement of treatments to determine effects on performance, rectal temperature, and leukocyte changes. All goats were fed a standard growing diet (13.6% CP) consisting of 37% roughage and 63% concentrate (DM basis). Feed intake was measured daily, and BW (unshrunk) measured individually every 7 d. The tilmicosin-treated group received tilmicosin phosphate (10 mg/kg BW s.c.) before starting the study. Goats exposed to dust were enclosed as a group inside a canvass tent for 4 h each day and ground feed yard manure dust (mean particle size 100 microm) was aerosolized inside the tent to simulate a dust event. There was one single dust event (Phase I) followed by rectal temperature measurement, and heparinized blood collection for complete cell counts at 0 (pretrial), 4, 12, 20, 44, 68, and 210 h after dust exposure. This was followed by 21 d of chronic dust events (Phase II). The sampling procedures for Phase II were exactly the same as in Phase I, except that samples were obtained daily at 0 (before dust application), 4, 8, and 12 h after each dust event. Dust treatment had no effect (P > 0.05) on feed intake or ADG, but the gain:feed (G:F) ratio was lower (P < 0.05) in the control goats than the dust exposed group. Tilmicosin phosphate-treated goats had a higher (P < 0.05) G:F ratio than untreated goats. Dust exposure increased (P < 0.002), but tilmicosin treatment decreased (P < 0.05) rectal temperature at 4 and 8 h. Dust exposure increased (P < 0.02) blood lymphocyte counts compared with controls. These results suggest that simulated dust events altered rectal temperature and leukocyte counts of goats.
 ...
PMID:Effect of simulated ambient particulate matter exposure on performance, rectal temperature, and leukocytosis of young Spanish goats with or without tilmicosin phosphate. 1508 Mar 45

Cutaneous scarring observed in wounds is, to a significant degree, dependent upon the time it takes for the wounds to heal. Various topical dressings are proposed to influence healing time in donor sites. In this prospective randomized study, we examined the effect of Vaseline gauze (VD; Branolind, Paul Hartmann AG, Germany), Biobrane (BD; Bertek Pharmaceuticals, Inc., Morgantown, WV), an occlusive film dressing Barrier Flex (OD; Moelnlycke Health Care GmbH, Germany), and an equine collagen foil, Tissu Foil E (CD; Baxter, Heidelberg, Germany), on re-epithelialization and scarring in standardized donor site wounds. At 6 months after surgery, donor site scars and normal uninjured mirror sided skin were evaluated in 33 patients using both the Vancouver Scar Scale (VSS) and the cutometer SEM 575 (Courage and Khazaka). The median healing time for OD was 14 days, BD 16 days, CD 19 days, and VD 19 days. The single parameter pliability of the VSS was not significantly different from uninjured skin when all donor site scars were pooled. No difference was found between the four groups. Viscoelastic analysis of all pooled patient data showed a significant difference for Uf (total deformation), Ua (total recovery), Ur (immediate retraction), Ue (immediate distension), Ur/Ue, and Ur/Uf, indicating that donor sites significantly differed from normal uninjured skin. No significant correlation between objective viscoelastic measurements and the subjective pliability assessment of the VSS was found. Viscoelastic differences were greatest in the VD and BD groups. Viscolelastic differences did not significantly correlate with healing time. Various wound dressings had minimal yet significant influence on healing time and scarring. In contrast to the VSS, viscoelastic measurements of skin pliability can objectify scarring when few differences are anticipated.
 ...
PMID:Comparing the Vancouver Scar Scale with the cutometer in the assessment of donor site wounds treated with various dressings in a randomized trial. 1667 5

Biphasic beta-rhenanite (beta-NaCaPO(4))-hydroxyapatite (Ca(10)(PO(4))(6)(OH)(2)) biomaterials were prepared by using a one-pot, solution-based synthesis procedure at the physiological pH of 7.4, followed by low-temperature (300-600 degrees C) calcination in air for 6 h. Calcination was for the sole purpose of crystallization. An aqueous solution of Ca(NO(3))(2). 4H(2)O was rapidly added to a solution of Na(2)HPO(4) and NaHCO(3), followed by immediate removal of gel-like, poorly-crystallized precursor precipitates from the mother liquors of pH 7.4. Freeze-dried precursors were found to be nanosize with an average particle size of 45 nm and a surface area of 128 m(2)/g. Upon calcination in air, precursor powders crystallized into biphasic (60% HA-40% rhenanite) biomaterials, while retaining their submicron particle sizes and high surface areas. beta-rhenanite is a high solubility sodium calcium phosphate phase. Samples were characterized by XRD, FTIR, SEM, TEM, ICP-AES, TG, DTA, DSC, and surface area measurements.
 ...
PMID:A new rhenanite (beta-NaCaPO(4)) and hydroxyapatite biphasic biomaterial for skeletal repair. 1676 21

A method was developed to prepare silk fibroin microspheres using lipid vesicles as templates to efficiently load protein drugs in active form for controlled release. The lipid was subsequently removed by methanol or sodium chloride treatments, resulting in silk microspheres consisting of beta-sheet structure and about 2 mum in diameter. NaCl treated microspheres had smoother surfaces compared to the methanol treatments based on SEM analysis, and both types of microspheres had a mixture of multilamellar and unilamellar structures. A model protein drug, horseradish peroxidase, was encapsulated in the microspheres. Freeze-thaw cycles during preparation led to higher loading of the peroxidase due to improved mixing between the silk and drug, while without this process the drug and silk remained in separate layers or domains in microspheres. This partitioning was determined with fluorescein-labeled silk and rhodamine-labeled dextran. Small molecules such as the enzyme substrate 3,3',5,5'-tetramethylbenzidine, Mw=240 Da, and its oxidized product freely diffused through the MeOH- and NaCl-processed silk microspheres so that enzyme loading and activity could be determined. Enzyme activity was retained during processing and in the final microspheres. The enzyme release profile depended on the NaCl-process used in microsphere preparation. The physically cross-linked beta-sheet structure of silk fibroin and the residual lipids in the microspheres played important roles in controlling enzyme release profiles. The silk microspheres have the potential for diverse applications where controlled protein release from biocompatible, mechanically tough, and slowly biodegradable carriers is desirable.
 ...
PMID:Silk microspheres for encapsulation and controlled release. 1721 36


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>