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PubMedDate not supplied

Relationships between ferruginous bodies and uncoated asbestos fibers in lung tissue.

Tissue was obtained from two American groups. The tissue was defined by ferruginous body levels of either < or = 1000 or > 1000 ferruginous bodies/g dry weight, and tissue was evaluated by light microscopy and analyzed by analytical transmission electron microscopy. Tissue was bleach digested, and uncoated asbestos fibers were classified with respect to type and size. In addition, some ferruginous body cores were analyzed. There was a wide range of uncoated fibers associated with each ferruginous body. A relationship was found between amosite fibers and ferruginous bodies. Other asbestos types were not associated significantly with the development of ferruginous bodies. Uncoated crocidolite fibers were not detected in these samples; this result further emphasizes the under-appreciated exposure of Americans to amosite. The levels of ferruginous bodies in both groups suggest exposures above those expected in the general population. Uncoated chrysotile levels were below the ranges reported previously for some general populations. The data suggest that there is a wide variation in the ratio of uncoated to coated fibers and that the amphibole in the United States is more likely to be amosite than crocidolite.

Aged↗

PubMed2004

Uncoated endocytic vesicles require the unconventional myosin, Myo6, for rapid transport through actin barriers.

After clathrin-mediated endocytosis, clathrin removal yields an uncoated vesicle population primed for fusion with the early endosome. Here we present the first characterization of uncoated vesicles and show that myo6, an unconventional myosin, functions to move these vesicles out of actin-rich regions found in epithelial cells. Time-lapse microscopy revealed that myo6-associated uncoated vesicles were motile and exhibited fusion and stretching events before endosome delivery, processes that were dependent on myo6 motor activity. In the absence of myo6 motor activity, uncoated vesicles remained trapped in the actin mesh, where they exhibited Brownian-like motion. Exit from the actin mesh occurred by a slow diffusion-based mechanism, delaying transferrin trafficking to the early endosome. Expression of a myo6 mutant that bound tightly to F-actin produced immobilized vesicles and blocked trafficking. Depolymerization of the actin cytoskeleton rescued this block and specifically accelerated transferrin delivery to the early endosome without affecting earlier steps in endocytosis. Therefore actin is a physical barrier impeding uncoated vesicle trafficking, and myo6 is recruited to move the vesicles through this barrier for fusion with the early endosome.

Actins↗

PubMed2006

Hydroxyapatite dip coated and uncoated titanium poly-axial pedicle screws: an in vivo bovine model.

STUDY DESIGN: A 1-year-old calf was implanted with titanium pedicle screws either uncoated (n = 7) or coated with hydroxyapatite (n = 7) by the dipping method on the pedicles of vertebrae (t10-l3). OBJECTIVE: To evaluate biomechanical and histomorphologic responses to titanium pedicle screws uncoated and coated with hydroxyapatite. SUMMARY OF BACKGROUND DATA: Failure of fixation caused by loosening of pedicle screws is a problem in spinal surgery. Enhancement of the fixation ability of screws by coating with biocompatible materials may improve prognosis of surgery. METHODS: The calf was euthanized 4 months after implantation for determination of insertion and extraction torques for screws, and histologic and scanning electron microscopic examinations of areas screw embedded. RESULTS: Insertion torques did not differ by the kind of screws (99 +/- 5.7 Ncm). However, extraction torques for screws coated with hydroxyapatite were higher than for screws uncoated (249 vs. 133 Ncm, P < 0.01). As compared with uncoated screws, implanted areas for hydroxyapatite-coated screws were denser, had more cracks, and provided better bonding. Fibrous tissue and new bone formation were observed around the areas of uncoated and hydroxyapatite-coated screws embedded, respectively. CONCLUSIONS: Hydroxyapatite coating of titanium pedicle screws by the dipping method improved fixation and vertebral bone-implant interface, suggesting a decreased risk of a screw-loosening problem.

Animals↗

PubMed1979

Uncoating of adenovirus type 2.

The uncoating of adenovirus type 2 and a temperature-sensitive mutant, tsl, was studied. HEp-2 cells were infected with 32P- OR 125I-labeled purified virions for various lengths of time, and the nuclear and cytoplasmic fractions were analyzed by sucrose gradient velocity sedimentation and sodium dodecyl sulfate-polyacryl-amide gel electrophoresis. Within 1 h of infection, virions were converted into three subviral structures: (1) subviral structures in the cytoplasm with a density greater than virions but which qualitatively still contained all virus polypeptides; (ii) corelike structures associated with both the nuclear and cytoplasmic fractions and composed of viral DNA and polypeptides VIa2, V and PVII; and (iii) putative DNA-terminal protein complexes in the nuclei. The kinetic and compartmentalization studies suggested that the DNA-terminal protein complex is the end product of uncoating. The virions which were synthesized by tsl at the nonpermissive temperature and contained the precursor polypeptides PVI and PVII were found to be blocked in uncoating at the corelike stage. This block in uncoating provides the explanation for the lack of infectivity of these virions. A model for the uncoating of adenovirus is proposed.

Adenoviruses, Human↗

PubMed1980

Isolation and characterization of polyoma uncoating intermediates from the nuclei of infected mouse cells.

A method was developed which enabled the efficient recovery of polyoma uncoating intermediates from the nuclei of infected cells at early times after infection (15 min to 12 h). Cells were infected with radiolabeled virus and lysed with the detergent Nonidet P-40. The nuclei were then collected and sonicated, and the products were analyzed on sucrose gradients. The uncoating intermediate sedimented at 190S and was a viral DNA-protein complex closely associated with a structure of host origin. The host material associated with the 190S uncoating intermediate was determined by polyacrylamide gel electrophoresis and visualized by electron microscopy. The amount of 190S uncoating intermediate found in the nucleus increased with time after infection. The viral DNA was predominantly for I. All of the viral proteins were present in the 190S uncoating intermediate in amounts similar to those found in viral DNA-protein complex cores.

Animals↗

PubMed1994

Protective antibodies inhibit reovirus internalization and uncoating by intracellular proteases.

We identified in vitro correlates of in vivo protection mediated by nonneutralizing antibodies specific for reovirus capsid proteins. We defined mechanisms of antibody action by analyzing monoclonal antibody (MAb) effects at sequential steps in reovirus serotype 3 strain Dearing (T3D) infection of L cells. Two types of experiments showed that protective MAbs specific for the outer capsid proteins sigma 3 or mu 1 inhibited T3D infection independent of effects on binding. First, MAbs which had no effect on T3D binding inhibited T3D growth. Second, MAb-coated T3D attached to L cells did not replicate as efficiently as T3D without bound antibody. We therefore defined sigma 3-specific MAb effects on postbinding steps in T3D infection. T3D coated with MAb sigma 3-10G10 exhibited prolonged sensitivity to growth inhibition by ammonium chloride. Since ammonium chloride inhibits endosomal acidification and proteolytic processing of the T3D capsid, this suggested that MAbs inhibit early steps in T3D infection. This was confirmed by direct demonstration that several sigma 3-specific MAbs inhibited proteolytic uncoating of virions by fibroblasts. We identified two mechanisms for antibody-mediated inhibition of virion uncoating: (i) inhibition of internalization of T3D-MAb complexes bound to the cell surface, and (ii) inhibition of intracellular proteolysis of the T3D capsid. Studies using a cell-free system confirmed that sigma 3-specific MAbs directly block proteolytic uncoating of the T3D virion. In addition, we found that sigma 3-specific MAbs block (and therefore define) two distinct steps in proteolytic uncoating of the reovirion. We conclude that antibodies which are protective in vivo inhibit postbinding events in reovirus infection of permissive cells. Protective antibodies act by inhibiting internalization and intracellular proteolytic uncoating of the virion. Analysis of postbinding mechanisms of MAb action may identify targets for vaccine development and antiviral therapy.

Ammonium Chloride↗

PubMed2001

Tibial implants: biomechanical and histomorphometric studies of hydroxyapatite-coated and uncoated stainless steel and titanium screws in long-term ovariectomized sheep.

This study was designed to evaluate osteointegration of HA-coated and uncoated titanium and stainless steel screws in the cortical bone of long-term (24 months) ovariectomized sheep (OVX group), in comparison with Sham-aged sheep (control group). The screws were tested biomechanically (extraction torque) and histomorphometrically (affinity index: Al) 12 weeks after their implantation in tibial diaphyses. Tibial cortical bone parameters showed significant differences between the groups, showing a reduction of the selected parameters in the OVX group. ANOVA showed significant effects for both material and ovariectomy factors on obtained extraction torque (material: F=159.26, p < 0.0005; ovariectomy: F=20.04, p < 0.0005) and Al data (material: F=8.04, p < 0.001; ovariectomy: F=7, 17, p < 0.05). In both groups the extraction torque for coated screws of both materials was significantly higher than for uncoated screws, and uncoated titanium had a better extraction torque than uncoated stainless steel. In the OVX group, the HA-coated stainless steel and titanium Al data were significantly higher than uncoated Al data. In conclusion, the biomechanical and histomorphological results obtained suggest employing HA-coated screws in the presence of osteopenic cortical bone.

Animals↗

PubMed1998

Comparison of enteric-coated aspirin and uncoated aspirin effect on bleeding time.

Aspirin therapy is an essential part of the drug regimen for patients with acute myocardial infarction (MI), unstable angina, or after coronary angioplasty and coronary stenting. Recognizing this importance, this study sought to compare the bleeding time in two groups of 10 normal volunteers 4 hr after ingestion of either an enteric-coated aspirin or an uncoated aspirin, assuming that a difference between the two groups could be clinically significant. Defining < or = 8 min as normal, 80% of the uncoated group developed abnormal bleeding times, compared to 10% of the enteric-coated group (P < 0.01). The study demonstrates a significant difference between the two types of aspirin preparations on bleeding times in normal individuals. This strongly suggests that some enteric-coated aspirin preparations may not be as effective as uncoated aspirin in acutely decreasing platelet aggregation. Therefore, uncoated aspirin is recommended in the setting of acute MI, unstable angina, or after percutaneous transluminal coronary angioplasty.

Aspirin↗

PubMed2003

Hydrophilic coating aids radial sheath withdrawal and reduces patient discomfort following transradial coronary intervention: a randomized double-blind comparison of coated and uncoated sheaths.

Radial artery spasm may cause severe discomfort during radial artery sheath removal. A hydrophilic-coated sheath may reduce the force required to remove a radial sheath. This force may be quantified using an automatic pullback device (APD). The objective of this study was to assess if a hydrophilic coating reduces the required force and discomfort associated with removal of a radial sheath following transradial coronary intervention. Ninety patients undergoing percutaneous coronary intervention via the radial artery were randomly assigned to two groups receiving either coated or uncoated introducer sheaths. Radifocus Introducer II (Terumo) 25 cm, 6 Fr radial sheaths and sheaths that were identical apart from the presence of the coating were used in all patients. The APD was used for sheath removal at the end of the procedure. Three patients (7%) in the coated group experienced discomfort during automatic sheath removal, compared to 12 patients (27%) in the uncoated group (P = 0.02). The maximum pullback force (MPF) was significantly lower in the coated compared to the uncoated group (0.24 +/- 0.31 vs. 0.44 +/- 0.33 kg; P = 0.003). Similarly, the mean pullback force was significantly lower in the coated group (0.14 +/- 0.23 vs. 0.32 +/- 0.24 kg; P < 0.001). Only one patient (2%) in each group had an MPF greater than 1.0 kg together with clinical evidence of radial artery spasm. Removal of the coated Terumo Radifocus sheath requires less force than an identical uncoated sheath. The coated sheath was also associated with less discomfort for the patient.

Aged↗

PubMed1995

The use of coated and uncoated capillaries for the electrophoretic separation of DNA in dilute polymer solutions.

We show that both uncoated and polyacrylamide-coated capillaries provide separation of large DNA restriction fragments (2.0-23.1 kbp) by capillary electrophoresis in dilute cellulosic polymer solutions. Uncoated capillaries, however, provide significantly better resolution of DNA fragments, particularly when ultra-dilute polymer solutions are used. This is because electroosmotic flow in uncoated capillaries increases the residence time of DNA in the capillary, without significantly contributing to band-broadening. At a given field strength and polymer concentration in the buffer, the electrophoretic mobilities of DNA restriction fragments in coated capillaries are virtually identical to those previously measured in uncoated capillaries. It is concluded that the fused silica surface of the capillary does not play a significant role in the mechanism of DNA separation by capillary electrophoresis in uncrosslinked polymer solutions. Thus, the separation of large DNA which has been observed to occur in ultra-dilute polymer solutions arises primarily from entanglement interactions between the cellulosic polymers and DNA restriction fragments which occur within the bulk of the polymer solution.

Acrylic Resins↗

PubMed2006

CE-LIF analysis of mitochondria using uncoated and dynamically coated capillaries.

This report is the first demonstration of the use of uncoated and dynamically coated capillaries for the separation of individual mitochondria via CE. Currently, the analysis of individual mitochondria relies upon fused-silica capillaries coated with a hydrophilic polymer (e.g. poly(acryloylaminopropanol)), which is used to minimize adsorption to the capillary surface. Both uncoated fused-silica capillaries and 0.2% w/w poly(vinyl alcohol) dynamic coating solutions are used to successfully analyze isolated individual mitochondrial particles using CE-LIF. While it was possible to separate mouse liver mitochondria on an uncoated capillary, rat liver mitochondria proved to have strong adsorption characteristics that only allowed them to be adequately separated with a PVA dynamic coating or a poly(acryloylaminopropanol) (AAP) capillary. The possible causes for this adsorption are analyzed and discussed. This study shows that uncoated and dynamically coated capillaries can be used in place of AAP-coated capillaries to analyze mitochondria and suggests the use of these capillaries for the analysis of other organelles, offering a greatly simplified method for the analysis of individual organelles.

Acrylates↗

PubMed1983

Quantitative histologic evaluation of LTI carbon, carbon-coated aluminum oxide and uncoated aluminum oxide dental implants.

The response of mandibular bone to identical geometry LTI carbon, carbon-coated aluminum oxide, and uncoated aluminum oxide blade-type dental implants in baboons for 2 years was evaluated using histologic, microradiographic, and scanning electron microscopic methods. In addition, a quantitative histologic analysis was performed identifying the type, amount, and distribution of tissue surrounding the dental implant systems. This is the final phase of a study investigating the effect of implant elastic modulus and implant surface chemical composition on the performance of dental implants. Previous studies have utilized clinical and radiographic evaluations, postretrieval mechanical testing, and finite element stress analysis to evaluate the dental implant performance. The results of the histologic study revealed a direct implant-bone interface with no intervening soft tissue in 16 of the 21 implants (76%). A fibrous tissue interface was observed in 5 of 21 implants (24%). Quantitative histologic results for the implants with a direct implant-bone interface showed statistically larger crestal cortical plates (p less than 0.05) and greater area fraction crestal cancellous bone (p less than 0.05) in the LTI carbon implant compared to the carbon-coated and uncoated aluminum oxide implants. The carbon-coated and uncoated aluminum oxide implants demonstrated statistically greater area fraction cancellous bone at the inferior region of the implant (p less than 0.05) and thinned and reduced crestal cortical plates when compared to the LTI carbon implants. The results indicate that significant stress shielding of the crestal bone had occurred with the rigid carbon-coated and uncoated aluminum oxide implants when compared to the LTI carbon implants which had a material elastic modulus similar to cortical bone. Based upon the histologic results, it appears that the LTI carbon implants with the direct implant-bone interface exhibited a greater potential for long-term successful performance compared to the aluminum oxide substrate implants.

Aluminum↗

PubMed1984

Organization and dynamics of lipids in bovine brain coated and uncoated vesicles.

Three characteristics have been demonstrated by the chemical analysis of bovine brain coated vesicles following removal of the coat proteins: a high protein content, a high cholesterol/lipid ratio and a high percentage of phosphatidylethanolamine amongst the phospholipids. The study of lipid bilayer organization and dynamics has been performed using the fluorescent probes pyrene and parinaric acid (cis and trans). This has allowed the study of both lateral mobility and rotational motion in the lipid bilayer of the coated and uncoated vesicles. Lateral mobility in the fluid phase of the lipid is slightly reduced by the presence of the clathrin coat, as indicated by the lower diffusion coefficient of pyrene in coated compared with uncoated vesicles. At all temperatures from 6 degrees to 30 degrees C, solid-phase domains, probed by trans parinaric acid, coexist with fluid-phase domains in the lipid bilayer. The temperature dependence of the parinaric acid lifetimes and of their amplitudes strongly suggests that the solid phase domains decrease in size with temperature, both in coated and uncoated vesicles. However, the difference in the value of the anisotropy at long times (r infinity), between coated and uncoated vesicles (a difference which is more pronounced for cis than for trans parinaric acid), indicates that the presence of the clathrin coat introduces disorder in the surrounding lipids, thus suggesting a possible role of the clathrin in the formation of the pits on the plasma membrane.

Animals↗

PubMed1993

Enhancement of intracellular uncoating of adenovirus in HeLa cells in the presence of benzyl alcohol as a membrane fluidizer.

The early extra- and intra-cellular interaction between adenovirus type 2 and HeLa cells was studied in the presence of benzyl alcohol as a fluidizing agent. The process of virus attachment and internalization were not affected at 5-15 mM of benzyl alcohol at 25 degrees C. Under the same conditions an enhancement by 45% at the most was demonstrated for the cell-mediated virion uncoating. By completely blocking virion internalization with 50 mM azide the uncoating was reduced to 20% of the normal level. The remaining surface-located uncoating was not affected by benzyl alcohol. It was demonstrated that an enhancement of the intracellular virion uncoating was followed by a raised production of the hexon antigen, which was interpreted as an increase in the specific infectivity of the virus.

Adenoviridae↗

PubMed1987

Fusion of negatively charged liposomes with clathrin-uncoated vesicles.

The interaction of lipid vesicles with uncoated vesicles from bovine brain has been studied by fluorescence energy transfer between fluorescent lipid analogs (NBD-PE, Rh-DOPE), by loss of fluorescence self-quenching (NBD-PE, carboxyfluorescein) and by freeze-fracture electron microscopy. The fluorescence techniques monitor the mixing of membranous lipids and the induced release of encapsulated material. The results demonstrate a mixing of the negatively charged lipid (PA, PS) vesicles with the uncoated vesicles. In parallel with the lipid mixing a release of intravesicularly encapsulated material takes place. Lipid vesicles composed of zwitterionic lipids (PC, DOPC, PC:PE) do not specifically interact with uncoated vesicles. The electron micrographs reveal single fusion events. Studies on the kinetics are consistent with a fusional mechanism of the negatively charged lipid vesicles with uncoated vesicles.

Animals↗

PubMed1986

Uncoating ATPase is a member of the 70 kilodalton family of stress proteins.

The synthetic peptide, VGIDLGTTYSC, derived from the heat shock-induced genes human hsp70, Drosophila hsp70, S. cerevisiae YG100, and E. coli dnaK, elicited antibodies that recognized two constitutive proteins in bovine extracts. One of these proteins, 71 kd, has previously been identified as uncoating ATPase, an enzyme that releases clathrin from coated vesicles. This immunological data complemented the result that uncoating ATPase was indistinguishable from the constitutive mammalian 71 kd stress protein by either partial proteolytic mapping or two-dimensional gel analysis. In addition, affinity-purified uncoating ATPase antibodies recognize proteins in yeast identified as the gene products of the heat shock or heat shock cognate genes YG100 and YG102. The results show that uncoating ATPase is a member of the 70 kd heat shock protein family.

Adenosine Diphosphate Ribose↗

PubMed1992

Antibody-mediated uncoating of adenovirus in vitro.

In a virus destabilization assay in vitro it was demonstrated that exposure of adenovirus to proteins will non-specifically protect the virus from being uncoated following transfer to low pH and hypotonic conditions. Such uncoating was also fully inhibited upon pretreatment of virus with 0.05% of the non-ionic detergent polyoxyethylenesorbitan monolaurate (Tween 20). However, in the presence of low concentrations of Tween 20 it was shown that monospecific immunoglobulins, directed against the fiber antigen and polyspecific antibodies produced in response to intact virions, were able to overcome the detergent-protecting effect of uncoating. Immunoglobulins directed towards the remaining outer-capsid components, the hexon, the penton base and the protein IIIa, revealed no such effects. The antifiber-mediated uncoating was paralleled by an aggregation of the virions. The data suggest that the virion-stabilizing effect of salt is enhanced by the hydrophobic action of a non-ionic detergent. Under these conditions the interaction between antifiber antibodies and fibers of the virion will trigger a destabilization of the virion upon transfer to low pH and hypotonic conditions.

Adenoviruses, Human↗

PubMed2002

Hydroxyethylcellulose as an effective polymer network for DNA analysis in uncoated glass microchips: optimization and application to mutation detection via heteroduplex analysis.

The nature of the sieving matrix for DNA fragment separation is of immense importance in capillary and microchip electrophoresis. The chemical nature of the surface of the capillary or microchannel wall is equally as important, particularly with DNA electrophoresis where a substantial electroosmotic flow (EOF) may be detrimental to the separation. Although DNA analysis has been carried out successfully in both coated and uncoated capillaries, analysis of unpurified polymerase chain reaction products has been carried out primarily with covalently coated surfaces, especially with microchip electrophoresis. In this report, double-stranded (ds) DNA fragment analysis using hydroxyethylcellulose (HEC) buffered in 1xTris-borate-EDTA is demonstrated both in uncoated capillaries and in microchips. EOF was suppressed 20% in the presence of 1.5% HEC, and the effectiveness of HEC as a polymer for dsDNA fragment analysis was dependent on the pH, with pH 8.6 being optimal. Using separation efficiency (number of theoretical plates) and resolution to gauge the effectiveness of a variety of polymers for the capillary separation of dsDNA fragments in the size range 60-587bp, HEC was found to be comparable in performance to polydimethylacrylamide (PDMA), and superior to linear polyacrylamide and polyethylene oxide for DNA analysis. With respect to longevity and robust performance, HEC could be used effectively in an uncoated capillary for more than 40 runs and for more than 90 runs (without replenishing the polymer) in an uncoated microchip. Application of the optimized HEC conditions is demonstrated through its ability to facilitate heteroduplex analysis.

Buffers↗