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At least 703 records · Page 39Linked to original sources
PubMed1975

Coated versus non-Proplast-coated endosseous blade-vent dental implants.

In order to determine the efficacy of applying Proplast to dental endosseous bladevent implants, this material was coated on half of sixteen such implants which were bilaterally placed in the mandibles of eight rhesus monkeys. No difference in the clinical acceptability could be ascertained between the two groups. Histologic examination revealed a loose connective tissue layer around the noncoated implants which was not evident around the coated ones.

Alveolar Process↗
PubMed1980

A pvdf membrane hydrophone for operation in the range 0.5 Mhz to 15 Mhz.

A new form of hydrophone for measuring the spatial and temporal distributions of pressure within the fields from medical ultrasonic equipment is described. The device comprises an acoustically transparent plastic membrane with a small, central region activated to provide a freely-suspended piezoelectric element. This form of detector offers several advantages over conventional hydrophone probes employing ceramic elements, in particular a flat frequency response. The performance characteristics of a prototype membrane hydrophone and some possible developments and applications are described.

Calibration↗
PubMed1990

Multimeric analysis of von Willebrand factor by molecular sieving electrophoresis in sodium dodecyl sulphate agarose gel.

We report the development and optimisation of an agarose gel electrophoretic method for the separation and detection of von Willebrand Factor (vWF) multimers. The method has been specifically developed for use in the clinical evaluation and classification of patients with von Willebrand's Disease (vWD) and clearly shows structural multimer abnormalities associated with the bleeding diathesis of this inherited bleeding disorder.

Biopolymers↗
PubMed1991

Adhesion and growth of cultured human endothelial cells on perfluorosulphonate: role of vitronectin and fibronectin in cell attachment.

The suitability of neutralized perfluorosulphonic acid (Nafion) as a surface for the attachment and growth of human cells was investigated in tissue culture. Nafion was equivalent to tissue culture polystyrene (TCP), and markedly better than polytetrafluoroethylene (Teflon), for the attachment and growth of human umbilical artery endothelial (HUAE) cells. The attachment and growth of HUAE cells on Fn-coated Nafion was equivalent to that on Fn-coated TCP. The contribution to the attachment and spreading of HUAE cells that is due to adsorption of serum fibronectin (Fn) or vitronectin (Vn) on to the Nafion or TCP was directly tested by selective removal of Fn or Vn from the serum before addition to the culture medium. HUAE cells seeded on to Nafion or TCP in medium depleted of Vn failed to attach and spread on to these surfaces, as measured after 4 or 24 h of culture. HUAE cells seeded in medium depleted of Fn, but containing Vn, attached and spread on to Nafion, albeit to a decreased extent as compared to that in intact serum when measured after 4 h of culture, and there was no effect of depletion of Fn when measured after 24 h of culture. HUAE cells seeded on to TCP in medium depleted of Fn became attached and spread during 4 h of culture. Our results show that Nafion is a suitable polymeric surface for the attachment and growth of human cells, including endothelial cells. For HUAE cells, adsorption on to the surface of an adhesive glycoprotein, such as Vn or Fn, is an essential step for attachment and spreading of the cells onto the Nafion surface.

Biocompatible Materials↗
PubMed1993

Polyphosphazenes as biomaterials: surface modification of poly(bis(trifluoroethoxy)phosphazene) with polyethylene glycols.

Investigations were carried out on the metathetical exchange reaction between the -O-CH2CF3 moieties of poly(bis(trifluoroethoxy)phosphazene) (PTFP), in the state of slightly swollen films, and the alkoxide ions derived from methoxypolyethylene glycol (MPEG) of molecular mass ranging from 350 to 5000 g/mol. The substitution of these hydrophilic chains, mostly confined to thin surface layers, was revealed by means of optical microscopy and scanning electron microscopy observations, surface elemental analysis by energy-dispersive X-ray analysis (EDXA), FTIR-ATR analysis and water contact angle measurements. The surface biocompatibility was enhanced in all cases, whilst the mechanical properties of the original PTFP films were substantially retained in the modified samples exhibiting low substitutions. Such samples were obtained especially when the metathetical reaction was carried out with MPEG5000.

Animals↗
PubMed1991

Transfer of silver-stained proteins from polyacrylamide gels to polyvinylidene difluoride membranes.

We have developed a method to transfer proteins from a silver-stained polyacrylamide gel to a polyvinylidene difluoride (Immobilon-P) transfer membrane (Millipore, Bedford, MA). If the silver stained gels are rinsed in 2 x SDS Laemmli sample buffer prior to transfer, almost all proteins can be transferred comparably to non-stained controls. Some proteins stained with silver can be directly transfer, almost all proteins can be transferred comparably to non-stained controls. Some proteins stained with silver can be directly transferred to a single sheet of Immobilon-P without a prior rinse in sample buffer. Most important in the Western blot the antigenicity of the transferred protein is retained in either way. The method described is simple, inexpensive and versatile. A slight modification of the technique permits one to extract minor proteins, or detect their antigenic activities, without contamination of contiguous proteins.

Blotting, Western↗
PubMed1996

Sensitive detection of metallothioneins-1, -2 and -3 in tissue homogenates by immunoblotting: a method for enhanced membrane transfer and retention.

Standard immunoblotting procedures were unable to detect metallothioneins-1 and 2 (MT-1, MT-2) and metallothionein-3 (MT-3)/growth inhibitory factor (GIF) in unfractionated brain homogenates. We have developed a novel process which involves the inclusion of 2 mM CaCl2 in electrophoretic transfer buffers and glutaraldehyde fixation following transfer to either nitrocellulose or polyvinylidene difluoride (PVDF) membranes. Using commercial MT antibodies and a specific MT-3 polyclonal antibody raised in our laboratory, we have been able to detect all three MTs on both membrane types with a detection limit of approx. 10 ng for MT-1 and MT-2. Nitrocellulose membrane pore size had no noticeable effect on detection sensitivity. These modifications enable more sensitive MT detection than previously described blotting methods. In addition, this technique eliminates the need for indirect monitoring approaches and simplifies quantification since sample fractionation or enrichment are not required.

Animals↗
PubMed1990

Interference by DOPAC and ascorbate during attempts to measure drug-induced changes in neostriatal dopamine with Nafion-coated, carbon-fiber electrodes.

The selectivity of Nafion-coated, carbon-fiber electrodes was evaluated for the voltammetric detection of dopamine in the presence of 3,4-dihydroxyphenylacetic acid (DOPAC) and ascorbate, which are interferant anions in the brain. Nafion coating was applied to both polished carbon-disk electrodes and electrochemically modified electrodes. During in vitro testing, polished disk electrodes showed the greatest selectivity for dopamine at the fastest scan rate tested (300 V s-1), but the drift in signal made slow changes in dopamine difficult to determine. Electrochemically modified electrodes already provide an ascorbate wave distinct from that for dopamine, but Nafion coating actually decreased dopamine selectivity with respect to DOPAC. In vivo testing was carried out in the neostriatum of urethane-anesthetized rats in response to drug- or stimulation-induced increases in dopamine transmission. Administration of haloperidol (0.5 mg kg-1) followed by GBR 12909 (20 mg kg-1), which is known to cause a 10-fold increase in extracellular dopamine, failed to produce a selective signal for dopamine when measured voltammetrically. Comparable results were obtained following administration of amphetamine (2.5 mg kg-1), which also increases dopamine overflow. Voltammetric detection of dopamine was possible, however, during electrical stimulation of dopaminergic afferents in the medial forebrain bundle. Thus, voltammetry with Nafion-coated electrodes is best suited to the measurement of transient changes in extracellular dopamine rather than the relatively prolonged changes in dopamine overflow produced by various drugs.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1991

Detection of double-stranded RNA by ELISA and dot immunobinding assay using an antiserum to synthetic polynucleotides.

An antiserum against polyinosinic-polycytidylic acid (In-Cn) was used to detect double-stranded RNA (dsRNA) by several serological techniques. DsRNA was readily detected by indirect ELISA (ELISA-I) and dot immunobinding assay (DIA). Addition of the antigen to poly-L-lysine-precoated plates and blocking with uncreamed milk powder allowed detection levels of 100 pg.ml-1 In-Cn by ELISA-I. Concentrations as low as 1 ng.ml-1 were detected by DIA using polyvinyliden difluoride (PVDF) membranes. Detection capacity with nitrocellulose membranes was 1000 times lower than with PVDF. ELISA-I and DIA enabled detection of dsRNA in enriched fractions from cucumber mosaic virus (CMV)- and citrus tristeza virus (CTV)-infected plants and from virus-infected Penicillium chrysogenum mycelium. These techniques showed similar or higher sensitivity for detection of dsRNA than separation by polyacrylamide gel electrophoresis and silver staining.

Antibodies↗
PubMed1991

Comparison of Immobilon-N membrane and other membranes for the detection of HIV-1 genome in high risk patients using PCR.

The polymerase chain reaction (PCR) was used for detection of the HIV-1 genome from the peripheral blood lymphocytes of high risk patients. The gag regions of HIV-1 (SK38-SK39) were chosen to amplify viral DNA and the amplified products were spotted onto membrane filters and hybridized with a 32P-labeled SK19 probe. Nitrocellulose, nylon and polyvinylidene difluoride (PVDF) membrane filters were used and compared in dot-blot hybridization. PVDF (Immobilon-N, trade name) filter membranes were demonstrated to be the best membranes on the basis of hybridization data and showed a stronger signal on autoradiograms than the other two types (nitrocellulose and nylon).

Collodion↗
PubMed1995

A simple imprint-hybridization method for detection of viroids.

An imprint-hybridization method has been designed to simplify the processing of samples during routine viroid indexing. The method requires minimal sample manipulation and has been evaluated for detection of viroids in 11 viroid-host combinations including 4 viroids (CEVd, CSVd, HSVd, ASBVd) and 7 hosts (chrysanthemum, citron, cucumber, Gynura, tomato, peach and avocado). The method is fast and sensitive, and provides additional information on the sites of viroid accumulation.

In Situ Hybridization↗