Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “POLYVINYLS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources
PubMed1984

[Health status of the workers of a polyvinyl chloride (PVC) processing plant. III. State of the respiratory tract, immunoglobulins and NBT test].

255 workers processing polyvinyl chloride were examined. All of them underwent spirometric and polycardiographic tests and determination of phagocytic activity of granulocytes, the level of serum albumins and its fractions, and the level of immunoglobulins--IgA, IgG and IgM. The results were compared with the data from healthy non-exposed subjects. It was found that hazards resulting from polyvinyl chloride processing induce slight disturbances in lungs ventilating capacity and inhibit phagocytic activity of granulocytes.

Air Pollutants, Occupational↗
PubMed1981

Insulin adsorption to polyolefin infusion bottles and polyvinyl chloride administration sets.

The availability of various dosages of insulin from a new collapsible polyolefin bottle fitted with a conventional polyvinyl chloride administration set was studied. Intravenous solutions containing various dosages of insulin (20, 40, 70, and 100 units), to which 125I-labeled insulin was added, were prepared. Solutions were mixed and delivered at a maintained flow rate of 125 ml/hour. Effluents were collected at 15, 30, 45, and 60 minutes and then at hourly intervals up to seven hours. One-milliliter samples were drawn from the end of the administration set at the end of each interval, and the level of radioactivity in the sample was measured. Greater percentages of binding occurred at the lower levels of insulin added. Saturation limits of 7.8, 2.7, and 5.4 units were found for the system, administration set, and bottle, respectively. Adsorption values for this bottle were less than that found in another study for polyvinyl chloride.

Adsorption↗
PubMed1978

Surface morphology of polyvinyl chloride and silicone elastomer umbilical artery catheters by scanning electron microscopy.

The surface features of a new silicone elastomer umbilical artery catheter have been defined by scanning electron microscopy and compared with those of a standard polyvinyl chloride catheter. Little difference was noted in the surfaces of the catheter materials themselves, but the radiopaque material used to render the catheters visible by x-ray resulted in a considerable difference in the overall smoothness. The polyvinyl chloride catheter's marker was in the form of a wide, rough band extending the length of the tubing whereas the marker particles of the silicone elastomer were dispersed, more uniform in size, and resulted in less overall irregularity of the surface.

Catheterization↗
PubMed1981

Interactions between drugs and polyvinyl chloride infusion bags.

Forty-six injectable drug products, many of which are administered by i.v. infusion, were studied for loss from aqueous solutions stored in polyvinyl chloride infusion bags for various periods of time. The polyvinyl bags were stored in the dark at room temperature for up to three months. Drugs stored in glass vials served as controls. The solutions were assayed spectrophotometrically at regular intervals. The effects of drug concentration and pH on the loss of drug from solution were studied. Octanol-water partition coefficients were used as a gauge of lipid solubility of the drugs. Five of the drug products-clomethiazole edisylate, diazepam, hydralazine hydrochloride, thiopental sodium, and warfarin sodium-were found to be lost to a substantial extent after one week. For all drugs studied, the effects of the initial concentration on drug loss varied. The amount of drug lost over a given time was a function of the pH of the solution. The main physico-chemical determinants controlling drug sorption appeared to be the extent of ionization and the lipid solubility of the drug. For most of the drugs studied, minimal losses from the aqueous solutions were observed over short periods of storage time. Disappearance was slow and time dependent, indicating a diffusion-controlled sorption process. The losses of clomethiazole edisylate, thiopental sodium, and diazepam may be clinically important.

Drug Packaging↗
PubMed1991

Gel electrophoresis of polystyrene particles in glutaraldehyde crosslinked polyvinyl alcohol.

Polystyrene sulfate and carboxylate particles (19-189 nm radius) were subjected to electrophoresis in glutaraldehyde crosslinked polyvinyl alcohol of molecular weight 25.000 and 650.000 Da at various concentrations. The degree of crosslinking is severely limited by the mechanical properties of the gels that deteriorate beyond a glutaraldehyde concentration which decreases with increasing polyvinyl alcohol chain length. The effective fiber radius of the short-chain and long-chain polymer fiber was 45 +/- 25 and 131 +/- 47 nm, respectively. Thus, these media do not significantly exceed the apparent fiber thickness of agarose, are more difficult to prepare--but are well-defined synthetic products rather than natural ones, and have the advantage of carrying no net charge and can therefore be expected to exhibit no electroendosmosis.

Cross-Linking Reagents↗
PubMed2004

Separation of fluorescein isothiocyanate-labeled amines by microchip electrophoresis in uncoated and polyvinyl alcohol-coated glass chips using water and dimethyl sulfoxide as solvents of background electrolyte.

On-chip capillary electrophoresis with uncoated and polyvinyl alcohol-coated glass channels in aqueous and nonaqueous dimethyl sulfoxide (DMSO) background electrolyte (BGE) solutions was applied in the separation of five amines derivatized with fluorescein-5-isothiocyanate. In aqueous BGE at pH 9.2, baseline separation of the analytes was not achieved on uncoated glass chips, but the separation was clearly improved when the chip channels were coated with polyvinyl alcohol (PVA). Separation was successful in nonaqueous DMSO electrolyte solution containing ammonium acetate and sodium methoxide, on both uncoated and PVA-coated glass microchips. The differences in the pK(a) values of analytes were probably amplified in DMSO, and all five analytes were at least partly dissociated and were separated. Because the viscosity of DMSO is higher than that of water, the migration times were longer in DMSO.

Amines↗
PubMed1975

Linear drug release from laminated hydroxypropyl cellulose-polyvinyl acetate films.

Release of drug from a single-layer film containing dispersed drug follows a diffusion-controlled matrix model, where the quantity released per unit area is proportional to the square root of time. The kinetics may be made linear with time (zero order) by laminating a second film without drug to the releasing side of the film with dispersed drug. In this manner, the drug layer serves as a reservoir and controls the duration of drug release, while the nondrug layer functions as a rate-controlling membrane. Zero-order drug release was demonstrated in such laminated films using 18-45 percent pentobarbital, methapyrilene, or salicylic acid contained in hydroxypropyl cellulose as the reservoir layer and mixtures of hydroxypropyl cellulose and polyvinyl acetate as the membrane layer. Inverse relationships between the release rate and membrane thickness and between the logarithm of the rate and the percentage of polyvinyl acetate in the membrane layer were observed. Of the three drugs tested, salicylic acid gave the fastest release rates while pentobarbital gave the slowest.

Acetates↗
PubMedDate not supplied

Histochemical demonstration of creatine kinase activity using polyvinyl alcohol and auxiliary enzymes.

Creatine kinase activity (EC 2.7.3.2.) has been demonstrated in myocardium and skeletal muscle from rats by a method based on the incubation of cryostat sections with a polyvinyl alcohol-containing medium and the use of auxiliary enzymes. Hexokinase and glucose-6-phosphate dehydrogenase were spread on object glasses before mounting the sections to be incubated. In this way, the auxiliary enzymes were interposed between glass slide and section thus preventing loss of formazan generated within the sections. Creatine kinase activity was found to be localized in finely dispersed form along the myofibrils and as large granules in the sarcoplasm of myocardium and skeletal muscle. The formazan produced specifically by creatine kinase (test minus control), as measured cytophotometrically at 585 nm, was completely inhibited by 2 mM 2,4-dinitrofluorobenzene, a specific inhibitor of creatine kinase activity. The control reaction was unaffected by the inhibitor. The results obtained with the present method are similar to results obtained with the far more complicated semipermeable membrane technique. The introduction of auxiliary enzymes in the polyvinyl alcohol method enables the development of histochemical methods for many enzymes by linking the reactions to a dehydrogenase reaction.

Animals↗
PubMed1988

A quantitative histochemical study of 5'-nucleotidase activity in rat liver using the lead salt method and polyvinyl alcohol.

5'-Nucleotidase (EC 3.1.3.5) activity was demonstrated in cryostat sections of rat liver using the Wachstein-Meisel medium and polyvinyl alcohol as tissue stabilizer. Optimum activity was obtained using an incubation medium containing 5 mM AMP, 10 mM magnesium chloride, 7.2 mM lead nitrate, 0.1 M Tris-maleate buffer, pH 7.2, and 17% (w/v) polyvinyl alcohol (Sigma, type III). The activity was localized at the bile canalicular and sinusoidal side of the plasma membranes of liver parenchymal cells as well as in the plasma membranes of endothelial cells of central veins and in fibroblasts surrounding portal tracts. The reaction was specific for 5'-nucleotidase because it was inhibited by ADP. Alkaline phosphatase did not interfere in the reaction. Cytophotometric analysis revealed a linear relationship between the formation of the final reaction product and incubation times up to 20 min and section thicknesses up to 8 micron. The activity in pericentral zones was 1.35 times the activity in periportal zones. The Michaelis constant for AMP was 1.4 mM in pericentral zones and 0.8 mM in periportal zones, suggesting that the bile canalicular and sinusoidal enzymes differ in their kinetic characteristics.

5'-Nucleotidase↗
PubMed1990

Comparison of clonazepam sorption to polyvinyl chloride-coated and polyethylene-coated tubings.

The sorption of clonazepam to polyvinyl chloride tubing, polyethylene-coated tubing and to a polyethylene syringe was determined. Pumping of clonazepam (5 mg/48 ml) through the polyvinyl chloride tubing with flow rates of 2 ml/h and 4 ml/h resulted in a reduction of the clonazepam concentration to about 40% and 55% of the original strength after 0.6 h, respectively. This value was 55% at a flow rate of 2 ml/h and a clonazepam concentration of 10 mg/48 ml. The effluent clonazepam concentration increased gradually after an infusion period of 1 h. Sorption of clonazepam to the polyethylene syringe and to the tubing coated on the inside with polyethylene does not occur. The use of polyethylene-coated administration sets is recommended for intravenous administration of clonazepam.

Adsorption↗
PubMed1988

Immobilization of a primary amine-containing drug, adriamycin. Coupling to crosslinked polyvinyl alcohol and mechanistic comparison of hydrolytic stability.

Literature reports have described the covalent coupling of the primary amine-containing anticancer drug, adriamycin, to polymeric supports through the amine group on the drug. These reports also have described drug mechanism studies with the immobilized adriamycin, where the release of the drug would undermine the validity of the conclusions. In the present paper, detailed experimental conditions are given for preparation of nonwater-soluble particles of polyvinyl alcohol by crosslinking water-soluble polyvinyl alcohol with 1,4-benzenedicarboxaldehyde, and for activation with cyanuric chloride and covalent attachment of adriamycin. The expected stability of this drug-support linkage against hydrolytic cleavage is compared mechanistically to that expected for less stable coupling through a carbamate linkage or for less stable coupling via an azomethine link.

Doxorubicin↗
PubMed1992

Polyvinyl siloxane impression materials: a review of properties and techniques.

Polyvinyl siloxane impression materials have been shown to have excellent properties as impression materials; however, they are sensitive to manipulative variables. Several methods of using very high viscosity (putty) materials to form "trays" to obtain uniform bulk of the wash impression are described, and the disadvantages of each of these techniques is pointed out. It is recommended that for best results acrylic resin custom trays should be used routinely. The interaction of polyvinyl siloxane materials with latex products is also discussed and problems that this inhibition can cause are stated. Suggestions to avoid this interaction are outlined. One of the disadvantages of the impression materials is that it has a relatively short working time. Refrigerating the material will increase working time without affecting accuracy.

Acrylic Resins↗
PubMed1976

Histocompatibility of polyvinyl acetate, an ingredient of chewing gum.

The histocompatibility of polyvinyl acetate (PVA), an ingredient of chewing gum, was evaluated from both a direct irritant (toxic reaction) and an allergic (antigen-antibody) standpoint. Subcutaneous injections in rats and topical application of hamster pouches were utilized. Polyvinyl acetate was shown to cause a moderate to severe inflammatory reaction when injected subcutaneously, which peaked at day 7 and was minimal at day 42. The histologic appearance of the hamster cheek pouch was not significantly altered by the PVA. Although PVA has been used as a plasticizer in chewing gum, it was not possible to induce any histologic changes in tissues which resembled the specific changes present in atypical gingivostomatitis (plasma-cell gingivostomatitis).

Acetates↗
PubMed1986

Small particle polyvinyl alcohol embolization of cranial lesions with minimal arteriolar-capillary barriers.

Polyvinyl alcohol foam, prepared as small particles measuring 70-150 micron when injected in intracerebral arteries of the rat, adhere to the vascular endothelium, allowing the particles to be captured without necessarily wedging intraluminally. Based on this observation, small particle microembolization was performed in a series of patients who had hypervascular cranial lesions, whose matrices angiographically appeared to have at best minimal arteriolar-capillary barriers. Each case was associated with intracranial dural sinus or cerebral venous drainage. In addition, several lesions had either venous ectasia or venous aneurysms. Symptomatic improvement occurred in all cases without apparent neurologic or pulmonary complications. These examples demonstrate the ability of very small polyvinyl alcohol foam particles to remain within the interstices of vascular lesions that display evidence of only minimal arteriolar-capillary barriers.

Adult↗
PubMed2004

A novel immunosensor based on immobilization of hepatitis B surface antibody on platinum electrode modified colloidal gold and polyvinyl butyral as matrices via electrochemical impedance spectroscopy.

Hepatitis B surface antibody (HBsAb) was immobilized to the surface of platinum electrode modified with colloidal gold and polyvinyl butyral (PVB) as matrices to detect hepatitis B surface antigen (HBsAg) via electrochemical impedance spectroscopy (EIS). The electrochemical measurements of cyclic voltammetry and impedance spectroscopy showed that K(4)[Fe(CN)(6)]/K(3)[Fe(CN)(6)] reactions on the platinum electrode surface were blocked due to the procedures of self-assembly of HBsAb-Au-PVB. The binding of a specific HBsAb to HBsAg recognition layer could be detected by measurements of the impedance change. A new strategy was introduced for improving the sensitivity of impedance measurements via the large specific surface area and high surface free energy of Au nanoparticles and the encapsulated effect of polyvinyl butyral. The results showed that this strategy caused dramatic improvement of the detection sensitivity of HBsAg and had good linear response to detect HBsAg in the range of 20-160 ng.ml(-1) with a detection limit of 7.8 ng.ml(-1). Moreover, the studied immunosensor exhibited high sensitivity and long-term stability.

Biosensing Techniques↗
PubMed2006

Primary study on the assay of superficial hydroxyl group content upon the solid polyvinyl alcohol.

Polyvinyl alcohol is a multipurpose polymer, and there is abundant hydroxyl group on its surface. In this article, we first time attempted to assay the superficial hydroxyl group content on the solid polyvinyl alcohol (PVA-1799) with a degree of polymerization over 1700 and a degree of alcoholysis over 99.0%. The assay was carried out by two different titration systems. The results show: (1) the order of magnitude of superficial hydroxyl group content on its solid surface was about 3.8E-5 mol/cm2 by acylation system with single functional group reagent (acetic anhydride); while (2) the order of magnitude of superficial hydroxyl group content was about 1.4E-7 mol/cm2 by esterification system with bi-functional group reagent (Toluence 2,4-DiIsocyanate, TDI). The results would be useful to provide a quantitative reference when -OH on the solid PVA surface is intended to be utilized for surface modification for some application. Moreover, the results and their difference also offer us the knowledge of the surface modification efficiency.

Acylation↗
PubMed2005

Biological evaluation of a polyvinyl siloxane impression material.

OBJECTIVES: The aim of this study was to determine the irritant properties of a new polyvinyl siloxane impression material (Ghenesil, Lascod-Italy) after single application to intact skin of the rabbit. METHODS: The material was evaluated for primary skin irritation according to the UNI EN ISO 10993-10:1996 using three healthy male New Zealand White rabbits. The back of the animals was clipped free of fur and divided into four sites with the same area 24 h before application of the sample. The material was applied to only two sites; the other two were used as controls. All the sites were covered by gauze and the back of the rabbit was wrapped with a non-occlusive bandage. After 4 h, the bandage and the test material were removed; 1h later the sites were examined for skin irritation and the observation was repeated after 24, 48 and 72 h. The Score of Primary Irritation (SPI) was calculated for each animal and the Primary Irritation Index (PII) was calculated as the arithmetical mean of SPI values. RESULTS: The PII of the test material resulted 0.06. SIGNIFICANCE: Based on present results, it can be concluded that the primary skin irritation of the polyvinyl siloxane impression material tested can be considered negligible.

Animals↗