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At least 397 records · Page 22Linked to original sources
PubMed1994

Survival of allochthonous bacteria in still mineral water bottled in polyvinyl chloride (PVC) and glass.

The mortality of Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae and Pseudomonas aeruginosa, based on the culturability of these bacteria, was assessed in non-carbonated mineral water, bottled in polyvinyl chloride (PVC) containing the indigenous flora, sterile mineral water bottled in PVC, sterile mineral water in glass containers, and sterile tap water in glass containers. There was a general decrease in the culturability of these organisms in the four test waters, except that Ps. aeruginosa grew in sterile tap water. Escherichia coli and Kl. pneumoniae had the highest mortality rates under the conditions tested, while Ent. cloacae had a very low and constant mortality rate that would have resulted in the persistence of this organism in mineral water for a long period of time. After a sharp initial decrease in culturability, Ps. aeruginosa also had a very low mortality rate in mineral water bottled in PVC.

Enterobacter cloacae↗
PubMed1986

Ethylene chlorohydrin determination in ethylene oxide sterilized polyvinyl chloride tubing.

A convenient rapid gas-chromatographic method is described for the quantitative determination of ethylene chlorohydrin. The method reported herein extracts the ethylene chlorohydrin with water. The method is simple and offers advantages since no elaborate and expensive gas extraction apparatus is required. The ethylene chlorohydrin levels in five different sterilized polyvinyl chloride samples were found to vary between 5 and 25 ppm. The effect of resterilization with ethylene oxide was investigated and was found to produce less ethylene chlorohydrin.

Chlorohydrins↗
PubMed1992

Sorption studies of dipotassium clorazepate salt (Tranxène) and midazolam hydrochloride (Hypnovel) in polyvinyl chloride and glass infusion containers.

The compatibilities of dipotassium clorazepate and midazolam hydrochloride with polyvinyl chloride (PVC) bags have been studied and compared with those observed with glass flasks. At room temperature, dipotassium clorazepate showed chemical instability which was independent of the container. At 4 degrees C, dipotassium clorazepate showed no decrease in concentration over 12 h, both in 5% dextrose solution and 0.9% sodium chloride solutions. When stored for longer periods of up to 72 h, a slight decrease not exceeding 5% was observed. The compatibility of midazolam with the PVC bags was found to be good at room temperature. It was slightly better in 5% dextrose solution than in 0.9% sodium chloride solution. High sorption of the drug was observed at pH 7.0 when the primary ring structure is maintained. The results make it possible for the hospital pharmacist to prepare dipotassium chlorazepate salt and midazolam admixtures up to 3 days before administration, provided the former are stocked in a refrigerator and the latter are prepared in dextrose isotonic solutions.

Chemistry, Pharmaceutical↗
PubMed1981

Polyvinyl alcohol coating: an improvement of the freeze-fracture technique.

A modification of the freeze-fracture technique, involving the coating of tissues with polyvinyl alcohol (Vinol) prior to freezing, is described. This results in substantial improvements over the more conventional method in which material is cryoprotected and frozen in buffered glycerol alone. The high vacuum is produced more rapidly and can be better than in the absence of vinol and the speed of replica recuperation is greatly increased.

Erythrocyte Membrane↗
PubMed1991

Storage of platelets in a new plastic container. Polyvinyl chloride plasticized with butyryl-n-trihexyl citrate.

The effect of storage of platelets in a new polyvinyl chloride (PVC) plastic material with a butyryl-n-trihexyl citrate (BTHC) plasticizer (PL 2209) was evaluated. The PL 1240 container, i.e. PVC plastic with a different plasticizer, tri-(ethylhexyl)-tri-mellitate, was used as a reference. Measurements of pH, pO2, pCO2, glucose, lactate, adenosine triphosphate, total adenine nucleotide content, lactate dehydrogenase and platelet factor 4 (PF4) were made during 5 days of storage. Similar results were noted comparing PL 2209 and PL 1240. Differences in pO2 and pCO2 indicate greater gas permeability in PL 2209 than in PL 1240. Significantly higher PF4 levels were found in PL 2209, but the difference could not be attributed to the PL 2209 container itself. Paired autologous reinfusion studies (111Indium) of 6 normal donors gave mean recovery values after 5-day storage of 41.1 +/- 7.4% (PL 2209) and 45.5 +/- 7.7% (PL 1240), t1/2 66 +/- 13 and 75 +/- 5 h, survival time (linear model) 6.3 +/- 1.0 and 6.8 +/- 0.7 and survival time (multiple-hit model) 6.0 +/- 0.7 and 6.5 +/- 0.4 days, respectively. Only the difference in survival time (multiple-hit) was significantly higher in PL 1240. The corrected count increments at 12-24 h following transfusion were 13,300 +/- 10,800 (PL 2209) and 13,600 +/- 11,600 (PL 1240) with no statistically significant difference found. These results indicate PL 2209 as an equivalent alternative to PL 1240 for the 5-day storage of platelets.

Blood Component Transfusion↗
PubMed1995

A comparative study of platelets stored in polyvinyl chloride containers plasticised with butyryl trihexyl citrate or triethylhexyl trimellitate.

Platelet concentrates (PCs), stored for 5 days in PL 2209, a new polyvinyl chloride (PVC) storage container plasticised with butyryl trihexyl citrate, were compared with those stored in PL 1240, a PVC platelet container plasticised with triethylhexyl trimellitate. In part 1 of the study, pooled platelet-rich plasma (PRP) was aliquoted into each type of pack and pH, pCO2, pO2, hypotonic shock response, aggregation responses, lactate, glucose and ATP concentrations, and lactate dehydrogenase and beta-thromboglobulin release were compared at days 1, 3 and 5. In part 2, 12 volunteers gave a unit of blood on two separate occasions and PCs produced by the PRP method were stored in PL 2209 or PL 1240 for 5 days before autologous reinfusion of a 111In-labelled sample. In vitro results demonstrated that PL 2209 was more gas permeable than PL 1240. In part 2 of the study, at day 5, pCO2 was 3.13 +/- 0.62 versus 5.14 +/- 0.69 (p < 0.001), whilst pO2 was not significantly different for PL 2209 versus PL 1240, respectively. pH was better maintained in PL 2209 than in PL 1240 (7.38 +/- 0.13 vs. 7.24 +/- 0.10, respectively, p < 0.01) after storage for 5 days. These results were confirmed by those from part 1. In vivo data were similar for PC stored in the two plastics with a multiple-hit recovery of 40.9 +/- 12.1% for PL 2209 and 37.4 +/- 11.3% for PL 1240, and a multiple-hit survival of 4.89 +/- 1.20 days and 5.28 +/- 2.06 days for PL 2209 and PL 1240, respectively. gamma-Camera imaging of volunteers showed similar biodistribution of radiolabelled platelets stored in each container. These results demonstrate that PL 2209 is a suitable container for storage of PCs for 5 days.

Benzoates↗
PubMed2005

Biodesulfurization using Pseudomonas delafieldii in magnetic polyvinyl alcohol beads.

AIMS: To immobilize Pseudomonas delafieldii R-8 cells in magnetic polyvinyl alcohol (PVA) beads for biodesulfurization. METHODS AND RESULTS: Magnetic PVA beads were prepared by a freezing-thawing technique under liquid nitrogen. The beads have distinct super-paramagnetic properties and their saturation magnetization is 8.02 emu g(-1). The desulfurization rate of the immobilized cells could reach 40.2 mmol kg(-1) h(-1). Desulfurization patterns of dibenzothiophene in model oil with the immobilized and free cells were represented by the Michaelis-Menten equation. The Michaelis constant for both immobilized and free cells was 1.3 mmol l(-1). CONCLUSIONS: The cells immobilized in magnetic PVA beads could be stably stored and be repeatedly used over 12 times for biodesulfurization. The immobilized cells could be easily separated by magnetic field. SIGNIFICANCE AND IMPACT OF THE STUDY: Magnetic PVA beads are easy to prepare. The immobilization process in the paper is to increase the efficiency of cells and to decrease the cost of operations.

Bacterial Adhesion↗
PubMed2004

Composite device for attachment of polyvinyl alcohol-hydrogel to underlying bone.

Polyvinyl alcohol-hydrogels (PVA-H) have been specifically proposed as promising prosthetic biomaterials because of their excellent mechanical properties and biocompatibility. However, it is very difficult to obtain stable long-term fixation of implanted PVA-H and this problem is the key point to be solved in the further development of PVA-H in biomedical applications more widely in various fields. Orthopedic implants using PVA-H have been developed and in the process this problem was solved using a composite device. This device consists of PVA-H and a titanium fiber mesh (TFM) as a porous tissue-ingrowth material. In the present study, the mechanical properties of this composite device produced using a new improved production method (injection molding) were investigated and animal experiments for in vivo evaluation were performed. In vitro tests showed that the shear strength at the interface of the PVA-H and TFM, and the mechanical properties of PVA-H itself were promising. Moreover, the histological appearance of the composite device implant in vivo showed abundant bone ingrowth into the deep pore spaces of TFM, which indicated that this device attached firmly to the adjacent bone. These results indicated this composite device prepared by this new method can supply firm attachment of PVA-H onto underlying bone, and that it will be available for various biomedical applications using PVA-H.

Animals↗
PubMed1993

Modified polyvinyl alcohol-benzoporphyrin derivative conjugates as phototoxic agents.

Photosensitizing and biodistribution characteristics of a photosensitizer (benzoporphyrin derivative, monoacid ring A; BPD) conjugated to a macromolecule (modified polyvinyl alcohol; M-PVA, molecular weight = 10,000) were tested in vitro and in vivo. Modified PVA was loaded with BPD at molar ratios 1:12, 1:25, 1:50, 1:75 and 1:100. Most of the work was carried out with a conjugate having a 1:25 molar ratio. In vitro photosensitization was tested using A549 (human lung carcinoma), A432 (human epidermoid carcinoma) and P815 (mastocytoma of DBA/2 mice) cell lines. Photosensitization of M1 (rhabdomyosarcoma of DBA/2 mice) tumors was tested in an in vivo/in vitro assay, in which tumor-bearing mice were injected intravenously with free or conjugated 3H-BPD and 3 h later light activation of tumor cells was carried out in vitro. Biodistribution studies were carried out using M1 tumor-bearing DBA/2 mice and 3H-BPD either free or conjugated to M-PVA. The results of these studies showed that the conjugation of BPD to M-PVA resulted in the formation of a macromolecular photosensitizer that retained full photosensitizing activity of the photosensitizer molecules and at the same time gained new characteristics, advantageous for photodynamic treatment, especially in vivo. In vitro M-PVA-BPD conjugates were at least as efficient in photosensitization of tumor cells as an equivalent number of free BPD molecules, both in the presence and in the absence of serum. Although the biodistribution was in general comparable to free BPD, the conjugate (1:25) reached slightly higher levels in the blood, kidney, lung and spleen, and lower levels in the liver, brain, skin and muscle in comparison with free BPD.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1977

Treatment of keratoconjunctivitis sicca with liquid paraffin or polyvinyl alcohol in double-blind trial.

Twenty-two eyes affected with keratoconjunctivitis sicca have been subjected to double trials using the double-blind randomized cross-over technique. Polyvinyl alcohol in a 5% concentration improved the condition whereas liquid paraffin aggravated it, as estimated subjectively, and by the measurement of the break up time of the corneal film, and, finally, by the scoring of rose bengal vital staining of exposed cornea and conjunctiva. The conclusion is drawn that oil is contraindicated in keratoconjunctivitis sicca, and that rose bengal scoring (modified Bijsterveld method) is a valuable aid in control of the sicca syndrome.

Adult↗
PubMed1983

Precorneal drainage of polyvinyl alcohol solutions in the rabbit assessed by gamma scintigraphy.

A method for monitoring the ocular distribution of solutions for ophthalmic use was developed using the technique of gamma scintigraphy. This method was used to monitor the effects of polyvinyl alcohol on the precorneal drainage of [99mTc]pertechnetate in the rabbit. The rate of drainage of solutions decreased on addition of PVA and precorneal residence of the marker was significantly prolonged, compared with saline controls, at a PVA concentration of 5% W/V. Increases in the activity in the inner canthal region mirrored the decrease in corneal counts. The method has a more general application for the study of ophthalmic formulations and devices in larger mammals and in man.

Animals↗
PubMed1990

Design of a polyvinyl alcohol hydrogen containing phospholipid as controlled-release vehicle for rectal administration of (+/-)-propranolol HCl.

Polyvinyl alcohol hydrogels which contained phospholipid, egg yolk lecithin or hydrogenated soya lecithin were designed as a transrectal delivery system for propranolol hydrochloride. The hydrogel preparations containing phospholipid were prepared by a low-temperature crystallization method. The release profile of propranolol from hydrogel preparations containing phospholipid complied with Fickian diffusion (Higuchi model). The release of propranolol from the hydrogel preparation decreased with higher contents of phospholipid (approximately 2% w/w). In rats plasma concentrations of propranolol after rectal administration of hydrogel preparations containing phospholipid (1 and 2% w/w) were prolonged compared with those of rats receiving preparations without phospholipid.

Administration, Rectal↗
PubMed1993

Controlled release of oral drugs from cross-linked polyvinyl alcohol microspheres.

A new technique for the preparation of cross-linked polyvinyl alcohol (PVA) microspheres containing various drugs is described. An aqueous solution of PVA containing various concentrations of glutaraldehyde was dispersed as droplets in liquid paraffin using a suitable stabilizing agent. Cross-linking of PVA droplets with glutaraldehyde was induced by an acid catalyst (HCl) which was produced by the addition of small quantities of benzoyl chloride into the dispersion medium. Microspheres containing drugs such as aspirin, griseofulvin and nicotinic acid were prepared by carrying out the cross-linking reaction in the presence of such drugs. The drug release studies were carried out in simulated gastric and intestinal fluids without enzymes at 37 degrees C. It was observed that increase in the cross-linking density of the microspheres reduced the drug release rate considerably, suggesting that the release profiles could be controlled by changing the cross-linking density. It was also observed that a higher rate of release was obtained from smaller beads.

Aspirin↗
PubMed1983

Properties and roles of bacterial symbionts of polyvinyl alcohol-utilizing mixed cultures.

From several polyvinyl alcohol (PVA)-utilizing mixed cultures, two component bacterial strains essential for PVA utilization were isolated, and their properties and roles in PVA utilization were studied. Each pair of essential component strains consisted of a type I strain, which produced a PVA-degrading enzyme and constituted the predominant population of the mixed culture in PVA, and a type II strain, which produced a certain growth stimulant for the former strain. All of the type I strains were taxonomically identical and assigned as Pseudomonas sp. In contrast, type II strains were taxonomically different from each other, belonging to Pseudomonas spp. and Alcaligenes sp. PVA utilization occurred in each mixed culture of a type I strain with Pseudomonas putida VM15A as a substitute for the type II strain of the original pair and also in each mixed culture of a type II strain with Pseudomonas sp. VM15C. The growth rates of these substituted, mixed cultures differed from each other.

Alcaligenes↗
PubMed1999

Plasticizers increase adhesion of the deteriogenic fungus Aureobasidium pullulans to polyvinyl chloride.

Initial adhesion of fungi to plasticized polyvinyl chloride (pPVC) may determine subsequent colonization and biodeterioration processes. The deteriogenic fungus Aureobasidium pullulans was used to investigate the physicochemical nature of adhesion to both unplasticized PVC (uPVC) and pPVC containing the plasticizers dioctyl phthalate (DOP) and dioctyl adipate (DOA). A quantitative adhesion assay using image analysis identified fundamental differences in the mechanism of adhesion of A. pullulans blastospores to these substrata. Adhesion to pPVC was greater than that to uPVC by a maximum of 280% after a 4-h incubation with 10(8) blastospores ml(-1). That plasticizers enhance adhesion to PVC was confirmed by incorporating a dispersion of both DOA and DOP into the blastospore suspension. Adhesion to uPVC was increased by up to 308% in the presence of the dispersed plasticizers. Hydrophobic interactions were found to dominate adhesion to uPVC because (i) a strong positive correlation was observed between substratum hydrophobicity (measured by using a dynamic contact angle analyzer) and adhesion to a range of unplasticized polymers including uPVC, and (ii) neither the pH nor the electrolyte concentration of the suspension buffer, both of which influence electrostatic interactions, affected adhesion to uPVC. In contrast, adhesion to pPVC is principally controlled by electrostatic interactions. Enhanced adhesion to pPVC occurred despite a relative reduction of 13 degrees in the water contact angle of pPVC compared to that of uPVC. Furthermore, adhesion to pPVC was strongly dependent on both the pH and electrolyte concentration of the suspension medium, reaching maximum levels at pH 8 and with an electrolyte concentration of 10 mM NaCl. Plasticization with DOP and DOA therefore increases adhesion of A. pullulans blastospores to pPVC through an interaction mediated by electrostatic forces.

Ascomycota↗
PubMed2001

Biosorption of copper by a bacterial biofilm on a flexible polyvinyl chloride conduit.

Inexpensive technologies with less-than-optimal efficiencies as a strategy for countering economic restraints to pollution control have been evaluated by using a laboratory-scale biotreatment process for copper-containing effluent. Economizing measures include the use of polyvinyl chloride (PVC) cylinders fashioned from commercially available flexible PVC conduit to support a biofilm that was cultured in an inexpensive medium prepared in wastewater. The biofilm was challenged by aqueous copper solution in a bioreactor and subsequently analyzed under a scanning electron microscope with energy-dispersive X-ray microanalysis.

Biofilms↗
PubMed2004

Intracellular proliferation of Legionella pneumophila in Hartmannella vermiformis in aquatic biofilms grown on plasticized polyvinyl chloride.

The need for protozoa for the proliferation of Legionella pneumophila in aquatic habitats is still not fully understood and is even questioned by some investigators. This study shows the in vivo growth of L. pneumophila in protozoa in aquatic biofilms developing at high concentrations on plasticized polyvinyl chloride in a batch system with autoclaved tap water. The inoculum, a mixed microbial community including indigenous L. pneumophila originating from a tap water system, was added in an unfiltered as well as filtered (cellulose nitrate, 3.0-microm pore size) state. Both the attached and suspended biomasses were examined for their total amounts of ATP, for culturable L. pneumophila, and for their concentrations of protozoa. L. pneumophila grew to high numbers (6.3 log CFU/cm2) only in flasks with an unfiltered inoculum. Filtration obviously removed the growth-supporting factor, but it did not affect biofilm formation, as determined by measuring ATP. Cultivation, direct counting, and 18S ribosomal DNA-targeted PCR with subsequent sequencing revealed the presence of Hartmannella vermiformis in all flasks in which L. pneumophila multiplied and also when cycloheximide had been added. Fluorescent in situ hybridization clearly demonstrated the intracellular growth of L. pneumophila in trophozoites of H. vermiformis, with 25.9% +/- 10.5% of the trophozoites containing L. pneumophila on day 10 and >90% containing L. pneumophila on day 14. Calculations confirmed that intracellular growth was most likely the only way for L. pneumophila to proliferate within the biofilm. Higher biofilm concentrations, measured as amounts of ATP, gave higher L. pneumophila concentrations, and therefore the growth of L. pneumophila within engineered water systems can be limited by controlling biofilm formation.

Animals↗