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PubMedDate not supplied

Polyacrylic acid gel in patients with dry eyes: a randomised comparison with polyvinyl alcohol.

PURPOSE: To compare the safety and efficacy of polyacrylic acid 0.2% (PAA) gel and polyvinylalcohol 1.4% (PVA) in the treatment of patients with dry eyes. METHODS: Eighty-nine patients with dry eyes were randomly allocated to treatment with either PAA (48) or PVA (41) in a prospective, investigator-masked study in two centres. The parameters assessed were daily frequency of instillation of the study medications, ocular signs and symptoms, tear film break up time, Schirmer's test values, local tolerance and global assessment of the improvement following treatment. RESULTS: The two groups were similar in patient demographics and study parameters at baseline. The total score of symptoms (gritty or foreign body sensation, burning sensation, dry eye sensation, photophobia, others) and signs (conjunctival hyperaemia, ciliary injection, corneal and conjunctival epithelial staining) was reduced significantly more by treatment with PAA than with PVA at both three and six weeks (p < 0.0001). The daily frequency of instillation of PAA was significantly less than that PVA on 38 of the 41 (93%) study days. Both PAA and PVA were safe and equally well-tolerated except for blurred vision, usually mild and transient, on PAA. On global assessment of the improvement in their dry eye condition, significantly more PAA patients felt better on treatment at six (p = 0.02) weeks compared with those on PVA. CONCLUSIONS: Polyacrylic acid gel was as safe as and more effective than polyvinylalcohol in the treatment of patients with dry eyes.

Acrylic Resins↗
PubMed1996

Improved localization of fluorescent tyramides for fluorescence in situ hybridization using dextran sulfate and polyvinyl alcohol.

Recently, a peroxidase-mediated amplification system has been described for immunofluorescence and fluorescence in situ hybridization studies. It is based on the deposition of hapten- or fluorochrome-labeled tyramide molecules. Although providing a significantly increased detection sensitivity compared to conventional procedures, its localization properties are inferior because of free diffusion of intermediate reaction products before they are immobilized. In enzyme cytochemistry, it is well established that improved localization of enzyme activity can be achieved through the addition of viscosity-increasing polymers to the incubation media. In this study we analyzed the effect of different polymers on the localization sharpness and sensitivity of the tyramide-peroxidase reaction in FISH applications. Significantly improved localization of the fluorescent endproduct was observed using dextran sulfate or polyvinylalcohol (PVA) with, respectively, no or little loss of sensitivity.

Dextran Sulfate↗
PubMed1989

Design of polyvinyl alcohol hydrogel as a controlled-release vehicle for rectal administration of dl-propranolol-HCl and atenolol.

Preparations of beta-blockers, propranolol-HCl and atenolol, in poly(vinyl alcohol) (PVA) hydrogel were designed for the therapeutic treatment of hypertension by transrectal delivery. In vitro release characteristics and plasma drug concentration profiles after rectal administration in rats and dogs were examined. The PVA hydrogels containing beta-blockers were prepared by a low-temperature crystallization method. The release of beta-blockers from hydrogel preparations was consistent with Fickian diffusion (Higuchi model); the drug release versus the square root of release time profile gave a straight line over 60% of the total release process. The release of beta-blockers from hydrogel preparations increased at higher concentrations of PVA in the hydrogel preparations and was not affected by the pH of hydrogel preparations. Plasma concentrations of beta-blockers after rectal administration of hydrogels were higher than those after administration of suppositories (Witepsol H-15) in rats and dogs. The drug plasma concentrations increased at higher concentrations of PVA in hydrogel preparations. In the case of propranolol, which is a hepatic high-clearance drug, area under the blood concentration curve, 0-8 h after rectal administration of a hydrogel preparation (20% w/w PVA, pH 7.0) was 2.16 times and 5.26 times higher than those obtained with Witepsol H-15 suppository and oral administration, respectively. Rectal administration with PVA hydrogels is a favorable route for a hepatic high-clearance drug such as propranolol.

Animals↗
PubMed2005

SPARC-thrombospondin-2-double-null mice exhibit enhanced cutaneous wound healing and increased fibrovascular invasion of subcutaneous polyvinyl alcohol sponges.

Secreted protein acidic and rich in cysteine (SPARC) and thrombospondin-2 (TSP-2) are structurally unrelated matricellular proteins that have important roles in cell-extracellular matrix (ECM) interactions and tissue repair. SPARC-null mice exhibit accelerated wound closure, and TSP-2-null mice show an overall enhancement in wound healing. To assess potential compensation of one protein for the other, we examined cutaneous wound healing and fibrovascular invasion of subcutaneous sponges in SPARC-TSP-2 (ST) double-null and wild-type (WT) mice. Epidermal closure of cutaneous wounds was found to occur significantly faster in ST-double-null mice, compared with WT animals: histological analysis of dermal wound repair revealed significantly more mature phases of healing at 1, 4, 7, 10, and 14 days after wounding, and electron microscopy showed disrupted ECM at 14 days in these mice. ST-double-null dermal fibroblasts displayed accelerated migration, relative to WT fibroblasts, in a wounding assay in vitro, as well as enhanced contraction of native collagen gels. Zymography indicated that fibroblasts from ST-double-null mice also produced higher levels of matrix metalloproteinase (MMP)-2. These data are consistent with the increased fibrovascular invasion of subcutaneous sponge implants seen in the double-null mice. The generally accelerated wound healing of ST-double-null mice reflects that described for the single-null animals. Importantly, the absence of both proteins results in elevated MMP-2 levels. SPARC and TSP-2 therefore perform similar functions in the regulation of cutaneous wound healing, but fine-tuning with respect to ECM production and remodeling could account for the enhanced response seen in ST-double-null mice.

Animals↗
PubMed1975

Polyvinyl alcohol (Ivalon)--a new embolic material.

Successful nonsurgical treatment of gastrointestinal bleeding and arteriovenous malformations by embolization techniques has been previously documented. 1) Compressed Ivalon sponge was found to be a suitable embolic material in animals and in four patients. 2) The material has been extensively used in surgery, and its biocompatibility has been proved. 3) Expansion of the compressed sponge to its original size after embolization makes this material extremely effective. Recanalization did not occur in animals and humans. 4) For the occlusion of larger arteries, Ivalon can be wrapped around the guidewire. Ivalon sponge absorbs blood and serum, unwraps itself allowing withdrawal of the guidewire. 5) Embolization procedures are not without risk since reflux of embolic material may occur. Therefore, these procedures have to be carried out under fluoroscopic control.

Animals↗