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PubMed2003

In vitro study of the compatibility of tris-acryl gelatin microspheres with various chemotherapeutic agents.

PURPOSE: To evaluate the in-vitro effects of chemotherapeutic agents on the physical structure of tris-acryl gelatin microspheres. MATERIALS AND METHODS: Microspheres (Embospheres) were mixed in vitro with carboplatin, mitomycin C, 5-fluorouracil, or pirarubicin as experimental samples and with distilled water as control samples and kept for 24 hours at 37 degrees C. The microspheres used measured 100-300 micro m and 700-900 micro m in diameter. Microsphere morphology, including appearance, overall shape, smoothness of surface, and thickness of gelatin coating, was examined with use of a microscope equipped with a cold light. Microsphere dimensions including larger diameter, smaller diameter, and surface area were measured by granulometry. Microsphere geometry was evaluated by calculating a sphericity index and surface regularity index. Qualitative and quantitative variables, respectively, were analyzed with the two-sided Fisher exact test and Wilcoxon signed-rank test for paired values, with a significance level of 0.05. RESULTS: No broken microspheres or microscopic degradations in the appearance, overall shape, smoothness of surface, or thickness of gelatin coating of any microspheres were observed. The respective distributions of large and small diameters, surface area, sphericity index, or surface regularity index of the microspheres were not significantly different between the experimental samples containing carboplatin, mitomycin C, 5-fluorouracil, or pirarubicin and the control sample of microspheres with similar diameters. CONCLUSION: Embosphere microspheres can be mixed with carboplatin, mitomycin C, 5-fluorouracil, or pirarubicin for chemoembolization therapy without any risk of damaging their morphology, dimensions, or geometric characteristics.

Acrylates↗
PubMed2005

Partition of calibrated tris-acryl gelatin microspheres in the arterial vasculature of embolized nasopharyngeal angiofibromas and paragangliomas.

PURPOSE: To determine the location of calibrated tris-acryl gelatin microspheres (TGMs) in the arterial vasculature of nasopharyngeal angiofibromas (NAFs) and paragangliomas (PGs). MATERIALS AND METHODS: Forty-nine specimens (25 PGs and 24 NAFs) treated operatively after embolization with TGMs of various sizes (100-300 microm to 900-1200 microm) were stained with hematoxylin and eosin saffron and analyzed at an objective magnification of 10 or 20 with a micrometric eyepiece (magnification, x12.5). The diameter of occluded vessels, their localization (intra- or extratumoral), and the number and diameter of TGMs they contained were determined. RESULTS: Embolized vessels (N = 1125) were measured: 440 in PGs and 685 in NAFs. Vessels were 89% intratumoral and 11% extratumoral. The diameter of the occluded vessels increased significantly with the size range of TGMs used for embolization for each tumor type (P < .0001). Intratumoral occluded vessels were significantly smaller than extratumoral vessels (P < .0001). Distribution of TGMs within the vascular network (intratumoral or extratumoral location) were similar for NAFs and PGs. The intratumoral and extratumoral dissemination of TGMs was different when comparing 100-300-microm TGMs versus 500-700-microm TGMs (P = .0006) as well as 300-500-microm TGMs versus 500-700-microm TGMs (P = .0001). CONCLUSIONS: The size of the vessels occluded by TGMs and their intra- or extratumoral location directly depend on the size of the injected TGMs. The vessels located inside the tumors were smaller than those located outside the tumors. A threshold for the intratumoral penetration of TGMs in the vasculature can be proposed from these data. There was no evidence of different behavior of TGMs in NAFs versus PGs.

Acrylic Resins↗
PubMed2005

Spherical polyvinyl alcohol versus tris-acryl gelatin microspheres for uterine artery embolization for leiomyomas: results of a limited randomized comparative study.

PURPOSE: To compare the outcomes of uterine artery embolization (UAE) for leiomyomas with use of tris-acryl gelatin microspheres (TAGM) versus spherical polyvinyl alcohol (PVA) particles. MATERIALS AND METHODS: Patients undergoing UAE were randomly assigned to receive TAGMs or PVA. Embolization was performed in a standardized manner. Outcome data were collected at 3 months after embolization, including assessment of clinical symptoms, scores from a fibroid tumor-specific symptom and quality of life (QOL) questionnaire, and findings on contrast material-enhanced magnetic resonance (MR) imaging, including the degree of tumor infarction and volume reduction. Data were analyzed with use of t tests, the Mann-Whitney U test, and chi2 tests as appropriate. RESULTS: Thirty-six patients were treated. There were no differences in the two treatment groups at baseline. Clinical follow-up was obtained in 35 patients. Among the clinical outcome measures, QOL score improvement was greater for UAE with TAGMs compared with PVA (49.0 vs 27.9; P = .02), but no other differences were noted. Of the 25 patients in whom 3-month MR imaging follow-up was completed, those treated with TAGM were significantly more likely to have complete infarction of all leiomyomas (six patients vs one patient; P = .02), were more likely to have at least 90% tumor infarction (eight patients vs four patients; P = .03), and had a lower mean percent of residual perfused fibroid tumor tissue (9.6% vs 44.3%; P = .004) compared with patients treated with PVA. Based on these differences between the embolic agents, enrollment in this study was terminated. CONCLUSION: The use of spherical PVA particles in the manner described herein results in an unacceptably high rate of failed tumor infarction in UAE.

Acrylic Resins↗
PubMed2006

Effects of utero-ovarian anastomoses on basal follicle-stimulating hormone level change after uterine artery embolization with tris-acryl gelatin microspheres.

PURPOSE: To assess the prevalence of anastomoses between uterine and ovarian arteries on angiography and their impact on changes in basal follicle-stimulating hormone (FSH) level after uterine artery embolization (UAE). MATERIALS AND METHODS: Consecutive premenopausal women who underwent UAE for symptomatic uterine leiomyomata according to a uniform embolization technique with tris-acryl gelatin microspheres at a single institution were included in the study. Basal FSH levels before UAE and 6 months after UAE were compared for patients with and without anastomoses between uterine and ovarian arteries on angiography. RESULTS: Among 124 patients included in the study (mean age, 43.1+/-5.7 years), patent anastomoses between the uterine and ovarian arteries were detected by angiography in 55 patients (44.4%). Overall, 11.3% of 124 patients showed an increase in basal serum FSH level of greater than 20 mIU/mL after UAE. In patients with utero-ovarian anastomoses, 18.2% showed an increase of greater than 20 mIU/mL after UAE, compared with 5.8% of patients without such anastomoses (P=.03). Mean basal FSH increase after UAE in patients with anastomoses was 8.4+/-20.2 mIU/mL, compared with 2.7+/-10.6 mIU/mL in patients without anastomoses (P=.047). Among patients with anastomoses, the 50- to 54-year age group had the highest percentage of patients with an FSH increase greater than 20 mIU/mL (50.0%) after UAE, followed by patients in the 45- to 49-year age group (15.4%). CONCLUSIONS: Angiographically detected anastomoses between the uterine artery and the ovarian artery are not uncommon. UAE in patients with anastomoses is associated with a greater risk of significant increase of basal FSH level than in UAE in patients without anastomoses. The pathophysiologic processes resulting in change of FSH level may be a reflection of diminished ovarian function, but further study is warranted to delineate the precise mechanism.

Acrylic Resins↗
PubMed2002

The actuation of a biomimetic poly(vinyl alcohol)poly(acrylic acid) gel.

Active polymer gels expand and contract in response to certain environmental stimuli, such as the application of an electric field or a change in the pH level of the surroundings. This ability to achieve large, reversible deformations with no external mechanical loading has generated much interest in the use of these gels as biomimetic actuators and "artificial muscles". In previous work, a thermodynamically consistent finite-elastic constitutive model has been developed to describe the mechanical and actuation behaviours of active polymer gels. The mechanical properties were characterized by a free-energy function, and the model uses an evolving internal variable to describe the actuation state. In this work, an evolution law for the internal variable is determined from free actuation experiments on a poly(vinyl alcohol)poly(acrylic acid) (PVAPAA) gel. The complete finite-elastic/evolution law constitutive model is then used to predict the response of the PVA-PAA gel to isotonic and isometric loading and actuation. The model is shown to give relatively good agreement with experimental results.

Acrylic Resins↗
PubMed1985

Predictive value of assessment of lymph node weight and T-lymphocyte proliferation in contact sensitivity in acrylates.

An assessment of T-lymphocyte proliferation and lymph node weight is proposed as a predictive test for contact sensitizers of industrial origin. Data are presented showing increased T-lymphocyte proliferation following epicutaneous application of a variety of industrially important acrylate-like chemicals which appear to correlate well with their ability to sensitize in the guinea pig. These data were compared with those obtained after application of 2,4-dinitro-1-fluorobenzene (DNFB) a strong sensitizer, and 2,4-dinitrothiocyanatebenzene (DNTB) a nonsensitizer when given epicutaneously. It is suggested that this quantitative approach, in parallel with a simple one-dose immunization, may provide a better picture of sensitization potential than the longer multidose immunizations currently in use.

Acrylates↗
PubMed1977

Sarcoid granulomas of the skin produced by acrylic and nylon fibres.

The introduction into the skin of organic or inorganic substances can produce sarcoid-like granulomas. Two new granulomas of this type are described related to acrylic and nylon fibres. The aetiological diagnosis of such lesions can be confirmed by the identification of these synthetic materials within the-granuloma cells, using histochemical techniques used in the textile industry. An 'individual factor', probably immunological in nature, may be implicated.

Acrylic Resins↗
PubMed2004

Localized granulomatous reaction to a semi-permanent hyaluronic acid and acrylic hydrogel cosmetic filler.

Dermalive, an injectable skin filler composed of a combination of synthetic hyaluronic acid and acrylic hydrogel particles was recently developed for soft tissue augmentation. Dermalive produces longer term results than temporary injectable fillers and is associated with a reportedly low incidence of adverse reactions. We describe a marked local reaction to the injection of Dermalive in the nasolabial fold developing within 4 months with histological confirmation of a granulomatous response. To our knowledge there has been only one previous report of a local granulomatous reaction to Dermalive.

Acrylates↗
PubMed1990

Comparison of the dimensional stability of two waxes and two acrylic resin processing techniques in the production of complete dentures.

Two base plate waxes and two denture processing techniques were independently compared for dimensional stability. Occlusion rims were constructed from extra hard and medium soft base plate waxes and teeth were set. Acrylic resin bases were processed by a trial packing technique, and a continuous injection system. Tooth movement was measured in the horizontal and vertical planes to assess wax and denture base dimensional changes at various steps in the process, and after 1, 3, and 8 weeks of denture base immersion in water at room temperature. Posterior palatal border adaptation, incisal pin opening and loss of centric occlusion contacts, were also measured. Results showed there were no significant differences between the two waxes as determined by tooth movement in the horizontal and vertical planes. In comparison to the trial packing technique, the continuous injection system showed significantly smaller changes for incisal pin opening and loss of centric occlusion, and better adaptation of the posterior palatal border to the cast. Measurement of tooth movement in the horizontal and vertical planes showed no significant differences between the two processing techniques for times prior to immersion in water, whereas after 8 weeks immersion the continuous injection technique showed smaller dimensional changes, relative to the original dimensions at the time of investing.

Acrylic Resins↗
PubMed1995

Development and assessment of an objective method of colour change measurement for acrylic denture base resins.

Current standard specifications for the laboratory evaluation of denture base materials require subjective assessment of colour stability. This study evaluates a new objective measurement technique for translucent denture base materials, by comparing quantitative data with the results obtained from a standard subjective method. Preliminary work on three representative commercial acrylic materials resulted in the selection of a white background for the quantification of colour change of these translucent materials. One half of each sample was exposed to artificial sunlight for 24 h. The colour of both exposed and unexposed resin was measured on the CIE L*a*b* scale using a photo-electric colorimeter. Significant changes in the b* and E* values (P < 0.01) were observed following light exposure. Objective data for a wide range of commercial materials were compared with the results of a subjective evaluation and it was shown that a change in b* of 1.5 units was discernable subjectively by eye for 100% of the cases. It is suggested that this method and limit value could form the basis of a new objective colour change specification for polymeric dental materials.

Acrylic Resins↗
PubMed2004

An in vitro study into the effect of a limited range of denture cleaners on surface roughness and removal of Candida albicans from conventional heat-cured acrylic resin denture base material.

This study evaluated the abrasiveness of four denture cleaners on the surface of denture base material and assessed their ability to remove Candida albicans. Acrylic resin discs 20 mm diameter and 2 mm thick were identically produced and polished. Four cleaners were evaluated: conventional toothpaste; toothpaste with stain remover; denture cleaning paste and an immersion type cleaner, and water were used as control. These were used at dilutions of 1:1, 1:2 and 1:3 with water. An electric toothbrush was used, and the discs cleaned to simulate 1 years' cleaning. The surface roughness of the discs were then measured, before and after cleaning, using a stylus profilometer, then inoculated with 1.2 x 10(6)C. albicans cells. The effectiveness of the denture cleaners to remove C. albicans cells was assessed following a single cleaning event. The immersion cleaner was significantly less abrasive than paste cleaners (P < 0.05). There were no significant differences between any dilutions for any cleaner used (P > 0.05). Immersion and paste cleaners removed almost all recoverable C. albicans from the discs, as cleaning with water alone was less effective (P < 0.05). An immersion type cleaner was found to be the most suitable cleaner because of its low abrasivity and effective removal of organic debris.

Acrylic Resins↗
PubMed1991

Enzymatic peptide synthesis in organic solvent mediated by gels of copolymerized acrylic derivatives of alpha-chymotrypsin and polyoxyethylene.

Copolymers of acrylated derivatives of alpha-chymotrypsin and polyethylene glycol (PEG) have been prepared and used as biocatalysts for the synthesis of model peptides in organic solvent containing a low quantity of water. Other peptide couplings have been tried to point out the chemico- and stereoselectivity and examples of segment couplings are given.

Acrylates↗
PubMed2005

Detection of human neutrophil elastase with peptide-bound cross-linked ethoxylate acrylate resin analogs.

An assessment of elastase-substrate kinetics and adsorption at the solid-liquid interface of peptide-bound resin was made in an approach to the solid-phase detection of human neutrophil elastase (HNE), which is found in high concentration in chronic wound fluid. N-succinyl-alanine-alanine-proline-valine-p-nitroanilide (suc-Ala-Ala-Pro-Val-pNA), a chromogenic HNE substrate, was attached to glycine-cross-linked ethoxylate acrylate resins (Gly-CLEAR) by a carbodiimide reaction. To assess the enzyme-substrate reaction in a two-phase system, the kinetic profile of resin-bound peptide substrate hydrolysis by HNE was obtained. A glycine and di-glycine spacer was placed between the resin polymer and substrate to assess the steric and spatial requirements of resin to substrate with enzyme hydrolysis. The enzymatic activities of suc-Ala-Ala-Pro-Val-pNA and suc-Ala-Ala-Pro-Ala-pNA on the solid-phase resin were compared with similar analogs in solution. An increase in visible wavelength absorbance was observed with increasing amounts of substrate-resin and enzyme concentration. Enzyme hydrolysis of the resin-bound substrate was also demonstrated on a polypropylene surface, which was employed for visible absorbance of released chromophore. A soluble active substrate analog was released from the resin through saponification of the ethoxylate ester linkages in the resin polymer. The resin-released conjugate of the HNE substrate demonstrated an increased dose response with increasing enzyme concentration. The synthesis and assay of elastase substrates bound to CLEAR resin gives an understanding of substrate-elastase adsorption and activity at the resin's solid-liquid interface for HNE detection with a solid-phase peptide.

Acrylates↗
PubMed1995

Increased resistance of Escherichia coli to acrylic acid and to copper ions after cold-shock.

The effects of cold-shock on the resistance of plasmid-free and plasmid-carrying Escherichia coli to acrylate and copper ions have been tested. Such shock, produced by transfer from 37 to 5 degrees C, with 60 min incubation at the lower temperature, significantly enhanced the resistance of all the tested strains to both inhibitors. Such resistances may have arisen because the inhibitory agents are less able, due to porin changes, to penetrate into the organisms after cold-shock. It is more likely, however, that inhibitor penetration is unaffected but that cold-shocked organisms are better able to repair the damage caused (e.g. to membranes, DNA or cellular enzymes) by the inhibitors.

Acrylates↗
PubMed1993

Notch in contrast sensitivity function of optical origin: diffraction effects of acrylic filters.

A series of retinal image degrading filters was evaluated by measuring the contrast sensitivity function of four human subjects through the filters (residual CSF). The acrylic filters, with regularly spaced cross-hatches, produced progressively more reduction in the residual CSF as the density of the cross hatching increased. For some of the filters there was a selective loss of a narrow band of spatial frequencies as a result of diffraction effects. This experiment serves to further emphasize the need to rule out optical causes of such notches in the CSF before making a diagnosis of neurological dysfunction.

Acrylic Resins↗
PubMed1997

Fabrication of acrylic resin copings for CeraOne provisional restorations.

A technique is described for fabricating autopolymerizing acrylic resin copings for CeraOne provisional restorations. This method has the advantage of providing a chemical bond rather than only a bond between the mechanical coping and the relined provisional crown, as is the case when using the provisional components supplied by the manufacturer. The technique describes provisionalization at the time of stage II surgery. This type of coping can also be used after a period of soft tissue healing when a healing abutment is employed. The benefits of the procedure include increased patient satisfaction and reduced chair time for repairs.

Acrylic Resins↗
PubMed2004

Comparison of the dimensional accuracy of injection-molded denture base materials to that of conventional pressure-pack acrylic resin.

PURPOSE: This study compared the linear dimensional changes of 3 injection-molded denture base materials to that of conventionally processed polymethylmethacrylate (PMMA) resin. MATERIALS AND METHODS: An impression of an aluminum maxillary edentulous arch was made with a condensation silicone impression material (Denture Elasticon) to fabricate a gypsum master cast that was replicated as a silicone mold. A maxillary complete denture with acrylic teeth was waxed to full contour on the master cast and replicated to make 40 wax dentures. ERA attachments cast in metal (Rexillium) with indices milled into the centers were waxed into 3 positions in each denture for recording dimensional measurements of the wax denture. Ten dentures were allocated to each of 4 groups; Group 1 was processed using conventionally processed PMMA (Microlon), Group 2 used injection-molded PMMA (SR-lvocap), Group 3 employed injection-molded nylon (Valplast), and Group 4 used injection-molded styrene (Northern). All processed specimens were stored at room temperature (25 degrees C, ambient humidity) for 1 week (while still on the master cast) before anteroposterior and cross-arch measurements were made using the ERA reference points with a digital caliper. After separation from the master cast and following water storage at 37 degrees C for 7 days additional measurements were made. RESULTS: An analysis of the results showed that the effect of processing was not the same for the 3 dimensions studied, regardless of which dimension was considered (p < 0.0001). The pattern of dimensional changes associated with the material type was not the same between the wax and processing stages as it was for the change between the processing and decasting stages (p < 0.0001). CONCLUSIONS: Processing the denture base materials produced unequal deformation in different dimensions (anterior-posterior and cross-arch). Each material tested also responded differently to the processing stages.

Acrylic Resins↗
PubMed2005

Using silicone impression material and acrylic resin to fabricate remount casts for removable partial dentures.

A technique is described for fabrication of a remount cast for a removable partial denture. This procedure consists of filling the occlusal/incisal third with acrylic resin and injecting polyvinylsiloxane impression material into the irreversible hydrocolloid impression. This technique provides a simple method for making a remount cast and enables the clinician to remove and easily place the partial denture on the cast during occlusal refinement procedures without damage to the removable partial denture or the remount cast.

Acrylic Resins↗