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At least 649 records · Page 36Linked to original sources
PubMed1997

Acrylic cranioplasty with alginate molding: technical note.

OBJECTIVE: Acrylic cranioplasty for cranial defects is a common neurosurgical procedure that is performed when the original bone flap becomes infected or is unusable for other reasons. We developed a simple technique to produce a complete copy of the original bone flap from acrylic, using alginate impression material as a mold. METHODS: Alginate impression material was used to form a mold of the patient's original bone flap. Methylmethacrylate was then placed inside the mold to create an exact duplicate of the bone flap. The acrylic flap was sterilized with gamma irradiation and used for cranioplasty. Two patients who had cranial defects secondary to infections of their craniotomy bone flaps underwent cranioplasty with this technique. RESULTS AND CONCLUSION: A perfect copy of the patient's original bone flap was easily and quickly created with this technique, and excellent cosmetic results were obtained. Operative time was shortened because the prosthesis was preformed before the operation. This technique can also be used to mold large or complex cranial defects as long as the original bone flap is available and there is no major cranial remodeling around the defect.

Alginates↗
PubMed2006

Addition of fluoride to acrylic bone cement does not improve fixation of a total hip arthroplasty stem.

UNLABELLED: Improved fixation to bone is vital for improving the long term success of cemented implants. Addition of fluoride to acrylic bone cement may be one way to improve the quality of the bone cement interface and thereby reduce the risk of loosening. Ninety patients (97 hips) with a median age of 70 years (range, 31-81 years) scheduled for total hip arthroplasty were randomized to receive a stem fixed with fluoride-containing acrylic bone cement or conventional acrylic bone cement. Fixation and bone remodeling around the femoral component was studied with radiostereometry and dual-energy xray absorptiometry up to 5 years after the operation in 73 patients (77 hips). Radiostereometric evaluation at 5 years revealed no differences in stem migration (subsidence/lift-off) or rotations. The stem subsidence inside the mantle was similar in the two groups. At 5 years the study group had lost more bone mineral in Gruen regions 5 and 7 than the controls. The Harris hip and pain score did not differ. Use of fluoride containing bone cement did not improve the stem fixation compared with a conventional cement used up to 5 years, but resulted in more pronounced loss of bone mineral density in the medial cortex. LEVEL OF EVIDENCE: Therapeutic Level I. See Guidelines for Authors for a complete description of levels of evidence.

Adult↗
PubMed2003

Foot dermatitis caused by the textile dye Basic Red 46 in acrylic blend socks.

17 male subjects are described with foot dermatitis in association with positive patch test reactions to the textile dye Basic Red 46. Chromatographic analysis of the socks of 2 affected patients confirmed the presence of Basic Red 46. Withdrawal of the acrylic blend socks suspected of having been dyed with Basic Red 46 resulted in the improvement of symptoms in 12 of 17 patients (70.6%). However, equivocal or negative patch test results to their own socks were frequently noted in those patients. A highly significant association between the presence of foot dermatitis and a positive Basic Red 46 patch test reaction was noted in 555 patients from a patch test clinic population (P < 0.001). The prevalence of positive patch test reactions to Basic Red 46 was 1.2%. We suggest that patients with foot dermatitis be routinely patch tested for textile dyes. In particular, testing with Basic Red 46 should be considered in those with a history of use of dark-coloured acrylic and/or acrylic blend socks.

Adult↗
PubMed1997

Cracked acrylic intraocular lens requiring explantation.

BACKGROUND: Intraoperative cracking of foldable acrylic posterior chamber intraocular lenses has previously been documented. However, most cracks have resulted in no significant visual impairment. METHODS: A case report of an acrylic posterior chamber intraocular lens that cracked during folding. RESULTS: The crack in the lens resulted in significant optical disturbance and required explanation and insertion of another lens. CONCLUSIONS: Acrylic intraocular lenses must be folded carefully with appropriate forceps to prevent cracking of the optic.

Cataract Extraction↗
PubMedDate not supplied

Thermodynamic considerations of acrylic cement implant at the site of giant cell tumors of the bone.

A discussion of the thermodynamic aspects of a relatively new treatment method for giant cell tumors of the bone is presented in this paper. The advantages of implanting methylmethacrylate acrylic bone cement into a curetted tumor site are briefly discussed and placed in perspective relative to more prevalent surgical treatments. As the bone cement self-heats while curing, the possibility of heat necrosis in the bone exists. However, the damage due to heat may be beneficial in reducing the rate of tumor recurrence. A thermodynamic consideration of the treatment situation appears to be warranted. After a general introduction and a brief literature review, the theoretical thermodynamic equations are developed. Once the basic equations for the heat transfer from the cement or the bone are derived, there is then a discussion of the various characteristics of bone and methylmethacrylate crucial to the analysis, such as, thermal conductivity, specific heat, density, and heat generation parameters. Finally, in order to reduce the theory to a form which may be used practically, the equations derived are written in terms of finite-difference equations, which approximate them numerically. Different equations are written for each type of heat transfer condition encountered in the cement-bone system as spacial variances in material and geometry occur. The equations derived may be used to model the system allowing one to predict the time-dependent temperature distribution in bone during the curing of acrylic cement. Using computer techniques to reduce the equations obtained from this analysis, and knowing the temperature at which adjacent cells die, a zone of necrosis may be mapped surrounding the acrylic impact.

Bone Neoplasms↗
PubMed2006

Preparation, formulation and evaluation of novel photo-cured glass ionomers based on co-polymers of (meth)acrylated amino acids.

A novel photo-cured amino-acid-constructed glass-ionomer cement system has been developed. Glutamic acid- and beta-alanine-based methacrylate and acrylate derivatives were synthesized, characterized and used to construct the polyalkenoic acids and formulated with water and Fuji II glass filler to form self-cured cement. Compressive strength (CS) of the cement and viscosity of the liquid were used as tools for evaluation. The effects of molar ratio and molecular weight (MW) were studied. The optimized co-polymer was further modified with glycidyl methacrylate (GM) and formulated with water, acrylic acid and Fuji II LC filler to form photo-cured cement. The effects of MW, GM tethering ratio, polymer liquid ratio and glass filler powder/polymer liquid (P/L) ratio were investigated. CS, flexural strength (FS) and viscosity were used as screening tools to find the optimal formulation. All the specimens were conditioned in distilled water at 37 degrees C for either 24 h or 7 days prior to testing. The results show that amino-acid-constructed polyalkenoic acids can be formed only from amino acid methacrylate derivatives or by co-polymerization of methacrylate with acrylate derivatives. Among the numerous co-polymers synthesized, poly(methacryloyl glutamic acid-co-acryloyl beta-alanine) or poly(MGA-co-ABA) with the molar ratio of 8:2 and MW of 19.5 kg/mol contributed the highest mechanical strengths and lower working viscosity to the cement. For photo-cured system, the effects of GM tethering ratio, polymer content and P/L ratio were significant. It is found that an appropriate ratio balance between these parameters is very important. The effect of molecular weight was not significant. The self-cured experimental cement was 32% higher in FS than Fuji II and the same in CS and DTS as Fuji II. The photo-cured experimental cement was 19%, 47% and 176% higher in CS, DTS and FS than Fuji II LC.

Amino Acids↗
PubMed2003

Fracture characteristics of acrylic bone cement-bone composites.

In this study, the fracture properties of Perspex, acrylic bone cement prepared using a commercially available reduced pressure mixing system and a bone cement-bone composite were compared under different test conditions. The method used was the double-torsion (DT) test. The observations made from this investigation are as follows. The fracture toughness and critical crack length for Perspex significantly increased (ANOVA, p = 0.001) when tested in water compared to air. An increase in test temperature from 19 to 37 degrees C resulted in a decrease in the fracture properties in water, this reduction being also statistically significant (ANOVA, p = 0.02). The mean fracture toughness and standard deviation of CMW3 bone cement when mixed under reduced pressure was 2.19 +/- 0.11 MN m(-3/2) compared to 3.89 +/- 0.10 MN m(-3/2) for the cement-bone composite (ANOVA, p = 0.004). The crack length determined for CMW3 bone cement and the cement bone composite were 0.323 +/- 0.031 and 1.1434 +/- 0.61 mm respectively. The plateau loads of the composite material were higher than measured for the monolithic acrylic bone cement, 249.66 +/- 67.75 N compared with 140.83 +/- 6.82 N. The high level of variation recorded for the plateau loads of the bone cement bone composite is due to the orientation and volume fraction of the cancellous bone. It can be concluded from this investigation that acrylic bone cement interdigitation into the cancellous bone results in a superior material with respect to crack resistance in comparison with the bone cement as a lone entity. Therefore it is an advantage if there is sufficient cancellous bone stock available within the intermedullary canal to allow bone cement penetration to occur, for the transfer of loads during daily activity. Additionally, it is paramount that the clinician ensures that adequate pressure is applied and maintained for an appropriate time during cement injection and prosthesis insertion in order to ensure optimum cement penetration into the pore openings of the cancellous bone, thus improving the resistance of the cement mantle to fracture and ultimately improving the longevity of the joint replacement.

Animals↗
PubMed2004

Propagation of fatigue cracks in acrylic bone cements containing different radiopaque agents.

In this work three iodine-containing monomers were proposed as new radiopaque agents for acrylic bone cements. In previous studies the addition of iodine-containing methacrylate monomers provided a statistically significant increase in tensile stress, fracture toughness and ductility, with respect to the barium sulphate (BaSO4)-containing cement. However, since fatigue resistance is one of the main properties required to ensure a good long-term performance of permanent prostheses, it is important to compare the fatigue properties of these new bone cement formulations with the radiolucent and BaSO4-containing bone cements. Because the acrylic cements have initial cracks, fatigue crack propagation studies were performed. It can be observed that these acrylic cements followed the Paris-Erdogan model. The results showed that the addition of some organic radiopacifiers (DISMA, TIBMA) increased the fatigue crack propagation resistance as compared to the radiolucent cement, being similar to the BaSO4-containing cement. The radiolucent cement showed a low crack propagation resistance.

Complex Mixtures↗
PubMed1990

In vitro release of doxycycline from bioabsorbable materials and acrylic strips.

Treatment of marginal periodontitis may include use of local antibiotics. In the present in vitro study the bioabsorbable materials Surgicel, Tissell, and CollaCote and acrylic strips were examined for release of doxycycline into liquids and residual antibacterial activity of the materials. Pieces of material were incubated in 1 ml of water or human serum which was exchanged every day for 9 days. The concentration of doxycycline in the liquids was measured spectrophotometrically while the residual antibacterial activity of the materials was determined microbiologically. Surgicel constantly showed very high concentrations and level of residual activity. The acrylic strip and CollaCote decreased to low levels of both concentration and residual activity in a few days. Tissell was intermediate with a continuous decrease in concentration but rather high level of residual activity throughout the study. In serum the acrylic strip was partly dissolved and Surgicel was totally dissolved after 2 days. Left undisturbed in serum Surgicel was not dissolved for 2 weeks. These results indicate that Surgicel and Tissel may be capable of prolonged release of doxycycline in vivo.

Actinobacillus↗
PubMed1990

Decreased blood perfusion in canine tibial diaphysis after filling with acrylic bone cement compared with inert bone wax.

Sixteen dogs had one tibia filled with acrylic PMMA bone cement and the opposite, control tibia filled with inert bone wax. After 1, 4, and 12 weeks, the blood perfusion in diaphyses was measured with Sc-46 labeled microspheres. The blood flow rates increased from 1 to 4 weeks and dropped to about the 1-week level after 12 weeks on both sides, with the acrylic side lower than the control side. On both sides, Disulphine Blue staining of the bones showed severe endosteal avascularity after 1 and 4 weeks and massive periosteal apposition after 4 and 12 weeks. The initial increase in blood flow is considered due to periosteal apposition, and the differences in blood flow rates are attributed to avascularity caused by the polymerization heat and toxicity of the acrylic cement.

Animals↗
PubMed2000

Incidence of nd:Yag capsulotomy after lens implantation of an Acrylic IOL in one eye and a Silicone IOL in the other eye of the same patient: a preliminary study.

We retrospectively reviewed the charts of 40 patients who underwent an uneventful phacoemulsification in both eyes and had an Acrylic IOL (AcrySof) implanted in one eye and a Silicone IOL (SI 30/S 140) in the other. A subset of 18 patients had a mean follow up of 1 1/2 year. In the Acrylic group 1 patient (5.5%) underwent a posterior Yag-capsulotomy. In the Silicone group 6 patients (30%) underwent a Yag-capsulotomy. (2 anterior--4 posterior) (p = 0.04) Acrylic IOL's were associated with a significantly reduced incidence rate of Yag-capsulotomy compared with silicone IOL's after 1 1/2 years.

Biocompatible Materials↗
PubMed2003

Acrylic cement added with antiblastics in the treatment of bone metastases. Ultrastructural and in vitro analysis.

An increased long-term survival of patients with alignant tumours also increases the possibility of the development of skeletal metastases and pathological fractures. The management of bone metastases includes the removal of gross disease and the administration of local adjuvants. We have investigated the possibility of adding antiblastic drugs to acrylic cement. Cylinders of acrylic cement were manufactured containing three different antiblastic drugs, methotrexate, cisplatin and doxorubicin. We performed in vitro analysis on MCF-7 human breast cancer cells in order to evaluate the biological effect of the mixtures and surface analysis of the acrylic cement-cisplatin cylinders using energy-dispersive x-ray analysis (EDAX). All drugs were released in an active form from the cement. Each drug had a different effect on cell viability. Doxorubicin had the greatest effect on breast cancer cells. Surface analysis showed that antiblastic drugs were present in the form of granules. These results confirm the potential of antiblastic-loaded cement as a possible adjuvant in the local treatment of bone metastases. Further studies should be undertaken to determine whether the release of antiblastic drugs from cement is elution or if they are only released from the surface.

Antineoplastic Agents↗
PubMed1992

Acrylic fragmentation in total hip replacements and its biological consequences.

Loosening of total joint prostheses is in part related to the fragmentation of the acrylic cement mantle surrounding the prosthesis and the biologic consequences to the particulate acrylic. Fractographic studies of femoral cement mantles retrieved at revision surgery and autopsy showed frequent fractures in varying stages of development in the cement and wear at the fracture surfaces. Defects in the cement mantle, thin mantles, sharp corners on the prosthesis, separation at the cement mantle interface, and pores in the cement were frequently associated with cement fractures. The progressive fractures and wear led to the liberation of particulate acrylic debris into the surrounding tissues. The tissues at the bone-cement interface removed at revision surgery showed that a macrophage, giant-cell foreign-body granulomatous reaction occurs in response to the particulate, but not bulk cement. This tissue can produce a variety of chemical mediators of inflammation and bone resorption, and can resorb bone in organ cultures. A granulomatous tissue reaction with a very similar appearance can be produced in experimental animals using particulate-form polymethylmethacrylate (PMMA), but not the bulk form of PMMA. The tissue reaction is not mediated by the classic cell or humeral immune mechanisms. Subcutaneous injection of particulate PMMA powder into fully immunocompetent C3Hf/SED mice as well as three strains of mice with progressive immunologic deficiencies (nude/nude, SCID, and triple deficient Nu-bg-XID/SED mice) led to a foreign-body reaction in all strains at five weeks as shown by histologic and immunohistochemical examination despite the differences in immune deficiency. This, along with the scarcity of lymphocytes in the human tissues, suggests that the biologic reactions to fragmented cement can be produced and sustained by nonimmune phagocytosis and activation by macrophages and giant cells without significant contribution by the immune system.

Aged↗
PubMedDate not supplied

Liquid chromatographic determination and identification of morantel-related residues as precursors of 3-(3-methyl-2-thienyl) acrylic acid (CP-20,107) in bovine milk.

A simple liquid chromatographic (LC) method was developed to determine and identify incurred morantel-related residues in bovine milk by converting them to 3-(3-methyl-2-thienyl) acrylic acid (CP-20, 107). Key techniques in this method involve short-term digestion of milk in HCl to release residues convertible to CP-20, 107, isolation and alkaline hydrolysis of these precursors to CP-20, 107, and recovery of the product for LC analysis. Photochemical conversion of CP-20, 107 to its cis-isomer and separation by LC identifies the residue. A homolog (pyrantel), which is used as an internal standard, is hydrolyzed to 3-(2-thienyl) acrylic acid. These acrylic acid isomers are readily resolved by LC. The method was evaluated over the 1-4 ppb (ng/mL) range for accuracy and precision to assess its utility for withdrawal studies. Bovine milk supplemented with morantel at 1, 2, and 4 ppb and assayed in replicate (n = 7-8) over 4 trials gave mean values and standard deviations of 1.0 +/- 0.11, 2.0 +/- 0.24, and 4.0 +/- 0.44 ppb, respectively. A milk specimen containing physiologically incurred residues of morantel assayed 2.1 +/- 0.19 ppb in replicate (n = 5).

Animals↗
PubMed1995

Occlusion of cerebral arteriovenous malformations with N-butyl cyano-acrylate is permanent.

PURPOSE: To verify the permanence of total occlusion of cerebral arteriovenous malformations after embolization with N-butyl cyano-acrylate and to evaluate the occlusion rate. METHODS: One hundred thirty-four patients were treated for cerebral arteriovenous malformations with N-butyl cyano-acrylate embolization after superselective catheterization. Those initially totally occluded have been followed with angiography. RESULTS: In 15 instances (11.2%) the arteriovenous malformations were totally occluded by embolization alone. Follow-up angiograms have been performed in 12 cases (80%) after 4 to 78 (mean, 27) months after embolization. In all instances the arteriovenous malformations have remained occluded, and there have been no clinical signs of activity. CONCLUSION: After total occlusion of a cerebral arteriovenous malformation with N-butyl cyano-acrylate, the lesion stays occluded, and the clinical course seems stable.

Cerebral Angiography↗
PubMed1995

Symptomatic pulmonary complications from liquid acrylate embolization of brain arteriovenous malformations.

PURPOSE: To describe symptomatic pulmonary emboli from brain arteriovenous malformation embolization with liquid acrylates and to analyze the reasons for these complications and describe preventive techniques. METHODS: The clinical records of 182 patients embolized with acrylate glue since 1978 for treatment of brain AVMs were searched for evidence of symptomatic pulmonary complications. Originally iso-butyl-2-cyanoacrylate and more recently n-butyl-2-cyanoacrylate were used in all patients. Arteriovenous malformation morphology, amounts and techniques of glue injection, and clinical and radiologic investigations in the symptomatic patients were recorded. RESULTS: Three patients had pulmonary symptoms within 48 hours of glue injection. One patient with a left frontal arteriovenous malformation had embolization with an isobutyl-2-cyanoacrylate/pantopaque/acetic acid mixture; severe pleuritic chest pain developed 2 days later. One patient with a left temporal and one with a left cerebellar arteriovenous malformation had embolization with n-butyl-2-cyanoacrylate/lipiodol mixtures; a cough, pleuritic chest pain, and bloody sputum developed in both within 24 hours. Two patients experienced a significant drop in PO2. No flow-arrest techniques were used for any of the injections in these three patients. All patients demonstrated significant changes on chest x-ray and CT chest examinations. All were treated conservatively and recovered spontaneously. CONCLUSIONS: Symptomatic pulmonary complications can occur after acrylate glue injection, particularly when delivery systems without flow arrest are used in high-flow vascular brain lesions. Techniques using acetic acid to delay polymerization time and "sandwich" techniques in which glue is pushed with dextrose are also more susceptible to this complication.

Acetates↗
PubMed1997

Human NAD(P)H:quinone oxidoreductase induction in human hepatoma cells after exposure to industrial acrylates, phenolics, and metals.

Induction of the endogenous human NAD(P)H:quinone oxidoreductase (HQOR1) gene in the human hepatoma cell line HepG2 was measured at both the enzyme activity and RNA levels after exposure to a variety of industrial compounds. An RNA probe was designed that was complementary to portions of both the coding region and the 3'-nontranslated region unique to the largest (2.7-kilobase) HQOR1 transcript. Induction by three strong inducers of HQOR1 verified the utility of the antisense RNA probe. Ten industrial chemicals were evaluated as potential inducers, i.e. acrylonitrile, Sb2O3, BaO, CdCl2, CuCl, ethyl acrylate, methyl acrylate, MoO3, phenol, and toluene. Induction at the RNA level was about 2-fold higher than at the enzyme activity level except in the case of acrylonitrile, for which induction at the enzyme activity and RNA levels was similar. There was no preferential induction of the 2.7-kilobase transcript for any chemical tested, including 2,3,7,8-tetrachloro-dibenzo-p-dioxin, which had previously been reported to preferentially induce this transcript. Six of the 10 industrial chemicals, including four previously untested chemicals (phenol, Sb2O3, CuCl, and MoO3), were found to induce the HQOR1 gene. By comparison, previous studies in rodent systems failed to accurately predict the human HQOR1 gene response. Two chemicals previously shown to be inducers in rodent systems (methyl acrylate and CdCl2 failed to induce the HQOR1 gene. These results emphasize the importance of analyzing induction of the endogenous human gene, rather than simply extrapolating from rodent systems or gene fusion experiments.

Acrylonitrile↗
PubMedDate not supplied

Penetration and flow of acrylic bone cement.

Fixation of prosthetic joint components into bone is influenced by the degree of mechanical interdigitation of the acrylic into cancellous interstices. The rheology of polymerizing polymethylmethacrylate was studied by pressurizing acrylic bone cement with a piston apparatus to produce flow into cylindrical cavities one to 3 mm in diameter. The acrylic penetration per unit of applied pressure increased with increasing cavity diameter. This suggests that greater penetration should occur in cancellous bone containing larger interstitial cavities. More than one-half (64 %) of the filling observed in our experiments took place within the first second of pressure application. Short duration, high level pressure pulses are the most effective means to achieve maximum penetration. Clinically, this is accomplished by vigorous finger packing. The cement should be pressurized as early as possible within the rasped cavity (immediately after dough stage if possible). The depth of penetration for 4-minute pressurization averaged three times that for 6 1/2-minute pressurization for the range of hole sizes and pressure levels tested.

Bone Cements↗