[Interaction of methylmethacrylate and acrylamide with the microsomal oxidation system of the rat liver]

A complex, exhibiting the maximal absorption at 385-388 nm and minimal at 414-420 nm, was formed after interaction between cytochrome P-450 and methylmethacrylate and acrylamide at 5 mM concentration. Acrylamide at concentrations higher than 6 mM induced the formation of modified type 11 differential spectra with maxima at 418 nm and minima at 385 nm. Methylmethacrylate and acrylamide stimulated utilization of NADPH and inhibited hydroxylation of 3,4-benzpyrene. Methylmethacrylate inhibited also N-demethylation of aminopyrine. After treatment of rats with the monomers activities of cytochromes P-450, b5 and NADPH-cytochrome c reductase were unaltered. Methylmethacrylate and acrylamide appear to interact with the microsomal oxidative system.

Distribution and elimination of polymethyl methacrylate nanoparticles after peroral administration to rats

Polymethyl [1-14C]methacrylate nanoparticles were administered orally to bile cannulated rats. Ten to fifteen percent of the administered radioactivity was absorbed and found in the bile and urine. Within 48 h, 94-97% of the absorbed radioactivity had been eliminated from the body. After 8 d, the highest residual radioactivity was found in the bone marrow, fatty renal tissue, stomach, liver, and lymph nodes.

Pharmacokinetic study of gentamicin-loaded cement in total hip replacements. Comparative effects of varying dosage

A randomised, double-blind study was performed in two groups of 15 patients undergoing total hip replacements, using antibiotic-loaded acrylic cement containing 0.5 g and 1.0 g gentamicin base respectively per 40 g pack of powdered polymer. Postoperatively, the gentamicin levels in the blood, in the urine and in the wound drainage fluid were measured. In both groups of patients, the serum gentamicin concentrations were low whereas the wound drainage fluid contained highly effective antibacterial concentrations. Serum, urine and wound secretion levels showed approximately two-fold higher concentrations in the group of patients receiving the higher gentamicin load.

Intravenous methylmethacrylate after total hip replacement

In eight patients, radiographs made after total hip replacement revealed methylmethacrylate in the soft tissues of the thigh. In one of them the configuration of the density was that of a vein. In the other seven patients similar but less extensive soft-tissue densities were seen postoperatively. One patient had postoperative hypotension which was thought to be due to a myocardial infarction. In another patient, with a prior history of congestive heart failure, congestive heart failure developed again after total hip replacement. The relationship of these complications to the radiographic observations was not clear.

Distribution and elimination of poly(methyl methacrylate) nanoparticles after subcutaneous administration to rats

Poly(methyl [1-14C]methacrylate) nanoparticles were injected subcutaneously into rats. Almost all of the radioactivity stayed at the injection site. After an initial urinary and fecal excretion of approximately 1% of the administered dose per day, the rate of elimination dropped to a low level (approximately 0.005%/day via the feces and approximately 0.0005%/day via the urine) within 70 days. After 200 days, the fecal elimination increased exponentially until a greater than 100-fold increase was observed after 287 days in one rat. After this time, a tendency for an increase in fecal elimination was also observed in the other animals, and the radioactivity in all organs and tissue increased by approximately 100 times in all animals in comparison with the organ radioactivity determinations at earlier times.

Incorporation of bone graft covered with methylmethacrylate onto acetabular wall. An experimental study

The acetabular model, as described in the present study, appears to serve as a promising experimental model for grafting procedures since it promotes the acceptance of autogenous grafts and the induction of new bone formation. Further, the biologic and mechanical properties of the femoro-acetabular joint appear permissive to the development of an efficient reparative system even when a foreign material such as methylmethacrylate cement is incorporated into the overall reconstructive procedure. Hence, it is hereby recommended to utilize the biological approach in the frame of replacement arthroplasty of severely damaged acetabulum.

Metabolism of methyl methacrylate: evidence for metabolism by the valine pathway of catabolism in rat and in man

1. Evidence to support the suggestion that methyl methacrylate is metabolized by the normal pathway of valine catabolism has been obtained by the administration of methyl [Me-14C]methacrylate to rats. 2. Of the administered dose, 80% was respired as 14CO2 as predicted, and methylmalonic acid, specifically labelled with 14C in a manner consistent with the proposed pathway of metabolism, was excreted (0.22%) dose). 3. Following administration of sodium [Me-2H3]methacrylate to a human subject, [Me-2H3]methylmalonic acid was detected in the urine by g.l.c.-mass spectrometry.

[Release and diffusion of methylmethacrylic monomers after the implantation of self curing bone cements. Study on laboratory specimens and animal experiments (author's transl)]

In this study the degree and the time interval of the release of toxic methylmethacrylic monomers in neighboring bone tissue has been investigated after implantation of self couring acrylic cements. It has been shown that the majority of unpolymerized monomers is diminuated by a biologically uneffective later polymerization; thus only a minor part of methylmethacrylic monomers undergoes diffusion. The processes occur mainly during the first 24 hrs after implantation and are below the laboratory detection after 2 weeks. Cement additives such as X-ray contrast materials (BaSO4 or ZrO2) do not influence these reactions. Among the cements investigated herein (CMW-bone cement, Surgical simplex, Palacos) pronounced differences in the release of residual monomers during the first week have clearly been demonstrated.

Treatment of bone and soft-tissue infections with gentamicin-polymethyl-methacrylate chains. A review of clinical trials involving 1 500 cases

In vitro and in vivo experimental work showed that gentamicin-polymethyl-methacrylate (G-PMMA) provides bactericidal gentamicin concentrations at the site of infection but very low systemic concentrations, suggesting advantages as regards infection control and lack of side-effects. During the past 4 years 1247 osteomyelitis patients have been treated with G-PMMA at 11 clinics. The early postoperative results showed control of infection in 90.8% of cases. Infection persisted in 9.2% owing to remaining sequestra, osteosynthetic material, etc. This indicates the importance of good and radical surgery. Follow-up of 355 patients for 3 - 54 months postoperatively showed relapses in only 27 cases. A total of 361 patients with soft-tissue infections (e.g. associated with bone infections, sacral cavity after rectum excision, abscesses, etc.) underwent treatment with G-PMMA after thorough debridement, with good results. Techniques for implantation, and removal of the chains are discussed. No adverse effects have been observed in this series of trials.

[The excretion of methylmethacrylate from bone cement through the lungs (author's transl)]

By using a continuous infra-red monitoring technique, it could be shown that in 42 patients undergoing TEP surgery methylmethacrylate is excreted through the lungs. The amount of monomer eliminated in the exhaled air is less following acetabulum implantation than following femoral shaft implantation. The concentration of monomer in the exhaled air is strongly influenced by measures such as femoral shaft drainage, washing the implantation site with icewater and lengthening the cement mixing time which reduce the transfer of the monomer. Pulmonary elimination of MMA-monomer takes 20 min and is very fast.

Biodegradation of polystyrene, poly(metnyl methacrylate), and phenol formaldehyde

The biodegradation of three synthetic 14C-labeled polymers, poly(methyl methacrylate), phenol formaldehyde, and polystyrene, was studied with 17 species of fungi in axenic cultures, five groups of soil invertebrates, and a variety of mixed microbial communities including sludges, soils, manures, garbages, and decaying plastics. Extremely low decomposition rates were found. The addition of cellulose and mineral failed to increase decomposition rates significantly.

In vitro studies of poly(methyl methacrylate) adjuvants

Poly(methyl methacrylate) adjuvants, prepared by polymerizing monomeric methyl methacrylate in the presence of influenza virions or by addition of the virions to previously polymerized poly(methyl methacrylate) particles, were studied by means of the hemagglutination test, antibody binding, and electron microscopy. The results indicated that the virions were coated partly when the polymerization was carried out in the presence of the virus, whereas the virions were probably adsorbed when added to polymerized particles.

Toxicology of methyl methacrylate: the rate of disappearance of methyl methacrylate in human blood in vitro

1. The rate of disappearance of methyl methacrylate in blood has been determined using an isotope dilution technique. 2. At a concentration of 10(-4) mol dm(-3), methyl methacrylate disappears with pseudo first order kinetics. 3. The half-life of methyl methacrylate in blood at 37 degrees C lies in the range 20--40 min. 4. The half-life showed no dependence on the age or sex of the blood donor. 5. A major, possibly the only, pathway of metabolism is by hydrolysis to methacrylic acid.

Cultivation of periodontal ligament fibroblasts on dental implant materials and enzymatically debrided teeth

Rhesus monkey periodontal ligament-derived fibroblasts were cultured on glass, Vitallium, poly(methyl methacrylate) and enzymatically debrided teeth. Scanning electron micrographs of these preparations and of the periodontal ligament surrounding normal and replanted teeth were compared. The fibroblasts cultured in vitro could organize on implant material and enzymatically debrided teeth to produce a network with fibers resembling those that are seen in the normal periodontal ligament.

Organic polymeric polyphosphonates as potential preventive agents of dental caries: in vitro experiments

Organic polymeric polyphosphonates adsorb on enamel surfaces in the form of a monolayer and inhibit calcium and fluoride ion transport but not that of phosphate ions. The polymers investigated include phosphonated polyethylene, polyvinylphosphonate, and polyvinylbenzylphosphonate. The adsorption of proteins on enamel, as exemplified by human serum albumin, is diminished and the adsorbed protein is more readily desorbed from surfaces with polymeric polyphosphonates. These jendings may offer an explanation for the anticariogenic effect of polymeric polyphosphonates.