Exposure of medical personnel to methylmethacrylate vapor during percutaneous vertebroplasty.
The occupational exposure to methylmethacrylate (MMA) vapor during percutaneous vertebroplasty was determined. During five vertebroplasty procedures, air-sampling pumps were attached to medical personnel. MMA vapor levels in the samples were then quantified using gas chromatography. The samples collected yielded MMA vapor levels of less than five parts per million (ppm). The MMA vapor concentrations measured were well below the recommended maximum exposure of 100 ppm over the course of an 8-hour workday. (+info)
Pulmonary embolism caused by acrylic cement: a rare complication of percutaneous vertebroplasty.
A pulmonary embolus of acrylic cement was present in a 41-year-old woman with Langerhans' cell vertebral histiocytosis (LCH) after percutaneous vertebroplasty. Chest radiograph and CT confirmed pulmonary infarction and the presence of cement in the pulmonary arteries. She was treated with anticoagulants, and responded favorably. This rare complication occurred because perivertebral venous migration was not recognized during vertebroplasty. Adequate preparation of cement and biplane fluoroscopy are recommended for vertebroplasty. (+info)
Actin motion on microlithographically functionalized myosin surfaces and tracks.
High-resolution e-beam patterning exposure of the surface of poly[(tert-butyl-methacrylate)-co-(methyl methacrylate)]-a common e-beam and deep-UV resist used in semiconductor microlithography-induced sharp changes in the surface hydrophobicity. These differences in hydrophobicity resulted in the selective attachment of heavy meromyosin to hydrophobic, unexposed surfaces. The movement of the actin filaments on myosin-rich and myosin-poor surfaces was statistically characterized in terms of velocity, acceleration, and angle of movement. The actin filaments have a smooth motion on myosin-rich surfaces and an uneven motion on myosin-poor surfaces. Interestingly, an excess of myosin sites has a slowing, albeit mild effect on the motion of the actin filaments. It was also found that the myosin-rich/myosin-poor boundary has an alignment-enforcement effect, especially for the filaments approaching the border from the myosin-rich side. Based on these results, we discuss the feasibility of building purposefully designed molecular motor arrays and the testing of the hypotheses regarding the functioning of the molecular motors. (+info)
Cell and protein adhesion studies in glaucoma drainage device development. The AGFID project team.
AIM: To examine in vitro whether phosphorylcholine coating of poly(methylmethacrylate) can reduce the adhesion of fibrinogen, fibrin, human scleral fibroblast and macrophage compared with current biomaterials used in the construction of glaucoma drainage devices. METHODS: Sample discs (n=6) of poly(methylmethacrylate), silicone, polypropylene, PTFE, and phosphorylcholine coated poly(methylmethacrylate) were seeded with fibrinogen, fibrin, fibroblast, and macrophages and incubated for variable lengths of time. The quantification was performed using radioactivity, spectrophotometry, ATP dependent luminometry, and immunohistochemistry respectively. RESULTS: Fibrinogen and fibrin adhesion to phosphorylcholine coated poly(methylmethacrylate) were significantly lower than PMMA (p=0.004). Phosphorylcholine coating of poly(methylmethacrylate) also significantly reduced the adhesion of human scleral fibroblast (p=0.002) and macrophage (p=0.01) compared with PMMA. All the other biomaterials showed either similar or insignificantly different levels of adhesion to all the proteins and cells tested compared with PMMA. CONCLUSION: Phosphorylcholine coating is a new material technology that offers considerable promise in the field of glaucoma drainage device development. (+info)
Hemodialysis-related lymphomononuclear release of interleukin-12 in patients with end-stage renal disease.
Interleukin-12 (IL-12) is a cytokine produced by peripheral blood mononuclear cells (PBMC) that causes interferon-gamma (IFN-gamma) production and enhancement of cell-mediated cytotoxicity. To clarify the role of hemodialysis biocompatibility on IL-12 production and uremic immunodeficiency, we have studied the IL-12 and IFN-gamma release by PBMC harvested from 12 patients dialyzed with cuprophan membrane (CU), eight patients dialyzed with polymethylmethacrylate membrane (PMMA), and eight nondialyzed uremic patients (UR). Ten healthy subjects constituted the control group (CON). PBMC were cultured for 48 h with and without nonspecific mitogen stimulation. In unstimulated conditions, CU showed an IL-12 PBMC production higher than CON, UR, and PMMA (46.67 +/- 30.13 versus 2.56 +/- 1.38, 6.16 +/- 7.09, and 4.62 +/- 4.76 pg/ml, respectively; P < 0.01). IL-12 production was correlated with C3a concentration measured at the outlet of hemodialyzer after 15 min of dialysis (r = 0.69, P < 0.01). IL-12 release in CU remained unchanged under mitogen stimulation (44.34 +/- 23.86 pg/ml) and was lower than in CON, UR, and PMMA (66.0 +/- 12.41, 68.37 +/- 25.78, and 67.75 +/- 22.61 pg/ml, respectively; P < 0.05). IFN-gamma production was similar, in unstimulated conditions, in all groups. Under stimulation, IFN-gamma release was lower in CU (13.42 +/- 12.04 IU/ml) than in CON, UR, and PMMA (51.84 +/- 30.74, 32.16 +/- 13.86, and 32.16 +/- 13.86 IU/ml, respectively; P < 0.01). These results demonstrate that hemodialysis with CU induces monocyte activation with an enhanced release of IL-12. On the contrary, stimulated PBMC production of both IL-12 and IFN-gamma is lower in these patients than in CON, UR, and PMMA. The altered release of these cytokines could play a role in cell-mediated immunodeficiency of the uremic patients dialyzed with CU. (+info)
Interaction of cisplatin with planar model membranes - dose dependent change in electrical characteristics.
The drug cisplatin has broad antineoplastic activity against advanced testicular and ovarian cancers, epithelial malignancies, cancers of the head, neck, bladder, oesophagus and lungs. Peripheral neurotoxicity, ototoxicity and nephrotoxicity are its major side effects. The nonspecific action of this drug on the lipid bilayer architecture of membranes has been studied by following the effects produced on the electrical characteristics of model planar bilayer lipid membranes (BLM). The results confirm that the drug has a strong surface interaction with the zwitterionic polar head groups of the amphipathic phospholipids constituting the BLM. The permeability characteristics of cisplatin through the hydrophobic core are limited. Cisplatin does not fluidise the membrane sufficiently to cause its breakdown but creates small ion conducting defects on the membrane bilayer resulting in a marginal increase in ion conductivity. These results indicate that cisplatin exhibits a non-specific action on the lipid bilayer component of the membrane which might be partly responsible for its neurotoxic side effects. (+info)
Macroporous polymer foams by hydrocarbon templating.
Porous polymeric media (polymer foams) are utilized in a wide range of applications, such as thermal and mechanical insulators, solid supports for catalysis, and medical devices. A process for the production of polymer foams has been developed. This process, which is applicable to a wide range of polymers, uses a hydrocarbon particulate phase as a template for the precipitation of the polymer phase and subsequent pore formation. The use of a hydrocarbon template allows for enhanced control over pore structure, porosity, and other structural and bulk characteristics of the polymer foam. Polymer foams with densities as low as 120 mg/cc, porosity as high as 87%, and high surface areas (20 m(2)/g) have been produced. Foams of poly(l-lactic acid), a biodegradable polymer, produced by this process have been used to engineer a variety of different structures, including tissues with complex geometries such as in the likeness of a human nose. (+info)
Control of staphylococcal adhesion to polymethylmethacrylate and enhancement of susceptibility to antibiotics by poloxamer 407.
We studied the antiadhesive effect of Poloxamer 407 (P407), together with modifications in the antimicrobial susceptibility of residual adherent staphylococci. Bacterial adherence was markedly inhibited (77% to more than 99.9%) whether polymethylmethacrylate was exposed to P407 before or during the adherence assay. Furthermore, residual adherent staphylococci appeared to be more susceptible to antibiotic activity, suggesting that combination of P407 with antibiotics could be a promising approach to the prevention of infection of foreign material. (+info)