Change of spontaneous reaction of glue and lipiodol mixture during embolization after the addition of tungsten powder: in vitro study.
(17/772)
BACKGROUND AND PURPOSE: We have noted that glue-Lipiodol mixtures harden prematurely in the catheter during embolization of brain arteriovenous malformations. However, we observed that hardening of this embolic material does not occur when tungsten powder is added to the glue mixture. In order to clarify the effect of tungsten powder on the glue mixture, we evaluated the reaction time and hardness of the glue mixture in vitro after the addition of tungsten powder. We also measured the pH of the tungsten solution. METHODS: Six lots of Lipiodol and three lots of Histoacryl Blue were mixed in a 5-cc bottle with a 50% to 25% glue concentration (glue:Lipiodol = 1:1 to 1:3) and this mixture was observed for 2 weeks. The hardness of the polymerized glue mixture was categorized as liquid, gel, semi-solid, or solid. Various series of experiments were performed after the addition of tungsten powder (0.2 g) and blood (a drop) into the glue mixture. We also separately mixed tungsten and tantalum powder in tubes, each with 5 mL of distilled water, and then measured the pH of these three times. The mixed amounts of tungsten and tantalum ranged from 0.1 to 0.5 mg. RESULTS: In a 50% glue concentration, the glue mixture turned into a solid cast within 48 hours. In a 25% concentration, the glue mixture turned into gel within 24 hours. The casts became solid in the 50% and gelled in the 25% concentration, and solid or gel in 28% and 33% glue mixture concentrations. The addition of tungsten powder to 50% and 25% glue mixture concentrations caused the glue mixtures to remain in a liquid state for 2 weeks regardless of the Lipiodol products used. Measurement of acidity achieved using a pH meter in 5 cc of distilled water with tungsten powder (0.1 to 0.5 g) revealed a change of pH from 3.5 to 2.6 according to the amount of tungsten added. Tantalum revealed weak acidity, with a pH range from 6.4 to 5.7. The addition of blood immediately caused the mixture to become solid in 50% and semi-solid in 25% glue concentrations. CONCLUSION: The reaction time of the glue mixture differed according to the lot number of the Lipiodol. The addition of tungsten powder appeared to prevent premature cast formation by decreasing the pH with a mechanism similar to that of adding acetic acid. (+info)
The consolidation and compressibility properties of some novel directly compressible filler-binders.
(18/772)
The aim of this study was to investigate the consolidation and compressibility properties and also the dilution potentials of some novel directly compressible filler-binders. For this purpose, Ludipress and Cellastose 80 (one-body compounds), Tablettose 70 and Tablettose 80 (alpha-mono agglomerated lactose) were selected. They were diluted at predetermined percentages with Spherolac 100 which is a coarse sieved hydrous crystalline lactose. The consolidation and compressibility properties of the prepared powder mixtures were determined. The experimental data were evaluated by using a computer programme (Basic 80). (+info)
Comparison of the efficacy and safety of mometasone furoate dry powder inhaler to budesonide Turbuhaler.
(19/772)
Mometasone furoate (MF) administered by dry powder inhaler (DPI) was composed with budesonide (BUD) Turbuhaler in the treatment of moderate persistent asthma. The patients were randomized to one of four treatment groups: MF DPI (100, 200, 400 microg b.i.d) or BUD Turbuhaler. 400 microg b.i.d in a 12-week, active-controlled, evaluator-blind, multicentre international trial. The primary efficacy variable was the mean change from baseline to endpoint (last treatment visit) in forced expiratory volume in one second (FEV1). Changes in FEV1 showed a statistically significant superiority (p<0.05) of MF DPI 200 and 400 microg b.i.d compared with the BUD Turbuhaler 400 microg b.i.d treatment. Significant superiority (p<0.05) was also seen in scores for several secondary efficacy variables when MF DPI was compared with BUD Turbuhaler treatment. MF DPI 200 microg b.i.d was comparable to MF DPI 400 microg b.i.d in therapeutic benefit. The incidence of oral candidiasis was no more than 3% in any group. All treatments were well tolerated. A total daily dose of 400 microg of mometasone furoate administered by dry powder inhaler provides a well-tolerated treatment for patients with moderate persistent asthma and results in a significantly greater improvement, when compared to a daily dose of 800 microg BUD Turbuhaler in the parameters measured in this study. (+info)
Neoplastic transformation of human osteoblast cells to the tumorigenic phenotype by heavy metal-tungsten alloy particles: induction of genotoxic effects.
(20/772)
Heavy metal-tungsten alloys (HMTAs) are dense heavy metal composite materials used primarily in military applications. HMTAs are composed of a mixture of tungsten (91-93%), nickel (3-5%) and either cobalt (2-4%) or iron (2-4%) particles. Like the heavy metal depleted uranium (DU), the use of HMTAs in military munitions could result in their internalization in humans. Limited data exist, however, regarding the long-term health effects of internalized HMTAs in humans. We used an immortalized, non-tumorigenic, human osteoblast-like cell line (HOS) to study the tumorigenic transforming potential of reconstituted mixtures of tungsten, nickel and cobalt (rWNiCo) and tungsten, nickel and iron (rWNiFe). We report the ability of rWNiCo and rWNiFe to transform immortalized HOS cells to the tumorigenic phenotype. These HMTA transformants are characterized by anchorage-independent growth, tumor formation in nude mice and high level expression of the K-ras oncogene. Cellular exposure to rWNiCo and rWNiFe resulted in 8.90 +/- 0.93- and 9.50 +/- 0.91-fold increases in transformation frequency, respectively, compared with the frequency in untreated cells. In comparison, an equivalent dose of crystalline NiS resulted in a 7.7 +/- 0.73-fold increase in transformation frequency. The inert metal tantalum oxide did not enhance HOS transformation frequency above untreated levels. The mechanism by which rWNiCo and rWNiFe induce cell transformation in vitro appears to involve, at least partially, direct damage to the genetic material, manifested as increased DNA breakage or chromosomal aberrations (i.e. micronuclei). This is the first report showing that HMTA mixtures of W, Ni and Co or Fe cause human cell transformation to the neoplastic phenotype. While additional studies are needed to determine if protracted HMTA exposure produces tumors in vivo, the implication from these in vitro results is that the risk of cancer induction from internalized HMTAs exposure may be comparable with the risk from other biologically reactive and insoluble carcinogenic heavy metal compounds (e.g. nickel subsulfide and nickel oxide). (+info)
In-vitro characterisation of metered dose inhaler versus dry powder inhaler glucocorticoid products: influence of inspiratory flow rates.
(21/772)
PURPOSE: To study the influence of inspiratory flow rate on the fine particle mass and the particle size distribution for metered dose inhaler (MDI) and dry powder inhaler (DPI) glucocorticoid products, in vitro. To compare the performance of MDI and DPI inhalers containing the same drug and strength at an impaction flow rate of 60 L/min. METHODS: The Marple Miller cascade impactor model 150 and 160 were used to characterise several glucocorticoid MDI and DPI products at different simulated inspiratory flow rates (30 L/min, 60 L/min and 90 L/min). Following the actuation of one single inhaler puff the amount of drug deposited in each stage of the impactor was quantified using high performance liquid chromatography with UV detection at 242 nm. The size distribution of the primary particles of DPI products was measured by laser diffraction. RESULTS: DPIs were significantly more dependent on impaction flow rate than MDIs. Except for Pulmicort(R), the fine particle mass FPM delivered from the MDI products was significantly higher than that delivered from the DPI aerosols. CONCLUSIONS: Although the metered dose inhaler is the older technology it exhibits greater respirable dose in vitro than newer dry powder inhaler devices. Care should be taken when shifting from one inhaler dosage form to another because this may affect the actual dose delivered to the lung. Further in vivo studies may be warranted in light of these findings. (+info)
Comparison of the systemic effects of fluticasone propionate and budesonide given by dry powder inhaler in healthy and asthmatic subjects.
(22/772)
BACKGROUND: The potential for long term adverse effects from inhaled corticosteroids relates to their systemic absorption, usually assessed from proxy markers in short term studies. When fluticasone propionate and budesonide have been compared in this way the results have been inconsistent. To determine whether this is because of the subjects studied or the sensitivity of the systemic marker used, we have compared the effects of fluticasone propionate and budesonide in healthy and asthmatic subjects and investigated the effect of treatment on three systemic markers. METHODS: Forty six healthy subjects were randomised to receive inhaled fluticasone propionate 1500 microg/day (via an Accuhaler), budesonide 1600 microg/day (via a Turbuhaler), or placebo; 31 subjects with moderately severe asthma were randomised to receive the same doses of fluticasone propionate or budesonide but not placebo. Systemic effects in healthy and asthmatic subjects were compared after 7 days. Treatment was continued for another 21 days in the subjects with asthma when systemic effects and asthma control were assessed. RESULTS: At baseline healthy subjects had higher urinary levels of total cortisol metabolites (TCM) than subjects with asthma. After 7 days of treatment with fluticasone propionate urinary TCM levels in the healthy subjects were significantly lower than in the subjects with asthma (mean difference between groups 1663 microg/day, 95% CI 328 to 2938). This was not the case with budesonide, however, where urinary TCM levels in the healthy subjects remained above those in the asthmatic subjects (mean difference between groups 1210 microg/day, 95% CI -484 to 2904). Urinary TCM levels were considerably more sensitive to the effects of inhaled corticosteroids than morning serum cortisol or osteocalcin concentrations. Only budesonide reduced the serum level of osteocalcin. CONCLUSIONS: When given by dry powder inhaler for 7 days, fluticasone propionate 1500 microg/day has a greater effect on the hypothalamic-pituitary-adrenal axis in healthy subjects than in subjects with asthma, but this is not the case for budesonide 1600 microg/day. These findings, together with the differences in sensitivity between systemic markers, explain many of the discrepancies in the literature. (+info)
Lung lesions induced by intratracheal instillation of vanadium pentoxide powder in rats.
(23/772)
To clarify acute toxicity and histopathological changes in the lung after exposure to V2O5 powder, rats (SD, male, n=66) were observed for 4 weeks after an intratracheal administration of V2O5 powder (geometric mean diameter 0.31 microm, geomertic standard deviation sigmag=2.19) at three doses (0.88, 3.0, 13.0 mg/kg body weight). The histopathological lung lesions were developed dose-dependently, and characterized by exudative inflammation, injury of alveolar macrophages, and swelling and mucous degeneration in the broncho-bronchiolar epithelia. Growth rate of the V2O5 powder-instilled rat was also retarded dose-dependently. The V2O5 powder used was composed of not coagulated but well dispersed particles consisting of vanadium pentoxide of more than 99.8% (w/w) with vanadium tetraoxide of less than 0.2%. The V2O5 powder was found to be 8 times more soluble in an artificial biological fluid "Gamble's solution" than in a pure water. From the present findings as well as those from the related literature, it was inferred that the histopathological lesions induced by the intratracheally instilled V2O5 powder are caused not only by the V2O5 particles per se but also by vanadium ions dissolved from the particles into the lung fluid. (+info)
Surface composition and structure of titanium polished with aqueous slurry of ferric oxide.
(24/772)
Cast plates were prepared from commercial titanium. The plates were polished with a slurry of fine ferric oxide powder. The surface composition and structure were investigated by electron probe microanalysis (EPMA) and X-ray photoelectron spectroscopy (XPS). In the high pressure-polished surface, iron was non-uniformly distributed but oxygen was mostly uniformly distributed, while in a light pressure-polished surface, iron and oxygen were uniformly distributed though at lower and higher concentrations, respectively. EPMA state analysis and XPS suggested that the iron might exist as Fe2+ in the outermost surface, while it might be in a metallic state in the inner surface layer. (+info)