Effects of gastric acid on euro coins: chemical reaction and radiographic appearance after ingestion by infants and children.
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OBJECTIVES: This study investigated whether coins of the new European currency (euro) corrode when they are exposed to gastric acid, and whether this change can be detected radiographically. METHODS: The eight different denominations of coins were immersed for seven days in 0.15 N hydrochloride acid (HCl), which corresponds to the level of post-prandial gastric acid. A Swedish crown coin and three different Austrian schilling coins were used as controls. The coins were weighed and radiographed daily to evaluate visible corrosions and HCl was analysed daily for possible dissolved substances. RESULTS: All coins lost weight within 24 hours after exposure to HCl. The 1, 2, and 5 euro cent coins developed changes that were visible on radiographs. The weights of all coins decreased by 0.43% to 11.30% during one week. The dissolved substances measured in the HCl corresponded to the different metals and alloys of the coins, except for copper, which does not dissolve in HCl. The highest absolute weight loss was observed in the Swedish crown coin (0.67 g), and the highest relative weight loss in the 1 Austrian schilling coin (11.30%). The two coins that showed the highest absolute and relative weight losses were the 2 euro (0.54 g or 6.35%) and the 1 euro (0.48 g or 6.39%) coin. CONCLUSIONS: A higher rate of toxicity for the new European coins compared with coins of other currencies is not expected, unless a massive coin ingestion occurs. (+info)
Is a metallic stent useful for non resectable esophageal cancer?
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A flexible nitinol stent was inserted to treat malignant stricture of the esophagus in 28 patients. Stenting was successful in all 28 patients, leading to an improved oral intake that was maintained for >80% of the survival period in 26 patients. Patients with tumors arising in the esophagus (n=24) were divided into two groups to compare complications and prognosis: patients who underwent stenting only (n=10); and patients who underwent stenting after radiochemotherapy (n=14). Fatal complications associated with stenting were seen in four patients (28.6%) who underwent stenting after radiochemotherapy and in one patient (10.0%) who underwent stenting only. Although survival was significantly longer for patients who underwent prior radiochemotherapy than for patients who did not, the incidence of fatal complications tended to be higher. No significant differences in background factors other than radiochemotherapy before stenting were observed between patients with fatal and non-fatal complications. Stenting was shown to represent a useful treatment for malignant stricture of the esophagus, as oral intake improved and was maintained for a long period of time in most patients. However, incidence of fatal complications was high among patients who underwent radiochemotherapy, and caution must be exercised due to the difficulty in predicting fatal complications. (+info)
MR safety and imaging of neuroform stents at 3T.
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The Neuroform stent is a self-expanding nitinol stent designed for use in wide-necked intracranial aneurysms. Heating and imaging artifacts were evaluated by using a porcine carotid artery aneurysm model in a 3T MR system. A suspended Neuroform stent was tested for deflection. No heating was measured, and no evidence of deflection of the stent was found. Imaging artifacts were minimal. MR imaging in patients with Neuroform stent-treated aneurysms is safe and feasible. (+info)
Fixation methods for implantable port chamber: comparative study using glue, self-stabilizing leg and suture fixations in rabbits.
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OBJECTIVE: To evaluate the fixation strength and tissue reaction of the glue fixation and self-stabilizing leg fixation methods and to compare the results with those of the conventional tagging suture fixation method. MATERIALS AND METHODS: Twelve healthy rabbits were selected and three different methods of implanting the port chamber were employed on the back of each rabbit. A total of thirty six port chambers were implanted with these three different methods, viz. the glue fixation method using tissue adhesive, the self-stabilizing leg method using a self-expandable stabilizing leg, and the suture fixation method. The fixation strength and the gross and histopathologic changes of each fixation method were evaluated at three days, one week, two weeks and four weeks after port implantation. RESULTS: The glue fixation method showed a good fixation strength, which was similar to that of the tagging suture method (p = 0.3486). Five of the six ports (83%) implanted with the glue fixation method which were examined after two weeks showed cracks on the external surface, but this had no adverse effects on their function. A large amount of granulation tissue reaction was found at the bottom of the chamber (p = 0.0025). The fixation with the self-stabilizing leg showed relatively lower fixation strength (p = 0.0043), but no turning-over of the chamber occurred. The fixation strength improved with time after the first week, and minimal granulation tissue reaction was observed with this method. CONCLUSION: The glue fixation method exhibited equal fixation strength compared to the suture fixation, but showed cracking and a large amount of granulation tissue, whereas the fixation with a self-stabilizing leg showed weaker fixation strength. (+info)
Prevalence and clinical impact of stent fractures after femoropopliteal stenting.
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OBJECTIVES: The aim of this study was to investigate the occurrence and the clinical impact of stent fractures after femoropopliteal stenting. BACKGROUND: The development of femoral stent fractures has recently been described; however, there are no data about the frequency and the clinical relevance. METHODS: A systematic X-ray screening for stent fractures was performed in 93 patients. In total, 121 legs treated by implantation of self-expanding nitinol stents were investigated after a mean follow-up time of 10.7 months. The mean length of the stented segment was 15.7 cm. RESULTS: Overall, stent fractures were detected in 45 of 121 treated legs (37.2%). In a stent-based analysis, 64 of 261 stents (24.5%) showed fractures, which were classified as minor (single strut fracture) in 31 cases (48.4%), moderate (fracture of >1 strut) in 17 cases (26.6%), and severe (complete separation of stent segments) in 16 cases (25.0%). Fracture rates were 13.2% for stented length < or =8 cm, 42.4% for stented length >8 to 16 cm, and 52.0% for stented length >16 cm. In 21 cases (32.8%) there was a restenosis of >50% diameter reduction at the site of stent fracture. In 22 cases (34.4%) with stent fracture there was a total stent reocclusion. According to Kaplan-Meier estimates, the primary patency rate at 12 months was significantly lower for patients with stent fractures (41.1% vs. 84.3%, p < 0.0001). CONCLUSIONS: There is a considerable risk of stent fractures after long segment femoral artery stenting, which is associated with a higher in-stent restenosis and reocclusion rate. (+info)
Effects of aluminum-copper alloy filtration on photon spectra, air kerma rate and image contrast.
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This study evaluated the performance of aluminum-copper alloy filtration, without the original aluminum filter, for dental radiography in terms of x-ray energy spectrum, air kerma rate and image quality. Comparisons of various thicknesses of aluminum-copper alloy in three different percentages were made with aluminum filtration. Tests were conducted on an intra-oral dental x-ray machine and were made on mandible phantom and on step-wedge. Depending on the thickness of aluminum-copper alloy filtration, the beam could be hardened and filtrated. The use of the aluminum-copper alloy filter resulted in reductions in air kerma rate from 8.40% to 47.33%, and indicated the same image contrast when compared to aluminum filtration. Aluminum-copper alloy filtration may be considered a good alternative to aluminum filtration. (+info)
Natural analcime zeolite modified with 5-Br-PADAP for the preconcentration and anodic stripping voltammetric determination of trace amount of cadmium.
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A procedure for separation and preconcentration of trace amounts of cadmium has been proposed. A column of analcime zeolite modified with benzyldimethyltetradecylammonium chloride and loaded with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) was used for retention of cadmium. The cadmium was quantitatively retained on the column at pH approximately 9 and was recovered from column with 5 ml of 2 M nitric acid with a preconcentration factor of 140. Anodic stripping differential pulse voltammetry was used for determination of cadmium. A 0.05 ng/ml detection limit for the preconcentration of aqueous solution of cadmium was obtained. The relative standard deviation (RSD) for eight replicate determinations at the 1 microg/ml cadmium levels was 0.31% (calculated with the peak height obtained). The calibration graph using the preconcentration system was linear from 0.01 to 150 microg/ml in final solution with a correlation coefficient of 0.9997. For optimization of conditions, various parameters such as the effect of pH, flow rate, instrumental conditions and interference of number of ions, were studied in detail. This method was successfully applied for determination of cadmium in various complex samples. (+info)
Continuing concern regarding the potential health and environmental effects of depleted uranium and lead has resulted in many countries adding tungsten alloy (WA)-based munitions to their battlefield arsenals as replacements for these metals. Because the alloys used in many munitions are relatively recent additions to the list of militarily relevant metals, very little is known about the health effects of these metals after internalization as embedded shrapnel. Previous work in this laboratory developed a rodent model system that mimicked shrapnel loads seen in wounded personnel from the 1991 Persian Gulf War. In the present study, we used that system and male F344 rats, implanted intramuscularly with pellets (1 mm times 2 mm cylinders) of weapons-grade WA, to simulate shrapnel wounds. Rats were implanted with 4 (low dose) or 20 pellets (high dose) of WA. Tantalum (20 pellets) and nickel (20 pellets) served as negative and positive controls, respectively. The high-dose WA-implanted rats (n = 46) developed extremely aggressive tumors surrounding the pellets within 4-5 months after implantation. The low-dose WA-implanted rats (n = 46) and nickel-implanted rats (n = 36) also developed tumors surrounding the pellets but at a slower rate. Rats implanted with tantalum (n = 46), an inert control metal, did not develop tumors. Tumor yield was 100% in both the low- and high-dose WA groups. The tumors, characterized as high-grade pleomorphic rhabdomyosarcomas by histopathology and immunohistochemical examination, rapidly metastasized to the lung and necessitated euthanasia of the animal. Significant hematologic changes, indicative of polycythemia, were also observed in the high-dose WA-implanted rats. These changes were apparent as early as 1 month postimplantation in the high-dose WA rats, well before any overt signs of tumor development. These results point out the need for further studies investigating the health effects of tungsten and tungsten-based alloys. (+info)