Increase in national intravenous thrombolysis rates for ischaemic stroke between 2005 and 2012: is bigger better?

BACKGROUND: Intravenous thrombolytic therapy after ischaemic stroke significantly reduces mortality and morbidity. Actual thrombolysis rates are disappointingly low in many western countries. It has been suggested that higher patient volume is related to shorter door-to-needle-time (DNT) and increased thrombolysis rates. We address a twofold research question: a) What are trends in national thrombolysis rates and door-to-needle times in the Netherlands between 2005-2012? and b) Is there a relationship between stroke patient volume per hospital, thrombolysis rates and DNT? METHODS: We used data from the Stroke Knowledge Network Netherlands dataset. Information on volume, intravenous thrombolysis rates, and admission characteristics per hospital is acquired through yearly surveys, in up to 65 hospitals between January 2005 and December 2012. We used linear regression to determine a possible relationship between hospital stroke admission volume, hospital thrombolysis rates and mean hospital DNT, adjusted for patient characteristics. RESULTS: Information on 121.887 stroke admissions was available, ranging from 7.393 admissions in 2005 to 24.067 admissions in 2012. Mean national thrombolysis rate increased from 6.4% in 2005 to 14.6% in 2012. Patient characteristics (mean age, gender, type of stroke) remained stable. Mean DNT decreased from 72.7 min in 2005 to 41.4 min in 2012. Volume of stroke admissions was not an independent predictor for mean thrombolysis rate nor for mean DNT. CONCLUSION: Intravenous thrombolysis rates in the Netherlands more than doubled between 2005 and 2012, in parallel with a large decline in mean DNT. We found no convincing evidence for a relationship between stroke patient volume per hospital and thrombolysis rate or DNT.

CT of metal implants: reduction of artifacts using an extended CT scale technique.

PURPOSE: The purpose of this work was to use an extended CT scale technique (ECTS) to reduce artifacts due to metal implants and to optimize CT imaging parameters for metal implants using an experimental model. METHOD: Osteotomies were performed in 20 porcine femur specimens. One hundred cobalt-base screws and 24 steel plates were used for osteosynthesis in these specimens. Artificial lesions were produced in 50 screws, such as osteolysis near the screws (mimicking lysis due to infection, tumor, or loosening), displacement of the screws, as well as fractures of the screws. All specimens were examined using eight different CT protocols: four conventional (CCT) and four spiral (SCT) CT protocols with different milliampere-second values (130 and 480 mAs for CCT, 130 and 300 mAs for SCT), kilovolt potentials (120 and 140 kVp), and slice thicknesses (2 and 5 mm). The images were analyzed by three observers using a standard window (maximum window width 4,000 HU) and ECTS (maximum window width 40,000 HU). Receiver operating characteristic analysis was performed, and image quality was assessed according to a five level scale. RESULTS: Metal artifacts were significantly reduced using ECTS (p < 0.05). The highest diagnostic performance was obtained using ECTS with the thinnest slice thickness. Metal artifacts were more pronounced using SCT. In this experimental model, exposure dose and kilovolt potential had no significant impact on diagnostic performance (p > 0.05). CONCLUSION: ECTS improved imaging of metal implants. In this study, no significant effects of exposure dose and kilovolt potential were noted. Metal artifacts were more prominent using SCT than using CCT.

Effects of endocrine disruptors on prosobranch snails (Mollusca: Gastropoda) in the laboratory. Part II: Triphenyltin as a xeno-androgen.

In laboratory experiments the effects of suspected endocrine disrupting chemicals on freshwater and marine prosobranch species were analysed. In this second of three publications the responses of the freshwater ramshorn snail Marisa cornuarietis and of two marine prosobranchs (the dogwhelk Nucella lapillus and the netted whelk Hinia reticulata) to the xeno-androgenic model compound triphenyltin (TPT) are presented. Marisa and Nucella were exposed via water (nominal concentrations 5-500 ng TPT-Sn/L) and Hinia via sediments (nominal concentrations 50-500 micrograms TPT-Sn/kg dry wt.) for up to 4 months. Female ramshorn snails but not the two marine species developed imposex in a time and concentration dependent manner (EC10 4 months: 12.3 ng TPT-Sn/L) with a comparable intensity as described for tributyltin. TPT reduced furthermore the fecundity of Marisa at lower concentrations (EC10 4 months: 5.59 ng TPT-Sn/L) with a complete inhibition of spawning at nominal concentrations > or = 250 ng TPT-Sn/L (mean measured +/- SD: > or = 163 +/- 97.0 ng TPT-Sn/L). The extension of the pallial sex organs (penis with accessory structures and prostate gland) of male ramshorn snails and dogwhelks were reduced by up to 25% compared to the control but not in netted whelks. Histopathological analyses for M. cornuarietis and H. reticulata provide evidence for a marked impairment of spermatogenesis (both species) and oogenesis (only netted whelks). The test compound induced a highly significant and concentration independent increase in the incidence of hyperplasia on gills, osphradia and other organs in the mantle cavity of N. lapillus indicating a carcinogenic potential of TPT. The results show that prosobranchs are sensitive to endocrine disruption at environmentally relevant concentrations of TPT. Also, M. cornuarietis is a promising candidate for a future organismic invertebrate system to identify endocrine-mimetic test compounds.