Afbeeldingskwaliteit van röntgendiagnostische systemen: Gereedschappen voor de klinisch fysische praktijk

Röntgenstraling wordt, na de ontdekking op 8 november 1895 door W.C. Röntgen, al meer dan honderd jaar ten behoeve van de diagnostiek in de geneeskunde toegepast. Hoewel de gevaren van deze straling reeds vroeg bekend waren en er al snel meetmethoden tcr beschikking stonden om de intensiteit van de straling te meten, duurde het ongeveer dertig jaar, voordat er redelijk stralen hygiënisch werd gewerkt en er daadwerkelijk gebruik gemaakt werd van deze meetmethoden. De eerste dertig jaar na de ontdekking van röntgenstraling bestond er op dosimetriegebied een chaotische situatie: er waren vele meetmethoden in gebruik, variërend van de bepaling van de tijd waarin de beharing van de huid was verdwenen (epilatiedosisl, tot de indirecte bepaling van het aantal ionisaties in gassen. Artsen prefereerden in het algemeen meetmethoden die een fysiologische ba'iis hadden. De erytheemdosis, de dosis waarbij de huid rood wordt. was het meest populair. Dit was echter geen nauwkeurige maat voor de toegevoegde stralingsdosis: atbankelijk van de omstandigheden van de proefpersoon kon de erytheemdosis een factor tien variëren

Consensus Democracy and Bureaucracy in the Low Countries

The politics and administration of institutional chang

High Resolution Spectroscopy of the X-ray Photoionized Wind in Cygnus X-3 with the Chandra High Energy Transmission Grating Spectrometer

We present a preliminary analysis of the 1--10 keV spectrum of the massive X-ray binary Cyg X-3, obtained with the High Energy Transmission Grating Spectrometer on the Chandra X-ray Observatory. The source reveals a richly detailed discrete emission spectrum, with clear signatures of photoionization-driven excitation. Among the spectroscopic novelties in the data are the first astrophysical detections of a number of He-like 'triplets' (Si, S, Ar) with emission line ratios characteristic of photoionization equilibrium, fully resolved narrow radiative recombination continua of Mg, Si, and S, the presence of the H-like Fe Balmer series, and a clear detection of a ~ 800 km/s large scale velocity field, as well as a ~1500 km/s FWHM Doppler broadening in the source. We briefly touch on the implications of these findings for the structure of the Wolf-Rayet wind.Comment: 11 pages, 3 figures; Accepted for publication in ApJ Letter

Factor V Leiden mutation, prothrombin gene mutation, and deficiencies in coagulation inhibitors associated with Budd-Chiari syndrome and portal vein thrombosis: results of a case-control study

In a collaborative multicenter case-control study, we investigated the effect of factor V Leiden mutation, prothrombin gene mutation, and inherited deficiencies of protein C, protein S, and antithrombin on the risk of Budd-Chiari syndrome (BCS) and portal vein thrombosis (PVT). We compared 43 BCS patients and 92 PVT patients with 474 population-based controls. The relative risk of BCS was 11.3 (95% CI 4.8-26.5) for individuals with factor V Leiden mutation, 2.1(95% CI 0.4-9.6) for those with prothrombin gene mutation, and 6.8 (95% CI 1.9-24.4) for those with protein C deficiency. The relative risk of PVT was 2.7 (95% CI 1.1-6.9) for individuals with factor V Leiden mutation, 1.4 (95% CI 0.4-5.2) fo

Angptl4 Protects against Severe Proinflammatory Effects of Saturated Fat by Inhibiting Fatty Acid Uptake into Mesenteric Lymph Node Macrophages

SummaryDietary saturated fat is linked to numerous chronic diseases, including cardiovascular disease. Here we study the role of the lipoprotein lipase inhibitor Angptl4 in the response to dietary saturated fat. Strikingly, in mice lacking Angptl4, saturated fat induces a severe and lethal phenotype characterized by fibrinopurulent peritonitis, ascites, intestinal fibrosis, and cachexia. These abnormalities are preceded by a massive acute phase response induced by saturated but not unsaturated fat or medium-chain fat, originating in mesenteric lymph nodes (MLNs). MLNs undergo dramatic expansion and contain numerous lipid-laden macrophages. In peritoneal macrophages incubated with chyle, Angptl4 dramatically reduced foam cell formation, inflammatory gene expression, and chyle-induced activation of ER stress. Induction of macrophage Angptl4 by fatty acids is part of a mechanism that serves to reduce postprandial lipid uptake from chyle into MLN-resident macrophages by inhibiting triglyceride hydrolysis, thereby preventing macrophage activation and foam cell formation and protecting against progressive, uncontrolled saturated fat-induced inflammation

Rosuvastatin use reduces thrombin generation potential in patients with venous thromboembolism: a randomized controlled trial

Background Statin therapy could form an alternative prophylactic treatment for venous thromboembolism (VTE) if statins are proven to downregulate hemostasis and prevent recurrent VTE, without increasing bleeding risk. Objectives The STAtins Reduce Thrombophilia (START) trial investigated whether statin affects coagulation in patients with prior VTE. Patients/methods After anticoagulation withdrawal, patients were randomized to rosuvastatin 20 mg day−1 for 4 weeks or no intervention. Plasma samples taken at baseline and at the end of the study were analyzed employing thrombin generation assay. Results and conclusions The study comprised 126 rosuvastatin users and 119 non‐users. Mean age was 58 years, 61% were men, 49% had unprovoked VTE and 75% had cardiovascular (CV) risk factors. Endogenous thrombin potential (ETP) increased from baseline to end of study in non‐statin users (mean 97.22 nm*min; 95% CI, 40.92–153.53) and decreased in rosuvastatin users (mean −24.94 nm*min; 95% CI, −71.81 to 21.93). The mean difference in ETP change between treatments was −120.24 nm*min (95% CI, −192.97 to −47.51), yielding a 10.4% ETP reduction by rosuvastatin. The thrombin peak increased in both non‐statin (mean 20.69 nm; 95% CI, 9.80–31.58) and rosuvastatin users (mean 8.41 nm; 95% CI −0.86 to 17.69). The mean difference in peak change between treatments was −11.88 nm (95% CI, −26.11 to 2.35), yielding a 5% peak reduction by rosuvastatin. Other thrombin generation parameters did not change substantially. The reduction in ETP and peak by rosuvastatin was more pronounced in the subgroups of participants with CV risk factors and with unprovoked VTE. We conclude that rosuvastatin reduces thrombin generation potential in patients who had VTE