Carotid artery vasoreactivity correlates with abdominal aortic vasoreactivity in young healthy individuals but not in patients with abdominal aortic aneurysm.

Background: Sympathetic stimulation of central arteries, such as coronary and carotid arteries, cause vasodilation in healthy subjects, but vasoconstriction in those with increased cardiovascular risk. This study compared vasoreactivity to sympathetic stimulation between abdominal aorta and carotid artery in healthy young individuals (young group, n = 20), in patients with abdominal aortic aneurysm (AAA group, n = 20) and in a healthy older group, age- and gender matched with AAA group (matched group, n = 18). Method: All subjects underwent cold pressor test, while performing concomitantly duplex ultrasound of abdominal aorta and carotid artery vasoreactivity. Observer-independent software was used to analyze and calculate magnitude and timing of maximum vasodilation or vasoconstriction. Pearson's correlation coefficient was calculated to investigate vasoreactivity between arteries. Results: Carotid artery reactivity [Interquartile range 25%, Interquartile range 75%] did not significantly differ between the young, matched and AAA group (3.5% [1.4, 4.7], 2.6% [2.0, 4.1] and 2.2% [-1.9, 3.7], respectively, p = 0.301). Abdominal aortic responsiveness demonstrated larger differences between young (4.9% [-0.2, 8.4]), matched (3.3% [-2.5, 4.4]) and individuals with AAA (0.5% [-3.9, 4.1], p = 0.059). Pooled analysis showed a significant correlation between carotid and abdominal aortic vasoreactivity (r = 0.444, p = 0.001). Subgroup analyses demonstrated significant correlation between both arteries in young (r = 0.636, p = 0.003), but not matched (r = −0.040, p = 0.866) or AAA group (r = 0.410, p = 0.129). Conclusions: Sympathetic stimulation induces powerful vasodilation of the carotid artery and abdominal aorta, which is significantly correlated in healthy individuals. No such correlation is present in abdominal aortic aneurysm patients. This suggests the aneurysm alters local abdominal aorta vasoreactivity, but not the carotid artery

The development of instruments to measure the work disability assessment behaviour of insurance physicians

<p>Abstract</p> <p>Background</p> <p>Variation in assessments is a universal given, and work disability assessments by insurance physicians are no exception. Little is known about the considerations and views of insurance physicians that may partly explain such variation. On the basis of the Attitude - Social norm - self Efficacy (ASE) model, we have developed measurement instruments for assessment behaviour and its determinants.</p> <p>Methods</p> <p>Based on theory and interviews with insurance physicians the questionnaire included blocks of items concerning background variables, intentions, attitudes, social norms, self-efficacy, knowledge, barriers and behaviour of the insurance physicians in relation to work disability assessment issues. The responses of 231 insurance physicians were suitable for further analysis. Factor analysis and reliability analysis were used to form scale variables and homogeneity analysis was used to form dimension variables. Thus, we included 169 of the 177 original items.</p> <p>Results</p> <p>Factor analysis and reliability analysis yielded 29 scales with sufficient reliability. Homogeneity analysis yielded 19 dimensions. Scales and dimensions fitted with the concepts of the ASE model. We slightly modified the ASE model by dividing behaviour into two blocks: behaviour that reflects the assessment process and behaviour that reflects assessment behaviour.</p> <p>The picture that emerged from the descriptive results was of a group of physicians who were motivated in their job and positive about the Dutch social security system in general. However, only half of them had a positive opinion about the Dutch Work and Income (Capacity for Work) Act (WIA). They also reported serious barriers, the most common of which was work pressure. Finally, 73% of the insurance physicians described the majority of their cases as 'difficult'.</p> <p>Conclusions</p> <p>The scales and dimensions developed appear to be valid and offer a promising basis for future research. The results suggest that the underlying ASE model, in modified form, is suitable for describing the assessment behaviour of insurance physicians and the determinants of this behaviour. The next step in this line of research should be to validate the model using structural equation modelling. Finally, the predictive value should be tested in relation to outcome measurements of work disability assessments.</p

REDUCTION OF CISPLATIN NEPHROTOXICITY BY SODIUM SELENITE - LACK OF INTERACTION AT THE PHARMACOKINETIC LEVEL OF BOTH COMPOUNDS

Administration of sodium selenite (Na2SeO3) 1 hr before cis-diamminedichloroplatinum(II) (referred to herein as cisplatin) can protect against the nephrotoxicity of cisplatin. The pharmacokinetic aspects of this interaction were studied in rodents with radiolabeled selenite and cisplatin. Total [75Se]selenium in plasma consisted of [75Se] selenium in plasma proteins and [75Se]selenite in plasma ultrafiltrate. After a short distribution phase, the elimination of [75Se]selenite and total [75Se]selenium proceeded biphasically in the rat, with an initial plasma elimination half-life of [75Se]selenite of 22 +/- 2 min. Coadministration of cisplatin had no effect on the initial nor on the much slower terminal elimination phase of [75Se]selenite nor of total [75Se] selenium. Sodium selenite, in doses protecting against the nephrotoxicity of cisplatin, did not significantly affect areas under the plasma concentration time curve from 0-6 hr nor the initial plasma half-lives of [195mPt]cisplatin (t1/2, 28 +/- 2 min) and total [195mPt]platinum (t1/2, 30 +/- 3 min) in plasma. The much slower terminal elimination phases in plasma and the cumulative urinary excretion of [195mPt] cisplatin and total [195mPt]platinum were neither influenced by sodium selenite. Sodium selenite does not react chemically with cisplatin in vitro. Apparently, bioactivation of selenite is required for its protective effect in vivo. Distribution studies in a mice tumor model indicated that [75Se]selenium is concentrated strongly in the kidney and that the bioactivation of selenite also most likely occurs primarily in the kidneys. We conclude that sodium selenite protects rodents against cisplatin-induced nephrotoxicity without influencing the systemic availability of cisplatin and total platinum.(ABSTRACT TRUNCATED AT 250 WORDS

A systematic review summarizing local vascular characteristics of the aneurysm wall to predict progression and rupture risk of abdominal aortic aneurysms.

Objective: Rupture risk prediction of abdominal aortic aneurysms (AAA), and hence clinical decision making on the need for surgery, is currently based on AAA diameter and growth rate. Unfortunately, these measures provide limited predictive information. This study summarized measures of local vascular characteristics of the aneurysm wall that, independent of AAA size, could predict AAA progression and AAA rupture. Method: Pubmed and Web of Science were systematically searched up to September 13th, 2021 to identify relevant articles investigating the relationship between local vascular characteristics of the aneurysm wall and AAA growth or rupture in humans. Quality assessment was performed with the ROBINS-I tool. All included articles were divided in four types of measure of arterial wall characteristics; metabolism, calcification, intraluminal thrombus and compliance. Results: Twenty articles were included. Metabolism of the aneurysm wall, especially measured with ultra-small superparamagnetic iron oxide uptake, and calcification were significantly related to AAA growth. Higher intraluminal thrombus volume and thickness was in one study positively correlated to AAA growth and in another study negatively correlated. AAA compliance demonstrated no correlation with AAA growth and rupture. Aneurysmal wall characteristics showed no association with AAA rupture. However, metabolism measured by ultra-small superparamagnetic iron oxide uptake, but none of the other measures, showed a trend toward a relation to AAA rupture, although not statistically significant. Conclusion: Current measures of aortic wall characteristics have potential to predict AAA growth, especially measuring metabolism and calcification. Evidence regarding AAA rupture is scarce and although more work is needed, aortic wall metabolism could potentially be related to AAA rupture. This highlights the role of aortic wall characteristics in the progression of AAA, but also the potential to improve prediction of AAA growth and rupture

Bronnen, regionale schaling en validatie van methaanemissies uit Nederland en Noord-West Europa

Abstract niet beschikbaarThe agreed emission reductions in the Kyoto Protocol require methods to establish the quality and accuracy of the inventory data and to monitor compliance with the Protocol. The IPCC Expert Meeting in November 1997 in the Netherlands concluded that an assessment of inventory data quality was strongly supported by independent checks and additional analysis of uncertainties in the emissions inventories. In this study, carried out in the frame of the Dutch National Research Programme on Global Air Pollution and Climate Change three connected validation procedures have been applied for a methane emission inventory, namely (i) the comparison of emission inventories, (ii) the comparison of modelled with observed methane concentrations, and (iii) the comparison of bottom-up emission estimates with inversely modelled emission estimates. There is a good overall correspondence between the consistent bottom-up METDAT emission inventory and the National Communication data. However, on a country level and on a source category level large discrepancies could been found. The analysis of concentration measurements gives a clear indication of the contribution from the different areas. Time series analysis as such appeared not to be suitable for verification purposes in this study. The technique of emission verification by modelling methane concentrations with the bottom-up estimated emission data as input for the model and comparing the results with measured concentrations has been proven quite successful, at least on a regional scale. The technique applied so far is however not able to indicate whether the individual sources are estimated realistically as well. At present, the technique of inverse modelling has not proven to be robust enough to produce stable results of satisfactory accuracy on a regional scale. At least, there is a lack of sufficient measurement data, e.g. from neighbouring countries and a need for the improvement of background concentration data (by global models).SG-NO