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  • Cardiac Radiology  (2)
  • Renin angiotensin aldosterone system  (1)
  • Renin-Angiotensin-Aldosteron-System  (1)
  • mitochondrial respiration  (1)
  • 1
    Publication Date: 2012-10-24
    Description: Purpose: To develop and validate a technique for near-automated definition of myocardial regions of interest suitable for perfusion evaluation during vasodilator stress cardiac magnetic resonance (MR) imaging. Materials and Methods: The institutional review board approved the study protocol, and all patients provided informed consent. Image noise density distribution was used as a basis for endocardial and epicardial border detection combined with nonrigid registration. This method was tested in 42 patients undergoing contrast material–enhanced cardiac MR imaging (at 1.5 T) at rest and during vasodilator (adenosine or regadenoson) stress, including 15 subjects with normal myocardial perfusion and 27 patients referred for coronary angiography. Contrast enhancement–time curves were near–automatically generated and were used to calculate perfusion indexes. The results were compared with results of conventional manual analysis, using quantitative coronary angiography results as a reference for stenosis greater than 50%. Statistical analyses included the Student t test, linear regression, Bland-Altman analysis, and statistics. Results: Analysis of one sequence required less than 1 minute and resulted in high-quality contrast enhancement curves both at rest and stress (mean signal-to-noise ratios, 17 ± 7 [standard deviation] and 22 ± 8, respectively), showing expected patterns of first-pass perfusion. Perfusion indexes accurately depicted stress-induced hyperemia (increased upslope, from 6.7 sec –1 ± 2.3 to 15.6 sec –1 ± 5.9; P 〈 .0001). Measured segmental pixel intensities correlated highly with results of manual analysis ( r = 0.95). The derived perfusion indexes also correlated highly with ( r up to 0.94) and showed the same diagnostic accuracy as manual analysis (area under the receiver operating characteristic curve, up to 0.72 vs 0.73). Conclusion: Despite the dynamic nature of contrast-enhanced image sequences and respiratory motion, fast near-automated detection of myocardial segments and accurate quantification of tissue contrast is feasible at rest and during vasodilator stress. This technique, shown to be as accurate as conventional manual analysis, allows detection of stress-induced perfusion abnormalities. © RSNA, 2012 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12112475/-/DC1
    Keywords: Cardiac Radiology
    Print ISSN: 0033-8419
    Electronic ISSN: 1527-1315
    Topics: Medicine
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  • 2
    Publication Date: 2012-07-21
    Description: Purpose: To test the hypothesis that magnetic resonance (MR) imaging R1 (R1 = 1/T1) mapping after selectively labeling monocytes with a T1-shortening contrast agent in vivo would enable the quantitative measurement of their spatiotemporal kinetics in the setting of infarct healing. Materials and Methods: All procedures were performed in mice and were approved by the institutional committee on animal research. One hundred microliters of dual-labeled liposomes (DLLs) containing gadolinium (Gd)-diethylenetriaminepentaacetic acid (DTPA)-bis(stearylamide) and DiI dye were used to label monocytes 2 days before myocardial infarction (MI). MI was induced by occlusion of the left anterior descending coronary artery for 1 hour, followed by reperfusion. MR imaging R1 mapping of mouse hearts was performed at baseline on day –3, on day 0 before MI, and on days 1, 4, and 7 after MI. Mice without labeling were used as controls. R1 was calculated as the difference in R1 between mice with labeling and those without labeling. CD68 immunohistochemistry and DiI fluorescence microscopy were used to confirm that labeled monocytes and/or macrophages infiltrated the postinfarct myocardium. Statistical analysis was performed by using two-way analysis of variance and the unpaired two-sample t test. Results: Infarct zone R1 was slightly but nonsignificantly increased on day 1, maximum on day 4 ( P 〈 .05 vs all other days), and started to decrease by day 7 ( P 〈 .05 vs days –3, 0, and 1) after MI, closely reflecting the time course of monocyte and/or macrophage infiltration of the infarcted myocardium shown by prior histologic studies. Histologic results confirmed the presence and location of DLL-labeled monocytes and/or macrophages in the infarct zone on day 4 after MI. Conclusion: R1 mapping after labeling monocytes with T1-shortening DLLs enables the measurement of post-MI monocyte and/or macrophage spatiotemporal kinetics. © RSNA, 2012 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12111863/-/DC1
    Keywords: Cardiac Radiology
    Print ISSN: 0033-8419
    Electronic ISSN: 1527-1315
    Topics: Medicine
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  • 3
    ISSN: 1432-1440
    Keywords: Essential hypertension ; Renin angiotensin aldosterone system ; Bodyweight ; Blood pressure in childhood ; Essentielle Hypertonie ; Renin-Angiotensin-Aldosteron-System ; Körpergewicht ; Blut-druck beim Kind
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung In der vorliegenden Untersuchung wurden 294 Nachkommen (5–34 Jahre) essentieller Hypertoniker bezüglich Blutdruck, Renin-Angiotensin-Aldosteron-System and anderer kardiovaskulärer Risikofaktoren wie Glukose, Cholesterin und Triglyzeride untersucht und mit 122 Nachkommen (5–34 Jahre) normotoner Eltern verglichen. Dabei zeigte sich, daß Nachkommen essentieller Hypertoniker im Mittel statistisch signifikant höhere systolische und diastolische Blutdruckwerte zeigten als solche normotoner Eltern (p〈0,003 bzw. 0,005). Weiter ließ sich bei Kindern hypertoner Eltern im Mittel ein signifikant höheres Körpergewicht und ein größerer Body-Mass-Index beobachten als im Kontrollkollektiv (p〈0,006 bzw. 0,001). Mit Ausnahme statistisch signifikant niedrigerer Ruhe-Plasma-Aldosteronwerte (p〈0,002) bei Kindern essentieller Hypertoniker ließen sich zwischen beiden Kollektiven keine Unterschiede im Stimulationsaldosteron, in der Ruhe- und Stimulations-Plasma-Renin-Aktivität und im Plasmacortisol nachweisen. Ebenfalls zeigten die beiden Kollektive bezüglich der anderen untersuchten Parametern wie Kreatinin, Glukose, Cholesterin und Triglyzeride keine wesentlichen Unterschiede. Weiterhin wurden in der vorliegenden Untersuchung 41 hypertone Elternteile, 65 (normotone) Ehepartner von Hypertonikern und 47 (normotone) Eltern von Kontrollkindern untersucht. Erwarungsgemäß zeigten Hypertoniker statistisch signifikant höhere Blutdruckwerte als ihre Ehepartner und die Kontrolleltern (p〈0,001). Interessanterweise zeigten die hypertonen Eltern nicht nur einen höheren Body-Mass-Index als Kontrolleltern sondeern auch als Ehepartner (p〈0,01 bzw. 〈0,02). Diese Befunde stützen eine vorwiegend genetische Disposition als zugrundeliegende Ursache des höheren Körpergewichtsverhaltens und lassen eine vermehrte Nahrungsmittelaufnahme in Hypertonikerfamilien eher als unwahrscheinlich erscheinen. Die Ergebnisse der vorliegenden Studie legen es nahe, daß durch eine möglichst frühzeitige Kontrolle des Körpergewichtsverhaltens bei Nachkommen essentieller Hypertoniker ein Beitrag zur Primärprävention der Hochdruckkrankheit geleistet werden kann.
    Notes: Summary In the present study, blood pressure, the renin angiotensin aldosterone system, and other cardiovascular risk factors, such as glucose, cholesterine, and triglycerides, were investigated in 294 offspring of essential hypertensives (5–34 years) and in 122 children of normotensive parents (5–34 years). Offspring of essential hypertensives showed statistically significant higher systolic and diastolic blood pressure values than those of normotensive parents (p〈0.003, 〈0.005, respectively). Furthermore, in children of hypertensive parents a statistically significant higher body weight and body mass index than in controls could be observed (p〈0.006, 〈0.001, respectively). With the exception of statistically significant, lower mean supine plasma aldosterone values (p〈0.02) in children of hypertensive parents, no major differences between the two groups were seen in stimulated aldosterone, supine and stimulated plasma renin activity, and plasma cortisol. Furthermore, in the present study, 41 hypertensive parents, 65 (normotensive) spouses of hypertensives, and 47 (normotensive) parents of control children were investigated. As expected, hypertensive parents showed statistically significant higher blood pressure values than parents of control children and their spouses (p〈0.001). Interestingly, hypertensive parents had not only a higher body mass index than control parents but also than their spouses (p〈0.01 and 〈0.02, respectively). These findings support a genetic disposition as being the underlying cause of higher body weight in hypertensives and make it less probable that a higher food intake in hypertensive families is responsible for this phenomenon. The results of the present study indicate that early body weight control in children of hypertensive parents may be an important contribution to the prevention of hypertension.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 42 (1986), S. 570-572 
    ISSN: 1420-9071
    Keywords: Anoxic injury ; mitochondrial respiration ; renal medulla ; acute renal failure ; renal metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In brain1, heart2 and kidney3, cell work in the absence of oxygen has been thought to precipitate anoxic damage by increasing the rate of depletion of cellular energy stores. In the medullary thick ascending limb of isolated perfused rat kidneys, however, reduction of ATP synthesis by a variety of mitochondrial or metabolic inhibitors caused ATP depletion comparable to that produced by oxygen deprivation but did not reproduce the lesions of anoxia. In these cells, unrestrained mitochondrial activity may be an important source of anoxic injury.
    Type of Medium: Electronic Resource
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