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https://www.readbyqxmd.com/read/28619736/effects-of-hypercapnia-on-myocardial-blood-flow-in-healthy-human-subjects
#1
Matthieu Pelletier-Galarneau, Robert A deKemp, Chad Rrn Hunter, Ran Klein, Michael Klein, Joel Ironstone, Joseph A Fisher, Terrence Ruddy
Background: Elevation of end-tidal partial pressure of CO2 (PETCO2) increases cerebral and myocardial blood flow (MBF), suggesting that it may be a suitable alternative to pharmacological stress or exercise for myocardial perfusion imaging. The purpose of this study was to document the pharmacodynamics of CO2 on MBF using prospective end-tidal targeting to precisely control arterial PCO2 and use positron emission tomography (PET) to measure the outcome variable, MBF Methods: 10 healthy males underwent serial (82)Rb PET/CT imaging...
June 15, 2017: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
https://www.readbyqxmd.com/read/28611245/optimization-of-spect-measurement-of-myocardial-blood-flow-with-corrections-for-attenuation-motion-and-blood-binding-compared-to-pet
#2
R Glenn Wells, Brian Marvin, Marlie Poirier, Jennifer M Renaud, Robert A deKemp, Terrence D Ruddy
Myocardial blood flow (MBF) and flow reserve (MFR) measured with positron emission tomography (PET) have clinical value. Single-photon emission computed tomography (SPECT) cameras with solid-state detectors can obtain dynamic images for measurement of MBF and MFR. In this study, SPECT measurements of MBF made using (99m)Tc-tetrofosmin were compared to PET in the same patients. Methods: Thirty-one patients had PET MBF rest-stress studies performed with (82)Rb or (13)N- ammonia within one month of their SPECT...
June 13, 2017: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
https://www.readbyqxmd.com/read/28600102/physiologic-mechanism-of-discordance-between-instantaneous-wave-free-ratio-and-fractional-flow-reserve-insight-from-13-n-ammonium-positron-emission-tomography
#3
Joo Myung Lee, Doyeon Hwang, Jonghanne Park, Yaliang Tong, Bon-Kwon Koo
BACKGROUND: Invasive physiologic indices, such as fractional flow reserve (FFR) or instantaneous wave-free ratio (iFR), are used in clinical practice. We sought to evaluate the physiological mechanism of discordance between iFR and FFR using (13)N-ammonia positron emission tomography (PET)-derived quantitative parameters. METHODS: Data from 113 patients, who underwent both (13)N-ammonia PET and invasive FFR and iFR measurement, were analyzed. Coronary circulatory indices, such as myocardial blood flow (MBF), coronary flow reserve (CFR), microvascular resistance, and trans-stenosis resistance were compared between patients with discordant results (low FFR despite high iFR) and those with concordant abnormal results (low FFR and low iFR), using cut-off values of FFR≤0...
June 2, 2017: International Journal of Cardiology
https://www.readbyqxmd.com/read/28598182/masticatory-parameters-of-children-with-and-without-clinically-diagnosed-caries-in-permanent-dentition
#4
M S Kaya, S Akyuz, B Guclu, D Diracoglu, A Yarat
AIM: Mastication turns food into a bolus and prepares it for chemical digestion. Any condition affecting tooth structure and position may have an impact on mastication. The aim of this study is to compare masticatory performance (MP) and maximum bite force (MBF) between children with and without clinically visible caries in permanent first molars. MATERIALS AND METHODS: The study was conducted with 50 children in good general condition aged 12-14 years (25 girls, 25 boys) with no orthodontic/skeletal anomalies and no missing teeth due to dental trauma or extraction...
June 2017: European Journal of Paediatric Dentistry: Official Journal of European Academy of Paediatric Dentistry
https://www.readbyqxmd.com/read/28594441/rapid-computation-of-single-pet-scan-rest-stress-myocardial-blood-flow-parametric-images-by-table-look-up
#5
Nicolas J Guehl, Marc D Normandin, Dustin W Wooten, Guy Rozen, Jeremy Ruskin, Timothy M Shoup, Jonghye Woo, Leon M Ptaszek, Georges El Fakhri, Nathaniel M Alpert
PURPOSE: We have recently reported a method for measuring rest-stress myocardial blood flow (MBF) using a single, relatively short, PET scan session. The method requires two IV tracer injections, one to initiate rest imaging and one at peak stress. We previously validated absolute flow quantitation in ml/min/cc for standard bull's eye, segmental analysis. In this work, we extend the method for fast computation of rest-stress MBF parametric images. METHODS: We provide an analytic solution to the single-scan rest-stress flow model which is then solved using a two-dimensional table lookup method (LM)...
June 8, 2017: Medical Physics
https://www.readbyqxmd.com/read/28593557/assessment-of-myocardial-blood-flow-and-coronary-flow-reserve-with-positron-emission-tomography-in-ischemic-heart-disease-current-state-and-future-directions
#6
REVIEW
Firas Al Badarin, Ahmed Aljizeeri, Fatimah Almasoudi, Mouaz H Al-Mallah
Positron emission tomography (PET) is a versatile imaging technology that allows assessment of myocardial perfusion, both at a spatially relative scale and also in absolute terms, thereby enabling noninvasive evaluation of myocardial blood flow (MBF) and coronary flow reserve (CFR). Assessment of MBF using FDA-approved PET isotopes, such as (82)Rb and (13)N-ammonia, has been well validated, and several software packages are currently available, thereby allowing for MBF evaluation to be incorporated into routine workflow in contemporary nuclear laboratories...
June 7, 2017: Heart Failure Reviews
https://www.readbyqxmd.com/read/28585219/pet-ct-scanning-with-3d-acquisition-is-feasible-for-quantifying-myocardial-blood-flow-when-diagnosing-coronary-artery-disease
#7
Osamu Manabe, Masanao Naya, Tadao Aikawa, Masahiko Obara, Keiichi Magota, Markus Kroenke, Noriko Oyama-Manabe, Kenji Hirata, Daiki Shinyama, Chietsugu Katoh, Nagara Tamaki
BACKGROUND: The quantification of myocardial blood flow (MBF) and coronary flow reserve (CFR) are useful approaches for evaluating the functional severity of coronary artery disease (CAD). (15)O-water positron emission tomography (PET) is considered the gold standard method for MBF quantification. However, MBF measurements in (15)O-water PET with three-dimensional (3D) data acquisition, attenuation correction using computed tomography (CT), and time of flight have not been investigated in detail or validated...
December 2017: EJNMMI Research
https://www.readbyqxmd.com/read/28577226/pet-measurements-of-myocardial-blood-flow-post-myocardial-infarction-relationship-to-invasive-and-cardiac-magnetic-resonance-studies-and-potential-clinical-applications
#8
Henry Gewirtz
This review focuses on clinical studies concerning assessment of coronary microvascular and conduit vessel function primarily in the context of acute and sub acute myocardial infarction (MI). The ability of quantitative PET measurements of myocardial blood flow (MBF) to delineate underlying pathophysiology and assist in clinical decision making in this setting is discussed. Likewise, considered are physiological metrics fractional flow reserve, coronary flow reserve, index of microvascular resistance (FFR, CFR, IMR) obtained from invasive studies performed in the cardiac catheterization laboratory, typically at the time of PCI for MI...
June 2, 2017: Journal of Nuclear Cardiology: Official Publication of the American Society of Nuclear Cardiology
https://www.readbyqxmd.com/read/28540215/myocardial-flow-reserve-mfr-with-positron-emission-tomography-pet-computed-tomography-ct-clinical-impact-in-diagnosis-and-prognosis
#9
REVIEW
Maria Cecilia Ziadi
In recent years, radionuclide myocardial perfusion imaging (MPI) using positron emission tomography/computed tomography (PET/CT) has emerged as a robust tool for the diagnosis, risk stratification and management of patients with known or established coronary artery disease (CAD). Cardiac PET/CT imaging affords key advantages compared to single photon emission computed tomography (SPECT) that encompass: (I) improved diagnostic accuracy; (II) decreased radiation exposure due to the utilization of short-lived radiopharmaceuticals, and importantly; (III) the ability to quantify noninvasively myocardial blood flow (MBF) in absolute terms, that is in ml per minute per gram of tissue...
April 2017: Cardiovascular Diagnosis and Therapy
https://www.readbyqxmd.com/read/28540214/coronary-microvascular-dysfunction-in-women-with-nonobstructive-ischemic-heart-disease-as-assessed-by-positron-emission-tomography
#10
REVIEW
Roxana Campisi, Fernando D Marengo
Traditional approaches for risk assessment of ischemic heart disease (IHD) are based on the physiological consequences of an epicardial coronary stenosis. Of note, normal coronary arteries or nonobstructive coronary artery disease (CAD) is a common finding in women with signs and symptoms of ischemia. Therefore, assessment of risk based on a coronary stenosis approach may fail in women. Positron emission tomography (PET) quantifies absolute myocardial blood flow (MBF) which may help to elucidate other mechanisms involved such as endothelial dysfunction and alterations in the smooth muscle cell relaxation responsible for IHD in women...
April 2017: Cardiovascular Diagnosis and Therapy
https://www.readbyqxmd.com/read/28536897/validation-of-myocardial-perfusion-quantification-by-dynamic-ct-in-an-ex-vivo-porcine-heart-model
#11
Gert Jan Pelgrim, Marco Das, Sjoerd van Tuijl, Marly van Assen, Frits W Prinzen, Marco Stijnen, Matthijs Oudkerk, Joachim E Wildberger, Rozemarijn Vliegenthart
To test the accuracy of quantification of myocardial perfusion imaging (MPI) using computed tomography (CT) in ex-vivo porcine models. Five isolated porcine hearts were perfused according to Langendorff. Hearts were perfused using retrograde flow through the aorta and blood flow, blood pressure and heart rate were monitored throughout the experiment. An inflatable cuff was placed around the circumflex (Cx) artery to create stenosis grades which were monitored using a pressure wire, analysing perfusion at several fractional flow reserve values of 1...
May 23, 2017: International Journal of Cardiovascular Imaging
https://www.readbyqxmd.com/read/28523283/variable-temporal-sampling-and-tube-current-modulation-for-myocardial-blood-flow-estimation-from-dose-reduced-dynamic-computed-tomography
#12
Dimple Modgil, Michael D Bindschadler, Adam M Alessio, Patrick J La Rivière
Quantification of myocardial blood flow (MBF) can aid in the diagnosis and treatment of coronary artery disease. However, there are no widely accepted clinical methods for estimating MBF. Dynamic cardiac perfusion computed tomography (CT) holds the promise of providing a quick and easy method to measure MBF quantitatively. However, the need for repeated scans can potentially result in a high patient radiation dose, limiting the clinical acceptance of this approach. In our previous work, we explored techniques to reduce the patient dose by either uniformly reducing the tube current or by uniformly reducing the number of temporal frames in the dynamic CT sequence...
April 2017: Journal of Medical Imaging
https://www.readbyqxmd.com/read/28516230/diverse-roles-of-dpb2-the-non-catalytic-subunit-of-dna-polymerase-%C3%AE%C2%B5
#13
REVIEW
Michał Dmowski, Iwona J Fijałkowska
Timely progression of living cells through the cell cycle is precisely regulated. This involves a series of phosphorylation events which are regulated by various cyclins, activated in coordination with the cell cycle progression. Phosphorylated proteins govern cell growth, division as well as duplication of the genetic material and transcriptional activation of genes involved in these processes. A subset of these tightly regulated genes, which depend on the MBF transcription factor and are mainly involved in DNA replication and cell division, is transiently activated at the transition from G1 to S phase...
May 17, 2017: Current Genetics
https://www.readbyqxmd.com/read/28514327/postoperative-assessment-of-myocardial-function-and-microcirculation-in-patients-with-acute-coronary-syndrome-by-myocardial-contrast-echocardiography
#14
Li Jiang, Hong Yao, Zhao-Guang Liang
BACKGROUND Postoperative myocardial function and microcirculation of acute coronary syndrome (ACS) was assessed by myocardial contrast echocardiography (MCE). MATERIAL AND METHODS Eighty-nine ACS patients treated with percutaneous coronary intervention (PCI) were detected by MCE and two-dimensional ultrasonography before and a month later after PCI respectively. Their myocardial perfusion was evaluated by myocardial contrast score (MSC) and contrast score index (CSI); cross-sectional area of microvessel (A), average myocardial microvascular impairment (β), and myocardial blood flow (MBF) were analyzed by cardiac ultrasound quantitative analysis (CUSQ), and fractional flow reserve (FFR) change was observed...
May 17, 2017: Medical Science Monitor: International Medical Journal of Experimental and Clinical Research
https://www.readbyqxmd.com/read/28508271/optimization-of-temporal-sampling-for-82-rubidium-pet-myocardial-blood-flow-quantification
#15
Benjamin C Lee, Jonathan B Moody, Richard L Weinberg, James R Corbett, Edward P Ficaro, Venkatesh L Murthy
BACKGROUND: Suboptimal temporal sampling of left ventricular (LV) blood pool and tissue time-activity curves (TACs) may introduce bias and increased variability in estimates of myocardial blood flow (MBF) and flow reserve (MFR) from dynamic PET myocardial perfusion images. We aimed to optimize temporal sampling for estimation of MBF and MFR. METHODS: Twenty-four normal volunteers and 32 patients underwent dynamic stress/rest rubidium-82 chloride ((82)Rb) PET imaging...
May 15, 2017: Journal of Nuclear Cardiology: Official Publication of the American Society of Nuclear Cardiology
https://www.readbyqxmd.com/read/28505153/gene-duplication-and-co-evolution-of-g1-s-transcription-factor-specificity-in-fungi-are-essential-for-optimizing-cell-fitness
#16
Adi Hendler, Edgar M Medina, Anastasiya Kishkevich, Mehtap Abu-Qarn, Steffi Klier, Nicolas E Buchler, Robertus A M de Bruin, Amir Aharoni
Transcriptional regulatory networks play a central role in optimizing cell survival. How DNA binding domains and cis-regulatory DNA binding sequences have co-evolved to allow the expansion of transcriptional networks and how this contributes to cellular fitness remains unclear. Here we experimentally explore how the complex G1/S transcriptional network evolved in the budding yeast Saccharomyces cerevisiae by examining different chimeric transcription factor (TF) complexes. Over 200 G1/S genes are regulated by either one of the two TF complexes, SBF and MBF, which bind to specific DNA binding sequences, SCB and MCB, respectively...
May 2017: PLoS Genetics
https://www.readbyqxmd.com/read/28504545/detection-of-hemodynamically-significant-coronary-artery-stenosis-with-ct-enhancement-ratio-a-validation-study-in-a-porcine-model
#17
Jun Chen, Yang Pu, Zhang Zhang, Xuefang Yu, Zhengwen Yang
OBJECTIVE: Although numerous techniques that are based on CT number analysis have been proposed, the assessment of hemodynamically significant coronary artery stenosis remains a great challenge. The purpose of this study is to validate use of the CT enhancement ratio in the detection of hemodynamically significant coronary artery stenosis in a porcine model. MATERIALS AND METHODS: Experiments involving eight closed-chest swine were performed. A balloon catheter was placed into the left anterior descending coronary artery to simulate different degrees of luminal stenosis...
May 15, 2017: AJR. American Journal of Roentgenology
https://www.readbyqxmd.com/read/28501269/peak-enhancement-ratio-of-myocardium-to-aorta-for-identification-of-myocardial-ischemia-using-dynamic-myocardial-computed-tomography-perfusion-imaging
#18
Yuki Tanabe, Teruhito Kido, Akira Kurata, Takahiro Yokoi, Naoki Fukuyama, Teruyoshi Uetani, Hikaru Nishiyama, Naoto Kawaguchi, Enver Tahir, Masao Miyagawa, Teruhito Mochizuki
BACKGROUND: This study aimed to evaluate the feasibility of peak enhancement (PE) ratio of myocardium to aorta (PER) derived from stress dynamic computed tomography myocardial perfusion imaging (CTP) for the detection of myocardial ischemia assessed by magnetic resonance (MR) imaging. METHODS: Forty-four patients who underwent stress dynamic CTP and MR imaging were retrospectively evaluated. From the time-attenuation curve, myocardial PE, PER, and myocardial blood flow (MBF) were calculated on a segment-based analysis...
May 10, 2017: Journal of Cardiology
https://www.readbyqxmd.com/read/28465300/randomized-trial-comparing-the-effects-of-ticagrelor-versus-clopidogrel-on-myocardial-perfusion-in-patients-with-coronary-artery-disease
#19
Matthieu Pelletier-Galarneau, Chad R R N Hunter, Kathryn J Ascah, Rob S B Beanlands, Girish Dwivedi, Robert A deKemp, Benjamin J W Chow, Terrence D Ruddy
BACKGROUND: Ticagrelor is a P2Y12 receptor inhibitor used in acute coronary syndromes to reduce platelet activity and to decrease thrombus formation. Ticagrelor is associated with a reduction in mortality incremental to that observed with clopidogrel, potentially related to its non-antiplatelet effects. Evidence from animal models indicates that ticagrelor potentiates adenosine-induced myocardial blood flow (MBF) increases. We investigated MBF at rest and during adenosine-induced hyperemia in patients with stable coronary artery disease treated with ticagrelor versus clopidogrel...
May 2, 2017: Journal of the American Heart Association
https://www.readbyqxmd.com/read/28459157/infliximab-alleviates-the-mortality-mesenteric-hypoperfusion-aortic-dysfunction-and-multiple-organ-damage-in-septic-rats
#20
Erdem Kamil Ozer, Mustafa Tugrul Goktas, Ibrahim Kilinc, Aysun Toker, Hulagu Bariskaner, Ceyhan Ugurluoglu, Alper Bektas Iskit
Tumor necrosis factor-alpha (TNF-α) is a pivotal mediator that triggers inflammatory process, oxidative stress and multiple organ injury in sepsis. We investigated the effects of infliximab on survival, mesenteric artery blood flow (MBF), vascular reactivity, oxidative and inflammatory injuries in cecal ligation and puncture (CLP) induced sepsis. Wistar rats were divided into Sham, CLP, Sham+infliximab, CLP+infliximab subgroups. 24 hours before the operations rats were injected intraperitoneally with infliximab (7 mg/kg) or vehicle (saline; 1 mL/kg)...
April 29, 2017: Canadian Journal of Physiology and Pharmacology
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