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Tumor microenvironment (TME) has become an important target for studying cancer progression in recent times. Disorientation of the collagen fiber network is a common phenomenon during cancer invasion process. In this study, using in vitro myoma organotypic model with invading melanoma and oral tongue carcinoma cell lines, we identified the influence of the cancer cells in the TME by Fourier-transform infrared (FTIR) imaging. We found major changes in the relative intensities of the collagen bands. Principal component analysis was performed to explore feasibility of classification between spectra extracted from different regions. A submolecular justification of the classification model was sought using a curve fitting analysis. Our preliminary results suggest that the features present in the amide and collagen triplet regions could serve as spectral markers for cancer-induced modifications in the TME. We suggest that FTIR method, combined with myoma invasion model, could be used to analyze various tumor cells interactions with TME during invasion processes. [ABSTRACT FROM AUTHOR]

Objectives: To test the image quality and feasibility of a sequential low radiation dose protocol for hybrid cardiac PET/CT angiography (CTA). Background: Multidetector computed tomography (MDCT) is a non-invasive method for coronary angiography. The negative predictive value of MDCT is high but perfusion imaging has a role in detecting functional significance of coronary lesions. This has encouraged combining these techniques. However, radiation dose is of concern. We report our first experiences with a low dose sequential CTA mode applicable to hybrid imaging. Methods: In the first phase, 10 consecutive cardiac MDCT angiographies were performed with spiral acquisition and compared in terms of image quality and dose with the following 10 patients performed with a new sequential mode. In the second phase, feasibility and radiation dose of a combined 15O-water rest-stress PET perfusion/sequential CTA protocol were assessed in another group of 61 consecutive patients. Results: Mean effective radiation dose was 60% lower in the sequential group than in the spiral group (19·3 versus 7·6 mSv, P<0·001). In the second phase, the new sequential hybrid protocol proved possible in 87% of the patients given the preconditions determined by the manufacturer. Mean effective dose of the CT acquisition was 7·6 mSv and total dose from the PET/CTA hybrid study 9·5 mSv. Conclusion: Low dose PET/CT allows cardiac hybrid studies with <10 mSv. The protocol can be applied to almost nine out of 10 patients with CT image quality comparable to spiral acquisition. [ABSTRACT FROM AUTHOR]

Background: The relationship between minute ventilation and the rate of CO2 elimination (VE/VCO2 slope) is associated with mortality in patients with congestive heart failure (CHF). The VE/VCO2 slope > or =34 denotes a poor prognosis and has been proposed to reflect abnormalities in pulmonary perfusion. Aims: To study whether increased VE/VCO2 slope is associated with elevated right ventricular (RV) oxidative metabolism relative to the left ventricle (LV). Methods: 21 patients with stable NYHA II-III CHF underwent symptom limited cardiopulmonary exercise testing. Dynamic [(11)C]acetate positron emission tomography (PET) was used to measure oxidative metabolism (k(mono)) of the LV and RV. Corrected RV oxidative metabolism (RVOx) was calculated as RV/LV k(mono) ratio. Results: Peak VO2 was 16.2+/-4.1 ml/min/kg and the VE/VCO2 slope was 33.4+/-6.1. LV and RV k(mono) were 0.046+/-0.009 and 0.037+/-0.007 min(-1), respectively, with a RVOx of 0.83+/-0.17. There was a good correlation between RVOx and the VE/VCO2 slope (r=0.61, p=0.0034). RVOx was 0.77+/-0.16 in patients with a VE/VCO2 slope <34 and 0.93+/-0.16 in patients with VE/VCO2 slope > or =34 (p=0.047). Conclusion: RVOx correlates with VE/VCO2 slope in CHF patients. This supports the hypothesis that pulmonary vascular resistance is a determinant of the VE/VCO2 slope. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to determine the effect of exercise training on myocardial oxidative metabolism and efficiency in patients with idiopathic dilated cardiomyopathy (DCM) and mild heart failure (HF).Background: Exercise training is known to improve exercise tolerance and quality of life in patients with chronic HF. However, little is known about how exercise training may influence myocardial energetics.Methods: Twenty clinically stable patients with DCM (New York Heart Association classes I through III) were prospectively separated into a training group (five-month training program; n = 9) and a non-trained control group (n = 11). Oxidative metabolism in both the right and left ventricles (RV and LV) was measured using [(11)C]acetate and positron emission tomography. Myocardial work power was measured using echocardiography. Myocardial efficiency for forward work was calculated as myocardial work power per mass/LV oxidative metabolism.Results: Significant improvements were noted in exercise capacity (VO(2)) and ejection fraction in the training group, whereas no changes were observed in the non-trained group. Exercise training reduced both RV and LV oxidative metabolism and elicited a significant increase in LV forward work efficiency, although no significant changes were observed in the non-trained group.Conclusions: Exercise training improves exercise tolerance and LV function. This is accompanied by a decrease in biventricular oxidative metabolism and enhanced forward work efficiency. Therefore, exercise training elicits an energetically favorable improvement in myocardial function and exercise tolerance in patients with DCM. [ABSTRACT FROM AUTHOR]

The integrative mechanisms of autonomic dysfunction in congestive heart failure (CHF) remain poorly understood. We sought to study cardiac retention of [11C]hydroxyephedrine (HED), a specific tracer for sympathetic presynaptic innervation, and its functional correlates in CHF. Thirty patients with mild to moderate heart failure underwent resting cardiac HED positron emission tomography imaging, spectrum analysis testing of systolic pressure and heart rate variability in the resting supine and 70 degrees head-up tilt positions, and testing of baroreflex sensitivity. Compared with control subjects, global myocardial HED retention index was reduced by 30% (p <0.01) in patients with CHF. The HED retention index did not correlate significantly with heart rate variability. However, it correlated with baroreflex sensitivity at rest (r = 0.43, p = 0.05) and with systolic pressure low-frequency (0.03 to 0.15 Hz) variability at head-up tilt (r = 0.76, p <0.01), as well as with low-frequency systolic pressure variability response from baseline to tilt (r = 0.75, p <0.01). We conclude that cardiac HED retention is reduced in patients with CHF. This correlates with blunted vascular sympathetic effector responses during posture-induced reflex activation and baroreflex control of heart rate, suggesting an interdependence between cardiac presynaptic innervation abnormalities and neural mechanisms important to blood pressure maintenance in CHF. [ABSTRACT FROM AUTHOR]

An abstract of the study "Cardiac Function and Efficiency are Dependent on FFA Availability in Patients With Idiopathic Dilated Cardiomyopathy," by H. Tuunanen and colleagues is presented.

An abstract of the study "The effect of FFA betaoxidation inhibution on myocardial metabolism and function in patients with idiopathic dilated cardiomyopathy," by H. Tuunanen and colleagues, is presented.