Effect of eccentric training on mitochondrial function and oxidative stress in the skeletal muscle of rats.

The objective of the present study was to investigate the effects of eccentric training on the activity of mitochondrial respiratory chain enzymes, oxidative stress, muscle damage, and inflammation of skeletal muscle. Eighteen male mice (CF1) weighing 30-35 g were randomly divided into 3 groups (N = 6): untrained, trained eccentric running (16°; TER), and trained running (0°) (TR), and were submitted to an 8-week training program. TER increased muscle oxidative capacity (succinate dehydrogenase and complexes I and II) in a manner similar to TR, and TER did not decrease oxidative damage (xylenol and creatine phosphate) but increased antioxidant enzyme activity (superoxide dismutase and catalase) similar to TR. Muscle damage (creatine kinase) and inflammation (myeloperoxidase) were not reduced by TER. In conclusion, we suggest that TER improves mitochondrial function but does not reduce oxidative stress, muscle damage, or inflammation induced by eccentric contractions.

Effect of eccentric training on mitochondrial function and oxidative stress in the skeletal muscle of rats

The objective of the present study was to investigate the effects of eccentric training on the activity of mitochondrial respiratory chain enzymes, oxidative stress, muscle damage, and inflammation of skeletal muscle. Eighteen male mice (CF1) weighing 30-35 g were randomly divided into 3 groups (N = 6): untrained, trained eccentric running (16°; TER), and trained running (0°) (TR), and were submitted to an 8-week training program. TER increased muscle oxidative capacity (succinate dehydrogenase and complexes I and II) in a manner similar to TR, and TER did not decrease oxidative damage (xylenol and creatine phosphate) but increased antioxidant enzyme activity (superoxide dismutase and catalase) similar to TR. Muscle damage (creatine kinase) and inflammation (myeloperoxidase) were not reduced by TER. In conclusion, we suggest that TER improves mitochondrial function but does not reduce oxidative stress, muscle damage, or inflammation induced by eccentric contractions.

Effect of physical training on the adipose tissue of diet-induced obesity mice: interaction between reactive oxygen species and lipolysis.

It is well known that high-fat diets (HFDs) induce obesity and result in an increase in oxidative stress in adipose tissue, which leads to an impairment of fat mobilization by a downregulation of the lipases, such as hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL). On the other hand, exercise training leads to a reduction in adipose tissue and an improvement of antioxidant status and the lipolytic pathway. Our aim was to examine the influence of exercise and moderate intensity training on oxidative stress parameters and the relationship between the proteins involved in the lipolysis of animals subjected to a high-fat fed diet. Twenty-four mice were used and divided into 4 groups (n=6): standard diet (SD); standard diet plus exercise (SD+Ex); high-fat diet (HFD); and high-fat diet plus exercise (HFD+Ex). The animals received HFD for 90 days and submitted to a daily training protocol in swinging. The animals were euthanized 48 h after the last session of exercise. White adipose tissue epididymal fat was excised for the measurement of oxidative stress parameters and protein levels of lipolytic enzymes by Western blotting. The results show an increase in body weight after 90 days of HFD, and exercise training prevented great gain. In adipose tissue, lipid peroxidation and protein carbonylation increased after HFD and decreased significantly after exercise training. The protein level of CGI-58 was reduced, and FAS was increased in the HFD than in SD, whereas ATGL exhibited an increase (p<0.05) in HFD than in SD. The exercise plays a significant role in reducing oxidative damage, along with the regulation of proteins that are involved in the lipolysis of animals exposed to HFD.

The role of intravascular ultrasound imaging in vascular brachytherapy.

Intracoronary brachytherapy has recently emerged as a new therapy to prevent restenosis. Initial experimental work was achieved in animal models and the results were assessed by histomorphometry. Initial clinical trials used angiography to guide dosimetry and to assess efficacy. Intravascular ultrasound (IVUS) permits tomographic examination of the vessel wall, elucidating the true morphology of the lumen and transmural components, which cannot be investigated on the lumenogram obtained by angiography. This paper reviews the use of IVUS in the clinical studies of brachytherapy conducted to date. IVUS allows clinicians to make a thorough assessment of the remodeling of the vessel and appears to have a major role to play in facilitating understanding of the underlying mechanisms of action in this emerging field. The authors propose that state-of-the-art IVUS techniques should be employed to further knowledge of the mechanisms of action of brachytherapy in atherosclerotic human coronary arteries.

Temporal averaging for quantification of lumen dimensions in intravascular ultrasound images.

Quantitative analysis of arterial dimensions from high frequency intravascular ultrasound images (30 MHz) may be hampered by strong blood scattering. Replacement of blood by saline is one method to provide a clear view of the arterial lumen; another method is that of temporal averaging of successive ultrasound images. The accuracy of this latter method was tested by comparing the lumen area measurements on the temporal-averaged image, with the data of the same cross-section obtained from the single-frame and saline-filled images. The mean lumen area measured on the temporal-averaged images was similar to that measured on the single-frame images (mean difference: -0.02 +2- 1.16 mm2; p = ns). The mean lumen area of the saline-filled images was 8% larger than the values obtained from the temporal-averaged and single-frame images (mean difference: -1.14 +/- 0.85 mm2, p < 0.05), probably due to the difference in sound velocity between saline and blood. Intraobserver variation in the averaging method were 2.4 times smaller than the measurements of the single-frame images and close to the data obtained by saline injection (variation coefficient: single-frame: 8.8%; temporal-averaged: 3.6%; saline-filled: 2.9%). It is concluded that analysis from temporal-averaged images is more efficient, enabling accurate and reproducible measurement of the luminal dimensions from images containing blood scattering echoes. This technique is suitable to replace the laborious saline injection method and facilitates off-line quantitative analysis.

Extrinsic compression of the superficial femoral artery at the adductor canal: evaluation with intravascular sonography.

Balloon angioplasty of the superficial femoral artery was performed in 15 consecutive patients with obstructive atherosclerotic disease near the adductor hiatus. After angioplasty, extrinsic compression of the femoral artery at the adductor hiatus was shown on intravascular sonograms in five patients (33%). In retrospect, this inward deformation of the arterial wall was thought to be present in only one case before angioplasty. After angioplasty, intravascular sonography was used successfully to differentiate between residual stenosis due to residual plaque and that due to extrinsic compression of the wall of the femoral artery near the adductor hiatus. We conclude that intravascular sonography may be a useful adjunct to angiography for determining the cause of residual stenosis.

Intravascular ultrasonic assessment of lumen geometry and distensibility of the angiographically normal artery: a correlation with quantitative angiography.

The feasibility of assessing lumen diameter and area using a 30-MHz mechanically driven ultrasound imaging device was evaluated in vitro in phantoms and in vivo in eight human arteries (six iliac, two brachial). Ultrasound data were compared to angiographic data derived from the cardiovascular angiographic analysis system. In addition, the change of lumen area in a given cardiac cycle was determined in each patient. A close relation between ultrasound and angiography was observed in the phantom studies. In the first three patients there was disagreement; ultrasound images showed larger values compared to the angiographically derived values. Disagreement was related to the use of nominal measurements of the sheath supplied by the manufacturer as calibration. Data on the five other patients showed a close relation between the values derived with ultrasound and angiography. The arterial lumen area revealed a 5% +/- 2% change during one cardiac cycle. The intra- and interobserver variability test showed good correlation for the ultrasound study. This study demonstrates that intravascular ultrasound is an accurate and reproducible technique to measure vascular diameter, lumen area, and arterial wall distensibility in vivo.

Oesophageal echocardiography.

The diagnostic value of oesophageal echocardiography is most striking in patients in whom precordial studies are of inadequate quality or fail to establish a definitive diagnosis. Oesophageal studies have excellent image quality, can be completed within 10 minutes without complications and, in most instances, enables the clinical question to be answered. In 50 patients referred for suspected thoracic aorta pathology, oesophageal echocardiography correctly excluded or diagnosed the type of aortic dissection, aortic aneurysm or the site of coarctation. Of 35 patients referred with suspected infective endocarditis, oesophageal echocardiography revealed complications in 18 patients, including vegetation, mycotic aneurysm, abscess or chordal rupture. Oesophageal echocardiography is extremely helpful to visualize intracardiac mass lesions. In 27 patients with a history of systemic or pulmonary embolism, the technique confirmed the presence, size and position of a mass lesion in 11 patients. Oesophageal color Doppler flow imaging further expands the diagnostic capabilities, particularly in patients with mitral valve prosthesis. Our experience indicates that oesophageal echocardiography significantly extends the diagnostic potential of echocardiography. Detailed knowledge of cardiothoracic anatomy and its pathologic sequelae is, however, a prerequisite for the efficient and safe application of this method.

On the aliasing problem in pulsed Doppler cardiac studies.

In pulsed Doppler echocardiography the maximum measurable velocity is limited due to the aliasing phenomenon. Particularly in cardiac echo studies in adults, aliasing may occur frequently. The principle of and the parameters that influence aliasing will be explained. The importance of aliasing is demonstrated in examples of tricuspid, mitral, and aortic Doppler echocardiographic studies in adults. Ways to reduce or avoid aliasing are presented.

The ultrasound cardioscope: a hand-held scanner for real-time cardiac imaging.

A miniaturized hand-held ultrasound scanner that permits two-dimensional echocardiography is described. The device has been routinely used in our emergency department, coronary care unit, wards, and outpatient department. The device has advantages in situations where rapid decisions are demanded of the expert echocardiographer. It permits improved bedside analysis of patients with puzzling cardiac conditions. An important feature is that the instrument can be used as a substitute for cardiac fluoroscopy in office practice. Tests performed in 100 consecutive patients have demonstrated that reasonable semiquantitative estimation of the sizes of left-side heart structures is possible. This new-generation instrument can make diagnostic ultrasound more readily available in emergency situations and should have considerable influence on the use of cardiac ultrasound for bedside diagnosis. It will undoubtedly affect future developments in automatic, portable, and special dedicated ultrasound equipment.