Echocardiography

The book "Echocardiography - In Specific Diseases" brings together contributions from well- known researchers from around the world, some of them specialized in imaging science in their clinical orientation, but also representatives from academic medical centers. Each chapter is structured and written to be accessible to those with a basic knowledge of echocardiography but also to be stimulating and informative to experts and researchers in the field of echocardiography. This book is primarily aimed at cardiology fellows during their basic echocardiography rotation, fellows of internal medicine, radiology and emergency medicine, but also experts in echocardiography. During the past few decades technological advancements in echocardiography have been developing rapidly, leading to improved echocardiographic imaging using new techniques. The authors of this book tried to explain the role of echocardiography in several special pathologies, which the readers may find in different chapters of the book

Flavonoid protection of cardiac cells against ischemia-reperfusion injury

Myocardial ischemia-reperfusion injury occurs following the majority of cardiac events including myocardial stenosis and heart surgeries. As reactive oxygen species are one of the major contributors to ischemia-reperfusion injury, strategies to prevent their effects may be directed towards enhancing the antioxidant capacity of cells. Polyphenols, and in a more specific category, flavonoids are strong antioxidants, while possessing other biological activities such as anti-apoptotic, anti-inflammatory, and vasodilatory effects. I hypothesized that flavonoids are able to reduce ischemia-reperfusion-induced cell death through multiple mechanisms including reduction of oxidative stress and induction of cellular antioxidant enzymes. The hypothesis was tested in in vitro and in vivo phases.In the first phase of the studies, rat embryonic ventricular H9c2 cells were treated with various concentrations of polyphenols with or without ascorbate for 1-3 days before induction of ischemia and reperfusion. Ischemia was induced by exposure of the cells to a non-glucose containing solution bubbled with nitrogen, and reperfusion by returning the regular medium containing the corresponding polyphenols and/or ascorbate. Cell viability measurements using the MTT assay or counting acridine orange-stained cells showed that the best protection against cell death was given by catechin (44-58 %), epigallocatechin gallate (48%), proanthocyanidins (44%), and ascorbic acid (57-92%). A low concentration (10 µM) of catechin was more effective with a long-term (2 days) incubation time (64%), while a higher concentration (50 µM) could exert benefit even after 1 h pre-treatment (98%). Quercetin, resveratrol, cyanidin, and delphinidin displayed almost no protection. In the second part of the in vitro study, H9c2 cells were treated with 350 to 450 µM tert-butyl hydroperoxide for 24 h after pre-incubation with various concentrations of polyphenols with or without ascorbate for either short (1 h) or prolonged (3 days) periods. Unlike in the ischemia-reperfusion experiments, 3 days pre-treatment with polyphenols did not protect and often caused cytotoxicity. In short-term (1 h) pre-treatments, the best protection was obtained with 50 µM quercetin (95%), 50 µM epigallocatechin gallate (66%), and 100 µM catechin (28%). Pre-treatment with ascorbic acid (100 µM) with or without polyphenols did not improve cell survival except in one case where it enhanced cytoprotection by epigallocatechin gallate.The second phase of the studies was performed with isolated rat hearts. Rats were fed diets containing broccoli sprouts (2%), saskatoon berries (5%), or green tea extract (0.25%) for 10 days before induction of global ischemia for 20 min and reperfusion for 2 h. Broccoli sprouts decreased cell death in ischemic-reperfused hearts as assessed by caspase-3 activity (86%) and DNA fragmentation (78 %), attenuated oxidative damage as detected by lower thiobarbituric acid reactive substances (TBARS) (116%) and preserved aconitase activity (82%). Green tea extract prevented apoptosis in hearts as detected by caspase-3 activity (85%), but did not inhibit DNA fragmentation. Berries showed lower TBARS (73%). None of the feedings significantly prevented necrosis as evaluated by the release of lactate dehydrogenase into the coronary effluents, improved coronary flow, or increased heart glutathione.Green tea extract was the only intervention capable of preserving the activity of glutamate cysteine ligase (78%) and quinone reductase (147%) in hearts. The sprouts group was the only group which induced these same enzymes in liver (40 and 44 %, respectively), as it was the only intervention which elevated total liver glutathione (12%). None of the interventions changed heme oxygenase-1 protein levels. Assessment of total polyphenol content revealed that broccoli sprouts had the lowest and green tea extract had the highest amount of polyphenols among the three plant materials, suggesting that the protection exhibited by broccoli sprouts was unlikely to be due to the polyphenols. In conclusion, flavonoids and flavonoid-rich foods can strengthen the cellular ability to fight against oxidative stress. A part of this effect could be due to their direct antioxidant activity, while in prolonged applications they may also activate cellular pathways to promote endogenous antioxidant defences of cells. Application of low doses of flavonoids and consumption of flavonoid-rich plants in long-term ensures their effectiveness while avoiding possible toxicity. However, plants such as broccoli sprouts may have other chemical ingredients bearing biological properties which may help cells to survive states of oxidative stress

Heart rate and blood pressure variability : association with white matter lesions and cognitive function following stroke

Dementia presents a significant health care burden. Older post-stroke patients suffer high rates of dementia. Subcortical ischaemia may be an important mechanism of cognitive decline, particularly in older patients with cerebrovascular disease. It is hypothesised that abnormal heart rate and blood pressure variability will increase white matter lesion volume through hypoperfusion. This may lead to a subcortical pattern of cognitive decline characterised for example by deficits in attention and concentration. Stroke patients aged > 75 years and free of dementia had a series of cardiovascular autonomic, brain imaging and neuropsychometric investigations performed more than three months following incident stroke. Annual neuropsychometric assessment included CAMCOG score and measures of reaction time and concentration using a series of visual and numerical tasks presented on computer (Cognitive Drug Research Assessment System). Autonomic function is impaired in older stroke patients in the long term after stroke. These deficits are weakly associated with cross-sectional measures of sub-cortical performance but do not predict subsequent decline in cognitive function. Twenty-four hour blood pressure variability is associated with white matter disease and excessive nocturnal dipping is associated with impaired cognitive function. Again blood pressure variability does not help predict subsequent change in white matter lesion burden or cognitive function. This study provides limited support for the hypoperfusion theory of post-stroke cognitive impairment. However it does not indicate a role for heart rate and blood pressure variability in the mechanism of increasing white matter disease or decline in cognition in the two years following stroke.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Primary Angioplasty

Medicine; Cardiolog

Brain Injury

The present two volume book "Brain Injury" is distinctive in its presentation and includes a wealth of updated information on many aspects in the field of brain injury. The Book is devoted to the pathogenesis of brain injury, concepts in cerebral blood flow and metabolism, investigative approaches and monitoring of brain injured, different protective mechanisms and recovery and management approach to these individuals, functional and endocrine aspects of brain injuries, approaches to rehabilitation of brain injured and preventive aspects of traumatic brain injuries. The collective contribution from experts in brain injury research area would be successfully conveyed to the readers and readers will find this book to be a valuable guide to further develop their understanding about brain injury