52 research outputs found

    Investigating the role of the YEARextracellular calcium-sensing receptor(CaSR) in vascular pathophysiology using a novel mouse model of selective ablation of CaSR from mouse vascular smooth muscle cells

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    The extracellular calcium-sensing receptor (CaSR) is a G-protein coupled receptor central to systemic Ca2+ homeostasis in mammals. We have previously shown that CaSR is expressed in primary bovine aortic vascular smooth muscle cells (VSMCs). Furthermore, dominant-negative adenoviral knockdown of this receptor in bovine VSMCs in vitro causes enhanced calcification in the presence of culture conditions which mimic vascular calcification in vivo. Using mineralising conditions in vitro, we have also previously demonstrated that positive pharmacological allosteric activation of CaSR using the calcimimetic, R-568, significantly reduces calcification of bovine VSMCs. These findings now implicate the CaSR, not just in systemic Ca2+ homeostasis, but also in potential protection against vascular calcification; a condition associated with increased blood pressure, left ventricular hypertrophy, chronic kidney disease and cardiovascular morbidity. Using a specific targeted deletion strategy, we have developed CaSR-specific knockout in VSMCs driven by the SM22α promoter. Using in vitro, ex vivo and in vivo approaches, here, I have characterised the cardiovascular phenotype of this novel transgenic mouse model. In vivo data demonstrate that ablation of CaSR from VSMCs causes hyperkalaemia at 3 months of age and hypercalcaemia throughout life. 3 month old CaSR-VSMC Knockout (KO) mice also exhibit reduced bone mineral integrity and increased heart weight at the age of 18 months. Ex vivo analysis implicates the VSMC-CaSR as a modulator of blood vessel tone. CaSR-VSMC KO mice exhibit reduced luminal diameters of the aorta and mesenteric arteries. CaSR-VSMC KO also reduces contractile tone in addition to evoking Ca2+-dependent relaxation only, compared to CaSR-wild-type (WT) mice which exhibit both Ca2+-dependent contraction and relaxation of the aorta. In vitro analyses confirm that CaSR expression and activation reduces Ca2+-dependent proliferation and mineralisation. In conclusion, the VSMC CaSR is a modulator of vascular tone ex vivo and of VSMC proliferation and calcification in vitro

    Brain Injury

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    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

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

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    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

    Front Lines of Thoracic Surgery

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    Front Lines of Thoracic Surgery collects up-to-date contributions on some of the most debated topics in today's clinical practice of cardiac, aortic, and general thoracic surgery,and anesthesia as viewed by authors personally involved in their evolution. The strong and genuine enthusiasm of the authors was clearly perceptible in all their contributions and I'm sure that will further stimulate the reader to understand their messages. Moreover, the strict adhesion of the authors' original observations and findings to the evidence base proves that facts are the best guarantee of scientific value. This is not a standard textbook where the whole discipline is organically presented, but authors' contributions are simply listed in their pertaining subclasses of Thoracic Surgery. I'm sure that this original and very promising editorial format which has and free availability at its core further increases this book's value and it will be of interest to healthcare professionals and scientists dedicated to this field
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