Investigation of optimal sample preparation conditions with potassium triiodide and optimal imaging settings for microfocus computed tomography of excised cat hearts

OBJECTIVE: To determine optimal sample preparation conditions with potassium triiodide (I2KI) and optimal imaging settings for microfocus CT (micro-CT) of excised cat hearts. SAMPLE 7 excised hearts (weight range, 10 to 17.6 g) obtained from healthy adult cats after euthanasia by IV injection of pentobarbital sodium. PROCEDURES: Following excision, the hearts were preserved in 10% formaldehyde solution. Six hearts were immersed in 1.25% I2KI solution (n = 3) or 2.5% I2KI solution (3) for a 12-day period. Micro-CT images were acquired at time 0 (prior to iodination) then approximately every 24 and 48 hours thereafter to determine optimal sample preparation conditions (ie, immersion time and concentration of I2KI solution). Identified optimal conditions were then used to prepare the seventh heart for imaging; changes in voltage, current, exposure time, and gain on image quality were evaluated to determine optimal settings (ie, maximal signal-to-noise and contrast-to-noise ratios). Images were obtained at a voxel resolution of 30 mm. A detailed morphological assessment of the main cardiac structures of the seventh heart was then performed. RESULTS: Immersion in 2.5% I2KI solution for 48 hours was optimal for sample preparation. The optimal imaging conditions included a tube voltage of 100 kV, current of 150 mA, and exposure time of 354 milliseconds; scan duration was 12 minutes. CONCLUSIONS AND CLINICAL RELEVANCE: Results provided an optimal micro-CT imaging protocol for excised cat hearts prepared with I2KI solution that could serve as a basis for future studies of micro-CT for high resolution 3-D imaging of cat hearts

Shape Analysis and Computational Fluid Simulations to Assess Feline Left Atrial Function and Thrombogenesis

In humans, there is a well-established relationship between atrial fibrillation (AF), blood flow abnormalities and thrombus formation, even if there is no clear consensus on the role of left atrial appendage (LAA) morphologies. Cats can also suffer heart diseases, often leading to an enlargement of the left atrium that promotes stagnant blood flow, activating the clotting process and promoting feline aortic thromboembolism. The majority of pathological feline hearts have echocardiographic evidence of abnormal left ventricular filling, usually assessed with 2D and Doppler echocardiography and standard imaging tools. Actually, veterinary professionals have limited access to advanced computational techniques that would enable a better understanding of feline heart pathologies with improved morphological and haemodynamic descriptors. In this work, we applied state-of-the-art image processing and computational fluid simulations based on micro-computed tomography images acquired in 24 cases, including normal cats and cats with varying severity of cardiomyopathy. The main goal of the study was to identify differences in the LA/LAA morphologies and blood flow patterns in the analysed cohorts with respect to thrombus formation and cardiac pathology. The obtained results show significant differences between normal and pathological feline hearts, as well as in thrombus vs non-thrombus cases and asymptomatic vs symptomatic cases, while it was not possible to discern in congestive heart failure with thrombus and from non-thrombus cases. Additionally, in-silico fluid simulations demonstrated lower LAA blood flow velocities and higher thrombotic risk in the thrombus cases

Predator-Induced Vertical Behavior of a Ctenophore

Although many studies have focused on Mnemiopsis leidyi predation, little is known about the role of this ctenophore as prey when abundant in native and invaded pelagic systems. We examined the response of the ctenophore M. leidyi to the predatory ctenophore Beroe ovata in an experiment in which the two species could potentially sense each other while being physically separated. On average, M. leidyi responded to the predator’s presence by increasing variability in swimming speeds and by lowering their vertical distribution. Such behavior may help explain field records of vertical migration, as well as stratified and near-bottom distributions of M. leidyi

N-Methyl-D-aspartic Acid (NMDA) in the nervous system of the amphioxus Branchiostoma lanceolatum

<p>Abstract</p> <p>Background</p> <p>NMDA (<it>N</it>-methyl-D-aspartic acid) is a widely known agonist for a class of glutamate receptors, the NMDA type. Synthetic NMDA elicits very strong activity for the induction of hypothalamic factors and hypophyseal hormones in mammals. Moreover, endogenous NMDA has been found in rat, where it has a role in the induction of GnRH (Gonadotropin Releasing Hormone) in the hypothalamus, and of LH (Luteinizing Hormone) and PRL (Prolactin) in the pituitary gland.</p> <p>Results</p> <p>In this study we show evidence for the occurrence of endogenous NMDA in the amphioxus <it>Branchiostoma lanceolatum</it>. A relatively high concentration of NMDA occurs in the nervous system of this species (3.08 ± 0.37 nmol/g tissue in the nerve cord and 10.52 ± 1.41 nmol/g tissue in the cephalic vesicle). As in rat, in amphioxus NMDA is also biosynthesized from D-aspartic acid (D-Asp) by a NMDA synthase (also called D-aspartate methyl transferase).</p> <p>Conclusion</p> <p>Given the simplicity of the amphioxus nervous and endocrine systems compared to mammalian, the discovery of NMDA in this protochordate is important to gain insights into the role of endogenous NMDA in the nervous and endocrine systems of metazoans and particularly in the chordate lineage.</p

The 10th Biennial Hatter Cardiovascular Institute workshop: cellular protection—evaluating new directions in the setting of myocardial infarction, ischaemic stroke, and cardio-oncology

Due to its poor capacity for regeneration, the heart is particularly sensitive to the loss of contractile cardiomyocytes. The onslaught of damage caused by ischaemia and reperfusion, occurring during an acute myocardial infarction and the subsequent reperfusion therapy, can wipe out upwards of a billion cardiomyocytes. A similar program of cell death can cause the irreversible loss of neurons in ischaemic stroke. Similar pathways of lethal cell injury can contribute to other pathologies such as left ventricular dysfunction and heart failure caused by cancer therapy. Consequently, strategies designed to protect the heart from lethal cell injury have the potential to be applicable across all three pathologies. The investigators meeting at the 10th Hatter Cardiovascular Institute workshop examined the parallels between ST-segment elevation myocardial infarction (STEMI), ischaemic stroke, and other pathologies that cause the loss of cardiomyocytes including cancer therapeutic cardiotoxicity. They examined the prospects for protection by remote ischaemic conditioning (RIC) in each scenario, and evaluated impasses and novel opportunities for cellular protection, with the future landscape for RIC in the clinical setting to be determined by the outcome of the large ERIC-PPCI/CONDI2 study. It was agreed that the way forward must include measures to improve experimental methodologies, such that they better reflect the clinical scenario and to judiciously select combinations of therapies targeting specific pathways of cellular death and injury

Perceived Discrimination and Health Outcomes Among Asian Indians in the United States

Background: Perceived interpersonal discrimination while seeking healthcare services is associated with poor physical and mental health. Yet, there is a paucity of research among Asian Americans or its subgroups. This study examined the correlates of reported interpersonal discrimination when seeking health care among a large sample of Asian Indians, the 3rd largest Asian American subgroup in the US, and identify predictors of adverse self-rated physical health, a well-accepted measure of overall health status. Methods: Cross-sectional survey. Participants comprised of 1824 Asian Indian adults in six states with higher concentration of Asian Indians. Results: Mean age and years lived in the US was 45.7 ± 12.8 and 16.6 ± 11.1 years respectively. The majority of the respondents was male, immigrants, college graduates, and had access to care. Perceived interpersonal discrimination when seeking health care was reported by a relatively small proportion of the population (7.2 %). However, Asian Indians who reported poor self-rated health were approximately twice as likely to perceived discrimination when seeking care as compared to those in good or excellent health status (OR 1.88; 95 % CI 1.12–3. 14). Poor self-rated health was associated with perceived health care discrimination after controlling for all of the respondent characteristics (OR 1.93; 95 % CI: 1.17–3.19). In addition, Asian Indians who lived for more than 10 years in the U.S. (OR 3.28; 95 % CI: 1.73–6.22) and had chronic illnesses (OR 1.39; 95 % CI: 1.17–1.64) (p \u3c 0.05) were more likely to perceive discrimination when seeking health care. However, older Asian Indians, over the age of 55 years, were less likely to perceive discrimination than those aged 18–34 years Indian American. Conclusion: Results offers initial support for the hypothesis that Asian Indians experience interpersonal discrimination when seeking health care services and that these experiences may be related to poor self-rated health status

From basic mechanisms to clinical applications in heart protection, new players in cardiovascular diseases and cardiac theranostics: meeting report from the third international symposium on "New frontiers in cardiovascular research"

In this meeting report, particularly addressing the topic of protection of the cardiovascular system from ischemia/reperfusion injury, highlights are presented that relate to conditioning strategies of the heart with respect to molecular mechanisms and outcome in patients' cohorts, the influence of co-morbidities and medications, as well as the contribution of innate immune reactions in cardioprotection. Moreover, developmental or systems biology approaches bear great potential in systematically uncovering unexpected components involved in ischemia-reperfusion injury or heart regeneration. Based on the characterization of particular platelet integrins, mitochondrial redox-linked proteins, or lipid-diol compounds in cardiovascular diseases, their targeting by newly developed theranostics and technologies opens new avenues for diagnosis and therapy of myocardial infarction to improve the patients' outcome

Temporal controls on silicic acid utilisation along the West Antarctic Peninsula

The impact of climatic change along the Antarctica Peninsula has been widely debated in light of atmospheric/oceanic warming and increases in glacial melt over the past half century. Particular concern exists over the impact of these changes on marine ecosystems, not only on primary producers but also on higher trophic levels. Here we present a record detailing the historical controls on the biogeochemical cycling of silicic acid [Si(OH)4] on the west Antarctica Peninsula margin, a region in which the modern phytoplankton environment is constrained by seasonal sea-ice. We demonstrate that Si(OH)4 cycling through the Holocene alternates between being primarily regulated by sea-ice or glacial discharge from the surrounding grounded ice-sheet. With further climate-driven change and melting forecast for the 21st Century, our findings document the potential for biogeochemical cycling and multi-trophic interactions along the peninsula to be increasingly regulated by glacial discharge, altering food-web interactions