Atheromas of the thoracic aorta: clinical and therapeutic update

AbstractAtherosclerotic lesions of the thoracic aorta have recently been recognized as an important cause of stroke and peripheral embolization, which may result in severe neurologic damage as well as multiorgan failure and death. Their prevalence is ∼27% in patients with previous embolic events. Transesophageal echocardiography is the modality of choice for the diagnosis of these atheromas, although computed tomography, magnetic resonance imaging and intraoperative epiaortic ultrasound are complementary. Two clinical syndromes account for the embolic phenomena, atheroemboli and, more commonly, thromboemboli. In addition to such superimposed thrombi, plaque thickness (especially ≥4 mm) also correlates with embolic risk. This risk is high, with 12% of patients having a recurrent stroke within approximately one year, and up to 33% of patients having a stroke or peripheral embolus. In addition, aortic atheromas (as seen with intraoperative transesophageal echocardiography and intraoperative epiaortic ultrasound) are an important cause of stroke during heart surgery requiring cardiopulmonary bypass. Such strokes occur during ∼12% of cardiac operations employing cardiopulmonary bypass when aortic arch atheromas are seen with transesophageal echocardiography (six times the general intraoperative stroke rate). Although anticoagulant strategies have been reported with encouraging results in nonrandomized studies, prospective, randomized data must be developed before an effective and safe treatment strategy can be determined. This review details the current state of knowledge in this area, including the clinical and pathologic evidence that thoracic aortic atherosclerosis is an important embolic source, data which guide current therapy and future directions for clinical investigation

Discrete atherosclerotic coronary artery aneurysms: A study of 20 patients

The incidence, angiographic features and natural history of discrete atherosclerotic coronary aneurysms were evaluated in 20 patients with 22 aneurysms (0.2% of 8,422 patients referred for coronary angiography). Fifteen aneurysms (68%) were in the left anterior descending, four (18%) in the circumflex, two (9%) in the right and one (5%) in the left main coronary artery. Aneurysm diameter ranged from 4 to 35 mm (mean 8); 95% of aneurysms were adjacent to a severe obstruction.Seventy-five percent of patients had severe triple vessel disease that included severe left main disease in 15%. Total obstruction of one or two arteries was present in 75%. In patients with wall motion abnormalities, 78% of the abnormalities were in the distribution of the aneurysm. Follow-up (range 1 to 90 months [mean 30]) was obtained in all 20 patients. There were two cardiac and two noncardiac deaths; 12 patients had coronary bypass surgery and of 16 survivors, 13 were angina-free.In conclusion, discrete coronary aneurysms are much less common than diffuse ectasia. Unlike ectasia, they are never found in arteries without severe stenosis, and are most common in the left anterior descending coronary artery. Associated coronary artery disease is more severe in patients with discrete aneurysms than in those with diffuse ectasia. Discrete coronary aneurysms do not appear to rupture, and their resection is not warranted

Noninvasive diagnosis of left ventricular outflow tract obstruction caused by a porcine mitral prosthesis

A patient developed shortness of breath 8 years after mitral valve replacement with a porcine prosthesis. Doppler echocardiography revealed left ventricular outflow tract obstruction created by a protruding prosthesis

Проектування багатовимірних робастних систем керування польотом на основі процедур H∞-оптимізації та µ-синтеза

У статті розглядається синтез багатовимірної системи керування польотом, що заснований на технології μ-синтезу стосовно до завдання стабілізації висоти та швидкості польоту при дії зовнішніх збурень, обмежених по модулю. Показано, що за допомогою циклу μ-синтезу вирішення цієї задачі може бути отримане при наявності невизначеності не тільки параметрів, але й структури об’єкта, зокрема, для випадку повної нелінійної моделі літального апарата (ЛА). Метод μ-синтезу в цьому випадку є більш ефективним, ніж процедура H∞-оптимізації.In this paper robust multivariable flight control system synthesis based on the μ-synthesis technology is considered on the example of altitude and velocity stabilization in presence of atmospheric disturbances and parametric uncertainties of controlled plant. It is proved, that application of μ-synthesis can obtain solution in a class of linear, time-invariant systems of this problem not only for structured uncertainties, but for unstructured parametric uncertainties, including the change of the control plant’s model from linearized model to non-linear one. μ-synthesis method in this case is more efficient than the H∞-optimization procedure.В статье рассматривается синтез многомерной системы управления полётом, на основе технологии μ-синтеза применительно к задаче стабилизации высоты и скорости полёта при действии внешних возмущений, ограниченных по модулю. Показано, что с помощью цикла μ-синтеза решение этой задачи может быть получено при наличии неопределённости не только параметров, но и структуры объекта, в частности, для случая полной нелинейной модели летательного аппарата (ЛА). Метод μ-синтеза в этом случае является более эффективным, чем процедура H∞–оптимизации

Pilot-scale crossflow-microfiltration and pasteurization to remove spores of Bacillus anthracis (Sterne) from milk

High-temperature, short-time pasteurization of milk is ineffective against spore-forming bacteria such as Bacillus anthracis (BA), but is lethal to its vegetative cells. Crossflow microfiltration (MF) using ceramic membranes with a pore size of 1.4 μm has been shown to reject most microorganisms from skim milk; and, in combination with pasteurization, has been shown to extend its shelf life. The objectives of this study were to evaluate MF for its efficiency in removing spores of the attenuated Sterne strain of BA from milk; to evaluate the combined efficiency of MF using a 0.8-μm ceramic membrane, followed by pasteurization (72°C, 18.6 s); and to monitor any residual BA in the permeates when stored at temperatures of 4, 10, and 25°C for up to 28 d. In each trial, 95 L of raw skim milk was inoculated with about 6.5 log10 BA spores/mL of milk. It was then microfiltered in total recycle mode at 50°C using ceramic membranes with pore sizes of either 0.8 μm or 1.4 μm, at crossflow velocity of 6.2 m/s and transmembrane pressure of 127.6 kPa, conditions selected to exploit the selectivity of the membrane. Microfiltration using the 0.8-μm membrane removed 5.91 ± 0.05 log10 BA spores/mL of milk and the 1.4- μm membrane removed 4.50 ± 0.35 log10 BA spores/ mL of milk. The 0.8-μm membrane showed efficient removal of the native microflora and both membranes showed near complete transmission of the casein proteins. Spore germination was evident in the permeates obtained at 10, 30, and 120 min of MF time (0.8-μm membrane) but when stored at 4 or 10°C, spore levels were decreased to below detection levels (≤0.3 log10 spores/mL) by d 7 or 3 of storage, respectively. Permeates stored at 25°C showed coagulation and were not evaluated further. Pasteurization of the permeate samples immediately after MF resulted in additional spore germination that was related to the length of MF time. Pasteurized permeates obtained at 10 min of MF and stored at 4 or 10°C showed no growth of BA by d 7 and 3, respectively. Pasteurization of permeates obtained at 30 and 120 min of MF resulted in spore germination of up to 2.42 log10 BA spores/mL. Spore levels decreased over the length of the storage period at 4 or 10°C for the samples obtained at 30 min of MF but not for the samples obtained at 120 min of MF. This study confirms that MF using a 0.8-μm membrane before high-temperature, short-time pasteurization may improve the safety and quality of the fluid milk supply; however, the duration of MF should be limited to prevent spore germination following pasteurization

Horizontal Transmission and Recombination Maintain forever Young Bacterial Symbiont Genomes

Bacterial symbionts bring a wealth of functions to the associations they participate in, but by doing so, they endanger the genes and genomes underlying these abilities. When bacterial symbionts become obligately associated with their hosts, their genomes are thought to decay towards an organelle-like fate due to decreased homologous recombination and inef- ficient selection. However, numerous associations exist that counter these expectations, especially in marine environments, possibly due to ongoing horizontal gene flow. Despite extensive theoretical treatment, no empirical study thus far has connected these underlying population genetic processes with long-term evolutionary outcomes. By sampling marine chemosynthetic bacterial-bivalve endosymbioses that range from primarily vertical to strictly horizontal transmission, we tested this canonical theory. We found that transmission mode strongly predicts homologous recombination rates, and that exceedingly low recombination rates are associated with moderate genome degradation in the marine symbionts with nearly strict vertical transmission. Nonetheless, even the most degraded marine endosym- biont genomes are occasionally horizontally transmitted and are much larger than their ter- restrial insect symbiont counterparts. Therefore, horizontal transmission and recombination enable efficient natural selection to maintain intermediate symbiont genome sizes and sub- stantial functional genetic variation

Effect of guar gum on the physicochemical, thermal, rheological and textural properties of green edam cheese

In attempts to produce a low-fat cheese with a rheology and texture similar to that of a full-fat cheese, guar gum (within 0.0025–0.01%; w/v, final concentration) was added to low-fat milk. The obtained cheeses were characterised regarding their physicochemical, thermal, rheological and textural properties. Control cheeses were also produced with low and full-fat milk. The physicochemical properties of the guar gum modified cheeses were similar to those of the low-fat control. No significant differences were detected in the thermal properties (concerning the enthalpy and profile of water desorption) among all types of cheeses. The rheological behaviour of the 0.0025% modified cheese was very similar to the full-fat control. Overall, no trend was observed in the texture profile (hardness, cohesiveness, gumminess and elasticity) of the modified cheeses versus guar gum concentration, as well as in comparison with the control groups, suggesting that none of the studied polysaccharide concentrations simulated the textural functions of fat in Edam cheese

Detection of high cardiovascular risk patients with ankylosing spondylitis based on the assessment of abdominal aortic calcium as compared to carotid ultrasound

ABSTRACT: Background: This study aimed to determine whether, besides carotid ultrasound (US), a lateral lumbar spine radiography may also help identify ankylosing spondylitis (AS) patients at high risk of cardiovascular (CV) disease. Methods: A set of 125 AS patients older than 35 years without a history of CV events, diabetes mellitus, or chronic kidney disease was recruited. Carotid US and lateral lumbar spine radiography were performed in all of them. The CV risk was calculated according to the total cholesterol systematic coronary risk evaluation (TC- CORE) algorithm. Presence of carotid plaques was defined following the Mannheim Carotid Intima-media Thickness and Plaque Consensus. Abdominal aortic calcium (AAC) in a plain radiography was defined as calcific densities visible in an area parallel and anterior to the lumbar spine. Results: Carotid US showed higher sensitivity than lateral lumbar spine radiography to detect high CV risk in the 54 patients with moderate TC-SCORE (61% versus 38.9%). Using carotid plaques as the gold standard test, a predictive model that included a TC-SCORE >= 5% or the presence of AAC in the lateral lumbar spine radiography in patients with both moderate and low CV risk (< 5%) according to the TC-SCORE yielded a sensitivity of 50.9% with a specificity of 95.7% to identify high/very high CV-risk AS patients. A positive correlation between AAC and carotid plaques was observed (r2 = 0.49, p < 0.001). Conclusions: A lateral lumbar spine radiography is a useful tool to identify patients with AS at high risk of CV disease