1,165 research outputs found

    Impaired Poststenotic Aortic Pulsatility After Hemodynamically Ideal Coarctation Repair in Children

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    Using echocardiographic quantification of aortic pulsatility distal to the site of the surgical anastomosis, we evaluated whether the preoperatively impaired poststenotic aortic pulsatility returned to normal after repair of coarctation with a hemodynamically ideal result. Patients who underwent repair of aortic coarctation without residual obstruction were compared to a matched group of normal children. A standardized M-mode echocardiographic evaluation of the aorta at the diaphragmatic level was performed for all patients. Measurements consisted of maximum and minimum aortic diameters, time intervals, and a calculated pulsatility index. Compared to normal children (n = 19), 20 children with operated coarctation and with a hemodynamically ideal result showed a significantly smaller increase in aortic diameter in systole (mean of 29 ± 7% in patients versus 37 ± 7% in normals; p < 0.01). In contrast to patients with coarctation in whom the maximum aortic distension is reached much later during the cardiac cycle, hemodynamically normalized, operated patients in our study had no such delay (maximum aortic pulsation at 28% of cardiac cycle time compared to 27% in normals; p = not significant). The pulsatility index of the poststenotic aorta was clearly lower in operated children (mean, 130 ± 50%/sec) compared to a normal mean value of 202 ± 33%/sec but was still significantly higher than that in patients with unoperated coarctation, who showed a low mean value of 51 ± 24%/sec (p < 0.01). After correction of aortic coarctation with a hemodynamically ideal result, the pulsatility of the poststenotic aorta, severely impaired prior to repair, did not return to normal during the observation period in the patients studie

    Predicting Avian Influenza Co-Infection with H5N1 and H9N2 in Northern Egypt.

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    Human outbreaks with avian influenza have been, so far, constrained by poor viral adaptation to non-avian hosts. This could be overcome via co-infection, whereby two strains share genetic material, allowing new hybrid strains to emerge. Identifying areas where co-infection is most likely can help target spaces for increased surveillance. Ecological niche modeling using remotely-sensed data can be used for this purpose. H5N1 and H9N2 influenza subtypes are endemic in Egyptian poultry. From 2006 to 2015, over 20,000 poultry and wild birds were tested at farms and live bird markets. Using ecological niche modeling we identified environmental, behavioral, and population characteristics of H5N1 and H9N2 niches within Egypt. Niches differed markedly by subtype. The subtype niches were combined to model co-infection potential with known occurrences used for validation. The distance to live bird markets was a strong predictor of co-infection. Using only single-subtype influenza outbreaks and publicly available ecological data, we identified areas of co-infection potential with high accuracy (area under the receiver operating characteristic (ROC) curve (AUC) 0.991)

    Delayed visceral malperfusion in aortic dissection—successful surgical revascularization using a saphenous vein graft

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    Obstruction of the thoracoabdominal aorta and/or its branches with subsequent organ ischemia is a frequent complication of aortic dissection. Surgical and percutaneous fenestrations have been used and endovascular stenting has emerged as an additional less invasive approach. In some cases, surgical revascularization may be the most successful procedure. We report two patients who underwent surgical revascularization of the celiac trunk and superior mesenteric artery for delayed abdominal malperfusion due to aortic dissectio

    Constrictive tuberculous pericarditis in a HIV-positive patient

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    Constrictive pericarditis is a relatively rare clinical manifestation nowadays. We present the case of an HIV-positive patient with constrictive calcified pericarditis due to an infection with Mycobacterium tuberculosis. Pericardectomie was performed. The therapeutical approach is discussed and the literature is reviewe

    A framework for evaluating operations control on a metro line: integrating multiple perspectives and automatically collected train and passenger movement data

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    Transit operations control, the task of implementing the operations plan in daily operations on a metro line, plays a key role in service delivery because it determines the quality of the service experienced by passengers. Yet, it is one of the most poorly understood aspects of rail transit operations. Faced with a disruption or infeasibility, dispatchers typically choose between several response strategies. However, to date, it has been very difficult to evaluate the positive and negative effects of individual control strategies with respect to operations and passenger travel times under real-world conditions. This paper proposes a framework for the study of rail operations control decisions that integrates automatically collected service and passenger demand data, which are increasingly available and accessible to transit agencies. The framework supports a multiperspective analysis methodology that can inform operational policies and plans, and help operations control decision-makers choose the most appropriate strategies to manage service. By using automatically collected data, taking into consideration the operations control decision environment, and acknowledging that the reliability of the resulting service depends on many factors endogenous to it, this paper takes a distinctly different approach from previous studies, which have relied heavily on modeling, assumed simple operating contexts, and did not consider the full range of available data. Two real-world applications of the framework, where control decisions are evaluated in terms of their operational and passenger impacts, are presented. The methodology is found to be versatile and valuable in providing insights that could not have been gained otherwise. Although the framework is applied to the London Underground, its logic, structure, and procedures are applicable and transferable to other metro systems recognizing that certain specifics would need to be tailored to the available data.Transport for London (Organization

    Aprotinin reduces blood loss in off-pump coronary artery bypass (OPCAB) surgery

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    Objective: Effects of aprotinin in off-pump coronary artery bypass (OPCAB) surgery have not yet been described. This study analyses hemostasiologic changes and potential benefit in OPCAB patients treated with aprotinin. Methods: In a prospective, double-blind, randomized study 47 patients undergoing OPCAB surgery were investigated. Patients received either aprotinin (2×106 KIU loading dose and 0.5×106 KIU/h during surgery, n=22) or saline solution (control, n=25). Activated clotting time was adjusted to a target of 250 s intraoperatively. Blood samples were taken up to 18 h postoperatively: complete hematologic and hemostasiologic parameters including fibrinopeptide A (FPA) and D-dimer in a subgroup of 31 patients were analyzed. Blood loss, blood transfusion and other clinical data were collected. Results: Both groups showed comparable demographic and intraoperative variables. Forty-one (87%) patients of the whole study group received aspirin within 7 days prior to surgery. Number of grafts per patient were comparable (2.9±1.0 [mean±SD] in the aprotinin group and 2.8±1.2 in control, P=0.83). Blood loss during the first 18 h in intensive care unit was significantly reduced in patients treated with aprotinin (median [25th-75th percentiles]: 500 [395-755] ml vs. 930 [800-1170] ml, P<0.001). Postoperatively only two patients (10%) in the aprotinin group received packed red blood cells, whereas eight (35%) in the control group (P=0.07). Perioperatively FPA levels reflecting thrombin generation were elevated in both groups. The increase in D-dimer levels after surgery was significantly inhibited in the aprotinin group (P<0.001). Early clinical outcome was similar in both groups. Conclusions: Aprotinin significantly reduces blood loss in patients undergoing OPCAB surgery. Inhibition of enhanced fibrinolysis can be observed. FPA generation during and after OPCAB surgery seems not to be influenced by aprotini

    Aprotinin reduces blood loss in off-pump coronary artery bypass (OPCAB) surgery

    Get PDF
    Objective: Effects of aprotinin in off-pump coronary artery bypass (OPCAB) surgery have not yet been described. This study analyses hemostasiologic changes and potential benefit in OPCAB patients treated with aprotinin. Methods: In a prospective, double-blind, randomized study 47 patients undergoing OPCAB surgery were investigated. Patients received either aprotinin (2×10 superscript 6 KIU loading dose and 0.5×10 superscript 6 KIU/h during surgery, n=22) or saline solution (control, n=25). Activated clotting time was adjusted to a target of 250 s intraoperatively. Blood samples were taken up to 18 h postoperatively: complete hematologic and hemostasiologic parameters including fibrinopeptide A (FPA) and D-dimer in a subgroup of 31 patients were analyzed. Blood loss, blood transfusion and other clinical data were collected. Results: Both groups showed comparable demographic and intraoperative variables. Forty-one (87%) patients of the whole study group received aspirin within 7 days prior to surgery. Number of grafts per patient were comparable (2.9±1.0 [mean±SD] in the aprotinin group and 2.8±1.2 in control, P=0.83). Blood loss during the first 18 h in intensive care unit was significantly reduced in patients treated with aprotinin (median [25th–75th percentiles]: 500 [395–755] ml vs. 930 [800–1170] ml, P<0.001). Postoperatively only two patients (10%) in the aprotinin group received packed red blood cells, whereas eight (35%) in the control group (P=0.07). Perioperatively FPA levels reflecting thrombin generation were elevated in both groups. The increase in D-dimer levels after surgery was significantly inhibited in the aprotinin group (P<0.001). Early clinical outcome was similar in both groups. Conclusions: Aprotinin significantly reduces blood loss in patients undergoing OPCAB surgery. Inhibition of enhanced fibrinolysis can be observed. FPA generation during and after OPCAB surgery seems not to be influenced by aprotinin

    Transplantation of a Human Mammary Carcinoma Cell Line (BT 20) Into Nude Mice

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    Cell suspensions of a human mammary carcinoma cell line (BT 20), when injected subcutaneously into nude athymic mice (BALB/c Nu/Nu), produced tumor nodules at the injection site. Subsequent serial transplantations also gave rise to neoplastic nodules after latency periods averaging 3 weeks. The nodules displayed morphologic and functional characteristics comparable to those of the original tumor cells. Metastases, however, were not observed in any of the tumor-bearing mic

    Rat Heterotopic Heart Transplantation Model to Investigate Unloading-Induced Myocardial Remodeling

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    Unloading of the failing left ventricle in order to achieve myocardial reverse remodeling and improvement of contractile function has been developed as a strategy with the increasing frequency of implantation of left ventricular assist devices (LVADs) in clinical practice. But, reverse remodeling remains an elusive target, with high variability and exact mechanisms still largely unclear. The small animal model of heterotopic heart transplantation in rodents has been widely implemented to study the effects of complete and partial unloading on cardiac failing and non-failing tissue to better understand the structural and molecular changes that underlie myocardial recovery not only of contractile function.We herein review the current knowledge on the effects of volume-unloading the left ventricle via different methods of heterotopic heart transplantation in rats, differentiating between changes that contribute to functional recovery and adverse effects observed in unloaded myocardium. We focus on methodological aspects of heterotopic transplantation, which increase the correlation between the animal model and the setting of the failing unloaded human heart. Last, but not least, we describe the late use of sophisticated techniques to acquire data, such as small animal MRI and catheterization, as well as ways to assess unloaded hearts under reloaded conditions.While giving regard to certain limitations, heterotopic rat heart transplantation certainly represents the crucial model to mimic unloading-induced remodeling of the heart and as such the intricacies and challenges deserve highest consideration. Careful translational research will further our knowledge of the reverse remodeling process and how to potentiate its effect in order to achieve recovery of contractile function in more patients
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