Background: Debate continues as to whether being young confers a worse prognosis for patients with squamous cell carcinoma of the tongue. Recent papers have provided conflicting views in this debate. In this study we aimed to investigate if young age at the time of diagnosis of squamous cell carcinoma of the tongue confers a worse prognosis. Methods: Eligible patients were identified through the computer database of the Department of Radiation Oncology, Westmead Hospital, Sydney. All eligible patients were treated with radical intent. Using age 40 as a cut off multivariate and survival analysis was undertaken to compare age groups. Results: Median age at diagnosis was 60 years (range, 19-86 years) in 84 males (65 per cent) and 45 females (35 per cent). Median follow-up time was 43 months (range, 2.3-203 months). Fifteen patients (12 per cent) were aged <40 years. On univariate analysis stage and age were significant determinants of disease-specific survival. There was no difference in overall survival between the young (<40 years) and middle-aged groups (40-60 years). However, the young and the middle aged were both more likely to survive than the older age group (>60 years). On multivariate analysis age remained a significant factor for determining disease-specific survival, with the older age group 2.9 times more likely to die than the younger groups. Conclusion: Young age (<40 years) did not portend to worse survival in comparison to older tongue cancer patients.

Background: Until recently, very few papers have been published concerning the development, analysis and experimental verification of three-dimensional, finite element modelling of the human adult edentulous mandible. The purpose of this study was to improve the method of modelling by using computer-aided engineering (CAE) and computeraided design (CAD) methods and to utilize the model in analyzing maxillofacial problems. Methods: The model geometry was derived from position measurements taken from 28 diamond blade cut cross-sections of an average size human adult edentulous mandible and generated using a special sequencing method. Data on anatomical, structural, functional aspects and material properties were obtained from measurements and published data. The materials were idealized as transversely isotropic. The complete model consisted of 258 solid elements and 1635 nodes. Results: The model was solved for displacements and stresses during clenching. In general, the observed displacement and stresses (tensile and compressive) were highest around the condylar region. Compressive stress was also observed around the premolar and molar bite points. Conclusion: This investigation has shown that the use of computer-aided modelling in conjunction with the finite element analysis could be effectively utilized in biomechanical analysis of the mandible. It could help to investigate many functional problems and could reduce the time of extensive experimentations.Key words: Finite element analysis, three-dimensional modelling, human mandible, clenching, muscle forces.Abbreviations and acronyms: CAD = computer-aided design; CAE = computer-aided engineering; CT = computer-aided tomography; FEA = finite element analysis; IEMG = integrated electromyogram; PC = personal computer; TMJ = temporomandibular joint.

Developments in diagnosis and treatment have transformed the management of blunt thoracic aortic injuries (BTAIs). For patients in stable condition, treatment practice has shifted from early open repair to nonoperative management for low-grade lesions and routine delayed endovascular repair for more significant injuries. However, effective therapy depends on accurate staging of injury grade and stability to select patients for appropriate management. Recent developments in BTAI risk stratification enable lesion-specific management tailored to the patient and aortic lesion. This review summarizes advances in lesion assessment and treatment and proposes an integrated scheme for the modern management of BTAI.

Thrombotic and bleeding complications are the major obstacles for expanding mechanical circulatory support (MCS) beyond the current use. While providing the needed hemodynamic support, those devices can induce damage to blood, particularly to platelets. In this study, we investigated device‐induced alteration of three major platelet surface receptors, von Willebrand factor (VWF) and associated hemostatic functions relevant to thrombosis and bleeding. Fresh human whole blood was circulated in an extracorporeal circuit with a clinical rotary blood pump (CentriMag, Abbott, Chicago, IL, USA) under the clinically relevant operating condition for 4 hours. Blood samples were examined every hour for glycoprotein (GP) IIb/IIIa activation and receptor loss of GPVI and GPIbα on the platelet surface with flow cytometry. Soluble P‐selectin in hourly collected blood samples was measured by enzyme linked immunosorbent assay to characterize platelet activation. Adhesion of device‐injured platelets to fibrinogen, collagen, and VWF was quantified with fluorescent microscopy. Device‐induced damage to VWF was characterized with western blotting. The CentriMag blood pump induced progressive platelet activation with blood circulating time. Particularly, GPIIb/IIIa activation increased from 1.1% (Base) to 11% (4 hours) and soluble P‐selectin concentration increased from 14.1 ng/mL (Base) to 26.5 ng/mL (4 hours). Those device‐activated platelets exhibited increased adhesion capacity to fibrinogen. Concurrently, the CentriMag blood pump caused progressive platelet receptor loss (GPVI and GPIbα) with blood circulating time. Specifically, MFI of the GPVI and GPIbα receptors decreased by 17.2% and 16.1% for the 4‐hours sample compared to the baseline samples, respectively. The device‐injured platelets exhibited reduced adhesion capacities to collagen and VWF. The high molecular weight multimers (HMWM) of VWF in the blood disappeared within the first hour of the circulation. Thereafter the multimeric patterns of VWF were stable. The change in the VWF multimeric pattern was different from the progressive structural and functional changes of platelets with the circulation time. This study suggested that the CentriMag blood pump could induce two opposite effects on platelets and associated hemostatic functions under a clinically relevant operating condition. The device‐altered hemostatic function may contribute to thrombosis and bleeding simultaneously as occurring in patients supported by a rotary blood pump. Device‐induced damage of platelets may be an important cause for bleeding in patients supported with rotary blood pump MCS systems relative to device‐induced loss of HMWM‐VWF.

Conventional angiography is the current standard for the evaluation of carotid artery disease. The excellent resolution of this invasive study is offset by the potential for contrast-related, embolic, and puncture site complications. Three-dimensional magnetic resonance angiography may offer a noninvasive diagnostic alternative. We examined this possibility by performing both conventional angiography and three-dimensional magnetic resonance angiography in 13 patients. Cervical duplex scans were also obtained in these patients. Contiguous transverse cervical magnetic resonance images were acquired in a 1.5 tesla magnet, by use of a posterior neck coil and a gradient echo pulse sequence. These "raw" data were transferred to a real-time workstation where three-dimensional cervical arterial images were reformatted, magnified, and examined from multiple angles. Total study time from patient positioning to image generation was approximately 30 minutes. In all patients, on three-dimensional magnetic resonance angiography the common, external, and internal carotid arteries and distal vertebral arteries were easily discernable and correctly identified as patent, stenotic, or occluded. Three-dimensional magnetic resonance angiography was not accurate in detecting carotid ulcers. The degree of internal carotid artery stenosis measured from the three-dimensional magnetic resonance angiography studies correlated well with the internal carotid artery stenosis measured with conventional angiography (r = 0.866, r2 = 75.1%, p = less than or equal to 0.0001). This recent technologic advance represents significant progress toward achieving the goal of completely noninvasive vascular assessment in this patient population.

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Extracorporeal membrane oxygenation (ECMO) has become a mainstay of therapy for patients suffering from severe respiratory failure. Ambulatory ECMO systems aim to provide long-term out-of-hospital respiratory support. As a patient's activity level changes, the required level of ECMO support varies with oxygen consumption and metabolic fluctuations. To compensate for such changes, an autoregulatory ECMO system (AR-ECMO) has been developed and its performance was evaluated as a proof of concept in an acute ovine model. The AR-ECMO system consists of a regular ECMO circuit and an electromechanical control system. A custom fuzzy logic control algorithm was implemented to adjust the blood flow and sweep gas flow of the ECMO circuit to meet the varying respiratory demand by utilizing two noninvasive sensors for venous oxyhemoglobin saturation and the oxygenator exhaust gas CO 2 concentration. Disturbance responses of the AR-ECMO to induced acute respiratory distress were assessed for six hours in four juvenile sheep cannulated with a veno-pulmonary artery ECMO configuration, including acute ventilator shutoff, ventilator step change (off-on-off), and forced desaturation. All sheep survived for the study duration. The AR-ECMO system was able to respond and maintain stable hemodynamics and physiological blood gas contents (SpO 2 = 96.3 % ± 4.29, pH 7.44 ± 0.09, pCO 2 = 38.9 ± 9.9 mm Hg, and pO 2 =237.9 ± 123.6 mm Hg) during simulated respiratory distress. Acceptable correlation between oxygenator exhaust gas CO 2 and oxygenator outlet pCO 2 were observed (R 2 = 0.84). In summary, the AR-ECMO system successfully maintained physiologic control of peripheral oxygenation and carbon dioxide over the study period, utilizing only measurements taken directly from the ECMO circuit. The range of system response necessitates an adaptable system in the setting of variable metabolic demands. The ability of this system to respond to significant disturbances in ventilator support is encouraging.Future work to evaluate our AR-ECMO system in long-term, awake animal studies is necessary for further refinement. K E Y W O R D Sartificial lung, autoregulatory control, extracorporeal membrane oxygenation, respiratory distress | 479 CONWAY et Al.

Introduction: Extracorporeal membrane oxygenation circuit performance can be compromised by oxygenator thrombosis. Stagnant blood flow in the oxygenator can increase the risk of thrombus formation. To minimize thrombogenic potential, computational fluid dynamics is frequently applied for identification of stagnant flow conditions. We investigate the use of computed tomography angiography to identify flow patterns associated with thrombus formation. Methods: A computed tomography angiography was performed on a Quadrox D oxygenator, and video densitometric parameters associated with flow stagnation were measured from the acquired videos. Computational fluid dynamics analysis of the same oxygenator was performed to establish computational fluid dynamics–based flow characteristics. Forty-one Quadrox D oxygenators were sectioned following completion of clinical use. Section images were analyzed with software to determine oxygenator clot burden. Linear regression was used to correlate clot burden to computed tomography angiography and computational fluid dynamics–based flow characteristics. Results: Clot burden from the explanted oxygenators demonstrated a well-defined pattern, with the largest clot burden at the corner opposite the blood inlet and outlet. The regression model predicted clot burden by region of interest as a function of time to first opacification on computed tomography angiography (R2 = 0.55). The explanted oxygenator clot burden map agreed well with the computed tomography angiography predicted clot burden map. The computational fluid dynamics parameter of residence time, when summed in the Z-direction, was partially predictive of clot burden (R2 = 0.35). Conclusion: In the studied oxygenator, clot burden follows a pattern consistent with clinical observations. Computed tomography angiography–based flow analysis provides a useful adjunct to computational fluid dynamics–based flow analysis in understanding oxygenator thrombus formation.