bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantitative and Qualitative Evaluation of Blood Salvaged after Extracorporeal Circulation (ECC) in Paediatric Heart Surgery
Authors: Calza G. , Zannini L. , Lerzo F. , Nitti P. , Mangraviti S. , Perutelli P. , Porlezza M. 
Published: March 2018

The salvaging of ECC circuit priming blood is essential for reducing the morbidity related to homologous blood transfusions and the importance of this technique is inversely proportionate to the age and weight of the child. In infants, the washing and centrifugation of blood not only drastically reduce the risk of contracting blood-transmitted diseases and cut management costs, but are also of considerable hemodynamic importance, producing a rapid normalization of the patient's hematocrit and hemoglobin and balancing the O2 consumption/demand ratio. The marketing of miniaturized salvaging devices with 55 ml bowls by Dideco has made possible the recovery of small quantities of blood, so as to normalise the hematic crisis and permit the application of total hemodilution in low-weight patients. The salvaged blood shows an average hematocrit of 52.7±9.7% (max 68.1%) and an average hemoglobin of 17.6±2.9 g/dl (max 20.7 g/dl), and maintains its structural components, osmotic resistance, concentration of intraerythrocytic hemoglobin and mean corpuscular hemoglobin all intact. Washing with isoosmotic and isoionic hydroelectrolytic solutions normalizes the ionic situation in the post-operative period and activated blood salvaging after Extracorporeal Circulation. The use of solutions without nutritional substances results however in a considerable fall in the number of enzymes in the intraerythrocytic metabolic glucide chain (G6PDH: −40.7±14.3% p<0.001), (PK: −23.8±20.5% p<0.03). This drop may be responsible for erythrocytic morphological alterations (echinocytic change) and probably for the release of hemoglobin from the red blood cells. Washing with isoionic, isoosmotic solutions containing G5% and adenine could, at least in theory, improve the quality of the salvaged blood, by normalizing the morphology and the volume of the RBC and by increasing the hematocrit.
Design and in vitro Testing of a Voice-Producing Element for Laryngectomized Patients
Authors: De Vries M.P. , Van Der Plaats A. , Van Der Torn M. , Mahieu H.F. , Schutte H.K. , Verkerke G.J. 
Published: March 2018

A voice-producing element has been developed to improve speech quality after laryngectomy. The design process started with the formulation of a list of requirements. The lip principle has the best potential for fulfilling the requirements. A numerical model was made to find the optimal geometry of an element based on the lip principle. Extensive in vitro tests were performed to check all requirements. For this a test set-up with realistic acoustic and aerodynamic properties was developed. Results show that the protruding lip length dominates fundamental frequency, cross-sectional area dominates flow resistance and relation between flow and fundamental frequency. Most requirements have been fullfilled; both for males and females a potentially good functioning prototype could be selected. Clinical experiments will be performed to confirm the quality of the voice-producing prosthesis.
A Physical Model of the Human Systemic Arterial Tree
Authors: Ferrari G. , Nicoletti A. , De Lazzari C. , Clemente F. , Tosti G. , Guaragno M. , Mimmo R. , Ambrosi D. , Górczyńaska K. 
Published: March 2018

A physical model of the human arterial tree has been developed to be used in a computer controlled mock circulatory system (MCS). Its aim is to represent systemic arterial tree properties and extend the capacity of the MCS to intraortic balloon pump (IABP) testing. The main problem was to model the aorta simply and to accurately reproduce aortic impedance and related flow and pressure waveforms at different sections. The model is composed of eight segments; lumped parameter models are used for its peripheral loads. After the numerical simulation, the physical model was reproduced as a silicon rubber tapered tube. This rubber was chosen for its stability over time and the acceptable behaviour of its Young's modulus (Ey =22.23 gf·mm–2) with different loads and in comparison with data from the literature (Ey ≈ 20.4 gf·mm–2). The properties of each segment of the aorta were defined in terms of compliance, resistance and inertance as a function of length, radius and thickness. The variable thickness was obtained using positive and negative molds. Total static compliance of the aorta model is about 1.125·10–3 g–1cm4·sec2 (1.5 cm3·mmHg–1). Measurements were performed both on numerical and physical models (in open and closed loop configuration). Data reported show pressure and flow waveforms along with input impedance modulus and phase. The results are in good agreement with data from the literature.
Artificial Trachea and Long Term follow-up in Carinal Reconstruction in Dogs
Authors: Nakamura T. , Teramachi M. , Sekine T. , Kawanami R. , Fukuda S. , Yoshitani M. , Toba T. , Ueda H. , Hori Y. , Inoue M. , Shigeno K. , Taka T. Nakahara , Liu Y. , Tamura N. , Shimizu Y. 
Published: March 2018

We have already reported “del” successful carinal reconstruction of the trachea with an observation period of 1 – 2 years. In this study, we evaluate the long-term safety and efficacy of the reconstruction after 5-years of follow-up. The Y-shaped Marlex® mesh tube was reinforced with a polypropylene spiral and coated with atelocollagen made from porcine skin. The prosthesis was 60 mm long with an outer diameter of 18 mm. Replacement of the tracheobronchial bifurcation was preformed through a right thoracotomy in a beagle dog. Bronchoscopical examination and sampling of the tracheal epithelium was performed periodically to check the function of cilia. The implanted prothesis was promptly infiltrated by the surrounding connective tissue and completely incorporated by the host trachea and bronchus. Bronchoscopically, sufficient epithelization was confirmed from the upper to the lower site of anastomosis. After 5 years neither stenosis nor dehiscence was observed. In spite of there being mesh-exposure at the luminal surface, the dog had no clinical symptoms until sacrifice for pathological examination. The bent frequency of the cilia was maintained within the normal range, indicating “del” functional recovery of the regenerating airway. Our tracheal prosthesis is promising for clinical “del” repair of the tracheobronchial bifurcation.
Numerical Simulation of the Influence of a Left Ventricular Assist Device on the Cardiovascular System
Authors: Verkerke G.J. , Geertsema A.A. , Mihaylov D. , Blanksma P.K. , Rakhorst G. 
Published: March 2018

The PUCA (pulsatile catheter) pump is a left ventricular assist device (LVAD) capable of unloading the left ventricle (LV) and improving coronary flow by providing a counterpulsation effect. It consists of an extracorporeal located membrane pump, coupled to a transarterial catheter that enters the body via a superficial artery and ends in the LV. Blood is aspirated from the LV and pumped in the ascending aorta through the same catheter guided by a valve system. Timing and frequency of the PUCA pump influence its efficacy. To study the influence of several pump parameters a numerical model of the device and the circulatory system has been developed. Results of animal experiments were used to validate the model. Optimization studies resulted in a pump configuration with a stroke volume of 50 cc and pump:heart frequency mode of 1:2 that starts ejection at the beginning of diastole.
Biomaterials in Spinal Fixation. An Experimental Animal Study to Improve the Performance
Authors: Rocca M. , Fini M. , Greggi T. , Parisini P. , Carpi A. , Giardino R. 
Published: March 2018

Different pedicle screws were biomechanically and morphologically studied and compared through the use of an animal model to determine their efficacy and resistance in spinal fixation. The principal objective was to compare biomechanical and histomorphological aspects of HA-coated screws to uncoated ones. Fourty-eight cylindrical transpedicular self-tapping screws divided into three groups of sixteen each were employed; Group A: stainless steel screws; Group B: titanium screws; Group C: HA-coated titanium screws. The screws were implanted bilaterally and randomly into the L3, L4, and L5 pedicles of eight adult mongrel sheep. The final insertion torque was measured in all the implants. After one and four months, upon euthanization, four samples per group were extracted from the surrounding bone and the screw extraction torque was measured. The remaining samples were examined and processed for histological and histomorphological evaluations. No differences were observed at one month among the extraction torque of the three groups. After four months the only significance between insertion and extraction values was for the HA group, i.e. p=0.001. Comparing the extraction torque values of the three groups after four months of healing, the HA-coated group showed a greater than twofold increase (p<0.0005). No differences were observed at one month among the percentages of bone-implant contact in the three groups. After four months the percentage was significant only for the C group (p<0.0005). At four months a correlation was found between the morphological and the biomechanical data of group C (p<0.0005). The use of hydroxyapatite-coated screws could act as an effective method to improve the bone-implant interface, thus obtaining a strong fixation of the implant independently of the arthrodesis achieved with bone graft.
Therapeutic Apheresis in Children: Experience in a Pediatric Dialysis Center
Authors: De Palo T. , Giordano M. , Bellantuono R. , Colella V. , Troise D. , Palumbo F. , Caringella D.A. 
Published: March 2018

The use of apheretic procedures in pediatric patients has always been restricted by technical difficulties and the low incidence of diseases requiring this kind of treatment. The aim of the present study was to describe the solutions adopted to solve technical difficulties related to priming, vascular access and monitoring and then to evaluate clinical results. Between 1982 and 2000, 51 consecutive children (28 male, 23 female) with a mean age of 4.9 ± 4.8 years (3 months – 14.8 years) and a mean weight of 19.7 ± 12.8 kg (5 – 52 kg), with renal and/or extra-renal diseases requiring apheretic procedures were selected for the study. The overall number of procedures performed were: 226 plasma-exchange (PE), 6 LDL-apheresis (LDL-A) and 8 protein A immunoadsorption (IAPA) sessions. Our therapeutic protocol involves hematic flux of 20 – 100 ml/min and ultrafiltration of 5–20 ml/min. In each 70–95 minute session we exchanged plasmatic volume with fresh frozen plasma or with a solution of 6% albumin in lactated Ringer's, using heparin (10–20 UI/kg/h). We used Paired Filtration Dialysis Monitor in PE and LDL-A; Citem 10 in IAPA. As plasma separator, we used a filter made of polypropylene, 0.2 m2 surface, 30 ml priming (Hemaplex BT 900). Hemolytic uremic syndrome was the most commonly treated disease (18/51 cases) with good results in 10/18 cases. We recorded, good results in vasculitis as well, in one girl with focal glomerulosclerosis in transplanted kidney and rapid improvement in all children with Guillaine-Barré Syndrome. PE treatment was effective in metabolic disorders such as tirosynemia and familiar hypercolesterolemia. Only 4/12 patients with acute liver failure due to viral hepatitis recovered. We had poor results in the remaining eight cases. Complications were rare and no viral infection was found in any patient. Our data show that it is possible to use these procedures in pediatric patients even though clinical indications and real effectiveness still need to be cleared up.
Evaluation of Stress on the Autonomic Nervous System of Patients on Mechanical Circulatory Assist
Authors: Tsutsui T. , Jikuya T. , Shigeta O. , Sakakibara Y. , Terada Y. 
Published: March 2018

Purpose The power density values of high (HF; 0.15 to 0.4 Hz) and low frequency (LF; 0.04 to 0.15 Hz) components of arterial pressure were adopted for evaluation of stress on the autonomic nervous system of patients supported by mechanical circulatory assist. Methods Power spectral analysis (PSA) of arterial pressure signals was carried out, and trends in changes in the spectral components were observed in 12 patients on mechanical circulatory support (IABP and/or PCPS) and without the support (n=10). Results The normalized LF was depressed initially and increased gradually in both groups of patients except for four patients on mechanical circulatory assist. Three patients among them consequently died. Conclusions Depressed LF represented marked stress on ANS and prolongation of the depression was related to poor outcome of patients. PSA of systemic blood pressure offers a reasonable tool for evaluation of stress on the ANS and for prediction of the prognosis of patients with circulatory assist devices.
Bidialysis: A new Technique
Authors: Splendiani G. , Zazzaro D. , Tullio T. , Colombo R. , Beciani M. , Violante A. 
Published: March 2018

An increase in solute removal, a shorter dialysis session, the patient's well being and the reduction of global costs are the principal aims of the new hemodialysis methods. The simultaneous use of two hemodialyzers in hemodialysis has been experimented by other researchers. Our technique involves the use of two cuprophan hemodialyzers in sequence (double filter system: DFS), each one connected separately to fresh dialysate. Fifteen symptomatic large patients were treated with DFS and the results were compared to conventional hemodialysis (CHD). After the first hemodialyzer, modification of pH and electrolytes occurred in the plasma composition. In the second hemodialyzer, urea depuration occurred without further significant changes in hydroelectrolytic or acid-basic plasma patterns. The Kt/V increased from 1.10 to 1.29 (18%). The authors conclude that in DFS there was an advantage in urea clearance, osmolarity stability and reduction of side effects.
Oxygen Metabolism under Various bypass flow Conditions during Cardiopulmonary Support in Awake Goats
Authors: Takewa Y. , Tatsumi E. , Taenaka Y. , Takano H. 
Published: March 2018

Despite its wide clinical application, patient recovery from cardiopulmonary support (CPS) is not necessarily satisfactory. To clarify what influence CPS has on organ perfusion, we investigated the oxygen metabolism under various bypass flow (BF) conditions in a series of chronic animal CPS experiments. The CPS system, which consists of a pulsatile ventricular assist device and a compact artificial lung was installed without anesthesia in 6 adult goats weighing 49–51 kg. BF was adjusted stepwise from 0% to 50%, 75%, 90%, and 100% of total systemic blood flow (TSF) by balancing the pulmonary arterial flow. The animals’ TSF and oxygen delivery (DO2) were sufficiently maintained throughout the experiments. The oxygen consumption (VO2) and the oxygen extraction rate (ExO2) increased from 178 ± 14 to 342 ± 19 ml/min, and from 28 ± 2% to 64 ± 1%, respectively, in proportion to the increase of CPBF dependency from 0% to 100%. The blood lactate level did not change appreciably even at 90% BF from 5.7 ± 0.3 to 11.2 ± 1.2 mg/dl, but drastically elevated to 23.5 ± 4.6 mg/dl at the total bypass. This indicates that CPS leads to a relative lack of oxygen and can induce organ dysfunction due to increasing VO2 and ExO2 in proportion to the increase of BF dependence even if TSF and DO2 are sufficiently maintained.
Hemolysis and Hematology Profile during Perfusion: Inter-Species Comparison
Authors: Mueller X. M. , Tevaearai H. T. , Jegger D. , Tucker O. , Von Segesser L.K. 
Published: March 2018

Introduction Cardiopulmonary bypass components need to be tested on an animal model before their clinical application. Because their weight is similar to that of man, the calf and pig are often used. This study compares the impact of prolonged perfusion on hemolysis and hematology profile in both species. Methods Three calves (mean bodyweight: 77.2±4.4 kg) and three pigs (80±5.3 kg) were connected to an extracorporeal circulation circuit by jugular venous and carotid arterial cannulation, with a mean flow rate of 3.5L/min for 6h. After 7 days, the animals were sacrificed. A standard battery of blood samples was taken before, throughout, and 24h, 48h and 7 days after bypass. ANOVA was used for repeated measurements. Results Absolute values of red cell count were higher in the calf (p<0.001), while normalized values were higher in the pig (p<0.001). Absolute values of white cell count were higher in the pig, while normalized values diverged toward the end of the perfusion with an increase in the calf and a decrease in the pig (p<0.001). Free plasma Hb and LDH exhibited similar profiles in both groups. Conclusions In the setting of prolonged perfusion, species type - bovine or porcine - has an impact on hematology profile, but not on hemolytic parameters. These findings should be taken into account when cardiopulmonary bypass components are tested.
Hydrodynamic Function of a Biostable Polyurethane Flexible Heart Valve after Six Months in Sheep
Authors: Wheatley D.J. , Bernacca G.M. , Tolland M.M. , O'connor B. , Fisher J. , Williams D.F. 
Published: March 2018

Survival to six months for sheep with a non-biostable polyurethane mitral heart valve prosthesis has been reported previously, however, with surface degradation and accumulation of calcified fibrin/thrombus that impaired leaflet motion and compromised hydrodynamic function. Newly available biostable polyurethanes may overcome this problem. Six adult sheep with biostable polyurethane trileaflet heart valve prostheses of documented hydrodynamic performance, implanted in the mitral position, were allowed to survive for 6 months. Explanted valves were photographed, resubmitted to hydrodynamic function testing, and studied by light and electron microscopy. Explanted valves were structurally intact and differed little in appearance from their preimplant state. Hydrodynamic testing showed no deterioration in pressure gradient or energy losses compared with pre-implant values. Biostable polyurethanes demonstrated improved blood compatibility leaving leaflets flexible and valve function unimpaired. Biostable polyurethanes may thus improve prospects for prolonged function of synthetic heart valve prostheses.
Characterization of the Distribution of Matter in Hybrid Liver Support Devices where Cells are Cultured in a 3-D Membrane Network or on Flat Substrata
Authors: Catapano G. , Euler M. , Gaylor J.D.S. , Gerlach J. 
Published: March 2018

Bioreactors for liver assist tested on small animal models are generally scaled-up to treat humans by increasing their size to host a given liver cell mass. In this process, liver cell function in different culture devices is often established based on the metabolite concentration difference between the bioreactor inlet and outlet irrespective of how matter distributes in the bioreactor. In this paper, we report our investigation aimed at establishing whether bioreactor design and operating conditions influence the distribution of matter in two bioreactors proposed for liver assist. We investigated a clinical-scale bioreactor where liver cells are cultured around a three-dimensional network of hollow fiber membranes and a laboratory-scale bioreactor with cells adherent on collagen-coated flat substrata. The distribution of matter was characterized under different operating modes and conditions in terms of the bioreactor residence time distribution evaluated by means of tracer experiments and modeled as a cascade of N stirred tanks with the same volume. Under conditions recommended by the manufacturers, matter distributed uniformly in the clinical-scale bioreactor as a result of the intense backmixing (N=1) whereas axial mixing was negligible in the laboratory-scale bioreactor (N=8). Switching from recycle to single-pass operation definitely reduced axial mixing in the clinical-scale bioreactor (N=2). Increasing feed flow rate significantly enhanced axial mixing in the laboratory-scale bioreactor (N=4). The effects of design, operating mode and conditions on matter distribution in bioreactors for liver cell culture suggest that characterization of the distribution of matter is a necessary step in the scale-up of bioreactors for liver assist and when function of liver cells cultured in different bioreactors is evaluated and compared.
The Type II Aachen-Keratoprosthesis in Humans: Case Report of the First Prolonged Application
Authors: Kompa S. , Redbrake C. , Langefeld S. , Brenman K. , Schrage N. 
Published: March 2018

Purpose To improve the prognosis of corneal grafts in silicone-oil filled eyes of patients with severe ocular trauma by a prolonged application of the Type II Aachen-Keratoprosthesis (KPro). This application endeavors to improve post-keratoplasty prognosis by avoiding corneal endothelial dystrophy in the aphakic eye due to contact with silicone oil. Patient and Procedures The Aachen-Keratoprosthesis’ haptic was modified to allow tight contact with cells. The Type II Aachen-Keratoprosthesis was then implanted in an 18-year-old male, with previous management of bilateral corneal rupture. Rather than utilize the device as a temporary intraoperative tool, we extended the device's lifespan in the eye. Main Findings Following implantation, the patient could see hand movements up to 0.1 with best correction. After 8 weeks, vision decreased and a retroprosthetic membrane proliferated. Upon conjunctival retraction, 3 months after the initial surgery, we excised the prosthesis and performed a re-vitrectomy and corneal grafting. The silicone oil was removed. After eighteen postoperative months, the graft remained clear, the retina was completely attached, and the vision was stable: 0.1 best corrected. Conclusion This case reports the prolonged implantation and prospect of the Type II Aachen-Keratoprosthesis to be utilized as a permanent device to restore vision in the near future.
Endothelialization of PTFE vascular grafts under flow induces significant cell changes
Authors: Rademacher A. , Paulitschke M. , Meyer R. , Hetzer R. 
Published: March 2018

Background To minimize thrombogeneity of small diameter PTFE grafts they are usually coated in vitro with endothelial cells under static culture conditions. The disadvantage of this technique is that a cell layer is formed that fails to withstand shear stress typical in normal blood flow. Method Since the in vivo functional and structural status of endothelial cells correlates with the applied shear stress, we developed a computer-controlled perfusion system to seed and culture cells on PTFE-grafts up to a confluent monolayer under the influence of increasing shear stress. The confluence of endothelial coating was defined by immunohistological staining of cross sections, and by upper light microscopy of flattened graft samples. In addition, the expression of fibronectin as an important adhesion molecule was estimated. Results and discussion The application of pulsatile shear stress (6.6 dyn/cm2, 5 min) to grafts endothelialized under perfusion (n = 7) did not lead to a disruption of the confluent cell layer. In contrast, a 5 min long shear stress of 3 dyn/cm2was sufficient to wash more than 50% of cells off the PTFE-graft cultured under static conditions (n = 6). The perfusion cultures showed a significantly higher proliferation rate in comparison with static cultures. This effect was reproducibile in both serum-containing and serum-free culture media. The expression of fibronectin by endothelial cells was significantly higher in the perfused graft compared to the static one. These results suggest the practicability of endothelialized PTFE vascular grafts, preconditioned to shear rates similar to the in vivo situation, as an alternative bypass material in cardiac surgery.