bluuebunny/crossref_metadata_2025_split huggingface dataset:
Advanced Glycation end Products: Specific Fluorescence Changes of Pentosidine-Like Compounds during Short Daily Hemodialysis
Authors: Fagugli R.M. , Vanholder R. , De Smet R. , Selvi A. , Antolini F. , Lameire N. , Floridi A. , Buoncristiani U. 
Published: March 2018

Background Advanced glycation end products (AGE) accumulate in uremia and represent an important etiopathogenetic cause of morbidity in dialyzed patients. Conventional hemodialysis treatment seems to be ineffective in lowering AGE levels. We wished to investigate whether daily hemodialysis (DHD), a treatment that seems to result in better clinical condition in end-stage renal disease patients, is effective in the reduction of these compounds. Methods We evaluated 10 non-diabetic patients on standard hemodialysis (SHD = 3 × 4h/week) for more than 6 months by a crossover study. These patients were assigned randomly to 6 months of DHD (6 × 2h/week) or 6 months of SHD. Then, they were switched to 6 months of the alternative treatment. At the end of these two periods, we studied pentosidine-like AGE compounds by measuring the total fluorescence at a wavelength characteristic for these substances: Ex: 335nm / Em:385nm; we also measured protein-linked pentosidine at the same time points. Finally, we determined the AGE-related total fluorescence in the deproteinized serum of 13 uremic patients on peritoneal dialysis (CAPD) and of 10 healthy controls. Results Pre-HD AGE-related total fluorescence obtained after 6 months of DHD was significantly lower than that obtained with standard HD (DHD = 201.3 ± 36.4 AU/ml vs. SHD = 267.5 ± 141.4 AU/ml, p=0.03). The extraction rate per minute of dialysis was slightly, but not significantly higher during DHD than SHD (0.29 ± 0.11% vs. 0.23 ± 0.04, p = 0.07). AGE-related total fluorescence pre-HD values in patients treated by SHD and DHD were about 20-fold higher than in control subjects. They did not differ from CAPD patients. The pre-dialysis level of protein-linked pentosidine was significantly lower in DHD than in SHD (DHD = 16.12 ± 4.71 pmol/mg protein, SHD = 22.64 ± 6.86 pmol/mg protein, p < 0.01). Conclusions DHD showed a reduction in AGE-related total fluorescence, although the mean value remained higher than in control subjects. DHD is also accompanied by a decrease in protein-linked pentosidine.
Influence of ischemic time and temperature on endothelial cell growth after transport
Authors: Dohmen P.M. , Meuris B. , Flameng W. , Konertz W. 
Published: March 2018

Background The preparation of tissue-engineered material is a complex procedure. The possibility to transport tissue between laboratories without loosing endothelial cell (EC) function was examined. Methods In 3 month old juvenile sheep (n=6) a piece of vein (n = 14) was harvested and transported over 900 km to the tissue laboratory in Dulbecco's Modified Eagle's Medium (=DMEM). Vein material of each animal was transported at 4°C (Group I, n = 6) and 25°C (Group II, n = 8). EC growth potential was evaluated in function of the medium temperature and the ischemic time (between 8–24 hours). At the end of the first passage the EC of Group I and II were put together to save autologous serum of the sheep. After the 2nd passage the EC were cryopreserved at −80°C to evaluate if EC viability would change. Results The growth potential of hypothermic Group I was equal in 16.7% (n = 1), higher in 33.3% (n = 2) and lower in 50% (n = 3) than Group II which had the same ischemic time during transport. Increase in ischemic time up to 24 hours showed no decrease of growth potential. Cryopreservation had no significant influence on EC viability. Viability at the end of the second passage, after recultivation and at the end of the third passage was 97.4% ± 1.52, 95.5%±1.34 and 94.5% ± 1.08 respectively. Conclusions In sheep there is no need to transport the EC at a temperature of 4°C. Up to 24 hours growth potential and viability are maintained also at 25°C.
Mono and Bi-ventricular Assistance: Their Effect on Ventricular Energetics
Authors: Ferrari G. , Górczyńska K. , Mimmo R. , De Lazzari C. , Clemente F. , Tosti G. , Guaragno M. 
Published: March 2018

When mono- and bi-ventricular mechanical assistance is used for heart recovery, its control strategy and circulatory variables affect ventricular energetics (external work-EW, oxygen consumption-VO2, cardiac mechanical efficiency-CME). This study is based on the data obtained in vitro and presents an analysis of the effects of the mono- and bi-ventricular mechanical assistance on ventricular energetics. The assistance was conducted on the principle of counterpulsation with atrio-arterial connection. It includes the following stages: 1) the characterisation of the isolated ventricle model in terms of EW, VO2 and CME as a function of the filling pressure and peripheral resistance, 2) modelling of left ventricular and pulmonary dysfunction, followed by left ventricular and bi-ventricular assistance. Experimental data enable us to draw the following conclusions: • in general, the greatest hemodynamic improvement does not correspond to the highest energetic improvement, • LVAD assistance deteriorates left ventricular CME while its effect on right ventricular energetics depends on the value of right ventricular elastance (Emax). Right ventricular CME is deteriorated by BVAD assistance irrespective of right Emax, • the energetics optimisation in bi-ventricular assistance is closely related to the right Emax, which could probably be a deciding factor in the choice of the assistance mode.
Influence of Recombinant Human Erythropoietin Therapy on Plasma Endothelin-1 Levels during Hemodialysis
Authors: Stefanidis I. , Mertens P.R. , Wurth P. , Bach R. , Makropoulos W. , Mann H. , Heintz B. 
Published: March 2018

The correction of anemia with human recombinant erythropoietin (rHuEPO) in end stage renal disease is associated with hypertension in about one third of hemodialysis patients. The pathogenesis of the rHuEPO-induced hypertension is still uncertain, though evidence of the involvement of endothelial cells has emerged. The aim of this study was to determine plasma endothelin-1 during hemodialysis and to compare the endothelin-1 levels in hemodialysis patients with and without rHuEPO substitution. Nineteen stable patients (13 male and 6 female, mean age 62 ± 11 years) with end stage renal disease were studied. Cuprophan dialysers (GFS 12®, Gambro, Lund, Sweden) were used for hemodialysis in all cases. rHuEPO (40U/kg s.c.) was administered to 10 patients. Blood pressure (BP; RR mmHg) and blood volume changes (ΔBV; hemoglobinometry %) were serially measured. Samples were taken before and every hour during hemodialysis. Plasma endothelin-1 was measured by ELISA (R&D Systems, Minneapolis, USA) and corrected for hemoconcentration. Endothelin-1 concentration was elevated before commencement of hemodialysis (1.16 ± 0.36 pg/ml) when compared to healthy controls (ref. 0.3 - 0.9) and increased to 1.47 ± 0.51 pg/ml by the end of the session (p<0.05). In patients under rHuEPO-substitution plasma endothelin-1 was higher when compared to patients without substitution before (1.25 ± 0.3 vs. 1.05 ± 0.3 pg/ml) and at the end of HD (1.62 ± 0.5 vs. 1.28 ± 0.3 pg/ml, p<0.05). There was no difference in BP and ΔBV between the two groups during treatment. Plasma endothelin-1 was higher in hemodialysis patients and there was a continuous rise in plasma endothelin-1 during a session. Comparison of two groups of hemodialysis patients with and without s.c. rHuEPO-replacement treatment revealed a significantly higher plasma endothelin-1 concentration in patients with s.c. rHuEPO treatment. However, the elevated endothelin-1 levels were not accompanied by arterial hypertension.
Cuffed-tunneled Femoral Catheter for Long-term Hemodialysis
Authors: Chow K.M. , Szeto C.C. , Leung C.B. , Wong T. Y.H. , Li P.K.T. 
Published: March 2018

Background Hemodialysis access is a challenging problem in patients with exhausted dialysis access sites of their upper extremities. Femoral arterio-venous polytetrafluoroethylene (PTFE) graft is often necessary. The safety and efficacy of cuffed tunneled catheters at the femoral site for long-term hemodialysis has not been extensively studied. Methods We inserted 14 cuffed-tunneled femoral catheters in 11 hemodialysis patients with exhausted dialysis access sites of their upper extremities. Access survival and risk of infection were compared with the 11 femoral PTFE grafts in 10 patients of our center during the same period. The choice of dialysis access was determined by the individual nephrologist. Access survival was defined as the achievement of a blood flow rate of at least 180 ml/min. Results The median survival of tunneled femoral catheter and PTFE graft were 166 days and 560 days respectively (log-rank test, p = 0.33). Seven of the 14 tunneled femoral catheter remained in use 3 months after insertion. The incidence of catheter- or graft-related infection was 0.38 and 0.23 episodes per 100 catheter / graft days for tunneled femoral catheters and PTFE graft respectively (p = 0.6). Five tunneled catheters and one PTFE graft had to be removed because of infection. Blood flow rates achieved were comparable between tunneled femoral catheter and PTFE graft. Conclusions Our preliminary data suggest that the cuffed tunneled femoral catheter has reasonable access survival and an acceptable risk of infection. It may provide a safe and effective access for long-term hemodialysis patients with exhausted access in their upper extremities, especially high risk patients who are not suitable for femoral PTFE graft creation.
A Hybrid (Numerical-physical) Model of the Left Ventricle
Authors: Ferrari G. , Kozarski M. , De Lazzari C. , Clemente F. , Merolli M. , Tosti G. , Guaragno M. , Mimmo R. , Ambrosi D. , Głapinski J. 
Published: March 2018

Hydraulic models of the circulation are used to test mechanical devices and for training and research purposes; when compared to numerical models, however, they are not flexible enough and rather expensive. The solution proposed here is to merge the characteristics and the flexibility of numerical models with the functions of physical models. The result is a hybrid model with numerical and physical sections connected by an electro-hydraulic interface - which is to some extent the main problem since the numerical model can be easily changed or modified. The concept of hybrid model is applied to the representation of ventricular function by a variable elastance numerical model. This prototype is an open loop circuit and the physical section is built out of a reservoir (atrium) and a modified windkessel (arterial tree). The corresponding equations are solved numerically using the variables (atrial and arterial pressures) coming from the physical circuit. Ventricular output flow is the computed variable and is sent to a servo amplifier connected to a DC motor-gear pump system. The gear pump, behaving roughly as a flow source, is the interface to the physical circuit. Results obtained under different hemodynamic conditions demonstrate the behaviour of the ventricular model on the pressure-volume plane and the time course of output flow and arterial pressure.
Effect of Low Molecular Weight Heparin on Bone Metabolism and Hyperlipidemia in Patients on Maintenance Hemodialysis
Authors: Lai K.N. , Ho K. , Cheung R.C.K. , Lit L.C.W. , Lee S.K.M. , Fung K.S. , Tong M.K.L. , Lam C.W.K. 
Published: March 2018

The effect of low molecular weight heparin (LMWH) on serum lipid profile in hemodialysis remains controversial and its effect on bone metabolism has not been studied. A crossover study was conducted in 40 patients on stable hemodialysis using unfractionated heparin (UFH) for more than 24 months. These patients were then treated with a LMWH (nadroparin-Ca) for 8 months during hemodialysis and subsequently switched back to UFH for 12 months. Serum lipid profile, biochemical markers for bone metabolism, and bone densitometry (BMD) were monitored at four-month intervals while all medications remained unchanged. Cholesterol (TC), triglyceride (TG), low-density lipoprotein-cholesterol (LDL-C), lipoprotein(a) (Lp(a)), apolipoprotein B (Apo B) were raised in 35%, 29%, 12%, 24% and 24% of patients respectively. High-density lipoprotein-cholesterol (HDL-C) and apolipoprotein A1 (Apo A-1) were reduced in 47% and 9% of patients. Bone-specific alkaline phosphatase (BALP) and intact osteocalcin (OSC), both reflecting osteoblastic activity, were raised in 65% and 94% of patients. Tartrate-resistant acid phosphatase (TRACP) reflecting osteoclastic activity and parathyroid hormone (PTH) were elevated in 35% and 88% of patients. Following LMWH treatment, TC, Tg, Lp(a) and Apo B were reduced by 7%, 30%, 21% and 10% respectively (p<0.05 or <0.01) while Apo A-1 were raised by 7% (p<0.01). Simultaneously, TRACP was reduced by 13% (p<0.05). These biochemical changes were detected soon after 4 months of LMWH administration. Although BMD values in our patients were lower than those of age-matched normal subjects, significant changes were not observed with LMWH treatment. After switching back to UFH for hemodialysis, these biochemical indices reverted to previous values during UFH treatment with a significant higher level in TC and Apo B while serum Apo A-1 remained elevated. Our study suggests LMWH may partially alleviate hyperlipidemia and, perhaps, osteoporosis associated with UFH administration in patients on maintenance hemodialysis.
Heparin Coating of the Extracorporeal Circuit Combined with Leukocyte Filtration Reduces Coagulation Activity, Blood Loss and Blood Product Substitution
Authors: Martens S. , Matheis G. , Wimmer-Greinecker G. , Feuerbach J. , Jakob A. , Mierdl S. , Moritz A. 
Published: March 2018

Background Cardiopulmonary bypass is associated with activation of the coagulation cascade. Occasionally, this results in postoperative hemorrhage and consequently the need for blood products associated with increasing costs and risk of infection. Contact activation of the intrinsic coagulation pathway, and damage to cellular blood components with the release of proteolytic substances from neutrophil granulocytes have been linked to these coagulation disorders. Methods Eighteen routine CABG-patients were randomly assigned to totally heparin coated circuits (Bioline coating) combined with leukocyte filtration in a double blind protocol (group I), 34 patients served as controls (group II). Leukocyte filters were activated before release of the aortic crossclamp. Coagulation activity, postoperative blood loss, and substitution with blood products were assessed. Results Blood loss in the first 24h after surgery was significantly lower with combined application of heparin coating and leukocyte filters (group I) vs. controls (group II) (526±78ml vs. 786±88ml; p<0.05). Thrombin formation represented by prothrombin fragments 1+2 was significantly lower in group I vs. group II after declamping of the aorta (2.1±0.3nmol/L vs. 4.0±0.3nmol/L; p<0.05). Group I showed higher AT III plasma than group II (48.8±3.2% vs. 41.5±1.7%; p<0.05). Conclusions Leukocyte filtration during reperfusion in heparin coated cardiopulmonary bypass circuits is associated with lower coagulation activation, decreased blood loss and reduced transfusion of packed red cells in elective CABG patients.
Potassium-Based Dilutional Method to Measure Hemodialysis access Recirculation
Authors: Brancaccio D. , Tessitore N. , Carpani P. , Gammaro L. , Losi B. , Zoni U. , Maschio G. , Gallieni M. 
Published: March 2018

Background Assessment of access recirculation (AR) is crucial to dialysis efficiency and there is thus a need for a method yielding a highly accurate, fast, easy and economical measurement that can be applied in any busy dialysis clinic. Non-urea based dilutional methods are more accurate than urea based methods and avoid problems with cardiopulmonary recirculation, but they require expensive specialized devices, which limit their applicability. Methods We developed a simple dilutional method of AR which does not require any specific device, based on the determination of serum potassium [K+] in two samples. Briefly, a basal sample is drawn at the time of needle insertion (basal [K+]); needles are connected to blood lines and blood flow rate is quickly increased to 300 ml/mm; a second sample (arterial [K+]) is drawn from the arterial line port within 5 to 10 seconds, to avoid errors due to cardiopulmonary recirculation of the normal saline entering the blood stream. At this time, if recirculation is present, part of the normal saline will enter the arterial line and dilute the serum [K+]. The AR formula is: AR (%) = 100 x [1 - arterial K+ / basal K+] We compared our method with the two-needle urea and ultrasound velocity dilution methods. Results: AR values by the ultrasound method > 10% were hypothesized as gold standard for AR, against which values obtained with the potassium method were compared. The potassium based method showed: sensitivity (100%,); specificity (95%); predictive value, positive (91%); predictive value, negative (100%). In addition, the potassium based method appears to be more reliable than the two-needle urea based method. Conclusion Our method, similar to other dilutional methods, is not influenced by cardiopulmonary recirculation or veno-venous disequilibrium and is fast and accurate. Moreover it is very simple, economical, and can easily be performed in any dialysis unit.
Tissue-Engineered Heart Valve Leaflets: An Animal Study
Authors: Kim W.G. , Cho S.K. , Kang M-C. , Lee T-Y. , Park J.K. 
Published: March 2018

Background Tissue-engineered heart valve leaflets are a promising way to overcome the inherent limitations of current prosthetic valves. The aim of this study was to compare the biological responses of an autologous cell seeded scaffold and an acellular scaffold implanted in the pulmonary valve leaflet in the same animal. Methods Myofibroblasts and endothelial cells were isolated and cultured from an ovine artery. A synthetic biodegradable scaffold consisting of polyglycolic acid and polylactic acid was initially seeded with the myofibroblasts, then coated with endothelial cells. Cells were seeded using a medium containing collagen and cultured. A tissue-engineered construct and a plain scaffold were implanted as double pulmonary valve leaflet replacement in the same animal in an ovine model (n=3). Additionally, the tissue-engineered construct (n=2) and the plain scaffold (n=2) were implanted as single valve leaflet replacements for long-term analysis. After sacrifice, the implanted valve leaflet tissues were retrieved, analyzed visually and using light microscopy. Results Three animals that underwent replacement of two valve leaflets with a tissue-engineered construct and a plain scaffold, survived only a short-time (12, 24, 36 hours). The death was attributed to heart failure caused by severe pulmonary insufficiency. Animals that underwent single valve leaflet replacement survived longer and were electively sacrificed at 6 and 9 weeks after operation. The analysis of the leaflets from the short-term survivors showed that the tissue-engineered constructs contained less fibrins and protein exudates than the plain scaffold. In contrast, leaflets obtained from animals surviving 6 and 9 weeks showed similar well organized granulation tissues in the tissue-engineered constructs and the plain scaffolds. Conclusion This animal experiment demonstrates that in the early phase of implantation, the tissue-engineered construct shows a better biological response in terms of antithrombogenicity than the plain scaffold, although both of them have similar results in the later reparative phase.
Flow Analysis in Vascular Shunts that Bypass the Carotid Artery
Authors: Verkerke G.J. , Van Den Dungen J.J.A.M. , Meyer T. , Rakhorst G. 
Published: March 2018

When blood flow through a carotid artery is impaired and vascular surgery is necessary to restore adequate circulation a vascular shunt can be applied to maintain cerebral blood flow. Several vascular shunts are commercially available, but there is only limited test data on their flow capacity. The purpose of this study is to determine the flow capacity of three vascular shunt systems. A theoretical model has been developed for this purpose. To validate the model, in vitro flow measurements were taken. Application of the model showed that all shunts cause a decrease in blood flow. The amount of flow decrease varied widely from 13% (Javid shunt) to 55% (Pruitt-Inahara). In vitro measurements confirmed the validity of the model. In conclusion, it is important for the vascular surgeon to realise that vascular shunts show large differences in flow capacity. Of the three investigated shunts, the Javid has the highest flow capacity.
Surface Topography and Surface Elemental Composition Analysis of Helixone®, a New High-Flux Polysulfone Dialysis Membrane
Authors: Bowry S.K. , Ronco C. 
Published: March 2018

Modern dialysis membranes need to fulfil two basic requirements. Firstly, the membrane structure, defined in terms of the size, structure and distribution of the pores at the inner separating layer of the membrane must be such that uraemic solutes of a defined molecular-weight range are selectively removed. Secondly, the physical and chemical properties of the blood-contacting surface must be such that minimal blood-material interactions take place that could either affect the functioning of the membrane, or, cause adverse reactions for the patient. A new polysulfone dialysis membrane, Helixone®, has been developed specifically for the elimination of larger uraemic toxins using convective therapy modalities such as haemodiafiltration. The membrane is characterised by the nanoscale modulation of the innermost surface structures that lead to significantly increased sieving coefficients for molecules such as β2-microglobulin, while maintaining the extremely low albumin removal property of the high-flux Fresenius Polysulfone® membrane. A recent publication (Ronco C, Bowry SK. Nanoscale modulation of the pore dimensions, size distribution and structure of a new polysulfone-based high-flux dialysis membrane. Int J Artif Organs 2001; 24: 726–35) described the characterisation of the membrane of Helixone® in terms of the membrane wall structure- and permeation-related parameters. In this paper, we describe the analysis of membrane surface parameters that influence the biocompatibility as well as the functioning of a membrane. The degree of roughness and the type of chemical groups of a blood-contacting surface are two of the main determinants of the biocompatibility characteristics of a membrane. The surface elemental composition of Helixone® was determined using electron spectroscopy for elemental analysis (ESCA) while the surface topography of the membrane was evaluated using atomic force microscopy (AFM). The analysis showed that Helixone® has an improved, smoother blood-contacting surface and retains the essential surface chemistry, and therefore the acknowledged biocompatibility profile, of the Fresenius Polysulfone® membrane.