bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitric Oxide Production by Human Peritoneal Mesothelial Cells
Authors: Davenport A. , Fernando R.L. , Robson R. , Varghese Z. 
Published: January 2018

Nitric oxide (NO) has multiple actions, ranging from immunomodulation to regulation of vascular tone and capillary flow. Thus NO generation within the peritoneum could potentially affect peritoneal transport by increasing capillary vasodilatation, and regulate the response to bacterial invasion. Peritoneal mesothelial cells have a common embryological derivation with endothelial cells. As mesothelial cells are the predominant cell type lining the peritoneal cavity, they could potentially be a major source of locally produced nitric oxide. Nitric oxide was measured using the Griess reaction, as total nitrite and nitrate, in fresh unused and spent dialysate effluent (SPDE) from both healthy peritoneal dialysis patients, and during episodes of bacterial peritonitis. Whereas fresh CAPD dialysate was nitrite free (5 ± 0.1 μM), SPDE from a standard 4 h day time exchange contained 10.2 ± 0.6 μM/L/h, and that from the overnight dwell 9.1 ±0.7 μM/L/h. During an episode of peritonitis, dialysate nitrite and nitrate increased significantly from 9.0 ± 1.0 μM/L/h, when not infected to 17.5 ± 2.4, from the first CAPD bag drained at presentation, and 15.2 ± 1.8 for the second and 16.0 ± 2.5 for the third exchange (p<0.01). By the following day nitrite levels had returned to baseline, 7.0 ± 1.0 μM/L/h. Human peritoneal mesothelial cells (HPMC) were cultured and found to produce nitric oxide (261 nmol/mg cell protein), which increased in a dose dependent manner with the addition of spent uninfected CAPD dialysate. The addition of L-arginine, a NO substrate resulted in a 10% increase in nitric oxide production, whereas the addition of the blocker L-NMMA produced a 10% reduction. RNA for inducible nitric oxide synthase (iNOS) was sought using northen blotting technique following combination stimulation with lipopolysaccharide and cytokines (IL-1β, TNFα and γ-INF, and/or spent dialysate from patients with bacterial peritonitis). However, we could not demonstrate RNA production for iNOS. Peritoneal mesothelial cells may be an important source of locally generated nitric oxide within the peritoneal cavity under basal conditions, but as they do not contain iNOS, the markedly increased NO production observed with episodes of acute bacterial peritonitis is more likely due to a combination of increased NO production by peritoneal macrophages and endothelial cells.
Hepatitis E Virus Antibodies in Hemodialysis Patients: An Epidemiological Survey in Central Greece
Authors: Stefanidis I. , Zervou E.K. , Rizos C. , Syrganis C. , Patsidis E. , Kyriakopoulos G. , Sdrakas L. , Tsianas N. , Rigopoulou E.I. , Liakopoulos V. , Dalekos G.N. 
Published: January 2018

Hepatitis E virus (HEV) is the causative agent for enteric non-A, non-B hepatitis. Transmission is mainly via the fecal-oral route but the possibility of an additional parenteric transmission has been raised. Patients undergoing chronic hemodialysis (HD) have an increased risk of exposure to blood transmitted agents. Previous studies concerning prevalence of antibodies to HEV (anti-HEV) among HD patients gave conflicting results. The aim of the study presented here was to determine the prevalence of anti-HEV among HD patients of a well-defined semi-rural region in central Greece (Thessalia region). All patients (n=351, 234 males, mean age 60 ± 14 years) who were being treated in the HD units of central Greece (n=5) during 2001 were tested for anti-HEV antibody. Two commercially available specific solid-phase enzyme-linked immunoassays were applied for anti-HEV detection. Hepatitis B virus markers, antibodies to HCV, HIV and HTLV were also screened in all patients by commercially available assays. Serum aminotransferase (AST, ALT) levels were measured by spectrophotometry. 17 anti-HEV-positive patients were found and prevalence was 4.8%, varying from 1.8 - 9.8% in the various HD units. Prevalence of HBsAg and anti-HCV was 5.7% (2.9 - 15%) and 23.6% (11.5 −36.2%) respectively. The anti-HEV prevalence was increased compared to healthy blood donors in Greece (0.26%, p & 0.01). The highest prevalence of anti-HEV was seen at the HD unit of the General Hospital of Karditsa (9.8%). Risk factors for anti-HEV antibody were not identified: no association was found between anti-HEV positivity and age or sex, duration of HD, hepatitis B or C virus infection markers, previously elevated aminotransferase levels or history of transfusion. Our investigation of HEV infection in the cohort of HD patients in central Greece showed that the prevalence of anti-HEV was greater than in healthy blood donors. There was no association to blood borne infections (HBV, HCV). The high prevalence of anti-HEV we found in one HD unit was probably related to a local infection in the past. However, long-term prospective studies are needed in an attempt to identify whether intra-unit factors are also responsible for the increased prevalence of serologic markers of HEV infection among HD patients.
Temporary Vascular Catheters for Hemodialysis: A 3-Year Prospective Study
Authors: Naumovic R.T. , Jovanovic D.B. , Djukanovic L.J.D. 
Published: January 2018

Background Temporary hemodialysis catheters are necessary in patients with uremia, but complications associated with these catheters represent one of the most important sources of morbidity among ESRD patients. There is no general agreement about the optimal venous access for insertion of a central venous catheter, while risk factors of catheter related complications have not been entirely elucidated. Methods One hundred and seven consecutive patients who required a temporary hemodialysis catheter were prospectively examined. Results. Catheters were placed in 107 consecutive patients (66 right jugular (JC), 41 right femoral (FC)) and maintained in situ for a cumulative total of 2101 days. Early complications (puncture site hemorrhage, hematoma formation, artery puncture) were infrequent, without clinical sequelae. The main late complication was catheter related bacteremia (CRB). There were 16 episodes of CRB (JC-10; FC-6) and Staphylococcus aureus was the most frequently isolated cause of CRB. The mean catheter duration before the onset of CRB was 19.9 and 18.2 days for JC and FC, respectively. Duration of catheter use, and the number of hemodialyses significantly increased the risk for CRB. Actuarial survival for FC was significantly worse than for JC, while Cox proportional hazard models revealed that the femoral site, chronic renal failure and kidney transplantation increased the risk of catheter failure significantly. Conclusion CRB was the most common late complication. Its frequency was similar in JC and FC. The main risk factors for development of CRB were duration of catheter use and the number of performed dialyses. Cumulative hazard of CRB was significantly magnified 3 weeks after insertion for both JC and FC, but actuarial survival with JC was significantly longer.
Mechanical Heart Valve Cavitation: Valve Specific Parameters
Authors: Eichler M.J. , Reul H.M. 
Published: January 2018

Several aspects of mechanical heart valve cavitation, in particular of “severe” vapor cavitation, have been investigated in order to describe the phenomenon of cavitation itself and to classify various mechanical heart valves with respect to their tendency to cavitation. Furthermore, following the results of the measurements, a model for determination of time-dependent physical properties and dynamics of cavitation bubbles, such as size, pressure and temperature was developed. In order to classify the cavitation tendency of mechanical valves, a pulsatile hydraulic-driven circularly mock loop was used. Besides measurements of the relevant hemodynamic parameters, the leaflet velocities of the valves were also determined. In addition, numerous highresolution pressure measurements, in particular the pressure drops necessary for the initiation of cavitation (local atrial pressure drop), were performed. For the investigation of bubble dynamics, a second pulsatile electro-magnetically-driven tester was used. The influence of density, viscosity and temperature of the fluid on the onset of cavitation was investigated. Cavitation events were recorded with a digital high-speed video camera (up to 40,500 frames/sec) for all investigated heart valves and under different conditions. A critical local upstream pressure drop (located within the model atrium after valve closure) of 450 mmHg was found for all valves as well as a valve specific correlation between left ventricular pressure gradient and local upstream pressure drop. Also, a valve dependent correlation between left ventricular pressure gradient and the local upstream pressure drop was provided. Finally, valve specific parameters were found to predict the cavitation tendency for a specific heart valve. The implementation of a suitable theoretical model allowed conclusions on bubble physics. High pressures (up to 800 bar) and temperatures (up to 1,300 °C) at bubble collapse have been determined. The influence of fluid parameters such as density, viscosity and temperature on the onset of cavitation is negligible within physiological range. Critical regions for cavitation for all mechanical heart valves were detected. All mechanical heart valves investigated show cavitation under different conditions (dp/dt) associated with high pressures and temperatures at bubble collapse. Cavitation bubble occurrence depends on valve design and location.
Erythrocyte Metabolism during Renal Anemia Treatment with Recombinant Human Erythropoietin
Authors: DȨbska-Ślizień A. , Owczarzak A. , Łysiak-Szydłowska W. , Rutkowski B. 
Published: January 2018

Recombinant human erythropoietin (epoetin) is widely used for the treatment of renal anemia. The aim of our study was to determine the influence of epoetin on erythrocyte metabolism. Thirty-six hemodialysis patients (22 men, 14 female), aged from 17 to 64 years (mean age 43) and 30 healthy volunteers (12 men, 18 female), aged from 25 to 65 years (mean age 40) were studied. Epoetin (Eprex, Janssen-Cilag) was administered subcutaneously with the starting dose of 2000 IU three times per week for twelve months (range from 75 to 133 IU/kg/week, mean dose 102±21 IU/kg/week). Laboratory markers of: hematological response, iron status and erythrocyte metabolism were measured before epoetin administration. Afterwards the markers were controlled every three months. During epoetin treatment a significant increase in hemoglobin concentration was observed (100% patients responded in a positive way to epoetin). The following changes in erythrocyte metabolism were noticed: 1) in glycolytic enzymes: a significant increase in the activity of hexokinase and that of lactate dehydrogenase, 2) in glycolytic intermediates: a significant increase in the 2,3-diphosphoglycerate and adenosine triphosphate concentrations, 3) a significant increase sodium, potassium adenosine triphosphatase concentration, 4) the glucose uptake by erythrocytes significantly decreased while the lactate production remained stable. During anemia treatment with epoetin in hemodialysis patients not only quantitative but also qualitative changes in erythrocytes were observed.
In Vitro Analysis of Modified Surfaces of Silicone Breast Implants
Authors: Siggelkow W. , Gescher D.M. , Siggelkow A. , Klee D. , Malik E. , Rath W. , Faridi A. 
Published: January 2018

Background Although silicone breast implants are well tolerated, local complications such as capsular contracture occur because of insufficient integration with surrounding tissues. In this study, cell behaviour on hydrophilized silicone breast implant foils was analysed qualitatively and quantitatively under in vitro conditions in order to provoke the desired responses in a defined environment. Methods Silicone breast implant foils with different surface modifications were tested after 24 hours, 5 days and 7 days. The following modifications of silicone implant foils were tested: Unmodified silicone, silicone after-graft polymerisation for polyacrylic acid (pAAc), silicone-pAAc-fibronectin adsorptive, silicone-pAAC-fibronectin covalent, positive and negative controls. Experiments were conducted using cell culture with murine mouse fibroblasts L-929. Cytotoxicity assays were carried out in direct and indirect contact with cells grown on the material. For the viability test and qualitative analysis of cell proliferation on different foils, both fluoresceine-diacetate and ethidiumbromide were used and in addition the morphologic description of hemalaun-stained cells were used. Quantitative cell analysis was carried out using XTT after resuspension. Results Toxic influence on cell cultures could be excluded for coated and uncoated surfaces in contact with dissolved biomaterials. Unmodified silicone surfaces showed poor cell growth in direct contact. We found a gradual improvement of cell morphology, with the spread and proliferation depending on the type of surface modification. Better results were achieved with covalently coupled fibronectin and GRGDS than with pAAc. Conclusion Covalent immobilisation of hydrophobic silicone rubber can improve the initial cellbiomaterial interactions that are required to aid the successful development of tissue-like structures.
Effect of Valsartan versus Lisinopril on Peritoneal Sclerosis in Rats
Authors: Duman S. , ŞEn S. , Duman C. , Oreopoulos D.G. 
Published: January 2018

Background Peritoneal sclerosis (PS) is one of the most serious causes of failure in long-term peritoneal dialysis. Angiotensin II is known to promote fibrosis and inflammation in various tissues. We previously showed that ACE inhibitors (ACEIs) have beneficial effects on hypertonic PD solutions (3.86% PD) induced peritoneal alterations. The aim of this study is to compare the effects of an ACEI and a receptor blocker on peritoneal alterations induced by hypertonic PD solutions in rats. Methods Forty-three non-uremic rats were divided into four groups: group I (Sham) rats received no treatment (n=11), group II received hypertonic (3.86%, 10 ml/day) PD solution (n=10) and groups III and IV received hypertonic PD solution (10 ml/day) plus 640 mg/L valsartan (n=11) and 100 mg/L lisinopril in drinking water (n=11). After four weeks, a one-hour peritoneal equilibration test (PET) was performed with 3.86% PD solution. Dialysate-to-plasma urea ratio (D/P urea), glucose reabsorption (D1/D0 glucose), ultrafiltration volume (UF), dialysate protein, TGFß1 and VEGF levels were determined. Results Administration of valsartan or lisinopril resulted in preserved UF (8±0.8 and 6.7±0.7 vs 4.9±0.8 mL), D1/D0 glucose (0.69±0.05 and 0.62±0.05 vs 0.56±0.04) and peritoneal thickness (19.4±2.9 and 28.5±5.2 vs 53±3 μm), respectively. Both higher level of TGF ß1 (206±40 vs 474±120 pg/mL, p<0.05), and VEGF in dialysate effluent (4±0.4 vs 7.9±3 pg/mL, p>0.05), was determined in the dextrose group. Both cytokines are partially inhibited by valsartan or lisinopril (p >0.05) Conclusion Exposure to hypertonic glucose solution resulted in alterations in peritoneal transport manifested by a rapid dissipation of the glucose gradient and resultant impaired UF response. Administration of valsartan or lisinopril led to attenuation of these alterations. We suggest that the equal protection of the peritoneal membrane from the effects of hypertonic glucose was achieved by receptor blockers and ACE inhibitors.
Experimental Evaluation of Transport Force in the Rabbit Ureter
Authors: Di Paolo N. , Sacchi G. , Gentile F. , Lombardi M. , Sansoni E. , Gaggiotti E. 
Published: January 2018

Background Cleaning the urinary tract by so-called “wash-out effect” and promoting high diuresis has long been advocated but has had very little scientific backing and few prospective studies in international journals. Aim To verify whether the physical laws describing the transport force of water in rivers and pipes are also valid for urinary outflow. Methods A laboratory model for measuring transport force, given liquid and solid capacity, was adapted to create an in vivo model based on the rabbit urinary tract. Results Fluid flow in the rabbit renal pelvis and ureters was found similar to flow in pipes, obeying the physical laws of water transport to some extent. When the quantity of liquid flowing in the urinary tract in unit time was doubled, the transport force increased by various orders of magnitude. When the liquid increased by a larger factor, the transport force became enormous. Conclusions The results confirm the utility of maintaining high diuresis in patients with renal calculus, but stress the utility of drinking 1–2 liters of hypotonic water in a short time to obtain an enormous increase in transport force which increases the probability of a cleansing effect.
Facial Changes in Adult Uremic Patients on Chronic Dialysis: Possible Role of Hyperparathyroidism
Authors: Ferrario V.F. , Sforza C. , Dellavia C. , Galassi A. , Rey L. Rocca , Chiarelli G. , Cozzolino M. , Gallieni M. , Brancaccio D. 
Published: January 2018

Background Uremic patients on regular dialytic treatment (RDT) are often affected by a complex metabolic syndrome leading to osteodystrophy. Bone changes are primarily due to high bone turn over, often combined with a mineralization defect leading to increased bone fractures and bone deformities. Although rarely considered, the craniofacial skeleton represents one of the peculiar targets of this complex metabolic disease whose more dramatic pattern is a form of leontiasis ossea. This complication, although described, has never been evaluated in depth nor quantitatively assessed. In order to assess facial deformities in uremic conditions and to understand the possible relation with hyperparathyroidism, we undertook a quantitative evaluation of soft facial structures in a cohort of uremic patients undergoing RDT. Methods The three-dimensional coordinates of 50 soft-tissue facial landmarks were obtained by an electromagnetic digitizer in 10 male and 10 female patients with chronic renal insufficiency aged 53–81 years, and in 34 healthy individuals of the same age, ethnicity and sex. Uremic patients were enrolled according to hyperparathyroid status (PTH < 300 pg/mL and PTH > 500 pg/mL). From the landmarks, facial distances, angles and volumes were calculated according to a geometrical face model. Results Overall, the uremic patients had significantly larger facial volumes than the reference subjects. The effect was particularly evident in the facial middle third (maxilla), leading to an inversion of the mandibular-maxillary ratio. Facial dimensions were increased in all three spatial directions: width (skull base, mandible, nose), length (nose, mandible), and depth (mid face, mandible). The larger maxilla was accompanied by a tendency to more prominent lips (reduced interlabial angle). Some of the facial modifications (nose, lips, mandible) were significantly related to the clinical characteristics of the patients (age, duration of renal insufficiency and PTH levels). Conclusions This report, the first in the literature, shows that facial structures of uremic patients are enlarged in comparison with matched normal subjects and that increased bone turnover could be responsible – at least in part – for facial bone changes.
PPS-PEG Surface Coating to Reduce Thrombogenicity of Small Diameter ePTFE Vascular Grafts
Authors: Karrer L. , Duwe J. , Zisch A.H. , Khabiri E. , Cikirikcioglu M. , Napoli A. , Goessl A. , Schaffner T. , Hess O.M. , Carrel T. , Kalangos A. , Hubbell J.A. , Walpoth B.H. 
Published: January 2018

Aims Patency failure of small vascular synthetic grafts is still a major problem for coronary and peripheral revascularization. Thus, three new surface coatings of small synthetic grafts were tested in an acute pig model to evaluate their thrombogenicity (extracorporeal arterio-venous shunt) and in a chronic rat model to evaluate the tissue reaction they induced (subcutaneous implantation). Methods In five domestic pigs (25–30 kg) an extracorporeal femoro-femoral arterio-venous shunt model was used. The study protocol included first a non-heparinized perfusion sequence followed by graft perfusion after 10,000 UI iv heparin. Grafts were perfused for 3 and 9 minutes. The following coatings were tested on ePTFE grafts: poly-propylene sulphide (PPS) – poly-ethylene glycol (PEG) (wet and dry applications) as well as carbon. Two sets of control were used, one dry and one wet (vehicle only). After perfusion grafts were examined by scanning electron microscopy for semiquantitative assessment (score 0–3) of cellular and microthrombi deposition. To assess tissue compatibility, pieces of each material were implanted subcutaneously in 16 Wistar rats. At 2, 4, 8, 12 weeks four animals each were sacrificed for semi-quantitative (score 0–3) histologic evaluation of tissue reaction. Results In the pig model, cellular deposition and microthrombi formation increased over time. In non-heparinized animals, the coatings did not improve the surface characteristics, since they did not prevent microthrombi formation and cellular deposition. In heparinized animals, thrombogenicity was lowest in coated grafts, especially in PPS–PEG dry (P&0.05), and highest in controls. Cell deposition was lowest in PPS–PEG dry, but this difference was not statistically significant vs. controls. In the rat model, no significant differences of the tissue reaction could be shown between materials. Conclusion While all coatings failed to add any benefit for lowering tissue reaction, surface coating with PPS–PEG (dry application) reduced thrombogenicity significantly (in heparinized animals) and thus appears to be promising for improving graft patency of small synthetic vascular prostheses.
Implant Infection and Infection Resistant Materials: A Mini Review
Authors: Arciola C.R. , Alvi F.I. , An Y.H. , Campoccia D. , Montanaro L. 
Published: January 2018

Implant infection is an aggressive, often irreducible post-surgical infection. It remains the primary cause of implant failure. Bacterial contamination during surgery and subsequent adhesion onto biomaterial surface of opportunistic microorganisms, such as staphylococcal species, exopolysaccharidic slimes or specific adhesins, initiates the implant infection. Pathogenesis of periprosthestic infection is the focus of studies aimed at developing infection resistant materials.