bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pharmacokinetics of Intraperitoneal Cefazolin and Ceftazidime Coadministered to CAPD Patients
Authors: Elwell R.J. , Manley H.J. , Frye R.F. , Bailie G.R. 
Published: January 2018

Purpose Guidelines for empiric treatment of PD-related peritonitis published in 2000 recommend concurrent intraperitoneal (IP) cefazolin and ceftazidime. The pharmacokinetics (PK) of these agents combined have not been studied. This study was designed to determine the PK of combined IP cefazolin and ceftazidime in CAPD patients. Design Prospective PK study in seven non-infected CAPD patients. Procedures Patients had a peritoneal equilibration test (PET), then received one IP dose of cefazolin and ceftazidime (15 mg/kg each) co-administered over a 4-hour dwell, then performed three CAPD exchanges over the next 16 hours. Serum and dialysate samples collected over the 20-hour study period were assayed for drug concentrations by HPLC. Outcome measures PK parameters. Statistical methods Correlations were tested between PET and PK parameters using the Pearson-product correlation coefficient. Main findings Serum cefazolin and ceftazidime levels exceeded the minimum inhibitory concentrations for susceptible organisms (8 mg/L) throughout the 20 hour study period. Mean cefazolin and ceftazidime PK parameters included: bioavailability, 71% and 63%; elimination rate constant, 0.031 and 0.045 h−1; total clearance, 5.8 and 16.0 ml/min; peritoneal clearance, 1.6 and 3.9 ml/min; renal clearance, 2.3 and 3.9 ml/min, respectively. Predictive equations suggest that 1000 mg IP of cefazolin and of ceftazidime every 24 hours would produce average steady-state trough serum cefazolin and ceftazidime concentrations of 70 ± 52 mg/L and 17 ± 7 mg/L, respectively. There was no correlation between PET and PK parameters. Conclusions Co-administration did not adversely affect the PK of either agent. IP cefazolin and ceftazidime (15 mg/kg) produced adequate serum and dialysate concentrations in CAPD patients for 20 hours. PK predictions suggest that most patients would achieve adequate cefazolin and ceftazidime concentrations with 1000 mg IP once-daily. Anuric patients and those with significant residual renal function may require a more individualized approach.
Hypertriglyceridemia: Apheretic Treatment
Authors: Giannini G. , Valbonesi M. , Morelli F. , Carlier P. , De Luigi M.C. , Dejana A.M. , Ruzzenenti M.R. 
Published: January 2018

Patients with extremely high triglyceride levels and associated lipemia are at high risk for acute pancreatitis. Two factors can increase triglyceride-rich lipoproteins; one is overproduction and other is a defect in clearance. Either mechanism can cause hypertriglyceridemia and both may exist simultaneously. Causes can be either primary or secondary. Plasmapheresis is efficacious for severe hypertryceridemia in patients who have not responded to previous therapies. We have treated 15 cases of hypertrygliceridemia complicating the course of patients receiving Cyclosporin A after bone marrow transplantation. Five patients were treated with plasmapheresis, the other ten with cascade filtration. The removal rate for triglycerides was 58.0% for patients treated by cascade filtration and 63.5% for patients treated by plasmapheresis. The removal rates for triglycerides were low possibly as a consequence of early saturation of the filter.
Pathogenesis of Implant Infections by Enterococci
Authors: Baldassarri L. , Creti R. , Montanaro L. , Orefici G. , Arciola C.R. 
Published: January 2018

Enterococci are commensals of human and animal intestinal tract that have emerged in the last decades as a major cause of nosocomial infections of bloodstream, urinary tract and in infected surgical sites. Enterococcus faecalis is responsible for ca. 80% of all enterococcal infections while Enterococcus faecium accounts for most of the others; among the most relevant risk factors for development of enterococcal infections is the presence of implanted devices. The pathogenesis of such infections is poorly understood, but several virulence factors have been proposed. Among them, the ability to form biofilm has recently been shown to be one of the most prominent features of this microorganism, allowing colonization of inert and biological surfaces, while protecting against antimicrobial substances, and mediating adhesion and invasion of host cells and survival within professional phagocytes. Biofilm formation has been shown to be particularly important in the development of prosthetic valve enterococcal endocarditis and stent occlusion. Enterococci are also able to express other surface factors that may support colonization of both inert and biological surfaces, and that may be involved in the invasion of, and survival within, the host cell.
Factors Affecting Microbial Adhesion to Stainless Steel and Other Materials Used in Medical Devices
Authors: Verran J. , Whitehead K. 
Published: January 2018

The role of biofilm in medical device associated infections is well documented. Biofilms are more resistant to antibiotics than planktonic cells, these are extremely difficult to treat. Prevention strategies include efforts to insert implants under stringent aseptic conditions, and also encompass the development of novel materials which interfere with the initial attachment of microorganisms to the surface of the device. Microbial cells also attach onto hygienic surfaces in the hospital setting, and thereby pose a cross-infection problem. In this case, vigorous cleaning and sanitizing regimes may be employed in addition to any surface modifications. Many factors affect the initial attachment of organisms to inert substrata, and their subsequent retention or removal/detachment, including the physical and chemical nature and location of the substratum, the type of organic material and microorganisms potentially fouling the surface, and the nature of the interface (solid-liquid in the body; solid-air on environmental surfaces). Focusing on one factor, surface topography, it is apparent that many further variables need to be defined in order to fully understand the interactions occurring between the cell and surface. It is therefore important when modifying one substratum surface property in order to reduce adhesion, to also consider other potentially confounding factors.
Hospitalization in Hemodialysis Patients in One Region of Lithuania
Authors: Vaičiūnienė R. , Kuzminskis V. , Bumblytė I.A. 
Published: January 2018

Introduction and Methods The objective of our study was to evaluate hospitalization rates in hemodialysis patients in the region of Kaunas, the second largest city in Lithuania. We analysed ambulatory case records of 187 ESRD patients dialysed in all 7 hemodialysis centers in the Kaunas region over the year 2002. Results During the year 2002 the unadjusted hospitalization rate over a 1 year period in all dialysed patients (the prevalent patients, n=187) was 1.4 hospitalizations per patient year at risk. There were 17.5 hospital days per patient year at risk, the mean length of one hospitalization being 12.5 days. The most frequent causes of hospitalization were cardiovascular diseases (25%), infections (22%), and access related complications (10%). Of the 187 patients, 55 started hemodialysis in the year 2002 (incident patients). The comparison of prevalent patients with incident patients revealed a higher hospitalization rate in the incident patients (unadjusted hospitalization rate was 1.9 hospitalizations per patient year at risk). The length of hospitalization (29.1 hospital days per patient year at risk) and the mean length of one hospitalization (15.1 days) were longer in the incident patients than the prevalent patients. In the year 2002, the National Sickness Fund paid $361 per year for hospitalizations of one hemodialysis patient and $10,800 per year for the dialysis procedures of one hemodialysis patient. Conclusions The hospitalization rate in Lithuania for patients undergoing hemodialysis is similar to that of other European countries while hospitalization costs are lower.
Effects of Modified Collagen Matrices on Human Umbilical Vein Endothelial Cells
Authors: Markowicz M. , Heitland A. , Steffens G.C.M. , Pallua N. 
Published: January 2018

The most commonly used biomaterials fail to ensure sufficient angiogenesis for fast in vivo incorporation. This results in central necrosis and consequent infection. One way of obtaining a high angiogenic response is the application of vascular endothelial growth factor (VEGF). To obtain a sustained release of these cytokines, heparin was incorporated into collagen matrices using 1-ethyl-3(3-dimethyl-aminopropyl) carbodiimide (EDC) and N-hydroxysuccinmide (NHS). The functionality of the heparinized collagen matrices was then enhanced by immobilization of VEGF via its heparin-binding domain. This procedure changed in vitro degradation behavior and water-binding capacity. Accelerated endothelial cell proliferation was also achieved. A range of different heparin and EDC/NHS concentrations in combination with VEGF induced variation in endothelial cell growth and tubulogenic formation. Polymerized collagen scaffolds presented biointeractive systems with integrated angiogenic activity. This may become a useful tool in the clinical therapy of disorders connected with wound healing.
Multi-Scale Analysis of the Toraymyxin Adsorption Cartridge Part I: Molecular Interaction of Polymyxin B with Endotoxins
Authors: Vesentini S. , Soncini M. , Zaupa A. , Silvestri V. , Fiore G.B. , Redaelli A. 
Published: January 2018

Endotoxins or lipopolysaccharides are the main constituents of the outer leaflet of Gram-negative bacteria membrane and play a central role in the pathogenesis of the septic shock. Polymyxin B has both antibacterial and antiendotoxin capability; indeed it is able to destroy the bacterial outer membrane and bind endotoxin neutralizing its toxic effects. Cartridges containing polymyxin B-immobilized fibers (Toraymyxin PMX-F, Toray Industries, Japan) are used in extracorporeal hemoperfusion to remove circulating endotoxin. The aim of this study is the characterization of the polymyxin B-endotoxin system at the molecular level, thus providing quantitative evaluation of the binding forces exerted in the molecular complex. Polymyxin B was interfaced with five molecular models of lipopolysaccharides differing in their structure and molecular mechanics simulations were performed at different intermolecular distances aimed at calculating the interaction energies of the complex. Binding forces were calculated by fitting interaction energies data. Results show that in the short range the polymyxin B-endotoxin complex is mediated by hydrophobic forces and in the long range the complex is driven by ionic forces only. From a mechanical standpoint, polymyxin B-endotoxin complex is characterized by maximum binding forces ranging between 1.39 nN to 3.79 nN. The knowledge of the binding force behavior at different intermolecular distances allows further investigations at higher scale level (Part II).
Residual Blood Loss in Single Use Dialyzers: Effect of Different Membranes and Flux
Authors: Kalocheretis P. , Vlamis I. , Belesi C. , Makriniotou I. , Zerbala S. , Savidou E. , Zorbas S. , Arvanitis N. , Iatrou C. 
Published: January 2018

Aim/Background The aim of this study was to evaluate the residual blood loss in new type single use dialyzers under the usually prevailing conditions during hemodialysis and to investigate whether or not this loss is dependent on dialyzer membrane composition or flux characteristics. Materials and Methods In 158 hemodialysis (HD) patients, 158 single used dialyzers were studied in corresponding HD sessions. 52/158 dialyzers were made from modified cellulose (acetate, CA or triacetate, CTA) membrane and 106 from synthetic ones (58 with ethyl-vinyl-alcohol (EVAL), 48 with polyacrilonitrile (AN69)). Of those dialyzers 85/158 (58 EVAL+27CA) were low flux (LF) while the other 73 were high flux (HF). Patients underwent 4 hour HD sessions and at the end of the session blood was drawn for the measurement of hematocrit (Ht) and hemoglobin (Hb). Additionally, after the end of dialysis the used dialyzers were rinsed with 1000mL of 0.05% NH3 solution in distilled water. The wash was collected and subsequently Hb was measured using the benzidine method. From the volume of the solution and its concentration of Hb, total Hb of the solution was measured and blood loss in terms of red blood cell (RBC) volume was estimated by the use of the formula: RBC (mL) = Total Hb (g) in the solution x patient's Ht (ml/dL) / Patient's Hb (g/dL). For results to be comparable between dialyzers, RBC volume/m2 of dialyzer membrane was expressed. In 5/158 patients blood loss was also estimated in 6 consecutive HD sessions using the same type of dialyzer. Results For the sum of the dialyzers, blood loss / dialyzer in terms of RBC volume, expressed as median (range), was 0.978 mL (0.01–23.9). There was statistically significant (p<0.001 or p<0.05) higher blood loss with the use of AN69 dialyzer than with the other three. RBCHF>RBCLF (p<0.001) constrained the first group of patients to use a 6% higher dosage of ferrum and 3.5% higher dosage of erythropoietin than the other group to achieve the optimal hemoglobulin values. No difference existed regarding RBC between CA, CTA and EVAL membranes. RBC measured in the small group of 5/158 patients for 6 consecutive HD sessions with the same dialyzer showed a wide range of RBC loss indicating an effect of the human factor. Conclusions Blood loss during HD sessions due to residual blood cell volume inside dialyzers is usually slight using new type single use dialyzers but, sometimes, it can be significant and may contribute to the development or deterioration of preexisting iron deficiency anemia. The results of this study indicated that this loss can be attributed to the membrane composition of the dialyzer or to the human factor and has nothing to do with the ultrafiltration coefficient of the dialyzer.
Ischemic Type Biliary Lesions in Histidine-Tryptophan-Ketoglutarate (HTK) Preserved Liver Grafts
Authors: Moench C. , Otto G. 
Published: January 2018

Ischemic type biliary lesions lead to considerable morbidity following orthotopic liver transplantation. The exact pathogenesis is unknown. One major hypothesis is that insufficient perfusion of the arterial vessels of the biliary tree, especially under perfusion with the high viscous University of Wisconsin solution, might be responsible for ischemic type biliary lesions. Due to low viscosity, HTK solution is reported to have a lower incidence of biliary complications. However, there is no data concerning ischemic type biliary lesions in HTK preserved livers. In this paper we report our results after orthotopic liver transplantation with special regard to ischemic type biliary lesions in liver grafts preserved with HTK solution. Between 09/1997 and 01/2005 300 liver transplantations were performed in our center. Thirty-two (10.7%) liver grafts were preserved with HTK solution, 268 (89.3%) were preserved with UW solution. Six and 43 grafts showed ischemic type biliary lesions after orthotopic liver transplantation in HTK- (18.8%) and UW- (16.0%) groups, respectively (p=0.696). There was no statistical significant difference between the two groups. Donor related factors, recipient age, indication for transplantation, transplantation technique, immunosuppression and ischemia time were comparable in both groups. Ischemic type biliary lesions occurred with the same frequency in HTK preserved livers compared to UW preserved organs. We suggest that low viscosity of the preservation fluid by itself does not guarantee reliable perfusion of the small arteries of a liver graft and a pressure perfusion might be beneficial even in HTK solution.
Antibiotic Resistant Pathogenic Bacteria and Their Resistance Genes in Bacterial Biofilms
Authors: Obst U. , Schwartz T. , Volkmann H. 
Published: January 2018

Biofilm-forming bacteria are ubiquitous in the environment and also include biofilm-forming pathogens. Environmental biofilms may form a reservoir for risk genes and may act as a challenge for human health. Examples of the health relevance of biofilms are the increase in antibiotic resistant bacteria hosted in biofilms in hospital and environment and consequently the interaction of these bacteria with human cells, e.g. in the immune system. Although data concerning the occurrence and spread of resistant bacteria within hospital care units are available, the fate of these bacteria in the environment and especially in the aquatic environment has barely been investigated. Once antibiotic resistant bacteria have entered the environment, a back coupling by ingestion or other possible entry into the host has to be prevented. Therefore a strategy to investigate paths of entry, accumulation and spread of resistant bacteria in environmental compartments has been developed using quantitative determination of genetic resistance determinants. Additionally a bacterial bioassay assessed bioeffectivity thresholds of low antibiotic concentrations. This approach enables an evaluation of the potential of contaminated waters to exert a selection pressure on bacterial communities and thus promote the persistence of resistant organisms. Completed with an indicator system for the identification of sources of multiresistant bacteria a concept for monitoring and evaluation of environmental compartments with respect to their potential of antibiotic resistance dissemination is suggested.
Leptin and β2-Microglobulin Kinetics with Three Different Dialysis Modalities
Authors: Mandolfo S. , Borlandelli S. , Imbasciati E. 
Published: January 2018

Background Leptin is a protein produced by fat cells and involved in body weight regulation. In patients with normal kidney function, leptin has been considered an independent predictor of cardiovascular events. In uremic patients, leptin in plasma serum was assumed to be associated with malnutrition, inflammation and atherosclerosis. Because of its molecular weight and characteristics, leptin can be considered as a protein-bound uremic retention solute. Some authors have reported the possibility of decreasing the serum leptin concentration with high flux membranes, but limited data are available on the elimination with medium-flux membranes or alternative dialysis strategies such as hemodiafiltration. Methods We evaluated the kinetics of leptin and β2m in a study of 18 chronic hemodialysis patients using low-flux, medium-flux and high-flux biocompatible membranes, the last one used in hemodiafiltration (HDF). Blood samples for leptin and β2m were collected pre- and post-treatment and 30 minutes after the end of treatment, over a 1-week period that included 3 dialysis sessions. Clearances of leptin and β2m across the dialyzer were also determined directly from the arterial and venous blood concentrations 60 and 210 minutes after starting dialysis. Results At baseline, all groups showed similar leptin (18.8±4.4 ng/mL) and β2m concentrations (29.2±7.1 ng/mL). After a single dialysis session, a reduction of both solutes was observed with HDF (39.8±1.9%, 78.1±4.9) and medium flux membranes (18.2±0.9%, 52.2±1.7%), whereas the concentrations remained unchanged with the low-flux membranes. After one-week period, a trend of reduction of plasma pre dialysis leptin and β2m were observed with HDF and medium flux membranes. At 60 minutes, HDF showed the best instantaneous clearance across the filter for leptin (56.2±10.1 ml/min) and β2m (75.3±4.4 ml/min). The magnitude of post dialysis rebound of leptin at 30 min was variable and strongly correlated with the instantaneous clearance of the solute (r2= 0.88). Conclusions Leptin serum concentration can be influenced by dialysis modalities and membrane permeability; data on rebound suggest a multicompartimental kinetic of leptin similar to β2m. Leptin removal, as measured by the reduction rate, can be considered as an index of dialysis efficiency for protein-bound uremic retention solutes.
Self-Management Protocol for a Moving-Actuator Type Artificial Heart
Authors: Nam K.W. , Chung J. , Choi S.W. , Sun K. , Min B.G. 
Published: January 2018

In this paper, we describe the development of a self-management protocol for a controller of a moving-actuator type artificial heart, AnyHeart™. The developed protocol analyzes motor current signals and detects abnormal pumping statuses. If preset abnormal pumping statuses are detected by an implemented algorithm, a controller triggers an emergency management procedure and transmits an alarm message to predetermined medical and engineering staffs via a cellular phone network to notify them of an abnormal pumping status occurrence and its likely cause. Results of in vitro performance experiments showed that the developed protocol can detect simulated abnormalities in motor current, manage the operating status of the blood pump during an emergency, and transmit an alarm message as desired.
Improved Neo-Endothelialization of Small Diameter ePTFE Grafts with Titanium Coating
Authors: Cikirikcioglu M. , Sedelnikov N. , Osorio-Da Cruz S. , Khabiri E. , Antal A. Donmez , Tatar T. , Tille J.-C. , Hess O.M. , Kalangos A. , Walpoth B.H. 
Published: January 2018

Background Patency of small synthetic bypass grafts is inferior compared to autologous grafts for revascularization procedures. Titanium coating of foreign surfaces has shown to decrease thrombogenicity, enhance biocompatibility and promote adhesion of endothelial cells. The aim of this study was to test the effect of titanium coating of small diameter ePTFE grafts on short term patency, neo-endothelialization and neointimal proliferation. Methods Bilateral carotid graft interposition was performed in 5 pigs with uncoated (n=5) and titanium-coated (n=5) ePTFE grafts (internal diameter=4 mm, length=5 cm), thus each pig served as its own control. At the end of the study (30 ± 3 days), patency and stenosis severity was assessed by carotid angiography. Animals were sacrificed and grafts were excised for histology and scanning electron microscopy. Morphometry of histologic sections was carried out to determine neointimal proliferation and percentage of neo-endothelial coverage. Results Patency rate was 80% for uncoated and titanium-coated grafts. Quantitative angiography did not show any significant difference in lumen size between two groups. Morphometry revealed a significantly higher cellular coverage with CD 31 positive endothelial cells for titanium-coated (84 ± 19%) than uncoated grafts (48 ± 26%, p<0.001). There was a non significant trend (p=0.112) towards increased neointimal proliferation in titanium-coated (94 ± 61 μm2/μm) compared to uncoated grafts (60 ± 57 μm2/μm). Conclusions Patency rate in uncoated and titanium-coated ePTFE grafts is similar at one month. However, titanium coated grafts show a significant improvement in neo-endothelialization compared to uncoated grafts.