bluuebunny/crossref_metadata_2025 huggingface dataset:
Factors Affecting Plasma Free Fatty Acids Rise during Hemodialysis
Authors: Mingardi G. , Branca E. , Cini M. , Codegoni A.M. , Mecca G. , Bizzi A.
Published: April 2018

We studied the mechanisms responsible for causing acute changes in plasma lipids during hemodialysis. Dialysis decreased plasma triglycerides to the same extent as when heparin was given without dialysis. Cholesterol increased in proportion to hemoconcentration. Plasma free fatty acids (FFA) levels were also increased, but more so than with heparin alone. Glucose and acetate did not play a role, nor did carnitine loss, and hemofiltration elicited similar effects. The rise in plasma FFA is therefore likely to be caused by other as yet unknown mechanism.
Reverse Cascade Filtration of Ascitic Fluid-Preliminary Results
Authors: Valbonesi M. , Torre G.C. , Capra C. , Frisoni R. , Testa R. , Zia S. , Ferrari M.
Published: April 2018

Refractory ascites is an infrequent complication of cirrhosis. Paracentesis and ultrafiltration of the ascitic fluid with intravenous or intraperitoneal reinfusion of the concentrated ascites has been used as therapy for this condition since 1971. The technique is cumbersome and has high morbidity and mortality rates, even if effective. In this paper we describe a new technique that couples secondary filtration for the removal of macromolecules, with ultrafiltration of ascitic fluid. In its very first application 6 patients underwent 8 treatments. No adverse effect was observed and clinical efficacy was good. Up to 60 g of albumin can be saved in a single session lasting less than 2 hours.
Influence of Dialysate and Membrane Biocompatibility on Hemodynamic Stability in Hemodialysis
Authors: Quereda C. , Orofino L. , Marcen R. , Sabater J. , Matesanz R. , Ortuño J.
Published: April 2018

The contributions of membrane biocompatibility, dialysate temperature and sodium concentration to hemodynamic stability during hemodialysis were studied in 8 patients with a high incidence of hemodialysis-induced symptomatic hypotension. Patients were treated during 8 different periods, randomly ordered in each case, resulting from the combination of the following: the membrane, either Cuprophan or Polyacrylonitrile; the dialysate temperature, 37 or 35°C, and the sodium concentration, 133 or 139 mmol/l. The incidence of symptomatic hypotension was lower at 35°C in the entire study with either membrane and either sodium concentration. It was also lower with a sodium concentration of 139 mmol/l with either temperature and either membrane. There was a lower incidence of symptomatic hypotension when using Polyacrylonitrile, but this difference was not significant. We conclude that changes in physicochemical parameters of dialysate lead to worth-while improvement of symptomatic hypotension in hemodialysis patients, but membrane biocompatibility seems to play a minor role.
Optimization of Heparin Anticoagulation during Membrane Plasma Separation
Authors: Frascà G.M. , Buscaroli A. , Borgnino L.C. , Vangelista A.
Published: April 2018

This study analyses 75 membrane plasma exchanges carried out in 18 patients where various amounts of heparin were used to define the heparin kinetic during plasma exchange and the appropriate anticoagulation. A specific assay was employed to measure heparin concentration.

Our results showed that: 1) the heparin distribution volume exceeded the expected value by 10 to 25%; 2) the drug is filtered with a sieving coefficient = 1; 3) the appropriate concentration range is within 0.2 and 0.5 Ul/ml.; 4) the heparin blood levels strictly correlate with a PTT (p<0.001); 5) the individual need for heparin is related to the patient Hct (p<0.001) and plasma flow (p<0.001).

Simple quidelines are provided to determine the appropriate heparin dosage in single patients.
Urea Kinetic Modelling by Partial Dialysate Collection
Authors: Garred L.J. , Rittau M. , McCready W. , Canaud B.
Published: April 2018

Conventional urea kinetic modelling (UKM) has several drawbacks, in particular the complexity of the required calculations and the need for accurate values of parameters which are difficult to measure, such as dialyzer clearance and blood flow. An alternative method of UKM is proposed based on collecting a small fraction of spent dialysate flow for 3 consecutive dialyses. Application of a urea mass balance to the 7 day period permits neglecting changes in body urea stores. Thus no blood sampling is required for most patients. The required calculations are simple and straightforward.

The partial dialysate collection (PDC) method was compared to conventional UKM in a 3 patient, 15 week study. Protein catabolic rate (PCR) from PDC was a smooth curve and consistent with dietary estimation for each patient. Conventional UKM gave variable PCR results which were 17–27% higher on average. This discrepancy was attributed to overestimation of dialyzer clearance. PDC was concluded to be more convenient and accurate than conventional UKM and therefore ideal for routine clinical use
Blood Glucose Measurement by Infrared Spectroscopy
Authors: Zeller H. , Novak P. , Landgraf R.
Published: April 2018

For the development of an implantable artificial endocrine pancreas, a sensor for blood glucose measurement is needed providing a long-term stability. This goal can be achieved by the application of infrared spectroscopy which, unlike electrochemical sensors, responds directly to the glucose molecule.

An investigation under physiological conditions revealed five glucose absorption bands in the near and middle infrared range. These are 1040, 1085, 1109, 1160 and 1365 cm–1. Only the 1040 cm–1 frequency coincides with none of the other infrared-active blood substances like proteins, lipids and urea. Nevertheless, the other absorption bands too, especially the 1109 cm–1 frequency, can be used for blood glucose measurement, if the superimposed absorptions are compensated. Methods for the compensation have been found. Technically feasible embodiments of an infrared glucose sensor are described.
First Observation of Hopeïte and Parascholzite in Fibrous Capsules Surrounding Silicone Breast Implants
Authors: Rolland C. , Ledoux R. , Guidoin R. , Marceau D.
Published: April 2018

We observed mineralization in 32.6% of the capsular tissue of 97 mammary prostheses recovered after surgical excision. Three distinct mineralogical phases were identified. The first was composed of common hydrated carbonate hydroxylapatite, a well-known physiological and pathological mineral. Hopeïte and parascholzite constituted the second and third phases. They are zinc and calcium hydrate phosphates that have not been observed previously in human tissues. Statistical analysis of the data showed relationships between the presence of mineralizations and the manufacturers on the one hand, and the presence of Dacrorf fixation patches at the surface of the prostheses on the other.
L-Lactate for High-Efficiency Hemodialysis: Feasibility Studies and a Randomized Comparison with Acetate and Bicarbonate
Authors: Dalal S.P. , Ajam M. , Gupta D.K. , Gupta R. , Nawab Z. , Manahan F.J. , Ing T.S. , Daugirdas J.T.
Published: April 2018

We evaluated the feasibility of using L-lactate as a base for hemodialysis. In one study, acid-base changes using 40 mM L- or DL-lactate were compared. In a second study, acid-base status using various amounts of L-lactate exclusively was studied. The third study compared symptoms and acid-base changes during 9 weeks of high-efficiency dialysis when using L-lactate, acetate, or bicarbonate as base.

In the first study, plasma bicarbonate changes were equivalent with 40 mM L-lactate and 40 mM DL-lactate, but overall correction of acidosis appeared to be suboptimal. In the second study, when compared to a bicarbonate control period, correction of acidosis was reduced when using 40 mM L-lactate + 4 mM acetate solution, but increased when using a 46 mM L-lactate + 4 mM acetate solution. In the third study, correction of acidosis was comparable when using 42 mM L-lactate + 4 mM acetate, 39 mM acetate, or 35 mM HCO3 + 4 mM acetate. Whereas 46% ± 12 (SEM) treatments “failed” because of symptoms when using acetate, the percentages of “failed” treatments were only 7%±4.2 with L-lactate (p<0.05) and 11% ± 4.2 with bicarbonate (p < 0.05).

The results suggest that L-lactate is a suitable dialysis solution base that is capable of correcting chronic uremic acidosis. During high-efficiency dialysis, the incidence of intradialytic symptoms with L-lactate is comparable to that with bicarbonate and less than that with acetate.
Predicting Need for Surgical Drainage of Pericardial Effusion in Patients with End-Stage Renal Disease
Authors: Leehey D.J. , Daugirdas J.T. , Popli S. , Gandhi V.C. , Pifarré R. , Ing T.S.
Published: April 2018

The best approach to treatment of pericarditis accompanied by substantial pericardial effusion in end-stage renal disease (ESRD) patients is unknown. In a review of our experience, we found that ESRD patients with moderate-to-large or large (circa 250 mL or larger) pericardial effusions usually failed to improve with intensive dialysis and ultimately required surgical drainage of the effusion. Multivariate analysis revealed that effusion size was by far the most important factor predicting need for surgery. Since early pericardial drainage obviates the risk of sudden tamponade, we recommend that surgery without prior intensive dialysis therapy be considered in such patients.
Hemodialysis and the Acute-Phase Response in Chronic Uremic Patients
Authors: Trznadel K. , Luciak M. , Paradowski M. , Kubasiewicz-Ujma B.
Published: April 2018

In comparison with healthy persons, chronic uremic patients on regular hemodialysis treatment had significantly higher blood serum concentrations of α1-acid glycoprotein, ceruloplasmin and C4 complement component, while levels of haptoglobin, C3 and transferrin were lower. Serum α2-macroglobulin and α1-antitrypsin levels were similar in both groups. Hemodialysis with cuprophan membrane induced only slight changes in some of these glycoproteins during a 48-hour follow-up period. Seven hours after termination of hemodialysis slight, but significant, decreases in blood serum transferrin and α1-antitrypsin concentrations were observed. Hemodialysis thus does not seem to induce a conspicuous acute-phase reaction.
Dipyridamole Thallium-201 Perfusion Imaging for the Study of Ischemic Heart Disease in Hemodialysis Patients
Authors: Marcen R. , Lamas S. , Orofino L. , Quereda C. , Barcia F. , Castro J.M. , De Caso P. Alonso , Ortuño J.
Published: April 2018

To assess the usefulness of dipyridamole thallium perfusion imaging in the evaluation of myocardial perfusion in hemodialysis (HD), we studied 29 HD patients divided into three groups: A) 13 patients with clinical angina, B) 8 patients without angina but similar in age, sex, time on HD and hematocrit and C) 8 young asymptomatic patients (mean age 33 ± 9.7 years). Dipyridamole thallium-201 (TI-201) perfusion imaging revealed myocardial perfusion defects in 8 patients (61%) from group A, 4 (50%) from group B and 1 (12.5%) from group C. These defects were localized in the inferior, posterior and septal segments of the left ventricle. Abnormal myocardial perfusion was associated with age over 50 years and aortic calcifications (p < 0.05). Eight patients died within the following four years. All had aortic calcifications (p < 0.001). Our results show that myocardial perfusion defects are frequent even in non-symptomatic HD patients. This suggests that ischemic heart disease could be more frequent than estimated by clinical symptoms alone. TI-201 scintigraphy may be a useful non-invasive procedure in cardiological evaluation of HD patients
Beta 2-microglobulin Serum Levels during Dialysis: Effect of Cuprophan and Serum Osmolality Changes
Authors: Sulková S. , Votruba T. , Lapčík O. , Válek A.
Published: April 2018

New cuprophan dialysers were used in twenty, re-used dialysers in twelve dialyses and new dialysers in ten sequential ultrafiltrations. Serum beta 2-microglobulin (β2m) concentration was measured before and after all these procedures. Serum osmolality changes were compared with changes in serum β2m concentrations. These concentrations rose in dialyses with new and re-used dialysers, but remained unchanged during sequential ultrafiltration. β2m increased with serum hypo-osmolality, decreased with serum hyperosmolality and did not change during iso-osmolar dialysis. These results indicate that cuprophan membrane does not raise β2m concentration during dialysis. It is hypo-osmolality that is responsible for the increment of β2m in serum.
Hemodialysis-Related Induction of β2-Microglobulin Synthesis and Release by Mononuclear Phagocytes
Authors: Knudsen P.J. , Shaldon S. , Floege J. , Koch M.
Published: April 2018

We have investigated β2-microglobulin (β2M) synthesis and release by blood leukocytes and isolated mononuclear phagocytes. Since β2M was discovered to form amyloid fibrils in patients undergoing long term, chronic hemodialysis and monomeric β2M levels in plasma of these patients are highly elevated, and since hemodialysis-related factors that increase β2M production are unknown, we evaluated β2M production by mononuclear phagocytes under a variety of conditions. We utilized a novel enzyme-lined immunoabsorbant assay to quantitate β2M release. Adherence of macrophages onto polystyrene or Cuprophan membranes does not induce β2M synthesis or release. In contrast, interaction of macrophages with lipopolysaccharide, gamma-interferon, tumor necrosis factor, or interleukin 1 induces synthesis or release. In contrast, interaction of macrophages with lipopolysaccharide, gamma-interferon, tumor necrosis factor, or interleukin 1 induces synthesis and release of β2M, indicating that β2M synthesis is increased during macrophage activation. Exposing leukocytes or macrophages to changes in osmotic or oncotic pressure induces a rapid release of β2M and interleukin 1 into the cellular medium. These results suggest that during hemodialysis, β2M production is more likely to result from endotoxin contamination, or osmotic and oncotic changes, rather than direct interaction of mononuclear phagocytes with cellulosic membranes.
Hemofiltration in Myoglobinuric Acute Renal Failure
Authors: Winterberg B. , Ramme K. , Tenschert W. , Winterberg G. , Rolf N. , Wendt M. , Teerling K. , Lison A.E. , Zumkley H.
Published: April 2018

The frequency of myoglobinuric renal failure is estimated between 8 and 20%. Despite early onset of therapy often the use of renal substitution by hemodialysis or hemofiltration is required. This study of the clinical course of nine patients with myoglobinuric acute renal failure reveals continuous arterio-venous hemofiltration (CAVH) to have an effective clearance for myoglobin. Thus, the time until recovery of renal function as well as the frequency of secondary complications in rhabdomyolysis induced acute renal failure can be distinctly reduced.
Computer Simulation of Ciprofloxacin Pharmacokinetics in Patients on CAPD
Authors: Mrhar A. , Karba R. , Drinovec J. , Primožič S. , Varl J. , Bren A.F. , Kozjek F.
Published: April 2018

Continuous ambulatory peritoneal dialysis (CAPD) has become an accepted alternative to chronic hemodialysis in the treatment of end-stage renal disease. The method utilizes the diffusion of drugs from the blood through the peritoneal membrane to the peritoneal cavity if administered intravenously (IV) and perorally (PO) and in the opposite direction if applied intraperitoneally (IP). The present work uses an open, two-compartment pharmacokinetic model reversibly linked with the compartment representing the peritoneal cavity and an analog-hybrid computer to simulate drug levels in sampled and unsampled compartments under conditions of various routes of administration (IV, IP and sequential IV, IP and PO) and different clinical status (presence and absence of peritonitis). The drug chosen for simulation was ciprofloxacin (CIP), a new synthetic antibacterial agent of the 4-quinolone group. Eight patients were included in the study, and CIP concentrations in plasma and dialysate were obtained by HPLC analysis to assess the reliability of the model and the efficiency of the sequential dosing scheme. CIP plasma and dialysate levels were adequate for the majority of microbes causing CAPD peritonitis. The proposed regimen was efficient in 85% of cases.
Beta 2- Microglobulin Elimination Characteristics during Hemofiltration with Acrylonitrile and Polysulfone Membrane Hemofilters
Authors: Kandus A. , Ponikvar R. , Drinovec J. , Pavlin K. , Ivanovich P.
Published: April 2018

Elimination characteristics of beta 2- microglobulin (BMG) during hemofiltration (HF) with acrylonitrile (AN69) and polysulfone (PS) hemofilters were investigated in a prospective clinical investigation. Seven chronic uremics on regular HF were treated for 4 weeks, three times a week, with AN69 hemofilters. The study was then repeated with PS hemofilters. There were no significant differences in the patients’ body weight, the ultrafiltrate volume per session, and the duration of each HF session between both treatments. At the start of HF, arterial plasma concentration of BMG was (for AN69) 33.5±4.0 mg/L (mean±SD) and (for PS) 35.8±6.5 mg/L (NS); at the end of HF it was (for AN69) 11.0±1.8 mg/L and (for PS) 17.5±4.2 mg/L (p<0.001). The amount of BMG in total ultrafiltrate was (for AN69) 179.3±22.6 mg and (for PS) 140.6±26.8 mg (p<0.02). With AN69 hemofilter, maximum BMG plasma clearance and sieving coefficient were 51.0±9.5 mL/min’ and 0.42±0.04 at 60 minutes. With PS hemofilter, maximum BMG plasma clearance and sieving coefficient were 37.4±5.7 mL/min and 0.27±0.03 at 15 minutes. Twenty-two percents of BMG entering the AN69 hemofilter at 15 minutes were adsorbed on the membrane (p<0.001). BMG elimination with the AN69 hemofilter was more efficient than with the PS hemofilter. Long-term studies will be necessary to demonstrate whether this difference is of any clinical significance.
Serum LDH and LDH Isoenzymes in Chronic Renal Failure: Effect of Hemodialysis
Authors: Vaziri N.D. , Miyada D.S. , Kim I. , Reid J. , Ocariz J.
Published: April 2018

Serum levels of several commonly measured enzymes are abnormal in patients with end-stage renal disease (ESRD). In the present study we measured serum total LDH activity and LDH isoenzymes in a group of 25 ESRD patients shortly before, during, and immediately after hemodialysis. Baseline serum total LDH activity in the ESRD group was midly but significantly higher than that found in the normal control group. The observed elevation was associated with an isomorphic pattern. Single passage of blood through the extracorporeal apparatus led to a rise in total LDH, LDH-3, LDH-2 and LDH-4, a pattern consistent with release from the platelets. A steady increase was noted in total LDH, LDH-5 and LDH-1 of arterial blood during hemodialysis. This was thought to be due to ultrafiltration-induced hemoconcentration, enzyme release from the formed elements within the extracorporeal circuit and complement-mediated leukocyte activation and pulmonary leukostasis. These observations should be taken into consideration with regards to interpretation of LDH and LDH isoenzyme values and proper time of blood sampling in ESRD patients.
Peritoneal Catheters: A Comparative Study of Column Disc and Tenckhoff Catheters
Authors: Shah G.M. , Sabo A. , Nguyen T. , Juler G.L.
Published: April 2018

A functioning peritoneal access is crucial to the success of peritoneal dialysis. We report retrospective analysis of our experience using 44 Tenckhoff and 23 column disc, double-cuff, catheters in 46 patients receiving peritoneal dialysis. Postoperative care was identical in both groups. Both catheter groups were comparable with regards to age, sex, obesity and prior abdominal surgery. Catheter removal due to drainage failure was significantly greater with the column disc than the Tenckhoff catheters (22% vs 5%, p = 0.04). In addition, 39% of column disc catheters compared to 11% Tenckhoff catheters were removed as a result of therapy resistant peritonitis (p = 0.011). Furthermore, there was a greater incidence of peritonitis with the column disc than with the Tenckhoff catheters at the end of the first year (71% vs 42%, p < 0.01). There was no difference between the two groups with respect to other complications, such as pericatheter leak, catheter infections, catheter cuff-extrusion or hernia. Our experience indicates that the column disc catheter is associated with higher complication rates and does not offer any advantage over the Tenckhoff catheter
Estimation of Shear Stress-related Blood Damage in Heart Valve Prostheses - in Vitro Comparison of 25 Aortic Valves
Authors: Giersiepen M. , Wurzinger L.J. , Opitz R. , Reul H.
Published: April 2018

The hemodynamics of heart valve prostheses can be reproducibly investigated in vitro within circulatory mock loops. By measuring the downstream velocity and shear stress fields the shear stresses which are clinically responsible for damage to platelets and red blood cells can be determined.

The mechanisms of damage and the effects of shear stresses on blood corpuscles were investigated by Wurzinger et al. (3, 4) at the Aerodynamics Institute of the RWTH Aachen. In the present study, the above data are incorporated into a mathematical correlation, which serves as a basic model for the estimation of blood damage.

This mathematical model was applied to in vitro investigations of 25 different aortic valve prostheses. The results were compared to clinical findings. In most cases agreement was good, indicating that this model may be directly applied to the clinical situation. This new method facilitates the estimation of clinically expected blood damage from in vitro measurements. It may be useful for the development and evaluation of new valve prostheses. By comparative evaluation of different valve types it also provides additional information to help the implanting surgeon select the optimum valve for his patient.
Acute Renal Failure in Sickle Cell Anemia
Authors: Sklar A.H. , Perez J.C. , Harp R.J. , Caruana R.J.
Published: April 2018

We performed a case-control study of acute renal failure (ARF) in patients hospitalized with sickle cell anemia (SCA). Twelve of the 116 patients (10.3%) whose records were suitable for analysis were diagnosed as having ARF based on a minimum of doubling of their serum creatinine levels (mean rise was 205 ± 49%). ARF patients were more likely to have been admitted with infection and had a lower mean hemoglobin level than the control group. Volume depletion was the most common identifiable cause for ARF. Two of 3 patients with severe ARF received dialytic support. Ten of 12 ARF patients survived and subsequently had recovery of renal function.
Kinetics of Anti-Xa Activity during Combined Defibrotide - Heparin Administration in Hemodialysis
Authors: Buccianti G. , Valenti G. , Lorenz M. , Cresseri D. , Strada E. , Nazzari M.
Published: April 2018

Defibrotide, a polydesoxyribonucleotide derivative with antithrombotic and fibrinolytic activity, capable of inducing the release of PGI2 from vascular endothelia, was proposed as an alternative to standard heparin coverage during blood dialysis for patients at risk of bleeding. The original procedure featured the preliminary washing of the dialysis circuit with heparin, which was then recirculated and eliminated, and the two drugs, heparin and defibrotide, are known to interact with each other. The purpose of this present study was to explore the ex-vivo heparin activity (assessed as anti-Xa activity) in diverse hemodialysis models using defibrotide (800 mg intravenous, in 4 bolus injections) and various dosages of heparin. Anti-Xa activity is negligible in dialysis conducted with defibrotide alone. When the circuit was prewashed with heparin (5000 and 2500 IU), there was evident anti-Xa activity (0.3-0.5 U/ml) in the first 30-60 minutes of dialysis; continuous heparin infusion (500 U/hour) resulted in high anti-Xa activity levels at the end of dialysis. Thus the best hemodialysis procedure for patients at high risk of bleeding should be one utilizing only defibrotide, or defibrotide plus small amounts of calcium heparin infused at the rate of 500 U/hour for not more than two hours.
New Approaches for Biocompatibility Testing Using Cell Culture
Authors: Doillon C.J. , Cameron K.
Published: April 2018

We are proposing two modified assays for biocompatibility testing which analyze the effects of cytotoxic substances leached from a biomaterial in cell culture. The biocompatibility of two vascular prostheses made of polytetrafluoroethylene was analyzed using the modified assays. One test, the “fluid medium assay” was modified by using small pieces of graft glued to a screening lid, thereby reducing the possibility of mechanical injury to cultured cells by free fragments of the tested biomaterial. Another test, the “cell inhibition assay” was modified in that the biomaterial to be tested was ground into small pieces while at very low temperature. The measure of cell toxicity used was the effect on DNA replication. Our results suggest that these modified assay methods can be used to evaluate the biocompatibility of biomaterials.
Study of Parameters Involved in Specific Immunoadsorption of Apolipoprotein B
Authors: Regnault V. , Rivat C. , Marcillier P. , Pfister M. , Michaely J.P. , Didelon J. , Schooneman F. , Stoltz J.F. , Siadat M.
Published: April 2018

A therapeutic immunoadsorption system on immobilized and anti-apolipoprotein B as a plasma cholesterol lowering procedure was optimized. Several antibodies were compared and highest adsorption capacity was obtained with goat polyclonal antibodies. Optimum quantities of antibodies to be immobilized on the gel and quantities of apo-B to be applied to columns were determined. The amount of antibodies released from immunoadsorbents can be minimized by treatment with a 0.005% glutaraldehyde solution with an acceptable reduction rate of adsorption capacity. Each phase, adsorption and desorption respectively, were well-defined and synchronized so two columns could be used in parallel in an automated procedure.

In these conditions, the immunoadsorption system can efficiently, specifically and safely remove cholesterol and has to be subjected to clinical trials.
Constant Blood Flow during Single-Needle Dialysis is Unnecessary
Authors: Polaschegg H.D. , Wojke R.
Published: April 2018

Single-needle (SN) dialysis employs tidal blood flow at the point of vascular access. The simplest SN systems convert this tidal flow to a pulsatile flow in the dialyser. It has been assumed that constant flow through the dialyser is necessary for optimal efficiency. Therefore SN blood circuits are designed to smooth the pulsatile flow in the dialyser to a relatively constant flow. This increases the complexity and cost of the SN system. In order to test the hypothesis that pulsatile flow results in lower clearances than constant flow, we performed measurements of clearance in vitro using pulsatile blood flow at time-averaged rates of 50-250 ml/min and tidal volumes 200-100 ml/min. These were compared with clearances using constant blood flow at the same rates. At all flow rates and at tidal volumes up to 50 ml, the clearance measurements obtained during pulsatile flow were identical to those obtained during constant flow.
Cavitation Threshold with Respect to Dp/Dt: Evaluation in 29 Mm Bileaflet, Pyrolitic Carbon Heart Valves
Authors: Kingsbury C. , Kafesjian R. , Guo G. , Adlparvar P. , Unger J. , Quijano R.C. , Graf T. , Fisher H. , Reul H. , Rau G.
Published: April 2018

A total of 15 bileaflet mechanical heart valves were studied in a pulse duplicator at the Helmholtz Institute (Aachen, Germany) under conditions approximating first, a physiological pressure curve and subsequently, a sinusoidal pressure curve. In this study Edwards-Duromedics valves of the modified specification were compared with the earlier version of the Edwards-Duromedics valve as well as with St. Jude Medical valves. Each valve was tested at a series of nine (9) conditions. At each condition, without altering the valve installation or the systemic conditions, each valve was filmed by two separate video systems: the Helmholtz Institute strobe light system and a high speed video recording system. All data, as recorded by each system, was then independently analyzed by both of the two contributing groups and subsequently compared. In this manner, it was possible to objectively verify not only the consistency of the data obtained, but to also determine the relative reliability of the methods for cavitation threshold detection.
Adequacy of Continuous Ambulatory Peritoneal Dialysis
Authors: Tzamaloukas A.H. , Murata G.H.
Published: April 2018

Adequacy of continuous ambulatory peritoneal dialysis (CAPD) and its variants is assessed by clinical outcomes, biochemical parameters and clearance parameters. Clinical outcomes lack specificity and probably sensitivity. Nevertheless, they constitute the “gold standard” to which any other method assessing dialysis adequacy must be compared. Biochemical parameters are both non-sensitive and non-specific and cannot be used to assess dialysis adequacy. Clearance of small molecular weight azotemic substances (urea, creatinine) presents considerable computational problems and interpretative difficulties. In preliminary studies, clearance studies have been able to differentiate between peritoneal dialysis patients having symptoms of inadequate dialysis and those clinically adequately dialyzed. Among population outcomes (morbidity, maintenance of peritoneal dialysis for long periods, hospitalization rate, mortality), only mortality sems to be associated with low clearances in retrospective studies. Prospective multicenter studies comparing clearance values to clinical outcomes are needed to evaluate clearance studies as methods of assessing peritoneal dialysis adequacy.
Hemodialysis: Evidence of Enhanced Molecular Clearance and Ultrafiltration Volume by Using Pulsatile Flow
Authors: Runge T.M. , Briceño T. J.C. , Sheller M.E. , Moritz C.E. , Sloan L. , Bohls F.O. , Ottmers S.E.
Published: April 2018

We describe several in vitro experiments showing evidence that pulsatile flow hemodialysis enhances ultrafiltration volume and molecular clearance as compared with steady flow hemodialysis. A new pulsatile pump and a conventional roller pump were compared using different hollow fiber dialyzers and a simulated blood solution containing urea, aspartame and vitamin B-12 at different flow rates and configurations. Ultrafiltration volume and concentration of urea, aspartame and B-12 were measured and molecular clearance (K) calculated. Ultrafiltration volume markedly increased with pulsatile flow. After 10 min K for urea with pulsatile flow was higher in all experiments even when ultrafiltration was prevented. Clearance of aspartame and B-12 also increased with pulsatile flow. We propose three mechanisms by which pulsatile flow is more efficient than steady flow hemodialysis: greater fluid energy, avoidance of molecular channeling and avoidance of membrane layering. We hypothesize that using pulsatile flow in hemodialysis can significantly shorten the duration of dialysis sessions for most of the patients, and consequently reduce the duration of the procedure and its cost.
Alterations in Erythrocyte Morphology Induced by Blood Pumps
Authors: Calzavara P. , De Angeli S. , Nieri A. , Furlan C. , Bolzonella R. , da Porto A.
Published: April 2018

A scanning electron microscopy was used after in vitro and in vivo tests to investigate any alterations caused by the peristaltic roller pump in erythrocyte morphology. The electron micrographs of samples were examined as follows: 1) by image analyser; 2) by applying Bessis's classification for the qualitative study of crenated red blood cells (RBCs). The in vitro test was repeated four times using blood from healthy donors. Each basal blood sample was divided into 250 ml portions, each of which was recirculated for 12 minutes at different flow rates. In order to verify any persistent erythrocyte damage caused by the peristaltic pump, 15 minutes after recirculation at 450 ml/min, another sample was prepared using the blood remaining from the last test. A statistically significant direct correlation was found between blood flow (Qb) increase and the percentage of morphologically altered RBCs, when either using an image analyser (r = 0.97; p < 0.05) or Bessis's classification (r = 0.95; p < 0.05). However, neither method showed any statistically significant difference between the percentage of deformed RBCs, determined in the basal sample, or in the percentage found at the end of the 450 ml/min test after standing 15 minutes at room temperature. The in vivo test was carried out on 6 patients over 2 dialysis sessions, which differed only for the Qb: 250 versus 400 ml/min. The two dialysis sessions gave comparable results when using both study methods regarding the presence of deformed RBCs. While Bessis's classification showed a significant drop in the post-dialysis percentage of dysmorphic RBCs compared to the pre-dialysis value, both with a Qb of 250 ml/min and 400 ml/min, no significant change was found with the image analyser. The contradictory results of the two tests can be attributed to the presence of spherocytes and stomatocytes in the in vivo test which on the other hand were absent in the in vitro test and not easily distinguished by the image analyser with the parameter used. Reduction in the number of deformed RBCs after dialysis in the in vivo test can be attributed to improvement in the acidosis, correction of the hydroelectric imbalances and removal of toxic substances as a result of dialysis, thus allowing the echinocytes, spherocytes and stomatocytes to be transformed into discocytes.
Vasoactive Agents and Blood Pressure Regulation in Sequential Ultrafiltration and Hemodialysis
Authors: Odar-CederlÖf I. , Theodorsson E. , Eriksson C.G. , Hamberger B. , Tidgren B. , Kjellstrand C.M.
Published: April 2018

Hypotension is a common and sometimes dangerous side effect of hemodialysis. Its etiology is multifactorial and largely unknown. Earlier studies on the role of endogenous blood pressure regulating agents such as catecholamines and renin have rendered conflicting results. We studied the influence of ultrafiltration and isovolemic hemodialysis separately on the plasma concentrations of the following blood pressure regulating agents: adrenaline, noradrenaline, dopamine, neuropeptide Y, calcitonin gene-related peptide (CGRP), renin (PRA), angiotensin II, vasopressin, aldosterone and Cortisol. During isolated ultrafiltration, plasma levels of two strong vasoconstrictors (noradrenaline and angiotensin II) and one strong vasodilator (calcitonin gene-related peptide, CGRP) increased significantly (noradrenaline 3.24 ± 0.60 nM to 4.31 ± 0.55 nM; p = 0.032, angiotensin II 19.74 ± 3.46 pmol/l to 28.49 ± 7.24 pmol/l; p= 0.047) No symptomatic hypotension occurred. At the end of isovolemic hemodialysis, plasma levels of all the vasoconstricting agents had decreased to pretreatment values, but those of CGRP had continued to rise (from 85.3 ± 17.6 pmol/l to 114.5 ± 25.3 pmol/l, p=0.031). During isovolemic hemodialysis, blood pressure fell to symptomatic levels, but was restored at the end of treatment. The study shows that hemodialysis patients respond to fluid removal by ultrafiltration with an increase in plasma levels of CGRP, noradrenaline and angiotensin II. The net effect is an appropriate vasoconstriction and adequate blood pressure is maintained during isolated ultrafiltration. During hemodialysis, the patients’ blood volumes remained unchanged as evident by a stable hematocrit, the vasoconstrictor hormones returned to normal levels, but in several patients there was a continuous release of vasodilating CGRP. Hypotension, then occurred in these patients due to the imbalance between vasoconstricting and vasodilating factors.
Extracorporeal Circulation in European Economic Community (ECC in EEC): 1979–1989
Authors: Lautier A. , Gille J.P. , Juvin A.M. , Gaillard D. , Sargentini J.C.
Published: April 2018

This study determines the evolution of ECC in EEC. After recollecting the great stages of ECC since its routinely use in open heart surgery, the study situates its position in the entire world taking into account several indexes like the Gross National Product (GNP) and its evolution, the life expectancy and some other factors either technical or economical. Only a coarse analysis could be done for Europe due to an unsteady evolution. A more detailed analysis has been achieved for France thanks to a greater number of data. In such a study the major difficulty is to estimate the relevance and consistancy of data which can change very quickly and are provided either by companies or by other organization.
Hemodialysis as a Treatment of Severe Ethanol Poisoning
Authors: Atassi W.A. , Noghnogh A.A. , Hariman R. , Jayanthi S. , Cheung S.F. , Kjellstrand C.M. , Ing T.S.
Published: April 2018

A 64-year-old woman presented with coma and shock due to severe ethanol intoxication. Her initial, markedly elevated blood alcohol level of 136.5 mM fell only by 16% after a 4-hour period of conservative treatment consisting of mechanical respiration and the administration of intravenous fluids, vasopressors and inotropics. Subsequent hemodialysis rapidly reduced her blood ethanol concentrations to less threatening levels, with prompt restoration of her consciousness. Hemodialysis may be life-saving and should be considered in patients with severe ethanol intoxication.
Effects of surfactants on the properties of epoxy/graphene nanocomposites
Authors: Wei Jiacheng , Saharudin Mohd Shahneel , Vo Thuc , Inam Fawad
Published: April 2018

Recently, graphene has attracted extensive research interests due to its superior mechanical, electrical and thermal performance. Small loadings of graphene can increase the properties of epoxy significantly. However, because of the large surface area of graphene, it is a challenge to disperse graphene in liquid epoxy. Strong van der Waals force causes reaggregation of graphene in the matrix. As commonly used surfactants, sodium dodecyl sulphate and gum arabic have been used a lot to de-bundle graphene, however, their dispersing efficiencies for graphene in epoxy matrix is unknown. Therefore, to evaluate their dispersing efficiencies, epoxy/graphene nanocomposites had been made and mechanical properties, dynamic mechanical analysis, thermal gravimetric analysis and scanning electron microscopy tests of nanocomposites had been conducted. The results show that the properties of nanocomposites had been enhanced largely after using sodium dodecyl sulphate and gum arabic. Sodium dodecyl sulphate shows higher dispersing effectiveness than gum arabic.
Optimizing the buckling strength of filament winding composite cylinders under hydrostatic pressure
Authors: Ke Chun Shen , Guang Pan
Published: April 2018

This paper presents the design optimization of filament winding composite cylindrical shell under hydrostatic pressure to maximize the critical buckling pressure. To this end, an optimization framework has been developed by employing numerical solution integrated with genetic algorithm. The design variables are fiber orientation and the corresponding number of layers. The framework is used to find the optimal design of filament winding composite cylindrical shell subjected to hydrostatic pressure. Three types of winding pattern are investigated, and the maximum critical buckling loads are increased by 26.14%, 25.82% and 20.95% compared with the base line, respectively. The influences of design variables on the critical buckling pressure are investigated. Results show that filament winding angles have more significant effect on the critical buckling pressure than the corresponding number of layers. Comparative study is carried out to verify the efficiency and accuracy of the optimization framework. Compared with the finite element analysis, the optimization framework has significant advantages in terms of calculation efficiency.
Constantinian Toleration
Authors: Lloyd Vincent
Published: April 2018

Recent secular theorists of toleration have turned to Christian thought as a resource to overcome problems faced by secular-liberal accounts of toleration. This review essay examines three such projects, one in the tradition of Thomistic virtue ethics, another in the tradition of Frankfurt School critical theory, and another in political theory. While Christian ethics can learn from the methods and theoretical machinery deployed in these studies, each study assumes that the question of toleration is posed from a position of power and privilege. The essay asks what it might mean to consider toleration from the perspective of a marginalized community—like the early Christians.
Numerical studies on the acoustic characteristics of the U-shaped corrugated pipes and application investigations
Authors: Xue Fei , Sun Beibei , Jiao Renqiang , Chen Jiandong
Published: April 2018

This paper presents a numerical study on the effect of structural parameters on acoustical transmission loss of U-shaped corrugated pipe using the control variable method. Then, the interactions between the cutoff frequencies and structural parameters are modeled based on the dimension analysis method using the numerical results. An investigation into the application of the U-shaped corrugated pipe into a simple expansion chamber muffler is carried out using both numerical and experimental methods. The results show that the U-shaped corrugated pipes have unique acoustic characteristics in noise attenuation, which resembles a resonant muffler. Furthermore, the numerical results of the transmission loss of U-shaped corrugated pipes are in good agreement with experimental results, which indicates that the transmission loss results obtained by acoustic finite element method is accurate. In addition, the corrugation height, corrugation length, and corrugation internal diameter are the factors that affect the acoustical behavior of the corrugated pipe most significantly. Moreover, the proposed empirical formulas for predicting the cutoff frequencies of U-shaped corrugated pipes are verified with high accuracy and with a prediction error within ±3.0%. What is more, the application of U-shaped corrugated pipes in expansion chamber muffler can effectively reduce the noise in the mid- to high-frequency band, which is useful to reduce the muffler volume and the amount of sound-absorbing material. Hence, automobile mufflers can be designed in a much more environmentally friendly way. In conclusion, this work could provide a theoretical basis for the acoustical design of U-shaped corrugated pipes, and it initiates a new research and application field for corrugated pipes as well.
Production Practice During Language Learning Improves Comprehension
Authors: Hopman Elise W. M. , MacDonald Maryellen C.
Published: April 2018

Language learners often spend more time comprehending than producing a new language. However, memory research suggests reasons to suspect that production practice might provide a stronger learning experience than comprehension practice. We tested the benefits of production during language learning and the degree to which this learning transfers to comprehension skill. We taught participants an artificial language containing multiple linguistic dependencies. Participants were randomly assigned to either a production- or a comprehension-learning condition, with conditions designed to balance attention demands and other known production–comprehension differences. After training, production-learning participants outperformed comprehension-learning participants on vocabulary comprehension and on comprehension tests of grammatical dependencies, even when we controlled for individual differences in vocabulary learning. This result shows that producing a language during learning can improve subsequent comprehension, which has implications for theories of memory and learning, language representations, and educational practices.
A Bayesian two-stage spatially dependent variable selection model for space–time health data
Authors: Choi Jungsoon , Lawson Andrew B
Published: April 2018

In space–time epidemiological modeling, most studies have considered the overall variations in relative risk to better estimate the effects of risk factors on health outcomes. However, the associations between risk factors and health outcomes may vary across space and time. Especially, the temporal patterns of the covariate effects may depend on space. Thus, we propose a Bayesian two-stage spatially dependent variable selection approach for space–time health data to determine the spatially varying subsets of regression coefficients with common temporal dependence. The two-stage structure allows reduction of the spatial confounding bias in the estimates of the regression coefficients. A simulation study is conducted to examine the performance of the proposed two-stage model. We apply the proposed model to the number of inpatients with lung cancer in 159 counties of Georgia, USA.
The Effect of Tissue Preparation and Donor Age on Striatal Graft Morphology in the Mouse
Authors: Harrison David J. , Roberton Victoria H. , Vinh Ngoc-Nga , Brooks Simon P. , Dunnett Stephen B. , Rosser Anne E.
Published: April 2018

Huntington's disease (HD) is a progressive neurodegenerative disease in which striatal medium spiny neurons (MSNs) are lost. Neuronal replacement therapies aim to replace MSNs through striatal transplantation of donor MSN progenitors, which successfully improve HD-like deficits in rat HD models and have provided functional improvement in patients. Transplants in mouse models of HD are more variable and have lower cell survival than equivalent rat grafts, yet mice constitute the majority of transgenic HD models. Improving the quality and consistency of mouse transplants would open up access to this wider range of rodent models and facilitate research to increase understanding of graft mechanisms, which is essential to progress transplantation as a therapy for HD. Here we determined how donor age, cell preparation, and donor/host strain choice influenced the quality of primary embryonic grafts in quinolinic acid lesion mouse models of HD. Both a within-strain (W-S) and a between-strain (B-S) donor/host paradigm were used to compare transplants of donor tissues derived from mice at embryonic day E12 and E14 prepared either as dissociated suspensions or as minimally manipulated tissue pieces (TP). Good graft survival was observed, although graft volume and cellular composition were highly variable. The effect of cell preparation on grafts differed significantly depending on donor age, with E14 cell suspensions yielding larger grafts compared to TP. Conversely, TP were more effective when derived from E12 donor tissue. A W-S model produced larger grafts with greater MSN content, and while high levels of activated microglia were observed across all groups, a greater number was found in B-S transplants. In summary, we show that the effect of tissue preparation on graft morphology is contingent on the age of donor tissue used. The presence of microglial activation in all groups highlights the host immune response as an important consideration in mouse transplantation.
A PEG-Based Hydrogel for Effective Wound Care Management
Authors: Chen Sen-Lu , Fu Ru-Huei , Liao Shih-Fei , Liu Shih-Ping , Lin Shinn-Zong , Wang Yu-Chi
Published: April 2018

It is extremely challenging to achieve strong adhesion in soft tissues while minimizing toxicity, tissue damage, and other side effects caused by wound sealing materials. In this study, flexible synthetic hydrogel sealants were prepared based on polyethylene glycol (PEG) materials. PEG is a synthetic material that is nontoxic and inert and, thus, suitable for use in medical products. We evaluated the in vitro biocompatibility tests of the dressings to assess cytotoxicity and irritation, sensitization, pyrogen toxicity, and systemic toxicity following the International Organization for Standardization 10993 standards and the in vivo effects of the hydrogel samples using Coloskin liquid bandages as control samples for potential in wound closure.