bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of Different Decellularization Procedures of Porcine Heart Valves
Authors: Kasimir M.-T. , Rieder E. , Seebacher G. , Silberhumer G. , Wolner E. , Weigel G. , Simon P.
Published: January 2018

Background

Tissue engineering of heart valves should avoid the disadvantages of conventional prostheses. In this study we tested different decellularization procedures for their potential of cell removal and their ability to preserve the matrix.

Methods

Specimens of porcine aortic and pulmonary roots were treated with either trypsin or sodium-dodecyl-sulfate (SDS) or Triton-X 100® and sodium-deoxycholate with a range of concentrations. Tissue samples were then processed for scanning electron microscopy and laser scanning microscopy.

Results

Trypsin achieved only incomplete decellularization and caused severe structural alterations of the matrix. In contrast SDS removed cells completely but caused strong structural alterations. Treatment with Triton-X100® and sodium-deoxycholate achieved both complete decellularization and preservation of the matrix structure.

Conclusion

Techniques of decellularization are highly variable in efficiency and matrix preservation and was best achieved in our study with Triton-X100® and sodium deoxycholate.
Ex Vivo Biocompatibility of a New ß2-Microglobulin Hemoperfusion Polymer
Authors: Wendler T. , Duhr C. , Bosch T.
Published: January 2018

ß2-microglobulin (ß2-m) is an 11.8 kD protein that is excreted by the kidneys. In renal insufficiency, it accumulates in the body and can result in AB amyloidosis with bone and joint destruction.

Four modifications of a new ß2-m adsorbent material were tested for biocompatibility with human whole blood. 500 ml of heparinized blood from healthy human donors was perfused ex vivo through minicolumns (adsorber beads: divinylbenzene with different biocompatible coatings) in the single-pass mode. Blood samples were taken from the antecubital vein before and at the column outlet during the 50 min test runs.

Red and white cell counts remained virtually constant. No signs of hemolysis could be detected. Thrombogenicity of the columns was low as shown by the insignificant platelet loss, only slight platelet activation and moderate thrombin-antithrombin formation. There was no activation of leukocytes nor monocytes. Complement and bradykinin activation was minimal. Electrolyte concentrations and pH remained essentially constant.

In conclusion, this new ß2-m adsorbent material exhibited favorable biocompatibility features in our ex vivo model and is thus a promising candidate for future clinical ß2-m hemoperfusion studies in patients.
The Acid-Base Effects of Continuous Hemofiltration with Lactate or Bicarbonate Buffered Replacement Fluids
Authors: Tan H.K. , Uchino S. , Bellomo R.
Published: January 2018

Objective

To evaluate, quantify and compare the effects of continuous veno-venous hemofiltration (CVVH) with lactate or bicarbonate-buffered replacement fluids on acid-base balance.

Design

Randomized double crossover study.

Setting

Intensive Care Unit of Tertiary Medical Center.

Participants

Eight patients with severe acute renal failure.

Interventions

Random allocation to either 2 hours of isovolemic lactate-buffered (treatment A) CVVH or 2 hours of bicarbonate-buffered (treatment B) CVVH with cross over and with same procedure repeated the following day (double cross over).

Measurements and Results

Timed collections of arterial blood and ultrafiltrate (UF), measurement of blood and UF gases and lactate concentrations and calculation of buffer-base mass balance. At baseline, both groups of patients had a similar, slight metabolic alkalosis (pH: 7.45 vs. 7.45; BE 3.9 mEq/L for treatment A and 4.0 for treatment B) and a serum bicarbonate of 28.1 mmol/L for treatment A vs. 28.3 mmol/L for treatment B; all NS. This alkalosis was present despite slight hyperlactatemia in both groups (A: 2.4 mmol/L vs. B 2.8 mmol/L; NS). Within 60 minutes of treatment, however, treatment A led to a significantly higher lactate concentration (3.9 vs 2.5 mmol/L; p=0.0011), a significantly lower BE (2.3 vs 4.1 mEq/L; p=0.0019) and a significantly lower bicarbonate concentration (26.7 vs. 28.3 mmol/L; p=0.0038) in the presence of an unchanged PaCO2. These differences persisted during the study period. The UF of patients receiving treatment A contained more lactate (10.2 vs 2.9 mmol/L; p<0.0001) and less bicarbonate (25.6 vs. 30.8 mmol/L; p<0.0001) than treatment B resulting in a mean buffer-base balance of +20.4 mEq/h compared to −2.6 mEq/h for treatment B; p<0.0001).

Conclusions

CVVH with lactate-buffered replacement fluids induces iatrogenic hyperlactatemia. Such hyperlactatemia is associated with an acidifying effect despite a positive buffer-base balance.
Computerized Generation of Circadian Sensor Modal Days with Continuous Glucose Monitoring for Comparison of Various Insulin Regimens Based on Insulin Glargine in Type 1 Diabetes
Authors: Howorka K. , Pumprla J. , Gabriel M. , Thoma H. , Schabmann A.
Published: January 2018

Aim

Our aims were (1) to design and standardize a statistical approach for data reduction in continuous glucose monitoring, allowing comparison of circadian glycemic patterns in therapeutic subcohorts of patients with type 1 diabetes, and (2) to investigate the applicability of this approach for CGMS® assessment in clinical study of basal insulin replacement quality with various timings of basal injections (pre-breakfast, dinner, bedtime) of a new insulin analog.

Methods

Prospective randomized three-arm parallel study with switch over after 6 months for another 3 months of free choice injection time point (options pre-breakfast, pre-dinner and bedtime) of the new insulin analog in 16 type 1 diabetic subjects on functional insulin treatment (FIT: basal, prandial and correctional dosages). CGMS® was used at the end of each follow up period of a clinical study. Representative daily profiles were off-line computed as “circadian sensor modal days” for each insulin regimen consisting of consecutive means of hourly glucose values.

Results

Although the overall quality of glycemic control (HbAIC) for different regimens did not reach statistical differences, CGMS® displayed slightly divergent maximal swings in the course of glycemia (p=0.04–0.08) and allowed – with delineated data reduction procedure – a reliable between treatment comparison.

Conclusion

Off-line computation of “hourly circadian sensor modal days” for data reduction can be effectively used with CGMS® for description of circadian glycemic patterns in type 1 diabetes. (Int J Artif Organs 2003; 26: 728–34)
A Novel Bioartificial Liver Containing Small Tissue Fragments: Efficiency in the Treatment of Acute Hepatic Failure Induced by Carbon Tetrachloride in Rats
Authors: Soloviev V. , Hassan A.N.E. , Akatov V. , Lezhnev E. , Ghaffar T.Y.A. , Ghaffar Y.A.
Published: January 2018

The efficiency of a new bioartificial liver (BAL) containing small tissue fragments in the treatment of acute hepatic failure induced by carbon tetrachloride in rats was evaluated. A day after injection (i.p.) of CCl4 the animals were connected to a BAL containing liver fragments (fragment BAL) and a BAL containing no liver fragments (no-fragment BAL), and extracorporeal hemoperfusion was carried out for 4 h. The activities of alanine transaminase and lactate dehydrogenase as well as the concentrations of ammonia, glucose, urea, and amino acids in plasma were measured. A tendency to the stabilisation of ammonia, glucose, phenylalanine, tyrosine, and other amino acids was revealed at the end of hemoperfusion in poisoned rats connected to the fragment BAL. A statistically significant difference in survival between the animals connected to the fragment BAL and no-fragment BAL was found. The results obtained indicate that the bioreactor containing small liver fragments is effective in the treatment of acute hepatic failure in animals.
A Collagen-Based Scaffold for a Tissue Engineered Human Cornea: Physical and Physiological Properties
Authors: Doillon C.J. , Watsky M.A. , Hakim M. , Wang J. , Munger R. , Laycock N. , Osborne R. , Griffith M.
Published: January 2018

Stabilized collagen-glycosaminoglycan scaffolds for tissue engineered human corneas were characterized. Hydrated matrices were constructed by blending type I collagen with chondroitin sulphates (CS), with glutaraldehyde crosslinking. A corneal keratocyte cell line was added to the scaffolds with or without corneal epithelial and endothelial cells. Constructs were grown with or without ascorbic acid. Wound-healing was evaluated in chemical-treated constructs. Native, noncrosslinked gels were soft with limited longevity. Crosslinking strengthened the matrix yet permitted cell growth. CS addition increased transparency. Keratocytes grown within the matrix had higher frequencies of K+ channel expression than keratocytes grown on plastic. Ascorbic acid increased uncrosslinked matrix degradation in the presence of keratocytes, while it enhanced keratocyte growth and endogenous collagen synthesis in crosslinked matrices. Wounded constructs showed recovery from exposure to chemical irritants. In conclusion, this study demonstrates that our engineered, stabilized matrix is well-suited to function as an in vitro corneal stroma.
Effects of Dialyzer Membrane on Serum Albumin Levels in Patients Receiving Hemodialysis
Authors: Rault R.M.
Published: January 2018

Biocompatibility of the dialyzer membrane has been thought to affect the nutritional status in patients receiving chronic hemodialysis. In a series of patients treated in an outpatient dialysis unit, serum albumin was measured before and after changing the dialyzer membrane from one of cellulose to one of polysulfone. There were 48 patients (25 men and 23 women) who had been on dialysis for a mean duration of 78.6 months. The follow-up period was at least 6 months for each type of membrane. Delivered dose of dialysis was higher using the polysulfone membrane but serum albumin was not affected by a change to the more biocompatible membrane. Nutritional considerations are not important in choosing a membrane for dialysis.
Design of a Continuous Flow Centrifugal Pediatric Ventricular Assist Device
Authors: Throckmorton A.L. , Wood H.G. , Day S.W. , Song X. , Click P.C. , Allaire P.E. , Olsen D.B.
Published: January 2018

Thousands of pediatric patients suffering from cardiomyopathy or single ventricular physiologies secondary to debilitating heart defects may benefit from long-term mechanical circulatory support due to the limited number of donor hearts available. This article presents the initial design of a fully implantable centrifugal pediatric ventricular assist device (PVAD) for 2 to 12 year olds. Conventional pump design equations, including a nondimensional scaling approach, enabled performance estimations of smaller scale versions (25 mm and 35 mm impeller diameters) of our adult support VAD. Based on this estimated performance, a computational model of the PVAD with a 35 mm impeller diameter was generated. Employing computational fluid dynamics (CFD) software, the flow paths through the PVAD and overall performance were analyzed for steady state flow conditions. The numerical simulations involved flow rates of 2 to 5 LPM for rotational speeds of 2750 to 3250 RPM and incorporated a k-ε fluid turbulence model with a logarithmic wall function to characterize near-wall flow conditions. The CFD results indicated best efficiency points ranging from 25% to 28%, which correlate well with typical values of blood pumps. The results further demonstrated that the pump could deliver 2 to 5 LPM at 70 to 95 mmHg for desired physiologic conditions in resting 2 to 12 year olds. Scalar stress levels remained below 300 Pa, thereby signifying potentially low levels of hemolysis. Several flow regions in the pump exhibited signs of vortices, retrograde flow, and stagnation points, which require optimization and further study. This CFD model represents a reasonable starting point for future model enhancements, leading to prototype manufacturing and experimental validation.
Influence of Hepatitis B Virus Virema upon Serum Aminotransferase Activity in Dialysis Population
Authors: Fabrizi F. , Mangano S. , Alongi G. , Bisegna S. , Finazzi S. , Lunghi G. , Ponticelli C.
Published: January 2018

Background

The control of the spread of hepatitis B virus (HBV) infection within dialysis units has been one of the major advances in the management of patients with end-stage renal disease (ESRD). However, clinical and biochemical expression of HBV in dialysis patients have not been adequately addressed. Elevated values of serum aminotransferase activity are a sensitive measure of hepatocellular injury, but the role of HBV infection in the development of liver disease among dialysis patients has not been adequately analysed. Also, the clinical impact related to the virological characteristics of HBV in dialysis has not been evaluated.

Methods

Demographic, biochemical and virological data from 727 patients undergoing chronic dialysis in seven dialysis units in northern Italy were collected in order to assess the biochemical consequences related to the presence of HBV infection in this population. We have measured by RT-PCR technology the titers of HBV viremia in HBsAg positive patients receiving dialysis.

Results

Univariate analysis showed that AST and ALT values were significantly higher in HBsAg positive/HBV DNA positive than HBsAg negative patients on dialysis; AST, 22.86±31.34 vs. 14.19±9.7 IU/L (P=0.00001); and ALT, 25.07±41.59 vs. 13.9±41.59 IU/L (P=0.00001). In the subgroup of HBsAg positive patients, the frequency of detectable HBeAg in serum was 14.9% (7/47). The median value of HBV DNA in patients with detectable HBV DNA in serum was 2.160 × 103 copies/mL (range, 2.5 × 102 - 4 × 106 copies/mL). HBsAg positive/HCV positive patients had higher aminotransferase activity than other subgroups (P=0.0001). Multivariate analysis showed a significant and independent association between detectable HBsAg/HBV DNA in serum and AST (P=0.00001) and ALT (P=0.0001) activity. AST and ALT levels were lower in dialysis than healthy individuals – this finding persisted in age- and gender-matched comparisons.

Conclusions

The HBV viral load in HBsAg positive patients receiving maintenance dialysis is not high. HBsAg positivity with detectable HBV DNA in serum is a strong and independent predictor of raised aminotransferase activity among dialysis patients. HBsAg positive patients had greater aminotransferase activity than HBsAg negative individuals even if both the groups had mean aminotransferase levels within the normal range considered for healthy population. Clinical trials aimed at identifying the best cut-off value to enhance the diagnostic yield of AST/ALT for detecting HBV in dialysis population are under way.
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.
Assessment of the Combined Effect of Plasma Exchange and Plasma Perfusion on Patients with Severe Hepatitis Awaiting Orthotopic Liver Transplantation
Authors: Wang Y.-J. , He N.-H. , Wang Z.-W. , Niu R.-Z. , Liu J. , Wen H.-W. , Li J.-J. , Li M.-D. , Wang Y.-M.
Published: January 2018

To determine if plasma exchange combined with plasma perfusion is a reliable and effective temporary liver support treatment for patients on the waiting list for OLT, we tested this method in 5 patients with end-stage and 3 patients with middle-stage severe hepatitis. Four patients were successfully controlled until a donor liver was available 4 to 13 days later. In contrast, the remaining 4 patients were not adequately controlled by this treatment and experienced aggravated disease progression, dying 3 to 8 days after treatment while still awaiting OLT. Of those 4 patients who received OLT, 2 patients died from multi-organ failure caused by hepatic failure, while the other 2 survived. These findings show that plasma exchange combined with plasma perfusion provides temporary support for some patients on the waiting list for OLT. The ability of patients to successfully bridge to OLT is closely associated with the degree of liver failure, complications, multi-organ failure, and the length of the waiting period for a donor liver.
Fibrin/Schwann Cell Matrix in Poly-Epsilon-Caprolactone Conduits Enhances Guided Nerve Regeneration
Authors: Galla T.J. , Vedecnik S.V. , Halbgewachs J. , Steinmann S. , Friedrich C. , Stark G.B.
Published: January 2018

The goal of this study was to investigate if a three dimensional matrix, loaded homogeneously with Schwann cells and the neurotrophic factor LIF (leukemia inhibitory factor), enhances regeneration in a biodegradable nerve guidance channel as compared to non-structured cell suspensions. Therefore a 10 mm nerve gap in the buccal branch of the rat's facial nerve was bridged with tubular PCL (poly-epsilon-caprolactone) conduits filled with no matrix, Schwann cells, the three dimensional fibrin/Schwann cell matrix or the fibrin/Schwann cell matrix added with LIF. Four weeks after the nerve defects were bridged histological and morphometric analyses of the implants were performed. In conclusion, the three dimensional fibrin/Schwann cells matrix enhanced the quantity and the quality of peripheral nerve regeneration through PCL conduits. The application of LIF prevented hyperneurotization. Therefore, tissue engineered fibrin/Schwann cells matrices are new invented biocompatible and biodegradable devices for enhancing peripheral nerve regeneration as compared to non-structured cell suspensions without neurotrophic factors.
Convective-Controlled Double High Flux Hemodiafiltration: A Novel Blood Purification Modality
Authors: Pisitkun T. , Eiam-Ong S. , Tiranathanagul K. , Sakunsrijinda C. , Manotham K. , Hanvivatvong O. , Suntaranuson P. , Praditpornsilpa K. , Chusil S. , Tungsanga K.
Published: January 2018

Convective-controlled double high flux hemodiafiltration (CC-DHF) was set-up using two high flux dialyzers. The convection occurred in the first while the fluid replacement took place in the second dialyzer. The system of CC-DHF basically resembled that of hemodiafiltration. CC-DHF was performed in 9 chronic hemodialysis Thai patients who had been treated with high flux hemodialysis for at least 6 months. When compared with high flux hemodialysis, CC-DHF could provide higher Kt/Vurea (2.4 ± 0.4 vs. 2.0 ± 0.4, p<0.05) and ß2-microglobulin clearance (106.2 ± 15.4 vs. 48.9 ± 6.1 ml/min, p<0.01). Following 6-month therapy of CC-HDF, the predialysis ß2-microglobulin levels were reduced by 12.7% while the values of Kt/Vurea were consistently higher than 2.7. The quality of life consistently improved during the 6 months of CC-DHF treatment. There were no differences in clinical and technical complications between CC-DHF and high flux hemodialysis. In conclusion, CC-DHF could provide performance comparable to hemodiafiltration without the need for expensive hemodiafiltration machines.
Influence of Serum from Rats with Fulminant Hepatic Failure on Hepatocytes in a Bioartificial Liver System
Authors: Ito Y. , Eguchi S. , Kamohara Y. , Inuo H. , Yamanouchi K. , Okudaira S. , Yanaga K. , Furui J. , Kanematsu T.
Published: January 2018

Fulminant hepatic failure (FHF) is a life-threatening condition marked by many excessively increased unmetabolized toxins and growth factors. Recently developed bioartificial liver (BAL) systems containing hepatocytes can be used to treat patients with FHF. However, the behavior of these hepatocytes on exposure to FHF serum in vitro remains unclear. In the present study, we used FHF rat models and the sera from these rats (i.e., FHF serum) contained elevated inflammatory cytokines (TNF-α, IL-1ß, and IL-6), HGF, and TGF-ß1. In addition, 1×10 8 hepatocytes were harvested from the livers of inbred rats and incubated with microcarrier beads. Four hours later, the hepatocyte-coated beads were inoculated into a hollow-fiber module (=BAL system). FHF serum or normal control serum circulated for 6 hours through the BAL system. Expressions of mRNA for albumin, GST A1, CYP 1A2, OTC and c-fos were investigated by RT-PCR, and PCNA staining was performed before and after perfusion. The expressions of albumin, GST A1, and CYP 1A2 mRNAs were markedly decreased, whereas those of OTC and c-fos were modestly decreased. PCNA positive cells were low and showed no difference between FHF and normal serum-exposed hepatocytes. In conclusion, the exposure of hepatocytes to hypercytokinemia, including inflammatory cytokines and positive and negative growth factors, caused a loss in liver specific functions. This environment also failed to facilitate hepatocyte regeneration.
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.
Home Care Artificial Heart Monitoring System via Internet
Authors: Chung J. , Lee J.H. , Choi J. , Lee J. , Kim W.G. , Sun K. , Min B.G.
Published: January 2018

The availability of a remote management system, which provides both physiological-related information about the patient and device-related information about the implanted device, would be helpful during in vivo experiments or clinical trials involving artificial heart implantation. In order to be able to monitor the course of the in vivo experiment continuously regardless of the patient's location, an internet-based remote monitoring system was developed, which can monitor physiological-related information such as pressure (AoP, LAP, RAP, PAP) and flow data, as well as device-related information such as current, direction and pump operating conditions. The home care artificial heart monitoring system which we developed consists of four main components, which are the transcutaneous information transmission system (TITS), local monitoring station (LMS), data server station (DSS), and client monitoring station (CMS). The device-related information and physiological-related information can be transmitted in real time from a patient in a remote non-clinical environment to the specialist situated in a clinic depending on the current capabilities and availability of the internet. The local monitoring station situated at the remote site is composed of a data acquisition and preprocessing unit connected to a computer via its RS-232 port, and which communicate using a Java-based client-server architecture. The remote monitoring system so developed was used during an in vivo experiment of the artificial heart implantation for 2 months and performed successfully according to design specifications.
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.
Molecular Mechanisms of Acute Renal Failure following Ischemia/Reperfusion
Authors: Versteilen A.M.G. , Di Maggio F. , Leemreis J.R. , Groeneveld A.B.J. , Musters R.J.P. , Sipkema P.
Published: January 2018

Acute renal failure (ARF) necessitating renal replacement therapy is a common problem associated with high morbidity and mortality in the critically ill. Hypotension, followed by resuscitation, is the most common etiologic factor, mimicked by ischemia/reperfusion (I/R) in animal models. Although knowledge of the pathophysiology of ARF in the course of this condition is increasingly detailed, the intracellular and molecular mechanisms leading to ARF are still incompletely understood. This review aims at describing the role of cellular events and signals, including collapse of the cytoskeleton, mitochondrial and nuclear changes, in mediating cell dysfunction, programmed cell death (apoptosis), necrosis and others. Insight into the molecular pathways in the various elements of the kidney, such as vascular endothelium and smooth muscle and tubular epithelium leading to cell damage upon I/R will, hopefully, open new therapeutic modalities, to mitigate the development of ARF after hypotensive episodes and to promote repair and resumption of renal function once ARF has developed.
Prevention of Acute Renal Failure - Fluid Repletion and Colloids
Authors: Jakob S.M.
Published: January 2018

Hypovolemia alone or in conjunction with other factors is a main reason for acute renal failure in critically ill patients. Various crystalloid and colloid solutions are available to correct hypovolemia. Some of them have been implicated in impairment of renal function. Infusion of large amounts of sodium chloride is associated with increased incidence of nausea, vomiting and hyperchloremic metabolic acidosis. While gelatins and HES are preferred colloids in patients with normal kidney function, there is some evidence that the latter are associated with impaired renal function in patients with pre-existing kidney disease. Any hyperoncotic colloid given in large amounts may decrease glomerular filtration, and should therefore be combined with crystalloids.
Prevention of Acute Renal Failure: Role of Vaso-Active Drugs, Mannitol and Diuretics
Authors: Girbes A.R.J.
Published: January 2018

Evidence exists that acute renal failure (ARF) independently increases mortality risk in critically-ill patients. Therefore prevention of ARF seems of paramount importance. Preservation of renal blood flow and (sufficient) perfusion pressure favourably influences the prevention of renal function deterioration in the critically-ill septic patient. The first step to achieve this is infusion of fluids, either crystalloids or colloids, with the aim of optimal fluid resuscitation. Although “optimal fluid resuscitation” is poorly defined, in clinical practice it can be considered as the point where a certain preload is obtained, after which no further increase of cardiac output is observed with further fluid infusion. Vasoactive drugs can be added to this regimen in case of insufficient restoration of flow and especially perfusion pressure. The addition of norepinephrine can be of value if high doses of dopamine fail to restore perfusion pressure. No evidence exists that low-dose dopamine prevents renal failure and, therefore, dopamine should not be given for this indication. The use of diuretic agents can be harmful, as indicated by observational and cohort studies. Although mannitol flushes out intratubular casts and increases tubular flow, which is favorable in myoglobinuria or hemoglobinuria, so far no well designed clinical studies have demonstrated its efficacy in ARF. In conclusion, there is currently no convincing evidence for any benefit from diuretic agents and/or (low dose) dopamine in the prevention of ARF. High quality intenisve care and avoidance of harm is, therefore, the current standard of the prevention of ARF.
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.
Effects of Physical Exercise in Patients with End Stage Renal Failure, on Dialysis and Renal Transplantation: Current Status and Recommendations
Authors: Stefanović V. , Milojković M.
Published: January 2018

There is increasing evidence about the benefits of regular physical activity in the chronically ill. Patients with chronic renal failure prior to and after renal transplant are one of the target groups in which increased controlled physical activity is highly recommended. Significant atrophy and increased non-contractile tissue are present in the muscle of predialytic and patients on hemodialysis, which is associated with poor physical performance and poor outcome of renal disease. Thus, interventions to increase physical activity or otherwise address atrophy may improve performance and quality of life in these patients. Other abnormalities in these patients, such as metabolic impairments, anemia, and hormonal changes, especially insulin resistance and lipid disorders, could be also modulated by certain therapeutic agents and physical activity. Increasing activity levels in this target group could be particularly important since it is well established that controlled physical exercise reduces the risk of cardiovascular disease in the general population. Patients who participate in regular physical activity following transplant will have higher health-related fitness and quality of life compared to those who remain inactive. The potential risk of physical activity can be reduced by medical evaluation, risk stratification, careful supervision, and education
Augmentation of Butyrate-induced Differentiation of Human Hepatocyte by Cyclin E Over-expression
Authors: Yoon J.-H. , Gwak G.-Y. , Woo G.H. , Kim T.H. , Kim K.-A. , Kim C.Y. , Lee H.-S.
Published: January 2018

In mammalian cells, cellular differentiation into specific cell types is usually preceded by growth arrest. On the other hand, the induced differentiation may also be preceded by an enhanced G1–S transition of the cell cycle prior to the growth arrest. This suggests that an early increase in proliferation is in some way a prerequisite for subsequent differentiation. We therefore attempted to assess whether we could produce human hepatocytes with further differentiated functions by promoting G1-S transition in a butyrate-treated human hepatocyte cell line. A cyclin E-over-expressing cell line was established by transfecting human cyclin E cDNA. Upon butyrate treatment, the cyclin E-over-expressing cells exhibited a significantly increased albumin-secreting and ammonia-detoxifying capacity when compared to the control cells. In particular, the ornithine transcarbamylase activity was increased in these cells. Collectively, these results implicate that the cyclin E over-expression may augment the hepatocyte-specific functions during the butyrate-induced differentiation process of human hepatocytes by enhancing G1-S cell cycle transition.
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.
Phosphorus-Enriched Hemodialysis for the Treatment of Patients with Severe Methanol Intoxication
Authors: Chebrolu S.B. , Hariman A. , Eggert C.H. , Patel S. , Kjellstrand C.M. , Ing T.S.
Published: January 2018

Severe methanol poisoning requires treatment with prolonged and intensive hemodialytic therapy. Such treatment can engender either the de novo development of hypophosphatemia or the worsening of pre-existing hypophosphatemia. Phosphorus-enriched hemodialysis therapy can prevent the occurrence of this complication. We report three patients with severe methanol poisoning who were treated with phosphorus-enriched hemodialysis. Prevention or treatment of hypophosphatemia was successfully achieved with this dialytic technique.