Reduction of carbamylated albumin by extended hemodialysis

Introduction Among conventional hemodialysis (CHD) patients, carbamylated serum albumin (C‐Alb) correlates with urea and amino acid deficiencies and is associated with mortality. We postulated that reduction of C‐Alb by intensive HD may correlate with improvements in protein metabolism and cardiac function. Methods One‐year observational study of in‐center nocturnal extended hemodialysis (EHD) patients and CHD control subjects. Thirty‐three patients receiving 4‐hour CHD who converted to 8‐hour EHD were enrolled, along with 20 controls on CHD. Serum C‐Alb, biochemistries, and cardiac MRI parameters were measured before and after 12 months of EHD. Findings EHD was associated with reduction of C‐Alb (average EHD change ?3.20 mmol/mol [95% CI ?4.23, ?2.17] compared to +0.21 [95% CI ?1.11, 1.54] change in CHD controls, P < 0.001). EHD was also associated with increases in average essential amino acids (in standardized units) compared to CHD (+0.38 [0.08, 0.68 95%CI]) vs. ?0.12 [?0.50, 0.27, 95% CI], P = 0.047). Subjects who reduced C‐Alb more than 25% were found to have reduced left ventricular mass, increased urea reduction ratio, and increased serum albumin compared to nonresponders, and % change in C‐Alb significantly correlated with % change in left ventricular mass. Discussion EHD was associated with reduction of C‐Alb as compared to CHD, and reduction of C‐Alb by EHD correlates with reduction of urea. Additional studies are needed to test whether reduction of C‐Alb by EHD also correlates with improved clinical outcomes.     

Multi‐threshold and multi‐input DNA logic design style for profiling the microRNA biomarkers of real cancers

Early detection of cancer is very critical because it can reduce the treatment risk and cost. MicroRNAs (miRNAs) have been introduced in recent years as an efficient class of biomarkers for cancer early detection. Now, real‐time polymerase chain reaction has been used to profile the miRNA expression, which is costly, time consuming and low accuracy. Most recently, DNA logic gates are used to detect the miRNA expression level that is more accurate and faster than previous methods. The DNA‐based logic gates face with serious challenges such as the large complexity and low scalability. In this study, the authors proposed a methodology to design multi‐threshold and multi‐input DNA‐based logic gates in response to specific miRNA inputs in live mammalian cells. The proposed design style can simultaneously recognise multiple miRNAs with different rising and falling thresholds. The design style has been evaluated on the lung cancer biomarkers and the experimental results show the efficiency of the proposed method in terms of accuracy, efficiency and speed.Inspec keywords: DNA, logic design, biocomputing, RNA, molecular biophysics, logic gates, lung, genetics, cellular biophysics, cancer, biology computing, enzymes, biosensorsOther keywords: falling thresholds, specific miRNA inputs, multiinput DNA‐based logic gates, low scalability, DNA‐based logic gates face, miRNA expression level, DNA logic gates, low accuracy, time consuming, real‐time polymerase chain reaction, cancer early detection, treatment risk, cancers, microRNA biomarkers, multiinput DNA logic design style, multithreshold, lung cancer biomarkers     

Surveillance cultures of tunneled cuffed catheter exit sites in chronic hemodialysis patients are of no benefit

Catheter-related infections are a major cause of morbidity and mortality in hemodialysis (HD) patients. This study evaluated the utility of surveillance swab cultures (Ssc) of tunneled cuffed catheter (TCC) exit sites as a prediction and prevention strategy for infection. A 6-month prospective-controlled trial with 94 chronic HD patients with a TCC who received monthly Ssc and were stratified by dialysis day into topical therapy based on Ssc results (Group A) or no therapy (Group B). Outcomes were exit site infection (ESI) and catheter-associated bacteremia (CAB). The overall monthly prevalence of positive Ssc was 14.9%. There was no difference in the number of positive Ssc (17.7% vs. 11.6%, p > 0.05) or ESI (19.6% vs.16.3%, p > 0.05) between Groups A and B, respectively. Catheter-associated bacteremia was higher in Group A (17.7% vs. 4.7%, p = 0.05). There were significantly more ESI in the patients treated for a positive Ssc. In Group A, the incidence of ESI was significantly higher in those treated for a positive vs. negative Ssc (55% vs. 12%, p = 0.009) and CAB rates trended higher with positive Ssc (22.2% vs. 16.7%, p > 0.05). The strategy of treating positive surveillance cultures is not beneficial. Positive Ssc do not predict the occurrence of catheter-related infection, and treatment of these cultures may lead to increased infection rates.     

Short and long alteplase dwells in dysfunctional hemodialysis catheters

Background: Hemodialysis catheter dysfunction (CD) is the inability to attain adequate blood pump speeds (BPS) and is attributed to thrombus or catheter malposition; alteplase (TPA) is often given in a variety of dwell times to treat CD. The purpose of this study was to determine if TPA dwell time affects short‐ or long‐term catheter patency rates. Methods: Sixty hemodialysis (HD) patients with CD, as defined by BPS of < 250 mL/min, were randomized to receive either 1‐ or > 48‐hr (to subsequent HD run) TPA dwell. The primary outcomes were catheter patency (BPS of > 250 mL/min) at the subsequent HD run and catheter patency at 2 weeks. The secondary outcome was the time from study entry to the next catheter intervention (including subsequent TPA installation). Results: After TPA installation, a 78% overall catheter patency rate was observed at the subsequent HD run, falling to 48% patency at 2 weeks. There is no statistically significant difference between the short and long TPA dwell groups for catheter patency at the subsequent HD run (76.9% vs. 79.4%) or at 2 weeks (42.3% vs. 52.9%). Multivariate analysis demonstrates that the use of TPA on two or more previous occasions is a predictor of TPA failure both at the subsequent HD run and at 2 weeks. TPA installation achieves a median catheter function time of only 14 days, after which CD reoccurs. Conclusion: This study demonstrates that although patency for the next HD run can be achieved with either short or long TPA dwell, neither is reliable in terms of long‐term patency. Strategies that employ TPA for CD are temporary and allow a 2‐week window during which more definitive therapies for HD access should be sought.     

Hemodynamic and Volume Changes during Hemodialysis

Background: Volume overload is a factor in the hypertension of hemodialysis (HD) patients. Fluid removal is therefore integral to the hemodialysis treatment. Fluid removal by hemodialysis ultrafiltration (UF) may cause intradialytic hypotension and leg cramps. Understanding blood pressure (BP) and volume changes during UF may eliminate intradialytic hypotension and cramps. Studies (S1, S2, and S3) were carried out to determine the amount and direction of changes in body fluid compartments following UF and to determine the relationships between BP, changes in blood volume (ΔBV), central blood volume (CBV), cardiac output (CO), peripheral vascular resistance (PVR) plus total body water (TBW), and intra‐ and extracellular fluid volumes (ICF, ECF) in both the whole body and body segments (arms, legs, trunk). Methods: Indicator dilution technology (Transonic) was used for CBV, CO, and PVR; hematocrit monitoring (Crit‐Line) was used for ΔBV segmental bioimpedance (Xitron) for TBW, ICF, and ECF. Results: S1 (n = 21) showed UF sufficient to cause ΔBV of ?7% and lead to minor changes (same direction) in CBV and CO, and with cessation of UF, vascular refilling was preferential to CBV. S2 (n = 20) showed that predialysis HD patients are ECF‐expanded (ECF/ICF ratio = 0.96, controls = 0.74 [P < 0.0001]) and BP correlates with ECF (r = 0.47, P = 0.35). UF to cause ΔBV of ?7% was associated with a decrease in ECF (P < 0.0001) and BP directly (r = 0.46, P = 0.04) plus ΔBV indirectly (r = ?0.5, P = 0.024) correlated with PVR, while CBV and CO were maintained. S3 (n = 11) showed that following UF, total‐body ECF changes were correlated with leg ECF (r = 0.94) and arm ECF (r = 0.72) but not trunk ECF. Absolute ECF reduction was greatest from the legs. Conclusions: Predialysis ECF influences BP and UF reduces ΔBV and ECF, but CBV and BP are conserved by increasing PVR. ECF reduction is mainly from the legs, hence may cause cramps. Intradialytic hypotension is caused by failure of PVR response.     

Effect of surface‐modified zinc oxide as cure activator on the properties of a rubber compound based on NR/SBR

Zinc oxide (ZnO) and nano‐zinc oxide (nZnO) were surface modified by polyethylene glycol (PEG) and poly propylene glycol (PPG). Modification of particles were controlled by transmission electron microscopy, Brunauer, Emmett, Teller specific surface area measurement, infrared (IR) spectroscopy, and differential scanning calorimetry. IR spectra were shown that the interactions between surface modifiers and particles are hydrogen bonding. Modified particles were applied as an activator in vulcanization of natural rubber/styrene butadiene rubber (NR/SBR) blend. Dispersion of modified particles in rubber matrix was investigated by scanning electron microscopy and shown good results. Blend properties were improved by using modified particles. These improvements were due to the better hydrophobicity of modified particles, which were more compatible with nonpolar rubber matrix and caused better participation in curing process. Modification by PEG and PPG were shown better compound properties for ZnO and nZnO, respectively. Application of ZnO‐modified particles were presented better compound properties in comparison with nZnO‐modified particles. It has confirmed more effective mixing of ZnO‐modified particles in rubber matrix by using ordinary mixers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Combination hemodialysis and centrifugal therapeutic plasma exchange: 18 years of Canadian experience

Hemodialysis (HD) and therapeutic plasma exchange (TPE) are extracorporeal treatments that may both be required in the same patient. When provided separately, 7–8 hours of therapy time is required. Simultaneous administration of both therapies can reduce time and personnel requirements. We report our 18‐year institutional experience with combination HD and centrifugal TPE therapy. During combination therapy, the TPE circuit is attached to the HD circuit through an extension blood line connected to the HD venous return line, allowing simultaneous operation of both circuits. The HD circuit is anticoagulated with heparin and the TPE circuit with regional citrate. Blood flow rates through the HD circuit can reach 350 mL/min with plasma removal rates in the TPE circuit up to 60 mL/min. Ninety‐two patients received a total of 621 treatments between December 1993 and July 2011. All treatments were completed within 4 hours. No major treatment‐related adverse events occurred and less than 10% of treatments were complicated by minor events. Main indications for treatment were ANCA (anti‐neutrophilic cytoplasmic antibody) vasculitis (n = 25), Goodpasture's/antiglomerular basement membrane disease (n = 24), adult thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (n = 24), and acute antibody‐mediated renal transplant rejection (n = 8). Overall rates of renal recovery, in‐hospital mortality, and overall mortality at 18‐year follow‐up were 45% (41/ 92), 2% (2/92), and 21% (19/ 92), respectively, compatible with published literature. Combination HD and TPE is safe, efficient, and requires less human resources and time than conventional sequential therapy. It should be considered in patients whose treatment regimen includes HD and TPE.     

Ultrasound-guided cutaneous nerve chemo-ablation for severe access site neuropathic pain—A case report

Neuropathic pain at the cannulation site is challenging, both for the patient and the dialysis team. We present a case of a middle-aged man on chronic hemodialysis, who developed excruciating pain at the cannulation area without incident, limiting his dialysis sessions. Multidisciplinary collaboration allowed identification of the cutaneous nerve—the inferior lateral cutaneous nerve of the arm, relaying his pain. Subsequent ultrasound-guided phenol chemoablation resulted in the complete resolution of his pain and allowed continued use of the well-functioning fistula for dialysis.